Platelet-derived growth factor promotes smooth muscle migration and intimal thickening in a rat model of balloon angioplasty.

Platelet-derived growth factor (PDGF) is a mitogen and che- moattractant for vascular smooth muscle cells (SMC) in vitro, but its activities in vivo remain largely undefined. We infused recombinant PDGF-BB (0.01-0.30 mg/kg per d i.v.) into rats subjected to carotid injury. PDGF-BB produced a small in- crease (twoto threefold) in medial SMC proliferation. More importantly, PDGF-BB greatly increased (20-fold) the intimal thickening and the migration of SMC from the media to the intima during the first 7 d after injury. These data provide sup- port for the hypothesis that PDGF, and perhaps other platelet factors, might play an important role in the movement of mesen- chymal cells into zones of injury undergoing repair. (