Plasma renin and cardiovascular responses to the cold pressor test differ in black and white populations: The SABPA study

Abstract

Low plasma renin levels and augmented cardiovascular reactivity to stress are common in blacks and have been linked to the development of hypertension in this population. We (i) compared cardiovascular and plasma renin reactivity to a cold pressor test between a black and white population; and (ii) investigated the associations between cardiovascular and plasma renin reactivity within the black and white populations. Our population consisted of 153 black and 188 white men and women (age range, 20-65 years). We measured blood pressure (BP), heart rate (HR), stroke volume (SV), total peripheral resistance (TPR), Windkessel arterial compliance, and determined plasma renin levels at rest and during the cold pressor test. Reactivity was calculated for each participant as the percentage change from the resting value. We found lower renin and elevated BP in blacks compared with whites at rest and during stress (both, P<0.001). During stress, HR increased more in blacks (P<0.001), whereas SV (P<0.001) and arterial compliance (P=0.013) decreased more in blacks compared with whites. TPR reactivity was positively associated with renin reactivity in blacks only (β=0.17; P=0.041), while in whites diastolic BP reactivity was positively associated with renin reactivity (β=0.21; P=0.005). Although blacks had suppressed renin levels at rest and during acute stress, vascular resistance reactivity associated positively with renin reactivity only in the black population. These results suggest that low renin levels in blacks during rest and stress are linked to increased peripheral vascular responses to stress, which may contribute to elevated BP in blacks.

Marinobufagenin is related to elevated central and 24-h systolic blood pressures in young black women: the African-PREDICT Study

“…We have recently published a detailed review on the advances in understanding the distinct physiological, lifestyle and demographic differences between black and white populations, including dietary, cultural and physiological differences [21] (e.g., suppressed renin [22], increased arterial stiffness [23–25], sympathetic nerve activity [26, 27] and an increased inflammatory profile [28, 29] in black populations). Thus, the results from the present study reflect one aspect of an entire array of factors collectively contributing to an adverse cardiovascular pro-file, specifically observed in the black women of this study, and should therefore be interpreted accordingly.…”

Genetics of Hypertension in African Americans and Others of African Descent

“…One study demonstrated lower levels of plasma renin activity and aldosterone in normotensive African Americans across all ages, with BP positively correlating with plasma aldosterone, an effect that increased as plasma renin activity decreased [48]. Thus, a typical biochemical profile in an African American person with hypertension is a low or high plasma aldosterone concentration, a low or suppressed plasma renin activity or direct renin concentration, and suppressed angiotensin I and II [36,50,54,55]. This results in a normal or elevated aldosterone-to-renin ratio, which can be categorized into two broad hypertension phenotypes: low or suppressed renin and elevated aldosterone (primary aldosteronism type, or hyporeninemic hyperaldosteronism) and low renin and low aldosterone (Liddle syndrome type, or hyporeninemic hypoaldosteronism) [56].…”

Distinct inflammatory mediator patterns in young black and white adults: The African-predict study

“…18,19 Many mechanisms have been proposed to explain this, such as a suppressed renin-angiotensin-aldosterone-system and salt sensitivity in black populations. [20][21][22] Based on our previous work in South Africa, 23,24 another possible mechanism could be related to inflammation. Differences in pro-and anti-inflammatory mediator concentrations between ethnic groups have indeed been reported, e.g.…”