Download Experimental Studies of the Blood-Brain Barrier

Experimental
Studies
of the Blood-Brain
DAVID
Laboratory
of Chemical
Pharmacology,
National
P.
Cancer
Barrier
RALL
Institute,
National
In.stitutes
of Health
, Bethe8da
, Maryland
SUMMARY
The problems
agents
associated
in l)articular
into
with the entry
the
brain
and
of drugs in general
cerebrospinal
fluid
have
and anti-leukemic
been
considered.
Technics which might allow more drug to enter the central nervous system have been
discussed and their limitations noted.
A new method of ventriculolumbar
perfusion
has been
described
which
may offer increased
therapeutic
effectiveness.
The malignant cells of acute leukemia enjoy unusual
prerogatives in their battle against successful chemother
apy. Like guerrilla forces in jungle warfare, these cells
Thus the cells must be eradicated.
Although other possi
bilities might be considered, optimal chemotherapy
must
destroy all leukemic cells everywhere.
possess
hidden
sanctuaries
into
which
the
attackers
can
How may this be done? Dr. Thomas in the preceding
not penetrate.
And in these pharmacologic sanctuaries
article (22) has most beautifully demonstrated
1 pharma
they can, if not completely annihilated, regroup and mul
cologic sanctuary for leukemia cells, and has indicated the
tiply.
One such sanctuary,
as suggested
by the title of
difficulties inherent in conventional chemotherapy.
It is
this l)aper, lies within the central nervous system (CNS).
the purpose of this communication to consider the reasons
Before considering the problems of eradicating the leu
why conventional agents penetrate poorly into brain and
kemic cells ill these areas, it is pertinent
to consider
cerebrospinal fluid (CSF) and to suggest possible methods
whether this effort is necessary.
How much will be of attack upon these pharmacologically
sequestered cells.
gained if the effort is successful?
Leukemia may develop
Perhaps, with the advent of the nitrosoureas, this is less
from
a single,
essentially
nonrepetitive
event
; alterna
necessary.
These agents, small molecules, nonionized at
tively, it may develop repetitively
from a continuing
body pH, and highly lipoid-soluble, can cure murmne me
process, such as a persistent
viral infection.
In the first
ningeal leukemia (19). They can do this for two reasons.
instance
the relapse
that follows
clinical
remission
is clear
They are intrinsically potent anti-leukemic
agents, and
evidence that the chemotherapy
failed to eradicate all they P0S5C5Sthe physicochemical properties which permit
leukemic cells.
The duration
of remission may represent
free and rapid passage from blood stream into brain and
the period of time necessary for the redevelopment
of a CSF. Perhaps by the time this is published, a nitro
sufficient
leukemic
population
to cause
overt
disease
from
sourea will have been shown to cure meningeal leukemia
the few cells spared from the chemotherapy.
In the
in man. In any event, the story of the recent research
second instance the period of remission might be either
leading to a fairly complete understanding
of the blood
the time necessary for reinduction if all the leukemic cells brain and blood-CSF barrier is interesting
enough to
had been eradicated, or the time for redevelopment if leu
stand by itself, unbuttressed
by practical application.
kemic cells remained after chemotherapy.
Further, the problems raised by the passage of drugs
It is clear that in the first instance the @)harmacolOg1C through these barriers are in many ways common to drug
asylum offered in such areas as the CNS can be of critical
passage into many other tissues and into cells in general
importance.
In the extreme example, if only 1 cell
(9, 14, 20).
Although we have mentioned the blood-brain and blood
remains
in the
CNS
after
chemotherapy,
florid
systemic
CSF barriers, it should be clear that we are dealing with
leukemia will develop in time. In the 2nd instance, how
ever, is the pharmacologic
sanctuary of critical impor
a 3-component system (Chart 1), which includes the CSF
tance?
I think
it is.
If all the
systemic
cells
and
all the
brain barrier. The locus of the blood-brain barrier prob
ably is the tightly packed sheath of glial and neuronal
viruses are eradicated,
the disease will be cured.
But if
cells or virus remain within the CNS, or anywhere else, cells which completely surrounds the brain capillary.
The
they will multiply and repopulate the body and lead to blood-CSF barrier is predominantly
the choroid plexus, a
florid leukemia.
The 1st step to the cure of leukemia,
solid sheet of epithelial secretory cells between the rich
then, is the eradication of all leukemic cells. If this is not
choroidal blood supply and the cerebrospinal fluid. The
ependyma
separates
CSF from brain tissue.
Recent
sufficient, then the initiator,
or virus, must be eradicated.
Whether the leukemic cells or constant viral reinfection is evidence suggests that this is less of a solid cellular bar
ncr than the others.
the continuing cause of leukemia, the cells, if we trust
animal systems, have the pcwer to continue the disease.
None of these barriers is absolute.
No substance I
1572
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RALL—Experimental
BL
Studies of the Blood-Brain
Barrier
1573
TABLE 1
0 0 D
ENTRY
OF TYPICAL
DRUGS
INTO CEREBROSPINAL
FLUID IN MANa
DrugNonionized,
(mm)Antipyrine
BRAIN
CSF:plasma
for entry
pH 7.4 (%)Liooid solubilitySteady ratioHalf-time
Sulfadiazine
10
0.01High
p-Aminohippurate100
CHART 1.—Equilibrium
via the various
barriers
a Data
know of is absolutely excluded from brain or CSF when
present in the blood. For albumin the ratio is something
substances
Perhaps
is
the entry
through
in small
imperfections
or
these membrane
systems,
or through
in the brain that do not possess the
around
the capillaries,
permeability.
amounts
minute
of such
lesions
in
the few small areas
encircling
glial cells
and do not possess any selective
Compounds
could
enter
into brain
and CSF
through the area postrema,
the subforical
body, and
other such areas.
The characteristics
that determine the entry of com
pounds
into
brain
and CSF
are similar,
and these
will be
treated together.
The available routes of exit from brain
and CSF are different, however, and these will be treated
separately.
The key to the entry of compounds into the
CNS is the solid cellular barriers that must be traversed.
The characteristics
that chemical compounds must possess
to diffuse rapidly through lipoid-like cell membranes are
well
known.
For
easy
penetration
by diffusion
a drug
must be lipoid-soluble and nonionized and should not be
bound to I)lasma proteins or other nondiffusible constit
uents.
The entry of 3 types of substances into CSF will
illustrate this (10, 13). The drugs, their physicochemical
characteristics,
and their entry into CSF in man are shown
in Table 1.
Patients
with
malignant
Blood
diseases
but
was sampled
and CSF was sampled
space
through
no demonstrable
from a peripheral
from the lumbar
an indwelling
catheter.
It is clear that
antipyrine
coneen
for protein
binding
reaches a CSF : plasma concentration
ratio of unity.
This
is typical
drugs.
CSF slowly,
less
lipoid-soluble
and the steady
than
unity.
state
The
Sulfadiazine
CSF : plasma
slowness
of
ratio
entry
is
related to the low degree of lipoid solubility.
The explana
tion of the failures of the CSF : plasma ratio to reach unity
has led to the discovery of interesting ways in which the
concentration
of certain drugs within the CSF and brain
can be altered by altering the physiologic state of the
organism.
Low1
0.260
It is also an example
of how passive
diffusion
can lead to an apparent concentration
gradient across a
membrane.
The key fact necessary to explain the un
equal distribution
of sulfadiazine is that there is a pH
gradient
between
amounts
to about 0.05 pH unit.
CSF
and
blood
(13).
Normally
Sulfadiazine
300
at body
this
is partially
(10).
pH, and the blood-CSF
barrier
is perme
able to nonionized sulfadiazine; it is not permeable to the
ionized drug.
The fraction ionized on each side of the
membrane is determined by the pH on each side. On the
side with the lower pH there will be less total drug (ion
ized and un-ionized) because a greater fraction of the drug
will be nonionized.
This
is illustrated
in Chart
2.
The
CSF and plasma pH were chosen for arithmetic simplicity
and are unrealistic.
By altering the acid-base balance of the animal it is
possible to abolish this gradient, or to accentuate and re
verse it. This offers an opportunity to test this hypothesis
of nonionic diffusion between CSF and blood.
These
studies were performed in dogs, as detailed above.
Aci
dosis and alkalosis induced by primary alterations
in
pCO2 abolish the pH gradient.
Infusion of HC1, however,
lowers blood pH but leaves CSF pH unchanged or raises
it slightly.
Infusion of NaOH raises blood pH, and CSF
pH either falls slightly or is unaffected.'
Table 2 shows
the effects of such pH alterations on the distribution
of
sulfadiazine.
Clearly the distribution
of this weak acid
is profoundly
and
The almost
predictably
complete
p-aminohippurate
can
mechanisms.
virtually
affected
exclusion
be
explained
First,
completely
by
readily.
That
drug
gradients.
on
the
such as
basis
of 3
and most obviously,
ionized
which
pH
of compounds
and
does
they
lipoid-insoluble
body pH and thus cannot diffuse through
diffuse
at
cell membranes
into
the
CSF
is
removed by the fairly rapid bulk flow. The iresence of
bulk flow of CSF is a point of difference between the exit of
compounds from brain and CSF. It is not generally
realized that CSF is produced and returned to the blood
stream
and
of nonionized,
enters
vein,
the CSF rapidly
enters
ionized
are
subarachnoid
Plasma
trations of the drugs were corrected
and plasma water content.
is significantly
from Rall
different
CNS disease were studied.
A constant plasma concen
tration of the drug was established and maintained
by
i.v. infusion.
.0
0.8
of the 3-com
ponent system: blood-brain, blood-CSF, and brain-CSF.
like 400 : 1 .
Low
CSF
at
the rate
through
the brain
so-called
a brisk
rate.
In
an
adult,
CSF
is produced
at
of 0.5 ml/min, and most of this, after flowing
the ventricular system and around the surface of
and cord, exits via either the arachnoid villi, the
valves of the CSF, or out the cranial or spinal
nerve roots (9, 14, 20) . The final ratio of an ionized drug
between blood and CSF is a function
of the relationship
between the net inflow rate of the drug and the outflow
rate of CSF. Also, it is now clear that some organic acids
and bases are actively pumped out of the CSF (8). A
1 CSF
pH
either
shifts
paradoxically
or
is unaffected
for
the
following reasons: CO2 rapidly diffuses between blood and CSF;
bicarbonate does so very slowly. In metabolic acidosis, there
fore,
the
compensatory
CSF pCO2. However,
hyperventilation
CSF bicarbonate,
will
lower
arterial
and
unlike blood bicarbon
ate, will remain unchanged and a slight increase in pH often oc
curs
(16).
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1574
Cancer
CSF
pH
7.5
0%
90 %
IONIZED
@
Vol. 25, October 1965
Research
UN-IONIZED
I
TOTAL DRUG CONC. 200j.eg/ml
@—
MEMBRANE
TOTAL
DRUG
CONC
100.eq/ml
[@
@—
80%
IONIZED
20%
UN-IONIZED
BLOOD pH 6.9
% Un—ionized
Drug
Conc. Total Drug CSF
(2OOj.@g/mI)
Rc@f
CHART 2.—Ilypothetical
TABLE
EFFECT
OF
@HGRADIENTS
SULFADIAZINE
steady-state
distribution
= 2.0
-
CSF(lO)
of sulfadiazine
(pKa 6.5).
TABLE 3
2
ON DISTRIBUTION
BETWEEN
p1 (20)
% Un—ionized
Drug
.%c@s@1 Conc.Total Drug pt
(100.oj/mI)
CSF
DIFFUSION
OF
IN AN AQUEOUS MEDIUM AT 37°C OF INULIN,
SUCROSE, UREA, AND THO
AND PLASMAa
PHCSF:PLAsM.@
OF POINTOF 50%
CONCENTRATION
(mm)lhr4hr24hrTHO
SULFADIAZINEBlOOdCSF•@RATIONormal
SUBSTANCEDIFFUSION
CONSTANT X 10@
(sq cm/sec)DISPLACEMENT
Metabolic
Metabolic
acidosis
alkalosis
Respiratory
acidosis7.39
a Summary
mechanism
1.3
0.6
7.10
7.36
+0.26
7.62
7.34
—0.28
7.04—0.07
7.037.32
0.0150.8
of experiments
similar
to that
tubule exists and probably
0.9
the
This
exhibits
saturation
compounds
CSF
to
the
present
in the proximal
renal
is located in the choroid plexus
blood.
competition
kinetics,
up
air
Like
other
phenomena,
metabolic
arid of course the ability
electrochemical
pumps
stereospecificity,
to move
gradient.
With a considerationi of these 3 types of compounds we
have briefly explored the factors influencing the entry of
drugs into CSF and brain.
If a drug is lipoid-soluble and
un-ionized it is very likely to enter without difficulty.
Partially ionized compounds may be affected by the exist
ence of l)H gradients.
Ionization tends to decrease their
rate of entry and render them susceptible to being flushed
out of the CSF by bulk flow. In addition, an active trans
port mechanism exists which pumps- certain organic dcc
trolytes from CSF to blood. In these latter 2 respects the
situation
with
brain
differs
from
CSF.
Bulk
flow
does
not occur in brain, nor have active transport mechanisms
been demonstrated
which remove compounds from brain
itself.
The relationship between CSF and brain is interesting,
and only now is beginning to be explored.
The ependyma
separating
brain
tissue
1.7
0.7
0.23.2
4.7
3.0
1.615.9
2.4
1.5
0.86.5
11.6
7.4
4.0
in dogs from Rail et al. (13).
of the 4th ventricle. This processmoves certain chemicals
from
Urea
Sucrose
Inulin3.2
from ventricular
CSF and the pia
glia separating brain from subarachnoid
CSF are a less
solid cellular barrier than the others.
Inulin, for example,
is a large lipoid-insoluble
molecule which cannot enter
brain or CSF, but it moves fairly freely from CSF into the
extracellular space of brain (11). Similarly, bromphenol
blue (3) and acetazolamide
(18) are able to enter brain,
presumably the extracellular area from CSF. The con
cept that substances such as these can move freely between
brain and CSF has certain physiologic and pharmacologic
implications over and above those concerned with nutri
tion of neurons and glia.
While the CSF has 2 specialized mechanisms by which
it can be cleared of compounds, brain has none. Consider
a 2-compartment
system in which diffusion alone is the
mechanism
by which a drug moves from 1 compartment
to
the other.
Place a drug which diffuses very slowly across
this membrane in 1 of the compartments.
In a totally
stagnant
system,
a system
in which
there
is no bulk
flow
in either compartment,
this drug, if given time, will move
until there is no electrochemical
gradient between the 2
sides.
So it should
to occur through
active
removal
be in brain.
Bulk flow does not seem
the brain, nor is there evidence for any
of
compounds
from
the
brain.
Experi
mental evidence, however, does indicate that many com
pounds do not—even if given time—equilibrate between
blood and brain.
Must we invoke unproved, ubiquitous,
and nonspecific active removal mechanisms, or are there
other explanations? I would like to suggest that it is feasi
ble for such compounds to diffuse out of the brain sub
stance and into the CSF where they may be removed either
by bulk flow—which is, after all, energy-requiring—or by
active transport.
It is clear that
mum
and other large,
lipoid-insoluble
molecules are free to diffuse into the brain from the CSF.
Although diffusion is a slow process, after 3—4hr the 1st 5
mm of brain tissue adjacent to the CSF will have a concen
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RALL—Experimental
Studies of the Blood-Brain
we have a system
not very dissimilar
from
ENTRY
in the CSF.
One is nonspecific
organic
electrolytes
from
bulk
flow of CSF.
mechanism
the
characteristic
of this steroid.
needed concerning
CSF and brain.
No information
vincristine
into
Clearly
would
suggest
more
information
is
the entry of this and other steroids into
is available
CSF
. howei er, is that
or
concerning
brain.
The
it does not affect
AS A FUNCTION
0.6
2.0
6.40.10
2
4
80.1
a Data
that steroids should enter to a much greater extent, it was
assumed that this reflected the high degree of plasma pro
tein binding
CSF
OF
concentration ms)CSF:
concentration
plasma1 (mM)CSF
Plasma
The
CSF.
physicochemical
INTO
CONCENTRATIONa
0.30
0.50
0.8
that removes weak
What is known concerning the entry of the known anti
leukemic drugs into CSF and brain?
Methotrexate
(MTX) is the best studied, and it is clear that a CSF:
plasma ratio of less than 0.05 is obtained (15, 23, 24).
This is explainable
since MTX
is a lipoid-insoluble,
moderately
strong acid, and is protein-bound
to about
50 % in plasma.
6-Mercaptopurine
(6-MP) also fails
to enter CSF to any great extent (5, 6). This appears
to be the result of the rapid degradation and elimination
of 6-MP rather than a primary
difficulty in penetration.
In experiments
in which massive lethal i.v. infusions
of 6-MP were given to dogs, the CSF : plasma ratios ap
proached 0.5; normally they are much less (6).
The steroids have been studied only to a very limited
extent.
Dr. Walter Oppelt and I have shown that some
what less than 10 % of the plasma concentration of radio
labeled hydrocortisone
enters CSF in dogs or in man.
Since
OF THIOCYANATE
PLASMA
a typical cell with lipoid-like membranes.
Lipoid solubil
ity and nonionization favor entry into a typical cell or the
brain or CSF. Specialized removal mechanisms are found
other is the active transport
1575
TABLE 4
tration about 5 % of that in CSF. Inulin and similar
comj)ounds diffuse across the brain capillaries very slowly,
much more slowly than these compounds can diffuse into
the extracellular space of the brain (Table 3).2
In brief, then,
Barrier
the entry
clinical
of
impression,
meningeal
from
Methylglyoxal-bis-guaiiylhydrazone
appears to enter brain
and CSF only to a very limited extent (7). No data exist
concerning the entry of cyclophosphamide
into brain or
CSF.
The failure of these major anti-leukernic agents to enter
brain and CSF, then, aids in the explanationi of the in
creased interest in meningeal leukemia, both as a clinical
entity and as a therapeutic and pharmacologic problem.
et
a!.
(21).
them some degree of toxic specificity.
Perhaps the protean
toxicity of the nitrosoureas is a reflection of this.
Altering the acid-base state of the body can force drugs
into brain and CSF. Consider a weak acid like metho
trexate.
In a situation with a metabolic acidosis in which
the blood pH is lower than CSF pH, the gradient forcing
this drug into CSF becomes
steeper
and more drug should
enter.
Acetazolamide,
a carbonic anhydra.se inhibitor,
will also tend to lower blood pH ; in addition, it will slow
the rate of CSF production and, therefore, the bulk flow
of CSF. Thus the rate of removal of CSF and of met-ho
trexate is decreased.
This is a delicate situation, however.
These same forces will tend to drive MTX into other cells
and other areas as well. Unusual manifestations
of toxic
ity might
result.
Further,
this
will alkalinize
the
urine
and increase the rate of renal excretion of MTX, and the
whole l)[email protected] of the agent will be changed.
Ex
perimentation
alone
will
show
this
to
be
better
therapy
or
worse.
Some evidence exists that MTX specifically and organic
electrolytes
in general
are actively
removed
from the CSF.
Parenteral administration
of a competing electrolyte might
block the active removal of MTX. Again, the total phar
macology
leukemia.
Streicher
active
might
renal
also
excretion
be changed,
will
be
since
similarly
any
element
blocked
arid
of
l)la.sma
concentrations
arid excretory rate will be altered.
The dose schedule also can influenice the penetration of a
drug into CSF and brain, if the drug is susceptible to active
removal from the CSF. High dosages will saturate the
active
transport
system,
arid
the
over-all
removal
will
If 1 or more of these highly active agents were able to enter
therefore be less. An example is found (21) on the entry
of thiocyanate,
which is actively removed, into the CSF
(Table 4).
Intermittent
dose schedules, or short intensive course
CSF and effectively
schedules,
inges, this problem
eradicate
How can meningeal
facts just presented,
adequate
treatment
leukemic
would hardly
leukemia
cells on the men
exist today.
be treated?
with
proportionally
Given
the
A different
higher
sort of systemic
how can we use them to allow the
of meningeal leukemic cells and other
mia in an attempt
neoplastic cells sequestered within the CNS?
One approach is to find or develop drugs which are
lipoid-soluble and un-ionized.
That this is a promising
field is shown by the nitrosoureas.
It is possible, how
ever, that the ubiquity of their distribution
may deny
increased amounts
hypothermia
(1).
eluded from brain.
2 This
allows
one
to estimate
the
extracellular
space
in brain.
It turns out to be about 10—15%
in normal animals, but interest
ingly it is 5% in dead animals.
This suggests that at death the
neuronal and/or glial cells swell and imbibe the extracellular
water. This may account for the electron microscopic picture of
brain tissue.
brain
barrier.
important,
but
doses,
might
approach
might
utilized
to force compounds
Recent
to allow
studies
have
hypother
past the blood
suggested
that
of penicillin enter brain tissue during
Penicillin, like MTX, is normally cx
This area of research is intriguing and
it is not
yet
ready
for
These are some of the potential
that
be expected
more drug to enter the CNS.
be employed
to increase
practical
application.
pharmacologic
the entry
devices
of drugs
into
CSF and brain.
They are applicable only to certain kinds
of agents, such as weak organic electrolytes, and, in par
ticular, organic acids. In quantitative
terms, they might
not be expected to more than double the CSF : plasma drug
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Cancer Research
1576
Inflow System
Vol. 25, October 1965
TABLE 5
Outflow System
DOSAGE
OF METHOTREXATE
FOR VENTRICULOLUMBAB
Toxic
limitationsLocal
(dog)°Convulsive,
Pressure
determined
by height
of outflow
tube
1 mg/ml in cisternal
CSF (0.1-0.2 mg/mI in yen
tricle)Systemic
dose, 0.5—1.0mg/kg
(man)Tolerated
daysPerfusion
every 4
mg/ml,
concentration0.01—0.02
hrTotal
CHART 3.—Block
concentration
diagram
ratio.
of the
drug
ministration
of ventriculolunibar
Generally
really effective therapy.
The other alternative
cation
a From
ii Cord
this
to the
inadequate
for
of drugs
meninges.
cells
within
administration
the
seems
is administered
The
intrathecal
ad
sac of methotrexate
from
the
brain
subarachnoid
was in
and
space
to be the volume
(17).
the treatment,
(12—iS)
Even
with
meninges.
after
lumbar
in which
the drug
attention
to this,
careful
as with the National
Cancer Institute
just reported
by Dr. Thomas,
fails to eradicate
kemic cells and is only symptomatic.
series
the leu
Rate
Volume
3.75, then 1.5 mI/mm
450ml
Concentration
MTXb
Rate
Volume
the
animal
Pressure
Concent
rat ion
Calculated values
CSF production
Inulin clearance
MTX clearance
a Perfusion
b MTX,
technic
(8) to the leukemic
is simple.
CSF is PumPed from a cannula in 1 location,
lateral
ventricle,
to a cannula
in another
cisterna
magna
diagram
in Chart
operational
pressure
or lumbar
3.
sac.
i.e.,
This
The outflow
characteristics
is low,
of the
below
the
system.
normal
generally
location,
is shown
pressure
Synthetic
in a block
determines
If the
CSF
the
the
the
outflow
pressure,
most
Diseases
procedure.
more widely
distri
buted.
In fact it is possible that water and sonic of the
solutes might move into the brain.
Those constituents,
which can do so, will move across ependyma,
the extracellular space in brain, and exit across the capil
lanes into the blood stream.
Others, such as mum or
methotrexate,
may tend to be concentrated in the super
(ventricular
varying
the inflow rate,
is theoretically
possible
and
cortical)
or the brain.
By
outflow
pressure,
and elevation,
it
to deposit
the drug
very
widely
within the CNS adjacent to the CSF. If an adequate
concentration of the drug is presented, the cells free in the
subarachnoid space will be effectively treated.
The layers
and clumps
of cells will be treated
if time is allowed
for the
226
@g/ml
0.45 ml/min
1.3 mi/mm
1.9 mi/mm
was
done
for
240
mm.
the centrum
of the time
even though
and Blindness
these areas have
Diffusion is slow, however, and
required
can be seen in Table
3.
for a specific compound,
In collaboration with Dr.
Institute of Neurological
and Dr. Henderson
of the National
This
was
a 10-year-old
boy
with
acute
lym
phatic leukemia, who was in systemic remission but had
meningeal leukemia.
The details of the 1)erfusion are
during
will become
@g/ml ; inulin
Cancer Institute, we have performed 6 such perfusions in
3 patients. The 1st patient will be used to illustrate the
given
and the solution
10
Some dosage considerations
MTX, are shown in Table 5.
Edgar Bering of the National
channels,
ficial layers
WITH
methotrexate.
not I)enetrate
of the infused synthetic CSF as well as the normally formed
CSF will appear in the outflow.
As the outflow pressure is
increased, more and more will follow the normal outflow
such as water,
(17).
0.3—1.0mI/mm
125ml
90—iSO
mm H2O
MTX 2.9—4.4pig/mI; inulin 150—206@sg/
ml
some notion
the experimental
prmciple
al.
Outflow
inward diffusion of drug.
In
et
Inflow
perfusion
child.
Rieselbach
VENTRICULOLUMBAR
PERFUSION
IN A 10-YEAR-OLD
Bo@
ACUTE LYMPHOCYT1C LEUKEMIA WITH MENINGEAL
The problem is one of getting the drug in the right place
in the right concentration.
One approach to this that we
have attempted was to adapt the j)rocedure of ventricular
from
and
the direct appli
The reasons for this seem to be the low concentration
of
the drug in many of the crevices and crannies of the sub
arachnoid space. The major factor affecting the distribu
tion
co-workers
TABLE 6
troduced by the group at Memorial Hospital (23, 24) and
this form of treatment
produces excellent symptomatic
control.
However, u.s Dr. Thomas has shown, it fails to
leukemic
and
LEUKEMIAa
is local therapy,
into the lumbar
eradicate
Rail
mg
perfusion.
is
1.2—5ml/min,
for 2—4
dose5—15
NerveRoots
PERFUSION
in Table
6.
He experienced
the perfusion,
It is impossible,
nausea
but otherwise
so far, to estimate
the therapeutic
of these perfusions.
Thus a subarachnoid
an acflve agent offers 1 other approach
eradication of leukemic cells in the CNS.
I have discussed
and
retching
was a.symptomatic.
effects
perfusion with
to the possible
in detail a major area of pharmacologic
asylum.
But it should be clear that there may be other
areas iii which neopla.stic cells may find a sanctuary, such
as the thymus, or the testes, or even neoplastic growths
themselves.
There is an inadequate blood supply in the
interior of large tumors.
It has recently been shown that
there is a limitation to the entry of even tritiated water to
the center of transplanted tumors (21). Dyes slowly enter
and exit from the pericentral area of some tumors, and do
Downloaded from cancerres.aacrjournals.org on June 15, 2017. © 1965 American Association for Cancer Research.
RALL—Experimental
been shown to contain viable cells (4).
it would be to eradicate
Studies of the Blood-Brain
12. Rail,
How unfortunate
system.
1. Baldwin, M., Farrier, R., MacDonald, F., and Ommaya, A. K.
Cerebral I)isposition of Drugs at Low Temperatures. J. Nets
rosurg., 20: 637-46, 1963.
F. K., Harris,
A. It., Berlin,
N. I., and
White, J. Water Exchange in Animal and Human Tumors. J.
Appi.
Physiol.,
16: 181—85,1961.
3. Domek, N. S., Barlow, C. F., and Roth, L. J. An Ontogenetic
Study of Phenobarbitai-C'4
in Cat Brain. J. Pharmacol. Exptl.
Therap.,
150: 285-93,
sues. J. Physiol., 150: 451—62,
1960.
5. Goldacre, R. J., and Sylven, B. On the Access of Blood-borne
to Various
Tumour
Regions.
Brit.
J. Cancer,
16: 306—22,
Ventricular
System.
Life Sci.,
No. 2, pp. 43—48,1962.
13. Rail, D. P., Rieselbach, R. E., Oliverio, V. T., and Morse, E.
E. Pharmacology
of Folic
Acid
Antagonists
as Related
to
Brain and CSF. Cancer Chemotherapy Rept., 16: 187-89, 1962.
14. Rail, D. P., Stabenau,
J. R., and Zubrod, C. G. I)istribution
of Drugs between Blood Cerebrospinal
Fluid: General Meth
15. Rail,
D. P., and Zubrod,
J. Pharmacol.
C. G. Mechanisms
of Drug
Exptl.
Adsorp
tion and Excretion. Ann. Rev. Pharmacoi., 2: 109—28,1962.
16. Rieseibach, H. E., DiChiro, G., Freireich, E. J, and Ball, D.
P. Subarachnoid I)istribution of Drugs after Lumbar In
jection. New Engl. J. Med., £67:1273—78,1962.
17. Rieselbach, R. E., Morse, E. E., Rall, 1). P., Frei, E., III,
and Freireich,
E. J. Intrathecal
Aminopterin
Therapy of Me
ningeal Leukemia. Arch. Internal Med., 111: 620-30, 1963.
between
Spinal
ence to Control
1958.
Fluid
and
Arterial
of Ventilation.
Blood
J. Appl.
with
Relations
Special
Physioi.,
Refer
15: 385—92,
19. Schabel, F. M., Jr., Johnston, T. P., McCaleb, G. S., Mont
gomery,
J. A., Laster,
W. it., and Skipper,
H. E. Experimental
Evaluation of Potential Anticancer Agents. Cancer iles., 23:
1962.
6. Hamilton,
L., and Elion, G. B. Fate of 6-Mercaptopurine
Man. Ann. N. Y. Acad. Sci., 60: 304-14, 1954.
in
7. Loo, T. L., Michael, I%1.,and Rail, D. P. Distribution and Ex
cretion of Certain Purine Antagonists. J. Pharmacol. Exptl.
Therap.,
122: 45A, 1958.
8. Oliverio, V. T., Adamson, R. H., Henderson, E. S., and David
son, J. D. The Distribution,
Excretion and Metabolism of
Methylglyoxal-bis-guanylhydrazone-C'4.
Ibid., 14! : 149-56,
725—33,
1963.
20. Schanker, L. S. Passage of I)rugs across Body Membranes.
Pharmacol. Rev., 14: 501—30,1962.
21. Streicher,
E., Rall, I). P., and Gaskins, J. R. Distribution
of
Thiocyanate
between Plasma and Cerebrospinal
Fluid. Am.
J. Physiol., 2@: 251-54, 1964.
2. Thomas,
ninges:
L. B. Pathology
of Leukemia
in the Brain and Me
Postmortem
Studies of Patients with Acute Leukemia
and of Mice Given Inoculations of L1210 Leukemia. Cancer
1963.
9. Pappenheimer,
J. R., Jordan,
E. F., and Heisey, S. R. Active
Transport of Diodrast and Phenol-sulfonphthalein
from Cere
brospinal Fluid to Blood. Am. J. Physiol., 200: 1—10,
1961.
10. Rail, D. P. Structure and Function of CSF. In: J. F. Hoffman
(ed.), The Cellular Function of Membrane Transport,
269-82.
C. S. Extracellular
18. Robin, E., Whaley, II., and Crump, U. Acid-Base
1959.
4. Feldberg, W., and Fleischauer, K. Penetration of Bromphenol
Blue from the Perfused Cerebral Ventricles in the Brain Tis
Dyes
W. W., and Patlak,
odology and Effect of pH Gradients.
Therap., 125: 185—93,1959.
REFERENCES
J. H., Miliar,
1577
Space of Brain as Determined by Diffusion of Inuiin from the
the cells from the CSF and menin
ges, but leave them in heavily inifitrated lymph nodes or
other areas ! The problems are different in specifics and
in detail, but the general principles described here can be
applied to these areas as well as to the central nervous
2. Bloch,
D. P., Oppelt,
Barrier
Engiewood,
N. J. : Prentice-Hail,
pp.
1964.
11. Rail, D. P., Moore, E., Taylor, N., and Zubrod, C. G. The
Blood-CSF
Barrier
in Man. Arch. Neurol.,
4: 318-22,
1961.
Res.,
25: 1555-1571,
23. Whiteside,
Burchenai,
Manifestations
1965.
J. A., Phillips,
J. H. Intrathecal
of Leukemia.
F. S., Dargeon, H. W., and
Amethopterin
in Neurological
Arch.
Internal.
Med.,
101:
@79—
85, 1958.
24. Wollner, N., Murphy,
@sI.L., and Gordon, C. S. A Study
Intrathecal
Methotrexate.
Proc. Am. Assoc. Cancer lies.,
74,1959.
Downloaded from cancerres.aacrjournals.org on June 15, 2017. © 1965 American Association for Cancer Research.
of
5:
Experimental Studies of the Blood-Brain Barrier
David P. Rall
Cancer Res 1965;25:1572-1577.
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