Endothelium-derived vasoactive factors and their role in the coronary circulation.
The endothelium-due to its strategic anatomic position between the circulating blood and vascular smooth muscle-plays an important functional role in the coronary circulation. Endothelial cells release factors interfering with coagulation, platelet function, vascular tone, and growth. Endothelium-derived nitric oxide (NO) is the endogenous nitrovasodilator that is a potent inhibitor of platelet function and vasodilator. Together with prostacyclin, NO plays an important protective role in preventing platelet adhesion, aggregation, and coronary vasospasm. Endothelial cells also are a source of contracting factors such as endothelin-1, thromboxane A(2), and endoperoxides. Cardiovascular risk factors (hyperlipidemia, hypertension, and diabetes) inhibit the formation of endothelium-derived relaxing factors and promote that of contracting factors. In coronary arteries with advanced atherosclerosis, endothelial function is severely impaired. The reduced release of endothelium-derived NO is associated with an increased platelet-vessel-wall interaction and, in turn, platelet activation and vasospasm, both known events in coronary artery disease.
Department of Medicine, Division of Cardiology, and Department of Research, Laboratory of Vascular Research, University Hospital, CH-4031 Basel, Switzerland.
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Lüscher
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Richard
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