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Hanna RM, Ahdoot RS, Kalantar-Zadeh K, Ghobry L, Kurtz I. Calcium Transport in the Kidney and Disease Processes. Front Endocrinol (Lausanne) 2021; 12:762130. [PMID: 35299844 PMCID: PMC8922474 DOI: 10.3389/fendo.2021.762130] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Accepted: 11/25/2021] [Indexed: 11/25/2022] Open
Abstract
Calcium is a key ion involved in cardiac and skeletal muscle contractility, nerve function, and skeletal structure. Global calcium balance is affected by parathyroid hormone and vitamin D, and calcium is shuttled between the extracellular space and the bone matrix compartment dynamically. The kidney plays an important role in whole-body calcium balance. Abnormalities in the kidney transport proteins alter the renal excretion of calcium. Various hormonal and regulatory pathways have evolved that regulate the renal handling of calcium to maintain the serum calcium within defined limits despite dynamic changes in dietary calcium intake. Dysregulation of renal calcium transport can occur pharmacologically, hormonally, and via genetic mutations in key proteins in various nephron segments resulting in several disease processes. This review focuses on the regulation transport of calcium in the nephron. Genetic diseases affecting the renal handling of calcium that can potentially lead to changes in the serum calcium concentration are reviewed.
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Affiliation(s)
- Ramy M. Hanna
- Division of Nephrology, Department of Medicine, University of California Irvine (UCI) School of Medicine, Orange, CA, United States
- *Correspondence: Ramy M. Hanna,
| | - Rebecca S. Ahdoot
- Division of Nephrology, Department of Medicine, University of California Irvine (UCI) School of Medicine, Orange, CA, United States
| | - Kamyar Kalantar-Zadeh
- Division of Nephrology, Department of Medicine, University of California Irvine (UCI) School of Medicine, Orange, CA, United States
| | - Lena Ghobry
- School of Public Health, University of Pittsburgh, Pittsburgh, PA, United States
| | - Ira Kurtz
- Division of Nephrology, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles (UCLA), Los Angeles, CA, United States
- University of California Los Angeles (UCLA) Brain Research Center, Los Angeles, CA, United States
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Bianchi F, Simoncini C, Brugnoni R, Ricci G, Siciliano G. Neuromuscular tetanic hyperexcitability syndrome associated to a heterozygous Kv1.1 N255D mutation with normal serum magnesium levels. ACTA MYOLOGICA : MYOPATHIES AND CARDIOMYOPATHIES : OFFICIAL JOURNAL OF THE MEDITERRANEAN SOCIETY OF MYOLOGY 2020; 39:36-39. [PMID: 32607479 PMCID: PMC7315896 DOI: 10.36185/2532-1900-007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 03/09/2020] [Indexed: 06/11/2023]
Abstract
Mutations of the main voltage-gated K channel members Kv1.1 are linked to several clinical conditions, such as periodic ataxia type 1, myokymia and seizure disorders. Due to their role in active magnesium reabsorption through the renal distal convoluted tubule segment, mutations in the KCNA1 gene encoding for Kv1.1 has been associated with hypomagnesemia with myokymia and tetanic crises. Here we describe a case of a young female patient who came to our attention for a history of muscular spasms, tetanic episodes and muscle weakness, initially misdiagnosed for fibromyalgia. After a genetic screening she was found to be carrier of the c.736A > G (p.Asn255Asp) mutation in KCNA1, previously described in a family with autosomal dominant hypomagnesemia with muscular spasms, myokymia and tetanic episodes. However, our patient has always presented normal serum and urinary magnesium values, whereas she was affected by hypocalcemia. Calcium supplementation gave only partial clinical benefit, with an improvement on tetanic episodes yet without a clinical remission of her spasms, whereas magnesium supplementation worsened her muscular symptomatology.
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Affiliation(s)
- Francesca Bianchi
- Department of Clinical and Experimental Medicine, Neurological Clinic, University of Pisa, Italy
| | - Costanza Simoncini
- Department of Clinical and Experimental Medicine, Neurological Clinic, University of Pisa, Italy
| | - Raffaella Brugnoni
- Neurology IV - Neuroimmunology and Neuromuscular Diseases Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Giulia Ricci
- Department of Clinical and Experimental Medicine, Neurological Clinic, University of Pisa, Italy
| | - Gabriele Siciliano
- Department of Clinical and Experimental Medicine, Neurological Clinic, University of Pisa, Italy
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Viering DHHM, de Baaij JHF, Walsh SB, Kleta R, Bockenhauer D. Genetic causes of hypomagnesemia, a clinical overview. Pediatr Nephrol 2017; 32:1123-1135. [PMID: 27234911 PMCID: PMC5440500 DOI: 10.1007/s00467-016-3416-3] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 05/02/2016] [Accepted: 05/04/2016] [Indexed: 12/16/2022]
Abstract
Magnesium is essential to the proper functioning of numerous cellular processes. Magnesium ion (Mg2+) deficits, as reflected in hypomagnesemia, can cause neuromuscular irritability, seizures and cardiac arrhythmias. With normal Mg2+ intake, homeostasis is maintained primarily through the regulated reabsorption of Mg2+ by the thick ascending limb of Henle's loop and distal convoluted tubule of the kidney. Inadequate reabsorption results in renal Mg2+ wasting, as evidenced by an inappropriately high fractional Mg2+ excretion. Familial renal Mg2+ wasting is suggestive of a genetic cause, and subsequent studies in these hypomagnesemic families have revealed over a dozen genes directly or indirectly involved in Mg2+ transport. Those can be classified into four groups: hypercalciuric hypomagnesemias (encompassing mutations in CLDN16, CLDN19, CASR, CLCNKB), Gitelman-like hypomagnesemias (CLCNKB, SLC12A3, BSND, KCNJ10, FYXD2, HNF1B, PCBD1), mitochondrial hypomagnesemias (SARS2, MT-TI, Kearns-Sayre syndrome) and other hypomagnesemias (TRPM6, CNMM2, EGF, EGFR, KCNA1, FAM111A). Although identification of these genes has not yet changed treatment, which remains Mg2+ supplementation, it has contributed enormously to our understanding of Mg2+ transport and renal function. In this review, we discuss general mechanisms and symptoms of genetic causes of hypomagnesemia as well as the specific molecular mechanisms and clinical phenotypes associated with each syndrome.
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Affiliation(s)
- Daan H H M Viering
- Centre for Nephrology, University College London, London, UK
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jeroen H F de Baaij
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Stephen B Walsh
- Centre for Nephrology, University College London, London, UK
| | - Robert Kleta
- Centre for Nephrology, University College London, London, UK.
- Paediatric Nephrology, Great Ormond Street Hospital, London, UK.
| | - Detlef Bockenhauer
- Centre for Nephrology, University College London, London, UK
- Paediatric Nephrology, Great Ormond Street Hospital, London, UK
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de Baaij JHF, Hoenderop JGJ, Bindels RJM. Magnesium in man: implications for health and disease. Physiol Rev 2015; 95:1-46. [PMID: 25540137 DOI: 10.1152/physrev.00012.2014] [Citation(s) in RCA: 870] [Impact Index Per Article: 96.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Magnesium (Mg(2+)) is an essential ion to the human body, playing an instrumental role in supporting and sustaining health and life. As the second most abundant intracellular cation after potassium, it is involved in over 600 enzymatic reactions including energy metabolism and protein synthesis. Although Mg(2+) availability has been proven to be disturbed during several clinical situations, serum Mg(2+) values are not generally determined in patients. This review aims to provide an overview of the function of Mg(2+) in human health and disease. In short, Mg(2+) plays an important physiological role particularly in the brain, heart, and skeletal muscles. Moreover, Mg(2+) supplementation has been shown to be beneficial in treatment of, among others, preeclampsia, migraine, depression, coronary artery disease, and asthma. Over the last decade, several hereditary forms of hypomagnesemia have been deciphered, including mutations in transient receptor potential melastatin type 6 (TRPM6), claudin 16, and cyclin M2 (CNNM2). Recently, mutations in Mg(2+) transporter 1 (MagT1) were linked to T-cell deficiency underlining the important role of Mg(2+) in cell viability. Moreover, hypomagnesemia can be the consequence of the use of certain types of drugs, such as diuretics, epidermal growth factor receptor inhibitors, calcineurin inhibitors, and proton pump inhibitors. This review provides an extensive and comprehensive overview of Mg(2+) research over the last few decades, focusing on the regulation of Mg(2+) homeostasis in the intestine, kidney, and bone and disturbances which may result in hypomagnesemia.
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Affiliation(s)
- Jeroen H F de Baaij
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Joost G J Hoenderop
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - René J M Bindels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
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Abstract
The distal convoluted tubule (DCT) is a short nephron segment, interposed between the macula densa and collecting duct. Even though it is short, it plays a key role in regulating extracellular fluid volume and electrolyte homeostasis. DCT cells are rich in mitochondria, and possess the highest density of Na+/K+-ATPase along the nephron, where it is expressed on the highly amplified basolateral membranes. DCT cells are largely water impermeable, and reabsorb sodium and chloride across the apical membrane via electroneurtral pathways. Prominent among this is the thiazide-sensitive sodium chloride cotransporter, target of widely used diuretic drugs. These cells also play a key role in magnesium reabsorption, which occurs predominantly, via a transient receptor potential channel (TRPM6). Human genetic diseases in which DCT function is perturbed have provided critical insights into the physiological role of the DCT, and how transport is regulated. These include Familial Hyperkalemic Hypertension, the salt-wasting diseases Gitelman syndrome and EAST syndrome, and hereditary hypomagnesemias. The DCT is also established as an important target for the hormones angiotensin II and aldosterone; it also appears to respond to sympathetic-nerve stimulation and changes in plasma potassium. Here, we discuss what is currently known about DCT physiology. Early studies that determined transport rates of ions by the DCT are described, as are the channels and transporters expressed along the DCT with the advent of molecular cloning. Regulation of expression and activity of these channels and transporters is also described; particular emphasis is placed on the contribution of genetic forms of DCT dysregulation to our understanding.
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Affiliation(s)
- James A McCormick
- Division of Nephrology & Hypertension, Oregon Health & Science University, & VA Medical Center, Portland, Oregon, United States
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Abstract
Specific channels permit movement of selected ions through cellular membranes, and are of vital importance in a number of physiological processes, particularly in excitable tissues such as nerve and muscle, but also in endocrine organs and in epithelial biology. Disorders of channel proteins are termed channelopathies, and their importance is increasingly recognised within medicine. In the kidney, ion channels have critical roles enabling sodium and potassium reuptake or excretion along the nephron, in magnesium homeostasis, in the control of water reabsorption in the collecting duct, and in determining glomerular permeability. In this review, we assess the channelopathies encountered in each nephron segment, and see how their molecular and genetic characterisation in the past 20–30 years has furthered our understanding of normal kidney physiology and disease processes, aids correct diagnosis and promises future therapeutic opportunities.
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Affiliation(s)
- KW Loudon
- Department of Renal Medicine, Addenbrooke’s Hospital, Cambridge, UK
| | - AC Fry
- Department of Renal Medicine, Addenbrooke’s Hospital, Cambridge, UK
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Kaplinsky C, Alon US. Magnesium homeostasis and hypomagnesemia in children with malignancy. Pediatr Blood Cancer 2013; 60:734-40. [PMID: 23303583 DOI: 10.1002/pbc.24460] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 12/05/2012] [Indexed: 11/07/2022]
Abstract
Hypomagnesemia is not uncommon among children with malignancies. It is especially seen in association with certain medications and can be further complicated by the presence of diarrhea and malnutrition. Severe hypomagnesemia may cause disturbances in the neuromuscular and cardiovascular systems. All patients with hypomagnesemia should be supplemented with the mineral, and urgent treatment is indicated when serum magnesium decreases below 1.0 mg/dl, a level under which symptoms may develop. This review addresses the essentials of magnesium physiology, and pathophysiology of hypomagnesemia, its etiologies, clinical manifestations and ways to treat it, with an emphasis on the child with hematologic/oncologic disorders.
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Affiliation(s)
- Chaim Kaplinsky
- Department of Pediatric Hematology-Oncology, The Edmond and Lily Safra Children's Hospital, The Chaim Sheba Medical Center, Tel Aviv University, Tel Aviv, Israel
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Conotoxins that confer therapeutic possibilities. Mar Drugs 2012; 10:1244-1265. [PMID: 22822370 PMCID: PMC3397437 DOI: 10.3390/md10061244] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Revised: 04/24/2012] [Accepted: 05/24/2012] [Indexed: 12/19/2022] Open
Abstract
Cone snails produce a distinctive repertoire of venom peptides that are used both as a defense mechanism and also to facilitate the immobilization and digestion of prey. These peptides target a wide variety of voltage- and ligand-gated ion channels, which make them an invaluable resource for studying the properties of these ion channels in normal and diseased states, as well as being a collection of compounds of potential pharmacological use in their own right. Examples include the United States Food and Drug Administration (FDA) approved pharmaceutical drug, Ziconotide (Prialt®; Elan Pharmaceuticals, Inc.) that is the synthetic equivalent of the naturally occurring ω-conotoxin MVIIA, whilst several other conotoxins are currently being used as standard research tools and screened as potential therapeutic drugs in pre-clinical or clinical trials. These developments highlight the importance of driving conotoxin-related research. A PubMed query from 1 January 2007 to 31 August 2011 combined with hand-curation of the retrieved articles allowed for the collation of 98 recently identified conotoxins with therapeutic potential which are selectively discussed in this review. Protein sequence similarity analysis tentatively assigned uncharacterized conotoxins to predicted functional classes. Furthermore, conotoxin therapeutic potential for neurodegenerative disorders (NDD) was also inferred.
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Lang F, Huang DY, Vallon V. SGK, renal function and hypertension. J Nephrol 2010; 23 Suppl 16:S124-S129. [PMID: 21170869 PMCID: PMC4026186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/01/2010] [Indexed: 05/30/2023]
Abstract
Serum- and glucocorticoid-inducible kinase 1 (SGK1) is expressed following cell stress and exposure to a variety of hormones including glucocorticoids and mineralocorticoids. It is activated by insulin and growth factors via phosphatidylinositol-3-kinase and the 3-phosphoinositide-dependent kinase PDK1. SGK1 enhances the activity of a variety of ion channels such as ENaC, TRPV5, ROMK, KCNE1/KCNQ1 and ClCKb; carriers such as NHE3, NKCC2, NCC and SGLT1; as well as the Na+/K+-ATPase. SGK1 contributes to Na+ retention and K+ elimination of the kidney as well as mineralocorticoid stimulation of salt appetite. A certain SGK1 gene variant (combined polymorphisms in intron 6 [I6CC] and in exon 8 [E8CC/CT]) is associated with moderately enhanced blood pressure. The SGK1 gene variant has been shown to affect 3%-5% of whites and some 10% of Africans. The gene variant sensitizes the carriers to the hypertensive effects of hyperinsulinemia. Moreover, the SGK1 gene variant is associated with increased body mass index, presumably a result of enhanced SGLT1 activity with accelerated intestinal glucose absorption. Obesity predisposes the carriers of the gene variant to development of type 2 diabetes. Moreover, SGK1 stimulates coagulation. Thus, SGK1 may participate in the pathogenesis of metabolic syndrome or syndrome X, a condition characterized by the coincidence of essential hypertension, procoagulant state, obesity, insulin resistance and hyperinsulinemia.
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Affiliation(s)
- Florian Lang
- Department of Physiology, University of Tuebingen, Tuebingen, Germany.
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