Protection From Obesity in Mice Lacking the VLDL Receptor

Abstract

It has previously been reported that mice lacking the VLDL receptor (VLDLR−/−) exhibit normal plasma lipid levels and a modest decrease in adipose tissue mass. In the present study, the effect of VLDLR deficiency on profound weight gain was studied in mice. Obesity was induced either by feeding of a high-fat, high-calorie (HFC) diet or by crossbreeding mice onto the genetically obese ob / ob background. After 17 weeks of HFC feeding, VLDLR−/− mice remained lean, whereas their wild-type littermates (VLDLR+/+) became obese. Similarly, the weight gain of ob / ob mice was less profound in the absence of the VLDLR. Moreover, VLDLR deficiency led to increased plasma triglycerides after HFC feeding. The protection from obesity in VLDLR−/− mice involved decreased peripheral uptake of fatty acids, because VLDLR−/− mice exhibited a significant reduction in whole-body free fatty acid uptake, with no clear differences in food intake and fat absorption. These observations were supported by a strong decrease in average adipocyte size in VLDLR−/− mice of both obesity models, implying reduced adipocyte triglyceride storage in the absence of the VLDLR. These results suggest that the VLDLR plays a role in the delivery of VLDL-derived fatty acids into adipose tissue.