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Mutchler SM, Hasan M, Murphy CP, Baty CJ, Boyd-Shiwarski C, Kirabo A, Kleyman TR. Dietary sodium alters aldosterone's effect on renal sodium transporter expression and distal convoluted tubule remodelling. J Physiol 2024; 602:967-987. [PMID: 38294810 PMCID: PMC10939779 DOI: 10.1113/jp284041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 12/21/2023] [Indexed: 02/01/2024] Open
Abstract
Aldosterone is responsible for maintaining volume and potassium homeostasis. Although high salt consumption should suppress aldosterone production, individuals with hyperaldosteronism lose this regulation, leading to a state of high aldosterone despite dietary sodium consumption. The present study examines the effects of elevated aldosterone, with or without high salt consumption, on the expression of key Na+ transporters and remodelling in the distal nephron. Epithelial sodium channel (ENaC) α-subunit expression was increased with aldosterone regardless of Na+ intake. However, ENaC β- and γ-subunits unexpectedly increased at both a transcript and protein level with aldosterone when high salt was present. Expression of total and phosphorylated Na+ Cl- cotransporter (NCC) significantly increased with aldosterone, in association with decreased blood [K+ ], but the addition of high salt markedly attenuated the aldosterone-dependent NCC increase, despite equally severe hypokalaemia. We hypothesized this was a result of differences in distal convoluted tubule length when salt was given with aldosterone. Imaging and measurement of the entire pNCC-positive tubule revealed that aldosterone alone caused a shortening of this segment, although the tubule had a larger cross-sectional diameter. This was not true when salt was given with aldosterone because the combination was associated with a lengthening of the tubule in addition to increased diameter, suggesting that differences in the pNCC-positive area are not responsible for differences in NCC expression. Together, our results suggest the actions of aldosterone, and the subsequent changes related to hypokalaemia, are altered in the presence of high dietary Na+ . KEY POINTS: Aldosterone regulates volume and potassium homeostasis through effects on transporters in the kidney; its production can be dysregulated, preventing its suppression by high dietary sodium intake. Here, we examined how chronic high sodium consumption affects aldosterone's regulation of sodium transporters in the distal nephron. Our results suggest that high sodium consumption with aldosterone is associated with increased expression of all three epithelial sodium channel subunits, rather than just the alpha subunit. Aldosterone and its associated decrease in blood [K+ ] lead to an increased expression of Na-Cl cotransporter (NCC); the addition of high sodium consumption with aldosterone partially attenuates this NCC expression, despite similarly low blood [K+ ]. Upstream kinase regulators and tubule remodelling do not explain these results.
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Affiliation(s)
| | | | - Carolyn P Murphy
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Catherine J Baty
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | | | - Annet Kirabo
- Division of Clinical Pharmacology, Department of Medicine, and Department of Molecular Physiology and Biophysics Vanderbilt University, Nashville, TN, USA
| | - Thomas R Kleyman
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
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2
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Meier S, Grundland A, Dobrev D, Volders PG, Heijman J. In silico analysis of the dynamic regulation of cardiac electrophysiology by K v 11.1 ion-channel trafficking. J Physiol 2023; 601:2711-2731. [PMID: 36752166 PMCID: PMC10313819 DOI: 10.1113/jp283976] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 01/30/2023] [Indexed: 02/09/2023] Open
Abstract
Cardiac electrophysiology is regulated by continuous trafficking and internalization of ion channels occurring over minutes to hours. Kv 11.1 (also known as hERG) underlies the rapidly activating delayed-rectifier K+ current (IKr ), which plays a major role in cardiac ventricular repolarization. Experimental characterization of the distinct temporal effects of genetic and acquired modulators on channel trafficking and gating is challenging. Computer models are instrumental in elucidating these effects, but no currently available model incorporates ion-channel trafficking. Here, we present a novel computational model that reproduces the experimentally observed production, forward trafficking, internalization, recycling and degradation of Kv 11.1 channels, as well as their modulation by temperature, pentamidine, dofetilide and extracellular K+ . The acute effects of these modulators on channel gating were also incorporated and integrated with the trafficking model in the O'Hara-Rudy human ventricular cardiomyocyte model. Supraphysiological dofetilide concentrations substantially increased Kv 11.1 membrane levels while also producing a significant channel block. However, clinically relevant concentrations did not affect trafficking. Similarly, severe hypokalaemia reduced Kv 11.1 membrane levels based on long-term culture data, but had limited effect based on short-term data. By contrast, clinically relevant elevations in temperature acutely increased IKr due to faster kinetics, while after 24 h, IKr was decreased due to reduced Kv 11.1 membrane levels. The opposite was true for lower temperatures. Taken together, our model reveals a complex temporal regulation of cardiac electrophysiology by temperature, hypokalaemia, and dofetilide through competing effects on channel gating and trafficking, and provides a framework for future studies assessing the role of impaired trafficking in cardiac arrhythmias. KEY POINTS: Kv 11.1 channels underlying the rapidly activating delayed-rectifier K+ current are important for ventricular repolarization and are continuously shuttled from the cytoplasm to the plasma membrane and back over minutes to hours. Kv 11.1 gating and trafficking are modulated by temperature, drugs and extracellular K+ concentration but experimental characterization of their combined effects is challenging. Computer models may facilitate these analyses, but no currently available model incorporates ion-channel trafficking. We introduce a new two-state ion-channel trafficking model able to reproduce a wide range of experimental data, along with the effects of modulators of Kv 11.1 channel functioning and trafficking. The model reveals complex dynamic regulation of ventricular repolarization by temperature, extracellular K+ concentration and dofetilide through opposing acute (millisecond) effects on Kv 11.1 gating and long-term (hours) modulation of Kv 11.1 trafficking. This in silico trafficking framework provides a tool to investigate the roles of acute and long-term processes on arrhythmia promotion and maintenance.
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Affiliation(s)
- Stefan Meier
- Department of Cardiology, Cardiovascular Research Institute Maastricht (CARIM), Faculty of Health, Medicine, and Life Sciences, Maastricht University and Maastricht University Medical Center+, Maastricht, The Netherlands
| | - Adaïa Grundland
- Department of Cardiology, Cardiovascular Research Institute Maastricht (CARIM), Faculty of Health, Medicine, and Life Sciences, Maastricht University and Maastricht University Medical Center+, Maastricht, The Netherlands
- Department of Data Science and Knowledge Engineering, Faculty of Science and Engineering, Maastricht University, Maastricht, The Netherlands
| | - Dobromir Dobrev
- Institute of Pharmacology, West German Heart and Vascular Center, University of Duisburg-Essen, Essen, Germany
- Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Medicine and Research Center, Montreal Heart Institute and Université de Montréal, Montréal, Quebec, Canada
| | - Paul G.A. Volders
- Department of Cardiology, Cardiovascular Research Institute Maastricht (CARIM), Faculty of Health, Medicine, and Life Sciences, Maastricht University and Maastricht University Medical Center+, Maastricht, The Netherlands
| | - Jordi Heijman
- Department of Cardiology, Cardiovascular Research Institute Maastricht (CARIM), Faculty of Health, Medicine, and Life Sciences, Maastricht University and Maastricht University Medical Center+, Maastricht, The Netherlands
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3
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Stavniichuk A, Pyrshev K, Zaika O, Tomilin VN, Kordysh M, Lakk M, Križaj D, Pochynyuk O. TRPV4 expression in the renal tubule is necessary for maintaining whole body K + homeostasis. Am J Physiol Renal Physiol 2023; 324:F603-F616. [PMID: 37141145 PMCID: PMC10281785 DOI: 10.1152/ajprenal.00278.2022] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 04/26/2023] [Accepted: 04/30/2023] [Indexed: 05/05/2023] Open
Abstract
The Ca2+-permeable transient receptor potential vanilloid type 4 (TRPV4) channel serves as the sensor of tubular flow, thus being well suited to govern mechanosensitive K+ transport in the distal renal tubule. Here, we directly tested whether the TRPV4 function is significant in affecting K+ balance. We used balance metabolic cage experiments and systemic measurements with different K+ feeding regimens [high (5% K+), regular (0.9% K+), and low (<0.01% K+)] in newly created transgenic mice with selective TRPV4 deletion in the renal tubule (TRPV4fl/fl-Pax8Cre) and their littermate controls (TRPV4fl/fl). Deletion was verified by the absence of TRPV4 protein expression and lack of TRPV4-dependent Ca2+ influx. There were no differences in plasma electrolytes, urinary volume, and K+ levels at baseline. In contrast, plasma K+ levels were significantly elevated in TRPV4fl/fl-Pax8Cre mice on high K+ intake. K+-loaded knockout mice exhibited lower urinary K+ levels than TRPV4fl/fl mice, which was accompanied by higher aldosterone levels by day 7. Moreover, TRPV4fl/fl-Pax8Cre mice had more efficient renal K+ conservation and higher plasma K+ levels in the state of dietary K+ deficiency. H+-K+-ATPase levels were significantly increased in TRPV4fl/fl-Pax8Cre mice on a regular diet and especially on a low-K+ diet, pointing to augmented K+ reabsorption in the collecting duct. Consistently, we found a significantly faster intracellular pH recovery after intracellular acidification, as an index of H+-K+-ATPase activity, in split-opened collecting ducts from TRPV4fl/fl-Pax8Cre mice. In summary, our results demonstrate an indispensable prokaliuretic role of TRPV4 in the renal tubule in controlling K+ balance and urinary K+ excretion during variations in dietary K+ intake. NEW & NOTEWORTHY The mechanoactivated transient receptor potential vanilloid type 4 (TRPV4) channel is expressed in distal tubule segments, where it controls flow-dependent K+ transport. Global TRPV4 deficiency causes impaired adaptation to variations in dietary K+ intake. Here, we demonstrate that renal tubule-specific TRPV4 deletion is sufficient to recapitulate the phenotype by causing antikaliuresis and higher plasma K+ levels in both states of K+ load and deficiency.
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Affiliation(s)
- Anna Stavniichuk
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center, Houston, Texas, United States
| | - Kyrylo Pyrshev
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center, Houston, Texas, United States
| | - Oleg Zaika
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center, Houston, Texas, United States
| | - Viktor N Tomilin
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center, Houston, Texas, United States
| | - Mariya Kordysh
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center, Houston, Texas, United States
| | - Monika Lakk
- Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, Salt Lake City, Utah, United States
| | - David Križaj
- Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, Salt Lake City, Utah, United States
| | - Oleh Pochynyuk
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center, Houston, Texas, United States
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Murillo-de-Ozores AR, Carbajal-Contreras H, Magaña-Ávila GR, Valdés R, Grajeda-Medina LI, Vázquez N, Zariñán T, López-Saavedra A, Sharma A, Lin DH, Wang WH, Delpire E, Ellison DH, Gamba G, Castañeda-Bueno M. Multiple molecular mechanisms are involved in the activation of the kidney sodium-chloride cotransporter by hypokalemia. Kidney Int 2022; 102:1030-1041. [PMID: 35870644 PMCID: PMC10411384 DOI: 10.1016/j.kint.2022.06.027] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 05/30/2022] [Accepted: 06/23/2022] [Indexed: 12/14/2022]
Abstract
Low potassium intake activates the kidney sodium-chloride cotransporter (NCC) whose phosphorylation and activity depend on the With-No-Lysine kinase 4 (WNK4) that is inhibited by chloride binding to its kinase domain. Low extracellular potassium activates NCC by decreasing intracellular chloride thereby promoting chloride dissociation from WNK4 where residue L319 of WNK4 participates in chloride coordination. Since the WNK4-L319F mutant is constitutively active and chloride-insensitive in vitro, we generated mice harboring this mutation that displayed slightly increased phosphorylated NCC and mild hyperkalemia when on a 129/sv genetic background. On a low potassium diet, upregulation of phosphorylated NCC was observed, suggesting that in addition to chloride sensing by WNK4, other mechanisms participate which may include modulation of WNK4 activity and degradation by phosphorylation of the RRxS motif in regulatory domains present in WNK4 and KLHL3, respectively. Increased levels of WNK4 and kidney-specific WNK1 and phospho-WNK4-RRxS were observed in wild-type and WNK4L319F/L319F mice on a low potassium diet. Decreased extracellular potassium promoted WNK4-RRxS phosphorylation in vitro and ex vivo as well. These effects might be secondary to intracellular chloride depletion, as reduction of intracellular chloride in HEK293 cells increased phospho-WNK4-RRxS. Phospho-WNK4-RRxS levels were increased in mice lacking the Kir5.1 potassium channel, which presumably have decreased distal convoluted tubule intracellular chloride. Similarly, phospho-KLHL3 was modulated by changes in intracellular chloride in HEK293 cells. Thus, our data suggest that multiple chloride-regulated mechanisms are responsible for NCC upregulation by low extracellular potassium.
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Affiliation(s)
- Adrián R Murillo-de-Ozores
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan, Mexico City; Faculty of Medicine, Universidad Nacional Autónoma de México, Coyoacan, Mexico City
| | - Héctor Carbajal-Contreras
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan, Mexico City; PECEM, Faculty of Medicine, Universidad Nacional Autónoma de México, Coyoacan, Mexico City, Mexico
| | - Germán R Magaña-Ávila
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan, Mexico City; Faculty of Medicine, Universidad Nacional Autónoma de México, Coyoacan, Mexico City
| | - Raquel Valdés
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan, Mexico City; Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Tlalpan, Mexico City
| | - Leoneli I Grajeda-Medina
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan, Mexico City
| | - Norma Vázquez
- Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Tlalpan, Mexico City
| | - Teresa Zariñán
- Red de Apoyo a la Investigación (RAI), Universidad Nacional Autónoma de México (UNAM), Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán (INCMNSZ), Mexico City, Mexico
| | - Alejandro López-Saavedra
- Unidad de Aplicaciones Avanzadas en Microscopía del Instituto Nacional de Cancerología y la Red de Apoyo a la Investigación, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Avika Sharma
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon, USA
| | - Dao-Hong Lin
- Department of Pharmacology, New York Medical College, Valhalla, New York, USA
| | - Wen-Hui Wang
- Department of Pharmacology, New York Medical College, Valhalla, New York, USA
| | - Eric Delpire
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - David H Ellison
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, Oregon, USA; Oregon Clinical & Translational Research Institute, Oregon Health & Science University, Portland, Oregon, USA; Renal Section, VA Portland Health Care System, Portland, Oregon, USA
| | - Gerardo Gamba
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan, Mexico City; PECEM, Faculty of Medicine, Universidad Nacional Autónoma de México, Coyoacan, Mexico City, Mexico; Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Tlalpan, Mexico City
| | - María Castañeda-Bueno
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan, Mexico City.
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De Carvalho H, Richard MC, Chouihed T, Goffinet N, Le Bastard Q, Freund Y, Kratz A, Dubroux M, Masson D, Figueres L, Montassier E. Electrolyte imbalance in COVID-19 patients admitted to the Emergency Department: a case-control study. Intern Emerg Med 2021; 16:1945-1950. [PMID: 33484453 PMCID: PMC7823192 DOI: 10.1007/s11739-021-02632-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 01/04/2021] [Indexed: 12/18/2022]
Abstract
In patients visiting the emergency department (ED), a potential association between electrolytes disturbance and coronavirus disease 2019 (COVID-19) has not been well studied. We aim to describe electrolyte disturbance and explore risk factors for COVID-19 infection in patients visiting the ED. We carried out a case-control study in three hospitals in France, including adult ED inpatients (≥ 18 years old). A total of 594 ED case patients in whom infection with COVID-19 was confirmed, were matched to 594 non-COVID-19 ED patients (controls) from the same period, according to sex and age. Hyponatremia was defined by a sodium of less than 135 mmol/L (reference range 135-145 mmol/L), hypokalemia by a potassium of less than 3.5 mmol/L (reference range 3.5-5.0 mmol/L), and hypochloremia by a chloride of less than 95 mmol/L (reference range 98-108 mmol/L). Among both case patients and controls, the median (IQR) age was 65 years (IQR 51-76), and 44% were women. Hyponatremia was more common among case patients than among controls, as was hypokalemia and hypochloremia. Based on the results of the multivariate logistic regression, hyponatremia, and hypokalemia were associated with COVID-19 among case patients overall, with an adjusted odds ratio of 1.89 [95% CI 1.24-2.89] for hyponatremia and 1.76 [95% CI 1.20-2.60] for hypokalemia. Hyponatremia and hypokalemia are independently associated with COVID-19 infection in adults visiting the ED, and could act as surrogate biomarkers for the emergency physician in suspected COVID-19 patients.
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Affiliation(s)
| | - Marie Caroline Richard
- Emergency Department, Hôpital Pitié-Salpêtrière, Assistance Publique, Hôpitaux de Paris (APHP), Paris, France
| | - Tahar Chouihed
- Emergency Department, University Hospital of Nancy, Centre d'Investigations Cliniques, Université de Lorraine, 1433, Inserm UMR 1116, F-CRIN INI-CRCT, Nancy, France
| | | | | | - Yonathan Freund
- Emergency Department, Hôpital Pitié-Salpêtrière, Assistance Publique, Hôpitaux de Paris (APHP), Paris, France
- Sorbonne Université, Paris, France
| | - Antoine Kratz
- Emergency Departement, University Regional Hospital, Nancy, France
| | - Marine Dubroux
- Emergency Departement, University Regional Hospital, Nancy, France
| | - Damien Masson
- Department of Biochemistry, Nantes University Hospital, 44000, Nantes, France
| | - Lucile Figueres
- Department of Nephrology, ITUNCHU Nantes, 44000, Nantes, France
| | - Emmanuel Montassier
- Emergency Department, SAMU44, CHU Nantes, 44000, Nantes, France.
- F-CRIN INI-CRCT, Nancy, France.
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Sun H, Weaver CM. Rise in Potassium Deficiency in the US Population Linked to Agriculture Practices and Dietary Potassium Deficits. J Agric Food Chem 2020; 68:11121-11127. [PMID: 32921052 DOI: 10.1021/acs.jafc.0c05139] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
This paper, for the first time, provides evidence that current practices that lead to agricultural crop removal of potassium are unsustainable and likely contributed to the decline in dietary potassium intake and rise in hypokalemia prevalence in the US population. Potassium concentrations in beef, pork, turkey, fruit, vegetables, cereal crops, and so forth decreased between 1999 and 2015 based on the examination of potassium values of food items of USDA standard reference. Ratios of potassium input to removal by crops between 1987 and 2014, potassium in topsoil, and crop-available soil potassium in US farms all declined in recent years. Reported reductions in dietary potassium intake correspond to these decreases in the food supply and to increases in hypokalemia prevalence in the US population. Results of this paper provide new understanding on links between potassium management in agricultural practices and potassium intake deficits, which is needed for combating increasing hypokalemia prevalence in the US population.
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Affiliation(s)
- Hongbing Sun
- GEMS Department, Health Studies Institute, Rider University, 2083 Lawrenceville Road, Lawrenceville, New Jersey 08648, United States
| | - Connie M Weaver
- Weaver & Associates Consulting LLC, West Lafayette, Indiana 47906, United States
- Department of Nutrition Science, Purdue University, 700 W State Street, West Lafayette, Indiana 47907, United States
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Eder M, Darmann E, Haller MC, Bojic M, Peck-Radosavljevic M, Huditz R, Bond G, Vychytil A, Reindl-Schwaighofer R, Kikić Ž. Markers of potassium homeostasis in salt losing tubulopathies- associations with hyperaldosteronism and hypomagnesemia. BMC Nephrol 2020; 21:256. [PMID: 32631286 PMCID: PMC7336449 DOI: 10.1186/s12882-020-01905-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 06/24/2020] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Renal loss of potassium (K+) and magnesium (Mg2+) in salt losing tubulopathies (SLT) leads to significantly reduced Quality of Life (QoL) and higher risks of cardiac arrhythmia. The normalization of K+ is currently the most widely accepted treatment target, however in even excellently designed RCTs the increase of K+ was only mild and rarely normalized. These findings question the role of K+ as the ideal marker of potassium homeostasis in SLT. Aim of this hypothesis-generating study was to define surrogate endpoints for future treatment trials in SLT in terms of their usefulness to determine QoL and important clinical outcomes. METHODS Within this prospective cross-sectional study including 11 patients with SLTs we assessed the biochemical, clinical and cardiological parameters and their relationship with QoL (RAND SF-36). The primary hypothesis was that QoL would be more dependent of higher aldosterone concentration, assessed by the transtubular-potassium-gradient (TTKG). Correlations were evaluated using Pearson's correlation coefficient. RESULTS Included patients were mainly female (82%, mean age 34 ± 12 years). Serum K+ and Mg2+ was 3.3 ± 0.6 mmol/l and 0.7 ± 0.1 mmol/l (mean ± SD). TTKG was 9.5/3.4-20.2 (median/range). While dimensions of mental health mostly correlated with serum Mg2+ (r = 0.68, p = 0.04) and K+ (r = 0.55, p = 0.08), better physical health was associated with lower aldosterone levels (r = -0.61, p = 0.06). TTKG was neither associated with aldosterone levels nor with QoL parameters. No relevant abnormalities were observed in neither 24 h-ECG nor echocardiography. CONCLUSIONS Hyperaldosteronism, K+ and Mg2+ were the most important parameters of QoL. TTKG was no suitable marker for hyperaldosteronism or QoL. Future confirmatory studies in SLT should assess QoL as well as aldosterone, K+ and Mg2+.
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Affiliation(s)
- Michael Eder
- Division of Nephrology and Dialysis, Department of Medicine III, Medical University Vienna, Währinger Gürtel 18-20, A-1090, Vienna, Austria
| | - Elisabeth Darmann
- Division of Nephrology and Dialysis, Department of Medicine III, Medical University Vienna, Währinger Gürtel 18-20, A-1090, Vienna, Austria
| | - Maria C Haller
- Institute of Biometrics, Center for Medical Statistics, Informatics, and Intelligent Systems, Medical University of Vienna, Vienna, Austria
| | - Marija Bojic
- Division of Nephrology and Dialysis, Department of Medicine III, Medical University Vienna, Währinger Gürtel 18-20, A-1090, Vienna, Austria
| | - Markus Peck-Radosavljevic
- Department of Internal Medicine and Gastroenterology (IMuG), Hepatology, Endocrinology, Rheumatology, Nephrology and Emergency Medicine (ZAE), Klinikum Klagenfurt am Wörthersee, Klagenfurt, Austria
| | - Rainer Huditz
- Department of Internal Medicine and Gastroenterology (IMuG), Hepatology, Endocrinology, Rheumatology, Nephrology and Emergency Medicine (ZAE), Klinikum Klagenfurt am Wörthersee, Klagenfurt, Austria
| | - Gregor Bond
- Division of Nephrology and Dialysis, Department of Medicine III, Medical University Vienna, Währinger Gürtel 18-20, A-1090, Vienna, Austria
| | - Andreas Vychytil
- Division of Nephrology and Dialysis, Department of Medicine III, Medical University Vienna, Währinger Gürtel 18-20, A-1090, Vienna, Austria
| | - Roman Reindl-Schwaighofer
- Division of Nephrology and Dialysis, Department of Medicine III, Medical University Vienna, Währinger Gürtel 18-20, A-1090, Vienna, Austria
| | - Željko Kikić
- Division of Nephrology and Dialysis, Department of Medicine III, Medical University Vienna, Währinger Gürtel 18-20, A-1090, Vienna, Austria.
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8
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Tazmini K, Frisk M, Lewalle A, Laasmaa M, Morotti S, Lipsett DB, Manfra O, Skogestad J, Aronsen JM, Sejersted OM, Sjaastad I, Edwards AG, Grandi E, Niederer SA, Øie E, Louch WE. Hypokalemia Promotes Arrhythmia by Distinct Mechanisms in Atrial and Ventricular Myocytes. Circ Res 2020; 126:889-906. [PMID: 32070187 PMCID: PMC7098435 DOI: 10.1161/circresaha.119.315641] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
RATIONALE Hypokalemia occurs in up to 20% of hospitalized patients and is associated with increased incidence of ventricular and atrial fibrillation. It is unclear whether these differing types of arrhythmia result from direct and perhaps distinct effects of hypokalemia on cardiomyocytes. OBJECTIVE To investigate proarrhythmic mechanisms of hypokalemia in ventricular and atrial myocytes. METHODS AND RESULTS Experiments were performed in isolated rat myocytes exposed to simulated hypokalemia conditions (reduction of extracellular [K+] from 5.0 to 2.7 mmol/L) and supported by mathematical modeling studies. Ventricular cells subjected to hypokalemia exhibited Ca2+ overload and increased generation of both spontaneous Ca2+ waves and delayed afterdepolarizations. However, similar Ca2+-dependent spontaneous activity during hypokalemia was only observed in a minority of atrial cells that were observed to contain t-tubules. This effect was attributed to close functional pairing of the Na+-K+ ATPase and Na+-Ca2+ exchanger proteins within these structures, as reduction in Na+ pump activity locally inhibited Ca2+ extrusion. Ventricular myocytes and tubulated atrial myocytes additionally exhibited early afterdepolarizations during hypokalemia, associated with Ca2+ overload. However, early afterdepolarizations also occurred in untubulated atrial cells, despite Ca2+ quiescence. These phase-3 early afterdepolarizations were rather linked to reactivation of nonequilibrium Na+ current, as they were rapidly blocked by tetrodotoxin. Na+ current-driven early afterdepolarizations in untubulated atrial cells were enabled by membrane hyperpolarization during hypokalemia and short action potential configurations. Brief action potentials were in turn maintained by ultra-rapid K+ current (IKur); a current which was found to be absent in tubulated atrial myocytes and ventricular myocytes. CONCLUSIONS Distinct mechanisms underlie hypokalemia-induced arrhythmia in the ventricle and atrium but also vary between atrial myocytes depending on subcellular structure and electrophysiology.
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Affiliation(s)
- Kiarash Tazmini
- From the Institute for Experimental Medical Research, Oslo University Hospital (K.T., M.F., M.L., D.B.L., O.M., J.S., J.M.A., O.M.S., I.S., W.E.L.), University of Oslo, Norway
- Department of Internal Medicine, Diakonhjemmet Hospital, Oslo, Norway (K.T., E.Ø.)
| | - Michael Frisk
- From the Institute for Experimental Medical Research, Oslo University Hospital (K.T., M.F., M.L., D.B.L., O.M., J.S., J.M.A., O.M.S., I.S., W.E.L.), University of Oslo, Norway
- KG Jebsen Center for Cardiac Research (M.F., M.L., O.M., I.S., W.E.L.), University of Oslo, Norway
| | - Alexandre Lewalle
- Division of Imaging Sciences and Biomedical Engineering, King’s College London, United Kingdom (A.L., S.A.N.)
| | - Martin Laasmaa
- From the Institute for Experimental Medical Research, Oslo University Hospital (K.T., M.F., M.L., D.B.L., O.M., J.S., J.M.A., O.M.S., I.S., W.E.L.), University of Oslo, Norway
- KG Jebsen Center for Cardiac Research (M.F., M.L., O.M., I.S., W.E.L.), University of Oslo, Norway
| | - Stefano Morotti
- Department of Pharmacology, School of Medicine, University of California Davis (S.M., A.G.E., E.G.)
| | - David B. Lipsett
- From the Institute for Experimental Medical Research, Oslo University Hospital (K.T., M.F., M.L., D.B.L., O.M., J.S., J.M.A., O.M.S., I.S., W.E.L.), University of Oslo, Norway
| | - Ornella Manfra
- From the Institute for Experimental Medical Research, Oslo University Hospital (K.T., M.F., M.L., D.B.L., O.M., J.S., J.M.A., O.M.S., I.S., W.E.L.), University of Oslo, Norway
- KG Jebsen Center for Cardiac Research (M.F., M.L., O.M., I.S., W.E.L.), University of Oslo, Norway
| | - Jonas Skogestad
- From the Institute for Experimental Medical Research, Oslo University Hospital (K.T., M.F., M.L., D.B.L., O.M., J.S., J.M.A., O.M.S., I.S., W.E.L.), University of Oslo, Norway
| | - Jan M. Aronsen
- From the Institute for Experimental Medical Research, Oslo University Hospital (K.T., M.F., M.L., D.B.L., O.M., J.S., J.M.A., O.M.S., I.S., W.E.L.), University of Oslo, Norway
- Bjørknes College, Oslo, Norway (J.M.A.)
| | - Ole M. Sejersted
- From the Institute for Experimental Medical Research, Oslo University Hospital (K.T., M.F., M.L., D.B.L., O.M., J.S., J.M.A., O.M.S., I.S., W.E.L.), University of Oslo, Norway
| | - Ivar Sjaastad
- From the Institute for Experimental Medical Research, Oslo University Hospital (K.T., M.F., M.L., D.B.L., O.M., J.S., J.M.A., O.M.S., I.S., W.E.L.), University of Oslo, Norway
- KG Jebsen Center for Cardiac Research (M.F., M.L., O.M., I.S., W.E.L.), University of Oslo, Norway
| | - Andrew G. Edwards
- Department of Pharmacology, School of Medicine, University of California Davis (S.M., A.G.E., E.G.)
| | - Eleonora Grandi
- Department of Pharmacology, School of Medicine, University of California Davis (S.M., A.G.E., E.G.)
| | - Steven A. Niederer
- Division of Imaging Sciences and Biomedical Engineering, King’s College London, United Kingdom (A.L., S.A.N.)
| | - Erik Øie
- Department of Internal Medicine, Diakonhjemmet Hospital, Oslo, Norway (K.T., E.Ø.)
| | - William E. Louch
- From the Institute for Experimental Medical Research, Oslo University Hospital (K.T., M.F., M.L., D.B.L., O.M., J.S., J.M.A., O.M.S., I.S., W.E.L.), University of Oslo, Norway
- KG Jebsen Center for Cardiac Research (M.F., M.L., O.M., I.S., W.E.L.), University of Oslo, Norway
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9
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Khadka S, K.C. I, Rayamajhi RJ, Dawadi P, Budhathoki P. Thyrotoxic Periodic Paralysis with Hypokalemia in an Adult Male from Nepal: A Case Report. JNMA J Nepal Med Assoc 2019. [PMID: 32335663 PMCID: PMC7580425 DOI: 10.31729/jnma.4763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Thyrotoxic periodic paralysis is rare complication of hyperthyroidism characterized by the sudden onset of hypokalemia and muscle paralysis. It is typically present in young Asian males. There are very few literatures regarding the occurrence of thyrotoxic hypokalemic periodic paralysis in Nepal. We reported a case of a 35-year-old male presented with the chief complaints of weakness of all four limbs of 1 day duration. He was diagnosed as a case of hyperthyroidism in the past, received treatment for 6 months and left medications on his own 6 months ago. Evaluation during admission revealed severe hypokalemia with serum potassium level 1.3mEq/l and high serum Triiodothyronine (>20.00µg/L) and low serum Thyroid Stimulating Hormone (<0.01µg/L). Potassium supplements resolved muscle weakness and the patient was restarted with anti-thyroid drugs. Hence, hypokalemic paralysis is a reversible cause of paralysis and high index of suspicion as well as timely interventions are required to prevent potential harm.
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Affiliation(s)
- Sabina Khadka
- Nepalese Army Institute of Health Sciences, Sanobharyang, Kathmandu, Nepal
| | - Indu K.C.
- Department of Medicine, Shree Birendra Hospital, Chhauni, Kathmandu, Nepal
| | | | - Pravakar Dawadi
- Nepalese Army Institute of Health Sciences, Sanobharyang, Kathmandu, Nepal
- Correspondence: Mr. Pravakar Dawadi, Nepalese Army Institute of Health Sciences, Sanobharyang, Kathmandu, Nepal. , Phone: +977-9841215580
| | - Pravash Budhathoki
- Nepalese Army Institute of Health Sciences, Sanobharyang, Kathmandu, Nepal
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10
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Matsuura Y, Nomura N, Shoda W, Mori T, Isobe K, Susa K, Ando F, Sohara E, Rai T, Uchida S. Tacrolimus ameliorates the phenotypes of type 4 Bartter syndrome model mice through activation of sodium-potassium-2 chloride cotransporter and sodium-chloride cotransporter. Biochem Biophys Res Commun 2019; 517:364-368. [PMID: 31362893 DOI: 10.1016/j.bbrc.2019.07.086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2019] [Accepted: 07/22/2019] [Indexed: 11/18/2022]
Abstract
Type 4 Bartter syndrome (BS) is caused by genetic mutations in barttin, which is coded for by BSND. Barttin serves as the β-subunit of the ClC-K chloride (Cl-) channel, which is widely expressed in distal nephrons. Type 4 BS is characterized by severely impaired reabsorption of salt, which may cause polyuria, hypokalemia, and metabolic alkalosis. Calcineurin inhibitors reportedly induce renal salt retention and hyperkalemia by enhancing the phosphorylation of the sodium (Na+)-potassium (K+)-2Cl- cotransporter (NKCC2) and Na+-Cl- cotransporter (NCC). In addition, we have previously reported that tacrolimus, a calcineurin inhibitor, increases the levels of phosphorylated NCC. In this study, we administered tacrolimus to barttin hypomorphic (Bsndneo/neo) mice, a murine model of type 4 BS that exhibits polyuria, hypokalemia, and metabolic alkalosis. Administration of tacrolimus increased the serum K+ level and suppressed urinary K+ excretion. Furthermore, after treatment with tacrolimus, Bsndneo/neo mice increased levels of phosphorylated NCC and NKCC2. We conclude that tacrolimus partially improves clinical phenotypes of Bsndneo/neo mice, and that calcineurin inhibitors might be effective for treating type 4 BS.
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Affiliation(s)
- Yoshiaki Matsuura
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, 113-8519, Japan
| | - Naohiro Nomura
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, 113-8519, Japan.
| | - Wakana Shoda
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, 113-8519, Japan
| | - Takayasu Mori
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, 113-8519, Japan
| | - Kiyoshi Isobe
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, 113-8519, Japan
| | - Koichiro Susa
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, 113-8519, Japan
| | - Fumiaki Ando
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, 113-8519, Japan
| | - Eisei Sohara
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, 113-8519, Japan
| | - Tatemitsu Rai
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, 113-8519, Japan
| | - Shinichi Uchida
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, 113-8519, Japan
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11
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Wu P, Gao ZX, Zhang DD, Su XT, Wang WH, Lin DH. Deletion of Kir5.1 Impairs Renal Ability to Excrete Potassium during Increased Dietary Potassium Intake. J Am Soc Nephrol 2019; 30:1425-1438. [PMID: 31239388 PMCID: PMC6683724 DOI: 10.1681/asn.2019010025] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 04/24/2019] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND The basolateral potassium channel in the distal convoluted tubule (DCT), comprising the inwardly rectifying potassium channel Kir4.1/Kir5.1 heterotetramer, plays a key role in mediating the effect of dietary potassium intake on the thiazide-sensitive NaCl cotransporter (NCC). The role of Kir5.1 (encoded by Kcnj16) in mediating effects of dietary potassium intake on the NCC and renal potassium excretion is unknown. METHODS We used electrophysiology, renal clearance, and immunoblotting to study Kir4.1 in the DCT and NCC in Kir5.1 knockout (Kcnj16-/- ) and wild-type (Kcnj16+/+ ) mice fed with normal, high, or low potassium diets. RESULTS We detected a 40-pS and 20-pS potassium channel in the basolateral membrane of the DCT in wild-type and knockout mice, respectively. Compared with wild-type, Kcnj16-/- mice fed a normal potassium diet had higher basolateral potassium conductance, a more negative DCT membrane potential, higher expression of phosphorylated NCC (pNCC) and total NCC (tNCC), and augmented thiazide-induced natriuresis. Neither high- nor low-potassium diets affected the basolateral DCT's potassium conductance and membrane potential in Kcnj16-/- mice. Although high potassium reduced and low potassium increased the expression of pNCC and tNCC in wild-type mice, these effects were absent in Kcnj16-/- mice. High potassium intake inhibited and low intake augmented thiazide-induced natriuresis in wild-type but not in Kcnj16-/- mice. Compared with wild-type, Kcnj16-/- mice with normal potassium intake had slightly lower plasma potassium but were more hyperkalemic with prolonged high potassium intake and more hypokalemic during potassium restriction. CONCLUSIONS Kir5.1 is essential for dietary potassium's effect on NCC and for maintaining potassium homeostasis.
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Affiliation(s)
- Peng Wu
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Zhong-Xiuzi Gao
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Dan-Dan Zhang
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Xiao-Tong Su
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Wen-Hui Wang
- Department of Pharmacology, New York Medical College, Valhalla, New York
| | - Dao-Hong Lin
- Department of Pharmacology, New York Medical College, Valhalla, New York
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12
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Osis G, Webster KL, Harris AN, Lee HW, Chen C, Fang L, Romero MF, Khattri RB, Merritt ME, Verlander JW, Weiner ID. Regulation of renal NaDC1 expression and citrate excretion by NBCe1-A. Am J Physiol Renal Physiol 2019; 317:F489-F501. [PMID: 31188034 PMCID: PMC6732450 DOI: 10.1152/ajprenal.00015.2019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 05/20/2019] [Accepted: 06/07/2019] [Indexed: 11/22/2022] Open
Abstract
Citrate is critical for acid-base homeostasis and to prevent calcium nephrolithiasis. Both metabolic acidosis and hypokalemia decrease citrate excretion and increase expression of Na+-dicarboxylate cotransporter 1 (NaDC1; SLC13A2), the primary protein involved in citrate reabsorption. However, the mechanisms transducing extracellular signals and mediating these responses are incompletely understood. The purpose of the present study was to determine the role of the Na+-coupled electrogenic bicarbonate cotransporter (NBCe1) A variant (NBCe1-A) in citrate metabolism under basal conditions and in response to acid loading and hypokalemia. NBCe1-A deletion increased citrate excretion and decreased NaDC1 expression in the proximal convoluted tubules (PCT) and proximal straight tubules (PST) in the medullary ray (PST-MR) but not in the PST in the outer medulla (PST-OM). Acid loading wild-type (WT) mice decreased citrate excretion. NaDC1 expression increased only in the PCT and PST-MR and not in the PST-MR. In NBCe1-A knockout (KO) mice, the acid loading change in citrate excretion was unaffected, changes in PCT NaDC1 expression were blocked, and there was an adaptive increase in PST-MR. Hypokalemia in WT mice decreased citrate excretion; NaDC1 expression increased only in the PCT and PST-MR. NBCe1-A KO blocked both the citrate and NaDC1 changes. We conclude that 1) adaptive changes in NaDC1 expression in response to metabolic acidosis and hypokalemia occur specifically in the PCT and PST-MR, i.e., in cortical proximal tubule segments; 2) NBCe1-A is necessary for normal basal, metabolic acidosis and hypokalemia-stimulated citrate metabolism and does so by regulating NaDC1 expression in cortical proximal tubule segments; and 3) adaptive increases in PST-OM NaDC1 expression occur in NBCe1-A KO mice in response to acid loading that do not occur in WT mice.
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Affiliation(s)
- Gunars Osis
- Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine, Gainesville, Florida
| | - Kierstin L Webster
- Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine, Gainesville, Florida
| | - Autumn N Harris
- Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine, Gainesville, Florida
- Department of Small Animal Clinical Sciences, University of Florida College of Veterinary Medicine, Gainesville, Florida
| | - Hyun-Wook Lee
- Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine, Gainesville, Florida
| | - Chao Chen
- Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine, Gainesville, Florida
| | - Lijuan Fang
- Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine, Gainesville, Florida
| | - Michael F Romero
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Ram B Khattri
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, Florida
| | - Matthew E Merritt
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, Florida
| | - Jill W Verlander
- Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine, Gainesville, Florida
| | - I David Weiner
- Division of Nephrology, Hypertension and Transplantation, University of Florida College of Medicine, Gainesville, Florida
- Nephrology and Hypertension Section, North Florida/South Georgia Veterans Health System, Gainesville, Florida
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13
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Puissant MM, Muere C, Levchenko V, Manis AD, Martino P, Forster HV, Palygin O, Staruschenko A, Hodges MR. Genetic mutation of Kcnj16 identifies Kir5.1-containing channels as key regulators of acute and chronic pH homeostasis. FASEB J 2019; 33:5067-5075. [PMID: 30605394 PMCID: PMC6436665 DOI: 10.1096/fj.201802257r] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 12/10/2018] [Indexed: 12/22/2022]
Abstract
Acute and chronic homeostatic pH regulation is critical for the maintenance of optimal cellular function. Renal mechanisms dominate global pH regulation over longer time frames, and rapid adjustments in ventilation compensate for acute pH and CO2 changes. Ventilatory CO2 and pH chemoreflexes are primarily determined by brain chemoreceptors with intrinsic pH sensitivity likely driven by K+ channels. Here, we studied acute and chronic pH regulation in Kcnj16 mutant Dahl salt-sensitive (SS Kcnj16-/-) rats; Kcnj16 encodes the pH-sensitive inwardly rectifying K+ 5.1 (Kir5.1) channel. SS Kcnj16-/- rats hyperventilated at rest, likely compensating for a chronic metabolic acidosis. Despite their resting hyperventilation, SS Kcnj16-/- rats showed up to 45% reduction in the ventilatory response to graded hypercapnic acidosis vs. controls. SS Kcnj16-/- rats chronically treated with bicarbonate or the carbonic anhydrase inhibitor hydrochlorothiazide had partial restoration of arterial pH, but there was a further reduction in the ventilatory response to hypercapnic acidosis. SS Kcnj16-/- rats also had a nearly absent hypoxic ventilatory response, suggesting major contributions of Kir5.1 to O2- and CO2-dependent chemoreflexes. Although previous studies demonstrated beneficial effects of a high-K+ diet (HKD) on cardiorenal phenotypes in SS Kcnj16-/- rats, HKD failed to restore the observed ventilatory phenotypes. We conclude that Kir5.1 is a key regulator of renal H+ handling and essential for acute and chronic regulation of arterial pH as determinants of the ventilatory CO2 chemoreflex.-Puissant, M. M., Muere, C., Levchenko, V., Manis, A. D., Martino, P., Forster, H. V., Palygin, O., Staruschenko, A., Hodges, M. R. Genetic mutation of Kcnj16 identifies Kir5.1-containing channels as key regulators of acute and chronic pH homeostasis.
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Affiliation(s)
| | - Clarissa Muere
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Vladislav Levchenko
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Anna D. Manis
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Paul Martino
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
- Department of Biology, Carthage College, Kenosha, Wisconsin, USA; and
| | - Hubert V. Forster
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Oleg Palygin
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
- Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | | | - Matthew R. Hodges
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
- Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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14
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Ahmed KS, Bogdanet D, Abadi S, Dineen R, Boran G, Woods CP, Behan LA, Sherlock M, Gibney J. Rates of abnormal aldosterone/renin ratio in African-origin compared to European-origin patients: A retrospective study. Clin Endocrinol (Oxf) 2019; 90:528-533. [PMID: 30575078 DOI: 10.1111/cen.13920] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 12/11/2018] [Accepted: 12/18/2018] [Indexed: 12/01/2022]
Abstract
INTRODUCTION The aldosterone/renin ratio is the initial screening test for primary hyperaldosteronism (PHA), but little data exists regarding ethnic variations in this. METHODS Following clinical observation of a high prevalence of abnormal aldosterone/renin ratio (ARR) in patients of African-origin, we retrospectively reviewed all ARR measurements in a single centre over 10 years. Rates of hypokalaemia, intraventricular septal thickness (IVS, by echocardiography) and adrenal imaging were recorded when available. RESULTS Aldosterone/renin ratio was available in 1473 patients, and abnormal in 374 (25.4%). Abnormal ARR was observed in 305/1349 (22.6%) of European-origin and 69/124 (55.6%) of African-origin patients (P < 0.001). Among those with abnormal ARR, hypokalaemia (<3.5 mmol/L) was documented on at least one occasion in 171/305 (56.1%) European-origin and 43/69 (62.3%) African-origin patients (P = 0.35). Median (range) IVS was 1.57 (0.78-2.80) cm in African-origin and 1.20 (0.69-2.18) cm in European-origin patients (P < 0.002); IVS did not correlate with aldosterone or ARR however. Adrenal adenoma was identified in 41/170 (24.1%) of European-origin and 4/29 (13.7%) African-origin patients (P = 0.15), while hyperplasia was identified in 35/170 (20.5%) of European and 8/29 (27.5%) African patients (P = 0.39). CONCLUSION In summary, ARR was abnormal in 55.6% of African-origin patients screened at an Irish hospital. Rates of hypokalaemia were similar between European-origin and African-origin patients. These findings have implications for the use of current screening guidelines for ARR in African-origin patients and also for the mechanistic role of aldosterone in hypertensive complications in African-origin patients.
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Affiliation(s)
- Khalid S Ahmed
- Department of Endocrinology, The Adelaide and Meath Hospital, Incorporating the National Children's Hospital, Tallaght, Dublin, Ireland
| | - Delia Bogdanet
- Department of Endocrinology, The Adelaide and Meath Hospital, Incorporating the National Children's Hospital, Tallaght, Dublin, Ireland
| | - Sorresa Abadi
- Department of Cardiology, The Adelaide and Meath Hospital, Incorporating the National Children's Hospital, Tallaght, Dublin, Ireland
| | - RoseMary Dineen
- Department of Endocrinology, The Adelaide and Meath Hospital, Incorporating the National Children's Hospital, Tallaght, Dublin, Ireland
| | - Gerald Boran
- Department of Chemical Pathology, The Adelaide and Meath Hospital, Incorporating the National Children's Hospital, Tallaght, Dublin, Ireland
| | - Conor P Woods
- Department of Endocrinology, The Adelaide and Meath Hospital, Incorporating the National Children's Hospital, Tallaght, Dublin, Ireland
| | - Lucy Ann Behan
- Department of Endocrinology, The Adelaide and Meath Hospital, Incorporating the National Children's Hospital, Tallaght, Dublin, Ireland
| | - Mark Sherlock
- Department of Endocrinology, The Adelaide and Meath Hospital, Incorporating the National Children's Hospital, Tallaght, Dublin, Ireland
| | - James Gibney
- Department of Endocrinology, The Adelaide and Meath Hospital, Incorporating the National Children's Hospital, Tallaght, Dublin, Ireland
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15
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Kaplan M, Ateş I, Gökcan H, Kayhan MA, Kaçar S, Akpınar MY, Gökbulut V, Kayaçetin E. Prognostic Utility of Hypokalemia in Cirrhotic Patients. Acta Gastroenterol Belg 2018; 81:398-403. [PMID: 30350528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
BACKGROUND AND AIM We researched the relationships between serum potassium level and prognostic scores and complications of cirrhosis, and mortality. METHODS This study was performed retrospectively in Turkish High Specialty Training and Research Hospital between 2009 and 2015. Patients who had missing patient files and electrolyte disorder for another reason, showed complications at the time of application and were using diuretics were excluded from the study. RESULTS 218 patients were included in the study. During the follow-up period, 23.4% (n: 51) of the entire population passed away. Compared to the patients who survived, the patients who passed away had higher HCC and HES development rate, mean Child-Pugh and MELD score and lower mean blood potassium level. The stepwise multivariable Cox regression model which included significant independent predictors showed that ChildPugh score (HR: 1.29; p <0.001), MELD score (HR:1.13; p= 0.006), and potassium level (HR: 0.18; p< 0.001) were independent predictors of mortality. The cut off value for potassium level in predicting mortality was found to be ≤ 3.4 mmol/L with 80.4% sensitivity and 100% specificity. Compared to the patients with a potassium level > 3.4 mmol/L, the patients with a potassium level ≤ 3.4 mmol/L had higher mortality rate, HCC and HES development rate, mean Child-Pugh and mean MELD scores. CONCLUSION Hypokalemia is an important prognostic factor in cirrhotic patients.
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Affiliation(s)
- M Kaplan
- Turkey Yuksek Ihtisas Training and Research Hospital, Department of Gastroenterology, Ankara, Turkey
| | - I Ateş
- Ankara Numune Training and Research Hospital, Department of Internal Medicine, Ankara, Turkey
| | - H Gökcan
- Turkey Yuksek Ihtisas Training and Research Hospital, Department of Gastroenterology, Ankara, Turkey
| | - M A Kayhan
- Turkey Yuksek Ihtisas Training and Research Hospital, Department of Gastroenterology, Ankara, Turkey
| | - S Kaçar
- Turkey Yuksek Ihtisas Training and Research Hospital, Department of Gastroenterology, Ankara, Turkey
| | - M Y Akpınar
- Turkey Yuksek Ihtisas Training and Research Hospital, Department of Gastroenterology, Ankara, Turkey
| | - V Gökbulut
- Turkey Yuksek Ihtisas Training and Research Hospital, Department of Gastroenterology, Ankara, Turkey
| | - E Kayaçetin
- Turkey Yuksek Ihtisas Training and Research Hospital, Department of Gastroenterology, Ankara, Turkey
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16
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Turakhia MP, Blankestijn PJ, Carrero JJ, Clase CM, Deo R, Herzog CA, Kasner SE, Passman RS, Pecoits-Filho R, Reinecke H, Shroff GR, Zareba W, Cheung M, Wheeler DC, Winkelmayer WC, Wanner C. Chronic kidney disease and arrhythmias: conclusions from a Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference. Eur Heart J 2018; 39:2314-2325. [PMID: 29522134 PMCID: PMC6012907 DOI: 10.1093/eurheartj/ehy060] [Citation(s) in RCA: 151] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 12/18/2017] [Accepted: 01/27/2018] [Indexed: 12/15/2022] Open
MESH Headings
- Arrhythmias, Cardiac/epidemiology
- Arrhythmias, Cardiac/therapy
- Atrial Fibrillation/complications
- Atrial Fibrillation/drug therapy
- Atrial Fibrillation/epidemiology
- Death, Sudden, Cardiac/prevention & control
- Defibrillators, Implantable
- Humans
- Hyperkalemia/epidemiology
- Hyperkalemia/metabolism
- Hypokalemia/epidemiology
- Hypokalemia/metabolism
- Inflammation
- Kidney Failure, Chronic/epidemiology
- Kidney Failure, Chronic/metabolism
- Kidney Failure, Chronic/therapy
- Oxidative Stress
- Potassium/metabolism
- Renal Dialysis
- Renal Insufficiency, Chronic/epidemiology
- Renal Insufficiency, Chronic/metabolism
- Renal Insufficiency, Chronic/therapy
- Risk Factors
- Stroke/etiology
- Stroke/prevention & control
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Affiliation(s)
- Mintu P Turakhia
- Stanford University School of Medicine, Veterans Affairs Palo Alto Health Care System, Miranda Ave, Palo Alto, CA, USA
| | - Peter J Blankestijn
- Department of Nephrology, room F03.220, University Medical Center, Utrecht, The Netherlands
| | - Juan-Jesus Carrero
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Nobels väg 12A, Stockholm, Sweden
| | - Catherine M Clase
- Department of Medicine and Department of Health Research Methods, Evidence, and Impact, McMaster University, St. Joseph’s Healthcare, Marian Wing, 3rd Floor, M333, 50 Charlton Ave. E, Hamilton, Ontario, Canada
| | - Rajat Deo
- Section of Electrophysiology, Division of Cardiovascular Medicine, Perelman School of Medicine at the University of Pennsylvania, 3400 Spruce Street, 9 Founders Cardiology, Philadelphia, PA, USA
| | - Charles A Herzog
- Division of Cardiology, Department of Medicine, Hennepin County Medical Center and University of Minnesota, Minneapolis, Minnesota and Chronic Disease Research Group, Minneapolis Medical Research Foundation, 914 S. 8th Street, S4.100, Minneapolis, MN, USA
| | - Scott E Kasner
- Department of Neurology, 3W Gates Bldg. Hospital of the University of Pennsylvania, 3400 Spruce St., Philadelphia, PA, USA
| | - Rod S Passman
- Northwestern University Feinberg School of Medicine and the Bluhm Cardiovascular Institute, 201 E. Huron St. Chicago, IL, USA
| | - Roberto Pecoits-Filho
- School of Medicine, Pontificia Universidade Catolica do Paraná, Rua Imaculada Conceição Curitiba PR, Brazil
| | - Holger Reinecke
- Department für Kardiologie und Angiologie Universitätsklinikum Münster, Albert-Schweitzer-Campus 1, Gebäude A1, Muenster, Germany
| | - Gautam R Shroff
- Division of Cardiology, Hennepin County Medical Center, 701 Park Avenue, Minneapolis, MN, USA
| | - Wojciech Zareba
- Heart Research Follow-up Program, Cardiology Division, University of Rochester Medical Center, Saunders Research Building, 265 Crittenden Blvd. CU, Rochester, NY, USA
| | | | - David C Wheeler
- Centre for Nephrology, University College London, Rowland Hill Street, London, UK
| | - Wolfgang C Winkelmayer
- Selzman Institute for Kidney Health, Section of Nephrology, Department of Medicine, Baylor College of Medicine, One Baylor Plaza, ABBR R705, MS: 395, Houston, TX, USA
| | - Christoph Wanner
- Division of Nephrology, Department of Medicine, University Hospital of Würzburg, Oberduerrbacherstr. 6 Würzburg, Germany
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17
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Wang MX, Cuevas CA, Su XT, Wu P, Gao ZX, Lin DH, McCormick JA, Yang CL, Wang WH, Ellison DH. Potassium intake modulates the thiazide-sensitive sodium-chloride cotransporter (NCC) activity via the Kir4.1 potassium channel. Kidney Int 2018; 93:893-902. [PMID: 29310825 PMCID: PMC6481177 DOI: 10.1016/j.kint.2017.10.023] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 10/04/2017] [Accepted: 10/12/2017] [Indexed: 12/14/2022]
Abstract
Kir4.1 in the distal convoluted tubule plays a key role in sensing plasma potassium and in modulating the thiazide-sensitive sodium-chloride cotransporter (NCC). Here we tested whether dietary potassium intake modulates Kir4.1 and whether this is essential for mediating the effect of potassium diet on NCC. High potassium intake inhibited the basolateral 40 pS potassium channel (a Kir4.1/5.1 heterotetramer) in the distal convoluted tubule, decreased basolateral potassium conductance, and depolarized the distal convoluted tubule membrane in Kcnj10flox/flox mice, herein referred to as control mice. In contrast, low potassium intake activated Kir4.1, increased potassium currents, and hyperpolarized the distal convoluted tubule membrane. These effects of dietary potassium intake on the basolateral potassium conductance and membrane potential in the distal convoluted tubule were completely absent in inducible kidney-specific Kir4.1 knockout mice. Furthermore, high potassium intake decreased, whereas low potassium intake increased the abundance of NCC expression only in the control but not in kidney-specific Kir4.1 knockout mice. Renal clearance studies demonstrated that low potassium augmented, while high potassium diminished, hydrochlorothiazide-induced natriuresis in control mice. Disruption of Kir4.1 significantly increased basal urinary sodium excretion but it abolished the natriuretic effect of hydrochlorothiazide. Finally, hypokalemia and metabolic alkalosis in kidney-specific Kir4.1 knockout mice were exacerbated by potassium restriction and only partially corrected by a high-potassium diet. Thus, Kir4.1 plays an essential role in mediating the effect of dietary potassium intake on NCC activity and potassium homeostasis.
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MESH Headings
- Alkalosis/genetics
- Alkalosis/metabolism
- Alkalosis/physiopathology
- Animals
- Disease Models, Animal
- Female
- Homeostasis
- Hydrochlorothiazide/pharmacology
- Hypokalemia/genetics
- Hypokalemia/metabolism
- Hypokalemia/physiopathology
- Kidney Tubules, Distal/drug effects
- Kidney Tubules, Distal/metabolism
- Kidney Tubules, Distal/physiopathology
- Male
- Membrane Potentials
- Mice, Knockout
- Natriuresis
- Potassium Channels, Inwardly Rectifying/deficiency
- Potassium Channels, Inwardly Rectifying/genetics
- Potassium Channels, Inwardly Rectifying/metabolism
- Potassium, Dietary/metabolism
- Renal Elimination
- Sodium/urine
- Sodium Chloride Symporter Inhibitors/pharmacology
- Solute Carrier Family 12, Member 3/genetics
- Solute Carrier Family 12, Member 3/metabolism
- Kir5.1 Channel
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Affiliation(s)
- Ming-Xiao Wang
- Department of Physiology, Zunyi Medical College, Zunyi, China; Department of Pharmacology, New York Medical College, Valhalla, New York, USA
| | - Catherina A Cuevas
- Department of Medicine, Oregon Health & Science University, Portland, Oregon, USA
| | - Xiao-Tong Su
- Department of Pharmacology, New York Medical College, Valhalla, New York, USA
| | - Peng Wu
- Department of Pharmacology, New York Medical College, Valhalla, New York, USA
| | - Zhong-Xiuzi Gao
- Department of Pharmacology, New York Medical College, Valhalla, New York, USA
| | - Dao-Hong Lin
- Department of Pharmacology, New York Medical College, Valhalla, New York, USA
| | - James A McCormick
- Department of Medicine, Oregon Health & Science University, Portland, Oregon, USA
| | - Chao-Ling Yang
- Department of Pharmacology, New York Medical College, Valhalla, New York, USA
| | - Wen-Hui Wang
- Department of Pharmacology, New York Medical College, Valhalla, New York, USA.
| | - David H Ellison
- Department of Medicine, Oregon Health & Science University, Portland, Oregon, USA.
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18
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Abstract
Primary aldosteronism (PA), the most common form of secondary hypertension, is caused in the majority of cases by unilateral aldosterone-producing adenoma (APA) or bilateral adrenal hyperplasia. Over the past few years, somatic mutations in KCNJ5, CACNA1D, ATP1A1 and ATP2B3 have been proven to be associated with APA development, representing more than 50% of sporadic APA. The identification of these mutations has allowed the development of a model for APA involving modification on the intracellular ionic equilibrium and regulation of cell membrane potential, leading to autonomous aldosterone overproduction. Furthermore, somatic CTNNB1 mutations have also been identified in APA, but the link between these mutations and APA development remains unknown. The sequence of events responsible for APA formation is not completely understood, in particular, whether a single hit or a double hit is responsible for both aldosterone overproduction and cell proliferation. Germline mutations identified in patients with early-onset PA have expanded the classification of familial forms (FH) of PA. The description of germline KCNJ5 and CACNA1H mutations has identified FH-III and FH-IV based on genetic findings; germline CACNA1D mutations have been identified in patients with very early-onset PA and severe neurological abnormalities. This review summarizes current knowledge on the genetic basis of PA, the association of driver gene mutations and clinical findings and in the contribution to patient care, plus the current understanding on the mechanisms of APA development.
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Affiliation(s)
- Fabio Luiz Fernandes-Rosa
- INSERMUMRS_970, Paris Cardiovascular Research Center, Paris, France
- University Paris DescartesSorbonne Paris Cité, Paris, France
- Assistance Publique-Hôpitaux de ParisHôpital Européen Georges Pompidou, Service de Génétique, Paris, France
| | - Sheerazed Boulkroun
- INSERMUMRS_970, Paris Cardiovascular Research Center, Paris, France
- University Paris DescartesSorbonne Paris Cité, Paris, France
| | - Maria-Christina Zennaro
- INSERMUMRS_970, Paris Cardiovascular Research Center, Paris, France
- University Paris DescartesSorbonne Paris Cité, Paris, France
- Assistance Publique-Hôpitaux de ParisHôpital Européen Georges Pompidou, Service de Génétique, Paris, France
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19
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Abstract
We report on two teenage girls presenting following significant paracetamol overdoses (>28 g paracetamol). Both presented within 4 h of the overdose and both were treated with N-acetylcysteine, in accordance with the National Poisons Information Service protocol. Within 8 h of presentation both had developed significant hypokalaemia with serum potassium concentrations <3.0 mmol/L and were treated with intravenous potassium chloride. Potassium concentrations returned to within reference limits (>3.5 mmol/L) after commencing potassium chloride supplementation. An audit of potassium concentrations in 254 patients presenting with significant paracetamol overdose (paracetamol >0.5 mmol/L) admitted through four A&E departments in the West of Scotland showed a significant decline in mean serum potassium from 3.9 mmol/L on admission to 3.6 mmol/L ( P = <0.001) over the next 36 h. The mechanism for this hypokalaemia in these two individuals is unclear, however regular monitoring of potassium is advocated in such patients during their initial treatment.
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Affiliation(s)
- Ian M Godber
- Biochemistry Department, Wishaw General Hospital, Wishaw, Lanarkshire, UK.
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20
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Khositseth S, Uawithya P, Somparn P, Charngkaew K, Thippamom N, Hoffert JD, Saeed F, Michael Payne D, Chen SH, Fenton RA, Pisitkun T. Autophagic degradation of aquaporin-2 is an early event in hypokalemia-induced nephrogenic diabetes insipidus. Sci Rep 2015; 5:18311. [PMID: 26674602 PMCID: PMC4682130 DOI: 10.1038/srep18311] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 11/16/2015] [Indexed: 12/19/2022] Open
Abstract
Hypokalemia (low serum potassium level) is a common electrolyte imbalance that can cause a defect in urinary concentrating ability, i.e., nephrogenic diabetes insipidus (NDI), but the molecular mechanism is unknown. We employed proteomic analysis of inner medullary collecting ducts (IMCD) from rats fed with a potassium-free diet for 1 day. IMCD protein quantification was performed by mass spectrometry using a label-free methodology. A total of 131 proteins, including the water channel AQP2, exhibited significant changes in abundance, most of which were decreased. Bioinformatic analysis revealed that many of the down-regulated proteins were associated with the biological processes of generation of precursor metabolites and energy, actin cytoskeleton organization, and cell-cell adhesion. Targeted LC-MS/MS and immunoblotting studies further confirmed the down regulation of 18 selected proteins. Electron microscopy showed autophagosomes/autophagolysosomes in the IMCD cells of rats deprived of potassium for only 1 day. An increased number of autophagosomes was also confirmed by immunofluorescence, demonstrating co-localization of LC3 and Lamp1 with AQP2 and several other down-regulated proteins in IMCD cells. AQP2 was also detected in autophagosomes in IMCD cells of potassium-deprived rats by immunogold electron microscopy. Thus, enhanced autophagic degradation of proteins, most notably including AQP2, is an early event in hypokalemia-induced NDI.
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Affiliation(s)
- Sookkasem Khositseth
- Department of Pediatrics, Faculty of Medicine, Thammasat University Klong Luang, Pathumthani, 12120, Thailand
| | - Panapat Uawithya
- Department of Physiology, Faculty of Medicine Siriraj Hospital, Mahidol University Bangkok, 10700, Thailand
| | - Poorichaya Somparn
- Systems Biology Center, Research Affairs, Faculty of Medicine, Chulalongkorn University 1873 Rama 4 Road, Pathumwan, Bangkok, 10330, Thailand
| | - Komgrid Charngkaew
- Department of Pathology, Faculty of Medicine Siriraj Hospital, Mahidol University Bangkok, 10700, Thailand
| | - Nattakan Thippamom
- Department of Pediatrics, Faculty of Medicine, Thammasat University Klong Luang, Pathumthani, 12120, Thailand
| | - Jason D. Hoffert
- National Institute of Diabetes and Digestive and Kidney, Bethesda MD 20892, United States
| | - Fahad Saeed
- Department of Electrical & Computer Engineering and Department of Computer Science, Western Michigan University Kalamazoo, 49008, United States
| | - D. Michael Payne
- Systems Biology Center, Research Affairs, Faculty of Medicine, Chulalongkorn University 1873 Rama 4 Road, Pathumwan, Bangkok, 10330, Thailand
| | - Shu-Hui Chen
- Department of Chemistry, National Cheng Kung University, Tainan City, 701, Taiwan
| | - Robert A. Fenton
- Department of Biomedicine and Center for Interactions of Proteins in Epithelial Transport, Aarhus University, Aarhus, 8000, Denmark
| | - Trairak Pisitkun
- Systems Biology Center, Research Affairs, Faculty of Medicine, Chulalongkorn University 1873 Rama 4 Road, Pathumwan, Bangkok, 10330, Thailand
- Department of Biomedicine and Center for Interactions of Proteins in Epithelial Transport, Aarhus University, Aarhus, 8000, Denmark
- Epithelial Systems Biology Laboratory, National Heart, Lung, and Blood Institute, Bethesda MD 20892, United States
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21
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Lodin K, Palmér M. [Investigation of hypokalemia]. Lakartidningen 2015; 112:DRFX. [PMID: 26671430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Most causes of hypokalemia could be studied relatively easily by thorough medical history and basal sampling. Moreover, difficult cases of hypokalemia should be studied systematically to identify the underlying cause so that successful long-term treatments can be applied.
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Affiliation(s)
- Karin Lodin
- Älvsjö Vårdcentral - Älvsjö, Sweden Älvsjö Vårdcentral - Älvsjö, Sweden
| | - Mats Palmér
- Karolinska Universitetssjukhuset - Kliniken för endokrinologi, metabolism och diabetes Huddinge, Sweden - , Sweden
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22
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23
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Junco E, Perez R, Jofre R, Alonso S, Rengel M, Valderrabano F, Vinay P. Renal ammoniagenesis in acute hypokalemia in vivo in the dog. Contrib Nephrol 2015; 63:125-31. [PMID: 3191703 DOI: 10.1159/000415709] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- E Junco
- Nephrology Service, Hospital General Gregorio Marañon, Madrid, Spain
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24
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van den Meiracker AH, van der Linde AAA, Claahsen van der Grinten HL, Danser AHJJ, Deinum J. [Primary aldosteronism: new insights into familial forms]. Ned Tijdschr Geneeskd 2015; 159:A8932. [PMID: 26420144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Primary aldosteronism (PA) is characterized by autonomic aldosterone production, usually leading to severe hypertension and hypokalaemia. PA is a heterogeneous condition caused by sporadic adrenal adenoma, bilateral adrenal hyperplasia or rare familial forms. Familial aldosteronism type 1 is caused by a hybrid gene that codes for an ACTH-sensitive form of aldosterone synthase. Familial aldosteronism type 3 was recently recognized as a new form of PA caused by mutation in KCNJ5. The clinical manifestations vary from life-threatening PA and pronounced adrenal hyperplasia to milder forms. In addition to germline mutations in KCNJ5, somatic KCNJ5 mutations are present in about 40% of aldosterone-producing adrenal adenomas. Mutations in three other genes are also regularly observed. All these mutations cause increased aldosterone synthase activity, eventually leading to PA. In patients under 20 with PA, familial forms must be excluded before proceeding to adrenalectomy.
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25
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Adeva-Andany MM, Fernández-Fernández C, Mouriño-Bayolo D, Castro-Quintela E, Domínguez-Montero A. Sodium bicarbonate therapy in patients with metabolic acidosis. ScientificWorldJournal 2014; 2014:627673. [PMID: 25405229 PMCID: PMC4227445 DOI: 10.1155/2014/627673] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 09/05/2014] [Accepted: 09/19/2014] [Indexed: 01/18/2023] Open
Abstract
Metabolic acidosis occurs when a relative accumulation of plasma anions in excess of cations reduces plasma pH. Replacement of sodium bicarbonate to patients with sodium bicarbonate loss due to diarrhea or renal proximal tubular acidosis is useful, but there is no definite evidence that sodium bicarbonate administration to patients with acute metabolic acidosis, including diabetic ketoacidosis, lactic acidosis, septic shock, intraoperative metabolic acidosis, or cardiac arrest, is beneficial regarding clinical outcomes or mortality rate. Patients with advanced chronic kidney disease usually show metabolic acidosis due to increased unmeasured anions and hyperchloremia. It has been suggested that metabolic acidosis might have a negative impact on progression of kidney dysfunction and that sodium bicarbonate administration might attenuate this effect, but further evaluation is required to validate such a renoprotective strategy. Sodium bicarbonate is the predominant buffer used in dialysis fluids and patients on maintenance dialysis are subjected to a load of sodium bicarbonate during the sessions, suffering a transient metabolic alkalosis of variable severity. Side effects associated with sodium bicarbonate therapy include hypercapnia, hypokalemia, ionized hypocalcemia, and QTc interval prolongation. The potential impact of regular sodium bicarbonate therapy on worsening vascular calcifications in patients with chronic kidney disease has been insufficiently investigated.
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Affiliation(s)
- María M. Adeva-Andany
- Nephrology Division, Hospital General Juan Cardona, Avenida Pardo Bazán, s/n, Ferrol, 15406 A Coruña, Spain
| | - Carlos Fernández-Fernández
- Nephrology Division, Hospital General Juan Cardona, Avenida Pardo Bazán, s/n, Ferrol, 15406 A Coruña, Spain
| | - David Mouriño-Bayolo
- Nephrology Division, Hospital General Juan Cardona, Avenida Pardo Bazán, s/n, Ferrol, 15406 A Coruña, Spain
| | - Elvira Castro-Quintela
- Nephrology Division, Hospital General Juan Cardona, Avenida Pardo Bazán, s/n, Ferrol, 15406 A Coruña, Spain
| | - Alberto Domínguez-Montero
- Nephrology Division, Hospital General Juan Cardona, Avenida Pardo Bazán, s/n, Ferrol, 15406 A Coruña, Spain
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26
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Affiliation(s)
- E Marie Freel
- From the Institute of Cardiovascular & Medical Sciences (E.M.F.) and School of Medicine (C.G.P., P.O.D.), University of Glasgow, Glasgow, United Kingdom; Studies Coordinating Center, Research Unit Hypertension and Cardiovascular Sciences, University of Leuven, Leuven, Belgium (J.A.S.); Director's Research Group, Baker IDI Heart and Diabetes Institute, Melbourne, Australia (G.L.J.); Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson (J.P.G.); Department of Cardiology, Ghent University, Ghent, Belgium (M.D.B.); and Lady Davis Institute for Medical Research and Department of Medicine, Sir Mortimer B. Davis-Jewish General Hospital, McGill University, Montreal, Province of Quebec, Canada (E.L.S.).
| | - Colin G Perry
- From the Institute of Cardiovascular & Medical Sciences (E.M.F.) and School of Medicine (C.G.P., P.O.D.), University of Glasgow, Glasgow, United Kingdom; Studies Coordinating Center, Research Unit Hypertension and Cardiovascular Sciences, University of Leuven, Leuven, Belgium (J.A.S.); Director's Research Group, Baker IDI Heart and Diabetes Institute, Melbourne, Australia (G.L.J.); Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson (J.P.G.); Department of Cardiology, Ghent University, Ghent, Belgium (M.D.B.); and Lady Davis Institute for Medical Research and Department of Medicine, Sir Mortimer B. Davis-Jewish General Hospital, McGill University, Montreal, Province of Quebec, Canada (E.L.S.)
| | - Patrick O'Dwyer
- From the Institute of Cardiovascular & Medical Sciences (E.M.F.) and School of Medicine (C.G.P., P.O.D.), University of Glasgow, Glasgow, United Kingdom; Studies Coordinating Center, Research Unit Hypertension and Cardiovascular Sciences, University of Leuven, Leuven, Belgium (J.A.S.); Director's Research Group, Baker IDI Heart and Diabetes Institute, Melbourne, Australia (G.L.J.); Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson (J.P.G.); Department of Cardiology, Ghent University, Ghent, Belgium (M.D.B.); and Lady Davis Institute for Medical Research and Department of Medicine, Sir Mortimer B. Davis-Jewish General Hospital, McGill University, Montreal, Province of Quebec, Canada (E.L.S.)
| | - Jan A Staessen
- From the Institute of Cardiovascular & Medical Sciences (E.M.F.) and School of Medicine (C.G.P., P.O.D.), University of Glasgow, Glasgow, United Kingdom; Studies Coordinating Center, Research Unit Hypertension and Cardiovascular Sciences, University of Leuven, Leuven, Belgium (J.A.S.); Director's Research Group, Baker IDI Heart and Diabetes Institute, Melbourne, Australia (G.L.J.); Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson (J.P.G.); Department of Cardiology, Ghent University, Ghent, Belgium (M.D.B.); and Lady Davis Institute for Medical Research and Department of Medicine, Sir Mortimer B. Davis-Jewish General Hospital, McGill University, Montreal, Province of Quebec, Canada (E.L.S.)
| | - Garry L Jennings
- From the Institute of Cardiovascular & Medical Sciences (E.M.F.) and School of Medicine (C.G.P., P.O.D.), University of Glasgow, Glasgow, United Kingdom; Studies Coordinating Center, Research Unit Hypertension and Cardiovascular Sciences, University of Leuven, Leuven, Belgium (J.A.S.); Director's Research Group, Baker IDI Heart and Diabetes Institute, Melbourne, Australia (G.L.J.); Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson (J.P.G.); Department of Cardiology, Ghent University, Ghent, Belgium (M.D.B.); and Lady Davis Institute for Medical Research and Department of Medicine, Sir Mortimer B. Davis-Jewish General Hospital, McGill University, Montreal, Province of Quebec, Canada (E.L.S.)
| | - Joey P Granger
- From the Institute of Cardiovascular & Medical Sciences (E.M.F.) and School of Medicine (C.G.P., P.O.D.), University of Glasgow, Glasgow, United Kingdom; Studies Coordinating Center, Research Unit Hypertension and Cardiovascular Sciences, University of Leuven, Leuven, Belgium (J.A.S.); Director's Research Group, Baker IDI Heart and Diabetes Institute, Melbourne, Australia (G.L.J.); Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson (J.P.G.); Department of Cardiology, Ghent University, Ghent, Belgium (M.D.B.); and Lady Davis Institute for Medical Research and Department of Medicine, Sir Mortimer B. Davis-Jewish General Hospital, McGill University, Montreal, Province of Quebec, Canada (E.L.S.)
| | - Marc De Buyzere
- From the Institute of Cardiovascular & Medical Sciences (E.M.F.) and School of Medicine (C.G.P., P.O.D.), University of Glasgow, Glasgow, United Kingdom; Studies Coordinating Center, Research Unit Hypertension and Cardiovascular Sciences, University of Leuven, Leuven, Belgium (J.A.S.); Director's Research Group, Baker IDI Heart and Diabetes Institute, Melbourne, Australia (G.L.J.); Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson (J.P.G.); Department of Cardiology, Ghent University, Ghent, Belgium (M.D.B.); and Lady Davis Institute for Medical Research and Department of Medicine, Sir Mortimer B. Davis-Jewish General Hospital, McGill University, Montreal, Province of Quebec, Canada (E.L.S.)
| | - Ernesto L Schiffrin
- From the Institute of Cardiovascular & Medical Sciences (E.M.F.) and School of Medicine (C.G.P., P.O.D.), University of Glasgow, Glasgow, United Kingdom; Studies Coordinating Center, Research Unit Hypertension and Cardiovascular Sciences, University of Leuven, Leuven, Belgium (J.A.S.); Director's Research Group, Baker IDI Heart and Diabetes Institute, Melbourne, Australia (G.L.J.); Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson (J.P.G.); Department of Cardiology, Ghent University, Ghent, Belgium (M.D.B.); and Lady Davis Institute for Medical Research and Department of Medicine, Sir Mortimer B. Davis-Jewish General Hospital, McGill University, Montreal, Province of Quebec, Canada (E.L.S.)
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27
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Patra S, Nadri G, Chowdhary H, Pemde HK, Singh V, Chandra J. A case report of nephrogenic diabetes insipidus with idiopathic Fanconi syndrome in a child who presented with vitamin D resistant rickets. J Pediatr Endocrinol Metab 2014; 27:573-5. [PMID: 24821875 DOI: 10.1515/jpem.2011.042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Accepted: 06/18/2011] [Indexed: 11/15/2022]
Abstract
Fanconi syndrome is a complex of multiple tubular dysfunctions of proximal tubular cells, occurring alone or in association with a variety of inherited (primary) or acquired (secondary) disorders. It is characterized by aminoaciduria, normoglycemic glycosuria, tubular proteinuria without hematuria, metabolic acidosis without anion gap and excessive urinary excretion of phosphorous, calcium, uric acid, bicarbonate, sodium, potassium and magnesium. Diabetes insipidus is a disease of collecting tubules and children mainly present with dehydration and hypernatremia. We are reporting the first case of idiopathic Fanconi's syndrome along with nephrogenic diabetes insipidus in a child who presented to us with vitamin D resistant rickets. Medline search did not reveal any case of nephrogenic diabetes insipidus (NDI) associated with idiopathic Fanconi syndrome. We hypothesized that the NDI may be due to to severe hypokalemia induced tubular dysfunction.
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28
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Wang HH, Hung CC, Hwang DY, Kuo MC, Chiu YW, Chang JM, Tsai JC, Hwang SJ, Seifter JL, Chen HC. Hypokalemia, its contributing factors and renal outcomes in patients with chronic kidney disease. PLoS One 2013; 8:e67140. [PMID: 23843989 PMCID: PMC3699540 DOI: 10.1371/journal.pone.0067140] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Accepted: 05/14/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND In the chronic kidney disease (CKD) population, the impact of serum potassium (sK) on renal outcomes has been controversial. Moreover, the reasons for the potential prognostic value of hypokalemia have not been elucidated. DESIGN PARTICIPANTS & MEASUREMENTS 2500 participants with CKD stage 1-4 in the Integrated CKD care program Kaohsiung for delaying Dialysis (ICKD) prospective observational study were analyzed and followed up for 2.7 years. Generalized additive model was fitted to determine the cutpoints and the U-shape association between sK and end-stage renal disease (ESRD). sK was classified into five groups with the cutpoints of 3.5, 4, 4.5 and 5 mEq/L. Cox proportional hazard regression models predicting the outcomes were used. RESULTS The mean age was 62.4 years, mean sK level was 4.2±0.5 mEq/L and average eGFR was 40.6 ml/min per 1.73 m(2). Female vs male, diuretic use vs. non-use, hypertension, higher eGFR, bicarbonate, CRP and hemoglobin levels significantly correlated with hypokalemia. In patients with lower sK, nephrotic range proteinuria, and hypoalbuminemia were more prevalent but the use of RAS (renin-angiotensin system) inhibitors was less frequent. Hypokalemia was significantly associated with ESRD with hazard ratios (HRs) of 1.82 (95% CI, 1.03-3.22) in sK <3.5mEq/L and 1.67 (95% CI,1.19-2.35) in sK = 3.5-4 mEq/L, respectively, compared with sK = 4.5-5 mEq/L. Hyperkalemia defined as sK >5 mEq/L conferred 1.6-fold (95% CI,1.09-2.34) increased risk of ESRD compared with sK = 4.5-5 mEq/L. Hypokalemia was also associated with rapid decline of renal function defined as eGFR slope below 20% of the distribution range. CONCLUSION In conclusion, both hypokalemia and hyperkalemia are associated with increased risk of ESRD in CKD population. Hypokalemia is related to increased use of diuretics, decreased use of RAS blockade and malnutrition, all of which may impose additive deleterious effects on renal outcomes.
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Affiliation(s)
- Hsiao-Han Wang
- Division of Nephrology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
- Department of Dermatology, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Chi-Chih Hung
- Division of Nephrology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
- Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Daw-Yang Hwang
- Division of Nephrology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Mei-Chuan Kuo
- Division of Nephrology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
- Faculty of Renal Care, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Yi-Wen Chiu
- Division of Nephrology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
- Faculty of Renal Care, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Jer-Ming Chang
- Division of Nephrology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
- Department of Internal Medicine, Kaohsiung Municipal Hsiao-Kang Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
- Faculty of Renal Care, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Jer-Chia Tsai
- Division of Nephrology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
- Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Shang-Jyh Hwang
- Division of Nephrology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
- Faculty of Renal Care, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Julian L. Seifter
- Renal Division, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Hung-Chun Chen
- Division of Nephrology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
- Faculty of Renal Care, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- * E-mail:
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Matuszkiewicz-Rowińska J, Wojtaszek E. [Potassium homeostasis]. Wiad Lek 2013; 66:286-289. [PMID: 24490478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Potassium is a main cation in the intracellular compartment, with nearly 80% of stores being present in muscles, liver, bone and red blood cells. Intracellular potassium concentration is about 140-150 mmol/l in contrast to more than 30 times lower extracellular levels (3.5-5.0 mmol/l).This transmembrane gradient is crucial for maintenance of the membrane resting potential and neuro-muscularfunctioning, including the heart. In this review the physiological regulation of potassium balance is shortly reviewed to set a background for understanding its disorders.
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Affiliation(s)
| | - Ewa Wojtaszek
- Katedra i Klinika Nefrologii, Dializoterapii i Chorób Wewnetrznych, Warszawski Uniwersytet Medyczny
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Barna M, Wilson K, Chiaruttini R, Muchowski K. Diagnostic puzzler: hypertension in teen. J Fam Pract 2012; 61:536-539. [PMID: 23000661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Affiliation(s)
- Michael Barna
- Department of Family Medicine, Naval Hospital Camp Pendleton, CA 92055, USA.
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31
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Parker MD, Qin X, Williamson RC, Toye AM, Boron WF. HCO(3)(-)-independent conductance with a mutant Na(+)/HCO(3)(-) cotransporter (SLC4A4) in a case of proximal renal tubular acidosis with hypokalaemic paralysis. J Physiol 2012; 590:2009-34. [PMID: 22331414 PMCID: PMC3573318 DOI: 10.1113/jphysiol.2011.224733] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Accepted: 02/07/2012] [Indexed: 12/14/2022] Open
Abstract
The renal electrogenic Na(+)/HCO(3)(−) cotransporter (NBCe1-A) contributes to the basolateral step of transepithelial HCO(3)(−) reabsorption in proximal tubule epithelia, contributing to the buffering of blood pH. Elsewhere in the body (e.g. muscle cells) NBCe1 variants contribute to, amongst other processes, maintenance of intracellular pH. Others have described a homozygous mutation in NBCe1 (NBCe1-A p.Ala799Val) in an individual with severe proximal renal tubular acidosis (pRTA; usually associated with defective HCO(3)(−) reabsorption in proximal tubule cells) and hypokalaemic periodic paralysis (hypoPP; usually associated with leaky cation channels in muscle cells). Using biotinylation and two-electrode voltage-clamp on Xenopus oocytes expressing NBCe1, we demonstrate that the mutant NBCe1-A (A(A799V)) exhibits a per-molecule transport defect that probably contributes towards the observed pRTA. Furthermore, we find that A(A799V) expression is associated with an unusual HCO(3)(−)-independent conductance that, if associated with mutant NBCe1 in muscle cells, could contribute towards the appearance of hypokalaemic paralysis in the affected individual. We also study three novel lab mutants of NBCe1-A: p.Ala799Ile, p.Ala799Gly and p.Ala799Ser. All three exhibit a per-molecule transport defect, but only A(A799I) exhibits an A(A799V)-like ion conductance. A(A799G) and A(A799S) exhibit unusual outward rectification in their HCO(3)(−)-dependent conductance and A(A799G) exhibits reduced sensitivity to both DIDS and tenidap. A799G is the first mutation shown to affect the apparent tenidap affinity of NBCe1. Finally we show that A(A799V) and A(A799I), which accumulate poorly in the plasma membrane of oocytes, exhibit signs of abnormal intracellular accumulation in a non-polarized renal cell-line.
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Affiliation(s)
- Mark D Parker
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44106, USA.
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Abstract
Proton pump inhibitors (PPIs) act only in the stomach, although the proton pump, H(+),K(+)-ATPase exists and contributes to H(+) and K(+) homeostasis in the kidney. We encountered two hypokalemic cases receiving omeprazole. These cases were women ages 69 and 80 years old. Their serum potassium levels decreased with accelerated urinary potassium excretion with the use of omeprazole, and recovered by potassium-supplement and the discontinuation of omeprazole. Because inhibitory effects of PPIs on H(+),K(+)-ATPase are exerted only in acidic condition, hypokalemia is not generally introduced by PPIs alone. However, in extreme alkalosis or impaired K(+)-recycling system, PPIs may cause hypokalemia unrelated to hypomagnesemia.
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Affiliation(s)
- Yoshitaka Maeda
- Division of Nephrology, Department of Internal Medicine, Toride Kyodo General Hospital (JA Toride Medical Center, renamed on April 1, 2011), Japan.
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Sundar U, Lakkas Y, Asole D, Vaidya M. Gitelman's syndrome presenting as recurrent paralytic ileus due to chronic renal tubular K+ wasting. J Assoc Physicians India 2010; 58:322-324. [PMID: 21117354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Gitelman' syndrome, although a relatively frequent cause of chronic hypokalemia in adults, is rarely diagnosed correctly. It is frequently confused with overt diuretic abuse or Bartter's syndrome. We describe a 60 year man with 2 year history of recurrent paralytic ileus attributed to recurrent hypokalemia. Investigations in this patient revealed hypokalemia, metabolic alkalosis, hypocalciurea, and hypomagnesemia a tetrad diagnostic of Gitelman's syndrome. The peculiar clinical features of this condition and its management are discussed.
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Affiliation(s)
- Uma Sundar
- Internal Medicine, Service, Lokmanya Tilak Municipal General Hospital and Medical College, Mumbai, India
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Abstract
BACKGROUND/AIMS The consumption of soft drinks has increased considerably during the last decades. Among them, the cola-based preparations are possibly the refreshments with the largest sales worldwide. In addition to the possible detrimental effects of moderate, chronic cola consumption, it has been proposed that the consumption of large amounts of cola-based soft drinks may result in severe hypokalaemia. METHODS In this review, we discuss the clinical significance of these disturbances and summarise the pathophysiological mechanism that may underlie the development of this rare, but potentially severe, side effect. RESULTS/CONCLUSION Several lines of evidence suggest that the chronic consumption of large amounts of cola soft drinks may adversely affect potassium homeostasis and result in potentially severe conditions such as hypokalaemic myopathy.
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Affiliation(s)
- V Tsimihodimos
- Department of Internal Medicine, Medical School, University of Ioannina, Ioannina, Greece
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Abstract
Humans are intermittently exposed to large variations in potassium intake, which range from periods of fasting to ingestion of potassium-rich meals. These fluctuations would abruptly alter plasma potassium concentration if not for rapid mechanisms, primarily in skeletal muscle and the liver, that buffer the changes in plasma potassium concentration by means of transcellular potassium redistribution and feedback control of renal potassium excretion. However, buffers have capacity limits, and even robust feedback control mechanisms require that the perturbation occur before feedback can initiate corrective action. In contrast, feedforward control mechanisms sense the effect of disturbances on the system's homeostasis. This review highlights recent experimental insights into the participation of feedback and feedforward control mechanisms in potassium homeostasis. New data make clear that feedforward homeostatic responses activate when decreased potassium intake is sensed, even when plasma potassium concentration is still within the normal range and before frank hypokalemia ensues, in addition to the classic feedback activation of renal potassium conservation when plasma potassium concentration decreases. Given the clinical importance of dyskalemias in patients, these novel experimental paradigms invite renewed clinical inquiry into this important area.
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Affiliation(s)
- Megan Greenlee
- University of Florida College of Medicine and Department of Veterans Affairs Medical Center, Gainesville, Florida 32610, USA
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Abstract
Arrhythmias induced by digitalis are believed to be secondary to changes in ion concentrations in the myocardial cells or changes in the transcellular ion gradient. Both diuretic induced hypokalemia and digitalis inhibit the membrane-Na+K+ ATPase activity which cause a decrease of the intracellular potassium concentration. This may explain the risk of cardiac arrhythmias during digitalis treatment and during severe hypokalemia, and may further explain the increase for myocardial sensitivity for digitalis when hypokalemia is present. The myocardial uptake of digitalis however is markedly increased at low extracellular potassium concentration and this may be the explanation of the interaction between digitalis and hypokalemia. Not only the myocardial digoxin kinetic is changed during hypokalemia but the renal excretion rate of digoxin is markedly reduced during hypokalemia leading to increased serum digoxin concentration and thereby the risk of digitalis intoxication.
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Dyckner T, Wester PO. The relation between extra- and intracellular electrolytes in patients with hypokalemia and/or diuretic treatment. Acta Med Scand 2009; 204:269-82. [PMID: 696427 DOI: 10.1111/j.0954-6820.1978.tb08438.x] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The relation between extra- and intracellular electrolytes has been studied by means of percutaneous muscle biopsies in 107 patients with hypokalemia and/or treatment with diuretics. No relation was found between the extra- and intracellular concentrations of Na or Mg. The serum and muscle contents of K correlated weakly. The correlation coefficient tended to be stronger when S-creatinine was normal, total carbonate was between 25 and 30 mmol/l, muscle Mg content was greater than or equal to 3.95 mmol/100 g fat free dry solids, and when no treatment was given with digitalis and/or diuretics.
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Dyckner T, Wester PO. Ventricular extrasystoles and intracellular electrolytes in hypokalemic patients before and after correction of the hypokalemia. Acta Med Scand 2009; 204:375-9. [PMID: 82374 DOI: 10.1111/j.0954-6820.1978.tb08458.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Fifty-four initially hypokalemic patients, 43 of whom were on diuretic treatment, were given potassium supplementation until they showed a repeatedly normal serum potassium level. Muscle specimens obtained by percutaneous biopsy revealed that there were no concomitant increases in muscle potassium content, nor in intracellular potassium concentration, except in the very small group (6 patients) with a muscle magnesium content of greater than or equal to 3.95 mmol/100 g fat free dry solids (FFDS) and an initially lower muscle potassium content (less than or equal to 39.9 mmol/100 g FFDS). ECG, registered for 3 hours on a portable ECG tape recorder before and after correction of the serum potassium level, showed no change in the frequency of ventricular ectopic beats.
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Dyckner T, Wester PO. Potassium-sparing diuretics. Acta Med Scand Suppl 2009; 707:79-83. [PMID: 3461689 DOI: 10.1111/j.0954-6820.1986.tb18120.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The hemodynamic and the endocrine disturbances in congestive heart failure (CHF) impose major changes in electrolyte balance with a retention of sodium and concomitant losses of potassium and magnesium from the body. These changes are of great importance for the development of cardiac dysrhythmias, a diminished glucose tolerance and for the well-being of the patient. The use of conventional diuretics imposes further burdens on the already deranged electrolyte balance. On long-term therapy with conventional diuretics in CHF we observed that approximately 50% of the 297 patients studied had potassium and magnesium deficiencies and an increased sodium content as judged by skeletal muscle biopsies. The magnesium deficiency is especially dangerous since it prevents the cells from keeping their high intracellular potassium concentration unchanged. Potassium substitution is without effect in a magnesium deficiency since magnesium is necessary for the transportation of potassium over the cell membrane against the concentration gradient. In case of magnesium depletion, potassium substitution may even have negative effects on the body potassium content. The reason for this is probably the increase of p-potassium concentration induced by the substitution, leading to an increase of aldosterone secretion. An increase of p-potassium levels by 0.2-0.4 mmol/l may thus result in a 50-100% rise in p-aldosterone concentration. These changes promote further urinary losses of potassium and magnesium. Several studies have demonstrated the positive effects of the potassium-sparing diuretics amiloride, spironolactone and triamterene on p-potassium concentration, but also on the body potassium content.(ABSTRACT TRUNCATED AT 250 WORDS)
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Eckardstein AV. [CME-Laboratory 10/ Solution on the subject "Disorders of electrolyte and water balance"]. Praxis (Bern 1994) 2009; 98:349-351. [PMID: 19291646 DOI: 10.1024/1661-8157.98.6.349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
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Ruete MC, Carrizo LC, Bocanegra MV, Vallés PG. Altered renal expression of Na(+) transporters and ROMK in protein-deprived rats. Nephron Physiol 2009; 111:p17-p29. [PMID: 19202345 DOI: 10.1159/000199462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2008] [Accepted: 09/26/2008] [Indexed: 05/27/2023]
Abstract
Potassium depletion has been associated with altered sodium reabsorption in tubule segments. We studied if the altered abundance of Na(+) transporters and ROMK are associated with distal potassium secretion that contributes to the development of hypokalemia in protein-deprived rats. After weaning, Wistar rats were fed with a low-protein diet (8%, LP) for 14 days and then recovered with a normal-protein (NP) diet (24%, RP). An age-matched control group was fed with an NP diet (24%, NP). We showed hypokalemia, lower glomerular filtration rate and higher FEK(+) in the LP group. Immunoblotting revealed that the type 3 Na(+)/H(+) exchanger in the cortex was decreased in the LP group. However, the type 2 Na(+)-K(+)-2Cl(-) cotransporter was increased in the outer stripe of the outer medulla in the LP group. The abundance of the aldosterone-regulated Na(+)-Cl(-) cotransporter (NCC) and epithelial Na(+) channel (ENaC) was higher in the LP group and was associated with higher plasma aldosterone level. ROMK protein levels were increased. Na(+)/K(+)-ATPase protein levels were the same in both groups. After the recovery period, the expression of Na(+) transporters and ROMK returned to control values. We conclude that increased expression of NCC, ENaC subunits, and ROMK contributed to distal potassium secretion leading to enhanced potassium excretion, which may explain the hypokalemia resulting from LP feeding. A role of aldosterone may be suggested.
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Affiliation(s)
- María Celeste Ruete
- IMBECU-CONICET (Consejo Nacional de Investigaciones Científicas y Tecnológicas), Mendoza, Argentina
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43
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Ma L, Yang L, Jin Y, Chen X. [The effects of hypokalemia on the Na+ channel in cardiac tissue--a computer simulation study]. Sheng Wu Yi Xue Gong Cheng Xue Za Zhi 2009; 26:1-5. [PMID: 19334542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In order to explore the reason why hypokalemia could increase the vulnerable window (VW) for unidirectional conduction block in Long QT Syndromes (LQTS), we observed the effect of hypokalemia on the spatial gradients of Na channel conductance (G(Na)) and gating factors by using the LR91 1-dimensional heterogeneous virtual cardiac ventricular tissue model quatitively. The computer simulation experiments were divided into two groups, namely control and LQTS groups. The action potential was elicited after the basic stimulus S1 (-70 microA/microF, 1.5 ms) was given 10 times with basic cycle length (BCL) 500, 1000 and 2000 ms. To test the VW in unit of time (VWtime), the S1-S2 programmed stimuli were used with shortening S1S2 interval at the decrement of 1 ms. At the same time, the spatial gradients of Na channel conductance (G(Na)) and gating factors, m, h, j, were investigated. The APD and ionic channel currents were also detected under the conditions of normal and lower concentration of K+ outside of cell. We found that hypokalemia, LQTS and slow pacing rate enhanced the spatial gradient of G(Na) by increasing the spatial gradient of inactive gating factors h x j. The results also showed that hypokalemia deduced the peak values of I(K) and I(K1), which prolonged the action potential duration and enlarged the repolarization dispersion in this 1-D tissue cable model. Possibly these are the important factors to cause the spatial gradient of h x j and G(Na). enlargement. These changes increase the incidence of unidirectional conduction block of VW, and are vital reasons to increase the possibility of ventricular arrhythmia generation.
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Affiliation(s)
- Li Ma
- Department of Cardiology, First Hospital, Xi'an Jiaotong University, Xi'an 710061, China
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44
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Hoskote SS, Joshi SR, Ghosh AK. Disorders of potassium homeostasis: pathophysiology and management. J Assoc Physicians India 2008; 56:685-693. [PMID: 19086355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Disorders of potassium homeostasis are common electrolyte abnormalities encountered in hospitalized patients. Hypokalemia and hyperkalemia have been estimated to occur in about 21% and 3% of hospitalized patients, respectively; though the morbidity and mortality associated with the latter is significantly higher. Potassium is a predominantly intracellular ion and the understanding of its dynamics between intra- and extracellular fluid milieus, along with its handling by the kidneys, is important in the diagnosis and treatment of potassium disorders. This article aims to provide a clinically relevant update on management of potassium disorders for internists.
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Abstract
Theophylline is commonly used in the treatment of bronchospastic lung disease. In addition to gastrointestinal and cardiac dysfunction, hypokalaemia, lactic and ketoacidosis can complicate theophylline overdose. Clinicians frequently fail to identify theophylline's role when complications develop. A case of an 80-year-old man who developed profound metabolic disturbances while hospitalized is presented. The typical causes of these abnormalities were absent, theophylline levels were elevated, and the patient recovered after theophylline was held. Based on our case and review of the literature, we discuss the reasons why theophylline toxicity is under-recognized, and propose mechanisms for the rare metabolic abnormalities identified in this case. A high index of suspicion for theophylline toxicity should be maintained and it should be considered when unexplained acidosis or hypokalaemia occur.
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Affiliation(s)
- David Charytan
- Beth Israel Deaconess Medical Center, Boston, Massachussets 00215, USA.
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46
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Muto S, Kusano E. [Approach to disorders of potassium metabolism]. Nihon Jinzo Gakkai Shi 2008; 50:84-90. [PMID: 18421963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
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47
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Affiliation(s)
- Rengasayee Veeraraghavan
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT 84112-5000, USA
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48
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Kanazawa I, Yamamoto M, Yamaguchi T, Yamauchi M, Yano S, Sugimoto T. A case of magnesium deficiency associated with insufficient parathyroid hormone action and severe osteoporosis. Endocr J 2007; 54:935-40. [PMID: 18048993 DOI: 10.1507/endocrj.k07-040] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The relationship between osteoporosis and magnesium (Mg) deficiency is still controversial. Here we report a case of an 82-year-old woman with a giant adenomatous goiter and severe osteoporosis with multiple vertebral fractures, whose clinical course indicated that her osteoporosis was probably due to Mg deficiency. She visited our hospital for treatments of tetany. Laboratory data showed the existence of hypomagnesemia, hypocalcemia, hypokalemia, vitamin D deficiency, and slightly elevated intact PTH. Intravenous administration of Mg not only improved these electrolyte abnormalities but also increased serum levels of intact PTH, bone formation markers, 1,25-dihydroxyvitamin D, as well as bone resorption markers in the urine, and lowered urinary phosphate reabsorption. Hypomagnesemia on admission seemed to arise from long-lasting poor food intake and malnutrition, because it improved after the disappearance of dysphagia with a goiter resection. After the operation, BMD values at the lumbar spine and femoral neck obviously increased during 6 months of Mg supplementation without any specific therapies for osteoporosis. Mg deficiency in this case seemed to cause impaired secretion of PTH from the parathyroid and the refractoriness of bone and kidney to the hormone, which led to the suppression of both bone remodeling and renal vitamin D production. These processes were probably linked to her severe osteoporosis, which was reversed by Mg supplementation.
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Affiliation(s)
- Ippei Kanazawa
- Department of Internal Medicine 1, Shimane University Faculty of Medicine, Shimane, Japan
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Abstract
Magnesium deficiency is frequently associated with hypokalemia. Concomitant magnesium deficiency aggravates hypokalemia and renders it refractory to treatment by potassium. Herein is reviewed literature suggesting that magnesium deficiency exacerbates potassium wasting by increasing distal potassium secretion. A decrease in intracellular magnesium, caused by magnesium deficiency, releases the magnesium-mediated inhibition of ROMK channels and increases potassium secretion. Magnesium deficiency alone, however, does not necessarily cause hypokalemia. An increase in distal sodium delivery or elevated aldosterone levels may be required for exacerbating potassium wasting in magnesium deficiency.
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Affiliation(s)
- Chou-Long Huang
- UT Southwestern Medical Center, Department of Medicine, 5323 Harry Hines Boulevard, Dallas, TX 75390-8856, USA.
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50
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Killeen MJ, Gurung IS, Thomas G, Stokoe KS, Grace AA, Huang CLH. Separation of early afterdepolarizations from arrhythmogenic substrate in the isolated perfused hypokalaemic murine heart through modifiers of calcium homeostasis. Acta Physiol (Oxf) 2007; 191:43-58. [PMID: 17524066 PMCID: PMC2040229 DOI: 10.1111/j.1748-1716.2007.01715.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
AIMS We resolved roles for early afterdepolarizations (EADs) and transmural gradients of repolarization in arrhythmogenesis in Langendorff-perfused hypokalaemic murine hearts paced from the right ventricular epicardium. METHODS Left ventricular epicardial and endocardial monophasic action potentials (MAPs) and arrhythmogenic tendency were compared in the presence and absence of the L-type Ca(2+) channel blocker nifedipine (10 nm-1 microm) and the calmodulin kinase type II inhibitor KN-93 (2 microm). RESULTS All the hypokalaemic hearts studied showed prolonged epicardial and endocardial MAPs, decreased epicardial-endocardial APD(90) difference, EADs, triggered beats and ventricular tachycardia (VT) (n = 6). In all spontaneously beating hearts, 100 (but not 10) nm nifedipine reduced both the incidence of EADs and triggered beats from 66.9 +/- 15.7% to 28.3 +/- 8.7% and episodes of VT from 10.8 +/- 6.3% to 1.2 +/- 0.7% of MAPs (n = 6 hearts, P < 0.05); 1 microm nifedipine abolished all these phenomena (n = 6). In contrast programmed electrical stimulation (PES) still triggered VT in six of six hearts with 0, 10 and 100 nm but not 1 microm nifedipine. 1 microm nifedipine selectively reduced epicardial (from 66.1 +/- 3.4 to 46.2 +/- 2.5 ms) but not endocardial APD(90), thereby restoring DeltaAPD(90) from -5.9 +/- 2.5 to 15.5 +/- 3.2 ms, close to normokalaemic values. KN-93 similarly reduced EADs, triggered beats and VT in spontaneously beating hearts to 29.6 +/- 8.9% and 1.7 +/- 1.1% respectively (n = 6) yet permitted PES-induced VT (n = 6), in the presence of a persistently negative DeltaAPD(90). CONCLUSIONS These findings empirically implicate both EADs and triggered beats alongside arrhythmogenic substrate of DeltaAPD(90) in VT pathogenesis at the whole heart level.
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Affiliation(s)
- M J Killeen
- Physiological Laboratory, University of Cambridge, Cambridge, UK.
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