Role of Ceramide in the Barrier Function of the Stratum Corneum, Implications for the Pathogenesis of Atopic Dermatitis

Abstract

Clinical Characteristics as a Recurrent Dermatits The skin of patients with atopic dermatitis (AD) is mainly characterized by a clinically normal appearance but which exhibits a high susceptibility to irritants and allergens, dry skin and deficient innate immunity. Thus, as shown in Figure 1, an increased transepidermal water loss (TEWL) and decreased water content, even in the clinically normal skin of patients with AD suggest a marked down-regulation of both the barrier and the water holding functions. AD skin also shows a high frequency of S. aureus colonization even in the nonlesional skin, compared with no colonization in healthy control (HC) skin [1-4]. Abnormality in Cutaneous Permeability Barrier Function There is a general consensus that disruption of the barrier function of the stratum corneum (SC) is an essential etiologic factor for skin inflammation in patients with AD. Thus, AD could be considered as a barrier disease in which antigens and irritants that permeate the skin trigger and worsen the dermatitis. Since TEWL, which is frequently evaluated as an indication of barrier function, is not necessarily a precise reflection of cutaneous permeability, we determined whether chemical penetration is really enhanced or not in the nonlesional skin of AD patients compared with HC skin [5]. To evaluate in vivo cutaneous permeability, we used photoacoustic spectrometry by which chemical concentrations present through the layers of the SC can be measured using the intensity of photoacoustic signals derived from the chopped expansion of air due to chemical heat released from chemical molecules

A Randomized, Double-Blind, Placebo-Controlled Trial Assessing the Oral Administration of a Heat-Treated <b><i>Lactobacillus paracasei </i></b>Supplement in Infants with Atopic Dermatitis Receiving Topical Corticosteroid Therapy

“…The TEWL values in the unaffected skin at baseline were generally higher than those previously reported in Chinese infants [20] as well as other countries and ethnicity [21, 22]. This was particularly observed in the patients assigned to the GM080 group, supporting that the barrier may be compromised even in skin appearing clinically normal in AD patients [23]. The slight decrease in TEWL from the baseline value in all four of the affected anatomical locations pointed in the direction of an improvement in barrier function.…”

Sweat lipid mediator profiling: a noninvasive approach for cutaneous research

“…The increases in short-chain [NS] ceramides appear to be at odds with the generally reported decrease in total skin ceramides with AD (30). However, ceramides as a class are complex molecules, consisting of 12 reported species and present in different proportions in the skin, as described in supplemental Fig.…”

“…As we have reported increases in C32-C42 [NS] ceramides and C36 and C42 [NdS] ceramides in the sweat of subjects with AD, it would appear that our findings are consistent with the reported increases in CerS4 activity in subjects with AD. It remains unclear why CerS4, in particular, is increased in subjects with AD, whereas no reports exist of other ceramide synthase expression levels being affected by AD (30). One possibility is that increased short-chain [NS] ceramide levels would induce increased keratinocyte differentiation as a compensatory mechanism to repair a damaged epidermal barrier, but further research would be necessary to verify this or other explanations for the differential regulation of ceramide synthases in AD.…”

Microplasma Drug Delivery

“…Ceramides form a multilayer lamellar structure with other lipids. Ceramides also act as a water modulator and their decrease also decreases the water-holding capacity [34]. The majority of ceramides of the stratum corneum has an even number of carbons and the most abundant has 44 and 46 carbons.…”