Serum γ-Glutamyltransferase Concentration Predicts Endothelial Dysfunction in Naïve Hypertensive Patients

Background: Serum gamma-glutamyltransferase (γ-GT) is recognized as a risk factor for cardiovascular diseases (CV). Traditional cardiovascular risk factors mediate endothelial dysfunction. Aim: to evaluate a possible correlation between serum-GT and endothelium-dependent vasodilation in naive hypertensives. Methods: We enrolled 500 hypertensives. Endothelial function was studied by strain-gauge plethysmography. Receiver operating characteristic (ROC) analysis was used to assess the predictive value of γ-GT and to identify the optimal cut-off value of the same variable for endothelial dysfunction. Results: At univariate linear analysis peak percent increase in acetylcholine (ACh)-stimulated vasodilation was inversely related to γ-GT (r =-0.587), alanine aminotransferase (ALT) (r =-0.559), aspartate aminotransferase (AST) (r =-0.464), age (r =-0.171), body mass index (BMI) (r =-0.152), and fasting glucose (r =-101). In the stepwise multivariate regression model, endothelium-dependent vasodilation was significantly related to γ-GT (β =-0.362), ALT (β =-0.297), AST (β =-0.217), estimated glomerular filtration rate (e-GFR) (β = 0.199), gender (β = 0.166), and smoking (β =-0.061). The ROC analysis demonstrated that the accuracy of γ-GT for identifying patients with endothelial dysfunction was 82.1%; the optimal γ-GT cut-off value for discriminating patients with this alteration was 27 UI/L. Conclusions: Serum γ-GT values, within the normal range, are significantly associated with endothelial dysfunction in hypertensives, and may be considered a biomarker of early vascular damage.