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Duan XP, Zhang CB, Wang WH, Lin DH. Role of calcineurin in regulating renal potassium (K +) excretion: Mechanisms of calcineurin inhibitor-induced hyperkalemia. Acta Physiol (Oxf) 2024:e14189. [PMID: 38860527 DOI: 10.1111/apha.14189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 05/28/2024] [Accepted: 05/30/2024] [Indexed: 06/12/2024]
Abstract
Calcineurin, protein phosphatase 2B (PP2B) or protein phosphatase 3 (PP3), is a calcium-dependent serine/threonine protein phosphatase. Calcineurin is widely expressed in the kidney and regulates renal Na+ and K+ transport. In the thick ascending limb, calcineurin plays a role in inhibiting NKCC2 function by promoting the dephosphorylation of the cotransporter and an intracellular sorting receptor, called sorting-related-receptor-with-A-type repeats (SORLA), is involved in modulating the effect of calcineurin on NKCC2. Calcineurin also participates in regulating thiazide-sensitive NaCl-cotransporter (NCC) in the distal convoluted tubule. The mechanisms by which calcineurin regulates NCC include directly dephosphorylation of NCC, regulating Kelch-like-3/CUL3 E3 ubiquitin-ligase complex, which is responsible for WNK (with-no-lysin-kinases) ubiquitination, and inhibiting Kir4.1/Kir5.1, which determines NCC expression/activity. Finally, calcineurin is also involved in regulating ROMK (Kir1.1) channels in the cortical collecting duct and Cyp11 2 expression in adrenal zona glomerulosa. In summary, calcineurin is involved in the regulation of NKCC2, NCC, and inwardly rectifying K+ channels in the kidney, and it also plays a role in modulating aldosterone synthesis in adrenal gland, which regulates epithelial-Na+-channel expression/activity. Thus, application of calcineurin inhibitors (CNIs) is expected to abrupt calcineurin-mediated regulation of transepithelial Na+ and K+ transport in the kidney. Consequently, CNIs cause hypertension, compromise renal K+ excretion, and induce hyperkalemia.
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Affiliation(s)
- Xin-Peng Duan
- Department of Physiology, Xuzhou Medical University, Xuzhou, China
| | - Cheng-Biao Zhang
- Department of Physiology, Xuzhou Medical University, Xuzhou, China
- 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
| | - Dao-Hong Lin
- Department of Pharmacology, New York Medical College, Valhalla, New York, USA
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2
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Schilling K, Chen H, Glabonjat RA, Debernardi S, Blyuss O, Navas-Acien A, Halliday AN, Crnogorac-Jurcevic T. Analysis of urinary potassium isotopes and association with pancreatic health: healthy, diabetic and cancerous states. Front Endocrinol (Lausanne) 2024; 15:1332895. [PMID: 38694937 PMCID: PMC11062322 DOI: 10.3389/fendo.2024.1332895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Accepted: 03/01/2024] [Indexed: 05/04/2024] Open
Abstract
Background More than 700 million people worldwide suffer from diseases of the pancreas, such as diabetes, pancreatitis and pancreatic cancer. Often dysregulation of potassium (K+) channels, co-transporters and pumps can promote development and progression of many types of these diseases. The role of K+ transport system in pancreatic cell homeostasis and disease development remains largely unexplored. Potassium isotope analysis (δ41K), however, might have the potential to detect minute changes in metabolic processes relevant for pancreatic diseases. Methods We assessed urinary K isotope composition in a case-control study by measuring K concentrations and δ41K in spot urines collected from patients diagnosed with pancreatic cancer (n=18), other pancreas-related diseases (n=14) and compared those data to healthy controls (n=16). Results Our results show that urinary K+ levels for patients with diseased pancreas (benign and pancreatic cancer) are significantly lower than the healthy controls. For δ41K, the values tend to be higher for individuals with pancreatic cancer (mean δ41K = -0.58 ± 0.33‰) than for healthy individuals (mean δ41K = -0.78 ± 0.19‰) but the difference is not significant (p=0.08). For diabetics, urinary K+ levels are significantly lower (p=0.03) and δ41K is significantly higher (p=0.009) than for the healthy controls. These results suggest that urinary K+ levels and K isotopes can help identify K disturbances related to diabetes, an associated factors of all-cause mortality for diabetics. Conclusion Although the K isotope results should be considered exploratory and hypothesis-generating and future studies should focus on larger sample size and δ41K analysis of other K-disrupting diseases (e.g., chronic kidney disease), our data hold great promise for K isotopes as disease marker.
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Affiliation(s)
- Kathrin Schilling
- Department of Environmental Health Sciences, Columbia University Mailman School of Public Health, New York, NY, United States
- Lamont‐Doherty Earth Observatory, Columbia University, Palisades, NY, United States
| | - Heng Chen
- Lamont‐Doherty Earth Observatory, Columbia University, Palisades, NY, United States
| | - Ronald A. Glabonjat
- Department of Environmental Health Sciences, Columbia University Mailman School of Public Health, New York, NY, United States
| | - Silvana Debernardi
- Centre for Cancer Biomarkers and Biotherapeutics, Barts Cancer Institute, Queen Mary University of London, London, United Kingdom
| | - Oleg Blyuss
- Wolfson’s Institute for Cancer Prevention, Queen Mary University of London, London, United Kingdom
| | - Ana Navas-Acien
- Department of Environmental Health Sciences, Columbia University Mailman School of Public Health, New York, NY, United States
| | - Alex N. Halliday
- Lamont‐Doherty Earth Observatory, Columbia University, Palisades, NY, United States
| | - Tatjana Crnogorac-Jurcevic
- Centre for Cancer Biomarkers and Biotherapeutics, Barts Cancer Institute, Queen Mary University of London, London, United Kingdom
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Sevamontree C, Jintajirapan S, Phakdeekitcharoen P, Phakdeekitcharoen B. The Prevalence and Risk Factors of Hyperkalemia in the Outpatient Setting. Int J Nephrol 2024; 2024:5694131. [PMID: 38292832 PMCID: PMC10824579 DOI: 10.1155/2024/5694131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 06/06/2023] [Accepted: 11/20/2023] [Indexed: 02/01/2024] Open
Abstract
Background Hyperkalemia is a life-threatening condition in outpatient and emergency departments. Hyperkalemia is associated with more events of major adverse cardiovascular diseases, hospitalization, and death. The aim of this study is to study and assess the prevalence and risk factors for developing hyperkalemia within the Thai population. Method A cross-sectional observational study of 3,299 unique adult patients (≥18 years) in one calendar year (2021) with at least 1 valid serum potassium (SK) test was conducted in the outpatient department of medicine. Hyperkalemia was determined as SK ≥5.8 mmol/L without hemolysis or technical error. Clinical data and laboratory tests were collected for analysis of risk factors. Result 2,971 patients (131 hyperkalemia and 2,840 control) were eligible. The annual prevalence of hyperkalemia was 4.41%. The mean ages of patients were 66.5 years in the hyperkalemia group and 55.9 years in the control group. Increasing age had a positive association (r = 0.220, p < 0.001) to risk of hyperkalemia, whereas the estimated glomerular filtration rate (eGFR) had an inverse association with SK level (r = -0.398, p < 0.001). The risk factors for hyperkalemia were patients with age ≥65 years (odds ratio, 2.106; 95% CI, 1.399, 3.171; p < 0.001), presence of diabetes mellitus (DM, odds ratio, 1.541; 95% CI, 1.030, 2.306; p = 0.036), chronic kidney disease (CKD) stage ≥3 (odds ratio, 14.885; 95% CI, 8.112, 27.313; p < 0.001), hemodialysis treatment (odds ratio, 10.170; 95% CI, 5.858, 17.657; p < 0.001), and usage of renin-angiotensin-aldosterone system inhibitors (RAASi, odds ratio, 2.256; 95% CI, 1.440, 3.536; p < 0.001). Conclusion The risk factors contributing to hyperkalemia were patients with older age, DM, CKD, hemodialysis treatment, and usage of RAASi. Although the usage of RAASi is proven to be a cardiovascular advantage in the elderly, DM, and CKD patients, careful monitoring of SK is strongly advised to optimize patient care.
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Affiliation(s)
- Chadapa Sevamontree
- Division of Nephrology, Department of Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Supreeya Jintajirapan
- Outpatient Intervention and Urgency Care, Department of Nursing, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | | | - Bunyong Phakdeekitcharoen
- Division of Nephrology, Department of Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
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Tacail T, Lewis J, Clauss M, Coath CD, Evershed R, Albalat E, Elliott TR, Tütken T. Diet, cellular, and systemic homeostasis control the cycling of potassium stable isotopes in endothermic vertebrates. Metallomics 2023; 15:mfad065. [PMID: 37858308 DOI: 10.1093/mtomcs/mfad065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 10/18/2023] [Indexed: 10/21/2023]
Abstract
The naturally occurring stable isotopes of potassium (41K/39K, expressed as δ41K) have the potential to make significant contributions to vertebrate and human biology. The utility of K stable isotopes is, however, conditioned by the understanding of the dietary and biological factors controlling natural variability of δ41K. This paper reports a systematic study of K isotopes in extant terrestrial endothermic vertebrates. δ41K has been measured in 158 samples of tissues, biofluids, and excreta from 40 individuals of four vertebrate species (rat, guinea pig, pig and quail) reared in two controlled feeding experiments. We show that biological processing of K by endothermic vertebrates produces remarkable intra-organism δ41K variations of ca. 1.6‰. Dietary δ41K is the primary control of interindividual variability and δ41K of bodily K is +0.5-0.6‰ higher than diet. Such a trophic isotope effect is expected to propagate throughout trophic chains, opening promising use for reconstructing dietary behaviors in vertebrate ecosystems. In individuals, cellular δ41K is related to the intensity of K cycling and effectors of K homeostasis, including plasma membrane permeability and electrical potential. Renal and intestinal transepithelial transports also control fractionation of K isotopes. Using a box-modeling approach, we establish a first model of K isotope homeostasis. We predict a strong sensitivity of δ41K to variations of intracellular and renal K cycling in normal and pathological contexts. Thus, K isotopes constitute a promising tool for the study of K dyshomeostasis.
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Affiliation(s)
- T Tacail
- Institute of Geosciences, Johannes Gutenberg University, J.-J.-Becher-Weg 21, D-55128, Mainz, Germany
- School of Earth Sciences, University of Bristol, Bristol, UK
| | - J Lewis
- School of Earth Sciences, University of Bristol, Bristol, UK
| | - M Clauss
- Clinic for Zoo Animals, Exotic Pets and Wildlife, Vetsuisse Faculty, University of Zurich, Switzerland
| | - C D Coath
- School of Earth Sciences, University of Bristol, Bristol, UK
| | - R Evershed
- Organic Geochemistry Unit, School of Chemistry, University of Bristol, UK
| | - E Albalat
- ENS de LYON, Universite Claude Bernard Lyon1, LGL-TPE, CNRS UMR 5276, Lyon, France
| | - T R Elliott
- School of Earth Sciences, University of Bristol, Bristol, UK
| | - T Tütken
- Institute of Geosciences, Johannes Gutenberg University, J.-J.-Becher-Weg 21, D-55128, Mainz, Germany
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5
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Wouda RD, Gritter M, Karsten M, Michels EH, Nieuweboer TM, Danser AJ, de Borst MH, Hoorn EJ, Rotmans JI, Vogt L. Kaliuresis and Intracellular Uptake of Potassium with Potassium Citrate and Potassium Chloride Supplements: A Randomized Controlled Trial. Clin J Am Soc Nephrol 2023; 18:1260-1271. [PMID: 37382933 PMCID: PMC10578626 DOI: 10.2215/cjn.0000000000000228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 06/21/2023] [Indexed: 06/30/2023]
Abstract
BACKGROUND A potassium replete diet is associated with lower cardiovascular risk but may increase the risk of hyperkalemia, particularly in people using renin-angiotensin-aldosterone system inhibitors. We investigated whether intracellular uptake and potassium excretion after an acute oral potassium load depend on the accompanying anion and/or aldosterone and whether this results in altered plasma potassium change. METHODS In this placebo-controlled interventional cross-over trial including 18 healthy individuals, we studied the acute effects of one oral load of potassium citrate (40 mmol), potassium chloride (40 mmol), and placebo in random order after overnight fasting. Supplements were administered after a 6-week period with and without lisinopril pretreatment. Linear mixed effect models were used to compare blood and urine values before and after supplementation and between the interventions. Univariable linear regression was used to determine the association between baseline variables and change in blood and urine values after supplementation. RESULTS During the 4-hour follow-up, the rise in plasma potassium was similar for all interventions. After potassium citrate, both red blood cell potassium-as measure of the intracellular potassium-and transtubular potassium gradient (TTKG)-reflecting potassium secretory capacity-were higher than after potassium chloride or potassium citrate with lisinopril pretreatment. Baseline aldosterone was significantly associated with TTKG after potassium citrate, but not after potassium chloride or potassium citrate with lisinopril pretreatment. The observed TTKG change after potassium citrate was significantly associated with urine pH change during this intervention ( R =0.60, P < 0.001). CONCLUSIONS With similar plasma potassium increase, red blood cell potassium uptake and kaliuresis were higher after an acute load of potassium citrate as compared with potassium chloride alone or pretreatment with lisinopril. CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER Potassium supplementation in patients with chronic kidney disease and healthy subjects: effects on potassium and sodium balance, NL7618.
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Affiliation(s)
- Rosa D. Wouda
- Department of Internal Medicine, Section of Nephrology, Amsterdam University Medical Centers, Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands
| | - Martin Gritter
- Department of Internal Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Micky Karsten
- Department of Internal Medicine, Section of Nephrology, Amsterdam University Medical Centers, Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands
| | - Erik H.A. Michels
- Department of Internal Medicine, Section of Nephrology, Amsterdam University Medical Centers, Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands
| | - Tamar M. Nieuweboer
- Department of Internal Medicine, Section of Nephrology, Amsterdam University Medical Centers, Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands
| | - A.H. Jan Danser
- Vascular Medicine and Pharmacology, Department of Internal Medicine, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Martin H. de Borst
- Department of Internal Medicine, Division of Nephrology, University Medical Center Groningen, Groningen, The Netherlands
| | - Ewout J. Hoorn
- Department of Internal Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Joris I. Rotmans
- Department of Internal Medicine, Division of Nephrology, Leiden University Medical Center, Leiden, The Netherlands
| | - Liffert Vogt
- Department of Internal Medicine, Section of Nephrology, Amsterdam University Medical Centers, Amsterdam Cardiovascular Sciences, Amsterdam, The Netherlands
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Kettritz R, Loffing J. Potassium homeostasis - Physiology and pharmacology in a clinical context. Pharmacol Ther 2023; 249:108489. [PMID: 37454737 DOI: 10.1016/j.pharmthera.2023.108489] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 07/03/2023] [Accepted: 07/06/2023] [Indexed: 07/18/2023]
Abstract
Membrane voltage controls the function of excitable cells and is mainly a consequence of the ratio between the extra- and intracellular potassium concentration. Potassium homeostasis is safeguarded by balancing the extra-/intracellular distribution and systemic elimination of potassium to the dietary potassium intake. These processes adjust the plasma potassium concentration between 3.5 and 4.5 mmol/L. Several genetic and acquired diseases but also pharmacological interventions cause dyskalemias that are associated with increased morbidity and mortality. The thresholds at which serum K+ not only associates but also causes increased mortality are hotly debated. We discuss physiologic, pathophysiologic, and pharmacologic aspects of potassium regulation and provide informative case vignettes. Our aim is to help clinicians, epidemiologists, and pharmacologists to understand the complexity of the potassium homeostasis in health and disease and to initiate appropriate treatment strategies in dyskalemic patients.
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Affiliation(s)
- Ralph Kettritz
- Department of Nephrology and Medical Intensive Care, Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany; Experimental and Clinical Research Center, Max Delbrück Center for Molecular Medicine in the Helmholtz Association and Charité Universitätsmedizin Berlin, Germany.
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7
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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] [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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8
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Agiro A, AN A, Cook EE, Mu F, Chen J, Desai P, Oluwatosin Y, Pollack CV. Real-World Modifications of Renin-Angiotensin-Aldosterone System Inhibitors in Patients with Hyperkalemia Initiating Sodium Zirconium Cyclosilicate Therapy: The OPTIMIZE I Study. Adv Ther 2023; 40:2886-2901. [PMID: 37140706 PMCID: PMC10220114 DOI: 10.1007/s12325-023-02518-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 04/06/2023] [Indexed: 05/05/2023]
Abstract
INTRODUCTION Hyperkalemia (HK) may result in disruptions of guidelines-concordant renin-angiotensin-aldosterone system inhibitors (RAASi), a standard of care in persons with chronic kidney disease (CKD). Such disruptions-dose reduction or discontinuation-diminish the benefits of RAASi, placing patients at risk of serious events and renal dysfunction. This real-world study evaluated RAASi modifications among patients who initiated sodium zirconium cyclosilicate (SZC) for HK. METHODS Adults (≥ 18 years) initiating outpatient SZC (index date) while on RAASi were identified from a large US claims database (January 2018-June 2020). RAASi optimization (maintain same or up-titration of RAASi dosage), non-optimization (down-titration of RAASi dosage or discontinuation), and persistence were descriptively summarized following index. Predictors of RAASi optimization were assessed using multivariable logistic regression models. Analyses were conducted by subgroups, including patients without end-stage kidney disease (ESKD), with CKD, and with CKD + diabetes. RESULTS A total of 589 patients initiated SZC during RAASi therapy (mean age 61.0 years, 65.2% male), and 82.7% patients (n = 487) kept RAASi after index (mean follow-up = 8.1 months). Most patients (77.4%) optimized RAASi therapy after initiating SZC; 69.6% maintained the same dosage while 7.8% had up-titrations. A similar rate of RAASi optimization was observed among subgroups without ESKD (78.4%), with CKD (78.9%), and with CKD + diabetes (78.1%). At 1-year post-index, 73.9% of all patients who optimized RAASi were still on therapy, while only 17.9% of patients who did not optimize therapy were still on a RAASi. Among all patients, predictors of RAASi optimization included fewer prior hospitalizations (odds ratio = 0.79, 95% CI [0.63-1.00]; p < 0.05) and fewer prior emergency department (ED) visits (0.78 [0.63-0.96]; p < 0.05). CONCLUSION Consistent with clinical trial findings, nearly 80% of patients who initiated SZC for HK optimized their RAASi therapy. Patients may require long-term SZC therapy to encourage continuation of RAASi therapy especially after inpatient and ED visits.
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Affiliation(s)
- Abiy Agiro
- AstraZeneca, US Medical Affairs, 1800 Concord Pike, Wilmington, DE 19850 USA
| | - Amin AN
- University of California Irvine, Irvine, CA 92697 USA
| | - Erin E. Cook
- Analysis Group, Inc., 111 Huntington Ave, 14th Floor, Boston, MA 02199 USA
| | - Fan Mu
- Analysis Group, Inc., 111 Huntington Ave, 14th Floor, Boston, MA 02199 USA
| | - Jingyi Chen
- Analysis Group, Inc., 111 Huntington Ave, 14th Floor, Boston, MA 02199 USA
| | - Pooja Desai
- AstraZeneca, US Medical Affairs, 1800 Concord Pike, Wilmington, DE 19850 USA
| | - Yemmie Oluwatosin
- AstraZeneca, US Medical Affairs, 1800 Concord Pike, Wilmington, DE 19850 USA
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9
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Johnston JG, Welch AK, Cain BD, Sayeski PP, Gumz ML, Wingo CS. Aldosterone: Renal Action and Physiological Effects. Compr Physiol 2023; 13:4409-4491. [PMID: 36994769 DOI: 10.1002/cphy.c190043] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
Aldosterone exerts profound effects on renal and cardiovascular physiology. In the kidney, aldosterone acts to preserve electrolyte and acid-base balance in response to changes in dietary sodium (Na+ ) or potassium (K+ ) intake. These physiological actions, principally through activation of mineralocorticoid receptors (MRs), have important effects particularly in patients with renal and cardiovascular disease as demonstrated by multiple clinical trials. Multiple factors, be they genetic, humoral, dietary, or otherwise, can play a role in influencing the rate of aldosterone synthesis and secretion from the adrenal cortex. Normally, aldosterone secretion and action respond to dietary Na+ intake. In the kidney, the distal nephron and collecting duct are the main targets of aldosterone and MR action, which stimulates Na+ absorption in part via the epithelial Na+ channel (ENaC), the principal channel responsible for the fine-tuning of Na+ balance. Our understanding of the regulatory factors that allow aldosterone, via multiple signaling pathways, to function properly clearly implicates this hormone as central to many pathophysiological effects that become dysfunctional in disease states. Numerous pathologies that affect blood pressure (BP), electrolyte balance, and overall cardiovascular health are due to abnormal secretion of aldosterone, mutations in MR, ENaC, or effectors and modulators of their action. Study of the mechanisms of these pathologies has allowed researchers and clinicians to create novel dietary and pharmacological targets to improve human health. This article covers the regulation of aldosterone synthesis and secretion, receptors, effector molecules, and signaling pathways that modulate its action in the kidney. We also consider the role of aldosterone in disease and the benefit of mineralocorticoid antagonists. © 2023 American Physiological Society. Compr Physiol 13:4409-4491, 2023.
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Affiliation(s)
- Jermaine G Johnston
- Division of Nephrology, Hypertension and Renal Transplantation, Department of Medicine, University of Florida, Gainesville, Florida, USA
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida, USA
- Nephrology Section, Veteran Administration Medical Center, North Florida/South Georgia Malcom Randall Department of Veterans Affairs Medical Center, Gainesville, Florida, USA
| | - Amanda K Welch
- Division of Nephrology, Hypertension and Renal Transplantation, Department of Medicine, University of Florida, Gainesville, Florida, USA
- Nephrology Section, Veteran Administration Medical Center, North Florida/South Georgia Malcom Randall Department of Veterans Affairs Medical Center, Gainesville, Florida, USA
| | - Brian D Cain
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida, USA
| | - Peter P Sayeski
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida, USA
| | - Michelle L Gumz
- Division of Nephrology, Hypertension and Renal Transplantation, Department of Medicine, University of Florida, Gainesville, Florida, USA
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida, USA
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida, USA
- Nephrology Section, Veteran Administration Medical Center, North Florida/South Georgia Malcom Randall Department of Veterans Affairs Medical Center, Gainesville, Florida, USA
| | - Charles S Wingo
- Division of Nephrology, Hypertension and Renal Transplantation, Department of Medicine, University of Florida, Gainesville, Florida, USA
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida, USA
- Nephrology Section, Veteran Administration Medical Center, North Florida/South Georgia Malcom Randall Department of Veterans Affairs Medical Center, Gainesville, Florida, USA
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10
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Yu C, Deng XJ, Xu D. Gene mutations in comorbidity of epilepsy and arrhythmia. J Neurol 2023; 270:1229-1248. [PMID: 36376730 DOI: 10.1007/s00415-022-11430-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 10/14/2022] [Accepted: 10/15/2022] [Indexed: 11/16/2022]
Abstract
Epilepsy is one of the most common neurological disorders, and sudden unexpected death in epilepsy (SUDEP) is the most severe outcome of refractory epilepsy. Arrhythmia is one of the heterogeneous factors in the pathophysiological mechanism of SUDEP with a high incidence in patients with refractory epilepsy, increasing the risk of premature death. The gene co-expressed in the brain and heart is supposed to be the genetic basis between epilepsy and arrhythmia, among which the gene encoding ion channel contributes to the prevalence of "cardiocerebral channelopathy" theory. Nevertheless, this theory could only explain the molecular mechanism of comorbid arrhythmia in part of patients with epilepsy (PWE). Therefore, we summarized the mutant genes that can induce comorbidity of epilepsy and arrhythmia and the possible corresponding treatments. These variants involved the genes encoding sodium, potassium, calcium and HCN channels, as well as some non-ion channel coding genes such as CHD4, PKP2, FHF1, GNB5, and mitochondrial genes. The relationship between genotype and clinical phenotype was not simple linear. Indeed, genes co-expressed in the brain and heart could independently induce epilepsy and/or arrhythmia. Mutant genes in brain could affect cardiac rhythm through central or peripheral regulation, while in the heart it could also affect cerebral electrical activity by changing the hemodynamics or internal environment. Analysis of mutations in comorbidity of epilepsy and arrhythmia could refine and expand the theory of "cardiocerebral channelopathy" and provide new insights for risk stratification of premature death and corresponding precision therapy in PWE.
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Affiliation(s)
- Cheng Yu
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan, 430022, Hubei Province, China
| | - Xue-Jun Deng
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan, 430022, Hubei Province, China
| | - Da Xu
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan, 430022, Hubei Province, China.
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11
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Higgins JA, Ramos DS, Gili S, Spetea C, Kanoski S, Ha D, McDonough AA, Youn JH. Stable potassium isotopes (41K/39K) track transcellular and paracellular potassium transport in biological systems. Front Physiol 2022; 13:1016242. [PMID: 36388124 PMCID: PMC9644202 DOI: 10.3389/fphys.2022.1016242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 09/21/2022] [Indexed: 12/04/2022] Open
Abstract
As the most abundant cation in archaeal, bacterial, and eukaryotic cells, potassium (K+) is an essential element for life. While much is known about the machinery of transcellular and paracellular K transport–channels, pumps, co-transporters, and tight-junction proteins—many quantitative aspects of K homeostasis in biological systems remain poorly constrained. Here we present measurements of the stable isotope ratios of potassium (41K/39K) in three biological systems (algae, fish, and mammals). When considered in the context of our current understanding of plausible mechanisms of K isotope fractionation and K+ transport in these biological systems, our results provide evidence that the fractionation of K isotopes depends on transport pathway and transmembrane transport machinery. Specifically, we find that passive transport of K+ down its electrochemical potential through channels and pores in tight-junctions at favors 39K, a result which we attribute to a kinetic isotope effect associated with dehydration and/or size selectivity at the channel/pore entrance. In contrast, we find that transport of K+ against its electrochemical gradient via pumps and co-transporters is associated with less/no isotopic fractionation, a result that we attribute to small equilibrium isotope effects that are expressed in pumps/co-transporters due to their slower turnover rate and the relatively long residence time of K+ in the ion pocket. These results indicate that stable K isotopes may be able to provide quantitative constraints on transporter-specific K+ fluxes (e.g., the fraction of K efflux from a tissue by channels vs. co-transporters) and how these fluxes change in different physiological states. In addition, precise determination of K isotope effects associated with K+ transport via channels, pumps, and co-transporters may provide unique constraints on the mechanisms of K transport that could be tested with steered molecular dynamic simulations.
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Affiliation(s)
- John A. Higgins
- Department of Geosciences, Princeton University, Princeton, NJ, United States
- *Correspondence: John A. Higgins,
| | - Danielle Santiago Ramos
- Department of Marine and Coastal Science, Rutgers University, New Brunswick, NJ, United States
| | - Stefania Gili
- Department of Geosciences, Princeton University, Princeton, NJ, United States
| | - Cornelia Spetea
- Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden
- Department of Molecular Biology, Princeton University, Princeton, NJ, United States
| | - Scott Kanoski
- Department of Human and Evolutionary Biology, University of Southern California, Los Angeles, CA, United States
| | - Darren Ha
- Department of Physiology and Neuroscience, University of Southern California Keck School of Medicine, Los Angeles, CA, United States
| | - Alicia A. McDonough
- Department of Physiology and Neuroscience, University of Southern California Keck School of Medicine, Los Angeles, CA, United States
| | - Jang H. Youn
- Department of Physiology and Neuroscience, University of Southern California Keck School of Medicine, Los Angeles, CA, United States
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12
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Youn JH, Oh YT, Gili S, McDonough AA, Higgins J. Estimating in vivo potassium distribution and fluxes with stable potassium isotopes. Am J Physiol Cell Physiol 2022; 322:C410-C420. [PMID: 35080924 PMCID: PMC8917925 DOI: 10.1152/ajpcell.00351.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Extracellular potassium (K+) homeostasis is achieved by a concerted effort of multiple organs and tissues. A limitation in studies of K+ homeostasis is inadequate techniques to quantify K+ fluxes into and out of organs and tissues in vivo. The goal of the present study was to test the feasibility of a novel approach to estimate K+ distribution and fluxes in vivo using stable K+ isotopes. 41K was infused as KCl into rats consuming control or K+-deficient chow (n = 4 each), 41K-to-39K ratios in plasma and red blood cells (RBCs) were measured by inductively coupled plasma mass spectrometry, and results were subjected to compartmental modeling. The plasma 41K/39K increased during 41K infusion and decreased upon infusion cessation, without altering plasma total K+ concentration ([K+], i.e., 41K + 39K). The time course of changes was analyzed with a two-compartmental model of K+ distribution and elimination. Model parameters, representing transport into and out of the intracellular pool and renal excretion, were identified in each rat, accurately predicting decreased renal K+ excretion in rats fed K+-deficient vs. control diet (P < 0.05). To estimate rate constants of K+ transport into and out of RBCs, 41K/39K were subjected to a simple model, indicating no effects of the K+-deficient diet. The findings support the feasibility of the novel stable isotope approach to quantify K+ fluxes in vivo and sets a foundation for experimental protocols using more complex models to identify heterogeneous intracellular K+ pools and to answer questions pertaining to K+ homeostatic mechanisms in vivo.
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Affiliation(s)
- Jang H. Youn
- 1Department of Physiology and Neuroscience, University of Southern California Keck School of Medicine, Los Angeles, California
| | - Young Taek Oh
- 1Department of Physiology and Neuroscience, University of Southern California Keck School of Medicine, Los Angeles, California
| | - Stefania Gili
- 2Department of Geosciences, Princeton University, Princeton, New Jersey
| | - Alicia A. McDonough
- 1Department of Physiology and Neuroscience, University of Southern California Keck School of Medicine, Los Angeles, California
| | - John Higgins
- 2Department of Geosciences, Princeton University, Princeton, New Jersey
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13
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Hager NA, McAtee CK, Lesko MA, O’Donnell AF. Inwardly Rectifying Potassium Channel Kir2.1 and its "Kir-ious" Regulation by Protein Trafficking and Roles in Development and Disease. Front Cell Dev Biol 2022; 9:796136. [PMID: 35223865 PMCID: PMC8864065 DOI: 10.3389/fcell.2021.796136] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Accepted: 12/15/2021] [Indexed: 11/13/2022] Open
Abstract
Potassium (K+) homeostasis is tightly regulated for optimal cell and organismal health. Failure to control potassium balance results in disease, including cardiac arrythmias and developmental disorders. A family of inwardly rectifying potassium (Kir) channels helps cells maintain K+ levels. Encoded by KCNJ genes, Kir channels are comprised of a tetramer of Kir subunits, each of which contains two-transmembrane domains. The assembled Kir channel generates an ion selectivity filter for K+ at the monomer interface, which allows for K+ transit. Kir channels are found in many cell types and influence K+ homeostasis across the organism, impacting muscle, nerve and immune function. Kir2.1 is one of the best studied family members with well-defined roles in regulating heart rhythm, muscle contraction and bone development. Due to their expansive roles, it is not surprising that Kir mutations lead to disease, including cardiomyopathies, and neurological and metabolic disorders. Kir malfunction is linked to developmental defects, including underdeveloped skeletal systems and cerebellar abnormalities. Mutations in Kir2.1 cause the periodic paralysis, cardiac arrythmia, and developmental deficits associated with Andersen-Tawil Syndrome. Here we review the roles of Kir family member Kir2.1 in maintaining K+ balance with a specific focus on our understanding of Kir2.1 channel trafficking and emerging roles in development and disease. We provide a synopsis of the vital work focused on understanding the trafficking of Kir2.1 and its role in development.
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Affiliation(s)
| | | | | | - Allyson F. O’Donnell
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, United States
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14
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Svendsen SL, Kornvig S, Berg P, Jensen IS, Araujo IBBA, Larsen CK, Leipziger J, Sørensen MV. Dietary K + acts as a genuine diuretic. Acta Physiol (Oxf) 2022; 234:e13762. [PMID: 34984847 DOI: 10.1111/apha.13762] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 11/29/2021] [Accepted: 01/01/2022] [Indexed: 12/11/2022]
Abstract
K+ balance in mammals relies on regulated renal K+ excretion matching unregulated fluctuating K+ intake. Upon a K+ rich meal, rapid and powerful K+ excretion is needed. Renal K+ secretion is stimulated by the increased tubular flow. We speculated that high K+ intake acutely increases urinary flow to stimulate K+ excretion. METHODS Mice were K+ challenged through diets or gavage. Post K+ loading urinary output, osmolarity, [K+ ]u , [Na+ ]u , plasma osmolarity, [copeptin]p , [K+ ]p , and [Na+ ]p were measured. To locate the mechanism of K+ -induced diuresis in the glomerular/tubular system we measured creatinine excretion and assessed functional transport in isolated perfused TALs and CDs during an acute [K+ ]bl switch from 3.6 to 6.5 mM. Molecular adaptations of transport proteins involved in water reabsorption were investigated by immunoblotting. RESULTS (1) Mice switched from a 1% to 2% K+ diet increased diuresis within 12 hours and reciprocally reduced diuresis when switched from 1% to 0.01% K+ diet. (2) A single K+ gavage load, corresponding to 25%-50% of daily K+ intake, induced 100% increase in diuresis within 30 minutes. This occurred despite augmented plasma osmolarity and AVP synthesis. (3) K+ gavage did not change GFR. (4) In isolated perfused TALs, shifting [K+ ]bl from 3.6 to 6.5 mM did not affect AVP-induced NaCl transport. (5) In sharp contrast, in isolated perfused CDs, shifting [K+ ]bl from 3.6 to 6.5 mM markedly reduced CD AVP sensitivity, ie inhibited water absorption. CONCLUSION Dietary K+ loading induces a rapidly on-setting diuresis. The mechanism of K+ -induced diuresis involves desensitization of the CD to AVP.
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Affiliation(s)
- Samuel L. Svendsen
- Department of Biomedicine, Physiology, Health Aarhus University Aarhus C Denmark
| | - Simon Kornvig
- Department of Biomedicine, Physiology, Health Aarhus University Aarhus C Denmark
| | - Peder Berg
- Department of Biomedicine, Physiology, Health Aarhus University Aarhus C Denmark
| | - Iben S. Jensen
- Department of Biomedicine, Physiology, Health Aarhus University Aarhus C Denmark
| | | | - Casper K. Larsen
- Department of Biomedicine, Physiology, Health Aarhus University Aarhus C Denmark
| | - Jens Leipziger
- Department of Biomedicine, Physiology, Health Aarhus University Aarhus C Denmark
| | - Mads V. Sørensen
- Department of Biomedicine, Physiology, Health Aarhus University Aarhus C Denmark
- Aarhus Institute for Advanced Studies (AIAS) Aarhus University Aarhus C Denmark
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15
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Evolving concepts of TRPV4 in controlling flow-sensitivity of the renal nephron. CURRENT TOPICS IN MEMBRANES 2022; 89:75-94. [DOI: 10.1016/bs.ctm.2022.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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16
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Bennet D, Khorsandian Y, Pelusi J, Mirabella A, Pirrotte P, Zenhausern F. Molecular and physical technologies for monitoring fluid and electrolyte imbalance: A focus on cancer population. Clin Transl Med 2021; 11:e461. [PMID: 34185420 PMCID: PMC8214861 DOI: 10.1002/ctm2.461] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 05/11/2021] [Accepted: 05/29/2021] [Indexed: 12/23/2022] Open
Abstract
Several clinical examinations have shown the essential impact of monitoring (de)hydration (fluid and electrolyte imbalance) in cancer patients. There are multiple risk factors associated with (de)hydration, including aging, excessive or lack of fluid consumption in sports, alcohol consumption, hot weather, diabetes insipidus, vomiting, diarrhea, cancer, radiation, chemotherapy, and use of diuretics. Fluid and electrolyte imbalance mainly involves alterations in the levels of sodium, potassium, calcium, and magnesium in extracellular fluids. Hyponatremia is a common condition among individuals with cancer (62% of cases), along with hypokalemia (40%), hypophosphatemia (32%), hypomagnesemia (17%), hypocalcemia (12%), and hypernatremia (1-5%). Lack of hydration and monitoring of hydration status can lead to severe complications, such as nausea/vomiting, diarrhea, fatigue, seizures, cell swelling or shrinking, kidney failure, shock, coma, and even death. This article aims to review the current (de)hydration (fluid and electrolyte imbalance) monitoring technologies focusing on cancer. First, we discuss the physiological and pathophysiological implications of fluid and electrolyte imbalance in cancer patients. Second, we explore the different molecular and physical monitoring methods used to measure fluid and electrolyte imbalance and the measurement challenges in diverse populations. Hydration status is assessed in various indices; plasma, sweat, tear, saliva, urine, body mass, interstitial fluid, and skin-integration techniques have been extensively investigated. No unified (de)hydration (fluid and electrolyte imbalance) monitoring technology exists for different populations (including sports, elderly, children, and cancer). Establishing novel methods and technologies to facilitate and unify measurements of hydration status represents an excellent opportunity to develop impactful new approaches for patient care.
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Affiliation(s)
- Devasier Bennet
- Center for Applied NanoBioscience and MedicineThe University of ArizonaCollege of MedicinePhoenixUSA
| | - Yasaman Khorsandian
- Center for Applied NanoBioscience and MedicineThe University of ArizonaCollege of MedicinePhoenixUSA
| | | | | | - Patrick Pirrotte
- Collaborative Center for Translational Mass SpectrometryTranslational Genomics Research InstitutePhoenixUSA
| | - Frederic Zenhausern
- Center for Applied NanoBioscience and MedicineThe University of ArizonaCollege of MedicinePhoenixUSA
- HonorHealth Research InstituteScottsdaleUSA
- Collaborative Center for Translational Mass SpectrometryTranslational Genomics Research InstitutePhoenixUSA
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17
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The struggle to equilibrate outer and inner milieus: Renal evolution revisited. Ann Anat 2020; 233:151610. [PMID: 33065247 DOI: 10.1016/j.aanat.2020.151610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 09/14/2020] [Accepted: 09/15/2020] [Indexed: 11/20/2022]
Abstract
The journey of life, from primordial protoplasm to a complex vertebrate form, is a tale of survival against incessant alterations in climate, surface topography, food chain, and chemistry of the external environment. Kidneys present with an ensemble embodiment of the adaptations devised by diverse life-forms to cope with such challenges and maintain a chemical equilibrium of water and solutes, both in and outside the body. This minireview revisits renal evolution utilizing the classic: From Fish to Philosopher; the story of our internal environment, by Prof. Homer W. Smith (1895-1962) as a template. Prof. Smith's views exemplified the invention of glomeruli, or its abolishment, as a mechanism to filter water. Moreover, with the need to preserve water, as in reptiles, the loop of Henle was introduced to concentrate urine. When compared to smaller mammals, the larger ones, albeit having loops of Henle of similar lengths, demonstrated a distinct packing of the nephrons in kidneys. Moreover, the renal portal system degenerated in mammals, while still present in other vertebrates. This account will present with a critique of the current concepts of renal evolution while examining how various other factors, including the ones that we know more about now, such as genetic factors, synchronize to achieve renal development. Finally, it will try to assess the validity of ideas laid by Prof. Smith with the knowledge that we possess now, and understand the complex architecture that evolution has imprinted on the kidneys during its struggle to survive over epochs.
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18
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McFarlin BE, Chen Y, Priver TS, Ralph DL, Mercado A, Gamba G, Madhur MS, McDonough AA. Coordinate adaptations of skeletal muscle and kidney to maintain extracellular [K +] during K +-deficient diet. Am J Physiol Cell Physiol 2020; 319:C757-C770. [PMID: 32845718 PMCID: PMC7654654 DOI: 10.1152/ajpcell.00362.2020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 08/17/2020] [Accepted: 08/19/2020] [Indexed: 12/16/2022]
Abstract
Extracellular fluid (ECF) potassium concentration ([K+]) is maintained by adaptations of kidney and skeletal muscle, responses heretofore studied separately. We aimed to determine how these organ systems work in concert to preserve ECF [K+] in male C57BL/6J mice fed a K+-deficient diet (0K) versus 1% K+ diet (1K) for 10 days (n = 5-6/group). During 0K feeding, plasma [K+] fell from 4.5 to 2 mM; hindlimb muscle (gastrocnemius and soleus) lost 28 mM K+ (from 115 ± 2 to 87 ± 2 mM) and gained 27 mM Na+ (from 27 ± 0.4 to 54 ± 2 mM). Doubling of muscle tissue [Na+] was not associated with inflammation, cytokine production or hypertension as reported by others. Muscle transporter adaptations in 0K- versus 1K-fed mice, assessed by immunoblot, included decreased sodium pump α2-β2 subunits, decreased K+-Cl- cotransporter isoform 3, and increased phosphorylated (p) Na+,K+,2Cl- cotransporter isoform 1 (NKCC1p), Ste20/SPS-1-related proline-alanine rich kinase (SPAKp), and oxidative stress-responsive kinase 1 (OSR1p) consistent with intracellular fluid (ICF) K+ loss and Na+ gain. Renal transporters' adaptations, effecting a 98% reduction in K+ excretion, included two- to threefold increased phosphorylated Na+-Cl- cotransporter (NCCp), SPAKp, and OSR1p abundance, limiting Na+ delivery to epithelial Na+ channels where Na+ reabsorption drives K+ secretion; and renal K sensor Kir 4.1 abundance fell 25%. Mass balance estimations indicate that over 10 days of 0K feeding, mice lose ~48 μmol K+ into the urine and muscle shifts ~47 μmol K+ from ICF to ECF, illustrating the importance of the concerted responses during K+ deficiency.
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Affiliation(s)
- Brandon E McFarlin
- Department of Physiology and Neuroscience, Keck School of Medicine of the University of Southern California, Los Angeles, California
| | - Yuhan Chen
- Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee
- Department of Cardiology, Nanjing University Medical School, Nanjing, China
| | - Taylor S Priver
- Department of Physiology and Neuroscience, Keck School of Medicine of the University of Southern California, Los Angeles, California
| | - Donna L Ralph
- Department of Physiology and Neuroscience, Keck School of Medicine of the University of Southern California, Los Angeles, California
| | - Adriana Mercado
- Department of Nephrology, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico
| | - Gerardo Gamba
- Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México and Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Meena S Madhur
- Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Alicia A McDonough
- Department of Physiology and Neuroscience, Keck School of Medicine of the University of Southern California, Los Angeles, California
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19
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Mu F, Betts KA, Woolley JM, Dua A, Wang Y, Zhong J, Wu EQ. Prevalence and economic burden of hyperkalemia in the United States Medicare population. Curr Med Res Opin 2020; 36:1333-1341. [PMID: 32459116 DOI: 10.1080/03007995.2020.1775072] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Objective: To estimate the prevalence and economic burden of hyperkalemia in the United States (US) Medicare population.Methods: Patients were selected from a 5% random sample of Medicare beneficiaries (01 January 2010-31 December 2014) to estimate the prevalence and economic burden of hyperkalemia. The prevalence for each calendar year was calculated as the number of patients with hyperkalemia divided by the total number of eligible patients per year. To estimate the economic burden of hyperkalemia, patients with hyperkalemia (cases) were matched 1:1 to patients without hyperkalemia (controls) on age group, chronic kidney disease [CKD] stage, dialysis treatment, and heart failure. The incremental 30-day and 1-year resource utilization and costs (2016 USD) associated with hyperkalemia were estimated.Results: The estimated prevalence of hyperkalemia was 2.6-2.7% in the overall population and 8.9-9.3% among patients with CKD and/or heart failure. Patients with hyperkalemia had higher 1-year rates of inpatient admissions (1.28 vs. 0.44), outpatient visits (30.48 vs. 23.88), emergency department visits (2.01 vs. 1.17), and skilled nursing facility admissions (0.36 vs. 0.11) than the matched controls (all p < .001). Patients with hyperkalemia incurred on average $7208 higher 30-day costs ($8894 vs. $1685) and $19,348 higher 1-year costs ($34,362 vs. $15,013) than controls (both p < .001). Among patients with CKD and/or heart failure, the 30-day and 1-year total cost differences between cohorts were $7726 ($9906 vs. $2180) and $21,577 ($41,416 vs. $19,839), respectively (both p < .001).Conclusions: Hyperkalemia had an estimated prevalence of 2.6-2.7% in the Medicare population and was associated with markedly high healthcare costs.
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Affiliation(s)
- Fan Mu
- Analysis Group, Inc, Boston, MA, USA
| | | | | | | | - Yao Wang
- Analysis Group, Inc, Boston, MA, USA
| | - Jia Zhong
- Analysis Group, Inc, Boston, MA, USA
| | - Eric Q Wu
- Analysis Group, Inc, Boston, MA, USA
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20
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Zhang F, Bian J, Chen X, Huang J, Smith N, Lu W, Xu Y, Lee J, Wu X. Roles for intracellular cation transporters in respiratory growth of yeast. Metallomics 2020; 11:1667-1678. [PMID: 31402362 DOI: 10.1039/c9mt00145j] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Potassium is involved in copper and iron metabolism in eukaryotic Golgi apparatus, but it is not clear yet whether potassium distributions in other vesicles also affect copper and iron metabolism. Here we show that respiratory growth and iron acquisition by the yeast Saccharomyces cerevisiae relies on potassium (K+) compartmentalization to the mitochondria, as well as the vacuole and late endosome via K+/H+ exchangers Mdm38p, Vnx1p and Nhx1p, respectively. The data indicate that NHX1 and VNX1 knock-out cells grow better than wild type cells on non-fermentable YPEG media, while MDM38 knock-out cells display a growth defect on YPEG media. The over expression of the KHA1 gene located on the Golgi apparatus partially compensates for the growth defect of the MDM38 knock-out strain. The results suggest that the vacuole and late endosome are important potassium storage vesicles and Mdm38p affects the mitochondrial function by regulating copper and iron metabolism. Our study reveals potassium compartmentalization to the subcellular vesicles is relevant for respiratory growth by improving copper utilization and promoting iron absorption.
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Affiliation(s)
- Feng Zhang
- College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China.
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21
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Lake JA, Brannick EM, Papah MB, Lousenberg C, Velleman SG, Abasht B. Blood Gas Disturbances and Disproportionate Body Weight Distribution in Broilers With Wooden Breast. Front Physiol 2020; 11:304. [PMID: 32317988 PMCID: PMC7154160 DOI: 10.3389/fphys.2020.00304] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 03/19/2020] [Indexed: 12/13/2022] Open
Abstract
Wooden breast syndrome is a widespread and economically important myopathy and vasculopathy of fast growing, commercial broiler chickens, primarily affecting birds with high feed efficiency and large breast muscle yield. To investigate potential systemic physiological differences between birds affected and unaffected by wooden breast, a total of 103 market-age Cobb 500 broilers were sampled for 13 blood parameters and the relative weights of the pectoralis major muscle, pectoralis minor muscle, external oblique muscle, wing, heart, lungs, liver, and spleen. Blood analysis was performed on samples taken from the brachial vein of live birds and revealed significant differences in venous blood gases between affected and unaffected chickens. Chickens with wooden breast exhibited significantly higher potassium (K+) and lower partial pressure of oxygen (pO2), oxygen saturation (sO2), and pH. Additionally, affected males had significantly higher partial pressure of carbon dioxide (pCO2) and total carbon dioxide (TCO2) than unaffected males. Wooden breast affected broilers also possessed a significantly heavier pectoralis major muscle and whole feathered wing compared to unaffected broilers. Blood gas disturbances characterized by high pCO2 and low pH are indicative of insufficient respiratory gas exchange, suggesting that wooden breast affected broilers have an elevated metabolic rate that may also be inadequately compensated due to cardiovascular deficiencies such as poor venous return or respiratory insufficiency. Lung tissues from 12 birds with extreme sO2 values were subsequently examined to assess whether lung pathology contributed to the observed blood gas disturbance. Comparison of lung morphology between affected and unaffected birds revealed no apparent differences that could contribute to decreased parabronchial gas exchange. However, an interesting finding was the detection of pulmonary phlebitis in one of the wooden breast-affected samples consistent with vascular changes observed in pectoralis major muscle exhibiting the wooden breast phenotype. Our results suggest that the effects of wooden breast are not limited to the pectoralis major muscle and further indicate the importance of research into metabolic changes associated with the myopathy.
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Affiliation(s)
- Juniper A Lake
- Center for Bioinformatics and Computational Biology, University of Delaware, Newark, DE, United States.,Department of Animal and Food Sciences, University of Delaware, Newark, DE, United States
| | - Erin M Brannick
- Department of Animal and Food Sciences, University of Delaware, Newark, DE, United States
| | - Michael B Papah
- Department of Animal and Food Sciences, University of Delaware, Newark, DE, United States
| | - Cory Lousenberg
- Department of Animal and Food Sciences, University of Delaware, Newark, DE, United States
| | - Sandra G Velleman
- Department of Animal Sciences, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, OH, United States
| | - Behnam Abasht
- Center for Bioinformatics and Computational Biology, University of Delaware, Newark, DE, United States.,Department of Animal and Food Sciences, University of Delaware, Newark, DE, United States
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22
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Menni C, McCallum L, Pietzner M, Zierer J, Aman A, Suhre K, Mohney RP, Mangino M, Friedrich N, Spector TD, Padmanabhan S. Metabolomic profiling identifies novel associations with Electrolyte and Acid-Base Homeostatic patterns. Sci Rep 2019; 9:15088. [PMID: 31636301 PMCID: PMC6803625 DOI: 10.1038/s41598-019-51492-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 10/01/2019] [Indexed: 12/17/2022] Open
Abstract
Electrolytes have a crucial role in maintaining health and their serum levels are homeostatically maintained within a narrow range by multiple pathways involving the kidneys. Here we use metabolomics profiling (592 fasting serum metabolites) to identify molecular markers and pathways associated with serum electrolyte levels in two independent population-based cohorts. We included 1523 adults from TwinsUK not on blood pressure-lowering therapy and without renal impairment to look for metabolites associated with chloride, sodium, potassium and bicarbonate by running linear mixed models adjusting for covariates and multiple comparisons. For each electrolyte, we further performed pathway enrichment analysis (PAGE algorithm). Results were replicated in an independent cohort. Chloride, potassium, bicarbonate and sodium associated with 10, 58, 36 and 17 metabolites respectively (each P < 2.1 × 10-5), mainly lipids. Of all the electrolytes, serum potassium showed the most significant associations with individual fatty acid metabolites and specific enrichment of fatty acid pathways. In contrast, serum sodium and bicarbonate showed associations predominantly with amino-acid related species. In the first study to examine systematically associations between serum electrolytes and small circulating molecules, we identified novel metabolites and metabolic pathways associated with serum electrolyte levels. The role of these metabolic pathways on electrolyte homeostasis merits further studies.
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Affiliation(s)
- Cristina Menni
- Department of Twin Research & Genetic Epidemiology, King's College London, London, UK.
| | - Linsay McCallum
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Maik Pietzner
- Institute of Clinical Chemistry and Laboratory Medicine, University Medicine Greifswald, Greifswald, Germany
- DZHK (German Center for Cardiovascular Research), partner site Greifswald, Greifswald, Germany
| | - Jonas Zierer
- Department of Twin Research & Genetic Epidemiology, King's College London, London, UK
- Department of Physiology and Biophysics, Weill Cornell Medical College in Qatar, Education City, Qatar Foundation, Doha, Qatar
| | - Alisha Aman
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | | | | | - Massimo Mangino
- Department of Twin Research & Genetic Epidemiology, King's College London, London, UK
| | - Nele Friedrich
- Institute of Clinical Chemistry and Laboratory Medicine, University Medicine Greifswald, Greifswald, Germany
| | - Tim D Spector
- Department of Twin Research & Genetic Epidemiology, King's College London, London, UK
| | - Sandosh Padmanabhan
- Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK.
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23
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Ydegaard R, Svenningsen P, Bistrup C, Andersen RF, Stubbe J, Buhl KB, Marcussen N, Hinrichs GR, Iraqi H, Zamani R, Dimke H, Jensen BL. Nephrotic syndrome is associated with increased plasma K + concentration, intestinal K + losses, and attenuated urinary K + excretion: a study in rats and humans. Am J Physiol Renal Physiol 2019; 317:F1549-F1562. [PMID: 31566427 DOI: 10.1152/ajprenal.00179.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The present study tested the hypotheses that nephrotic syndrome (NS) leads to renal K+ loss because of augmented epithelial Na+ channel (ENaC) activity followed by downregulation of renal K+ secretory pathways by suppressed aldosterone. The hypotheses were addressed by determining K+ balance and kidney abundance of K+ and Na+ transporter proteins in puromycin aminonucleoside (PAN)-induced rat nephrosis. The effects of amiloride and angiotensin II type 1 receptor and mineralocorticoid receptor (MR) antagonists were tested. Glucocorticoid-dependent MR activation was tested by suppression of endogenous glucocorticoid with dexamethasone. Urine and plasma samples were obtained from pediatric patients with NS in acute and remission phases. PAN-induced nephrotic rats had ENaC-dependent Na+ retention and displayed lower renal K+ excretion but elevated intestinal K+ secretion that resulted in less cumulated K+ in NS. Aldosterone was suppressed at day 8. The NS-associated changes in intestinal, but not renal, K+ handling responded to suppression of corticosterone, whereas angiotensin II type 1 receptor and MR blockers and amiloride had no effect on urine K+ excretion during NS. In PAN-induced nephrosis, kidney protein abundance of the renal outer medullary K+ channel and γ-ENaC were unchanged, whereas the Na+-Cl- cotransporter was suppressed and Na+-K+-ATPase increased. Pediatric patients with acute NS displayed suppressed urine Na+-to-K+ ratios compared with remission and elevated plasma K+ concentration, whereas fractional K+ excretion did not differ. Acute NS is associated with less cumulated K+ in a rat model, whereas patients with acute NS have elevated plasma K+ and normal renal fractional K+ excretion. In NS rats, K+ balance is not coupled to ENaC activity but results from opposite changes in renal and fecal K+ excretion with a contribution from corticosteroid MR-driven colonic secretion.
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Affiliation(s)
- Rikke Ydegaard
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Per Svenningsen
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Claus Bistrup
- Department of Nephrology, Odense University Hospital, Odense, Denmark.,Department of Clinical Research, University of Southern Denmark, Odense, Denmark
| | | | - Jane Stubbe
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | | | - Niels Marcussen
- Department of Clinical Pathology, Odense University Hospital, Odense, Denmark
| | - Gitte Rye Hinrichs
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Hiba Iraqi
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Reza Zamani
- Department of Urology, Odense University Hospital, Odense, Denmark
| | - Henrik Dimke
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark.,Department of Nephrology, Odense University Hospital, Odense, Denmark
| | - Boye L Jensen
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
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24
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Bian J, Shi X, Li Q, Zhao M, Wang L, Lee J, Tao M, Wu X. A novel functional role of nickel in sperm motility and eukaryotic cell growth. J Trace Elem Med Biol 2019; 54:142-149. [PMID: 31109604 DOI: 10.1016/j.jtemb.2019.04.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 03/29/2019] [Accepted: 04/24/2019] [Indexed: 12/29/2022]
Abstract
BACKGROUND Metal ions are essential for numerous life processes. This study aims to investigate the relationship between seminal quality and ion levels in seminal plasma. BASIC PROCEDURES A total of 205 semen samples were collected and seminal plasma ion levels were examined with inductively-coupled plasma-mass spectrometry. The nickel function was demonstrated by in vitro assay and cell growth. MAIN FINDINGS The low sperm motility group showed distinctively reduced nickel concentration in seminal plasma compared with the normal sperm motility group. However, arsenic, sulfur, selenium, magnesium and zinc were negatively associated with sperm quality. No significant relationship between other examined cations and semen quality was observed. In vitro assay suggested low concentration of nickel significantly increased sperm total motility and progressive motility. Cell growth assay further confirmed nickel promoted eukaryotic yeast cell growth. Nickel level in seminal plasma may play important functions to determine sperm quality. PRINCIPAL CONCLUSIONS Our study reveals a strong correlation between S, Mg, Se, Zn, As, Ni and seminal quality as well as discovers a novel functional role of nickel in sperm motility and eukaryotic cell growth. These findings may provide a potential avenue for assessment of sperm quality and treatment of reproduction disorders.
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Affiliation(s)
- Jiang Bian
- College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China; Reproductive Medicine Center, Department of Obstetrics and Gynecology, Shanghai Jiaotong University Affiliated Sixth People's Hospital, 200233, Shanghai, China
| | - Xiaohong Shi
- Reproductive Medicine Center, Department of Obstetrics and Gynecology, Shanghai Jiaotong University Affiliated Sixth People's Hospital, 200233, Shanghai, China
| | - Qin Li
- College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Miaoyun Zhao
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska, 68588, USA
| | - Lingyun Wang
- College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China
| | - Jaekwon Lee
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska, 68588, USA
| | - Minfang Tao
- Reproductive Medicine Center, Department of Obstetrics and Gynecology, Shanghai Jiaotong University Affiliated Sixth People's Hospital, 200233, Shanghai, China.
| | - Xiaobin Wu
- College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China.
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25
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Kim H, Park S, Jhee JH, Yun HR, Park JT, Han SH, Lee J, Kim SW, Kim YH, Oh YK, Kang SW, Choi KH, Yoo TH. Urinary angiotensinogen level is associated with potassium homeostasis and clinical outcome in patients with polycystic kidney disease: a prospective cohort study. BMC Nephrol 2019; 20:104. [PMID: 30909873 PMCID: PMC6434770 DOI: 10.1186/s12882-019-1292-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Accepted: 03/11/2019] [Indexed: 01/13/2023] Open
Abstract
Background Guidelines for general hypertension treatment do not recommend the combined use of renin-angiotensin-aldosterone system (RAAS) inhibitors due to the risk of hyperkalemia. However, a recent clinical trial showed that polycystic kidney disease (PKD) patients had infrequent episodes of hyperkalemia despite receiving combined RAAS inhibitors. Because intrarenal RAAS is a main component for renal potassium handling, we further investigated the association between intrarenal RAAS activity and serum potassium level in patients with chronic kidney disease, particularly in PKD patients, and examined whether intrarenal RAAS activity has a prognostic role in patients with PKD. Methods A total of 1788 subjects from the KoreaN cohort study for Outcome in patients With Chronic Kidney Disease (KNOW-CKD) were enrolled in this study. Intrarenal RAAS activity was assessed by the measurement of urinary angiotensinogen (AGT). The primary outcome was the composite of all-cause mortality and renal function decline. Results Patients with PKD had a significantly lower serum potassium level in chronic kidney disease stages 1 to 3b than non-PKD patients. In logistic regression analysis, after adjusting for multiple confounders, PKD patients had a significantly lower risk of hyperkalemia than non-PKD patients. In multivariable linear regression analysis, the urinary AGT/creatinine (Cr) ratio was negatively correlated with the serum potassium level (β = − 0.058, P = 0.017) and positively correlated with the transtubular potassium gradient (TTKG, β = 0.087, P = 0.001). In propensity score matching analysis, after matching factors associated with serum potassium and TTKG, PKD patients had a significantly higher TTKG (P = 0.021) despite a lower serum potassium level (P = 0.004). Additionally, the urinary AGT/Cr ratio was significantly higher in PKD patients than in non-PKD patients (P = 0.011). In 293 patients with PKD, high urinary AGT/Cr ratio was associated with increased risk of the composite outcome (hazard ratio 1.29; 95% confidence interval, 1.07–1.55; P = 0.007). Conclusions High activity of intrarenal RAAS is associated with increased urinary potassium excretion and low serum potassium level in patients with PKD. In addition, intrarenal RAAS activity can be a prognostic marker for mortality and renal function decline in these patients.
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Affiliation(s)
- Hyoungnae Kim
- Department of Internal Medicine, College of Medicine, Institute of Kidney Disease Research, Yonsei University, Seoul, 03722, Republic of Korea.,Division of Nephrology, Soonchunhyang University Hospital, Seoul, Republic of Korea
| | - Seohyun Park
- Department of Internal Medicine, College of Medicine, Institute of Kidney Disease Research, Yonsei University, Seoul, 03722, Republic of Korea
| | - Jong Hyun Jhee
- Division of Nephrology and Hypertension, Department of Internal Medicine, Inha University College of Medicine, Incheon, Republic of Korea
| | - Hae-Ryong Yun
- Department of Internal Medicine, College of Medicine, Institute of Kidney Disease Research, Yonsei University, Seoul, 03722, Republic of Korea
| | - Jung Tak Park
- Department of Internal Medicine, College of Medicine, Institute of Kidney Disease Research, Yonsei University, Seoul, 03722, Republic of Korea
| | - Seung Hyeok Han
- Department of Internal Medicine, College of Medicine, Institute of Kidney Disease Research, Yonsei University, Seoul, 03722, Republic of Korea
| | - Joongyub Lee
- Medical Research Collaborating Center, Seoul National University Hospital and Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Soo Wan Kim
- Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Republic of Korea
| | - Yeong Hoon Kim
- Department of Internal Medicine, Busan Paik Hospital, Inje University, Busan, Republic of Korea
| | - Yun Kyu Oh
- Department of Internal Medicine, Seoul National University College of Medicine, Boramae Medical Center, Seoul, Republic of Korea
| | - Shin-Wook Kang
- Department of Internal Medicine, College of Medicine, Institute of Kidney Disease Research, Yonsei University, Seoul, 03722, Republic of Korea
| | - Kyu Hun Choi
- Department of Internal Medicine, College of Medicine, Institute of Kidney Disease Research, Yonsei University, Seoul, 03722, Republic of Korea
| | - Tae-Hyun Yoo
- Department of Internal Medicine, College of Medicine, Institute of Kidney Disease Research, Yonsei University, Seoul, 03722, Republic of Korea.
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26
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Tomilin V, Mamenko M, Zaika O, Wingo CS, Pochynyuk O. TRPV4 deletion protects against hypokalemia during systemic K + deficiency. Am J Physiol Renal Physiol 2019; 316:F948-F956. [PMID: 30838874 DOI: 10.1152/ajprenal.00043.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Tight regulation of K+ balance is fundamental for normal physiology. Reduced dietary K+ intake, which is common in Western diets, often leads to hypokalemia and associated cardiovascular- and kidney-related pathologies. The distal nephron, and, specifically, the collecting duct (CD), is the major site of controlled K+ reabsorption via H+-K+-ATPase in the state of dietary K+ deficiency. We (Mamenko MV, Boukelmoune N, Tomilin VN, Zaika OL, Jensen VB, O'Neil RG, Pochynyuk OM. Kidney Int 91: 1398-1409, 2017) have previously demonstrated that the transient receptor potential vanilloid type 4 (TRPV4) Ca2+ channel, abundantly expressed in the CD, contributes to renal K+ handling by promoting flow-induced K+ secretion. Here, we investigated a potential role of TRPV4 in controlling H+-K+-ATPase-dependent K+ reabsorption in the CD. Treatment with a K+-deficient diet (<0.01% K+) for 7 days reduced serum K+ levels in wild-type (WT) mice from 4.3 ± 0.2 to 3.3 ± 0.2 mM but not in TRPV4-/- mice (4.3 ± 0.1 and 4.2 ± 0.3 mM, respectively). Furthermore, we detected a significant reduction in 24-h urinary K+ levels in TRPV4-/- compared with WT mice upon switching to K+-deficient diet. TRPV4-/- animals also had significantly more acidic urine on a low-K+ diet, but not on a regular (0.9% K+) or high-K+ (5% K+) diet, which is consistent with increased H+-K+-ATPase activity. Moreover, we detected a greatly accelerated H+-K+-ATPase-dependent intracellular pH extrusion in freshly isolated CDs from TRPV4-/- compared with WT mice fed a K+-deficient diet. Overall, our results demonstrate a novel kaliuretic role of TRPV4 by inhibiting H+-K+-ATPase-dependent K+ reabsorption in the CD. We propose that TRPV4 inhibition could be a novel strategy to manage certain hypokalemic states in clinical settings.
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Affiliation(s)
- Viktor Tomilin
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston , Houston, Texas
| | - Mykola Mamenko
- Department of Physiology, Medical College of Georgia, Augusta University , Augusta, Georgia
| | - Oleg Zaika
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston , Houston, Texas
| | - Charles S Wingo
- Division of Nephrology, Hypertension and Transplantation, Department of Medicine, University of Florida , Gainesville, Florida.,North Florida/South Georgia Veterans Health System, Gainesville, Florida
| | - Oleh Pochynyuk
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston , Houston, Texas
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27
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Blaženović I, Oh YT, Li F, Ji J, Nguyen AK, Wancewicz B, Bender JM, Fiehn O, Youn JH. Effects of Gut Bacteria Depletion and High-Na + and Low-K + Intake on Circulating Levels of Biogenic Amines. Mol Nutr Food Res 2018; 63:e1801184. [PMID: 30513547 DOI: 10.1002/mnfr.201801184] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 11/13/2018] [Indexed: 12/18/2022]
Abstract
SCOPE High-sodium and low-potassium (HNaLK) content in Western diets increases the risk of hypertension and cardiovascular disease (CVD). It is investigated if the dietary minerals interact with gut bacteria to modulate circulating levels of biogenic amines, which are implicated in various pathologies, including hypertension and CVD. METHODS AND RESULTS Using a metabolomic approach to target biogenic amines, the effects of gut bacteria depletion and HNaLK intake on circulating levels of biogenic amines in rats are examined. Forty-five metabolites whose plasma levels are significantly altered by gut bacteria depletion (p < 0.05) are found, indicating their regulation by gut bacteria. Many of them are not previously linked to gut bacteria; therefore, these data provide novel insights into physiological or pathological roles of gut bacteria. A number of plasma metabolites that are altered both by gut bacteria and HNaLK intake are also found, suggesting possible interactions of the diet and gut bacteria in the modulation of these metabolites. The diet effects are observed with significant changes in the gut bacterial taxa Porphyromonadaceae and Prevotellaceae (p < 0.05). CONCLUSION The dietary minerals may regulate abundances of certain gut bacteria to alter circulating levels of biogenic amines, which may be linked to host physiology or pathology.
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Affiliation(s)
- Ivana Blaženović
- West Coast Metabolomics Center, University of California Davis Genome Center, Davis, CA 95616, USA
| | - Young Taek Oh
- Department of Physiology and Neuroscience, Keck School of Medicine of USC, Los Angeles, CA 90089, USA
| | - Fan Li
- Single Cell, Sequencing, and CyTOF Core Lab, Children's Hospital Los Angeles, Los Angeles, CA 90027, USA
| | - Jian Ji
- West Coast Metabolomics Center, University of California Davis Genome Center, Davis, CA 95616, USA.,School of Food Science, State Key Laboratory of Food Science and Technology, National Engineering Research Center for Functional Foods, School of Food Science Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, Wuxi, Jiangsu, China
| | - Ahn-Khoi Nguyen
- Department of Exercise Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Benjamin Wancewicz
- West Coast Metabolomics Center, University of California Davis Genome Center, Davis, CA 95616, USA
| | - Jeffrey M Bender
- USC Keck School of Medicine and Children's Hospital Los Angeles, Los Angeles, CA 90027, USA
| | - Oliver Fiehn
- West Coast Metabolomics Center, University of California Davis Genome Center, Davis, CA 95616, USA.,Department of Biochemistry, Faculty of Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Jang H Youn
- Department of Physiology and Neuroscience, Keck School of Medicine of USC, Los Angeles, CA 90089, USA
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28
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Kamel KS, Schreiber M, Halperin ML. Renal potassium physiology: integration of the renal response to dietary potassium depletion. Kidney Int 2018; 93:41-53. [PMID: 29102372 DOI: 10.1016/j.kint.2017.08.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 07/31/2017] [Accepted: 08/03/2017] [Indexed: 01/30/2023]
Abstract
We summarize the current understanding of the physiology of the renal handling of potassium (K+), and present an integrative view of the renal response to K+ depletion caused by dietary K+ restriction. This renal response involves contributions from different nephron segments, and aims to diminish the rate of excretion of K+ as a result of: decreasing the rate of electrogenic (and increasing the rate of electroneutral) reabsorption of sodium in the aldosterone-sensitive distal nephron (ASDN), decreasing the abundance of renal outer medullary K+ channels in the luminal membrane of principal cells in the ASDN, decreasing the flow rate in the ASDN, and increasing the reabsorption of K+ in the cortical and medullary collecting ducts. The implications of this physiology for the association between K+ depletion and hypertension, and K+ depletion and formation of calcium kidney stones are discussed.
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Affiliation(s)
- Kamel S Kamel
- Renal Division, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada; Keenan Research Center, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada.
| | - Martin Schreiber
- Renal Division, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Mitchell L Halperin
- Renal Division, St. Michael's Hospital, University of Toronto, Toronto, Ontario, Canada; Keenan Research Center, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada
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29
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Long B, Warix JR, Koyfman A. Controversies in Management of Hyperkalemia. J Emerg Med 2018; 55:192-205. [DOI: 10.1016/j.jemermed.2018.04.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2017] [Revised: 02/07/2018] [Accepted: 04/10/2018] [Indexed: 12/24/2022]
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30
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West CA, Welling PA, West DA, Coleman RA, Cheng KY, Chen C, DuBose TD, Verlander JW, Baylis C, Gumz ML. Renal and colonic potassium transporters in the pregnant rat. Am J Physiol Renal Physiol 2018; 314:F251-F259. [PMID: 29046297 PMCID: PMC5866449 DOI: 10.1152/ajprenal.00288.2017] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 10/11/2017] [Accepted: 10/11/2017] [Indexed: 11/22/2022] Open
Abstract
Gestational potassium retention, most of which occurs during late pregnancy, is essential for fetal development. The purpose of this study was to examine mechanisms underlying changes in potassium handling by the kidney and colon in pregnancy. We found that potassium intake and renal excretion increased in late pregnancy while fecal potassium excretion remained unchanged and that pregnant rats exhibited net potassium retention. By quantitative PCR we found markedly increased H+-K+-ATPase type 2 (HKA2) mRNA expression in the cortex and outer medullary of late pregnant vs. virgin. Renal outer medullary potassium channel (ROMK) mRNA was unchanged in the cortex, but apical ROMK abundance (by immunofluorescence) was decreased in pregnant vs. virgin in the distal convoluted tubule (DCT) and connecting tubule (CNT). Big potassium-α (BKα) channel-α protein abundance in intercalated cells in the cortex and outer medullary collecting ducts (by immunohistochemistry) fell in late pregnancy. In the distal colon we found increased HKA2 mRNA and protein abundance (Western blot) and decreased BKα protein with no observed changes in mRNA. Therefore, the potassium retention of pregnancy is likely to be due to increased collecting duct potassium reabsorption (via increased HKA2), decreased potassium secretion (via decreased ROMK and BK), as well as increased colonic reabsorption via HKA2.
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Affiliation(s)
- Crystal A West
- Department of Medicine, Georgetown University, Washington, District of Columiba
| | - Paul A Welling
- Department of Physiology, University of Maryland School of Medicine , Baltimore, Maryland
| | - David A West
- Department of Medicine, Georgetown University, Washington, District of Columiba
| | - Richard A Coleman
- Department of Physiology, University of Maryland School of Medicine , Baltimore, Maryland
| | - Kit-Yan Cheng
- Department of Medicine, University of Florida , Gainesville, Florida
| | - Chao Chen
- Department of Medicine, University of Florida , Gainesville, Florida
| | - Thomas D DuBose
- Department of Medicine, Wake Forest School of Medicine , Winston-Salem, North Carolina
| | - Jill W Verlander
- Department of Medicine, University of Florida , Gainesville, Florida
| | - Chris Baylis
- Department of Medicine, University of Florida , Gainesville, Florida
- Department of Physiology and Functional Genomics, University of Florida , Gainesville, Florida
| | - Michelle L Gumz
- Department of Medicine, University of Florida , Gainesville, Florida
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31
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New Therapeutic Approaches for the Treatment of Hyperkalemia in Patients Treated with Renin-Angiotensin-Aldosterone System Inhibitors. Cardiovasc Drugs Ther 2018; 32:99-119. [DOI: 10.1007/s10557-017-6767-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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32
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Berg M, Plöntzke J, Leonhard-Marek S, Müller K, Röblitz S. A dynamic model to simulate potassium balance in dairy cows. J Dairy Sci 2017; 100:9799-9814. [DOI: 10.3168/jds.2016-12443] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 08/14/2017] [Indexed: 11/19/2022]
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33
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Trefz F, Lorenz I, Constable P. Effects of profound acidemia on the dynamic glucose and insulin response and plasma potassium and phosphorus concentrations during an intravenous glucose tolerance test in neonatal calves. J Dairy Sci 2017; 100:9163-9176. [DOI: 10.3168/jds.2017-12690] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Accepted: 07/21/2017] [Indexed: 12/12/2022]
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34
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Potassium regulation in the neonate. Pediatr Nephrol 2017; 32:2037-2049. [PMID: 28378030 DOI: 10.1007/s00467-017-3635-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2016] [Revised: 02/13/2017] [Accepted: 02/21/2017] [Indexed: 10/19/2022]
Abstract
Potassium, the major cation in intracelluar fluids, is essential for vital biological functions. Neonates maintain a net positive potassium balance, which is fundamental to ensure somatic growth but places these infants, especially those born prematurely, at risk for life-threatening disturbances in potassium concentration [K+] in the extracellular fluid compartment. Potassium conservation is achieved by maximizing gastrointestinal absorption and minimizing renal losses. A markedly low glomerular filtration rate, plus adaptations in tubular transport along the nephron, result in low potassium excretion in the urine of neonates. Careful evaluation of clinical data using reference values that are normal for the neonate's postmenstrual age is critical to avoid over-treating infants with laboratory results that represent physiologic values for their developmental stage. The treatment should be aimed at correcting the primary cause when possible. Alterations in the levels or sensitivity to aldosterone are common in neonates. In symptomatic patients, the disturbances in [K+] should be corrected promptly, with close electrocardiographic monitoring. Plasma [K+] should be monitored during the first 72 h of life in all premature infants born before 30 weeks of postmenstrual age as these infants are prone to develop non-oliguric hyperkalemia with potential serious complications.
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35
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Kraus D, Wanner C, Kraus BJ. A Janus-headed electrolyte and 'RALES' disease'. ESC Heart Fail 2017; 4:195-197. [PMID: 28772052 PMCID: PMC5542742 DOI: 10.1002/ehf2.12173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 05/08/2017] [Accepted: 05/16/2017] [Indexed: 11/06/2022] Open
Affiliation(s)
- Daniel Kraus
- Divisions of Nephrology and Cardiology, 1st Department of Medicine, Comprehensive Heart Failure Centre (CHFC), Würzburg University Hospital, Würzburg, Germany
| | - Christoph Wanner
- Divisions of Nephrology and Cardiology, 1st Department of Medicine, Comprehensive Heart Failure Centre (CHFC), Würzburg University Hospital, Würzburg, Germany
| | - Bettina J Kraus
- Divisions of Nephrology and Cardiology, 1st Department of Medicine, Comprehensive Heart Failure Centre (CHFC), Würzburg University Hospital, Würzburg, Germany
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36
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Bizzarri C, Pedicelli S, Cappa M, Cianfarani S. Water Balance and 'Salt Wasting' in the First Year of Life: The Role of Aldosterone-Signaling Defects. Horm Res Paediatr 2017; 86:143-153. [PMID: 27598420 DOI: 10.1159/000449057] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 08/10/2016] [Indexed: 11/19/2022] Open
Abstract
In newborns and infants, dehydration and salt wasting represent a relatively common cause of admission to hospital and may result in life-threatening complications. Kidneys are responsible for electrolyte homoeostasis, but neonatal kidneys show low glomerular filtration rate and immaturity of the distal nephron, leading to reduced ability to concentrate urine. High extrarenal fluid losses often contribute to the increased occurrence of electrolyte disorders. Aldosterone is essential for sodium retention in the kidney, salivary glands, sweat glands and colon. A partial and transient aldosterone resistance is present in newborns and infants, thus reducing the capability of maintaining sodium balance in specific pathological conditions. The present review examines the mechanisms making infants more susceptible to salt wasting. Peculiar aspects of renal physiology in the first year of life and management of electrolyte disorders (i.e. sodium and potassium) are considered. Finally, inherited disorders associated with neonatal salt wasting are examined in detail. © 2016 S. Karger AG, Basel.
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Affiliation(s)
- Carla Bizzarri
- Unit of Endocrinology and Diabetes, 'Bambino Gesù' Children's Hospital, Rome, Italy
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37
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McDonough AA, Veiras LC, Guevara CA, Ralph DL. Cardiovascular benefits associated with higher dietary K + vs. lower dietary Na +: evidence from population and mechanistic studies. Am J Physiol Endocrinol Metab 2017; 312:E348-E356. [PMID: 28174181 PMCID: PMC5406991 DOI: 10.1152/ajpendo.00453.2016] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 01/26/2017] [Accepted: 02/03/2017] [Indexed: 12/24/2022]
Abstract
The World Health Organization ranks hypertension the leading global risk factor for disease, specifically, cardiovascular disease. Blood pressure (BP) is higher in Westernized populations consuming Na+-rich processed foods than in isolated societies consuming K+-rich natural foods. Evidence suggests that lowering dietary Na+ is particularly beneficial in hypertensive individuals who consume a high-Na+ diet. Nonetheless, numerous population studies demonstrate a relationship between higher dietary K+, estimated from urinary excretion or dietary recall, and lower BP, regardless of Na+ intake. Interventional studies with K+ supplementation suggest that it provides a direct benefit; K+ may also be a marker for other beneficial components of a "natural" diet. Recent studies in rodent models indicate mechanisms for the K+ benefit: the distal tubule Na+-Cl- cotransporter (NCC) controls Na+ delivery downstream to the collecting duct, where Na+ reabsorbed by epithelial Na+ channels drives K+ secretion and excretion through K+ channels in the same region. High dietary K+ provokes a decrease in NCC activity to drive more K+ secretion (and Na+ excretion, analogous to the actions of a thiazide diuretic) whether Na+ intake is high or low; low dietary K+ provokes an increase in NCC activity and Na+ retention, also independent of dietary Na+ Together, the findings suggest that public health efforts directed toward increasing consumption of K+-rich natural foods would reduce BP and, thus, cardiovascular and kidney disease.
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Affiliation(s)
- Alicia A McDonough
- Department of Cell and Neurobiology, Keck School of Medicine of the University of Southern California, Los Angeles, California
| | - Luciana C Veiras
- Department of Cell and Neurobiology, Keck School of Medicine of the University of Southern California, Los Angeles, California
| | - Claire A Guevara
- Department of Cell and Neurobiology, Keck School of Medicine of the University of Southern California, Los Angeles, California
| | - Donna L Ralph
- Department of Cell and Neurobiology, Keck School of Medicine of the University of Southern California, Los Angeles, California
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38
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Al-Qusairi L, Basquin D, Roy A, Rajaram RD, Maillard MP, Subramanya AR, Staub O. Renal Tubular Ubiquitin-Protein Ligase NEDD4-2 Is Required for Renal Adaptation during Long-Term Potassium Depletion. J Am Soc Nephrol 2017; 28:2431-2442. [PMID: 28289184 DOI: 10.1681/asn.2016070732] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 02/01/2017] [Indexed: 11/03/2022] Open
Abstract
Adaptation of the organism to potassium (K+) deficiency requires precise coordination among organs involved in K+ homeostasis, including muscle, liver, and kidney. How the latter performs functional and molecular changes to ensure K+ retention is not well understood. Here, we investigated the role of ubiquitin-protein ligase NEDD4-2, which negatively regulates the epithelial sodium channel (ENaC), Na+/Cl- cotransporter (NCC), and with no-lysine-kinase 1 (WNK1). After dietary K+ restriction for 2 weeks, compared with control littermates, inducible renal tubular NEDD4-2 knockout (Nedd4LPax8/LC1 ) mice exhibited severe hypokalemia and urinary K+ wasting. Notably, expression of the ROMK K+ channel did not change in the distal convoluted tubule and decreased slightly in the cortical/medullary collecting duct, whereas BK channel abundance increased in principal cells of the connecting tubule/collecting ducts. However, K+ restriction also enhanced ENaC expression in Nedd4LPax8/LC1 mice, and treatment with the ENaC inhibitor, benzamil, reversed excessive K+ wasting. Moreover, K+ restriction increased WNK1 and WNK4 expression and enhanced SPAK-mediated NCC phosphorylation in Nedd4LPax8/LC1 mice, with no change in total NCC. We propose a mechanism in which NEDD4-2 deficiency exacerbates hypokalemia during dietary K+ restriction primarily through direct upregulation of ENaC, whereas increased BK channel expression has a less significant role. These changes outweigh the compensatory antikaliuretic effects of diminished ROMK expression, increased NCC phosphorylation, and enhanced WNK pathway activity in the distal convoluted tubule. Thus, NEDD4-2 has a crucial role in K+ conservation through direct and indirect effects on ENaC, distal nephron K+ channels, and WNK signaling.
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Affiliation(s)
- Lama Al-Qusairi
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland.,National Centre of Competence in Research "Kidney.ch", Zurich, Switzerland
| | - Denis Basquin
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland.,National Centre of Competence in Research "Kidney.ch", Zurich, Switzerland
| | - Ankita Roy
- Department of Medicine, University of Pittsburgh School of Medicine and VA Pittsburgh Healthcare System, Pittsburgh, Pennsylvania; and
| | - Renuga Devi Rajaram
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland.,National Centre of Competence in Research "Kidney.ch", Zurich, Switzerland
| | - Marc P Maillard
- Service of Nephrology, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
| | - Arohan R Subramanya
- Department of Medicine, University of Pittsburgh School of Medicine and VA Pittsburgh Healthcare System, Pittsburgh, Pennsylvania; and
| | - Olivier Staub
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland; .,National Centre of Competence in Research "Kidney.ch", Zurich, Switzerland
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39
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The renal TRPV4 channel is essential for adaptation to increased dietary potassium. Kidney Int 2017; 91:1398-1409. [PMID: 28187982 DOI: 10.1016/j.kint.2016.12.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 11/22/2016] [Accepted: 12/08/2016] [Indexed: 12/11/2022]
Abstract
To maintain potassium homeostasis, kidneys exert flow-dependent potassium secretion to facilitate kaliuresis in response to elevated dietary potassium intake. This process involves stimulation of calcium-activated large conductance maxi-K (BK) channels in the distal nephron, namely the connecting tubule and the collecting duct. Recent evidence suggests that the TRPV4 channel is a critical determinant of flow-dependent intracellular calcium elevations in these segments of the renal tubule. Here, we demonstrate that elevated dietary potassium intake (five percent potassium) increases renal TRPV4 mRNA and protein levels in an aldosterone-dependent manner and causes redistribution of the channel to the apical plasma membrane in native collecting duct cells. This, in turn, leads to augmented TRPV4-mediated flow-dependent calcium ion responses in freshly isolated split-opened collecting ducts from mice fed the high potassium diet. Genetic TRPV4 ablation greatly diminished BK channel activity in collecting duct cells pointing to a reduced capacity to excrete potassium. Consistently, elevated potassium intake induced hyperkalemia in TRPV4 knockout mice due to deficient renal potassium excretion. Thus, regulation of TRPV4 activity in the distal nephron by dietary potassium is an indispensable component of whole body potassium balance.
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40
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West CA, Sasser JM, Baylis C. The enigma of continual plasma volume expansion in pregnancy: critical role of the renin-angiotensin-aldosterone system. Am J Physiol Renal Physiol 2016; 311:F1125-F1134. [PMID: 27707703 PMCID: PMC6189751 DOI: 10.1152/ajprenal.00129.2016] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 09/29/2016] [Indexed: 12/27/2022] Open
Abstract
Pregnancy is characterized by avid renal sodium retention and plasma volume expansion in the presence of decreased blood pressure. Decreased maternal blood pressure is a consequence of reduced systemic vascular tone, which results from an increased production of vasodilators [nitric oxide (NO), prostaglandins, and relaxin] and decreased vascular responsiveness to the potent vasoconstrictor (angiotensin II). The kidneys participate in this vasodilatory response, resulting in marked increases in renal plasma flow and glomerular filtration rate (GFR) during pregnancy. In women, sodium retention drives plasma volume expansion (∼40%) and is necessary for perfusion of the growing uterus and fetus. For there to be avid sodium retention in the presence of the potent natriuretic influences of increased NO and elevated GFR, there must be modifications of the tubules to prevent salt wasting. The purpose of this review is to summarize these adaptations.
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Affiliation(s)
- Crystal A West
- Department of Medicine, Georgetown University, Washington, District of Columbia;
| | - Jennifer M Sasser
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi; and
| | - Chris Baylis
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida
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41
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Thomas L, Bettoni C, Knöpfel T, Hernando N, Biber J, Wagner CA. Acute Adaption to Oral or Intravenous Phosphate Requires Parathyroid Hormone. J Am Soc Nephrol 2016; 28:903-914. [PMID: 28246304 DOI: 10.1681/asn.2016010082] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 08/22/2016] [Indexed: 12/17/2022] Open
Abstract
Phosphate (Pi) homeostasis is regulated by renal, intestinal, and endocrine mechanisms through which Pi intake stimulates parathyroid hormone (PTH) and fibroblast growth factor-23 secretion, increasing phosphaturia. Mechanisms underlying the early adaptive phase and the role of the intestine, however, remain ill defined. We investigated mineral, endocrine, and renal responses during the first 4 hours after intravenous and intragastric Pi loading in rats. Intravenous Pi loading (0.5 mmol) caused a transient rise in plasma Pi levels and creatinine clearance and an increase in phosphaturia within 10 minutes. Plasma calcium levels fell and PTH levels increased within 10 minutes and remained low or high, respectively. Fibroblast growth factor-23, 1,25-(OH)2-vitamin D3, and insulin concentrations did not respond, but plasma dopamine levels increased by 4 hours. In comparison, gastric Pi loading elicited similar but delayed phosphaturia and endocrine responses but did not affect plasma mineral levels. Either intravenous or gastric loading led to decreased expression and activity of renal Pi transporters after 4 hours. In parathyroidectomized rats, however, only intravenous Pi loading caused phosphaturia, which was blunted and transient compared with that in intact rats. Intravenous but not gastric Pi loading in parathyroidectomized rats also led to higher creatinine clearance and lower plasma calcium levels but did not reduce the expression or activity of Pi transporters. This evidence suggests that an intravenous or intestinal Pi bolus causes rapid phosphaturia through mechanisms requiring PTH and downregulation of renal Pi transporters but does not support a role of the intestine in stimulating renal clearance of Pi.
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Affiliation(s)
- Linto Thomas
- Institute of Physiology, University of Zurich, Zurich, Switzerland; and National Centre for Competence in Research, Zurich, Switzerland
| | - Carla Bettoni
- Institute of Physiology, University of Zurich, Zurich, Switzerland; and National Centre for Competence in Research, Zurich, Switzerland
| | - Thomas Knöpfel
- Institute of Physiology, University of Zurich, Zurich, Switzerland; and National Centre for Competence in Research, Zurich, Switzerland
| | - Nati Hernando
- Institute of Physiology, University of Zurich, Zurich, Switzerland; and National Centre for Competence in Research, Zurich, Switzerland
| | - Jürg Biber
- Institute of Physiology, University of Zurich, Zurich, Switzerland; and National Centre for Competence in Research, Zurich, Switzerland
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland; and National Centre for Competence in Research, Zurich, Switzerland
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42
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Kaslow AM, Riquier-Brison A, Peti-Peterdi J, Shillingford N, HaDuong J, Venkatramani R, Gayer CP. An ectopic renin-secreting adrenal corticoadenoma in a child with malignant hypertension. Physiol Rep 2016; 4:4/5/e12728. [PMID: 26997629 PMCID: PMC4823597 DOI: 10.14814/phy2.12728] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
A previously healthy 7‐year‐old male presented with hypertensive emergency, hypokalemia, and elevated plasma renin activity and aldosterone levels. There was no evidence of virilization or cushingoid features. MRI of the abdomen revealed a large (5 × 5 × 3 cm) peripherally enhancing, heterogeneous mass arising from the left adrenal gland. The patient was treated for a suspected pheochromocytoma. However, his blood pressure was not responsive to alpha‐blockade. Blood pressure was controlled with a calcium channel blocker and an angiotensin‐converting enzyme (ACE) inhibitor. A complete surgical resection of the mass was performed. Postoperatively, his blood pressure normalized and he did not require antihypertensives. On pathological examination, the tumor tissue stained negative for chromogranin and positive for renin. The final diagnosis was renin‐secreting adrenal corticoadenoma, an extremely rare adrenal tumor not previously reported in a pediatric patient. Malignant hypertension due to a renin‐secreting tumor may need to be distinguished from a pheochromocytoma if alpha‐adrenergic blockade is ineffective.
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Affiliation(s)
| | | | | | | | | | | | - Christopher P Gayer
- Children's Hospital Los Angeles, Los Angeles, California Keck School of Medicine of USC, Los Angeles, California
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43
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Walter C, Tanfous MB, Igoudjil K, Salhi A, Escher G, Crambert G. H,K-ATPase type 2 contributes to salt-sensitive hypertension induced by K(+) restriction. Pflugers Arch 2016; 468:1673-83. [PMID: 27562425 DOI: 10.1007/s00424-016-1872-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 08/15/2016] [Accepted: 08/17/2016] [Indexed: 01/24/2023]
Abstract
In industrialized countries, a large part of the population is daily exposed to low K(+) intake, a situation correlated with the development of salt-sensitive hypertension. Among many processes, adaptation to K(+)-restriction involves the stimulation of H,K-ATPase type 2 (HKA2) in the kidney and colon and, in this study, we have investigated whether HKA2 also contributes to the determination of blood pressure (BP). By using wild-type (WT) and HKA2-null mice (HKA2 KO), we showed that after 4 days of K(+) restriction, WT remain normokalemic and normotensive (112 ± 3 mmHg) whereas HKA2 KO mice exhibit hypokalemia and hypotension (104 ± 2 mmHg). The decrease of BP in HKA2 KO is due to the absence of NaCl-cotransporter (NCC) stimulation, leading to renal loss of salt and decreased extracellular volume (by 20 %). These effects are likely related to the renal resistance to vasopressin observed in HKA2 KO that may be explained, in part by the increased production of prostaglandin E2 (PGE2). In WT, the stimulation of NCC induced by K(+)-restriction is responsible for the elevation in BP when salt intake increases, an effect blunted in HKA2-null mice. The presence of an activated HKA2 is therefore required to limit the decrease in plasma [K(+)] but also contributes to the development of salt-sensitive hypertension.
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Affiliation(s)
- Christine Walter
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, Université Paris Descartes, F-75006, Paris, France.,CNRS ERL 8228 - Centre de Recherche des Cordeliers - Laboratoire de Métabolisme et Physiologie Rénale, F-75006, Paris, France
| | - Mariem Ben Tanfous
- Faculté des Sciences de Tunis El Manar, Campus Universitaire 2092, El Manar Tunis, Tunisie
| | - Katia Igoudjil
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, Université Paris Descartes, F-75006, Paris, France.,CNRS ERL 8228 - Centre de Recherche des Cordeliers - Laboratoire de Métabolisme et Physiologie Rénale, F-75006, Paris, France
| | - Amel Salhi
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, Université Paris Descartes, F-75006, Paris, France.,CNRS ERL 8228 - Centre de Recherche des Cordeliers - Laboratoire de Métabolisme et Physiologie Rénale, F-75006, Paris, France
| | - Geneviève Escher
- Departement für Nephrologie, Hypertonie und klinische Pharmakologie, Universitätsspital Bern - Inselspital, CH-3010, Bern, Switzerland
| | - Gilles Crambert
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, Université Paris Descartes, F-75006, Paris, France. .,CNRS ERL 8228 - Centre de Recherche des Cordeliers - Laboratoire de Métabolisme et Physiologie Rénale, F-75006, Paris, France.
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44
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Cremades A, Del Rio-Garcia J, Lambertos A, López-Garcia C, Peñafiel R. Tissue-specific regulation of potassium homeostasis by high doses of cationic amino acids. SPRINGERPLUS 2016; 5:616. [PMID: 27330882 PMCID: PMC4870509 DOI: 10.1186/s40064-016-2224-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 04/22/2016] [Indexed: 01/19/2023]
Abstract
The administration of l-arginine hydrochloride has been used for testing pituitary secretion in humans, and as an experimental model for induction of acute pancreatitis in rats and mice. Whereas in the first case, the administration of the amino acid is associated with hiperkalemia, in the model of acute pancreatitis no data are available on possible changes in potassium homeostasis. The present study shows that the acute administration to mice of l-arginine hydrochloride or other cationic amino acids almost duplicate plasma potassium levels. This effect was associated to a marked decrease of tissue potassium in both pancreas and liver. No changes were found in other tissues. These changes cannot be ascribed to the large load of chloride ions, since similar effects were produced when l-ornithine aspartate was administered. The changes in potassium levels were dependent on the dose. The displacement of intracellular potassium from the liver and pancreas to the extracellular compartment appears to be dependent on the entry of the cationic amino acid, since the administration of an equivalent dose of alfa-difluoromethyl ornithine HCl (DFMO), a non physiological analog of l-ornithine, which is poorly taken by the tissues in comparison with the physiological cationic amino acids, did not produce any change in potassium levels in pancreas and liver. The analyses of the expression of cationic amino acid transporters (CAT) suggest that the CAT-2 transporter may be implicated in the potassium/cationic amino acid interchange in liver and pancreas. The possible physiological or pathological relevance of these findings is discussed.
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Affiliation(s)
- Asunción Cremades
- Department of Pharmacology, Faculty of Medicine, University of Murcia, Murcia, Spain ; Biomedical Research Institute of Murcia (IMIB), Murcia, Spain
| | - Jesús Del Rio-Garcia
- Department of Pharmacology, Faculty of Medicine, University of Murcia, Murcia, Spain
| | - Ana Lambertos
- Department of Biochemistry, Molecular Biology B and Immunology, School of Medicine, University of Murcia, 30100 Murcia, Spain
| | - Carlos López-Garcia
- Department of Pharmacology, Faculty of Medicine, University of Murcia, Murcia, Spain
| | - Rafael Peñafiel
- Department of Biochemistry, Molecular Biology B and Immunology, School of Medicine, University of Murcia, 30100 Murcia, Spain ; Biomedical Research Institute of Murcia (IMIB), Murcia, Spain
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45
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Israr T, Rakha A, Sohail M, Rashid S, Shehzad A. Salt reduction in baked products: Strategies and constraints. Trends Food Sci Technol 2016. [DOI: 10.1016/j.tifs.2016.03.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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46
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Al-Qusairi L, Basquin D, Roy A, Stifanelli M, Rajaram RD, Debonneville A, Nita I, Maillard M, Loffing J, Subramanya AR, Staub O. Renal tubular SGK1 deficiency causes impaired K+ excretion via loss of regulation of NEDD4-2/WNK1 and ENaC. Am J Physiol Renal Physiol 2016; 311:F330-42. [PMID: 27009335 DOI: 10.1152/ajprenal.00002.2016] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2016] [Accepted: 03/21/2016] [Indexed: 11/22/2022] Open
Abstract
The stimulation of postprandial K(+) clearance involves aldosterone-independent and -dependent mechanisms. In this context, serum- and glucocorticoid-induced kinase (SGK)1, a ubiquitously expressed kinase, is one of the primary aldosterone-induced proteins in the aldosterone-sensitive distal nephron. Germline inactivation of SGK1 suggests that this kinase is fundamental for K(+) excretion under conditions of K(+) load, but the specific role of renal SGK1 remains elusive. To avoid compensatory mechanisms that may occur during nephrogenesis, we used inducible, nephron-specific Sgk1(Pax8/LC1) mice to assess the role of renal tubular SGK1 in K(+) regulation. Under a standard diet, these animals exhibited normal K(+) handling. When challenged by a high-K(+) diet, they developed severe hyperkalemia accompanied by a defect in K(+) excretion. Molecular analysis revealed reduced neural precursor cell expressed developmentally downregulated protein (NEDD)4-2 phosphorylation and total expression. γ-Epithelial Na(+) channel (ENaC) expression and α/γENaC proteolytic processing were also decreased in mutant mice. Moreover, with no lysine kinase (WNK)1, which displayed in control mice punctuate staining in the distal convoluted tubule and diffuse distribution in the connecting tubule/cortical colleting duct, was diffused in the distal convoluted tubule and less expressed in the connecting tubule/collecting duct of Sgk(Pax8/LC1) mice. Moreover, Ste20-related proline/alanine-rich kinase phosphorylation, and Na(+)-Cl(-) cotransporter phosphorylation/apical localization were reduced in mutant mice. Consistent with the altered WNK1 expression, increased renal outer medullary K(+) channel apical localization was observed. In conclusion, our data suggest that renal tubular SGK1 is important in the regulation of K(+) excretion via the control of NEDD4-2, WNK1, and ENaC.
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Affiliation(s)
- Lama Al-Qusairi
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland; National Centre of Competence in Research "Kidney.ch," Lausanne, Switzerland
| | - Denis Basquin
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland; National Centre of Competence in Research "Kidney.ch," Lausanne, Switzerland
| | - Ankita Roy
- Department of Medicine, University of Pittsburgh School of Medicine and Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, Pennsylvania
| | - Matteo Stifanelli
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Renuga Devi Rajaram
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Anne Debonneville
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Izabela Nita
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Marc Maillard
- Service of Nephrology, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
| | - Johannes Loffing
- Institute of Anatomy, University of Zurich, Zurich, Switzerland; and National Centre of Competence in Research "Kidney.ch," Lausanne, Switzerland
| | - Arohan R Subramanya
- Department of Medicine, University of Pittsburgh School of Medicine and Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, Pennsylvania
| | - Olivier Staub
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland; National Centre of Competence in Research "Kidney.ch," Lausanne, Switzerland
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47
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Wu X, Kim H, Seravalli J, Barycki JJ, Hart PJ, Gohara DW, Di Cera E, Jung WH, Kosman DJ, Lee J. Potassium and the K+/H+ Exchanger Kha1p Promote Binding of Copper to ApoFet3p Multi-copper Ferroxidase. J Biol Chem 2016; 291:9796-806. [PMID: 26966178 DOI: 10.1074/jbc.m115.700500] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Indexed: 01/24/2023] Open
Abstract
Acquisition and distribution of metal ions support a number of biological processes. Here we show that respiratory growth of and iron acquisition by the yeast Saccharomyces cerevisiae relies on potassium (K(+)) compartmentalization to the trans-Golgi network via Kha1p, a K(+)/H(+) exchanger. K(+) in the trans-Golgi network facilitates binding of copper to the Fet3p multi-copper ferroxidase. The effect of K(+) is not dependent on stable binding with Fet3p or alteration of the characteristics of the secretory pathway. The data suggest that K(+) acts as a chemical factor in Fet3p maturation, a role similar to that of cations in folding of nucleic acids. Up-regulation of KHA1 gene in response to iron limitation via iron-specific transcription factors indicates that K(+) compartmentalization is linked to cellular iron homeostasis. Our study reveals a novel functional role of K(+) in the binding of copper to apoFet3p and identifies a K(+)/H(+) exchanger at the secretory pathway as a new molecular factor associated with iron uptake in yeast.
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Affiliation(s)
- Xiaobin Wu
- From the Department of Biochemistry and Redox Biology Center, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0664, College of Life and Environmental Sciences, Shanghai Normal University, Shanghai, China 200234
| | - Heejeong Kim
- From the Department of Biochemistry and Redox Biology Center, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0664
| | - Javier Seravalli
- From the Department of Biochemistry and Redox Biology Center, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0664
| | - Joseph J Barycki
- From the Department of Biochemistry and Redox Biology Center, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0664
| | - P John Hart
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas 78229-3900
| | - David W Gohara
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, Missouri 63104
| | - Enrico Di Cera
- Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, Missouri 63104
| | - Won Hee Jung
- Department of Systems Biotechnology, Chung-Ang University, Anseong, Korea 456-756, and
| | - Daniel J Kosman
- Department of Biochemistry, University at Buffalo, Buffalo, New York 14214-3000
| | - Jaekwon Lee
- From the Department of Biochemistry and Redox Biology Center, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0664,
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Larsen CK, Jensen IS, Sorensen MV, de Bruijn PI, Bleich M, Praetorius HA, Leipziger J. Hyperaldosteronism after decreased renal K+ excretion in KCNMB2 knockout mice. Am J Physiol Renal Physiol 2016; 310:F1035-46. [PMID: 26962098 DOI: 10.1152/ajprenal.00010.2016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 03/08/2016] [Indexed: 11/22/2022] Open
Abstract
The kidney is the primary organ ensuring K(+) homeostasis. K(+) is secreted into the urine in the distal tubule by two mechanisms: by the renal outer medullary K(+) channel (Kir1.1) and by the Ca(2+)-activated K(+) channel (KCa1.1). Here, we report a novel knockout mouse of the β2-subunit of the KCa1.1 channel (KCNMB2), which displays hyperaldosteronism after decreased renal K(+) excretion. KCNMB2(-/-) mice displayed hyperaldosteronism, normal plasma K(+) concentration, and produced dilute urine with decreased K(+) concentration. The normokalemia indicated that hyperaldosteronism did not result from primary aldosteronism. Activation of the renin-angiotensin-aldosterone system was also ruled out as renal renin mRNA expression was reduced in KCNMB2(-/-) mice. Renal K(+) excretion rates were similar in the two genotypes; however, KCNMB2(-/-) mice required elevated plasma aldosterone to achieve K(+) balance. Blockade of the mineralocorticoid receptor with eplerenone triggered mild hyperkalemia and unmasked reduced renal K(+) excretion in KCNMB2(-/-) mice. Knockout mice for the α-subunit of the KCa1.1 channel (KCNMA1(-/-) mice) have hyperaldosteronism, are hypertensive, and lack flow-induced K(+) secretion. KCNMB2(-/-) mice share the phenotypic traits of normokalemia and hyperaldosteronism with KCNMA1(-/-) mice but were normotensive and displayed intact flow-induced K(+) secretion. Despite elevated plasma aldosterone, KNCMB2(-/-) mice did not display salt-sensitive hypertension and were able to decrease plasma aldosterone on a high-Na(+) diet, although plasma aldosterone remained elevated in KCNMB2(-/-) mice. In summary, KCNMB2(-/-) mice have a reduced ability to excrete K(+) into the urine but achieve K(+) balance through an aldosterone-mediated, β2-independent mechanism. The phenotype of KCNMB2 mice was similar but milder than the phenotype of KCNMA1(-/-) mice.
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Affiliation(s)
- Casper K Larsen
- Department of Biomedicine, Physiology, and Health, Aarhus University, Aarhus, Denmark
| | - Iben S Jensen
- Department of Biomedicine, Physiology, and Health, Aarhus University, Aarhus, Denmark
| | - Mads V Sorensen
- Department of Biomedicine, Physiology, and Health, Aarhus University, Aarhus, Denmark; Aarhus Institute for Advanced Studies, Aarhus University, Aarhus, Denmark; and
| | - Pauline I de Bruijn
- Department of Biomedicine, Physiology, and Health, Aarhus University, Aarhus, Denmark
| | - Markus Bleich
- Institute of Physiology, Christian-Albrechts-University, Kiel, Germany
| | - Helle A Praetorius
- Department of Biomedicine, Physiology, and Health, Aarhus University, Aarhus, Denmark
| | - Jens Leipziger
- Department of Biomedicine, Physiology, and Health, Aarhus University, Aarhus, Denmark;
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49
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Evidence for a gastrointestinal–renal kaliuretic signaling axis in humans. Kidney Int 2015; 88:1383-1391. [DOI: 10.1038/ki.2015.243] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Revised: 06/18/2015] [Accepted: 06/18/2015] [Indexed: 01/20/2023]
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50
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Olanrewaju H, Purswell J, Collier S, Branton S. Effects of color temperatures (Kelvin) of LED bulbs on blood physiological variables of broilers grown to heavy weights. Poult Sci 2015; 94:1721-8. [DOI: 10.3382/ps/pev139] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/14/2015] [Indexed: 11/20/2022] Open
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