Lian_2012_Circ.Res_111_982

RATIONALE: Carboxylesterase 3/triacylglycerol hydrolase (TGH) has been shown to participate in hepatic very low-density lipoprotein (VLDL) assembly. Deficiency of TGH in mice lowers plasma lipids and atherogenic lipoproteins without inducing hepatic steatosis. OBJECTIVE: To investigate the contribution of TGH to atherosclerotic lesion development in mice that lack low-density lipoprotein receptor (LDLR). METHODS AND
RESULTS: Mice deficient in LDL receptor (Ldlr(-/-)) and mice lacking both TGH and LDLR (Tgh(-/-)/Ldlr(-/-)) were fed with a Western-type diet for 12 weeks. Analysis of Tgh(-/-)/Ldlr(-/-) plasma showed an atheroprotective lipoprotein profile with decreased cholesterol in the VLDL and the LDL fractions, concomitant with elevated high-density lipoprotein cholesterol. Significantly reduced plasma apolipoprotein B levels were also observed in Tgh(-/-)/Ldlr(-/-) mice. Consequently, Tgh(-/-)/Ldlr(-/-) mice presented with a significant reduction (54%, P<0.01) of the high-fat, high-cholesterol dieteninduced atherosclerotic plaques when compared with Tgh(+/+)/Ldlr(-/-) mice in the cross-sectional aortic root analysis. TGH deficiency did not further increase liver steatosis despite lowering plasma lipids, mainly due to reduced hepatic lipogenesis. The ameliorated dyslipidemia in Tgh(-/-)/Ldlr(-/-) mice was accompanied with significantly improved insulin sensitivity.
CONCLUSIONS: Inhibition of TGH activity ameliorates atherosclerosis development and improves insulin sensitivity in Ldlr(-/-) mice.