Platelet-derived growth factor is released into the coronary circulation after coronary spasm

Platelet-derived growth factor (PDGF) is a potent mitogen for vascular smooth muscle cells and is implicated in the vascular response to injury and the pathogenesis of atherosclerosis. It is also a potent vasoconstrictor.

To examine whether acute myocardial ischemia increases the level of PDGF in the coronary circulation, we measured plasma levels of PDGF in the coronary sinus and the aortic root simultaneously in 14 patients with coronary spastic angina. These measurements were performed before and after the left coronary artery spasm induced by intracoronary injection of acetylcholine, and measurements were also taken in 15 patients with stable exertional angina before and after acute myocardial ischemia induced by rapid atrial pacing. Eleven patients with chest pain but normal coronary arteries and no coronary spasm served as controls.

Plasma PDGF levels increased significantly (P < 0.01) from 274 +/- 28 pg/mL to 364 +/- 27 pg/mL only in coronary sinus after anginal attacks in the patients with coronary spastic angina. However, plasma PDGF levels in coronary sinus remained unchanged after these attacks in the patients with stable exertional angina (from 230 +/- 27 pg/ml to 247 +/- 28 pg/mL) and after intracoronary injection of acetylcholine in the control subjects. Plasma PDGF levels in aortic root remained unchanged in all three patient groups.

PDGF is released into the coronary circulation after coronary artery spasm, and this may exacerbate coronary artery spasm.