Abstract 250: Palmitic Interesterified Fat Induces Atherosclerosis and Inflammatory Cytokine Secretion in LDL Receptor Knockout Mice

Rationale: Interesterified fat was developed to substitute trans fat, once several epidemiological and clinical studies demonstrated its harmful effects on cardiovascular risk. However, the effects of these fats have not yet been completely elucidated. Thus, the aim of this work was to evaluate the effect of interesterified fats containing stearic and palmitic fatty acids on atherosclerosis development and cytokines secretion from peritoneal macrophages isolated from LDLr knockout mice. Protocol: Weaning male LDLr-KO mice were randomly divided into six groups (n=15-20) fed during 16 weeks on a high fat diet (40% of energy as fat) enriched with polyunsaturated (PUFA), TRANS, palmitic (Palm), palmitic interesterified (Palm Inter), stearic (Stear) or stearic interesterified (Stear Inter). Analyses: total plasma cholesterol and triglyceride concentrations, aortic macrophage infiltration (CD68 staining) and atherosclerosis (oil red O), and inflammatory biomarkers secretion were determined. Results: Dietary intake was similar in all groups. Interesterification failed to alter plasma cholesterol concentrations: Palm vs Palm inter (499.2±22.5 vs 526.8±20.7, p>0.05); Stear vs Stear inter (342.6±21.8 vs 363.9±22.5, p>0.05). Similar results were observed for triglycerides: Palm vs Palm inter (309±49 vs 303±33, p>0.05); Stear vs Stear inter (239±28 vs 237±27, p>0.05). As expected, TRANS induced the largest lesion area. However, Palm Inter induced the highest lesion area and macrophage infiltration as compared to Palm, Stear, Stear Inter and PUFA groups. Concerning pro inflammatory cytokines secretion, harmful effects of Palm inter were also observed for IL-6, IL-1β and MCP-1. Conclusion: Interesterified fats containing palmitic acid increased pro inflammatory cytokines secretion that contributed to aortic macrophage infiltration and atherosclerosis development.