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Díaz-Tocados JM, Rodríguez-Ortiz ME, Almadén Y, Pineda C, Martínez-Moreno JM, Herencia C, Vergara N, Pendón-Ruiz de Mier MV, Santamaría R, Rodelo-Haad C, Casado-Díaz A, Lorenzo V, Carvalho C, Frazão JM, Felsenfeld AJ, Richards WG, Aguilera-Tejero E, Rodríguez M, López I, Muñoz-Castañeda JR. Calcimimetics maintain bone turnover in uremic rats despite the concomitant decrease in parathyroid hormone concentration. Kidney Int 2019; 95:1064-1078. [PMID: 30878213 DOI: 10.1016/j.kint.2018.12.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 12/01/2018] [Accepted: 12/06/2018] [Indexed: 12/19/2022]
Abstract
Calcimimetics decrease parathyroid hormone (PTH) secretion in patients with secondary hyperparathyroidism. The decrease in PTH should cause a reduction in bone turnover; however, the direct effect of calcimimetics on bone cells, which express the calcium-sensing receptor (CaSR), has not been defined. In this study, we evaluated the direct bone effects of CaSR activation by a calcimimetic (AMG 641) in vitro and in vivo. To create a PTH "clamp," total parathyroidectomy was performed in rats with and without uremia induced by 5/6 nephrectomy, followed by a continuous subcutaneous infusion of PTH. Animals were then treated with either the calcimimetic or vehicle. Calcimimetic administration increased osteoblast number and osteoid volume in normal rats under a PTH clamp. In uremic rats, the elevated PTH concentration led to reduced bone volume and increased bone turnover, and calcimimetic administration decreased plasma PTH. In uremic rats exposed to PTH at 6-fold the usual replacement dose, calcimimetic administration increased osteoblast number, osteoid surface, and bone formation. A 9-fold higher dose of PTH caused an increase in bone turnover that was not altered by the administration of calcimimetic. In an osteosarcoma cell line, the calcimimetic induced Erk1/2 phosphorylation and the expression of osteoblast genes. The addition of a calcilytic resulted in the opposite effect. Moreover, the calcimimetic promoted the osteogenic differentiation and mineralization of human bone marrow mesenchymal stem cells in vitro. Thus, calcimimetic administration has a direct anabolic effect on bone that counteracts the decrease in PTH levels.
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Affiliation(s)
- Juan M Díaz-Tocados
- Maimonides Institute for Biomedical Research (IMIBIC), Cordoba, Spain; Nephrology Service, Reina Sofia University Hospital, Cordoba, Spain; University of Cordoba, Cordoba, Spain; Spanish Renal Research Network (REDinREN), Institute of Health Carlos III, Madrid, Spain
| | - María E Rodríguez-Ortiz
- Spanish Renal Research Network (REDinREN), Institute of Health Carlos III, Madrid, Spain; Laboratory of Nephrology, Health Research Institute-Jiménez Diaz Foundation, Madrid, Spain
| | - Yolanda Almadén
- Maimonides Institute for Biomedical Research (IMIBIC), Cordoba, Spain; Internal Medicine Service, Reina Sofia University Hospital, Cordoba, Spain; Spanish Biomedical Research Networking Centre Consortium for the Area of Physiopathology of Obesity and Nutrition (CIBEROBN), Institute of Health Carlos III, Madrid, Spain
| | - Carmen Pineda
- University of Cordoba, Cordoba, Spain; Department of Medicine and Animal Surgery, Cordoba, Spain
| | - Julio M Martínez-Moreno
- Maimonides Institute for Biomedical Research (IMIBIC), Cordoba, Spain; Nephrology Service, Reina Sofia University Hospital, Cordoba, Spain; University of Cordoba, Cordoba, Spain; Spanish Renal Research Network (REDinREN), Institute of Health Carlos III, Madrid, Spain
| | - Carmen Herencia
- Maimonides Institute for Biomedical Research (IMIBIC), Cordoba, Spain; Nephrology Service, Reina Sofia University Hospital, Cordoba, Spain; University of Cordoba, Cordoba, Spain; Spanish Renal Research Network (REDinREN), Institute of Health Carlos III, Madrid, Spain
| | - Noemi Vergara
- Maimonides Institute for Biomedical Research (IMIBIC), Cordoba, Spain; Nephrology Service, Reina Sofia University Hospital, Cordoba, Spain; University of Cordoba, Cordoba, Spain; Spanish Renal Research Network (REDinREN), Institute of Health Carlos III, Madrid, Spain
| | - M Victoria Pendón-Ruiz de Mier
- Maimonides Institute for Biomedical Research (IMIBIC), Cordoba, Spain; Nephrology Service, Reina Sofia University Hospital, Cordoba, Spain; University of Cordoba, Cordoba, Spain; Spanish Renal Research Network (REDinREN), Institute of Health Carlos III, Madrid, Spain
| | - Rafael Santamaría
- Maimonides Institute for Biomedical Research (IMIBIC), Cordoba, Spain; Nephrology Service, Reina Sofia University Hospital, Cordoba, Spain; University of Cordoba, Cordoba, Spain; Spanish Renal Research Network (REDinREN), Institute of Health Carlos III, Madrid, Spain
| | - Cristian Rodelo-Haad
- Maimonides Institute for Biomedical Research (IMIBIC), Cordoba, Spain; Nephrology Service, Reina Sofia University Hospital, Cordoba, Spain; University of Cordoba, Cordoba, Spain; Spanish Renal Research Network (REDinREN), Institute of Health Carlos III, Madrid, Spain
| | - Antonio Casado-Díaz
- Maimonides Institute for Biomedical Research (IMIBIC), Cordoba, Spain; University of Cordoba, Cordoba, Spain; Clinical Management Unit for Endocrinology and Nutrition, Reina Sofia University Hospital, Cordoba, Spain; Network for Cooperative Research on Aging and Fragility (RETICEF) & Spanish Biomedical Research Networking Centre Consortium for the Area of Frailty and Healthy Aging (CIBERFES), Institute of Health Carlos III, Madrid, Spain
| | - Víctor Lorenzo
- University Hospital of Tenerife, Nephrology Service, Canary Islands, Spain
| | - Catarina Carvalho
- Braga Hospital, Department of Nephrology, Braga, Portugal; Institute of Investigation and Innovation in Health (I3S), University of Porto, Porto, Portugal; National Institute of Biomedical Engineering (INEB), University of Porto, Porto, Portugal
| | - João M Frazão
- Institute of Investigation and Innovation in Health (I3S), University of Porto, Porto, Portugal; National Institute of Biomedical Engineering (INEB), University of Porto, Porto, Portugal; Department of Nephrology, São João Hospital Center, Porto, Portugal
| | - Arnold J Felsenfeld
- Department of Medicine, Veterans Affairs Greater Los Angeles Healthcare System and the David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA
| | | | | | - Mariano Rodríguez
- Maimonides Institute for Biomedical Research (IMIBIC), Cordoba, Spain; Nephrology Service, Reina Sofia University Hospital, Cordoba, Spain; University of Cordoba, Cordoba, Spain; Spanish Renal Research Network (REDinREN), Institute of Health Carlos III, Madrid, Spain.
| | - Ignacio López
- University of Cordoba, Cordoba, Spain; Department of Medicine and Animal Surgery, Cordoba, Spain
| | - Juan R Muñoz-Castañeda
- Maimonides Institute for Biomedical Research (IMIBIC), Cordoba, Spain; Nephrology Service, Reina Sofia University Hospital, Cordoba, Spain; University of Cordoba, Cordoba, Spain; Spanish Renal Research Network (REDinREN), Institute of Health Carlos III, Madrid, Spain
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2
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Harada K, Fujioka A, Konno M, Inoue A, Yamada H, Hirota Y. Pharmacology of Parsabiv ® (etelcalcetide, ONO-5163/AMG 416), a novel allosteric modulator of the calcium-sensing receptor, for secondary hyperparathyroidism in hemodialysis patients. Eur J Pharmacol 2018; 842:139-145. [PMID: 30342948 DOI: 10.1016/j.ejphar.2018.10.021] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 10/17/2018] [Accepted: 10/17/2018] [Indexed: 11/18/2022]
Abstract
Etelcalcetide hydrochloride (Parsabiv®, ONO-5163/AMG 416) is an allosteric modulator of the calcium (Ca)-sensing receptor that was originally produced by KAI Pharmaceuticals Inc. (now Amgen Inc.). It has recently been approved as the first intravenous calcimimetic agent for secondary hyperparathyroidism (SHPT) in many countries. Etelcalcetide is an intravenous injectable drug that can be administered and eliminated through the dialysis circuit in chronic kidney disease patients. In the present study, we evaluated the in vitro pharmacological profile and in vivo parathyroid hormone (PTH)- and Ca-lowering activities of etelcalcetide in a rat 5/6 nephrectomy model of chronic renal insufficiency with SHPT. Etelcalcetide increased the intracellular Ca concentration in HEK-293T cells expressing human Ca-sensing receptor with an EC50 value (95% confidence interval) of 0.53 μM (0.28-1.0 μM) and suppressed PTH secretion from rat parathyroid gland cells with 0.36 μM (0.24-0.54 μM) by activating Ca-sensing receptor. The specificity of etelcalcetide was evaluated by examining its ability to stimulate or inhibit radioligand binding to a panel of 34 off-target proteins. There were no significant changes in the presence of 10 μM etelcalcetide. Furthermore, in a rat 5/6 nephrectomy model of chronic renal insufficiency with SHPT, single intravenous administration of etelcalcetide at 0.3, 1.0, and 3.0 mg/kg decreased plasma PTH and serum Ca levels. Taken together, the present findings identify etelcalcetide as a calcimimetic with potent PTH- and Ca-lowering effects via Ca-sensing receptor agonist activity.
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Affiliation(s)
- Kazutsune Harada
- Discovery Research Laboratories, Ono Pharmaceutical Co., Ltd., 3-1-1 Sakurai, Shimamoto-cho, Mishima-gun, Osaka 618-8585, Japan
| | - Aiko Fujioka
- Discovery Research Laboratories, Ono Pharmaceutical Co., Ltd., 3-1-1 Sakurai, Shimamoto-cho, Mishima-gun, Osaka 618-8585, Japan.
| | - Masakazu Konno
- International Business Corporate Development & Strategy, Ono Pharmaceutical Co., Ltd., 3-1-1 Sakurai, Shimamoto-cho, Mishima-gun, Osaka 618-8585, Japan
| | - Atsuto Inoue
- Research Project Management Division, Ono Pharmaceutical Co., Ltd., 3-1-1 Sakurai, Shimamoto-cho, Mishima-gun, Osaka 618-8585, Japan
| | - Hiroyuki Yamada
- Discovery Research Laboratories, Ono Pharmaceutical Co., Ltd., 3-1-1 Sakurai, Shimamoto-cho, Mishima-gun, Osaka 618-8585, Japan
| | - Yasushi Hirota
- Research Project Management Division, Ono Pharmaceutical Co., Ltd., 3-1-1 Sakurai, Shimamoto-cho, Mishima-gun, Osaka 618-8585, Japan
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Li X, Yu L, Asuncion F, Grisanti M, Alexander S, Hensley K, Han CY, Niu QT, Dwyer D, Villasenor K, Stolina M, Dean C, Ominsky MS, Ke HZ, Tomlinson JE, Richards WG. Etelcalcetide (AMG 416), a peptide agonist of the calcium-sensing receptor, preserved cortical bone structure and bone strength in subtotal nephrectomized rats with established secondary hyperparathyroidism. Bone 2017; 105:163-172. [PMID: 28867373 DOI: 10.1016/j.bone.2017.08.026] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 08/24/2017] [Accepted: 08/28/2017] [Indexed: 10/18/2022]
Abstract
Sustained elevation of parathyroid hormone (PTH) is catabolic to cortical bone, as evidenced by deterioration in bone structure (cortical porosity), and is a major factor for increased fracture risk in chronic kidney disease (CKD). Etelcalcetide (AMG 416), a novel peptide agonist of the calcium-sensing receptor, reduces PTH levels in subtotal nephrectomized (Nx) rats and in hemodialysis patients with secondary hyperparathyroidism (SHPT) in clinical studies; however, effects of etelcalcetide on bone have not been determined. In a rat model of established SHPT with renal osteodystrophy, etelcalcetide or vehicle was administered by subcutaneous (s.c.) injection to subtotal Nx rats with elevated PTH (>750pg/mL) once per day for 6weeks. Sham-operated rats receiving vehicle (s.c.) served as non-SHPT controls. Prior to treatment, significant increases in serum creatinine (2-fold), blood urea nitrogen (BUN, 3-fold), PTH (5-fold), fibroblast growth factor-23 (FGF23; 13-fold) and osteocalcin (12-fold) were observed in SHPT rats compared to non-SHPT controls. Elevations in serum creatinine and BUN were unaffected by treatment with vehicle or etelcalcetide. In contrast, etelcalcetide significantly decreased PTH, FGF23 and osteocalcin, whereas vehicle treatment did not. Cortical bone porosity increased and bone strength decreased in vehicle-treated SHPT rats compared to non-SHPT controls. Cortical bone structure improved and energy to failure was significantly greater in SHPT rats treated with etelcalcetide compared to vehicle. Mineralization lag time and marrow fibrosis were significantly reduced by etelcalcetide. In conclusion, etelcalcetide reduced bone turnover, attenuated mineralization defect and marrow fibrosis, and preserved cortical bone structure and bone strength by lowering PTH in subtotal Nx rats with established SHPT.
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Affiliation(s)
- Xiaodong Li
- Department of Cardiometabolic Disorders, Amgen Inc., Thousand Oaks, CA, USA.
| | - Longchuan Yu
- Department of Cardiometabolic Disorders, Amgen Inc., Thousand Oaks, CA, USA
| | - Frank Asuncion
- Department of Cardiometabolic Disorders, Amgen Inc., Thousand Oaks, CA, USA
| | - Mario Grisanti
- Department of Cardiometabolic Disorders, Amgen Inc., Thousand Oaks, CA, USA
| | - Shawn Alexander
- Department of Cardiometabolic Disorders, Amgen Inc., Thousand Oaks, CA, USA
| | - Kelly Hensley
- Department of Comparative Biology and Safety Sciences, Amgen Inc., Thousand Oaks, CA, USA
| | - Chun-Ya Han
- Department of Cardiometabolic Disorders, Amgen Inc., Thousand Oaks, CA, USA
| | - Qing-Tian Niu
- Department of Cardiometabolic Disorders, Amgen Inc., Thousand Oaks, CA, USA
| | - Denise Dwyer
- Department of Cardiometabolic Disorders, Amgen Inc., Thousand Oaks, CA, USA
| | - Kelly Villasenor
- Department of Cardiometabolic Disorders, Amgen Inc., Thousand Oaks, CA, USA
| | - Marina Stolina
- Department of Cardiometabolic Disorders, Amgen Inc., Thousand Oaks, CA, USA
| | - Charles Dean
- Department of Comparative Biology and Safety Sciences, Amgen Inc., Thousand Oaks, CA, USA
| | - Michael S Ominsky
- Department of Cardiometabolic Disorders, Amgen Inc., Thousand Oaks, CA, USA
| | - Hua Zhu Ke
- Department of Cardiometabolic Disorders, Amgen Inc., Thousand Oaks, CA, USA
| | - James E Tomlinson
- Department of Cardiometabolic Disorders, Amgen Inc., Thousand Oaks, CA, USA
| | - William G Richards
- Department of Cardiometabolic Disorders, Amgen Inc., Thousand Oaks, CA, USA
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4
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Affiliation(s)
- Hirotaka Komaba
- Division of Nephrology, Endocrinology and Metabolism; Tokai University School of Medicine; Isehara Japan
| | - Masafumi Fukagawa
- Division of Nephrology, Endocrinology and Metabolism; Tokai University School of Medicine; Isehara Japan
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Massy ZA, Hénaut L, Larsson TE, Vervloet MG. Calcium-sensing receptor activation in chronic kidney disease: effects beyond parathyroid hormone control. Semin Nephrol 2015; 34:648-59. [PMID: 25498383 DOI: 10.1016/j.semnephrol.2014.10.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Secondary hyperparathyroidism (SHPT) is an important complication of advanced chronic kidney disease (CKD). Cinacalcet, an allosteric modulator of the calcium-sensing receptor (CaSR) expressed in parathyroid glands, is the only calcimimetic approved to treat SHPT in patients on dialysis. By enhancing CaSR sensitivity for plasma extracellular calcium (Ca(2+)0), cinacalcet reduces serum parathyroid hormone, Ca(2+)0, and serum inorganic phosphorous concentrations, allowing better control of SHPT and CKD-mineral and bone disorders. Of interest, the CaSR also is expressed in a variety of tissues where its activation regulates diverse cellular processes, including secretion, apoptosis, and proliferation. Thus, the existence of potential off-target effects of cinacalcet cannot be neglected. This review summarizes our current knowledge concerning the potential role(s) of the CaSR expressed in various tissues in CKD-related disorders, independently of parathyroid hormone control.
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Affiliation(s)
- Ziad A Massy
- Inserm U-1088, University of Picardie Jules Verne, Amiens, France; Division of Nephrology, Ambroise Paré Hospital, Paris-Ile-de-France-Ouest University (University of Versailles Saint-Quentin-En-Yvelines), Paris-Boulogne Billancourt, France.
| | - Lucie Hénaut
- Inserm U-1088, University of Picardie Jules Verne, Amiens, France
| | - Tobias E Larsson
- Department of Clinical Science, Intervention and Technology, Renal Unit, Karolinska Institutet, Stockholm, Sweden; Department of Nephrology, Karolinska University Hospital, Stockholm, Sweden
| | - Marc G Vervloet
- Department of Nephrology and Institute of Cardiovascular Research VU (Institute for Cardiovascular Research of the Vrije Universiteit of Amsterdam), VU University Medical Center, Amsterdam, The Netherlands
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Moe SM, Abdalla S, Chertow GM, Parfrey PS, Block GA, Correa-Rotter R, Floege J, Herzog CA, London GM, Mahaffey KW, Wheeler DC, Dehmel B, Goodman WG, Drüeke TB. Effects of Cinacalcet on Fracture Events in Patients Receiving Hemodialysis: The EVOLVE Trial. J Am Soc Nephrol 2015; 26:1466-75. [PMID: 25505257 PMCID: PMC4446874 DOI: 10.1681/asn.2014040414] [Citation(s) in RCA: 130] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 09/07/2014] [Indexed: 11/03/2022] Open
Abstract
Fractures are frequent in patients receiving hemodialysis. We tested the hypothesis that cinacalcet would reduce the rate of clinical fractures in patients receiving hemodialysis using data from the Evaluation of Cinacalcet HCl Therapy to Lower Cardiovascular Events trial, a placebo-controlled trial that randomized 3883 hemodialysis patients with secondary hyperparathyroidism to receive cinacalcet or placebo for ≤64 months. This study was a prespecified secondary analysis of the trial whose primary end point was all-cause mortality and non-fatal cardiovascular events, and one of the secondary end points was first clinical fracture event. Clinical fractures were observed in 255 of 1935 (13.2%) patients randomized to placebo and 238 of 1948 (12.2%) patients randomized to cinacalcet. In an unadjusted intention-to-treat analysis, the relative hazard for fracture (cinacalcet versus placebo) was 0.89 (95% confidence interval [95% CI], 0.75 to 1.07). After adjustment for baseline characteristics and multiple fractures, the relative hazard was 0.83 (95% CI, 0.72 to 0.98). Using a prespecified lag-censoring analysis (a measure of actual drug exposure), the relative hazard for fracture was 0.72 (95% CI, 0.58 to 0.90). When participants were censored at the time of cointerventions (parathyroidectomy, transplant, or provision of commercial cinacalcet), the relative hazard was 0.71 (95% CI, 0.58 to 0.87). Fracture rates were higher in older compared with younger patients and the effect of cinacalcet appeared more pronounced in older patients. In conclusion, using an unadjusted intention-to-treat analysis, cinacalcet did not reduce the rate of clinical fracture. However, when accounting for differences in baseline characteristics, multiple fractures, and/or events prompting discontinuation of study drug, cinacalcet reduced the rate of clinical fracture by 16%-29%.
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Affiliation(s)
- Sharon M Moe
- Indiana University School of Medicine and Roudebush Veterans Administration Medical Center, Indianapolis, Indiana;
| | - Safa Abdalla
- Stanford University School of Medicine, Palo Alto, California
| | - Glenn M Chertow
- Stanford University School of Medicine, Palo Alto, California
| | | | | | - Ricardo Correa-Rotter
- Salvador Zubirán National Institute of Medical Sciences and Nutrition, Mexico City, Mexico
| | | | | | | | | | | | | | | | - Tilman B Drüeke
- French Institute of Health and Medical Research (INSERM) Unit 1088, Faculty of Medicine/Pharmacy, University of Picardie, Amiens, France
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Abstract
The extracellular calcium-sensing receptor, CaSR, is a member of the G protein-coupled receptor superfamily and has a critical role in modulating Ca(2+) homeostasis via its role in the parathyroid glands and kidneys. New evidence suggests that CaSR expression in cartilage and bone also directly regulates skeletal homeostasis. This Review discusses the role of CaSR in chondrocytes, through which CaSR contributes to the development of the cartilaginous growth plate, as well as in osteoblasts and osteoclasts, through which CaSR has effects on skeletal development and bone turnover in young and mature animals. The interaction of skeletal CaSR activation with parathyroid hormone (PTH), which is secreted by the parathyroid gland, can lead to net bone formation in trabecular bone or net bone resorption in cortical bone. Allosteric modulators of CaSR are beneficial in some clinical conditions, with effects that are mediated by the ability of these agents to alter levels of PTH and improve Ca(2+) homeostasis. However, further insights into the action of CaSR in bone cells might lead to CaSR-based drugs that maximize not only the effects of the receptor on the parathyroid glands and kidneys but also on bone.
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Affiliation(s)
- David Goltzman
- Department of Medicine, McGill University, 687 Pine Avenue West, Montreal, QC H3A 1A1, Canada
| | - Geoffrey N Hendy
- Department of Medicine, McGill University, 687 Pine Avenue West, Montreal, QC H3A 1A1, Canada
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Rodríguez M, Goodman WG, Liakopoulos V, Messa P, Wiecek A, Cunningham J. The Use of Calcimimetics for the Treatment of Secondary Hyperparathyroidism: A 10 Year Evidence Review. Semin Dial 2015; 28:497-507. [DOI: 10.1111/sdi.12357] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Mariano Rodríguez
- Servicio de Nefrologia; IMIBIC; Hospital Universitario Reina Sofia; Córdoba Spain
| | | | - Vassilios Liakopoulos
- Division of Nephrology and Hypertension; 1st Department of Internal Medicine; Medical School; Aristotle University of Thessaloniki; Thessaloniki Greece
| | - Piergiorgio Messa
- Division of Nephrology and Dialysis; Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico; Università di Milano; Milan Italy
| | - Andrzej Wiecek
- Department of Nephrology, Endocrinology and Metabolic Diseases; Medical University of Silesia; Katowice Poland
| | - John Cunningham
- Centre for Nephrology; UCL Medical School; Royal Free Campus; London United Kingdom
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Shobeiri N, Adams MA, Holden RM. Phosphate: an old bone molecule but new cardiovascular risk factor. Br J Clin Pharmacol 2014; 77:39-54. [PMID: 23506202 PMCID: PMC3895346 DOI: 10.1111/bcp.12117] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Accepted: 02/21/2013] [Indexed: 12/24/2022] Open
Abstract
Phosphate handling in the body is complex and involves hormones produced by the bone, the parathyroid gland and the kidneys. Phosphate is mostly found in hydroxyapatite. however recent evidence suggests that phosphate is also a signalling molecule associated with bone formation. Phosphate balance requires careful regulation of gut and kidney phosphate transporters, SLC34 transporter family, but phosphate signalling in osteoblasts and vascular smooth muscle cells is likely mediated by the SLC20 transporter family (PiT1 and PiT2). If not properly regulated, phosphate imblanace could lead to mineral disorders as well as vascular calcification. In chronic kidney disease-mineral bone disorder, hyperphosphataemia has been consistently associated with extra-osseous calcification and cardiovascular disease. This review focuses on the physiological mechanisms involved in phosphate balance and cell signalling (i.e. osteoblasts and vascular smooth muscle cells) as well as pathological consequences of hyperphosphataemia. Finally, conventional as well as new and experimental therapeutics in the treatment of hyperphosphataemia are explored.
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Affiliation(s)
- Navid Shobeiri
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
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Nakayama K, Nakao K, Takatori Y, Inoue J, Kojo S, Akagi S, Fukushima M, Wada J, Makino H. Long-term effect of cinacalcet hydrochloride on abdominal aortic calcification in patients on hemodialysis with secondary hyperparathyroidism. Int J Nephrol Renovasc Dis 2013; 7:25-33. [PMID: 24379691 PMCID: PMC3872220 DOI: 10.2147/ijnrd.s54731] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Background Secondary hyperparathyroidism (SHPT) is one of the common complications in dialysis patients, and is associated with increased risk of vascular calcification. The effects of cinacalcet hydrochloride treatment on bone and mineral metabolism have been previously reported, but the benefit of cinacalcet on vascular calcification remains uncertain. The aim of this study was to evaluate the impact of cinacalcet on abdominal aortic calcification in dialysis patients. Subjects and methods Patients were on maintenance hemodialysis with insufficiently controlled SHPT (intact parathyroid hormone [PTH] >180 pg/mL) by conventional therapies. All subjects were initially administered 25 mg cinacalcet daily, with concomitant use of calcitriol analogs. Abdominal aortic calcification was annually evaluated by calculating aortic calcification area index (ACAI) using multidetector computed tomography (MDCT), from 12 months before to 36 months after the initiation of cinacalcet therapy. Results Twenty-three patients were analyzed in this study. The mean age was 59.0±8.7 years, 34.8% were women, and the mean dialysis duration was 163.0±76.0 months. After administration of cinacalcet, serum levels of intact PTH, phosphorus, and calcium significantly decreased, and mean Ca × P values significantly decreased from 67.4±7.9 mg2/dL2 to 52±7.7 mg2/dL2. Although the ACAI value did not decrease during the observation period, the increase in ACAI between 24 months and 36 months after cinacalcet administration was significantly suppressed. Conclusion Long-term administration of cinacalcet was associated with reduced progression of abdominal aortic calcification, and achieving appropriate calcium and phosphorus levels may reduce the rates of cardiovascular events and mortality in patients on hemodialysis.
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Affiliation(s)
- Kazunori Nakayama
- Department of Medicine and Clinical Science, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan ; Shigei Medical Research Hospital, Okayama, Japan
| | - Kazushi Nakao
- Department of Medicine and Clinical Science, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan ; Shigei Medical Research Hospital, Okayama, Japan
| | - Yuji Takatori
- Department of Medicine and Clinical Science, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan ; Shigei Medical Research Hospital, Okayama, Japan
| | - Junko Inoue
- Department of Medicine and Clinical Science, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Shoichirou Kojo
- Department of Medicine and Clinical Science, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Shigeru Akagi
- Department of Medicine and Clinical Science, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan ; Shigei Medical Research Hospital, Okayama, Japan
| | | | - Jun Wada
- Department of Medicine and Clinical Science, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Hirofumi Makino
- Department of Medicine and Clinical Science, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
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11
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Imanishi Y, Inaba M, Kawata T, Nishizawa Y. Animal models of hyperfunctioning parathyroid diseases for drug development. Expert Opin Drug Discov 2013; 4:727-40. [PMID: 23489166 DOI: 10.1517/17460440903022743] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Disorders of mineral and bone metabolism have been implicated as a risk factor in the high mortality in patients with chronic kidney disease (CKD). Hyperphosphatemia, disorders of vitamin D metabolism and secondary hyperparathyroidism of uremia (SHPT) are therapeutic targets in these patients to improve the mortality. Animal models for CKD are indispensable and uremic rats produced by 5/6-nephrectomies are one of the most useful animal models for the development of new therapeutic agents. As there are limitations of uremic rats such as short lifespan and less severity of secondary hyperparathyroidism distinct from CKD patients on maintenance hemodialysis, the development of new model animals is expected. OBJECTIVE This review discusses the molecular pathogenesis of hyperfunctioning parathyroid diseases and the applications of animal models exhibiting hyperparathyroidisms in the aspect of the development of new therapeutics. CONCLUSION PTH-cyclin D1 transgenic mice, with parathyroid-targeted overexpression of cyclin D1 oncogene, not only developed abnormal parathyroid cell proliferation but, notably, also developed biochemical hyperparathyroidism with characteristic abnormalities in bone. The mice exhibit age-dependent development of biochemical hyperparathyroidism, which enables testing of the drug precisely. In addition, the mice develop parathyroid cell hyperplasia, followed by monoclonal expansion, which is observed in refractory SHPT patients.
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Affiliation(s)
- Yasuo Imanishi
- Osaka City University Graduate School of Medicine, Metabolism, Endocrinology and Molecular Medicine, 1-4-3, Asahi-machi, Abeno-ku, Osaka 545 8585, Japan +81 6 6645 3806 ; +81 6 6645 3808 ;
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12
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Abstract
Parathyroid hormone (PTH) is a uremic toxin with multiple systemic effects including bone disorders (renal osteodystrophy), myopathy, neurologic abnormalities, anemia, pruritus, and cardiomyopathy. Hyperparathyroidism is common in CKD and results in significant morbidity and mortality if left untreated. Clinical practice guidelines from the Kidney Disease Improving Global Outcomes initiative broadened the optimal PTH range to >2 and <9 times the upper limit of normal for the assay measured. Furthermore, the guidelines recommend following trends in PTH to determine the appropriate therapy. These guidelines overcome issues with the assay variability and help clinicians make judgments when treating individual patients. They also require frequent measurement in order to determine trends and implement appropriate treatments.
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Affiliation(s)
- Stuart M Sprague
- Division of Nephrology and Hypertension, NorthShore University HealthSystem, Evanston, IL 60201, USA.
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Zhang Q, Li M, You L, Li H, Ni L, Gu Y, Hao C, Chen J. Effects and safety of calcimimetics in end stage renal disease patients with secondary hyperparathyroidism: a meta-analysis. PLoS One 2012; 7:e48070. [PMID: 23133549 PMCID: PMC3485048 DOI: 10.1371/journal.pone.0048070] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2012] [Accepted: 09/20/2012] [Indexed: 11/19/2022] Open
Abstract
Purpose Secondary hyperparathyroidism (SHPT) is one of the most common abnormalities of mineral metabolism in patients with chronic kidney disease. We performed a meta-analysis to determine the effect and safety of cinacalcet in SHPT patients receiving dialysis. Methods The meta-analysis was performed to determine the effect and safety of cinacalcet in SHPT patients receiving dialysis by using the search terms ‘cinacalcet’ or ‘mimpara’ or ‘sensipar’ or ‘calcimimetic’ or ‘R586’ on MEDLINE and EMBASE (January 1990 to February 2012). Results Fifteen trials were included, all of which were performed between 2000 and 2011 enrolling a total of 3387 dialysis patients. Our study showed that calcimimetic agents effectively ameliorated iPTH levels(WMD, −294.36 pg/mL; 95% CI, −322.76 to −265.95, P<0.001) in SHPT patients and reduced serum calcium (WMD, −0.81 mg/dL; 95% CI, −0.89 to −0.72, P<0.001) and phosphorus disturbances(WMD, −0.29 mg/dL; 95% CI, −0.41 to −0.17, P<0.001). The percentage of patients in whom there was a 30% decrease in serum iPTH levels by the end of the dosing was higher in cinacalcet group than that in control group(OR = 10.75, 95% CI: 6.65–17.37, P<0.001). However, no significant difference was found in all-cause mortality and all adverse events between calcimimetics and control groups(OR = 0.86, 95% CI: 0.46–1.60, P = 0.630; OR = 1.30, 95% CI: 0.78–2.18, P = 0.320, respectively). Compared with the control therapy, there was a significant increase in the episodes of hypocalcemia (OR = 2.46, 95% CI: 1.58–3.82, P<0.001), nausea (OR = 2.45, 95% CI: 1.29–4.66, P = 0.006), vomiting(OR = 2.78, 95% CI: 2.14–3.62, P<0.001), diarrhea(OR = 1.51, 95% CI: 1.04–2.20, P = 0.030) and upper respiratory tract infection (OR = 1.79, 95% CI: 1.20–2.66, P = 0.004)in calcimimetics group. Conclusions Calcimimetic treatment effectively improved biochemical parameters of SHPT patients receiving dialysis without increasing all-cause mortality and all adverse events.
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Affiliation(s)
- Qian Zhang
- Division of Nephrology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Ming Li
- Department of Respiratory Medicine, Shanghai Tenth People’s Hospital Affiliated to Tongji University, Shanghai, China
| | - Li You
- Division of Nephrology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Haiming Li
- Division of Nephrology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Li Ni
- Division of Nephrology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Yong Gu
- Division of Nephrology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Chuanming Hao
- Division of Nephrology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
- Division of Nephrology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Jing Chen
- Division of Nephrology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
- * E-mail:
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Tsuruta Y, Okano K, Kikuchi K, Tsuruta Y, Akiba T, Nitta K. Effects of cinacalcet on bone mineral density and bone markers in hemodialysis patients with secondary hyperparathyroidism. Clin Exp Nephrol 2012; 17:120-6. [DOI: 10.1007/s10157-012-0665-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2011] [Accepted: 06/22/2012] [Indexed: 11/29/2022]
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15
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Chertow GM, Correa-Rotter R, Block GA, Drueke TB, Floege J, Goodman WG, Herzog CA, Kubo Y, London GM, Mahaffey KW, Mix TC, Moe SM, Wheeler DC, Parfrey PS. Baseline characteristics of subjects enrolled in the Evaluation of Cinacalcet HCl Therapy to Lower Cardiovascular Events (EVOLVE) trial. Nephrol Dial Transplant 2012; 27:2872-9. [PMID: 22529163 DOI: 10.1093/ndt/gfr777] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Secondary hyperparathyroidism (sHPT) and other abnormalities associated with chronic kidney disease-mineral bone disorder can contribute to dystrophic (including vascular) calcification. Dietary modification and variety of medications can be used to attenuate the severity of sHPT. However, it is unknown whether any of these approaches can reduce the high risks of death and cardiovascular disease in patients with end-stage renal disease. METHODS The Evaluation of Cinacalcet HCl Therapy to Lower Cardiovascular Events (EVOLVE) trial was designed to test the hypothesis that treatment with the calcimimetic agent cinacalcet compared with placebo (on a background of conventional therapy including phosphate binders +/- vitamin D sterols) reduces time to death or non-fatal cardiovascular events (specifically myocardial infarction, unstable angina, heart failure and peripheral arterial disease events) among patients on hemodialysis with sHPT. This report describes baseline characteristics of enrolled subjects with a focus on regional variation. RESULTS There were 3883 subjects randomized from 22 countries, including the USA, Canada, Australia, three Latin American nations, Russia and 15 European nations. The burden of overt cardiovascular disease at baseline was high (e.g. myocardial infarction 12.4%, heart failure 23.3%). The median plasma parathyroid hormone concentration at baseline was 692 pg/mL (10%, 90% range, 363-1694 pg/mL). At baseline, 87.2% of subjects were prescribed phosphate binders and 57.5% were prescribed activated vitamin D derivatives. Demographic data, comorbid conditions and baseline laboratory data varied significantly across regions. CONCLUSIONS EVOLVE enrolled 3883 subjects on hemodialysis with moderate to severe sHPT. Inclusion of subjects from multiple global regions with varying degrees of disease severity will enhance the external validity of the trial results.
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Moe SM, Radcliffe JS, White KE, Gattone VH, Seifert MF, Chen X, Aldridge B, Chen NX. The pathophysiology of early-stage chronic kidney disease-mineral bone disorder (CKD-MBD) and response to phosphate binders in the rat. J Bone Miner Res 2011; 26:2672-81. [PMID: 21826734 DOI: 10.1002/jbmr.485] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Chronic kidney disease-mineral bone disorder (CKD-MBD) is a systemic disorder that describes the complex bone and mineral abnormalities that occur in CKD. To understand the pathophysiology of CKD-MBD and determine whether the early use of phosphate binders would alter this physiology, we used a naturally occurring, slowly progressive model of CKD-MBD, the Cy/+ rat. Male Cy/+ rats were compared with their normal littermates at 20 weeks of age after 1 week of no phosphate binder, calcium carbonate, or sevelamer carbonate. The Cy/+ rat had renal function that was 50% of that of normal littermates, elevated parathyroid hormone (PTH) and fibroblast growth factor 23 (FGF23), decreased 1,25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)] levels, but normal calcium and phosphorus levels. There was a significant positive correlation of blood FGF23 and phosphorus levels and blood FGF23 and urine phosphorus levels. There was an inverse correlation between FGF23 and calcium levels. mRNA from the kidney demonstrated 50% reduction in klotho and Npt2a expression but no difference in CYP27B1. In the intestine, CKD animals had reduced active phosphate absorption in the jejunum using modified Ussing chambers and a reduction in Npt2b expression throughout the small intestine compared with normal littermates. In bone, mRNA expression of FGF23 was reduced (driven by lowering with phosphate binders), and TRAP expression was increased in CKD. By histology, there was increased osteoclast activity and number, and there were reductions in some measures of femoral neck mechanical strength. One week of phosphate binders reduced intestinal phosphate flux, serum phosphorus levels, and urinary phosphate excretion. These results demonstrate marked abnormalities in kidney, intestine, and bone in early CKD-MBD. While phosphate binders were effective in lowering urine phosphorus, they had little effect on end organs after 1 week of administration.
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Affiliation(s)
- Sharon M Moe
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
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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: 350] [Impact Index Per Article: 26.9] [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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Abstract
Accelerated atherosclerotic plaque calcification and extensive medial calcifications are common and highly detrimental complications of chronic kidney disease. Valid murine models have been developed to investigate both pathologically distinguishable complications, which allow for better insight into the cellular mechanisms underlying these vascular pathologies and evaluation of compounds that might prevent or retard the onset or progression of vascular calcification. This review describes various experimental models that have been used for the study of arterial intimal and/or medial calcification and discusses the extent to which this experimental research has contributed to our current understanding of vascular calcification, particularly in the setting of chronic renal failure.
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Affiliation(s)
- Ellen Neven
- From the Department of Pathophysiology, University of Antwerp, Antwerp, Belgium
| | - Patrick C. D'Haese
- From the Department of Pathophysiology, University of Antwerp, Antwerp, Belgium
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Banerjee S, Smith B, Hitchcock SR. A dimethylzinc/diphenylphosphinoylimine approach to the asymmetric synthesis of the calcimimetic agent NPS R-568. Appl Organomet Chem 2010. [DOI: 10.1002/aoc.1723] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Affiliation(s)
- David Goltzman
- Departments of Medicine and Physiology, McGill University and McGill University Health Centre, Montreal, Canada
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22
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Brown EM. Clinical utility of calcimimetics targeting the extracellular calcium-sensing receptor (CaSR). Biochem Pharmacol 2010; 80:297-307. [PMID: 20382129 DOI: 10.1016/j.bcp.2010.04.002] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Revised: 03/31/2010] [Accepted: 04/01/2010] [Indexed: 02/03/2023]
Abstract
Calcimimetics, which activate the extracellular calcium (Ca(o)(2+))-sensing receptor in the parathyroid and other tissues participating in Ca(o)(2+) homeostasis, were the first described allosteric activators of a G-protein-coupled receptor. Cinacalcet, the only calcimimetic currently approved for human use, is used clinically for treating secondary hyperparathyroidism (e.g., overactivity of parathyroid glands) in patients being dialyzed for chronic kidney disease. By sensitizing the parathyroids to Ca(o)(2+), cinacalcet lowers the circulating parathyroid hormone (PTH) level. It also reduces serum calcium and phosphate, changes increasing the percentage of patients achieving the guidelines recommended by the National Kidney Foundation (NKF) for these minerals. Studies are underway addressing whether better adherence to these guidelines in patients receiving cinacalcet reduces cardiovascular disease and related mortality, which are both common is the dialysis population. The second approved use of cinacalcet is for treating hypercalcemia in patients with inoperable parathyroid carcinoma. In this setting, it provides the first medical therapy chronically lowering serum calcium concentration in this condition, albeit not to normal in most patients. Its effect on the long-term prognosis of these patients, if any, is presently unclear. "Off-label" administration of cinacalcet [i.e., not yet approved by the US Food and Drug Administration (FDA)] effectively lowers serum calcium and/or PTH in various other forms of hyperparathyroidism and increases serum phosphate in renal phosphate-wasting syndromes by reducing PTH-induced phosphaturia. In the future, the drug could conceivably be utilized to modulate the activity of the CaSR in other tissues (i.e., kidney, colon) in therapeutically desirable ways.
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Affiliation(s)
- Edward M Brown
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, EBRC 223A, 221 Longwood Ave, Boston, MA 02115, United States.
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Morales E, Gutierrez E, Andres A. Treatment with calcimimetics in kidney transplantation. Transplant Rev (Orlando) 2010; 24:79-88. [DOI: 10.1016/j.trre.2010.01.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2009] [Accepted: 01/18/2010] [Indexed: 11/26/2022]
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Imanishi Y, Inaba M, Kawata T, Nishizawa Y. Cinacalcet in Hyperfunctioning Parathyroid Diseases. Ther Apher Dial 2009; 13 Suppl 1:S7-S11. [DOI: 10.1111/j.1744-9987.2009.00768.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Abstract
Currently available cinacalcet hydrochloride has a greater advantage over conventional vitamin D therapy, although the ability of cinacalcet to suppress parathyroid hormone (PTH) varies among individuals. This article deals with the clinical issues of cinacalcet. Studies examining the impact of cinacalcet on parathyroid gland cells showed that cinacalcet may cause changes in PTH secretion, reduce the parathyroid gland size, and alter parathyroid gland function, suggesting the possibility that use of cinacalcet can eventually be stopped. Combined cinacalcet and vitamin D can reportedly increase vitamin D receptor expression. In a double-blind, placebo-controlled randomized study involving 1184 previously untreated secondary hyperparathyroidism (SHPT) patients, cinacalcet significantly reduced the likelihood of hospitalization for parathyroidectomy, fractures, and cardiovascular disease. Fibrous osteitis was suppressed in the rat model of renal failure treated with cinacalcet. Considering that the drug price of cinacalcet is lower in Japan than in the USA and Europe, it is highly likely that cinacalcet will be used to suppress PTH in Japan.
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Affiliation(s)
- Keitaro Yokoyama
- Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, 3-25-8 Nishi-Shinbashi, Minato-ku, Tokyo 105-8471, Japan.
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Yokoyama K. Cinacalcet Hydrochloride in Chronic Kidney Disease–Mineral Bone Disorder: Table 1. Clin J Am Soc Nephrol 2009; 4:1405-8. [DOI: 10.2215/cjn.05030709] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Bover J, Aguilar A, Baas J, Reyes J, Lloret MJ, Farré N, Olaya M, Canal C, Marco H, Andrés E, Trinidad P, Ballarin J. Calcimimetics in the chronic kidney disease-mineral and bone disorder. Int J Artif Organs 2009; 32:108-21. [PMID: 19363783 DOI: 10.1177/039139880903200208] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Mineral and bone disorders (MBD) are both an early and very common complication of chronic kidney disease (CKD). It is now accepted that they represent a significant risk factor, explaining the high cardiovascular morbidity and mortality in CKD patients. During the last decade, we have been witnessing many advances in the nomenclature, classification, pathophysiology, diagnosis, and treatment of CKD and some of its complications, such as CKD-MBD. The identification of the calcium-sensing receptor (CaSR) involvement in the pathogenesis of primary and secondary hyperparathyroidism (SHPT) and the availability of a new class of drugs called calcimimetics are two outstanding examples. Cinacalcet, the only available calcimimetic, has been shown to be a very effective therapeutic tool in CKD-MBD. Many clinical trials with cinacalcet in hemodialysis patients with SHPT have shown a reduction in parathyroid hormone, calcium (Ca), phosphate (P) and Ca x P product levels, allowing far greater success in reaching therapeutic goals as recommended by international guidelines. Additionally, some studies have shown that the use of cinacalcet may improve other aspects of CKD-MBD, reducing the risk of vascular calcification and parathyroidectomy, among others. Prospective studies on dialysis patients, with hard endpoint data, are currently underway. This review summarizes the most significant aspects of calcimimimetics based on both experimental and clinical results, underlining their possibilities not only for the treatment of isolated SHPT but also for other CKD-MBD related conditions.
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Affiliation(s)
- Jordi Bover
- Fundació Puigvert, Universitat Autònoma de Barcelona, Catalonia. REDinREN, Instituto de Investigación Carlos III - Spain.
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The calcimimetic AMG 641 abrogates parathyroid hyperplasia, bone and vascular calcification abnormalities in uremic rats. Eur J Pharmacol 2009; 616:306-13. [PMID: 19470383 DOI: 10.1016/j.ejphar.2009.05.013] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2008] [Revised: 04/27/2009] [Accepted: 05/14/2009] [Indexed: 11/21/2022]
Abstract
Calcimimetics and vitamin D sterols reduce serum parathyroid hormone (PTH) in patients with secondary hyperparathyroidism receiving dialysis, a disease state associated with parathyroid hyperplasia, vascular calcification, bone disease, and increased mortality. The aim of this study was to determine the effects of the research calcimimetic AMG 641 (Amgen, Inc., Thousand Oaks, CA) or calcitriol (Sigma Aldrich Corporation, St. Louis, MO) on vascular calcification in a rodent model of progressive uremia with accompanying secondary hyperparathyroidism induced by dietary adenine. Treatment effects on parathyroid gland hyperplasia and bone loss were also investigated. Rats were treated daily with vehicle, calcitriol (10 ng), AMG 641 (3 mg/kg), or no treatment during the 4 week period the animals were fed adenine. The uremia-induced increases in serum PTH levels were significantly attenuated by both AMG 641 (>90%) and calcitriol (approximately 50%). AMG 641 significantly reduced calcium-phosphorus product (CaxP) and significantly attenuated the development of both parathyroid hyperplasia and vascular calcification. In addition, AMG 641 prevented the defects in trabecular bone volume, trabecular number, and bone mineralization, as well as increases in trabecular spacing in this rodent model of secondary hyperparathyroidism. Calcitriol (10 ng/rat) decreased osteoid surface/bone surface, but had no effects on other bone parameters, or parathyroid hyperplasia (likely due to the lower PTH suppressive effect of calcitriol at the dose used in this study). However, this dose of calcitriol significantly exacerbated vascular calcification. These results suggest that calcimimetics can reduce the development of vascular calcification, parathyroid hyperplasia and bone abnormalities associated with secondary hyperparathyroidism.
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Moe SM, Seifert MF, Chen NX, Sinders RM, Chen X, Duan D, Henley C, Martin D, Gattone VH. R-568 reduces ectopic calcification in a rat model of chronic kidney disease-mineral bone disorder (CKD-MBD). Nephrol Dial Transplant 2009; 24:2371-7. [DOI: 10.1093/ndt/gfp078] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Hendy GN, Guarnieri V, Canaff L. Chapter 3 Calcium-Sensing Receptor and Associated Diseases. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2009; 89:31-95. [DOI: 10.1016/s1877-1173(09)89003-0] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Drüeke TB, Ritz E. Treatment of secondary hyperparathyroidism in CKD patients with cinacalcet and/or vitamin D derivatives. Clin J Am Soc Nephrol 2008; 4:234-41. [PMID: 19056615 DOI: 10.2215/cjn.04520908] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The discovery of the calcium-sensing receptor (CaR) 15 yr ago was rapidly followed by the development of drugs modulating its activity, the so-called calcimimetics (increasing the CaR signal) and calcilytics (decreasing the CaR signal). The indication for calcimimetics is treatment of primary and secondary hyperparathyroidism, whereas calcilytics have potential for treatment of osteoporosis. A large number of clinical studies has shown that cinacalcet, the only presently available calcimimetic, effectively reduces serum parathyroid hormone in dialysis patients with secondary hyperparathyroidism. In contrast to the effect of active vitamin D derivatives, it simultaneously decreases serum calcium and phosphorus. Experimental studies showed a concomitant decrease in parathyroid hyperplasia. In the treatment of secondary hyperparathyroidism of dialysis patients, important questions remain unresolved, for example, whether there are reasons to prefer calcimimetics to active vitamin D derivatives and whether combined administration offers advantages compared with calcimimetics or active vitamin D given in isolation. For lowering parathyroid hormone, available evidence from recent studies suggests that combination therapy should be preferred to single drug treatment because of less side-effects and greater efficacy in controlling parathyroid overfunction. Future randomized controlled trial must answer whether calcimimetics impact on cardiovascular events or survival and whether in this respect there are differences between vitamin D sterols and calcimimetics.
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Affiliation(s)
- Tilman B Drüeke
- INSERM Unité 845 and Service de Néphrologie, Hôpital Necker, Tour Lavoisier, Paris Cedex 15, France.
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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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Drüeke TB. Cinacalcet Treatment in Dialysis Patients with Secondary Hyperparathyroidism: Effects and Open Issues. Ther Apher Dial 2008; 12 Suppl 1:S2-12. [DOI: 10.1111/j.1744-9987.2008.00624.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Effect of cinacalcet on hypercalcemia and bone mineral density in renal transplanted patients with secondary hyperparathyroidism. Transplantation 2008; 86:413-7. [PMID: 18698244 DOI: 10.1097/tp.0b013e31817c13e1] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Persistent secondary hyperparathyroidism (SHP) is the most frequent cause of hypercalcemia observed in approximately 10% of renal transplanted (RT) patients 1 year after surgery. Persistent SHP with hypercalcemia is an important factor of bone loss after renal transplantation. This study prospectively evaluates the effects of cinacalcet therapy on serum calcium (SCa) and parathyroid hormone (PTH) blood levels, and basically on bone mineral density (BMD) in RT patients with persistent hyperparathyroidism. METHODS Nine RT patients (eight women, one man) with allograft function more than 6 months were included based on total SCa more than 10.5 mg/dL and intact parathyroid hormone (iPTH) concentration more than 65 pg/mL. After inclusion, patients started on a single daily oral dose of 30 mg of cinacalcet. At inclusion and every study visit blood levels of creatinine, Ca, P, alkaline phosphatase, iPTH 1,25- dihydroxyvitamin D3, and 25-hydroxyvitamin D3 were assessed. Baseline and at the end of study radial BMD were measured. Study follow-up was 12 months. RESULTS During the study period, SCa decreased from 11.72+/-0.39 to 10.03+/-0.54 mg/dL (P<0.001). iPTH decreased from 308.85+/-120.12 to 214.66+/-53.75 mg/dL (P<0.05). The mean serum creatinine decreased from 1.58+/-0.34 to 1.25+/-0.27 mg/dL (P=0.03) and the mean radial BMD increased from 0.881+/-0.155 to 0.965+/-0.123 gr/cm2 (P<0.05). There were no significant changes in the other parameters assessed. One patient was excluded for gastrointestinal intolerance. CONCLUSIONS In RT patients with hypercalcemia secondary to persistent SHP, cinacalcet corrects hypercalcemia and PTH, simultaneously improving BMD.
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Evenepoel P. Calcimimetics in chronic kidney disease: evidence, opportunities and challenges. Kidney Int 2008; 74:265-75. [DOI: 10.1038/ki.2008.166] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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de Francisco ALM. New strategies for the treatment of hyperparathyroidism incorporating calcimimetics. Expert Opin Pharmacother 2008; 9:795-811. [PMID: 18345956 DOI: 10.1517/14656566.9.5.795] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Hyperparathyroidism (HPT), characterised by increased parathyroid hormone (PTH) secretion and parathyroid hyperplasia, can be caused by physiologic defects in the parathyroid gland (primary HPT [PHPT]) or as a consequence of declining renal function (secondary HPT [SHPT]). OBJECTIVE To review the safety and efficacy of cinacalcet in the treatment of SHPT and PHPT. METHODS Studies indexed in NLM/PubMed investigating the safety, efficacy, and pharmacokinetics of cinacalcet for PHPT and SHPT and supporting preclinical evidence. RESULTS/CONCLUSION Recent evidence has demonstrated the efficacy of the calcimimetic cinacalcet in the treatment of PHPT and SHPT. Compared with traditional therapies such as vitamin D sterols and phosphate binders, cinacalcet treatment can allow an increased proportion of patients with SHPT to improve Kidney Disease Outcomes Quality Initiative (KDOQI) Bone Metabolism and Disease laboratory parameter target attainment. Recent evidence suggests that improvements in these biochemical parameters with cinacalcet can translate into improved morbidity and mortality. Cinacalcet lowers PTH and calcium in patients following renal transplantation, and also normalises serum calcium in patients with PHPT. Ongoing studies are focusing and future studies are likely to focus on the effect of cinacalcet on clinical outcomes and on novel strategies for the integration of cinacalcet with traditional therapies to improve serum PTH and mineral metabolism control.
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Affiliation(s)
- Angel L M de Francisco
- Servicio de Nefrologia, Hospital Universitario Valdecilla, Avda Valdecilla s/n, E-39008 Santander, Spain.
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Cinacalcet and the prevention of secondary hyperparathyroidism in rats with aldosteronism. Am J Med Sci 2008; 335:105-10. [PMID: 18277117 DOI: 10.1097/maj.0b013e318134f013] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND In rats receiving aldosterone/salt treatment (ALDOST), increased Ca2+ excretion leads to a fall in plasma-ionized Ca2+ and appearance of secondary hyperparathyroidism (SHPT) with parathyroid hormone (PTH)-mediated intracellular Ca2+ overloading inducing oxidative stress in diverse tissues. Parathyroidectomy prevents this scenario. Rats with ALDOST were cotreated with cinacalcet (Cina), a calcimimetic that raises the threshold of the parathyroids' Ca(2+)-sensing receptor. METHODS AND RESULTS We monitored plasma-ionized [Ca2+]o, PTH, and total Ca2+ in heart and peripheral blood mononuclear cells (PBMC), and evidence of oxidative stress in heart, PBMC, and plasma. Cina-treated rats for 4 weeks were compared with 4 weeks of ALDOST alone and with untreated age-/gender-matched controls. In comparison to controls, ALDOST led to a fall (P < 0.05) in Ca2+ (1.16 +/- 0.01 vs 1.03 +/- 0.01 mmol/L), which was not prevented by Cina (1.01 +/- 0.03 mmol/L); a rise (P < 0.05) in plasma PTH (36 +/- 7 vs 134 +/- 19 pg/mL) that was attenuated by Cina (69 +/- 12 pg/mL); increased (P < 0.05) cardiac [Ca2+] (3.92 +/- 0.25 vs 6.78 +/- 0.35 nEq/mg FFDT) and PBMC [Ca2+]i (29.8 +/- 2.3 vs 50.2 +/- 2.3 nmol/L), each of which was prevented with Cina (3.65 +/- 0.10 nEq/mg FFDT and 32.5 +/- 6.0 nmol/L, respectively); increased cardiac MDA (0.56 +/- 0.03 vs 0.94+/-0.07 nmol/mg protein) and PBMC H2O2 production (63.5 +/- 7.5 vs 154.0 +/- 25.2 mcb) and reduced (P < 0.05) plasma alpha1-AP activity (39.8 +/- 0.6 vs 29.6 +/- 1.8 mM), each prevented by Cina (0.66 +/- 0.04 mmol/mg protein, 58.2 +/- 12.7 mcb and 37.0 +/- 1.2 mM, respectively). CONCLUSIONS PTH-mediated intracellular Ca2+ overloading accounts for the induction of oxidative stress in diverse tissues in rats with aldosteronism and which can be prevented by Cina.
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Levy R, Gal-Moscovici A. Renal Osteodystrophy in Peritoneal Dialysis: Special Considerations. Perit Dial Int 2008. [DOI: 10.1177/089686080802802s03] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Bone disease is one of the most challenging complications in patients with chronic kidney disease. Today, it is considered to be part of a complex systemic disorder manifested by disturbances of mineral metabolism and vascular calcifications called chronic kidney disease – mineral bone disorder (CKD-MBD). The term renal osteodystrophy is reserved to define the specific bone lesion in CKD-MBD, whose spectrum ranges from high turnover to low turnover disease. Phosphate retention, decreased serum calcium, and 1,25-dihydroxy vitamin D synthesis are involved in the pathogenesis of high bone turnover. However, the various therapeutic approaches (calcium supplements, phosphate binders, and vitamin D metabolites, among others), the renal replacement modality (hemodialysis or continuous ambulatory peritoneal dialysis), and the types of patients to whom dialysis is offered (more patients who are diabetic or older, or both) may influence the evolution of the bone disorder. As a result, recent studies have reported a greater prevalence of adynamic forms of renal osteodystrophy, especially in diabetic and peritoneal dialysis patients. The present article reviews, for patients treated with peritoneal dialysis, the pathophysiologic mechanisms involved in the evolution and perpetuation of this bone disease and the therapeutic modalities for treating and preventing adynamic bone.
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Affiliation(s)
- Ronen Levy
- Division of Nephrology and Hypertension and Department of Medicine, Hadassah Medical Organization, Hebrew University, Ein-Karem, Jerusalem, Israel
| | - Anca Gal-Moscovici
- Division of Nephrology and Hypertension and Department of Medicine, Hadassah Medical Organization, Hebrew University, Ein-Karem, Jerusalem, Israel
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Ogata H, Koiwa F, Kinugasa E, Akizawa T. CKD-MBD: impact on management of kidney disease. Clin Exp Nephrol 2007; 11:261-268. [DOI: 10.1007/s10157-007-0492-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2007] [Accepted: 07/12/2007] [Indexed: 11/29/2022]
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Chertow GM, Martin KJ. Current and Future Therapies for the Medical Management of Secondary Hyperparathyroidism. Semin Dial 2007. [DOI: 10.1111/j.1525-139x.1998.tb00363.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Fryer RM, Segreti JA, Widomski DL, Franklin PH, Banfor PN, Koch KA, Nakane M, Wu-Wong JR, Cox BF, Reinhart GA. Systemic activation of the calcium sensing receptor produces acute effects on vascular tone and circulatory function in uremic and normal rats: focus on central versus peripheral control of vascular tone and blood pressure by cinacalcet. J Pharmacol Exp Ther 2007; 323:217-26. [PMID: 17636005 DOI: 10.1124/jpet.107.123901] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Calcium-sensing receptor (CaR) activation decreases serum parathyroid hormone (PTH) and Ca2+ and, despite long-term reductions in mean arterial blood pressure (MAP), may produce acute hypertension in rats, an effect we hypothesized was mediated by constriction of multiple vascular beds. Rats were subjected to 5/6 nephrectomy (NX) or no surgery (Normal); at 7 to 8 weeks, uremia animals were anesthetized and instrumented to record MAP and regional blood flow (carotid, mesenteric, and hindlimb). Cinacalcet [N-(1-naphthalen-1-ylethyl)-3-[3-(trifluoromethyl)phenyl]-propan-1-amine; 1, 3, and 10 mg/kg; 30 min/dose] was infused over 90 min. In NX rats, cinacalcet dose-dependently decreased ionized calcium (iCa2+), elicited a 90% reduction in PTH, and produced dose-dependent self-limiting increases in MAP (from 119 +/- 6 to 129 +/- 5, 142 +/- 4, and 145 +/- 3 mm Hg at the end of each infusion). At 1 mg/kg, carotid vascular resistance (CVR) and mesenteric vascular resistance (MVR) increased to 16 +/- 6 and 18 +/- 6% above baseline, respectively. Hindlimb vascular resistance (HVR) also trended upward (13 +/- 8%). At 3 mg/kg, increases in CVR (38 +/- 10%), MVR (40 +/- 8%), and HVR (39 +/- 14%) were exacerbated; at 10 mg/kg, values remained at or near these levels. The effects of cinacalcet in Normal rats were similar to NX and were attenuated by ganglionic blockade with hexamethonium at low doses but remained significantly elevated at higher doses. Thus, CaR activation acutely increases MAP in uremic and nonuremic rats, responses that occur in parallel to vasoconstriction in multiple vascular beds through both a central and peripheral mechanism of action. Moreover, subsequent mechanistic studies suggest that increases in MAP produced by cinacalcet may be mediated by reduced tonic NO synthase-dependent NO production subsequent to reductions in blood iCa2+.
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Affiliation(s)
- Ryan M Fryer
- Integrative Pharmacology, Global Pharmaceutical Research and Development, Abbott Laboratories, 100 Abbott Park Road, Abbott Park, IL 60064-6119, USA.
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Rodriguez ME, Almaden Y, Cañadillas S, Canalejo A, Siendones E, Lopez I, Aguilera-Tejero E, Martin D, Rodriguez M. The calcimimetic R-568 increases vitamin D receptor expression in rat parathyroid glands. Am J Physiol Renal Physiol 2007; 292:F1390-5. [PMID: 17200160 DOI: 10.1152/ajprenal.00262.2006] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We previously demonstrated that extracellular calcium regulates vitamin D receptor (VDR) expression by parathyroid cells. Since the calcimimetic R-568 potentiates the effects of calcium on the calcium-sensing receptor, it was hypothesized that administration of R-568 may result in increased VDR expression in parathyroid tissue. In vitro studies of the effect of R-568 on VDR mRNA and protein were conducted in cultures of whole rat parathyroid glands and human hyperplastic parathyroid glands. In vivo studies in Wistar rats examined the effect of R-568 and calcitriol alone and in combination. Incubation of rat parathyroid glands in vitro with R-568 (0.001–1 μM) resulted in a dose-dependent decrease in parathyroid hormone (PTH) secretion and an increase in VDR expression (mean ± SE). Incubation in 1 mM calcium + 0.001 μM R-568 elicited an increase in VDR mRNA (306 ± 46%) similar to the maximum increase detected with 1.5 mM calcium (330 ± 42%). In vivo, VDR mRNA was increased after administration of R-568 (168 ± 9%, P < 0.001 vs. control) or calcitriol (198 ± 16%, P < 0.001 vs. control). Treatment with R-568 also increased VDR protein in normal rat parathyroid glands and in human parathyroid glands with diffuse, but not nodular, hyperplasia. In conclusion, the present study shows that the calcimimetic R-568 exerts a stimulatory effect on VDR expression in the parathyroid glands of study models and provides additional evidence for the use of calcimimetics in the treatment of secondary hyperparathyroidism.
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Affiliation(s)
- M E Rodriguez
- Unidad de Investigacion, Servicio de Nefrologia, Hospital Universitario Reina Sofia, Cordoba, Spain
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Lazar E, Hebert K, Poma T, Stankus N. Long-term outcomes of cinacalcet and paricalcitol titration protocol for treatment of secondary hyperparathyroidism. Am J Nephrol 2007; 27:274-8. [PMID: 17429197 DOI: 10.1159/000101727] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2006] [Accepted: 03/12/2007] [Indexed: 11/19/2022]
Abstract
Long-term outcomes of combined cinacalcet and paricalcitol therapy for secondary hyperparathyroidism (SHPT) in patients failing traditional therapies with phosphate binders and active vitamin D compound analogs are not well described. We implemented a titration protocol for cinacalcet and paricalcitol and assessed its long-term effects on bone metabolism and disease in hemodialysis (HD) patients. Thirty-five patients were started on 30 mg of cinacalcet daily. After 12 months, median cinacalcet dose was 60 mg. There was a 33% increase in number of patients receiving paricalcitol. Average corrected serum calcium (Ca) decreased from 9.5 to 8.8 mg/dl (p = 0.003, 95% CI 0.34-1.04); phosphorus (P) from 6.2 to 5.5 mg/dl (p = 0.047, 95% CI 0.01-1.34); Ca x P product from 58 to 48 (p = 0.001, 95% CI 4.2-15.7); and intact PTH (iPTH) from 426 +/- 274 to 300 +/- 228 pg/ml (p = 0.03, 95% CI 19.3-401.7). Number of patients achieving three or more K/DOQI criteria increased by 29% (p = 0.009).
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Affiliation(s)
- Eric Lazar
- Department of Medicine, University of Chicago, Chicago, Ill. 60637, USA
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Abstract
The extracellular calcium (Ca(o)2+)-sensing receptor (CaR) enables the parathyroid glands and other CaR-expressing cells to sense alterations in the level of Ca(o)2+ and to respond with changes in function that are directed at normalizing the blood calcium concentration. In addition to the parathyroid gland, the kidney is a key site for Ca(o)2(+)-sensing that enables it to make physiologically relevant alterations in divalent cation and water metabolism. Several disorders of Ca(o)2(+)-sensing arise from inherited or acquired abnormalities that "reset" the serum calcium concentration upward or downward. Inactivating mutations produce a benign form of hypercalcemia when present in the heterozygous state, termed Familial Hypocalciuric Hypercalcemia (FHH), while homozygous mutations produce a much more severe hypercalcemic disorder resulting from marked hyperparathyroidism, called Neonatal Severe Hyperparathyroidism (NSHPT). Activating mutations cause a hypocalcemic syndrome of varying severity, termed autosomal dominant hypocalcemia or hypoparathyroidism. Inactivating or activating antibodies directed at the CaR produce the expected hyper- or hypocalcemic syndromes, respectively. "Calcimimetic" CaR activators and "calcilytic" CaR antagonists have been developed. The calcimimetics are currently in use for controlling severe hyperparathyroidism in patients receiving dialysis treatment for end stage renal disease or with parathyroid cancer. Calcilytics are being evaluated as a means of inducing a "pulse" in the circulating parathyroid hormone (PTH) concentration, which would mimic that resulting from injection of PTH, an established anabolic form of treatment for osteoporosis.
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Affiliation(s)
- E M Brown
- Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA.
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Abstract
Renal osteodystrophy (ROD), a metabolic bone disease accompanying chronic renal failure (CRF), is a major clinical problem in pediatric nephrology. Growing and rapidly remodeling skeletal systems are particularly susceptible to the metabolic and endocrine disturbances in CRF. The pathogenesis of ROD is complex and multifactorial. Hypocalcemia, phosphate retention, and low levels of 1,25 dihydroxyvitamin D(3) related to CRF result in disturbances of bone metabolism and ROD. Delayed diagnosis and treatment of bone lesions might result in severe disability. Based on microscopic findings, renal bone disease is classified into two main categories: high- and low-turnover bone disease. High-turnover bone disease is associated with moderate and severe hyperparathyroidism. Low-turnover bone disease includes osteomalacia and adynamic bone disease. The treatment of ROD involves controlling serum calcium and phosphate levels, and preventing parathyroid gland hyperplasia and extraskeletal calcifications. Serum calcium and phosphorus levels should be kept within the normal range. The calcium-phosphorus product has to be <5 mmol(2)/L(2) (60 mg(2)/dL(2)). Parathyroid hormone (PTH) levels in children with CRF should be within the normal range, but in children with end-stage renal disease PTH levels should be two to three times the upper limit of the normal range. Drug treatment includes intestinal phosphate binding agents and active vitamin D metabolites. Phosphate binders should be administered with each meal. Calcium carbonate is the most widely used intestinal phosphate binder. In children with hypercalcemic episodes, sevelamer, a synthetic phosphate binder, should be introduced. In children with CRF, ergocalciferol (vitamin D(2)), colecalciferol (vitamin D(3)), and calcifediol (25-hydroxyvitamin D(3)) should be used as vitamin D analogs. In children undergoing dialysis, active vitamin D metabolites alfacalcidol (1alpha-hydroxy-vitamin D(3)) and calcitriol (1,25 dihydroxyvitamin D(3)) are applied. In recent years, a number of new drugs have emerged that hold promise for a more effective treatment of bone lesions in CRF. This review describes the current approach to the diagnosis and treament of ROD.
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Affiliation(s)
- Helena Ziólkowska
- Department of Pediatrics and Nephrology, Medical University of Warsaw, Warsaw, Poland.
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Chattopadhyay N, Brown EM. Role of calcium-sensing receptor in mineral ion metabolism and inherited disorders of calcium-sensing. Mol Genet Metab 2006; 89:189-202. [PMID: 16919492 DOI: 10.1016/j.ymgme.2006.07.003] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2006] [Revised: 07/11/2006] [Accepted: 07/11/2006] [Indexed: 12/28/2022]
Abstract
The extracellular calcium-sensing receptor (CaR), a G protein-coupled receptor that resides on the parathyroid cell surface negatively regulates secretion of parathyroid hormone (PTH). The CaR is functionally expressed in bone, kidney, and gut--the three major calcium-translocating organs involved in calcium homeostasis. Further studies are needed to define fully the homeostatic roles of the CaR in tissues that are involved in systemic extracellular calcium [Ca(2+)](o) homeostasis. The role of the CaR in regulating calcium metabolism has been greatly clarified by the identification and studies of genetically determined disorders that either activate or inactivate the receptor. Antibodies to the CaR that either activate or inactivate it produce syndromes resembling the corresponding genetic diseases. Expression of the CaR is significantly reduced in primary and secondary hyperparathyroidism, which could contribute to the defective [Ca(2+)](o)-sensing in these conditions. Calcimimetics act as CaR agonists or allosteric activators and thereby potentiate the effects of [Ca(2+)](o) on parathyroid cell function. This kind of pharmacological manipulation of the CaR is now used for the treatment of hyperparathyroid states, whereby the calcimimetics increase the activation of the CaR at any given level of extracellular calcium. Calcimimetics are also an effective element in the treatment of secondary hyperparathyroidism, particularly in dialysis patients, by virtue of reducing plasma levels of PTH, calcium and phosphate.
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Affiliation(s)
- Naibedya Chattopadhyay
- Division of Endocrinology, Central Drug Research Institute, Chattar Manzil Palace, Lucknow 226 001, India.
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de Francisco ALM. Medical therapy of secondary hyperparathyroidism in chronic kidney disease: old and new drugs. Expert Opin Pharmacother 2006; 7:2215-24. [PMID: 17059378 DOI: 10.1517/14656566.7.16.2215] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Secondary hyperparathyroidism (SHPT), a common complication of chronic kidney disease, is characterised by elevated serum levels of parathyroid hormone, parathyroid hyperplasia, excessive bone resorption and increased risk for cardiovascular morbidity. The stringent metabolic targets proposed by the National Kidney Foundation Kidney Disease Outcomes Quality Initiative (K/DOQI) for patients with SHPT are difficult to achieve using conventional treatment regimens. Several new agents, including new vitamin D sterols and phosphate binders, as well as a novel class of compounds--the calcimimetics--have been developed in recent years. This review examines new and traditional therapies for SHPT and how these can best be utilised in order to achieve the new K/DOQI targets.
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Affiliation(s)
- Angel L M de Francisco
- Hospital Universitario Valdecilla, Servicio de Nefrologia, Santander, Spain. martinal@unican
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Abstract
It has long been recognized that the secretion of PTH by chief cells in the parathyroid gland is regulated by extracellular ionized calcium. The molecular mechanism by which extracellular Ca2+ performs this feat was deduced by the cloning of the extracellular calcium-sensing receptor (CaSR) in 1993 in the laboratories of Brown and Hebert. The CaSR is a G protein-coupled cell surface receptor that belongs to family 3 of the GPCR superfamily. The CaSR senses the extracellular ionic activity of the divalent minerals Ca2+ and Mg2+ and translates this information, via a complex array of cellular signaling pathways, to modify cell and tissue function. Genetic studies have demonstrated that the activity of this receptor determines the steady-state plasma calcium concentration in humans by regulating key elements in the calcium homeostatic system. CaSR agonists (calcimimetics) and antagonists (calcilytics) have been identified and have provided both current and potential therapies for a variety of disorders. Calcimimetics can effectively reduce PTH secretion in all forms of hyperparathyroidism. They are likely to become a major therapy for secondary hyperparathyroidism associated with renal failure and for treatment of certain patients with primary hyperparathyroidism. On the therapeutic horizon are calcilytics that can transiently increase PTH and may prove useful in the treatment of osteoporosis.
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Affiliation(s)
- Steven C Hebert
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06520-8026, USA.
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Abstract
Parathyroid hyperplasia, oversecretion of parathyroid hormone (PTH), and hyperparathyroid bone disease are characteristic features of chronic uremia; they develop early in the course of uremia and often in a progressive way. This review focuses on the potential for arrest or regression of hyperparathyroid-induced bone disease. For this purpose, the review addresses investigations that have used bone histology and not investigations that indirectly attempted to demonstrate changes in the skeleton by measurements of bone mineral density or laboratory indices of bone turnover, other than PTH. A prerequisite for inducing regression of the hyperparathyroid bone disease is a significant suppression of PTH secretion or reversal of hyperparathyroidism and uremia. It is concluded, on the basis of paired bone biopsy studies in patients with established hyperparathyroid bone disease, that bone histology can be improved or normalized after treatment that diminishes PTH levels. Oversuppression of PTH levels, however, might lead to adynamic bone disease.
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Affiliation(s)
- Klaus Olgaard
- University of Copenhagen, Department of Nephrology, P2132, Rigshospitalet, 9 Blegdamsvej, DK-2100 Copenhagen, Denmark.
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