The Ucp2 Insertion/Deletion Gene Polymorphism Contributes To Elevated Blood Pressure Via An Interaction Between Obesity And Nitric Oxide

PURPOSE The purpose of the study was to compare body fatness, cardio-respiratory fitness, blood pressure, and nitric oxide across the UCP2 gene I/D polymorphism. METHODS Apparently healthy volunteers (non-obese of 54 & obese of 39) aged between 20–30 yrs old were recruited via flyers and local advertisements. Body fatness measures included body weight, percent body fat, waist circumference, and waist-to-hip (WHR) ratio. Cardio-respiratory fitness measures included VO2max, 1-min recovery heart rate, and treadmill exercise duration. Diastolic and systolic blood pressures were measured by using a mercury sphygmometer and mean arterial blood pressure was calculated. Nitrate activity was measured in fasting plasma samples. RESULTS Chi-square analysis showed no significant difference in the relative frequencies of the UCP2 I/D genotypes between the non-obese and obese groups. One-way analyses of variance showed that there were significant genotype differences in DBP (p=0.029), MAP (p=0.040), and nitrate concentration (p=0.027) in the obese group such that those with DD genotype had significantly higher values than those with ID genotype. With respect to the non-obese group, however, there were no significant genotype differences in any of the measured variables. CONCLUSIONS Therefore, the current findings suggest that 1) the UCP2 I/D gene polymorphism may contribute to elevated blood pressure in the obese group and 2) higher nitrate concentration in those with DD genotype than in those with ID genotype may reflect a compensatory response to the elevated blood pressure in the obese group. Supported by the Korean Research Foundation (2003–041-G00128) and Sungkyunkwan University Faculty Research Foundation