Erythrocyte intracellular Mg(2+) concentration as an index of recognition and memory

Hybridization chain reaction-DNAzyme amplified switch microplate assay for ultrasensitive detection of magnesium ions

It is well-recognized that metal ion contaminants present in food and the environment pose a serious threat to human health and contribute to huge economic losses. Therefore, the development of simple, rapid, sensitive, and on-site methods for the detection of metal ions has become an urgent need. Herein, we combined the isothermal hybridization chain reaction (HCR) and a DNAzyme to develop a dual-signal amplification sensing assay for ultrasensitive Mg2+ detection on microplates. In this assay, the linker DNA strand (LDNA) that triggered the formation of the HCR structure was immobilized on a microplate via the biotin-streptavidin conjugation. Upon addition of the H5 sequence substrate strand to form a DNAzyme structure, an amplification switch microplate with 2n signaling amplification sites was established. The HCR-DNAzyme switch was activated by capturing Mg2+, and the methylene blue (MB)-labeled H5 was released. It generated an electrochemical signal after being captured by the reporter electrode attached to its complementary sequence (CDNA), accomplishing an efficient detection of Mg2+. Moreover, owing to the 2n signal amplification of the HCR-DNAzyme system with the simple separation and purification processing of the microplate, the Mg2+ detection limit of this strategy was as low as 0.6 fM. Furthermore, this method could be employed for other targets by simply changing the recognition structure of the DNAzyme, revealing the potential practical applications of this strategy in a wide range of fields.

The Impact of Chronic Magnesium Deficiency on Excitable Tissues-Translational Aspects

Neuromuscular excitability is a vital body function, and Mg2+ is an essential regulatory cation for the function of excitable membranes. Loss of Mg2+ homeostasis disturbs fluxes of other cations across cell membranes, leading to pathophysiological electrogenesis, which can eventually cause vital threat to the patient. Chronic subclinical Mg2+ deficiency is an increasingly prevalent condition in the general population. It is associated with an elevated risk of cardiovascular, respiratory and neurological conditions and an increased mortality. Magnesium favours bronchodilation (by antagonizing Ca2+ channels on airway smooth muscle and inhibiting the release of endogenous bronchoconstrictors). Magnesium exerts antihypertensive effects by reducing peripheral vascular resistance (increasing endothelial NO and PgI2 release and inhibiting Ca2+ influx into vascular smooth muscle). Magnesium deficiency disturbs heart impulse generation and propagation by prolonging cell depolarization (due to Na+/K+ pump and Kir channel dysfunction) and dysregulating cardiac gap junctions, causing arrhythmias, while prolonged diastolic Ca2+ release (through leaky RyRs) disturbs cardiac excitation-contraction coupling, compromising diastolic relaxation and systolic contraction. In the brain, Mg2+ regulates the function of ion channels and neurotransmitters (blocks voltage-gated Ca2+ channel-mediated transmitter release, antagonizes NMDARs, activates GABAARs, suppresses nAChR ion current and modulates gap junction channels) and blocks ACh release at neuromuscular junctions. Magnesium exerts multiple therapeutic neuroactive effects (antiepileptic, antimigraine, analgesic, neuroprotective, antidepressant, anxiolytic, etc.). This review focuses on the effects of Mg2+ on excitable tissues in health and disease. As a natural membrane stabilizer, Mg2+ opposes the development of many conditions of hyperexcitability. Its beneficial recompensation and supplementation help treat hyperexcitability and should therefore be considered wherever needed.

Method validation of an inductively coupled plasma mass spectrometry (ICP-MS) assay for the analysis of magnesium, copper and zinc in red blood cells

Background

Laboratory measurements of trace elements such as magnesium (Mg), copper (Cu), and zinc (Zn) in red blood cells (RBCs) are essential for assessing nutritional status and diagnosing metal toxicity. The purpose of this study was to develop and validate an ICP-MS method for quantifying these elements in RBCs.

Methods

Packed RBCs were aliquoted and diluted in an alkaline diluent solution containing internal standards, 0.1 % Triton X-100, 0.1 % EDTA, and 1 % ammonium hydroxide. The resulting diluted specimen was analyzed using inductively coupled plasma mass spectrometry (ICP-MS) to quantitatively determine the levels of Mg, Cu, and Zn. The method underwent validation for accuracy, precision, method comparison, linearity, analytical sensitivity, and carryover. Additionally, retrospective data were analyzed, and non-parametric reference intervals were calculated.

Results

Accuracy and linearity fell within the expected range of ≤±15 % for all analytes. Within-run, between-run, and total imprecision were ≤15 % coefficient of variation. All other validation experiments met the established acceptance criteria. Retrospective data analysis was conducted on patient samples using the method. The application of Tukey's HSD test for multiple comparisons revealed statistically significant mean differences (p < 0.05) in Mg, Cu, and Zn concentrations between all pairwise groups of age and sex, except for the mean Cu concentration in adult males versus females and the mean Mg concentrations in adult versus minor males.

Conclusions

The presented method was successfully validated and met the criteria for clinical use. Retrospective data analysis of patient results demonstrated the method's suitability for assessing nutritional deficiency and toxicity.

Magnesium (Mg2+): Essential Mineral for Neuronal Health: From Cellular Biochemistry to Cognitive Health and Behavior Regulation

Magnesium (Mg2+) is a crucial mineral involved in numerous cellular processes critical for neuronal health and function. This review explores the multifaceted roles of Mg2+, from its biochemical interactions at the cellular level to its impact on cognitive health and behavioral regulation. Mg2+ acts as a cofactor for over 300 enzymatic reactions, including those involved in ATP synthesis, nucleic acid stability, and neurotransmitter release. It regulates ion channels, modulates synaptic plasticity, and maintains the structural integrity of cell membranes, which are essential for proper neuronal signaling and synaptic transmission. Recent studies have highlighted the significance of Mg2+ in neuroprotection, showing its ability to attenuate oxidative stress, reduce inflammation, and mitigate excitotoxicity, thereby safeguarding neuronal health. Furthermore, Mg2+ deficiency has been linked to a range of neuropsychiatric disorders, including depression, anxiety, and cognitive decline. Supplementation with Mg2+, particularly in the form of bioavailable compounds such as Magnesium-L-Threonate (MgLT), Magnesium-Acetyl-Taurate (MgAT), and other Magnesium salts, has shown some promising results in enhancing synaptic density, improving memory function, and alleviating symptoms of mental health disorders. This review highlights significant current findings on the cellular mechanisms by which Mg2+ exerts its neuroprotective effects and evaluates clinical and preclinical evidence supporting its therapeutic potential. By elucidating the comprehensive role of Mg2+ in neuronal health, this review aims to underscore the importance of maintaining optimal Mg2+ levels for cognitive function and behavioral regulation, advocating for further research into Mg2+ supplementation as a viable intervention for neuropsychiatric and neurodegenerative conditions.

A Closed-Loop Autologous Erythrocyte-Mediated Delivery Platform for Diabetic Nephropathy Therapy

Failure to control blood glucose level (BGL) may aggravate oxidative stress and contribute to the development of diabetic nephropathy (DN). Using erythrocytes (ERs) as the carriers, a smart self-regulatory insulin (INS) release system was constructed to release INS according to changes in BGLs to improve patients' compliance and health. To overcome the limited sources of ERs and decrease the risk of transmitting infections, we developed an in vitro, closed-loop autologous ER-mediated delivery (CAER) platform, based on a commercial hemodialysis instrument modified with a glucose-responsive ER-based INS delivery system (GOx-INS@ER). After the blood was drained via a jugular vein cannula, some of the blood was pumped into the CAER platform. The INS was packed inside the autologous ERs in the INS reactor, and then their surface was modified with glucose oxidase (GOx), which acts as a glucose-activated switch. In vivo, the CAER platform showed that the BGL responsively controlled INS release in order to control hyperglycemia and maintain the BGL in the normal range for up to 3 days; plus, there was good glycemic control without the added burden of hemodialysis in DN rabbits. These results demonstrate that this closed-loop extracorporeal hemodialysis platform provides a practical approach for improving diabetes management in DN patients.

The Role of Magnesium in Pregnancy and in Fetal Programming of Adult Diseases

Magnesium is an essential trace metal and a necessary factor for multiple biochemical functions in humans. Its role in biology is fundamental in over 600 enzymatic reactions implicated in protein synthesis, mitochondrial functions, neuromuscular activity, bone formation, and immune system competence. Magnesium status is relevant in fetal development during gestation and in the newborn growth during the perinatal period. Moreover, magnesium is able to influence fetal programming and disease presentation in childhood or adulthood. The aim of this review is to focus on this metal homeostasis, analyzing its normal values, the causes of hypomagnesemia, the interaction with drugs and other conditions, and the diseases associated with magnesium value alteration during pregnancy, in order to study its role in fetal programming of adult diseases. The data here reported clearly indicated the existence of a connection between magnesium status and human pathology starting from intrauterine life and extending into childhood and adulthood.

Intra-erythrocytes magnesium deficiency could reflect cognitive impairment status due to vascular disease: a pilot study

Background and aims

Magnesium is a fundamental cation that regulates neuronal transmission, protein synthesis, energy metabolism. Magnesium deficiency mostly affects nervous and cardiovascular systems determining weakness, tremors, seizure and arrhythmias. This condition retains also a role in memory function and neuronal plasticity. Importantly magnesium deficiency could remain latent and asymptomatic resulting a risk factor for cardiovascular disease. In this sense we aim to determine magnesium status in patient presenting cognitive impairment of vascular origin.

Methods

21 healthy subjects and 27 patients presenting vascular cognitive impairment were included in this study. Both plasma and intraerythrocitary magnesium level were measured to detect magnesium deficiency and cognitive performance was evaluated trough Mini Mental State Evaluation (MMSE).

Results

Here we showed that patients presenting vascular cognitive impairment present intraerythrocitary magnesium level lower than age-matched healthy subjects. To note their plasma magnesium resulted within reference limit.

Conclusion

We suggest that intracellular magnesium laboratory measurement is needed to detect occult magnesium deficiency in population at risk. Magnesium supplementation could represent an adjuvant for healthy aging in high risk population.

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

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

Magnesium: The overlooked electrolyte in blood cancers?

Magnesium is an important element that has essential roles in the regulation of cell growth, division, and differentiation. Mounting evidence in the literature suggests an association between hypomagnesemia and all-cause mortality. In addition, epidemiologic studies have demonstrated that a diet poor in magnesium increases the risk of developing cancer, highlighting its importance in the field of hematology and oncology. In solid malignancies, hypomagnesemia at diagnosis portends a worse prognosis. However, little is known about prognosis in patients with hypomagnesemia and blood cancers in general; lymphoma more specifically. Hypomagnesemia has been associated with a higher viral load of the Epstein Barr virus, a virus associated with a multitude of hematologic malignancies. The role of magnesium in the immune system has been further elucidated in studies of patients with a rare primary immunodeficiency known as XMEN disease (X-linked immunodeficiency with Magnesium defect, Epstein-Barr virus (EBV) infection, and Neoplasia disease). These patients have a mutation in the MAGT1 gene, which codes for a magnesium transporter. The mutation leads to impaired T cell activation and an increased risk of developing hematologic malignancies. In this review we discuss the relevance of magnesium as an electrolyte, current measurement techniques, and the known data related to cause and prognosis of blood cancers. The goal is to use these data to stimulate additional high-quality and well powered studies to further investigate the role of magnesium in preventing cancer and improving outcomes of patients with malignancy and concomitant magnesium deficiency.

Associations of maternal zinc and magnesium with offspring learning abilities and cognitive development at 4 years in GUSTO

Objectives: Minerals deficiencies during pregnancy have been shown to be associated with poorer cognitive outcomes in offspring. This study aimed to investigate associations of maternal plasma zinc and magnesium concentrations with cognitive development in 4-year old children from the Growing Up in Singapore Towards healthy Outcome cohort.Methods: Maternal plasma zinc and magnesium concentrations were measured at 26-28 weeks' gestation. The Lollipop test of school readiness, tests of working memory, number knowledge, receptive vocabulary, and phonological awareness were performed in children at 4 years. Associations were examined in 715 mother-offspring pairs using linear regressions adjusted for key confounders.Results: Maternal plasma zinc and magnesium concentrations were 812 ± 144 µg/L and 19.9 ± 1.8 mg/L (mean±SD); 19% and 71% of mothers were zinc deficient and magnesium insufficient, respectively. After adjustment for multiple testing, higher maternal zinc concentrations (per SD increment) were associated with 0.35 higher scores in Lollipop subtest 2 of picture description and spatial identification (95% CI: 0.13, 0.58); higher maternal magnesium concentrations (per SD increment) were associated with 0.65 higher scores in Lollipop subtest 4 of letters and writing identification (95% CI: 0.23, 1.07).Discussion: No significant associations were observed for other tests, suggesting little long term influences of maternal zinc and magnesium on child's cognitive development.

Magnesium Is a Key Player in Neuronal Maturation and Neuropathology

Magnesium (Mg) is the second most abundant cation in mammalian cells, and it is essential for numerous cellular processes including enzymatic reactions, ion channel functions, metabolic cycles, cellular signaling, and DNA/RNA stabilities. Because of the versatile and universal nature of Mg²⁺, the homeostasis of intracellular Mg²⁺ is physiologically linked to growth, proliferation, differentiation, energy metabolism, and death of cells. On the cellular and tissue levels, maintaining Mg²⁺ within optimal levels according to the biological context, such as cell types, developmental stages, extracellular environments, and pathophysiological conditions, is crucial for development, normal functions, and diseases. Hence, Mg²⁺ is pathologically involved in cancers, diabetes, and neurodegenerative diseases, such as Parkinson's disease, Alzheimer's disease, and demyelination. In the research field regarding the roles and mechanisms of Mg²⁺ regulation, numerous controversies caused by its versatility and complexity still exist. As Mg²⁺, at least, plays critical roles in neuronal development, healthy normal functions, and diseases, appropriate Mg²⁺ supplementation exhibits neurotrophic effects in a majority of cases. Hence, the control of Mg²⁺ homeostasis can be a candidate for therapeutic targets in neuronal diseases. In this review, recent results regarding the roles of intracellular Mg²⁺ and its regulatory system in determining the cell phenotype, fate, and diseases in the nervous system are summarized, and an overview of the comprehensive roles of Mg²⁺ is provided.

A Direct Quantitative Analysis of Erythrocyte Intracellular Ionized Magnesium in Physiological and Pathological Conditions

Magnesium (Mg²⁺) is an endogenous cation that is involved in many essential biological reactions. Abnormal Mg²⁺ metabolisms in the body affect important physiological and pathological processes. However, most endogenous Mg²⁺ markers fail to represent body Mg²⁺ status; they are disadvantageous in terms of representational capacity, applied range, operational convenience, etc. In this article, we evaluated some of the most popular Mg²⁺ marker candidates. A logical model of the blood Mg²⁺ compartments was established, which consisted of unstable Mg²⁺ pools, representative Mg²⁺ pools, and conserved Mg²⁺ pools. These pools were based on the metabolic efficiency of Mg²⁺ in an acute Mg²⁺ intake test. The results of this study showed that only the erythrocyte intracellular ionized Mg²⁺ (RBC [Mg²⁺]_i), a representative Mg²⁺ pool, could effectively represent abnormal body Mg²⁺ metabolisms in various conditions, including dietary Mg²⁺ adjustments, aging and metabolic syndrome. These results suggest that RBC [Mg²⁺]_i might be a widely applicable marker of body Mg²⁺ levels. On unified technology platform and evaluation system, this research compared the representative capacities of RBC [Mg²⁺]_i, plasma Mg²⁺ concentration (plasma [Mg²⁺]), erythrocyte intracellular total Mg (RBC [Mg]_total) and Mg retention in rats and mice under various Mg²⁺-metabolism-related physiological and pathological conditions. Our technique for the direct quantitative analysis of RBC [Mg²⁺]_i may prove valuable for basic physiological research, dietary Mg²⁺ regulation, as well as clinical monitoring/intervention of Mg²⁺-metabolism-related pathology.

Alterations of Mg2+ After Hemorrhagic Shock

Hemorrhagic shock is generally characterized by hemodynamic instability with cellular hypoxia and diminishing cellular function, resulting from an imbalance between systemic oxygen delivery and consumption and redistribution of fluid and electrolytes. Magnesium (Mg) is the fourth most abundant cation overall and second most abundant intracellular cation in the body and an essential cofactor for the energy production and cellular metabolism. Data for blood total Mg (tMg; free-ionized, protein-bound, and anion-bound forms) and free Mg²⁺ levels after a traumatic injury are inconsistent and only limited information is available on hemorrhagic effects on free Mg²⁺ as the physiologically active form. The aim of this study was to determine changes in blood Mg²⁺ and tMg after hemorrhage in rats identifying mechanism and origin of the changes in blood Mg²⁺. Hemorrhagic shock produced significant increases in blood Mg²⁺, plasma tMg, Na⁺, K⁺, Cl^-, anion gap, partial pressures of oxygen, glucose, and blood urea nitrogen but significant decreases in RBC tMg, blood Ca²⁺, HCO₃^-, pH, partial pressures of carbon dioxide, hematocrit, hemoglobin, total cholesterol, and plasma/RBC ATP. During hemorrhagic shock, K⁺, anion gap, and BUN showed significant positive correlations with changes in blood Mg²⁺ level, while Ca²⁺, pH, and T-CHO correlated to Mg²⁺ in a negative manner. In conclusion, hemorrhagic shock induced an increase in both blood-free Mg²⁺ and tMg, resulted from Mg²⁺ efflux from metabolic damaged cell with acidosis and ATP depletion.