Stratum corneum hydration

RO Potts. Stratum corneum hydration Experimental techniques and interpretation of results. J Soc Cosmet Chem 37 9-33, 1986. 

Hydration of the stratum corneum Hydration enhances the drug s solubility in and mobility through the skin (and its absorption) as much as tenfold. Hydration is usually achieved by using an occlusive vehicle or covering the treated skin with impermeable plastic film. 

Ma T, Kara M, Sougrat R, Verbavatz JM, Verkman AS (2002) Impaired stratum corneum hydration in mice lacking epidermal water channel aquaporin-3. J Biol Chem 277 17147-17153 Maeda N, Funahashi T, Hibuse T, Nagasawa A, Kishida K, Kuriyama H, Nakamura T, Kihara S, Shimomura I, Matsuzawa Y (2004) Adaptation to fasting by glycerol transport through aquaporin 7 in adipose tissue. Proc Natl Acad Sci USA 101 17801-17806... 

As an emollient, squalene is expected to increase skin hydration due to skin surface occlusions. In addition, squalene is a substance believed to maintain moisture in the stratum corneum. Novel substitutes were researched for vernix caseosa which is a reported highly efficient barrier cream for facilitating stratum corneum hydration for barrier-deficient skins. For this purpose, various lipid fractions were mixed with squalene, triglycerides, cholesterol, ceramides, and fatty acids to produce a mixture that can generate similar compositions of vernix caseosa (Rissmann et ah,... 

Horii, I., Nakayama, Y., Obata, M., and Tagami, H. Stratum corneum hydration and amino acid content in xerotic skin. Br. J. Dermatol. 121 587-592 (1989). 

Wilhelm, K.P., Cua, A.B., Wolff, H.H., and Maibach, H.I. (1993) Surfactant-induced stratum corneum hydration in vivo prediction of the irritation potential of anionic surfactants. J. Invest. Dermatol. 101 310-315. 

Glycerol is effective in enhancing hydration of the stratum corneum in dry skin.29 Recently it has been shown that the epidermal water/glycerol transporter aquaporin-3 in deficient mice leads to severely impaired stratum corneum hydration.9 In these mice, stratum corneum glycerol content was reduced threefold. And it was shown that glycerol replacement corrects the defects in these mice.30 However, it has not yet been published whether changes in the aquaporin-3 transporter occur in human dry skin or in aged dry skin. 

Yosipovitch, G., Reis, J., Tur, E. et al. Sweat secretion, stratum corneum hydration, small nerve function and pruritus in patients with advanced chronic renal failure. Br. J. Dermatol. 133, 561-564 (1995). 

Dithranol in combination with urea is widely used in psoriasis to improve the clinical efficacy, to minimize the dithranol concentration, to achieve the desired effect, to shorten the contact, to get a better hydration of the stratum corneum, and to decrease the proliferation rate of the keratinocytes. Gabard and Bieli showed an increased keratolytical effect of salicylic acid by adding 10% urea.54 Hagemann and Proksch55 showed in 10 patients with psoriasis under a 2-week treatment with a 10% urea ointment increased stratum corneum hydration, a small decrease in TEWL, a reduction in epidermal thickness (-29%), and a decreased epidermal proliferation (-51%). The altered expression of involucrin and cytokeratins as marker for epidermal proliferation was partially reversed.55... 

Fluhr, J.W. et al., Impact of anatomical location on barrier recovery, surface pH and stratum corneum hydration after acute barrier disruption, Br. J. Dermatol., 146, 770, 2002. 

Wilhelm, K.P. et al., Skin aging. Effect on transepidermal water loss, stratum corneum hydration, skin surface pH, and casual sebum content, Arch. Dermatol., 127, 1806, 1991. 

Gfatter, R. et al., Effects of soap and detergents on skin surface pH, stratum corneum hydration and fat content in infants, Dermatology, 195, 258, 1997. 

Most recently, Nakagawya et al.34 demonstrated that topical application of potassium lactate restored stratum corneum hydration after NMF extraction and exhibited a significantly higher restorative effect than sodium lactate. The authors speculate that this is due to the structure-destructive properties of the potassium ion and may influence hydrogen bonding in the keratin matrix. 

Fluhr, J.W. et al. Glycerol regulates stratum corneum hydration in sebaceous gland deficient (Asebia) mice, J. Invest. Dermatol., 120, 728, 2003. 

FIGURE 20.3 Only a mild, but significant increase of stratum corneum hydration, measured by capacitance was monitored. 

FIGURE 20.4 Deeper effects of glycerol on stratum corneum hydration could be ruled out by assessing the indirect hydration related mechanical parameters of deeper parts of the epidermis, namely the total extensibility (Uf) [Panel a] and the elasticity (Ua/Uf) [Panel b]. 

Ma, T., Hara, M., Sougrat, R. et al. Impaired stratum corneum hydration in mice lacking epidermal water channel aquaporin-3. J. Biol. Chem. 2002, 277 17147-53. 

Fluhr, J., Gloor, M., Lazzerini, S. etal. Comparative study of five instruments measuring stratum corneum hydration (Corneometer CM 820 and CM 825, Skicon 200, Nova DPM 9003, DermaLab). Part I. In vitro. Skin Res. Technol. 1999, 5 161-70. 

These two observations suggest that the uptake of a topically applied gel-state PC matrix alters the biosensor role of the stratum corneum. It results in an elevation of stratum corneum hydration, makes the lipid barrier less rigid and the lipid mixture more polar. This knowledge is relevant for the treatment of dermatitis and dry skin, the conditions in which stratum corneum is less hydrated, less capable of binding water, and abnormally rigid. 

In a hemiface trial in humans 5% vitamin E reduced rhytides, skin roughness, length of facial lines, and depth of wrinkles more than vehicle.68 Topical tocopherol acetate was also shown to significantly increase stratum corneum hydration in human volunteers with additionally enhancing the water-binding capacity as compared to vehicle. The optimum concentration for these effects was 5% tocopherol acetate.69... 

Topical dexpanthenol, a stable alcoholic analog of pantothenic acid with good skin penetration, acts like a moisturizer, improves stratum corneum hydration, reduces transepidermal water loss, and maintains skin softness and elasticity. In wound-healing activation of fibroblast proliferation has been observed in vitro and in vivo with dexpanthenol concomitantly with increased elastic and solid tissue regeneration. In skin irritation pretreatment with dexpanthenol resulted in less damage to the stratum corneum barrier, while adjuvant treatment improved the symptoms of dryness, roughness, scaling pruritus, erythema, and erosions considerably. The topical application is well-tolerated with a minimal risk of skin irritation or sensitization.129-132... 

Gehring, W., Fluhr, J., and Gloor, M., Influence of vitamin E acetate on stratum corneum hydration, Arzneimittelforschung, 48, 772, 1998. 

Gehring, W. and Gloor, M., Effect of topically applied dexpanthenol on epidermal barrier function and stratum corneum hydration. Results of a human in vivo study, Arzneimittelforschung, 50, 659, 2000. 

Berardesca, E. EEMCO guidance for the assessment of stratum corneum hydration electrical methods. Skin Res. Technol. 1997 3 126-132. 

Yosipovitch, G. Xiong, G.L. Haus, E. Sackett-Lundeen, L. Ashkenazi, I. Maibach, H.I. Time-dependent variations of the skin barrier function in humans transepidermal water loss, stratum corneum, hydration, skin surface pH, and skin temperature. J. Invest. Dermatol. 1998,110, 20-23. 

Martinsen 0G, Grimnes S. 2001. Facts and myths about electrical measurement of stratum corneum hydration state. Dermatology, 202,87-89. 

Stratum corneum hydration is essential for proper function and appearance of the skin. 

The moisture content can be measured in vitro by means of gravimetry or electron microscopy, or by magnetic resonance techniques in vivo. The resolution of the latter technique is, however, currently not sufficiently high to enable isolated measurements on the stratum corneum. Compared with these techniques, assessment of stratum corneum hydration by means of electrical measurements (susceptance) represents an important reduction in instrumental cost and complexity. 

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