Abstract P139: Diet-induced Shifts In HDL Profiles Are Associated With Changes In Immune Parameters

Abstract

Introduction: Preclinical and population-based studies have demonstrated immunomodulatory and anti-inflammatory properties of HDL; however, it is unclear whether diet-induced changes in HDL profiles can directly impact markers of immune inflammation. Hypothesis: We hypothesized that daily consumption of different egg-based diets, which have been shown to differentially impact serum lipids and lipoprotein profiles, would induce changes in HDL parameters that correspond to shifts in clinical and molecular immune markers. Methods: Healthy men and women (18-35y, BMI < 30kg/m 2 or < 30% body fat for men and < 40% body fat for women, n = 26) participated in a 16-week randomized, crossover intervention trial (NCT03577223), in which they consumed an egg-free diet for 4 weeks, followed by a 4-week diet containing either 3 whole eggs or 3 egg whites per day. Participants then followed a 4-week egg-free diet washout period, before switching to the alternative whole egg or egg white diet treatment. Fasting lipoprotein profiles, complete blood cell counts, and gene expression in peripheral blood mononuclear cells (PBMCs) was measured at the end of each diet period. Results: While no changes in total HDL particles, average HDL particle diameter, or the concentration of small (7.4-8.0 nm) or medium (8.1-9.5 nm) HDL particles was observed, the concentration of large HDL particles (10.8nm) was increased by whole egg intake as compared to intake of egg whites. A trend toward increased apolipoprotein A1 during the whole egg diet period as compared to the egg-free diet period was additionally observed. In line with our hypothesis, changes in large HDL concentrations between whole egg vs. egg white periods were inversely correlated with total white blood cell counts and absolute lymphocyte counts. CD8A mRNA expression in PBMCs was inversely correlated with concentrations of total and large HDL particles. Importantly, while serum choline and betaine were increased by whole egg intake compared to the other diet periods, no differences in pro-atherogenic and inflammatory trimethylamine-N-oxide (TMAO) between diet periods was observed. Conclusion: These findings suggest that diet-induced changes in HDL profiles are directly associated with changes in immune parameters.