Comparison between screening for primary aldosteronism with and without drug adjustment.

OBJECTIVE: Few studies have evaluated the performance of non-drug-adjusted primary aldosteronism (PA) screening. Therefore, we aimed to examine the consistency between PA screening results with and without drug adjustment and to explore the effectiveness of screening without drug adjustment. METHODS: This prospective study included 650 consecutive patients with a high risk of incidence PA. Patients who initially screened positive underwent rescreening with drug adjustments and confirmatory tests. Regarding the remaining patients, one of every three consecutive patients underwent rescreening with drug adjustments and confirmatory tests. The changes in aldosterone and renin concentrations were compared between patients with essential hypertension (EH) and those with PA before and after drug adjustment. Sensitivity and specificity were used to assess the diagnostic performance of screening without drug adjustment, using the confirmatory test results as the reference. RESULTS: We screened 650 patients with hypertension for PA. Forty-nine patients were diagnosed with PA and 195 with EH. Regarding drugs, 519 patients were taking angiotensin-converting enzyme inhibitors (ACEIs), angiotensin II receptor blockers (ARBs), calcium channel blockers (CCBs), or diuretics alone or in combination. Forty-one patients were taking beta-blockers. Ninety patients were taking beta-blockers in combination with other drugs. In patients treated with ACEIs, ARBs, CCBs, or diuretics alone, or in combination, or beta-blockers alone, PA positivity was determined using the criteria, aldosterone-to-renin ratio (ARR) >38 pg/mL/pg/mL and plasma aldosterone concentration (PAC) >100 pg/mL, and negativity, using the criteria, ARR <9 pg/mL/pg/mL; the sensitivity and specificity were 94.7% and 94.5%, respectively. After drug adjustment, the sensitivity and specificity of screening were 92.1% and 89%, respectively. CONCLUSIONS: In patients not treated with beta-blockers combined with others, when ARR >38 pg/mL/pg/mL and plasma aldosterone concentration (PAC) >100 pg/mL, or, ARR <9 pg/mL/pg/mL, non-drug-adjusted screening results were identical to with drug adjustment. Non-drug-adjusted screening could reduce the chance of medication adjustment, enable patients to continue their treatments and avoiding adverse effects, is of clinical importance.

Primary aldosteronism (PA) is the most common form of endocrine hypertension. The risk of stroke, myocardial infarction, heart failure, atrial fibrillation, and deterioration of kidney function is higher in PA than in essential hypertension (EH), even with the same blood pressure (BP) levels. However, many patients remain undiagnosed because most antihypertensive drugs substantially interfere with PA screening results, which makes drug adjustment necessary. This can be a time-consuming and unsafe process, requiring 4­6 weeks, and could lead to a hypertensive crisis and other complications. Some studies have suggested that certain antihypertensive drugs can be continued during PR screening. However, few studies have evaluated the performance of non-drug-adjusted PA screening. Therefore, in this prospective study, we aimed to compare patients with hypertension and a high risk of PA before and after drug adjustment and to use confirmatory test results as a reference to explore the diagnostic or exclusion effect. We found that non-drug-adjusted screening performs similarly to drug-adjusted screening in a particular group of patients. Our findings could aid in preventing unnecessary drug adjustment for PA screening, thereby reducing the risk in these patients.

Integrated metabolomics analysis reveals mechanistic insights into variability in blood pressure response to thiazide diuretics and beta blockers.

Hypertensive patients with a higher proportion of genetic West African ancestry (%GWAA) have better blood pressure (BP) response to thiazide diuretics (TDs) and worse response to ß-blockers (BBs) than those with lower %GWAA, associated with their lower plasma renin activity (PRA). TDs and BBs are suggested to reduce BP in the long term through vasodilation via incompletely understood mechanisms. This study aimed at identifying pathways underlying ancestral differences in PRA, which might reflect pathways underlying BP-lowering mechanisms of TDs and BBs. Among hypertensive participants enrolled in the Pharmacogenomics Evaluation of Antihypertensive Responses (PEAR) and PEAR-2 trials, we previously identified 8 metabolites associated with baseline PRA and 4 metabolic clusters (including 39 metabolites) that are different between those with GWAA <45% versus ≥45%. In the current study, using Ingenuity Pathway Analysis (IPA), we integrated these signals. Three overlapping metabolic signals within three significantly enriched pathways were identified as associated with both PRA and %GWAA: ceramide signaling, sphingosine 1- phosphate signaling, and endothelial nitric oxide synthase signaling. Literature indicates that the identified pathways are involved in the regulation of the Rho kinase cascade, production of the vasoactive agents nitric oxide, prostacyclin, thromboxane A2, and endothelin 1; the pathways proposed to underlie TD- and BB-induced vasodilatation. These findings may improve our understanding of the BP-lowering mechanisms of TDs and BBs. This might provide a possible step forward in personalizing antihypertensive therapy by identifying patients expected to have robust BP-lowering effects from these drugs.

Commensal microbiota regulate aldosterone.

The gut microbiome regulates many important host physiological processes associated with cardiovascular health and disease; however, the impact of the gut microbiome on aldosterone is unclear. Investigating whether gut microbiota regulate aldosterone can offer novel insights into how the microbiome affects blood pressure. In this study, we aimed to determine whether gut microbiota regulate host aldosterone. We used enzyme-linked immunosorbent assays (ELISAs) to assess plasma aldosterone and plasma renin activity (PRA) in female and male mice in which gut microbiota are intact, suppressed, or absent. In addition, we examined urinary aldosterone. Our findings demonstrated that when the gut microbiota is suppressed following antibiotic treatment, there is an increase in plasma and urinary aldosterone in both female and male mice. In contrast, an increase in PRA is seen only in males. We also found that when gut microbiota are absent (germ-free mice), plasma aldosterone is significantly increased compared with conventional animals (in both females and males), but PRA is not. Understanding how gut microbiota influence aldosterone levels could provide valuable insights into the development and treatment of hypertension and/or primary aldosteronism. This knowledge may open new avenues for therapeutic interventions, such as probiotics or dietary modifications to help regulate blood pressure via microbiota-based changes to aldosterone.NEW & NOTEWORTHY We explore the role of the gut microbiome in regulating aldosterone, a hormone closely linked to blood pressure and cardiovascular disease. Despite the recognized importance of the gut microbiome in host physiology, the relationship with circulating aldosterone remains largely unexplored. We demonstrate that suppression of gut microbiota leads to increased levels of plasma and urinary aldosterone. These findings underscore the potential of the gut microbiota to influence aldosterone regulation, suggesting new possibilities for treating hypertension.

Association of left ventricular diastolic dysfunction with inflammatory activity, renal dysfunction, and liver-related mortality in patients with cirrhosis and ascites.

Left ventricular diastolic dysfunction (LVDD) is the predominant cardiac abnormality in cirrhosis. We investigated the association of LVDD with systemic inflammation and its impact on renal function, occurrence of hepatorenal syndrome (HRS) and survival in patients with cirrhosis and ascites. We prospectively enrolled 215 patients with cirrhosis and ascites. We evaluated the diagnosis and grading of LVDD by Doppler echocardiography, inflammatory markers, systemic hemodynamics, vasoactive factors, radioisotope-assessed renal function and blood flow, HRS development and liver-related mortality. LVDD was diagnosed in 142 (66%) patients [grade 2/3: n  = 61 (43%)]. Serum lipopolysaccharide-binding protein (LBP), plasma renin activity (PRA) and glomerular filtration rate (GFR) were independently associated with the presence of grade 2/3 LVDD and the severity of diastolic dysfunction. Serum tumor necrosis factor-α, cardiac output and plasma noradrenaline were also independently associated with the presence of grade 2/3 LVDD. The diastolic function marker E / e ' was strongly correlated with serum LBP ( r  = 0.731; P  < 0.001), PRA ( r  = 0.714; P  < 0.001) and GFR ( r  = -0.609; P  < 0.001) among patients with LVDD. The 5-year risk of HRS development and death was significantly higher in patients with grade 2/3 LVDD compared to those with grade 1 (35.5 vs. 14.4%; P  = 0.01 and 53.3 vs. 28.2%; P  = 0.03, respectively). The occurrence and severity of LVDD in patients with cirrhosis and ascites is closely related to inflammatory activity. Advanced LVDD is associated with baseline circulatory and renal dysfunction, favoring HRS development, and increased mortality.

Gender Differences in Cardiac Organ Damage in Arterial Hypertension: Assessing the Role of Drug Nonadherence.

INTRODUCTION: Cardiac organ damage like left ventricular (LV) hypertrophy and left atrial (LA) enlargement is more prevalent in women than men with hypertension, but the mechanisms underlying this gender difference remain unclear. METHODS: We tested the association of drug nonadherence with the presence of LV hypertrophy and LA enlargement by echocardiography in 186 women and 337 men with uncontrolled hypertension defined as daytime systolic blood pressure (BP) ≥ 135mmHg despite the prescription of at least two antihypertensive drugs. Drug adherence was assessed by measurements of serum drug concentrations interpreted by an experienced pharmacologist. Aldosterone-renin-ratio (ARR) was measured on actual medication. RESULTS: Women had a higher prevalence of LV hypertrophy (46% vs. 33%) and LA enlargement (79% vs 65%, both p < 0.05) than men, while drug nonadherence (8% vs. 9%, p > 0.514) did not differ. Women were older and had lower serum renin concentration and higher ARR than men, while 24-h systolic BP (141 ± 9 mmHg vs. 142 ± 9 mmHg), and the prevalences of obesity (43% vs. 50%) did not differ (all p > 0.10). In multivariable analyses, female gender was independently associated with a two-fold increased risk of LV hypertrophy (OR 2.01[95% CI 1.30-3.10], p = 0.002) and LA enlargement (OR 1.90 [95% CI 1.17-3.10], p = 0.010), while no association with drug nonadherence was found. Higher ARR was independently associated with LV hypertrophy in men only (OR 2.12 [95% CI 1.12-4.00] p = 0.02). CONCLUSIONS: Among patients with uncontrolled hypertension, the higher prevalence of LV hypertrophy and LA enlargement in women was not explained by differences in drug nonadherence. REGISTRATION: URL:  https://www. CLINICALTRIALS: gov ; Unique identifier: NCT03209154.

Excess renin is attributed to the combination of forward and backward failure in HFrEF.

AIMS: Regulation of the renin-angiotensin system (RAS) in heart failure (HF) with reduced ejection fraction (HFrEF) still raises questions, as a large proportion of patients show normal renin levels despite manifest disease. Experimental venous congestion results in reduced renal perfusion pressure and stimulates renin secretion. We hypothesized that excess renin levels are mainly a result of right ventricular failure as a sequalae of left ventricular dysfunction. The study aimed to link right ventricular function (RVF) with renin levels and to investigate further contributors to excess RAS activation. METHODS AND RESULTS: Three hundred thirty-two chronic HFrEF patients undergoing routine ambulatory care were consecutively enrolled in a prospective, registry-based, observational study. Laboratory parameters, including cardiac-specific markers renin, aldosterone, and N-terminal pro-brain natriuretic peptide (NT-proBNP), echocardiographic examination (n = 247), and right heart catheterization (n = 85), were documented. The relationship between renin and its respective parameters was analysed. Renin concentration was not associated with the New York Heart Association class or NT-proBNP. Systolic blood pressure, systemic vascular resistance, serum sodium, aldosterone, and lactate dehydrogenase were associated with increased renin levels (P < 0.035 for all). Renin levels similarly increased with worsening of RVF parameters such as fractional area change, tricuspid annular plane systolic excursion, tissue Doppler imaging, and inferior vena cava diameter (P < 0.011 for all), but not with pulmonary pressure. Excess renin levels were observed when worsening RVF was combined with reduced renal perfusion {625 µIU/mL [interquartile range (IQR): 182-1761] vs. 67 µIU/mL [IQR: 16-231], P < 0.001}, which was associated with worse survival. CONCLUSIONS: While unrelated to classical indices of HF severity, circulating renin levels increase with the worsening of RVF, especially in the combined presence of forward and backward failure. This might explain normal renin levels in HFrEF patients but also excess renin levels in poor haemodynamic conditions.

Dysfunction of the renin-angiotensin-aldosterone system in human septic shock.

Sepsis and septic shock are global healthcare problems associated with mortality rates of up to 40% despite optimal standard-of-care therapy and constitute the primary cause of death in intensive care units worldwide. Circulating biomarkers of septic shock severity may represent a clinically relevant approach to individualize those patients at risk for worse outcomes early in the course of the disease, which may facilitate early and more precise interventions to improve the clinical course. However, currently used septic shock biomarkers, including lactate, may be non-specific and have variable impact on prognosis and/or disease management. Activation of the renin-angiotensin-aldosterone system (RAAS) is likely an early event in septic shock, and studies suggest that an elevated level of renin, the early and committed step in the RAAS cascade, is a better predictor of worse outcomes in septic shock, including mortality, than the current standard-of-care measure of lactate. Despite a robust increase in renin, other elements of the RAAS, including endogenous levels of Ang II, may fail to sufficiently increase to maintain blood pressure, tissue perfusion, and protective immune responses in septic shock patients. We review the current clinical literature regarding the dysfunction of the RAAS in septic shock and potential therapeutic approaches to improve clinical outcomes.

Subtype Identification of Surgically Curable Primary Aldosteronism During Treatment With Mineralocorticoid Receptor Blockade.

BACKGROUND: Current guidelines and consensus documents recommend withdrawal of mineralocorticoid receptor antagonists (MRAs) before primary aldosteronism (PA) subtyping by adrenal vein sampling (AVS), but this practice can cause severe hypokalemia and uncontrolled high blood pressure. Our aim was to investigate if unilateral PA can be identified by AVS during MRA treatment. METHODS: We compared the rate of unilateral PA identification between patients with and without MRA treatment in large data sets of patients submitted to AVS while off renin-angiotensin system blockers and ß-blockers. In sensitivity analyses, the between-group differences of lateralization index values after propensity score matching and the rate of unilateral PA identification in subgroups with undetectable (≤2 mUI/L), suppressed (<8.2 mUI/L), and unsuppressed (≥8.2 mUI/L) direct renin concentration levels were also evaluated. RESULTS: Plasma aldosterone concentration, direct renin concentration, and blood pressure values were similar in non-MRA-treated (n=779) and MRA-treated (n=61) patients with PA, but the latter required more antihypertensive agents (P=0.001) and showed a higher rate of adrenal nodules (82% versus 67%; P=0.022) and adrenalectomy (72% versus 54%; P=0.01). However, they exhibited no significant differences in commonly used AVS indices and the area under the receiving operating characteristic curve of lateralization index, both under unstimulated conditions and postcosyntropin. Several sensitivity analyses confirmed these results in propensity score matching adjusted models and in patients with undetectable, or suppressed or unsuppressed renin levels. CONCLUSIONS: At doses that controlled blood pressure and potassium levels, MRAs did not preclude the identification of unilateral PA at AVS. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01234220.

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.

Prediction of endogenous mineralocorticoid receptor activity by depressor effects of mineralocorticoid receptor antagonists in patients with primary aldosteronism.

Patients with primary aldosteronism have an increased risk of developing cardiovascular disease. The response to mineralocorticoid receptor antagonists varies among individuals, indicating diverse mineralocorticoid receptor activities in these patients. This study explored the factors linked to the efficacy of blood pressure reduction through mineralocorticoid receptor antagonists in patients with primary aldosteronism. We examined the relationship between the reduction in blood pressure and patient characteristics in a group of 41 patients with primary aldosteronism (24 males, mean age 55 ± 13 years, including 34 patients diagnosed with bilateral primary aldosteronism) before and after undergoing treatment with mineralocorticoid receptor antagonists. Significant reductions in office blood pressure were observed 3 and 6 months after treatment initiation. Single correlation analyses showed that the urinary chloride-to-potassium ratio displayed the strongest positive association with blood pressure reduction, surpassing plasma aldosterone concentration, plasma renin activity, and urinary sodium-to-potassium ratio, at 3 and 6 months. Multiple correlation analyses revealed a consistent and independent positive correlation between the urinary chloride-to-potassium ratio and blood pressure reduction at 3 and 6 months. The optimal threshold for the urinary chloride-to-potassium ratio with respect to its ability to lower blood pressure, was determined as 3.18. These results imply that the urinary chloride-to-potassium ratio may be independently associated with the effectiveness of blood pressure reduction facilitated by mineralocorticoid receptor antagonists. Moreover, it could potentially serve as a valuable predictor of the effectiveness of these agents and function as an indicator of endogenous mineralocorticoid receptor activity in patients with primary aldosteronism.

Investigating the cut-off values of captopril challenge test for primary aldosteronism using the novel chemiluminescent enzyme immunoassay method: a retrospective cohort study.

The measurement evolution enabled more accurate evaluation of aldosterone production in hypertensive patients. However, the cut-off values for novel assays have been not sufficiently validated. The present study was undertaken to validate the novel chemiluminescent enzyme immunoassay for aldosterone in conjunction with other methods. Moreover, we also aimed to establish a new cut-off value for primary aldosteronism in the captopril challenge test using the novel assay. First, we collected 390 plasma samples, in which aldosterone levels measured using liquid chromatography-mass spectrometry ranged between 0.18 and 1346 ng/dL. The novel chemiluminescent enzyme immunoassay showed identical correlation of plasma aldosterone with liquid chromatography-mass spectrometry, in contrast to conventional radioimmunoassay. Further, we enrolled 299 and 39 patients with primary aldosteronism and essential hypertension, respectively. Plasma aldosterone concentrations measured using the novel assay were lower than those measured by radioimmunoassay, which resulted in decreased aldosterone-to-renin ratios. Subsequently, positive results of the captopril challenge test based on radioimmunoassay turned into "negative" based on the novel assay in 45% patients with primary aldosteronism, using the conventional cut-off value (aldosterone-to-renin activity ratio > 20 ng/dL per ng/mL/h). Receiver operating characteristic curve analysis demonstrated that aldosterone-to-renin activity ratios > 8.2 ng/dL per ng/mL/h in the novel assay was compatible with the conventional diagnosis (sensitivity, 0.874; specificity, 0.980). Our study indicates the great measurement accuracy of the novel chemiluminescent enzyme immunoassay for aldosterone, and the importance of measurement-adjusted cut-offs in the diagnosis of primary aldosteronism.

A 120-Minute Saline Infusion Test for the Confirmation of Primary Aldosteronism: A Pilot Study.

BACKGROUND: The saline infusion test (SIT) to confirm primary aldosteronism requires infusing 2 L of normal saline over 240 minutes. Previous studies raised concerns regarding increased blood pressure and worsening hypokalemia during SIT. We aimed to evaluate the diagnostic applicability of a SIT that requires 1 L of saline infusion over 120 minutes. METHODS: A cross-sectional study, including all patients in a large medical center who underwent SIT from 1 January 2015 to 30 April 2023. Blood samples were drawn for baseline renin and aldosterone (t = 0) after 2 hours (t = 120 min) and after 4 hours (t = 240 min) of saline infusion. We used ROC analysis to evaluate the sensitivity and specificity of various aldosterone cut-off values at t = 120 to confirm primary aldosteronism. RESULTS: The final analysis included 62 patients. A ROC analysis yielded 97% specificity and 90% sensitivity for a plasma aldosterone concentration (PAC) of 397 pmol/L (14 ng/dL) at t = 120 to confirm primary aldosteronism, and an area under the curve of 0.97 (95% CI [0.93, 1.00], P < 0.001). Almost half (44%) of the patients did not suppress PAC below 397 pmol/L (14 ng/dL) at t = 120. Of them, only one (4%) patient suppressed PAC below 276 pmol/L (10 ng/dL) at t = 240. Mean systolic blood pressure increased from 140.1 ±â€…21.3 mm Hg at t = 0 to 147.6 ±â€…14.5 mm Hg at t = 240 (P = 0.011). CONCLUSIONS: A PAC of 397 pmol/L (14 ng/dL) at t = 120 has high sensitivity and specificity for primary aldosteronism confirmation.

Reverse Phenotypes of Patients with Genetically Confirmed Liddle Syndrome.

BACKGROUND: Liddle syndrome was initially characterized by hypertension, hypokalemia, metabolic alkalosis, and suppressed plasma renin and aldosterone, resulting from gain-of-function variants in the epithelial Na + channel (ENaC). Efficient treatment with ENaC inhibitors is available, but the phenotypic spectrum of genetically confirmed Liddle syndrome is unknown, and some patients may remain undiagnosed and at risk of inefficient treatment. In this study, we used a reverse phenotyping approach to investigate the Liddle syndrome phenotypic spectrum and genotype-phenotype correlations. METHODS: Pubmed, Embase, Scopus, and the Human Gene Mutation Database were searched for articles reporting Liddle syndrome variants. The genetic variants were systematically classified to identify patients with genetically confirmed Liddle syndrome. We identified 62 articles describing 45 unique variants within 86 Liddle syndrome families, and phenotypic data were pooled for 268 patients with confirmed Liddle syndrome. RESULTS: The Liddle syndrome variants localized to exon 13 of SCNN1B and SCNN1G , disrupting the PPPxY motif critical for downregulating ENaC activity. Hypertension sensitive to ENaC inhibition was present in 97% of adults carrying Liddle syndrome variants while hypokalemia, metabolic alkalosis, and plasma renin and aldosterone suppression showed incomplete penetrance. In addition, 95% and 55% of patients had a family history of hypertension or cerebrovascular events, respectively. The genotype had minor phenotypic effects; however, probands compared with relatives showed significant phenotypic discrepancies consistent with selection bias for initial genetic screening. CONCLUSIONS: Patients with genetically confirmed Liddle syndrome displayed a phenotypic spectrum, with ENaC-sensitive hypertension and family history of hypertension being the most common features. The phenotype seemed independent of the specific gene or variant type involved.

The Clinical Impact of Sample Storage at -20†°C on Renin Reference Intervals and Aldosterone-Renin Ratio Calculations.

Cryoactivation is known to occur in whole blood and plasma samples when kept between +4 and -5 °C, leading to falsely high renin concentrations. In 2022 it has been clearly shown that cryoactivation can also occur in samples stored at -20 °C. Based on these new findings, here we discuss how this can influence the clinical diagnosis of patients. First, we show that storage of renin plasma samples can affect the renin measurements and thereby the aldosterone to renin ratio (ARR) calculation, which might explain the high intraindividual variability in ARR also recently demonstrated. Second, we discuss the existing studies on the establishment of renin reference intervals and note the lack of attention given to this recently revealed preanalytical condition. Our literature review of the reference intervals for renin suggest that cryoactivation might have influenced the published data.

Neurohormonal Activation and Renal Chloride Avidity in Acute Heart Failure: Clinical Evidence Supporting the "Chloride Theory".

INTRODUCTION: Heart failure (HF) progression according to changes in the serum chloride concentration ([sCl-]) was recently proposed as the "chloride (Cl) theory" for HF pathophysiology. The present study examined the association of neurohormones and renal Cl avidity to determine their contribution to acute HF and their involvement to the "Cl theory." METHODS: Data from 29 patients with acute HF (48% men; 80.3 ± 12 years) were analyzed. Blood and urine samples were obtained before decongestive therapy. Clinical tests included peripheral blood, serum and spot urinary electrolytes, b-type natriuretic peptide (BNP), and plasma neurohormones. RESULTS: In the 29 patients, urinary Cl concentrations ([uCl-]) inversely correlated with log (plasma renin activity [PRA]) (r = -0.64, p = 0.0002) and log (plasma aldosterone concentration) (r = -0.50, p = 0.006). The [sCl-]‒[uCl-] difference positively correlated with log PRA (r = 0.63, p = 0.0002) and log (plasma aldosterone concentration) (r = 0.49, p = 0.008). Patients were divided into 2 groups according to the [sCl-]‒[uCl-] difference, an excretion (low renal Cl avidity) group and an absorption (high renal Cl avidity) group. Compared with the excretion group (-77 to ‒5 mEq/L; n = 14), the absorption group (1-84 mEq/L; n = 15) exhibited greater renal impairment (serum creatinine; 1.45 ± 0.63 vs. 1.00 ± 0.38 mg/d, p = 0.029) and cardiac burden (log BNP; 2.99 ± 0.3 vs. 2.66 ± 0.32 pg/mL, p = 0.008), higher log PRA (0.20 ± 0.58 vs. -0.25 ± 0.35 ng/mL/h, p = 0.018), and lower fractional urinary Cl excretion (1.34 ± 1.3 vs. 5.33 ± 4.1%, p < 0.001). CONCLUSION: Renal Cl avidity differs in acute HF, i.e., excretion (low renal Cl avidity) versus absorption (high renal Cl avidity) types, involving renin-aldosterone-angiotensin activity as the underlying mechanism, which provides the neurohormonal background for the "Cl theory." A version of this study was presented in part at the annual international scientific assembly (ACC.23) of the American College of Cardiology, March 4-6, 2023.

Renin and renin blockade have no role in complement activity.

Renin, an aspartate protease, regulates the renin-angiotensin system by cleaving its only known substrate angiotensinogen to angiotensin. Recent studies have suggested that renin may also cleave complement component C3 to activate complement or contribute to its dysregulation. Typically, C3 is cleaved by C3 convertase, a serine protease that uses the hydroxyl group of a serine residue as a nucleophile. Here, we provide seven lines of evidence to show that renin does not cleave C3. First, there is no association between renin plasma levels and C3 levels in patients with C3 Glomerulopathies (C3G) and atypical Hemolytic Uremic Syndrome (aHUS), implying that serum C3 consumption is not increased in the presence of high renin. Second, in vitro tests of C3 conversion to C3b do not detect differences when sera from patients with high renin levels are compared to sera from patients with normal/low renin levels. Third, aliskiren, a renin inhibitor, does not block abnormal complement activity introduced by nephritic factors in the fluid phase. Fourth, aliskiren does not block dysregulated complement activity on cell surfaces. Fifth, recombinant renin from different sources does not cleave C3 even after 24 hours of incubation at 37 °C. Sixth, direct spiking of recombinant renin into sera samples of patients with C3G and aHUS does not enhance complement activity in either the fluid phase or on cell surfaces. And seventh, molecular modeling and docking place C3 in the active site of renin in a position that is not consistent with a productive ground state complex for catalytic hydrolysis. Thus, our study does not support a role for renin in the activation of complement.

A longitudinal study on the effect of obesity upon circulating renin-angiotensin system in normal pregnancy.

BACKGROUND AND AIMS: Obesity is the most common health issue in women of reproductive age, which profoundly affects maternal-fetal health. Despite progress in understanding key inflammatory and metabolic changes, the pathogenesis of the cardiovascular phenotype of obese pregnant women remains to be fully understood. This study aimed at: (i) evaluating the changes of the renin-angiotensin system (RAS) throughout pregnancy in obese vs normal weight (control) women, and (ii) evaluating the presence of any associations between maternal hemodynamic status and RAS changes. METHODS AND RESULTS: Thirty-eight normal weight and nineteen obese pregnant women were included. Clinical assessment, blood samples and maternal hemodynamic evaluation were performed at 12, 20, 30, and 36 weeks, while ultrasound assessment was scheduled at 20, 30, and 36 weeks of gestation. Measurements of sFlt-1, PlGF, Angiotensinogen, Renin, AngII, Ang1-7, ACE and ACE2 were performed by ELISA. Our data show that normotensive obese women had lower placental blood supply, as assessed by UV-Q and UV-Q/EFW, as compared to controls, and significantly higher levels of AngII and AngII/Ang1-7 ratio, which were inversely related to placental blood supply. CONCLUSIONS: Our study shows for the first time that normotensive obese women exhibited a significant progressive increase of AngII and AngII/Ang1-7 throughout pregnancy, which were inversely related to placental blood supply as assessed by UV-Q and UV-Q/EFW. Our data shed light on the early changes in pregnant obese women and suggest that RAS dysregulation is a prerequisite rather than a consequence of hypertensive disorders of pregnancy and other maternal neonatal complications.

Clinical Value of the Combination Detection of Captopril Renal Scintigraphy and Plasma Renin Activity in the Diagnosis of Renal Hypertension.

OBJECTIVE: This study aimed to investigate the clinical value of the combination detection of captopril renal scintigraphy (CRS) and plasma renin activity (PRA) in the diagnosis of renal hypertension (RHR). METHODS: Retrospective analysis was conducted on the clinical data of 163 patients with suspected RHR admitted to our hospital from March 2019 to March 2021, and all patients underwent blood pressure, CRS and digital subtraction angiography (DSA). The patients were divided into the positive group (n = 100) and the negative group (n = 63) in accordance with the results of DSA examination. PRA, angiotensin II and aldosterone levels of the two groups were detected and compared. The receiver operating characteristic curve was used to analyse the CRS, PRA and combined diagnostic performance. RESULTS: The uptake ratio value after captopril intervention in the positive group was 36.71% ± 8.79%, which was significantly lower than that in the negative group (56.79% ± 10.09%, p < 0.05). The serum PRA level of the positive group was 4.70 ± 1.67 ng/mLꞏh, which was distinctly higher than that of the negative group (2.12 ± 1.03 ng/mLꞏh, p < 0.05). The sensitivity and Youden index under the combination detection (area under the curve (AUC) = 0.956, p < 0.001) were all higher than those under single detection. CONCLUSION: The combined detection of PRA and CRS can provide considerable evidence for the early diagnosis and treatment of RHR, which has a certain clinical value.

Clinical Value of the Combination Detection of Captopril Renal Scintigraphy and Plasma Renin Activity in the Diagnosis of Renal Hypertension

Objective: This study aimed to investigate the clinical value of the combination detection of captopril renal scintigraphy (CRS) and plasma renin activity (PRA) in the diagnosis of renal hypertension (RHR). Methods: Retrospective analysis was conducted on the clinical data of 163 patients with suspected RHR admitted to our hospital from March 2019 to March 2021, and all patients underwent blood pressure, CRS and digital subtraction angiography (DSA). The patients were divided into the positive group (n = 100) and the negative group (n = 63) in accordance with the results of DSA examination. PRA, angiotensin II and aldosterone levels of the two groups were detected and compared. The receiver operating characteristic curve was used to analyse the CRS, PRA and combined diagnostic performance. Results: The uptake ratio value after captopril intervention in the positive group was 36.71% ± 8.79%, which was significantly lower than that in the negative group (56.79% ± 10.09%, p < 0.05). The serum PRA level of the positive group was 4.70 ± 1.67 ng/mLꞏh, which was distinctly higher than that of the negative group (2.12 ± 1.03 ng/mLꞏh, p < 0.05). The sensitivity and Youden index under the combination detection (area under the curve (AUC) = 0.956, p < 0.001) were all higher than those under single detection. Conclusion: The combined detection of PRA and CRS can provide considerable evidence for the early diagnosis and treatment of RHR, which has a certain clinical value (AU)

Reference intervals for LC-MS /MS measurements of plasma renin activity, aldosterone, angiotensin II, and 24-hour urinary aldosterone in Northern Chinese Han population.

BACKGROUND: Examination of aldosterone to Renin Ratio (ARR) and plasma aldosterone concentration (PAC) or 24-h urinary aldosterone excretion (24-h UALD) was the necessary tests in confirmatory tests for primary aldosteronism (PA). We developed a combined liquid chromatography-tandem mass spectrometry method (LC-MS/MS) for plasma renin activity (PRA), PAC, and angiotensin II (Ang II) and investigated their reference intervals (RIs) in northern Chinese Han population. The RIs of 24-h UALD excretion were also studied using LC-MS/MS. METHODS: A total of 309 healthy volunteers were recruited in 3 cities in China. PRA, PAC, Ang II, and 24-h UALD were measured using the laboratory-developed LC-MS/MS. Multiple linear regression and the variance component model were applied to determine if the RI needed to be split. The RIs of PRA, PAC, and Ang II were determined using the nonparametric percentile method. RESULTS: The laboratory-developed LC-MS/MS method was verified and showed good performance. Standard deviation ratio (SDR) sex for PAC and SDR region for Ang II are 0.466 and 0.407, respectively, indicating that the RIs of PAC and Ang II must be divided by sex and region, respectively. In addition, the SDR 24hUK for 24-h UALD is 0.579, indicating that the RI of 24-h UALD must be partitioned by urine potassium. CONCLUSION: RIs were established for tests related to the renin-angiotensin-aldosterone system in the apparently healthy northern Chinese Han population by the LC-MS/MS method.