Metabolic Syndrome and Endothelin‐1 mediated vasoconstrictor tone in overweight/obese adults

Abstract

Overweight/obesity (OW/OB) is associated with profound endothelial vasomotor dysfunction. Indeed, endothelin (ET)‐1‐mediated vasoconstrictor tone is markedly elevated with OW/OB and contributes mechanistically to both impaired vasodilator function and increased cardiovascular risk. Metabolic syndrome (MetS) often accompanies OW/OB with unfavorable vascular consequences. We tested the hypothesis that ET‐1 vasoconstrictor tone is greater in OW/OB adults with the MetS compared with OW/OB without MetS. Forearm blood flow (FBF; plethysmography) responses to selective ETA receptor blockade (BQ‐123; 100 nmol/min; for 60 min) and ETA/B receptor blockade (BQ‐123 + BQ‐788 [50nmol/min for 60 min]) were determined in 24 OW/OB adults: 12 without MetS (8M/7F; BMI: 28.1±1.0 kg.m−2) and 12 with MetS (8/4; BMI: 29.4±0.8 kg.m−2). MetS was established according to NCEP ATP III guidelines. BQ‐123 elicited a significantly greater increase (~90%) in FBF in OW/OB adults with the MetS than in OW/OB adults without MetS. The co‐infusion of BQ‐123 and BQ‐788 significantly increased the FBF in both groups, but there are no differences in responses between the groups. FBF to BQ‐123 after 60 min was associated with plasma triglyceride concentrations (r=0.56; P<0.05) in OW/OB adults with the MetS. In conclusion, MetS appears to adversely affect ETA, but not ETB, receptor mediated vasoconstrictor tone in OW/OB adults.