Based on our clinical observations on pregnant woman skin, we hypothesized that stretched skin during pregnancy may share some inflammatory characteristics with psoriatic lesions. Indeed, there may be a direct relationship between mechanical tension and inflammation and we further suggested that this may contribute to the development of striae gravidarum during pregnancy. We developed in vitro models of stretched skin in order to better understand the inflammatory conditions and pathways involved in stretch marks formation. Keratinocytes or fibroblasts have been submitted to a uniaxial mechanical stretching using a device applying a cyclic tension on flexible-bottomed culture. The expression of inflammatory markers (TNFα, IL6, IL8, MMP1) increased at the gene and protein level in response to mechanical tension. Skin explants have been maintained under mechanical stress, between jaws, at constant force for up to 10 days. The stretching induced an increase in IL6, IL8 and MMP1 levels, confirming the link between skin mechanical tension and inflammatory pathways. Immuno-histology revealed alteration and disorganization of collagen and elastic fibers, reproducing the histological features of SG. Application of an SG prevention cream showed decreased levels of inflammatory markers and globally preserved dermal matrix organization; suggesting an efficient preventive effect on SG formation. Using in vitro models of stretched skin we confirmed the relationship between mechanical tension and inflammation, which may explain striae gravidarum development during pregnancy. This suggests that these in vitro and ex vivo models may be relevant and valuable tools 1) to demonstrate the biological activity of a SG prevention cream containing a specific composition of active ingredients and 2) to predict clinical efficacy. Further clinical study indeed confirmed that this product could prevent stretch mark formation.

ESDR368 - Stretch induces inflammation and contributes to striae gravidarum formation: in vitro models

50th Annual Meeting of the European Society for Dermatological Research. VIRTUAL MEETING