Dietary magnesium intake influences circulating pro-inflammatory neuropeptide levels and loss of myocardial tolerance to postischemic stress

Magnesium and the Hallmarks of Aging

Magnesium is an essential ion in the human body that regulates numerous physiological and pathological processes. Magnesium deficiency is very common in old age. Age-related chronic diseases and the aging process itself are frequently associated with low-grade chronic inflammation, called 'inflammaging'. Because chronic magnesium insufficiency has been linked to excessive generation of inflammatory markers and free radicals, inducing a chronic inflammatory state, we formerly hypothesized that magnesium inadequacy may be considered among the intermediaries helping us explain the link between inflammaging and aging-associated diseases. We show in this review evidence of the relationship of magnesium with all the hallmarks of aging (genomic instability, telomere attrition, epigenetic alterations, loss of proteostasis, deregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, altered intercellular communication, disabled autophagy, dysbiosis, and chronic inflammation), which may positively affect the human healthspan. It is feasible to hypothesize that maintaining an optimal balance of magnesium during one's life course may turn out to be a safe and economical strategy contributing to the promotion of healthy aging. Future well-designed studies are necessary to further explore this hypothesis.

Exogeneous metal ions as therapeutic agents in cardiovascular disease and their delivery strategies

Metal ions participate in many metabolic processes in the human body, and their homeostasis is crucial for life. In cardiovascular diseases (CVDs), the equilibriums of metal ions are frequently interrupted, which are related to a variety of disturbances of physiological processes leading to abnormal cardiac functions. Exogenous supplement of metal ions has the potential to work as therapeutic strategies for the treatment of CVDs. Compared with other therapeutic drugs, metal ions possess broad availability, good stability and safety and diverse drug delivery strategies. The delivery strategies of metal ions are important to exert their therapeutic effects and reduce the potential toxic side effects for cardiovascular applications, which are also receiving increasing attention. Controllable local delivery strategies for metal ions based on various biomaterials are constantly being designed. In this review, we comprehensively summarized the positive roles of metal ions in the treatment of CVDs from three aspects: protecting cells from oxidative stress, inducing angiogenesis, and adjusting the functions of ion channels. In addition, we introduced the transferability of metal ions in vascular reconstruction and cardiac tissue repair, as well as the currently available engineered strategies for the precise delivery of metal ions, such as integrated with nanoparticles, hydrogels and scaffolds.

Bariatric Surgery and Inflammatory Bowel Disease: National Trends and Outcomes Associated with Procedural Sleeve Gastrectomy vs Historical Bariatric Surgery Among US Hospitalized Patients 2009-2020

PURPOSE

The association between bariatric surgery and IBD-related inpatient outcomes is not well characterized. We report, analyze, and compare inpatient trends and outcomes among encounters with a history of bariatric surgery (Hx-MBS) compared to those receiving bariatric surgery during index admission (PR-MBS) admitted from 2009 to 2020.

METHODS

Retrospective cohort design: the 2009-2020 National Inpatient Sample (NIS) databases were used to identify hospital encounters with patients aged ≥ 18 years with a history of MBS (Hx-MBS) or with procedure coding indicating MBS procedure (PR-MBS) according to International Classification of Diseases, Ninth (ICD-9-CM/ ICD-9-PCS) or Tenth Revision (ICD-10-CM/ICD-10-PCS) Clinical Modification/Procedure Coding System during index admission (ICD-9-CM: V4586; ICD-10-CM: Z9884; ICD-9-PR: 4382, 4389; ICD-10-PR: 0DB64Z3, 0DB63ZZ). Pearson χ2 analysis, analysis of variance, multivariable regression analyses, and propensity matching on independent variables were conducted to analyze significant associations between variables and for primary outcome inflammatory bowel disease-related admission, and secondary outcomes: diagnosis of nonalcoholic steatohepatitis, nonalcoholic fatty liver disease, or chronic mesenteric ischemia during admission.

RESULTS

We identified 3,365,784 (76.20%) Hx-MBS hospitalizations and 1,050,900 hospitalizations with PR-MBS (23.80%). Propensity score matching analysis demonstrated significantly higher odds of inflammatory bowel disease, and chronic mesenteric ischemia for Hx-MBS compared to PR-MBS, and significantly lower odds of nonalcoholic steatohepatitis and nonalcoholic fatty liver disease for Hx-MBS compared to PR-MBS.

CONCLUSION

In our study, Hx-MBS was associated with significantly increased odds of inflammatory bowel disease and other GI pathologies compared to matched controls. The mechanism by which this occurs is unclear. Additional studies are needed to examine these findings.

Magnesium-An Ion with Multiple Invaluable Actions, Often Insufficiently Supplied: From In Vitro to Clinical Research

Magnesium (Mg) is a key ion for numerous metabolic processes, being a cofactor of over 600 enzymes involved in cell metabolism and multiple biological processes [...].

Prognostic Value of Magnesium in COVID-19: Findings from the COMEPA Study

Magnesium (Mg) plays a key role in infections. However, its role in coronavirus disease 2019 (COVID-19) is still underexplored, particularly in long-term sequelae. The aim of the present study was to examine the prognostic value of serum Mg levels in older people affected by COVID-19. Patients were divided into those with serum Mg levels ≤1.96 vs. >1.96 mg/dL, according to the Youden index. A total of 260 participants (mean age 65 years, 53.8% males) had valid Mg measurements. Serum Mg had a good accuracy in predicting in-hospital mortality (area under the curve = 0.83; 95% CI: 0.74-0.91). Low serum Mg at admission significantly predicted in-hospital death (HR = 1.29; 95% CI: 1.03-2.68) after adjusting for several confounders. A value of Mg ≤ 1.96 mg/dL was associated with a longer mean length of stay compared to those with a serum Mg > 1.96 (15.2 vs. 12.7 days). Low serum Mg was associated with a higher incidence of long COVID symptomatology (OR = 2.14; 95% CI: 1.30-4.31), particularly post-traumatic stress disorder (OR = 2.00; 95% CI: 1.24-16.40). In conclusion, low serum Mg levels were significant predictors of mortality, length of stay, and onset of long COVID symptoms, indicating that measuring serum Mg in COVID-19 may be helpful in the prediction of complications related to the disease.

Magnesium in Aging, Health and Diseases

Several changes of magnesium (Mg) metabolism have been reported with aging, including diminished Mg intake, impaired intestinal Mg absorption and renal Mg wasting. Mild Mg deficits are generally asymptomatic and clinical signs are usually non-specific or absent. Asthenia, sleep disorders, hyperemotionality, and cognitive disorders are common in the elderly with mild Mg deficit, and may be often confused with age-related symptoms. Chronic Mg deficits increase the production of free radicals which have been implicated in the development of several chronic age-related disorders. Numerous human diseases have been associated with Mg deficits, including cardiovascular diseases, hypertension and stroke, cardio-metabolic syndrome and type 2 diabetes mellitus, airways constrictive syndromes and asthma, depression, stress-related conditions and psychiatric disorders, Alzheimer's disease (AD) and other dementia syndromes, muscular diseases (muscle pain, chronic fatigue, and fibromyalgia), bone fragility, and cancer. Dietary Mg and/or Mg consumed in drinking water (generally more bioavailable than Mg contained in food) or in alternative Mg supplements should be taken into consideration in the correction of Mg deficits. Maintaining an optimal Mg balance all through life may help in the prevention of oxidative stress and chronic conditions associated with aging. This needs to be demonstrated by future studies.

Magnesium in Infectious Diseases in Older People

Reduced magnesium (Mg) intake is a frequent cause of deficiency with age together with reduced absorption, renal wasting, and polypharmacotherapy. Chronic Mg deficiency may result in increased oxidative stress and low-grade inflammation, which may be linked to several age-related diseases, including higher predisposition to infectious diseases. Mg might play a role in the immune response being a cofactor for immunoglobulin synthesis and other processes strictly associated with the function of T and B cells. Mg is necessary for the biosynthesis, transport, and activation of vitamin D, another key factor in the pathogenesis of infectious diseases. The regulation of cytosolic free Mg in immune cells involves Mg transport systems, such as the melastatin-like transient receptor potential 7 channel, the solute carrier family, and the magnesium transporter 1 (MAGT1). The functional importance of Mg transport in immunity was unknown until the description of the primary immunodeficiency XMEN (X-linked immunodeficiency with Mg defect, Epstein–Barr virus infection, and neoplasia) due to a genetic deficiency of MAGT1 characterized by chronic Epstein–Barr virus infection. This and other research reporting associations of Mg deficit with viral and bacterial infections indicate a possible role of Mg deficit in the recent coronavirus disease 2019 (COVID-19) and its complications. In this review, we will discuss the importance of Mg for the immune system and for infectious diseases, including the recent pandemic of COVID-19.

Magnesium and Hypertension in Old Age

Hypertension is a complex condition in which various actors and mechanisms combine, resulting in cardiovascular and cerebrovascular complications that today represent the most frequent causes of mortality, morbidity, disability, and health expenses worldwide. In recent decades, there has been an exceptional number of experimental, epidemiological, and clinical studies confirming a close relationship between magnesium deficit and high blood pressure. Multiple mechanisms may help to explain the bulk of evidence supporting a protective effect of magnesium against hypertension and its complications. Hypertension increases sharply with advancing age, hence older persons are those most affected by its negative consequences. They are also more frequently at risk of magnesium deficiency by multiple mechanisms, which may, at least in part, explain the higher frequency of hypertension and its long-term complications. The evidence for a favorable effect of magnesium on hypertension risk emphasizes the importance of broadly encouraging the intake of foods such as vegetables, nuts, whole cereals and legumes, optimal dietary sources of magnesium, and avoiding processed foods, which are very poor in magnesium and other fundamental nutrients, in order to prevent hypertension. In some cases, when diet is not enough to maintain an adequate magnesium status, magnesium supplementation may be of benefit and has been shown to be well tolerated.

Experimental Hypomagnesemia Induces Neurogenic Inflammation and Cardiac Dysfunction

Hypomagnesemia occurs clinically as a result of restricted dietary intake, Mg-wasting drug therapies, chronic disease status and may be a risk factor in patients with cardiovascular disorders. Dietary restriction of magnesium (Mg deficiency) in animal models produced a pro-inflammatory/pro-oxidant condition, involving hematopoietic, neuronal, cardiovascular, renal and other systems. In Mg-deficient rodents, early elevations in circulating levels of the neuropeptide, substance P (SP) may trigger subsequent deleterious inflammatory/oxidative/nitrosative stress events. Evidence also suggests that activity of neutral endopeptidase (NEP, neprilysin), the major SP-degrading enzyme, may be impaired during later stages of Mg deficiency, and this may sustain the neurogenic inflammatory response. In this article, experimental findings using substance P receptor blockade, NEP inhibition, and N-methyl-D-aspartate (NMDA) receptor blockade demonstrated the connection between hypomagnesemia, neurogenic inflammation, oxidative stress and enhanced cardiac dysfunction. Proof of concept concerning neurogenic inflammation is provided using an isolated perfused rat heart model exposed to acute reductions in perfusate magnesium concentrations.

Prevention of Cardiovascular Disease: Screening for Magnesium Deficiency

Magnesium is an essential mineral naturally present in the human body, where it acts as cofactor in several enzymatic reactions. Magnesium is a key cardiovascular regulator, which maintains electrical, metabolic, and vascular homeostasis. Moreover, magnesium participates in inflammation and oxidative processes. In fact, magnesium deficiency is involved in the pathophysiology of arterial hypertension, diabetes mellitus, dyslipidemia, metabolic syndrome, endothelial dysfunction, coronary artery disease, cardiac arrhythmias, and sudden cardiac death. In consideration of the great public-health impact of cardiovascular disease, the recognition of the negative effects of magnesium deficiency suggests the possible role of hypomagnesaemia as cardiovascular risk factor and the use of serum magnesium level for the screening and prevention of cardiovascular risk factors and cardiovascular diseases. Moreover, it might help with the identification of new therapeutical strategies for the management of cardiovascular disease through magnesium supplementation.

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 Magnesium and Chronic Disease

Although official magnesium (Mg) dietary reference intakes are open to question, a significant number of adults likely have intakes that are in the range of 50%-99% of the requirement. This moderate or marginal (subclinical) deficient Mg intake generally is asymptomatic. Animal studies, however, indicate that moderate or subclinical Mg deficiency primes phagocytic cells for the release of proinflammatory cytokines leading to chronic inflammatory and oxidative stress. Human studies have found that dietary Mg is inversely related to serum or plasma C-reactive protein (CRP). Individuals with apparently deficient Mg intakes have an increased likelihood of serum or plasma CRP ≥3.0 mg/L, considered an indicator of chronic inflammatory stress that increases the risk for chronic disease. In addition, elevated serum or plasma CRP in individuals with chronic disease is decreased by Mg supplementation, which suggests that Mg decreases the risk for chronic disease. The importance of dietary Mg intake on the risk for chronic disease through affecting inflammatory and oxidative stress is supported by numerous meta-analyses and systematic reviews that have found dietary Mg is inversely associated with chronic diseases such hypertension, ischemic heart disease, stroke, metabolic syndrome, diabetes, and colorectal cancer.

Dietary Magnesium and Cardiovascular Disease: A Review with Emphasis in Epidemiological Studies

Magnesium (Mg) is an essential dietary element for humans involved in key biological processes. A growing body of evidence from epidemiological studies, randomized controlled trials (RCTs) and meta-analyses have indicated inverse associations between Mg intake and cardiovascular diseases (CVD). The present review aims to summarize recent scientific evidence on the topic, with a focus on data from epidemiological studies assessing the associations between Mg intake and major cardiovascular (CV) risk factors and CVD. We also aimed to review current literature on circulating Mg and CVD, as well as potential biological processes underlying these observations. We concluded that high Mg intake is associated with lower risk of major CV risk factors (mainly metabolic syndrome, diabetes and hypertension), stroke and total CVD. Higher levels of circulating Mg are associated with lower risk of CVD, mainly ischemic heart disease and coronary heart disease. Further, RCTs and prospective studies would help to clarify whether Mg intake and Mg circulating levels may also protect against other CVDs and CVD death.

Magnesium deficiency and increased inflammation: current perspectives

Animal studies have shown that magnesium deficiency induces an inflammatory response that results in leukocyte and macrophage activation, release of inflammatory cytokines and acute-phase proteins, and excessive production of free radicals. Animal and in vitro studies indicate that the primary mechanism through which magnesium deficiency has this effect is through increasing cellular Ca²⁺, which is the signal that results in the priming of cells to give the inflammatory response. Primary pro-inflammatory cytokines such as tumor necrosis factor-α and interleukin (IL)-1; the messenger cytokine IL-6; cytokine responders E-selectin, intracellular adhesion molecule-1 and vascular cell adhesion molecule-1; and acute-phase reactants C-reactive protein and fibrinogen have been determined to associate magnesium deficiency with chronic low-grade inflammation (inflammatory stress). When magnesium dietary intake, supplementation, and/or serum concentration suggest/s the presence of magnesium deficiency, it often is associated with low-grade inflammation and/or with pathological conditions for which inflammatory stress is considered a risk factor. When magnesium intake, supplementation, and/or serum concentration suggest/s an adequate status, magnesium generally has not been found to significantly affect markers of chronic low-grade inflammation or chronic disease. The consistency of these findings can be modified by other nutritional and metabolic factors that affect inflammatory and oxidative stress. In spite of this, findings to date provide convincing evidence that magnesium deficiency is a significant contributor to chronic low-grade inflammation that is a risk factor for a variety of pathological conditions such as cardiovascular disease, hypertension, and diabetes. Because magnesium deficiency commonly occurs in countries where foods rich in magnesium are not consumed in recommended amounts, magnesium should be considered an element of significant nutritional concern for health and well-being in these countries.

Low levels of serum magnesium are associated with poststroke cognitive impairment in ischemic stroke patients

PURPOSE

Population-based studies have revealed a high prevalence of cognitive impairment after stroke. We aimed to determine the impact of serum magnesium (Mg²⁺) levels on the occurrence of poststroke cognitive impairment (PSCI).

PATIENTS AND METHODS

Acute ischemic stroke patients (n = 327) were enrolled in our study and serum Mg²⁺ levels were assessed on admission. The cognitive performance of each patient was evaluated using the Mini-Mental State Examination (MMSE) at a 1-month follow-up visit.

RESULTS

One hundred five (32.1%) patients were diagnosed with PSCI at 1-month poststroke. The serum Mg²⁺ levels in both the PSCI group and the non-PSCI group were significantly lower than those in normal control group (P<0.001). In addition, the PSCI group had lower levels of serum Mg²⁺ compared to the non-PSCI group (P=0.003). In the binary logistic regression analysis, a serum Mg²⁺ level of ≤0.82 mmol/L was significantly associated with an increased risk of developing PSCI by the 1-month follow-up (OR 2.236, 95% CI 1.232-4.058, P=0.008), as was age (OR 1.043, 95% CI 1.014-1.073, P=0.003).

CONCLUSION

Our results demonstrate the existence of a significant association between low levels of serum Mg²⁺ and the occurrence of PSCI 1-month poststroke, and these results suggest that low levels of serum Mg²⁺ on admission may serve as a risk factor for developing PSCI by 1-month poststroke.

Correlation of magnesium deficiency with C-reactive protein in elective cardiac surgery with cardiopulmonary bypass for ischemic heart disease

BACKGROUND AND OBJECTIVE

Cardiac surgery is associated with systemic inflammatory response, which is triggered by cardiopulmonary bypass (CPB) and possibly with underlying magnesium deficiency. Animal studies have shown that magnesium deficiency intensifies oxidative stress and inflammatory processes. We aimed to find a link between serum, erythrocyte, cardiac tissue magnesium concentration and C-reactive protein (CRP) as an inflammatory marker in patients undergoing elective cardiac surgery with CPB.

MATERIALS AND METHODS

The data of 27 patients undergoing elective cardiac surgery with CPB for ischemic heart disease were analyzed. Measurements were taken at the baseline, i.e., 24 h before surgery (serum magnesium, CRP); time point 1, before CPB (serum, erythrocyte and cardiac tissue magnesium); time point 2, after CPB (serum, erythrocyte and cardiac tissue magnesium), and time point 3, 15-17 h after surgery (serum, erythrocyte magnesium, CRP).

RESULTS

There was a negative correlation between baseline serum magnesium and baseline CRP (P=0.009; r=-0.492), negative correlation between cardiac tissue magnesium at the time point 1 and baseline CRP (P=0.021; r=-0.443), and positive correlation between CRP at time point 3 and erythrocyte magnesium at time point 2 (P<0.001; r=0.637).

CONCLUSIONS

The data of our study verify that inflammatory marker CRP and magnesium concentration in serum and cardiac tissue before the surgery are inversely related in patients undergoing elective cardiac surgery with CPB. Well-planned further studies are needed to evaluate the importance of underlying magnesium deficiency on the severity of systemic inflammatory response and postoperative complications after surgery with CPB.

EGFR-TKI, erlotinib, causes hypomagnesemia, oxidative stress, and cardiac dysfunction: attenuation by NK-1 receptor blockade

To determine whether the epidermal growth factor receptor tyrosine kinase inhibitor, erlotinib may cause hypomagnesemia, inflammation, and cardiac stress, erlotinib was administered to rats (10 mg · kg(-1)· d(-1)) for 9 weeks. Plasma magnesium decreased progressively between 3 and 9 weeks (-9% to -26%). Modest increases in plasma substance P (SP) occurred at 3 (27%) and 9 (25%) weeks. Neutrophil superoxide-generating activity increased 3-fold, and plasma 8-isoprostane rose 210%, along with noticeable appearance of cardiac perivascular nitrotyrosine. The neurokinin-1 (NK-1) receptor antagonist, aprepitant (2 mg · kg(-1) · d(-1)), attenuated erlotinib-induced hypomagnesemia up to 42%, reduced circulating SP, suppressed neutrophil superoxide activity and 8-isoprostane elevations; cardiac nitrotyrosine was diminished. Echocardiography revealed mild to moderately decreased left ventricular ejection fraction (-11%) and % fractional shortening (-17%) by 7 weeks of erlotinib treatment and significant reduction (-17.5%) in mitral valve E/A ratio at week 9 indicative of systolic and early diastolic dysfunction. Mild thinning of the left ventricular posterior wall suggested early dilated cardiomyopathy. Aprepitant completely prevented the erlotinib-induced systolic and diastolic dysfunction and partially attenuated the anatomical changes. Thus, chronic erlotinib treatment does induce moderate hypomagnesemia, triggering SP-mediated oxidative/inflammation stress and mild-to-moderate cardiac dysfunction, which can largely be corrected by the administration of the SP receptor blocker.

Dietary intake of magnesium may modulate depression

Depressive symptoms are frequent in students and may lead to countless problems. Several hypotheses associate magnesium with depression because of the presence of this mineral in several enzymes, hormones, and neurotransmitters, which may play a key role in the pathological pathways of depression. The aim of this study was to assess whether magnesium intake could modulate depressive symptoms. A cross-sectional study was conducted on a convenience sample of 402 Iranian postgraduate students studying in Malaysia to assess the relationship between magnesium intake and depressive symptoms. The mean age of the participants was 32.54 ± 6.22 years. The results of the study demonstrated an inverse relationship between magnesium intake and depressive symptoms, which persisted even after adjustments for sex, age, body mass index, monthly expenses, close friends, living on campus, smoking (current and former), education, physical activity, and marital status.

Differences in nutrition status by body mass index in patients with peripheral artery disease

Peripheral Arterial Disease (PAD) is most prevalent in the elderly and associated with increased cardio vascular disease (CVD) morbidity and mortality. Treatment focuses on improving functional capacity and reducing CVD risk factors. To date, little is understood about dietary habits and weight in this patient population. Nutritional and weight recommendations are based on heart health, and little is known about the unique needs of elderly PAD patients with multiple comorbidities. This prospective study compared 1) the dietary intake of nonobese PAD patients in comparison with those who were obese and; 2) dietary intake of those patients with the Estimated Average Requirement (EAR) based on age, gender and BMI. Nutritional intake was assessed with the Block 98 Food Frequency Questionnaire. Body mass index (BMI) was calculated in accordance with the National Heart, Lung, and Blood Institute (NHLBI) guidelines.The study population was divided into obese (BMI ≥ 30) and nonobese (NO) groups. Comparisons between groups were performed using the Mann-Whitney U test for continuous variables and the Chi-square test for ordinal variables. All tests were two-tailed and P < 0.05 was considered significant. The Estimated Average Requirement (EAR) cut-point method was used to compare nutritional variables with Dietary Reference Intakes (DRI). The study population included 189 NO (BMI < 30) and 111 obese (BMI > 30) individuals. Obese participants reported greater intake of foods containing cholesterol and trans-fatty acids and more frequent intake of B vitamins in comparison with the NO BMI group. Additionally, the nutrient intake of all participants by age, gender and BMI was lower than the EAR for magnesium, folate, and Vitamin E. These results suggest that the nutritional intake of PAD patients differs based on gender and BMI. Additionally, EAR was lower for specific nutrients than recommended. Further investigation is needed to examine the association between nutritional intake and nutrition-related deficits.

Hypomagnesemia and inflammation: clinical and basic aspects

In recent years, increasing awareness of hypomagnesemia has resulted in clinical trials that associate this mineral deficiency with diabetes, metabolic syndrome, and drug therapies for cancer and cardiovascular diseases. However, diagnostic testing for tissue deficiency of magnesium still presents a challenge. Investigations of animal and cellular responses to magnesium deficiency have found evidence of complex proinflammatory pathways that may lead to greater understanding of mediators of the pathobiology in neuronal, cardiovascular, intestinal, renal, and hematological tissues. The roles of free radicals, cytokines, neuropeptides, endotoxin, endogenous antioxidants, and vascular permeability, and interventions to limit the inflammatory response associated with these parameters, are outlined in basic studies of magnesium deficiency. It is hoped that this limited review of inflammation associated with some diseases complicated by magnesium deficiency will prompt greater awareness by clinicians and other health providers and in turn increase efforts to prevent and treat this disorder.

The role of magnesium deficiency in cardiovascular and intestinal inflammation

Hypomagnesemia continues to cause difficult clinical problems, such as significant cardiac arrhythmias where intravenous magnesium therapy can be lifesaving. Nutritional deficiency of magnesium may present with some subtle symptoms such as leg cramps and occasional palpitation. We have investigated dietary-induced magnesium deficiency in rodent models to assess the pathobiology associated with prolonged hypomagnesemia. We found that neuronal sources of the neuropeptide, substance P (SP), contributed to very early prooxidant/proinflammatory changes during Mg deficiency. This neurogenic inflammation is systemic in nature, affecting blood cells, cardiovascular, intestinal, and other tissues, leading to impaired cardiac contractility similar to that seen in patients with heart failure. We have used drugs that block the release of SP from neurons and SP-receptor blockers to prevent some of these pathobiological changes; whereas, blocking SP catabolism enhances inflammation. Our findings emphasize the essential role of this cation in preventing cardiomyopathic changes and intestinal inflammation in a well-studied animal model, and also implicate the need for more appreciation of the potential clinical relevance of optimal magnesium nutrition and therapy.

Magnesium, inflammation, and obesity in chronic disease

About 60% of adults in the United States do not consume the estimated average requirement for magnesium, but widespread pathological conditions attributed to magnesium deficiency have not been reported. Nevertheless, low magnesium status has been associated with numerous pathological conditions characterized as having a chronic inflammatory stress component. In humans, deficient magnesium intakes are mostly marginal to moderate (approximately 50% to <100% of the recommended dietary allowance). Animal experiments indicate that signs of marginal-to-moderate magnesium deficiency can be compensated or exacerbated by other factors influencing inflammatory and oxidative stress; recent studies suggest a similar happening in humans. This suggestion may have significance in obesity, which is characterized as having a chronic low-grade inflammation component and an increased incidence of a low magnesium status. Marginal-to-moderate magnesium deficiency through exacerbating chronic inflammatory stress may be contributing significantly to the occurrence of chronic diseases such as atherosclerosis, hypertension, osteoporosis, diabetes mellitus, and cancer.

Neurogenic inflammation and cardiac dysfunction due to hypomagnesemia

Hypomagnesemia continues to be a significant clinical disorder that is present in patients with diabetes mellitus, alcoholism, and treatment with magnesuric drugs (diuretics, cancer chemotherapy agents, etc.). To determine the role of magnesium in cardiovascular pathophysiology, we have used dietary restriction of this cation in animal models. This review highlights some key observations that helped formulate the hypothesis that release of substance P (SP) during experimental dietary Mg deficiency (MgD) may initiate a cascade of deleterious inflammatory, oxidative, and nitrosative events, which ultimately promote cardiomyopathy, in situ cardiac dysfunction, and myocardial intolerance to secondary stresses. SP acts primarily through neurokinin-1 receptors of inflammatory and endothelial cells, and may induce production of reactive oxygen and nitrogen species (superoxide anion, NO*, peroxynitrite, hydroxyl radical), leading to enhanced consumption of tissue antioxidants; stimulate release of inflammatory mediators; promote tissue adhesion molecule expression; and enhance inflammatory cell tissue infiltration and cardiovascular lesion formation. These SP-mediated events may predispose the heart to injury if faced with subsequent oxidative stressors (ischemia/reperfusion, certain drugs) or facilitate development of in situ cardiac dysfunction, especially with prolonged dietary Mg restriction. Significant protection against most of these MgD-mediated events has been observed with interventions that modulate neuronal SP release or its bioactivity, and with several antioxidants (vitamin E, probucol, epicaptopril, d-propranolol). In view of the clinical prevalence of hypomagnesemia, new treatments, beyond magnesium repletion, may be needed to diminish deleterious neurogenic and prooxidative components described in this article.

Effect of hypomagnesemia on allogeneic activation in mice

INTRODUCTION

Magnesium (Mg) plays an essential role in a wide range of fundamental cellular reactions. It has been reported that in rodents Mg-deficient diet-induced hypomagnesemia results in an early inflammation. We have previously shown that chronic severe hypomagnesemia was associated neither with endothelial cell activation nor with an inflammatory process which are crucial in the allograft rejection process. T cell allogeneic stimulation activates the phosphatase calcineurin which triggers the signaling pathways leading to IL-2 synthesis and lymphocyte proliferation. Full activation of calcineurin requires Mg. Surveys suggest that a significant number of people consume less Mg than the international dietary reference intakes leading to hypomagnesemia in 2.5% to 15% of the general population.

OBJECTIVE

The aim of the study was to investigate the effects of hypomagnesemia on lymphocyte allogeneic activation and proliferation in a murine model of dietary-induced hypomagnesemia.

METHODS

C57BL/6J (H-2(b), Mls(b)) mice were given normal Mg-containing diet (1400 ppm Mg, control mice), or synthetic Mg-deficient diets containing either 50 ppm Mg or 150 ppm Mg for 28 days. Serum Mg levels were determined at days 5, 14 and 28. In parallel, complete urine and faeces were collected by using metabolic cages during a 24 h period for Mg determinations. Splenocytes from C57BL/6 mice fed either normal diet or 50 ppm Mg-diet were used as responder cells in mixed lymphocyte reaction (MLR) performed with splenocytes from C3H/He mice (H-2(k), Mls(IIa)) and C57BL/6 mice fed normal diet as stimulators for allogeneic and isogeneic conditions, respectively. TGF-beta and IL-2 productions were quantified in the supernates of mixed splenocytes cultures. 3x10(6) splenocytes from mice fed 50 ppm Mg-diet were used for calcineurin activity determination at day 28.

RESULTS

In mice fed 150 ppm Mg-diet, moderate hypomagnesemia was observed from day 5 to day 28. Oral supplementation with Mg pidolate (5 or 20 mg Mg/kg/day) could not restore normal serum Mg levels. Serum Mg concentration early decreased in mice fed 50 ppm Mg-diet to achieve stabilized severe hypomagnesemia at days 14 and 28. Urine Mg concentration early dramatically fell down then stabilized in mice fed Mg-deficient diets. In MLR performed at day 28 with splenocytes from mice fed 50 ppm Mg-diet, proliferation and IL-2 production in allogeneic conditions were similar to control mice. No TGF-beta production was detected in any group. Lastly, calcineurin activity measured at day 28 was significantly lower in splenocyes from mice fed 50 ppm Mg-diet than in mice fed control diet.

CONCLUSION

Mg-deficiency does not alter splenocyte allogeneic activation and proliferation and IL-2 production in vitro, although it partially inhibits calcineurin activity. We hypothesize that the remaining activity is sufficient for IL-2 gene normal activation. Alternatively, Mg-deficiency may trigger other signaling pathways leading to IL-2 production.

Inhibition of neutral endopeptidase potentiates neutrophil activation during Mg-deficiency in the rat

Neutral endopeptidase (NEP), which degrades substance P (SP), may regulate neutrophil activation during Mg-deficiency (MgD). Male Sprague-Dawley rats (180g) were fed MgD (approximately 50 mg Mg/kg) or Mg-sufficient (MgS, 608 mg Mg/kg) diets for 7 days +/- NEP inhibitor phosphoramidon (PR, 5 mg/kg/day, s.c.). MgD alone induced a 9-fold (vs. MgS, p <0.01) elevation in plasma SP; MgD+PR enhanced it further to 18-fold (p <0.001). Neutrophils from MgD+PR rats displayed a 3.9-fold higher (p <0.01) basal .O(2-) generation, but those from MgD or PR alone were not activated. Plasma PGE2-metabolite levels rose 2.67- (p <0.01) and 1.56- (p <0.05) fold, respectively, in MgD+PR and MgD groups; the corresponding red blood cell glutathione levels were decreased 21% (p <0.025) and 7% (NS). MgD+PR significantly reduced neutrophil NEP activity by 48% (p <0.02); PR or MgD alone only reduced this activity 26% and 15%, respectively. We conclude that NEP inhibition potentiates SP-mediated neutrophil .O(2-) production and may promote other inflammatory activities during MgD.

Intestinal inflammation caused by magnesium deficiency alters basal and oxidative stress-induced intestinal function

The aim of this study was to determine the effect of magnesium deficiency on small intestinal morphology and function. Rats were assigned to 4 groups and placed on magnesium sufficient or deficient diet for 1 or 3 weeks. Infiltration of neutrophils and mucosal injury were assessed in stained sections of small intestine. Magnesium deficiency alone induced a significant increase in neutrophil infiltration and increased vascular ICAM-1 expression, in the absence of changes in mucosal injury or expression of proinflammatory mediators. Magnesium deficiency was associated with hyposecretory epithelial cell responses and vascular macromolecular leak in the small intestine and lung, which was attributed partly to reduced expression of NOS-3. To determine the effect of hypomagnesmia on the intestinal responses to a known oxidative stress, groups of rats were randomized to either sham operation or superior mesenteric artery occlusion for 10 (non-injurious) or 30 (injurious) minutes followed by a 1- or 4-hour reperfusion period. In response to mesenteric ischemia/reperfusion, deficient rats showed exaggerated PMN influx, but similar mucosal injury. Intestinal ischemia in sufficient animals induced vascular macromolecular leak in the small intestine and lung at 4 hours of reperfusion, with levels similar to those observed in untreated deficient rats. Acute magnesium repletion of deficient rats 24 h before surgery attenuated the exaggerated inflammation in deficient rats. These data show that magnesium deficiency induced a subclinical inflammation in the small intestine in the absence of mucosal injury, but with significant functional changes in local and remote organs and increased sensitivity to oxidative stress.

Magnesium intake and plasma concentrations of markers of systemic inflammation and endothelial dysfunction in women

BACKGROUND

Relations between magnesium intake and systemic inflammation and endothelial dysfunction are not well established.

OBJECTIVE

The aim of the present study was to examine whether and to what extent magnesium intake is related to inflammatory and endothelial markers.

DESIGN

We conducted a cross-sectional study of 657 women from the Nurses' Health Study cohort who were aged 43-69 y and free of cardiovascular disease, cancer, and diabetes mellitus when blood was drawn in 1989 and 1990. Plasma concentrations of C-reactive protein (CRP), interleukin 6 (IL-6), soluble tumor necrosis factor alpha receptor 2 (sTNF-R2), E-selectin, soluble intercellular adhesion molecule 1 (sICAM-1), and soluble vascular cell adhesion molecule 1 (sVCAM-1) were measured. Estimates from 2 semiquantitative food-frequency questionnaires, administered in 1986 and 1990, were averaged to assess dietary intakes.

RESULTS

In age-adjusted linear regression analyses, magnesium intake was inversely associated with plasma concentrations of CRP (P for linear trend = 0.003), E-selectin (P = 0.001), and sICAM-1 (P = 0.03). After further adjustment for physical activity, smoking status, alcohol use, postmenopausal hormone use, and body mass index, dietary magnesium intake remained inversely associated with CRP and E-selectin. Multivariate-adjusted geometric means for women in the highest quintile of dietary magnesium intake were 24% lower for CRP (1.70 +/- 0.18 compared with 1.30 +/- 0.10 mg/dL; P for trend = 0.03) and 14% lower for E-selectin (48.5 +/- 1.84 compared with 41.9 +/- 1.58 ng/mL; P for trend = 0.01) than those for women in the lowest quintile.

CONCLUSION

Magnesium intake from diet is modestly and inversely associated with some but not all markers of systematic inflammation and endothelial dysfunction in apparently healthy women.

Spironolactone Reduced Arrhythmia and Maintained Magnesium Homeostasis in Patients With Congestive Heart Failure

BACKGROUND

Patients with congestive heart failure (CHF) often have increased aldosterone activity that leads to hypomagnesemia. Hypomagnesemia can induce arrhythmias, an important cause of death in patients with CHF. We determined whether the aldosterone receptor antagonist spironolactone improved magnesium homeostasis and reduced arrhythmias in patients with CHF.

METHODS AND RESULTS

We randomized 116 consecutive patients with CHF into placebo control group (n = 58) and spironolactone group (20 mg daily, n = 58) in addition to conventional therapy. Plasma magnesium concentration (PMC), erythrocyte magnesium concentration (EMC), and erythrocyte magnesium efflux were not different between the 2 groups of patients before treatment. Compared with control patients, patients treated with spironolactone for 6 months had increased PMC and EMC and decreased erythrocyte magnesium efflux. Patients on spironolactone therapy also had a marked decrease of 24-hour mean heart rate, ventricular and atrial premature beats, and the risk of atrial fibrillation/flutter. Pooled data from the 116 patients showed that patients with a higher EMC or a lower sodium-dependent erythrocyte magnesium efflux had a slower heart rate, fewer ventricular premature beats, and a lower risk of atrial fibrillation/flutter.

CONCLUSIONS

Our results suggest that reducing cellular magnesium efflux and loss may contribute to the spironolactone-reduced arrhythmias in patients with CHF.

Substance P in traumatic brain injury

Recent evidence has suggested that neuropeptides, and in particular substance P (SP), may play a critical role in the development of morphological injury and functional deficits following acute insults to the brain. Few studies, however, have examined the role of SP, and more generally, neurogenic inflammation, in the pathophysiology of traumatic brain injury and stroke. Those studies that have been reported suggest that SP is released following injury to the CNS and facilitates the increased permeability of the blood brain barrier, the development of vasogenic edema and the subsequent cell death and functional deficits that are associated with these events. Inhibition of the SP activity, either through inhibition of the neuropeptide release or the use of SP receptor antagonists, have consistently resulted in profound decreases in edema formation and marked improvements in functional outcome. The current review summarizes the role of SP in acute brain injury, focussing on its properties as a neurotransmitter and the potential for SP to adversely affect outcome.

Magnesium deficiency augments myocardial response to reactive oxygen species

Magnesium (Mg) deficiency and oxidative stress are independently implicated in the etiopathogenesis of various cardiovascular disorders. This study was undertaken to examine the hypothesis that Mg deficiency augments the myocardial response to oxidative stress. Electrically stimulated rat papillary muscle was used for recording the contractile variation. Biochemical variables of energy metabolism (adenosine triphosphate (ATP) and creatine phosphate) and markers of tissue injury (lactate dehydrogenase (LDH) release and lipidperoxidation), which can affect myocardial contractility, were assayed in Langendorff-perfused rat hearts. Hydrogen peroxide (100 micromol/L) was used as the source of reactive oxygen species. The negative inotropic response to H2O2 was significantly higher in Mg deficiency (0.48 mmol Mg/L) than in Mg sufficiency (1.2 mmol Mg/L). Low Mg levels did not affect ATP levels or tissue lipid peroxidation. However, H2O2 induced a decrease in ATP; enhanced lipid peroxidation and the release of LDH were augmented by Mg deficiency. Increased lipid peroxidation associated with a decrease in available energy might be responsible for the augmentation of the negative inotropic response to H2O2 in Mg deficiency. The observations from this study validate the hypothesis that myocardial response to oxidative stress is augmented by Mg deficiency. This observation has significance in ischemia-reperfusion injury, where Mg deficiency can have an additive effect on the debilitating consequences.

Hypomagnesemia, oxidative stress, inflammation, and metabolic syndrome

BACKGROUND

Although hypomagnesemia, oxidative stress, and inflammation are involved in the pathogenesis of cardiovascular diseases, there is not a previous description concerning their potential interaction; thus, the aim of this study was to examine the relationship between metabolic syndrome (MetS), hypomagnesemia, inflammation, and oxidative stress.

METHODS

Case-control design study. Incident cases of MetS (84 women and 63 men) were compared with healthy control subjects (163 women and 131 men) matched by age and gender. MetS was diagnosed according to the Adult Treatment Panel III (ATP III) criterion. Oxidative stress was defined by serum malondialdehyde concentration (MDA) > or =50 mg/dL, low-grade chronic inflammation by C-reactive protein (CRP) serum levels > or =3 mg/L, and hypomagnesemia by serum magnesium concentrations < or =1.8 mg/dL.

RESULTS

Multivariate analysis adjusted by age, sex, body mass index, waist-to-hip ratio, and total adiposity showed a strong association between MetS and hypomagnesemia (OR 1.9; 95% CI 1.3-7.1), inflammation (OR 1.7; 95% CI 1.4-8.4), and oxidative stress (OR 1.4; 95% CI 0.9-12.6). Additional adjustment by CRP levels showed that MetS remained associated to hypomagnesemia (OR 1.4; 95% CI 1.1-5.9) but not to oxidative stress (OR 1.1; 95% CI 0.9-5.9), and adjusted by MDA levels, MetS remained strongly associated to hypomagnesemia (1.6; CI 95% 1.1-7.4), but not to inflammation (OR 1.05; 95% CI 0.97-14.2). Adjusted by serum magnesium levels, inflammation (OR 1.2; 95% CI 1.1-9.1) and oxidative stress (OR 1.1; 95% CI 1.1-9.7) were slightly associated to MetS.

CONCLUSIONS

The interaction of inflammation and oxidative stress is related and increases the risk for MetS, whereas serum magnesium levels and MetS are independently associated.

Magnesium and muscle performance in older persons: the InCHIANTI study

BACKGROUND

The role of magnesium in maintaining muscle integrity and function in older adults is largely unknown.

OBJECTIVE

We aimed to investigate the relation between serum magnesium concentrations and muscle performance in older subjects.

DESIGN

Data are from the baseline examination conducted between September 1998 and March 2000 of the InCHIANTI (aging in the Chianti area) study, a prospective epidemiologic survey of risk factors for late-life disability. From among 1453 randomly selected community residents completing a home interview, 1138 men (46%) and women (aged 66.7 +/- 15.2 y; x +/- SD) with complete data on muscle performance and serum magnesium who were not severely cognitively compromised and had no evidence of kidney disease or hypercalcemia were included in the analysis. Muscle performance was evaluated by grip strength, lower-leg muscle power, knee extension torque, and ankle extension isometric strength and was normalized for age and body mass index (BMI) within each sex.

RESULTS

After adjustment for age, sex, BMI, laboratory variables, presence of chronic diseases, muscle area, muscle density, and physical activity level, serum magnesium concentrations were significantly associated with indexes of muscle performance, including grip strength (beta = 2.0 +/- 0.5, P = 0.0002), lower-leg muscle power (beta = 8.8 +/- 2.7, P = 0.001), knee extension torque (beta = 31.2 +/- 7.9, P < 0.0001), and ankle extension strength (beta = 3.8 +/- 0.5, P < 0.0001).

CONCLUSIONS

The serum magnesium concentration is an independent correlate of muscle performance in older persons. Whether magnesium supplementation improves muscle function remains to be shown.

Neuroprotection in brain and spinal cord trauma

PURPOSE OF REVIEW

Traumatic brain and spinal cord injuries continue to be a public health problem. These types of injuries often occur in early adulthood and have a major impact for society. This review discusses strategies and therapeutic agents for perioperative neuroprotection in the management of brain and spinal cord trauma.

RECENT FINDINGS

There are no definitive drugs or strategies that can be utilized to provide perioperative neuroprotection in brain and spinal cord trauma patients. Phase III trials of several pharmacologic agents, including inhibitors of oxidative and excitotoxic injury, have been unable to demonstrate clinical efficacy. Although experimental animal data for hypothermia have been promising over the years, clinical application of therapeutic hypothermia cannot be recommended for routine use in neurotrauma patients. Administration of methylprednisolone, which has become common practice in acute spinal cord injury, has come under close scrutiny. Various experimental animal investigations suggest that potential therapeutic agents include estrogen, progesterone, minocycline, erythropoietin, and magnesium.

SUMMARY

The main priority in the initial treatment of brain and spinal cord trauma is to maintain oxygenation and perfusion in order to avoid aggravating secondary injury. Future progress will depend on the translation of neuroprotective strategies into well designed clinical trials with promising outcomes.

The nerve-heart connection in the pro-oxidant response to Mg-deficiency

Magnesium is a micronutrient essential for the normal functioning of the cardiovascular system, and Mg deficiency (MgD) is frequently associated in the clinical setting with chronic pathologies such as CHF, diabetes, hypertension, and other pathologies. Animal models of MgD have demonstrated a systemic pro-inflammatory/pro-oxidant state, involving multiple tissues/organs including neuronal, hematopoietic, cardiovascular, and gastrointestinal systems; during later stages of MgD, a cardiomyopathy develops which may result from a cascade of inflammatory events. In rodent models of dietary MgD, a significant rise in circulating levels of proinflammatory neuropeptides such as substance P (SP) and calcitonin gene-related peptide among others, was observed within days (1-7) of initiating the Mg-restricted diet, and implicated a neurogenic trigger for the subsequent inflammatory events; this early "neurogenic inflammation" phase may be mediated in part, by the Mg-gated N: -methyl-D-aspartate (NMDA) receptor/channel complex. Deregulation of the NMDA receptor may trigger the abrupt release of neuronal SP from the sensory-motor C-fibers to promote the subsequent pro-inflammatory changes: elevations in circulating inflammatory cells, inflammatory cytokines, histamine, and PGE(2) levels, as well as formation of nitric oxide, reactive oxygen species, lipid peroxidation products, and depletion of key endogenous antioxidants. Concurrent elevations of tissue CD14, a high affinity receptor for lipopolyssacharide, suggest that intestinal permeability may be compromised leading to endotoxemia. If exposure to these early (1-3 weeks MgD) inflammatory/pro-oxidant events becomes prolonged, this might lead to impaired cardiac function, and when co-existing with other pathologies, may enhance the risk of developing chronic heart failure.

Metabolic and immunologic derangements in cardiac cachexia: where to from here?

The onset of cardiac cachexia is characterized by a defined severe weight loss in patients with advanced chronic heart failure and it predicts an increased mortality in these patients. Recent studies with potential therapeutics investigated the effects and efficiency of beta-blockers, ghrelin, or ghrelin-agonists in cachexia. These and other new studies, like the influence of heart transplantation on cardiac cachexia, give prospect into potential therapeutic options in the future. General aim of the treatment strategy is to prevent the onset and retard the progress of cachexia. This could be achieved by modifying the metabolic, neurohormonal and immune system abnormalities, e.g. with beta-blockers and angiotensin-converting enzyme inhibitors. However, these alterations interact in a complex pathophysiological process, which is supposed to end in a vicious circle and thereby the wasting process is further promoted. To interrupt this, an early start of therapy is important to decelerate the development of cardiac cachexia. Many further investigations are needed to find out more about the pathophysiological pathways, to confirm the previous results, and to evaluate new therapeutics.

Intestinal and cardiac inflammatory response shows enhanced endotoxin receptor (CD14) expression in magnesium deficiency

Substance P is elevated in plasma and in other tissues during Mg-deficiency, and was found localised to neuronal C-fibres of cardiac and intestinal tissues, where it could promote neurogenic inflammation. Plasma prostaglandin E2 (PGE2), indicative of systemic inflammation, rose significantly (>or=4 fold, p<0.01) after 1 week and remained elevated through week 2 and 3 in rat on the Mg-deficient (MgD) diet. Concomitantly, total blood glutathione decreased by 50%. Immunohistochemical staining for endotoxin (lipopolysaccaride, LPS) receptor, CD14 was prominent in macrophage-type cells in intestinal tissue; more importantly, cardiac tissue revealed both CD11b (monocyte/macrophage surface protein) and CD14 positive cells after 3 weeks in rats on MgD diet. Western blot analysis indicated a significant increase in the endotoxin receptor protein level in the 3 week MgD hearts. Since CD14 is known to be up-regulated in cells exposed to LPS, these observations suggest that prolonged Mg-deficiency results in increased intestinal permeability to bacterial products that induce the endotoxin receptor in cells localized to myocardial and intestinal tissues. These CD14 positive cells may amplify the cardiomyopathic inflammatory process by stimulating TNF-alpha and other pro-inflammatory cytokines.

A functional biological marker is needed for diagnosing magnesium deficiency

Functional biological markers or biomarkers are now available for many nutrients which are used as nutritional status markers. Most sources of these biomarkers are products or precursors of enzymatic processes that can be measured in serum and plasma. At this time measurements of total or ionized magnesium (Mg) in serum, plasma, cellular components, urine or Mg retention from a load test are performed, but they may not always reflect Mg nutritional status. Biomarkers for Mg are needed which would reflect changes in biochemical processes where Mg is involved. Biomarkers for Mg need to be identified and evaluated in both animals and humans, with a determination of possible factors that may affect the reaction and biomarker concentrations. Some possible biomarkers for Mg include the following: Na/K ATPase, thromboxane B2, C-reactive protein, and endothelin-1. Other possible biomarkers for Mg need to be identified.