Nicotine induces platelet-derived growth factor release and cytoskeletal alteration in aortic smooth muscle cells

Background, Cigarette smoking is implicated in atherosclerotic plaque formation, but the role of nicotine in this process is not completely understood. The release of platelet-derived growth factor (PDGF) by the bovine aortic smooth muscle cell (SMC) after nicotine administration at a concentration similar to that ingested by active and passive smokers and the role of PDGF in SMC cytoskeleton modification were studied. Methods. SMC, harvested with enzymatic digestion from calf aorta, were stimulated in a serum-free medium for 72 hours with (-)-nicotine (from 6 x 10(4) mol/L to 6 x 10(8) mol/L). The release of PDGF was assessed by inhibition antibody-binding assay and confirmed by Western blotting. Mitogenic activity of nicotine on SMCs was also determined. The SMC cytoskeleton was studied with specific antibodies anti-alpha-actin fibers, anti-vimentin, and anti-beta-tubulin, and the modification induced by PDGF was assessed by blocking PDGF activity with specific antibodies. Results. The greatest PDGF release (1.24 +/- 0.14 ng/10(4) cells vs control 0.43 +/- 0.07 ng/10(4) cells) was noted at a (-)-nicotine concentration of 6 x 10(7) mol/L (P < .001). The addition of monoclonal antibody anti-PDGF decreased the tritiated thymidine uptake of SMCs exposed to (-)-nicotine compared with the control (29% vs 5% - P < .001). SMCs exposed to (-)-nicotine concentration of 6 x 10(7) mol/L and 6 x 10(8) mol/L had a significant alteration in the expression of alpha-actin fibers, vimentin, and beta-tubulin compared with central. The administration of antibody anti-PDGF in the culture medium reversed cytoskeletal alteration. Conclusions. Nicotine enhanced the release of platelet-derived growth, which in turn caused an alteration in cytoskeletal organization.