The endothelium in health and in cardiovascular disease.

Significant new findings in the last decade have demonstrated that the vascular endothelium is an important regulatory organ in maintaining cardiovascular homeostasis and that endothelial dysfunction is present in several cardiovascular diseases. With the production of multiple vasoactive substances the normal endothelium modulates the tone of the underlying vascular smooth muscle. These include endothelium-derived relaxing factors such as prostacyclin (PG1(2)), nitric oxide (NO) and endothelium-derived hyperpolarizing factor (EDHF) and vasoconstrictors such as endothelin-1 and angiotensin II. The antiplatelet, antithrombotic and antifibrinolytic properties of the normal endothelium contribute to the maintenance of the fluidity of the blood. Activation or injury to the endothelial cells disrupts the function of the endothelial cells leading to the development of endothelial dysfunction. Endothelial dysfunction is accompanied by vasospasm, thrombosis, and atherosclerosis. It is present in cardiovascular diseases such as hypertension, atherosclerotic heart diseases, congestive heart failure and many others. It has been shown that some therapeutic effects of drugs such as angiotensin-enzyme inhibitors is in part due to the overcoming of endothelial dysfunction.