The renin angiotensin aldosterone system

In this review, we will cover (i) the proteolytic cascade of the RAAS, (ii) its regulation by multiple feedback-controlled parameters, and (iii) the major effects of the RAAS. For the effects of the RAAS, we focus on the role of the RAAS in the regulation of volume homeostasis and vascular tone, as major determinants of arterial blood pressure.

Safety and efficacy of once-daily dexfadrostat phosphate in patients with primary aldosteronism: a randomised, parallel group, multicentre, phase 2 trial

Background

Primary aldosteronism (PA) is caused by autonomous aldosterone overproduction and characterised by uncontrolled hypertension. There are currently no treatments that target aldosterone synthesis. We evaluated the safety and efficacy of a novel aldosterone synthase inhibitor, dexfadrostat phosphate, in patients with PA.

Methods

This multi-centre, randomised, phase 2 trial was conducted between November 2019 and May 2022 (NCT04007406; EudraCT code 2019-000919-85). Adults with PA and an office systolic blood pressure of 145-190 mmHg were included. After a 2-week single-blind placebo run-in period, participants were randomised 1:1:1 to receive oral dexfadrostat phosphate 4, 8, or 12 mg once daily for an 8-week double-blind treatment period, followed by a 2-week single-blind placebo withdrawal period. Randomisation was conducted centrally and stratified by centre and sex. At the beginning and end of the treatment period, 24 h ambulatory systolic blood pressure (aSBP) was recorded. Blood samples were taken every 2 weeks. Primary endpoints were the change in aldosterone-to-renin ratio (ARR) and mean 24 h aSBP from baseline to the end of the treatment period in the combined dose group of all participants receiving any dose of dexfadrostat phosphate. Safety endpoints were the occurrence of treatment-emergent adverse events (TEAEs) and serious adverse events over the entire study in all randomised participants who received at least one dose of dexfadrostat phosphate.

Findings

In total, 35 participants received dexfadrostat phosphate and all participants completed the study. Twenty-six participants (74.3%) were male, the mean age was 51.9 years (SD 8.7), and most were White (n = 32, 91.4%). The median ARR and the mean 24 h aSBP significantly decreased from the beginning to the end of the treatment period in the combined dose group (ARR: 15.3 vs 0.6, least-squares mean [LSM] change in log-normal values -2.5, p < 0.0001; aSBP: 142.6 vs 131.9 mmHg, LSM change -10.7 mmHg, p < 0.0001). There were no safety concerns; all TEAEs were mild or moderate and there were no serious TEAEs.

Interpretation

Dexfadrostat phosphate corrected the ARR and aSBP and was well tolerated in patients with PA, demonstrating the benefit of pharmacologically targeting the source of hyperaldosteronism.

Funding

DAMIAN Pharma AG.

Case-inspired exploration of renin mutations in autosomal dominant tubulointerstitial kidney disease: not all paths lead to the endoplasmic reticulum

BACKGROUND

Autosomal dominant tubulointerstitial kidney disease (ADTKD) results from mutations in various genes, including REN, UMOD, MUC1, and HNF1B. ADTKD due to REN mutations (ADTKD-REN) is often characterized as a proteinopathy that triggers the endoplasmic reticulum stress (ERS) cascade, potentially sharing similarities with ADTKD-UMOD and ADTKD-MUC1 at the cellular level. This study, inspired by a patient harboring a W17R mutation, investigates ERS activation by this mutation alongside two other renin variants, W10R and L381P.

METHODS

We established stable cell lines expressing both wild-type and mutated renin forms (W17R, W10R, and L381P). Using luciferase reporter assays, RT-qPCR, and confocal microscopy, we evaluated ERS activation, determined the cellular localization of the renin variants, and characterized the mitochondrial network in the W17R line.

RESULTS

The L381P line exhibited ERS activation, including transcriptional upregulation of MANF and CRELD2. No ERS activation was observed in the W17R line, while the W10R line exhibited intermediate characteristics. Notably, the W17R variant was misrouted to the mitochondria resulting in changes of the mitochondrial network organisation.

CONCLUSIONS

ERS activation is not a universal response to different renin mutations in ADTKD-REN. The pathogenesis of the W17R mutation may involve mitochondrial dysfunction rather than the ER pathway, albeit further research is needed to substantiate this hypothesis fully. Testing CRELD2 and MANF as targeted therapy markers for a specific subgroup of ADTKD-REN patients is recommended. Additionally, fludrocortisone treatment has shown efficacy in stabilizing the renal function of our patient over a four-year period without significant side effects.

Plasma renin as a novel prognostic biomarker of sepsis-associated acute respiratory distress syndrome

Sepsis-associated acute respiratory distress syndrome (ARDS) is a life-threatening condition in critical care medicine for which there is a substantial need for early prognostic biomarkers of outcome. The present study seeks to link plasma renin levels and 30-day mortality in sepsis-associated ARDS patients treated at our institution. The Registry of Critical Illness (RoCI) prospectively enrolled patients from the intensive care units (ICU) within a single academic medical center, and a convenience sample of patients with sepsis-associated ARDS was analyzed from this cohort. This study was approved by the Mass General Brigham Institutional Review Boards (IRB) as part of the RoCI, and all procedures performed were in accordance with the ethical standards of the institutional board. From April 2012 to February 2019, a cohort of 32 adult sepsis-associated ARDS patients with 500 µL of plasma samples available on Day 0 and Day 3 of their ICU stay were enrolled. Renin levels were measured twice, on Day 0 and Day 3 via the direct renin enzyme-linked immunosorbent assay (ELISA EIA-525) by DRG diagnostics. Day 0 and Day 3 renin were statistically evaluated via logistic regression to predict 30-day mortality. Direct renin levels of 64 samples were assayed from 32 sepsis-associated ARDS patients (50% male; mean ± SD, 55 ± 13.8 years old). The 30-day hospital mortality rate was 59.4%. Patients who died within 30 days of admission were more likely to have an elevated Day 3 Renin (Odds ratio [OR] = 6, 95% CI 1.25-28.84) and have received vasopressors (OR = 13.33, 95% CI 1.43-123.95). Adjusting for vasopressor use as a proxy for septic shock status, patients with an Elevated Day 3 Renin had a 6.85 (95% CI 1.07-43.75) greater odds of death than those with Low-Normal Day 3 Renin. Patients with sustained Elevated Renin levels from Day 0 to Day 3 had the highest risk of death in a 30-day window. In this study, we found that renin may be a novel biomarker that has prognostic value for patients with sepsis-associated ARDS. Future studies evaluating renin levels in patients with sepsis-associated ARDS are needed to validate these findings.

The scientific rationale and study protocol for the DPP3, Angiotensin II, and Renin Kinetics in Sepsis (DARK-Sepsis) randomized controlled trial: serum biomarkers to predict response to angiotensin II versus standard-of-care vasopressor therapy in the treatment of septic shock

BACKGROUND

Data to support the use of specific vasopressors in septic shock are limited. Since angiotensin II (AT2) was approved by the Food and Drug Administration in 2017, multiple mechanistically distinct vasopressors are available to treat septic shock, but minimal data exist regarding which patients are most likely to benefit from each agent. Renin and dipeptidyl peptidase 3 (DPP3) are components of the renin-angiotensin-aldosterone system which have been shown to outperform lactate in predicting sepsis prognosis, and preliminary data suggest they could prove useful as biomarkers to guide AT2 use in septic shock.

METHODS

The DARK-Sepsis trial is an investigator-initiated industry-funded, open-label, single-center randomized controlled trial of the use of AT2 versus standard of care (SOC) vasopressor therapy in patients admitted to the intensive care unit (ICU) with vasodilatory shock requiring norepinephrine ≥ 0.1 mcg/kg/min. In both groups, a series of renin and DPP3 levels will be obtained over the first 24 h of treatment with AT2 or SOC. The primary study outcome will be the ability of these biomarkers to predict response to vasopressor therapy, as measured by change in total norepinephrine equivalent dose of vasopressors at 3 h post-drug initiation or the equivalent timepoint in the SOC arm. To determine if the ability to predict vasopressor response is specific to AT2 therapy, the primary analysis will be the ability of baseline renin and DPP3 levels to predict vasopressor response adjusted for treatment arm (AT2 versus control) and Sequential Organ Failure Assessment (SOFA) scores. Secondary outcomes will include rates of acute kidney injury, need for mechanical ventilation and kidney replacement therapy, lengths of stay in the ICU and hospital, ICU and hospital mortality, and rates of prespecified adverse events.

DISCUSSION

With an armamentarium of mechanistically distinct vasopressor agents now available, sub-phenotyping patients using biomarkers has the potential to improve septic shock outcomes by enabling treatment of the correct patient with the correct vasopressor at the correct time. However, this approach requires validation in a large definitive multicenter trial. The data generated through the DARK-Sepsis study will prove crucial to the optimal design and patient enrichment of such a pivotal trial.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05824767. Registered on April 24, 2023.

Active plasma renin concentration throughout healthy and complicated pregnancy: a systematic review and meta-analysis

BACKGROUND

Pregnancy is characterized by profound circulatory changes and compensatory adjustments in the renin-angiotensin-aldosterone system (RAAS). Differences in regulatory response may antedate or accompany vascular complicated pregnancy. We performed a systematic review and meta-analysis to delineate the trajectory of active plasma renin concentration (APRC) in healthy pregnancy and compare this to complicated pregnancy.

METHODS

We performed a systematic review and meta-analysis on APRC during normotensive and hypertensive pregnancies, using PubMed (NCBI) and Embase (Ovid) databases. We included only studies reporting measurements during pregnancy together with a nonpregnant reference group measurement. Risk of bias was assessed with QUIPS. Ratio of the mean (ROM) and 95% confidence intervals (CI) of APRC values between pregnant and nonpregnant women were estimated for predefined intervals of gestational age using a random-effects model. Meta-regression was used to analyze APRC over time.

RESULTS

In total, we included 18 studies. As compared to nonpregnant, APRC significantly increased as early as the first weeks of healthy pregnancy and stayed increased throughout the whole pregnancy (ROM 2.77; 95% CI 2.26-3.39). APRC in hypertensive complicated pregnancy was not significantly different from nonpregnancy (ROM 1.32; 95% CI 0.97-1.80).

CONCLUSION

Healthy pregnancy is accompanied by a profound rise in APRC in the first trimester that is maintained until term. In hypertensive complicated pregnancy, this increase in APRC is not observed.

Clinical features, laboratory findings and treatment of juxtaglomerular cell tumors: a systemic review

Juxtaglomerular cell tumors (JGCTs) or reninoma are rare kidney tumors leading to secondary hypertension, and the non-specific clinical manifestations bring about challenges to the diagnosis. This study is to summarize the clinical features, laboratory findings, and treatment of JGCTs. The PubMed, EMBASE database, and manual search were utilized to find all cases, and 158 reports containing 261 patients were identified. Data on patients' demographics, clinical features, diagnostic methods, and treatment options were collected and analyzed. JGCTs occurred predominantly in female patients (female to male ratio, 2.1:1). The median age of patients was 25 years (IQR:18-34 years). Hypertension (97.24%) was the cardinal manifestation. Hypokalemia was reported in 78.71% (159/202) of subjects, and normal serum potassium accounted for 20.79% (42/202). In cases with assessed plasma renin activity (PRA) levels, the median PRA was 7.89 times the upper limit of normal (IQR:3.58-14.41), and 3.82% (5/131) of cases in the normal range. Tumors were detected in 97.8% (175/179) computed tomography (CT), 94.7% (72/76) magnetic resonance imaging (MRI), and 81.5% (110/135) ultrasound, respectively. For 250/261 patients undergoing surgical procedures, 89.14% (197/221), 94.94% (150/158), and 100% (131/131) of patients were restored to normal blood pressure, PRA, and serum potassium, respectively. JGCTs are commonly associated with hypertension, hypokalemia, and hyperreninemia, whereas patients with normotension, normokalemia, and PRA should be systematically pursued after drug-elution lasting for 2 weeks. CT and MRI are more sensitive imaging diagnostic methods. The blood pressure and biochemical parameters of most patients returned to normal after surgery.

Renin-Angiotensin System Inhibitors Suppress the Growth of Leukemia Cells

BACKGROUND/AIM

The renin-angiotensin system (RAS) regulates blood pressure. The RAS is also related to cell growth, and its activation has been reported in various cancer cells. Therefore, we investigated the effects of RAS inhibitors on the in vitro growth of leukemia cell lines.

MATERIALS AND METHODS

THP-1, MV4-11, and TMD7 cells derived from acute myeloid leukemia, K-562 cells from chronic myeloid leukemia, and Jurkat and KOPT-K1 cells from T-lymphoblastic leukemia (T-ALL) with NOTCH1 mutations were used. We used four RAS inhibitors: the renin inhibitor aliskiren, angiotensin-converting enzyme 1 inhibitor captopril, angiotensin II type 1 receptor antagonist azilsartan, and angiotensin II type 2 receptor antagonist PD123319. Cells were cultured with the inhibitors and cell growth was assessed using a colorimetric assay. The expression of signaling proteins was assessed using immunoblotting.

RESULTS

Treatment with aliskiren, azilsartan, or PD123319 suppressed the growth of all cell lines. Captopril treatment suppressed the growth of K-562, KOPT-K1, and MV4-11 cells. Flow cytometric analysis revealed that the growth suppression was due to the induction of apoptosis. Their suppressive effects on normal lymphocytes were milder than those on leukemia cells. Treatment with these inhibitors decreased MYC expression, induced caspase3 and PARP cleavage, and suppressed mTOR signaling. The treatment also suppressed NOTCH1 signaling in T-ALL cells.

CONCLUSION

RAS inhibitors can be repurposed as molecular-targeted drugs for leukemia. However, the concentrations of the inhibitors were much higher than those in the plasma of patients with hypertension. Therefore, further investigation is required for their clinical use.

Aldosterone-to-renin ratio (ARR) as a screening tool for primary aldosteronism (PA)

The aldosterone-to-renin ratio (ARR) is the standard screening test for primary aldosteronism (PA). Because of the poor reproducibility of the ARR, repeat testing is recommended if the result is not compatible with the clinical condition. Various methods to measure renin are used in different hospitals in Taiwan, and the ARR cutoff values also differ among laboratories. The Task Force of Taiwan PA recommend using plasma renin activity (PRA) to calculate ARR instead of direct renin concentration (DRC) unless PRA is unavailable, because PRA is widely used in international guidelines and most studies.

A case of primary aldosteronism with excessive secretion of renin that was unmasked by kidney transplantation

A 42-year-old man showed marked hypokalemia after kidney transplantation. He was diagnosed with hypertension and suffered from acute myocardial infarction at 33 and 38 years of age. At 40 years of age, hemodialysis was introduced. A left adrenal tumor was noted and suspected as a non-functional adrenal adenoma at that time. Therefore, he received a living-donor kidney transplant at 42 years of age. After kidney transplantation, the serum creatinine level dropped. His blood pressure remained high, and the serum potassium level decreased. The PRA and PAC were elevated, and ARR was not elevated. Based on the results of various confirmatory tests and vein sampling, he was diagnosed with excessive secretion of renin from the native kidneys that was complicated by primary aldosteronism (PA), and left nephrectomy and adrenalectomy were performed. The overproduction of aldosterone in the resected adrenal adenoma and over secretion of renin in the kidney with arteriolosclerosis were immunohistologically confirmed. After surgery, the PAC decreased, but the PRA did not decrease. The postoperative serum potassium level improved, and the blood pressure was well controlled with a small dose of medication. This is the first reported case of PA with hyperreninemia after kidney transplantation. It should be noted that PA in dialysis patients and kidney transplant recipients may not fulfill the usual diagnostic criteria of an elevated ARR. In such patients, PA should be suspected based on the absolute value of the PAC and responsiveness to ACTH stimulation, and adrenal and renal vein sampling is required for a definitive diagnosis.

Putative effect of chronic renal failure on granular convoluted tubule of submandibular gland in male rats: Immunohistochemical and ultrastructural study

Objective

This study aimed to investigate the ultrastructural and immunohistochemical changes in the granular convoluted tubule (GCT) of rodents' submandibular gland (SMG) upon theinduction of chronic renal failure.

Material and methods

Thirty young adult Sprague-Dawley rats were randomized into three groups: the Control group, rats received no intervention; the Sham group, rats underwent surgical incision without nephrectomy; the Experimental group, rats underwent surgical procedures to induce chronic renal failure. Afterward, SMG was examined for histological and ultrastructural changes and immunohistochemical staining for Renin.

Results

Histologically, the experimental group demonstrated cytoplasmic vacuolization within the seromucous acini and ducts. Several GCTs were proliferating, whereas others exhibited degenerative changes in the form of disturbed cytoplasmic architecture. On the ultrastructural level, both acini and ductal segments showed degenerative changes Interestingly, immunohistochemical examination of the lining cells of GCT and intralobular ducts of the experimental group revealed the presence of Renin.

Conclusion

Renal failure induced histological, immunohistochemical, and ultrastructural variations within GCTs of SMG.

Monogenic Etiology of Hypertension

Monogenic hypertension encompasses a group of conditions wherein single gene mutations result in increased renal sodium reabsorption manifesting as low renin hypertension. As these diseases are rare, their contribution to hypertension in children and adolescents is often overlooked. Precise diagnosis is essential in those who have not been found to have more common identifiable causes of hypertension in adolescents, since treatment strategies for these rare conditions are specific and different from antihypertensive regimens for the other more common causes of hypertension in this age group. The objective of this review is to provide insight to the rare, monogenic forms of hypertension.

Evolving views on the first two ligands of the angiotensin II type 2 receptor. From putative antagonists to potential agonists?

The renin-angiotensin system is one of the most complex regulatory systems that controls multiple organ functions. One of its key components, angiotensin II (Ang II), stimulates two G-protein coupled class A receptors: the Ang II type 1 (AT1) receptor and the Ang II type 2 (AT2) receptor. While stimulation of the AT1 receptor causes G-protein-dependent signaling and arrestin recruitment, the AT2 receptor seems to have a constitutively active-like conformation and appears to act via G-protein-dependent and -independent pathways. Overstimulation of the AT1 receptor may lead to unwanted effects like inflammation and fibrosis. In contrast, stimulation of the AT2 receptor leads to opposite effects thus restoring the balance. However, the role of the AT2 receptor has become controversial due to beneficial effects of putative AT2 receptor antagonists. The two first synthetic AT2 receptor-selective ligands, peptide CGP42112 and small molecule PD123319, were initially both considered antagonists. CGP42112 was subsequently considered a partial agonist and it was recently demonstrated to be a full agonist. Based on the search-term PD123319 in Pubmed, 1652 studies have investigated putative AT2 receptor antagonist PD123319. Here, we put forward literature that shows beneficial effects of PD123319 alone, even at doses too low for antagonist efficacy. These beneficial effects appear compatible with agonist-like activity via the AT2 receptor. Taken together, a more consistent image of a therapeutic role of stimulated AT2 receptor emerges which may clarify current controversies.

Evaluating renin and aldosterone levels in children with organic acidemia-therapeutic experience with fludrocortisone

Hyporeninemic hypoaldosteronism has been reported in only a few cases with methylmalonic acidemia (MMA) and has been attributed to the renal involvement. This study aims to investigate renin-aldosterone levels along with the renal functions of the patients with organic acidemia. This is a cross-sectional study conducted in patients with MMA, propionic acidemia (PA), and isovaleric acidemia (IVA). Serum renin, aldosterone, sodium, and potassium levels were measured, and glomerular filtration rates (GFR) were calculated. Comparisons were made between the MMA and non-MMA (PA+IVA) groups. Thirty-two patients (MMA:PA:IVA = 14:13:5) were included. The median GFR was significantly lower in the MMA group than in the non-MMA group (p < 0.001). MMA patients had the highest incidence of kidney damage (71.4%), followed by PA patients (23%), while none of the IVA patients had reduced GFR. GFR positively correlated with renin levels (p = 0.015, r = 0.433). Although renin levels were significantly lower in the MMA group than the non-MMA group (p = 0.026), no significant difference in aldosterone levels was found between the two groups. Hyporeninemic hypoaldosteronism was found in 3 patients with MMA who had different stages of kidney damage, and fludrocortisone was initiated, which normalized serum sodium and potassium levels.  Conclusions: This study, which has the largest number of patients among the studies investigating the renin-angiotensin system in organic acidemias to date, has demonstrated that hyporeninemic hypoaldosteronism is not a rare entity in the etiology of hyperkalemia in patients with MMA, and the use of fludrocortisone is an effective treatment of choice in selected cases. What is Known: • Hyperkalemia may be observed in cases of methylmalonic acidemia due to renal involvement and can be particularly prominent during metabolic decompensation. • Hyporeninemic hypoaldosteronism has been reported to be associated with hyperkalemia in only a few cases of methylmalonic acidemia. What is New: • Hyporeninemic hypoaldosteronism was found in one-fifth of cases with methylmalonic acidemia. • Fludrocortisone therapy leads to the normalization of serum sodium and potassium levels.

Effects of Aliskiren Monotherapy versus Amlodipine Monotherapy in Hypertensive Patients with Obesity or Type 2 Diabetes Mellitus

INTRODUCTION

Renin-angiotensin system inhibitors have been reported to exert protective effects against organ damage and failure; however, the impact of the direct renin inhibitor as monotherapy has not been assessed. Here, we investigated the effects of 24-week monotherapy with aliskiren compared to amlodipine in hypertensive patients with type 2 diabetes or obesity.

METHODS

In this randomized intervention study, 62 adult hypertensive patients with visceral obesity (defined as a body mass index [BMI] greater than 25 kg/m2 and a visceral adipose tissue area [VFA] greater than 100 cm2) or type 2 diabetes mellitus (age 57 ± 13, 65% men, BMI 28.8 ± 4.8 kg/m2, VFA 134.8 ± 47.0 cm2, blood pressure 141 ± 16/86 ± 13 mm Hg) were randomized to receive 24-week treatment with aliskiren (max. 300 mg) or amlodipine (max. 10 mg). The primary outcome was the change in VFA at 24 weeks post-treatment.

RESULTS

Change in VFA did not differ significantly from baseline in either group. Systolic blood pressure significantly decreased at 12 weeks (-10 mm Hg, p = 0.001) and 24 weeks (-10 mm Hg, p = 0.001) in the amlodipine group and at 24 weeks (-11 mm Hg, p = 0.001) in the aliskiren group. Diastolic blood pressure significantly decreased at 24 weeks (-6 mm Hg, p = 0.009) only in the amlodipine group. Although the estimated glomerular filtration rates did not significantly change in either group, the logarithm of urinary albumin excretion significantly decreased at 24 weeks only in the aliskiren group (-0.60, p < 0.001). The 24-week changes in the urinary albumin excretion significantly correlated with the changes in the plasma renin activity in the aliskiren group (r = 0.51, p = 0.008).

CONCLUSION

Aliskiren monotherapy did not show any superiority to amlodipine monotherapy on VFA, estimated glomerular filtration rates, or urinary albumin excretion in obese or type 2 diabetic hypertensive patients.

Antioxidant and Renin Inhibitory Activities of Peptides from Food Proteins on Hypertension: A Review

Hypertension is a condition induced by oxidative stress causing an alteration in the endothelium, which increases the risk of suffering from other degenerative diseases. This review compiles the findings on peptides from food proteins with antioxidant and antihypertensive activities. Antihypertensive peptides are mainly focused on renin inhibition. Peptides containing hydrophobic amino acids have antioxidant and renin inhibitory activities, as reported by studies on the biological activity of peptides from various food sources evaluated separately and simultaneously. Peptides from food sources can present multiple biological activities. Moreover, antioxidant peptides have the potential to be evaluated against renin, offering an alternative for hypertension therapy without causing adverse side effects.

Serum renin and prorenin concentrations predict severe persistent acute kidney injury and mortality in pediatric septic shock

BACKGROUND

Studies in critically ill adults demonstrate associations between serum renin concentrations (a proposed surrogate for renin-angiotensin-aldosterone system dysregulation) and poor outcomes, but data in critically ill children are lacking. We assessed serum renin + prorenin concentrations in children with septic shock to determine their predictive ability for acute kidney injury (AKI) and mortality.

METHODS

We conducted a secondary analysis of a multicenter observational study of children aged 1 week to 18 years admitted to 14 pediatric intensive care units (PICUs) with septic shock and residual serum available for renin + prorenin measurement. Primary outcomes were development of severe persistent AKI (≥ KDIGO stage 2 for ≥ 48 h) in the first week and 28-day mortality.

RESULTS

Among 233 patients, day 1 median renin + prorenin concentration was 3436 pg/ml (IQR 1452-6567). Forty-two (18%) developed severe persistent AKI and 32 (14%) died. Day 1 serum renin + prorenin predicted severe persistent AKI with an AUROC of 0.75 (95% CI 0.66-0.84, p < 0.0001; optimal cutoff 6769 pg/ml) and mortality with an AUROC of 0.79 (95% CI 0.69-0.89, p < 0.0001; optimal cutoff 6521 pg/ml). Day 3/day 1 (D3:D1) renin + prorenin ratio had an AUROC of 0.73 (95% CI 0.63-0.84, p < 0.001) for mortality. On multivariable regression, day 1 renin + prorenin > optimal cutoff retained associations with severe persistent AKI (aOR 6.8, 95% CI 3.0-15.8, p < 0.001) and mortality (aOR 6.9, 95% CI 2.2-20.9, p < 0.001). Similarly, D3:D1 renin + prorenin > optimal cutoff was associated with mortality (aOR 7.6, 95% CI 2.5-23.4, p < 0.001).

CONCLUSIONS

Children with septic shock have very elevated serum renin + prorenin concentrations on PICU admission, and these concentrations, as well as their trend over the first 72 h, predict severe persistent AKI and mortality. A higher resolution version of the Graphical abstract is available as Supplementary information.

Vitamin D improves hepatic alterations in ACE1 and ACE2 expression in experimentally induced metabolic syndrome

Metabolic Syndrome (MetS) is a term used to describe a cluster of pathophysiological, biochemical, and metabolic criteria; including high Blood Pressure (BP), high cholesterol, dyslipidaemia, central obesity and Insulin Resistance (IR). The Renin Angiotensin System (RAS) has a regulatory function in BP, hydroelectrolyte balance, and cardiovascular function. RAS is composed of angiotensinogen (AGT), (Ang I), (Ang II), (ACE1), (ACE2), (AT1R), (AT2R), and (Ang 1-7). Vitamin D had been proved to act as a protective factor against MetS. Therefore, the study is pursued to explore vitamin D supplementation roles on hepatic RAS in MetS experimental model. At first, 36 males Albino rats were separated into 4 groups and induced to MetS under controlled circumstances for 3 months. Then, data were collected from blood samples, whereas RNA extracted from liver were analyzed using biochemical and statistical analysis tests. As a result, the major finding was proving that vitamin D can balance the expression of ACE1 and ACE2. Also, confirming that it can improve MetS components by elevating HDL and insulin levels while reducing the levels of BP, cholesterol, LDL, TG, GLU, ALT, AST, and IR. These outcomes may give a new insight into the RAS pathways associated with MetS.

Adiposity, aldosterone and plasma renin activity among African Americans: The Jackson Heart Study

Objective

To analyze associations between adiposity and the renin-angiotensin-aldosterone system (RAAS) in a large African American (AA) cohort.

Methods

Cross-sectional associations of adiposity (body mass index [BMI], waist circumference [WC], waist:height ratio, waist:hip ratio, leptin, adiponectin, leptin:adiponectin ratio [LAR], subcutaneous [SAT] and visceral adipose tissue [VAT], and liver attenuation [LA]) with aldosterone, plasma renin activity (renin), and aldosterone:renin ratio (ARR) were assessed in the Jackson Heart Study using adjusted linear regression models.

Results

A 1-SD higher BMI was associated with a 4.8 % higher aldosterone, 9.4 % higher renin, and 5.0 % lower ARR (all p < 0.05). Log-leptin had the largest magnitude of association with renin (30.2 % higher) and ARR (9.6 % lower), while the strongest association of aldosterone existed for log-LAR (15.3 % higher) (all 1-SD, p < 0.05). SAT was only associated with renin. VAT was associated with higher aldosterone, renin, and ARR. Liver fat was associated with aldosterone and renin, but not ARR. Associations of WC, BMI, and SAT with aldosterone were greater in men while the association with VAT was greater in women (p-interactions < 0.05).

Conclusion

Multiple measures of adiposity are associated with the RAAS in AAs. Further studies should examine the role of RAAS in obesity-driven cardiometabolic diseases.

Increasing angiotensin-converting enzyme concentrations and absent angiotensin-converting enzyme activity are associated with adverse kidney outcomes in pediatric septic shock

BACKGROUND

Sepsis-induced endothelial dysfunction is proposed to cause angiotensin-converting enzyme (ACE) dysfunction and renin-angiotensin-aldosterone system (RAAS) derangement, exacerbating vasodilatory shock and acute kidney injury (AKI). Few studies test this hypothesis directly, including none in children. We measured serum ACE concentrations and activity, and assessed their association with adverse kidney outcomes in pediatric septic shock.

METHODS

A pilot study of 72 subjects aged 1 week-18 years from an existing multicenter, observational study. Serum ACE concentrations and activity were measured on Day 1; renin + prorenin concentrations were available from a previous study. The associations between individual RAAS components and a composite outcome (Day 1-7 severe persistent AKI, kidney replacement therapy use, or mortality) were assessed.

RESULTS

50/72 subjects (69%) had undetectable ACE activity (< 2.41 U/L) on Day 1 and 27/72 (38%) developed the composite outcome. Subjects with undetectable ACE activity had higher Day 1 renin + prorenin compared to those with activity (4533 vs. 2227 pg/ml, p = 0.017); ACE concentrations were no different between groups. Children with the composite outcome more commonly had undetectable ACE activity (85% vs. 65%, p = 0.025), and had higher Day 1 renin + prorenin (16,774 pg/ml vs. 3037 pg/ml, p < 0.001) and ACE concentrations (149 vs. 96 pg/ml, p = 0.019). On multivariable regression, increasing ACE concentrations (aOR 1.01, 95%CI 1.002-1.03, p = 0.015) and undetectable ACE activity (aOR 6.6, 95%CI 1.2-36.1, p = 0.031) retained associations with the composite outcome.

CONCLUSIONS

ACE activity is diminished in pediatric septic shock, appears uncoupled from ACE concentrations, and is associated with adverse kidney outcomes. Further study is needed to validate these findings in larger cohorts.

Prognostic role of the immunohistochemical expression of proteins related to the renin-angiotensin system pathway in nonmetastatic clear cell renal cell carcinoma

INTRODUCTION

Stage migration has been observed in renal cell carcinoma (RCC) in recent decades; however, mortality rates have continuously increased in some countries. Tumoral factors have been characterized as major predictors of RCC. Nonetheless, this concept can be improved by combining these tumoral factors with other variables, including biomolecular factors.

PURPOSE

This study aimed to assess the immunohistochemical (IHC) expression and prognostic value of renin (REN), erythropoietin (EPO), and cathepsin D (CTSD), and to evaluate whether the concomitant expression of these markers can influence the prognostic outcomes in patients without metastasis.

MATERIAL AND METHODS

In total, 729 patients with clear cell RCC (ccRCC) who underwent surgical treatment between 1985 and 2016 were evaluated. All the cases in the tumor bank were reviewed by dedicated uropathologists. The IHC expression patterns of the markers were assessed using a tissue microarray. REN and EPO were classified as "positive" or "negative" expression. CTSD was grouped into "absent or weak expression" or "strong expression." Associations between clinical and pathological variables and the studied markers, in addition to 10-year overall survival (OS), cancer-specific survival (CSS), and recurrence-free survival rates, were described.

RESULTS

REN and EPO expressions were positive in 70.6% and 86.6% of patients, respectively. Absent or weak and strong expressions of CTSD were observed in 58.2% and 41.3% of the patients, respectively. EPO expression had no impact on survival rates even when assessed concomitantly with REN. Negative REN expression was associated with advanced age, preoperative anemia, larger tumors, perirenal fat, hilum or renal sinus infiltration, microvascular invasion, necrosis, high nuclear grade, and clinical stages III to IV. In contrast, strong CTSD expression was associated with poor prognostic variables. The expression patterns of REN and CTSD were unfavorable predictors of the 10-year OS and CSS. In particular, the combination of negative REN and strong CTSD expression had a negative impact on these rates, including a higher risk of recurrence.

CONCLUSION

Loss of REN expression and strong CTSD expression were independent prognostic factors in nonmetastatic ccRCC, particularly when the concomitant expression pattern of both markers was present. EPO expression did not influence survival rates in this study.

Misrouting to mitochondria of renin carrying dominant mutations in the leader peptide or pro-segment

Autosomal Dominant Tubulointerstitial Kidney Disease, a rare genetic disorder characterised by progressive chronic kidney disease, is caused by mutations in different genes including REN, encoding renin. Renin is a secreted protease composed of 3 domains: the leader peptide allowing insertion in the endoplasmic reticulum (ER), a pro-segment regulating its activity, and the mature part. Mutations in mature renin lead to ER retention of mutant protein and to late onset disease, while mutations in the leader peptide, associated with defective ER translocation, and mutations in the pro-segment, accumulating in the ER-to-Golgi compartment, lead to a more severe, early-onset disease. In this study we demonstrate a common, unprecedented effect of mutations in the leader peptide and pro-segment as they lead to full or partial mistargeting of mutated protein to mitochondria. The mutated pre-pro sequence of renin is necessary and sufficient to drive mitochondrial rerouting, mitochondrial import defect and fragmentation. Mitochondrial localisation and fragmentation are also observed for wild type renin when affecting ER translocation. These results expand the spectrum of cellular phenotypes associated with ADTKD-REN mutations providing new insight into the disease molecular pathogenesis.

Renin, aldosterone, the aldosterone-to-renin ratio, and incident hypertension among normotensive subjects from the general population

AIMS

To investigate the predictive ability of direct plasma renin and aldosterone concentrations as well as their ratio [aldosterone-to-renin (ARR)] for incident hypertension in the general population.

METHODS AND RESULTS

Concentration of renin and aldosterone were measured by a chemiluminescence immunoassay using the fully automated LIAISON® platform (DiaSorin) among 5362 participants of the population-based Gutenberg Health Study, who were normotensive and had no clinically overt cardiovascular disease at baseline. During a follow-up period of 5 years, 18.6% (n = 996) developed a new-onset hypertension. Comparing extreme quartiles of biomarker distribution, the relative risk (RR) for incident arterial hypertension was found to be 1.58 [95% confidence interval (CI) 1.25-2.00; P = 0.00015; Q1 vs. Q4ref] for renin; 1.29 (95% CI 1.05-1.59, P = 0.018; Q4 vs. Q1ref) for aldosterone and 1.70 (95% CI 1.33-2.12; P < 0.0001; Q4 vs. Q1ref) for ARR after multivariable adjustment in men. In females, only high ARR was independently predictive for incident hypertension over 5 years [RR 1.29 (95% CI 1.04-1.62); P = 0.024]. Even in the subgroup of individuals having biomarker concentrations within the reference range, high ARR was predictive for new-onset hypertension in men [RR 1.44 (95% CI 1.13-1.83); P = 0.003]. Finally, synergistic effects of co-prevalent obesity and ARR on incident hypertension were also demonstrated, resulting in markedly higher risk estimates as seen for biomarker alone [RR of 2.70 (95% CI 2.05-3.6) for Q4 of ARR and having body mass index ≥ 30 kg/m2 vs. low ARR (Q1ref) and normal weight; P < 0.0001].

CONCLUSION

Among normotensives from the general population ARR possesses a stronger predictive value for incident hypertension than renin or aldosterone alone. The prediction of arterial hypertension by ARR was even stronger in obese subjects.

Levistolide A ameliorates fibrosis in chronic kidney disease via modulating multitarget actions in vitro and in vivo

AIMS

The increasing incidence of chronic kidney disease (CKD) urgently calls for effective nephroprotective agents. Traditional Chinese Medicine Angelica sinensis and its formula are well known for CKD therapy, but the underlying mechanisms and effective substances of reno-protective effects remain unclear. To this end, we isolated eleven ligustilide dimers (1-11) from A. sinensis and examined the molecular mechanism of their nephroprotective effects.

MAIN METHODS

Because of internal RAS playing an important role in CKD, we used renin expression as a target and screened preliminarily for antifibrotic effects of ligustilide dimers (1-11) by constructing a dual luciferase reporter gene in vitro. Furthermore, the reno-protective effects of the ligustilides and their underlying mechanism were investigated in TGF-β1-stimulated HK-2 cells and 5/6 nephrectomy (Nx) mice.

KEY FINDINGS

The ligustilide dimers exhibited anti-fibrotic effects by inhibiting human renin (hREN) promoter activity to decrease renin expression and down-regulate the expression of fibrosis-related factors, including α-SMA, collagen I, and fibronectin in vitro. Levistolide A (LA) and angeolide keto ester (AK) were screened out to identify their ability and underlying mechanism for treating CKD. Experimental validation further indicated that LA or AK treatment inhibited the expression of key molecules in RAS, TGF-β1/Smad, and MAPK pathways to downregulate ECM deposition. Furthermore, LA obviously meliorated renal injury in 5/6 Nx mice through ameliorating oxidant stress, inflammation, apoptosis and renal fibrosis.

SIGNIFICANCE

The experimental results demonstrated that ligustilide dimers were potential nephroprotective agents. LA might be an attractive drug candidate for renin-targeted CKD therapy.

Plasma renin activity variation following admission predicts patient outcome in acute decompensated heart failure with reduced and mildly reduced ejection fraction

Plasma renin activity (PRA) level at admission is reported to be a prognostic predictor of acute decompensated heart failure (ADHF) patients. Although PRA is affected during hospitalization by several factors including fluid volume and drug titration, whether the changes in PRA levels during hospitalization (ΔPRA) are associated with prognosis of ADHF patients are largely unknown.

PURPOSE

Investigate the predictive impact of ΔPRA on the prognosis of ADHF patients with reduced ejection fraction (HFrEF) and mildly reduced ejection fraction (HFmrEF).

METHODS

Retrospectively analyzed consecutive 116 HFrEF and HFmrEF patients admitted for ADHF. PRA measurements were acquired at admission and at discharge. The primary outcome was a composite of cardiovascular death and HF re-hospitalization.

RESULTS

Out of 116 patients, 85 had PRA measurements both at admission and at discharge. Compared to admission, PRA level was significantly higher at discharge (0.8 (IQR 0.3-2.2) to 2.8 (IQR 1.0-7.2), p < 0.001). Tertiary groups ranked by PRA level on admission showed trend of poor prognosis in order of high, mid, and low PRA level (p = 0.07). On the contrary, PRA level at discharge significantly differentiated the prognosis and was poor in order of high, low, and mid (p = 0.026). Next, when the participants were divided into tertiary groups ranked by ΔPRA, prognosis worsened in the order of "minimal", "decreasing", and the "increasing" tier. Cubic splines analysis also indicate a similar tendency.

CONCLUSIONS

In ADHF patients with HFrEF and HFmrEF, patients with minimal ΔPRA showed the better prognosis over the those with either increasing or decreasing.

Uric acid accumulation in the kidney triggers mast cell degranulation and aggravates renal oxidative stress

The accumulation of uric acid (UA) in the body can lead to the occurrence of hyperuricemia or uric acid nephropathy. Mast cells (MCs) increase oxidative stress and release renin to promote the production of Ang II. The aim of this study was to investigate the effect of UA on MCs in rat kidneys and the association between MCs and renal injury. Our results show that UA accumulation in the kidney stimulated the degranulation of MCs and the release of renin to promote Ang II production, resulting in renal oxidative stress, mitochondrial structural damage, and microvascular system damage. The expression of urate-related transporters was regulated by the UA level and serum urinary toxins levels were substantially elevated in hyperuricemia. Administration of the MCs membrane stabilizer sodium cromoglycate (SCG) or the angiotensin receptor antagonist Valsartan decreased the production of renin and Ang II and relieved renal oxidative stress, mitigated mitochondrial structural damage and microvascular system damage, and promoted the excretion of UA and urinary toxins by increasing the expression of urate-related transporters. These results demonstrate that the accumulation of UA in the kidney can trigger the degranulation of MCs and promote the development of renal oxidative stress. Administration of SCG and Valsartan ameliorated UA-induced renal injury by inhibiting MCs degranulation and reducing renal oxidative stress by inhibiting renin and Ang II production and accelerating renal clearance of UA and uremic toxins.

Importance of dietary salt restriction for patients with primary aldosteronism during treatment with mineralocorticoid receptor antagonists: The potential importance of post-treatment plasma renin levels

We measured dietary salt intake in 26 patients with primary aldosteronism treated with mineralocorticoid receptor antagonists and evaluated whether plasma renin levels were affected by dietary salt intake pre-treatment and post 6 months of mineralocorticoid receptor antagonist treatment. The dietary salt intake level was calculated using spot urine sodium and creatinine concentrations, body weight, height, and age. The clinical parameters pre- and post- treatment were compared. The systolic and diastolic blood pressure levels decreased, and the serum potassium and active renin concentration increased significantly. Although the dietary salt intake did not change after treatment, the differences in dietary salt intake and active renin concentration pre- and post- treatment were inversely correlated (r = -0.418, p = 0.03). The 26 patients were divided into two groups with active renin concentration levels ≥5 pg/mL (Group 1) and <5 pg/mL (Group 2) after treatment. The Group parameters did not differ pre- and post- treatment. Group 1 evidenced improvements in systolic and diastolic blood pressures, and the potassium level and active renin concentration over time; Group 2 did not. Group 1 evidenced no significant correlation between the differences in dietary salt intake and active renin concentration levels (r = -0.481, p = 0.11) but Group 2 showed a strong inverse correlation (r = -0.7599, p = 0.01). In conclusion, we found that an active renin concentration level <5 pg/mL post-mineralocorticoid receptor antagonist treatment may indicate that salt sensitivity has not adequately improved, emphasizing the importance of measuring plasma renin levels after such treatment.

Renin and electrolytes indicate the mineralocorticoid activity of fludrocortisone: a 6 year study in primary adrenal insufficiency

CONTEXT

Fludrocortisone (FC) is the mineralocorticoid (MC) replacement treatment for patients with primary adrenal insufficiency (PAI).

OBJECTIVE

To explore the dose of FC treatment and its relationship with glucocorticoid therapy, sodium, potassium, renin and clinical parameters.

SETTING

Monocentric cohort.

PATIENTS

Data of 193 patients with PAI (130 autoimmune) were collected during baseline (T0), intermediate (T1) and last follow-up visit (T2, respectively, after a mean of 38 and 72 months).

MAIN OUTCOME MEASURE

Utility of endocrine and clinical parameters to titrate FC dose.

RESULTS

FC dose (50-75 μg/daily) was stable in the follow-up in half patients. The MC activity of FC was dose-dependent: we observed a reduced but significant positive linear correlation between FC dose and sodium (r = 0.132) and negative linear correlation between FC and potassium (r = - 0.162) or renin (r = - 0.131, all p < 0.01). An overall reduction in the FC dose was observed at T2 in the group with longer follow-up (> 60 months, p < 0.05). Higher doses of FC were observed in patients with low-normal renin, especially in autoimmune PAI (86 vs 65 μg/daily, p < 0.05). On the contrary, reduced sodium and increased potassium levels were observed in patients with high renin at T2. The number of cardiovascular events (15 in the whole cohort) was similar in patients sorted by renin levels or FC dose.

CONCLUSIONS

Renin and electrolytes can indicate the MC activity of FC treatment: they should be routinely evaluated and used to titrate its dose that can be reduced in the long-term follow-up.

Activation of Piezo1 downregulates renin in juxtaglomerular cells and contributes to blood pressure homeostasis

BACKGROUND

The synthesis and secretion of renin in juxtaglomerular (JG) cells are closely regulated by the blood pressure. To date, however, the molecular identity through which JG cells respond to the blood pressure remains unclear.

RESULTS

Here we discovered that Piezo1, a mechanosensitive ion channel, was colocalized with renin in mouse kidney as well as As4.1 cells, a commonly used JG cell line. Activation of Piezo1 by its agonist Yoda1 induced an intracellular calcium increase and downregulated the expression of renin in these cells, while knockout of Piezo1 in JG cells abolished the effect of Yoda1. Meanwhile, mechanical stress using microfluidics also induced an intracellular calcium increase in wildtype but not Piezo1 knockout JG cells. Mechanistically, we demonstrated that activation of Piezo1 upregulated the Ptgs2 expression via the calcineurin-NFAT pathway and increased the production of Ptgs2 downstream molecule PGE₂ in JG cells. Surprisingly, we discovered that increased PGE₂ could decreased the renin expression through the PGE₂ receptor EP1 and EP3, which inhibited the cAMP production in JG cells. In mice, we found that activation of Piezo1 significantly downregulated the renin expression and blood pressure in wildtype but not adeno-associated virus (AAV)-mediated kidney specific Piezo1 knockdown mice.

CONCLUSIONS

In summary, these results revealed that activation of Piezo1 could downregulate the renin expression in JG cells and mice, subsequently a reduction of blood pressure, highlighting its therapeutic potential as a drug target of the renin-angiotensin system.

An explorative epigenome-wide association study of plasma renin and aldosterone concentration in a Ghanaian population: the RODAM study

BACKGROUND

The epigenetic regulation of the renin-angiotensin-aldosterone system (RAAS) potentially plays a role in the pathophysiology underlying the high burden of hypertension in sub-Saharan Africans (SSA). Here we report the first epigenome-wide association study (EWAS) of plasma renin and aldosterone concentrations and the aldosterone-to-renin ratio (ARR).

METHODS

Epigenome-wide DNA methylation was measured using the Illumina 450K array on whole blood samples of 68 Ghanaians. Differentially methylated positions (DMPs) were assessed for plasma renin concentration, aldosterone, and ARR using linear regression models adjusted for age, sex, body mass index, diabetes mellitus, hypertension, and technical covariates. Additionally, we extracted methylation loci previously associated with hypertension, kidney function, or that were annotated to RAAS-related genes and associated these with renin and aldosterone concentration.

RESULTS

We identified one DMP for renin, ten DMPs for aldosterone, and one DMP associated with ARR. Top DMPs were annotated to the PTPRN2, SKIL, and KCNT1 genes, which have been reported in relation to cardiometabolic risk factors, atherosclerosis, and sodium-potassium handling. Moreover, EWAS loci previously associated with hypertension, kidney function, or RAAS-related genes were also associated with renin, aldosterone, and ARR.

CONCLUSION

In this first EWAS on RAAS hormones, we identified DMPs associated with renin, aldosterone, and ARR in a SSA population. These findings are a first step in understanding the role of DNA methylation in regulation of the RAAS in general and in a SSA population specifically. Replication and translational studies are needed to establish the role of these DMPs in the hypertension burden in SSA populations.

Pharmacophore modelling, docking and molecular dynamic simulation studies in the discovery of potential human renin inhibitors

Hypertension is the main cause of human death and the Renin- Angiotensin- Aldosterone System (RAAS) has a key role in the control of human blood pressure. In this research a multi-step virtual screening strategy was applied in order to find new potential renin inhibitors. The crystal structure of renin-aliskiren complex was explored and receptor-ligand pharmacophore model was developed and validated using pharmit. ZINC database was screened by pharmacophore model and Lipinski's rule of five. Thereafter, the retrieved hits were docked in the active site of renin by using Vina. ADME parameters and toxicity of the filtered compounds were approximated using in silico methods and the selected compounds were subjected to high performance docking in order to improve the accuracy of screening. The non-bond interactions of the hit molecules with renin were explored and the compounds with the highest affinity and appropriate interactions were selected. In the last step, molecular dynamic simulation studies were performed on the complex of renin with aliskiren and three top-ranked structures including ZINC6085004, ZINC426421106, and ZINC5481346. RMSD, RMSF, Rg and number of hydrogen bonds were calculated. The binding free energy was calculated using the MM/PBSA method. The result of MD simulation indicated the stable binding of ZINC426421106 and ZINC5481346 with the active site of renin. According to this in-silico study these two compounds are drug-like, nontoxic, and have a high potential for inhibiting renin and could serve as appropriate lead molecules for the development of renin inhibitors as antihypertensive agents.

[Regulatory Effect of Vitamin D on Renin Expression at Maternal-Fetal Interface]

Objective

To investigate the regulatory effect and mechanism of vitamin D on the local renin-angiotensin system at maternal-fetal interface in the pathological process of preeclampsia (PE).

Methods

The mRNA and protein expression of renin in decidua of normal pregnancy and PE placentas was determined by RT-PCR and Western blot. Normal decidual tissues were treated with active and inactive vitamin D for 48 h in vitro and the expressions of renin and vitamin D deactivating enzyme CYP24A1 were determined by RT-PCR and Western blot. Normal decidual stromal cells and glandular epithelial cells were isolated and purified, and identified by immunocytochemical staining. RT-PCR was used to examine the mRNA of vdr, cyp27 b1, cyp24 a1, and renin in the two types of cells and in decidual tissue, and the mRNA products were subjected to gel electrophoresis. These two cell types were treated with active and inactive vitamin D in vitro and the expressions of renin and vitamin D deactivating enzyme CYP24A1 were determined by RT-PCR and Western blot. Decidual gland epithelial cells were treated with protein kinase A (PKA) activator forskolin or inhibitor H89 to explore the interaction between PKA pathway and vitamin D in the regulation of renin expression.

Results

The expression of renin in PE decidua was significantly higher than that of normal control at transcriptional and translational levels ( P<0.05). Vitamin D treatment could significantly down-regulate the expression of renin in normal decidua tissues ( P<0.05), while it significantly up-regulated CYP24A1 expression ( P<0.001). Decidual stromal cells and gland epithelial cells were successfully isolated from decidual tissue. Compared with that in decidual stromal cells, the mRNA level of vitamin D-related molecules in gland epithelial cells was more similar to that in decidual tissue. Active or inactive vitamin D treatment significantly inhibited the expression of renin in glandular epithelial cells ( P<0.05), but the expression of renin in decidual stromal cells was not affected. However, the treatment of active or inactive vitamin D in these two kinds of cells significantly increased the expression of CYP24A1 ( P<0.001). Active vitamin D could significantly inhibit the upregulation of renin by PKA agonist forskolin, and could inhibit the expression of renin through synergy with PKA inhibitor H89.

Conclusion

The expression of renin in placental decidua is up-regulated in patients with PE, and the activation of local renin-angiotensin system at the maternal-fetal interface may be involved in the pathogenesis of PE. Vitamin D can specifically down-regulate renin expression in human decidual gland epithelial cells by competing with the PKA pathway. Vitamin D supplementation may have potential value for clinical intervention of PE.

Juxtaglomerular cell tumor: report of a case with unusual presentation

Juxtaglomerular cell tumor is a benign, renin-secreting neoplasm. The tumor arises from the juxtaglomerular apparatus cells of the kidney. Because the tumor is hormonally active, patients usually suffer from hypokalemia, hyperaldosteronism, and hypertension. Herein, we describe a case of a 19-year-old Asian female with a somewhat unusual presentation.

A 19-year-old Asian female presented with upper extremity weakness, numbness, and tingling. On physical examination, the only notable finding was hypertension. Extensive workup revealed elevated aldosterone level and plasma renin activity. CT scan of the abdomen revealed a 2.2 cm mass in the lower pole of the left kidney. The mass was resected by partial nephrectomy. On microscopic evaluation, the tumor had glomoid appearance with sheets of uniform, round to polygonal cells with clear to eosinophilic cytoplasm. Immunohistochemical stains showed the tumor cells to be positive for CD117, CD34 and CD10 and negative for ER, PR, CK7, PAX-8, pan-cytokeratin, EMA, S100, Melan-A, HMB45, SMA and CAIX. Diagnosis of Juxtaglomerular cell tumor was rendered. This case highlights the importance of a regular physical exam and a high index of suspicion in patients presenting with unusual complaints.

Association of cardiovascular disease risk and changes in renin levels by mineralocorticoid receptor antagonists in patients with primary aldosteronism

A recent report stated that patients with primary aldosteronism who remain renin suppressed during mineralocorticoid receptor antagonist treatment might have a higher risk of developing cardiovascular disease than those with unsuppressed renin activity. We retrospectively investigated the incidence of composite cardiovascular disease and risk factors for cardiovascular disease in 1115 Japanese patients with primary aldosteronism treated with mineralocorticoid receptor antagonists. The median follow-up period was 3.0 years, and the incidence of cardiovascular events was very low (2.1%) throughout 5 years of follow-up. Changes in plasma renin activity from before to after mineralocorticoid receptor antagonist treatment were divided into three groups based on tertile, low, intermediate, and high plasma renin activity change groups, with incidences of cardiovascular disease events of 2.1%, 0.5%, and 3.7%, respectively. Multivariate Cox regression analysis revealed age (adjusted hazard ratio, 1.07; 95% confidence interval, [1.02-1.12]) and body mass index (adjusted hazard ratio, 1.13 [1.04-1.23]) as independent risk factors for cardiovascular disease. The high plasma renin activity change group had significantly higher cardiovascular disease risk with mineralocorticoid receptor antagonist treatment than the intermediate plasma renin activity change group (adjusted hazard ratio, 5.71 [1.28-25.5]). These data suggest that a high change in renin level after mineralocorticoid receptor antagonist treatment may not necessarily predict a better prognosis of cardiovascular disease in patients with primary aldosteronism.

Structural and Dynamic Investigation of non-synonymous variations in Renin-AGT complex revealed altered binding via hydrogen bonding network reprogramming to accelerate the hypertension pathway

Hypertension is one of the major issues worldwide and one of the main factors involved in heart and kidney failure. Angiotensinogen and renin are key components of the renin-angiotensin-aldosterone system (RAAS), which plays an indispensable role in hypertension. The aimed of this study to find out the non-synonymous mutations and structure-based mutation-function correlation in the Renin-AGT complex and reveal the most deleterious mutations to accelerated hypertension. In the current study, we employed computational modelling and molecular simulation approaches to demonstrate the impact of specific mutations in the REN-AGT interface in hypertension. Computational algorithms i.e. PhD-SNP, PolyPhen-1, MAPP, SIFT, SNAP, PredictSNP, PolyPhen-2, and PANTHER predicted 20 mutations as deleterious in AGT while only five mutations were conformed as deleterious in the Renin protein. Investigation of the bonding analysis revealed that two mutations S107L and V193F in Renin altered the hydrogen-bonding paradigm at the interface site. Furthermore, exploration of structural-dynamic behaviors demonstrated by that these mutations also increases the structural stability to regulate the expression of disease pathway. The flexibility index of each residues and structural compactness analysis further validated the findings by portraying the difference in the dynamic behavior in contrast to the wild type. Binding energy calculations based on molecular mechanics/generalized Born surface area (MM/GBSA) methods were used which further established the binding differences between the wild type, S107L, and V193F mutant variants. The total binding energy for wild type, S107L, and V193F were reported to be -27.79 kcal/mol, -47.72 kcal/mol, and -38.25 kcal/mol respectively. In conclusion, these two mutations increase the binding free energy alongside the docking score to enhance the binding between Renin and AGT to overexpress this pathway in a hypertension disease condition. Patients with these mutations may be screened for potential therapeutic intervention.

Inverse Salt Sensitivity of Blood Pressure: Mechanisms and Potential Relevance for Prevention of Cardiovascular Disease

PURPOSE OF REVIEW

To review the etiology of inverse salt sensitivity of blood pressure (BP).

RECENT FINDINGS

Both high and low sodium (Na⁺) intake can be associated with increased BP and cardiovascular morbidity and mortality. However, little is known regarding the mechanisms involved in the increase in BP in response to low Na⁺ intake, a condition termed inverse salt sensitivity of BP, which affects approximately 15% of the adult population. The renal proximal tubule is important in regulating up to 70% of renal Na⁺ transport. The renin-angiotensin and renal dopaminergic systems play both synergistic and opposing roles in the regulation of Na⁺ transport in this nephron segment. Clinical studies have demonstrated that individuals express a "personal salt index" (PSI) that marks whether they are salt-resistant, salt-sensitive, or inverse salt-sensitive. Inverse salt sensitivity results in part from genetic polymorphisms in various Na⁺ regulatory genes leading to a decrease in natriuretic activity and an increase in renal tubular Na⁺ reabsorption leading to an increase in BP. This article reviews the potential mechanisms of a new pathophysiologic entity, inverse salt sensitivity of BP, which affects approximately 15% of the general adult population.

Plasma renin, aldosterone, and urinary prostaglandin E2 levels in children with hypocalcemia due to vitamin D deficiency rickets

We investigated the effect of hypocalcemia on plasma renin, aldosterone, and urine PGE₂ levels in children with vitamin D deficiency rickets (VDDR). In the study group, 25 patients with VDDR-induced hypocalcemia were treated with a single dose of 150,000-300,000 IU cholecalciferol and 50 mg/kg/day elemental Ca for 10 days. On any day between 21th and 30th days after the treatment, the patients' clinical, biochemical and radiologic findings were re-evaluated. The healthy children with the same sex and similar age as the study group comprised the control group. Plasma sodium (Na), potassium (K), calcium (Ca), phosphorus (P), alkaline phosphatase (ALP), parathyroid hormone (PTH), 25- hydroxy vitamin D (25OHD), renin, aldosterone; and urinary Ca, creatinine (Cr) and prostaglandin E₂ (PGE₂) levels were measured in both the study (pre-treatment and post-treatment) and the control group. Plasma Ca, P, 25OHD and renin levels and urinary PGE₂/Cr ratio in the post-treatment group were significantly higher than those in the pre-treatment group while K, ALP, and PTH concentrations were significantly lower. Plasma ALP and PTH levels in pre-treatment group were significantly higher than in the control group while Ca, P, 25OHD, aldosterone and renin concentrations and urinary PGE₂/Cr ratio were significantly lower. Post-treatment plasma Ca level was significantly decreased in normal limits compared to the control group while other biochemical parameters were not different from the control group. Plasma Ca concentration was positively correlated with renin level and urinary PGE₂/Cr ratio. The findings suggest that hypocalcemia may inhibit the production of renin, aldosterone and PGE₂ and a blunt aldosterone secretion may develop even after recovery from hypocalcemia.

Flexible and multifaceted: the plasticity of renin-expressing cells

The protease renin, the key enzyme of the renin–angiotensin–aldosterone system, is mainly produced and secreted by juxtaglomerular cells in the kidney, which are located in the walls of the afferent arterioles at their entrance into the glomeruli. When the body’s demand for renin rises, the renin production capacity of the kidneys commonly increases by induction of renin expression in vascular smooth muscle cells and in extraglomerular mesangial cells. These cells undergo a reversible metaplastic cellular transformation in order to produce renin. Juxtaglomerular cells of the renin lineage have also been described to migrate into the glomerulus and differentiate into podocytes, epithelial cells or mesangial cells to restore damaged cells in states of glomerular disease. More recently, it could be shown that renin cells can also undergo an endocrine and metaplastic switch to erythropoietin-producing cells. This review aims to describe the high degree of plasticity of renin-producing cells of the kidneys and to analyze the underlying mechanisms.

Follicle stimulating hormone promotes production of renin through its receptor in juxtaglomerular cells of kidney

BACKGROUND

Post-menopausal hypertension has been attributed solely to declining estrogen levels. The purpose of the research is to elucidate the mechanism by which follicle stimulating hormone(FSH) increases renin production involved in the regulation of blood pressure.

METHODS

The expression of follicle stimulating hormone receptors (FSHRs) in renal juxtaglomerular cells and a As4.1 juxtaglomerular mouse cell line was evaluated. We established a mouse model by ovariectomy (OVX). Ovariectomized mice were treated with gonadotropin-releasing hormone agonist (GnRHa) (OVX + GnRHa). Ovariectomized mice initially received physiological doses of estrogen and were then injected with recombinant FSH (OVX + E + FSH).

RESULTS

We found that FSHR was expressed in mouse renal juxtaglomerular cells labeled by renin antibody and in As4.1 cells. FSH promoted renin synthesis via Gsα-coupled FSHRs that activated protein kinase A, cyclic adenosine monophosphate(cAMP) response element-binding protein, extracellular signal-regulated kinase (Erk1/2), Protein kinase B(AKT), and c-Jun N-terminal kinase signaling pathways in As4.1 cells. We found increased serum FSH levels in the ovariectomized mouse with concurrent increases in renin, angiotensin II, heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial blood pressure (MAP). Additionally, increases in serum renin, angiotensin II, HR, SBP, DBP, and MAP were reduced by the additional injection of GnRHa. Exogenous FSH administration completely reversed decreases in renin, angiotensin II, HR, SBP, DBP, and MAP even in mice that received physiological doses of estrogen to maintain normal estradiol levels.

CONCLUSIONS

Elevated FSH stimulates renin production involving a mechanism that may be relevant to the expression of FSH receptors in renal juxtaglomerular cells.

Autosomal dominant tubulointerstitial kidney disease: more than just HNF1β

Autosomal dominant tubulointerstitial kidney disease (ADTKD) refers to a group of disorders with a bland urinary sediment, slowly progressive chronic kidney disease (CKD), and autosomal dominant inheritance. Due to advances in genetic diagnosis, ADTKD is becoming increasingly recognized as a cause of CKD in both children and adults. ADTKD-REN presents in childhood with mild hypotension, CKD, hyperkalemia, acidosis, and anemia. ADTKD-UMOD is associated with gout and CKD that may present in adolescence and slowly progresses to kidney failure. HNF1β mutations often present in childhood with anatomic abnormalities such as multicystic or dysplastic kidneys, as well as CKD and a number of other extra-kidney manifestations. ADTKD-MUC1 is less common in childhood, and progressive CKD is its sole clinical manifestation, usually beginning in the late teenage years. This review describes the pathophysiology, genetics, clinical characteristics, diagnosis, and treatment of the different forms of ADTKD, with an emphasis on diagnosis. We also present data on kidney function in children with ADTKD from the Wake Forest Rare Inherited Kidney Disease Registry.

The effect of renin-angiotensin-aldosterone system inhibitors on continuous and binary kidney outcomes in subgroups of patients with diabetes: a meta-analysis of randomized clinical trials

Introduction

Diabetic nephropathy is the leading cause of kidney failure. Clinical practice guidelines recommend prescribing renin–angiotensin aldosterone system inhibitors (RAASi) to prevent diabetic nephropathy at any stage. We conducted this systematic review and meta-analysis to compare the effects of RAASi with placebo and other antihypertensive agents in adults with diabetes on continuous and binary kidney outcomes to provide a comprehensive review of the class effect of RAASi on several subgroups.

Methods

A systematic electronic search to identify randomized clinical trials of a duration of ≥ 12 months that recruited ≥ 50 adult participants with type 1 or 2 diabetes with any stage of chronic kidney disease and proteinuria was conducted in MEDLINE, CINAHL, EMBASE, and Cochrane library with no language restriction. Studies were screened against the inclusion and exclusion criteria by two reviewers independently.

Results

In this meta-analysis, evidence was drawn from 26,551 patients with diabetes from 46 studies. Our analysis shows that RAASi were better than placebo in reducing SrCr (the raw mean difference [RMD] = -13.4 μmol/L; 95%CI: -16.78; -10.01) and albuminuria levels (standardized mean difference [SMD] = -1; 95%CI: -1.57, -0.44, I² = 96%). When compared to other active treatments, RAASi did not reduce SrCr (RMD = 0.03 μmol/L; 95%CI: -6.4, 6.10, I² = 76%), caused a non-significant reduction of GFR levels (RMD = -1.21 mL/min; 95%CI: -4.52, 2.09, I² = 86%), and resulted in modest reduction of albuminuria levels (SMD = -0.55; 95%CI: -0.95, -0.16, I² = 90%). RAASi were superior to placebo in reducing the risks of kidney failure (OR = 0.74; 95%CI: 0.56, 0.97) and doubling of serum creatinine levels (SrCr; OR = 0.71; 95%CI: 0.55, 0.91), but not in promoting the regression of albuminuria (OR = 3.00; 95%CI: 0.96, 9.37). RAASi, however, were not superior to other antihypertensives in reducing the risks of these outcomes. Patients with type 2 diabetes, macroalbuminuria and longer duration of diabetes had less risk of developing kidney failure in placebo-controlled trials, while longer duration of diabetes, normal kidney function, and hypertension increased the probability of achieving regression of albuminuria in active-controlled trials.

Conclusion

While our findings revealed the non-superiority of RAASi over other antihypertensives and portrayed a class effect on several subgroups of study participants, it raised a challenging question on whether RAASi deserve their place as first-line therapy in managing diabetic nephropathy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-022-02763-1.

Production of Dual Inhibitory Hydrolysate by Enzymatic Hydrolysis of Squid Processing By-product

Squid processing by-product contains unutilized abundant proteins. In this study, 6 proteases (pepsin, protamex, trypsin, neutral protease, alkaline protease, and papain) were firstly employed to hydrolyze the squid processing by-product protein. The neutral protease-digested hydrolysate was found to have the most promising ACE (angiotensin-converting enzyme) inhibitory activity. Based on Box-Behnken design, the optimal hydrolysis process was determined to be: 52.4 ℃ of temperature, 5.7 h of time, pH 7.1, and 8151 U/g of enzyme. Under these conditions, the ACE inhibition rate and polypeptide content of the hydrolysate were 84.26% and 229.09 mg/g, respectively. Subsequently, ultrafiltration was performed, and the ACE and renin inhibitory activities of the filtrate (< 1 kDa) were the highest, reaching 87.48 ± 1.76% and 69.72 ± 1.16%, with IC₅₀ values of 1.34 ± 0.12 mg/mL and 1.47 ± 0.06 mg/mL, respectively. However, these activities decreased to 35.15 ± 1.31% and 43.17% ± 1.42%, respectively, after digestion by simulated gastrointestinal juice. Nevertheless, this is the first report representing the neutral protease-digested hydrolysate of squid processing by-product as a potential source of both ACE and renin inhibitors.

High Prevalence of Autonomous Aldosterone Production in Hypertension: How to Identify and Treat It

PURPOSE OF REVIEW

Primary aldosteronism (PA) affects millions of individuals worldwide. When unrecognized, PA leads to cardiovascular and renal complications via mechanisms independent from those mediated by hypertension. In this review, we emphasize the importance of PA screening in at-risk populations, and we provide options for customized PA therapy, with consideration for a variety of clinical care settings.

RECENT FINDINGS

Compelling evidence puts PA at the forefront of secondary hypertension etiologies. Cardiovascular and renal damage likely begins in early stages of renin-independent aldosterone excess. PA must be considered not only in patients with resistant hypertension or hypokalemia, but also when hypertension is associated with obstructive sleep apnea or atrial fibrillation, or in those with early-onset hypertension. Screening with plasma aldosterone and renin is widely accessible, and targeted PA therapy can successfully circumvent the excess cardiorenal risk relative to equivalent primary hypertension. Identifying and treating PA in early stages provide opportunities for personalized hypertension therapy in a large number of patients. Additionally, early targeted therapy of PA is essential for pivoting the care of such patients from reactive to preventive of cardiovascular and renal morbidity and mortality.

Unraveling the Differentially Articulated Axes of the Century-Old Renin-Angiotensin-Aldosterone System: Potential Therapeutic Implications

Among numerous choices in cardiovascular therapies used for the management of hypertension and heart failure, drugs affecting the renin-angiotensin-aldosterone system (RAAS) hold substantial therapeutic roles. Therapies aimed at modifying the RAAS and its overactivation are employed for the management of various insidious disorders. In the pharmacologic perspective, RAAS is one of the frequently manipulated systems for the management of hypertension, heart failure, myocardial infarction, and renal disease. The RAAS pharmacologic interventions principally include the ACE inhibitors, the angiotensin II-AT1 receptor blockers, the mineralocorticoid receptor antagonists, and the direct renin inhibitors. In addition, therapeutic implication of ACE2/angiotensin (1-7)/Mas receptor activation using various ligands is being explored owing to their anti-inflammatory, anti-fibrotic, vasodilatory, and cardiovascular defensive roles. Moreover, being considered as the counter-regulatory arm of AT1 receptor, the potential role of AT2 receptor activation using selective AT2 receptor agonist is currently investigated for its efficacy in pulmonary complications. As an important regulator of fluid volume, blood pressure, and cardiovascular-renal function, the RAAS has been documented as a diversified intricate system with several therapeutic possibilities coupled with their fundamental structural and functional modulatory roles in cardiovascular, renal, and other systems. The RAAS possesses a number of regulatory, deregulatory, and counter-regulatory axes of physiopathologic importance in health and disease. The counter-regulatory arms of the RAAS might play an essential role in mitigating cardiovascular, renal, and pulmonary pathologies. In light of this background, we sought to explore the classical and counter-regulatory axes/arms of the RAAS and their imperative roles in physiologic functions and disease pathogenesis.

Magnetic casein aggregates as an innovative support platform for laccase immobilization and bioremoval of crystal violet

In this study, casein@CoFe₂O₄ was fabricated through a green synthesis methodology and applied to immobilize laccase. The constructed casein@CoFe₂O₄ exhibited porous structures with distinct cavities and suitable magnetic properties. The abundance of aromatic functional groups on the surface renneted casein and possible π-type interaction between laccase and para-κ-casein resulted in a successful immobilization. The biocatalyst retained 50% of its initial activity after 24 reusability cycles, indicating stable immobilization of laccase onto the casein microstructures. The stability of laccase after immobilization was improved by 300% in comparison with the free enzyme, especially in basic pH values. The constructed laccase@casein@CoFe₂O₄ was then incorporated to remove crystal violet (CV) as an environmentally harmful synthetic tri-phenylmethane dye. The prepared heterogeneous biocatalyst effectively diminished the antimicrobial activity of CV up to 81.3% in 40 min against some bacterial strains, resulting from the formation of more minor toxic metabolites identified by liquid chromatography coupled with mass spectroscopy after degradation procedure. The proposed green and feasible method for the preparation of magnetic casein aggregates has not been previously reported. The incorporation of casein, which acted as a molecular chaperon, resulted in a significant improvement in the enzymatic stability and exhibited appropriate reusability for the constructed biocatalytic system.

Renin-angiotensin system: Basic and clinical aspects-A general perspective

The renin–angiotensin system (RAS) is one of the most complex hormonal regulatory systems, involving several organs that interact to regulate multiple body functions. The study of this system initially focused on investigating its role in the regulation of both cardiovascular function and related pathologies. From this approach, pharmacological strategies were developed for the treatment of cardiovascular diseases. However, new findings in recent decades have suggested that the RAS is much more complex and comprises two subsystems, the classic RAS and an alternative RAS, with antagonistic effects that are usually in equilibrium. The classic system is involved in pathologies where inflammatory, hypertrophic and fibrotic phenomena are common and is related to the development of chronic diseases that affect various body systems. This understanding has been reinforced by the evidence that local renin–angiotensin systems exist in many tissue types and by the role of the RAS in the spread and severity of COVID-19 infection, where it was discovered that viral entry into cells of the respiratory system is accomplished through binding to angiotensin-converting enzyme 2, which is present in the alveolar epithelium and is overexpressed in patients with chronic cardiometabolic diseases. In this narrative review, preclinical and clinical aspects of the RAS are presented and topics for future research are discussed some aspects are raised that should be clarified in the future and that call for further investigation of this system.

Effects of mineralocorticoid receptor antagonists on sex hormones and body composition in patients with primary aldosteronism

Mineralocorticoid receptor antagonists are frequently used for the treatment of primary aldosteronism. Steroidal mineralocorticoid receptor antagonists may have antagonistic actions on androgen receptors, agonistic actions on progesterone receptors, and antagonistic actions on mineralocorticoid receptors. Because anti-androgen effects may cause body fat accumulation and skeletal muscle atrophy, there are concerns that this drug may have adverse effects on body composition. Therefore, in this randomized prospective study, we compared the adverse effects of spironolactone, a steroidal mineralocorticoid receptor antagonist, and esaxerenone, a nonsteroidal mineralocorticoid receptor antagonist, on sex hormone levels and body composition in patients with primary aldosteronism without severe renal dysfunction. The serum concentration of free testosterone was significantly higher in the spironolactone group than in the esaxerenone group in both males and females. However, the levels of estradiol, progesterone, luteinizing hormone, and follicle stimulating hormone did not significantly increase. Changes in body fat percentage and muscle mass rate were not significantly different between the two groups. No patient showed a serum potassium level ≥6.0 mEq/L; however, serum potassium levels were significantly higher in the spironolactone group than in the esaxerenone group. These data indicate that spironolactone may have antagonistic effects on androgen receptors. Esaxerenone did not show any apparent adverse effects, suggesting that it can be safely used in patients with primary aldosteronism.

Distinct renin/aldosterone activity profiles correlate with renal function, natriuretic response, decongestive ability and prognosis in acute heart failure

BACKGROUND

Although renin-angiotensin-aldosterone system (RAAS) activation is believed to be the major driver of acute heart failure (AHF) episodes our understanding of its prevalence and clinical relevance in contemporary settings is incomplete.

METHODS

Serum renin and aldosterone were measured at day-1 and at discharge in patients (n = 211) that were hospitalized between 2016 and 2017 for AHF in a single cardiology center. The population was profiled based on upper limits of normal (ULN) of both biomarkers assessed at day-1 and linked with the clinical course and outcomes.

RESULTS

The study population constituted of three profiles: RAAS-/- (n = 121 [57%]); RAAS+/- (n = 60 [28%]); and RAAS+/+ (n = 30 [14%]). The RAAS+/+ profile had the lowest blood pressure and serum sodium at admission, day-2 and discharge compared to the other profiles (p < 0.001). The RAAS+/+ patients had significantly lower urine Na+ at admission (57.8 ± 36.7 vs 97.3 ± 31.3 and 86.4 ± 35.0), day-1 (52.7 ± 32.7 vs 85.3 ± 36.3 and 75.5 ± 33.9) mmol/l, vs RAAS-/- and RAAS+/- profiles, respectively, all p < 0.001. There was also a gradual decrease of renal function across increasing RAAS profiles. The RAAS+/+ profile received higher dose of furosemide at discharge 120 [80-160] vs the other profiles 80 [40-120] mg, p < 0.01. The risks of one year mortality or HF rehospitalization increased across the RAAS profiles (p < 0.001). The trajectory of renin or aldosterone change during hospitalization was not related to outcomes.

CONCLUSIONS

The RAAS overactivity is not essential for development of AHF. However, elevated RAAS is a marker of more advanced stages of heart failure, is related to low natriuresis and adverse clinical outcomes.

[Conn's syndrome-Frequent and still too rarely diagnosed to underdiagnosed]

Conn's syndrome represents the most common cause of endocrine hypertension and is associated with an increased cardiovascular risk, a series of comorbidities (including type 2 diabetes mellitus) and with their frequent occurrence. Therefore, a correct and rapid diagnosis is of essential importance. Measurement of the aldosterone-renin ratio is used as a first screening test for primary aldosteronism. This should ideally be evaluated under optimized conditions (e.g. at rest), after adjustment of the blood pressure medication and with an equilibrated potassium balance. In cases of elevated aldosterone to renin ratio, further confirmatory testing as well as imaging of the adrenal glands is needed. After confirmation of Conn's syndrome a differentiation between a unilateral and bilateral adrenal disease is necessary for further treatment planning. The current gold standard is still selective adrenal vein catheterization. Promising alternatives to an adrenal vein catheter, such as functional imaging techniques and measurement of steroid profiles are currently being investigated in clinical trials. In cases of lateralization of aldosterone production, unilateral laparoscopic adrenalectomy of the affected side is the treatment of choice. In contrast, patients with bilateral disease or patients with contraindications for adrenalectomy should receive life-long treatment with mineralocorticoid receptor antagonists.