Replacing Saturated Fat With Unsaturated Fat in Western Diet Reduces Foamy Monocytes and Atherosclerosis in Male Ldlr-/- Mice.

OBJECTIVE: A Mediterranean diet supplemented with olive oil and nuts prevents cardiovascular disease in clinical studies, but the underlying mechanisms are incompletely understood. We investigated whether the preventive effect of the diet could be due to inhibition of atherosclerosis and foamy monocyte formation in Ldlr-/- mice fed with a diet in which milkfat in a Western diet (WD) was replaced with extra-virgin olive oil and nuts (EVOND). Approach and Results: Ldlr-/- mice were fed EVOND or a Western diet for 3 (or 6) months. Compared with the Western diet, EVOND decreased triglyceride and cholesterol levels but increased unsaturated fatty acid concentrations in plasma. EVOND also lowered intracellular lipid accumulation in circulating monocytes, indicating less formation of foamy monocytes, compared with the Western diet. In addition, compared with the Western diet, EVOND reduced monocyte expression of inflammatory cytokines, CD36, and CD11c, with decreased monocyte uptake of oxLDL (oxidized LDL [low-density lipoprotein]) ex vivo and reduced CD11c+ foamy monocyte firm arrest on vascular cell adhesion molecule-1 and E-selectin-coated slides in an ex vivo shear flow assay. Along with these changes, EVOND compared with the Western diet reduced the number of CD11c+ macrophages in atherosclerotic lesions and lowered atherosclerotic lesion area of the whole aorta and aortic sinus. CONCLUSIONS: A diet enriched in extra-virgin olive oil and nuts, compared with a Western diet high in saturated fat, lowered plasma cholesterol and triglyceride levels, inhibited foamy monocyte formation, inflammation, and adhesion, and reduced atherosclerosis in Ldlr-/- mice.

TAp63 contributes to sexual dimorphism in POMC neuron functions and energy homeostasis.

Sexual dimorphism exists in energy balance, but the underlying mechanisms remain unclear. Here we show that the female mice have more pro-opiomelanocortin (POMC) neurons in the arcuate nucleus of hypothalamus than males, and female POMC neurons display higher neural activities, compared to male counterparts. Strikingly, deletion of the transcription factor, TAp63, in POMC neurons confers "male-like" diet-induced obesity (DIO) in female mice associated with decreased POMC neural activities; but the same deletion does not affect male mice. Our results indicate that TAp63 in female POMC neurons contributes to the enhanced POMC neuron functions and resistance to obesity in females. Thus, TAp63 in POMC neurons is one key molecular driver for the sexual dimorphism in energy homeostasis.

Lipidomic analyses of female mice lacking hepatic lipase and endothelial lipase indicate selective modulation of plasma lipid species.

Hepatic lipase (HL) and endothelial lipase (EL) share overlapping and complementary roles in lipoprotein metabolism. The deletion of HL and EL alleles in mice raises plasma total cholesterol and phospholipid concentrations. However, the influence of HL and EL in vivo on individual molecular species from each class of lipid is not known. We hypothesized that the loss of HL, EL, or both in vivo may affect select molecular species from each class of lipids. To test this hypothesis, we performed lipidomic analyses on plasma and livers from fasted female wild-type, HL-knockout, EL-knockout, and HL/EL-double knockout mice. Overall, the loss of HL, EL, or both resulted in minimal changes to hepatic lipids; however, select species of CE were surprisingly reduced in the livers of mice only lacking EL. The loss of HL, EL, or both reduced the plasma concentrations for select molecular species of triacylglycerol, diacylglycerol, and free fatty acid. On the other hand, the loss of HL, EL, or both raised the plasma concentrations for select molecular species of phosphatidylcholine, cholesteryl ester, diacylglycerol, sphingomyelin, ceramide, plasmanylcholine, and plasmenylcholine. The increased plasma concentration of select ether phospholipids was evident in the absence of EL, thus suggesting that EL might exhibit a phospholipase A2 activity. Using recombinant EL, we showed that it could hydrolyse the artificial phospholipase A2 substrate 4-nitro-3-(octanoyloxy)benzoic acid. In summary, our study shows for the first time the influence of HL and EL on individual molecular species of several classes of lipids in vivo using lipidomic methods.