Preclinical studies frequently lack predictive value for human conditions. Human cell-based disease models that reflect patient heterogeneity may reduce the high failure rates of preclinical research. Herein, we investigated the impact of primary cell age and body region on skin homeostasis, epidermal differentiation, and drug uptake. Fibroblasts derived from the breast skin of female 20- to 30-year-olds or 60- to 70-year-olds and fibroblasts from juvenile foreskin (<10 years old) were compared in cell monolayers and in reconstructed human skin (RHS). RHS containing aged fibroblasts differed from its juvenile and adult counterparts, especially in terms of the dermal extracellular matrix composition and interleukin-6 levels. The site from which the fibroblasts were derived appeared to alter fibroblast-keratinocyte crosstalk by affecting, among other things, the levels of granulocyte-macrophage colony-stimulating factor. Consequently, the epidermal expression of filaggrin and e-cadherin was increased in RHS containing breast skin fibroblasts, as were lipid levels in the stratum corneum. In conclusion, the region of the body from which fibroblasts are derived appears to affect the epidermal differentiation of RHS, while the age of the fibroblast donors determines the expression of proteins involved in wound healing. Emulating patient heterogeneity in preclinical studies might improve the treatment of age-related skin conditions.

• MeSH
• Cell Differentiation MeSH
• Adult MeSH
• Epidermal Cells cytology   metabolism   MeSH
• Fibroblasts metabolism   pathology   MeSH
• Filaggrin Proteins MeSH
• Wound Healing MeSH
• Homeostasis MeSH
• Cells, Cultured MeSH
• Skin anatomy & histology   cytology   MeSH
• Middle Aged MeSH
• Humans MeSH
• Young Adult MeSH
• Foreskin cytology   MeSH
• Primary Cell Culture MeSH
• Breast anatomy & histology   cytology   MeSH
• Aged MeSH
• Cellular Senescence physiology   MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Young Adult MeSH
• Male MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Comparative Study MeSH

Aging depicts one of the major challenges in pharmacology owing to its complexity and heterogeneity. Thereby, advanced glycated end-products modify extracellular matrix proteins, but the consequences on the skin barrier function remain heavily understudied. Herein, we utilized transmission electron microscopy for the ultrastructural analysis of ribose-induced glycated reconstructed human skin (RHS). Molecular and functional insights substantiated the ultrastructural characterization and proved the relevance of glycated RHS beyond skin aging. In particular, electron microscopy mapped the accumulation and altered spatial orientation of fibrils and filaments in the dermal compartment of glycated RHS. Moreover, the epidermal basement membrane appeared thicker in glycated than in non-glycated RHS, but electron microscopy identified longitudinal clusters of the finest collagen fibrils instead of real thickening. The stratum granulosum contained more cell layers, the morphology of keratohyalin granules decidedly differed, and the stratum corneum lipid order increased in ribose-induced glycated RHS, while the skin barrier function was almost not affected. In conclusion, dermal advanced glycated end-products markedly changed the epidermal morphology, underlining the importance of matrix⁻cell interactions. The phenotype of ribose-induced glycated RHS emulated aged skin in the dermis, while the two to three times increased thickness of the stratum granulosum resembled poorer cornification.

• Keywords
• advanced glycated end products, aging, diabetes, electron microscopy, nanomedicine, reconstructed human skin, ribose, skin absorption,
• MeSH
• Basement Membrane drug effects   ultrastructure   MeSH
• Cell Differentiation drug effects   MeSH
• Epidermis drug effects   ultrastructure   MeSH
• Fibroblasts drug effects   ultrastructure   MeSH
• Keratinocytes drug effects   ultrastructure   MeSH
• Skin drug effects   ultrastructure   MeSH
• Humans MeSH
• Glycation End Products, Advanced metabolism   MeSH
• Ribose pharmacology   MeSH
• Dermis drug effects   ultrastructure   MeSH
• Skin Aging drug effects   MeSH
• Microscopy, Electron, Transmission MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Glycation End Products, Advanced MeSH
• Ribose MeSH