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Xiang Z, Wang M, Miao C, Jin D, Wang H. Mechanism of calcitriol regulating parathyroid cells in secondary hyperparathyroidism. Front Pharmacol 2022; 13:1020858. [PMID: 36267284 PMCID: PMC9577402 DOI: 10.3389/fphar.2022.1020858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 09/15/2022] [Indexed: 12/03/2022] Open
Abstract
A common consequence of chronic renal disease is secondary hyperparathyroidism (SHPT) and is closely related to the mortality and morbidity of uremia patients. Secondary hyperparathyroidism (SHPT) is caused by excessive PTH production and release, as well as parathyroid enlargement. At present, the mechanism of cell proliferation in secondary hyperparathyroidism (SHPT) is not completely clear. Decreased expression of the vitamin D receptor (VDR) and calcium-sensing receptor (CaSR), and 1,25(OH)2D3 insufficiency all lead to a decrease in cell proliferation suppression, and activation of multiple pathways is also involved in cell proliferation in renal hyperparathyroidism. The interaction between the parathormone (PTH) and parathyroid hyperplasia and 1,25(OH)2D3 has received considerable attention. 1,25(OH)2D3 is commonly applied in the therapy of renal hyperparathyroidism. It regulates the production of parathormone (PTH) and parathyroid cell proliferation through transcription and post-transcription mechanisms. This article reviews the role of 1,25(OH)2D3 in parathyroid cells in secondary hyperparathyroidism and its current understanding and potential molecular mechanism.
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The Influence of the Severity of Early Chronic Kidney Disease on Oxidative Stress in Patients with and without Type 2 Diabetes Mellitus. Int J Mol Sci 2022; 23:ijms231911196. [PMID: 36232497 PMCID: PMC9569590 DOI: 10.3390/ijms231911196] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 09/14/2022] [Accepted: 09/15/2022] [Indexed: 11/17/2022] Open
Abstract
Early Chronic Kidney Disease (CKD) is a condition that tends to progress to End-Stage Kidney Disease (ESKD). Early diagnosis of kidney disease in the early stages can reduce complications. Alterations in renal function represent a complication of diabetes mellitus (DM). The mechanisms underlying the progression of CKD in diabetes could be associated with oxidative and inflammatory processes. This study aimed to evaluate the state of inflammation and oxidative stress (OS) on the progression of CKD in the early stages in patients with and without type 2 diabetes mellitus (T2DM). An analytical cross-sectional study was carried out in patients with CKD in early stages (1, 2, 3) with and without T2DM. The ELISA method determined the expression of pro-inflammatory cytokines IL-6 and TNF-α as well as lipoperoxides (LPO), nitric oxide (NO), and superoxide dismutase activity (SOD). Colorimetric methods determined glutathione peroxidase (GPx) and total antioxidant capacity (TAC). Patients with CKD and T2DM had significantly decreased antioxidant defenses for SOD (p < 0.01), GPx (p < 0.01), and TAC (p < 0.01) compared to patients without T2DM. Consequently, patients with T2DM had higher concentrations of oxidant markers, NO (p < 0.01), inflammation markers, IL-6 (p < 0.01), and TNF-α than patients without T2DM. CKD stages were not related to oxidative, antioxidant, and inflammatory marker outcomes in T2DM patients. Patients without T2DM presented an increase in SOD (p = 0.04) and a decrease in NO (p < 0.01) when the stage of CKD increased. In conclusion, patients with T2DM present higher levels of oxidative and inflammatory markers accompanied by a decrease in antioxidant defense. However, these oxidative status markers were associated with CKD stage progression in patients without T2DM. Thus, NO and SOD markers could help detect the early stages of CKD in patients who have not yet developed metabolic comorbidities such as T2DM.
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Meshkini F, Soltani S, Clark CCT, Tam V, Meyre D, Toupchian O, Saraf-Bank S, Abdollahi S. The effect of vitamin D supplementation on serum levels of fibroblast growth factor- 23: A systematic review and meta-analysis of randomized controlled trials. J Steroid Biochem Mol Biol 2022; 215:106012. [PMID: 34710560 DOI: 10.1016/j.jsbmb.2021.106012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 09/18/2021] [Accepted: 10/21/2021] [Indexed: 12/29/2022]
Abstract
Previous studies of the effect of vtamin D on serum levels of fibroblast growth factor- 23 (FGF-23) have yeilded an inconsistent findings. This systematic review and meta-analysis of randomized controlled trials (RCTs) sought to investigate the effect of vitamin D supplementation on serum levels of FGF-23. PubMed, Scopus, ISI Web of Science, and the Cochrane Library were searched, from database inception to November 2020, for RCTs that evaluated the effects of native or active vitamin D supplementation on serum levels of FGF-23 in adults. Weighted mean difference (WMD) were calculated and random effects meta-analysis was used to estimate the overall effects. Twenty-seven trials were included in the meta-analysis. Supplementation with native vitamin D (23 studies, n = 2247 participants; weighted mean difference [WMD] = 0.5 pg/mL, 95 % CI: -0.52 to 1.51, P = 0.33; I2 = 29.9 %), and active vitamin D (5 studies, n = 342 participants, WMD = 29.45 pg/mL, 95 % CI: -3.9 to 62.81, P = 0.08; I2 = 99.3%) had no significant effects on serum FGF-23 concentration. In subgroup analyses, supplementation with ergocalciferol (3 studies, n = 205 participants; WMD = 18.27 pg/mL, 95 % CI: 5.36-31.17, P = 0.006), and daily dosing regimens (9 studies, n = 1374 participants; WMD = 0.41 pg/mL, 95 % CI: 0.22 to 0.59, P < 0.001) increased serum FGF-23 levels compared to control. Overall, our findings revealed no significan effect of vitamin D supplementation on serum FGF-23 concentration. However, further high quality, large-scale studies are needed to better elucidate this relationship.
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Affiliation(s)
- Fatemeh Meshkini
- Department of Biochemistry, School of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran; Student Research Committee, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Sepideh Soltani
- Yazd Cardiovascular Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Cain C T Clark
- Centre for Intelligent Healthcare, Coventry University, Coventry, CV1 5FB, UK
| | - Vivian Tam
- Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, Canada
| | - David Meyre
- Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, Canada; Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Canada
| | - Omid Toupchian
- Department of Nutrition, School of Public Health, North Khorasan University of Medical Sciences, Bojnurd, Iran
| | - Sahar Saraf-Bank
- Food Security Research Center, Department of Community Nutrition, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Shima Abdollahi
- Department of Nutrition, School of Public Health, North Khorasan University of Medical Sciences, Bojnurd, Iran.
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Franco ML, Beyerstedt S, Rangel ÉB. Klotho and Mesenchymal Stem Cells: A Review on Cell and Gene Therapy for Chronic Kidney Disease and Acute Kidney Disease. Pharmaceutics 2021; 14:pharmaceutics14010011. [PMID: 35056905 PMCID: PMC8778857 DOI: 10.3390/pharmaceutics14010011] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 12/16/2021] [Accepted: 12/17/2021] [Indexed: 02/07/2023] Open
Abstract
Chronic kidney disease (CKD) and acute kidney injury (AKI) are public health problems, and their prevalence rates have increased with the aging of the population. They are associated with the presence of comorbidities, in particular diabetes mellitus and hypertension, resulting in a high financial burden for the health system. Studies have indicated Klotho as a promising therapeutic approach for these conditions. Klotho reduces inflammation, oxidative stress and fibrosis and counter-regulates the renin-angiotensin-aldosterone system. In CKD and AKI, Klotho expression is downregulated from early stages and correlates with disease progression. Therefore, the restoration of its levels, through exogenous or endogenous pathways, has renoprotective effects. An important strategy for administering Klotho is through mesenchymal stem cells (MSCs). In summary, this review comprises in vitro and in vivo studies on the therapeutic potential of Klotho for the treatment of CKD and AKI through the administration of MSCs.
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Affiliation(s)
- Marcella Liciani Franco
- Albert Einstein Research and Education Institute, Hospital Israelita Albert Einstein, Sao Paulo 05652-900, Brazil; (M.L.F.); (S.B.)
| | - Stephany Beyerstedt
- Albert Einstein Research and Education Institute, Hospital Israelita Albert Einstein, Sao Paulo 05652-900, Brazil; (M.L.F.); (S.B.)
| | - Érika Bevilaqua Rangel
- Albert Einstein Research and Education Institute, Hospital Israelita Albert Einstein, Sao Paulo 05652-900, Brazil; (M.L.F.); (S.B.)
- Nephrology Division, Federal University of São Paulo, Sao Paulo 04038-901, Brazil
- Correspondence: ; Tel.: +55-11-2151-2148
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Mace ML, Gravesen E, Nordholm A, Egstrand S, Morevati M, Nielsen C, Kjaer A, Behets G, D'Haese P, Olgaard K, Lewin E. Chronic Kidney Disease-Induced Vascular Calcification Impairs Bone Metabolism. J Bone Miner Res 2021; 36:510-522. [PMID: 33301619 PMCID: PMC7988613 DOI: 10.1002/jbmr.4203] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 10/21/2020] [Accepted: 10/23/2020] [Indexed: 12/31/2022]
Abstract
An association between lower bone mineral density (BMD) and presence of vascular calcification (VC) has been reported in several studies. Chronic kidney disease (CKD) causes detrimental disturbances in the mineral balance, bone turnover, and development of severe VC. Our group has previously demonstrated expression of Wnt inhibitors in calcified arteries of CKD rats. Therefore, we hypothesized that the CKD-induced VC via this pathway signals to bone and induces bone loss. To address this novel hypothesis, we developed a new animal model using isogenic aorta transplantation (ATx). Severely calcified aortas from uremic rats were transplanted into healthy rats (uremic ATx). Transplantation of normal aortas into healthy rats (normal ATx) and age-matched rats (control) served as control groups. Trabecular tissue mineral density, as measured by μCT, was significantly lower in uremic ATx rats compared with both control groups. Uremic ATx rats showed a significant upregulation of the mineralization inhibitors osteopontin and progressive ankylosis protein homolog in bone. In addition, we found significant changes in bone mRNA levels of several genes related to extracellular matrix, bone turnover, and Wnt signaling in uremic ATx rats, with no difference between normal ATx and control. The bone histomorphometry analysis showed significant lower osteoid area in uremic ATx compared with normal ATx along with a trend toward fewer osteoblasts as well as more osteoclasts in the erosion lacunae. Uremic ATx and normal ATx had similar trabecular number and thickness. The bone formation rate did not differ between the three groups. Plasma biochemistry, including sclerostin, kidney, and mineral parameters, were similar between all three groups. ex vivo cultures of aorta from uremic rats showed high secretion of the Wnt inhibitor sclerostin. In conclusion, the presence of VC lowers BMD, impairs bone metabolism, and affects several pathways in bone. The present results prove the existence of a vasculature to bone tissue cross-talk. © 2020 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Maria L Mace
- Department of Nephrology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Eva Gravesen
- Department of Nephrology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Anders Nordholm
- Department of Nephrology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.,Department of Nephrology, Herlev Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Soeren Egstrand
- Department of Nephrology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.,Department of Nephrology, Herlev Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Marya Morevati
- Department of Nephrology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Carsten Nielsen
- Department of Clinical Physiology, Nuclear Medicine and PET and Cluster for Molecular Imaging, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Andreas Kjaer
- Department of Clinical Physiology, Nuclear Medicine and PET and Cluster for Molecular Imaging, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Geert Behets
- Department of Biomedical Sciences, Laboratory of Pathophysiology, University of Antwerp, Antwerp, Belgium
| | - Patrick D'Haese
- Department of Biomedical Sciences, Laboratory of Pathophysiology, University of Antwerp, Antwerp, Belgium
| | - Klaus Olgaard
- Department of Nephrology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Ewa Lewin
- Department of Nephrology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.,Department of Nephrology, Herlev Hospital, University of Copenhagen, Copenhagen, Denmark
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Mace ML, Olgaard K, Lewin E. New Aspects of the Kidney in the Regulation of Fibroblast Growth Factor 23 (FGF23) and Mineral Homeostasis. Int J Mol Sci 2020; 21:E8810. [PMID: 33233840 PMCID: PMC7699902 DOI: 10.3390/ijms21228810] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 11/16/2020] [Accepted: 11/19/2020] [Indexed: 02/07/2023] Open
Abstract
The bone-derived hormone fibroblast growth factor 23 (FGF23) acts in concert with parathyroid hormone (PTH) and the active vitamin D metabolite calcitriol in the regulation of calcium (Ca) and phosphate (P) homeostasis. More factors are being identified to regulate FGF23 levels and the endocrine loops between the three hormones. The present review summarizes the complex regulation of FGF23 and the disturbed FGF23/Klotho system in chronic kidney disease (CKD). In addition to the reduced ability of the injured kidney to regulate plasma levels of FGF23, several CKD-related factors have been shown to stimulate FGF23 production. The high circulating FGF23 levels have detrimental effects on erythropoiesis, the cardio-vascular system and the immune system, all contributing to the disturbed system biology in CKD. Moreover, new factors secreted by the injured kidney and the uremic calcified vasculature play a role in the mineral and bone disorder in CKD and create a vicious pathological crosstalk.
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Affiliation(s)
- Maria L. Mace
- Department of Nephrology, Rigshospitalet, University of Copenhagen, 2100 Copenhagen, Denmark; (K.O.); (E.L.)
| | - Klaus Olgaard
- Department of Nephrology, Rigshospitalet, University of Copenhagen, 2100 Copenhagen, Denmark; (K.O.); (E.L.)
| | - Ewa Lewin
- Department of Nephrology, Rigshospitalet, University of Copenhagen, 2100 Copenhagen, Denmark; (K.O.); (E.L.)
- Department of Nephrology, Herlev Hospital, University of Copenhagen, 2730 Herlev, Denmark
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Kolodziejski PA, Sassek M, Bien J, Leciejewska N, Szczepankiewicz D, Szczepaniak B, Wojciechowska M, Nogowski L, Nowak KW, Strowski MZ, Pruszynska-Oszmalek E. FGF-1 modulates pancreatic β-cell functions/metabolism: An in vitro study. Gen Comp Endocrinol 2020; 294:113498. [PMID: 32360543 DOI: 10.1016/j.ygcen.2020.113498] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Revised: 04/26/2020] [Accepted: 04/27/2020] [Indexed: 12/15/2022]
Abstract
Fibroblast growth factor 1 (FGF-1), also known as acidic fibroblast growth factor (aFGF), is a growth factor and signaling protein encoded by the Fgf1 gene. Previous studies have shown that FGF-1 may also participate in the regulation of glucose metabolism, both in healthy organisms and in pathological conditions such as diabetes. Because insulin the main regulator of glucose metabolism is secreted from pancreatic beta cells, we investigated whether FGF-1 directly affects the secretion of this hormone and regulates the metabolism of beta cells and isolated pancreatic islets. By using insulin-producing INS-1E cells and isolated pancreatic islets, we investigated the effect of FGF-1 on cell proliferation, viability, apoptosis, and insulin expression and secretion. Our study showed that FGF1 and fibroblast growth factor receptors (FgfRs: FgfR1, FgfR2, FgfR3, and FgfR4) are present on mRNA level in INS-1E cells and isolated rat pancreatic islets. We also proved that FGF1 stimulates the proliferation of INS-1E beta cells and enhances the viability of these cells and that of isolated pancreatic islet cells, and that ERK1/2 kinase is involved in the regulation of INS-1E cell proliferation. Moreover, we found that FGF1 can stimulate insulin secretion from both INS-1E cells and isolated rat pancreatic islets. Thus, the FGF1 peptide increases cell survival and decreases cell death. The obtained results indicate that FGF1 may play a role in controlling the physiology and metabolism of pancreatic beta cells as well as glycemia.
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Affiliation(s)
- Pawel A Kolodziejski
- Department of Animal Physiology, Biochemistry and Biostructure, Poznan University of Life Sciences, Wolynska Street 35, 60-637 Poznan, Poland
| | - Maciej Sassek
- Department of Animal Physiology, Biochemistry and Biostructure, Poznan University of Life Sciences, Wolynska Street 35, 60-637 Poznan, Poland.
| | - Jakub Bien
- Department of Animal Physiology, Biochemistry and Biostructure, Poznan University of Life Sciences, Wolynska Street 35, 60-637 Poznan, Poland
| | - Natalia Leciejewska
- Department of Animal Physiology, Biochemistry and Biostructure, Poznan University of Life Sciences, Wolynska Street 35, 60-637 Poznan, Poland
| | - Dawid Szczepankiewicz
- Department of Animal Physiology, Biochemistry and Biostructure, Poznan University of Life Sciences, Wolynska Street 35, 60-637 Poznan, Poland
| | - Beata Szczepaniak
- Department of Animal Physiology, Biochemistry and Biostructure, Poznan University of Life Sciences, Wolynska Street 35, 60-637 Poznan, Poland
| | | | - Leszek Nogowski
- Department of Animal Physiology, Biochemistry and Biostructure, Poznan University of Life Sciences, Wolynska Street 35, 60-637 Poznan, Poland
| | - Krzysztof W Nowak
- Department of Animal Physiology, Biochemistry and Biostructure, Poznan University of Life Sciences, Wolynska Street 35, 60-637 Poznan, Poland
| | - Mathias Z Strowski
- Department of Hepatology and Gastroenterology, Charité - University Medicine Berlin, 13353 Berlin, Germany; Department of Internal Medicine - Gastroenterology, Park-Klinik Weissensee, 13086 Berlin, Germany
| | - Ewa Pruszynska-Oszmalek
- Department of Animal Physiology, Biochemistry and Biostructure, Poznan University of Life Sciences, Wolynska Street 35, 60-637 Poznan, Poland
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Egstrand S, Nordholm A, Morevati M, Mace ML, Hassan A, Naveh-Many T, Rukov JL, Gravesen E, Olgaard K, Lewin E. A molecular circadian clock operates in the parathyroid gland and is disturbed in chronic kidney disease associated bone and mineral disorder. Kidney Int 2020; 98:1461-1475. [PMID: 32721445 DOI: 10.1016/j.kint.2020.06.034] [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: 01/05/2020] [Revised: 06/17/2020] [Accepted: 06/18/2020] [Indexed: 01/16/2023]
Abstract
Circadian rhythms in metabolism, hormone secretion, cell cycle and locomotor activity are regulated by a molecular circadian clock with the master clock in the suprachiasmatic nucleus of the central nervous system. However, an internal clock is also expressed in several peripheral tissues. Although about 10% of all genes are regulated by clock machinery an internal molecular circadian clock in the parathyroid glands has not previously been investigated. Parathyroid hormone secretion exhibits a diurnal variation and parathyroid hormone gene promoter contains an E-box like element, a known target of circadian clock proteins. Therefore, we examined whether an internal molecular circadian clock is operating in parathyroid glands, whether it is entrained by feeding and how it responds to chronic kidney disease. As uremia is associated with extreme parathyroid growth and since disturbed circadian rhythm is related to abnormal growth, we examined the expression of parathyroid clock and clock-regulated cell cycle genes in parathyroid glands of normal and uremic rats. Circadian clock genes were found to be rhythmically expressed in normal parathyroid glands and this clock was minimally entrained by feeding. Diurnal regulation of parathyroid glands was next examined. Significant rhythmicity of fibroblast-growth-factor-receptor-1, MafB and Gata3 was found. In uremic rats, deregulation of circadian clock genes and the cell cycle regulators, Cyclin D1, c-Myc, Wee1 and p27, which are influenced by the circadian clock, was found in parathyroid glands as well as the aorta. Thus, a circadian clock operates in parathyroid glands and this clock and downstream cell cycle regulators are disturbed in uremia and may contribute to dysregulated parathyroid proliferation in secondary hyperparathyroidism.
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Affiliation(s)
- Søren Egstrand
- Nephrological Department, Herlev Hospital, University of Copenhagen, Copenhagen, Denmark; Nephrological Department, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Anders Nordholm
- Nephrological Department, Herlev Hospital, University of Copenhagen, Copenhagen, Denmark; Nephrological Department, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Marya Morevati
- Nephrological Department, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Maria L Mace
- Nephrological Department, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Alia Hassan
- 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
| | - Jakob L Rukov
- Nephrological Department, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Eva Gravesen
- Nephrological Department, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Klaus Olgaard
- Nephrological Department, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Ewa Lewin
- Nephrological Department, Herlev Hospital, University of Copenhagen, Copenhagen, Denmark; Nephrological Department, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
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Uchiyama T, Ohkido I, Nakashima A, Saito Y, Okabe M, Yokoo T. Severe chronic kidney disease environment reduced calcium-sensing receptor expression in parathyroid glands of adenine-induced rats even without high phosphorus diet. BMC Nephrol 2020; 21:219. [PMID: 32517664 PMCID: PMC7285719 DOI: 10.1186/s12882-020-01880-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 06/02/2020] [Indexed: 02/08/2023] Open
Abstract
Background Chronic kidney disease (CKD) disrupts mineral homeostasis and its main underlying cause is secondary hyperparathyroidism (SHPT). We previously reported that calcium-sensing receptor (CaSR) mRNA and protein expression in parathyroid glands (PTGs) significantly decreased in a CKD rat model induced by a 5/6 nephrectomy that were fed a high phosphorus diet. However, there was a significant difference in the severity of CKD between high phosphorus and adequate phosphorus diet groups. Thus, it was unclear whether CKD environment or the high phosphorus diet influenced CaSR expression, and the underlying mechanism remains largely unknown. Methods CKD was induced in rats with 0.75% adenine-containing diet. CKD and control rats were maintained for 5 days and 2 weeks on diets with 0.7% or 1.3% phosphorus. For gene expression analysis, quantitative real-time polymerase chain reaction was performed with TaqMan probes. Protein expression was analyzed by immunohistochemistry. Results PTG CaSR expression significantly decreased in the presence of a severe CKD environment, even without the high phosphate load. Ki67 expressing cells in PTGs were significantly higher only in the CKD rats fed a high phosphorus diet. Furthermore, among the many genes that could affect CaSR expression, only vitamin D receptor (VDR) and glial cells missing 2 (Gcm2) showed significant changes. Moreover, Gcm2 was significantly reduced at an early stage without significant changes in serum calcium, phosphorus and 1,25(OH)2 vitamin D, and there was no significant reduction in CaSR and VDR expressions. Then, significantly elevated Ki67-positive cell numbers were also only observed in the early CKD PTGs with high-phosphorus diets. Conclusions Our data suggest that the cause of the decreased PTG CaSR expression is the reduction in VDR and Gcm2 expression; Gcm2 may play a role in the onset and progression of SHPT.
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Affiliation(s)
- Taketo Uchiyama
- Division of Nephrology and Hypertension, Department of Internal Medicine, the Jikei University School of Medicine, Tokyo, Japan
| | - Ichiro Ohkido
- Division of Nephrology and Hypertension, Department of Internal Medicine, the Jikei University School of Medicine, Tokyo, Japan.
| | - Akio Nakashima
- Division of Nephrology and Hypertension, Department of Internal Medicine, the Jikei University School of Medicine, Tokyo, Japan
| | - Yatsumu Saito
- Division of Nephrology and Hypertension, Department of Internal Medicine, the Jikei University School of Medicine, Tokyo, Japan
| | - Masataka Okabe
- Department of Anatomy, the Jikei University School of Medicine, Tokyo, Japan
| | - Takashi Yokoo
- Division of Nephrology and Hypertension, Department of Internal Medicine, the Jikei University School of Medicine, Tokyo, Japan
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Neuburg S, Dussold C, Gerber C, Wang X, Francis C, Qi L, David V, Wolf M, Martin A. Genetic background influences cardiac phenotype in murine chronic kidney disease. Nephrol Dial Transplant 2019; 33:1129-1137. [PMID: 29309658 DOI: 10.1093/ndt/gfx332] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 11/03/2017] [Indexed: 01/01/2023] Open
Abstract
Background Levels of fibroblast growth factor 23 (FGF23) increase early in chronic kidney disease (CKD) and are independently associated with left ventricular hypertrophy (LVH), heart failure and death. Experimental models of CKD with elevated FGF23 and LVH are needed. We hypothesized that slow rates of CKD progression in the Col4a3 knockout (Col4a3KO) mouse model of CKD would promote development of LVH by prolonging exposure to elevated FGF23. Methods We studied congenic Col4a3KO and wild-type (WT) mice with either 75% 129X1/SvJ (129Sv) or 94% C57Bl6/J (B6) genomes. Results B6-Col4a3KO lived longer than 129Sv-Col4a3KO mice (21.4 ± 0.6 versus 11.4 ± 0.4 weeks; P < 0.05). 10-week-old 129Sv-Col4a3KO mice showed impaired renal function (blood urea nitrogen 191 ± 39 versus 34 ± 4 mg/dL), hyperphosphatemia (14.1 ± 1.4 versus 6.8 ± 0.3 mg/dL) and 33-fold higher serum FGF23 levels (P < 0.05 versus WT for each). Consistent with their slower CKD progression, 10 week-old B6-Col4a3KO mice showed milder impairment of renal function than 129Sv-Col4a3KO mice and modest FGF23 elevation without other alterations of mineral metabolism. At 20 weeks, further declines in renal function in B6-Col4a3KO mice was accompanied by hyperphosphatemia and 8-fold higher FGF23 levels (P < 0.05 versus WT for each). Only the 20-week-old B6-Col4a3KO mice developed LVH (LV mass 125 ± 3 versus 98 ± 6 mg; P < 0.05 versus WT) in association with significantly increased cardiac expression of FGF receptor 4 (FGFR4) messenger RNA and protein and markers of LVH (Atrial natriuretic peptide (ANP), B-type natriuretic peptide (BNP), beta-myosin heavy chain (β-MHC); P < 0.05 versus WT for each). Conclusions In conclusion, B6-Col4a3KO mice manifest slower CKD progression and longer survival than 129Sv-Col4a3KO mice and can serve as a novel model of cardiorenal disease.
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Affiliation(s)
- Samantha Neuburg
- Division of Nephrology and Hypertension, Department of Medicine, Center for Translational Metabolism and Health, Institute for Public Health and Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Corey Dussold
- Division of Nephrology and Hypertension, Department of Medicine, Center for Translational Metabolism and Health, Institute for Public Health and Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Claire Gerber
- Division of Nephrology and Hypertension, Department of Medicine, Center for Translational Metabolism and Health, Institute for Public Health and Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Xueyan Wang
- Division of Nephrology and Hypertension, Department of Medicine, Center for Translational Metabolism and Health, Institute for Public Health and Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Connor Francis
- Division of Nephrology and Hypertension, Department of Medicine, Center for Translational Metabolism and Health, Institute for Public Health and Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Lixin Qi
- Division of Nephrology and Hypertension, Department of Medicine, Center for Translational Metabolism and Health, Institute for Public Health and Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Valentin David
- Division of Nephrology and Hypertension, Department of Medicine, Center for Translational Metabolism and Health, Institute for Public Health and Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Myles Wolf
- Division of Nephrology, Department of Medicine, Duke Clinical Research Institute, Duke University, Durham, NC, USA
| | - Aline Martin
- Division of Nephrology and Hypertension, Department of Medicine, Center for Translational Metabolism and Health, Institute for Public Health and Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
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11
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Nordholm A, Mace ML, Gravesen E, Hofman-Bang J, Morevati M, Olgaard K, Lewin E. Klotho and activin A in kidney injury: plasma Klotho is maintained in unilateral obstruction despite no upregulation of Klotho biosynthesis in the contralateral kidney. Am J Physiol Renal Physiol 2018; 314:F753-F762. [PMID: 29187373 PMCID: PMC6031917 DOI: 10.1152/ajprenal.00528.2017] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 11/22/2017] [Accepted: 11/27/2017] [Indexed: 12/17/2022] Open
Abstract
In a new paradigm of etiology related to chronic kidney disease-mineral and bone disorder (CKD-MBD), kidney injury may cause induction of factors in the injured kidney that are released into the circulation and thereby initiate and maintain renal fibrosis and CKD-MBD. Klotho is believed to ameliorate renal fibrosis and CKD-MBD, while activin A might have detrimental effects. The unilateral ureter obstruction (UUO) model is used here to examine this concept by investigating early changes related to renal fibrosis in the obstructed kidney, untouched contralateral kidney, and vasculature which might be affected by secreted factors from the obstructed kidney, and comparing with unilateral nephrectomized controls (UNX). Obstructed kidneys showed early Klotho gene and protein depletion, whereas plasma Klotho increased in both UUO and UNX rats, indicating an altered metabolism of Klotho. Contralateral kidneys had no compensatory upregulation of Klotho and maintained normal expression of the examined fibrosis-related genes, as did remnant UNX kidneys. UUO caused upregulation of transforming growth factor-β and induction of periostin and activin A in obstructed kidneys without changes in the contralateral kidneys. Plasma activin A doubled in UUO rats after 10 days while no changes were seen in UNX rats, suggesting secretion of activin A from the obstructed kidney with potentially systemic effects on CKD-MBD. As such, increased aortic sclerostin was observed in UUO rats compared with UNX and normal controls. The present results are in line with the new paradigm and show very early vascular effects of unilateral kidney fibrosis, supporting the existence of a new kidney-vasculature axis.
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Affiliation(s)
- Anders Nordholm
- Nephrological Department B, Herlev Hospital, Herlev, University of Copenhagen , Copenhagen , Denmark
| | - Maria L Mace
- Nephrological Department B, Herlev Hospital, Herlev, University of Copenhagen , Copenhagen , Denmark
- Nephrological Department P, Rigshospitalet, Copenhagen , Denmark
| | - Eva Gravesen
- Nephrological Department P, Rigshospitalet, Copenhagen , Denmark
| | | | - Marya Morevati
- Nephrological Department P, Rigshospitalet, Copenhagen , Denmark
| | - Klaus Olgaard
- Nephrological Department P, Rigshospitalet, Copenhagen , Denmark
| | - Ewa Lewin
- Nephrological Department B, Herlev Hospital, Herlev, University of Copenhagen , Copenhagen , Denmark
- Nephrological Department P, Rigshospitalet, Copenhagen , Denmark
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12
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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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13
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Baldan A, Giusti A, Bosi C, Malaventura C, Forni G, Borgna-Pignatti C. Pseudoxanthoma Elasticum-Like in β-Thalassemia Major, a matter of α-Klotho and Parathyroid Hormone? Hemoglobin 2017; 41:254-259. [DOI: 10.1080/03630269.2017.1403927] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Alessandro Baldan
- Department of Medical Sciences, Section of Pediatrics, University of Ferrara, Ferrara, Italy
| | - Andrea Giusti
- Bone Clinic, Department of Geriatric Care, Orthogeriatrics and Rehabilitation, Galliera Hospital, Genoa, Italy
| | - Cristina Bosi
- Department of Medical Sciences, Section of Internal and Cardio-Respiratory Medicine, University of Ferrara, Ferrara, Italy
| | - Cristina Malaventura
- Department of Medical Sciences, Section of Pediatrics, University of Ferrara, Ferrara, Italy
| | - Gianluca Forni
- Center of Microcitemia and Congenital Anemias, Galliera Hospital, Genoa, Italy
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14
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Kidney fibroblast growth factor 23 does not contribute to elevation of its circulating levels in uremia. Kidney Int 2017; 92:165-178. [PMID: 28341272 DOI: 10.1016/j.kint.2017.01.015] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 12/21/2016] [Accepted: 01/05/2017] [Indexed: 02/08/2023]
Abstract
Fibroblast growth factor 23 (FGF23) secreted by osteocytes is a circulating factor essential for phosphate homeostasis. High plasma FGF23 levels are associated with cardiovascular complications and mortality. Increases of plasma FGF23 in uremia antedate high levels of phosphate, suggesting a disrupted feedback regulatory loop or an extra-skeletal source of this phosphatonin. Since induction of FGF23 expression in injured organs has been reported we decided to examine the regulation of FGF23 gene and protein expressions in the kidney and whether kidney-derived FGF23 contributes to the high plasma levels of FGF23 in uremia. FGF23 mRNA was not detected in normal kidneys, but was clearly demonstrated in injured kidneys, already after four hours in obstructive nephropathy and at 8 weeks in the remnant kidney of 5/6 nephrectomized rats. No renal extraction was found in uremic rats in contrast to normal rats. Removal of the remnant kidney had no effect on plasma FGF23 levels. Well-known regulators of FGF23 expression in bone, such as parathyroid hormone, calcitriol, and inhibition of the FGF receptor by PD173074, had no impact on kidney expression of FGF23. Thus, the only direct contribution of the injured kidney to circulating FGF23 levels in uremia appears to be reduced renal extraction of bone-derived FGF23. Kidney-derived FGF23 does not generate high plasma FGF23 levels in uremia and is regulated differently than the corresponding regulation of FGF23 gene expression in bone.
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15
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Sharaf El Din UAA, Salem MM, Abdulazim DO. Vascular calcification: When should we interfere in chronic kidney disease patients and how? World J Nephrol 2016; 5:398-417. [PMID: 27648404 PMCID: PMC5011247 DOI: 10.5527/wjn.v5.i5.398] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 04/20/2016] [Accepted: 06/27/2016] [Indexed: 02/06/2023] Open
Abstract
Chronic kidney disease (CKD) patients are endangered with the highest mortality rate compared to other chronic diseases. Cardiovascular events account for up to 60% of the fatalities. Cardiovascular calcifications affect most of the CKD patients. Most of this calcification is related to disturbed renal phosphate handling. Fibroblast growth factor 23 and klotho deficiency were incriminated in the pathogenesis of vascular calcification through different mechanisms including their effects on endothelium and arterial wall smooth muscle cells. In addition, deficient klotho gene expression, a constant feature of CKD, promotes vascular pathology and shares in progression of the CKD. The role of gut in the etio-pathogenesis of systemic inflammation and vascular calcification is a newly discovered mechanism. This review will cover the medical history, prevalence, pathogenesis, clinical relevance, different tools used to diagnose, the ideal timing to prevent or to withhold the progression of vascular calcification and the different medications and medical procedures that can help to prolong the survival of CKD patients.
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16
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Uchiyama T, Tatsumi N, Kamejima S, Waku T, Ohkido I, Yokoyama K, Yokoo T, Okabe M. Hypermethylation of the CaSR and VDR genes in the parathyroid glands in chronic kidney disease rats with high-phosphate diet. Hum Cell 2016; 29:155-61. [PMID: 27589858 DOI: 10.1007/s13577-016-0143-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 07/27/2016] [Indexed: 01/04/2023]
Abstract
Chronic kidney disease (CKD) disrupts mineral homeostasis and its representative pathosis is defined as secondary hyperparathyroidism (SHPT). SHPT occurs during the early course of progressive renal insufficiency, and is associated with mortality and cardiovascular events. SHPT results in reduction of calcium-sensing receptor (CaSR) and vitamin D receptor (VDR) in the parathyroid glands during CKD. However, the precise mechanism of CaSR and VDR reduction is largely unknown. CKD was induced through two-step 5/6 nephrectomy, and then CKD rats and sham-operated rats were maintained for 8 weeks on diets containing 0.7 % phosphorus (normal phosphate) or 1.2 % phosphorus (high phosphate). In gene expression analysis, TaqMan probes were used for quantitative real-time polymerase chain reaction. Finally, CaSR and VDR protein expressions were analyzed using immunohistochemistry. DNA methylation analysis was performed using a restriction digestion and quantitative PCR. CaSR and VDR mRNA were reduced only in CKD rats fed the high-phosphorus diets (CKD HP), then CaSR and VDR immunohistochemical expressions were compatible with gene expression assay. SHPT was then confirmed only in CKD HP rats. Furthermore, sole CKD HP rats showed the hypermethylation in CaSR and VDR genes; however, the percentage methylation of both genes was low. Although CaSR and VDR hypermethylation was demonstrated in PTGs of CKD HP rats, the extent of hypermethylation was insufficient to support the relevance between hypermethylation and down-regulation of gene expression because of the low percentage of methylation. Consequently, our data suggest that mechanisms, other than DNA hypermethylation, were responsible for the reduction in mRNA and protein levels of CaSR and VDR in PTGs of CKD HP rats.
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Affiliation(s)
- Taketo Uchiyama
- Department of Anatomy, The Jikei University School of Medicine, Tokyo, Japan.,Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
| | - Norifumi Tatsumi
- Department of Anatomy, The Jikei University School of Medicine, Tokyo, Japan
| | - Sahoko Kamejima
- Department of Anatomy, The Jikei University School of Medicine, Tokyo, Japan.,Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
| | - Tsuyoshi Waku
- Laboratory for Genetic Code, Graduate School of Life and Medical Sciences, Doshisha University, Kyotanabe, Japan
| | - Ichiro Ohkido
- Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
| | - Keitaro Yokoyama
- Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
| | - Takashi Yokoo
- Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
| | - Masataka Okabe
- Department of Anatomy, The Jikei University School of Medicine, Tokyo, Japan.
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17
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Sharaf El Din UAA, Salem MM, Abdulazim DO. Stop chronic kidney disease progression: Time is approaching. World J Nephrol 2016; 5:258-273. [PMID: 27152262 PMCID: PMC4848149 DOI: 10.5527/wjn.v5.i3.258] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2015] [Revised: 01/26/2016] [Accepted: 02/24/2016] [Indexed: 02/06/2023] Open
Abstract
Progression of chronic kidney disease (CKD) is inevitable. However, the last decade has witnessed tremendous achievements in this field. Today we are optimistic; the dream of withholding this progression is about to be realistic. The recent discoveries in the field of CKD management involved most of the individual diseases leading the patients to end-stage renal disease. Most of these advances involved patients suffering diabetic kidney disease, chronic glomerulonephritis, polycystic kidney disease, renal amyloidosis and chronic tubulointerstitial disease. The chronic systemic inflammatory status and increased oxidative stress were also investigated. This inflammatory status influences the anti-senescence Klotho gene expression. The role of Klotho in CKD progression together with its therapeutic value are explored. The role of gut as a major source of inflammation, the pathogenesis of intestinal mucosal barrier damage, the role of intestinal alkaline phosphatase and the dietary and therapeutic implications add a novel therapeutic tool to delay CKD progression.
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18
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Rukov JL, Gravesen E, Mace ML, Hofman-Bang J, Vinther J, Andersen CB, Lewin E, Olgaard K. Effect of chronic uremia on the transcriptional profile of the calcified aorta analyzed by RNA sequencing. Am J Physiol Renal Physiol 2016; 310:F477-91. [PMID: 26739890 DOI: 10.1152/ajprenal.00472.2015] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 01/05/2016] [Indexed: 12/12/2022] Open
Abstract
The development of vascular calcification (VC) in chronic uremia (CU) is a tightly regulated process controlled by factors promoting and inhibiting mineralization. Next-generation high-throughput RNA sequencing (RNA-seq) is a powerful and sensitive tool for quantitative gene expression profiling and the detection of differentially expressed genes. In the present study, we, for the first time, used RNA-seq to examine rat aorta transcriptomes from CU rats compared with control rats. Severe VC was induced in CU rats, which lead to extensive changes in the transcriptional profile. Among the 10,153 genes with an expression level of >1 reads/kilobase transcript/million mapped reads, 2,663 genes were differentially expressed with 47% upregulated genes and 53% downregulated genes in uremic rats. Significantly deregulated genes were enriched for ontologies related to the extracellular matrix, response to wounding, organic substance, and ossification. The individually affected genes were of relevance to osteogenic transformation, tissue calcification, and Wnt modulation. Downregulation of the Klotho gene in uremia is believed to be involved in the development of VC, but it is debated whether the effect is caused by circulating Klotho only or if Klotho is produced locally in the vasculature. We found that Klotho was neither expressed in the normal aorta nor calcified aorta by RNA-seq. In conclusion, we demonstrated extensive changes in the transcriptional profile of the uremic calcified aorta, which were consistent with a shift in phenotype from vascular tissue toward an osteochondrocytic transcriptome profile. Moreover, neither the normal vasculature nor calcified vasculature in CU expresses Klotho.
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Affiliation(s)
- Jakob L Rukov
- Faculty of Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Eva Gravesen
- Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Nephrological Department P, Rigshospitalet, Copenhagen, Denmark
| | - Maria L Mace
- Nephrological Department P, Rigshospitalet, Copenhagen, Denmark; Nephrological Department B, Herlev Hospital, Copenhagen, Denmark
| | | | - Jeppe Vinther
- Faculty of Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | | | - Ewa Lewin
- Nephrological Department P, Rigshospitalet, Copenhagen, Denmark; Nephrological Department B, Herlev Hospital, Copenhagen, Denmark
| | - Klaus Olgaard
- Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Nephrological Department P, Rigshospitalet, Copenhagen, Denmark;
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19
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Hu MC, Shi M, Zhang J, Addo T, Cho HJ, Barker SL, Ravikumar P, Gillings N, Bian A, Sidhu SS, Kuro-o M, Moe OW. Renal Production, Uptake, and Handling of Circulating αKlotho. J Am Soc Nephrol 2016; 27:79-90. [PMID: 25977312 PMCID: PMC4696570 DOI: 10.1681/asn.2014101030] [Citation(s) in RCA: 183] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 03/14/2015] [Indexed: 01/13/2023] Open
Abstract
αKlotho is a multifunctional protein highly expressed in the kidney. Soluble αKlotho is released through cleavage of the extracellular domain from membrane αKlotho by secretases to function as an endocrine/paracrine substance. The role of the kidney in circulating αKlotho production and handling is incompletely understood, however. Here, we found higher αKlotho concentration in suprarenal compared with infrarenal inferior vena cava in both rats and humans. In rats, serum αKlotho concentration dropped precipitously after bilateral nephrectomy or upon treatment with inhibitors of αKlotho extracellular domain shedding. Furthermore, the serum half-life of exogenous αKlotho in anephric rats was four- to five-fold longer than that in normal rats, and exogenously injected labeled recombinant αKlotho was detected in the kidney and in urine of rats. Both in vivo (micropuncture) and in vitro (proximal tubule cell line) studies showed that αKlotho traffics from the basal to the apical side of the proximal tubule via transcytosis. Thus, we conclude that the kidney has dual roles in αKlotho homeostasis, producing and releasing αKlotho into the circulation and clearing αKlotho from the blood into the urinary lumen.
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Affiliation(s)
- Ming Chang Hu
- Departments of Internal Medicine, Charles and Jane Pak Center of Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas;
| | - Mingjun Shi
- Charles and Jane Pak Center of Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas
| | | | | | - Han Ju Cho
- Charles and Jane Pak Center of Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Sarah L Barker
- Banting and Best Department of Medical Research and Department of Molecular Genetics, The Donnelly Centre, University of Toronto, Toronto, Ontario, Canada; and
| | - Priya Ravikumar
- Departments of Internal Medicine, Charles and Jane Pak Center of Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Nancy Gillings
- Charles and Jane Pak Center of Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Ao Bian
- Charles and Jane Pak Center of Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Sachdev S Sidhu
- Banting and Best Department of Medical Research and Department of Molecular Genetics, The Donnelly Centre, University of Toronto, Toronto, Ontario, Canada; and
| | - Makoto Kuro-o
- Charles and Jane Pak Center of Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas; Pathology, Center for Molecular Medicine, Jichi Medical University, Tochigi, Japan
| | - Orson W Moe
- Departments of Internal Medicine, Charles and Jane Pak Center of Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas; Physiology, and
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20
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Therapeutic potential of the endocrine fibroblast growth factors FGF19, FGF21 and FGF23. Nat Rev Drug Discov 2015; 15:51-69. [PMID: 26567701 DOI: 10.1038/nrd.2015.9] [Citation(s) in RCA: 307] [Impact Index Per Article: 34.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The endocrine fibroblast growth factors (FGFs), FGF19, FGF21 and FGF23, are critical for maintaining whole-body homeostasis, with roles in bile acid, glucose and lipid metabolism, modulation of vitamin D and phosphate homeostasis and metabolic adaptation during fasting. Given these functions, the endocrine FGFs have therapeutic potential in a wide array of chronic human diseases, including obesity, type 2 diabetes, cancer, and kidney and cardiovascular disease. However, the safety and feasibility of chronic endocrine FGF administration has been challenged, and FGF analogues and mimetics are now being investigated. Here, we discuss current knowledge of the complex biology of the endocrine FGFs and assess how this may be harnessed therapeutically.
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21
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Gigante M, Lucarelli G, Divella C, Netti GS, Pontrelli P, Cafiero C, Grandaliano G, Castellano G, Rutigliano M, Stallone G, Bettocchi C, Ditonno P, Gesualdo L, Battaglia M, Ranieri E. Soluble Serum αKlotho Is a Potential Predictive Marker of Disease Progression in Clear Cell Renal Cell Carcinoma. Medicine (Baltimore) 2015; 94:e1917. [PMID: 26559258 PMCID: PMC4912252 DOI: 10.1097/md.0000000000001917] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Renal cell carcinoma (RCC) accounts for approximately 3% of adult malignancies, and clear cell RCC (ccRCC), that has a high metastatic index and high relapse rate, is the most common histological subtype. The identification of new biomarkers in ccRCC is fundamental for stratifying patients into prognostic risk groups and to guide therapy. The renoprotective antiaging gene, αKlotho, has recently been found to work as a tumor suppressor in different human cancers. Here, we evaluated αKlotho expression in tissue and serum of ccRCC patients and correlated it with disease progression. Tissue αKlotho expression was studied by quantitative RT-PCR and immunohistochemistry. In addition, soluble serum αKlotho levels were preoperatively measured in 160 patients who underwent nephrectomy for RCC with ELISA. Estimates of cancer-specific (CSS) and progression-free survival (PFS) were calculated according to the Kaplan-Meier method. Multivariate analysis was performed to identify the most significant variables for predicting CSS and PFS. αKlotho protein levels were significantly decreased in RCC tissues compared with normal tissues (P < 0.01) and the more advanced the disease, the more evident the down-regulation. This trend was also observed in serum samples. Statistically significant differences resulted between serum αKlotho levels and tumor size (P = 0.003), Fuhrman grade (P = 0.007), and clinical stage (P = 0.0004). CSS and PFS were significantly shorter in patients with lower levels of αKlotho (P < 0.0001 and P = 0.0004, respectively). At multivariate analysis low serum levels of αKlotho were independent adverse prognostic factors for CSS (HR = 2.11; P = 0.03) and PFS (HR = 2.18; P = 0.03).These results indicate that a decreased αKlotho expression is correlated with RCC progression, and suggest a key role of declining αKlotho in the onset of cancer metastasis.
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Affiliation(s)
- Margherita Gigante
- From the Department of Emergency and Organ Transplantation - Nephrology, Dialysis and Transplantation Unit (MG, CD, CC, PP, GC, LG); Department of Emergency and Organ Transplantation, Urology, Andrology and Kidney Transplantation Unit, University of Bari, Bari (GL, MR, CB, PD, MB); Department of Medical and Surgical Sciences, Clinical Pathology, Nephrology, Dialysis and Transplantation Unit, University of Foggia, Foggia, Italy (GG, GS, ER)
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22
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Abstract
High circulating levels of fibroblast growth factor 23 (FGF23) have been demonstrated in kidney failure, but mechanisms of this are not well understood. Here we examined the impact of the kidney on the early regulation of intact FGF23 in acute uremia as induced by bilateral or unilateral nephrectomy (BNX and UNX, respectively) in the rat. BNX induced a significant increase in plasma intact FGF23 levels from 112 to 267 pg/ml within 15 min, which remained stable thereafter. UNX generated intact FGF23 levels between that seen in BNX and sham-operated rats. The intact to C-terminal FGF23 ratio was significantly increased in BNX rats. The rapid rise in FGF23 after BNX was independent of parathyroid hormone or FGF receptor signaling. No evidence of early stimulation of FGF23 gene expression in the bone was found. Furthermore, acute severe hyperphosphatemia or hypercalcemia had no impact on intact FGF23 levels in normal and BNX rats. The half-life of exogenous recombinant human FGF23 was significantly prolonged from 4.4 to 11.8 min in BNX rats. Measurements of plasma FGF23 in the renal artery and renal vein demonstrated a significant renal extraction. Thus the kidney is important in FGF23 homeostasis by regulation of its plasma level and metabolism.
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23
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Contemporary management of phosphorus retention in chronic kidney disease: a review. Clin Exp Nephrol 2015; 19:985-99. [DOI: 10.1007/s10157-015-1126-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 05/14/2015] [Indexed: 12/18/2022]
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Differential expression and regulation of Klotho by paricalcitol in the kidney, parathyroid, and aorta of uremic rats. Kidney Int 2015; 87:1141-52. [PMID: 25692955 PMCID: PMC4449811 DOI: 10.1038/ki.2015.22] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 11/21/2014] [Accepted: 12/11/2014] [Indexed: 12/29/2022]
Abstract
Klotho plays an important role in the pathogenesis of cardiovascular disease in chronic kidney disease (CKD). Klotho is highly expressed in the kidney and parathyroid glands, but its presence in the vasculature is debated. Renal Klotho is decreased in CKD, but the effect of uremia on Klotho in other tissues is not defined. The effect of vitamin D receptor activator therapy in CKD on expression of Klotho in various tissues is also in debate. In uremic rats (surgical 5/6th nephrectomy model), we compared 3-months of treatment with and without paricalcitol on Klotho immunostaining in the kidney, parathyroid glands and aorta. With uremia, Klotho was unchanged in the parathyroid, significantly decreased in the kidney (66%) and the intimal-medial area of the aorta (69%), and significantly increased in the adventitial area of the aorta (67%) compared with controls. Paricalcitol prevented the decrease in Klotho in the kidney, increased expression in the parathyroid (31%), had no effect in the aortic media, but blunted the increase of Klotho in aortic adventitia. We propose that fibroblasts are responsible for expression of Klotho in the adventitia. In hyperplastic human parathyroid tissue from uremic patients, Klotho was higher in oxyphil compared with chief cells. Thus, under our conditions of moderate CKD and mild-to-moderate hyperphosphatemia in rats, the differential expression of Klotho and its regulation by paricalcitol in uremia is tissue-dependent.
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Gravesen E, Mace ML, Hofman-Bang J, Olgaard K, Lewin E. Circulating FGF23 levels in response to acute changes in plasma Ca(2+). Calcif Tissue Int 2014; 95:46-53. [PMID: 24801007 DOI: 10.1007/s00223-014-9861-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Accepted: 04/15/2014] [Indexed: 12/20/2022]
Abstract
The regulation of fibroblast growth factor 23 (FGF23) synthesis and secretion is still incompletely understood. FGF23 is an important regulator of renal phosphate excretion and has regulatory effects on the calciotropic hormones calcitriol and parathyroid hormone (PTH). Calcium (Ca) and phosphate homeostasis are closely interrelated, and it is therefore likely that Ca is involved in FGF23 regulation. It has recently been reported that dietary Ca influenced FGF23 levels, with high Ca increasing FGF23. The mechanism remains to be clarified. It remains unknown whether acute changes in plasma Ca influence FGF23 levels and whether a close relationship, similar that known for Ca and PTH, exists between Ca and FGF23. Thus, the aim of the present study was to examine whether acute hypercalcemia and hypocalcemia regulate FGF23 levels in the rat. Acute hypercalcemia was induced by an intravenous Ca infusion and hypocalcemia by infusion of ethylene glycol tetraacetic acid (EGTA) in normal and acutely parathyroidectomized rats. Intact plasma FGF23 and intact plasma PTH and plasma Ca(2+) and phosphate were measured. Acute hypercalcemia and hypocalcemia resulted as expected in adequate PTH secretory responses. Plasma FGF23 levels remained stable at all plasma Ca(2+) levels; acute parathyroidectomy did not affect FGF23 secretion. In conclusion, Ca is not a regulator of acute changes in FGF23 secretion.
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Affiliation(s)
- Eva Gravesen
- Nephrological Department P, Rigshospitalet, University of Copenhagen, 2100, Copenhagen, Denmark
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Jimbo R, Shimosawa T. Cardiovascular Risk Factors and Chronic Kidney Disease-FGF23: A Key Molecule in the Cardiovascular Disease. Int J Hypertens 2014; 2014:381082. [PMID: 24678415 PMCID: PMC3941790 DOI: 10.1155/2014/381082] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 12/23/2013] [Indexed: 02/06/2023] Open
Abstract
Patients with chronic kidney disease (CKD) are at increased risk of mortality, mainly from cardiovascular disease. Moreover, abnormal mineral and bone metabolism, the so-called CKD-mineral and bone disorder (MBD), occurs from early stages of CKD. This CKD-MBD presents a strong cardiovascular risk for CKD patients. Discovery of fibroblast growth factor 23 (FGF23) has altered our understanding of CKD-MBD and has revealed more complex cross-talk and endocrine feedback loops between the kidney, parathyroid gland, intestines, and bone. During the past decade, reports of clinical studies have described the association between FGF23 and cardiovascular risks, left ventricular hypertrophy, and vascular calcification. Recent translational reports have described the existence of FGF23-Klotho axis in the vasculature and the causative effect of FGF23 on cardiovascular disease. These findings suggest FGF23 as a promising target for novel therapeutic approaches to improve clinical outcomes of CKD patients.
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Affiliation(s)
- Rika Jimbo
- Department of Internal Medicine, Odaira-Memorial Tokyo Hitachi Hospital, 3-5-7 Yushima, Bunkyo-ku, Tokyo, Japan
| | - Tatsuo Shimosawa
- Department of Clinical Laboratory, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan
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Jimbo R, Kawakami-Mori F, Mu S, Hirohama D, Majtan B, Shimizu Y, Yatomi Y, Fukumoto S, Fujita T, Shimosawa T. Fibroblast growth factor 23 accelerates phosphate-induced vascular calcification in the absence of Klotho deficiency. Kidney Int 2013; 85:1103-11. [PMID: 24088960 DOI: 10.1038/ki.2013.332] [Citation(s) in RCA: 136] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 06/12/2013] [Accepted: 06/13/2013] [Indexed: 02/06/2023]
Abstract
Fibroblast growth factor 23 (FGF23) is a phosphate-regulating hormone that acts primarily on the kidney and parathyroid. With declining kidney function there is an increase in circulating FGF23 levels, which is associated with vascular calcification and mortality in chronic kidney disease. Whether FGF23 exerts direct effects on vasculature is unclear. We evaluated the expression of Klotho and FGF receptors in rat aortic rings and rat aorta vascular smooth muscle cells maintained in culture by reverse transcription-PCR, western blotting, and immunostaining. Signaling pathways underlying FGF23 effects were assessed by western blotting, and effects of FGF23 on osteogenic markers and phosphate transporters were assessed by real-time reverse transcription-PCR. We detected Klotho and FGFR1 in total aorta but not in vascular smooth muscle cells. FGF23 augmented phosphate-induced vascular calcification in the aortic rings from uremic rats and dose dependently increased ERK1/2 phosphorylation in Klotho-overexpressing but not naive vascular smooth muscle cells. FGF23-induced ERK1/2 phosphorylation was inhibited by SU5402 (FGFR1 inhibitor) and U0126 (MEK inhibitor). FGF23 enhanced phosphate-induced calcification in Klotho-overexpressing vascular smooth muscle cells and increased osteoblastic marker expression, which was inhibited by U0126. In contrast, phosphate transporter expression was not affected by phosphate or FGF23. Thus, FGF23 enhances phosphate-induced vascular calcification by promoting osteoblastic differentiation involving the ERK1/2 pathway.
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Affiliation(s)
- Rika Jimbo
- Department of Nephrology and Endocrinology, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Fumiko Kawakami-Mori
- Department of Nephrology and Endocrinology, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Shengyu Mu
- Division of Clinical Epigenetics, Research Center for Advanced Science and Technology (RCAST), University of Tokyo, Meguro-ku, Tokyo, Japan
| | - Daigoro Hirohama
- Department of Nephrology and Endocrinology, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Bohumil Majtan
- Department of Cardiology and Angiology, Frankenwaldklinik Kronach, Bavaria,Germany
| | - Yuichiro Shimizu
- Department of Nephrology and Endocrinology, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Yutaka Yatomi
- Department of Clinical Laboratory, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Seiji Fukumoto
- Department of Nephrology and Endocrinology, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Toshiro Fujita
- Division of Clinical Epigenetics, Research Center for Advanced Science and Technology (RCAST), University of Tokyo, Meguro-ku, Tokyo, Japan
| | - Tatsuo Shimosawa
- Department of Clinical Laboratory, Graduate School of Medicine, University of Tokyo, Bunkyo-ku, Tokyo, Japan
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Silver J, Naveh-Many T. FGF-23 and secondary hyperparathyroidism in chronic kidney disease. Nat Rev Nephrol 2013; 9:641-9. [PMID: 23877588 DOI: 10.1038/nrneph.2013.147] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The metabolic changes that occur in patients with chronic kidney disease (CKD) have a profound influence on mineral and bone metabolism. CKD results in altered levels of serum phosphate, vitamin D, calcium, parathyroid hormone (PTH) and fibroblast growth factor 23 (FGF-23); the increased levels of serum phosphate, PTH and FGF-23 contribute to the increased cardiovascular mortality in affected patients. FGF-23 is produced by osteocytes and osteoblasts and acts physiologically in the kidney to induce phosphaturia and inhibit the synthesis of 1,25-dihydroxyvitamin D3. PTH acts directly on osteocytes to increase FGF-23 expression. In addition, the high levels of PTH associated with CKD contribute to changes in bone remodelling that result in decreased levels of dentin matrix protein 1 and the release of low-molecular-weight fibroblast growth factors from the bone matrix, which stimulate FGF-23 transcription. A prolonged oral phosphorus load increases FGF-23 expression by a mechanism that includes local changes in the ratio of inorganic phosphate to pyrophosphate in bone. Other factors such as dietary vitamin D compounds, calcium, and metabolic acidosis all increase FGF-23 levels. This Review discusses the mechanisms by which secondary hyperparathyroidism associated with CKD stimulates bone cells to overexpress FGF-23 levels.
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Affiliation(s)
- Justin Silver
- Hadassah Hebrew University Medical Center, Minerva Center for Calcium and Bone Metabolism, Nephrology, Ein Karem, Jerusalem 91120, Israel
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Abstract
Phosphorus is a common anion. It plays an important role in energy generation. Renal phosphate handling is regulated by three organs parathyroid, kidney and bone through feedback loops. These counter regulatory loops also regulate intestinal absorption and thus maintain serum phosphorus concentration in physiologic range. The parathyroid hormone, vitamin D, Fibrogenic growth factor 23 (FGF23) and klotho coreceptor are the key regulators of phosphorus balance in body.
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Affiliation(s)
- Narayan Prasad
- Department of Nephrology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India
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Abstract
Through alternative splicing, Klotho protein exists both as a secreted and a membrane form whose extracellular domain could be shed from the cell surface by secretases and released into the circulation to act as endocrine factor. Unlike membrane Klotho which functions as a coreceptor for fibroblast growth factor-23 (FGF23) to modulate FGF23 signal transduction, soluble Klotho is a multifunction protein present in the biological fluids including blood, urine and cerebrospinal fluid and plays important roles in antiaging, energy metabolism, inhibition of Wnt signaling, antioxidation, modulation of ion transport, control of parathyroid hormone and 1,25(OH)2VD3 production, and antagonism of renin-angiotensin-aldosterone system. Emerging evidence from clinical and basic studies reveal that chronic kidney disease is a state of endocrine and renal Klotho deficiency, which may serve as an early biomarker and a pathogenic contributor to chronic progression and complications in chronic kidney disease including vascular calcification, cardiac hypertrophy, and secondary hyperparathyroidism. Supplementation of exogenous Klotho and/or upregulation of endogenous Klotho production by using rennin angiotensin system inhibitors, HMG CoA reductase inhibitors, vitamin D analogues, peroxisome proliferator-activated receptors-gamma agonists, or anti-oxidants may confer renoprotection from oxidation and suppression of renal fibrosis, and also on prevention or alleviation of complications in chronic kidney disease. Therefore, Klotho is a highly promising candidate on the horizon as an early biomarker, and as a novel therapeutic agent for chronic kidney disease.
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Affiliation(s)
- Ming Chang Hu
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Makoto Kuro-o
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Orson W. Moe
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX, USA
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Drüeke TB, Olgaard K. Report on 2012 ISN Nexus Symposium: ‘Bone and the Kidney’. Kidney Int 2013; 83:557-62. [DOI: 10.1038/ki.2012.453] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Abstract
Klotho is a single-pass transmembrane protein highly expressed in the kidney. Membrane Klotho protein acts as a co-receptor for fibroblast growth factor-23. Its extracellular domain is shed from the cell surface and functions as an endocrine substance that exerts multiple renal and extrarenal functions. An exhaustive review is beyond the scope and length of this article; thus, only effects with pertinence to mineral metabolism and renoprotection are highlighted here. Klotho participates in mineral homeostasis via interplay with other calciophosphoregulatory hormones (parathyroid hormone, fibroblast growth factor-23, and 1,25-[OH]2 vitamin D3) in kidney, bone, intestine, and parathyroid gland. Klotho also may be involved in acute and chronic kidney disease development and progression. Acute kidney injury is a temporary and reversible state of Klotho deficiency and chronic kidney disease is a sustained state of systemic Klotho deficiency. Klotho deficiency renders the kidney more susceptible to acute insults, delays kidney regeneration, and promotes renal fibrosis. In addition to direct renal effects, Klotho deficiency also triggers and aggravates deranged mineral metabolism, secondary hyperparathyroidism, vascular calcification, and cardiac hypertrophy and fibrosis. Although studies examining the therapeutic effect of Klotho replacement were performed in animal models, it is quite conceivable that supplementation of exogenous Klotho and/or up-regulation of endogenous Klotho production may be a viable therapeutic strategy for patients with acute or chronic kidney diseases.
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Affiliation(s)
- Ming Chang Hu
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390-8885, USA.
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Frick KK, Asplin JR, Favus MJ, Culbertson C, Krieger NS, Bushinsky DA. Increased biological response to 1,25(OH)(2)D(3) in genetic hypercalciuric stone-forming rats. Am J Physiol Renal Physiol 2013; 304:F718-26. [PMID: 23344574 DOI: 10.1152/ajprenal.00645.2012] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Genetic hypercalciuric stone-forming (GHS) rats, bred to maximize urine (U) calcium (Ca) excretion, have increased intestinal Ca absorption and bone Ca resorption and reduced renal Ca reabsorption, leading to increased UCa compared with the Sprague-Dawley (SD) rats. GHS rats have increased vitamin D receptors (VDR) at each of these sites, with normal levels of 1,25(OH)(2)D(3) (1,25D), indicating that their VDR is undersaturated with 1,25D. We tested the hypothesis that 1,25D would induce a greater increase in UCa in GHS rats by feeding both strains ample Ca and injecting 1,25D (25 ng · 100 g body wt(-1) · day(-1)) or vehicle for 16 days. With 1,25D, UCa in SD increased from 1.7 ± 0.3 mg/day to 24.4 ± 1.2 (Δ = 22.4 ± 1.5) and increased more in GHS from 10.5 ± 0.7 to 41.9 ± 0.7 (Δ = 29.8 ± 1.8; P = 0.003). To determine the mechanism of the greater increase in UCa in GHS rats, we measured kidney RNA expression of components of renal Ca transport. Expression of transient receptor potential vanilloid (TRPV)5 and calbindin D(28K) were increased similarly in SD + 1,25D and GHS + 1,25D. The Na(+)/Ca(2+) exchanger (NCX1) was increased in GHS + 1,25D. Klotho was decreased in SD + 1,25D and GHS + 1,25D. TRPV6 was increased in SD + 1,25D and increased further in GHS + 1,25D. Claudin 14, 16, and 19, Na/K/2Cl transporter (NKCC2), and secretory K channel (ROMK) did not differ between SD + 1,25D and GHS + 1,25D. Increased UCa with 1,25D in GHS exceeded that of SD, indicating that the increased VDR in GHS induces a greater biological response. This increase in UCa, which must come from the intestine and/or bone, must exceed any effect of 1,25D on TRPV6 or NCX1-mediated renal Ca reabsorption.
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Affiliation(s)
- Kevin K Frick
- Division of Nephrology, Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA.
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Heine GH, Seiler S, Fliser D. FGF-23: the rise of a novel cardiovascular risk marker in CKD. Nephrol Dial Transplant 2013; 27:3072-81. [PMID: 22851630 DOI: 10.1093/ndt/gfs259] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Elevated plasma levels of the phosphaturic hormone fibroblast growth factor 23 (FGF-23) are a hallmark of chronic kidney disease (CKD)-mineral and bone disorder. FGF-23 allows serum phosphate levels within physiological limits to be maintained in progressive CKD until end-stage renal disease is reached. Despite its seemingly beneficial role in phosphate homeostasis, several prospective studies in dialysis patients and in patients with less advanced CKD associated elevated FGF-23 with poor cardiovascular and renal outcome. Moreover, very recent evidence suggests an adverse prognostic impact of elevated FGF-23 even in subjects without manifest CKD. These epidemiological data are supplemented by laboratory findings that reveal a pathophysiological role of FGF-23 in the pathogenesis of myocardial injury. In aggregate, these clinical and experimental data identify FGF-23 as a promising target of novel therapeutic interventions in CKD and beyond, which should be tested in future clinical trials.
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Affiliation(s)
- Gunnar H Heine
- Department of Internal Medicine IV—Nephrology and Hypertension, Saarland University Medical Center, Homburg/Saar, Germany.
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Gravesen E, Hofman-Bang J, Lewin E, Olgaard K. Ergocalciferol treatment and aspects of mineral homeostasis in patients with chronic kidney disease stage 4-5. Scand J Clin Lab Invest 2013; 73:107-16. [PMID: 23281842 DOI: 10.3109/00365513.2012.744464] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Focus on non-classical effects and possible less side effects of treatment with nutritional vitamin D, raises the expectation of possible benefits from treating chronic kidney disease (CKD) patients with ergocalciferol (vitamin D2). Treatment with 1,25(OH)2 vitamin D (calcitriol) induces elevated fibroblast growth factor 23 (FGF23), while epidemiological studies have found positive effects of nutritional and 25(OH)vitamin D on mortality in CKD. Disturbed mineral homeostasis in CKD is correlated to adverse outcome and cardiovascular mortality. The objective was to examine the possible effects of treatment with high doses of ergocalciferol on parameters of mineral homeostasis in predialysis CKD patients. METHODS A total of 43 adult patients with CKD stage 4-5, not receiving vitamin D supplementation, were studied, and allocated by simple randomization to either an intervention (n = 26) or a control group (n = 17). The intervention group received ergocalciferol, 50.000 IU/week for 6 weeks. Plasma FGF23, creatinine, parathyroid hormone (PTH), phosphate and ionized calcium were obtained at baseline and after the 6 weeks. RESULTS The intervention group had a significant increase in 25(OH)D2 concentration from < 10 to 90 ± 4 nmol/L, while 1,25(OH)2D (62 ± 6 at baseline and 67 ± 6 pmol/L at 6 weeks) remained stable. No changes were seen in the circulating vitamin D concentrations in the control group. After the 6 weeks of treatment no significant changes were seen in concentration of creatinine, phosphate, ionized calcium, PTH and FGF23 remained stable. CONCLUSION No harmful effects of short-term treatment with high-dose ergocalciferol were observed on markers of mineral homeostasis and FGF23 in CKD patients stage 4-5.
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Affiliation(s)
- Eva Gravesen
- University of Copenhagen, Nephrological Department P, Rigshospitalet, Copenhagen, Denmark
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Pavik I, Jaeger P, Ebner L, Wagner CA, Petzold K, Spichtig D, Poster D, Wüthrich RP, Russmann S, Serra AL. Secreted Klotho and FGF23 in chronic kidney disease Stage 1 to 5: a sequence suggested from a cross-sectional study. Nephrol Dial Transplant 2012; 28:352-9. [PMID: 23129826 DOI: 10.1093/ndt/gfs460] [Citation(s) in RCA: 164] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Klotho and fibroblast growth factor 23 (FGF23) are key regulators of mineral metabolism in renal insufficiency. FGF23 levels have been shown to increase early in chronic kidney disease (CKD); however, the corresponding soluble Klotho levels at the different CKD stages are not known. METHODS Soluble Klotho, FGF23, parathyroid hormone (PTH), 1,25-dihydroxy vitamin D(3) (1,25D) and other parameters of mineral metabolism were measured in an observational cross-sectional study in 87 patients. Locally weighted scatter plot smoothing function of these parameters were plotted versus estimated glomerular filtration rate (eGFR) to illustrate the pattern of the relationship. Linear and non-linear regression analyses were performed to estimate changes in mineral metabolism parameters per 1mL/min/1.73 m(2) decline. RESULTS In CKD 1-5, Klotho and 1,25D linearly decreased, whereas both FGF23 and PTH showed a baseline at early CKD stages and then a curvilinear increase. Crude mean Klotho level declined by 4.8 pg/mL (95% CI 3.5-6.2 pg/mL, P < 0.0001) and 1,25D levels by 0.30 ng/L (95% CI 0.18-0.41 ng/L, P < 0.0001) as GFR declined by 1 mL/min/1.73 m(2). After adjustment for age, gender, serum 25-hydroxyvitamin D levels and concomitant medications (calcium, supplemental vitamin D and calcitriol), we estimated that the mean Klotho change was 3.2 pg/mL (95% CI 1.2-5.2 pg/mL, P = 0.0019) for each 1 mL/min/1.73 m(2) GFR change. FGF23 departed from the baseline at an eGFR of 47 mL/min/1.73 m(2) (95% CI 39-56 mL/min/1.73 m(2)), whereas PTH departed at an eGFR of 34 mL/min/1.73 m(2) (95% CI 19-50 mL/min/1.73 m(2)). CONCLUSIONS Soluble Klotho and 1,25D levels decrease and FGF23 levels increase at early CKD stages, whereas PTH levels increase at more advanced CKD stages.
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Affiliation(s)
- Ivana Pavik
- Institute of Physiology and Zurich Center for Integrative Human Physiology, Zurich, Switzerland
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Epigenetic Methylation of Parathyroid CaR and VDR Promoters in Experimental Secondary Hyperparathyroidism. Int J Nephrol 2012; 2012:123576. [PMID: 23094155 PMCID: PMC3474253 DOI: 10.1155/2012/123576] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Accepted: 09/04/2012] [Indexed: 11/25/2022] Open
Abstract
Secondary hyperparathyroidism (s-HPT) in uremia is characterized by decreased expression in the parathyroids of calcium sensing (CaR) and vitamin D receptors (VDR). Parathyroid hormone (PTH) is normalized despite low levels of CaR and VDR after experimental reversal of uremia. The expression of CaR in parathyroid cultures decreases rapidly. Methylation of promoter regions is often detected during epigenetic downregulation of gene expression. Therefore, using an experimental rat model, we examined changes in methylation levels of parathyroid CaR and VDR promoters in vivo and in vitro. Methods. Uremia was induced by 5/6 nephrectomy. Melting temperature profiling of CaR and VDR PCR products after bisulfite treatment of genomic DNA from rat parathyroids was performed. Real-time PCR measured expression of PTH, CaR, VDR, and klotho genes in vitro. Results. Parathyroids from uremic rats had similar low levels of methylation in vivo and in vitro. In culture, a significant downregulation of CaR, VDR, and klotho within two hours of incubation was observed, while housekeeping genes remained stable for 24 hours. Conclusion. In uremic s-HPT and in vitro, no overall changes in methylation levels in the promoter regions of parathyroid CaR and VDR genes were found. Thus, epigenetic methylation of these promoters does not explain decreased parathyroid expression of CaR and VDR genes in uremic s-HPT.
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Marckmann P, Agerskov H, Thineshkumar S, Bladbjerg EM, Sidelmann JJ, Jespersen J, Nybo M, Rasmussen LM, Hansen D, Scholze A. Randomized controlled trial of cholecalciferol supplementation in chronic kidney disease patients with hypovitaminosis D. Nephrol Dial Transplant 2012; 27:3523-31. [PMID: 22822092 DOI: 10.1093/ndt/gfs138] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Hypovitaminosis D is common in chronic kidney disease (CKD). Effects of 25-hydroxyvitamin D replenishment in CKD are not well described. METHODS An 8-week randomized, placebo-controlled, double-blind parallel intervention study was conducted in haemodialysis (HD) and non-HD CKD patients. Treatment consisted of 40,000 IU of cholecalciferol orally per week. Plasma 25-hydroxyvitamin D (25-OHD), plasma 1,25-dihydroxyvitamin D (1,25-diOHD), plasma parathyroid hormone (PTH), serum phosphate, ionized serum calcium and serum fibroblast growth factor 23 (FGF-23) were analysed. We also investigated biomarkers related to cardiovascular disease (plasma D-dimer, plasma fibrinogen, plasma von Willebrand factor antigen and activity, plasma interleukin 6, plasma C-reactive protein, blood pressure, aortic augmentation index, aortic pulse wave velocity and 24-h urinary protein loss). Objective and subjective health variables were assessed (muscle function tests, visual analogue scores and Health Assessment Questionnaire). RESULTS Fifty-two CKD patients with 25-OHD <50 nmol/L at screening were included. Cholecalciferol supplementation led to a significant increase to a median of 155 nmol/L 25-OHD (interquartile range 137-173 nmol/L) in treated patients (n = 25, P < 0.001). In non-HD patients, we saw a significant increase in 1,25-diOHD (n = 13, P < 0.01) and a lowering of PTH (n = 13, P < 0.001). This was not observed in HD patients. Cholecalciferol supplementation caused a significant increase in serum calcium and FGF-23. CONCLUSIONS 25-OHD replenishment was effectively obtained with the employed cholecalciferol dosing. In non-HD patients, it had favourable effects on 1,25-diOHD and PTH. Vitamin D-supplemented patients must be monitored for hypercalcaemia. The present study could not identify significant pleiotropic effects of 25-OHD replenishment.
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Affiliation(s)
- Peter Marckmann
- Clinical Research Unit, Department of Nephrology, Odense University Hospital, Odense, Denmark.
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The role of the calcium-sensing receptor in human disease. Clin Biochem 2012; 45:943-53. [PMID: 22503956 DOI: 10.1016/j.clinbiochem.2012.03.034] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Revised: 03/22/2012] [Accepted: 03/27/2012] [Indexed: 01/18/2023]
Abstract
Following the discovery of the calcium-sensing receptor (CaSR) in 1993, its pivotal role in disorders of calcium homeostasis such as Familial Hypocalciuric Hypercalcemia (FHH) was quickly demonstrated. Since then, it has become clear that the CaSR has immense functional versatility largely through its ability to activate many different signaling pathways in a ligand- and tissue-specific manner. This allows the receptor to play diverse and crucial roles in human physiology and pathophysiology, both in calcium homeostasis and in tissues and biological processes unrelated to calcium balance. This review covers current knowledge of the role of the CaSR in disorders of calcium homeostasis (FHH, neonatal severe hyperparathyroidism, autosomal dominant hypocalcemia, primary and secondary hyperparathyroidism, hypercalcemia of malignancy) as well as unrelated diseases such as breast and colorectal cancer (where the receptor appears to play a tumor suppressor role), Alzheimer's disease, pancreatitis, diabetes mellitus, hypertension and bone and gastrointestinal disorders. In addition, it examines the use or potential use of CaSR agonists or antagonists (calcimimetics and calcilytics) and other drugs mediated through the CaSR, in the management of disorders as diverse as hyperparathyroidism, osteoporosis and gastrointestinal disease.
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Román-García P, Carrillo-López N, Naves-Díaz M, Rodríguez I, Ortiz A, Cannata-Andía JB. Dual-specificity phosphatases are implicated in severe hyperplasia and lack of response to FGF23 of uremic parathyroid glands from rats. Endocrinology 2012; 153:1627-37. [PMID: 22334717 DOI: 10.1210/en.2011-1770] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Phosphate load accelerates the progression of secondary hyperparathyroidism (sHPT). In advanced stages of sHPT, there is a marked hyperplasia and resistance to classical regulatory endocrine factors such as calcium, calcitriol, or fibroblast growth factor 23 (FGF23), which suppresses PTH secretion by an ERK-dependent mechanism. Nephrectomized rats were fed with a high- or normal-phosphorus diet for different periods of time to induce sHPT. Biochemical parameters, parathyroid gland microarrays, quantitative real-time PCR, and immunohistochemistry (ERK/phospho-ERK) were performed. To test the role of dual-specificity phosphatases (Dusp) on parathyroid gland regulation, normal parathyroid glands were cultured with FGF23 and Dusp. Uremic rats fed with a high-phosphorus diet showed more severe sHPT, higher serum FGF23 levels and mortality, and decreased parathyroid Klotho gene expression. In all stages of sHPT, parathyroid microarrays displayed a widespread gene expression down-regulation; only a few genes were overexpressed, among them, Dusp5 and -6. In very severe sHPT, a significant reduction in phospho-ERK (the target of Dusp) and a significant increase of Dusp5 and -6 gene expression were observed. In ex vivo experiments with parathyroid glands, Dusp partially blocked the effect of FGF23 on PTH secretion, suggesting that Dusp might play a role in parathyroid regulation. The overexpression of Dusp and the inactivation of ERK found in the in vivo studies together with the ex vivo results might be indicative of the defense mechanism triggered to counteract hyperplasia, a mechanism that can also contribute to the resistance to the effect of FGF23 on parathyroid gland observed in advanced forms of chronic kidney disease.
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Affiliation(s)
- Pablo Román-García
- Servicio de Metabolismo Óseo y Mineral, Instituto Reina Sofía de Investigaciones Nefrológicas, Hospital Universitario Central de Asturias, 33006 Oviedo, Asturias, Spain
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Imanishi Y, Nagata Y, Inaba M. Parathyroid diseases and animal models. Front Endocrinol (Lausanne) 2012; 3:78. [PMID: 22754549 PMCID: PMC3384071 DOI: 10.3389/fendo.2012.00078] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2012] [Accepted: 05/31/2012] [Indexed: 11/13/2022] Open
Abstract
CIRCULATING CALCIUM AND PHOSPHATE ARE TIGHTLY REGULATED BY THREE HORMONES: the active form of vitamin D (1,25-dihydroxyvitamin D), fibroblast growth factor (FGF)-23, and parathyroid hormone (PTH). PTH acts to stimulate a rapid increment in serum calcium and has a crucial role in calcium homeostasis. Major target organs of PTH are kidney and bone. The oversecretion of the hormone results in hypercalcemia, caused by increased intestinal calcium absorption, reduced renal calcium clearance, and mobilization of calcium from bone in primary hyperparathyroidism. In chronic kidney disease, secondary hyperparathyroidism of uremia is observed in its early stages, and this finally develops into the autonomous secretion of PTH during maintenance hemodialysis. Receptors in parathyroid cells, such as the calcium-sensing receptor, vitamin D receptor, and FGF receptor (FGFR)-Klotho complex have crucial roles in the regulation of PTH secretion. Genes such as Cyclin D1, RET, MEN1, HRPT2, and CDKN1B have been identified in parathyroid diseases. Genetically engineered animals with these receptors and the associated genes have provided us with valuable information on the patho-physiology of parathyroid diseases. The application of these animal models is significant for the development of new therapies.
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Affiliation(s)
- Yasuo Imanishi
- Department of Metabolism, Endocrinology and Molecular Medicine, Osaka City University Graduate School of MedicineOsaka, Japan
- *Correspondence: Yasuo Imanishi, Department of Metabolism, Endocrinology and Molecular Medicine, Osaka City University Graduate School of Medicine, 1-4-3, Asahi-machi, Abeno-ku, Osaka 545-8585, Japan. e-mail:
| | - Yuki Nagata
- Department of Metabolism, Endocrinology and Molecular Medicine, Osaka City University Graduate School of MedicineOsaka, Japan
| | - Masaaki Inaba
- Department of Metabolism, Endocrinology and Molecular Medicine, Osaka City University Graduate School of MedicineOsaka, Japan
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Secreted klotho and chronic kidney disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 728:126-57. [PMID: 22396167 DOI: 10.1007/978-1-4614-0887-1_9] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Soluble Klotho (sKl) in the circulation can be generated directly by alterative splicing of the Klotho transcript or the extracellular domain of membrane Klotho can be released from membrane-anchored Klotho on the cell surface. Unlike membrane Klotho which functions as a coreceptor for fibroblast growth factor-23 (FGF23), sKl, acts as hormonal factor and plays important roles in anti-aging, anti-oxidation, modulation of ion transport, and Wnt signaling. Emerging evidence reveals that Klotho deficiency is an early biomarker for chronic kidney diseases as well as a pathogenic factor. Klotho deficiency is associated with progression and chronic complications in chronic kidney disease including vascular calcification, cardiac hypertrophy, and secondary hyperparathyroidism. In multiple experimental models, replacement of sKl, or manipulated up-regulation of endogenous Klotho protect the kidney from renal insults, preserve kidney function, and suppress renal fibrosis, in chronic kidney disease. Klotho is a highly promising candidate on the horizon as an early biomarker, and as a novel therapeutic agent for chronic kidney disease.
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Bienaimé F, Prié D, Friedlander G, Souberbielle JC. Vitamin D metabolism and activity in the parathyroid gland. Mol Cell Endocrinol 2011; 347:30-41. [PMID: 21664247 DOI: 10.1016/j.mce.2011.05.031] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Revised: 05/05/2011] [Accepted: 05/06/2011] [Indexed: 12/21/2022]
Abstract
Parathormone (PTH) and vitamin D are two critical hormonal regulators of calcium homeostasis. An important cross-talk exists between the PTH and vitamin D hormonal systems. PTH enhances vitamin D hydroxylation on carbon 1 in kidney cells thereby allowing the systemic release of 1-25-dihydroxy-vitamin D, which represents the fully active hormone. Conversely, parathyroid gland represents a direct target for vitamin D. Parathyroid cells express the vitamin D receptor and the 1-α-hydroxylase enzyme, which allows the local formation of 1-25-dihydroxy-vitamin D. Because of its potential implication in several diseases, including osteoporosis or chronic kidney disease, the interplay between PTH and vitamin D has received considerable attention these last two decades. The aim of this review is to summarize our current understanding of the molecular basis of vitamin D action and metabolism in parathyroid cells. The potential clinical implications of the recent advances made in this field will also be discussed.
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Affiliation(s)
- Frank Bienaimé
- Service de Physiologie - Explorations Fonctionnelles, Hôpital Necker Enfants Malades, 149 Rue de Sèvres, 75015 Paris, France
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Tang C, Pathare G, Michael D, Fajol A, Eichenmüller M, Lang F. Downregulation of Klotho expression by dehydration. Am J Physiol Renal Physiol 2011; 301:F745-50. [PMID: 21734097 DOI: 10.1152/ajprenal.00037.2011] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Klotho, a transmembrane protein, protease, and hormone mainly expressed in renal tissue counteracts aging. Overexpression of Klotho substantially prolongs the life span. Klotho deficiency leads to excessive formation of 1,25(OH)(2)D(3), growth deficit, accelerated aging, and early death. Aging is frequently paralleled by dehydration, which is considered to accelerate the development of age-related disorders. The present study explored the possibility that dehydration influences Klotho expression. Klotho transcript levels were determined by RT-PCR, and Klotho protein abundance was detected by Western blotting in renal tissue from hydrated and 36-h-dehydrated mice as well as in human embryonic kidney (HEK293) cells. Dehydration was followed by a significant decline of renal Klotho transcript levels and protein abundance, accompanied by an increase in plasma osmolarity as well as plasma ADH, aldosterone, and 1,25(OH)(2)D(3) levels. Antidiuretic hormone (ADH; 50 nM) and aldosterone (1 μM) significantly decreased Klotho transcription and protein expression in HEK293 cells. In conclusion, the present observations disclose a powerful effect of dehydration on Klotho expression, an effect at least partially mediated by enhanced release of ADH and aldosterone.
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The secretory response of parathyroid hormone to acute hypocalcemia in vivo is independent of parathyroid glandular sodium/potassium-ATPase activity. Kidney Int 2011; 79:742-8. [DOI: 10.1038/ki.2010.501] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Huang CL, Moe OW. Klotho: a novel regulator of calcium and phosphorus homeostasis. Pflugers Arch 2011; 462:185-93. [DOI: 10.1007/s00424-011-0950-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Revised: 02/25/2011] [Accepted: 02/27/2011] [Indexed: 01/14/2023]
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Razzaque MS. Osteo-renal regulation of systemic phosphate metabolism. IUBMB Life 2011; 63:240-7. [PMID: 21438115 DOI: 10.1002/iub.437] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Accepted: 01/29/2011] [Indexed: 01/29/2023]
Abstract
Impaired kidney function and subsequent skeletal responses play a critical role in disrupting phosphate balance in chronic kidney disease (CKD) patients with mineral and bone disorder (CKD-MBD). In patients with CKD-MBD, the inability of the kidney to maintain normal mineral ion balance affects bone remodeling to induce skeletal fracture and extraskeletal vascular calcification. In physiological conditions, bone-derived fibroblast growth factor 23 (FGF23) acts on the kidney to reduce serum phosphate and 1,25-dihydroxyvitamin D levels. In humans, increased bioactivity of FGF23 leads to increased urinary phosphate excretion, which induces hypophosphatemic diseases (e.g., rickets/osteomalacia). However, reduced FGF23 activity is associated with hyperphosphatemic diseases (e.g., tumoral calcinosis). In patients with CKD, high serum levels of FGF23 fail to reduce serum phosphate levels and lead to numerous complications, including vascular calcification, one of the important determinants of mortality of CKD-MBD patients. Of particular significance, molecular, biochemical and morphological changes in patients with CKD-MBD are mostly due to osteo-renal dysregulation of mineral ion metabolism. Furthermore, hyperphosphatemia can partly contribute to the development of secondary hyperparathyroidism in patients with CKD-MBD. Relatively new pharmacological agents including sevelamer hydrochloride, calcitriol analogs and cinacalcet hydrochloride are used either alone, or in combination, to minimize hyperphosphatemia and hyperparathyroidism associated complications to improve morbidity and mortality of CKD-MBD patients. This article will briefly summarize how osteo-renal miscommunication can induce phosphate toxicity, resulting in extensive tissue injuries.
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Affiliation(s)
- Mohammed Shawkat Razzaque
- Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA, USA.
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Cheng CY, Kuro-o M, Razzaque MS. Molecular regulation of phosphate metabolism by fibroblast growth factor-23-klotho system. Adv Chronic Kidney Dis 2011; 18:91-7. [PMID: 21406293 DOI: 10.1053/j.ackd.2010.11.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Revised: 11/11/2010] [Accepted: 11/30/2010] [Indexed: 11/11/2022]
Abstract
Phosphorus is an essential nutrient and is routinely assimilated through consumption of food. The body's need of phosphate is usually fulfilled by intestinal absorption of this element from the consumed food, whereas its serum level is tightly regulated by renal excretion or reabsorption. Sodium-dependent phosphate transporters, located in the luminal side of the proximal tubular epithelial cells, have a molecular control on renal phosphate excretion and reabsorption. The systemic regulation of phosphate metabolism is a complex multiorgan process, and the identification of fibroblast growth factor-23 (FGF23)-Klotho system as a potent phosphatonin has provided new mechanistic insights into the homeostatic control of phosphate. Hypophosphatemia as a result of an increase in urinary phosphate wasting after activation of the FGF23-Klotho system is a common phenomenon, observed in both animal and human studies, whereas suppression of the FGF23-Klotho system leads to the development of hyperphosphatemia. This article will briefly summarize how delicate interactions of the FGF23-klotho system can regulate systemic phosphate homeostasis.
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