Magnesium Regulates Endothelial Barrier Functions through TRPM7, MagT1, and S1P1

Magnesium Ions Promote the Induction of Immunosuppressive Bone Microenvironment and Bone Repair through HIF-1α-TGF-β Axis in Dendritic Cells

The effect of immunoinflammation on bone repair during the recovery process of bone defects needs to be further explored. It is reported that Mg2+ can promote bone repair with immunoregulatory effect, but the underlying mechanism on adaptive immunity is still unclear. Here, by using chitosan and hyaluronic acid-coated Mg2+ (CSHA-Mg) in bone-deficient mice, it is shown that Mg2+ can inhibit the activation of CD4+ T cells and increase regulatory T cell formation by inducing immunosuppressive dendritic cells (imDCs). Mechanistically, Mg2+ initiates the activation of the MAPK signaling pathway through TRPM7 channels on DCs. This process subsequently induces the downstream HIF-1α expression, a transcription factor that amplifies TGF-β production and inhibits the effective T cell function. In vivo, knock-out of HIF-1α in DCs or using a HIF-1α inhibitor PX-478 reverses inhibition of bone inflammation and repair promotion upon Mg2+-treatment. Moreover, roxadustat, which stabilizes HIF-1α protein expression, can significantly promote immunosuppression and bone repair in synergism with CSHA-Mg. Thus, the findings identify a key mechanism for DCs and its HIF-1α-TGF-β axis in the induction of immunosuppressive bone microenvironment, providing potential targets for bone regeneration.

Transient Receptor Potential Channels in the Healthy and Diseased Blood-Brain Barrier

The large family of transient receptor potential (TRP) channels are integral membrane proteins that function as environmental sensors and act as ion channels after activation by mechanical (touch), physical (heat, pain), and chemical stimuli (pungent compounds such as capsaicin). Most TRP channels are localized in the plasma membrane of cells but some of them are localized in membranes of organelles and function as intracellular Ca2+-ion channels. TRP channels are involved in neurological disorders but their precise role(s) and relevance in these disorders are not clear. Endothelial cells of the blood-brain barrier (BBB) express TRP channels such as TRP vanilloid 1-4 and are involved in thermal detection by regulating BBB permeability. In neurological disorders, TRP channels in the BBB are responsible for edema formation in the brain. Therefore, drug design to modulate locally activity of TRP channels in the BBB is a hot topic. Today, the application of TRP channel antagonists against neurological disorders is still limited.

Intrinsic endothelial hyperresponsiveness to inflammatory mediators drives acute episodes in models of Clarkson disease

Clarkson disease, or monoclonal gammopathy-associated idiopathic systemic capillary leak syndrome (ISCLS), is a rare, relapsing-remitting disorder featuring the abrupt extravasation of fluids and proteins into peripheral tissues, which in turn leads to hypotensive shock, severe hemoconcentration, and hypoalbuminemia. The specific leakage factor(s) and pathways in ISCLS are unknown, and there is no effective treatment for acute flares. Here, we characterize an autonomous vascular endothelial defect in ISCLS that was recapitulated in patient-derived endothelial cells (ECs) in culture and in a mouse model of disease. ISCLS-derived ECs were functionally hyperresponsive to permeability-inducing factors like VEGF and histamine, in part due to increased endothelial nitric oxide synthase (eNOS) activity. eNOS blockade by administration of N(γ)-nitro-l-arginine methyl ester (l-NAME) ameliorated vascular leakage in an SJL/J mouse model of ISCLS induced by histamine or VEGF challenge. eNOS mislocalization and decreased protein phosphatase 2A (PP2A) expression may contribute to eNOS hyperactivation in ISCLS-derived ECs. Our findings provide mechanistic insights into microvascular barrier dysfunction in ISCLS and highlight a potential therapeutic approach.

Nitric oxide, endothelium-derived hyperpolarizing factor, and smooth muscle-dependent mechanisms contribute to magnesium-dependent vascular relaxation in mouse arteries

AIM

Magnesium (Mg2+ ) is a vasorelaxant. The underlying physiological mechanisms driving this vasorelaxation remain unclear. Studies were designed to test the hypothesis that multiple signaling pathways including nitric oxide (NO) and endothelium-derived hyperpolarizing factor (EDHF) in endothelial cells as well as Ca2+ antagonization and TRPM7 channels in vascular smooth muscle cells mediate Mg2+ -dependent vessel relaxation.

METHODS

To uncover these mechanisms, force development was measured ex vivo in aorta rings from mice using isometric wire myography. Concentration responses to Mg2+ were studied in intact and endothelium-denuded aortas. Key findings were confirmed in second-order mesenteric resistance arteries perfused ex vivo using pressure myography. Effects of Mg2+ on NO formation were measured in Chinese Hamster Ovary (CHO) cells, isolated mesenteric vessels, and mouse urine.

RESULTS

Mg2+ caused a significant concentration-dependent relaxation of aorta rings. This relaxation was attenuated significantly in endothelium-denuded aortas. The endothelium-dependent portion was inhibited by NO and cGMP blockade but not by cyclooxygenase inhibition. Mg2+ stimulated local NO formation in CHO cells and isolated mesenteric vessels without changing urinary NOx levels. High extracellular Mg2+ augmented acetylcholine-induced relaxation. SKCa and IKCa channel blockers apamin and TRAM34 inhibited Mg2+ -dependent relaxation. The endothelium-independent relaxation in aorta rings was inhibited by high extracellular Ca2+ . Combined blockade of NO, SKCa , and IKCa channels significantly reduced Mg2+ -dependent dilatation in mesenteric resistance vessels.

CONCLUSIONS

In mouse conductance and resistance arteries Mg2+ -induced relaxation is contributed by endothelial NO formation, EDHF pathways, antagonism of Ca2+ in smooth muscle cells, and additional unidentified mechanisms.

Magnesium promotes vascularization and osseointegration in diabetic states

Diabetes has long been considered a risk factor in implant therapy and impaired wound healing in soft and hard oral tissues. Magnesium has been proved to promote bone healing under normal conditions. Here, we elucidate the mechanism by which Mg2+ promotes angiogenesis and osseointegration in diabetic status. We generated a diabetic mice model and demonstrated the alveolar bone healing was compromised, with significantly decreased angiogenesis. We then developed Mg-coating implants with hydrothermal synthesis. These implants successfully improved the vascularization and osseointegration in diabetic status. Mechanically, Mg2+ promoted the degradation of Kelch-like ECH-associated protein 1 (Keap1) and the nucleation of nuclear factor erythroid 2-related factor 2 (Nrf2) by up-regulating the expression of sestrin 2 (SESN2) in endothelial cells, thus reducing the elevated levels of oxidative stress in mitochondria and relieving endothelial cell dysfunction under hyperglycemia. Altogether, our data suggested that Mg2+ promoted angiogenesis and osseointegration in diabetic mice by regulating endothelial mitochondrial metabolism.

Associations between Serum Mineral Nutrients, Gut Microbiota, and Risk of Neurological, Psychiatric, and Metabolic Diseases: A Comprehensive Mendelian Randomization Study

Recent observational studies have reported associations between serum mineral nutrient levels, gut microbiota composition, and neurological, psychiatric, and metabolic diseases. However, the causal effects of mineral nutrients on gut microbiota and their causal associations with diseases remain unclear and require further investigation. This study aimed to identify the associations between serum mineral nutrients, gut microbiota, and risk of neurological, psychiatric, and metabolic diseases using Mendelian randomization (MR). We conducted an MR study using the large-scale genome-wide association study (GWAS) summary statistics of 5 serum mineral nutrients, 196 gut microbes at the phylum, order, family, and genus levels, and a variety of common neurological, psychiatric, and metabolic diseases. Initially, the independent causal associations of mineral nutrients and gut microbiota with diseases were examined by MR. Subsequently, the causal effect of mineral nutrients on gut microbiota was estimated to investigate whether specific gut microbes mediated the association between mineral nutrients and diseases. Finally, we performed sensitivity analyses to assess the robustness of the study results. After correcting for multiple testing, we identified a total of 33 causal relationships among mineral nutrients, gut microbiota, and diseases. Specifically, we found 4 causal relationships between 3 mineral nutrition traits and 3 disease traits, 15 causal associations between 14 gut microbiota traits and 6 disease traits, and 14 causal associations involving 4 mineral nutrition traits and 15 gut microbiota traits. Meanwhile, 118 suggestive associations were identified. The current study reveals multiple causal associations between serum mineral nutrients, gut microbiota, risk of neurological, psychiatric, and metabolic diseases, and potentially provides valuable insights for subsequent nutritional therapies.

The development of magnesium-based biomaterials in bone tissue engineering: A review

Bone regeneration is a vital clinical challenge in massive or complicated bone defects. Recently, bone tissue engineering has come to the fore to meet the demand for bone repair with various innovative materials. However, the reported materials usually cannot satisfy the requirements, such as ideal mechanical and osteogenic properties, as well as biocompatibility at the same time. Mg-based biomaterials have considerable potential in bone tissue engineering owing to their excellent mechanical strength and biosafety. Moreover, the biocompatibility and osteogenic activity of Mg-based biomaterials have been the research focuses in recent years. The main limitation faced in the applications of Mg-based biomaterials is rapid degradation, which can produce excessive Mg2+ and hydrogen, affecting the healing of the bone defect. In order to overcome the limitations, researchers have explored several ways to improve the properties of Mg-based biomaterials, including alloying, surface modification with coatings, and synthesizing other composite materials to control the degradation rate upon implantation. This article reviewed the osteogenic mechanism and requirement for appropriate degradation rate and focused on current progress in the biomedical use of Mg-based biomaterials to inspire more clinical applications of Mg in bone regeneration in the future.

Nanosized Silk-Magnesium Complexes for Tissue Regeneration

Metal ions provide multifunctional signals for cell and tissue functions, including regeneration. Inspired by metal-organic frameworks (MOFs), nanosized silk protein aggregates with a high negative charge density are used to form stable silk-magnesium ion complexes. Magnesium ions (Mg ions) are added directly to silk nanoparticle solutions, inducing gelation through the formation of silk-Mg coordination complexes. The Mg ions are released slowly from the nanoparticles through diffusion, with sustained release via tuning the degradation or dissolution of the nanosized silk aggregates. Studies in vitro reveal a dose-dependent influence of Mg ions on angiogenic and anti-inflammatory functions. Silk-Mg ion complexes in the form of hydrogels also stimulate tissue regeneration with a reduced formation of scar tissue in vivo, suggesting potential utility in tissue regeneration.

The effect of magnesium sulfate on gene expression and serum level of inflammatory cytokines in coronary artery disease patients

PURPOSE

To evaluate the effect of oral magnesium sulfate (MgSO4) on the gene expression and serum levels of inflammatory cytokines including TNF-α, IL-18, IL-1β, IL-6, and IFN-γ in patients with moderate coronary artery disease (CAD).

METHODS

60 CAD patients were selected based on angiography findings and were randomly divided into two groups that received 300 mg/day MgSO4 (n = 30) or placebo (n = 30) for 3 months. Gene expression and serum levels of inflammatory cytokines were assessed.

RESULTS

After 3 months of intervention, gene expression and serum levels of IL-18 and TNF-α in the MgSO4 group were significantly less than the placebo group (P < 0.05). However, no significant difference in gene expression and serum levels of IL-1β, IL-6, and IFN-γ was observed between the two groups (P > 0.05). In addition, within group analysis demonstrate that Mg-treatment significantly decrease serum level of TNF-α and IL-18 as compared to pretreatment.

CONCLUSION

The results of our study demonstrate that 3-month magnesium sulfate administration (300 mg/day) to CAD patients could significantly decrease serum concentration and gene expression levels of IL-18 and TNF-α. Our findings support the potential beneficial effect of magnesium supplementation on alleviating CAD complications through modulating inflammatory cytokines.

Beyond Ion Homeostasis: Hypomagnesemia, Transient Receptor Potential Melastatin Channel 7, Mitochondrial Function, and Inflammation

As the second most abundant intracellular divalent cation, magnesium (Mg2+) is essential for cell functions, such as ATP production, protein/DNA synthesis, protein activity, and mitochondrial function. Mg2+ plays a critical role in heart rhythm, muscle contraction, and blood pressure. A significant decline in Mg2+ intake has been reported in developed countries because of the increased consumption of processed food and filtered/deionized water, which can lead to hypomagnesemia (HypoMg). HypoMg is commonly observed in cardiovascular diseases, such as heart failure, hypertension, arrhythmias, and diabetic cardiomyopathy, and HypoMg is a predictor for cardiovascular and all-cause mortality. On the other hand, Mg2+ supplementation has shown significant therapeutic effects in cardiovascular diseases. Some of the effects of HypoMg have been ascribed to changes in Mg2+ participation in enzyme activity, ATP stabilization, enzyme kinetics, and alterations in Ca2+, Na+, and other cations. In this manuscript, we discuss new insights into the pathogenic mechanisms of HypoMg that surpass previously described effects. HypoMg causes mitochondrial dysfunction, oxidative stress, and inflammation. Many of these effects can be attributed to the HypoMg-induced upregulation of a Mg2+ transporter transient receptor potential melastatin 7 channel (TRMP7) that is also a kinase. An increase in kinase signaling mediated by HypoMg-induced TRPM7 transcriptional upregulation, independently of any change in Mg2+ transport function, likely seems responsible for many of the effects of HypoMg. Therefore, Mg2+ supplementation and TRPM7 kinase inhibition may work to treat the sequelae of HypoMg by preventing increased TRPM7 kinase activity rather than just altering ion homeostasis. Since many diseases are characterized by oxidative stress or inflammation, Mg2+ supplementation and TRPM7 kinase inhibition may have wider implications for other diseases by acting to reduce oxidative stress and inflammation.

Intracellular Mg2+ protects mitochondria from oxidative stress in human keratinocytes

Reactive oxygen species (ROS) are harmful for the human body, and exposure to ultraviolet irradiation triggers ROS generation. Previous studies have demonstrated that ROS decrease mitochondrial membrane potential (MMP) and that Mg2+ protects mitochondria from oxidative stress. Therefore, we visualized the spatio-temporal dynamics of Mg2+ in keratinocytes (a skin component) in response to H2O2 (a type of ROS) and found that it increased cytosolic Mg2+ levels. H2O2-induced responses in both Mg2+ and ATP were larger in keratinocytes derived from adults than in keratinocytes derived from newborns, and inhibition of mitochondrial ATP synthesis enhanced the H2O2-induced Mg2+ response, indicating that a major source of Mg2+ was dissociation from ATP. Simultaneous imaging of Mg2+ and MMP revealed that larger Mg2+ responses corresponded to lower decreases in MMP in response to H2O2. Moreover, Mg2+ supplementation attenuated H2O2-induced cell death. These suggest the potential of Mg2+ as an active ingredient to protect skin from oxidative stress.

The Role of Txnip in Mediating Low-Magnesium-Driven Endothelial Dysfunction

Magnesium deficiency is associated with a greater risk of developing cardiovascular diseases since this cation is fundamental in regulating vascular function. This clinical evidence is sustained by in vitro studies showing that culturing endothelial cells in low concentrations of magnesium promotes the acquisition of a pro-oxidant and pro-inflammatory phenotype. Here, we show that the increase in reactive oxygen species in endothelial cells in low-magnesium-containing medium is due to the upregulation of the pro-oxidant protein thioredoxin interacting protein (TXNIP), with a consequent accumulation of lipid droplets and increase in endothelial permeability through the downregulation and relocalization of junctional proteins. Silencing TXNIP restores the endothelial barrier and lipid content. Because (i) mitochondria serve multiple roles in shaping cell function, health and survival and (ii) mitochondria are the main intracellular stores of magnesium, it is of note that no significant alterations were detected in their morphology and dynamics in our experimental model. We conclude that TXNIP upregulation contributes to low-magnesium-induced endothelial dysfunction in vitro.

The TRPM7 channel reprograms cellular glycolysis to drive tumorigenesis and angiogenesis

Cancer or endothelial cells preferably catabolize glucose through aerobic glycolysis rather than oxidative phosphorylation. Intracellular ionic signaling has been shown to regulate glucose metabolism, but the underlying ion channel has yet to be identified. RNA-seq, metabolomics and genetic assay revealed that the TRPM7 channel regulated cellular glycolysis. Deletion of TRPM7 suppressed cancer cell glycolysis and reduced the xenograft tumor burden. Deficiency of endothelial TRPM7 inhibited postnatal retinal angiogenesis in mice. Mechanistically, TRPM7 transcriptionally regulated the solute carrier family 2 member 3 (SLC2A3, also known as GLUT3) via Ca²⁺ influx-induced calcineurin activation. Furthermore, CREB-regulated transcription coactivator 2 (CRTC2) and CREB act downstream of calcineurin to relay Ca²⁺ signal to SLC2A3 transcription. Expression of the constitutively active CRTC2 or CREB in TRPM7 knockout cell normalized glycolytic metabolism and cell growth. The TRPM7 channel represents a novel regulator of glycolytic reprogramming. Inhibition of the TRPM7-dependent glycolysis could be harnessed for cancer therapy.

Stimulus-Responsive Zwitterionic Prodrug Delivery System with Sustained Release of Hydrogen Sulfide for Protective Aortic Dissection

Aortic dissection (AD) is one of the most frequent types of aortic disease with extremely poor prognosis. The biological signaling gas hydrogen sulfide (H2S) has exhibited protective effects in various types of cardiovascular diseases. However, as a toxic, colorless gas, the application of H2S is immensely hampered due to the lack of ideal donors. In this article, a drug delivery system with a H2S donor has been prepared. Meanwhile, the donor could be deposed in a cysteine-containing environment to generate H2S. The results indicate that the H2S donor polymer nanomicelles mitigated the processive transformation of smooth muscle cells effectively in a proper concentration range, which may play a protective role in aortic dissection. In animal experiments, the sustained-release H2S donor stimulated in the presence of cysteine was found to demonstrate beneficial effects in a murine model of aortic dissection and would likely become a potential target of H2S therapy for cardiovascular diseases.

Cardiovascular toxicity of tyrosine kinase inhibitors during cancer treatment: Potential involvement of TRPM7

Receptor tyrosine kinases (RTKs) are a class of membrane spanning cell-surface receptors that transmit extracellular signals through the membrane to trigger diverse intracellular signaling through tyrosine kinases (TKs), and play important role in cancer development. Therapeutic approaches targeting RTKs such as vascular endothelial growth factor receptor (VEGFR), epidermal growth factor receptor (EGFR), and platelet-derived growth factor receptor (PDGFR), and TKs, such as c-Src, ABL, JAK, are widely used to treat human cancers. Despite favorable benefits in cancer treatment that prolong survival, these tyrosine kinase inhibitors (TKIs) and monoclonal antibodies targeting RTKs are also accompanied by adverse effects, including cardiovascular toxicity. Mechanisms underlying TKI-induced cardiovascular toxicity remain unclear. The transient receptor potential melastatin-subfamily member 7 (TRPM7) is a ubiquitously expressed chanzyme consisting of a membrane-based ion channel and intracellular α-kinase. TRPM7 is a cation channel that regulates transmembrane Mg²⁺ and Ca²⁺ and is involved in a variety of (patho)physiological processes in the cardiovascular system, contributing to hypertension, cardiac fibrosis, inflammation, and atrial arrhythmias. Of importance, we and others demonstrated significant cross-talk between TRPM7, RTKs, and TK signaling in different cell types including vascular smooth muscle cells (VSMCs), which might be a link between TKIs and their cardiovascular effects. In this review, we summarize the implications of RTK inhibitors (RTKIs) and TKIs in cardiovascular toxicities during anti-cancer treatment, with a focus on the potential role of TRPM7/Mg²⁺ as a mediator of RTKI/TKI-induced cardiovascular toxicity. We also describe the important role of TRPM7 in cancer development and cardiovascular diseases, and the interaction between TRPM7 and RTKs, providing insights for possible mechanisms underlying cardiovascular disease in cancer patients treated with RTKI/TKIs.

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.

Mg-based materials diminish tumor spreading and cancer metastases

Cancer metastases are the most common causes of cancer-related deaths. The formation of secondary tumors at different sites in the human body can impair multiple organ function and dramatically decrease the survival of the patients. In this stage, it is difficulty to treat tumor growth and spreading due to arising therapy resistances. Therefore, it is important to prevent cancer metastases and to increase subsequent cancer therapy success. Cancer metastases are conventionally treated with radiation or chemotherapy. However, these treatments elicit lots of side effects, wherefore novel local treatment approaches are currently discussed. Recent studies already showed anticancer activity of specially designed degradable magnesium (Mg) alloys by reducing the cancer cell proliferation. In this work, we investigated the impact of these Mg-based materials on different steps of the metastatic cascade including cancer cell migration, invasion, and cancer-induced angiogenesis. Both, Mg and Mg–6Ag reduced cell migration and invasion of osteosarcoma cells in coculture with fibroblasts. Furthermore, the Mg-based materials used in this study diminished the cancer-induced angiogenesis. Endothelial cells incubated with conditioned media obtained from these Mg and Mg–6Ag showed a reduced cell layer permeability, a reduced proliferation and inhibited cell migration. The tube formation as a last step of angiogenesis was stimulated with the presence of Mg under normoxia and diminished under hypoxia.

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Magnesium (Mg)-based material degradation decrease cell migration and invasion of an osteosarcoma coculture.

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Mg-based material degradation products reduce cancer-induced angiogenesis at an early stage.

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These materials may reduce secondary tumor formation and metastases.

Biosynthesized Bandages Carrying Magnesium Oxide Nanoparticles Induce Cortical Bone Formation by Modulating Endogenous Periosteal Cells

Bone grafting is frequently conducted to treat bone defects caused by trauma and tumor removal, yet with significant medical and socioeconomic burdens. Space-occupying bone substitutes remain challenging in the control of osteointegration, and meanwhile activation of endogenous periosteal cells by using non-space-occupying implants to promote new bone formation becomes another therapeutic strategy. Here, we fabricated a magnesium-based artificial bandage with optimal micropatterns for activating periosteum-associated biomineralization. Collagen was self-assembled on the surface of magnesium oxide nanoparticles embedded electrospun fibrous membranes as a hierarchical bandage structure to facilitate the integration with periosteum in situ. After the implantation on the surface of cortical bone in vivo, magnesium ions were released to generate a pro-osteogenic immune microenvironment by activating the endogenous periosteal macrophages into M2 phenotype and, meanwhile, promote blood vessel formation and neurite outgrowth. In a cortical bone defect model, magnesium-based artificial bandage guided the surrounding newly formed bone tissue to cover the defected area. Taken together, our study suggests that the strategy of stimulating bone formation can be achieved with magnesium delivery to periosteum in situ and the proposed periosteal bandages act as a bioactive media for accelerating bone healing.

Hypomagnesemia and Cardiovascular Risk in Type 2 Diabetes

Hypomagnesemia is tenfold more common in individuals with type 2 diabetes (T2D), compared to the healthy population. Factors that are involved in this high prevalence are low Mg2+ intake, gut microbiome composition, medication use and presumably genetics. Hypomagnesemia is associated with insulin resistance, which subsequently increases the risk to develop T2D or deteriorates glycaemic control in existing diabetes. Mg2+ supplementation decreases T2D associated features like dyslipidaemia and inflammation; which are important risk factors for cardiovascular disease (CVD). Epidemiological studies have shown an inverse association between serum Mg2+ and the risk to develop heart failure (HF), atrial fibrillation (AF) and microvascular disease in T2D. The potential protective effect of Mg2+ on HF and AF may be explained by reduced oxidative stress, fibrosis and electrical remodeling in the heart. In microvascular disease, Mg2+ reduces the detrimental effects of hyperglycemia and improves endothelial dysfunction. Though, clinical studies assessing the effect of long-term Mg2+ supplementation on CVD incidents are lacking and gaps remain on how Mg2+ may reduce CVD risk in T2D. Despite the high prevalence of hypomagnesemia in people with T2D, routine screening of Mg2+ deficiency to provide Mg2+ supplementation when needed is not implemented in clinical care as sufficient clinical evidence is lacking. In conclusion, hypomagnesemia is common in people with T2D and is both involved as cause, probably through molecular mechanisms leading to insulin resistance, and consequence and is prospectively associated with development of HF, AF and microvascular complications. Whether long-term supplementation of Mg2+ is beneficial, however, remains to be determined.

Controlled magnesium ion delivery system for in situ bone tissue engineering

Magnesium cation (Mg²⁺) has been an emerging therapeutic agent for inducing vascularized bone regeneration. However, the therapeutic effects of current magnesium (Mg) -containing biomaterials are controversial due to the concentration- and stage-dependent behavior of Mg²⁺. Here, we first provide an overview of biochemical mechanism of Mg²⁺ in various concentrations and suggest that 2-10 mM Mg²⁺in vitro may be optimized. This review systematically summarizes and discusses several types of controlled Mg²⁺ delivery systems based on polymer-Mg composite scaffolds and Mg-containing hydrogels, as well as their design philosophy and several parameters that regulate Mg²⁺ release. Given that the continuous supply of Mg²⁺ may prevent biomineral deposition in the later stage of bone regeneration and maturation, we highlight the controlled delivery of Mg²⁺ based dual- or multi-ions system, especially for the hierarchical therapeutic ion release system, which shows enhanced biomineralization. Finally, the remaining challenges and perspectives of Mg-containing biomaterials for future in situ bone tissue engineering are discussed as well.

1-L Transcription in Alzheimer's Disease

Alzheimer’s disease is a very complex disease and better explanations and models are needed to understand how neurons are affected and microglia are activated. A new model of Alzheimer’s disease is presented here, the β-amyloid peptide is considered an important RNA recognition/binding peptide. 1-L transcription revealed compatible sequences with AAUAAA (PAS signal) and UUUC (class III ARE rich in U) in the Aβ peptide, supporting the peptide–RNA regulatory model. When a hypothetical model of fibril selection with the prionic character of amyloid assemblies is added to the peptide-RNA regulatory model, the downregulation of the PI3K-Akt pathway and the upregulation of the PLC-IP3 pathway are well explained. The model explains why neurons are less protected from inflammation and why microglia are activated; why mitochondria are destabilized; why the autophagic flux is destabilized; and why the post-transcriptional attenuation of the axonal signal “noise” is interrupted. For example, the model suggests that Aβ peptide may post-transcriptionally control ELAVL2 (ELAV-like RNA binding protein 2) and DCP2 (decapping mRNA protein 2), which are known to regulate RNA processing, transport, and stability.

Modulatory effect of two regimens of magnesium sulfate on the systemic inflammatory response in pregnant women with imminent eclampsia

OBJECTIVE

This study compared the modulatory effect of two intravenous magnesium sulfate (MgSO₄) regimens on the systemic inflammatory response in pregnant women diagnosed with imminent eclampsia.

STUDY DESIGN

In a single-blind cross-sectional study, 33 women were allocated according to the Zuspan (n = 16) and Sibai (n = 17) MgSO₄ regimens, and treated for 24 h. Blood samples were collected pre-administration of the loading dose, at 24 h of the maintenance dose of MgSO₄, and at 48 h, when patients were without treatment. Plasma was used to determine interleukin (IL)-1 beta (IL-1β), IL-6, IL-10, tumor necrosis factor-alpha (TNF-α), heat shock protein (Hsp70), and heme oxygenase-1 (HO-1) by ELISA.

RESULTS

The treatment with the Zuspan's regimen didn't change plasma concentrations of TNF-α, IL-10, and Hsp70 in the three-time points studied. However, it decreased IL-1β at 24 h and 48 h and IL-6 at 48 h, and increased HO-1 concentration at 48 h. On the other hand, compared to the pre-treatment period, Sibai's regimen induced a significant decrease in TNF-α, IL-1β, IL-6, and Hsp70, while increased HO-1 levels both at 24 h and 48 h and, IL-10 concentration at 48 h.

CONCLUSIONS

Sibai's regimen determined an early and efficient immunoregulatory effect on systemic inflammatory response in preeclampsia, suggesting that the maintenance dose of two grams of MgSO₄ was better than one gram in the treatment of imminent eclampsia.

Dissociation of nanosilicates induces downstream endochondral differentiation gene expression program

Bioactive materials harness the body's innate regenerative potential by directing endogenous progenitor cells to facilitate tissue repair. Dissolution products of inorganic biomaterials provide unique biomolecular signaling for tissue-specific differentiation. Inorganic ions (minerals) are vital to biological processes and play crucial roles in regulating gene expression patterns and directing cellular fate. However, mechanisms by which ionic dissolution products affect cellular differentiation are not well characterized. We demonstrate the role of the inorganic biomaterial synthetic two-dimensional nanosilicates and its ionic dissolution products on human mesenchymal stem cell differentiation. We use whole-transcriptome sequencing (RNA-sequencing) to characterize the contribution of nanosilicates and its ionic dissolution products on endochondral differentiation. Our study highlights the modulatory role of ions in stem cell transcriptome dynamics by regulating lineage-specific gene expression patterns. This work paves the way for leveraging biochemical characteristics of inorganic biomaterials to direct cellular processes and promote in situ tissue regeneration.

Low Serum Magnesium Levels Are Associated With Hemorrhagic Transformation After Mechanical Thrombectomy in Patients With Acute Ischemic Stroke

Objective

In patients with acute ischemic stroke (AIS), hemorrhagic transformation (HT) is a major complication after mechanical thrombectomy (MT). This study aimed to investigate the relationship between serum magnesium levels and HT after MT.

Methods

We collected 199 cases of consecutive AIS that received MT due to acute anterior circulation occlusions in our institution between January 2017 and January 2020. Baseline serum magnesium was obtained from all patients on admission before MT. The patients were divided into two groups based on the occurrence of HT. Univariate and multivariate analyses were performed to investigate whether magnesium was an independent predictor of HT. The receiver operating characteristic (ROC) curve and area under the curve (AUC) were determined.

Results

Of the 199 enrolled patients, 40 (20.1%) presented with HT, and 12 (6%) developed symptomatic intracranial hemorrhage (sICH). Patients with HT had lower serum magnesium levels compared to those without HT (0.76 [0.69–0.80] vs. 0.84 [0.80–0.90], p < 0.001). The multivariate logistic analysis showed that the serum magnesium level (odds ratio, [OR]: 0.000, 95% confidence interval [CI]: 0.000–0.001, p < 0.001) was significantly associated with the occurrence of HT. The ROC curve analysis revealed that the serum magnesium level could predict HT with an AUC of.820 (95% CI: 0.750–0.891 p < 0.001). Serum magnesium ≤ 0.80 mmol/L could predict HT with a sensitivity of 79.2% and a specificity of 70.0%. Of interest, the serum magnesium level was not associated with HT when the baseline of serum magnesium was higher than the cut-off value (0.80 mmol/L) in the subgroup analysis.

Conclusions

Lower baseline serum magnesium levels (<0.80 mmol/L) on admission are associated with increased risk of HT in AIS patients receiving MT.

mTORC1 induces plasma membrane depolarization and promotes preosteoblast senescence by regulating the sodium channel Scn1a

Senescence impairs preosteoblast expansion and differentiation into functional osteoblasts, blunts their responses to bone formation-stimulating factors and stimulates their secretion of osteoclast-activating factors. Due to these adverse effects, preosteoblast senescence is a crucial target for the treatment of age-related bone loss; however, the underlying mechanism remains unclear. We found that mTORC1 accelerated preosteoblast senescence in vitro and in a mouse model. Mechanistically, mTORC1 induced a change in the membrane potential from polarization to depolarization, thus promoting cell senescence by increasing Ca²⁺ influx and activating downstream NFAT/ATF3/p53 signaling. We further identified the sodium channel Scn1a as a mediator of membrane depolarization in senescent preosteoblasts. Scn1a expression was found to be positively regulated by mTORC1 upstream of C/EBPα, whereas its permeability to Na⁺ was found to be gated by protein kinase A (PKA)-induced phosphorylation. Prosenescent stresses increased the permeability of Scn1a to Na⁺ by suppressing PKA activity and induced depolarization in preosteoblasts. Together, our findings identify a novel pathway involving mTORC1, Scn1a expression and gating, plasma membrane depolarization, increased Ca²⁺ influx and NFAT/ATF3/p53 signaling in the regulation of preosteoblast senescence. Pharmaceutical studies of the related pathways and agents might lead to novel potential treatments for age-related bone loss.

Materials and Interface Designs of Waterproof Field-Effect Transistor Arrays for Detection of Neurological Biomarkers

The continuous, real-time, and concurrent detection of multiple biomarkers in bodily fluids is of high significance for advanced healthcare. While active, semiconductor-based biochemical sensing platforms provide levels of functionality exceeding those of their conventional passive counterparts, the stability of the active biosensors in the liquid environment for continuous operation remains a challenging topic. This work reports the development of a class of flexible and waterproof field-effect transistor arrays for multiplexed biochemical sensing. In this design, monolithic, ultrathin, dense, and low defect nanomembranes consisting of monocrystalline Si and thermally grown SiO₂ simultaneously serve as high-performance backplane electronics for signal transduction and stable biofluid barriers with high structural integrity due to the high formation temperature. Coupling the waterproof transistors with various ion-selective membranes through the gate electrode allows for sensitive and selective detection of multiple ions as biomarkers for traumatic brain injury. The study also demonstrates a similar encapsulation structure which enables the design of waterproof amperometric sensors based on this materials strategy and integration scheme. Overall, key advantages in flexibility, stability, and multifunctionality highlight the potential of using such electronic sensing platforms for concurrent, continuous detection of various neurological biomarkers, proving a promising approach for early diagnosis and intervention of chronic diseases.

A Review of Risk Factors and Predictors for Hemorrhagic Transformation in Patients with Acute Ischemic Stroke

Acute ischemic strokes (AIS) and hemorrhagic strokes lead to disabling neuropsychiatric and cognitive deficits. A serious and fatal complication of AIS is the occurrence of hemorrhagic transformation (HT). HT is cerebral bleeding that occurs after an ischemic event in the infarcted areas. This review summarises how specific risk factors such as demographic factors like age, gender, and race/ethnicity, comorbidities including essential hypertension, atrial fibrillation, diabetes mellitus, congestive heart failure, and ischemic heart disease along with predictors like higher NIHSS score, larger infarction size, cardioembolic strokes, systolic blood pressure/pulse pressure variability, higher plasma glucose levels, and higher body temperature during ischemic event, lower low-density lipoprotein and total cholesterol, early ischemic changes on imaging modalities, and some rare causes make an individual more susceptible to developing HT. We also discuss few other risk factors such as the role of blood-brain barrier, increased arterial stiffness, and globulin levels in patients postreperfusion using thrombolysis and mechanical thrombectomy. In addition, we discuss the implications of dual antiplatelet therapy and the length of treatment in reference to the incidence of developing HT. Current research into inflammatory mediators and biomarkers such as Cyclooxygenase-2, matrix metalloproteinases, and soluble ST2 and their potential role as treatment options for HT is also briefly discussed. Finally, this review calls for more research into use of dual antiplatelet and the timing of antiplatelet and anticoagulant use in reference to hemorrhagic transformation.

Engineering a 3D human intracranial aneurysm model using liquid-assisted injection molding and tuned hydrogels

Physiologically relevant intracranial aneurysm (IA) models are crucially required to facilitate testing treatment options for IA. Herein, we report the development of a new in vitro tissue-engineered platform, which recapitulates the microenvironment, structure, and cellular complexity of native human IA. A new modified liquid-assisted injection molding technique was developed to fabricate a three-dimensional hollow IA model with clinically relevant IA dimensions within a mechanically tuned Gelatin Methacryloyl (GelMA) hydrogel. An endothelium lining was created inside the IA model by culturing human umbilical vein endothelial cells over pre-cultured human brain vascular smooth muscle cells. These cellularized IA models were subjected to medium perfusion at flow rates between 6.3 and 15.75 mL/min for inducing biomimetic vessel wall shear stress (10-25 dyn/cm²) to the cells for ten days. Both cell types maintained their secretome profiles and showed more than 96% viability, demonstrating the biocompatibility of the hydrogel during perfusion cell culture at such flow rates. Based on the characterized viscoelastic properties of the GelMA hydrogel and with the aid of a fluid-structure interaction model, the capability of the IA model in predicting the response of the IA to different fluid flow profiles was mathematically shown. With physiologically relevant behavior, our developed in vitro human IA model could allow researchers to better understand the pathophysiology and treatment of IA. STATEMENT OF SIGNIFICANCE: A three-dimensional intracranial aneurysm (IA) tissue model recapitulating the microenvironment, structure, and cellular complexity of native human IA was developed. • An endothelium lining was created inside the IA model over pre-cultured human brain vascular smooth muscle cells over at least 10-day successful culture. • The cells maintained their secretome profiles, demonstrating the biocompatibility of hydrogel during a long-term perfusion cell culture. • The IA model showed its capability in predicting the response of IA to different fluid flow profiles. • The cells in the vessel region behaved differently from cells in the aneurysm region due to alteration in hemodynamic shear stress. • The IA model could allow researchers to better understand the pathophysiology and treatment options of IA.

Potential Implications of Mammalian Transient Receptor Potential Melastatin 7 in the Pathophysiology of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Review

The transient receptor potential (TRP) superfamily of ion channels is involved in the molecular mechanisms that mediate neuroimmune interactions and activities. Recent advancements in neuroimmunology have identified a role for TRP cation channels in several neuroimmune disorders including amyotropic lateral sclerosis, multiple sclerosis, and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). ME/CFS is a debilitating disorder with an obscure aetiology, hence considerable examination of its pathobiology is warranted. Dysregulation of TRP melastatin (TRPM) subfamily members and calcium signalling processes are implicated in the neurological, immunological, cardiovascular, and metabolic impairments inherent in ME/CFS. In this review, we present TRPM7 as a potential candidate in the pathomechanism of ME/CFS, as TRPM7 is increasingly recognized as a key mediator of physiological and pathophysiological mechanisms affecting neurological, immunological, cardiovascular, and metabolic processes. A focused examination of the biochemistry of TRPM7, the role of this protein in the aforementioned systems, and the potential of TRPM7 as a molecular mechanism in the pathophysiology of ME/CFS will be discussed in this review. TRPM7 is a compelling candidate to examine in the pathobiology of ME/CFS as TRPM7 fulfils several key roles in multiple organ systems, and there is a paucity of literature reporting on its role in ME/CFS.

Cytoskeletal Remodeling Mimics Endothelial Response to Microgravity

Mechanical cues contribute to the maintenance of a healthy endothelium, which is essential for vascular integrity. Indeed endothelial cells are mechanosensors that integrate the forces in the form of biochemical signals. The cytoskeleton is fundamental in sensing mechanical stimuli and activating specific signaling pathways. Because the cytoskeleton is very rapidly remodeled in endothelial cells exposed to microgravity, we investigated whether the disruption of actin polymerization by cytochalasin D in 1g condition triggers and orchestrates responses similar to those occurring in micro- and macro-vascular endothelial cells upon gravitational unloading. We focused our attention on the effect of simulated microgravity on stress proteins and transient receptor potential melastatin 7 (TRPM7), a cation channel that acts as a mechanosensor and modulates endothelial cell proliferation and stress response. Simulated microgravity downregulates TRPM7 in both cell types. However, 24 h of treatment with cytochalasin D decreases the amounts of TRPM7 only in macrovascular endothelial cells, suggesting that the regulation and the role of TRPM7 in microvascular cells are more complex than expected. The 24 h culture in the presence of cytochalasin D mimics the effect of simulated microgravity in modulating stress response in micro- and macro-vascular endothelial cells. We conclude that cytoskeletal disruption might mediate some effects of microgravity in endothelial cells.

The biological responses and mechanisms of endothelial cells to magnesium alloy

Due to its good biocompatibility and degradability, magnesium alloy (Mg alloy) has shown great promise in cardiovascular stent applications. Rapid stent re-endothelialization is derived from migrated and adhered endothelial cells (ECs), which is an effective way to reduce late thrombosis and inhibit hyperplasia. However, fundamental questions regarding Mg alloy affecting migration and adhesion of ECs are not fully understood. Here, we evaluated the effects of Mg alloy on the ECs proliferation, adhesion and migration. A global gene expression profiling of ECs co-culturing with Mg alloy was conducted, and the adhesion- and migration-related genes were examined. We found that Mg alloy had no adverse effects on ECs viability but significantly affected ECs migration and adhesion. Co-cultured with Mg alloy extract, ECs showed contractive adhesion morphology and decreased motility, which was supported by the down-regulation of adhesion-related genes (Paxillin and Vinculin) and migration-related genes (RAC 1, Rho A and CDC 42). Accordingly, the re-endothelialization of Mg alloy stent was inhibited in vivo. Our results may provide new inspiration for improving the broad application of Mg alloy stents.

Low Dietary Magnesium and Overweight/Obesity in a Mediterranean Population: A Detrimental Synergy for the Development of Hypertension. The SUN Project

Hypertension is the strongest independent modifiable risk factor for cardiovascular disease. We aimed to investigate the association of magnesium intake with incident hypertension in a Mediterranean population, and the potential modification of this association by body mass index BMI. We assessed 14,057 participants of the SUN (Seguimiento Universidad de Navarra) prospective cohort (67.0% women) initially free of hypertension. At baseline, a validated 136-item food frequency questionnaire was administered. We used Cox models adjusted for multiple socio-demographic, anthropometric, and lifestyle factors, and prevalent conditions present at baseline. Among a mean 9.6 years of follow-up we observed 1406 incident cases of medically diagnosed hypertension. An inverse association in multivariable-adjusted models was observed for progressively higher magnesium intake up to 500 mg/d vs. intake < 200 mg/d, which was greater among those with a BMI > 27 kg/m². Lean participants with magnesium intake < 200 mg/d vs. >200 mg/d also had a higher risk of incident hypertension. Adherence to the Mediterranean diet did not modify these associations. In conclusion, dietary magnesium intake < 200 mg/d was independently associated with a higher risk of developing hypertension in a Mediterranean cohort, stronger for overweight/obese participants. Our results emphasize the importance of encouraging the consumption of magnesium-rich foods (vegetables, nuts, whole cereals, legumes) in order to prevent hypertension.

TRP Channels Regulation of Rho GTPases in Brain Context and Diseases

Neurological and neuropsychiatric disorders are mediated by several pathophysiological mechanisms, including developmental and degenerative abnormalities caused primarily by disturbances in cell migration, structural plasticity of the synapse, and blood-vessel barrier function. In this context, critical pathways involved in the pathogenesis of these diseases are related to structural, scaffolding, and enzymatic activity-bearing proteins, which participate in Ca²⁺- and Ras Homologs (Rho) GTPases-mediated signaling. Rho GTPases are GDP/GTP binding proteins that regulate the cytoskeletal structure, cellular protrusion, and migration. These proteins cycle between GTP-bound (active) and GDP-bound (inactive) states due to their intrinsic GTPase activity and their dynamic regulation by GEFs, GAPs, and GDIs. One of the most important upstream inputs that modulate Rho GTPases activity is Ca²⁺ signaling, positioning ion channels as pivotal molecular entities for Rho GTPases regulation. Multiple non-selective cationic channels belonging to the Transient Receptor Potential (TRP) family participate in cytoskeletal-dependent processes through Ca²⁺-mediated modulation of Rho GTPases. Moreover, these ion channels have a role in several neuropathological events such as neuronal cell death, brain tumor progression and strokes. Although Rho GTPases-dependent pathways have been extensively studied, how they converge with TRP channels in the development or progression of neuropathologies is poorly understood. Herein, we review recent evidence and insights that link TRP channels activity to downstream Rho GTPase signaling or modulation. Moreover, using the TRIP database, we establish associations between possible mediators of Rho GTPase signaling with TRP ion channels. As such, we propose mechanisms that might explain the TRP-dependent modulation of Rho GTPases as possible pathways participating in the emergence or maintenance of neuropathological conditions.

General Aspects of Metal Ions as Signaling Agents in Health and Disease

This review focuses on the current knowledge on the involvement of metal ions in signaling processes within the cell, in both physiological and pathological conditions. The first section is devoted to the recent discoveries on magnesium and calcium-dependent signal transduction-the most recognized signaling agents among metals. The following sections then describe signaling pathways where zinc, copper, and iron play a key role. There are many systems in which changes in intra- and extra-cellular zinc and copper concentrations have been linked to important downstream events, especially in nervous signal transduction. Iron signaling is mostly related with its homeostasis. However, it is also involved in a recently discovered type of programmed cell death, ferroptosis. The important differences in metal ion signaling, and its disease-leading alterations, are also discussed.

Low Serum Magnesium Levels Are Associated With Hemorrhagic Transformation After Thrombolysis in Acute Ischemic Stroke

Background: In patients with acute ischemic stroke, hemorrhagic transformation is a major complication after intravenous thrombolysis. This study aimed to investigate the relationship between serum magnesium levels and hemorrhagic transformation (HT) after thrombolytic therapy.

Methods: We retrospectively analyzed data from 242 patients who received thrombolytic therapy at the Second Affiliated Hospital of the Wenzhou Medical University in China. Baseline serum magnesium levels were measured before intravenous thrombolysis, and the occurrence of HT was evaluated using computed tomography images reviewed within 24–36 h after therapy. The relationship between serum magnesium levels and HT was examined using multivariate logistic regression, subgroup analysis, and restricted cubic spline models.

Results: Of the 242 included patients, 43 (17.8%) developed HT. Patients with HT had significant lower serum magnesium levels than those without HT (0.81 ± 0.08 vs. 0.85 ± 0.08 mmol/L, p = 0.007). Multivariable logistic regression analysis indicated that patients with higher serum magnesium levels had lower risk of HT (OR per 0.1-mmol/L increase 0.43, 95% CI 0.27–0.73, p = 0.002). However, this association did not persist when baseline levels of serum magnesium were higher than the median value (0.85 mmol/L) in subgroup analysis (OR per 0.1-mmol/L increase 0.58, 95% CI 0.14–2.51, p = 0.47). This threshold effect was also observed in the restricted cubic spline model when serum magnesium levels were above 0.88 mmol/L. No association between symptomatic HT and serum magnesium levels was observed in our study (OR per 0.1-mmol/L increase 0.52, 95% CI 0.25–1.11, p = 0.092).

Conclusions: Lower serum magnesium levels in patients with ischemic stroke are associated with an increased risk of HT after intravenous thrombolysis, but perhaps only when serum magnesium is below a certain minimal concentration.

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.

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.

Nano-micrometer surface roughness gradients reveal topographical influences on differentiating responses of vascular cells on biodegradable magnesium

Distinctively directing endothelial cells (ECs) and smooth muscle cells (SMCs), potentially by surface topography cue, is of central importance for enhancing bioefficacy of vascular implants. For the first time, surface gradients with a broad range of nano-micrometer roughness are developed on Mg, a promising next-generation biodegradable metal, to carry out a systematic study on the response of ECs and SMCs. Cell adhesion, spreading, and proliferation are quantified along gradients by high-throughput imaging, illustrating drastic divergence between ECs and SMCs, especially in highly rough regions. The profound role of surface topography overcoming the biochemical cue of released Mg²⁺ is unraveled at different roughness ranges for ECs and SMCs. Further insights into the underlying regulatory mechanism are gained at subcellular and gene levels. Our work enables high-efficient exploration of optimized surface morphology for modulating favored cell selectivity of promoting ECs and suppressing SMCs, providing a potential strategy to achieve rapid endothelialization for Mg.

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Surface topography stimuli was engineered on Mg with varying roughness gradients.

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Ridge/valley network feature on Mg overperforms the influence of Mg²⁺.

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Optimized roughness facilitates proliferation of ECs while suppressing SMCs.

TRPM6 and TRPM7: Novel players in cell intercalation during vertebrate embryonic development

A common theme in organogenesis is how the final structure of organs emerge from epithelial tube structures, with the formation of the neural tube being one of the best examples. Two types of cell movements co-occur during neural tube closure involving the migration of cells toward the midline of the embryo (mediolateral intercalation or convergent extension) as well as the deep movement of cells from inside the embryo to the outside of the lateral side of the neural plate (radial intercalation). Failure of either type of cell movement will prevent neural tube closure, which can produce a range of neural tube defects (NTDs), a common congenital disease in humans. Numerous studies have identified signaling pathways that regulate mediolateral intercalation during neural tube closure. Less understood are the pathways that govern radial intercalation. Using the Xenopus laevis system, our group reported the identification of transient receptor potential (TRP) channels, TRPM6 and TRPM7, and the Mg²⁺ ion they conduct, as novel and key factors regulating both mediolateral and radial intercalation during neural tube closure. Here we broadly discuss tubulogenesis and cell intercalation from the perspective of neural tube closure and the respective roles of TRPM7 and TRPM6 in this critical embryonic process.

Salt Preform Texturing of Absorbable Zn Substrates for Bone-implant Applications

Surface roughness is an important factor in improving the bone-implant contact area to enhance bone regeneration, yet this aspect has not been applied to absorbable metals. Textured zinc surfaces with varying degrees of surface roughness were produced using a salt-preform method with fine- and coarse-grained salts and compared to a polished control sample. The resulting surfaces were characterized by scanning electron microscopy (SEM), surface roughness, corrosion rates, and in vitro cytotoxicity. The resulting textured surfaces exhibit micron-sized cavities and increased roughness consistent with the initial salt particle size. The corrosion rate was shown to accelerate significantly as compared to the polished control sample, and pre-osteoblasts displayed healthy morphologies on the textures. The results confirm textured zinc surfaces support cell adhesion and can be used to control the corrosion rate. This study represents an important intermediate step that can be applied to porous absorbable metal scaffolds for bone-implant applications.

Influences of calcium and magnesium ions on cellular antioxidant activity (CAA) determination

The cellular antioxidant activity (CAA) assay is wildly used for quantifying antioxidant activities of foods and dietary supplements in vitro. Among various incubation and handling buffers used in different laboratories, the inconsistence in concentrations of ions, particularly calcium and magnesium, has somehow been neglected. We hired the Hank's balanced salt solution with or without calcium and magnesium to perform CAA assay in Caco-2 cells and HepG2 cells, evaluating the impacts of these cations. The absence of calcium and magnesium reduced intracellular ROS level and underestimated the CAA of quercetin, Trolox and catechin. The abnormally high extracellular calcium and magnesium can also produce inaccurate results. Hank's buffer is recommended to ensure the accuracy and reproducibility. It elucidates precautions must be taken on these cations' concentrations of the buffers while conducting CAA determinations on different types of cells and when comparing foods and beverages with various calcium/magnesium contents.