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Magagnoli L, Ciceri P, Cozzolino M. Secondary hyperparathyroidism in chronic kidney disease: pathophysiology, current treatments and investigational drugs. Expert Opin Investig Drugs 2024; 33:775-789. [PMID: 38881200 DOI: 10.1080/13543784.2024.2369307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 06/13/2024] [Indexed: 06/18/2024]
Abstract
INTRODUCTION Secondary hyperparathyroidism (SHPT) is a common complication of chronic kidney disease (CKD). It begins as an adaptive increase in parathyroid hormone levels to prevent calcium and phosphate derangements. Over time, this condition becomes maladaptive and is associated with increased morbidity and mortality. Current therapies encompass phosphate-lowering strategies, vitamin D analogues, calcimimetics and parathyroidectomy. These approaches harbor inherent limitations, stimulating interest in the development of new drugs for SHPT to overcome these limitations and improve survival and quality of life among CKD patients. AREAS COVERED This review delves into the main pathophysiological mechanisms involved in SHPT, alongside the treatment options that are currently available and under active investigation. Data presented herein stem from a comprehensive search conducted across PubMed, Web of Science, ClinicalTrials.gov and International Clinical Trials Registry Platform (ICTRP) spanning from 2000 onwards. EXPERT OPINION The advancements in investigational drugs for SHPT hold significant promise for enhancing treatment efficacy while minimizing side effects associated with conventional therapies. Although several challenges still hinder their adoption in clinical practice, ongoing research will likely continue to expand the available therapeutic options, refine treatment strategies, and tailor them to individual patient profiles.
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Affiliation(s)
- Lorenza Magagnoli
- Department of Health Sciences, University of Milan, IT, Milano, Italy
| | - Paola Ciceri
- Laboratory of Experimental Nephrology, Department of Health Sciences, University of Milan, IT, Milano, Italy
| | - Mario Cozzolino
- Department of Health Sciences, University of Milan, IT, Milano, Italy
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Xiang Z, Wang M, Miao C, Jin D, Wang H. Mechanism of calcitriol regulating parathyroid cells in secondary hyperparathyroidism. Front Pharmacol 2022; 13:1020858. [PMID: 36267284 PMCID: PMC9577402 DOI: 10.3389/fphar.2022.1020858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 09/15/2022] [Indexed: 12/03/2022] Open
Abstract
A common consequence of chronic renal disease is secondary hyperparathyroidism (SHPT) and is closely related to the mortality and morbidity of uremia patients. Secondary hyperparathyroidism (SHPT) is caused by excessive PTH production and release, as well as parathyroid enlargement. At present, the mechanism of cell proliferation in secondary hyperparathyroidism (SHPT) is not completely clear. Decreased expression of the vitamin D receptor (VDR) and calcium-sensing receptor (CaSR), and 1,25(OH)2D3 insufficiency all lead to a decrease in cell proliferation suppression, and activation of multiple pathways is also involved in cell proliferation in renal hyperparathyroidism. The interaction between the parathormone (PTH) and parathyroid hyperplasia and 1,25(OH)2D3 has received considerable attention. 1,25(OH)2D3 is commonly applied in the therapy of renal hyperparathyroidism. It regulates the production of parathormone (PTH) and parathyroid cell proliferation through transcription and post-transcription mechanisms. This article reviews the role of 1,25(OH)2D3 in parathyroid cells in secondary hyperparathyroidism and its current understanding and potential molecular mechanism.
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The Effects of Vitamins and Micronutrients on Helicobacter pylori Pathogenicity, Survival, and Eradication: A Crosstalk between Micronutrients and Immune System. J Immunol Res 2022; 2022:4713684. [PMID: 35340586 PMCID: PMC8942682 DOI: 10.1155/2022/4713684] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 02/19/2022] [Accepted: 02/25/2022] [Indexed: 12/11/2022] Open
Abstract
Helicobacter pylori as a class I carcinogen is correlated with a variety of severe gastroduodenal diseases; therefore, H. pylori eradication has become a priority to prevent gastric carcinogenesis. However, due to the emergence and spread of multidrug and single drug resistance mechanisms in H. pylori, as well as serious side effects of currently used antibiotic interventions, achieving successful H. pylori eradication has become exceedingly difficult. Recent studies expressed the intention of seeking novel strategies to improve H. pylori management and reduce the risk of H. pylori-associated intestinal and extragastrointestinal disorders. For which, vitamin supplementation has been demonstrated in many studies to have a tight interaction with H. pylori infection, either directly through the regulation of the host inflammatory pathways or indirectly by promoting the host immune response. On the other hand, H. pylori infection is reported to result in micronutrient malabsorption or deficiency. Furthermore, serum levels of particular micronutrients, especially vitamin D, are inversely correlated to the risk of H. pylori infection and eradication failure. Accordingly, vitamin supplementation might increase the efficiency of H. pylori eradication and reduce the risk of drug-related adverse effects. Therefore, this review aims at highlighting the regulatory role of micronutrients in H. pylori-induced host immune response and their potential capacity, as intrinsic antioxidants, for reducing oxidative stress and inflammation. We also discuss the uncovered mechanisms underlying the molecular and serological interactions between micronutrients and H. pylori infection to present a perspective for innovative in vitro investigations, as well as novel clinical implications.
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Abstract
Parathyroid hormone is an essential regulator of extracellular calcium and phosphate. PTH enhances calcium reabsorption while inhibiting phosphate reabsorption in the kidneys, increases the synthesis of 1,25-dihydroxyvitamin D, which then increases gastrointestinal absorption of calcium, and increases bone resorption to increase calcium and phosphate. Parathyroid disease can be an isolated endocrine disorder or part of a complex syndrome. Genetic mutations can account for diseases of parathyroid gland formulation, dysregulation of parathyroid hormone synthesis or secretion, and destruction of the parathyroid glands. Over the years, a number of different options are available for the treatment of different types of parathyroid disease. Therapeutic options include surgical removal of hypersecreting parathyroid tissue, administration of parathyroid hormone, vitamin D, activated vitamin D, calcium, phosphate binders, calcium-sensing receptor, and vitamin D receptor activators to name a few. The accurate assessment of parathyroid hormone also provides essential biochemical information to properly diagnose parathyroid disease. Currently available immunoassays may overestimate or underestimate bioactive parathyroid hormone because of interferences from truncated parathyroid hormone fragments, phosphorylation of parathyroid hormone, and oxidation of amino acids of parathyroid hormone.
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Affiliation(s)
- Edward Ki Yun Leung
- Department of Pathology and Laboratory Medicine, Children's Hospital Los Angeles, Los Angeles, CA, United States; Department of Pathology, Keck School of Medicine of University of Southern California, Los Angeles, CA, United States.
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Abstract
Parathyroid hormone (PTH) exerts both anabolic and catabolic actions on bone,depending on the duration and periodicity of exposure. Hypoparathyroidism is defined by inadequate production of PTH in the presence oflow serum calcium. In hypoparathyroidism it has been reported an increase in corticaland trabecular bone mass, but it is still unknown if these quantitative variations maybe accompanied by qualitative ones and increased bone strength. Despite the extensive data available on the effects of hypoparathyroidism on bone, itseffect on the hard end point in this area which is the risk of fractures still remainsunresolved and highly debated. As a matter of fact no previous review has focused onthis relevant clinical topic. This review will deal with the various aspects of bone metabolism (turn-over,density, quality) in hypoparathyroidism, focusing on the few data available on therisk of fracture and in particular of morphometric vertebral fractures, the emerging way to assess actual skeletal fragility particularly in secondary forms of osteoporosis.
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Affiliation(s)
| | | | | | - Andrea Giustina
- San Raffaele Vita-Salute University Via Olgettina, Milano, Italy.
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Abstract
Parathyroid hormone (PTH) is the major secretory product of the parathyroid glands, and in hypocalcemic conditions, can enhance renal calcium reabsorption, increase active vitamin D production to increase intestinal calcium absorption, and mobilize calcium from bone by increasing turnover, mainly but not exclusively in cortical bone. PTH has therefore found clinical use as replacement therapy in hypoparathyroidism. PTH also may have a physiologic role in augmenting bone formation, particularly in trabecular and to some extent in cortical bone. This action has been applied to the clinic to provide anabolic therapy for osteoporosis.
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Affiliation(s)
- David Goltzman
- Department of Medicine and Research Institute of the McGill University Health Centre, 1001 Decarie Boulevard, Montreal, Quebec H4A 3J1, Canada; Departments of Medicine and of Physiology, McGill University, 845 Sherbrooke St West, Montreal, Quebec H3A 0B9, Canada.
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Cozzolino M, Pasho S, Fallabrino G, Olivi L, Gallieni M, Brancaccio D. Pathogenesis of Secondary Hyperparathyroidism. Int J Artif Organs 2018; 32:75-80. [DOI: 10.1177/039139880903200203] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Chronic renal failure is the primary cause of secondary hyperparathyroidism (SHPT). Patients with mineral metabolism disorders commonly present with low serum calcium levels, hyperphosphatemia, and calcitriol deficiency. In normal renal function subjects, parathyroid cells have a low turnover and rarely undergo mitoses. In uremic conditions, however, parathyroid glands become hyperplasic and leave quiescence. During the last ten years, new molecular mechanisms have been investigated to better understand the pathogenesis of SHPT: the emerging role of the Calcium Sensing Receptor (CaSR); the importance of the parathyroid expression of the Vitamin D receptor (VDR); the growing evidence on the central role of the Fibroblast Growth Factor 23 (FGF-23). In contrast, the discovery of a parathyroid phosphate sensor or receptor has yet to be made.
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Affiliation(s)
- Mario Cozzolino
- Renal Division, San Paolo Hospital, University of Milan, Milan - Italy
| | - Sabina Pasho
- Renal Division, San Paolo Hospital, University of Milan, Milan - Italy
| | | | - Laura Olivi
- Renal Division, San Paolo Hospital, University of Milan, Milan - Italy
| | - Maurizio Gallieni
- Renal Division, San Paolo Hospital, University of Milan, Milan - Italy
| | - Diego Brancaccio
- Renal Division, San Paolo Hospital, University of Milan, Milan - Italy
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Gallieni M, Cozzolino M, Fallabrino G, Pasho S, Olivi L, Brancaccio D. Vitamin D: Physiology and Pathophysiology. Int J Artif Organs 2018; 32:87-94. [DOI: 10.1177/039139880903200205] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Although vitamin D was initially considered a nutrient, it has been recognized that the molecules derived from vitamin D metabolism are best considered as a complex endocrine system. In this review article we summarize the basic concepts regarding vitamin D metabolism, transport, and genomic activity through the vitamin D receptor, facilitating activation or suppression of target genes. We also examine non-genomic actions, biological responses to vitamin D in classic target organs (intestine, bone, kidneys, and parathyroid glands), and in organs and tissues not related to mineral homeostasis.
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Affiliation(s)
- Maurizio Gallieni
- Nephrology and Dialysis Unit, San Paolo Hospital, University of Milan, Milan
| | - Mario Cozzolino
- Nephrology and Dialysis Unit, San Paolo Hospital, University of Milan, Milan
- Chair of Nephrology, Department of Medicine, Surgery and Dentistry, University of Milan - Italy
| | - Giuditta Fallabrino
- Nephrology and Dialysis Unit, San Paolo Hospital, University of Milan, Milan
| | - Sabina Pasho
- Nephrology and Dialysis Unit, San Paolo Hospital, University of Milan, Milan
| | - Laura Olivi
- Nephrology and Dialysis Unit, San Paolo Hospital, University of Milan, Milan
| | - Diego Brancaccio
- Nephrology and Dialysis Unit, San Paolo Hospital, University of Milan, Milan
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Cozzolino M, Brancaccio D. Hyperphosphatemia in Dialysis Patients: The Therapeutic Role of Lanthanum Carbonate. Int J Artif Organs 2018; 30:293-300. [PMID: 17520565 DOI: 10.1177/039139880703000403] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Phosphate overload is a dramatic consequence in end-stage renal disease (ESRD) patients. Recent studies have well documented that abnormalities in mineral and bone metabolism in these patients are associated with increased cardiovascular morbidity and mortality. Elevated serum phosphate and calcium-phosphate product levels play an important role in the pathogenesis of secondary hyperparathyroidism and extra-skeletal calcification in dialysis patients. Furthermore, inorganic phosphate may cause vascular calcification directly through a real “ossification” of the tunica media in the vasculature of ESRD patients. The “classical” treatment of secondary hyperparathyroidism and hyperphosphatemia in ESRD patients consists of either calcium- or aluminum-based phosphate binders and calcitriol administration. Unfortunately, this “old generation” therapy is not free of complications. This review paper suggests that new calcium- and aluminum-free phosphate binders, such as lanthanum carbonate, can be used to treat hyperphosphatemia and secondary hyperparathyroidism in ESRD patients.
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Affiliation(s)
- M Cozzolino
- Renal Division, Department of Medicine, Surgery, and Dentistry, San Paolo Hospital, University of Milan, Milan - Italy.
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Galassi A, Cupisti A, Santoro A, Cozzolino M. Phosphate balance in ESRD: diet, dialysis and binders against the low evident masked pool. J Nephrol 2014; 28:415-29. [PMID: 25245472 DOI: 10.1007/s40620-014-0142-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 09/11/2014] [Indexed: 12/11/2022]
Abstract
Phosphate metabolism is crucial in the pathophysiology of secondary hyperparathyroidism and vascular calcification. High phosphate levels have been consistently associated with unfavorable outcomes in dialysis patients, but several limitations are still hampering a resolutive definition of the optimal targets of phosphate serum levels to be achieved in this cohort. Nonetheless, hyperphosphatemia is a late marker of phosphate overload in humans. Clinical nephrologists routinely counteract the positive phosphate balance in dialysis patients through nutritional counseling, stronger phosphate removal by dialysis and prescription of phosphate binders. However, the superiority against placebo of phosphate control by diet, dialysis or binders in terms of survival has never been tested in dedicated randomized controlled trials. The present review discusses this conundrum with particular emphasis on the rationale supporting the value of a simultaneous intervention against phosphate overload in dialysis patients via the improvement of dietary intakes, dialysis efficiency and an individualized choice of phosphate binders.
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Affiliation(s)
- A Galassi
- Department of Medicine, Renal and Dialysis Unit, Desio Hospital, Desio, Italy,
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11
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The parathyroid glands. Mol Oncol 2013. [DOI: 10.1017/cbo9781139046947.066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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12
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Lương KVQ, Nguyễn LTH. The roles of vitamin D in seborrhoeic keratosis: possible genetic and cellular signalling mechanisms. Int J Cosmet Sci 2013; 35:525-31. [DOI: 10.1111/ics.12080] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2013] [Accepted: 07/07/2013] [Indexed: 12/22/2022]
Affiliation(s)
- K. v. q. Lương
- Vietnamese American Medical Research Foundation; 14971 Brookhurst St. Westminster CA 92683 U.S.A
| | - L. T. H. Nguyễn
- Vietnamese American Medical Research Foundation; 14971 Brookhurst St. Westminster CA 92683 U.S.A
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Nemazannikova N, Antonas K, Dass CR. Vitamin D: metabolism, molecular mechanisms, and mutations to malignancies. Mol Carcinog 2013; 53:421-31. [PMID: 23359295 DOI: 10.1002/mc.21999] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Revised: 11/16/2012] [Accepted: 12/12/2012] [Indexed: 01/30/2023]
Abstract
The potential protective effects of vitamin D against cutaneous carcinogenesis are still poorly understood. The inhibition, by vitamin D, of various cancers in in vitro and in vivo models has triggered detailed investigation of vitamin D effects on neoplastic behavior. Recent studies highlight that such neoplastic features as the tumor microenvironment, angiogenesis, DNA mutagenesis, and apoptosis are all connected to vitamin D metabolic pathways. This review discusses these connections. Vitamin D modulation of the cell cycle, DNA repair and apoptosis via its receptors (VDRs) may have a suppressive effect on skin cancer as some studies suggest. The regulation of multiple tumor signaling pathways by vitamin D may have an implication in cutaneous carcinogenesis and tumor progression to malignancy.
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14
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Bienaimé F, Prié D, Friedlander G, Souberbielle JC. Vitamin D metabolism and activity in the parathyroid gland. Mol Cell Endocrinol 2011; 347:30-41. [PMID: 21664247 DOI: 10.1016/j.mce.2011.05.031] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Revised: 05/05/2011] [Accepted: 05/06/2011] [Indexed: 12/21/2022]
Abstract
Parathormone (PTH) and vitamin D are two critical hormonal regulators of calcium homeostasis. An important cross-talk exists between the PTH and vitamin D hormonal systems. PTH enhances vitamin D hydroxylation on carbon 1 in kidney cells thereby allowing the systemic release of 1-25-dihydroxy-vitamin D, which represents the fully active hormone. Conversely, parathyroid gland represents a direct target for vitamin D. Parathyroid cells express the vitamin D receptor and the 1-α-hydroxylase enzyme, which allows the local formation of 1-25-dihydroxy-vitamin D. Because of its potential implication in several diseases, including osteoporosis or chronic kidney disease, the interplay between PTH and vitamin D has received considerable attention these last two decades. The aim of this review is to summarize our current understanding of the molecular basis of vitamin D action and metabolism in parathyroid cells. The potential clinical implications of the recent advances made in this field will also be discussed.
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Affiliation(s)
- Frank Bienaimé
- Service de Physiologie - Explorations Fonctionnelles, Hôpital Necker Enfants Malades, 149 Rue de Sèvres, 75015 Paris, France
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Zhang Q, Qiu J, Li H, Lu Y, Wang X, Yang J, Wang S, Zhang L, Gu Y, Hao CM, Chen J. Cyclooxygenase 2 promotes parathyroid hyperplasia in ESRD. J Am Soc Nephrol 2011; 22:664-72. [PMID: 21335517 DOI: 10.1681/asn.2010060594] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Hyperplasia of the PTG underlies the secondary hyperparathyroidism (SHPT) observed in CKD, but the mechanism underlying this hyperplasia is incompletely understood. Because aberrant cyclooxygenase 2 (COX2) expression promotes epithelial cell proliferation, we examined the effects of COX2 on the parathyroid gland in uremia. In patients with ESRD who underwent parathyroidectomy, clusters of cells within the parathyroid glands had increased COX2 expression. Some COX2-positive cells exhibited two nuclei, consistent with proliferation. Furthermore, nearly 78% of COX2-positive cells expressed proliferating cell nuclear antigen (PCNA). In the 5/6-nephrectomy rat model, rats fed a high-phosphate diet had significantly higher serum PTH levels and larger parathyroid glands than sham-operated rats. Compared with controls, the parathyroid glands of uremic rats exhibited more PCNA-positive cells and greater COX2 expression in the chief cells. Treatment with COX2 inhibitor celecoxib significantly reduced PCNA expression, attenuated serum PTH levels, and reduced the size of the glands. In conclusion, COX2 promotes the pathogenesis of hyperparathyroidism in ESRD, suggesting that inhibiting the COX2 pathway could be a potential therapeutic target.
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Affiliation(s)
- Qian Zhang
- Division of Nephrology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai 200040, People's Republic of China
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Valdivielso JM, Cannata-Andía J, Coll B, Fernández E. A new role for vitamin D receptor activation in chronic kidney disease. Am J Physiol Renal Physiol 2009; 297:F1502-9. [PMID: 19625376 DOI: 10.1152/ajprenal.00130.2009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Vitamin D has proven to be much more than a simple "calcium hormone." The fact that the vitamin D receptor has been found in cells not related to mineral metabolism supports that statement. The interest of nephrologists in vitamin D and its effects beyond mineral metabolism has increased over the last few years, evidencing the importance of this so-called "sunshine hormone." In the present review, we highlight the most recent developments in the traditional use of vitamin D in chronic kidney disease (CKD) patients, namely, the control of secondary hyperparathyroidism (sHPT). Furthermore, we also explore the data available regarding the new possible therapeutic uses of vitamin D for the treatment of other complications present in CKD patients, such as vascular calcification, left ventricular hypertrophy, or proteinuria. Finally, some still scarce but very promising data regarding a possible role of vitamin D in kidney transplant patients also are reviewed. The available data point to a potential beneficial effect of vitamin D in CKD patients beyond the control of mineral metabolism.
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Affiliation(s)
- José M Valdivielso
- Laboratorio de Nefrología Experimental, IRBLLEIDA, Hospital Universitari Arnau de Vilanova, Rovira Roure 80, 25198 Lleida, Spain.
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17
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Goodman WG, Quarles LD. Development and progression of secondary hyperparathyroidism in chronic kidney disease: lessons from molecular genetics. Kidney Int 2008; 74:276-88. [PMID: 17568787 DOI: 10.1038/sj.ki.5002287] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The identification of the calcium-sensing receptor (CaSR) and the clarification of its role as the major regulator of parathyroid gland function have important implications for understanding the pathogenesis and evolution of secondary hyperthyroidism in chronic kidney disease (CKD). Signaling through the CaSR has direct effects on three discrete components of parathyroid gland function, which include parathyroid hormone (PTH) secretion, PTH synthesis, and parathyroid gland hyperplasia. Disturbances in calcium and vitamin D metabolism that arise owing to CKD diminish the level of activation of the CaSR, leading to increases in PTH secretion, PTH synthesis, and parathyroid gland hyperplasia. Each represents a physiological adaptive response by the parathyroid glands to maintain plasma calcium homeostasis. Studies of genetically modified mice indicate that signal transduction via the CaSR is a key determinant of parathyroid cell proliferation and parathyroid gland hyperplasia. Because enlargement of the parathyroid glands has important implications for disease progression and disease severity, it is possible that clinical management strategies that maintain adequate calcium-dependent signaling through the CaSR will ultimately prove useful in diminishing parathyroid gland hyperplasia and in modifying disease progression.
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Affiliation(s)
- William G Goodman
- Division of Nephrology, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, USA.
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18
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Cozzolino M, Brancaccio D. Emerging role for the vitamin D receptor activator (VDRA), paricalcitol, in the treatment of secondary hyperparathyroidism. Expert Opin Pharmacother 2008; 9:947-54. [DOI: 10.1517/14656566.9.6.947] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Riccardi D, Martin D. The role of the calcium-sensing receptor in the pathophysiology of secondary hyperparathyroidism. NDT Plus 2008; 1:i7-i11. [PMID: 25983956 PMCID: PMC4421157 DOI: 10.1093/ndtplus/sfm038] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2007] [Accepted: 09/10/2007] [Indexed: 11/21/2022] Open
Abstract
The calcium-sensing receptor (CaR), a seven-transmembrane domain receptor belonging to the G protein-coupled receptor family, is responsible for calcium-mediated signalling initiated at the surface of parathyroid cells that controls the synthesis and secretion of parathyroid hormone (PTH). Expression of the CaR is downregulated in animal models of uraemia and in patients with secondary hyperparathyroidism (SHPT). Cinacalcet is a type II calcimimetic agent that acts as an allosteric modulator of CaR signalling. It has been shown in clinical studies to improve control of serum PTH levels and in preclinical studies to attenuate SHPT disease progression and parathyroid hyperplasia. Cinacalcet represents the first of this novel class of agents and a major advance in the treatment of SHPT.
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Abstract
Chronic kidney disease mineral-bone disorder (CKD-MBD) is a systemic disorder of abnormal serum levels of mineral-related biochemistries, abnormal bone, and extraskeletal calcification. Although we have gained understanding on how these components are interrelated, our therapeutic tools remain focused on only one aspect of CKD-MBD at a time. However, the management of these disorders is also interrelated; treatments may help one aspect of the disorder but cause or accelerate another. As such, management remains a major challenge to nephrologists and requires balancing risk and benefit of the various available therapies. Our challenge for the decade ahead is to determine which combinations of therapy can be used safely together to prevent morbidity and mortality in CKD. Furthermore, the pathophysiology that sets these events into motion begins well before the onset of ESRD. Future therapies and guidelines should, therefore, also emphasize the need for earlier detection and management of CKD, shaped by the results of valid clinical trials.
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Affiliation(s)
- Stephen Z Fadem
- Baylor College of Medicine, Division of Nephrology, Houston, TX, USA.
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Dusso AS, Sato T, Arcidiacono MV, Alvarez-Hernandez D, Yang J, Gonzalez-Suarez I, Tominaga Y, Slatopolsky E. Pathogenic mechanisms for parathyroid hyperplasia. Kidney Int 2006:S8-11. [PMID: 16810310 DOI: 10.1038/sj.ki.5001595] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Parathyroid hyperplasia is the cause of parathyroid gland enlargement in kidney disease (KD). Hypocalcemia, hyperphosphatemia, and vitamin D deficiency are critical contributors to the worsening of the hyperplastic parathyroid growth induced by KD. Reproduction of the features of human KD in the 5/6 nephrectomized rat model has shown that 80% of the mitogenic signals induced by KD in parathyroid cells that are aggravated by either high phosphate (P) or low calcium (Ca) diets occurred within 5 days after the onset of KD. Enhanced parathyroid expression of the potent growth promoter transforming growth factor alpha (TGFalpha) and its receptor, the epidermal growth factor receptor (EGFR), was identified as the main cause of parathyroid hyperplasia in experimental KD. Indeed, administration of highly specific EGFR-tyrosine kinase inhibitors (TKI), which block downstream signaling from TGFalpha-activated EGFR, completely prevented high P- and low Ca-induced parathyroid hyperplasia in early KD, as well as the severe progression of high P-induced parathyroid growth in established secondary hyperparathyroidism, the latter characterized by marked TGFalpha and EGFR overexpression in the parathyroid glands. More importantly, the suppression of signals downstream from TGFalpha binding to EGFR with EGFR-TKI treatment also revealed that TGFalpha self-upregulation in the parathyroid glands is the main determinant of the severity of the hyperplastic growth, and that enhanced TGFalpha activation of EGFR mediates the reduction in parathyroid vitamin D receptor levels thereby causing resistance to both the antiproliferative and parathyroid hormone-suppressive properties of calcitriol therapy.
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Affiliation(s)
- A S Dusso
- Renal Division, Washington University School of Medicine, St Louis, Missouri 63110, USA.
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Abstract
Activated vitamin D continues to be the major treatment for suppressing parathyroid hormone (PTH) levels in dialysis patients who have secondary hyperparathyroidism. Active vitamin D compounds are distinguished by their ability to bind with high affinity to vitamin D receptors (VDRs) not only in the parathyroid glands, but in cells throughout the body. Because of recent data showing that pulsatile, intravenous vitamin D treatment (calcitriol or paricalcitol) confers a survival advantage in the dialysis population, there is new interest in understanding the systemic effects of VDR activation, particularly in the predialysis stages of chronic kidney disease (CKD), where high mortality rates from cardiovascular disease have recently been documented. Previous underutilization of calcitriol treatment to control PTH levels in stages 3 and 4 CKD was often due to concerns about its potential for accelerating the progression of CKD as a consequence of hypercalcemia, hypercalciuria, or hyperphosphatemia. Vitamin D analogs with selective VDR activity (such as paricalcitol) have great potential for preventing parathyroid hyperplasia and bone loss in early CKD without adversely affecting kidney function. Whether they also reduce cardiovascular morbidity and mortality in early CKD, as they appear to do in dialysis patients, remains to be determined.
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Affiliation(s)
- Dennis L Andress
- Department of Medicine, VA Puget Sound Health Care System and Department of Medicine, University of Washington, Seattle, Washington 98108, USA.
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