Showing papers in "Magnesium Research in 2011"
TL;DR: The aim of this review is to revisit current knowledge concerning the contribution of magnesium to tumorigenesis, from transformed cells to animal models, and ending with data from human studies, to disclose whether a simple and inexpensive intervention to optimize magnesium intake might be helpful in the prevention and treatment of cancer.
Abstract: A complex relationship links magnesium and cancer. The aim of this review is to revisit current knowledge concerning the contribution of magnesium to tumorigenesis, from transformed cells to animal models, and ending with data from human studies. Cultured neoplastic cells tend to accumulate magnesium. High intracellular levels of the cation seem to confer a metabolic advantage to the cells, contribute to alterations of the genome, and promote the acquisition of an immortal phenotype. In magnesium-deficient mice, low magnesium both limits and fosters tumorigenesis, since inhibition of tumor growth at its primary site is observed in the face of increased metastatic colonization. Epidemiological studies identify magnesium deficiency as a risk factor for some types of human cancers. In addition, impaired magnesium homeostasis is reported in cancer patients, and frequently complicates therapy with some anti-cancer drugs. More studies should be undertaken in order to disclose whether a simple and inexpensive intervention to optimize magnesium intake might be helpful in the prevention and treatment of cancer.
113 citations
TL;DR: It is hypothesized that high levels of magnesium might alter the intracellular concentration of various cations - among which calcium - by competing for the same transporters and contribute to bone disease.
Abstract: Several studies in humans indicate that both high and low concentrations of magnesium have harmful effects on bone metabolism and homeostasis. However, little is known about the effects of different concentrations of magnesium on bone cells. Considering that 1 mM is the physiological concentration of extracellular magnesium for cultured cells, in our experimental model we exposed osteoblast like SaOS-2 cells and normal human osteoblasts to low (0.1 mM) and high (5.0 mM) concentrations of magnesium. We found that high concentrations of magnesium markedly inhibited the deposition of mineral matrix by SaOS-2 as well as the activity of alkaline phosphatase, a marker of osteoblast differentiation. We then evaluated the differentiation of normal human osteoblasts by measuring alkaline phosphatase activity and again found a marked inhibition by high concentrations of magnesium. Nitric oxide, which is known to play a role in bone formation, does not seem to be involved. We hypothesize that high levels of magnesium might alter the intracellular concentration of various cations – among which calcium – by competing for the same transporters. We conclude that high magnesium levels impair osteoblast activity and might therefore contribute to bone disease.
98 citations
TL;DR: In this article, the effectiveness of different biomarkers of magnesium status was assessed through a systematic review of published magnesium supplementation and depletion trials in healthy humans, using a structured search on Ovid MEDLINE, EMBASE (Ovid) and Cochrane databases up to September 2008, followed by the use of formal inclusion/exclusion criteria, data extraction, validity assessment, and meta-analysis.
Abstract: To understand humans' requirements for magnesium and the effect of magnesium on health, it is important to identify sensitive and population-specific biomarkers of magnesium status. Thus, we assessed the effectiveness of different magnesium status biomarkers through a systematic review of published magnesium supplementation and depletion trials in healthy humans. The methods used in this study included a structured search on Ovid MEDLINE, EMBASE (Ovid) and Cochrane databases up to September 2008, followed by the use of formal inclusion/exclusion criteria, data extraction, validity assessment, and meta-analysis. A total of 20 potential biomarkers of magnesium status were assessed from 21 included publications. The majority of studies included were magnesium supplementation studies. Fewer magnesium depletion studies were identified. Available data analysis suggests that serum/plasma magnesium concentration, red blood cell (RBC) concentration and urinary magnesium excretion responded to dietary manipulation. For other biomarkers with available data, it was not possible to draw any conclusions about their usefulness as magnesium status biomarkers. The lack of data prevented detailed subgroup analysis. In conclusion, although limited data were available, serum/plasma magnesium concentration, RBC magnesium concentration and urinary magnesium excretion appear to be useful biomarkers of magnesium status in the general population. Further high-quality studies are needed to assess the effectiveness of existing and newly developed biomarkers, especially in populations that are vulnerable to magnesium deficiency.
84 citations
TL;DR: The results show the presence of subclinical alterations in Mg-ion in patients with mild to moderate AD, while no significant correlations were found in this group of patients between magnesium and ADL or IADL.
Abstract: Magnesium deficiency is present in several chronic, age-related diseases, including cardiovascular, metabolic and neurodegenerative diseases. Alzheimer's disease (AD) is the most common cause of dementia. The aim of the present study was to study magnesium homeostasis in patients with mild to moderate AD. One hundred and one elderly (≥65 years) patients were consecutively recruited (mean age: 73.4±0.8 years; M/F: 42/59). In all patients, a comprehensive geriatric assessment was performed including cognitive and functional status. Admission criteria for the AD group (diagnosed according to the DSM-IV and the NINCDS-ADRDA criteria) included: mild to moderate cognitive impairment (MMSE score: 11-24/30, corrected for age and education). Blood samples were analyzed for serum total magnesium (Mg-tot) and serum ionized magnesium (Mg-ion). AD patients had significantly lower MMSE scores (20.5±0.7 vs 27.9±0.2; p<0.001), and for the physical function tests. Mg-ion was significantly lower in the AD group as compared to age-matched control adults without AD (0.50±0.01 mmol/L vs 0.53±0.01 mmol/L; p<0.01). No significant differences were found in Mg-tot between the two groups (1.91±0.03 mEq/L vs 1.95±0.03 mEq/L; p=NS). For all subjects, Mg-ion levels were significantly and directly related only to cognitive function (Mg-ion/MMSE r=0.24 p<0.05), while no significant correlations were found in this group of patients between magnesium and ADL or IADL. Our results show the presence of subclinical alterations in Mg-ion in patients with mild to moderate AD.
70 citations
TL;DR: The evidence derived from epidemiological studies and clinical trials about the relationship between magnesium and type 2 diabetes is searched in the electronic databases of Medline, Embase, and the Cochrane Controlled Trials Register up to June 2011.
Abstract: A growing body of evidence from experimental studies that shows the essential role that magnesium exerts on glucose metabolism has been developed in last years, strongly suggesting that magnesium could plays an important roles in the reduction of the risk of developing type 2 diabetes. In the clinical setting, large epidemiological studies show that low dietary magnesium intake is associated with the increased risk of developing type 2 diabetes; however, results from randomized controlled clinical trials that have evaluated the beneficial effects of magnesium supplementation on glucose metabolism and insulin sensitivity are controversial. In this article we searched (in the electronic databases of Medline, Embase, and the Cochrane Controlled Trials Register up to June 2011) the evidence derived from epidemiological studies and clinical trials, about the relationship between magnesium and type 2 diabetes. The body of evidence from epidemiological studies consistently shows a strong inverse relationship between dietary magnesium intake and the risk of developing T2D; however, results from clinical trials are scarce and controversial.
58 citations
TL;DR: This study provides a second messenger role for Mg(2+) to explain its synergism with calcium in T cell signaling, and identifies a potential extracellular therapeutic target for T cell-specific immunomodulation.
Abstract: Although Mg(2+) has a well-recognized role as an essential cofactor for all ATP-binding enzymes, its role as a signaling ion, like Ca(2+), has been controversial. A requirement for Mg(2+)for optimal T lymphocyte stimulation was demonstrated more than 30 years ago, but the mechanism of its synergistic effect with Ca(2+)in T cell activation remains elusive. Here, we summarize our recent discovery of a signaling role for Mg(2+)in the T cell antigen receptor (TCR) signaling pathway from the study of a novel primary immunodeficiency, now named X-linked immunodeficiency with Mg(2+)defect, EBV infection and neoplasia (XMEN). XMEN patients were found to have a deficiency in magnesium transporter 1 (MAGT1), an Mg(2+)-specific transporter, which leads to the absence of a TCR-stimulated Mg(2+)flux and an attenuation of T cell activation. We further showed that this Mg(2+)flux is required proximally for the temporal orchestration of phospholipase C-γ1 (PLCγ1) activation. Thus, our study not only provides a second messenger role for Mg(2+)to explain its synergism with calcium in T cell signaling, it also identifies a potential extracellular therapeutic target for T cell-specific immunomodulation.
49 citations
TL;DR: Regression analysis indicated that magnesium was directly associated with maximal isometric trunk flexion, rotation, and handgrip, with jumping performance tests, and with all isokinetic strength variables, independent of total energy intake.
Abstract: Magnesium plays significant roles in promoting strength. Surveys of athletes reveal that intake of magnesium is often below recommended levels. We aimed to understand the impact of magnesium intake on strength in elite male basketball, handball, and volleyball players. Energy and nutrient intake were assessed from seven-day diet record. Strength tests included maximal isometric trunk flexion, extension, and rotation, handgrip, squat and countermovement Abalakov jump, and maximal isokinetic knee extension and flexion peak torques. Linear regression models were performed with significance at p<0.1. Mean magnesium intake was significantly lower than the recommended daily allowance. Regression analysis indicated that magnesium was directly associated with maximal isometric trunk flexion, rotation, and handgrip, with jumping performance tests, and with all isokinetic strength variables, independent of total energy intake. The observed associations between magnesium intake and muscle strength performance may result from the important role of magnesium in energetic metabolism, transmembrane transport and muscle contraction and relaxation.
49 citations
TL;DR: Results of this study show that, in subjects with MetS, severe hypomagnesemia, but notHypomagneemia, is associated with elevated concentrations of CRP and TNF-α, and that normomgnesemia exhibited a protective role.
Abstract: To evaluate the association between severe hypomagnesemia and the low-grade inflammatory response in subjects with metabolic syndrome (MetS), ninety-eight individuals with new diagnosis of MetS were enrolled in a cross-sectional study. Pregnancy, smoking, alcohol intake, renal damage, hepatic disorders, infectious or chronic inflammatory diseases, malignancy, use of diuretics, statins, calcium antagonist, antioxidants, vitamins, anti-inflammatory drugs, or previous oral magnesium supplementation were exclusion criteria. According serum magnesium levels, participants were assigned to the following groups: 1) severe hypomagnesemia (≤1.2 mg/dL); 2) hypomagnesemia (>1.2≤1.8 mg/dL); 3) Normal serum magnesium levels (>1.8 mg/dL). The low-grade inflammatory response was defined by elevation of serum levels of (hsCRP >1.0 ≤10.0 mg/L) or TNF-alpha (TNF-α ≥3.5 pg/mL). Severe hypomagnesemia, hypomagnesemia, and normomagnesemia were identified in 21 (21.4%), 38 (38.8%), and 39 (39.8%) individuals. The ORs, adjusted by WC, showed that severe hypomagnesemia (OR: 8.1; CI 95%: 3.6-19.4 and OR: 3.7; CI 95%: 1.1-12.1), but not hypomagnesemia (OR: 1.8; CI 95%: 0.9-15.5 and OR: 1.6; CI 95%: 0.7-3.6), was strongly associated with elevated hsCRP and TNF-α levels, and that normomagnesemia exhibited a protective role (OR: 0.32; CI 95%: 0.1-0.7 and OR: 0.28; CI 95%: 0.1-0.6) for elevation of CRP and TNF-α. Results of this study show that, in subjects with MetS, severe hypomagnesemia, but not hypomagnesemia, is associated with elevated concentrations of CRP and TNF-α.
47 citations
TL;DR: This clinical trial displays a large placebo response and could not demonstrate any significant difference in pain alleviation after a month of oral treatment between Mg and placebo in patients suffering from neuropathic pain.
Abstract: Studies in animals and in patients have suggested that magnesium (Mg), a physiological blocker of N-methyl-D-aspartate receptor, could have an antinociceptive effect in painful situations. This randomised, double-blind, controlled trial in two parallel groups aims at studying oral Mg effects in patients with neuropathic pain. It explores the impact of Mg (6x419 mg Mg chloride/capsule per day for a month), versus placebo (lactose) on pain [Neuropathic Pain Symptom Inventory (NPSI) and numerical scale (NS)], and on quality of life indicators after 4 weeks treatment, in 45 patients suffering from neuropathic pain. After 4 weeks, NPSI, NS and quality of life are not different in the Mg and placebo groups, while the frequency of pain paroxysms diminishes and the emotional component improves in the Mg group compared to baseline. This clinical trial displays a large placebo response and could not demonstrate any significant difference in pain alleviation after a month of oral treatment between Mg and placebo in patients suffering from neuropathic pain. Frequency of pain paroxysms and emotional impact will be explored in future studies as they constitute major aspects of pain alleviation in chronic pain conditions.
41 citations
TL;DR: Improved neurological function recovery and enhanced nerve regeneration were found in mice with a sciatic nerve injury that were fed a high- Mg diet, and Schwann cells may have been rescued from apoptosis by the suppression of inflammatory responses.
Abstract: Magnesium (Mg) supplements have been shown to significantly improve functional recovery in various neurological disorders. The essential benefits of Mg supplementation in peripheral nerve disorders have not been elucidated yet. The effect and mechanism of Mg supplementation on a sciatic nerve crush injury model was investigated. Sciatic nerve injury was induced in mice by crushing the left sciatic nerve. Mice were randomly divided into three groups with low-, basal- or high-Mg diets (corresponding to 10, 100 or 200% Mg of the basal diet). Neurobehavioral, electrophysiological and regeneration marker studies were conducted to explore nerve regeneration. First, a high Mg diet significantly increased plasma and nerve tissue Mg concentrations. In addition, Mg supplementation improved neurobehavioral, electrophysiological functions, enhanced regeneration marker, and reduced deposits of inflammatory cells as well as expression of inflammatory cytokines. Furthermore, reduced Schwann cell apoptosis was in line with the significant expression of bcl-2, bcl-X(L) and down-regulated expression of active caspase-3 and cytochrome C. In summary, improved neurological function recovery and enhanced nerve regeneration were found in mice with a sciatic nerve injury that were fed a high- Mg diet, and Schwann cells may have been rescued from apoptosis by the suppression of inflammatory responses.
38 citations
TL;DR: Interactions between magnesium and vanadium in the digestive and renal systems are shown and treatment with vanadium to magnesium-deficient rats corrected many of the alterations that had been generated by the magnesium deficiency.
Abstract: Vanadium is an element whose role as a micronutrient and hypoglycaemic drug has yet to be fully clarified. The present study was undertaken to investigate the bioavailability and tissue distribution of vanadium and its interactions with magnesium in healthy and in magnesium-deficient rats, in order to determine its role as a micronutrient and antidiabetic agent. Four groups were used: control (456.4 mg magnesium and 0.06 mg vanadium/kg food); control treated with 1mg vanadium/day; magnesium-deficient (164.4 mg magnesium/kg food and 0.06 mg vanadium/kg food); and magnesium-deficient treated with 1 mg vanadium/day. The vanadium was supplied in the drinking water as bis(maltolato)oxovanadium (IV). The experiment had a duration of five weeks. We measured vanadium and magnesium in excreta, serum, skeletal muscle, kidney, liver, adipose tissue and femur. Fasting glucose, insulin and total antioxidant status (TAS) in serum were studied. The vanadium treatment applied to the control rats reduced the absorption, retention, serum level and femur content of magnesium. Magnesium deficiency increased the retention and serum level of vanadium, the content of vanadium in the kidney, liver and femur (organs where magnesium had been depleted), serum glycaemia and insulin, and reduced TAS. V treatment given to magnesium-deficient rats corrected magnesium content in muscle, kidney and liver and levels of serum glucose, insulin and TAS. In conclusion, our results show interactions between magnesium and vanadium in the digestive and renal systems. Treatment with vanadium to magnesium-deficient rats corrected many of the alterations that had been generated by the magnesium deficiency.
TL;DR: The very interesting paper of Pickering et al. raises the issue of the involvement of this cation in different types of pain.
Abstract: mrh20110296 Auteur(s) : Mihai Nechifor mnechif@yahoocom Department of pharmacology, Gr T Popa University of Medicine and Pharmacy, Iasi, Romania Correspondence Mihai Nechifor, Department of Pharmacology, Gr T Popa University of Medicine and Pharmacy, Universitatii 16, Iasi 700115 Romania, Tel 0040-232-220875, 0040-744-50-8642 The very interesting paper of Pickering et al [1] raises the issue of the involvement of this cation in different types of pain Pain is very []
TL;DR: These intriguing results regarding MagT1 and its possible involvement in cellular functions reaching far beyond magnesium homeostasis are reviewed and their potential implications for magnesium research, and ultimately for therapeutic opportunities are discussed.
Abstract: Over recent years, the study of magnesium homeostasis has greatly benefited from molecular genetic approaches that identified several new classes of magnesium transporters. These proteins demonstrate a diversity of structural properties and biophysical functions that often translate into a wide range of tissue-specific cellular activities. Among these novel channels, MagT1 has gained most of the attention, given its high selectivity for Mg(2+) and its possible involvement in cellular functions reaching far beyond magnesium homeostasis, as the latest findings seem to imply. Indeed, a signaling role for MagT1 has been proven in T lymphocytes, where Mg(2+) functions as a second messenger, coupling TCR activation to intracellular effectors. We herein review these intriguing results and discuss their potential implications for magnesium research, and ultimately for therapeutic opportunities. As our knowledge of magnesium advances, it becomes increasingly clear that a deeper understanding of magnesium homeostasis is the key for a deeper insight into relevant pathophysiological conditions, and their treatment.
TL;DR: Comment on Dr Gunther's letter on “Magnesium in bone and the magnesium load test”, which appropriately raises the question of whether the concept of chronic latent magnesium deficiency (CLMD) should be re-evaluated.
Abstract: mrh.2011.0298 Auteur(s) : Ronald J Elin Department of Pathology and Laboratory Medicine, University of Louisville School of Medicine, Louisville, KY 40292, USA Correspondence. Dr. Ronald J. Elin, 627 S. Preston St. #210, Louisville, KY 40202 I appreciate the opportunity to comment on Dr Gunther's letter on “Magnesium in bone and the magnesium load test” [1]. He appropriately raises the question of whether the concept of chronic latent magnesium deficiency (CLMD) should be re-evaluated. [...]
TL;DR: This work has found that 1-5% of bone Mg is exchangeable with injected 28Mg, and the exchangeable Mg fraction could occupy a site at [...]
Abstract: mrh.2011.0297 Auteur(s) : Theodor Gunther Charite, Universitlsquatsmedizin Berlin, Campus Benjamin Franklin, Institut fur Molekularbiologie und Biochemie, Berlin, Germany Correspondence. Prof. T. Gunther, Waldhuterpfad 63, D 14169 Berlin, Germany About 50% to 70% of body magnesium (Mg) is localized in bone [1, 2]. About 30% of bone Mg is exchangeable [2]. Other authors found that 1-5% of bone Mg is exchangeable with injected 28Mg [3]. The exchangeable Mg fraction could occupy a site at [...]
TL;DR: Acute exercise at a range of submaximal intensities in euhydrated well-trained endurance athletes does not affect plasma Mg concentration, suggesting that the plasma volume plays an important role in Mg homeostasis during exercise.
Abstract: The purpose of this study was to assess the effect of exercise intensity during an incremental exercise test on plasma Mg concentration in well-trained euhydrated athletes. Twenty-seven well-trained endurance athletes carried out a cycloergometer test: after a warm-up of 10 min at 2.0 W·kg(-1), the workload increased by 0.5 W·kg(-1) every 10 min until exhaustion. Oxygen uptake (VO(2)), blood lactate concentration ([La(-)](b)), catecholamines, and plasma Mg were measured at rest, at the end of each stage and at 3, 5 and 7 minutes post-exercise. Urine specific gravity (U(SG)) was analyzed before and after the test, and subjects drank water ad libitum. Fat oxidation rate (FAT(oxr)), carbohydrate oxidation rate (CHO(oxr)), energy expenditure from fat (EE(FAT)), energy expenditure from carbohydrate (EE(CHO)), and total EE (EE(TOTAL)) were estimated using stoichiometric equations. Plasma Mg concentration at each relative exercise intensity (W·kg(-1)) were compared by means of repeated-measures ANOVA. Pearson's correlations were performed to assess the relationship between variables. The significance level was set at p<0.05. No significant differences were found in U(SG) between before and after the test (1.014±0.004 vs 1.014±0.004 g·cm(-3)). Nor were significant differences found in plasma Mg as a function of the different exercise intensities. Further, no significant correlations were detected between Mg and metabolic variables. In conclusion, acute exercise at a range of submaximal intensities in euhydrated well-trained endurance athletes does not affect plasma Mg concentration, suggesting that the plasma volume plays an important role in Mg homeostasis during exercise.
TL;DR: Oral magnesium supplementation improves vascular function in elderly diabetic patients and the authors conclude that an oral magnesium therapy [...]
Abstract: mrh.2011.0273 Auteur(s) : Klaus Kisters kisters@annahospital.de Medical Clinic I and ESH Excellence Centre, St. Anna Hospital, Herne, Germany Correspondence. K. Kisters, Medical Clinic I and ESH Excellence Centre, St. Anna Hospital, Hospitalstr. 19, 44649 Herne, Germany Dear Sir, We read with interest the recent paper of Barbagallo et al. entitled “Oral magnesium supplementation improves vascular function in elderly diabetic patients” [1]. The authors conclude that an oral magnesium therapy [...]
TL;DR: The identification of new magnesiotropic genes and related proteins will further clarify the role of the kidney in Mg(2+) homeostasis, and will potentially lead to new therapeutic approaches for hypomagnesemia.
Abstract: In healthy individuals, Mg(2+) homeostasis is tightly regulated by the concerted action of intestinal absorption, exchange with bone, and renal excretion. The kidney, more precisely the distal convoluted tubule (DCT), is the final determinant of plasma Mg(2+) concentrations. Positional cloning strategies in families with hereditary hypomagnesemia identified defects in several proteins localized in the DCT as causative factors. So far, the identified actors involved in Mg(2+) handling in the DCT include: the transient receptor potential channel melastatin member 6, the pro-epidermal growth factor, the thiazide-sensitive Na(+)-Cl(-) cotransporter, the γ-subunit of the Na(+)/K(+)-ATPase, the hepatocyte nuclear factor 1B, the potassium channels Kv1.1 and Kir4.1, and the cyclin M2. In the years to come, the identification of new magnesiotropic genes and related proteins will further clarify the role of the kidney in Mg(2+) homeostasis, and will potentially lead to new therapeutic approaches for hypomagnesemia.
TL;DR: Cognitive and psychosocial outcome in FH may influence morbidity, quality of life and social performance, and neuropsychiatric evaluation should be a routine part of management of children with FH.
Abstract: Familial hypomagnesaemia (FH) is a rare genetic condition. Neuromuscular and cardiovascular manifestations are well described, whereas cognitive and psychosocial development of children with FH is generally overlooked. Nine patients with FH were evaluated with psychiatric examination and psychometric tests for cognitive and psychosocial outcome. Nine children (median age 10.1 yrs, range 3-16.3 yrs, 5 boys and 4 girls) with FH participated. Psychiatric symptoms were hyperactivity, irritability, sleep and speech problems and finger sucking. Common psychiatric diagnoses were Attention Deficit Hyperactivity Disorder, borderline intelligence, mild mental retardation and speech disorders. Parent-rated Child Behavior Checklist and Child Health Questionnaire mean scores were between 0.32-0.79, and 0.4-2.12, respectively; indicating the worsened psychosocial well-being besides considerable psychiatric diagnoses. Cognitive and psychosocial outcome in FH may influence morbidity, quality of life and social performance. Neuropsychiatric evaluation should be a routine part of management of children with FH.
TL;DR: The aim of this study was to assess how serum Mg and Zn levels in postmenopausal women correlate with climacteric symptoms, body mass index (BMI), and the time interval since the final menstruation.
Abstract: Approximately 30% of a woman's life is spent in the postmenopausal period. This is when steroid hormone deficiency is often accompanied by mineral homeostasis perturbations and deficiencies that could be related to the intensity of any clinical symptoms. The aim of this study was to assess how serum Mg and Zn levels in postmenopausal women correlate with climacteric symptoms, body mass index (BMI), and the time interval since the final menstruation. The study involved 171 healthy, postmenopausal women, who had had their final menstruation at least one year prior to the study and who did not use menopausal hormone therapy. Both hypomagnesaemia and hypozincaemia were detected in the postmenopausal women involved in this study. The analysis revealed statistically significant differences between serum Mg levels, depending on the time interval since the final menstruation (p 0.05). In conclusion, serum Mg and Zn concentrations in postmenopausal women, not using MHT, were low. The average serum Mg levels decreased considerably with the time since the final menstruation. No correlation between BMI and worsening of climacteric symptoms and serum Mg and Zn concentrations in postmenopausal women, not using MHT was found.
TL;DR: Immunohistochemical and western blot analyses confirmed that rat mammary tissues express TRPM6 protein levels similar to those found in the kidney, and that protein expression is modulated by dietary Mg(2+).
Abstract: The epithelial Mg 2+ channel TRPM6 is considered a pivotal component in active Mg 2+ absorption and re-absorption in the intestine and kidney, but its expression and function in other tissues are largely unknown. We have previously demonstrated that extracellular Mg 2+ availability modulates TRPM6, but not the ubiquitous TRPM7, in cultured mammary epithelial cells; in addition, TRPM6 protein expression correlated to Mg 2+ influx capacities. Our results closely remind the modulation of TRPM6 described by others in murine kidney and colon following Mg 2+ dietary restriction. We sought to validate our observations by investigating whether TRPM6 modulation by extracellular Mg 2+ also occurs in vivo. To this aim, we exploited a model consisting of rats fed either with a Mg 2+-deficient or a Mg 2+-enriched diet, and studied TRPM6 expression in breast and kidney tissues. Immunohistochemical and western blot analyses confirmed that rat mammary tissues express TRPM6 protein levels similar to those found in the kidney, and that protein expression is modulated by dietary Mg 2+. In particular, Mg 2+ restriction upregulated TRPM6 expression, while Mg 2+ supplementation resulted in a significant decrease in protein levels. This work confirms and extends our previous results on TRPM6 modulation by Mg 2+ availability in mammary tissues. Further studies are required to clarify the functional significance of these findings, and the role of TRPM6 in tissue-specific magnesium homeostasis.
TL;DR: It is concluded that perioperative MgSO(4) infusion may be used as an adjunct as it decreases MAC of desflurane and suppresses the hemodynamic response to intubation.
Abstract: In this study we aimed to analyze the effect of perioperative magnesium sulphate (MgSO 4) on minimal alveolar concentration (MAC) of desflurane using bispectral index (BIS) monitoring. Sixty patients undergoing abdominal surgery under general anesthesia were randomized into two groups: Mg – receiving perioperative MgSO 4 supplementation and C – control. Anesthesia was titrated to maintain the BIS value between 45-55. MAC values, tachycardia and hypertension during intubation was found to be lower in group Mg compared to group C (p We concluded that perioperative MgSO 4 infusion may be used as an adjunct as it decreases MAC of desflurane and suppresses the hemodynamic response to intubation.
TL;DR: Higher magnesium content in the dentin of human worn teeth may constitute a defence reaction to dentin exposure, and is found in worn teeth at the 5% level.
Abstract: Aim. To compare the mineral content of the dentin of worn versus unworn teeth. Material and methods. Coronal dentin samples were collected from twenty one premolar teeth extracted for prosthetic or periodontal indications, including 11 intact teeth and 10 teeth with a significant occlusal wear. Samples were placed in concentrated nitric acid and diluted 500 times for the analysis of calcium and magnesium content and 11 times for the analysis of zinc. Contents of calcium, magnesium and zinc ions were established by means of atomic absorption spectrometry in an oxygen acetylene flame. The content of phosphorus was established by means of spectrophotometry using a test basing on a reaction of colour phosphoric-molybdenic complex formation. Data normality was assessed with Shapiro-Wilk test. Student's t-test was used for all comparisons. Results. A statistically significantly higher content of magnesium and a lower Ca/Mg ratio were found in worn teeth at the 5% level. The concentrations of the other minerals analysed were not significantly different between the worn and intact teeth at the 5% level. Conclusion. Higher magnesium content in the dentin of human worn teeth may constitute a defence reaction to dentin exposure.
TL;DR: It is found that various generations with chronic hypomagnesemia developed hypertension and dyslipidemia but not obesity, insulin resistance and diabetes mellitus type 2, and these results [...]
Abstract: mrh.2011.0275 Auteur(s) : Theodor Gunther Charite – Universitlsquatsmedizin Berlin, Campus Benjamin Franklin, Institut fur Molekularbiologie und Biochemie, Berlin, Germany Correspondence. Prof. Dr. T. Gunther, Waldhuterpfad 63, D 14169 Berlin, Germany In a preceding letter to the editor, I reported that various generations with chronic hypomagnesemia developed hypertension and dyslipidemia but not obesity, insulin resistance and diabetes mellitus type 2 [1]. These results [...]
TL;DR: The effects of MgSO(4) infusions should be considered where the aim is to achieve high doses of blood Mg(2+) levels by clinical intervention.
Abstract: Infusion of Mg for therapeutic purposes is still a matter for debate. Dosages vary considerably, yet subclinical effects on normal physiology are largely ignored. In human and animal models, interactions between Mg and insulin exist, thus we have investigated the effect of infusing Mg on serum insulin, ionised Mg (Mg 2+) and Ca (Ca 2+) and plasma glucose in human volunteers. Six male volunteers were infused with magnesium sulphate (MgSO 4) dissolved in normal saline, using a high-dose “loading” bolus, followed by a lower-level “maintenance” period. Serum Mg 2+ rose rapidly throughout the bolus infusion, declined during the maintenance phase, but remained higher than pre-infusion levels throughout the experimental period; serum Ca 2+ rose when serum Mg 2+ was highest. Infusion of MgSO 4 had no effect on heart rate or blood pressure, but caused a rapid, pronounced drop in circulating fasting insulin (p It is possible that the effect of Mg 2+ on insulin may have been due to antagonism of Ca 2+ entry in pancreatic beta-cells, the insulin decline causing a subsequent rise in circulating glucose levels. We suggest that these effects of MgSO 4 infusions should be considered where the aim is to achieve high doses of blood Mg 2+ levels by clinical intervention.
TL;DR: The paper concludes that magnesium deficiency would not be involved in insulin resistance and would not [...]
Abstract: Auteur(s) : Yves Rayssiguier, Edmond Rock Unite de Nutrition Humaine, INRA, Theix, France The letter from Gunther [1] reminds us that magnesium deficiency leads to an increase of intracellular calcium which can contribute to hypertension and insulin resistance. Therefore the proposed “ionic hypothesis” can be considered as a potential mechanism underlying the metabolic syndrome. However, the paper concludes that magnesium deficiency would not be involved in insulin resistance and would not [...]