Download Water content at different skin depths

DERMATOLOGY
MAURICIO GUZMÁN-ALONSO1, TANIA M. CORTAZÁR2
1. Innovation and Development Centre, Belcorp, Tocancipá, Colombia
2. National University of Colombia. Science Faculty. Department of Chemistry,
Bogotá, Colombia
Mauricio Guzmàn-Alonso
Tania M. Cortazar
Water content at different skin depths
and the influence of moisturizing formulations
KEYWORDS: Hydration, skin water content, depths of the skin, SC, epidermis, dermis.
Abstract
Proper hydration is absolutely critical to obtaining healthy skin. Hydration is the most basic consumer
expectation toward a skin care product and is therefore, the most common and functional benefit
promised by the cosmetics industry. Exists a plethora of endogenous and exogenous ingredients, and moisturizing formulations that
contribute to the maintenance of water in the skin, covering various mechanisms and interactions that influence skin functionality and
structure. Currently it is known in detail the skin composition and some of the interactions of its molecules involved in maintaining the
hydration and water flow. This review will describe some aspects of skin hydration, molecules and formulations involved in the
modulation of water content at different skin depths, and briefly will present methodologies used in the evaluation and information
that they provide about the complex process of the skin hydrationand moisturizer influence.
INTRODUCTION
Skin hydration is defined as the water content of the
epidermis and the dermis (1). The inner milieu of our body
consists of about 70% water (2). Approximately 20% of water
present in the body is accumulated in the skin, with 60–70%
of this amount being accumulated in the dermis (3). Water
is important for the structure and mechanical properties of
many proteins and their mutual interactions (4). Functionally,
the amount of water in the skin can be divided into free
and bound water. In healthy skin, most of the water is bound
to macromolecules. The ability of the skin to hold water is
primarily related to the stratum corneum (SC), which plays the
role of barrier to water loss (5). The retention of water in the SC
is dependent mainly on the presence of natural hygroscopic
agents within the corneocytes and the SC intercellular
lipids ordely arranged to form a barrier to transepidermal
water loss (5). The glycosaminoglycan polymer hyaluronan
(HA, hyaluronic acid) provides a scaffold on which sulfated
proteoglycans and matrix proteins are organized. These
supramolecular structures are able to entrap water and ions
to provide skin with hydration and turgor. HA occurs in both
dermis and epidermis, with dermis containing the greater
proportion (6, 7). HA present in the epidermis may play a
role in a epidermal barrier function and SC hydration (5).
Unbound water molecules bind to each other in tetrahedron
form (8). The lack of interaction between water and
surrounding molecules contributes to dry appearance of
skin. Water content can vary depending on vary factors as
skin site, skin depth, body mass index, age, sex, diurnal hour
(9-15), seasons and climates (16).
On the other hand, Hydration is the most basic consumer
expectation toward a skin care product and is therefore,
the most common and functional benefit promised by
the cosmetics industry; at the same time, skin moisturizing
formulations represent a major category of products in the
skin care business (17). Proper hydration is absolutely critical
to obtaining healthy skin (18). Similarly, the occurrence of
healthy skin is linked to a suitable water content and flow
through all layers. Exists a plethora of endogenous and
exogenous molecules that contribute to the maintenance
of water in the skin, covering various mechanisms and
interactions that influence skin functionality and structure (19).
The challenge of formulations and researchers is to adapt the
formulas to the needs of skin hydration and compliance with
user expectations, who expects a high efficacy regardless the
technology used.
In this review will describe some aspects of hydration at
different skin depths, molecules and formulations involved
in the modulation of skin water content, and present
methodologies used in the evaluation and the information
that they provide about the complex process of the skin
hydration and influence for moisturizers.
EPIDERMIS
The epidermis thickness is variable. It had been reported
between 40 - 240 µm thick, depending on the measuring area
and method used (20-22). Water originates in the deeper
epidermal layers and moves upward to hydrate cells in the
outermost skin layer, the stratum corneum (SC). Aquaporins
H&PC Today - Household and Personal Care Today, vol. 11(1) January/February 2016
35
(AQPs), cell membrane bound water channels present in
the epidermis, are essential hydration-regulating elements
controlling cellular water and glycerol transport (23, 24).
AQP3 is the most abundant AQP in the skin and is primarily
expressed in the stratum basale (SB) of skin, with an expression
decreasing towards the stratum granulosum (SG) (25). This
gradient of AQP3 expression correspond to the decreasing
water gradient from the dermis to the SC. Glycerol, thus
present in the outer epidermal layers, binds and hold water,
important for maintaining optimal skin hydration (24). Glycerol
derivatives, as for example glyceryl glucoside, can promote
the expression of AQPs and reduced transepidermal water
loss (23).
The epidermis contains two different levels of water,
separated by the interface between the SG and the SC, (5).
At this point the largest gradient of water in the skin occurs;
on the one hand in the underlying layers the SG (viable
epidermis) the water content is about 70%, while the SC water
content decays between 15 and 30% (2, 26) (Figure 1). This
gradient isolates the SC from the body, helping to conserve
important solutes and water within the viable epidermis.
The presence of a water gradient at the deeper part of the
SC triggers important keratinocyte functions such as the
proteolysis of filaggrin and, consequently, the production
of Natural Moisturizing Factors (NMF) ( 20). This variation in
the water content ocurrs parallel to the increase in SC lipids
secretion. Both of the processes are essential for the SC
hydration and skin barrier function (5). Dehydration of the
upper skin layers increases when the SC water is lost more
quickly than that which is received from the lower layers of
the skin (viable epidermis and dermis) (27), thus affecting the
natural flow of water. The proper functioning of skin barrier
depends largely on its cohesion. Desmosomes, the principal
interkeratinocyte junctions, contribute to the mechanical
strength of the epidermis (28). Corneodesmosomes, the
modified desmosomes of the SC, mediate the strong
intercellular cohesion in the cornified layers that is crucial for
tha physical and chemical barrier function of the epidermis
(29). Other structures within the epidermis intercellular
regulating the water in the epidermis are the Tight Junction
(TJ) proteins (30), which control paracellular permeability (the
diffusion of water and solutes across intercellular spaces).
Warner and colleagues investigated the skin water
content using electron probe analysis, finding this marked
discontinuity in water content at the SC-SG junction,
which identifies this region as the beginning of the primary
barrier that limits water movement (26). This finding was
also performed later by Bielfeldt et al (2), using in vivo
confocal Raman spectroscopy to define the SC border,
further showing that the SC border is located at the depth
at which the NMF content levels off and the slope of the
water profile curve changes (2). In the Figure 1a. it is shown
the semiquantitative water profile obtained across human
skin (26), with percent water expressed as grams of water
per total grams (water plus dry mass) of tissue. The water
profile across the SC increased approximately linearly or
with a slight S-shape. A large discontinuity in water content
occurs at the SC-SG junction. The discontinuity accounts for
approximately half of the water gradient across the tissue.
In the viable tissue, the water content is approximately
constant or slowly increases toward the dermal junction
(26). In the Figure 1b. is shown a water concentration curve
assessed by confocal Raman spectroscopy (2), with water
36
content expressed in g/cm3. From this water profile across
the epidermis the border between SC and SG can be
estimated, due to the steep drop in water concentration
from the inner to the outer side of the SC (2). Water content
drops from approximately 70% at the inner SC to only 30% at
the skin surface, and this slope of the curve becomes flatter
in the SG (2).
STRATUM CORNEUM (SC)
Figure 1. Skin water content profiles.
a. Water profile across human skin with percent water expressed
as grams of water per total grams (water plus dry mass) of tissue.
SC: stratum corneum; GR: stratum granulosum; SP: stratum
spinosum; B: stratum basale.
b. Water concentration curve with water content expressed
in grams/cm3. Graphics modified from references 26 and 2,
respectively.
The inner milieu of our body consists of about 70% water,
while the surrounding air at ambient conditions contains
less than 1% water, so at ambient humidity the air is far from
saturated (2). Water originates in the deeper epidermal
layers and moves upward to hydrate cells in the outermost
skin layer, the stratum corneum (SC), eventually being lost
to evaporation. Then, an evaporation barrier is needed to
maintain body water homeostasis. The SC, with its normally
minute thickness between 10 - 20 µm in most areas of the
body, functions as the main evaporation barrier (2, 20, 31).
Its architecture is the most important factor in water flux and
retention in the skin, and in overall level of moisturization. SC
damage affects the capacity to retain water, which leads
to drying of the skin impairing the barrier function. In the
SC, free water is able to diffuse from the skin to the outer
environment, while bound water is associated with many
molecules, such as filaggrin and other NMF such as amino
acids, pyrrolidone carboxylic acid (PCA), lactic acid, urea,
glucose and mineral ions (32), throughout the epidermal
layers (1). Furthermore, water is inhomogeneously distributed
in the SC (7). Bouwstra and colleges (2003) observed
hydration level in the central part of SC is higher than in
the superficial and deeper cell layers, and water domains
are mainly present within the corneocytes and not in the
intercellular regions. At a very high hydration level (300%
wt/wt), the corneocytes are strongly swollen (except for
deepest cell layers adjacent to the viable epidermis), and
cell thickness increases linearly with the hydration level;
swelling of cells mainly occurs in the direction perpendicular
to the skin surface. At an increased hydration level, the
corneocyte envelope more efficiently surrounds the cell
content compensating for the increased cell volume (7).
SC thickness can increase up to two-fold by hydration for
H&PC Today - household and Personal Care today, vol. 11(1) January/February 2016
few hours (31). It has been observed changes in the SC
water levels during different seasons. The water content
in face skin decreased in autumn, especially near the
eyes and upper-cheek (33). Dry skin in the winter involves
scaling, defects in water holding and barrier functions, and
decreased ceramide (CER) levels in the SC (34).
The SC intercellular space is enriched in lipids organized
into lamellar bilayers. It has been proposed that the
organization of SC lipid bilayers could be stabilized by a
partial interdigitation between the two leaflets (16, 35, 36).
In human SC the major lipids classes are ceramides (CER),
cholesterol (CHOL) and saturated long chain free fatty acids
(FFAs); the ratio between these lipid classes is approximately
equimolar (37), and they are responsible for the permeability
barrier and water holding functions of the epidermis (34).
The CHOL molecules play an important role in the
permeability of SC, since partly immobilize the hydrocarbon
chains of the lipids, making the lipid bilayer less deformable
and thereby decreases the permeability of the bilayer
to small hydrophilic molecules (16). The relative rigid
lipid bilayers of the SC also are characterized by a high
content of unusually long chain CER (38). Each long chain
ceramide species has unique properties that contribute
to SC organization and thereby provide the SC with its
barrier function (39). Levels of total CER and the specific
CER species with sphingoids 6-hydroxy sphingosine (CERNP)
and phytosphingosine (CERNH), are indicators of normal
keratinization, show significant positive correlations with
conductance values and play important roles in maintaining
lamellar stability in the membrane assembly (34, 37, 40).
In dry skin, the level of long chain CERs decreases (41)
and there are changes in composition of CER subtypes
(42). The increase of CER levels plays an important role in
improving and/or preventing dry skin symptoms (34). Some
studies show active molecules (vg. niacinamide, Eucalyptus
extract) could increase the levels of enzymes related to
the anabolism of CERNP and CERNH in keratinocytes, thus
improving SC function (34, 43, 44). Fatty acids, essential
components of natural lipids, determine the physiological
structure and function of the skin. (45).
Depletion of lipids in SC can occur with ageing, cleansing,
environmental conditions or dry skin disorders (33, 34, 46). The
lipid bilayers are targets for influence of moisturizing products
(43). Fourier transform infrared spectroscopy (FTIR) studies
using lipid mixtures containing isolated CER, CHOL and FFAs,
mimicking the lipid composition and organization in SC,
show that some lipophilic moisturizers can interact with SC
lipids, rendering the more densely packed (47) In addition to
the thickness of the bilayer, the packing of the lipids within
a bilayer can be expected to control the overall barrier
properties. Proposed forms of bilayer organization include
orthorhombic, hexagonal and fluid or less rigid bilayers (48).
Among these three forms, orthorhombic represents the most
compact packing with the highest barrier properties and
the fluid form represents the least. Proportions of these may
vary depending upon the relative levels of various lipids
and their chain length in the bilayer (49). SC lipid simulation
studies suggest distinct roles for each lipid species within
the bilayer (16). In experiments conducted by Das et al.
(2009), CER compose a dense bilayer phase, whereas the
smaller, more rigid CHOL molecules serve to secure and
condense the bilayer, thus increasing the lipid density within.
In contrast, FFAs function to relieve the stresses induced by
the dense and rigid CHOL/CER bilayer (16). It is possible that
the shorter chain fatty acids (such as C18) associated with
the fluid phase of the bilayer provide flexibility, whereas
the longer chain fatty acids (>C20) are associated with
the more rigid crystalline phase (50). The stabilization of the
orthorhombic lateral packing of the lipids might reduce the
water loss from the skin, and contribute to the moisturizing
effect of the lipophilic moisturizers (47). On the other hand,
some evaluations of product ranking show increase in
efficacy when lipids are added to the formulations (51),
and recordings of Near Infrared Spectroscopy (NIR) had
showed differences in the regions belonging to CH and NH
groups, rather than purely on the water bands, when skin is
treated with a lipid moisturizer indicating the interaction and
moisturizing effect on the skin (52).
Keratin is the major non-aqueous component of SC
which accounts for 80% of its dry weight (53). Keratin
also is a major factor (together with filaggrin derived free
amino acids) determining SC hydration level and water
holding capacity. The water holding capacity depends
on the structural organization of the corneocyte keratinassociated membrane network in a cubic-like rod-packing
symmetry, with a lipid bilayer between apposed keratin
intermediate filaments. This structure demonstrates the
close lipid association of keratin and the insolubility of
keratin and promotes the reduction in cell volume and
hydration level between SG and SC layers (54). Lipids
and keratins play very important role in formation of
permeability barrier. It is important in the hydration
process of the skin, the SC extracellular matrix, which is
metabolically active, as it changes both structure and
function as it transits to the surface, and contains not
only lipids but also enzymes, other structural proteins, and
antimicrobial peptides that could impact barrier function
and water holding capacity (55).
Hyaluronic acid (HA) present in the epidermis, regulates
keratinocyte differentiation and SC-extracellular lipid
formation required for normal SC structure and epidermal
barrier function, by interacting with its receptor CD44,
on keratinocyte cell surface (56). Xylose, component of
glycosaminoglycans (GAGs), is a keratinocyte HA synthesisstimulating and skin-hydrating agent (57).
DERMIS
The inner layer of the skin, the dermis, is between 1 and 4
mm thick (20), and it consists mainly of connective tissue.
Dermis thickens as it binds more water (58, 59). In the
dermis, the collagen fibers, the interstitial space GAGs
and the proteoglycans, can absorb large quantities of
water (60), determining the intrinsic turgor of youthful
skin. With aging of the skin, the collagen fiber network
is stretched, reduces its absorption capacity and water
retention. Dermal hydration is highly related to the content
and distribution of GAGs. GAGs are widely distributed
throughout the skin. GAGs most often present in human
skin are hyaluronic acid (not attached to a protein core)
and the proteoglycan family of chondroitin sulfates (GAGs
attached to a protein core). GAGs bind up to 1000 times
their volume in water (4). Some conditions influence on
GAGs behavior. As was shown by confocal laser scanning
H&PC Today - household and Personal Care today, vol. 11(1) January/February 2016
37
microscopy, GAGs in photodamaged skin are abnormally
deposited on elastotic material clumped in the papillary
dermis, rather than diffusely scattered as in young skin
(8). This aberrant localization interferes with normal water
binding by GAGs, despite their increased number (4).
Age also leads to increased hydrophobicity and folding
of proteins (vg. collagen, elastin), which in turn, leads to a
decreased interaction of dermis proteins with water. Hence,
in aged skin, water is found in the tetrahedron form, bound
to itself rather than other molecules (4).
INGREDIENTS AND MOSITURIZING FORMULATIONS
Evidence from several clinical and in vitro studies shows
increase in the SC water content due to application of
moisturizing formulations. The use of effective and safe
moisturizers is beneficial in the treatment of dry skin and skin
barrier disorders. Corneocyte morphology and keratinocyte
biology also are targets for moisturizing products (43). The use
of some moisturizers during a week can cause increase in the
area of corneocytes up to 5% (61). When samples of excised
skin treated with moisturizers are visualized by cryoscanning
electron microscopy, the SC appears as a region of swollen
corneocytes trapped between two layers of relatively dry
corneocytes (62). Centrally located corneocytes are more
sensitive to moisturizer application than corneocytes in nonswelling regions, and the change in SC thickness is most
influenced by the change in the thickness of this central
swelling region, where cells swell because much NMF is
available for water retention, while in upper non-swelling
region, for example, NMF is easily lost due to the skin surface’s
frequent contact with water (63). This water distribution
correlates with the NMF distribution in SC (62). Changes after
the application of topical moisturizer product involve the
skin surface by reducing the micro-scales and epidermal
irregularity, as was revealed by reflectance confocal
microscopy (1). Alike, depending of their composition,
moisturizers are able to change the mRNA expression of
certain epidermal genes essential for keratinocyte cycle (vg.
involucrin, transglutaminase, kallikreins) (64).
Likewise, formulations that contribute to the improvement
of the skin hydration at different depths, interact in a
specific way with structure of the skin, and the diversity
of ingredients can provide efficacy through different
mechanisms (65). Vary authors have found that profile
of hydration can change depending on type of
moisturizing formulation (15, 53, 66, 67). And, when water
content averages are compared, the effect of distinct
formulations on the SC could be different at the time (15).
In the same way, it was observed that emollients can
present different mechanisms of hydration (68), and a
good moisturizing performance depends mainly on the
choice of the emollients and can enhanced by choosing
the right emulsifier (69). Moisturizers can improve skin
moisturization but only some formulations improve SC
thickness, water gradients and hydration (70), and this is
due to compositional differences between the products.
For example, niacinamide (nicotinamide, vitamin B3) could
contribute to this effect (70).
With respect to the dermis, there are very few studies that
report a relationship between the change in water content
38
and application of moisturizing products. Mlosek et al (2013)
observed that after the use of a moisturizing cream, they
were obtained statistically significant differences between the
echogenicity of the superior layer of the dermis on the chin
and cheek, suggesting dermis thickening due to formulation
application (71). Likewise, in our recent study, we further note
temporal significant changes in the dielectric constant of
the dermis, to effective skin depths of 500 µm and 1500 µm,
after moisturizing formulations were applied (15), which could
indicate an increase in the dermal water content. We have
not found other studies that show this same. Future studies are
necessary to reinforce these results, trying with other different
available measurement methodologies and/or biochemical
approaches that could see for example some kind of
molecular signalling mechanism that could lead to increased
dermis water content.
On the other hand, the water content at 2500 µm depth not
showed significant changes by any of the formulations used
(15). This is consistent with other researches where they did not
observe any significant differences in the inferior (reticular)
layer of dermis post application of moisturizing cream,
while the superior layer bind water, when skin moisturization
treatments where monitored by high frequency ultrasound
(58, 71). Another study show similar results, where neither
moisturizer use, age, body mass index (BMI) nor hair removal
had any significant effect on the dielectric constant values at
effective skin depth of 2500 µm (13). Moreover, in a long-term
study, the daily performance of massage after moisturizer
application neither substantially promoted the moisturizer
efficacy (72).
Exists a plethora of endogenous and exogenous ingredients
that contribute to the maintenance of water in the skin,
covering various mechanisms and interactions that influence
skin functionality and structure. Moisturizers are based on
occlusive substances, such as petrolatum and dimethicone,
and humectant substances, such as glycerin and urea
(19). According to their chemical nature of the ingredients
can be classified in lipophilic and hydrophilic moisturizers,
and they can show different actions (62). Some hydrophilic
moisturizers could penetrate much more readily than
lipophilic moisturizers, and the latter are abundantly present
in the upper regions of the SC (73, 74). Lipophilic moisturizers
may penetrate into the SC and interact with the SC lipids
to provide an increased barrier to water loss (vg. esters) or
remain on the surface of the skin, thereby preventing water
evaporation from the SC by their occlusive properties (vg.
petrolatum); and hydrophilic moisturizers can be hygroscopic
substances of low molecular weight that could penetrate the
SC, and act as humectants, mimicking the role of NMF (vg.
glycerol, hydroxylethyl urea, mono- or di- saccharides) (75).
Equally there may be differences between moisturizers of the
same type or changes in efficacy when they mixed with other.
For example, glycerol can induce swelling of corneocytes
and formation of intercellular water domains, whereas urea
formulations can result only in the formation of intercellular
water domains (76).
The efficacy of a moisturizer is influenced by factors such as
consumer compliance and skin dryness grade (1, 51). This
point concern partly to the composition of the formulation
and sensorial properties of emollients. Emollient is defined in
reference to the plasticizing and smoothing effect on a rough
H&PC Today - household and Personal Care today, vol. 11(1) January/February 2016
and dry skin surface and they are multifunctional ingredients
supporting multiple formulation claims: skin feel agents,
solvents for numerous actives, permeation enhancers,
gloss or shine control, skin protectants against damaging
enviroment among others (79). The efficacy of a moisturizer
is influenced by factors such as consumer compliance,
skin dryness, skin type and the moisturizer composition (1,
51). There is a direct dependency of skin physiology and
product efficacy. The drier the skin, the higher the increase
of hydration (51). On the other hand, it is noted that an
improvement in skin hydration does not necessarily imply an
improvement in other parameters. For example, an increased
moisturization performance does not necessarily result in
increased skin elasticity and that therefore a combination
of mechanisms had to be influencing what is perceived by
consumers as a positive skin response to emollient application
(68). Long-term use of moisturizers can significantly increase
skin capacitance, independently of dose, and does not
change the mechanical properties or TEWL (77, 78).
CONCLUSIONS
In the course of this review we have detailed some
components involved in maintaining water content
through the depths of the skin. An alteration or unbalance
of a component triggers a skin disorder that leads to the
generation of dry skin, Similarly the absence or lack of water
retention indicates an impaired barrier function of the skin.
Greater interaction between evaluation methods and
mechanisms is required to achieve a greater understanding
of the regulation and interaction of water within the skin. The
correlations between in vivo and molecular results is important
for the development new targets and actives for skin care.
Moisturizing formulations are widely used to combat dry
skin. These formulations contain moisturizing agents that
act by different mechanisms and interact in a specific way
and change the flow of water at the different skin layers.
The necessity of evaluate different moisturizers through
their capacity to increase the skin hydration level on
different depths arises to obtain objective information in the
mechanisms and offers accordance with consumer needs.
Is necessary deepen in the interaction of formulations with
different skin layers and influence on the water content. In
the dermis has not reported study enough for the influence
of moisturizars that confirm changes in the water content
and biochemical pathways. One single evaluation method
is not sufficient in order to fully understand the hydration
mechanisms, requiring a combination of in vitro and
bioengineering techniques in vivo to evaluate the impact
and the mechanisms of ingredients and formulations in the
maintenance and recovery of skin hydration.
The hydration skin research has come a long way in
identifying key issues and findings that have improved
moisturizing products; however there is still a longer way,
where always expected something incredible that is waiting
to be discovered.
REFERENCES
1.
2.
3.
Table 1. Methods for measurement of skin hydration.
METHODOLOGIES FOR ASSESSMENT THE SKIN WATER CONTENT
4.
5.
6.
Many approaches exist to noninvasively determine the water
content of the skin (4). One single method is not sufficient in
order to fully understand the hydration mechanisms, requiring
a combination of in vitro and bioengineering techniques
in vivo to evaluate the impact and the mechanisms of
ingredients and formulations in the maintenance and
recovery of skin hydration (79).
Table 1 shows the main methodologies to measure the water
content in the skin and the information that each provides.
7.
8.
Manfredini, M., Mazzaglia, G., Ciardo, S., et al.. Does skin hydration
influence keratinocyte biology? In vivo evaluation of microscopic
skin changes induced by moisturizers by means of Reflectance
Confocal Microscopy. Skin Res Technol, 2013; 19: 299–307.
Bielfeldt, S., Schoder, V., Ely, U., et al. Assessment of Human
Stratum Corneum Thickness and its Barrier Properties by In Vivo
Confocal Raman Spectroscopy. IFSCC Magazine, 2009, 12, 1.
Kacalak-Rzepka, A., Bielecka-Grzela, S., Klimowicz, A., et al. Dry
skin as a dermatological and cosmetic problem. Ann Acad Med
Stetin, 2008, 54(3): 54–57.
Waller, J.M., Maibach, H.I. Age and skin structure and function, a
quantitative approach (II): protein, glycosaminoglycan, water, and
lipid content and structure. Skin Res Technol, 2006, 12(3):145-154.
Verdier-Sévrain, S., Frédéric Bonté, F. Skin hydration: a review on its
molecular mechanisms. J Cosmet Dermatol,2007, 6, 75–82.
Egawa, M, Tagami, H., Comparison of the depth profiles of
water and water-binding substances in the stratum corneum
determined in vivo by Raman spectroscopy between the cheek
and volar forearm skin: effects of age, seasonal changes and
artificial forced hydration. Br J Dermatol, 2008, 158(2):251-60.
Bouwstra, J.A., de Graaff, A., Gooris G,S., et al. Water distribution
and related morphology in human stratum corneum at different
hydration levels. J Invest Dermatol, 2003;120(5):750-758.
Gniadecka, M., Nielsen, O.F., Wessel, S., et al. Water and protein
structure in photoaged and chronically aged skin. J Invest
Dermatol, 1998, 111(6):1129-1133.
H&PC Today - household and Personal Care today, vol. 11(1) January/February 2016
39
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
Mayrovitz, H.N. Local tissue water assessed by measuring
forearm skin dielectric constant: dependence on measurement
depth, age and body mass index. Skin Res Technol 2010; 16:
16–22.
Mayrovitz, H.N, Carson, S., Luis, M. Male–female differences in
forearm skin tissue dielectric constant. Clin Physiol Funct Imaging,
2010; 30: 328–332.
Mayrovitz, H.N, Luis, M. Spatial variations in forearm skin tissue
dielectric constant. Skin Res Technol, 2010, 16: 438–443.
Nakagawa, N., Matsumoto, M., Sakai, S. In vivo measurement
of the water content in the dermis by Confocal Raman
spectroscopy. Skin Res Technol, 2010, 16: 137–141.
Jensen, M.R, Birkballe, S., Nørregaard, S., et al. Validity and
interobserver agreement of lower extremity local tissue water
measurements in healthy women using tissue dielectric constant.
Clin Physiol Funct Imaging, 2012, 32(4):317-322.
Luebberding, S., Krueger, N., Kerscher, M. Skin physiology in men
and women: in vivo evaluation of 300 people including TEWL, SC
hydration, sebumcontent and skin surface pH. Int J Cosmet Sci,
2013, 35(5):477-483.
Cortázar, T.M, Guzmán-Alonso, M., Novoa, H., et al. Comparative
study of temporary effect on the water content at different
depths of the skin by hot and cold moisturizing formulations. Skin
Res Technol, 2015, 21(3):265-271.
Das, C., Noro, M.G., Olmsted, P.D. Simulation studies of stratum
corneum lipid mixtures. Biophys J, 2009 . 97: 1941–1951.
Jiang, Z., DeLaCruz, J. Appearance benefits of skin moisturization.
Skin Res Technol, 2011, 17: 51–55.
Simion, F.A., Abrutyn, E.S., Draelos, Z.D. Ability of moisturizers to
reduce dry skin and irritation and to prevent their return. J Cosmet
Sci, 2005, 56(6):427-444.
Draelos, Z.D. Active Agents in Common Skin Care Products. Plastic
and Reconstructive Surgery, 2010, 125(2):719-724.
Caspers, P.J., Lucassen, G.W., Puppels, G.J. Combined In Vivo
Confocal Raman Spectroscopy and Confocal Microscopy of
Fl
C He
6
2
O
114
W
8
M
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
Human Skin. Biophys J, 2003, 85, 572–580.
Vyas, S., Meyerle, J., Burlina, P. Non-invasive estimation of skin
thickness from hyperspectral imaging and validation using
echography. Computers Biol Med 2015, 57: 173–181
Sandby Moller, J., Poulsen, T, Wulf, HC. Epidermal thickness at
different body sites: relationship to age, gender, pigmentation,
blood content, skin type and smoking habits. Acta Derm
Venereol, 2003: 83 (6): 410-3.
Schrader, A., Siefken, W., Kueper, T. et al. Effects of glyceryl
glucoside on AQP3 expression, barrier function and hydration of
human skin. Skin Pharmacol Physiol, 2012, 25(4):192-199.
Draelos, Z. Aquaporins. An introduction to a key factor in the
mechanism of skin hydration. In: Skin structure and function.
Translation of research to patient care, 2012, 5(7): 53-56.
Sougrat, R., Morand, M., Gondran, C., Barré, P., Functional
expression of AQP3 in human skin epidermis and reconstructed
epidermis. J Invest Dermatol, 2002, 118(4): 678–685.
Warner, R.R., Myers, M.C., Taylor, D.A. Electron probe analysis of
human skin: determination of the water concentration profile. J
Invest Dermatol, 1988, 90: 218–224.
A Short Textbook of Cosmetology. In: KF De Polo, ed. Moisturizers
and Humectants, 1st Edn. Verlag für chemische Industrie, H
Ziolkowsky GmbH, Augsburg/Germany; 1998: pp. 134–45.
Haftek, M., Callejon S., Sandjeu, Y., Compartmentalization of the
human stratum corneum by persistent tight junction-like structures.
Exp Dermatol, 2011, 20(8): 617-621.
Jonca, N., Guerrin, M., Hadjiolova, K., Corneodesmosin, a
component of epidermal corneocyte desmosomes, displays
homophilic adhesive properties. J Biol Chem, 2002, 277(7): 50245029.
Brandner, J., Kief, S., Wladykowski, E., Tight junction proteins in the
skin. Skin Pharmacol Physiol, 2006, 19:71–77.
Readers interested in a full list of references are invited to visit our
website at www.teknoscienze.com
74
Is
53
Tr
21
Y
for Industrial Applications
8th Symposium on Continuous Flow Reactor Technology
for Industrial Applications
SAVE THE DATE
JOIN US IN DELFT (NL)
November 8-9-10, 2016
1 day practical session (Nov 8th) plus 2 days conference (Nov 9th -10th)
TU Delft Process Technology Institute (DPTI)
Become part of Flow Chemistry Universe
Register to attend at: www.flowchemistrytks.com/how-to-register.html
Interested in exhibiting or sponsoring?
Contact Simona Rivarollo at [email protected]
www.flochemistrytks.com is created by
, the publisher of
ANTI-AGEING SKIN CARE
7-8 JUNE
2016
CONFERENCE 2016
New approaches to prevention and treatment
Royal College of
Physicians, London, UK
The Anti-Ageing Skin Care conference will focus on new approaches to
prevention and treatment. It will discuss the changes from anti-wrinkle
and moisturising creams to the effective contemporary formulations
of today and the future that have an effect beyond that of the stratum
corneum.
5th in the series of
biennial international
Skin Care Conferences
Over the two days of the conference expert speakers will present and discuss topics related
to skin ageing mechanisms, treatment and prevention. They will explore how regulators
view these advances in anti-ageing skin care technologies and associated effectiveness
claims will be discussed in an open forum.
Sessions
Tuesday 7 June
Wednesday 8 June
Session 1: Skin ageing processes and causes of premature skin ageing
Session 3: Advertising and claim support
for anti-ageing skin care products
KEYNOTE - Skin ageing beyond UV: basic mechanisms and
clinical implications
Prof Jean Krutmann, Leibniz Research Institute for Environmental
Medicine, Germany
Smoothing the way from script to screen - getting your
skin care ads to air
Niamh McGuiness, Clearcast, UK
Oxidative stress and ageing - the effects of environmental pollution,
sunlight and diet
Prof Mark Birch-Machin, Newcastle University, UK
Supporting breakthrough anti-ageing skin care claims
Dr Jack Ferguson, Skinnovation Ltd, UK
The unique microenvironmment of the ageing human adult scalp
Prof Des Tobin, Centre for Skin Sciences, UK
Session 4: Assessment and delivery of
anti-ageing skin care benefits
Premature skin ageing induced by air pollution: new in vitro insights
approaching realistic conditions
Prof Imke Meyer, Symrise, France
Anti-ageing skin care strategies
Prof Paul Matts, Procter & Gamble, UK
Session 2: New technologies and treatments for premature skin ageing
KEYNOTE - Understanding ageing, its limits and possibilities
Prof Suresh Rattan, Aarhus University, Denmark
The influence of age, ethnicity and anatomical site on skin
mechanics and composition
Dr Michael Sherratt, University of Manchester, UK
In vivo methods to evaluate anti-photo ageing and anti-pollution
efficacy claims of cosmetic products
Dr Stephan Bielfeldt, proDERM, Germany
Benefits of topical Q10 treatment on human skin
Dr Anja Knott, Beiersdorf, Germany
Microarray analysis of skin ageing
Marta Hlobilová, Contipro, Czech Republic
Optical Coherence Tomography (OCT) - a new tool for quantification
of skin ageing
Jon Holmes, Michelson Diagnostics Ltd, UK
A novel mechanism to prevent solar-light induced oxidative stress
Varun Mathur, The HallStar Company, USA
Ex vivo evaluation of efficacy of topical skin formulations
Ardeshir Bayat, Science of Skin, UK
A novel active ingredient induces a beneficial dermal remodelling,
leading to clinical improvement on photoaged skin
Alain Mavon, Oriflame, Sweden
Programme co-ordinator: Dr Jack Ferguson, Skinnovation Ltd, UK
More speakers to be announced shortly
Delegates will be professionals working and interested in the skin care product sector. In particular skin care formulation chemists and development scientists,
product evaluators, clinical trial co-ordinators, regulatory professionals, senior managers in skin care development, marketing/sales and dermatologists.
For booking information
go to www.summit-events.com
Conference co-sponsored by:
Or contact Summit Events Ltd,
20 Grosvenor Place,
London, SW1X 7HN
Exhibitors:
Tel:
+44 (0)20 7828 2278
Fax:
+44 (0)20 7235 3067
Email: [email protected]