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1.
[Antifibrotic renal role of mineralcorticoid receptor antagonists].
Ocello, A, La Rosa, S, Fiorini, F, Randone, S, Maccarrone, R, Battaglia, G, Granata, A
Giornale italiano di nefrologia : organo ufficiale della Societa italiana di nefrologia. 2019;(4)
Abstract
Cardiovascular and renal diseases are one of the main health problems in all industrialized countries. Their incidence is constantly increasing due to the aging of the population and the greater prevalence of obesity and type 2 diabetes. Clinical evidence suggests that aldosterone and the activation of mineralocorticoid receptors (MR) have a role in the pathophysiology of cardiovascular and renal diseases. Moreover, clinical studies demonstrate the benefits of mineralocorticoid receptor antagonists (MRAs) on mortality and progression of heart and kidney disease. In addition to renal effects on body fluid homeostasis, aldosterone has multiple extrarenal effects including the induction of inflammation, vascular rigidity, collagen formation and stimulation of fibrosis. Given the fundamental role of MR activation in renal and cardiac fibrosis, effective and selective blocking of the signal with MRAs can be used in the clinical practice to prevent or slow down the progression of heart and kidney diseases. The aim of the present work is to review the role of MRAs in light of the new evidence as well as its potential use as an antifibrotic in chronic kidney disease (CKD). The initial clinical results suggest that MRAs are potentially useful in treating patients with chronic kidney disease, particularly in cases of diabetic nephropathy. We don't yet have efficacy and safety data on the progression of kidney disease up to the end stage (ESRD) and filling this gap represents an important target for future trials.
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Effectiveness of Thermal Ablation for Aldosterone-Producing Adrenal Adenoma: A Systematic Review and Meta-Analysis of Clinical and Biochemical Parameters.
Liang, KW, Jahangiri, Y, Tsao, TF, Tyan, YS, Huang, HH
Journal of vascular and interventional radiology : JVIR. 2019;(9):1335-1342.e1
Abstract
PURPOSE To assess the effectiveness of thermal ablation for aldosterone-producing adrenal adenoma. MATERIALS AND METHODS A systematic search of the PubMed and CINAHL databases was performed to identify studies of thermal ablation for adrenal adenomas. Random effects meta-analysis models were used to compare pre- and post-treatment values of the following outcomes: systolic blood pressure (SBP), diastolic blood pressure (DBP), use of antihypertensive medications, and biochemical parameters (plasma aldosterone levels, aldosterone-to-renin ratio, and potassium levels). The rate of hypertension (HTN) resolution and improvement were also evaluated. RESULTS A total of 89 patients from 7 studies were included in the analysis. The mean postablation follow-up duration was 45.8 months. Pooled data analysis revealed a statistically significant decrease in SBP (-29.06 mm Hg; 95% confidence interval [CI], -33.93 to -24.19), DBP (-16.03 mm Hg; 95% CI, -18.33 to -13.73), and the number of antihypertensive medications used (-1.43; 95% CI, -1.97 to -0.89) after ablation. Biochemical parameters had returned to normal ranges after ablation in all studies. The cumulative rate of resolution or improvement in HTN status was 75.3%. On metaregression analysis, there was no statistically significant association between postablation blood pressure changes or serum aldosterone levels and study follow-up duration. CONCLUSIONS Thermal ablation for aldosterone-producing adrenal adenoma can be effective in controlling blood pressure, reducing the need for antihypertensive medications, and normalizing hormone secretion. Further higher-quality evidence is needed to confirm these results.
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3.
Low-Renin Hypertension.
Athimulam, S, Lazik, N, Bancos, I
Endocrinology and metabolism clinics of North America. 2019;(4):701-715
Abstract
Low-renin hypertension affects 30% of hypertensive patients. Primary hyperaldosteronism presents with low renin and aldosterone excess. Low-renin, low-aldosterone hypertension represents a wide spectrum of disorders that includes essential low-renin hypertension, hereditary forms of hypertension, and hypertension secondary to endogenous or exogenous factors. This review addresses the different conditions that present with low-renin hypertension, discussing an appropriate diagnostic approach and highlighting the genetic subtypes within familial forms.
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Influence of Sodium Citrate Supplementation after Dehydrating Exercise on Responses of Stress Hormones to Subsequent Endurance Cycling Time-Trial in the Heat.
Suvi, S, Mooses, M, Timpmann, S, Medijainen, L, Unt, E, Ööpik, V
Medicina (Kaunas, Lithuania). 2019;(4)
Abstract
Background and objectives: In temperate environments, acute orally induced metabolic alkalosis alleviates exercise stress, as reflected in attenuated stress hormone responses to relatively short-duration exercise bouts. However, it is unknown whether the same phenomenon occurs during prolonged exercise in the heat. This study was undertaken with aim to test the hypothesis that ingestion of an alkalizing substance (sodium citrate; CIT) after dehydrating exercise would decrease blood levels of stress hormones during subsequent 40 km cycling time-trial (TT) in the heat. Materials and Methods: Male non-heat-acclimated athletes (n = 20) lost 4% of body mass by exercising in the heat. Then, during a 16 h recovery period prior to TT in a warm environment (32 °C), participants ate the prescribed food and ingested CIT (600 mg·kg-1) or placebo (PLC) in a double-blind, randomized, crossover manner with 7 days between the two trials. Blood aldosterone, cortisol, prolactin and growth hormone concentrations were measured before and after TT. Results: Total work performed during TT was similar in the two trials (p = 0.716). In CIT compared to PLC trial, lower levels of aldosterone occurred before (72%) and after (39%) TT (p ˂ 0.001), and acute response of aldosterone to TT was blunted (29%, p ˂ 0.001). Lower cortisol levels in CIT than in PLC trial occurred before (13%, p = 0.039) and after TT (14%, p = 0.001), but there were no between-trial differences in the acute responses of cortisol, prolactin or growth hormone to TT, or in concentrations of prolactin and growth hormone before or after TT (in all cases p > 0.05). Conclusions: Reduced aldosterone and cortisol levels after TT and blunted acute response of aldosterone to TT indicate that CIT ingestion during recovery after dehydrating exercise may alleviate stress during the next hard endurance cycling bout in the heat.
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5.
Aldosterone as a mediator of severity in retinal vascular disease: Evidence and potential mechanisms.
Allingham, MJ, Mettu, PS, Cousins, SW
Experimental eye research. 2019;:107788
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Abstract
Diabetic retinopathy (DR) and retinal vein occlusion (RVO) are the two most common retinal vascular diseases and are major causes of vision loss and blindness worldwide. Recent and ongoing development of medical therapies including anti-vascular endothelial growth factor and corticosteroid drugs for treatment of these diseases have greatly improved the care of afflicted patients. However, severe manifestations of retinal vascular disease result in persistent macular edema, progressive retinal ischemia and incomplete visual recovery. Additionally, choroidal vascular diseases including neovascular age-related macular degeneration (NVAMD) and central serous chorioretinopathy (CSCR) cause vision loss for which current treatments are incompletely effective in some cases and highly burdensome in others. In recent years, aldosterone has gained attention as a contributor to the various deleterious effects of retinal and choroidal vascular diseases via a variety of mechanisms in several retinal cell types. The following is a review of the role of aldosterone in retinal and choroidal vascular diseases as well as our current understanding of the mechanisms by which aldosterone mediates these effects.
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Clinical and biochemical outcomes after adrenalectomy and medical treatment in patients with unilateral primary aldosteronism.
Katabami, T, Fukuda, H, Tsukiyama, H, Tanaka, Y, Takeda, Y, Kurihara, I, Ito, H, Tsuiki, M, Ichijo, T, Wada, N, et al
Journal of hypertension. 2019;(7):1513-1520
Abstract
OBJECTIVES Current clinical guidelines of primary aldosteronism recommend adrenalectomy (AdX) for unilateral primary aldosteronism based on the studies showing the potential superiority of AdX over the medical treatment. However, since most medically treated cases consisted of bilateral primary aldosteronism and all surgically treated cases consisted of unilateral primary aldosteronism, the different subtype of primary aldosteronism could be a bias for their effects. This study compared the effects of AdX and medical therapy in patients with unilateral primary aldosteronism confirmed by adrenal vein sampling. METHODS Of the 339 patients with unilateral primary aldosteronism in the Japan Primary Pldosteronism Study data base, unilateral AdX and treatment with mineral corticoid receptor antagonists (MRAs) was done in 276 patients (AdX group) and in 63 patients (MRAs group), respectively. The effects were compared by the clinical (improvement of blood pressure) and biochemical outcomes (improvement of hypokalemia). RESULTS At baseline, use of potassium replacement, plasma aldosterone concentration, aldosterone-to-renin ratio, estimated glomerular filtration rate, and prevalence of adrenal mass on imaging were higher in the AdX group than in the MRAs group. At 6 months after commencement of specific treatment for primary aldosteronism, clinical outcome and biochemical outcome in the AdX group were superior than those in the MRAs group. The difference of the outcome between the two groups were the case even after adjusting for the different clinical backgrounds in the two groups before the specific treatment. CONCLUSION Our study provides evidence that AdX is the first choice of treatment in the patients with unilateral primary aldosteronism in terms of clinical and biochemical outcome.
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Role of Aldosterone in Renal Fibrosis.
Shrestha, A, Che, RC, Zhang, AH
Advances in experimental medicine and biology. 2019;:325-346
Abstract
Aldosterone is a mineralocorticoid hormone, as its main renal effect has been considered as electrolyte and water homeostasis in the distal tubule, thus maintaining blood pressure and extracellular fluid homeostasis through the activation of mineralocorticoid receptor (MR) in epithelial cells. However, over the past decade, numerous studies have documented the significant role of aldosterone in the progression of chronic kidney disease (CKD) which has become a subject of interest. It is being studied that aldosterone can affect cardiovascular and renal system, thereby contributing to tissue inflammation, injury, glomerulosclerosis, and interstitial fibrosis. Aldosterone acts on renal vessels, renal cells (glomerular mesangial cells, podocytes, vascular smooth muscle cells, tubular epithelial cells, and interstitial fibroblasts), and infiltrating inflammatory cells, inducing reactive oxygen species (ROS) production, upregulated epithelial growth factor receptor (EGFR), and type 1 angiotensin (AT1) receptor expressions, and activating nuclear factor kappa B (NF-κB), activator protein-1 (AP-1), and EGFR to further promote cell proliferation, apoptosis, and proliferation. Phenotypic transformation of epithelial cells stimulates the expression of transforming growth factor-β (TGF-β), connective tissue growth factor (CTGF), osteopontin (OPN), and plasminogen activator inhibitor-1 (PAI-1), eventually leading to renal fibrosis. MR antagonisms are related to inhibition of aldosterone-mediated pro-inflammatory and pro-fibrotic effect. In this review, we will summarize the important role of aldosterone in the pathogenesis of renal injury and fibrosis, emphasizing on its multiple underlying mechanisms and advances in aldosterone research along with the potential therapeutics for targeting MR in a renal fibrosis.
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Paracrine Regulation of Aldosterone Secretion in Physiological and Pathophysiological Conditions.
Lefebvre, H, Duparc, C, Naccache, A, Lopez, AG, Castanet, M, Louiset, E
Vitamins and hormones. 2019;:303-339
Abstract
Aldosterone secretion by the zona glomerulosa of the adrenal cortex is controlled by circulating factors including the renin angiotensin system (RAS) and potassium. Mineralocorticoid production is also regulated through an autocrine/paracrine mechanism by a wide variety of bioactive signals released in the vicinity of adrenocortical cells by chromaffin cells, nerve endings, cells of the immune system, endothelial cells and adipocytes. These regulatory factors include conventional neurotransmitters and neuropeptides. Their physiological role in the control of aldosterone secretion is not fully understood, but it is likely that they participate in the RAS-independent regulation of zona glomerulosa cells. Interestingly, recent observations indicate that autocrine/paracrine processes are involved in the pathophysiology of primary aldosteronism. The intraadrenal regulatory systems observed in aldosterone-producing adenomas (APA), although globally similar to those occurring in the normal adrenal gland, harbor alterations at different levels, which tend to strengthen the potency of paracrine signals to activate aldosterone secretion. Enhancement of paracrine stimulatory tone may participate to APA expansion and aldosterone hypersecretion together with somatic mutations of driver genes which activate the calcium signaling pathway and subsequently aldosterone synthase expression. Intraadrenal regulatory mechanisms represent thus promising pharmacological targets for the treatment of primary aldosteronism.
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Angiotensin II and aldosterone in retinal vasculopathy and inflammation.
Wilkinson-Berka, JL, Suphapimol, V, Jerome, JR, Deliyanti, D, Allingham, MJ
Experimental eye research. 2019;:107766
Abstract
Angiotensin II and aldosterone are the main effectors of the renin-angiotensin aldosterone system (RAAS) and have a central role in hypertension as well as cardiovascular and renal disease. The localization of RAAS components within the retina has led to studies investigating the roles of angiotensin II, aldosterone and the counter regulatory arm of the pathway in vision-threatening retinopathies. This review will provide a brief overview of RAAS components as well as the vascular pathology that develops in the retinal diseases, retinopathy of prematurity, diabetic retinopathy and neovascular age-related macular degeneration. The review will discuss pre-clinical and clinical evidence that modulation of the RAAS alters the development of vasculopathy and inflammation in the aforementioned retinopathies, as well as the emerging role of aldosterone and the mineralocorticoid receptor in central serous chorioretinopathy.
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The Mechanisms of Actions of Aldosterone and its Antagonists in Cardiovascular Disease.
Pantelidis, P, Sideris, M, Viigimaa, M, Avranas, K, Deligkaris, P, Zografou, I, Lovic, D
Current pharmaceutical design. 2018;(46):5491-5499
Abstract
BACKGROUND Aldosterone, through its actions on Mineralcorticosteroid Receptors (MR), controls fluid and electrolyte balance, but also exerts various direct deleterious actions on the vasculature. A number of aldosterone antagonists have been manufactured to reverse these effects. OBJECTIVE A comprehensive review of the underlying mechanisms of the actions of aldosterone and its antagonists in cardiovascular disease. METHOD The relevant studies indexed in PubMed, Scopus and Google Scholar databases, published from 2003 to May 2018 were identified and reported. RESULTS Aldosterone binds to MR, activating them as intracellular transcription factors. Moreover, aldosterone, through its actions on MR, as well as on another not fully explored class of receptors, triggers several signaling pathways that produce rapid, non-genomic actions. In the vasculature, all these changes favor the establishment of inflammation and cardiovascular dysfunction, which, in turn, lead to or exacerbate various cardiovascular diseases. Mineralcorticosteroid Antagonists (MRA) are compounds that antagonize the action of aldosterone on MR. Spironolactone was the first steroidal MRA to be commercially used. It showed beneficial clinical results, but also a number of adverse effects. The next generation of steroidal MRA, exhibited lower potency but did not induce many of these adverse reactions, due to their high selectivity for MR. The third generation of MRA compromises the newly introduced non-steroidal MRA, which have a completely different chemical structure, they induce different and more drastic changes to MR, they are much more specific and currently under clinical trials. CONCLUSION New MRA, which block the aldosterone induced pathways in the vasculature, hold promising results for the treatment of cardiovascular disease.