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Küng CJ, Daryadel A, Fuente R, Haykir B, de Angelis MH, Hernando N, Rubio-Aliaga I, Wagner CA. A novel mouse model for familial hypocalciuric hypercalcemia (FHH1) reveals PTH-dependent and independent CaSR defects. Pflugers Arch 2024; 476:833-845. [PMID: 38386045 PMCID: PMC11033242 DOI: 10.1007/s00424-024-02927-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 02/11/2024] [Accepted: 02/12/2024] [Indexed: 02/23/2024]
Abstract
The Calcium-sensing receptor (CaSR) senses extracellular calcium, regulates parathyroid hormone (PTH) secretion, and has additional functions in various organs related to systemic and local calcium and mineral homeostasis. Familial hypocalciuric hypercalcemia type I (FHH1) is caused by heterozygous loss-of-function mutations in the CaSR gene, and is characterized by the combination of hypercalcemia, hypocalciuria, normal to elevated PTH, and facultatively hypermagnesemia and mild bone mineralization defects. To date, only heterozygous Casr null mice have been available as model for FHH1. Here we present a novel mouse FHH1 model identified in a large ENU-screen that carries an c.2579 T > A (p.Ile859Asn) variant in the Casr gene (CasrBCH002 mice). In order to dissect direct effects of the genetic variant from PTH-dependent effects, we crossed CasrBCH002 mice with PTH deficient mice. Heterozygous CasrBCH002 mice were fertile, had normal growth and body weight, were hypercalcemic and hypermagnesemic with inappropriately normal PTH levels and urinary calcium excretion replicating some features of FHH1. Hypercalcemia and hypermagnesemia were independent from PTH and correlated with higher expression of claudin 16 and 19 in kidneys. Likewise, reduced expression of the renal TRPM6 channel in CasrBCH002 mice was not dependent on PTH. In bone, mutations in Casr rescued the bone phenotype observed in Pth null mice by increasing osteoclast numbers and improving the columnar pattern of chondrocytes in the growth zone. In summary, CasrBCH002 mice represent a new model to study FHH1 and our results indicate that only a part of the phenotype is driven by PTH.
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Affiliation(s)
- Catharina J Küng
- Institute of Physiology, University of Zürich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Arezoo Daryadel
- Institute of Physiology, University of Zürich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Rocio Fuente
- Institute of Physiology, University of Zürich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
- Department of Morphology and Cellular Biology, University of Oviedo, Oviedo, Spain
| | - Betül Haykir
- Institute of Physiology, University of Zürich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Martin Hrabĕ de Angelis
- Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
- Lehrstuhl Für Experimentelle Genetik, Technische Universität München, Freising-Weihenstephan, Germany
- Member of German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Nati Hernando
- Institute of Physiology, University of Zürich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Isabel Rubio-Aliaga
- Institute of Physiology, University of Zürich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Carsten A Wagner
- Institute of Physiology, University of Zürich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland.
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Wagner CA. Renal Intercalated Cell Differentiation and Acid-Base Regulation. J Am Soc Nephrol 2024; 35:519-521. [PMID: 38588503 DOI: 10.1681/asn.0000000000000348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/10/2024] Open
Affiliation(s)
- Carsten A Wagner
- Department of Physiology, University of Zurich, Zürich, Switzerland
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Imenez Silva PH, Pepin M, Figurek A, Gutiérrez-Jiménez E, Bobot M, Iervolino A, Mattace-Raso F, Hoorn EJ, Bailey MA, Hénaut L, Nielsen R, Frische S, Trepiccione F, Hafez G, Altunkaynak HO, Endlich N, Unwin R, Capasso G, Pesic V, Massy Z, Wagner CA, Consortium C. Animal models to study cognitive impairment of chronic kidney disease. Am J Physiol Renal Physiol 2024. [PMID: 38634137 DOI: 10.1152/ajprenal.00338.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 04/04/2024] [Indexed: 04/19/2024] Open
Abstract
Mild cognitive impairment (MCI) is common in people with chronic kidney disease (CKD) and its prevalence increases with progressive loss of kidney function. MCI is characterized by a decline in cognitive performance greater than expected for an individual age and education level but with minimal impairment of instrumental activities of daily living. Deterioration can affect one or several cognitive domains (attention, memory, executive functions, language, and perceptual motor or social cognition). Given the increasing prevalence of kidney disease, more and more people with CKD will also develop MCI causing an enormous disease burden for these individuals, their relatives and society. However, the underlying pathomechanisms are poorly understood and current therapies mostly aim at supporting patients in their daily life. This illustrates the urgent need to elucidate the pathogenesis, and potential therapeutic targets and test novel therapies in appropriate preclinical models. Here, we will outline the necessary criteria for experimental modelling of cognitive disorders in CKD. We discuss the use of mice, rats and zebrafish as model systems and present valuable techniques through which kidney function and cognitive impairment can be assessed in this setting. Our objective is to enable researchers to overcome hurdles and accelerate preclinical research aimed at improving therapy of people with CKD and MCI.
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Affiliation(s)
- Pedro H Imenez Silva
- Division of Nephrology and Transplantation, Erasmus Medical Center, Rotterdam, Netherlands
| | - Marion Pepin
- Departement of Geriatric Medicine, CHU Ambroise Paré, Billancourt Cedex, France
| | - Andreja Figurek
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | | | - Mickaël Bobot
- Centre de Néphrologie et Transplantation Rénale, Hôpital de la Conception, Marseille, France
| | - Anna Iervolino
- Department of Translational Medical Sciences, University of Campania, Naples, Italy
| | - Francesco Mattace-Raso
- Department of Geriatric Medicine, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Ewout J Hoorn
- Internal Medicine, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Matthew A Bailey
- Edinburgh Kidney, Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, United Kingdom
| | - Lucie Hénaut
- UR UPJV 7517, Pathophysiological Mechanisms and Consequences of Cardiovascular Calcifications (MP3CV), Jules Verne University of Picardie, France
| | - Rikke Nielsen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | | | | | - Gaye Hafez
- Department of Pharmacology, Faculty of Pharmacy, Altinbas University, Istanbul, Turkey
| | | | - Nicole Endlich
- Anatomy and Cell Biology, Greifswald University Hospital, Greifswald, MV, Germany
| | - Robert Unwin
- Department of Renal Medicine, University College London, London, United Kingdom
| | | | - Vesna Pesic
- Department of Physiology, Faculty of Pharmacy, University of Belgrade, Serbia
| | - Ziad Massy
- Service de Néphrologie, CHU Ambroise Paré, Assistance Publique - Hôpitaux de Paris & Université Paris-Saclay, University Paris-Saclay, France
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland
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Wagner CA, Silva PHI. The mighty proton. Pflugers Arch 2024; 476:423-425. [PMID: 38460007 DOI: 10.1007/s00424-024-02942-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2024] [Revised: 03/05/2024] [Accepted: 03/05/2024] [Indexed: 03/11/2024]
Affiliation(s)
- Carsten A Wagner
- Department of Physiology, University of Zurich, Zurich, Switzerland.
| | - Pedro H Imenez Silva
- Department of Internal Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, University Medical Center, Rotterdam, The Netherlands.
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Haykir B, Moser SO, Pastor-Arroyo EM, Schnitzbauer U, Radvanyi Z, Prucker I, Qiu D, Fiedler D, Saiardi A, Jessen HJ, Hernando N, Wagner CA. The Ip6k1 and Ip6k2 Kinases Are Critical for Normal Renal Tubular Function. J Am Soc Nephrol 2024; 35:441-455. [PMID: 38317282 PMCID: PMC11000740 DOI: 10.1681/asn.0000000000000303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 12/24/2023] [Indexed: 02/07/2024] Open
Abstract
SIGNIFICANCE STATEMENT Kidneys are gatekeepers of systemic inorganic phosphate balance because they control urinary phosphate excretion. In yeast and plants, inositol hexakisphosphate kinases (IP6Ks) are central to regulate phosphate metabolism, whereas their role in mammalian phosphate homeostasis is mostly unknown. We demonstrate in a renal cell line and in mice that Ip6k1 and Ip6k2 are critical for normal expression and function of the major renal Na + /Pi transporters NaPi-IIa and NaPi-IIc. Moreover, Ip6k1/2-/- mice also show symptoms of more generalized kidney dysfunction. Thus, our results suggest that IP6Ks are essential for phosphate metabolism and proper kidney function in mammals. BACKGROUND Inorganic phosphate is an essential mineral, and its plasma levels are tightly regulated. In mammals, kidneys are critical for maintaining phosphate homeostasis through mechanisms that ultimately regulate the expression of the Na + /Pi cotransporters NaPi-IIa and NaPi-IIc in proximal tubules. Inositol pyrophosphate 5-IP 7 , generated by IP6Ks, is a main regulator of phosphate metabolism in yeast and plants. IP6Ks are conserved in mammals, but their role in phosphate metabolism in vivo remains unexplored. METHODS We used in vitro (opossum kidney cells) and in vivo (renal tubular-specific Ip6k1/2-/- mice) models to analyze the role of IP6K1/2 in phosphate homeostasis in mammals. RESULTS In both systems, Ip6k1 and Ip6k2 are responsible for synthesis of 5-IP 7 . Depletion of Ip6k1/2 in vitro reduced phosphate transport and mRNA expression of Na + /Pi cotransporters, and it blunts phosphate transport adaptation to changes in ambient phosphate. Renal ablation of both kinases in mice also downregulates the expression of NaPi-IIa and NaPi-IIc and lowered the uptake of phosphate into proximal renal brush border membranes. In addition, the absence of Ip6k1 and Ip6k2 reduced the plasma concentration of fibroblast growth factor 23 and increased bone resorption, despite of which homozygous males develop hypophosphatemia. Ip6k1/2-/- mice also show increased diuresis, albuminuria, and hypercalciuria, although the morphology of glomeruli and proximal brush border membrane seemed unaffected. CONCLUSIONS Depletion of renal Ip6k1/2 in mice not only altered phosphate homeostasis but also dysregulated other kidney functions.
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Affiliation(s)
- Betül Haykir
- Switzerland and National Center of Competence in Research NCCR Kidney.CH, Institute of Physiology, University of Zurich, Zürich, Switzerland
| | - Seraina Olivia Moser
- Switzerland and National Center of Competence in Research NCCR Kidney.CH, Institute of Physiology, University of Zurich, Zürich, Switzerland
| | - Eva Maria Pastor-Arroyo
- Switzerland and National Center of Competence in Research NCCR Kidney.CH, Institute of Physiology, University of Zurich, Zürich, Switzerland
| | - Udo Schnitzbauer
- Switzerland and National Center of Competence in Research NCCR Kidney.CH, Institute of Physiology, University of Zurich, Zürich, Switzerland
| | - Zsuzsa Radvanyi
- Switzerland and National Center of Competence in Research NCCR Kidney.CH, Institute of Physiology, University of Zurich, Zürich, Switzerland
| | - Isabel Prucker
- The Center for Integrative Biological Signalling Studies, Institute of Organic Chemistry and CIBSS, University of Freiburg, Freiburg, Germany
| | - Danye Qiu
- The Center for Integrative Biological Signalling Studies, Institute of Organic Chemistry and CIBSS, University of Freiburg, Freiburg, Germany
| | - Dorothea Fiedler
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Berlin, Germany
| | - Adolfo Saiardi
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
| | - Henning J. Jessen
- The Center for Integrative Biological Signalling Studies, Institute of Organic Chemistry and CIBSS, University of Freiburg, Freiburg, Germany
| | - Nati Hernando
- Switzerland and National Center of Competence in Research NCCR Kidney.CH, Institute of Physiology, University of Zurich, Zürich, Switzerland
| | - Carsten A. Wagner
- Switzerland and National Center of Competence in Research NCCR Kidney.CH, Institute of Physiology, University of Zurich, Zürich, Switzerland
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Wagner CA, Rubio Aliaga I, Egli-Spichtig D. Is fibroblast growth factor 23 the main culprit for cardiovascular disease in chronic kidney disease? Am J Physiol Renal Physiol 2024; 326:F561-F562. [PMID: 38205545 DOI: 10.1152/ajprenal.00379.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 01/02/2024] [Indexed: 01/12/2024] Open
Affiliation(s)
- Carsten A Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland
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Wagner CA. The basics of phosphate metabolism. Nephrol Dial Transplant 2024; 39:190-201. [PMID: 37660247 PMCID: PMC10828206 DOI: 10.1093/ndt/gfad188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Indexed: 09/04/2023] Open
Abstract
Phosphorus is an essential mineral that is, in the form of inorganic phosphate (Pi), required for building cell membranes, DNA and RNA molecules, energy metabolism, signal transduction and pH buffering. In bone, Pi is essential for bone stability in the form of apatite. Intestinal absorption of dietary Pi depends on its bioavailability and has two distinct modes of active transcellular and passive paracellular absorption. Active transport is transporter mediated and partly regulated, while passive absorption depends mostly on bioavailability. Renal excretion controls systemic Pi levels, depends on transporters in the proximal tubule and is highly regulated. Deposition and release of Pi into and from soft tissues and bone has to be tightly controlled. The endocrine network coordinating intestinal absorption, renal excretion and bone turnover integrates dietary intake and metabolic requirements with renal excretion and is critical for bone stability and cardiovascular health during states of hypophosphataemia or hyperphosphataemia as evident from inborn or acquired diseases. This review provides an integrated overview of the biology of phosphate and Pi in mammals.
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Affiliation(s)
- Carsten A Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland
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Radvanyi Z, Yoo EJ, Kandasamy P, Salas-Bastos A, Monnerat S, Refardt J, Christ-Crain M, Hayashi H, Kondo Y, Jantsch J, Rubio-Aliaga I, Sommer L, Wagner CA, Hediger MA, Kwon HM, Loffing J, Pathare G. Extracellular sodium regulates fibroblast growth factor 23 (FGF23) formation. J Biol Chem 2024; 300:105480. [PMID: 37992803 PMCID: PMC10770535 DOI: 10.1016/j.jbc.2023.105480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 10/30/2023] [Accepted: 11/16/2023] [Indexed: 11/24/2023] Open
Abstract
The bone-derived hormone fibroblast growth factor-23 (FGF23) has recently received much attention due to its association with chronic kidney disease and cardiovascular disease progression. Extracellular sodium concentration ([Na+]) plays a significant role in bone metabolism. Hyponatremia (lower serum [Na+]) has recently been shown to be independently associated with FGF23 levels in patients with chronic systolic heart failure. However, nothing is known about the direct impact of [Na+] on FGF23 production. Here, we show that an elevated [Na+] (+20 mM) suppressed FGF23 formation, whereas low [Na+] (-20 mM) increased FGF23 synthesis in the osteoblast-like cell lines UMR-106 and MC3T3-E1. Similar bidirectional changes in FGF23 abundance were observed when osmolality was altered by mannitol but not by urea, suggesting a role of tonicity in FGF23 formation. Moreover, these changes in FGF23 were inversely proportional to the expression of NFAT5 (nuclear factor of activated T cells-5), a transcription factor responsible for tonicity-mediated cellular adaptations. Furthermore, arginine vasopressin, which is often responsible for hyponatremia, did not affect FGF23 production. Next, we performed a comprehensive and unbiased RNA-seq analysis of UMR-106 cells exposed to low versus high [Na+], which revealed several novel genes involved in cellular adaptation to altered tonicity. Additional analysis of cells with Crisp-Cas9-mediated NFAT5 deletion indicated that NFAT5 controls numerous genes associated with FGF23 synthesis, thereby confirming its role in [Na+]-mediated FGF23 regulation. In line with these in vitro observations, we found that hyponatremia patients have higher FGF23 levels. Our results suggest that [Na+] is a critical regulator of FGF23 synthesis.
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Affiliation(s)
- Zsuzsa Radvanyi
- Institute of Anatomy, University of Zurich, Zurich, Switzerland; Swiss National Centre of Competence in Research "Kidney Control of Homeostasis", Zurich, Switzerland
| | - Eun Jin Yoo
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Palanivel Kandasamy
- Membrane Transport Discovery Lab, Department of Nephrology and Hypertension and Department of Biomedical Research, Inselspital, University of Bern, Bern, Switzerland
| | | | - Sophie Monnerat
- Department of Endocrinology, Diabetology and Metabolism, University Hospital Basel, Basel, Switzerland; Department of Clinical Research, University of Basel, Basel, Switzerland
| | - Julie Refardt
- Department of Endocrinology, Diabetology and Metabolism, University Hospital Basel, Basel, Switzerland; Department of Clinical Research, University of Basel, Basel, Switzerland
| | - Mirjam Christ-Crain
- Department of Endocrinology, Diabetology and Metabolism, University Hospital Basel, Basel, Switzerland; Department of Clinical Research, University of Basel, Basel, Switzerland
| | - Himeka Hayashi
- Department of Animal Sciences, Teikyo University of Science, Yamanashi, Japan
| | - Yasuhiko Kondo
- Department of Animal Sciences, Teikyo University of Science, Yamanashi, Japan
| | - Jonathan Jantsch
- Institute of Clinical Microbiology and Hygiene, University Hospital of Regensburg and University of Regensburg, Regensburg, Germany; Institute for Medical Microbiology, Immunology, and Hygiene, and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Isabel Rubio-Aliaga
- Swiss National Centre of Competence in Research "Kidney Control of Homeostasis", Zurich, Switzerland; Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Lukas Sommer
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Carsten A Wagner
- Swiss National Centre of Competence in Research "Kidney Control of Homeostasis", Zurich, Switzerland; Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Matthias A Hediger
- Membrane Transport Discovery Lab, Department of Nephrology and Hypertension and Department of Biomedical Research, Inselspital, University of Bern, Bern, Switzerland
| | - Hyug Moo Kwon
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Johannes Loffing
- Institute of Anatomy, University of Zurich, Zurich, Switzerland; Swiss National Centre of Competence in Research "Kidney Control of Homeostasis", Zurich, Switzerland
| | - Ganesh Pathare
- Institute of Anatomy, University of Zurich, Zurich, Switzerland; Swiss National Centre of Competence in Research "Kidney Control of Homeostasis", Zurich, Switzerland.
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Rodríguez D, Gurevich E, Mohammadi Jouabadi S, Pastor Arroyo EM, Ritter A, Estoppey Younes S, Wagner CA, Imenez Silva PH, Seeger H, Mohebbi N. Serum sclerostin is associated with recurrent kidney stone formation independent of hypercalciuria. Clin Kidney J 2024; 17:sfad256. [PMID: 38186870 PMCID: PMC10768761 DOI: 10.1093/ckj/sfad256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Indexed: 01/09/2024] Open
Abstract
Background Kidney stones are frequent in industrialized countries with a lifetime risk of 10 to 15%. A high percentage of individuals experience recurrence. Calcium-containing stones account for more than 80% of kidney stones. Diet, environmental factors, behavior, and genetic variants contribute to the development of kidney stones. Osteocytes excrete the 21 kDa glycoprotein sclerostin, which inhibits bone formation by osteoblasts. Animal data suggests that sclerostin might directly or indirectly regulate calcium excretion via the kidney. As hypercalciuria is one of the most relevant risk factors for kidney stones, sclerostin might possess pathogenic relevance in nephrolithiasis. Methods We performed a prospective cross-sectional observational controlled study in 150 recurrent kidney stone formers (rKSF) to analyse the association of sclerostin with known stone risk factors and important modulators of calcium-phosphate metabolism. Serum sclerostin levels were determined at the first visit. As controls, we used 388 non-stone formers from a large Swiss epidemiological cohort. Results Sclerostin was mildly increased in rKSF in comparison to controls. This finding was more pronounced in women compared to men. Logistic regression indicated an association of serum sclerostin with rKSF status. In hypercalciuric individuals, sclerostin levels were not different from normocalciuric patients. In Spearman correlation analysis we found a positive correlation between sclerostin, age, and BMI and a negative correlation with eGFR. There was a weak correlation with iPTH and intact FGF 23. In contrast, serum sclerostin levels were not associated with 25-OH Vitamin D3, 1,25-dihydroxy-Vitamin D3, urinary calcium and phosphate or other urinary lithogenic risk factors. Conclusion This is the first prospective controlled study investigating serum sclerostin in rKSF. Sclerostin levels were increased in rKSF independent of hypercalciuria and significantly associated with the status as rKSF. It appears that mechanisms other than hypercalciuria may be involved and thus further studies are required to elucidate underlying pathways.
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Affiliation(s)
- Daniel Rodríguez
- Division of Nephrology, University Hospital Zurich, Zurich, Switzerland
| | | | - Soroush Mohammadi Jouabadi
- Department of Internal Medicine , Division of Vascular Medicine and Pharmacology, Erasmus Medical Center, University Medical Center Rotterdam, the Netherlands
| | | | - Alexander Ritter
- Division of Nephrology, University Hospital Zurich, Zurich, Switzerland
| | | | - Carsten A Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Pedro Henrique Imenez Silva
- Department of Internal Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, University Medical Center Rotterdam, the Netherlands
| | - Harald Seeger
- Division of Nephrology, University Hospital Zurich, Zurich, Switzerland
- Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Nilufar Mohebbi
- Division of Nephrology, University Hospital Zurich, Zurich, Switzerland
- Institute of Physiology, University of Zurich, Zurich, Switzerland
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Bourgeois S, Kovacikova J, Bugarski M, Bettoni C, Gehring N, Hall A, Wagner CA. The B1 H + -ATPase ( Atp6v1b1 ) Subunit in Non-Type A Intercalated Cells is Required for Driving Pendrin Activity and the Renal Defense Against Alkalosis. J Am Soc Nephrol 2024; 35:7-21. [PMID: 37990364 PMCID: PMC10786613 DOI: 10.1681/asn.0000000000000259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 10/07/2023] [Indexed: 11/23/2023] Open
Abstract
SIGNIFICANCE STATEMENT In the kidney, the B1 H + -ATPase subunit is mostly expressed in intercalated cells (IC). Its importance in acid-secreting type A ICs is evident in patients with inborn distal renal tubular acidosis and ATP6V1B1 mutations. However, the protein is also highly expressed in alkali-secreting non-type A ICs where its function is incompletely understood. We demonstrate in Atp6v1b1 knock out mice that the B1 subunit is critical for the renal response to defend against alkalosis during an alkali load or chronic furosemide treatment. These findings highlight the importance of non-type A ICs in maintaining acid-base balance in response to metabolic challenges or commonly used diuretics. BACKGROUND Non-type A ICs in the collecting duct system express the luminal Cl - /HCO 3- exchanger pendrin and apical and/or basolateral H + -ATPases containing the B1 subunit isoform. Non-type A ICs excrete bicarbonate during metabolic alkalosis. Mutations in the B1 subunit (ATP6V1B1) cause distal renal tubular acidosis due to its role in acid secretory type A ICs. The function of B1 in non-type A ICs has remained elusive. METHODS We examined the responses of Atp6v1b1-/- and Atp6v1b1+/+ mice to an alkali load and to chronic treatment with furosemide. RESULTS An alkali load or 1 week of furosemide resulted in a more pronounced hypokalemic alkalosis in male ATP6v1b1-/- versus Atp6v1b1+/+ mice that could not be compensated by respiration. Total pendrin expression and activity in non-type A ICs of ex vivo microperfused cortical collecting ducts were reduced, and β2 -adrenergic stimulation of pendrin activity was blunted in ATP6v1b1-/- mice. Basolateral H + -ATPase activity was strongly reduced, although the basolateral expression of the B2 isoform was increased. Ligation assays for H + -ATPase subunits indicated impaired assembly of V 0 and V 1 H + -ATPase domains. During chronic furosemide treatment, ATP6v1b1-/- mice also showed polyuria and hyperchloremia versus Atp6v1b1+/+ . The expression of pendrin, the water channel AQP2, and subunits of the epithelial sodium channel ENaC were reduced. CONCLUSIONS Our data demonstrate a critical role of H + -ATPases in non-type A ICs function protecting against alkalosis and reveal a hitherto unrecognized need of basolateral B1 isoform for a proper H + -ATPase complexes assembly and ability to be stimulated.
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Affiliation(s)
- Soline Bourgeois
- Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Jana Kovacikova
- Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Milica Bugarski
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Carla Bettoni
- Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Nicole Gehring
- Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Andrew Hall
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
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Wagner CA. Pharmacology of Mammalian Na +-Dependent Transporters of Inorganic Phosphate. Handb Exp Pharmacol 2024; 283:285-317. [PMID: 36592227 DOI: 10.1007/164_2022_633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Inorganic phosphate (Pi) is an essential component of many biologically important molecules such as DNA, RNA, ATP, phospholipids, or apatite. It is required for intracellular phosphorylation signaling events and acts as pH buffer in intra- and extracellular compartments. Intestinal absorption, uptake into cells, and renal reabsorption depend on a set of different phosphate transporters from the SLC20 (PiT transporters) and SLC34 (NaPi transporters) gene families. The physiological relevance of these transporters is evident from rare monogenic disorders in humans affecting SLC20A2 (Fahr's disease, basal ganglia calcification), SLC34A1 (idiopathic infantile hypercalcemia), SLC34A2 (pulmonary alveolar microlithiasis), and SLC34A3 (hereditary hypophosphatemic rickets with hypercalciuria). SLC34 transporters are inhibited by millimolar concentrations of phosphonoformic acid or arsenate while SLC20 are relatively resistant to these compounds. More recently, a series of more specific and potent drugs have been developed to target SLC34A2 to reduce intestinal Pi absorption and to inhibit SLC34A1 and/or SLC34A3 to increase renal Pi excretion in patients with renal disease and incipient hyperphosphatemia. Also, SLC20 inhibitors have been developed with the same intention. Some of these substances are currently undergoing preclinical and clinical testing. Tenapanor, a non-absorbable Na+/H+-exchanger isoform 3 inhibitor, reduces intestinal Pi absorption likely by indirectly acting on the paracellular pathway for Pi and has been tested in several phase III trials for reducing Pi overload in patients with renal insufficiency and dialysis.
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Affiliation(s)
- Carsten A Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland.
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12
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Liabeuf S, Pešić V, Spasovski G, Maciulaitis R, Bobot M, Farinha A, Wagner CA, Unwin RJ, Capasso G, Bumblyte IA, Hafez G. Drugs with a negative impact on cognitive function (Part 1): chronic kidney disease as a risk factor. Clin Kidney J 2023; 16:2365-2377. [PMID: 38045996 PMCID: PMC10689135 DOI: 10.1093/ckj/sfad241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Indexed: 12/05/2023] Open
Abstract
People living with chronic kidney disease (CKD) frequently suffer from mild cognitive impairment and/or other neurocognitive disorders. This review in two parts will focus on adverse drug reactions resulting in cognitive impairment as a potentially modifiable risk factor in CKD patients. Many patients with CKD have a substantial burden of comorbidities leading to polypharmacy. A recent study found that patients seen by nephrologists were the most complex to treat because of their high number of comorbidities and medications. Due to polypharmacy, these patients may experience a wide range of adverse drug reactions. Along with CKD progression, the accumulation of uremic toxins may lead to blood-brain barrier (BBB) disruption and pharmacokinetic alterations, increasing the risk of adverse reactions affecting the central nervous system (CNS). In patients on dialysis, the excretion of drugs that depend on kidney function is severely reduced such that adverse and toxic levels of a drug or its metabolites may be reached at relatively low doses, unless dosing is adjusted. This first review will discuss how CKD represents a risk factor for adverse drug reactions affecting the CNS via (i) BBB disruption associated with CKD and (ii) the impact of reduced kidney function and dialysis itself on drug pharmacokinetics.
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Affiliation(s)
- Sophie Liabeuf
- Pharmacoepidemiology Unit, Department of Clinical Pharmacology, Amiens University Medical Center, Amiens, France
- MP3CV Laboratory, EA7517, Jules Verne University of Picardie, Amiens, France
| | - Vesna Pešić
- Faculty of Pharmacy, University of Belgrade, Belgrade, Serbia
| | - Goce Spasovski
- Department of Nephrology, Clinical Centre “Mother Theresa”, Saints Cyril and Methodius University, Skopje, North Macedonia
| | - Romaldas Maciulaitis
- Department of Nephrology, Lithuanian University of Health Sciences, Kaunas, Lithuania
- Institute of Physiology and Pharmacology, Faculty of Medicines, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Mickaël Bobot
- Aix-Marseille University, Department of Nephrology, AP-HM, La Conception Hospital, Marseille, France; C2VN Laboratory, Inserm 1263, INRAE 1260, Aix-Marseille University, Marseille, France
| | - Ana Farinha
- Department of Nephrology, Hospital de Vila Franca de Xira, Lisbon, Portugal
| | - Carsten A Wagner
- Institute of Physiology, University of Zürich, Zurich, Switzerland
| | - Robert J Unwin
- Department of Renal Medicine, Royal Free Hospital, University College London, London, UK
| | - Giovambattista Capasso
- Department of Translantional Medical Sciences, University of Campania Luigi Vanvitelli , Naples, Italy
- Biogem Research Institute , Ariano Irpino, Italy
| | - Inga Arune Bumblyte
- Department of Nephrology, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Gaye Hafez
- Department of Pharmacology, Faculty of Pharmacy, Altinbas University, Istanbul, Turkey
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13
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Egli-Spichtig D, Hamid AK, Arroyo EMP, Ketteler M, Wiecek A, Rosenkranz AR, Pasch A, Lorenz H, Hellmann B, Karus M, Ammer R, Rubio-Aliaga I, Wagner CA. Intact FGF23 predicts serum phosphate improvement after combined nicotinamide and phosphate binder treatment in hemodialysis patients. Clin Kidney J 2023; 16:1622-1633. [PMID: 37779856 PMCID: PMC10539220 DOI: 10.1093/ckj/sfad040] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Indexed: 10/03/2023] Open
Abstract
Background Hyperphosphatemia is associated with increased mortality and cardiovascular morbidity of end-stage kidney failure (ESKF) patients. Managing serum phosphate in ESKF patients is challenging and mostly based on limiting intestinal phosphate absorption with low phosphate diets and phosphate binders (PB). In a multi-centric, double-blinded, placebo-controlled study cohort of maintenance hemodialysis patients with hyperphosphatemia, we demonstrated the efficacy of nicotinamide modified release (NAMR) formulation treatment in addition to standard PB therapy in decreasing serum phosphate. Here we aimed to assess the relationship between phosphate, FGF23, inflammation and iron metabolism in this cohort. Methods We measured the plasma concentrations of intact fibroblast growth factor 23 (iFGF23) and selected proinflammatory cytokines at baseline and Week 12 after initiating treatment. Results We observed a strong correlation between iFGF23 and cFGF23 (C-terminal fragment plus iFGF23). We identified iFGF23 as a better predictor of changes in serum phosphate induced by NAMR and PB treatment compared with cFGF23. Recursive partitioning revealed at baseline and Week 12, that iFGF23 and cFGF23 together with T50 propensity were the most important predictors of serum phosphate, whereas intact parathyroid hormone (iPTH) played a minor role in this model. Furthermore, we found serum phosphate and iPTH as the best predictors of iFGF23 and cFGF23. Sex, age, body mass index, and markers of inflammation and iron metabolism had only a minor impact in predicting FGF23. Conclusion Lowering serum phosphate in ESKF patients may depend highly on iFGF23 which is correlated to cFGF23 levels. Serum phosphate was the most important predictor of plasma FGF23 in this ESKF cohort.
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Affiliation(s)
- Daniela Egli-Spichtig
- Institute of Physiology, University of Zurich, 8057 Zurich, Switzerland, and National Center of Competence in Research NCCR Kidney.CH
| | - Ahmad Kamal Hamid
- Institute of Physiology, University of Zurich, 8057 Zurich, Switzerland, and National Center of Competence in Research NCCR Kidney.CH
| | - Eva Maria Pastor Arroyo
- Institute of Physiology, University of Zurich, 8057 Zurich, Switzerland, and National Center of Competence in Research NCCR Kidney.CH
| | - Markus Ketteler
- Robert Bosch Hospital, Department of General Internal Medicine and Nephrology, Stuttgart, Germany
| | - Andrzej Wiecek
- Department of Nephrology, Transplantation and Internal Medicine, Medical University of Silesia, Katowice, Poland
| | - Alexander R Rosenkranz
- Division of Nephrology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Andreas Pasch
- Calciscon AG, 2503 Biel, Switzerland
- Department of Nephrology, Lindenhofspital, 3012 Bern, Switzerland
- Department of Physiology and Pathophysiology, Johannes Kepler University Linz, Linz, Austria
| | - Horst Lorenz
- Buero fuer Biometrie und Statistik, Neuberg, Germany
| | | | - Michael Karus
- MEDICE Arzneimittel Pütter GmbH & Co KG, Iserlohn, Germany
| | - Richard Ammer
- MEDICE Arzneimittel Pütter GmbH & Co KG, Iserlohn, Germany
- Department of Medicine D, Division of General Internal Medicine, Nephrology and Rheumatology, University Hospital of Münster, Münster, Germany
| | - Isabel Rubio-Aliaga
- Institute of Physiology, University of Zurich, 8057 Zurich, Switzerland, and National Center of Competence in Research NCCR Kidney.CH
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich, 8057 Zurich, Switzerland, and National Center of Competence in Research NCCR Kidney.CH
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14
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Fuente R, Pastor-Arroyo EM, Gehring N, Oro Carbajosa P, Alonso-Durán L, Zderic I, Tapia-Dean J, Hamid AK, Bettoni C, Santos F, Wagner CA, Rubio-Aliaga I. Blocking FGF23 signaling improves the growth plate of mice with X-linked hypophosphatemia. J Endocrinol 2023; 259:e230025. [PMID: 37439399 DOI: 10.1530/joe-23-0025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 07/12/2023] [Indexed: 07/14/2023]
Abstract
Fibroblast growth factor 23 (FGF23) is a phosphaturic hormone. X-linked hypophosphatemia (XLH) is the most prevalent inherited phosphate wasting disorder due to mutations in the PHEX gene, which cause elevated circulating FGF23 levels. Clinically, it is characterized by growth impairment and defective mineralization of bones and teeth. Treatment of XLH is challenging. Since 2018, neutralizing antibodies against FGF23 have dramatically improved the therapy of XLH patients, although not all patients fully respond to the treatment, and it is very costly. C-terminal fragments of FGF23 have recently emerged as blockers of intact FGF23 signaling. Here, we analyzed the effect on growth and bone of a short 26 residues long C-terminal FGF23 (cFGF23) fragment and two N-acetylated and C-amidated cFGF23 peptides using young XLH mice (Phex C733RMhda mice). Although no major changes in blood parameters were observed after 7 days of treatment with these peptides, bone length and growth plate structure improved. The modified peptides accelerated the growth rate probably by improving growth plate structure and dynamics. The processes of chondrocyte proliferation, death, hypertrophy, and the cartilaginous composition in the growth plate were partially improved in young treated XLH mice. In conclusion, these findings contribute to understand the role of FGF23 signaling in growth plate metabolism and show that this may occur despite continuous hypophosphatemia.
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Affiliation(s)
- Rocío Fuente
- Institute of Physiology, University of Zurich, and National Center of Competence in Research NNCR Kidney, Zurich, CH, Switzerland
- Division of Pediatrics, University of Oviedo, Oviedo, Spain
- Department of Pediatrics, Hospital Universitario Central, Oviedo, Spain
| | - Eva-Maria Pastor-Arroyo
- Institute of Physiology, University of Zurich, and National Center of Competence in Research NNCR Kidney, Zurich, CH, Switzerland
| | - Nicole Gehring
- Institute of Physiology, University of Zurich, and National Center of Competence in Research NNCR Kidney, Zurich, CH, Switzerland
| | | | | | - Ivan Zderic
- AO Research Institute Davos, AO Foundation, Clavadelerstrasse, Davos Platz, Switzerland
| | - James Tapia-Dean
- Department of Pediatrics, Hospital Universitario Central, Oviedo, Spain
| | - Ahmad Kamal Hamid
- Institute of Physiology, University of Zurich, and National Center of Competence in Research NNCR Kidney, Zurich, CH, Switzerland
| | - Carla Bettoni
- Institute of Physiology, University of Zurich, and National Center of Competence in Research NNCR Kidney, Zurich, CH, Switzerland
| | - Fernando Santos
- Division of Pediatrics, University of Oviedo, Oviedo, Spain
- Department of Pediatrics, Hospital Universitario Central, Oviedo, Spain
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich, and National Center of Competence in Research NNCR Kidney, Zurich, CH, Switzerland
| | - Isabel Rubio-Aliaga
- Institute of Physiology, University of Zurich, and National Center of Competence in Research NNCR Kidney, Zurich, CH, Switzerland
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15
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Yassini N, Sprenger J, Pastor Arroyo EM, Krudewig C, Pellegrini G, Joller N, Wagner CA, Imenez Silva PH. Ovarian cancer G protein-coupled receptor 1 (OGR1) deficiency exacerbates crystal deposition and kidney injury in oxalate nephropathy in female mice. Clin Sci (Lond) 2023:CS20230421. [PMID: 37431800 DOI: 10.1042/cs20230421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 06/23/2023] [Accepted: 07/10/2023] [Indexed: 07/12/2023]
Abstract
OGR1 (Gpr68) and GPR4 (Gpr4) are proton-activated G protein-coupled receptors that are stimulated upon increased extracellular acidity. These receptors have various physiological and pathophysiological roles in renal acid-base physiology, tissue inflammation, and fibrosis among others. Their function in injured renal tissue, however, remains mostly unclear. To address this, we investigated their role in crystalline nephropathy by increasing the oxalate intake of GPR4 KO and OGR1 KO mice.  After 10 days of high-oxalate intake and 4 days of recovery, renal crystal content, histopathology, filtration function, and inflammation were assessed. While GPR4 deficiency did not show major alterations in disease progression, OGR1 KO mice had higher urinary calcium levels and exacerbated crystal accumulation accompanied by decreased creatinine clearance and urea excretion and a decreased presence of regulatory T (Treg) cells in kidney tissue. When lowering the severity of the kidney injury, OGR1 KO mice were more prone to develop crystalline nephropathy. In this setting, OGR1 KO mice displayed an increased activation of the immune system and a higher production of pro-inflammatory cytokines by T cells and macrophages.</p> Taken together, in the acute setting of oxalate-induced nephropathy, the lack of the proton-activated GPCR GPR4 does not influence disease. OGR1 deficiency, however, increases crystal deposition leading to impaired kidney function. Thus, OGR1 may be important to limit kidney crystal deposition, which might subsequently be relevant for the pathophysiology of oxalate kidney stones or other crystallopathies.
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Affiliation(s)
| | | | | | | | | | | | - Carsten A Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland, Zurich, Switzerland
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16
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Münch J, Goodyer PR, Wagner CA. Tubular Diseases and Stones Seen From Pediatric and Adult Nephrology Perspectives. Semin Nephrol 2023; 43:151437. [PMID: 37968178 DOI: 10.1016/j.semnephrol.2023.151437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2023]
Abstract
The tubular system of the kidneys is a complex series of morphologic and functional units orchestrating the content of tubular fluid as it flows along the nephron and collecting ducts. Renal tubules maintain body water, regulate electrolytes and acid-base balance, reabsorb precious organic solutes, and eliminate specific metabolites, toxins, and drugs. In addition, decisive mechanisms to adjust blood pressure are governed by the renal tubules. Genetic as well as acquired disorders of these tubular functions may cause serious diseases that manifest both in childhood and adulthood. This article addresses a selection of tubulopathies and the underlying pathomechanisms, while highlighting the important differences in pediatric and adult nephrology care. These range from rare monogenic conditions such as nephrogenic diabetes insipidus, cystinosis, and Bartter syndrome that present in childhood, to the genetic and acquired tubular pathologies causing hypertension or nephrolithiasis that are more prevalent in adults. Both pediatric and adult nephrologists must be aware of these conditions and the age-dependent manifestations that warrant close interaction between the two subspecialties.
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Affiliation(s)
- Johannes Münch
- Institute of Physiology, University of Zurich, Zurich, Switzerland; Institute of Human Genetics, University of Zurich, Zurich, Switzerland; National Center of Competence in Research, NCCR Kidney.CH, Switzerland
| | - Paul R Goodyer
- McGill University Health Centre, Montreal, Quebec, Canada
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland; National Center of Competence in Research, NCCR Kidney.CH, Switzerland.
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17
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Verissimo T, Dalga D, Arnoux G, Sakhi I, Faivre A, Auwerx H, Bourgeois S, Paolucci D, Gex Q, Rutkowski JM, Legouis D, Wagner CA, Hall AM, de Seigneux S. PCK1 is a key regulator of metabolic and mitochondrial functions in renal tubular cells. Am J Physiol Renal Physiol 2023; 324:F532-F543. [PMID: 37102687 PMCID: PMC10202477 DOI: 10.1152/ajprenal.00038.2023] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 03/28/2023] [Accepted: 04/12/2023] [Indexed: 04/28/2023] Open
Abstract
Phosphoenolpyruvate carboxykinase 1 (PCK1 or PEPCK-C) is a cytosolic enzyme converting oxaloacetate to phosphoenolpyruvate, with a potential role in gluconeogenesis, ammoniagenesis, and cataplerosis in the liver. Kidney proximal tubule cells display high expression of this enzyme, whose importance is currently not well defined. We generated PCK1 kidney-specific knockout and knockin mice under the tubular cell-specific PAX8 promoter. We studied the effect of PCK1 deletion and overexpression at the renal level on tubular physiology under normal conditions and during metabolic acidosis and proteinuric renal disease. PCK1 deletion led to hyperchloremic metabolic acidosis characterized by reduced but not abolished ammoniagenesis. PCK1 deletion also resulted in glycosuria, lactaturia, and altered systemic glucose and lactate metabolism at baseline and during metabolic acidosis. Metabolic acidosis resulted in kidney injury in PCK1-deficient animals with decreased creatinine clearance and albuminuria. PCK1 further regulated energy production by the proximal tubule, and PCK1 deletion decreased ATP generation. In proteinuric chronic kidney disease, mitigation of PCK1 downregulation led to better renal function preservation. PCK1 is essential for kidney tubular cell acid-base control, mitochondrial function, and glucose/lactate homeostasis. Loss of PCK1 increases tubular injury during acidosis. Mitigating kidney tubular PCK1 downregulation during proteinuric renal disease improves renal function.NEW & NOTEWORTHY Phosphoenolpyruvate carboxykinase 1 (PCK1) is highly expressed in the proximal tubule. We show here that this enzyme is crucial for the maintenance of normal tubular physiology, lactate, and glucose homeostasis. PCK1 is a regulator of acid-base balance and ammoniagenesis. Preventing PCK1 downregulation during renal injury improves renal function, rendering it an important target during renal disease.
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Affiliation(s)
- Thomas Verissimo
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
- Department of Medicine, Service of Nephrology, Geneva University Hospitals, Geneva, Switzerland
| | - Delal Dalga
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
- Department of Medicine, Service of Nephrology, Geneva University Hospitals, Geneva, Switzerland
| | - Grégoire Arnoux
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - Imene Sakhi
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Anna Faivre
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - Hannah Auwerx
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - Soline Bourgeois
- Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Deborah Paolucci
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - Quentin Gex
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | | | - David Legouis
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
- Division of Intensive Care, Department of Acute Medicine, Geneva University Hospitals, Geneva, Switzerland
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Andrew M Hall
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
- Department of Nephrology, University Hospital Zurich, Zurich, Switzerland
| | - Sophie de Seigneux
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
- Department of Medicine, Service of Nephrology, Geneva University Hospitals, Geneva, Switzerland
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18
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Vitzthum H, Koch M, Eckermann L, Svendsen SL, Berg P, Hübner CA, Wagner CA, Leipziger J, Meyer-Schwesinger C, Ehmke H. The AE4 transporter mediates kidney acid-base sensing. Nat Commun 2023; 14:3051. [PMID: 37236964 DOI: 10.1038/s41467-023-38562-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Accepted: 05/05/2023] [Indexed: 05/28/2023] Open
Abstract
The kidney plays a key role in the correction of systemic acid-base imbalances. Central for this regulation are the intercalated cells in the distal nephron, which secrete acid or base into the urine. How these cells sense acid-base disturbances is a long-standing question. Intercalated cells exclusively express the Na+-dependent Cl-/HCO3- exchanger AE4 (Slc4a9). Here we show that AE4-deficient mice exhibit a major dysregulation of acid-base balance. By combining molecular, imaging, biochemical and integrative approaches, we demonstrate that AE4-deficient mice are unable to sense and appropriately correct metabolic alkalosis and acidosis. Mechanistically, a lack of adaptive base secretion via the Cl-/HCO3- exchanger pendrin (Slc26a4) is the key cellular cause of this derailment. Our findings identify AE4 as an essential part of the renal sensing mechanism for changes in acid-base status.
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Affiliation(s)
- H Vitzthum
- Center for Experimental Medicine, Institute of Cellular and Integrative Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - M Koch
- Center for Experimental Medicine, Institute of Cellular and Integrative Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - L Eckermann
- Center for Experimental Medicine, Institute of Cellular and Integrative Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - S L Svendsen
- Department of Biomedicine, Physiology, Health, Aarhus University, Aarhus, Denmark
| | - P Berg
- Department of Biomedicine, Physiology, Health, Aarhus University, Aarhus, Denmark
| | - C A Hübner
- Institute of Human Genetics, University Hospital Jena, Friedrich Schiller University, Jena, Germany
| | - C A Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland
- National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland
| | - J Leipziger
- Department of Biomedicine, Physiology, Health, Aarhus University, Aarhus, Denmark
| | - C Meyer-Schwesinger
- Center for Experimental Medicine, Institute of Cellular and Integrative Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - H Ehmke
- Center for Experimental Medicine, Institute of Cellular and Integrative Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
- German Center for Cardiovascular Research, Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany.
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19
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Legay C, Haeusermann T, Pasquier J, Chatelan A, Fuster DG, Dhayat N, Seeger H, Ritter A, Mohebbi N, Ernandez T, Stoermann C, Buchkremer F, Segerer S, Wuerzner G, Ammor N, Roth B, Wagner CA, Bonny O, Bochud M. Differences in the food consumption between kidney stone formers and non-formers in the Swiss Kidney Stone Cohort. J Ren Nutr 2023:S1051-2276(23)00067-5. [PMID: 37120128 DOI: 10.1053/j.jrn.2023.04.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Revised: 04/09/2023] [Accepted: 04/16/2023] [Indexed: 05/01/2023] Open
Abstract
OBJECTIVE Diet has a major influence on the formation and management of kidney stones. However, kidney stone formers' diet is difficult to capture in a large population. Our objective was to describe the dietary intake of kidney stone formers in Switzerland and to compare it to non-stone formers. METHODS We used data from the Swiss Kidney Stone Cohort (n=261), a multicentric cohort of recurrent or incident kidney stone formers with additional risk factors, and a control group of CT-scan proven non-stone formers (n=197). Dieticians conducted two consecutive 24-h dietary recalls, using structured interviews and validated software (GloboDiet). We took the mean consumption per participant of the two 24-h dietary recalls to describe the dietary intake and used two-part models to compare the two groups. RESULTS The dietary intake was overall similar between stone and non-stone formers. However, we identified that kidney stone formers had a higher probability of consuming cakes and biscuits (odds ratio, OR[95% CI] =1.56[1.03; 2.37]) and soft drinks (OR=1.66[1.08; 2.55]). Kidney stone formers had a lower probability of consuming nuts and seeds (OR =0.53[0.35; 0.82]), fresh cheese (OR=0.54[0.30; 0.96]), teas (OR=0.50[0.3; 0.84]), and alcoholic beverages (OR=0.35[0.23; 0.54]), especially wine (OR=0.42[0.27; 0.65]). Furthermore, among consumers, stone formers reported smaller quantities of vegetables (β coeff[95% CI]= - 0.23[- 0.41; - 0.06]), coffee (β coeff= - 0.21[- 0.37; - 0.05]), teas (β coeff= - 0.52[- 0.92; - 0.11]) and alcoholic beverages (β coeff= - 0.34[- 0.63; - 0.06]). CONCLUSION Stone formers reported lower intakes of vegetables, tea, coffee, and alcoholic beverages, more specifically wine, but reported drinking more frequently soft drinks than non-stone formers. For the other food groups, stone formers and non-formers reported similar dietary intakes. Further research is needed to better understand the links between diet and kidney stone formation and develop dietary recommendations adapted to the local settings and cultural habits.
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Affiliation(s)
- Constance Legay
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland; Center for Primary Care and Public Health (Unisanté), Department of Epidemiology and Health Systems, University of Lausanne, Lausanne, Switzerland; National Center of Competence in Research NCCR Kidney.CH
| | | | - Jérôme Pasquier
- Center for Primary Care and Public Health (Unisanté), Department Formation, Research and Innovation, University of Lausanne, Lausanne, Switzerland
| | - Angeline Chatelan
- Department of Nutrition and Dietetics, Geneva School of Health Sciences, HES-SO University of Applied Sciences and Arts Western, Geneva, Switzerland; Institute of Social and Preventive Medicine (ISPM), University of Bern, Bern, Switzerland
| | - Daniel G Fuster
- National Center of Competence in Research NCCR Kidney.CH; Department of Nephrology and Hypertension, Inselspital, Bern University Hospital, University of Bern, Switzerland
| | - Nasser Dhayat
- Department of Nephrology and Hypertension, Inselspital, Bern University Hospital, University of Bern, Switzerland
| | - Harald Seeger
- Division of Nephrology, University Hospital Zurich, Zurich, Switzerland
| | - Alexander Ritter
- Division of Nephrology, University Hospital Zurich, Zurich, Switzerland
| | - Nilufar Mohebbi
- Division of Nephrology, University Hospital Zurich, Zurich, Switzerland
| | - Thomas Ernandez
- Service of Nephrology, Geneva University Hospitals, Geneva, Switzerland
| | | | - Florian Buchkremer
- Nephrologie, Dialyse und Transplantation, Kantonsspital Aarau, Aarau, Switzerland
| | - Stephan Segerer
- Nephrologie, Dialyse und Transplantation, Kantonsspital Aarau, Aarau, Switzerland
| | - Grégoire Wuerzner
- Service of Nephrology and Hypertension, Lausanne University Hospital, Lausanne, Switzerland
| | - Nadia Ammor
- Service of Nephrology and Hypertension, Lausanne University Hospital, Lausanne, Switzerland
| | - Beat Roth
- Department of Urology, Lausanne University Hospital, CHUV, University of Lausanne, Switzerland
| | - Carsten A Wagner
- National Center of Competence in Research NCCR Kidney.CH; Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Olivier Bonny
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland; National Center of Competence in Research NCCR Kidney.CH; Service of Nephrology and Hypertension, Lausanne University Hospital, Lausanne, Switzerland; Service of Nephrology, Fribourg State Hospital, Fribourg, Switzerland.
| | - Murielle Bochud
- Center for Primary Care and Public Health (Unisanté), Department of Epidemiology and Health Systems, University of Lausanne, Lausanne, Switzerland; National Center of Competence in Research NCCR Kidney.CH
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20
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Wagner CA, Unwin R, Lopez-Garcia SC, Kleta R, Bockenhauer D, Walsh S. The pathophysiology of distal renal tubular acidosis. Nat Rev Nephrol 2023; 19:384-400. [PMID: 37016093 DOI: 10.1038/s41581-023-00699-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/27/2023] [Indexed: 04/06/2023]
Abstract
The kidneys have a central role in the control of acid-base homeostasis owing to bicarbonate reabsorption and production of ammonia and ammonium in the proximal tubule and active acid secretion along the collecting duct. Impaired acid excretion by the collecting duct system causes distal renal tubular acidosis (dRTA), which is characterized by the failure to acidify urine below pH 5.5. This defect originates from reduced function of acid-secretory type A intercalated cells. Inherited forms of dRTA are caused by variants in SLC4A1, ATP6V1B1, ATP6V0A4, FOXI1, WDR72 and probably in other genes that are yet to be discovered. Inheritance of dRTA follows autosomal-dominant and -recessive patterns. Acquired forms of dRTA are caused by various types of autoimmune diseases or adverse effects of some drugs. Incomplete dRTA is frequently found in patients with and without kidney stone disease. These patients fail to appropriately acidify their urine when challenged, suggesting that incomplete dRTA may represent an intermediate state in the spectrum of the ability to excrete acids. Unrecognized or insufficiently treated dRTA can cause rickets and failure to thrive in children, osteomalacia in adults, nephrolithiasis and nephrocalcinosis. Electrolyte disorders are also often present and poorly controlled dRTA can increase the risk of developing chronic kidney disease.
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Affiliation(s)
- Carsten A Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland.
- Department of Renal Medicine, Royal Free Hospital, University College London, London, UK.
| | - Robert Unwin
- Department of Renal Medicine, Royal Free Hospital, University College London, London, UK
| | - Sergio C Lopez-Garcia
- Department of Renal Medicine, Royal Free Hospital, University College London, London, UK
- Department of Paediatric Nephrology, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK
| | - Robert Kleta
- Department of Renal Medicine, Royal Free Hospital, University College London, London, UK
| | - Detlef Bockenhauer
- Department of Renal Medicine, Royal Free Hospital, University College London, London, UK
- Department of Paediatric Nephrology, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK
| | - Stephen Walsh
- Department of Renal Medicine, Royal Free Hospital, University College London, London, UK
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21
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Wagner CA. Smart kidneys: Enhance intratubular communication to overcome disease. Acta Physiol (Oxf) 2023; 237:e13930. [PMID: 36622268 DOI: 10.1111/apha.13930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 01/02/2023] [Indexed: 01/10/2023]
Affiliation(s)
- Carsten A Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland
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22
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Mohebbi N, Ritter A, Wiegand A, Graf N, Dahdal S, Sidler D, Arampatzis S, Hadaya K, Mueller TF, Wagner CA, Wüthrich RP. Sodium bicarbonate for kidney transplant recipients with metabolic acidosis in Switzerland: a multicentre, randomised, single-blind, placebo-controlled, phase 3 trial. Lancet 2023; 401:557-567. [PMID: 36708734 DOI: 10.1016/s0140-6736(22)02606-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 11/17/2022] [Accepted: 12/13/2022] [Indexed: 01/27/2023]
Abstract
BACKGROUND Metabolic acidosis is common in kidney transplant recipients and is associated with declining graft function. Sodium bicarbonate treatment effectively corrects metabolic acidosis, but no prospective studies have examined its effect on graft function. Therefore, we aimed to test whether sodium bicarbonate treatment would preserve graft function and slow the progression of estimated glomerular filtration rate (GFR) decline in kidney transplant recipients. METHODS The Preserve-Transplant Study was a multicentre, randomised, single-blind, placebo-controlled, phase 3 trial at three University Hospitals in Switzerland (Zurich, Bern, and Geneva), which recruited adult (aged ≥18 years) male and female long-term kidney transplant recipients if they had undergone transplantation more than 1 year ago. Key inclusion criteria were an estimated GFR between 15 mL/min per 1·73 m2 and 89 mL/min per 1·73 m2, stable allograft function in the last 6 months before study inclusion (<15% change in serum creatinine), and a serum bicarbonate of 22 mmol/L or less. We randomly assigned patients (1:1) to either oral sodium bicarbonate 1·5-4·5 g per day or matching placebo using web-based data management software. Randomisation was stratified by study centre and gender using a permuted block design to guarantee balanced allocation. We did multi-block randomisation with variable block sizes of two and four. Treatment duration was 2 years. Acid-resistant soft gelatine capsules of 500 mg sodium bicarbonate or matching 500 mg placebo capsules were given at an initial dose of 500 mg (if bodyweight was <70 kg) or 1000 mg (if bodyweight was ≥70 kg) three times daily. The primary endpoint was the estimated GFR slope over the 24-month treatment phase. The primary efficacy analyses were applied to a modified intention-to-treat population that comprised all randomly assigned participants who had a baseline visit. The safety population comprised all participants who received at least one dose of study drug. The trial is registered with ClinicalTrials.gov, NCT03102996. FINDINGS Between June 12, 2017, and July 10, 2019, 1114 kidney transplant recipients with metabolic acidosis were assessed for trial eligibility. 872 patients were excluded and 242 were randomly assigned to the study groups (122 [50%] to the placebo group and 120 [50%] to the sodium bicarbonate group). After secondary exclusion of two patients, 240 patients were included in the intention-to-treat analysis. The calculated yearly estimated GFR slopes over the 2-year treatment period were a median -0·722 mL/min per 1·73 m2 (IQR -4·081 to 1·440) and mean -1·862 mL/min per 1·73 m2 (SD 6·344) per year in the placebo group versus median -1·413 mL/min per 1·73 m2 (IQR -4·503 to 1·139) and mean -1·830 mL/min per 1·73 m2 (SD 6·233) per year in the sodium bicarbonate group (Wilcoxon rank sum test p=0·51; Welch t-test p=0·97). The mean difference was 0·032 mL/min per 1·73 m2 per year (95% CI -1·644 to 1·707). There were no significant differences in estimated GFR slopes in a subgroup analysis and a sensitivity analysis confirmed the primary analysis. Although the estimated GFR slope did not show a significant difference between the treatment groups, treatment with sodium bicarbonate effectively corrected metabolic acidosis by increasing serum bicarbonate from 21·3 mmol/L (SD 2·6) to 23·0 mmol/L (2·7) and blood pH from 7·37 (SD 0·06) to 7·39 (0·04) over the 2-year treatment period. Adverse events and serious adverse events were similar in both groups. Three study participants died. In the placebo group, one (1%) patient died from acute respiratory distress syndrome due to SARS-CoV-2 and one (1%) from cardiac arrest after severe dehydration following diarrhoea with hypotension, acute kidney injury, and metabolic acidosis. In the sodium bicarbonate group, one (1%) patient had sudden cardiac death. INTERPRETATION In adult kidney transplant recipients, correction of metabolic acidosis by treatment with sodium bicarbonate over 2 years did not affect the decline in estimated GFR. Thus, treatment with sodium bicarbonate should not be generally recommended to preserve estimated GFR (a surrogate marker for graft function) in kidney transplant recipients with chronic kidney disease who have metabolic acidosis. FUNDING Swiss National Science Foundation.
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Affiliation(s)
- Nilufar Mohebbi
- Division of Nephrology, University Hospital, Zurich, Switzerland.
| | - Alexander Ritter
- Division of Nephrology, University Hospital, Zurich, Switzerland
| | - Anna Wiegand
- Division of Nephrology, University Hospital, Zurich, Switzerland
| | | | - Suzan Dahdal
- Division of Nephrology and Hypertension, Inselspital, Bern, Switzerland
| | - Daniel Sidler
- Division of Nephrology and Hypertension, Inselspital, Bern, Switzerland
| | | | - Karine Hadaya
- Division of Nephrology and Hypertension, University Hospital, Geneva, Switzerland
| | - Thomas F Mueller
- Division of Nephrology, University Hospital, Zurich, Switzerland
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland
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23
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Bonny O, Fuster D, Seeger H, Ernandez T, Buchkremer F, Wuerzner G, Dhayat N, Ritter A, Stoermann C, Segerer S, Häusermann T, Pasch A, Kim M, Mayr M, Krapf R, Roth B, Bochud M, Mohebbi N, Wagner CA. The Swiss Kidney Stone Cohort: A Longitudinal, Multicentric, Observational Cohort to Study Course and Causes of Kidney Stone Disease in Switzerland. Kidney Blood Press Res 2023; 48:194-201. [PMID: 36780886 DOI: 10.1159/000529094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Accepted: 12/22/2022] [Indexed: 02/15/2023] Open
Abstract
BACKGROUND Kidney stone disease has a high prevalence worldwide of approximately 10% of the population and is characterized by a high recurrence rate. Kidney stone disease results from a combination of genetic, environmental, and lifestyle risk factors, and the dissection of these factors is complex. METHODS The Swiss Kidney Stone Cohort (SKSC) is an investigator-initiated prospective, multicentric longitudinal, observational study in patients with kidney stones followed with regular visits over a period of 3 years after inclusion. Ongoing follow-ups by biannual telephone interviews will provide long-term outcome data. SKSC comprises 782 adult patients (age >18 years) with either recurrent stones or a single stone event with at least one risk factor for recurrence. In addition, a control cohort of 207 individuals without kidney stone history and absence of kidney stones on a low-dose CT scan at enrolment has also been recruited. SKSC includes extensive collections of clinical data, biochemical data in blood and 24-h urine samples, and genetic data. Biosamples are stored at a dedicated biobank. Information on diet and dietary habits was collected through food frequency questionnaires and standardized recall interviews by trained dieticians with the Globodiet software. CONCLUSION SKSC provides a unique opportunity and resource to further study cause and course of kidney disease in a large population with data and samples collected of a homogeneous collective of patients throughout the whole Swiss population.
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Affiliation(s)
- Olivier Bonny
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
- Service of Nephrology and Hypertension, Lausanne University Hospital, Lausanne, Switzerland
- Service of Nephrology, Fribourg State Hospital, Fribourg, Switzerland
- National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland
| | - Daniel Fuster
- National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland
- Department of Nephrology and Hypertension, University Hospital Bern and University of Bern, Bern, Switzerland
| | - Harald Seeger
- Department of Nephrology, University Hospital Zurich, Zurich, Switzerland
| | - Thomas Ernandez
- Service of Nephrology, Geneva University Hospitals, Geneva, Switzerland
| | | | - Gregoire Wuerzner
- Service of Nephrology and Hypertension, Lausanne University Hospital, Lausanne, Switzerland
| | - Nasser Dhayat
- Department of Nephrology and Hypertension, University Hospital Bern and University of Bern, Bern, Switzerland
- Nephrology & Renal Care Center, B. Braun Medical Care AG, Hochfelden, Switzerland
| | - Alexander Ritter
- Department of Nephrology, University Hospital Zurich, Zurich, Switzerland
| | | | - Stephan Segerer
- Division of Nephrology, Cantonal Hospital Aarau, Aarau, Switzerland
| | - Tanja Häusermann
- National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland
| | - Andreas Pasch
- National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland
- Calciscon AG, Biel, Switzerland
| | - Minjeong Kim
- Division of Nephrology, Cantonal Hospital Aarau, Aarau, Switzerland
- Medical Outpatient Clinic, Basel University Hospital, Basel, Switzerland
| | - Michael Mayr
- Medical Outpatient Clinic, Basel University Hospital, Basel, Switzerland
| | - Reto Krapf
- National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland
| | - Beat Roth
- Department of Urology, Lausanne University Hospital, Lausanne, Switzerland
| | - Murielle Bochud
- Centre for Primary Care and Public Health (Unisanté), University of Lausanne, Lausanne, Switzerland
| | - Nilufar Mohebbi
- National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland
- Department of Nephrology and Hypertension, University Hospital Bern and University of Bern, Bern, Switzerland
| | - Carsten A Wagner
- National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland
- Institute of Physiology, University of Zurich, Zurich, Switzerland
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24
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Liu G, Riemer E, Schneider R, Cabuzu D, Bonny O, Wagner CA, Qiu D, Saiardi A, Strauss A, Lahaye T, Schaaf G, Knoll T, Jessen JP, Jessen HJ. The phytase RipBL1 enables the assignment of a specific inositol phosphate isomer as a structural component of human kidney stones. RSC Chem Biol 2023; 4:300-309. [PMID: 37034402 PMCID: PMC10074554 DOI: 10.1039/d2cb00235c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 01/26/2023] [Indexed: 01/30/2023] Open
Abstract
Inositol phosphates (InsPs) are ubiquitous in all eukaryotes. However, since there are 63 possible different phosphate ester isomers, the analysis of InsPs is challenging. In particular, InsP1, InsP2 and InsP3...
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Affiliation(s)
- Guizhen Liu
- Institute of Organic Chemistry & CIBSS-Centre for Integrative Biological Signalling Studies, University of Freiburg Germany
| | - Esther Riemer
- Institute of Crop Science and Resource Conservation, Department of Plant Nutrition, University of Bonn Germany
| | - Robin Schneider
- Institute of Crop Science and Resource Conservation, Department of Plant Nutrition, University of Bonn Germany
| | - Daniela Cabuzu
- Department of Biomedical Sciences, University of Lausanne, Switzerland and Service of Nephrology, Lausanne University Hospital Lausanne Switzerland
| | - Olivier Bonny
- Department of Biomedical Sciences, University of Lausanne, Switzerland and Service of Nephrology, Lausanne University Hospital Lausanne Switzerland
| | | | - Danye Qiu
- Institute of Organic Chemistry & CIBSS-Centre for Integrative Biological Signalling Studies, University of Freiburg Germany
| | - Adolfo Saiardi
- Laboratory for Molecular Cell Biology, University College London UK
| | | | | | - Gabriel Schaaf
- Institute of Crop Science and Resource Conservation, Department of Plant Nutrition, University of Bonn Germany
| | - Thomas Knoll
- Department of Urology, Sindelfingen-Boeblingen Medical Center, Teaching Hospital University Tübingen Sindelfingen Germany
| | - Jan P Jessen
- Department of Urology, Sindelfingen-Boeblingen Medical Center, Teaching Hospital University Tübingen Sindelfingen Germany
| | - Henning J Jessen
- Institute of Organic Chemistry & CIBSS-Centre for Integrative Biological Signalling Studies, University of Freiburg Germany
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25
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Abstract
Local acidification is a common feature of many disease processes such as inflammation, infarction, or solid tumor growth. Acidic pH is not merely a sequelae of disease but contributes to recruitment and regulation of immune cells, modifies metabolism of parenchymal, immune and tumor cells, modulates fibrosis, vascular permeability, oxygen availability and consumption, invasiveness of tumor cells, and impacts on cell survival. Thus, multiple pH-sensing mechanisms must exist in cells involved in these processes. These pH-sensors play important roles in normal physiology and pathophysiology, and hence might be attractive targets for pharmacological interventions. Among the pH-sensing mechanisms, OGR1 (GPR68), GPR4 (GPR4), and TDAG8 (GPR65) have emerged as important molecules. These G protein-coupled receptors are widely expressed, are upregulated in inflammation and tumors, sense changes in extracellular pH in the range between pH 8 and 6, and are involved in modulating key processes in inflammation, tumor biology, and fibrosis. This review discusses key features of these receptors and highlights important disease states and pathways affected by their activity.
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Affiliation(s)
- Pedro H Imenez Silva
- Institute of Physiology, University of Zurich, Zurich, Switzerland.,National Center of Competence in Research NCCR Kidney.CH, Switzerland
| | - Niels Olsen Câmara
- Department of Immunology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland.,National Center of Competence in Research NCCR Kidney.CH, Switzerland
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26
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Daryadel A, Haykir B, Küng CJ, Bugarski M, Bettoni C, Schnitzbauer U, Hernando N, Hall AM, Wagner CA. Acute adaptation of renal phosphate transporters in the murine kidney to oral phosphate intake requires multiple signals. Acta Physiol (Oxf) 2022; 235:e13815. [PMID: 35334154 DOI: 10.1111/apha.13815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 03/22/2022] [Accepted: 03/23/2022] [Indexed: 12/01/2022]
Abstract
AIMS Dietary inorganic phosphate (Pi) modulates renal Pi reabsorption by regulating the expression of the NaPi-IIa and NaPi-IIc Pi transporters. Here, we aimed to clarify the role of several Pi-regulatory mechanisms including parathyroid hormone (PTH), fibroblast growth factor 23 (FGF23) and inositol hexakisphosphate kinases (IP6-kinases) in the acute regulation of NaPi-IIa and NaPi-IIc. METHODS Wildtype (WT) and PTH-deficient mice (PTH-KO) with/without inhibition of FGF23 signalling were gavaged with Pi/saline and examined at 1, 4 and 12 h. RESULTS Pi-gavage elevated plasma Pi and decreased plasma Ca2+ in both genotypes after 1 h Within 1 h, Pi-gavage decreased NaPi-IIa abundance in WT and PTH-KO mice. NaPi-IIc was downregulated 1 h post-administration in WT and after 4 h in PTH-KO. PTH increased after 1 h in WT animals. After 4 h Pi-gavage, FGF23 increased in both genotypes being higher in the KO group. PTHrp and dopamine were not altered by Pi-gavage. Blocking FGF23 signalling blunted PTH upregulation in WT mice and reduced NaPi-IIa downregulation in PTH-KO mice 4 h after Pi-gavage. Inhibition of IP6-kinases had no effect. CONCLUSIONS (1) Acute downregulation of renal Pi transporters in response to Pi intake occurs also in the absence of PTH and FGF23 signalling, (2) when FGF23 signalling is blocked, a partial contribution of PTH is revealed, (3) IP6 kinases, intracellular Pi-sensors in yeast and bacteria, are not involved, and (4) Acute Pi does not alter PTHrp and dopamine. Thus, signals other than PTH, PTHrp, FGF23 and dopamine contribute to renal adaption.
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Affiliation(s)
- Arezoo Daryadel
- Institute of Physiology University of Zürich Zürich Switzerland
- National Center of Competence in Research Kidney.CH Zürich Switzerland
| | - Betül Haykir
- Institute of Physiology University of Zürich Zürich Switzerland
| | | | - Milica Bugarski
- National Center of Competence in Research Kidney.CH Zürich Switzerland
- Institute of Anatomy University of Zürich Zürich Switzerland
| | - Carla Bettoni
- Institute of Physiology University of Zürich Zürich Switzerland
| | | | - Nati Hernando
- Institute of Physiology University of Zürich Zürich Switzerland
| | - Andrew M. Hall
- National Center of Competence in Research Kidney.CH Zürich Switzerland
- Institute of Anatomy University of Zürich Zürich Switzerland
| | - Carsten A. Wagner
- Institute of Physiology University of Zürich Zürich Switzerland
- National Center of Competence in Research Kidney.CH Zürich Switzerland
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27
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Jönsson ÅLM, Hernando N, Knöpfel T, Mogensen S, Bendstrup E, Hilberg O, Christensen JH, Simonsen U, Wagner CA. Impaired phosphate transport in SLC34A2 variants in patients with pulmonary alveolar microlithiasis. Hum Genomics 2022; 16:13. [PMID: 35443721 PMCID: PMC9019944 DOI: 10.1186/s40246-022-00387-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Accepted: 03/23/2022] [Indexed: 11/26/2022] Open
Abstract
Background Variants in SLC34A2 encoding the sodium-dependent phosphate transport protein 2b (NaPi-IIb) cause the rare lung disease pulmonary alveolar microlithiasis (PAM). PAM is characterised by the deposition of calcium-phosphate concretions in the alveoli usually progressing over time. No effective treatment is available. So far, 30 allelic variants in patients have been reported but only a few have been functionally characterised. This study aimed to determine the impact of selected SLC34A2 variants on transporter expression and phosphate uptake in cellular studies. Methods Two nonsense variants (c.910A > T and c.1456C > T), one frameshift (c.1328delT), and one in-frame deletion (c.1402_1404delACC) previously reported in patients with PAM were selected for investigation. Wild-type and mutant c-Myc-tagged human NaPi-IIb constructs were expressed in Xenopus laevis oocytes. The transport function was investigated with a 32Pi uptake assay. NaPi-IIb protein expression and localisation were determined with immunoblotting and immunohistochemistry, respectively. Results Oocytes injected with the wild-type human NaPi-IIb construct had significant 32Pi transport compared to water-injected oocytes. In addition, the protein had a molecular weight as expected for the glycosylated form, and it was readily detectable in the oocyte membrane. Although the protein from the Thr468del construct was synthesised and expressed in the oocyte membrane, phosphate transport was similar to non-injected control oocytes. All other mutants were non-functional and not expressed in the membrane, consistent with the expected impact of the truncations caused by premature stop codons. Conclusions Of four analysed SLC34A2 variants, only the Thr468del showed similar protein expression as the wild-type cotransporter in the oocyte membrane. All mutant transporters were non-functional, supporting that dysfunction of NaPi-IIb underlies the pathology of PAM. Supplementary Information The online version contains supplementary material available at 10.1186/s40246-022-00387-y.
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Affiliation(s)
- Åsa Lina M Jönsson
- Department of Biomedicine, Aarhus University, Aarhus, Denmark. .,Department of Clinical Genetics, Aarhus University Hospital, Aarhus, Denmark.
| | - Nati Hernando
- Institute of Physiology, University of Zurich, Zurich, Switzerland.,Swiss National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland
| | - Thomas Knöpfel
- Institute of Physiology, University of Zurich, Zurich, Switzerland.,Swiss National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland
| | - Susie Mogensen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Elisabeth Bendstrup
- Centre for Rare Lung Diseases, Department of Respiratory Diseases and Allergy, Aarhus University Hospital, Aarhus, Denmark
| | - Ole Hilberg
- Medical Department, Vejle Hospital, Vejle, Denmark
| | | | - Ulf Simonsen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland.,Swiss National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland
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28
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Abstract
The detection of H+ concentration variations in the extracellular milieu is accomplished by a series of specialized and non-specialized pH-sensing mechanisms. The proton-activated G protein–coupled receptors (GPCRs) GPR4 (Gpr4), TDAG8 (Gpr65), and OGR1 (Gpr68) form a subfamily of proteins capable of triggering intracellular signaling in response to alterations in extracellular pH around physiological values, i.e., in the range between pH 7.5 and 6.5. Expression of these receptors is widespread for GPR4 and OGR1 with particularly high levels in endothelial cells and vascular smooth muscle cells, respectively, while expression of TDAG8 appears to be more restricted to the immune compartment. These receptors have been linked to several well-studied pH-dependent physiological activities including central control of respiration, renal adaption to changes in acid–base status, secretion of insulin and peripheral responsiveness to insulin, mechanosensation, and cellular chemotaxis. Their role in pathological processes such as the genesis and progression of several inflammatory diseases (asthma, inflammatory bowel disease), and tumor cell metabolism and invasiveness, is increasingly receiving more attention and makes these receptors novel and interesting targets for therapy. In this review, we cover the role of these receptors in physiological processes and will briefly discuss some implications for disease processes.
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Affiliation(s)
- Pedro H Imenez Silva
- Institute of Physiology, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland. .,National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland.
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland. .,National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland.
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29
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Ugrica M, Gehring N, Giesbertz P, Pastor-Arroyo EM, Daniel H, Wagner CA, Rubio-Aliaga I. Chronic High Phosphate Intake in Mice Affects Macronutrient Utilization and Body Composition. Mol Nutr Food Res 2022; 66:e2100949. [PMID: 35194921 DOI: 10.1002/mnfr.202100949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 02/04/2022] [Indexed: 11/11/2022]
Abstract
SCOPE In the last decades, dietary phosphate intake has increased due to a higher consumption of processed food. This higher intake has an impact on body composition and health state. Recently, we found that a high chronic phosphate diet leads to no major renal alterations, but negatively affects parameters of bone health probably due to the chronic acid load. Here we assessed the effect of high phosphate consumption on parameters of energy metabolism. METHODS AND RESULTS Healthy mature adult mice were fed for 1 year or four months with either a standard (0.6 % w/w) or a high phosphate (1.2 % w/w) diet. Males and females of two different genetic backgrounds were investigated. Mice fed the high phosphate diet showed an attenuated body-weight gain, lower respiratory exchange ratio, decreased body fat mass and increased lean-to-fat mass ratio. Moreover, the high phosphate diet led to fasting hypoglycemia with no differences in the glucose response to an oral glucose tolerance test. Triglycerides and cholesterol in blood were similar independently of dietary phosphate content. However, 1-methylhistidine was lower in animals fed a chronic high phosphate intake. CONCLUSIONS High phosphate diet attenuates body weight gain, but induces hypoglycaemia and may alter muscle homeostasis. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Marko Ugrica
- Institute of Physiology, University of Zurich, and National Center of Competence in Research NCCR Kidney, Zurich, 8057, Switzerland
| | - Nicole Gehring
- Institute of Physiology, University of Zurich, and National Center of Competence in Research NCCR Kidney, Zurich, 8057, Switzerland
| | - Pieter Giesbertz
- Nutritional Physiology, Technical University of Munich, Freising, 85354, Germany
| | - Eva-Maria Pastor-Arroyo
- Institute of Physiology, University of Zurich, and National Center of Competence in Research NCCR Kidney, Zurich, 8057, Switzerland
| | - Hannelore Daniel
- Nutritional Physiology, Technical University of Munich, Freising, 85354, Germany
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich, and National Center of Competence in Research NCCR Kidney, Zurich, 8057, Switzerland
| | - Isabel Rubio-Aliaga
- Institute of Physiology, University of Zurich, and National Center of Competence in Research NCCR Kidney, Zurich, 8057, Switzerland
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30
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Weder B, Schefer F, van Haaften WT, Patsenker E, Stickel F, Mueller S, Hutter S, Schuler C, Baebler K, Wang Y, Mamie C, Dijkstra G, de Vallière C, Imenez Silva PH, Wagner CA, Frey-Wagner I, Ruiz PA, Seuwen K, Rogler G, Hausmann M. New Therapeutic Approach for Intestinal Fibrosis Through Inhibition of pH-Sensing Receptor GPR4. Inflamm Bowel Dis 2022; 28:109-125. [PMID: 34320209 DOI: 10.1093/ibd/izab140] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Indexed: 02/06/2023]
Abstract
BACKGROUND Patients suffering from inflammatory bowel diseases (IBDs) express increased mucosal levels of pH-sensing receptors compared with non-IBD controls. Acidification leads to angiogenesis and extracellular matrix remodeling. We aimed to determine the expression of pH-sensing G protein-coupled receptor 4 (GPR4) in fibrotic lesions in Crohn's disease (CD) patients. We further evaluated the effect of deficiency in Gpr4 or its pharmacologic inhibition. METHODS Paired samples from fibrotic and nonfibrotic terminal ileum were obtained from CD patients undergoing ileocaecal resection. The effects of Gpr4 deficiency were assessed in the spontaneous Il-10-/- and the chronic dextran sodium sulfate (DSS) murine colitis model. The effects of Gpr4 deficiency and a GPR4 antagonist (39c) were assessed in the heterotopic intestinal transplantation model. RESULTS In human terminal ileum, increased expression of fibrosis markers was accompanied by an increase in GPR4 expression. A positive correlation between the expression of procollagens and GPR4 was observed. In murine disease models, Gpr4 deficiency was associated with a decrease in angiogenesis and fibrogenesis evidenced by decreased vessel length and expression of Edn, Vegfα, and procollagens. The heterotopic animal model for intestinal fibrosis, transplanted with terminal ileum from Gpr4-/- mice, revealed a decrease in mRNA expression of fibrosis markers and a decrease in collagen content and layer thickness compared with grafts from wild type mice. The GPR4 antagonist decreased collagen deposition. The GPR4 expression was also observed in human and murine intestinal fibroblasts. The GPR4 inhibition reduced markers of fibroblast activation stimulated by low pH, notably Acta2 and cTgf. CONCLUSIONS Expression of GPR4 positively correlates with the expression of profibrotic genes and collagen. Deficiency of Gpr4 is associated with a decrease in angiogenesis and fibrogenesis. The GPR4 antagonist decreases collagen deposition. Targeting GPR4 with specific inhibitors may constitute a new treatment option for IBD-associated fibrosis.
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Affiliation(s)
- Bruce Weder
- Department of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland
| | - Fabian Schefer
- Department of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland
| | - Wouter Tobias van Haaften
- Department of Gastroenterology and Hepatology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands.,Department of Pharmaceutical Technology and Biopharmacy, Groningen Research Institute of Pharmacy, University of Groningen, Groningen, the Netherlands
| | - Eleonora Patsenker
- Department of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland
| | - Felix Stickel
- Department of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland
| | - Sebastian Mueller
- Department of Internal Medicine and Center for Alcohol Research, Salem Medical Center University Hospital Heidelberg, Heidelberg, Germany
| | - Senta Hutter
- Department of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland
| | - Cordelia Schuler
- Department of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland
| | - Katharina Baebler
- Department of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland
| | - Yu Wang
- Department of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland
| | - Céline Mamie
- Department of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland
| | - Gerard Dijkstra
- Department of Gastroenterology and Hepatology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - Cheryl de Vallière
- Department of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland
| | - Pedro H Imenez Silva
- Institute of Physiology, University of Zurich, Zurich, Switzerland and National Center of Competence in Research Kidney Control of Homeostasis, Switzerland
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland and National Center of Competence in Research Kidney Control of Homeostasis, Switzerland
| | - Isabelle Frey-Wagner
- Department of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland
| | - Pedro A Ruiz
- Department of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland
| | - Klaus Seuwen
- Novartis Institutes for Biomedical Research, Forum1 Novartis Campus, Basel, Switzerland
| | - Gerhard Rogler
- Department of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland
| | - Martin Hausmann
- Department of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland
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Aljuraibah F, Bacchetta J, Brandi ML, Florenzano P, Javaid MK, Mäkitie O, Raimann A, Rodriguez M, Siggelkow H, Tiosano D, Vervloet M, Wagner CA. An Expert Perspective on Phosphate Dysregulation With a Focus on Chronic Hypophosphatemia. J Bone Miner Res 2022; 37:12-20. [PMID: 34870347 PMCID: PMC9306528 DOI: 10.1002/jbmr.4486] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 11/18/2021] [Accepted: 11/27/2021] [Indexed: 12/11/2022]
Abstract
Because of their rarity, diseases characterized by chronic hypophosphatemia can be underrecognized and suboptimally managed, resulting in poor clinical outcomes. Moreover, serum phosphate may not be measured routinely in primary care practice. Authors participated in several working sessions to advance the understanding of phosphate homeostasis and the causes, consequences, and clinical implications of chronic hypophosphatemia. Phosphate levels are regulated from birth to adulthood. Dysregulation of phosphate homeostasis can result in hypophosphatemia, which becomes chronic if phosphate levels cannot be normalized. Chronic hypophosphatemia may be underrecognized as serum phosphate measurement is not always part of routine analysis in the primary care setting and results might be misinterpreted, for instance, due to age-specific differences not being accounted for and circadian variations. Clinical consequences of chronic hypophosphatemia involve disordered endocrine regulation, affect multiple organ systems, and vary depending on patient age and the underlying disorder. Signs and symptoms of chronic hypophosphatemic diseases that manifest during childhood or adolescence persist into adulthood if the disease is inadequately managed, resulting in an accumulation of clinical deficits and a progressive, debilitating impact on quality of life. Early identification and diagnosis of patients with chronic hypophosphatemia is crucial, and clinical management should be started as soon as possible to maximize the likelihood of improving health outcomes. Furthermore, in the absence of a universally accepted description for "chronic hypophosphatemia," a definition is proposed here that aims to raise awareness of these diseases, facilitate diagnosis, and guide optimal phosphate management strategies by improving monitoring and assessment of patient response to treatment. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Fahad Aljuraibah
- College of Medicine, King Saud bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
| | | | | | | | | | - Outimaija Mäkitie
- Children's Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | | | | | | | | | - Marc Vervloet
- Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Carsten A Wagner
- University of Zurich, Zurich.,Swiss National Center of Competence in Research NCCR Kidney.CH, Zurich
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Küng CJ, Haykir B, Schnitzbauer U, Egli-Spichtig D, Hernando N, Wagner CA. Fibroblast growth factor 23 leads to endolysosomal routing of the renal phosphate cotransporters NaPi-IIa and NaPi-IIc in vivo. Am J Physiol Renal Physiol 2021; 321:F785-F798. [PMID: 34719948 DOI: 10.1152/ajprenal.00250.2021] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Na+-dependent phosphate cotransporters NaPi-IIa and NaPi-IIc, located at the brush-border membrane of renal proximal tubules, are regulated by numerous factors, including fibroblast growth factor 23 (FGF23). FGF23 downregulates NaPi-IIa and NaPi-IIc abundance after activating a signaling pathway involving phosphorylation of ERK1/2 (phospho-ERK1/2). FGF23 also downregulates expression of renal 1-α-hydroxylase (Cyp27b1) and upregulates 24-hydroxylase (Cyp24a1), thus reducing plasma calcitriol levels. Here, we examined the time course of FGF23-induced internalization of NaPi-IIa and NaPi-IIc and their intracellular pathway toward degradation in vivo. Mice were injected intraperitoneally with recombinant human (rh)FGF23 in the absence (biochemical analysis) or presence (immunohistochemistry) of leupeptin, an inhibitor of lysosomal proteases. Phosphorylation of ERK1/2 was enhanced 60 min after rhFGF23 administration, and increased phosphorylation was still detected 480 min after injection. Colocalization of phospho-ERK1/2 with NaPi-IIa was seen at 60 and 120 min and partly at 480 min. The abundance of both cotransporters was reduced 240 min after rhFGF23 administration, with a further reduction at 480 min. NaPi-IIa and NaPi-IIc were found to colocalize with clathrin and early endosomal antigen 1 as early as 120 min after rhFGF23 injection. Both cotransporters partially colocalized with cathepsin B and lysosomal-associated membrane protein-1, markers of lysosomes, 120 min after rhFGF23 injection. Thus, NaPi-IIa and NaPi-IIc are internalized within 2 h upon rhFGF23 injection. Both cotransporters share the pathway of clathrin-mediated endocytosis that leads first to early endosomes, finally resulting in trafficking toward the lysosome as early as 120 min after rhFGF23 administration.NEW & NOTEWORTHY The hormone fibroblast growth factor 23 (FGF23) controls phosphate homeostasis by regulating renal phosphate excretion. FGF23 acts on several phosphate transporters in the kidney. Here, we define the time course of this action and demonstrate how phosphate transporters NaPi-IIa and NaPi-IIc are internalized.
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Affiliation(s)
- Catharina J Küng
- Institute of Physiology, University of Zurich and National Center of Competence in Research Kidney.CH, Zurich, Switzerland
| | - Betül Haykir
- Institute of Physiology, University of Zurich and National Center of Competence in Research Kidney.CH, Zurich, Switzerland
| | - Udo Schnitzbauer
- Institute of Physiology, University of Zurich and National Center of Competence in Research Kidney.CH, Zurich, Switzerland
| | - Daniela Egli-Spichtig
- Institute of Physiology, University of Zurich and National Center of Competence in Research Kidney.CH, Zurich, Switzerland
| | - Nati Hernando
- Institute of Physiology, University of Zurich and National Center of Competence in Research Kidney.CH, Zurich, Switzerland
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich and National Center of Competence in Research Kidney.CH, Zurich, Switzerland
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33
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Ruiz-Serrano A, Monné Rodríguez JM, Günter J, Sherman SPM, Jucht AE, Fluechter P, Volkova YL, Pfundstein S, Pellegrini G, Wagner CA, Schneider C, Wenger RH, Scholz CC. OTUB1 regulates lung development, adult lung tissue homeostasis, and respiratory control. FASEB J 2021; 35:e22039. [PMID: 34793600 DOI: 10.1096/fj.202100346r] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 09/17/2021] [Accepted: 10/28/2021] [Indexed: 12/30/2022]
Abstract
OTUB1 is one of the most highly expressed deubiquitinases, counter-regulating the two most abundant ubiquitin chain types. OTUB1 expression is linked to the development and progression of lung cancer and idiopathic pulmonary fibrosis in humans. However, the physiological function of OTUB1 is unknown. Here, we show that constitutive whole-body Otub1 deletion in mice leads to perinatal lethality by asphyxiation. Analysis of (single-cell) RNA sequencing and proteome data demonstrated that OTUB1 is expressed in all lung cell types with a particularly high expression during late-stage lung development (E16.5, E18.5). At E18.5, the lungs of animals with Otub1 deletion presented with increased cell proliferation that decreased saccular air space and prevented inhalation. Flow cytometry-based analysis of E18.5 lung tissue revealed that Otub1 deletion increased proliferation of major lung parenchymal and mesenchymal/other non-hematopoietic cell types. Adult mice with conditional whole-body Otub1 deletion (wbOtub1del/del ) also displayed increased lung cell proliferation in addition to hyperventilation and failure to adapt the respiratory pattern to hypoxia. On the molecular level, Otub1 deletion enhanced mTOR signaling in embryonic and adult lung tissues. Based on these results, we propose that OTUB1 is a negative regulator of mTOR signaling with essential functions for lung cell proliferation, lung development, adult lung tissue homeostasis, and respiratory regulation.
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Affiliation(s)
| | - Josep M Monné Rodríguez
- Laboratory for Animal Model Pathology (LAMP), Institute of Veterinary Pathology, University of Zurich, Zurich, Switzerland
| | - Julia Günter
- Institute of Physiology, University of Zurich, Zurich, Switzerland.,National Centre of Competence in Research 'Kidney.CH', Zurich, Switzerland
| | | | | | - Pascal Fluechter
- Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Yulia L Volkova
- Institute of Physiology, University of Zurich, Zurich, Switzerland
| | | | - Giovanni Pellegrini
- Laboratory for Animal Model Pathology (LAMP), Institute of Veterinary Pathology, University of Zurich, Zurich, Switzerland
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland.,National Centre of Competence in Research 'Kidney.CH', Zurich, Switzerland
| | | | - Roland H Wenger
- Institute of Physiology, University of Zurich, Zurich, Switzerland.,National Centre of Competence in Research 'Kidney.CH', Zurich, Switzerland
| | - Carsten C Scholz
- Institute of Physiology, University of Zurich, Zurich, Switzerland.,National Centre of Competence in Research 'Kidney.CH', Zurich, Switzerland
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Viggiano D, Bruchfeld A, Carriazo S, de Donato A, Endlich N, Ferreira AC, Figurek A, Fouque D, Franssen CFM, Giannakou K, Goumenos D, Hoorn EJ, Nitsch D, Arduan AO, Pešić V, Rastenyté D, Soler MJ, Rroji M, Trepiccione F, Unwin RJ, Wagner CA, Wiecek A, Zacchia M, Zoccali C, Capasso G. Brain dysfunction in tubular and tubulointerstitial kidney diseases. Nephrol Dial Transplant 2021; 37:ii46-ii55. [PMID: 34792176 PMCID: PMC8713153 DOI: 10.1093/ndt/gfab276] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Indexed: 11/14/2022] Open
Abstract
Kidney function has two important elements: glomerular filtration and tubular function (secretion and reabsorption). A persistent decrease in glomerular filtration rate (GFR), with or without proteinuria, is diagnostic of chronic kidney disease (CKD). While glomerular injury or disease is a major cause of CKD and usually associated with proteinuria, predominant tubular injury, with or without tubulointerstitial disease, is typically non-proteinuric. CKD has been linked with cognitive impairment, but it is unclear how much this depends on a reduced GFR, altered tubular function or the presence of proteinuria. Since CKD is often accompanied by tubular and interstitial dysfunction, we explore here for the first time the potential role of the tubular and tubulointerstitial compartments in cognitive dysfunction. To help address this issue, we have selected a group of primary tubular diseases with preserved GFR, in which to review the evidence for any association with brain dysfunction. Cognition, mood, neurosensory, and motor disturbances are not well characterized in tubular diseases, possibly because they are subclinical and less prominent than other clinical manifestations. The available literature suggests that brain dysfunction in tubular and tubulointerstitial diseases is usually mild and is more often seen in disorders of water handling. Brain dysfunction may occur when severe electrolyte and water disorders in young children persist over a long period of time before the diagnosis is made. We have chosen as examples to highlight this topic, Bartter and Gitelman syndromes and nephrogenic diabetes insipidus. We discuss current published findings, some unanswered questions, and propose topics for future research.
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Affiliation(s)
- Davide Viggiano
- Department of Translational Medical Sciences, Univ. Campania "L.Vanvitelli", Naples, Italy. BIOGEM, Institute of Molecular Biology and Genetics, Ariano Irpino. Italy
| | - Annette Bruchfeld
- Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden. Department of Renal Medicine, Karolinska University Hospital and CLINTEC Karolinska Institutet, Stockholm, Sweden
| | - Sol Carriazo
- Department of Nephrology and Hypertension, IIS-Fundacion Jimenez Diaz-UAM, Madrid, Spain
| | - Antonio de Donato
- Department of Translational Medical Sciences, Univ. Campania "L.Vanvitelli", Naples, Italy. BIOGEM, Institute of Molecular Biology and Genetics, Ariano Irpino. Italy
| | - Nicole Endlich
- Department of Anatomy and Cell Biology, University Medicine Greifswald, Germany
| | - Ana Carina Ferreira
- Nephrology Department, Centro Hospitalar E Universitário de Lisboa Central, Lisbon, Portugal; Universidade Nova de Lisboa
- Faculdade de Ciências Médicas, Lisbon, Portugal
| | - Andreja Figurek
- Institute of Anatomy, University of Zurich, Zurich, Switzerland
| | - Denis Fouque
- Department of Nephrology, Hospices Civils de Lyon, Centre Hospitalier Lyon-Sud, Pierre-Benite, France; University of Lyon, France
| | - Casper F M Franssen
- Department of Nephrology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Konstantinos Giannakou
- Department of Health Sciences, School of Sciences, European University Cyprus, Nicosia, Cyprus
| | - Dimitrios Goumenos
- Department of Nephrology and Renal Transplantation, Patras University Hospital, Patras, Greece
| | - Ewout J Hoorn
- Department of Internal Medicine, Division of Nephrology and Transplantation, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Dorothea Nitsch
- Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Alberto Ortiz Arduan
- Department of Nephrology and Hypertension, IIS-Fundacion Jimenez Diaz-UAM, Madrid, Spain
| | - Vesna Pešić
- Department of Physiology, Faculty of Pharmacy, University of Belgrade, Belgrade, Serbia
| | - Daiva Rastenyté
- Medical Academy, Department of Neurology, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Maria José Soler
- Nephrology Department, Vall d'Hebron Barcelona Hospital Campus, Barcelona, Spain
| | - Merita Rroji
- Department of Nephrology, University Hospital Center "Mother Tereza", Tirana, Albania
| | - Francesco Trepiccione
- Department of Translational Medical Sciences, Univ. Campania "L.Vanvitelli", Naples, Italy. BIOGEM, Institute of Molecular Biology and Genetics, Ariano Irpino, Italy
| | - Robert J Unwin
- Department of Renal Medicine, Division of Medicine, University College London, UK
| | - Carsten A Wagner
- Institute of Physiology, University of Zürich, Zurich, Switzerland
| | - Andrzej Wiecek
- Department of Nephrology, Transplantation and Internal Medicine, Medical University of Silesia, Katowice, Poland
| | - Miriam Zacchia
- Department of Translational Medical Sciences, Univ. Campania "L.Vanvitelli", Naples, Italy. BIOGEM, Institute of Molecular Biology and Genetics, Ariano Irpino, Italy
| | - Carmine Zoccali
- Renal Research Institute, New York, USA and Associazione Ipertensione, Nefrologia, Trapianto Renale (IPNET), Italy
| | - Giovambattista Capasso
- Department of Translational Medical Sciences, Univ. Campania "L.Vanvitelli", Naples, Italy. BIOGEM, Institute of Molecular Biology and Genetics, Ariano Irpino, Italy
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Imenez Silva PH, Unwin R, Hoorn EJ, Ortiz A, Trepiccione F, Nielsen R, Pesic V, Hafez G, Fouque D, Massy ZA, De Zeeuw CI, Capasso G, Wagner CA. Acidosis, cognitive dysfunction and motor impairments in patients with kidney disease. Nephrol Dial Transplant 2021; 37:ii4-ii12. [PMID: 34718761 PMCID: PMC8713149 DOI: 10.1093/ndt/gfab216] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Indexed: 12/20/2022] Open
Abstract
Metabolic acidosis, defined as a plasma or serum bicarbonate concentration <22 mmol/L, is a frequent consequence of chronic kidney disease (CKD) and occurs in ~10–30% of patients with advanced stages of CKD. Likewise, in patients with a kidney transplant, prevalence rates of metabolic acidosis range from 20% to 50%. CKD has recently been associated with cognitive dysfunction, including mild cognitive impairment with memory and attention deficits, reduced executive functions and morphological damage detectable with imaging. Also, impaired motor functions and loss of muscle strength are often found in patients with advanced CKD, which in part may be attributed to altered central nervous system (CNS) functions. While the exact mechanisms of how CKD may cause cognitive dysfunction and reduced motor functions are still debated, recent data point towards the possibility that acidosis is one modifiable contributor to cognitive dysfunction. This review summarizes recent evidence for an association between acidosis and cognitive dysfunction in patients with CKD and discusses potential mechanisms by which acidosis may impact CNS functions. The review also identifies important open questions to be answered to improve prevention and therapy of cognitive dysfunction in the setting of metabolic acidosis in patients with CKD.
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Affiliation(s)
- Pedro H Imenez Silva
- Institute of Physiology, University of Zurich, Zürich, Switzerland.,National Center of Competence in Research NCCR Kidney.CH, Zürich, Switzerland
| | - Robert Unwin
- Department of Renal Medicine, Royal Free Hospital, University College London, London, UK
| | - Ewout J Hoorn
- Department of Internal Medicine, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Alberto Ortiz
- Department of Nephrology and Hypertension, IIS-Fundacion Jimenez Diaz, Universidad Autonoma de Madrid, Madrid, Spain
| | - Francesco Trepiccione
- Biogem Institute of Molecular Biology and Genetics, Ariano Irpino, Italy.,Department of Translational Medical Sciences, University of Campania "Luigi Vanvitelli," Naples, Italy
| | - Rikke Nielsen
- Department of Biomedicine-Anatomy, University of Aarhus, Aarhus, Denmark
| | - Vesna Pesic
- Department of Physiology, Faculty of Pharmacy, University of Belgrade, Belgrade, Serbia
| | - Gaye Hafez
- Department of Pharmacology, Faculty of Pharmacy, Altinbas University, Istanbul, Turkey
| | - Denis Fouque
- CarMeN, INSERM 1060, Université Claude Bernard Lyon 1, Lyon, France.,Service de Néphrologie, Lyon-Sud Hospital, Pierre-Bénite, France
| | - Ziad A Massy
- Department of Nephrology, Ambroise Paré University Hospital, Assistance Publique Hôpitaux de Paris, Boulogne-Billancourt, France.,Centre de Recherche en Epidémiologie et Santé des Populations, Institut National de la Santé et de la Recherche Médicale U1018-Team 5, Université de Versailles Saint-Quentin-en-Yvelines, University Paris Saclay, Villejuif, France
| | - Chris I De Zeeuw
- Department of Neuroscience, Erasmus Medical Center, University Medical Center Rotterdam, Rotterdam, The Netherlands.,Netherlands Institute for Neuroscience, Royal Dutch Academy of Art and Science, Amsterdam, The Netherlands
| | - Giovambattista Capasso
- Biogem Institute of Molecular Biology and Genetics, Ariano Irpino, Italy.,Department of Translational Medical Sciences, University of Campania "Luigi Vanvitelli," Naples, Italy
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich, Zürich, Switzerland.,National Center of Competence in Research NCCR Kidney.CH, Zürich, Switzerland
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Gehring N, Bettoni C, Wagner CA, Rubio-Aliaga I. Jak1/Stat3 Activation Alters Phosphate Metabolism Independently of Sex and Extracellular Phosphate Levels. Kidney Blood Press Res 2021; 46:714-722. [PMID: 34515136 DOI: 10.1159/000518488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 07/12/2021] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION Phosphate homeostasis is regulated by a complex network involving the parathyroid hormone (PTH), fibroblast growth factor 23 (FGF23), and calcitriol acting on several organs including the kidney, intestine, bone, and parathyroid gland. Previously, we showed that activation of the Janus kinase 1 (Jak1)-signal transducer and activator of transcription 3 (Stat3) signaling pathway leads to altered mineral metabolism with higher FGF23 levels, lower PTH, and higher calcitriol levels. Here, we investigated if there are sex differences in the role of Jak1/Stat3 signaling pathway on phosphate metabolism and if this pathway is sensitive to extracellular phosphate alterations. METHODS We used a mouse model (Jak1S645P+/-) that resembles a constitutive activating mutation of the Jak1/Stat3 signaling pathway in humans and analyzed the impact of sex on mineral metabolism parameters. Furthermore, we challenged Jak1S645P+/- male and female mice with a high (1.2% w/w) and low (0.1% w/w) phosphate diet and a diet with phosphate with organic origin with lower bioavailability. RESULTS Female mice, as male mice, showed higher intact FGF23 levels but no phosphaturia, and higher calcitriol and lower PTH levels in plasma. A phosphate challenge did not alter the effect of Jak1/Stat3 activation on phosphate metabolism for both genders. However, under a low phosphate diet or a diet with lower phosphate availability, the animals showed a tendency to develop hypophosphatemia. Moreover, male and female mice showed similar phosphate metabolism parameters. The only exception was higher PTH levels in male mice than those in females. DISCUSSION/CONCLUSION Sex and extracellular phosphate levels do not affect the impact of Jak1/Stat3 activation on phosphate metabolism.
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Affiliation(s)
- Nicole Gehring
- Institute of Physiology, University of Zurich, National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland
| | - Carla Bettoni
- Institute of Physiology, University of Zurich, National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich, National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland
| | - Isabel Rubio-Aliaga
- Institute of Physiology, University of Zurich, National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland
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37
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Figueiredo M, Daryadel A, Sihn G, Müller DN, Popova E, Rouselle A, Nguyen G, Bader M, Wagner CA. The (pro)renin receptor (ATP6ap2) facilitates receptor-mediated endocytosis and lysosomal function in the renal proximal tubule. Pflugers Arch 2021; 473:1229-1246. [PMID: 34228176 PMCID: PMC8302575 DOI: 10.1007/s00424-021-02598-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 05/26/2021] [Accepted: 06/16/2021] [Indexed: 12/16/2022]
Abstract
The ATP6ap2 (Pro)renin receptor protein associates with H+-ATPases which regulate organellar, cellular, and systemic acid-base homeostasis. In the kidney, ATP6ap2 colocalizes with H+-ATPases in various cell types including the cells of the proximal tubule. There, H+-ATPases are involved in receptor-mediated endocytosis of low molecular weight proteins via the megalin/cubilin receptors. To study ATP6ap2 function in the proximal tubule, we used an inducible shRNA Atp6ap2 knockdown rat model (Kd) and an inducible kidney-specific Atp6ap2 knockout mouse model. Both animal lines showed higher proteinuria with elevated albumin, vitamin D binding protein, and procathepsin B in urine. Endocytosis of an injected fluid-phase marker (FITC- dextran, 10 kDa) was normal whereas processing of recombinant transferrin, a marker for receptor-mediated endocytosis, to lysosomes was delayed. While megalin and cubilin expression was unchanged, abundance of several subunits of the H+-ATPase involved in receptor-mediated endocytosis was reduced. Lysosomal integrity and H+-ATPase function are associated with mTOR signaling. In ATP6ap2, KO mice mTOR and phospho-mTOR appeared normal but increased abundance of the LC3-B subunit of the autophagosome was observed suggesting a more generalized impairment of lysosomal function in the absence of ATP6ap2. Hence, our data suggests a role for ATP6ap2 for proximal tubule function in the kidney with a defect in receptor-mediated endocytosis in mice and rats.
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Affiliation(s)
- Marta Figueiredo
- Institute of Physiology, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Arezoo Daryadel
- Institute of Physiology, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Gabin Sihn
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Str. 10, 13125, Berlin, Germany
| | - Dominik N Müller
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Str. 10, 13125, Berlin, Germany
- Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine, Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), partner site Berlin, Berlin, Germany
| | - Elena Popova
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Str. 10, 13125, Berlin, Germany
| | - Anthony Rouselle
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Str. 10, 13125, Berlin, Germany
| | | | - Michael Bader
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Robert-Rössle-Str. 10, 13125, Berlin, Germany.
- DZHK (German Centre for Cardiovascular Research), partner site Berlin, Berlin, Germany.
- Charite University Medicine Berlin, Berlin, Germany.
- Institute for Biology, University of Lübeck, Lübeck, Germany.
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland.
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Fuente R, Gehring N, Bettoni C, Gil-Peña H, Alonso-Durán L, Michalke B, Santos F, Wagner CA, Rubio-Aliaga I. Systemic Jak1 activation causes extrarenal calcitriol production and skeletal alterations provoking stunted growth. FASEB J 2021; 35:e21721. [PMID: 34118090 DOI: 10.1096/fj.202100587r] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 05/12/2021] [Accepted: 05/20/2021] [Indexed: 02/06/2023]
Abstract
Mineral homeostasis is regulated by a complex network involving endocrine actions by calcitriol, parathyroid hormone (PTH), and FGF23 on several organs including kidney, intestine, and bone. Alterations of mineral homeostasis are found in chronic kidney disease and other systemic disorders. The interplay between the immune system and the skeletal system is not fully understood, but cytokines play a major role in modulating calcitriol production and function. One of the main cellular signaling pathways mediating cytokine function is the Janus kinase (JAK)--signal transducer and activator of transcription (STAT) pathway. Here, we used a mouse model (Jak1S645P+/- ) that resembles a constitutive activating mutation of the Jak1/Stat3 signaling pathway in humans, and shows altered mineral metabolism, with higher fibroblast growth factor 23 (FGF23) levels, lower PTH levels, and higher calcitriol levels. The higher calcitriol levels are probably due to extrarenal calcitriol production. Furthermore, systemic Jak1/Stat3 activation led to growth impairment and skeletal alterations. The growth plate in long bones showed decreased chondrocyte proliferation rates and reduced height of terminal chondrocytes. Furthermore, we demonstrate that Jak1 is also involved in bone remodeling early in life. Jak1S645P+/- animals have decreased bone and cortical volume, imbalanced bone remodeling, reduced MAP kinase signaling, and local inflammation. In conclusion, Jak1 plays a major role in bone health probably both, directly and systemically by regulating mineral homeostasis. Understanding the role of this signaling pathway will contribute to a better knowledge in bone growth and in mineral physiology, and to the development of selective Jak inhibitors as osteoprotective agents.
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Affiliation(s)
- Rocío Fuente
- Institute of Physiology, University of Zurich, Zurich, Switzerland.,National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland.,Division of Pediatrics, University of Oviedo, Oviedo, Spain
| | - Nicole Gehring
- Institute of Physiology, University of Zurich, Zurich, Switzerland.,National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland
| | - Carla Bettoni
- Institute of Physiology, University of Zurich, Zurich, Switzerland.,National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland
| | | | | | - Bernhard Michalke
- Department of Environmental Science, Research Unit Analytical, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany
| | - Fernando Santos
- Division of Pediatrics, University of Oviedo, Oviedo, Spain.,Department of Pediatrics, Hospital Universitario Central de Asturias, Oviedo, Spain
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland.,National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland
| | - Isabel Rubio-Aliaga
- Institute of Physiology, University of Zurich, Zurich, Switzerland.,National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland
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Silva PHI, Wiegand A, Daryadel A, Russo G, Ritter A, Gaspert A, Wüthrich RP, Wagner CA, Mohebbi N. Acidosis and alkali therapy in patients with kidney transplant is associated with transcriptional changes and altered abundance of genes involved in cell metabolism and acid-base balance. Nephrol Dial Transplant 2021; 36:1806-1820. [PMID: 34240183 DOI: 10.1093/ndt/gfab210] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Metabolic acidosis occurs frequently in patients with kidney transplant and is associated with higher risk for and accelerated loss of graft function. To date, it is not known whether alkali therapy in these patients improves kidney function and whether acidosis and its therapy is associated with altered expression of proteins involved in renal acid-base metabolism. METHODS We collected retrospectively kidney biopsies from 22 patients. Of these patients, 9 had no acidosis, 9 had metabolic acidosis (plasma HCO3- < 22 mmol/l), and 4 had acidosis and received alkali therapy. We performed transcriptome analysis and immunohistochemistry for proteins involved in renal acid-base handling. RESULTS We found the expression of 40 transcripts significantly changed between kidneys from non-acidotic and acidotic patients. These genes are mostly involved in proximal tubule amino acid and lipid metabolism and energy homeostasis. Three transcripts were fully recovered by alkali therapy: the Kir4.2 K+-channel, an important regulator of proximal tubule HCO3--metabolism and transport, ACADSB and SHMT1, genes involved in beta-oxidation and methionine metabolism. Immunohistochemistry showed reduced staining for the proximal tubule NBCe1 HCO3- transporter in kidneys from acidotic patients that recovered with alkali therapy. In addition, the HCO3-exchanger pendrin was affected by acidosis and alkali therapy. CONCLUSIONS Metabolic acidosis in kidney transplant recipients is associated with alterations in the renal transcriptome that are partly restored by alkali therapy. Acid-base transport proteins mostly from proximal tubule were also affected by acidosis and alkali therapy suggesting that the downregulation of critical players contributes to metabolic acidosis in these patients.
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Affiliation(s)
- Pedro H Imenez Silva
- Institute of Physiology, University of Zurich, Zurich, Switzerland.,National Center of Competence in Research NCCR Kidney.CH, Switzerland
| | - Anna Wiegand
- Division of Nephrology, University Hospital Zurich, Zurich, Switzerland
| | - Arezoo Daryadel
- Institute of Physiology, University of Zurich, Zurich, Switzerland.,National Center of Competence in Research NCCR Kidney.CH, Switzerland
| | - Giancarlo Russo
- Functional Genomics Center Zürich, University of Zürich and ETH Zürich, Zürich, Switzerland
| | - Alexander Ritter
- Division of Nephrology, University Hospital Zurich, Zurich, Switzerland
| | - Ariana Gaspert
- Department of Pathology and Molecular Pathology, University Hospital Zurich, Zurich, Switzerland
| | - Rudolf P Wüthrich
- Division of Nephrology, University Hospital Zurich, Zurich, Switzerland
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland.,National Center of Competence in Research NCCR Kidney.CH, Switzerland
| | - Nilufar Mohebbi
- Division of Nephrology, University Hospital Zurich, Zurich, Switzerland
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Wagner CA. Coming out of the PiTs-novel strategies for controlling intestinal phosphate absorption in patients with CKD. Kidney Int 2021; 98:273-275. [PMID: 32709284 DOI: 10.1016/j.kint.2020.04.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 03/27/2020] [Accepted: 04/02/2020] [Indexed: 12/15/2022]
Abstract
The kidneys are the gatekeepers of phosphate balance, and loss of kidney function causes a profound disturbance of mineral metabolism. Patients with chronic kidney disease suffer from an excessive cardiovascular disease risk with a high morbidity and mortality. Current therapies aimed at reducing total phosphate body load are insufficient, and novel strategies are urgently needed. In this issue, Tsuboi and colleagues provide evidence for the use of a novel phosphate transporter inhibitor to reduce intestinal phosphate absorption.
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Affiliation(s)
- Carsten A Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland; National Center of Competence in Research (NCCR) Kidney Control of Homeostasis (Kidney.CH), University of Zurich, Zurich, Switzerland.
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Pastor-Arroyo EM, Rodriguez JMM, Pellegrini G, Bettoni C, Levi M, Hernando N, Wagner CA. Constitutive depletion of Slc34a2/NaPi-IIb in rats causes perinatal mortality. Sci Rep 2021; 11:7943. [PMID: 33846411 PMCID: PMC8042035 DOI: 10.1038/s41598-021-86874-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 03/15/2021] [Indexed: 11/23/2022] Open
Abstract
Absorption of dietary phosphate (Pi) across intestinal epithelia is a regulated process mediated by transcellular and paracellular pathways. Although hyperphosphatemia is a risk factor for the development of cardiovascular disease, the amount of ingested Pi in a typical Western diet is above physiological needs. While blocking intestinal absorption has been suggested as a therapeutic approach to prevent hyperphosphatemia, a complete picture regarding the identity and regulation of the mechanism(s) responsible for intestinal absorption of Pi is missing. The Na+/Pi cotransporter NaPi-IIb is a secondary active transporter encoded by the Slc34a2 gene. This transporter has a wide tissue distribution and within the intestinal tract is located at the apical membrane of epithelial cells. Based on mouse models deficient in NaPi-IIb, this cotransporter is assumed to mediate the bulk of active intestinal absorption of Pi. However, whether or not this is also applicable to humans is unknown, since human patients with inactivating mutations in SLC34A2 have not been reported to suffer from Pi depletion. Thus, mice may not be the most appropriate experimental model for the translation of intestinal Pi handling to humans. Here, we describe the generation of a rat model with Crispr/Cas-driven constitutive depletion of Slc34a2. Slc34a2 heterozygous rats were indistinguishable from wild type animals under standard dietary conditions as well as upon 3 days feeding on low Pi. However, unlike in humans, homozygosity resulted in perinatal lethality.
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Affiliation(s)
- Eva Maria Pastor-Arroyo
- Institute of Physiology, University of Zürich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Josep M Monné Rodriguez
- Laboratory for Animal Model Pathology (LAMP), Institute of Veterinary Pathology, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 268, 8057, Zurich, Switzerland
| | - Giovanni Pellegrini
- Laboratory for Animal Model Pathology (LAMP), Institute of Veterinary Pathology, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 268, 8057, Zurich, Switzerland
| | - Carla Bettoni
- Institute of Physiology, University of Zürich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Moshe Levi
- Department of Biochemistry and Molecular and Cellular Biology, Georgetown University, Washington, DC, USA
| | - Nati Hernando
- Institute of Physiology, University of Zürich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.
| | - Carsten A Wagner
- Institute of Physiology, University of Zürich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.
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Egli-Spichtig D, Zhang MYH, Li A, Pastor Arroyo EM, Hernando N, Wagner CA, Chang W, Perwad F. Renal Dnase1 expression is regulated by FGF23 but loss of Dnase1 does not alter renal phosphate handling. Sci Rep 2021; 11:6175. [PMID: 33731726 PMCID: PMC7969776 DOI: 10.1038/s41598-021-84735-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 02/02/2021] [Indexed: 11/16/2022] Open
Abstract
Fibroblast growth factor 23 (FGF23) is a bone-derived endocrine hormone that regulates phosphate and vitamin D metabolism. In models of FGF23 excess, renal deoxyribonuclease 1 (Dnase1) mRNA expression is downregulated. Dnase-1 is an endonuclease which binds monomeric actin. We investigated whether FGF23 suppresses renal Dnase-1 expression to facilitate endocytic retrieval of renal sodium dependent phosphate co-transporters (NaPi-IIa/c) from the brush border membrane by promoting actin polymerization. We showed that wild type mice on low phosphate diet and Fgf23−/− mice with hyperphosphatemia have increased renal Dnase1 mRNA expression while in Hyp mice with FGF23 excess and hypophosphatemia, Dnase1 mRNA expression is decreased. Administration of FGF23 in wild type and Fgf23−/− mice lowered Dnase1 expression. Taken together, our data shows that Dnase1 is regulated by FGF23. In 6-week-old Dnase1−/− mice, plasma phosphate and renal NaPi-IIa protein were significantly lower compared to wild-type mice. However, these changes were transient, normalized by 12 weeks of age and had no impact on bone morphology. Adaptation to low and high phosphate diet were similar in Dnase1−/− and Dnase1+/+ mice, and loss of Dnase1 gene expression did not rescue hyperphosphatemia in Fgf23−/− mice. We conclude that Dnase-1 does not mediate FGF23-induced inhibition of renal tubular phosphate reabsorption.
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Affiliation(s)
- Daniela Egli-Spichtig
- Division of Nephrology, Department of Pediatrics, University of California San Francisco, San Francisco, USA
| | - Martin Y H Zhang
- Division of Nephrology, Department of Pediatrics, University of California San Francisco, San Francisco, USA
| | - Alfred Li
- Department of Medicine, San Francisco Veterans Affairs Medical Center (VAMC), University of California San Francisco, San Francisco, USA
| | - Eva Maria Pastor Arroyo
- Institute of Physiology, University of Zurich, Zurich Switzerland and National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland
| | - Nati Hernando
- Institute of Physiology, University of Zurich, Zurich Switzerland and National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich, Zurich Switzerland and National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland
| | - Wenhan Chang
- Department of Medicine, San Francisco Veterans Affairs Medical Center (VAMC), University of California San Francisco, San Francisco, USA
| | - Farzana Perwad
- Division of Nephrology, Department of Pediatrics, University of California San Francisco, San Francisco, USA. .,Children's Renal Center, University of California San Francisco, 550, 16th Street, 5th Floor, MH-5351, San Francisco, CA, 94143-3214, USA.
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Ugrica M, Bettoni C, Bourgeois S, Daryadel A, Pastor-Arroyo EM, Gehring N, Hernando N, Wagner CA, Rubio-Aliaga I. A chronic high phosphate intake in mice is detrimental for bone health without major renal alterations. Nephrol Dial Transplant 2021; 36:gfab015. [PMID: 33515264 DOI: 10.1093/ndt/gfab015] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Phosphate intake has increased in the last decades due to a higher consumption of processed foods. This higher intake is detrimental for patients with chronic kidney disease, increasing mortality and cardiovascular disease risk and accelerating kidney dysfunction. Whether a chronic high phosphate diet is also detrimental for the healthy population is still under debate. METHODS We fed healthy mature adult mice over a period of one year with either a high (1.2% w/w) or a standard (0.6% w/w) phosphate diet, and investigated the impact of a high phosphate diet on mineral homeostasis, kidney function and bone health. RESULTS The high phosphate diet increased plasma phosphate, parathyroid hormone (PTH) and calcitriol levels, with no change in fibroblast growth factor 23 levels. Urinary phosphate, calcium and ammonium excretion were increased. Measured glomerular filtration rate was apparently unaffected, while blood urea was lower and urea clearance was higher in animals fed the high phosphate diet. No change was observed in plasma creatinine levels. Blood and urinary pH were more acidic paralleled by higher bone resorption observed in animals fed a high phosphate diet. Total and cortical bone mineral density was lower in animals fed a high phosphate diet and this effect is independent of the higher PTH levels observed. CONCLUSIONS A chronic high phosphate intake did not cause major renal alterations, but affected negatively bone health, increasing bone resorption and decreasing bone mineral density.
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Affiliation(s)
- Marko Ugrica
- Institute of Physiology, University of Zurich, and National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland
| | - Carla Bettoni
- Institute of Physiology, University of Zurich, and National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland
| | - Soline Bourgeois
- Institute of Physiology, University of Zurich, and National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland
| | - Arezoo Daryadel
- Institute of Physiology, University of Zurich, and National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland
| | - Eva-Maria Pastor-Arroyo
- Institute of Physiology, University of Zurich, and National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland
| | - Nicole Gehring
- Institute of Physiology, University of Zurich, and National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland
| | - Nati Hernando
- Institute of Physiology, University of Zurich, and National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich, and National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland
| | - Isabel Rubio-Aliaga
- Institute of Physiology, University of Zurich, and National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland
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Daryadel A, Ruiz PA, Gehring N, Stojanovic D, Ugrica M, Bettoni C, Sabrautzki S, Pastor‐Arroyo E, Frey‐Wagner I, Lorenz‐Depiereux B, Strom TM, Angelis MH, Rogler G, Wagner CA, Rubio‐Aliaga I. Systemic Jak1 activation provokes hepatic inflammation and imbalanced FGF23 production and cleavage. FASEB J 2021; 35:e21302. [DOI: 10.1096/fj.202002113r] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 12/08/2020] [Accepted: 12/09/2020] [Indexed: 12/24/2022]
Affiliation(s)
- Arezoo Daryadel
- Institute of Physiology University of Zurich (UZH), and National Center of Competence in Research NCCR Kidney.CH Zurich Switzerland
| | - Pedro A. Ruiz
- Department of Gastroenterology and Hepatology University Hospital of Zurich, University of Zurich Zurich Switzerland
| | - Nicole Gehring
- Institute of Physiology University of Zurich (UZH), and National Center of Competence in Research NCCR Kidney.CH Zurich Switzerland
| | - Dragana Stojanovic
- Institute of Physiology University of Zurich (UZH), and National Center of Competence in Research NCCR Kidney.CH Zurich Switzerland
| | - Marko Ugrica
- Institute of Physiology University of Zurich (UZH), and National Center of Competence in Research NCCR Kidney.CH Zurich Switzerland
| | - Carla Bettoni
- Institute of Physiology University of Zurich (UZH), and National Center of Competence in Research NCCR Kidney.CH Zurich Switzerland
| | - Sibylle Sabrautzki
- Institute of Experimental Genetics German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH) Neuherberg85764Germany
| | - Eva‐Maria Pastor‐Arroyo
- Institute of Physiology University of Zurich (UZH), and National Center of Competence in Research NCCR Kidney.CH Zurich Switzerland
| | - Isabelle Frey‐Wagner
- Department of Gastroenterology and Hepatology University Hospital of Zurich, University of Zurich Zurich Switzerland
| | - Bettina Lorenz‐Depiereux
- Institute of Human Genetics, Helmholtz Zentrum München German Research Center for Environmental Health (GmbH) Neuherberg Germany
| | - Tim M. Strom
- Institut für Humangenetik Klinikum rechts der Isar der Technischen Universität München München Germany
| | - Martin Hrabě Angelis
- Institute of Experimental Genetics German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH) Neuherberg85764Germany
- Lehrstuhl für Experimentelle Genetik Technische Universität München Freising‐Weihenstephan Germany
- Member of German Center for Diabetes Research (DZD) Neuherberg Germany
| | - Gerhard Rogler
- Department of Gastroenterology and Hepatology University Hospital of Zurich, University of Zurich Zurich Switzerland
| | - Carsten A. Wagner
- Institute of Physiology University of Zurich (UZH), and National Center of Competence in Research NCCR Kidney.CH Zurich Switzerland
| | - Isabel Rubio‐Aliaga
- Institute of Physiology University of Zurich (UZH), and National Center of Competence in Research NCCR Kidney.CH Zurich Switzerland
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Wagner CA. Etiopathogenic factors of urolithiasis. ARCH ESP UROL 2021; 74:16-23. [PMID: 33459618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
INTRODUCTION Kidney stone disease affects 1 in 10 persons at least once per life-time worldwide, in 2% the disease is recurrent. For the individual stone disease can be painful and lead even to chronic kidney disease, while the costs for the health system and economy can be very high. Thus, factors causing stone disease need to be identified in order to prevent or reduce the incidence of disease. AIM This review will discuss major risk factors contributing to stone disease with special emphasis on genetic and dietary risk factors. RESULTS: Stone disease is multifactorial with a strong genetic component, gender-specific risks and prevalence, and a modifiable contribution of nutrition. The different factors contributing to the risk for developing stones are discussed. DISCUSSION Urolithiasis is a frequent disorder affecting almost 10% of the population with a high risk of recurrence. Treatment and prevention have to be tailored to the individual causes of disease and require an assessment of underlying predispositions and interacting modifiable environmental factors.
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Affiliation(s)
- Carsten A Wagner
- Institute of Physiology. University of Zurich. Zurich. Switzerland. National Center of Competence in Research NCCR Kidney. CH. Switzerland. European Association of Urology. Section of Urolithiasis (EULIS)
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Hernando N, Pastor-Arroyo EM, Marks J, Schnitzbauer U, Knöpfel T, Bürki M, Bettoni C, Wagner CA. 1,25(OH) 2 vitamin D 3 stimulates active phosphate transport but not paracellular phosphate absorption in mouse intestine. J Physiol 2020; 599:1131-1150. [PMID: 33200827 DOI: 10.1113/jp280345] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 11/02/2020] [Indexed: 12/19/2022] Open
Abstract
KEY POINTS Intestinal absorption of phosphate proceeds via an active/transcellular route mostly mediated by NaPi-IIb/Slc34a2 and a poorly characterized passive/paracellular pathway. Intestinal phosphate absorption and expression of NaPi-IIb are stimulated by 1,25(OH)2 vitamin D3 but whether NaPi-IIb is the only target under hormonal control remains unknown. We report that administration of 1,25(OH)2 vitamin D3 to wild-type mice resulted in the expected increase in active transport of phosphate in jejunum, without changing paracellular fluxes. Instead, the same treatment failed to alter phosphate transport in intestinal-depleted Slc34a2-deficient mice. In both genotypes, 1,25(OH)2 vitamin D3 induced similar hyperphosphaturic responses and changes in the plasma levels of FGF23 and PTH. While urinary phosphate loss induced by administration of 1,25(OH)2 vitamin D3 did not alter plasma phosphate, further studies should investigate whether chronic administration would lead to phosphate imbalance in mice with reduced active intestinal absorption. ABSTRACT Intestinal absorption of phosphate is stimulated by 1,25(OH)2 vitamin D3. At least two distinct mechanisms underlie phosphate absorption in the gut, an active transcellular transport requiring the Na+ /phosphate cotransporter NaPi-IIb/Slc34a2, and a poorly characterized paracellular passive pathway. 1,25(OH)2 vitamin D3 stimulates NaPi-IIb expression and function, and loss of NaPi-IIb reduces intestinal phosphate absorption. However, it is remains unknown whether NaPi-IIb is the only target for hormonal regulation by 1,25(OH)2 vitamin D3 . Here we compared the effects of intraperitoneal administration of 1,25(OH)2 vitamin D3 (2 days, once per day) in wild-type and intestinal-specific Slc34a2-deficient mice, and analysed trans- vs. paracellular routes of phosphate absorption. We found that treatment stimulated active transport of phosphate only in jejunum of wild-type mice, though NaPi-IIb protein expression was upregulated in jejunum and ileum. In contrast, 1,25(OH)2 vitamin D3 administration had no effect in Slc34a2-deficient mice, suggesting that the hormone specifically regulates NaPi-IIb expression. In both groups, 1,25(OH)2 vitamin D3 elicited the expected increase of plasma fibroblast growth factor 23 (FGF23) and reduction of parathyroid hormone (PTH). Treatment resulted in hyperphosphaturia (and hypercalciuria) in both genotypes, though mice remained normophosphataemic. While increased intestinal absorption and higher FGF23 can trigger the hyperphosphaturic response in wild types, only higher FGF23 can explain the renal response in Slc34a2-deficient mice. Thus, 1,25(OH)2 vitamin D3 stimulates intestinal phosphate absorption by acting on the active transcellular pathway mostly mediated by NaPi-IIb while the paracellular pathway appears not to be affected.
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Affiliation(s)
- Nati Hernando
- Institute of Physiology, University of Zürich, Zürich, Switzerland
| | | | - Joanne Marks
- University College London, Gower St, London, WC1E 6BT, UK
| | - Udo Schnitzbauer
- Institute of Physiology, University of Zürich, Zürich, Switzerland
| | - Thomas Knöpfel
- Institute of Physiology, University of Zürich, Zürich, Switzerland
| | - Matthias Bürki
- Institute of Physiology, University of Zürich, Zürich, Switzerland
| | - Carla Bettoni
- Institute of Physiology, University of Zürich, Zürich, Switzerland
| | - Carsten A Wagner
- Institute of Physiology, University of Zürich, Zürich, Switzerland
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Chande S, Zeiss C, Vézier J, Chavkin NW, Hernando N, Giachelli CM, Wagner CA, Beck L, Beck-Cormier S, Bergwitz C. Ablation of Slc20a1/PitT1 and Slc20a2/PiT2 in mice in the osteogenic lineage causes dentin dysplasia and formation of ectopic enamel islands. Bone Rep 2020. [DOI: 10.1016/j.bonr.2020.100648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Pastor‐Arroyo EM, Knöpfel T, Imenez Silva PH, Schnitzbauer U, Poncet N, Biber J, Wagner CA, Hernando N. Intestinal epithelial ablation of Pit-2/Slc20a2 in mice leads to sustained elevation of vitamin D 3 upon dietary restriction of phosphate. Acta Physiol (Oxf) 2020; 230:e13526. [PMID: 32564464 DOI: 10.1111/apha.13526] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 05/27/2020] [Accepted: 06/15/2020] [Indexed: 12/31/2022]
Abstract
AIM Several Na+ -dependent phosphate cotransporters, namely NaPi-IIb/SLC34A2, Pit-1/SLC20A1 and Pit-2/SLC20A2, are expressed at the apical membrane of enterocytes but their contribution to active absorption of phosphate is unclear. The aim of this study was to compare their pattern of mRNA expression along the small and large intestine and to analyse the effect of intestinal depletion of Pit-2 on phosphate homeostasis. METHODS Intestinal epithelial Pit-2-deficient mice were generated by crossing floxed Pit-2 with villin-Cre mice. Mice were fed 2 weeks standard or low phosphate diets. Stool, urine, plasma and intestinal and renal tissue were collected. Concentration of electrolytes and hormones, expression of mRNAs and proteins and intestinal transport of tracers were analysed. RESULTS Intestinal mRNA expression of NaPi-IIb and Pit-1 is segment-specific, whereas the abundance of Pit-2 mRNA is more homogeneous. In ileum, NaPi-IIb mRNA expression is restricted to enterocytes, whereas Pit-2 mRNA is found in epithelial and non-epithelial cells. Overall, their mRNA expression is not regulated by dietary phosphate. The absence of Pit-2 from intestinal epithelial cells does not affect systemic phosphate homeostasis under normal dietary conditions. However, in response to dietary phosphate restriction, Pit-2-deficient mice showed exacerbated hypercalciuria and sustained elevation of 1,25(OH)2 vitamin D3 . CONCLUSIONS In mice, the intestinal Na+ /phosphate cotransporters are not coexpressed in all segments. NaPi-IIb but not Pit-2 mRNA is restricted to epithelial cells. Intestinal epithelial Pit-2 does not contribute significantly to absorption of phosphate under normal dietary conditions. However, it may play a more significant role upon dietary phosphate restriction.
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Affiliation(s)
| | - Thomas Knöpfel
- Institute of Physiology University of Zürich Zürich Switzerland
| | | | | | - Nadège Poncet
- Institute of Physiology University of Zürich Zürich Switzerland
| | - Jürg Biber
- Institute of Physiology University of Zürich Zürich Switzerland
| | | | - Nati Hernando
- Institute of Physiology University of Zürich Zürich Switzerland
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49
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Zoccali C, Vanholder R, Wagner CA, Anders HJ, Blankestijn PJ, Bruchfeld A, Capasso G, Cozzolino M, Dekker FW, Fliser D, Fouque D, Gansevoort RT, Goumenos D, Jager KJ, Massy ZA, Oostrom TAJ, Rychlık I, Soler MJ, Stevens K, Spasovski G, Wanner C. Funding kidney research as a public health priority: challenges and opportunities. Nephrol Dial Transplant 2020; 37:21-28. [PMID: 32888017 DOI: 10.1093/ndt/gfaa163] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Indexed: 01/03/2023] Open
Abstract
Medical societies have a social responsibility to disseminate knowledge and inform health authorities on threats to public health posed by various diseases. Advocacy for health protection programmes and for medical research funding is now embedded into the missions of most scientific societies. To promote kidney research funding in Europe, the European Renal Association - European Dialysis and Transplant Association (ERA-EDTA), rather than acting as an individual society advocating for the fight against kidney disease, has actively helped to create an alliance of national associations centred on kidney diseases, the European Kidney Health Alliance (EKHA), and joined the Biomedical Alliance (BMA). The ERA-EDTA is fully committed to supporting its working groups (WGs) and consortia of its members to allow them to produce valuable kidney research. The framing and formalization of projects, and the regulatory issues related to submission to the European Commission, are complex. To help WGs to gain expert advice from agencies with specific know-how, the ERA-EDTA has adopted a competitive approach. The best research projects proposed by WGs and consortia of other European investigators will receive seed funding to cover the costs of consultancy by expert agencies. Via its broader platforms, the EKHA and the BMA, the ERA-EDTA will strive towards broader recognition of kidney disease and related clusters of non-communicable diseases, by European and national agencies, as major threats to the qualities of life of their populations and their economies.
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Affiliation(s)
| | - Raymond Vanholder
- Department of Internal Medicine, Ghent University Hospital, Ghent, Belgium.,European Kidney Health Alliance (EKHA), Brussels, Belgium
| | - Carsten A Wagner
- Institute of Physiology, Switzerland and National Center of Competence in Research NCCR Kidney, University of Zurich, Zurich, Switzerland
| | - Hans-Joachim Anders
- Division of Nephrology, Medizinische Klinik und Poliklinik IV, Klinikum der Universität, Munich, Germany
| | - Peter J Blankestijn
- Nephrology Section Department of Nephrology, University Medical Center, Utrecht, The Netherlands
| | - Annette Bruchfeld
- Department of Renal Medicine, Karolinska University Hospital, Stockholm, Sweden
| | - Giovambattista Capasso
- Department of Translational Medical Sciences, University Campania 'Luigi Vanvitelli', Naples, Italy
| | - Mario Cozzolino
- Renal Division, ASST Santi Paolo E Carlo, Department of Health Sciences, University of Milan, Milan, Italy
| | - Friedo W Dekker
- Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Danilo Fliser
- Internal Medicine IV, Renal and Hypertensive Diseases, Saarland University Medical Centre, Homburg/Saar, Germany
| | - Denis Fouque
- Department of Nephrology, Dialysis, Nutrition, Centre Hospitalier Lyon Sud, Pierre Bénite Cedex, France
| | - Ron T Gansevoort
- Department of Nephrology, University Medical Centre Groningen, University Hospital Groningen, Groningen, The Netherlands
| | - Dimitrios Goumenos
- Department of Nephrology and Renal Transplantation, Patras University Hospital, Patras, Greece
| | - Kitty J Jager
- Department of Medical Informatics, Academic Medical Center, Amsterdam Public Health Research Institute, University of Amsterdam, Amsterdam, The Netherlands
| | - Ziad A Massy
- Division of Nephrology, Ambroise Paré University Hospital, APHP, Boulogne Billancourt/Paris and Centre for Research in Epidemiology and Population Health (CESP), INSERM UMRS 1018 Team 5, University Paris-Saclay, and University Versailles Saint Quentin, Villejuif, France
| | | | - Ivan Rychlık
- 1st Department of Internal Medicine, Third Faculty of Medicine, Charles University, Prague, Czechia
| | - Maria Jose Soler
- Nephrology Department, Hospital Universitari Vall d'Hebron, Nephrology Research Group, Vall d'Hebron Research Institute (VHIR), Barcelona, Spain
| | - Kate Stevens
- Glasgow Renal and Transplant Unit, Queen Elizabeth University Hospital, Glasgow, UK
| | - Goce Spasovski
- Department of Nephrology, Medical Faculty, University of Skopje, Skopje, Northern Republic of Macedonia
| | - Christoph Wanner
- Division of Nephrology, University of Würzburg, Würzburg, Germany
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50
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Manian N, Wagner CA, Placzek H, Darby BA, Kaiser TJ, Rog DJ. Relationship between intervention dosage and success of resource connections in a social needs intervention. Public Health 2020; 185:324-331. [PMID: 32726729 DOI: 10.1016/j.puhe.2020.05.058] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 03/02/2020] [Accepted: 05/29/2020] [Indexed: 01/09/2023]
Abstract
OBJECTIVES Social needs interventions in medical settings aim to mitigate the effects of adverse social circumstances on health outcomes by connecting vulnerable patients with resources. This study examined the relationship between intervention dosage and the success of resource connections using data from a social needs intervention in multiple clinical settings across the US. STUDY DESIGN The intervention uses a case management approach to connect patients with unmet needs to resources and services in the community. Intervention dosage was conceptualized as the number of contacts between the navigator and the patient, categorized as direct contact (phone vs. in person) and indirect contact (initiated by the navigator vs. patient). Success of the intervention was conceptualized as 'none,' 'partial,' or 'optimal' for each patient, based on the number of social needs the resource connections addressed. METHODS Administrative data were extracted for 38,404 unique patients who screened positive for unmet resource needs between 2012 and 2017. Owing to the large sample size, statistical corrections were made to reduce type I error. RESULTS Multinomial logistic regression analyses showed that higher intervention dosage was related to greater success of resource connections, after adjusting for the patient and site characteristics, and the number of needs (odds ratios ranged from 1.62 to 2.89). In-person contact, although received by only 25% of the patients, was associated with the highest probability of optimal success. CONCLUSIONS This study demonstrates a feasible way to conceptualize an intervention dose for a social needs intervention that uses a case management approach and has implications for how intervention delivery may improve success of resource connections.
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Affiliation(s)
- N Manian
- Westat, 1600 Research Blvd, Rockville, MD 20850, USA.
| | - C A Wagner
- Westat, 1600 Research Blvd, Rockville, MD 20850, USA
| | - H Placzek
- Health Leads, 24 School St, Boston, MA 02108, USA
| | - B A Darby
- Health Leads, 24 School St, Boston, MA 02108, USA
| | - T J Kaiser
- Health Leads, 24 School St, Boston, MA 02108, USA
| | - D J Rog
- Westat, 1600 Research Blvd, Rockville, MD 20850, USA
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