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Christie CR, Achenie LEK, Ayeni OB. A Model-Based Approach to Diagnosing Hypercalcemia. Ind Eng Chem Res 2023. [DOI: 10.1021/acs.iecr.2c03525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Christopher R. Christie
- Department of Chemical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia24060, United States
| | - Luke E. K. Achenie
- Department of Chemical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia24060, United States
| | - Oluwafemi B. Ayeni
- Department of Chemical Engineering, Obafemi Awolowo University, Ile-Ife, Osun state220101, Nigeria
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2
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Predictive factors requiring high-dose evocalcet in hemodialysis patients with secondary hyperparathyroidism. PLoS One 2022; 17:e0279078. [PMID: 36512619 PMCID: PMC9746983 DOI: 10.1371/journal.pone.0279078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 11/28/2022] [Indexed: 12/15/2022] Open
Abstract
The dosage of evocalcet required to control serum parathyroid hormone (PTH) levels varies among secondary hyperparathyroidism (SHPT) patients. This post hoc analysis evaluated the dose-dependent efficacy of evocalcet on serum intact PTH (iPTH) levels, corrected calcium (Ca) and phosphate (P) levels, and safety, in an evaluation period (week 28 to week 30) by stratifying the previous phase 3 data with the final evocalcet dosages (low 1-2 mg [131 patients], medium 3-4 mg [90 patients], high 5-8 mg [92 patients]), and identified pre-treatment patient characteristics predicting the use of higher final evocalcet dosages via univariate and multivariate logistic regression models. At the end of the study at week 30, the median serum iPTH level was higher and the achievement ratio for the target range of Japanese Society for Dialysis Therapy (60-240 pg/mL) was lower in the final high-dose subgroup (216 pg/mL and 58%, respectively) than in the other subgroups (low: 149 pg/mL and 79%; medium: 149 pg/mL and 73%, respectively). Among the three subgroups, the mean serum corrected Ca and P levels demonstrated similar trends, and similar ratio of patients achieved the target range (corrected Ca, 8.4-10 mg/dL; P, 3.5-6.0 mg/dL) from week 28 to week 30. No dose-dependent safety concerns were identified. Younger age, prior cinacalcet use, higher serum levels of iPTH and corrected Ca, procollagen type 1 N-terminal propeptide, intact fibroblast growth factor-23, and larger maximum parathyroid gland volume were significantly associated with final high-dose evocalcet (p < 0.05 in all cases). Patients requiring final high-dose evocalcet had pre-treatment characteristics indicating severe SHPT, leading to a lower final achievement rate for the target PTH levels of Japanese Society for Dialysis Therapy. Therefore, the early initiation of evocalcet treatment for SHPT is critical. Trial registration: This trial was registered as follows: ClinicalTrials.gov: NCT02549391 and JAPIC: JapicCTI-153013.
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The Calcium Loading Test in Primary Hyperparathyroidism – Does it Provide Useful Information? ACTA MEDICA BULGARICA 2022. [DOI: 10.2478/amb-2022-0023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Abstract
Objective: to describe the results from intravenous calcium loads in patients with suspected PHPT.
Methods: This was a retrospective cross-sectional study with inpatients’ data review. Baseline serum calcium, phosphates, magnesium, creatinine, alkaline phosphatase, beta-crosslinks were recorded. The calcium loading had been performed after an overnight fasting. Calcium gluconate 0.25 mmol/kg body weight (10 mg/kg) dissolved in 0.9% Sodium Chloride was infused intravenously for 3 hours. Blood samples for total serum calcium, phosphates and iPTH were drawn before and up to 60 minutes after the calcium load. The intact parathyroid hormone (iPTH) and 25(OH)-vitamin D were determined by electro-hemi-luminescence (Elecsys, Roche Diagnostics). The PTH inhibition rate in % (PTH-IR), the calcium increment, the ratio R (ΔPTH/ΔCalcium) and the product P (calcium X PTH at test end) were calculated.
Results: 23 patients with PHPT had complete data from calcium loading tests. The PTH suppression was < 30% in 17.4% of the participants, 30% to 50% – in 21.7% and > 50% in the remaining 60.9%. One patient displayed PTH suppression > 75%. The Ratio R was < 4.0 in all but one patient. Product P was above 1100 mg/dl x pg/ml in 9 participants (39.1%). Sixteen patients (69.6%) had positive localization results from US or SPECT-CT. The level of PTH suppression was not related to any parameter except the volume of the suspected lesion.
Conclusion: The calcium loading test was unable to differentiate the forms of PHPT. It did not add great value in the diagnostic work-up of PHPT.
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Chandran M, Bilezikian JP, Salleh NM, Ying H, Lau J, Lee J, deJong MC, Chan Maung A, Parameswaran R. Hungry bone syndrome following parathyroidectomy for primary hyperparathyroidism in a developed country in the Asia Pacific. A cohort study. Osteoporos Sarcopenia 2022; 8:11-16. [PMID: 35415277 PMCID: PMC8987324 DOI: 10.1016/j.afos.2022.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 03/04/2022] [Accepted: 03/15/2022] [Indexed: 12/03/2022] Open
Abstract
Objectives We sought to assess the incidence of hungry bone syndrome (HBS) following parathyroidectomy (PTX) for primary hyperparathyroidism (PHPT) in a cohort of multi-ethnic patients from a developed country in the Asia Pacific. Methods One hundred and sixty-four patients who underwent PTX for PHPT between 2012 and 2019 at the 2 largest public hospitals in Singapore were identified. HBS was defined as serum albumin-adjusted calcium ≤ 2.1 mmol/L with normal or raised serum intact parathyroid hormone (iPTH) levels, manifesting on or after the 3rd day, or persisting for more than 3 days post-operatively. Results Chinese constituted 73.8%, Malays 12.2%, Indians 9.8%, and other races 4.3%. HBS developed in 4 patients (2.4%) (95% CI, 0.8%–6.5%). HBS patients had significantly longer in-hospital stays; 20 days [IQR:15–22] vs 2 days [IQR:1–3]; P < 0.001in those who did not develop HBS. There was no difference in the incidence of HBS stratifying for age, sex, vitamin D status, or use of preoperative anti-resorptive medication use. For every 10 unit increase in iPTH and alkaline phosphatase (ALP) levels, the risk of HBS increased by 14% and 11%; RR (95% CI), 1.14 (1.05–1.21) and 1.11 (1.03–1.18), respectively. Conclusions The low incidence of HBS in multi-ethnic patients undergoing PTX by multiple surgeons for PHPT at the 2 largest public hospitals that see the most such patients in Singapore, a developed country, is consistent with the asymptomatic/milder form of presentation of PHPT in the developed world.
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Affiliation(s)
- Manju Chandran
- Osteoporosis and Complicated Metabolic Bone Disorders Unit, Department of Endocrinology, Singapore General Hospital, Singapore
- Corresponding author. Osteoporosis and Bone Metabolism Unit, Department of Endocrinology, Singapore General Hospital, 20 College Road, ACADEMIA, 169856, Singapore.
| | - John P. Bilezikian
- Division of Endocrinology, Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | | | - Hao Ying
- National Public Health and Epidemiology Unit, National Centre for Infectious Diseases, Singapore
| | - Joel Lau
- Department of Endocrine Surgery, National University Hospital, Singapore
| | - James Lee
- Department of Endocrine Surgery, National University Hospital, Singapore
| | - Mechteld C. deJong
- Department of Endocrine Surgery, National University Hospital, Singapore
| | - Aye Chan Maung
- Department of Endocrinology, Singapore General Hospital, Singapore
- Department of Endocrinology, Ealing Hospital, London North West Healthcare NHS Trust, United Kingdom
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Koiwa F, Tokunaga S, Asada S, Endo Y, Fukagawa M, Akizawa T. Efficacy of Evocalcet in Previously Cinacalcet-Treated Secondary Hyperparathyroidism Patients. Kidney Int Rep 2021; 6:2830-2839. [PMID: 34805635 PMCID: PMC8589700 DOI: 10.1016/j.ekir.2021.08.020] [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: 04/27/2021] [Revised: 08/12/2021] [Accepted: 08/16/2021] [Indexed: 12/12/2022] Open
Abstract
Introduction Evocalcet is a recently approved calcimimetic agent for secondary hyperparathyroidism (SHPT). In this study, the efficacy and safety of once-daily oral evocalcet were evaluated in patients without prior cinacalcet use (nonusers) and previously treated patients (users). Methods This post hoc analysis of a previous phase III head-to-head comparison study included SHPT patients treated with evocalcet with or without prior cinacalcet use. Endpoints included trends in the median intact and whole parathyroid hormone (PTH), mean corrected calcium, phosphate, and bone metabolic markers, and whole-to-intact PTH ratios throughout the 30-week study period; proportions of patients achieving target intact PTH, corrected calcium, and phosphate at weeks 28 to 30; and adverse drug reactions (ADRs). Results This study included 127 nonusers and 190 users with significant differences in age; duration of dialysis; use of intravenous vitamin D receptor activators; levels of intact PTH, corrected calcium, tartrate-resistant acid phosphatase 5b, procollagen type 1 N-terminal-propeptide; and largest parathyroid gland volume (P < 0.05 for all characteristics) between 2 groups at baseline. Users required higher evocalcet dosages than nonusers. Similar efficacy results were found in the 2 groups except for a significantly higher proportion of nonusers achieving the intact PTH target (81.6% vs 67.1%, difference [95% confidence interval], −14.5% [−24.59, −3.34]), and a significant reduction in largest parathyroid gland volume from week 0 to week 30 (−120.6 [567.2] mm3, P = 0.043). No difference was found in ADRs between the 2 groups. Conclusion Treatment with evocalcet is effective and safe irrespective of prior cinacalcet treatment in SHPT patients.
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Affiliation(s)
- Fumihiko Koiwa
- Division of Nephrology, Department of Internal Medicine, Showa University Fujigaoka Hospital, Yokohama, Japan
| | - Shin Tokunaga
- Medical Affairs Department, Kyowa Kirin Co., Ltd., Tokyo, Japan.,R&D Division, Kyowa Kirin Co., Ltd., Tokyo, Japan
| | - Shinji Asada
- Medical Affairs Department, Kyowa Kirin Co., Ltd., Tokyo, Japan
| | - Yuichi Endo
- R&D Division, Kyowa Kirin Co., Ltd., Tokyo, Japan
| | - Masafumi Fukagawa
- Division of Nephrology, Endocrinology, and Metabolism, Department of Internal Medicine, Tokai University School of Medicine, Kanagawa, Japan
| | - Tadao Akizawa
- Division of Nephrology, Department of Medicine, Showa University School of Medicine, Tokyo, Japan
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Kobylecki CJ, Nordestgaard BG, Afzal S. Plasma Ionized Calcium and Risk of Cardiovascular Disease: 106 774 Individuals from the Copenhagen General Population Study. Clin Chem 2021; 67:265-275. [PMID: 33418574 DOI: 10.1093/clinchem/hvaa245] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 09/29/2020] [Indexed: 01/04/2023]
Abstract
BACKGROUND Circulating total calcium or albumin-adjusted calcium is a risk factor for cardiovascular disease. As the biologically active ionized calcium is a physiologically more relevant measure and its association with cardiovascular disease is poorly understood, we tested the hypothesis that high plasma ionized calcium is associated with higher risk of myocardial infarction and ischemic stroke in individuals in the general population. METHODS We included 106 774 individuals from the Copenhagen General Population Study, and defined hypocalcemia and hypercalcemia by the lowest and highest 2.5 percentiles, respectively, using the central 95% reference interval. Information on myocardial infarction and ischemic stroke was from registries and risks calculated using Cox regression and Fine and Gray competing-risks regression. RESULTS During a median follow-up of 9.2 years, 4932 individuals received a diagnosis of either myocardial infarction or ischemic stroke. Hypercalcemia was associated with subdistribution hazard ratios of 1.67 (95%CI: 1.05-2.67) for myocardial infarction, 1.28 (0.81-2.02) for ischemic stroke, and of 1.54 (1.10-2.15) for the combined endpoint compared to individuals with plasma ionized calcium within the reference interval; hypocalcemia was not associated with cardiovascular disease. In models using plasma ionized calcium as a continuous variable, the associations were nonlinear; above the median, each 0.1 mmol/L higher plasma ionized calcium was associated with a hazard ratio of 1.31(1.02-1.68) for myocardial infarction, 1.21 (0.95-1.54) for ischemic stroke, and of 1.28 (1.08-1.53) for the combined endpoint. CONCLUSIONS High plasma ionized calcium is associated with higher risk of myocardial infarction and ischemic stroke compared to plasma ionized calcium within the reference interval.
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Affiliation(s)
- Camilla J Kobylecki
- Department of Clinical Biochemistry, Herlev and Gentofte Hospital, Copenhagen University Hospital, Copenhagen, Denmark.,The Copenhagen General Population Study, Herlev and Gentofte Hospital, Copenhagen University Hospital, Copenhagen, Denmark
| | - Børge G Nordestgaard
- Department of Clinical Biochemistry, Herlev and Gentofte Hospital, Copenhagen University Hospital, Copenhagen, Denmark.,The Copenhagen General Population Study, Herlev and Gentofte Hospital, Copenhagen University Hospital, Copenhagen, Denmark.,Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Shoaib Afzal
- Department of Clinical Biochemistry, Herlev and Gentofte Hospital, Copenhagen University Hospital, Copenhagen, Denmark.,The Copenhagen General Population Study, Herlev and Gentofte Hospital, Copenhagen University Hospital, Copenhagen, Denmark.,Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Gleaves E, Nanney JM, Syed HR, Boyareddigari S. Acute Refractory Hypocalcemia in a 51-Year-Old Male With a History of 1,1-Difluoroethane Inhalation. Cureus 2021; 13:e13693. [PMID: 33824835 PMCID: PMC8012268 DOI: 10.7759/cureus.13693] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Hypocalcemia is a common electrolyte derangement that is most associated with parathryoid hormone or vitamin D abnormalities. Less common causes that most providers are aware of include hyperphosphatemia, acute pancreatitis, chronic kidney disease, and sepsis. However, certain populations are at risk for less common, but no less dangerous, causes. One such cause is 1,1-difluoroethane, an organofluorine that is used as a propellant in aerosol sprays and is commonly abused. 1,1-Difluoroethane has been noted to cause severe hypocalcemia by accumulation of the metabolite fluorocitrate in tissues. Here, we present the case of a 51-year-old male with severe hypocalcemia and multiple rib fractures following a fall, with recent history of tibial fracture. The patient had a medical history of osteoporosis with numerous fractures and chronic steroid use. He admitted to using keyboard cleaner as an inhalant for the previous month, which was found to contain 1,1-difluoroethane. Previous case reports on 1,1-difluoroethane inhalation have not reported a patient with preexisting osteoporosis or refractory hypocalcemia.
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Affiliation(s)
- Evan Gleaves
- Internal Medicine, University of Kentucky, Bowling Green, USA
| | - Jacob M Nanney
- College of Medicine, University of Kentucky, Lexington, USA
| | - Hassnain R Syed
- Internal Medicine, University of Kentucky, Bowling Green, USA
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Keller EX, De Coninck V, Pietropaolo A, Somani B, Haymann JP, Daudon M. Metabolic Evaluation: Place of the Calcium Load Test: How, When, For Whom, and Why? Eur Urol Focus 2021; 7:26-30. [PMID: 33419710 DOI: 10.1016/j.euf.2020.12.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Revised: 11/29/2020] [Accepted: 12/24/2020] [Indexed: 11/26/2022]
Abstract
Most human urinary stones are calcium-based and are often associated with hypercalciuria. A simple test described in 1975 by Pak et al allows for pathogenic classification of hypercalciuria: the calcium load test (CLT). The CLT explores calcium homeostasis after a low-calcium diet and then a calcium load (typically oral administration of 1 g of elemental calcium). Only simple laboratory equipment is required. Inadequate calcium excretion after a calcium-free diet or a calcium load is suggestive of resorptive or absorptive hypercalciuria, respectively. The CLT is particularly valuable in diagnosing primary hyperparathyroidism, even in most early stages of this disease. PATIENT SUMMARY: Kidney stone formation can be linked to calcium metabolism. When high calcium levels are found in urine despite adequate diet changes, a calcium load test may help to understand the underlying mechanisms. Urine and blood levels are explored during a low-calcium diet phase, and after a calcium load phase in the test. The calcium load test is particularly advantageous for revealing abnormally high function of the parathyroid gland, which is called hyperparathyroidism.
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Affiliation(s)
- Etienne Xavier Keller
- Department of Urology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
| | | | - Amelia Pietropaolo
- University Hospital Southampton NHS Trust, University of Southampton, Southampton, UK
| | - Bhaskar Somani
- University Hospital Southampton NHS Trust, University of Southampton, Southampton, UK
| | - Jean-Philippe Haymann
- Service d'Explorations Fonctionnelles Multidisciplinaires, AP-HP, Hôpital Tenon, Sorbonne Université, Paris, France; INSERM UMR_S 1155, AP-HP, Hôpital Tenon, Sorbonne Université, Paris, France
| | - Michel Daudon
- Laboratoire CRISTAL, Hôpital Tenon, Sorbonne Université, Paris, France
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9
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Xiang T, Wang Y, Lan T, Zhou L. Calcium-mediated parathyroid hormone suppression test in uraemic secondary hyperparathyroidism. Nephrology (Carlton) 2020; 26:164-169. [PMID: 33058364 DOI: 10.1111/nep.13807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 10/04/2020] [Accepted: 10/11/2020] [Indexed: 02/05/2023]
Abstract
AIM The present study aimed to investigate the value of calcium-mediated parathyroid hormone (PTH) suppression test in evaluating the autonomic secretory function of parathyroid, and the management of uraemic secondary hyperparathyroidism (SHPT). METHODS Calcium-mediated PTH suppression test was performed in dialysis with SHPT, who were candidates for parathyroidectomy from June 2017 to December 2019 in our hospital. The PTH inhibition rate (PTH-IR) was calculated, and the correlation between PTH-IR and clinical indicators was explored. RESULTS Fifty-one subjects were included. PTH-IR was negatively correlated with baseline PTH (r = -0.35, P = .012), it was also correlated with dialysis years, coronary artery calcification score (CACS) and parathyroid mass (r = -0.397, P = .004; r = -0.327, P = .028; r = -0.363, P = .015), which were not found for baseline PTH. Forty-four patients underwent surgical treatment. According to the histological results, 26 patients presented with parathyroid non-nodular hyperplasia, and 18 patients presented with parathyroid nodular hyperplasia. The mass of parathyroid of patients with nodular hyperplasia was higher than that of patients with non-nodular hyperplasia (ρ = 0.01). The difference of the PTH-IR was not found between the two groups (ρ = 0.296). During the test, the highest serum calcium was 2.9 ± 0.4 mmol/L, which dropped to normal at the end of the test. CONCLUSION Parathyroid hormone inhibition rate might be a useful indicator in evaluating the autonomic secretory function of parathyroid and the progression of SHPT on top of intact PTH. Calcium-mediated PTH suppression test was safe in uraemic SHPT patients, but need to monitor for transient hypercalcaemia.
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Affiliation(s)
- Ting Xiang
- Division of Nephrology, Kidney Research Institute, West China Hospital of Sichuan University, Chengdu, China
| | - Yan Wang
- Division of Nephrology, Kidney Research Institute, West China Hospital of Sichuan University, Chengdu, China
| | - Tian Lan
- Division of Nephrology, Kidney Research Institute, West China Hospital of Sichuan University, Chengdu, China
| | - Li Zhou
- Division of Nephrology, Kidney Research Institute, West China Hospital of Sichuan University, Chengdu, China
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10
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Prospects of Parathyroid Hormone in Therapeutic Intervention. Int J Pept Res Ther 2019. [DOI: 10.1007/s10989-018-9744-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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11
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Janmaat CJ, van Diepen M, Gasparini A, Evans M, Qureshi AR, Ärnlöv J, Barany P, Elinder CG, Rotmans JI, Vervloet M, Dekker FW, Carrero JJ. Lower serum calcium is independently associated with CKD progression. Sci Rep 2018; 8:5148. [PMID: 29581540 PMCID: PMC5980097 DOI: 10.1038/s41598-018-23500-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 03/12/2018] [Indexed: 01/10/2023] Open
Abstract
Disturbances in calcium metabolism are common in individuals with chronic kidney disease (CKD), but whether they are associated with subsequent kidney function decline is less clear. In a CKD 3-5 cohort of 15,755 adult citizens of Stockholm with creatinine tests taken during 2006-2011 and concurrent calcium testing at cohort entry, we investigated the association between baseline serum calcium and the subsequent change in estimated glomerular filtration rate (eGFR, by CKD-EPI) decline using linear mixed models. Mean (SD) baseline corrected serum calcium was 9.6 (0.5) mg/dL. Mean (95%-confidence interval [CI]) eGFR decline was -0.82 (-0.90; -0.74) mL/min/1.73 m2/year. In advanced CKD stages, higher baseline serum calcium was associated with less rapid kidney function decline. The adjusted change (95%-CI) in eGFR decline associated with each mg/dL increase in baseline serum calcium was -0.10 (-0.28; 0.26), 0.39 (0.07; 0.71), 0.34 (-0.02; 0.70) and 0.68 (0.36; 1.00) mL/min/1.73 m2/year for individuals in CKD stage 3a, 3b, 4, and 5, respectively. In a subgroup of patients using vitamin D supplements, the association between baseline serum calcium and CKD progression was eliminated, especially in CKD stage 3b and 4. To conclude, in individuals with CKD stage 3b to 5, lower baseline corrected serum calcium, rather than higher baseline serum calcium, associated with a more rapid CKD progression. Lower serum corrected calcium seems to be indicative for vitamin D deficiency.
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Affiliation(s)
- Cynthia J Janmaat
- Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands.
| | - Merel van Diepen
- Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Marie Evans
- Department of Clinical Science, Karolinska Institutet, Stockholm, Sweden
| | | | - Johan Ärnlöv
- Department of Clinical Science, Karolinska Institutet, Stockholm, Sweden
| | - Peter Barany
- Department of Clinical Science, Karolinska Institutet, Stockholm, Sweden
| | - Carl-Gustaf Elinder
- Department of Clinical Science, Karolinska Institutet, Stockholm, Sweden
- Public Healthcare Services committee, Stockholm County Council, Stockholm, Sweden
| | - Joris I Rotmans
- Department of Nephrology, Leiden University Medical Center, Leiden, The Netherlands
| | - Marc Vervloet
- Department of Nephrology and Institute for Cardiovascular Research VU, VU University Medical Center, Amsterdam, The Netherlands
| | - Friedo W Dekker
- Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Juan Jesus Carrero
- Department of Clinical Science, Karolinska Institutet, Stockholm, Sweden
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
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12
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Sitges-Serra A. The PGRIS and parathyroid splinting concepts for the analysis and prognosis of protracted hypoparathyroidism. Gland Surg 2017; 6:S86-S93. [PMID: 29322026 DOI: 10.21037/gs.2017.07.16] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Most patients with hypocalcemia after total thyroidectomy will recover the parathyroid function in a few weeks, but some 20-30% of them will still be in the need for replacement therapy one month after surgery and about 5-10% of those will develop permanent hypoparathyroidism. Although postoperative hypocalcemia has been related to several demographic and metabolic causes, parathyroid hormone (PTH) decline, resulting from autotransplantation, inadvertent excision or devascularization of the parathyroid glands, is the common final pathway. The number of parathyroid glands remaining in situ (PGRIS) is a key variable to understand the pathogenesis of protracted hypoparathyroidism and the chances for restoration of the parathyroid function. Normal-high serum calcium concentration, probably achieved by a more intensive medical treatment at the time of hospital discharge, has been identified as an independent variable favoring recovery of the parathyroid function. This we refer to as parathyroid splinting, a hypothesis holding that putting the injured parathyroid parenchyma at rest after thyroidectomy may improve long-term outcome of protracted hypoparathyroidism.
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13
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Karin O, Alon U. Biphasic response as a mechanism against mutant takeover in tissue homeostasis circuits. Mol Syst Biol 2017; 13:933. [PMID: 28652282 PMCID: PMC5488663 DOI: 10.15252/msb.20177599] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Tissues use feedback circuits in which cells send signals to each other to control their growth and survival. We show that such feedback circuits are inherently unstable to mutants that misread the signal level: Mutants have a growth advantage to take over the tissue, and cannot be eliminated by known cell-intrinsic mechanisms. To resolve this, we propose that tissues have biphasic responses in and the signal is toxic at both high and low levels, such as glucotoxicity of beta cells, excitotoxicity in neurons, and toxicity of growth factors to T cells. This gives most of these mutants a frequency-dependent selective disadvantage, which leads to their elimination. However, the biphasic mechanisms create a new unstable fixed point in the feedback circuit beyond which runaway processes can occur, leading to risk of diseases such as diabetes and neurodegenerative disease. Hence, glucotoxicity, which is a dangerous cause of diabetes, may have a protective anti-mutant effect. Biphasic responses in tissues may provide an evolutionary stable strategy that avoids invasion by commonly occurring mutants, but at the same time cause vulnerability to disease.
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Affiliation(s)
- Omer Karin
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Uri Alon
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
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14
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Schlosser K, Zielke A, Rothmund M. Medical and Surgical Treatment for Secondary and Tertiary Hyperparathyroidism. Scand J Surg 2016; 93:288-97. [PMID: 15658670 DOI: 10.1177/145749690409300407] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Prevention and treatment of secondary hyperparathyroidism (SHPT) in patients on chronic maintenance hemodialysis and of tertiary hyperparathyroidism (THPT) in patients after kidney transplantation is a challenge for the nephrologist and for the surgeon. Indication and results of medical and surgical therapy for SHPT and THPT have remained under discussion during the last decades. This review resumes the current medical and surgical strategies for patients with SHPT and THPT.
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Affiliation(s)
- K Schlosser
- Department of Visceral, Thoracic and Vascular Surgery, Philipps-University, Marburg, Germany.
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Lai V, Yen TWF, Doffek K, Carr AA, Carroll TB, Fareau GG, Evans DB, Wang TS. Delayed Calcium Normalization After Presumed Curative Parathyroidectomy is Not Associated with the Development of Persistent or Recurrent Primary Hyperparathyroidism. Ann Surg Oncol 2016; 23:2310-4. [PMID: 27006125 DOI: 10.1245/s10434-016-5190-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2015] [Indexed: 11/18/2022]
Abstract
BACKGROUND Following parathyroidectomy for primary hyperparathyroidism (pHPT), serum calcium levels typically normalize relatively quickly. The purpose of this study was to identify potential factors associated with delayed normalization of calcium levels despite meeting intraoperative parathyroid hormone (IOPTH) criteria and to determine whether this phenomenon is associated with higher rates of persistent pHPT. METHODS This was a retrospective review of 554 patients who underwent parathyroidectomy for sporadic pHPT from January 2009 to July 2013. Patients who underwent presumed curative parathyroidectomy and had elevated POD0 calcium levels (>10.2 mg/dL) were matched 1:2 for age and gender to control patients with normal POD0 calcium levels. RESULTS Of the 554 patients, 52 (9 %) had an elevated POD0 Ca (median 10.7, range 10.3-12.2). Compared with the control group, these patients had higher preoperative calcium (12 vs. 11.1, p < 0.001) and PTH (144 vs. 110 pg/mL, p = 0.004) levels and lower 25OH vitamin D levels (26 vs. 31 pg/mL; p = 0.024). Calcium normalization occurred in 64, 90, and 96 % of patients by postoperative days (POD) 1, 14, and 30, respectively. There was no difference in rates of single-gland disease or cure rates between the groups. CONCLUSIONS After presumed curative parathyroidectomy, nearly 10 % of patients had transiently persistent hypercalcemia. Most of these patients had normal serum calcium levels within the first 2 weeks and did not have increased rates of persistent pHPT. Immediate postoperative calcium levels do not predict the presence of persistent pHPT, and these patients may not require more stringent follow-up.
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Affiliation(s)
| | - Tina W F Yen
- Division of Surgical Oncology, Department of Surgery, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Kara Doffek
- Division of Surgical Oncology, Department of Surgery, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Azadeh A Carr
- Division of Surgical Oncology, Department of Surgery, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Ty B Carroll
- Endocrine Center and Clinics, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Gilbert G Fareau
- Division of Clinical Endocrinology, Metabolism, and Nutrition, Department of Medicine, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Douglas B Evans
- Division of Surgical Oncology, Department of Surgery, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Tracy S Wang
- Division of Surgical Oncology, Department of Surgery, Medical College of Wisconsin, Milwaukee, WI, USA.
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Parker VJ, Gilor C, Chew DJ. Feline hyperparathyroidism: pathophysiology, diagnosis and treatment of primary and secondary disease. J Feline Med Surg 2015; 17:427-39. [PMID: 25896242 PMCID: PMC10816244 DOI: 10.1177/1098612x15581134] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
PRACTICAL RELEVANCE Hyperparathyroidism exists in primary and secondary forms. Primary hyperparathyroidism has typically been considered a disease that uncommonly affects cats, but this condition is more prevalent than previous diagnoses would suggest. Secondary hyperparathyroidism may be caused by either nutritional influences (ie, nutritional secondary hyperparathyroidism) or chronic kidney disease (ie, renal secondary hyperparathyroidism). Tertiary hyperparathyroidism has yet to be documented in veterinary medicine, but it is possible that this condition occurs in some cats following longstanding renal secondary hyperparathyroidism. CLINICAL CHALLENGES Diagnosis of this group of calcium metabolic disorders presents a number of challenges for the clinician. For example, clinical signs can be non-specific and, especially in the case of primary hyperparathyroidism, there is often a low index of suspicion for the disease; careful sample handling is required for testing of parathyroid hormone (PTH) and ionized calcium levels; and there is currently no feline-specific assay for PTH, which has implications for test sensitivity and interpretation of results. AIMS This article briefly outlines PTH and calcium physiology by way of introduction to a review of PTH measurement and interpretation. Various forms of feline hyperparathyroidism are then described, encompassing diagnosis and treatment options.
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Affiliation(s)
- Valerie J Parker
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, 601 Vernon L Tharp Street, Columbus, OH 43210, USA
| | - Chen Gilor
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, 601 Vernon L Tharp Street, Columbus, OH 43210, USA
| | - Dennis J Chew
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, 601 Vernon L Tharp Street, Columbus, OH 43210, USA
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Oltmann SC, Sippel RS. Surgical management of the patient with primary hyperparathyroidism. INTERNATIONAL JOURNAL OF ENDOCRINE ONCOLOGY 2015. [DOI: 10.2217/ije.14.34] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Abstract: The successful surgical management of primary hyperparathyroidism requires a surgeon with a clear understanding of both the embryology and anatomy of the parathyroid glands. While the majority of patients may only have a single diseased gland, there is no 100% confirmation that can be attained in the preoperative period. For this reason, even when imaging is suggestive of a single diseased gland, additional intraoperative adjuncts should be used. Intraoperative parathyroid hormone monitoring is the most commonly used adjunct. When preoperative localization is not possible, or intraoperative parathyroid hormone levels fail to meet criteria for successful resection, the patient requires a four gland exploration. Cure is not confirmed until normocalcemia is documented for at least 6 months after surgery.
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Affiliation(s)
- Sarah C Oltmann
- Department of Surgery, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390-9092, USA
| | - Rebecca S Sippel
- Department of Surgery, University of Wisconsin, 600 Highland Ave, K3/704, Madison, WI, 53792-7375, USA
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Abstract
CONTEXT A control engineering perspective provides a framework for representing important mechanistic details of the calcium (Ca) regulatory system efficiently. The resulting model facilitates the testing of hypotheses about mechanisms underlying the emergence of known Ca-related pathologies. OBJECTIVE The objective of this work is to develop a comprehensive computational model that will enable quantitative understanding of plasma Ca regulation under normal and pathological conditions. DESIGN Ca regulation is represented as an engineering control system where physiological subprocesses are mapped onto corresponding block components (sensor, controller, actuator, and process), and underlying mechanisms are represented by differential equations. The resulting model is validated with clinical observations of induced hypo- or hypercalcemia in healthy subjects, and its applicability is demonstrated by comparing model predictions of Ca-related pathologies to corresponding clinical data. RESULTS Our model accurately predicts clinical responses to induced hypo- and hypercalcemia in healthy subjects within a framework that facilitates the representation of Ca-related pathologies in terms of control system component defects. The model also enables a deeper understanding of the emergence of pathologies and the testing of hypotheses about related features of Ca regulation-for example, why primary hyperparathyroidism and hypoparathyroidism arise from "controller defects." CONCLUSIONS The control engineering framework provides an efficient means of organizing the subprocesses constituting Ca regulation, thereby facilitating a fundamental understanding of this complex process. The resulting validated model's predictions are consistent with clinically observed short- and long-term dynamic characteristics of the Ca regulatory system in both healthy and diseased patients. The model also enables simulation of currently infeasible clinical tests and generates predictions of physiological variables that are currently not measurable.
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Affiliation(s)
- Christopher R Christie
- Department of Chemical Engineering (C.R.C., L.E.K.A.), Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24060; and Department of Chemical Engineering (B.A.O.), University of Delaware, Newark, Delaware 19716
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Pruett WA, Hester RL. Parathyroid hormone secretion by multiple distinct cell populations, a time dynamic mathematical model. Physiol Rep 2014; 2:e00231. [PMID: 24744900 PMCID: PMC3966243 DOI: 10.1002/phy2.231] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Revised: 10/07/2013] [Accepted: 10/08/2013] [Indexed: 11/09/2022] Open
Abstract
The acute response of parathyroid hormone to perturbations in serum ionized calcium ([Ca2+]) is physiologically complex, and poorly understood. The literature provides numerous observations of quantitative and qualitative descriptions of parathyroid hormone (PTH) dynamics. We present a physiologically based mathematical model of PTH secretion constructed from mechanisms suggested in the literature, and validated against complex [Ca2+] clamping protocols from human data. The model is based on two assumptions. The first is that secretion is a fraction of cellular reserves, with the fraction being determined by the kinetics of [Ca2+] with its receptor. The second is that there are multiple distinct populations of parathyroid cells, with different secretory parameters. The steady state and transient PTH secretion responses of the model are in agreement with human experimental PTH responses to different hypocalcemia and hypercalcemia stimuli. This mathematical model suggests that a population of secreting cells is responsible for the PTH secretory dynamics observed experimentally. We present a physiologically based mathematical model of parathyroid hormone (PTH) secretion constructed from mechanisms suggested in the literature, and validated against complex [Ca2+] clamping protocols from human data. The steady state and transient PTH secretion responses of the model are in agreement with human experimental PTH responses to different hypo and hypercalcemia stimuli. This mathematical model suggests that a population of secreting cells is responsible for the PTH secretory dynamics observed experimentally.
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Affiliation(s)
- William A Pruett
- Department of Physiology, Center for Computational Medicine, University of Mississippi Medical Center, Jackson, 39216, Mississippi
| | - Robert L Hester
- Department of Physiology, Center for Computational Medicine, University of Mississippi Medical Center, Jackson, 39216, Mississippi
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Huang CY, Zheng CM, Wu CC, Lo L, Lu KC, Chu P. Effects of pamidronate and calcitriol on the set point of the parathyroid gland in postmenopausal hemodialysis patients with secondary hyperparathyroidism. Nephron Clin Pract 2013; 122:93-101. [PMID: 23635416 DOI: 10.1159/000350431] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Accepted: 02/26/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS Secondary hyperparathyroidism may worsen after the administration of pamidronate in postmenopausal hemodialysis (HD) patients. The aim of this study was to evaluate the short-term effect of coadministration of calcitriol and pamidronate on dynamic parathyroid hormone (PTH) secretion. METHODS Fifteen postmenopausal women undergoing regular HD with serum intact PTH levels of >200 pg/ml were enrolled. The PTH-ionized calcium (iCa) curve was evaluated by the response to hypo- and hypercalcemia induced with 1 and 4 mEq/l of dialysate calcium, respectively. Parameters were compared after pamidronate was administered and after coadministration of pamidronate and calcitriol. Changes in serum levels of maximal serum PTH (PTHmax), basal PTH (PTHbase) and minimal PTH (PTHmin) were evaluated. RESULTS Pamidronate therapy resulted in a decrease in predialysis basal plasma iCa (p < 0.05) and an increase in PTHmax (p < 0.01), PTHbase (p < 0.01) and PTHmin (p < 0.01). The change in serum iCa and PTH was reversed after the coadministration of calcitriol and pamidronate. CONCLUSION Our study demonstrated that pamidronate therapy is associated with a reduced plasma iCa and increased PTH secretion. These adverse effects may be reversed by calcitriol. These findings suggest that in considering pamidronate treatment in postmenopausal patients with osteoporosis receiving HD, it might be safer to add calcitriol to prevent the increased PTH secretion.
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Affiliation(s)
- Chung-Yu Huang
- Department of Medicine, Show-Chwan Memorial Hospital, Changhua, Taiwan, ROC
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Jin J, Mitchell J, Shin J, Berber E, Siperstein AE, Milas M. Calculating an individual maxPTH to aid diagnosis of normocalemic primary hyperparathyroidism. Surgery 2012; 152:1184-92. [DOI: 10.1016/j.surg.2012.08.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Accepted: 08/13/2012] [Indexed: 11/16/2022]
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Harvey A, Hu M, Gupta M, Butler R, Mitchell J, Berber E, Siperstein A, Milas M. A New, Vitamin D-Based, Multidimensional Nomogram for the Diagnosis of Primary Hyperparathyroidism. Endocr Pract 2012; 18:124-131. [DOI: 10.4158/ep10389.or] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
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23
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The apparent hysteresis in hormone-agonist relationships. J Theor Biol 2012; 296:1-5. [DOI: 10.1016/j.jtbi.2011.11.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Revised: 11/14/2011] [Accepted: 11/22/2011] [Indexed: 11/24/2022]
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Naranda J, Ekart R, Pečovnik-Balon B. Total parathyroidectomy with forearm autotransplantation as the treatment of choice for secondary hyperparathyroidism. J Int Med Res 2011; 39:978-87. [PMID: 21819732 DOI: 10.1177/147323001103900333] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Chronic kidney disease-mineral and bone disease (CKD-MBD) is associated with uraemic bone disease, vascular calcification, reduced quality of life and reduced survival. This study evaluated the efficacy of parathyroidectomy (PTX) with autotransplantation in improving short-term and long-term outcomes. Dialysis patients who underwent PTX showed significantly more favourable biochemical parameters after PTX. These changes were accompanied by a lower coronary artery calcification score, reduced thickness of the intimae media and comparable bone mineral density measures compared with control dialysis patients who did not undergo PTX. Despite the risk of a substantially lower intact parathyroid hormone level postoperatively that might lead to adynamic bone disease, none of the patients reported clinical signs of this disease, such as bone pain or fractures. In conclusion, PTX with autotransplantation led to improvement of CKD-MBD so may be considered in patients with secondary hyperparathyroidism that is resistant to treatment with vitamin D analogues and calcimimetics.
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Affiliation(s)
- J Naranda
- Faculty of Medicine, University of Maribor, Maribor, Slovenia.
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Madorin C, Owen RP, Fraser WD, Pellitteri PK, Radbill B, Rinaldo A, Seethala RR, Shaha AR, Silver CE, Suh MY, Weinstein B, Ferlito A. The surgical management of renal hyperparathyroidism. Eur Arch Otorhinolaryngol 2011; 269:1565-76. [PMID: 22101574 DOI: 10.1007/s00405-011-1833-2] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Accepted: 10/30/2011] [Indexed: 01/22/2023]
Abstract
Secondary and tertiary hyperparathyroidism (HPT) develop in patients with renal failure due to a variety of mechanisms including increased phosphorus and fibroblast growth factor 23 (FGF23), and decreased calcium and 1,25-dihydroxy vitamin D levels. Patients present with various bone disorders, cardiovascular disease, and typical laboratory abnormalities. Medical treatment consists of controlling hyperphosphatemia, vitamin D/analog and calcium administration, and calcimimetic agents. Improved medical therapies have led to a decrease in the use of parathyroidectomy (PTX). The surgical indications include parathyroid hormone (PTH) levels >800 pg/ml associated with hypercalcemia and/or hyperphosphatemia despite medical therapy. Other indications include calciphylaxis, fractures, bone pain or pruritis. Transplant recipients often show decreased PTH, calcium and phosphorus levels, but some will have persistent HPT. Evidence suggests that PTX may cause deterioration in renal graft function in the short-term calling into the question the indications for PTX in these patients. Pre-operative imaging is only occasionally helpful except in re-operative PTX. Operative approaches include subtotal PTX, total PTX with or without autotransplantation, and possible thymectomy. Each approach has its proponents, advantages and disadvantages which are discussed. Intraoperative PTH monitoring has a high positive predictive value of cure but a poor negative predictive value and therefore is of limited utility. Hypocalcemia is the most common complication requiring aggressive calcium administration. Benefits of surgery may include improved survival, bone mineral density and alleviation of symptoms.
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Affiliation(s)
- Catherine Madorin
- Department of Surgery, Division of Metabolic, Endocrine and Minimally Invasive Surgery, Mount Sinai School of Medicine, New York, NY, USA
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Zhao L, Zhang MJ, Zhao HY, Sun LH, Li JL, Tao B, Wang WQ, Ning G, Liu JM. PTH inhibition rate is useful in the detection of early-stage primary hyperparathyroidism. Clin Biochem 2011; 44:844-8. [DOI: 10.1016/j.clinbiochem.2011.03.142] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Revised: 03/19/2011] [Accepted: 03/23/2011] [Indexed: 12/01/2022]
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VULPIO C, MARESCA G, DISTASIO E, CACACI S, PANOCCHIA N, LUCIANI G, BOSSOLA M. Switch from calcitriol to paricalcitol in secondary hyperparathyroidism of hemodialysis patients: Responsiveness is related to parathyroid gland size. Hemodial Int 2011; 15:69-78. [DOI: 10.1111/j.1542-4758.2010.00514.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Hultin H, Edfeldt K, Sundbom M, Hellman P. Left-shifted relation between calcium and parathyroid hormone in obesity. J Clin Endocrinol Metab 2010; 95:3973-81. [PMID: 20519351 DOI: 10.1210/jc.2009-2822] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
BACKGROUND A condition resembling secondary hyperparathyroidism (HPT), including raised levels of PTH and normal levels of serum calcium, has been reported in obesity. A plausible reason may be vitamin D deficiency, but conflicting data have been reported. OBJECTIVE Our objective was to investigate calcium homeostasis in obese individuals with emphasis on the function of the parathyroid glands. DESIGN AND INTERVENTION Morbidly obese patients (mean body mass index=46.6+/-6) were examined for their status of calcium homeostasis. A subset was thoroughly investigated with calcium-citrate (CiCa) clamping. PATIENTS Of 108 morbidly obese patients, 11 underwent CiCa clamping as well as 21 healthy volunteers of normal weight and 15 with primary HPT (pHPT). Large patient cohorts of normal individuals and pHPT patients were also used as comparisons. OUTCOME MEASURES AND RESULTS All obese individuals had normal serum calcium and creatinine levels. Mean levels of 25-OH-vitamin D3 in serum were low, 53 nmol/liter (reference range 75-250 nmol/liter). Mean intact plasma PTH was 5.1 pmol/liter (reference range 1.1-6.9 pmol/liter). There was a significant positive correlation between PTH and duration of obesity. CiCa clamping in obese subjects revealed a remarkably high sensitivity for calcium and a left-shifted relation between plasma calcium and PTH (set point) compared with the normal population. CiCa clamping in pHPT patients demonstrated a right-shifted PTH-Ca curve. CONCLUSION Although vitamin D levels in the obese individuals were low, few displayed overt signs of secondary HPT. The CiCa clamping implied a disturbance in the calcium homeostasis comparable to early renal insufficiency, with a left-shifted Ca-PTH curve and a lower set point compared with the normal population.
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Affiliation(s)
- Hella Hultin
- Department of Surgery, University Hospital, SE-751 85 Uppsala, Sweden.
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Shrestha RP, Hollot CV, Chipkin SR, Schmitt CP, Chait Y. A mathematical model of parathyroid hormone response to acute changes in plasma ionized calcium concentration in humans. Math Biosci 2010; 226:46-57. [DOI: 10.1016/j.mbs.2010.04.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2009] [Revised: 04/06/2010] [Accepted: 04/12/2010] [Indexed: 10/19/2022]
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Peterson MC, Riggs MM. A physiologically based mathematical model of integrated calcium homeostasis and bone remodeling. Bone 2010; 46:49-63. [PMID: 19732857 DOI: 10.1016/j.bone.2009.08.053] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2009] [Revised: 08/24/2009] [Accepted: 08/26/2009] [Indexed: 12/30/2022]
Abstract
Bone biology is physiologically complex and intimately linked to calcium homeostasis. The literature provides a wealth of qualitative and/or quantitative descriptions of cellular mechanisms, bone dynamics, associated organ dynamics, related disease sequela, and results of therapeutic interventions. We present a physiologically based mathematical model of integrated calcium homeostasis and bone biology constructed from literature data. The model includes relevant cellular aspects with major controlling mechanisms for bone remodeling and calcium homeostasis and appropriately describes a broad range of clinical and therapeutic conditions. These include changes in plasma parathyroid hormone (PTH), calcitriol, calcium and phosphate (PO4), and bone-remodeling markers as manifested by hypoparathyroidism and hyperparathyroidism, renal insufficiency, daily PTH 1-34 administration, and receptor activator of NF-kappaB ligand (RANKL) inhibition. This model highlights the utility of systems approaches to physiologic modeling in the bone field. The presented bone and calcium homeostasis model provides an integrated mathematical construct to conduct hypothesis testing of influential system aspects, to visualize elements of this complex endocrine system, and to continue to build upon iteratively with the results of ongoing scientific research.
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Affiliation(s)
- Mark C Peterson
- Amgen, Inc., One Amgen Center Drive, MS 28-3-B, Thousand Oaks, CA 91320, USA.
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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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de Francisco ALM, Izquierdo M, Cunningham J, Piñera C, Palomar R, Fresnedo GF, Amado JA, Unzueta MG, Arias M. Calcium-mediated parathyroid hormone release changes in patients treated with the calcimimetic agent cinacalcet. Nephrol Dial Transplant 2008; 23:2895-901. [PMID: 18424820 DOI: 10.1093/ndt/gfn191] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The parathyroid-calcium (Ca(2+)-PTH) curve expresses modulation of parathyroid hormone (PTH) secretion by the parathyroid gland as a function of changing extracellular Ca(2+) concentration. Patients with hyperparathyroidism (HPT) show a rightward shift of the curve compared with controls, suggesting a reduced sensitivity of parathyroid cells to Ca(2+). Increasing the sensitivity of the parathyroid gland to extracellular Ca(2+) by manipulation of the Ca(2+)-sensing receptor (CaR) may have therapeutic potential. Calcimimetics allosterically modify CaR and render it more sensitive to extracellular Ca(2+), accounting for the simultaneous reduction of Ca(2+) and PTH seen in most patients. METHODS The Ca(2+)-PTH curve was evaluated in 10 haemodialysis patients, with baseline intact PTH levels >300 pg/ml in two haemodialysis sessions, one before and the other after (range, 9-22 weeks) cinacalcet treatment. In each session a 2-h low-dialysate Ca(2+) concentration was used to induce hypocalcaemia and maximally stimulate PTH secretion, followed immediately by a 2-h high-dialysate Ca(2+) concentration to induce hypercalcaemia and maximally inhibit PTH secretion. RESULTS Significant decreases in ionized Ca(2+) and intact PTH were observed following cinacalcet treatment. Cinacalcet treatment also led to a decrease in the set point for Ca(2+) and to a leftward shift of the Ca(2+)-PTH curve. Significant differences were present in all segments of the Ca(2+)-PTH curves. CONCLUSION The pathological rightward shift of the Ca(2+)-PTH curve seen in many HPT patients may be reversed by cinacalcet treatment.
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Affiliation(s)
- Angel L M de Francisco
- Servicio de Nefrología, Hospital Universitario Valdecilla, Avda Valdecilla, s/n, Santander, 39008, Spain.
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Felsenfeld AJ, Rodríguez M, Aguilera-Tejero E. Dynamics of parathyroid hormone secretion in health and secondary hyperparathyroidism. Clin J Am Soc Nephrol 2007; 2:1283-305. [PMID: 17942777 DOI: 10.2215/cjn.01520407] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This review examines the dynamics of parathyroid hormone secretion in health and in various causes of secondary hyperparathyroidism. Although most studies of parathyroid hormone and calcium have focused on the modification of parathyroid hormone secretion by serum calcium, the relationship between parathyroid hormone and serum calcium is bifunctional because parathyroid hormone also modifies serum calcium. In normal animals and humans, factors such as phosphorus and vitamin D modify the basal parathyroid hormone level and the maximal parathyroid hormone response to hypocalcemia. Certain medications, such as lithium and estrogen, in normal individuals and sustained changes in the serum calcium concentration in hemodialysis patients change the set point of calcium, which reflects the serum calcium concentration at which parathyroid hormone secretion responds. Hypocalcemia increases the basal/maximal parathyroid hormone ratio, a measure of the relative degree of parathyroid hormone stimulation. The phenomenon of hysteresis, defined as a different parathyroid hormone value for the same serum calcium concentration during the induction of and recovery from hypo- and hypercalcemia, is discussed because it provides important insights into factors that affect parathyroid hormone secretion. In three causes of secondary hyperparathyroidism--chronic kidney disease, vitamin D deficiency, and aging--factors that affect the dynamics of parathyroid hormone secretion are evaluated in detail. During recovery from vitamin D deficiency, the maximal parathyroid hormone remains elevated while the basal parathyroid hormone value rapidly becomes normal because of a shift in the set point of calcium. Much remains to be learned about the dynamics of parathyroid hormone secretion in health and secondary hyperparathyroidism.
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Affiliation(s)
- Arnold J Felsenfeld
- Department of Medicine, VA Greater Los Angeles Healthcare System, 11301 Wilshire Boulevard, Los Angeles, CA 90073, USA.
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Abstract
Renal osteodystrophy (ROD) develops as the early stages of chronic renal failure (CRF) and covers a spectrum of bone changes observed in the uraemic patient, which extend from high remodelling bone disease (frequently known as osteitis fibrosa) to low turnover, or adynamic disease. Between these two extremes there are also cases of bone mineralization compromised in variable degrees, as is the case of 'mixed bone disease' and osteomalacia. The dynamic process of bone remodelling is compromised in CRF, and a positive or negative bone balance can be observed in uraemic patients. In addition to the classic modulators of bone remodelling, like parathyroid hormone, calcitriol and calcitonin, other factors were recently identified as significant modulators of osteoblast and osteoclast activation in uraemic patients. In fact, different cytokines and growth factors, acting at an autocrine or paracrine level, seem to play a relevant role in the bone and mineral changes observed in uraemia. Recently, observations have been made of the development of more sensitive and specific techniques to assay different biochemical markers of bone turnover and mineral metabolism. Analogously, new contributions of conventional bone histology, bone immunocytochemistry and molecular biology, which enabled the understanding of some etiopathogenic mechanisms of ROD, were observed.
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Affiliation(s)
- A Ferreira
- Hospital Curry Cabral, Universidade Nova de Lisboa, Lisbon, Portugal.
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36
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Abstract
Hyperparathyroidism (HPT) is a significant clinical concern for patients with a variety of diseases, notably the secondary HPT associated with chronic kidney disease requiring dialysis. Secondary HPT is associated with elevated para-thyroid hormone (PTH) levels, decreased levels of 1,25 dihydroxyvitamin D, and disordered mineral levels (usually high calcium and phosphorus). If not controlled, secondary HPT can result in bone disease, vascular calcification, and ultimately, patient mortality. Established, conventional therapies, such as 1,25dihydroxyvitamin D analogues (vitamin D analogues) and phosphate binders, have proven to be inadequate in enabling patients to meet the National Kidney Foundation's-Kidney Disease Outcomes Quality Initiative (NKF-K/DOQI) treatment goals for PTH, calcium and phosphorus levels. A novel therapeutic, cinacalcet HCl (formerly AMG 073; Sensipar in the US and Mimpara in Europe; Amgen, Inc.), binds directly to the calcium-sensing receptor (CaR) on the cells of the parathyroid gland, increasing the receptor's sensitivity to calcium and reducing PTH, serum calcium and phosphorus levels. Treatment with cinacalcet in clinical trials has safely and effectively improved achievement of the NKF-K/DOQI goals. Cinacalcet has also reduced serum calcium levels in patients with primary HPT, including parathyroid carcinoma, in the clinical trial setting. Evidence suggesting the utility of cinacalcet in these diseases and the potential for additional therapeutic applications will be discussed.
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37
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Abstract
Secondary hyperparathyroidism (SHPT) remains an inevitable consequence of untreated chronic uremia. It is the result of a combination of phosphate (P) retention, failure of calcitriol synthesis, and hypocalcemia. Therapies used to correct these abnormalities, namely active vitamin D replacement, calcium (Ca) supplementation, and phosphate (P) restriction, have moderate efficacy but are prone to unacceptable side-effects. However, there have been new developments in the control of P, vitamin D replacement and modulation of the Ca sensing receptor (CaSR) using calcimimetics. Sevelamer, and in the near future lanthanum, are offering a reasonable level of P control without the toxicities inherent with either aluminum- or Ca-based phosphate binders, and other phosphate binders are in development. 'Non calcemic' vitamin D metabolites include 22-oxacalcitriol, paricalcitol, and doxercalciferol. In various experimental models 22-oxacalcitriol, in particular, exhibits impressive suppression of parathyroid hormone (PTH) with minimal calcemia, although it has been less impressive when compared with calcitriol in controlled studies in hemodialysis (HD) patients. The advantages of these agents over conventional treatment with calcitriol or alfacalcidol remain uncertain. Cinacalcet, a calcimimetic agent that up-regulates the sensitivity of the CaSR in parathyroid and other cells, is a new type of therapy for SHPT that simultaneously reduces the concentrations of PTH, Ca, and P in HD patients, enabling a significant number to achieve K/DOQI or other national guidelines. The extent to which this new therapy will improve clinical outcomes remains uncertain. In conclusion, with the advent of new therapies the emphasis in the management of SHPT has evolved to incorporate reduction of Ca loading, control of PTH within specific target ranges, and avoidance of hypercalcemia, hyperphosphatemia and elevation of the calcium phosphorus product.
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Affiliation(s)
- John Cunningham
- The Center for Nephrology, The Royal Free and University College Medical School, London, UK.
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38
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Davey RA, Morris HA. The effects of salmon calcitonin-induced hypocalcemia on bone metabolism in ovariectomized rats. J Bone Miner Metab 2005; 23:359-65. [PMID: 16133685 DOI: 10.1007/s00774-005-0613-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2004] [Accepted: 03/22/2005] [Indexed: 10/25/2022]
Abstract
The ovariectomized rat has proved to be a most useful model for preclinical testing of potential therapies for osteoporosis. We describe the immediate effects of a single treatment with salmon calcitonin (sCT) on calcium homeostasis and bone turnover markers in 6-month-old sham and ovariectomized (ovx) rats at 15 days postovariectomy. Rats were fasted for 24 h prior to and following administration of 0.3 microg/kg body weight sCT. Blood specimens were collected at 0 (pretreatment), 2, 4, and 8 h. Urine samples were collected during the intervening periods. sCT treatment produced a decrease in blood ionized calcium at 2 h posttreatment in sham and ovx rats (P < 0.001), which was exaggerated in the ovx rats (P < 0.001). Increased parathyroid hormone (PTH) levels (P < 0.001) accompanied the hypocalcemia in ovx rats. Furthermore, PTH levels were significantly higher in ovx rats compared with sham rats for the same ionized calcium range of 1.275-1.300 mmol/l (P < 0.05). sCT treatment in sham rats increased urine hydroxyproline (UHyp) at 6 h posttreatment (P < 0.01). In conclusion, the calcitonin-induced hypocalcemia and secondary hyperparathyroidism was more pronounced in the ovariectomized rats, consistent with the actions of calcitonin in states of increased bone turnover induced by estrogen deficiency. This study highlights the importance of considering the actions of PTH and estrogen status when interpreting changes in calcium homeostasis and bone turnover following treatment with calcitonin in rodent models and provides further evidence for a potential role of estrogen in parathyroid function.
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Affiliation(s)
- Rachel A Davey
- Hanson Institute, Frome Road, Adelaide, South Australia, Australia.
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Rodriguez M, Nemeth E, Martin D. The calcium-sensing receptor: a key factor in the pathogenesis of secondary hyperparathyroidism. Am J Physiol Renal Physiol 2004; 288:F253-64. [PMID: 15507543 DOI: 10.1152/ajprenal.00302.2004] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Serum calcium levels are regulated by the action of parathyroid hormone (PTH). Major drivers of PTH hypersecretion and parathyroid cell proliferation are the hypocalcemia and hyperphosphatemia that develop in chronic kidney disease patients with secondary hyperparathyroidism (SHPT) as a result of low calcitriol levels and decreased kidney function. Increased PTH production in response to systemic hypocalcemia is mediated by the calcium-sensing receptor (CaR). Furthermore, as SHPT progresses, reduced expression of CaRs and vitamin D receptors (VDRs) in hyperplastic parathyroid glands may limit the ability of calcium and calcitriol to regulate PTH secretion. Current treatment for SHPT includes the administration of vitamin D sterols and phosphate binders. Treatment with vitamin D is initially effective, but efficacy often wanes with further disease progression. The actions of vitamin D sterols are undermined by reduced expression of VDRs in the parathyroid gland. Furthermore, the calcemic and phosphatemic actions of vitamin D mean that it has the potential to exacerbate abnormal mineral metabolism, resulting in the formation of vascular calcifications. Effective new treatments for SHPT that have a positive impact on mineral metabolism are clearly needed. Recent research shows that drugs that selectively target the CaR, calcimimetics, have the potential to meet these requirements.
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Affiliation(s)
- Mariano Rodriguez
- Unidad de Investigación, Servicio de Nefrologia, Hospital Universitario Reina Sofía, Avd Menendez Pidal s/n, 14004 Cordoba, Spain.
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40
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Raef H, Ingemansson S, Sobhi S, Sultan A, Ahmed M, Chaudhry M. The effect of vitamin D status on the severity of bone disease and on the other features of primary hyperparathyroidism (pHPT) in a vitamin D deficient region. J Endocrinol Invest 2004; 27:807-12. [PMID: 15648543 DOI: 10.1007/bf03346273] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A clear relationship between vitamin D status and the clinical indices of primary hyperparathyroidism (pHPT) severity has not been convincingly established. We proposed that such a relationship might exist, in so far as vitamin D deficiency could contribute to the severity of metabolic bone disease and promote the growth of the parathyroid tumor. Accordingly, we undertook a retrospective study and analyzed the clinical, biochemical, radiological and histopathological findings in a group of 49 patients who underwent parathyroidectomy at our center. Patients who had skeletal X-rays were grouped, according to their X-ray findings, in group A (19 patients; 45%) if they had severe bone changes, or group B (23 patients; 55%) if they had mild or no bone changes. Patients were also stratified according to their 25-hydroxyvitamin D (25-OHD) levels in tertiles. The 2 groups were compared using Fisher's exact test or analysis of variance as appropriate. Group A patients were younger (p=0.001), had more musculoskeletal symptoms (p=0.0003), and complained more frequently of fatigue (p=0.02). They had higher alkaline phosphatase (AP; p=0.0002), PTH index (p=0.0007), and serum Ca level (p=0.006). There were more patients from the lower and middle vitamin D tertiles and fewer patients from the upper vitamin D tertile in group A (p=0.02). Post-operative severe hypo-calcemia was more prevalent in group A patients (p<0.0001). Resected parathyroid tumors were larger in size in group A patients (p=0.01), and weighed more (p=0.01). There was a positive correlation between the weight of the parathyroid tumor and the PTH index (p=0.002), and AP level (p=0.0007). We concluded that vitamin D deficiency is a contributing factor to both the severity of bone disease and the high activity of parathyroid tumors seen in many patients with pHPT in vitamin D deficient regions.
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Affiliation(s)
- H Raef
- Department of Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh, Kingdom of Saudi Arabia.
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41
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Etoh S, Murata T, Hasegawa Y, Miyahara Y, Ishimura A, Abe Y, Noda R, Ogahara S, Kaneoka H, Saito T. Relationship of predialytic intact parathyroid hormone on secondary hyperparathyroidism in chronic maintenance haemodialysis patients. Nephrology (Carlton) 2004; 9:161-6. [PMID: 15189177 DOI: 10.1111/j.1440-1797.2004.00248.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
METHODS AND RESULTS In order to clarify the predialytic factors influencing the onset of secondary hyperparathyroidism (SHPT) in patients on chronic maintenance haemodialysis, the time-course changes of serum levels of intact-PTH (i-PTH) during haemodialysis for 5 years were investigated. The subjects were 69 non-diabetic patients who had a serum aluminium level of less than 1.85 nmol/L at the end of observation. Patients were divided into two groups based on i-PTH levels obtained at the start of dialysis; the high group (H group) consisted of patients whose i-PTH levels were more than 22.00 pmol/L, the low group (L group) had levels less than 22.00 pmol/L. In the H group, i-PTH was 41.46 +/- 2.87 pmol/L at the start of dialysis (vs L group, P < 0.0001) and 15.82 +/- 2.85 pmol/L after haemodialysis initiation. In the L group, i-PTH levels did not significantly change and was 11.69 +/- 2.50 pmol/L 12 months after the start of dialysis (at the 12th month). However, at the 60th month, the i-PTH level was 33.24 +/- 5.30 pmol/L in the H group, and 9.85 +/- 2.13 pmol/L in the L group (P < 0.005). CONCLUSION It is suggested that control of i-PTH levels in the predialytic period may be important to suppress SHPT throughout haemodialysis.
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Affiliation(s)
- Satoshi Etoh
- Division of Nephrology and Rheumatology, Department of Internal Medicine, Fukuoka University School of Medicine and Kawanami Hospital Kidney Center, Fukuoka, Japan.
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42
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Lu KC, Yeung LK, Lin SH, Lin YF, Chu P. Acute effect of pamidronate on PTH secretion in postmenopausal hemodialysis patients with secondary hyperparathyroidism. Am J Kidney Dis 2004; 42:1221-7. [PMID: 14655194 DOI: 10.1053/j.ajkd.2003.08.023] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND The purpose of this study is to evaluate the acute effect of pamidronate on plasma ionized calcium (iCa) level reduction and dynamic parathyroid hormone (PTH) secretion in postmenopausal hemodialysis-dependent women with secondary hyperparathyroidism. METHODS Twelve postmenopausal women undergoing regular hemodialysis with serum intact PTH levels greater than 200 pg/mL (200 ng/L) were included in this study. Pamidronate was administered intravenously as a single dose of 15 mg in the last hour of hemodialysis. PTH responses to hypocalcemia and hypercalcemia induced with 1 mEq/L (0.5 mmol/L) and 4 mEq/L (2 mmol/L) of dialysate calcium, respectively, were evaluated before and 1 week after pamidronate therapy. RESULTS Pamidronate therapy resulted in a decrease in predialysis basal plasma iCa (iCa(base); P < 0.05) levels and an increase in maximal serum PTH (PTHmax; P < 0.001), basal PTH (PTHbase; P < 0.001), and minimal PTH levels (P < 0.001). The set point of serum calcium and the slope of the PTH-calcium curve were not altered by pamidronate therapy. An inverse correlation was present between iCa(base) and the PTHbase-PTHmax ratio before (r = -0.66; P < 0.05) and after (r = -0.84; P < 0.001) pamidronate therapy. CONCLUSION Our study shows that pamidronate therapy is associated with reduced plasma iCa levels and increased PTH secretion, resulting in aggravated secondary hyperparathyroidism. These findings suggest that secondary hyperparathyroidism may worsen after the administration of pamidronate, at least in the short term, in postmenopausal hemodialysis patients.
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MESH Headings
- Aged
- Chronic Kidney Disease-Mineral and Bone Disorder/blood
- Chronic Kidney Disease-Mineral and Bone Disorder/drug therapy
- Chronic Kidney Disease-Mineral and Bone Disorder/etiology
- Diphosphonates/adverse effects
- Diphosphonates/pharmacology
- Diphosphonates/therapeutic use
- Female
- Humans
- Hypercalcemia/etiology
- Hyperparathyroidism, Secondary/blood
- Hyperparathyroidism, Secondary/chemically induced
- Hyperparathyroidism, Secondary/etiology
- Hyperparathyroidism, Secondary/physiopathology
- Hypocalcemia/etiology
- Kidney Failure, Chronic/blood
- Kidney Failure, Chronic/complications
- Kidney Failure, Chronic/therapy
- Middle Aged
- Osteoporosis, Postmenopausal/blood
- Osteoporosis, Postmenopausal/complications
- Osteoporosis, Postmenopausal/drug therapy
- Pamidronate
- Parathyroid Hormone/metabolism
- Postmenopause/physiology
- Renal Dialysis
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Affiliation(s)
- Kuo-Cheng Lu
- Department of Medicine, Division of Nephrology, Tri-Service General Hospital, National Defense Medical Center, Neihu, Taipei, Taiwan
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Ritter CS, Slatopolsky E, Santoro S, Brown AJ. Parathyroid cells cultured in collagen matrix retain calcium responsiveness: importance of three-dimensional tissue architecture. J Bone Miner Res 2004; 19:491-8. [PMID: 15040838 DOI: 10.1359/jbmr.2004.19.3.491] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2003] [Revised: 10/21/2003] [Accepted: 10/21/2003] [Indexed: 11/18/2022]
Abstract
UNLABELLED Primary cultures of bovine parathyroid cells rapidly lose calcium responsiveness. Here, we show that bovine parathyroid cells grown in collagen coalesce into an organoid ("pseudogland") with stable calcium responsiveness. These findings also illustrate the importance of 3-D cellular architecture in parathyroid gland function. INTRODUCTION The ability of extracellular calcium to suppress parathyroid hormone (PTH) secretion is quickly lost in primary monolayer cultures of bovine parathyroid cells. This has been attributed to a decrease in the expression of the cell surface calcium-sensing receptor (CaR), but other factors, including normal cell-to-cell interaction, may be critical. Here we describe a novel system for culturing bovine parathyroid cells that promotes re-formation of a three-dimensional (3-D) cellular architecture and re-establishment of calcium responsiveness. MATERIALS AND METHODS Dispersed bovine parathyroid cells were cultured as monolayers or were mixed with type I collagen and placed in culture plates. CaR mRNA and the calcium regulation of PTH secretion were measured over a period of several weeks in parathyroid cells cultured both in collagen matrix and as monolayers. Calcium regulation of PTH mRNA was also investigated. RESULTS AND CONCLUSIONS Within 1-2 weeks in collagen culture, parathyroid cells coalesced into a small mass approximately 1-2 mm in size (referred to as a pseudogland). Suppression of PTH secretion by high calcium was blunted at 1 day in collagen, but returned within 1 week, and was retained through 3 weeks; the calcium set point (1.05 +/- 0.04 mM) was similar to that reported for freshly dispersed cells. PTH mRNA was also suppressed by increasing extracellular calcium. CaR mRNA expression was decreased at 1 day in collagen and increased with time in culture, although never reaching the level found in dispersed cells. In bovine parathyroid cells cultured as monolayers, however, suppression of PTH by calcium was observed only at day 1 in culture. CaR mRNA content fell by 70% at day 1 but remained stable thereafter. Thus, a total loss of calcium responsiveness in monolayers was observed despite significant residual expression of CaR, suggesting that loss of the calcium response cannot be attributed solely to decreased CaR. In summary, the pseudogland model illustrates the importance of the 3-D cellular architecture in parathyroid gland function and provides a useful model in which to investigate calcium-mediated control of parathyroid gland functions, especially those requiring extended treatment.
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Affiliation(s)
- Cynthia S Ritter
- Renal Division, Washington University School of Medicine, St Louis, Missouri 63110, USA
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Lopez I, Aguilera-Tejero E, Felsenfeld AJ, Estepa JC, Rodriguez M. Direct effect of acute metabolic and respiratory acidosis on parathyroid hormone secretion in the dog. J Bone Miner Res 2002; 17:1691-700. [PMID: 12211440 DOI: 10.1359/jbmr.2002.17.9.1691] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Because both metabolic (Met Acid) and respiratory acidosis (Resp Acid) have diverse effects on mineral metabolism, it has been difficult to establish whether acidosis directly affects parathyroid hormone (PTH) secretion. Our goal was to determine whether acute Met Acid and Resp Acid directly affected PTH secretion. Three groups of dogs were studied: control, acute Met Acid induced by HCl infusion, and acute Resp Acid induced by hypoventilation. EDTA was infused to prevent acidosis-induced increases in ionized calcium, but more EDTA was needed in Met Acid than in Resp Acid. The PTH response to EDTA-induced hypocalcemia was evaluated also. Magnesium needed to be infused in groups receiving EDTA to prevent hypomagnesemia. The half-life of intact PTH (iPTH) was determined during hypocalcemia when PTH was measured after parathyroidectomy. During normocalcemia, PTH values were greater (p < 0.05) in Met Acid (92 +/- 19 pg/ml) and Resp Acid (77 +/- 22 pg/ml) than in controls (27 +/- 5 pg/ml); the respective pH values were 7.23 +/- 0.01, 7.24 +/- 0.01, and 7.39 +/- 0.02. The maximal PTH response to hypocalcemia was greater (p < 0.05) in Met Acid (443 +/- 54 pg/ml) than in Resp Acid (267 +/- 37 pg/ml) and controls (262 +/- 48 pg/ml). The half-life of PTH was greater (p < 0.05) in Met Acid than in controls, but the PTH secretion rate also was greater (p < 0.05) in Met Acid than in the other two groups. In conclusion, (1) both acute Met Acid and Resp Acid increase PTH secretion when the ionized calcium concentration is normal; (2) acute Met Acid may increase the bone efflux of calcium more than Resp Acid; (3) acute Met Acid acts as a secretogogue for PTH secretion because it enhances the maximal PTH response to hypocalcemia.
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Affiliation(s)
- Ignacio Lopez
- Departamento de Medicina y Cirugía Animal, Universidad de Córdoba, Spain
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De Cristofaro V, Colturi C, Masa A, Comelli M, Pedrini LA. Rate dependence of acute PTH release and association between basal plasma calcium and set point of calcium-PTH curve in dialysis patients. Nephrol Dial Transplant 2001; 16:1214-21. [PMID: 11390723 DOI: 10.1093/ndt/16.6.1214] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND In vivo, the control of calcium-mediated acute PTH release during induced hypo- or hypercalcaemia is linked not only to plasma calcium concentration per se but also to the rate and direction of calcium change. In fact, during induced hypocalcaemia, the predominant mechanism that causes PTH to be released is the reduction of plasma Ca(2+) irrespective of the absolute starting concentration of ionized calcium. This mechanism, which is rate-dependent and even activated in conditions of hypercalcaemia, may be involved in the association, reported in several papers, between the basal Ca(2+) and the set point of the calcium-PTH curve. METHODS The calcium-PTH relationship was studied in 12 dialysis patients under conditions of induced low and high predialysis plasma Ca(2+). At each level of basal Ca(2+), dynamic tests were conducted using two methodological approaches. In method A patients underwent low (0.5 mmol/l) calcium dialysis in the stimulation test and high (2 mmol/l) calcium dialysis in the inhibition test, while the dialysate calcium (CaD) was kept constant during each test. In this way a higher but variable rate of change in plasma Ca(2+) was achieved. In method B, CaD was progressively decreased (stimulation test) and increased (inhibition test) during the tests in order to obtain a lower but more constant rate of change in plasma Ca(2+). Consequently, for each patient, four calcium-PTH curves were produced: low basal Ca(2+) with methods A and B, and high basal Ca(2+) with methods A and B. RESULTS Basal plasma Ca(2+) was similar in A and B at low (1.16+/-0.02 vs 1.15+/-0.02 mmol/l) and high (1.25+/-0.02 vs 1.26+/-0.02 mmol/l) basal plasma Ca(2+). The set point was higher in A than in B both at low (1.12+/-0.02 vs 1.10+/-0.02 mmol/l, P=0.01) and high (1.20+/-0.02 vs 1.16+/-0.02 mmol/l, P=0.03) basal Ca(2+) as was the slope (542+/-41 vs 426+/-44%/mmol, P=0.02; 615+/-73 vs 389+/-25%/mmol, P=0.01). No significant difference was found between A and B as regards minimal PTH and plasma Ca(2+) at minimal PTH (Camin) in both calcaemic states. Maximal PTH was slightly higher in B at low (510+/-97 vs 548+/-107 pg/ml, P=NS) and high basal plasma Ca(2+) (410+/-97 vs 464+/-108 pg/ml, P=0.02). Plasma calcium at maximal PTH (Camax) was significantly higher in A (1.1+/-0.03 vs 0.99+/-0.02 mmol/l, P=0.001) at high basal plasma Ca(2+). The set point was strictly related to basal plasma Ca(2+) in both methods, but the slope of the linear regression was significantly steeper with method A. The set point was predicted to increase by 0.881 (CI 0.772-0.990) mmol/l for each mmol/l of increase in basal plasma Ca(2+) with method A and by 0.641 (CI 0.546-0.737) mmol/l for each mmol/l of increase in basal plasma Ca(2+) with method B. CONCLUSIONS (i) Higher and variable rates of change in plasma Ca(2+) produce a higher set point value and a steeper slope of the calcium-PTH curve when compared to lower and more constant rates of calcium change. (ii) The different slope of the linear correlations between basal plasma Ca(2+) and set point in the two methods suggests that the rate-dependent mechanism of acute PTH release plays a significant role in the association between set point and basal plasma Ca(2+). (iii) The significance of the set point is questionable when the calcium-PTH curve is carried out in vivo.
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Affiliation(s)
- V De Cristofaro
- Departments of Nephrology and Dialysis, Hospital of Sondrio, Via Stelvio 25, I-23100 Sondrio, Italy
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Jara A, Chacón C, Valdivieso A, Aris L, Jalil R, Felsenfeld AJ. Effect of calcitriol treatment and withdrawal on hyperparathyroidism in haemodialysis patients with hypocalcaemia. Nephrol Dial Transplant 2001; 16:1009-16. [PMID: 11328908 DOI: 10.1093/ndt/16.5.1009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Calcitriol is used to treat secondary hyperparathyroidism in dialysis patients. For similarly elevated parathyroid hormone (PTH) levels, the PTH response to calcitriol treatment is believed to be better in hypocalcaemic dialysis patients than in dialysis patients with higher serum calcium values. Furthermore, few studies have evaluated the rapidity of the rebound in serum PTH values after prolonged treatment with calcitriol. Our goal was to evaluate (i) the PTH response to calcitriol treatment in hypocalcaemic haemodialysis patients, (ii) the rapidity of rebound in PTH after calcitriol treatment was stopped, and (iii) whether the effect of calcitriol treatment on PTH levels could be separated from those produced by changes in serum calcium and phosphate values. METHODS Eight haemodialysis patients (29+/-3 years) with hypocalcaemia and hyperparathyroidism were treated thrice weekly with 2 microg of intravenous calcitriol and were dialysed with a 3.5 mEq/l calcium dialysate. Parathyroid function (PTH-calcium curve) was determined before and after 30 weeks of calcitriol treatment and 15 weeks after calcitriol treatment was stopped. RESULTS Pretreatment PTH and ionized calcium values were 907+/-127 pg/ml and 3.89+/-0.12 mg/dl (normal, 4.52+/-0.07 mg/dl). During calcitriol treatment, one patient did not respond, but basal (predialysis) PTH values in the other seven patients decreased from 846+/-129 to 72+/-12 pg/ml, P<0.001 and in all seven patients, the decrease exceeded 85%. During the 15 weeks after calcitriol treatment was stopped, a slow rebound in basal PTH values in the seven patients was observed, 72+/-12 to 375+/-44 pg/ml. Covariance analysis was used to evaluate the three tests of parathyroid function (0, 30, and 45 weeks), and showed that calcitriol treatment was associated with reductions in maximal PTH values while reductions in basal PTH were affected by ionized calcium and serum phosphate. The basal/maximal PTH ratio and the set point of calcium were associated with changes in ionized calcium. CONCLUSIONS In haemodialysis patients with hypocalcaemia, (i) moderate to severe hyperparathyroidism responded well to treatment with calcitriol, (ii) reductions in maximal PTH were calcitriol dependent while reductions in basal PTH were affected by the ionized calcium and serum phosphate concentrations, (iii) changes in the basal/maximal PTH ratio and the set point of calcium were calcium dependent, and (iv) the delayed rebound in basal PTH levels after withdrawal of calcitriol treatment may have been due to the long duration of treatment and the marked PTH suppression during treatment.
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Affiliation(s)
- A Jara
- Department of Nephrology, Hospital Clinico, Pontificia Universidad Catolica de Chile, Marcoleta 345, Santiago, Chile
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47
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Jara A, González S, Felsenfeld AJ, Chacón C, Valdivieso A, Jalil R, Chuaqui B. Failure of high doses of calcitriol and hypercalcaemia to induce apoptosis in hyperplastic parathyroid glands of azotaemic rats. Nephrol Dial Transplant 2001; 16:506-12. [PMID: 11239023 DOI: 10.1093/ndt/16.3.506] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Whether calcitriol administration, which is used to treat secondary hyperparathyroidism in dialysis patients, induces regression of parathyroid-gland hyperplasia remains a subject of interest and debate. If regression of the parathyroid gland were to occur, the presumed mechanism would be apoptosis. However, information on whether high doses of calcitriol can induce apoptosis of parathyroid cells in hyperplastic parathyroid glands is lacking. Consequently, high doses of calcitriol were given to azotaemic rats and the parathyroid glands were evaluated for apoptosis. METHODS Rats were either sham-operated (two groups) or underwent a two-stage 5/6 nephrectomy (three groups). For the first 4 weeks, all rats were given a high (1.2%) phosphorus (P) diet to stimulate parathyroid gland growth and then were changed to a normal (0.6%) P diet for 2 weeks. At week 7, three of the five groups were given high doses of calcitriol (500 pmol/100 g body weight) intraperitoneally every 24 h during 72 h before sacrifice. The five groups during week 7 were: (i) normal renal function (NRF)+0.6% P diet; (ii) NRF+0.6% P+calcitriol; (iii) renal failure (RF)+0.6% P; (iv) RF+1.2% P+calcitriol; and (v) RF+0.6% P+calcitriol. Parathyroid glands were removed at sacrifice and the TUNEL stain was performed to detect apoptosis. RESULTS At sacrifice, the respective serum calcium values in calcitriol-treated groups (groups 2, 4, and 5) were 15.52+/-0.26, 13.41+/-0.39 and 15.12+/-0.32 mg/dl. In group 3, PTH was 178+/-42 pg/ml, but in calcitriol-treated groups, PTH values were suppressed, 8+/-1 (group 2), 12+/-2 (group 4), and 7+/-1 pg/ml (group 5). Despite, the severe hypercalcaemia and marked PTH suppression in calcitriol-treated groups, the percentage of apoptotic cells in the parathyroid glands was very low (range 0.08+/-0.04 to 0.25+/-0.20%) and not different among the five groups. CONCLUSIONS We found no evidence in hyperplastic parathyroid glands that apoptosis could be induced in azotaemic rats by the combination of high doses of calcitriol and severe hypercalcaemia despite the marked reduction in PTH levels that was observed.
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Affiliation(s)
- A Jara
- Department of Nephrology, Pontificia Universidad Católica de Chile, Santiago, Chile
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Affiliation(s)
- S J Marx
- Metabolic Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892-1802, USA.
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