Andrzej Chairmen

Mazur

Michael J Lenardo

Federica I Wolf

Jeroen H F De Baaij

Vladimir Chubanov

Wei Yang

Evan C Ray

Donnie Cameron

Laura Locatelli

Andrea Chairmen

Pahoa, HI, USA Rhian M Rosanoff

( Touyz

UK Francisco Glasgow

Rios

Qi Dai

Rhian M Touyz

Zhi-Guo Zou

Fu-Chou Cheng

Andrea M P Romani

Samuel C Dudley

Yiqing Song

Stella Lucia Volpe

Connie M Weaver

Sofya P Konchits

Roger Clemens

Linda Van Horn

Andrea Rosanoff

Andrzej Mazur

Stefano Iotti

Bogdan Milojkovic

William B Weglicki

Daniela Buccella

Andrea Fleig

Susanna Zierler

Walther Straub

Gerhard Sponder

Michel L Tremblay

Thomas Gudermann

J Ashot Kozak

Sara Castiglioni

Charles Sfeir

Reid Gilmore

Mathieu Gautier

Louise Chairmen

Leeds, UK Gisèle Dye

Pickering

Gisèle Pickering

Kotaro Oka

Louise Dye

Igor Iezhitsa

Romeo Valentina

Ailsa A Welch

Jeanette Am Maier

Valentina Trapani

I Tong Mak

Klaus Kisters

Uwe Gröber

A Catalano

D Chilà

F Bellone

N Morabito

S Loddo

S Benvenga

F Corica

Sayuri Suzuki

Reinhold Penner

S Jurek

M A Sandhu

S Trappe

M Kolisek

J R Aschenbach

Ph.D Rebecca Costello

Forrest Nielsen

Ph. D Michael R Plesset

Ronald Elin

Branimir Radosavljević

Svetlana Ignjatović

Emily Young

Ph. D Bernadette P Marriott

Kidney, the key organ of magnesium homeostasis

Keywords: magnesium ratios, vitamin D synthesis 40 Oral Communications Magnesium, skeletal muscle health, sarcopenia, osteoporosis and fracture risk

The anticancer EGFR

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Biographical Sketch

Enzyme catalysis has been studied for over a century. How it actually occurs has not been visualized until recently. By combining in crystallo catalysis with X-ray diffraction analysis of reaction intermediates, we have observed the processes of DNA synthesis and RNA degradation at unprecedented atomic details. Contrary to the canonical view that enzyme-substrate, transition state, and enzyme-product states have identical atomic composition and catalysis occurs by a two-Mg 2+ -ion mechanism with rearranging of electrons, protons and electrostatic charges, we have discovered that it is essential for enzyme-substrate complexes to capture a third Mg 2+ ion en route to product formation. Unlike the canonical two metal ions, which are coordinated by DNA polymerases and nucleases, this third metal ion is free of enzyme coordination and is liganded by nucleic acid substrate/product only. Its location between the α-and β-phosphates of dNTP in the case of DNA synthesis suggests that the third metal ion may drive phosphoryl-transfer by breaking the existing phosphodiester bond in dNTP. In contrast, during RNA degradation, the transiently bound third Mg 2+ ion appears to activate the nucleophilic water. Experimental data indicate that binding of the third metal ion may be the rate-limiting step in DNA synthesis, and the free energy associated with metal-ion binding may overcome the activation barrier to the DNA synthesis reaction.

References: 1. Gao, Y. & Yang, W. (2016) Capture of a third Mg 2+ is essential for catalyzing DNA synthesis, Science, 352, 1334-1337. 2. Samara, N. & Yang, W. (2018) Cation trafficking propels RNA hydrolysis, NSMB, 25, 715-721. 3. Nakamura, T., Zhao, Y., Yamagata, Y., Hua, Y.J. & Yang, W. (2012) Watching DNA polymerase make a phosphodiester bond. Nature,487,[196][197][198][199][200][201].

Wei Yang

Laboratory of Molecular Biology, NIDDK, National Institutes of Health, USA Intestine, the entrance door of magnesium into the body Group Leader, Walther-Straub Institute of Pharmacology and Toxicology, LMU Munich, Germany. Studies of my group are focused on TRPM6 and TRPM7, bifunctional proteins comprising a channel segment linked to an α-type protein kinase. Loss-of-function mutations in the human TRPM6 gene cause an autosomal recessive disorder, hypomagnesemia 1, intestinal (HOMG1) also called hypomagnesemia with secondary hypocalcemia (HSH). Mechanistically, the regulation of Mg 2+ homeostasis by these two channel kinases and the pathophysiological consequences of TRPM6 mutations are only poorly understood. Therefore, the major goal of our studies is to attain mechanistic knowledge about the physiological and pathophysiological roles of kinase-coupled channels using gene-modified mice and primary cells derived from TRPM6-and TRPM7-deficient animals. Contact: vladimir.chubanov@lrz.uni-muenchen.de

Biographical Sketch

Mg 2+ regulates many physiological processes and signalling pathways. However, little is known about the mechanisms underlying the organismal balance of Mg 2+ . Approximately 10 plasma membrane Mg 2+ channels have been proposed including TRPM6 and TRPM7. TRPM6 and TRPM7 are bifunctional proteins comprising a TRP channel segment linked to an α-type protein kinase. Recently, we have uncovered the molecular and organismal roles of TRPM6 in mice. We showed that TRPM6 activity in the placenta and yolk sac is essential for embryonic development. In adult mice, TRPM6 is required in the intestine to maintain organismal Mg 2+ balance, but is dispensable in the kidney. In our follow-up studies, we aimed to define a role of TRPM7 in adult mice. The function of TRPM7 was assessed by single channel analysis of TRPM7, phenotyping of TRPM7-deficient cells in conjunction with metabolic profiling of mice carrying intestine-and kidneys-restricted null mutations in Trpm7, and animals with a global 'kinase-dead' point mutation in the gene. Overall, our study offers a new paradigm for the physiological role of TRPM7.

Vladimir Chubanov

Walther-Straub Institute of Pharmacology and Toxicology, LMU Munich, Munich, Germany Jeroen H.F. de Baaij Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands Kidney, the key organ of magnesium homeostasis Jeroen de Baaij is a physiologist interested in the molecular and genetic origin of renal electrolyte disorders, including hypomagnesemia. His research focusses on the identification and characterization of new genes involved in renal magnesium reabsorption. He identifies the genetic origin of disease in patients with magnesium disturbances by next generation sequencing techniques. Using a wide range of molecular, cellular and physiological techniques, he examines new genes or new regulatory pathways in magnesium (re)absorption in the kidney. Supported by NWO Rubicon and Veni Grants and a Dutch Kidney Foundation Kolff Grant, his team is also examining the role of magnesium in the prevention of cardiovascular complications and in the development of the type 2 diabetes mellitus. Contact: Jeroen.deBaaij@radboudumc.nl

Biographical Sketch

Purpose: 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.

Materials and methods:

This presentation aims to provide an overview of the regulation of Mg 2+ in human health and disease.

Results: Over the last decade, several hereditary forms of renal causes of hypomagnesemia have been deciphered, including mutations in transient receptor potential melastatin type 6 (TRPM6), claudin 16, and cyclin M2 (CNNM2). These disease were instrumental in gaining knowledge about the reabsorption of Mg 2+ in the kidney. This presentation provides an extensive and comprehensive overview of Mg 2+ reabsorption in the kidney and disturbances which may result in hypomagnesemia. This includes hypomagnesemia that is the consequence of the use of certain types of drugs, such as diuretics, epidermal growth factor receptor inhibitors and proton pump inhibitors.

Conclusion:

Studying hereditary hypomagnesemia aids to increase our understanding of renal Mg 2+ handling.

Factors affecting magnesium status, requirements, and recommended dietary intakes

Research Nutritionist Consultant, Research Nutritionist and former Center Director, Grand Forks Human Nutrition Research Center, Grand Forks, North Dakota, USA. Principal Investigator for 14 outpatient and in-house metabolic unit human studies determining the deficiency signs and nutritional importance of boron, copper, iron, magnesium, and zinc. Magnesium studies focused on determining sub-clinical deficiency signs, status indicators, and nutritional requirements. Results still used to make recommendations for daily dietary intakes. Contact: FrostyNielsen@yahoo.com

Biographical Sketch

Forrest Nielsen

Research Nutritionist Consultant -Grand Forks, USA Determination of the public health concern about magnesium (Mg) in health and disease has been confounded by the lack of practical measures of status, and thus resulting in difficulty in determining nutritional requirements. Some attempts at associating Mg with a chronic disease have used the current United States Dietary Reference Intakes (DRIs) as a status assessment measure. Use of these DRIs is problematic because recent evidence suggests that they should be updated and based on body weight. Based on this evidence, suggestions for the Estimated Average Requirement (EAR) and Recommended Dietary Allowance (RDA) for a 70 kg individual are 175 and 250 mg/day, respectively. However, numerous dietary and physiological factors can affect the need for Mg, and thus affect the use of the current or suggested DRIs to assess Mg status. Calcium intakes above the normal requirements might decrease Mg balance and exacerbate signs of Mg deficiency. Magnesium deficiency apparently occurs often in obesity because of increased need to counteract inflammatory stress induced by adipose tissue dysfunction. Deficiency in anti-oxidant nutrients such as vitamin E and selenium can exacerbate a response to low dietary intake. Dietary modifiers of Mg absorption and excretion affect balance and thus the need for Mg. Factors decreasing Mg balance include low dietary protein and non-fermentable fiber, while factors that can increase balance include fructose and fermentable fiber and fructose-containing oligosaccharides. Establishing DRIs to assess the Mg status of an individual or a population group needs to consider their physiological characteristics and dietary habits and be aware the DRIs may need updating.

Director of the Institute of Cardiovascular and Medical Sciences, University of Glasgow, UK. She has received numerous academic and research awards from the American Society of Hypertension, the Canadian Society of Hypertension, the Quebec Society of Hypertension, the American Physiological Society and the American Heart Association (AHA). Her main focus of research relates to molecular, cellular and vascular mechanisms of hypertension. Prof Touyz is a clinician-scientist and her areas of research include clinical and experimental hypertension, signal transduction, oxidative stress, ion transport, vascular biology, adipose tissue biology and diabetes. She has a particular interest in translational and clinical research. Specific areas of research include 1) NADPH oxidases, oxidative stress and redox signaling; 2) vascular biology of angiotensin II and aldosterone; 3) TRPM6/7 and ion transport in the vasculature and 4) tyrosine kinases, inflammation and vascular remodeling. Contact: Rhian.Touyz@glasgow.ac.uk

Biographical Sketch

Magnesium is a vital and abundant intracellular divalent cation involved in all major cellular and physiological processes, primarily through its nucleotide-binding properties and its regulation of enzymatic activity. Derangements in magnesium homeostasis, which have the potential to contribute to birth defects and multiple clinical pathologies, including arrhythmias, diabetes and cardiovascular disease, are likely under-detected and under-reported. Physiologically Mg 2+ regulates cell growth, apoptosis, migration and contraction/dilation and is especially important in the normal contractile functioning of the heart and vessels. Pathologically, perturbations in [Mg 2+ ]i and alterations in magnesium transporters influence cellular inflammation, fibrosis, cytoskeletal disorganization, immune dysregulation and contraction/dilation. Clinically Mg 2+ deficiency and mutations in magnesium transporters have been implicated in various disorders including neurodegenerative diseases, immune-deficiency, pre-eclampsia, stroke, metabolic and cardiovascular diseases. Factors contributing to hypomagnesemia include drugs (diuretics, EGFR) inhibitors, calcineurin inhibitors, laxatives and proton pump inhibitors), diet, kidney disease and malaborption syndromes. The role for magnesium as a therapeutic agent is being tested in numerous clinical trials. This presentation will present new insights into the molecular biology and transmembrane transport of magnesium and will discuss clinical implications of magnesium in health and disease with a focus on vascular biology and cardiovascular disease.

Dr Rios obtained his PhD in 2009 (Immunology) from the University of Sao Paulo (Brazil) and Karolinska Institute (Sweden). Following a post-doctoral fellowship in Sao Paulo, he moved to Glasgow in 2013 as a Research Fellow at the Institute of Cardiovascular and Medical Sciences, University of Glasgow, UK. He has published more than 40 peer-reviewed papers and presented numerous talks at national and international conferences. His research focuses on the role of TRPM7 on the inflammatory response with a particular interest on how TRPM7 influences immune cell activation and effects on cardiovascular diseases. Contact: Francisco.Rios@glasgow.ac.uk

Biographical Sketch

Chanzyme TRPM7 protects against cardiovascular inflammation and fibrosis

Stella Lucia Volpe

Biographical Sketch

It has been well-established that magnesium is a required micronutrient for over 300 reactions in the body. Many of these metabolic reactions are related to energy production and expenditure. Despite its relationship to energy production and energy expenditure, there are a paucity of data on the effects of magnesium on athletic performance. For this presentation, research on the following will be discussed: 1) Assessment of magnesium intake in various athletes; and, 2) Effects of magnesium supplementation on athletic performance.

Introduction: critical issues on magnesium status and magnesium assessment, from cell to clinic

Biographical Sketch

This speech will introduce a roundtable on the assessment of magnesium status, focusing on current knowledge and future trends. Suboptimal magnesium intake in a large part of the population in western countries supports an increased risk of latent magnesium deficiency. This mild and chronic deficiency is linked to a wide spectrum of health disorders that can be considered nonspecific and can lead to progressive and severe health deterioration, especially cardiometabolic diseases. In turn, several pathophysiological conditions e.g. metabolic syndrome, obesity, type 2 diabetes, stress and dysfunctions related to aging can contribute and aggravate chronic magnesium deficiency. The diagnosis of latent deficiency is difficult because of nonspecific clinical symptoms and magnesemia often within reference intervals. Current clinical laboratory tests are almost limited to total serum magnesium. Less frequently ionized serum magnesium, red blood cell magnesium and urinary excretion of magnesium are measured. However, the assessment of magnesium status to diagnose latent deficiency remains problematic because only subtle changes occur in these parameters and there is a large inter-individual variability. Magnesium is primarily an intracellular cation and is found mainly in bone and soft tissues. Therefore, it is difficult to develop a rapid and robust test representative of intracellular magnesium or body magnesium in humans. The purpose of the presentation and the roundtable is to discuss progress in various areas (chemistry, molecular biology, mass spectrometry), offering great opportunities for the development of new methods for evaluating magnesium status, e.g. use of stable isotopes of magnesium, new dyes for intracellular magnesium or magnesium metabolism related gene expression measurements. In addition, it can be considered that magnesium deficiency diagnosis and deficiency risk patterns can be obtained from combined data composed of questionnaires, laboratory tests and physiological measurements.

Andrzej Mazur

Human Nutrition Unit, INRA and University of Clermont Auvergne, Clermont-Ferrand, France The importance of "being" (and measuring) magnesium Prof. Stefano Iotti, currently works at Department of Pharmacy and Biotechnology of the University of Bologna coordinating the research group of Molecular Imaging, Biosensors and Cell Biology. He has contributed to the development of in vivo NMR spectroscopy in basic research and in diagnostic applications. His scientific activity ranged from organic and physical chemistry to biochemical thermodynamics. He contributed to the development of a novel approach to simplify the treatment of the thermodynamics of complex systems. At present the research activity is devoted to the study of magnesium homeostasis in cell culture combining synchrotron X-ray fluorescence and the use of a novel class of fluorescent chemo-sensors. Contact: stefano.iotti@unibo.it

Biographical Sketch

Purpose: In my speech, I talk about the involvement of magnesium in the fundamental biochemical processes of cell life and how different approaches and techniques for detecting and quantifying magnesium in cells allows to unveil new aspects on its metabolic role.

Materials and methods: Different techniques capable of assessing Mg in living tissues and cells will be presented:

a) studies employing 31P-NMR in vivo to study the Mg homeostasis in vivo in the human brain and skeletal muscle; b) the application of a novel class of fluorescent dyes capable to assess the total intracellular Mg concentration; c) innovative approaches to quantify and mapping Mg in single cells by synchrotron-based x*-ray microscopy techniques.

Results: Several studies will presented showing the possibilities offered by the different approaches presented to untangle at least in part the complex role of Mg in different fundamental metabolic processes of living organisms Conclusion: The involvement of Mg in the main metabolic pathway is well known. However, the complete comprehension of the molecular mechanisms governing the Mg homeostasis is still far away.

Stefano Iotti

Department of Pharmacy and Biotechnology (FABIT), University of Bologna, Bologna, IT National Institute of Biostructures and Biosystems-Rome-Italy

Purpose: To develop fluorescent indicators for organelle-specific visualization and quantitation of cellular Mg 2+ Materials and methods: Fluorescent sensors were synthesized and characterized by a combination of NMR, MS and UV-Vis absorption and fluorescence emission techniques. Metal binding profile in vitro was studied in aqueous PIPES buffer at pH 7. Magnesium detection in various cells lines was demonstrated by widefield microscopy. Organelle targeting was assessed by fluorescence colocalization with organelle stains in microscopy images.

Results: Ratiometric fluorescent sensors functionalized with lipophilic cations for mitochondria targeting, or a chlorohexyl moiety for in cellullo covalent attachment to HaloTag-fused proteins in specific organelles, were synthesized and characterized by various spectroscopic techniques. The sensors display low millimolar dissociation constants for Mg 2+ suitable for detection of intracellular free Mg 2+ . Phosphonium-functionalized sensors displayed preferential accumulation in mitochondria, whereas protein-conjugated sensors could be directed to various organelles such as the nucleus and Golgi. A fluorogenic two-step protein biooconjugaton protocol, incorporating a tetrazine quencher, was developed for the purpose of increasing the signal-to-background ratio in microscopy imaging using the hybrid sensors. Through this protocol, local activation of the fluorescence signal can be achieved within organelles of interest with ~10 fold enhancement upon protein conjugation. A simpler, one-step bioconjugation protocol was also developed and demonstrated. The hybrid sensors combine the fast ratiometric response characteristic of small-molecule fluorescent sensors with the ease of subcellular localization of genetically encoded proteins. Furthermore, the hybrid design enhances significantly the intracellular retention of the sensors, enabling observation of Mg 2+ changes in time course experiments lasting more than 18 h; these could not be performed with current small molecule sensors due to their rapid extrusion from the cell. The new sensors and bioconjugation strategies display general applicability, and Mg 2+ changes in various cellular process could be monitored.

Conclusion:

Small-molecule fluorescent indicators can be functionalized with organelle-targeting moieties to direct their subcellular localization. A general strategy for local activation of the fluorescence via fluorogenic bioorthogonal reactions within organelles enables constraining the signal to compartments of interest. Hybrid sensors also enable long term imaging that is limited with small molecule counterparts. The new sensors and staining methodologies enable imaging of intracellular metal mobilization with subcellular resolution and low background.

Biographical

Clinical detection of cellular magnesium: the Kuwait clinical trial

Professor of Biochemistry and Molecular Medicine, and Medicine (Cardiology), the George Washington University School of Medicine and Health Sciences.

His earlier research on the role of oxidative stress/free radicals in cardiovascular ischemia/reperfusion injury led to the ESR spin trapping/identification of some of the injurious elevated ROS species, and the characterization of cardioprotective drugs with antioxidant potency. Later studies of the cardiomyopathy due to magnesium deficiency (MgD) identified: elevations of superoxide and nitric oxide in rodent models, and the role of substance P-induced neurogenic inflammation in the pathobiology due to MgD. Contact: wweg@gwu.edu

Biographical Sketch

Purpose: To assess cellular and circulating levels of magnesium in hypomagnesemic type 2 diabetic patients before and after supplementation with oral magnesium tablets, and the effects on parameters of oxidative stress and inflammation.

Materials and Methods:

This single arm study of 47 hypomagnesemic diabetic patients was performed over a three month period, and was supported by a grant from the Kuwait Foundation for Advancement of the Sciences. Patients were screened for exclusion criteria before signing consent forms. The study was registered in clinicaltrials.gov/NCT01980459. Participating patients (32% non-obese and 68% obese) were supplemented with 336 mg of Mg (as MagTab SR tablets from Niche Pharmaceutical Co., TX). The clinical staff of DDI were trained to obtain and perform slide fixation of the sublingual mucosal cells for elemental X-ray analysis (EXA Test, Intra-Cellular Diagnostics, Inc., Medford, OR). Serum magnesium levels were obtained monthly along with CRP, TNFα, HbAIc, 8-isoprostane, and the clinical assessment of BP, EKG and other parameters for safety at the DDI clinical / research laboratory site. The low normal serum Mg level at the DDI was 0.74mmol/L (1.8 mg %). The serum Mg of patients initially averaged 0.71 mmol/L and, rose to 0.73 mmol/L (p<0.001) after three months. The matched cellular Mg (normal range 34-42 mEq/L) rose from 33.1 to 35.5 mEq/L (p<0.01); interestingly, the cellular potassium (reference range 80-240 mEq/L) rose from 144 to 185 mEq/L, (p<0.01), both in normal range. The TNFα levels decreased from 9.1 to 6.1 (p<0.001) and 8-Isoprostane levels decreased from 91.7 to 71.7 pg/mL (p<0.05). The CRP levels and HbA1c levels did not decrease significantly over the three month period.

Conclusion:

Treatment of hypomagnesemic type 2 diabetic patients with 336mg/day of Mg lactate tablets significantly increased the cellular and serum Mg levels to normal range along with significant elevations of normal K cellular levels; significant decreases were found for TNFα and 8-isoprostane levels.

Biographical Sketch

Bogdan Milojkovic

Nova Biomedical, Waltham, MA, USA

Importance of ionized magnesium measurements in various clinical settings

Purpose: In normal adults serum magnesium is present in three forms: 20% is protein bound, 65% is in ionised form and the rest is complexed with various anions such as phosphate and citrate. Magnesium testing nowadays is mainly performed by the central laboratory measuring serum magnesium. Central laboratory methods measure the total magnesium (tMg) present in serum and do not distinguish between the three forms, mentioned above. As such the levels of ionized magnesium (iMg), the physiologically active component, in blood or serum are often not known.

There is evidence to show that monitoring and managing ionized dysmagnesemia improves outcomes compared to using total serum magnesium. For example, evidence shows that targeting magnesium correction therapy on the basis of iMg instead of tMg improves outcomes in critically ill patients. iMg can also be useful in unmasking unrecognized hyper-and hypo-magnesemic and false hyper-magnesemic hemodialysis patients. Ionized dysmagnesemia has been reported in various other clinical conditions.

However, until recently iMg testing has not been available as a routine marker and as such is not being monitored routinely in patients. Today iMg is available as a marker on a low maintenance point of care blood gas analysers together with other relevant parameters. This provides an opportunity to elucidate further the role of iMg as a one of the key parameters in managing patients in different clinical settings.

The aim of my presentation is to give an overview and elucidate potential importance of ionized magnesium testing in different clinical conditions.

Bogdan followed academic research pathway after graduating from School of Medicine in Belgrade, Serbia. He's done postdoctoral research at Yale University (USA), ERASMUS Medical Center (Netherlands) and Dundee University. He then transitioned to clinical research working for NIHR Clinical Research Networks managing studies in stroke and dementia. His next assignments took him to pharmaceutical industry where he worked for Allergan and Novo Nordisk. Last 5 years he spent in diagnostics industry working for Roche diagnostics and now leading EU Medical and Scientific Affairs team for Nova Biomedical. Contact: Bmilojkovic@novabio.com Associate Director of Biomedical Research, Center for Biomedical Research, The Queen's Medical Center, Honolulu, HI, USA. Her research focuses on cellular signaling events as they relate to health and disease by elucidating ion channel function and its relationship to cell signaling. Mediated by very fruitful national and international collaborations, this work has led to the original identification and biophysical as well as functional characterization of several novel ion channels, including the channel-kinase TRPM7. TRPM7 has been identified as a central mechanism for magnesium homeostasis, and possibly trace metal regulation, in mammals. Her current work has expanded into medical drug development focusing on ion channel targets with the vision to translate her research into patient care. Contact: afleig@hawaii.edu

Biographical Sketch

Purpose: The last two decades have seen the identification of several protein targets implicated in cellular and systemic magnesium homeostasis [1,2]. Some of these targets have been validated functionally to act as bona fide magnesium channels/transporters. Others await functional confirmation, and still others cannot be regarded as direct magnesium transporters anymore. This presentation will provide a brief history of magnesium channels and transporters and a brief overview on the latest consensus.

Kolisek M, Sponder G, Pilchova I, et al (2018) Magnesium Extravaganza: A Critical Compendium of Current Research into Cellular Mg

Andrea Fleig

Center for Biomedical Research, The Queen's Medical Center and University of Hawaii Cancer Center, Honolulu, USA

Magnesium channels and transporters, an overview

Group leader at the Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, LMU Munich, Germany. The aim of her research is to gain a better understanding of the importance and regulation of cation channels at the cellular level as well as in the context of in vivo immune reactions. This should lead to the identification of novel pharmacological targets against pro-inflammatory diseases, leukemia and allergies. Particular interest lies on the melastatin-like 'transient receptor potential' TRP divalent cation channel TRPM7, and its enzymatic domain, which encodes for a serine/threonine kinase. Contact: susanna.zierler@lrz.uni-muenchen.de

Biographical Sketch

Susanna Zierler

Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, LMU Munich, Munich, Germany

TRPM7-channel-kinase activity in cellular signalling and in vivo immune reactions

Purpose: The dual-function transient-receptor-potential protein, TRPM7, combines a Ca 2+ -and Mg 2+ -permeable channel with a serine/threonine kinase. It has been shown to be essential for immune cell proliferation and development. However, the precise mechanisms how TRPM7 is involved in immune regulation remain elusive.

Materials and methods: Using different genetic mouse models, we decipher an essential role for this unique channel-kinase in cellular signaling and in vivo immune function.

Results: Investigating the role of TRPM7-kinase in balancing immune system homeostasis, we found that its disruption in mice triggers altered susceptibility to allergic reactions. Our findings highlight a regulatory role of Mg 2+ and TRPM7-kinase activity on mast cell degranulation and immunological reactivity [1]. Previously it was shown that conditional knock out of Trpm7 in the T cell lineage disrupts thymopoiesis, and results in altered cytokine expression profiles. Using a homozygous kinase-dead mouse model with a single point mutation at the active site of the kinase, we demonstrated that TRPM7-kinase activity is not essential for thymopoiesis. Importantly, we found that the enzymatic activity of TRPM7 is required for intraepithelial T cell homeostasis. Kinase-dead mice lack gut intraepithelial T cells due to an intrinsic defect in CD103 transcriptional regulation. TRPM7-kinase activity controls TGF-β-induced CD103 expression as well as proinflammatory TH17 cell differentiation, but is dispensable for anti-inflammatory, regulatory T cell (Treg) differentiation. Notably, we identified the C-terminal SXS-region of SMAD2 as novel substrate of the TRPM7-kinase. Moreover, we found that the TRPM7-kinase activity promotes gut colonization by T cells in acute graft-versus-host-disease [2].

Conclusion: Thus, our results unravel a fundamental role of the TRPM7-kinase in immune cell function and suggest a therapeutic potential of kinase inhibitors in averting allergic ractions and acute graft-versus-host-disease. Reinstation of immune homeostasis via TRPM7-kinase blockade might also be beneficial for the treatment of autoimmune diseases.

TRPM7-dependent gene transcription

Director of Walther Straub Institute of Pharmacology and Toxicology, LMU Munich, Germany; Vice Dean of the Faculty of Medicine, LMU Munich, Germany He is a member of the German National Academy of Sciences and has received various awards from national and international scientific societies, i.e. German Society of Endocrinology, Society of Toxicology. He is currently heading a large center grant of the German Research Foundation (DFG), Transregional Collaborative Research Center 152, focusing on the maintenance of body homeostasis by Transient Receptor Potential (TRP) ion channels. In addition, he is speaker of a research consortium, Research Training Group 2338, dealing with the identification of molecular targets in lung toxicology, also funded by the German Research Foundation (DFG). His main focus of research relates to the physiological and pathophysiological role of TRP channels for mineral homeostasis, the role of G protein-coupled receptors in mechanobiology, and the identification of new therapeutic targets in lung toxicology. Contact: thomas.gudermann@lrz.uni-muenchen.de

Biographical Sketch

TRPM7 is a unique member of the transient receptor potential channel TRP superfamily. At its cytosolic C-terminal end TRPM7 contains a serine/threonine protein kinase domain. The relationship between TRPM7 channel and kinase activity is only partially understood. The TRPM7 channel domain modulates kinase activity through changes of the intracellular Mg 2+ concentration. Genetic inactivation of the trpm7 gene at different developmental stages in mice underscored a major impact of TRPM7 on the induction of developmental gene programs. Mechanistically, at least two different general modes of gene regulation by TRPM7 have been worked out: The kinase domain has been reported to be cleaved and to translocate to the nucleus to modify the epigenetic chromatin phosphorylation landscape thereby affecting gene expression profiles. An additional mechanism has recently been uncovered by us in T lymphocytes where a transcription factor, Smad2, is phosphorylated by TRPM7 kinase to control TGF-β induced gene expression. Here, we report a novel general mechanism of gene regulation by TRPM7. TRPM7 blockade results in growth arrest of carcinoma cells in vitro and of xenografts in vivo. Therefore, the TRPM7 channel may represent a promising new oncology target at the plasma membrane. The PRL phosphatases-CNNMs complex, a magnesium-dependent autoregulate system in the maintenance of intracellular magnesium homeostasis and cellular bioenergetics Michel L. Tremblay Purpose: The Phosphatase of Regenerative Liver (PRL) enzymes (PRL-1,-2,-3; gene name PTP4A1, PTP4A2, PTP4A3) are members of the protein tyrosine phosphatase family. These enzymes have been identified as key contributors to tumor progression and metastasis in several human cancers, yet the molecular basis of their pro-oncogenic property is unclear. To better understand their function and mechanism of action we investigated their contribution to magnesium homeostasis and its consequences on cellular metabolism.

Thomas Gudermann

Thomas

Materials and methods:

We employed several approaches from: mass spectrometry studies, biochemical and cell based assays, and knockout mouse models to characterize the function of the mammalian PRLs-CN-NMs complex.

Results: Using mass spectrometry studies, we identified the CNNM magnesium transporter as key binding partners of PRLs in an evolutionarily conserved complex that regulates the intracellular magnesium concentration. Importantly, either the abolishment of complex formation or PRL-2 knockdown resulted in reduced magnesium transport. As cellular magnesium transport is regulated by intrinsic mechanisms controlling various magnesium transporters and magnesium uptake in cells, we also aimed to examine the involvement of PRLs in the adaptive response related to changes in magnesium availability. Using various cell lines cultured under low magnesium conditions, we observed a decrease in intracellular magnesium levels correlating with a marked increase of PRL-1 and -2 (PRL-1/2) expression. Although the expression levels of the magnesium transporter CNNM3 remained unchanged after magnesium depletion, we found that the interaction between endogenous PRL-1/2 and CNNM3 was also markedly increased, indicating a pivotal regulatory role for PRL-1/2 in the complex to compensate for decreased magnesium availability. In addition, we uncovered that this rapid change of PRL expression, modulated by intracellular magnesium levels, employs a mechanism involving its 5' untranslated mRNA region. Mutations or targeting by CRISPR/Cas9 of a conserved upstream open reading frame present in the mRNA leader derepresses PRL protein synthesis and attenuate the translational response to magnesium levels. Mechanistically, magnesium depletion reduces intracellular ATP levels but upregulates PRL protein expression via activation of the AMPK/mTORC2 pathway, which controls cellular energy status. Hence, altered PRL-2 expression leads to metabolic reprogramming of the cells.

Conclusion: These findings uncover a magnesium sensitive mechanism controlling PRL expression, which plays a role in cellular bioenergetics.

Magnesium transporters of SLC41 family and Mrs2

Gerhard Sponder is postdoctoral researcher at the Institute of Veterinary Physiology at Free University Berlin, Germany. From the beginning of his scientific career, he has focused on cellular Mg2+ homeostasis, in particular on the functional and structural characterization of the channel Mrs2 that forms the main Mg2+ influx system in mitochondria. Later, his research focused on the physiological relevance of solute carrier 41A1 which represents the main Mg2¬+-efflux system of mammalian cells and its dysregulation is associated with diseases such as diabetes mellitus, hypertension, and neurodegenerative disorders. Also in dairy cows and horses he investigates Mg¬+ transport, especially under metabolically challenging situations like the onset of lactation and equine metabolic syndrome. Contact: gerhard.sponder@fu-berlin.de

Biographical Sketch

The effective regulation of cellular Mg 2+ homeostasis requires mechanisms that mediate influx and extrusion of the ion across the plasma membrane as well as mechanisms conveying intracellular Mg 2+ storage, distribution between organelles and mobilization.

The solute carrier family (SLC) 41 comprises three members (A1-A3) which exhibit distant homology to the bacterial Mg 2+ -transporter MgtE. SLC41A1 is ubiquitously expressed in mammalian tissues with the highest levels in heart, testis, adrenal and thyroid glands, prostate and ovaries (1). The protein is localized in the plasma membrane where it mediates the extrusion of Mg 2+ . This efflux mechanism is strongly dependent on extracellular Na+ implying that the protein acts as a Na+/Mg 2+ exchanger (2).

Knowledge about the role of SLC41A2 in cellular Mg 2+ homeostasis is still rudimentary. The protein seems to be expressed in most human tissues. However, it is unclear if the protein resides in the cytoplasmic membrane or in intracellular compartments [START_REF] Stepura | Magnesium orotate in severe congestive heart failure (MACH)[END_REF].

SLC41A3 has initially been described as a Mg 2+ channel of the plasma membrane. Recent evidence, however, points to a role of this protein as an antiporter localized in the inner mitochondrial membrane mediating the efflux of Mg 2+ . Similar to SLC41A1, the transport activity of SLC41A3 is dependent on Na+ [START_REF] Kisters | Positive effect of magnesium orotate therapy in hypertensive heart disease[END_REF].

SLC41A3 might therefore act as functional counterpart to the mitochondrial Mg 2+ channel Mrs2 mediating the high-capacity uptake of Mg 2+ into mitochondria. This channel was one of the first identified eukaryotic Mg 2+ channels and has been extensively studied over the years. It is a distant homolog of CorA, the main Mg 2+ uptake system in bacteria. Transport via Mrs2 is driven by the strong, inside-negative mitochondrial membrane potential (5). Knock-down of Mrs2 in HEK293 cells eventually leads to cell death. Furthermore, a mutation in Mrs2 has been demonstrated to be causative for the severe and progressive breakdown of myelin in the central nervous system of rats (6). Purpose: MAGT1 and its homologue TUSC3 are alternative subunits of the ER localized STT3B oligosaccharyltransferase complex. MAGT1/TUSC3 are also thought to be required for magnesium homeostasis, perhaps serving as magnesium transporters. Mutations in human STT3B cause a severe form of congenital disorders of glycosylation (STT3B-CDG). Mutations in MagT1 cause XMEN disease, a less severe immunodeficiency disease linked to defective magnesium homeostasis. We sought to determine whether MagT1 is necessary for STT3B-dependent N-linked glycosylation, and to explain why previously characterized MagT1 mutations do not cause CDG.

Materials and methods:

The role of the MagT1 protein in N-linked glycosylation was addressed by a SI-LAC-based quantitative glycoproteomics procedure using HEK293-derived knockout (KO) cell lines (STT3A-KO, STT3B-KO, MagT1-KO/TUSC3-KO). Expression of MagT1, TUSC3 and STT3B was evaluated in fibroblasts derived from patients with MagT1 mutations that presented with either XMEN disease or CDG. Radiolabeling of selected glycoproteins in fibroblasts and HEK293 derived cell lines was performed to detect defects in N-glycosylation caused by MagT1 deletions or mutations.

Results: The quantitative glycoproteomics results indicated that STT3B and MagT1 are necessary for N-glycosylation of a subset of acceptor sites including (a) extreme C-terminal sites in secretory glycoproteins and (b) sites in lumenal loops of multi-spanning membrane proteins including metabolite and ion transporters. Analysis of fibroblasts from MagT1 patients revealed that certain MagT1 alleles are unstable and are functionally repressed by incorporation of TUSC3 into the STT3B complex. Fibroblasts from MagT1-XMEN and MagT1-CDG patients display defects in N-glycosylation of STT3B dependent substrates.

Conclusion: Either MagT1 or TUSC3 are required for full activity of the STT3B oligosaccharyltransferase. We propose that MagT1 involvement in magnesium homeostasis is by an indirect mechanism involving protein hypoglycosylation. The alternative diseases caused by MagT1 mutations (XMEN vs. CDG) are caused by the extent to which TUSC3 replaces defective Magt1 alleles in the STT3B complex.

Professor and Vice-Chair of Biochemistry and Molecular Pharmacology at the University of Massachusetts Medical School. Reid Gilmore's lab has been investigating the biosynthesis and translocation of secretory proteins or integration of membrane proteins into the endoplasmic reticulum (ER) for more than 30 years. Asparagine-linked glycosylation of proteins by the oligosaccharyltransferase is an essential pathway in metazoan organisms because N-linked glycans are important for protein folding, stability, trafficking and function of proteins synthesized in the ER. Defects in N-linked glycosylation, including mutations in oligosaccharyltransferase subunits, cause a family of human diseases known as congenital disorders of glycosylation (CDG). Contact: reid.gilmore@umassmed.edu

Effect of magnesium and vitamin B6 combination on severe stress in healthy adults

Objectives: Animal and clinical studies suggest complementary effects of Magnesium (Mg) and vitamin B6 (B6) on stress. The aim of the current study, sponsored by Sanofi, was to determine the benefit of Mg-B6 combination compared to Mg alone in stressed healthy adults with suboptimal serum Mg concentrations using a validated measure of perceived stress.

Methods: A Phase IV, 8-week randomized, investigator-blind trial (EudraCT 2015-003749-24) was conducted in adults with a Depression Anxiety Stress Scale-42 stress subscale score (DASS-42SS) >18 and serum Mg 0.5-0.85mmol/L (below mean value for healthy adults), randomized 1:1 to oral Mg-B6 (Magne B6®, Mg 300mg; B6 30mg, QD) or oral Mg alone (Magnespasmyl®, Mg 300mg, QD). The following outcomes were analyzed: change in DASS-42 from baseline (BL) to week 8 (wk8) (primary) and week 4 (wk4); incidence of adverse events (AEs).

Results: In the intention-to-treat analysis (n=264 subjects), both treatments substantially reduced DASS-42SS equally from BL to wk8 (Mg-B6, -12.44 points Mg,p>0.05). An interaction (p=0.0097) between BL stress level and treatment warranted subgroup analysis (per analysis plan); adults with BL severe/extremely severe stress (SESS) (DASS-42SS ≥25; n=162) had 24% greater improvement with Mg-B6 vs Mg at wk8 (3.16 points, 95%CI 0.50, 5.82; p=0.0203); there was no difference between arms in the BL normal/moderate stress subgroup (DASS-42SS <25; n=102; p>0.05). Per-protocol analysis and change from BL to wk4 resulted in similar greater improvement in Mg-B6 versus Mg in the SESS subgroup (p<0.05). Overall, 12.1% of Mg-B6-treated and 17.4% of Mg-treated subjects experienced AEs potentially related to the treatment.

Conclusions: These results suggest that oral Mg administration alleviated stress in healthy adults bearing low magnesemia. Supplementation with Mg-B6 combination was not superior to Mg supplementation alone in the whole population studied. Finally, with regard to the level of stress, this study provides clinical evidence supporting the benefit of Mg combined with vitamin B6 over Mg alone in subjects with severe/extremely severe stress.

Biographical Sketch

Professor Gisèle Pickering (MD,PhD, DPharm) is Professor of Medicine and Clinical Pharmacology at the University Hospital of Clermont-Ferrand, France. She coordinates the Inserm CIC 1405 Clinical Research Centre and is a permanent member of the Inserm 1407 Laboratory of Fundamental and Clinical Pharmacology of Pain. Her main topics of research concern the mechanism of action of analgesics, the impact of pain on cognitive-emotional processes and pain management in older persons. She regularly contributes to peer-reviewed publications on Pharmacology and pain, to international meetings and belongs to national and international Pain, Pharmacology and Geriatrics Societies. She is the French Councillor at the European Pain Society (EFIC). She is the author of over 150 publications and the editor of several books. Her interest in Magnesium in the context of Pain has been translational for the last 15 years, and her group published on the interest of Mg on NMDA receptors from animal models of pain to patients suffering from chronic neuropathic pain. She presently coordinates clinical trials with Magnesium in cancer patients, neuropathic pain, and in fibromyalgia, with a special focus on pain relief and quality of life. Her presentation at the SDRM Society meeting in Bethesda will refer to the benefits of Magnesium alone and combined with Vit B6 on stress. Contact: gisele.pickering@uca.fr 50

Magnesium in stress and anxiety: lessons from preclinical and clinical studies

Louise Dye is Professor of Nutrition and Behaviour in the Nutrition and Behaviour Group, in the Human Appetite Research Unit in the School of Psychology, University of Leeds. Louise is N8 Chair in Theme 3 (Improved Nutrition and Consumer Behaviour) and Academic Lead for the University of Leeds of the HEFCE catalyst funded N8 Agrifood Programme. Louise is a Chartered Health Psychologist and British Psychological Society member. She began her career in Human Psychopharmacology and has over 30 years' experience in the assessment of nutritional and pharmacological intervention on cognitive function and wellbeing. She is Associate Editor of Nutritional Neuroscience and the European Journal of Nutrition. Her research interests include functional foods for wellbeing, stress management, mental health and cognitive performance/decline. She has published a number of influential systematic reviews including on the effects of magnesium in stress and anxiety and studies on the effects of different food components to maintain mental performance under conditions of stress. She is a member of the Scientific Advisory Board of ILSI Europe and has served on 5 of their expert groups.

Contact: L.Dye@leeds.ac.uk

Biographical Sketch

This presentation will examine the effects of magnesium in stress and anxiety, drawing on evidence from animal and human studies. Pigs are a good model for human stress since they show susceptibility and behavioural responses to stress. On a commercial farm, pigs experience stressful events throughout their lifecycle. Stress and aggressive behaviours are not only detrimental to the pigs and their welfare but also for performance and production as increased stress/aggression can increase susceptibility to disease. Our systematic review examined studies in which magnesium was given to pigs to examine the effects on measures of stress and aggressive behaviour. As an example, a recent randomised controlled trial of the effects of magnesium with and without phytase on stress related behaviours in pigs experiencing an environmental stressor namely the mixing of pens after weaning will be described and the effects on indicators of stress such as ear, tail and body scores will be presented. Our systematic review of magnesium in humans examined the available evidence for the efficacy of Mg supplementation, alone or in combination, to alleviate subjective measures of anxiety and stress. The strength of the evidence for effects of magnesium on stress related symptoms from human and pig studies is suggestive of a beneficial effect of magnesium on stress related outcomes. However, the quality and consistency of the human studies in particular, precludes firm conclusions. For illustration, the level of stress reported at recruitment in a recent human clinical trial and the comorbidities in that sample which has important implications for future studies will be discussed.

Louise Dye

Human Appetite Research Unit-School of Psychology -University of Leeds, UK

Purpose: Mg 2+ is recognized as a multi-target analogue regulator that performs many roles, such as circadian timekeeping, due to the following properties; (i) it influences wide-ranging biological processes, (ii) its concentration is tightly controlled within a narrow sub-millimolar range, and (iii) its intracellular dynamics are slow and long-lasting; its regulatory manner is not all-or-none in contrast to the switch-like signal transduction by the well-established second messenger Ca 2+ . Recent studies, however, have reported another role for Mg 2+ as a second messenger in immune cells. These multifaceted characteristics of Mg 2+ raise the question of how Mg 2+ processes information and how common its role is as a signaling molecule. We, therefore, investigated the role of Mg 2+ as a second messenger in early developmental stages of neurons with several fluorescent imaging techniques.

Materials and methods:

We focused on the effects of γ-aminobutyric acid (GABA) and its developmental transition. We show that in neurons, GABAA signaling, whose action is excitatory, triggers Mg 2+ release from mitochondria specifically at early developmental stages with several fluorescent Mg indicators. We also demonstrate that released Mg 2+ stimulates the CREB and mTOR signaling pathways with FRET-based sensors. Finally, the Mg 2+ function for neural network maturation was investigated as the fnctional connectivity by Ca 2+ and FM dye imagings.

Results: We found that cytosolic Mg 2+ fluctuations within physiological ranges is enough to crucially regulate ERK, CREB, and mTOR activities; quantitative analysis of the Mg 2+ concentration-response curves demonstrates that cytosolic Mg 2+ regulates the signaling activities of ERK negatively, CREB positively, and mTOR sigmoidally.Together, intracellular Mg 2+ physiologically integrates and coordinates cellular information and Mg 2+ is a novel signal transducer for organizing neural networks.

Conclusion:

We succeed to demonstarate the Mg 2+ as a second messenger in neurons. Mg 2+ has a important role for facilitating structural and functional maturation of neural networks.

Professor, Keio University; Visiting Adjunct Professor, Kaohsiung Medical University His researches are related to intracellular information processing by using fluorescent and other imaging techniques. He has succeeded to simultaneously visualize the cAMP/cGMP behavior in growth cones (Kobayashi et al. Sci. Rep. 2015), ATP and mitochondrial activity in neuronal axons (Suzuki et al. Sci. Rep. 2018), and Ca 2+ and cGMP mobilization in sensory neurons of C.elegans (Shidara et al. J. Neruosci. 2017). Furthermore, for last 20 years, he has been also investigated Mg 2+ mobilization and signal transduction in neurons by developing fluorescent imaging techniques. He demonstrated mitochondrial as intracellular Mg 2+ source, Mg 2+ mobilization by neuronal excitation (Yamanaka et al. Neurosci., 2015), and also nitric mono-oxide (NO) stimulation (Yamanaka et al. FEBS Lett., 2013). Recently he found GABA application induced Mg 2+ mobilization in early stages of developmental neurons and it regulates several kinase activities (Yamanaka et al. Curr. Biol. 2018). Contact: oka@bio.keio.ac.jp

Biographical Sketch

Kotaro Oka

Biographical Sketch

Purpose: Sarcopenia and frailty are becoming increasingly recognised conditions in our ageing society, leading to poor quality of life, falls and fractures. Sarcopenia is the presence of low skeletal muscle mass and function. To date, the majority of nutritional interventions and research have focused on protein as the solution to these conditions. However, dietary magnesium is integral to skeletal muscle physiology and has the anti-inflammatory potential to impact on progression of skeletal muscle loss and function during aging.

Materials and methods:

Epidemiological studies across population cohorts in the UK (TwinsUK, The EPIC-Norfolk Study and the UK Biobank) relating magnesium intake or circulating concentrations in blood to osteoporosis, risk of fracture, low skeletal muscle mass and function have been recently published (Hayhoe et al., 2015, Hayhoe et al., 2018, Welch et al., 2016, Welch et al., 2017).

Results:

We found that dietary magnesium is related to skeletal muscle mass (as fat free mass) in men and women of different life stages. Moreover, our findings were stronger than those with protein intake. Dietary magnesium was also very strongly related to leg explosive power in women, with interquintile differences of 25%. In women dietary magnesium also attenuated the associations between C-Reactive Protein and skeletal muscle mass and function. Magnesium was also related to bone density.

Conclusion:

Dietary magnesium is likely important for musculoskeletal health, particularly in middle and older age.

References: HAYHOE, R. P., et Al & WELCH, A. A. 2015. Am J Clin Nutr, 102, 376-84. HAYHOE, R. P. G., et Al & WELCH, A. A. 2018. Clin Nutr. 2018WELCH, A. A., et Al MACGREGOR, A. 2016. J Bone Miner Res, 31, 317-25. WELCH, A. A., SKINNER, J. & HICKSON, M. 2017. Nutrients, 9.

Ailsa A Welch Welch A.A. & Hayhoe R.P.G1 1 Department of Epidemiology & Public Health, Norwich Medical School, University of East Anglia, Norwich, UK

Ailsa Welch is a professor of Nutritional Epidemiology at the University of East Anglia Medical School. She researches the protective factors in diet for aging particularly for cardiovascular and musculoskeletal health (sarcopenia, skeletal muscle mass and function), osteoporosis and fracture risk. She also researches into cancer, in developing dietary assessment methods, quantifying measurement error, and evaluating public health improvement interventions. Ailsa aims to understand the effects of micronutrients (vitamins & minerals), diet quality (dietary patterns, fatty acids & acid-base load) on aging. Understanding how diet improves health during aging is important as the age profile of populations is increasing with consequences for the burden on health and social care. Micronutrient malnutrition also co-exists alongside obesity and chronic disease. Ailsa has 193 peer-reviewed publications, an H Index of 66 (Scopus), and is a top 1% world researcher (Thompson Reuters, 2014). Ailsa chairs the Nutrition & Lifestyle Forum of the UK National Osteoporosis Society and is a member of their Scientific Advisory Committee. She also chairs an initiative 'Optimising Nutrition and Hydration in Care Homes' and is the Public Health Nutrition scientific theme lead for the UK Nutrition Society. Ailsa is a State Registered Dietitian. Ailsa previously led development of dietary assessment methods for the EPIC-Study at the University of Cambridge, compiled UK food composition databases and researched in Somalia and Nigeria. Contact: A.Welch@uea.ac.uk

The janus of magnesium in the bone MD, Professor of General Pathology at the University of Milan. She was trained in the USA on the pathophysiology of the endothelium, with a focus on aging and senescence. In the last 15 years she investigated the response of vascular cells to magnesium and to the silencing of its transporters. Lately, attention has been devoted also to the role of magnesium in bone homeostasis. Contact: jeanette.maier@unimi.it

Biographical Sketch

A tight control of magnesium homeostasis is important for bone health. Indeed, experimental and epidemiological studies have demonstrated that both low and high magnesium exert harmful effects on the bones. Magnesium deficiency leads to osteopenia indirectly by altering the secretion and the activity of parathyroid hormone as well as the metabolism of vitamin D, and also by promoting low grade inflammation. Moreover, low magnesium directly impacts on crystal formation and shapes the behaviour of bone cells. While it reversibly accelerates mesenchymal stem cell differentiation into osteoblasts, low magnesium inhibits osteoblast function and stimulates osteoclast activity.

Evidence has been provided about harmful effects on osseous metabolism and parathyroid gland function by elevated magnesium. Accordingly, high bone Mg inhibits the formation of hydroxyapatite crystals by competing with calcium and by binding to pyrophosphate forming an insoluble salt. In vitro high Mg retards the osteogenic differentiation of bone mesenchymal stem cells, inhibits osteoblastic mineralizing activity and potentiates osteoclastic differentiation.

Overall, an optimal range of Mg concentrations seems to be required to ensure bone homeostasis. Purpose: Magnesium status is usually assessed by serum levels, but these represent only a fraction of whole-body magnesium, and it is unclear whether they reflect magnesium's physiologic activity. Given that magnesium is a critical cofactor in muscle crossbridge cycling, we used phosphorus magnetic resonance spectroscopy ( 31 P-MRS) to examine skeletal muscle magnesium status, studying its relationship with age and muscle function in a group of healthy men and women dispersed over a wide age-range.

Jeanette AM Maier

Materials and methods:

We obtained 31 P-MRS spectra in 459 participants (215 male, median [range] age=73 [24-98]yrs) of the Baltimore Longitudinal Study on Aging, estimating muscle [Mg 2+ ] in the left thigh using a quadratic equation incorporating the observed chemical shift of β-ATP and the intracellular pH. Additionally, we measured: serum [Mg 2+ ] using a conventional clinical colorimetric assay; and maximum knee-extension torque in the left leg, which was assessed using an isokinetic dynamometer, with isometric contractions being performed at 70° flexion.

Results: Muscle [Mg 2+

] was inversely associated with serum [Mg 2+ ], as shown in Figure 1, and with age, with β=-0.31, p<0.001, R 2 =0.09. The association with age remained significant after segregating by sex, as illustrated in Figure 2, and there was a statistically-significant difference in muscle [Mg 2+ ] between male and female participants (p<0.001). Serum [Mg 2+ ] was not significantly associated with age, and there were no sex differences. Finally, muscle [Mg 2+ ] was associated with knee-extension torque in male and female subgroups (β=0.18, p=0.01, R 2 =0.06; and β=0.35, R 2 =0.12, p<0.001, respectively, adjusting for BMI), while serum [Mg 2+ ] showed no association.

Conclusion:

We found that magnesium in muscle was more-strongly associated with age and muscle function than was serum magnesium. Characterizing muscle changes with age is important for understanding sarcopenia and frailty, and our 31 P-MRS measures of muscle magnesium demonstrate such differences, permitting future testing of dietary, exercise, and pharmaceutical interventions in aging. Materials and methods: We systematically searched PubMed, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) up to December 2018 to identify eligible randomized controlled trials (RCTs) that repoted the mean (standard deviation) changes from baseline to end of follow-up in serum magnesium. Random-effects pairwise and network meta-analyses were performed to calculate the weighted mean difference (WMD) and 95% confidence interval (CI).

Results: Of the 4,751 citations retrieved from electronic databases, 24 RCTs involving 17,396 patients with five SGLT2 inhibitors (canagliflozin, dapagliflozin, empagliflozin, ertugliflozin, and ipragliflozin) were included in this meta-analysis. All SGLT2 inhibitors were significantly associated with increase in serum magnesium as compared with placebo (WMD = 0.08 mmol/L; 95% CI = 0.06 -0.09). Subgroup analyses by types of SGLT2 inhibitors showed that each SGLT2 inhibitor compared to placebo could significantly increase serum magnesium (range: 0.05-0.20 mmol/L). Significant increases in serum magnesium were observed in the network meta-analysis among the patients taking canagliflozin (WMD = 0.08 mmol/L), dapagliflozin (WMD = 0.15 mmol/L), and empagliflozin (WMD = 0.06 mmol/L) compared to those taking placebo. No statistically detectable differences of srum magnesium levels were evident between any two of SGLT2 inhibitors but between dapagliflozin and empagliflozin (dapagliflozin versus empagliflozin: WMD = 0.09 mmol/L). However, significant heterogeneity was observed in these analyses.

Conclusion:

This study confirmed that SGLT2 inhibitors could significantly increase serum magnesium, indicating a potentially similar class-effect. However, more data for long-term efficacy and safety of raising serum magnesium in T2D patients with different clinical phenotypes are needed for further investigation.

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Magnesium supplementation improves diabetic mitochondrial and cardiac diastolic function

Man Liu 1 , Euy-Myoung Jeong 2,3 , Hong Liu 1 , An Xie 1 , Eui Young So 2,3 , Guangbin Shi 2 , Go Eun Jeong 4 , Anyu Zhou 2,3 , Samuel C. Dudley Jr 11 Division of Cardiology, Department of Medicine, the Lillehei Heart Institute, University of Minnesota at Twin Cities, Minneapolis, MN 2 Cardiovascular Research Center, Lifespan Rhode Island Hospital, Providence, RI 3 The Warren Alpert Medical School, Brown University, Providence, RI 4 Brown University, Providence, RI Purpose: In heart failure and type II diabetes mellitus (DM), the majority of patients have hypomagnesemia, and magnesium (Mg) supplementation has improved cardiac function and insulin resistance. Recently, we have shown that DM can cause cardiac diastolic dysfunction (DD). Therefore, we hypothesized that Mg supplementation would improve diastolic function in DM.

Materials and methods:

High fat diet-induced diabetic mouse hearts showed increased cardiac DD and hypertrophy.

Results: Mice with DM showed a significantly increased E/e' ratio in the echocardiogram, left ventricular end diastolic volume (LVEDV), incidence of DD, left ventricular posterior wall thickness in diastole (PWTd), and ratio of heart weight to tibia length (HW/TL) when compared to controls. DM mice also had hypomagnesemia. Ventricular cardiomyocytes isolated from DM mice exhibited decreased mitochondrial ATP production, a 1.7±0.2-fold increase of mitochondrial ROS, depolarization of the mitochondrial membrane potential, and mitochondrial Ca 2+ overload. Dietary Mg administration (50 mg/mL in the drinking water) for 6 weeks increased plasma Mg concentration and improved cardiac function. At cellular level, Mg improved mitochondrial function with increased ATP, decreased mitochondrial ROS and Ca 2+ overload, and repolarized mitochondrial membrane potential.

Conclusion:

In conclusion, Mg supplementation improved mitochondrial function, reduced oxidative stress, and prevented diastolic dysfunction in DM.

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Effect of magnesium bicarbonate-rich water on high normal and hypertension grade 1 blood pressure: a double-blind, placebo-controlled, two-center trial Mašenjka Katić 1 , Sandy Lovković 21 NutriProject Consultancy, Zagreb, Croatia, HR 2 Jamnica d.d., Zagreb, Croatia, HR Purpose: To evaluate the potential of magnesium bicarbonate-rich natural mineral water MgMivela on cardiovascular parameters, in particular to blood pressure, in subjects with high normal or hypertension grade 1 blood pressure levels.

Materials and methods:

This randomized, double-blind, placebo-controlled, two-center pilot study enrolled 50 subjects, 18-65 years old, with high normal or hypertension grade 1 blood pressure (130-159/85-99 mmHg). After a two week run-in phase, 33 subjects were assigned to 1l a day (500 ml in the morning and 500 ml in the late afternoon/early evening) of MgMivela (339 mg/l magnesium, 2074 mg/l bicarbonate) and 17 subjects to placebo water (15 mg/l magnesium, 543 mg/l bicarbonate), for the following 8 weeks.There were four visits at the study centers (Charité University Medicine Berlin and Analyze & Realize GmbH, Germany) during the trial (screening, baseline, control and the final visit). Blood pressure, heart rate measurements, physical examination, blood and urine laboratory parameters, body weight, dietary diary and physical activity questionnaire, assessment of adverse effects and global evaluation of benefit and tolerability of the water consumed were assessed. Statistical analysis was performed by applying General Estimating Equations, Wald Square Chi-square testing, exact Fisher test, Mann-Whitney U test and Wilcoxon test.

Results: There was a significant time-dependant difference in the reduction of blood pressure, showing that consumption of MgMivela over eight weeks yielded in a greater reduction of blood pressure compared to the placebo, with mean difference in systolic blood pressure of -6,1 mmHg vs -1.2 mmHg (p<0.001) and diastolic blood pressure of -4.9 mmHg vs -2.8 mmHg (p<0.001) respectively.

Conclusion:

The consumption of 1l MgMivela water daily over the period of eight weeks was shown to be excellently tolerated and associated with beneficial effects on blood pressure in subjects with high normal or hypertension grade 1 blood pressure. Clinical trial registration DRKS-ID: DRKS00009383 Results: Global Mg supply needs to be corrected for Mg processing losses (estimated -8 to -60%), and human Mg requirements need to be corrected for rising body weights (+6 -11% in 20 years) plus physiological requirements to reduce potential depletion of Mg stores (7 mg Mg/kg vs 4 mg Mg/kg) and estimated impact of high stress levels (10 mg Mg/kg).

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Conclusion:

Global Mg Supply production outpaced the human Mg need due to the rise in human global population, 1991-2011. Even though the global human population rose +25% 1991-2011 (UN data), the per capita human Mg Global Supply rose +9%. Mg supply with processing losses < 38% may meet global human Mg requirement while minimizing or preventing depletion of Mg stores in healthy non-stressed people, but lifelong consumption of diets with larger Mg processing losses, common in several developed countries, can be expected to show higher levels of Mg related chronic diseases mainly seen in the elderly.

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XV International Magnesium Symposium -NIH -Bethesda, USA -March 20 th -22 nd , 2019

Magnesium and its transporters: impact on osteogenic differentiation of human bone mesenchymal stem cells Sara Castiglioni, Valentina Romeo, Jeanette Maier Department of Biomedical and Clinical Sciences Luigi Sacco, University of Milano, Milano, IT Purpose: To assess the effect of low and high magnesium (Mg) as well as Mg transporters on osteogenic differentiation of human bone mesenchymal stem cells (hMSCs).

Materials and methods: hMSCs isolated from adult human bone marrow are cultured in physiological (1.0 mM), low (0.1 mM) or high [START_REF] Stepura | Magnesium orotate in severe congestive heart failure (MACH)[END_REF]6, 10 mM) Mg concentrations. TRPM7 and MagT1 are transiently silenced using specific siRNAs. Osteogenic differentiation is induced by exposing the cells to an osteogenic cocktail containing 2 x 10-8 M 1α,25-Dihydroxyvitamin D3, 10 mM β-Glycerolphosphate and 0.05 mM Ascorbic Acid. Extracellular calcium (Ca) deposition is evaluated staining the cells with 2% Alizarin Red S.

Results: Magnesium deficiency reversibly accelerates the expression of osteogenic markers as well as extracellular calcium deposition in hMSCs. This event is associated with an increased production of reactive oxygen species (ROS). Accordingly, the antioxidant NAC prevents the enhancement of hMSCs differentiation by low extracellular Mg. Since ROS are recognized as fundamental in promoting cell differentiation partly through the enhancement of autophagy, it is noteworthy that low Mg activates this process. Intriguingly, similar results are obtained when the kinase and cation channel TRPM7 or the magnesium transporter MagT1 are silenced. On the contrary, high Mg inhibits hMSCs osteogenic differentiation probably through inhibition of autophagy. We detected a marked reduction of calcium deposition by hMSCs in medium containing 3 mM Mg, while the cells cultured in 6 and 10 mM Mg presented a slight but significant increase of the calcified matrix.

Conclusion:

We argue that both low and high Mg concentrations as well as Mg transporters modulate osteoblastogenesis partly through the modulation of autophagy.

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Cadmium exposure enhances TRPM7 expression and intracellular magnesium leading to EMT in mammary epithelial cells

Alison Vanlaeys 1 , Gregory Fouquet 1 , Sylvie Pasco-Brassart², Thibaut Lefevre¹, Pierre Rybarczyk 1,3 , Frédéric Hague 1 , Philippe Kischel 1 , Isabelle Duthille-Dhennin 1 , Bertrand Brassart 2 , Halima Ouadid-Ahidouch 1 and Mathieu Gautier 1 ¹ EA4667, University of Picardie Jules Verne, Amiens, Fr ² UMR CNRS/URCA 7369, University of Reims Champagne-Ardennes, Reims, Fr ³ Pathological Anatomy and Cytology Department, Amiens's Hospital, Amiens, Fr Purpose: Cadmium is a pollutant that can be absorbed by epithelial cells through divalent cation transporters leading to neoplastic transformation. Among these transporters, the transient receptor potential melastatin-related 7 (TRPM7) is known to allow metal constitutive entries and is involved in cancer cell fates. The aim of this study was to show how TRPM7 is involved in neoplastic transformation induced by cadmium exposure in mammary epithelial cells.

Materials and methods: MCF10A non-cancer epithelial mammary cells were exposed to non-toxic concentration of cadmium for 40 weeks. TRPM7 expression was assessed by western-blot and its activity was studied by both patch-clamp and Manganese quench techniques. The effects of cadmium and TRPM7 silencing on intracellular calcium and magnesium were evaluated by using fluorescent probes as Fura-2 and MagFura-2. Finally, the migratory and invasive properties of cadmium-exposed cells were studied by using non-modified or modified Boyden chambers.

Results: Cadmium exposure induces TRPM7 overexpression followed by an increase of membrane currents and constitutive cation entry. Cells exposed to cadmium have a slight increase of intracellular calcium but the increase is much higher for magnesium levels. TRPM7 silencing restores calcium level but strongly decreases intracellular magnesium under control basal level. Moreover, cadmium exposure enhances both cell migration and invasion and TRPM7 silencing strongly decreases these cell fates. Furthermore, we observe that MCF10A exposed to cadmium became rounded and have less cell-to-cell junctions. Cadmium exposure decreases epithelial markers and increases the mesenchymal ones. Importantly, TRPM7 silencing is able to reverse these phenotypic modifications.

Conclusion:

Our data show that cadmium exposure enhances TRPM7 expression and activity in mammary epithelial cells. TRPM7 overexpression induces intracellular magnesium increase and stimulates MCF10A cell migration and invasion. These neoplastic properties could be linked to a TRPM7-dependant epithelial-to-mesenchymal transition reprogramming in cell exposed to cadmium. These findings provide new insights in the regulation of cancer cell fates by TRPM7 and magnesium.

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The anticancer EGFR-TKI, erlotinib, causes cutaneous, cardiac and hypomagnesemic side effects that were inhibited by aprepitant, a substance P receptor-blocker W. B. Weglicki, J H Kramer, J J Chmielinska, CF Spurney and I T Mak Department of Biochemistry and Molecular Medicine, The George Washington University School of Medicine and Health Sciences, and the Department of Pediatrics, The Childrens National Medical Center, Washington, DC, USA Purpose: To determine the effect of SP-receptor blockade on the side effects of the EGFR-TKI, erlotinib (Tarceva), which has been used successfully to combat small cell lung and other various cancers, which may impact the patient's quality of life and even cause treatment interruption.

Materials and Results:

In early studies of erlotinib-mediated side effects in a rodent model, we observed neurogenic inflammation associated with elevated circulating substance P (SP, 25% increase), ROS/RNS stress (8-isoprostane increased 210%, neutrophil superoxide increased 3-fold), progressive hypomagnesemia (-9% to -26%), skin lesions/ hair loss, increased cardiac nitrotyrosine staining, and mildly impaired cardiac contractile function. During 9 weeks of erlotinib treatment (10 mg/kg/day), co-treatment with the SP receptor blocker, aprepitant (Emend: 2 mg/kg/day): significantly (p<0.05) restored by ~50% the 26% decrease in circulating magnesium levels, inhibited (p<0.01) the increased level of SP, and restored cardiac LV ejection fraction and fractional shortening to near normal levels (p<0.02 ). Most surprisingly, the skin lesions/hair loss due to erlotinib treatment were largely prevented by SP receptor blockade. In a more recent study, when the rodents were placed on a 40% Mg-deficient diet for 12 weeks, a 21% lowering (p<0.01) of circulating Mg occurred, and co-treatment with erlotinib lowered the Mg level further to 30% below control (p<0.01). This combination of erlotinib treatment with dietary hypomagnesemia enhanced the severity of skin lesions and the impairment of cardiac contractile function.

Conclusion:

These results indicate that co-existing hypomagnesemia may worsen the above side effects during erlotinib therapy and neurogenic inflammation. Our intervention studies with the FDA-approved anti-nausea drug, aprepitant, suggest a novel potential therapy to prevent these known clinical side effects experienced by EGFR-TKI-treated cancer patients. (supported by NIH R21 HL108311 and GWU McCormick Center Genomic and Proteomic Supplemental Fund)

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Magnesium pidolate vs magnesium sulphate: which salt performs better to protect the brain? Romeo V. 1 , Locatelli L. 1 , Scrimieri R. 1 , Castiglioni S. 1 , Maier J.A.M. 1 , Cazzaniga A. 1 1 "L. Sacco" Department of Biomedical and Clinical Sciences, University of Milan, Via G.B. Grassi 74, 20157 Milan, IT Purpose: The blood-brain barrier (BBB) consists of an interdependent network of cells designed to isolate the central nervous system from the systemic circulation. The loss of BBB integrity or changes of its permeability are associated with several neuropathological disorders and approaches to augment or stabilise the BBB are lacking. The aim of this study was to evaluate the effect of magnesium sulfate (MgSO4) and Mg pidolate in in vitro BBB-models.

Materials and methods: Co-cultures using the Transwell system were performed. Astrocytes were cultured in the lower part of the transwell and endothelial cells on the upper side. The change of permeability was studied by measuring bovine serum albumin-fluorescein isothiocyanate conjugate passage through the BBB and by transendothelial electrical resistance across the apical and basal compartments. Mg levels in the lower chamber was evaluated using the DCHQ5 fluorescent probe. The modulation of ZO-1 was investigated by immunofluorescence and the levels of some Mg transporters by western blot.

Results: High concentrations of Mg salts reduce BBB permeability and allow the accumulation of Mg in the lower chamber. No modulation of the levels of TRPM7 and MagT1 was detected. ZO-1 seems to be differently distributed upon exposure to high concentration of Mg salts. We also demonstrate that 5 mM of Mg salts protect against the increase in permeability induced by LPS. Mg pidolate seems to perform better that MgSO4.

Conclusion:

Our results can be summarized as follows: i) Mg is involved in the modulation of BBB's permeability, thereby indicating that high concentration of Mg salts could be used to prevent the accumulation of toxic molecules in the brain; ii) Mg pidolate is more efficient than MgSO4 in preventing BBB permeability alteration by inflammatory stress; iii) Mg pidolate tends to cross the BBB more than MgSO4.

Sanofi has sponsored this study. Purpose of Study: Chronic latent magnesium (Mg) deficiency (CLMD) along with decreased dietary intake of Mg is common and may incur increased risk for several chronic diseases. To evaluate the risk profile of women participating in the USDA Mg depletion studies by their serum calcium (Ca)/serum Mg ratios (mg/dL) and EKG parameters.

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OC19 OC22

Methods Used: Three USDA depletion-repletion studies in 39 healthy postmenopausal women were analyzed for changes in the Ca/Mg ratio with or without QT interval changes on the EKG during the study period (mean of 5 complexes/reading corrected for heart rate; QTc), consuming a depletion diet between 104 to 146 mg Mg/day lasting from 72 to 93 days.

Results:

Serum measures throughout the study period were paired with EKG QTc measures. Mean serum Mg was 1.99 + 0.18 mg/dL, mean serum Ca was 9.33 +0.37 mg/dL. Mean QTc was 0.419 ± 0.02 msec. Repletion mean differences were statistically significant between groups 127 vs 132 (p=0.001), 127 vs 135 (p=0.001) and 132 vs 135 (p=.005) due to an elevation of serum Ca. A low serum Mg (<2.1) and increased QTc were present in 7/11 women in group 127.

Conclusion:

A Mg repletion diet lead to elevations in the Ca/Mg ratio primarily due to increases in serum Ca, not serum Mg, which was also reflected by EKG changes. The EKG, in combination with serum Mg, may help detect CLMD. Purpose: After parturition, dairy cows show a dramatic increase in the demand for energy. Especially, the requirement of glucose increases because of the onset of lactation. The feed uptake lags behind energy demand. This negative energy balance results in an increased mobilization of body fat and the synthesis of ketone bodies. Both are linked to insulin deficiency and/or insulin resistance, analogical to diabetes mellitus in humans. Magnesium plays a crucial role in insulin signaling and many enzymatic pathways. Therefore, the aim of the study was to investigate the influence of different magnesium and insulin concentrations on glucose uptake as a measure of insulin sensitivity in bovine adipocytes.

Repletion

Materials and methods: Subcutaneous adipose tissue was collected from young calves and preadipocytes were cultivated as an explant culture. After 2 days of induction, adipocytes were incubated with various magnesium concentrations (0.1mM, 0.3mM, 1mM and 3mM) and various insulin concentrations (25pM, 250pM and 25nM) for 14 and 21 days. Glucose uptake was investigated using the fluorescent glucose analogue 6-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino]-2-deoxy-d-glucose (6-NBDG) and normalized to DAPI fluorescence of cell nuclei. Statistics were conducted by two-way ANOVA.

Results: After an incubation over 14 days, the normalized glucose uptake (glucose/nuclei ratio) showed a trend to rise with higher insulin concentrations (P = 0.063) with no effect of the magnesium concentration. After 21 days of culture, the glucose/nuclei ratio at 25pM and 250pM insulin was lower than at 25nM insulin concentrations (P < 0.05). Furthermore, a low magnesium concentration of 0.1mM caused a decrease in glucose uptake compared to all other tested magnesium concentrations (P< 0.05).

Conclusion:

Increasing concentrations of insulin stimulate glucose uptake of cultivated bovine adipocytes. Magnesium has an additional positive impact on glucose uptake of adipocytes, which becomes especially evident at later stages of adipocyte differentiation.

This work was supported by the Elsa-Neumann-Stipendium

TRPM7 is a potential pharmacological target in progressive kidney fibrosis

Sayuri Suzuki¹, Reinhold Penner 1,2 , Andrea Fleig Purpose: Unilateral Ureteral Obstruction (UUO) is a representative model of chronic nephritis with progressive tubulointerstitial injury and renal fibrosis occurring by inflammation, cell proliferation and apoptosis. Blocking tubular epithelial cell proliferation is crucial to preventing the progression of kidney damage. TRPM7 belongs to the Transient Receptor Potential Melastatin family of ion channels, is a Mg 2+ -conducting ion channel fused with a functional kinase. TRPM7 plays a key role in a variety of diseases, including malaria invasion, neuronal death in ischemia, cancer and cardiac fibrillation. TRPM7 is aberrantly over-expressed in lung, liver and heart fibrosis. It is also overexpressed after renal ischemia-reperfusion, an event that induces kidney injury and fibrosis. However, the role of TRPM7 is unclear in kidney fibrosis. In this study, we establish TRPM7 is an anti-fibrotic target in vivo and provide a novel pharmacological tool for drug development against kidney fibrosis.

Materials and methods:

We created UUO mouse model on male C57BL/6 male, 5 weeks old, compared the expression level of TRPM7 in UUO kidneys and control kidneys at Day7 using qRT-PCR, western blotting assay and immunohistochemistry. Next, we injected NS8593 as TRPM7 inhibitor to UUO mice whether NS8593 suppresses TRPM7 in UUO kidney and attenuates renal fibrosis.

Results:

The expression levels of TRPM7 mRNA and protein in UUO kidneys were higher than control kidneys, TRPM7 particularly increased on tubular epithelial cells. The TRPM7 positive cell number increased twice on both of renal tubular epithelial cells and tubulointerstitial cells in UUO kidneys compared to control kidneys. NS8593 completely blocked TRPM7 mRNA in UUO kidneys compared to control group. And it decreased the produce of extracellular matrix, attenuated renal fibrosis.

Conclusion:

TRPM7 up-regulated in progressing inflammatory renal damage, NS8593 protected from the progressive kidney fibrosis. NS8593 could be capable of inhibiting kidney cell proliferation and fibrosis in renal disease.

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P07

Magnesium (Mg) deficiency enhances oxidative stress and migratory potential of colon cancer cells

Gopal Kumar 1,2 , Swati Madankumar 2 , Xiangying Xue 2 , Prodyot Chatterjee 2 and Christine N Metz 1,2 ¹ Elmezzi Graduate School of Molecular Medicine, Manhasset, NY 2 The Center for Biomedical Sciences, Feinstein Institiute for Medical Research, Manhasset, NY Purpose: The purpose of this study was to assess the role of Mg deficiency (which increases Ca:Mg ratio), oxidative stress and TRPM7 signaling in promoting colon cancer cell motility in an in vitro model system.

Materials and methods: CT26 colon cancer cells were grown in media containing either 100%Mg, 50%Mg or 10%Mg (with constant concentrations of Ca) or in media containing either 100%Mg/100%Ca, 50%Mg/50%Ca or 10%Mg/10%Ca for 48hrs. qPCR and western blotting of cell lysates were performed to assess various markers associated with FAK, NFκB, E-cadherin and p53 signaling, as well as oxidative stress. Cells were grown under similar conditions and the DCFDA assay was performed for oxidative stress and Fluo-4-AM was used to measure intracellular Ca. Cell motility was measured by scratch assay.

Results:

We observed that MgD cells showed higher intracellular Ca with increased expression of TRPM7 (that regulates intracellular Mg & Ca homeostasis). MgD also increased oxidative stress as measured by DCFDA assay and Gpx1 mRNA expression. Furthermore, MgD enhanced the motility of the colon cancer cells. This was consistent with the observed degradation of full length E-cadherin as well as that of N-terminal FAK, a cytoplasmic tyrosine kinase, which negatively regulates FAK activity by increasing the cycling of the focal adhesions. MgD also degraded IκBα and the TAD containing C-terminal of p65. We also observed degradation of the p53 protein, as well as its transcriptional repression in MgD cells; loss of p53, promoting genomic instability, would be expected to increase metastatic potential in the long run. When the Ca:Mg ratio was kept as 1 these effects were not observed.

Conclusion:

These data support that Mg plays a crucial role in the intracellular dynamics of Ca, with an increased Ca:Mg ratio, leading to increased oxidative stress and increased migration of colon cancer cells in vitro (and possibly their metastatic potential).

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P13

Purpose: Magnesium (Mg) is an important micronutrient involved in various cell functions. Systemic Mg homeostasis mainly depends on the concomitant action of intestine and kidney, for its uptake and reabsorption, respectively. A significant proportion of patients treated with Cetuximab (CTX), a monoclonal antibody targeting the epidermal growth factor receptor (EGFR), develops a mild to severe hypomagnesemia. This effect has been ascribed to a specific downregulation of the TRPM6 Mg channel that occurs in kidney epithelial cells. Given the importance of the intestine in maintenance of Mg homeostasis, we investigated: 1) whether CTX could also affect Mg homeostasis in the gut, 2) whether magnesium supplementation could impact on CTX efficacy.

Materials and methods:

We used a colon epithelial cell line (CaCo2) to assess the effects of CTX, with or without EGF stimulation or Mg supplementation on Mg influx, viability and migration. Mg influx was evaluated by live cell imaging of Mag-Fluo-loaded cells. Cell viability and migration were evaluated by MTT tests and scratch assays, respectively.

Results: CTX significantly reduced magnesium influx, while EGF stimulation doubled it. Cetuximab inhibition of magnesium influx was rescued by EGF. EGF stimulation also enhanced wound healing capacity, while cetuximab reduced it. In CTX-treated cells, both Mg or EGF supplementation overrode the inhibitory effect of CTX on wound healing capacity. Mg supplementation did not affect CTX EC50.

Conclusion:

CTX reduces magnesium uptake and cell migration of colon epithelial cells. Mg supplementation or EGF treatment rescues these effects. Our data suggest that Mg supplementation may represent a safe and cost-effective strategy to promote mucosal healing without impairing cetuximab efficacy.

Cetuximab Impacts on magnesium uptake in the colon

Giuseppe Pietropaolo¹, Daniela Pugliese², Francesca Luongo¹, Federica I. Wolf¹ and Valentina Trapani¹ ¹ Istituto di Patologia Generale, Università Cattolica del Sacro Cuore, Fondazione Policlinico Universitario "Agostino Gemelli" IRCCS, Rome, IT ² IBD Unit, Presidio Columbus Fondazione Policlinico Universitario "Agostino Gemelli" IRCCS, Università Cattolica del Sacro Cuore, Rome, IT

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HERMES PHARMA IS THE MAGNESIUM EXPERT

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  IMS 2019 fees shown are in US DOLLARS (US$) and in EURO (€) -You are free to choose your currency. (**) As a student, you are kindly requested to show your student card.

  Congress kit (badge, pen, program/abstract book and bag) • Access to the scientific sessions • Access to the commercial exhibition • Luncheons on Wednesday March 20 th and Thursday March 21 st • Coffee/Tea Break around Posters on Wednesday March 20 th and on Thursday March 21 st • Coffee and Light Lunch around Posters on Friday March 22 nd • Certificate of attendance

  How to reach Old Ebbitt Restaurant from Bethesda Station METRO RED LINE (25 minutes): Metro direction GLENMONT -Stop at METRO CENTER STATION and follow the indications on the map (5 minutes walk). Out the subway, take the West direction on G St NW, go straight, then turn left on 15th St NW. Ebbitt Grill is Washington's oldest saloon, just steps from The White House and museums downtown. It was a favorite of Presidents Grant, Cleveland, Harding, and Theodore Roosevelt and is still a popular meeting spot for political insiders, journalists, celebrities and theater-goers.

  The George Washington University School of Medicine, Dept. of Biochemistry & Molecular Medicine; Dasman Diabetes Institute (DDI), and IntraCellular Diagnostics Inc.

  Gudermann1, Sandra Voringer1, Tobias Siekmann1, Susanna Zierler1, Vladimir Chubanov1, Susanne Muehlich 1,2 1 Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, LMU Munich, Germany 2 Department of Chemistry and Pharmacy, Molecular and Clinical Pharmacy, University of Erlangen, Germany Biographical Sketch Distinguished James McGill Professor in the Department of Biochemistry at McGill University in Montreal, Canada. He funded and directed the Rosalind and Morris Goodman Cancer Research Centre from 2000 to 2012. A fellow of the Royal Society of Canada, Dr. Tremblay's laboratory focuses on characterizing the function and regulation of several members of the Protein Tyrosine Phosphatase (PTP) gene family using both biochemical and genetic approaches. He has several translational research programs towards clinical applications of PTP inhibitors in the fields of immunotherapy and cancer. Within international collaborations, he has published key findings on the interaction of the CNNMs and PTP4As gene sub-families and their relationships between magnesium and cancer. Contact: michel.tremblay@mcgill.ca 46 XV International Magnesium Symposium -NIH -Bethesda, USA -March 20 th -22 nd , 2019

( 1 ) 1

 11 Wabakken T, Rian E, Kveine M, Aasheim HC. The human solute carrier SLC41A1 belongs to a novel eukaryotic subfamily with homology to prokaryotic MgtE Mg2+ transporters. Biochem Biophys Res Commun. 2003;306(3):718-24.(2) Kolisek M, Nestler A, Vormann J, Schweigel-Rontgen M. Human gene SLC41A1 encodes for the Na+/Mg 2+ exchanger. Am J Physiol Cell Physiol. 2012;302(1):C318-26. (3) Sahni J, Scharenberg AM. The SLC41 family of MgtE-like magnesium transporters. Mol Aspects Med. 2013;34(2-3):620-8. (4) Mastrototaro L, Smorodchenko A, Aschenbach JR, Kolisek M, Sponder G. (2016) Solute carrier 41A3 encodes for a mitochondrial Mg 2+ efflux system. Sci Rep. 6:27999. (5) Kolisek M, Zsurka G, Samaj J, Weghuber J, Schweyen RJ, Schweigel M. (2003) Mrs2p is an essential component of the major electrophoretic Mg 2+ influx system in mitochondria. EMBO J. 22(6):1235-44. (6) Kuramoto T, Kuwamura M, Tokuda S, Izawa T, Nakane Y, Kitada K, Akao M, Guénet JL, Serikawa T. (2011) A mutation in the gene encoding mitochondrial Mg²+ channel MRS2 results in demyelination in the rat. PLoS Genet. 7(1):e1001262. Gerhard Sponder Institute of Veterinary Physiology, Veterinary Medicine, Free University of Berlin, Berlin, Germany Biographical Sketch Deletions or mutations in the MAGT1 gene cause defects in N-linked glycosylation of cellular glycoproteins and are responsible for glycosylation disorders Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, USA 2 Laboratory of Molecular Diagnosis, Centre for Human Genetics, KU Leuven, Belgium 3 Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, USA

  born in Chicago, Illinois on December 1, 1955. He attended the Johns Hopkins University and graduated with a Bachelor of Arts in Natural Sciences in 1977. He then attended Washington University in St. Louis, Mo. and obtained his Doctor of Medicine (M.D.) in 1981. He carried out clinical and research training at the University of Iowa from 1981-1985. He was then a Research Fellow at the Whitehead Institute for Biomedical Research at Massachusetts Institute of Technology with an adjunct appointment at Harvard Medical School. During this time, he carried out molecular biology research under the mentorship of Nobel laureates David Baltimore and Philip Sharp. He was then appointed Section Chief in the National Institute of Allergy and Infectious Diseases, National Institutes of Health from 1989 to the present, directing research on T-lymphocyte regulation, HIV-1, and genetic diseases of the immune system. He has served on the editorial boards for the European Journal of Immunology, the Journal of Experimental Medicine, Science magazine, and Biology Direct. He is an Adjunct Professor of Pathology at the University of Pennsylvania School of Medicine, and a Visiting Fellow at Cambridge University. He has founded or co-founded several joint research programs including the NIH-Oxford-Cambridge Biomedical Research Scholars, the NIH-University of Pennsylvania Immunology Program, the NIH-Marshall Scholars, the NIH-Rhodes Scholars, the National M.D./Ph.D. partnership program, and the NIH-Institut Pasteur Infectious Disease and Immunology Program. Dr. Lenardo has published over 200 scholarly works and holds a number of medical patents. He discovered the propriocidal mechanism of immune regulation and his work has defined several genetic diseases of the immune system including the Autoimmune Lymphoproliferative Syndrome, Caspase-8 deficiency syndrome, and X-linked magnesium deficiency with EBV and neoplasia (XMEN) disease. He is currently the Director of the Clinical Genomics Program and Chief of the Molecular Development of the Immune System Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health. Among his honors and awards, he is Officer of the Most Excellent Order of the British Empire (O.B.E.), conferred by Queen Elizabeth II, March, 2006 and a Fellow of the American Association for the Advancement of Science and the American Academy of Arts and Sciences. He is married to Lesley-Anne Furlong, M.D. and has two sons, Brian and Timothy. Contact: Sanofi, Gentilly, France 2 Statistics, Sanofi, Gentilly, France 3 Unité de Nutrition Humaine, INRA, Université Clermont Auvergne, Clermont-Ferrand, France ⁴ Nutrition and Behaviour Group, School of Psychology, University of Leeds, Leeds, United Kingdom ⁵ Contract Research and Saliva Lab, Daacro, Trier, Germany ⁶ Clinical Pharmacology Department, CHU, Université Clermont Auvergne, Clermont-Ferrand, France

Fig. 2 Fig. 1

 21 Fig.2 Fig.1

  Stella Lucia Volpe, PhD, RDN, ACSM-CEP, FACSM, is Professor and Chair of the Department of Nutrition Science at Drexel University, Philadelphia, PA. Her degrees are in both Nutrition and Exercise Physiology; she also is an American College of Sports Medicine (ACSM) Certified Clinical Exercise Physiologist® and a Registered Dietitian Nutritionist. Dr. Volpe's research focuses on obesity and diabetes prevention using traditional interventions, mineral supplementation, and by altering the environment to result in greater physical activity and healthy eating.

Department of Nutrition Sciences, Drexel University, Philadelphia, USA Magnesium and athletic performance She also conducts research on athletes of all levels, from recreational to professional. Prior to beginning her faculty appointment at Drexel University, Dr. Volpe was on faculty at the University of Pennsylvania, and previous to that, she was on faculty at the University of Massachusetts Amherst. Dr. Volpe is Editor-in-Chief of Current Nutrition Reports. She is an associate editor of ACSM's Health & Fitness Journal® and the Translational Journal of ACSM. Contact: SLV43@drexel.edu

andre.mazur@inra.fr

	Director of the Human Nutrition Unit, INRA and University of Clermont Auvergne, Clermont-Ferrand, France, edi-tor-in-chief of the "Magnesium Research"-Official Journal of the International Society for the Development of Re-search on Magnesium. His lab is involved in research intended to provide knowledge of the mechanisms by which nutrients, especially micronutrients, contribute to the prevention of age-related diseases. His research on magne-sium has been focused on its role in inflammation and the CVD risk as well as on magnesium status assessment. Contact:

Serge Hardy 1 , Noriko Uetani 1 , Elie Kostantin 1,2 , Michel L. Tremblay 1,2 1

Goodman Cancer Research Centre, McGill University, Montreal, Quebec, Canada 2 Department of Biochemistry, McGill University, Montreal, Quebec, Canada

Mg 2+ as a second messenger in early developmental stages of neurons Magnesium, skeletal muscle health, sarcopenia, osteoporosis and fracture risk

  Center for Biosciences and Informatics, School of Fundamental Science and Technology, Graduate School of Science and Technology, Keio University, Yokohama, Japan Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Taiwan

OC01 Measures of muscle magnesium status from 31P magnetic resonance spectroscopy are associated with age, sex, and knee extension strength

  Dept. of Biomedical and Clinical Sciences L. Sacco, University of Milano, ItalyDonnie Cameron 1,2 , Ailsa Welch 2 , Fatemeh Adelnia 1 , Christopher M. Bergeron 1 , David A.Reiter 1,3 , Nicholas A. Brennan 1 , Kenneth W. Fishbein 1 , Richard G. Spencer 1 , Luigi Ferrucci 1

	1 National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
	2 Norwich Medical School, University of East Anglia, Norwich, UK
	3 Emory University School of Medicine, Atlanta, GA, USA

Global human Mg nutrition: need and supply

  Using FAO food supply data and food Mg values from the USDA-NAL database, Kumssa et al., 2015 derived the 1991-2011 per capita human dietary Mg global supply and compared it with the UN/FAO human nutritional Mg requirements, weighted for global age distribution. This analysis showed that the unprocessed global Mg Supply easily meets human global Mg need with a small risk of dietary Mg deficiency. However, the UN/FAO Mg RDA is a low estimate of human Mg need, not taking into account the global trend of rising body weights, possibility of CLMD with the physiological transfer of Mg body stores (mostly bone) during suboptimal Mg intakes, nor impacts of stress on Mg requirement. Additionally, food processing losses of Mg can be substantial.

	Andrea Rosanoff
	Center for Magnesium Education & Research LLC
	Purpose: Does the global Mg Supply meet the nutritional Mg need of the growing and aging global human po-
	pulation?
	Materials & Methods:

Monitoring the serum Ca/Mg ratio in response to magnesium supplementation

  Rebecca Costello¹, Forrest Nielsen², Andrea Rosanoff³, Michael Plesset³ and Ronald Elin⁴

	¹ NIH Office of Dietary Supplements, Bethesda, MD
	² USDA Grand Forks, ND
	³ Center for Magnesium Education and Research, Pahoa, HI
	⁴ University of Louisville, KY

P01 Magnesium and depression in patients at risk of suicide

  Emily Young¹, Andrea Rosanoff², Ph.D., Rebecca Costello², Ph. D., Michael R. Plesset², Bernadette P. Marriott, Ph. D.¹

	Ca/Mg Ratio by Group	N	Baseline	Depletion		p-value (baseline vs. repletion)
	127	13	4.63 ± .218	4.98 ± .282	5.22 ± .270	.00002
	132	13	4.45 ± .036	4.58 ± .389	4.74 ± .269	.0004
	135	13	4.53 ± .256	4.34 ± .310	4.39 ± .312	.074
	Normal QTc	28	4.55 ± .314	4.59 ± .457	4.71 ± .471	.030
	Increased QTc > .450 msec	11	4.52 ± .220	4.75 ± .295	4.95 ± .301	.0004
						79

Magnesium and insulin stimulate glucose uptake in differentiated bovine adipocytes

  . Jurek¹, M.A. Sandhu 1, 2 , S. Trappe¹, M. Kolisek 1,3 , G. Sponder 1 and J.R.Aschenbach 1

	¹ Freie Universität Berlin
	² PMAS-Arid Agriculture University, Rawalpindi, Pakistan
	³ Comenius University Bratislava, Slovakia

S

XV International Magnesium Symposium -NIH -Bethesda, USA -March 20 th -22 nd , 2019

Medical University of South Carolina, Charleston, SC, USA ² Center for Magnesium Education and Research, Pahoa, HI, USA

ACKNOWLEDGEMENTS

XV International Magnesium Symposium -NIH -Bethesda, USA -March 20 th -22 nd , 2019 XV International Magnesium Symposium -NIH -Bethesda, USA -March 20 th -22 nd , 2019

INFORMATION

XV International Magnesium Symposium -NIH -Bethesda, USA -March 20 th -22 nd , 2019

XV International Magnesium Symposium -NIH -Bethesda, USA -March 20 th -22 nd , 2019 18 Associations of dietary and urinary magnesium, calcium and their ratio with blood pressure: intermap

Magnesium -impact of food processing on the bioavailability of this shortfall nutrient

Roger Clemens 1 , Peter Pressman 21 USC School of Pharmacy, Los Angeles, CA USA 2 Daedalus Foundation, Mt. Vernon, VA 22121 USA Purpose: Magnesium is one of the many shortfall nutrients. This nutrient is central in cellular energetics and an array of metabolic systems, including those involved in hepatic detoxification of xenobiotics. This issue is particularly important among an older adult (51 years) population which is often associated with the stress of polypharmacy. Little is known about impact of various forms of food processing (e.g., thermal and non-thermal) and Mg bioavailability.

Materials and methods:

The bioavailability of Mg in a variety of food matrices and following several food processing conditions were evaluated. The apparent uptake and activity of Mg among human subjects and in animal models were compared with analytical data from the identified commercial foods.

Results: Preliminary data from rat hepatocytes and microsomal membranes suggest inadequate Mg intake may reduce glucuronidation via decreased UDP-glucuronyl transferase activity, while overt presentation of Mg deficiency was not observed. Additional data suggest numerous nutrient interactions with dietary Mg, such as Ca, protein and dietary fiber, may influence the uptake and subsequent impact of Mg-related biological activities. This intake may also be affected by its influence on a sensory quality, such that Mg salts are typically bitter. On the other hand, these divalent salts may provide several technical effects in processed foods, including reducing syneresis and minimizing biofilm formation.

Conclusion:

Magnesium is a cofactor in more than 300 enzyme systems that regulate diverse biochemical reactions in the body. Current data indicate dietary intake of Mg is insufficient. These data which rely on analytical analysis are insufficient to adequately assess Mg status. Magnesium assessment by serum Mg levels does not reflect its metabolic status. Our incomplete understanding of Mg in food suggest some components in plant-based diets known to reduce mineral uptake may actually be decreased following food processing.

Regulation of and by the murine TRPM7 channel-kinase

Pavani Beesetty 1 , Tetyana Zhelay 1 , Taku Kaitsuka 2 , Masayuki Matsushita 3 and J. Ashot Kozak TRPM7 is a ubiquitously expressed dual function cation channel-protein kinase. Mg 2+ and other divalent metal cations are both permeant ions and regulators of TRPM7 channels. TRPM7 kinase, belonging to eEF-2 kinase family, is regulated by these cations as well but with a diverging profile. The relationship between the kinase and channel activities of this protein has been the focus of numerous studies yet its details remain unclear. We showed that TRPM7 can autophosphorylate at serine/threonine residues without noticeably altering channel activity. Moreover, point mutations abolishing kinase activity leave the channel function largely intact, demonstrating that kinase activity and autophosphorylation are not necessary for ion conduction. We investigated the consequences of kinase inactivation in a mouse model where K1646R kinase-dead (KD) variant replaced wildtype TRPM7. The spleens of the mutant animals were larger and evidence of extramedullary hematopoiesis was found. Proliferation and enlargement were significantly reduced in KD mouse T cells in response to anti CD3/CD28 stimulation. Store-operated calcium entry, required for efficient proliferation, was diminished. TRPM7 protein expression was upregulated in activated T cells of both WT and KD mice. Effects of kinase inactivation in lymphocytes did not depend on extracellular Mg 2+ and Ca 2+ concentrations, however, suggesting that Mg 2+ /Ca 2+ influx was not responsible. The mechanism of channel inhibition by cytosolic Mg 2+ has remained a mystery since its discovery. Using voltage-sensitive phospholipid phosphatase expression and site-directed mutagenesis of TRPM7, we investigated the dependence of channel sensitivity to these cations on phosphoinositides by patch clamp electrophysiology. We found that in PIP2-depleted cells, Mg 2+ and proton inhibition of the channels was more effective. Point mutations in the channel drastically reducing channel sensitivity to Mg 2+ , also decreased its sensitivity to polyamines and protons and PI(4,5)P2 depletion. We conclude that inhibition by Mg 2+ reflects sequestration of plasma membrane PI(4,5)P2, the necessary cofactor for channel activation.

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Magnesium acetyltaurate: a prospective drug candidate for retinal neuroprotection in glaucoma

Igor Iezhitsa 1,2* , Renu Agarwal¹, Lidawani Lambuk¹, Natasha Najwa Nor Arfuzir¹, Azliana Jusnida Ahmad Jafri¹, Puneet Agarwal³, Alexander Spasov², Alexander Ozerov² Endothelin-1 (ET-1) enhances glutamate-induced retinal cell death, possibly through ET receptors and ET-1 may act synergistically with glutamate to damage retinal neurons. Glutamate-induced neurotoxicity is triggered by Ca 2+ influx into neurons by NMDA receptors and ET-1 is known to increase the intracellular Ca 2+ concentration in glial and neuronal cells. Additionally ET-1 specifically stimulates the efflux of glutamate via ET receptors from astrocytes, suggesting that ET-1 exacerbates neurodegeneration. Owing to that, several studies have been done to investigate therapies for RGC protection by targeting ET-1 and NMDA receptors. Accordingly, NMDA and/or ET receptor antagonists have been suggested to inhibit excitotoxicity in RGCs and to delay progression of visual loss in glaucoma.

Purpose:

The purpose of the present study was to examine the potential of neuroprotective effect of Mg acetyltaurate (MgAT) on RGC death induced by NMDA and ET-1. The choice of MgAT was due to structural combination of magnesium (Mg) and taurine which together were expected to provide neuroprotection through multiple mechanisms such as inhibition of ET1 effect, antagonism of NMDA receptors, and antioxidant properties.

Materials and methods:

In two series of experiments (ET1 and NMDA series) rats were divided into 5 groups of 6 rats each and were given intravitreal injections. Group 1 (PBS group) was injected with vehicle; group 2 (NMDA/ET1 group) was injected with either NMDA or ET1 while groups 3 (pre-treatment -), 4 (co-treatment) and 5 (post-treatment) were injected with MgAT, 24 hours before, in combination or 24 hours after either NMDA or ET1 injection. NMDA, ET1 and MgAT were injected in PBS at doses 160 nmol and 320 nmol, respectively. Seven days after intravitreal injection, the histological changes in the retina were evaluated using haematoxylin & eosin (H&E) staining. The extent of retinal cell apoptosis was assessed by TUNEL assay and Caspase-3 immunohistochemical staining.

Results:The estimation of neutrophic factor, oxidative and nitrosative stress, pro/anti-apoptotic factors and caspase-3 activity in retina was done using enzyme-linked immunosorbent assay (ELISA) technique. The morphometric measurements on H&E staining showed reduction in number of ganglion cells in NMDA/ET-1 group compared to the MgAT pre-and co-treated groups. Similar results were observed in TUNEL and Caspase-3 staining. The results were further corroborated by the estimation of neutrophic factor, oxidative stress, pro/anti-apoptotic factors and caspase-3 activity in retina. In conclusion, our current study revealed that pre-treatment with intravitreal MgAT prevents RGC apoptosis induced by NMDA/ET1.

Conclusion:

Overall, our data demonstrated that the pretreatment with MgAT was more effective that co-and post-treatment. Protective effect of MgAT was associated with activation of BDNF-related neuroprotective mechanisms and reduction of retinal oxidative and nitrosative stress.

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XV International Magnesium Symposium -NIH -Bethesda, USA -March 20 th -22 nd , 2019

Dietary magnesium alleviates murine colitis through upregulation of TRPM6 and modulation of intestinal microbiota

Valentina Trapani 1 , Valentina Petito², Andrea Quagliariello³, Giuseppe Pietropaolo¹, Sofia Reddel³, Federica Del Chierico³, Lorenza Putignani 3,4 , Antonio Gasbarrini 2,5 , Franco Scaldaferri 2,5 and Federica I. Wolf Purpose: Magnesium is mainly absorbed through the intestine. Therefore, chronic inflammation in the intestine is likely to result in a magnesium deficit, which could in turn exacerbate inflammation. The aim of the present study was to assess whether dietary magnesium availability could affect the course of inflammatory bowel disease (IBD).

Materials and Methods:

The correlation between magnesemia and IBD activity was examined in 30 patients. The effect of dietary magnesium modulation was evaluated in a murine model of dextran sodium sulphate (DSS)-induced colitis. The role of the TRPM6 channel was investigated in a panel of colon cancer cell lines.

Results:

In IBD patients, serum magnesium levels inversely correlated with disease activity and inflammatory markers. In mice, magnesium deficiency aggravated DSS-induced colitis, and viceversa colitis severely compromised intestinal magnesium absorption due to mucosal damage and reduction in TRPM6 expression. On the other hand, Mg supplementation resulted in better restoration of mucosal integrity and channel expression upon DSS challenge. Notably, distinctive gut microbiota profiles were associated with inflammation and with a magnesium-rich diet. In vitro, TRPM6 expression and function was strictly associated with epithelial cell functions.

Conclusion:

Our results highlight the importance of evaluating and correcting magnesemia in IBD patients. The murine model suggests that Mg supplementation may represent a safe and cost-effective strategy to reduce inflammation and restore mucosal function, as well as to modulate gut microbiome. We confirm that TRPM6 expression and function in the colon is essential for systemic magnesium homeostasis and health.

Materials and Results:

Treatment with cART (Truvada+atazanavir/ritonavir) up to 18 weeks, induced significant hypomagnesemia (-25%, p<0.01) in the HIV-Tg rats along with significant (p<0.05) renal dysfunction (increased plasma creatinine & urea), elevated plasma 8-isoprostane (265% increase, p<0.01), RBC GSSG 2-3 folds along with a 3-fold (p<0,01) increased basal neutrophil superoxide production; plasma 3-nitrotyrosine (NT) also increased 3.5-fold in the HIV-Tg rats. In association, hepatic master transcription factor for antioxidant defense, Nrf2 (nuclear erythroid-related factor-2) expression (by real-time RT-PCR) was down-regulated 50-75% (p<0,01) along with altered down-stream related expression of heme oxygenase-1 (HmOX-1) and glutathione-S-transferase (GST) in the HIV-Tg rats; however, iNOS and TNFα mRNAs were increased 2-& 4-fold (p<0.01). Prominent renal and ventricular NT staining was observed in HIV-Tg+cART rats; echocardiography detected moderate but significant decreases in cardiac systolic (Fractional Shortening. -17%, p<0.05, and diastolic (E/A, -26%,p<0.01) function. Mg-supplementation (6-fold in the diet), substantially prevented (p<0,05) the increased levels of 8-isoprostane, RBC-GSSG, plasma NT and suppressed neutrophil activation. Striking, Mg-supplementation also restored (p<0.01) the expression of Nrf2, HmOX-1 and GST in HIV-Tg rats; both iNOS and TNFα up-regulations were blunted. In association, renal and cardiac NT staining was substantially (p<0.05) reduced; both renal dysfunction and decreased cardiac systolic, diastolic function were attenuated 60-70% (p<0.05). Purpose: Magnesium has an important role in hypertension (1,2). According to the results of the MACH study additional magnesium orotate therapy has shown a positive effect on life expectancy and quality of life in patients with severe forms of heart insufficiency [START_REF] Stepura | Magnesium orotate in severe congestive heart failure (MACH)[END_REF]. Both magnesium or orotate can be cardioprotective.

Conclusions

Material and methods:

In the presented data here additional magnesium orotate therapy was tested in 11 patients with hypertensive heart disease NYHA III-IV as compared to 10 patients with hypertensive heart disease NYHA II-IV as controls. Additional magnesium orotate therapy was 4500 mg magnesium orotate daily for one week.

Results: NTproBNP levels decreased significantly in the magnesium orotate group versus controls (figure) (p< 0.01 ). Under therapy quality of life improved significantly as well. Kidney function remained stable in the normal range (4).

Conclusion:

An additional therapy with magnesium orotate is of benefit in hypertensive heart disease.

Incidence of hypomagnesemia and hypermagnesemia in a university hospital

A. Catalano, D. Chilà, F. Bellone, N. Morabito, S. Loddo, S. Benvenga, F. Corica

Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy

Purpose: Magnesium is the fourth most abundant cation circulating in the body involved in a number of fundamental processes such as glycemic control, muscle contraction, energy production, bone metabolism. Magnesium disorders are often underestimated in the clinical practice. The aim of our study was to evaluate the incidence of hypomagnesemia and hypermagnesemia in hospitalized patients.

Materials and methods:

This retrospective study was based on data from laboratory tests of all inpatients whose serum levels of magnesium were measured between January 1, 2015 and December 31, 2017. Measurements of magnesium were carried out by a single centralized laboratory. Hypomagnesemia was defined by serum magnesium levels <1.5 mg/dl and hypermagnesemia by serum calcium levels> 3.8 mg/dl.

Results: A total of 11,469 subjects were considered. Hypomagnesemia accounted for 8.58% (n=985) and hypermagnesemia for 1.58% (n=182) of recruited subjects over the entire observation period. The incidence of hypermagnesemia increased from 1.38% in 2015 to 1.93% in 2017. The highest incidence of hypomagnesemia (5.27%, n=604) was found in subjects over65yr, while a lower incidence was observed in patients aged 19-65yr and<19yr (2.67%, n=307 and 0.64%, n=74, respectively). Incidence of hypermagnesemia showed no differences over time and according to age.

Conclusion:

Magnesium disorders and particularly hypomagnesemia are frequently observed in hospitalized elderly patients. Physicians have to check for magnesium levels because its disturbances may be of potentially reversible consequences for human health if adequately treated.

86

P08

XV International Magnesium Symposium -NIH -Bethesda, USA -March 20 th -22 nd , 2019

Stressed cerebral organoids: can magnesium help? Alessandra Cazzaniga, Valentina Romeo, Laura Locatelli, Roberta Scrimieri, Sara Castiglioni, Jeanette A.M. Maier Dipartimento di Scienze Biomediche e Cliniche L. Sacco, Università di Milano, Milano I-20157, Italy Purpose: Several studies have documented an association between magnesium and depression, anxiety and stress, even though the mechanistic pathways are largely unknown. Magnesium (Mg) increases the availability of GABA, the primary inhibitory transmitter in the CNS, and inhibits the activity of the NMDA receptor, which is the receptor for the excitatory neurotransmitter glutamate.

Materials and methods:

A novel approach to study the effects of Mg in stress, anxiety or depression, is represented by the use of human mini-organoids. These are generated from induced human pluripotent stem cells (iPS) cells. Mini-brains will be exposed to different concentrations of magnesium salts with or without stress mediators (i.e. adrenalin, cortisol). The levels of glutamate, GABA and their receptors will be measured.

Results: Human Mini-brain organoids are embedded in droplets of a gelatinous protein mixture within a spinning bioreactor, providing the structural support and the nutrient/oxygen exchange that allows growth of organoids up to 4 mm in diameter. Retinoic acid, which is critical for cortical neurogenesis, is added to accelerate development. Neurons appear after 10 days, and in about 30 days defined brain regions form. Mini-brain organoids will be generated using media with various concentration of Mg in the presence or not of stress mediators

Conclusion:

The human mini-brain organoids is an innovative experimental model to study neural networks in human brain and, therefore, might highlight the molecular mechanisms underlying Mg involvement in stress, anxiety and depression.

87

P09

XV International Magnesium Symposium -NIH -Bethesda, USA -March 20 th -22 nd , 2019

Magnesium deficiency syndrome

Corneliu D. Zeana, MD, PhD UMF Carol Davila Bucharest and AIS Clinic and Hospital Bucharest, ROMANIA Magnesium is one of the most important mineral in biology. More than 300 enzymes are activated by magnesium in humans. During the last hundred years and especially within the last decades, the Magnesium input dropped dramatically, to more than half of the quantities ingested before. Responsible factors for this reduction of magnesium concentration in the food are: industrialization of the agriculture, especially excessively use of chemicals, irrigations, acid rains, followed by the semiindustrial food preparation We entered the era of generalized magnesium deficit.( 2) As a consequence of the magnesium carence, beyond the limits of the biological compensatory mechanisms, some manifestations expressing the magnesium deficit become manifest: in the vegetal world (some trees have pale leafs, even yellow, due to less than normal chlorophyle content), animal ( cow tetany) and humans. Jean Durlach was the first that in established a link between magnesium deficit, latent tetany and mitral valve prolapse (Durlach syndrome) (1). We describe a new syndrome manifest in the children of the magnesium deficient mothers suffering from spasmophilia and mitral valve prolapse (Durlach syndrome). These women are magnesium looser, meaning that they have a diminished capability of conserving the magnesium in the body. This trait is probably inherited because cluster of such cases are encountered in these families, especially spasmophylia , mitral valve prolapse and stress sensitivity. Their children have been followed by us from the birth to the adulthood. They developed generalized convulsions during the first year of age, rarely after this age, very few up to three years, and no longer manifest thereafter so that epilepsy was ruled out. Convulsions were triggered by high fever, brisk noise, but also without identifiable cause. These children presented somatic stigma of magnesium deficit, especially chest deformities: plat thorax, flat dorsal curvature, rarely funnel chest. In the late childhood and adolescence they develop spasmophylic episodes. Palpitations are a common complaint. Mitral valve prolapse clearly visualized by echocardiography is evident but rarely of severity. Later, in adulthood, urolithiasis is frequent, with or without urinary stones elimination. Three cases with the above exposed manifestations have been described: Two women, aged 42 and 44 respectively and one male, 38 years old. Satisfactory results are obtained with magnesium supplementation of log haleine. In the majority of cases, under magnesium supplementation the mitral valve prolapse is ameliorated to the resumption of the normal aspect of the valve.

Summary

A new syndrome expressing the magnesium deficiency is described. The association of spasmophilia, mitral valve prolapse, generalized convulsions in infancy, skeleton deformities, heart arrhythmias and urolithiasis defines this syndrome. Familial predisposition is notable. Good results are obtained by magnesium supplementation of long duration.

Involvement of CaSR, claudin-14 and 16 in the development of hypermagnesiuria associated with tubulo-interstitial nephropathy

Taisuke Shimizu¹, Kaori Takayanagi 1,2 , Akira Kurosawa¹, Masaaki Terao¹, Hiroaki Hara¹, Takatsugu Iwashita¹, Maiko Yamasaki¹, Yumiko Nakamura¹, Mariko Sato¹, Yu Shimozato¹, Akira Ikari³, Hajime Hasegawa¹ ¹ Department of Nephrology and Hypertension, Saitama Medical Center, Saitama Medical University, Kawagoe, Saitama, Japan ² Ishikawa Kinenkai, Kawagoe Ekimae Clinic, Saitama, Japan ³ Laboratory of Biochemistry, Gifu Pharmaceutical University, Gifu Purpose: Hypermagnesiuria is well known clinical feature of tubulo-interstitial nephropathy (TIN), and would be a diagnostic tool for TIN. We studied the changes in the expression of renal magnesium transporting molecules with the development of TIN in rats with unilateral ureter obstruction (UUO).

Materials and methods: Ureter-ligated kidney was sampled at day-0 (control), day-1 (early phase) and day-7 (late phase). The development of TIN was assessed by immunohistochemistry and the real-time PCR of fibrosis-related genes (MCP-1,TGF-β) . The respective expressions of claudin-10, 14, 16, 19, and transient receptor potential (TRP) M6 as magnesium-transporting molecules were also studied. The expression of calcium sensing receptor (CaSR) as an inhibitory regulator of claudin-14 was additionally studied.

Results:

The gene expression of claudin-16 was decreased in the late phase of UUO (100.2 ± 2.9% at day-0, 90.3 ± 6.3% at day-1, 36.4 ± 1.6% at day-7) which was consistent with the increased urine magnesium excretion (FEMg: 3.13±0.81 at day-0, 4.72±0.54 at day-1, 10.7±0.81% at day-7). Immunohistochemistry showed an apparent reduction of the immunoreactivity of claudin-16 in the late phase. The expression of TRPM6 was reduced even in the early phase. The immunohistochemistry and gene expression of MCP-1 and TGF-β showed that TIN was not apparent in the early phase but was significant in the late phase. The density of peritubular capillaries was diminished in the late phase but not in the early phase. Expression of claudin-14 and CaSR was up-and down-regulated, respectively.

Conclusion:

Our findings may indicate that the hypermagnesiuria in TIN is principally caused by the dysfunction of magnesium reabsorption in the thick ascending limb of Henle resulting from a significant decrease in the claudin-16 expression. The down-regulation may be closely related to the development of TIN through CaSR-claudin-14-claudin-16 regulatory network.

89

P11

XV International Magnesium Symposium -NIH -Bethesda, USA -March 20 th -22 nd , 2019

A focus on magnesium in epilepsy research and treatment -a review

Marija Stanojević 1,2 , Srdjan Lopicic¹, Jelena Nesovic Ostojic¹, Svetolik Spasic¹, Sanjin Kovacevic¹, Vladimir Nedeljkov¹, Milica Results: Magnesium has multiple neuroactive actions (analgetic, antimigrenous, antidepressant, anxiolytic, neuroprotective, anticonvulsive). Mg 2+ exerts an overall stabilizing effect on nerve cell function. Neuronal Mg 2+ requirements are high and its level higher in the cerebro-spinal fluid (CSF) then in the serum. Magnesium status is usually assessed by measuring the total serum Mg 2+ level (tMg 2+ ); however, serum level of ionized Mg 2+ (iMg 2+ ) is considered to be a better indicator. Magnesium deficiency has epileptogenic effect. Magnesium deprived diet induces seizures in experimental animals. In humans hypomagnesiemia increases seizure frequency. In pharmacoresistant epilepsy (PhRE) hypomagnesiemia increases the risk of sudden unexpected death from epilepsy. In epilepsy patients iMg 2+ levels are found to be low in serum and CSF. Low serum iMg 2+ /tMg 2+ ratio was found interictally in patients with PhRE. In animal models of epilepsy Mg 2+ shows antiepileptic effect. In humans, anticonvulsant Mg 2+ effect is clinically used to control seizures in eclampsia, uremia, porphyria and hypomagnesiemia. Magnesium infusion can also help control refractory status epilepticus. The intact blood-brain barrier normally prevents Mg 2+ penetration into the brain. Its increased permeability in seizures permits Mg 2+ loss by leakage from the interstitial brain fluid, but also allows for Mg 2+ level in the brain to be restored by i.v. treatment. Oral magnesium supplementation has been reported to help reduce seizure frequency.

Conclusion:

More research studies focusing specifically on Mg 2+ in basic and clinical epileptology are needed to further enlighten its role in the underlying pathophysiological mechanisms and adequately evaluate the promising benefit of magnesium supplementation in epilepsy, especially for the PhRE cases.