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Li C, Azad MAK, Zhu Q, Cheng Y, Gui J, Song B, Zhou Z, Kong X. Differences in intestinal and renal Ca and P uptake in three different breeds of growing-finishing pigs. Vet Q 2024; 44:1-16. [PMID: 38965863 PMCID: PMC11229737 DOI: 10.1080/01652176.2024.2371609] [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: 11/06/2023] [Accepted: 06/17/2024] [Indexed: 07/06/2024] Open
Abstract
This study investigated the differences in bone growth and turnover and calcium (Ca) and phosphorus (P) uptake among three different breeds of growing-finishing pigs. Ninety healthy Duroc, Xiangcun black (XCB), and Taoyuan black (TYB) pigs (30 pigs per breed) at 35 day-old (D) with the average body weight (BW) of their respective breed were assigned and raised to 185 D. The results showed that Duroc pigs had higher bone weight and length than the XCB and TYB pigs at 80, 125, and 185 D and the bone index at 185 D (p < 0.05). Duroc pigs had higher bone mineral densities (femur and tibia) compared with the other two breeds at 80 D and 125 D, whereas TYB pigs had higher mineral content and bone breaking load (rib) compared with the other two breeds at 185 D (p < 0.05). The bone morphogenetic protein-2 and osteocalcin concentrations were higher, and TRACP5b concentration was lower in serum of TYB pigs at 125 D (p < 0.05). Meanwhile, 1,25-dihydroxyvitamin D3, parathyroid hormone, thyroxine, and fibroblast growth factor 23 concentrations were higher in serum of TYB pigs at 185 D (p < 0.05). The TYB pigs had higher apparent total tract digestibility of P at 80 D and 185 D and bone Ca and P contents at 185 D in comparison to the Duroc pigs (p < 0.05). Furthermore, gene expressions related to renal uptake of Ca and P differed among the three breeds of pigs. Collectively, Duroc pigs have higher bone growth, whereas TYB pigs have a higher potential for mineral deposition caused by more active Ca uptake.
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Affiliation(s)
- Chenjian Li
- CAS Key Laboratory of Agro-ecological Processes in Subtropical Region, Hunan Provincial Key Laboratory of Animal Nutritional Physiology and Metabolic Process, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China
- College of Veterinary Medicine, Nanjing Agriculture University, Nanjing, Jiangsu, China
| | - Md. Abul Kalam Azad
- CAS Key Laboratory of Agro-ecological Processes in Subtropical Region, Hunan Provincial Key Laboratory of Animal Nutritional Physiology and Metabolic Process, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Qian Zhu
- CAS Key Laboratory of Agro-ecological Processes in Subtropical Region, Hunan Provincial Key Laboratory of Animal Nutritional Physiology and Metabolic Process, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Yating Cheng
- CAS Key Laboratory of Agro-ecological Processes in Subtropical Region, Hunan Provincial Key Laboratory of Animal Nutritional Physiology and Metabolic Process, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China
| | - Jue Gui
- CAS Key Laboratory of Agro-ecological Processes in Subtropical Region, Hunan Provincial Key Laboratory of Animal Nutritional Physiology and Metabolic Process, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Bo Song
- CAS Key Laboratory of Agro-ecological Processes in Subtropical Region, Hunan Provincial Key Laboratory of Animal Nutritional Physiology and Metabolic Process, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Zhenlei Zhou
- College of Veterinary Medicine, Nanjing Agriculture University, Nanjing, Jiangsu, China
| | - Xiangfeng Kong
- CAS Key Laboratory of Agro-ecological Processes in Subtropical Region, Hunan Provincial Key Laboratory of Animal Nutritional Physiology and Metabolic Process, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, Hunan, China
- College of Veterinary Medicine, Nanjing Agriculture University, Nanjing, Jiangsu, China
- College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, China
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Gong CY, Liu G, Shi HP, Liu S, Gao XY, Zhang SJ, Liu H, Li R, Wan D. Assessment of Non-Phytate Phosphorus Requirements of Chinese Jing Tint 6 Layer Chicks from Hatch to Day 42. Animals (Basel) 2024; 14:2093. [PMID: 39061555 PMCID: PMC11273798 DOI: 10.3390/ani14142093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2024] [Revised: 07/11/2024] [Accepted: 07/11/2024] [Indexed: 07/28/2024] Open
Abstract
We aimed to estimate the non-phytate phosphorus (NPP) requirements of Chinese Jing Tint 6 layer chicks. We randomly allocated 720 birds to five treatments with six cages of 24 birds each, feeding them a corn-soybean diet containing 0.36%, 0.41%, 0.46%, 0.51%, and 0.56% NNP. The results showed that the body weight gain (BWG), tibial length, and apparent total tract digestibility coefficients (ATTDC) of P were affected (p < 0.05) by dietary NPP level. A quadratic broken-line analysis (p < 0.05) of BWG indicated that the optimal NPP for birds aged 1-14 d was 0.411%. Similarly, 0.409% of NPP met tibial growth needs. However, 0.394% of NPP was optimal for P utilization according to the ATTDC criterion. For 15-42 d birds, 0.466% NPP, as estimated by the BWG criterion, was sufficient for optimal growth without decreasing P utilization. Using the factorial method, NPP requirements were calculated as 0.367% and 0.439%, based on the maintenance factors and BWG for 1-14 and 15-42 d birds, respectively, to maintain normal growth. Combining the non-linear model with the factorial method, this study recommends dietary NPP levels of 0.367% and 0.439% for 1-14 and 15-42 d birds, respectively, to optimize P utilization without affecting performance.
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Affiliation(s)
- Cheng-Yan Gong
- Laboratory of Animal Nutritional Physiology and Metabolic Process, Key Laboratory of Agroecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China; (C.-Y.G.); (S.L.); (X.-Y.G.); (S.-J.Z.); (H.L.)
- University of Chinese Academy of Sciences, Beijing 101408, China;
| | - Guang Liu
- Hubei Hongshan Laboratory, College of Animal Science and Technology, Huazhong Agricultural University, Wuhan 430070, China;
| | - Hong-Peng Shi
- University of Chinese Academy of Sciences, Beijing 101408, China;
| | - Shuan Liu
- Laboratory of Animal Nutritional Physiology and Metabolic Process, Key Laboratory of Agroecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China; (C.-Y.G.); (S.L.); (X.-Y.G.); (S.-J.Z.); (H.L.)
- University of Chinese Academy of Sciences, Beijing 101408, China;
| | - Xin-Yi Gao
- Laboratory of Animal Nutritional Physiology and Metabolic Process, Key Laboratory of Agroecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China; (C.-Y.G.); (S.L.); (X.-Y.G.); (S.-J.Z.); (H.L.)
| | - Shou-Jun Zhang
- Laboratory of Animal Nutritional Physiology and Metabolic Process, Key Laboratory of Agroecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China; (C.-Y.G.); (S.L.); (X.-Y.G.); (S.-J.Z.); (H.L.)
| | - Hao Liu
- Laboratory of Animal Nutritional Physiology and Metabolic Process, Key Laboratory of Agroecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China; (C.-Y.G.); (S.L.); (X.-Y.G.); (S.-J.Z.); (H.L.)
| | - Rui Li
- Laboratory of Animal Nutritional Physiology and Metabolic Process, Key Laboratory of Agroecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China; (C.-Y.G.); (S.L.); (X.-Y.G.); (S.-J.Z.); (H.L.)
| | - Dan Wan
- Laboratory of Animal Nutritional Physiology and Metabolic Process, Key Laboratory of Agroecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China; (C.-Y.G.); (S.L.); (X.-Y.G.); (S.-J.Z.); (H.L.)
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Lucea S, Chopo-Escuin G, Guillén N, Sosa C, Sorribas V. Intestinal and Renal Adaptations to Changes of Dietary Phosphate Concentrations in Rat. FUNCTION 2023; 5:zqad063. [PMID: 38033458 PMCID: PMC10686248 DOI: 10.1093/function/zqad063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 11/05/2023] [Accepted: 11/07/2023] [Indexed: 12/02/2023] Open
Abstract
We have studied the role of the intestine, kidney, and several hormones when adapting to changes in dietary P concentration. Normal and parathyroidectomized (PTX) rats were fed pH-matched diets containing 0.1%, 0.6%, and 1.2% P concentrations. 32Pi uptake was determined in the jejunum and kidney cortex brush border membrane vesicles. Several hormone and ion concentrations were determined in the blood and urine of rats. Both jejunum and kidney cortex Pi transport was regulated with 5 d of chronic feeding of P diets in normal rats. Acute adaptation was determined by switching foods on day 6, which was only clearly observed in the kidney cortex of normal rats, with more statistical variability in the jejunum. However, no paradoxical increase of Pi uptake in the jejunum was reproduced after the acute switch to the 1.2% P diet. Pi uptake in the jejunum was parathyroid hormone (PTH)-independent, but in the kidney, the chronic adaptation was reduced, and no acute dietary adaptations were observed. The NaPi2a protein was more abundant in the PTX than the sham kidneys, but contrary to the modest or absent changes in Pi uptake adaptation, the transporter was similarly regulated by dietary P, as in the sham rats. PTH and fibroblast growth factor 23 (FGF23) were the only hormones regulated by all diet changes, even in fasting animals, which exhibited regulated Pi transport despite similar phosphatemia. Evidence of Pi appetite effects was also observed. In brief, our results show new characteristics of Pi adaptations, including a lack of correlation between Pi transport, NaPi2a expression, and PTH/FGF23 concentrations.
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Affiliation(s)
- Susana Lucea
- Laboratory of Molecular Toxicology, Department of Biochemistry and Cell and Molecular Biology, University of Zaragoza, E50013 Zaragoza, Spain
| | - Gema Chopo-Escuin
- Laboratory of Molecular Toxicology, Department of Biochemistry and Cell and Molecular Biology, University of Zaragoza, E50013 Zaragoza, Spain
| | - Natalia Guillén
- Laboratory of Molecular Toxicology, Department of Biochemistry and Cell and Molecular Biology, University of Zaragoza, E50013 Zaragoza, Spain
| | - Cecilia Sosa
- Laboratory of Molecular Toxicology, Department of Biochemistry and Cell and Molecular Biology, University of Zaragoza, E50013 Zaragoza, Spain
| | - Víctor Sorribas
- Laboratory of Molecular Toxicology, Department of Biochemistry and Cell and Molecular Biology, University of Zaragoza, E50013 Zaragoza, Spain
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Yasuda S, Inoue K, Matsui I, Matsumoto A, Katsuma Y, Okushima H, Imai A, Sakaguchi Y, Kaimori JY, Yamamoto R, Mizui M, Isaka Y. Hepatic phosphate uptake and subsequent nerve-mediated phosphaturia are crucial for phosphate homeostasis following portal vein passage of phosphate in rats. Sci Rep 2023; 13:5794. [PMID: 37031318 PMCID: PMC10082792 DOI: 10.1038/s41598-023-32856-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 04/03/2023] [Indexed: 04/10/2023] Open
Abstract
Fibroblast growth factor 23, parathyroid hormone, and 1,25-dihydroxyvitamin D are critical in phosphate homeostasis. Despite these factors' importance, regulators of phosphaturia in the acute postprandial phase remain largely unknown. This study investigated the mechanism of acute phosphate regulation in the postprandial phase in rats. Duodenal administration of radiolabeled phosphate (32P) showed that 32P levels in the inferior vena cava (IVC) blood were lower than those in the portal vein (PV) blood. Serum phosphate concentration transiently increased 5 min after phosphate solution administration through IVC, while it was maintained after the administration through PV. Phosphate administration through both IVC and PV resulted in increased fractional excretion of phosphate (FEPi) at 10 min without elevation of the known circulating factors, but urinary phosphate excretion during the period was 8% of the dose. Experiments using 32P or partial hepatectomy showed that the liver was one of the phosphate reservoirs. The elevation of FEPi and suppression of sodium-phosphate cotransporter 2a in the kidney at 10 min was attenuated in rats with SCH23390, hepatic denervation, or renal denervation, thus indicating that the liver communicated with the kidney via the nervous system to promote phosphaturia. These results revealed previously unknown mechanisms for serum phosphate maintenance.
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Affiliation(s)
- Seiichi Yasuda
- Department of Nephrology, Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Suita, Osaka, 565-0871, Japan
| | - Kazunori Inoue
- Department of Nephrology, Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Suita, Osaka, 565-0871, Japan
| | - Isao Matsui
- Department of Nephrology, Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Suita, Osaka, 565-0871, Japan.
- Transdimensional Life Imaging Division, Institute for Open and Transdisciplinary Research Initiatives, Osaka University, 2-1 Yamada-oka, Suita, Osaka, 565-0871, Japan.
| | - Ayumi Matsumoto
- Department of Nephrology, Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Suita, Osaka, 565-0871, Japan
| | - Yusuke Katsuma
- Department of Nephrology, Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Suita, Osaka, 565-0871, Japan
| | - Hiroki Okushima
- Department of Nephrology, Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Suita, Osaka, 565-0871, Japan
| | - Atsuhiro Imai
- Department of Nephrology, Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Suita, Osaka, 565-0871, Japan
| | - Yusuke Sakaguchi
- Department of Inter-Organ Communication Research in Kidney Disease, Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Suita, Osaka, 565-0871, Japan
| | - Jun-Ya Kaimori
- Department of Inter-Organ Communication Research in Kidney Disease, Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Suita, Osaka, 565-0871, Japan
| | - Ryohei Yamamoto
- Department of Nephrology, Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Suita, Osaka, 565-0871, Japan
- Health Promotion and Regulation, Department of Health Promotion Medicine, Osaka University Graduate School of Medicine, 1-17 Machikaneyamacho, Toyonaka, Osaka, 560-0043, Japan
- Health and Counseling Center, Osaka University, 1-17 Machikaneyamacho, Toyonaka, Osaka, 560-0043, Japan
| | - Masayuki Mizui
- Department of Nephrology, Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Suita, Osaka, 565-0871, Japan
| | - Yoshitaka Isaka
- Department of Nephrology, Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Suita, Osaka, 565-0871, Japan
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Turner ME, Paynter AS, White CA, Mazzetti T, Ward EC, Norman PA, Munroe J, Adams MA, Holden RM. Sex Differences in Phosphate Homeostasis: Females Excrete More Phosphate and Calcium After an Oral Phosphate Challenge. J Clin Endocrinol Metab 2023; 108:909-919. [PMID: 36268820 DOI: 10.1210/clinem/dgac616] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 09/14/2022] [Indexed: 11/19/2022]
Abstract
CONTEXT Dietary consumption of phosphate is increasing, and elevated serum phosphate is associated with increased cardiovascular disease (CVD) risk. Sex differences in phosphate homeostasis and response to changes in dietary phosphate intake, which are not captured by clinically measured analytes, may contribute to differences in CVD presentation and bone disease. OBJECTIVE To assess sex differences in acute phosphate homeostasis in response to a single oral phosphate challenge. DESIGN Cross-sectional. SETTING General community. PARTICIPANTS 78 participants (40-76 years) with measured glomerular filtration rate >60 mL/min/1.73 m2 and no clinically diagnosed CVD and 14 young healthy adults. MAIN OUTCOME MEASURES To elucidate subtle alterations in phosphate homeostasis, we employ an acute challenge whereby the hormonal response, circulating mineral levels, and urinary excretion are assessed following an oral challenge of phosphate. RESULTS Although both males and females had similar changes in circulating phosphate, calcium, and parathyroid hormone in response to the challenge, females excreted ∼1.9x more phosphate and ∼2.7x more calcium than males, despite not consuming calcium. These sex differences were recapitulated in healthy young adults. This excretion response did not correlate to age, serum phosphate, or estradiol levels. The females with greater excretion of phosphate had higher levels of bone resorption markers compared to formation markers. CONCLUSIONS Taken together, these data identify sex differences in acute phosphate homeostasis, specifically that females may mobilize and excrete endogenous sources of calcium and phosphate in response to oral phosphate compared to males. While high levels of dietary phosphate negatively impact bone, our results suggest that females may incur more risk from these diets.
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Affiliation(s)
- Mandy E Turner
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L3N6, Canada
| | - Amanda S Paynter
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L3N6, Canada
| | - Christine A White
- Department of Medicine, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Tom Mazzetti
- Department of Medicine, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Emilie C Ward
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L3N6, Canada
| | - Patrick A Norman
- KGH Research Institute, Kingston Health Sciences Centre, Kingston, ON K7L2V7, Canada
| | - Jenny Munroe
- Clinical Nutrition, Kingston Health Sciences Center, Kingston, ON K7L 2V7, Canada
| | - Michael A Adams
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L3N6, Canada
| | - Rachel M Holden
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L3N6, Canada
- Department of Medicine, Queen's University, Kingston, ON K7L 3N6, Canada
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Elevated Initial Serum Phosphate Levels Predict Higher Mortality and Impaired Neurological Outcome in Cardiac Arrest Patients with Return of Spontaneous Circulation. Diagnostics (Basel) 2023; 13:diagnostics13030479. [PMID: 36766585 PMCID: PMC9914872 DOI: 10.3390/diagnostics13030479] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 01/15/2023] [Accepted: 01/17/2023] [Indexed: 02/03/2023] Open
Abstract
Purpose: Although a moderate proportion of cardiac arrest (CA) patients achieve a return of spontaneous circulation (ROSC), few survive to discharge, mostly with poor neurological development. As serum phosphate levels were described as elevated after cardiopulmonary resuscitation (CPR), we asked whether these elevations would predict a higher risk of mortality and impaired neurological outcome in CA patients following ROSC. Methods: Initial serum phosphate levels, survival, and neurologic status at discharge of 488 non-traumatic CA patients treated at a single German hospital after achieving ROSC were analyzed. The cut-off value of phosphate for mortality prediction was determined using the receiver operator characteristic (ROC) curve, and patients were divided accordingly for comparison. Results were validated by analyzing phosphate levels in a multi-centric cohort containing 3299 CA patients from the eICU database of the United States. Results: In the German cohort, ROC analysis showed a 90% specificity for phosphate levels >2.7 mmol/L to predict mortality (AUC: 0.76, p < 0.0001), and phosphate level elevations were associated with higher in-hospital mortality (crude odds ratio 3.04, 95% CI 2.32 to 4.08). Patients with initial phosphate levels >2.7 mmol/L had significantly higher mortality in both analyzed collectives (p < 0.0001). Similarly, patients from the German cohort who initially had higher phosphate levels also showed a higher proportion of impaired neurological status at discharge and morphological signs of brain injury. Conclusions: In CA patients following ROSC, initial serum phosphate levels >2.7 mmol/L predict higher mortality and impaired neurological outcome. Our data suggests that phosphate determination might improve the preciseness of the overall and neurologic prognostication in patients after CPR following ROSC.
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Marques JVO, Moreira CA, Borba VZC. New treatments for rare bone diseases: hypophosphatemic rickets/osteomalacia. ARCHIVES OF ENDOCRINOLOGY AND METABOLISM 2022; 66:658-665. [PMID: 36382755 PMCID: PMC10118827 DOI: 10.20945/2359-3997000000555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Phosphorus is one of the most abundant minerals in the human body; it is required to maintain bone integrity and mineralization, in addition to other biological processes. Phosphorus is regulated by parathyroid hormone, 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], and fibroblast growth factor 23 (FGF-23) in a complex set of processes that occur in the gut, skeleton, and kidneys. Different molecular mechanisms - overproduction of FGF-23 by tumors responsible for oncogenic osteomalacia, generation of an FGF-23 mutant that is resistant to cleavage by enzymes, and impaired FGF-23 degradation due to a reduction in or loss of the PHEX gene - can lead to FGF-23-stimulating activity and the consequent waste of urinary phosphate and low levels of 1,25(OH)2D3. Conventional treatment consists of multiple daily doses of oral phosphate salts and vitamin D analogs, which may improve radiographic rickets but do not normalize growth. Complications of the conventional long-term treatment consist of hypercalcemia, hypercalciuria, nephrolithiasis, nephrocalcinosis, impaired renal function, and potentially chronic kidney disease. Recently, burosumab, an antibody against FGF-23, was approved as a novel therapy for children and adults with X-linked hypophosphatemia and patients with tumor-induced osteomalacia. Burosumab showed good performance in different trials in children and adults. It increased and sustained the serum phosphorus levels, decreased the rickets severity and pain scores, and improved mineralization. It offers a new perspective on the treatment of chronic and disabling diseases.
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Targeting choroid plexus epithelium as a novel therapeutic strategy for hydrocephalus. J Neuroinflammation 2022; 19:156. [PMID: 35715859 PMCID: PMC9205094 DOI: 10.1186/s12974-022-02500-3] [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: 11/27/2021] [Accepted: 06/01/2022] [Indexed: 11/25/2022] Open
Abstract
The choroid plexus is a tissue located in the lateral ventricles of the brain and is composed mainly of choroid plexus epithelium cells. The main function is currently thought to be the secretion of cerebrospinal fluid and the regulation of its pH, and more functions are gradually being demonstrated. Assistance in the removal of metabolic waste and participation in the apoptotic pathway are also the functions of choroid plexus. Besides, it helps to repair the brain by regulating the secretion of neuropeptides and the delivery of drugs. It is involved in the immune response to assist in the clearance of infections in the central nervous system. It is now believed that the choroid plexus is in an inflammatory state after damage to the brain. This state, along with changes in the cilia, is thought to be an abnormal physiological state of the choroid plexus, which in turn leads to abnormal conditions in cerebrospinal fluid and triggers hydrocephalus. This review describes the pathophysiological mechanism of hydrocephalus following choroid plexus epithelium cell abnormalities based on the normal physiological functions of choroid plexus epithelium cells, and analyzes the attempts and future developments of using choroid plexus epithelium cells as a therapeutic target for hydrocephalus.
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9
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Tsuboi Y, Ichida Y, Murai A, Maeda A, Iida M, Kato A, Ohtomo S, Horiba N. EOS789, pan-phosphate transporter inhibitor, ameliorates the progression of kidney injury in anti-GBM-induced glomerulonephritis rats. Pharmacol Res Perspect 2022; 10:e00973. [PMID: 35621227 PMCID: PMC9137114 DOI: 10.1002/prp2.973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 05/09/2022] [Indexed: 11/08/2022] Open
Abstract
Hyperphosphatemia associated with chronic kidney disease (CKD) not only dysregulates mineral metabolism and bone diseases, but also strongly contributes to the progression of kidney disease itself. We have identified a novel drug for hyperphosphatemia, EOS789, that interacts with several sodium-dependent phosphate transporters (NaPi-IIb, PiT-1, and PiT-2) known to contribute to intestinal phosphate absorption. In this study, we investigated whether EOS789 could ameliorate kidney disease progression in glomerulonephritis rats. Anti-glomerular basement membrane (GBM) nephritis was induced in rats by intravenously administering two types of anti-rat GBM antibodies. We evaluated the effect of EOS789 administered in food admixture on hyperphosphatemia and kidney disease progression. In an anti-GBM nephritis rats, which exhibit a significant increase in serum phosphate and a decline in renal function, EOS789 dose-dependently improved hyperphosphatemia and EOS789 at 0.3% food admixture significantly ameliorated kidney dysfunction as shown in the decline of serum creatinine and BUN. Renal histopathology analysis showed that EOS789 significantly decreased crescent formation in glomeruli. To elucidate the mechanism underlying glomerular disease progression, human mesangial cells were used. High phosphate concentration in media significantly increased the expression of Collagen 1A1, 3A1, and αSMA mRNA in human mesangial cells and EOS789 dose-dependently suppressed these fibrotic markers. These results indicate that EOS789 prevented glomerular crescent formation caused by mesangial fibrosis by ameliorating hyperphosphatemia. In conclusion, EOS789 would not only be useful against hyperphosphatemia but may also have the potential to relieve mesangial proliferative glomerulonephritis with crescent formation.
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Affiliation(s)
- Yoshinori Tsuboi
- Research DivisionChugai Pharmaceutical Co., Ltd.GotembaShizuokaJapan
| | - Yasuhiro Ichida
- Research DivisionChugai Pharmaceutical Co., Ltd.GotembaShizuokaJapan
| | - Atsuko Murai
- Translational Research DivisionChugai Pharmaceutical Co., Ltd.GotembaShizuokaJapan
| | - Akira Maeda
- Research DivisionChugai Pharmaceutical Co., Ltd.GotembaShizuokaJapan
| | - Manami Iida
- Research DivisionChugai Pharmaceutical Co., Ltd.GotembaShizuokaJapan
| | - Atsuhiko Kato
- Translational Research DivisionChugai Pharmaceutical Co., Ltd.GotembaShizuokaJapan
| | - Shuichi Ohtomo
- Translational Research DivisionChugai Pharmaceutical Co., Ltd.GotembaShizuokaJapan
| | - Naoshi Horiba
- Research DivisionChugai Pharmaceutical Co., Ltd.GotembaShizuokaJapan
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10
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Elliott J, Geddes RF. New concepts in phosphorus homeostasis and its impact on renal health with particular reference to the cat. Vet J 2022; 283-284:105842. [PMID: 35577278 DOI: 10.1016/j.tvjl.2022.105842] [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: 12/12/2021] [Revised: 05/08/2022] [Accepted: 05/10/2022] [Indexed: 11/17/2022]
Abstract
New discoveries relating to phosphorus homeostasis include the hormones fibroblast growth factor-23 and klotho produced by bone and kidney. These hormones, together with novel understanding of how calcium and phosphate ions are carried in colloidal form as calciprotein particles, have changed our view of how phosphorus is regulated. Recognition that high dietary intake of inorganic forms of phosphorus in humans is a risk factor for both cardiovascular and renal diseases have led to re-examination of the impact of inorganic sources of phosphorus in prepared cat foods on renal health. Data suggest that when homeostatic mechanisms lead to proximal tubular (S3 segment) phosphate concentrations exceeding 3.25mmol/L for a significant part of the day, tubular stress and structural kidney damage ensues. Recent experimental rodent studies support the concept that calciprotein particles form in the proximal tubule at these prevailing phosphate concentrations and trigger proximal tubular damage. Long-term feeding studies in cats suggest that carefully formulated prepared diets containing 1g/Mcal of inorganic phosphorus (in the form of sodium tripolyphosphate or potassium monophosphate and pyrophosphate), resulting in estimated tubular phosphate concentrations <2.5mmol/L can be fed to healthy adult cats without detectable adverse effects on renal health.
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Affiliation(s)
- Jonathan Elliott
- Department of Comparative Biomedical Sciences, Royal Veterinary College, Royal College Street, London NW1 0TU, UK.
| | - Rebecca F Geddes
- Department of Clinical Science and Services, Royal Veterinary College, Hawkshead Lane, Hatfield, Hertfordshire AL9 7TA, UK
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11
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Tanno H, Fujii T, Hirano K, Maeno S, Tonozuka T, Sakamoto M, Ohkuma M, Tochio T, Endo A. Characterization of fructooligosaccharide metabolism and fructooligosaccharide-degrading enzymes in human commensal butyrate producers. Gut Microbes 2022; 13:1-20. [PMID: 33439065 PMCID: PMC7833758 DOI: 10.1080/19490976.2020.1869503] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Butyrate produced by gut microbiota has multiple beneficial effects on host health, and oligosaccharides derived from host diets and glycans originating from host mucus are major sources of its production. A significant reduction of butyrate-producing bacteria has been reported in patients with inflammatory bowel diseases and colorectal cancers. Although gut butyrate levels are important for host health, oligosaccharide metabolic properties in butyrate producers are poorly characterized. We studied the metabolic properties of fructooligosaccharides (FOSs) and other prebiotic oligosaccharides (i.e. raffinose and xylooligosaccharides; XOSs) in gut butyrate producers. 1-Kestose (kestose) and nystose, FOSs with degrees of polymerization of 3 and 4, respectively, were also included. Fourteen species of butyrate producers were divided into four groups based on their oligosaccharide metabolic properties, which are group A (two species) metabolizing all oligosaccharides tested, group F (four species) metabolizing FOSs but not raffinose and XOSs, group XR (four species) metabolizing XOSs and/or raffinose but not FOSs, and group N (four species) metabolizing none of the oligosaccharides tested. Species assigned to groups A and XR are rich glycoside hydrolase (GH) holders, whereas those in groups F and N are the opposite. In total, 17 enzymes assigned to GH32 were observed in nine of the 14 butyrate producers tested, and species that metabolized FOSs had at least one active GH32 enzyme. The GH32 enzymes were divided into four clusters by phylogenetic analysis. Heterologous gene expression analysis revealed that the GH32 enzymes in each cluster had similar FOS degradation properties within clusters, which may be linked to the conservation/substitution of amino acids to bind with substrates in GH32 enzymes. This study provides important knowledge to understand the impact of FOS supplementation on the activation of gut butyrate producers. Abbreviations: SCFA, short chain fatty acid; FOS, fructooligosaccharide; XOS, xylooligosaccharide; CAZy, Carbohydrate Active Enzymes; CBM, carbohydrate-binding module; PUL, polysaccharide utilization locus; S6PH sucrose-6-phosphate hydrolase.
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Affiliation(s)
- Hiroki Tanno
- Department of Food, Aroma and Cosmetic Chemistry, Faculty of Bioindustry, Tokyo University of Agriculture, Hokkaido, Japan
| | | | | | - Shintaro Maeno
- Department of Food, Aroma and Cosmetic Chemistry, Faculty of Bioindustry, Tokyo University of Agriculture, Hokkaido, Japan
| | - Takashi Tonozuka
- Department of Applied Biological Science, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Mitsuo Sakamoto
- PRIME, Japan Agency for Medical Research and Development (AMED), Ibaraki, Japan,Microbe Division/Japan Collection of Microorganisms, RIKEN BioResource Research Center, Ibaraki, Japan
| | - Moriya Ohkuma
- Microbe Division/Japan Collection of Microorganisms, RIKEN BioResource Research Center, Ibaraki, Japan
| | | | - Akihito Endo
- Department of Food, Aroma and Cosmetic Chemistry, Faculty of Bioindustry, Tokyo University of Agriculture, Hokkaido, Japan,CONTACT Akihito Endo Department of Food, Aroma and Cosmetic Chemistry, Faculty of Bioindustry, Tokyo University of Agriculture, 196 Yasaka, Abashiri, Hokkaido099-2493, Japan
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12
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Brescia V, Fontana A, Lovero R, Capobianco C, Marsico SV, De Chirico T, Pinto C, Varraso L, Cazzolla AP, Di Serio F. Determination of iFGF23 Upper Reference Limits (URL) in healthy pediatric population, for its better correct use. Front Endocrinol (Lausanne) 2022; 13:1018523. [PMID: 36440231 PMCID: PMC9681906 DOI: 10.3389/fendo.2022.1018523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Accepted: 10/12/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The measurement of Fibroblast growth factor 23 (FGF23) may be useful in the diagnosis and management of abnormal phosphate metabolism in both patients with preserved renal function or with chronic kidney disease (CKD). FGF-23 tests differ considerably by molecule assayed (iFGF23 or cFGF23), analytical performance and reference ranges. We establish iFGF23 Upper Reference Limits (URL) in apparently healthy pediatric individuals using automated immunochemiluminescent assay. METHODS We measured the levels of plasma iFGF23 from 115 samples from apparently healthy pediatric subjects [59 (51.3%) individuals were male; median age 10 years (range 1-18)] included in an observational study conducted at Policlinico University Hospital of Bari. The method used for the iFGF23 assay was immunochemiluminescent sandwich assay developed by DiaSorin on the Liaison XL platform. Statistical calculation of 95% reference interval, right-sided (CLSI C28-A3) and verification of age and sex covariables was performed for the calculation of the URL. RESULTS The URL concentration of iFGF23 was 61.21 pg/mL (58.63 to 63.71, 90% CI). No significant differences were found between the median concentrations of iFGF23 differentiated by sex and age. CONCLUSIONS The dosage of iFGF23 is important both for the differential diagnosis of the various forms of rickets, and for the subsequent monitoring of the effectiveness of drug treatment. We have established the URL for the iFGF23 Liaison test in apparently healthy pediatric subjects. The availability of iFGF23 pediatric reference values will allow a better clinical use of the test.
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Affiliation(s)
- Vincenzo Brescia
- Clinical Pathology Unit, Azienda Ospedaliero-Universitaria (AOU) Policlinico Consorziale di Bari - Ospedale Giovanni XXIII, Bari, Italy
| | - Antonietta Fontana
- Clinical Pathology Unit, Azienda Ospedaliero-Universitaria (AOU) Policlinico Consorziale di Bari - Ospedale Giovanni XXIII, Bari, Italy
| | - Roberto Lovero
- Clinical Pathology Unit, Azienda Ospedaliero-Universitaria (AOU) Policlinico Consorziale di Bari - Ospedale Giovanni XXIII, Bari, Italy
- *Correspondence: Roberto Lovero,
| | - Carmela Capobianco
- Clinical Pathology Unit, Azienda Ospedaliero-Universitaria (AOU) Policlinico Consorziale di Bari - Ospedale Giovanni XXIII, Bari, Italy
| | - Stella Vita Marsico
- Clinical Pathology Unit, Azienda Ospedaliero-Universitaria (AOU) Policlinico Consorziale di Bari - Ospedale Giovanni XXIII, Bari, Italy
| | - Tiziana De Chirico
- Clinical Pathology Unit, Azienda Ospedaliero-Universitaria (AOU) Policlinico Consorziale di Bari - Ospedale Giovanni XXIII, Bari, Italy
| | - Carla Pinto
- Clinical Pathology Unit, Azienda Ospedaliero-Universitaria (AOU) Policlinico Consorziale di Bari - Ospedale Giovanni XXIII, Bari, Italy
| | - Lucia Varraso
- Clinical Pathology Unit, Azienda Ospedaliero-Universitaria (AOU) Policlinico Consorziale di Bari - Ospedale Giovanni XXIII, Bari, Italy
| | - Angela Pia Cazzolla
- Department of Clinical and Experimental Medicine, Università degli Studi di Foggia, Foggia, Italy
| | - Francesca Di Serio
- Clinical Pathology Unit, Azienda Ospedaliero-Universitaria (AOU) Policlinico Consorziale di Bari - Ospedale Giovanni XXIII, Bari, Italy
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Zechner C, Adams-Huet B, Gregory B, Neyra JA, Rule JA, Li X, Rakela J, Moe OW, Lee WM. Hypophosphatemia in acute liver failure of a broad range of etiologies is associated with phosphaturia without kidney damage or phosphatonin elevation. Transl Res 2021; 238:1-11. [PMID: 34298149 PMCID: PMC8572166 DOI: 10.1016/j.trsl.2021.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 06/21/2021] [Accepted: 07/15/2021] [Indexed: 11/19/2022]
Abstract
Hypophosphatemia is a common and dangerous complication of acute liver failure (ALF) of various etiologies. While various mechanisms for ALF-associated hypophosphatemia have been proposed including high phosphate uptake into regenerating hepatocytes, acetaminophen (APAP)-associated hypophosphatemia was linked to renal phosphate wasting, and APAP-induced renal tubular injury was proposed as underlying mechanism. We studied 30 normophosphatemic and 46 hypophosphatemic (serum phosphate < 2.5 mg/dL) patients from the Acute Liver Failure Study Group registry with APAP- or non-APAP-induced ALF. Since kidney injury affects phosphate excretion, patients with elevated serum creatinine (>1.2 mg/dL) were excluded. Maximal amount of renal tubular phosphate reabsorption per filtered volume (TmP/GFR) was calculated from simultaneous serum and urine phosphate and creatinine levels to assess renal phosphate handling. Instead of enhanced renal phosphate reabsorption as would be expected during hypophosphatemia of non-renal causes, serum phosphate was positively correlated with TmP/GFR in both APAP- and non-APAP-induced ALF patients (R2 = 0.66 and 0.46, respectively; both P < 0.0001), indicating renal phosphate wasting. Surprisingly, there was no evidence of kidney damage based on urinary markers including neutrophil gelatinase-associated lipocalin and cystatin C even in the APAP group. Additionally, there was no evidence that the known serum phosphatonins parathyroid hormone, fibroblast growth factor 23, and α-Klotho contribute to the observed hypophosphatemia. We conclude that the observed hypophosphatemia with renal phosphate wasting in both APAP- and non-APAP-mediated ALF is likely the result of renal tubular phosphate leak from yet-to-be identified factor(s) with no evidence for proximal tubular damage or contribution of known phosphatonins.
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Affiliation(s)
- Christoph Zechner
- Division of Endocrinology, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA; Department of Pharmacology. UT Southwestern Medical Center, Dallas, Texas, USA; Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, UT Southwestern Medical Center, Dallas, Texas, USA.
| | - Beverley Adams-Huet
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, UT Southwestern Medical Center, Dallas, Texas, USA; Division of Biostatistics, Population and Data Sciences, Department of Clinical Sciences, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Blake Gregory
- Division of Digestive and Liver Diseases, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA; Division of Primary Care, Department of Internal Medicine, Alameda Health System, Oakland, California, USA
| | - Javier A Neyra
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, UT Southwestern Medical Center, Dallas, Texas, USA; Division of Nephrology, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA; Division of Nephrology, Bone and Mineral Metabolism, Department of Internal Medicine, University of Kentucky, Lexington, Kentucky, USA
| | - Jody A Rule
- Division of Digestive and Liver Diseases, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Xilong Li
- Division of Biostatistics, Population and Data Sciences, Department of Clinical Sciences, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Jorge Rakela
- Division of Gastroenterology and Hepatology, Mayo Clinic Arizona, Phoenix, Arizona, USA
| | - Orson W Moe
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, UT Southwestern Medical Center, Dallas, Texas, USA; Division of Nephrology, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA; Department of Physiology, UT Southwestern Medical Center, Dallas, Texas, USA
| | - William M Lee
- Division of Digestive and Liver Diseases, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA.
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14
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Rosner MH, DeMauro Renaghan A. Disorders of Divalent Ions (Magnesium, Calcium, and Phosphorous) in Patients With Cancer. Adv Chronic Kidney Dis 2021; 28:447-459.e1. [PMID: 35190111 DOI: 10.1053/j.ackd.2021.09.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 08/23/2021] [Accepted: 09/08/2021] [Indexed: 12/15/2022]
Abstract
Disorders of the divalent ions (magnesium, calcium, and phosphorous) are frequently encountered in patients with cancer. Of these, hypomagnesemia, hypocalcemia, hypercalcemia, and hypophosphatemia are seen most commonly. These electrolyte disturbances may be related to the underlying malignancy or due to side effects of anticancer therapy. When caused by a paraneoplastic process, these abnormalities may portend a poor prognosis. Importantly, the development of severe electrolyte derangements may be associated with symptoms that negatively impact quality of life, preclude the administration of critical chemotherapeutic agents, or lead to life-threatening complications that require hospitalization and emergent treatment. In accordance, prompt recognition and treatment of these disorders is key to improving outcomes in patients living with cancer. This review will discuss selected derangements of the divalent ions seen in this population, with a focus on paraneoplastic and therapy-associated etiologies.
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15
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Stanczyk M, Chrul S, Wyka K, Tkaczyk M. Serum intact fibroblast growth factor 23 in healthy paediatric population. Open Med (Wars) 2021; 16:1022-1027. [PMID: 34258392 PMCID: PMC8262519 DOI: 10.1515/med-2021-0288] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 03/28/2021] [Accepted: 04/20/2021] [Indexed: 11/25/2022] Open
Abstract
Introduction It is believed that fibroblast growth factor 23 (FGF23) can become an early biomarker of chronic kidney disease progression. Data on FGF23 age dependency are inconsistent. We present the results of the cross-sectional study concerning FGF23 levels in healthy Polish children. Material and methods This study was conducted in 121 children aged 0–18 years. Kidney function and intact FGF23 levels in serum were assessed. Differences between age groups and according to gender were analysed. Results The difference in FGF23 between age groups and according to gender was statistically insignificant. In the youngest and the oldest group, a trend to higher FGF23 levels was observed. FGF23 level in girls tended to be higher than boys, apart from the age group between 1 and 4 years. There was a negative correlation between eGFR and FGF23 (r = −0.26, p < 0.05) – strong in girls (r = −0.38, p < 0.05), but not in boys. In each age group, we found no significant correlation between eGFR and FGF23. Conclusions Our study supports the evidence that the FGF23 level in paediatric population is not age or sex dependent. The results can serve as a reference point under clinical conditions and for other studies on the topic.
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Affiliation(s)
- Malgorzata Stanczyk
- Department of Pediatrics, Immunology and Nephrology, Polish Mother's Memorial Hospital Research Institute, Rzgowska 281/289, Lodz 93-338, Poland.,Department of Pediatrics, Preventive Cardiology and Immunology of Developmental Age, Medical University of Lodz, Poland
| | - Slawomir Chrul
- Department of Pediatrics, Immunology and Nephrology, Polish Mother's Memorial Hospital Research Institute, Lodz 93-338, Poland
| | - Krystyna Wyka
- Department of Pediatrics, Oncology and Hematology, Medical University of Lodz, Lodz, Poland
| | - Marcin Tkaczyk
- Department of Pediatrics, Immunology and Nephrology, Polish Mother's Memorial Hospital Research Institute, Lodz 93-338, Poland.,Department of Pediatrics, Preventive Cardiology and Immunology of Developmental Age, Medical University of Lodz, Poland
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16
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Figueres L, Beck-Cormier S, Beck L, Marks J. The Complexities of Organ Crosstalk in Phosphate Homeostasis: Time to Put Phosphate Sensing Back in the Limelight. Int J Mol Sci 2021; 22:5701. [PMID: 34071837 PMCID: PMC8199323 DOI: 10.3390/ijms22115701] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 05/13/2021] [Accepted: 05/21/2021] [Indexed: 12/16/2022] Open
Abstract
Phosphate homeostasis is essential for health and is achieved via interaction between the bone, kidney, small intestine, and parathyroid glands and via intricate processes involving phosphate transporters, phosphate sensors, and circulating hormones. Numerous genetic and acquired disorders are associated with disruption in these processes and can lead to significant morbidity and mortality. The role of the kidney in phosphate homeostasis is well known, although it is recognized that the cellular mechanisms in murine models and humans are different. Intestinal phosphate transport also appears to differ in humans and rodents, with recent studies demonstrating a dominant role for the paracellular pathway. The existence of phosphate sensing has been acknowledged for decades; however, the underlying molecular mechanisms are poorly understood. At least three phosphate sensors have emerged. PiT2 and FGFR1c both act as phosphate sensors controlling Fibroblast Growth Factor 23 secretion in bone, whereas the calcium-sensing receptor controls parathyroid hormone secretion in response to extracellular phosphate. All three of the proposed sensors are expressed in the kidney and intestine but their exact function in these organs is unknown. Understanding organ interactions and the mechanisms involved in phosphate sensing requires significant research to develop novel approaches for the treatment of phosphate homeostasis disorders.
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Affiliation(s)
- Lucile Figueres
- Department of Neuroscience, Physiology and Pharmacology, Royal Free Campus, University College London, London NW3 2PF, UK;
- CHU de Nantes, Université de Nantes, F-44042 Nantes, France
| | - Sarah Beck-Cormier
- Inserm, UMR 1229, RMeS Regenerative Medicine and Skeleton, Université de Nantes, ONIRIS, F-44042 Nantes, France; (S.B.-C.); (L.B.)
| | - Laurent Beck
- Inserm, UMR 1229, RMeS Regenerative Medicine and Skeleton, Université de Nantes, ONIRIS, F-44042 Nantes, France; (S.B.-C.); (L.B.)
| | - Joanne Marks
- Department of Neuroscience, Physiology and Pharmacology, Royal Free Campus, University College London, London NW3 2PF, UK;
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Effects and interaction of dietary calcium and non-phytate phosphorus for slow-growing yellow-feathered broilers during the starter phase. Animal 2021; 15:100201. [PMID: 34029793 DOI: 10.1016/j.animal.2021.100201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 02/01/2021] [Accepted: 02/02/2021] [Indexed: 01/24/2023] Open
Abstract
Calcium (Ca) and non-phytate phosphorus (NPP) are fundamental minerals for bone formation and growth, and optimizing their level is required in broiler production. This experiment was conducted to investigate the effect and interaction of dietary Ca and NPP on growth performance, tibial characteristics and biochemical variables for slow-growing yellow-feathered broilers during 1-28 d (the starter phase). Seven hundred and twenty hatchling female broilers were randomly divided into nine groups, which received three levels of Ca (0.80%, 0.90%, 1.00%) each with three levels of NPP (0.40%, 0.45%, 0.50%). The results showed: (1) Dietary Ca level influenced (P < 0.05) the feed to gain ratio (F:G) and average daily feed intake (ADFI). Compared with broilers provided 1.00% Ca, ADFI of birds provided with 0.80% or 0.90% Ca and F:G of those with 0.90% Ca were decreased (P < 0.05). Dietary NPP level did not affect (P > 0.05) growth performance of broilers. (2) Dietary Ca affected (P < 0.05) tibial length. Compared with birds provided with 0.80% Ca, the length of tibia was decreased (P < 0.05) in birds received 1.00% Ca. Interactions between dietary Ca and NPP were observed (P < 0.05) on ash content, breaking strength and bone density of tibia. These three characteristics were better when birds received 0.90% Ca and 0.40% NPP or 1.00% Ca and 0.45% NPP. (3) Dietary Ca significantly affected (P < 0.05) the activity of alkaline phosphatase (ALP) in serum with decreased activity in birds fed 0.80% or 0.90% Ca. The dietary NPP influenced (P < 0.05) the contents of Ca in serum. Serum Ca was increased when birds were provided 0.40% NPP compared with other levels (P < 0.05). Again, there was interaction between Ca and NPP in diet on the contents of phosphorus (P) in serum (P < 0.05). In conclusion, interactions occurred between dietary Ca and NPP level on tibial breaking strength, density, ash content, and the content of P in the serum of young yellow-feathered broilers. Furthermore, dietary Ca affected ADFI, F:G and serum ALP activity, and dietary NPP also affected the P content in serum. Considering all indicators, 0.90% Ca and 0.40% NPP are optimal for slow-growing yellow-feathered broilers during 1-28 d of age.
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18
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Bird RP, Eskin NAM. The emerging role of phosphorus in human health. ADVANCES IN FOOD AND NUTRITION RESEARCH 2021; 96:27-88. [PMID: 34112356 DOI: 10.1016/bs.afnr.2021.02.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Phosphorus, an essential nutrient, performs vital functions in skeletal and non-skeletal tissues and is pivotal for energy production. The last two decades of research on the physiological importance of phosphorus have provided several novel insights about its dynamic nature as a nutrient performing functions as a phosphate ion. Phosphorous also acts as a signaling molecule and induces complex physiological responses. It is recognized that phosphorus homeostasis is critical for health. The intake of phosphorus by the general population world-wide is almost double the amount required to maintain health. This increase is attributed to the incorporation of phosphate containing food additives in processed foods purchased by consumers. Research findings assessed the impact of excessive phosphorus intake on cells' and organs' responses, and highlighted the potential pathogenic consequences. Research also identified a new class of bioactive phosphates composed of polymers of phosphate molecules varying in chain length. These polymers are involved in metabolic responses including hemostasis, brain and bone health, via complex mechanism(s) with positive or negative health effects, depending on their chain length. It is amazing, that phosphorus, a simple element, is capable of exerting multiple and powerful effects. The role of phosphorus and its polymers in the renal and cardiovascular system as well as on brain health appear to be important and promising future research directions.
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Affiliation(s)
- Ranjana P Bird
- School of Health Sciences, University of Northern British Columbia, Prince George, BC, Canada.
| | - N A Michael Eskin
- Department of Food and Human Nutritional Sciences, Faculty of Agricultural and Food Sciences, University of Manitoba, Winnipeg, MB, Canada
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Abstract
Phosphorus plays a vital role in diverse biological processes including intracellular signaling, membrane integrity, and skeletal biomineralization; therefore, the regulation of phosphorus homeostasis is essential to the well-being of the organism. Cells and whole organisms respond to changes in inorganic phosphorus (Pi) concentrations in their environment by adjusting Pi uptake and altering biochemical processes in cells (local effects) and distant organs (endocrine effects). Unicellular organisms, such as bacteria and yeast, express specific Pi-binding proteins on the plasma membrane that respond to changes in ambient Pi availability and transduce intracellular signals that regulate the expression of genes involved in cellular Pi uptake. Multicellular organisms, including humans, respond at a cellular level to adapt to changes in extracellular Pi concentrations and also have endocrine pathways which integrate signals from various organs (e.g., intestine, kidneys, parathyroid glands, bone) to regulate serum Pi concentrations and whole-body phosphorus balance. In mammals, alterations in the concentrations of extracellular Pi modulate type III sodium-phosphate cotransporter activity on the plasma membrane, and trigger changes in cellular function. In addition, elevated extracellular Pi induces activation of fibroblast growth factor receptor, Raf/mitogen-activated protein kinase/ERK kinase (MEK)/extracellular signal-regulated kinase (ERK) and Akt pathways, which modulate gene expression in various mammalian cell types. Excessive Pi exposure, especially in patients with chronic kidney disease, leads to endothelial dysfunction, accelerated vascular calcification, and impaired insulin secretion.
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Affiliation(s)
- Kittrawee Kritmetapak
- Division of Nephrology, Department of Medicine, Faculty of Medicine, Khon Kaen University, Khon Kaen, 40002, Thailand
- Division of Nephrology and Hypertension, Departments of Medicine, Biochemistry and Molecular Biology, Mayo Clinic, 200 First Street Southwest, Rochester, MN, 55902, USA
| | - Rajiv Kumar
- Division of Nephrology and Hypertension, Departments of Medicine, Biochemistry and Molecular Biology, Mayo Clinic, 200 First Street Southwest, Rochester, MN, 55902, USA.
- Nephrology Research, Medical Sciences 1-120, 200 First Street Southwest, Rochester, MN, 55902, USA.
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20
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Nordholm A, Egstrand S, Gravesen E, Mace ML, Morevati M, Olgaard K, Lewin E. Circadian rhythm of activin A and related parameters of mineral metabolism in normal and uremic rats. Pflugers Arch 2019; 471:1079-1094. [PMID: 31236663 PMCID: PMC6614158 DOI: 10.1007/s00424-019-02291-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 06/04/2019] [Accepted: 06/05/2019] [Indexed: 12/11/2022]
Abstract
Activin A is a new fascinating player in chronic kidney disease-mineral and bone disorder (CKD-MBD), which is implicated in progressive renal disease, vascular calcification, and osteodystrophy. Plasma activin A rises early in the progression of renal disease. Disruption of circadian rhythms is related to increased risk of several diseases and circadian rhythms are observed in mineral homeostasis, bone parameters, and plasma levels of phosphate and PTH. Therefore, we examined the circadian rhythm of activin A and CKD-MBD-related parameters (phosphate, PTH, FGF23, and klotho) in healthy controls and CKD rats (5/6 nephrectomy) on high-, standard- and low-dietary phosphate contents as well as during fasting conditions. Plasma activin A exhibited circadian rhythmicity in healthy control rats with fourfold higher values at acrophase compared with nadir. The rhythm was obliterated in CKD. Activin A was higher in CKD rats compared with controls when measured at daytime but not significantly when measured at evening/nighttime, stressing the importance of time-specific reference intervals when interpreting plasma values. Plasma phosphate, PTH, and FGF23 all showed circadian rhythms in control rats, which were abolished or disrupted in CKD. Plasma klotho did not show circadian rhythm. Thus, the present investigation shows, for the first time, circadian rhythm of plasma activin A. The rhythmicity is severely disturbed by CKD and is associated with disturbed rhythms of phosphate and phosphate-regulating hormones PTH and FGF23, indicating that disturbed circadian rhythmicity is an important feature of CKD-MBD.
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Affiliation(s)
- Anders Nordholm
- Nephrological Department, Herlev Hospital, University of Copenhagen, 2730, Herlev, Denmark.,Nephrological Department, Rigshospitalet, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Søren Egstrand
- Nephrological Department, Herlev Hospital, University of Copenhagen, 2730, Herlev, Denmark.,Nephrological Department, Rigshospitalet, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Eva Gravesen
- Nephrological Department, Rigshospitalet, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Maria L Mace
- Nephrological Department, Herlev Hospital, University of Copenhagen, 2730, Herlev, Denmark.,Nephrological Department, Rigshospitalet, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Marya Morevati
- Nephrological Department, Rigshospitalet, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Klaus Olgaard
- Nephrological Department, Rigshospitalet, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Ewa Lewin
- Nephrological Department, Herlev Hospital, University of Copenhagen, 2730, Herlev, Denmark. .,Nephrological Department, Rigshospitalet, University of Copenhagen, 2100, Copenhagen, Denmark.
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Proszkowiec-Weglarz M, Schreier LL, Miska KB, Angel R, Kahl S, Russell B. Effect of early neonatal development and delayed feeding post-hatch on jejunal and ileal calcium and phosphorus transporter genes expression in broiler chickens. Poult Sci 2019; 98:1861-1871. [PMID: 30508138 DOI: 10.3382/ps/pey546] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 11/08/2018] [Indexed: 12/30/2022] Open
Abstract
Calcium (Ca) and phosphorus (P) are essential minerals involved in many biological processes including bone development and mineralization. Plasma concentration of both minerals is tightly regulated, and Ca and P homeostasis is maintained via intestinal absorption, bone storage and exchange, and renal reabsorption. In the current broiler production systems, chicks are deprived of food and water for up to 72 h due to uneven hatching, hatchery procedures, and transportation time to farms. Post-hatch (PH) feed delay results in lower body and organ weight, higher feed conversion ratio and mortality, and delayed PH growth and GIT development. Little is known about the effects of early neonatal development and delayed or immediate feeding PH on Ca and P transporters. Therefore, the aim of the present study was to characterize expression patterns of Ca and P transporter genes in small intestine during the first 2 wk PH in chickens fed immediately after hatch (FED) or subjected to 48 h delayed feeding (NOTFED). Expression of all Ca and P transporters in jejunum and ileum was significantly (P < 0.05) affected by age. Among Ca transporter genes, only mRNA expression of Calbidin D28k in jejunum and Ca sensing receptor (CaSR) in ileum were significantly (P < 0.05) affected by delay in feed access. For P transporter genes' expression, only P transporter type III (PIT1) mRNA was significantly affected by age, delay in feed access, and their interaction (P < 0.05). In summary, we have shown, for the first time, early developmental changes of Ca and P transporter genes in broiler chickens. Results suggest that an increase in gene expression of some of the transporters corresponds with the switch from yolk to high starch diet. Overall, our results can be helpful in better understanding of Ca and P homeostasis in broilers.
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Affiliation(s)
- Monika Proszkowiec-Weglarz
- United States Department of Agriculture, Agricultural Research Service, Animal Biosciences and Biotechnology Laboratory, Beltsville, MD 20705, USA
| | - Lori L Schreier
- United States Department of Agriculture, Agricultural Research Service, Animal Biosciences and Biotechnology Laboratory, Beltsville, MD 20705, USA
| | - Katarzyna B Miska
- United States Department of Agriculture, Agricultural Research Service, Animal Biosciences and Biotechnology Laboratory, Beltsville, MD 20705, USA
| | - Roselina Angel
- Department of Animal and Avian Sciences, University of Maryland, College Park, MD 20742, USA
| | - Stanislaw Kahl
- United States Department of Agriculture, Agricultural Research Service, Animal Biosciences and Biotechnology Laboratory, Beltsville, MD 20705, USA
| | - Beverly Russell
- United States Department of Agriculture, Agricultural Research Service, Animal Biosciences and Biotechnology Laboratory, Beltsville, MD 20705, USA
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Holden RM, Hétu MF, Li TY, Ward E, Couture LE, Herr JE, Christilaw E, Adams MA, Johri AM. The Heart and Kidney: Abnormal Phosphate Homeostasis Is Associated With Atherosclerosis. J Endocr Soc 2018; 3:159-170. [PMID: 30620003 PMCID: PMC6316987 DOI: 10.1210/js.2018-00311] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 11/20/2018] [Indexed: 11/19/2022] Open
Abstract
Context Phosphate has gained recognition as a risk factor for adverse cardiovascular outcomes, potentially due to accelerated vascular calcification. Fibroblast growth factor-23 (FGF-23) is a counter-regulatory hormone that increases renal phosphate excretion to maintain normal levels. Objective The purpose of the study was to determine the association of phosphate and FGF-23 to atherosclerosis. Design and Setting A prospective cohort study (n = 204) of outpatients referred for coronary angiography over of a 1-year recruitment period at the Kingston General Hospital. Intervention Blood was collected, and a focused carotid ultrasound was performed. Main Outcome Measure Degree of angiographic coronary artery disease was scored. Carotid maximum plaque height, total area, grayscale median, and tissue pixel distribution were measured. Plasma phosphate was assessed by mineral assay and FGF-23 by ELISA. Results Carotid plaque burden [total plaque area (TPA)] was associated with higher levels of phosphate (TPA, r = 0.20, P < 0.01) and FGF-23 (r = 0.19, P < 0.01). FGF-23 was associated with increased plaque % calcium-like tissue. Participants with no coronary artery disease had significantly lower phosphate levels. Phosphate was associated with higher grayscale median (GSM) in male subjects but with lower GSM in female subjects. FGF-23 was associated with increased plaque % fat in male subjects but increased plaque % calcium in female subjects. Conclusions Phosphate was independently associated with the severity of atherosclerosis in terms of plaque burden and composition. FGF-23 was associated with plaque calcification. These findings suggest that abnormal phosphate homeostasis may play an under-recognized but potentially modifiable role in cardiovascular disease.
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Affiliation(s)
- Rachel M Holden
- Department of Medicine, Queen's University, Kingston, Ontario, Canada.,Department of Biomedical and Molecular Science, Queen's University, Kingston, Ontario, Canada
| | - Marie-France Hétu
- Department of Medicine, Division of Cardiology, Cardiovascular Imaging Network at Queen's University, Kingston, Ontario, Canada
| | - Terry Y Li
- Department of Biomedical and Molecular Science, Queen's University, Kingston, Ontario, Canada
| | - Emilie Ward
- Department of Biomedical and Molecular Science, Queen's University, Kingston, Ontario, Canada
| | - Laura E Couture
- Department of Biomedical and Molecular Science, Queen's University, Kingston, Ontario, Canada
| | - Julia E Herr
- Department of Medicine, Division of Cardiology, Cardiovascular Imaging Network at Queen's University, Kingston, Ontario, Canada
| | - Erin Christilaw
- Department of Medicine, Queen's University, Kingston, Ontario, Canada
| | - Michael A Adams
- Department of Biomedical and Molecular Science, Queen's University, Kingston, Ontario, Canada
| | - Amer M Johri
- Department of Biomedical and Molecular Science, Queen's University, Kingston, Ontario, Canada.,Department of Medicine, Division of Cardiology, Cardiovascular Imaging Network at Queen's University, Kingston, Ontario, Canada
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23
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Abstract
Inorganic phosphate (Pi) is essential for signal transduction and cell metabolism, and is also an essential structural component of the extracellular matrix of the skeleton. Pi is sensed in bacteria and yeast at the plasma membrane, which activates intracellular signal transduction to control the expression of Pi transporters and other genes that control intracellular Pi levels. In multicellular organisms, Pi homeostasis must be maintained in the organism and at the cellular level, requiring an endocrine and metabolic Pi-sensing mechanism, about which little is currently known. This Review will discuss the metabolic effects of Pi, which are mediated by Pi transporters, inositol pyrophosphates and SYG1-Pho81-XPR1 (SPX)-domain proteins to maintain cellular phosphate homeostasis in the musculoskeletal system. In addition, we will discuss how Pi is sensed by the human body to regulate the production of fibroblast growth factor 23 (FGF23), parathyroid hormone and calcitriol to maintain serum levels of Pi in a narrow range. New findings on the crosstalk between iron and Pi homeostasis in the regulation of FGF23 expression will also be outlined. Mutations in components of these metabolic and endocrine phosphate sensors result in genetic disorders of phosphate homeostasis, cardiomyopathy and familial basal ganglial calcifications, highlighting the importance of this newly emerging area of research.
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Affiliation(s)
- Sampada Chande
- Section of Endocrinology and Metabolism, Yale University School of Medicine, New Haven, CT, USA
| | - Clemens Bergwitz
- Section of Endocrinology and Metabolism, Yale University School of Medicine, New Haven, CT, USA.
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24
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Marks J. The role of SLC34A2 in intestinal phosphate absorption and phosphate homeostasis. Pflugers Arch 2018; 471:165-173. [PMID: 30343332 PMCID: PMC6325986 DOI: 10.1007/s00424-018-2221-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 10/08/2018] [Accepted: 10/10/2018] [Indexed: 12/13/2022]
Abstract
There has recently been significant interest in the concept of directly targeting intestinal phosphate transport to control hyperphosphatemia in patients with chronic kidney disease. However, we do not have a complete understanding of the cellular mechanisms that govern dietary phosphate absorption. Studies in the 1970s documented both active and passive pathways for intestinal phosphate absorption. However, following the cloning of the intestinal SLC34 cotransporter, NaPi-IIb, much of the research focused on the role of this protein in active transcellular phosphate absorption and the factors involved in its regulation. Generation of a conditional NaPi-IIb knockout mouse has demonstrated that this protein is critical for the maintenance of skeletal integrity during periods of phosphate restriction and that under normal physiological conditions, the passive sodium-independent pathway is likely be the more dominant pathway for intestinal phosphate absorption. The review aims to summarise the most recent developments in our understanding of the role of the intestine in phosphate homeostasis, including the acute and chronic renal adaptations that occur in response to dietary phosphate intake. Evidence regarding the overall contribution of the transcellular and paracellular pathways for phosphate absorption will be discussed, together with the clinical benefit of inhibiting these pathways for the treatment of hyperphosphatemia in chronic kidney disease.
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Affiliation(s)
- Joanne Marks
- Department of Neuroscience, Physiology and Pharmacology, Royal Free Campus, University College London, Rowland Hill Street, London, NW3 2PF, UK.
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25
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Michigami T, Kawai M, Yamazaki M, Ozono K. Phosphate as a Signaling Molecule and Its Sensing Mechanism. Physiol Rev 2018; 98:2317-2348. [DOI: 10.1152/physrev.00022.2017] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
In mammals, phosphate balance is maintained by influx and efflux via the intestines, kidneys, bone, and soft tissue, which involves multiple sodium/phosphate (Na+/Pi) cotransporters, as well as regulation by several hormones. Alterations in the levels of extracellular phosphate exert effects on both skeletal and extra-skeletal tissues, and accumulating evidence has suggested that phosphate itself evokes signal transduction to regulate gene expression and cell behavior. Several in vitro studies have demonstrated that an elevation in extracellular Piactivates fibroblast growth factor receptor, Raf/MEK (mitogen-activated protein kinase/ERK kinase)/ERK (extracellular signal-regulated kinase) pathway and Akt pathway, which might involve the type III Na+/Picotransporter PiT-1. Excessive phosphate loading can lead to various harmful effects by accelerating ectopic calcification, enhancing oxidative stress, and dysregulating signal transduction. The responsiveness of mammalian cells to altered extracellular phosphate levels suggests that they may sense and adapt to phosphate availability, although the precise mechanism for phosphate sensing in mammals remains unclear. Unicellular organisms, such as bacteria and yeast, use some types of Pitransporters and other molecules, such as kinases, to sense the environmental Piavailability. Multicellular animals may need to integrate signals from various organs to sense the phosphate levels as a whole organism, similarly to higher plants. Clarification of the phosphate-sensing mechanism in humans may lead to the development of new therapeutic strategies to prevent and treat diseases caused by phosphate imbalance.
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Affiliation(s)
- Toshimi Michigami
- Department of Bone and Mineral Research, Research Institute, Osaka Women’s and Children’s Hospital, Osaka Prefectural Hospital Organization, Izumi, Osaka, Japan; and Department of Pediatrics, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Masanobu Kawai
- Department of Bone and Mineral Research, Research Institute, Osaka Women’s and Children’s Hospital, Osaka Prefectural Hospital Organization, Izumi, Osaka, Japan; and Department of Pediatrics, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Miwa Yamazaki
- Department of Bone and Mineral Research, Research Institute, Osaka Women’s and Children’s Hospital, Osaka Prefectural Hospital Organization, Izumi, Osaka, Japan; and Department of Pediatrics, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Keiichi Ozono
- Department of Bone and Mineral Research, Research Institute, Osaka Women’s and Children’s Hospital, Osaka Prefectural Hospital Organization, Izumi, Osaka, Japan; and Department of Pediatrics, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
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26
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Hernando N, Wagner CA. Mechanisms and Regulation of Intestinal Phosphate Absorption. Compr Physiol 2018; 8:1065-1090. [PMID: 29978897 DOI: 10.1002/cphy.c170024] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
States of hypo- and hyperphosphatemia have deleterious consequences including rickets/osteomalacia and renal/cardiovascular disease, respectively. Therefore, the maintenance of appropriate plasma levels of phosphate is an essential requirement for health. This control is executed by the collaborative action of intestine and kidney whose capacities to (re)absorb phosphate are regulated by a number of hormonal and metabolic factors, among them parathyroid hormone, fibroblast growth factor 23, 1,25(OH)2 vitamin D3 , and dietary phosphate. The molecular mechanisms responsible for the transepithelial transport of phosphate across enterocytes are only partially understood. Indeed, whereas renal reabsorption entirely relies on well-characterized active transport mechanisms of phosphate across the renal proximal epithelia, intestinal absorption proceeds via active and passive mechanisms, with the molecular identity of the passive component still unknown. The active absorption of phosphate depends mostly on the activity and expression of the sodium-dependent phosphate cotransporter NaPi-IIb (SLC34A2), which is highly regulated by many of the factors, mentioned earlier. Physiologically, the contribution of NaPi-IIb to the maintenance of phosphate balance appears to be mostly relevant during periods of low phosphate availability. Therefore, its role in individuals living in industrialized societies with high phosphate intake is probably less relevant. Importantly, small increases in plasma phosphate, even within normal range, associate with higher risk of cardiovascular disease. Therefore, therapeutic approaches to treat hyperphosphatemia, including dietary phosphate restriction and phosphate binders, aim at reducing intestinal absorption. Here we review the current state of research in the field. © 2017 American Physiological Society. Compr Physiol 8:1065-1090, 2018.
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Affiliation(s)
- Nati Hernando
- National Center for Competence in Research NCCR Kidney.CH, Institute of Physiology, University Zurich-Irchel, Zurich, Switzerland
| | - Carsten A Wagner
- National Center for Competence in Research NCCR Kidney.CH, Institute of Physiology, University Zurich-Irchel, Zurich, Switzerland
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27
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Tabibzadeh N, Mentaverri R, Daroux M, Mesbah R, Delpierre A, Paul JG, Deken V, Massy ZA, Bataille P. Differential Determinants of Tubular Phosphate Reabsorption: Insights on Renal Excretion of Phosphates in Kidney Disease. Am J Nephrol 2018; 47:300-303. [PMID: 29779025 DOI: 10.1159/000488864] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 03/27/2018] [Indexed: 12/20/2022]
Abstract
We assessed the tubular reabsorption of phosphate (TRP) and maximal renal threshold for phosphate reabsorption to glomerular filtration rate (TmPi/GFR) and their determinants in 64 stages 2-4 chronic kidney disease (CKD) patients in order to define the early changes in phosphate metabolism in CKD. In multivariable analysis, TmPi/GFR correlates were estimated GFR (eGFR), intact parathyroid hormone (iPTH), and hemoglobin (R2 = 0.417), while TRP correlates were eGFR, iPTH, 24-h phosphaturia, and calcitriol (R2 = 0.72). This suggests that TmPi/GFR and TRP, respectively, assess hemoglobin-phosphate and bowel-kidney phosphate regulation axis. Iron supplementation based on TmPi/GFR or earlier phosphate restriction based on TRP should be investigated in view of modifying clinical outcomes in CKD.
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Affiliation(s)
- Nahid Tabibzadeh
- Department of Nephrology, CH Boulogne-sur-Mer, Boulogne-sur-Mer, France
| | - Romuald Mentaverri
- INSERM U1088, Jules Verne University of Picardie, Amiens, France
- Laboratory of Endocrine and Bone Biology, University Hospital, Amiens, France
| | - Maïté Daroux
- Department of Nephrology, CH Boulogne-sur-Mer, Boulogne-sur-Mer, France
| | - Rafik Mesbah
- Department of Nephrology, CH Boulogne-sur-Mer, Boulogne-sur-Mer, France
| | - Alexia Delpierre
- Department of Nephrology, CH Boulogne-sur-Mer, Boulogne-sur-Mer, France
| | - Jean-Gabriel Paul
- Laboratory of Biology, CH Boulogne-sur-Mer, Boulogne-sur-Mer, France
| | - Valérie Deken
- Department of Biostatistics, EA 2694 - Santé publique : épidémiologie et qualité des soins, University Lille, CHU Lille, Lille, France
| | - Ziad A Massy
- Division of Nephrology, Ambroise Paré Hospital-APHP and Paris Ile de France Ouest University (UVSQ), Boulogne-Billancourt, France
- Inserm U-1018, Centre de Recherche en Epidémiologie et Santé des Populations (CESP), Equipe 5, Villejuif, France
- University of Paris Ouest-Versailles-Saint-Quentin-en-Yvelines (UVSQ), Versailles, France
| | - Pierre Bataille
- Department of Nephrology, CH Boulogne-sur-Mer, Boulogne-sur-Mer, France
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28
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Levac BM, Adams MA, Pyke KE. The impact of an acute oral phosphate load on endothelium dependent and independent brachial artery vasodilation in healthy males. Appl Physiol Nutr Metab 2017; 42:1307-1315. [DOI: 10.1139/apnm-2017-0147] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Serum phosphate levels are associated with cardiovascular morbidity and mortality in the general population and endothelial dysfunction may be mechanistically involved. The purpose of this study was to investigate the effects of acute phosphate supplementation on endothelial-dependent (flow-mediated dilation; FMD) and -independent (glyceryl trinitrate; GTN)) vasodilation in young, healthy males. Seventeen healthy male participants (age, 23 ± 3 years) were exposed to an oral load of phosphate (PHOS; liquid supplement containing 1200 mg of phosphorous) and placebo (PLAC) over 2 experimental days. A brachial artery FMD test was performed pre-ingestion and at 20 min, 60 min, and 120 min following the ingestion of the phosphate load or the placebo. GTN tests were performed pre- and 140 min post-ingestion. Serum phosphate was not impacted differently by phosphate versus placebo ingestion (p = 0.780). In contrast, urinary phosphate excretion was markedly increased in the PHOS (p < 0.001) but not in the PLAC condition (p = 0.130) (Δ fractional excretion of phosphate in PHOS (29.2%) vs. PLAC (9.3%)). This indicates that circulating phosphate levels were homeostatically regulated. GTN-mediated vasodilation was not significantly affected by phosphate ingestion. In primary analysis no impact of phosphate ingestion on FMD was detected. However, when the shear stress stimulus was added as a covariate in a subset of participants, exploratory pairwise comparisons revealed a significantly lower FMD 20 min post-phosphate ingestion versus placebo (p = 0.024). The effects of phosphate ingestion on FMD and serum phosphate are in contrast with previous findings and the mechanisms that underlie the disparate results require further investigation.
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Affiliation(s)
- Brendan M. Levac
- Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies, Queen’s University, Kingston, ON K7L 3N6, Canada
| | - Michael A. Adams
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, ON K7L 3N6, Canada
| | - Kyra E. Pyke
- Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies, Queen’s University, Kingston, ON K7L 3N6, Canada
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Role of pyrophosphate in vascular calcification in chronic kidney disease. Nefrologia 2017; 38:250-257. [PMID: 29137892 DOI: 10.1016/j.nefro.2017.07.005] [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: 09/19/2016] [Revised: 07/06/2017] [Accepted: 07/20/2017] [Indexed: 01/29/2023] Open
Abstract
Vascular calcification is a pathology characterized by the deposition of calcium-phosphate in cardiovascular structures, mainly in the form of hydroxyapatite crystals, resulting in ectopic calcification. It is correlated with increased risk of cardiovascular disease and myocardial infarction in diabetic patients and in those with chronic kidney disease (CKD). Vascular smooth muscle cells are sensitive to changes in inorganic phosphate (Pi) levels. They are able to adapt and modify some of their functions and promote changes which trigger calcification. Pi is regulated by parathyroid hormone and 1,25-dihydroxyvitamin D. Changes in the transport of Pi are the primary factor responsible for the regulation of Pi homeostasis and the calcification process. Synthesis of calcification inhibitors is the main mechanism by which cells are able to prevent vascular calcification. Extracellular pyrophosphate (PPi) is a potent endogenous inhibitor of calcium-phosphate deposition both in vivo and in vitro. Patients with CKD show lower levels of PPi and increased activity of the enzyme alkaline phosphatase. Numerous enzymes implicated in the metabolism of PPi have been associated with vascular calcifications. PPi is synthesized from extracellular ATP by nucleotide pyrophosphatase/phosphodiesterase from extracellular ATP hydrolysis. PPi is hydrolyzed into Pi by tissue-nonspecific alkaline phosphatase. ATP can be hydrolyzed to Pi via the ectonucleoside triphosphate diphosphohydrolase family. All these enzymes must be in balance, thereby preventing calcifications. However, diseases like CKD or diabetes induce alterations in their levels. Administration of PPi could open up new treatment options for these patients.
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Shimodaira M, Okaniwa S, Nakayama T. Reduced Serum Phosphorus Levels Were Associated with Metabolic Syndrome in Men But Not in Women: A Cross-Sectional Study among the Japanese Population. ANNALS OF NUTRITION AND METABOLISM 2017; 71:150-156. [PMID: 28881349 DOI: 10.1159/000480354] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Accepted: 08/13/2017] [Indexed: 12/18/2022]
Abstract
BACKGROUND Reduced serum phosphorus (SP) levels are reported to be associated with insulin resistance and metabolic syndrome (MetS). However, there have been a few gender-specific studies although SP levels are substantially different between men and women. METHODS This is a cross-sectional study. A total of 16,041 subjects (9,076 men and 6,965 women) were analyzed. The subjects were divided into 3 groups of gender-specific tertiles based on phosphorus levels: the lowest (T1), middle (T2), and the highest (T3). RESULTS SP levels were significantly lower in subjects with MetS than in those without MetS in men but not in women. Waist circumference and fasting plasma glucose were negatively and high-density lipoprotein cholesterol was positively correlated with SP levels both in men and women. Blood pressure (BP) and triglycerides (TG) were negatively correlated with SP levels in men, while they were positively correlated with SP levels in women. Lower SP levels were associated with the prevalence of MetS in men (T1; 19.9%, T2; 16.9%, and T3; 14.3%; p < 0.001) but not in women (T1; 14.1%, T2; 16.6%, and T3; 15.3%; p = 0.282). CONCLUSION BP and TG were unexpectedly positively correlated with SP levels in women. Reduced SP levels were associated with MetS in men but not in women.
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Minisola S, Peacock M, Fukumoto S, Cipriani C, Pepe J, Tella SH, Collins MT. Tumour-induced osteomalacia. Nat Rev Dis Primers 2017; 3:17044. [PMID: 28703220 DOI: 10.1038/nrdp.2017.44] [Citation(s) in RCA: 185] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Tumour-induced osteomalacia (TIO), also known as oncogenic osteomalacia, is a rare paraneoplastic disorder caused by tumours that secrete fibroblast growth factor 23 (FGF23). Owing to the role of FGF23 in renal phosphate handling and vitamin D synthesis, TIO is characterized by decreased renal tubular reabsorption of phosphate, by hypophosphataemia and by low levels of active vitamin D. Chronic hypophosphataemia ultimately results in osteomalacia (that is, inadequate bone mineralization). The diagnosis of TIO is usually suspected when serum phosphate levels are chronically low in the setting of bone pain, fragility fractures and muscle weakness. Locating the offending tumour can be very difficult, as the tumour is often very small and can be anywhere in the body. Surgical removal of the tumour is the only definitive treatment. When the tumour cannot be located or when complete resection is not possible, medical treatment with phosphate salts or active vitamin D is necessary. One of the most promising emerging treatments for unresectable tumours that cause TIO is the anti-FGF23 monoclonal antibody KRN23. The recent identification of a fusion of fibronectin and fibroblast growth factor receptor 1 (FGFR1) as a molecular driver in some tumours not only sheds light on the pathophysiology of TIO but also opens the door to a better understanding of the transcription, translocation, post-translational modification and secretion of FGF23, as well as suggesting approaches to targeted therapy. Further study will reveal if the FGFR1 pathway is also involved in tumours that do not harbour the translocation.
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Affiliation(s)
- Salvatore Minisola
- Department of Internal Medicine and Medical Disciplines, Sapienza University of Rome, Viale del Policlinico 155, 00161 Rome, Italy
| | - Munro Peacock
- Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Seijii Fukumoto
- Fujii Memorial Institute of Medical Sciences, Institute of Advanced Medical Sciences, Tokushima University, Tokushima, Japan
| | - Cristiana Cipriani
- Department of Internal Medicine and Medical Disciplines, Sapienza University of Rome, Viale del Policlinico 155, 00161 Rome, Italy
| | - Jessica Pepe
- Department of Internal Medicine and Medical Disciplines, Sapienza University of Rome, Viale del Policlinico 155, 00161 Rome, Italy
| | - Sri Harsha Tella
- Section on Skeletal Disorders and Mineral Homeostasis, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, USA.,Endocrinology and Metabolism, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Michael T Collins
- Section on Skeletal Disorders and Mineral Homeostasis, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, USA
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Abstract
The vertebrate endoskeleton is not a mere frame for muscle attachment to facilitate locomotion, but is a massive organ integrated with many physiologic functions including mineral and energy metabolism. Mineral balance is maintained by tightly controlled ion fluxes that are external (intestine and kidney) and internal (between bone and other organs), and are regulated and coordinated by many endocrine signals between these organs. The endocrine fibroblast growth factors (FGFs) and Klotho gene families are complex systems that co-evolved with the endoskeleton. In particular, FGF23 and αKlotho which are primarily derived from bone and kidney respectively, are critical in maintaining mineral metabolism where each of these proteins serving highly diverse roles; abound with many unanswered questions regarding their upstream regulation and downstream functions. Genetic lesions of components of this network produce discreet disturbances in many facets of mineral metabolism. One acquired condition with colossal elevations of FGF23 and suppression of αKlotho is chronic kidney disease where multiple organ dysfunction contributes to the morbidity and mortality. However, the single most important group of derangements that encompasses the largest breadth of complications is mineral metabolism disorders. Mineral metabolic disorders in CKD impact negatively and significantly on the progression of renal disease as well as extra-renal complications. Knowledge of the origin, nature, and impact of phosphate, FGF23, and αKlotho derangements is pivotal to understanding the pathophysiology and treatment of CKD.
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Affiliation(s)
- Makoto Kuro-O
- Center for Molecular Medicine, Jichi Medical University, Tochigi, Japan; Department of Pathology, University of Texas Southwestern Medical Center, Dallas, TX, USA; Charles and Jane Pak Center of Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX, USA.
| | - Orson W Moe
- 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; Charles and Jane Pak Center of Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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33
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Lee GJ, Mossa-Al Hashimi L, Debnam ES, Unwin RJ, Marks J. Postprandial adjustments in renal phosphate excretion do not involve a gut-derived phosphaturic factor. Exp Physiol 2017; 102:462-474. [PMID: 28130860 DOI: 10.1113/ep086062] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2016] [Accepted: 01/16/2017] [Indexed: 12/20/2022]
Abstract
NEW FINDINGS What is the central question of this study? Does a previously hypothesized signalling mechanism, believed to detect postprandial increases in intestinal phosphate and that can stimulate the kidneys to rapidly excrete phosphate, operate under physiological conditions? What is the main finding and its importance? Contrary to earlier reports, rapid signalling between the small intestine and kidney mediated by a gut-derived phosphaturic factor in response to a physiological intestinal phosphate load is not supported by the present findings; moreover, hyperphosphataemia and increased parathyroid hormone concentrations are likely to be the underlying factors responsible for the phosphaturia following a supraphysiological intestinal phosphate load. To date, the role of the small intestine in the regulation of postprandial phosphate homeostasis has remained unclear and controversial. Previous studies have proposed the presence of a gut-derived phosphaturic factor that acts independently of changes in plasma phosphate concentration or parathyroid hormone (PTH) concentration; however, these early studies used duodenal luminal phosphate concentrations in the molar range, and therefore, the physiological relevance of this is uncertain. In the present study, we used both in vivo and in vitro approaches to investigate the presence of this putative 'intestinal phosphatonin'. Instillation of 1.3 m phosphate into the duodenum rapidly induced phosphaturia, but in contrast to previous reports, this was associated with significant hyperphosphataemia and elevated PTH concentration; however, there was not the expected decrease in abundance of the renal sodium-phosphate cotransporter NaPi-IIa. Instillation of a physiological (10 mm) phosphate load had no effect on plasma phosphate concentration, PTH concentration or phosphate excretion. Moreover, phosphate uptake by opossum kidney cells was unaffected after incubation with serosal fluid collected from intestinal segments perfused with different concentrations of phosphate. Taken together, these findings do not support the concept of a gut-derived phosphaturic factor that can mediate rapid signalling between the gut and kidney, leading to increased urinary phosphate excretion, as part of normal phosphate homeostasis.
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Affiliation(s)
- Grace J Lee
- Centre for Nephrology, University College London, London, NW3 2PF, UK
| | - Lina Mossa-Al Hashimi
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, NW3 2PF, UK
| | - Edward S Debnam
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, NW3 2PF, UK
| | - Robert J Unwin
- Centre for Nephrology, University College London, London, NW3 2PF, UK.,Department of Neuroscience, Physiology and Pharmacology, University College London, London, NW3 2PF, UK
| | - Joanne Marks
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, NW3 2PF, UK
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Fujii O, Tatsumi S, Ogata M, Arakaki T, Sakaguchi H, Nomura K, Miyagawa A, Ikuta K, Hanazaki A, Kaneko I, Segawa H, Miyamoto KI. Effect of Osteocyte-Ablation on Inorganic Phosphate Metabolism: Analysis of Bone-Kidney-Gut Axis. Front Endocrinol (Lausanne) 2017; 8:359. [PMID: 29312149 PMCID: PMC5742590 DOI: 10.3389/fendo.2017.00359] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 12/11/2017] [Indexed: 01/24/2023] Open
Abstract
In response to kidney damage, osteocytes increase the production of several hormones critically involved in mineral metabolism. Recent studies suggest that osteocyte function is altered very early in the course of chronic kidney disease. In the present study, to clarify the role of osteocytes and the canalicular network in mineral homeostasis, we performed four experiments. In Experiment 1, we investigated renal and intestinal Pi handling in osteocyte-less (OCL) model mice [transgenic mice with the dentin matrix protein-1 promoter-driven diphtheria toxin (DT)-receptor that were injected with DT]. In Experiment 2, we administered granulocyte colony-stimulating factor to mice to disrupt the osteocyte canalicular network. In Experiment 3, we investigated the role of osteocytes in dietary Pi signaling. In Experiment 4, we analyzed gene expression level fluctuations in the intestine and liver by comparing mice fed a high Pi diet and OCL mice. Together, the findings of these experiments indicate that osteocyte ablation caused rapid renal Pi excretion (P < 0.01) before the plasma fibroblast growth factor 23 (FGF23) and parathyroid hormone (PTH) levels increased. At the same time, we observed a rapid suppression of renal Klotho (P < 0.01), type II sodium phosphate transporters Npt2a (P < 0.01) and Npt2c (P < 0.05), and an increase in intestinal Npt2b (P < 0.01) protein. In OCL mice, Pi excretion in feces was markedly reduced (P < 0.01). Together, these effects of osteocyte ablation are predicted to markedly increase intestinal Pi absorption (P < 0.01), thus suggesting that increased intestinal Pi absorption stimulates renal Pi excretion in OCL mice. In addition, the ablation of osteocytes and feeding of a high Pi diet affected FGF15/bile acid metabolism and controlled Npt2b expression. In conclusion, OCL mice exhibited increased renal Pi excretion due to enhanced intestinal Pi absorption. We discuss the role of FGF23-Klotho on renal and intestinal Pi metabolism in OCL mice.
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Affiliation(s)
- Osamu Fujii
- Department of Molecular Nutrition, Institution of Biomedical Science, Tokushima University Graduate School, Tokushima, Japan
| | - Sawako Tatsumi
- Department of Molecular Nutrition, Institution of Biomedical Science, Tokushima University Graduate School, Tokushima, Japan
- *Correspondence: Sawako Tatsumi, ; Ken-ichi Miyamoto,
| | - Mao Ogata
- Department of Molecular Nutrition, Institution of Biomedical Science, Tokushima University Graduate School, Tokushima, Japan
| | - Tomohiro Arakaki
- Department of Molecular Nutrition, Institution of Biomedical Science, Tokushima University Graduate School, Tokushima, Japan
| | - Haruna Sakaguchi
- Department of Molecular Nutrition, Institution of Biomedical Science, Tokushima University Graduate School, Tokushima, Japan
| | - Kengo Nomura
- Department of Molecular Nutrition, Institution of Biomedical Science, Tokushima University Graduate School, Tokushima, Japan
| | - Atsumi Miyagawa
- Department of Molecular Nutrition, Institution of Biomedical Science, Tokushima University Graduate School, Tokushima, Japan
| | - Kayo Ikuta
- Department of Molecular Nutrition, Institution of Biomedical Science, Tokushima University Graduate School, Tokushima, Japan
| | - Ai Hanazaki
- Department of Molecular Nutrition, Institution of Biomedical Science, Tokushima University Graduate School, Tokushima, Japan
| | - Ichiro Kaneko
- Department of Molecular Nutrition, Institution of Biomedical Science, Tokushima University Graduate School, Tokushima, Japan
| | - Hiroko Segawa
- Department of Molecular Nutrition, Institution of Biomedical Science, Tokushima University Graduate School, Tokushima, Japan
| | - Ken-ichi Miyamoto
- Department of Molecular Nutrition, Institution of Biomedical Science, Tokushima University Graduate School, Tokushima, Japan
- *Correspondence: Sawako Tatsumi, ; Ken-ichi Miyamoto,
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Thomas L, Bettoni C, Knöpfel T, Hernando N, Biber J, Wagner CA. Acute Adaption to Oral or Intravenous Phosphate Requires Parathyroid Hormone. J Am Soc Nephrol 2016; 28:903-914. [PMID: 28246304 DOI: 10.1681/asn.2016010082] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 08/22/2016] [Indexed: 12/17/2022] Open
Abstract
Phosphate (Pi) homeostasis is regulated by renal, intestinal, and endocrine mechanisms through which Pi intake stimulates parathyroid hormone (PTH) and fibroblast growth factor-23 secretion, increasing phosphaturia. Mechanisms underlying the early adaptive phase and the role of the intestine, however, remain ill defined. We investigated mineral, endocrine, and renal responses during the first 4 hours after intravenous and intragastric Pi loading in rats. Intravenous Pi loading (0.5 mmol) caused a transient rise in plasma Pi levels and creatinine clearance and an increase in phosphaturia within 10 minutes. Plasma calcium levels fell and PTH levels increased within 10 minutes and remained low or high, respectively. Fibroblast growth factor-23, 1,25-(OH)2-vitamin D3, and insulin concentrations did not respond, but plasma dopamine levels increased by 4 hours. In comparison, gastric Pi loading elicited similar but delayed phosphaturia and endocrine responses but did not affect plasma mineral levels. Either intravenous or gastric loading led to decreased expression and activity of renal Pi transporters after 4 hours. In parathyroidectomized rats, however, only intravenous Pi loading caused phosphaturia, which was blunted and transient compared with that in intact rats. Intravenous but not gastric Pi loading in parathyroidectomized rats also led to higher creatinine clearance and lower plasma calcium levels but did not reduce the expression or activity of Pi transporters. This evidence suggests that an intravenous or intestinal Pi bolus causes rapid phosphaturia through mechanisms requiring PTH and downregulation of renal Pi transporters but does not support a role of the intestine in stimulating renal clearance of Pi.
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Affiliation(s)
- Linto Thomas
- Institute of Physiology, University of Zurich, Zurich, Switzerland; and National Centre for Competence in Research, Zurich, Switzerland
| | - Carla Bettoni
- Institute of Physiology, University of Zurich, Zurich, Switzerland; and National Centre for Competence in Research, Zurich, Switzerland
| | - Thomas Knöpfel
- Institute of Physiology, University of Zurich, Zurich, Switzerland; and National Centre for Competence in Research, Zurich, Switzerland
| | - Nati Hernando
- Institute of Physiology, University of Zurich, Zurich, Switzerland; and National Centre for Competence in Research, Zurich, Switzerland
| | - Jürg Biber
- Institute of Physiology, University of Zurich, Zurich, Switzerland; and National Centre for Competence in Research, Zurich, Switzerland
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland; and National Centre for Competence in Research, Zurich, Switzerland
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Geddes RF, Biourge V, Chang Y, Syme HM, Elliott J. The Effect of Moderate Dietary Protein and Phosphate Restriction on Calcium-Phosphate Homeostasis in Healthy Older Cats. J Vet Intern Med 2016; 30:1690-1702. [PMID: 27527663 PMCID: PMC5032885 DOI: 10.1111/jvim.14563] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Revised: 06/25/2016] [Accepted: 07/18/2016] [Indexed: 12/12/2022] Open
Abstract
Background Dietary phosphate and protein restriction decreases plasma PTH and FGF‐23 concentrations and improves survival time in azotemic cats, but has not been examined in cats that are not azotemic. Hypothesis Feeding a moderately protein‐ and phosphate‐restricted diet decreases PTH and FGF‐23 in healthy older cats and thereby slows progression to azotemic CKD. Animals A total of 54 healthy, client‐owned cats (≥ 9 years). Methods Prospective double‐blinded randomized placebo‐controlled trial. Cats were assigned to test diet (protein 76 g/Mcal and phosphate 1.6 g/Mcal) or control diet (protein 86 g/Mcal and phosphate 2.6 g/Mcal) and monitored for 18 months. Changes in variables over time and effect of diet were assessed by linear mixed models. Results A total of 26 cats ate test diet and 28 cats ate control diet. There was a significant effect of diet on urinary fractional excretion of phosphate (P = 0.045), plasma PTH (P = 0.005), and ionized calcium concentrations (P = 0.018), but not plasma phosphate, FGF‐23, or creatinine concentrations. Plasma PTH concentrations did not significantly change in cats fed the test diet (P = 0.62) but increased over time in cats fed the control diet (P = 0.001). There was no significant treatment effect of the test diet on development of azotemic CKD (3 of 26 (12%) test versus 3 of 28 (11%) control, odds ratio 1.09 (95% CI 0.13–8.94), P = 0.92). Conclusions and Clinical Importance Feeding a moderately protein‐ and phosphate‐restricted diet has effects on calcium‐phosphate homeostasis in healthy older cats and is well tolerated. This might have an impact on renal function and could be useful in early chronic kidney disease.
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Affiliation(s)
- R F Geddes
- Department of Clinical Science and Services, Royal Veterinary College, North Mymms, Hatfield, UK.
| | | | - Y Chang
- Department of Comparative Biological Sciences, Royal Veterinary College, Camden, London, UK
| | - H M Syme
- Department of Clinical Science and Services, Royal Veterinary College, North Mymms, Hatfield, UK
| | - J Elliott
- Department of Comparative Biological Sciences, Royal Veterinary College, Camden, London, UK
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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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Tatsumi S, Miyamoto KI. Regulation of inorganic phosphate ion homeostasis: crosstalk kidney and other organs. Nihon Yakurigaku Zasshi 2016; 147:84-8. [PMID: 26860647 DOI: 10.1254/fpj.147.84] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Tatsumi S, Miyagawa A, Kaneko I, Shiozaki Y, Segawa H, Miyamoto KI. Regulation of renal phosphate handling: inter-organ communication in health and disease. J Bone Miner Metab 2016; 34:1-10. [PMID: 26296817 DOI: 10.1007/s00774-015-0705-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 07/16/2015] [Indexed: 01/18/2023]
Abstract
In this review, we focus on the interconnection of inorganic phosphate (Pi) homeostasis in the network of the bone-kidney, parathyroid-kidney, intestine-kidney, and liver-kidney axes. Such a network of organ communication is important for body Pi homeostasis. Normalization of serum Pi levels is a clinical target in patients with chronic kidney disease (CKD). Particularly, disorders of the fibroblast growth factor 23/klotho system are observed in early CKD. Identification of phosphaturic factors from the intestine and liver may enhance our understanding of body Pi homeostasis and Pi metabolism disturbances in CKD patients.
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Affiliation(s)
- Sawako Tatsumi
- Department of Molecular Nutrition, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15 Kuramoto-cho, Tokushima, 770-8503, Japan
| | - Atsumi Miyagawa
- Department of Molecular Nutrition, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15 Kuramoto-cho, Tokushima, 770-8503, Japan
| | - Ichiro Kaneko
- Department of Molecular Nutrition, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15 Kuramoto-cho, Tokushima, 770-8503, Japan
| | - Yuji Shiozaki
- Department of Molecular Nutrition, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15 Kuramoto-cho, Tokushima, 770-8503, Japan
| | - Hiroko Segawa
- Department of Molecular Nutrition, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15 Kuramoto-cho, Tokushima, 770-8503, Japan
| | - Ken-Ichi Miyamoto
- Department of Molecular Nutrition, Institute of Biomedical Sciences, Tokushima University Graduate School, 3-18-15 Kuramoto-cho, Tokushima, 770-8503, Japan.
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Felsenfeld AJ, Levine BS, Rodriguez M. Pathophysiology of Calcium, Phosphorus, and Magnesium Dysregulation in Chronic Kidney Disease. Semin Dial 2015; 28:564-77. [DOI: 10.1111/sdi.12411] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Arnold J. Felsenfeld
- Department of Medicine; VA Greater Los Angeles Healthcare System and the David Geffen School of Medicine at UCLA; Los Angeles California
| | - Barton S. Levine
- Department of Medicine; VA Greater Los Angeles Healthcare System and the David Geffen School of Medicine at UCLA; Los Angeles California
| | - Mariano Rodriguez
- Nephrology Service; IMIBIC; Hospital Universitario Reina Sofia; University of Cordoba; Cordoba Spain
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41
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Goldsweig BK, Carpenter TO. Hypophosphatemic rickets: lessons from disrupted FGF23 control of phosphorus homeostasis. Curr Osteoporos Rep 2015; 13:88-97. [PMID: 25620749 DOI: 10.1007/s11914-015-0259-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Fibroblast growth factor-23 (FGF23) regulates phosphate reabsorption in the kidney and therefore plays an essential role in phosphate balance in humans. There is a host of defects that ultimately lead to excess FGF23 levels and thereby cause renal phosphate wasting and hypophosphatemic rickets. We describe the genetic, pathophysiologic, and clinical aspects of this group of disorders with a focus on X-linked hypophosphatemia (XLH), the best characterized of these abnormalities. We also discuss autosomal dominant hypophosphatemic rickets (ADHR), autosomal recessive hypophosphatemic rickets (ARHR) and tumor-induced osteomalacia (TIO) in addition to other rarer FGF23-mediated conditions. We contrast the FGF23-mediated disorders with FGF23-independent hypophosphatemia, specifically hypophosphatemic rickets with hypercalciuria (HHRH). Errant diagnosis of hypophosphatemic disorders is common. This review aims to enhance the recognition and appropriate diagnosis of hypophosphatemia and to guide appropriate treatment.
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Affiliation(s)
- Bracha K Goldsweig
- Department of Pediatrics (Endocrinology), Yale University School of Medicine, 333 Cedar Street, PO Box 208064, New Haven, CT, 06520, USA,
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Régulation de la phosphatémie: insuffisance rénale chronique et nouveaux facteurs l’influençant tels que le FGF23 (Fibroblast Growth Factor 23) et klotho. Nephrol Ther 2015; 11:125-8. [DOI: 10.1016/j.nephro.2015.03.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Intestinal phosphate transport: a therapeutic target in chronic kidney disease and beyond? Pediatr Nephrol 2015; 30:363-71. [PMID: 24496589 DOI: 10.1007/s00467-014-2759-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 12/11/2013] [Accepted: 01/08/2014] [Indexed: 12/22/2022]
Abstract
Hyperphosphatemia is a serious complication of late-stage chronic kidney disease (CKD), contributing to the increased cardiovascular morbidity and mortality seen in this patient group. Results from retrospective studies suggest that small increases in serum phosphate concentration, within the normal or near-normal range, also correlate with increased cardiovascular morbidity and mortality and have led to the suggestion that detection and preventative treatment of positive phosphate balance is important in healthy individuals as well as in those with CKD. Phosphate homeostasis is maintained by the crosstalk between intestinal phosphate absorption and renal phosphate excretion; however, relatively little is known about the mechanisms of intestinal phosphate transport. Our current understanding is that the intestinal type II sodium phosphate cotransporter, NaPi-IIb, plays a significant role in absorption. It may also be involved in the sensing of dietary phosphate composition and the release of hormonal factors that modulate renal phosphate reabsorption to achieve phosphate balance. Interestingly, studies using NaPi-IIb knockout mice with adenine-induced CKD show only partial attenuation of hyperphosphatemia, suggesting that an additional sodium-independent pathway is involved in phosphate absorption. The aim of this review is to discuss our current knowledge of the processes and role of the intestine in phosphate homeostasis and to provide evidence that this organ could be targeted for the treatment of hypophosphatemia and hyperphosphatemia.
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Marks J, Lee GJ, Nadaraja SP, Debnam ES, Unwin RJ. Experimental and regional variations in Na+-dependent and Na+-independent phosphate transport along the rat small intestine and colon. Physiol Rep 2015; 3:3/1/e12281. [PMID: 25626876 PMCID: PMC4387749 DOI: 10.14814/phy2.12281] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Despite the importance of extracellular phosphate in many essential biological processes, the mechanisms of phosphate transport across the epithelium of different intestinal segments remain unclear. We have used an in vitro method to investigate phosphate transport at the brush border membrane (BBM) of intact intestinal segments and an in vivo method to study transepithelial phosphate absorption. We have used micromolar phosphate concentrations known to favor NaPi‐IIb‐mediated transport, and millimolar concentrations that are representative of the levels we have measured in luminal contents, to compare the extent of Na+‐dependent and Na+‐independent phosphate transport along the rat duodenum, jejunum, ileum, and proximal and distal colon. Our findings confirm that overall the jejunum is the main site of phosphate absorption; however, at millimolar concentrations, absorption shows ~30% Na+‐dependency, suggesting that transport is unlikely to be mediated exclusively by the Na+‐dependent NaPi‐IIb co‐transporter. In the ileum, studies in vitro confirmed that relatively low levels of phosphate transport occur at the BBM of this segment, although significant Na+‐dependent transport was detected using millimolar levels of phosphate in vivo. Since NaPi‐IIb protein is not detectable at the rat ileal BBM, our data suggest the presence of an as yet unidentified Na+‐dependent uptake pathway in this intestinal segment in vivo. In addition, we have confirmed that the colon has a significant capacity for phosphate absorption. Overall, this study highlights the complexities of intestinal phosphate absorption that can be revealed using different phosphate concentrations and experimental techniques. We have used in vitro and in vivo methods to investigate phosphate absorption in different regions of the rat small and large intestine at micromolar and millimolar phosphate concentrations. Our findings confirm that overall the jejunum is the main site of phosphate absorption but at millimolar concentrations phosphate absorption also occurs in the ileum and colon. Overall, this study highlights the complexities of intestinal phosphate absorption that can be revealed using different phosphate concentrations and experimental techniques.
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Affiliation(s)
- Joanne Marks
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, UK
| | - Grace J Lee
- UCL Centre for Nephrology, University College London, London, UK
| | - Sobiya P Nadaraja
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, UK
| | - Edward S Debnam
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, UK UCL Centre for Nephrology, University College London, London, UK
| | - Robert J Unwin
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, UK UCL Centre for Nephrology, University College London, London, UK
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Shaman AM, Kowalski SR. Hyperphosphatemia Management in Patients with Chronic Kidney Disease. Saudi Pharm J 2015; 24:494-505. [PMID: 27330380 PMCID: PMC4908098 DOI: 10.1016/j.jsps.2015.01.009] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 01/01/2015] [Indexed: 01/07/2023] Open
Abstract
Hyperphosphatemia in chronic kidney disease (CKD) patients is a potentially life altering condition that can lead to cardiovascular calcification, metabolic bone disease (renal osteodystrophy) and the development of secondary hyperparathyroidism (SHPT). It is also associated with increased prevalence of cardiovascular diseases and mortality rates. To effectively manage hyperphosphatemia in CKD patients it is important to not only consider pharmacological and nonpharmacological treatment options but also to understand the underlying physiologic pathways involved in phosphorus homoeostasis. This review will therefore provide both a background into phosphorus homoeostasis and the management of hyperphosphatemia in CKD patients. In addition, it will cover some of the most important reasons for failure to control hyperphosphatemia with emphasis on the effect of the gastric pH on phosphate binders efficiency.
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Affiliation(s)
- Ahmed M Shaman
- Department of Clinical Pharmacy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Stefan R Kowalski
- School of Pharmacy and Medical Sciences, University of South Australia, South Australia, Australia
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Kumar R, Folpe AL, Mullan BP. Tumor-Induced Osteomalacia. TRANSLATIONAL ENDOCRINOLOGY & METABOLISM 2015; 7:1871. [PMID: 26478788 PMCID: PMC4605441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Affiliation(s)
- Rajiv Kumar
- Division of Nephrology and Hypertension, Mayo Clinic, 200 First Street Southwest, Rochester, MN 55905 ; Division of Endocrinology, Metabolism, Diabetes and Nutrition, Mayo Clinic, 200 First Street Southwest, Rochester, MN 55905 ; Department of Internal Medicine, Mayo Clinic, 200 First Street Southwest, Rochester, MN 55905 ; Department of Biochemistry and Molecular Biology, Mayo Clinic, 200 First Street Southwest, Rochester, MN 55905
| | - Andrew L Folpe
- Department of Laboratory Medicine and Pathology, Mayo Clinic, 200 First Street Southwest, Rochester, MN 55905
| | - Brian P Mullan
- Department of Radiology, Mayo Clinic, 200 First Street Southwest, Rochester, MN 55905
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Abstract
Recent studies of inherited disorders of phosphate metabolism have shed new light on the understanding of phosphate metabolism. Phosphate has important functions in the body and several mechanisms have evolved to regulate phosphate balance including vitamin D, parathyroid hormone and phosphatonins such as fibroblast growth factor-23 (FGF23). Disorders of phosphate homeostasis leading to hypo- and hyperphosphataemia are common and have clinical and biochemical consequences. Notably, recent studies have linked hyperphosphataemia with an increased risk of cardiovascular disease. This review outlines the recent advances in the understanding of phosphate homeostasis and describes the causes, investigation and management of hypo- and hyperphosphataemia.
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Affiliation(s)
- P Manghat
- Department of Chemical Pathology, Darent Valley Hospital, Dartford, UK
| | - R Sodi
- Department of Biochemistry, NHS Lanarkshire, East Kilbride, UK
| | - R Swaminathan
- Department of Chemical Pathology, St. Thomas Hospital, London, UK
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48
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Ix JH, Anderson CAM, Smits G, Persky MS, Block GA. Effect of dietary phosphate intake on the circadian rhythm of serum phosphate concentrations in chronic kidney disease: a crossover study. Am J Clin Nutr 2014; 100:1392-7. [PMID: 25332338 PMCID: PMC4196488 DOI: 10.3945/ajcn.114.085498] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Previous trials of binders in chronic kidney disease (CKD) stages 3-5 have shown only modest changes in serum phosphate but evaluated morning phosphate. It is unknown whether a circadian pattern of phosphate concentrations exists in CKD and is modifiable by dietary manipulation. OBJECTIVES We determined the circadian pattern of serum phosphate concentrations in CKD and whether it was modifiable by altering absorbable phosphate. DESIGN This was a crossover feeding study in 11 CKD participants (estimated glomerular filtration rate: 30-45 mL · min(-1) · 1.73 m(-2)) and 4 healthy control subjects. All subjects received high-phosphate (2500 mg/d), normal-phosphate (1500 mg/d), and low-phosphate (1000 mg/d plus 1000 mg lanthanum carbonate 3 times/d) diets for 5 d followed by a 10-d washout. After each 5-d feed, phosphate and other measurements were made every 4 h over 1 day. RESULTS In CKD participants who consumed the high-phosphate diet, there were circadian changes in phosphate with lowest concentrations (± SDs) at 0800 (4.2 ± 0.5 mg/dL) and 2 peaks at 1600 and 0400 (4.5 ± 0.8 and 4.4 ± 0.6 mg/dL, respectively), which were similar to those in healthy controls. Results with the normal-phosphate diet were similar. The low-phosphate diet altered the circadian rhythm (P = 0.02) such that 0400 and 1600 peaks were absent. Differences in phosphate for lowest- compared with highest-phosphate diets were smallest at 0800 and largest at 1600 (0.5 compared with 1.0 mg/dL) in CKD. Circadian changes in phosphate were not explained by urine phosphate excretion, parathyroid hormone, or fibroblast growth factor-23. CONCLUSIONS A circadian pattern of serum phosphate is observed in CKD with lowest concentrations at 0800 and highest at 1600 and 0400. This circadian pattern is modifiable by phosphate intake and most evident at 1600. Future intervention studies targeting intestinal phosphate absorption should consider afternoon phosphate measurements.
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Affiliation(s)
- Joachim H Ix
- From the Division of Nephrology, Department of Medicine (JHI) and Division of Preventive Medicine, Department of Family and Preventive Medicine, University of California San Diego, San Diego, CA (JHI and CAMA); the Nephrology Section, Veterans Affairs San Diego Healthcare System, San Diego, CA (JHI); and Denver Nephrology, Denver, CO (GS, MSP, and GAB)
| | - Cheryl A M Anderson
- From the Division of Nephrology, Department of Medicine (JHI) and Division of Preventive Medicine, Department of Family and Preventive Medicine, University of California San Diego, San Diego, CA (JHI and CAMA); the Nephrology Section, Veterans Affairs San Diego Healthcare System, San Diego, CA (JHI); and Denver Nephrology, Denver, CO (GS, MSP, and GAB)
| | - Gerard Smits
- From the Division of Nephrology, Department of Medicine (JHI) and Division of Preventive Medicine, Department of Family and Preventive Medicine, University of California San Diego, San Diego, CA (JHI and CAMA); the Nephrology Section, Veterans Affairs San Diego Healthcare System, San Diego, CA (JHI); and Denver Nephrology, Denver, CO (GS, MSP, and GAB)
| | - Martha S Persky
- From the Division of Nephrology, Department of Medicine (JHI) and Division of Preventive Medicine, Department of Family and Preventive Medicine, University of California San Diego, San Diego, CA (JHI and CAMA); the Nephrology Section, Veterans Affairs San Diego Healthcare System, San Diego, CA (JHI); and Denver Nephrology, Denver, CO (GS, MSP, and GAB)
| | - Geoffrey A Block
- From the Division of Nephrology, Department of Medicine (JHI) and Division of Preventive Medicine, Department of Family and Preventive Medicine, University of California San Diego, San Diego, CA (JHI and CAMA); the Nephrology Section, Veterans Affairs San Diego Healthcare System, San Diego, CA (JHI); and Denver Nephrology, Denver, CO (GS, MSP, and GAB)
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Chang AR, Grams ME. Serum phosphorus and mortality in the Third National Health and Nutrition Examination Survey (NHANES III): effect modification by fasting. Am J Kidney Dis 2014; 64:567-73. [PMID: 24935232 DOI: 10.1053/j.ajkd.2014.04.028] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Accepted: 04/22/2014] [Indexed: 12/13/2022]
Abstract
BACKGROUND Serum phosphorus levels have been associated with mortality in some but not all studies. Because dietary intake prior to measurement can affect serum phosphorus levels, we hypothesized that the association between serum phosphorus level and mortality is strongest in those who have fasted longer. STUDY DESIGN Prospective cohort study. SETTING & PARTICIPANTS Nationally representative sample of 12,984 participants 20 years or older in the Third National Health and Nutrition Examination Survey (1988-1994). FACTORS Serum phosphorus level, fasting duration (dichotomized as ≥ 12 or < 12 hours). OUTCOMES All-cause and cardiovascular mortality determined by death certificate data from the National Death Index. MEASUREMENTS Serum phosphorus measured in a central laboratory and fasting duration recorded as time since food or drink other than water was consumed. RESULTS Individuals fasting 12 or more hours had lower serum phosphorus levels than those fasting less than 12 hours (3.34 vs 3.55 mg/dL; P < 0.001) and higher correlation with repeat measurement (0.66 vs 0.53; P = 0.002). In multivariable-adjusted Cox regression models, the highest quartile of serum phosphorus was associated with increased mortality in participants fasting 12 or more hours (adjusted HR, 1.74; 95% CI, 1.38-2.20; reference, lowest quartile) but not in participants fasting less than 12 hours (adjusted HR, 1.08; 95% CI, 0.89-1.32; P for interaction = 0.002). Relationships were consistent using 8 hours as the fasting cutoff point or cardiovascular mortality as the outcome. LIMITATIONS Observational study, lack of fibroblast growth factor 23 or intact parathyroid hormone measurements. CONCLUSIONS Fasting but not nonfasting serum phosphorus levels were associated with increased mortality. Risk prognostication based on serum phosphorus may be improved using fasting levels.
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Affiliation(s)
- Alex R Chang
- Division of Nephrology, Geisinger Health System, Danville, PA.
| | - Morgan E Grams
- Division of Nephrology, Johns Hopkins University, Baltimore, MD; Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins University, Baltimore, MD
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50
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Scanni R, vonRotz M, Jehle S, Hulter HN, Krapf R. The human response to acute enteral and parenteral phosphate loads. J Am Soc Nephrol 2014; 25:2730-9. [PMID: 24854273 DOI: 10.1681/asn.2013101076] [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] [Indexed: 12/16/2022] Open
Abstract
The human response to acute phosphate (PO4) loading is poorly characterized, and it is unknown whether an intestinal phosphate sensor mechanism exists. Here, we characterized the human mineral and endocrine response to parenteral and duodenal acute phosphate loads. Healthy human participants underwent 36 hours of intravenous (IV; 1.15 [low dose] and 2.30 [high dose] mmol of PO4/kg per 24 hours) or duodenal (1.53 mmol of PO4/kg per 24 hours) neutral sodium PO4 loading. Control experiments used equimolar NaCl loads. Maximum PO4 urinary excretory responses occurred between 12 and 24 hours and were similar for low-dose IV and duodenal infusion. Hyperphosphatemic responses were also temporally and quantitatively similar for low-dose IV and duodenal PO4 infusion. Fractional renal PO4 clearance increased approximately 6-fold (high-dose IV group) and 4-fold (low-dose IV and duodenal groups), and significant reductions in plasma PO4 concentrations relative to peak values occurred by 36 hours, despite persistent PO4 loading. After cessation of loading, frank hypophosphatemia occurred. The earliest phosphaturic response occurred after plasma PO4 and parathyroid hormone concentrations increased. Plasma fibroblast growth factor-23 concentration increased after the onset of phosphaturia, followed by a decrease in plasma 1,25(OH)2D levels; α-Klotho levels did not change. Contrary to results in rodents, we found no evidence for intestinal-specific phosphaturic control mechanisms in humans. Complete urinary phosphate recovery in the IV loading groups provides evidence against any important extrarenal response to acute PO4 loads.
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Affiliation(s)
- Roberto Scanni
- Medizinische Universitätsklinik, Kantonsspital Bruderholz, University of Basel, Basel, Switzerland; and
| | - Matthias vonRotz
- Medizinische Universitätsklinik, Kantonsspital Bruderholz, University of Basel, Basel, Switzerland; and
| | - Sigrid Jehle
- Medizinische Universitätsklinik, Kantonsspital Bruderholz, University of Basel, Basel, Switzerland; and
| | - Henry N Hulter
- Department of Medicine, University of California, San Francisco, San Francisco, California
| | - Reto Krapf
- Medizinische Universitätsklinik, Kantonsspital Bruderholz, University of Basel, Basel, Switzerland; and
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