Hand eczema and stratum corneum ceramides.

BACKGROUND: Hand eczema (HE) is a multifactorial disease, comprising different aetiological conditions and different morphologies. There are two aetiologically distinct groups of HE recognised: exogenous, such as contact dermatitis (allergic and/or irritant HE) and endogenous, such as the classic hyperkeratotic HE. Differences in the skin barrier properties of these two conditions could theoretically be expected. AIM: To examine whether differences exist in the lipid profile and the susceptibility of the stratum corneum (SC) in patients with allergic/irritant HE and those with hyperkeratotic HE. METHODS: Using cyanoacrylate, SC samples were taken from 23 patients with allergic/irritant HE and 15 with hyperkeratotic HE for lipid analysis by high-performance thin-layer chromatography (HPTLC). Samples were also taken from adjacent, unaffected skin. Severity of HE was assessed by the Hand Eczema Severity Index (HECSI), and skin barrier susceptibility was assessed by measuring transepidermal water loss (TEWL) after a 24-hour patch test with sodium lauryl sulfate (SLS). RESULTS: No statistically significant difference was found between groups for the lipid analysis or for skin susceptibility to SLS. We found a significantly higher HECSI score for hyperkeratotic HE compared with irritant or allergic HE (P = 0.02). CONCLUSIONS: There appears to be no difference in skin barrier between allergic/irritant HE (exogenous eczema) and hyperkeratotic HE (endogenous eczema) with regard to SC lipids or susceptibility to SLS.

Human ß-defensin-2 as a marker for disease severity and skin barrier properties in atopic dermatitis.

BACKGROUND: Skin infections related to disrupted antimicrobial defence are a common problem in atopic dermatitis (AD). Altered levels of antimicrobial peptides, including human ß-defensin (hBD)-2, have been reported in AD skin, and a link to impaired barrier function has been suggested. OBJECTIVES: To study hBD-2 in relation to skin barrier function in patients with AD and controls, and to study hBD-2 in relation to disease severity. METHODS: Twenty-five patients with AD and 11 controls were enrolled. hBD-2 peptide concentration was determined in stratum corneum samples collected by a minimally invasive tape-stripping method. Disease severity was assessed by SCORing Atopic Dermatitis (SCORAD), and skin barrier function was evaluated by measurement of transepidermal water loss (TEWL) and skin pH. Patients with AD were characterized according to filaggrin mutations. RESULTS: hBD-2 concentrations in the stratum corneum were found to differ between lesional and nonlesional AD skin and controls, with the highest values in lesional skin (P < 0·001). SCORAD and TEWL were significantly increased in participants with measureable hBD-2 (P < 0·018 and P < 0·007, respectively). Significant correlations between hBD-2 in lesional skin, and TEWL and SCORAD were observed (R = 0·55 and R = 0·44, respectively). No correlations with skin pH were found. hBD-2 was not found to relate to filaggrin mutations. CONCLUSIONS: A significant correlation was found between hBD-2, disturbed skin barrier function and disease severity. The minimally invasive skin sample technique enables evaluation of the stratum corneum and its proteins over time and provides the possibility of relating these findings to treatment, infections and physiological variations.

Ceramide profile in hypohidrotic ectodermal dysplasia.

BACKGROUND: Hypohidrotic ectodermal dysplasia (HED) is a rare genetic disease. The clinical presentation includes lack of sweating ability, and an often widely spread dermatitis resembling atopic dermatitis (AD). In AD, the skin-barrier defect is partly ascribed to the altered lipid profile in the stratum corneum and partly to mutations of the filaggrin genes. To our knowledge, no data are available about the epidermal lipid profile of HED. AIM: To compare the ceramide profile for patients with HED and AD. METHODS: The ceramide profile and ceramide/cholesterol ratio were compared between patients with HED (n = 7) and patients with AD (n = 21), using cyanoacrylate to take biopsy samples from the stratum corneum. Lipids were extracted from the biopsies and analysed using high-performance thin-layer chromatography. RESULTS: The lipid profiles of HED and AD were similar in distribution, apart from ceramide 1, which was significantly higher in HED (P = 0.04). CONCLUSIONS: The increased ceramide 1 level found in HED compared with AD is known to play a role in the structure of the lipid bilayers. However, further studies are needed to identify the functional significance of these observations and thereby elucidate differences in the skin barrier between HED and AD.

Stratum corneum lipids, skin barrier function and filaggrin mutations in patients with atopic eczema.

BACKGROUND: Prior to the discovery of filaggrin (FLG) mutations, evidence for an impaired skin barrier in atopic dermatitis (AD) has been documented, and changes in ceramide profile, altered skin pH and increased trans-epidermal water loss (TEWL) in patients with AD have been reported. Until now, no studies have analysed stratum corneum (SC) lipids combined with skin barrier parameters in subjects of known FLG genotype. METHODS: A cohort of 49 German individuals genotyped for the most common FLG mutations (R501X, 2282del4) had SC samples taken for lipid analysis by high-performance thin layer chromatography. In addition, TEWL, erythema, skin hydration and pH were measured. In 27 of the 49 individuals, a 24-h irritation patch test with sodium lauryl sulphate was performed. For the analysis, both the AD group and the control group were stratified by FLG mutation status (FLGmut/FLGwt). RESULTS: In the FLGmut AD group, significantly lower levels of ceramide 4 and significantly higher levels of ceramide 7 were observed when compared to both healthy control groups. However, ceramide 7 levels also significantly differed between FLGwt AD and FLGwt controls, as did ceramide 1 levels. No significant differences were observed for ceramide 2, 3, 5 and 6. FLGmut individuals had significantly higher skin pH values than individuals not carrying FLG mutations. Patients with AD with FLG mutations had significantly higher erythema compared to patients with AD without FLG mutations. CONCLUSION: Our results confirm previous observations of altered ceramide levels in AD, which however appear to show no clear relationship with FLG mutations.

Ethnicity and stratum corneum ceramides.

BACKGROUND: The barrier function of the skin is dependent on an optimal composition of the stratum corneum lipids, exemplified by the altered lipid profile in patients with atopic eczema (AE). Differences in the global prevalence of AE point to the environment as an important factor in AE. Studies on filaggrin point to a genetic aspect in AE. The influence of environment and genes needs to be explored. OBJECTIVES: To investigate possible differences in stratum corneum lipids between different healthy ethnicities living in the same environment. METHODS: Healthy participants without any major skin diseases were enrolled in the study. Twenty-five participants of Asian origin (Asians), 18 of African origin (Africans) and 28 of Danish origin (white-skinned), all students at universities in the Copenhagen area of Denmark, had the ceramide profile of their stratum corneum examined using the cyanoacrylate method and analysed using high-performance thin layer chromatography. RESULTS: For the ceramide/cholesterol ratio we found statistically significant differences between groups, with Asians having the highest ratio (P < 0·001 as compared with both white-skinned individuals and Africans), white-skinned individuals having intermediate values, and Africans having the lowest values. No statistically significant differences were found between any of the ceramide subgroups. CONCLUSIONS: We found different ceramide/cholesterol ratios in comparable groups of different ethnicity, pointing to unknown genetic differences.

Validation of cyanoacrylate method for collection of stratum corneum in human skin for lipid analysis.

BACKGROUND AND OBJECTIVE: Lipids in the stratum corneum (SC) are of major importance for the skin barrier function. Many different methods have been used for the collection of SC for the analysis of SC lipids. The objective of the present study was to validate the cyanoacrylate method for the collection of SC in relation to lipid analysis. METHODS: The results of the lipid analysis (ceramide/cholesterol and ceramide profile) of SC samples obtained by the cyanoacrylate method were compared to the results of the lipid analysis of mechanically removed SC samples. The intra- and interindividual variations in lipid composition were assessed when using the cyanoacrylate method, and lipid compositions in cyanoacrylate samples and samples taken from different depths of SC were compared. RESULTS: No statistically significant differences were found between mean values of lipids from the mechanically removed total thickness of the SC and cyanoacrylate samples. With respect to the cyanoacrylate samples, the intraindividual variation was significantly smaller than the interindividual variation, and the results did not indicate a change in lipid profile related to the depth of SC. The results clearly indicate that the cyanoacrylate method used for obtaining SC for lipid analysis is a useful and valid method for the purpose.