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Liu T, Wen H, Li H, Xu H, Xiao N, Liu R, Chen L, Sun Y, Song L, Bai C, Ge J, Zhang Y, Chen J. Oleic Acid Attenuates Ang II (Angiotensin II)-Induced Cardiac Remodeling by Inhibiting FGF23 (Fibroblast Growth Factor 23) Expression in Mice. Hypertension 2020; 75:680-692. [DOI: 10.1161/hypertensionaha.119.14167] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Plasma metabolic profiles were compared between patients with hypertension with and without left ventricular hypertrophy and significantly decreased oleic acid (OA) levels were observed in the peripheral blood of patients with hypertension with left ventricular hypertrophy. We sought to determine the effect and underlying mechanisms of OA on cardiac remodeling. In vitro studies with isolated neonatal mouse cardiomyocytes and cardiac fibroblasts revealed that OA significantly attenuated Ang II (angiotensin II)-induced cardiomyocyte growth and cardiac fibroblast collagen expression. In vivo, cardiac function, hypertrophic growth of cardiomyocytes, and fibrosis were analyzed after an Ang II (1000 ng/kg/minute) pump was implanted for 14 days. We found that OA could significantly prevent Ang II-induced cardiac remodeling in mice. RNA sequencing served as a gene expression roadmap highlighting gene expression changes in the hearts of Ang II-induced mice and OA-treated mice. The results revealed that FGF23 (fibroblast growth factor 23) expression was significantly upregulated in mouse hearts in response to Ang II infusion, which was significantly suppressed in the hearts of OA-treated mice. Furthermore, overexpression of FGF23 in the heart by injection of an AAV-9 vector aggravated Ang II-induced cardiac remodeling and impaired the protective effect of OA on cardiac remodeling. Further study found that OA could suppress Ang II-induced FGF23 expression by inhibiting the translocation of Nurr1 (nuclear receptor–related 1 protein) from the cytoplasm to the nucleus. Our findings suggest a novel role of OA in preventing Ang II-induced cardiac remodeling via suppression of FGF23 expression.
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Affiliation(s)
- Tianlong Liu
- From the State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China (T.L., H.W., H.L., N.X., Y.S., L.S., C.B., J.G., Y.Z.)
| | - Hongyan Wen
- From the State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China (T.L., H.W., H.L., N.X., Y.S., L.S., C.B., J.G., Y.Z.)
| | - Hao Li
- From the State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China (T.L., H.W., H.L., N.X., Y.S., L.S., C.B., J.G., Y.Z.)
| | | | - Ning Xiao
- From the State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China (T.L., H.W., H.L., N.X., Y.S., L.S., C.B., J.G., Y.Z.)
| | | | - Luonan Chen
- Key Laboratory of Systems Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, China (L.C.)
| | - Yingying Sun
- From the State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China (T.L., H.W., H.L., N.X., Y.S., L.S., C.B., J.G., Y.Z.)
| | - Li Song
- From the State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China (T.L., H.W., H.L., N.X., Y.S., L.S., C.B., J.G., Y.Z.)
| | - Congxia Bai
- From the State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China (T.L., H.W., H.L., N.X., Y.S., L.S., C.B., J.G., Y.Z.)
| | - Jing Ge
- From the State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China (T.L., H.W., H.L., N.X., Y.S., L.S., C.B., J.G., Y.Z.)
| | - Yinhui Zhang
- From the State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China (T.L., H.W., H.L., N.X., Y.S., L.S., C.B., J.G., Y.Z.)
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52
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Wang T, Yu X, He C. Pro-inflammatory Cytokines: Cellular and Molecular Drug Targets for Glucocorticoid-induced-osteoporosis via Osteocyte. Curr Drug Targets 2020; 20:1-15. [PMID: 29618305 DOI: 10.2174/1389450119666180405094046] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 03/11/2018] [Accepted: 03/21/2018] [Indexed: 02/08/2023]
Abstract
Glucocorticoids are widely used to treat varieties of allergic and autoimmune diseases, however, long-term application results in glucocorticoid-induced osteoporosis (GIOP). Inflammatory cytokines: tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) play important regulatory roles in bone metabolism, but their roles in GIOP remain largely unknown. Osteocytes can modulate the formation and function of both osteoblasts and osteoclasts, directly via gap junctions, or indirectly by transferring molecule signaling. Apoptotic osteocytes release RANKL, HMGB1 and pro-inflammatory cytokines to stimulate osteoclastogenesis. Moreover, osteocytes can secrete FGF23 to regulate bone metabolism. Exposure to high levels of GCs can drive osteocyte apoptosis and influence gap junctions, leading to bone loss. GCs treatment is regarded to produce more FGF23 to inhibit bone mineralization. GCs also disrupt the vascular to decrease osteocyte feasibility and mineral appositional rate, resulting in a decline in bone strength. Apoptotic bodies from osteocytes induced by GCs treatment can enhance production of TNF-α and IL-6. On the other hand, TNF-α and IL-6 show synergistic effects by altering osteocytes signaling towards osteoclasts and osteoblasts. In addition, TNF-α can induce osteocyte apoptosis and attribute to a worsened bone quality in GCs. IL-6 and osteocytes may interact with each other. Therefore, we hypothesize that GCs regulate osteocyteogenesis through TNF-α and IL-6, which are highly expressed around osteocyte undergoing apoptosis. In the present review, we summarized the roles of osteocytes in regulating osteoblasts and osteoclasts. Furthermore, the mechanism of GCs altered relationship between osteocytes and osteoblasts/osteoclasts. In addition, we discussed the roles of TNF-α and IL-6 in GIOP by modulating osteocytes. Lastly, we discussed the possibility of using pro-inflammatory signaling pathway as therapeutic targets to develop drugs for GIOP.
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Affiliation(s)
- Tiantian Wang
- Department of Rehabilitation Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan, 610041, China.,Key Laboratory of Rehabilitation Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan, 610041, China.,Laboratory of Endocrinology and Metabolism, Department of Endocrinology, National Key Laboratory of Biotherapy/Collaborative Innovation Center of Biotherapy and Cancer Center, West China Hospital, Sichuan University, 610041, China
| | - Xijie Yu
- Laboratory of Endocrinology and Metabolism, Department of Endocrinology, National Key Laboratory of Biotherapy/Collaborative Innovation Center of Biotherapy and Cancer Center, West China Hospital, Sichuan University, 610041, China
| | - Chengqi He
- Department of Rehabilitation Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan, 610041, China.,Key Laboratory of Rehabilitation Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan, 610041, China
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53
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FGF23 at the crossroads of phosphate, iron economy and erythropoiesis. Nat Rev Nephrol 2019; 16:7-19. [PMID: 31519999 DOI: 10.1038/s41581-019-0189-5] [Citation(s) in RCA: 149] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/24/2019] [Indexed: 12/20/2022]
Abstract
Fibroblast growth factor 23 (FGF23) was initially characterized as an important regulator of phosphate and calcium homeostasis. New research advances demonstrate that FGF23 is also linked to iron economy, inflammation and erythropoiesis. These advances have been fuelled, in part, by the serendipitous development of two distinct FGF23 assays that can substitute for invasive bone biopsies to infer the activity of the three main steps of FGF23 regulation in bone: transcription, post-translational modification and peptide cleavage. This 'liquid bone biopsy for FGF23 dynamics' enables large-scale longitudinal studies of FGF23 regulation that would otherwise be impossible in humans. The balance between FGF23 production, post-translational modification and cleavage is maintained or perturbed in different hereditary monogenic conditions and in acquired conditions that mimic these genetic disorders, including iron deficiency, inflammation, treatment with ferric carboxymaltose and chronic kidney disease. Looking ahead, a deeper understanding of the relationships between FGF23 regulation, iron homeostasis and erythropoiesis can be leveraged to devise novel therapeutic targets for treatment of anaemia and states of FGF23 excess, including chronic kidney disease.
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54
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He Q, Shumate LT, Matthias J, Aydin C, Wein MN, Spatz JM, Goetz R, Mohammadi M, Plagge A, Divieti Pajevic P, Bastepe M. A G protein-coupled, IP3/protein kinase C pathway controlling the synthesis of phosphaturic hormone FGF23. JCI Insight 2019; 4:125007. [PMID: 31484825 PMCID: PMC6777913 DOI: 10.1172/jci.insight.125007] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 08/01/2019] [Indexed: 12/23/2022] Open
Abstract
Dysregulated actions of bone-derived phosphaturic hormone fibroblast growth factor 23 (FGF23) result in several inherited diseases, such as X-linked hypophosphatemia (XLH), and contribute substantially to the mortality in kidney failure. Mechanisms governing FGF23 production are poorly defined. We herein found that ablation of the Gq/11α-like, extralarge Gα subunit (XLαs), a product of GNAS, exhibits FGF23 deficiency and hyperphosphatemia in early postnatal mice (XLKO). FGF23 elevation in response to parathyroid hormone, a stimulator of FGF23 production via cAMP, was intact in XLKO mice, while skeletal levels of protein kinase C isoforms α and δ (PKCα and PKCδ) were diminished. XLαs ablation in osteocyte-like Ocy454 cells suppressed the levels of FGF23 mRNA, inositol 1,4,5-trisphosphate (IP3), and PKCα/PKCδ proteins. PKC activation in vivo via injecting phorbol myristate acetate (PMA) or by constitutively active Gqα-Q209L in osteocytes and osteoblasts promoted FGF23 production. Molecular studies showed that the PKC activation-induced FGF23 elevation was dependent on MAPK signaling. The baseline PKC activity was elevated in bones of Hyp mice, a model of XLH. XLαs ablation significantly, but modestly, reduced serum FGF23 and elevated serum phosphate in Hyp mice. These findings reveal a potentially hitherto-unknown mechanism of FGF23 synthesis involving a G protein-coupled IP3/PKC pathway, which may be targeted to fine-tune FGF23 levels.
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Affiliation(s)
- Qing He
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Lauren T. Shumate
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Julia Matthias
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Cumhur Aydin
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
- Department of Endodontics, Gulhane Faculty of Dentistry, University of Health Sciences, Ankara, Turkey
| | - Marc N. Wein
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Jordan M. Spatz
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Regina Goetz
- Department of Biochemistry & Molecular Pharmacology, New York University School of Medicine, New York, New York, USA
| | - Moosa Mohammadi
- Department of Biochemistry & Molecular Pharmacology, New York University School of Medicine, New York, New York, USA
| | - Antonius Plagge
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool, United Kingdom
| | - Paola Divieti Pajevic
- Department of Molecular & Cell Biology, Boston University Goldman School of Dental Medicine, Boston, Massachusetts, USA
| | - Murat Bastepe
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
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55
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Abstract
Fibroblast growth factor 23 (FGF23), one of the endocrine fibroblast growth factors, is a principal regulator in the maintenance of serum phosphorus concentration. Binding to its cofactor αKlotho and a fibroblast growth factor receptor is essential for its activity. Its regulation and interaction with other factors in the bone-parathyroid-kidney axis is complex. FGF23 reduces serum phosphorus concentration through decreased reabsorption of phosphorus in the kidney and by decreasing 1,25 dihydroxyvitamin D (1,25(OH)2D) concentrations. Various FGF23-mediated disorders of renal phosphate wasting share similar clinical and biochemical features. The most common of these is X-linked hypophosphatemia (XLH). Additional disorders of FGF23 excess include autosomal dominant hypophosphatemic rickets, autosomal recessive hypophosphatemic rickets, fibrous dysplasia, and tumor-induced osteomalacia. Treatment is challenging, requiring careful monitoring and titration of dosages to optimize effectiveness and to balance side effects. Conventional therapy for XLH and other disorders of FGF23-mediated hypophosphatemia involves multiple daily doses of oral phosphate salts and active vitamin D analogs, such as calcitriol or alfacalcidol. Additional treatments may be used to help address side effects of conventional therapy such as thiazides to address hypercalciuria or nephrocalcinosis, and calcimimetics to manage hyperparathyroidism. The recent development and approval of an anti-FGF23 antibody, burosumab, for use in XLH provides a novel treatment option.
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Affiliation(s)
- Anisha Gohil
- Indiana University School of Medicine, Riley Hospital for Children, Fellow, Endocrinology and Diabetes, 705 Riley Hospital Drive, Room 5960, Indianapolis, IN 46202, USA, E-mail:
| | - Erik A Imel
- Indiana University School of Medicine, Riley Hospital for Children, Associate Professor of Medicine and Pediatrics, 1120 West Michigan Street, CL 459, Indianapolis, IN 46202, USA
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56
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Bär L, Stournaras C, Lang F, Föller M. Regulation of fibroblast growth factor 23 (FGF23) in health and disease. FEBS Lett 2019; 593:1879-1900. [PMID: 31199502 DOI: 10.1002/1873-3468.13494] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 03/26/2019] [Accepted: 03/27/2019] [Indexed: 12/19/2022]
Abstract
Fibroblast growth factor 23 (FGF23) is mainly produced in the bone and, upon secretion, forms a complex with a FGF receptor and coreceptor αKlotho. FGF23 can exert several endocrine functions, such as inhibiting renal phosphate reabsorption and 1,25-dihydroxyvitamin D3 production. Moreover, it has paracrine activities on several cell types, including neutrophils and hepatocytes. Klotho and Fgf23 deficiencies result in pathologies otherwise encountered in age-associated diseases, mainly as a result of hyperphosphataemia-dependent calcification. FGF23 levels are also perturbed in the plasma of patients with several disorders, including kidney or cardiovascular diseases. Here, we review mechanisms controlling FGF23 production and discuss how FGF23 regulation is perturbed in disease.
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Affiliation(s)
- Ludmilla Bär
- Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Christos Stournaras
- Institute of Biochemistry, University of Crete Medical School, Heraklion, Greece
| | - Florian Lang
- Institute of Physiology, University of Tübingen, Germany
| | - Michael Föller
- Institute of Physiology, University of Hohenheim, Stuttgart, Germany
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57
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Chandran M, Wong J. Secondary and Tertiary Hyperparathyroidism in Chronic Kidney Disease: An Endocrine and Renal Perspective. Indian J Endocrinol Metab 2019; 23:391-399. [PMID: 31741895 PMCID: PMC6844175 DOI: 10.4103/ijem.ijem_292_19] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Secondary Hyperparathyroidism (SHP) seen as a frequent complication in Chronic Kidney Disease (CKD) has many pathogenetic peculiarities that are still incompletely defined and understood. During the long course of chronic renal failure, SHP can also transform sometimes into the hypercalcemic state characterized by quasi-autonomous production of Parathyroid Hormone from the parathyroid glands: a disorder that is termed Tertiary Hyperparathyroidism. The clinical consequences of SHP in CKD are protean, encompassing bone and mineral abnormalities but as recently identified, also several metabolic and cardiovascular problems, the most important of which is vascular calcification. There have been several advances in the therapeutic armamentarium available for the treatment of SHP, though clear demonstration of a benefit regarding major clinical outcomes with any of the new agents is still lacking. This narrative review summarizes the current understanding about this disorder and highlights some of the recent research on the subject.
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Affiliation(s)
- Manju Chandran
- Department of Endocrinology, Osteoporosis and Bone Metabolism Unit, Singapore General Hospital, Singapore
| | - Jiunn Wong
- Department of Renal Medicine, Singapore General Hospital, Singapore
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58
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Wada E, Hamano T, Matsui I, Yoshida M, Hayashi YK, Matsuda R. Renal involvement in the pathogenesis of mineral and bone disorder in dystrophin-deficient mdx mouse. J Physiol Sci 2019; 69:661-671. [PMID: 31079351 PMCID: PMC10717053 DOI: 10.1007/s12576-019-00683-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 04/30/2019] [Indexed: 12/18/2022]
Abstract
Duchenne muscular dystrophy is a severe muscular disorder, often complicated with osteoporosis, and impaired renal function has recently been featured. We aimed to clarify the involvement of renal function in the pathogenesis of mineral and bone disorder in mdx mice, a murine model of the disease. We clearly revealed renal dysfunction in adult mdx mice, in which dehydration and hypercalcemia were contributed. We also examined the effects of dietary phosphorus (P) overload on phosphate metabolism. Serum phosphate and parathyroid hormone (PTH) levels were significantly increased in mdx mice by dietary P in a dose-dependent manner; however, bone alkaline phosphatase levels were significantly lower in mdx mice. Additionally, bone mineral density in mdx mice were even worsened by increased dietary P in a dose-dependent manner. These results suggested that the uncoupling of bone formation and resorption was enhanced by skeletal resistance to PTH due to renal failure in mdx mice.
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Affiliation(s)
- Eiji Wada
- Department of Pathophysiology, Tokyo Medical University, 6-1-1 Shinjuku, Shinjuku, Tokyo, 160-8402, Japan.
- Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo, 153-8902, Japan.
| | - Takayuki Hamano
- Department of Comprehensive Kidney Disease Research, Osaka University Graduate of School Medicine, B6-2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Isao Matsui
- Department of Comprehensive Kidney Disease Research, Osaka University Graduate of School Medicine, B6-2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Mizuko Yoshida
- Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo, 153-8902, Japan
| | - Yukiko K Hayashi
- Department of Pathophysiology, Tokyo Medical University, 6-1-1 Shinjuku, Shinjuku, Tokyo, 160-8402, Japan
| | - Ryoichi Matsuda
- Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo, 153-8902, Japan
- Graduate School of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku, Tokyo, 162-8601, Japan
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Billington EO, Murphy R, Gamble GD, Callon K, Davies N, Plank LD, Booth M, Reid IR. Fibroblast growth factor 23 levels decline following sleeve gastrectomy. Clin Endocrinol (Oxf) 2019; 91:87-93. [PMID: 30943313 DOI: 10.1111/cen.13981] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 03/29/2019] [Accepted: 03/31/2019] [Indexed: 12/25/2022]
Abstract
OBJECTIVE Levels of fibroblast growth factor 23 (FGF23) have been positively associated with measures of adiposity, cardiovascular disease and mortality. It is unclear whether the relationship of FGF23 with cardiovascular disease and mortality is confounded by obesity. We aimed to determine whether FGF23 concentrations decline following a reduction in adiposity after sleeve gastrectomy (SG). DESIGN The effect of SG on FGF23 was evaluated in 22 obese adults (59% male) with type 2 diabetes. Fat mass, weight, BMI, plasma intact FGF23, parathyroid hormone (PTH) and leptin were determined at baseline and at 12 months following SG. RESULTS At baseline, median (IQR) age was 51 (43-54) years, fat mass 47.8 (41.0-59.4) kg, BMI 40.9 (36.9-46.9) kg/m2 and FGF23 66.2 (55.3-82.9) pg/mL. Significant changes in median BMI (-10.8 kg/m2 , 95% CI: -12.9 to -7.2, P < 0.0001), fat mass (-20.0 kg, 95% CI: -26.7 to -12.4, P < 0.0001) and weight (-34.7 kg, 95% CI -40.0 to -23.1, P < 0.0001) were observed after SG. FGF23 (-12.4 pg/mL, 95% CI: -19.5 to 2.0, P = 0.005), PTH (-1.1 pmol/L, 95% CI: -1.7 to 0.2, P = 0.009) and leptin (-1687 pg/mL, 95% CI -4524 to -563, P = 0.01) declined following SG. Change in FGF23 was not significantly associated with change in measures of adiposity, PTH or leptin. CONCLUSIONS FGF23 concentrations decline in the setting of significant weight loss following SG, implying that increased FGF23 concentrations are a downstream consequence of obesity, which may confound its association with cardiometabolic dysfunction. Mediators of the relationship between adiposity and FGF23 require further elucidation.
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Affiliation(s)
- Emma O Billington
- Faculty of Medical and Health Sciences, Department of Medicine, University of Auckland, Auckland, New Zealand
- Cumming School of Medicine, Division of Endocrinology & Metabolism, University of Calgary, Calgary, Alberta, Canada
| | - Rinki Murphy
- Faculty of Medical and Health Sciences, Department of Medicine, University of Auckland, Auckland, New Zealand
| | - Greg D Gamble
- Faculty of Medical and Health Sciences, Department of Medicine, University of Auckland, Auckland, New Zealand
| | - Karen Callon
- Faculty of Medical and Health Sciences, Department of Medicine, University of Auckland, Auckland, New Zealand
| | - Naomi Davies
- Faculty of Medical and Health Sciences, Department of Medicine, University of Auckland, Auckland, New Zealand
| | - Lindsay D Plank
- Faculty of Medical and Health Sciences, Department of Surgery, University of Auckland, Auckland, New Zealand
| | - Michael Booth
- Department of Surgery, North Shore Hospital, Waitemata District Health Board, Auckland, New Zealand
| | - Ian R Reid
- Faculty of Medical and Health Sciences, Department of Medicine, University of Auckland, Auckland, New Zealand
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60
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Egli-Spichtig D, Imenez Silva PH, Glaudemans B, Gehring N, Bettoni C, Zhang MYH, Pastor-Arroyo EM, Schönenberger D, Rajski M, Hoogewijs D, Knauf F, Misselwitz B, Frey-Wagner I, Rogler G, Ackermann D, Ponte B, Pruijm M, Leichtle A, Fiedler GM, Bochud M, Ballotta V, Hofmann S, Perwad F, Föller M, Lang F, Wenger RH, Frew I, Wagner CA. Tumor necrosis factor stimulates fibroblast growth factor 23 levels in chronic kidney disease and non-renal inflammation. Kidney Int 2019; 96:890-905. [PMID: 31301888 DOI: 10.1016/j.kint.2019.04.009] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 03/11/2019] [Accepted: 04/05/2019] [Indexed: 01/03/2023]
Abstract
Fibroblast growth factor 23 (FGF23) regulates phosphate homeostasis, and its early rise in patients with chronic kidney disease is independently associated with all-cause mortality. Since inflammation is characteristic of chronic kidney disease and associates with increased plasma FGF23 we examined whether inflammation directly stimulates FGF23. In a population-based cohort, plasma tumor necrosis factor (TNF) was the only inflammatory cytokine that independently and positively correlated with plasma FGF23. Mouse models of chronic kidney disease showed signs of renal inflammation, renal FGF23 expression and elevated systemic FGF23 levels. Renal FGF23 expression coincided with expression of the orphan nuclear receptor Nurr1 regulating FGF23 in other organs. Antibody-mediated neutralization of TNF normalized plasma FGF23 and suppressed ectopic renal Fgf23 expression. Conversely, TNF administration to control mice increased plasma FGF23 without altering plasma phosphate. Moreover, in Il10-deficient mice with inflammatory bowel disease and normal kidney function, plasma FGF23 was elevated and normalized upon TNF neutralization. Thus, the inflammatory cytokine TNF contributes to elevated systemic FGF23 levels and also triggers ectopic renal Fgf23 expression in animal models of chronic kidney disease.
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Affiliation(s)
- Daniela Egli-Spichtig
- Institute of Physiology, University of Zurich, Zurich, Switzerland; Swiss National Center of Competence in Research NCCR-Kidney.CH, University of Zurich, Zurich, Switzerland; Department of Pediatrics, Division of Nephrology, University of California, San Francisco, San Francisco, California, USA
| | - Pedro Henrique Imenez Silva
- Institute of Physiology, University of Zurich, Zurich, Switzerland; Swiss National Center of Competence in Research NCCR-Kidney.CH, University of Zurich, Zurich, Switzerland
| | - Bob Glaudemans
- Institute of Physiology, University of Zurich, Zurich, Switzerland; Swiss National Center of Competence in Research NCCR-Kidney.CH, University of Zurich, Zurich, Switzerland
| | - Nicole Gehring
- Institute of Physiology, University of Zurich, Zurich, Switzerland; Swiss National Center of Competence in Research NCCR-Kidney.CH, University of Zurich, Zurich, Switzerland
| | - Carla Bettoni
- Institute of Physiology, University of Zurich, Zurich, Switzerland; Swiss National Center of Competence in Research NCCR-Kidney.CH, University of Zurich, Zurich, Switzerland
| | - Martin Y H Zhang
- Department of Pediatrics, Division of Nephrology, University of California, San Francisco, San Francisco, California, USA
| | - Eva M Pastor-Arroyo
- Institute of Physiology, University of Zurich, Zurich, Switzerland; Swiss National Center of Competence in Research NCCR-Kidney.CH, University of Zurich, Zurich, Switzerland
| | - Désirée Schönenberger
- Institute of Physiology, University of Zurich, Zurich, Switzerland; Swiss National Center of Competence in Research NCCR-Kidney.CH, University of Zurich, Zurich, Switzerland
| | - Michal Rajski
- Institute of Physiology, University of Zurich, Zurich, Switzerland; Swiss National Center of Competence in Research NCCR-Kidney.CH, University of Zurich, Zurich, Switzerland
| | - David Hoogewijs
- Institute of Physiology, University of Zurich, Zurich, Switzerland; Swiss National Center of Competence in Research NCCR-Kidney.CH, University of Zurich, Zurich, Switzerland
| | - Felix Knauf
- Division of Nephrology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Benjamin Misselwitz
- University Hospital Zurich, Clinic for Gastroenterology and Hepatology, Zurich, Switzerland
| | - Isabelle Frey-Wagner
- University Hospital Zurich, Clinic for Gastroenterology and Hepatology, Zurich, Switzerland
| | - Gerhard Rogler
- University Hospital Zurich, Clinic for Gastroenterology and Hepatology, Zurich, Switzerland
| | - Daniel Ackermann
- Department of Nephrology and Hypertension, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Belen Ponte
- Department of Nephrology, University Hospital of Geneva (HUG), Geneva, Switzerland
| | - Menno Pruijm
- Department of Nephrology, Lausanne University Hospital (CHUV), Lausanne, Switzerland
| | - Alexander Leichtle
- Institute of Clinical Chemistry, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Georg-Martin Fiedler
- Institute of Clinical Chemistry, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Murielle Bochud
- Swiss National Center of Competence in Research NCCR-Kidney.CH, University of Zurich, Zurich, Switzerland; Institute of Social and Preventive Medicine (IUMSP), Lausanne University Hospital (CHUV), Lausanne, Switzerland
| | - Virginia Ballotta
- Department of Biomedical Engineering and Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Sandra Hofmann
- Department of Biomedical Engineering and Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Farzana Perwad
- Department of Pediatrics, Division of Nephrology, University of California, San Francisco, San Francisco, California, USA
| | - Michael Föller
- Institute of Physiology, University of Hohenheim, Stuttgart, Germany
| | - Florian Lang
- Institute of Physiology I, University of Tübingen, Tübingen, Germany
| | - Roland H Wenger
- Institute of Physiology, University of Zurich, Zurich, Switzerland; Swiss National Center of Competence in Research NCCR-Kidney.CH, University of Zurich, Zurich, Switzerland
| | - Ian Frew
- Institute of Physiology, University of Zurich, Zurich, Switzerland; Swiss National Center of Competence in Research NCCR-Kidney.CH, University of Zurich, Zurich, Switzerland
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland; Swiss National Center of Competence in Research NCCR-Kidney.CH, University of Zurich, Zurich, Switzerland.
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Nagata Y, Imanishi Y, Ohara M, Maeda-Tateishi T, Miyaoka D, Hayashi N, Kurajoh M, Emoto M, Inaba M. Attenuated Dentin Matrix Protein 1 Enhances Fibroblast Growth Factor 23 in Calvaria in a Primary Hyperparathyroidism Model. Endocrinology 2019; 160:1348-1358. [PMID: 30916761 DOI: 10.1210/en.2019-00017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 03/21/2019] [Indexed: 12/20/2022]
Abstract
Fibroblast growth factor 23 (FGF23) secretion is facilitated by the PTH, particularly in hyperparathyroidism. The PTH also attenuates dentin matrix protein 1 (DMP1), which is produced by osteocytes to contribute to bone mineralization and suppress FGF23 expression. Nevertheless, it remains unknown whether attenuated DMP1 affects FGF23 expression in hyperparathyroidism. We examined their expression in bone tissue using a mouse model of primary hyperparathyroidism (PHPT). PHPT mice increased serum FGF23 levels, along with a high level of serum PTH. Fgf23 expression increased, and Dmp1 decreased significantly in the calvaria of PHPT mice compared with wild-type mice and primary osteoblasts treated with PTH. In UMR106 mature osteoblasts, PTH increased Fgf23 expression and decreased Dmp1 expression, and stimulation of protein kinase A (PKA) signaling by forskolin also increased Fgf23 expression and decreased Dmp1 expression in a dose-dependent manner, whereas inhibition of PKA signaling with 10-5 M H89 reversed the changes in Fgf23 and Dmp1 expression when cells were stimulated with PTH. Silencing Dmp1 along with PTH treatment led to an additive increase in Fgf23 expression, accompanied by additive phosphorylation of the cAMP-response element-binding protein. These results indicate that persistent and high levels of PTH lead to the continuous activation of PKA signaling in osteoblasts/osteocytes, resulting in an increase in FGF23 and a decrease in DMP1 in bone. Moreover, suppression of DMP1 enhanced FGF23 expression in PHPT, besides having a direct effect on PTH. These mechanisms may describe one of the pathogeneses behind the increase in FGF23 transcription in bone tissue in patients with PHPT.
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Affiliation(s)
- Yuki Nagata
- Department of Metabolism, Endocrinology, and Molecular Medicine, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Yasuo Imanishi
- Department of Metabolism, Endocrinology, and Molecular Medicine, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Masaya Ohara
- Department of Metabolism, Endocrinology, and Molecular Medicine, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Tomomi Maeda-Tateishi
- Department of Metabolism, Endocrinology, and Molecular Medicine, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Daichi Miyaoka
- Department of Metabolism, Endocrinology, and Molecular Medicine, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Noriyuki Hayashi
- Department of Metabolism, Endocrinology, and Molecular Medicine, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Masafumi Kurajoh
- Department of Metabolism, Endocrinology, and Molecular Medicine, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Masanori Emoto
- Department of Metabolism, Endocrinology, and Molecular Medicine, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Masaaki Inaba
- Department of Metabolism, Endocrinology, and Molecular Medicine, Osaka City University Graduate School of Medicine, Osaka, Japan
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Wolf M, Block GA, Chertow GM, Cooper K, Fouqueray B, Moe SM, Sun Y, Tomlin H, Vervloet M, Oberbauer R. Effects of etelcalcetide on fibroblast growth factor 23 in patients with secondary hyperparathyroidism receiving hemodialysis. Clin Kidney J 2019; 13:75-84. [PMID: 32082556 PMCID: PMC7025329 DOI: 10.1093/ckj/sfz034] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 03/11/2019] [Indexed: 12/11/2022] Open
Abstract
Background Etelcalcetide is an intravenous calcimimetic approved for treatment of secondary hyperparathyroidism (sHPT) in patients receiving hemodialysis. Besides lowering parathyroid hormone (PTH), etelcalcetide also significantly reduces fibroblast growth factor 23 (FGF23), but the mechanisms are unknown. Methods To investigate potential mediators of etelcalcetide-induced FGF23 reduction, we performed secondary analyses of the 26-week randomized trials that compared the effects on PTH of etelcalcetide (n = 509) versus placebo (n = 514) and etelcalcetide (n = 340) versus cinacalcet (n = 343) in adults with sHPT receiving hemodialysis. We analyzed changes in FGF23 in relation to changes in PTH, calcium, phosphate and bone turnover markers. We also investigated how concomitant treatments aimed at mitigating hypocalcemia altered the FGF23-lowering effects of etelcalcetide. Results Etelcalcetide reduced FGF23 [median % change (quartile 1–quartile 3)] from baseline to the end of the trial significantly more than placebo [–56% (–85 to –7) versus +2% (–40 to +65); P < 0.001] and cinacalcet [–68% (–87 to –26) versus –41% (–76 to +25); P < 0.001]. Reductions in FGF23 correlated strongly with reductions in calcium and phosphate, but not with PTH; correlations with bone turnover markers were inconsistent and of borderline significance. Increases in concomitant vitamin D administration partially attenuated the FGF23-lowering effect of etelcalcetide, but increased dialysate calcium concentration versus no increase and increased dose of calcium supplementation versus no increase did not attenuate the FGF23-lowering effects of etelcalcetide. Conclusion These data suggest that etelcalcetide potently lowers FGF23 in patients with sHPT receiving hemodialysis and that the effect remains detectable among patients who receive concomitant treatments aimed at mitigating treatment-associated decreases in serum calcium.
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Affiliation(s)
- Myles Wolf
- Department of Medicine, Division of Nephrology, Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC, USA
| | | | - Glenn M Chertow
- Department of Medicine, Division of Nephrology, Stanford University School of Medicine, Palo Alto, CA, USA
| | | | | | - Sharon M Moe
- Department of Medicine, Division of Nephrology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Yan Sun
- Amgen, Inc., Thousand Oaks, CA, USA
| | | | - Marc Vervloet
- Department of Nephrology, VU University Medical Center, Amsterdam, The Netherlands
| | - Rainer Oberbauer
- Department of Nephrology, Medical University of Vienna, Vienna, Austria
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Toxines urémiques de moyen poids moléculaire : un véritable regain d’intérêt. Nephrol Ther 2019; 15:82-90. [DOI: 10.1016/j.nephro.2018.09.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 09/02/2018] [Indexed: 01/20/2023]
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Rodelo-Haad C, Santamaria R, Muñoz-Castañeda JR, Pendón-Ruiz de Mier MV, Martin-Malo A, Rodriguez M. FGF23, Biomarker or Target? Toxins (Basel) 2019; 11:E175. [PMID: 30909513 PMCID: PMC6468608 DOI: 10.3390/toxins11030175] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 03/14/2019] [Accepted: 03/19/2019] [Indexed: 12/11/2022] Open
Abstract
Fibroblast growth factor 23 (FGF23) plays a key role in the complex network between the bones and other organs. Initially, it was thought that FGF23 exclusively regulated phosphate and vitamin D metabolism; however, recent research has demonstrated that an excess of FGF23 has other effects that may be detrimental in some cases. The understanding of the signaling pathways through which FGF23 acts in different organs is crucial to develop strategies aiming to prevent the negative effects associated with high FGF23 levels. FGF23 has been described to have effects on the heart, promoting left ventricular hypertrophy (LVH); the liver, leading to production of inflammatory cytokines; the bones, inhibiting mineralization; and the bone marrow, by reducing the production of erythropoietin (EPO). The identification of FGF23 receptors will play a remarkable role in future research since its selective blockade might reduce the adverse effects of FGF23. Patients with chronic kidney disease (CKD) have very high levels of FGF23 and may be the population suffering from the most adverse FGF23-related effects. The general population, as well as kidney transplant recipients, may also be affected by high FGF23. Whether the association between FGF23 and clinical events is causal or casual remains controversial. The hypothesis that FGF23 could be considered a therapeutic target is gaining relevance and may become a promising field of investigation in the future.
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Affiliation(s)
- Cristian Rodelo-Haad
- Nephrology Service, University Hospital Reina Sofia, 14005 Cordoba, Spain.
- Maimonides Institute for Biomedical Research of Cordoba (IMIBIC)/University of Cordoba, 14005 Cordoba, Spain.
- Spanish Renal Research Network (REDinREN), Institute of Health Carlos III, 28040 Madrid, Spain.
| | - Rafael Santamaria
- Nephrology Service, University Hospital Reina Sofia, 14005 Cordoba, Spain.
- Maimonides Institute for Biomedical Research of Cordoba (IMIBIC)/University of Cordoba, 14005 Cordoba, Spain.
- Spanish Renal Research Network (REDinREN), Institute of Health Carlos III, 28040 Madrid, Spain.
| | - Juan R Muñoz-Castañeda
- Nephrology Service, University Hospital Reina Sofia, 14005 Cordoba, Spain.
- Maimonides Institute for Biomedical Research of Cordoba (IMIBIC)/University of Cordoba, 14005 Cordoba, Spain.
- Spanish Renal Research Network (REDinREN), Institute of Health Carlos III, 28040 Madrid, Spain.
| | - M Victoria Pendón-Ruiz de Mier
- Nephrology Service, University Hospital Reina Sofia, 14005 Cordoba, Spain.
- Maimonides Institute for Biomedical Research of Cordoba (IMIBIC)/University of Cordoba, 14005 Cordoba, Spain.
- Spanish Renal Research Network (REDinREN), Institute of Health Carlos III, 28040 Madrid, Spain.
| | - Alejandro Martin-Malo
- Nephrology Service, University Hospital Reina Sofia, 14005 Cordoba, Spain.
- Maimonides Institute for Biomedical Research of Cordoba (IMIBIC)/University of Cordoba, 14005 Cordoba, Spain.
- Spanish Renal Research Network (REDinREN), Institute of Health Carlos III, 28040 Madrid, Spain.
| | - Mariano Rodriguez
- Nephrology Service, University Hospital Reina Sofia, 14005 Cordoba, Spain.
- Maimonides Institute for Biomedical Research of Cordoba (IMIBIC)/University of Cordoba, 14005 Cordoba, Spain.
- Spanish Renal Research Network (REDinREN), Institute of Health Carlos III, 28040 Madrid, Spain.
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Abstract
PURPOSE OF REVIEW The phosphaturic hormone FGF23 is produced primarily in osteoblasts/osteocytes and is known to respond to increases in serum phosphate and 1,25(OH)2 vitamin D (1,25D). Novel regulators of FGF23 were recently identified, and may help explain the pathophysiologies of several diseases. This review will focus on recent studies examining the synthesis and actions of FGF23. RECENT FINDINGS The synthesis of FGF23 in response to 1,25D is similar to other steroid hormone targets, but the cellular responses to phosphate remain largely unknown. The activity of intracellular processing genes control FGF23 glycosylation and phosphorylation, providing critical functions in determining the serum levels of bioactive FGF23. The actions of FGF23 largely occur through its co-receptor αKlotho (KL) under normal circumstances, but FGF23 has KL-independent activity during situations of high concentrations. SUMMARY Recent work regarding FGF23 synthesis and bioactivity, as well as considerations for diseases of altered phosphate balance will be reviewed.
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Affiliation(s)
- Megan L Noonan
- Department of Medical & Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Kenneth E White
- Department of Medical & Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
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Abstract
Calcium kidney stones are common worldwide. Most are idiopathic and composed of calcium oxalate. Calcium phosphate is present in around 80% and may initiate stone formation. Stone production is multifactorial with a polygenic genetic contribution. Phosphaturia is found frequently among stone formers but until recently received scant attention. This review examines possible mechanisms for the phosphaturia and its relevance to stone formation from a wide angle. There is a striking lack of clinical data. Phosphaturia is associated, but not correlated, with hypercalciuria, increased 1,25 dihydroxy-vitamin D [1,25 (OH)2D], and sometimes evidence of disturbances in proximal renal tubular function. Phosphate reabsorption in the proximal renal tubules requires tightly regulated interaction of many proteins. Paracellular flow through intercellular tight junctions is the major route of phosphate absorption from the intestine and can be reduced therapeutically in hyperphosphatemic patients. In monogenic defects stones develop when phosphaturia is associated with hypercalciuria, generally explained by increased 1,25 (OH)2D production in response to hypophosphatemia. Calcification does not occur in disorders with increased FGF23 when phosphaturia occurs in isolation and 1,25 (OH)2D is suppressed. Candidate gene studies have identified mutations in the phosphate transporters, but in few individuals. One genome-wide study identified a polymorphism of the phosphate transporter gene SLC34A4 associated with stones. Others did not find mutations obviously linked to phosphate reabsorption. Future genetic studies should have a wide trawl and should focus initially on groups of patients with clearly defined phenotypes. The global data should be pooled.
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Affiliation(s)
- Valerie Walker
- Department of Clinical Biochemistry, University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom.
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Choi H, Magyar CE, Nervina JM, Tetradis S. Different duration of parathyroid hormone exposure distinctively regulates primary response genes Nurr1 and RANKL in osteoblasts. PLoS One 2018; 13:e0208514. [PMID: 30576321 PMCID: PMC6303058 DOI: 10.1371/journal.pone.0208514] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 11/19/2018] [Indexed: 12/19/2022] Open
Abstract
Parathyroid hormone (PTH) exerts dual effects, anabolic or catabolic, on bone when administrated intermittently or continuously, via mechanisms that remain largely unknown. PTH binding to cells induces PTH-responsive genes including primary response genes (PRGs). PRGs are rapidly induced without the need for de novo protein synthesis, thereby playing pivotal roles in directing subsequent molecular responses. In this study, to understand the role of PRGs in mediating osteoblastic cellular responses to PTH, we investigated whether various durations of PTH differentially induce PRGs in primary osteoblasts and MC3T3-E1. Nurr1 and RANKL, PRGs known for their anabolic and catabolic roles in bone metabolism respectively, presented distinctive transient vs. sustained induction kinetics. Corroborating their roles, maximum induction of Nurr1 was sufficiently achieved by brief PTH in as little as 30 minutes and continued beyond that, while maximum induction of RANKL was achieved only by prolonged PTH over 4 hours. Our data suggested distinctive regulatory mechanisms for Nurr1 and RANKL: PKA-mediated chromatin rearrangement for transcriptional regulation of both PRGs and ERK-mediated transcriptional regulation for RANKL but not Nurr1. Lastly, we classified PRGs into two groups based on the induction kinetics: The group that required brief PTH for maximum induction included Nur77, cox-2, and Nurr1, all of which are reported to play roles in bone formation. The other group that required prolonged PTH for maximum induction included IL-6 and RANKL, which play roles in bone resorption. Together, our data suggested the crucial role of PRG groups in mediating differential osteoblastic cellular responses to intermittent vs. continuous PTH. Continued research into the regulatory mechanisms of PKA and ERK for PRGs will help us better understand the molecular mechanisms underlying the dual effects of PTH, thereby optimizing the current therapeutic use of PTH for osteoporosis.
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Affiliation(s)
- Hyewon Choi
- Division of Oral Biology and Medicine, School of Dentistry, University of California at Los Angeles, Los Angeles, California, United States of America
| | - Clara E. Magyar
- Center for Pathology Research Services, Department of Pathology, University of California at Los Angeles, Los Angeles, California, United States of America
| | - Jeanne M. Nervina
- College of Dentistry, New York University, New York, New York, United States of America
| | - Sotirios Tetradis
- Division of Oral Biology and Medicine, School of Dentistry, University of California at Los Angeles, Los Angeles, California, United States of America
- Division of Diagnostic and Surgical Sciences, School of Dentistry, University of California at Los Angeles, Los Angeles, California, United States of America
- * E-mail:
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Abstract
Inorganic phosphate (Pi) is essential for signal transduction and cell metabolism, and is also an essential structural component of the extracellular matrix of the skeleton. Pi is sensed in bacteria and yeast at the plasma membrane, which activates intracellular signal transduction to control the expression of Pi transporters and other genes that control intracellular Pi levels. In multicellular organisms, Pi homeostasis must be maintained in the organism and at the cellular level, requiring an endocrine and metabolic Pi-sensing mechanism, about which little is currently known. This Review will discuss the metabolic effects of Pi, which are mediated by Pi transporters, inositol pyrophosphates and SYG1-Pho81-XPR1 (SPX)-domain proteins to maintain cellular phosphate homeostasis in the musculoskeletal system. In addition, we will discuss how Pi is sensed by the human body to regulate the production of fibroblast growth factor 23 (FGF23), parathyroid hormone and calcitriol to maintain serum levels of Pi in a narrow range. New findings on the crosstalk between iron and Pi homeostasis in the regulation of FGF23 expression will also be outlined. Mutations in components of these metabolic and endocrine phosphate sensors result in genetic disorders of phosphate homeostasis, cardiomyopathy and familial basal ganglial calcifications, highlighting the importance of this newly emerging area of research.
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Affiliation(s)
- Sampada Chande
- Section of Endocrinology and Metabolism, Yale University School of Medicine, New Haven, CT, USA
| | - Clemens Bergwitz
- Section of Endocrinology and Metabolism, Yale University School of Medicine, New Haven, CT, USA.
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Iwasaki Y, Yamato H, Fukagawa M. TGF-Beta Signaling in Bone with Chronic Kidney Disease. Int J Mol Sci 2018; 19:E2352. [PMID: 30103389 PMCID: PMC6121599 DOI: 10.3390/ijms19082352] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 07/30/2018] [Accepted: 08/08/2018] [Indexed: 01/05/2023] Open
Abstract
Transforming growth factor (TGF)-β signaling is not only important in skeletal development, but also essential in bone remodeling in adult bone. The bone remodeling process involves integrated cell activities induced by multiple stimuli to balance bone resorption and bone formation. TGF-β plays a role in bone remodeling by coordinating cell activities to maintain bone homeostasis. However, mineral metabolism disturbance in chronic kidney disease (CKD) results in abnormal bone remodeling, which leads to ectopic calcification in CKD. High circulating levels of humoral factors such as parathyroid hormone, fibroblast growth factor 23, and Wnt inhibitors modulate bone remodeling in CKD. Several reports have revealed that TGF-β is involved in the production and functions of these factors in bone. TGF-β may act as a factor that mediates abnormal bone remodeling in CKD.
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Affiliation(s)
- Yoshiko Iwasaki
- Department of Health Sciences, Oita University of Nursing and Health Sciences, Oita 870-1163, Japan.
| | - Hideyuki Yamato
- Division of Nephrology and Metabolism, Tokai University School of Medicine, Kanagawa 259-119, Japan.
| | - Masafumi Fukagawa
- Division of Nephrology and Metabolism, Tokai University School of Medicine, Kanagawa 259-119, Japan.
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Rodelo-Haad C, Rodríguez-Ortiz ME, Martin-Malo A, Pendon-Ruiz de Mier MV, Agüera ML, Muñoz-Castañeda JR, Soriano S, Caravaca F, Alvarez-Lara MA, Felsenfeld A, Aljama P, Rodriguez M. Phosphate control in reducing FGF23 levels in hemodialysis patients. PLoS One 2018; 13:e0201537. [PMID: 30086150 PMCID: PMC6080760 DOI: 10.1371/journal.pone.0201537] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 07/04/2018] [Indexed: 02/07/2023] Open
Abstract
Background In hemodialysis patients, high levels of Fibroblast Growth Factor 23 (FGF23) predict mortality. Our study was designed to test whether the control of serum phosphate is associated with a reduction in serum FGF23 levels. Additionally other variables with a potential effect on FGF23 levels were evaluated. Material and methods The effect of sustained (40-weeks) control of serum phosphate on FGF23 levels (intact and c-terminal) was evaluated in 21 stable hemodialysis patients that were not receiving calcimimetics or active vitamin D. Patients received non-calcium phosphate binders to maintain serum phosphate below 4.5 mg/dl. In an additional analysis, values of intact-FGF23 (iFGF23) and c-terminal FGF23 (cFGF23) from 150 hemodialysis patients were correlated with parameters of mineral metabolism and inflammation. Linear mixed models and linear regression were performed to evaluate longitudinal trajectories of variables and the association between FGF23 and the other variables examined. Results During the 40-week treatment, 12 of 21 patients achieved the target of serum phosphate <4.5 mg/dl. In these 12 patients, iFGF23 decreased to less than half whereas cFGF23 did not reduce significantly. In patients with serum phosphate >4.5 mg, iFGF23 and cFGF23 increased two and four-fold respectively as compared with baseline. Furthermore, changes in serum phosphate correlated with changes in C-reactive protein (hs-CRP). In our 150 hemodialysis patients, those in the higher tertile of serum phosphate also showed increased hs-CRP, iPTH, iFGF23 and cFGF23. Multiple regression analysis revealed that iFGF23 levels directly correlated with both serum phosphate and calcium, whereas cFGF23 correlated with serum phosphate and hs-CRP but not with calcium. Conclusions The control of serum phosphate reduced iFGF23. This reduction was also associated with a decreased in inflammatory parameters. Considering the entire cohort of hemodialysis patients, iFGF23 levels correlated directly with serum phosphate levels and also correlated inversely with serum calcium concentration. The levels of cFGF23 were closely related to serum phosphate and parameters of inflammation.
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Affiliation(s)
- Cristian Rodelo-Haad
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Reina Sofia University Hospital, University of Cordoba, Cordoba, Spain
- Nephrology Service, Reina Sofia University Hospital, Cordoba, Spain
- RETICs-REDinREN (National Institute of Health Carlos III), Madrid, Spain
| | - Maria E. Rodríguez-Ortiz
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Reina Sofia University Hospital, University of Cordoba, Cordoba, Spain
- RETICs-REDinREN (National Institute of Health Carlos III), Madrid, Spain
| | - Alejandro Martin-Malo
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Reina Sofia University Hospital, University of Cordoba, Cordoba, Spain
- Nephrology Service, Reina Sofia University Hospital, Cordoba, Spain
- RETICs-REDinREN (National Institute of Health Carlos III), Madrid, Spain
- * E-mail:
| | - M. Victoria Pendon-Ruiz de Mier
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Reina Sofia University Hospital, University of Cordoba, Cordoba, Spain
- Nephrology Service, Reina Sofia University Hospital, Cordoba, Spain
- RETICs-REDinREN (National Institute of Health Carlos III), Madrid, Spain
| | - M. Luisa Agüera
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Reina Sofia University Hospital, University of Cordoba, Cordoba, Spain
- Nephrology Service, Reina Sofia University Hospital, Cordoba, Spain
- RETICs-REDinREN (National Institute of Health Carlos III), Madrid, Spain
| | - Juan R. Muñoz-Castañeda
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Reina Sofia University Hospital, University of Cordoba, Cordoba, Spain
- Nephrology Service, Reina Sofia University Hospital, Cordoba, Spain
- RETICs-REDinREN (National Institute of Health Carlos III), Madrid, Spain
| | - Sagrario Soriano
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Reina Sofia University Hospital, University of Cordoba, Cordoba, Spain
- Nephrology Service, Reina Sofia University Hospital, Cordoba, Spain
- RETICs-REDinREN (National Institute of Health Carlos III), Madrid, Spain
| | | | - M. Antonia Alvarez-Lara
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Reina Sofia University Hospital, University of Cordoba, Cordoba, Spain
- Nephrology Service, Reina Sofia University Hospital, Cordoba, Spain
- RETICs-REDinREN (National Institute of Health Carlos III), Madrid, Spain
| | - Arnold Felsenfeld
- Wadsworth VA, UCLA, Department of Medicine, Veterans Affairs Greater Los Angeles Healthcare System and the David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California
| | - Pedro Aljama
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Reina Sofia University Hospital, University of Cordoba, Cordoba, Spain
- Nephrology Service, Reina Sofia University Hospital, Cordoba, Spain
- RETICs-REDinREN (National Institute of Health Carlos III), Madrid, Spain
| | - Mariano Rodriguez
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Reina Sofia University Hospital, University of Cordoba, Cordoba, Spain
- Nephrology Service, Reina Sofia University Hospital, Cordoba, Spain
- RETICs-REDinREN (National Institute of Health Carlos III), Madrid, Spain
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Hernando N, Wagner CA. Mechanisms and Regulation of Intestinal Phosphate Absorption. Compr Physiol 2018; 8:1065-1090. [PMID: 29978897 DOI: 10.1002/cphy.c170024] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
States of hypo- and hyperphosphatemia have deleterious consequences including rickets/osteomalacia and renal/cardiovascular disease, respectively. Therefore, the maintenance of appropriate plasma levels of phosphate is an essential requirement for health. This control is executed by the collaborative action of intestine and kidney whose capacities to (re)absorb phosphate are regulated by a number of hormonal and metabolic factors, among them parathyroid hormone, fibroblast growth factor 23, 1,25(OH)2 vitamin D3 , and dietary phosphate. The molecular mechanisms responsible for the transepithelial transport of phosphate across enterocytes are only partially understood. Indeed, whereas renal reabsorption entirely relies on well-characterized active transport mechanisms of phosphate across the renal proximal epithelia, intestinal absorption proceeds via active and passive mechanisms, with the molecular identity of the passive component still unknown. The active absorption of phosphate depends mostly on the activity and expression of the sodium-dependent phosphate cotransporter NaPi-IIb (SLC34A2), which is highly regulated by many of the factors, mentioned earlier. Physiologically, the contribution of NaPi-IIb to the maintenance of phosphate balance appears to be mostly relevant during periods of low phosphate availability. Therefore, its role in individuals living in industrialized societies with high phosphate intake is probably less relevant. Importantly, small increases in plasma phosphate, even within normal range, associate with higher risk of cardiovascular disease. Therefore, therapeutic approaches to treat hyperphosphatemia, including dietary phosphate restriction and phosphate binders, aim at reducing intestinal absorption. Here we review the current state of research in the field. © 2017 American Physiological Society. Compr Physiol 8:1065-1090, 2018.
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Affiliation(s)
- Nati Hernando
- National Center for Competence in Research NCCR Kidney.CH, Institute of Physiology, University Zurich-Irchel, Zurich, Switzerland
| | - Carsten A Wagner
- National Center for Competence in Research NCCR Kidney.CH, Institute of Physiology, University Zurich-Irchel, Zurich, Switzerland
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Friedl C, Zitt E. Role of etelcalcetide in the management of secondary hyperparathyroidism in hemodialysis patients: a review on current data and place in therapy. DRUG DESIGN DEVELOPMENT AND THERAPY 2018; 12:1589-1598. [PMID: 29910605 PMCID: PMC5989700 DOI: 10.2147/dddt.s134103] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Secondary hyperparathyroidism (sHPT) is a frequently occurring severe complication of advanced kidney disease. Its clinical consequences include extraskeletal vascular and valvular calcifications, changes in bone metabolism resulting in renal osteodystrophy, and an increased risk of cardiovascular morbidity and mortality. Calcimimetics are a cornerstone of parathyroid hormone (PTH)-lowering therapy, as confirmed by the recently updated 2017 Kidney Disease: Improving Global Outcomes chronic kidney disease – mineral and bone disorder clinical practice guidelines. Contrary to calcitriol or other vitamin D-receptor activators, calcimimetics reduce PTH without increasing serum-calcium, phosphorus, or FGF23 levels. Etelcalcetide is a new second-generation calcimimetic that has been approved for the treatment of sHPT in adult hemodialysis patients. Whereas the first-generation calcimimetic cinacalcet is taken orally once daily, etelcalcetide is given intravenously thrice weekly at the end of the hemodialysis session. Apart from improving drug adherence, etelcalcetide has proven to be more effective in lowering PTH when compared to cinacalcet, with an acceptable and comparable safety profile. The hope for better gastrointestinal tolerance with intravenous administration did not come true, as etelcalcetide did not significantly mitigate the adverse gastrointestinal effects associated with cinacalcet. Enhanced adherence and strong reductions in PTH, phosphorus, and FGF23 could set the stage for a future large randomized controlled trial to demonstrate that improved biochemical control of mineral metabolism with etelcalcetide in hemodialysis patients translates into cardiovascular and survival benefits and better health-related quality of life.
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Affiliation(s)
- Claudia Friedl
- Department of Internal Medicine, Clinical Division of Nephrology, Medical University of Graz, Graz
| | - Emanuel Zitt
- Department of Internal Medicine III, Nephrology and Dialysis, Feldkirch Academic Teaching Hospital, Feldkirch, Austria
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73
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Kinoshita Y, Fukumoto S. X-Linked Hypophosphatemia and FGF23-Related Hypophosphatemic Diseases: Prospect for New Treatment. Endocr Rev 2018; 39:274-291. [PMID: 29381780 DOI: 10.1210/er.2017-00220] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 01/23/2018] [Indexed: 12/21/2022]
Abstract
Phosphate plays essential roles in many biological processes, and the serum phosphate level is tightly controlled. Chronic hypophosphatemia causes impaired mineralization of the bone matrix and results in rickets and osteomalacia. Fibroblast growth factor 23 (FGF23) is a bone-derived hormone that regulates phosphate metabolism. FGF23 excess induces hypophosphatemia via impaired phosphate reabsorption in the renal proximal tubules and decreased phosphate absorption in the intestines. There are several types of genetic and acquired FGF23-related hypophosphatemic diseases. Among these diseases, X-linked hypophosphatemia (XLH), which is caused by inactivating mutations in the phosphate-regulating endopeptidase homolog, X-linked (PHEX) gene, is the most prevalent form of genetic FGF23-related hypophosphatemic rickets. Another clinically relevant form of FGF23-related hypophosphatemic disease is tumor-induced osteomalacia (TIO), a paraneoplastic syndrome associated with FGF23-producing tumors. A combination of active vitamin D and phosphate salts is the current medical therapy used to treat patients with XLH and inoperative TIO. However, this therapy has certain efficacy- and safety-associated limitations. Several measures to inhibit FGF23 activity have been considered as possible new treatments for FGF23-related hypophosphatemic diseases. In particular, a humanized monoclonal antibody for FGF23 (burosumab) is a promising treatment in patients with XLH and TIO. This review will focus on the phosphate metabolism and the pathogenesis and treatment of FGF23-related hypophosphatemic diseases.
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Affiliation(s)
- Yuka Kinoshita
- Division of Nephrology and Endocrinology, Department of Medicine, The University of Tokyo Hospital, Tokyo, Japan
| | - Seiji Fukumoto
- Fujii Memorial Institute of Medical Sciences, Institute of Advanced Medical Sciences, Tokushima University, Tokushima, Japan
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74
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Durlacher-Betzer K, Hassan A, Levi R, Axelrod J, Silver J, Naveh-Many T. Interleukin-6 contributes to the increase in fibroblast growth factor 23 expression in acute and chronic kidney disease. Kidney Int 2018; 94:315-325. [PMID: 29861060 DOI: 10.1016/j.kint.2018.02.026] [Citation(s) in RCA: 105] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 02/18/2018] [Accepted: 02/22/2018] [Indexed: 12/13/2022]
Abstract
The high serum fibroblast growth factor 23 (FGF23) levels in patients with acute kidney injury (AKI) and chronic kidney disease (CKD) are associated with increased morbidity and mortality. Mice with folic acid-induced AKI had an increase in bone FGF23 mRNA expression together with an increase in serum FGF23 and several circulating cytokines including interleukin-6 (IL-6). Dexamethasone partially prevented the increase in IL-6 and FGF23 in the AKI mice. IL-6 knock-out mice fed an adenine diet to induce CKD failed to increase bone FGF23 mRNA and had a muted increase in serum FGF23 levels, compared with the increases in wild-type mice with CKD. Therefore, IL-6 contributes to the increase in FGF23 observed in CKD. Hydrodynamic tail injection of IL-6/soluble IL-6 receptor (sIL-6R) fusion protein hyper IL-6 (HIL-6) plasmid increased serum FGF23 levels. Circulating sIL-6R levels were increased in both CKD and AKI mice, suggesting that IL-6 increases FGF23 through sIL-6R-mediated trans-signaling. Renal IL-6 mRNA expression was increased in mice with either AKI or CKD, suggesting the kidney is the source for the increased serum IL-6 levels in the uremic state. HIL-6 also increased FGF23 mRNA in calvaria organ cultures and osteoblast-like UMR106 cells in culture, demonstrating a direct effect of IL-6 on FGF23 expression. HIL-6 increased FGF23 promoter activity through STAT3 phosphorylation and its evolutionarily conserved element in the FGF23 promoter. Thus, IL-6 increases FGF23 transcription and contributes to the high levels of serum FGF23 in both acute and chronic kidney disease.
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MESH Headings
- Acute Kidney Injury/blood
- Acute Kidney Injury/chemically induced
- Acute Kidney Injury/drug therapy
- Acute Kidney Injury/immunology
- Adenine/toxicity
- Animals
- Bone and Bones/pathology
- Dexamethasone/therapeutic use
- Disease Models, Animal
- Fibroblast Growth Factor-23
- Fibroblast Growth Factors/blood
- Fibroblast Growth Factors/genetics
- Fibroblast Growth Factors/immunology
- Fibroblast Growth Factors/metabolism
- Folic Acid/toxicity
- Glucocorticoids/therapeutic use
- Humans
- Interleukin-6/blood
- Interleukin-6/genetics
- Interleukin-6/immunology
- Interleukin-6/metabolism
- Kidney/immunology
- Kidney/pathology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Phosphorylation/immunology
- Promoter Regions, Genetic/genetics
- RNA, Messenger/metabolism
- Receptors, Interleukin-6/genetics
- Recombinant Fusion Proteins/administration & dosage
- Recombinant Fusion Proteins/genetics
- Renal Insufficiency, Chronic/blood
- Renal Insufficiency, Chronic/chemically induced
- Renal Insufficiency, Chronic/drug therapy
- Renal Insufficiency, Chronic/immunology
- STAT3 Transcription Factor/metabolism
- Transcription, Genetic/immunology
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Affiliation(s)
- Karina Durlacher-Betzer
- Minerva Center for Calcium and Bone Metabolism, Nephrology Services, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Alia Hassan
- Minerva Center for Calcium and Bone Metabolism, Nephrology Services, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Ronen Levi
- Minerva Center for Calcium and Bone Metabolism, Nephrology Services, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Jonathan Axelrod
- Goldyn Savad Institute of Gene Therapy, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Justin Silver
- Minerva Center for Calcium and Bone Metabolism, Nephrology Services, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Tally Naveh-Many
- Minerva Center for Calcium and Bone Metabolism, Nephrology Services, Hadassah Hebrew University Medical Center, Jerusalem, Israel.
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75
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Kamr AM, Dembek KA, Hildreth BE, Morresey PR, Rathgeber RA, Burns TA, Zaghawa AA, Toribio RE. The FGF-23/klotho axis and its relationship with phosphorus, calcium, vitamin D, PTH, aldosterone, severity of disease, and outcome in hospitalised foals. Equine Vet J 2018; 50:739-746. [PMID: 29660161 DOI: 10.1111/evj.12946] [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: 02/25/2017] [Accepted: 03/30/2018] [Indexed: 01/12/2023]
Abstract
BACKGROUND Fibroblast growth factor-23 (FGF-23) and klotho are key regulators of vitamin D and parathyroid hormone (PTH) synthesis as well as phosphorus and calcium homeostasis; however, information on the FGF-23/klotho axis in healthy and hospitalised foals is lacking. OBJECTIVES The aims of this study were to measure serum FGF-23 and klotho concentrations and determine their association with serum phosphorus, total calcium (TCa), vitamin D metabolite [25(OH)D, 1,25(OH)2 D], PTH, and aldosterone concentrations, disease severity, and mortality in hospitalised foals. STUDY DESIGN Prospective, multicentre, cross-sectional study. METHODS A total of 91 foals ≤72 h old were classified as hospitalised (n = 81; 58 septic; 23 sick non-septic [SNS]) and healthy (n = 10). Blood samples were collected on admission. Hormone concentrations were determined by immunoassays. RESULTS Serum FGF-23, PTH, phosphorus, and aldosterone concentrations were higher while klotho, 25(OH)D, 1,25(OH)2 D, and TCa concentrations were lower in septic and SNS compared to healthy foals (P<0.05). In hospitalised and septic foals, increased FGF-23 and aldosterone concentrations were associated with high phosphorus and PTH but not with TCa and vitamin D metabolite concentrations. Hospitalised foals with the highest FGF-23 and lowest klotho concentrations were more likely to die (odds ratio (OR): 3.3; 95% confidence interval (CI): 1.1-10.3 and OR: 3.1; CI: 1.1-8.0, respectively). MAIN LIMITATIONS Blood gas, ionised calcium, blood culture information not being available for many foals, and use of the sepsis score to classify hospitalised foals. CONCLUSIONS Imbalances in the FGF-23/klotho axis may contribute to mineral dyshomeostasis and disease progression in critically ill foals. Elevated FGF-23 and reduced klotho, together with high phosphorus and PTH concentrations suggests FGF-23 resistance. FGF-23 and klotho are good markers of disease severity and likelihood of mortality in hospitalised foals. Aldosterone may influence phosphorus and PTH dynamics in hospitalised foals. Routine measurement of phosphorus concentrations in sick foals is recommended.
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Affiliation(s)
- A M Kamr
- College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, USA.,Faculty of Veterinary Medicine, University of Sadat City, Sadat City, Egypt
| | - K A Dembek
- College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, USA
| | - B E Hildreth
- College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, USA
| | - P R Morresey
- Rood and Riddle Equine Hospital, Lexington, Kentucky, USA
| | - R A Rathgeber
- Hagyard Equine Medical Institute, Lexington, Kentucky, USA
| | - T A Burns
- College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, USA
| | - A A Zaghawa
- Faculty of Veterinary Medicine, University of Sadat City, Sadat City, Egypt
| | - R E Toribio
- Faculty of Veterinary Medicine, University of Sadat City, Sadat City, Egypt
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76
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Courbebaisse M, Lanske B. Biology of Fibroblast Growth Factor 23: From Physiology to Pathology. Cold Spring Harb Perspect Med 2018; 8:a031260. [PMID: 28778965 PMCID: PMC5932574 DOI: 10.1101/cshperspect.a031260] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Fibroblast growth factor (FGF)23 is a phosphaturic hormone produced by osteocytes and osteoblasts that binds to FGF receptors in the presence of the transmembrane protein αKlotho. FGF23 mainly targets the renal proximal tubule to inhibit calcitriol production and the expression of the sodium/phosphate cotransporters NaPi2a and NaPi2c, thus inhibiting renal phosphate reabsorption. FGF23 also acts on the parathyroid glands to inhibit parathyroid hormone synthesis and secretion. FGF23 regulation involves many systemic and local factors, among them calcitriol, phosphate, and parathyroid hormone. Increased FGF23 is primarily observed in rare acquired or genetic disorders, but chronic kidney disease is associated with a reactional increase in FGF23 to combat hyperphosphatemia. However, high FGF23 levels induce left ventricular hypertrophy (LVH) and are associated with an increased risk of mortality. In this review, we describe FGF23 physiology and the pathological consequences of high or low FGF23 levels.
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Affiliation(s)
- Marie Courbebaisse
- Division of Bone and Mineral Research OMII, Harvard School of Dental Medicine, Boston, Massachusetts 02115
- Paris Descartes University, Paris 75006, France
| | - Beate Lanske
- Division of Bone and Mineral Research OMII, Harvard School of Dental Medicine, Boston, Massachusetts 02115
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114
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77
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Interrelated role of Klotho and calcium-sensing receptor in parathyroid hormone synthesis and parathyroid hyperplasia. Proc Natl Acad Sci U S A 2018; 115:E3749-E3758. [PMID: 29618612 DOI: 10.1073/pnas.1717754115] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The pathogenesis of parathyroid gland hyperplasia is poorly understood, and a better understanding is essential if there is to be improvement over the current strategies for prevention and treatment of secondary hyperparathyroidism. Here we investigate the specific role of Klotho expressed in the parathyroid glands (PTGs) in mediating parathyroid hormone (PTH) and serum calcium homeostasis, as well as the potential interaction between calcium-sensing receptor (CaSR) and Klotho. We generated mouse strains with PTG-specific deletion of Klotho and CaSR and dual deletion of both genes. We show that ablating CaSR in the PTGs increases PTH synthesis, that Klotho has a pivotal role in suppressing PTH in the absence of CaSR, and that CaSR together with Klotho regulates PTH biosynthesis and PTG growth. We utilized the tdTomato gene in our mice to visualize and collect PTGs to reveal an inhibitory function of Klotho on PTG cell proliferation. Chronic hypocalcemia and ex vivo PTG culture demonstrated an independent role for Klotho in mediating PTH secretion. Moreover, we identify an interaction between PTG-expressed CaSR and Klotho. These findings reveal essential and interrelated functions for CaSR and Klotho during parathyroid hyperplasia.
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78
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Abstract
PURPOSE OF REVIEW This review examines the role of fibroblast growth factor-23 (FGF-23) in mineral metabolism, innate immunity and adverse cardiovascular outcomes. RECENT FINDINGS FGF-23, produced by osteocytes in bone, activates FGFR/α-Klotho (α-Kl) complexes in the kidney. The resulting bone-kidney axis coordinates renal phosphate reabsorption with bone mineralization, and creates a counter-regulatory feedback loop to prevent vitamin D toxicity. FGF-23 acts to counter-regulate the effects of vitamin D on innate immunity and cardiovascular responses. FGF-23 is ectopically expressed along with α-Kl in activated macrophages, creating a proinflammatory paracrine signaling pathway that counters the antiinflammatory actions of vitamin D. FGF-23 also inhibits angiotensin-converting enzyme 2 expression and increases sodium reabsorption in the kidney, leading to hypertension and left ventricular hypertrophy. Finally, FGF-23 is purported to cause adverse cardiac and impair neutrophil responses through activation of FGFRs in the absence of α-Kl. Although secreted forms of α-Kl have FGF-23 independent effects, the possibility of α-Kl independent effects of FGF-23 is controversial and requires additional experimental validation. SUMMARY FGF-23 participates in a bone-kidney axis regulating mineral homeostasis, proinflammatory paracrine macrophage signaling pathways, and in a bone-cardio-renal axis regulating hemodynamics that counteract the effects of vitamin D.
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79
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Mace ML, Gravesen E, Nordholm A, Olgaard K, Lewin E. Fibroblast Growth Factor (FGF) 23 Regulates the Plasma Levels of Parathyroid Hormone In Vivo Through the FGF Receptor in Normocalcemia, But Not in Hypocalcemia. Calcif Tissue Int 2018; 102:85-92. [PMID: 29063159 PMCID: PMC5760590 DOI: 10.1007/s00223-017-0333-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 09/22/2017] [Indexed: 01/09/2023]
Abstract
The calcium and phosphate homeostasis is regulated by a complex interplay between parathyroid hormone (PTH), fibroblast growth factor 23 (FGF23), and calcitriol. Experimental studies have demonstrated an inhibitory effect of FG23 on PTH production and secretion; the physiological role of this regulation is however not well understood. Surprisingly, in uremia, concomitantly elevated FGF23 and PTH levels are observed. The parathyroid gland rapidly loses its responsiveness to extracellular calcium in vitro and a functional parathyroid cell line has currently not been established. Therefore, the aim of the present investigation was to study the impact of FGF23 on the Ca2+/PTH relationship in vivo under conditions of normocalcemia and hypocalcemia. Wistar rats were allocated to treatment with intravenous recombinant FGF23 and inhibition of the FGF receptor in the setting of normocalcemia and acute hypocalcemia. We demonstrated that FGF23 rapidly inhibited PTH secretion and that this effect was completely blocked by inhibition of the FGF receptor. Furthermore, inhibition of the FGF receptor by itself significantly increased PTH levels, indicating that FGF23 has a suppressive tonus on the parathyroid gland's PTH secretion. In acute hypocalcemia, there was no effect of either recombinant FGF23 or FGF receptor inhibition on the physiological response to the low ionized calcium levels. In conclusion, FGF23 has an inhibitory tonus on PTH secretion in normocalcemia and signals through the FGF receptor. In acute hypocalcemia, when increased PTH secretion is needed to restore the calcium homeostasis, this inhibitory effect of FGF23 is abolished.
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Affiliation(s)
- Maria L Mace
- Department of Nephrology, Herlev Hospital, University of Copenhagen, 2730, Copenhagen, Denmark
- Department of Nephrology, Rigshospitalet Copenhagen, University of Copenhagen, Copenhagen, Denmark
| | - Eva Gravesen
- Department of Nephrology, Rigshospitalet Copenhagen, University of Copenhagen, Copenhagen, Denmark
| | - Anders Nordholm
- Department of Nephrology, Herlev Hospital, University of Copenhagen, 2730, Copenhagen, Denmark
- Department of Nephrology, Rigshospitalet Copenhagen, University of Copenhagen, Copenhagen, Denmark
| | - Klaus Olgaard
- Department of Nephrology, Rigshospitalet Copenhagen, University of Copenhagen, Copenhagen, Denmark
| | - Ewa Lewin
- Department of Nephrology, Herlev Hospital, University of Copenhagen, 2730, Copenhagen, Denmark.
- Department of Nephrology, Rigshospitalet Copenhagen, University of Copenhagen, Copenhagen, Denmark.
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80
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Onal M, Carlson AH, Thostenson JD, Benkusky NA, Meyer MB, Lee SM, Pike JW. A Novel Distal Enhancer Mediates Inflammation-, PTH-, and Early Onset Murine Kidney Disease-Induced Expression of the Mouse Fgf23 Gene. JBMR Plus 2017. [PMID: 29527594 PMCID: PMC5842943 DOI: 10.1002/jbm4.10023] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Fibroblast growth factor 23 (FGF23) production is regulated by both calciotropic hormones and inflammation. Consistent with this, elevated FGF23 levels are associated with inflammatory markers as well as parathyroid hormone (PTH) in various disease states, including chronic kidney disease (CKD). However, the molecular mechanisms underpinning Fgf23 transcription in response to these regulators are largely unknown. We therefore utilized chromatin immunoprecipitation followed by DNA sequencing (ChIP‐seq) data from an osteocyte cell line to identify potential regulatory regions of the Fgf23 gene. Based on ChIP‐seq analysis of enhancer‐associated histone modifications, including H3K4 methylation and H3K9 acetylation, we discovered several potential enhancers for Fgf23, one of which was located 16kb upstream of the gene's transcriptional start site. Deletion of this putative enhancer from the mouse genome using CRISPR‐Cas9 technology led to lower bone, thymus, and spleen expression of Fgf23 mRNA without altering circulating levels of the intact hormone, although as previously reported, only bone displayed significant basal expression. Nevertheless, lack of the −16kb enhancer blunted FGF23 upregulation in a tissue‐specific manner by the acute inflammatory inducers lipopolysaccharide (LPS), interleukin‐1‐beta (IL‐1β), and tumor necrosis factor‐alpha (TNFα) in bone, non‐osseous tissues, and in circulation. Lack of the −16kb enhancer also inhibited PTH‐induced bone Fgf23 mRNA. Moreover, the absence of this Fgf23 enhancer in an oxalate diet‐induced murine CKD model prevented the early onset induction of osseous, renal, and thymic Fgf23 mRNA levels and led to a significant blunting of elevated circulating intact FGF23 levels. These results suggest that −16kb enhancer mediates the induction of Fgf23 by inflammation and PTH and facilitates the increase in FGF23 expression in a murine model of CKD. As exemplified herein, these Fgf23 enhancer‐deleted mice will provide a unique model in which to study the role of FGF23 expression in inflammatory diseases. © 2017 The Authors. JBMR Plus is published by Wiley Periodicals, Inc. on behalf of the American Society for Bone and Mineral Research.
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Affiliation(s)
- Melda Onal
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA.,Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Alex H Carlson
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Jeff D Thostenson
- Department of Biostatistics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Nancy A Benkusky
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Mark B Meyer
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Seong M Lee
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - J Wesley Pike
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA
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81
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Abstract
Fibroblast growth factor-23 (FGF23) is a bone-derived hormone, mainly produced by osteoblasts and osteocytes in response to increased extracellular phosphate and circulating vitamin D hormone. Endocrine FGF23 signaling requires co-expression of the ubiquitously expressed FGF receptor 1 (FGFR1) and the co-receptor α-Klotho (Klotho). In proximal renal tubules, FGF23 suppresses the membrane expression of the sodium-phosphate cotransporters Npt2a and Npt2c which mediate urinary reabsorption of filtered phosphate. In addition, FGF23 suppresses proximal tubular expression of 1α-hydroxylase, the key enzyme responsible for vitamin D hormone production. In distal renal tubules, FGF23 signaling activates with-no-lysine kinase 4, leading to increased renal tubular reabsorption of calcium and sodium. Therefore, FGF23 is not only a phosphaturic but also a calcium- and sodium-conserving hormone, a finding that may have important implications for the pathophysiology of chronic kidney disease. Besides these endocrine, Klotho-dependent functions of FGF23, FGF23 is also an auto-/paracrine suppressor of tissue-nonspecific alkaline phosphatase transcription via Klotho-independent FGFR3 signaling, leading to local inhibition of mineralization through accumulation of pyrophosphate. In addition, FGF23 may target the heart via an FGFR4-mediated Klotho-independent signaling cascade. Taken together, there is emerging evidence that FGF23 is a pleiotropic hormone, linking bone with several other organ systems.
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MESH Headings
- Autocrine Communication
- Bone and Bones/physiology
- Calcification, Physiologic
- Cardiovascular System
- Fibroblast Growth Factor-23
- Fibroblast Growth Factors/physiology
- Glucuronidase/physiology
- Humans
- Immunomodulation
- Kidney Tubules, Proximal/physiology
- Klotho Proteins
- Paracrine Communication
- Phosphates/physiology
- Receptor, Fibroblast Growth Factor, Type 1/physiology
- Receptor, Fibroblast Growth Factor, Type 3/physiology
- Receptor, Fibroblast Growth Factor, Type 4/physiology
- Sodium-Phosphate Cotransporter Proteins, Type IIa/physiology
- Sodium-Phosphate Cotransporter Proteins, Type IIc/physiology
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Affiliation(s)
- Reinhold G Erben
- 1 Department of Biomedical Sciences, Institute of Physiology, Pathophysiology and Biophysics, University of Veterinary Medicine, Vienna, Austria
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82
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Calcineurin inhibitors regulate fibroblast growth factor 23 (FGF23) synthesis. Naunyn Schmiedebergs Arch Pharmacol 2017; 390:1117-1123. [DOI: 10.1007/s00210-017-1411-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 07/21/2017] [Indexed: 01/06/2023]
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83
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Granjon D, Bonny O, Edwards A. Coupling between phosphate and calcium homeostasis: a mathematical model. Am J Physiol Renal Physiol 2017; 313:F1181-F1199. [PMID: 28747359 DOI: 10.1152/ajprenal.00271.2017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 07/19/2017] [Accepted: 07/19/2017] [Indexed: 12/18/2022] Open
Abstract
We developed a mathematical model of calcium (Ca) and phosphate (PO4) homeostasis in the rat to elucidate the hormonal mechanisms that underlie the regulation of Ca and PO4 balance. The model represents the exchanges of Ca and PO4 between the intestine, plasma, kidneys, bone, and the intracellular compartment, and the formation of Ca-PO4-fetuin-A complexes. It accounts for the regulation of these fluxes by parathyroid hormone (PTH), vitamin D3, fibroblast growth factor 23, and Ca2+-sensing receptors. Our results suggest that the Ca and PO4 homeostatic systems are robust enough to handle small perturbations in the production rate of either PTH or vitamin D3 The model predicts that large perturbations in PTH or vitamin D3 synthesis have a greater impact on the plasma concentration of Ca2+ ([Ca2+]p) than on that of PO4 ([PO4]p); due to negative feedback loops, [PO4]p does not consistently increase when the production rate of PTH or vitamin D3 is decreased. Our results also suggest that, following a large PO4 infusion, the rapidly exchangeable pool in bone acts as a fast, transient storage PO4 compartment (on the order of minutes), whereas the intracellular pool is able to store greater amounts of PO4 over several hours. Moreover, a large PO4 infusion rapidly lowers [Ca2+]p owing to the formation of CaPO4 complexes. A large Ca infusion, however, has a small impact on [PO4]p, since a significant fraction of Ca binds to albumin. This mathematical model is the first to include all major regulatory factors of Ca and PO4 homeostasis.
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Affiliation(s)
- David Granjon
- Sorbonne Universités, UPMC University of Paris 06, Université Paris Descartes, Sorbonne Paris Cité, INSERM UMRS 1138, CNRS ERL 8228, Centre de Recherche des Cordeliers, Paris, France.,Department of Pharmacology and Toxicology, University of Lausanne, and Service of Nephrology, Lausanne University Hospital, Lausanne, Switzerland; and
| | - Olivier Bonny
- Department of Pharmacology and Toxicology, University of Lausanne, and Service of Nephrology, Lausanne University Hospital, Lausanne, Switzerland; and
| | - Aurélie Edwards
- Sorbonne Universités, UPMC University of Paris 06, Université Paris Descartes, Sorbonne Paris Cité, INSERM UMRS 1138, CNRS ERL 8228, Centre de Recherche des Cordeliers, Paris, France; .,Department of Biomedical Engineering, Boston University, Boston, Massachusetts
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84
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Wesseling-Perry K, Mäkitie RE, Välimäki VV, Laine T, Laine CM, Välimäki MJ, Pereira RC, Mäkitie O. Osteocyte Protein Expression Is Altered in Low-Turnover Osteoporosis Caused by Mutations in WNT1 and PLS3. J Clin Endocrinol Metab 2017; 102:2340-2348. [PMID: 28379384 PMCID: PMC5505188 DOI: 10.1210/jc.2017-00099] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 03/29/2017] [Indexed: 01/20/2023]
Abstract
CONTEXT Osteocytes express proteins that regulate bone remodeling and mineralization. OBJECTIVE To evaluate the relationship between osteocyte-specific protein expression and bone histology in patients with monogenic osteoporosis due to wingless integration site 1 (WNT1) or plastin 3 (PLS3) mutations. DESIGN AND SETTING Cross-sectional cohort study at a university hospital. PARTICIPANTS Six patients (four males; ages: 14 to 72 years) with a heterozygous WNT1 mutation and five patients (four males; ages: 9 to 70 years) with a heterozygous/hemizygous PLS3 mutation. METHODS AND MAIN OUTCOME MEASURES Immunohistochemistry was performed for fibroblast growth factor 23 (FGF23), dentin matrix protein 1 (DMP1), sclerostin, and phosphorylated (phospho-)β-catenin in iliac crest samples and compared with bone histomorphometry. RESULTS FGF23 expression in WNT1 patients was 243% that observed in PLS3 patients (P < 0.01). DMP1, sclerostin, and phospho-β-catenin expression did not differ between groups. Serum phosphate correlated inversely with FGF23 expression (r = -0.79, P = 0.01) and serum ionized calcium correlated inversely with sclerostin expression (r = -0.60, P = 0.05). Phospho-β-catenin expression correlated inversely with DMP1 expression (r = -0.88, P < 0.001), osteoid volume/bone volume (r = -0.68, P = 0.02), and bone formation rate (r = -0.78, P < 0.01). FGF23 expression did not correlate with DMP1 expression, sclerostin expression, or bone histomorphometry. Marrow adiposity was higher in WNT1 than in PLS3 patients (P = 0.04). CONCLUSIONS Mutations that disrupt WNT signaling and osteocytic mechanosensing affect osteocyte protein expression. Abnormal osteocyte function may play a role in the pathogenesis of monogenetic forms of osteoporosis.
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Affiliation(s)
- Katherine Wesseling-Perry
- Department of Pediatrics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California 90095
| | - Riikka E. Mäkitie
- Folkhälsan Institute of Genetics, University of Helsinki, 00014 Helsinki, Finland
| | - Ville-Valtteri Välimäki
- Department of Orthopedics and Traumatology, Helsinki University Central Hospital and Helsinki University, Jorvi Hospital, 02740 Espoo, Finland
| | - Tero Laine
- Department of Orthopedics, Institute of Clinical Sciences, Sahlgrenska University Hospital and University of Gothenburg, 41345 Gothenburg, Sweden
| | - Christine M. Laine
- Children’s Hospital, University of Helsinki and Helsinki University Hospital, 00014 Helsinki, Finland
- Department of Endocrinology, Institute of Medicine, Sahlgrenska University Hospital and University of Gothenburg, 41345 Gothenburg, Sweden
| | - Matti J. Välimäki
- Division of Endocrinology, Department of Medicine, Helsinki University Central Hospital, 00029 Helsinki, Finland
| | - Renata C. Pereira
- Department of Pediatrics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California 90095
| | - Outi Mäkitie
- Folkhälsan Institute of Genetics, University of Helsinki, 00014 Helsinki, Finland
- Children’s Hospital, University of Helsinki and Helsinki University Hospital, 00014 Helsinki, Finland
- Department of Molecular Medicine and Surgery, Karolinska Institutet, 17176 Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, 17176 Stockholm, Sweden
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85
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Hruska KA, Sugatani T, Agapova O, Fang Y. The chronic kidney disease - Mineral bone disorder (CKD-MBD): Advances in pathophysiology. Bone 2017; 100:80-86. [PMID: 28119179 PMCID: PMC5502716 DOI: 10.1016/j.bone.2017.01.023] [Citation(s) in RCA: 118] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 01/19/2017] [Accepted: 01/20/2017] [Indexed: 01/01/2023]
Abstract
The causes of excess cardiovascular mortality associated with chronic kidney disease (CKD) have been attributed in part to the CKD-mineral bone disorder syndrome (CKD-MBD), wherein, novel cardiovascular risk factors have been identified. New advances in the causes of the CKD-MBD are discussed in this review. They demonstrate that repair and disease processes in the kidneys release factors to the circulation that cause the systemic complications of CKD. The discovery of WNT inhibitors, especially Dickkopf 1 (Dkk1), produced during renal repair as participating in the pathogenesis of the vascular and skeletal components of the CKD-MBD implied that additional pathogenic factors are critical. This lead to the discovery that activin A is a second renal repair factor circulating in increased levels during CKD. Activin A derives from peritubular myofibroblasts of diseased kidneys, wherein it stimulates fibrosis, and decreases tubular klotho expression. Activin A binds to the type 2 activin A receptor, ActRIIA, which is variably affected by CKD in the vasculature. In diabetic/atherosclerotic aortas, specifically in vascular smooth muscle cells (VSMC), ActRIIA signaling is inhibited and contributes to CKD induced VSMC dedifferentiation, osteogenic transition and neointimal atherosclerotic calcification. In nondiabetic/nonatherosclerotic aortas, CKD increases VSMC ActRIIA signaling, and vascular fibroblast signaling causing the latter to undergo osteogenic transition and stimulate vascular calcification. In both vascular situations, a ligand trap for ActRIIA prevented vascular calcification. In the skeleton, activin A is responsible for CKD stimulation of osteoclastogenesis and bone remodeling increasing bone turnover. These studies demonstrate that circulating renal repair and injury factors are causal of the CKD-MBD and CKD associated cardiovascular disease.
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Affiliation(s)
- Keith A Hruska
- Department of Pediatrics, Nephrology, Washington University Saint Louis, MO, United States; Departments of Medicine, Washington University Saint Louis, MO, United States; Department of Cell Biology, Washington University Saint Louis, MO, United States.
| | - Toshifumi Sugatani
- Department of Pediatrics, Nephrology, Washington University Saint Louis, MO, United States
| | - Olga Agapova
- Department of Pediatrics, Nephrology, Washington University Saint Louis, MO, United States
| | - Yifu Fang
- Department of Pediatrics, Nephrology, Washington University Saint Louis, MO, United States
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86
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Friedl C, Zitt E. Vitamin D prohormone in the treatment of secondary hyperparathyroidism in patients with chronic kidney disease. Int J Nephrol Renovasc Dis 2017; 10:109-122. [PMID: 28546765 PMCID: PMC5436758 DOI: 10.2147/ijnrd.s97637] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Secondary hyperparathyroidism (sHPT) represents the adaptive and very often, finally, maladaptive response of the organism to control the disturbed homeostasis of calcium, phosphorus, and vitamin D metabolism caused by declining renal function in chronic kidney disease (CKD). sHPT leads to cardiovascular and extravascular calcifications and is directly linked to an increased risk of cardiovascular morbidity and mortality as well as excess all-cause mortality. Vitamin D plays an important role in the development of sHPT. CKD patients are characterized by a high prevalence of hypovitaminosis D. Supplementation with both vitamin D prohormones cholecalciferol and ergocalciferol enables the achievement and maintenance of a normal vitamin D status when given in adequate doses over an appropriate treatment period. In patients with earlier stages of CKD, sHPT is influenced by and can be successfully treated with vitamin D prohormone supplementation, whereas in patients with very late stages of CKD and those requiring dialysis, treatment with prohormones seems to be of limited efficacy. This review gives an overview of the pathogenesis of sHPT, summarizes vitamin D metabolism, and discusses the existing literature regarding the role of vitamin D prohormone in the treatment of sHPT in patients with CKD.
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Affiliation(s)
- Claudia Friedl
- Department of Internal Medicine, Clinical Division of Nephrology, Medical University of Graz, Graz
| | - Emanuel Zitt
- Department of Nephrology and Dialysis, Feldkirch Academic Teaching Hospital, Feldkirch, Austria
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87
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Knab VM, Corbin B, Andrukhova O, Hum JM, Ni P, Rabadi S, Maeda A, White KE, Erben RG, Jüppner H, Christov M. Acute Parathyroid Hormone Injection Increases C-Terminal but Not Intact Fibroblast Growth Factor 23 Levels. Endocrinology 2017; 158:1130-1139. [PMID: 28324013 PMCID: PMC5460828 DOI: 10.1210/en.2016-1451] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2016] [Accepted: 01/12/2017] [Indexed: 12/18/2022]
Abstract
The acute effects of parathyroid hormone (PTH) on fibroblast growth factor 23 (FGF23) in vivo are not well understood. After a single subcutaneous PTH (1-34) injection (50 nmol/kg) in mice, FGF23 levels were assessed in plasma using assays that measure either intact alone (iFGF23) or intact/C-terminal FGF23 (cFGF23). Furthermore, FGF23 messenger RNA (mRNA) and protein levels were assessed in bone. In addition, we examined the effects of PTH treatment on FGF23 production in vitro using differentiated calvarial osteocyte-like cells. cFGF23 levels increased by three- to fivefold within 2 hours following PTH injection, which returned to baseline by 4 hours. In contrast, iFGF23 levels remained unchanged for the first 2 hours, yet declined to ∼60% by 6 hours and remained suppressed before returning to baseline after 24 hours. Using homozygous mice for an autosomal dominant hypophosphatemic rickets-FGF23 mutation or animals treated with a furin inhibitor, we showed that cFGF23 and iFGF23 levels increased equivalently after PTH injection. These findings are consistent with increased FGF23 production in bone, yet rapid cleavage of the secreted intact protein. Using primary osteocyte-like cell cultures, we showed that PTH increased FGF23 mRNA expression through cyclic adenosine monophosphate/protein kinase A, but not inositol triphosphate/protein kinase C signaling; PTH also increased furin protein levels. In conclusion, PTH injection rapidly increases FGF23 production in bone in vivo and in vitro. However, iFGF23 is rapidly degraded. At later time points through an unidentified mechanism, a sustained decrease in FGF23 production occurs.
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Affiliation(s)
- Vanessa M Knab
- Department of Medicine, Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts 02114
- Department of Biomedical Sciences, University of Veterinary Medicine, A-1210 Vienna, Austria
| | - Braden Corbin
- Department of Medicine, Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Olena Andrukhova
- Department of Biomedical Sciences, University of Veterinary Medicine, A-1210 Vienna, Austria
| | - Julia M Hum
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Pu Ni
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Seham Rabadi
- Department of Medicine, New York Medical College, Valhalla, New York 10595
| | - Akira Maeda
- Department of Medicine, Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Kenneth E White
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Reinhold G Erben
- Department of Biomedical Sciences, University of Veterinary Medicine, A-1210 Vienna, Austria
| | - Harald Jüppner
- Department of Medicine, Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Marta Christov
- Department of Medicine, Endocrine Unit, Massachusetts General Hospital, Boston, Massachusetts 02114
- Department of Medicine, New York Medical College, Valhalla, New York 10595
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88
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Bastepe M, Turan S, He Q. Heterotrimeric G proteins in the control of parathyroid hormone actions. J Mol Endocrinol 2017; 58:R203-R224. [PMID: 28363951 PMCID: PMC5650080 DOI: 10.1530/jme-16-0221] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 02/17/2017] [Indexed: 12/17/2022]
Abstract
Parathyroid hormone (PTH) is a key regulator of skeletal physiology and calcium and phosphate homeostasis. It acts on bone and kidney to stimulate bone turnover, increase the circulating levels of 1,25 dihydroxyvitamin D and calcium and inhibit the reabsorption of phosphate from the glomerular filtrate. Dysregulated PTH actions contribute to or are the cause of several endocrine disorders. This calciotropic hormone exerts its actions via binding to the PTH/PTH-related peptide receptor (PTH1R), which couples to multiple heterotrimeric G proteins, including Gs and Gq/11 Genetic mutations affecting the activity or expression of the alpha-subunit of Gs, encoded by the GNAS complex locus, are responsible for several human diseases for which the clinical findings result, at least partly, from aberrant PTH signaling. Here, we review the bone and renal actions of PTH with respect to the different signaling pathways downstream of these G proteins, as well as the disorders caused by GNAS mutations.
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Affiliation(s)
- Murat Bastepe
- Endocrine UnitDepartment of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Serap Turan
- Department of Pediatric EndocrinologyMarmara University School of Medicine, Istanbul, Turkey
| | - Qing He
- Endocrine UnitDepartment of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
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89
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Nguyen-Yamamoto L, Karaplis AC, St-Arnaud R, Goltzman D. Fibroblast Growth Factor 23 Regulation by Systemic and Local Osteoblast-Synthesized 1,25-Dihydroxyvitamin D. J Am Soc Nephrol 2017; 28:586-597. [PMID: 27535551 PMCID: PMC5280015 DOI: 10.1681/asn.2016010066] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 07/10/2016] [Indexed: 01/02/2023] Open
Abstract
Circulating levels of fibroblast growth factor 23 (FGF23) increase during the early stages of kidney disease, but the underlying mechanism remains incompletely characterized. We investigated the role of vitamin D metabolites in regulating intact FGF23 production in genetically modified mice without and with adenine-induced uremia. Exogenous calcitriol (1,25-dihydroxyvitamin D) and high circulating levels of calcidiol (25-hydroxyvitamin D) each increased serum FGF23 levels in wild-type mice and in mice with global deficiency of the Cyp27b1 gene encoding 25-hydroxyvitamin D 1-α-hydroxylase, which produces 1,25-hydroxyvitamin D. Compared with wild-type mice, normal, or uremic mice lacking Cyp27b1 had lower levels of serum FGF23, despite having high concentrations of parathyroid hormone, but administration of exogenous 1,25-dihydroxyvitamin D increased FGF23 levels. Furthermore, raising serum calcium levels in Cyp27b1-depleted mice directly increased FGF23 levels and indirectly enhanced the action of ambient vitamin D metabolites via the vitamin D receptor. In chromatin immunoprecipitation assays, 25-hydroxyvitamin D promoted binding of the vitamin D receptor and retinoid X receptor to the promoters of osteoblastic target genes. Conditional osteoblastic deletion of Cyp27b1 caused lower serum FGF23 levels, despite normal circulating levels of vitamin D metabolites. In adenine-induced uremia, only a modest increase in serum FGF23 levels occurred in mice with osteoblastic deletion of Cyp27b1 (12-fold) compared with a large increase (58-fold) in wild-type mice. Therefore, in addition to the direct effect of high circulating concentrations of 25-hydroxyvitamin D, local osteoblastic conversion of 25-hydroxyvitamin D to 1,25-dihydroxyvitamin D appears to be an important positive regulator of FGF23 production, particularly in uremia.
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Affiliation(s)
| | - Andrew C Karaplis
- Department of Medicine, Sir Mortimer B. Davis Jewish General Hospital, McGill University, Montreal, Canada; and
| | - Rene St-Arnaud
- Departments of Medicine
- Surgery, and
- Human Genetics, and
- Research Centre, Shriners Hospital for Children, Montreal, Canada
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90
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Yamada S, Tsuruya K, Tokumoto M, Yoshida H, Tatsumoto N, Ooboshi H, Kitazono T. Total Phosphate Elimination is Negatively Associated With Increased Serum Fibroblast Growth Factor 23 Levels in Patients who Undergo Peritoneal Dialysis. Ther Apher Dial 2017; 21:71-78. [PMID: 28078749 DOI: 10.1111/1744-9987.12478] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 06/05/2016] [Accepted: 06/30/2016] [Indexed: 12/15/2022]
Abstract
As fibroblast growth factor 23 (FGF23) has been shown to induce cardiovascular disease directly in patients with chronic kidney disease, identification of factors and treatments that can modulate serum FGF23 (sFGF23) level is clinically important. This retrospective longitudinal study investigated factors that modulate sFGF23 in 49 patients who underwent peritoneal dialysis (PD). sFGF23 ratio (sFGF23 at 18 months/baseline sFGF23) was used as an indicator of changes in sFGF23 level. Total phosphate elimination was the sum of both renal phosphate excretion and dialysate phosphate elimination. In multivariate analysis, log sFGF23 ratio was associated negatively with total phosphate elimination and the use of cinacalcet at baseline, and positively with the use of vitamin D receptor activators at baseline, even after adjusting for potential confounding factors. Our study indicates that maintaining phosphate elimination can prevent increased sFGF23, thereby preventing cardiovascular events in patients who undergo PD.
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Affiliation(s)
- Shunsuke Yamada
- Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Higashi-ku, Fukuoka, Japan.,Department of Internal Medicine, Fukuoka Dental College, Sawara-ku, Fukuoka, Japan
| | - Kazuhiko Tsuruya
- Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Higashi-ku, Fukuoka, Japan.,Department of Integrated Therapy for Chronic Kidney Disease, Graduate School of Medical Sciences, Kyushu University, Higashi-ku, Fukuoka, Japan
| | - Masanori Tokumoto
- Department of Internal Medicine, Fukuoka Dental College, Sawara-ku, Fukuoka, Japan
| | - Hisako Yoshida
- Department of Integrated Therapy for Chronic Kidney Disease, Graduate School of Medical Sciences, Kyushu University, Higashi-ku, Fukuoka, Japan
| | - Narihito Tatsumoto
- Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Higashi-ku, Fukuoka, Japan
| | - Hiroaki Ooboshi
- Department of Internal Medicine, Fukuoka Dental College, Sawara-ku, Fukuoka, Japan
| | - Takanari Kitazono
- Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Higashi-ku, Fukuoka, Japan
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91
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Kuczera P, Adamczak M, Wiecek A. Fibroblast Growth Factor-23-A Potential Uremic Toxin. Toxins (Basel) 2016; 8:toxins8120369. [PMID: 27941640 PMCID: PMC5198563 DOI: 10.3390/toxins8120369] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 11/30/2016] [Accepted: 12/01/2016] [Indexed: 12/25/2022] Open
Abstract
Fibroblast growth factor-23 (FGF23) is a circulating member of the FGF family produced mainly by the osteocytes and osteoblasts that can act as a hormone. The main action of FGF23 is to lower phosphatemia via the reduction of urinary phosphate reabsorption and the decrease of 1,25(OH)2-D generation in the kidney. In the course of chronic kidney disease (CKD), plasma FGF23 concentration rises early, most probably to compensate the inability of the deteriorating kidneys to excrete an adequate amount of phosphate. However, this comes at the cost of FGF23-related target organ toxicity. Results of clinical studies suggest that elevated plasma FGF23 concentration is independently associated with the increased risk of CKD progression, occurrence of cardio-vascular complications, and mortality in different stages of CKD. FGF23 also contributes to cardiomyocyte hypertrophy, vascular calcification, and endothelial dysfunction. The impact of FGF23 on heart muscle is not dependent on Klotho, but rather on the PLCγ–calcineurin–NFAT (nuclear factor of activated T-cells) pathway. Among the factors increasing plasma FGF23 concentration, active vitamin D analogues play a significant role. Additionally, inflammation and iron deficiency can contribute to the increase of plasma FGF23. Among the factors decreasing plasma FGF23, dietary phosphate restriction, some intestinal phosphate binders, cinacalcet (and other calcimimetics), and nicotinamide can be enumerated. Anti-FGF23 antibodies have also recently been developed to inhibit the action of FGF23 in target organs. Still, the best way to normalize plasma FGF23 in maintenance hemodialysis patients is restoring kidney function by successful kidney transplantation.
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Affiliation(s)
- Piotr Kuczera
- Department of Nephrology, Transplantation and Internal Medicine, Medical University of Silesia, Katowice 40-027, Poland.
| | - Marcin Adamczak
- Department of Nephrology, Transplantation and Internal Medicine, Medical University of Silesia, Katowice 40-027, Poland.
| | - Andrzej Wiecek
- Department of Nephrology, Transplantation and Internal Medicine, Medical University of Silesia, Katowice 40-027, Poland.
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92
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Affiliation(s)
- Tally Naveh-Many
- Minerva Center for Calcium and Bone Metabolism, Nephrology Services, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Justin Silver
- Minerva Center for Calcium and Bone Metabolism, Nephrology Services, Hadassah Hebrew University Medical Center, Jerusalem, Israel
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93
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Abstract
Fibroblast growth factor-23 (FGF23) is a bone-derived hormone known to suppress phosphate reabsorption and vitamin D hormone production in the kidney. Klotho was originally discovered as an anti-aging factor, but the functional role of Klotho is still a controversial issue. Three major functions have been proposed, a hormonal function of soluble Klotho, an enzymatic function as glycosidase, and the function as an obligatory co-receptor for FGF23 signaling. The purpose of this review is to highlight the recent advances in the area of FGF23 and Klotho signaling in the kidney, in the parathyroid gland, in the cardiovascular system, in bone, and in the central nervous system. During recent years, major new functions of FGF23 and Klotho have been discovered in these organ systems. Based on these novel findings, FGF23 has emerged as a pleiotropic endocrine and auto-/paracrine factor influencing not only mineral metabolism but also cardiovascular function.
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94
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Jeong S, Kim IW, Oh KH, Han N, Joo KW, Kim HJ, Oh JM. Pharmacogenetic analysis of cinacalcet response in secondary hyperparathyroidism patients. DRUG DESIGN DEVELOPMENT AND THERAPY 2016; 10:2211-25. [PMID: 27468225 PMCID: PMC4944925 DOI: 10.2147/dddt.s103370] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Background Secondary hyperparathyroidism (SHPT) is one of the major risk factors of morbidity and mortality in end-stage renal disease. Cinacalcet effectively controls SHPT without causing hypercalcemia and hyperphosphatemia. However, there is significant inter-individual response variance to cinacalcet treatment. Therefore, we aimed to evaluate the genetic effects related with parathyroid hormone regulation as factors for cinacalcet response variance. Methods Patients with a diagnosis of SHPT based on intact parathyroid hormone (iPTH) >300 pg/mL on dialysis were included in this study. They were over 18 years and have been treated by cinacalcet for more than 3 months. Responders and nonresponders were grouped by the serum iPTH changes. Twenty-four single nucleotide polymorphisms of CASR, VDR, FGFR1, KL, ALPL, RGS14, NR4A2, and PTHLH genes were selected for the pharmacogenetic analysis. Results After adjusting for age, sex, and calcium level, CASR rs1042636 (odds ratio [OR]: 0.066, P=0.027) and rs1802757 (OR: 10.532, P=0.042) were associated with cinacalcet response. The association of haplotypes of CASR rs1042636, rs10190, and rs1802757; GCC (OR: 0.355, P=0.015); and ATT (OR: 2.769, P=0.014) with cinacalcet response was also significant. Conclusion We obtained supporting information of the associations between cinacalcet response and CASR polymorphisms. CASR single nucleotide polymorphisms (SNPs) rs1802757, rs1042636, and haplotypes of rs1042636, rs10190, and rs1802757 were significantly associated with cinacalcet response variance.
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Affiliation(s)
- Sohyun Jeong
- College of Pharmacy, Research Institute of Pharmaceutical Sciences, Seoul National University
| | - In-Wha Kim
- College of Pharmacy, Research Institute of Pharmaceutical Sciences, Seoul National University
| | - Kook-Hwan Oh
- Department of Internal Medicine, Division of Nephrology, Seoul National University Hospital, Seoul, Korea
| | - Nayoung Han
- College of Pharmacy, Research Institute of Pharmaceutical Sciences, Seoul National University
| | - Kwon Wook Joo
- Department of Internal Medicine, Division of Nephrology, Seoul National University Hospital, Seoul, Korea
| | - Hyo Jin Kim
- Department of Internal Medicine, Division of Nephrology, Seoul National University Hospital, Seoul, Korea
| | - Jung Mi Oh
- College of Pharmacy, Research Institute of Pharmaceutical Sciences, Seoul National University
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95
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Abstract
The last 25 years have been characterized by dramatic improvements in short-term patient and allograft survival after kidney transplantation. Long-term patient and allograft survival remains limited by cardiovascular disease and chronic allograft injury, among other factors. Cardiovascular disease remains a significant contributor to mortality in native chronic kidney disease as well as cardiovascular mortality in chronic kidney disease more than doubles that of the general population. The chronic kidney disease (CKD)-mineral bone disorder (MBD) is a syndrome recently coined to embody the biochemical, skeletal, and cardiovascular pathophysiology that results from disrupting the complex systems biology between the kidney, skeleton, and cardiovascular system in native and transplant kidney disease. The CKD-MBD is a unique kidney disease-specific syndrome containing novel cardiovascular risk factors, with an impact reaching far beyond traditional notions of renal osteodystrophy and hyperparathyroidism. This overview reviews current knowledge of the pathophysiology of the CKD-MBD, including emerging concepts surrounding the importance of circulating pathogenic factors released from the injured kidney that directly cause cardiovascular disease in native and transplant chronic kidney disease, with potential application to mechanisms of chronic allograft injury and vasculopathy.
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96
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Abstract
Maintenance of a normal serum phosphate level depends on absorption in the gut, reabsorption and excretion by the kidney, and the flux between the extracellular and skeletal pools. Phosphate homeostasis is a coordinated, complex system of crosstalk between the bone, intestine, kidney, and parathyroid gland. Dysfunction of this system has serious clinical consequences in healthy individuals and those with conditions, such as CKD, in which hyperphosphatemia is associated with increased risks of cardiovascular morbidity and mortality. The last half-century of renal research has helped define the contribution of the parathyroid hormone, calcitriol, fibroblast growth factor 23, and Klotho in the regulation of phosphate. However, despite new discoveries and insights gained during this time, what remains unchanged is the recognition that phosphate retention is the initiating factor for the development of many of the complications observed in CKD, namely secondary hyperparathyroidism and bone and cardiovascular diseases. Controlling phosphate load remains the primary goal in the treatment of CKD. This review discusses the clinical effects of dysregulated phosphate metabolism, particularly in CKD, and its association with cardiovascular disease. The importance of early control of phosphate load in the treatment of CKD is emphasized, and the latest research in the treatment of phosphate retention is discussed.
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Affiliation(s)
- Cynthia S Ritter
- Renal Division, Washington University School of Medicine, St. Louis, Missouri
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97
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Salanova Villanueva L, Sánchez González C, Sánchez Tomero JA, Aguilera A, Ortega Junco E. Bone mineral disorder in chronic kidney disease: Klotho and FGF23; cardiovascular implications. Nefrologia 2016; 36:368-75. [PMID: 27118192 DOI: 10.1016/j.nefro.2016.01.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Revised: 12/17/2015] [Accepted: 01/02/2016] [Indexed: 12/30/2022] Open
Abstract
Cardiovascular factors are one of the main causes of morbidity and mortality in patients with chronic kidney disease. Bone mineral metabolism disorders and inflammation are pathological conditions that involve increased cardiovascular risk in chronic kidney disease. The cardiovascular risk involvement of bone mineral metabolism classical biochemical parameters such as phosphorus, calcium, vitamin D and PTH is well known. The newest markers, FGF23 and klotho, could also be implicated in cardiovascular disease.
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98
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Carrillo-López N, Panizo S, Alonso-Montes C, Román-García P, Rodríguez I, Martínez-Salgado C, Dusso AS, Naves M, Cannata-Andía JB. Direct inhibition of osteoblastic Wnt pathway by fibroblast growth factor 23 contributes to bone loss in chronic kidney disease. Kidney Int 2016; 90:77-89. [PMID: 27165819 DOI: 10.1016/j.kint.2016.01.024] [Citation(s) in RCA: 99] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 12/23/2015] [Accepted: 01/14/2016] [Indexed: 12/20/2022]
Abstract
Bone loss and increased fractures are common complications in chronic kidney disease. Because Wnt pathway activation is essential for normal bone mineralization, we assessed whether Wnt inhibition contributes to high-phosphorus-induced mineralization defects in uremic rats. By week 20 after 7/8 nephrectomy, rats fed a high-phosphorus diet had the expected high serum creatinine, phosphorus, parathyroid hormone, and fibroblast growth factor 23 (FGF23) levels and low serum calcium. There was a 15% reduction in tibial mineral density and a doubling of bone cortical porosity compared to uremic rats fed a normal-phosphorus diet. The decreases in tibial mineral density were preceded by time-dependent increments in gene expression of bone formation (Osteocalcin and Runx2) and resorption (Cathepsin K) markers, which paralleled elevations in gene expression of the Wnt inhibitors Sfrp1 and Dkk1 in bone. Similar elevations of Wnt inhibitors plus an increased phospho-β-catenin/β-catenin ratio occurred upon exposure of the osteoblast cell line UMR106-01 either to uremic serum or to the combination of parathyroid hormone, FGF23, and soluble Klotho, at levels present in uremic serum. Strikingly, while osteoblast exposure to parathyroid hormone suppressed the expression of Wnt inhibitors, FGF23 directly inhibited the osteoblastic Wnt pathway through a soluble Klotho/MAPK-mediated process that required Dkk1 induction. Thus, the induction of Dkk1 by FGF23/soluble Klotho in osteoblasts inactivates Wnt/β-catenin signaling. This provides a novel autocrine/paracrine mechanism for the adverse impact of high FGF23 levels on bone in chronic kidney disease.
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Affiliation(s)
- Natalia Carrillo-López
- Bone and Mineral Research Unit, Instituto Reina Sofía de Investigación Nefrológica, REDinREN del ISCIII, Hospital Universitario Central de Asturias, Oviedo, Asturias, Spain
| | - Sara Panizo
- Bone and Mineral Research Unit, Instituto Reina Sofía de Investigación Nefrológica, REDinREN del ISCIII, Hospital Universitario Central de Asturias, Oviedo, Asturias, Spain
| | - Cristina Alonso-Montes
- Bone and Mineral Research Unit, Instituto Reina Sofía de Investigación Nefrológica, REDinREN del ISCIII, Hospital Universitario Central de Asturias, Oviedo, Asturias, Spain
| | - Pablo Román-García
- Bone and Mineral Research Unit, Instituto Reina Sofía de Investigación Nefrológica, REDinREN del ISCIII, Hospital Universitario Central de Asturias, Oviedo, Asturias, Spain
| | - Isabel Rodríguez
- Bone and Mineral Research Unit, Instituto Reina Sofía de Investigación Nefrológica, REDinREN del ISCIII, Hospital Universitario Central de Asturias, Oviedo, Asturias, Spain
| | - Carlos Martínez-Salgado
- Instituto de Estudios de Ciencias de la Salud de Castilla y León (IECSCYL)-Instituto Biosanitario de Salamanca (IBSAL), Hospital Universitario de Salamanca, Salamanca, Spain
| | - Adriana S Dusso
- Bone and Mineral Research Unit, Instituto Reina Sofía de Investigación Nefrológica, REDinREN del ISCIII, Hospital Universitario Central de Asturias, Oviedo, Asturias, Spain
| | - Manuel Naves
- Bone and Mineral Research Unit, Instituto Reina Sofía de Investigación Nefrológica, REDinREN del ISCIII, Hospital Universitario Central de Asturias, Oviedo, Asturias, Spain
| | - Jorge B Cannata-Andía
- Bone and Mineral Research Unit, Instituto Reina Sofía de Investigación Nefrológica, REDinREN del ISCIII, Hospital Universitario Central de Asturias, Oviedo, Asturias, Spain; Departmento de Medicina, Universidad de Oviedo, Oviedo, Asturias, Spain.
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99
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Abstract
The regulation of phosphate metabolism as an influence on bone homeostasis is profound. Recent advances in understanding the systemic control of Fibroblast growth factor-23 (FGF23) has uncovered novel effectors of endocrine feedback loops for calcium, phosphate, and vitamin D balance that interact with 'traditional' feedback loops for mineral metabolism. Not only are these findings re-shaping research studying phosphate handling and skeletal interactions, they have provided new therapeutic interventions. Emerging data support that the control of FGF23 production in bone and its circulating concentrations is a multi-layered process, with some influences affecting FGF23 transcription and some post-translational modification of the secreted, bioactive protein. Additionally, the actions of FGF23 on its target tissues via its co-receptor αKlotho, are subject to regulatory events just coming to light. The recent findings of systemic influences on circulating FGF23 and the downstream manifestations on bone homeostasis will be reviewed herein.
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Affiliation(s)
- Erica L Clinkenbeard
- Department of Medical and Molecular Genetics, Division of Molecular Genetics and Gene Therapy, Indiana University School of Medicine, Indianapolis, IN 46202
| | - Kenneth E White
- Department of Medical and Molecular Genetics, Division of Molecular Genetics and Gene Therapy, Indiana University School of Medicine, Indianapolis, IN 46202
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100
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Hassan A, Durlacher K, Silver J, Naveh-Many T, Levi R. The fibroblast growth factor receptor mediates the increased FGF23 expression in acute and chronic uremia. Am J Physiol Renal Physiol 2016; 310:F217-21. [DOI: 10.1152/ajprenal.00332.2015] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 08/20/2015] [Indexed: 11/22/2022] Open
Abstract
Serum FGF23 is markedly elevated in chronic kidney disease and has been associated with poor long-term outcomes. FGF23 expression is increased by activation of the FGF receptor 1 (FGFR1) in rats with normal renal function and in vitro in bone-derived osteoblast-like cells. We studied the regulation of FGF23 by FGFR1 in vivo in acute and chronic uremia in mice and rats. Folic acid-induced acute kidney injury increased calvaria FGF23 mRNA and serum FGF23 and parathyroid hormone (PTH) levels at 6 h. The FGFR1 receptor inhibitor PD173074 prevented the folic acid-induced increase in both FGF23 mRNA and serum levels but had no effect on serum PTH levels. A more prolonged uremia due to an adenine high-phosphorus diet for 14 days resulted in high levels of FGF23 mRNA and serum FGF23 and PTH. PD173074 decreased serum FGF23 and mRNA levels with no effect on PTH in the adenine high phosphorus-induced uremic rats. Therefore, a derangement in FGF23 regulation starts early in the course of acute kidney injury, is in part independent of the increase in serum PTH, and involves activation of FGFR1. It is possible that FGFR1 in the osteocyte is activated by locally produced canonical FGFs, which are increased in uremia. This is the first demonstration that activation of FGFR1 is essential for the high levels of FGF23 in acute and chronic experimental uremia.
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Affiliation(s)
- Alia Hassan
- Minerva Center for Calcium and Bone Metabolism, Nephrology Services, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Karina Durlacher
- Minerva Center for Calcium and Bone Metabolism, Nephrology Services, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Justin Silver
- Minerva Center for Calcium and Bone Metabolism, Nephrology Services, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Tally Naveh-Many
- Minerva Center for Calcium and Bone Metabolism, Nephrology Services, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Ronen Levi
- Minerva Center for Calcium and Bone Metabolism, Nephrology Services, Hadassah Hebrew University Medical Center, Jerusalem, Israel
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