Relationship between ischemic heart disease (THD) and serum lipids, high density lipoprotein (HDL) lipids and lecithin: cholesterol acyl transferase (LCAT) activity was studied.
Serum levels of total cholesterol, free cholesterol and triglyceride in the patients with IHD were significantly higher than those in normal controls (P<0.01). The levels of total cholesterol, free cholesterol and triglyceride in HDL were lower in the patients with IHD than those in normal controls (statistically insignificant). However, ratios of HDL-total cholesterol/serum total cholesterol and HDL-free cholesterol/serum free cholesterol were significantly lower in the patients with IHD than those in normal controls (P<0.02, P<0.05, respectively). It has been proposed that reduction of HDL concentration or HDL/total lipoproteins ratio may accelerate the development of coronary atherosclerosis.
LCAT activity was positively correlated to serum total cholesterol, free cholesterol, triglyceride and phospholipid and free cholesterol/total cholesterol ratio. While, LCAT activity was negatively correlated to HDL-total cholesterol/serum total cholesterol and HDL-free cholesterol/serum free cholesterol ratio.
There was no difference in LCAT activity between the patients with angina pectoris and old myocardial infarction, and normal controls. The patients free of hyperlipidemia, hypertension, obesity, and heavy smoking had a significantly lower LCAT activity than normal controls (P<0.05). These results suggest that a low LCAT activity is a risk factor of coronary atherosclerosis. Thus, HDL and LCAT may be protective system of atherosclerosis that transfer cholesterol from the arterial wall to the liver.
