Vitamin C, diclophenac, and l-arginine protect endothelium-dependent vasodilation against elevated circulating fatty acid levels in humans

An acute elevation of circulating non-esterified fatty acids (NEFAs) has previously been shown to impair endothelium-dependent vasodilation (EDV). In this study, we investigated if local administration of vitamin C ( n=8, 18 mg/min), l-arginine ( n=8, 12.5 mg/min), or the cyclooxygenase (COX) inhibitor diclophenac ( n=8, 0.5 mg/min) can counteract the endothelial dysfunction seen during infusion of Intralipid® plus heparin ( n=10). EDV and endothelium-independent vasodilation (EIDV) were studied in the forearm after local administration of methacholine chloride (Mch; 2 and 4 μg/min) and sodium nitroprusside (SNP; 5 and 10 μg/min). Forearm blood flow (FBF) was determined with venous occlusion plethysmography. Intralipid® and heparin increased circulating NEFA levels sevenfold and impaired EDV ( P