Smooth muscle proliferation in hypertension. State-of-the-art lecture.

Similar pathologic changes in atherosclerosis and hypertension suggest that some common mechanisms may underlie these two major vascular diseases. Both diseases are characterized by smooth muscle proliferation. The atherosclerotic lesion is characterized by proliferation of smooth muscle cells in the arterial intima of large arteries, leading to vascular occlusion, lipid accumulation, and thrombosis. Smooth muscle proliferation in hypertensive vascular disease again results in increased wall mass and a narrowed lumen. The small vessel change is though to be etiologic of the increased peripheral resistance of high blood pressure. At least in large vessels, the form of proliferation is quite different. Atherosclerosis shows a true cell proliferation. In contrast, smooth muscle cells from animals with hypertensive vascular disease show DNA replication without mitosis. The resulting endoreplication is suggestive of the forms of replication seen in differentiated sarcomeric muscle, particularly in cardiac myocytes.