Abstract 784: Eicosapentaenoic Acid, Unlike Other Omega-3 Fatty Acids, Inhibits Membrane Cholesterol Crystalline Domains Under Conditions of Hyperglycemia

Abstract

Prescription eicosapentaenoic acid (EPA) reduced cardiovascular events in the REDUCE-IT study population, including in patients with diabetes. During hyperglycemia, there is abnormal membrane cholesterol aggregation which has been linked to oxidative stress and plaque instability. EPA at a pharmacologic dose may preserve normal cholesterol distribution as compared to other omega-3 fatty acids (FAs), including docosahexaenoic acid (DHA), eicosatriaenoic acid (ETE) and α-linolenic acid (ALA). Membrane vesicles were prepared from dilinoleoylphosphatidylcholine (DLPC) at a cholesterol-to-phospholipid mole ratio of 0.6:1 and treated with the omega-3 FAs under conditions of hyperglycemia (200 mg/dL). Changes in membrane lipid organization and width were measured using small angle X-ray diffraction approaches. Cholesterol domains were identified by the presence of diffraction peaks corresponding to a unit cell periodicity or width of 34 Å. Results showed that only EPA was able to prevent the formation of cholesterol domains and had a membrane structure characterized by a normal width (54 Å) and cholesterol distribution despite hyperglycemia. But samples containing the other FAs had a biphasic membrane structure containing prominent cholesterol crystalline domains. The relative size of the cholesterol domains was greatest in the order of ALA>DHA>ETE. Thus, EPA preserved normal cholesterol distribution under conditions of hyperglycemia in a manner that was not reproduced with other omega-3 FAs. These data indicate differences between these long chain FAs and support a potential benefit for EPA in reducing atherosclerotic disease.