Low intracellular magnesium levels promote platelet-dependent thrombosis in patients with coronary artery disease

Thrombogenicity of biodegradable metals

Biodegradable metals offer a promising means to ameliorate many of the long-term risks associated with vascular devices made of conventional biostable stent metals. While numerous biodegradable metal alloys have been developed and characterized in animal models, knowledge of their blood reactivity and thrombogenicity remains unknown. Metal hemocompatibility is particularly valuable because current generation drug-eluting stents pose a significant long-term thrombosis risk. In this study, four pure metals, widely used as degradable base materials (Fe, Zn, Mg, and Mo), and three alloys commonly used in cardiovascular devices [NiTi, CoCr, and stainless steel (SS)] were evaluated. This work examined how each of these metals activate platelets, coagulation factors, and inflammation using in vitro hemocompatibility assays and a clinically relevant ex vivo non-human primate arteriovenous shunt model. Testing found that while all metals promoted a downstream activation of platelets and coagulation in flowing whole blood, platelet and fibrin attachment to Mg was markedly reduced. Additionally, Fe and Mo trended toward higher platelet attachment and contact pathway activation. Overall, the results suggest that Mg may delay clot initiation, but not eliminate clot formation, indicating the importance of understanding thrombosis in Mg alloys that are currently being developed for clinical use as biodegradable stents.

Association of Dietary Magnesium Intake with the Risk of Stroke among Adults

The relationship between dietary magnesium intake and the risk of stroke is controversial. This study aimed to examine the association of dietary magnesium intake with the risk of stroke among American adults.The relationship between dietary magnesium intake and the risk of stroke was analyzed using the National Health and Nutrition Examination Survey (NHANES) 2007-2018 data with 29,653 adults. The amount of magnesium from the diet was assessed by two 24-hour dietary recalls. Stroke outcomes were defined using the results of the self-reported questionnaires. The association between dietary magnesium intake and the risk of stroke was evaluated using logistic regression models and restricted cubic spline.In our study, an inverse association between dietary magnesium intake and the risk of stroke was found. For the highest versus lowest quartile of dietary magnesium intake, the multivariate-adjusted odds ratio (95% confidence interval) of stroke was 0.56 (0.36-0.86). The magnesium intake of women was negatively associated with stroke risk, but this negative association was not found in men. Then, the inverse association was statistically significant among the 40-59 year-old group. The results from the dose-response analysis show a linear relationship between dietary magnesium intake and the risk of stroke.Dietary magnesium intake was inversely associated with the risk of stroke, especially in women. Therefore, our study emphasizes the importance of appropriately increasing dietary magnesium intake.

Serum Magnesium Is Associated with Long-Term Survival of Non-ST-Elevation Myocardial Infarction Patients

BACKGROUND

Low serum magnesium (sMg) is associated with cardiovascular risk factors and atherosclerotic disease.

OBJECTIVE

To evaluate the association between sMg levels on admission and clinical outcomes in hospitalized non-ST-elevation myocardial infarction (NSTEMI) patients.

METHODS

A retrospective analysis of all patients admitted to a single tertiary center with a primary diagnosis of NSTEMI. Patients with advanced chronic kidney disease were excluded. Clinical data were collected and compared between lower sMg quartile patients (Q1; sMg < 1.9 mg/dL) and all other patients (Q2-Q4; sMg ≥ 1.9 mg/dL).

RESULTS

The study cohort included 4552 patients (70% male, median age 69 [IQR 59-79]) who were followed for a median of 4.4 (IQR 2.4-6.6) years. The median sMg level in the low sMg group was 1.7 (1.6-1.8) and 2.0 (2.0-2.2) mg/dL in the normal/high sMg group. The low sMg group was older (mean of 72 vs. 67 years), less likely to be male (64% vs. 72%), and had higher rates of comorbidities, including diabetes, hypertension, and atrial fibrillation (59% vs. 29%, 92% vs. 85%, and 6% vs. 5%; p < 0.05 for all). Kaplan-Meier survival analysis demonstrated significantly higher cumulative death probability at 4 years in the low sMg group (34% vs. 22%; p log rank <0.001). In a multivariable analysis model adjusted for sex, significant comorbidities, coronary interventions during the hospitalization, and renal function, the low sMg group exhibited an independent 24% increased risk of death during follow up (95% CI 1.11-1.39; p < 0.001).

CONCLUSIONS

Low sMg is independently associated with higher risk of long-term mortality among patients recovering from an NSTEMI event.

The Significance of Low Magnesium Levels in COVID-19 Patients

Magnesium is the fourth most common mineral in the human body and the second richest intracellular cation. This element is necessary for many physiological reactions, especially in the cardiovascular and respiratory systems. COVID-19 is an infectious disease caused by SARS-CoV-2. The majority of people who become ill as a result of COVID-19 have mild-to-moderate symptoms and recover without specific treatment. Moreover, there are people who develop severe forms of COVID-19, which require highly specialized medical assistance. Magnesium deficiency may play a role in the pathophysiology of infection with SARS-CoV-2. The primary manifestation of COVID-19 remains respiratory, but the virus can spread to other organs and tissues, complicating the clinical picture and culminating in multiorgan failure. The key mechanisms involved in the disease include direct viral cytotoxicity, endothelial dysfunction, and exaggerated release of inflammatory cytokines. The aim of this review was to summarize the available data regarding the role of magnesium in COVID-19 patients and its particularities in different clinical settings.

Low serum magnesium is associated with poor functional outcome in acute ischemic stroke or transient ischemic attack patients

AIM

The association between magnesium and outcomes after stroke is uncertain. We aimed to investigate the association of serum magnesium with all-cause mortality and poor functional outcome.

METHODS

We included patients with acute ischemic stroke (AIS) or transient ischemic attack (TIA) from the China National Stroke Registry III. We used Cox proportional hazards model for all-cause mortality and logistic regression model for poor functional outcome (modified Rankin Scale [mRS] 2-6/3-6) to examine the relationships.

RESULTS

Among the 6483 patients, the median (interquartile range) magnesium was 0.87 (0.80-0.93) mmol/L. Patients in the first quartile had a higher risk of mRS score 3-6/2-6 at 3 months (adjusted odds ratio [OR]: 1.30; 95% confidence interval [CI]: 1.02, 1.64; adjusted OR: 1.29; 95% CI: 1.04-1.59) compared with those in the fourth quartile. Similar results were found for mRS score 26 at 1 year. The age- and sex-adjusted hazard ratio (HR) with 95% CI in first quartile magnesium was 1.40 (1.02-1.93) for all-cause mortality within 1 year, but became insignificant (HR: 1.03; 95% CI: 0.71-1.50) after adjusting for potential variables.

CONCLUSIONS

Low serum magnesium was associated with a high risk of poor functional outcome in patients with AIS or TIA.

The Association between Dietary Magnesium Intake and Telomere Length in Adults with Hypertension

BACKGROUND

Dietary micronutrients are significantly associated with telomere length, as shown in multiple studies. However, no study has investigated the association between magnesium intake and telomere length in adults with hypertension.

METHODS

Participants were included from the National Health and Nutrition Examination Survey (NHANES) in 1999-2000 and 2001-2002. Dietary magnesium intake was assessed using the 24 - hour recall method and the telomere length of leukocytes was measured using polymerase chain reaction (PCR). A multivariate regression model was then used to assess the association between dietary magnesium intake and telomere length in adults with hypertension.

RESULTS

Our final analysis included 2199 hypertensive adults (46.79% males) with a mean dietary magnesium intake of 254.82±133.47 mg/day. Linear regression, adjusted for race, sex, age, smoking, uric acid, and other variables, showed that every 1 mg increase in dietary magnesium intake was associated with a 0.20 (95% CI: 0.01, 0.39, p = 0.043) longer telomere length in all participants. In the ≥45 years age group, there was a statistically significant association between the telomere length and dietary magnesium (95% CI: 0.16, 0.63, p <0.001).

CONCLUSIONS

This study suggests that increased magnesium intake is associated with a longer telomere length in hypertensive adults, especially in those ≥45 years of age. However, further research is needed to determine a causal relationship.

Associations of Serum Magnesium with Brain Morphology and Subclinical Cerebrovascular Disease: The Atherosclerosis Risk in Communities-Neurocognitive Study

Circulating magnesium has been associated with a lower risk of dementia, but the physiologic effects by which magnesium may prevent neurological insults remain unclear. We studied 1466 individuals (mean age 76.2 ± 5.3, 28.8% black, 60.1% female) free of prevalent stroke, with measured serum magnesium and with available MRI scans obtained in 2011–2013, participating in the Atherosclerosis Risk in Communities Neurocognitive Study (ARIC-NCS). Cross-sectional differences in frontal, temporal, parietal, and occipital lobe volume, along with deep grey matter, total brain, and white matter hyperintensity volume across serum magnesium (categorized into quintiles and per standard deviation increases) were assessed using multiple linear regression. We also examined associations of magnesium with the prevalence of cortical, subcortical, and lacunar infarcts using multiple logistic regression. After adjusting for demographics, biomarkers, medications, and cardiometabolic risk factors, higher circulating magnesium was associated with greater total brain volume and frontal, temporal, and parietal lobe volumes (volumes 0.14 to 0.19 standard deviations higher comparing Q5 to Q1). Elevated magnesium was also associated with lower odds of subcortical infarcts (OR (95%CI): 0.44 (0.25, 0.77) comparing Q5 to Q1) and lacunar infarcts (OR (95%CI): 0.40 (0.22, 0.71) comparing Q5 to Q1). Elevated serum magnesium was cross-sectionally associated with greater brain volumes and lower odds of subclinical cerebrovascular disease, suggesting beneficial effects on pathways related to neurodegeneration and cerebrovascular damage. Further exploration through prospective analyses is needed to assess increasing circulating magnesium as a potential neuroprotective intervention.

A critical evaluation of caplacizumab for the treatment of acquired thrombotic thrombocytopenic purpura

Introduction: Acquired thrombotic thrombocytopenic purpura (aTTP) is a thrombotic microangiopathy caused by inhibitory autoantibodies against ADAMTS13 protein. Until recently, the combination of plasma exchange (PEX) and immunosuppression has been the standard front-line treatment in this disorder. However, aTTP-related mortality, refractoriness, and relapse are still a matter of concern. Areas covered: The better understanding of the pathophysiological mechanisms of aTTP has allowed substantial improvements in the diagnosis and treatment of this disease. Recently, the novel anti-VWF nanobody caplacizumab has been approved for acute episodes of aTTP. Caplacizumab is capable to block the adhesion of platelets to VWF, therefore inhibiting microthrombi formation in the ADAMTS13-deficient circulation. In this review, the characteristics of caplacizumab together with the available data of its efficacy and safety in the clinical setting will be analyzed. Besides, the current scenario of aTTP treatment will be provided, including the role of other innovative drugs. Expert opinion: With no doubt, caplacizumab is going to change the way we treat aTTP. In combination with standard treatment, caplacizumab can help to significantly reduce aTTP-related mortality and morbidity and could spare potential long-term consequences by minimizing the risk of exacerbation.

A Review of the Action of Magnesium on Several Processes Involved in the Modulation of Hematopoiesis

Magnesium (Mg²⁺) is an essential mineral for the functioning and maintenance of the body. Disturbances in Mg²⁺ intracellular homeostasis result in cell-membrane modification, an increase in oxidative stress, alteration in the proliferation mechanism, differentiation, and apoptosis. Mg²⁺ deficiency often results in inflammation, with activation of inflammatory pathways and increased production of proinflammatory cytokines by immune cells. Immune cells and others that make up the blood system are from hematopoietic tissue in the bone marrow. The hematopoietic tissue is a tissue with high indices of renovation, and Mg²⁺ has a pivotal role in the cell replication process, as well as DNA and RNA synthesis. However, the impact of the intra- and extracellular disturbance of Mg²⁺ homeostasis on the hematopoietic tissue is little explored. This review deals specifically with the physiological requirements of Mg²⁺ on hematopoiesis, showing various studies related to the physiological requirements and the effects of deficiency or excess of this mineral on the hematopoiesis regulation, as well as on the specific process of erythropoiesis, granulopoiesis, lymphopoiesis, and thrombopoiesis. The literature selected includes studies in vitro, in animal models, and in humans, giving details about the impact that alterations of Mg²⁺ homeostasis can have on hematopoietic cells and hematopoietic tissue.

Magnesium, Oxidative Stress, Inflammation, and Cardiovascular Disease

Hypomagnesemia is commonly observed in heart failure, diabetes mellitus, hypertension, and cardiovascular diseases. Low serum magnesium (Mg) is a predictor for cardiovascular and all-cause mortality and treating Mg deficiency may help prevent cardiovascular disease. In this review, we discuss the possible mechanisms by which Mg deficiency plays detrimental roles in cardiovascular diseases and review the results of clinical trials of Mg supplementation for heart failure, arrhythmias and other cardiovascular diseases.

Harnessing adenosine A2A receptors as a strategy for suppressing the lung inflammation and thrombotic complications of COVID-19: Potential of pentoxifylline and dipyridamole

Counterproductive lung inflammation and dysregulated thrombosis contribute importantly to the lethality of advanced COVID-19. Adenosine A2A receptors (A2AR), expressed by a wide range of immune cells, as well as endothelial cells and platelets, exert cAMP-mediated anti-inflammatory and anti-thrombotic effects that potentially could be highly protective in this regard. The venerable drug pentoxifylline (PTX) exerts both anti-inflammatory and antithrombotic effects that reflect its ability to boost the responsiveness of A2AR to extracellular adenosine. The platelet-stabilizing drug dipyridamole (DIP) blocks intracellular uptake of extracellularly-generated adenosine, thereby up-regulating A2AR signaling in a way that should be functionally complementary to the impact of PTX in that regard. Moreover, DIP has recently been reported to slow the cellular replication of SARS-CoV-2 in clinically feasible concentrations. Both PTX and DIP are reasonably safe, well-tolerated, widely available, and inexpensive drugs. When COVID-19 patients can be treated within several days of symptom onset, using PTX + DIP in conjunction with hydroxychloroquine (HCQ) and an antibiotic – azithromycin (AZM) or doxycycline – might be warranted. HCQ and AZM can suppress SARS-CoV-2 proliferation in vitro and may slow the cell-to-cell spread of the virus; a large case series evaluating this combination in early-stage patients reported an impressively low mortality rate. However, whereas HCQ and AZM can promote QT interval lengthening and may be contraindicated in more advanced COVID-19 entailing cardiac damage, doxycycline has no such effect and exerts a potentially beneficial anti-inflammatory action. In contrast to HCQ, we propose that the combination of PTX + DIP can be used in both early and advanced stages of COVID-19. Concurrent use of certain nutraceuticals – yeast beta-glucan, zinc, vitamin D, spirulina, phase 2 inducers, N-acetylcysteine, glucosamine, quercetin, and magnesium – might also improve therapeutic outcomes in COVID-19.

Are Circulating Mg2+ Levels Associated with Glucose Tolerance Profiles and Incident Type 2 Diabetes?

Magnesium (Mg²⁺) is an enzyme co-factor that plays a key role in many biochemical reactions, as well as in glucose metabolism. Clinical evidences have demonstrated that depletion of serum Mg²⁺ increases exponentially with the duration of type 2 diabetes mellitus (T2DM). Diabetes is associated with low Mg²⁺, and hypomagnesemia is associated with insulin resistance, inflammation, and increased risk for cardiovascular disease. In subjects at high risk of inflammation and insulin resistance, supplementation of Mg²⁺ alone ameliorates both phenotypes, slowing the development and progression of hepatic steatosis. We analyze the relationship between serum Mg²⁺ levels and the onset of T2DM in a large cohort of well-characterized adult white individuals participating in the CATAMERI study, who were reexamined after a mean follow-up of 5.6 ± 0.9 years. In our analysis we acquired a significant negative correlation between Mg²⁺ levels, fasting glucose, and 2h-post load glucose in subjects who underwent an OGTT. Moreover, Mg²⁺ levels correlated negatively with fasting insulin levels, and positively with the lipid profile. As for the detrimental effect of lower circulating Mg²⁺ levels, our data revealed a significant reduction of T2DM risk of about 20% for each 1 mg/dL increase of circulating Mg²⁺. The present results are consistent with the theory that Mg²⁺ supplementation could ameliorate insulin sensitivity reducing the risk to develop T2DM.

Reuniting overnutrition and undernutrition, macronutrients, and micronutrients

Over-nutrition and its late consequences are a dominant theme in medicine today. In addition to the health hazards brought on by over-nutrition, the medical community has recently accumulated a roster of health benefits with obesity, grouped under "obesity paradox." Throughout the world and throughout history until the 20^th century, under-nutrition was a dominant evolutionary force. Under-nutrition brings with it a mix of benefits and detriments that are opposite to and continuous with those of over-nutrition. This continuum yields J-shaped or U-shaped curves relating body mass index to mortality. The overweight have an elevated risk of dying in middle age of degenerative diseases while the underweight are at increased risk of premature death from infectious conditions. Micronutrient deficiencies, major concerns of nutritional science in the 20^th century, are being neglected. This "hidden hunger" is now surprisingly prevalent in all weight groups, even among the overweight. Because micronutrient replacement is safe, inexpensive, and predictably effective, it is now an exceptionally attractive target for therapy across the spectrum of weight and age. Nutrition-related conditions worthy of special attention from caregivers include excess vitamin A, excess vitamin D, and deficiency of magnesium.

The Association Between Proton Pump Inhibitor Use With Acute Kidney Injury and Chronic Kidney Disease

Proton pump inhibitors (PPIs) are among the most commonly prescribed medicines and are the mainstay of treatment for gastroesophageal reflux disease. Recently, there has been an increase in the use of these medicines for unclear and inappropriate indications. Although generally well tolerated and considered to be safe, several observational studies have linked PPI use with a variety of conditions such as pneumonia, Clostridium difficile infection, fractures, hypomagnesemia, and dementia. The well-established association between PPIs and acute interstitial nephritis has raised questions about whether they may also cause acute kidney injury and chronic kidney disease. Observational studies have evaluated these possible associations. This paper reviews the currently available literature about these associations and considers their possible underlying pathophysiological mechanisms. The level of evidence-linking PPI use with acute kidney injury and chronic kidney disease is weak and does not establish causality. More research is required to explore these possible associations further. The PPIs should be used in the lowest effective dose and inappropriate use should be avoided.

Subclinical magnesium deficiency: a principal driver of cardiovascular disease and a public health crisis

Because serum magnesium does not reflect intracellular magnesium, the latter making up more than 99% of total body magnesium, most cases of magnesium deficiency are undiagnosed. Furthermore, because of chronic diseases, medications, decreases in food crop magnesium contents, and the availability of refined and processed foods, the vast majority of people in modern societies are at risk for magnesium deficiency. Certain individuals will need to supplement with magnesium in order to prevent suboptimal magnesium deficiency, especially if trying to obtain an optimal magnesium status to prevent chronic disease. Subclinical magnesium deficiency increases the risk of numerous types of cardiovascular disease, costs nations around the world an incalculable amount of healthcare costs and suffering, and should be considered a public health crisis. That an easy, cost-effective strategy exists to prevent and treat subclinical magnesium deficiency should provide an urgent call to action.

Review of epidemiological studies on drinking water hardness and cardiovascular diseases

BACKGROUND

Major risk factors do not entirely explain the worldwide variability of morbidity and mortality due to cardiovascular disease. Environmental exposures, including drinking water minerals may affect cardiovascular disease risks.

METHOD

We conducted a qualitative review of the epidemiological studies of cardiovascular disease and drinking water hardness and calcium and magnesium levels.

RESULTS

Many but not all ecological studies found an inverse (i.e., protective) association between cardiovascular disease mortality and water hardness, calcium, or magnesium levels; but results are not consistent. Some case-control studies and one cohort study found either a reduced cardiovascular disease mortality risk with increased drinking water magnesium levels or an increased risk with low magnesium levels. However, the analytical studies provide little evidence that cardiovascular risks are associated with drinking water hardness or calcium levels.

CONCLUSION

Information from epidemiological and other studies supports the hypothesis that a low intake of magnesium may increase the risk of dying from, and possibly developing, cardiovascular disease or stroke. Thus, not removing magnesium from drinking water, or in certain situations increasing the magnesium intake from water, may be beneficial, especially for populations with an insufficient dietary intake of the mineral.

Low magnesium is not a significant predictor of hard events in acute myocardial infarction

Background

Although magnesium (Mg) has recognized cardioprotective properties and hypomagnesemia is common in patients with acute myocardial infarction (AMI), data regarding the role of Mg as prognostic factor for adverse events are scarce, as well as there are conflicting results on the use of Mg as adjuvant therapy in AMI.

Aim

To evaluate the role of Mg as predictor for hard events (HE, all cause death, and nonfatal myocardial infarction) in AMI patients.

Design and patients

We studied 406 AMI patients (306 males, age: 67 ± 12 years, mean ± SD). Patient data were collected from the Institute electronic databank which saves demographic, clinical, instrumental, therapeutical and follow-up data of all patients admitted to our Coronary Unit.

Results

During a mean follow-up period of 21 ± 18 months, the combined endpoint accounted for 63 HE, 44 (11%) deaths (35 cardiac deaths), 19 (5%) nonfatal MI.

The multiple regression model identified glycemia as the only independent determinant of Mg in AMI pts. (T value = − 2.8, standard coefficient = − 0.15, p < 0.01). The Kaplan–Meier survival estimates failed to show a significantly worst outcome in patients presenting low Mg (< 0.783 mmol/L, 25th percentile). Aging (> 67 years—50th percentile), and ejection fraction (< 40%) remained as prognostic factors for HE in the adjusted Cox multivariate proportional hazard model (HR = 2.8, 95% CI = 1.6–5, p < 0.001; HR = 3.2, 95% CI = 1.9–5.3 p < 0.001, respectively).

Conclusion

The present findings do not support a significant role of low Mg as predictor for HE in AMI.

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It has been hypothesized that Mg may play a key role in ischemic heart disease.

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Mg role as predictor for HE-death, nonfatal myocardial infarction-in AMI was studied.

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Our results do not give support for a role of hypomagnesia as HE predictor in AMI.

Nutritional factors in the prevention and management of coronary artery disease and heart failure

Nutritional factors such as magnesium, folic acid, vitamins B12 and B6, L-arginine, and polyunsaturated fatty acids (PUFAs) appear to be significantly beneficial for patients with coronary artery disease (CAD), and in the prevention and arresting the progression of HF and cardiac arrhythmias. Additionally, ingestion of adequate amounts of protein and maintaining normal concentrations of plasma albumin seem to be essential for these patients. These nutrients closely interact with the metabolism of L-arginine-nitric oxide (NO) system, essential fatty acids, and eicosanoids such that beneficial products such as NO, prostaglandin E1, prostacyclin, prostaglandin I3, lipoxins, resolvins, and protectins are generated and synthesis of proinflammatory cytokines is suppressed that results in platelet anti-aggregation, vasodilation, angiogenesis, and prevention of CAD, cardiac arrhythmias, and stabilization of HF. This implies that individuals at high risk for CAD, cardiac arrhythmias, and HF and those who have these diseases need to be screened for plasma levels of magnesium, folic acid, vitamins B12 and B6, L-arginine, NO, various PUFAs, lipoxin A4, resolvins, protectins, asymmetrical dimethylarginine (an endogenous inhibitor of NO), albumin, and various eicosanoids and cytokines and correct their abnormalities to restore normal physiology.

Association between low serum magnesium level and major adverse cardiac events in patients treated with drug-eluting stents for acute myocardial infarction

Objectives

We investigated the association of serum magnesium (Mg) levels and major adverse cardiac events (MACEs) after drug-eluting stent (DES) implantation.

Background

Mg depletion plays a key role in the pathphysiologic features of diabetes mellitus, hypertension, thrombosis, arrhythmias and coronary artery disease. Whether the depletion is related to the long-term prognosis of DES implantation is not known.

Methods

From 2008 to 2011, we enrolled 414 consecutive patients <50 years old who underwent DES implantation for acute coronary syndrome. Serum Mg level was analyzed and patients were followed up for a median of 24 months (interquartile range 14–32 months) for the occurrence of MACEs defined as death, myocardial infarction, stroke, and any revascularization.

Results

For patients with unstable angina, no significant association between serum Mg level and MACEs was found in the multivariate model. For patients with myocardial infarction, after adjusting for age, positive family history, smoking status, hypertension, hypercholesterolemia, and diabetes at baseline, the risk was 8.11-fold higher for patients with quartile 1 than 4 Mg level (95% confidence interval 1.7–38.75; P<0.01). In addition, when tested as a continuous variable, serum magnesium was a significant predictor for MACEs of acute myocardial infarction (HR [per 0.1 mM increase], 0.35 [95% CI, 0.19–0.63], p< 0.01), after adjustment for other confounders.

Conclusions

Low serum level of Mg may be an important predictor of MACEs with DES implantation for acute myocardial infarction. Further research into the effectiveness of Mg supplementation for these patients is warranted.

Deep sea water prevents balloon angioplasty-induced hyperplasia through MMP-2: an in vitro and in vivo study

Major facts about the development of restenosis include vascular smooth muscle cells (VSMCs) proliferation and migration. A previous study showed that in vitro treatment with magnesium chloride has the potential to affect the proliferation and migration of VSMCs. Magnesium is the major element in deep sea water (DSW) and is a biologically active mineral. It is unclear whether DSW intake can prevent abnormal proliferation and migration of VSMCs as well as balloon angioplasty-induced neointimal hyperplasia. Thus, we attempted to evaluate the anti-restenotic effects of DSW and its possible molecular mechanisms. Several concentrations of DSW, based on the dietary recommendations (RDA) for magnesium, were applied to a model of balloon angioplasty in SD rats. The results showed that DSW intake markedly increased magnesium content within the vascular wall and reduced the development of neointimal hyperplasia. The immunohistochemical analysis also showed that the expression of proteins associated with cell proliferation and migration were decreased in the balloon angioplasty groups with DSW supplement. Furthermore, in vitro treatment with DSW has a dose-dependent inhibitory effect on serum-stimulated proliferation and migration of VSMCs, whose effects might be mediated by modulation of mitogen-activated protein kinase (MAPK) signaling and of the activity of matrix metalloproteinase-2 (MMP-2). Our study suggested that DSW intake can help prevent neointimal hyperplasia (or restenosis), whose effects may be partially regulated by magnesium and other minerals.

Relationship of serum magnesium concentration to risk of short-term outcome of acute ischemic stroke

OBJECTIVE

To assess whether serum magnesium concentration can predict risk of short-term outcome of acute ischemic stroke.

METHODS

Between January 1, 2006 and December 31, 2008, 1493 patients with acute ischemic stroke were recruited from four hospitals in Shandong province, P.R China. Data on demographic characteristics, life style risk factors, history of cardiovascular disease, admission blood pressure and other clinical characteristics were collected from all subjects. The short-term outcome was defined as neurological deficiency NIHSS ≥ 10 or death (NIHSS ≥ 10/death). The Cox proportion hazard regression model was used to evaluate the association between serum magnesium concentration and risk of short-term outcome of acute ischemic stroke.

RESULTS

Serum magnesium concentration in subjects with NIHSS ≥ 10/death was lower than those with NIHSS < 10 (p < 0.05). When comparing the highest quartile of serum magnesium concentration with the lowest quartile in an unadjusted model, there was a decreased risk of NIHSS ≥ 10/death in individuals with the highest quartile; the risk ratio (RR) was 0.47 (p < 0.05). However, after adjustment for age, sex, serum calcium concentration, serum potassium concentration and other covariates, the fourth and the third quartiles of serum magnesium concentration were associated with decreased risks of NIHSS ≥ 10/death; the RRs were 0.40 and 0.56 (all p < 0.05), respectively. The dose-response relationship between serum magnesium concentration and risk of NIHSS ≥ 10/death was not materially altered after adjustment for other covariates (p-value for trend = 0.002).

CONCLUSION

Higher serum magnesium concentration was associated with lower risk of NIHSS ≥ 10/death; there was a dose-response relationship between serum magnesium concentration and risk of NIHSS ≥ 10/death.

Thrombotic microangiopathy: a role for magnesium?

Despite advances in more recent years, the pathophysiology and especially treatment modalities of thrombotic microangiopathy (TMA) largely remain enigmatic. Disruption of endothelial homeostasis plays an essential role in TMA. Considering the proven causal association between magnesium and both endothelial function and platelet aggregability, we speculate that a magnesium deficit could influence the course of TMA and the related haemolytic uraemic syndrome and thrombotic thrombocytopenic purpura. A predisposition towards TMA is seen in many conditions with both extracellular and intracellular magnesium deficiency. We propose a rationale for magnesium supplementation in TMA, in analogy with its evidence-based therapeutic application in pre-eclampsia and suggest, based on theoretical grounds, that it might attenuate the development of TMA, minimise its severity and prevent its recurrence. This is based on several lines of evidence from both in vitro and in vivo data showing dose-dependent effects of magnesium supplementation on nitric oxide production, platelet aggregability and inflammation. Our hypothesis, which is further amenable to assessment in animal models before therapeutic applications in humans are implemented, could be explored both in vitro and in vivo to decipher the potential role of magnesium deficit in TMA and of the effects of its supplementation.

Rizatriptan benzoate influences the endogenous pain modulatory system in a rat model of migraine

The present study utilized a nitroglycerin-induced rat model of migraine to detect the effects of rizatriptan benzoate on proenkephalin and substance P gene expression in the midbrain using real-time quantitative polymerase chain reaction and investigate whether rizatriptan benzoate can regulate the endogenous pain modulatory system. The results showed that rizatriptan benzoate significantly reduced expression of the mRNAs for proenkephalin and substance P. Rizatriptan benzoate may inhibit the analgesic effect of the endogenous pain modulatory system.

Platelet additive solution - electrolytes

Recent attention to solutions that replace most or all plasma in platelet concentrates, while maintaining satisfactory platelet function, is motivated by the potential of plasma reduction or depletion to mitigate various transfusion-related adverse events. This report considers the electrolytic composition of previously described platelet additive solutions, in order to draw general conclusions about what is required for platelet function and longevity. The optimal concentrations of Na(+) and Cl(-) are 69-115 mM. The presence of both K(+) and Mg(2+) in platelet suspension at nearly physiological concentrations (3-5mM and 1.5-3mM, respectively) is indispensable for good preservation capacity because both electrolytes are required to prevent platelet activation. In contrast to K(+) and Mg(2+), Ca(2+) may not be important because no free Ca(2+) is available in M-sol, which showed excellent platelet preservation capacity at less than 5% plasma concentration. The importance of bicarbonate (approximately 40 mM) can be recognized when the platelets are suspended in additive solution under less than 5% residual plasma concentration.

Temporal changes in circulating P-selectin, plasminogen activator inhibitor-1, magnesium, and creatine kinase after percutaneous coronary intervention

OBJECTIVE

This study aims to determine the mechanisms underlying restenosis and ischemia-reperfusion injury of the myocardium after percutaneous coronary intervention (PCI).

METHODS

The present study examined serial changes (5 min, 30 min, 2 h, 6 h, and 24 h after PCI) in circulating P-selectin, plasminogen activator inhibitor-1 (PAI-1), magnesium (Mg), and creatine kinase-myocardial band fraction (CK-MB) levels, which may be associated with restenosis and myocardial injury in patients undergoing PCI. The occurrence rates of major adverse cardiovascular events were collected over a six-month follow-up.

RESULTS

PCI induced an early elevation of P-selectin, which correlated positively with the inflation pressure used in the PCI procedure. PCI also caused a significant and sustained decrease in serum Mg in PCI patients, without an effect on PAI-1. An increase in CK-MB was observed in PCI patients, although values were within normal reference range. In addition, elevated P-selectin and decreased Mg measured shortly after the coronary angioplasty procedure were associated with recurrent treatment and heart failure, respectively.

CONCLUSIONS

Our study demonstrates that PCI induces temporal changes of P-selectin, Mg, and CK-MB, which may be involved in restenosis and ischemia-reperfusion injury. These findings highlight the need for using antiplatelet therapy and Mg to reduce the risks associated with PCI.

Intracellular magnesium of obese and type 2 diabetes mellitus children

INTRODUCTION

Magnesium is a critical cofactor in numerous enzymatic reactions. Diabetic patients and obese subjects are often reported to have intracellular magnesium ([Mg(2+)](i)) deficiency. We studied the change of [Mg(2+)](i) in obese children and children with type 2 diabetes mellitus (DM2) after educational intervention or treatment.

METHODS

A total of 25 subjects were included: 13 with simple obesity (10 male, 3 female; mean age 16±8 years, intervention period 1.0±0.6 years), 12 with DM2 (8 male, 4 female; mean age 15±3 years, medication period 1.1±0.7 years), and 16 controls (8 male, 8 female; mean age 17±7 years). By using a fluorescent probe, mag-fura-2, we examined the basal and insulin-stimulated [Mg(2+)](i) of platelets in the blood. Plasma leptin, ghrelin, adiponectin, and resistin levels were determined with the use of enzyme-linked immunosorbent assay (ELISA).

RESULTS

Mean basal [Mg(2+)](i) was lower in the obesity (160±65 μmol/L) and DM2 groups (140±30 μmol/L) compared with the control group (330±28 μmol/L). The elevated [Mg(2+)](i) after insulin stimulation was also lower in these two groups (420±140 μmol/L, and 330±70 μmol/L, respectively) compared with the control group (690±270 μmol/L). In the DM2 group, the basal [Mg(2+)](i) was significantly increased after treatment, while in the obesity group, stimulated [Mg(2+)](i) was increased after intervention.

CONCLUSION

Platelet [Mg(2+)](i) increased after intervention in children with obesity or DM2.

Serum and dietary magnesium and risk of ischemic stroke: the Atherosclerosis Risk in Communities Study

The authors sought to examine the relation between serum or dietary magnesium and the incidence of ischemic stroke among blacks and whites. Between 1987 and 1989, 14,221 men and women aged 45-64 years took part in the first examination of the Atherosclerosis Risk in Communities Study cohort. The incidence of stroke was ascertained from hospital records. Higher serum magnesium levels were associated with lower prevalence of hypertension and diabetes mellitus at baseline. During the 15-year follow-up, 577 ischemic strokes occurred. Serum magnesium was inversely associated with ischemic stroke incidence. The age-, sex-, and race-adjusted rate ratios of ischemic stroke for those with serum magnesium levels of <or=1.5, 1.6, 1.7, and >or=1.8 mEq/L were 1.0, 0.78 (95% confidence interval (CI): 0.62, 0.96), 0.70 (95% CI: 0.56, 0.88), and 0.75 (95% CI: 0.59, 0.95) (P(trend) = 0.005). After adjustment for hypertension and diabetes, the rate ratios were attenuated to nonsignificant levels. Dietary magnesium intake was marginally inversely associated with the incidence of ischemic stroke (P(trend) = 0.09). Low serum magnesium levels could be associated with increased risk of ischemic stroke, in part, via effects on hypertension and diabetes.

Protective effects of magnesium against ischaemia-reperfusion injury through inhibition of P-selectin in rats

1. The leucocyte-mediated inflammatory response plays a pivotal role in ischaemia-reperfusion injury. P-Selectin and CD11b are important mediators for the recruitment of leucocytes into the endothelium. However, the time-course of changes in P-selectin and CD11b expression during reperfusion is not defined. Magnesium has been shown to have a protective role in reperfusion injury, but the mechanism of its action is not yet clear. 2. In the present study, 90 male Sprague-Dawley rats were randomized into three groups, namely a sham-operated group, an IR group (subjected to 45 min of coronary occlusion followed by reperfusion for up to 6 h) and an MgSO(4)-treated group, which received an infusion of MgSO(4) starting 30 min before occlusion and continuing until the onset of reperfusion. The expression of P-selectin on platelets and CD11b on leucocytes, endothelial P-selectin on cardiac microvessels and P-selectin mRNA in myocardial tissue were measured by flow cytometry, immunohistochemistry and reverse transcription-polymerase chain reaction, respectively, at different time points during reperfusion. The degree of myocardial necrosis and arrhythmia was assessed. 3. The present study shows that P-selectin expression on platelets and cardiac microvessels, P-selectin mRNA in myocardial tissue and CD11b expression on leucocytes in the IR group were significantly upregulated compared with the sham-operated group in a time-dependent manner during reperfusion. Treatment with MgSO(4) attenuated the upregulation of P-selectin expression, in addition to inhibiting myocardial necrosis and arrhythmia, but had no effect on CD11b expression on leucocytes. 4. These results suggest that the expression of P-selectin and CD11b is upregulated after reperfusion and magnesium pretreatment plays a cardioprotective role in ischaemia-reperfusion injury, possibly by inhibiting the upregulation of P-selectin expression.

Intracellular magnesium and adipokines in umbilical cord plasma and infant birth size

Many epidemiologic studies have disclosed that restricted fetal growth has been associated with an increased risk of insulin resistance in adulthood. We studied the relationship of intracellular magnesium [Mg2+]i in cord blood platelets to adipocytokine and birth size. The subjects were 20 infants with small for gestational age (SGA) and 45 infants with appropriate for gestational age (AGA). By using a fluorescent probe, we examined [Mg2+]i of platelets in the cord blood. Cord plasma insulin, IGF-I, ghrelin, adiponectin, plasminogen activator inhibitor-1 (PAI-1), and leptin levels were determined with the use of ELISA. Mean [Mg2+]i was lower in the SGA than in the AGA groups (p < 0.001). Adiponectin and IGF-I were also lower in the SGA than in the AGA, whereas PAI-1 was higher in the SGA. [Mg2+]i was significantly correlated with birth weight, birth length, and adiponectin. Birth weight was also correlated with cord plasma IGF-I, adiponectin, and leptin. Quantitative insulin sensitivity check index (QUICKI) was lower in the SGA group than in the AGA group. [Mg]i and adiponectin were correlated with QUICKI in all subjects. [Mg]i, as well as leptin and IGF-I, reflect the extent of fetal growth. Decreased [Mg2+]i may be involved in the underlying processes to insulin resistance.

Associations of calcium and magnesium in serum and hair with bone mineral density in premenopausal women

BACKGROUND AND AIMS

Some minerals have been associated with bone mineral density (BMD) in postmenopausal women or people with certain chronic diseases, but the results have been inconsistent. This study aimed to evaluate the association of serum and hair levels of calcium and magnesium with BMD in premenopausal women.

METHODS

This cross-sectional study of 104 premenopausal volunteers recruited from out-patient clinics and a health promotion center in a university hospital in Seoul, Korea evaluated the association of serum and hair minerals with BMD in premenopausal women. All participants completed BMD measurements at the spine and hip and provided hair for calcium and magnesium analysis; blood was obtained from 68 of these participants for serum analysis.

RESULTS

Higher serum magnesium was associated with lower BMD at the spine (P = 0.047), but a higher hair magnesium was associated with higher BMD at the spine (P = 0.024). The ratio of serum calcium to magnesium was positively associated with BMD at the spine (P = 0.017).

CONCLUSIONS

Magnesium in serum and hair was associated with BMD in premenopausal women. The ratio of serum calcium to magnesium appears to be a significant indicator of BMD.

High-dose folate may improve platelet function in acute coronary syndrome and other pathologies associated with increased platelet oxidative stress

Although nitric oxide of endothelial origin plays a major role in warding off inappropriate thrombus formation, platelets also express the "constitutive" isoform of nitric oxide synthase (cNOS). Activation of this enzyme by calcium influx during platelet aggregation provides an important feedback signal that dampens platelet recruitment. Platelets also express a membrane-bound NAD(P)H oxidase complex, activated by collagen receptors, that produces superoxide. Superoxide can directly quench NO; moreover, by giving rise to peroxynitrite, it can oxidize the cNOS cofactor tetrahydrobiopterin (BH4), thereby suppressing cNOS activity and converting it to superoxide generator. In a canine model of acute coronary syndrome, infusion of BH4 has been shown to prevent thrombus formation. Platelets from patients with acute coronary syndrome produce markedly less NO than do control platelets. A reasonable explanation for these findings is that episodic contact with collagen boosts platelet superoxide production, oxidizing BH4. Since 5-methyltetrahydrofolate can reduce oxidized BH4, or otherwise compensate for its deficiency, supplementation with its precursor folic acid may improve platelet function in acute coronary syndrome and possibly reduce risk for coronary thrombosis in other at-risk patients. Other research demonstrates that superoxide production is increased, and nitric oxide production diminished, in platelets of diabetics; the ability of glutathione--a peroxynitrite scavenger--to largely ameliorate these abnormalities, is consistent with a prominent role for BH4 deficiency in diabetic platelet malfunction. Reports that platelet NO production is decreased, and/or superoxide production increased, in patients with disorders associated with insulin resistance syndrome, suggest that BH4 deficiency--potentially remediable with high-dose folate--may likewise contribute to the platelet hyperreactivity noted in these disorders. Supplemental vitamin C and arginine also have the potential to boost platelet production of NO Increased intakes of taurine, magnesium, gamma-tocopherol, fish oil, and garlic may help to stabilize platelets by additional mechanisms. As a complement to the proven benefits of low-dose aspirin, a supplemental regimen emphasizing these nutrients in appropriate doses may act directly on platelets to further diminish risk for thrombotic episodes.

Magnesium and the inflammatory response: potential physiopathological implications

The purpose of this review is to summarize experimental findings showing that magnesium modulates cellular events involved in inflammation. Experimental magnesium deficiency in the rat induces after a few days a clinical inflammatory syndrome characterized by leukocyte and macrophage activation, release of inflammatory cytokines and acute phase proteins, excessive production of free radicals. Increase in extracellular magnesium concentration, decreases inflammatory response while reduction in the extracellular magnesium results in cell activation. Because magnesium acts as a natural calcium antagonist, the molecular basis for inflammatory response is probably the result of modulation of intracellular calcium concentration. The priming of phagocytic cells, the opening calcium channel and activation of N-methyl-d-aspartate (NMDA) receptors, the activation of nuclear factor-kappa B (NFkappaB) have been considered as potential mechanisms. Moreover, magnesium deficiency induces a systemic stress response by activation of neuro endocrinological pathways. As nervous and immune systems interact bidirectionally, the roles of neuromediators have also been considered. Magnesium deficiency contributes to an exaggerated response to immune stress and oxidative stress is the consequence of the inflammatory response. Inflammation contributes to the pro-atherogenic changes in lipoprotein metabolism, endothelial dysfunction, thrombosis, hypertension and explains the aggravating effect of magnesium deficiency on the development of metabolic syndrome. Further studies are still needed to assess more accurately the role of magnesium in immune response in humans, but these experimental findings in animal models suggest that inflammation is the missing link to explain the role of magnesium in many pathological conditions.

Magnesium deficiency in critical illness

Magnesium (Mg) deficiency commonly occurs in critical illness and correlates with a higher mortality and worse clinical outcome in the intensive care unit (ICU). Magnesium has been directly implicated in hypokalemia, hypocalcemia, tetany, and dysrhythmia. Moreover, Mg may play a role in acute coronary syndromes, acute cerebral ischemia, and asthma. Magnesium regulates hundreds of enzyme systems. By regulating enzymes controlling intracellular calcium, Mg affects smooth muscle vasoconstriction, important to the underlying pathophysiology of several critical illnesses. The principle causes of Mg deficiency are gastrointestinal and renal losses; however, the diagnosis is difficult to make because of the limitations of serum Mg levels, the most common assessment of Mg status. Magnesium tolerance testing and ionized Mg2+ are alternative laboratory assessments; however, each has its own difficulties in the ICU setting. The use of Mg therapy is supported by clinical trials in the treatment of symptomatic hypomagnesemia and preeclampsia and is recommended for torsade de pointes. Magnesium therapy is not supported in the treatment of acute myocardial infarction and is presently undergoing evaluation for the treatment of severe asthma exacerbation, for the prevention of post-coronary bypass grafting dysrhythmias, and as a neuroprotective agent in acute cerebral ischemia.

Relationship of intracellular magnesium of cord blood platelets to birth weight

Magnesium (Mg(2+)) has an important role in insulin action, and insulin stimulates Mg(2+) uptake in insulin-sensitive tissues. Impaired biologic responses to insulin are referred to as insulin resistance. Diabetic patients and obese subjects are reported to have intracellular magnesium ([Mg(2+)](i)) deficiency. Many epidemiologic studies have disclosed that restricted fetal growth has been associated with increased risk of insulin resistance in adult life. We studied the relationship of [Mg(2+)](i) in cord blood platelets to birth weight. The subjects were 19 infants who were small for gestational age (SGA) and 45 who were appropriate for gestational age (AGA). By using a fluorescent probe, mag-fura-2, we examined the basal and insulin-stimulated [Mg(2+)](i) of platelets in the cord blood. Cord plasma insulin-like growth factor-1 (IGF-1)and leptin levels were determined with the use of enzyme-linked immunosorbent assay (ELISA). Birth weight was correlated with cord plasma IGF-1 (P < .001) and leptin (P < .005). Mean basal [Mg(2+)](i), but not plasma Mg(2+), was lower in the SGA than in the AGA group (291 +/- 149 micromol/L v 468 +/- 132 micromol/L, P < .001). The basal [Mg(2+)](i) was significantly correlated with the birth weight (P < .001) as well as birth length (P < .001). At 60 seconds after stimulation with insulin, there was no significant difference in stimulated [Mg(2+)](i) between the SGA and AGA groups. Although the SGA group had low [Mg(2+)](i), the platelets had good potentiality to compensate for low [Mg(2+)](i). [Mg(2+)](i) reflects the extent of fetal growth. Decreased [Mg(2+)](i) in SGA might underlie the initial pathophysiologic events leading to insulin resistance.

Analysis of nitric oxide-sensitive guanylyl cyclase in human platelets before and after aggregation

Nitric oxide (NO) inhibits cell adhesion to vascular endothelium and platelet aggregation through activation of soluble guanylyl cyclase (sGC) and a consequent increase in cGMP. The aim of the present study was to analyze NO-sensitive sGC in human platelets before and after aggregation. NO-sensitive sGC activity was tested in the cytosol and membrane fractions of native human platelets and ADP-induced platelet aggregates in the presence of 3 mM Mn2+ as cofactor. After ADP-induced platelet aggregation there was a significant increase of sGC activity in membranes. Western blot analysis showed a partial translocation of the enzyme to the plasma membrane. These findings support recent data that sGC is associated with cellular membranes in various tissues and cell types and that this membrane association is influenced by the activation state in human platelets (Nat Cell Biol 2002; 4: 307-11). Using 3 mM Mg2+ instead of Mn2+ as cofactor, a sharp decrease of sGC activity was apparent in the cytosol of aggregated platelets. Kinetic analysis of the cytosolic enzyme and concentration-response curves for free Mg2+ showed that platelet aggregation changes binding of free Mg2+ but not binding of the substrate complex Mg.GTP. This effect was specific for free Mg2+ and was not seen for Mn2+. In addition, changes in free Mg2+ concentration in a physiological range markedly influenced NO-stimulated sGC activity. This provides a possible explanation for the increased platelet aggregability in patients with low intraplatelet Mg2+ levels.

Low Serum Magnesium Predicts Neurological Events in Patients With Advanced Atherosclerosis

Background and Purpose— Magnesium (Mg) deficiency is thought to be a risk factor for cerebrovascular atherosclerosis and complications. We investigated the prognostic impact of Mg serum levels with respect to the occurrence of neurological events in patients with advanced atherosclerosis.

Methods— We prospectively studied 323 patients with symptomatic peripheral artery disease and intermittent claudication (197 men; median age, 68 years). Serum Mg was determined, and patients were followed for a median of 20 months (interquartile range, 12 to 25 months) for the occurrence of neurological events, defined as ischemic stroke and/or carotid revascularization (carotid endarterectomy or carotid stenting). Multivariate Cox proportional hazards analysis was applied to assess the association of serum Mg (in tertiles) and neurological events.

Results— Neurological events occurred in 35 patients (11%) (15 patients with stroke, 13 with carotid revascularization, and 7 with stroke and subsequent revascularization). Compared with patients in the highest tertile of Mg serum levels (>0.84 mmol/L), patients with Mg serum values <0.76 mmol/L (lowest tertile) exhibited a 3.29-fold increased adjusted risk (95% CI, 1.34 to 7.90; P=0.009) for neurological events, but patients with Mg serum values of 0.76 mmol/L to 0.84 mmol/L (middle tertile) had no increased risk (adjusted hazard ratio, 1.10; 95% CI, 0.35 to 3.33; P=0.88). Mg serum levels were not associated with all-cause mortality (P=0.87) or coronary events (P=0.67) during follow-up.

Conclusions— Low Mg serum levels indicate an increased risk for neurological events in patients with symptomatic peripheral artery disease, favoring Mg substitution therapy in those patients with advanced atherosclerosis.

Intracellular magnesium of platelets in children with diabetes and obesity

Magnesium (Mg(2+)), the second most abundant intracellular cation, is a critical cofactor in numerous enzymatic reactions. By using a fluorescent probe, mag-fura-2, we examined the basal levels and changes in intracellular Mg(2+)([Mg(2+)](i)) of platelets in diabetic and obese children. Under the basal condition, the platelet [Mg(2+)](i) of both type 1 and type 2 diabetes mellitus (DM) and the obesity groups was significantly lower than the values in the nondiabetic control group (377 +/- 62 micromol/L, 312 +/- 72 micromol/L, 373 +/- 35 micromol/L v 594 +/- 62 micromol/L, respectively, P <.05). [Mg(2+)](i) was increased after the stimulation with 100 microU/mL of insulin. After 60 seconds of insulin stimulation, the value of [Mg(2+)](i) was lower in the type 1 DM group compared with the control group (729 +/- 85 micromol/L v 1,078 +/- 67 micromol/L, P <.005). The increase in percentage over the resting [Mg(2+)](i) was higher in the type 2 DM group than in the stimulated control group (222% +/- 51% v 98% +/- 18 %, P <.05), although the stimulated [Mg(2+)](i) did not reach the level of the control group. The diabetic patients and obese subjects have [Mg(2+)](i) deficiency. In the type 2 DM and obese groups, platelets responded well to insulin. In children under insulin-resistant states, [Mg(2+)](i) decreases before the poor reactivity to insulin occurs in platelets. Decreased [Mg(2+)](i) might underlie the initial pathophysiologic events leading to insulin resistance and abnormality of platelet coagulation.

Does magnesium have a role in the treatment of patients with coronary artery disease?

Hypomagnesemia is common in hospitalized patients, especially in elderly patients with coronary artery disease (CAD) and/or those with chronic heart failure. Hypomagnesemia is associated with increased all cause mortality and mortality from CAD. Magnesium supplementation improves myocardial metabolism, inhibits calcium accumulation and myocardial cell death; it improves vascular tone, peripheral vascular resistance, afterload and cardiac output, reduces cardiac arrhythmias and improves lipid metabolism. Magnesium also reduces vulnerability to oxygen-derived free radicals, improves endothelial function and inhibits platelet function, including platelet aggregation and adhesion, which potentially confers upon magnesium physiologic and natural effects similar to adenosine-diphosphate inhibitors such as clopidogrel. However, data regarding the use of magnesium in patients with acute myocardial infarction (AMI) are conflicting. Although some previous relatively small randomized clinical trials demonstrated a remarkable reduction in mortality when intravenous magnesium was administered to relatively high risk AMI patients, two recently published large-scale randomized clinical trials (the Fourth International Study of Infarct Survival [ISIS 4] and Magnesium in Coronaries [MAGIC]) were unable to demonstrate any advantage of intravenous magnesium over placebo. Nevertheless, the theoretical benefits of magnesium supplementation as a cardio-protective agent in CAD patients, promising results from animal and human studies, its relatively low-cost and ease of handling requiring no special expertise, together with its excellent tolerability, gives magnesium a place in treating CAD patients, especially in those at high risk, such as CAD patients with heart failure, the elderly and hospitalized patients with hypomagnesemia. Furthermore, magnesium therapy is indicated in life-threatening ventricular arrhythmias such as torsades de pointes and intractable ventricular tachycardia.