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Jung HJ, Pham TD, Su XT, Grigore TV, Hoenderop JG, Olauson H, Wall SM, Ellison DH, Welling PA, Al-Qusairi L. Klotho is highly expressed in the chief sites of regulated potassium secretion, and it is stimulated by potassium intake. Sci Rep 2024; 14:10740. [PMID: 38729987 PMCID: PMC11087591 DOI: 10.1038/s41598-024-61481-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 05/06/2024] [Indexed: 05/12/2024] Open
Abstract
Klotho regulates many pathways in the aging process, but it remains unclear how it is physiologically regulated. Because Klotho is synthesized, cleaved, and released from the kidney; activates the chief urinary K+ secretion channel (ROMK) and stimulates urinary K+ secretion, we explored if Klotho protein is regulated by dietary K+ and the potassium-regulatory hormone, Aldosterone. Klotho protein along the nephron was evaluated in humans and in wild-type (WT) mice; and in mice lacking components of Aldosterone signaling, including the Aldosterone-Synthase KO (AS-KO) and the Mineralocorticoid-Receptor KO (MR-KO) mice. We found the specific cells of the distal nephron in humans and mice that are chief sites of regulated K+ secretion have the highest Klotho protein expression along the nephron. WT mice fed K+-rich diets increased Klotho expression in these cells. AS-KO mice exhibit normal Klotho under basal conditions but could not upregulate Klotho in response to high-K+ intake in the K+-secreting cells. Similarly, MR-KO mice exhibit decreased Klotho protein expression. Together, i) Klotho is highly expressed in the key sites of regulated K+ secretion in humans and mice, ii) In mice, K+-rich diets increase Klotho expression specifically in the potassium secretory cells of the distal nephron, iii) Aldosterone signaling is required for Klotho response to high K+ intake.
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Affiliation(s)
- Hyun Jun Jung
- Department of Nephrology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Truyen D Pham
- Department of Nephrology, Emory University School of Medicine, Atlanta, GA, USA
| | - Xiao-Tong Su
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, USA
| | - Teodora Veronica Grigore
- Department of Medical BioSciences, Radboud Research Institute for Medical Innovation, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Joost G Hoenderop
- Department of Medical BioSciences, Radboud Research Institute for Medical Innovation, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Hannes Olauson
- Division of Renal Medicine, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden
| | - Susan M Wall
- Department of Nephrology, Emory University School of Medicine, Atlanta, GA, USA
| | - David H Ellison
- Division of Nephrology and Hypertension, Department of Medicine, Oregon Health and Science University, Portland, USA
| | - Paul A Welling
- Department of Nephrology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Lama Al-Qusairi
- Department of Nephrology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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2
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Raphael KL, Katz R, Larive B, Kendrick C, Isakova T, Sprague S, Wolf M, Raj DS, Fried LF, Gassman J, Hoofnagle A, Cheung AK, Ix JH. Oral Sodium Bicarbonate and Bone Turnover in CKD: A Secondary Analysis of the BASE Pilot Trial. J Am Soc Nephrol 2024; 35:57-65. [PMID: 38170601 PMCID: PMC10786609 DOI: 10.1681/asn.0000000000000264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 10/18/2023] [Indexed: 01/05/2024] Open
Abstract
SIGNIFICANCE STATEMENT In CKD, metabolic acidosis is commonly treated with alkali in the hope that it will improve bone health. In a post hoc analysis of the Bicarbonate Administration to Stabilize eGFR Pilot Trial, we investigated whether sodium bicarbonate affects serum levels of bone turnover markers and other hormones related to bone health in individuals with CKD who have normal to slightly reduced total CO2 (20-28 mEq/L). Sodium bicarbonate increased serum levels of α-klotho but had no significant effect on other bone health markers, including intact fibroblast growth factor-23 (iFGF-23), intact parathyroid hormone (iPTH), and bone-specific alkaline phosphatase (B-SAP). Further study is needed to determine the effect of bicarbonate administration on clinical aspects of bone health. BACKGROUND Treatment with alkali has been hypothesized to improve bone health in CKD by mitigating adverse effects of acid on bone mineral. We investigated the effect of treatment with sodium bicarbonate on bone turnover markers and other factors related to bone metabolism in CKD. METHODS This is a post hoc analysis of the Bicarbonate Administration to Stabilize eGFR Pilot Trial in which 194 individuals with CKD and serum total CO2 20-28 mEq/L were randomly assigned to placebo or one of two doses of sodium bicarbonate (0.5 or 0.8 mEq/kg lean body weight per day) for 28 weeks. The following serum measurements were performed at baseline, week 12, and week 28: B-SAP, c-telopeptide, procollagen type I intact N-terminal propeptide, iPTH, iFGF-23, soluble klotho, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, and tartrate-resistant acid phosphatase 5b. The difference (sodium bicarbonate versus placebo) in mean change of each bone biomarker from baseline was determined using linear mixed models. RESULTS One hundred sixty-eight participants submitted samples for post hoc investigations. Mean eGFR was 37±10 ml/min per 1.73 m2 and mean total CO2 was 24±3 mEq/L at baseline. Sodium bicarbonate induced a dose-dependent increase in soluble klotho levels compared with placebo. There was no significant effect of treatment with either dose of sodium bicarbonate on any of the other bone biomarkers, including iFGF-23, iPTH, and B-SAP. Effects on bone biomarkers were similar in those with baseline serum total CO2 <24 mEq/L compared with those with total CO2 ≥24 mEq/L. CONCLUSIONS In this pilot trial of individuals with CKD and total CO2 20-28 mEq/L, sodium bicarbonate treatment increased serum klotho levels but did not affect other bone health markers over 28 weeks. CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER ClinicalTrials.gov, NCT02521181.
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Affiliation(s)
- Kalani L. Raphael
- University of Utah Health and VA Salt Lake City Health Care System, Salt Lake City, Utah
| | - Ronit Katz
- Department of Obstetrics & Gynecology, University of Washington, Seattle, Washington
| | | | | | - Tamara Isakova
- Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Stuart Sprague
- Division of Nephrology & Hypertension, Northshore University Health System-University of Chicago, Evanston, Illinois
| | - Myles Wolf
- Division of Nephrology, Department of Medicine, Duke Clinical Research Institute, Duke University School of Medicine, Durham, North Carolina
| | - Dominic S. Raj
- George Washington University School of Medicine, Washington, DC
| | - Linda F. Fried
- University of Pittsburgh and VA Pittsburgh Health Care System, Pittsburgh, Pennsylvania
| | | | - Andy Hoofnagle
- Department of Obstetrics & Gynecology, University of Washington, Seattle, Washington
| | - Alfred K. Cheung
- University of Utah Health and VA Salt Lake City Health Care System, Salt Lake City, Utah
| | - Joachim H. Ix
- University of California San Diego and VA San Diego Health Care System, San Diego, California
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3
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Zhang J, Zhang A. Relationships between serum Klotho concentrations and cognitive performance among older chronic kidney disease patients with albuminuria in NHANES 2011-2014. Front Endocrinol (Lausanne) 2023; 14:1215977. [PMID: 37560310 PMCID: PMC10407554 DOI: 10.3389/fendo.2023.1215977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 07/07/2023] [Indexed: 08/11/2023] Open
Abstract
Background The potential relationship between Klotho and cognitive function is limited and controversial. This study aimed to quantify the association of Klotho and cognitive impairment in chronic kidney disease (CKD) patients with albuminuria. Methods Serum Klotho was measured by enzyme-linked immunosorbent assay. Patients with urine albumin to creatinine ratio (UACR) > 30mg/g from the National Health and Nutrition Survey (NHANES) 2011-2014 were divided into 4 groups according to the quartile of Klotho. Cognitive function was examined using the Consortium to Establish a Registry for Alzheimer's Disease (CERAD), Digit Symbol Substitution Test (DSST), and Animal Fluency Test. The relationship between Klotho and cognitive function was analyzed by multivariable regression and subgroup analysis. Results Among 368 CKD patients with albuminuria, we found that Klotho was negatively associated with creatinine, and positively associated with hemoglobin, and estimated glomerular filtration rate. No significant linear relationship was showed between Klotho (as a continuous variable) and cognitive function. When regarded Klotho as a category variable, patients in the quartile 3 group were at a better cognitive performance for CEARD-word learning subset and DSST, especially in the CKD patients with 30 mg/g < UACR <300 mg/g, but not in participants with UACR > 300 mg/g. Conclusions The increased Klotho was associated with an increased cognitive function in CKD patients with microalbuminuria. Further studies are needed to demonstrate whether Klotho may be a beneficial biomarker of cognitive health and neurodegeneration.
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Affiliation(s)
- Jialing Zhang
- Department of Nephrology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Aihua Zhang
- Department of Nephrology, Xuanwu Hospital, Capital Medical University, Beijing, China
- The National Clinical Research Center for Geriatric Disease, Xuanwu Hospital, Capital Medical University, Beijing, China
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4
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Castillo RF. Pathophysiological Implications and Therapeutic Approach of Klotho in Chronic Kidney Disease. A Systematic Review. J Transl Med 2023:100178. [PMID: 37207706 DOI: 10.1016/j.labinv.2023.100178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 04/24/2023] [Accepted: 05/10/2023] [Indexed: 05/21/2023] Open
Abstract
The Klotho protein, known as an anti-aging protein, is expressed mainly in the kidney, and kidney disorders may contribute to disrupted expression of renal Klotho. The purpose of this systematic review was to determine if there are biological and nutraceutical therapies that increase the expression of Klotho and can help prevent complications associated with CKD. A systematic literature review was carried out through the consultation of PubMed, Scopus, and Web of Science. Records between the years 2012 and 2022 in Spanish and English were selected. Cross-sectional or prevalence and analytical studies were included that evaluated the effects of Klotho therapy. A total of 22 studies were identified after the critical reading of these selected studies. Three investigated the association between Klotho and growth factors; two evaluated the relationship between the concentration of Klotho and the type of fibrosis; three focused on the relationship between vascular calcifications and vitamin D; two assessed the relationship between Klotho and bicarbonate; two investigated the relationship between proteinuria and Klotho; one demonstrated the applicability of synthetic antibodies as a support for Klotho deficiency; one investigated Klotho hypermethylation as a renal biomarker; two investigated the relationship between proteinuria and Klotho; four linked Klotho as an early marker of CKD; one investigated Klotho levels in patients with autosomal dominant polycystic kidney disease. In conclusion, no study has addressed the comparison of these therapies in the context of their use with nutraceutical agents that raise the expression of Klotho.
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Affiliation(s)
- Rafael Fernandez Castillo
- Instituto de Investigación Biosanitaria ibs.Granada; Faculty of Health Sciences, University of Granada, 18071 Granada, Spain.
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5
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Yu LX, Li SS, Sha MY, Kong JW, Ye JM, Liu QF. The controversy of klotho as a potential biomarker in chronic kidney disease. Front Pharmacol 2022; 13:931746. [PMID: 36210812 PMCID: PMC9532967 DOI: 10.3389/fphar.2022.931746] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 08/30/2022] [Indexed: 11/13/2022] Open
Abstract
Klotho is an identified longevity gene with beneficial pleiotropic effects on the kidney. Evidence shows that a decline in serum Klotho level occurs in early chronic kidney disease (CKD) and continues as CKD progresses. Klotho deficiency is associated with poor clinical outcomes and CKD mineral bone disorders (CKD-MBD). Klotho has been postulated as a candidate biomarker in the evaluation of CKD. However, the evidence for the clinical significance of the relationship between Klotho and kidney function, CKD stage, adverse kidney and/or non-kidney outcomes, and CKD-MBD remains inconsistent and in some areas, contradictory. Therefore, there is uncertainty as to whether Klotho is a potential biomarker in CKD; a general consensus regarding the clinical significance of Klotho in CKD has not been reached, and there is limited evidence synthesis in this area. To address this, we have systematically assessed the areas of controversy, focusing on the inconsistencies in the evidence base. We used a PICOM strategy to search for relevant studies and the Newcastle–Ottawa Scale scoring to evaluate included publications. We reviewed the inconsistent clinical findings based on the relationship of Klotho with CKD stage, kidney and/or non-kidney adverse outcomes, and CKD-MBD in human studies. Subsequently, we assessed the underlying sources of the controversies and highlighted future directions to resolve these inconsistencies and clarify whether Klotho has a role as a biomarker in clinical practice in CKD.
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Affiliation(s)
- Li-Xia Yu
- Department of Nephrology, Affiliated Kunshan Hospital of Jiangsu University, Kunshan, China
| | - Sha-Sha Li
- Clinical Research and Lab Center, Affiliated Kunshan Hospital of Jiangsu University, Kunshan, China
| | - Min-Yue Sha
- Department of Nephrology, Affiliated Kunshan Hospital of Jiangsu University, Kunshan, China
| | - Jia-Wei Kong
- Department of Nephrology, Affiliated Kunshan Hospital of Jiangsu University, Kunshan, China
| | - Jian-Ming Ye
- Department of Nephrology, Affiliated Kunshan Hospital of Jiangsu University, Kunshan, China
- *Correspondence: Jian-Ming Ye, ; Qi-Feng Liu,
| | - Qi-Feng Liu
- Department of Nephrology, Affiliated Kunshan Hospital of Jiangsu University, Kunshan, China
- *Correspondence: Jian-Ming Ye, ; Qi-Feng Liu,
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Infante B, Franzin R, Madio D, Calvaruso M, Maiorano A, Sangregorio F, Netti GS, Ranieri E, Gesualdo L, Castellano G, Stallone G. Molecular Mechanisms of AKI in the Elderly: From Animal Models to Therapeutic Intervention. J Clin Med 2020; 9:jcm9082574. [PMID: 32784471 PMCID: PMC7464895 DOI: 10.3390/jcm9082574] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 07/21/2020] [Accepted: 08/05/2020] [Indexed: 12/17/2022] Open
Abstract
Acute kidney injury (AKI), a critical syndrome characterized by a sudden reduction of renal function, is a common disorder among elderly patients particularly in Intensive Care Unit (ICU). AKI is closely associated with both short- and long-term mortality and length of hospital stay and is considered a predictor of chronic kidney disease (CKD). Specific hemodynamic, metabolic, and molecular changes lead to increased susceptibility to injury in the aged kidney; therefore, certain causes of AKI such as the prerenal reduction in renal perfusion or vascular obstructive conditions are more common in the elderly; moreover, AKI is often multifactorial and iatrogenic. Older patients present several comorbidities (diabetes, hypertension, heart failure) and are exposed to multiple medical interventions such as the use of nephrotoxic contrasts media and medications, which can also trigger AKI. Considering the emerging relevance of this condition, prevention and treatment of AKI in the elderly should be crucial in the internist and emergency setting. This review article summarizes the incidence, the risk factors, the pathophysiology, the molecular mechanisms and the strategies of prevention and treatment of AKI in elderly patients.
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Affiliation(s)
- Barbara Infante
- Nephrology, Dialysis and Transplantation Unit, Department of Medical and Surgical Sciences, University of Foggia, Viale Pinto Luigi 251, 71122 Foggia, Italy; (B.I.); (D.M.); (A.M.); (F.S.); (G.S.)
| | - Rossana Franzin
- Nephrology, Dialysis and Transplantation Unit, Department of Emergency and Organ Transplantation, University of Bari, 70124 Bari, Italy; (R.F.); (L.G.)
| | - Desirèe Madio
- Nephrology, Dialysis and Transplantation Unit, Department of Medical and Surgical Sciences, University of Foggia, Viale Pinto Luigi 251, 71122 Foggia, Italy; (B.I.); (D.M.); (A.M.); (F.S.); (G.S.)
| | - Martina Calvaruso
- Nephrology, Dialysis and Transplantation Unit, Department of Biomedical Sciences, University of Foggia, 71122 Foggia, Italy;
| | - Annamaria Maiorano
- Nephrology, Dialysis and Transplantation Unit, Department of Medical and Surgical Sciences, University of Foggia, Viale Pinto Luigi 251, 71122 Foggia, Italy; (B.I.); (D.M.); (A.M.); (F.S.); (G.S.)
| | - Fabio Sangregorio
- Nephrology, Dialysis and Transplantation Unit, Department of Medical and Surgical Sciences, University of Foggia, Viale Pinto Luigi 251, 71122 Foggia, Italy; (B.I.); (D.M.); (A.M.); (F.S.); (G.S.)
| | - Giuseppe Stefano Netti
- Clinical Pathology, Department of Surgical and Medical Sciences, University of Foggia, Viale Pinto Luigi 251, 71122 Foggia, Italy; (G.S.N.); (E.R.)
| | - Elena Ranieri
- Clinical Pathology, Department of Surgical and Medical Sciences, University of Foggia, Viale Pinto Luigi 251, 71122 Foggia, Italy; (G.S.N.); (E.R.)
| | - Loreto Gesualdo
- Nephrology, Dialysis and Transplantation Unit, Department of Emergency and Organ Transplantation, University of Bari, 70124 Bari, Italy; (R.F.); (L.G.)
| | - Giuseppe Castellano
- Nephrology, Dialysis and Transplantation Unit, Department of Medical and Surgical Sciences, University of Foggia, Viale Pinto Luigi 251, 71122 Foggia, Italy; (B.I.); (D.M.); (A.M.); (F.S.); (G.S.)
- Correspondence: ; Tel.: +39-088-173-2610; Fax: +39-088-173-6001
| | - Giovanni Stallone
- Nephrology, Dialysis and Transplantation Unit, Department of Medical and Surgical Sciences, University of Foggia, Viale Pinto Luigi 251, 71122 Foggia, Italy; (B.I.); (D.M.); (A.M.); (F.S.); (G.S.)
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de Seigneux S, Delitsikou V, Martin PY. The KNOW-CKD study: evidence for a link between proteinuria and alterations of mineral metabolism. Nephrol Dial Transplant 2020; 35:382-385. [PMID: 31039254 DOI: 10.1093/ndt/gfz083] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 03/27/2019] [Indexed: 02/07/2023] Open
Affiliation(s)
- Sophie de Seigneux
- Laboratory and Service of Nephrology, Department of Internal Medicine, University Hospital of Geneva, Geneva, Switzerland.,Department of Cell Physiology and Metabolism, University Hospital of Geneva, Geneva, Switzerland
| | - Vasiliki Delitsikou
- Laboratory and Service of Nephrology, Department of Internal Medicine, University Hospital of Geneva, Geneva, Switzerland.,Department of Cell Physiology and Metabolism, University Hospital of Geneva, Geneva, Switzerland
| | - Pierre-Yves Martin
- Laboratory and Service of Nephrology, Department of Internal Medicine, University Hospital of Geneva, Geneva, Switzerland.,Department of Cell Physiology and Metabolism, University Hospital of Geneva, Geneva, Switzerland
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Delitsikou V, Jarad G, Rajaram RD, Ino F, Rutkowski JM, Chen CD, Santos CXC, Scherer PE, Abraham CR, Shah AM, Feraille E, Miner JH, de Seigneux S. Klotho regulation by albuminuria is dependent on ATF3 and endoplasmic reticulum stress. FASEB J 2019; 34:2087-2104. [PMID: 31907991 DOI: 10.1096/fj.201900893r] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 10/31/2019] [Accepted: 11/13/2019] [Indexed: 12/11/2022]
Abstract
Proteinuria is associated with renal function decline and cardiovascular mortality. This association may be attributed in part to alterations of Klotho expression induced by albuminuria, yet the underlying mechanisms are unclear. The presence of albumin decreased Klotho expression in the POD-ATTAC mouse model of proteinuric kidney disease as well as in kidney epithelial cell lines. This downregulation was related to both decreased Klotho transcription and diminished protein half-life, whereas cleavage by ADAM proteases was not modified. The regulation was albumin specific since it was neither observed in the analbuminemic Col4α3-/- Alport mice nor induced by exposure of kidney epithelial cells to purified immunoglobulins. Albumin induced features of ER stress in renal tubular cells with ATF3/ATF4 activation. ATF3 and ATF4 induction downregulated Klotho through altered transcription mediated by their binding on the Klotho promoter. Inhibiting ER stress with 4-PBA decreased the effect of albumin on Klotho protein levels without altering mRNA levels, thus mainly abrogating the increased protein degradation. Taken together, albuminuria decreases Klotho expression through increased protein degradation and decreased transcription mediated by ER stress induction. This implies that modulating ER stress may improve proteinuria-induced alterations of Klotho expression, and hence renal and extrarenal complications associated with Klotho loss.
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Affiliation(s)
- Vasiliki Delitsikou
- Department of Cell Physiology and Metabolism, Faculty of Medicine, CMU, University of Geneva, Geneva, Switzerland.,Laboratory of Nephrology, Department of Internal Medicine Specialties, HUG, Geneva, Switzerland
| | - George Jarad
- Division of Nephrology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri
| | - Renuga Devi Rajaram
- Department of Cell Physiology and Metabolism, Faculty of Medicine, CMU, University of Geneva, Geneva, Switzerland.,Laboratory of Nephrology, Department of Internal Medicine Specialties, HUG, Geneva, Switzerland
| | - Frédérique Ino
- Department of Cell Physiology and Metabolism, Faculty of Medicine, CMU, University of Geneva, Geneva, Switzerland.,Laboratory of Nephrology, Department of Internal Medicine Specialties, HUG, Geneva, Switzerland
| | - Joseph M Rutkowski
- Touchstone Diabetes Centre, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas.,Department of Medical Physiology, Texas A&M College of Medicine, College Station, Texas
| | - Ci-Di Chen
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts
| | - Celio X C Santos
- King's College London British Heart Foundation Centre of Excellence, School of Cardiovascular Medicine & Sciences, London, UK
| | - Philipp E Scherer
- Touchstone Diabetes Centre, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas
| | - Carmela R Abraham
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts
| | - Ajay M Shah
- King's College London British Heart Foundation Centre of Excellence, School of Cardiovascular Medicine & Sciences, London, UK
| | - Eric Feraille
- Department of Cell Physiology and Metabolism, Faculty of Medicine, CMU, University of Geneva, Geneva, Switzerland
| | - Jeffrey H Miner
- Division of Nephrology, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri
| | - Sophie de Seigneux
- Department of Cell Physiology and Metabolism, Faculty of Medicine, CMU, University of Geneva, Geneva, Switzerland.,Laboratory of Nephrology, Department of Internal Medicine Specialties, HUG, Geneva, Switzerland
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Fernandez-Fernandez B, Izquierdo MC, Valiño-Rivas L, Nastou D, Sanz AB, Ortiz A, Sanchez-Niño MD. Albumin downregulates Klotho in tubular cells. Nephrol Dial Transplant 2019; 33:1712-1722. [PMID: 29425318 DOI: 10.1093/ndt/gfx376] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Accepted: 12/18/2017] [Indexed: 12/17/2022] Open
Abstract
Background Kidney tubular cells are the main sources of Klotho, a protein with phosphaturic action. Genetic Klotho deficiency causes premature cardiovascular aging in mice. Human chronic kidney disease (CKD) is characterized by acquired Klotho deficiency. Despite the lack of uremic toxin accumulation, Category G1 CKD [(normal glomerular filtration rate (GFR)] is already associated with decreased Klotho and with premature cardiovascular aging. Methods We have explored whether albuminuria, a criterion to diagnose CKD when GFR is normal, may directly decrease Klotho expression in human CKD, preclinical models and cultured tubular cells. Results In a CKD cohort, albuminuria correlated with serum phosphate after adjustment for GFR, age and sex. In this regard, urinary Klotho was decreased in patients with pathological albuminuria but preserved GFR. Proteinuria induced in rats by puromycin aminonucleoside and in mice by albumin overload was associated with interstitial inflammation and reduced total kidney Klotho messenger ribonucleic acid (mRNA) expression. Western blot disclosed reduced kidney Klotho protein in proteinuric rats and mice and immunohistochemistry localized the reduced kidney Klotho expression to tubular cells in proteinuric animals. In cultured murine and human tubular cells, albumin directly decreased Klotho mRNA and protein expression. This was inhibited by trichostatin A, an inhibitor of histone deacetylases, but unlike cytokine-induced Klotho downregulation, not by inhibitors of nuclear factor kappa-light-chain-enhancer of activated B cells. Conclusions In conclusion, albumin directly decreases Klotho expression in cultured tubular cells. This may explain, or at least contribute to, the decrease in Klotho and promote fibroblast growth factor 23 resistance in early CKD categories, as observed in preclinical and clinical proteinuric kidney disease.
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Affiliation(s)
- Beatriz Fernandez-Fernandez
- Department of Nephrology, IIS-Fundación Jiménez Díaz-Universidad Autónoma de Madrid, Madrid, Spain.,Fundación Renal Iñigo Alvarez de Toledo-IRSIN, Madrid, Spain and.,REDINREN, Madrid, Spain
| | - M Concepcion Izquierdo
- Department of Nephrology, IIS-Fundación Jiménez Díaz-Universidad Autónoma de Madrid, Madrid, Spain.,Fundación Renal Iñigo Alvarez de Toledo-IRSIN, Madrid, Spain and.,REDINREN, Madrid, Spain
| | - Lara Valiño-Rivas
- Department of Nephrology, IIS-Fundación Jiménez Díaz-Universidad Autónoma de Madrid, Madrid, Spain.,Fundación Renal Iñigo Alvarez de Toledo-IRSIN, Madrid, Spain and.,REDINREN, Madrid, Spain
| | - Dimitra Nastou
- Department of Nephrology, General Hospital of Syros, Syros, Greece
| | - Ana B Sanz
- Department of Nephrology, IIS-Fundación Jiménez Díaz-Universidad Autónoma de Madrid, Madrid, Spain.,Fundación Renal Iñigo Alvarez de Toledo-IRSIN, Madrid, Spain and.,REDINREN, Madrid, Spain
| | - Alberto Ortiz
- Department of Nephrology, IIS-Fundación Jiménez Díaz-Universidad Autónoma de Madrid, Madrid, Spain.,REDINREN, Madrid, Spain
| | - Maria D Sanchez-Niño
- Department of Nephrology, IIS-Fundación Jiménez Díaz-Universidad Autónoma de Madrid, Madrid, Spain.,Fundación Renal Iñigo Alvarez de Toledo-IRSIN, Madrid, Spain and.,REDINREN, Madrid, Spain
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10
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Hage V, Villain C, Pelletier S, Laville M, Drai J, Fouque D. Bicarbonate Supplement Restores Urinary Klotho Excretion in Chronic Kidney Disease: A Pilot Study. J Ren Nutr 2019; 29:285-288. [DOI: 10.1053/j.jrn.2018.11.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 10/20/2018] [Accepted: 11/06/2018] [Indexed: 11/11/2022] Open
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11
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Liao YL, Chou CC, Lee YJ. The association of indoxyl sulfate with fibroblast growth factor-23 in cats with chronic kidney disease. J Vet Intern Med 2019; 33:686-693. [PMID: 30779214 PMCID: PMC6430881 DOI: 10.1111/jvim.15457] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 02/04/2019] [Indexed: 12/01/2022] Open
Abstract
Background Indoxyl sulfate (IS) has been reported not only to increase with the severity of impaired renal function, but also possibly to be a factor associated with bone abnormalities linked to fibroblast growth factor‐23 (FGF‐23) in humans with chronic kidney disease (CKD). It is not yet known whether this correlation between IS and FGF‐23 holds true for cats with CKD. Hypothesis Accumulation of IS is related to FGF‐23 secretion in cats with CKD. Animals Twenty clinically healthy cats and 73 cats with CKD cases were evaluated retrospectively. Methods The concentrations of IS and FGF‐23 in plasma were determined by high‐performance liquid chromatography and ELISA, respectively. Progression was defined as an increment of 0.5 mg/dL of serum creatinine concentration within 3 months. Results Plasma IS and FGF‐23 concentrations were significantly increased concurrently with decreasing renal function. Higher concentration of FGF‐23 was significantly associated with higher concentration of IS after adjusting for various confounding factors including creatinine and phosphate. Furthermore, the correlation between IS and phosphate was higher than that between FGF‐23 and phosphate. When the renal progression group was compared with the non‐progression group, both IS and FGF‐23 were found to be significantly increased (P < .05). In addition, the area under receiver operator curve of the combination of IS and FGF‐23 predicted renal progression at a level >0.9. Conclusions and Clinical Importance Both FGF‐23 and IS are associated with phosphate metabolism and CKD progression.
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Affiliation(s)
- Yu-Lun Liao
- Department of Veterinary Medicine, College of Veterinary Medicine, National Chung-Hsing University, Taichung, Taiwan
| | - Chi-Chung Chou
- Department of Veterinary Medicine, College of Veterinary Medicine, National Chung-Hsing University, Taichung, Taiwan.,Department and Graduate Institute of Pharmacology, National Defense Medical Center, Taipei, Taiwan
| | - Ya-Jane Lee
- Institute of Veterinary Clinical Science, School of Veterinary Medicine, College of Bio-Resources and Agriculture, National Taiwan University, Taipei, Taiwan.,National Taiwan University Veterinary Hospital, College of Bio-Resources and Agriculture, National Taiwan University, Taipei, Taiwan
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Correlation between Soluble α-Klotho and Renal Function in Patients with Chronic Kidney Disease: A Review and Meta-Analysis. BIOMED RESEARCH INTERNATIONAL 2018; 2018:9481475. [PMID: 30159331 PMCID: PMC6109492 DOI: 10.1155/2018/9481475] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 05/29/2018] [Accepted: 07/11/2018] [Indexed: 01/11/2023]
Abstract
Objective Over decades, numerous inconsistent studies are reported on the relationship between soluble α-Klotho and renal function in patients with chronic kidney disease (CKD). This study aims to perform a meta-analysis to figure out the correlations between soluble α-Klotho and renal function in patients with CKD. Materials and Methods We searched medical and scientific literature databases, PubMed and EMBASE (from the inception to October 2017), for publications that reported studies on associations between soluble α-Klotho and renal function in patients with CKD. Only publications in English were extracted. Summary correlation coefficient (r) values were extracted from each study, and 95% confidence intervals (CIs) were calculated. Publication bias was tested, and sensitivity and subgroup analyses were performed to investigate potential heterogeneity. Results Of 611 studies, 9 publications with 1457 patients were included into the analysis. The following data were extracted from the literature: first author, year of publication, research region, research index, sample size, average age and Pearson or Spearman correlation coefficient, study design, the αKlotho/FGF23 assays utilized, full length, or the C-terminal fragment of FGF23. The pooled r between α-Klotho and estimated glomerular filtration rate (eGFR), FGF-23 were 0.35 (95%CI, 0.23~0.46, and P<0.05), -0.10 (95%CI, -0.19~-0.01, and P<0.05) with remarkable significance, indicating moderate heterogeneity. There was no significant heterogeneity between subgroups in analyses of α-Klotho and eGFR stratified by research region, mean age, and eGFR, but heterogeneity exists in analyses of α-Klotho and FGF-23 stratified by research region. There was no significant correlation between a-klotho and Ca and PTH and PHOS. There was no evidence of publication bias with Egger's test (p=0.360) or with Begg's test (p=0.902) and the distribution of funnel plots was symmetrical in all of our analysis. Conclusions There exists a significant positive correlation between soluble α-Klotho and eGFR in patients with CKD. Also, a significant negative correlation between α-Klotho and FGF23 levels is proven. This raises hope to employ αKlotho and FGF23 as early biomarkers of CKD. However, further large prospective follow-up researches are needed to validate this hypothesis and to explore whether maintaining or elevating the Klotho level could improve renal function and complications in CKD patients.
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Marçais C, Maucort-Boulch D, Drai J, Dantony E, Carlier MC, Blond E, Genet L, Kuentz F, Lataillade D, Legrand E, Moreau-Gaudry X, Jean G, Fouque D. Circulating Klotho Associates With Cardiovascular Morbidity and Mortality During Hemodialysis. J Clin Endocrinol Metab 2017; 102:3154-3161. [PMID: 28402487 DOI: 10.1210/jc.2017-00104] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 04/06/2017] [Indexed: 12/30/2022]
Abstract
BACKGROUND Klotho gene was identified as an aging suppressor. In animals, klotho overexpression extends life span, and defective klotho results in rapid aging and early death. The kidney is the main contributor to circulating klotho levels, and, during chronic kidney disease, renal klotho gene expression is drastically reduced in animals and humans as well. OBJECTIVE We aimed to determine the consequences of a serum klotho (seKL) defect on cardiovascular morbidity and mortality during chronic dialysis. DESIGN The ARNOGENE study was designed to prospectively follow a cohort of hemodialysis patients for 2 years without specific intervention. A total of 769 patients was recruited and followed from the end of 2008 until January 2011. A total of 238 patients was analyzed due to a technical sample conservation issue with other samples. RESULTS The median seKL was markedly reduced, 360.4 ng/L (interquartile range 176.5) as compared with nondialysis chronic kidney disease patients or healthy volunteers. Patients with a seKL above the first quartile (≥280 ng/L) had a significantly reduced occurrence of outcome combining cardiovascular events and cardiovascular death [odds ratio (OR) = 0.39; 0.19 to 0.78, P = 0.008] compared with patient with klotho <280 ng/L. This effect persisted (OR = 0.86; 0.76 to 0.99, P = 0.03) after adjustment on age, sex, diabetes, cardiac insufficiency, dialysis vintage, and serum hemoglobin, albumin, fibroblast growth factor-23, phosphate, and calcium. CONCLUSIONS These results suggest that, during chronic hemodialysis, conservation of seKL >280 ng/L is associated with a better 2-year cardiovascular protection. Thus, a preserved klotho function supports cardiovascular protection and may represent a prognostic tool and therapeutic target for cardiovascular disease.
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Affiliation(s)
- Christophe Marçais
- University Lyon, UCBL, Service de Biochimie et Biologie Moléculaire, Centre Hospitalier Lyon Sud, CarMeN, CENS, F-69495 Pierre Bénite, France
| | - Delphine Maucort-Boulch
- University Lyon, UCBL, CNRS Laboratoire de Biométrie et Biologie Evolutive, Service de Biostatistique, Hospices Civils de Lyon, F-69495 Pierre Bénite, France
| | - Jocelyne Drai
- University Lyon, UCBL, Service de Biochimie et Biologie Moléculaire, Centre Hospitalier Lyon Sud, CarMeN, CENS, F-69495 Pierre Bénite, France
| | - Emmanuelle Dantony
- University Lyon, UCBL, CNRS Laboratoire de Biométrie et Biologie Evolutive, Service de Biostatistique, Hospices Civils de Lyon, F-69495 Pierre Bénite, France
| | - Marie-Christine Carlier
- University Lyon, UCBL, Service de Biochimie et Biologie Moléculaire, Centre Hospitalier Lyon Sud, CarMeN, CENS, F-69495 Pierre Bénite, France
| | - Emilie Blond
- University Lyon, UCBL, Service de Biochimie et Biologie Moléculaire, Centre Hospitalier Lyon Sud, CarMeN, CENS, F-69495 Pierre Bénite, France
| | - Leslie Genet
- Service de Néphrologie Nutrition Dialyse, Centre Hospitalier Lyon Sud, F-69495 Pierre-Bénite, France
| | - François Kuentz
- Centre de Dialyse des Eaux Claires, AGDUC, F-38000 Grenoble, France
| | | | - Eric Legrand
- Service de Néphrologie Hémodialyse, Centre Hospitalier Ardèche Nord, F-07010 Annonay, France
| | | | | | - Denis Fouque
- University Lyon, UCBL, CarMeN, CENS, Service de Néphrologie-Nutrition-Dialyse, Centre Hospitalier Lyon Sud, F-69495 Pierre Bénite, France
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Tan SJ, Smith ER, Holt SG, Hewitson TD, Toussaint ND. Soluble klotho may be a marker of phosphate reabsorption. Clin Kidney J 2017; 10:397-404. [PMID: 28616218 PMCID: PMC5466110 DOI: 10.1093/ckj/sfw146] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 12/05/2016] [Indexed: 12/20/2022] Open
Abstract
Background: Membrane-bound α-klotho functions as a co-receptor with fibroblast growth factor receptor at the renal tubule conferring specificity to fibroblast growth factor-23 (FGF-23), allowing it to inhibit tubular phosphate reabsorption at physiological concentrations. α-klotho also exists as a soluble protein. However, the complex interrelationships between soluble α-klotho (sKl), FGF-23 and phosphate reabsorption are poorly understood, with little known about the links between sKl, FGF-23 and phosphate reabsorption in chronic kidney disease (CKD). This study addresses this issue in a cohort of patients with and without CKD. Methods: We conducted a single-centre, cross-sectional study of contemporaneously obtained samples of blood and 24-h urine biochemistry along with sKl and intact FGF-23 (iFGF-23) from non-dialysis-dependent CKD patients and healthy volunteers. Pearson's correlation coefficients were used to determine correlations between natural log-transformed (Ln) sKl and iFGF-23 with other parameters of interest. Backward multivariate analysis was undertaken to evaluate the relationship between mineral parameters. Results: One hundred and sixteen participants (77 with CKD and 39 healthy volunteers) were studied, of which 74 (63.8%) were male. The median age was 61 (interquartile range 49-71) years. Those with CKD had lower sKl (408 versus 542 pg/mL), higher iFGF-23 (94 versus 41 pg/mL), higher fractional excretion of phosphate (25.05 versus 10.98%) and lower daily urinary phosphate excretion (UPE) (24.8 versus 32.3 mmol/L) compared with healthy volunteers (all P ≤ 0.002). Age correlated inversely and estimated glomerular filtration rate (eGFR) correlated positively with phosphate reabsorption and Ln(sKl), while the opposite was seen with Ln(iFGF23). Upon multivariate analysis, eGFR, Ln(sKl) and parathyroid hormone were independently associated with phosphate reabsorption, whereas Ln(iFGF-23) was not, after adjustment for age. Conclusions: Abnormalities in phosphate regulatory pathways are disturbed early in CKD. While iFGF-23 is associated with phosphate excretion on univariate analyses, sKl demonstrates a significant association with phosphate reabsorption independent of iFGF-23, and this relationship deserves further exploration.
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Affiliation(s)
- Sven-Jean Tan
- Department of Nephrology, Royal Melbourne Hospital, Parkville, Australia
- Department of Medicine (RMH), University of Melbourne, Melbourne, Australia
| | - Edward R. Smith
- Department of Nephrology, Royal Melbourne Hospital, Parkville, Australia
| | - Stephen G. Holt
- Department of Nephrology, Royal Melbourne Hospital, Parkville, Australia
- Department of Medicine (RMH), University of Melbourne, Melbourne, Australia
| | - Tim D. Hewitson
- Department of Nephrology, Royal Melbourne Hospital, Parkville, Australia
- Department of Medicine (RMH), University of Melbourne, Melbourne, Australia
| | - Nigel D. Toussaint
- Department of Nephrology, Royal Melbourne Hospital, Parkville, Australia
- Department of Medicine (RMH), University of Melbourne, Melbourne, Australia
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15
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Phosphate and FGF23 in the renoprotective benefit of RAAS inhibition. Pharmacol Res 2016; 106:87-91. [DOI: 10.1016/j.phrs.2016.02.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 02/07/2016] [Accepted: 02/15/2016] [Indexed: 01/15/2023]
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Shroff R, Aitkenhead H, Costa N, Trivelli A, Litwin M, Picca S, Anarat A, Sallay P, Ozaltin F, Zurowska A, Jankauskiene A, Montini G, Charbit M, Schaefer F, Wühl E. Normal 25-Hydroxyvitamin D Levels Are Associated with Less Proteinuria and Attenuate Renal Failure Progression in Children with CKD. J Am Soc Nephrol 2015; 27:314-22. [PMID: 26069294 DOI: 10.1681/asn.2014090947] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 03/30/2015] [Indexed: 12/21/2022] Open
Abstract
Angiotensin-converting enzyme inhibitors (ACEi) for renin-angiotensin-aldosterone system (RAAS) blockade are routinely used to slow CKD progression. However, vitamin D may also promote renoprotection by suppressing renin transcription through cross-talk between RAAS and vitamin D-fibroblast growth factor-23 (FGF-23)-Klotho pathways. To determine whether vitamin D levels influence proteinuria and CKD progression in children, we performed a post hoc analysis of the Effect of Strict Blood Pressure Control and ACE Inhibition on Progression of CKD in Pediatric Patients (ESCAPE) cohort. In 167 children (median eGFR 51 ml/min per 1.73 m(2)), serum 25-hydroxyvitamin D (25(OH)D), FGF-23, and Klotho levels were measured at baseline and after a median 8 months on ACEi. Children with lower 25(OH)D levels had higher urinary protein/creatinine ratios at baseline (P=0.03) and at follow-up (P=0.006). Levels of 25(OH)D and serum vitamin D-binding protein were not associated, but 25(OH)D ≤50 nmol/L associated with higher diastolic BP (P=0.004). ACEi therapy also associated with increased Klotho levels (P<0.001). The annualized loss of eGFR was inversely associated with baseline 25(OH)D level (P<0.001, r=0.32). Five-year renal survival was 75% in patients with baseline 25(OH)D ≥50 nmol/L and 50% in those with lower 25(OH)D levels (P<0.001). This renoprotective effect remained significant but attenuated with ACEi therapy (P=0.05). Renal survival increased 8.2% per 10 nmol/L increase in 25(OH)D (P=0.03), independent of eGFR; proteinuria, BP, and FGF-23 levels; and underlying renal diagnosis. In children with CKD, 25(OH)D ≥50 nmol/L was associated with greater preservation of renal function. This effect was present but attenuated with concomitant ACEi therapy.
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Affiliation(s)
- Rukshana Shroff
- Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom;
| | - Helen Aitkenhead
- Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom
| | - Nikola Costa
- Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom
| | | | | | | | - Ali Anarat
- Cukurova University School of Medicine, Balcali, Adana, Turkey
| | - Peter Sallay
- Semmelweis University Budapest, 1st Department of Pediatrics, Budapest, Hungary
| | - Fatih Ozaltin
- Department of Pediatric Nephrology, Hacettepe University Faculty of Medicine, Sihhiye, Ankara, Turkey
| | - Aleksandra Zurowska
- Department of Paediatric and Adolescent Nephrology and Hypertension, Medical University of Gdansk, Gdansk, Poland
| | | | | | | | - Franz Schaefer
- Center for Pediatric & Adolescent Medicine, University of Heidelberg, Germany
| | - Elke Wühl
- Center for Pediatric & Adolescent Medicine, University of Heidelberg, Germany
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