Vascularised human skin equivalents as a novel in vitro model of skin fibrosis and platform for testing of antifibrotic drugs

Abstract

ObjectivesFibrosis is a complex pathophysiological process involving interplay between multiple cell types. Experimental modelling of fibrosis is essential for the understanding of its pathogenesis and for testing of putative antifibrotic drugs. However, most current models employ either phylogenetically distant species or rely on human cells cultured in an artificial environment. Here we evaluated the potential of vascularised in vitro human skin equivalents as a novel model of skin fibrosis and a platform for the evaluation of antifibrotic drugs.MethodsSkin equivalents were assembled on a three-dimensional extracellular matrix by sequential seeding of endothelial cells, fibroblasts and keratinocytes. Fibrotic transformation on exposure to transforming growth factor-β (TGFβ) and response to treatment with nintedanib as an established antifibrotic agent were evaluated by quantitative polymerase chain reaction (qPCR), capillary Western immunoassay, immunostaining and histology.ResultsSkin equivalents perfused at a physiological pressure formed a mature, polarised epidermis, a stratified dermis and a functional vessel system. Exposure of these models to TGFβ recapitulated key features of SSc skin with activation of TGFβ pathways, fibroblast to myofibroblast transition, increased release of collagen and excessive deposition of extracellular matrix. Treatment with the antifibrotic agent nintedanib ameliorated this fibrotic transformation.ConclusionOur data provide evidence that vascularised skin equivalents can replicate key features of fibrotic skin and may serve as a platform for evaluation of antifibrotic drugs in a pathophysiologically relevant human setting.

In search for the ideal anatomical composition of vascularised human skin equivalents for systemic sclerosis translational research: should we recruit the telocytes?

“…Overall, we are confident that this pioneer work1 will represent the necessary groundwork for further studies devoted to refining the 3D composition of vascularised human skin equivalent systems. This effort may increase even more their similarity to the microscopic anatomical structure of human skin and some interesting cues should be considered.…”

“…The recent paper by Matei et al 1 has raised our interest on the feasibility and reliability of vascularised human skin equivalents for fibrosis research. This is a novel in vitro model which may replicate key features of fibrotic skin and may become a valuable platform for preclinical testing of innovative therapeutic strategies for systemic sclerosis (SSc) and other cutaneous fibrosing conditions.…”

“…This is a novel in vitro model which may replicate key features of fibrotic skin and may become a valuable platform for preclinical testing of innovative therapeutic strategies for systemic sclerosis (SSc) and other cutaneous fibrosing conditions. In this informative study, an engineered human skin equivalent featuring a functional vascular system with physiological perfusion was established by sequential seeding of primary human endothelial cells, fibroblasts and keratinocytes on a three-dimensional (3D) extracellular matrix scaffold 1. Elegantly, the authors have shown that their 3D system may reproduce the main features of human skin relevant for the pathogenesis of skin fibrosis.…”

“…Elegantly, the authors have shown that their 3D system may reproduce the main features of human skin relevant for the pathogenesis of skin fibrosis. Indeed, the exposure of these vascularised human skin equivalents to profibrotic transforming growth factor-β (TGFβ) has induced the fibroblast-to-myofibroblast transition and abnormal deposition of extracellular matrix, thus closely mimicking the SSc skin microenvironment 1. Moreover, the induction of dermal fibrosis was efficiently prevented by nintedanib, a tyrosine kinase inhibitor with proven antifibrotic effects, which further demonstrated that this model might serve as a suitable test system for future targeted therapies.…”

“…Moreover, the induction of dermal fibrosis was efficiently prevented by nintedanib, a tyrosine kinase inhibitor with proven antifibrotic effects, which further demonstrated that this model might serve as a suitable test system for future targeted therapies. The authors have also clearly discussed how their innovative model may help in overcoming many limitations currently encountered by scientists engaged in SSc translational research when using classical two-dimensional cell culture systems and in vivo mouse models 1…”