389 Pirfenidone inhibits RDEB fibrosis and scarring

Abstract

Patients with recessive dystrophic epidermolysis bullosa (RDEB) develop multiple skin wounds that heal with extensive scarring, contractures and mitten deformities. RDEB patients display increased pro-fibrotic TGF-β signaling, a distinct pro-fibrotic gene expression profile and elevated inflammation genes. So far, no specific pharmacological treatment is available for RDEB fibrosis. Among promising anti-fibrotic molecules, pirfenidone (PFD) has shown anti-fibrotic and anti-inflammatory activity in animal and cell models, and it is already being used clinically for the treatment of idiopathic pulmonary fibrosis. In this study, we evaluated the feasibility of using PFD to inhibit RDEB fibrosis using fibroblasts from RDEB patients and a RDEB mouse model. RDEB fibroblasts treated with PFD demonstrated reduced expression of multiple fibrosis markers [collagen I, connective tissue growth factor (CTGF), alpha smooth muscle actin (α-SMA), periostin, and tenascin C] by immunoblot analysis. By RT-PCR, PFD also reduced mRNA levels for fibrosis genes [tenascin-C, CTGF, periostin, TGF-β2, and α-SMA] as well as IL-6, an inflammation gene known to stimulate fibrosis. In addition, PFD reduced the levels of pro-fibrogenic TGF-β in the media of RDEB fibroblasts as assessed by ELISA. Furthermore, PFD also reversed the characteristic RDEB cellular phenotype of collagen lattice hypercontractability. Lastly, using a RDEB mouse model featuring nail dystrophy and mitten deformities, PFD administered once daily subcutaneously for 4 weeks attenuated the onset of RDEB-associated fibrosis including mitten deformities and nail loss. It reduced in the skin of RDEB mice, their intrinsically elevated fibrosis markers [periostin, α-SMA, fibronectin, collagen 1 and tenascin C] and pro-fibrogenic TGF-β and its downstream signaling [phospho-Smad2/3]. PFD also significantly reduced the number of cd11b-positive inflammatory cells in RDEB mice. These data demonstrate that PFD may be a non-invasive, safe and novel therapy for reducing RDEB fibrosis and scarring and improving the quality of life of RDEB patients.