A new ex vivo human skin model for the topographic and biological analysis of cosmetic formulas

• DOI: 10.1111/ics.13027
• Publication Date: 2024-11-13T11:16:09Z
• Authors: Laurent Peno‐Mazz...; Olivier Jeanneton; Stéphanie Almeida...; Giuseppe Percoco; Gallic Beauchef; Carine Nizard; Karl Pays
• Keywords: 03 medical and health sciences; 0302 clinical medicine

AbstractObjectiveExisting methods to evaluate skin care products suffer limitations. This is the case for ex vivo skin explants, a first‐choice 3D model. While essential to analyse mid‐ to long‐term biological effects, this classical model hinders assessing microrelief variations. To circumvent these limitations, we developed an ex vivo PERFused EXplant setup (Perfex) that maintains the outer skin surface in the open air, closely mirroring physiological conditions.MethodsA custom‐designed reservoir enables perfusing the dermal side of explants with buffered, temperature‐controlled medium, while the epidermis is subjected to “normal” conditions. Skin tension and characteristics of the stratum corneum, microrelief, histology and immunohistology (collagen types I and III, elastin and fibrillin‐1) were analysed and compared to those of explants maintained under conventional conditions or in vivo skin. The effects of skin care formulas intended to induce short‐ and/or mid‐ to long‐term effects were also assessed.ResultsSkin explants maintained with the Perfex setup exhibit characteristics (firmness, elasticity, hydration and barrier function) closer to those of in vivo skin than with conventional conditions. Moreover, Perfex‐maintained explants present no alteration in histology after 7 days and slight variation in the expression of key protein markers. Microrelief characteristics also remain mostly stable over 7 days. Formula applications corroborate that skin tensor‐containing products primarily induce short‐term changes in the microrelief, while those with biologically active ingredients mainly lead to mid‐ to long‐term effects on the histology and expression of molecular markers. Furthermore, maintaining skin explants with a physiologically relevant skin surface enabled analysing the relationship between microrelief and key markers, showing that fibrillin‐1 is the protein most correlated with microrelief characteristics.ConclusionsThe Perfex setup allows for similar preservation of skin explant histology and key protein expression as the conventional system, yet it maintains a skin surface close to that of in vivo skin. Therefore, it is valuable to analyse both the short‐ and mid‐ to long‐term impacts of skin care formulas and better comprehend their effects. The Perfex system also offers a new tool for investigating fundamental questions, such as the link that can exist between dermal proteins and skin surface properties.