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Poulsen SB, Murali SK, Thomas L, Assmus A, Rosenbæk LL, Nielsen R, Dimke H, Rieg T, Fenton RA. Genetic deletion of the kidney sodium/proton exchanger-3 (NHE3) does not alter calcium and phosphate balance due to compensatory responses. Kidney Int 2024:S0085-2538(24)00533-7. [PMID: 39089578 DOI: 10.1016/j.kint.2024.07.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 06/10/2024] [Accepted: 07/02/2024] [Indexed: 08/04/2024]
Abstract
The sodium/proton exchanger-3 (NHE3) plays a major role in acid-base and extracellular volume regulation and is also implicated in calcium homeostasis. As calcium and phosphate balances are closely linked, we hypothesized that there was a functional link between kidney NHE3 activity, calcium, and phosphate balance. Therefore, we examined calcium and phosphate homeostasis in kidney tubule-specific NHE3 knockout mice (NHE3loxloxPax8 mice). Compared to controls, these knockout mice were normocalcemic with no significant difference in urinary calcium excretion or parathyroid hormone levels. Thiazide-induced hypocalciuria was less pronounced in the knockout mice, in line with impaired proximal tubule calcium transport. Knockout mice had greater furosemide-induced calciuresis and distal tubule calcium transport pathways were enhanced. Despite lower levels of the sodium/phosphate cotransporters (NaPi)-2a and -2c, knockout mice had normal plasma phosphate, sodium-dependent 32Phosphate uptake in proximal tubule membrane vesicles and urinary phosphate excretion. Intestinal phosphate uptake was unchanged. Low dietary phosphate reduced parathyroid hormone levels and increased NaPi-2a and -2c abundances in both genotypes, but NaPi-2c levels remained lower in the knockout mice. Gene expression profiling suggested proximal tubule remodeling in the knockout mice. Acutely, indirect NHE3 inhibition using the SGLT2 inhibitor empagliflozin did not affect urinary calcium and phosphate excretion. No differences in femoral bone density or architecture were detectable in the knockout mice. Thus, a role for kidney NHE3 in calcium homeostasis can be unraveled by diuretics, but NHE3 deletion in the kidneys has no major effects on overall calcium and phosphate homeostasis due, at least in part, to compensating mechanisms.
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Affiliation(s)
- Søren B Poulsen
- Department of Biomedicine, Aarhus University, Aarhus DK-8000, Denmark
| | - Sathish K Murali
- Department of Biomedicine, Aarhus University, Aarhus DK-8000, Denmark; Department of Biomedical Sciences, University of Veterinary Medicine, Vienna, Austria
| | - Linto Thomas
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa
| | - Adrienne Assmus
- Department of Biomedicine, Aarhus University, Aarhus DK-8000, Denmark
| | - Lena L Rosenbæk
- Department of Biomedicine, Aarhus University, Aarhus DK-8000, Denmark
| | - Rikke Nielsen
- Department of Biomedicine, Aarhus University, Aarhus DK-8000, Denmark
| | - Henrik Dimke
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark; Department of Nephrology, Odense University Hospital, Odense, Denmark
| | - Timo Rieg
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa; James A. Haley Veterans' Hospital, Tampa, Florida, United States of America.
| | - Robert A Fenton
- Department of Biomedicine, Aarhus University, Aarhus DK-8000, Denmark.
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2
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Wilson R, Mukherjee-Roy N, Gattineni J. The role of fibroblast growth factor 23 in regulation of phosphate balance. Pediatr Nephrol 2024:10.1007/s00467-024-06395-5. [PMID: 38874635 DOI: 10.1007/s00467-024-06395-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Revised: 04/22/2024] [Accepted: 04/22/2024] [Indexed: 06/15/2024]
Abstract
Phosphate is essential for numerous biological processes, and serum levels are tightly regulated to accomplish these functions. The regulation of serum phosphate in a narrow physiological range is a well-orchestrated process and involves the gastrointestinal (GI) tract, bone, kidneys, and several hormones, namely, parathyroid hormone, fibroblast growth factor 23 (FGF23), and 1,25-dihydroxyvitamin D (1,25 Vitamin D). Although primarily synthesized in the bone, FGF23, an endocrine FGF, acts on the kidney to regulate phosphate and Vitamin D homeostasis by causing phosphaturia and reduced levels of 1,25 Vitamin D. Recent studies have highlighted the complex regulation of FGF23 including transcriptional and post-translational modification and kidney-bone cross talk. Understanding FGF23 biology has led to the identification of novel therapeutic agents to treat diseases that disrupt phosphate metabolism secondary to FGF23. The focus of this review is to provide an overview of phosphate homeostasis, FGF23 biology, and the role of FGF23 in phosphate balance.
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Affiliation(s)
| | - Neije Mukherjee-Roy
- Division of Pediatric Nephrology, Department of Pediatrics, The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, USA
| | - Jyothsna Gattineni
- Division of Pediatric Nephrology, Department of Pediatrics, The University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, USA.
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3
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Vervloet MG. Shedding Light on the Complex Regulation of FGF23. Metabolites 2022; 12:metabo12050401. [PMID: 35629904 PMCID: PMC9147863 DOI: 10.3390/metabo12050401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 04/23/2022] [Accepted: 04/26/2022] [Indexed: 12/10/2022] Open
Abstract
Early research has suggested a rather straightforward relation between phosphate exposure, increased serum FGF23 (Fibroblast Growth Factor 23) concentrations and clinical endpoints. Unsurprisingly, however, subsequent studies have revealed a much more complex interplay between autocrine and paracrine factors locally in bone like PHEX and DMP1, concentrations of minerals in particular calcium and phosphate, calciprotein particles, and endocrine systems like parathyroid hormone PTH and the vitamin D system. In addition to these physiological regulators, an expanding list of disease states are shown to influence FGF23 levels, usually increasing it, and as such increase the burden of disease. While some of these physiological or pathological factors, like inflammatory cytokines, may partially confound the association of FGF23 and clinical endpoints, others are in the same causal path, are targetable and hence hold the promise of future treatment options to alleviate FGF23-driven toxicity, for instance in chronic kidney disease, the FGF23-associated disease with the highest prevalence by far. These factors will be reviewed here and their relative importance described, thereby possibly opening potential means for future therapeutic strategies.
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Affiliation(s)
- Marc G. Vervloet
- Amsterdam UMC, Location Vrije Universiteit Amsterdam, Nephrology, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands; ; Tel.: +31-20-4442671
- Amsterdam Cardiovascular Sciences, Diabetes and Metabolism, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands
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4
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Genetic Disorders of Calcium and Phosphorus Metabolism. ENDOCRINES 2022. [DOI: 10.3390/endocrines3010014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
In this review, we describe genetic mutations affecting metabolic pathways of calcium and phosphorus homeostasis. Calcium and phosphorus homeostasis has tight hormonal regulation by three major hormones: vitamin D, parathyroid hormone (PTH) and fibroblast growth factor 23 (FGF23). We describe the physiology and pathophysiology of disorders, their biochemical profile, clinical characteristics, diagnostics, and treatments.
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5
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Jindal S, Moorthy JN. Zwitterionic Luminescent 2D Metal-Organic Framework Nanosheets (LMONs): Selective Turn-On Fluorescence Sensing of Dihydrogen Phosphate. Inorg Chem 2022; 61:3942-3950. [PMID: 35191671 DOI: 10.1021/acs.inorgchem.1c03547] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
While a plethora of organic linkers based on carboxylic acids have been utilized in the construction of MOFs, zwitterionic linkers that typify the attributes of naturally occurring amino acids have been exploited only scarcely to the best of our knowledge. Zwitterionic interior characteristics should be expected to impart unique properties to the resultant MOFs with a high potential to interact with guest species through electrostatic interactions. In our investigations with bis(p-carboxyphenyl)imidazolylarenes as a novel class of linkers for the development of functional MOFs, we have found that bisimidazole-tetracarboxylic acid H4DMBI undergoes metal-assisted self-assembly with Zn(NO3)2 to yield a layered MOF (Zn-DMBI). In the latter, the linker serves as a two-connecting linker with imidazoles and carboxylic acids behaving as zwitterions. The layers are offset stacked in the crystal structure and are bound firmly by hydrogen bonds between imidazolium and carboxylate ions. Such a packing precludes fluorescence from being observed due to self-quenching. However, exfoliation into zwitterionic 2D metal-organic nanosheets (MONs) by sonication in methanol for 1 h liberates palpable fluorescence. Furthermore, the suspension of luminescent MONs (LMONs) in methanol permits selective sensing of anions; in particular, dihydrogen phosphate (H2PO4-) that is complementary to the zwitterions in terms of hydrogen bond donor and acceptor sites is observed with fluorescence enhancement by 120%, leading to its detection at a sub-parts-per-million (0.13 ppm) level. Thus, access to zwitterionic 2D MONs and their application for selective anion sensing with "turn-on" fluorescence are demonstrated by a rational de novo bottom-up approach.
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Affiliation(s)
- Swati Jindal
- Department of Chemistry, Indian Institute of Technology, Kanpur 208016, India
| | - Jarugu Narasimha Moorthy
- Department of Chemistry, Indian Institute of Technology, Kanpur 208016, India.,School of Chemistry, Indian Institute of Science Education and Research, Thiruvananthapuram 695551, India
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6
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Yakubov R, Ayman A, Klein Kremer A, Bael A, van den Akker M. Unusual presentation of a five-month-old boy with NaPi2a homozygous mutation without hyperphosphaturia: Case report and review of the literature. Clin Case Rep 2021; 9:e04740. [PMID: 34532044 PMCID: PMC8435227 DOI: 10.1002/ccr3.4740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 07/15/2021] [Accepted: 08/09/2021] [Indexed: 11/10/2022] Open
Abstract
Deletions of the NaPi2a gene and mutations in the SLC34A gene should be considered in patients with atypical presentation, without phosphaturia, with mild hypo to normal phosphatemia, and nephrocalcinosis.
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Affiliation(s)
- Renata Yakubov
- Department of PediatricsHillel Yaffe Medical CenterHaderaIsrael
- Nephrology UnitHillel Yaffe Medical CenterHaderaIsrael
| | - Asaly Ayman
- Department of PediatricsHillel Yaffe Medical CenterHaderaIsrael
| | | | - An Bael
- Department of PediatricsZNA Queen Paola Children’s HospitalAntwerpBelgium
- Pediatric NephrologyZNA Queen Paola Children’s HospitalAntwerpBelgium
- Faculty of MedicineUniversity of AntwerpAntwerpBelgium
| | - Machiel van den Akker
- Department of PediatricsZNA Queen Paola Children’s HospitalAntwerpBelgium
- Faculty of MedicineUniversity of AntwerpAntwerpBelgium
- Department of Pediatric Hematology OncologyUZ BrusselBrusselsBelgium
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7
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Papadopoulou A, Bountouvi E, Karachaliou FE. The Molecular Basis of Calcium and Phosphorus Inherited Metabolic Disorders. Genes (Basel) 2021; 12:genes12050734. [PMID: 34068220 PMCID: PMC8153134 DOI: 10.3390/genes12050734] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 04/30/2021] [Accepted: 05/05/2021] [Indexed: 02/07/2023] Open
Abstract
Calcium (Ca) and Phosphorus (P) hold a leading part in many skeletal and extra-skeletal biological processes. Their tight normal range in serum mirrors their critical role in human well-being. The signalling “voyage” starts at Calcium Sensing Receptor (CaSR) localized on the surface of the parathyroid glands, which captures the “oscillations” of extracellular ionized Ca and transfers the signal downstream. Parathyroid hormone (PTH), Vitamin D, Fibroblast Growth Factor (FGF23) and other receptors or ion-transporters, work synergistically and establish a highly regulated signalling circuit between the bone, kidneys, and intestine to ensure the maintenance of Ca and P homeostasis. Any deviation from this well-orchestrated scheme may result in mild or severe pathologies expressed by biochemical and/or clinical features. Inherited disorders of Ca and P metabolism are rare. However, delayed diagnosis or misdiagnosis may cost patient’s quality of life or even life expectancy. Unravelling the thread of the molecular pathways involving Ca and P signaling, we can better understand the link between genetic alterations and biochemical and/or clinical phenotypes and help in diagnosis and early therapeutic intervention.
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8
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Li Z, Liu G, Fan C, Pu S. Ratiometric fluorescence for sensitive detection of phosphate species based on mixed lanthanide metal organic framework. Anal Bioanal Chem 2021; 413:3281-3290. [PMID: 33693975 DOI: 10.1007/s00216-021-03264-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 02/19/2021] [Accepted: 03/01/2021] [Indexed: 12/31/2022]
Abstract
Phosphate (PO43-) plays a major role in aquatic ecosystems and biosystems. Developing a highly sensitive and selective ratiometric fluorescence probe for detection of PO43- is of great significance to the ecological environment and human health. In this work, a novel dual lanthanide metal organic framework was synthesized via hydrothermal reaction based on Tb3+ and Ce3+ as the center metal ions and terephthalic acid as the organic ligand (designated as Tb-Ce-MOFs). The fluorescence of Tb-Ce-MOFs shows emission at 375 nm. In the presence of PO43-, with increased concentration of PO43-, the fluorescence intensity of Tb-Ce-MOFs at 500 nm and 550 nm increased, while the intensity at 375 nm was reduced. Hence, ratiometric fluorescence detecting of PO43- can be achieved by measuring the ratio of fluorescence at 550 nm (FL550) to 375 nm (FL375) in the fluorescent spectra of the Tb-Ce-MOFs. In this sensing approach, the Tb-Ce-MOFs probe exhibits highly sensitive and selective for detection of PO43-. The limit of detection is calculated to be 28 nM and the detection range is 0.1 to 10 μM. In addition, the Tb-Ce-MOFs were used in the detection of PO43- in real samples. We design and synthesize a mixed lanthanide metal organic framework fluorescence probe (Tb-Ce-MOFs) for ratiometric fluorescence for the detection of PO43- based on Tb3+ and Ce3+ as the center metal ions and terephthalic acid as the organic ligand.
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Affiliation(s)
- Zhijian Li
- Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, Nanchang, 330013, Jiangxi, China.
- Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science and Engineering, Fudan University, Shanghai, 200433, China.
| | - Gang Liu
- Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, Nanchang, 330013, Jiangxi, China
| | - Congbin Fan
- Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, Nanchang, 330013, Jiangxi, China
| | - Shouzhi Pu
- Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, Nanchang, 330013, Jiangxi, China.
- YuZhang Normal University, Nanchang, 330013, Jiangxi, China.
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9
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Rodríguez-Rubio E, Gil-Peña H, Chocron S, Madariaga L, de la Cerda-Ojeda F, Fernández-Fernández M, de Lucas-Collantes C, Gil M, Luis-Yanes MI, Vergara I, González-Rodríguez JD, Ferrando S, Antón-Gamero M, Carrasco Hidalgo-Barquero M, Fernández-Escribano A, Fernández-Maseda MÁ, Espinosa L, Oliet A, Vicente A, Ariceta G, Santos F. Phenotypic characterization of X-linked hypophosphatemia in pediatric Spanish population. Orphanet J Rare Dis 2021; 16:104. [PMID: 33639975 PMCID: PMC7912818 DOI: 10.1186/s13023-021-01729-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 02/03/2021] [Indexed: 11/26/2022] Open
Abstract
Background X-linked hypophosphatemia (XLH) is a hereditary rare disease caused by loss-of-function mutations in PHEX gene leading tohypophosphatemia and high renal loss of phosphate. Rickets and growth retardation are the major manifestations of XLH in children, but there is a broad phenotypic variability. Few publications have reported large series of patients. Current data on the clinical spectrum of the disease, the correlation with the underlying gene mutations, and the long-term outcome of patients on conventional treatment are needed, particularly because of the recent availability of new specific medications to treat XLH. Results The RenalTube database was used to retrospectively analyze 48 Spanish patients (15 men) from 39 different families, ranging from 3 months to 8 years and 2 months of age at the time of diagnosis (median age of 2.0 years), and with XLH confirmed by genetic analysis. Bone deformities, radiological signs of active rickets and growth retardation were the most common findings at diagnosis. Mean (± SEM) height was − 1.89 ± 0.19 SDS and 55% (22/40) of patients had height SDS below—2. All cases had hypophosphatemia, serum phosphate being − 2.81 ± 0.11 SDS. Clinical manifestations and severity of the disease were similar in both genders. No genotype—phenotype correlation was found. Conventional treatment did not attenuate growth retardation after a median follow up of 7.42 years (IQR = 11.26; n = 26 patients) and failed to normalize serum concentrations of phosphate. Eleven patients had mild hyperparathyroidism and 8 patients nephrocalcinosis. Conclusions This study shows that growth retardation and rickets were the most prevalent clinical manifestations at diagnosis in a large series of Spanish pediatric patients with XLH confirmed by mutations in the PHEX gene. Traditional treatment with phosphate and vitamin D supplements did not improve height or corrected hypophosphatemia and was associated with a risk of hyperparathyroidism and nephrocalcinosis. The severity of the disease was similar in males and females.
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Affiliation(s)
| | - Helena Gil-Peña
- AGC Pediatría, Hospital Universitario Central de Asturias, Oviedo, Spain
| | - Sara Chocron
- Servicio de Nefrología Pediátrica, Hospital Vall D'Hebron, Universitat Autónoma de Barcelona, Barcelona, Spain
| | - Leire Madariaga
- Servicio Nefrología Pediátrica, IIS Biocruces-Bizkaia, Universidad del País Vasco UPV/EHU, Hospital Universitario Cruces, Barakaldo, Spain
| | | | | | | | - Marta Gil
- Servicio Pediatría, Hospital Universitario de Santiago de Compostela, Santiago de Compostela, Spain
| | - María Isabel Luis-Yanes
- Servicio Pediatría, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, Spain
| | - Inés Vergara
- Servicio Pediatría, Complexo Hospitalario Universitario A Coruña (CHUAC), A Coruña, Spain
| | | | - Susana Ferrando
- Servicio de Pediatría, Hospital Clínico Universitario de Valencia, Valencia, Spain
| | | | | | | | | | - Laura Espinosa
- Servicio Nefrología infantile, Hospital Universitario Infantil La Paz, Madrid, Spain
| | - Aniana Oliet
- Servicio Nefrología, Hospital Severo Ochoa, Leganés, Spain
| | | | - Gema Ariceta
- Servicio de Nefrología Pediátrica, Hospital Vall D'Hebron, Universitat Autónoma de Barcelona, Barcelona, Spain
| | - Fernando Santos
- Pediatric Research, Medicine Department, University of Oviedo, Oviedo, Spain.,AGC Pediatría, Hospital Universitario Central de Asturias, Oviedo, Spain
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10
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Kumar P, Pachisia S, Gupta R. Turn-on detection of assorted phosphates by luminescent chemosensors. Inorg Chem Front 2021. [DOI: 10.1039/d1qi00032b] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
This review illustrates a variety of luminescent chemosensors for the selective detection of assorted phosphates via the “Turn-On” emission mechanism with focus on their design aspects, chemical structures and sensing mechanism.
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Affiliation(s)
- Pramod Kumar
- Department of Chemistry
- University of Delhi
- Delhi-110007
- India
| | - Sanya Pachisia
- Department of Chemistry
- University of Delhi
- Delhi-110007
- India
| | - Rajeev Gupta
- Department of Chemistry
- University of Delhi
- Delhi-110007
- India
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11
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Vervloet MG. FGF23 measurement in chronic kidney disease: What is it really reflecting? Clin Chim Acta 2020; 505:160-166. [PMID: 32156608 DOI: 10.1016/j.cca.2020.03.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 03/05/2020] [Accepted: 03/06/2020] [Indexed: 12/20/2022]
Abstract
Fibroblast growth factor can be measured in clinical practice using ELISA, with acceptable validity. Different from many metabolites and minerals, its value can differ by a thousand-fold between individuals, largely because of differences in kidney function and dietary habits. This wide range complicates the proper interpretation of the concentration of FGF23, both in terms of the appropriateness of a given value for a given estimated GFR, and in terms of estimating the magnitude of risk for clinical events, with which FGF23 is clearly associated. In this narrative review, the impact of kidney function, exposure to phosphate from diet, and novel emerging factors that influence FGF23 concentrations are discussed. These and yet to define determinants of FGF23 question the causality of the association of FGF23 with hard (cardiovascular) endpoints, as observed in several epidemiological studies.
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Affiliation(s)
- Marc G Vervloet
- Amsterdam University Medical Center, Department of Nephrology, and Amsterdam Cardiovascular Sciences (ACS), Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands.
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12
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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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13
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Abstract
Hypophosphatemic rickets, mostly of the X-linked dominant form caused by pathogenic variants of the PHEX gene, poses therapeutic challenges with consequences for growth and bone development and portends a high risk of fractions and poor bone healing, dental problems and nephrolithiasis/nephrocalcinosis. Conventional treatment consists of PO4 supplements and calcitriol requiring monitoring for treatment-emergent adverse effects. FGF23 measurement, where available, has implications for the differential diagnosis of hypophosphatemia syndromes and, potentially, treatment monitoring. Newer therapeutic modalities include calcium sensing receptor modulation (cinacalcet) and biological molecules targeting FGF23 or its receptors. Their long-term effects must be compared with those of conventional treatments.
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Affiliation(s)
- Martin Bitzan
- Department of Pediatrics, The Montreal Children's Hospital, McGill University Health Centre, 1001 Boulevard Décarie, Room B RC.6164, Montreal, Quebec H4A 3J1, Canada.
| | - Paul R Goodyer
- The Research Institute of the McGill University Health Centre, 1001 Boulevard Décarie, Room EM1.2232, Montreal, Quebec H4A3J1, Canada
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14
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Hu MC, Shi M, Moe OW. Role of αKlotho and FGF23 in regulation of type II Na-dependent phosphate co-transporters. Pflugers Arch 2018; 471:99-108. [PMID: 30506274 DOI: 10.1007/s00424-018-2238-5] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 11/16/2018] [Accepted: 11/18/2018] [Indexed: 11/26/2022]
Abstract
Alpha-Klotho is a member of the Klotho family consisting of two other single-pass transmembrane proteins: βKlotho and γKlotho; αKlotho has been shown to circulate in the blood. Fibroblast growth factor (FGF)23 is a member of the FGF superfamily of 22 genes/proteins. αKlotho serves as a co-receptor with FGF receptors (FGFRs) to provide a receptacle for physiological FGF23 signaling including regulation of phosphate metabolism. The extracellular domain of transmembrane αKlotho is shed by secretases and released into blood circulation (soluble αKlotho). Soluble αKlotho has both FGF23-independent and FGF23-dependent roles in phosphate homeostasis by modulating intestinal phosphate absorption, urinary phosphate excretion, and phosphate distribution into bone in concerted interaction with other calciophosphotropic hormones such as PTH and 1,25-(OH)2D. The direct role of αKlotho and FGF23 in the maintenance of phosphate homeostasis is partly mediated by modulation of type II Na+-dependent phosphate co-transporters in target organs. αKlotho and FGF23 are principal phosphotropic hormones, and the manipulation of the αKlotho-FGF23 axis is a novel therapeutic strategy for genetic and acquired phosphate disorders and for conditions with FGF23 excess and αKlotho deficiency such as chronic kidney disease.
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Affiliation(s)
- Ming Chang Hu
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX, 75390, USA.
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA.
| | - Mingjun Shi
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX, 75390, USA
| | - Orson W Moe
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX, 75390, USA.
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA.
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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15
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Bech AP, Hoorn EJ, Zietse R, Wetzels JFM, Nijenhuis T. Yield of diagnostic tests in unexplained renal hypophosphatemia: a case series. BMC Nephrol 2018; 19:220. [PMID: 30180816 PMCID: PMC6123988 DOI: 10.1186/s12882-018-1017-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 08/27/2018] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Isolated renal hypophosphatemia may be inherited or acquired. An increasing number of patients with unexplained renal hypophosphatemia is being referred to our clinics, but the optimal diagnostic work-up is not known. Therefore, the aim of this study was to assess the diagnostic yield in these patients. METHODS We retrospectively evaluated all patients who were referred because of unexplained isolated renal hypophosphatemia to two academic tertiary referral centers in The Netherlands in the period of 2013-2017. RESULTS We evaluated 17 patients. In five female patients renal hypophosphatemia could be attributed to the use of oral contraceptives. The other 12 patients had a median age of 48 years (10 males). There were no other signs of tubulopathy and none of the patients used drugs known to be associated with hypophosphatemia. FGF23 levels were above normal (> 125 RU/ml) in 2/12 patients. Genetic testing, performed in all patients, did not identify a mutation in genes known to be associated with renal phosphate wasting. A scan with a radiolabeled somatostatin analogue was performed in 8 patients. In one patient, with an FGF23 level of 110 RU/ml, an increased uptake of the somatostatin analog was observed due to tumor induced osteomalacia (TIO). CONCLUSIONS Oral contraceptive use is an important but under-recognized cause of renal hypophosphatemia. The cause of isolated renal hypophosphatemia remained unexplained in the majority of other patients despite extensive and expensive additional investigations. The pre-test probability for tumor-induced osteomalacia or inherited renal hypophosphatemia in a patient with aspecific complaints and a normal FGF23 level is low. Further research is needed to investigate which patients should be screened for TIO. At present we suggest to perform somatostatin scans only in patients with severe complaints, elevated FGF23 levels, or progressive disease.
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Affiliation(s)
- A P Bech
- Department of Nephrology, Radboud university medical center, Nijmegen, The Netherlands.
| | - E J Hoorn
- Department of Internal Medicine, Division of Nephrology and Transplantation, Erasmus medical center, Rotterdam, The Netherlands
| | - R Zietse
- Department of Internal Medicine, Division of Nephrology and Transplantation, Erasmus medical center, Rotterdam, The Netherlands
| | - J F M Wetzels
- Department of Nephrology, Radboud university medical center, Nijmegen, The Netherlands
| | - T Nijenhuis
- Department of Nephrology, Radboud university medical center, Nijmegen, The Netherlands
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Wu H, Tong C. A Specific Turn-On Fluorescent Sensing for Ultrasensitive and Selective Detection of Phosphate in Environmental Samples Based on Antenna Effect-Improved FRET by Surfactant. ACS Sens 2018; 3:1539-1545. [PMID: 30044086 DOI: 10.1021/acssensors.8b00343] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Phosphate is not only an important indicator for aquatic ecosystems, but also plays vital roles in biosystems. A new strategy for ultrasensitive and selective detection of phosphate is fabricated based on a new insight found in this paper, in which a lower concentration of surfactant sodium dodecylbenzenesulfonate (SDBS) can greatly induce fluorescence resonance energy transfer (FRET) from ciprofloxacin (CIP) to Eu3+ in the CIP-Eu3+ complex. Surfactant SDBS does not act as a sensitizer for enhancing the fluorescence intensity of the system, but acts as a sensitizer of FRET and makes the native fluorescence of CIP quenched completely (switch off). Eu3+ ions can coordinate with the oxygen-donor atoms of phosphate, which weakens FRET from CIP to Eu3+ and results in the fluorescence recovery of CIP (turn on). The multicomplex of the CIP-Eu3+-phosphate has more sensitive fluorescent response than that of the reported coordination nanoparticle-based fluorescent probes. The LOD (S/N = 3) of this sensing system can attain 4.3 nM. The possible interferential substances existing in environmental samples, such as 17 common metal ions, 11 anions, and fulvic acid investigated, do not interfere with the phosphate detection. This sensing system has been successfully applied for phosphate detection in environmental samples such as wastewater, surface water, and atmospheric particulates. This work not only develops a fluorescent probe for the phosphate detection, but also provides a new strategy for designing fluorescent probes based on FRET or coordination nanoparticles.
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Affiliation(s)
- Huifang Wu
- Key Laboratory of Environmental Remediation and Ecological Health, Ministry of Education, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Changlun Tong
- Key Laboratory of Environmental Remediation and Ecological Health, Ministry of Education, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
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17
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Maia MLDA, Abreu ALS, Nogueira PCK, Val MLDMD, Carvalhaes JTDA, Andrade MCD. HYPOPHOSPHATEMIC RICKETS: CASE REPORT. ACTA ACUST UNITED AC 2018; 36:242-247. [PMID: 29617471 PMCID: PMC6038795 DOI: 10.1590/1984-0462/;2018;36;2;00009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 05/16/2017] [Indexed: 11/22/2022]
Abstract
OBJECTIVE Early diagnosis and immediate treatment of hypophosphatemic rickets is of utmost importance as it may prevent subsequent sequelae. This report aims at warning pediatricians to consider the presence of the disease. CASE DESCRIPTION Description of the metabolic profile, creatinine clearance, nutritional status, weight and body structure of a patient who presented the clinical-laboratorial characteristics of hypophosphatemic rickets and was followed in an outpatient clinic for tubulopathies over the period of 12 months. The patient had been bedridden for some time, was dependent on mechanical ventilation and presented an altered metabolic bone condition. Treatment was phosphate (initial: 65 mg/kg/day and final: 24,2 mg/kg/day), calcium (initial: 127 mg/kg/day, final: 48,4 mg/kg/day) and calcitriol (initial: 0.06 mcg/kg/day, final: 0.03 mcg/kg/day). The patient improved, evolving into spontaneous breathing and walking unaided. Laboratory results: calcium (mg/dL) initial 7.1, final 10.1; phosphate (mg/dL) initial 1.7 final 3.2; magnesium (mg/dL) initial 1.5 final 2.1, parathyroid hormone (pg/l) initial 85.8, final 52.7, alkaline phosphatase (UI/l) initial 12660, final 938; there was also improvement in weight/structural development (Z score: H/A initial: -6.05, final -3.64; W/A: initial -2.92, final -1.57) with presence of transitory gallstones. Creatinine clearance (mL/min/1.73m2bsa) was constant. The medication improved his laboratory results and nutritional status, but the patient did not return for two years for follow-up and, during this period, his condition has noticeably deteriorated. COMMENTS Early diagnosis and follow-up are essential in dealing with this pathology.
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18
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Asadzadeh Manjili F, Bakhshi Aliabad MH, Kalantar SM, Sahebzamani A, Safa A. Molecular and Biochemical Aspects of Hypophosphatemic Rickets; an Updated Review. INTERNATIONAL JOURNAL OF BASIC SCIENCE IN MEDICINE 2017. [DOI: 10.15171/ijbsm.2017.22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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19
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Georges GT, Nájera O, Sowers K, Sowers JR. Fibroblast Growth Factor 23 and Hypophosphatemia: A Case of Hypophosphatemia along the Rickets-Osteomalacia Spectrum. Cardiorenal Med 2016; 7:60-65. [PMID: 27994603 DOI: 10.1159/000449476] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Phosphorus is a key component of bone, and a deficiency results in poor mineralization along with other systemic symptoms of hypophosphatemia. Various causes of hypophosphatemia with renal wasting of phosphorus have been identified. These include the Fanconi syndrome, various genetic mutations of fibroblast growth factor 23 (FGF23) handling and the sodium/phosphate cotransporter, and those due to FGF23 secretion by mesenchymal tumors. Depending on the cause, vitamin D metabolism may also be impaired, which may amplify the deficiency in phosphorus and render treatment more challenging. Here, we report a case of hypophosphatemia and multiple stress fractures in a 20-year-old male college student living with chronic bone pain and anxiety about suffering further fractures. We further review the literature regarding this spectrum.
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Affiliation(s)
- George T Georges
- Diabetes and Cardiovascular Center, Department of Medicine, University of Missouri, Columbia, Mo., USA
| | - O Nájera
- Diabetes and Cardiovascular Center, Department of Medicine, University of Missouri, Columbia, Mo., USA
| | - Kurt Sowers
- Department of Medicine, Touro University, Henderson, Nev., USA
| | - James R Sowers
- Diabetes and Cardiovascular Center, Department of Medicine, University of Missouri, Columbia, Mo., USA; Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Mo., USA; Harry S. Truman VA Hospital, Columbia, Mo., USA
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20
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Cuervo C, Abitbol CL, Zilleruelo GE, Freundlich M. Fibroblast growth factor-23 and renin-angiotensin system levels in vitamin-D-dependent rickets type I. Pediatr Nephrol 2016; 31:1189-93. [PMID: 26939683 DOI: 10.1007/s00467-016-3356-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2015] [Revised: 02/12/2016] [Accepted: 02/13/2016] [Indexed: 12/20/2022]
Abstract
BACKGROUND As 1,25(OH)2D3 vitamin D3 induces fibroblast growth factor-23 (FGF-23) production and suppresses the renin-angiotensin-aldosterone system (RAAS), its absence in vitamin-D-dependent rickets type I (VDDR-I) may have adverse health consequences. CASE DESCRIPTION An infant presented at age 8 months with hypocalcemia and rickets and very low 1,25(OH)2D3 levels. Genetic analysis confirmed VDRR-I, and calcitriol therapy was initiated. During periods of nonadherence to therapy, chemical measurements revealed detectable FGF-23 levels, with undetectable 1,25(OH)2D3, hypophosphatemia, low tubular reabsorption of phosphate, hypocalcemia, and very elevated parathyroid hormone (PTH) levels. These changes, in addition to elevated RAAS levels, normalized during calcitriol therapy despite elevated FGF-23 levels. At age 12 years, all rachitic manifestations were absent, and bone mineral density (BMD) and the echocardiogram were normal. CONCLUSIONS Whereas 1,25(OH)2D3 is not indispensable for FGF-23 production, PTH in the absence of vitamin D may maintain FGF-23 secretion despite hypocalcemia. Normalization of urinary phosphate losses despite elevated FGF-23 during calcitriol-mediated suppression of secondary hyperparathyroidism points to a cardinal role of PTH as a cause of the phosphaturia in VDRR-I. Normalization of RAAS by calcitriol may conceivably prevent adverse cardiovascular outcomes.
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Affiliation(s)
- Carlos Cuervo
- Division of Pediatric Nephrology, University of Miami Miller School of Medicine, PO Box 016960(M-714), Miami, FL, 33101, USA
| | - Carolyn L Abitbol
- Division of Pediatric Nephrology, University of Miami Miller School of Medicine, PO Box 016960(M-714), Miami, FL, 33101, USA
| | - Gaston E Zilleruelo
- Division of Pediatric Nephrology, University of Miami Miller School of Medicine, PO Box 016960(M-714), Miami, FL, 33101, USA
| | - Michael Freundlich
- Division of Pediatric Nephrology, University of Miami Miller School of Medicine, PO Box 016960(M-714), Miami, FL, 33101, USA.
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Effect of phosphorus supplementation on weight gain and waist circumference of overweight/obese adults: a randomized clinical trial. Nutr Diabetes 2015; 5:e189. [PMID: 26690287 PMCID: PMC4735052 DOI: 10.1038/nutd.2015.38] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 10/19/2015] [Accepted: 11/10/2015] [Indexed: 11/25/2022] Open
Abstract
Background: Phosphorus status is inversely correlated with body weight; however, the effect of phosphorus supplementation on body weight in a controlled design has not been studied. Methods: This is a double-blind, randomized, placebo-controlled trial of 63 adults aged 18–45 years with a body mass index (BMI) of ⩾25 kg m−2 and normal kidney function at the American University of Beirut. Participants were randomly assigned to the placebo or phosphorus group where daily placebo or phosphorus supplements were ingested with three main meals (breakfast, lunch and dinner) for a period of 12 weeks. Primary outcomes were changes in anthropometric measures, blood metabolites (including lipid profile, glucose and insulin) and subjective appetite scores. The trial is registered with Clinical Trial.gov, NCT02329990. Results: Body weight was significantly lower in the phosphorus group when compared with the placebo group (−0.65 kg (95% confidence interval (CI) −1.69 to 0.40) vs 1.13 kg (95% CI 0.19 to 2.06), P=0.01). Similarly, BMI and waist circumference were significantly lower in the phosphorus group when compared with the placebo group (−0.24 kg m−2 (95% CI −0.59 to 0.12) vs 0.42 kg m−2 (95% CI 0.05 to 0.78), P=0.01; −3.62 cm (95% CI−4.90 to −2.33) vs 0.38 cm ( 95% CI−0.44 to 1.20), P<0.001; respectively). Several parameters of subjective appetite scores were decreased in the phosphorus-supplemented group. Conclusions: Phosphorus supplementation for 12 weeks significantly decreases body weight, BMI, waist circumference and subjective appetite scores. These findings support a promising role of the mineral phosphorus in the prevention and management of obesity, especially abdominal adiposity. The exact mechanisms of action and longer-term effects still need to be elucidated.
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22
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Diener S, Schorpp K, Strom TM, Hadian K, Lorenz-Depiereux B. Development of A Cell-Based Assay to Identify Small Molecule Inhibitors of FGF23 Signaling. Assay Drug Dev Technol 2015; 13:476-87. [DOI: 10.1089/adt.2015.653] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Affiliation(s)
- Susanne Diener
- German Research Center for Environmental Health, Institute of Human Genetics, HelmholtzZentrum München, Neuherberg, Bavaria, Germany
| | - Kenji Schorpp
- Assay Development and Screening Platform, German Research Center for Environmental Health, Institute of Molecular Toxicology and Pharmacology, HelmholtzZentrum München, Neuherberg, Bavaria, Germany
| | - Tim-Matthias Strom
- German Research Center for Environmental Health, Institute of Human Genetics, HelmholtzZentrum München, Neuherberg, Bavaria, Germany
- Institute of Human Genetics, Klinikum rechts der Isar der Technischen Universität München, Munich, Bavaria, Germany
| | - Kamyar Hadian
- Assay Development and Screening Platform, German Research Center for Environmental Health, Institute of Molecular Toxicology and Pharmacology, HelmholtzZentrum München, Neuherberg, Bavaria, Germany
| | - Bettina Lorenz-Depiereux
- German Research Center for Environmental Health, Institute of Human Genetics, HelmholtzZentrum München, Neuherberg, Bavaria, Germany
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23
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Abstract
Fibroblast growth factor 23 (FGF23) has emerged as an important regulator of phosphate and vitamin D homeostasis. It is important to understand how FGF23 interacts with vitamin D and parathyroid hormone (PTH) in a FGF23-Vitamin D-PTH axis to regulate mineral homeostasis. In this review, we discuss the genomic structure, and transcriptional, translational, and posttranslational regulation of FGF23. We describe its interaction with PTH and vitamin D, disorders of altered FGF23 states, and emerging therapies for diseases of FGF23 based upon these findings. This discussion helps redefine the role of PTH and vitamin D in relation to a complex bone-kidney-parathyroid loop, and points to areas within this complicated field in need of further clarification and research.
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Affiliation(s)
- Jenny E Blau
- Program of Reproductive and Adult Endocrinology, National Institute of Child Health and Human Development (NICHD), National Institutes of Health, Bethesda, MD, 20892, USA
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24
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A unified model for bone-renal mineral and energy metabolism. Curr Opin Pharmacol 2015; 22:64-71. [PMID: 25880364 DOI: 10.1016/j.coph.2015.03.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 03/27/2015] [Accepted: 03/30/2015] [Indexed: 01/09/2023]
Abstract
The beginning of the millennium saw the discovery of a new bone-matrix protein, Matrix Extracellular PhosphoglycoprotEin (MEPE) and an associated C-terminal motif called ASARM. This motif and other distinguishing features occur in a group of proteins called SIBLINGs. These proteins include dentin matrix protein 1 (DMP1), osteopontin, dentin-sialophosphoprotein (DSPP), statherin, bone sialoprotein (BSP) and MEPE. MEPE, DMP1 and ASARM-motifs regulate expression of a phosphate regulating cytokine FGF23. Further, a trimeric interaction between phosphate regulating endopeptidase homolog X-linked (PHEX), DMP1, and α5β3-integrin that occurs on the plasma-membrane of the osteocyte mediates FGF23 regulation (FAP pathway). ASARM-peptides competitively inhibit the trimeric complex and increase FGF23. A second pathway involves specialized structures, matrix vesicles pathway (MVP). This review will discuss the FAP and MVP pathways and present a unified model for mineral and energy metabolism.
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25
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Lin N, Li J, Lu Z, Bian L, Zheng L, Cao Q, Ding Z. A turn-on coordination nanoparticle-based fluorescent probe for phosphate in human serum. NANOSCALE 2015; 7:4971-4977. [PMID: 25690475 DOI: 10.1039/c5nr00515a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Coordination nanoparticles (CNPs) are becoming attractive platforms for chemical sensing applications because their unique adjustable properties offer the opportunity to design various luminescent nanoprobes. Here, we present a CNP-based fluorescent nanoprobe, in which fluorophores (rhodamine B, RB) and quenchers (methylene blue, MB) were spontaneously enfolded by coordination networks self-assembled of adenine, biphenyl-4,4'-dicarboxylic acid (BDA) and zinc ions. The aggregation of fluorophores and quenchers in CNPs resulted in a quenched state fluorescence of RB. RB and MB could be released from CNPs in the presence of phosphate, which triggered the fluorescence of RB. On the basis of recognition-driven disassembly principle, a novel turn-on fluorescent probe for the determination of PO4(3-) with a wide response range (0.5-50 μM) has been successfully applied in the detection of phosphate in human serum samples. This work not only develops a probe for phosphate but also provides a general strategy for designing nanoprobes or nanocarriers towards various targets by altering organic linkers or metal ions.
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Affiliation(s)
- Na Lin
- Key Laboratory of Medicinal Chemistry for Natural Resource (Yunnan University), Ministry of Education, School of Chemical Science and Technology, Yunnan University, Kunming, Yunnan 650091, China.
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26
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Abstract
Phosphate is essential for growth and maintenance of the skeleton and for generating high-energy phosphate compounds. Evolutionary adaptation to high dietary phosphorous in humans and other terrestrial vertebrates involves regulated mechanisms assuring the efficient renal elimination of excess phosphate. These mechanisms prominently include PTH, FGF23, and Vitamin D, which directly and indirectly regulate phosphate transport. Disordered phosphate homeostasis is associated with pathologies ranging from kidney stones to kidney failure. Chronic kidney disease results in hyperphosphatemia, an elevated calcium×phosphate product with considerable morbidity and mortality, mostly associated with adverse cardiovascular events. This chapter highlights recent findings and insights regarding the hormonal regulation of renal phosphate transport along with imbalances of phosphate balance due to acquired or inherited diseases states.
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27
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Abstract
The Klotho family consists of three single-pass transmembrane proteins—αKlotho, βKlotho and γKlotho. Each of them combines with fibroblast growth factor (FGF) receptors (FGFRs) to form receptor complexes for various FGF’s. αKlotho is a co-receptor for physiological FGF23 signaling and appears essential for FGF23-mediated regulation of mineral metabolism. αKlotho protein also plays a FGF23-independent role in phosphate homeostasis. Animal experimental studies and clinical observations have demonstrated that αKlotho deficiency leads to severe hyperphosphatemia; moderate elevation of αKlotho reduces serum phosphate and extremely high αKlotho induces hypophosphatemia and high-FGF23. αKlotho maintains circulating phosphate in a narrow range by modulating intestinal phosphate absorption, urinary phosphate excretion by the kidney, and phosphate distribution into bone rather than soft tissue in concerted interaction with other calciophosphotropic hormones such as PTH, FGF23, and 1,25-(OH)2 vitamin D. The role of αKlotho in maintenance of phosphate homeostasis is mediated by direct suppression of Na-dependent phosphate cotransporters in target organs. Therefore, αKlotho manipulation may be a novel strategy for genetic and acquired phosphate disorders and for medical conditions with αKlotho deficiency such as chronic kidney disease in future.
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Affiliation(s)
- Ao Bian
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas
- Department of Nephrology, First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, PR of China
| | - Changying Xing
- Department of Nephrology, First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, PR of China
| | - Ming Chang Hu
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
- Corresponding author: Ming Chang Hu, M.D.; Ph.D., Department of Internal Medicine, Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390-885 USA, Telephone: 1-214-648-9797, Tax: 1-214-648-5652,
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Takeyari S, Yamamoto T, Kinoshita Y, Fukumoto S, Glorieux FH, Michigami T, Hasegawa K, Kitaoka T, Kubota T, Imanishi Y, Shimotsuji T, Ozono K. Hypophosphatemic osteomalacia and bone sclerosis caused by a novel homozygous mutation of the FAM20C gene in an elderly man with a mild variant of Raine syndrome. Bone 2014; 67:56-62. [PMID: 24982027 DOI: 10.1016/j.bone.2014.06.026] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Revised: 06/19/2014] [Accepted: 06/20/2014] [Indexed: 01/02/2023]
Abstract
BACKGROUND Hypophosphatemia and increased serum fibroblast growth factor 23 (FGF23) levels have been reported in young brothers with compound heterozygous mutations for the FAM20C gene; however, rickets was not observed in these cases. We report an adult case of Raine syndrome accompanying hypophosphatemic osteomalacia with a homozygous FAM20C mutation (R408W) associated with increased periosteal bone formation in the long bones and an increase in bone mineral density in the femoral neck. CASE The patient, a 61-year-old man, was born from a cousin-to-cousin marriage. A short stature and severe dental demineralization were reported at an elementary school age. Hypophosphatemia was noted inadvertently at 27years old, at which time he started to take an active vitamin D metabolite (alphacalcidol) and phosphate. He also manifested ossification of the posterior longitudinal ligament. On bone biopsy performed at the age of 41years, we found severe osteomalacia surrounding osteocytes, which appeared to be an advanced form of periosteocytic hypomineralized lesions compared to those reported in patients with X-linked hypophosphatemic rickets. Laboratory data at 61years of age revealed markedly increased serum intact-FGF23 levels, which were likely to be the cause of hypophosphatemia and the decreased level of 1,25(OH)2D. We recently identified a homozygous FAM20C mutation, which was R408W, in this patient. When expressed in HEK293 cells, the R408W mutant protein exhibited impaired kinase activity and secretion. DISCUSSION Our findings suggest that certain homozygous FAM20C mutations can cause FGF23-related hypophosphatemic osteomalacia and indicate the multiple roles of FAM20C in bone.
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Affiliation(s)
- Shinji Takeyari
- Department of Pediatrics, Minoh City Hospital, Osaka 562-8562, Japan
| | - Takehisa Yamamoto
- Department of Pediatrics, Minoh City Hospital, Osaka 562-8562, Japan.
| | - Yuka Kinoshita
- Division of Nephrology and Endocrinology, Department of Medicine, The University of Tokyo Hospital, Tokyo 113-8655, Japan
| | - Seiji Fukumoto
- Division of Nephrology and Endocrinology, Department of Medicine, The University of Tokyo Hospital, Tokyo 113-8655, Japan
| | - Francis H Glorieux
- Genetics Unit, Shriners Hospitals for Children, Montreal H3G 1A6, Canada
| | - Toshimi Michigami
- Department of Bone and Mineral Research, Osaka Medical Center and Research Institute for Maternal and Child Health, Osaka 594-1011, Japan
| | - Kosei Hasegawa
- Department of Pediatrics, Okayama University Hospital, Okayama 700-8558, Japan
| | - Taichi Kitaoka
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
| | - Takuo Kubota
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
| | - Yasuo Imanishi
- Department of Metabolism, Endocrinology and Molecular Medicine, Osaka City University Graduate School of Medicine, Osaka 545-8585, Japan
| | | | - Keiichi Ozono
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
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Abstract
PURPOSE OF REVIEW Inherited disorders of calcium and phosphate homeostasis have variable presentation and can cause significant morbidity. An understanding of the mode of inheritance and pathophysiology of these conditions will help in the diagnosis and early institution of therapy. RECENT FINDINGS Identification of genetic mutations in humans and animal models has advanced our understanding of many inherited disorders of calcium and phosphate regulation. Identification of mutations of calcium-sensing receptor has improved our understanding of hypocalcemic and hypercalcemic conditions. Mutations of Fgf23, Klotho and phosphate transporter genes have been identified to cause disorders of phosphate metabolism. SUMMARY Calcium and phosphate homeostasis is tightly regulated in a narrow range due to their vital role in many biological processes. Inherited disorders of calcium and phosphate metabolism though uncommon can have severe morbidity. Genetic counseling of the affected families is an important part of the follow-up of these patients.
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30
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Huang X, Jiang Y, Xia W. FGF23 and Phosphate Wasting Disorders. Bone Res 2013; 1:120-32. [PMID: 26273497 DOI: 10.4248/br201302002] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 04/25/2013] [Indexed: 11/10/2022] Open
Abstract
A decade ago, only two hormones, parathyroid hormone and 1,25(OH)2D, were widely recognized to directly affect phosphate homeostasis. Since the discovery of fibroblast growth factor 23 (FGF23) in 2000 (1), our understanding of the mechanisms of phosphate homeostasis and of bone mineralization has grown exponentially. FGF23 is the link between intestine, bone, and kidney together in phosphate regulation. However, we still do not know the complex mechanism of phosphate homeostasis and bone mineralization. The physiological role of FGF23 is to regulate serum phosphate. Secreted mainly by osteocytes and osteoblasts in the skeleton (2,3), it modulates kidney handling of phosphate reabsorption and calcitriol production. Genetic and acquired abnormalities in FGF23 structure and metabolism cause conditions of either hyper-FGF23 or hypo-FGF23. Hyper-FGF23 is related to hypophosphatemia, while hypo-FGF23 is related to hyperphosphatemia. Both hyper-FGF23 and hypo-FGF23 are detrimental to humans. In this review, we will discuss the pathophysiology of FGF23 and hyper-FGF23 related renal phosphate wasting disorders (4).
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Affiliation(s)
- Xianglan Huang
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences , Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing 100730, China
| | - Yan Jiang
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences , Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing 100730, China
| | - Weibo Xia
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences , Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing 100730, China
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31
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Abstract
Recently, fibroblast growth factor 23 (FGF23) has sparked widespread interest because of its potential role in regulating phosphate and vitamin D metabolism. In this review, we summarized the FGF superfamily, the mechanism of FGF23 on phosphate and vitamin D metabolism, and the FGF23 related bone disease.
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Affiliation(s)
- Eryuan Liao
- Institute of Metabolism and Endocrinology, the Second Xiangya Hospital, Central South University, Changsha, 410011, China.
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Seton M, Jüppner H. Autosomal dominant hypophosphatemic rickets in an 85 year old woman: characterization of her disease from infancy through adulthood. Bone 2013; 52:640-3. [PMID: 23174215 PMCID: PMC5103613 DOI: 10.1016/j.bone.2012.11.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Revised: 11/06/2012] [Accepted: 11/08/2012] [Indexed: 01/23/2023]
Abstract
BACKGROUND Autosomal dominant hypophosphatemic rickets (ADHR) is a rare genetic disorder of phosphate homeostasis characterized, when severely expressed, by osteomalacia, suppressed levels of calcitriol, and renal phosphate wasting due to elevated levels of fibroblast growth factor 23 (FGF23). The disease is caused by heterozygous FGF23 mutations at the RXXR site that prevent cleavage of the intact hormone. OBJECTIVES An FGF23 mutation was identified in the proband an 85-year-old woman with elevated FGF23 levels, and her clinical course was characterized. Medical records revealed she was treated for rickets as an infant. She was then asymptomatic until soon after her 4th pregnancy, when she suffered incapacitating bone pain and weakness, age 37. Symptoms remitted with brief treatment. RESULTS The proband and one son, but not other family members, were found to be heterozygous for the R176Q mutation in FGF23. Expression of this germ line mutation was strikingly different in both individuals in terms of skeletal health, FGF23 levels and disease activity. CONCLUSIONS The identified FGF23 mutation in two members of this family raises questions about molecular mechanisms that have led to intermittent increases in FGF23 synthesis and secretion, and disease expression.
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Affiliation(s)
- Margaret Seton
- Massachusetts General Hospital, Rheumatology, Allergy & Immunology, Bulfinch 165, 55 Fruit St, Boston, MA 02114, USA
- Corresponding author. Fax: +1 617 726 2872
| | - Harald Jüppner
- Massachusetts General Hospital, Endocrine Unit, Thier 10, 55 Fruit St, Boston, MA 02114, USA
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Renal phosphate handling in Gitelman syndrome--the results of a case-control study. Pediatr Nephrol 2013; 28:65-70. [PMID: 22990302 DOI: 10.1007/s00467-012-2297-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Revised: 08/08/2012] [Accepted: 08/09/2012] [Indexed: 10/27/2022]
Abstract
BACKGROUND Patients with Gitelman syndrome, a hereditary salt-wasting tubulopathy, have loss-of-function mutations in the SLC12A3 gene coding for the thiazide-sensitive sodium chloride co-transporter in the distal convoluted tubule. Since the bulk of filtered phosphate is reabsorbed in the proximal tubule, renal phosphate wasting is considered exceptional in Gitelman syndrome. METHODS We investigated the renal handling of inorganic phosphate in 12 unselected Italian patients affected with Gitelman syndrome (5 females and 7 males, aged 6.0-18 years, median age 12 years) and in 12 healthy subjects matched for gender and age (controls). The diagnosis of Gitelman syndrome among the patients had been made clinically and confirmed by molecular biology studies. RESULTS The biochemical hallmarks of Gitelman syndrome, namely hypochloremia, hypokalemia, hypomagnesemia, increased urinary excretion of sodium, chloride, potassium and magnesium and reduced urinary excretion of calcium, were present in the 12 patients. In addition, both the plasma inorganic phosphate concentration (median and interquartile range: 1.28 [1.12-1.36] vs. 1.61 [1.51-1.66)] mmol/L) and the maximal tubular reabsorption of inorganic phosphate (1.08 [0.99-1.22] vs. 1.41 [1.38-1.47] mmol/L) were significantly lower (P < 0.001) in Gitelman patients than in control subjects. Circulating levels of 25-hydroxyvitamin D, intact parathyroid hormone and osteocalcin were similar in patients and controls. CONCLUSIONS The results of our case-control study disclose a hitherto unrecognized tendency towards renal phosphate wasting with mild to moderate hypophosphatemia in Gitelman syndrome.
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Abstract
PURPOSE OF REVIEW Description of the recent advances on the regulation of phosphate metabolism, gene mutations, and new approaches to treatment in patients with hypophosphatemic rickets. RECENT FINDINGS Fibroblast growth factor 23 (FGF23) overproduction may be a primary cause of hypophosphatemic rickets. Inactivating mutations of phosphate-regulating gene with homologies to endopeptidases on the X chromosome, dentin matrix acidic phosphoprotein 1, and ectonucleotide pyrophosphatase/phosphodiesterase 1 are associated with X-linked hypophosphatemic rickets, autosomal recessive hypophosphatemic rickets 1, and autosomal recessive hypophosphatemic rickets 2, respectively. Activating mutations of FGF23 gene is the cause of autosomal dominant hypophosphatemic rickets. Iron deficiency may affect autosomal dominant hypophosphatemic rickets phenotype by regulating FGF23 production.Current treatment with activated vitamin D metabolites and oral inorganic phosphate salts may partially correct skeletal lesions and linear growth in patients with hypophosphatemic rickets. However, some patients have poor improvement by the current treatment. SUMMARY Identification of the causative mutation in patients with hypophosphatemic rickets may be useful to confirm the diagnosis and probably for prognosis. Inhibition of FGF23 overproduction by anti-FGF23 neutralizing antibodies could be a future approach for treatment of patients with FGF23-dependent hypophosphatemic rickets.
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Affiliation(s)
- Giampiero I Baroncelli
- Pediatric Unit I, Department of Obstetrics, Gynecology and Pediatrics, University-Hospital, Pisa, Italy.
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Ladenhauf HN, Stundner O, Spreitzhofer F, Deluggi S. Severe hyperphosphatemia after administration of sodium-phosphate containing laxatives in children: case series and systematic review of literature. Pediatr Surg Int 2012; 28:805-14. [PMID: 22820833 DOI: 10.1007/s00383-012-3124-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
INTRODUCTION Sodium phosphate-containing laxatives are commonly used as first-line treatment option for constipation in children and adolescents. Hyperphosphatemia is an infrequent, but potentially life-threatening complication of laxative application. METHODS We report a case series of three children exhibiting severe hyperphosphatemia and hypocalcemia after utilization of sodium phosphate-containing laxatives, necessitating intensive care services in two of three cases. Additionally, we reviewed 32 case reports of similar occurrences. RESULTS We identified 28 publications on the subject dating from 1968 to 2010. Mean age of all children in reports was 2.83 years; sex was approximately equally distributed. While 18 patients suffered from either pre-existing gastrointestinal comorbidity or other major systemic disease, no or only unrelated, minor conditions were present in ten children. One-third of patients received laxatives repeatedly before the incident. Findings associated with hyperphosphatemia include lethargy, dizziness, stiffness, tachypnea, tachycardia and severe dehydration in almost all cases, and tetany, carpopedal spasm, and prolonged QT interval in a subset. While about 80% of children recovered without residual findings, three deceased and one incurred persistent hypoxic brain damage. CONCLUSION Physicians should be alerted to the possibility of phosphate toxicity in children and adolescents treated with laxatives.
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Affiliation(s)
- Hannah N Ladenhauf
- Department of Pediatric and Adolescent Surgery, University Hospital Salzburg, Muellner Hauptstrasse 48, 5020, Salzburg, Austria.
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