Contemporary view of the clinical relevance of magnesium homeostasis

Genetic drivers of age-related changes in urinary magnesium excretion

Although age-dependent alterations in urinary magnesium (Mg2+) excretion have been described, the underlying mechanism remains elusive. As heritability significantly contributes to variations in urinary Mg2+ excretion, we measured urinary Mg2+ excretion at different ages in a cohort of genetically variable Diversity Outbred (DO) mice. Compared with animals aged 6 mo, an increase in Mg2+ excretion was observed at 12 and 18 mo. Quantitative trait locus (QTL) analysis revealed an association of a locus on chromosome 10 with Mg2+ excretion at 6 mo of age, with Oit3 (encoding oncoprotein-induced transcript 3; OIT3) as our primary candidate gene. To study the possible role of OIT3 in renal Mg2+ handling, we generated and characterized Oit3 knockout (Oit3-/-) mice. Although a slightly lower serum Mg2+ concentration was present in male Oit3-/- mice, this effect was not observed in female Oit3-/- mice. In addition, urinary Mg2+ excretion and the expression of renal magnesiotropic genes were unaltered in Oit3-/- mice. For animals aged 12 and 18 mo, QTL analysis revealed an association with a locus on chromosome 19, which contains the gene encoding TRPM6, a known Mg2+ channel involved in renal Mg2+ reabsorption. Comparison with RNA sequencing (RNA-Seq) data revealed that Trpm6 mRNA expression is inversely correlated with the QTL effect, implying that TRPM6 may be involved in age-dependent changes in urinary Mg2+ excretion in mice. In conclusion, we show here that variants in Oit3 and Trpm6 are associated with urinary Mg2+ excretion at distinct periods of life, although OIT3 is unlikely to affect renal Mg2+ handling.NEW & NOTEWORTHY Aging increased urinary magnesium (Mg2+) excretion in mice. We show here that variation in Oit3, a candidate gene for the locus associated with Mg2+ excretion in young mice, is unlikely to be involved as knockout of Oit3 did not affect Mg2+ excretion. Differences in the expression of the renal Mg2+ channel TRPM6 may contribute to the variation in urinary Mg2+ excretion in older mice.

The musculoskeletal syndrome of menopause

Fifty-one percent of humans are born with ovaries. As the ovarian production of estrogen diminishes in midlife and ultimately stops, it is estimated that more than 47 million women worldwide enter the menopause transition annually. More than 70% will experience musculoskeletal symptoms and 25% will be disabled by them through the transition from perimenopause to postmenopause. This often-unrecognized collective of musculoskeletal symptoms, largely influenced by estrogen flux, includes arthralgia, loss of muscle mass, loss of bone density and progression of osteoarthritis, among others. In isolation, it can be difficult for clinicians and patients to adequately appreciate the substantial role of decreasing estrogen, anticipate the onset of related symptoms and actively treat to mitigate future detrimental processes. Thus, in this review we introduce a new term, the musculoskeletal syndrome of menopause, to describe the collective musculoskeletal signs and symptoms associated with the loss of estrogen. Given the significant effects of these processes on quality of life and the associated personal and financial costs, it is important for clinicians and the women they care for to be aware of this terminology and the constellation of musculoskeletal processes for which proper risk assessment and prophylactic management are of consequence.

Nutrition-Based Support for Osteoporosis in Postmenopausal Women: A Review of Recent Evidence

Postmenopausal osteoporosis stands as the predominant bone disorder in the developed world, posing a significant public health challenge. Nutritional factors play a crucial role in bone health and may contribute to its prevention or treatment. Calcium and vitamin D, extensively studied with robust scientific evidence, are integral components of the non-pharmacological treatment for this disorder. Nevertheless, other less-explored nutritional elements appear to influence bone metabolism. This review provides a comprehensive summary of the latest evidence concerning the relationship between various nutrients, such as phosphorus, magnesium, vitamins, phytate, and phytoestrogens; specific foods like dairy or soy, and dietary patterns such as the Mediterranean diet with bone health and osteoporosis.

Review Article on Molecular Mechanism of Regulation of Hypertension by Macro-elements (Na, K, Ca and Mg), Micro-elements/Trace Metals (Zn and Cu) and Toxic Elements (Pb and As)

Hypertension (HT) is a medical condition arising due to increase in blood pressure (BP) prevalent worldwide. The balanced dietary intakes of macro-elements and micro-elements including Na, K, Ca, Mg, Zn, and Cu have been described to maintain BP in humans by regulating the osmolarity of blood, cells/tissues, prevention of generation of oxidative and nitrosative stress (OANS), and endothelial damage through their functioning as important components of renin-angiotensin-aldosterone system (RAAS), antioxidant enzyme defense system, and maintenance of blood vascular-endothelial and vascular smooth muscle cell (VSMC) functions. However, inadequate/excess dietary intakes of Na/K, Ca/Mg, and Zn/Cu along with higher Pb and As exposures recognized to induce HT through common mechanisms including the followings: endothelial dysfunctions due to impairment of vasodilatation, increased vasoconstriction and arterial stiffness, blood clotting, inflammation, modification of sympathetic activity and higher catecholamine release, increased peripheral vascular resistance, and cardiac output; increased OANS due to reduced and elevated activities of extracellular superoxide dismutase and NAD(P)H oxidase, less nitric oxide bioavailability, decrease in cGMP and guanylate cyclase activity, increase in intracellular Ca2+ ions in VSMCs, and higher pro-inflammatory cytokines; higher parathyroid and calcitriol hormones; activation/suppression of RAAS resulting imbalance in blood Na+, K+, and water regulated by renin, angiotensin II, and aldosterone through affecting natriuresis/kaliuresis/diuresis; elevation in serum cholesterol and LDL cholesterol, decrease in HDL cholesterol due to defect in lipoprotein metabolism. The present study recommends the need to review simple dietary mineral intervention studies/supplementation trials before keeping their individual dietary excess intakes/exposures in consideration because their interactions lead to elevation and fall of their concentrations in body affecting onset of HT.

Long-term cisplatin nephrotoxicity after childhood cancer: a systematic review and meta-analysis

BACKGROUND

Cisplatin is a chemotherapeutic drug commonly used in the treatment of many childhood solid malignancies. It is known to cause long-term nephrotoxicity, most commonly manifesting as reduced glomerular filtration rate and hypomagnesaemia. Existing literature regarding the epidemiology of long-term nephrotoxicity in childhood cancer describes large variation in prevalence and risk factors.

OBJECTIVES

This study is to evaluate the prevalence of, and risk factors for, long-term cisplatin nephrotoxicity after treatment for childhood cancer.

STUDY ELIGIBILITY CRITERIA

Studies were eligible for inclusion if they: (i) evaluated participants treated with cisplatin who were diagnosed with cancer < 18 years of age; (ii) investigated any author-defined measure of nephrotoxicity; and (iii) performed this evaluation 3 or more months after cisplatin cessation. Studies whose scope was broader than this were included if appropriate subgroup analysis was performed.

RESULTS

Prevalence of reduced glomerular filtration rate (GFR) ranged between 5.9 and 48.1%. Pooled prevalence of reduced GFR using studies with a modern consensus threshold of 90 ml/min/1.73 m2 was 29% (95% CI 0.0-58%). Prevalence of hypomagnesaemia ranged between 8.0 and 71.4%. Pooled prevalence of hypomagnesaemia was 37% (95% CI 22-51%). Substantial heterogeneity was present, with I2 statistics of 94% and 73% for reduced GFR and hypomagnesaemia respectively. All large, long-term follow-up studies described increased risk of reduced GFR with increasing cumulative cisplatin dose. Included studies varied as to whether cisplatin was a risk factor for proteinuria, and whether age was a risk factor for cisplatin nephrotoxicity.

LIMITATIONS

A wide range of study methodologies were noted which impeded analysis. No studies yielded data from developing health-care settings. No non-English studies were included, further limiting generalisability.

CONCLUSIONS

Both of the most common manifestations of long-term cisplatin nephrotoxicity have a prevalence of approximately a third, with increasing cumulative dose conferring increased risk of nephrotoxicity. Further work is needed to characterise the relationship between reduced GFR and hypomagnesaemia, investigate other risk factors and understand the interindividual variation in susceptibility to nephrotoxicity.

Improving diagnosis and treatment of hypomagnesemia

Magnesium is one of the most abundant cations in the body and acts as a cofactor in more than 600 biochemical reactions. Hypomagnesemia is a highly prevalent condition, especially in subjects with comorbid conditions, but has received less attention than other electrolyte disturbances. This review will discuss magnesium physiology, absorption, storage, distribution across the body, and kidney excretion. After reviewing the regulation of magnesium homeostasis, we will focus on the etiology and clinical presentation of hypomagnesemia. The role of laboratory medicine in hypomagnesemia will be the main purpose of this review, and we will discuss the laboratory tests and different samples and methods for its measurement. Although free magnesium is physiologically active, total serum magnesium is the most commonly used measurement in laboratory medicine and is apt for clinical purposes; however, it is not appropriately used, and many patients with hypomagnesemia remain undiagnosed and not treated. Using information technologies, laboratory medicine can largely improve the diagnosis and treatment of hypomagnesemia through the design and establishment of automatic demand management and result management interventions by acting in the first and last steps of the laboratory cycle, test requests, and actions taken after test results, to unmask patients with hypomagnesemia and improve the number of patients undergoing treatment.

Lanthanide-based luminescent probes for biological magnesium: accessing polyphosphate-bound Mg2

Biomolecule-bound Mg2+ species, particularly polyphosphate complexes, represent a large and dynamic fraction of the total cellular magnesium that is essential for cellular function but remains invisible to most indicators. Here we report a new family of Eu(III)-based indicators, the MagQEu family, functionalized with a 4-oxo-4H-quinolizine-3-carboxylic acid metal recognition group/sensitization antenna for turn-on, luminescence-based detection of biologically relevant Mg2+ species.

Acquired Disorders of Hypomagnesemia

Magnesium disorders are common in clinical practice and when present can manifest clinically as cardiovascular, neuromuscular, or other organ dysfunction. Hypomagnesemia is far more common than hypermagnesemia, which is largely seen in patients with reduced glomerular filtration rates receiving magnesium-containing medications. In addition to inherited disorders of magnesium handling, hypomagnesemia is also seen with excessive gastrointestinal or renal losses and due to medications such as amphotericin B, aminoglycosides, and cisplatin. Laboratory assessment of body magnesium stores largely relies on the measurement of serum magnesium levels that are a poor proxy for total body stores but does correlate with the development of symptoms. Replacement of magnesium can be challenging, with oral replacement strategies being generally more effective at slowly replacing body stores but intravenous replacement being more effective at treating the more life-threatening and severe cases of hypomagnesemia. We conducted a thorough review of the literature using PubMed (1970-2022) and the search terms magnesium, hypomagnesemia, drugs, medications, treatment, and therapy. In the absence of clear data on optimal management of hypomagnesemia, we have made recommendations on magnesium replacement based on our clinical experience.

UK Reference Intervals for Parathyroid Hormone Using Abbott Methods

Background: Diagnosis of hyperparathyroidism requires measurement of parathyroid hormone (PTH) in the context of the plasma calcium and other factors, such as vitamin D status and renal function. Accurate classification depends upon an appropriate population reference interval. We examined local population plasma PTH reference intervals at four different UK sites using a common platform. Methods: Plasma PTH results were extracted from laboratory information systems at four different UK sites, all using the Abbott Architect i2000 method. We included only people with normal adjusted serum calcium, magnesium, vitamin D, and renal function. Following outlier rejection lower and upper reference limits were derived. Results: An overall reference interval for plasma PTH of 3.0-13.7 pmol/L was observed using a non-parametric approach compared to 2.9-14.1 pmol/L using a parametric approach, notably higher than the manufacturer's representative range of 1.6-7.2 pmol/L. We also noted statistically significant differences (p < 0.00001) between some sites with upper limits ranging from 11.5 to 15.8 pmol/L which may be due to different population characteristics of each group. Conclusion: Locally derived reference intervals may be beneficial for UK populations and revised upper thresholds are necessary when using the Abbott PTH method to avoid inappropriate classification of patients as having hyperparathyroidism.

Higher magnesium levels are associated with better glycaemic control and diabetes remission post-bariatric surgery

BACKGROUND

Low Magnesium (Mg) dietary intake has been associated with increased risk of type 2 diabetes mellitus (T2DM). Furthermore, in patients with T2DM, hypomagnesemia is associated with worst glycaemic control. Bariatric surgery (BS) remains the most effective treatment in severe obesity and also provides resolution/improvement of T2DM. Our aim is to evaluate the association between Mg supplementation post-BS and Mg serum levels with diabetes status after BS.

METHODS

We performed an observational study on patients with obesity and T2DM who underwent BS. Data was assessed pre-BS and one-year post-BS.

RESULTS

We included a total of 403 patients with T2DM. At baseline, 43.4% of the patients had Mg deficiency. Pre-BS, patients with Mg deficiency had poorer glycaemic control - HbA1c 7.2 ± 1.6% vs 6.4 ± 1.0% (p < 0.001), fasting plasma glucose 146.2 ± 58.8 mg/dL vs 117.5 ± 36.6 mg/dL (p < 0.001) and were under a greater number of anti-diabetic drugs 1.0 (IQR 0-2.0) vs 1.0 (IQR 0-1.0) (p = 0.002). These findings persisted at one-year post-BS. At the first-year post-BS, 58.4% of the patients had total remission of T2DM and 4.1% had partial remission. Patients without Mg deficiency at one-year post-BS had higher rates of total and partial remission. Higher serum Mg levels at baseline is an independent predictor of total T2DM remission (p < 0.0001). The optimal cut-off of baseline Mg to predict total T2DM remission was 1.50 mg/dL with a sensitivity of 73% and a specificity of 58% (area under ROC = 0.65). Patients that were under Mg supplementation post-BS had serum Mg values, glycaemic control and total remission of T2DM similar to patients non-supplemented.

CONCLUSION

In patients with T2DM submitted to BS, higher Mg serum levels at baseline and 1-year after BS were associated with better glycaemic control and higher rates of total T2DM remission at the first year post-BS.

Association between Serum Magnesium Levels and Mortality in a Community-Based Population: The Yamagata (Takahata) Study

The element magnesium (Mg) is involved in various metabolic reactions within the human body, and its deficiency is considered a risk factor for several diseases. In this study, we investigated the relationship between serum Mg levels and mortality in a community-based population. We prospectively assessed the association between serum Mg levels at enrollment and all-cause mortality in 1,314 participants who underwent a community health examination. The mean serum Mg level was 2.4 (±0.2) mg/dL. Patients with serum Mg levels ≤2.3 mg/dL constituted the low Mg group, while those with serum Mg ≥2.4 mg/dL constituted the high Mg group. Ninety-three (7.1%) patients died during the 10-y follow-up period. Kaplan-Meier analysis revealed that all-cause mortality was significantly higher in the low Mg group (log-rank p<0.05). Cox proportional hazards analysis revealed a significant association in the unadjusted model (hazard ratio [HR] 1.72, 95% confidence intervals [CI] 1.14-2.58, p<0.01) and in the fully adjusted model (HR 1.73, 95% CI 1.09-2.76, p<0.05). This association was particularly strong in males (HR 2.08, 95% CI 1.19-3.63, p<0.05). Low serum Mg levels were significantly associated with the risk of all-cause mortality among males in a community-based Japanese population.

Does Ionized Magnesium Offer a Different Perspective Exploring the Association between Magnesemia and Targeted Cardiovascular Risk Factors?

Evidence of the association of magnesium (Mg) with arterial stiffness has so far been conflicting. The interplay between hypertension and elevated body mass index (BMI), with hypomagnesemia, instead, has been described in the literature in a more consistent way. Our study aims at revisiting the correlations between blood Mg levels and hemodynamic and body composition parameters in the general population, exploring the sensitivity profile of ionized Mg (Ion-Mg) compared to total Mg (Tot-Mg). We collected data from 755 subjects randomly chosen from a Swiss population previously described and stratified our sample into four equivalent classes according to ionized (whole blood) and total (serum) magnesium. After correcting for age, statistically significant differences emerged between: (i) Tot-Mg ≤ 0.70 and 0.81 ≤ Tot-Mg ≤ 0.90 for cf-PWV (p = 0.039); (ii) Tot-Mg ≤ 0.70 and Tot-Mg ≥ 0.91 for o-PWV (p = 0.046). We also found a statistically significant difference among groups of Ion-Mg values for the 24 h extremes of systolic blood pressure (p = 0.048) and among groups of Tot-Mg for BMI (p = 0.050). Females showed significantly lower levels of total magnesium (p = 0.035) and ionized magnesium (p < 0.001) than males. The overall agreement between magnesium analysis methods was 64% (95%CI: 60.8−67.7%). Our results confirm that Ion-Mg compared with Tot-Mg offers a different profile in detecting both correlations with hemodynamic and body composition parameters and dysmagnesemias. Lower levels of magnesium were associated with worse arterial aging parameters, larger 24 h blood pressure excursions, and higher BMI. Ion-Mg was superior in detecting the correlation with blood pressure only. Considering Ion-Mg as a more specific marker of the magnesium status, and the partially contradictory results of our explorative cross-sectional study, to avoid confounding factors and misinterpretations, ionized magnesium should be used as reference in future studies.

Magnesium Status and Calcium/Magnesium Ratios in a Series of Cystic Fibrosis Patients

Magnesium (Mg) is an essential micronutrient that participates in various enzymatic reactions that regulate vital biological functions. The main aim was to assess the Mg status and its association with nutritional indicators in seventeen cystic fibrosis (CF) patients. The serum Mg and calcium (Ca) levels were determined using standardized methods and the dietary Mg intake by prospective 72 h dietary surveys. The mean serum Ca (2.45 mmol/L) and Mg (0.82 mmol/L) had normal levels, and the mean dietary intake of the Ca (127% DRI: Dietary Reference Intake) and Mg (125% DRI) were high. No patients had an abnormal serum Ca. A total of 47% of the subjects had hypomagnesemia and 12% insufficient Mg consumption. One patient had a serum Mg deficiency and inadequate Mg intake. A total of 47 and 82% of our series had a high serum Ca/Mg ratio of >4.70 (mean 4.89) and a low Ca/Mg intake ratio of <1.70 (mean 1.10), respectively. The likelihood of a high Ca/Mg ratio was 49 times higher in patients with a serum Mg deficiency than in normal serum Mg patients. Both Ca/Mg ratios were associated with the risk of developing cardiovascular disease (CVD), type 2 diabetes (T2D), metabolic syndrome (MetS), and even several cancers. Therefore, 53% of the CF patients were at high risk of a Mg deficiency and developing other chronic diseases.

Fibroblast growth factor 23 is independently associated with renal magnesium handling in patients with chronic kidney disease

BACKGROUND

Disturbances in magnesium homeostasis are common in patients with chronic kidney disease (CKD) and are associated with increased mortality. The kidney is a key organ in maintaining normal serum magnesium concentrations. To this end, fractional excretion of magnesium (FEMg) increases as renal function declines. Despite recent progress, the hormonal regulation of renal magnesium handling is incompletely understood. Fibroblast Growth Factor 23 (FGF23) is a phosphaturic hormone that has been linked to renal magnesium handling. However, it has not yet been reported whether FGF23 is associated with renal magnesium handling in CKD patients.

METHODS

The associations between plasma FGF23 levels, plasma and urine magnesium concentrations and FEMg was investigated in a cross-sectional cohort of 198 non-dialysis CKD patients undergoing renal biopsy.

RESULTS

FGF23 was significantly correlated with FEMg (Pearson's correlation coefficient = 0.37, p<0.001) and urinary magnesium (-0.14, p=0.04), but not with plasma magnesium. The association between FGF23 and FEMg remained significant after adjusting for potential confounders, including estimated glomerular filtration rate (eGFR), parathyroid hormone and 25-hydroxyvitamin D.

CONCLUSIONS

We report that plasma FGF23 is independently associated with measures of renal magnesium handling in a cohort of non-dialysis CKD patients. A potential causal relationship should be investigated in future studies.

Preparation of Mg/PCL electrospun membranes and preliminary study

Magnesium (Mg) metal and its alloy degradation product magnesium ion (Mg2+) can stimulate the metabolic activity of bone cells, which is beneficial to bone growth and healing. With biodegradable polycaprolactone (PCL) and magnesium particles as raw materials, electrospinning technology is used to prepare electrospun membrane materials doped with magnesium particles. Meanwhile, the scanning electron microscope, X-ray diffraction analysis technology and microcomputer-controlled electronic universal testing machine are adopted to analyze the physical and chemical properties of the material. The biocompatibility of electrospun membranes and their potential to induce osteogenic differentiation of human dental pulp stem cells (hDPSCs) were evaluated by in vitro cell experiments. The results showed that magnesium/PCL electrospun membranes doped with magnesium particles were successfully prepared with electrospinning technology, and the material has a good porous structure. Magnesium/PCL electrospun membranes have good biocompatibility and have the potential to induce osteogenic differentiation of hDPSCs. Among them, the effects of 10% magnesium/PCL electrospun membranes were the most obvious. Clinically, these materials provide new ideas for the restoration of alveolar bone defects and provide an experimental basis for the realization of alveolar bone regeneration.

Nutritional, physicochemical and sensorial acceptance of functional cookies enriched with xiquexique (Pilosocereus gounellei) flour

The objective of this study was the production of innovative functional cookies enriched with two different sizes (100 and 28 mesh) xiquexique flour by substitution ratio 50% of wheat flour and monitoring the impact of these enrichments on the nutritional, physicochemical, texture characteristics and consumer acceptance. The physicochemical characteristics and sensorial properties of the xiquexique cookies were evaluated in a pursuit to identify an innovative bakery ingredient with high nutritional value and potential function that could be exploited by the food industry. The water activity and moisture values were low, which can provide greater stability during storage of food matrices, such as cookies. The xiquexique cookies had greater ash (2.47-2.74%), protein (0.94-1.36%), fiber (4.41-8.10%), and resistant starch (3.65-2.10%) contents than their respective controls with 100% wheat flour. The functional cookies were rich in minerals: mainly calcium, iron, potassium, magnesium and manganese and can be consumed by all individuals to help meet daily needs, especially those of people who have increased needs for these essential nutrients. In addition to the darker color of the xiquexique cookies, the hardness of these was higher than that of the control cookies, while the expansion index was smaller. The data from the Check All That Apply sensory method, which consists of a test used mainly for recipe adjustments and the development of ideal food products, confirmed that xiquexique flour have the potential for the development of bakery products such as cookies.

Circulating Serum Magnesium and the Risk of Venous Thromboembolism in Men: A Long-Term Prospective Cohort Study

Background and Objective

Serum magnesium, an essential trace element involved in processes that regulate cardiovascular function, has been linked to the risk of atherosclerotic cardiovascular disease. However, the potential association between serum magnesium and venous thromboembolism (VTE) has not been previously investigated. We aimed to assess the prospective association of serum magnesium with the risk of VTE.

Methods

Serum magnesium was measured using atomic absorption spectrometry in 2,361 men aged 42-61 years with no history of VTE at baseline in the Kuopio Ischemic Heart Disease prospective cohort. Cox regression models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for VTE.

Results

A total of 159 incident VTE events were recorded during a median follow-up of 27.1 years. The risk of VTE per 1 SD increase in serum magnesium in the age-adjusted analysis was (HR 1.30; 95% CI 0.46-3.69). The association remained consistent in analyses adjusted for systolic blood pressure, body mass index, total cholesterol, triglycerides, smoking status, a history of type 2 diabetes, a history of coronary heart disease, medication for dyslipidemia, alcohol consumption, physical activity, socioeconomic status, serum active calcium, high-sensitivity C-reactive protein, and a history of cancer (HR 1.38; 95% CI 0.48-3.96). Comparing the extreme tertiles of serum magnesium, the corresponding adjusted HRs were 1.17 (95% CI 0.81-1.70) and 1.17 (95% CI 0.81-1.70), respectively.

Conclusion

In a middle-aged Caucasian male population, serum-circulating magnesium was not associated with a future risk of VTE. Further studies in women, other age groups, and other populations are required to generalize these findings.

Prognostic value of admission serum magnesium in acute myocardial infarction complicated by malignant ventricular arrhythmias

OBJECTIVES

Although electrolyte abnormalities are related to worse clinical outcomes in patients with acute myocardial infarction (AMI), little is known about the association between admission serum magnesium level and adverse events in AMI patients complicated by out-of-hospital cardiac arrest presenting with malignant ventricular arrhythmias (OHCA-MVA). We investigated the prognostic value of serum magnesium level on admission in these patients.

METHODS

We retrospectively analyzed the data of 165 consecutive reperfused AMI patients complicated with OHCA-MVA between April 2007 and February 2020 in our university hospital. Serum magnesium concentration was measured on admission. The primary outcome was in-hospital death.

RESULTS

Fifty-four patients (33%) died during hospitalization. Higher serum magnesium level was significantly related to in-hospital death (Fine & Gray's test; p < 0.001). In multivariable logistic regression analyses, serum magnesium level on admission was independently associated with in-hospital death (hazard ratio 2.68, 95% confidence interval 1.24-5.80) even after adjustment for covariates. Furthermore, the incidences of cardiogenic shock necessitating an intra-aortic balloon pump (p = 0.005) or extracorporeal membrane oxygenation (p < 0.001), tracheal intubation (p < 0.001) and persistent vegetative state (p = 0.002) were significantly higher in patients with higher serum magnesium level than in those with lower serum magnesium level.

CONCLUSIONS

In reperfused AMI patients complicated by OHCA-MVA, admission serum magnesium level might be a potential surrogate marker for predicting in-hospital death.

Wernicke's encephalopathy - from basic science to clinical practice. Part 1: Understanding the role of thiamine

Wernicke's encephalopathy (WE) is an acute neuropsychiatric state. Untreated, WE can lead to coma or death, or progress to Korsakoff syndrome (KS) - a dementia characterized by irreversible loss of anterograde memory. Thiamine (vitamin B1) deficiency lies at the heart of this condition. Yet, our understanding of thiamine regarding prophylaxis and treatment of WE remains limited. This may contribute to the current undertreatment of WE in clinical practice. The overall aim of this review is to identify the best strategies for prophylaxis and treatment of WE in regard to (a) dose of thiamine, (b) mode of administration, (c) timing of switch from one mode of administration to another, (d) duration of administration, and (e) use of magnesium along thiamine as an essential cofactor. Evidence from randomized controlled trials and other intervention studies is virtually absent. Therefore, we have to resort to basic science for proof of principle instead. Here, we present the first part of our clinical review, in which we explore the physiology of thiamine and the pathophysiology of thiamine deficiency. We first explore both of these in their historical context. We then review the pharmacodynamics and pharmacokinetics of thiamine, exploring the roles of the six currently known thiamine compounds, their transporters, and target enzymes. We also explore the significance of magnesium as a cofactor in thiamine-facilitated enzymatic reactions and thiamine transport. In the second (forthcoming) part of this review, we will use the findings of the current review to make evidence-based inferences about strategies for prophylaxis and treatment of WE.

Plasma Magnesium Concentrations and Risk of Incident Cancer in Adults with Hypertension: A Nested Case-Control Study

OBJECTIVE

The association between plasma magnesium and risk of incident cancer remains inconclusive in previous studies. We aimed to investigate the prospective relationship of baseline plasma magnesium concentrations with the risk of incident cancer and to examine possible effect modifiers.

METHODS

A nested case-control study with 228 incident cancer cases and 228 matched controls was conducted using data from the China Stroke Primary Prevention Trial (CSPPT), a randomized, double-blind, controlled trial, conducted from May 2008 to August 2013. Study outcomes included incident cancer and its subtypes.

RESULTS

When plasma magnesium concentrations were assessed as quartiles, a significantly higher incident risk of total cancer was found in participants in quartile 1 (<0.76 mmol/L; odds ratio [OR] = 2.70; 95% CI: 1.33-5.49) and quartile 4 (≥0.89 mmol/L; OR = 2.05; 95% CI: 1.12-3.76), compared with those in quartile 3 (0.83 to <0.89 mmol/L). In cancer site-specific analyses, similar trends were found for gastrointestinal cancer, esophageal cancer, gastric cancer, breast cancer, lung cancer, and other cancers. Furthermore, none of the variables, including age, sex, current smoking status, current alcohol intake, BMI, systolic blood pressure, and total cholesterol levels at baseline significantly modified the association between plasma magnesium and cancer risk.

CONCLUSIONS

Both low and high plasma magnesium concentrations were significantly associated with an increased incident risk of cancer, compared with the reference concentrations of 0.83 to <0.89 mmol/L among hypertensive adults.

Magnesium Status and Stress: The Vicious Circle Concept Revisited

Magnesium deficiency and stress are both common conditions among the general population, which, over time, can increase the risk of health consequences. Numerous studies, both in pre-clinical and clinical settings, have investigated the interaction of magnesium with key mediators of the physiological stress response, and demonstrated that magnesium plays an inhibitory key role in the regulation and neurotransmission of the normal stress response. Furthermore, low magnesium status has been reported in several studies assessing nutritional aspects in subjects suffering from psychological stress or associated symptoms. This overlap in the results suggests that stress could increase magnesium loss, causing a deficiency; and in turn, magnesium deficiency could enhance the body’s susceptibility to stress, resulting in a magnesium and stress vicious circle. This review revisits the magnesium and stress vicious circle concept, first introduced in the early 1990s, in light of recent available data.

Headaches and Magnesium: Mechanisms, Bioavailability, Therapeutic Efficacy and Potential Advantage of Magnesium Pidolate

Magnesium deficiency may occur for several reasons, such as inadequate intake or increased gastrointestinal or renal loss. A large body of literature suggests a relationship between magnesium deficiency and mild and moderate tension-type headaches and migraines. A number of double-blind randomized placebo-controlled trials have shown that magnesium is efficacious in relieving headaches and have led to the recommendation of oral magnesium for headache relief in several national and international guidelines. Among several magnesium salts available to treat magnesium deficiency, magnesium pidolate may have high bioavailability and good penetration at the intracellular level. Here, we discuss the cellular and molecular effects of magnesium deficiency in the brain and the clinical evidence supporting the use of magnesium for the treatment of headaches and migraines.

The Association Between the Concentration of Serum Magnesium and Postmenopausal Osteoporosis

Background: Osteoporosis is the most common and widespread chronic skeletal metabolic disease in the world and can lead to catastrophic fractures. Therefore, it is important to look for factors that can be modified or controlled to prevent osteoporosis. Although serum Mg is believed to be associated with osteoporosis in many individuals, there are conflicting reports on the association between serum Mg and osteoporosis. Therefore, this meta-analyses aimed to explore the association between the concentration of serum Mg and osteoporosis as well as that between the concentration of serum Mg and osteopenia.

Methods: Articles were searched in PubMed. We also reviewed the reference lists of the relevant publications and reviews as of December 2019. Finally, 11 eligible studies involving 2,776 postmenopausal women were selected. We performed subgroup analysis, and publication bias was assessed.

Results: According to the forest plot analysis, postmenopausal women with osteoporosis had a lower concentration of serum Mg than normal controls [standardized mean difference (SMD) = −0.56, 95% confidence interval (CI) = −1.02 to −0.09]. However, this result was not applicable to those with osteopenia (SMD = −0.30, 95% CI = −0.69 to 0.09). The subgroup analysis by geographical location found a similar pattern in European postmenopausal women with osteoporosis (SMD = −0.73, 95% CI = −1.322 to −0.143), but not in Asian (SMD = −0.007, 95% CI = −0.381 to 0.394). The subgroup analysis by site of bone mineral density (BMD) showed the serum Mg concentration of postmenopausal women with osteoporosis (BMD of femur) was lower than in healthy controls (SMD = −0.44, 95% CI = −0.77 to −0.12), and BMD of the spine group had the same conclusion (SMD = −0.78, 95% CI = −1.36 to −0.19). Besides, the serum Mg concentration of postmenopausal women with osteoporosis was lower than that of the normal bone mass group in the studies those included more than 50 postmenopausal women with osteoporosis (SMD = −0.57, 95% CI = −1.04 to −0.11). We also found postmenopausal women under the age of 60 with osteoporosis had a lower concentration of serum Mg than the healthy controls (SMD = −0.61, 95% CI = −1.09 to −0.13).

Conclusion: Postmenopausal women with osteoporosis have a lower concentration of serum Mg. However, the association between the concentration of serum Mg and osteopenia needs further confirmation.

Response of Vitamin D after Magnesium Intervention in a Postmenopausal Population from the Province of Granada, Spain

Menopause is a stage of hormonal imbalance in women which, in addition to other physiopathological consequences, poses a risk of deficiency of key micronutrients such as magnesium and vitamin D. A study was made of the influence of a magnesium intervention upon vitamin D status in a postmenopausal population from the province of Granada (Spain). Fifty-two healthy postmenopausal women between 44–76 years of age were included. Two randomized groups—placebo and magnesium (500 mg/day)—were treated during eight weeks. Nutrient intake was assessed using questionnaires based on 72-h recall. Vitamin D was analyzed by liquid chromatography—tandem mass spectrometry. Baseline vitamin D proved deficient in over 80% of the subjects. The administration of magnesium resulted in significantly increased vitamin D levels in the intervention group versus the controls (p < 0.05). Magnesium supplementation improved vitamin D status in the studied postmenopausal women.

Variations in Magnesium Concentration Are Associated with Increased Mortality: Study in an Unselected Population of Hospitalized Patients

Dysmagnesemia is a serious disturbance of microelement homeostasis. The aim of this study was to analyze the distribution of serum magnesium concentrations in hospitalized patients according to gender, age, and result of hospitalization. The study was conducted from February 2018 to January 2019 at the Central Clinical Hospital in Warsaw. Laboratory test results from 20,438 patients were included in this retrospective analysis. When a lower reference value 0.65 mmol/L was applied, hypermagnesemia occurred in 196 patients (1%), hypomagnesemia in 1505 patients (7%), and normomagnesemia in 18,711 patients (92%). At a lower reference value of 0.75 mmol/L, hypomagnesemia was found in 25% and normomagnesemia in 74% of patients. At a lower reference value of 0.85 mmol/L, hypomagnesemia was found in 60% and normomagnesemia in 39% of patients. Either hypo- or hyper-magnesemia was associated with increased risk of in-hospital mortality. This risk is the highest in patients with hypermagnesemia (40.1% of deaths), but also increases inversely with magnesium concentration below 0.85 mmol/L. Serum magnesium concentration was not gender-dependent, and there was a slight positive correlation with age (p < 0.0001, r = 0.07). Large fluctuations in serum magnesium level were associated with increased mortality (p = 0.0017). The results indicate that dysmagnesemia is associated with severe diseases and generally severe conditions. To avoid misdiagnosis, an increase of a lower cut-off for serum magnesium concentration to at least 0.75 mmol/L is suggested.

[Expert Council Resolution. Practical Aspects of the Diagnosis and Correction of Potassium and Magnesium Deficiency States]

The article analyzes properties of potassium and magnesium, which may exert vasodilatory, anti-inflammatory, anti-ischemic, antiaggregant, and antiarrhythmic effects. These are extremely important microelements and potentially beneficial therapeutic agents for treatment of cardiovascular diseases.

The Effect of Sheep and Cow Milk Supplementation of a Low Calcium Diet on the Distribution of Macro and Trace Minerals in the Organs of Weanling Rats

The aim of this study was to investigate the effect of either sheep or cow milk supplementation to a low calcium and phosphorus diet on growth and organ mineral distribution in weanling rats. Rats were fed diets consisting of either a control chow, a 50% reduced calcium and phosphorous chow (low Ca/P), low Ca/P and sheep milk, or low Ca/P and cow milk diet for 28 days. Food intake of the rats, the growth rate of the rats, and the concentrations of minerals in the soft organs and serum were determined. Rats fed the low Ca/P diet alone had lower weight gain than rats consuming either of the milk-supplemented diets (p < 0.05). Both sheep milk and cow milk supplementation overcame the effects of consuming a diet restricted in calcium and phosphorus but the sheep milk was effective at a significantly lower level of milk intake (p < 0.05). Significant differences (p < 0.05) in essential and trace mineral concentrations due to milk type were observed in the kidney, spleen, and liver. For non-essential minerals, significant differences (p < 0.05), related to diet, were observed in all organs for arsenic, cesium, rubidium, and strontium concentrations.

Metformin regulates TRPM6, a potential explanation for magnesium imbalance in type 2 diabetes patients

Metformin therapy is associated with lower serum magnesium (Mg²⁺) levels in type 2 diabetes patients. The TRPM6 channel determines the fine-tuning of Mg²⁺ (re)absorption in intestine and kidney. Therefore, we aimed to investigate the short- and long-term effects of metformin on TRPM6. Patch clamp recordings and biotinylation assays were performed upon 1 h of incubation with metformin in TRPM6-transfected HEK293 cells. Additionally, 24 h of treatment of mDCT15 kidney and hCaco-2 colon cells with metformin was applied to measure the effects on endogenous TRPM6 expression by quantitative real-time PCR. To assess Mg²⁺ absorption, ²⁵Mg²⁺ uptake measurements were performed using inductively coupled plasma mass spectrometry. Short-term effects of metformin significantly increased TRPM6 activity and its cell surface trafficking. In contrast, long-term effects significantly decreased TRPM6 mRNA expression and ²⁵Mg²⁺ uptake. Metformin lowered TRPM6 mRNA levels independently of insulin- and AMPK-mediated pathways. Moreover, in type 2 diabetes patients, metformin therapy was associated with lower plasma Mg²⁺ concentrations and fractional excretion of Mg²⁺. Thereby, short-term metformin treatment increases TRPM6 activity explained by enhanced cell surface expression. Conversely, long-term metformin treatment results in downregulation of TRPM6 gene expression in intestine and kidney cells. This long-term effect translated in an inverse correlation between metformin and plasma Mg²⁺ concentration in type 2 diabetes patients.

Effects of Oral Magnesium Supplementation on Vascular Function: A Systematic Review and Meta-analysis of Randomized Controlled Trials

INTRODUCTION

The effects of magnesium (Mg) supplementation on vascular function have been evaluated in some randomized controlled trials (RCT) but their results are conflicting.

AIM

A systematic review and meta-analysis were conducted to summarize the effects of oral Mg supplementation on vascular function in RCT.

METHODS

The databases MEDLINE (PubMed), Embase, Web of Science and Cochrane Library were accessed from inception to May 27, 2019. Intergroup differences (treatment vs. control group) related to changes in flow-mediated dilation (FMD) and pulse wave velocity (PWV), expressed as mean and standard deviation, were used to evaluate the effect of Mg supplementation on these outcomes. The results of the meta-analysis were expressed using a random-effects model. The heterogeneity between studies was evaluated using the I² statistic.

RESULTS

The oral supplementation of Mg had no significant effect on FMD (mean difference 2.13; 95% CI - 0.56, 4.82; p = 0.12) and PWV (mean difference - 0.54, 95% CI - 1.45, 0.36, p = 0.24). Heterogeneity for both outcomes (FMD and PWV) was high (I² = 99%, p < 0.001). However, in subgroup analyses, oral Mg significantly improved FMD in studies longer than 6 months, in unhealthy subjects, in individuals older than 50 years, or in those with body mass index (BMI) ≥ 25 kg/m². The reduced number of RCT and the heterogeneity among them were the main limitations.

CONCLUSIONS

This meta-analysis suggest that oral Mg supplementation may improve endothelial function when conducted at least for 6 months and in unhealthy, overweight or older individuals. Registration number: PROSPERO CRD42019111462.

Case Report: Investigation and molecular genetic diagnosis of familial hypomagnesaemia

Genetic mutations causing familial hypomagnesaemia syndromes are well-recognised.  Affected patients can present with severe symptoms of hypomagnesaemia, such as seizures or cardiac arrhythmia.  We report an affected child, from a consanguineous family, who presented in the first weeks of life with seizures secondary to hypomagnesaemia, without other associated clinical features.  We performed whole exome sequencing in the affected child and segregation analysis within the family, which revealed a novel homozygous missense mutation in TRPM6, which was confirmed as a heterozygous allele in both parents and two younger siblings who had transient hypomagnesaemia. Using in silico modelling, we provide evidence that the missense variant p.(K1098E) in TRPM6 is pathogenic, as it disrupts stabilising TRP domain interactions. Management of familial hypomagnesaemia relies on prompt recognition, early magnesium replacement and lifelong monitoring.

Safety of a Triple-chamber Bag Parenteral Nutrition in Children Ages up to 24 Months: An Observational Study

OBJECTIVES

Hypermagnesemia has been reported in preterm neonates treated with commercial pediatric triple-chamber bag (3CB) parenteral nutrition (PN). This postmarketing study was requested by the European Medicines Agency to assess the safety of a 3CB PN product in full-term neonates and children up to 24 months of age.

METHODS

This prospective, multicenter, observational study enrolled hospitalized, full-term, newborn infants and children up to 24 months of age receiving >70% of nutrition as PN and requiring ≥50% of nutrition as PN for ≥5 days. All patients received 3CB PN during the study for ≤15 days. The primary outcome was serum magnesium, summarized by age group (0-1, >1-12, and >12-24 months). Secondary outcomes were nutritional intake and adverse events (AEs), including clinically significant abnormal laboratory results and vital signs.

RESULTS

A total of 102 eligible patients were included. Median (interquartile range) parenteral magnesium intake was 0.23 (0.18-0.30) mmol · kg · day. Mean serum magnesium showed no consistent changes during treatment in any age group. One moderate and 3 mild AEs of hypermagnesemia were reported in 4 patients (3.9%), all ages 0 to 1 month. Other AEs in >2 patients were hypertriglyceridemia (6.9%), laryngitis (3.9%), hyperkalemia, hypokalemia, hyponatremia, hypophosphatemia, and neonatal hypotension (each 2.9%). Other serum electrolytes were stable, and revealed no safety concerns.

CONCLUSIONS

Mean serum magnesium levels were not affected by 3CB PN in full-term neonates and children up to 24 months of age. The risk of hypermagnesemia AEs was low when providing median parenteral magnesium of 0.2 to 0.3 mmol · kg · day in this population.

Age and Muscle Function Are More Closely Associated With Intracellular Magnesium, as Assessed by 31P Magnetic Resonance Spectroscopy, Than With Serum Magnesium

Total serum magnesium is a common clinical measurement for assessing magnesium status; however, magnesium in blood represents less than 1% of the body's total magnesium content. We measured intramuscular ionized magnesium by phosphorus magnetic resonance spectroscopy (³¹P-MRS) and tested the hypothesis that this measure better correlates with skeletal muscle function and captures more closely the effect of aging than the traditional measure of total serum magnesium. Data were collected from 441 participants (age 24-98 years) in the Baltimore Longitudinal Study of Aging (BLSA), a study of normative aging that encompasses a broad age range. Results showed that intramuscular ionized magnesium was negatively associated with age (β = -0.29, p < 0.001, R ² = 0.08) and positively associated with knee-extension strength (β = 0.31, p < 0.001, and R ² = 0.1 in women; and β = 0.2, p = 0.003, and R ² = 0.04 in men), while total serum magnesium showed no association with age or strength (p = 0.27 and 0.1, respectively). Intramuscular ionized magnesium was significantly lower in women that in men (p < 0.001), perhaps due to chronic latent Mg deficiency in women that is not otherwise detected by serum magnesium levels. Based on these findings, we suggest that intramuscular ionized magnesium from ³¹P-MRS is a better clinical measure of magnesium status than total serum magnesium, and could be measured when muscle weakness of unidentified etiology is detected. It may also be used to monitor the effectiveness of oral magnesium interventions, including supplementation.

On uranium 234U and 238U radionuclides in calcium and magnesium supplements and the potential effective radiation dose assessment to the consumers

In this survey the concentrations of the radioactive nuclides uranium ²³⁴U and ²³⁸U were determined in the most popular calcium and magnesium supplements for adults in Poland. It was also investigated whether the supplements contain uranium isotopes and could be a potential source in the human diet and have an influence on the value of effective radiation doses to the consumers. The analyzed calcium and magnesium pharmaceuticals contained organic or inorganic compounds, several of natural origin as mussel's shells, fish extracts, or sedimentary rocks. As results showed, ²³⁴U and ²³⁸U concentrations in natural origin calcium and magnesium supplements were significantly higher than in other, synthetic ones. The highest ²³⁴U and ²³⁸U activity concentrations were determined in tablets from mussel's shells. The radiochemical hazard was assessed and the highest annual radiation dose was found in ²³⁴U and ²³⁸U present in supplements produced from shells or dolomite rock.

Magnesium Bioavailability and Tolerability Do Not Differ between Two Supplements with Different Release Properties

Magnesium (Mg²⁺) is one of the most frequently supplemented micronutrients. Due to possible gastrointestinal side effects, the European Food Safety Authority and the Institute of Medicine set the upper intake level for Mg²⁺ from supplements to 250 and 350 mg, respectively. Nevertheless, systematic data concerning the tolerability of Mg²⁺ supplements are scarce. The aim of the study was to directly compare the bioavailability and tolerability of two 500 mg Mg²⁺ supplements in a crossover study with duplicate determination. The different release properties were either a direct release (one phase) or a delayed release of the second half (two phases). An open-label, controlled trial with a crossover design, duplicate determination, and one-week washout phases was conducted. The participants ingested the test product after overnight fasting. Blood samples were taken at baseline and after 1, 2, 3, 4, 6, and 8 hours, and urine was collected over a period of 24 hours. The participants were on standardized nutrition during all examination days. There were no significant differences between the test products regarding 24-hour renal Mg²⁺ excretion and area under the curve of serum Mg²⁺ levels for 8 hours. Both test products were well tolerated with a very low frequency of gastrointestinal adverse effects and no significant differences between the test products. The Mg²⁺ bioavailability did not differ between the test products. The supplements examined had the same good tolerability. Both test products are therefore suited to enhance Mg²⁺ supply without relevant side effects.

Cross-sectional associations of dietary and circulating magnesium with skeletal muscle mass in the EPIC-Norfolk cohort

BACKGROUND

Maintenance of skeletal muscle in older age is critical to reducing frailty and the risk of falls and fractures. Nutrition has established importance for muscle health in general, but less research has looked at associations of dietary intake of specific micronutrients on skeletal muscle mass in older adults.

AIMS

This study aimed to investigate the influence of dietary and circulating magnesium on skeletal muscle mass in a UK population of 14,340 middle to older-aged men and women participating in the EPIC-Norfolk cohort study.

METHODS

Dietary nutrient intakes were estimated from 7-day food diaries and fat-free mass (FFM) by bioelectrical impedance analysis. Multivariable regression was used to investigate associations of FFM-based indices of muscle mass with quintiles of dietary magnesium intake or serum magnesium concentration groups. All analyses were stratified by sex, and regression models were adjusted for relevant covariates.

RESULTS

Significant positive trends in FFM measures were evident across magnesium dietary intake quintiles for both sexes (all p < 0.001; n = 6350 men; n = 7990 women) and both <60 and ≥ 60 year olds, with all-age quintile 5 versus quintile 1 maximal differences of 4.6% in men and 6.3% in women; highly relevant compared to the estimated 1% decline per year after 40 years of age. These observations were not reflected in serum magnesium analyses, where no consistent trends were found across the skeletal muscle mass indices tested.

CONCLUSION

Further investigation will be required to improve our understanding of the relationship between serum magnesium concentration and skeletal muscle mass. However, this study has demonstrated strong associations between dietary magnesium intake and indices of skeletal muscle mass in a UK population of middle to older-aged adults, highlighting the likely importance of dietary magnesium for optimal muscle health in this population.

Increased NEFA levels reduce blood Mg2+ in hypertriacylglycerolaemic states via direct binding of NEFA to Mg2

AIMS/HYPOTHESIS

The blood triacylglycerol level is one of the main determinants of blood Mg2+ concentration in individuals with type 2 diabetes. Hypomagnesaemia (blood Mg2+ concentration <0.7 mmol/l) has serious consequences as it increases the risk of developing type 2 diabetes and accelerates progression of the disease. This study aimed to determine the mechanism by which triacylglycerol levels affect blood Mg2+ concentrations.

METHODS

Using samples from 285 overweight individuals (BMI >27 kg/m2) who participated in the 300-Obesity study (an observational cross-sectional cohort study, as part of the Human Functional Genetics Projects), we investigated the association between serum Mg2+ with laboratory variables, including an extensive lipid profile. In a separate set of studies, hyperlipidaemia was induced in mice and in healthy humans via an oral lipid load, and blood Mg2+, triacylglycerol and NEFA concentrations were measured using colourimetric assays. In vitro, NEFAs harvested from albumin were added in increasing concentrations to several Mg2+-containing solutions to study the direct interaction between Mg2+ and NEFAs.

RESULTS

In the cohort of overweight individuals, serum Mg2+ levels were inversely correlated with triacylglycerols incorporated in large VLDL particles (r = -0.159, p ≤ 0.01). After lipid loading, we observed a postprandial increase in plasma triacylglycerol and NEFA levels and a reciprocal reduction in blood Mg2+ concentration both in mice (Δ plasma Mg2+ -0.31 mmol/l at 4 h post oral gavage) and in healthy humans (Δ plasma Mg2+ -0.07 mmol/l at 6 h post lipid intake). Further, in vitro experiments revealed that the decrease in plasma Mg2+ may be explained by direct binding of Mg2+ to NEFAs. Moreover, Mg2+ was found to bind to albumin in a NEFA-dependent manner, evidenced by the fact that Mg2+ did not bind to fatty-acid-free albumin. The NEFA-dependent reduction in the free Mg2+ concentration was not affected by the presence of physiological concentrations of other cations.

CONCLUSIONS/INTERPRETATION

This study shows that elevated NEFA and triacylglycerol levels directly reduce blood Mg2+ levels, in part explaining the high prevalence of hypomagnesaemia in metabolic disorders. We show that blood NEFA level affects the free Mg2+ concentration, and therefore, our data challenge how the fractional excretion of Mg2+ is calculated and interpreted in the clinic.

Serum magnesium level and hematoma expansion in patients with intracerebral hemorrhage

Spontaneous intracerebral hemorrhage (ICH) is a devastating subtype of stroke that results in significant rates of mortality and morbidities. The initial hematoma volume, hematoma expansion (HE), blood pressure (BP), and coagulopathy are considered strong predictors of clinical outcomes and mortality. Low serum magnesium (Mg⁺⁺) levels have been shown to be associated with larger initial hematoma and greater HE. Coagulopathy, platelet dysfunction, high BP, and increased inflammatory response might form the mechanistic link between low serum Mg⁺⁺ levels, larger hematoma size and greater HE. However, randomized clinical trials administering intravenous Mg⁺⁺ have shown no benefit over placebo in ICH patients. The confounding effect of hypocalcemia and a delay in Mg⁺⁺ trafficking across the blood-brain barrier might explain the futile results for intravenous Mg⁺⁺ therapy. In the current review, we will discuss the evidence regarding the possible role of low serum Mg⁺⁺ level on HE in acute ICH.

Extreme hypomagnesemia: characteristics of 119 consecutive inpatients

Extreme hypomagnesemia (hypoMg) can be encountered in many situations, but little data currently exist. Our aim is to describe the epidemiological, clinical, etiological characteristics, and the biological abnormalities of consecutive inpatients with extreme hypomagnesemia. In our observational monocentric study, between 1st July 2000 and April 2015, all inpatients with extreme hypomagnesemia, defined by at least one plasma magnesium concentration (P_Mg) below 0.3 mmol/L, were included. Demographic, clinical, biological characteristics and the drugs prescribed before the qualifying P_Mg measurement were retrospectively collected. 41,069 patients had at least one P_Mg assessment. The prevalence of extreme hypomagnesemia is 0.3% (119 inpatients). The median age is 70 years, 52% are women. The patients were mainly hospitalized in intensive care (n = 37, 31.1%), oncology (n = 21, 17.6%), gastroenterology (n = 18, 15.1%) and internal medicine (n = 16, 13.4%) departments. One hundred patients (84%) had a medical history of gastrointestinal disease (39% with bowel resections, 24% with stoma), and 50 (42%) had a cancer history. The drugs most commonly prescribed (known to induce hypoMg) are proton pump inhibitors (PPI) (n = 77, 70%), immunosuppressive regimens (n = 25, 22.5%), platinum salt-based chemotherapies (n = 19, 17.1%), and diuretics (n = 22, 19.8%). The suspected causes of hypomagnesemia are often multiple, but drugs (46%, including PPI in 19%) and chronic gastrointestinal disorders (37%) are prominent. Associated electrolyte disturbances include hypocalcemia (77%) and mild hypokalemia (51%). The 1-month mortality from all causes is 16%. Extreme hypomagnesemia is rare in inpatients, and is frequently associated with severe hypocalcemia. Digestive disorders and drugs are the main contributory causes.

Severely low serum magnesium is associated with increased risks of positive anti-thyroglobulin antibody and hypothyroidism: A cross-sectional study

Trace elements, such as iodine and selenium, are closely related to autoimmune thyroiditis and thyroid function. Low serum magnesium is associated with several chronic diseases; however, its associations with autoimmune thyroiditis and thyroid function are unclear. We investigated the relationships between low serum magnesium, autoimmune thyroiditis, and thyroid function in 1,257 Chinese participants. Demographic data were collected via questionnaires, and levels of serum thyroid stimulating hormone, anti-thyroid peroxidase antibody, anti-thyroglobulin antibody (TGAb), free thyroxine, serum magnesium, serum iodine, and urinary iodine concentration were measured. Participants were divided into serum magnesium level quartiles (≤0.55, 0.551-0.85, 0.851-1.15, and >1.15 mmol/L). The median serum magnesium level was 0.89 (0.73-1.06) mmol/L; levels ≤0.55 mmol/L were considered severely low (5.9% of participants). The risks of TGAb positivity and Hashimoto thyroiditis (HT) diagnosed using ultrasonography in the lowest quartile group were higher than those in the adequate magnesium group (0.851-1.15 mmol/L) (p < 0.01, odds ratios [ORs] = 2.748-3.236). The risks of total and subclinical-only hypothyroidism in the lowest quartile group were higher than those in the adequate magnesium group (0.851-1.15 mmol/L) (p < 0.01, ORs = 4.482-4.971). Severely low serum magnesium levels are associated with an increased rate of TGAb positivity, HT, and hypothyroidism.

Dietary Micronutrient and Mineral Intake in the Mediterranean Healthy Eating, Ageing, and Lifestyle (MEAL) Study

BACKGROUND

Dietary vitamins and minerals are essential compounds for the proper functioning of metabolic enzymes, regulation of gene transcription, and powering the body&rsquo;s defense against oxidative stress. The aim of the present study was to investigate micronutrient consumption separately by age and sex, major dietary sources, and percentage of individuals meeting the recommended requirements according to Italian (Livelli di Assunzione di Riferimento di Nutrienti (LARN)) and European (European Food Safety Agency (EFSA)) agencies.

METHODS

Data were obtained from the Mediterranean Healthy Eating, Ageing, and Lifestyle (MEAL) study, which included a sample of 1838 individuals randomly collected in the city of Catania, southern Italy. A validated food frequency questionnaire was used to collect information on diet.

RESULTS

Intake of vitamin A, vitamin C, and vitamin B group (except vitamin B9) was in line with other reports and was adequate according to the guidelines, while the percentage of individuals meeting the guidelines for vitamin D, vitamin E, and vitamin B9 was about 3%, 10%, and 40%, respectively. Among minerals, intake of iron, magnesium, and selenium was adequate for most of the sample, while the percentage of individuals meeting the recommendations for calcium, sodium, and potassium intake was about 20%, 8%, and 35%, respectively.

CONCLUSIONS

An important percentage of the population would benefit from campaigns raising awareness of micronutrient deficiency or excessive consumption potentially affecting their health.

Dialium seed coprophagy in wild western gorillas: Multiple nutritional benefits and toxicity reduction hypotheses

Unraveling the relationship between the unusual feeding behaviors and the nutritional intake of endangered species may provide crucial information for understanding species response to habitat unpredictable changes. Primates occasionally re-ingest fruit seeds alongside ingestion of feces, a behavior called coprophagy. The nutritional benefit is one of the several non-mutual exclusive hypotheses proposed to explain this behavior. We investigated the ecological correlates of coprophagy in wild western gorillas. We tested whether coprophagy occurred during periods of lower fruit availability and whether it led to higher nutrient intake in comparison to the other food. Data integrated phenological, fecal and nutritional analyses of gorilla food with behavioral observations collected at two sites in Central Africa (Mbeli Bai: ad libitum observations on 15 groups/solitary males, October 2002-November 2005; Bai Hokou: 5-min scan on a habituated group, December 2004-December 2005). Coprophagy occurred at the end of the high-fruiting season in association of two Dialium species. Coprophagy correlated positively with the occurrence of Dialium spp. fruit in gorilla feces and in the feeding scans, and showed a positive trend with Dialium availability but not with total fruit availability. Nutritional comparison of Dialium seeds with other important gorilla food showed higher fat and mineral content, particularly of Mg, but also of phenols and tannins in Dialium seeds. We discuss how the effect of gut processing and gut heat via coprophagy may act as cooking-like effect: increasing the ability to maximize nutrient intake by concurrently softening fibers and decreasing the toxic effect of antifeedants, like in human traditional cooking. Our results support both the multiple nutritional benefit hypothesis and the toxicity reduction hypothesis. Since Dialium is precious timber, the importance of this tree for the critically endangered western gorillas should be taken with high consideration when planning controlled logging of degraded forests or in face of habitat changes.

In vitro study of the inflammatory cells response to biodegradable Mg-based alloy extract

Biodegradable Mg-based alloys have shown great potential as bone fixation devices or vascular stents. As implant biomaterials, the foreign body reaction (FBR) is an important issue to be studied, where the inflammatory cells play a key role. Here, we used two inflammatory cell lines i.e. THP-1 cells and THP-1 macrophages, to evaluate the effect of Mg–Nd–Zn–Zr alloy (denoted as JDBM) extracts on cell viability, death modes, cell cycle, phagocytosis, differentiation, migration and inflammatory response. The results showed that high-concentration extract induced necrosis and complete damage of cell function. For middle-concentration extract, cell apoptosis and partially impaired cell function were observed. TNF-α expression of macrophages was up-regulated by co-culture with extract in 20% concentration, but was down-regulated in the same concentration in the presence of LPS stimulation. Interestingly, the production of TNF-α decreased when macrophages were cultured in middle and high concentration extracts independent of LPS. Cell viability was also negatively affected by magnesium ions in JDBM extracts, which was a potential factor affecting cell function. Our results provide new information about the impact of Mg alloy extracts on phenotype of immune cells and the potential mechanism, which should be taken into account prior to clinical applications.

Dietary Magnesium May Be Protective for Aging of Bone and Skeletal Muscle in Middle and Younger Older Age Men and Women: Cross-Sectional Findings from the UK Biobank Cohort

Although fragility fractures, osteoporosis, sarcopenia, and frailty are becoming more prevalent in our aging society the treatment options are limited and preventative strategies are needed. Despite magnesium being integral to bone and muscle physiology, the relationship between dietary magnesium and skeletal muscle and bone health has not been investigated concurrently to date. We analysed cross-sectional associations between dietary magnesium and skeletal muscle mass (as fat free mass-FFM), grip strength, and bone density (BMD) in 156,575 men and women aged 39-72 years from the UK Biobank cohort. FFM was measured with bioelectrical impedance and was expressed as the percentage of body weight (FFM%) or as divided by body mass index (FFMBMI). Adjusted mean grip strength, FFM%, FFMBMI, and BMD were calculated according to quintiles of dietary magnesium, while correcting for covariates. Significant inter-quintile differences across intakes of magnesium existed in men and women, respectively, of 1.1% and 2.4% for grip strength, 3.0% and 3.6% for FFM%, 5.1% and 5.5% for FFMBMI, and 2.9% and 0.9% for BMD. These associations are as great or greater than annual measured losses of these musculoskeletal outcomes, indicating potential clinical significance. Our study suggests that dietary magnesium may play a role in musculoskeletal health and has relevance for population prevention strategies for sarcopenia, osteoporosis, and fractures.

Intestinal Absorption and Factors Influencing Bioavailability of Magnesium-An Update

Background:

Information on the bioavailability of the essential mineral Mg2+ is sparse.

Objective/Method:

Evaluation of the present knowledge on factors influencing the bioavailability and intestinal absorption of Mg2+.

Results:

Mg2+ is absorbed via a paracellular passive and a transcellular active pathway that involves TRPM6/7 channel proteins. The bioavailability of Mg2+ varies within a broad range, depending on the dose, the food matrix, and enhancing and inhibiting factors. Dietary factors impairing Mg2+ up-take include high doses of other minerals, partly fermentable fibres (e.g., hemicellulose), non-fermentable fibres (e.g., cellulose, lignin), phytate and oxalate, whereas proteins, medium-chain-triglycerides, and low- or indigestible carbohydrates (e.g., resistant starch, oligosaccharides, inulin, mannitol and lactulose) enhance Mg2+ uptake. The Mg2+ dose is a major factor controlling the amount of Mg2+ absorbed. In principle, the relative Mg2+ uptake is higher when the mineral is in-gested in multiple low doses throughout the day compared to a single, large intake of Mg2+. The type of Mg2+ salt appears less relevant than is often thought. Some studies demonstrated a slightly higher bioavailability of organic Mg2+ salts compared to inorganic compounds under standardized conditions, whereas other studies did not.

Conclusion:

Due to the lack of standardized tests to assess Mg2+ status and intestinal absorption, it remains unclear which Mg2+ binding form produces the highest bioavailability. The Mg2+ intake dose combined with the endogenous Mg2+ status is more important. Because Mg2+ cannot be stored but only retained for current needs, a higher absorption is usually followed by a higher excretion of the mineral.

Low serum magnesium levels are associated with increased risk of fractures: a long-term prospective cohort study

Magnesium, which is an essential trace element that plays a key role in several cellular processes, is a major component of bone; however, its relationship with risk of major bone fractures is uncertain. We aimed to investigate the association of baseline serum magnesium concentrations with risk of incident fractures. We analyzed data on 2245 men aged 42-61 years in the Kuopio Ischemic Heart Disease prospective cohort study, with the assessment of serum magnesium measurements and dietary intakes made at baseline. Hazard ratios [95% confidence intervals (CI)] for incident total (femoral, humeral, and forearm) and femoral fractures were assessed. During a median follow-up of 25.6 years, 123 total fractures were recorded. Serum magnesium was non-linearly associated with risk of total fractures. In age-adjusted Cox regression analysis, the hazard ratio (HR) (95% CIs) for total fractures in a comparison of the bottom quartile versus top quartile of magnesium concentrations was 2.10 (1.30-3.41), which persisted on adjustment for several established risk factors 1.99 (1.23-3.24). The association remained consistent on further adjustment for renal function, socioeconomic status, total energy intake, and several trace elements 1.80 (1.10-2.94). The corresponding adjusted HRs for femoral fractures were 2.56 (1.38-4.76), 2.43 (1.30-4.53) and 2.13 (1.13-3.99) respectively. There was no evidence of an association of dietary magnesium intake with risk of any fractures. In middle-aged Caucasian men, low serum magnesium is strongly and independently associated with an increased risk of fractures. Further research is needed to assess the potential relevance of serum magnesium in the prevention of fractures.