Rabbit Anti-Mouse PLTP (a.a. 170-270) Polyclonal antibody

Objective: In addition to lowering low-density lipoprotein (LDL)-cholesterol, statins modestly increase high-density lipoprotein (HDL)cholesterol in humans and decrease cholesteryl ester transfer protein (CETP) mass and activity. Our aim was to determine whether the increase in HDL depends on CETP expression. Methods and results: APOE*3-Leiden (E3L) mice, with a human-like lipoprotein profile and a human-like responsiveness to statin treatment, were crossbred with mice expressing human CETP under control of its natural flanking regions resulting in E3L.CETP mice. E3L and E3L. CETP mice were fed a Western-type diet with or without atorvastatin. Atorvastatin (0.01% in the diet) reduced plasma cholesterol in both E3L and E3L.CETP mice (-26 and -33%, P < 0.05), mainly inVLDL, but increased HDL-cholesterol only in E3L.CETP mice (+52%). Hepatic mRNA expression levels of genes involved in HDL metabolism, such as phospholipid transfer protein (Pltp), ATP-binding cassette transporter AI (Abcal), scavenger receptor class B type I (Sr-bl), and apolipoprotein AI (Apoal), were not differently affected by atorvastatin in E3L..CETP mice as compared to E3L mice. However, in E3L.CETP mice, atorvastatin down-regulated the hepatic CETP mRNA expression (-57%; P < 0.01) as well as the total CETP level (-29%) and cholesteryl esters (CE) transfer activity (-36%; P < 0.05) in plasma. Conclusions: Atorvastatin increases HDL-cholesterol in E3L.CETP mice by reducing the CETP-dependent transfer of cholesterol from HDL to (V)LDL, as related to lower hepatic CETP expression and a reduced plasma (V)LDL pool. (c) 2007 Elsevier Ireland Ltd. All rights reserved.

Objective. Studies in mice suggest that plasma apoM is lowered in hyperinsulinaemic diabetes and that apoM stimulates formation of pre-beta-HDL. Pre-beta-HDL is an acceptor of cellular cholesterol and may be critical for reverse cholesterol transport. Herein, we examined whether patients with type 2 diabetes have reduced plasma apoM and whether apoM is associated with pre-beta-HDL formation and cellular cholesterol efflux. Design. In 78 patients with type 2 diabetes and 89 control subjects, we measured plasma apoM with ELISA, pre-beta-HDL and pre-beta-HDL formation, phospholipid transfer protein (PLTP) activity and the ability of plasma to promote cholesterol efflux from cultured fibroblasts. Results. ApoM was similar to 9% lower in patients with type 2 diabetes compared to controls (0.025 +/- 0.006 vs. 0.027 +/- 0.007 g L-1, P = 0.01). The difference in apoM was largely attributable to diabetes-associated obesity. ApoM was positively related to both HDL (r = 0.16; P = 0.04) and LDL cholesterol (r = 0.28; P = 0.0003). Pre-beta-HDL and pre-beta-HDL formation were not different between diabetic and control subjects. ApoM predicted pre-beta-HDL (r = 0.16; P = 0.04) and pre-beta-HDL formation (r = 0.19; P = 0.02), even independently of positive relationships with apoA-I, HDL-cholesterol and PLTP activity. Cellular cholesterol efflux to plasma was positively related to pre-beta-HDL and PLTP activity but not significantly to apoM. Conclusions. Plasma apoM is modestly reduced in type 2 diabetes. Pre-beta-HDL and pre-beta-HDL formation are positively associated with apoM, supporting the hypothesis that apoM plays a role in HDL remodelling in humans. Lower apoM may provide a mechanism to explain why pre-beta-HDL formation is not increased in type 2 diabetes despite elevated PLTP activity.