Nitric Oxide-Mediated Endothlium-Dependent Vasodilation Is Impaired with Borderline High-LDL Cholesterol

The experimental aims of this study were to determine: (1) whether nitric oxide-mediated endothelium-dependent vasodilation is blunted in adult humans with borderline high plasma low-density lipoprotein (LDL)-cholesterol compared with adults with optimal/near optimal LDL-cholesterol levels; and, if so: (2) whether the magnitude of impairment in adults with borderline high LDL-cholesterol is similar to adults with high LDL-cholesterol. Forearm blood flow responses to intraarterial infusions of acetylcholine and sodium nitroprusside were measured in 50 middle-aged (4364 year) adults: 20 in the optimal/near optimal LDL-cholesterol range (<130 mg/dL); 20 with borderline high LDL-cholesterol (130-159 mg/dL); and 10 with high LDL-cholesterol ($160 mg/dL). In addition, blood flow responses to acetylcholine were determined in the absence and presence of the endothelial nitric oxide synthase inhibitor NG-monomethyl-L-arginine (L-NMMA). Vasodilation to acetylcholine was similar to 20% lower (p < 0.05) in the borderline high (from 4.3 +/- 0.2 to 12.3 +/- 0.8 mL/100 mL tissue/min) and high (from 4.3 +/- 0.3 to 12.0 +/- 0.5 mL/100 mL tissue/min) LDL-cholesterol groups compared with the optimal/near optimal (from 4.4 +/- 0.2 to 14.5 +/- 0.5 mL/100 mL tissue/min) LDL-cholesterol group. L-NMMA significantly reduced (similar to 30%) the vasodilator response to acetylcholine in the optimal/near optimal LDL-cholesterol group but not the borderline high or high LDL-cholesterol groups. Borderline high LDL-cholesterol is associated with impaired nitric oxide-mediated endothelium-dependent vasodilation. Clin Trans Sci 2012; Volume #: 16