Characterization of human skin equivalents developed at body's core and surface temperatures

Abstract

Human skin equivalents (HSEs) are in vitro developed three‐dimensional models resembling native human skin (NHS) to a high extent. However, the epidermal lipid biosynthesis, barrier lipid composition, and organization are altered, leading to an elevated diffusion rate of therapeutic molecules. The altered lipid barrier formation in HSEs may be induced by standardized culture conditions, including a culture temperature of 37°C, which is dissimilar to skin surface temperature. Therefore, we aim to determine the influence of culture temperature during the generation of full thickness models (FTMs) on epidermal morphogenesis and lipid barrier formation. For this purpose, FTMs were developed at conventional core temperature (37°C) or lower temperatures (35°C and 33°C) and evaluated over a time period of 4 weeks. The stratum corneum (SC) lipid composition was analysed using advanced liquid chromatography coupled to mass spectrometry analysis. Our results show that SC layers accumulated at a similar rate irrespective of culture temperature. At reduced culture temperature, an increased epidermal thickness, a disorganization of the lower epidermal cell layers, a delayed early differentiation, and an enlargement of granular cells were detected. Interestingly, melanogenesis was reduced at lower temperature. The ceramide subclass profile, chain length distribution, and level of unsaturated ceramides were similar in FTMs generated at 37°C and 35°C but changed when generated at 33°C, reducing the resemblance to NHS. Herein, we report that culture temperature affects epidermal morphogenesis substantially and to a lesser extent the lipid barrier formation, highlighting the importance of optimized external parameters during reconstruction of skin.

TatS: a novel in vitro tattooed human skin model for improved pigment toxicology research

“…The overall morphology and the abundance of development and homeostasis markers remained unchanged upon incorporation of pigments and are comparable to normal full thickness skin models that are already used in toxicology testing (Bataillon et al 2019 ; Hayden et al 2015 ). The presence of collagen IV as a marker of basement membrane formation and the epidermal thickness are similar to those of other human full thickness skin models made with rat tail tendon collagen cultured under the same conditions (Mieremet et al 2019 ). The pigmented layer with a maximum starting depth of around 800 µm beneath the basement membrane is in range of the in vivo situation, were most pigments lay in a depth of 200–1300 µm (Ross et al 2001 ).…”

3D-Organotypic Cultures to Unravel Molecular and Cellular Abnormalities in Atopic Dermatitis and Ichthyosis Vulgaris

“…However, the expression of most differentiation and tight junction markers as well as genes related to lipid metabolism and AMPs was similar in both culture conditions, with the exception of FLG and two osmolyte regulators [62]. Similarly, culture temperature (33 °C versus 37 °C) can moderately affect the expression of epidermal differentiation markers and the composition of SC ceramides [63]. Thus, in the future, both the humidity and temperature of 3D cultures should be more carefully considered, especially for studying epidermal barrier function.…”

Contribution of Palmitic Acid to Epidermal Morphogenesis and Lipid Barrier Formation in Human Skin Equivalents

“…Therefore, these are widely applied in preclinical screenings and for research purposes to increase understanding of skin biology and epidermal barrier formation in healthy and diseased phenotypes [1,2,3,4,5,6]. HSEs mimic NHS in morphologic appearance, including the presence of distinguishable epidermal layers and formation of the SC [7,8,9]. Characterization of the barrier formation in HSEs revealed similarities as well as differences compared to the barrier formation of NHS.…”