Functional and morphological changes of arterial endothelial cells in chronic hypertension.

(1)Endothelial cells of both the aorta and cerebral microvessels in spontaneously hypertensive rats (SHR) proved to have increased turn-over rateds compared with those in the controls.(2)The activity of endothelial cell-derived growth factors (ECDGFs) in cultured aortic endothelial cells fro SHR was studied by bioassaying the proliferative effect of endothelial cellconditioned medium on vascular smooth muscle cells, fibroblasts and astrocytes. Such cells treated with the conditioned medium showed an accelerated proliferation compared with controls.(3)PDGF-B chainrelated growth factor proved to constitute a major portion of the mitogenic activity of the conditioned media of endothelial cells from both SHR and the control rats.(4)Nothern analysis revealed that the expression of PDGF-B chain was markedly enhanced in cultured endothelial cells of SHR.(5)The fact that the release of ECDGFs from cultured aortic endothelial cells was markedly increased by treatment with a tumor-promoting phorbol ester indicates the participation of protein kinase C in the regulation of release of ECDGFs from the endothelial cells. Based on our above-mentioned findings, we may suppose that the increased growth factors, such as PDGF.B chanin and others, are produced and released in chronic hypertension and they play an important role in the pathogeneses of atherosclerosis and hypertensive arteriolosclerosis.