Recent epidemiologic and experimental evidence suggests that serum uric acid (UA) is an independent risk factor for cardiovascular and renal diseases. However, endothelial dysfunction is an early predictor of cardiovascular events, particularly in hypertensive patients. For assessment of the association between UA and endothelial function, 217 (108 men, 109 women; aged 48.0 ± 10.6 yr) white never-treated hypertensive patients were studied. All patients underwent the following procedures: BP measurements, laboratory tests (C-reactive protein [CRP], insulin resistance by homeostasis model assessment, serum creatinine, and UA), and endothelial function evaluated by intra-arterial infusion of acetylcholine (ACh). Serum creatinine, CRP, and maximal vasodilatory response to ACh were related to the UA (all P < 0.0001). In the multiple regression analysis, serum UA ranked as the third correlate of peak of forearm blood flow predictor, after homeostasis model assessment and CRP. The data show an independent link between UA and endothelial function, also in a statistical model that included CRP. In conclusion, the data demonstrate an inverse and significant relationship between UA and ACh-stimulated vasodilation in patients with uncomplicated, untreated essential hypertension, independent of traditional cardiovascular risk factors. Probably, the chronic inflammation that was documented in these patients may be considered the mechanistic link between serum UA and vascular damage.

OBJECTIVE—We studied the relationships between plasma IGF-I concentrations and insulin sensitivity in subjects with various degrees of glucose tolerance. RESEARCH DESIGN AND METHODS—A total of 357 nondiabetic subjects, 54 subjects with impaired glucose tolerance and 98 newly diagnosed type 2 diabetic subjects, were consecutively recruited, and anthropometric and biochemical characteristics were collected. RESULTS—IGF-I concentrations were negatively correlated with age, BMI, waist-to-hip ratio, triglyceride levels, and systolic and diastolic blood pressure. IGF-I concentrations were positively correlated with HDL cholesterol and homeostasis model assessment of insulin sensitivity (HOMA-S). The correlations remained significant after adjusting for sex, age, and BMI. Correlations for HOMA-S with these metabolic and anthropometric variables were of a similar degree and direction to those for IGF-I concentrations. Stepwise linear regression analysis in a model, which included well-known modulators of insulin sensitivity such as sex, age, BMI, glucose tolerance status, family history of diabetes, waist-to-hip ratio, systolic and diastolic blood pressure, HDL cholesterol, and triglyceride levels, revealed that IGF-I concentrations were independently associated with insulin sensitivity accounting for 10.8% of its variation (P < 0.0001). IGF-I concentrations were significantly lower in subjects with World Health Organization (WHO)-defined metabolic syndrome compared with subjects without metabolic syndrome (P < 0.0001). Logistic regression analysis showed that each unit increase in log-transformed IGF-I concentrations was associated with a 90.5% reduction in the risk of WHO-defined metabolic syndrome. CONCLUSIONS—These data indicate that IGF-I has the characteristics to be a marker for the insulin resistance syndrome. This suggests that low IGF-I levels may be a useful marker for identifying subjects at risk for cardiovascular disease.

Background— Chronic kidney disease is a risk factor for cardiovascular disease, increasing all-cause mortality. Some evidence suggests that endothelial dysfunction is present in the early stages of renal insufficiency, but no data exist about its possible role in the progression of renal disease. Thus, we prospectively evaluated the effect of endothelial function on estimated glomerular filtration rate (eGFR) in essential hypertension. Methods and Results— We enrolled 500 never-treated uncomplicated hypertensive subjects with serum creatinine ≤1.5 mg/dL. Endothelial function was measured by strain-gauge plethysmography during intra-arterial infusion of acetylcholine and sodium nitroprusside. eGFR was calculated by use of the Chronic Kidney Disease Epidemiology Collaboration equation. The annual rate of decline of eGFR (ΔeGFR/y) was determined as the difference between the follow-up and baseline eGFR values, with this value divided by the time interval in years. During follow-up (92.3±36.2 months), mean ΔeGFR/y was 1.49±1.65 mL · min ⁻¹ · 1.73 m ^{− 2} , with no significant differences between men and women (1.55±1.72 versus 1.43±1.58 mL · min ⁻¹ · 1.73 m ^{− 2} , respectively; P =0.455). This was correlated with acetylcholine-stimulated forearm blood flow ( r =−0.256, P <0.0001), creatinine ( r =0.141, P =0.001), systolic blood pressure ( r =−0.103, P =0.01), and eGFR ( r =0.092, P =0.020). In multivariable regression analysis, forearm blood flow and systolic blood pressure remained associated with change in eGFR. On average, eGFR changed by 0.37 mL · min ⁻¹ · 1.73 m ^{− 2} for each 100% change in forearm blood flow ( P <0.001) and by 0.1 mL · min ⁻¹ · 1.73 m ^{− 2} for each difference of 10 mm Hg in systolic blood pressure ( P =0.032). Conclusions— We demonstrated that acetylcholine-stimulated vasodilation and systolic blood pressure were associated with eGFR loss after adjustment for other cardiovascular risk factors and antihypertensive treatment.

Background— Mild to moderate renal insufficiency in individuals with essential hypertension is currently considered the expression of a renal microvasculopathy characterized by preglomerular arteriolar involvement and tubulo-interstitial changes. Whether endothelial dysfunction plays a role in this alteration is still undefined. Methods and Results— We investigated the relationship between endothelial function (hemodynamic response to acetylcholine [ACh] in the forearm) and renal function in 500 patients with uncomplicated, never-treated, essential hypertension and serum creatinine within the normal range (ie, ≤1.5 mg/dL). Serum creatinine, creatinine clearance, and estimated glomerular filtration rate (GFR, by the Modification of Diet in Renal Disease formula) were related to the forearm blood flow response to ACh (all P ≤0.003), and these relationships held true in multiple regression analyses that included age, gender, systolic pressure, serum cholesterol and glucose, smoking, and body mass index. Accordingly, on multiple logistic regression analysis, the risk of moderate renal dysfunction (ie, an estimated GFR <60 mL · min ⁻¹ · 1.73 m ⁻² ) was 64% lower (OR 0.36, 95% CI 0.18 to 0.70) in patients in the third ACh tertile (ie, those showing the higher vasodilatory response) than in those in the first tertile (ie, showing the lower response). C-reactive protein was related directly to serum creatinine and inversely to GFR and vasodilatory response to ACh, which suggests that endothelial dysfunction is a possible mechanism linking inflammation and impaired renal function in essential hypertension. Conclusions— An impaired vasodilatory response to ACh appears to be associated with renal function loss in patients with essential hypertension. This association suggests that systemic endothelial dysfunction is involved in mild to moderate renal insufficiency in patients with uncomplicated essential hypertension.