Gafane-Matemane Lebo F, van Rooyen Johannes M, Schutte Rudolph, Schutte Aletta E
Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, South Africa; Research Unit for Hypertension and Cardiovascular Disease, Medical Research Council, North-West University, Potchefstroom, South Africa.
Hypertension in Africa Research Team (HART), North-West University, Potchefstroom, South Africa; Department of Medicine and Healthcare Science, Faculty of Medical Science, Anglia Ruskin University, Chelmsford, United Kingdom.
Cardiovasc J Afr. 2019;30(1):34-40. doi: 10.5830/CVJA-2018-065. Epub 2019 Jan 22.
Hypertension, particularly in black populations, is often accompanied by augmented sympathetic nervous system activity and suppressed renin activity, indicative of possible blood pressure (BP) dysregulation. The potential role of the interrelationship between the renin-angiotensin-aldosterone system (RAAS) and the sympathetic nervous system in the context of low-renin conditions is unclear. We therefore explored whether surrogate measures of sympathetic activity [noradrenaline, 24-hour heart rate (HR) and percentage (%) dipping of night-time HR] relate to renin, aldosterone and aldosterone-to-renin ratio (ARR) in black and white South Africans.
We included black (n = 127) and white (n = 179) males and females aged 20-63 years. We measured 24-hour BP and HR, and calculated night-time dipping. We determined renin and aldosterone levels in plasma and calculated ARR. Noradrenaline and creatinine levels were determined in urine and the noradrenaline:creatinine ratio was calculated.
More blacks had low renin levels (80.3%) compared to whites (58.7%) (p < 0.001). In univariate and after multivariate analyses the following significant associations were evident in only the black group: HR dipping was associated negatively with aldosterone level (β = -0.18, p = 0.024) and ARR (β = -0.20, p = 0.011), while 24-hour HR was associated positively with renin level (β = 0.20, p = 0.024). Additionally, there was a borderline significant positive association between noradrenaline:creatinine ratio and aldosterone level (β = 0.19, p = 0.051).
The observed associations between surrogate measures of sympathetic nervous system activity and components of the RAAS in the black group suggest that the adverse effects of aldosterone and its ratio to renin on the cardiovascular system may be coupled to the effects of the sympathetic nervous system.
高血压，尤其是在黑人人群中，常伴有交感神经系统活动增强和肾素活性受抑制，这表明可能存在血压调节异常。在低肾素状态下，肾素 - 血管紧张素 - 醛固酮系统（RAAS）与交感神经系统之间相互关系的潜在作用尚不清楚。因此，我们探讨了交感神经活动的替代指标[去甲肾上腺素、24小时心率（HR）和夜间HR的下降百分比（%）]与南非黑人和白人的肾素、醛固酮及醛固酮与肾素比值（ARR）之间的关系。
我们纳入了年龄在20 - 63岁的黑人（n = 127）和白人（n = 179）男性和女性。我们测量了24小时血压和心率，并计算夜间下降情况。我们测定了血浆中的肾素和醛固酮水平，并计算ARR。测定了尿液中的去甲肾上腺素和肌酐水平，并计算去甲肾上腺素与肌酐比值。
与白人（58.7%）相比，更多黑人肾素水平较低（80.3%）（p < 0.001）。在单变量分析及多变量分析后，仅在黑人组中出现了以下显著关联：HR下降与醛固酮水平呈负相关（β = -0.18，p = 0.024）和与ARR呈负相关（β = -0.20，p = 0.011），而24小时HR与肾素水平呈正相关（β = 0.20，p = 0.024）。此外，去甲肾上腺素与肌酐比值和醛固酮水平之间存在边缘显著的正相关（β = 0.19，p = 0.051）。
在黑人组中观察到的交感神经系统活动替代指标与RAAS各成分之间的关联表明，醛固酮及其与肾素的比值对心血管系统的不良影响可能与交感神经系统的作用相关。
