Adiposity has unique influence on the renin-aldosterone axis and blood pressure in black children.

To comparatively examine the effects of adiposity on the levels of plasma renin activity (PRA), plasma aldosterone concentration (PAC), and aldosterone-renin ratio (ARR) in young black and white children. We prospectively assessed 248 black and 345 white children and adolescents. A novel analytical technique was used to assess the concurrent influences of age and body mass index (BMI) on PRA, PAC, and ARR. The estimated effects were depicted by colored contour plots. In contrast to whites, blacks had lower PRA (2.76 vs 3.36 ng/mL/h; P < .001) and lower PAC (9.01 vs 14.59 ng/dL; P < .001). In blacks, BMI was negatively associated with PRA (P = .001), consistent with an association with a more expanded plasma volume; there was no association with PAC. In whites, BMI was positively associated with PAC (P = .005); we did not detect a BMI-PRA association. The effects of BMI on ARR were directionally similar in the two race groups but more pronounced in blacks. Mean systolic blood pressure was greater in blacks with lower PRA (P < .01), higher PAC (P = .015), and higher ARR (P = .49). An increase in adiposity was associated with a suppressed PRA in blacks and an increase in PAC in whites. The unique relationship between adiposity and renin-aldosterone axis in blacks suggests the possible existence of a population-specific mechanism characterized by volume expansion, which could in turn enhance the influences of adiposity on blood pressure in black children and adolescents.

Yu Z ，Eckert GJ ，Liu H ，Pratt JH ，Tu W ... -  《-》

Varying Influences of Aldosterone on the Plasma Potassium Concentration in Blacks and Whites.

Aldosterone acts to restrain the extracellular potassium (K+) concentration. Blacks have on average lower plasma aldosterone concentrations (PACs) than Whites. Whether this ethnic difference is associated with similar changes in the concentration of K+ is unclear. Subjects were Blacks and Whites from an observational study of blood pressure regulation. PAC was known to be significantly lower in Blacks than Whites. We sought to test the hypothesis that the concentration of K+ remains constant despite variability in PAC. Initial enrollment took place in childhood in 1986. Some of the original enrollees were studied again in adulthood: 160 healthy Blacks and 271 healthy Whites (ages 5 to 39 years; all were studied as children and as adults). Plasma renin activity [a biomarker of angiotensin II and, more proximally, extracellular fluid volume (ECFV)] and PAC were lower in Blacks (P < 0.0354 and P < 0.001, respectively, for all ages). At the same time no ethnic difference in levels of K+ was observed regardless of age. Plasma K+ concentration and PAC associated differently based on ethnicity: PAC increased in Blacks by 1.5-2.0 and in Whites by 2.3-3.0 ng/dl per mmol/l increase in K+ (P < 0.001). Lower aldosterone levels in Blacks did not translate into higher K+ concentrations. We speculate that reaching the right concentration of K+ was an endpoint of aldosterone production in the presence of varying levels of ECFV and angiotensin II.

Tu W ，Eckert GJ ，Decker BS ，Howard Pratt J ... -  《-》

Association of renin and aldosterone with ethnicity and blood pressure: the Multi-Ethnic Study of Atherosclerosis.

Rifkin DE ，Khaki AR ，Jenny NS ，McClelland RL ，Budoff M ，Watson K ，Ix JH ，Allison MA ... -  《-》

Plasma levels of prorenin and renin in blacks and whites: their relative abundance and associations with plasma aldosterone concentration.

Tu W ，Eckert GJ ，Pratt JH ，Jan Danser AH ... -  《-》

Plasma renin activity and aldosterone concentrations in hypertensive cats with and without azotemia and in response to treatment with amlodipine besylate.

Role of renin-angiotensin aldosterone system (RAAS) in feline systemic hypertension is poorly understood. Examine plasma renin activity (PRA) and plasma aldosterone concentrations (PAC) in normotensive and hypertensive cats with variable renal function and in response to antihypertensive therapy. One hundred and ninety-six cats >9 years from first opinion practice. PRA, PAC, and aldosterone-to-renin ratio (ARR) were evaluated in cats recruited prospectively and grouped according to systolic blood pressure (SBP) and renal function (nonazotemic normotensive [Non-Azo-NT], nonazotemic hypertensive [Non-Azo-HT], azotemic normotensive [Azo-NT], azotemic hypertensive [Azo-HT]). Changes in PRA and PAC were evaluated with antihypertensive therapy (amlodipine besylate). Plasma renin activity (ng/mL/h; P = .0013), PAC (pg/mL; P < .001), and ARR (P = 0.0062) differed significantly among groups. PRA (ng/mL/h) was significantly lower in hypertensive (Non-Azo-HT; n = 25, median 0.22 [25th percentile 0.09, 75th percentile 0.39], Azo-HT; n = 44, 0.33 [0.15, 0.48]) compared with Non-Azo-NT cats (n = 57, 0.52 [0.28, 1.02]). Azo-HT cats had significantly higher PAC (n = 22, 149.8 [103.1, 228.7]) than normotensive cats (Non-Azo-NT; n = 26, 45.4 [19.6, 65.0], Azo-NT; n = 18, 84.1 [38.6, 137.8]). ARR was significantly higher in Azo-HT (n = 20, 503.8 [298.8, 1511]) than Azo-NT cats (n = 16, 97.8 [77.0, 496.4]). Significant increase in PRA was documented with antihypertensive therapy (pretreatment [n = 20] 0.32 [0.15-0.46], posttreatment 0.54 [0.28, 1.51]), but PAC did not change. Hypertensive cats demonstrate significantly increased PAC with decreased PRA. PRA significantly increases with antihypertensive therapy. Additional work is required to determine the role of plasma aldosterone concentration in the pathogenesis of hypertension and whether this relates to autonomous production or activation of RAAS without demonstrable increase in PRA.

Jepson RE ，Syme HM ，Elliott J 《-》