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Jørgensen HS, de Loor H, Billen J, Peersman N, Vermeersch P, Heijboer AC, Ivison F, Vanderschueren D, Bouillon R, Naesens M, Kuypers D, Evenepoel P. Vitamin D Metabolites Before and After Kidney Transplantation in Patients Who Are Anephric. Am J Kidney Dis 2024:S0272-6386(24)00782-0. [PMID: 38796137 DOI: 10.1053/j.ajkd.2024.03.025] [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: 01/08/2024] [Revised: 03/14/2024] [Accepted: 03/26/2024] [Indexed: 05/28/2024]
Abstract
RATIONALE & OBJECTIVE Kidneys are vital for vitamin D metabolism, and disruptions in both production and catabolism occur in chronic kidney disease. Although vitamin D activation occurs in numerous tissues, the kidneys are the most relevant source of circulating active vitamin D. This study investigates extrarenal vitamin D activation and the impact of kidney transplantation on vitamin D metabolism in patients who are anephric. STUDY DESIGN Case series. SETTING & PARTICIPANTS Adult patients with previous bilateral nephrectomy (anephric) not receiving active vitamin D therapy evaluated at the time of (N=38) and 1 year after (n=25) kidney transplantation. ANALYTICAL APPROACH Chromatography with tandem mass spectrometry was used to measure vitamin D metabolites. Activity of CYP24A1 [24,25(OH)2D/25(OH)D] and CYP27B1 [1α,25(OH)2D/25(OH)D] is expressed as metabolic ratios. Differences between time points were evaluated by paired t-test or Wilcoxon matched-pairs signed-rank test. RESULTS At time of transplantation, 1α,25(OH)2D was detectable in all patients (4-36pg/mL). There was a linear relationship between 25(OH)D and 1α,25(OH)2D levels (r=0.58, P<0.001), with 25(OH)D explaining 34% of the variation in 1α,25(OH)2D levels. There were no associations between 1α,25(OH)2D and biointact parathyroid hormone (PTH) or fibroblast growth factor 23 (FGF-23). One year after transplantation, 1α,25(OH)2D levels recovered (+205%), and CYP27B1 activity increased (+352%). Measures of vitamin D catabolism, 24,25(OH)2D and CYP24A1 activity increased 3- to 5-fold. Also, at 12 months after transplantation, 1α,25(OH)2D was positively correlated with PTH (ρ=0.603, P=0.04) but not with levels of 25(OH)D or FGF-23. LIMITATIONS Retrospective, observational study design with a small cohort size. CONCLUSIONS Low-normal levels of 1α,25(OH)2D was demonstrated in anephric patients, indicating production outside the kidneys. This extrarenal CYP27B1 activity may be more substrate driven than hormonally regulated. Kidney transplantation seems to restore kidney CYP27B1 and CYP24A1 activity, as evaluated by vitamin D metabolic ratios, resulting in both increased vitamin D production and catabolism. These findings may have implications for vitamin D supplementation strategies in the setting of kidney failure and transplantation. PLAIN-LANGUAGE SUMMARY Vitamin D activation occurs in multiple tissues, but the kidneys are considered the only relevant source of circulating levels. This study investigates vitamin D activation outside the kidneys by measuring vitamin D metabolites in 38 patients without kidneys. Active vitamin D was detectable in all patients, indicating production outside of the kidneys. There was a strong relationship between active and precursor vitamin D levels, but no association with mineral metabolism hormones, indicating that vitamin D production was more substrate dependent than hormonally regulated. One year after kidney transplantation, active vitamin D levels increased 2-fold and breakdown products increased 3-fold, indicating that production and degradation of the hormone recovers after kidney transplantation. These findings are relevant for future research into vitamin D supplementation in kidney failure.
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Affiliation(s)
- Hanne Skou Jørgensen
- Institute of Clinical Medicine, Aarhus University, Aarhus, and Department of Nephrology, Aalborg University Hospital, Aalborg, Denmark
| | - Henriette de Loor
- Department of Immunology and Transplantation, Nephrology and Renal Transplantation Research Group, Leuven University Hospitals, Leuven, Belgium
| | - Jaak Billen
- Clinical Department of Laboratory Medicine, Leuven University Hospitals, Leuven, Belgium
| | - Nele Peersman
- Department of Cardiovascular Sciences, Leuven University Hospitals, Leuven, Belgium; Clinical Department of Laboratory Medicine, Leuven University Hospitals, Leuven, Belgium
| | - Pieter Vermeersch
- Department of Cardiovascular Sciences, Leuven University Hospitals, Leuven, Belgium; Clinical Department of Laboratory Medicine, Leuven University Hospitals, Leuven, Belgium
| | - Annemieke C Heijboer
- Department of Clinical Chemistry, Endocrine Laboratory, Amsterdam Gastroenterology Endocrinology and Metabolism, Amsterdam UMC, Vrije Universiteit Amsterdam and University of Amsterdam, Amsterdam, the Netherlands
| | - Fiona Ivison
- Department of Clinical Biochemistry, Manchester University NHS Foundation Trust, Manchester, United Kingdom
| | - Dirk Vanderschueren
- Laboratory of Clinical and Experimental Endocrinology, Leuven University Hospitals, Leuven, Belgium; KU Leuven, and Clinical Department of Endocrinology, Leuven University Hospitals, Leuven, Belgium
| | - Roger Bouillon
- Department of Cardiovascular Sciences, Leuven University Hospitals, Leuven, Belgium
| | - Maarten Naesens
- Department of Immunology and Transplantation, Nephrology and Renal Transplantation Research Group, Leuven University Hospitals, Leuven, Belgium; Department of Medicine, Division of Nephrology, Leuven University Hospitals, Leuven, Belgium
| | - Dirk Kuypers
- Department of Immunology and Transplantation, Nephrology and Renal Transplantation Research Group, Leuven University Hospitals, Leuven, Belgium; Department of Medicine, Division of Nephrology, Leuven University Hospitals, Leuven, Belgium
| | - Pieter Evenepoel
- Department of Immunology and Transplantation, Nephrology and Renal Transplantation Research Group, Leuven University Hospitals, Leuven, Belgium; Department of Medicine, Division of Nephrology, Leuven University Hospitals, Leuven, Belgium.
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Ryu JH, Jeon HJ, Han R, Jung HY, Kim MG, Huh KH, Park JB, Kang KP, Han S, Yang J. High pretransplant FGF23 level is associated with persistent vitamin D insufficiency and poor graft survival in kidney transplant patients. Sci Rep 2023; 13:19640. [PMID: 37949967 PMCID: PMC10638428 DOI: 10.1038/s41598-023-46889-0] [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: 08/08/2023] [Accepted: 11/06/2023] [Indexed: 11/12/2023] Open
Abstract
Vitamin D3 (25[OH]D3) insufficiency and fibroblast growth factor 23 (FGF23) elevation are usually attenuated after kidney transplantation (KT). However, elevated FGF23 may be associated with poor graft outcomes and vitamin D insufficiency after KT. This study investigated the effect of pretransplant FGF23 levels on post-KT 25(OH)D3 status and graft outcomes. Serum FGF23 levels from 400 participants of the KoreaN Cohort Study for Outcome in Patients With Kidney Transplantation were measured. Annual serum 25(OH)D3 levels, all-cause mortality, cardiovascular event, and graft survival were assessed according to baseline FGF23 levels. Serum 25(OH)D3 levels were initially increased 1 year after KT (12.6 ± 7.4 vs. 22.6 ± 6.4 ng/mL). However, the prevalence of post-KT vitamin D deficiency increased again after post-KT 3 years (79.1% at baseline, 30.8% and 37.8% at 3 and 6 years, respectively). Serum FGF23 level was decreased 3 years post-KT. When participants were categorized into tertiles according to baseline FGF23 level (low, middle, high), 25(OH)D3 level in the low FGF23 group was persistently low at a median follow-up of 8.3 years. Furthermore, high baseline FGF23 level was a risk factor for poor graft survival (HR 5.882, 95% C.I.; 1.443-23.976, P = 0.013). Elevated FGF23 levels are associated with persistently low post-transplant vitamin D levels and poor graft survival.
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Affiliation(s)
- Jung-Hwa Ryu
- Department of Internal Medicine, Ewha Womans University Seoul Hospital, Seoul, Republic of Korea
| | - Hee Jung Jeon
- Department of Internal Medicine, Hallym University College of Medicine, Seoul, Republic of Korea
| | - Ro Han
- Department of Internal Medicine, Gachon University Gil Medical Center, Incheon, Republic of Korea
| | - Hee-Yeon Jung
- Department of Internal Medicine, Kyungpook National University Hospital, Daegu, Republic of Korea
| | - Myung-Gyu Kim
- Department of Internal Medicine, Korea University College of Medicine, Seoul, Republic of Korea
| | - Kyu Ha Huh
- Department of Surgery, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Jae Berm Park
- Department of Surgery, Seoul Samsung Medical Center, Sungkyunkwan University, Seoul, Republic of Korea
| | - Kyung Pyo Kang
- Department of Internal Medicine, Jeonbuk National University Hospital, Jeonju, Republic of Korea
| | - Seungyeup Han
- Department of Internal Medicine, Dongsan Medical Center, Keimyung University, Daegu, Republic of Korea
| | - Jaeseok Yang
- Department of Internal Medicine, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea.
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Kubota M, Hamasaki Y, Hashimoto J, Aoki Y, Kawamura T, Saito A, Yuasa R, Muramatsu M, Komaba H, Toyoda M, Fukagawa M, Shishido S, Sakai K. Fibroblast growth factor 23-Klotho and mineral metabolism in the first year after pediatric kidney transplantation: A single-center prospective study. Pediatr Transplant 2023; 27:e14440. [PMID: 36471536 DOI: 10.1111/petr.14440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 10/27/2022] [Accepted: 10/28/2022] [Indexed: 12/12/2022]
Abstract
BACKGROUND The role of fibroblast growth factor 23 (FGF23) levels in mineral metabolism before and after kidney transplantation in pediatric patients is poorly understood. METHODS We prospectively evaluated 24 patients under 18 years of age (4.5 [3.3-9.8] years) who underwent living kidney transplantation between July 2016 and March 2018, and measured intact FGF23 and serum αKlotho levels, and other parameters of mineral metabolism before and after transplantation (Day 7, 1 and 4 months, and 1 year). Relationships between parameters were examined by linear analysis. RESULTS FGF23 level was 440.8 [63.4-5916.3] pg/ml pre-transplant and decreased significantly to 37.1 [16.0-71.5] pg/ml at Day 7 post-transplant (-91.6%, p < .001). Thereafter, it remained at normal levels until 1 year. αKlotho level was 785 [568-1292] pg/ml pre-transplant and remained low at Day 7 and 1 month post-transplant, with an increasing trend at 4 months. Post-transplant phosphorus levels were significantly decreased compared with pre-transplant, with a lowest level of 1.7 [1.3-2.9] mg/dl, -5.7 [-6.8, -3.8] SD at Day 4, followed by gradual recovery. Phosphorus levels and the ratio of tubular maximum phosphate reabsorption were significantly and negatively associated with pre-transplant FGF23 until 4 months of post-transplant. Pre-transplant αKlotho was negatively associated with pre-transplant FGF23 but not FGF23 or other parameters after transplantation. CONCLUSION FGF23 in pediatric kidney transplant patients decreased rapidly after transplantation and associated with post-transplant hypophosphatemia and increased phosphorus excretion. Post-transplant αKlotho was low early post-transplant but tended to increase subsequently. Post-transplant αKlotho was unaffected by pre-transplant FGF23 or other factors, suggesting pre-transplant chronic kidney disease status has no effect.
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Affiliation(s)
- Mai Kubota
- Department of Nephrology, Toho University, Faculty of Medicine, Tokyo, Japan
| | - Yuko Hamasaki
- Department of Nephrology, Toho University, Faculty of Medicine, Tokyo, Japan
| | - Junya Hashimoto
- Department of Nephrology, Toho University, Faculty of Medicine, Tokyo, Japan
| | - Yujiro Aoki
- Department of Nephrology, Toho University, Faculty of Medicine, Tokyo, Japan
| | - Takeshi Kawamura
- Department of Nephrology, Toho University, Faculty of Medicine, Tokyo, Japan
| | - Akinobu Saito
- Department of Nephrology, Toho University, Faculty of Medicine, Tokyo, Japan
| | - Rena Yuasa
- Department of Nephrology, Toho University, Faculty of Medicine, Tokyo, Japan
| | - Masaki Muramatsu
- Department of Nephrology, Toho University, Faculty of Medicine, Tokyo, Japan
| | - Hirotaka Komaba
- Division of Nephrology, Endocrinology and Metabolism, Tokai University School of Medicine, Isehara, Japan
| | - Masao Toyoda
- Division of Nephrology, Endocrinology and Metabolism, Tokai University School of Medicine, Isehara, Japan
| | - Masafumi Fukagawa
- Division of Nephrology, Endocrinology and Metabolism, Tokai University School of Medicine, Isehara, Japan
| | - Seichiro Shishido
- Department of Pediatric Nephrology, Toho University, Faculty of Medicine, Tokyo, Japan
| | - Ken Sakai
- Department of Nephrology, Toho University, Faculty of Medicine, Tokyo, Japan
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Prytula A, Shroff R, Krupka K, Deschepper E, Bacchetta J, Ariceta G, Awan A, Benetti E, Büscher A, Berta L, Carraro A, Christian M, Dello Strologo L, Doerry K, Haumann S, Klaus G, Kempf C, Kranz B, Oh J, Pape L, Pohl M, Printza N, Rubik J, Schmitt CP, Shenoy M, Spartà G, Staude H, Sweeney C, Weber L, Weber S, Weitz M, Haffner D, Tönshoff B. Hyperparathyroidism Is an Independent Risk Factor for Allograft Dysfunction in Pediatric Kidney Transplantation. Kidney Int Rep 2022; 8:81-90. [PMID: 36644359 PMCID: PMC9832060 DOI: 10.1016/j.ekir.2022.10.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 09/15/2022] [Accepted: 10/17/2022] [Indexed: 11/06/2022] Open
Abstract
Introduction Little is known about the consequences of deranged chronic kidney disease-mineral and bone disorder (CKD-MBD) parameters on kidney allograft function in children. We examined a relationship between these parameters over time and allograft outcome. Methods This registry study from the Cooperative European Paediatric Renal Transplant Initiative (CERTAIN) collected data at baseline, months 1, 3, 6, 9, and 12 after transplant; and every 6 months thereafter up to 5 years. Survival analysis for a composite end point of graft loss or estimated glomerular filtration rate (eGFR) ≤30 ml/min per 1.73 m2 or a ≥50% decline from eGFR at month 1 posttransplant was performed. Associations of parathyroid hormone (PTH), calcium, phosphate, and 25-hydroxyvitamin D (25(OH)D) with allograft outcome were investigated using conventional stratified Cox proportional hazards models and further verified with marginal structural models with time-varying covariates. Results We report on 1210 patients (61% boys) from 16 European countries. The composite end point was reached in 250 grafts (21%), of which 11 (4%) were allograft losses. In the conventional Cox proportional hazards models adjusted for potential confounders, only hyperparathyroidism (hazard ratio [HR], 2.94; 95% confidence interval [CI], 1.82-4.74) and hyperphosphatemia (HR, 1.94; 95% CI, 1.28-2.92) were associated with the composite end point. Marginal structural models showed similar results for hyperparathyroidism (HR, 2.74; 95% CI, 1.71-4.38), whereas hyperphosphatemia was no longer significant (HR, 1.35; 95% CI, 0.87-2.09), suggesting that its association with graft dysfunction can be ascribed to a decline in eGFR. Conclusion Hyperparathyroidism is a potential independent risk factor for allograft dysfunction in children.
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Affiliation(s)
- Agnieszka Prytula
- Department of Pediatric Nephrology and Rheumatology, Ghent University Hospital, Ghent, Belgium
- Correspondence: Agnieszka Prytula, Department of Pediatric Nephrology and Rheumatology, Ghent University Hospital, Corneel Heymanslaan 10, Ghent 9000, Belgium.
| | - Rukshana Shroff
- Renal Unit, University College London Great Ormond Street Hospital, London, United Kingdom
| | - Kai Krupka
- Department of Pediatrics I, University Children’s Hospital Heidelberg, Heidelberg, Germany
| | - Ellen Deschepper
- Biostatistics Unit, Department of Public Health and Primary Care, Ghent University, Ghent, Belgium
| | - Justine Bacchetta
- Reference Center for Rare Renal Diseases, Reference Center for Rare Diseases of Calcium and Phosphate Metabolism, Hospices Civils de Lyon, France
| | - Gema Ariceta
- Pediatric Nephrology. University Hospital Vall d’ Hebron, Barcelona, Spain
| | - Atif Awan
- Department of Nephrology and Transplantation, Temple Street, Dublin, Ireland
| | - Elisa Benetti
- Pediatric Nephrology, Dialysis and Transplant Unit, Laboratory of Immunopathology and Molecular Biology of the Kidney, Department of Women’s and Children’s Health, Padua University Hospital, Padua, Italy
| | - Anja Büscher
- Department of Pediatrics II, University Hospital of Essen, Essen, Germany
| | - László Berta
- First Department of Pediatrics, Semmelweis University, Budapest, Hungary
| | - Andrea Carraro
- Pediatric Nephrology, Dialysis and Transplant Unit, Laboratory of Immunopathology and Molecular Biology of the Kidney, Department of Women’s and Children’s Health, Padua University Hospital, Padua, Italy
| | | | - Luca Dello Strologo
- Renal Transplant Unit, Bambino Gesù Children’s Research Hospital Istituto di Ricovero e Cura a Carattere Scientifico, Rome, Italy
| | - Katja Doerry
- Department of Pediatric Nephrology and Transplantation, University Children’s Hospital, University Medical Center Hamburg/Eppendorf, Hamburg, Germany
| | - Sophie Haumann
- Pediatric Nephrology, Children’s and Adolescents’ Hospital, University Hospital of Cologne, Faculty of Medicine, University of Cologne, Cologne, Germany
| | - Guenter Klaus
- KfH-Pediatric Kidney Center and Department of Pediatrics, Philipps-University of Marburg, Marburg, Germany
| | - Caroline Kempf
- Department of Pediatric Gastroenterology, Nephrology and Metabolism, Charité–University Medicine Berlin, Berlin, Germany
| | | | - Jun Oh
- Department of Pediatric Nephrology and Transplantation, University Children’s Hospital, University Medical Center Hamburg/Eppendorf, Hamburg, Germany
| | - Lars Pape
- Department of Pediatrics II, University Hospital of Essen, Essen, Germany
| | - Martin Pohl
- Department of General Pediatrics, Adolescent Medicine and Neonatology, Medical Center–University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Nikoleta Printza
- Pediatric Nephrology Unit, Pediatric Department I, Hippokration General Hospital, Aristotle University, Thessaloniki, Greece
| | - Jacek Rubik
- Department of Nephrology, Kidney Transplantation and Arterial Hypertension, Children’s Memorial Health Institute, Warsaw, Poland
| | - Claus Peter Schmitt
- Department of Pediatrics I, University Children’s Hospital Heidelberg, Heidelberg, Germany
| | - Mohan Shenoy
- Royal Manchester Children’s Hospital, Manchester, United Kingdom
| | - Giuseppina Spartà
- Department of Pediatric Nephrology, University Children’s Hospital Zurich, Zurich, Switzerland
| | | | - Clodagh Sweeney
- Department of Nephrology and Transplantation, Temple Street, Dublin, Ireland
| | - Lutz Weber
- Pediatric Nephrology, Children’s and Adolescents’ Hospital, University Hospital of Cologne, Faculty of Medicine, University of Cologne, Cologne, Germany
| | - Stefanie Weber
- KfH-Pediatric Kidney Center and Department of Pediatrics, Philipps-University of Marburg, Marburg, Germany
| | - Marcus Weitz
- Department of General Pediatrics and Hematology/Oncology, University Children’s Hospital Tuebingen, Tuebingen, Germany
| | - Dieter Haffner
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Hannover, Germany
| | - Burkhard Tönshoff
- Department of Pediatrics I, University Children’s Hospital Heidelberg, Heidelberg, Germany
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Gupta M, Orozco G, Rao M, Gedaly R, Malluche HH, Neyra JA. The Role of Alterations in Alpha-Klotho and FGF-23 in Kidney Transplantation and Kidney Donation. Front Med (Lausanne) 2022; 9:803016. [PMID: 35602513 PMCID: PMC9121872 DOI: 10.3389/fmed.2022.803016] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 02/03/2022] [Indexed: 12/12/2022] Open
Abstract
Cardiovascular disease and mineral bone disorders are major contributors to morbidity and mortality among patients with chronic kidney disease and often persist after renal transplantation. Ongoing hormonal imbalances after kidney transplant (KT) are associated with loss of graft function and poor outcomes. Fibroblast growth factor 23 (FGF-23) and its co-receptor, α-Klotho, are key factors in the underlying mechanisms that integrate accelerated atherosclerosis, vascular calcification, mineral disorders, and osteodystrophy. On the other hand, kidney donation is also associated with endocrine and metabolic adaptations that include transient increases in circulating FGF-23 and decreases in α-Klotho levels. However, the long-term impact of these alterations and their clinical relevance have not yet been determined. This manuscript aims to review and summarize current data on the role of FGF-23 and α-Klotho in the endocrine response to KT and living kidney donation, and importantly, underscore specific areas of research that may enhance diagnostics and therapeutics in the growing population of KT recipients and kidney donors.
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Affiliation(s)
- Meera Gupta
- Department of Surgery - Transplant Division, University of Kentucky, College of Medicine, Lexington, KY, United States
- Department of Surgery, University of Kentucky, Lexington, KY, United States
- *Correspondence: Meera Gupta
| | - Gabriel Orozco
- Department of Surgery - Transplant Division, University of Kentucky, College of Medicine, Lexington, KY, United States
- Department of Surgery, University of Kentucky, Lexington, KY, United States
| | - Madhumati Rao
- Department of Internal Medicine - Nephrology, Bone and Mineral Metabolism Division, University of Kentucky, College of Medicine, Lexington, KY, United States
| | - Roberto Gedaly
- Department of Surgery - Transplant Division, University of Kentucky, College of Medicine, Lexington, KY, United States
- Department of Surgery, University of Kentucky, Lexington, KY, United States
| | - Hartmut H. Malluche
- Department of Internal Medicine - Nephrology, Bone and Mineral Metabolism Division, University of Kentucky, College of Medicine, Lexington, KY, United States
| | - Javier A. Neyra
- Department of Internal Medicine - Nephrology, Bone and Mineral Metabolism Division, University of Kentucky, College of Medicine, Lexington, KY, United States
- Division of Nephrology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- Javier A. Neyra
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Vanderstraeten K, De Pauw R, Knops N, Bouts A, Cransberg K, El Amouri A, Raes A, Prytuła A. Body mass index is associated with hyperparathyroidism in pediatric kidney transplant recipients. Pediatr Nephrol 2021; 36:977-986. [PMID: 33034742 DOI: 10.1007/s00467-020-04796-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 09/01/2020] [Accepted: 09/21/2020] [Indexed: 12/19/2022]
Abstract
BACKGROUND Hyperparathyroidism persists in up to 50% of pediatric kidney transplant recipients. The aims of this study were to describe the evolution of parathyroid hormone (PTH) in the first year after transplantation and to identify factors associated with hyperparathyroidism. METHODS This retrospective study included children who underwent kidney transplantation at the University Hospitals of Ghent, Leuven, Rotterdam, or Amsterdam. Data from 149 patients were collected before and up to 12 months after transplantation. Severe hyperparathyroidism was defined as PTH 2-fold above the reference value. Factors associated with hyperparathyroidism and severe hyperparathyroidism were identified using multivariate logistic regression analysis. RESULTS Before transplantation, 97 out of 137 patients (71%) had hyperparathyroidism. The probability of hyperparathyroidism and severe hyperparathyroidism declined from 0.49 and 0.17 to 0.29 and 0.09 at 3 and 12 months after transplantation, respectively. BMI SDS (β: 0.509; p = 0.011; 95% CI: 1.122-2.468), eGFR (β: - 0.227; p = 0.030; 95% CI: 0.649-0.978), and pre-transplant hyperparathyroidism (β: 1.149; p = 0.039; 95% CI: 1.062-9.369) were associated with hyperparathyroidism 12 months after transplantation. Pre-transplant hyperparathyroidism (β: 2.115; p = 0.044; 95% CI: 1.055-65.084), defined as intact parathormone (iPTH) levels > 65 ng/l (6.9 pmol/l) or 1-84 PTH > 58 ng/l (6.2 pmol/l), was associated with severe hyperparathyroidism at 3 months. Only eGFR (β: - 0.488; p = 0.010; 95% CI: 0.425-0.888) was inversely associated with severe hyperparathyroidism at 9 months after transplantation. CONCLUSIONS Allograft function remains the main determinant of severe hyperparathyroidism after transplantation. Our findings emphasize the importance of BMI and pre-transplant PTH control.
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Affiliation(s)
- Karen Vanderstraeten
- Department of Pediatric Nephrology and Rheumatology, Ghent University Hospital, Corneel Heymanslaan 10, 9000, Ghent, Belgium
| | - Rani De Pauw
- Department of Pediatric Nephrology and Rheumatology, Ghent University Hospital, Corneel Heymanslaan 10, 9000, Ghent, Belgium
| | - Noël Knops
- Department of Pediatric Nephrology, University Hospitals Leuven, Leuven, Belgium
| | - Antonia Bouts
- Department of Pediatric Nephrology, Emma Children's Hospital, Amsterdam University Medical Center, Amsterdam, Netherlands
| | - Karlien Cransberg
- Department of Pediatric Nephrology, Erasmus Medical Center - Sophia Children's Hospital, Rotterdam, Netherlands
| | - Amina El Amouri
- Department of Pediatric Nephrology and Rheumatology, Ghent University Hospital, Corneel Heymanslaan 10, 9000, Ghent, Belgium
| | - Ann Raes
- Department of Pediatric Nephrology and Rheumatology, Ghent University Hospital, Corneel Heymanslaan 10, 9000, Ghent, Belgium
| | - Agnieszka Prytuła
- Department of Pediatric Nephrology and Rheumatology, Ghent University Hospital, Corneel Heymanslaan 10, 9000, Ghent, Belgium.
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Uremic Toxins, Oxidative Stress, Atherosclerosis in Chronic Kidney Disease, and Kidney Transplantation. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2021; 2021:6651367. [PMID: 33628373 PMCID: PMC7895596 DOI: 10.1155/2021/6651367] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 01/25/2021] [Accepted: 01/29/2021] [Indexed: 12/21/2022]
Abstract
Patients with chronic kidney disease (CKD) are at a high risk for cardiovascular disease (CVD), and approximately half of all deaths among patients with CKD are a direct result of CVD. The premature cardiovascular disease extends from mild to moderate CKD stages, and the severity of CVD and the risk of death increase with a decline in kidney function. Successful kidney transplantation significantly decreases the risk of death relative to long-term dialysis treatment; nevertheless, the prevalence of CVD remains high and is responsible for approximately 20-35% of mortality in renal transplant recipients. The prevalence of traditional and nontraditional risk factors for CVD is higher in patients with CKD and transplant recipients compared with the general population; however, it can only partly explain the highly increased cardiovascular burden in CKD patients. Nontraditional risk factors, unique to CKD patients, include proteinuria, disturbed calcium, and phosphate metabolism, anemia, fluid overload, and accumulation of uremic toxins. This accumulation of uremic toxins is associated with systemic alterations including inflammation and oxidative stress which are considered crucial in CKD progression and CKD-related CVD. Kidney transplantation can mitigate the impact of some of these nontraditional factors, but they typically persist to some degree following transplantation. Taking into consideration the scarcity of data on uremic waste products, oxidative stress, and their relation to atherosclerosis in renal transplantation, in the review, we discussed the impact of uremic toxins on vascular dysfunction in CKD patients and kidney transplant recipients. Special attention was paid to the role of native and transplanted kidney function.
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Haffner D, Leifheit-Nestler M. CKD-MBD post kidney transplantation. Pediatr Nephrol 2021; 36:41-50. [PMID: 31858226 DOI: 10.1007/s00467-019-04421-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 10/28/2019] [Accepted: 11/12/2019] [Indexed: 12/22/2022]
Abstract
Complications of chronic kidney disease-associated mineral and bone disorders (CKD-MBD) are frequently observed in pediatric kidney transplant recipients and are associated with high morbidity, including growth failure, leg deformities, bone pain, fractures, osteonecrosis, and vascular calcification. Post-transplant CKD-MBD is mainly due to preexisting renal osteodystrophy and cardiovascular changes at the time of transplantation, glucocorticoid treatment, and reduced graft function. In addition, persistent elevated levels of parathyroid hormone (PTH) and fibroblast growth factor 23 may cause hypophosphatemia, resulting in impaired bone mineralization. Patient monitoring should include assessment of growth, leg deformities, and serum levels of calcium, phosphate, magnesium, alkaline phosphatase, 25-hydroxyvitamin D, and PTH. Therapy should primarily focus on regular physical activity, preservation of transplant function, and steroid-sparing immunosuppressive protocols. In addition, adequate monitoring and treatment of vitamin D and mineral metabolism including vitamin D supplementation, oral phosphate, and/or magnesium supplementation, in case of persistent hypophosphatemia/hypomagnesemia, and treatment with active vitamin D in cases of persistent secondary hyperparathyroidism. The latter should be done using the minimum PTH-suppressive dosages aiming at the recommended CKD stage-dependent PTH target range. Finally, treatment with recombinant human growth hormone should be considered in patients lacking catch-up growth within the first year after transplantation.
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Affiliation(s)
- Dieter Haffner
- Department of Paediatric Kidney, Liver and Metabolic Diseases, Paediatric Research Center, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
| | - Maren Leifheit-Nestler
- Department of Paediatric Kidney, Liver and Metabolic Diseases, Paediatric Research Center, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.,Paediatric Research Center, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
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9
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Mace ML, Olgaard K, Lewin E. New Aspects of the Kidney in the Regulation of Fibroblast Growth Factor 23 (FGF23) and Mineral Homeostasis. Int J Mol Sci 2020; 21:E8810. [PMID: 33233840 PMCID: PMC7699902 DOI: 10.3390/ijms21228810] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 11/16/2020] [Accepted: 11/19/2020] [Indexed: 02/07/2023] Open
Abstract
The bone-derived hormone fibroblast growth factor 23 (FGF23) acts in concert with parathyroid hormone (PTH) and the active vitamin D metabolite calcitriol in the regulation of calcium (Ca) and phosphate (P) homeostasis. More factors are being identified to regulate FGF23 levels and the endocrine loops between the three hormones. The present review summarizes the complex regulation of FGF23 and the disturbed FGF23/Klotho system in chronic kidney disease (CKD). In addition to the reduced ability of the injured kidney to regulate plasma levels of FGF23, several CKD-related factors have been shown to stimulate FGF23 production. The high circulating FGF23 levels have detrimental effects on erythropoiesis, the cardio-vascular system and the immune system, all contributing to the disturbed system biology in CKD. Moreover, new factors secreted by the injured kidney and the uremic calcified vasculature play a role in the mineral and bone disorder in CKD and create a vicious pathological crosstalk.
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Affiliation(s)
- Maria L. Mace
- Department of Nephrology, Rigshospitalet, University of Copenhagen, 2100 Copenhagen, Denmark; (K.O.); (E.L.)
| | - Klaus Olgaard
- Department of Nephrology, Rigshospitalet, University of Copenhagen, 2100 Copenhagen, Denmark; (K.O.); (E.L.)
| | - Ewa Lewin
- Department of Nephrology, Rigshospitalet, University of Copenhagen, 2100 Copenhagen, Denmark; (K.O.); (E.L.)
- Department of Nephrology, Herlev Hospital, University of Copenhagen, 2730 Herlev, Denmark
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10
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The use of cinacalcet after pediatric renal transplantation: an international CERTAIN Registry analysis. Pediatr Nephrol 2020; 35:1707-1718. [PMID: 32367310 DOI: 10.1007/s00467-020-04558-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 03/18/2020] [Accepted: 03/27/2020] [Indexed: 10/24/2022]
Abstract
BACKGROUND Secondary hyperparathyroidism (SHPT) may persist after renal transplantation (RTx), inducing hypophosphatemia and hypercalcemia that precludes the use of vitamin D analogs. The calcimimetic cinacalcet improved plasma calcium and parathyroid hormone (PTH) levels in randomized controlled trials in adults after RTx, but pediatric data are scarce. METHODS In this retrospective study, we analyzed 20 pediatric patients from the Cooperative European Paediatric Renal TransplAnt Initiative (CERTAIN) Registry who received cinacalcet after RTx. The results are presented as median and interquartile range (25th-75th percentile). RESULTS At 13.7 (11.0-16.5) years of age, 20 pediatric patients received a renal allograft. Cinacalcet was introduced at 0.4 (0.3-2.7) years post-transplant at an estimated glomerular filtration rate (eGFR) of 50 (34-66) mL/min/1.73 m2, plasma calcium of 2.58 (2.39-2.71) mmol/L, age-standardized (z score) phosphate of - 1.7 (- 2.7-- 0.4), and PTH of 136 (95-236) ng/L. The starting dose of cinacalcet was 0.5 (0.3-0.8) mg/kg per day, with a maximum dose of 1.1 (0.5-1.3) mg/kg per day. With a follow-up of 3.0 (1.5-3.6) years on cinacalcet therapy, eGFR remained stable; PTH levels decreased to 66 (56-124) ng/L at the last follow-up (p = 0.015). One patient displayed hypocalcemia (1.8 mmol/L). Cinacalcet was withdrawn in three patients (hypocalcemia, parathyroidectomy, incompliance). Nephrocalcinosis of the graft was not reported. CONCLUSIONS This pilot study suggests that cinacalcet as off-label therapy for SHPT after pediatric RTx is efficacious in controlling post-transplant SHPT with acceptable tolerability. Continuing cinacalcet even with normal PTH can lead to dangerous life-threatening hypocalcemia. Therefore, at each subsequent visit, the need to continue cinacalcet must be assessed.
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11
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Ewert A, Leifheit-Nestler M, Hohenfellner K, Büscher A, Kemper MJ, Oh J, Billing H, Thumfart J, Stangl G, Baur AC, Föller M, Feger M, Weber LT, Acham-Roschitz B, Arbeiter K, Tönshoff B, Zivicnjak M, Haffner D. Bone and Mineral Metabolism in Children with Nephropathic Cystinosis Compared with other CKD Entities. J Clin Endocrinol Metab 2020; 105:5837710. [PMID: 32413117 DOI: 10.1210/clinem/dgaa267] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 05/08/2020] [Indexed: 02/06/2023]
Abstract
CONTEXT Children with nephropathic cystinosis (NC) show persistent hypophosphatemia, due to Fanconi syndrome, as well as mineral and bone disorders related to chronic kidney disease (CKD); however, systematic analyses are lacking. OBJECTIVE To compare biochemical parameters of bone and mineral metabolism between children with NC and controls across all stages of CKD. DESIGN Cross-sectional multicenter study. SETTING Hospital clinics. PATIENTS Forty-nine children with NC, 80 CKD controls of the same age and CKD stage. MAIN OUTCOME MEASURES Fibroblast growth factor 23 (FGF23), soluble Klotho, bone alkaline phosphatase (BAP), tartrate-resistant acid phosphatase 5b (TRAP5b), sclerostin, osteoprotegerin (OPG), biochemical parameters related to mineral metabolism, and skeletal comorbidity. RESULTS Despite Fanconi syndrome medication, NC patients showed an 11-fold increased risk of short stature, bone deformities, and/or requirement for skeletal surgery compared with CKD controls. This was associated with a higher frequency of risk factors such as hypophosphatemia, hypocalcemia, low parathyroid hormone (PTH), metabolic acidosis, and a specific CKD stage-dependent pattern of bone marker alterations. Pretransplant NC patients in mild to moderate CKD showed a delayed increase or lacked an increase in FGF23 and sclerostin, and increased BAP, TRAP5b, and OPG concentrations compared with CKD controls. Post-transplant, BAP and OPG returned to normal, TRAP5b further increased, whereas FGF23 and PTH were less elevated compared with CKD controls and associated with higher serum phosphate. CONCLUSIONS Patients with NC show more severe skeletal comorbidity associated with distinct CKD stage-dependent alterations of bone metabolism than CKD controls, suggesting impaired mineralization and increased bone resorption, which is only partially normalized after renal transplantation.
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Affiliation(s)
- Annika Ewert
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School Children's Hospital, Hannover, Germany
| | - Maren Leifheit-Nestler
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School Children's Hospital, Hannover, Germany
| | | | - Anja Büscher
- Department of Pediatrics II, University Hospital Essen, Essen, Germany
| | | | - Jun Oh
- Division of Pediatric Nephrology, University Children's Hospital Hamburg, Hamburg, Germany
| | - Heiko Billing
- Division of Pediatric Nephrology, University Children's Hospital Tübingen, Tübingen, Germany
| | - Julia Thumfart
- Department of Pediatric Gastroenterology, Nephrology and Metabolism, Charite Hospital, Berlin, Germany
| | - Gabriele Stangl
- Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Anja C Baur
- Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Michael Föller
- Institute of Physiology, University of Hohenheim, Stuttgart, Germany
| | - Martina Feger
- Institute of Physiology, University of Hohenheim, Stuttgart, Germany
| | - Lutz T Weber
- Division of Pediatric Nephrology, Children´s and Adolescents´ Hospital, University of Cologne, Faculty of Medicine and University Hospital, Cologne, Germany
| | | | - Klaus Arbeiter
- Division of Pediatric Nephrology and Gastroenterology, Medical University Vienna, Austria
| | - Burkhard Tönshoff
- Department of Pediatrics I, University Children's Hospital Heidelberg, Heidelberg, Germany
| | - Miroslav Zivicnjak
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School Children's Hospital, Hannover, Germany
| | - Dieter Haffner
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School Children's Hospital, Hannover, Germany
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12
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Abstract
Acute kidney injury (AKI) is associated with many of the same mineral metabolite abnormalities that are observed in chronic kidney disease. These include increased circulating levels of the osteocyte-derived, vitamin D-regulating hormone, fibroblast growth factor 23 (FGF23), and decreased renal expression of klotho, the co-receptor for FGF23. Recent data have indicated that increased FGF23 and decreased klotho levels in the blood and urine could serve as novel predictive biomarkers of incident AKI, or as novel prognostic biomarkers of adverse outcomes in patients with established AKI. In addition, because FGF23 and klotho exert numerous classic as well as off-target effects on a variety of organ systems, targeting their dysregulation in AKI may represent a unique opportunity for therapeutic intervention. We review the pathophysiology, kinetics, and regulation of FGF23 and klotho in animal and human studies of AKI, and we discuss the challenges and opportunities involved in targeting FGF23 and klotho therapeutically.
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Affiliation(s)
- Marta Christov
- Department of Medicine, New York Medical College, Valhalla, NY.
| | - Javier A Neyra
- Division of Nephrology, Bone and Mineral Metabolism, Department of Internal Medicine, University of Kentucky, Lexington, KY; Division of Nephrology, Department of Internal Medicine, University of Texas Southwestern, Dallas, TX
| | - Sanjeev Gupta
- Department of Medicine, New York Medical College, Valhalla, NY
| | - David E Leaf
- Division of Renal Medicine, Brigham and Women's Hospital, Boston, MA
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13
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Prytuła A, Cransberg K, Raes A. Drug-metabolizing enzymes CYP3A as a link between tacrolimus and vitamin D in renal transplant recipients: is it relevant in clinical practice? Pediatr Nephrol 2019; 34:1201-1210. [PMID: 30058048 DOI: 10.1007/s00467-018-4030-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 07/10/2018] [Accepted: 07/20/2018] [Indexed: 01/08/2023]
Abstract
CYP3A enzymes are involved in the metabolism of calcineurin inhibitor tacrolimus as well as vitamin D. In this review, we summarize the clinical aspects of CYP3A-mediated metabolism of tacrolimus and vitamin D with emphasis on the influence of single-nucleotide polymorphisms on tacrolimus disposition. We describe the utility of 4β hydroxycholesterol as a marker of CYP3A activity. Then, we discuss the possible interaction between calcineurin inhibitors and vitamin D in solid organ transplant recipients. Also, we review other mechanisms which may contribute to side effects of calcineurin inhibitors on bone. Lastly, suggestions for future research and clinical perspectives are discussed.
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Affiliation(s)
- Agnieszka Prytuła
- Paediatric Nephrology and Rheumatology Department, Ghent University Hospital, C Heymanslaan 10, 9000, Ghent, Belgium.
| | - Karlien Cransberg
- Paediatric Nephrology Department, Erasmus MC- Sophia Children's Hospital, Rotterdam, the Netherlands
| | - Ann Raes
- Paediatric Nephrology and Rheumatology Department, Ghent University Hospital, C Heymanslaan 10, 9000, Ghent, Belgium.,Safepedrug Unit, Ghent, Belgium
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14
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Pathogenesis and treatment of electrolyte problems post transplant. Curr Opin Pediatr 2019; 31:213-218. [PMID: 30585865 DOI: 10.1097/mop.0000000000000715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE OF REVIEW Electrolyte abnormalities posttransplant are common occurrences that can have significant short-term and long-term effects on graft outcome and patient quality of life. Understanding the pathophysiology of these electrolyte derangements can help guide management to optimize bone health and minimize cardiovascular disease. This review explores the pathogenesis of the most common postrenal transplant electrolytes abnormalities as well as current treatment options. RECENT FINDINGS Clarifications of the role of FGF-23 has improved our understanding of posttransplant bone disease in addition to the known roles of hyperparathyroidism and vitamin D. The mechanisms of renal electrolyte wasting by immunosuppressive agents give insight into potential treatment options for hyperkalemia and hypomagnesemia. SUMMARY Understanding the pathogenesis of the common electrolyte abnormalities found post renal transplant may lead to targeted treatment options that in turn may improve transplant complications. Further studies are required to evaluate the effects on long-term outcomes of renal allografts.
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15
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Abstract
Renal transplantation is the preferred treatment for patients with end-stage kidney disease. However, despite successful kidney transplantation, cardiovascular disease (CVD) remains one of the major causes of patient death and hence graft loss. The antecedents of this increased risk reside within the development of end-stage kidney disease and dialysis. Risk factors for the development of CVD include diabetes, hypertension, and dyslipidemia. Other transplant-specific factors include the presence of a patent arteriovenous fistula and immunosuppressive therapy. Efforts to modify these factors should be strongly encouraged to improve long-term outcomes of transplant patients and reduce death from CVD in this at-risk patient population.
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Affiliation(s)
- Nitesh N Rao
- Renal Unit, Lyell McEwin Hospital, Elizabeth Vale, South Australia
| | - P Toby Coates
- Renal Unit, Lyell McEwin Hospital, Elizabeth Vale, South Australia; Central Northern Adelaide Renal and Transplantation Service, Royal Adelaide Hospital, Adelaide, South Australia.
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16
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Damasiewicz MJ, Lu ZX, Kerr PG, Polkinghorne KR. The stability and variability of serum and plasma fibroblast growth factor-23 levels in a haemodialysis cohort. BMC Nephrol 2018; 19:325. [PMID: 30428848 PMCID: PMC6236962 DOI: 10.1186/s12882-018-1127-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2017] [Accepted: 10/31/2018] [Indexed: 01/07/2023] Open
Abstract
Background Serum fibroblast growth factor 23 (FGF-23) levels are markedly elevated in haemodialysis patients and have been linked to mortality outcomes. Small studies in health and chronic kidney disease, have demonstrated marked intra- and inter-individual variability in measured FGF-23 levels, and variable degradation in serum as compared to plasma samples. In end-stage kidney disease (ESKD), the intra- and inter-individual variability of FGF-23 levels, and the optimal collection methods remain poorly characterized. In this study we assessed the variability of FGF-23 levels in a cohort of stable haemodialysis patients. Secondly, in a subset of patients, we assessed the effects of different collection methods on measured FGF-23 levels. Methods To assess the variability of FGF-23, pre-dialysis blood samples were collected over 3 consecutive weeks from 75 haemodialysis patients. The effects of different specimen collection methods were examined in a subset of patients (n = 23), with pre-dialysis blood collected into different tubes: plain (serum), EDTA (plasma) and EDTA with the addition of a protease inhibitor (EDTA-PI). All analyses were performed in the main cohort and repeated in each subgroup. Variability over a 3-week period was assessed using repeated measures ANOVA and random effects linear regression models. Intra-class correlation coefficients were calculated to assess agreement, and coefficients of variation were calculated to assess intra- and inter-individual variability. Results Over the 3-week study period the mean FGF-23 levels were not significantly different in the serum (p = 0.26), EDTA (p = 0.62) and EDTA-PI (p = 0.55) groups. FGF-23 levels demonstrated marked intra- and inter-individual variability with a CV of 36 and 203.2%, respectively. In the subgroup analysis, the mean serum FGF-23 levels were significantly lower than the EDTA (p < 0.001) or EDTA-PI (p < 0.001) groups, however there was no difference in mean FGF-23 levels between EDTA and EDTA-PI (p = 0.54). Conclusions The measured FGF-23 levels were significantly lower in serum as compared to plasma, and the addition of a protease inhibitor did not confer an additional benefit. Importantly in this cohort of ESKD patients, FGF-23 levels showed marked intra- and inter-individual variability. The routine measurement of FGF-23 in ESKD remains challenging, however this study suggests the plasma is the optimal collection method for FGF-23 analysis.
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Affiliation(s)
- Matthew J Damasiewicz
- Department of Nephrology, Monash Medical Centre, Monash Health, Clayton, VIC, Australia. .,Department of Medicine, Monash University, Clayton, VIC, Australia.
| | - Zhong X Lu
- Department of Medicine, Monash University, Clayton, VIC, Australia.,Monash Pathology, Monash Health, Clayton, VIC, Australia
| | - Peter G Kerr
- Department of Nephrology, Monash Medical Centre, Monash Health, Clayton, VIC, Australia.,Department of Medicine, Monash University, Clayton, VIC, Australia
| | - Kevan R Polkinghorne
- Department of Nephrology, Monash Medical Centre, Monash Health, Clayton, VIC, Australia.,Department of Medicine, Monash University, Clayton, VIC, Australia.,Department of Epidemiology and Preventive Medicine, Monash University, Prahran, VIC, Australia
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17
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Yadav AK, Ramachandran R, Aggarwal A, Kumar V, Gupta KL, Jha V. Fibroblast growth factor 23 in untreated nephrotic syndrome. Nephrology (Carlton) 2018; 23:362-365. [PMID: 28087977 DOI: 10.1111/nep.13001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 01/02/2017] [Accepted: 01/11/2017] [Indexed: 01/24/2023]
Abstract
AIM Despite its importance in bone and cardiovascular disease in subjects with kidney disease, there are no data on fibroblast growth factor 23 (FGF23) perturbations in nephrotic syndrome. We evaluated FGF23 and markers of mineral bone metabolism in subjects with untreated NS. METHODS In this cross-sectional study, we measured circulating levels of FGF23, 25-hydroxy vitamin D [25(OH)D], 1,25 di-hydroxy vitamin D [1,25(OH)2 D], serum albumin, serum calcium, phosphorus, creatinine and intact parathyroid hormone (iPTH) in 101 patients with adults onset NS and 40 healthy controls. We examined the correlation between FGF23 and markers of mineral bone metabolism. RESULTS Compared to healthy controls, subjects with NS showed reduced levels of 25(OH)D (21.76 ± 10.18 vs 35.74 ± 40.27 nmol/L, P = 0.001), 1,25(OH)2 D (median; 37.80 vs 73.13 pmol/L, P = 0.0001) and FGF23 (37.81 ± 20.42 vs 48.20 ± 11.60 pg/mL, P = 0.004) levels. Serum phosphorus levels were marginally, but significantly higher in subjects with nephrotic syndrome compared to healthy controls (P = 0.004). Serum iPTH levels were significantly higher in subjects with NS compared to healthy controls (52.24 ± 39.58 vs 37.90 ± 14.60 pg/mL, P = 0.028). CONCLUSIONS We conclude that FGF23 is reduced in subjects with NS compared to healthy controls. The reduced levels of Vitamin D, and urinary losses may contribute to lower levels of FGF23 in NS.
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Affiliation(s)
| | | | - Abhinav Aggarwal
- Department of Internal Medicine and Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | | | | | - Vivekanand Jha
- Department of Nephrology, Chandigarh, India.,George Institute for Global Health, 219-221 Splendor Forum, New Delhi
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18
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CYP3A4 is a crosslink between vitamin D and calcineurin inhibitors in solid organ transplant recipients: implications for bone health. THE PHARMACOGENOMICS JOURNAL 2017; 17:481-487. [PMID: 28418012 DOI: 10.1038/tpj.2017.15] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2016] [Revised: 12/23/2016] [Accepted: 01/18/2017] [Indexed: 11/08/2022]
Abstract
The use of calcineurin inhibitors (CNIs) and vitamin D deficiency may contribute to the pathogenesis of post-transplant bone disease. CNIs and 1,25-dihydroxyvitamin D₃ (1,25(OH)2D3) are substrates of the drug-metabolizing enzyme CYP3A4. This review summarizes the indications for the use of activated vitamin D analogs in post-transplant care and the current knowledge on the impact of CNIs on bone. We searched for clinical evidence of the interaction between CNIs and 1,25(OH)2D3. We also provide an overview of the literature on the interplay between vitamin D metabolism and CYP3A4 in experimental and clinical settings and discuss its possible implications for solid organ transplant recipients. In conclusion, there is a body of evidence on the interplay between vitamin D and the drug-metabolizing enzyme CYP3A4, which may have therapeutic implications.
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19
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Tan SJ, Crosthwaite A, Langsford D, Obeysekere V, Ierino FL, Roberts MA, Hughes PD, Hewitson TD, Dwyer KM, Toussaint ND. Mineral adaptations following kidney transplantation. Transpl Int 2017; 30:463-473. [PMID: 28120476 DOI: 10.1111/tri.12925] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 10/28/2016] [Accepted: 01/18/2017] [Indexed: 12/30/2022]
Abstract
Klotho is predominantly expressed in the kidney and reported to have antioxidant and antifibrotic properties. Soluble Klotho (sKl), the circulating protein cleaved from membrane-bound Klotho, is reduced significantly with kidney disease and inversely associated with mortality. sKl has not been thoroughly evaluated prospectively after kidney transplantation. Incident kidney transplant recipients (KTRs) were prospectively evaluated pretransplantation, 1, 12 and 52 weeks post-transplantation. Basic biochemistry, sKl and intact FGF23 were measured. Within-subject comparisons were evaluated using repeat-measure anova or Friedman's analysis. Effects of immunosuppression and biochemical parameters on sKl and FGF-23 over time were analysed using mixed-effects modelling. Median serum creatinine (sCr) at 1 week was 116 (92-142) μmol/l, and at 52 weeks, all 29 KTRs had a functioning graft with median sCr of 111 (97-131) μmol/l. Compared with baseline, sKl was increased at 52 weeks following an initial decline at 1 week (P < 0.005 and P < 0.01, respectively), while FGF23 was considerably reduced at 52 weeks (P < 0.001). In a mixed-effects model, an increased sKl was not associated with reduction in immunosuppression or evaluated biochemical parameters. Modest increase in sKl is observed one-year postkidney transplantation with excellent early graft function suggesting factors beyond renal capacity may influence circulating sKl. FGF23 normalization was observed. Longer term evaluation in transplantation, specifically addressing the effects of immunosuppression, is required to understand the pathophysiology of the sKl/FGF23 axis and potential for modification.
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Affiliation(s)
- Sven-Jean Tan
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Vic., Australia.,Department of Medicine, The University of Melbourne, Parkville, Vic., Australia
| | - Amy Crosthwaite
- Department of Medicine, The University of Melbourne, Parkville, Vic., Australia.,Department of Nephrology, Austin Hospital, Heidelberg, Vic., Australia
| | - David Langsford
- Department of Nephrology, Northern Hospital, Epping, Vic., Australia
| | - Varuni Obeysekere
- Department of Endocrinology, St Vincent's Hospital Melbourne, Fitzroy, Vic., Australia
| | - Frank L Ierino
- Department of Medicine, The University of Melbourne, Parkville, Vic., Australia.,Department of Nephrology, St Vincent's Hospital Melbourne, Fitzroy, Vic., Australia.,Victorian Kidney Transplantation Collaborative, Melbourne, Vic., Australia
| | - Matthew A Roberts
- Victorian Kidney Transplantation Collaborative, Melbourne, Vic., Australia.,Eastern Health Clinical School, Monash University, Box Hill, Vic., Australia
| | - Peter D Hughes
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Vic., Australia.,Department of Medicine, The University of Melbourne, Parkville, Vic., Australia
| | - Tim D Hewitson
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Vic., Australia.,Department of Medicine, The University of Melbourne, Parkville, Vic., Australia
| | - Karen M Dwyer
- Department of Medicine, The University of Melbourne, Parkville, Vic., Australia.,Department of Nephrology, St Vincent's Hospital Melbourne, Fitzroy, Vic., Australia.,Victorian Kidney Transplantation Collaborative, Melbourne, Vic., Australia.,School of Medicine, Deakin University, Geelong, Vic., Australia
| | - Nigel D Toussaint
- Department of Nephrology, The Royal Melbourne Hospital, Parkville, Vic., Australia.,Department of Medicine, The University of Melbourne, Parkville, Vic., Australia
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20
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Leaf DE, Jacob KA, Srivastava A, Chen ME, Christov M, Jüppner H, Sabbisetti VS, Martin A, Wolf M, Waikar SS. Fibroblast Growth Factor 23 Levels Associate with AKI and Death in Critical Illness. J Am Soc Nephrol 2016; 28:1877-1885. [PMID: 28028134 DOI: 10.1681/asn.2016080836] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 11/21/2016] [Indexed: 01/24/2023] Open
Abstract
Elevated plasma levels of the osteocyte-derived hormone fibroblast growth factor 23 (FGF23) have emerged as a powerful biomarker of cardiovascular disease and death in patients with CKD. Whether elevated urinary or plasma FGF23 levels are prospectively associated with AKI and death in critically ill patients is unknown. We therefore conducted a prospective cohort study of 350 critically ill patients admitted to intensive care units at an academic medical center to investigate whether higher urinary FGF23 levels associate with the composite end point of AKI or in-hospital mortality (AKI/death). We measured urinary FGF23 levels within 24 hours of admission to the intensive care unit. In a subcohort (n=131) we also measured plasma levels of FGF23, calcium, phosphate, parathyroid hormone, and vitamin D metabolites. Urinary and plasma FGF23 levels, but not other mineral metabolites, significantly associated with AKI/death. In multivariate analyses, patients in the highest compared with the lowest quartile of urinary FGF23 had a 3.9 greater odds (95% confidence interval, 1.6 to 9.5) of AKI/death. Higher urinary FGF23 levels also independently associated with greater hospital, 90-day, and 1-year mortality; longer length of stay; and several other important adverse outcomes. In conclusion, elevated FGF23 levels measured in the urine or plasma may be a promising novel biomarker of AKI, death, and other adverse outcomes in critically ill patients.
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Affiliation(s)
- David E Leaf
- Division of Renal Medicine, Brigham and Women's Hospital, Boston, Massachusetts;
| | - Kirolos A Jacob
- Department of Cardiothoracic Surgery, University Medical Center, Utrecht, Utrecht, The Netherlands
| | - Anand Srivastava
- Division of Renal Medicine, Brigham and Women's Hospital, Boston, Massachusetts
| | - Margaret E Chen
- Division of Renal Medicine, Brigham and Women's Hospital, Boston, Massachusetts
| | - Marta Christov
- Endocrine Unit and Pediatric Nephrology Unit, Massachusetts General Hospital, Boston, Massachusetts.,Department of Medicine, New York Medical College, Valhalla, New York
| | - Harald Jüppner
- Endocrine Unit and Pediatric Nephrology Unit, Massachusetts General Hospital, Boston, Massachusetts
| | | | - Aline Martin
- Division of Nephrology and Hypertension, Department of Medicine and Center for Translational Metabolism and Health, Institute for Public Health and Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois; and
| | - Myles Wolf
- Division of Nephrology, Department of Medicine, Duke University School of Medicine, Durham, North Carolina
| | - Sushrut S Waikar
- Division of Renal Medicine, Brigham and Women's Hospital, Boston, Massachusetts
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21
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Abstract
The last 25 years have been characterized by dramatic improvements in short-term patient and allograft survival after kidney transplantation. Long-term patient and allograft survival remains limited by cardiovascular disease and chronic allograft injury, among other factors. Cardiovascular disease remains a significant contributor to mortality in native chronic kidney disease as well as cardiovascular mortality in chronic kidney disease more than doubles that of the general population. The chronic kidney disease (CKD)-mineral bone disorder (MBD) is a syndrome recently coined to embody the biochemical, skeletal, and cardiovascular pathophysiology that results from disrupting the complex systems biology between the kidney, skeleton, and cardiovascular system in native and transplant kidney disease. The CKD-MBD is a unique kidney disease-specific syndrome containing novel cardiovascular risk factors, with an impact reaching far beyond traditional notions of renal osteodystrophy and hyperparathyroidism. This overview reviews current knowledge of the pathophysiology of the CKD-MBD, including emerging concepts surrounding the importance of circulating pathogenic factors released from the injured kidney that directly cause cardiovascular disease in native and transplant chronic kidney disease, with potential application to mechanisms of chronic allograft injury and vasculopathy.
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22
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Left ventricular mass and cardiac function in pediatric dialysis patients. PROGRESS IN PEDIATRIC CARDIOLOGY 2016. [DOI: 10.1016/j.ppedcard.2015.11.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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23
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Leifheit-Nestler M, Große Siemer R, Flasbart K, Richter B, Kirchhoff F, Ziegler WH, Klintschar M, Becker JU, Erbersdobler A, Aufricht C, Seeman T, Fischer DC, Faul C, Haffner D. Induction of cardiac FGF23/FGFR4 expression is associated with left ventricular hypertrophy in patients with chronic kidney disease. Nephrol Dial Transplant 2015; 31:1088-99. [PMID: 26681731 DOI: 10.1093/ndt/gfv421] [Citation(s) in RCA: 149] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 11/18/2015] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND In chronic kidney disease (CKD), serum concentrations of fibroblast growth factor 23 (FGF23) increase progressively as glomerular filtration rate declines, while renal expression of the FGF23 coreceptor Klotho decreases. Elevated circulating FGF23 levels are strongly associated with mortality and with left ventricular hypertrophy (LVH), which is a major cause of cardiovascular death in CKD patients. The cardiac FGF23/FGF receptor (FGFR) system and its role in the development of LVH in humans have not been addressed previously. METHODS We conducted a retrospective case-control study in 24 deceased patients with childhood-onset end-stage renal disease (dialysis: n = 17; transplanted: n = 7), and 24 age- and sex-matched control subjects. Myocardial autopsy samples of the left ventricle were evaluated for expression of endogenous FGF23, FGFR isoforms, Klotho, calcineurin and nuclear factor of activated T-cells (NFAT) by immunohistochemistry, immunofluorescence microscopy, qRT-PCR and western blotting. RESULTS The majority of patients presented with LVH (67%). Human cardiomyocytes express full-length FGF23, and cardiac FGF23 is excessively high in patients with CKD. Enhanced myocardial expression of FGF23 in concert with Klotho deficiency strongly correlates with the presence of LVH. Cardiac FGF23 levels associate with time-averaged serum phosphate levels, up-regulation of FGFR4 and activation of the calcineurin-NFAT signaling pathway, an established mediator of cardiac remodelling and LVH. These changes are detected in patients on dialysis but not in those with a functioning kidney transplant. CONCLUSIONS Our results indicate a strong association between LVH and enhanced expression levels of FGF23, FGFR4 and calcineurin, activation of NFAT and reduced levels of soluble Klotho in the myocardium of patients with CKD. These alterations are not observed in kidney transplant patients.
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Affiliation(s)
- Maren Leifheit-Nestler
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Robert Große Siemer
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Kathrin Flasbart
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Beatrice Richter
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Felix Kirchhoff
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Wolfgang H Ziegler
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Michael Klintschar
- Institute for Forensic Medicine, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Jan U Becker
- Institute of Pathology, University Hospital Cologne, Kerpener Str. 62, 50937 Cologne, Germany
| | - Andreas Erbersdobler
- Institute of Pathology, University Hospital Rostock, Strempelstr. 14, 18055 Rostock, Germany
| | - Christoph Aufricht
- Division of Pediatric Nephrology, University Children's Hospital Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - Tomas Seeman
- Division of Pediatric Nephrology, University Children's Hospital Motol, V Uvalu 84, 15006, Prague, Czech Republic
| | - Dagmar-Christiane Fischer
- Department of Pediatrics, University Hospital Rostock, Ernst-Heydemann-Str. 8, 18057 Rostock, Germany
| | - Christian Faul
- Division of Nephrology and Hypertension, Department of Medicine, University of Miami Miller School of Medicine, 1580 NW 10th Avenue (R-762), Miami, FL 33136, USA
| | - Dieter Haffner
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
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24
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Malyszko J, Koc-Zorawska E, Matuszkiewicz-Rowinska J, Malyszko J. FGF23 and Klotho in relation to markers of endothelial dysfunction in kidney transplant recipients. Transplant Proc 2015; 46:2647-50. [PMID: 25380886 DOI: 10.1016/j.transproceed.2014.09.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND Fibroblast growth factor (FGF) 23 is a newly discovered member of the FGF family. Klotho is a cofactor of FGF23. Activation of the FGF23-Klotho system is responsible for negative phosphate balance. In addition, FGF23 appears to be a risk factor for cardiovascular complications. The aim of this study was to assess levels of FGF23 and Klotho in stable kidney transplant recipients on triple immunosuppressive therapy in relation to comorbidities and markers endothelial dysfunction. Healthy volunteers served as a control group. METHODS Hemoglobin, urea, and creatinine were studied with the use of standard laboratory methods in the hospital central laboratory. We assessed FGF23 and Klotho, markers of endothelial function/injury von Willebrand factor (vWF), intercellular adhesion molecule (ICAM), vascular cell adhesion molecule (VCAM), and interleukin (IL) 6, N-terminal pro-B-type natriuretic peptide (NT-proBNP) and copeptin with the use of commercially available assays. RESULTS FGF23 was significantly higher and Klotho significantly lower in kidney transplant recipients compared with healthy volunteers. FGF23 correlated with copeptin (r = 0.28; P < .05), IL-6 (r = 0.39; P < .01), VCAM (r = 0.36; P < .01), time after transplantation (r = 0.31; P < .05), platelet count (r = 0.31; P < .05), mean corpuscular volume (r = -0.40; P < .01), and phosphate (r = 0.31; P < .05). Klotho correlated with NT-proBNP (r = 0.38; P < .01), vWF (r = -0.26; P < .05), calcium (r = -0.39; P < .01), and age (r = 0.45; P < .001). FGF23 was significantly higher and Klotho significantly lower in patients with estimated glomerular filtration rate (eGFR) >60 mL/min compared with patients with eGFR <60 mL/min. CONCLUSIONS Disturbances in the FGF23-Klotho system appeared to be related to the endothelial cell injury. Thus they are involved not only in pathogenesis of the metabolic bone disease but also in cardiovascular complications, particularly in kidney disease.
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Affiliation(s)
- Jolanta Malyszko
- 2nd Department of Nephrology, Medical University, Bialystok, Poland.
| | - E Koc-Zorawska
- 2nd Department of Nephrology, Medical University, Bialystok, Poland
| | - J Matuszkiewicz-Rowinska
- Department of Nephrology, Internal Medicine and Dialysis Therapy, Medical University, Warsaw, Poland
| | - Jacek Malyszko
- 2nd Department of Nephrology, Medical University, Bialystok, Poland
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25
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Abstract
Dysregulated phosphate metabolism is a common consequence of chronic kidney disease, and is characterized by a high circulating level of fibroblast growth factor (FGF)-23, hyperparathyroidism, and hyperphosphataemia. Kidney transplantation can elicit specific alterations to phosphate metabolism that evolve over time, ranging from severe hypophosphataemia (<0.5 mmol/l) to hyperphosphataemia (>1.50 mmol/l) and high FGF-23 levels. The majority of renal transplant recipients develop hypophosphataemia during the first 3 months after transplantation as a consequence of relatively slow adaptation of FGF-23 and parathyroid hormone levels to restored renal function, and the influence of immunosuppressive drugs. By 3-12 months after transplantation, phosphate homeostasis is at least partially restored in the majority of recipients, which is paralleled by a substantially reduced risk of cardiovascular-associated morbidity and mortality compared with the pre-transplantation setting. Many renal transplant recipients, however, exhibit persistent abnormalities in phosphate homeostasis, which is often due to multifactorial causes, and may contribute to adverse outcomes on the cardiovascular system, kidney, and bone. Dietary and pharmacologic interventions might improve phosphate homeostasis in renal transplant recipients, but additional insight into the pathophysiology of transplantation-associated abnormalities in phosphate homeostasis is needed to further optimize disease management and improve prognosis for renal transplant recipients.
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26
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Han X, Xiao Z, Quarles LD. Membrane and integrative nuclear fibroblastic growth factor receptor (FGFR) regulation of FGF-23. J Biol Chem 2015; 290:10447-59. [PMID: 25752607 PMCID: PMC4400353 DOI: 10.1074/jbc.m114.609230] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 02/27/2015] [Indexed: 01/15/2023] Open
Abstract
Fibroblastic growth factor receptor 1 (FGFR1) signaling pathways are implicated in the regulation of FGF-23 gene transcription, but the molecular pathways remain poorly defined. We used low molecular weight (LMW, 18 kDa) FGF-2 and high molecular weight (HMW) FGF-2 isoforms, which, respectively, activate cell surface FGF receptors and intranuclear FGFR1, to determine the roles of membrane FGFRs and integrative nuclear FGFR1 signaling (INFS) in the regulation of FGF-23 gene transcription in osteoblasts. We found that LMW-FGF-2 induced NFAT and Ets1 binding to conserved cis-elements in the proximal FGF-23 promoter and stimulated FGF-23 promoter activity through PLCγ/calcineurin/NFAT and MAPK pathways in SaOS-2 and MC3T3-E1 osteoblasts. In contrast, HMW-FGF-2 stimulated FGF-23 promoter activity in osteoblasts through a cAMP-dependent binding of FGFR1 and cAMP-response element-binding protein (CREB) to a conserved cAMP response element (CRE) contiguous with the NFAT binding site in the FGF-23 promoter. Mutagenesis of the NFAT and CRE binding sites, respectively, inhibited the effects of LMW-FGF-2 and HMW-FGF-23 to stimulate FGF-23 promoter activity. FGF-2 activation of both membrane FGFRs and INFS-dependent FGFR1 pathways may provide a means to integrate systemic and local regulation of FGF-23 transcription under diverse physiological and pathological conditions.
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Affiliation(s)
- Xiaobin Han
- From the Department of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee 38163
| | - Zhousheng Xiao
- From the Department of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee 38163
| | - L Darryl Quarles
- From the Department of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee 38163
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27
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Bonthuis M, Busutti M, van Stralen KJ, Jager KJ, Baiko S, Bakkaloğlu S, Battelino N, Gaydarova M, Gianoglio B, Parvex P, Gomes C, Heaf JG, Podracka L, Kuzmanovska D, Molchanova MS, Pankratenko TE, Papachristou F, Reusz G, Sanahuja MJ, Shroff R, Groothoff JW, Schaefer F, Verrina E. Mineral metabolism in European children living with a renal transplant: a European society for paediatric nephrology/european renal association-European dialysis and transplant association registry study. Clin J Am Soc Nephrol 2015; 10:767-75. [PMID: 25710805 DOI: 10.2215/cjn.06200614] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 01/13/2015] [Indexed: 11/23/2022]
Abstract
BACKGROUND AND OBJECTIVES Data on mineral metabolism in pediatric renal transplant recipients largely arise from small single-center studies. In adult patients, abnormal mineral levels are related to a higher risk of graft failure. This study used data from the European Society for Paediatric Nephrology/European Renal Association-European Dialysis and Transplant Association Registry to study the prevalence and potential determinants of mineral abnormalities, as well as the predictive value of a disturbed mineral level on graft survival in a large cohort of European pediatric renal transplant recipients. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS This study included 1237 children (0-17 years) from 10 European countries, who had serum calcium, phosphorus, and parathyroid hormone measurements from 2000 onward. Abnormalities of mineral metabolism were defined according to European guidelines on prevention and treatment of renal osteodystrophy in children on chronic renal failure. RESULTS Abnormal serum phosphorus levels were observed in 25% (14% hypophosphatemia and 11% hyperphosphatemia), altered serum calcium in 30% (19% hypocalcemia, 11% hypercalcemia), and hyperparathyroidism in 41% of the patients. A longer time since transplantation was associated with a lower risk of having mineral levels above target range. Serum phosphorus levels were inversely associated with eGFR, and levels above the recommended targets were associated with a higher risk of graft failure independently of eGFR. CONCLUSIONS Abnormalities in mineral metabolism are common after pediatric renal transplantation in Europe and are associated with graft dysfunction.
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Affiliation(s)
- Marjolein Bonthuis
- Due to the number of contributing authors,the affiliations are provided in the Supplemental Material
| | - Marco Busutti
- Due to the number of contributing authors,the affiliations are provided in the Supplemental Material
| | - Karlijn J van Stralen
- Due to the number of contributing authors,the affiliations are provided in the Supplemental Material.
| | - Kitty J Jager
- Due to the number of contributing authors,the affiliations are provided in the Supplemental Material
| | - Sergey Baiko
- Due to the number of contributing authors,the affiliations are provided in the Supplemental Material
| | - Sevcan Bakkaloğlu
- Due to the number of contributing authors,the affiliations are provided in the Supplemental Material
| | - Nina Battelino
- Due to the number of contributing authors,the affiliations are provided in the Supplemental Material
| | - Maria Gaydarova
- Due to the number of contributing authors,the affiliations are provided in the Supplemental Material
| | - Bruno Gianoglio
- Due to the number of contributing authors,the affiliations are provided in the Supplemental Material
| | - Paloma Parvex
- Due to the number of contributing authors,the affiliations are provided in the Supplemental Material
| | - Clara Gomes
- Due to the number of contributing authors,the affiliations are provided in the Supplemental Material
| | - James G Heaf
- Due to the number of contributing authors,the affiliations are provided in the Supplemental Material
| | - Ludmila Podracka
- Due to the number of contributing authors,the affiliations are provided in the Supplemental Material
| | - Dafina Kuzmanovska
- Due to the number of contributing authors,the affiliations are provided in the Supplemental Material
| | - Maria S Molchanova
- Due to the number of contributing authors,the affiliations are provided in the Supplemental Material
| | - Tatiana E Pankratenko
- Due to the number of contributing authors,the affiliations are provided in the Supplemental Material
| | - Fotios Papachristou
- Due to the number of contributing authors,the affiliations are provided in the Supplemental Material
| | - György Reusz
- Due to the number of contributing authors,the affiliations are provided in the Supplemental Material
| | - Maria José Sanahuja
- Due to the number of contributing authors,the affiliations are provided in the Supplemental Material
| | - Rukshana Shroff
- Due to the number of contributing authors,the affiliations are provided in the Supplemental Material
| | - Jaap W Groothoff
- Due to the number of contributing authors,the affiliations are provided in the Supplemental Material
| | - Franz Schaefer
- Due to the number of contributing authors,the affiliations are provided in the Supplemental Material
| | - Enrico Verrina
- Due to the number of contributing authors,the affiliations are provided in the Supplemental Material
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28
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Abstract
The emergence of fibroblast growth factor 23 as a potentially modifiable risk factor in CKD has led to growing interest in its measurement as a tool to assess patient risk and target therapy. This review discusses the analytical and clinical challenges faced in translating fibroblast growth factor 23 testing into routine practice. As for other bone mineral markers, agreement between commercial fibroblast growth factor 23 assays is poor, mainly because of differences in calibration, but also, these differences reflect the variable detection of hormone fragments. Direct comparison of readout from different assays is consequently limited and likely hampers setting uniform fibroblast growth factor 23-directed targets. Efforts are needed to standardize assay output to enhance clinical use. Fibroblast growth factor 23 is robustly associated with cardiovascular and renal outcomes in patients with CKD and adds value to risk assessments based on conventional risk factors. Compared with most other mineral markers, fibroblast growth factor 23 shows better intraindividual temporal stability, with minimal diurnal and week-to-week variability, but substantial interindividual variation, maximizing discriminative power for risk stratification. Conventional therapeutic interventions for the CKD-mineral bone disorder, such as dietary phosphate restriction and use of oral phosphate binders or calcimimetics, are associated with variable efficacy at modulating circulating fibroblast growth factor 23 concentrations, like they are for other mineral metabolites. Dual therapy with dietary phosphate restriction and noncalcium-based binder use achieves the most consistent fibroblast growth factor 23-lowering effect and seems best monitored using an intact assay. Additional studies are needed to evaluate whether strategies aimed at reducing levels or antagonizing its action have beneficial effects on clinical outcomes in CKD patients. Moreover, a better understanding of the mechanisms driving fibroblast growth factor 23 elevations in CKD is needed to inform the use of therapeutic interventions targeting fibroblast growth factor 23 excess. This evidence must be forthcoming to support the use of fibroblast growth factor 23 measurement and fibroblast growth factor 23-directed therapy in the clinic.
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Affiliation(s)
- Edward R Smith
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, Victoria, Australia
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29
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Abstract
PURPOSE OF THE REVIEW Posttransplantation mineral and bone disorder (MBD) is an important issue in the care of children after kidney transplantation (KTx) resulting in increased comorbidity, for example, bone pain, fractures, growth failure, and vascular calcifications. It is distinctly different from common forms of osteoporosis and mainly due to preexisting renal osteodystrophy at the time of KTx, glucocorticoid treatment, and reduced graft function. The purpose of this review is to give an overview of the pathogenesis and treatment of posttransplant MBD in children. RECENT FINDINGS Recent studies underline the impact of elevated levels of the phosphaturic hormone fibroblast growth factor-23 on posttransplant MBD. Glucocorticoid treatment results in impairment of bone strength, increased fracture risk, and lack of significant catch up, whereas steroid-sparing protocols allow for a normal adult height in the majority of patients. Whether the latter also improves bone strength remains to be elucidated. SUMMARY Therapeutic efforts to reduce MBD after KTx should focus on steroid-sparing immunosuppressive protocols, adequate treatment of alterations of calcium, phosphate and vitamin D metabolism, maintenance of regular physical activity, and preservation of transplant function. Preemptive KTx, that is with no prior dialysis, can prevent progressive vascular calcifications.
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Affiliation(s)
- Dieter Haffner
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Germany
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