Serum nitric oxide levels in patients with coronary artery disease

Nitric oxide (NO) plays a pivotal role in the pathophysiology of coronary artery disease. The roles of NO are not only physiological but also pathological in the cardiovascular system. An inappropriate release of NO has been linked to the pathogenesis of CAD. The authors investigated whether serum NOx (nitrate and nitrite), a stable end product of NO, level was related to patients with coronary artery disease. The blood chemistry, such as cholesterol, triglyceride, LDL-C, HDL-C and blood sugar, was also measured in comparison with serum NOx. Serum NOx was measured in samples from 20 healthy controls, 20 angina patients without angiographic evidence of coronary lesions (CAG) and 20 angina patients with angiographic evidence of coronary lesions (CAD) by using modified Griess reaction. The mean serum NOx levels in the CAD groups was higher than CAG and control groups (41.3 +/- 5.5, 32.7 +/- 3.9 and 25.7 +/- 3.5 micromol/L, respectively). NOx levels in the CAD group was only significantly higher than the control groups (p < 0.05) but not the CAG groups. There were no significant differences of NOx levels in all age groups. In the CAD group, women showed significantly higher NOx levels than men (64.0 +/- 7.5 and 29.0 +/- 4.7 microl/L, respectively, p < 0.05). Interestingly, the mean serum NOx levels in the CAD groups was significantly higher in a group of abnormal lipid profiles (cholesterol, triglyceride, LDL-C) and blood sugar than in a group of normal profiles. The results suggested that there was an increased NOx levels in patients with coronary artery disease and much higher in patients with multiple underlying conditions such as hyperlipidemia and hyperglycemia. Thus, the measurement of the NOx levels at different times may help to monitor the state and severity of coronary artery disease.