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Yu S, Sun J, Guo X. Efficacy and safety of tenapanor in end-stage renal disease patients with hyperphosphatemia: a systematic review and meta-analysis. Ren Fail 2024; 46:2410389. [PMID: 39351794 PMCID: PMC11445914 DOI: 10.1080/0886022x.2024.2410389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2024] [Revised: 09/06/2024] [Accepted: 09/24/2024] [Indexed: 10/03/2024] Open
Abstract
BACKGROUND Hyperphosphatemia occurs universally in end-stage renal disease(ESRD), and the attainment of target serum phosphate levels remains suboptimal with currently available phosphate binders. This meta-analysis aimed to evaluate the efficacy and safety of tenapanor in end-stage renal disease patients with hyperphosphatemia. METHODS Data sources included PubMed, Embase, Web of Science, and Cochrane Library. This meta-analysis included randomized controlled trials evaluating both the efficacy of tenapanor in reducing serum phosphate levels and its safety profile. The risk of bias was assessed using the Cochrane risk of bias tool for RCTs. The GRADE system was used to assess the overall certainty of evidence. A meta-analysis was carried out by using fixed effects (I2 values < 50%) or random effects (I2 values ≥ 50%) models to calculate MD with 95% CI for continuous outcome variables and RR with 95% CI for dichotomous variables. Publication bias was evaluated using funnel plots. RESULTS A total of seven RCTs involving 877 individuals were included. The pooling analysis demonstrates that the reduction in mean serum phosphorus levels in the tenapanor group was significantly greater than that in the placebo group [MD= -1.06 mg/dl, 95% CI (-1.59, -0.53); I2 = 83%, p < 0.0001]. The proportion of patients achieving a serum phosphorus level of < 5.5 mg/dL, along with the incidence of any adverse events (AEs) and gastrointestinal disorders, was higher in the tenapanor group compared to the placebo group. CONCLUSION Tenapanor has the potential to significantly reduce serum phosphorus levels and enhance the rate of achieving target levels compared to placebo, all while maintaining an acceptable safety and tolerability profile. REGISTRATION PROSPERO registration number CRD42024544531.
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Affiliation(s)
- Shanshen Yu
- First People’s Hospital of Linping District, Hangzhou, Zhejiang, China
| | - Jia Sun
- First People’s Hospital of Linping District, Hangzhou, Zhejiang, China
| | - Xiafei Guo
- First People’s Hospital of Linping District, Hangzhou, Zhejiang, China
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2
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Ratsma DMA, Muller M, Koedam M, Zillikens MC, van der Eerden BCJ. A role for sirtuin 1 in FGF23 activation following β-glycerophosphate treatment. Pflugers Arch 2024; 476:1279-1288. [PMID: 38772920 PMCID: PMC11271368 DOI: 10.1007/s00424-024-02974-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 04/30/2024] [Accepted: 05/15/2024] [Indexed: 05/23/2024]
Abstract
Phosphate homeostasis is vital for many biological processes and disruptions in circulating levels can be detrimental. While the mechanisms behind FGF23 regulation have been regularly studied, the role of extracellular phosphate sensing and its impact on fibroblast growth factor 23 (FGF23) expression remains unclear. This study aimed to investigate the involvement of reactive oxygen species (ROS), silent information regulator 1 (SIRT1), and Hairy and Enhancer of Split-1 (HES1) in regulating FGF23 in FGF23 expressing MC3T3-E1 cells. MC3T3-E1 cells treated with β-glycerophosphate (BGP) resulted in increased Fgf23 expression. Inhibition of ROS formation by inhibition of NADPH oxidase, which is essential for ROS production, did not affect this response to BGP, suggesting ROS is not involved in this process. Moreover, treatment with tert-butyl hydroperoxide (TBHP), a ROS-inducing agent, did not increase Fgf23 expression. This suggests that ROS machinery is not involved in FGF23 stimulation as previously suggested. Nonetheless, inhibition of SIRT1 using Ex527 eliminated the Fgf23 response to BGP, indicating its involvement in FGF23 regulation after BGP treatment. Indeed, activation of SIRT1 using SRT1720 increased Fgf23 expression. Moreover, transcription factor Hes1 was upregulated by BGP treatment, which was diminished when cells were treated with Ex527 implying it is also regulated through SIRT1. These findings suggest the existence of an upstream SIRT1-HES1 axis in the regulation of FGF23 by phosphate, though we were unable to find a role for ROS in this process. Further research should provide insights into phosphate homeostasis and potential therapeutic targets for phosphate-related disorders.
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Affiliation(s)
- Danielle M A Ratsma
- Laboratory for Calcium and Bone Metabolism and Erasmus MC Bone Centre, Department of Internal Medicine, Erasmus MC, Erasmus University Medical Center, Room Ee585b, Dr. Molewaterplein 40, 3015 GD, Rotterdam, The Netherlands
| | - Max Muller
- Laboratory for Calcium and Bone Metabolism and Erasmus MC Bone Centre, Department of Internal Medicine, Erasmus MC, Erasmus University Medical Center, Room Ee585b, Dr. Molewaterplein 40, 3015 GD, Rotterdam, The Netherlands
| | - Marijke Koedam
- Laboratory for Calcium and Bone Metabolism and Erasmus MC Bone Centre, Department of Internal Medicine, Erasmus MC, Erasmus University Medical Center, Room Ee585b, Dr. Molewaterplein 40, 3015 GD, Rotterdam, The Netherlands
| | - M Carola Zillikens
- Laboratory for Calcium and Bone Metabolism and Erasmus MC Bone Centre, Department of Internal Medicine, Erasmus MC, Erasmus University Medical Center, Room Ee585b, Dr. Molewaterplein 40, 3015 GD, Rotterdam, The Netherlands
| | - Bram C J van der Eerden
- Laboratory for Calcium and Bone Metabolism and Erasmus MC Bone Centre, Department of Internal Medicine, Erasmus MC, Erasmus University Medical Center, Room Ee585b, Dr. Molewaterplein 40, 3015 GD, Rotterdam, The Netherlands.
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3
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Kim JE, Cho MH. Effects of Multiwall Carbon Nanotubes on Premature Kidney Aging: Biochemical and Histological Analysis. TOXICS 2023; 11:373. [PMID: 37112600 PMCID: PMC10143039 DOI: 10.3390/toxics11040373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 04/01/2023] [Accepted: 04/11/2023] [Indexed: 06/19/2023]
Abstract
Carbon nanotubes (CNTs) have gained much attention due to their superb properties, which make them promising options for the reinforcing composite materials with desirable mechanical properties. However, little is known about the linkage between lung exposure to nanomaterials and kidney disease. In this study, we compared the effects on the kidneys and aging for two different types of multiwall carbon nanotubes (MWCNTs): pristine MWCNTs (PMWCNTs) and acid-treated MWCNTs (TMWCNTs), with TMWCNTs being the preferred form for use as a composite material due to its superior dispersion properties. We used tracheal instillation and maximum tolerated dose (MTD) for both types of CNTs. MTD was determined as a 10% weight loss dose in a 3-month subchronic study, and the appropriate dosage for 1-year exposure was 0.1 mg/mouse. Serum and kidney samples were analyzed using ELISA, Western blot, and immunohistochemistry after 6 months and 1 year of treatment. PMWCNT-administered mice showed the activation of pathways for inflammation, apoptosis, and insufficient autophagy, as well as decreased serum Klotho levels and increased serum levels of DKK-1, FGF-23, and sclerostin, while TMWCNTs did not. Our study suggests that lung exposure to PMWCNTs can induce premature kidney aging and highlights a possible toxic effect of using MWCNTs on the kidneys in the industrial field, further highlighting that dispersibility can affect the toxicity of the nanotubes.
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Affiliation(s)
- Ji-Eun Kim
- Laboratory of Toxicology, College of Veterinary Medicine, Seoul National University, Seoul 151-742, Republic of Korea
- Program in Developmental & Stem Cell Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Myung-Haing Cho
- Laboratory of Toxicology, College of Veterinary Medicine, Seoul National University, Seoul 151-742, Republic of Korea
- RNABIO, Seongnam 13201, Republic of Korea
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4
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Shiels P, Tran N, McCavitt J, Neytchev O, Stenvinkel P. Chronic Kidney Disease and the Exposome of Ageing. Subcell Biochem 2023; 103:79-94. [PMID: 37120465 DOI: 10.1007/978-3-031-26576-1_5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2023]
Abstract
The gap between improvements in lifespan and age-related health is widening. Globally, the demographic of ageing is increasing and there has emerged a 'diseasome of ageing', typified by a range of non-communicable diseases which share a common underlying component of a dysregulated ageing process. Within this, chronic kidney disease is an emerging global epidemic.The extensive inter-individual variation displayed in how people age and how their diseasome manifests and progresses, has required a renewed focus on their life course exposures and the interplay between the environment and the (epi)genome. Termed the exposome, life course abiotic and biotic factors have a significant impact on renal health.We explore how the exposome of renal ageing can predispose and affect CKD progression. We discuss how the kidney can be used as a model to understand the impact of the exposome in health and chronic kidney disease and how this might be manipulated to improve health span.Notably, we discuss the manipulation of the foodome to mitigate acceleration of ageing processes by phosphate and to explore use of emerging senotherapies. A range of senotherapies, for removing senescent cells, diminishing inflammatory burden and either directly targeting Nrf2, or manipulating it indirectly via modification of the microbiome are discussed.
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Affiliation(s)
- Paul Shiels
- SoMBS, Davidson Building, University of Glasgow, Glasgow, UK.
| | - Ngoc Tran
- SoMBS, Davidson Building, University of Glasgow, Glasgow, UK
| | - Jen McCavitt
- SoMBS, Davidson Building, University of Glasgow, Glasgow, UK
| | - Ognian Neytchev
- SoMBS, Davidson Building, University of Glasgow, Glasgow, UK
| | - Peter Stenvinkel
- Division of Renal Medicine, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden
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5
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Cardiac Calcifications: Phenotypes, Mechanisms, Clinical and Prognostic Implications. BIOLOGY 2022; 11:biology11030414. [PMID: 35336788 PMCID: PMC8945469 DOI: 10.3390/biology11030414] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 02/21/2022] [Accepted: 03/07/2022] [Indexed: 12/20/2022]
Abstract
There is a growing interest in arterial and heart valve calcifications, as these contribute to cardiovascular outcome, and are leading predictors of cardiovascular and kidney diseases. Cardiovascular calcifications are often considered as one disease, but, in effect, they represent multifaced disorders, occurring in different milieus and biological phenotypes, following different pathways. Herein, we explore each different molecular process, its relative link with the specific clinical condition, and the current therapeutic approaches to counteract calcifications. Thus, first, we explore the peculiarities between vascular and valvular calcium deposition, as this occurs in different tissues, responds differently to shear stress, has specific etiology and time courses to calcification. Then, we differentiate the mechanisms and pathways leading to hyperphosphatemic calcification, typical of the media layer of the vessel and mainly related to chronic kidney diseases, to those of inflammation, typical of the intima vascular calcification, which predominantly occur in atherosclerotic vascular diseases. Finally, we examine calcifications secondary to rheumatic valve disease or other bacterial lesions and those occurring in autoimmune diseases. The underlying clinical conditions of each of the biological calcification phenotypes and the specific opportunities of therapeutic intervention are also considered and discussed.
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6
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Zhao M, Murakami S, Matsumaru D, Kawauchi T, Nabeshima YI, Motohashi H. NRF2 Pathway Activation Attenuates Aging-Related Renal Phenotypes due to α-Klotho Deficiency. J Biochem 2022; 171:579-589. [DOI: 10.1093/jb/mvac014] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Accepted: 02/03/2022] [Indexed: 11/13/2022] Open
Abstract
Summary
Oxidative stress is one of the major causes of the age-related functional decline in cells and tissues. The KEAP1-NRF2 system plays a central role in the regulation of redox balance, and NRF2 activation exerts antiaging effects by controlling oxidative stress in aged tissues. α-Klotho was identified as an aging suppressor protein based on the premature aging phenotypes of its mutant mice, and its expression is known to gradually decrease during aging. Because α-Klotho has been shown to possess antioxidant function, aging-related phenotypes of α-Klotho mutant mice seem to be attributable to increased oxidative stress at least in part. To examine whether NRF2 activation antagonizes aging-related phenotypes caused by α-Klotho deficiency, we crossed α-Klotho-deficient (Kl–/–) mice with a Keap1-knockdown background, in which the NRF2 pathway is constitutively activated in the whole body. NRF2 pathway activation in Kl–/– mice extended the lifespan and dramatically improved aging-related renal phenotypes. With elevated expression of antioxidant genes accompanied by an oxidative stress decrease, the antioxidant effects of NRF2 seem to make a major contribution to the attenuation of aging-related renal phenotypes of Kl–/– mice. Thus, NRF2 is expected to exert an antiaging function by partly compensating for the functional decline of α-Klotho during physiological aging.
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Affiliation(s)
- Mingyue Zhao
- Department of Gene Expression Regulation, Institute of Development, Aging and Cancer, Tohoku University, Sendai, 980-8575, Japan
| | - Shohei Murakami
- Department of Gene Expression Regulation, Institute of Development, Aging and Cancer, Tohoku University, Sendai, 980-8575, Japan
| | - Daisuke Matsumaru
- Department of Gene Expression Regulation, Institute of Development, Aging and Cancer, Tohoku University, Sendai, 980-8575, Japan
| | - Takeshi Kawauchi
- Laboratory of Molecular Life Science, Institute of Biomedical Research and Innovation, Foundation for Biomedical Research and Innovation at Kobe, Kobe 650-0047, Japan
| | - Yo-ichi Nabeshima
- Laboratory of Molecular Life Science, Institute of Biomedical Research and Innovation, Foundation for Biomedical Research and Innovation at Kobe, Kobe 650-0047, Japan
| | - Hozumi Motohashi
- Department of Gene Expression Regulation, Institute of Development, Aging and Cancer, Tohoku University, Sendai, 980-8575, Japan
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7
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Razzaque MS. Salivary phosphate as a biomarker for human diseases. FASEB Bioadv 2022; 4:102-108. [PMID: 35141474 PMCID: PMC8814558 DOI: 10.1096/fba.2021-00104] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 10/26/2021] [Accepted: 10/27/2021] [Indexed: 12/20/2022] Open
Abstract
Phosphate is a common ingredient of the daily consumed foods and is absorbed in the intestine and is excreted in the urine through the kidney to maintain the homeostatic balance. For adults, the Recommended Dietary Allowance (RDA) for phosphorus is around 700 mg/day. The change in dietary habits resulted in far more phosphate consumption (almost double) than the RDA, contributing to increased cardiovascular diseases, kidney diseases, and tumor formation. Due to a lack of clinical appreciation for the long-term consequences of chronic phosphate burden on non-communicable disorders, it is rapidly becoming a global health concern. The possible association between dysregulated phosphate metabolism and obesity is not studied in-depth, mainly because such an association is believed to be nonexistent. However, in the animal model of obesity, serum phosphate level was higher than their non-obese controls. In a similar observation line, significantly higher salivary phosphate levels were detected in obese children compared to normal-weight children. Of clinical importance, despite the significant increase of salivary phosphate levels in obese children, the plasma phosphate levels did not change in samples collected from the same group of children. Such disparity between plasma and saliva raised the possibility that human salivary phosphate levels may be an early biomarker of childhood obesity.
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Affiliation(s)
- Mohammed S. Razzaque
- Department of PathologyLake Erie College of Osteopathic MedicineEriePennsylvaniaUSA
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8
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Common Dietary Sources of Natural and Artificial Phosphate in Food. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1362:99-105. [DOI: 10.1007/978-3-030-91623-7_10] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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9
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Vitamin D and Phosphate Interactions in Health and Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1362:37-46. [DOI: 10.1007/978-3-030-91623-7_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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10
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Phosphate Burden and Inflammation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1362:7-13. [DOI: 10.1007/978-3-030-91623-7_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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11
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Phosphate Metabolism: From Physiology to Toxicity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1362:1-6. [DOI: 10.1007/978-3-030-91623-7_1] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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12
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Michigami T, Yamazaki M, Razzaque MS. Extracellular Phosphate, Inflammation and Cytotoxicity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1362:15-25. [DOI: 10.1007/978-3-030-91623-7_3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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13
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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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Stone-Weiss N, Bradtmüller H, Eckert H, Goel A. Composition-Structure-Solubility Relationships in Borosilicate Glasses: Toward a Rational Design of Bioactive Glasses with Controlled Dissolution Behavior. ACS APPLIED MATERIALS & INTERFACES 2021; 13:31495-31513. [PMID: 34219455 DOI: 10.1021/acsami.1c07519] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Owing to their fast but tunable degradation kinetics (in comparison to silicates) and excellent bioactivity, the past decade has witnessed an upsurge in the research interest of borate/borosilicate-based bioactive glasses for their potential use in a wide range of soft tissue regeneration applications. Nevertheless, most of these glasses have been developed using trial-and-error approaches wherein SiO2 has been gradually replaced by B2O3. One major reason for using this empirical approach is the complexity of short-to-intermediate range structures of these glasses which greatly complicate the development of a thorough understanding of composition-structure-solubility relationships in these systems. Transitioning beyond the current style of composition design to a style that facilitates the development of bioactive glasses with controlled ion release tailored for specific patients/diseases requires a deeper understanding of the compositional/structural dependence of glass degradation behavior in vitro and in vivo. Accordingly, the present study aims to decipher the structural drivers controlling the dissolution kinetics and ion-release behavior of potentially bioactive glasses designed in the Na2O-B2O3-P2O5-SiO2 system across a broad compositional space in simulated body environments (pH = 7.4). By employing state-of-the-art spectroscopy-based characterization techniques, it has been shown that the degradation kinetics of borosilicate glasses depend on their R (Na2O/B2O3) and K (SiO2/B2O3) ratios, while the release of particular network-forming moieties from the glass into solution is strongly influenced by their role in-and effect on-the short-to-intermediate-range molecular structure. The current study aims to promote a rational design of borosilicate-based bioactive glasses, where a delicate balance between maximizing soft tissue regeneration and minimizing calcification and cytotoxicity can be achieved by tuning the release of ionic dissolution products (of controlled identity and abundance) from bioactive glasses into physiological media.
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Affiliation(s)
- Nicholas Stone-Weiss
- Department of Materials Science and Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
| | - Henrik Bradtmüller
- Institut für Physikalische Chemie, WWU Münster, Corrensstrasse 30, Münster D48149, Germany
- Department of Materials Engineering, Federal University of São Carlos, CP 676, São Carlos, São Paulo 13565-905, Brazil
| | - Hellmut Eckert
- Institut für Physikalische Chemie, WWU Münster, Corrensstrasse 30, Münster D48149, Germany
- São Carlos Institute of Physics, University of São Paulo, Avenida Trabalhador Saocarlense 400, São Carlos, São Paulo 13566-590, Brazil
| | - Ashutosh Goel
- Department of Materials Science and Engineering, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, United States
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Stockman J, Villaverde C. Concerns related to dietary phosphorus intake in cats. J Am Vet Med Assoc 2021; 258:1325-1331. [PMID: 34061616 DOI: 10.2460/javma.258.12.1325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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16
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Kim HS, Jang DY, Koo YJ, Pack EC, Lee SH, Choi DW. Safety assessment of condensed phosphate intake from fishery and processed marine food products in Korea with respect to gender, age, and region. FOOD QUALITY AND SAFETY 2021. [DOI: 10.1093/fqsafe/fyab003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
Condensed phosphates are used as food additives, especially in marine products and meat, to improve food quality. The import and consumption of fishery and processed marine food products in Republic of Korea have reportedly increased by ~5 per cent annually. However, processed marine food products are often intentionally adulterated with excessive amounts of condensed phosphates to increase their weight. Excessive intake of condensed phosphates via consuming processed marine food products can lead to various adverse effects on human health due to anionic imbalance. Herein, we conducted a safety assessment of condensed phosphates in 14 types of fishery and processed marine food products in Korea for the first time. Subgroup analysis of various factors including gender, age, and region was also performed, and the risk level of exposure for each group was estimated. Safety assessments by age and gender indicated that infants were at the highest risk. In the regional safety assessment, Chungnam, the most inland region, showed the lowest risk. For both the general and the high-intake groups (95th percentile) in all classifications, the risk was lower (<20 per cent) than the international standard, and the phosphorus content of the 14 types of processed marine products in Korea was confirmed to be safe for human consumption.
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Affiliation(s)
- Hyung Soo Kim
- Health Science Research Center, Korea University, Seoul, Republic of Korea
| | - Dae Yong Jang
- Department of Public Health Sciences, Graduate School, Korea University, Seoul, Republic of Korea
| | - Ye Ji Koo
- Department of Public Health Sciences, Graduate School, Korea University, Seoul, Republic of Korea
| | - Eun Chul Pack
- School of Health and Environmental Sciences, Korea University, Seoul, Republic of Korea
| | - Seung Ha Lee
- Health Science Research Center, Korea University, Seoul, Republic of Korea
| | - Dal Woong Choi
- Department of Health and Safety Convergence Science, Graduate School, Korea University, Seoul, Republic of Korea
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Hanazaki A, Ikuta K, Sasaki S, Sasaki S, Koike M, Tanifuji K, Arima Y, Kaneko I, Shiozaki Y, Tatsumi S, Hasegawa T, Amizuka N, Miyamoto K, Segawa H. Role of sodium-dependent Pi transporter/Npt2c on Pi homeostasis in klotho knockout mice different properties between juvenile and adult stages. Physiol Rep 2020; 8:e14324. [PMID: 32026654 PMCID: PMC7002534 DOI: 10.14814/phy2.14324] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
SLC34A3/NPT2c/NaPi-2c/Npt2c is a growth-related NaPi cotransporter that mediates the uptake of renal sodium-dependent phosphate (Pi). Mutation of human NPT2c causes hereditary hypophosphatemic rickets with hypercalciuria. Mice with Npt2c knockout, however, exhibit normal Pi metabolism. To investigate the role of Npt2c in Pi homeostasis, we generated α-klotho-/- /Npt2c-/- (KL2cDKO) mice and analyzed Pi homeostasis. α-Klotho-/- (KLKO) mice exhibit hyperphosphatemia and markedly increased kidney Npt2c protein levels. Genetic disruption of Npt2c extended the lifespan of KLKO mice similar to that of α-Klotho-/- /Npt2a-/- mice. Adult KL2cDKO mice had hyperphosphatemia, but analysis of Pi metabolism revealed significantly decreased intestinal and renal Pi (re)absorption compared with KLKO mice. The 1,25-dihydroxy vitamin D3 concentration was not reduced in KL2cDKO mice compared with that in KLKO mice. The KL2cDKO mice had less severe soft tissue and vascular calcification compared with KLKO mice. Juvenile KL2cDKO mice had significantly reduced plasma Pi levels, but Pi metabolism was not changed. In Npt2cKO mice, plasma Pi levels began to decrease around the age of 15 days and significant hypophosphatemia developed within 21 days. The findings of the present study suggest that Npt2c contributes to regulating plasma Pi levels in the juvenile stage and affects Pi retention in the soft and vascular tissues in KLKO mice.
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Affiliation(s)
- Ai Hanazaki
- Department of Applied NutritionInstitute of Biomedical SciencesTokushima University Graduate School TokushimaTokushimaJapan
| | - Kayo Ikuta
- Department of Applied NutritionInstitute of Biomedical SciencesTokushima University Graduate School TokushimaTokushimaJapan
| | - Shohei Sasaki
- Department of Applied NutritionInstitute of Biomedical SciencesTokushima University Graduate School TokushimaTokushimaJapan
| | - Sumire Sasaki
- Department of Applied NutritionInstitute of Biomedical SciencesTokushima University Graduate School TokushimaTokushimaJapan
| | - Megumi Koike
- Department of Applied NutritionInstitute of Biomedical SciencesTokushima University Graduate School TokushimaTokushimaJapan
| | - Kazuya Tanifuji
- Department of Applied NutritionInstitute of Biomedical SciencesTokushima University Graduate School TokushimaTokushimaJapan
| | - Yuki Arima
- Department of Applied NutritionInstitute of Biomedical SciencesTokushima University Graduate School TokushimaTokushimaJapan
| | - Ichiro Kaneko
- Department of Applied NutritionInstitute of Biomedical SciencesTokushima University Graduate School TokushimaTokushimaJapan
| | - Yuji Shiozaki
- Department of Applied NutritionInstitute of Biomedical SciencesTokushima University Graduate School TokushimaTokushimaJapan
| | - Sawako Tatsumi
- Department of Applied NutritionInstitute of Biomedical SciencesTokushima University Graduate School TokushimaTokushimaJapan
| | - Tomoka Hasegawa
- Developmental Biology of Hard TissueHokkaido University Graduate School of Dental MedicineSapporoJapan
| | - Norio Amizuka
- Developmental Biology of Hard TissueHokkaido University Graduate School of Dental MedicineSapporoJapan
| | - Ken‐ichi Miyamoto
- Department of Applied NutritionInstitute of Biomedical SciencesTokushima University Graduate School TokushimaTokushimaJapan
| | - Hiroko Segawa
- Department of Applied NutritionInstitute of Biomedical SciencesTokushima University Graduate School TokushimaTokushimaJapan
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18
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Shi M, Maique J, Shaffer J, Davidson T, Sebti S, Fernández ÁF, Zou Z, Yan S, Levine B, Moe OW, Hu MC. The tripartite interaction of phosphate, autophagy, and αKlotho in health maintenance. FASEB J 2020; 34:3129-3150. [PMID: 31908069 PMCID: PMC7286356 DOI: 10.1096/fj.201902127r] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 12/19/2019] [Accepted: 12/19/2019] [Indexed: 12/11/2022]
Abstract
Aging-related organ degeneration is driven by multiple factors including the cell maintenance mechanisms of autophagy, the cytoprotective protein αKlotho, and the lesser known effects of excess phosphate (Pi), or phosphotoxicity. To examine the interplay between Pi, autophagy, and αKlotho, we used the BK/BK mouse (homozygous for mutant Becn1F121A ) with increased autophagic flux, and αKlotho-hypomorphic mouse (kl/kl) with impaired urinary Pi excretion, low autophagy, and premature organ dysfunction. BK/BK mice live longer than WT littermates, and have heightened phosphaturia from downregulation of two key NaPi cotransporters in the kidney. The multi-organ failure in kl/kl mice was rescued in the double-mutant BK/BK;kl/kl mice exhibiting lower plasma Pi, improved weight gain, restored plasma and renal αKlotho levels, decreased pathology of multiple organs, and improved fertility compared to kl/kl mice. The beneficial effects of heightened autophagy from Becn1F121A was abolished by chronic high-Pi diet which also shortened life span in the BK/BK;kl/kl mice. Pi promoted beclin 1 binding to its negative regulator BCL2, which impairs autophagy flux. Pi downregulated αKlotho, which also independently impaired autophagy. In conclusion, Pi, αKlotho, and autophagy interact intricately to affect each other. Both autophagy and αKlotho antagonizes phosphotoxicity. In concert, this tripartite system jointly determines longevity and life span.
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Affiliation(s)
- Mingjun Shi
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Jenny Maique
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Joy Shaffer
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Taylor Davidson
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Salwa Sebti
- Center for Autophagy Research, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Álvaro F. Fernández
- Center for Autophagy Research, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Zhongju Zou
- Center for Autophagy Research, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Shirley Yan
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Beth Levine
- Center for Autophagy 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 Microbiology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Howard Hughes Medical Institute, 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
| | - 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
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19
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Abstract
The Klotho proteins, αKlotho and βKlotho, are essential components of endocrine fibroblast growth factor (FGF) receptor complexes, as they are required for the high-affinity binding of FGF19, FGF21 and FGF23 to their cognate FGF receptors (FGFRs). Collectively, these proteins form a unique endocrine system that governs multiple metabolic processes in mammals. FGF19 is a satiety hormone that is secreted from the intestine on ingestion of food and binds the βKlotho-FGFR4 complex in hepatocytes to promote metabolic responses to feeding. By contrast, under fasting conditions, the liver secretes the starvation hormone FGF21, which induces metabolic responses to fasting and stress responses through the activation of the hypothalamus-pituitary-adrenal axis and the sympathetic nervous system following binding to the βKlotho-FGFR1c complex in adipocytes and the suprachiasmatic nucleus, respectively. Finally, FGF23 is secreted by osteocytes in response to phosphate intake and binds to αKlotho-FGFR complexes, which are expressed most abundantly in renal tubules, to regulate mineral metabolism. Growing evidence suggests that the FGF-Klotho endocrine system also has a crucial role in the pathophysiology of ageing-related disorders, including diabetes, cancer, arteriosclerosis and chronic kidney disease. Therefore, targeting the FGF-Klotho endocrine axes might have therapeutic benefit in multiple systems; investigation of the crystal structures of FGF-Klotho-FGFR complexes is paving the way for the development of drugs that can regulate these axes.
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Affiliation(s)
- Makoto Kuro-O
- Division of Anti-aging Medicine, Center for Molecular Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan. .,Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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Mencke R, Umbach AT, Wiggenhauser LM, Voelkl J, Olauson H, Harms G, Bulthuis M, Krenning G, Quintanilla-Martinez L, van Goor H, Lang F, Hillebrands JL. Klotho Deficiency Induces Arteriolar Hyalinosis in a Trade-Off with Vascular Calcification. THE AMERICAN JOURNAL OF PATHOLOGY 2019; 189:2503-2515. [DOI: 10.1016/j.ajpath.2019.08.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 08/11/2019] [Accepted: 08/19/2019] [Indexed: 02/07/2023]
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21
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Shim S, Won S, Reza A, Kim S, Ahn S, Jung B, Yoon B, Ra C. In Vivo Toxicity and In Vitro Solubility Assessment of Pre-Treated Struvite as A Potential Alternative Phosphorus Source in Animal Feed. Animals (Basel) 2019; 9:ani9100785. [PMID: 31614549 PMCID: PMC6826386 DOI: 10.3390/ani9100785] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 10/07/2019] [Accepted: 10/07/2019] [Indexed: 12/29/2022] Open
Abstract
Apart from using as fertilizer for plants, the application of struvite may be expanded to animal feed industries through proper pre-treatment. This study aimed to investigate the safety and efficacy of using pre-treated struvite (microwave irradiated struvite (MS) and incinerated struvite (IS)) in animal feeds. For safety assessment, an in vivo toxicity experiment using thirty female Sprague Dawley rats (average body weight (BW) of 200 ± 10 g) was conducted. The rats were randomly divided into five groups, including a control. Based on the BW, MS and IS were applied daily by oral administration with 1 and 10 mg kg-1-BW (MS1 and MS10; IS1 and IS10) using dimethyl sulfoxide (DMSO) as a vehicle. A series of jar tests were conducted for four hours to check the solubility of the MS and IS at different pH (pH 2, 4, and 5) and compared to a commercial P source (monocalcium phosphate, MCP, control). The toxicity experiment results showed no significant differences among the treatments in BW and organ (liver, kidney, heart, and lung) weight of rats (p > 0.05). There were no adverse effects on blood parameters and the histopathological examination showed no inflammation in the organ tissues in MS and IS treated groups compared to the control. In an in vitro solubility test, no significant difference was observed in ortho-phosphate (O-P) solubility from the MCP and MS at pH 2 and 4 (p > 0.05), while O-P solubility from MS at pH 5 to 7 was higher than MCP and found to be significantly different (p < 0.05). O-P solubility from IS was the lowest among the treatments and significantly different from MCP and MS in all the experiments (p < 0.05). The results of this study not only suggest that the struvite pre-treated as MS could be a potential alternative source of P in animal feed but also motivate further studies with more stringent designs to better examine the potential of struvite application in diverse fields.
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Affiliation(s)
- Soomin Shim
- Department of Animal Industry Convergence, College of Animal Life Sciences, Kangwon National University, Chuncheon 24341, Korea.
| | - Seunggun Won
- Department of Animal Resources, College of Life and Environmental Science, Daegu University, Gyeongsan 38453, Korea.
| | - Arif Reza
- Department of Animal Industry Convergence, College of Animal Life Sciences, Kangwon National University, Chuncheon 24341, Korea.
- Department of Environmental Science, College of Agricultural Sciences, IUBAT-International University of Business Agriculture and Technology, Dhaka 1230, Bangladesh.
| | - Seungsoo Kim
- Department of Animal Industry Convergence, College of Animal Life Sciences, Kangwon National University, Chuncheon 24341, Korea.
| | - Sungil Ahn
- Department of Animal Industry Convergence, College of Animal Life Sciences, Kangwon National University, Chuncheon 24341, Korea.
| | - Baedong Jung
- Department of Veterinary Science, Kangwon National University, Chuncheon 24341, Korea.
| | - Byungil Yoon
- Department of Veterinary Science, Kangwon National University, Chuncheon 24341, Korea.
| | - Changsix Ra
- Department of Animal Industry Convergence, College of Animal Life Sciences, Kangwon National University, Chuncheon 24341, Korea.
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22
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Vervloet M. Modifying Phosphate Toxicity in Chronic Kidney Disease. Toxins (Basel) 2019; 11:E522. [PMID: 31505780 PMCID: PMC6784221 DOI: 10.3390/toxins11090522] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Revised: 08/29/2019] [Accepted: 09/05/2019] [Indexed: 02/06/2023] Open
Abstract
Phosphate toxicity is a well-established phenomenon, especially in chronic kidney disease (CKD), where hyperphosphatemia is a frequent occurrence when CKD is advanced. Many therapeutic efforts are targeted at phosphate, and comprise dietary intervention, modifying dialysis schemes, treating uncontrolled hyperparathyroidism and importantly, phosphate binder therapy. Despite all these interventions, hyperphosphatemia persists in many, and its pathological influence is ongoing. In nephrological care, a somewhat neglected aspect of treatment-when attempts fail to lower exposure to a toxin like phosphate-is to explore the possibility of "anti-dotes". Indeed, quite a long list of factors modify, or are mediators of phosphate toxicity. Addressing these, especially when phosphate itself cannot be sufficiently controlled, may provide additional protection. In this narrative overview, several factors are discussed that may qualify as either such a modifier or mediator, that can be influenced by other means than simply lowering phosphate exposure. A wider scope when targeting phosphate-induced comorbidity in CKD, in particular cardiovascular disease, may alleviate the burden of disease that is the consequence of this potentially toxic mineral in CKD.
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Affiliation(s)
- Marc Vervloet
- Department of Nephrology and Amsterdam Cardiovascular Sciences, Amsterdam University Medical Center, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands.
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23
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Shimada M, Shutto-Uchita Y, Yamabe H. Lack of Awareness of Dietary Sources of Phosphorus Is a Clinical Concern. In Vivo 2019; 33:11-16. [PMID: 30587596 PMCID: PMC6364062 DOI: 10.21873/invivo.11432] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 10/23/2018] [Accepted: 10/24/2018] [Indexed: 01/04/2023]
Abstract
Hyperphosphatemia is a serious complication in patients with chronic kidney disease (CKD), and is associated with more rapid progression as well as higher risk of mortality, and higher rate of cardiovascular disease accidents. CKD patients are usually advised to adopt a low phosphate diet in addition to phosphate-lowering medications, if necessary. However, there is a lack of awareness of the dietary sources of phosphate, especially hidden phosphate intake from phosphate additives in processed foods and carbonated beverages. Appropriate nutritional education could be an effective solution in reducing phosphate toxicity without introducing an additional pill burden or malnutrition.
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Affiliation(s)
- Michiko Shimada
- Department of Cardiology and Nephrology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
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24
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Erem S, Razzaque MS. Dietary phosphate toxicity: an emerging global health concern. Histochem Cell Biol 2018; 150:711-719. [PMID: 30159784 DOI: 10.1007/s00418-018-1711-8] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/17/2018] [Indexed: 12/27/2022]
Abstract
Phosphate is a common ingredient in many healthy foods but, it is also present in foods containing additives and preservatives. When found in foods, phosphate is absorbed in the intestines and filtered from the blood by the kidneys. Generally, any excess is excreted in the urine. In renal pathologies, however, such as chronic kidney disease, a reduced renal ability to excrete phosphate can result in excess accumulation in the body. This accumulation can be a catalyst for widespread damage to the cellular components, bones, and cardiovascular structures. This in turn can reduce mortality. Because of an incomplete understanding of the mechanism for phosphate homeostasis, and the multiple organ systems that can modulate it, treatment strategies designed to minimize phosphate burden are limited. The Recommended Dietary Allowance (RDA) for phosphorous is around 700 mg/day for adults, but the majority of healthy adult individuals consume far more phosphate (almost double) than the RDA. Studies suggest that low-income populations are particularly at risk for dietary phosphate overload because of the higher amounts of phosphate found in inexpensive, processed foods. Education in nutrition, as well as access to inexpensive healthy food options may reduce risks for excess consumption as well as a wide-range of disorders, ranging from cardiovascular diseases to kidney diseases to tumor formation. Pre-clinical and clinical studies suggest that dietary phosphate overload has toxic and prolonged adverse health effects. Improved regulations for reporting of phosphate concentrations on food labels are necessary so that people can make more informed choices about their diets and phosphate consumption. This is especially the case given the lack of treatments available to mitigate the short and long-term effects of dietary phosphate overload-related toxicity. Phosphate toxicity is quickly becoming a global health concern. Without measures in place to reduce dietary phosphate intake, the conditions associated with phosphate toxicity will likely to cause untold damage to the wellbeing of individuals around the world.
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Affiliation(s)
- Sarah Erem
- Department of Pathology, Saba University School of Medicine, Saba, Dutch Caribbean, The Netherlands
| | - Mohammed S Razzaque
- Department of Pathology, Saba University School of Medicine, Saba, Dutch Caribbean, The Netherlands.
- Department of Oral Health Policy and Epidemiology, Harvard School of Dental Medicine, Boston, MA, USA.
- Department of Preventive and Community Dentistry, School of Dentistry, University of Rwanda College of Medicine & Health Sciences, Kigali, Rwanda.
- Department of Pathology, Lake Erie College of Osteopathic Medicine, 1858 West Grandview Boulevard, Room: B2-306, Erie, PA, 16509, USA.
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25
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Boisvert NC, Holterman CE, Gutsol A, Coulombe J, Pan W, Alexander RT, Gray DA, Kennedy CR. Ubiquitin COOH-terminal hydrolase L1 deletion is associated with urinary α-klotho deficiency and perturbed phosphate homeostasis. Am J Physiol Renal Physiol 2018; 315:F353-F363. [DOI: 10.1152/ajprenal.00411.2017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Loss of ubiquitin COOH-terminal hydrolase L1 (UCHL1), a deubiquitinating enzyme required for neuronal function, led to hyperphosphatemia accompanied by phosphaturia in mice, while calcium homeostasis remained intact. We therefore investigated the mechanisms underlying the phosphate imbalance in Uchl1−/− mice. Interestingly, phosphaturia was not a result of lower renal brush border membrane sodium-phosphate cotransporter expression as sodium-phosphate cotransporter 2a and 2c expression levels was similar to wild-type levels. Plasma parathyroid hormone and fibroblast growth factor 23 levels were not different; however, fibroblast growth factor 23 mRNA levels were significantly increased in femur homogenates from Uchl1−/− mice. Full-length and soluble α-klotho levels were comparable in kidneys from wild-type and Uchl1−/− mice; however, soluble α-klotho was reduced in Uchl1−/− mice urine. Consistent with unchanged components of 1,25(OH)2D3 metabolism (i.e., CYP27B1 and CYP24A1), sodium-phosphate cotransporter 2b protein levels were not different in ileum brush borders from Uchl1−/− mice, suggesting that the intestine is not the source of hyperphosphatemia. Nonetheless, when Uchl1−/− mice were fed a low-phosphate diet, plasma phosphate, urinary phosphate, and fractional excretion of phosphate were significantly attenuated and comparable to levels of low-phosphate diet-fed wild-type mice. Our findings demonstrate that Uchl1-deleted mice exhibit perturbed phosphate homeostasis, likely consequent to decreased urinary soluble α-klotho, which can be rescued with a low-phosphate diet. Uchl1−/− mice may provide a useful mouse model to study mild perturbations in phosphate homeostasis.
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Affiliation(s)
- Naomi C. Boisvert
- Kidney Research Centre, The Ottawa Hospital, Ottawa, Ontario, Canada
- Ottawa Hospital Research Institute, The Ottawa Hospital, Ottawa, Ontario, Canada
- Faculty of Medicine, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Chet E. Holterman
- Kidney Research Centre, The Ottawa Hospital, Ottawa, Ontario, Canada
- Ottawa Hospital Research Institute, The Ottawa Hospital, Ottawa, Ontario, Canada
| | - Alexey Gutsol
- Kidney Research Centre, The Ottawa Hospital, Ottawa, Ontario, Canada
- Ottawa Hospital Research Institute, The Ottawa Hospital, Ottawa, Ontario, Canada
| | - Josée Coulombe
- Ottawa Hospital Research Institute, The Ottawa Hospital, Ottawa, Ontario, Canada
| | - Wanling Pan
- Department of Physiology, University of Alberta, Edmonton, Alberta, Canada
| | - R. Todd Alexander
- Department of Physiology, University of Alberta, Edmonton, Alberta, Canada
- Membrane Protein Disease Research Group, University of Alberta, Edmonton, Alberta, Canada
- Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada
| | - Douglas A. Gray
- Ottawa Hospital Research Institute, The Ottawa Hospital, Ottawa, Ontario, Canada
- Faculty of Medicine, Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada
| | - Chris R. Kennedy
- Kidney Research Centre, The Ottawa Hospital, Ottawa, Ontario, Canada
- Ottawa Hospital Research Institute, The Ottawa Hospital, Ottawa, Ontario, Canada
- Faculty of Medicine, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
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26
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Filipski KJ, Sammons MF, Bhattacharya SK, Panteleev J, Brown JA, Loria PM, Boehm M, Smith AC, Shavnya A, Conn EL, Song K, Weng Y, Facemire C, Jüppner H, Clerin V. Discovery of Orally Bioavailable Selective Inhibitors of the Sodium-Phosphate Cotransporter NaPi2a (SLC34A1). ACS Med Chem Lett 2018; 9:440-445. [PMID: 29795756 DOI: 10.1021/acsmedchemlett.8b00013] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 04/04/2018] [Indexed: 11/30/2022] Open
Abstract
Sodium-phosphate cotransporter 2a, or NaPi2a (SLC34A1), is a solute-carrier (SLC) transporter located in the kidney proximal tubule that reabsorbs glomerular-filtered phosphate. Inhibition of NaPi2a may enhance urinary phosphate excretion and correct maladaptive mineral and hormonal derangements associated with increased cardiovascular risk in chronic kidney disease-mineral and bone disorder (CKD-MBD). To date, only nonselective NaPi inhibitors have been described. Herein, we detail the discovery of the first series of selective NaPi2a inhibitors, resulting from optimization of a high-throughput screening hit. The oral PK profile of inhibitor PF-06869206 (6f) in rodents allows for the exploration of the pharmacology of selective NaPi2a inhibition.
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Affiliation(s)
- Kevin J. Filipski
- Pfizer Worldwide Research & Development, 1 Portland Street, Cambridge, Massachusetts 02139, United States
| | - Matthew F. Sammons
- Pfizer Worldwide Research & Development, 1 Portland Street, Cambridge, Massachusetts 02139, United States
| | - Samit K. Bhattacharya
- Pfizer Worldwide Research & Development, 1 Portland Street, Cambridge, Massachusetts 02139, United States
| | - Jane Panteleev
- Pfizer Worldwide Research & Development, 558 Eastern Point Road, Groton, Connecticut 06340, United States
| | - Janice A. Brown
- Pfizer Worldwide Research & Development, 558 Eastern Point Road, Groton, Connecticut 06340, United States
| | - Paula M. Loria
- Pfizer Worldwide Research & Development, 558 Eastern Point Road, Groton, Connecticut 06340, United States
| | - Markus Boehm
- Pfizer Worldwide Research & Development, 1 Portland Street, Cambridge, Massachusetts 02139, United States
| | - Aaron C. Smith
- Pfizer Worldwide Research & Development, 558 Eastern Point Road, Groton, Connecticut 06340, United States
| | - Andre Shavnya
- Pfizer Worldwide Research & Development, 558 Eastern Point Road, Groton, Connecticut 06340, United States
| | - Edward L. Conn
- Pfizer Worldwide Research & Development, 558 Eastern Point Road, Groton, Connecticut 06340, United States
| | - Kun Song
- Pfizer Worldwide Research & Development, 1 Portland Street, Cambridge, Massachusetts 02139, United States
| | - Yan Weng
- Pfizer Worldwide Research & Development, 1 Portland Street, Cambridge, Massachusetts 02139, United States
| | - Carie Facemire
- Pfizer Worldwide Research & Development, 1 Portland Street, Cambridge, Massachusetts 02139, United States
| | - Harald Jüppner
- Endocrine Unit and Pediatric Nephrology Unit, Thier 10, Massachusetts General Hospital and Harvard Medical School, 50 Blossom Street, Boston, Massachusetts 02114, United States
| | - Valerie Clerin
- Pfizer Worldwide Research & Development, 1 Portland Street, Cambridge, Massachusetts 02139, United States
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27
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McClelland R, Christensen K, Mohammed S, McGuinness D, Cooney J, Bakshi A, Demou E, MacDonald E, Caslake M, Stenvinkel P, Shiels PG. Accelerated ageing and renal dysfunction links lower socioeconomic status and dietary phosphate intake. Aging (Albany NY) 2017; 8:1135-49. [PMID: 27132985 PMCID: PMC4931858 DOI: 10.18632/aging.100948] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 04/16/2016] [Indexed: 01/13/2023]
Abstract
BACKGROUND We have sought to explore the impact of dietary Pi intake on human age related health in the pSoBid cohort (n=666) to explain the disparity between health and deprivation status in this cohort. As hyperphosphataemia is a driver of accelerated ageing in rodent models of progeria we tested whether variation in Pi levels in man associate with measures of biological ageing and health. RESULTS We observed significant relationships between serum Pi levels and markers of biological age (telomere length (p=0.040) and DNA methylation content (p=0.028), gender and chronological age (p=0.032). When analyses were adjusted for socio-economic status and nutritional factors, associations were observed between accelerated biological ageing (telomere length, genomic methylation content) and dietary derived Pi levels among the most deprived males, directly related to the frequency of red meat consumption. CONCLUSIONS Accelerated ageing is associated with high serum Pi levels and frequency of red meat consumption. Our data provide evidence for a mechanistic link between high intake of Pi and age-related morbidities tied to socio-economic status.
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Affiliation(s)
- Ruth McClelland
- Institute of Cancer Sciences, MVLS, University of Glasgow, Glasgow, UK
| | - Kelly Christensen
- Institute of Cancer Sciences, MVLS, University of Glasgow, Glasgow, UK
| | - Suhaib Mohammed
- Institute of Cancer Sciences, MVLS, University of Glasgow, Glasgow, UK
| | | | | | - Andisheh Bakshi
- Institute of Health and Wellbeing, MVLS, University of Glasgow, Glasgow, UK
| | - Evangelia Demou
- Institute of Health and Wellbeing, MVLS, University of Glasgow, Glasgow, UK
| | - Ewan MacDonald
- Institute of Health and Wellbeing, MVLS, University of Glasgow, Glasgow, UK
| | - Muriel Caslake
- School of Medicine, MVLS, University of Glasgow, Glasgow, UK
| | - Peter Stenvinkel
- Division of Renal Medicine M99, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden
| | - Paul G Shiels
- Institute of Cancer Sciences, MVLS, University of Glasgow, Glasgow, UK
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28
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Sheng Y, Tang L, Kang L, Xiao R. Membrane ion Channels and Receptors in Animal lifespan Modulation. J Cell Physiol 2017; 232:2946-2956. [PMID: 28121014 PMCID: PMC7008462 DOI: 10.1002/jcp.25824] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 01/23/2017] [Accepted: 01/24/2017] [Indexed: 01/01/2023]
Abstract
Acting in the interfaces between environment and membrane compartments, membrane ion channels, and receptors transduce various physical and chemical cues into downstream signaling events. Not surprisingly, these membrane proteins play essential roles in a wide range of cellular processes such as sensory perception, synaptic transmission, cellular growth and development, fate determination, and apoptosis. However, except insulin and insulin-like growth factor receptors, the functions of membrane receptors in animal lifespan modulation have not been well appreciated. On the other hand, although ion channels are popular therapeutic targets for many age-related diseases, their potential roles in aging itself are largely neglected. In this review, we will discuss our current understanding of the conserved functions and mechanisms of membrane ion channels and receptors in the modulation of lifespan across multiple species including Caenorhabditis elegans, Drosophila, mouse, and human.
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Affiliation(s)
- Yi Sheng
- Division of Biology of Aging, Department of Aging and Geriatric Research, Institute on Aging, College of Medicine, University of Florida, Gainesville, Florida
| | - Lanlan Tang
- Division of Biology of Aging, Department of Aging and Geriatric Research, Institute on Aging, College of Medicine, University of Florida, Gainesville, Florida
| | - Lijun Kang
- Department of Neurobiology, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Institute of Neuroscience, Zhejiang University School of Medicine, Hangzhou, China
| | - Rui Xiao
- Division of Biology of Aging, Department of Aging and Geriatric Research, Institute on Aging, College of Medicine, University of Florida, Gainesville, Florida
- Department of Pharmacology and Therapeutics, College of Medicine, University of Florida, Gainesville, Florida
- Center for Smell and Taste, University of Florida, Gainesville, Florida
- Genetics Institute, University of Florida, Gainesville, Florida
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29
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Merhi B, Shireman T, Carpenter MA, Kusek JW, Jacques P, Pfeffer M, Rao M, Foster MC, Kim SJ, Pesavento TE, Smith SR, Kew CE, House AA, Gohh R, Weiner DE, Levey AS, Ix JH, Bostom A. Serum Phosphorus and Risk of Cardiovascular Disease, All-Cause Mortality, or Graft Failure in Kidney Transplant Recipients: An Ancillary Study of the FAVORIT Trial Cohort. Am J Kidney Dis 2017; 70:377-385. [PMID: 28579423 DOI: 10.1053/j.ajkd.2017.04.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Accepted: 04/03/2017] [Indexed: 12/17/2022]
Abstract
BACKGROUND Mild hyperphosphatemia is a putative risk factor for cardiovascular disease [CVD], loss of kidney function, and mortality. Very limited data are available from sizable multicenter kidney transplant recipient (KTR) cohorts assessing the potential relationships between serum phosphorus levels and the development of CVD outcomes, transplant failure, or all-cause mortality. STUDY DESIGN Cohort study. SETTING & PARTICIPANTS The Folic Acid for Vascular Outcome Reduction in Transplantation (FAVORIT) Trial, a large, multicenter, multiethnic, controlled clinical trial that provided definitive evidence that high-dose vitamin B-based lowering of plasma homocysteine levels did not reduce CVD events, transplant failure, or total mortality in stable KTRs. PREDICTOR Serum phosphorus levels were determined in 3,138 FAVORIT trial participants at randomization. RESULTS During a median follow-up of 4.0 years, the cohort had 436 CVD events, 238 transplant failures, and 348 deaths. Proportional hazards modeling revealed that each 1-mg/dL higher serum phosphorus level was not associated with a significant increase in CVD risk (HR, 1.06; 95% CI, 0.92-1.22), but increased transplant failure (HR, 1.36; 95% CI, 1.15-1.62) and total mortality risk associations (HR, 1.21; 95% CI, 1.04-1.40) when adjusted for treatment allocation, traditional CVD risk factors, kidney measures, type of kidney transplant, transplant vintage, and use of calcineurin inhibitors, steroids, or lipid-lowering drugs. These associations were strengthened in models without kidney measures: CVD (HR, 1.14; 95% CI, 1.00-1.31), transplant failure (HR, 1.72; 95% CI, 1.46-2.01), and mortality (HR, 1.34; 95% CI, 1.15-1.54). LIMITATIONS We lacked data for concentrations of parathyroid hormone, fibroblast growth factor 23, or vitamin D metabolites. CONCLUSIONS Serum phosphorus level is marginally associated with CVD and more strongly associated with transplant failure and total mortality in long-term KTRs. A randomized controlled clinical trial in KTRs that assesses the potential impact of phosphorus-lowering therapy on these hard outcomes may be warranted.
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Affiliation(s)
- Basma Merhi
- Division of Hypertension and Kidney Diseases, Department of Medicine, Rhode Island Hospital, Providence, RI
| | - Theresa Shireman
- Center for Gerontology and Healthcare Research, Brown University, Providence, RI
| | - Myra A Carpenter
- Collaborative Studies Coordinating Center, University of North Carolina, Chapel Hill, NC
| | - John W Kusek
- National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, MD
| | - Paul Jacques
- Nutritional Epidemiology Program, USDA Human Nutrition Research Center on Aging, Boston, MA
| | - Marc Pfeffer
- Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, Boston, MA
| | - Madhumathi Rao
- Division of Nephrology, Department of Medicine, Tufts Medical Center, Boston, MA
| | - Meredith C Foster
- Division of Nephrology, Department of Medicine, Tufts Medical Center, Boston, MA
| | - S Joseph Kim
- Division of Nephrology and the Kidney Transplant Program, Toronto General Hospital, Toronto, Ontario, Canada
| | - Todd E Pesavento
- Division of Nephrology, Department of Medicine, Ohio State University, Columbus, OH
| | - Stephen R Smith
- Division of Nephrology, Department of Medicine, Duke University School of Medicine, Durham, NC
| | - Clifton E Kew
- Division of Nephrology, Department of Medicine, University of Alabama-Birmingham, Birmingham, AL
| | - Andrew A House
- Division of Nephrology, Department of Medicine, London Health Sciences Center, London, Ontario, Canada
| | - Reginald Gohh
- Division of Hypertension and Kidney Diseases, Department of Medicine, Rhode Island Hospital, Providence, RI
| | - Daniel E Weiner
- Division of Nephrology, Department of Medicine, Tufts Medical Center, Boston, MA
| | - Andrew S Levey
- Division of Nephrology, Department of Medicine, Tufts Medical Center, Boston, MA
| | - Joachim H Ix
- Division of Nephrology-Hypertension, Department of Medicine, University of California, San Diego, CA
| | - Andrew Bostom
- Division of Hypertension and Kidney Diseases, Department of Medicine, Rhode Island Hospital, Providence, RI.
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Mencke R, Hillebrands JL. The role of the anti-ageing protein Klotho in vascular physiology and pathophysiology. Ageing Res Rev 2017; 35:124-146. [PMID: 27693241 DOI: 10.1016/j.arr.2016.09.001] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 09/23/2016] [Indexed: 02/08/2023]
Abstract
Klotho is an anti-ageing protein that functions in many pathways that govern ageing, like regulation of phosphate homeostasis, insulin signaling, and Wnt signaling. Klotho expression levels and levels in blood decline during ageing. The vascular phenotype of Klotho deficiency features medial calcification, intima hyperplasia, endothelial dysfunction, arterial stiffening, hypertension, and impaired angiogenesis and vasculogenesis, with characteristics similar to aged human arteries. Klotho-deficient phenotypes can be prevented and rescued by Klotho gene expression or protein supplementation. High phosphate levels are likely to be directly pathogenic and are a prerequisite for medial calcification, but more important determinants are pathways that regulate cellular senescence, suggesting that deficiency of Klotho renders cells susceptible to phosphate toxicity. Overexpression of Klotho is shown to ameliorate medial calcification, endothelial dysfunction, and hypertension. Endogenous vascular Klotho expression is a controversial subject and, currently, no compelling evidence exists that supports the existence of vascular membrane-bound Klotho expression, as expressed in kidney. In vitro, Klotho has been shown to decrease oxidative stress and apoptosis in both SMCs and ECs, to reduce SMC calcification, to maintain the contractile SMC phenotype, and to prevent μ-calpain overactivation in ECs. Klotho has many protective effects with regard to the vasculature and constitutes a very promising therapeutic target. The purpose of this review is to explore the etiology of the vascular phenotype of Klotho deficiency and the therapeutic potential of Klotho in vascular disease.
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The FGF23 and Klotho system beyond mineral metabolism. Clin Exp Nephrol 2016; 21:64-69. [PMID: 27838783 DOI: 10.1007/s10157-016-1357-6] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 10/25/2016] [Indexed: 12/22/2022]
Abstract
FGF23 is a bone-derived hormone that acts primarily on the kidney to induce phosphaturia and suppress synthesis of 1,25-dihydroxyvitamin D3. The unique feature of FGF23 is that it requires Klotho as an obligate co-receptor. The FGF23-Klotho system has emerged as an endocrine axis indispensable for maintaining phosphate homeostasis. Mineral and bone disorders associated with chronic kidney disease (CKD-MBD) can be viewed as a series of events triggered by a compensatory response of the FGF23-Klotho system to excess phosphate intake relative to the residual nephron number. Furthermore, the fact that disruption of the FGF23-Klotho system causes phosphate retention and a syndrome resembling aging in mammals has led to the notion that phosphate accelerates aging. The aging-like pathology caused by phosphate, or phosphatopathy, may be unique to the higher organisms having the Klotho gene and provides new insights into the molecular mechanism of aging in humans.
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Abstract
Fibroblast growth factor-23 (FGF23) is a bone-derived hormone known to suppress phosphate reabsorption and vitamin D hormone production in the kidney. Klotho was originally discovered as an anti-aging factor, but the functional role of Klotho is still a controversial issue. Three major functions have been proposed, a hormonal function of soluble Klotho, an enzymatic function as glycosidase, and the function as an obligatory co-receptor for FGF23 signaling. The purpose of this review is to highlight the recent advances in the area of FGF23 and Klotho signaling in the kidney, in the parathyroid gland, in the cardiovascular system, in bone, and in the central nervous system. During recent years, major new functions of FGF23 and Klotho have been discovered in these organ systems. Based on these novel findings, FGF23 has emerged as a pleiotropic endocrine and auto-/paracrine factor influencing not only mineral metabolism but also cardiovascular function.
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Sung KC, Chang Y, Ryu S, Chung HK. High levels of serum vitamin D are associated with a decreased risk of metabolic diseases in both men and women, but an increased risk for coronary artery calcification in Korean men. Cardiovasc Diabetol 2016; 15:112. [PMID: 27519883 PMCID: PMC4983097 DOI: 10.1186/s12933-016-0432-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 08/02/2016] [Indexed: 02/06/2023] Open
Abstract
Background There are conflicting results for relationships between serum vitamin D levels and metabolic diseases. The aim of this study was to investigate whether serum vitamin D levels were associated with various metabolic diseases including insulin resistance (IR), metabolic syndrome (MS), fatty liver (FL), and coronary artery calcification (CAC), along with assessing gender differences for these relationships in Korean adults. Methods A total of 180,918 subjects (98,412 men and 82,506 women) who participated in a comprehensive health examination in the 2012–2013 period at Kangbuk Samsung Hospital, College of Medicine, Sungkyunkwan University were included. Serum vitamin D and metabolic markers were analyzed and CAC was estimated. Subjects were divided according to quartile groups of serum vitamin D. To examine the relationships of serum vitamin D to metabolic diseases and metabolic factors, multivariate logistic analysis was conducted. Results High levels of serum vitamin D was associated with lower ORs for MS, IR and FL both in men and women (all p < 0.05). For men, ORs for CAC were significantly higher in third and the highest quartile groups for serum vitamin D in all the analyzed models (all p < 0.05). However, women showed no significant results between serum vitamin D and CAC. Conclusions High levels of serum vitamin D were associated with lower risk of MS, IR and FL in both Korean men and women, but were associated with higher risk of CAC only in men, and not in women. Electronic supplementary material The online version of this article (doi:10.1186/s12933-016-0432-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ki-Chul Sung
- Division of Cardiology, Department of Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, 110-746, South Korea.
| | - Yoosoo Chang
- Department of Occupational and Environmental Medicine, Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Seungho Ryu
- Department of Occupational and Environmental Medicine, Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Hye-Kyung Chung
- Severance institute for vascular and metabolic research, Yonsei University College of Medicine, Seoul, 120-749, South Korea.
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Ide N, Olauson H, Sato T, Densmore MJ, Wang H, Hanai JI, Larsson TE, Lanske B. In vivo evidence for a limited role of proximal tubular Klotho in renal phosphate handling. Kidney Int 2016; 90:348-362. [DOI: 10.1016/j.kint.2016.04.009] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 03/29/2016] [Accepted: 04/14/2016] [Indexed: 01/11/2023]
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Zoccali C, Torino C, Curatola G, Panuccio V, Tripepi R, Pizzini P, Versace M, Bolignano D, Cutrupi S, Ghiadoni L, Thadhani R, Tripepi G, Mallamaci F. Serum phosphate modifies the vascular response to vitamin D receptor activation in chronic kidney disease (CKD) patients. Nutr Metab Cardiovasc Dis 2016; 26:581-589. [PMID: 27113290 DOI: 10.1016/j.numecd.2016.03.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 03/01/2016] [Accepted: 03/14/2016] [Indexed: 11/21/2022]
Abstract
BACKGROUND AND AIMS Vitamin D receptor activation (VDRA) ameliorates endothelial dysfunction in CKD patients but also increases phosphate and FGF-23, which may attenuate the beneficial effect of VDRA on endothelial function. METHODS AND RESULTS This is a pre-specified secondary analysis of the PENNY trial (NCT01680198) testing the effect of phosphate and FGF-23 on the flow mediated vasodilatory (FMD) response to paricalcitol (PCT, 2 μg/day) and placebo over a 12-weeks treatment period. Eighty-eight stage G3-4 CKD patients were randomized to PCT (n = 44) and Placebo (n = 44). Endothelial function was assessed by measuring endothelium dependent forearm blood flow (FBF) response to ischemia. The FMD response was by the 61% higher in PCT treated patients than in those on placebo (P = 0.01). Phosphate (+11%, P = 0.039), calcium (+3%, P = 0.01) and, particularly so, FGF23 (+164%, P < 0.001) increased in PCT treated patients. Changes in FMD by PCT associated inversely with phosphate (r = -0.37, P = 0.01) but were independent of FGF-23, calcium and PTH changes. The response to PCT was maximal in patients with no changes in phosphate (1st tertile), attenuated in those with mild-to-moderate rise in phosphate (2nd tertile) and abolished in those with the most pronounced phosphate increase (3rd tertile) (effect modification P = 0.009). No effect modification by FGF-23 and other variables was observed. CONCLUSIONS The beneficial effect of PCT on endothelial function in CKD is maximal in patients with no or minimal changes in phosphate and it is abolished in patients with a pronounced phosphate rise. These findings generate the hypothesis that the endothelium protective effect by VDRA may be potentiated by phosphate lowering interventions.
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Affiliation(s)
- C Zoccali
- CNR-IBIM/IFC Clinical Epidemiology and Pathophysiology of Renal Diseases and Hypertension, Ospedali Riuniti, Reggio Calabria, Italy.
| | - C Torino
- CNR-IBIM/IFC Clinical Epidemiology and Pathophysiology of Renal Diseases and Hypertension, Ospedali Riuniti, Reggio Calabria, Italy
| | - G Curatola
- CNR-IBIM/IFC Clinical Epidemiology and Pathophysiology of Renal Diseases and Hypertension, Ospedali Riuniti, Reggio Calabria, Italy
| | - V Panuccio
- Nephrology, Hypertension and Renal Transplantation Unit, Ospedali Riuniti, Reggio Calabria, Italy
| | - R Tripepi
- CNR-IBIM/IFC Clinical Epidemiology and Pathophysiology of Renal Diseases and Hypertension, Ospedali Riuniti, Reggio Calabria, Italy
| | - P Pizzini
- CNR-IBIM/IFC Clinical Epidemiology and Pathophysiology of Renal Diseases and Hypertension, Ospedali Riuniti, Reggio Calabria, Italy
| | - M Versace
- CNR-IBIM/IFC Clinical Epidemiology and Pathophysiology of Renal Diseases and Hypertension, Ospedali Riuniti, Reggio Calabria, Italy
| | - D Bolignano
- CNR-IBIM/IFC Clinical Epidemiology and Pathophysiology of Renal Diseases and Hypertension, Ospedali Riuniti, Reggio Calabria, Italy
| | - S Cutrupi
- CNR-IBIM/IFC Clinical Epidemiology and Pathophysiology of Renal Diseases and Hypertension, Ospedali Riuniti, Reggio Calabria, Italy
| | - L Ghiadoni
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - R Thadhani
- Department of Medicine, Division of Nephrology, Massachusetts General Hospital, Boston, MA, USA
| | - G Tripepi
- CNR-IBIM/IFC Clinical Epidemiology and Pathophysiology of Renal Diseases and Hypertension, Ospedali Riuniti, Reggio Calabria, Italy
| | - F Mallamaci
- CNR-IBIM/IFC Clinical Epidemiology and Pathophysiology of Renal Diseases and Hypertension, Ospedali Riuniti, Reggio Calabria, Italy; Nephrology, Hypertension and Renal Transplantation Unit, Ospedali Riuniti, Reggio Calabria, Italy
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Komaba H, Fukagawa M. Phosphate-a poison for humans? Kidney Int 2016; 90:753-63. [PMID: 27282935 DOI: 10.1016/j.kint.2016.03.039] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 03/03/2016] [Accepted: 03/24/2016] [Indexed: 02/07/2023]
Abstract
Maintenance of phosphate balance is essential for life, and mammals have developed a sophisticated system to regulate phosphate homeostasis over the course of evolution. However, due to the dependence of phosphate elimination on the kidney, humans with decreased kidney function are likely to be in a positive phosphate balance. Phosphate excess has been well recognized as a critical factor in the pathogenesis of mineral and bone disorders associated with chronic kidney disease, but recent investigations have also uncovered toxic effects of phosphate on the cardiovascular system and the aging process. Compelling evidence also suggests that increased fibroblastic growth factor 23 and parathyroid hormone levels in response to a positive phosphate balance contribute to adverse clinical outcomes. These insights support the current practice of managing serum phosphate in patients with advanced chronic kidney disease, although definitive evidence of these effects is lacking. Given the potential toxicity of excess phosphate, the general population may also be viewed as a target for phosphate management. However, the widespread implementation of dietary phosphate intervention in the general population may not be warranted due to the limited impact of increased phosphate intake on mineral metabolism and clinical outcomes. Nonetheless, the increasing incidence of kidney disease or injury in our aging society emphasizes the potential importance of this issue. Further work is needed to more completely characterize phosphate toxicity and to establish the optimal therapeutic strategy for managing phosphate in patients with chronic kidney disease and in the general population.
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Affiliation(s)
- Hirotaka Komaba
- Division of Nephrology, Endocrinology and Metabolism, Tokai University School of Medicine, Isehara, Japan; Interactive Translational Research Center for Kidney Diseases, Tokai University School of Medicine, Isehara, Japan; The Institute of Medical Sciences, Tokai University, Isehara, Japan
| | - Masafumi Fukagawa
- Division of Nephrology, Endocrinology and Metabolism, Tokai University School of Medicine, Isehara, Japan.
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Brown RB, Haq A, Stanford CF, Razzaque MS. Vitamin D, phosphate, and vasculotoxicity. Can J Physiol Pharmacol 2015; 93:1077-82. [DOI: 10.1139/cjpp-2015-0083] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Vascular calcification is a complex process that results in the ectopic deposition of calcium-phosphate hydroxyapatite. Medial and intimal vascular calcification is frequently present in patients with diabetes mellitus and chronic kidney disease (CKD), and markedly increases the morbidity and mortality of these patients. Increased serum levels of calcium and phosphate, along with the use of active vitamin D metabolites, are commonly implicated in the evolvement of vascular wall mineralization in CKD patients. Because CKD patients have lower serum levels of vitamin D, they are routinely prescribed vitamin D supplements that exert a dualistic role that is both healthful and harmful in these patients, perhaps protecting bone health, but at the expense of promoting vascular pathology. This review briefly explains how reducing the phosphate burden in CKD patients could minimize vitamin-D-associated vascular wall calcification.
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Affiliation(s)
- Ronald B. Brown
- College of Human Ecology, Kansas State University, Manhattan, KS 66506, USA
| | - Afrozul Haq
- Division of Research & Development, VPS Healthcare, Abu Dhabi, UAE
| | | | - Mohammed S. Razzaque
- Division of Research & Development, VPS Healthcare, Abu Dhabi, UAE
- Department of Applied Oral Sciences, Forsyth Institute, 245 First Street, Cambridge, MA 02142, USA
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The Role and Mechanism of α-Klotho in the Calcification of Rat Aortic Vascular Smooth Muscle Cells. BIOMED RESEARCH INTERNATIONAL 2015; 2015:194362. [PMID: 26609522 PMCID: PMC4644825 DOI: 10.1155/2015/194362] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 10/11/2015] [Accepted: 10/19/2015] [Indexed: 11/17/2022]
Abstract
OBJECTIVE To investigate the role and possible mechanism of α-Klotho in the calcification and the osteogenic transition of cultured VSMCs. METHODS VSMCs were cultured in vitro and divided into 5 groups, each using a different medium: (1) control; (2) β-GP; (3) β-GP + Klotho; (4) β-GP + LiCl; (5) β-GP + Klotho + LiCl. Calcium deposits were visualized using Alizarin Red S staining. The calcium concentrations were determined by the o-cresolphthalein complexone method. BMP2, Runx2 and β-catenin levels were estimated by western blotting, and the level of α-SMA was determined by using immunofluorescence at day 12. RESULTS β-GP induced an increase in the expression of BMP2, Runx2, and β-catenin. The calcium content increased, and the expression of α-SMA decreased. Alizarin Red S staining was positive under the high phosphorus conditions. BMP2, Runx2, and β-catenin levels and the calcium content decreased when the cells were cultured with rmKlotho; however, the levels of each were upregulated after treatment with the LiCl. CONCLUSIONS Klotho can ameliorate the calcification and osteogenic transition of VSMCs induced by β-GP. The mechanism of Klotho in preventing calcification in VSMCs may be partially mediated by the inhibition of the Wnt/β-catenin signaling pathway.
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Tatsumoto N, Yamada S, Tokumoto M, Eriguchi M, Noguchi H, Torisu K, Tsuruya K, Kitazono T. Spironolactone ameliorates arterial medial calcification in uremic rats: the role of mineralocorticoid receptor signaling in vascular calcification. Am J Physiol Renal Physiol 2015; 309:F967-79. [PMID: 26336165 DOI: 10.1152/ajprenal.00669.2014] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 08/27/2015] [Indexed: 01/03/2023] Open
Abstract
Vascular calcification (VC) is a critical complication in patients with chronic kidney disease (CKD). The effects of spironolactone (SPL), a mineralocorticoid receptor (MR) antagonist, on VC have not been fully investigated in CKD. The present in vivo study determined the protective effects of SPL on VC in CKD rats. Rats were divided into a control group and four groups of rats with adenine-induced CKD. Three groups were treated with 0, 50, and 100 mg·kg(-1)·day(-1) SPL for 8 wk, and one group was treated with 100 mg·kg(-1)·day(-1) SPL for the last 2 wk of the 8-wk treatment period. After 8 wk, CKD rats developed azotemia and hyperphosphatemia, with increases in the expression of serum and glucocorticoid-regulated kinase-1 and sodium-phosphate cotransporter, in inflammation and oxidative stress level, in osteogenic signaling and apoptosis, and in aortic calcification, compared with control rats. SPL dose dependently decreased these changes in the aortas, concomitant with improvements in renal inflammation, tubulointerstitial nephritis, and kidney function. SPL neither lowered blood pressure level nor induced hyperkalemia. Treatment of CKD rats for the last 2 wk with 100 mg·kg(-1)·day(-1) SPL attenuated VC compared with CKD rats with the same degree of kidney function and hyperphosphatemia. In conclusion, SPL dose dependently inhibits the progression of VC by suppressing MR signaling, local inflammation, osteogenic transition, and apoptosis in the aortas of CKD rats.
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Affiliation(s)
- Narihito Tatsumoto
- Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Shunsuke Yamada
- Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; Division of Internal Medicine, Fukuoka Dental College Medical and Dental Hospital, Fukuoka, Japan
| | - Masanori Tokumoto
- Division of Internal Medicine, Fukuoka Dental College Medical and Dental Hospital, Fukuoka, Japan
| | - Masahiro Eriguchi
- Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Hideko Noguchi
- Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Kumiko Torisu
- Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Kazuhiko Tsuruya
- Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; Department of Integrated Therapy for Chronic Kidney Disease, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; and
| | - Takanari Kitazono
- Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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Olauson H, Vervloet MG, Cozzolino M, Massy ZA, Ureña Torres P, Larsson TE. New insights into the FGF23-Klotho axis. Semin Nephrol 2015; 34:586-97. [PMID: 25498378 DOI: 10.1016/j.semnephrol.2014.09.005] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Abnormal mineral metabolism is a hallmark in patients with advanced chronic kidney disease (CKD). Hyperphosphatemia, and the homeostatic mechanisms controlling phosphate metabolism, have received particular attention over the past decade. The phosphate-regulating hormone fibroblast growth factor-23 (FGF23) was discovered through studies of rare hypophosphatemic disorders, whereas Klotho, which subsequently turned out to be a co-receptor for FGF23, was identified in a mouse model showing hyperphosphatemia and multiple aging-like traits. The FGF23-Klotho endocrine axis is a pivotal regulator of mineral metabolism. In CKD, early onset of Klotho deficiency contributes to renal FGF23 resistance and a maladaptive increase in circulating FGF23. FGF23 is an early biomarker of renal injury and increased FGF23 predicts adverse clinical outcomes, in particular cardiovascular disease. A paradigm of FGF23 excess and Klotho deficiency is proposed, in which FGF23 preferentially stimulates left ventricular hypertrophy, and loss of Klotho augments fibrosis, endothelial dysfunction, and vascular calcification. The clinical benefit of FGF23 and Klotho measurements remain uncertain, nevertheless, the FGF23-Klotho axis is a solid candidate for a novel diagnostic and therapeutic target in CKD.
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Affiliation(s)
- Hannes Olauson
- Division of Renal Medicine, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden
| | - Marc G Vervloet
- Department of Nephrology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands
| | - Mario Cozzolino
- Department of Health Sciences, University of Milan, Renal Division, San Paolo Hospital, Milan, Italy
| | - Ziad A Massy
- Inserm U-1088, Université de Picardie Jules Verne (UPJV), Amiens, France; Division of Nephrology, Ambroise Paré Hospital, Paris-Ile-de-France-Ouest University (Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)), Paris-Boulogne Billancourt, France
| | - Pablo Ureña Torres
- Service of Nephrology and Dialysis, Clinique du Landy and Department of Renal Physiology, Necker Hospital, University of Paris Descartes, Paris, France
| | - Tobias E Larsson
- Division of Renal Medicine, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden; Department of Nephrology, Karolinska University Hospital, Stockholm, Sweden.
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Abstract
The discovery of the Klotho (KL) gene, which was originally identified as a putative aging-suppressor gene, has generated tremendous interest and has advanced understanding of the aging process. In mice, the overexpression of the KL gene extends the life span, whereas mutations to the KL gene shorten the life span. The human KL gene encodes the α-Klotho protein, which is a multifunctional protein that regulates the metabolism of phosphate, calcium, and vitamin D. α-Klotho also may function as a hormone, although the α-Klotho receptor(s) has not been found. Point mutations of the KL gene in humans are associated with hypertension and kidney disease, which suggests that α-Klotho may be essential to the maintenance of normal renal function. Three α-Klotho protein types with potentially different functions have been identified: a full-length transmembrane α-Klotho, a truncated soluble α-Klotho, and a secreted α-Klotho. Recent evidence suggests that α-Klotho suppresses the insulin and Wnt signaling pathways, inhibits oxidative stress, and regulates phosphatase and calcium absorption. In this review, we provide an update on recent advances in the understanding of the molecular, genetic, biochemical, and physiological properties of the KL gene. Specifically, this review focuses on the structure of the KL gene and the factors that regulate KL gene transcription, the key sites in the regulation of α-Klotho enzyme activity, the α-Klotho signaling pathways, and the molecular mechanisms that underlie α-Klotho function. This current understanding of the molecular biology of the α-Klotho protein may offer new insights into its function and role in aging.
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Affiliation(s)
- Yuechi Xu
- Department of Physiology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
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Labonté ED, Carreras CW, Leadbetter MR, Kozuka K, Kohler J, Koo-McCoy S, He L, Dy E, Black D, Zhong Z, Langsetmo I, Spencer AG, Bell N, Deshpande D, Navre M, Lewis JG, Jacobs JW, Charmot D. Gastrointestinal Inhibition of Sodium-Hydrogen Exchanger 3 Reduces Phosphorus Absorption and Protects against Vascular Calcification in CKD. J Am Soc Nephrol 2014; 26:1138-49. [PMID: 25404658 DOI: 10.1681/asn.2014030317] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 07/23/2014] [Indexed: 02/02/2023] Open
Abstract
In CKD, phosphate retention arising from diminished GFR is a key early step in a pathologic cascade leading to hyperthyroidism, metabolic bone disease, vascular calcification, and cardiovascular mortality. Tenapanor, a minimally systemically available inhibitor of the intestinal sodium-hydrogen exchanger 3, is being evaluated in clinical trials for its potential to (1) lower gastrointestinal sodium absorption, (2) improve fluid overload-related symptoms, such as hypertension and proteinuria, in patients with CKD, and (3) reduce interdialytic weight gain and intradialytic hypotension in ESRD. Here, we report the effects of tenapanor on dietary phosphorous absorption. Oral administration of tenapanor or other intestinal sodium-hydrogen exchanger 3 inhibitors increased fecal phosphorus, decreased urine phosphorus excretion, and reduced [(33)P]orthophosphate uptake in rats. In a rat model of CKD and vascular calcification, tenapanor reduced sodium and phosphorus absorption and significantly decreased ectopic calcification, serum creatinine and serum phosphorus levels, circulating phosphaturic hormone fibroblast growth factor-23 levels, and heart mass. These results indicate that tenapanor is an effective inhibitor of dietary phosphorus absorption and suggest a new approach to phosphate management in renal disease and associated mineral disorders.
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Affiliation(s)
| | | | | | | | | | | | - Limin He
- Ardelyx, Inc., Fremont, California
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Razzaque MS. Bone-kidney axis in systemic phosphate turnover. Arch Biochem Biophys 2014; 561:154-8. [PMID: 24997362 DOI: 10.1016/j.abb.2014.06.031] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Revised: 06/18/2014] [Accepted: 06/24/2014] [Indexed: 12/20/2022]
Abstract
An adequate phosphate balance is essential for the maintenance of skeletal growth, development and function. It is also crucial in basic cellular functions, ranging from cell signaling to energy metabolism. Bone-derived fibroblast growth factor 23 (FGF23), through activating FGF receptor system, plays an important role in the systemic regulation of phosphate metabolism. Under physiological conditions, FGF23 exerts serum phosphate-lowering effects by inducing urinary phosphate excretion. Increased FGF23 activities are associated with hypophosphatemic diseases (i.e., rickets/osteomalacia), while reduced FGF23 activity are linked to hyperphosphatemic diseases (i.e., tumoral calcinosis). Unlike most of the FGF family members, FGF23 needs klotho, as a co-factor to activate its receptor system. In vivo studies have convincingly demonstrated that, in absence of klotho, FGF23 is unable to influence systemic phosphate metabolism. Available information suggests that interactions of FGF23, klotho, and FGFRs regulate renal phosphate metabolism by suppressing sodium-phosphate transporters in the proximal tubular epithelial cells. This article briefly summarizes how bone-kidney communication contributes to physiologic phosphate balance.
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Affiliation(s)
- Mohammed Shawkat Razzaque
- Department of Applied Oral Sciences, The Forsyth Institute, 245 First Street, Cambridge, MA 02142, USA.
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Vadakke Madathil S, Coe LM, Casu C, Sitara D. Klotho deficiency disrupts hematopoietic stem cell development and erythropoiesis. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 184:827-41. [PMID: 24412515 DOI: 10.1016/j.ajpath.2013.11.016] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 10/30/2013] [Accepted: 11/04/2013] [Indexed: 12/15/2022]
Abstract
Klotho deficiency is a characteristic feature of chronic kidney disease in which anemia and cardiovascular complications are prevalent. Disruption of the Klotho gene in mice results in hypervitaminosis D and a syndrome resembling accelerated aging that includes osteopenia and vascular calcifications. Given that the bone microenvironment and its cellular components considerably influence hematopoiesis, in the present study, we addressed the in vivo role of klotho in blood cell formation and differentiation. Herein, we report that genetic ablation of Klotho in mice results in a significant increase in erythropoiesis and a decrease in the hematopoietic stem cell pool size in the bone marrow, leading to impaired hematopoietic stem cell homing in vivo. Our data also suggest that high vitamin D levels are only partially responsible for these hematopoietic changes in Klotho(-/-) mice. Importantly, we found similar hematopoietic abnormalities in Klotho(-/-) fetal liver cells, suggesting that the effects of klotho in hematopoietic stem cell development are independent of the bone microenvironment. Finally, injection of klotho protein results in hematopoietic changes opposite to the ones observed in Klotho(-/-) mice. These observations unveil a novel role for the antiaging hormone klotho in the regulation of prenatal and postnatal hematopoiesis and provide new insights for the development of therapeutic strategies targeting klotho to treat hematopoietic disorders associated with aging.
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Affiliation(s)
- Sangeetha Vadakke Madathil
- Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York
| | - Lindsay M Coe
- Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York
| | - Carla Casu
- Department of Pediatric Hematology, Weill Cornell Medical College, New York
| | - Despina Sitara
- Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York; Department of Medicine, New York University School of Medicine, New York, New York.
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Abstract
Extracellular phosphate is toxic to the cell at high concentrations. When the phosphate level is increased in the blood by impaired urinary phosphate excretion, premature aging ensues. When the phosphate level is increased in the urine by dietary phosphate overload, this may lead to kidney damage (tubular injury and interstitial fibrosis). Extracellular phosphate exerts its cytotoxicity when it forms insoluble nanoparticles with calcium and fetuin-A, referred to as calciprotein particles (CPPs). CPPs are highly bioactive ligands that can induce various cellular responses, including osteogenic transformation of vascular smooth muscle cells and cell death in vascular endothelium and renal tubular epithelium. CPPs are detected in the blood of animal models and patients with chronic kidney disease (CKD) and associated with adaptation of the endocrine axes mediated by fibroblast growth factor-23 (FGF23) and Klotho that regulate mineral metabolism and aging. These observations have raised the possibility that CPPs may contribute to the pathophysiology of CKD. This notion, if validated, is expected to provide new diagnostic and therapeutic targets for CKD.
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46
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Shutto Y, Shimada M, Kitajima M, Yamabe H, Saitoh Y, Saitoh H, Razzaque MS. Inadequate awareness among chronic kidney disease patients regarding food and drinks containing artificially added phosphate. PLoS One 2013; 8:e78660. [PMID: 24236030 PMCID: PMC3827266 DOI: 10.1371/journal.pone.0078660] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 09/21/2013] [Indexed: 12/03/2022] Open
Abstract
Hyperphosphatemia is an important determinant of morbidity and mortality in patients with chronic kidney disease (CKD). Patients with CKD are advised to consume a low phosphate diet and are often prescribed phosphate-lowering drug therapy. However, commercially processed food and drinks often contain phosphate compounds, but the phosphate level is not usually provided in the ingredient list, which makes it difficult for CKD patients to choose a correct diet. We conducted a survey of the awareness of food/beverages containing artificially added phosphate among CKD patients undergoing hemodialysis. The subjects were 153 patients (77 males and 76 females; average age 56±11 years) who were randomly selected from the Dialysis Center of Hirosaki City, Japan. The subjects were provided with a list of questions. The survey results showed that 93% of the subjects were aware of the presence of high sugar content in soda, whereas only 25% were aware of the presence of phosphate (phosphoric acid) in such drinks. Despite 78% of the subjects being aware of the detrimental effects of consumption of a high phosphate diet, 43% drank at least 1 to 5 cans of soda per week and about 17% consumed “fast food” once each week. We also assessed the immediate effects of high-phosphate containing carbonated soda consumption by determining urinary calcium, phosphate, protein and sugar contents in overnight fasted healthy volunteers (n = 55; average age 20.7±0.3 years old, 20 males and 35 females). Significantly higher urinary calcium (adjusted using urinary creatinine) excretion was found 2 h after consuming 350 ml of carbonated soda compared to the fasting baseline level (0.15±0.01 vs. 0.09±0.01, p = 0.001). Our survey results suggest that CKD patients undergoing hemodialysis are not adequately aware of the hidden source of phosphate in their diet, and emphasize the need for educational initiatives to raise awareness of this issue among CKD patients.
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Affiliation(s)
- Yoshiko Shutto
- Department of Health Promotion, Hirosaki University Graduate School of Health Sciences, Hirosaki, Japan
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Kuro-o M. Klotho, phosphate and FGF-23 in ageing and disturbed mineral metabolism. Nat Rev Nephrol 2013; 9:650-60. [DOI: 10.1038/nrneph.2013.111] [Citation(s) in RCA: 188] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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48
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Hartman ML, Groppo F, Ohnishi M, Goodson JM, Hasturk H, Tavares M, Yaskell T, Floras C, Behbehani K, Razzaque MS. Can salivary phosphate levels be an early biomarker to monitor the evolvement of obesity? CONTRIBUTIONS TO NEPHROLOGY 2013; 180:138-48. [PMID: 23652556 PMCID: PMC3896993 DOI: 10.1159/000346793] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Phosphate is an essential nutrient required for important biological reactions that maintain the normal homoeostatic control of the cell. The adverse effects of phosphate metabolism in obesity have not been studied in detail, chiefly because such an association is thought to be uncommon. However, in some animal models of obesity, serum phosphate levels were noted to be higher than the nonobese controls. For example, leptin-deficient (ob/ob) mice become severely obese and have high serum phosphate levels. In this study, we analyzed the phosphate content in saliva collected from children (n = 77; 10.5 ± 1.8) to evaluate association with body mass index; there is a significant increase of salivary phosphate content in obese compared to normal-weight children (ANOVA p < 0.001). The correlation coefficient (r) between BMI and phosphate was 0.33 (p = 0.0032). Our results suggest that the human salivary phosphate level may be an early biomarker of the genesis of obesity in children. The diagnostic importance lies in the fact that the salivary phosphate level could provide a noninvasive predictive marker in the development of obesity. Further studies will be required to understand the underlying mechanism of increased salivary phosphate accumulation in obese and overweight children. Nevertheless, its occurrence without systemic changes could be of diagnostic value, particularly in monitoring evolvement of obesity.
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Affiliation(s)
- Mor-Li Hartman
- Department of Applied Oral Sciences, The Forsyth Institute, Cambridge, Mass
| | - Francisco Groppo
- Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil
| | - Mutsuko Ohnishi
- Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, Mass., USA
| | - J. Max Goodson
- Department of Applied Oral Sciences, The Forsyth Institute, Cambridge, Mass
| | - Hatice Hasturk
- Department of Applied Oral Sciences, The Forsyth Institute, Cambridge, Mass
| | - Mary Tavares
- Department of Applied Oral Sciences, The Forsyth Institute, Cambridge, Mass
| | - Tina Yaskell
- Department of Applied Oral Sciences, The Forsyth Institute, Cambridge, Mass
| | - Constantino Floras
- Department of Applied Oral Sciences, The Forsyth Institute, Cambridge, Mass
| | | | - Mohammed S. Razzaque
- Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, Mass., USA
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49
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Histochemical examination of vascular medial calcification of aorta in klotho-deficient mice. J Oral Biosci 2013. [DOI: 10.1016/j.job.2012.12.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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50
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Phosphate-induced autophagy counteracts vascular calcification by reducing matrix vesicle release. Kidney Int 2013; 83:1042-51. [PMID: 23364520 DOI: 10.1038/ki.2012.482] [Citation(s) in RCA: 160] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Autophagy is a dynamic and highly regulated process of self-digestion responsible for cell survival and reaction to oxidative stress. As oxidative stress is increased in uremia and is associated with vascular calcification, we studied the role of autophagy in vascular calcification induced by phosphate. In an in vitro phosphate-induced calcification model of vascular smooth muscle cells (VSMCs) and in an in vivo model of chronic renal failure, autophagy was inhibited by the superoxide dismutase mimic MnTMPyP, superoxide dismutase-2 overexpression, and by knockdown of the sodium-dependent phosphate cotransporter Pit1. Although phosphate-induced VSMC apoptosis was reduced by an inhibitor of autophagy (3-methyladenine) and knockdown of autophagy protein 5, calcium deposition in VSMCs was increased during inhibition of autophagy, even with the apoptosis inhibitor Z-VAD-FMK. An inducer of autophagy, valproic acid, decreased calcification. Furthermore, 3-methyladenine significantly promoted phosphate-induced matrix vesicle release with increased alkaline phosphatase activity. Thus, autophagy may be an endogenous protective mechanism counteracting phosphate-induced vascular calcification by reducing matrix vesicle release. Therapeutic agents influencing the autophagic response may be of benefit to treat aging or disease-related vascular calcification and osteoporosis.
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