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Wu P, Li ST, Shu TT, Mao ZH, Fu WJ, Yang YY, Pan SK, Liu DW, Liu ZS, Gao ZX. Impaired distal renal potassium handling in streptozotocin-induced diabetic mice. Am J Physiol Renal Physiol 2024; 327:F158-F170. [PMID: 38779755 DOI: 10.1152/ajprenal.00240.2023] [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: 08/14/2023] [Revised: 05/13/2024] [Accepted: 05/13/2024] [Indexed: 05/25/2024] Open
Abstract
Diabetes is closely associated with K+ disturbances during disease progression and treatment. However, it remains unclear whether K+ imbalance occurs in diabetes with normal kidney function. In this study, we examined the effects of dietary K+ intake on systemic K+ balance and renal K+ handling in streptozotocin (STZ)-induced diabetic mice. The control and STZ mice were fed low or high K+ diet for 7 days to investigate the role of dietary K+ intake in renal K+ excretion and K+ homeostasis and to explore the underlying mechanism by evaluating K+ secretion-related transport proteins in distal nephrons. K+-deficient diet caused excessive urinary K+ loss, decreased daily K+ balance, and led to severe hypokalemia in STZ mice compared with control mice. In contrast, STZ mice showed an increased daily K+ balance and elevated plasma K+ level under K+-loading conditions. Dysregulation of the NaCl cotransporter (NCC), epithelial Na+ channel (ENaC), and renal outer medullary K+ channel (ROMK) was observed in diabetic mice fed either low or high K+ diet. Moreover, amiloride treatment reduced urinary K+ excretion and corrected hypokalemia in K+-restricted STZ mice. On the other hand, inhibition of SGLT2 by dapagliflozin promoted urinary K+ excretion and normalized plasma K+ levels in K+-supplemented STZ mice, at least partly by increasing ENaC activity. We conclude that STZ mice exhibited abnormal K+ balance and impaired renal K+ handling under either low or high K+ diet, which could be primarily attributed to the dysfunction of ENaC-dependent renal K+ excretion pathway, despite the possible role of NCC.NEW & NOTEWORTHY Neither low dietary K+ intake nor high dietary K+ intake effectively modulates renal K+ excretion and K+ homeostasis in STZ mice, which is closely related to the abnormality of ENaC expression and activity. SGLT2 inhibitor increases urinary K+ excretion and reduces plasma K+ level in STZ mice under high dietary K+ intake, an effect that may be partly due to the upregulation of ENaC activity.
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Affiliation(s)
- Peng Wu
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, People's Republic of China
- Institute of Nephrology, Zhengzhou University, Zhengzhou, People's Republic of China
- Henan Province Research Center for Kidney Disease, Zhengzhou, People's Republic of China
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, People's Republic of China
| | - Shu-Ting Li
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, People's Republic of China
- Institute of Nephrology, Zhengzhou University, Zhengzhou, People's Republic of China
- Henan Province Research Center for Kidney Disease, Zhengzhou, People's Republic of China
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, People's Republic of China
| | - Ting-Ting Shu
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, People's Republic of China
- Institute of Nephrology, Zhengzhou University, Zhengzhou, People's Republic of China
- Henan Province Research Center for Kidney Disease, Zhengzhou, People's Republic of China
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, People's Republic of China
| | - Zi-Hui Mao
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, People's Republic of China
- Institute of Nephrology, Zhengzhou University, Zhengzhou, People's Republic of China
- Henan Province Research Center for Kidney Disease, Zhengzhou, People's Republic of China
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, People's Republic of China
| | - Wen-Jia Fu
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, People's Republic of China
- Institute of Nephrology, Zhengzhou University, Zhengzhou, People's Republic of China
- Henan Province Research Center for Kidney Disease, Zhengzhou, People's Republic of China
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, People's Republic of China
| | - Yuan-Yuan Yang
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, People's Republic of China
- Institute of Nephrology, Zhengzhou University, Zhengzhou, People's Republic of China
- Henan Province Research Center for Kidney Disease, Zhengzhou, People's Republic of China
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, People's Republic of China
| | - Shao-Kang Pan
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, People's Republic of China
- Institute of Nephrology, Zhengzhou University, Zhengzhou, People's Republic of China
- Henan Province Research Center for Kidney Disease, Zhengzhou, People's Republic of China
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, People's Republic of China
| | - Dong-Wei Liu
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, People's Republic of China
- Institute of Nephrology, Zhengzhou University, Zhengzhou, People's Republic of China
- Henan Province Research Center for Kidney Disease, Zhengzhou, People's Republic of China
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, People's Republic of China
| | - Zhang-Suo Liu
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, People's Republic of China
- Institute of Nephrology, Zhengzhou University, Zhengzhou, People's Republic of China
- Henan Province Research Center for Kidney Disease, Zhengzhou, People's Republic of China
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, People's Republic of China
| | - Zhong-Xiuzi Gao
- Traditional Chinese Medicine Integrated Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, People's Republic of China
- Institute of Nephrology, Zhengzhou University, Zhengzhou, People's Republic of China
- Henan Province Research Center for Kidney Disease, Zhengzhou, People's Republic of China
- Key Laboratory of Precision Diagnosis and Treatment for Chronic Kidney Disease in Henan Province, Zhengzhou, People's Republic of China
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Zhang Y, Bock F, Ferdaus M, Arroyo JP, L Rose K, Patel P, Denton JS, Delpire E, Weinstein AM, Zhang MZ, Harris RC, Terker AS. Low potassium activation of proximal mTOR/AKT signaling is mediated by Kir4.2. Nat Commun 2024; 15:5144. [PMID: 38886379 PMCID: PMC11183202 DOI: 10.1038/s41467-024-49562-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: 08/31/2023] [Accepted: 06/07/2024] [Indexed: 06/20/2024] Open
Abstract
The renal epithelium is sensitive to changes in blood potassium (K+). We identify the basolateral K+ channel, Kir4.2, as a mediator of the proximal tubule response to K+ deficiency. Mice lacking Kir4.2 have a compensated baseline phenotype whereby they increase their distal transport burden to maintain homeostasis. Upon dietary K+ depletion, knockout animals decompensate as evidenced by increased urinary K+ excretion and development of a proximal renal tubular acidosis. Potassium wasting is not proximal in origin but is caused by higher ENaC activity and depends upon increased distal sodium delivery. Three-dimensional imaging reveals Kir4.2 knockouts fail to undergo proximal tubule expansion, while the distal convoluted tubule response is exaggerated. AKT signaling mediates the dietary K+ response, which is blunted in Kir4.2 knockouts. Lastly, we demonstrate in isolated tubules that AKT phosphorylation in response to low K+ depends upon mTORC2 activation by secondary changes in Cl- transport. Data support a proximal role for cell Cl- which, as it does along the distal nephron, responds to K+ changes to activate kinase signaling.
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Affiliation(s)
- Yahua Zhang
- Division of Nephrology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Center for Kidney Disease, Nashville, TN, USA
| | - Fabian Bock
- Division of Nephrology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Center for Kidney Disease, Nashville, TN, USA
| | - Mohammed Ferdaus
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Juan Pablo Arroyo
- Division of Nephrology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Center for Kidney Disease, Nashville, TN, USA
| | - Kristie L Rose
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA
- Mass Spectrometry Research Center, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Purvi Patel
- Mass Spectrometry Research Center, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Jerod S Denton
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Eric Delpire
- Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Alan M Weinstein
- Department of Physiology and Biophysics, Weil Medical College, New York, NY, USA
| | - Ming-Zhi Zhang
- Division of Nephrology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Center for Kidney Disease, Nashville, TN, USA
| | - Raymond C Harris
- Division of Nephrology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
- Vanderbilt Center for Kidney Disease, Nashville, TN, USA
- Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN, USA
| | - Andrew S Terker
- Division of Nephrology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA.
- Vanderbilt Center for Kidney Disease, Nashville, TN, USA.
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Gritter M, Wei KY, Wouda RD, Musterd-Bhaggoe UM, Dijkstra KL, Kers J, Ramakers C, Vogt L, de Borst MH, Danser AHJ, Hoorn EJ, Rotmans JI. Chronic kidney disease increases the susceptibility to negative effects of low and high potassium intake. Nephrol Dial Transplant 2024; 39:795-807. [PMID: 37813819 PMCID: PMC11045281 DOI: 10.1093/ndt/gfad220] [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: 07/09/2023] [Indexed: 10/11/2023] Open
Abstract
BACKGROUND Dietary potassium (K+) has emerged as a modifiable factor for cardiovascular and kidney health in the general population, but its role in people with chronic kidney disease (CKD) is unclear. Here, we hypothesize that CKD increases the susceptibility to the negative effects of low and high K+ diets. METHODS We compared the effects of low, normal and high KChloride (KCl) diets and a high KCitrate diet for 4 weeks in male rats with normal kidney function and in male rats with CKD using the 5/6th nephrectomy model (5/6Nx). RESULTS Compared with rats with normal kidney function, 5/6Nx rats on the low KCl diet developed more severe extracellular and intracellular K+ depletion and more severe kidney injury, characterized by nephromegaly, infiltration of T cells and macrophages, decreased estimated glomerular filtration rate and increased albuminuria. The high KCl diet caused hyperkalemia, hyperaldosteronism, hyperchloremic metabolic acidosis and severe hypertension in 5/6Nx but not in sham rats. The high KCitrate diet caused hypochloremic metabolic alkalosis but attenuated hypertension despite higher abundance of the phosphorylated sodium chloride cotransporter (pNCC) and similar levels of plasma aldosterone and epithelial sodium channel abundance. All 5/6Nx groups had more collagen deposition than the sham groups and this effect was most pronounced in the high KCitrate group. Plasma aldosterone correlated strongly with kidney collagen deposition. CONCLUSIONS CKD increases the susceptibility to negative effects of low and high K+ diets in male rats, although the injury patterns are different. The low K+ diet caused inflammation, nephromegaly and kidney function decline, whereas the high K+ diet caused hypertension, hyperaldosteronism and kidney fibrosis. High KCitrate attenuated the hypertensive but not the pro-fibrotic effect of high KCl, which may be attributable to K+-induced aldosterone secretion. Our data suggest that especially in people with CKD it is important to identify the optimal threshold of dietary K+ intake.
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Affiliation(s)
- Martin Gritter
- Department of Internel Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, Rotterdam, The Netherlands
- Department of Internal Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - Kuang-Yu Wei
- Department of Internel Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, Rotterdam, The Netherlands
- Department of Internal Medicine, Division of Nephrology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Rosa D Wouda
- Department of Internal Medicine, Section of Nephrology, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Usha M Musterd-Bhaggoe
- Department of Internel Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Kyra L Dijkstra
- Pathology, Leiden University Medical Center, Leiden, The Netherlands
| | - Jesper Kers
- Pathology, Leiden University Medical Center, Leiden, The Netherlands
- Pathology, Amsterdam University Medical Center, Amsterdam, The Netherlands
- Van ‘t Hoff Institute for Molecular Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | | | - Liffert Vogt
- Department of Internal Medicine, Section of Nephrology, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Martin H de Borst
- Division of Nephrology, Department of Internal Medicine, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Alexander H J Danser
- Division of Pharmacology and Vascular Medicine, Department of Internal Medicine, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Ewout J Hoorn
- Department of Internel Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Joris I Rotmans
- Department of Internal Medicine, Leiden University Medical Center, Leiden, The Netherlands
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Derakhshandeh-Rishehri SM, Franco LP, Hua Y, Herder C, Kalhoff H, Frassetto LA, Wudy SA, Remer T. Higher Renal Net Acid Excretion, but Not Higher Phosphate Excretion, during Childhood and Adolescence Associates with the Circulating Renal Tubular Injury Marker Interleukin-18 in Adulthood. Int J Mol Sci 2024; 25:1408. [PMID: 38338685 PMCID: PMC10855358 DOI: 10.3390/ijms25031408] [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: 12/07/2023] [Revised: 01/17/2024] [Accepted: 01/19/2024] [Indexed: 02/12/2024] Open
Abstract
High dietary phosphorus intake (P-In) and high acid loads may adversely affect kidney function. In animal models, excessive phosphorus intake causes renal injury, which, in humans, is also inducible by chronic metabolic acidosis. We thus examined whether habitually high P-In and endogenous acid production during childhood and adolescence may be early indicators of incipient renal inflammatory processes later in adulthood. P-In and acid-base status were longitudinally and exclusively determined by biomarker-based assessment in 277 healthy children, utilizing phosphate and net acid excretion (NAE) measurements in 24 h urine samples repeatedly collected between the ages of 3 and 17 years. Standard deviation scores (by sex and age) were calculated for anthropometric data and for the urinary biomarkers available within age range 3-17 years. Multivariable linear regression was used to analyze the relations of phosphate excretion and NAE with the adulthood outcome circulating interleukin-18 (IL-18), a marker of inflammation and kidney dysfunction. After adjusting for growth- and adulthood-related covariates and pro-inflammatory biomarkers to rule out confounding by non-renal inflammatory processes, regression models revealed a significant positive relationship of long-term NAE (p = 0.01), but not of long-term phosphate excretion with adult serum IL-18. Similar significant positive regression results were obtained after replacing NAE with 24 h urinary ammonium excretion as the exposition variable. Our results suggest that even moderate elevations in renal ammonia production, as caused by habitually higher acid loading during growth, may affect the intrarenal pro-inflammatory system in the long-term, known to be boosted by acidosis-induced raised ammoniagenesis.
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Affiliation(s)
| | - Luciana Peixoto Franco
- DONALD Study Center, Department of Nutritional Epidemiology, Institute of Nutrition and Food Science, University of Bonn, 44225 Dortmund, Germany
| | - Yifan Hua
- DONALD Study Center, Department of Nutritional Epidemiology, Institute of Nutrition and Food Science, University of Bonn, 44225 Dortmund, Germany
| | - Christian Herder
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany
- German Center for Diabetes Research (DZD), 85764 München-Neuherberg, Germany
- Department of Endocrinology and Diabetology, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany
| | - Hermann Kalhoff
- Research Department of Child Nutrition, St. Josef-Hospital, University Hospital of Pediatrics and Adolescent Medicine, Ruhr-University Bochum, 44791 Bochum, Germany
- Pediatric Clinic Dortmund, 44137 Dortmund, Germany
| | - Lynda A. Frassetto
- Department of Medicine, Division of Nephrology, University of California San Francisco, San Francisco, CA 94143, USA
| | - Stefan A. Wudy
- Pediatric Endocrinology and Diabetology, Center of Child and Adolescent Medicine, Justus Liebig University, 35392 Giessen, Germany
| | - Thomas Remer
- DONALD Study Center, Department of Nutritional Epidemiology, Institute of Nutrition and Food Science, University of Bonn, 44225 Dortmund, Germany
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