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Abstract
Phosphate is an essential nutrient for life and is a critical component of bone formation, a major signaling molecule, and structural component of cell walls. Phosphate is also a component of high-energy compounds (i.e., AMP, ADP, and ATP) and essential for nucleic acid helical structure (i.e., RNA and DNA). Phosphate plays a central role in the process of mineralization, normal serum levels being associated with appropriate bone mineralization, while high and low serum levels are associated with soft tissue calcification. The serum concentration of phosphate and the total body content of phosphate are highly regulated, a process that is accomplished by the coordinated effort of two families of sodium-dependent transporter proteins. The three isoforms of the SLC34 family (SLC34A1-A3) show very restricted tissue expression and regulate intestinal absorption and renal excretion of phosphate. SLC34A2 also regulates the phosphate concentration in multiple lumen fluids including milk, saliva, pancreatic fluid, and surfactant. Both isoforms of the SLC20 family exhibit ubiquitous expression (with some variation as to which one or both are expressed), are regulated by ambient phosphate, and likely serve the phosphate needs of the individual cell. These proteins exhibit similarities to phosphate transporters in nonmammalian organisms. The proteins are nonredundant as mutations in each yield unique clinical presentations. Further research is essential to understand the function, regulation, and coordination of the various phosphate transporters, both the ones described in this review and the phosphate transporters involved in intracellular transport.
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Affiliation(s)
- Nati Hernando
- University of Zurich-Irchel, Institute of Physiology, Zurich, Switzerland; Department of Medicine, University of Louisville School of Medicine, Louisville, Kentucky; and Robley Rex VA Medical Center, Louisville, Kentucky
| | - Kenneth Gagnon
- University of Zurich-Irchel, Institute of Physiology, Zurich, Switzerland; Department of Medicine, University of Louisville School of Medicine, Louisville, Kentucky; and Robley Rex VA Medical Center, Louisville, Kentucky
| | - Eleanor Lederer
- University of Zurich-Irchel, Institute of Physiology, Zurich, Switzerland; Department of Medicine, University of Louisville School of Medicine, Louisville, Kentucky; and Robley Rex VA Medical Center, Louisville, Kentucky
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2
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Calcium-Phosphate Metabolism Disorders in Patients with Renal Failure Clinical Significance, Diagnosis and Treatment. ACTA MEDICA BULGARICA 2019. [DOI: 10.2478/amb-2019-0009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
Chronic kidney diseases (CKD) are commonly associated with calcium and phosphorus metabolism disorders. The general term of “renal osteodystrophy” (ROD) encompasses a complex spectrum of abnormalities in bone and mineral metabolism in CKD. This is one of the most serious and debilitating complications of CKD. It is related to disproportionately high direct and indirect costs of healthcare, thus posing a major burden on society. The development of ROD begins too early in the course of CKD. Some mechanisms involved in the pathogenesis of ROD are reduced calciferol production, calcium deficiency and hyperphosphatemia. Clinically, ROD occurs with varied manifestations – osteomalacia, osteoporosis, adynamic bone disease. The diagnosis and the treatment are a challenge for the physician and effort should be made to prolong the duration and quality of life of the affected patients.
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Bajwa NM, Sanchez CP, Lindsey RC, Watt H, Mohan S. Cortical and trabecular bone are equally affected in rats with renal failure and secondary hyperparathyroidism. BMC Nephrol 2018; 19:24. [PMID: 29394885 PMCID: PMC5796449 DOI: 10.1186/s12882-018-0822-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 01/21/2018] [Indexed: 12/31/2022] Open
Abstract
Background Changes in mineral metabolism and bone structure develop early in the course of chronic kidney disease and at end-stage are associated with increased risk of fragility fractures. The disruption of phosphorus homeostasis leads to secondary hyperparathyroidism, a common complication of chronic kidney disease. However, the molecular pathways by which high phosphorus influences bone metabolism in the early stages of the disease are not completely understood. We investigated the effects of a high phosphorus diet on bone and mineral metabolism using a 5/6 nephrectomy model of chronic kidney disease. Methods Four-week old rats were randomly assigned into groups: 1) Control with standard diet, 2) Nephrectomy with standard rodent diet, and 3) Nephrectomy with high phosphorus diet. Rats underwent in vivo imaging at baseline, day 14, and day 28, followed by ex vivo imaging. Results Cortical bone density at the femoral mid-diaphysis was reduced in nephrectomy-control and nephrectomy-high phosphorus compared to control rats. In contrast, trabecular bone mass was reduced at both the lumbar vertebrae and the femoral secondary spongiosa in nephrectomy-high phosphorus but not in nephrectomy-control. Reduced trabecular bone volume adjusted for tissue volume was caused by changes in trabecular number and separation at day 35. Histomorphometry revealed increased bone resorption in tibial secondary spongiosa in nephrectomy-control. High phosphorus diet-induced changes in bone microstructure were accompanied by increased serum parathyroid hormone and fibroblast growth factor 23 levels. Conclusion Our study demonstrates that changes in mineral metabolism and hormonal dysfunction contribute to trabecular and cortical bone changes in this model of early chronic kidney disease.
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Affiliation(s)
- Nikita M Bajwa
- Musculoskeletal Disease Center, VA Loma Linda Healthcare System, 11201 Benton Street, Loma Linda, CA, 92357, USA
| | - Cheryl P Sanchez
- Department of Pediatrics, Loma Linda University, Loma Linda, CA, 92354, USA
| | - Richard C Lindsey
- Musculoskeletal Disease Center, VA Loma Linda Healthcare System, 11201 Benton Street, Loma Linda, CA, 92357, USA
| | - Heather Watt
- Musculoskeletal Disease Center, VA Loma Linda Healthcare System, 11201 Benton Street, Loma Linda, CA, 92357, USA
| | - Subburaman Mohan
- Musculoskeletal Disease Center, VA Loma Linda Healthcare System, 11201 Benton Street, Loma Linda, CA, 92357, USA. .,Department of Medicine, Loma Linda University, Loma Linda, CA, 92354, USA. .,Department of Orthopedic Surgery, Loma Linda University, Loma Linda, CA, 92354, USA.
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4
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Heiss C, Kern S, Malhan D, Böcker W, Engelhardt M, Daghma DES, Stoetzel S, Schmitt J, Ivo M, Kauschke V, Lips KS, Tushtev K, Rezwan K, El Khassawna T. A New Clinically Relevant T-Score Standard to Interpret Bone Status in a Sheep Model. Med Sci Monit Basic Res 2017; 23:326-335. [PMID: 28966340 PMCID: PMC5637575 DOI: 10.12659/msmbr.905561] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Background Osteoporosis is diagnosed by bone loss using a radiological parameter called T-score. Preclinical studies use DXA to evaluate bone status were the T-score is referenced on bone mineral density (BMD) values of the same animals before treatment. Clinically, the reference BMD represents values of an independent group of healthy patients around 30 years old. The present study established a clinically similar T-score standard to diagnose osteoporosis in a sheep model. Material/Methods We used 31 female merino land sheep (average 5.5 years old) to study osteoporosis. The following groups were compared using DXA measurement: 1) control; 2) ovariectomized (OVX); 3) OVX combined with a deficient diet (OVXD); and 4) OVXD combined with methylprednisolone administration (OVXDS). Further, an independent group of 32 healthy sheep (4–6 years old) were measured as an independent baseline. BMD was measured at 0 months, 3 months, and 8 months after treatment. Results The same significance pattern between the treated groups and either baseline groups was seen. However, using an independent baseline changed the “clinical” interpretation of the data from an osteoporotic bone status (T-score <−2.5) after 3 months of OXDS treatment into an osteopenic bone status (T-score <−1.5 to −2.4). Conclusions Using an independent baseline enhanced the statistical significance and showed the clinical relevance. Furthermore, an independent baseline is a reliable alternative to use of a new control group for future experiments and thus reduces the number of animals needed by eliminating the need for a control and corresponding to clinical practice.
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Affiliation(s)
- Christian Heiss
- Department of Experimental Trauma Surgery, Faculty of Medicine, Justus-Liebig University, Giessen, Germany
| | - Stefanie Kern
- Department of Experimental Trauma Surgery, Faculty of Medicine, Justus-Liebig University, Giessen, Germany
| | - Deeksha Malhan
- Department of Experimental Trauma Surgery, Faculty of Medicine, Justus-Liebig University, Giessen, Germany
| | - Wolfgang Böcker
- Department of Experimental Trauma Surgery, Faculty of Medicine, Justus-Liebig University, Giessen, Germany.,Department of General, Trauma, and Reconstructive Surgery, Ludwig-Maximilians University, Munich, Germany
| | - Markus Engelhardt
- Department of Experimental Trauma Surgery, Faculty of Medicine, Justus-Liebig University, Giessen, Germany.,Department of Trauma, Hand, and Reconstructive Surgery, University Hospital of Giessen-Marburg, Giessen, Germany
| | - Diaa Eldin S Daghma
- Department of Experimental Trauma Surgery, Faculty of Medicine, Justus-Liebig University, Giessen, Germany
| | - Sabine Stoetzel
- Department of Experimental Trauma Surgery, Faculty of Medicine, Justus-Liebig University, Giessen, Germany
| | - Jakob Schmitt
- Department of Experimental Trauma Surgery, Faculty of Medicine, Justus-Liebig University, Giessen, Germany
| | - Matthias Ivo
- Department of Experimental Trauma Surgery, Faculty of Medicine, Justus-Liebig University, Giessen, Germany
| | - Vivien Kauschke
- Department of Experimental Trauma Surgery, Faculty of Medicine, Justus-Liebig University, Giessen, Germany
| | - Katrin S Lips
- Department of Experimental Trauma Surgery, Faculty of Medicine, Justus-Liebig University, Giessen, Germany
| | - Kamen Tushtev
- Advanced Ceramics, University of Bremen, Bremen, Germany
| | - Kurosch Rezwan
- Advanced Ceramics, University of Bremen, Bremen, Germany
| | - Thaqif El Khassawna
- Department of Experimental Trauma Surgery, Faculty of Medicine, Justus-Liebig University, Giessen, Germany
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El Khassawna T, Böcker W, Brodsky K, Weisweiler D, Govindarajan P, Kampschulte M, Thormann U, Henss A, Rohnke M, Bauer N, Müller R, Deutsch A, Ignatius A, Dürselen L, Langheinrich A, Lips KS, Schnettler R, Heiss C. Impaired extracellular matrix structure resulting from malnutrition in ovariectomized mature rats. Histochem Cell Biol 2015. [PMID: 26210855 DOI: 10.1007/s00418-015-1356-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Bone loss is a symptom related to disease and age, which reflects on bone cells and ECM. Discrepant regulation affects cell proliferation and ECM localization. Rat model of osteoporosis (OVX) was investigated against control rats (Sham) at young and old ages. Biophysical, histological and molecular techniques were implemented to examine the underlying cellular and extracellular matrix changes and to assess the mechanisms contributing to bone loss in the context of aging and the widely used osteoporotic models in rats. Bone loss exhibited a compromised function of bone cells and infiltration of adipocytes into bone marrow. However, the expression of genes regulating collagen catabolic process and adipogenesis was chronologically shifted in diseased bone in comparison with aged bone. The data showed the involvement of Wnt signaling inhibition in adipogenesis and bone loss due to over-expression of SOST in both diseased and aged bone. Further, in the OVX animals, an integrin-mediated ERK activation indicated the role of MAPK in osteoblastogenesis and adipogenesis. The increased PTH levels due to calcium and estrogen deficiency activated osteoblastogenesis. Thusly, RANKL-mediated osteoclastogenesis was initiated. Interestingly, the data show the role of MEPE regulating osteoclast-mediated resorption at late stages in osteoporotic bone. The interplay between ECM and bone cells change tissue microstructure and properties. The involvement of Wnt and MAPK pathways in activating cell proliferation has intriguing similarities to oncogenesis and myeloma. The study indicates the importance of targeting both pathways simultaneously to remedy metabolic bone diseases and age-related bone loss.
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Affiliation(s)
- Thaqif El Khassawna
- Laboratory of Experimental Trauma Surgery, Justus-Liebig University, Giessen, Germany.
| | - Wolfgang Böcker
- Laboratory of Experimental Trauma Surgery, Justus-Liebig University, Giessen, Germany. .,Department of Trauma Surgery, University Hospital of Giessen-Marburg, Rudolf-Buchheim-Strasse 7, 35385, Giessen, Germany.
| | - Katharina Brodsky
- Laboratory of Experimental Trauma Surgery, Justus-Liebig University, Giessen, Germany.
| | - David Weisweiler
- Department of Trauma Surgery, University Hospital of Giessen-Marburg, Rudolf-Buchheim-Strasse 7, 35385, Giessen, Germany.
| | | | - Marian Kampschulte
- Department of Radiology, University Hospital of Giessen-Marburg, Giessen, Germany.
| | - Ulrich Thormann
- Department of Trauma Surgery, University Hospital of Giessen-Marburg, Rudolf-Buchheim-Strasse 7, 35385, Giessen, Germany.
| | - Anja Henss
- Institute for Physical Chemistry, Justus-Liebig-University of Giessen, Giessen, Germany.
| | - Marcus Rohnke
- Institute for Physical Chemistry, Justus-Liebig-University of Giessen, Giessen, Germany.
| | - Natali Bauer
- Department of Veterinary Clinical Sciences, Clinical Pathology and Clinical Pathophysiology, Justus-Liebig University Giessen, Giessen, Germany.
| | - Robert Müller
- Center for Information Services and High Performance Computing, TU Dresden, Dresden, Germany.
| | - Andreas Deutsch
- Center for Information Services and High Performance Computing, TU Dresden, Dresden, Germany.
| | - Anita Ignatius
- Institute of Orthopedic Research and Biomechanics, Centre of Musculoskeletal Research, University of Ulm, Ulm, Germany.
| | - Lutz Dürselen
- Institute of Orthopedic Research and Biomechanics, Centre of Musculoskeletal Research, University of Ulm, Ulm, Germany.
| | - Alexander Langheinrich
- Department of Diagnostic and Interventional Radiology, BG Trauma Hospital Frankfurt/Main, Frankfurt, Germany.
| | - Katrin S Lips
- Laboratory of Experimental Trauma Surgery, Justus-Liebig University, Giessen, Germany.
| | - Reinhard Schnettler
- Laboratory of Experimental Trauma Surgery, Justus-Liebig University, Giessen, Germany. .,Department of Trauma Surgery, University Hospital of Giessen-Marburg, Rudolf-Buchheim-Strasse 7, 35385, Giessen, Germany.
| | - Christian Heiss
- Laboratory of Experimental Trauma Surgery, Justus-Liebig University, Giessen, Germany. .,Department of Trauma Surgery, University Hospital of Giessen-Marburg, Rudolf-Buchheim-Strasse 7, 35385, Giessen, Germany.
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Kelley R, Werdin ES, Bruce AT, Choudhury S, Wallace SM, Ilagan RM, Cox BR, Tatsumi-Ficht P, Rivera EA, Spencer T, Rapoport HS, Wagner BJ, Guthrie K, Jayo MJ, Bertram TA, Presnell SC. Tubular cell-enriched subpopulation of primary renal cells improves survival and augments kidney function in rodent model of chronic kidney disease. Am J Physiol Renal Physiol 2010; 299:F1026-39. [PMID: 20826573 DOI: 10.1152/ajprenal.00221.2010] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Established chronic kidney disease (CKD) may be identified by severely impaired renal filtration that ultimately leads to the need for dialysis or kidney transplant. Dialysis addresses only some of the sequelae of CKD, and a significant gap persists between patients needing transplant and available organs, providing impetus for development of new CKD treatment modalities. Some postulate that CKD develops from a progressive imbalance between tissue damage and the kidney's intrinsic repair and regeneration processes. In this study we evaluated the effect of kidney cells, delivered orthotopically by intraparenchymal injection to rodents 4-7 wk after CKD was established by two-step 5/6 renal mass reduction (NX), on the regeneration of kidney function and architecture as assessed by physiological, tissue, and molecular markers. A proof of concept for the model, cell delivery, and systemic effect was demonstrated with a heterogeneous population of renal cells (UNFX) that contained cells from all major compartments of the kidney. Tubular cells are known contributors to kidney regeneration in situ following acute injury. Initially tested as a control, a tubular cell-enriched subpopulation of UNFX (B2) surprisingly outperformed UNFX. Two independent studies (3 and 6 mo in duration) with B2 confirmed that B2 significantly extended survival and improved renal filtration (serum creatinine and blood urea nitrogen). The specificity of B2 effects was verified by direct comparison to cell-free vehicle controls and an equivalent dose of non-B2 cells. Quantitative histological evaluation of kidneys at 6 mo after treatment confirmed that B2 treatment reduced severity of kidney tissue pathology. Treatment-associated reduction of transforming growth factor (TGF)-β1, plasminogen activator inhibitor (PAI)-1, and fibronectin (FN) provided evidence that B2 cells attenuated canonical pathways of profibrotic extracellular matrix production.
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Affiliation(s)
- Rusty Kelley
- Tengion, Inc., 3929 Westpoint Blvd., Suite G, Winston-Salem, NC 27103, USA
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Abstract
Abnormalities in bone and mineral metabolism have a significant impact on morbidity and mortality among patients with end-stage renal disease (ESRD). In addition to confounding environmental factors, genetic susceptibility factors may also influence the occurrence and severity of these abnormalities and account for interindividual variability among patients. Indeed, polymorphisms involving genes of the calcium/parathyroid hormone/calcitriol axis have been associated with bone and mineral metabolism abnormalities. This review summarizes studies involving polymorphisms of candidate genes and their effects on the development of complications related to bone and mineral metabolism abnormalities among patients with ESRD.
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Affiliation(s)
- Sehsuvar Erturk
- Department of Nephrology, Ankara University School of Medicine, Ankara, Turkey.
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Saravani R, Qureshi M, Jafari M. Correlation Between Serum Level Parathormone, Alkaline Phosphatase, Calcium and Phosphorus of Patients Hemodialysis in Zahedan. JOURNAL OF MEDICAL SCIENCES 2006. [DOI: 10.3923/jms.2007.154.157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Nakatani S, Mano H, Ryanghyok IM, Shimizu J, Wada M. Excess magnesium inhibits excess calcium-induced matrix-mineralization and production of matrix gla protein (MGP) by ATDC5 cells. Biochem Biophys Res Commun 2006; 348:1157-62. [PMID: 16904632 DOI: 10.1016/j.bbrc.2006.07.180] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2006] [Accepted: 07/28/2006] [Indexed: 11/20/2022]
Abstract
We found that excessive extracellular Ca2+ and/or Mg2+ affected the process of matrix mineralization and glycosaminoglycan (GAG) production by cells of the prechondrogenic cell line, ATDC5. Excess Ca2+ induced both matrix mineralization and GAG production in the cells. On the other hand, excess Mg2+ reduced this Ca2+-mediated rise in both mineralization and GAG production in them. Next we measured the mRNA levels of cartilage-associated genes such as calcium-sensing receptor (CaSR), matrix gla protein (MGP), bone gla protein (BGP), and Runt-related transcription factor 2 (Runx2) in ATDC5 cells. Excess Ca2+ increased the MGP, BGP, and CaSR mRNA levels, and excess Mg2+ reduced the Ca2+-induced increase in the MGP mRNA level in the cells. The changes in the MGP mRNA level paralleled those in the MGP protein level. These data show that Ca2+ and Mg2+ regulated the matrix mineralization positively and negatively, respectively, in ATDC5 cells and suggest that excess Mg2+ might inhibit the excess Ca2+-promoted mineralization mediated by MGP induction in chondrocytes.
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Affiliation(s)
- Sachie Nakatani
- Department of Food Functional Science, Graduate School of Pharmacology, Josai University, Sakado, Saitama 3500295, Japan
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Rašeta N, Kulauzov M, Avram-Šolaja S, Jakovljević B. Bone metabolism in terminal stage of chronic renal insufficiency. SCRIPTA MEDICA 2004. [DOI: 10.5937/scrimed0402067x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
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