Neuroprotective effect of magnesium supplementation on cerebral ischemic diseases

Neuroprotection on ischemic brain injury by Mg2+/H2 released from endovascular Mg implant

Most acute ischemic stroke patients with large vessel occlusion require stent implantation for complete recanalization. Yet, due to ischemia-reperfusion injury, over half of these patients still experience poor prognoses. Thus, neuroprotective treatment is imperative to alleviate the ischemic brain injury, and a proof-of-concept study was conducted on "biodegradable neuroprotective stent". This concept is premised on the hypothesis that locally released Mg2+/H2 from Mg metal within the bloodstream could offer synergistic neuroprotection against reperfusion injury in distant cerebral ischemic tissues. Initially, the study evaluated pure Mg's neuroactive potential using oxygen-glucose deprivation/reoxygenation (OGD/R) injured neuron cells. Subsequently, a pure Mg wire was implanted into the common carotid artery of the transient middle cerebral artery occlusion (MCAO) rat model to simulate human brain ischemia/reperfusion injury. In vitro analyses revealed that pure Mg extract aided mouse hippocampal neuronal cell (HT-22) in defending against OGD/R injury. Additionally, the protective effects of the Mg wire on behavioral abnormalities, neural injury, blood-brain barrier disruption, and cerebral blood flow reduction in MCAO rats were verified. Conclusively, Mg-based biodegradable neuroprotective implants could serve as an effective local Mg2+/H2 delivery system for treating distant cerebral ischemic diseases.

The role of metal ions in stroke: Current evidence and future perspectives

Metal ions play a pivotal role in maintaining optimal brain function within the human body. Nevertheless, the accumulation of these ions can result in irregularities that lead to brain damage and dysfunction. Disruptions of metal ion homeostasis can result in various pathologies, including inflammation, redox dysregulation, and blood-brain barrier disruption. While research on metal ions has chiefly focused on neurodegenerative diseases, little attention has been given to their involvement in the onset and progression of stroke. Recent studies have identified cuproptosis and confirmed ferroptosis as significant factors in stroke pathology, underscoring the importance of metal ions in stroke pathology, including abnormal ion transport, neurotoxicity, blood-brain barrier damage, and cell death. Additionally, it provides an overview of contemporary metal ion chelators and detection techniques, which may offer novel approaches to stroke treatment.

The effect of magnesium sulfate on emergence agitation in surgical adult patients undergoing general anesthesia: A systematic review and meta-analysis of randomized controlled trials

STUDY OBJECTIVE

Investigating the effect of magnesium sulfate (MS) on emergence agitation (EA) in adult surgical patients following general anesthesia (GA).

DESIGN

Systematic literature review and meta-analysis (PROSPERO number: CRD42023461988).

SETTING

Review of published literature.

PATIENTS

Adults undergoing GA.

INTERVENTIONS

Intravenous administration of MS.

MEASUREMENTS

We searched PubMed/MEDLINE, EMBASE, the Cochrane Library, Scopus, and Web of Science for publications until September 14, 2023. The primary outcome was the incidence of EA, while the secondary outcomes included the impact of MS on postoperative agitation score (PAS), emergence variables and adverse events. Relative risk (RR) with 95% confidence interval (CI) measured dichotomous outcome, while standardized mean difference (SMD) or mean difference (MD) with 95% CI measured continuous outcomes.

MAIN RESULTS

Meta-analysis of five randomized controlled trials (RCTs) indicated that MS was associated with a lower incidence of EA at various time points (0 min: RR = 0.62, 95% CI [0.41, 0.95]; p = 0.183, I2 = 43.6%; 5 min: RR = 0.29, 95% CI [0.16, 0.52]; p = 0.211, I2 = 36%; 10 min: RR = 0.14, 95% CI [0.06, 0.32]; p = 0.449, I2 = 0%; 15 min: RR = 0.11, 95% CI [0.02, 0.55]; p = 0.265, I2 = 19.5%; 30 min: RR = 0.05, 95% CI [0.00, 0.91]; the postoperative period: RR = 0.21, 95% CI [0.09, 0.49]; p = 0.724, I2 = 0%;). Additionally, MS was associated with a reduced PAS at various time points except for 0 min. However, no significant differences were observed in extubation time, the length of stay in the post-anesthesia care unit, postoperative nausea and vomiting or total complications.

CONCLUSIONS

Limited available evidence suggests that MS was associated with a lower incidence of EA. Nevertheless, further high-quality studies are warranted to strengthen and validate the effect of MS in preventing EA in adult surgical patients.

Caffeic acid alleviates cerebral ischemic injury in rats by resisting ferroptosis via Nrf2 signaling pathway

There are few effective and safe neuroprotective agents for the treatment of ischemic stroke currently. Caffeic acid is a phenolic acid that widely exists in a number of plant species. Previous studies show that caffeic acid ameliorates brain injury in rats after cerebral ischemia/reperfusion. In this study we explored the protective mechanisms of caffeic acid against oxidative stress and ferroptosis in permanent cerebral ischemia. Ischemia stroke was induced on rats by permanent middle cerebral artery occlusion (pMCAO). Caffeic acid (0.4, 2, 10 mg·kg-1·d-1, i.g.) was administered to the rats for 3 consecutive days before or after the surgery. We showed that either pre-pMCAO or post-pMCAO administration of caffeic acid (2 mg·kg-1·d-1) effectively reduced the infarct volume and improved neurological outcome. The therapeutic time window could last to 2 h after pMCAO. We found that caffeic acid administration significantly reduced oxidative damage as well as neuroinflammation, and enhanced antioxidant capacity in pMCAO rat brain. We further demonstrated that caffeic acid down-regulated TFR1 and ACSL4, and up-regulated glutathione production through Nrf2 signaling pathway to resist ferroptosis in pMCAO rat brain and in oxygen glucose deprivation/reoxygenation (OGD/R)-treated SK-N-SH cells in vitro. Application of ML385, an Nrf2 inhibitor, blocked the neuroprotective effects of caffeic acid in both in vivo and in vitro models, evidenced by excessive accumulation of iron ions and inactivation of the ferroptosis defense system. In conclusion, caffeic acid inhibits oxidative stress-mediated neuronal death in pMCAO rat brain by regulating ferroptosis via Nrf2 signaling pathway. Caffeic acid might serve as a potential treatment to relieve brain injury after cerebral ischemia. Caffeic acid significantly attenuated cerebral ischemic injury and resisted ferroptosis both in vivo and in vitro. The regulation of Nrf2 by caffeic acid initiated the transcription of downstream target genes, which were shown to be anti-inflammatory, antioxidative and antiferroptotic. The effects of caffeic acid on neuroinflammation and ferroptosis in cerebral ischemia were explored in a primary microglia-neuron coculture system. Caffeic acid played a role in reducing neuroinflammation and resisting ferroptosis through the Nrf2 signaling pathway, which further suggested that caffeic acid might be a potential therapeutic method for alleviating brain injury after cerebral ischemia.

A new multi-parameter imaging platform for in vivo drug efficacy evaluation of ischemic stroke

Ischemic stroke with high incidence and disability rate severely endangers human health. Current clinical treatment strategies are quite limited, new drugs for ischemic stroke are urgently needed. However, most existing methods for the efficacy evaluation of new drugs possess deficiencies of divorcing from the true biological context, single detection indicator and complex operations, leading to evaluation biases and delaying drug development process. In this work, leveraging the advantages of fluorescence imaging with non-invasive, real-time, in-situ, high selectivity and high sensitivity, a new multi-parameter simultaneous fluorescence imaging platform (MPSFL-Platform) based on two fluorescence materials was constructed to evaluate the efficacy of new drug for ischemic stroke. Through simultaneous fluorescence observing three key indicators of ischemic stroke, malondialdehyde (MDA), formaldehyde (FA), and monoamine oxidase A (MAO-A), the efficacy evaluations of three drugs for ischemic stroke were real-time and in-situ performed. Compared with edaravone and butylphthalide, edaravone dexborneol exhibited better therapeutic effect by using MPSFL-Platform. The successful establishment of MPSFL-Platform is serviceable to accelerate the conduction of preclinical trial and the exploration of pathophysiology mechanism for drugs related to ischemic stroke and other brain diseases, which is perspective to promote the efficiency of new drug development.

Changes in metabolite content in the kidneys and skeletal muscles of rats fed magnesium-restricted diets

A metabolomic study was performed on the kidneys and skeletal muscles of rats fed diets containing varying contents of Mg for 4 weeks. The kidneys are divided into two parts, the aerobic cortex and the anaerobic medulla, that differ in metabolism. The relative contents of 3-phosphoglyceric acid, 2-phosphoglyceric acid, and phosphoenolpyruvic acid increased with Mg restriction in both renal regions. In contrast, pyruvic acid content decreased with Mg restriction in the diets, suggesting an inhibitory conversion of phosphoenolpyruvic acid to pyruvic acid. The lactic acid content increased in both regions of the kidneys of Mg-restricted rats, implying changes towards a more glycolytic metabolism, possibly resulting from the impairment of mitochondrial function. There are two types of muscle fibers: glycolytic fast and oxidative slow muscle fibers. The soleus muscle consists of slow muscle fibers, whereas the gastrocnemius muscle consists of a combination of fast and slow muscle fibers. Similar to the changes in the kidneys, the contents of 3-phosphoglyceric acid, 2-phosphoglyceric acid, phosphoenolpyruvic acid, and lactic acid increased in the soleus and gastrocnemius muscles with dietary Mg restriction. Unlike in the kidney, pyruvic acid content increased in the soleus muscle in response to Mg restriction. Severe Mg restriction decreased contents of carnosine and its constituent β-alanine and increased the levels of purine derivatives such as xanthine and uric acid in the gastrocnemius muscle. The present study suggests a region-dependent sensitivity to dietary restriction of Mg, which may lead to the onset of various metabolic disorders.

Research progress and perspectives of N-methyl-D-aspartate receptor in myocardial and cerebral ischemia-reperfusion injury: A review

There is an urgent need to find common targets for precision therapy, as there are no effective preventive therapeutic measures for combined clinical heart-brain organ protection and common pathways associated with glutamate receptors are involved in heart-brain injury, but current glutamate receptor-related clinical trials have failed. Ischemia-reperfusion injury (IRI) is a common pathological condition that occurs in multiple organs, including the heart and brain, and can lead to severe morbidity and mortality. N-methyl-D-aspartate receptor (NMDAR), a type of ionotropic glutamate receptor, plays a crucial role in the pathogenesis of IRI. NMDAR activity is mainly regulated by endogenous activators, agonists, antagonists, and voltage-gated channels, and activation leads to excessive calcium influx, oxidative stress, mitochondrial dysfunction, inflammation, apoptosis, and necrosis in ischemic cells. In this review, we summarize current research advances regarding the role of NMDAR in myocardial and cerebral IRI and discuss potential therapeutic strategies to modulate NMDAR signaling to prevent and treat IRI.

The effects of protein-rich extract from Rhizoma Gastrodiae against cerebral ischemia/reperfusion injury via regulating MAPK and PI3K/AKT signaling pathway

BACKGROUND

Rhizoma Gastrodiae is a highly valuable traditional Chinese medicine and functional health food that has been used in China to treat neurological disorders for thousands of years. Rhizoma Gastrodiae contains various of biological activities, such as antioxidative, neuroprotective, learning improvement, anxiolytic, and antidepressant effects. However, no studies have been conducted to explore the effects of the protein components in Rhizoma Gastrodiae (GEPS) and its potential protective effects against ischemic stroke.Our main goal was to investigate the effects of GEPS on ischemia/reperfusion (I/R) injury and its possible mechanisms.

METHODS

A middle cerebral artery occlusion (MCAO) induced focal cerebral ischemia mouse model and an oxygen-glucose deprivation (OGD/R) injury model in HT22 cells were established. A neurobehavioral test was performed 24 h after MCAO, and brain infarction was measured. A Morris water maze experiment was conducted on Day 14 after reperfusion in mice. Hematoxylin and eosin (HE) and TUNEL staining were performed to assess apoptotic neuronal death. Immunohistochemical analysis was used to detect BDNF and GAP43 expression. The content of SOD, MDA, GSH-PX and ROS were detected. The protein expression was analyzed using Western blotting. Cell viability was determined by MTT assay. Cell apoptosis was examined by flow cytometry.

RESULTS

GEPS reduced apoptosis, decreased cerebral infarction, improved neurological defects, and ameliorated oxidative stress in the ischemic penumbra. In addition, GEPS increased the expression of BDNF and GA43 in the penumbra. Mechanistically, GEPS counteracted MCAO-induced PI3K/AKT inhibition and activation of MAPK signaling pathways.

CONCLUSION

GEPS has a clear neuroprotective effect on I/R injury, and its mechanism may be linked to the PI3K/AKT and MAPK signaling pathways.

Neuroprotective Effects of Tryptanthrin-6-Oxime in a Rat Model of Transient Focal Cerebral Ischemia

The activation of c-Jun N-terminal kinase (JNK) plays an important role in stroke outcomes. Tryptanthrin-6-oxime (TRYP-Ox) is reported to have high affinity for JNK and anti-inflammatory activity and may be of interest as a promising neuroprotective agent. The aim of this study was to investigate the neuroprotective effects of TRYP-Ox in a rat model of transient focal cerebral ischemia (FCI), which involved intraluminal occlusion of the left middle cerebral artery (MCA) for 1 h. Animals in the experimental group were administered intraperitoneal injections of TRYP-Ox 30 min before reperfusion and 23 and 47 h after FCI. Neurological status was assessed 4, 24, and 48 h following FCI onset. Treatment with 5 and 10 mg/kg of TRYP-Ox decreased mean scores of neurological deficits by 35-49 and 46-67% at 24 and 48 h, respectively. At these doses, TRYP-Ox decreased the infarction size by 28-31% at 48 h after FCI. TRYP-Ox (10 mg/kg) reduced the content of interleukin (IL) 1β and tumor necrosis factor (TNF) in the ischemic core area of the MCA region by 33% and 38%, respectively, and attenuated cerebral edema by 11% in the left hemisphere, which was affected by infarction, and by 6% in the right, contralateral hemisphere 24 h after FCI. TRYP-Ox reduced c-Jun phosphorylation in the MCA pool at 1 h after reperfusion. TRYP-Ox was predicted to have high blood-brain barrier permeability using various calculated descriptors and binary classification trees. Indeed, reactive oxidant production was significantly lower in the brain homogenates from rats treated with TRYP-Ox versus that in control animals. Our data suggest that the neuroprotective activity of TRYP-Ox may be due to the ability of this compound to inhibit JNK and exhibit anti-inflammatory and antioxidant activity. Thus, TRYP-Ox may be considered a promising neuroprotective agent that potentially could be used for the development of new treatment strategies in cerebral ischemia.

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.

Inhibition of the postsynaptic density protein 95 on the protective effect of Ang-(1-7)-Mas on cerebral ischaemia injury

BACKGROUND

Postsynaptic density protein-95 (PSD95) plays an important role in cerebral ischaemia injury, but its mechanism needs further research. This study aimed to explore the role of PSD95 in (Ang-(1-7))-Mas-mediated cerebral ischaemia protection and its regulatory mechanism.

METHODS

Oxygen-glucose deprivation (OGD) neuron and rat middle cerebral artery occlusion (MCAO) models were used as in vitro and in vivo models, respectively. TAT-MAS9C was used to disrupt the interaction between PSD95 and Mas. The recombinant PSD95 adenovirus (Ad-PSD95) was used to overexpress PSD95 in neurons.

RESULTS

Results showed that in OGD neurons, Ang-(1-7) could promote cell viability; reduce cell apoptosis; reduce the cell membrane localisation of Mas; upregulate the expression levels of pAKT, bcl-2 and I-κB; and downregulate the expression levels of Bax, pI-κB, tumour necrosis factor alpha and interleukin-1β. TAT-MAS9C could enhance the aforementioned effects of Ang-(1-7). However, the PSD95 overexpression inhibited the aforementioned effects of Ang-(1-7). In the MCAO rat model, the 2,3,5-triphenyltetrazolium chloride (TTC) staining showed that Ang-(1-7) reduced the infarct volume. The Morris water maze test showed that the number of crossings over the platform area in the Ang-(1-7) group was significantly increased. TAT-MAS9C could promote the protective effect of Ang-(1-7).

CONCLUSIONS

Results suggested that PSD95 alleviated the activation of AKT and the inhibition of nuclear factor kappa B signalling pathway mediated by the Ang-(1-7)-Mas complex, thereby reducing neuronal activity, increasing apoptosis and inhibiting the Ang-(1-7)-Mas-mediated cerebral ischaemia protection.

Legumain knockout improved cognitive impairment via reducing neuroinflammation in right unilateral common carotid artery occlusion mice

AIMS

Chronic cerebral hypoperfusion (CCH) is a state of chronic cerebral blood flow reduction, and it is the main cause of cognitive impairment and neurodegenerative diseases. The abnormal upregulation of legumain, a lysosomal cysteine protease, trigger synaptic plasticity impairment and neuroinflammation, which are involved in the underlying pathophysiology of CCH. At present, few studies have reported the role of legumain in cognitive impairment caused by CCH. In our study, we aimed to investigate the involvement of legumain knockout in cognitive function and neuroinflammation in a CCH mouse model.

MAIN METHODS

In this study, right unilateral common carotid artery occlusion (rUCCAO) was used to simulate the pathological state of cerebral ischemic injury. Various behavioural tests were executed to assess cognitive performance. In vivo electrophysiological recordings were used to measure synaptic functions. Western blotting, Golgi staining, haematoxylin/eosin staining, and immunofluorescence assays were conducted to examine pathological changes and molecular mechanisms.

KEY FINDINGS

The data showed that the level of legumain was significantly increased in the hippocampus of mice subjected to rUCCAO. Legumain knockout significantly improved cognitive function and synaptic plasticity induced by rUCCAO, suggesting that legumain knockout-regulation effectively protected against CCH-induced behavioural dysfunctions. Moreover, legumain knockout suppressed rUCCAO-induced microglial activation, reduced the abnormal expression of inflammatory cytokines and the inflammasome complex, and impeded the activation of P65 and pyroptosis.

SIGNIFICANCE

These findings suggest that legumain is an effective regulator of CCH, and may be an ideal target for the development of cerebral ischemia treatments in the future.

Basic considerations on magnesium in the management of neurocritical patients

Magnesium is an essential chemical element in human life. In the brain, it is physiologically responsible for a large number of processes involved in intracellular homeostasis, blood-brain barrier integrity, protein synthesis, neuronal proliferation, aging, and apoptosis. Considering that neurocritical care is a relatively new discipline in certain regions of the world and is an independent protective factor of neurological diseases in critical care, it is essential to disseminate basic concepts and utilities of tools that can positively impact the neurological disease burden. Magnesium and its use in neurocritical care are poorly understood. Therefore, this study aimed to review basic concepts regarding the physiology of magnesium in neurological dynamics, its role in the pathophysiology of neurological disorders, and the outcome of its use in the management of neurocritical illnesses.

Cross-Talks between the Cardiovascular Disease-Sarcopenia-Osteoporosis Triad and Magnesium in Humans

Magnesium (Mg) is a pivotal and very complex component of healthy aging in the cardiovascular-muscle-bone triad. Low Mg levels and low Mg intake are common in the general aging population and are associated with poorer outcomes than higher levels, including vascular calcification, endothelial dysfunction, osteoporosis, or muscle dysfunction/sarcopenia. While Mg supplementation appears to reverse these processes and benefit the triad, more randomized clinical trials are needed. These will allow improvement of preventive and curative strategies and propose guidelines regarding the pharmaceutical forms and the dosages and durations of treatment in order to optimize and adapt Mg prescription for healthy aging and for older vulnerable persons with comorbidities.