Two Ceramide Subfractions Detectable in Cer(AS) Position by HPTLC in Skin Surface Lipids of Non-Lesional Skin of Atopic Eczema

Abstract

The non-involved skin of atopic eczema (NEAE) is characterized by severe dryness and an impaired barrier function of the stratum corneum as indicated by an increased transepidermal water loss. Previous studies have demonstrated that this barrier impairment coincides with marked alterations in the amount and composition of stratum corneum ceramides. The aim of this study was to identify specific alterations in NEAE that may be used in the diagnosis of the atopic eczema. Using a classical procedure for high performance thin layer chromatography we could confirm earlier results: apart from Cer(EOH), which contains omega-hydroxy fatty acid (O) ester-linked to linoleic acid (E) and amide-linked to 6-hydroxy-4-sphingenine (H), the quantities of all ceramide fractions were significantly decreased. Furthermore, Cer(EOH)/Certotal was significantly increased, whereas the percentage of Cer(EOS), which contains sphingosine (S), and Cer(NP), which contains non-hydroxy fatty acid (N) amide-linked to phytosphingosine (P), were significantly decreased. Using a modified procedure for high performance thin layer chromatography we could demonstrate the formation of a double peak in the position of Cer(AS), which contains alpha-hydroxy fatty acid (A), in lipids of NEAE. The subfractions of the double peak comprised 15% and 12% of Certotal. MALDITOF mass spectrometry suggested that the double peak was formed by a homologous series of mono-hydroxylated and mono-unsaturated ceramides of different chain length, e.g., Cer(AS) subfractions containing either (C16,18) or (C22,24,26) alpha-hydroxy fatty acids. In contrast, in normal skin a single peak in Cer(AS) position, which comprised 22% of Certotal, was mainly formed by the long chain subfraction. In some cases this single peak displayed a small shoulder at its right flank, but never showed a clear peak separation when developed with NEAE samples. Furthermore, even in senile xerosis, or in either non-involved skin of psoriasis or seborrhoic eczema, only a single peak occurred in Cer(AS) position. Accordingly, the double peak might be specific for NEAE and turn out to be a marker for atopic eczema.

Alteration of the 4-sphingenine scaffolds of ceramides in keratinocyte-specific Arnt-deficient mice affects skin barrier function

“…Keratinocyte-specific (K5-Cre) disruption of Hif1α led to no overt phenotype (S. Tomita et al, unpublished observations), suggesting that the HIF1α/ARNT heterodimer is not responsible for the phenotype observed in this study. Although SIM1 and SIM2 are other candidates that can form heterodimers with ARNT (46) and can possibly activate the desaturase gene in the epidermis (47), they analysis indicated that Cer(EOS) and Cer(NP) levels were significantly diminished in these skin diseases (40). It would be of interest to compare the detailed structures of lamellae of these patients and of Arnt-null mice.…”

Increase in short-chain ceramides correlates with an altered lipid organization and decreased barrier function in atopic eczema patients

“…Several studies have reported signifi cant changes in CER subclasses in nonlesional SC of AE patients: reduced CER [NP], increased CER [AS], and reduced long chain CERs [EOH] and [EOS] ( 12,23,(34)(35)(36). Some of these changes could be correlated with changes in skin barrier function.…”

Impaired Epidermal Permeability Barrier in Mice Lacking Elovl1, the Gene Responsible for Very-Long-Chain Fatty Acid Production

“…Indeed, a deficiency in the synthesis of ULCFA-containing Cers results in the severe cutaneous disorder ichthyosis in both mice and humans (5)(6)(7)(8)(9)(10)(11). Furthermore, decreased levels of Cers and changes in Cer subclasses have been observed in the epidermis of persons with atopic dermatitis or psoriasis (12)(13)(14)(15)(16). Recently, shifts of Cers toward shorter chain lengths have also been reported in patients with atopic eczema (17).…”