Magnesium sulfate prevents maternal inflammation-induced impairment of learning ability and memory in rat offspring

Circ_19038 and lnc-AK016022 synergistically regulate Sirt1 to promote remyelination and alleviate white matter injury in preterm mice

Maternal inflammation can lead to premature birth and fetal brain damage. CircRNA_19038 and lncRNA-AK016022 have been shown to be significantly reduced in brain tissues of preterm mice, while whether they are involved in the regulation of preterm white matter injury remains to be explored. Pregnant mice were intraperitoneally injected with lipopolysaccharide (LPS) to establish a preterm brain injury model. Healthy mice born at term served as controls. Lentivirus-mediated circ_19038 overexpression vector (LV-circ_19038), LV-lnc-AK016022, LV-Sirt1 and LV-sh-Sirt1 were administered to preterm mice through the ventricles. The expression levels of circ_19038, lnc-AK016022 and Sirt1 in the brain tissues of preterm mice were significantly lower than those of full-term healthy mice, and circ_19038 and lnc-AK016022 were co-localized in the brain tissues. Upregulation of circ_19038 or/and lnc-AK016022 promoted remyelination and alleviated white matter structural damage, neuroinflammation, and long-term cognitive and motor deficits in preterm mice, and the combined effect of circ_19038 and lnc-AK016022 showed better results. Primary mouse neuronal cells were isolated to investigate the regulatory effects of circ_19038 and lnc-AK016022 on Sirt1. Circ_19038 and lnc-AK016022 jointly promoted the expression of Sirt1 by adsorbing miR-1b and miR-328, respectively. Moreover, silencing Sirt1 antagonized the beneficial effects of circ_19038 or/and lnc-AK016022 on brain white matter injury in preterm mice. In conclusion, circ_19038 and lnc-AK016022 synergistically regulated Sirt1 expression to promote remyelination and alleviate white matter injury in preterm mice.

Effects of mid‑gestational sevoflurane and magnesium sulfate on maternal oxidative stress, inflammation and fetal brain histopathology

Models of inflammation, oxidative stress, hyperoxia and hypoxia have demonstrated that magnesium sulfate (MgSO4), a commonly used drug in obstetrics, has neuroprotective potential. In the present study, the effects of MgSO4 treatment on inflammation, oxidative stress and fetal brain histopathology were evaluated in an experimental rat model following sevoflurane (Sv) exposure during the mid-gestational period. Rats were randomly divided into groups: C (control; no injections or anesthesia), Sv (exposure to 2.5% Sv for 2 h), MgSO4 (administered 270 mg/kg MgSO4 intraperitoneally) and Sv + MgSO4 (Sv administered 30 min after MgSO4 injection). Inflammatory and oxidative stress markers were measured in the serum and neurotoxicity was investigated histopathologically in fetal brain tissue. Short-term mid-gestational exposure to a 1.1 minimum alveolar concentration of Sv did not significantly increase the levels of any of the measured biochemical markers, except for TNF-α. Histopathological evaluations demonstrated no findings suggestive of pathological apoptosis, neuroinflammation or oxidative stress-induced cell damage. MgSO4 injection prior to anesthesia caused no significant differences in biochemical or histopathological marker levels compared to the C and Sv groups. The present study indicated that short-term exposure to Sv could potentially be considered a harmless external stimulus to the fetal brain.

Magnesium sulfate and risk of hypoxic-ischemic encephalopathy in a high-risk cohort

BACKGROUND

Hypoxic-ischemic encephalopathy contributes to morbidity and mortality among neonates ≥36 weeks of gestation. Evidence of preventative antenatal treatment is limited. Magnesium sulfate has neuroprotective properties among preterm fetuses. Hypertensive disorders of pregnancy are a risk factor for hypoxic-ischemic encephalopathy, and magnesium sulfate is recommended for maternal seizure prophylaxis among patients with preeclampsia with severe features.

OBJECTIVE

(1) Determine trends in the incidence of hypertensive disorders of pregnancy, antenatal magnesium sulfate, and hypoxic-ischemic encephalopathy; (2) evaluate the association between hypertensive disorders of pregnancy and hypoxic-ischemic encephalopathy; and (3) evaluate if, among patients with hypertensive disorders of pregnancy, the odds of hypoxic-ischemic encephalopathy is mitigated by receipt of antenatal magnesium sulfate.

STUDY DESIGN

We analyzed a prospective cohort of live births ≥36 weeks of gestation between 2012 and 2018 within the California Perinatal Quality Care Collaborative registry, linked with the California Department of Health Care Access and Information files. We used Cochran-Armitage tests to assess trends in hypertensive disorders, encephalopathy diagnoses, and magnesium sulfate utilization and compared demographic factors between patients with or without hypertensive disorders of pregnancy or treatment with magnesium sulfate. Hierarchical logistic regression models were built to explore if hypertensive disorders of pregnancy were associated with any severity and moderate/severe hypoxic-ischemic encephalopathy. Separate hierarchical logistic regression models were built among those with hypertensive disorders of pregnancy to evaluate the association of magnesium sulfate with hypoxic-ischemic encephalopathy.

RESULTS

Among 44,314 unique infants, the diagnosis of hypoxic-ischemic encephalopathy, maternal hypertensive disorders of pregnancy, and the use of magnesium sulfate increased over time. Compared with patients with hypertensive disorders of pregnancy alone, patients with hypertensive disorders treated with magnesium sulfate represented a high-risk population. They were more likely to be publicly insured, born between 36 and 38 weeks of gestation, be small for gestational age, have lower Apgar scores, require a higher level of resuscitation at delivery, have prolonged rupture of membranes, experience preterm labor and fetal distress, and undergo operative delivery (all P<.002). Hypertensive disorders of pregnancy were associated with hypoxic-ischemic encephalopathy (adjusted odds ratio, 1.26 [95% confidence interval, 1.13-1.40]; P<.001) and specifically moderate/severe hypoxic-ischemic encephalopathy (adjusted odds ratio, 1.26 [95% confidence interval, 1.11-1.42]; P<.001). Among patients with hypertensive disorders of pregnancy, treatment with magnesium sulfate was associated with 29% reduction in the odds of neonatal hypoxic-ischemic encephalopathy (adjusted odds ratio, 0.71 [95% confidence interval, 0.52-0.97]; P=.03) and a 37% reduction in the odds of moderate/severe neonatal hypoxic-ischemic encephalopathy (adjusted odds ratio, 0.63 [95% confidence interval, 0.42-0.94]; P=.03).

CONCLUSION

Hypertensive disorders of pregnancy are associated with hypoxic-ischemic encephalopathy and, specifically, moderate/severe disease. Among people with hypertensive disorders, receipt of antenatal magnesium sulfate is associated with a significant reduction in the odds of hypoxic-ischemic encephalopathy and moderate/severe disease in a neonatal cohort admitted to neonatal intensive care unit at ≥36 weeks of gestation. The findings of this observational study cannot prove causality and are intended to generate hypotheses for future clinical trials on magnesium sulfate in term infants.

Neuroprotective Effects of Artificial Cerebrospinal Fluid: Analysis of Brainstem Auditory-Evoked Potential Monitoring During Microvascular Decompression in 117 Consecutive Patients

BACKGROUND AND OBJECTIVES

To study the efficacy of irrigation with artificial cerebrospinal fluid (aCSF) for protection of cranial nerves during surgery; the time required for recovery of brainstem auditory-evoked potentials (BAEPs) that would reflect cochlear function was analyzed in comparison with that for saline irrigation.

METHODS

This retrospective study included 117 consecutive patients (95 women, mean age 51.5 ± 11.4 year) who underwent microvascular decompression for hemifacial spasm. During surgery, BAEPs were monitored to avoid damage to the auditory pathways. When a delayed latency of >1 ms or a decrease in amplitude of >50% was detected in BAEP wave V, surgical maneuvers were halted, and the operative field was irrigated with saline or aCSF. Saline was used for irrigation in 58 patients and aCSF in the other 59. The time required for BAEP recovery at the first halt in each patient was analyzed, and the results were compared between the groups.

RESULTS

Surgical procedures were interrupted because of BAEP latency delays or decreases in amplitude in 51 of the patients in the saline group and 54 in the aCSF group. In both groups, the latencies and amplitudes recovered significantly with time and both recovered earlier after aCSF irrigation than after saline irrigation. Hearing outcome was not significantly different between 2 groups.

CONCLUSION

aCSF is effective for protection of cochlear nerve and promotes recovery from transient dysfunction during surgery. The protective effect may be attributed to multiple factors including conditioned pH, electrolyte composition, glucose, and microelements, such as magnesium and phosphate.

MDM2 upregulation induces mitophagy deficiency via Mic60 ubiquitination in fetal microglial inflammation and consequently neuronal DNA damage caused by exposure to ZnO-NPs during pregnancy

During pregnancy, the human body is quite vulnerable to external stimuli. Zinc oxide nanoparticles (ZnO-NPs) are widely used in daily life, and they enter the human body via environmental or biomedical exposure, thus having potential risks. Although accumulating studies have demonstrated the toxic effects of ZnO-NPs, few studies have addressed the effect of prenatal ZnO-NP exposure on fetal brain tissue development. Here, we systematically studied ZnO-NP-induced fetal brain damage and the underlying mechanism. Using in vivo and in vitro assays, we found that ZnO-NPs could cross the underdeveloped bloodbrain barrier and enter fetal brain tissue, where they could be endocytosed by microglia. ZnO-NP exposure impaired mitochondrial function and induced autophagosome overaccumulation by downregulation of Mic60, thus inducing microglial inflammation. Mechanistically, ZnO-NPs increased Mic60 ubiquitination by activating MDM2, resulting in imbalanced mitochondrial homeostasis. Inhibition of Mic60 ubiquitination by MDM2 silencing significantly attenuated the mitochondrial damage induced by ZnO-NPs, thereby preventing autophagosome overaccumulation and reducing ZnO-NP-mediated inflammation and neuronal DNA damage. Our results demonstrate that ZnO-NPs are likely to disrupt mitochondrial homeostasis, inducing abnormal autophagic flux and microglial inflammation and secondary neuronal damage in the fetus. We hope the information provided in our study will improve the understanding of the effects of prenatal ZnO-NP exposure on fetal brain tissue development and draw more attention to the daily use of and therapeutic exposure to ZnO-NPs among pregnant women.

Effect of magnesium sulfate treatment on mediators of endothelial dysfunction and electrolytes in mild and severe preeclampsia: A case-control study

Background and Aims

Magnesium sulfate (MgSO4) treatment is widely used for the prevention of eclamptic seizures. However, its effect on mediators of endothelial dysfunction (ED) and electrolytes remains unclear. We evaluated the effects of MgSO4 treatment on mediators of ED and electrolytes.

Methods

We recruited 100 women comprising 50 severe, 50 mild preeclampsia (PE) as cases and 50 normotensive pregnant women as controls from the Sampa Government Hospital, Ghana. We estimated for adrenomedullin (AM), calcitonin gene-related peptide (CGRP), soluble forms of intercellular adhesion molecule-1 (sICAM-1), Na+, K+, and Mg2+ before MgSO4 treatment, 24 h after MgSO4 treatment, and 48 h after delivery. p < 0.05 were considered significant for statistical analyses.

Results

Levels of AM, sICAM-1, and Na+ decreased significantly at 24 h after MgSO4 treatment and 48 h after delivery among PE women compared to the AM levels before treatment (p < 0.0001). The levels of CGRP and Mg2+ increased significantly after 24 h of MgSO4 treatment and 48 h after delivery among PE compared to the AM levels before treatment (p < 0.0001). The changes in AM, sICAM-1, CGRP, and Mg2+ at 24 h after treatment and 48 h after delivery were significantly higher in severe compared to mild PE (p < 0.0001). AM levels reduced significantly by 14.7% in mild and 42.7% in severe PE after MgSO₄ treatment (p < 0.05). sICAM-1 levels reduced significantly by 20.9% in mild and 25% in severe PE after MgSO₄ treatment. After MgSO₄ treatment, there was significant increase of 42.1% and >100% in CGRP levels in mild and severe PE, respectively (p < 0.05). After MgSO₄ treatment, Mg²⁺ levels increased significantly by 67.0% and 63.8% in mild and severe PE, respectively (p < 0.05).

Conclusion

MgSO₄ treatment reduces AM, sICAM-1, and sodium levels but improves magnesium and CGRP in severe than mild PE thus have more beneficial role in severe PE.

Long-term effects of prophylactic MgSO4 in maternal immune activation rodent model at adolescence and adulthood

The effects of MgSO₄ as an anti-inflammatory agent in pregnant women have been investigated in the last few years. Infections can cause an inflammatory reaction involving the placenta membranes and amniotic cavity. They may have short-term effects on the mother and her fetuses, like preterm birth, cerebral palsy, and developmental delay. Despite the alleged advantages of MgSO₄ as a neuroprotective agent in the preterm brain, the long-term molecular and behavioral function of MgSO₄ has not been fully elucidated. Here, we investigated the long-term effect of antenatal MgSO₄ , during late gestation, on offspring's behavior focusing on cognitive function, motor activity, and social cognition in adolescence and adulthood, and explored its influence on brain gene expression (e.g., ErbB signaling, pro-inflammatory, and dopaminergic markers) in adulthood. A significant abnormal exploratory behavior of offspring of MgSO₄ -treated dams was found compared to the control group in both adolescence and adulthood. Furthermore, we found that adult females exposed to MgSO₄ under inflammation displayed working and recognition memory impairment. A reduction in IL-6 expression was detected in the prefrontal cortex, and hippocampus specimens derived from LPS-Mg-treated group. In contrast, an imbalanced expression of dopamine 1 and 2 receptors was detected only in prefrontal cortex specimens. Besides, we found that MgSO₄ ameliorated the overexpression of the Nrg1 and Erbb4 receptors induced by LPS in the hippocampus. Thus, MgSO₄ treatment for preventing brain injuries can adversely affect offspring cognition behavior later in life, depending on the sex and age of the offspring.

Effect of Neuroprotective Magnesium Sulfate Treatment on Brain Transcription Response to Hypoxia Ischemia in Neonate Mice

MgSO₄ is widely used in the prevention of preterm neurological disabilities but its modes of action remain poorly established. We used a co-hybridization approach using the transcriptome in 5-day old mice treated with a single dose of MgSO₄ (600 mg/kg), and/or exposed to hypoxia-ischemia (HI). The transcription of hundreds of genes was altered in all the groups. MgSO₄ mainly produced repressions culminating 6 h after injection. Bio-statistical analysis revealed the repression of synaptogenesis and axonal development. The putative targets of MgSO₄ were Mnk1 and Frm1. A behavioral study of adults did not detect lasting effects of neonatal MgSO₄ and precluded NMDA-receptor-mediated side effects. The effects of MgSO₄ plus HI exceeded the sum of the effects of separate treatments. MgSO₄ prior to HI reduced inflammation and the innate immune response probably as a result of cytokine inhibition (Ccl2, Ifng, interleukins). Conversely, MgSO₄ had little effect on HI-induced transcription by RNA-polymerase II. De novo MgSO₄-HI affected mitochondrial function through the repression of genes of oxidative phosphorylation and many NAD-dehydrogenases. It also likely reduced protein translation by the repression of many ribosomal proteins, essentially located in synapses. All these effects appeared under the putative regulatory MgSO₄ induction of the mTORC2 Rictor coding gene. Lasting effects through Sirt1 and Frm1 could account for this epigenetic footprint.

Maternal Progesterone Treatment Reduces Maternal Inflammation-Induced Fetal Brain Injury in a Mouse Model of Preterm Birth

Maternal natural vaginal progesterone (nVP) administration has been shown to reduce the risk of preterm birth (PTB). The largest randomized trial of nVP for PTB (OPPTIMUM) noted a sonographic reduction in neonatal brain injury following nVP treatment. We investigated the neuroinflammatory protective effect of maternal nVP in a mouse model for maternal inflammation. Pregnant mice (n = 24) were randomized to nVP (1 mg/day) or vehicle from days 13-16 of gestation. At days 15 and 16, lipopolysaccharide (30 μg) or saline were administered. Mice were sacrificed 4 h following the last injection. Fetal brains and placentas were collected. Levels of NF-κB, nNOS, IL-6, and TNFα were determined by Western blot. Maternal lipopolysaccharide significantly increased fetal brain levels of IL-6 (0.33 ± 0.02 vs. 0.11 ± 0.01 u), TNFα (0.3 ± 0.02 vs. 0.10 ± 0.01 u), NF-κB (0.32 ± 0.01 vs. 0.17 ± 0.01 u), and nNOS (0.24 ± 0.04 vs. 0.08 ± 0.01 u), and reduced the total glutathione levels (0.014 ± 0.001 vs. 0.026 ± 0.001 pmol/μl; p < 0.01) compared with control. Maternal nVP significantly reduced fetal brain levels of IL-6 (0.14 ± 0.01 vs. 0.33 ± 0.02 u), TNFα (0.2 ± 0.06 vs. 0.3 ± 0.02 u), NF-κB (0.16 ± 0.01 vs 0.32 ± 0.01 u), and nNOS (0.14 ± 0.01 vs 0.24 ± 0.04 u), and prevented the reduction of fetal brain total glutathione levels (0.022 ± 0.001 vs. 0.014 ± 0.001 pmol/μl; p < 0.01) to levels similar to controls. A similar pattern was demonstrated in the placenta. Maternal nVP for PTB may protect the fetal brain from inflammation-induced brain injury by inhibiting specific inflammatory and oxidative pathways in both brain and placenta.

Short-Term Effect of MgSO4 on the Expression of NRG-ErbB, Dopamine, GABA, and Glutamate Systems in the Fetal Rat Brain

MgSO₄ has been used for the past two decades as neuroprotective treatment in a variety of preterm conditions. Despite the putative advantages of MgSO₄ as a neuroprotective agent in the preterm brain, the short- and long-term molecular function of MgSO₄ as a neuroprotective agent has not been fully elucidated. Neuregulin (NRG1)-ErbB4 signaling plays a critical role in embryonic brain development, in the biology of dopaminergic, GABAergic, and glutamatergic systems. We hypothesize that this pathway may be associated with the neuroprotective role of MgSO₄. The current study aims to investigate the ability of MgSO₄ to modulate the normal developing expression pattern of selected genes related to the NRG1-ErbB, dopaminergic, GABAergic, and glutamatergic systems. We demonstrate that overall short-term treatment of dam rats with MgSO₄ affects the expression of fetal brain NRG1, NRG3, ErbB4, GAD67, tyrosine hydroxylase (TH), dopamine D₂ and D₁ receptors, GluN1, and GluN2B. More specifically, the administration of MgSO₄ alters the expression of NRG-ErbB, GAD67, TH, and D2R at early gestation day 16 (GD16) regardless of the activation of the maternal immune system by lipopolysaccharide (LPS). Our data suggest that MgSO₄ treatment may affect the expression of major neuronal systems and pathways mostly at an early gestation day. These changes might be an initial clue (foundation stone) in the molecular mechanism that underlies the beneficial effect of MgSO₄ as a neuroprotective agent for the developmental brain.

Magnesium Increases the Protective Effect of Citicoline on Aluminum Chloride-induced Cognitive Impairment

Objective

Alzheimer's disease is a popular neurodegenerative disorder which is growing in the elderly people. Exposure to environmental pollutant like aluminum could trigger or accelerate its involved mechanisms like tau phosphorylation. The current study will evaluate the effect of alone or co-administration of Citicoline or/and magnesium on the aluminum chloride induced memory impairment.

Methods

Male albino mice were randomly divided into different groups (n = 7). Memory impairment was induced via orally administration of 300 mg/kg Aluminum Chloride for 28 days. Based on respective group, animals received 100, 250, 500 mg/kg of Citicoline or 50, 100, 150 mg/kg of Magnesium sulfate (MgSO4), intraperitoneally. In co-administration, 50 mg/kg of MgSO4 injected concomitantly with 100, 250, or 500 mg/kg of Citicoline. Rivastigmine (2 mg/kg intraperitoneally) was used as a positive control. Memory was evaluated using the Object Recognition Task (ORT) and Passive Avoidance Test (PAT).

Results

The studied doses of Citicoline or MgSO4 when administered individually showed significant increase in the discrimination index in ORT and latency time in the PAT compared to the Aluminium chloride (AlCl3) treated group. Concomitant injection of 50 mg/kg MgSO4 with the different doses of Citicoline strongly increased the above indices values in comparison to each alone.

Conclusion

The findings show, individual administration of Citicoline or MgSO4 inverted the AlCl3-induced memory impairment in a dose independent manner. The addition of MgSO4 to the Citicoline showed a synergistic effect in the PAT and likely additive effect in the ORT.

A Systematic Review of Magnesium Sulfate for Perinatal Neuroprotection: What Have We Learnt From the Past Decade?

There is an important unmet need to improve long term outcomes of encephalopathy for preterm and term infants. Meta-analyses of large controlled trials suggest that maternal treatment with magnesium sulfate (MgSO₄) is associated with a reduced risk of cerebral palsy and gross motor dysfunction after premature birth. However, to date, follow up to school age has found an apparent lack of long-term clinical benefit. Because of this inconsistency, it remains controversial whether MgSO₄ offers sustained neuroprotection. We systematically reviewed preclinical and clinical studies reported from January 1 2010, to January 31 2020 to evaluate the most recent advances and knowledge gaps relating to the efficacy of MgSO₄ for the treatment of perinatal brain injury. The outcomes of MgSO₄ in preterm and term-equivalent animal models of perinatal encephalopathy were highly inconsistent between studies. None of the perinatal rodent studies that suggested benefit directly controlled body or brain temperature. The majority of the studies did not control for sex, study long term histological and functional outcomes or use pragmatic treatment regimens and many did not report controlling for potential study bias. Finally, most of the recent preterm or term human studies that tested the potential of MgSO₄ for perinatal neuroprotection were relatively underpowered, but nevertheless, suggest that any improvements in neurodevelopment were at best modest or absent. On balance, these data suggest that further rigorous testing in translational preclinical models of perinatal encephalopathy is essential to ensure safety and best regimens for optimal preterm neuroprotection, and before further clinical trials of MgSO₄ for perinatal encephalopathy at term are undertaken.

Short-term effects of early initiation of magnesium infusion combined with cooling after hypoxia-ischemia in term piglets

BACKGROUND

Neuroprotection from therapeutic hypothermia (HT) is incomplete, therefore additional strategies are necessary to improve long-term outcomes. We assessed the neuroprotective efficacy of magnesium sulfate (MgSO₄) bolus and infusion over 48 h plus HT in a piglet model of term neonatal encephalopathy (NE).

METHODS

Fifteen newborn piglets were randomized following hypoxia-ischemia (HI) to: (i) MgSO₄ 180 mg/kg bolus and 8 mg/kg/h infusion with HT (Mg+HT) or (ii) HT and saline 0.5 ml/h (HT). Treatments were initiated 1 h post-HI; HT administered for 12 h (33.5 °C). HI was performed by transient carotid occlusion and inhalation of 6% O₂ for 20-25 min. Primary outcomes included aEEG, magnetic resonance spectroscopy (MRS) at 24, and 48 h, and immunohistochemistry.

RESULTS

MgSO₄ bolus and infusion was well tolerated (no hypotension) and doubled serum magnesium (0.72 vs 1.52 mmol/L) with modest (16%) rise in CSF. In Mg+HT compared to HT, there was overall reduced cell death (p = 0.01) and increased oligodendrocytes (p = 0.002). No improvement was seen on aEEG recovery (p = 0.084) or MRS (Lac/NAA; PCr/Pi; NTP/epp) (p > 0.05) at 48 h.

CONCLUSION

Doubling serum magnesium with HT was safe; however, the small incremental benefit of Mg+HT compared to HT is unlikely to translate into substantive long-term improvement. Such an incremental effect might justify further study of MgSO₄ in combination with multiple therapies.

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.

IL-1 receptor antagonist therapy mitigates placental dysfunction and perinatal injury following Zika virus infection

Zika virus (ZIKV) infection during pregnancy causes significant adverse sequelae in the developing fetus, and results in long-term structural and neurologic defects. Most preventive and therapeutic efforts have focused on the development of vaccines, antivirals, and antibodies. The placental immunologic response to ZIKV, however, has been largely overlooked as a target for therapeutic intervention. The placental inflammatory response, specifically IL-1β secretion and signaling, is induced by ZIKV infection and represents an environmental factor that is known to increase the risk of perinatal developmental abnormalities. We show in a mouse model that maternally administrated IL-1 receptor antagonist (IRA; Kineret, or anakinra), following ZIKV exposure, can preserve placental function (by improving trophoblast invasion and placental vasculature), increase fetal viability, and reduce neurobehavioral deficits in the offspring. We further demonstrate that while ZIKV RNA is highly detectable in placentas, it is not correlated with fetal viability. Beyond its effects in the placenta, we show that IL-1 blockade may also directly decrease fetal neuroinflammation by mitigating fetal microglial activation in a dose-dependent manner. Our studies distinguish the role of placental inflammation during ZIKV-infected pregnancies, and demonstrate that maternal IRA may attenuate fetal neuroinflammation and improve perinatal outcomes.

[Study on the protective mechanism of autophagy on cartilage by magnesium sulfate]

Objective

To investigate the mechanism of magnesium sulfate in protecting rabbit cartilage by initiating autophagy.

Methods

Twenty-four adult female New Zealand rabbits were used to prepare post-traumatic osteoarthritis (PTOA) models by anterior cruciate ligament transection. Then, the PTOA models were randomly divided into PTOA group, distilled water group, and magnesium sulfate group, with 8 rabbits in each group. Immediately after operation, the distilled water group and the magnesium sulfate group were injected with 0.5 mL distilled water and 20 mmol/L magnesium sulfate solution in the joint cavity 3 times a week for 4 weeks, respectively. The PTOA group was not treated. The general condition of the animals was observed after operation. After 4 weeks, the expressions of tumor necrosis factor α (TNF-α) and collagen typeⅡ in the joint fluid and the expression of collagen type Ⅱ in venous blood were detected by ELISA assay. The protein expressions of transient receptor potential channel vanilloid 5 (TRPV5) and microtubule associated protein 1 light chain 3 (LC3; LC3-Ⅱ/LC3-Ⅰ) in femoral cartilage were detected by Western blot. The mRNA expressions of interleukin 1β (IL-1β), TNF-α, matrix metalloproteinases 3 (MMP-3) in synovial tissue and collagen type Ⅱ, Aggrecan (AGN), SOX9 in cartilage tissue were detected by real-time fluorescence quantitative PCR. Cartilage tissue sections were stained with HE staining, Masson staining, and Alcian blue staining and scored according to the modified histological osteoarthritis (OA) score.

Results

All animals survived until the experiment was completed. Compared with the other two groups, the expression of TNF-α in joint effusion and collagen type Ⅱ in joint effusion and venous blood were decreased in magnesium sulfate group; the protein expression of TRPV5 decreased, and the ratio of LC3-Ⅱ/LC3-Ⅰ increased significantly; the mRNA expressions of IL-1β, TNF-α, and MMP-3 in synovial tissue were decreased, and the mRNA expressions of collagen type Ⅱ, AGN, and SOX9 in cartilage tissue were increased; OA scores also decreased significantly. All differences were statistically significant ( P<0.05). There was no significant difference in the above indicators between the PTOA group and the distilled water group ( P>0.05).

Conclusion

Intra-articular injection of magnesium sulfate can reduce intra-articular inflammation, reduce the loss of collagen type Ⅱ and AGN, and is beneficial to cartilage regeneration in rabbits. The mechanism may be related to the initiation of chondroautophagy by inhibiting the calcium channel TRPV5.

Maternal pomegranate juice attenuates maternal inflammation-induced fetal brain injury by inhibition of apoptosis, neuronal nitric oxide synthase, and NF-κB in a rat model

BACKGROUND

Maternal inflammation is a risk factor for neonatal brain injury and future neurological deficits. Pomegranates have been shown to exhibit anti-inflammatory, anti-apoptotic and anti-oxidant activities.

OBJECTIVE

We hypothesized that pomegranate juice (POM) may attenuate fetal brain injury in a rat model of maternal inflammation.

STUDY DESIGN

Pregnant rats (24 total) were randomized for intraperitoneal lipopolysaccharide (100 μg/kg) or saline at time 0 at 18 days of gestation. From day 11 of gestation, 12 dams were provided ad libitum access to drinking water, and 12 dams were provided ad libitum access to drinking water with pomegranate juice (5 mL per day), resulting in 4 groups of 6 dams (saline/saline, pomegranate juice/saline, saline/lipopolysaccharide, pomegranate juice/lipopolysaccharide). All dams were sacrificed 4 hours following the injection and maternal blood and fetal brains were collected from the 4 treatment groups. Maternal interleukin-6 serum levels and fetal brain caspase 3 active form, nuclear factor-κB p65, neuronal nitric oxide synthase (phosphoneuronal nitric oxide synthase), and proinflammatory cytokine levels were determined by enzyme-linked immunosorbent assay and Western blot.

RESULTS

Maternal lipopolysaccharide significantly increased maternal serum interleukin-6 levels (6039 ± 1039 vs 66 ± 46 pg/mL; P < .05) and fetal brain caspase 3 active form, nuclear factor-κB p65, phosphoneuronal nitric oxide synthase, and the proinflammatory cytokines compared to the control group (caspase 3 active form 0.26 ± 0.01 vs 0.20 ± 0.01 U; nuclear factor-κB p65 0.24 ± 0.01 vs 0.1 ± 0.01 U; phosphoneuronal nitric oxide synthase 0.23 ± 0.01 vs 0.11 ± 0.01 U; interleukin-6 0.25 ± 0.01 vs 0.09 ± 0.01 U; tumor necrosis factor-α 0.26 ± 0.01 vs 0.12 ± 0.01 U; chemokine (C-C motif) ligand 2 0.23 ± 0.01 vs 0.1 ± 0.01 U). Maternal supplementation of pomegranate juice to lipopolysaccharide-exposed dams (pomegranate juice/lipopolysaccharide) significantly reduced maternal serum interleukin-6 levels (3059 ± 1121 pg/mL, fetal brain: caspase 3 active form (0.2 ± 0.01 U), nuclear factor-κB p65 (0.22 ± 0.01 U), phosphoneuronal nitric oxide synthase (0.19 ± 0.01 U) as well as the brain proinflammatory cytokines (interleukin-6, tumor necrosis factor-α and chemokine [C-C motif] ligand 2) compared to lipopolysaccharide group.

CONCLUSION

Maternal pomegranate juice supplementation may attenuate maternal inflammation-induced fetal brain injury. Pomegranate juice neuroprotective effects might be secondary to the suppression of both the maternal inflammatory response and inhibition of fetal brain apoptosis, neuronal nitric oxide synthase, and nuclear factor-κB activation.

Magnesium Ions Inhibit the Expression of Tumor Necrosis Factor α and the Activity of γ-Secretase in a β-Amyloid Protein-Dependent Mechanism in APP/PS1 Transgenic Mice

Alzheimer’s disease (AD) is a neurodegenerative disease characterized by cognitive impairment. The neuropathological features of AD are the aggregation of extracellular amyloid β-protein (Aβ) and tau phosphorylation. Recently, AD was found to be associated with magnesium ion (Mg²⁺) deficit and tumor necrosis factor-alpha (TNF-α) elevation in the serum or brains of AD patients. To study the relationship between Mg²⁺ and TNF-α, we used human- or mouse-derived glial and neuronal cell lines or APP/PS1 transgenic (Tg) mice as in vitro and in vivo experimental models, respectively. Our data demonstrates that magnesium-L-threonate (MgT) can decrease the expression of TNF-α by restoring the levels of Mg²⁺ in glial cells. In addition, PI3-K/AKT and NF-κB signals play critical roles in mediating the effects of Mg²⁺ on suppressing the expression of TNF-α. In neurons, Mg²⁺ elevation showed similar suppressive effects on the expression of presenilin enhancer 2 (PEN2) and nicastrin (NCT) through a PI3-K/AKT and NF-κB-dependent mechanism. As the major components of γ-secretase, overexpression of presenilin 1 (PS1), PEN2 and NCT potentially promote the synthesis of Aβ, which in turn activates TNF-α in glial cells. Reciprocally, TNF-α stimulates the expression of PEN2 and NCT in neurons. The crosstalk between TNF-α and Aβ in glial cells and neurons could ultimately aggravate the development and progression of AD.

Fetal Neuroprotection by Magnesium Sulfate: From Translational Research to Clinical Application

Despite improvements in perinatal care, preterm birth still occurs regularly and the associated brain injury and adverse neurological outcomes remain a persistent challenge. Antenatal magnesium sulfate administration is an intervention with demonstrated neuroprotective effects for preterm births before 32 weeks of gestation (WG). Owing to its biological properties, including its action as an N-methyl-d-aspartate receptor blocker and its anti-inflammatory effects, magnesium is a good candidate for neuroprotection. In hypoxia models, including hypoxia-ischemia, inflammation, and excitotoxicity in various species (mice, rats, pigs), magnesium sulfate preconditioning decreased the induced lesions’ sizes and inflammatory cytokine levels, prevented cell death, and improved long-term behavior. In humans, some observational studies have demonstrated reduced risks of cerebral palsy after antenatal magnesium sulfate therapy. Meta-analyses of five randomized controlled trials using magnesium sulfate as a neuroprotectant showed amelioration of cerebral palsy at 2 years. A meta-analysis of individual participant data from these trials showed an equally strong decrease in cerebral palsy and the combined risk of fetal/infant death and cerebral palsy at 2 years. The benefit remained similar regardless of gestational age, cause of prematurity, and total dose received. These data support the use of a minimal dose (e.g., 4 g loading dose ± 1 g/h maintenance dose over 12 h) to avoid potential deleterious effects. Antenatal magnesium sulfate is now recommended by the World Health Organization and many pediatric and obstetrical societies, and it is requisite to maximize its administration among women at risk of preterm delivery before 32 WG.

Magnesium oxide use and reduced risk of dementia: a retrospective, nationwide cohort study in Taiwan

OBJECTIVE

Dietary magnesium may be associated with a lower risk of dementia; however, the impact of magnesium oxide (MgO), a common laxative, on dementia has yet to be elucidated. This study aimed to investigate the association between the usage of MgO and the risk of developing dementia.

METHODS

We used a dataset from the National Health Research Institute Database (NHRID) of Taiwan containing one million randomly sampled subjects to identify patients aged ≥50 years with no history of MgO usage. A total of 1547 patients who had used MgO were enrolled, along with 4641 controls who had not used the MgO propensity score matched by age, gender and comorbidity, at a ratio of 1:3. After adjusting for confounding risk factors, a Cox proportional hazards model was used to compare the risk of developing dementia during a 10 year follow-up period.

RESULTS

Of the enrolled patients, 44 (2.84%) developed dementia, when compared to 199 (4.28%) in the control group. The Cox proportional hazards regression analysis revealed that the patients who had used MgO were less likely to develop dementia with a crude hazard ratio of 0.617 (95% CI, 0.445-0.856, p = .004). After adjusting for age, gender, comorbidity, geographical area and urbanization level of residence, and monthly income, the adjusted hazard ratio was 0.517 (95% CI, 0.412-0.793, p = .001).

CONCLUSIONS

The patients who used MgO had a decreased risk of developing dementia. Further studies on the effects of MgO in reducing the risk of dementia are therefore warranted.

Maternal Inflammation, Fetal Brain Implications and Suggested Neuroprotection: A Summary of 10 Years of Research in Animal Models

A growing body of evidence implies that maternal inflammation during pregnancy is associated with increased risk of neurodevelopmental disorders in the offspring. The pathophysiological mechanisms by which maternal inflammation evokes fetal brain injury and contributes to long-term adverse neurological outcomes are not completely understood. In this review, we summarize 10 years of our research experience on maternal inflammation and the implications upon the fetal/offspring brain. We review our findings regarding the underlying mechanisms that connects maternal inflammation and fetal brain injuries (e.g. cytokines, oxidative stress); we discuss our imaging, pathological and behavioral test results which support brain damage following maternal inflammation; and finally we describe some of the therapeutic strategies which might prevent the damage.

Magnesium sulfate (MG) prevents maternal inflammation induced offspring cerebral injury evident on MRI but not via IL-1β

OBJECTIVE

As maternal treatment with magnesium sulfate (MG) may protect the fetal brain, we sought to assess the inflammation associated neuroprotective potential of MG and its association to interleukin 1β (IL-1β).

METHODS

Pregnant Sprague-Dawley rats at 18-day gestation received i.p. lipopolysaccharide (LPS) or saline. Dams were randomized to treatment with s.c. saline (control), or MG prior to or following the i.p. injection, resulting in three groups. At the end of the treatment, fetal brain IL-1β was quantified for 18 pregnant rats (six of each group). Another 18 pregnant rats delivered spontaneously and pups were allowed to mature. At postnatal day 25, female offspring were examined by magnetic resonance imaging (MRI) and analyzed using voxel based analysis. Apparent diffusion coefficient (ADC) and T2 relaxation protocols were performed to assess white and gray matter injury.

RESULTS

Offspring of LPS-treated dams exhibited (1) significantly increased T2 levels, and (2) increased ADC levels in white and gray matter, consistent with diffuse cerebral injury. Offspring of MG-treated LPS dams demonstrated similar T2 and ADC levels as control dams. Fetal brain IL-1β was significantly increased following maternal LPS compared to control (0.125±0.01 vs 0.100±0.01u, p<0.05). No significant decrease in IL-1β level was observed in response to maternal MG.

CONCLUSIONS

Maternal LPS-induced neonatal brain injury can be prevented by maternal MG. Maternal MG therapy may be effective in human deliveries associated with maternal/fetal inflammation. The absence of a decrease in fetus brain levels of IL-1β following MG treatment implies that the mechanism of MG is not through inhibition of IL-1β production.

SIGNIFICANCE STATEMENT

Intrauterine fetal exposure to maternal inflammation and pro-inflammatory cytokines is associated with adverse offspring neurological outcomes. Although its precise mechanism is not elucidated, magnesium sulfate (MG) is commonly used as neuroprotection for white matter brain injuries in preterm fetuses. A proposed mechanism involves the ability of MG to reduce pro-inflammatory cytokine levels. In the current study, we used a rat model of LPS-induced maternal inflammation to investigate the short-term effect of MG on fetal brain IL-1β levels, and its long-term neuroprotective effect on the offspring brain by using MRI. We demonstrated that maternal administration of MG can prevent long-term neonatal brain injury but, since no decrease was observed in fetal brain IL-1β levels, the neuro-protective mechanism of MG is not mediated by inhibition of IL-1β production.