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Christodoulou M, Aspray TJ, Piec I, Fraser WD, Schoenmakers I. Alterations in regulators of the renal-bone axis, inflammation and iron status in older people with early renal impairment and the effect of vitamin D supplementation. Age Ageing 2024; 53:afae096. [PMID: 38770543 PMCID: PMC11106582 DOI: 10.1093/ageing/afae096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 03/21/2024] [Indexed: 05/22/2024] Open
Abstract
CONTEXT Chronic kidney disease (CKD) leads to alterations in fibroblast growth factor 23 (FGF23) and the renal-bone axis. This may be partly driven by altered inflammation and iron status. Vitamin D supplementation may reduce inflammation. OBJECTIVE AND METHODS Older adults with early CKD (estimated glomerular filtration rate (eGFR) 30-60 ml/min/1.73 m2; CKDG3a/b; n = 35) or normal renal function (eGFR >90 ml/min/1.73 m2; CKDG1; n = 35) received 12,000, 24,000 or 48,000 IU D3/month for 1 year. Markers of the renal-bone axis, inflammation and iron status were investigated pre- and post-supplementation. Predictors of c-terminal and intact FGF23 (cFGF23; iFGF23) were identified by univariate and multivariate regression. RESULTS Pre-supplementation, comparing CKDG3a/b to CKDG1, plasma cFGF23, iFGF23, PTH, sclerostin and TNFα were significantly higher and Klotho, 1,25-dihydroxyvitamin D and iron were lower. Post-supplementation, only cFGF23, 25(OH)D and IL6 differed between groups. The response to supplementation differed between eGFR groups. Only in the CKDG1 group, phosphate decreased, cFGF23, iFGF23 and procollagen type I N-propeptide increased. In the CKDG3a/b group, TNFα significantly decreased, and iron increased. Plasma 25(OH)D and IL10 increased, and carboxy-terminal collagen crosslinks decreased in both groups. In univariate models cFGF23 and iFGF23 were predicted by eGFR and regulators of calcium and phosphate metabolism at both time points; IL6 predicted cFGF23 (post-supplementation) and iFGF23 (pre-supplementation) in univariate models. Hepcidin predicted post-supplementation cFGF23 in multivariate models with eGFR. CONCLUSION Alterations in regulators of the renal-bone axis, inflammation and iron status were found in early CKD. The response to vitamin D3 supplementation differed between eGFR groups. Plasma IL6 predicted both cFGF23 and iFGF23 and hepcidin predicted cFGF23.
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Affiliation(s)
| | - Terence J Aspray
- Freeman Hospital, Bone Clinic, University of Newcastle upon Tyne, Newcastle upon Tyne, UK
| | - Isabelle Piec
- University of East Anglia, Norwich Medical School, Norwich, UK
| | - William D Fraser
- University of East Anglia, Norwich Medical School, Norwich, UK
- Clinical Biochemistry, Department of Laboratory Medicine and Department of Diabetes and Endocrinology, Norfolk and Norwich University Hospital NHS Foundation Trust, Norwich, UK
| | - Inez Schoenmakers
- University of East Anglia, Norwich Medical School, Norwich, UK
- MRC Human Nutrition Research, Cambridge, UK
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Bosman A, Campos-Obando N, de Keyser CE, Stricker BH, Zillikens MC. Diuretic Use and Serum Phosphate: Rotterdam Study and UK Biobank. J Endocr Soc 2024; 8:bvae057. [PMID: 38572420 PMCID: PMC10989188 DOI: 10.1210/jendso/bvae057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Indexed: 04/05/2024] Open
Abstract
Purpose Hypophosphatemia (serum phosphate < 0.80 mmol/L) leads to musculoskeletal complaints. The most common drugs linked to hypophosphatemia are thiazide and loop diuretics, but studies in the general population are lacking. Our aim was to study associations between diuretic use and serum phosphate in the Rotterdam Study (RS), a population-based cohort study, with replication in UK Biobank (UKBB). Methods Associations between thiazide and loop diuretic use and serum phosphate and odds of hypophosphatemia were analyzed with cross-sectional multivariate linear and logistic regression in participants without chronic kidney disease in the RS and UKBB. Analyses were adjusted for age, sex, and body mass index (BMI) and pooled in 3 RS cohorts with further adjustment for cohort and serum potassium, which was not available in UKBB. Results Thiazide diuretics were associated with lower serum phosphate in both sexes. This association lost significance in RS females after adjustment for BMI and in males after adjustment for serum potassium. Thiazide diuretics increased odds of hypophosphatemia in females in both cohorts and in males in UKBB only. Loop diuretics were associated with lower serum phosphate in females but not males. Adjustment for BMI attenuated these associations. Associations between loop diuretics and increased odds of hypophosphatemia in females lost significance after BMI adjustment. Conclusion Thiazides, but not loop diuretics, and increased BMI and decreased serum potassium should be considered as contributing factors in subjects with hypophosphatemia. Further studies are needed to replicate the findings and elucidate the potential role of hypokalemia as a mediator of this effect.
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Affiliation(s)
- Ariadne Bosman
- Department of Internal Medicine, Erasmus MC, University Medical Center, 3015 GD Rotterdam, The Netherlands
| | - Natalia Campos-Obando
- Department of Internal Medicine, Erasmus MC, University Medical Center, 3015 GD Rotterdam, The Netherlands
| | - Catherine E de Keyser
- Department of Internal Medicine, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands
| | - Bruno H Stricker
- Department of Epidemiology, Erasmus MC, University Medical Center, 3015 GD Rotterdam, The Netherlands
| | - M Carola Zillikens
- Department of Internal Medicine, Erasmus MC, University Medical Center, 3015 GD Rotterdam, The Netherlands
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Bosman A, Appelman-Dijkstra NM, Boot AM, de Borst MH, van de Ven AC, de Jongh RT, Bökenkamp A, van den Bergh JP, van der Eerden BCJ, Zillikens MC. Disease Manifestations and Complications in Dutch X-Linked Hypophosphatemia Patients. Calcif Tissue Int 2024; 114:255-266. [PMID: 38226986 PMCID: PMC10901935 DOI: 10.1007/s00223-023-01172-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Accepted: 11/27/2023] [Indexed: 01/17/2024]
Abstract
X-linked hypophosphatemia (XLH) is the most common monogenetic cause of chronic hypophosphatemia, characterized by rickets and osteomalacia. Disease manifestations and treatment of XLH patients in the Netherlands are currently unknown. Characteristics of XLH patients participating in the Dutch observational registry for genetic hypophosphatemia and acquired renal phosphate wasting were analyzed. Eighty XLH patients, including 29 children, were included. Genetic testing, performed in 78.8% of patients, showed a PHEX mutation in 96.8%. Median (range) Z-score for height was - 2.5 (- 5.5; 1.0) in adults and - 1.4 (- 3.7; 1.0) in children. Many patients were overweight or obese: 64.3% of adults and 37.0% of children. All children received XLH-related medication e.g., active vitamin D, phosphate supplementation or burosumab, while 8 adults used no medication. Lower age at start of XLH-related treatment was associated with higher height at inclusion. Hearing loss was reported in 6.9% of children and 31.4% of adults. Knee deformities were observed in 75.0% of all patients and osteoarthritis in 51.0% of adult patients. Nephrocalcinosis was observed in 62.1% of children and 33.3% of adults. Earlier start of XLH-related treatment was associated with higher risk of nephrocalcinosis and detection at younger age. Hyperparathyroidism longer than six months was reported in 37.9% of children and 35.3% of adults. This nationwide study confirms the high prevalence of adiposity, hearing loss, bone deformities, osteoarthritis, nephrocalcinosis and hyperparathyroidism in Dutch XLH patients. Early start of XLH-related treatment appears to be beneficial for longitudinal growth but may increase development of nephrocalcinosis.
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Affiliation(s)
- A Bosman
- Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, PO Box 2040, 3000, CA, Rotterdam, The Netherlands
| | - N M Appelman-Dijkstra
- Department of Internal Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - A M Boot
- Department of Pediatrics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - M H de Borst
- Department of Internal Medicine, University Medical Center Groningen, Groningen, The Netherlands
| | - A C van de Ven
- Department of Internal Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - R T de Jongh
- Department of Internal Medicine, Amsterdam University Medical Center, Vrije Universiteit, Amsterdam, The Netherlands
| | - A Bökenkamp
- Department of Pediatric Nephrology, Amsterdam University Medical Center, Emma Children's Hospital, Amsterdam, The Netherlands
| | - J P van den Bergh
- Department of Internal Medicine, VieCuri Medical Center, Venlo, The Netherlands
| | - B C J van der Eerden
- Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, PO Box 2040, 3000, CA, Rotterdam, The Netherlands
| | - M C Zillikens
- Department of Internal Medicine, Erasmus MC, University Medical Center Rotterdam, PO Box 2040, 3000, CA, Rotterdam, The Netherlands.
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Hawke K, Croft A, Lazarus S. Tumor-Induced Osteomalacia in a Patient with Crohn's Disease: A Case Report and Approach to Investigating Hypophosphatemia. Case Rep Gastroenterol 2024; 18:81-89. [PMID: 38410687 PMCID: PMC10896610 DOI: 10.1159/000536136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 01/03/2024] [Indexed: 02/28/2024] Open
Abstract
Introduction Hypophosphatemia occurs commonly in inflammatory bowel disease (IBD) patients and can cause considerable morbidity. The differential diagnoses in IBD include nutritional causes and hypophosphatemia induced by some formulations of intravenous iron infusions. Case Presentation We present the case of a 37-year-old man with active Crohn's disease, presenting with difficulty walking and fractures of the vertebrae and calcaneus. He had long-standing hypophosphatemia. Nutritional causes for hypophosphatemia were considered in the first instance given the presence of chronic diarrhea and vitamin D deficiency; however, there was minimal response to appropriate supplementation with oral phosphorous and vitamin D. Iron infusion-induced hypophosphatemia was then considered, but the nadir phosphate level preceded any iron infusion. Therefore, work-up was undertaken for less common causes. He was ultimately diagnosed with tumor-induced osteomalacia, caused by excess fibroblast growth factor 23 (FGF23) secretion from a phosphaturic mesenchymal tumor about the knee. He had complete resolution of symptoms and biochemical abnormalities following successful resection of the tumor. Conclusion This case illustrates the approach to investigation of hypophosphatemia in IBD patients. If the time course and response to phosphate supplementation are not as expected for nutritional or iron infusion-induced hypophosphatemia, less common causes should be considered.
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Affiliation(s)
- Kate Hawke
- Department of Diabetes and Endocrinology, Royal Brisbane and Women's Hospital, Herston, QLD, Australia
- Faculty of Medicine, University of Queensland, Brisbane, QLD, Australia
| | - Anthony Croft
- Faculty of Medicine, University of Queensland, Brisbane, QLD, Australia
- Department of Gastroenterology, Royal Brisbane and Women's Hospital, Herston, QLD, Australia
| | - Syndia Lazarus
- Department of Diabetes and Endocrinology, Royal Brisbane and Women's Hospital, Herston, QLD, Australia
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Shengir M, Fillebeen C, Wagner J, Ramanakumar AV, Kaouache M, Klein MB, Pantopoulos K, Sebastiani G. Increased Serum Fibroblast Growth Factor 23 Predicts Mortality in People With HIV/HCV Coinfection. J Acquir Immune Defic Syndr 2023; 94:273-279. [PMID: 37368933 DOI: 10.1097/qai.0000000000003245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 06/12/2023] [Indexed: 06/29/2023]
Abstract
BACKGROUND People with HIV and hepatitis C virus (HCV) coinfection experience excess mortality because of multiple causes. Identification of biomarkers associated with mortality beyond that attributable to liver fibrosis may be relevant for prognostication. Fibroblast growth factor 23 (FGF23), a phosphotropic hormone, predicts adverse outcomes in several chronic conditions. We aimed to investigate whether elevated FGF23 predicts all-cause mortality in patients with HIV/HCV coinfection. METHODS We included patients with HIV/HCV coinfection from the Canadian Coinfection Cohort with available serum FGF23, fibrosis biomarker fibrosis-4 (FIB-4), and at least 1-year follow-up. Elevated FGF23 and advanced liver fibrosis were defined as FGF23 > 241 reference unit/mL and FIB-4 > 3.25, respectively. All-cause mortality was analyzed using survival analysis. The effect of advanced liver fibrosis as a mediator on mortality was estimated by mediation analysis. RESULTS Three hundred twenty-one patients were included (24% with elevated FGF23, 19% with advanced liver fibrosis). During a mean follow-up period of 8.4 years, 34% of the cohort died. The incidence rate of all-cause mortality was higher in patients with elevated FGF23 (66.1 per 1000 person-years, 95% confidence interval 45.8 to 92.3) relative to patients without elevated FGF23 (37.5 per 1000 person-years, 95% confidence interval 29.6 to 46.9). After adjusting for potential confounders, elevated FGF23 was associated with significant direct and indirect effects (mediated through advanced liver fibrosis) on all-cause mortality, with 57% of deaths not mediated through advanced fibrosis. CONCLUSIONS In patients with HIV/HCV coinfection, FGF23 may be used as prognostic biomarker for risk stratification accounting also for death causes other than those attributable to liver fibrosis.
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Affiliation(s)
- Mohamed Shengir
- Division of Experimental Medicine, McGill University, Montreal, Quebec, Canada
| | - Carine Fillebeen
- Lady Davis Institute for Medical Research, McGill University, Montreal, Quebec, Canada
| | - John Wagner
- Lady Davis Institute for Medical Research, McGill University, Montreal, Quebec, Canada
| | | | - Mohammed Kaouache
- Research Institute, McGill University Health Centre, Montreal, Quebec, Canada; and
| | - Marina B Klein
- Chronic Viral Illness Services, McGill University Health Center, Montreal, Quebec, Canada
| | - Kostas Pantopoulos
- Lady Davis Institute for Medical Research, McGill University, Montreal, Quebec, Canada
| | - Giada Sebastiani
- Division of Experimental Medicine, McGill University, Montreal, Quebec, Canada
- Chronic Viral Illness Services, McGill University Health Center, Montreal, Quebec, Canada
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Hocher CF, Chen X, Zuo J, Horvathova K, Hocher B, Krämer BK, Chu C. Fibroblast growth factor 23 is associated with the development of gestational diabetes mellitus. Diabetes Metab Res Rev 2023; 39:e3704. [PMID: 37553983 DOI: 10.1002/dmrr.3704] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 07/01/2023] [Accepted: 07/12/2023] [Indexed: 08/10/2023]
Abstract
BACKGROUND Besides its established impact on bone and mineral metabolism, it was suggested that fibroblast growth factor 23 (FGF23) might play an important role in the pathogenesis of type 2 diabetes. The impact of FGF23 on gestational diabetes mellitus (GDM), however, is not well understood. iFGF23 ELISAs measure the intact FGF23 molecule, whereas cFGF23 assays measure intact FGF23 as well as degradation products of FGF23. OBJECTIVES The aim of this study is to compare the association of maternal and foetal cFGF23 and iFGF23 with GDM in a German birth cohort. METHODS cFGF23 and iFGF23 were analysed in 826 random mother/child pairs from the Berlin Birth Cohort. RESULTS Mothers who developed GDM had higher concentrations of iFGF-23 compared to mothers who did not suffer from GDM (19.73 vs. 13.23 pg/mL, p < 0.0001), but not higher concentrations of cFGF-23. Multivariant regression analyses showed that gestational diabetes is associated with iFGF23 independently of confounding factors such as age, BMI, ethnic background, family history of diabetes, smoking during pregnancy, and recurrent pregnancy loss. This, however, was only seen when using an iFGF23 ELISA measuring just the full length FGF23 and not in addition FGF23 fragments. No differences in both iFGF23 and cFGF23 concentrations between the GDM and non-GDM groups were detected in cord blood samples of the offspring. CONCLUSIONS This study of a representative German birth cohort showed that maternal but not foetal iFGF23 is independently associated with GDM.
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Affiliation(s)
- Carl-Friedrich Hocher
- Fifth Department of Medicine (Nephrology/Endocrinology/Rheumatology/ Pneumology), University Medical Centre Mannheim, University of Heidelberg, Mannheim, Germany
- Bundeswehrkrankenhaus Berlin, Berlin, Germany
| | - Xin Chen
- Fifth Department of Medicine (Nephrology/Endocrinology/Rheumatology/ Pneumology), University Medical Centre Mannheim, University of Heidelberg, Mannheim, Germany
- Department of Nephrology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Jiao Zuo
- Fifth Department of Medicine (Nephrology/Endocrinology/Rheumatology/ Pneumology), University Medical Centre Mannheim, University of Heidelberg, Mannheim, Germany
- Department of Nephrology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | | | - Berthold Hocher
- Fifth Department of Medicine (Nephrology/Endocrinology/Rheumatology/ Pneumology), University Medical Centre Mannheim, University of Heidelberg, Mannheim, Germany
- Institute of Medical Diagnostics, IMD Berlin-Potsdam, Berlin, Germany
- Reproductive and Genetic Hospital of CITIC-Xiangya, Changsha, China
| | - Bernhard K Krämer
- Fifth Department of Medicine (Nephrology/Endocrinology/Rheumatology/ Pneumology), University Medical Centre Mannheim, University of Heidelberg, Mannheim, Germany
- European Center for Angioscience ECAS, Medical Faculty Mannheim of the University of Heidelberg, Mannheim, Germany
- Center for Preventive Medicine and Digital Health Baden-Württemberg (CPDBW), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Chang Chu
- Fifth Department of Medicine (Nephrology/Endocrinology/Rheumatology/ Pneumology), University Medical Centre Mannheim, University of Heidelberg, Mannheim, Germany
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Liu Y, Cheng Y, Sun M, Hao X, Li M. Analysis of serum insulin-like growth factor-1, fibroblast growth factor 23, and Klotho levels in girls with rapidly progressive central precocious puberty. Eur J Pediatr 2023; 182:5007-5013. [PMID: 37644169 PMCID: PMC10640509 DOI: 10.1007/s00431-023-05174-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Revised: 08/19/2023] [Accepted: 08/22/2023] [Indexed: 08/31/2023]
Abstract
To study the levels of serum insulin-like growth factor 1 (IGF-1), fibroblast growth factor 23 (FGF23), and Klotho, and to study their relationship with girls with rapidly progressive central precocious puberty (RP-CPP). This is a cross-sectional study on the progression rate of central precocious puberty in girls, who complained of breast development before the age of 8 years and were followed between June 2021 and June 2022. At the same time, 28 healthy girls less than 8 years old who had not started puberty were recruited as the control group. The physical examination and laboratory evaluation of each group was completed. Only patients with CPP received pelvic ultrasound examination and bone age test. Bone age index (BAI), basal LH levels (BLH), basal LH levels/basal FSH levels (BFSH), peak LH (PLH)/peak FSH (PFSH), IGF-1, Klotho, FGF23, and ovarian volume in the RP-CPP group were higher than those in slowly progressive CPP (SP-CPP) group. In the RP-CPP group, IGF-1 was correlated with Klotho, FGF23, and BLH; Klotho was correlated with FGF23 and BLH; FGF23 was correlated with BLH. CONCLUSION The BLH, FGF23, Klotho, and IGF-1 have a certain correlation with RP-CPP, which may play an important role in the speed of girls' sexual development. WHAT IS KNOWN • The association between IGF-1 and RP-CPP. WHAT IS NEW • We found the association between FGF23, Klotho and RP-CPP.
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Affiliation(s)
- Yuping Liu
- Department of Pediatrics, Hebei General Hospital, 348 Heping West Road, Xinhua District, Shijiazhuang, Hebei, China
| | - Yaying Cheng
- Department of Pediatrics, Hebei General Hospital, 348 Heping West Road, Xinhua District, Shijiazhuang, Hebei, China.
| | - Meng Sun
- Department of Pediatrics, Hebei General Hospital, 348 Heping West Road, Xinhua District, Shijiazhuang, Hebei, China
| | - Xiaojing Hao
- Department of Pediatrics, Hebei General Hospital, 348 Heping West Road, Xinhua District, Shijiazhuang, Hebei, China
| | - Mengmeng Li
- Department of Pediatrics, Hebei General Hospital, 348 Heping West Road, Xinhua District, Shijiazhuang, Hebei, China
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Ratsma DMA, Muller M, Koedam M, Zillikens MC, van der Eerden BCJ. In vitro regulation of fibroblast growth factor 23 by 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D synthesized by osteocyte-like MC3T3-E1 cells. Eur J Endocrinol 2023; 189:448-459. [PMID: 37796032 DOI: 10.1093/ejendo/lvad131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 07/31/2023] [Accepted: 10/03/2023] [Indexed: 10/06/2023]
Abstract
Fibroblast growth factor 23 (FGF23) is produced and secreted by osteocytes and is essential for maintaining phosphate homeostasis. One of the main regulators of FGF23, 1,25-dihydroxyvitamin D (1,25(OH)2D3), is primarily synthesized in the kidney from 25-hydroxyvitamin D (25(OH)D) by 1α-hydroxylase (encoded by CYP27B1). Hitherto, it is unclear whether osteocytes can convert 25(OH)D and thereby allow for 1,25(OH)2D3 to induce FGF23 production and secretion locally. Here, we differentiated MC3T3-E1 cells toward osteocyte-like cells expressing and secreting FGF23. Treatment with 10-6 M 25(OH)D resulted in conversion of 25(OH)D to 150 pmol/L 1,25(OH)2D3 and increased FGF23 expression and secretion, but the converted amount of 1,25(OH)2D3 was insufficient to trigger an FGF23 response, so the effect on FGF23 was most likely directly caused by 25(OH)D. Interestingly, combining phosphate with 25(OH)D resulted in a synergistic increase in FGF23 expression and secretion, likely due to activation of additional signaling pathways by phosphate. Blockage of the vitamin D receptor (VDR) only partially abolished the effects of 25(OH)D or 25(OH)D combined with phosphate on Fgf23, while completely inhibiting the upregulation of cytochrome P450 family 24 subfamily A member 1 (Cyp24a1), encoding for 24-hydroxylase. RNA sequencing and in silico analyses showed that this could potentially be mediated by the nuclear receptors Retinoic Acid Receptor β (RARB) and Estrogen Receptor 2 (ESR2). Taken together, we demonstrate that osteocytes are able to convert 25(OH)D to 1,25(OH)2D3, but this is insufficient for FGF23 activation, implicating a direct effect of 25(OH)D in the regulation of FGF23, which occurs at least partially independent from its cognate VDR. Moreover, phosphate and 25(OH)D synergistically increase expression and secretion of FGF23, which warrants investigating consequences in patients receiving a combination of vitamin D analogues and phosphate supplements. These observations help us to further understand the complex relations between phosphate, vitamin D, and FGF23.
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Affiliation(s)
- Danielle M A Ratsma
- Laboratory for Calcium and Bone metabolism and Erasmus MC Bone Centre, Department of Internal Medicine, Erasmus University Medical Center, PO Box 2040, Rotterdam 3015 CN, The Netherlands
| | - Max Muller
- Laboratory for Calcium and Bone metabolism and Erasmus MC Bone Centre, Department of Internal Medicine, Erasmus University Medical Center, PO Box 2040, Rotterdam 3015 CN, The Netherlands
| | - Marijke Koedam
- Laboratory for Calcium and Bone metabolism and Erasmus MC Bone Centre, Department of Internal Medicine, Erasmus University Medical Center, PO Box 2040, Rotterdam 3015 CN, The Netherlands
| | - M Carola Zillikens
- Laboratory for Calcium and Bone metabolism and Erasmus MC Bone Centre, Department of Internal Medicine, Erasmus University Medical Center, PO Box 2040, Rotterdam 3015 CN, The Netherlands
| | - Bram C J van der Eerden
- Laboratory for Calcium and Bone metabolism and Erasmus MC Bone Centre, Department of Internal Medicine, Erasmus University Medical Center, PO Box 2040, Rotterdam 3015 CN, The Netherlands
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Bosman A, Ratsma DMA, van der Eerden BCJ, Zillikens MC. Case Report: Unexplained Mild Hypophosphatemia and Very High Serum FGF23 Concentrations. JBMR Plus 2023; 7:e10790. [PMID: 37808399 PMCID: PMC10556273 DOI: 10.1002/jbm4.10790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 06/07/2023] [Accepted: 06/10/2023] [Indexed: 10/10/2023] Open
Abstract
Fibroblast growth factor (FGF)23 is one of the major regulators of phosphate homeostasis. Hypophosphatemia can lead to muscle weakness, fatigue, and osteomalacia. In the setting of hypophosphatemia, serum FGF23 can be measured to differentiate between FGF23-mediated and non-FGF23-mediated renal phosphate wasting. C-terminal FGF23 (cFGF23) assays detect both cFGF23 and intact FGF23 (iFGF23). Circulating FGF23 is regulated by 1.25-dihydroxy-vitamin D, parathyroid hormone (PTH), serum phosphate, and serum calcium but also by, for example, iron status, inflammation, erythropoietin, and hypoxia-inducible-factor-1-α. We present the case of a 48-year-old woman with unexplained mild hypophosphatemia, very high cFGF23, and normal iFGF23. The patient proved to have an iron deficiency. Iron deficiency alters the iFGF23-to-cFGF23 ratio. After initiation of iron treatment, cFGF23 strongly decreased. This case report illustrates the limitation of cFGF23 assays and urges clinicians to be aware that cFGF23 concentrations do not necessarily reflect iFGF23 concentrations and that alternative causes for its elevation should be considered (eg, iron deficiency). © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC. on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Ariadne Bosman
- Department of Internal MedicineErasmus MC, University Medical CenterRotterdamThe Netherlands
| | - Danielle MA Ratsma
- Department of Internal MedicineErasmus MC, University Medical CenterRotterdamThe Netherlands
| | - Bram CJ van der Eerden
- Department of Internal MedicineErasmus MC, University Medical CenterRotterdamThe Netherlands
| | - M Carola Zillikens
- Department of Internal MedicineErasmus MC, University Medical CenterRotterdamThe Netherlands
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10
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Li X, Lozovatsky L, Tommasini SM, Fretz J, Finberg KE. Bone marrow sinusoidal endothelial cells are a site of Fgf23 upregulation in a mouse model of iron deficiency anemia. Blood Adv 2023; 7:5156-5171. [PMID: 37417950 PMCID: PMC10480544 DOI: 10.1182/bloodadvances.2022009524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 06/16/2023] [Accepted: 07/05/2023] [Indexed: 07/08/2023] Open
Abstract
Iron deficiency is a potent stimulator of fibroblast growth factor 23 (FGF23), a hormonal regulator of phosphate and vitamin D metabolism, that is classically thought to be produced by bone-embedded osteocytes. Here, we show that iron-deficient transmembrane serine protease 6 knockout (Tmprss6-/-) mice exhibit elevated circulating FGF23 and Fgf23 messenger RNA (mRNA) upregulation in the bone marrow (BM) but not the cortical bone. To clarify sites of Fgf23 promoter activity in Tmprss6-/- mice, we introduced a heterozygous enhanced green fluorescent protein (eGFP) reporter allele at the endogenous Fgf23 locus. Heterozygous Fgf23 disruption did not alter the severity of systemic iron deficiency or anemia in the Tmprss6-/- mice. Tmprss6-/-Fgf23+/eGFP mice showed green fluorescence in the vascular regions of BM sections and showed a subset of BM endothelial cells that were GFPbright by flow cytometry. Mining of transcriptomic data sets from mice with normal iron balance revealed higher Fgf23 mRNA in BM sinusoidal endothelial cells (BM-SECs) than that in other BM endothelial cell populations. Anti-GFP immunohistochemistry of fixed BM sections from Tmprss6-/-Fgf23+/eGFP mice revealed GFP expression in BM-SECs, which was more intense than in nonanemic controls. In addition, in mice with intact Tmprss6 alleles, Fgf23-eGFP reporter expression increased in BM-SECs following large-volume phlebotomy and also following erythropoietin treatment both ex vivo and in vivo. Collectively, our results identified BM-SECs as a novel site for Fgf23 upregulation in both acute and chronic anemia. Given the elevated serum erythropoietin in both anemic models, our findings raise the possibility that erythropoietin may act directly on BM-SECs to promote FGF23 production during anemia.
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Affiliation(s)
- Xiuqi Li
- Department of Pathology, Yale School of Medicine, New Haven, CT
| | | | - Steven M. Tommasini
- Department of Orthopaedics & Rehabilitation, Yale School of Medicine, New Haven, CT
| | - Jackie Fretz
- Department of Orthopaedics & Rehabilitation, Yale School of Medicine, New Haven, CT
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11
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Gedaj A, Zukowska D, Porebska N, Pozniak M, Krzyscik M, Czyrek A, Krowarsch D, Zakrzewska M, Otlewski J, Opalinski L. Short report galectins use N-glycans of FGFs to capture growth factors at the cell surface and fine-tune their signaling. Cell Commun Signal 2023; 21:122. [PMID: 37231412 DOI: 10.1186/s12964-023-01144-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 04/23/2023] [Indexed: 05/27/2023] Open
Abstract
Fibroblast growth factors (FGFs) and their receptors (FGFRs) constitute complex signaling hubs that are crucial for the development and homeostasis of the human body. Most of FGFs are released by cells using the conventional secretory pathway and are N-glycosylated, yet the role of FGFs glycosylation is largely unknown. Here, we identify N-glycans of FGFs as binding sites for a specific set of extracellular lectins, galectins - 1, -3, -7 and - 8. We demonstrate that galectins attract N-glycosylated FGF4 to the cell surface, forming a reservoir of the growth factor in the extracellular matrix. Furthermore, we show that distinct galectins differentially modulate FGF4 signaling and FGF4-dependent cellular processes. Using engineered variants of galectins with altered valency we demonstrate that multivalency of galectins is critical for the adjustment of FGF4 activity. Summarizing, our data reveal a novel regulatory module within FGF signaling, in which the glyco-code in FGFs provides previously unanticipated information differentially deciphered by multivalent galectins, affecting signal transduction and cell physiology. Video Abstract.
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Affiliation(s)
- Aleksandra Gedaj
- Faculty of Biotechnology, Department of Protein Engineering, University of Wroclaw, Joliot-Curie 14a, 50-383, Wroclaw, Poland
| | - Dominika Zukowska
- Faculty of Biotechnology, Department of Protein Engineering, University of Wroclaw, Joliot-Curie 14a, 50-383, Wroclaw, Poland
| | - Natalia Porebska
- Faculty of Biotechnology, Department of Protein Engineering, University of Wroclaw, Joliot-Curie 14a, 50-383, Wroclaw, Poland
| | - Marta Pozniak
- Faculty of Biotechnology, Department of Protein Engineering, University of Wroclaw, Joliot-Curie 14a, 50-383, Wroclaw, Poland
| | - Mateusz Krzyscik
- Faculty of Biotechnology, Department of Protein Engineering, University of Wroclaw, Joliot-Curie 14a, 50-383, Wroclaw, Poland
| | - Aleksandra Czyrek
- Faculty of Biotechnology, Department of Protein Biotechnology, University of Wroclaw, Joliot-Curie 14a, 50-383, Wroclaw, Poland
| | - Daniel Krowarsch
- Faculty of Biotechnology, Department of Protein Biotechnology, University of Wroclaw, Joliot-Curie 14a, 50-383, Wroclaw, Poland
| | - Malgorzata Zakrzewska
- Faculty of Biotechnology, Department of Protein Engineering, University of Wroclaw, Joliot-Curie 14a, 50-383, Wroclaw, Poland
| | - Jacek Otlewski
- Faculty of Biotechnology, Department of Protein Engineering, University of Wroclaw, Joliot-Curie 14a, 50-383, Wroclaw, Poland
| | - Lukasz Opalinski
- Faculty of Biotechnology, Department of Protein Engineering, University of Wroclaw, Joliot-Curie 14a, 50-383, Wroclaw, Poland.
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12
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Sun T, Yu X. FGF23 Actions in CKD-MBD and other Organs During CKD. Curr Med Chem 2023; 30:841-856. [PMID: 35761503 DOI: 10.2174/0929867329666220627122733] [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: 12/13/2021] [Revised: 03/26/2022] [Accepted: 04/12/2022] [Indexed: 02/08/2023]
Abstract
Fibroblast growth factor 23 (FGF23) is a new endocrine product discovered in the past decade. In addition to being related to bone diseases, it has also been found to be related to kidney metabolism and parathyroid metabolism, especially as a biomarker and a key factor to be used in kidney diseases. FGF23 is upregulated as early as the second and third stages of chronic kidney disease (CKD) in response to relative phosphorus overload. The early rise of FGF23 has a protective effect on the body and is essential for maintaining phosphate balance. However, with the decline in renal function, eGFR (estimated glomerular filtration rate) declines, and the phosphorus excretion effect caused by FGF23 is weakened. It eventually leads to a variety of complications, such as bone disease (Chronic Kidney Disease-Mineral and Bone Metabolism Disorder), vascular calcification (VC), and more. Monoclonal antibodies against FGF23 are currently used to treat genetic diseases with increased FGF23. CKD is also a state of increased FGF23. This article reviews the current role of FGF23 in CKD and discusses the crosstalk between various organs under CKD conditions and FGF23. Studying the effect of hyperphosphatemia on different organs of CKD is important. The prospect of FGF23 for therapy is also discussed.
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Affiliation(s)
- Ting Sun
- Laboratory of Endocrinology and Metabolism, Department of Endocrinology and Metabolism, Rare Disease Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Xijie Yu
- Laboratory of Endocrinology and Metabolism, Department of Endocrinology and Metabolism, Rare Disease Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu 610041, China
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13
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Latic N, Erben RG. Interaction of Vitamin D with Peptide Hormones with Emphasis on Parathyroid Hormone, FGF23, and the Renin-Angiotensin-Aldosterone System. Nutrients 2022; 14:nu14235186. [PMID: 36501215 PMCID: PMC9736617 DOI: 10.3390/nu14235186] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 11/29/2022] [Accepted: 12/01/2022] [Indexed: 12/12/2022] Open
Abstract
The seminal discoveries that parathyroid hormone (PTH) and fibroblast growth factor 23 (FGF23) are major endocrine regulators of vitamin D metabolism led to a significant improvement in our understanding of the pivotal roles of peptide hormones and small proteohormones in the crosstalk between different organs, regulating vitamin D metabolism. The interaction of vitamin D, FGF23 and PTH in the kidney is essential for maintaining mineral homeostasis. The proteohormone FGF23 is mainly secreted from osteoblasts and osteoclasts in the bone. FGF23 acts on proximal renal tubules to decrease production of the active form of vitamin D (1,25(OH)2D) by downregulating transcription of 1α-hydroxylase (CYP27B1), and by activating transcription of the key enzyme responsible for vitamin D degradation, 24-hydroxylase (CYP24A1). Conversely, the peptide hormone PTH stimulates 1,25(OH)2D renal production by upregulating the expression of 1α-hydroxylase and downregulating that of 24-hydroxylase. The circulating concentration of 1,25(OH)2D is a positive regulator of FGF23 secretion in the bone, and a negative regulator of PTH secretion from the parathyroid gland, forming feedback loops between kidney and bone, and between kidney and parathyroid gland, respectively. In recent years, it has become clear that vitamin D signaling has important functions beyond mineral metabolism. Observation of seasonal variations in blood pressure and the subsequent identification of vitamin D receptor (VDR) and 1α-hydroxylase in non-renal tissues such as cardiomyocytes, endothelial and smooth muscle cells, suggested that vitamin D may play a role in maintaining cardiovascular health. Indeed, observational studies in humans have found an association between vitamin D deficiency and hypertension, left ventricular hypertrophy and heart failure, and experimental studies provided strong evidence for a role of vitamin D signaling in the regulation of cardiovascular function. One of the proposed mechanisms of action of vitamin D is that it functions as a negative regulator of the renin-angiotensin-aldosterone system (RAAS). This finding established a novel link between vitamin D and RAAS that was unexplored until then. During recent years, major progress has been made towards a more complete understanding of the mechanisms by which FGF23, PTH, and RAAS regulate vitamin D metabolism, especially at the genomic level. However, there are still major gaps in our knowledge that need to be filled by future research. The purpose of this review is to highlight our current understanding of the molecular mechanisms underlying the interaction between vitamin D, FGF23, PTH, and RAAS, and to discuss the role of these mechanisms in physiology and pathophysiology.
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14
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Fratzl-Zelman N, Hartmann MA, Gamsjaeger S, Rokidi S, Paschalis EP, Blouin S, Zwerina J. Bone Matrix Mineralization and Response to Burosumab in Adult Patients With X-Linked Hypophosphatemia: Results From the Phase 3, Single-Arm International Trial. J Bone Miner Res 2022; 37:1665-1678. [PMID: 35775373 DOI: 10.1002/jbmr.4641] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 05/20/2022] [Accepted: 06/25/2022] [Indexed: 11/06/2022]
Abstract
X-linked hypophosphatemia (XLH) is characterized by excess fibroblast growth factor 23 (FGF23) secretion, renal phosphate wasting, and low 1,25(OH)2 D3 . Adult patients present with osteomalacia, hypomineralized periosteocytic lesions, bone fragility, and pain. Burosumab is a fully human monoclonal FGF23 antibody approved for XLH treatment. UX023-CL304 was an open-label, phase 3 study investigating the effects of burosumab on osteomalacia in adults with XLH, who remained untreated at least 2 years prior enrollment. Here, we present the effect of burosumab on bone material properties. We analyzed transiliac bone biopsy samples from 11 individuals before and after 48 weeks of subcutaneous burosumab treatment (1.0 mg/kg administered every 4 weeks). We used quantitative backscattered electron imaging (qBEI) and Fourier transform infrared imaging (FTIRI) to assess bone mineralization density distribution (BMDD), mineralized bone volume, properties of the organic matrix, and size of periosteocytic lesions. The outcomes were compared with reference values from healthy adults and with four XLH patients either untreated or treated by conventional therapy. Prior to burosumab, the average mineralization in cancellous bone was lower than in healthy reference. CaLow, the fraction of lowly mineralized matrix, and CaHigh, the fraction of highly mineralized matrix, were both elevated resulting in a broad heterogeneity in mineralization (CaWidth). Burosumab resulted in a decrease of CaHigh toward normal range, whereas CaLow and CaWidth remained elevated. The mineralized bone volume was notably increased (+35.9%). The size of the periosteocytic lesions was variable but lower than in untreated XLH patients. FTIRI indicated decreased enzymatic collagen crosslink ratio heterogeneity. In summary, matrix mineralization in XLH is very heterogeneous. Highly mineralized regions represent old bone packets, probably protected from osteoclastic resorption by osteoid seams. The concomitant decrease of highly mineralized matrix, persistence of lowly mineralized matrix, and increase in mineralized bone volume after burosumab suggest a boost in mineralization of preexisting unmineralized or very lowly mineralized matrix, providing a potential explanation for previously observed improved osteomalacia. © 2022 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Nadja Fratzl-Zelman
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Med Department Hanusch Hospital, Vienna, Austria.,Vienna Bone and Growth Center, Vienna, Austria
| | - Markus A Hartmann
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Med Department Hanusch Hospital, Vienna, Austria.,Vienna Bone and Growth Center, Vienna, Austria
| | - Sonja Gamsjaeger
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Med Department Hanusch Hospital, Vienna, Austria
| | - Stamatia Rokidi
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Med Department Hanusch Hospital, Vienna, Austria
| | - Eleftherios P Paschalis
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Med Department Hanusch Hospital, Vienna, Austria.,Vienna Bone and Growth Center, Vienna, Austria
| | - Stéphane Blouin
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Med Department Hanusch Hospital, Vienna, Austria.,Vienna Bone and Growth Center, Vienna, Austria
| | - Jochen Zwerina
- Ludwig Boltzmann Institute of Osteology at Hanusch Hospital of OEGK and AUVA Trauma Centre Meidling, 1st Med Department Hanusch Hospital, Vienna, Austria.,Vienna Bone and Growth Center, Vienna, Austria
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15
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Ornitz DM, Itoh N. New developments in the biology of fibroblast growth factors. WIREs Mech Dis 2022; 14:e1549. [PMID: 35142107 PMCID: PMC10115509 DOI: 10.1002/wsbm.1549] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 11/08/2021] [Accepted: 11/09/2021] [Indexed: 01/28/2023]
Abstract
The fibroblast growth factor (FGF) family is composed of 18 secreted signaling proteins consisting of canonical FGFs and endocrine FGFs that activate four receptor tyrosine kinases (FGFRs 1-4) and four intracellular proteins (intracellular FGFs or iFGFs) that primarily function to regulate the activity of voltage-gated sodium channels and other molecules. The canonical FGFs, endocrine FGFs, and iFGFs have been reviewed extensively by us and others. In this review, we briefly summarize past reviews and then focus on new developments in the FGF field since our last review in 2015. Some of the highlights in the past 6 years include the use of optogenetic tools, viral vectors, and inducible transgenes to experimentally modulate FGF signaling, the clinical use of small molecule FGFR inhibitors, an expanded understanding of endocrine FGF signaling, functions for FGF signaling in stem cell pluripotency and differentiation, roles for FGF signaling in tissue homeostasis and regeneration, a continuing elaboration of mechanisms of FGF signaling in development, and an expanding appreciation of roles for FGF signaling in neuropsychiatric diseases. This article is categorized under: Cardiovascular Diseases > Molecular and Cellular Physiology Neurological Diseases > Molecular and Cellular Physiology Congenital Diseases > Stem Cells and Development Cancer > Stem Cells and Development.
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Affiliation(s)
- David M Ornitz
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Nobuyuki Itoh
- Kyoto University Graduate School of Pharmaceutical Sciences, Sakyo, Kyoto, Japan
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16
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Kang M, Chen J, Liu L, Xue C, Tang X, Lv J, Fu L, Mei C, Mao Z, Liu Y, Dai B. In-center Nocturnal Hemodialysis Reduced the Circulating FGF23, Left Ventricular Hypertrophy, and All-Cause Mortality: A Retrospective Cohort Study. Front Med (Lausanne) 2022; 9:912764. [PMID: 35801203 PMCID: PMC9253468 DOI: 10.3389/fmed.2022.912764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 05/20/2022] [Indexed: 11/13/2022] Open
Abstract
Fibroblast growth factor 23(FGF23) is the most important biomarker and pathogenic factor in Chronic Kidney Disease–Mineral and Bone Disorder (CKD–MBD). In the moderate and severe stages of chronic renal failure, abnormally elevated circulating FGF23 can lead to some complications, including myocardial hypertrophy, which is positively correlated with all-cause mortality. However, the circulating FGF23 level of different hemodialysis modalities, the underlying essential regulatory factors, and potential clinical benefits remain to be elucidated. In this retrospective cohort study, 90 in-center nocturnal hemodialysis (INHD) and 90 matched conventional hemodialysis (CHD) patients were enrolled. The complete blood count, intact FGF23(iFGF23), calcium, phosphorus, PTH, and other biochemical and echocardiographic parameters of INHD and CHD patients were collected and analyzed at 1-year follow-up. The all-cause mortality was recorded during the 7-year follow-up. Furthermore, the regulatory factors of iFGF23 and its association with echocardiographic parameters and mortality were investigated by multivariate regression. The levels of iFGF23 and serum phosphate in patients undergoing INHD were significantly lower than those in patients undergoing CHD. The left ventricular volume index (LVMI) in patients with INHD was significantly attenuated and positively correlated with the drop of serum iFGF23. The INHD group had reduced all-cause mortality compared to the CHD group. Multivariate analysis showed that iFGF23 was positively correlated with serum calcium, serum phosphorus, and calcium-phosphate product. The calcium-phosphate product is an independent determining factor of serum iFGF23. Compared with the CHD group, the INHD group presented with a significantly reduced circulating iFGF23 level, which was closely associated with attenuation of left ventricular hypertrophy, but INHD reduced all-cause mortality in an FGF23 independent manner.
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Affiliation(s)
- Meizi Kang
- Division of Nephrology, The Second Affiliated Hospital of Nantong University, Nantong, China
- Division of Nephrology, Kidney Institute of People's Liberation Army of China, Shanghai Changzheng Hospital, Naval Medical University, Shanghai, China
| | - Jing Chen
- Division of Nephrology, Kidney Institute of People's Liberation Army of China, Shanghai Changzheng Hospital, Naval Medical University, Shanghai, China
| | - Lingling Liu
- Division of Nephrology, Kidney Institute of People's Liberation Army of China, Shanghai Changzheng Hospital, Naval Medical University, Shanghai, China
| | - Cheng Xue
- Division of Nephrology, Kidney Institute of People's Liberation Army of China, Shanghai Changzheng Hospital, Naval Medical University, Shanghai, China
| | - Xiaojing Tang
- Division of Nephrology, Kidney Institute of People's Liberation Army of China, Shanghai Changzheng Hospital, Naval Medical University, Shanghai, China
| | - Jiayi Lv
- Division of Nephrology, Kidney Institute of People's Liberation Army of China, Shanghai Changzheng Hospital, Naval Medical University, Shanghai, China
| | - Lili Fu
- Division of Nephrology, Kidney Institute of People's Liberation Army of China, Shanghai Changzheng Hospital, Naval Medical University, Shanghai, China
| | - Changlin Mei
- Division of Nephrology, Kidney Institute of People's Liberation Army of China, Shanghai Changzheng Hospital, Naval Medical University, Shanghai, China
| | - Zhiguo Mao
- Division of Nephrology, Kidney Institute of People's Liberation Army of China, Shanghai Changzheng Hospital, Naval Medical University, Shanghai, China
| | - Yawei Liu
- Division of Nephrology, Kidney Institute of People's Liberation Army of China, Shanghai Changzheng Hospital, Naval Medical University, Shanghai, China
- Department of Internal Medicine, Shanghai Changzheng Hospital, Naval Medical University, Shanghai, China
- *Correspondence: Bing Dai
| | - Bing Dai
- Division of Nephrology, Kidney Institute of People's Liberation Army of China, Shanghai Changzheng Hospital, Naval Medical University, Shanghai, China
- Yawei Liu
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Vaculik J, Wenchich L, Bobelyak M, Pavelka K, Stepan JJ. A decrease in serum 1,25(OH) 2D after elective hip replacement and during bone healing is associated with changes in serum iron and plasma FGF23. J Endocrinol Invest 2022; 45:1039-1044. [PMID: 35079976 DOI: 10.1007/s40618-022-01746-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 01/13/2022] [Indexed: 10/19/2022]
Abstract
OBJECTIVE Although calcitriol is essential for bone healing, its serum concentrations are low after hip surgery, and they continue to decline during bone healing. This study aimed to test the hypothesis of an association of changes in calcitriol production with the status of fibroblast growth factor 23 (FGF23) and iron deficiency after elective hip replacement for coxarthrosis. METHODS In this prospective study, we measured the biomarkers of 17 patients undergoing elective hip replacement on admission, on the first day after surgery, and at the regular check-up after 48 ± 8 days. The serum concentrations of 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, transferrin, ferritin, parathyroid hormone, intact plasma FGF23 (iFGF23) and C-terminal FGF23 (cFGF23) were determined. RESULTS In our patients who underwent elective hip replacement, significant correlations existed between the percent change in the conversion rate of 25(OH)D to 1,25(OH)2D, plasma intact to C-terminal FGF23 ratio, and serum iron. CONCLUSIONS The production of calcitriol is compromised after elective hip replacement surgery, leading to reduced levels of active vitamin D in the serum. Significant correlations between the percent change in the conversion rate of 25(OH)D to 1,25(OH)2D, plasma intact to C-terminal FGF23 ratio, and serum iron on the first day as well as 7 weeks after surgery could inspire future studies to determine whether and how calcitriol deficiency should be corrected, especially in fracture cases.
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Affiliation(s)
- J Vaculik
- Orthopedic Department, Bulovka Hospital, Prague, Czech Republic
- Third Faculty of Medicine, Charles University, Prague, Czech Republic
- Orthopedic Department, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - L Wenchich
- Institute of Rheumatology, Prague, Czech Republic
| | - M Bobelyak
- Orthopedic Department, Bulovka Hospital, Prague, Czech Republic
- Third Faculty of Medicine, Charles University, Prague, Czech Republic
| | - K Pavelka
- Institute of Rheumatology, Prague, Czech Republic
- Department of Rheumatology, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - J J Stepan
- Institute of Rheumatology, Prague, Czech Republic.
- Department of Rheumatology, First Faculty of Medicine, Charles University, Prague, Czech Republic.
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Xu T, Tao X, Zhang Z, Yue H. Clinical and genetic characteristics of 29 Chinese patients with X-linked hypophosphatemia. Front Endocrinol (Lausanne) 2022; 13:956646. [PMID: 36060934 PMCID: PMC9437435 DOI: 10.3389/fendo.2022.956646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 08/02/2022] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVE The aim of this study was to fully describe the clinical and genetic characteristics, including clinical manifestations, intact fibroblast growth factor 23 (iFGF23) levels, and presence of PHEX gene mutations, of 22 and 7 patients with familial and sporadic X-linked dominant hypophosphatemia (XLH), respectively. METHODS Demographic data, clinical features, biochemical indicators, and imaging data of 29 patients were collected. All 22 exons and exon-intron boundaries of the PHEX gene were amplified by polymerase chain reaction (PCR) and directly sequenced. The serum level of iFGF23 was measured in 15 of the patients. RESULTS Twenty-nine patients (male/female: 13:16, juvenile/adult: 15:14) with XLH were included. The main symptoms were bowed lower extremities (89.7%), abnormal gait (89.7%), and short stature/growth retardation (78.6%). Hypophosphatemia with a high alkaline phosphatase level was the main biochemical feature and the median value of serum iFGF23 was 55.7 pg/ml (reference range: 16.1-42.2 pg/ml). Eight novel mutations in the PHEX gene were identified by Sanger sequencing, including two missense mutations (p. Gln682Leu and p. Phe312Ser), two deletions (c.350_356del and c.755_761del), one insertion (c.1985_1986insTGAC), and three splice mutations (c.1700+5G>C, c.1966-1G>T, and c.350-14_350-1del). Additionally, the recurrence rate after the first orthopedic surgery was 77.8% (7/9), and five of them had their first surgery before puberty. CONCLUSION Our study expanded the clinical phenotypes and gene mutation spectrum of XLH and provided a reference for the optimal timing of orthopedic surgeries.
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Affiliation(s)
| | | | | | - Hua Yue
- *Correspondence: Hua Yue, ; Zhenlin Zhang,
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19
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Lafage-Proust MH. What are the benefits of the anti-FGF23 antibody burosumab on the manifestations of X-linked hypophosphatemia in adults in comparison with conventional therapy? A review. THERAPEUTIC ADVANCES IN RARE DISEASE 2022; 3:26330040221074702. [PMID: 37180412 PMCID: PMC10032432 DOI: 10.1177/26330040221074702] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 01/03/2022] [Indexed: 05/16/2023]
Abstract
X-linked hypophosphatemia (XLH) is a genetic disease mostly related to PHEX gene mutations which increases FGF23 serum levels, leading to hypophosphatemia and osteomalacia in adults, while affected children, in addition, develop rickets. Most of adults with XLH suffer from reduced quality of life and physical disability due to chronic bone and joint pain related to limb deformities, early osteoarthritis, delayed-healing of insufficiency fractures, and enthesopathies. Dental infections, muscle dysfunction, and deafness are also frequent. The current treatment consists of 2-5 times daily oral administration of phosphate combined to active vitamin D, often badly tolerated with immediate digestive side effects, responsible for poor compliance. In the long term, it may induce nephrocalcinosis and hyperparathyroidism. Burosumab, an anti-FGF23 blocking antibody, was approved for treating children with XLH in many countries. A randomized 24-week-long placebo-controlled trial, followed by an open-label period of equal duration was conducted in 134 XLH adults treated with 1 mg/kg burosumab/4 weeks. During burosumab treatment, 94% of the patients normalized serum phosphate values versus 7% in the placebo group. Fracture healing was increased 16.7 times compared with placebo-treated patients. All pain and disability tests improved significantly in a time-dependent manner. Burosumab for 48 weeks improved histological lesions of osteomalacia in a single-arm longitudinal study analyzing paired bone biopsies. Another single-arm, open-label study investigated the long-term safety and efficacy of burosumab in 20 adult patients followed for 3.2 years. Burosumab was beneficial on pain and disability scores and on bone remodeling markers. No major side effects especially no hyperphosphatemic episodes were reported. Overall, the benefit/risk ratio of burosumab is positive in adult patients with clinical and/or biological complications of XLH. Burosumab corrects hypophosphatemia, promotes fracture healing, and induces a modest but significant effect on XLH-induced subjective pain and disability symptoms. Plain language title and summary Effects of conventional treatment and burosumab in adults with X-linked hypophosphatemia.X-linked hypophosphatemia (XLH) is a disease of genetic origin that affects mineralized tissues (skeleton and teeth) and impairs muscle function. It induces a decrease in blood phosphate levels. This leads to under mineralization of bones and insufficiency fractures that heal slowly, associated with poor dental health characterized by spontaneous dental abscesses. Adults with XLH suffer from chronic pain and limb deformities that alter their quality of life. They are currently treated with daily administration of vitamin D and several daily doses of phosphate. This treatment may induce parathyroid gland dysfunction and mineral deposits in the kidney. If not tightly monitored, these side effects may lead to tertiary hyperparathyroidism and the need for parathyroid gland surgery, or to nephrocalcinosis which may proceed to chronic kidney disease. Burosumab is an antibody that blocks the action of FGF23 the factor that circulates in excess in blood and is responsible for phosphate renal leak in XLH. Three studies demonstrated that burosumab, injected every 4 weeks, is efficient and safe for treating adults with XLH.
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Abstract
Apart from its phosphaturic action, the bone-derived hormone fibroblast growth factor-23 (FGF23) is also an essential regulator of vitamin D metabolism. The main target organ of FGF23 is the kidney, where FGF23 suppresses transcription of the key enzyme in vitamin D hormone (1,25(OH)2D) activation, 1α-hydroxylase, and activates transcription of the key enzyme responsible for vitamin D degradation, 24-hydroxylase, in proximal renal tubules. The circulating concentration of 1,25(OH)2D is a positive regulator of FGF23 secretion in bone, forming a feedback loop between kidney and bone. The importance of FGF23 as regulator of vitamin D metabolism is underscored by the fact that in the absence of FGF23 signaling, the tight control of renal 1α-hydroxylase fails, resulting in overproduction of 1,25(OH)2D in mice and men. During recent years, big strides have been made toward a more complete understanding of the mechanisms underlying the FGF23-mediated regulation of vitamin D metabolism, especially at the genomic level. However, there are still major gaps in our knowledge that need to be filled by future research. Importantly, the intracellular signaling cascades downstream of FGF receptors regulating transcription of 1α-hydroxylase and 24-hydroxylase in proximal renal tubules still remain unresolved. The purpose of this review is to highlight our current understanding of the molecular mechanisms underlying the regulation of vitamin D metabolism by FGF23, and to discuss the role of these mechanisms in physiology and pathophysiology. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC. on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Nejla Latic
- Department of Biomedical Sciences University of Veterinary Medicine Vienna Austria
| | - Reinhold G Erben
- Department of Biomedical Sciences University of Veterinary Medicine Vienna Austria
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21
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Papadopoulos KI, Sutheesophon W, Manipalviratn S, Aw TC. Age and genotype dependent erythropoietin protection in COVID-19. World J Stem Cells 2021; 13:1513-1529. [PMID: 34786155 PMCID: PMC8567454 DOI: 10.4252/wjsc.v13.i10.1513] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 06/23/2021] [Accepted: 09/19/2021] [Indexed: 02/06/2023] Open
Abstract
Erythropoietin (EPO) is the main mediator of erythropoiesis and an important tissue protective hormone that appears to mediate an ancestral neuroprotective innate immune response mechanism at an early age. When the young brain is threatened-prematurity, neonatal hyperbilirubinemia, malaria- EPO is hyper-secreted disproportionately to any concurrent anemic stimuli. Under eons of severe malarial selection pressure, neuroprotective EPO augmenting genetic determinants such as the various hemoglobinopathies, and the angiotensin converting enzyme (ACE) I/D polymorphism, have been positively selected. When malarial and other cerebral threats abate and the young child survives to adulthood, EPO subsides. Sustained high ACE and angiotensin II (Ang II) levels through the ACE D allele in adulthood may then become detrimental as witnessed by epidemiological studies. The ubiquitous renin angiotensin system (RAS) influences the α-klotho/fibroblast growth factor 23 (FGF23) circuitry, and both are interconnected with EPO. Here we propose that at a young age, EPO augmenting genetic determinants through ACE D allele elevated Ang II levels in some or HbE/beta thalassemia in others would increase EPO levels and shield against coronavirus disease 2019, akin to protection from malaria and dengue fever. Human evolution may use ACE2 as a “bait” for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) to gain cellular entry in order to trigger an ACE/ACE2 imbalance and stimulate EPO hypersecretion using tissue RAS, uncoupled from hemoglobin levels. In subjects without EPO augmenting genetic determinants at any age, ACE2 binding and internalization upon SARS-CoV-2 entry would trigger an ACE/ACE2 imbalance, and Ang II oversecretion leading to protective EPO stimulation. In children, low nasal ACE2 Levels would beneficially augment this imbalance, especially for those without protective genetic determinants. On the other hand, in predisposed adults with the ACE D allele, ACE/ACE2 imbalance, may lead to uncontrolled RAS overactivity and an Ang II induced proinflammatory state and immune dysregulation, with interleukin 6 (IL-6), plasminogen activator inhibitor, and FGF23 elevations. IL-6 induced EPO suppression, aggravated through co-morbidities such as hypertension, diabetes, obesity, and RAS pharmacological interventions may potentially lead to acute respiratory distress syndrome, cytokine storm and/or autoimmunity. HbE/beta thalassemia carriers would enjoy protection at any age as their EPO stimulation is uncoupled from the RAS system. The timely use of rhEPO, EPO analogs, acetylsalicylic acid, bioactive lipids, or FGF23 antagonists in genetically predisposed individuals may counteract those detrimental effects.
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Affiliation(s)
| | | | - Somjate Manipalviratn
- Department of Reproductive Endocrinology, Jetanin Institute for Assisted Reproduction, Bangkok 10330, Thailand
| | - Tar-Choon Aw
- Department of Laboratory Medicine, Changi General Hospital, Singapore 529889, Singapore
- Department of Medicine, National University of Singapore, Singapore 119228, Singapore
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22
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Leifheit-Nestler M, Haffner D. How FGF23 shapes multiple organs in chronic kidney disease. Mol Cell Pediatr 2021; 8:12. [PMID: 34536161 PMCID: PMC8449753 DOI: 10.1186/s40348-021-00123-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 09/07/2021] [Indexed: 12/13/2022] Open
Abstract
Chronic kidney disease (CKD) is associated with distinct alterations in mineral metabolism in children and adults resulting in multiple organ dysfunctions. Children with advanced CKD often suffer from impaired bone mineralization, bone deformities and fractures, growth failure, muscle weakness, and vascular and soft tissue calcification, a complex which was recently termed CKD-mineral and bone disorder (CKD-MBD). The latter is a major contributor to the enhanced cardiovascular disease comorbidity and mortality in these patients. Elevated circulating levels of the endocrine-acting phosphaturic hormone fibroblast growth factor (FGF) 23 are the first detectable alteration of mineral metabolism and thus CKD-MBD. FGF23 is expressed and secreted from osteocytes and osteoblasts and rises, most likely due to increased phosphate load, progressively as kidney function declines in order to maintain phosphate homeostasis. Although not measured in clinical routine yet, CKD-mediated increased circulating levels of FGF23 in children are associated with pathological cardiac remodeling, vascular alterations, and increased cognitive risk. Clinical and experimental studies addressing other FGF23-mediated complications of kidney failure, such as hypertension and impaired bone mineralization, show partly conflicting results, and the causal relationships are not always entirely clear. This short review summarizes regulators of FGF23 synthesis altered in CKD and the main CKD-mediated organ dysfunctions related to high FGF23 levels.
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Affiliation(s)
- Maren Leifheit-Nestler
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Pediatric Research Center, Hannover Medical School Children's Hospital, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
| | - Dieter Haffner
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Pediatric Research Center, Hannover Medical School Children's Hospital, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
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