Abstract P332: Effects of Intravenous Infusion of Polyunsaturated Fatty Acids and Dextrose on Blood Pressure and Endothelial Function in Obese Subjects

Hyperglycemia and elevated free fatty acids (FFAs) are implicated in the development of hypertension and endothelial dysfunction. We recently reported that 8-hour infusion of soy-bean oil containing polyunsaturated fatty acids (Intralipid) results in the elevation of blood pressure (BP) and endothelial dysfunction in obese healthy subjects. However, the effects of dextrose infusion or combination of dextrose and Intralipid on BP, endothelial function and insulin action are not known. Accordingly, we compared the effects of 8-hour infusion of normal saline at 40 ml/hr, Intralipid 20% at 40 mL/hr, dextrose 10% at 40 ml/hr and combination of Intralipid and dextrose on BP, endothelial function in 12 obese healthy subjects [ages:41±7 yrs, BMI:32±2 kg/m 2 , BP:113/65 mmHg, HOMA-IR: 2.0±1.0]. Blood pressure, brachial artery flow-mediated dilatation (FMD), and levels of FFAs, glucose, and insulin were measured at 0, 4 and 8 h of infusion. Intralipid infusion significantly increased BP, decreased FMD, and increased plasma FFAs (Table). Unlike Intralipid alone, the combination of Intralipid and dextrose did not increase BP but resulted in FMD changes similar to Intralipid alone. Levels of plasma glucose and insulin increased over time after dextrose infusion alone or in combination with Intralipid but not with lipid infusion alone. Compared with Intralipid, the addition of dextrose to Intralipid led to restoration of FFAs to normal level. In summary, Intralipid but not dextrose infusion alone or in combination with Intralipid results in significant elevation in blood pressure in obese healthy subjects. In contrast, dextrose administration had no effect on Intralipid-induced endothelial dysfunction. The mechanisms underlying differences in vascular response after addition of dextrose to Intralipid are not known, but these results indicate that dextrose-induced mild hyperinsulinemia may regulate adverse hemodynamic effects of fat administration in obese subjects.