Pioglitazone Alleviates Cardiac Fibrosis and Inhibits Endothelial to Mesenchymal Transition Induced by Pressure Overload.

BACKGROUND/AIMS: Cardiac fibrosis, characterized by an unbalanced production and degradation of extracellular matrix components, is a common pathophysiology of multiple cardiovascular diseases. Recent studies suggested that endothelial to mesenchymal transition (EndMT) could be a source of activated fibroblasts and contribute to cardiac fibrosis. Here, the role of pioglitazone (PIO) in cardiac fibrosis and EndMT was elaborated.

METHODS

Male C57BL/6 mice were subjected to aortic banding (AB), which was used to construct a model of pressure overload-induced cardiac hypertrophy. PIO and GW9662 was given for 4 weeks to detect the effects of PIO on EndMT.

RESULTS

Our results showed PIO treatment attenuated cardiac hypertrophy, dysfunction and fibrosis response to pressure overload. Mechanistically, PIO suppressed the TGF-β/Smad signaling pathway activated by 4-week AB surgery. Moreover, PIO dramatically inhibited EndMT in vivo and in vitro stimulated by pressure overload or TGF-β. A selective antagonist of PPAR-γ, GW9662, neutralized the anti-fibrotic effect and abolished the inhibitory effect of EndMT during the treatment of PIO.

CONCLUSION

Our data implied that PIO exerts an alleviative effect on cardiac fibrosis via inhibition of the TGF-β/Smad signaling pathway and EndMT by activating PPAR-γ.