Aldosterone and the risk of hypertension

Proteomic analyses on chicken breast meat with white striping myopathy

White striping (WS) is an emerging myopathy that results in significant economic losses as high as $1 billion (combined with losses derived from other breast myopathies including woody breast and spaghetti meat) to the global poultry industry. White striping is detected as the occurrence of white lines on raw poultry meat. The exact etiologies for WS are still unclear. Proteomic analyses of co-expressed WS and woody breast phenotypes previously demonstrated dysfunctions in carbohydrate metabolism, protein synthesis, and calcium buffering capabilities in muscle cells. In this study, we conducted shotgun proteomics on chicken breast fillets exhibiting only WS that were collected at approximately 6 h postmortem. After determining WS severity, protein extractions were conducted from severe WS meat with no woody breast (WB) condition (n = 5) and normal non-affected (no WS) control meat (n = 5). Shotgun proteomics was conducted by Orbitrap Lumos, tandem mass tag (TMT) analysis. As results, 148 differentially abundant proteins (|fold change|>1.4; p-value < 0.05) were identified in the WS meats compared with controls. The significant canonical pathways included BAG2 signaling pathway, glycogen degradation II, isoleucine degradation I, aldosterone signaling in epithelial cells, and valine degradation I. The potential upstream regulators include LIPE, UCP1, ATP5IF1, and DMD. The results of this study provide additional insights into the cellular mechanisms on the WS myopathy and meat quality.

A Humanized and Viable Animal Model for Congenital Adrenal Hyperplasia-CYP21A2-R484Q Mutant Mouse

Congenital Adrenal Hyperplasia (CAH) is an autosomal recessive disorder impairing cortisol synthesis due to reduced enzymatic activity. This leads to persistent adrenocortical overstimulation and the accumulation of precursors before the blocked enzymatic step. The predominant form of CAH arises from mutations in CYP21A2, causing 21-hydroxylase deficiency (21-OHD). Despite emerging treatment options for CAH, it is not always possible to physiologically replace cortisol levels and counteract hyperandrogenism. Moreover, there is a notable absence of an effective in vivo model for pre-clinical testing. In this work, we developed an animal model for CAH with the clinically relevant point mutation p.R484Q in the previously humanized CYP21A2 mouse strain. Mutant mice showed hyperplastic adrenals and exhibited reduced levels of corticosterone and 11-deoxycorticosterone and an increase in progesterone. Female mutants presented with higher aldosterone concentrations, but blood pressure remained similar between wildtype and mutant mice in both sexes. Male mutant mice have normal fertility with a typical testicular appearance, whereas female mutants are infertile, exhibit an abnormal ovarian structure, and remain in a consistent diestrus phase. Conclusively, we show that the animal model has the potential to contribute to testing new treatment options and to prevent comorbidities that result from hormone-related derangements and treatment-related side effects in CAH patients.

Unraveling the complex pathophysiology of heart failure: insights into the role of renin-angiotensin-aldosterone system (RAAS) and sympathetic nervous system (SNS)

Heart failure (HF) is a widespread disease with significantly elevated mortality, morbidity, and hospitalization rates. Dysregulation of the sympathetic nervous system (SNS) and renin-angiotensin-aldosterone system (RAAS) are both postulated to be significant regulators of cardiovascular function, thereby playing a pivotal role in its pathophysiology. The RAAS is a sophisticated hormonal system that controls electrolyte homeostasis, fluid balance, and blood pressure. Angiotensin II, which operates to constrict blood vessels and raise blood pressure, is its principal effector molecule. The RAAS is frequently hyperactive in HF, which increases fluid retention and worsens cardiac function. The SNS is frequently hyperactive in heart failure, which increases the workload on the heart and worsens symptoms. This review will discuss what is currently known about the pathophysiology of heart failure, specifically in the context of RAAS and the SNS, in-depth to emphasize the knowledge gap that necessitates more research.

Effect of different anti-cardiovascular disease treatments on the severity of obstructive sleep apnea

Obstructive sleep apnea (OSA) and cardiovascular co-morbidities have a mutually reinforcing effect, but existing studies have focussed only on the improvement of the associated co-morbidities by treatment for OSA. To provide fresh guidelines for the treatment of OSA from a co-morbidity standpoint, we conducted a systematic search of Web of Science, PubMed, EMBASE, and the Cochrane Library for articles published from inception up to 2 May 2023. Fourteen original studies of patients with OSA with cardiovascular co-morbidities and who received related treatment were included in the analysis. We found that diuretic treatment can reduce the apnea-hypopnea index in patients with OSA and hypertension (-19.41/h, p = 1.0 × 10-5 ), aldosterone-angiotensin inhibitors also have a 9.19/h reduction (p = 0.003), while the effect of renal sympathetic denervation is insignificant (-2.32/h, p = 0.19). The short-term treatment (<4 weeks) did not show an improvement (-2.72/h, p = 0.16), while long-term treatment (>4 weeks) produced surprising outcomes (-12.78/h, p = 0.002). Patients with milder disease (baseline AHI < 35/h) had insignificant improvements (-1.05/h, p = 0.46), whereas those with more severe disease (baseline AHI > 35/h) could achieve satisfactory outcomes (-14.74/h, p < 0.00001). In addition, it also showed some improvement in the oxygen desaturation index and blood oxygen. Our results support the additional benefit of antihypertensive treatment for OSA symptoms, and the efficacy can be affected by different therapy, treatment duration, and severity levels. It could be useful in developing clinical therapy, educating patients, and exploring interaction mechanisms. The proposal was registered with PROSPERO (CRD42022351206).

The sustainable antihypertensive and target organ damage protective effect of transcranial focused ultrasound stimulation in spontaneously hypertensive rats

OBJECTIVE

In this study, we aimed to investigate the sustainable antihypertensive effects and protection against target organ damage caused by low-intensity focused ultrasound (LIFU) stimulation and the underlying mechanism in spontaneously hypertensive rats (SHRs) model.

METHODS AND RESULTS

SHRs were treated with ultrasound stimulation of the ventrolateral periaqueductal gray (VlPAG) for 20 min every day for 2 months. Systolic blood pressure (SBP) was compared among normotensive Wistar-Kyoto rats, SHR control group, SHR Sham group, and SHR LIFU stimulation group. Cardiac ultrasound imaging and hematoxylin-eosin and Masson staining of the heart and kidney were performed to assess target organ damage. The c-fos immunofluorescence analysis and plasma levels of angiotensin II, aldosterone, hydrocortisone, and endothelin-1 were measured to investigate the neurohumoral and organ systems involved. We found that SBP was reduced from 172 ± 4.2 mmHg to 141 ± 2.1 mmHg after 1 month of LIFU stimulation, P  < 0.01. The next month of treatment can maintain the rat's blood pressure at 146 ± 4.2 mmHg at the end of the experiment. LIFU stimulation reverses left ventricular hypertrophy and improves heart and kidney function. Furthermore, LIFU stimulation enhanced the neural activity from the VLPAG to the caudal ventrolateral medulla and reduced the plasma levels of ANGII and Aldo.

CONCLUSION

We concluded that LIFU stimulation has a sustainable antihypertensive effect and protects against target organ damage by activating antihypertensive neural pathways from VLPAG to the caudal ventrolateral medulla and further inhibiting the renin-angiotensin system (RAS) activity, thereby supporting a novel and noninvasive alternative therapy to treat hypertension.

Interaction of Vitamin D with Peptide Hormones with Emphasis on Parathyroid Hormone, FGF23, and the Renin-Angiotensin-Aldosterone System

The seminal discoveries that parathyroid hormone (PTH) and fibroblast growth factor 23 (FGF23) are major endocrine regulators of vitamin D metabolism led to a significant improvement in our understanding of the pivotal roles of peptide hormones and small proteohormones in the crosstalk between different organs, regulating vitamin D metabolism. The interaction of vitamin D, FGF23 and PTH in the kidney is essential for maintaining mineral homeostasis. The proteohormone FGF23 is mainly secreted from osteoblasts and osteoclasts in the bone. FGF23 acts on proximal renal tubules to decrease production of the active form of vitamin D (1,25(OH)₂D) by downregulating transcription of 1α-hydroxylase (CYP27B1), and by activating transcription of the key enzyme responsible for vitamin D degradation, 24-hydroxylase (CYP24A1). Conversely, the peptide hormone PTH stimulates 1,25(OH)₂D renal production by upregulating the expression of 1α-hydroxylase and downregulating that of 24-hydroxylase. The circulating concentration of 1,25(OH)₂D is a positive regulator of FGF23 secretion in the bone, and a negative regulator of PTH secretion from the parathyroid gland, forming feedback loops between kidney and bone, and between kidney and parathyroid gland, respectively. In recent years, it has become clear that vitamin D signaling has important functions beyond mineral metabolism. Observation of seasonal variations in blood pressure and the subsequent identification of vitamin D receptor (VDR) and 1α-hydroxylase in non-renal tissues such as cardiomyocytes, endothelial and smooth muscle cells, suggested that vitamin D may play a role in maintaining cardiovascular health. Indeed, observational studies in humans have found an association between vitamin D deficiency and hypertension, left ventricular hypertrophy and heart failure, and experimental studies provided strong evidence for a role of vitamin D signaling in the regulation of cardiovascular function. One of the proposed mechanisms of action of vitamin D is that it functions as a negative regulator of the renin-angiotensin-aldosterone system (RAAS). This finding established a novel link between vitamin D and RAAS that was unexplored until then. During recent years, major progress has been made towards a more complete understanding of the mechanisms by which FGF23, PTH, and RAAS regulate vitamin D metabolism, especially at the genomic level. However, there are still major gaps in our knowledge that need to be filled by future research. The purpose of this review is to highlight our current understanding of the molecular mechanisms underlying the interaction between vitamin D, FGF23, PTH, and RAAS, and to discuss the role of these mechanisms in physiology and pathophysiology.

In silico selectivity modeling of pyridine and pyrimidine based CYP11B1 and CYP11B2 inhibitors: A case study

DESIGN

of selective drug candidates for highly structural similar targets is a challenging task for researchers. The main objective of this study was to explore the selectivity modeling of pyridine and pyrimidine scaffold towards the highly homologous targets CYP11B1 and CYP11B2 enzymes by in silico (Molecular docking and QSAR) approaches. In this regard, a big dataset (n = 228) of CYP11B1 and CYP11B2 inhibitors were gathered and classified based on heterocyclic ring and the exhaustive analysis was carried out for pyridine and pyrimidinescaffolds. The LibDock algorithm was used to explore the binding pattern, screening, and identify the structural feature responsible for the selectivity of the ligands towards the studied targets. Finally, QSAR analysis was done to explore the correlation between various binding parameters and structural features responsible for the inhibitory activity and selectivity of the ligands in a quantitative way. The docking and QSAR analysis clearly revealed and distinguished the importance of structural features, functional groups attached for CYP11B2 and CYP11B1 selectivity for pyridine and pyrimidine analogs. Additionally, the docking analysis highlighted the differentiating amino acids residues for selectivity for ligands for each of the enzymes. The results obtained from this research work will be helpful in designing the selective CYP11B1/CYP11B2 inhibitors.

Dex modulates the balance of water-electrolyte metabolism by depressing the expression of AVP in PVN

Dexmedetomidine (Dex) is a highly selective α2 adrenergic agonist used in clinical anesthesia. Studies have shown that Dex can act on the collecting duct and reduce the body’s water reabsorption, thereby increasing water discharge. However, the specific mechanism of Dex on water homeostasis remains unclear. The hypothalamus is the regulatory center of water and salt balance and secretes related neurochemical hormones, such as arginine vasopressin (AVP), to regulate the discharge of water and salt. The paraventricular nucleus (PVN) and supraoptic nucleus (SON) in the hypothalamus are also considered to be the key targets of the thirst loop. They are responsible for the secretion of AVP. The suprachiasmatic nucleus (SCN) is also one of the brain regions where AVP neurons are densely distributed in the hypothalamus. This study used C57BL/6J mice for behavior, immunofluorescence, and blood analysis experiments. Our results showed that Dex could not only depress the expression of AVP in the PVN but also reduce serum AVP concentration. The animal water intake was decreased without impairing the difference in food consumption and the urine excretion was enhanced after the intraperitoneal injection of Dex, while AVP supplementation restored the water intake and inhibited the urine excretion of mice in the Dex group. In addition, the renin-angiotensin-aldosterone system is vital to maintaining serum sodium concentration and extracellular volume. We found that serum sodium, serum chloride, serum aldosterone (ALD) concentration, and plasma osmolality were decreased in the Dex group, which inhibited water reabsorption, and the plasma osmolarity of mice in the Dex group supplemented with AVP was significantly higher than that in Dex group. We also found that Dex significantly increased the concentration of blood urea nitrogen and decreased the concentration of creatinine within the normal range of clinical indicators, indicating that there was no substantive lesion in the renal parenchyma. These results showed that Dex could modulate the balance of water-electrolyte metabolism by depressing the expression of AVP in PVN without impairing renal function.

Combining virtual screening and in vitro evaluation for the discovery of potential CYP11B2 inhibitors

Aim: To search for highly bioactive hits for CYP11B2 inhibitors by virtual screening and in vitro evaluation. Materials & methods: Virtual screening of potential CYP11B2 inhibitors was performed by molecular docking and molecular dynamics simulation. Compound activity was determined by in vitro evaluation using MTT and ELISA assays. Results & conclusion: Based on the results of molecular docking and molecular dynamics simulation, nine lead hits were selected for in vitro biochemical testing. All hits in in vitro experiments had lower inhibitory effects on cell proliferation and certain inhibitory effects on aldosterone secretion. These hits may be excellent candidates for CYP11B2 inhibitors.

Divergent Characteristics of T-Cell Receptor Repertoire Between Essential Hypertension and Aldosterone-Producing Adenoma

Aldosterone-producing adenoma (APA) is a benign adrenal tumor that results in persistent hyperaldosteronism. As one major subtype of primary aldosteronism, APA leads to secondary hypertension that is associated with immune dysregulation. However, how the adaptive immune system, particularly the T-cell population, is altered in APA patients remains largely unknown. Here, we performed TCR sequencing to characterize the TCR repertoire between two age-matched groups of patients: one with APA and the other one with essential hypertension (EH). Strikingly, we found a significant reduction of TCR repertoire diversity in the APA group. Analyses on TCR clustering and antigen annotation further showed that the APA group possessed lower diversity in TCR clonotypes with non-common antigen-specific features, compared with the EH group. In addition, our results indicated that the strength of correlation between generation probabilities and frequencies of TCR clonotypes was significantly higher in the APA group than that in the EH group. Finally, we observed that clinical features, including plasma aldosterone level, aldosterone–renin ratio, and blood sodium level, were positively associated with the strength of correlation between generation and abundance of TCR clonotypes in the APA group. Our findings unveiled the correlation between T-cell immune repertoire and APA, suggesting a critical role of such adrenal adenoma in the T-cell immunity of patients with hypertension.

Primary Aldosteronism and Ischemic Heart Disease

Cardiovascular disease, in particular ischemic heart disease is a major cause of morbidity and mortality worldwide. Primary aldosteronism is the leading cause of secondary hypertension, yet commonly under diagnosed, and represents a major preventable risk factor. In contrast to historical teaching, recent studies have shown that excess aldosterone production is associated with increased burden of ischemic heart disease disproportionate to the effects caused by hypertension alone. Aldosterone through its genomic and non-genomic actions exerts various detrimental cardiovascular changes contributing to this elevated risk. Recognition of primary hyperaldosteronism and understanding the distinctive pathophysiology of ischemic heart disease in primary aldosteronism is crucial to develop strategies to improve outcomes.

Aldosterone and dexamethasone activate African lungfish mineralocorticoid receptor: Increased activation after removal of the amino-terminal domain

Aldosterone, the main physiological mineralocorticoid in humans and other terrestrial vertebrates, first appears in lungfish, which are lobe-finned fish that are forerunners of terrestrial vertebrates. Aldosterone activation of the MR regulates internal homeostasis of water, sodium and potassium, which was critical in the conquest of land by vertebrates. We studied transcriptional activation of the slender African lungfish MR by aldosterone, other corticosteroids and progesterone and find that aldosterone, 11-deoxycorticosterone, 11-deoxycortisol and progesterone have half-maximal responses (EC50 s) below 1 nM and are potential physiological mineralocorticoids. In contrast, EC50 s for corticosterone and cortisol were 23 nM and 66 nM, respectively. Unexpectedly, truncated lungfish MR, consisting of the DNA-binding, hinge and steroid-binding domains, had a stronger response to corticosteroids and progesterone than full-length lungfish MR, indicating that the N-terminal domain represses steroid activation of lungfish MR, unlike human MR in which the N-terminal domain contains an activation function. BLAST searches of GenBank did not retrieve a GR ortholog, leading us to test dexamethasone and triamcinolone for activation of lungfish MR. At 10 nM, both synthetic glucocorticoids are about 4-fold stronger than 10 nM aldosterone in activating full-length lungfish MR, leading us to propose that lungfish MR also functions as a GR.

Higher plasma aldosterone is associated with increased risk of cardiovascular events in hypertensive patients with suspected OSA: UROSAH data

OBJECTIVE

To evaluate the association of plasma aldosterone concentration (PAC) with incident cardiovascular disease (CVD) and all-cause mortality in hypertensive patients with suspected obstructive sleep apnea (OSA) and calculate the optimal cut-off value of PAC for this specific population.

PATIENTS AND METHODS

Participants with PAC at baseline in UROSAH in 2011-2013 were enrolled and followed up till 2021. Composite outcome included CVD and all-cause mortality. Cox proportional hazards model was used to evaluate the relationship between PAC and the composite outcome. Time-dependent ROC curve was used to determine the optimal cut-off value of PAC. Besides, we conducted subgroup analyses and sensitivity analyses.

RESULTS

3173 hypertensive participants aged 18-84 years comprised analytical sample. During a median follow-up of 7.3 years and 22640 person-years, 69 deaths and 343 cases of incident CVD occurred. The incidence of composite outcome was increased with elevation in tertile of PAC. Compared with the first tertile, the risk of CVD and all-cause death was higher in third tertile (HR=1.81, 95%CI: 1.39-2.35, P<0.001). Time-dependent ROC curve showed optimal threshold for PAC was 12.5ng/dl. Whether renin was suppressed or not (≤0.5 or >0.5ng/ml per h), elevated PAC was associated with an increased risk of CVD. Our results remained stable and consistent in sensitivity analyses.

CONCLUSION

Higher PAC was associated with increased risk of CVD and all-cause mortality in hypertensives with suspected OSA, even in the absence of primary aldosteronism (PA). Hypertensives with PAC≥12.5ng/dl showed a significantly increased risk of CVD, indicating that special attention and treatment were required in this specific population.

Association Between Serum Calcium and the Prevalence of Hypertension Among US Adults

Background: Hypertension is a significant risk factor of cardiovascular diseases, posing a serious threat to global health. Calcium plays an important role in regulating body homeostasis. The association of calcium with hypertension remains uncertain in the general population.

Methods and Results: Cross-sectional data from the 2007–2018 National Health and Nutrition Examination Survey (NHANES) were analyzed. Adjusted multivariable logistic regression analysis and restricted cubic spline were used to investigate the association of serum calcium with the prevalence of hypertension. A total of 26,778 participants were included. The increase in calcium levels showed a positive association with the prevalence of hypertension in all three models with ORs of 1.347 (1.249–1.454), 1.522 (1.401–1.654), and 1.438 (1.306–1.583). The further subgroup analysis demonstrated a robust trend across all categories by sex, age, race, BMI, and eGFR. The restricted cubic spline plot exhibited an S-curve relationship between calcium and hypertension.

Conclusion: Our cross-sectional study demonstrated a positive association between higher serum calcium level and the prevalence of hypertension. Our findings highlighted serum calcium level in hypertensive patients.

Associations of trauma and posttraumatic stress disorder with aldosterone in women

BACKGROUND

Posttraumatic stress disorder (PTSD) has been associated with increased cardiovascular risk, however, underlying mechanisms have not been fully specified. PTSD is associated with stress-related hormones, including dysregulated glucocorticoid activity. Dysregulation of aldosterone, a mineralocorticoid activated by psychological stress and implicated in cardiovascular damage, may be a relevant pathway linking PTSD and cardiovascular risk. Few studies to date have evaluated the association between PTSD and aldosterone, none with repeated measures of aldosterone. We examined if trauma and PTSD were associated with altered aldosterone levels relative to women unexposed to trauma.

METHODS

The association of trauma exposure and chronic PTSD with plasma aldosterone levels was investigated in 521 middle-aged women in the Nurses' Health Study II. Aldosterone was assessed at two time points, 10-16 years apart, and trauma exposure and PTSD were also ascertained for both time points. Regarding exposure assessment, women were characterized based on a structured diagnostic interview as: having chronic PTSD (PTSD at both time points; n = 174); being trauma-exposed (trauma exposure at first time point but no PTSD; n = 174); and being unexposed (no trauma exposure at either time point; reference group for all analyses; n = 173). Linear mixed models examined associations of trauma and PTSD status with log-transformed aldosterone levels, adjusting for covariates and health-related variables that may confound or lie on the pathway between PTSD and altered aldosterone levels.

RESULTS

Across the sample, mean aldosterone concentration decreased over time. Adjusting for covariates, women with chronic PTSD had significantly lower aldosterone levels averaged over time, compared to women unexposed to trauma (β = - 0.08, p = 0.04). Interactions between trauma/PTSD group and time were not significant, indicating change in aldosterone over time did not differ by trauma/PTSD status. Post-hoc exploratory analyses suggested that menopausal status partially mediated the relationship between chronic PTSD status and aldosterone level, such that postmenopausal status explained 7% of the effect of PTSD on aldosterone.

CONCLUSIONS

These findings indicate that PTSD is associated with lower levels of aldosterone. Further work is needed to understand implications of this type of dysregulation in a key biological stress system for cardiovascular and other health outcomes previously linked with PTSD.

Effects of eplerenone on cerebral aldosterone levels and brain lesions in spontaneously hypertensive rats

Evidence indicates that renin-angiotensin-aldosterone system (RAS) inhibitors can protect the brain in Alzheimer's disease and Parkinson's disease. The current study evaluated the relationship between aldosterone and tissue damage in the brains of spontaneously hypertensive rats (SHRs) and whether the RAS inhibitor eplerenone can mitigate the damage seen in these rats. SHRs were randomly divided into eplerenone (n = 10) and SHR (n = 10) groups, and Wistar-Kyoto (WKY) rats (n = 10) were used as controls. Eplerenone 50 mg/kg/day was administered orally to the eplerenone group. Pathological changes to the hippocampal formation, plasma and encephalic aldosterone, and plasma potassium levels were compared among the groups. After 10 weeks, rats in the eplerenone and SHR groups showed higher systolic BP (p = .01) than the control group. Aldosterone levels in the brain were higher in the SHR group (0.20 ± 0.06 pg/ml) than in the eplerenone (0.14 ± 0.05 pg/ml, p = .044) or control (0.12 ± 0.07 pg/ml, p = .007) groups. Plasma aldosterone levels in the SHR group were 1.7 times higher than those in the control group (p = .006). Cerebral cortex was thinner in the SHR group (225.18 ± 15.43 μm) than in the eplerenone (240.38 ± 12.85 μm, p < .01) or control (244.72 ± 18.92 μm, p < .01) groups. Thickness did not differ between the latter two groups. The SHR group exhibited apoptotic cells in the hippocampal formation, which were rare in the eplerenone and control groups. Plasma potassium levels were higher in the eplerenone group than those in the other two groups (p < .05). Our results showed that eplerenone can alleviate brain damage (thinning of cortex and increased apoptosis) caused by aldosterone in a rat model of hypertension.

Shared pathways for neuroprogression and somatoprogression in neuropsychiatric disorders

Activated immune-inflammatory, oxidative and nitrosative stress (IO&NS) pathways and consequent mitochondrial aberrations are involved in the pathophysiology of psychiatric disorders including major depression, bipolar disorder and schizophrenia. They offer independent and shared contributions to pathways underpinning medical comorbidities including insulin resistance, metabolic syndrome, obesity and cardiovascular disease - herein conceptualized as somatoprogression. This narrative review of human studies aims to summarize relationships between IO&NS pathways, neuroprogression and somatoprogression. Activated IO&NS pathways, implicated in the neuroprogression of psychiatric disorders, affect the pathogenesis of comorbidities including insulin resistance, dyslipidaemia, obesity and hypertension, and by inference, metabolic syndrome. These conditions activate IO&NS pathways, exacerbating neuroprogression in psychiatric disorders. The processes whereby proinflammatory cytokines, nitrosative and endoplasmic reticulum stress, NADPH oxidase isoforms, PPARγ inactivation, SIRT1 deficiency and intracellular signalling pathways impact lipid metabolism and storage are considered. Through associations between body mass index, chronic neuroinflammation and FTO expression, activation of IO&NS pathways arising from somatoprogression may contribute to neuroprogression. Early evidence highlights the potential of adjuvants targeting IO&NS pathways for treating somatoprogression and neuroprogression.

Role of spironolactone in the treatment of heart failure with preserved ejection fraction

Heart failure (HF) is the leading cause of morbidity and mortality globally. Heart failure with preserved ejection fraction (HFpEF) is currently responsible for about half of the patients affected with HF and is associated with impaired functional capacity, as well as significant morbidity due to frequent hospitalizations. Unfortunately, despite its poor prognosis, the management of HFpEF is very controversial and no therapy has been so far shown to reduce mortality in HFpEF. Spironolactone antagonizes the effect of aldosterone and can lead to a reduction in fibrosis and an improvement in left ventricular (LV) function. Furthermore, spironolactone decreases extracellular matrix turnover and myocardial collagen content and improves endothelial vasomotor dysfunction, mechanisms known to influence the progression of HF. Thus, given the aforementioned beneficial actions of spironolactone, extensive research has been conducted to explore the effects of spironolactone on HFpEF. Our review aims to present and discuss the clinical and scientific data pertaining to the role of spironolactone in the treatment of patients with HFpEF.

Consumption of Cuban Policosanol Improves Blood Pressure and Lipid Profile via Enhancement of HDL Functionality in Healthy Women Subjects: Randomized, Double-Blinded, and Placebo-Controlled Study

Policosanol has been reported to improve blood pressure, lipid profile, and HDL functionality via inhibition of cholesteryl ester transfer protein (CETP) both in vitro and in vivo in zebrafish and human models. However, there are limited reports and randomized, double-blinded trials on policosanol that could advocate the blood pressure-lowering effect in prehypertensive participants. Therefore, we performed in vitro, in vivo, and ex vivo experiments to provide more substantial and concrete data on the blood pressure-lowering effect of policosanol. Consumption of policosanol for 8 weeks enhanced plasma antioxidant activity. In the policosanol group, plasma total cholesterol (TC) and triglyceride (TG) levels were reduced up to 20% and 14%, respectively, and HDL-C level was elevated up to 1.3-fold compared to that at week 0. TG/HDL-C and cholesteryl ester transfer protein (CETP) activities were reduced up to 36% and 20%, respectively. Uptake of oxidized LDL in macrophages was reduced as oxidized species levels were reduced, and HDL₂-associated paraoxonase activities were enhanced by 60% compared to those at week 0. Encapsulation of policosanol into reconstituted HDL (PCO-rHDL) enhanced cholesterol efflux activity and insulin secretion capacity. In conclusion, consumption of policosanol for 8 weeks in healthy female subjects resulted in lowered blood pressure and CETP activity via elevation of HDL/apoA-I contents and enhancement of HDL functionalities, including cholesterol efflux and insulin secretion. These functional enhancements of HDL can contribute to the prevention of aging-related diseases, hypertension, and stroke.

Urotensin II promotes aldosterone expression in rat aortic adventitial fibroblasts

Urotensin II (UII) contributes to cardiovascular diseases by activating vasoactive peptides. The present study aimed to determine the effect of UII on aldosterone (ALD) and its receptor in cultured adventitial fibroblasts (AFs) and the tunica adventitia of rat vessels to explore the possible mechanisms underlying vascular remodeling. Expression levels of aldosterone and its receptor on tunica adventitia were determined using immunohistochemistry. Growth‑arrested AFs and tunica adventitia from rat vessels were incubated with UII and inhibitors of various signal transduction pathways. ALD receptor (ALD‑R) mRNA expression levels and ALD protein exoression levels were determined by reverse transcription‑quantitative polymerase chain reaction and ELISA, respectively. Aldosterone and its receptors were expressed on tunica adventitia. UII promoted ALD protein secretion from cells in a dose‑ and time‑dependent manner. ALD‑R mRNA expression in cells was also dysregulated. Furthermore, the effects of UII were substantially inhibited by treatment with the inhibitors PD98059, Y‑27632, H‑7, CSA and nicardipine. These results were further verified in the tunica adventitia of rat vessels. The present findings indicated that UII stimulated ALD protein secretion and ALD‑R mRNA expression in AFs and in the tunica adventitia of rat vessels; moreover, this effect may be mediated by signal transduction pathways involving MAPK, Rho, PKC, calcineurin and Ca2+. UII may also contribute to vascular remodeling by stimulating the production of ALD and its receptor.

Continuum of Renin-Independent Aldosteronism in Normotension

Primary aldosteronism is a severe form of autonomous aldosteronism. Milder forms of autonomous and renin-independent aldosteronism may be common, even in normotension. We characterized aldosterone secretion in 210 normotensives who had suppressed plasma renin activity (<1.0 ng/mL per hour), completed an oral sodium suppression test, received an infusion of angiotensin II, and had measurements of blood pressure and renal plasma flow. Continuous associations between urinary aldosterone excretion rate, renin, and potassium handling were investigated. Severe autonomous aldosterone secretion that was consistent with confirmed primary aldosteronism was defined based on accepted criteria of an aldosterone excretion rate >12 μg/24 hours with urinary sodium excretion >200 mmol/24 hours. Across the population, there were strong and significant associations between higher aldosterone excretion rate and higher urinary potassium excretion, higher angiotensin II-stimulated aldosterone, and lower plasma renin activity, suggesting a continuum of renin-independent aldosteronism and mineralocorticoid receptor activity. Autonomous aldosterone secretion that fulfilled confirmatory criteria for primary aldosteronism was detected in 29 participants (14%). Normotensives with evidence suggestive of confirmed primary aldosteronism had higher 24-hour urinary aldosterone excretion rate (20.2±12.2 versus 6.2±2.9 μg/24 hours; P<0.001) as expected, but also higher angiotensin II-stimulated aldosterone (12.4±8.6 versus 6.6±4.3 ng/dL; P<0.001) and lower 24-hour urinary sodium-to-potassium excretion (2.69±0.65 versus 3.69±1.50 mmol/mmol; P=0.001); however, there were no differences in age, aldosterone-to-renin ratio, blood pressure, or renal plasma flow between the 2 groups. These findings indicate a continuum of renin-independent aldosteronism and mineralocorticoid receptor activity in normotension that ranges from subtle to overtly dysregulated and autonomous. Longitudinal studies are needed to determine whether this spectrum of autonomous aldosterone secretion contributes to hypertension and cardiovascular disease.

Maternal corticosterone exposure in the mouse programs sex-specific renal adaptations in the renin-angiotensin-aldosterone system in 6-month offspring

Short‐term maternal corticosterone (Cort) administration at mid‐gestation in the mouse reduces nephron number in both sexes while programming renal and cardiovascular dysfunction in 12‐month male but not female offspring. The renal renin–angiotensin–aldosterone system (RAAS), functions in a sexually dimorphic manner to regulate both renal and cardiovascular physiology. This study aimed to identify if there are sex‐specific differences in basal levels of the intrarenal RAAS and to determine the impact of maternal Cort exposure on the RAAS in male and female offspring at 6 months of age. While intrarenal renin concentrations were higher in untreated females compared to untreated males, renal angiotensin II concentrations were higher in males than females. Furthermore, basal plasma aldosterone concentrations were greater in females than males. Cort exposed male but not female offspring had reduced water intake and urine excretion. Cort exposure increased renal renin concentrations and elevated mRNA expression of Ren1, Ace2, and Mas1 in male but not female offspring. In addition, male Cort exposed offspring had increased expression of the aldosterone receptor, Nr3c2 and renal sodium transporters. In contrast, Cort exposure increased Agtr1a mRNA levels in female offspring only. This study demonstrates that maternal Cort exposure alters key regulators of renal function in a sex‐specific manner at 6 months of life. These finding likely contribute to the disease outcomes in male but not female offspring in later life and highlights the importance of renal factors other than nephron number in the programming of renal and cardiovascular disease.

Hypotensive and Angiotensin-Converting Enzyme Inhibitory Activities of Eisenia fetida Extract in Spontaneously Hypertensive Rats

Objectives. This study aimed to investigate the antihypertensive effects of an Eisenia fetida extract (EFE) and its possible mechanisms in spontaneously hypertensive rats (SHR rats). Methods. Sixteen-week-old SHR rats and Wistar-Kyoto rats (WKY rats) were used in this study. Rats were, respectively, given EFE (EFE group), captopril (captopril group), or phosphate-buffered saline (PBS) (normal control group and SHR group) for 4 weeks. ACE inhibitory activity of EFE in vitro was determined. The systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured using a Rat Tail-Cuff Blood Pressure System. Levels of angiotensin II (Ang II), aldosterone (Ald), and 6-keto-prostaglandin F1 alpha (6-keto-PGF1α ) in plasma were determined by radioimmunoassay, and serum nitric oxide (NO) concentration was measured by Griess reagent systems. Results. EFE had marked ACE inhibitory activity in vitro (IC50 = 2.5 mg/mL). After the 4-week drug management, SHR rats in EFE group and in captopril group had lower SBP and DBP, lower levels of Ang II and Ald, and higher levels of 6-keto-PGF1α and NO than the SHR rats in SHR group. Conclusion. These results indicate that EFE has hypotensive effects in SHR rats and its effects might be associated with its ACE inhibitory activity.

Discovery of N-[5-(6-Chloro-3-cyano-1-methyl-1H-indol-2-yl)-pyridin-3-ylmethyl]-ethanesulfonamide, a Cortisol-Sparing CYP11B2 Inhibitor that Lowers Aldosterone in Human Subjects

Human clinical studies conducted with LCI699 established aldosterone synthase (CYP11B2) inhibition as a promising novel mechanism to lower arterial blood pressure. However, LCI699's low CYP11B1/CYP11B2 selectivity resulted in blunting of adrenocorticotropic hormone-stimulated cortisol secretion. This property of LCI699 prompted its development in Cushing's disease, but limited more extensive clinical studies in hypertensive populations, and provided an impetus for the search for cortisol-sparing CYP11B2 inhibitors. This paper summarizes the discovery, pharmacokinetics, and pharmacodynamic data in preclinical species and human subjects of the selective CYP11B2 inhibitor 8.

Adrenal Vein Sampling for Conn's Syndrome: Diagnosis and Clinical Outcomes

Adrenal vein sampling (AVS) is the gold standard test to determine unilateral causes of primary aldosteronism (PA). We have retrospectively characterized our experience with AVS including concordance of AVS results and imaging, and describe the approach for the PA patient in whom bilateral AVS is unsuccessful. We reviewed the medical records of 85 patients with PA and compared patients who were treated medically and surgically on pre-procedure presentation and post-treatment outcomes, and evaluated how technically unsuccessful AVS results were used in further patient management. Out of the 92 AVS performed in 85 patients, AVS was technically successful bilaterally in 58 (63%) of cases. Either unsuccessful AVS prompted a repeat AVS, or results from the contralateral side and from CT imaging were used to guide further therapy. Patients who were managed surgically with adrenalectomy had higher initial blood pressure and lower potassium levels compared with patients who were managed medically. Adrenalectomy results in significantly decreased blood pressure and normalization of potassium levels. AVS can identify surgically curable causes of PA, but can be technically challenging. When one adrenal vein fails to be cannulated, results from the contralateral vein can be useful in conjunction with imaging and clinical findings to suggest further management.

Progress in aldosteronism: a review of the prevalence of primary aldosteronism in pre-hypertension and hypertension

Primary aldosteronism (PA) secondary to excessive and/or autonomous aldosterone secretion from the renin-angiotensin system accounts for ∼10% of cases of hypertension and is primarily caused by bilateral adrenal hyperplasia (BAH) or aldosterone-producing adenomas (APAs). Although the diagnosis has traditionally been supported by low serum potassium levels, normokalaemic and even normotensive forms of PA have been identified expanding further the clinical phenotype. Moreover, recent evidence has shown that serum aldosterone correlates with increased blood pressure (BP) in the general population and even moderately raised aldosterone levels are linked to increased cardiovascular morbidity and mortality. In addition, aldosterone antagonists are effective in BP control even in patients without evidence of dysregulated aldosterone secretion. These findings indicate a higher prevalence of aldosterone excess among hypertensive patients than previously considered that could be attributed to disease heterogeneity, aldosterone level fluctuations related to an ACTH effect or inadequate sensitivity of current diagnostic means to identify apparent aldosterone excess. In addition, functioning aberrant receptors expressed in the adrenal tissue have been found in a subset of PA cases that could also be related to its pathogenesis. Recently a number of specific genetic alterations, mainly involving ion homeostasis across the membrane of zona glomerulosa, have been detected in ∼50% of patients with APAs. Although specific genotype/phenotype correlations have not been clearly identified, differential expression of these genetic alterations could also account for the wide clinical phenotype, variations in disease prevalence and performance of diagnostic tests. In the present review, we critically analyse the current means used to diagnose PA along with the role that ACTH, aberrant receptor expression and genetic alterations may exert, and provide evidence for an increased prevalence of aldosterone dysregulation in patients with essential hypertension and pre-hypertension.

On the pleotropic actions of mineralocorticoids

Classical effects of mineralocorticoids include stimulation of Na(+) reabsorption and K(+) secretion in the kidney and other epithelia including colon and several glands. Moreover, mineralocorticoids enhance the excretion of Mg(2+) and renal tubular H(+) secretion. The renal salt retention following mineralocorticoid excess leads to extracellular volume expansion and hypertension. The increase of blood pressure following mineralocorticoid excess is, however, not only the result of volume expansion but may result from stiff endothelial cell syndrome impairing the release of vasodilating nitric oxide. Beyond that, mineralocorticoids are involved in the regulation of a wide variety of further functions, including cardiac fibrosis, platelet activation, neuronal function and survival, inflammation as well as vascular and tissue fibrosis and calcification. Those functions are briefly discussed in this short introduction to the special issue. Beyond that, further contributions of this special issue amplify on mineralocorticoid-induced sodium appetite and renal salt retention, the role of mineralocorticoids in the regulation of acid-base balance, the involvement of aldosterone and its receptors in major depression, the mineralocorticoid stimulation of inflammation and tissue fibrosis and the effect of aldosterone on osteoinductive signaling and vascular calcification. Clearly, still much is to be learned about the various ramifications of mineralocorticoid-sensitive physiology and pathophysiology.

Primary aldosteronism in hypertensive patients: clinical implications and target therapy

BACKGROUND

The prevalence of primary aldosteronism (PA) in hypertensive patients varies according to diagnostic testing and ascertained normal cut-offs. The aim of this case-control study was to confirm the high prevalence of PA in a large hypertensive population and evaluate the antihypertensive effect of mineralocorticoid receptor antagonists (MRA) treatment.

MATERIAL AND METHODS

We investigated 327 hypertensive and 90 matched normotensive subjects with normal adrenal imaging. Serum aldosterone (ALD), active renin (REN) levels and aldosterone/active renin (ALD/REN) ratio were measured before and after a combined sodium chloride, fludrocortisone and dexamethasone suppression test (FDST). Post-FDST values were compared to cut-offs obtained from controls (post-FDST ALD 2·96 ng/dL and post-FDST ALD/REN 0·93 ng/dL/μU/mL). PA patients received MRA treatment.

RESULTS

By applying the combination of post-FDST ALD levels and ALD/REN ratio, 28·7% of the hypertensive patients had PA. There was a positive, albeit weak, correlation between systolic (SBP) and diastolic blood pressure (DBP) and ALD levels and/or ALD/REN ratio after the FDST (P < 0·0001). SBP was associated with a post-FDST ALD of 3·24 ng/dL and ALD/REN ratio of 0·90 ng/dL/μU/mL, whereas post-FDST ALD had an inverse association at serum K+ values of less than 3·9 mEq/L. MRA treatment in 69 PA patients, resulted in a significant reduction in the maximum SBP and DBP values (28 ± 15 and 14 ± 7 mmHg, respectively, P < 0·0001).

CONCLUSIONS

Using the FDST, an increased prevalence of PA in hypertensives was observed. Α significant blood pressure lowering effect was obtained with MRA treatment, implying that these agents may be beneficial in a significant number of hypertensive patients.

Increased aldosterone: mechanism of hypertension in obesity

The prevalence of both obesity and hypertension are increasing worldwide. Hypertension is a common consequence of obesity. Increased central adiposity is associated with increased aldosterone levels and blood pressure in human beings. A number of small studies have shown an association between obesity-mediated hypertension and mechanisms directly linked to increased levels of aldosterone. These studies have shown a trend toward relatively greater blood pressure reduction using aldosterone-receptor blockers compared with other classes of antihypertensive agents. Other than treatment for weight loss, treatment of hypertension with specific antihypertensive medications that block or reduce aldosterone action are appropriate in obese patients. Further research is needed to understand the exact role of the adipocyte in obesity-mediated hypertension.

Upregulation of store operated Ca channel Orai1, stimulation of Ca(2+) entry and triggering of cell membrane scrambling in platelets by mineralocorticoid DOCA

BACKGROUND/AIMS

Mineralocorticoid excess leads to vascular injury, which is partially due to hypertension but in addition involves increased concentration of cytosolic Ca(2+) concentration in platelets, key players in the pathophysiology of occlusive vascular disease. Mineralocorticoids are in part effective by rapid nongenomic mechanisms including phosphatidylinositide-3-kinase (PI3K) signaling, which involves activation of the serum & glucocorticoid inducible kinase (SGK) isoforms. SGK1 has in turn been shown to participate in the regulation of the pore forming Ca(2+) channel protein Orai1 in platelets. Orai1 accomplishes entry of Ca(2+), which is in turn known to trigger cell membrane scrambling. Platelets lack nuclei but are able to express protein by translation, which is stimulated by PI3K signaling. The present study explored whether the mineralocorticoid desoxycorticosterone acetate (DOCA) influences platelet Orai1 protein abundance, cytosolic Ca(2+)-activity ([Ca(2+)]i), phosphatidylserine abundance at the cell surface and/or cell volume.

METHODS

Orai1 protein abundance was estimated utilizing CF™488A conjugated antibodies, [Ca(2+)]i utilizing Fluo3-fluorescence, phosphatidylserine abundance utilizing FITC-labelled annexin V, and cell volume utilizing forward scatter in flow cytometry.

RESULTS

DOCA (10 µg/ml) treatment of murine platelets was followed by a significant increase of Orai1 protein abundance, [Ca(2+)]i, percentage of phosphatidylserine exposing platelets and platelet swelling. The effect on [Ca(2+)]i, phosphatidylserine abundance and cell volume were completely abrogated by addition of the specific SGK inhibitor EMD638683 (50 µM) CONCLUSIONS: The mineralocorticoid DOCA upregulates Orai1 protein abundance in the cell membrane, thus increasing [Ca(2+)]i and triggering phosphatidylserine abundance, effects paralleled by platelet swelling.

From bad behaviour to bad biology: pitfalls and promises in the management of resistant hypertension

Control rates for hypertension have dramatically improved during the past 2 decades-especially in Canada. However, hypertension remains one of the top risk factors for premature death globally. Furthermore, one-third of Canadians with hypertension have not obtained adequate blood pressure control. Most of these patients have resistant hypertension with uncontrolled blood pressure despite therapy. The etiology of resistant hypertension is multifactorial but includes both behavioural and biological factors. Among behavioural factors, nonadherence on the part of patients and especially clinical inertia on the part of health care professionals are contributing causes. An understanding of the root causes underlying the failure to control an individual's blood pressure is central to optimal subsequent management. Further advances in blood pressure control rates in this group of patients will depend on improvements in health care delivery systems and the further development of innovative therapies. Drugs combining multiple antihypertensive agents in a single pill and the development of new technologies to lower blood pressure, primarily by disruption of the sympathetic nervous system, have the potential to be useful strategies in this effort.