Hydration State Of Stratum Corneum Research Articles

Skin dryness in apparently healthy human skin is associated with decreased expression of bleomycin hydrolase in the stratum corneum.

Maintenance of water balance in the stratum corneum (SC) is determined by the content of intercellular lipids and natural moisturizing factors (NMFs) in corneocytes. To investigate the association between the NMFs and (pro)filaggrin and the proteases responsible for the processing of (pro)filaggrin to NMFs in the SC of hydrated and dry skin areas of healthy human subjects. The SC hydration state and the transepidermal water loss (TEWL) were measured using a Corneometer and a Tewameter, respectively. Proteases, (pro)filaggrin and NMFs were extracted from SC samples obtained by tape-stripping of the tested skin. Expression levels of (pro)filaggrin were determined by dot blotting and western blotting, and total NMFs by ultra-high performance liquid chromatography. Expression of the proteases caspase-14, calpain-1 and bleomycin hydrolase was measured by western blotting. The levels of (pro)filaggrin were not significantly different between hydrated and dry skin, whereas the level of total NMFs was significantly reduced in dry skin. A negative correlation between (pro)filaggrin and NMFs was found in dry skin (Pearson correlation coefficient r=-0.57, *P<0.05). Bleomycin hydrolase expression was significantly decreased in the SC of dry skin. These results suggest that the low hydration state of dry skin may be due to the reduction in (pro)filaggrin degradation caused by decreased bleomycin hydrolase expression.

Sweat constitutes several natural moisturizing factors, lactate, urea, sodium, and potassium

BackgroundAmino acids (AAs) play important roles in maintaining an optimal hydration state of stratum corneum (SC) as a natural moisturizing factor (NMF). Recently, however, we have reported that lactate and potassium significantly affect the hydration state of SC. ObjectiveTo explore the source of lactate and potassium in SC, we compared the concentration of various NMFs such as AAs, pyrrolidone carbonic acid (PCA), lactate, sodium, and potassium in SC between anhidrotic and adjacent hidrotic areas of patients with acquired idiopathic generalized anhidrosis or segmental anhidrosis. MethodsWe examined 13 anhidrotic areas and the adjacent hidrotic skin of 10 different patients. We first determined anhidrotic and hidrotic areas of each patient by the iodine starch method and examined the hydration state of SC by measuring the high-frequency conductance. Then we obtained SC by tape stripping and measured the content of AAs, PCA, lactate, urea, sodium, and potassium in SC obtained from the anhidrotic and hidrotic areas. We examined the effect of increased insensible perspiration on the SC hydration and the concentrations of NMFs. ResultsThe SC of anhidrotic areas showed significantly low hydration. Among NMFs, lactate, urea, sodium, and potassium were significantly decreased in the SC of anhidrotic areas, while AAs and PCA were not significantly different between hidrotic and anhidrotic areas. Increased insensible perspiration increased SC hydration as well as NMFs other than AAs and PCA. ConclusionSweat constitutes lactate, urea, sodium, and potassium in NMFs and plays a crucial role in maintaining the physiological hydration state of SC.

Evaluation of skin surface hydration state and barrier function of stratum corneum of dorsa of hands and heels treated with PROTECT X2 skin protective cream

Skin roughness is a term commonly used in Japan to describe a poor skin condition related to a rough and dry skin surface that develops as a result of various damaging effects from the environment or skin inflammation. Recovery from skin roughness requires skin care for a long period, thus it is important to prevent development of such skin changes. PROTECT X2 contains agents used for a protective covering of the skin from frequent hand washing or use of alcohol-based disinfectants. These unique components are also thought to be effective to treat skin roughness of the dorsa of the hands and heels. In the present study, we evaluated the effectiveness of PROTECT X2 to increase skin surface hydration state, as well as enhance the barrier function of the stratum corneum of the dorsa of the hands and heels in elderly individuals. A total of 8 elderly subjects and their caretakers without any skin diseases participated in the study. They applied PROTECT X2 by themselves to the dorsum area of 1 hand and heel 3 to 5 times daily for 1 month, while the opposite sides were left untreated. We measured stratum corneum (SC) hydration and transepidermal water loss (TEWL) before beginning treatment, then 1 week and 1 month after the start of treatment to compare between the treated and untreated skin. SC hydration state after applications of PROTECT X2 was 1.5- to 3.0-fold higher than that of the untreated skin in the dorsa of both hands and heels, indicating that the moisturizing ingredients accompanied by water were replenished in those areas where the cream was applied. Also, TEWL in the dorsum of the hands was 17.0-27.9% lower on the treated side, indicating improvement in SC barrier function. On the basis of these findings, we concluded that PROTECT X2 enhances water-holding in the SC and aids the barrier function of the skin in the dorsum of the hands. In addition, we consider that this formulation is useful for not only protecting the hands from the effects of such agents as detergents and alcohol-based disinfectants, but also for protecting heel skin covered by a thick SC from dry and cold conditions such as those encountered in winter. However, since the SC in that area is much thicker than that of the hands, the barrier function was not significantly improved within 1 month of daily treatments.

A neutron-diffraction study of the effect of hydration on stratum corneum structure

The primary barrier to transdermal diffusion resides in the stratum corneum (SC), the thin outermost layer of the skin. The SC hydration state is one of the most important factors that determine the rate of percutaneous permeability. Despite its great importance, the actual mechanism of water–SC interaction is yet unresolved. In the present work we employ the membrane neutron diffraction method, aiming to reveal structural details of porcine SC and ultimately enable the localization of water molecules in the two phases of the tissue.

The Predilection Sites for Chronic Atopic Dermatitis Do Not Show Any Special Functional Uniqueness of the Stratum corneum

The functional deficiencies of the stratum corneum (SC) have been well documented in the skin of atopic dermatitis (AD) patients. AD tends to affect certain predilection areas chronically such as the face, neck and the flexural folds of the extremities. From the paucity of the information about the functional characteristics of the SC in such skin areas, we conducted biophysical measurements at the predilection sites of AD, i.e. the cheek, anterior surface of the neck, nape, antecubital fossa and popliteal fossa and relatively uninvolved sites such as the elbow, mid volar forearm, knee and mid calf in 34 AD patients and in 40 normal individuals. Reflecting the great interlocation variations in the SC noted even in the normal individuals, we found location-dependent as well as severity-dependent changes of SC function in the AD patients. Thus, the values of transepidermal water loss (TEWL) obtained on the cheek and, unexpectedly, the elbow were quite high, whereas those on the poplieal fossa were very low; even those values recorded on the lesional skin of the latter of the AD patients were significantly lower than those of the cheek of normal healthy individuals (p < 0.05). Moreover, the TEWL values measured at the nonlesional skin of AD patients were much closer to those of the normal healthy skin than to those of the lesional skin in most areas. Similarly, the SC hydration state that is influenced by the amount of skin surface lipids showed prominent location-dependent changes in addition to a severity-dependent change. It was much higher even in the lesional skin of the face and neck than in the normal skin of the extensor surface of the limbs. The corneocyte size, which inversely correlates with the turnover rate of the SC, was larger even on the lesional skin of the extremities than that of the normal cheek. It is only in skin surface pH that such location dependency was not demonstrable; it uniformly revealed higher values in the lesional and nonlesional skin of AD patients regardless of the sites. From these comparative data obtained at the predilection sites and relatively unaffected sites of AD, we think that those functional abnormalities of the SC reported in AD patients simply reflect the severity of underlying inflammatory changes rather than inherently defective SC functions.

Pruritus and Hydration State of Stratum corneum in Hemodialysis Patients

Background: Xerosis is the most frequent cutaneous manifestation in hemodialysis (HD) patients, but the association between dry skin and pruritus remains to be clarified. Since the skin surface hygrometer can detect the changes of water content in the stratum corneum more sensitively, we re-examined the relationship between the severity of pruritus and water content in dialysis patients. Methods: Fifty patients who had been undergoing regular HD were examined for the degree of pruritus by clinical grading. Water contents in the stratum corneum at volar forearm and lower leg were assessed by measurement of high-frequency conductance using a skin surface hygrometer both at pre- and postdialysis. Results: Thirty-seven (74%) of dialysis patients complained of pruritus. High-frequency conductance values were significantly lower in HD patients compared to those of age-matched control subjects (n = 13) both at forearm (35.1 ± 3.0 vs. 73.3 ± 10.4 µS, p < 0.01) and lower leg (14.2 ± 1.1 vs. 52.4 ± 7.5 µS, p < 0.01). There was no relationship between the severity of pruritus and age, gender, HD duration, underlying renal disease, or removing fluid volume. A significant reduction of itching score was found in patients using polysulfone membrane. A single HD session using cellulose triacetate or polysulfone membrane significantly increased water content both at forearm and lower leg (p < 0.05). However, the degree of pruritus did not correlate with the skin water content both at the beginning and the end of HD session, respectively. Conclusion: It follows from these findings that water content in the stratum corneum was reduced in HD patients, but did not correlate with the severity of pruritus.

Comparative study of five instruments measuring stratum corneum hydration (Corneometer CM 820 and CM 825, Skicon 200, Nova DPM 9003, DermaLab). Part II. In vivo

Background/aims: The hydration state of stratum corneum can be measured with different instruments. In the present study, five instruments were compared under different experimental in vivo conditions: Corneometer CM 820 and CM 825 (both capacitance based), Skicon 200 (conductance), Nova DPM (impedance based capacitance) and DermaLab (capacitance).Methods: Seven anatomical sites were tested, a sorption‐de‐sorption test (SDT) and a moisture accumulation test (MAT) were performed. Different hydration states were created on the volar forearms by occluded application of an oil‐in‐water (o/w) emulsion, glycerol and urea containing oil‐in‐water (o/w) emulsion, an untreated control site and a site after lipid extraction with acetone. Measurements were performed 15 min after removal of occlusion.Results: The coefficient of variation for CM 820 ranged between 9.3% and 23.7%; for CM 825 between 14.9% and 36.8%; for Skicon 200 between 53.0% and 167.3%; for Nova DPM between 36.4% and 95.8%; for DermaLab between 23.6% and 45.6%. All devices showed a highly significant correlation (P&lt;0.0001) with a high Spearman coefficient r ranging between 0.7928 and 0.9358.Conclusions: CM 820 and CM 825 seem to differentiate more precisely than Nova DPM, Skicon 200 and DermaLab in dry conditions according to previous findings, i.e., that conductance measurements might be more sensitive for hydrated skin and capacitance measurements might be more sensitive for dry skin conditions. The CM 825, the Skicon 200 and the Nova DPM are suitable for dynamic measurements of hydration parameters of the stratum corneum.

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

Background/aims: The hydration state of stratum corneum can be measured with different instruments. In the present study, five instruments were compared under different experimental in vitro conditions: Corneometer CM 820 and CM 825, Skicon 200, Nova DPM and DermaLab.Methods: A sorption‐desorption test, measurements on different filters and with liquids with different dielectric constants, measurement‐depth analysis and measurements on different agar plates were performed.Results: Good correlation between the values of the five instruments and μl (sorption test: varying from r= 0.8249 to r= 0.9635) and time (desorption test: correlation varying from r= 0.7615 to r=0.9909) could be demonstrated. A high Spearman correlation coefficient (r) could be proven for dielectric constant (dc)/CM 820 (r=0.9333), dc/CM 825 (r=0.9833) and dc/Nova DPM (r=0.9048). A lower correlation or no correlation was found for dc/DermaLab (r=0.8469; P=0.023) and dc/Skicon 200 (r=0.9000; P=0.083).Conclusions: For each of the five instruments, the electrical field of measurement can be assumed to cover the following depths: CM 820, between 30 and 45 μm; CM 825, around or less than 15 μm; Skicon 200, less than 15 μm; Nova DPM, between 45 and 60 μm; DermaLab, around or less than 15 nm.

Studies on Skin Elasticity, Viscoelasticity and Hydration State of Stratum Corneum after Water Immersion with Alkaline Salts

Studies on Skin Elasticity, Viscoelasticity and Hydration State of Stratum Corneum after Water Immersion with Alkaline Salts

Individual and instrumental variations in irritant patch-test reactions-clinical evaluation and quantification by bioengineering methods

A major purpose of irritant patch testing is to differentiate between normal, delicate and less sensitive skin. To assess the usefulness of irritant patch testing, knowledge of variation in responses to identical patch tests is essential. In the present study inter- and intra-individual variation in irritant patch test reactions due to sodium lauryl sulphate and nonanoic acid is given when evaluated by traditional visual scoring as well as different non-invasive methods, i.e. measurement of transepidermal water loss, the hydration state of stratum corneum by electrical conductance, cutaneous blood flow by laser Doppler flowmetry, and measurement of skin thickness by 20-MHz ultrasound A-scan. The intra-individual 'site-to-site' variation was considerably less than the inter-individual variation, which is essential to differentiate between persons with delicate and less sensitive skin. Methods used were relevant for this purpose except for the measurement of electrical conductance.