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Objective: Nitroglycerine-induced vasodilation has been used as a control test for flow-mediated vasodilation (FMD) to differentiate endothelium-dependent from endothelium-independent response when evaluating endothelial function in humans. Recently, nitroglycerine-induced vasodilation has also been reported to be impaired in patients with atherosclerosis. The purpose of this study was to determine the relationships between nitroglycerine-induced vasodilation and cardiovascular risk factors., Approach and Results: We measured nitroglycerine-induced vasodilation and FMD in 436 subjects who underwent health examinations (mean age, 53 ± 19 years; age range, 19-86 years), including patients with cardiovascular diseases. There was a significant relationship between nitroglycerine-induced vasodilation and FMD (r=0.42; P<0.001). Univariate regression analysis revealed that nitroglycerine-induced vasodilation correlated with age (r=-0.34; P<0.001), systolic blood pressure (r=-0.32; P<0.001), diastolic blood pressure (r=-0.24; P<0.001), heart rate (r=-0.21; P<0.001), glucose (r=-0.23; P<0.001), and smoking pack-year (r=-0.12; P=0.01), as well as Framingham risk score (r=-0.30; P<0.001). Nitroglycerine-induced vasodilation was significantly smaller in patients with cardiovascular disease than in both subjects with and without cardiovascular risk factors (10.5 ± 5.6% versus 13.7 ± 5.4% and 15.3 ± 4.3%; P<0.001, respectively), whereas there was no significant difference in nitroglycerine-induced vasodilation between subjects with and without cardiovascular risk factors. Multivariate analysis revealed that male sex, body mass index, hypertension, diabetes mellitus, baseline brachial artery diameter, and FMD were independent predictors of nitroglycerine-induced vasodilation., Conclusions: These findings suggest that nitroglycerine-induced vasodilation may be a marker of the grade of atherosclerosis. FMD should be interpreted as an index of vascular function reflecting both endothelium-dependent vasodilation and endothelium-independent vasodilation in subjects with impaired nitroglycerine-induced vasodilation.

Objective: Cardiovascular diseases are associated with impaired flow-mediated vasodilation (FMD) and increase in carotid intima-media thickness (IMT). Both FMD and IMT are independent predictors for cardiovascular outcomes. When measuring FMD and nitroglycerine-induced vasodilation in the brachial artery, IMT can also be simultaneously assessed in the same brachial artery. The purpose of this study was to determine the relationships between IMT of the brachial artery, vascular function, and cardiovascular risk factors., Methods and Results: We measured brachial IMT, FMD, and nitroglycerine-induced vasodilation by ultrasound in 388 subjects who underwent health examination (mean age, 45±22 years; age range, 19-86), including patients with cardiovascular diseases. Univariate regression analysis revealed that brachial IMT significantly correlated with age (r=0.71; P<0.001), body mass index (r=0.27; P<0.001), systolic blood pressure (r=0.40; P<0.001), diastolic blood pressure (r=0.31; P<0.001), heart rate (r=0.15; P=0.002), glucose level (r=0.18; P=0.01), and smoking pack-years (r=0.42; P<0.001), as well as Framingham risk score, a cumulative cardiovascular risk index for heart attack (r=0.49; P<0.001). FMD and nitroglycerine-induced vasodilation were inversely associated with brachial IMT (r=-0.39, P<0.001; r=-0.32, P<0.001, respectively). In addition, there was a significant relationship between brachial IMT and carotid IMT (r=0.58; P<0.001). Multivariate analysis revealed that age, sex, hypertension, and brachial artery diameter were independent predictors of brachial IMT., Conclusions: These findings suggest that brachial IMT may be a marker of the grade of atherosclerosis and may be used as a marker of vascular function, providing additive information for stratifying subjects with cardiovascular risk factors.

Objective: Geranylgeranylacetone (GGA) induces expression of heat shock protein 90 (Hsp90), an adaptor molecule for assembly of endothelial nitric oxide synthase (eNOS) phosphorylation complex. The purpose of this study was to determine whether GGA enhances Hsp90 expression and augments endothelium-dependent vasodilation via upregulation of eNOS in humans., Methods and Results: We evaluated the effects of GGA on human umbilical vein endothelial cells (HUVECs) and on forearm blood flow (FBF) responses to acetylcholine and sodium nitroprusside in 40 healthy young men. Hsp90, eNOS, AMP-activated protein kinase (AMPK), and Akt expression in HUVECs and peripheral blood mononuclear cells was detected by Western blot analysis. GGA increased Hsp90 expression and phosphorylation of eNOS and AMPK but not Akt in HUVECs and increased Hsp90 expression in peripheral blood mononuclear cells. Oral administration of GGA (600 mg) augmented the FBF response to acetylcholine. Infusion of N(G)-monomethyl-l-arginine, an NO synthase inhibitor, completely abolished GGA-induced augmentation of the FBF response to acetylcholine. GGA also augmented the acetylcholine-stimulated NO release in smokers., Conclusions: These findings suggest that GGA-induced activation of Hsp90/AMPK significantly increased NO-mediated vasodilation in healthy subjects, as well as in smokers. The use of GGA may be a new therapeutic approach for improving endothelial dysfunction.

Objective: Cardiovascular diseases are associated with chronic activation of Rho-associated kinases (ROCKs) and endothelial dysfunction. Both increased ROCK activity and endothelial dysfunction are thought to be closely associated with conventional cardiovascular risk factors. The purpose of this study was to determine the relationships between ROCK activity, endothelial function, and cardiovascular risk factors., Methods and Results: We evaluated ROCK activity in peripheral leukocytes by Western blot analysis and flow-mediated vasodilation by ultrasonography in 242 men who had no cardiovascular or cerebrovascular diseases (mean age, 40±10 years; range, 20 to 73 years). ROCK activity was defined as the ratio of phospho myosin-binding subunit on myosin light chain phosphatase to total myosin-binding subunit. Univariate regression analysis revealed that leukocyte ROCK activity significantly correlated with body mass index (r=0.29, P=0.003); systolic blood pressure (r=0.25, P=0.01); low-density lipoprotein cholesterol level (r=0.21, P=0.04); and Framingham risk factor score, a cumulative cardiovascular risk index for heart attack (r=0.31, P<0.001), and that flow-mediated vasodilation significantly correlated with age (r=-0.23, P=0.02), body mass index (r=0.19, P=0.05), systolic blood pressure (r=-0.22, P=0.03), total cholesterol level (r=-0.21, P=0.04), low-density lipoprotein cholesterol level (r=-0.22, P=0.04), glucose level (r=-0.20, P=0.04), and Framingham risk factor score (r=-0.37, P<0.001). There was a significant correlation between leukocyte ROCK activity and flow-mediated vasodilation (r=-0.41, P<0.001). Multivariate analysis revealed that flow-mediated vasodilation was an independent predictor of leukocyte ROCK activity., Conclusions: These findings suggest that cumulative cardiovascular risk may enhance ROCK activity and endothelial dysfunction, leading to progression of cardiovascular diseases and outcomes.