Download INFLAMMATION AS IT RELATES TO OCULAR DISORDERS ®2010

INFLAMMATION AS IT RELATES TO OCULAR DISORDERS
S. African Version ®2010
LARRY J ALEXANDER
Invictus
Out of the night that covers me,
Black as the Pit from pole to pole,
I thank whatever gods may be
For my unconquerable soul.
In the fell clutch of circumstance
I have not winced nor cried aloud.
Under the bludgeonings of chance
My head is bloody, but unbowed.
Beyond this place of wrath and tears
Looms but the Horror of the shade,
And yet the menace of the years
Finds, and shall find, me unafraid.
It matters not how strait the gate,
How charged with punishments the scroll.
I am the master of my fate:
I am the captain of my soul.
William Ernest Henley
INTRODUCTION
Inflammation is a necessary and critical component of the healing system. In the
classic definition inflammation is composed of five components, heat, redness, swelling,
pain and loss of function but in reality it is possible to have some of these components
without the others manifesting. Inflammation is a result of the activation of the immune
system, and acute inflammation is critical to maintenance of health. Inflammation
functions to defend our system from bacteria, viruses, parasites, and trauma but must
be short acting to minimize tissue damage. Acute inflammation is modulated by the
immune system to take care of a problem then shut itself off. Chronic inflammation is
an issue that is a representation of the inflammatory process developing without proper
modulation and it becomes a smoldering fire that creates significant issues throughout
the bodily systems. Chronic inflammation is responsible for destabilizing cholesterol
deposits (heart attack and stroke), destroying nerve cells (dementias), proliferating
abnormal cells potentially transforming them to cancer, and impacting on devastating
disorders of the eye such as macular degeneration. The economic impact alone is
staggering. An estimated 25 Trillion dollars were spent for healthcare in America
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in 2008 with 70% of that (17.5 Billion dollars) attributable to chronic illnesses.
Chronic illnesses have inflammation as the epicenter of the process.
When reviewing the latest medical findings it becomes apparent that in addition to
issues such as environment and genetics, chronic inflammation is strongly associated
with lifestyle. Lifestyle includes exercise, smoking, alcohol consumption, diet and
psychological stress. The literature is replete with suggestions that happiness through
laughter is actually an important component of our lives. There is more to medicine
than pharmaceutical agents. Modulation has become a primary area of interest in the
development of strategies to battle chronic inflammation. Modulation is, however, the
watchword. Modulation implies balance and balance is the critical aspect of
management of inflammation. Errors have been made along the way in the approach to
chronic inflammation because suppression rather than modulation became the mode of
therapy. An excellent example of this is the COX 2 inhibitor debacle. COX 2 controls
vasodilation and anti thrombotic activity. COX 1 controls vascoconstriction and
thrombotic activity. If you suppress COX 2 rather than modulate COX 2, COX 1 takes
over allowing for vasoconstriction and thrombotic activity which precipitates cardiac
complications. COX 2 inhibitors created death. Again modulation or maintenance of
balance is the watchword.
Aspirin is another excellent approach to the management of inflammation as long as
one is not concerned about the potential side effects of long-term side effects such as
ulcers induced by reduced gastrointestinal secretions. In fact in the 1920s salicylates
were used extensively to manage diabetes. Diabetes is an inflammatory condition!
Non-steroidal anti-inflammatories (NSAIDS) and steroids are also very effective at
controlling inflammation but likewise have significant potential side effects. The new
wave of treatment are the TNF-alpha inhibitors that are superb at controlling
inflammation, but likewise have their sets of side effects.
An excellent example of the application of modulation exists in the product Restasis®.
Restasis is cyclosporine but has been prepared in such a manner that it impacts only on
the ocular system. Cyclosporine is an anti-rejection drug that can have tremendous
impact within the systemic system by altering white blood cell proliferation. The activity
of the inflammatory white blood cells on the eye creates a cascade of inflammation that
precipitates an intractable variant of dry eye. Utilization of the cyclosporine within the
confines of the eye actually balances (modulates) the white blood cell proliferation
allowing for maintenance of protection of the eye from bacterial and viral invasion while
minimizing the inflammatory activity. There is not SUPPRESSION of white blood cell
production which would be devastating to the immune system but rather modulation.
With the inflammatory activity minimized the eye is able to resume effective production
of tears. Of importance is the caution with Restasis® that it should not be used in active
inflammation nor with a history of herpetic disease as it may alter the normal immune
system protective activity.
THE PREQUEL
 ACUTE INFLAMMATION IS GOOD, CHRONIC INFLAMMATION IS BAD. BOTH
REPRESENT THE IMMUNE SYSTEM IN ACTION.
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 CHRONIC INFLAMMATION IS THE BASIS OF MOST CHRONIC DISEASE AND
INTRACTABLE OBESITY.
 MODULATION OF INFLAMMATION IS BALANCE AND IS CRITICAL FOR
SUSTAINING HEALTH.
 DIET, EXERCISE AND NUTRIENTS ARE NATURAL INFLAMMATORY
MODULATORS AND ARE MORE BENEFICIAL IN THE LONG TERM THAN
PRESCRIPTIVE AGENTS WHICH TYPICALLY SHUT DOWN SOME PHASE OF THE
IMMUNE SYSTEM PROCESS.
BASIS OF THE IMMUNE SYSTEM
The immune system is an integrated network of organs and cells that protect the host.
The system depends on self-regulation to dampen the potential for self -destruction or
autoimmune reactions. The balance in the system ( immunomodulation ) is critical to
the overall health of the immune system.
While the primary function of the immune system is to fight off invading organisms
(virus, bacteria, fungi, parasites) and to work to control aberrant growths such as tumor
cells, it also functions in the allergic and inflammatory responses. This action impacts
directly on one of the major issues facing eye doctors today, the issues of dry eye,
macular degeneration and glaucoma. Factors that may impact negatively on the
immune system include malnourishment, stress, immuno-compromising organisms
(HIV), illness, and emotion. The basis for the action of the immune system is the
antigen (foreign substance) and antibody (the specific protein formed to destroy the
invader). The antigen often resides on the surface of a bacteria or virus as a protein
and combines with the antibody to produce an immune response. Antibodies are
protein molecules synthesized by plasma cells, which are derived from B-lymphocytes.
An allergen is a protein antigen that produces hypersensitivity.
To better understand inflammation and the immune system, a clinical relationship
should be addressed. Clinically there is a cascade of reactions triggered when the body
is subjected to infection, trauma or injury. When invaded, the body has specialized cells
and chemicals distributed throughout organs that alert the immune system. Some of the
cells like the mast cells, release a chemical that increases capillary leakage. This fluid
then impedes the invasion allowing the immune system to mobilize. The macrophages,
which are the garbage-collectors of the system release more chemicals, calling for more
assistance in cleaning up the mess. The battle ensue and the clean up occurs. A halt
must then occur to minimize further damage from chronic inflammation.
The following play, “The Invasion of the Virus” illustrates the action of the immune
system when a virus is introduced into the system. The specifics of each component
will be addressed further.
Response of the Immune System to Invasion
The Screenplay-The Invasion of the Virus
The Basic Immune System-The Virus Model
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The Players
Virus
Macrophage
Helper T-Cell
A protein coated package of genetic information that must use the
machinery of a host cell to permit its own replication.
A white blood cell that engulfs and digests debris foreign to its
system. Macrophages also recruit helper T-Cells.
A white blood cell produced in the thymus that identifies a specific
enemy and rushes to the spleen and lymph nodes where it
stimulates the production of other cells to fight the
invasion(infection).—Th-Cell
Killer T-Cell
A white blood cell that is recruited and activated by Th-Cells and
specializes in killing cells that have been invaded by foreign
organisms and cancer cells—Tk-Cell
B –Cell
A white blood cell that is the biological arms factory. The B-Cell
resides in the speen or lymph nodes where it is induced to replicate
by Th-Cells and then to produce antibodies.
Antibody
This Y-shaped protein molecule targets and neutralizes specific
invader. It may also tag the invader for attack by other cells or
chemicals.
Suppressor T -Cell A white blood cell that exists to slow or stop the activities of B-Cells
and T-Cells after an immune activity has succeeded. Ts-Cell
Memory T-Cell
A cell generated during the infection that may circulate in the blood
or lymph for years enabling the body to respond more quickly to a
subsequent invasion.
The Invasion of the Virus
Act 1- Recognition of the Enemy
Viruses invade the body and are consumed by macrophages, which seize the viral
antigens and display them on the macrophage surface. Certain Th cells are
programmed to read that antigen and bind to that macrophage-activating the Th cell.
These Th cells have both a self marker and a non-self marker-the antigen.
Act 2 - Amplification of Defenses
The activated Th cells then multiply and stimulate multiplication of killer T cells and B
cells sensitive to the invading virus. When the number of B cells increases, Th cells
signal them to start producing antibodies.
Act 3 - The Attack
Some viruses have entered into cells to start replication. Killer T cells will chemically
puncture these infected cells to disrupt viral replication. Antibodies then neutralize
the viruses by binding to their surfaces preventing further penetration of healthy
cells. Likewise, the antibodies precipitate chemical reactions that further destroy the
infected cells.
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Act 4 – Slowing Down and Shutting Down the Attack
After containment of the infection, suppressor T cells prevent the immune response
from spiraling out of control. Memory T and B cells are left to respond rapidly should
the same infection occur.
The Components of the Immune System
The Organs of the Immune System
The lymphatic system is composed of lymph fluid, lymphatic vessels, bone marrow,
lymph nodes, spleen and tonsils. The fluid is pumped through the system via the
muscles. If you don’t exercise, the fluid becomes stagnant. The bone marrow
produces stem cells that are destined to become immune cell variants. B-cells
develop in the bone marrow and reside in the lymph nodes. B-cells are modified by
T-cells to create antibodies. The lymph nodes are the centers for the congregation
of immune system cells.
The thymus is located in the upper chest in the front of the heart. T-cells are
matured in the thymus and then pass into the lymph system. Without mature Tcells, B-cells are unable to produce antibodies. The thymus typically shrinks with
age.
The Cells and Enzymes of the Immune System
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Antigen
An antigen is any substance, usually protein but never lipid, considered foreign to
the host. An antigen can combine with an antibody to produce an immune response.
An allergen is a large protein that produces a type 1 hypersensitivity reaction.
Antibody
An antibody is a protein molecule produced by plasma cells, which evolve from Bcells. The antibody has a unique configuration that combines with a specific antigen
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to create an immune complex.
Antigen Presenting Cells (APCs)
Antigen presenting cells are cell types that provide special receptors and mediators
to process antigen and communicate with B-cell antibodies and T-cells for antigen
binding and appropriate cellular response. A typical antigen-presenting cell would
be a macrophage.
Phagocytes and Granulocytes
Phagocytes include granulocytes (reside in the blood but may move into tissue when
needed), monocytes (reside in blood) and macrophages (reside within tissue).
When infection occurs, phagocytes invade the area to digest and destroy the
organism. They do not have specific receptors to identify the invader, as do other
immune cells, and are therefore non-specific in their attack. Macrophages also
secrete a variety of chemicals and also serve to help activate T-cells. The
granulocytes contain granules filled with chemicals that are active in the destruction
of organisms while also functioning in the inflammatory reaction. Mast cells are
granule-containing cells that exist in tissue only. Mast cells are critical components
in the allergic response. Pyrogens released from phagocytes induce fever to assist
in destruction of the invader. Inflammation is also an active response to eliminate
foreign material while preparing the site for repair. Specialized phagocytes are
found in organs throughout the body.
Basophils
Basophils are small circulating white blood cells that release histamine and
arachidonic acid in response to prostaglandin D2. Basophils are usually associated
with the early phase (4-6 hours) of the IgE mediated response.
Eosinophils
Eosinophils are large white blood cells activated by components of complement.
They release major basic protein, peroxidase and proteolytic enzymes that attack
microorganisms. Eosinophils are non-phagocytic.
Macrophages
Macrophages are principal Antigen Presenting Cells (APC) of the phagocytic
system. Macrophages reside in connective tissues, fat tissue and around small
vessels. Macrophages are critical for T-cell proliferation and secretion of molecules
in the immune response..
Mast cells
Mast cells are large cells found in the tissues of the body with a granulated surface
bound with IgE and several chemical mediators whose release is responsible for the
IgE mediated hypersensitivity reaction.
Monocytes
Monocytes are circulating white blood cells serving APC function. They are
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phagocytic with some monocytes entering tissue to become macrophages.
Neutrophils
Neutrophils are the most prevalent type of white cell in the blood. They are
phagocytic in nature and are the primary element in acute inflammation.
Platelets
Platelets are the smallest circulating cells and generate preformed inflammatory
mediators.
Complement
Complement refers to a combination of a series of protein enzymes that circulate to
act as catalysts in the antibody reactions. The enzymes are released in a cascade
with each reaction functioning to eliminate foreign substances. The complement
proteins also attract phagocytes. The complement system functions to assist in
inflammatory vasodilation, phagocytic exudation, phagocytic migration, phagocytic
direction, and the clearing of infectious agents from the host.
The Specific Immune Cells
The immune cells are also the white blood cells of the system and number about 1
trillion. Lymphocytes are produced in the marrow of the long bones from stem cells
and typically have a relatively long life with memory. As lymphocytes mature, some
remain in the marrow and develop into B-cells and others spread throughout the
lymph system. When the lymphocytes reach the thymus, they are converted to Tcells and taught to recognize one specific antigen and recognize “self versus nonself”. The thymus is very selective, allowing only the strongest of the T-cells to
survive. Variations of the lymphocyte-derived cells take on specific responsibilities.
Cells of the Immune System
Helper T-cells
Helper T-cells (Th) are also referred to as T4 or CD4 cells. Helper T-cells act by
binding to the antigen complex on the antigen presenting cell (APC) and producing
mediators. Their action is varied including facilitation of cytotoxic T-cells, secretion
of interleukin-2, which stimulates growth, abundance, and lethal ability of the
cytotoxic T-cells, secretion of proteins to facilitate the inflammatory response and
lethal strength of monocytes, and communication to the B-cells to produce
antibodies.
Two basic variations of T-cells are TH1 and TH2 that produce different lymphokines.
TH1 produces lymphokines that enhance the immune system to respond to virus,
bacteria, fungi or parasitic invaders. The TH1 also activate cytotoxic and suppressor
T-cells while also controlling the activity of the TH2 response. TH2 cells function in
the allergic reactions or antibody responses. TH2 responses increase antibody
production and release interleukin-6, which is involved in the inflammatory response.
IL-6 is a strong inflammatory marker. If TH2 dominates, destruction of cells of the
“self” occurs. These two T-cell variations must be in balance.
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Th1 and Autoimmune Diseases
Rheumatoid Arthritis
Type 1 Diabetes
Autoimmune Thyroiditis
Crohn’s Disease
Excess IL-12 and
TNF-alpha
Deficiency in IL-10
and Th2 Cytokines
Cytotoxic T-cells
Cytotoxic T-cells (Tc) are also referred to as killer T-cells. The cytotoxic T-cells have
specialized surface receptors that recognize specific antigens and attach to the
invading cells. They then inject a cytokine which directly destroys the antigen—
invader. The cytotoxic T-cell then also releases a factor that facilitates the attack of
the macrophages to clean up the site. Cytotoxic T-cells also have the ability to
secrete interferons that stop viral replication.
Suppressor T-cells
Suppressor T-cells function to shut down activity of the immune response after
several weeks of infection. The suppressor T-cell stops cytotoxic T-cells from
releasing cytokines and stops the production of antibodies. A normal ratio of helper
T-cells to suppressor T-cells is 2:1. If this ratio is altered B-cells continue to function
and may create a significant imbalance in the host.
B-cells
B-cells are derived from stem cells in bone marrow and serve to synthesize antibody
or serve as APC cells dependent or independent of T-Cells. T-dependent B-cells
serve as APCs to activate T-cells to secrete lymphokines that together with the
antigen, trigger the B-cell to develop into a plasma cell which then first produces
IgM. T-independent B-cells are triggered by weak antigens without T-cell assistance
to create IgM production.
B-cells are capable of responding to specific antigens by producing specific
antibodies. B-cells reside primarily in lymph nodes and typically do not circulate in
the blood. Each B-cell is specific to one particular antigen. When an invasion of a
foreign substance occurs, T-cells communicate to B-cells to start producing
antibodies. B-cells then become plasma cells that survive 4-5 days and produce
massive amounts of antibodies. Once antibodies are produced, they circulate in the
bloodstream to lock onto an antigen to destroy it. Antibodies coat the invader to
facilitate destruction by other cells. Some B-cells then memorize the invader
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antigens becoming memory B-cells. The memory B-cells may live for months to
years to protect the host from re-invasion.
Natural Killer Cells (NK cells)
Natural Killer cells seek out foreign invaders with no regard to specificity—similar to
phagocytes but are non-phagocytic in their attack. NK cells are activated by
interleukin-2. NK cells do not have memory and act to destroy by the release of toxic
enzymes (cytokines)—similar to cytotoxic T-cells. NK cells act without the helper Tcell and also have the ability to release interferons that stop viruses from replicating.
NK cells are also capable of killing tumor cells.
The Antibody Factory
When a B-cell encounters its triggering antigen, it gives rise to many large plasma cells
that then produce one specific antibody.
Antibodies
Nine classes of antibodies referred to as immunoglobulins (Ig) are produced in the
immune system. There are four types of IgG, two types of IgA, IgM, IgE, and IgD. IgG,
IgD and IgE are similar in appearance. These glycoproteins form the humoral (bodily
fluid) phase of the immune system. Each molecule is specific for one antigen, but also
may serve as complement fixation of phagocytosis.
IgE
IgE occupies only about 0.004%o serum immunoglobulins. IgE is the allergic
immunoglobulin. IgE exists in trace amounts and stimulates the release of histamines
from mast cells. IgE also triggers the inflammatory reaction.
IgD
IgD is a trace immunoglobin (0.2%). IgD is almost found exclusively inserted into the
membrane of B-cells where it is thought to regulate the B-cell activation.
IgA
IgA composes 15% of the total serum immunoglobins. IgA is considered the first line
of defense for the host as it exists in tears, milk, sweat and saliva. IgA is also
present in the mucous membranes even within the gastrointestinal tract.
IgG
IgG is the most abundant antibody composing 75% of the total serum immunoglobulin.
It exists in the blood and also enters tissue spaces. IgG functions to coat
microorganisms speeding their uptake by other cells in the system. IgG activates a
series of enzymes that enhances the digestion of invaders. There are four subclasses
of IgG that cross the placenta to protect newborns.
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IgM
IgM composes 10% of the total serum immunoglobins. IgM is prominent in the early
immune response and presents on the B-cell surfaces. IgM is large and operates in the
bloodstream to disable bacteria.
Cytokines
Cytokines are proteins secreted by monocytes (monokines), lymphocytes
(lymphokines), adipose cells (adipokines ) . The cytokines function to regulate
inflammatory or immune responses by recruiting other cells and substances. Cytokines
are considered biochemical messengers. Numbers of chemicals are included in the
category of cytokines serving multiple functions within the body including encouraging
cell growth, promoting cell activation and actually destroying cells. Included are
arachidonic acid, heparin, histamine, interferon, interleukin, leukotriene, peroxidase,
phospholipids, serotonin, thromboxane and tumor necrosis factor.
Put into a clinical perspective, excessive cytokines in the tear fluid present in response
to insult create a situation that attracts more inflammatory response and a worsening of
the condition. There are both pro-inflammatory and anti-inflammatory cytokines and the
system must maintain balance. While cytokines are critical to the overall immune
process the imbalance that is created with chronicity will exacerbate any systemic
condition.
ProInflammatory
Il-1 alpha and beta
Il-2
Il-6
Il-8
Il-12
Il-18
IFN-gamma
TNF-alpha
Cytokine Functions
AntiInflammatory
Il-10
Il-13
TNF-beta
Fractalkine
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Cytokines and Inflammation
Immune Trigger
Dendritic Cells
Antigen Presenting Cells
Macrophages
Activated B Cells
Activated T-Cells
Th1
Il-2
IFN-gamma
TNF-alpha
Il-10
Th2
Il-4
IL-5
Il-13
Cytokines and Inflammation
The Macrophage (APC) Determines the Type of Reaction
IL12
IL-4
Th0
Th1
Il-2
IFN-gamma
TNF-alpha
Il-10
Inflammatory
Th2
Il-4
IL-5
Il-13
Mostly Anti-Inflammatory
TNF-alpha
Cytokines figure into inflammatory reactions throughout the body and Tumor Necrosis
Factor alpha is one of the most potent. TNF-alpha is most influential in severe
chronicity and many new drugs, such as Enbrel®®, Remicade®® and Humira® work at
the TNF-alpha site to minimize signs and symptoms. TNF-alpha is also associated with
the evolution and side effects of metabolic syndrome. J Leukoc Biol 2005;78;819
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TNF-alpha and the Metabolic Syndrome
Physical Inactivity
Obesity
Hypertension
Dyslipidemia
Insulin Resistance
Interleukins
Interleukins are cytokines involved in inducing various responses within the immune
system. There are several variants, but this discussion will cover those with the
greatest impact on the ocular system.
Interleukins and vascular inflammation manifest in the following manner. The
inflammatory cytokine markers in the center column have short half-lives and have the
effect of increasing the plasma levels of other markers such as C-Reactive Protein
(CRP) and Fibrinogen. There is a mixed effect on fibrinogen and a consistent effect on
CRP. Gabay C, et al. N Engl J Med 1999;340:448-454.
CYTOKINES AND VASCULAR INFLAMMATION
INTERLEUKIN - 6
INTERLEUKIN – 1
TNF-ALPHA
TNF-BETA
+VE -VE
FIBRINOGEN
+VE
C-REACTIVE PROTEIN
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Interleukin-1
IL-1 is involved in inducing fever. IL-1 is produced primarily by macrophages. IL-1 is
also involved in T-cell production of IL-2.
Interleukin-2
IL-2 encourages helper T-cells to precipitate cytotoxic T-cell destruction of the invader.
IL-2 also communicates to all T-cells to release more IL-2. IL-2 is especially effective in
enhancing response against tumor cells. IL-2 is also a powerful immuno-modulator that
encourages further production of T-cells.
Interleukin-4
IL-4 enhances the B-cell production of antibodies (especially IgG and IgE). IL-4 also
stimulates helper T-cells and cytotoxic T-cells. Too much IL-4 promotes an allergic
response. Again the balance is critical.
Interleukin-6
IL-6 is released by macrophages, monocytes and some T-cells. IL-6 induces B-cells to
produce antibodies. Abnormal levels of IL-6 are associated with autoimmune
disorders, inflammation and allergic response. TH2-cell release of IL-6 is
associated strongly with autoimmune disorders such as psoriasis and paradoxically with
increased exercise. More will be discuss regarding this very important marker of
inflammation in the section on exercise and chronic inflammation.
Interferon
Interferons are involved most intimately in the defense of the host against viruses.
Several variations of interferons exist. Interferons act to prevent virus replication.
Interferon is secreted by T-cells to call Natural Killer cells. Interferon as a treatment
modality is best recognized currently in the management of Multiple Sclerosis.
The Triggering of Immune Responses by the Protein Communicators
The Screenplay-The Life and Times of Cytokines
Act 1 – Invasion of the IL-1 Stimulators
An invading organism is engulfed by a macrophage which then couples with a helper
T cell. The macrophage secretes IL-1, which activates the Th and stimulates the
brain to create fever. The fever stimulates immune cell activity.
Act 2 – Turning on the IL-2 and BCGF Machine
The activated Th produces IL-2 which stimulates other Th and killer T cells to grow
and divide. The Th cells secrete a lymphokine called B-cell growth factor (BCGF)
which causes the B cells to multiply.
Act 3 – Antibodies to the Rescue
With an increase in B cells, Th cells produce another lymphokine, B-cell
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differentiation factor (BCDF) which instructs some B cells to stop replicating and to
start producing antibodies.
Act 4 – The Gamma Interferon in You
Th cells also produce gamma interferon (IF) which activates Tk cells and increases
the ability of B cells to produce antibodies. IF also works to keep macrophages at
the site of the infection and facilitates digestion of engulfed cells.
Act 5 – Stop the Train
The lymphokine cascade amplifies the response destroying the enemy. The
reaction stops and the immune system goes into a wait and watch stage.
Additional Factors
A number of other issues factor into the development of chronic inflammation and
deserve a free standing essay but will be covered briefly in this discussion just to bring
some completeness to the understanding of this complex issue.
NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells)
NF-κB is a protein complex that acts as a transcription factor. NF-κB is found in almost
all animal cell types and is involved in cellular responses to stimuli such as stress,
cytokines, free radicals, ultraviolet irradiation, oxidized LDL, and bacterial or viral
antigens. NF-κB plays a key role in regulating the immune response to infection.
Consistent with this role, incorrect regulation of NF-κB has been linked to cancer,
inflammatory and autoimmune diseases, septic shock, viral infection, and improper
immune development. NF-kB activation in the microglia increases neuron death.
When activated, NF-kB induces high levels of TNF-alpha and IL- in the microglia. In
conditions such as multiple sclerosis, there are high levels of activation in the microglia
near the inflammatory plaques.
Cytokine Functions
Microglia
Cytokines
NFkB
ROS and RNS
COX-2
Eicosanoids
Factors that are known to inhibit the activation of NF-kB are listed in the following table.
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CURCUMIN
APIGENIN
QUERCETIN
DHA
ALPHA-TOCOPHEROL
N-BUTYRATE
BAICALEIN
KAEMPFEROL
GREEN TEA
N-ACETYL-L-CYSTEINE
SILYMARIN
SELENIUM
VITAMIN A RETINOL
GINGKO BILOBA
INDOLE-3 CARBINOL
Additionally, Ombega-3 fatty acids reduce inflammation in this NF-kB issue by
decreasing inflammatory cytokines by inhibiting NF-kB directly and by indirect reduction
of arachadonic acid, and prostaglandins 1 and 3.
Eicosanoids
In biochemistry, eicosanoids are signaling molecules made by oxygenation of twentycarbon essential fatty acids, (EFAs). They exert complex control over many bodily
systems, mainly in inflammation or immunity, and as messengers in the central nervous
system. The network of controls that depend upon eicosanoids are among the most
complex in the human body.
Eicosanoids derive from either omega-3 (O-3) or omega-6 (O-6) EFAs. The O-6
eicosanoids are generally pro-inflammatory; O-3's are much less so. The amounts and
balance of these essential fats in a person's diet will affect the body's eicosanoidcontrolled functions, with effects on cardiovascular disease, triglycerides, blood
pressure, and arthritis. Anti-inflammatory drugs such as aspirin and other NSAIDs act
by down-regulating eicosanoid synthesis.
There are four families of eicosanoids—the prostaglandins, prostacyclins, the
thromboxanes and the leukotrienes. For each, there are two or three separate series,
derived either from an O-3 or O-6 EFA. Eicosanoids are considered super hormones as
they control the actions of all other hormones. They represent the quintessential
balance for pro-inflammatory and anti-inflammatory pathways and are very rapid in their
actions with a very short life. Eicosanoids do not circulate in the blood and work in very
low concentrations. A side-by-side comparison of Series 1 and 3 prostaglandins with
Series 2 prostaglandins contrasts their effects within the system.
Omega 3 in Excess
Omega 6 in Excess
Series 1 & 3
Series 2
Increased vasodilation (CAVERJECT) Increased vasoconstriction
Decreased pain
Increased pain
Increased endurance
Decreased endurance
Enhanced immune system
Immune system suppression
Increased oxygen flow
Decreased oxygen flow
Decrease in cellular proliferation
Increases cellular proliferation
Prevents platelet aggregation
Creates platelet aggregation (clotting)
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Dilates airways
Decreases inflammation
Constricts airways
Increases inflammation
Reactive oxygen species (ROS)
Reactive oxygen species are ions or very small molecules that include oxygen ions, free
radicals, and peroxides, both inorganic and organic. They are highly reactive due to the
presence of unpaired valence shell electrons. ROS form as a natural byproduct of the
normal metabolism of oxygen and have important roles in cell signaling. However,
during times of environmental stress ROS levels can increase dramatically, which can
result in significant damage to cell structures.
Cells are normally able to defend themselves against ROS damage through the use of
enzymes such as superoxide dismutases, catalases, glutathione peroxidases and
peroxiredoxins. Small molecule antioxidants such as ascorbic acid (vitamin C),
tocopherol (vitamin E), uric acid, and glutathione also play important roles as cellular
antioxidants. Similarly, polyphenol antioxidants assist in preventing ROS damage by
scavenging free radicals.
Effects of ROS on cell metabolism have been well documented in a variety of species.
These include not only roles in apoptosis (programmed cell death), but also positive
effects such as the induction of host defense genes and mobilization of ion transport
systems. In particular, platelets involved in wound repair and blood homeostasis release
ROS to recruit additional platelets to sites of injury.
Reactive oxygen species are implicated in cellular activity with a variety of inflammatory
responses including cardiovascular disease. Specific examples include stroke and
heart attack.
Reactive nitrogen species (RNS)
Reactive nitrogen species are a family of antimicrobial molecules derived from nitric
oxide (NO·) produced via the enzymatic activity of inducible nitric oxide synthase 2
(NOS2). NOS2 is expressed primarily in macrophages after induction by cytokines and
microbial products, notably interferon-gamma (IFN-γ) and lipopolysaccharide (LPS).
RNS act together with reactive oxygen species (ROS) to damage cells, causing
nitrosative stress. Therefore, these two species are often referred to collectively.
Resolvin E and Resolvin D
Resolvin E(PA) and Resolvin D(PA) are lipid mediators that function to clean up the
debris associated with the inflammatory response. The use of Resolvin is often
associated with regrowth of gums in periodontal disease. J Immunol 2007;179:7021
There is the now timely association of the inflammation of periodontal disease to cardiovascular
health.
Disorders of the Immune (Inflammatory) System
18
Many disorders of the immune system may impact on the patient and subsequently on
their ocular status. Among those are allergy, HIV infection, collagen vascular conditions
(rheumatoid arthritis, systemic lupus erythematosus), pancreatitis creating diabetes, and
variations on Sjogren’s syndrome and collagen vascular conditions with Sjogren’s as a
component. The most recent realization is the impact of the immune system gone awry
on the dementias. In Alzheimer disease there are:
 Elevated IL-1a, IL-2, IL-6, IL-12 and TNF-alpha
 Elevated Inflammatory Eicosanoids PG-D2, PG-E2, and TXB2
 Elevated Complement
 Elevated Matrix Metalloproteinases ( Collagen-destroying enzymes very common
in non-responsive corneal conditions )
 Elevated Adhesion Molecules
Autoimmune disorders, or diseases in which the immune system fails to recognize
certain cells or parts of cells as our own, causes the immune system to attack the very
system it was designed to protect. An example is rheumatoid arthritis (RA) in which
there is pain, swelling, stiffness, and loss of function in the joints. Additionally the victim
suffers fatigue, fever and malaise. RA is characterized primarily by dysregulation of T
cell activity, with cytokines IL-1 and TNF-alpha.
With allergy, the immune system mounts battles against harmless substances such as
pollen, which carry allergens. The allergens in and of themselves pose no threat but
certain individuals have antibodies that mistakenly recognize the allergens as an
enemy. T cells then make matters worse by ordering B cells to produce even more
antibodies. Many allergies appear to be inherited, and as such certain genes may
control our response to certain allergens.
19
The AIDS virus is particularly devastating to the immune system as it destroys the one
lymphocyte most critical to the immune response—the helper T cell. The AIDS virus
may enter the body concealed inside a Th cell from an infected host. In the invaded
victim, the Th immediately detects the foreign Th cell. As the Th cells meet, the virus
slips into the defending Th and disables it. The virus may lay dormant for years waiting
for the opportune time to multiply and spread the invasion. The normal macrophages,
killer T cells and B cells are actually unaware of the spread of the invasion.
With cancer cells it is believed that then antigens on the surface of the cells may change
to alert T cells. Once alerted these T cells start the destruction of the cancer cell. In
early research against cancer, interleukin-2 was used to signal the immune system to
attack cancer cells. The interleukin-2 actually succeeded in creating a veritable army of
killer T-cells.
The basis of inoculation is to use a like version or weakened version of an invader or a
specific antigen to create memory T and B cells to then provide a degree of immunity
against the true invader should it present.
Some of the Ocular Issues Related to Inflammation
 Dysfunctional Tear Syndrome
 Age-Related Macular Degeneration
INFLAMMATION IN ACTION
Br J Ophthalmol June 2009
Higher EPA/DHA intake and reducing glycemic index are associated with
decreased risk for prevention and progression of ARMD. The benefit is blunted
when the AREDs formula is given with the EPA/DHA. Consumption of beta
carotene also increased the risk. For persons with sufficient amounts of AREDS
vitamins in the diet had acceleration of the ARMD process with further AREDS
supplements.
“A diet rich in O3 supplementation without the AREDS supplement might be the
most protective against progression of early ARM if started at the earliest stages
of AMD. While, when combined with the AREDS supplement, it might be most
protective with regard to preventing progression to advanced AMD.”
INFLAMMATION IN ACTION
Swanson, McGwin Optom Vis Sci 2008;85:947
Anti-Inflammatory Drug Use and Age-Related Macular DegenerationThe results of
this study suggest that veterans who had filled a prescription for antiinflammatory medications had a reduced risk of ARMD. Further studies are
needed to confirm this result.
20
INFLAMMATION IN ACTION
AM J CLIN NUTR 2006;83:1494S
Omega 3 Fatty acids, particularly docosahexaenoic acid (DHA), are highly
concentrated in brain and retinal tissue and may prevent or delay the progression
of dementia and AMD. Low dietary intakes and plasma concentrations have been
reported to be associated with dementia, cognitive decline, and AMD risk. …..
unpublished observations from the Framingham Heart Study suggest that > or
=180 mg/d of dietary DHA (approximately 2.7 fish servings/wk) is associated with
an approximately 50% reduction in dementia risk. At least this amount of DHA is
generally found in one commercially available 1-g fish oil capsule given daily.
INFLAMMATION IN ACTION
AM J CLIN NUTR 2001;73:209
Linolenic acid was positively associated with risk of AMD abd DHA had a modest
inverse relation with AMD. Over 4 servings of fish per week was associated with
a 35% lower risk of AMD compared with less than or equal to 3 servings per
month. Total fat intake was positively associated with risk of AMD and a high
intake of fish may reduce the risk of AMD.
INFLAMMATION IN ACTION
AM J CLIN NUTR 2008;88:398
Eating oily fish at least once per week compared to less than once per week was
associated with a halving of the odds ratio for neovascular ARMD.
 Glaucoma
INFLAMMATION IN ACTION
(Invest Ophthalmol 1996;37:2744, J Glaucoma 1996;5:427)
Altering free radicals with steroids, which paradoxically could increase
intraocular pressure, may block lipid peroxidation. Tirilazad mesylate, an
aminosteroid may also be able to block lipid peroxidation in a similar manner.
This is primarily achieved through suppression of inflammation.
INFLAMMATION IN ACTION
21
(Circulation 2005;112:900, J Glaucoma 2005;14:384, Circ Res 2004;95:877, Invest
Ophthalmol Vis Sci 2002;43:2704, J Glaucoma 2002;11:259, J Glaucoma
1997;6:83, Br J Ophthalmol 2005;89:60, Invest Ophthalmol Vis Sci 2003;44:2565)
C-reactive protein (CRP) elevation is also associated with CSVD indicating an
inflammatory process, and the elevated CRP levels are also found in NTG
patients. The CRP increases endothelin which has been implicated in the
proliferation of astrocytes in the nerve head and changes in the trabecular
meshwork and has been found to be elevated in glaucoma and NTG after
exposure to cold temperatures.
INFLAMMATION IN ACTION
(Cell Mol Neurobiol 2001;21:617)
Immune System influences including antibodies generated by B-cells within the
rubric of the general inflammatory process lead to cell death in glaucoma.
Protection also occurs through the immune system pointing to the importance of
proper modulation of the immune system.
INFLAMMATION IN ACTION
(Cell Mol Neurobiol 2001;21:617, J Neurosci 2000;20:6421, J Neuroimmunol
2000;106:189, Nat Med 1999;5:49, Am J Ophthalmol 2006;141:1105, Surv
Ophthalmol 2001;45:S256, Invest Ophthalmol Vis Sci 2003;44:407, Proc Natl Acad
Sci USA 2001;98:3398, Proc Natl Acad Sci USA 2000;97:7446)
Autoimmunity is at the root of most disorders and is defined as an attack on the
host cell by activated T cells. It has actually been shown that survival of RGCs
after optic nerve injury is facilitated by the autoimmune response via activated T
cells. This response can either be by active immunization with a protein or by
transfer of activated T cells.
INFLAMMATION IN ACTION
(Mol Med 1997;3:765, Stroke 1994;25:1481, Stroke 1997;28:1233, Invest
Ophthalmol Vis Sci 2001;42:1787)
TNF- alpha is a pro-inflammatory cytokine that is present during excitotoxic and
ischemic brain injury. Among other functions, it binds to the death receptor and
can induce caspase components of the mitochondrial cell death pathway. TNFalpha has been implicated as a mediator in RGC death.
(Exp Eye Res 2006;83:1335, Exp Eye Res 2006;83:1246)
TNF- α inhibitors (GLC756) are being investigated for the treatment of glaucoma.
 Conjunctivitis
22
 Corneal Ulcers
 Anterior and Posterior Uveitis
 Scleritis
 Episcleritis
 Toxoplasmosis Reactivation
 Histoplasmosis
MEASURES OF INFLAMMATORY ACTIVITY
The issue of testing for immune system disorders is very complex but some knowledge
of the testing protocol is imperative. Following is a primer for this understanding.
IL-6 and Other Inflammatory Markers (CYTOKINE PANEL - IL1b, IL6, IL8, TNF
alpha)
Interleukin-1 beta (IL-1b)
This test is used to identify elevated levels of Interleukin-1 beta. IL-1b is a cytokine
produced principally by mononuclear phagocytes but also by various other cells types
including keratinocytes, epithelium and cells of the CNS. Elevated levels of
Interleukin-1 beta have been implicated in sepsis, cachexia, rheumatoid arthritis,
chronic myelogenous leukemia, asthma, psoriasis, inflammatory bowel disease,
anorexia, AIDS, and graft-versus-host disease associated with bone marrow
transplants. IL-1B is one of the key mediators of immunobiological responses to
physical stress, a pilot study showed that higher levels were associated with
anxiety/panic disorder. Higher than normal levels have also been associated with a
significant increased risk of myocardial infarction independent of Cardio-CRP levels.
Interleukin-6 (IL-6) This test is used to identify elevated levels of Interleukin-6. IL-6 is a cytokine produced
by many different cells including monocytes/macrophages, fibroblasts, endothelial
cells, keratinocytes, mast cells, T cells and many tumor cell lines. Elevated IL-6 serum
or plasma levels may occur in different conditions including sepsis, autoimmune
diseases, lymphomas, AIDS, alcoholic liver disease, tumor development, Alzheimer’s
disease, and in c with infections or transplant rejection. Elevated levels of IL-6 may be
associated with an increased risk of heart attack, and stroke.
Interleukin-8 (IL-8)
This test is used to identify elevated levels of Interleukin-8. IL-8 is produced by
stimulated monocytes, macrophages, fibroblasts, endothelial cells, keratinocytes,
melanocytes, hepatocytes, chondrocytes, and a number of tumor cell lines. In many
types of cells the synthesis of IL8 is strongly stimulated by IL1 and TNF-alpha.
23
Elevated concentrations are observed in psoriasis rheumatoid arthritis, chronic
polyarthritis, tumor development and Hepatitis C.
Tumor Necrosis Factor Alpha (TNF-alpha)
This test is used to identify elevated levels of Tumor necrosis factor alpha. A variety of
cells are shown to produce TNF-alpha. TNF-alpha is a growth factor for fibroblasts
and stimulates the synthesis of collagenase and prostaglandin E2. Bone resorption
can be induced by TNF-alpha because it activates osteoclasts. TNF-alpha enhances
the proliferation of T cells after stimulation with IL-2. In the absence of IL-2, TNFalpha induces the proliferation and differentiation of beta cells. TNF-alpha levels may
be elevated in sepsis, cachexia, AIDS, Hepatitis C, transplant rejection, various
infectious and autoimmune diseases.
C-Reactive Protein
C-Reactive protein (CRP) is a molecule produced by the liver in response to an
inflammatory signal. During an acute illness, like a severe bacterial infection, levels of
CRP quickly rise from less than 10 mg/L to 1,000 mg/L or more.
Healthy middle-aged men with the highest CRP levels were three times as likely to
suffer a heart attack in the next six years as were those with the lowest CRP levels.
Having a CRP reading of 3.0 mg/L or higher can triple your risk of heart disease. The
danger seems even greater in women than in men.
INFLAMMATION IN ACTION
NUTRITION 2006 22:441
Higher levels of serum antioxidants vitamin C and lutein/zeaxanthin and higher
fish intake were associated with lower serum CRP levels, whereas serum vitamin
E, smoking, and increased body mass index were associated with increased CRP.
Serum vitamin E, serum alpha-carotene, and dietary intake of antioxidants and
vitamin B6 were associated with lower levels of plasma homocysteine ( HCY ),
whereas hypertension was associated with increased HCY.
C-reactive protein and HCY levels are related to traditional dietary and behavioral
factors associated with age-related macular degeneration.
Erythrocyte Sedimentation Rate
The Erythrocyte Sedimentation Rate is a nonspecific test used to detect illness
associated with acute and chronic infection, autoimmune disorders, inflammation
(collagen vascular diseases), advanced neoplasm, and tissue necrosis or
infarction. ESR is the rate at which red blood cells precipitate in a period of 1
hour. Elevations in fibrinogen, alpha- and beta-globulins (acute phase
reactants), and immunoglobulins increase the sedimentation rate of red cells
24
through plasma. The test is important in the detection of temporal arteritis, as
well as its management.
The widely used rule for calculating normal maximum ESR values in adults (98%
confidence limit) is given by a formula devised in 1983:
ESR (mm/hr) = Age + 10 if Female
2
ESR should, however, be evaluated in regard to the general health status of the patient
and is not a representation of an absolute. The combination of ESR and CRP result in
an improved sensitivity and specificity for both tests.
Rheumatoid Panel Summary
Rheumatoid Factor
Antinuclear antibodies are auto-antibodies that react against the nuclei of the body's
own cells when they are mistaken for foreign invaders. Rheumatoid factor (RF, Latex)
measures an abnormal antibody called rheumatoid factor in the blood. The majority of
people with rheumatoid arthritis have a large amount of rheumatoid factor in their blood.
It is important to note that having a positive rheumatoid factor will assist in the
diagnosis, but the test alone is not conclusive.
Antinuclear Antibody
The antinuclear antibody test (ANA) detects a group of auto-antibodies that are found in
most people with lupus and scleroderma and in a few people with rheumatoid arthritis.
These auto-antibodies react with antigens in the nuclei of cells. Specific antinuclear
antibody tests are helpful in the diagnosis of certain rheumatic diseases that involve
abnormalities in the immune system.
Following are studies specific to disease processes that often manifest ocular signs and
symptoms:
Systemic Lupus Erythematosus (SLE); anti-dsDNA, anti-Sm, anti-Ro/SS-A,
and anti-histone tests help confirm the diagnosis. Complement tests involve the
reaction of antibodies with antigens. These tests usually are reserved for
diagnosing or monitoring people with active lupus. Those people with lupus
frequently have lower-than-normal amounts of complement, especially if the
kidneys are affected.
Scleroderma; anti-Scl-70 test helps confirm the diagnosis.
Polymyositis ; anti-Jo-l and anti-PM-l tests help confirm the diagnosis.
25
Sjogren's Syndrome ; anti-Ro/SS-A and anti-La/SS-B tests help confirm the
diagnosis.
Managing  Inflammation
There are a number of methods of managing inflammation. The issue continues to be
managing “bad” inflammation without negatively influencing “good” inflammation. The
balance or modulation of the immune system continues to be the most important
aspect of the entire issue.
Aspirin
Many agents are available to fight the inflammatory process both within the body and
within the eye. Use of aspirin to minimize the risk of cardiovascular disease has been
recognized for some time. The effect of aspirin has been mistakenly linked to the
thinning of the blood as the reason for risk reduction. In actual fact the reason is more
intimately associated to the reduction of the inflammatory process that precipitates
plaque formation on the vessels. Unfortunately aspirin as well as some of the other
COX inhibitors block both the beneficial and harmful arms of the inflammatory cascade
because they act very early in the process. The ultimate inflammatory modulator would
minimize harmful inflammatory potentiators while enhancing beneficial portions of the
inflammatory cascade.
Topical and Oral Steroids, Restasis® and Lid Scrubs
Localized management of ocular surface, lid disease, intraocular, and retinal-choroidal
inflammatory disorders can be attained through the utilization of topical, injectable and
oral steroids. There is no doubt that these agents must be used at times to get
inflammation under control but even the soft steroids carry the risk of complications
when used over a prolonged period of time. Steroids should always be used while
mentally chanting the mantra “quick in, hit it hard, then get out.” After steroids control
the process, other agents such as methotrexate may be employed to control the
inflammation over a prolonged period of time. Methotrexate acts by inhibiting the
metabolism of folic acid. Lower doses of methotrexate have been shown to be very
effective for the management of rheumatoid arthritis, Crohn's disease, and psoriasis. In
these cases inhibition of dihydrofolate reductase (DHFR) is not thought to be the main
mechanism, but rather the inhibition of enzymes involved in purine metabolism, leading
to accumulation of adenosine, or the inhibition of T cell activation and suppression of
intercellular adhesion molecule expression by T cells.
Massage and lid cleansing are well-established modalities of treatment of anterior
segment disorders. The use of Restasis® is also recognized as an effective method of
immunomodulation of anterior segment inflammatory disorders especially when
combined with other methods of management of these chronic disorders.
26
Azasite
AzaSite® (azithromycin ophthalmic solution) is a 1% sterile aqueous topical ophthalmic
solution of azithromycin formulated in DuraSite® functioning as a macrolide antibiotic.
The application is for the treatment of bacterial conjunctivitis with high and prolonged
tissue concentrations. Azasite also displays anti-inflammatory activity and suppresses
matrix metalloproteinases (MMPs) with activities similar to doxycycline. Topically
applied Azasite can be a very effective adjunct to therapy for inflammatory processes of
the lids and corneal surface.
Oral Cyclines
Oral cyclines are well known to have strong anti-inflammatory activities. The antibiotic
effect is minimal especially at lower doses. Oral cyclines are also very effective matrix
metalloproteinases (MMPs) inhibitors which in effect minimize the destruction of
collagen throughout the body. This MMP suppressive activity is critical in the inhibition
of destruction as related to multiple ocular disorders. Standard dosages range from
20mg to 200mg per day but potential side effects limit long-term application. Lower
dosages are often used in the long-term management of periodontal disease and do not
have the potential negative implications.
The Utilization of Omega 3 and Omega 6 Fatty Acids
A look at a simplification of the issue as related to Omega 3 and Omega 6 fatty acids
brings the entire issue into perspective. A number of sites along the pathway may be
controlled by anti-inflammatory agents. Aspirin can block the entire pathway but in
doing so it blocks PGE-1 which is critical in the manufacture of fluids within the
gastrointestinal tract. By altering the fluid production, the GI tract is set up to potentially
develop ulcers. Every action and every blockage of that action has a subsequent
reaction. COX Inhibitors may be used to block the inflammatory activity of the proinflammatory agents. Unfortunately indiscriminate blockage of COX may result in
serious side effects. COX exists on both sides of the inflammatory chain and COX-1
precipitates VASOCONSTRICTION AND THROMBOSIS while COX-2 precipitates
VASODILATION AND ANTITHROMBOSIS. Should COX-2 be blocked, COX-1
dominates allowing for vasoconstriction and thrombosis, both famed in the genesis of
myocardial infarct and cerebrovascular accident. Balance, again, is the key.
27
The Omega Pathways
PROINFLAMMATORY
ANTIINFLAMMATORY
WESTERN DIET
HIGH OMEGA 6
MED DIET
HIGH OMEGA 3
IMMUNE SYSTEM TRIGGERS
CELL MEMBRANE
CELL MEMBRANE
PHOSPHOLIPID A2
PHOSPHOLIPID A2
THESE ARE INHIBITED TOTALLY
BY STEROIDS BLOCKING ALL
FATTY ACID RELEASE AND RESULTS
IN NO IMMUNE SYSTEM RESPONSE
AA AA AA
LOX COX COX
EPA/DHA EPA
NONSELECTIVELY BLOCKED
LOX
GLA
COX
COX
PGE-3
PGE-1
BY ASPIRIN
LTB-4 TXA-2 PGE-2
LTB-5
Also the lower in the pathway the more effective the intervention as the metabolic
activity to achieve the end product is much more effective. This is illustrated by the fact
that to get to effective EPA and DHA levels flaxseed oil must undergo additional
metabolic events to achieve the same end as the triglyceride backbone omega 3 which
provides the heightened efficacy of the EPA and DHA. Note also in the following
pathway that EPA even functions in the Omega 6 pathway by blocking the conversion of
DGLA to inflammatory arachadonic acid. The overall net effect of dominant Omega 3s
is anti-inflammation.
28
The Metabolic Pathways of Omega 3 and Omega 6 Essential
Free Fatty Acids As Related to the Inflammatory Process
OMEGA 6 FFAs
OMEGA 3 FFAs
Linoleic Acid
Alpha-Linolenic Acid
(Flaxseed Oil)
Gamma-Linolenic Acid (GLA)
(Evening Primrose, Black Current Seed)
Steridonic Acid
Dihomo-Gamma-Linolenic Acid (DGLA)
Elcosatraenoic Acid
PGE1
(EPA Blocks Conversion of DGLA EPA
DHA
(anti-inflammatory) to AA Which is Pro-Inflammatory)
(FISH OIL)
Arachidonic Acid (AA), PGE2, LTB4, TXa2 PGE3
LTB5
(All Pro-Inflammatory)
(Anti-Inflammatory)
Obesity, Weight Control and Exercise
In the gestalt of understanding Inflammation, the topics of obesity, weight control and
exercise are critical topics.
29
INFLAMMATION IN ACTION
(JAMA.2000; 283: 2235, JAMA. 2003;290:1709)
Obesity is associated with:
Elevated CRP
Elevated ESR
Elevated IL-6
Elevated TNF-alpha
To understand why obesity is a manifestation of chronic inflammation the following
figures illustrate the platform. An obese person can actually decrease caloric
consumption and may be unable to effectively lose weight because of the effects of the
inflammatory system. Fat naturally attracts macrophages which comprise 40 to 50% of
the cells in adipose tissue. Fat cells sequester arachidonic acid (AA) the building block
of all pro-inflammatory eicosanoids. With the buildup of AA there is the production of
pro-inflammatory eicosanoids which generate the buildup of the cytokines (including IL6 and TNF-alpha) within the adipocytes. While the eicosanoids cannot enter the
circulatory system, the cytokines do so stimulating a cascade of additional inflammatory
responses throughout the body. This is all done through the action of adipokines which
are cytokine like materials produced in the process. Leptin is a critical adipokine, which
exists to suppress hunger. The brain senses satiation via Leptin.
ADIPOKINES ARE CYTOKINE LIKE MATERIALS PRODUCED BY FAT
CELLS and ARE MEDIATORS OF INFLAMMATION
Fat Attracts Macrophages (40-50% of cells in adipose tissue)
IL-6
Inflammatory Response
Leptin
TNF-alpha
Resistin
When severe, inflammation ultimately gives destruction of fat
resulting in the paradox of marked weight loss
Understanding the action of the adipokines in the presence of obesity becomes a bit
more complex. This family in a 50 advertisement illustrates the old way of thinking
30
about health and nutrition. If you are obese you should be able to lose weight just by
not consuming as much food. An understanding of the chemistry of the inflammatory
system illustrates the error of this thought process. What happens in the Leptin
processing really illustrates the reality of the importance of inflammation.
Leptin is an adipokine that suppresses hunger but what happens to Leptin in the obese
individual overwhelmed by inflammation? Within the framework of inflammation are the
molecules Suppressors of Cytokine Signaling (SOCS-1 and SOCS-3). These
molecules reduce inflammation and obese individuals naturally have elevated SOCS
levels because of the chronicity of inflammation associated with excessive fat. These
SOCS, while beneficially reducing inflammation, also trigger insulin resistance and
interfere with Leptin signaling to suppress hunger. So while attempting to modulate
inflammation the SOCS also result in insulin resistance and a sluggish metabolism. The
effect of Leptin is thus negated resulting in no sense of satiation.
31
LEPTIN IS AN ADIPOKINE THAT SUPPRESSES HUNGER
WHAT HAPPENS IN OBESITY?
SOCS-1
SOCS-3
(SUPPRESSORS
OF CYTOKINE
SIGNALING)
MOLECULES INVOLVED IN
REDUCING INFLAMMATION
NEGATIVE
FEEDBACK
LOOP
OBESE INDIVIDUALS HAVE
CHRONIC INFLAMMATION AND
ELEVATED SOCS-1 AND SOCS-3
ALSO
TRIGGER
INSULIN
RESISTANCE
INTERFERENCE WITH LEPTIN
SIGNALING TO SUPPRESS
HUNGER CREATING SLUGGISH
METABOLISM
This action then impacts on insulin metabolism especially as it relates to skeletal muscle
leading to the metabolic syndrome problem.
INFLAMMATION IN ACTION
THE IMPORTANCE OF IL-6 BEHAVIOR IN OBESTIY
IL-6 is a strong marker of inflammation. It is considered an ALL CAUSE
MORTALITY PREDICTOR along with CRP, and other inflammatory markers.
Blood Purif 2008;26:204.
The paradox is that an ACUTE RISE OF IL-6 ASSOCIATED WITH EXERCISE
(ACTION OF THE SKELETAL MUSCLE) IS PROTECTIVE IN NATURE. Skeletal
muscle is the body’s largest endocrine organ and is the principal site of
insulin resistance. It is important that during exercise skeletal muscle needs
to increase uptake of glucose and fatty acids to generate ATP to refill
glycogen levels. With contraction skeletal muscle expresses and releases
myokines (cytokines) influencing both metabolism and inflammation.
Contraction of Type 1 muscle fibers increases release of IL-6, which
influences insulin sensitivity, lipolysis and increased oxidation. IL-6 is the
energy sensor in the skeletal muscle. Contraction of Type 2 muscle fibers
stimulates production of both TNF-alpha and IL-18 which influences insulin
resistance, cachexia and apoptosis. As such, exercise has a tremendous
influence on the behavior of the inflammatory response. J Leuko Biol
2005;78:819 One of the latest studies points to the fact that increased fitness
is associated with 50% to 70% reductions in all-cause mortality. (Circulation
2008;10:1161)
32
INSULIN RESISTANCE
INFLAMMATION BLOCKS INSULIN AT THE SKELETAL MUSCLE
POOR UTILIZATION OF GLUCOSE CONVERSION IN MUSCLE
INCREASED INSULIN BY PANCREAS
INCREASED
INFLAMMATION
INCREASED
CORTISOL BY
ADRENALS
INCR ABDOMINAL OBESITY
FLUID RETENTION
MUSCLE WEAKNESS
MEMORY LOSS
HTN
INCR BLOOD GLUCOSE
The metabolic syndrome has the following characteristics and is intimately related to
insulin resistance:
Characteristics of the Metabolic Syndrome
1. Abdominal obesity
2. Atherogenic dyslipidemia
3. Elevated Blood Pressure
4. High insulin levels-over 10
a. Raises fats into cells
b. Promotes fat storage
c. Stimulates arterial smooth muscle cells
d. Promotes production of bad types of eicosanoid
e. Series two ECs are bad-glucagon is a strong inhibitor of EC 2 pathway
5. Promotes retention of fluids by kidneys
Glucagon is the anti-insulin and is increased by high proteins low carbohydrates
6. High levels of inflammatory mediators
To summarize the effect of exercise on obesity and inflammation:
1. Chronic systemic inflammation accompanies and contributes to chronic systemic
33
and ocular diseases such as diabetes, cardiovascular disease, dry eye, and agerelated macular disease
2. Exercise of the skeletal muscles induce an anti-inflammatory response through
the release of IL-6 which acts in a paradoxical manner on the immune system
and modulates insulin uptake and lipid metabolism
3. Myokines ( muscular cytokines ) mediate the inflammatory process and assist in
the fight of chronic inflammation
4. Fat cells are factories producing inflammatory elements and burning calories
shrinks those factories.
The Burden of Inflammation
Morbidity
Obesity
Smoking
Infection
High Fat Intake
Injury
Increased Physical Activity
INFLAMMATION
Further down the cascade is the development of issues associated with the chronicity of
inflammation such as osteoarthritis.
THE ASSOCIATION OF OBESITY TO OSTEOARTHRITIS
OBESITY
EXCESS ADIPOKINE (LEPTIN) IN JOINT FLUID PRODUCED BY
EXCESS FAT CELLS
STIMULATES TNF-BETA TO DAMPEN INFLAMMATION
TNF-BETA STIMULATES BONE GROWTH IN JOINTS
OVERGROWTH OF BONE = OSTEOARTHRITIS
34
The Anti-Inflammatory Diet
The importance of weight control and diet in the management of chronic inflammation.
Is critical. The J Am Coll Cardiol 2008;51:249 recommends that an anti-inflammatory
diet should be considered for the primary and secondary prevention of coronary artery
disease and diabetes. Characteristics of their recommendations follow:
 The glycemic index of a food is defined as the incremental increase in the area
under the postprandial glucose curve after ingestion of 50 g of a specific amount of
food vs that associated with 50 g of oral glucose. Ideal carbohydrates with a low
glycemic index include green leafy vegetables such as broccoli and spinach and
fruits such as grapefruits and cherries. Select high-fiber carbohydrates with low
glycemic index, including vegetables, fruits, whole grains, legumes, and nuts.
 Excess intake of processed carbohydrates leads to a vicious cycle of transient
spikes in blood glucose levels, increased insulin production, and reactive
hypoglycemia. Avoid highly processed foods and beverages, particularly those
containing sugar, high-fructose corn syrup, white flour, or trans fats.
 Berries, dark chocolate, red wine, tea, and pomegranates reduce postprandial
oxidant stress and inflammation. Cacao beans contain a subclass of flavonoids
which have been reported to augment eNOS and thereby NO. This improves
endothelium-dependent vaso-relaxation. (J Nutr 2000;130:2105S) One study
showed that one square of dark chocolate was 6.3 g and represented only 30 kcal
per day but previous studies have shown that 100 g of dark chocolate lowers BP by
12/8 mm Hg but with the risk of increased caloric intake. (JAMA. 2007;298:49)
 Coffee contains antioxidants and can improve insulin sensitivity. Consumption of
black tea reduces platelet activation and plasma levels of C-reactive protein.
However, previous research has not demonstrated a consistent reduction in the risk
for stroke associated with coffee or tea consumption. One study suggests that
higher levels of coffee and tea consumption can reduce the risk for cerebral
infarction among male smokers but not rates of intracranial hemorrhage. (Stroke
2008;39:1681)
 When paired with a high-glycemic-index meal, cinnamon slows gastric emptying
and reduces postprandial glucose excursion.
 Nuts also slow gastric emptying and can reduce the impact of high-glycemic-index
carbohydrates by as much as half. Nuts also reduce postprandial oxidative protein
damage, and consumption of nuts at least 5 times weekly can reduced the risks for
coronary artery disease and diabetes by 20% to 50%. Eat approximately 1 handful
of nuts daily (using a closed fist), consumed with vegetables, grains, berries, or
other fruits.
 Vinegar can reduce postprandial glycemia and promotes satiety. Eat salad daily,
consisting of leafy greens with dressing of vinegar and virgin olive oil. Lean
protein reduces postprandial glucose excursion and improves satiety. Such protein
35
includes egg whites, game meat, skinless poultry breast meat, and whey
protein or other nonfat dairy protein. At all 3 meals, consume lean protein.
 Drinking 0.5 to 1 alcoholic drink per day for women and 1 to 2 alcoholic drinks per
day for men can reduce cardiovascular risk, and 1 to 2 drinks before a meal can
reduce postprandial glucose and insulin levels. However, higher levels of drinking
can impair glucose metabolism.
 Exercise acutely lowers glucose and triglyceride levels in a dose-dependent fashion.
Perform physical activity for at least 30 minutes or more daily, of at least
moderate intensity.
 Maintain normal weight and avoid overweight or obesity. Waist circumference should
be less than one half of height in inches.
INFLAMMATION IN ACTION
J Nutr Elder 2004;24:1, Am J Clin Nutr 2007;86:1210 , Am J Clin Nutr 2007;86:180
One study illustrates the impact of nutrition and glycemic index on the genesis of
age-related macular degeneration (ARMD). There is one report that a high
consumption of corn bread indicated a significant association with central vision
loss in ARMD. Another report found cross-sectional studies indicate that diets
that provide a higher dietary glycemic index (dGI) are associated with a greater
risk of age-related macular degeneration (ARMD). Persons at risk of AMD
progression, especially those at high risk of advanced AMD, may benefit from
consuming a smaller amount of refined carbohydrates. The association between
dietary glycemic index (dGI) and AMD from the AREDS cross-sectional analysis
at baseline suggests that a reduction in the dGI, a modifiable risk factor, may
provide a means of diminishing the risk of AMD.
The Impact of Nutrition on Health
While controversial and denied by many health care professional, nutrition and lifestyle
play a major role in maintenance of health. The habit of smoking with its potential
negative impact on health is among the most obvious issues to avoid. Other facts are
often overlooked regarding the impact of nutrition on health, and can be illuminated by
looking at results of poor nutrition. Historical examples of nutritional epidemics include:
Scurvy
Scurvy was a nutritional epidemic caused by the lack of vitamin C. The cure was citrus
fruits included on sea voyages. Symptoms included:
 Nausea
 Ease of bruising
 Tiredness
 Swollen and bleeding gums
 Muscle and joint pain
 Loosening of teeth
36
 Wounds healing poorly
 Irritability & Anxiety
 Old fractures separating
 Sleep disorders
 Dry skin and hair
Neural Tube Defects
Neural tube defects including Spina Bifida, and Anacephaly were of epidemic
proportions until the inclusion of Folic Acid in the diets of pregnant women. Restoration
of Folic Acid in the diet of pregnant women resulted in a 70% reduction of Spina Bifida
from 2004 to 2006.
Hyperhomocysteinemia
Hyperhomocysteinemia (elevated homocysteine levels) continues to be a nutritional
epidemic implicated in a number of systemic and ocular conditions. Those include:
Systemic
1. Increased cardiovascular morbidity and mortality
a. 15-30% of patients with premature vascular disease
b. 25% of non-diabetic patients under age 55 with heart attacks or stroke
have hyperhomocysteinemia versus 5% of those without
2. Increased risk of cancer deaths
3. Increasing the risk of Alzheimer’s disease
4. Chronic gastrointestinal disease – irritative bowel disease
5. Collagen disorders and osteoporosis
6. Chronic renal insufficiency
7. Relationship to depression
Ocular
1. Primary Open Angle Glaucoma
2. Pseudoexfoliation and pseudoexfoliative glaucoma and risk of thromboembolic
events in these patients
3. Non-arteritic ischemic optic neuropathy especially in younger patients
4. Neovascular glaucoma in patients with diabetes
5. Exudative age-related macular degeneration
6. Retinal vaso-occlusive disease independent of other risk factors especially in
younger patients
7. Retinal emboli
8. Behcet’s disease
9. Diabetic retinopathy, especially macular edema
If you do nothing else but recommend foods or supplements with not more than 400 to
1000 mcg of folic acid per day, 10 to 50 mg of vitamin B6, and 50-300 mcg of vitamin
B12 per day, you may impact soundly on ocular and systemic morbidity and mortality in
your patients.
37
Beri Beri
Beri beri is a nervous system issue created by a deficiency of thiamin in the diet.
Symptoms include weight loss, impaired sensory perception, fatigue, lethargy, with
complications involving many systems that could lead to death. The disease is most
common in persons whose diet consists mainly of polished white rice, alcoholics, and
patients with bariatric procedures. Supplementation with thiamin results in rapid
resolution of symptoms.
Vitamin A Deficiency
Up to 500,000 malnourished children go blind each year worldwide from a deficiency of
Vitamin A. Approximately half of those die within a year of becoming blind. It is
estimated that 13.8 million children worldwide have some degree of visual loss related
to Vitamin A deficiency. Vitamin A is also critical in the maintenance of the immune
system and deficiency increases the risk of many acquired disorders. This disease
could be eliminated by simple supplementation and/or food fortification.
Rickets
Vitamin D deficiency in infants and children results in rickets with the growth plate
enlarging without the support of mineralization of the long bones. This results in bowing
of the legs. Sufficient vitamin D prevents rickets in children and osteomalacia in adults
and, together with calcium, vitamin D helps protect older adults from osteoporosis.
The Impact of Essential Fatty Acids
Essential fatty acids
Recommendations
Circulation. 2002;106:2747
The American Heart Association recommends that people without documented
CHD eat a variety of fish (preferably oily) at least twice weekly, in addition to
consuming oils and foods rich in ALA. 1 gram/DAY EPA + DHA is recommended
but 3-4 gram/DAY WITH HIGH TRIGLYCERIDE ISSUES-LOWERS 45%.
All fats are not bad but up to 83% of Americans are deficient in Omega 3 fatty acids.
The critical component of all of this is the realization that the body requires EPA and
DHA and has absolutely no requirement for trans fats in the diet. Diets heavy in Omega
6 result in increased morbidity and mortality. Omega 6 must be appropriately balanced
by Omega 3 to sustain health. Fats that stay solid at room temperature are considered
saturated fats while those that remain liquid at room temperature are considered
unsaturated. Saturated fats are more closely connected to the genesis of disease and
appear to be ubiquitous in the Fast Food Diets. An illustration of the differences is
simplified as follows:
38
Omega 3-Anti-Inflammatory
Omega 6-Pro-Inflammatory
Alphalinolenic Acid (ALA)
Linoleic Acid (LA)
Plants, Tree Nuts
Vegetable Oils, Saturated Fats
Eicosapentaenoic Acid (EPA)
Gamma-Linolenic Acid (GLA)
Fish
Evening Primrose, Borage, Black Currant
Docosahexanoic Acid (DHA)
Arachidonic Acid (ARA)
Fish
Vegetable Oils, Saturated Fats
Alpha-linolenic acid (ALA), an omega-3 fatty acid, and linoleic acid (LA), an omega-6
fatty acid, are considered essential fatty acids because they cannot be synthesized by
humans. The long-chain omega-6 fatty acid, arachidonic acid (AA) can be synthesized
from LA. The long-chain omega-3 fatty acids, eicosapentaenoic acid, the eye food
(EPA) and docosahexaenoic acid, the brain food (DHA) can be synthesized from ALA,
but EPA and DHA synthesis may be insufficient under certain conditions as ALA
converts poorly to EPA and DHA. In fact a high intake of ALA has been associated
with a 49 % increased risk of ARMD. Arch Ophthalmol 2008;126:826.
Typical Western diets tend to be much higher in omega-6 fatty acids than omega-3 fatty
acids, which are polyunsaturated fatty acids, and proper proportions are usually offered
as ratios. The best sources of Omega 3s are cold-water fish, walnuts, dark green leafy
vegetables, beans, fish oils and flaxseed oil. In contrast Omega 6 essential fatty acids
are over-abundant in the diet, Omega 3 to Omega 6 being 1:10, with the ideal Omega 3
to Omega 6 ratio being 1:1 or 1:2. The aberrancy is largely the result of increased
consumption of vegetable oil. The disproportion that is created allows for an imbalance
in developmental aspects of tissues as well as fostering the proliferation of more “bad”
than “good” prostaglandins in the inflammatory cascade.
Omega-6 and omega-3 polyunsaturated fatty acids are important structural components
of cell membranes. The phospholipids affect cell membrane properties such as fluidity,
flexibility, permeability and the activity of membrane bound enzymes. DHA is found in
very high concentrations in the cell membranes of the retina, which conserves and
recycles DHA even when omega-3 fatty acid intake is low. Recent research indicates
that DHA plays an important role in the regeneration of the visual pigment rhodopsin.
The phospholipids within the gray matter of the brain contain high proportions of DHA
and AA, suggesting importance in central nervous system function. Another study
showed that eating fish oil (oily fish including mackerel, tuna, salmon, sardines
and herring) at least once a week is linked to a reduced risk for neovascular agerelated macular degeneration. This is being further investigated in the ongoing
AREDSS2 study. (Am J Clin Nutr. 2008;88:398) Most studies point to the importance
of balance of essential free fatty acids in ocular and neurological development.
Two new studies have shown that Omega-3 fatty-acid supplementation improves
morbidity and mortality in symptomatic heart-failure patients, while statins failed
to have any beneficial effect in the same group of patients. (Lancet 2008; DOI:
39
10.1016/S0140-6736(08)61241, Lancet 2008; DOI: 10.1016/S0140-6736(08)61239)
One study indicates that increasing intakes of long-chain omega-3 fatty acids (EPA and
DHA) can decrease the risk of cardiovascular disease by 1) preventing arrhythmias that
can lead to sudden cardiac death, 2) decreasing the risk of thrombosis that can lead to
MI or stroke, 3) decreasing serum triglyceride levels, 4) slowing the growth of
atherosclerotic plaque, 5) improving vascular endothelial function, 6) lowering blood
pressure slightly and 7) decreasing inflammation. Many reports show men who eat fish
at least once weekly have lower mortality from CHD than men who do not eat fish. One
such study followed 1822 men for 30 years and found that mortality from CHD was 38%
lower in men who consumed an average of at least 35 g (1.2 oz) of fish daily than in
men who did not eat fish, while mortality from MI was 67% lower. In the Nurses’ Health
Study, following over 84,000 women for 16 years, CHD mortality was 29-34% lower in
women who ate fish at least once a week compared to women who ate fish less than
once a month. Epidemiological studies suggest that regular fish consumption is
inversely associated with the risk of sudden cardiac death. Another prospective study
that followed more than 45,000 men for 14 years found that the risk of sudden cardiac
death was about 40-50% lower in those who consumed an average of at least 250
mg/day of dietary EPA + DHA, the equivalent of 1-2 oily fish meals weekly, than those
who consumed less than 250 mg/day. When referencing the impact on the incidence of
stroke, two large prospective studies found that increased fish and omega-3 fatty acid
intakes were associated with significantly lower risks of ischemic stroke, but not
hemorrhagic stroke. In a study that followed more than 79,000 women for 14 years,
those who ate fish at least twice weekly had a risk of thrombotic (ischemic) stroke that
was 52% lower than those who ate fish less than once monthly. Likewise another study
that followed more than 43,000 men for 12 years, those who ate fish at least once
monthly had a risk of ischemic stroke that was 43% lower than those who ate fish less
than once monthly. The triglyceride-lowering effects of EPA and DHA increase with
dose, but clinically meaningful reductions in serum triglyceride concentrations have
been demonstrated at larger doses of 2 g/day of EPA + DHA and triglycerides are
especially important in patients with diabetes.
Increasing EPA and DHA intake may be beneficial to individuals with diabetes,
especially those with elevated serum triglycerides while randomized controlled trials
have found that fish oil supplementation decreases joint tenderness and reduces the
requirement for anti-inflammatory medication in rheumatoid arthritis patients. The
American Diabetes Association recommends that diabetic individuals increase omega-3
fatty acid consumption by consuming two to three 3-oz servings of fish weekly. There is
also an association with the control of inflammatory bowel disease, ulcerative colitis and
Crohn’s disease. One recent study also suggests that there may be a beneficial effect
of low-dose dietary polyunsaturated free fatty acids on vascular function and disease
activity in SLE.
Although limited preliminary data suggests that omega-3 fatty acid supplementation
may be beneficial in the therapy of depression, bipolar disorder and schizophrenia,
larger controlled clinical trials are needed to determine their efficacy.
40
Additionally Non-Pharmaceutical agents such as fish oil have been proven to impact on
the metabolic syndrome.
THE IMPACT OF FISH OIL ON THE METABOLIC SYNDROME
CHARACTERISTIC
EFFECT OF FISH OIL
INSULIN RESISTANCE
IMPROVED
HIGH TRIGLYCERIDES
LOWERS 30%
HIGH BLOOD PRESSURE
MILD LOWERING
LOW HDL AND HIGH LDL
INCR HDL AND INCR BUOYANT LDL
EXCESS BLOOD CLOTTING
IMPROVES BLOOD FLOW AND
TISSUE PERFUSION WITHOUT INCREASING
BLEEDABILITY
WAIST CIRCUMFERENCE
PROMOTES EFFECTIVE FAT
>40 IN MEN
METABOLISM
>35 IN WOMEN
Likewise fish oil has a potential effect at the genetic level by toggling DNA switches.
The Impact of Fish Oil at the Genetic Level
LIPOXYGENASES
CYCLOOXIGENASE
CELL MEMBRANE
DIET
41
Is There Really Any Difference Between Re-esterified Triglyceride versus Ethyl
Ester Fish Oil?
A Scientific and Economic Assessment.
Larry J Alexander OD FAAO
Introduction
Fish oil has become a very popular supplement in our society because of multiple
reports of the benefits to health. These benefits are associated with the long-chain
omega 3 fatty acids in the form of eicosapentaenoic acid (EPA) and docosahexaenoic
acid (DHA), which are known to modulate the inflammatory system. It is estimated that
the combined intake of EPA and DHA in the United States is 100 to 200 mg/day with the
majority coming from alpha linolenic acid (ALA). These omega 3 fatty acids must be
consumed as humans cannot synthesize them. 1,2 Additionally, the pro-inflammatory
omega 6s dominate in the diet creating imbalance in the system and precipitating the
development of chronic disease. The only available recommendations for consumption
of essential fatty acids are shown in Table 1. 3
TABLE 1. ADEQUATE INTAKE (AI) FOR ESSENTIAL FATTY ACIDS
Essential Fatty Acid
Men
Women
ALA (> 50 years)
1.6 g/day
1.1 g/day
LA (> 50 years)
14 g/day
11 g/day
Abbreviations: ALA=α-linolenic acid; LA=linoleic acid; g=grams
Unfortunately the conversion of ALA (e.f. flaxseed oil) to the essential EPA and DHA is
very inefficient and LA may actually work to inhibit that conversion. 4 The most efficient
method of getting EPA and DHA into the system is by way of fish oil. In spite of
dramatic evidence regarding the health benefits of omega 3s from fish oil, the FDA has
not officially established guidelines regarding RDA.
A number of issues surround this supplement including the potential contamination of
the fish by pollutants in the environment. Bottom feeding coastal fish would naturally be
more susceptible to contamination by pollutants while top feeding middle-of-the-ocean
fish would be naturally less susceptible. Logic would also dictate that shorter lifespan
fish would also be less likely to be contaminated. The “ideal” fish is often characterized
as pelagic. The ideal way to get the fish oil into the system is to consume fresh pelagic
fish, or as a second choice, a can of sardines. As with most other nutrients the closer to
natural, the more effective the nutrient. But natural is not a realistic option for most
individuals because of recommended levels, lifestyle and the economics. Fish oil
supplements have become a reasonable alternative.
The American Heart Association (AHA) recognizes the benefits of Omega 3 fatty acids
and recommends: 5
1. That all adults eat fish (particularly fatty fish) at least two times a week.
Fish is a good source of protein and is low in saturated fat. Fish, especially oily species
like mackerel, lake trout, herring, sardines, albacore tuna, and salmon, provide
significant amounts of the two kinds of omega-3 fatty acids shown to be
42
cardioprotective, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The
AHA also recommends eating plant-derived omega-3 fatty acids. Tofu and other forms
of soybeans; walnuts and flaxseeds and their oils; and canola oil all contain ALA.
2. For patients with documented Coronary Heart Disease (CHD), the AHA
recommends 1 g of EPA and DHA (combined) per day. This may be obtained from
the consumption of oily fish or from omega-3 fatty acid capsules, although the decision
to use the latter should be made in consultation with a physician. The amount of EPA
and DHA in fish and fish oil is presented in the recent AHA Scientific Advisory on
omega-3 fatty acids and Cardiovascular Disease (CVD).
3. An EPA�DHA supplement may be useful in patients with hypertriglyceridemia.
Two to four grams of EPA�DHA per day can lower triglyceride 20% to 40%. Patients
taking more than three grams of these fatty acids from supplements should do so only
under a physician’s care.
Because of the potential of contamination, fish oil must be distilled, cleaned
(pasteurized) to minimize the risk. Thus the issue arises regarding the most effective
method to render fish oil safe, effective and efficient to the system. The basis of the
distillation process follows:
1. Crude fish oil (many different variations) is altered with ethanol
2. This mix is then heat distilled (molecular distillation) under a vacuum to remove
contaminants
3. The result is concentrated (50-70% 6 ) omega 3 molecules in an ethyl ester
package
4. This is then manipulated by different manufacturers to create variations on the
theme including addition of other factors or to reattach the molecules to a
glyceride backbone (re-esterified Triglyceride) in an attempt to closer simulate
the original long-chain omega 3s.
In the distillation process the raw fish oil is broken down, cleansed then reformulated
into two basic products, ethyl ester and triglyceride backbone. The body recognizes
both forms and uses appropriate enzymes to create a usable form of the omega 3. The
essence of the entire process is to get a supplement with the following characteristics:
 Safety and Tolerability
 Delivery of High Concentrations of EPA with Minimal Side Effects
 Delivery of High Concentrations of DHA with Minimal Side Effects
 Maximum bioavailability
 Stability
 Economical Considerations
The Basics
Triglycerides
Triacylglycerols, or more commonly referred to triglycerides (TG), are the molecular
form of dietary fats found in most foods. Triglycerides are the storage form of fatty
acids. The omega-3 fats present in all fish species are exclusively present as TGs. 7
43
Triglycerides are fats that are comprised of three fatty acids (i.e., EPA and DHA) linked
to a molecule of glycerol. Fatty acids are rapidly oxidized or highly unstable, and
therefore, the glycerol backbone in its natural state helps to stabilize the fat molecules
and prevent breakdown and oxidation. 8
Ethyl Esters
Ethyl Esters (EE) are synthetically derived by reacting fatty acids with ethanol to create
an alternate form of fat. 9 These alternative fats are created during the processing of
some fish oils. In this processing mode natural fatty acids are cleaved from their
glycerol backbone then linked to molecule of ethanol. This process is called reesterification, resulting in a product referred to as fish oil ethyl esters. 10 An end
product of this process is the concentration of the omega 3s resulting in a higher than
natural concentration of both EPA and DHA. This semi-synthetic product is then sold as
omega 3 fish oil concentrate. 9
To achieve a TG backbone fish oil, the distilled ethyl ester form must be reconverted by
removing the ethanol backbone and re-esterifying, which requires an additional step in
the process adding to the cost of production.
Which Form Offers the Maximal Bioavailability?
Metabolism of the Fatty Acids
To answer this question one must assess the physiology of absorption and metabolism
of the two variants, TG and EE. Dietary fish oil is digested in the small intestine by the
emulsifying action of bile salts and the hydrolytic activity of pancreatic lipase. This then
leaves two fatty acids and a monoglyceride in the intestinal fluid, which are absorbed
when combined with bile acids. The fatty acids and monoglycerides form complexes
with bile salts called micelles. Absorbed within the enterocyte (intestinal cells) of the
small intestine, the micelles (fatty acids and monoglyceride) are reassembled (reesterified ) to triglyceride and packaged with cholesterol and lipoproteins into
chylomicrons. The chylomicrons then go to the lymph system, then to the bloodstream
and are also reported to the liver. From this point the chylomicrons are modified and
utilized by the body in many different forms. The liver is the primary site for FA
metabolism and packaging into very low-density lipoproteins (VLDL) for delivery to
tissues via the circulatory system and modification to low-density lipoproteins (LDL). 7,1112
The digestion of EE fish oils is slightly different due to the lack of a glycerol backbone. 7
In the small intestine, it is again the pancreatic lipase that hydrolyzes the fatty acids
from the ethanol backbone, however, the fatty acid-ethanol bond is up to 50 times more
resistant to pancreatic lipase as compared to hydrolysis of triglyceride backbone fatty
acids. As a result the process loses some efficiencies. 13
44
The EEs that get hydrolyzed produce free fatty acids plus ethanol. The fatty acids are
taken up by the intestinal cells (enterocytes) and must be reconverted to TGs to be
reported in the blood. This requires a monoglyceride substrate from another source
whereas the TG form contains its own substrate. Again, a mild alteration of efficiencies.
7 While both achieve the same end, one conversion is more efficient.
When ethyl esters are consumed they are processed in the liver where the ethanol is
removed leaving fatty acids that must be rebuilt into a triglyceride to be effectively
metabolized. The process likewise begs the question “what happens to the ethanol that
has been removed?”
Research on Bioavailability
With this understanding of the digestion of fatty acids one may now attack the issue of
bioavailability. Numerous studies have assessed the absorption and bioavailability of
ethyl ester (EE) fish oils. Most studies have measured the amount of EPA and DHA in
blood plasma after ingestion of fatty acids as either rTGs or EEs but often without
properly controlling issues such as the framework of the consumption. The studies are
controversial regarding the bioavailability of EE versus TG. Luley et al 1990 compared
absorption of EPA and DHA from natural fish oil TG and EE and found no differences in
absorption. 14 Norday et al 1991 found that there was similar absorption of EPA and
DHA between EE and TG in an experiment with 40g fat test meals woven with
supplements. 15 Krokan et al 1993 discovered that EPA and DHA from EE was
comparable to that from natural TG, with the caveat that the FA in the TG variants were
of lower concentration. Said another way, TG variants delivered more bioavailability
with a lower concentration of FAs. 16 Hansen et al 1993 supplemented with 3.6 gm per
day of TG and EE to assess effect. Of particular interest is the fact that total serum
cholesterol and triglyceride levels were unaffected by the supplements. They concluded
hat EPA and DHA were equally incorporated into plasma phospholipids from both
formulations but the incorporation of EPA into plasma cholesterylesters from EE was
significantly lower with EE. Likewise both formulas had equal inhibitory effects on
platelet aggregation and thromboxane B2 production. 17 Beckermann et al 1990
presented conflicting data in a randomized triple cross-over trial with EPA and DHA
administered in TG (1.68/0.72 g), free fatty acids (1.35/1.065 g) and EE (1.86/1.27 g)
form. The mean relative bioavailability of EPA/DHA compared to TG was 186%/136%
from free fatty acids and 40%/48% from EE. Maximal plasma levels were 50% higher
with free fatty acids and 50% lower with EE as compared to TG. This equates to a 2.0
times multiple advantage for the TG form over the EE form. Free fatty acid tolerability
(belching) was much worse than either TG or EE. 18 Visioli et al 2003 corroborates the
fact that n-3 fatty acids from fish (100 g/day of Salmon oil) are more effectively
incorporated into plasma lipids than when administered as EE capsules and that
increments in plasma concentrations of EPA and DHA given as capsules are linearly
correlated with their intakes. This implies a “natural” advantage. 19 Additionally, it
should be noted that in contrast to rapidly absorbed triacylglycerols from fish, ethyl
esters are taken up more slowly within a 24 hour time frame and this must be factored
into the interpretation of studies. 20 El Boustani et al 1987 found that natural TG fish oil
45
results in 50% more plasma EPA and DHA after absorption in comparison to EE oils
and TG forms of EPA and DHA were shown to be 48% and 36% better absorbed than
EE forms. Likewise it was found that EPA incorporation into plasma lipids was found to
be considerably less and took longer when administered as an EE versus TG. 21
Lawson et al 1988 found the time course for the appearance and increase in
concentration of EPA in plasma TG relative to the maximal rise in alpha-linolenic acid
finding nearly 100% absorption of EPA and DHA as FFA whereas only 68% and 20% of
EPA as natural TG or EE were absorbed. 22
In an animal study in the rat, DHA in a TG variety supplement led to higher plasma and
erythrocyte DHA content than did DHA in an EE variety supplement, 23 and a higher
lymphatic recovery of EPA and DHA. 24
In a major human double-blinded, randomized, placebo controlled study, entitled,
Bioavailability of n-3 Fatty Acid Formulations, Dyerberg 1995 assessed the
bioavailability of the 5 most common fish oil concentrates. Seventy-two healthy subjects
were allocated to be given either re-esterified TG, EE, free fatty acid,
fish body oil, cod liver oil, or corn oil (control) preparations for two weeks. The dose of
EPA/DHA was an average of 3.34 g/day of EPA/DHA. Each group was given the
appropriate number of capsules twice daily with meals for 2 weeks. Table 2 lists the
dosages and composition of each of the supplements provided to the participants with
relative and absolute amounts of EPA and DHA.
TABLE 2. THE DOSAGE AND COMPOSITION OF THE CAPSULES WITH RELATIVE
AND ABSOLUTE AMOUNTS OF EPA AND DHA
Re-Ester
Free FA
Ethyl
Fish
Cod Liver Corn Oil
TG
Esters
Body Oil
Oil
Weight of 650
650
650
1000
500
650
Caps
Caps/day 5 + 5
5+5
5+5
6+7
17 + 17
5+5
EPA %
28.5
33.5
28.8
15.7
8.1
0
DHA %
19.8
21.5
21.4
11.4
11.0
0
n-6 FA % 4.0
2.2
3.9
2.5
2.2
56.7
Mono
13.3
12.1
15.7
25.9
51.8
29.0
unsat FA
%
* Sat fat
1.0
2.8
6.0
27.5
16.0
13.4
FA %
Tocoph
3.7
3.5
3.9
1.1
1.0
2.8
mg/day
EPA
1.85
2.18
1.87
2.04
1.38
0
g/day
DHA
1.29
1.40
1.39
1.48
1.87
0
g/day
EPA +
3.1
3.6
3.3
3.5
3.2
0
DHA
g/day
* Note the levels of Saturated Fats for Each Supplement
46
Examination of the patients occurred in the morning after an overnight fast both at
baseline and after two weeks. A summary of the results are presented in the following
figures and tables. Figures 1-3 demonstrate the differences between baseline values
and end of study values for EPA, DHA and EPA + DHA.
FIGURE 1. THE DIFFERENCE BETWEEN END OF STUDY AND BASELINE VALUES
OF EPA IN THE SUM OF SERUM LIPID FRACTIONS.
EPA mg/l
160
140
120
100
80
60
40
20
0
TG
FO CLO FFA EE CO
Supplement
Legend for Figures 1-3
TG = Triglyceride re-esterified , FO = Fish body oil, CLO = Cod Liver Oil,
FFA = Free fatty acids, EE = Ethyl Esters, and CO = Corn oil
FIGURE 2. THE DIFFERENCE BETWEEN END OF STUDY AND BASELINE VALUES
OF DHA IN THE SUM OF SERUM LIPID FRACTIONS.
50
40
30
DHA m g/l
20
10
0
TG FO CLO FFA EE CO
Supplement
47
FIGURE 3. THE DIFFERENCE BETWEEN END OF STUDY AND BASELINE VALUES
OF EPA + DHA IN THE SUM OF SERUM LIPID FRACTIONS.
200
150
EPA + DHA
mg/l
100
50
0
TG
FO CLO FFA
EE
CO
Supplem ent
A further fractionation into cholesterol esters (CE) phospholipids (PL) and triglycerides
(TG) is presented in Table 3.
TABLE 3. MEAN DIFFERENCE BETWEEN BASELINE AND END OF STUDY
REGARDING THE AMOUNT OF EPA AND DHA IN SERUM LIPIDS IN MG/L.
TG
FFA
EE
FO
CLO
CO
EPA
CE
DHA
71.0
53.1
46.3
55.0
48.4
2.7
4.8
3.5
3.2
4.2
5.6
1.5
EPA
+
DHA
75.8
56.6
49.5
59.2
54.0
4.2
EPA
PL
DHA
60.5
52.8
37.3
53.7
38.8
0.4
27.1
5.6
6.9
25.9
21.2
0.3
EPA
+
DHA
87.6
58.4
44.2
79.6
60.0
0.7
EPA
TG
DHA
15.9
15.4
10.4
11.7
11.8
-1.2
12.8
11.0
8.4
12.0
20.1
-0.9
EPA
+
DHA
28.7
26.4
18.8
23.7
31.9
-2.1
Under these testing conditions in a fasting state, the concentration of EPA + DHA was
highest in the re-esterified TG group and lowest in the corn oil (control) group. The
results showed that taking the mean increase in EPA plus DHA in all three plasma lipid
groups for the two natural fish oils (fish body oil and Cod liver oil) as unity or 100%, that
the mean relative bioavailability, unadjusted for dosage of EPA plus DHA from EE was
73%, from FFA 91% and from TG 124%. After adjustment for dosage factors, the
results were 76% from EE, 86% from FFA and 134% from TG. The study showed, the
bioavailability of EPA+DHA from the rTG was far superior (134%) compared to the
synthetic Ethyl Ester Form (76%) by a factor of 1.763. Interestingly enough the reesterified TG performed even better than the naturally occurring TG in the form of fish
body oil and cod liver oil. 25
48
Relationship to Diet
Another bioavailability issue revolves around when and how the fish oil is consumed.
One study demonstrated that only 20% of omega 3s in the ethyl ester form were
absorbed unless taken with a high fat meal. The high fat meal raised absorption to
60%. 19 The triglyceride backbone fish oil variants likewise demonstrate a difference
when consumed with a high fat meal (44 g of fat versus 8 g of fat). In one study it was
reported that absorption of EPA increased from a base level of 69% to 90% when the
fish oil was consumed with a high fat meal while DHA was seemingly unaffected. 26
While this is compelling research, clearly it is ill-advised to consume a 44 g fat meal to
achieve better absorption. The pearl from this research is that omega 3 supplements
should be taken with a meal, preferably one with an nutritionally acceptable amount of
fat.
The Economics
Arguments are offered regarding the excessive costs of TG backbone versus ethyl ester
omega 3 fatty acids. These arguments are usually attributable to the “extra costs”
involved in the manufacturing of these products. Assume that 1000 mg of EPA into the
system is the goal and estimated absorption rates from the Dyerberg study 25 are
employed. Also assume that this is to be accomplished with a relatively low fat meal to
avoid potential complications systemic complications. If human referenced percentages
were used, it could be assumed that 134% bioavailability would occur with TG
backbone and 76% bioavailability would occur with ethyl ester. It could then be
concluded that TG backbone is approximately 1.7 X (Bioavailability Factor) more
absorbable. To get the equivalent of 1000 mg of EPA with ethyl ester, the patient would
have to consume 1700 mg. From an economics standpoint one can compare a couple
of commercially available products and extract the cost per mg. These prices were
obtained online January 1, 2010 and are retail estimates. The results are shown in
Table 5.
TABLE 5. COSTS OF OBTAINING 1000 MG OF EPA UTILIZING THE
BIOAVAILABILITY FACTOR
Ethyl Ester Product
TG Backbone Product
Products 1 and 2
$1.67/day to achieve
$0.96/day to achieve
1700 mg
1000 mg
Products 3 and 4
$1.89/day to achieve
$1.69/day to achieve
1700 mg
1000 mg
Even if one argued no difference in the bioavailability factor of TG versus EE the
comparison would be as shown in Table 6.
49
TABLE 6. COSTS OF OBTAINING 1000 MG OF EPA WITHOUT USING THE
BIOAVAILABILITY FACTOR
Ethyl Ester Product
TG Backbone Product
Products 1 and 2
$0.98/day to achieve
$0.96/day to achieve
1000 mg
1000 mg
Products 3 and 4
$1.10/day to achieve
$1.69/day to achieve
1000 mg
1000 mg
As one can readily see that there is no great difference in costs between products 1, 2
or 3 even if one assumes equal bioavailability. The most economical product in both
assessments is Product 2. The proper way to assess the economics is to calculate
costs for all products is shown in Figure 4.
FIGURE 4. FORMULA FOR CALCULATING COST PER DAY FOR SUPPLEMENT
REQUIREMENTS
$ per bottle
Capsules / bottle
=
COST $ /capsule
Desired Dosage
Mg EPA /capsule
COST $ /day
=
=
Number of capsules needed/ day
$ / capsule X Number of capsules needed / day
With or without the bioavailability factor, the doctor should assume some role in
obtaining the “most effect for the money spent” for their patients.
Which Form of Supplement Offers More Stability?
Live fish or fresh fish are probably going to offer the maximum stability for provision of
Omega 3s. All fish oils are particularly susceptible to oxidation. Vitamin E is often
added as a natural anti-oxidant to help delay this oxidation. 27 Fish oil has an inherent
expiration date with 6 months shelf life often anecdotally cited. The fishy taste is one of
the indications of oxidation. This fishy taste, or eructation (burp-back), may be masked
by providing an enteric coating for inferior fish oil. The most common side effect of the
consumption of fish oil is gastrointestinal disturbance that increases with higher levels of
supplementation.28 A reasonable method of assessing the freshness or levels of
oxidation is to actually bite one of the capsules to experience the fishy flavor. Oxidized
fish oil is not pleasant to the taste.
According to one report DHA in fish oils in the form of ethyl esters are much less stable
than those in the natural triglyceride form. In the study the EE form of DHA was more
reactive, and quickly oxidized, demonstrating that EE fish oils are far less stable and
more readily produce harmful oxidation products. 29 Another study analyzed the
stability of DHA in phospholipid, triacylglycerol, and EE form. Looking at a 10-week
oxidation period, the EE DHA oil decayed 33% more rapidly. 30
50
Summary
Essential fatty acids are critical to the maintenance of health. They must be consumed
to create EPA and DHA, which are employed in the balance of the immune system as it
relates to inflammation. Most diets are woefully low in the long-chain omega 3 fatty
acids that are most efficient in the provision of EPA and DHA. A number of issues have
been addressed regarding the differences between fish oil supplements. There is little
argument that eating foods rich in omega 3s or supplementing with omega 3s is
beneficial to health. The American Heart Association among other groups readily attest
to that fact.
As a practitioner or consumer, the question is which of the supplements appear to be
most beneficial regarding:
 Safety and Tolerability?
 Delivery of High Concentrations of EPA with Minimal Side Effects?
 Delivery of High Concentrations of DHA with Minimal Side Effects?
 Maximum bioavailability?
 Stability?
 Economics Considering Bioavailability?
Safety and tolerability are a minor issue. There were reports of increased bleed-ability
associated with omega 3 consumption, but those issues have been resolved with the
assessment by Harris stating that the benefits of triglyceride lowering with omega-3 fatty
acids more than outweigh any theoretical risks for increased bleeding. 31 The primary
tolerability issues surround the belching and gastrointestinal problems. This problem
seems to occur more frequently with the FFA products and with increased dosing of any
of the fish oils. Gastrointestinal issues are also exacerbated by using expired products.
Delivery of high concentrations of both EPA and DHA appear to occur more efficiently
with the triglyceride variations and even better with re-esterified TG. Apparently the
bioavailability between EE and TG variations is somewhat related to absorption time
differences. Also it appears that consumption of high fat meals improves the
bioavailability of all variants but of course that creates other issues of risk.
Stability is an issue for all supplements, but the data seems to indicate that EE
variations are more easily oxidizable than the rTG variants. Care must be exercised in
looking at the expiration dates to assure maximum bioavailability without the
complications of putting more oxidants in the system.
All arguments aside, the most critical aspect of healthcare is patient compliance. The
best drug, the best surgery, the best advice, or the best supplement has little meaning
without patient buy-in and patient compliance. The research is overwhelming regarding
the benefits of maintaining the proper balance of Omega 3s with Omega 6s. The
balance has to be there to limit chronic inflammation and the consequences thereof.
Those consequences are related to morbidity and mortality, eye health and ocular
comfort. To achieve that end patient education is paramount. Additionally the provision
51
of the most efficient and effective agent is critical, as well as getting the most efficacy for
money spent.
References:
1. Ervin RWJ, WangC, Kennedy-StephensonJ. Dietary intake of fatsand fatty acids for the United States
population: 1999–2000. Adv Data Vital Health Stat 2004;348. [DHHS publication no. (PHS) 2005–1250
04 – 0565.]
2. Wang CM, Lichtenstein A, Balk E, et al. Evidence report/technology assessment no. 94 (Prepared by
Tufts-New England Medical Center Evidence-based Practice Center, under contract no. 290-02-0022).
Effects of omega-3 fatty acids on cardiovascular disease. Rockville, MD: Agency for Healthcare Research
and Quality, 2004. (AHRQ publication no. 04-E009-2.
3. Food and Nutrition Board, Institute of Medicine. Dietary Fats: Total Fat and Fatty Acids. Dietary
Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino
Acids. Washington, D.C.: National Academies Press; 2002:422-541.
4. Ackman RG. The absorption of fish oils and concentrates. Lipids 1992;27:858-862.
5. Kris-Etherton PM, Harris WS, Appel LJ and for the AHA Nutrition Committee. Omega-3 Fatty Acids and
Cardiovascular Disease: New Recommendations From the American Heart Association. Arterioscler
Thromb Vasc Biol 2003;23;151-152.
6. Dyerberg J, Bang HO, Stoffersen E, et al. Eicosapentaenoic acid and prevention of thrombosis and
atherosclerosis. Lancet 1978;ii:117-119.
7. Carlier H., Bernard A, Caseli A. Digestion and absorption of polyunsaturated fatty acids. Reprod Nutr
Dev 1991; 31: 475-500.
8. Segura R. Preparation of fatty acid methyl esters by direct reesterification of lipids with aluminum
chloride methanol. J Chromatogr 1988;441:99-113.
9. Saghir M, Werner J, Laposata M. Rapid in vivo hydrolysis of fatty acid ethyl esters, toxic nonoxidative
ethanol metabolites. Am J Physiol 1977;273:G184-190.
10. Mogelson S, Pieper SJ, Lange LG. Thermodynamic bases for fatty acid ethyl ester synthase
catalyzed esterification of free fatty acid with ethanol and accumulation of fatty acid ethyl esters.
Biochemistry. 1984 Aug 28;23(18):4082-4087.
11. Fave G, Coste TC and Armand M. Physicochemical properties of lipids: New strategies to manage
fatty acid bioavailability. Cellular and Molecular Biology 2004;50:815-831
12. Lambert MS, Botham KM, Mayes PA. Modification of the fatty acid composition of dietary oils and fats
on incorporation into chylomicrons and chylomicron remnants. Br J Nutr 1997;76:435-445.
13. Yang LY, Kuksis A, Myher JJ. Lipolysis of menhaden oil triacylglycerols and the corresponding fatty
acid alkyl esters by pancreatic lipase in vitro: a reexamination. J Lipid Res. 1990; 31(1):137-147.
14. Luley C, Wieland H, Gruwald J. Bioavailability of omega-3 fatty acids: ethylester preparations are as
suitable as triglyceride preparations. Akt Ernaehr-Med 1990;15:122-125.
15. Norday A, Barstad L, Connor WE, hatcher L. Absorption of the n-3 eicosapentaenoic and
docosahexaenoic acids as ethyl esters and triglycerides by humans. Am J Clin Nutr 1991;53:1185-1190.
52
16.Krokan HE, Bjerve KS, Moerk E. The enteral bioavailability of eicosapentaenoic acid and
docosahexaenoic acid is as good from ethyl esters as from glycerol esters in spite of lowere hydrolytic
rates by pancreatic lipase in vitro. Biochim Biophys Acta 1993;1168:59-67.
17. Hansen JB, Olsen JO, Wilsgard L, et al. Comparative effects of prolonged intake of highly purified
fish oils as ethyl ester or triglyceride on lipids, haemostasis and platelet function in normolipaemic men.
Eur J Clin Nutr 1993;47:497-507.
18. Beckermann B, Beneke M, Seitz I. Comparative bioavailability of eicosapentaenoic acid and
docosahexaenoic acid from triglycerides, free fatty acids and ethyl esters in volunteers.
Arzneimittelforschung 1990;40(6):700-704.
19. Visioli F, Rise P, Barassi MC, et al, Dietary intake of fish vs. formulations leads to higher plasma
concentrations of n-3 fatty acids. Lipids 2003;38:415-418.
20. Rupp H, Wagner D, Rupp T, et al. Risk stratification by the "EPA+DHA level" and the "EPA/AA ratio"
focus on anti-inflammatory and antiarrhythmogenic effects of long-chain omega-3 fatty acids. Herz
2004;29:673-685.
21. Boustani SE, Colette C, Nonnier L, et al. Enteral absorption in man of eicosapentaenoic acid in
different chemical forms. Lipids 1987;22:711-714.
22. Lawson LD, Hughes BG. Human absorption of fish oil fatty acids as triacylglycerols, free acids, or
ethyl esters. Biochem Biophys Res Commun, 1988;52:328-335.
23. Valenzuela A, Valenzuela V, Sanhueza J, Nieto S. Effect of supplementation with docosahexaenoic
acid ethyl ester and sn-2 docosahexaenyl monoacylglyceride on plasma and erythrocyte fatty acids in
rats. Ann Nutr Metab 2005; 49:49-53.
24. Ikeda I, Sasaki E, Yasunami H, et al. Digestion and lymphatic report of eicosapentaenoic and
docosahexaenoic acids given in the form of triacylglycerol, free acid and ethyl ester in rats. Biochim
Biophys Acta 1995; 1259: 297-304.
25. Dyerberg, J., Madsen, P., Moller, J. et al . Bioavailability of n-3 Fatty Acid Formulations. Pp 217-226
In n-3 Fatty Acids: Prevention and Treatment in Vascular Disease. Bi & Gi Publishers, Verona-Springer
Verlag, London 1995.
26. Lawson LD, Hughes BG. Absorption of eicosapentaenoic acid and docosahexaenoic acid from fish oil
triacylglycerols or fish oil ethyl esters co-ingested with a high-fat meal. Biochem Biophys Res Commun.
1988;156(2):960-963.
27. Valk EE, Hornstra G. Relationship between vitamin E requirement and polyunsaturated fatty acid
intake in man: a review. Int J Vitam Nutr Res. 2000;70(2):31-42.
28. Gissi-HF Investigators, Tavazzi L, Maggioni AP, et al. Effect of n-3 polyunsaturated fatty acids in
patients with chronic heart failure (the GISSI-HF trial): a randomised, double-blind, placebo-controlled
trial. Lancet. 2008 Oct 4;372(9645):1223-30.
29. Yoshii H, Furuta T, Siga H, Moriyama S, et al. Autoxidation kinetic analysis of docosahexaenoic acid
ethyl ester and docosahexaenoic triglyceride with oxygen sensor. Biosci Biotechnol Biochem
2002;66:749-753.
30. Song JH, Inoue Y, Miyazawa T. Oxidative stability of docosahexaenoic acid-containing oils in the form
of phospholipids, triacylglycerols, and ethyl esters. Biosci Biotechnol Biochem. 1997;61:2085-2088.
53
31. Harris WS. Expert Opinion: Omega-3 fatty acids and bleeding-cause for concern? Am J Cardiol
2007;99[suppl]:44C–46C.
The Impact of Vitamin D3 on the Immune (Inflammatory) System
Vitamin D is a fat-soluble vitamin (in actual fact a steroid hormone) essential for
promoting calcium absorption in the gut and maintaining adequate serum calcium and
phosphate concentrations to enable normal mineralization of bone and to prevent
hypocalcemic tetany. It is also needed for bone growth and bone remodeling. Severe
Vitamin D deficiency in infants and children results in rickets with growth plate enlarging
without the support of mineralization of the long bones. Vitamin D3 (cholecalciferol) can
be synthesized by humans in the skin upon exposure to ultraviolet-B (UVB) radiation. It
can also be obtained from the diet, but is fat-soluble. Sufficient vitamin D prevents
rickets in children and osteomalacia in adults and, together with calcium, vitamin D
helps protect older adults from osteoporosis. A quantitative meta-analysis recently
concluded that at a mean daily dose of vitamin D of 528 IU there was a significant
decrease in death (7% to 8%) for those using vitamin D supplement.
It has been estimated that 50% to 60% of people do not have satisfactory vitamin-D
status, likely related to urbanization, demographic shifts, decreased outdoor activity, air
pollution and global dimming, as well as decreases in the cutaneous production of
vitamin D with age. One prospective cohort study demonstrates for the first time that low
25-hydroxyvitamin-D and 1,25-dihydroxyvitamin-D levels are associated with increased
risk in all-cause and cardiovascular mortality compared with patients with higher serum
vitamin-D levels. Another recent study found that 40.7% of patients with chronic
migraine were deficient in 25-hydroxyvitamin D. The study also showed that the longer
individuals had chronic migraine, the more likely they were to be vitamin D deficient.
Vitamin D deficiency is widespread among patients being treated for osteoporosis, and
such deficiency should be treated aggressively. Recent reports have increased the
awareness of a much broader role for vitamin D. Vitamin D is involved in differentiation
of tissues during development and in proper functioning of the immune system. Over
900 different genes are now known to be able to bind the vitamin D receptor, through
which vitamin D mediates its effects. The majority of effects of vitamin D in the body are
related to the activity of 1,25(OH)2D including 50 specific genes. 1,25(OH)2D also
inhibits proliferation and stimulates differentiation of cells as well as having activity as an
immune system modulator. It is even suggested that 1,25(OH)2D may enhance
innate immunity and protect against many autoimmune disorders. Evidence also
continues to accumulate suggesting a beneficial role for vitamin D in protecting against
autoimmune diseases, including multiple sclerosis and type I diabetes, as well as some
forms of cancer, particularly colorectal and breast. A recent article concludes that there
is ample biological evidence to suggest an important role for vitamin D in brain
development and function, and that supplementation for groups chronically low in
vitamin D is warranted. Since Calcium is so linked to neurodegeneration, one may
hypothesize a link between Vitamin D, the immune system and the negative actions of
the calcium ion.
54
Hypovitaminosis D, especially at levels less than 30 ng/mL, is associated with an
increased risk for Myocardial Infarct in men. Vitamin D is likely to exert its effect on the
risk for cardiovascular disease via vascular smooth muscle cell proliferation,
inflammation, vascular calcification, the renin-angiotensin system, and blood pressure.
The rate of cardiovascular disease–related deaths is greater at higher latitudes, lower at
higher altitudes, and higher in the winter months — all associations related to vitamin D
deficiency. The vitamin D axis affects vascular smooth muscle cell proliferation,
inflammation, vascular calcification, the renin-angiotensin system, and blood pressure,
all of which affect cardiovascular disease and MI risk, but evidence linking
hypovitaminosis D and MI is sparse. Current recommendations for vitamin D are 200 to
600 IU per day, which may be inadequate to prevent cardiovascular disease. Another
recent study demonstrated that use of calcitriol in patients with stage III or IV Chronic
Kidney Disease (CKD) with hyperparathyroidism is associated with reduced risk for
mortality and long-term dialysis and that the use of calcitriol in patients with stage III or
IV CKD with hyperparathyroidism is associated with increased risk for hypercalcemia.
CKD affects more than 10% of the US population with disturbances in vitamin D and
mineral metabolism.
For the first time Vitamin D deficiency has been linked to a poorer outcome in breast
cancer. Risk factors for Vitamin D deficiency include: dark skin, sunscreens, clothing
covering the majority of the skin, increasing age, gastrointestinal disorders associated
with fat malabsorption, obesity, bariatric surgery, ill-advised dieting, and a poor diet.
The results of most clinical trials suggest that vitamin D supplementation can slow bone
density losses or decrease the risk of osteoporotic fracture in men and women. Vitamin
D3 (cholecalciferol) is now known to be greater than three times more potent than
vitamin D2. In order for vitamin D supplementation to be effective in preserving bone
health, adequate dietary calcium (1,000 to 1,200 mg/day) should also be consumed. In
general adults should take a supplement that supplies 400IU of vitamin D3 daily and
should have 10-15 minutes of sun exposure at least three times a week as close to
noon as possible. Should sunlight exposure be unattainable, 800IU of D3 is advised. In
reality it is best to aim for seurm levels of 80 nmol/L to minimize risk of disease.
Toxicity-hypercalcemia-can lead to bone loss, kidney stones, and calcification of the
heart and kidneys. Because the consequences of hypervitaminosis D and ensuing
hypercalcemia are severe, the Food and Nutrition Board established a very
conservative upper limit of 2,000 IU/day (50 mcg/day) for children and adults while other
reports suggest 10,000IU is tolerated.
A recent study, while equating low vitamin D levels to an increased risk of mortality,
concludes that they would not advise people to take supplements without knowing their
vitamin-D levels and that the most sensible advice for those wanting to ensure their
levels remain optimal is to spend 10 to 15 minutes per day in the sun and to eat vitaminD-fortified foods, such as milk and oily fish.
More recent studies relate the importance of Vitamin D3 to the eyes. Based on
encouraging preliminary findings, more study is recommended on the benefit of
55
antioxidant supplements for age-related macular degeneration and of selenium for
cancer prevention. In contrast to the state of the art for antioxidant supplements, there is
strong and compelling support for the health benefits of supplements of Vitamin D and
calcium when intake/status of these nutrients is not optimal. Thus, specific
recommendations for these supplements in older adults are warranted. It has been
shown that Levels of serum vitamin D were inversely associated with early AMD but not
advanced AMD and that milk intake was inversely associated with early AMD.
Coincidently fish intake was inversely associated with advanced AMD in this report. It
was reported that consistent use vs nonuse of vitamin D from supplements was
inversely associated with early AMD only in individuals who did not consume milk daily.
Carrying this one step further, it was found that Higher levels of Bone Mineral Density
(BMD) may be associated with lower risk for ARM. The underlying mechanism is
unknown, although BMD may be a marker for lifetime endogenous estrogen exposure.
Vitamin D is present in only a few foods (e.g. fatty fish), and is also added to fortified
milk, but our supply typically comes mostly from exposure to ultraviolet rays (UV) in
sunlight. UV from the sun converts a biochemical in the skin to vitamin D, which is then
metabolized to calcitriol, its active form and an important hormone. Formation of vitamin
D by UV can be 6 times more efficient in light skin than dark skin, which is an important
cause of the known widespread vitamin D deficiency among African Americans living in
northern latitudes. The issue of how Vitamin D relates to the general and ocular health
of individuals is evolving with research outstripping one’s ability to “keep up.” A recent
AARP magazine presented the following as cited by Michael F. Holick PhD, MD of the
VitaminD, Skin and Bone Research Laboratory of Boston University Medical Center.
“To get the vitamin D value of ten minutes’ exposure to sunlight, you’d have to
eat… 6 ½ pounds of shitake mushrooms or 150 egg yolks or 3 ¾ pounds of fresh
farmed salmon or 30 servings of fortified cereal or 2 1/6 pounds of sardines or 30
cups of fortified orange juice.” Do the calorie count on that exercise and realize
that food sources of vitamin D actually complicate the issue.
Additional Potential Anti-Inflammatory Agents
Turmeric (Curcumin)
Curcumin is a component of turmeric, the yellow spice in curry. It has been shown to be
a potent immunomodulatory agent that modulates activation of T cells, B cells,
macrophages, neutrophils, natural killer cells, and dendritic cells. It also down-regulates
various proinflammatory cytokines including TNF, IL-1, IL-2, IL-6, IL-8, IL-12 and
chemokines while concurrently enhancing the antibody responses. It is a phytophenolic
compound with proven antioxidant, anti-inflammatory, anti-infectious and anticancer
activitiy and is potentially applicable to the treatment of malignancies, diabetes,
allergies, arthritis, Alzheimer’s, Crohn’s disease, inflammatory bowel disease, psoriasis,
idiopathic inflammatory orbital pseudotumors, chronic anterior uveitis, pterygia, COPD,
experimental abdominal aortic aneurysms and other chronic diseases. There is even
one report suggesting that Curcumin may be beneficial in the prevention of posterior
capsular opacification. One of the more obvious applications is to the management of
56
dysfunctional tear syndrome which is known to have immune-related inflammatory
response. In this application, the effect is to mediate the transcription factor NF-k B
which has the ability to block the inflammatory and apoptotic effect of TNF-alpha. Its
activity is thought to occur by inhibition of prostaglandin E (2). The effects of Curcumin
are mediated through the regulation of various transcription factors, growth factors,
inflammatory cytokines, protein kinases, and other enzymes. Curcumin Inihibits such
mediators of inflammation as NFkB, cyclo-oxygenase-2 COX 2, lipooxygenase-OOX,
and inducible nitric oxide synthase. Curcumin has at least ten known neuroprotective
actions and targets multiple Alzheimer Disease (AD) pathogenic cascades, making it a
strong candidate for use in the prevention or treatment of major disabling age-related
neurodegenerative diseases like AD, Parkinson’s and stroke. Curcumin affects many
aspects of angiogenesis, downregulating such proantiogenic proteins as VEGF and
BFGF and inhibiting signal transduction pathways. The anti-inflammatory and antiVEGF capabilities make Curcumin a possible choice for intervention in ARMD.
The suggested daily dosage is 500 to 1000 mg. Toxicities were not experienced at
levels of 3600 to 8000 mg/day for four months with the exception of nausea and
diarrhea. There are, however, issues with bioavailability and methods to enhance this
are under investigation.
Quercetin
Quercitin is an antioxidant flavonoid that prevents the oxidation of LDL. Oxidized LDL
plays a key role in vascular damage. Quercitin is also well recognized as the antiallergy supplement. Quercitin works synergistically with vitamin E to protect the purified
rod outer segments (ROS) and retinal pigment epithelium (RPE) in the eye from freeradical-induced membrane lipoperoxidation and damage. Quercitin can modulate
endothelial properties including nitric oxide production and expression of adhesion
molecules. Quercitin inhibits the enzyme hyaluronidase from causing a breakdown of
the collagen matrix of connective tissue and ground substance. Quercitin suppresses
the generation of superoxide, hydroxyl and lipid peroxy radicals.
Quercitin combined with stinging nettle and bromelain is a well-known supplement that
can positively effect allergies and as such impacts on the inflammatory cascade
associated with the immune system.
Vitamin C
Vitamin C (Ascorbic Acid) is required for collagen synthesis, the synthesis of
norepinephrine, carnitine and the conversion of cholesterol to bile acids. The
overwhelming fame of Vitamin C is associated with its role as an antioxidant for the
protection of molecules from damage by free radicals and reactive oxygen species
(ROS) created during metabolism and toxin exposure such as smoking creating
oxidative stress.
There is the suggestion that vitamin supplementation suppresses leukocyte adhesion
57
and thus endothelial dysfunction, associated with increase in iris blood flow perfusion in
diabetes. Regarding Vitamin C as a part of an anti-ARM formula, it has been shown that
blue light could induce DNA damage to RPE cells but vitamin C could protect the RPE
cells from the blue light-induced DNA damage. Vitamin C enhances PGE1 and thus
assists in the regulation of T cell function. Vitamin C increases killer T cell
activity and B cell function. It also increases glutathione levels. It is known to
protect against viruses by strengthening connective tissue and neutralizing
toxins released by phagocytes.
Vitamin E
Alpha-tocopherol is the only form of Vitamin E in the human body and is the form
recommended for supplementation. Vitamin E is the body’s primary fat-soluble
antioxidant and it must be obtained from food or supplements. As an antioxidant Alphatocopherol neutralizes free radicals then must be transformed back to Alpha-tocopherol
with the assistance of other antioxidants such as Vitamin C. Vitamin E travels through
the body in low-density liporoteins which protect them from from oxidation. Vitamin E
is known to affect the expression and activity of immune and inflammatory cells,
to enhance vasodilation and to inhibit the activity of the cell signaling molecule protein
kinase C (PKC).
Alpha-tocopherol at 400 to 800 IU per day is an effective antioxidant with fame in
reducing the oxidation of low-density lipoproteins to prevent formation of foam cells and
thus atherosclerotic plaques. Most interest in vitamin E surrounds the cardiovascular
issue. While the studies are variable most point to the fact that vitamin E consumption
is associated with some degree of risk reduction in cardiovascular disease. Results of
trials of intervention with vitamin E in vascular disease have been totally non-definitive.
In the framework of diabetes, the studies are likewise inconsistent and contradictory.
Data from the NHANES 1999-2000 indicate that mean dietary intake of alphatocopherol is 6.3 mg/day and 7.8 mg/day for women and men, respectively. These
intakes are well below the current intake recommendations of 15 mg/day. It is
estimated that more than 90% of Americans do not meet daily dietary recommendations
for vitamin E.
Alpha-tocopherol has been shown to enhance the immune system. Additionally, it
works synergistically with Omega 3 FFAs to protect cells from TNF-a induced apoptosis.
Supplementation with Vitamin E has also been shown to increase B cell activity in the
aging patient. Vitamin E also works synergistically with Vitamin C to reduce
inflammatory prostaglandins and increase T cells.
Upper levels for safety of consumption of vitamin E are established by the Food and
Nutrition Board of the Institute of Medicine to minimize hemorrhage for alpha-tocopherol
supplements are 1,000 mg/day of alpha-tocopherol in any form (equivalent to 1,500
IU/day of RRR-alpha-tocopherol or 1,100 IU/day of all-rac-alpha-tocopherol). Drug
interactions must be taken into account realizing that hemorrhage at excessive dosages
58
is a potential issue. Any pharmaceutical agents, foods or supplements such as gingko
biloba should raise the caution of interaction.
Vitamin A
Vitamin A is a generic term referring to related compounds. It is available in a
preformed variation called retinol found in many animal products. Preformed retinol can
be toxic at levels above 10,000 IU. The other form is natural beta carotene
(carotenoid), which is from fruits and vegetables and is used to form its own vitamin A.
Carotenoids comprise a class of natural fat-soluble pigments, which are found in
numerous fruits and vegetables and are attributed with the characteristic of minimizing
photo-oxidative damage to tissue. Retinol is an alcolol and retinal is an aldehyde, both
referred to as preformed vitamin A. Retinol, retinal, and retinoic acid are retinoids.
Beta-carotene and other carotenoids that can be converted by the body into retinol are
provitamin A variations. Not all carotenoids synthesized by plants are provitamin A
carotenoids.
Additionally vitamin A is responsible for the normal functioning of the immune
system especially in the skin and mucosal cells. The initial protective system from
infection in the body is the mucosal system. Likewise the differentiation of white blood
cells is dependant on vitamin A and retinoic acid. Absence of vitamin A from the diet
significantly impacts on tear quality and is responsible for the genesis of Bitot’s spots
associated with severe dry eye. Vitamin A deficiency among children continues to be a
leading cause of preventable blindness. Vitamin A deficiency is considered by some to
be a nutritionally acquired immunodeficiency disease
The results of the Beta-Carotene And Retinol Efficacy Trial (CARET) suggest that highdose supplementation of vitamin A and beta-carotene should be avoided in people at
high risk of lung cancer.
Uses of large dosages of Vitamin A are not without risk and should be approached
cautiously. Utilization in the management of retinitis pigmentosa showed that with
common forms of retinitis pigmentosa that supplementation with 4,500 mcg (15,000
IU)/day of preformed vitamin A (retinol) significantly slowed the loss of retinal function
over a period of 4-6 years. In contrast, supplementation with 400 IU/day of vitamin E
increased the loss of retinal function by a small but significant amount, suggesting that
patients with common forms of retinitis pigmentosa may benefit from long-term vitamin
A supplementation but should avoid vitamin E supplementation at levels higher than
those found in a typical multivitamin. Both vitamin A serum levels and a fasting lipid
profile should be obtained prior to initiation of therapy.
A safe recommendation would be that combined multivitamin supplements should
provide no more than 2,500 IU of vitamin A or 5,000 IU of vitamin A, of which at least
50% comes from beta-carotene.
59
Summary
Chronic inflammation is a significant problem in health care today and the fuel for the
fire of inflammation is diet, nutrition, and behavior. While prescriptive anti-inflammatory
agents continue to be necessary to manage chronic inflammation, the patient and
doctor can actively participate in the process by attempting to balance the system
through methods of immunomodulation. There are a number of methods that can
accomplish the balance  including diet, exercise, nutritional modification and
potentially supplementation within the framework of the diet.
Acute inflammation as directed by the immune system is critical to survival while chronic
inflammation is the harbinger of morbidity and mortality.