Thrombin induces production of growth factors from aortic smooth muscle cells.

Background. Myointimal hyperplasia is a common complication of arterial recontructive surgery. The serine protease thrombin has a major role in vessel wall healing and eventual myointimal hyperplasia formation. The aim of this study was to determine the effect of thrombin on the production of PDGF AA and bFGF by arterial smooth muscle cells. Materials and methods. Bovine smooth muscle cells were stimulated with thrombin in a serum-free culture. The release of PDGF AA and bFGF was assessed by ELISA. The effect of thrombin on the proliferation of confluent monolayers of bovine smooth muscle cells was determined by tritiated thymidine uptake. Results. Smooth muscle cells stimulated with thrombin released more PDGF AA (P < 0.001) and bFGF (P < 0.001) than the control. Addition of anti-PDGF AA and anti-bFGF antibodies to the medium of smooth muscle cell cultures neutralized the mitogenic effect of thrombin (P < 0.001). Conclusions. The findings of our study suggest that thrombin may lead to myointimal hyperplasia formation through induction of PDGF and bFGF production by smooth muscle cells.