Vasoactive mediators of hypertension in obesity.

Obesity is associated with hypertension. However, the mechanisms involved are not fully understood. Therefore, we investigated the relationship between obesity and vasoactive mediators. In this cross-sectional study, blood pressure (BP) and vasoactive mediators of hypertension are compared among 135 adults in the nonobese, obese, and morbidly obese body mass index (BMI) ranges (BMI ≤27, 30-40, and >40 kg/m, respectively). Angiotensinogen, angiotensin II, renin, aldosterone, endothelin-1 (ET-1), neprilysin, atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), cyclic guanosine monophosphate (cGMP), and cyclic adenosine monophosphate (cAMP) levels were measured and their relationship to BP, BMI, race, and gender were investigated. Systolic and diastolic BP (SBP and DSP) were significantly higher in subjects with obesity and morbid obesity compared with nonobese. Angiotensin II, ET-1, and neprilysin were significantly higher in subjects with morbid obesity while BNP was lower. Levels of angiotensinogen, renin, aldosterone, ANP, cGMP, and cAMP did not differ between the groups. BMI was positively related to SBP, DBP, angiotensin II, ET-1, and neprilysin, and inversely related to cGMP and BNP. Age, male gender, and African-American race were associated with higher SBP. SBP was positively related to angiotensin II and ET-1 and inversely related to aldosterone, renin, and cGMP. On multivariate analyses, age, BMI, gender, and race were the main determinants of SBP, and excluding these variables, angiotensin II, aldosterone, renin, and ET-1 accounted for 21.1% ability to predict SBP. Obesity, especially morbid obesity, is associated with higher BP, higher angiotensin II and ET-1 (vasoconstrictors), and lower levels BNP and cGMP (vasodilators). SBP variability can be partly explained by angiotensin II, aldosterone, renin, and ET-1. Our data show that obesity, especially morbid obesity, is associated with higher blood pressure levels and increases angiotensin II and endotherlin-1 (ET-1) (vasoconstrictors) and lower levels BNP and cGMP (vasodilators) and that systolic blood pressure variability can be partly explained by levels of angiotensin II, aldosterone, renin, and ET-1. The effect of these mediators on blood pressure is in addition to the effects of other known factors related to age, male gender, and AA race.