Vasoactive factors and growth factors alter vascular smooth muscle cell EC-SOD expression.

Oxygen free radicals have been suggested to play important roles in atherogenesis and other pathological processes in the blood vessel wall. The vascular wall contains large amounts of extracellular superoxide dismutase (EC-SOD), which is produced and secreted to the extracellular space by smooth muscle cells. In this study, we investigated the influence of factors regulating tension and proliferation of vascular smooth muscle cells and of some interstitial matrix components on EC-SOD expression. The expression and secretion of EC-SOD were upregulated by histamine, vasopressin, oxytocin, endothelin-1, angiotensin II, serotonin, heparin, and heparan sulfate and were downregulated by platelet-derived growth factors-AA and -BB, acidic and basic fibroblast growth factors, and epidermal growth factor. The responses were slow and developed over several days. The findings suggest that various physiological and pathological conditions might markedly influence EC-SOD expression, significantly altering the susceptibility of the vascular wall to effects of the superoxide radical.