Nature versus nurture: does human skin maintain its stratum corneum lipid properties in vitro?

Abstract

Human skin equivalents (HSEs) mimic human skin closely, but show differences in their stratum corneum (SC) lipid properties. The aim of this study was to determine whether isolation of primary cells, which is needed to generate HSEs, influence the SC lipid properties of HSEs. For this purpose, we expanded explants of intact full thickness human skin and isolated epidermal sheets in vitro. We investigated whether their outgrowths maintain barrier properties of human skin. The results reveal that the outgrowths and human skin have a similar morphology and expression of several differentiation markers, except for an increased expression of keratin 16 and involucrin. The outgrowths show a decreased SC fatty acid content compared with human skin. Additionally, SC lipids of the outgrowths have a predominantly hexagonal packing, whereas human skin has the dense orthorhombic packing. Furthermore, the outgrowths have lipid lamellae with a slightly reduced periodicity compared with human skin. These results demonstrate that the outgrowths do not maintain all properties observed in human skin, indicating that changes in properties of HSEs are not caused by isolation of primary cells, but by culture conditions.

Improved epidermal barrier formation in human skin models by chitosan modulated dermal matrices

“…Since the repeat distance of the LPP in NHS is approximately 13 nm [44], this indicates that the lamellar organization of CC-FTMs resembles that of NHS to a higher extent but still not completely. Moreover, the additional unknown lamellar phase in FTMs, possibly explained by phase separated CERs, is not present in CC-FTMs and NHS [8].…”

Exploring the potentials of nurture: 2nd and 3rd generation explant human skin equivalents

“…Therefore the orthorhombic packing cannot be reproduced in vitro under conditions described in this study. Only a hexagonal lateral packing was observed in the 2 nd and 3 rd generation outgrowths, similar to other epidermal and full thickness HSEs [12,[25][26][27]. The abundant formation of a hexagonal packing in culture may be explained by: a reduction in SC FFAs levels and in their chain lengths or by an increase in the relative levels of MUFAs [28].…”

“…Our previous studies showed that the 1 st generation Ex-HSEs do not fully maintain SC lipid properties as in native human skin [12]. Therefore, we investigated whether passaging to the 2 nd and 3 rd generation results in SC lipid properties similar to the 1 st generation.…”

“…To analyze the FFA composition in more detail, we examined the chain length distribution and saturation of the FFAs using LC-MS as this was not done in our previous study focusing on the 1 st generation of Ex-HSE [12]. The FFA chain lengths with C16-C18 were excluded from the analysis to avoid false positive results from sebaceous lipids and subcutaneous fat from native human skin.…”

Skin Tissue-Engineering Constructs and Stem Cells Application for the Skin Equivalents Creation (Review)

“…with Graftskin with compression was significantly more effective in achieving complete wound closure at 8 weeks (AST2000) CellSystems Biotechnologie, GmbH (Germany) It is a full-layer human skin model consisting of fibroblasts as a basal skin layer and keratinocytes as the epidermis Leiden epidermal skin model for the assessment of skin condition after its exposure to aggressive chemical agents Thakoersing, Bouwstra et al [161,162], and EI Ghalbzouri [163] (Netherlands) It is a full-layer human skin model consisting of fibroblasts in 3D collagen matrix as a basal skin layer and keratinocytes as the epidermis…”