HEART CD36 EXPRESSION IS INCREASED IN MURINE MODELS OF DIABETES AND IN MICE FED A HIGH-FAT DIET

High levels of CD36 expression are found in triglyceride storing and s ecreting cells such as differentiated adipocytes and mammary secretory epithelial cells and in some capillary endothelial cells. We have fou nd high levels of CD36 in the capillary endothelium of murine adipose tissue and in cardiac and skeletal muscles, Muscle cells themselves we re CD36 negative, No CD36 was found in brain endothelium. Cardiac and skeletal muscle tissues are highly oxidative and catabolize long-chain fatty acids as a source of energy while brain tissue does not use lon g-chain fatty acids for energy production, Since capillary endothelial cell CD36 expression appeared to correlate with parenchymal cell fatt y acid utilization and since CD36 has been identified recently as a lo ng-chain fatty acid-binding protein, we examined heart tissue CD36 exp ression in murine models of insulin-dependent (nonobese diabetic, NOD) and non-insulin-dependent diabetes mellitus (KKA(Y)). Diabetic NOD an d KKA(Y) mice had serum triglyceride levels 2.6- and 4.2-fold higher, respectively, than normal mice and exhibited 7- and 3.5-fold higher le vels of heart microsomal CD36, respectively, than control mice. Mice f ed a 40% fat diet expressed heart tissue CD36 at a level 3.5-fold high er than those fed a 9% fat diet. These data suggest that endothelial c ell CD36 expression is related to parenchymal cell lipid metabolism.