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Li X, Lu Y, Zhang L, Song A, Zhang H, Pang B, Liu J, Sun X, Ji H, Huang L, Yang M. Primary and secondary hyperparathyroidism present different expressions of calcium-sensing receptor. BMC Surg 2023; 23:31. [PMID: 36755240 PMCID: PMC9906946 DOI: 10.1186/s12893-023-01928-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 02/01/2023] [Indexed: 02/10/2023] Open
Abstract
BACKGROUND Decreased calcium-sensing receptor (CaSR) has been observed in hyperparathyroidism (HPT) without a known mechanism. The purpose of this study was to evaluate the expression of CaSR in primary (PHPT) and secondary (SHPT) subtypes. METHODS Immunohistochemical (IHC) staining and quantitative real-time PCR (qRT-PCR) assay were used to measure the differences in expression of CaSR protein and gene in PHPT and SHPT human samples, compared to matched controls. RESULTS CaSR protein was differentially downregulated in SHPT and PHPT compared to normal parathyroid tissues (2.42 ± 0.5 vs. 3.2 ± 0.62, P < 0.05; 1.8 ± 0.83 vs. 3.2 ± 0.62, P < 0.05, respectively). Furthermore, SHPT tissues exhibited significantly higher levels of CaSR mRNA (0.29 ± 0.23 vs. 0.01 ± 0.12, P < 0.05) and protein (2.42 ± 0.5 vs. 1.8 ± 0.83, P < 0.05) than those in PHPT tissue samples. CONCLUSION Depressed CaSR expression was a critical pathological hallmark of HPT. We found a differential decline of CaSR, in terms of both mRNA and protein levels, in PHPT and SHPT human samples. We think that CaSR dysregulation occurred at the very beginning of disease onset in PHPT, while a similar pathological scenario appeared at the later stage of SHPT. Future studies should be directed to dissect the mechanistic involvement of CaSR in PHPT and SHPT in order to bring treatment precisions in HPT management.
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Affiliation(s)
- Xin Li
- grid.415954.80000 0004 1771 3349Institute of Clinical Medicine Research, China-Japan Friendship Hospital, Beijing, 100029 China
| | - Yao Lu
- grid.415954.80000 0004 1771 3349Department of General Surgery, China-Japan Friendship Hospital, Beijing, 100029 China
| | - Ling Zhang
- grid.415954.80000 0004 1771 3349Center of Nephrology, China-Japan Friendship Hospital, Beijing, 100029 China
| | - Aiping Song
- grid.415954.80000 0004 1771 3349Department of Pathology, China-Japan Friendship Hospital, Beijing, 100029 China
| | - Honglei Zhang
- grid.415954.80000 0004 1771 3349Department of Pathology, China-Japan Friendship Hospital, Beijing, 100029 China
| | - Bo Pang
- grid.508381.70000 0004 0647 272XState Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, China CDC 155, Changbai Road, Changping, Beijing, 102206 China
| | - Jun Liu
- grid.415954.80000 0004 1771 3349Department of General Surgery, China-Japan Friendship Hospital, Beijing, 100029 China
| | - Xiaoliang Sun
- grid.415954.80000 0004 1771 3349Department of General Surgery, China-Japan Friendship Hospital, Beijing, 100029 China
| | - Haoyang Ji
- grid.415954.80000 0004 1771 3349Department of General Surgery, China-Japan Friendship Hospital, Beijing, 100029 China
| | - Linping Huang
- grid.415954.80000 0004 1771 3349Department of General Surgery, China-Japan Friendship Hospital, Beijing, 100029 China
| | - Meng Yang
- Department of General Surgery, China-Japan Friendship Hospital, Beijing, 100029, China.
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Bover J, Trinidad P, Jara A, Soler-Majoral J, Martín-Malo A, Torres A, Frazão J, Ureña P, Dusso A, Arana C, Graterol F, Romero-González G, Troya M, Samaniego D, D'Marco L, Valdivielso JM, Fernández E, Arenas MD, Torregrosa V, Navarro-González JF, Lloret MJ, Ballarín JA, Bosch RJ, Górriz JL, de Francisco A, Gutiérrez O, Ara J, Felsenfeld A, Canalejo A, Almadén Y. Silver jubilee: 25 years of the first demonstration of the direct effect of phosphate on the parathyroid cell. Nefrologia 2022; 42:645-655. [PMID: 36925324 DOI: 10.1016/j.nefroe.2023.02.008] [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: 12/27/2021] [Accepted: 12/30/2021] [Indexed: 06/18/2023] Open
Abstract
Although phosphorus is an essential element for life, it is not found in nature in its native state but rather combined in the form of inorganic phosphates (PO43-), with tightly regulated plasma levels that are associated with deleterious effects and mortality when these are out of bounds. The growing interest in the accumulation of PO43- in human pathophysiology originated in its attributed role in the pathogenesis of secondary hyperparathyroidism (SHPT) in chronic kidney disease. In this article, we review the mechanisms by which this effect was justified and we commemorate the important contribution of a Spanish group led by Dr. M. Rodríguez, just 25 years ago, when they first demonstrated the direct effect of PO43- on the regulation of the synthesis and secretion of parathyroid hormone by maintaining the structural integrity of the parathyroid glands in their original experimental model. In addition to demonstrating the importance of arachidonic acid (AA) and the phospholipase A2-AA pathway as a mediator of parathyroid gland response, these findings were predecessors of the recent description of the important role of PO43- on the activity of the calcium sensor-receptor, and also fueled various lines of research on the importance of PO43- overload not only for the pathophysiology of SHPT but also in its systemic pathogenic role.
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Affiliation(s)
- Jordi Bover
- Servicio de Nefrología, Hospital Universitario Germans Trias i Pujol, RICORS, Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol (IGTP), Universitat Autònoma de Barcelona, Badalona (Barcelona), Spain.
| | - Pedro Trinidad
- Departamento de Nefrología, HECMN siglo XXI, IMSS, Ciudad de México, México
| | - Aquiles Jara
- Departamento de Nefrología, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Jordi Soler-Majoral
- Servicio de Nefrología, Hospital Universitario Germans Trias i Pujol, RICORS, Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol (IGTP), Universitat Autònoma de Barcelona, Badalona (Barcelona), Spain
| | - Alejandro Martín-Malo
- Unidad de Gestión Clinica Nefrología, Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Hospital Universitario Reina Sofía, Universidad de Córdoba, España. Red Nacional de Investigación en Nefrología (REDinREN), Instituto de Salud Carlos III, Spain
| | - Armando Torres
- Servicio de Nefrología, Hospital Universitario de Canarias, Instituto de Tecnologías Biomédicas, Universidad de La Laguna, Tenerife, Spain
| | - João Frazão
- Department of Nephrology, Centro Hospitalar Universitário São João, Institute for Innovation and Health Research (I3S), Institute of Biomedical Engineering (INEB), Nephrology and Infectious Diseases Research Group, University of Porto, Porto, Portugal
| | - Pablo Ureña
- AURA Nord Saint Ouen Dialysis Service. Saint Ouen, France and Service d'Explorations Fonctionnelles Rénales, Hôpital Necker, Université Paris V, René Descartes, Paris, France
| | - Adriana Dusso
- Division of Endocrinology, Metabolism and Lipid Research, Washington University School of Medicine, St Louis, MO, USA
| | - Carolt Arana
- Departamento de Nefrología y Trasplante Renal, Hospital Clínic, Barcelona, España
| | - Fredzzia Graterol
- Servicio de Nefrología, Hospital Universitario Germans Trias i Pujol, RICORS, Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol (IGTP), Universitat Autònoma de Barcelona, Badalona (Barcelona), Spain
| | - Gregorio Romero-González
- Servicio de Nefrología, Hospital Universitario Germans Trias i Pujol, RICORS, Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol (IGTP), Universitat Autònoma de Barcelona, Badalona (Barcelona), Spain
| | - Maribel Troya
- Servicio de Nefrología, Hospital Universitario Germans Trias i Pujol, RICORS, Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol (IGTP), Universitat Autònoma de Barcelona, Badalona (Barcelona), Spain
| | - Diana Samaniego
- Servicio de Nefrología, Hospital Universitario Germans Trias i Pujol, RICORS, Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol (IGTP), Universitat Autònoma de Barcelona, Badalona (Barcelona), Spain
| | - Luis D'Marco
- CEU Cardenal Herrera University, Valencia, Spain
| | - José Manuel Valdivielso
- Vascular and Renal Translational Research Group, Biomedical Research Institute, IRBLLEIDA, Lleida, España. Red Nacional de Investigación en Nefrología (REDinREN, RETIC), Instituto de Salud Carlos III, Spain
| | - Elvira Fernández
- Vascular and Renal Translational Research Group, Biomedical Research Institute, IRBLLEIDA, Lleida, España. Red Nacional de Investigación en Nefrología (REDinREN, RETIC), Instituto de Salud Carlos III, Spain; Grupo de Investigación Traslacional Vascular y Renal, Fundación Renal Jaume Arnó, Lleida, Spain
| | | | - Vicente Torregrosa
- Departamento de Nefrología y Trasplante Renal, Hospital Clínic, Barcelona, España
| | - Juan F Navarro-González
- Unidad de Investigación y Servicio de Nefrología, Hospital Universitario Nuestra Señora de la Candelaria, Instituto Universitario de Tecnologías Biomédicas, Universidad de la Laguna, Santa Cruz de Tenerife, España. Red Nacional de Investigación en Nefrología (REDinREN, RICORS), Instituto de Salud Carlos III, Spain
| | - María Jesús Lloret
- Servicio de Nefrología, Fundació Puigvert, IIB Sant Pau, Barcelona, Spain
| | - J A Ballarín
- Servicio de Nefrología, Fundació Puigvert, IIB Sant Pau, Barcelona, Spain
| | - Ricardo J Bosch
- Unidad de Fisiología, Departamento de Biología de Sistemas, Facultad de Medicina, Universidad de Alcalá, Alcalá de Henares, Madrid, Spain
| | - José L Górriz
- Servicio de Nefrología, Hospital Clínico Universitario, INCLIVA, Universidad de Valencia, Valencia, Spain
| | | | - Orlando Gutiérrez
- Division of Nephrology, Department of Medicine, Universidad de Alabama en Birmingham, Birmingham USA
| | - Jordi Ara
- Servicio de Nefrología, Hospital Universitario Germans Trias i Pujol, RICORS, Institut d'Investigació en Ciències de la Salut Germans Trias i Pujol (IGTP), Universitat Autònoma de Barcelona, Badalona (Barcelona), Spain
| | - Arnold Felsenfeld
- Department of Medicine, Veterans Affairs Greater Los Angeles Healthcare System and David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Antonio Canalejo
- Departamento de Ciencias Integradas/Centro de Investigación RENSMA, Facultad de Ciencias Experimentales, Universidad de Huelva. Huelva, Spain
| | - Yolanda Almadén
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Hospital Universitario Reina Sofía, Universidad de Córdoba, Córdoba, Spain
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The American Association of Endocrine Surgeons Guidelines for the Definitive Surgical Management of Secondary and Tertiary Renal Hyperparathyroidism. Ann Surg 2022; 276:e141-e176. [PMID: 35848728 DOI: 10.1097/sla.0000000000005522] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To develop evidence-based recommendations for safe, effective, and appropriate treatment of secondary (SHPT) and tertiary (THPT) renal hyperparathyroidism. BACKGROUND Hyperparathyroidism is common among patients with chronic kidney disease, end-stage kidney disease, and kidney transplant. The surgical management of SHPT and THPT is nuanced and requires a multidisciplinary approach. There are currently no clinical practice guidelines that address the surgical treatment of SHPT and THPT. METHODS Medical literature was reviewed from January 1, 1985 to present January 1, 2021 by a panel of 10 experts in SHPT and THPT. Recommendations using the best available evidence was constructed. The American College of Physicians grading system was used to determine levels of evidence. Recommendations were discussed to consensus. The American Association of Endocrine Surgeons membership reviewed and commented on preliminary drafts of the content. RESULTS These clinical guidelines present the epidemiology and pathophysiology of SHPT and THPT and provide recommendations for work-up and management of SHPT and THPT for all involved clinicians. It outlines the preoperative, intraoperative, and postoperative management of SHPT and THPT, as well as related definitions, operative techniques, morbidity, and outcomes. Specific topics include Pathogenesis and Epidemiology, Initial Evaluation, Imaging, Preoperative and Perioperative Care, Surgical Planning and Parathyroidectomy, Adjuncts and Approaches, Outcomes, and Reoperation. CONCLUSIONS Evidence-based guidelines were created to assist clinicians in the optimal management of secondary and tertiary renal hyperparathyroidism.
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Bodas de plata: 25 años de la primera demostración del efecto directo del fósforo en la célula paratiroidea. Nefrologia 2022. [DOI: 10.1016/j.nefro.2021.12.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Dobenecker B, Kienzle E, Siedler S. The Source Matters-Effects of High Phosphate Intake from Eight Different Sources in Dogs. Animals (Basel) 2021; 11:ani11123456. [PMID: 34944233 PMCID: PMC8698167 DOI: 10.3390/ani11123456] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 12/01/2021] [Accepted: 12/02/2021] [Indexed: 01/21/2023] Open
Abstract
Elevated serum phosphate concentrations are an established risk factor for cardiovascular disease and mortality in chronic kidney disease in various species. Independent associations of other parameters of phosphorus metabolism, such as phosphorus intake from different sources and serum concentrations of phosphorus, as well as parameters involved in the regulation, such as parathyroid hormone (PTH) or markers of bone turnover, have been studied in less detail. Therefore, the serum kinetics of phosphate, PTH, and the bone resorption marker bone-specific alkaline phosphatase (BAP) were investigated after 18 days of feeding a control diet and diets supplemented with eight different organic and inorganic phosphate sources aiming at 1.8% phosphorus per dry matter and calcium to phosphorus ratio between 1.3 and 1.7 to 1. Eight healthy beagle dogs (f/m, 2-4 years, 12.9 ± 1.4 kg body weight) were available for the trial. Highly significant differences in the serum kinetics of phosphorus, PTH, and BAP with the highest postprandial levels after feeding highly water-soluble sodium and potassium phosphates were found. We conclude that the use of certain inorganic phosphates in pet food is potentially harmful and should be restricted.
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Bover J, Arana C, Ureña P, Torres A, Martín-Malo A, Fayos L, Coll V, Lloret MJ, Ochoa J, Almadén Y, Guirado L, Rodríguez M. Hyporesponsiveness or resistance to the action of parathyroid hormone in chronic kidney disease. Nefrologia 2021; 41:514-528. [PMID: 36165134 DOI: 10.1016/j.nefroe.2021.11.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 12/20/2020] [Indexed: 06/16/2023] Open
Abstract
Secondary hyperparathyroidism (SHPT) is an integral component of the chronic kidney disease-mineral and bone disorder (CKD-MBD). Many factors have been associated with the development and progression of SHPT but the presence of skeletal or calcemic resistance to the action of PTH in CKD has often gone unnoticed. The term hyporesponsiveness to PTH is currently preferred and, in this chapter, we will not only review the scientific timeline but also some of the molecular mechanisms behind. Moreover, the presence of resistance to the biological action of PTH is not unique in CKD since resistance to other hormones has also been described ("uremia as a receptor disease"). This hyporesponsiveness carries out important clinical implications since it explains, at least partially, not only the progressive nature of the pathogenesis of CKD-related PTH hypersecretion and parathyroid hyperplasia but also the increasing prevalence of adynamic bone disease in the CKD population. Therefore, we underline the importance of PTH control in all CKD stages, but not aiming to completely normalize PTH levels since a certain degree of SHPT may represent an adaptive clinical response. Future studies at the molecular level, i.e. on uremia or the recent description of the calcium-sensing receptor as a phosphate sensor, may become of great value beyond their significance to explain just the hyporesponsiveness to PTH in CKD.
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Affiliation(s)
- Jordi Bover
- Servicio de Nefrología, Fundació Puigvert, IIB Sant Pau, REDinREN, Barcelona, Spain.
| | - Carolt Arana
- Servicio de Nefrología, Fundació Puigvert, IIB Sant Pau, REDinREN, Barcelona, Spain
| | - Pablo Ureña
- AURA Nord Saint Ouen y Departamento de Fisiología Renal, Hospital Necker, Universidad de París Descartes, Paris, France
| | - Armando Torres
- Servicio de Nefrología, Hospital Universitario de Canarias, REDinREN, Universidad de La Laguna, Tenerife, Spain
| | - Alejandro Martín-Malo
- Unidad de Gestión Clinica Nefrología, Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Hospital Universitario Reina Sofía, Universidad de Córdoba, Córdoba, Spain; Red Nacional de Investigación en Nefrología (REDinREN), Instituto de Salud Carlos III, Madrid, Spain
| | - Leonor Fayos
- Servicio de Nefrología, Fundació Puigvert, IIB Sant Pau, REDinREN, Barcelona, Spain
| | - Verónica Coll
- Servicio de Nefrología, Fundació Puigvert, IIB Sant Pau, REDinREN, Barcelona, Spain
| | - María Jesús Lloret
- Servicio de Nefrología, Fundació Puigvert, IIB Sant Pau, REDinREN, Barcelona, Spain
| | - Jackson Ochoa
- Servicio de Nefrología, Fundació Puigvert, IIB Sant Pau, REDinREN, Barcelona, Spain
| | - Yolanda Almadén
- Unidad de Gestión Clínica Medicina Interna, Lipid and Atherosclerosis Unit, Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Hospital Universitario Reina Sofía, Universidad de Córdoba, Córdoba, Spain; CIBER Fisiopatología Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid, Spain
| | - Lluis Guirado
- Servicio de Nefrología, Fundació Puigvert, IIB Sant Pau, REDinREN, Barcelona, Spain
| | - Mariano Rodríguez
- Unidad de Gestión Clinica Nefrología, Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Hospital Universitario Reina Sofía, Universidad de Córdoba, Córdoba, Spain; Red Nacional de Investigación en Nefrología (REDinREN), Instituto de Salud Carlos III, Madrid, Spain
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7
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Bover J, Arana C, Ureña P, Torres A, Martín-Malo A, Fayos L, Coll V, Lloret MJ, Ochoa J, Almadén Y, Guirado L, Rodríguez M. Hyporesponsiveness or resistance to the action of parathyroid hormone in chronic kidney disease. Nefrologia 2021. [PMID: 33985858 DOI: 10.1016/j.nefro.2020.12.019] [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] [Indexed: 12/12/2022] Open
Abstract
Secondary hyperparathyroidism (SHPT) is an integral component of the chronic kidney disease-mineral and bone disorder (CKD-MBD). Many factors have been associated with the development and progression of SHPT but the presence of skeletal or calcemic resistance to the action of PTH in CKD has often gone unnoticed. The term hyporesponsiveness to PTH is currently preferred and, in this chapter, we will not only review the scientific timeline but also some of the molecular mechanisms behind. Moreover, the presence of resistance to the biological action of PTH is not unique in CKD since resistance to other hormones has also been described ("uremia as a receptor disease"). This hyporesponsiveness carries out important clinical implications since it explains, at least partially, not only the progressive nature of the pathogenesis of CKD-related PTH hypersecretion and parathyroid hyperplasia but also the increasing prevalence of adynamic bone disease in the CKD population. Therefore, we underline the importance of PTH control in all CKD stages, but not aiming to completely normalize PTH levels since a certain degree of SHPT may represent an adaptive clinical response. Future studies at the molecular level, i.e. on uremia, or the recent description of the calcium-sensing receptor as a phosphate sensor, may become of great value beyond their significance to explain just the hyporesponsiveness to PTH in CKD.
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Affiliation(s)
- Jordi Bover
- Servicio de Nefrología, Fundació Puigvert, IIB Sant Pau, REDinREN, Barcelona, España.
| | - Carolt Arana
- Servicio de Nefrología, Fundació Puigvert, IIB Sant Pau, REDinREN, Barcelona, España
| | - Pablo Ureña
- AURA Nord Saint Ouen y Departamento de Fisiología Renal, Hospital Necker, Universidad de París Descartes, París, Francia
| | - Armando Torres
- Servicio de Nefrología, Hospital Universitario de Canarias, REDinREN, Universidad de La Laguna, Tenerife, España
| | - Alejandro Martín-Malo
- Unidad de Gestión Clínica Nefrología, Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Hospital Universitario Reina Sofía, Universidad de Córdoba, Córdoba, España; Red Nacional de Investigación en Nefrología (REDinREN), Instituto de Salud Carlos III, Madrid, España
| | - Leonor Fayos
- Servicio de Nefrología, Fundació Puigvert, IIB Sant Pau, REDinREN, Barcelona, España
| | - Verónica Coll
- Servicio de Nefrología, Fundació Puigvert, IIB Sant Pau, REDinREN, Barcelona, España
| | - María Jesús Lloret
- Servicio de Nefrología, Fundació Puigvert, IIB Sant Pau, REDinREN, Barcelona, España
| | - Jackson Ochoa
- Servicio de Nefrología, Fundació Puigvert, IIB Sant Pau, REDinREN, Barcelona, España
| | - Yolanda Almadén
- Unidad de Gestión Clínica Medicina Interna, Lipid and Atherosclerosis Unit, Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Hospital Universitario Reina Sofía, Universidad de Córdoba, Córdoba, España; CIBER Fisiopatología Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III, Madrid, España
| | - Lluis Guirado
- Servicio de Nefrología, Fundació Puigvert, IIB Sant Pau, REDinREN, Barcelona, España
| | - Mariano Rodríguez
- Unidad de Gestión Clínica Nefrología, Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Hospital Universitario Reina Sofía, Universidad de Córdoba, Córdoba, España; Red Nacional de Investigación en Nefrología (REDinREN), Instituto de Salud Carlos III, Madrid, España
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8
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Svajger BA, Pruss CM, Laverty KJ, Zelt JGE, Jones G, Kaufmann M, Petkovich M, Holden RM, Adams MA. PTH suppression by calcitriol does not predict off-target actions in experimental CKD. Pharmacol Res Perspect 2021; 8:e00605. [PMID: 32519465 PMCID: PMC7283992 DOI: 10.1002/prp2.605] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 05/12/2020] [Indexed: 12/28/2022] Open
Abstract
Vitamin D receptor agonist (VDRA) therapy for PTH suppression is a mainstay for patients with severe CKD. Calcitriol (1,25‐(OH)2D3) is a former first‐line VDRA in CKD treatment. However, a consequence of its use in CKD is accelerated vascular calcification (VC). An experimental CKD model was used to determine whether altering the calcitriol delivery profile to obtain different PTH suppression levels could improve vascular health outcomes. High adenine diet (0.25%) was used to generate experimental CKD in rats. CKD rats were treated using different calcitriol dosing strategies: (a) 20 ng/kg SD (n = 8), (b) 80 ng/kg SD (n = 8), (c) 5 ng/kg QID (n = 9), or (d) 20 ng/kg QID (n = 9). Multiple targets of calcitriol were assessed which include arterial calcium and phosphate as well as circulating calcium, phosphate, PTH, FGF‐23, VWF, and vitamin D metabolome. PTH suppression occurred dose‐dependently after 1‐week calcitriol treatment (P < .01), but the suppressive effect was lost over time. Both VC and circulating FGF‐23 increased > 10× in all calcitriol‐treated rats (P < .05 and P < .001, respectively); similarly, circulating VWF increased at all time points (P < .05). Ad‐hoc analysis of CKD morbidities in treated rats indicated no differences in negative outcomes based on PTH suppression level (minimal‐, target‐, and over‐). Comparing different calcitriol dosing strategies revealed the following: (a) despite initial calcitriol‐influenced PTH suppression across all treatments, the ability to continually suppress PTH was markedly reduced by study conclusion and (b) PTH suppression level is not an adequate proxy for improvements in overall CKD morbidity. These findings show (a) a more holistic approach to evaluate CKD treatment efficacy aside from PTH suppression is needed and (b) that other VDRA therapies should be examined in CKD treatment.
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Affiliation(s)
- Bruno A Svajger
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
| | - Cynthia M Pruss
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
| | - Kimberly J Laverty
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
| | - Jason G E Zelt
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada.,Molecular Function and Imaging Program, The National Cardiac PET Centre, and the Advanced Heart Disease Program, Division of Cardiology, Department of Medicine, University of Ottawa Heart Institute and University of Ottawa, Ottawa, Ontario, Canada
| | - Glenville Jones
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
| | - Martin Kaufmann
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
| | - Martin Petkovich
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
| | - Rachel M Holden
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada.,Department of Medicine, Queen's University, Kingston, Ontario, Canada
| | - Michael A Adams
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
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Oster M, Reyer H, Gerlinger C, Trakooljul N, Siengdee P, Keiler J, Ponsuksili S, Wolf P, Wimmers K. mRNA Profiles of Porcine Parathyroid Glands Following Variable Phosphorus Supplies throughout Fetal and Postnatal Life. Biomedicines 2021; 9:biomedicines9050454. [PMID: 33922173 PMCID: PMC8146947 DOI: 10.3390/biomedicines9050454] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 04/16/2021] [Accepted: 04/18/2021] [Indexed: 11/16/2022] Open
Abstract
Knowledge of gene expression profiles reflecting functional features and specific responsiveness of parathyroid glands (PTGs) contributes to understanding mineral homeostasis and parathyroid function in healthy and diseased conditions. The study aims to reveal effector molecules driving the maintenance of phosphorus (P) homeostasis and parathyroid hormone (PTH) responsiveness to variable P supply throughout fetal and postnatal life. In this study, a long-term dietary intervention was performed by keeping pig offspring on distinct mineral P levels throughout fetal and postnatal life. Respective adaptation processes of P homeostasis were assessed in mRNA profiles of PTGs and serum minerals. RNA sequencing data and resulting molecular pathways of PTGs showed that the PTH abundance is very strictly controlled via e.g., PIN1, CaSR, MAfB, PLC and PKA signaling to regulate PTH expression, stability, and secretion. Additionally, the observed dietary effects on collagen expression indicate shifts in the ratio between connective tissue and parenchyma, thereby affecting cell-cell contacts as another line of PTH regulation. Taken together, the mRNA profiles of porcine PTGs reflect physiological responses in-vivo following variable dietary P supplies during fetal and postnatal life. The results serve to evaluate a long-term nutrition strategy with implications for improving the mineral balance in individuals with pathological disorders.
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Affiliation(s)
- Michael Oster
- Institute of Genome Biology, Leibniz Institute for Farm Animal Biology (FBN), 18196 Dummerstorf, Germany; (M.O.); (H.R.); (C.G.); (N.T.); (P.S.); (S.P.)
| | - Henry Reyer
- Institute of Genome Biology, Leibniz Institute for Farm Animal Biology (FBN), 18196 Dummerstorf, Germany; (M.O.); (H.R.); (C.G.); (N.T.); (P.S.); (S.P.)
| | - Christian Gerlinger
- Institute of Genome Biology, Leibniz Institute for Farm Animal Biology (FBN), 18196 Dummerstorf, Germany; (M.O.); (H.R.); (C.G.); (N.T.); (P.S.); (S.P.)
| | - Nares Trakooljul
- Institute of Genome Biology, Leibniz Institute for Farm Animal Biology (FBN), 18196 Dummerstorf, Germany; (M.O.); (H.R.); (C.G.); (N.T.); (P.S.); (S.P.)
| | - Puntita Siengdee
- Institute of Genome Biology, Leibniz Institute for Farm Animal Biology (FBN), 18196 Dummerstorf, Germany; (M.O.); (H.R.); (C.G.); (N.T.); (P.S.); (S.P.)
| | - Jonas Keiler
- Department of Anatomy, Rostock University Medical Center, 18057 Rostock, Germany;
| | - Siriluck Ponsuksili
- Institute of Genome Biology, Leibniz Institute for Farm Animal Biology (FBN), 18196 Dummerstorf, Germany; (M.O.); (H.R.); (C.G.); (N.T.); (P.S.); (S.P.)
| | - Petra Wolf
- Faculty of Agricultural and Environmental Sciences, University Rostock, 18059 Rostock, Germany;
| | - Klaus Wimmers
- Institute of Genome Biology, Leibniz Institute for Farm Animal Biology (FBN), 18196 Dummerstorf, Germany; (M.O.); (H.R.); (C.G.); (N.T.); (P.S.); (S.P.)
- Faculty of Agricultural and Environmental Sciences, University Rostock, 18059 Rostock, Germany;
- Correspondence: ; Tel.: +49-382-086-8600
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10
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Schappacher-Tilp G, Cherif A, Fuertinger DH, Bushinsky D, Kotanko P. A mathematical model of parathyroid gland biology. Physiol Rep 2020; 7:e14045. [PMID: 30927339 PMCID: PMC6440916 DOI: 10.14814/phy2.14045] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 03/07/2019] [Accepted: 03/08/2019] [Indexed: 11/24/2022] Open
Abstract
Altered parathyroid gland biology in patients with chronic kidney disease (CKD) is a major contributor to chronic kidney disease-mineral bone disorder (CKD-MBD). This disorder is associated with an increased risk of bone disorders, vascular calcification, and cardiovascular events. Parathyroid hormone (PTH) secretion is primarily regulated by the ionized calcium concentration as well as the phosphate concentration in the extracellular fluid and vitamin D. The metabolic disturbances in patients with CKD lead to alterations in the parathyroid gland biology. A hallmark of CKD is secondary hyperparathyroidism, characterized by an increased production and release of PTH, reduced expression of calcium-sensing and vitamin D receptors on the surface of parathyroid cells, and hyperplasia and hypertrophy of these cells. These alterations happen on different timescales and influence each other, thereby triggering a cascade of negative and positive feedback loops in a highly complex manner. Due to this complexity, mathematical models are a useful tool to break down the patterns of the multidimensional cascade of processes enabling the detailed study of subsystems. Here, we introduce a comprehensive mathematical model that includes the major adaptive mechanisms governing the production, secretion, and degradation of PTH in patients with CKD on hemodialysis. Combined with models for medications targeting the parathyroid gland, it provides a ready-to-use tool to explore treatment strategies. While the model is of particular interest for use in hemodialysis patients with secondary hyperparathyroidism, it has the potential to be applicable to other clinical scenarios such as primary hyperparathyroidism or hypo- and hypercalcemia.
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Affiliation(s)
| | - Alhaji Cherif
- Renal Research Institute, New York City, New York.,School of Mathematical and Statistical Sciences, Arizona State University, Tempe, Arizona
| | - Doris H Fuertinger
- Global Research and Development, Fresenius Medical Care Germany, Bad Homburg, Germany
| | - David Bushinsky
- Division of Nephrology, Department of Medicine, University of Rochester School of Medicine, Rochester, New York
| | - Peter Kotanko
- Renal Research Institute, New York City, New York.,Icahn School of Medicine at Mount Sinai, New York City, New York
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11
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Rodríguez-Ortiz ME, Pendón-Ruiz de Mier MV, Rodríguez M. Parathyroidectomy in dialysis patients: Indications, methods, and consequences. Semin Dial 2019; 32:444-451. [PMID: 30656752 DOI: 10.1111/sdi.12772] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Secondary hyperparathyroidism, characterized by increased PTH synthesis and secretion, is often seen in advanced stages of chronic kidney disease. Excessive proliferation of parathyroid cells leads to the development of diffuse hyperplasia that subsequently progresses to nodular histology. Refractory hyperparathyroidism occurs when parathyroid glands fail to respond to medical therapy. Parathyroidectomy (PTX), surgical resection of parathyroid glands, is usually performed in cases of persistent serum levels of PTH above 1000 pg/mL associated with hypercalcemia or when hyperparathyroidism is refractory to conservative therapy. Parathyroidectomy can be carried out using different procedures: subtotal PTX or total PTX with or without parathyroid autotransplantation. Parathyroid surgery may have undesirable consequences due to PTH oversuppression, such as the development of adynamic bone disease; hungry bone syndrome is quite common after this surgery. However, PTX improves survival and parameters of mineral metabolism. Parathyroidectomy needs to be considered in those patients with severe hyperparathyroidism with a poor response to pharmacological treatment and with distinct undesirable effects of PTH on bone and mineral metabolism parameters.
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Affiliation(s)
- María E Rodríguez-Ortiz
- Maimónides Institute for Biomedical Research (IMIBIC), Córdoba, Spain.,Reina Sofía University Hospital, Córdoba, Spain.,University of Córdoba, Córdoba, Spain.,Spanish Renal Research Network (REDinREN), Institute of Health Carlos III, Madrid, Spain
| | - María V Pendón-Ruiz de Mier
- Maimónides Institute for Biomedical Research (IMIBIC), Córdoba, Spain.,Reina Sofía University Hospital, Córdoba, Spain.,University of Córdoba, Córdoba, Spain.,Spanish Renal Research Network (REDinREN), Institute of Health Carlos III, Madrid, Spain
| | - Mariano Rodríguez
- Maimónides Institute for Biomedical Research (IMIBIC), Córdoba, Spain.,University of Córdoba, Córdoba, Spain.,Spanish Renal Research Network (REDinREN), Institute of Health Carlos III, Madrid, Spain.,Nephrology Service, University Hospital Reina Sofía, Córdoba, Spain
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12
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Mizobuchi M, Ogata H, Koiwa F. Secondary Hyperparathyroidism: Pathogenesis and Latest Treatment. Ther Apher Dial 2018; 23:309-318. [PMID: 30411503 DOI: 10.1111/1744-9987.12772] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 10/23/2018] [Accepted: 11/02/2018] [Indexed: 01/02/2023]
Abstract
The classic pathogenesis of secondary hyperparathyroidism (SHPT) began with the trade-off hypothesis based on parathyroid hormone hypersecretion brought about by renal failure resulting from a physiological response to correct metabolic disorder of calcium, phosphorus, and vitamin D. In dialysis patients with failed renal function, physiological mineral balance control by parathyroid hormone through the kidney fails and hyperparathyroidism progresses. In this process, many significant genetic findings have been established. Abnormalities of Ca-sensing receptor and vitamin D receptor are associated with the pathogenesis of SHPT, and fibroblast growth factor 23 has also been shown to be involved in the pathogenesis. Vitamin D receptor activators (VDRAs) are widely used for treatment of SHPT. However, VDRAs have calcemic and phosphatemic effects that limit their use to a subset of patients, and calcimimetics have been developed as alternative drugs for SHPT. Hyperphosphatemia also affects progression of SHPT, and control of hyperphosphatemia is, therefore, thought to be fundamental for control of SHPT. Currently, a combination of a VDRA and a calcimimetic is recognized as the optimal strategy for SHPT, and for other outcomes such as reduced cardiovascular disease and improved survival. The latest findings on the pathogenesis and treatment of SHPT are summarized in this review.
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Affiliation(s)
- Masahide Mizobuchi
- Division of Nephrology, Department of Medicine, Showa University School of Medicine, Tokyo, Japan
| | - Hiroaki Ogata
- Department of Medicine, Showa University Northern Yokohama Hospital, Yokohama, Japan
| | - Fumihiko Koiwa
- Division of Nephrology, Department of Medicine, Showa University Fujigaoka Hospital, Yokohama, Japan
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13
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Lu CL, Yeih DF, Hou YC, Jow GM, Li ZY, Liu WC, Zheng CM, Lin YF, Shyu JF, Chen R, Huang CY, Lu KC. The Emerging Role of Nutritional Vitamin D in Secondary Hyperparathyroidism in CKD. Nutrients 2018; 10:nu10121890. [PMID: 30513912 PMCID: PMC6316278 DOI: 10.3390/nu10121890] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 11/22/2018] [Accepted: 11/23/2018] [Indexed: 12/18/2022] Open
Abstract
In chronic kidney disease (CKD), hyperphosphatemia induces fibroblast growth factor-23 (FGF-23) expression that disturbs renal 1,25-dihydroxy vitamin D (1,25D) synthesis; thereby increasing parathyroid hormone (PTH) production. FGF-23 acts on the parathyroid gland (PTG) to increase 1α-hydroxylase activity and results in increase intra-gland 1,25D production that attenuates PTH secretion efficiently if sufficient 25D are available. Interesting, calcimimetics can further increase PTG 1α-hydroxylase activity that emphasizes the demand for nutritional vitamin D (NVD) under high PTH status. In addition, the changes in hydroxylase enzyme activity highlight the greater parathyroid 25-hydroxyvitmain D (25D) requirement in secondary hyperparathyroidism (SHPT); the higher proportion of oxyphil cells as hyperplastic parathyroid progression; lower cytosolic vitamin D binding protein (DBP) content in the oxyphil cell; and calcitriol promote vitamin D degradation are all possible reasons supports nutritional vitamin D (NVD; e.g., Cholecalciferol) supplement is crucial in SHPT. Clinically, NVD can effectively restore serum 25D concentration and prevent the further increase in PTH level. Therefore, NVD might have the benefit of alleviating the development of SHPT in early CKD and further lowering PTH in moderate to severe SHPT in dialysis patients.
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Affiliation(s)
- Chien-Lin Lu
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan.
- Division of Nephrology, Department of Medicine, Fu Jen Catholic University Hospital, School of Medicine, Fu Jen Catholic University, New Taipei City 242, Taiwan.
| | - Dong-Feng Yeih
- Division of Cardiology, Department of Medicine, Fu Jen Catholic University Hospital, School of Medicine, Fu Jen Catholic University, New Taipei City 242, Taiwan.
| | - Yi-Chou Hou
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan.
- Division of Nephrology, Department of Medicine, Cardinal-Tien Hospital, School of Medicine, Fu Jen Catholic University, New Taipei City 23155, Taiwan.
| | - Guey-Mei Jow
- Division of Nephrology, Department of Medicine, Fu Jen Catholic University Hospital, School of Medicine, Fu Jen Catholic University, New Taipei City 242, Taiwan.
| | - Zong-Yu Li
- Division of Nephrology, Department of Medicine, Fu Jen Catholic University Hospital, School of Medicine, Fu Jen Catholic University, New Taipei City 242, Taiwan.
| | - Wen-Chih Liu
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan.
- Division of Nephrology, Department of Internal Medicine, Tungs' Taichung MetroHarbor Hospital, Taichung City 433, Taiwan.
| | - Cai-Mei Zheng
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan.
- Division of Nephrology, Department of Internal Medicine, Shuang Ho Hospital, New Taipei City 235, Taiwan.
- Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11103, Taiwan.
| | - Yuh-Feng Lin
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan.
- Division of Nephrology, Department of Internal Medicine, Shuang Ho Hospital, New Taipei City 235, Taiwan.
- Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11103, Taiwan.
| | - Jia-Fwu Shyu
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan.
- Department of Biology and Anatomy, National Defense Medical Center, Taipei 114, Taiwan.
| | - Remy Chen
- Kidney Dialysis Center, Kamifukuoka General Hospital, Saitama 356, Japan.
| | - Chung-Yu Huang
- Department of Medicine, Show-Chwan Memorial Hospital, Changhua 50008, Taiwan.
| | - Kuo-Cheng Lu
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan.
- Division of Nephrology, Department of Medicine, Fu Jen Catholic University Hospital, School of Medicine, Fu Jen Catholic University, New Taipei City 242, Taiwan.
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14
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Hannan FM, Kallay E, Chang W, Brandi ML, Thakker RV. The calcium-sensing receptor in physiology and in calcitropic and noncalcitropic diseases. Nat Rev Endocrinol 2018; 15:33-51. [PMID: 30443043 PMCID: PMC6535143 DOI: 10.1038/s41574-018-0115-0] [Citation(s) in RCA: 191] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The Ca2+-sensing receptor (CaSR) is a dimeric family C G protein-coupled receptor that is expressed in calcitropic tissues such as the parathyroid glands and the kidneys and signals via G proteins and β-arrestin. The CaSR has a pivotal role in bone and mineral metabolism, as it regulates parathyroid hormone secretion, urinary Ca2+ excretion, skeletal development and lactation. The importance of the CaSR for these calcitropic processes is highlighted by loss-of-function and gain-of-function CaSR mutations that cause familial hypocalciuric hypercalcaemia and autosomal dominant hypocalcaemia, respectively, and also by the fact that alterations in parathyroid CaSR expression contribute to the pathogenesis of primary and secondary hyperparathyroidism. Moreover, the CaSR is an established therapeutic target for hyperparathyroid disorders. The CaSR is also expressed in organs not involved in Ca2+ homeostasis: it has noncalcitropic roles in lung and neuronal development, vascular tone, gastrointestinal nutrient sensing, wound healing and secretion of insulin and enteroendocrine hormones. Furthermore, the abnormal expression or function of the CaSR is implicated in cardiovascular and neurological diseases, as well as in asthma, and the CaSR is reported to protect against colorectal cancer and neuroblastoma but increase the malignant potential of prostate and breast cancers.
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Affiliation(s)
- Fadil M Hannan
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Enikö Kallay
- Department of Pathophysiology and Allergy Research, Medical University of Vienna, Vienna, Austria
| | - Wenhan Chang
- Endocrine Research Unit, Veterans Affairs Medical Center, University of California, San Francisco, San Francisco, CA, USA
| | - Maria Luisa Brandi
- Metabolic Bone Diseases Unit, Department of Surgery and Translational Medicine, University of Florence, Florence, Italy.
| | - Rajesh V Thakker
- Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, UK.
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15
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Bover J, Ureña P, Aguilar A, Mazzaferro S, Benito S, López-Báez V, Ramos A, daSilva I, Cozzolino M. Alkaline Phosphatases in the Complex Chronic Kidney Disease-Mineral and Bone Disorders. Calcif Tissue Int 2018; 103:111-124. [PMID: 29445837 DOI: 10.1007/s00223-018-0399-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 01/29/2018] [Indexed: 12/16/2022]
Abstract
Alkaline phosphatases (APs) remove the phosphate (dephosphorylation) needed in multiple metabolic processes (from many molecules such as proteins, nucleotides, or pyrophosphate). Therefore, APs are important for bone mineralization but paradoxically they can also be deleterious for other processes, such as vascular calcification and the increasingly known cross-talk between bone and vessels. A proper balance between beneficial and harmful activities is further complicated in the context of chronic kidney disease (CKD). In this narrative review, we will briefly update the complexity of the enzyme, including its different isoforms such as the bone-specific alkaline phosphatase or the most recently discovered B1x. We will also analyze the correlations and potential discrepancies with parathyroid hormone and bone turnover and, most importantly, the valuable recent associations of AP's with cardiovascular disease and/or vascular calcification, and survival. Finally, a basic knowledge of the synthetic and degradation pathways of APs promises to open new therapeutic strategies for the treatment of the CKD-Mineral and Bone Disorder (CKD-MBD) in the near future, as well as for other processes such as sepsis, acute kidney injury, inflammation, endothelial dysfunction, metabolic syndrome or, in diabetes, cardiovascular complications. However, no studies have been done using APs as a primary therapeutic target for clinical outcomes, and therefore, AP's levels cannot yet be used alone as an isolated primary target in the treatment of CKD-MBD. Nonetheless, its diagnostic and prognostic potential should be underlined.
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Affiliation(s)
- Jordi Bover
- Department of Nephrology, Fundació Puigvert, IIB Sant Pau, RedinRen, C. Cartagena, Catalonia, 340-350, Barcelona, Spain.
| | - Pablo Ureña
- Department of Nephrology and Dialysis, Clinique du Landy and Department of Renal Physiology, Necker Hospital, University of Paris Descartes, Paris, France
| | - Armando Aguilar
- Department of Nephrology, Fundació Puigvert, IIB Sant Pau, RedinRen, C. Cartagena, Catalonia, 340-350, Barcelona, Spain
| | - Sandro Mazzaferro
- Department of Cardiovascular, Respiratory, Nephrologic and Geriatric Sciences, Sapienza University of Rome, Rome, Italy
| | - Silvia Benito
- Department of Nephrology, Fundació Puigvert, IIB Sant Pau, RedinRen, C. Cartagena, Catalonia, 340-350, Barcelona, Spain
| | - Víctor López-Báez
- Department of Nephrology, Fundació Puigvert, IIB Sant Pau, RedinRen, C. Cartagena, Catalonia, 340-350, Barcelona, Spain
| | - Alejandra Ramos
- Department of Nephrology, Fundació Puigvert, IIB Sant Pau, RedinRen, C. Cartagena, Catalonia, 340-350, Barcelona, Spain
| | - Iara daSilva
- Department of Nephrology, Fundació Puigvert, IIB Sant Pau, RedinRen, C. Cartagena, Catalonia, 340-350, Barcelona, Spain
| | - Mario Cozzolino
- Laboratory of Experimental Nephrology, Renal Division,San Paolo Hospital, DiSS University of Milan, Milan, Italy
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16
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Portillo MR, Rodríguez-Ortiz ME. Secondary Hyperparthyroidism: Pathogenesis, Diagnosis, Preventive and Therapeutic Strategies. Rev Endocr Metab Disord 2017; 18:79-95. [PMID: 28378123 DOI: 10.1007/s11154-017-9421-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Uremic secondary hyperparathyroidism is a multifactorial and complex disease often present in advanced stages of chronic kidney disease. The accumulation of phosphate, the increased FGF23 levels, the reduction in active vitamin D production, and the tendency to hypocalcemia are persistent stimuli for the development and progression of parathyroid hyperplasia with increased secretion of PTH. Parathyroid proliferation may become nodular mainly in cases of advanced hyperparathyroidism. The alterations in the regulation of mineral metabolism, the development of bone disease and extraosseous calcifications are essential components of chronic kidney disease-mineral and bone disorder and have been associated with negative outcomes. The management of hyperparathyroidism includes the correction of vitamin D deficiency and control of serum phosphorus and PTH without inducing hypercalcemia. An update of the leading therapeutic tools available for the prevention and clinical management of secondary hyperparathyroidism, its diagnosis, and the main mechanisms and factors involved in the pathogenesis of the disease will be described in this review.
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Affiliation(s)
- Mariano Rodríguez Portillo
- Nephrology Service, Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Reina Sofía University Hospital/University of Córdoba, Avda. Menéndez Pidal, S/N, 14004, Córdoba, Spain.
- REDinREN, Madrid, Spain.
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17
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Uchiyama T, Tatsumi N, Kamejima S, Waku T, Ohkido I, Yokoyama K, Yokoo T, Okabe M. Hypermethylation of the CaSR and VDR genes in the parathyroid glands in chronic kidney disease rats with high-phosphate diet. Hum Cell 2016; 29:155-61. [PMID: 27589858 DOI: 10.1007/s13577-016-0143-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 07/27/2016] [Indexed: 01/04/2023]
Abstract
Chronic kidney disease (CKD) disrupts mineral homeostasis and its representative pathosis is defined as secondary hyperparathyroidism (SHPT). SHPT occurs during the early course of progressive renal insufficiency, and is associated with mortality and cardiovascular events. SHPT results in reduction of calcium-sensing receptor (CaSR) and vitamin D receptor (VDR) in the parathyroid glands during CKD. However, the precise mechanism of CaSR and VDR reduction is largely unknown. CKD was induced through two-step 5/6 nephrectomy, and then CKD rats and sham-operated rats were maintained for 8 weeks on diets containing 0.7 % phosphorus (normal phosphate) or 1.2 % phosphorus (high phosphate). In gene expression analysis, TaqMan probes were used for quantitative real-time polymerase chain reaction. Finally, CaSR and VDR protein expressions were analyzed using immunohistochemistry. DNA methylation analysis was performed using a restriction digestion and quantitative PCR. CaSR and VDR mRNA were reduced only in CKD rats fed the high-phosphorus diets (CKD HP), then CaSR and VDR immunohistochemical expressions were compatible with gene expression assay. SHPT was then confirmed only in CKD HP rats. Furthermore, sole CKD HP rats showed the hypermethylation in CaSR and VDR genes; however, the percentage methylation of both genes was low. Although CaSR and VDR hypermethylation was demonstrated in PTGs of CKD HP rats, the extent of hypermethylation was insufficient to support the relevance between hypermethylation and down-regulation of gene expression because of the low percentage of methylation. Consequently, our data suggest that mechanisms, other than DNA hypermethylation, were responsible for the reduction in mRNA and protein levels of CaSR and VDR in PTGs of CKD HP rats.
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Affiliation(s)
- Taketo Uchiyama
- Department of Anatomy, The Jikei University School of Medicine, Tokyo, Japan.,Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
| | - Norifumi Tatsumi
- Department of Anatomy, The Jikei University School of Medicine, Tokyo, Japan
| | - Sahoko Kamejima
- Department of Anatomy, The Jikei University School of Medicine, Tokyo, Japan.,Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
| | - Tsuyoshi Waku
- Laboratory for Genetic Code, Graduate School of Life and Medical Sciences, Doshisha University, Kyotanabe, Japan
| | - Ichiro Ohkido
- Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
| | - Keitaro Yokoyama
- Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
| | - Takashi Yokoo
- Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
| | - Masataka Okabe
- Department of Anatomy, The Jikei University School of Medicine, Tokyo, Japan.
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18
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Abstract
Maintenance of a normal serum phosphate level depends on absorption in the gut, reabsorption and excretion by the kidney, and the flux between the extracellular and skeletal pools. Phosphate homeostasis is a coordinated, complex system of crosstalk between the bone, intestine, kidney, and parathyroid gland. Dysfunction of this system has serious clinical consequences in healthy individuals and those with conditions, such as CKD, in which hyperphosphatemia is associated with increased risks of cardiovascular morbidity and mortality. The last half-century of renal research has helped define the contribution of the parathyroid hormone, calcitriol, fibroblast growth factor 23, and Klotho in the regulation of phosphate. However, despite new discoveries and insights gained during this time, what remains unchanged is the recognition that phosphate retention is the initiating factor for the development of many of the complications observed in CKD, namely secondary hyperparathyroidism and bone and cardiovascular diseases. Controlling phosphate load remains the primary goal in the treatment of CKD. This review discusses the clinical effects of dysregulated phosphate metabolism, particularly in CKD, and its association with cardiovascular disease. The importance of early control of phosphate load in the treatment of CKD is emphasized, and the latest research in the treatment of phosphate retention is discussed.
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Affiliation(s)
- Cynthia S Ritter
- Renal Division, Washington University School of Medicine, St. Louis, Missouri
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19
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Zand L, Kumar R. Serum Parathyroid Hormone Concentrations and Clinical Outcomes in ESRD: A Call for Targeted Clinical Trials. Semin Dial 2015; 29:184-8. [PMID: 26676210 DOI: 10.1111/sdi.12457] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Secondary hyperparathyroidism almost universally accompanies end-stage renal disease (ESRD). In some, but not all studies, elevated serum parathyroid hormone (PTH) concentrations are associated with increased fracture rates, cardiovascular disease, and mortality in ESRD. The serum concentration of PTH required for optimal bone health and reduced cardiovascular risk in such patients remains elusive. Recent clinical trials have failed to show substantial changes in morbidity and mortality following reductions of elevated serum PTH concentrations. In this review, we will assess some of the difficulties in evaluating elevated serum PTH concentrations, and their association with skeletal fractures and mortality in ESRD patients. We are of the opinion that in the context of ESRD, elevated PTH concentrations occur in conjunction with other comorbid conditions such as diabetes mellitus, malnutrition, hypertension, volume excess, preexisting heart disease, all of which have prevented establishing a precise association between elevated serum PTH concentrations and global or skeletal outcomes. Age, gender, and racial variability among groups make interpretation exceptionally difficult. Analysis of prevalent ESRD populations with secondary hyperparathyroidism should take all these factors into account. We suggest that future clinical trials which examine the usefulness of reductions in serum PTH concentrations be conducted in age, sex, and racially balanced groups, without or with minimal coexisting confounding disease. Furthermore, trials in such populations should have as their primary outcome a reduction in fractures rather than an alteration in mortality.
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Affiliation(s)
- Ladan Zand
- Division of Nephrology and Hypertension, Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota
| | - Rajiv Kumar
- Division of Nephrology and Hypertension, Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota.,Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota
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Mary A, Hénaut L, Boudot C, Six I, Brazier M, Massy ZA, Drüeke TB, Kamel S, Mentaverri R. Calcitriol prevents in vitro vascular smooth muscle cell mineralization by regulating calcium-sensing receptor expression. Endocrinology 2015; 156:1965-74. [PMID: 25763635 DOI: 10.1210/en.2014-1744] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Vascular calcification (VC) is a degenerative disease that contributes to cardiovascular morbidity and mortality. A negative relationship has been demonstrated between VC and calcium sensing receptor (CaSR) expression in the vasculature. Of interest, vitamin D response elements, which allow responsiveness to 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], are present in the promoters of the CaSR gene. We hypothesized that 1,25(OH)2D3, by modulating CaSR expression in vascular smooth muscle cells (VSMCs), might protect against VC. Human VSMCs were exposed to increasing concentrations of 1,25(OH)2D3 (0.01-10 nmol/L) in noncalcifying (1.8 mmol/L) or procalcifying Ca(2+)0 condition (5.0 mmol/L). Using quantitative RT-PCR and Western blotting we observed a significant increase in both CaSR mRNA and protein levels after exposure to 1.0 nmol/L 1,25(OH)2D3. This effect was associated with a maximal increase in CaSR expression at the cell surface after 48 hours of 1,25(OH)2D3 treatment, as assessed by flow cytometry. Down-regulation of the vitamin D receptor by small interfering RNA abolished these effects. In the procalcifying condition, 1.0 nmol/L 1,25(OH)2D3 blocked the Ca(2+)0-induced decrease in total and surface CaSR expression and protected against mineralization. Down-regulation of CaSR expression by CaSR small interfering RNA abolished this protective effect. 1,25(OH)2D3 concentrations of 0.5 and 5.0 nmol/L were also effective, but other (0.01, 0.1, and 10 nmol/L) concentrations did not modify CaSR expression and human VSMC mineralization. In conclusion, these findings suggest that nanomolar concentrations of 1,25(OH)2D3 induce a CaSR-dependent protection against VC. Both lower and higher concentrations are either ineffective or may even promote VC. Whether this also holds true in the clinical setting requires further study.
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Affiliation(s)
- Aurélien Mary
- INSERM Unit 1088 (A.M., L.H., C.B., I.B., M.B., Z.A.M., T.B.D., S.K., R.M.), University of Picardie Jules Vernes, 80000 Amiens, France; Department of Pharmacy (A.M.) and Department of Biochemistry (M.B., S.K., R.M.), Amiens University Medical Center, 80054 Amiens, France; Division of Nephrology (Z.A.M.), Ambroise Paré University Hospital, Assistance Publique-Hôpitaux de Paris, University Versailles Saint-Quentin-en-Yvelines, 92100 Boulogne Billancourt/Paris, France; and Multifaceted CaSR Initial Training Network (M.B., Z.A.M., S.K., R.M.)
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21
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Atchison DK, Harding P, Beierwaltes WH. Vitamin D increases plasma renin activity independently of plasma Ca2+ via hypovolemia and β-adrenergic activity. Am J Physiol Renal Physiol 2013; 305:F1109-17. [PMID: 23926179 DOI: 10.1152/ajprenal.00010.2013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
1, 25-Dihydroxycholechalciferol (calcitriol) and 19-nor-1, 25-dihydroxyvitamin D2 (paricalcitol) are vitamin D receptor (VDR) agonists. Previous data suggest VDR agonists may actually increase renin-angiotensin activity, and this has always been assumed to be mediated by hypercalcemia. We hypothesized that calcitriol and paricalcitol would increase plasma renin activity (PRA) independently of plasma Ca(2+) via hypercalciuria-mediated polyuria, hypovolemia, and subsequent increased β-adrenergic sympathetic activity. We found that both calcitriol and paricalcitol increased PRA threefold (P < 0.01). Calcitriol caused hypercalcemia, but paricalcitol did not. Both calcitriol and paricalcitol caused hypercalciuria (9- and 7-fold vs. control, P < 0.01) and polyuria (increasing 2.6- and 2.2-fold vs. control, P < 0.01). Paricalcitol increased renal calcium-sensing receptor (CaSR) expression, suggesting a potential cause of paricalcitol-mediated hypercalciuria and polyuria. Volume replacement completely normalized calcitriol-stimulated PRA and lowered plasma epinephrine by 43% (P < 0.05). β-Adrenergic blockade also normalized calcitriol-stimulated PRA. Cyclooxygenase-2 inhibition had no effect on calcitriol-stimulated PRA. Our data demonstrate that vitamin D increases PRA independently of plasma Ca(2+) via hypercalciuria, polyuria, hypovolemia, and increased β-adrenergic activity.
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Affiliation(s)
- Douglas K Atchison
- Dept. of Internal Medicine, Hypertension and Vascular Research Div., Henry Ford Hospital, 7121 E&R Bldg., 2799 W. Grand Blvd., Detroit, MI 48202.
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He Y, Perry B, Bi M, Sun H, Zhao T, Li Y, Sun C. Allosteric regulation of the calcium-sensing receptor in obese individuals. Int J Mol Med 2013; 32:511-8. [PMID: 23740560 DOI: 10.3892/ijmm.2013.1408] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Accepted: 05/24/2013] [Indexed: 11/06/2022] Open
Abstract
We have previously reported that the calcium-sensing receptor (CaSR) plays an important role in modulating lipid metabolism under low calcium conditions. The aim of this study was to identify possible regulators of CaSR and the mechanisms of action of CaSR in obese individuals. Subcutaneous fat samples were obtained from 10 obese and 10 non-obese males undergoing elective abdominal surgery. Visceral fat pads were obtained from 12 obese and 12 non-obese male rats. Serum lipid, tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) concentrations, as well as the gene and protein expression of CaSR in the white adipose tissue of obese subjects and rats were determined. Serum total calcium, vitamin D, parathyroid hormone (PTH) and amino acid levels in human subjects were measured. Intracellular calcium and cyclic adenosine monophosphate (cAMP) levels in rat adipocytes were measured by laser scanning confocal microscopy and ELISA, respectively. The results revealed that serum triglyceride (TG), total cholesterol (TC), low density lipoprotein-cholesterol (LDL-C), TNF-α, IL-6 and PTH levels were significantly higher in the obese individuals versus the controls. By contrast, serum vitamin D and amino acid concentrations were lower in the obese individuals versus the controls. In addition, intracellular calcium levels were higher, while cAMP levels were lower in the obese rat adipocytes compared with the control group. However, the gene and protein expression of CaSR in white adipose tissue did not differ between the obese groups and the controls. Thus, these results suggest that CaSR functions not through its expression, but rather through allosteric regulation in obese individuals.
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Affiliation(s)
- Yonghan He
- National Key Discipline of Nutrition and Food Hygiene, Public Health College, Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China
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Epigenetic Methylation of Parathyroid CaR and VDR Promoters in Experimental Secondary Hyperparathyroidism. Int J Nephrol 2012; 2012:123576. [PMID: 23094155 PMCID: PMC3474253 DOI: 10.1155/2012/123576] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Accepted: 09/04/2012] [Indexed: 11/25/2022] Open
Abstract
Secondary hyperparathyroidism (s-HPT) in uremia is characterized by decreased expression in the parathyroids of calcium sensing (CaR) and vitamin D receptors (VDR). Parathyroid hormone (PTH) is normalized despite low levels of CaR and VDR after experimental reversal of uremia. The expression of CaR in parathyroid cultures decreases rapidly. Methylation of promoter regions is often detected during epigenetic downregulation of gene expression. Therefore, using an experimental rat model, we examined changes in methylation levels of parathyroid CaR and VDR promoters in vivo and in vitro. Methods. Uremia was induced by 5/6 nephrectomy. Melting temperature profiling of CaR and VDR PCR products after bisulfite treatment of genomic DNA from rat parathyroids was performed. Real-time PCR measured expression of PTH, CaR, VDR, and klotho genes in vitro. Results. Parathyroids from uremic rats had similar low levels of methylation in vivo and in vitro. In culture, a significant downregulation of CaR, VDR, and klotho within two hours of incubation was observed, while housekeeping genes remained stable for 24 hours. Conclusion. In uremic s-HPT and in vitro, no overall changes in methylation levels in the promoter regions of parathyroid CaR and VDR genes were found. Thus, epigenetic methylation of these promoters does not explain decreased parathyroid expression of CaR and VDR genes in uremic s-HPT.
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Medical and Surgical Management (Including Diet). Clin Rev Bone Miner Metab 2012. [DOI: 10.1007/s12018-011-9116-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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Ritter CS, Haughey BH, Miller B, Brown AJ. Differential gene expression by oxyphil and chief cells of human parathyroid glands. J Clin Endocrinol Metab 2012; 97:E1499-505. [PMID: 22585091 PMCID: PMC3591682 DOI: 10.1210/jc.2011-3366] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Parathyroid oxyphil cells, whose function is unknown, are thought to be derived from chief cells. Oxyphil cells increase in number in parathyroid glands of patients with chronic kidney disease (CKD) and are even more abundant in patients receiving treatment for hyperparathyroidism with calcitriol and/or the calcimimetic cinacalcet. OBJECTIVE We examined oxyphil and chief cells of parathyroid glands of CKD patients for differential expression of genes important to parathyroid function. DESIGN/SETTING/PARTICIPANTS Parathyroid tissue from CKD patients with refractory hyperparathyroidism was immunostained for gene expression studies. MAIN OUTCOME MEASURE Immunostaining for PTH, PTHrP, calcium-sensing receptor, glial cells missing 2, vitamin D receptor, 25-hydroxyvitamin D-1α-hydroxylase, and cytochrome c was quantified and expression reported for oxyphil and chief cells. RESULTS Expression of all proteins analyzed, except for the vitamin D receptor, was higher in oxyphil cells than in chief cells. CONCLUSION Human parathyroid oxyphil cells express parathyroid-relevant genes found in the chief cells and have the potential to produce additional autocrine/paracrine factors, such as PTHrP and calcitriol. Additional studies are warranted to define the secretory properties of these cells and clarify their role in parathyroid pathophysiology.
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Affiliation(s)
- Cynthia S Ritter
- Renal Division, Washington University School of Medicine, Barnes Jewish Hospital, St Louis, Missouri 63110, USA
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Ritter CS, Haughey BH, Armbrecht HJ, Brown AJ. Distribution and regulation of the 25-hydroxyvitamin D3 1α-hydroxylase in human parathyroid glands. J Steroid Biochem Mol Biol 2012; 130:73-80. [PMID: 22326730 DOI: 10.1016/j.jsbmb.2012.01.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Revised: 01/12/2012] [Accepted: 01/20/2012] [Indexed: 01/22/2023]
Abstract
Parathyroid glands express the 25-hydroxyvitamin D(3) 1α-hydroxylase (1αOHase). 1,25-dihydroxyvitamin D(3) (calcitriol) synthesized by extrarenal tissues generally does not enter the circulation, but plays an autocrine/paracrine role specific to the cell type, and is regulated by the needs of that particular cell. While the role of calcitriol produced in the parathyroid glands presumably is to suppress PTH and cell growth, its regulation in this cell type has not been defined. In the present study, we found that regulation of the human parathyroid 1αOHase differs from the renal enzyme in that it is induced by FGF-23 and extracellular calcium. Hyperplastic parathyroid glands from patients with chronic kidney failure normally display a heterogeneous cellularity. We found that the 1αOHase is expressed at much higher levels in oxyphil cells than in chief cells in these patients. Recent findings indicate that oxyphil cell content is increased by treatment with calcium receptor activators (calcimimetics). Here, we demonstrate that the calcimimetic cinacalcet increases the expression of 1αOHase in human parathyroid cultures. Additionally, we found that the 1αOHase in human parathyroid cultures is functionally active, as evidenced by the ability of the enzyme to 1-hydroxylate 25(OH)D(3) in parathyroid monolayers. Calcium, as well as cinacalcet, also induced expression of the degradation enzyme 24-hydroxylase, indicating the presence of a negative feedback system in the parathyroid cells. Therefore, local production of 1αOHase suggests an autocrine/paracrine role in regulating parathyroid function and may mediate, in part, the suppression of PTH by calcium and FGF-23.
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Affiliation(s)
- Cynthia S Ritter
- Renal Division, Washington University School of Medicine, St. Louis, MO 63110, United States.
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Román-García P, Carrillo-López N, Naves-Díaz M, Rodríguez I, Ortiz A, Cannata-Andía JB. Dual-specificity phosphatases are implicated in severe hyperplasia and lack of response to FGF23 of uremic parathyroid glands from rats. Endocrinology 2012; 153:1627-37. [PMID: 22334717 DOI: 10.1210/en.2011-1770] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Phosphate load accelerates the progression of secondary hyperparathyroidism (sHPT). In advanced stages of sHPT, there is a marked hyperplasia and resistance to classical regulatory endocrine factors such as calcium, calcitriol, or fibroblast growth factor 23 (FGF23), which suppresses PTH secretion by an ERK-dependent mechanism. Nephrectomized rats were fed with a high- or normal-phosphorus diet for different periods of time to induce sHPT. Biochemical parameters, parathyroid gland microarrays, quantitative real-time PCR, and immunohistochemistry (ERK/phospho-ERK) were performed. To test the role of dual-specificity phosphatases (Dusp) on parathyroid gland regulation, normal parathyroid glands were cultured with FGF23 and Dusp. Uremic rats fed with a high-phosphorus diet showed more severe sHPT, higher serum FGF23 levels and mortality, and decreased parathyroid Klotho gene expression. In all stages of sHPT, parathyroid microarrays displayed a widespread gene expression down-regulation; only a few genes were overexpressed, among them, Dusp5 and -6. In very severe sHPT, a significant reduction in phospho-ERK (the target of Dusp) and a significant increase of Dusp5 and -6 gene expression were observed. In ex vivo experiments with parathyroid glands, Dusp partially blocked the effect of FGF23 on PTH secretion, suggesting that Dusp might play a role in parathyroid regulation. The overexpression of Dusp and the inactivation of ERK found in the in vivo studies together with the ex vivo results might be indicative of the defense mechanism triggered to counteract hyperplasia, a mechanism that can also contribute to the resistance to the effect of FGF23 on parathyroid gland observed in advanced forms of chronic kidney disease.
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Affiliation(s)
- Pablo Román-García
- Servicio de Metabolismo Óseo y Mineral, Instituto Reina Sofía de Investigaciones Nefrológicas, Hospital Universitario Central de Asturias, 33006 Oviedo, Asturias, Spain
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Miller G, Davis J, Shatzen E, Colloton M, Martin D, Henley CM. Cinacalcet HCl prevents development of parathyroid gland hyperplasia and reverses established parathyroid gland hyperplasia in a rodent model of CKD. Nephrol Dial Transplant 2011; 27:2198-205. [PMID: 22036941 PMCID: PMC3363978 DOI: 10.1093/ndt/gfr589] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Secondary hyperparathyroidism (sHPT) represents an adaptive response to progressively impaired control of calcium, phosphorus and vitamin D in chronic kidney disease (CKD). It is characterized by parathyroid hyperplasia and excessive synthesis and secretion of parathyroid hormone (PTH). Parathyroid hyperplasia in uremic rats can be prevented by calcium-sensing receptor (CaSR) activation with the calcimimetic cinacalcet (Sensipar®/Mimpara®); however, it is unknown, how long the effects of cinacalcet persist after withdrawal of treatment or if cinacalcet is efficacious in uremic rats with established sHPT. METHODS We sought to determine the effect of cinacalcet discontinuation in uremic rats and whether cinacalcet was capable of influencing parathyroid hyperplasia in animals with established sHPT. RESULTS Discontinuation of cinacalcet resulted in reversal of the beneficial effects on serum PTH and parathyroid hyperplasia. In rats with established sHPT, cinacalcet decreased serum PTH and mediated regression of parathyroid hyperplasia. The cinacalcet-mediated decrease in parathyroid gland size was accompanied by increased expression of the cyclin-dependent kinase inhibitor p21. Prevention of cellular proliferation with cinacalcet occurred despite increased serum phosphorus and decreased serum calcium. CONCLUSIONS The animal data provided suggest established parathyroid hyperplasia can be reversed by modulating CaSR activity with cinacalcet and that continued treatment may be necessary to maintain reductions in PTH.
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Affiliation(s)
- Gerald Miller
- Department of Metabolic Disorders, Amgen Inc, Thousand Oaks, CA, USA
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Imanishi Y, Kawata T, Kenko T, Wada M, Nagano N, Miki T, Arnold A, Inaba M. Cinacalcet HCl suppresses Cyclin D1 oncogene-derived parathyroid cell proliferation in a murine model for primary hyperparathyroidism. Calcif Tissue Int 2011; 89:29-35. [PMID: 21541686 DOI: 10.1007/s00223-011-9490-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2011] [Accepted: 03/31/2011] [Indexed: 10/18/2022]
Abstract
Cinacalcet HCl (cinacalcet) is a calcimimetic compound, which suppresses parathyroid (PTH) hormone secretion from parathyroid glands in both primary hyperparathyroidism (PHPT) and secondary hyperparathyroidism (SHPT). We previously reported the suppressive effect of cinacalcet on PTH secretion in vivo in a PHPT model mouse, in which parathyroid-targeted overexpression of the cyclin D1 oncogene caused chronic biochemical hyperparathyroidism and parathyroid cell hyperplasia. Although cinacalcet suppressed parathyroid cell proliferation in SHPT in 5/6-nephrectomized uremic rats, its effect on PHPT has not yet been determined. In this study, the effect of cinacalcet on parathyroid cell proliferation was analyzed in PHPT mice. Cinacalcet (1 mg/g) was mixed into the rodent diet and orally administrated to 80-week-old PHPT mice for 10 days before death. 5-Bromo-2'-deoxyuridine (BrdU, 6 mg/day) was infused by an osmotic pump for 5 days before death, followed by immunostaining of the thyroid-parathyroid complex using an anti-BrdU antibody to estimate parathyroid cell proliferation. Compared to untreated PHPT mice, cinacalcet significantly suppressed both serum calcium and PTH. The proportion of BrdU-positive cells to the total cell number in the parathyroid glands increased considerably in untreated PHPT mice (9.5 ± 3.1%) compared to wild-type mice (0.7 ± 0.1%) and was significantly suppressed by cinacalcet (1.2 ± 0.2%). Cinacalcet did not affect apoptosis in the parathyroid cells of PHPT mice. These data suggest that cinacalcet suppressed both serum PTH levels and parathyroid cell proliferation in vivo in PHPT.
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Affiliation(s)
- Yasuo Imanishi
- Department of Metabolism, Endocrinology and Molecular Medicine, Osaka City University Graduate School of Medicine, 1-4-3, Asahi-machi, Abeno-ku, Osaka, 545-8585, Japan.
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Mpio I, Boumendjel N, Karaaslan H, Arkouche W, Lenz A, Cardozo C, Cardozo J, Pastural-Thaunat M, Fouque D, Silou J, Attaf D, Laville M. Hyperparathyroïdie secondaire et anémie. Effets d’un calcimimétique sur le contrôle de l’anémie des hémodialysés chroniques. Étude pilote. Nephrol Ther 2011; 7:229-36. [DOI: 10.1016/j.nephro.2011.01.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2010] [Revised: 01/16/2011] [Accepted: 01/16/2011] [Indexed: 10/18/2022]
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Torres PU. Calcimimétiques : physiologie, résultats d’études cliniques et perspectives. Nephrol Ther 2011; 7:99-104. [DOI: 10.1016/j.nephro.2010.12.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2010] [Revised: 12/20/2010] [Accepted: 12/21/2010] [Indexed: 11/29/2022]
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Cunningham J, Locatelli F, Rodriguez M. Secondary hyperparathyroidism: pathogenesis, disease progression, and therapeutic options. Clin J Am Soc Nephrol 2011; 6:913-21. [PMID: 21454719 DOI: 10.2215/cjn.06040710] [Citation(s) in RCA: 364] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Secondary hyperparathyroidism (SHPT) is a challenge frequently encountered in the management of patients with chronic kidney disease (CKD). Downregulation of the parathyroid vitamin D and calcium-sensing receptors represent critical steps that lead to abnormalities in mineral metabolism: high phosphate, low calcium, and vitamin D deficiency. These imbalances result in parathyroid hyperplasia and contribute to vascular calcification. New studies have established a central role for fibroblast growth factor 23 (FGF-23) in the regulation of phosphate-vitamin D homeostasis. FGF-23 concentration increases in CKD and contributes to SHPT. Achieving current targets for the key mineral parameters in the management of SHPT set by the Kidney Disease Improving Global Outcomes (KDIGO) guidelines can be challenging. This review summarizes the current understanding and evidence supporting strategies for SHPT treatment in CKD patients. Treatment should include a combination of dietary phosphorus restriction, phosphate binders, vitamin D sterols, and calcimimetics. Parathyroidectomy is effective in suitable candidates refractory to medical therapy and the standard against which new approaches should be measured. Future strategies may focus on the stimulation of apoptotic activity of hyperplastic parathyroid cells.
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Affiliation(s)
- John Cunningham
- Centre for Nephrology, UCL Medical School, Royal Free Campus, London, United Kingdom
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Kumar R, Thompson JR. The regulation of parathyroid hormone secretion and synthesis. J Am Soc Nephrol 2010; 22:216-24. [PMID: 21164021 DOI: 10.1681/asn.2010020186] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Secondary hyperparathyroidism classically appears during the course of chronic renal failure and sometimes after renal transplantation. Understanding the mechanisms by which parathyroid hormone (PTH) synthesis and secretion are normally regulated is important in devising methods to regulate overactivity and hyperplasia of the parathyroid gland after the onset of renal insufficiency. Rapid regulation of PTH secretion in response to variations in serum calcium is mediated by G-protein coupled, calcium-sensing receptors on parathyroid cells, whereas alterations in the stability of mRNA-encoding PTH by mRNA-binding proteins occur in response to prolonged changes in serum calcium. Independent of changes in intestinal calcium absorption and serum calcium, 1α,25-dihydroxyvitamin D also represses the transcription of PTH by associating with the vitamin D receptor, which heterodimerizes with retinoic acid X receptors to bind vitamin D-response elements within the PTH gene. 1α,25-Dihydroxyvitamin D additionally regulates the expression of calcium-sensing receptors to indirectly alter PTH secretion. In 2°HPT seen in renal failure, reduced concentrations of calcium-sensing and vitamin D receptors, and altered mRNA-binding protein activities within the parathyroid cell, increase PTH secretion in addition to the more widely recognized changes in serum calcium, phosphorus, and 1α,25-dihydroxyvitamin D. The treatment of secondary hyperparathyroidism by correction of serum calcium and phosphorus concentrations and the administration of vitamin D analogs and calcimimetic agents may be augmented in the future by agents that alter the stability of mRNA-encoding PTH.
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Affiliation(s)
- Rajiv Kumar
- Division of Nephrology and Hypertension, Departments of Medicine, Biochemistry and Molecular Biology, Mayo Clinic and Foundation, 200 1 Street SW, Rochester, MN 55905, USA.
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Shiizaki K, Hatamura I, Fukagawa M, Nakazawa E, Saji F, Watanabe Y, Akizawa T, Kusano E. Development of a technique for introduction of an expressed complementary deoxyribonucleic acid into parathyroid cells by direct injection. Endocrinology 2010; 151:4031-8. [PMID: 20519369 DOI: 10.1210/en.2010-0012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
PTH is a major mediator of bone and mineral metabolism. However, physiological and pathological investigations of parathyroid cells (PTCs) have been limited because of the lack of available cell lines and because the organ is too small for detailed studies. Here, we describe a novel method for adenovirus-mediated cDNA transfer into PTCs, and we show the accuracy of the method in a rat model of uremia-induced secondary hyperparathyroidism. Rats underwent a 5/6-nephrectomy and were fed with a high-phosphate diet for 8 wk. The parathyroid glands were surgically exposed and adenoviruses containing LacZ or Ca-sensing receptor (CaSR) were directly injected into the glands under a zoom-stereo microscope. The parathyroid glands were analyzed for infection of adenovirus and immunohistochemically for expression of CaSR. The functional activity of exogenous CaSR in PTCs after this treatment was investigated based on changes of the calcium and PTH curve. A virus concentration of more than 10(9) plaque-forming units/ml was required for adequate infection of PTCs within 7 d after treatment. Marked increase of CaSR-positive PTCs by 2.39 +/- 0.72 times relative to control treatment, and significant colocalization of CaSR overexpression and virus labeling, were observed in glands after gene introduction. The calcium and PTH curve was shifted to the left from the basal position (set point, 1.10 +/- 0.09 to 0.76 +/- 0.12 mm; P < 0.0001), indicating successful introduction of a functionally active cDNA into the PTCs. This technique may facilitate an elucidation of biological effects through targeting and identification of specific features of PTCs, which may provide the basis for new clinical approaches.
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MESH Headings
- Adenoviridae/genetics
- Animals
- DNA, Complementary/administration & dosage
- DNA, Complementary/analysis
- DNA, Complementary/genetics
- DNA, Complementary/metabolism
- Disease Models, Animal
- Expressed Sequence Tags
- Gene Transfer Techniques
- Genetic Vectors/administration & dosage
- Hyperparathyroidism, Secondary/genetics
- Hyperparathyroidism, Secondary/pathology
- Injections/methods
- Lac Operon
- Models, Biological
- Osmolar Concentration
- Parathyroid Glands/cytology
- Parathyroid Glands/metabolism
- Rats
- Rats, Sprague-Dawley
- Rats, Transgenic
- Receptors, Calcium-Sensing/administration & dosage
- Receptors, Calcium-Sensing/genetics
- Receptors, Calcium-Sensing/metabolism
- Uremia/genetics
- Uremia/pathology
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Affiliation(s)
- Kazuhiro Shiizaki
- Division of Nephrology, Department of Internal Medicine, Jichi Medical University, Shimotsuke, Tochigi, Japan.
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Canalejo R, Canalejo A, Martinez-Moreno JM, Rodriguez-Ortiz ME, Estepa JC, Mendoza FJ, Munoz-Castaneda JR, Shalhoub V, Almaden Y, Rodriguez M. FGF23 fails to inhibit uremic parathyroid glands. J Am Soc Nephrol 2010; 21:1125-35. [PMID: 20431039 PMCID: PMC3152229 DOI: 10.1681/asn.2009040427] [Citation(s) in RCA: 150] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2009] [Accepted: 02/11/2010] [Indexed: 12/22/2022] Open
Abstract
Fibroblast growth factor 23 (FGF23) modulates mineral metabolism by promoting phosphaturia and decreasing the production of 1,25-dihydroxyvitamin D(3). FGF23 decreases parathyroid hormone (PTH) mRNA and secretion, but despite a marked elevation in FGF23 in uremia, PTH production increases. Here, we investigated the effect of FGF23 on parathyroid function in normal and uremic hyperplastic parathyroid glands in rats. In normal parathyroid glands, FGF23 decreased PTH production, increased expression of both the parathyroid calcium-sensing receptor and the vitamin D receptor, and reduced cell proliferation. Furthermore, FGF23 induced phosphorylation of extracellular signal-regulated kinase 1/2, which mediates the action of FGF23. In contrast, in hyperplastic parathyroid glands, FGF23 did not reduce PTH production, did not affect expression of the calcium-sensing receptor or vitamin D receptor, and did not affect cell proliferation. In addition, FGF23 failed to activate the extracellular signal-regulated kinase 1/2-mitogen-activated protein kinase pathway in hyperplastic parathyroid glands. We observed very low expression of the FGF23 receptor 1 and the co-receptor Klotho in uremic hyperplastic parathyroid glands, which may explain the lack of response to FGF23 in this tissue. In conclusion, in hyperparathyroidism secondary to renal failure, the parathyroid cells resist the inhibitory effects of FGF23, perhaps as a result of the low expression of FGF23 receptor 1 and Klotho in this condition.
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Affiliation(s)
- Rocío Canalejo
- Unidad de Investigacion, Servicio de Nefrologia, Departamento de Medicina, Red in ren, Instituto Maimó nides de Invstigación Biomédica de Córdoba, Hospital Universitario Reina Sofia, Cordoba, Spain
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Carrillo-López N, Fernández-Martín JL, Alvarez-Hernández D, González-Suárez I, Castro-Santos P, Román-García P, López-Novoa JM, Cannata-Andía JB. Lanthanum activates calcium-sensing receptor and enhances sensitivity to calcium. Nephrol Dial Transplant 2010; 25:2930-7. [PMID: 20233740 DOI: 10.1093/ndt/gfq124] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The aim of this study was to investigate whether nanomolar concentrations of lanthanum could influence the calcium-sensing receptor (CaSR) response. METHODS Embryonic kidney (HEK-293) cells transiently transfected with the human CaSR were used to test the ability of lanthanum to activate the CaSR, either alone or in combination with calcium. CaSR activation was measured by flow cytometry. Parathyroid glands from 4-month-old male Wistar rats with normal renal function (n = 60) were also cultured ex vivo with different concentrations of lanthanum to measure parathyroid hormone (PTH) secreted to the medium and PTH mRNA. RESULTS The maximal CaSR activation induced by 1 muM lanthanum chloride (LaCl(3)) was similar to that induced by 16 mM calcium chloride (CaCl(2) 16 mM: 294 +/- 14%; LaCl(3) 1 muM: 303 +/- 11%). Lanthanum half effective concentration (EC(50)) was 77.28 nM, lower than the 2.30 mM obtained for calcium, supporting the concept that this metal is a strong agonist of the CaSR. Moreover, lanthanum was also able to enhance CaSR sensitivity to calcium. The presence of 1 nM LaCl(3) significantly left-shifted the CaSR response curve, changing the EC(50) value for calcium from 2.30 mM (calcium alone) to 1.26 mM (calcium + 1 nM lanthanum). The parathyroid glands cultured with lanthanum showed a trend to secrete less PTH compared to the control glands: 1.51 +/- 0.23 (control), 0.91 +/- 0.17 (La 100 nM) and 1.04 +/- 0.18 (La 400 nM) [(pg/h)/(pg/h), mean +/- SEM] (ANOVA P = 0.0145). A similar trend was also observed in PTH synthesis measured by PTH mRNA levels. CONCLUSIONS These in vitro findings demonstrate that lanthanum, at nanomolar concentrations, is an agonist of the CaSR able to activate it in the absence of calcium. In addition, it can also enhance CaSR sensitivity to calcium, modulating PTH synthesis and secretion.
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Affiliation(s)
- Natalia Carrillo-López
- Bone and Mineral Research Unit, Instituto Reina Sofía de Investigación, REDinREN del ISCIII, Hospital Universitario Central de Asturias, Universidad de Oviedo, C/Julián Clavería s/n, 33006 Oviedo, Spain
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Alvarez-Hernández D, González-Suárez I, Fernández-Martín JL, Rodríguez I, Santamaría I, Coto E, Cannata-Andía JB. Residue 826 in the calcium-sensing receptor is implicated in the response to calcium and to R-568 calcimimetic compound. Calcif Tissue Int 2010; 86:227-33. [PMID: 20130845 DOI: 10.1007/s00223-009-9298-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Accepted: 09/08/2009] [Indexed: 11/26/2022]
Abstract
Within the extracellular loops of the seven-transmembrane domain of the calcium-sensing receptor (CaR) there is a region (I819-E837) relevant for calcimimetic activity. As the naturally occurring variant Ala826Thr is within this important region, it may be postulated that this change may influence the CaR response to calcium and R-568. Human embryonic kidney (HEK-293) cells transiently transfected with three different human CaRs (wild-type [A826], variant allele [T826], and artificial mutant [W826]) were used to test the ability of calcium alone or in combination with the calcimimetic R-568 to modulate CaR activity. CaR activation was detected by flow cytometry using a fluorescent probe. Intracellular calcium changes were measured in response to changes in extracellular calcium alone or with different R-568 concentrations. The change of the alanine in the 826 position (A826) for threonine (T826) worsened calcium sensitivity, increasing the EC(50) value from 2.34 +/- 0.48 mM (A826, wild-type) to 2.96 +/- 0.75 mM (T826) (P < 0.05). The T826 receptor reached a similar response with 1 muM R-568 compared with the wild-type receptor. On the contrary, the artificial introduction of a tryptophan in the same position (W826) did not affect calcium sensitivity (EC(50) = 2.64 +/- 0.81 mM) but reduced the ability of the receptor to respond to R-568. The results demonstrate the importance of the 826 residue in the CaR response to calcium and calcimimetics. Since the A826T change was described as a natural variant, the differences in the calcium and calcimimetic responses observed between the alleles could have potential clinical impact.
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Affiliation(s)
- Daniel Alvarez-Hernández
- Bone and Mineral Research Unit, Servicio de Metabolismo Oseo y Mineral, Hospital Universitario Central de Asturias, Instituto Reina Sofía de Investigación, RedinRen del ISCIII, Universidad de Oviedo, C/ Julián Clavería s/n, 33006 Oviedo, Spain.
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Carrillo-López N, Román-García P, Fernández-Martín JL, Cannata-Andía JB. Parathyroid gland regulation: contribution of thein vivoandin vitromodels. Expert Opin Drug Discov 2010; 5:265-75. [DOI: 10.1517/17460441003615170] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Natalia Carrillo-López
- Hospital Universitario Central de Asturias, Bone and Mineral Research Unit, Instituto Reina Sofía de Investigación, REDinREN del ISCIII, Universidad de Oviedo, C/Julián Clavería s/n, Oviedo 33006, Asturias, Spain +34 985106137 ; +34 985106142 ;
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Canalejo A, Canalejo R, Rodriguez ME, Martinez-Moreno JM, Felsenfeld AJ, Rodríguez M, Almaden Y. Development of parathyroid gland hyperplasia without uremia: role of dietary calcium and phosphate. Nephrol Dial Transplant 2009; 25:1087-97. [PMID: 19934096 DOI: 10.1093/ndt/gfp616] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Background. Many experimental studies have demonstrated that parathyroid cell proliferation is induced by uremia and further aggravated by hypocalcemia, phosphorus retention and vitamin D deficiency. However, these factors may also promote parathyroid growth without uremia. In the present study, we examined the onset and progression of parathyroid hyperplasia regardless of the uremic setting, a situation that might occur soon during the early renal disease. Thus, the novelty of this work resides in the close examination of the time course for the expected changes in proliferation rates and their association with parathyroid hormone (PTH) release in normal rats under the physiological demands of a high-phosphate diet (HPD) or a low-calcium diet (LCD). Methods. We evaluated the functional response of the parathyroid glands in normal rats to different physiological demands an HPD 0.6% Ca, 1.2% P) and LCD 0.2% Ca, 0.6% P) and compared it with that of uremic rats. Furthermore, we also evaluated the time course for the reversal of high-P and low-Ca-induced parathyroid cell growth and PTH upon normalization of dietary Ca and P intake (0.6% Ca, 0.6% P). Proliferation was measured by flow cytometry and calcium receptor (CaR) and vitamin D receptor (VDR) expression were assessed by qRT-PCR. Results. The pattern in the development of parathyroid hyperplasia by the two dietary models was different. The HPD produced a stronger stimulus than the number of proliferating cells doubled after only 1 day, while the LCD required 5 days to induce an increase; the elevated calcitriol might be a mitigating factor. The increase in cell proliferation was accompanied by a transient down-regulation of VDR expression (higher in the HPD); the expression of CaR was not affected by either diet. Cell proliferation and VDR mRNA levels were restored to control values by Day 15; it is as though the gland had attained a sufficient level of hyperplasia to respond to the PTH challenge. Compared to normal rats, the response of uremic rats to the HPD showed sustained and much higher rates of PTH secretion and cell proliferation and sustained down-regulation of both VDR mRNA and CaR mRNA. Finally, the recovery from the HPD or LCD to a control diet resulted in a rapid restoration of PTH values (1 to 2 days), but the reduction in cell proliferation was delayed (3 to 5 days). Conclusions. Regardless of uremia, a physiological demand to increase the PTH secretion driven either by a high P or a low Ca intake is able to induce a different pattern of parathyroid hyperplasia, which might be aggravated by the down-regulation of VDR expression. The recovery from the HPD or LCD to a control diet results in a more rapid reduction in PTH than in cell proliferation.
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Affiliation(s)
- Antonio Canalejo
- Department of Environmental Biology and Public Health, University of Huelva, Huelva, Spain
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Abstract
Glial cells missing-2 (Gcm2) is the key regulating transcription factor for parathyroid gland development. The continued expression of high levels of Gcm2 in mature parathyroid glands suggests that it is required for maintenance of parathyroid cell differentiation. The role of Gcm2 in parathyroid cell physiology, however, has not been fully studied. In this study, we examined the effects of Gcm2 silencing on cultured human parathyroid cells. Collagenase-dispersed human parathyroid cells from patients with chronic kidney disease were placed in monolayer cultures and infected with lentivirus expressing shRNA for human Gcm2. Seventy-two hours after infection, mRNA was processed and analyzed for Gcm2, PTH, vitamin D receptor (VDR), calcium-sensing receptor (CaR), 25-hydroxyvitamin D(3) 1-alpha-hydroxylase (1-OHase), and proliferating cell nuclear antigen (PCNA) by real-time PCR (qPCR). Protein expression of affected genes was analyzed by immunoblot 72 h after infection. Gcm2 mRNA and protein were decreased by 74.2 +/- 12.2% (SD; n = 3 experiments; p < 0.01) and 67.5 +/- 15.7% (n = 2; p < 0.01), respectively. CaR mRNA and protein were reduced by 47.8 +/- 21.1% (n = 3; p < 0.01) and 48.1 +/- 4.3% (n = 3; p < 0.01), respectively. However, VDR, PTH, 1-OHase, and PCNA were not significantly affected by Gcm2 silencing. Further analysis of CaR mRNA indicated that transcripts containing exon 1B, derived by transcription from CaR promoter 2, were downregulated (58.8 +/- 19.27%; n = 3; p < 0.05) by Gcm2 silencing. Exon 1A-containing transcripts from promoter 1 were expressed at very low levels in the cultures. These results indicate that one function of Gcm2 is to maintain high levels of CaR expression in parathyroid cells.
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Chong CK, Muzoora M, Eckert GJ, Kamalesh M, Moe SM. Medication changes based on echocardiography in dialysis patients. Hemodial Int 2009; 13:472-8. [PMID: 19552741 DOI: 10.1111/j.1542-4758.2009.00363.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Kidney/Disease Outcome Quality Initiative (K/DOQI) guidelines recommend baseline echocardiography at the initiation of dialysis and every 3 years thereafter in patients for early detection of cardiac disease to optimize medical therapy. Because dialysis patients are at increased cardiovascular risk and thus most are already on cardioprotective medications, we hypothesize that serial screening echocardiography will not alter cardioprotective medications in dialysis patients. Retrospective analysis of medication administration of 231 dialysis patients was conducted. Patients were divided into 2 groups, those with and those without echocardiograms. Medication changes post echocardiography were compared with subjects without echocardiograms at comparable time points. The primary end point was the number of medication class changes that occurred in 2 months post echocardiography. Medication classes examined were beta blockers (BB), angiotensin converting enzyme inhibitors or angiotensin receptor blockers (ACEI/ARB), nitrates, calcium channel blockers (CCB), and statins. In the Echo group, there were 29 (19%) subjects with at least 1 medication class change post echocardiography, compared with 121 (81%) subjects without change. The number of patients on specific medication classes before and after echocardiography were BB (90 [60%] vs. 97 [65%], P=0.05), ACEI/ARB (74 [49%] vs. 82 [55%], P=0.01), nitrates (34 [23%] vs. 33 [22%], P=0.56), CCB (77 [51%] vs. 79 [53%], P=0.56), and statins (69 [46%] vs. 70 [47%], P=0.71). When compared with the No Echo group, there was no significant change in number of any medication classes. The occurrence of medication changes post echocardiography in dialysis patients is low and is not different than changes in routine care of dialysis patients without echocardiograms. Thus, serial screening echocardiography may not have added benefit to optimizing medical management of cardiovascular disease in dialysis patients. Further studies are warranted to demonstrate evidence for the use of serial screening echocardiography in this high-risk population.
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Affiliation(s)
- Chun K Chong
- Indiana University School of Medicine, Indianapolis, Indiana 46202, USA
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Riccardi D, Finney BA, Wilkinson WJ, Kemp PJ. Novel regulatory aspects of the extracellular Ca2+-sensing receptor, CaR. Pflugers Arch 2009; 458:1007-22. [PMID: 19484257 DOI: 10.1007/s00424-009-0681-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Revised: 04/30/2009] [Accepted: 05/05/2009] [Indexed: 01/15/2023]
Abstract
The capacity to sense and adapt to changes in environmental cues is of paramount importance for every living organism. From yeast to man, cells must be able to match cellular activities to growth environment and nutrient availability. Key to this process is the development of membrane-bound systems that can detect modifications in the extracellular environment and to translate these into biological responses. Evidence gathered over the last 15 years has demonstrated that many of these cell surface "sensors" belong to the G protein-coupled receptor superfamily. Crucial to our understanding of nutrient sensing in mammalian species has been the identification of the extracellular Ca(2+)/cation-sensing receptor, CaR. CaR was the first ion-sensing molecule identified in man and genetic studies in humans have revealed the importance of the CaR in mineral ion metabolism. Latter, it has become apparent that the CaR also plays an important role outside the Ca(2+) homeostatic system, as an integrator of multiple environmental signals for the regulation of many vital cellular processes, from cell-to-cell communication to secretion and cell survival/cell death. Recently, novel aspects of receptor function reveal an unexpected role for the CaR in the regulation of growth and development in utero.
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Effects of calcium sources and soluble silicate on bone metabolism and the related gene expression in mice. Nutrition 2009; 25:581-9. [DOI: 10.1016/j.nut.2008.10.023] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2008] [Revised: 10/23/2008] [Accepted: 10/29/2008] [Indexed: 11/20/2022]
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Saidak Z, Mentaverri R, Brown EM. The role of the calcium-sensing receptor in the development and progression of cancer. Endocr Rev 2009; 30:178-95. [PMID: 19237714 DOI: 10.1210/er.2008-0041] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The calcium-sensing receptor (CaR) is responsive to changes in the extracellular Ca(2+) (Ca(2+)(o)) concentration. It is a member of the largest family of cell surface receptors, the G protein-coupled receptors, and it has been shown to be involved in Ca(2+)(o) homeostasis. Apart from its primary role in Ca(2+)(o) homeostasis, the CaR may be involved in phenomena that allow for the development of many types of benign or malignant tumors, from parathyroid adenomas to breast, prostate, and colon cancers. For example, whereas the CaR is expressed in both normal and malignant breast tissue, increased CaR levels have been reported in highly metastatic primary breast cancer cells and breast cancer cell lines, possibly contributing to their malignancy and associated alterations in their biological properties. In these settings the CaR exhibits oncogenic properties. Enhanced CaR expression and altered proliferation of prostate cancer cells in response to increased Ca(2+)(o) have also been described. In contrast, colon and parathyroid cancers often present with reduced or absent CaR expression, and activation of this receptor decreases cell proliferation, suggesting a role for the CaR as a tumor suppressor gene. Thus, the CaR may play an important role in the development of many types of neoplasia. Herein, we review the role of the CaR in various benign and malignant tumors in further detail, describing its contribution to parathyroid tumors, breast, prostate, and colon cancers, and we evaluate how pharmacological manipulations of this receptor may be of interest for the treatment of certain cancers in the future.
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Affiliation(s)
- Zuzana Saidak
- Institut National de la Santé et de la Recherche Médicale ERI-12, 1, Amiens, France.
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Messa P, Alfieri C, Brezzi B. Cinacalcet: pharmacological and clinical aspects. Expert Opin Drug Metab Toxicol 2009; 4:1551-60. [PMID: 19040330 DOI: 10.1517/17425250802587017] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The calcium sensing receptor (CaSR) is expressed in cells secreting calcium-regulating hormones, in cells involved in calcium transport and in many other tissues, with an as yet not completely defined role. In parathyroid cells, the CaSR stimulation inhibits parathyroid hormone (PTH) secretion, synthesis and parathyroid cell proliferation. Cinacalcet belongs to calcimimetic type II compounds that can interact with CaSR, increasing its affinity for calcium. Clinical studies have proved cinacalcet to be effective in reducing calcium and PTH levels in primary hyperparathyroidism and in reducing PTH, calcium and phosphate in patients with secondary hyperparathyroidism owing to chronic renal failure, with a relatively safe profile, the only reported adverse events being hypocalcaemia and gastrointestinal symptoms. However, though calcimimetics do represent a real advancement in the field of the treatment of PTH secretion disturbances, there is a need for clinical trials, which should aim to demonstrate that a better control of biochemical parameters is also matched with better clinical outcomes.
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Affiliation(s)
- Piergiorgio Messa
- Nefrologia, Dialisi e Trapianto, Padiglione Croff, Ospedale Maggiore-Policlinico, v. Commenda 15, 20122 Milano, Italy.
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Mendoza FJ, Lopez I, Canalejo R, Almaden Y, Martin D, Aguilera-Tejero E, Rodriguez M. Direct upregulation of parathyroid calcium-sensing receptor and vitamin D receptor by calcimimetics in uremic rats. Am J Physiol Renal Physiol 2008; 296:F605-13. [PMID: 19091789 DOI: 10.1152/ajprenal.90272.2008] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
To investigate whether the effect of the calcimimetic AMG 641 and calcitriol on CaSR and VDR expression could be separated from their ability to reduce parathyroid cell proliferation, five-sixth nephrectomized (5/6 Nx) rats received vehicle, AMG 641, calcitriol, or AMG 641+calcitriol either daily for 13 days (long-term protocol) or in a single dose (short-term protocol). In the long-term protocol, AMG 641, calcitriol, and their combination significantly reduced the percentage of proliferating parathyroid cells. Proliferation was uncontrolled in the short-term protocol. A significant increase in CaSR mRNA (% vs. beta-actin) was detected in rats treated with both calcitriol (1.60 +/- 0.30) and AMG 641 (1.66 +/- 0.25) for 13 days (P = 0.01 vs. 5/6 Nx+vehicle, 0.89 +/- 0.09); and there was a further increase when both drugs were administered simultaneously (2.46 +/- 0.33). In the short-term protocol, only rats receiving AMG 641 alone (2.01 +/- 0.33, P < 0.001) showed increased expression of CaSR mRNA, whereas the combination (1.81 +/- 0.20) produced no additional benefit. AMG 641 also increased CaSR mRNA expression in vitro. Changes in VDR mRNA paralleled those of CaSR mRNA. In the long-term treatment, both AMG 641 (0.87 +/- 0.14) and calcitriol (0.99 +/- 0.12) increased VDR mRNA (P < 0.05 vs. 5/6 Nx+vehicle, 0.49 +/- 0.10), and the increase was more accentuated when the drugs were combined (1.49 +/- 0.45). In the short-term protocol, only treatment with AMG 641, alone (1.52 +/- 0.41) or combined with calcitriol (1.86 +/- 0.24), increased VDR mRNA. In conclusion, our results demonstrate an acute increase in CaSR mRNA and VDR mRNA in the parathyroid glands of uremic rats treated with AMG 641, in which cell proliferation was uncontrolled, thus supporting a direct effect of calcimimetics on CaSR and VDR expression by hyperplastic parathyroid cells.
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Affiliation(s)
- Francisco J Mendoza
- Departamento Medicina y Cirugia Animal, Universidad de Cordoba, Cordoba, Spain
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Wetmore JB, Quarles LD. Treatment of secondary hyperparathyroidism in kidney disease: what we know and do not know about use of calcimimetics and vitamin D analogs. Int J Nephrol Renovasc Dis 2008; 1:5-17. [PMID: 21694914 PMCID: PMC3108756 DOI: 10.2147/ijnrd.s4368] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
There is a growing understanding of the pathophysiology of secondary hyperparathyroidism (SHPT) and a recent emergence of new agents for SHPT treatment in patients with advanced kidney disease. At the same time, appreciation that mineral metabolic derangements promote vascular calcification and contribute to excess mortality, along with recognition of potentially important “non-classical” actions of vitamin D, have prompted the nephrology community to reexamine the use of various SHPT treatments, such as activated vitamin D sterols, phosphate binders, and calcimimetics. In this review, the evidence for treatment of SHPT with calcimimetics and vitamin D analogs is evaluated, with particular consideration given to recent clinical trials that have reported encouraging findings with cinacalcet use. Additionally, several controversies in the pathogenesis and treatment of SHPT are explored. The proposition that calcitriol deficiency is a true pathological state is challenged, the relative importance of the vitamin D receptor and the calcium sensing receptor in parathyroid gland function is summarized, and the potential relevance of non-classical actions of vitamin D for patients with advanced renal disease is examined. Taken collectively, the balance of evidence now supports a treatment paradigm in which calcimimetics are the most appropriate primary treatment for SHPT in the majority of end stage renal disease patients, but which nevertheless acknowledges an important role for modest doses of activated vitamin D sterols.
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Affiliation(s)
- James B Wetmore
- Department of Medicine, Division of Nephrology, University of Kansas Medical Center, Kansas City, KS, USA
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Carrillo-Lopez N, Alvarez-Hernandez D, Gonzalez-Suarez I, Roman-Garcia P, Valdivielso JM, Fernandez-Martin JL, Cannata-Andia JB. Simultaneous changes in the calcium-sensing receptor and the vitamin D receptor under the influence of calcium and calcitriol. Nephrol Dial Transplant 2008; 23:3479-84. [DOI: 10.1093/ndt/gfn338] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Wetmore JB, Quarles LD. Calcimimetics or vitamin D analogs for suppressing parathyroid hormone in end-stage renal disease: time for a paradigm shift? ACTA ACUST UNITED AC 2008; 5:24-33. [PMID: 18957950 DOI: 10.1038/ncpneph0977] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2008] [Accepted: 09/09/2008] [Indexed: 12/14/2022]
Abstract
Considerable advances have been made in the understanding of the pathogenesis and treatment of secondary hyperparathyroidism (SHPT) in chronic kidney disease (CKD). These include the discovery that the calcium-sensing receptor has an important role in the regulation of parathyroid gland function, the development of calcimimetics to target this receptor, the recognition that vitamin D receptor activation has important functions beyond the regulation of mineral metabolism, the identification of the phosphaturic factor fibroblast growth factor 23 and the contribution of this hormone to disordered phosphate and vitamin D metabolism in CKD. However, despite the availability of calcimimetics, phosphate binders, and vitamin D analogs, control of SHPT remains suboptimal in many patients with advanced kidney disease. In this Review, we explore several unresolved issues regarding the pathogenesis and treatment of SHPT. Specifically, we examine the significance of elevated circulating fibroblast growth factor 23 levels in CKD, question the proposition that calcitriol deficiency is truly a pathological state, explore the relative importance of the vitamin D receptor and the calcium-sensing receptor in parathyroid gland function and evaluate the evidence to support the treatment of SHPT with calcimimetics and vitamin D analogs. Finally, we propose a novel treatment framework in which calcimimetics are the primary therapy for suppressing parathyroid hormone production in patients with end-stage renal disease.
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Affiliation(s)
- James B Wetmore
- Division of Nephrology and Hypertension, University of Kansas Medical Center, Kansas City, KS 66160, USA
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Tfelt-Hansen J, Brown EM. THE CALCIUM-SENSING RECEPTOR IN NORMAL PHYSIOLOGY AND PATHOPHYSIOLOGY: A Review. Crit Rev Clin Lab Sci 2008; 42:35-70. [PMID: 15697170 DOI: 10.1080/10408360590886606] [Citation(s) in RCA: 173] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The discovery of a G protein-coupled, calcium-sensing receptor (CaR) a decade ago and of diseases caused by CaR mutations provided unquestionable evidence of the CaR's critical role in the maintenance of systemic calcium homeostasis. On the cell membrane of the chief cells of the parathyroid glands, the CaR "senses" the extracellular calcium concentration and, subsequently, alters the release of parathyroid hormone (PTH). The CaR is likewise functionally expressed in bone, kidney, and gut--the three major calcium-translocating organs involved in calcium homeostasis. Intracellular signal pathways to which the CaR couples via its associated G proteins include phospholipase C (PLC), protein kinase B (AKT); and mitogen-activated protein kinases (MAPKs). The receptor is widely expressed in various tissues and regulates important cellular functions in addition to its role in maintaining systemic calcium homeostasis, i.e., protection against apoptosis, cellular proliferation, and membrane voltage. Functionally significant mutations in the receptor have been shown to induce diseases of calcium homeostasis owing to changes in the set point for calcium-regulated PTH release as well as alterations in the renal handling of calcium. Gain-of-function mutations cause hypocalcemia, whereas loss-of-function mutations produce hypercalcemia. Recent studies have shown that the latter clinical presentation can also be caused by inactivating autoantibodies directed against the CaR Newly discovered type II allosteric activators of the CaR have been found to be effective as a medical treatment for renal secondary hyperparathyroidism.
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Affiliation(s)
- Jacob Tfelt-Hansen
- Laboratory of Molecular Cardiology, Medical Department B, H:S Rigshospitalet, University of Copenhagen, Copenhagen O, Denmark.
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