Anti-fibrotic effects of pirfenidone on pulmonary arterial vascular smooth muscle cells

Abstract

Background: Pulmonary arterial hypertension (PAH) is devastating disease with no cure. Pulmonary arterial vascular smooth muscle cells (PASMCs) proliferation and migration, and overproduction collagen, are important pathological processes in pulmonary vascular remodeling. Pirfenidone, the first anti-fibrotic drug approved for the treatment of Idiopathic pulmonary fibrosis (IPF). We hypothesize that pirfenidone may inhibit collagen synthesis and cell proliferation of PASMCs induced by growth factors in pulmonary hypertension. Method: Effects of pirfenidone on human PASMCs proliferation, migration and collagen secretion were studied. Proliferation of PASMCs was monitored by newly synthesized DNA with BrdU. PASMCs migration assay was performed with Ibidi chamber method. Collagen secretion in the medium was measured by Sircol assay. Real time PCR was applied for quantifying the pro-inflammatory cytokines interleukin rnRNA expression. Results: Pirfenidone inhibited the PDGF induced proliferation of PASMCs in dose depended manner. Pirfenidone significantly decreased PDGF-induced PASMCs migration compare to vehicle treatment (p<0.01). PDGF stimulated collagen secretion in the medium was significantly attenuated by Pirfenidone in comparison with vehicle in dose depended manner from 6.90±0.19 ug/ml (vehicle) to 6.02±0.21 ug/ml (0.1 mg/ml), 5.78±0.32 ug/ml (0.3 mg/ml) and 4.85±0.44 ug/ml (1 mg/ml), all p<0.01 vs Vehicle. Furthermore, PDGF stimulated IL-1a, IL-1b and IL-6 mRNA increase were also inhibited by pirfenidone. Conclusion: Pirfenidone effectively inhibit PDGF-induced PASMCs proliferation, migration and collagen secretion. Further investigations in an animal model of PAH are warranted.