Suppression of hepatic cholesteryl ester transfer protein expression in obese humans with the development of type 2 diabetes mellitus.

Cholesteryl ester transfer protein (CETP) is a plasma enzyme that can modulate the profile of lipoproteins and is thus considered: 1) a mediator of vascular disease; and 2) a therapeutic target for vascular disease. In the present study, we pursued a better understanding of the effect of type 2 diabetes on the expression of CETP in obese patients. Obesity was accompanied by a 20% elevation in plasma CETP that was eliminated with the development of diabetes. These differences were observed for both men and women and were due to variations in the amount of CETP protein in the plasma. The mRNA and protein of both the full-length (CETPFL) and alternatively spliced (CETPDelta9) forms of CETP were lower in the liver, but not in either sc or omental adipose tissue depots, of diabetic obese subjects. Sterol response element binding proteins 1 and 2 were also lower in liver homogenates, suggesting that these transcription factors may mediate the effects of type 2 diabetes on hepatic CETP expression. Thus, the suppressive effects of type 2 diabetes in obese subjects are observed in both men and women and may be due, at least in part, to a suppression of hepatic CETP expression.

Cholesteryl ester transfer protein expression prevents diet-induced atherosclerotic lesions in male db/db mice.

OBJECTIVE: Accompanying more atherogenic lipoprotein profiles and an increased incidence of atherosclerosis, plasma cholesteryl ester transfer protein (CETP) is depressed in diabetic obese patients compared with nondiabetic obese counterparts. The depressed levels of CETP in the plasma of diabetic obese individuals may contribute to the development of an atherogenic lipoprotein profile and atherogenesis. We have examined the effect of CETP expression on vascular health in the db/db model of diabetic obesity. METHODS AND RESULTS: Transgenic mice expressing the human CETP minigene were crossed with db/db strain, and 3 groups of offspring (CETP, db, and db/CETP) were placed on an atherogenic diet for 16 weeks. The proximal aorta was then excised and examined for the presence of atherosclerotic plaques. In db mice, 9 of 11 had intimal lesions with a mean area of 26 098+/-7486 microm2. No lesions greater than 1000 microm2 were observed in db/CETP or CETP mice. CETP-expressing mice had lower circulating cholesterol concentrations than db mice. Fractionating plasma lipids by FPLC indicated that the difference in total cholesterol was primarily attributable to differences in VLDL and LDL. CONCLUSIONS: The expression of human CETP in db/db mice prevented the formation of diet-induced lesions, suggesting an antiatherogenic effect of CETP in the context of diabetic obesity.