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Journal of the... 2020Amiloride is a potassium retaining diuretic and natriuretic which acts by reversibly blocking luminal epithelial sodium channels (ENaCs) in the late distal tubule and... (Review)
Review
Amiloride is a potassium retaining diuretic and natriuretic which acts by reversibly blocking luminal epithelial sodium channels (ENaCs) in the late distal tubule and collecting duct. Amiloride is indicated in oedematous states, and for potassium conservation adjunctive to thiazide or loop diuretics for hypertension, congestive heart failure and hepatic cirrhosis with ascites. Historical studies on its use in hypertension were poorly controlled and there is insufficient data on dose-response. It is clearly highly effective in combination with thiazide diuretics where it counteracts the adverse metabolic effects of the thiazides and its use in the Medical Research Council Trial of Older Hypertensive Patients, demonstrated convincing outcome benefits on stroke and coronary events. Recently it has been shown to be as effective as spironolactone in resistant hypertension but there is a real need to establish its potential role in the much larger number of patients with mild to moderate hypertension in whom there is a paucity of information with amiloride particularly across an extended dose range.
Topics: Amiloride; Animals; Clinical Trials as Topic; Diuretics; Humans; Hypertension
PubMed: 33234024
DOI: 10.1177/1470320320975893 -
Acta Physiologica (Oxford, England) May 2022Proteases are fundamental for a plethora of biological processes, including signalling and tissue remodelling, and dysregulated proteolytic activity can result in... (Review)
Review
Proteases are fundamental for a plethora of biological processes, including signalling and tissue remodelling, and dysregulated proteolytic activity can result in pathogenesis. In this review, we focus on a subclass of membrane-bound and soluble proteases that are defined as channel-activating proteases (CAPs), since they induce Na ion transport through an autocrine mechanism when co-expressed with the highly amiloride-sensitive epithelial sodium channel (ENaC) in Xenopus oocytes. These experiments first identified CAP1 (channel-activating protease 1, prostasin) followed by CAP2 (channel-activating protease 2, TMPRSS4) and CAP3 (channel-activating protease 3, matriptase) as in vitro mediators of ENaC current. Since then, more serine-, cysteine- and metalloproteases were confirmed as in vitro CAPs that potentially cleave and regulate ENaC, and thus this nomenclature was not further followed, but is accepted as functional term or alias. The precise mechanism of ENaC modulation by proteases has not been fully elucidated. Studies in organ-specific protease knockout models revealed evidence for their role in increasing ENaC activity, although the proteases responsible for ENaC activation are yet to be identified. We summarize recent findings in animal models of these CAPs with respect to their implication in ENaC activation. We discuss the consequences of dysregulated CAPs underlying epithelial phenotypes in pathophysiological conditions, and the role of selected protease inhibitors. We believe that these proteases may present interesting therapeutic targets for diseases with aberrant sodium homoeostasis.
Topics: Amiloride; Animals; Epithelial Sodium Channels; Ion Transport; Peptide Hydrolases; Sodium
PubMed: 35276025
DOI: 10.1111/apha.13811 -
The Journal of Clinical Investigation Jan 2024Mineralocorticoid excess commonly leads to hypertension (HTN) and kidney disease. In our study, we used single-cell expression and chromatin accessibility tools to...
Mineralocorticoid excess commonly leads to hypertension (HTN) and kidney disease. In our study, we used single-cell expression and chromatin accessibility tools to characterize the mineralocorticoid target genes and cell types. We demonstrated that mineralocorticoid effects were established through open chromatin and target gene expression, primarily in principal and connecting tubule cells and, to a lesser extent, in segments of the distal convoluted tubule cells. We examined the kidney-protective effects of steroidal and nonsteroidal mineralocorticoid antagonists (MRAs), as well as of amiloride, an epithelial sodium channel inhibitor, in a rat model of deoxycorticosterone acetate, unilateral nephrectomy, and high-salt consumption-induced HTN and cardiorenal damage. All antihypertensive therapies protected against cardiorenal damage. However, finerenone was particularly effective in reducing albuminuria and improving gene expression changes in podocytes and proximal tubule cells, even with an equivalent reduction in blood pressure. We noted a strong correlation between the accumulation of injured/profibrotic tubule cells expressing secreted posphoprotein 1 (Spp1), Il34, and platelet-derived growth factor subunit b (Pdgfb) and the degree of fibrosis in rat kidneys. This gene signature also showed a potential for classifying human kidney samples. Our multiomics approach provides fresh insights into the possible mechanisms underlying HTN-associated kidney disease, the target cell types, the protective effects of steroidal and nonsteroidal MRAs, and amiloride.
Topics: Rats; Humans; Animals; Mineralocorticoid Receptor Antagonists; Chromatin; Amiloride; Mineralocorticoids; Kidney; Hypertension; Kidney Diseases; Gene Expression Profiling
PubMed: 37906287
DOI: 10.1172/JCI157165 -
Journal of Hypertension Aug 2016
Topics: Amiloride; Diabetes Mellitus; Humans; Kidney; Sodium
PubMed: 27355999
DOI: 10.1097/HJH.0000000000001031 -
Cureus Jan 2021Diabetes insipidus (DI) is a disorder of water balance characterized by polyuria and polydipsia. It can occur due to genetic and acquired causes that affect the... (Review)
Review
Diabetes insipidus (DI) is a disorder of water balance characterized by polyuria and polydipsia. It can occur due to genetic and acquired causes that affect the secretion or action of arginine vasopressin (AVP) or antidiuretic hormone (ADH).Markedly increased thirst and urination are not only quite distressing but also increases the risk of volume depletion and hypernatremia in severe situations. A careful diagnosis of the type of DI and its etiology is based on careful clinical evaluation, measurement of urine and serum osmolality, and water deprivation test. Management includes the correction of any water deficit and the use of specific pharmacological agents, including desmopressin, thiazides, and amiloride.
PubMed: 33425560
DOI: 10.7759/cureus.12498 -
Frontiers in Physiology 2022
PubMed: 35173633
DOI: 10.3389/fphys.2022.831830