Local aldosterone release and CYP11B2 expression in response to angiotensin peptides, glucose, and potassium - an ex vivo study on murine colon.

We have previously described local aldosterone synthesis in mouse colon. In the renin-angiotensin-aldosterone system (RAAS), angiotensin II (Ang II) peptide is the physiological factor which stimulates aldosterone synthesis in the adrenal glands. We have recently demonstrated that Ang II stimulates aldosterone synthesis also in mouse colon. Here, we conducted a 75-min ex vivo incubation of murine colonic tissue and evaluated the effects of three other Ang peptides, Ang I (1 µM), Ang III (0.1 µM) and Ang (1-7) (0.1 µM) on aldosterone synthesis. As a possible mechanism, their effects on tissue levels of the rate-limiting enzyme, aldosterone synthase (CYP11B2) were measured by ELISA and Western blot. Ang III significantly elevated the amount of tissue CYP11B2 protein in colon. The values of released aldosterone in colon tissue incubation were increased over the control in the presence of Ang I, II or III, however, being statistically non-significant. In Western blot analysis, the values of tissue CYP11B2 protein content were elevated by Ang I and II. Ang (1-7) alone in colon did not influence CYP11B2 protein levels in the incubation experiment but showed higher aldosterone release without statistical significance. Ang (1-7) showed an antagonistic effect towards Ang II in release of aldosterone in adrenal gland. An overall estimation of a single peptide (three measured variables), the results were always in an increasing direction. The responses of aldosterone synthesis to high levels of glucose (44 mM) and potassium (18.8 mM) as physiological stimulators in vivo were investigated in the colon incubation. Glucose, equal to four times the concentration of the control buffer in the incubation, showed higher values of aldosterone release in colon than control without statistical significance similarly to the effect seen in adrenal glands. Increasing the concentration of potassium in the incubation buffer exerted no effect on colonic aldosterone production. Intriguingly, no correlation was found between aldosterone release and the tissue CYP11B2 protein content in colon. In summary, the response of colonic aldosterone synthesis to different Ang peptides resembles, but is not identical to, the situation in the adrenal glands.

Kinetics of Intermediate Release Enhances P450 11B2-Catalyzed Aldosterone Synthesis.

The mitochondrial enzyme cytochrome P450 11B2 (aldosterone synthase) catalyzes the 3 terminal transformations in the biosynthesis of aldosterone from 11-deoxycorticosterone (DOC): 11ß-hydroxylation to corticosterone, 18-hydroxylation, and 18-oxidation. Prior studies have shown that P450 11B2 produces more aldosterone from DOC than from the intermediate corticosterone and that the reaction sequence is processive, with intermediates remaining bound to the active site between oxygenation reactions. In contrast, P450 11B1 (11ß-hydroxylase), which catalyzes the terminal step in cortisol biosynthesis, shares a 93% amino acid sequence identity with P450 11B2, converts DOC to corticosterone, but cannot synthesize aldosterone from DOC. The biochemical and biophysical properties of P450 11B2, which enable its unique 18-oxygenation activity and processivity, yet are not also represented in P450 11B1, remain unknown. To understand the mechanism of aldosterone biosynthesis, we introduced point mutations at residue 320, which partially exchange the activities of P450 11B1 and P450 11B2 (V320A and A320V, respectively). We then investigated NADPH coupling efficiencies, binding kinetics and affinities, and product formation of purified P450 11B1 and P450 11B2, wild-type, and residue 320 mutations in phospholipid vesicles and nanodiscs. Coupling efficiencies for the 18-hydroxylase reaction with corticosterone as the substrate failed to correlate with aldosterone synthesis, ruling out uncoupling as a relevant mechanism. Conversely, corticosterone dissociation rates correlated inversely with aldosterone production. We conclude that intermediate dissociation kinetics, not coupling efficiency, enable P450 11B2 to synthesize aldosterone via a processive mechanism. Our kinetic data also suggest that the binding of DOC to P450 11B enzymes occurs in at least two distinct steps, favoring an induced-fit mechanism.

Zona Glomerulosa-Derived Klotho Modulates Aldosterone Synthase Expression in Young Female Mice.

Klotho plays a critical role in the regulation of ion and fluid homeostasis. A previous study reported that haplo-insufficiency of Klotho in mice results in increased aldosterone synthase (CYP11B2) expression, elevated plasma aldosterone, and high blood pressure. This phenotype was presumed to be the result of diminished Klotho expression in zona glomerulosa (zG) cells of the adrenal cortex; however, systemic effects on adrenal aldosterone production could not be ruled out. To examine whether Klotho expressed in the zG is indeed a critical regulator of aldosterone synthesis, we generated a tamoxifen-inducible, zG-specific mouse model of Klotho deficiency by crossing Klotho-flox mice with Cyp11b2-CreERT mice (zG-Kl-KO). Tamoxifen-treated Cyp11b2-CreERT animals (zG-Cre) served as controls. Rosa26-mTmG reporter mice were used for Cre-dependent lineage-marking. Two weeks after tamoxifen induction, the specificity of the zG-Cre line was verified using immunofluorescence analysis to show that GFP expression was restricted to the zG. RNA in situ hybridization revealed a 65% downregulation of Klotho messenger RNA expression in the zG of zG-Kl-KO female mice at age 12 weeks compared to control mice. Despite this significant decrease, zG-Kl-KO mice exhibited no difference in plasma aldosterone levels. However, adrenal CYP11B2 expression and the CYP11B2 promotor regulatory transcription factors, NGFIB and Nurr1, were enhanced. Together with in vitro experiments, these results suggest that zG-derived Klotho modulates Cyp11b2 but does not evoke a systemic phenotype in young adult mice on a normal diet. Further studies are required to investigate the role of adrenal Klotho on aldosterone synthesis in aged animals.

Double somatic mutations in CTNNB1 and GNA11 in an aldosterone-producing adenoma.

Double somatic mutations in CTNNB1 and GNA11/Q have recently been identified in a small subset of aldosterone-producing adenomas (APAs). As a possible pathogenesis of APA due to these mutations, an association with pregnancy, menopause, or puberty has been proposed. However, because of its rarity, characteristics of APA with these mutations have not been well characterized. A 46-year-old Japanese woman presented with hypertension and hypokalemia. She had two pregnancies in the past but had no history of pregnancy-induced hypertension. She had regular menstrual cycle at presentation and was diagnosed as having primary aldosteronism after endocrinologic examinations. Computed tomography revealed a 2 cm right adrenal mass. Adrenal venous sampling demonstrated excess aldosterone production from the right adrenal gland. She underwent right laparoscopic adrenalectomy. The resected right adrenal tumor was histologically diagnosed as adrenocortical adenoma and subsequent immunohistochemistry (IHC) revealed diffuse immunoreactivity of aldosterone synthase (CYP11B2) and visinin like 1, a marker of the zona glomerulosa (ZG), whereas 11ß-hydroxylase, a steroidogenic enzyme for cortisol biosynthesis, was mostly negative. CYP11B2 IHC-guided targeted next-generation sequencing identified somatic CTNNB1 (p.D32Y) and GNA11 (p.Q209H) mutations. Immunofluorescence staining of the tumor also revealed the presence of activated ß-catenin, consistent with features of the normal ZG. The expression patterns of steroidogenic enzymes and related proteins indicated ZG features of the tumor cells. PA was clinically and biochemically cured after surgery. In conclusion, our study indicated that CTNNB1 and GNA11-mutated APA has characteristics of the ZG. The disease could occur in adults with no clear association with pregnancy or menopause.

Aldosterone synthase inhibitor (BI 690517) therapy for people with diabetes and albuminuric chronic kidney disease: A multicentre, randomized, double-blind, placebo-controlled, Phase I trial.

AIM: This Phase I study evaluated the safety and early efficacy of an aldosterone synthase inhibitor (BI 690517) in people with diabetes and albuminuric chronic kidney disease. METHODS: Double-blind, placebo-controlled study (NCT03165240) at 40 sites across Europe. Eligible participants [estimated glomerular filtration rate ≥20 and <75 ml/min/1.73 m2; urine albumin/creatinine ratio (UACR) ≥200 and <3500 mg/g] were randomized 6:1 to receive once-daily oral BI 690517 3, 10 or 40 mg, or eplerenone 25-50 mg, or placebo, for 28 days. The primary endpoint was the proportion of participants with drug-related adverse events (AEs). Secondary endpoints included changes from baseline in the UACR. RESULTS: Fifty-eight participants were randomized and treated from 27 November 2017 to 16 April 2020 (BI 690517: 3 mg, n = 18; 10 mg, n = 13; 40 mg, n = 14; eplerenone, n = 4; placebo, n = 9) for 28 days. Eight (13.8%) participants experienced drug-related AEs [BI 690517: 3 mg (two of 18); 10 mg (four of 13); 40 mg (two of 14)], most frequently constipation [10 mg (one of 13); 40 mg (one of 14)] and hyperkalaemia [3 mg (one of 18); 10 mg (one of 13)]. Most AEs were mild to moderate; one participant experienced severe hyperkalaemia (serum potassium 6.9 mmol/L; BI 690517 10 mg). UACR responses [≥20% decrease from baseline (first morning void urine) after 28 days] were observed for 80.0% receiving BI 690517 40 mg (eight of 10) versus 37.5% receiving placebo (three of eight). Aldosterone levels were suppressed by BI 690517, but not eplerenone or placebo. CONCLUSIONS: BI 690517 was generally well tolerated, reduced plasma aldosterone and may decrease albuminuria in participants with diabetes and albuminuric chronic kidney disease.

A comparison of the performance of 68Ga-Pentixafor PET/CT versus adrenal vein sampling for subtype diagnosis in primary aldosteronism.

Objective: To investigate the diagnostic efficiency and prognostic value of 68Ga-Pentixafor PET/CT in comparison with adrenal vein sampling (AVS) for functional lateralization in primary aldosteronism (PA). Histology and long-term clinical follow-up normally serve as the gold standard for such diagnosis. Methods: We prospectively recruited 26 patients diagnosed with PA. All patients underwent 68Ga-Pentixafor PET/CT and AVS. Postsurgical biochemical and clinical outcomes of patients with unilateral primary aldosteronism (UPA), as diagnosed by PET/CT or AVS, were assessed by applying standardized Primary Aldosteronism Surgical Outcome (PASO) criteria. Immunohistochemistry (IHC) was performed to detect the expression of aldosterone synthase (CYP11B2) and CXCR4. Results: On total, 19 patients were diagnosed with UPA; of these, 13 patients were lateralized by both PET/CT and AVS, four patients were lateralized by PET-only, and two by AVS-only. Seven subjects with no lateralization on AVS and PET received medical therapy. All patients achieved complete biochemical success except one with nodular hyperplasia lateralized by AVS alone. The consistency between PET/CT and AVS outcomes was 77% (20/26). Moreover, CYP11B2-positive nodules were all CXCR4-positive and showed positive findings on PET. Patients who achieved complete biochemical and clinical success had a higher uptake on PET as well as stronger expression levels of CXCR4 and CYP11B2. Conclusion: Our analysis showed that 68Ga-Pentixafor PET/CT could enable non-invasive diagnosis in most patients with PA and identify additional cases of unilateral and surgically curable PA which could not be classified by AVS. 68Ga-Pentixafor PET/CT should be considered as a first-line test for the future classification of PA.

Chimeric Genes Causing 11ß-Hydroxylase Deficiency: Implications in Clinical and Molecular Diagnosis.

Deficiency of 11ß-hydroxylase (11ß-OHD) is the second most common cause of congenital adrenal hyperplasia (CAH), accounting for 0.2-8% of all cases. The disease is transmitted as an autosomal recessive trait and the underlying genetic causes of 11ß-OHD are primarily small pathogenic variants affecting the CYP11B1 gene coding the 11ß-hydroxylase enzyme. However, special events complicate the molecular diagnosis of 11ß-OHD such as an unequal crossing over between the CYP11B2 (coding aldosterone synthase enzyme) and CYP11B1 genes. The resulting allele contains a hybrid gene, with a CYP11B2 5'-end and a CYP11B1 3'-end, where the CYP11B1 gene is under the control of the CYP11B2 promoter and thus not responding to the adrenocorticotropin (ACTH) but to angiotensin II and K+. This leads a reduction of cortisol production in 11ß-OHD. In particular, CYP11B2/CYP11B1 chimeric genes can be distinguished into two groups depending on the breakpoint site: chimeras with breakpoint after the exon 5 of CYP11B2 preserve the aldosterone synthase activity, the others with breakpoint before exon 5 lose this function. In the last case, a more severe phenotype is expected. The aim of this review was to explore the setting of CYP11B2/CYP11B1 chimeras in 11ß-OHD, performing a careful review of clinical literature cases.

Results from a Phase 1 Study Assessing the Pharmacokinetics of the Aldosterone Synthase Inhibitor Baxdrostat in Participants with Varying Degrees of Renal Function.

Baxdrostat is a selective small-molecule aldosterone synthase inhibitor in development for treatment of hypertension and chronic kidney disease. This phase 1, open-label, parallel-group study assessed the safety and pharmacokinetics (PK) of baxdrostat in participants with varying degrees of renal function. Participants were enrolled into control (estimated glomerular filtration rate [eGFR] ≥60 mL/min), moderate to severe renal impairment (eGFR 15-59 mL/min), or kidney failure (eGFR <15 mL/min) groups and received a single 10-mg baxdrostat dose followed by 7 days of inpatient PK blood and urine sampling. Safety was assessed by adverse events, clinical laboratory evaluations, vital signs, physical examinations, and electrocardiograms (ECGs). Thirty-2 participants completed the study. There were no deaths and only 1 mild drug-related adverse event (diarrhea). No clinically meaningful changes in laboratory values, vital signs, physical examinations, or ECGs occurred. Plasma concentration-time curves of baxdrostat were similar among all groups. Urine PK parameters were similar (approximately 12% excreted) in the moderate to severe renal impairment and control groups. Inadequate urine production in the kidney failure group resulted in minimal urinary baxdrostat excretion. Renal impairment had no significant impact on systemic exposure or clearance of baxdrostat, suggesting that dose adjustment due to PK differences in patients with kidney disease is unnecessary.

Chronic activation of adrenal Gq signaling induces Cyp11b2 expression in the zona fasciculata and hyperaldosteronism.

Hyperaldosteronism is often associated with inappropriate aldosterone production and aldosterone synthase (Cyp11b2) expression. Normally, Cyp11b2 expression is limited to the adrenal zona glomerulosa (ZG) and regulated by angiotensin II which signals through Gq protein-coupled receptors. As cells migrate inwards, they differentiate into 11ß-hydroxylase-expressing zona fasciculata (ZF) cells lacking Cyp11b2. The mechanism causing ZG-specific aldosterone biosynthesis is still unclear. We investigated the effect of chronic Gq signaling using transgenic mice with a clozapine N-oxide (CNO)-activated human M3 muscarinic receptor (DREADD) coupled to Gq (hM3Dq) that was expressed throughout the adrenal cortex. CNO raised circulating aldosterone in the presence of a high sodium diet with greater response seen in females compared to males. Immunohistochemistry and transcriptomics indicated disrupted zonal Cyp11b2 expression while Wnt signaling remained unchanged. Chronic Gq-DREADD signaling also induced an intra-adrenal RAAS in CNO-treated mice. Chronic Gq signaling disrupted adrenal cortex zonal aldosterone production associated with ZF expression of Cyp11b2.

Multifocal, Asymmetric Bilateral Primary Aldosteronism Cannot be Excluded by Strong Adrenal Vein Sampling Lateralization: An International Retrospective Cohort Study.

BACKGROUND: Primary aldosteronism (PA) has been broadly dichotomized into unilateral and bilateral forms. Adrenal vein sampling (AVS) lateralization indices (LI) ≥2 to 4 are the standard-of-care to recommend unilateral adrenalectomy for presumed unilateral PA. We aimed to assess the rates and characteristics of residual PA after AVS-guided adrenalectomy. METHODS: We conducted an international, retrospective, cohort study of patients with PA from 7 referral centers who underwent unilateral adrenalectomy based on LI≥4 on baseline and/or cosyntropin-stimulated AVS. Aldosterone synthase (CYP11B2) immunohistochemistry and next generation sequencing were performed on available formalin-fixed paraffin-embedded adrenal tissue. RESULTS: The cohort included 283 patients who underwent AVS-guided adrenalectomy, followed for a median of 326 days postoperatively. Lack of PA cure was observed in 16% of consecutive patients, and in 22 patients with lateralized PA on both baseline and cosyntropin-stimulated AVS. Among patients with residual PA postoperatively, 73% had multiple CYP11B2 positive areas within the resected adrenal tissue (versus 23% in those cured), wherein CACNA1D mutations were most prevalent (63% versus 33% in those cured). In adjusted regression models, independent predictors of postoperative residual PA included Black versus White race (odds ratio, 5.10 [95% CI, 1.45-17.86]), AVS lateralization only at baseline (odds ratio, 8.93 [95% CI 3.00-26.32] versus both at baseline and after cosyntropin stimulation), and CT-AVS disagreement (odds ratio, 2.75 [95% CI, 1.20-6.31]). CONCLUSIONS: Multifocal, asymmetrical bilateral PA is relatively common, and it cannot be excluded by robust AVS lateralization. Long-term postoperative monitoring should be routinely pursued, to identify residual PA and afford timely initiation of targeted medical therapy.

Neonatal salt wasting syndrome: Aldosterone synthase deficiency caused by a new splicing variant in CYP11B2.

Aldosterone synthase deficiency (ASD) is a rare autosomal recessive disorder involving isolated aldosterone deficiency without any compromise of other adrenal hormones. This condition manifests mainly in the neonatal period and in infants as a salt wasting syndrome with vomiting and failure to thrive. Due to its potentially life-threatening effects, ASD requires a careful and early diagnosis based on appropriate hormonal investigations in order to initiate adequate management: rehydration as well as salt and fludrocortisone supplementation. Genetic analysis of the CYP11B2 gene will confirm ASD in most cases. We report the case of a newborn with a typical clinical presentation associated with some uncommon phenotypic features (hyperhidrosis, liver injury). Furthermore, our patient carries a new CYP11B2 splicing variant to be added to the approximately 60 pathogenic or likely pathogenic variants already reported.

No extra-adrenal aldosterone production in various human cell lines.

Extra-adrenal de novo aldosterone (Aldo) production has been described inconsistently. Systematic data based upon state-of-the-art technology including validated controls are sparse. We hypothesized that aldosterone synthase (CYP11B2) expression and de novo Aldo production are absent in nonadrenal human cell lines, either immortalized cell lines or commercially available primary cell lines, including peripheral blood mononuclear cells (PBMCs) of individuals without and with primary hyperaldosteronism (PA). CYP11B2-transfected COS-7 and endogenous CYP11B2 expressing adrenal H295R cells served as positive controls. Various well-characterized, purchased, immortalized (BeWo, HEK293, HTR-8/SVneo, JEG-3) and primary (HAEC, HLEC, HRGEC, HRMC, HUAEC, HUVEC, PBMC) cell lines as well as self-isolated PBMCs from PA patients (n = 5) were incubated with the steroid hormone substrates progesterone, deoxycorticosterone, corticosterone or 18-OH-corticosterone with and without Ang II for 24 h to assess CYP11B2 enzymatic activity. CYP11B2 expression was analyzed by real-time PCR and liquid chromatography-mass spectrometry was used to quantify Aldo production. Pronounced CYP11B2 mRNA expression and Aldo production were observed in both positive controls, which followed an incremental time course. Neither substrates alone nor coincubation with Ang II significantly stimulated CYP11B2 expression or Aldo production in various immortalized and primary cell lines and PBMCs of PA patients. These results strongly support the absence of relevant de novo extra-adrenal Aldo production in nonadrenal cells, including blood mononuclear cells, irrespective of the absence or presence of autonomous adrenal Aldo production.

Extra-adrenal aldosterone: a mini review focusing on the physiology and pathophysiology of intrarenal aldosterone.

PURPOSE: Accumulating evidence has demonstrated the existence of extra-adrenal aldosterone in various tissues, including the brain, heart, vascular, adipocyte, and kidney, mainly based on the detection of the CYP11B2 (aldosterone synthase, cytochrome P450, family 11, subfamily B, polypeptide 2) expression using semi-quantitative methods including reverse transcription-polymerase chain reaction and antibody-based western blotting, as well as local tissue aldosterone levels by antibody-based immunosorbent assays. This mini-review highlights the current evidence and challenges in extra-adrenal aldosterone, focusing on intrarenal aldosterone. METHODS: A narrative review. RESULTS: Locally synthesized aldosterone may play a vital role in various physio-pathological processes, especially cardiovascular events. The site of local aldosterone synthesis in the kidney may include the mesangial cells, podocytes, proximal tubules, and collecting ducts. The synthesis of renal aldosterone may be regulated by (pro)renin receptor/(pro)renin, angiotensin II/Angiotensin II type 1 receptor, wnt/ß-catenin, cyclooxygenase-2/prostaglandin E2, and klotho. Enhanced renal aldosterone release promotes Na+ reabsorption and K+ excretion in the distal nephron and may contribute to the progress of diabetic nephropathy and salt-related hypertension. CONCLUSIONS: Inhibition of intrarenal aldosterone signaling by aldosterone synthase inhibitors or mineralocorticoid receptor antagonists may be a hopeful pharmacological technique for the therapy of diabetic nephropathy and saltrelated hypertension. Yet, current reports are often conflicting or ambiguous, leading many to question whether extra-adrenal aldosterone exists, or whether it is of any physiological and pathophysiological significance.

Methods Article for a Study Protocol: Study Design and Baseline Characteristics for Aldosterone Synthase Inhibition in Chronic Kidney Disease.

INTRODUCTION: Aldosterone synthase (AS) inhibition may overcome increased aldosterone production in response to renin-angiotensin system inhibition. BI 690517 is an AS inhibitor under investigation for chronic kidney disease (CKD). METHODS: This multinational, phase II, double-blind study (NCT05182840) investigated the efficacy and safety of daily oral BI 690517, with or without empagliflozin 10 mg, in participants with CKD. The primary endpoint was change from baseline in urine albumin:creatinine ratio (UACR) at week 14. Between February 18, 2022, and December 30, 2022, 714 adults already treated by angiotensin-converting enzyme inhibitor (30.5%) or angiotensin receptor blocker (69.8%) were randomized (1:1) to an 8-week run-in to assign background empagliflozin (n = 356) or placebo (n = 358). Participants in each group were then randomized (1:1:1:1) to a 14-week treatment period with BI 690517 (3 mg, 10 mg, or 20 mg) or placebo. Of the 714 participants who entered run-in, 586 were randomized to the treatment period. They were predominantly men (66.6%) of white race (58.4%) with a mean (standard deviation [SD]) age of 63.8 (11.3) years. Type 2 diabetes was present in 414 participants (70.6%). The baseline mean (SD) estimated glomerular filtration rate was 51.9 (17.7) mL/min/1.73 m2, and median (interquartile range) UACR was 426.3 mg/g (205.3-888.5). CONCLUSION: This study will inform dose selection for further clinical development and determine whether BI 690517, with or without background empagliflozin, has a favorable safety profile and potential for additive kidney protection in participants with CKD already treated with a renin-angiotensin system inhibitor.

Efficacy and safety of aldosterone synthase inhibition with and without empagliflozin for chronic kidney disease: a randomised, controlled, phase 2 trial.

BACKGROUND: Excess aldosterone accelerates chronic kidney disease progression. This phase 2 clinical trial assessed BI 690517, an aldosterone synthase inhibitor, for efficacy, safety, and dose selection. METHODS: This was a multinational, randomised, controlled, phase 2 trial. People aged 18 years or older with an estimated glomerular filtration rate (eGFR) of 30 to less than 90 mL/min/1·73 m2, a urine albumin to creatinine ratio (UACR) of 200 to less than 5000 mg/g, and serum potassium of 4·8 mmol/L or less, taking an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker, were enrolled. Participants were randomly assigned (1:1) to 8 weeks of empagliflozin or placebo run-in, followed by a second randomisation (1:1:1:1) to 14 weeks of treatment with once per day BI 690517 at doses of 3 mg, 10 mg, or 20 mg, or placebo. Study participants, research coordinators, investigators, and the data coordinating centre were masked to treatment assignment. The primary endpoint was the change in UACR measured in first morning void urine from baseline (second randomisation) to the end of treatment. This study is registered with ClinicalTrials.gov (NCT05182840) and is completed. FINDINGS: Between Feb 18 and Dec 30, 2022, of the 714 run-in participants, 586 were randomly assigned to receive BI 690517 or placebo. At baseline, 33% (n=196) were women, 67% (n=390) were men, 42% (n=244) had a racial identity other than White, and mean participant age was 63·8 years (SD 11·3). Mean baseline eGFR was 51·9 mL/min/1·73 m2 (17·7) and median UACR was 426 mg/g (IQR 205 to 889). Percentage change in first morning void UACR from baseline to the end of treatment at week 14 was -3% (95% CI -19 to 17) with placebo, -22% (-36 to -7) with BI 690517 3 mg, -39% (-50 to -26) with BI 690517 10 mg, and -37% (-49 to -22) with BI 690517 20 mg monotherapy. BI 690517 produced similar UACR reductions when added to empagliflozin. Investigator-reported hyperkalaemia occurred in 10% (14/146) of those in the BI 690517 3 mg group, 15% (22/144) in the BI 690517 10 mg group, and 18% (26/146) in the BI 690517 20 mg group, and in 6% (nine of 147) of those receiving placebo, with or without empagliflozin. Most participants with hyperkalaemia did not require intervention (86% [72/84]). Adrenal insufficiency was an adverse event of special interest reported in seven of 436 study participants (2%) receiving BI 690517 and one of 147 participants (1%) receiving matched placebo. No treatment-related deaths occurred during the study. INTERPRETATION: BI 690517 dose-dependently reduced albuminuria with concurrent renin-angiotensin system inhibition and empagliflozin, suggesting an additive efficacy for chronic kidney disease treatment without unexpected safety signals. FUNDING: Boehringer Ingelheim.

Hypertension and Lorundrostat: Key Discoveries From the TARGET-HTN Trial.

Hypertension, characterized by persistent high blood pressure levels, is a major global health concern, contributing significantly to the risk of cardiovascular diseases (CVD) and overall mortality. It is classified into primary and secondary hypertension, with its prevalence steadily increasing due to ageing populations and unhealthy lifestyle factors. The World Health Organization (WHO) reports a staggering rise in hypertension cases, affecting one in 3 adults worldwide, doubling from 1990 to 2019. A significant development in the field of hypertension treatment is the Target-HTN trial, which investigated the efficacy of lorundrostat, an aldosterone synthase inhibitor, in reducing systolic blood pressure. This trial involved 2 cohorts. Cohort 1, comprising patients with suppressed plasma renin activity and elevated serum aldosterone levels, showed promising results. Lorundrostat doses of 100 mg and 50 mg administered once daily led to substantial reductions in systolic blood pressure compared to a placebo group. Cohort 2, although considered exploratory, also exhibited a notable reduction in systolic blood pressure with a 100 mg once-daily dose of lorundrostat. In conclusion, the Target-HTN trial has demonstrated that lorundrostat, an aldosterone synthase inhibitor, holds promise as an innovative therapeutic approach for reducing systolic blood pressure, especially in hypertensive patients with suppressed plasma renin activity and elevated serum aldosterone levels. These findings advocate for the initiation of Phase 3 trials to further validate the safety and efficacy of lorundrostat in a larger and more diverse patient population.

Assessment of methomyl-induced adrenal gland disruption in rat fetuses and pups: Potential protective effects of propolis supplementation.

The present study aimed to unravel the possible adverse effects of methomyl on the developing adrenal gland of rat fetuses and pups. Additionally, this study explored the potential improving effects of propolis against these possible hazards induced by methomyl exposure. To achieve that, pregnant rats were divided into four groups: control group, received 1 mL distilled water, propolis group, received 1 mL propolis at a dose of 300 mg/kg, methomyl group, received 1 mL methomyl at a dose of 2 mg/kg, and combined group, received 1 mL methomyl followed by 1 mL propolis, an hour later at the same previous doses. The results revealed that methomyl exposure, during pregnancy and lactation, induced many histological and ultrastructural changes, caused DNA damage and downregulated the expression of steroidogenic acute regulatory (StAR) and CYP11B2 genes in the adrenal glands of both rat fetuses and pups. Interestingly, propolis supplementation demonstrated a remarkable ability to mitigate these deleterious effects and restored the histology and ultrastructure architecture of the adrenal glands of both fetuses and pups, as well as decreased DNA damage and upregulated the expression of StAR and CYP11B2 genes in the adrenal gland of rat fetuses and pups. In conclusion, our study highlights the potential hazardous impact of methomyl exposure during pregnancy and lactation on the development of the adrenal gland in rat fetuses and pups, moreover, the study presents a new approach to alleviate these effects through propolis administration which could be used as a dietary supplement to mitigate the adverse effects of methomyl exposure.

Aldosterone and aldosterone synthase inhibitors in cardiorenal disease.

Modulation of the renin-angiotensin-aldosterone system is a foundation of therapy for cardiovascular and kidney diseases. Excess aldosterone plays an important role in cardiovascular disease, contributing to inflammation, fibrosis, and dysfunction in the heart, kidneys, and vasculature through both genomic and mineralocorticoid receptor (MR)-mediated as well as nongenomic mechanisms. MR antagonists have been a key therapy for attenuating the pathologic effects of aldosterone but are associated with some side effects and may not always adequately attenuate the nongenomic effects of aldosterone. Aldosterone is primarily synthesized by the CYP11B2 aldosterone synthase enzyme, which is very similar in structure to other enzymes involved in steroid biosynthesis including CYP11B1, a key enzyme involved in glucocorticoid production. Lack of specificity for CYP11B2, off-target effects on the hypothalamic-pituitary-adrenal axis, and counterproductive increased levels of bioactive steroid intermediates such as 11-deoxycorticosterone have posed challenges in the development of early aldosterone synthase inhibitors such as osilodrostat. In early-phase clinical trials, newer aldosterone synthase inhibitors demonstrated promise in lowering blood pressure in patients with treatment-resistant and uncontrolled hypertension. It is therefore plausible that these agents offer protection in other disease states including heart failure or chronic kidney disease. Further clinical evaluation will be needed to clarify the role of aldosterone synthase inhibitors, a promising class of agents that represent a potentially major therapeutic advance.

Case Report: A combination of chimeric CYP11B2/CYP11B1 and a novel p.Val68Gly CYP11B1 variant causing 11ß-Hydroxylase deficiency in a Chinese patient.

Introduction: 11ß-Hydroxylase deficiency (11ß-OHD, OMIM#202010) is the second most common form of congenital adrenal hyperplasia (CAH) caused by pathogenic variants in the CYP11B1 gene. Both single nucleotide variations (SNV)/small insertion and deletion and genomic rearrangements of CYP11B1 are important causes of 11ß-OHD. Among these variant types, pathogenic CYP11B2/CYP11B1 chimeras only contribute to a minority of cases. Heterozygote cases (chimera combined with SNV) are very rare, and genetic analysis of these cases can be challenging. Case presentation: We presented a suspected 11ß-OHD female patient with incomplete virilization, adrenal hyperplasia, and hypokalemia hypertension. Whole exome sequencing (WES) revealed that the patient carried both a chimeric CYP11B2/CYP11B1 and a novel missense variant, NM_000497.4: c.203T>G, p.Val68Gly (chr8:143961027) in CYP11B1, which were confirmed by CNVplex and Sanger sequencing, respectively. The patient's manifestations and genetic findings confirmed the diagnosis of 11ß-OHD, and oral dexamethasone was administered as a subsequent treatment. Conclusion: This report showed a rare CYP11B2/CYP11B1 chimera combined with a novel missense variant in a 11ß-OHD female patient. The result expands variant spectrum of CYP11B1 and suggests that both chimera and CYP11B1 variant screening should be performed simultaneously in suspected cases of 11ß-OHD. To our knowledge, this is the first report about CYP11B2/CYP11B1 chimera detected by WES analysis. WES combined with CNV analysis is an efficient method in the genetic diagnosis of this rare and complex disorder.