Cholesteryl ester transfer and cholesterol esterification in type 1 diabetes: relationships with plasma glucose

The activities of two crucial enzymes of reverse cholesterol transport, cholesterol ester transfer protein (CETP) and lecithin:cholesterol acyltransferase (LCAT), and their relationships with lipid profile and fasting plasma glucose were examined in 35 type 1 diabetic children. The CETP and LCAT activities were significantly lower (p<0.05) in the 4 subjects with normal fasting plasma glucose levels (<6.39 mmol/l) than in the 28 with high plasma glucose levels (CEPT activity, 10.63+/-3.81 vs. 32.18+/-13.94 nmol/ml h; LCAT activity, 25.52+/-4.53 vs. 39.52+/-12.52 nmol/ml h; both p<0.05). The subjects with high plasma glucose levels also had higher total and LDL-cholesterol than those with normal glucose levels. CETP activity was positively correlated with fasting plasma glucose, CETP concentration, LCAT activity, total cholesterol, free cholesterol, LDL-C, and LDL-cholesteryl ester, while negatively correlated with cholesteryl ester to free cholesterol ratio, LDL triglyceride to protein ratio, and LDL triglyceride to cholesteryl ester ratio. LCAT activity was found to positively correlate with CETP activity, total cholesterol, free cholesterol, LDL-C, CETP concentration, and LDL-cholesteryl ester, while it negatively correlated with cholesteryl ester to free cholesterol ratio. The results observed in type 1 diabetic subjects suggest that (I) accelerated LCAT and CETP activities may result in the accumulation of LDL-cholesteryl ester; and (2) fasting plasma glucose may be a major determinant of CETP activity.