Demonstration of endothelial-activating properties of hypertensive sera.

Sera from patients with hypertension were examined for their ability to influence endothelial cell function. Sera from 10 patients with hypertension and from 11 age-matched controls were incubated with endothelial cells and their effect on cell growth assessed by endothelial cell 3H-thymidine uptake. Sera from patients with hypertension had a more pronounced stimulatory effect on endothelial cell proliferation than control sera. In addition, hypertensive sera were also examined for their capacity to stimulate endothelial cell production of the vasoactive peptide endothelin. Confluent monolayers of endothelial cells were incubated with sera and the amount of endothelin generated in the supernatant measured by an immunoassay. Amounts of endothelin produced by the endothelial cells in response to hypertensive sera were significantly higher compared with the amounts produced in response to normal sera. The results of the studies suggest that a serum factor(s) in hypertensive patients may be of importance in modulating endothelial cell function. Such a factor(s) may have a significant role in the pathogenesis of hypertension.