Objectives Fibrosis 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.
Methods Skin 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.
Results Skin 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.
Conclusion Our 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.
- systemic sclerosis
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Handling editor Josef S Smolen
A-EM, C-WC, FG-B and JHWD contributed equally.
Contributors A-EM, C-WC, FG-B and JHWD designed the study. A-EM, C-WC, LK, A-HG, Y-NL, TT-M., XX, CTM were involved in acquisition of data. A-EM, C-WC, A-HG, LK, AJ, GS, FG-B and JHWD were involved in interpretation of data. A-EM and JHWD were involved in manuscript preparation. THvK, JH and FG-B provided essential materials.
Funding Grants DI 1537/9-1 and DI 1537/9-2, DI 1537/11-1, DI 1537/12-1, DI 1537/13-1, DI 1537/14-1 and RA 2506/3-1 of the German Research Foundation, SFB CRC1181 (project C01) and SFB TR221/ project number 324392634 (B04) of the German Research Foundation; grants J40 and A64 of the IZKF in Erlangen; grants 2014_A47 and 2014_A184 of the Else-Kröner-Fresenius-Foundation; grant 14-12-17-1-Bergmann of the ELAN-Foundation Erlangen and a Career Support Award of Medicine of the Ernst Jung Foundation. AJ is a member of the SKINTEGRITY consortium at University Medicine Zürich/Hochschulmedizin Zürich.
Competing interests JHWD has consultancy relationships and/or has received research funding from Actelion, BMS, Celgene, Bayer Pharma, Boehringer Ingelheim, JB Therapeutics, Sanofi-Aventis, Novartis, UCB, GSK, Array Biopharma and Active Biotech in the area of potential treatments of SSc and is stock owner of 4D Science GmbH.
Patient consent for publication Not required.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available on reasonable request.
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