Cholesteryl ester transfer protein (CETP) (also called plasma lipid transfer protein) is a plasmaprotein that facilitates the transport of cholesteryl esters and triglycerides between the lipoproteins. It collects triglycerides from very low density or low density lipoproteins (VLDL or LDL) and exchanges them for cholesteryl esters from high density lipoproteins (and vice versa). Most of the time, however, CETP does a homoexchange- trading a triglyceride for a triglyceride or a cholesteryl ester for a cholesteryl ester.
The CETP gene is located on the sixteenth chromosome (16q21).
Role in disease
Rare mutations leading to increased function of CETP have been linked to accelerated atherosclerosis.[1] In contrast, a polymorphism (I405V) of the CETP gene leading to lower serum levels has also been linked to exceptional longevity.[2] However, this mutation also increases the prevalence of coronary heart disease in patients with hypertriglyceridemia.[3] The D442G mutation, which lowers CETP levels and increases HDL levels also increases coronary heart disease.[1]
As HDL has a protective function in atherosclerosis and cardiovascular disease, and certain disease states (such as the metabolic syndrome) feature low HDL, pharmacological inhibition of CETP is being studied as a method to improve HDL levels.[5] Specifically, the small molecular agent torcetrapib was shown to increase HDL levels (alone and with a statin) and lower LDL (when co-administered with a statin) in a 2004 study.[6] Studies into cardiovascular endpoints, however, were largely disappointing; while they confirmed the change in lipid levels, most reported an increase in blood pressure, no change in atherosclerosis,[7][8] and (in a trial of a combination of torcetrapib and atorvastatin) an increase in cardiovascular events and mortality.[9]
A compound related to torcetrapib, going by the investigative name JTT-705/R1658, is undergoing studies.[10] It increases HDL levels by 30% (as compared to 60% by torcetrapib).[11]. Another CETP inhibitor under development is Merck's MK-0859 anacetrapib, which in initial studies has been shown not to increase blood pressure.[12]
^ Bruce C, Sharp DS, Tall AR (May 1998). "Citation is missing a title. Either specify one, or click here and a bot will try to complete the citation details for you.[1]". J Lipid Res39 (5): 1071–8. PMID 9610775.
^ Abbey M, Nestel PJ (1994). "Plasma cholesteryl ester transfer protein activity is increased when trans-elaidic acid is substituted for cis-oleic acid in the diet". Atherosclerosis106 (1): 99–107. doi:10.1016/0021-9150(94)90086-8. PMID 8018112.
^ El Harchaoui K, van der Steeg WA, Stroes ES, Kastelein JJ (Aug 2007). "The role of CETP inhibition in dyslipidemia". Curr Atheroscler Rep9 (2): 125–33. doi:10.1007/s11883-007-0008-5. PMID 17877921.
Okajima F (2002). "[Distribution of sphingosine 1-phosphate in plasma lipoproteins and its role in the regulation of the vascular cell functions]". Tanpakushitsu Kakusan Koso47 (4 Suppl): 480–7. PMID 11915346.
Barter PJ, Brewer HB, Chapman MJ, et al. (2003). "Cholesteryl ester transfer protein: a novel target for raising HDL and inhibiting atherosclerosis". Arterioscler. Thromb. Vasc. Biol.23 (2): 160–7. PMID 12588754.
Dallinga-Thie GM, Dullaart RP, van Tol A (2007). "Concerted actions of cholesteryl ester transfer protein and phospholipid transfer protein in type 2 diabetes: effects of apolipoproteins". Curr. Opin. Lipidol.18 (3): 251–7. doi:10.1097/MOL.0b013e3280e12685. PMID 17495597.