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

Abstract  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 (43–64 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 N G ‐monomethyl‐L‐arginine (L‐NMMA). Vasodilation to acetylcholine was ∼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 (∼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 #: 1–6