PLATELET-DERIVED GROWTH-FACTOR IS RELEASED INTO THE CORONARY CIRCULATION AFTER CORONARY SPASM

Background: Platelet-derived growth factor (PDGF) is a potent mitogen for vascular smooth muscle cells and is implicated in the vascular res ponse to injury and the pathogenesis of atherosclerosis. It is also a potent vasoconstrictor. Methods: To examine whether acute myocardial i schemia increases the level of PDGF in the coronary circulation, we me asured plasma levels of PDGF in the coronary sinus and the aortic root simultaneously in 14 patients with coronary spastic angina. These mea surements were performed before and after the left coronary artery spa sm induced by intracoronary injection of acetylcholine, and measuremen ts were also taken in 15 patients with stable exertional angina before and after acute myocardial ischemia induced by rapid atrial pacing. E leven patients with chest pain but normal coronary arteries and no cor onary spasm served as controls. Results: Plasma PDGF levels increased significantly (P<0.01) from 274+/-28 pg/mL to 364+/-27 pg/mL only in c oronary sinus after anginal attacks in the patients with coronary spas tic angina. However, plasma PDGF levels in coronary sinus remained unc hanged after these attacks in the patients with stable exertional angi na (from 230+/-27 pg/ml to 247+/-28 pg/mL) and after intracoronary inj ection of aceytlcholine in the control subjects. Plasma PDGF levels in aortic root remained unchanged in all three patient groups. Conclusio ns: PDGF is released into the coronary circulation after coronary arte ry spasm, and this may exacerbate coronary artery spasm.