High fat challenges with different fatty acids affect distinct atherogenic gene expression pathways in immune cells from lean and obese subjects

Early perturbations in vascular health can be detected by imposing subjects to a high fat (HF) challenge and measure response capacity. Subtle responses can be determined by assessment of whole-genome transcriptional changes. We aimed to magnify differences in health by comparing gene-expression changes in peripheral blood mononuclear cells (PBMCs) towards a high MUFA or SFA challenge between subjects with different cardiovascular disease risk profiles and to identify fatty-acid specific gene-expression pathways. METHODS AND RESULTS: In a cross-over study, 17 lean and 15 obese men (50-70y) received two 95g fat shakes, high in SFAs or MUFAs. PBMC gene-expression profiles were assessed fasted and 4h postprandially. Comparisons were made between groups and shakes. During fasting, 294 genes were significantly different expressed between lean and obese. The challenge increased differences to 607 genes after SFA and 2516 genes after MUFA. In both groups, SFA decreased expression of cholesterol biosynthesis and uptake genes and increased cholesterol efflux genes. MUFA increased inflammatory genes and PPARα targets involved in β-oxidation. CONCLUSION: Based upon gene-expression changes, we conclude that a HF challenge magnifies differences in health, especially after MUFA. Our findings also demonstrate how SFAs and MUFAs exert distinct effects on lipid handling pathways in immune cells. In a double-blind cross-over study, 17 lean and 15 obese men (aged 50-70y) received two high-fat milkshakes containing 95g fat, either high in saturated (SFA) or monounsaturated (MUFA) fatty acids. PBMC gene expression profiles were determined before and 4h after shake consumption.