Effect Of Acute Hyperglycemia On Endothelial Function In Normal And Overweight Children

Abstract

Acute hyperglycemia in middle-and older-aged adults has been reported to induce transient endothelial dysfunction. To date, effect of acute hyperglycemia on endothelial function in children has not been examined. PURPOSE The purpose of this study was to investigate the impact of acute hyperglycemia on endothelial function in both normal weight and overweight children. METHODS Fifteen overweight (BMI ≥ 85th percentile) and 10 normal weight children (BMI<85th percentile) were evaluated for brachial artery flow-mediated dilation (FMD), fasting glucose and insulin at baseline and 30, 60, and 120 minutes after glucose ingestion. Fifteen minutes following the measurement of FMD, 0.3 mg sublingual nitroglycerin (NTG) was administered and after 3 min the brachial artery was imaged in order to assess endothelium-independent dilation. RESULTS There were no statistically significant differences in gender, Tanner score or age between the normal weight and overweight children. By design the overweight children were significantly heavier (63.2 ± 4.9 vs. 43.5 ± 3.5 kg, p=0.0074) and had a greater percent body fat (43.9 ± 1.9 vs. 26.0 ± 2.5%, p<0.0001). There were no significant differences in fasting plasma glucose (85.5 ± 1.3 vs. 86.2 ± 1.2 mg/dL, P=0.699) or insulin (6.0 ± 0.8 vs. 9.0 ± 1.3 uU/mL, P=0.096) levels between the normal weight and overweight groups. The area under the curve in response to oral glucose administration was significantly (p<0.0001) greater in the overweight group for both glucose and insulin (p<0.0001). FMD area under the curve was not significantly (P=0.2986) different at rest (P=0.24) or between time points after oral glucose ingestion nor was there a difference in response between the two groups. The FMD response NTG was significantly greater in the normal weight compared to the overweight group (26.7 ± 2.4 vs. 20.0 ± 2.2%, P=0.055). CONCLUSION Despite significant increases in glucose and insulin concentrations in both overweight and normal weight children during an acute oral glucose challenge there was no change in vascular function in either group. These data suggest that acute elevations of glucose and insulin in overweight and normal weight children are not associated with acute impairment in endothelial function.