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Lapsina S, Nagler N, Müller SF, Holtdirk A, Kottmann T, Müller E, Schäfer I. Fibroblast Growth Factor-23 (FGF-23) in Dogs-Reference Interval and Correlation with Hematological and Biochemical Parameters. Animals (Basel) 2023; 13:3202. [PMID: 37893926 PMCID: PMC10603748 DOI: 10.3390/ani13203202] [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: 08/05/2023] [Revised: 09/25/2023] [Accepted: 10/10/2023] [Indexed: 10/29/2023] Open
Abstract
Fibroblast growth factor-23 (FGF-23) is a phosphaturic hormone used to monitor chronic kidney disease (CKD) in humans. The aims of this study were (1) to determine the intra- and interassay precision of the FGF-23 concentrations in dogs as measured via the Kainos ELISA FGF-23 kit, (2) to calculate a reference interval, and (3) to assess the correlation of the FGF-23 concentration with the hematological and biochemical parameters. The coefficient of variation was below 15% for both the intra- and interassay precision, indicating good reproducibility. The reference interval ranged between 95.8 (90% confidence interval: 44.6; 139.2) and 695.1 pg/mL (598.7; 799.1) based on 136 clinically healthy dogs, classified as such according to the information of treating veterinarians as well as the unremarkable results of hematology and biochemistry. The FGF-23 concentration differed significantly between dogs aged <9 and ≥9 years (p = 0.045). Four groups of 10 dogs each were retrospectively formed based on the creatinine concentration classification according to the IRIS staging. Correlation was the strongest for the renal parameters. Statistically significant differences in the FGF-23 concentration were demonstrated between the study groups I and III (p < 0.001), I and IV (p < 0.001), and II and IV (p = 0.005). There was a trend for a rising FGF-23 concentration in older dogs. Due to the wide reference interval, diagnostic cut-offs and/or subject-based FGF-23 reference values in each dog are needed for monitoring and clinical interpretation.
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Affiliation(s)
- Sandra Lapsina
- LABOKLIN GmbH and Co. KG, Steubenstraße 4, 97688 Bad Kissingen, Germany; (S.L.)
| | - Nicole Nagler
- LABOKLIN GmbH and Co. KG, Steubenstraße 4, 97688 Bad Kissingen, Germany; (S.L.)
| | - Simon Franz Müller
- LABOKLIN GmbH and Co. KG, Steubenstraße 4, 97688 Bad Kissingen, Germany; (S.L.)
| | - Annette Holtdirk
- Dr. MED. Kottmann—Clinical Research Organization, Beverstraße 64, 59077 Hamm, Germany
| | - Tanja Kottmann
- Dr. MED. Kottmann—Clinical Research Organization, Beverstraße 64, 59077 Hamm, Germany
| | - Elisabeth Müller
- LABOKLIN GmbH and Co. KG, Steubenstraße 4, 97688 Bad Kissingen, Germany; (S.L.)
| | - Ingo Schäfer
- LABOKLIN GmbH and Co. KG, Steubenstraße 4, 97688 Bad Kissingen, Germany; (S.L.)
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2
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Regulation of FGF23 production and phosphate metabolism by bone-kidney interactions. Nat Rev Nephrol 2023; 19:185-193. [PMID: 36624273 DOI: 10.1038/s41581-022-00665-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/30/2022] [Indexed: 01/11/2023]
Abstract
The bone-derived hormone fibroblast growth factor 23 (FGF23) functions in concert with parathyroid hormone (PTH) and the active vitamin D metabolite, 1,25(OH)2 vitamin D (1,25D), to control phosphate and calcium homeostasis. A rise in circulating levels of phosphate and 1,25D leads to FGF23 production in bone. Circulating FGF23 acts on the kidney by binding to FGF receptors and the co-receptor α-Klotho to promote phosphaturia and reduce circulating 1,25D levels. Various other biomolecules that are produced by the kidney, including lipocalin-2, glycerol 3-phosphate, 1-acyl lysophosphatidic acid and erythropoietin, are involved in the regulation of mineral metabolism via effects on FGF23 synthesis in bone. Understanding of the molecular mechanisms that control FGF23 synthesis in the bone and its bioactivity in the kidney has led to the identification of potential targets for novel interventions. Emerging approaches to target aberrant phosphate metabolism include small molecule inhibitors that directly bind FGF23 and prevent its interactions with FGF receptors and α-Klotho, FGF23 peptide fragments that act as competitive inhibitors of intact FGF23 and small molecule inhibitors of kidney sodium-phosphate cotransporters.
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Brescia V, Fontana A, Lovero R, Capobianco C, Marsico SV, De Chirico T, Pinto C, Varraso L, Cazzolla AP, Di Serio F. Determination of iFGF23 Upper Reference Limits (URL) in healthy pediatric population, for its better correct use. Front Endocrinol (Lausanne) 2022; 13:1018523. [PMID: 36440231 PMCID: PMC9681906 DOI: 10.3389/fendo.2022.1018523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Accepted: 10/12/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The measurement of Fibroblast growth factor 23 (FGF23) may be useful in the diagnosis and management of abnormal phosphate metabolism in both patients with preserved renal function or with chronic kidney disease (CKD). FGF-23 tests differ considerably by molecule assayed (iFGF23 or cFGF23), analytical performance and reference ranges. We establish iFGF23 Upper Reference Limits (URL) in apparently healthy pediatric individuals using automated immunochemiluminescent assay. METHODS We measured the levels of plasma iFGF23 from 115 samples from apparently healthy pediatric subjects [59 (51.3%) individuals were male; median age 10 years (range 1-18)] included in an observational study conducted at Policlinico University Hospital of Bari. The method used for the iFGF23 assay was immunochemiluminescent sandwich assay developed by DiaSorin on the Liaison XL platform. Statistical calculation of 95% reference interval, right-sided (CLSI C28-A3) and verification of age and sex covariables was performed for the calculation of the URL. RESULTS The URL concentration of iFGF23 was 61.21 pg/mL (58.63 to 63.71, 90% CI). No significant differences were found between the median concentrations of iFGF23 differentiated by sex and age. CONCLUSIONS The dosage of iFGF23 is important both for the differential diagnosis of the various forms of rickets, and for the subsequent monitoring of the effectiveness of drug treatment. We have established the URL for the iFGF23 Liaison test in apparently healthy pediatric subjects. The availability of iFGF23 pediatric reference values will allow a better clinical use of the test.
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Affiliation(s)
- Vincenzo Brescia
- Clinical Pathology Unit, Azienda Ospedaliero-Universitaria (AOU) Policlinico Consorziale di Bari - Ospedale Giovanni XXIII, Bari, Italy
| | - Antonietta Fontana
- Clinical Pathology Unit, Azienda Ospedaliero-Universitaria (AOU) Policlinico Consorziale di Bari - Ospedale Giovanni XXIII, Bari, Italy
| | - Roberto Lovero
- Clinical Pathology Unit, Azienda Ospedaliero-Universitaria (AOU) Policlinico Consorziale di Bari - Ospedale Giovanni XXIII, Bari, Italy
- *Correspondence: Roberto Lovero,
| | - Carmela Capobianco
- Clinical Pathology Unit, Azienda Ospedaliero-Universitaria (AOU) Policlinico Consorziale di Bari - Ospedale Giovanni XXIII, Bari, Italy
| | - Stella Vita Marsico
- Clinical Pathology Unit, Azienda Ospedaliero-Universitaria (AOU) Policlinico Consorziale di Bari - Ospedale Giovanni XXIII, Bari, Italy
| | - Tiziana De Chirico
- Clinical Pathology Unit, Azienda Ospedaliero-Universitaria (AOU) Policlinico Consorziale di Bari - Ospedale Giovanni XXIII, Bari, Italy
| | - Carla Pinto
- Clinical Pathology Unit, Azienda Ospedaliero-Universitaria (AOU) Policlinico Consorziale di Bari - Ospedale Giovanni XXIII, Bari, Italy
| | - Lucia Varraso
- Clinical Pathology Unit, Azienda Ospedaliero-Universitaria (AOU) Policlinico Consorziale di Bari - Ospedale Giovanni XXIII, Bari, Italy
| | - Angela Pia Cazzolla
- Department of Clinical and Experimental Medicine, Università degli Studi di Foggia, Foggia, Italy
| | - Francesca Di Serio
- Clinical Pathology Unit, Azienda Ospedaliero-Universitaria (AOU) Policlinico Consorziale di Bari - Ospedale Giovanni XXIII, Bari, Italy
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Haffner D, Leifheit-Nestler M, Grund A, Schnabel D. Rickets guidance: part I-diagnostic workup. Pediatr Nephrol 2022; 37:2013-2036. [PMID: 34910242 PMCID: PMC9307538 DOI: 10.1007/s00467-021-05328-w] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 09/30/2021] [Accepted: 10/01/2021] [Indexed: 01/22/2023]
Abstract
Rickets is a disease of the growing child arising from alterations in calcium and phosphate homeostasis resulting in impaired apoptosis of hypertrophic chondrocytes in the growth plate. Its symptoms depend on the patients' age, duration of disease, and underlying disorder. Common features include thickened wrists and ankles due to widened metaphyses, growth failure, bone pain, muscle weakness, waddling gait, and leg bowing. Affected infants often show delayed closure of the fontanelles, frontal bossing, and craniotabes. The diagnosis of rickets is based on the presence of these typical clinical symptoms and radiological findings on X-rays of the wrist or knee, showing metaphyseal fraying and widening of growth plates, in conjunction with elevated serum levels of alkaline phosphatase. Nutritional rickets due to vitamin D deficiency and/or dietary calcium deficiency is the most common cause of rickets. Currently, more than 20 acquired or hereditary causes of rickets are known. The latter are due to mutations in genes involved in vitamin D metabolism or action, renal phosphate reabsorption, or synthesis, or degradation of the phosphaturic hormone fibroblast growth factor 23 (FGF23). There is a substantial overlap in the clinical features between the various entities, requiring a thorough workup using biochemical analyses and, if necessary, genetic tests. Part I of this review focuses on the etiology, pathophysiology and clinical findings of rickets followed by the presentation of a diagnostic approach for correct diagnosis. Part II focuses on the management of rickets, including new therapeutic approaches based on recent clinical practice guidelines.
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Affiliation(s)
- Dieter Haffner
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany. .,Hannover Medical School, Pediatric Research Center, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
| | - Maren Leifheit-Nestler
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany ,Hannover Medical School, Pediatric Research Center, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Andrea Grund
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany ,Hannover Medical School, Pediatric Research Center, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Dirk Schnabel
- Center for Chronically Sick Children, Pediatric Endocrinology, University Medicine, Charitè Berlin, Germany
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5
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Stanczyk M, Chrul S, Wyka K, Tkaczyk M. Serum intact fibroblast growth factor 23 in healthy paediatric population. Open Med (Wars) 2021; 16:1022-1027. [PMID: 34258392 PMCID: PMC8262519 DOI: 10.1515/med-2021-0288] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 03/28/2021] [Accepted: 04/20/2021] [Indexed: 11/25/2022] Open
Abstract
Introduction It is believed that fibroblast growth factor 23 (FGF23) can become an early biomarker of chronic kidney disease progression. Data on FGF23 age dependency are inconsistent. We present the results of the cross-sectional study concerning FGF23 levels in healthy Polish children. Material and methods This study was conducted in 121 children aged 0–18 years. Kidney function and intact FGF23 levels in serum were assessed. Differences between age groups and according to gender were analysed. Results The difference in FGF23 between age groups and according to gender was statistically insignificant. In the youngest and the oldest group, a trend to higher FGF23 levels was observed. FGF23 level in girls tended to be higher than boys, apart from the age group between 1 and 4 years. There was a negative correlation between eGFR and FGF23 (r = −0.26, p < 0.05) – strong in girls (r = −0.38, p < 0.05), but not in boys. In each age group, we found no significant correlation between eGFR and FGF23. Conclusions Our study supports the evidence that the FGF23 level in paediatric population is not age or sex dependent. The results can serve as a reference point under clinical conditions and for other studies on the topic.
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Affiliation(s)
- Malgorzata Stanczyk
- Department of Pediatrics, Immunology and Nephrology, Polish Mother's Memorial Hospital Research Institute, Rzgowska 281/289, Lodz 93-338, Poland.,Department of Pediatrics, Preventive Cardiology and Immunology of Developmental Age, Medical University of Lodz, Poland
| | - Slawomir Chrul
- Department of Pediatrics, Immunology and Nephrology, Polish Mother's Memorial Hospital Research Institute, Lodz 93-338, Poland
| | - Krystyna Wyka
- Department of Pediatrics, Oncology and Hematology, Medical University of Lodz, Lodz, Poland
| | - Marcin Tkaczyk
- Department of Pediatrics, Immunology and Nephrology, Polish Mother's Memorial Hospital Research Institute, Lodz 93-338, Poland.,Department of Pediatrics, Preventive Cardiology and Immunology of Developmental Age, Medical University of Lodz, Poland
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Baraghithy S, Soae Y, Assaf D, Hinden L, Udi S, Drori A, Gabet Y, Tam J. Renal Proximal Tubule Cell Cannabinoid-1 Receptor Regulates Bone Remodeling and Mass via a Kidney-to-Bone Axis. Cells 2021; 10:414. [PMID: 33671138 PMCID: PMC7922053 DOI: 10.3390/cells10020414] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 02/07/2021] [Accepted: 02/13/2021] [Indexed: 12/20/2022] Open
Abstract
The renal proximal tubule cells (RPTCs), well-known for maintaining glucose and mineral homeostasis, play a critical role in the regulation of kidney function and bone remodeling. Deterioration in RPTC function may therefore lead to the development of diabetic kidney disease (DKD) and osteoporosis. Previously, we have shown that the cannabinoid-1 receptor (CB1R) modulates both kidney function as well as bone remodeling and mass via its direct role in RPTCs and bone cells, respectively. Here we employed genetic and pharmacological approaches that target CB1R, and found that its specific nullification in RPTCs preserves bone mass and remodeling both under normo- and hyper-glycemic conditions, and that its chronic blockade prevents the development of diabetes-induced bone loss. These protective effects of negatively targeting CB1R specifically in RPTCs were associated with its ability to modulate erythropoietin (EPO) synthesis, a hormone known to affect bone mass and remodeling. Our findings highlight a novel molecular mechanism by which CB1R in RPTCs remotely regulates skeletal homeostasis via a kidney-to-bone axis that involves EPO.
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Affiliation(s)
- Saja Baraghithy
- Obesity and Metabolism Laboratory, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel; (S.B.); (Y.S.); (D.A.); (L.H.); (S.U.); (A.D.)
| | - Yael Soae
- Obesity and Metabolism Laboratory, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel; (S.B.); (Y.S.); (D.A.); (L.H.); (S.U.); (A.D.)
| | - Dekel Assaf
- Obesity and Metabolism Laboratory, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel; (S.B.); (Y.S.); (D.A.); (L.H.); (S.U.); (A.D.)
| | - Liad Hinden
- Obesity and Metabolism Laboratory, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel; (S.B.); (Y.S.); (D.A.); (L.H.); (S.U.); (A.D.)
| | - Shiran Udi
- Obesity and Metabolism Laboratory, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel; (S.B.); (Y.S.); (D.A.); (L.H.); (S.U.); (A.D.)
| | - Adi Drori
- Obesity and Metabolism Laboratory, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel; (S.B.); (Y.S.); (D.A.); (L.H.); (S.U.); (A.D.)
| | - Yankel Gabet
- Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv 69978, Israel;
| | - Joseph Tam
- Obesity and Metabolism Laboratory, The Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel; (S.B.); (Y.S.); (D.A.); (L.H.); (S.U.); (A.D.)
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Marcucci G, Brandi ML. Congenital Conditions of Hypophosphatemia Expressed in Adults. Calcif Tissue Int 2021; 108:91-103. [PMID: 32409880 DOI: 10.1007/s00223-020-00695-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 04/15/2020] [Indexed: 01/05/2023]
Abstract
The main congenital conditions of hypophosphatemia expressed in adulthood include several forms of hereditary hypophosphatemic rickets and a congenital disorder of vitamin D metabolism characterized by osteomalacia and hypophosphatemia in adult patients. Hypophosphatemia in adults is defined as serum phosphate concentration < 0.80 mmol/L. The principal regulators of phosphate homeostasis, as is well known, are parathyroid hormone (PTH), activated vitamin D, and Fibroblast Growth Factor 23 (FGF23). Differential diagnosis of hypophosphatemia is based on the evaluation of mechanisms leading to this alteration, such as high PTH activity, inadequate phosphate absorption from the gut, or renal phosphate wasting, either due to primary tubular defects or high FGF23 levels. The most common inherited form associated to hypophosphatemia is X-linked hypophosphatemic rickets (XLH), caused by PHEX gene mutations with enhanced secretion of the FGF23. Until now, the management of hypophosphatemia in adulthood has been poorly investigated. It is widely debated whether adult patients benefit from the conventional treatments normally used for pediatric patients. The new treatment for XLH with burosumab, a recombinant human IgG1 monoclonal antibody that binds to FGF23, blocking its activity, may change the pharmacological management of adult subjects with hypophosphatemia associated to FGF23-dependent mechanisms.
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Affiliation(s)
- Gemma Marcucci
- Bone Metabolic Diseases Unit, Department of Biomedical, Experimental and Clinical Sciences, University of Florence, AOU Careggi, Florence, Italy
| | - Maria Luisa Brandi
- Bone Metabolic Diseases Unit, Department of Biomedical, Experimental and Clinical Sciences, University of Florence, AOU Careggi, Florence, Italy.
- Head Bone Metabolic Diseases Unit, Department of Biomedical, Experimental and Clinical Sciences, University of Florence, Largo Palagi 1, 50139, Florence, Italy.
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Song S, Chang Y, Wang D, Jiang T, Feng J, Lin A. Chronic traffic noise increases food intake and alters gene expression associated with metabolism and disease in bats. J Appl Ecol 2020. [DOI: 10.1111/1365-2664.13710] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Shengjing Song
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization Northeast Normal University Changchun China
- Key Laboratory for Vegetation Ecology Ministry of Education Northeast Normal University Changchun China
| | - Yang Chang
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization Northeast Normal University Changchun China
| | - Daiping Wang
- Department of Behavioural Ecology and Evolutionary Genetics Max Planck Institute for Ornithology Seewiesen Germany
| | - Tinglei Jiang
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization Northeast Normal University Changchun China
| | - Jiang Feng
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization Northeast Normal University Changchun China
- Key Laboratory for Vegetation Ecology Ministry of Education Northeast Normal University Changchun China
- College of Life Science Jilin Agricultural University Changchun China
| | - Aiqing Lin
- Jilin Provincial Key Laboratory of Animal Resource Conservation and Utilization Northeast Normal University Changchun China
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9
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Research Models for Studying Vascular Calcification. Int J Mol Sci 2020; 21:ijms21062204. [PMID: 32210002 PMCID: PMC7139511 DOI: 10.3390/ijms21062204] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 03/17/2020] [Accepted: 03/18/2020] [Indexed: 12/14/2022] Open
Abstract
Calcification of the vessel wall contributes to high cardiovascular morbidity and mortality. Vascular calcification (VC) is a systemic disease with multifaceted contributing and inhibiting factors in an actively regulated process. The exact underlying mechanisms are not fully elucidated and reliable treatment options are lacking. Due to the complex pathophysiology, various research models exist evaluating different aspects of VC. This review aims to give an overview of the cell and animal models used so far to study the molecular processes of VC. Here, in vitro cell culture models of different origins, ex vivo settings using aortic tissue and various in vivo disease-induced animal models are summarized. They reflect different aspects and depict the (patho)physiologic mechanisms within the VC process.
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Almahmoud MF, Soliman EZ, Bertoni AG, Kestenbaum B, Katz R, Lima JAC, Ouyang P, Miller PE, Michos ED, Herrington DM. Fibroblast Growth Factor-23 and Heart Failure With Reduced Versus Preserved Ejection Fraction: MESA. J Am Heart Assoc 2019; 7:e008334. [PMID: 30371180 PMCID: PMC6222949 DOI: 10.1161/jaha.117.008334] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Background Higher fibroblast growth factor‐23 (FGF‐23) levels are associated with incident heart failure (HF) in MESA (the Multiethnic Study of Atherosclerosis). FGF‐23 is also associated with left ventricular hypertrophy. Whether the FGF‐23 association with HF is similar for heart failure with reduced ejection fraction (HFrEF) and heart failure with preserved ejection fraction (HFpEF) is not well established. Methods and Results We studied 6542 participants (mean age 62±10 years, 53% women, mean estimated glomerular filtration rate of 81±18 mL/min per 73 m2) from MESA who were free of cardiovascular disease at baseline (2000–2002). HF events were ascertained by an adjudication committee for a median follow‐up of 12.1 years. We classified HF events as HFrEF (ejection fraction [EF] <50%) or HFpEF [EF] ≥50%) at the time of diagnosis. Cox proportional hazard regression was used to compute hazard ratios and 95% confidence intervals for the association between baseline serum FGF‐23 and incident HFrEF and HFpEF. A total of 134 events were classified as HFpEF, 151 HFrEF, and 49 unknown EF. Following imputation, 149 were classified as HFpEF, 176 HFrEF, and 291 participants had HF (34 participants had HFpEF then HFrEF). In the fully adjusted model, higher FGF‐23 levels were associated with incident HFpEF but not with HFrEF (hazard ratio 1.29, 95% confidence interval, 1.08–1.54) versus (hazard ratio 1.04, 95% confidence interval, 0.84–1.29) for each 20 pg/mL higher serum FGF‐23 concentration. Conclusions FGF‐23 association with HF is driven by the association with HFpEF but not with HFrEF in a population‐based cohort. Further studies are needed to determine the pathological mechanisms mediating this association.
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Affiliation(s)
- Mohamed Faher Almahmoud
- Department of Internal MedicineSection on CardiologyWake Forest School of MedicineWinston‐SalemNC
| | - Elsayed Z. Soliman
- Department of Internal MedicineSection on CardiologyWake Forest School of MedicineWinston‐SalemNC
| | - Alain G. Bertoni
- Department of Epidemiology and PreventionWake Forest School of MedicineWinston‐SalemNC
| | - Bryan Kestenbaum
- Division of NephrologyDepartment of MedicineKidney Research InstituteUniversity of WashingtonSeattleWA
| | - Ronit Katz
- Division of NephrologyDepartment of MedicineKidney Research InstituteUniversity of WashingtonSeattleWA
| | - João A. C. Lima
- Department of RadiologyJohns Hopkins University School of MedicineBaltimoreMD
- Division of CardiologyJohns Hopkins University School of MedicineBaltimoreMD
| | - Pamela Ouyang
- Division of CardiologyJohns Hopkins University School of MedicineBaltimoreMD
| | - P. Elliott Miller
- Department of Critical Care MedicineNational Institutes of HealthBethesdaMD
| | - Erin D. Michos
- Division of CardiologyJohns Hopkins University School of MedicineBaltimoreMD
| | - David M. Herrington
- Department of Internal MedicineSection on CardiologyWake Forest School of MedicineWinston‐SalemNC
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Tabecka-Lonczynska A, Mytych J, Solek P, Kowalewski MP, Koziorowski M. Seasonal expression of insulin-like growth factor 1 (IGF-1), its receptor IGF-1R and klotho in testis and epididymis of the European bison (Bison bonasus, Linnaeus 1758). Theriogenology 2018; 126:199-205. [PMID: 30579142 DOI: 10.1016/j.theriogenology.2018.12.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 12/04/2018] [Indexed: 12/12/2022]
Abstract
The European bisons are the largest mammals of Europe that are still in danger of extinction. The species conservation is associated with their continuous reproduction, and bisons are characterized by the well-pronounced seasonality of reproductive processes. However, the exact mechanisms regulating their reproduction still remain unknown. Our previous studies indicated the involvement of some of the growth factors in the regulation of male seasonal reproductive activities in bison, showing expression patterns that seemed to be regulated by the length of the daylight. In the present study, using RT-PCR and Western blot approaches, we verified the expression and possible relationship between the insulin-like growth factor (IGF-1), its receptor (IGF-1R), and klotho in testis and epididymis of the European bison in pre- and post-reproductive periods, i.e., in June and in December. The observed expression of IGF-1 and IGF-1R mRNA in testis and epididymis was higher in June than in December. At the same time, klotho mRNA expression in both testis and epididymis did not differ between the analyzed seasons. However, along with the higher levels of IGF-1R protein observed in June, klotho protein levels for the membrane form and for the secrete form were higher in December than in June. Finally, the messenger and protein expression profiles presented herein indicate the importance of both the IGF-system and klotho in reproductive processes in the European bison, implying their involvement in the regulation of seasonal testicular activity in males of this threatened species.
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Affiliation(s)
- Anna Tabecka-Lonczynska
- Department of Animal Physiology and Reproduction, Faculty of Biotechnology, University of Rzeszow, Werynia 502, 36-100, Kolbuszowa, Poland.
| | - Jennifer Mytych
- Department of Animal Physiology and Reproduction, Faculty of Biotechnology, University of Rzeszow, Werynia 502, 36-100, Kolbuszowa, Poland
| | - Przemyslaw Solek
- Department of Animal Physiology and Reproduction, Faculty of Biotechnology, University of Rzeszow, Werynia 502, 36-100, Kolbuszowa, Poland
| | - Mariusz P Kowalewski
- Institute of Veterinary Anatomy, Vetsuisse Faculty, University of Zurich, Zurich, Winterthurerstr. 260, CH-8057, Switzerland
| | - Marek Koziorowski
- Department of Animal Physiology and Reproduction, Faculty of Biotechnology, University of Rzeszow, Werynia 502, 36-100, Kolbuszowa, Poland
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Bob F, Schiller A, Timar R, Lighezan D, Schiller O, Timar B, Bujor CG, Munteanu M, Gadalean F, Mihaescu A, Grosu I, Hategan A, Chisavu L, Pusztai AM, Covic A. Rapid decline of kidney function in diabetic kidney disease is associated with high soluble Klotho levels. Nefrologia 2018; 39:250-257. [PMID: 30396700 DOI: 10.1016/j.nefro.2018.08.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2018] [Revised: 07/14/2018] [Accepted: 08/25/2018] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Klotho is found in two forms: a transmembrane form and a soluble form (s-Klotho). In order to be excreted, s-Klotho, that is too large to be filtered, will probably reach the proximal convoluted tubule by a transcytosis process. The aim of our study was to show the relationship between the levels of s-Klotho and tubular injury in patients with diabetic kidney disease (DKD), using as tubular injury marker the kidney injury molecule-1 (KIM-1). METHODS Our study included 63 DKD patients (stages 1-5, mean eGFR 65.15±32.45ml/min) with a mean age 58.13±12 years. In all patients we determined serum levels of: KIM-1 and s-Klotho using ELISA, urinary albumin/creatinine ratio (UACR) and reduction in the estimated glomerular filtration rate (eGFR) per year. RESULTS We found a strong statistically significant correlation of s-Klotho with the rate of reduction of eGFR/year (r=0.714, p=0.0004) and with the tubular injury marker KIM-1 (r=0.758, p=0.005) and strong correlations of UACR with the rate of reduction of eGFR/year (r=0.53, p<0.01), KIM-1 (r=0.49, p<0.05) and s-Klotho (r=0.52, p<0.01). CONCLUSION Despite previous published data, that shows a decrease of s-Klotho in chronic kidney disease, in our study the rapid annual decline of kidney function but not the level of eGFR was associated with increased s-Klotho. A possible explanation could be a more severe proximal tubule injury that could lead to a reduction of tubular excretion of s-Klotho as suggested by the correlation of s-Klotho levels with the serum levels of KIM-1.
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Affiliation(s)
- Flaviu Bob
- Nephrology Department, University of Medicine and Pharmacy "Victor Babes", Timisoara, Romania
| | - Adalbert Schiller
- Nephrology Department, University of Medicine and Pharmacy "Victor Babes", Timisoara, Romania
| | - Romulus Timar
- Diabetes and Metabolic Diseases Department, University of Medicine and Pharmacy "Victor Babes", Timisoara, Romania.
| | - Daniel Lighezan
- Internal Medicine 1 Department, University of Medicine and Pharmacy "Victor Babes", Timisoara, Romania
| | | | - Bogdan Timar
- Medical Informatics and Biostatistics Department, University of Medicine and Pharmacy "Victor Babes", Timisoara, Romania
| | | | - Mircea Munteanu
- Diabetes and Metabolic Diseases Department, University of Medicine and Pharmacy "Victor Babes", Timisoara, Romania
| | - Florica Gadalean
- Nephrology Department, University of Medicine and Pharmacy "Victor Babes", Timisoara, Romania
| | - Adelina Mihaescu
- Nephrology Department, University of Medicine and Pharmacy "Victor Babes", Timisoara, Romania
| | - Iulia Grosu
- Nephrology Department, University of Medicine and Pharmacy "Victor Babes", Timisoara, Romania
| | - Andreea Hategan
- Diabetes and Metabolic Diseases Department, University of Medicine and Pharmacy "Victor Babes", Timisoara, Romania
| | - Lazar Chisavu
- Nephrology Department, University of Medicine and Pharmacy "Victor Babes", Timisoara, Romania
| | - Agneta-Maria Pusztai
- Anatomy Department, University of Medicine and Pharmacy "Victor Babes", Timisoara, Romania
| | - Adrian Covic
- Nephrology Department, Dialysis and Renal Transplant Center, "Dr. C.I. Parhon" University Hospital, "Grigore T. Popa" University of Medicine and Pharmacy, Iasi, Romania
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13
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Marcucci G, Masi L, Ferrarì S, Haffner D, Javaid MK, Kamenický P, Reginster JY, Rizzoli R, Brandi ML. Phosphate wasting disorders in adults. Osteoporos Int 2018; 29:2369-2387. [PMID: 30014155 DOI: 10.1007/s00198-018-4618-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 06/19/2018] [Indexed: 12/14/2022]
Abstract
A cause of hypophosphatemia is phosphate wasting disorders. Knowledge concerning mechanisms involved in phosphate wasting disorders has greatly increased in the last decade by the identification of phosphatonins, among them FGF-23. FGF-23 is a primarily bone derived factor decreasing renal tubular reabsorption of phosphate and the synthesis of calcitriol. Currently, pharmacological treatment of these disorders offers limited efficacy and is potentially associated to gastrointestinal, renal, and parathyroid complications; therefore, efforts have been directed toward newer pharmacological strategies that target the FGF-23 pathway. This review focuses on phosphate metabolism, its main regulators, and phosphate wasting disorders in adults, highlighting the main issues related to diagnosis and current and new potential treatments.
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Affiliation(s)
- G Marcucci
- Metabolic Bone Diseases Unit, Department of Surgery and Translational Medicine, University of Florence, Florence, Italy
| | - L Masi
- Metabolic Bone Diseases Unit, Department of Surgery and Translational Medicine, University of Florence, Florence, Italy
| | - S Ferrarì
- Division of Bone Diseases, Geneva University Hospitals and Faculty of Medicine, Geneva, Switzerland
| | - D Haffner
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Hannover, Germany
| | - M K Javaid
- Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, UK
| | - P Kamenický
- Service d'Endocrinologie et des Maladies de la Reproduction, Centre de référence des Maladies Rares du métabolisme du calcium et du phosphore, Hopital de Bicêtre - AP-HP, 94275, Le Kremlin-Bicêtre, France
| | - J-Y Reginster
- Department of Public Health, Epidemiology and Health Economics, University of Liège, Liège, Belgium
| | - R Rizzoli
- Division of Bone Diseases, Geneva University Hospitals and Faculty of Medicine, Geneva, Switzerland
| | - M L Brandi
- Metabolic Bone Diseases Unit, Department of Surgery and Translational Medicine, University of Florence, Florence, Italy.
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14
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Dayanand P, Sandhyavenu H, Dayanand S, Martinez J, Rangaswami J. Role of Bisphosphonates in Vascular calcification and Bone Metabolism: A Clinical Summary. Curr Cardiol Rev 2018; 14:192-199. [PMID: 29921207 PMCID: PMC6131409 DOI: 10.2174/1573403x14666180619103258] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Revised: 06/03/2018] [Accepted: 06/05/2018] [Indexed: 01/08/2023] Open
Abstract
Background: Vascular
calcification is known to be a strong risk factor for cardiovascularadverse events and mortality. Atherosclerosis, diabetes, aging,
abnormal bone mineral homeostasisand high uremic milieu such as chronic kidney disease are major
factors that contribute to theprogression of vascular calcification. Several mechanisms such
as the osteoblastic transition of vascularsmooth muscle cells in response to oxidative stress have shed
light on the active nature ofvascular calcification, which was once thought to be a passive
process. The fine interplay of regulatoryfactors such as PTH, vitamin D3, FGF 23 and klotho reflect the
delicate balance between vascularcalcification and bone mineralization. Any disturbance affecting
this equilibrium of the bonemineral-vascular axis results in accelerated vascular calcification. Bisphosphonates share similar mechanism of action as statins,
and hence several studies were undertakenin humans to verify if the benefits proven to be obtained in
animal models extended tohuman models too. This yielded conflicting outcomes which are
outlined in this review. This wasattributed mainly to inadequate sample size and flaws in the
study design. Therefore, this benefitcan only be ascertained if studies addressing this are
undertaken. Conclusion: This review seeks to
highlight the pathophysiologic phenomena implicated in vascular and valvular calcification and summarize the literature
available regarding the use of bisphosphonates in animal and human models. We also discuss novel treatment
approaches for vascular calcification,with emphasis on chronic kidney disease and calciphylaxis.
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Affiliation(s)
- Pradeep Dayanand
- Department of Internal Medicine, University of Miami/JFK Medical Center, Atlantis, FL, United States
| | | | - Sandeep Dayanand
- Department of Cardiology, Einstein Medical Center, Philadelphia, PA, United States
| | - Jasmin Martinez
- Department of Cardiology, Einstein Medical Center, Philadelphia, PA, United States
| | - Janani Rangaswami
- Department of Nephrology, Einstein Medical Center, Sidney Kimmel College of Thomas Jefferson University, Philadelphia, PA, United States
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15
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Li L, Wang SX, Wu HM, Luo DL, Dong GF, Feng Y, Zhang X. Acquired hypophosphatemic osteomalacia is easily misdiagnosed or neglected by rheumatologists: A report of 9 cases. Exp Ther Med 2018; 15:5389-5393. [PMID: 29904418 DOI: 10.3892/etm.2018.6106] [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: 08/02/2016] [Accepted: 05/11/2017] [Indexed: 12/23/2022] Open
Abstract
The aim of the present study was to assist rheumatologists in differentiating hypophosphatemic osteomalacia (HO) from mimic rheumatology diseases. Clinical data was obtained from 9 patients with acquired HO, initially misdiagnosed as mimic rheumatologic diseases. The data were retrospectively analyzed and a literature review was performed. The etiology of the cases was as follows: Adefovir dipivoxil-induced Fanconi syndrome was present in 6 of the cases, 2 were tumors and 1 case was chronic nephropathy. The chief complaint was thoracic or back pain and arthralgia, followed by progressive muscle weakness and dramatic movement limitation. All patients were transferred to 3-6 hospitals for extended periods due to misdiagnosis with conditions such as ankylosing spondylitis, chronic arthritis, lumbar disc disease, osteoporosis and somatoform disorder. Hypophosphatemia was observed in the patients and bone scans revealed diffusely decreased tracer uptake, with multiple hot spots of fractured sites and involved joints. Furthermore, patients' bone density was markedly low compared with the normal range for their age and sex. In the present study, 6 of the patients recovered when adefovir dipivoxil was stopped. In 1 case, hypophosphatemia was ameliorated following tumor resection. The remaining patients, 1 with sub-skull tumor and 1 with chronic kidney disease, had poor prognoses due to incurable diseases. In conclusion, diagnosing HO is challenging for rheumatologists and physicians. Basic examinations of electrolyte balance and bone mineral density should be performed, as should tumor screening and a careful collection of patient medical history and drugs in young patients with unexplained thoracic or back pain and muscle weakness. Removing any secondary etiology, such as drugs may dramatically improve the patients clinical manifestations and result in an improved prognosis.
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Affiliation(s)
- Ling Li
- Department of Rheumatology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510080, P.R. China
| | - Shu-Xia Wang
- Department of Nuclear Medicine, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510080, P.R. China
| | - Hong-Mei Wu
- Department of Pathology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510080, P.R. China
| | - Dong-Lan Luo
- Department of Pathology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510080, P.R. China
| | - Guang-Fu Dong
- Department of Rheumatology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510080, P.R. China
| | - Yuan Feng
- Department of Rheumatology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510080, P.R. China
| | - Xiao Zhang
- Department of Rheumatology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510080, P.R. China
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16
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Maia MLDA, Abreu ALS, Nogueira PCK, Val MLDMD, Carvalhaes JTDA, Andrade MCD. HYPOPHOSPHATEMIC RICKETS: CASE REPORT. ACTA ACUST UNITED AC 2018; 36:242-247. [PMID: 29617471 PMCID: PMC6038795 DOI: 10.1590/1984-0462/;2018;36;2;00009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 05/16/2017] [Indexed: 11/22/2022]
Abstract
OBJECTIVE Early diagnosis and immediate treatment of hypophosphatemic rickets is of utmost importance as it may prevent subsequent sequelae. This report aims at warning pediatricians to consider the presence of the disease. CASE DESCRIPTION Description of the metabolic profile, creatinine clearance, nutritional status, weight and body structure of a patient who presented the clinical-laboratorial characteristics of hypophosphatemic rickets and was followed in an outpatient clinic for tubulopathies over the period of 12 months. The patient had been bedridden for some time, was dependent on mechanical ventilation and presented an altered metabolic bone condition. Treatment was phosphate (initial: 65 mg/kg/day and final: 24,2 mg/kg/day), calcium (initial: 127 mg/kg/day, final: 48,4 mg/kg/day) and calcitriol (initial: 0.06 mcg/kg/day, final: 0.03 mcg/kg/day). The patient improved, evolving into spontaneous breathing and walking unaided. Laboratory results: calcium (mg/dL) initial 7.1, final 10.1; phosphate (mg/dL) initial 1.7 final 3.2; magnesium (mg/dL) initial 1.5 final 2.1, parathyroid hormone (pg/l) initial 85.8, final 52.7, alkaline phosphatase (UI/l) initial 12660, final 938; there was also improvement in weight/structural development (Z score: H/A initial: -6.05, final -3.64; W/A: initial -2.92, final -1.57) with presence of transitory gallstones. Creatinine clearance (mL/min/1.73m2bsa) was constant. The medication improved his laboratory results and nutritional status, but the patient did not return for two years for follow-up and, during this period, his condition has noticeably deteriorated. COMMENTS Early diagnosis and follow-up are essential in dealing with this pathology.
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17
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Alimohammadi N, Javadian P, Malekpour A, Tahmasebian S. Association of serum fibroblast growth factor 23 with calcium metabolism in patients with end-stage renal disease undergoing hemodialysis. J Nephropathol 2017. [DOI: 10.15171/jnp.2017.57] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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18
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Harjes LM, Parker VJ, Dembek K, Young GS, Giovaninni LH, Kogika MM, Chew DJ, Toribio RE. Fibroblast Growth Factor-23 Concentration in Dogs with Chronic Kidney Disease. J Vet Intern Med 2017; 31:784-790. [PMID: 28419560 PMCID: PMC5435078 DOI: 10.1111/jvim.14707] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 12/29/2016] [Accepted: 02/27/2017] [Indexed: 02/06/2023] Open
Abstract
Background Chronic kidney disease (CKD) is associated with hyperphosphatemia, decreased vitamin D metabolite concentrations, and hyperparathyroidism. This syndrome is known as CKD‐mineral bone disorder (CKD‐MBD). Recently, it has been shown that an increase in fibroblast growth factor‐23 (FGF‐23) concentration is an early biomarker of CKD in people. It is an independent risk factor for both progression of renal disease and survival time in humans and cats with CKD. Information about FGF‐23 in healthy dogs and those with CKD is lacking. Objectives To measure FGF‐23 concentration in dogs with different stages of CKD and determine its association with factors involved in CKD‐MBD, including serum phosphorus and parathyroid hormone (PTH) concentrations. A secondary aim was to validate an ELISA for measurement of plasma FGF‐23 concentration in dogs. Animals Thirty‐two client‐owned dogs with naturally occurring CKD and 10 healthy control dogs. Methods Prospective cross‐sectional study. An FGF‐23 ELISA was used to measure plasma FGF‐23 concentration in dogs and their association with serum creatinine, phosphorus, calcium, and PTH concentrations. Results Plasma FGF‐23 concentrations increased with severity of CKD and were significantly different between IRIS stages 1 and 2 versus stages 3 and 4 (P < .0001). Increases in FGF‐23 concentrations were more frequent than hyperparathyroidism or hyperphosphatemia in this cohort. Serum creatinine and phosphorus concentrations were the strongest independent predictors of FGF‐23 concentration. Conclusions and clinical importance Plasma FGF‐23 concentrations increase in dogs with CKD as disease progresses. Plasma FGF‐23 concentrations appear to be useful for further study of the pathophysiology of CKD‐MBD in dogs.
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Affiliation(s)
- L M Harjes
- Veterinary Clinical Sciences, The Ohio State University, Columbus, OH
| | - V J Parker
- Veterinary Clinical Sciences, The Ohio State University, Columbus, OH
| | - K Dembek
- Veterinary Clinical Sciences, The Ohio State University, Columbus, OH
| | - G S Young
- Center for Biostatistics, The Ohio State University, Columbus, OH
| | - L H Giovaninni
- School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, SP, Brazil
| | - M M Kogika
- School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, SP, Brazil
| | - D J Chew
- Veterinary Clinical Sciences, The Ohio State University, Columbus, OH
| | - R E Toribio
- Veterinary Clinical Sciences, The Ohio State University, Columbus, OH
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19
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Lu X, Hu MC. Klotho/FGF23 Axis in Chronic Kidney Disease and Cardiovascular Disease. KIDNEY DISEASES 2016; 3:15-23. [PMID: 28785560 DOI: 10.1159/000452880] [Citation(s) in RCA: 123] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Accepted: 10/26/2016] [Indexed: 12/26/2022]
Abstract
BACKGROUND Membrane αKlotho (hereinafter called Klotho) is highly expressed in the kidney and functions as a coreceptor of FGF receptors (FGFRs) to activate specific fibroblast growth factor 23 (FGF23) signal pathway. FGF23 is produced in bones and participates in the maintenance of mineral homeostasis. The extracellular domain of transmembrane Klotho can be cleaved by secretases and released into the circulation as soluble Klotho. Soluble Klotho does not only weakly activate FGFRs to transduce the FGF23 signaling pathway, but also functions as an enzyme and hormonal substance to play a variety of biological functions. FGF23 exerts its biological effects through activation of FGFRs in a Klotho-dependent manner. However, extremely high FGF23 can exert its pathological action in a Klotho-independent manner. SUMMARY The decline in serum and urinary Klotho followed by a rise in serum FGF23 at an early stage of chronic kidney disease (CKD) functions as an early biomarker for kidney dysfunction and can also serve as a predictor for risk of cardiovascular disease (CVD) and mortality in both CKD patients and the general population. Moreover, Klotho deficiency is a pathogenic factor for CKD progression and CVD. FGF23 may also contribute to CVD. Prevention of Klotho decline, reactivation of endogenous Klotho production, or supplementation of exogenous Klotho attenuate renal fibrosis, retard CKD progression, improve mineral metabolism, ameliorate cardiomyopathy, and alleviate vascular calcification in CKD. However, the poor CVD outcome after depletion of FGF23 with FGF23 antibody stimulates the generation of a more specific inhibitor of FGF23 for CKD treatment. KEY MESSAGE Klotho/FGF23 may not only be diagnostic and/or prognostic biomarkers for CKD and CVD, but are also pathogenic contributors to CKD progression and CVD development. The Klotho/FGF23 axis should be a novel target for renal clinics.
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Affiliation(s)
- Xiang Lu
- Department of Geriatrics, Sir Run Run Hospital, Nanjing Medical University, Nanjing, PR China
| | - Ming Chang Hu
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA.,Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA.,Department of Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX, USA
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20
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Abstract
Alpha-Klotho (αKlotho) protein is encoded by the gene, Klotho, and functions as a coreceptor for endocrine fibroblast growth factor-23. The extracellular domain of αKlotho is cleaved by secretases and released into the circulation where it is called soluble αKlotho. Soluble αKlotho in the circulation starts to decline in chronic kidney disease (CKD) stage 2 and urinary αKlotho in even earlier CKD stage 1. Therefore soluble αKlotho is an early and sensitive marker of decline in kidney function. Preclinical data from numerous animal experiments support αKlotho deficiency as a pathogenic factor for CKD progression and extrarenal CKD complications including cardiac and vascular disease, hyperparathyroidism, and disturbed mineral metabolism. αKlotho deficiency induces cell senescence and renders cells susceptible to apoptosis induced by a variety of cellular insults including oxidative stress. αKlotho deficiency also leads to defective autophagy and angiogenesis and promotes fibrosis in the kidney and heart. Most importantly, prevention of αKlotho decline, upregulation of endogenous αKlotho production, or direct supplementation of soluble αKlotho are all associated with attenuation of renal fibrosis, retardation of CKD progression, improvement of mineral metabolism, amelioration of cardiac function and morphometry, and alleviation of vascular calcification in CKD. Therefore in rodents, αKlotho is not only a diagnostic and prognostic marker for CKD but the enhancement of endogenous or supplement of exogenous αKlotho are promising therapeutic strategies to prevent, retard, and decrease the comorbidity burden of CKD.
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Affiliation(s)
- J A Neyra
- University of Texas Southwestern Medical Center, Dallas, TX, United States; Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - M C Hu
- University of Texas Southwestern Medical Center, Dallas, TX, United States; Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX, United States.
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21
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Abstract
The α-Klotho mouse is an animal model that prematurely shows phenotypes resembling human aging, such as osteoporosis, arteriosclerosis, pulmonary emphysema, and kidney damage. Interestingly, these abnormalities are triggered by a deficiency of a single protein, α-Klotho. The kidney is an organ that highly expresses α-Klotho, suggesting that α-Klotho is important for kidney function. Recent studies suggest that α-Klotho is associated with phosphate, vitamin D, and calcium homeostasis. The calcium imbalance in α-Klotho mice may induce calpain overactivation, leading to cell death and tissue destruction. α-Klotho is predicted to have glycosidase activity, capable of modifying the N-glycans of channels and transporters and regulating transmembrane movement of several ions, including calcium. Interestingly, N-glycan changes are observed in the kidney of α-Klotho mice and normal aged mice in association with decreased α-Klotho levels. These results imply that glycobiology and α-Klotho function are interesting targets for future studies.
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22
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Han X, Yang J, Li L, Huang J, King G, Quarles LD. Conditional Deletion of Fgfr1 in the Proximal and Distal Tubule Identifies Distinct Roles in Phosphate and Calcium Transport. PLoS One 2016; 11:e0147845. [PMID: 26839958 PMCID: PMC4739706 DOI: 10.1371/journal.pone.0147845] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 01/08/2016] [Indexed: 01/10/2023] Open
Abstract
A postnatal role of fibroblast growth factor receptor-1 (FGFR1) in the kidney is suggested by its binding to α-Klotho to form an obligate receptor for the hormone fibroblast growth factor-23 (FGF-23). FGFR1 is expressed in both the proximal and distal renal tubular segments, but its tubular specific functions are unclear. In this study, we crossed Fgfr1flox/flox mice with either gamma-glutamyltransferase-Cre (γGT-Cre) or kidney specific-Cre (Ksp-Cre) mice to selectively create proximal tubule (PT) and distal tubule (DT) Fgfr1 conditional knockout mice (designated Fgfr1PT-cKOand Fgfr1DT-cKO, respectively). Fgfr1PT-cKO mice exhibited an increase in sodium-dependent phosphate co-transporter expression, hyperphosphatemia, and refractoriness to the phosphaturic actions of FGF-23, consistent with a direct role of FGFR1 in mediating the proximal tubular phosphate responses to FGF-23. In contrast, Fgfr1DT-cKO mice unexpectedly developed hypercalciuria, secondary elevations of parathyroid hormone (PTH), hypophosphatemia and enhanced urinary phosphate excretion. Fgfr1PT-cKO mice also developed a curly tail/spina bifida-like skeletal phenotype, whereas Fgfr1DT-cKO mice developed renal tubular micro-calcifications and reductions in cortical bone thickness. Thus, FGFR1 has dual functions to directly regulate proximal and distal tubule phosphate and calcium reabsorption, indicating a physiological role of FGFR1 signaling in both phosphate and calcium homeostasis.
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Affiliation(s)
- Xiaobin Han
- Department of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Jiancheng Yang
- Department of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Linqiang Li
- Department of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Jinsong Huang
- Department of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Gwendalyn King
- University of Alabama in Birmingham, Birmingham, Alabama, United States of America
| | - L. Darryl Quarles
- Department of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
- * E-mail:
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23
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Neyra JA, Moe OW, Hu MC. Fibroblast growth factor 23 and acute kidney injury. Pediatr Nephrol 2015; 30:1909-18. [PMID: 25480729 PMCID: PMC4458234 DOI: 10.1007/s00467-014-3006-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 11/03/2014] [Accepted: 11/04/2014] [Indexed: 02/07/2023]
Abstract
Fibroblast growth factor 23 (FGF23), which is produced in bone, participates in the maintenance of phosphate metabolism and can serve as a biomarker for adverse cardiovascular outcomes in patients with chronic kidney disease and end-stage renal disease. Circulating FGF23 rapidly increases after acute kidney injury (AKI), preceding other known markers such as neutrophil gelatinase-associated lipocalin and serum creatinine. The increase in FGF23 in AKI appears to be independent of parathyroid hormone, vitamin D signaling pathways, and dietary phosphate. The potential mechanisms include: (1) increased production of FGF23 in the bone by yet-to-be-identified factors; (2) ectopic production of FGF23 by injured renal tubules; and (3) decreased renal clearance of circulating FGF23. Circulating FGF23 determined by intact FGF23 enzyme-linked immunosorbent assay (ELISA) is a more reliable biomarker of AKI than FGF23 C-terminal ELISA (a mixed readout of C-terminal fragment and intact FGF23). Given that FGF23 can be ectopically expressed in differentiated renal tubules and iron modulates FGF23 metabolism, an effect of iron on FGF23 expression in renal tubules is conceivable but remains to be confirmed. More clinical and experimental studies are required to validate the use of circulating FGF23 as a biomarker for the early identification of AKI and prediction of short- and long-term adverse outcomes post-AKI. More importantly, the biologic effect of increased FGF23 in AKI needs to be defined.
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Affiliation(s)
- Javier A Neyra
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390-885, USA
| | - Orson W Moe
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390-885, USA
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390-885, USA
| | - Ming Chang Hu
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390-885, USA.
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390-885, USA.
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Latifyan SB, Vanhaeverbeek M, Klastersky J. Tumour-associated osteomalacia and hypoglycaemia in a patient with prostate cancer: is Klotho involved? BMJ Case Rep 2014; 2014:bcr-2014-206590. [PMID: 25406200 DOI: 10.1136/bcr-2014-206590] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Tumour-associated osteomalacia is a paraneoplastic syndrome caused by renal phosphate wasting, leading to severe hypophosphataemia. Excess of circulating fibroblast growth factor 23 (FGF23) is the likely cause, acting via the FGF23/α-Klotho coreceptor, a critical regulator of phosphate metabolism. The other possible effects of that complex in humans are still under investigation. We present a case of an 84-year-old Belgian man, presenting prostate cancer with bone metastases. From June 2010 to March 2013, he presented three episodes of disease progression. From January 2012, the patient developed a progressively marked dorsal kyphosis with significant hypophosphataemia. The calculated TRP (tubular reabsorption of phosphate) was decreased and the FGF23 increased. Mid-March 2013, the patient died after a profound unconsciousness due to hypoglycaemia with hypothermia. We hypothesised that the two paraneoplastic manifestations of this patient (tumour-associated osteomalacia and refractory hypoglycaemia) were due to one cause chain with two main nodes-FGF23 and its coreceptor Klotho..
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Affiliation(s)
- Sofiya Bedo Latifyan
- Institut Jules Bordet, Brussels, Belgium Université Libre de Bruxelles, Brussels, Belgium
| | - Michel Vanhaeverbeek
- Université Libre de Bruxelles, Brussels, Belgium Centre Hospitalo-Universitaire de Charleroi, Charleroi, Belgium
| | - Jean Klastersky
- Institut Jules Bordet, Brussels, Belgium Université Libre de Bruxelles, Brussels, Belgium
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Gkentzi D, Efthymiadou A, Kritikou D, Chrysis D. Fibroblast growth factor 23 and Klotho serum levels in healthy children. Bone 2014; 66:8-14. [PMID: 24880094 DOI: 10.1016/j.bone.2014.05.012] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Revised: 05/13/2014] [Accepted: 05/22/2014] [Indexed: 12/18/2022]
Abstract
Data for fibroblast growth factor 23 (FGF23) and particularly for Klotho in healthy children are limited. We aimed to investigate the relationship between FGF23 and Klotho with age and TmP/GFR and to evaluate parameters that might affect FGF23 and Klotho. In 159 healthy children (82 boys) with a mean±SD age of 8.78±3.47years we measured FGF23 (intact FGF23/iFGF23 and C-terminal FGF23/cFGF23) and soluble aKlotho serum levels by ELISA. Mean±SD value for cFGF23, was 51.14±12.79 RU/ml whereas median (range) values for iFGF23 and Klotho were 35 (8.8, 120) pg/ml and 1945 (372, 5866) pg/ml respectively. Neither FGF23 nor Klotho were significantly associated with age. Pubertal children had higher Klotho than prepubertal (p<0.05), and girls had higher levels of cFGF23 (p<0.05) and Klotho (p<0.001) than boys. Serum phosphate and TmP/GFR were positively associated with cFGF23 (p<0.01 and p<0.001), iFGF23 (p<0.05 and p<0.001) and Klotho (p<0.05 and p<0.01). Klotho was positively correlated with IGF-I (p<0.0001) and 1,25 (OH)2 vitamin D (p<0.05). In this study we provide data on cFGF23, iFGF23, and Klotho measured simultaneously in healthy children. The positive association of serum phosphate and TmP/GFR with FGF23 and Klotho suggests that they have a counterregulatory effect on phosphate homeostasis. The strong association of Klotho with IGF-I could indicate a role of Klotho in linear growth through phosphate regulation, but further studies are required.
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Affiliation(s)
- Despoina Gkentzi
- Department of Pediatrics, Medical School, University of Patras, Rio, Greece.
| | - Alexandra Efthymiadou
- Pediatric Endocrine Unit, Department of Pediatrics, Medical School, University of Patras, Rio, Greece
| | - Dimitra Kritikou
- Pediatric Endocrine Unit, Department of Pediatrics, Medical School, University of Patras, Rio, Greece
| | - Dionisios Chrysis
- Pediatric Endocrine Unit, Department of Pediatrics, Medical School, University of Patras, Rio, Greece
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Mutsaers H, Levtchenko E, Martinerie L, Pertijs J, Allegaert K, Devriendt K, Masereeuw R, Monnens L, Lombes M. Switch in FGFR3 and -4 expression profile during human renal development may account for transient hypercalcemia in patients with Sotos syndrome due to 5q35 microdeletions. J Clin Endocrinol Metab 2014; 99:E1361-7. [PMID: 24670087 PMCID: PMC5373678 DOI: 10.1210/jc.2014-1123] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
CONTEXT Sotos syndrome is a rare genetic disorder with a distinct phenotypic spectrum including overgrowth and learning difficulties. Here we describe a new case of Sotos syndrome with a 5q35 microdeletion, affecting the fibroblast growth factor receptor 4 (FGFR4) gene, presenting with infantile hypercalcemia. OBJECTIVE We strove to elucidate the evanescent nature of the observed hypercalcemia by studying the ontogenesis of FGFR3 and FGFR4, which are both associated with fibroblast growth factor (FGF) 23-mediated mineral homeostasis, in the developing human kidney. DESIGN Quantitative RT-PCR and immunohistochemical analyses were used on archival human kidney samples to investigate the expression of the FGFR signaling pathway during renal development. RESULTS We demonstrated that renal gene and protein expression of both FGFRs increased during fetal development between the gestational ages (GAs) of 14-40 weeks. Yet FGFR4 expression increased more rapidly as compared with FGFR3 (slope 0.047 vs 0.0075, P = .0018). Moreover, gene and protein expression of the essential FGFR coreceptor, Klotho, also increased with a significant positive correlation between FGFR and Klotho mRNA expression during renal development. Interestingly, we found that perinatal FGFR4 expression (GA 38-40 wk) was 7-fold higher as compared with FGFR3 (P = .0035), whereas in adult kidney tissues, FGFR4 gene expression level was more than 2-fold lower compared with FGFR3 (P = .0029), thus identifying a molecular developmental switch of FGFR isoforms. CONCLUSION We propose that the heterozygous FGFR4 deletion, as observed in the Sotos syndrome patient, leads to a compromised FGF23 signaling during infancy accounting for transient hypercalcemia. These findings represent a novel and intriguing view on FGF23 mediated calcium homeostasis.
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MESH Headings
- Chromosome Deletion
- Chromosomes, Human, Pair 5/genetics
- Fetus/metabolism
- Fibroblast Growth Factor-23
- Genes, Switch
- Humans
- Hypercalcemia/complications
- Hypercalcemia/genetics
- Infant, Newborn
- Kidney/embryology
- Kidney/metabolism
- Male
- Receptor, Fibroblast Growth Factor, Type 3/genetics
- Receptor, Fibroblast Growth Factor, Type 3/metabolism
- Receptor, Fibroblast Growth Factor, Type 4/genetics
- Receptor, Fibroblast Growth Factor, Type 4/metabolism
- Sotos Syndrome/genetics
- Sotos Syndrome/metabolism
- Transcriptome
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Affiliation(s)
- Henricus Mutsaers
- Récepteurs stéroïdiens : physiopathologie endocrinienne et métabolique
Université Paris-Sud - Paris 11 - IFR93 - Institut National de la Santé et de la Recherche Médicale - U693Faculté de médecine 63, Rue Gabriel Peri 94276 le Kremlin Bîcetre
- Department of Pharmacology and Toxicology
Radboud University Medical Center [Nijmegen] - Nijmegen
| | - Elena Levtchenko
- Department of Pediatrics & Department of Growth and Regeneration
Katholieke Universiteit Leuven - University Hospitals Leuven [Leuven] - Leuven
| | - Laetitia Martinerie
- Récepteurs stéroïdiens : physiopathologie endocrinienne et métabolique
Université Paris-Sud - Paris 11 - IFR93 - Institut National de la Santé et de la Recherche Médicale - U693Faculté de médecine 63, Rue Gabriel Peri 94276 le Kremlin Bîcetre
| | - Jeanne Pertijs
- departement of Pharmacology, Radboud University
Radboud University Medical Center [Nijmegen] -
| | - Karel Allegaert
- Department of Pediatrics & Department of Growth and Regeneration
Katholieke Universiteit Leuven - University Hospitals Leuven [Leuven] - Leuven
| | - Koenraad Devriendt
- Centre for Human Genetics
Katholieke Universiteit Leuven - University Hospitals Leuven [Leuven] - Leuven
| | - Rosalinde Masereeuw
- departement of Pharmacology, Radboud University
Radboud University Medical Center [Nijmegen] -
| | - Leo Monnens
- Department of Physiology
Radboud University Medical Center [Nijmegen] - Nijmegen
| | - Marc Lombes
- Récepteurs stéroïdiens : physiopathologie endocrinienne et métabolique
Université Paris-Sud - Paris 11 - IFR93 - Institut National de la Santé et de la Recherche Médicale - U693Faculté de médecine 63, Rue Gabriel Peri 94276 le Kremlin Bîcetre
- PremUp Foundation
Université Paris-Sud - Paris 11 - Université Pierre et Marie Curie - Paris 6 - Université Paris Diderot - Paris 7 - CHI Créteil - Université Paris Descartes - Paris 5 - Sorbonne Universités - Institut National de la Santé et de la Recherche Médicale - Institut de Recherche pour le Développement (IRD) - Faculté de Pharmacie - 4 Avenue de l'Observatoire 75270 Paris Cedex 06
- * Correspondence should be addressed to Marc Lombes
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Penido MGMG, Alon US. Hypophosphatemic rickets due to perturbations in renal tubular function. Pediatr Nephrol 2014; 29:361-73. [PMID: 23636577 DOI: 10.1007/s00467-013-2466-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2012] [Revised: 03/03/2013] [Accepted: 03/04/2013] [Indexed: 12/13/2022]
Abstract
The common denominator for all types of rickets is hypophosphatemia, leading to inadequate supply of the mineral to the growing bone. Hypophosphatemia can result from insufficient uptake of the mineral from the gut or its disproportionate losses in the kidney, the latter being caused by either tubular abnormalities per se or the effect on the tubule of circulating factors like fibroblast growth factor-23 and parathyroid hormone (PTH). High serum levels of the latter result in most cases from abnormalities in vitamin D metabolism which lead to decreased calcium absorption in the gut and hypocalcemia, triggering PTH secretion. Rickets is a disorder of the growth plate and hence pediatric by definition. However, it is important to recognize that the effect of hypophosphatemia on other parts of the skeleton results in osteomalacia in both children and adults. This review addresses the etiology, pathophysiologic mechanisms, clinical manifestations and treatment of entities associated with hypophosphatemic rickets due to perturbations in renal tubular function.
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Affiliation(s)
- Maria Goretti M G Penido
- Pediatric Nephrology Unit, Clinics Hospital, School of Medicine, Federal University of Minas Gerais, Av. Professor Alfredo Balena, 190, CEP, 30130100, Belo Horizonte, MG, Brazil,
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Gattineni J, Alphonse P, Zhang Q, Mathews N, Bates CM, Baum M. Regulation of renal phosphate transport by FGF23 is mediated by FGFR1 and FGFR4. Am J Physiol Renal Physiol 2014; 306:F351-8. [PMID: 24259513 PMCID: PMC3920047 DOI: 10.1152/ajprenal.00232.2013] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Accepted: 11/19/2013] [Indexed: 12/30/2022] Open
Abstract
Fibroblast growth factor 23 (FGF23) is a bone-derived hormone that acts on the proximal tubule to decrease phosphate reabsorption and serum levels of 1,25-dihydroxyvitamin D₃ [1,25(OH)₂ Vitamin D₃]. Abnormal FGF23 metabolism has been implicated in several debilitating hypophosphatemic and hyperphosphatemic disorders. The renal receptors responsible for the phosphaturic actions of FGF23 have not been elucidated. There are four fibroblast growth factor receptors (FGFR); 1-4 with "b" and "c" isoforms for receptors 1, 2, and 3. FGFR1, 3, and 4 are expressed in the mouse proximal tubule, and deletion of any one receptor did not affect serum phosphate levels, suggesting that more than one receptor is involved in mediating the phosphaturic actions of FGF23. To determine the receptors responsible for the phosphaturic actions of FGF23, we studied Fgfr1 (kidney conditional) and Fgfr4 (global) double mutant mice (Fgfr1⁻/⁻/Fgfr4⁻/⁻). Fgfr1⁻/⁻/Fgfr4⁻/⁻ mice have higher FGF23 levels than their wild-type counterparts (108.1 ± 7.3 vs. 4,953.6 ± 675.0 pg/ml; P < 0.001). Despite the elevated FGF23 levels, Fgfr1⁻/⁻/Fgfr4⁻/⁻ mice have elevated serum phosphorus levels, increased brush-border membrane vesicle (BBMV) phosphate transport, and increased Na-P(i) cotransporter 2c (NaPi-2c) protein expression compared with wild-type mice. These data are consistent with FGFR1 and FGFR4 being the critical receptors for the phosphaturic actions of FGF23.
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Affiliation(s)
- Jyothsna Gattineni
- Dept. of Pediatrics, UT Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX.
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de Brito Galvao JF, Nagode LA, Schenck PA, Chew DJ. Calcitriol, calcidiol, parathyroid hormone, and fibroblast growth factor-23 interactions in chronic kidney disease. J Vet Emerg Crit Care (San Antonio) 2013; 23:134-62. [PMID: 23566108 PMCID: PMC3677418 DOI: 10.1111/vec.12036] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2012] [Accepted: 02/05/2013] [Indexed: 12/13/2022]
Abstract
Objective To review the inter-relationships between calcium, phosphorus, parathyroid hormone (PTH), parent and activated vitamin D metabolites (vitamin D, 25(OH)-vitamin D, 1,25(OH)2-vitamin D, 24,25(OH)2-vitamin D), and fibroblast growth factor-23 (FGF-23) during chronic kidney disease (CKD) in dogs and cats. Data Sources Human and veterinary literature. Human Data Synthesis Beneficial effects of calcitriol treatment during CKD have traditionally been attributed to regulation of PTH but new perspectives emphasize direct renoprotective actions independent of PTH and calcium. It is now apparent that calcitriol exerts an important effect on renal tubular reclamation of filtered 25(OH)-vitamin D, which may be important in maintaining adequate circulating 25(OH)-vitamin D. This in turn may be vital for important pleiotropic actions in peripheral tissues through autocrine/paracrine mechanisms that impact the health of those local tissues. Veterinary Data Synthesis Limited information is available reporting the benefit of calcitriol treatment in dogs and cats with CKD. Conclusions A survival benefit has been shown for dogs with CKD treated with calcitriol compared to placebo. The concentrations of circulating 25(OH)-vitamin D have recently been shown to be low in people and dogs with CKD and are related to survival in people with CKD. Combination therapy for people with CKD using both parental and activated vitamin D compounds is common in human nephrology and there is a developing emphasis using combination treatment with activated vitamin D and renin-angiotensin-aldosterone-system (RAAS) inhibitors.
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Dërmaku-Sopjani M, Kolgeci S, Abazi S, Sopjani M. Significance of the anti-aging protein Klotho. Mol Membr Biol 2013; 30:369-85. [PMID: 24124751 DOI: 10.3109/09687688.2013.837518] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The Klotho gene was identified as an 'aging suppressor' in mice. Overexpression of the Klotho gene extends lifespan and defective Klotho results in rapid aging and early death. Both the membrane and secreted forms of Klotho have biological activity that include regulatory effects on general metabolism and a more specific effect on mineral metabolism that correlates with its effect on aging. Klotho serves as a co-receptor for fibroblast growth factor (FGF), but it also functions as a humoral factor that regulates cell survival and proliferation, vitamin D metabolism, and calcium and phosphate homeostasis and may serve as a potential tumor suppressor. Moreover, Klotho protects against several pathogenic processes in a FGF23-independent manner. These processes include cancer metastasis, vascular calcification, and renal fibrosis. This review covers the recent advances in Klotho research and discusses novel Klotho-dependent mechanisms that are clinically relevant in aging and age-related diseases.
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Yanochko GM, Vitsky A, Heyen JR, Hirakawa B, Lam JL, May J, Nichols T, Sace F, Trajkovic D, Blasi E. Pan-FGFR inhibition leads to blockade of FGF23 signaling, soft tissue mineralization, and cardiovascular dysfunction. Toxicol Sci 2013; 135:451-64. [PMID: 23872713 DOI: 10.1093/toxsci/kft161] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The fibroblast growth factor receptors (FGFR) play a major role in angiogenesis and are desirable targets for the development of therapeutics. Groups of Wistar Han rats were dosed orally once daily for 4 days with a small molecule pan-FGFR inhibitor (5mg/kg) or once daily for 6 days with a small molecule MEK inhibitor (3mg/kg). Serum phosphorous and FGF23 levels increased in all rats during the course of the study. Histologically, rats dosed with either drug exhibited multifocal, multiorgan soft tissue mineralization. Expression levels of the sodium phosphate transporter Npt2a and the vitamin D-metabolizing enzymes Cyp24a1 and Cyp27b1 were modulated in kidneys of animals dosed with the pan-FGFR inhibitor. Both inhibitors decreased ERK phosphorylation in the kidneys and inhibited FGF23-induced ERK phosphorylation in vitro in a dose-dependent manner. A separate cardiovascular outcome study was performed to monitor hemodynamics and cardiac structure and function of telemetered rats dosed with either the pan-FGFR inhibitor or MEK inhibitor for 3 days. Both compounds increased blood pressure (~+ 17 mmHg), decreased heart rate (~-75 bpm), and modulated echocardiography parameters. Our data suggest that inhibition of FGFR signaling following administration of either pan-FGFR inhibitor or MEK inhibitor interferes with the FGF23 pathway, predisposing animals to hyperphosphatemia and a tumoral calcinosis-like syndrome in rodents.
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Huang X, Jiang Y, Xia W. FGF23 and Phosphate Wasting Disorders. Bone Res 2013; 1:120-32. [PMID: 26273497 DOI: 10.4248/br201302002] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 04/25/2013] [Indexed: 11/10/2022] Open
Abstract
A decade ago, only two hormones, parathyroid hormone and 1,25(OH)2D, were widely recognized to directly affect phosphate homeostasis. Since the discovery of fibroblast growth factor 23 (FGF23) in 2000 (1), our understanding of the mechanisms of phosphate homeostasis and of bone mineralization has grown exponentially. FGF23 is the link between intestine, bone, and kidney together in phosphate regulation. However, we still do not know the complex mechanism of phosphate homeostasis and bone mineralization. The physiological role of FGF23 is to regulate serum phosphate. Secreted mainly by osteocytes and osteoblasts in the skeleton (2,3), it modulates kidney handling of phosphate reabsorption and calcitriol production. Genetic and acquired abnormalities in FGF23 structure and metabolism cause conditions of either hyper-FGF23 or hypo-FGF23. Hyper-FGF23 is related to hypophosphatemia, while hypo-FGF23 is related to hyperphosphatemia. Both hyper-FGF23 and hypo-FGF23 are detrimental to humans. In this review, we will discuss the pathophysiology of FGF23 and hyper-FGF23 related renal phosphate wasting disorders (4).
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Affiliation(s)
- Xianglan Huang
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences , Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing 100730, China
| | - Yan Jiang
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences , Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing 100730, China
| | - Weibo Xia
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences , Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing 100730, China
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Hartman ML, Groppo F, Ohnishi M, Goodson JM, Hasturk H, Tavares M, Yaskell T, Floras C, Behbehani K, Razzaque MS. Can salivary phosphate levels be an early biomarker to monitor the evolvement of obesity? CONTRIBUTIONS TO NEPHROLOGY 2013; 180:138-48. [PMID: 23652556 PMCID: PMC3896993 DOI: 10.1159/000346793] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Phosphate is an essential nutrient required for important biological reactions that maintain the normal homoeostatic control of the cell. The adverse effects of phosphate metabolism in obesity have not been studied in detail, chiefly because such an association is thought to be uncommon. However, in some animal models of obesity, serum phosphate levels were noted to be higher than the nonobese controls. For example, leptin-deficient (ob/ob) mice become severely obese and have high serum phosphate levels. In this study, we analyzed the phosphate content in saliva collected from children (n = 77; 10.5 ± 1.8) to evaluate association with body mass index; there is a significant increase of salivary phosphate content in obese compared to normal-weight children (ANOVA p < 0.001). The correlation coefficient (r) between BMI and phosphate was 0.33 (p = 0.0032). Our results suggest that the human salivary phosphate level may be an early biomarker of the genesis of obesity in children. The diagnostic importance lies in the fact that the salivary phosphate level could provide a noninvasive predictive marker in the development of obesity. Further studies will be required to understand the underlying mechanism of increased salivary phosphate accumulation in obese and overweight children. Nevertheless, its occurrence without systemic changes could be of diagnostic value, particularly in monitoring evolvement of obesity.
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Affiliation(s)
- Mor-Li Hartman
- Department of Applied Oral Sciences, The Forsyth Institute, Cambridge, Mass
| | - Francisco Groppo
- Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil
| | - Mutsuko Ohnishi
- Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, Mass., USA
| | - J. Max Goodson
- Department of Applied Oral Sciences, The Forsyth Institute, Cambridge, Mass
| | - Hatice Hasturk
- Department of Applied Oral Sciences, The Forsyth Institute, Cambridge, Mass
| | - Mary Tavares
- Department of Applied Oral Sciences, The Forsyth Institute, Cambridge, Mass
| | - Tina Yaskell
- Department of Applied Oral Sciences, The Forsyth Institute, Cambridge, Mass
| | - Constantino Floras
- Department of Applied Oral Sciences, The Forsyth Institute, Cambridge, Mass
| | | | - Mohammed S. Razzaque
- Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, Mass., USA
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Fujiwara M, Namba N, Ozono K, Arisaka O, Yokoya S. Treatment of Hypophosphatemic Rickets with Phosphate and Active Vitamin D in Japan: A Questionnaire-based Survey. Clin Pediatr Endocrinol 2013. [PMID: 23966755 PMCID: PMC3748281 DOI: 10.1297/cpe.22.9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Hereditary hypophosphatemic rickets represented
by X-linked hypophosphatemic rickets (XLH) is a rare disorder characterized by
hypophosphatemia, elevated alkaline phosphatase (ALP) and undermineralization of bone.
Active vitamin D and phosphate are administered to correct hypophosphatemia and elevation
of ALP. Overtreatment with phosphate leads to secondary hyperparathyroidism, and a large
dose of active vitamin D has a risk of hypercalciuria. To understand the situation
concerning treatment of patients with hereditary hypophosphatemic rickets in Japan, we
conducted a questionnaire survey of pediatric endocrinologists. Answers were obtained from
53 out of 68 hospitals where the pediatric endocrinologists worked. One hundred and
thirty-five patients were treated in 28 hospitals during November 2009 and May 2010; 126
patients suffered from hereditary hypophosphatemic rickets, and 9 had hypophosphatemia
caused by other miscellaneous reasons. The distribution of patient age was as follows: 27
(21%) were between 6 mo and 6 yr of age, 39 (31%) were between 6 and 12 yr of age, and 60
(48%) were more than 12 yr of age. Active vitamin D was given to 123 patients, and
phosphate was given to 106 patients. As for the dose of phosphorus, 37.2–58.1 mg/kg/d was
given divided into 2 to 6 aliquots. There were various control targets of treatment,
including serum phosphate, serum ALP, rachitic change, urinary Ca/Cr, parathyroid hormone
and growth. It is very important to avoid side effects of these treatments. No evidence is
available about the optimal dose of phosphate or number of administrations in the
treatment of patients with hypophosphatemic rickets. Although there is a recommendation
for clinical management of patients with hypophosphatemic rickets, we should set a
clinical guideline for it in Japan.
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Affiliation(s)
- Makoto Fujiwara
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
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Abstract
Rickets is characterized by impaired mineralization and ossification of the growth plates of growing children caused by a variety of disorders, the most frequent of which is nutritional deficiency of vitamin D. Despite ample knowledge of its etiology and the availability of cost-effective methods of preventing it, vitamin D deficiency rickets remains a significant problem in developing and developed countries. This two-part review covers the history, etiology, pathophysiology and clinical and radiographical findings of vitamin D deficiency rickets. Other less frequent causes of rickets and some of the disorders entering into the differential diagnoses of rickets are also considered. Controversial issues surrounding vitamin D deficiency include determination of what constitutes vitamin D sufficiency and the potential relationship between low levels of vitamin D metabolites in many individuals and unexplained fractures in infants.
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Affiliation(s)
- Richard M Shore
- Department of Medical Imaging, Box 9, Ann & Robert H. Lurie Children's Hospital of Chicago, 225 E. Chicago Ave., Chicago, IL 60611, USA.
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Abstract
Phosphate is one of the most abundant minerals in the body, and its serum levels are regulated by a complex set of processes occurring in the intestine, skeleton, and kidneys. The currently known main regulators of phosphate homeostasis include parathyroid hormone (PTH), calcitriol, and a number of peptides collectively known as the "phosphatonins" of which fibroblast growth factor-23 (FGF-23) has been best defined. Maintenance of extracellular and intracellular phosphate levels within a narrow range is important for many biological processes, including energy metabolism, cell signaling, regulation of protein synthesis, skeletal development, and bone integrity. The presence of adequate amounts of phosphate is critical for the process of apoptosis of mature chondrocytes in the growth plate. Without the presence of this mineral in high enough quantities, chondrocytes will not go into apoptosis, and the normal physiological chain of events that includes invasion of blood vessels and the generation of new bone will be blocked, resulting in rickets and delayed growth. In the rest of the skeleton, hypophosphatemia will result in osteomalacia due to an insufficient formation of hydroxyapatite. This review will address phosphate metabolism and its role in bone health.
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Abstract
A disproportionate expansion of white adipose tissue and abnormal recruitment of adipogenic precursor cells can not only lead to obesity but also impair glucose metabolism, which are both common causes of insulin resistance and diabetes mellitus. The development of novel and effective therapeutic strategies to slow the progression of obesity, diabetes mellitus and their associated complications will require improved understanding of adipogenesis and glucose metabolism. Klotho might have a role in adipocyte maturation and systemic glucose metabolism. Klotho increases adipocyte differentiation in vitro, and mice that lack Klotho activity are lean owing to reduced white adipose tissue accumulation; moreover, mice that lack the Kl gene (which encodes Klotho) are resistant to obesity induced by a high-fat diet. Knockout of Kl in leptin-deficient Lep(ob/ob) mice reduces obesity and increases insulin sensitivity, which lowers blood glucose levels. Energy metabolism might also be influenced by Klotho. However, further studies are needed to explore the possibility that Klotho could be a novel therapeutic target to reduce obesity and related complications, and to determine whether and how Klotho might influence the regulation and function of a related protein, β-Klotho, which is also involved in energy metabolism.
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Affiliation(s)
- M Shawkat Razzaque
- Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Research and Education Building, Room 304, 190 Longwood Avenue, Boston, MA 02115, USA.
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Gattineni J, Baum M. Genetic disorders of phosphate regulation. Pediatr Nephrol 2012; 27:1477-87. [PMID: 22350303 PMCID: PMC3407352 DOI: 10.1007/s00467-012-2103-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Revised: 12/08/2011] [Accepted: 12/09/2011] [Indexed: 12/21/2022]
Abstract
Regulation of phosphate homeostasis is critical for many biological processes, and both hypophosphatemia and hyperphosphatemia can have adverse clinical consequences. Only a very small percentage (1%) of total body phosphate is present in the extracellular fluid, which is measured by routine laboratory assays and does not reflect total body phosphate stores. Phosphate is absorbed from the gastrointestinal tract via the transcellular route [sodium phosphate cotransporter 2b (NaPi2b)] and across the paracellular pathway. Approximately 85% of the filtered phosphate is reabsorbed from the kidney, predominantly in the proximal tubule, by NaPi2a and NaPi2c, which are present on the brush border membrane. Renal phosphate transport is tightly regulated. Dietary phosphate intake, parathyroid hormone (PTH), 1,25 (OH)2 vitamin D3, and fibroblast growth factor 23 (FGF23) are the principal regulators of phosphate reabsorption from the kidney. Recent advances in genetic techniques and animal models have identified many genetic disorders of phosphate homeostasis. Mutations in NaPi2a and NaPi2c; and hormonal dysregulation of PTH, FGF23, and Klotho, are primarily responsible for most genetic disorders of phosphate transport. The main focus of this educational review article is to discuss the genetic and clinical features of phosphate regulation disorders and provide understanding and treatment options.
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Affiliation(s)
- Jyothsna Gattineni
- Department of Pediatrics, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75235-9063, USA.
| | - Michel Baum
- Department of Pediatrics, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75235-9063 USA ,Department of Internal Medicine, University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75235-9063 USA
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40
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Siomou E, Stefanidis CJ. FGF-23 in children with CKD: a new player in the development of CKD-mineral and bone disorder. Nephrol Dial Transplant 2012; 27:4259-62. [PMID: 22848110 DOI: 10.1093/ndt/gfs315] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Disturbances in mineral and bone metabolism in children with chronic kidney disease (CKD) lead to specific abnormalities of skeletal homeostasis called CKD-mineral and bone disorder (CKD-MBD). These disturbances should be diagnosed and managed appropriately to prevent bone deformities and disturbed growth. Changes in the vitamin D and parathyroid hormone (PTH), and the subsequent alterations in calcium (Ca) and phosphate (P) homeostasis are considered responsible for the development of CKD-MBD. Recently, a phosphaturic hormone, the fibroblast growth factor-23 (FGF-23), has been reported as a key regulator of P and vitamin D metabolism. A number of recent studies in paediatric populations have documented that the FGF-23 levels are increased early in CKD, before any abnormalities in serum Ca, P or PTH are apparent. The elevated FGF-23 levels result in a negative P balance to maintain P homeostasis, inducing phosphaturia, independently of PTH, and suppressing vitamin D synthesis. Therefore, the bone-kidney-parathyroid endocrine axis mediated by FGF-23 should be a novel therapeutic target in clinical practice, even in early stages of CKD in children.
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Affiliation(s)
- Ekaterini Siomou
- Department of Child Health, Medical School, University of Ioannina, Ioannina, Greece.
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41
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Munoz J, Michel Ortega R, Celzo F, Donthireddy V. 'Tumour-induced osteomalacia'. BMJ Case Rep 2012; 2012:bcr.03.2012.5975. [PMID: 22736784 DOI: 10.1136/bcr.03.2012.5975] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
A 60-year-old man presented 2 years before his diagnosis with long-standing muscle cramping, progressive generalised weakness and chronic hip pain. The patient was found to have bilateral femoral neck pathologic fractures therefore, underwent reamed intramedullary nailing of both femurs. Laboratory studies showed hypophosphataemia. Bone marrow biopsy was negative for malignancy. Positron emission tomography demonstrated fludeoxyglucose uptake only in the posterior neck. Bone scan showed innumerable foci of increased activity throughout the skeleton consistent with pseudofractures seen in osteomalacia. Fine needle aspiration from the mass in the neck revealed a phosphaturic mesenchymal tumour of mixed connective tissue type. Resection of the mass in the neck resulted in resolution of generalised complaints with no evidence of recurrence with a follow-up of 12 months.
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Affiliation(s)
- Javier Munoz
- Department of Hematology and Oncology, Henry Ford Hospital, Detroit, Michigan, USA.
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42
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Palmer BF, Glassock RJ, Bleyer AJ. Nephrology Quiz and Questionnaire: Electrolytes. Clin J Am Soc Nephrol 2012; 7:1047-52. [DOI: 10.2215/cjn.01720212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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43
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Markou A, Tsiama V, Tournis S, Papanastasiou L, Tsiavos V, Dassou A, Vlachou V, Papaliodi E, Asimaki N, Zografos G, Piaditis G. Coexistence of tumor-induced osteomalacia and primary hyperparathyroidism. Endocr Pract 2012; 17:e144-8. [PMID: 21940278 DOI: 10.4158/ep11177.cr] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVE To present an unusual case of coexisting tumor-induced osteomalacia (TIO) and primary hyperparathyroidism (PHPT). METHODS We report the clinical features, imaging studies, and the results of laboratory investigations before and after surgical resection of both a soft-tissue tumor and a parathyroid adenoma. RESULTS A 44-year-old woman was referred to the endocrinology department with a diagnosis of PHPT accompanied by unusually severe hypophosphatemia, despite having received treatment with cinacalcet. Debilitating muscle weakness and bone pain, severe phosphaturia and hypophosphatemia, inappropriately normal calcitriol, and elevated fibroblast growth factor-23 and intact parathyroid hormone levels raised the suspicion of coexisting TIO and PHPT. Imaging studies were negative, but histologic characteristics of a palpable subcutaneous mass from the patient's thigh revealed a phosphaturic mesenchymal tumor. Complete remission after surgical removal of both the soft-tissue tumor and the parathyroid adenoma confirmed the diagnosis. CONCLUSION The coexistence of TIO and PHPT has not been described before and can cause life-threatening hypophosphatemia. Diagnosis and localization of the tumor is of paramount importance since surgery is the treatment of choice for both TIO and PHPT.
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Affiliation(s)
- Athina Markou
- Department of Endocrinology and Diabetes Center, G. Gennimatas Hospital, Athens, Greece.
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Wang H, Peng W, Ouyang X, Dai Y. Reduced Circulating miR-15b Is Correlated with Phosphate Metabolism in Patients with End-Stage Renal Disease on Maintenance Hemodialysis. Ren Fail 2012; 34:685-90. [DOI: 10.3109/0886022x.2012.676491] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
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45
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Moreira Guimarães Penido MG, de Sousa Tavares M. Bone disease in pediatric idiopathic hypercalciuria. World J Nephrol 2012; 1:54-62. [PMID: 24175242 PMCID: PMC3782196 DOI: 10.5527/wjn.v1.i2.54] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2011] [Revised: 11/11/2011] [Accepted: 02/10/2012] [Indexed: 02/06/2023] Open
Abstract
Idiopathic hypercalciuria (IH) is the leading metabolic risk factor for urolithiasis and affects all age groups without gender or race predominance. IH has a high morbidity with or without lithiasis and reduced bone mineral density (BMD), as described previously in pediatric patients as well as in adults. The pathogenesis of IH is complex and not completely understood, given that urinary excretion of calcium is the end result of an interplay between three organs (gut, bone and kidney), which is further orchestrated by hormones, such as 1,25 dihydroxyvitamin D, parathyroid hormone, calcitonin and fosfatonins (i.e., fibroblast growth-factor-23). Usually, a primary defect in one organ induces compensatory mechanisms in the remaining two organs, such as increased absorption of calcium in the gut secondary to a primary renal loss. Thus, IH is a systemic abnormality of calcium homeostasis with changes in cellular transport of this ion in intestines, kidneys and bones. Reduced BMD has been demonstrated in pediatric patients diagnosed with IH. However, the precise mechanisms of bone loss or failure of adequate bone mass gain are still unknown. The largest accumulation of bone mass occurs during childhood and adolescence, peaking at the end of the second decade of life. This accumulation should occur without interference to achieve the peak of optimal bone mass. Any interference may be a risk factor for the reduction of bone mass with increased risk of fractures in adulthood. This review will address the pathogenesis of IH and its consequence in bone mass.
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Affiliation(s)
- Maria Goretti Moreira Guimarães Penido
- Maria Goretti Moreira Guimarães Penido, Marcelo de Sousa Tavares, Department of Pediatrics, Pediatric Nephrology Unit, School of Medicine, Federal University of Minas Gerais, Belo Horizonte, Belo Horizonte, CEP 30130100, Minas Gerais, Brazil
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46
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Secreted klotho and chronic kidney disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 728:126-57. [PMID: 22396167 DOI: 10.1007/978-1-4614-0887-1_9] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Soluble Klotho (sKl) in the circulation can be generated directly by alterative splicing of the Klotho transcript or the extracellular domain of membrane Klotho can be released from membrane-anchored Klotho on the cell surface. Unlike membrane Klotho which functions as a coreceptor for fibroblast growth factor-23 (FGF23), sKl, acts as hormonal factor and plays important roles in anti-aging, anti-oxidation, modulation of ion transport, and Wnt signaling. Emerging evidence reveals that Klotho deficiency is an early biomarker for chronic kidney diseases as well as a pathogenic factor. Klotho deficiency is associated with progression and chronic complications in chronic kidney disease including vascular calcification, cardiac hypertrophy, and secondary hyperparathyroidism. In multiple experimental models, replacement of sKl, or manipulated up-regulation of endogenous Klotho protect the kidney from renal insults, preserve kidney function, and suppress renal fibrosis, in chronic kidney disease. Klotho is a highly promising candidate on the horizon as an early biomarker, and as a novel therapeutic agent for chronic kidney disease.
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47
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Bacchetta J, Salusky IB. Evaluation of hypophosphatemia: lessons from patients with genetic disorders. Am J Kidney Dis 2011; 59:152-9. [PMID: 22075221 DOI: 10.1053/j.ajkd.2011.08.035] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Accepted: 08/12/2011] [Indexed: 12/20/2022]
Abstract
Phosphate is a key component of several physiologic pathways, such as skeletal development, bone mineralization, membrane composition, nucleotide structure, maintenance of plasma pH, and cellular signaling. The kidneys have a key role in phosphate homeostasis, with 3 hormones having important roles in renal phosphate handling: parathyroid hormone, fibroblast growth factor 23 (FGF-23), and 1,25-dihydroxyvitamin D. Independent of the genetic diseases affecting the FGF-23 pathway (such as hypophosphatemic rickets), hypophosphatemia is a frequent condition encountered in daily practice, and untreated critical hypophosphatemia can induce hemolysis, rhabdomyolysis, respiratory failure, cardiac dysfunction, and neurologic impairment. Rapid correction thus is necessary to avoid severe complications. The aims of this teaching case are to summarize the causes and biological evaluation of hypophosphatemia and provide an overview of our current understanding of phosphate metabolism.
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Affiliation(s)
- Justine Bacchetta
- David Geffen School of Medicine, Division of Pediatric Nephrology, University of California Los Angeles, Los Angeles, CA 90095, USA
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48
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Gattineni J, Twombley K, Goetz R, Mohammadi M, Baum M. Regulation of serum 1,25(OH)2 vitamin D3 levels by fibroblast growth factor 23 is mediated by FGF receptors 3 and 4. Am J Physiol Renal Physiol 2011; 301:F371-7. [PMID: 21561999 PMCID: PMC3154596 DOI: 10.1152/ajprenal.00740.2010] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2010] [Accepted: 05/08/2011] [Indexed: 12/29/2022] Open
Abstract
Fibroblast growth factor 23 (FGF23) is a phosphaturic hormone implicated in the pathogenesis of several hypophosphatemic disorders. FGF23 causes hypophosphatemia by decreasing the expression of sodium phosphate cotransporters (NaPi-2a and NaPi-2c) and decreasing serum 1,25(OH)(2)Vitamin D(3) levels. We previously showed that FGFR1 is the predominant receptor for the hypophosphatemic actions of FGF23 by decreasing renal NaPi-2a and 2c expression while the receptors regulating 1,25(OH)(2)Vitamin D(3) levels remained elusive. To determine the FGFRs regulating 1,25(OH)(2)Vitamin D(3) levels, we studied FGFR3(-/-)FGFR4(-/-) mice as these mice have shortened life span and are growth retarded similar to FGF23(-/-) and Klotho(-/-) mice. Baseline serum 1,25(OH)(2)Vitamin D(3) levels were elevated in the FGFR3(-/-)FGFR4(-/-) mice compared with wild-type mice (102.2 ± 14.8 vs. 266.0 ± 34.0 pmol/l; P = 0.001) as were the serum levels of FGF23. Administration of recombinant FGF23 had no effect on serum 1,25(OH)(2)Vitamin D(3) in the FGFR3(-/-)FGFR4(-/-) mice (173.4 ± 32.7 vs. 219.7 ± 56.5 pmol/l; vehicle vs. FGF23) while it reduced serum 1,25(OH)(2)Vitamin D(3) levels in wild-type mice. Administration of FGF23 to FGFR3(-/-)FGFR4(-/-) mice resulted in a decrease in serum parathyroid hormone (PTH) levels and an increase in serum phosphorus levels mediated by increased renal phosphate reabsorption. These data indicate that FGFR3 and 4 are the receptors that regulate serum 1,25(OH)(2)Vitamin D(3) levels in response to FGF23. In addition, when 1,25(OH)(2)Vitamin D(3) levels are not affected by FGF23, as in FGFR3(-/-)FGFR4(-/-) mice, a reduction in PTH can override the effects of FGF23 on renal phosphate transport.
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Affiliation(s)
- Jyothsna Gattineni
- Dept. of Pediatrics, U.T. Southwestern Medical Center, Dallas, TX 75390-9063, USA.
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Serum osteoprotegerin, RANKL and fibroblast growth factor-23 in children with chronic kidney disease. Pediatr Nephrol 2011; 26:1105-14. [PMID: 21479768 DOI: 10.1007/s00467-011-1870-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2010] [Revised: 03/11/2011] [Accepted: 03/14/2011] [Indexed: 01/08/2023]
Abstract
Osteoprotegerin (OPG), receptor activator of the nuclear factor κB ligand (RANKL) and fibroblast growth factor-23 (FGF-23) play a central role in renal osteodystrophy. We evaluated OPG/RANKL and FGF-23 levels in 51 children with chronic kidney disease (CKD) [n = 26 stage 3 or 4 (CKD3-4) and n = 25 stage 5 (CKD5)] and 61 controls. Any possible association with intact parathyroid hormone (iPTH) and bone turnover markers was also investigated. The OPG levels were lower in the CKD3-4 group (p < 0.001) and higher in the CKD5 group (p < 0.01) than in the controls, while RANKL levels did not differ. The FGF-23 levels were higher in both patient groups (p < 0.0001), while the levels of phosphate and iPTH were higher only in the CKD5 group (p < 0.0001). There were independent positive correlations between OPG and RANKL (β = 0.297, p < 0.01) and FGF-23 (β = 0.352, p < 0.05) and a negative correlation with the bone resorption marker TRAP5b (β = -0.519, p < 0.001). OPG was positively correlated with iPTH (R = 0.391, p < 0.01). An independent positive correlation between FGF-23 and phosphate (β = 0.368, p < 0.05) or iPTH (β = 0.812, p < 0.0001) was noted. In conclusion, we found that higher OPG levels in patients with CKD stage 5 correlated with the levels of RANKL, FGF-23, iPTH, and TRAP5b. These findings may reflect a compensatory mechanism to the negative balance of bone turnover. High FGF-23 levels in early CKD stages may indicate the need for intervention to manage serum phosphate (Pi) levels.
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50
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Bacchetta J, Cochat P, Salusky IB. [FGF23 and Klotho: the new cornerstones of phosphate/calcium metabolism]. Arch Pediatr 2011; 18:686-95. [PMID: 21497493 PMCID: PMC4292917 DOI: 10.1016/j.arcped.2011.03.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2010] [Revised: 01/21/2011] [Accepted: 03/08/2011] [Indexed: 12/18/2022]
Abstract
Since its first description as a phosphaturic agent in the early 2000s, fibroblast growth factor 23 (FGF23) has rapidly become the third key player of phosphate/calcium metabolism after PTH and vitamin D. FGF23 is a protein synthesized by osteocytes that acts mainly as a phosphaturic factor and a suppressor of 1α hydroxylase activity in the kidney. It inhibits the expression of type IIa and IIc sodium-phosphate cotransporters on the apical membrane of proximal tubular cells, thus leading to inhibition of phosphate reabsorption. Moreover, it also inhibits 1α hydroxylase activity. These two renal pathways account together for the hypophosphatemic effect of FGF23, but FGF23 has also been recently described as an inhibiting factor for PTH synthesis. Its exact role in bone remains to be defined. A transmembrane protein, Klotho, is an essential cofactor for FGF23 biological activity, but it can also act by itself for calcium and PTH regulation. This paper gives an overview of these recent data of phosphate/calcium physiology, as well as a description of clinical conditions associated with FGF23 deregulation (genetic diseases and chronic kidney disease). As a conclusion, future therapeutic consequences of the FGF23/Klotho axis are discussed.
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Affiliation(s)
- J Bacchetta
- Centre de référence des maladies rénales rares, hôpital Femme-Mère-Enfant, boulevard Pinel, 69677 Bron cedex, France
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