A possible role of catecholamines in atherogenesis and subsequent complications of atherosclerosis

Cultured smooth muscle cells (SMC) from rat aorta and endothelial cells (EC) from pig aorta were used to study the effect of the catecholamines epinephrine and norepinephrine on cell proliferation. Both stimulated growth of SMC and EC when added to the culture medium. Besides epinephrine and norepinephrine, dopamine and some of their metabolites also stimulated proliferation of cultured endothelial cells. Smooth muscle cells originating from rats being exposed to atherosclerotic risk factors, like diabetes, hypertension and balloon-injury, exhibited an increased susceptibility to these catecholamines compared to SMC from control animals. In comparison to normotensive control animals a 10-fold elevated plasma concentration of epinephrine was found in hypertensive rats. In man plasma epinephrine and norepinephrine concentration was determined in a healthy control group and in patients suffering from diabetes mellitus and coronary artery disease. Plasma epinephrine and norepinephrine levels were similar in patients suffering from diabetes mellitus compared to the control group. But in patients with coronary artery disease significantly higher plasma concentrations for epinephrine (p < 0.001) and norepinephrine (p < 0.01) were observed. These data support the hypothesis that catecholamines may play a role in the development and subsequent complications of atherosclerosis.