Microalbuminuria and plasma aldosterone levels in nondiabetic treatment-naïve patients with hypertension

Effect of Metabolic Adaptation by Voluntary Running Wheel Activity and Aldosterone Inhibition on Renal Function in Female Spontaneously Hypertensive Rats

Metabolic effects of physical activity may be reno-protective in the context of hypertension, although exercise stresses kidneys. Aldosterone participates in renal disease in hypertension, but exercise affects the plasma concentration of aldosterone. This study was designed to evaluate whether physical activity and pharmacological treatment by aldosterone have additive effects on renal protection in hypertensive rats. Female spontaneously hypertensive rats (SHR) or normotensive Wistar rats performed voluntary running wheel activity alone or in combination with aldosterone blockade (spironolactone). The following groups were studied: young and pre-hypertensive SHR (n = 5 sedentary; n = 10 running wheels, mean body weight 129 g), 10-month-old Wistar rats (n = 6 sedentary; n = 6 running wheels, mean body weight 263 g), 10-month-old SHRs (n = 18 sedentary, mean body weight 224 g; n = 6 running wheels, mean body weight 272 g; n = 6 aldosterone, mean body weight 219 g; n = 6 aldosterone and running wheels, mean body weight 265 g). Another group of SHRs had free access to running wheels for 6 months and kept sedentary for the last 3 months (n = 6, mean body weight 240 g). Aldosterone was given for the last 4 months. SHRs from the running groups had free access to running wheels beginning at the age of 6 weeks. Renal function was analyzed by microalbuminuria (Alb/Cre), urinary secretion of kidney injury molecule-1 (uKim-1), and plasma blood urea nitrogen (BUN) concentration. Molecular adaptation of the kidney to hypertension and its modification by spironolactone and/or exercise were analyzed by real-time PCR, immunoblots, and histology. After six months of hypertension, rats had increased Alb/Cre and BUN but normal uKim-1. Voluntary free running activity normalized BUN but not Alb/Cre, whereas spironolactone reduced Alb/Cre but not BUN. Exercise constitutively increased renal expression of proprotein convertase subtilisin/kexin type 9 (PCSK9; mRNA and protein) and arginase-2 (mRNA). Spironolactone reduced these effects. uKim-1 increased in rats performing voluntary running wheel activity exercise irrespectively of blood pressure and aldosterone blockade. We observed independent but no additive effects of aldosterone blockade and physical activity on renal function and on molecules potentially affecting renal lipid metabolism.

The potential role of complement alternative pathway activation in hypertensive renal damage

Hypertensive renal damage is a common secondary kidney disease caused by poor control of blood pressure. Recent evidence has revealed abnormal activation of the complement alternative pathway (AP) in hypertensive patients and animal models and that this phenomenon is related to hypertensive renal damage. Conditions in the setting of hypertension, including high renin concentration, reduced binding of factor H to the glomerular basement membrane, and abnormal local synthesis of complement proteins, potentially promote the AP activation in the kidney. The products of the AP activation promote the phenotypic transition of mesangial cells and tubular cells, attack endothelial cells and recruit immunocytes to worsen hypertensive renal damage. The effects of complement inhibition on hypertensive renal damage are contradictory. Although clinical data support the use of C5 monoclonal antibody in malignant hypertension, pharmacological inhibition in hypertensive animals provides little benefit to kidney function. Therefore, the role of the complement AP in the pathogenesis of hypertensive renal damage and the value of complement inhibition in hypertensive renal damage treatment must be further explored.

Long-term impact of spironolactone compliance on microalbuminuria in patients with primary aldosteronism

Patients with primary aldosteronism (PA) have a high prevalence of microalbuminuria (MAU), which leads to more severe systemic vascular damage. However, the primary recommended drug treatment for PA, spironolactone (SPL), has had poor patient compliance owing to its adverse effects, and the effect of SPL compliance on MAU has not been fully evaluated in patients with PA. We analyzed the effect of SPL compliance on endothelial dysfunction by assessing MAU in patients with PA. The study included 145 confirmed PA patients who received long-term medical treatment (mean, 5 years). As expected, compliance with SPL treatment improved patients' blood pressure and serum potassium levels. Patients with PA who complied fully with SPL treatment had a lower rate of MAU than noncompliant patients (13.73% versus 34.88%, respectively; P = 0.004). Multivariate logistic regression analyses adjusted for age and sex showed that continuous SPL treatment was associated with a lower presence of MAU (odds ratio, 0.319; 95% confidence interval, 0.135-0.750; P = 0.009). This association remained significant after further adjusting for other major risk factors. However, in the subgroup analysis, the protective effect against MAU was limited in compliant patients treated with ≥40 mg/day SPL compared with noncompliant patients (9.62% versus 34.88%, respectively; P < 0.05). Our findings demonstrated that in addition to improving high blood pressure and hypokalemia, full compliance with the appropriate dose of SPL may benefit endothelial function, as reflected by a lower prevalence of MAU in patients with PA.

Primary Aldosteronism: Cardiovascular Risk, Diagnosis, and Management

Primary aldosteronism remains a leading cause of secondary hypertension, and its diagnosis and management continue to pose a challenge for clinicians. In this article, we review the diagnosis of primary aldosteronism along with its cardiovascular manifestations. Treatment is described depending on the diagnostic outcome, focusing on medical management with mineralocorticoid receptor antagonists and unilateral adrenalectomy. Although screening and diagnosing hyperaldosteronism follows well-known algorithms, in practice, physicians may find difficulty establishing the best course of action due to complexity in testing and confirming laterality of aldosterone production by the adrenals. Recognizing and treating primary aldosteronism requires a multidisciplinary approach with primary care physicians, cardiologists, endocrinologists, and radiologists working collaboratively.

Subclinical atherosclerosis due to increase of plasma aldosterone concentrations in essential hypertensive individuals

BACKGROUND AND AIMS

The adrenal mineralocorticoid system plays a key role in cardiovascular, metabolic and renal damage. This study aimed to assess the relationship between plasma aldosterone concentration (PAC) and some surrogate markers of subclinical atherosclerosis, such as carotid intima-media thickness (cIMT), ankle-brachial index (ABI) and biochemical parameters in patients with essential hypertension.

METHODS AND RESULTS

From January 2014 to December 2017, we consecutively enrolled 804 essential hypertensive patients (407 men and 397 women, mean age 50 ± 14 years) without cardiovascular complications, distinguishing patients in quartiles according to PAC. Compared with the first quartile, the highest PAC quartile was associated with the highest levels of serum uric acid (SUA) (5.3 ± 1.3 vs. 5.0 ± 1.0 mg/dl; P = 0.01), triglycerides (117.5 ± 15.7 vs. 106.8 ± 10.5 mg/dl; P < 0.05), 24-h urinary albumin excretion (UAE) (38.8 ±  vs. 7.6 ± mg/24 h; P < 0.05), cIMT (0.87 ± 0.22 vs. 0.80 ± 0.21 mm; P = 0.001) and increased prevalence of carotid plaques (26 vs. 16%; P < 0.005). Moreover, we found that in patients with PAC more than 150 pg/ml, the ABI was significantly lower than those with PAC < 150 pg/ml (1.01 ± 0.09 vs. 1.10 ± 0.09; P < 0.022). PAC was also found to be an independent predictor of the presence of carotid plaques and pathological ABI (<0.9) in essential hypertensive individuals.

CONCLUSION

Our results revealed that higher PAC values are strongly associated with some metabolic variables, as triglycerides, UAE, cIMT, worse ABI and major prevalence of carotid plaques that, together with elevated blood pressure values, are strictly correlated with higher risk of atherosclerosis and cardiovascular complications.