Abstract 458: A Study Of Short-term Low-saturated Fat Versus High-saturated Fat Diet In Atherothrombosis Risk Factors In Subjects With Hypertriglyceridemia

Abstract

Introduction: Dietary fat and composition may impact the risk of atherosclerotic cardiovascular disease (ASCVD) in subjects with hypertriglyceridemia (HTG). Hypothesis: We hypothesized that a low-saturated fat diet (LSFD), in contrast to a high-saturated fat diet (HSFD), improves blood lipid levels and reduces atherothrombosis risk factors in subjects with HTG. Method: Subjects with HTG and metabolic syndrome (n=19) were randomly placed on an LSFD (~25% of calories from fat, 5% from saturated fat) or an HSFD (~52% of calories from fat, 25% from saturated fat) for 4 days (day 1-4) and a breakfast on day 5 and then switched to the other diet after a 4- to 6-week washout period. Blood was collected on day 1 fasting before the start of the diet and on day 5 fasting and at 4 and 6 hours after breakfast. Lipid profiles and flow cytometry to measure monocyte intracellular lipid accumulation, monocyte expression of tissue factor (TF), and monocyte-platelet aggregates (MPAs) were performed. Results: On day 5, LSFD, compared to HSFD, induced lower plasma levels of postprandial total triglyceride and LDL-triglyceride and fasting and postprandial total cholesterol, non-HDL-cholesterol, LDL-cholesterol, and small dense LDL-cholesterol. Classical and intermediate monocytes with LSFD, in contrast to HSFD, exhibited reduced intracellular lipid accumulation indicated by decreases in cellular granularity and nile red staining examined by flow cytometry. LSFD vs. HSFD also reduced classical monocyte uptake of oxidized LDL ex vivo at 4 hours postprandially on day 5. Surface level of TF was higher on classical and intermediate monocytes than on nonclassical monocytes assessed by mean fluorescence intensity. Classical and intermediate monocytes, compared to nonclassical monocytes, were also more prone to form aggregates with platelets. However, there was no significant difference between LSFD and HSFD in TF levels on any monocyte subsets and in MPAs of any monocyte subsets at any time points recorded. Conclusion: In subjects with HTG and metabolic syndrome, short-term LSFD, in contrast to HSFD, reduced monocyte lipid accumulation and oxidized LDL uptake but did not induce significant differences in monocyte surface levels of TF and MPA formation.