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Boder P, Mary S, Mark PB, Leiper J, Dominiczak AF, Padmanabhan S, Rampoldi L, Delles C. Mechanistic interactions of uromodulin with the thick ascending limb: perspectives in physiology and hypertension. J Hypertens 2021; 39:1490-1504. [PMID: 34187999 PMCID: PMC7611110 DOI: 10.1097/hjh.0000000000002861] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Hypertension is a significant risk factor for cardiovascular disease and mortality worldwide. The kidney is a major regulator of blood pressure and electrolyte homeostasis, with monogenic disorders indicating a link between abnormal ion transport and salt-sensitive hypertension. However, the association between salt and hypertension remains controversial. Thus, there is continued interest in deciphering the molecular mechanisms behind these processes. Uromodulin (UMOD) is the most abundant protein in the normal urine and is primarily synthesized by the thick ascending limb epithelial cells of the kidney. Genome-wide association studies have linked common UMOD variants with kidney function, susceptibility to chronic kidney disease and hypertension independent of renal excretory function. This review will discuss and provide predictions on the role of the UMOD protein in renal ion transport and hypertension based on current observational, biochemical, genetic, pharmacological and clinical evidence.
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Affiliation(s)
- Philipp Boder
- BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Sheon Mary
- BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Patrick B. Mark
- BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
| | - James Leiper
- BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Anna F. Dominiczak
- BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Sandosh Padmanabhan
- BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Luca Rampoldi
- Molecular Genetics of Renal Disorders Unit, Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Christian Delles
- BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
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Zhang J, Chen J, Chen Q, Chen J, Luo K, Pan L, Zhang Y, Dou W, Xing W. Can R 2 ' mapping evaluate hypoxia in renal ischemia reperfusion injury quantitatively? An experimental study. Magn Reson Med 2021; 86:974-983. [PMID: 33724527 DOI: 10.1002/mrm.28696] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 12/31/2020] [Accepted: 01/04/2021] [Indexed: 11/09/2022]
Abstract
PURPOSE To explore if R2 ' mapping can assess renal hypoxia in rabbits with ischemia reperfusion injury (IRI). METHODS Forty rabbits were randomly divided into 4 groups according to the clipping time: the sham group and 45 min, 60 min, and 75 min for the mild, moderate, and severe groups (with n = 10 each group), respectively. Intravenous furosemide (FU) was administered 24 h after IRI. All rabbits were performed 5 times (IRIpre , IRI24h , FU5min , FU12min , and FU24min ) with a 3.0 Tesla MR. The R2 ' values and the hypoxic scores were then recorded. The repeated measurement analysis of variance and Spearman correlation analysis was used for statistical analysis. RESULTS Compared to the baseline, the medullary R2 ' values increased significantly 24 h after the IRI (baseline 19.31 ± 1.21 s-1 , mild group 20.05 ± 1.26 s-1 , moderate group 25.38 ± 1.38 s-1 , and severe group 25.79 ± 1.10 s-1 ; each P < .001). FU led to a significant decrease in the medullary R2 ' value (sham group 11.17 ± 4.33 s-1 , mild group 7.80 ± 0.74 s-1 , moderate group 3.92 ± 0.28 s-1 , and severe group 3.82 ± 0.23 s-1 ; each P < .05). Quantitative hypoxic scores revealed significant differences among the 4 groups in the outer medulla (P < .001 each). The medullary R2 ' differences (before and after intravenous FU) were significantly correlated with the hypoxic scores, respectively (P < .001). CONCLUSION R2 ' mapping can evaluate the renal hypoxia in the procession of IRI in rabbits and might serve as a quantitative biomarker for IRI.
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Affiliation(s)
- Jinggang Zhang
- Department of Radiology, Third Affiliated Hospital of Soochow University, Changzhou, People's Republic of China
| | - Jie Chen
- Department of Radiology, Third Affiliated Hospital of Soochow University, Changzhou, People's Republic of China
| | - Qin Chen
- Department of Radiology, Third Affiliated Hospital of Soochow University, Changzhou, People's Republic of China
| | - Jing Chen
- Department of Radiology, Third Affiliated Hospital of Soochow University, Changzhou, People's Republic of China
| | - Kai Luo
- Department of Radiology, Third Affiliated Hospital of Soochow University, Changzhou, People's Republic of China
| | - Liang Pan
- Department of Radiology, Third Affiliated Hospital of Soochow University, Changzhou, People's Republic of China
| | - Yongcheng Zhang
- Department of Radiology, Third Affiliated Hospital of Soochow University, Changzhou, People's Republic of China
| | - Weiqiang Dou
- MR research China, GE Healthcare, Beijing, People's Republic of China
| | - Wei Xing
- Department of Radiology, Third Affiliated Hospital of Soochow University, Changzhou, People's Republic of China
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Papanicolaou KN, Ashok D, Liu T, Bauer TM, Sun J, Li Z, da Costa E, D'Orleans CC, Nathan S, Lefer DJ, Murphy E, Paolocci N, Foster DB, O'Rourke B. Global knockout of ROMK potassium channel worsens cardiac ischemia-reperfusion injury but cardiomyocyte-specific knockout does not: Implications for the identity of mitoKATP. J Mol Cell Cardiol 2020; 139:176-189. [PMID: 32004507 PMCID: PMC7849919 DOI: 10.1016/j.yjmcc.2020.01.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 01/16/2020] [Accepted: 01/23/2020] [Indexed: 01/29/2023]
Abstract
The renal-outer-medullary‑potassium (ROMK) channel, mutated in Bartter's syndrome, regulates ion exchange in kidney, but its extra-renal functions remain unknown. Additionally, ROMK was postulated to be the pore-forming subunit of the mitochondrial ATP-sensitive K+ channel (mitoKATP), a mediator of cardioprotection. Using global and cardiomyocyte-specific knockout mice (ROMK-GKO and ROMK-CKO respectively), we characterize the effects of ROMK knockout on mitochondrial ion handling, the response to pharmacological KATP channel modulators, and ischemia/reperfusion (I/R) injury. Mitochondria from ROMK-GKO hearts exhibited a lower threshold for Ca2+-triggered permeability transition pore (mPTP) opening but normal matrix volume changes during oxidative phosphorylation. Isolated perfused ROMK-GKO hearts exhibited impaired functional recovery and increased infarct size when I/R was preceded by an ischemic preconditioning (IPC) protocol. Because ROMK-GKO mice exhibited severe renal defects and cardiac remodeling, we further characterized ROMK-CKO hearts to avoid confounding systemic effects. Mitochondria from ROMK-CKO hearts had unchanged matrix volume responses during oxidative phosphorylation and still swelled upon addition of a mitoKATP opener, but exhibited a lower threshold for mPTP opening, similar to GKO mitochondria. Nevertheless, I/R induced damage was not exacerbated in ROMK-CKO hearts, either ex vivo or in vivo. Lastly, we examined the response of ROMK-CKO hearts to ex vivo I/R injury with or without IPC and found that IPC still protected these hearts, suggesting that cardiomyocyte ROMK does not participate significantly in the cardioprotective pathway elicited by IPC. Collectively, our findings from these novel strains of mice suggest that cardiomyocyte ROMK is not a central mediator of mitoKATP function, although it can affect mPTP activation threshold.
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Affiliation(s)
- Kyriakos N Papanicolaou
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Deepthi Ashok
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ting Liu
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Tyler M Bauer
- Cardiovascular Branch, NHLBI, NIH, 10 Center Drive, Bethesda, MD, USA
| | - Junhui Sun
- Cardiovascular Branch, NHLBI, NIH, 10 Center Drive, Bethesda, MD, USA
| | - Zhen Li
- Cardiovascular Center of Excellence, Louisiana State University (LSU) Health Sciences Center, New Orleans, LA, USA; Department of Pharmacology and Experimental Therapeutics, LSU Health Sciences Center, New Orleans, LA, USA
| | - Eduardo da Costa
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Charles Crepy D'Orleans
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Sara Nathan
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - David J Lefer
- Cardiovascular Center of Excellence, Louisiana State University (LSU) Health Sciences Center, New Orleans, LA, USA; Department of Pharmacology and Experimental Therapeutics, LSU Health Sciences Center, New Orleans, LA, USA
| | - Elizabeth Murphy
- Cardiovascular Branch, NHLBI, NIH, 10 Center Drive, Bethesda, MD, USA
| | - Nazareno Paolocci
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - D Brian Foster
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Brian O'Rourke
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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4
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Kim JM, Xu S, Guo X, Hu H, Dong K, Wang T. Urinary bladder hypertrophy characteristic of male ROMK Bartter's mice does not occur in female mice. Am J Physiol Regul Integr Comp Physiol 2017; 314:R334-R341. [PMID: 29092859 DOI: 10.1152/ajpregu.00315.2017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The renal outer medullary potassium channel (ROMK; Kir1.1) plays an important role in Na+ and K+ homeostasis. ROMK knockout (KO) mice show a similar phenotype to Bartter's syndrome of salt wasting and dehydration due to reduced Na-2Cl-K-cotransporter activity but not in ROMK1 KO mice. ROMK KO mice also show hydronephrosis; however, the mechanism of this phenotype has not been understood. We have previously demonstrated a gender-sex difference in hydronephrosis and PGE2 production in ROMK KO mice. In this study we compared the gender-sex difference in bladder hypertrophy and hydronephrosis in ROMK KO mice. The bladder weight, bladder capacity, and the thickness of urothelium in male ROMK KO showed average increased two to approximately fourfold greater than wild-type (WT) mice, but there was no difference in either female or ROMK1 KO mice. The thickness of the urothelium was 648.8 ± 33.2 µm vs. 302.7 ± 16.5 µm ( P < 0.001) and the detrusor muscle 1,940.7 ± 98.9 µm vs. 1,308.2 ± 102.1 µm ( P = 0.013), respectively, in 12-mo male ROMK KO mice compared with the same age WT mice. Western blotting detected ROMK expression at 45~48 kDa, and both ROMK1 and ROMK2 mRNA were detected by quantitative PCR in the bladder. Immunofluorescence staining showed ROMK stained in the bladder, ureter, and urethra in WT but not in KO. In addition, there was a correlation between the severity of hydronephrosis and the bladder weight in male but not in female ROMK KO mice. In conclusion, ROMK expressed in the urinary tract at both protein and mRNA levels; significant enlargement and hypertrophy of the bladder may contribute to hydronephrosis in male ROMK KO mice.
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Affiliation(s)
- Jun-Mo Kim
- Department of Cellular and Molecular Physiology, Yale University, School of Medicine , New Haven, Connecticut
| | - Shuhua Xu
- Department of Cellular and Molecular Physiology, Yale University, School of Medicine , New Haven, Connecticut
| | - Xiaoyun Guo
- Department of Cellular and Molecular Physiology, Yale University, School of Medicine , New Haven, Connecticut
| | - Haiyan Hu
- Department of Cellular and Molecular Physiology, Yale University, School of Medicine , New Haven, Connecticut
| | - Ke Dong
- Department of Cellular and Molecular Physiology, Yale University, School of Medicine , New Haven, Connecticut
| | - Tong Wang
- Department of Cellular and Molecular Physiology, Yale University, School of Medicine , New Haven, Connecticut
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Araujo M, Welch WJ, Zhou X, Sullivan K, Walsh S, Pasternak A, Wilcox CS. Inhibition of ROMK blocks macula densa tubuloglomerular feedback yet causes renal vasoconstriction in anesthetized rats. Am J Physiol Renal Physiol 2017; 312:F1120-F1127. [PMID: 28228405 DOI: 10.1152/ajprenal.00662.2016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 02/15/2017] [Accepted: 02/16/2017] [Indexed: 11/22/2022] Open
Abstract
The Na+-K+-2Cl- cotransporter (NKCC2) on the loop of Henle is the site of action of furosemide. Because outer medullary potassium channel (ROMK) inhibitors prevent reabsorption by NKCC2, we tested the hypothesis that ROMK inhibition with a novel selective ROMK inhibitor (compound C) blocks tubuloglomerular feedback (TGF) and reduces vascular resistance. Loop perfusion of either ROMK inhibitor or furosemide caused dose-dependent blunting of TGF, but the response to furosemide was 10-fold more sensitive (IC50 = 10-6 M for furosemide and IC50 = 10-5 M for compound C). During systemic infusion, both diuretics inhibited TGF, but ROMK inhibitor was 10-fold more sensitive (compound C: 63% inhibition; furosemide: 32% inhibition). Despite blockade of TGF, 1 h of constant systemic infusion of both diuretics reduced the glomerular filtration rate (GFR) and renal blood flow (RBF) by 40-60% and increased renal vascular resistance (RVR) by 100-200%. Neither diuretic altered blood pressure or hematocrit. Proximal tubule hydrostatic pressures (PPT) increased transiently with both diuretics (compound C: 56% increase; furosemide: 70% increase) but returned to baseline. ROMK inhibitor caused more natriuresis (3,400 vs. 1,600% increase) and calciuresis (1,200 vs. 800% increase) but less kaliuresis (33 vs. 167% increase) than furosemide. In conclusion, blockade of ROMK or Na+-K+-2Cl- transport inhibits TGF yet increases renal vascular resistance. The renal vasoconstriction was independent of volume depletion, blood pressure, TGF, or PPT.
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Affiliation(s)
- Magali Araujo
- Hypertension Research Center and Division of Nephrology and Hypertension, Georgetown University, Washington, District of Columbia; and
| | - William J Welch
- Hypertension Research Center and Division of Nephrology and Hypertension, Georgetown University, Washington, District of Columbia; and
| | - Xiaoyan Zhou
- Department of Cardiometabolic Diseases, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - Kathleen Sullivan
- Department of Cardiometabolic Diseases, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - Shawn Walsh
- Department of Cardiometabolic Diseases, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - Alexander Pasternak
- Department of Cardiometabolic Diseases, Merck & Company, Incorporated, Kenilworth, New Jersey
| | - Christopher S Wilcox
- Hypertension Research Center and Division of Nephrology and Hypertension, Georgetown University, Washington, District of Columbia; and
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6
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Abdel-Magid AF. Potential of Renal Outer Medullary Potassium (ROMK) Channel as Treatments for Hypertension and Heart Failure. ACS Med Chem Lett 2017; 8:9-10. [PMID: 28105264 DOI: 10.1021/acsmedchemlett.6b00457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2016] [Indexed: 11/30/2022] Open
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7
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Dong K, Yan Q, Lu M, Wan L, Hu H, Guo J, Boulpaep E, Wang W, Giebisch G, Hebert SC, Wang T. Romk1 Knockout Mice Do Not Produce Bartter Phenotype but Exhibit Impaired K Excretion. J Biol Chem 2016; 291:5259-69. [PMID: 26728465 DOI: 10.1074/jbc.m115.707877] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Indexed: 01/05/2023] Open
Abstract
Romk knock-out mice show a similar phenotype to Bartter syndrome of salt wasting and dehydration due to reduced Na-K-2Cl-cotransporter activity. At least three ROMK isoforms have been identified in the kidney; however, unique functions of any of the isoforms in nephron segments are still poorly understood. We have generated a mouse deficient only in Romk1 by selective deletion of the Romk1-specific first exon using an ES cell Cre-LoxP strategy and examined the renal phenotypes, ion transporter expression, ROMK channel activity, and localization under normal and high K intake. Unlike Romk(-/-) mice, there was no Bartter phenotype with reduced NKCC2 activity and increased NCC expression in Romk1(-/-) mice. The small conductance K channel (SK) activity showed no difference of channel properties or gating in the collecting tubule between Romk1(+/+) and Romk1(-/-) mice. High K intake increased SK channel number per patch and increased the ROMK channel intensity in the apical membrane of the collecting tubule in Romk1(+/+), but such regulation by high K intake was diminished with significant hyperkalemia in Romk1(-/-) mice. We conclude that 1) animal knockouts of ROMK1 do not produce Bartter phenotype. 2) There is no functional linking of ROMK1 and NKCC2 in the TAL. 3) ROMK1 is critical in response to high K intake-stimulated K(+) secretion in the collecting tubule.
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Affiliation(s)
- Ke Dong
- From the Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06520 and
| | - Qingshang Yan
- From the Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06520 and
| | - Ming Lu
- From the Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06520 and
| | - Laxiang Wan
- From the Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06520 and
| | - Haiyan Hu
- From the Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06520 and
| | - Junhua Guo
- From the Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06520 and
| | - Emile Boulpaep
- From the Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06520 and
| | - WenHui Wang
- the Department of Pharmacology, New York Medical College, Valhalla, New York 10595
| | - Gerhard Giebisch
- From the Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06520 and
| | - Steven C Hebert
- From the Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06520 and
| | - Tong Wang
- From the Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06520 and
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Huang CC, Chung CM, Hung SI, Pan WH, Leu HB, Huang PH, Chiu CC, Lin LY, Lin CC, Yang CY, Li SY, Chen YC, Wu TC, Lin SJ, Chen JW. Clinical and Genetic Factors Associated With Thiazide-Induced Hyponatremia. Medicine (Baltimore) 2015; 94:e1422. [PMID: 26313793 PMCID: PMC4602917 DOI: 10.1097/md.0000000000001422] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Thiazide diuretics are associated with an increased risk of hyponatremia. The aim of this study was to investigate possible predictors of thiazide-induced hyponatremia.A total of 48 patients admitted to the ward or to the emergency department due to severe thiazide-induced hyponatremia (Na < 125 mmol/L) were enrolled in our study as the case group. Another 211 hypertensive patients with normal sodium levels after treatment with thiazide diuretics were selected as the control group. Twelve tag single nucleotide polymorphism markers were selected from the Potassium Channel, Inwardly Rectifying Subfamily J, Member 1 (KCNJ1) gene: rs1231254, rs2238009, rs1148058, rs675482, rs673614, rs12795437, rs2855800, rs2509585, rs3016774, rs881333, rs4529890, and rs7116606. Clinical and genetic parameters between patients with thiazide-induced hyponatremia and the control group were compared. Logistic regression was used to analyze data.The patients with thiazide-induced hyponatremia were older (P < 0.001), predominantly female (P = 0.008), had a lower mean body mass index (BMI) (P < 0.001), and more commonly used angiotensin II receptor antagonist (P < 0.001) and spironolactone (P = 0.007) compared with the control groups. Analysis with multivariate logistic regression revealed that age (odds ratio [OR], 1.13; 95% confidence interval [CI], 1.08-1.19, P < 0.001), female gender (OR, 4.49; 95% CI, 1.54-13.11, P = 0.006), BMI (OR, 0.80; 95% CI, 0.69-0.93, P = 0.003), and KCNJ1 rs2509585 C/T or T/T polymorphisms (OR, 5.75; 95% CI, 1.25-26.45, P = 0.03) were independent predictors for thiazide-induced hyponatremia.Older female patients with lower BMIs and KCNJ1 rs2509585 C/T or T/T polymorphisms were more likely to develop thiazide-induced hyponatremia.
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Affiliation(s)
- Chin-Chou Huang
- From the Department of Medical Education (C-CH); Department of Medical Research (S-JL, J-WC); Division of Cardiology, Department of Medicine (C-CH, H-BL, P-HH, C-CC, T-CW, S-JL, J-WC); Healthcare and Management Center (H-BL); Division of Endocrinology and Metabolism, Department of Medicine (L-YL); Division of Nephrology, Department of Medicine (C-CL, C-YY, S-yL); Department of Emergency Medicine, Taipei Veterans General Hospital (Y-CC); Cardiovascular Research Center (C-CH, H-BL, P-HH, C-CC, T-CW, S-JL, J-WC); Institute of Pharmacology (C-CH, S-IH, L-YL, J-WC); Institute of Clinical Medicine, National Yang-Ming University (H-BL, P-HH, T-CW, S-JL); Institute of Biomedical Sciences, Academia Sinica (W-HP); Institute of Epidemiology, School of Public Health, National Taiwan University, Taipei (W-HP); Environment-Omics-Disease Research Centre, China Medical University Hospital (C-MC); Graduate Institute of Clinical Medical Science, China Medical University, Taichung (C-MC); and Institute of Population Health Science, National Health Research Institutes, Miaoli, Taiwan, R.O.C. (W-HP)
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9
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Horn S, Naidus E, Alper SL, Danziger J. Cesium-associated hypokalemia successfully treated with amiloride. Clin Kidney J 2015; 8:335-8. [PMID: 26034598 PMCID: PMC4440464 DOI: 10.1093/ckj/sfv017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Accepted: 02/26/2015] [Indexed: 12/12/2022] Open
Abstract
Self-treatment of cancer with cesium chloride, despite proven lack of efficacy, continues to produce serious adverse effects. Among these is hypokalemia predisposing to life-threatening arrhythmia. The mechanism of cesium-associated hypokalemia (CAH) has not been described. We report urinary potassium wasting responsive to amiloride therapy in a cancer patient with CAH, and discuss possible mechanisms.
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Affiliation(s)
- Sarah Horn
- Beth Israel Deaconess Medical Center , Harvard Medical School , Boston, MA , USA
| | - Elliot Naidus
- Beth Israel Deaconess Medical Center , Harvard Medical School , Boston, MA , USA
| | - Seth L Alper
- Beth Israel Deaconess Medical Center , Harvard Medical School , Boston, MA , USA
| | - John Danziger
- Beth Israel Deaconess Medical Center , Harvard Medical School , Boston, MA , USA
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10
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Cheng CJ, Sung CC, Huang CL, Lin SH. Inward-rectifying potassium channelopathies: new insights into disorders of sodium and potassium homeostasis. Pediatr Nephrol 2015; 30:373-83. [PMID: 24899236 DOI: 10.1007/s00467-014-2764-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 12/11/2013] [Accepted: 01/10/2014] [Indexed: 11/30/2022]
Abstract
Inward-rectifying potassium (Kir) channels allow more inward than outward potassium flux when channels are open in mammalian cells. At physiological resting membrane potentials, however, they predominantly mediate outward potassium flux and play important roles in regulating the resting membrane potential in diverse cell types and potassium secretion in the kidneys. Mutations of Kir channels cause human hereditary diseases collectively called Kir channelopathies, many of which are characterized by disorders of sodium and potassium homeostasis. Studies on these genetic Kir channelopathies have shed light on novel pathophysiological mechanisms, including renal sodium and potassium handling, potassium shifting in skeletal muscles, and aldosterone production in the adrenal glands. Here, we review several recent advances in Kir channels and their clinical implications in sodium and potassium homeostasis.
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Affiliation(s)
- Chih-Jen Cheng
- Department of Medicine, Division of Nephrology, Tri-Service General Hospital, National Defense Medical Center, No. 325, Section 2, Cheng-Kung Road, Neihu 114, Taipei, Taiwan
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11
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Girault A, Brochiero E. Evidence of K+ channel function in epithelial cell migration, proliferation, and repair. Am J Physiol Cell Physiol 2013; 306:C307-19. [PMID: 24196531 DOI: 10.1152/ajpcell.00226.2013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Efficient repair of epithelial tissue, which is frequently exposed to insults, is necessary to maintain its functional integrity. It is therefore necessary to better understand the biological and molecular determinants of tissue regeneration and to develop new strategies to promote epithelial repair. Interestingly, a growing body of evidence indicates that many members of the large and widely expressed family of K(+) channels are involved in regulation of cell migration and proliferation, key processes of epithelial repair. First, we briefly summarize the complex mechanisms, including cell migration, proliferation, and differentiation, engaged after epithelial injury. We then present evidence implicating K(+) channels in the regulation of these key repair processes. We also describe the mechanisms whereby K(+) channels may control epithelial repair processes. In particular, changes in membrane potential, K(+) concentration, cell volume, intracellular Ca(2+), and signaling pathways following modulation of K(+) channel activity, as well as physical interaction of K(+) channels with the cytoskeleton or integrins are presented. Finally, we discuss the challenges to efficient, specific, and safe targeting of K(+) channels for therapeutic applications to improve epithelial repair in vivo.
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Affiliation(s)
- Alban Girault
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Quebec, Canada; and
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