Distribution of Domains Formed by Lateral Packing of Intercellular Lipid in the Stratum Corneum

Abstract

Intercellular lipids fill the interstices of corneocytes and serve a barrier function. The amount of transdermal water evaporation varies depending on the packing structure of intercellular lipids, as this structure is important for maintaining barrier efficacy. This packing structure consists of a mixture of crystals (orthorhombic and hexagonal) and liquid crystals (fluid phase), and the proportion of these phases is thought to affect barrier function. However, there have been no methods to visualize the actual distribution of the domains formed by packing structure in intercellular lipids. In this study, the planar distribution of intercellular lipid structures was determined using focal plane array (FPA)-based Fourier transform (FT) IR imaging analysis of stratum corneum cell units obtained by grid stripping. The lipid composition of ceramides was revealed by electrospray ionization tandem mass spectrometry (ESI-MS/MS)-based shotgun lipidomics. The distribution of domains formed by packing structures and the lipid composition of ceramides was compared in skin with high-or low-transepidermal water loss (TEWL). The orthorhombic proportion was lower in high-TEWL skin than in low-TEWL skin. ESI-MS/MS-based shotgun lipidomics analysis showed that the alpha-hydroxyceramide content in the low-and high-TEWL groups differed regarding the distribution of fatty acid chain lengths. The evaluation of stratum corneum cell units using FPA-based FTIR imaging is an innovative technology that can visualize the distribution of domains formed by intercellular lipid-packing structures. Increased proportions of alpha-hydroxyceramide subclasses such as alpha-hydroxy-sphingosine ceramide and alpha-hydroxy-phytosphingosine ceramide were associated with a reduced proportion of the orthorhombic packing structure domain.

Efficacy of Topical Application of a Skin Moisturizer Containing Pseudo-Ceramide and a Eucalyptus Leaf Extract on Atopic Dermatitis: A Review

“…In addition to the variation in subclasses, their total chain length (sphingoid base + acyl chain) varies substantially between around 32 and 72 carbon atoms. The variation in the length of the sphingoid bases is much less than the variation in the acyl chain length [ 48 , 49 , 50 ]. The ceramides’ EO subclasses are defined as all subclasses with a very long ω-hydroxy acyl chain ester linked to a fatty acid chain with 18 carbon atoms, the majority of which is a linoleate [ 51 ].…”

Effects and Mode of Action of Oleic Acid and Tween 80 on Skin Permeation of Disulfiram

“…[8][9][10][11] The peculiar structure of this intercellular lipid changes with a phase transition, identified by temperature scanning, 12) and its relationship with the barrier function of the SC has been clarified. [13][14][15][16][17][18] Due to the barrier function of the SC resulting from these regular arrangements, it is difficult to deliver enough drug into the body for treatment. 19) Therefore, it is difficult to develop transdermal formulations of a wide variety of drugs, and the drugs developed thus far meet the following conditions.…”