Serum from patients with severe CHF downregulates eNOS expression and increases apoptosis. High levels of TNF-alpha likely play a role, but they cannot be the only factor responsible.

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Background-Endothelial apoptosis of atherosclerotic lesions is a possible determinant for the stable-to-vulnerable plaque transition.Recent data support the notion that plaque activation may be a pan-coronary process, advocating the existence of circulating triggers. Methods and Results-Serum from 40 healthy subjects (group 1) and 73 patients with stable angina (nϭ32; group 2) or acute coronary syndromes (nϭ41; group 3) was incubated with human umbilical vein endothelial cells. The percentage of apoptosis by flow cytometry and Fas, Bax, and Bcl-2 protein expression by immunoblotting were evaluated at entry in patients and control subjects and repeated after 12 months in group 3. At baseline, apoptotic nuclei were higher in group 3 (14Ϯ6%) than in group 2 (3.3Ϯ1.8%) and group 1 (1.35Ϯ0.8%) (PϽ0.001). Fas and Bcl-2 were increased in group 3 with respect to groups 1 and 2 (PϽ0.01). Coincubation of group 3 serum with anti-tumor necrosis factor-␣ and anti-interleukin-6 monoclonal antibodies did not affect the human umbilical vein endothelial cell apoptotic process, whereas addition of Trolox decreased apoptosis to Ͻ50%. The percentage of apoptosis in group 3 significantly correlated to the numbers of coronary complex lesions at angiography (rϭ0.58, PϽ0.0005). In group 3, apoptosis and the Bax/Bcl-2 ratio decreased at 1 year (PϽ0.0001, PϽ0.05 respectively). Conclusions-Serum from patients with acute coronary syndromes displays a proapoptotic effect on human endothelial cells, supporting the theory of the existence of circulating triggers potentially able to activate atherosclerotic lesions.