Study of Lipoprotein, especially VLDL Apolipoprotein E in Patients with Angiographically Defined Coronary Atherosclerosis

Lipid status and Apolipoprotein E (Apo E) were analyzed in consecutive 183 patients undergoing selective coronary cineangiography. The subjects consisted of 53 controls with normal intact coronary artery (Control) and 130 patients with coronary atherosclerosis (CAD), who were subdivided into three groups (mild, moderate, and severe) according to coronary atherosclerosis score (CAS). Total cholesterol (T-CH) and triglyceride (T-TG) were significantly higher in severe group (216±32, 128±44mg/dl) than in Control (191±33, 104±45mg/dl), but T-CH and T-TG of mild group (190±28, 116±43mg/dl) were not significantly different from those of Control. VLDL Apo E_2/E_3 ratio was significantly higher in mild, moderate, and severe groups (0.554±0.159, 0.569±0.179, and 0.549±0.142, respectively) than in Control (0.467±0.146), irrespective of the extent of coronary atherosclerosis (p<0.005). Even in case the patients with coronary atherosclerosis were classified into three groups according to the numbers of affected coronary arteries, T-CH, T-TG, and Apo E_2/E_3 ratio showed the similar relation among, the groups. Furthermore, we examined VLDL-CH and VLDL-TG in 61 patients and 27 controls. VLDL-CH, VLDL-TG, and VLDL-CH×(VLDL-CH/VLDL-TG) were significantly higher in CAD (24.6±13.9, 75.4±40.4, and 11.2±8.8 mg/dl, respectively) than in Control (18.9±10.8, 61.4±51.9, and 9.0±4.5 mg/dl, respectively: p<0.05: Wilcoxon's test). Moreover, serum Apo E concentration was determined in 42 patients and 21 controls. These values were not significantly different between two groups (CAD: 4.64±1.40, Control: 4.65±0.99mg/dl) On discriminant analysis of T-CH, T-TG, and VLDL Apo E_2/E_3 ratio, VLDL Apo E_2/E_3 ratio was the best discriminator for predicting of the presence of coronary atherosclerosis, (discriminative value: 5.74, 0.74, and 8.60, respectively). In conclusion, elevated Apo E_2/E_3 ratio may play an important role in genesis of coronary atherosclerosis.