Natural Killer Cells Disrupt Nerve Fibers by Granzyme H in Atheriosclerotic Cerebral Small Vessel Disease.

Natural killer (NK) cells are enriched in the central nervous system in aging-related atheriosclerotic cerebral small vessel disease (aCSVD), but their roles and underlying mechanism remain to be elucidated. To identify potential cytotoxic molecules released by NK cells in aCSVD lesions, proteomic analysis of cerebrospinal fluid (CSF), plasma, and peripheral NK cells from patients with aCSVD were performed. We found that integrin ß2 (ITGB2), cathepsin D (CTSD), and granzyme H (GZMH) were highly expressed in NK cells. ITGB2 interacted with intercellular adhesion molecule 1 in vascular endothelial cells. As assessed by immunofluorescence and scanning electron microscopy of the blood-brain barrier model, transwell membranes covered with primary human brain microvascular endothelial cells and astrocytes, we demonstrated that the CTSD-mediated degradation of collagen in the blood-brain barrier depended on the cytotoxicity of NK cells in aCSVD. With the immunostaining in vitro and in vivo, GZMH disruption of demyelinated nerve fibers was reversed by cotreatment with the inhibitor 3,4-DCIC during white matter hyperintensity (WMH) in aCSVD. Our results indicate that NK cells contribute to CTSD-induced damage to the blood-brain barrier and GZMH-induced disruption of nerve fibers during WMH in aCSVD.

N-Butylphthalide vs. Human Urinary Kallidinogenase for the Treatment of Acute Ischemic Stroke: Functional Outcome and Impact on Serum VEGF and TNF-α Expressions.

OBJECTIVE: To compare the e!cacy and functional outcomes of dl-3-n-Butylphthalide (NBP) and human urinary kallidinogenase (HUK) on ischemic stroke patients and to determine their effects on serum tumor necrosis factor-alpha (TNF-α) and vascular endothelial growth factor (VEGF). METHODS: A prospective study was conducted on 57 ischemic stroke patients. Functional outcomes were assessed by the National Institute Health Stroke Scale (NIHSS), the modified Rankin Scale (mRS), and the activities of daily living score (ADL), whereas TNF-α and VEGF expressions were measured by enzyme-linked immunosorbent assay (ELISA). RESULTS: TNF-α was significantly down-regulated in the NBP group and upregulated in the control group two weeks after treatment (p=0.017 and p=0.047, respectively). A significant difference in VEGF expressions was observed between the two groups (330.25±120.64 vs. 437.15±137.68, p=0.041) two weeks after treatment. Both groups showed significant improvement in NIHSS and ADL scores three months after treatment (p<0.001), with the NBP group exhibiting improvement in NIHSS scores as early as two weeks after treatment (p=0.008). The three-month NIHSS scores of the two groups were significantly lower than those of the control group (p=0.010 and p=0.008, respectively). Both the NBP and HUK groups showed a significant decline in mRS scores two weeks and three months after treatment (p<0.05). CONCLUSIONS: Both treatments are effective and can significantly promote recovery in stroke patients. Additionally, both options have similar effects in promoting long-term recovery, with NBP exerting a greater impact on serum VEGF and TNF-α expressions.

Protein A immunoadsorption for the treatment of refractory anti-N-methyl-d-aspartate receptor encephalitis: A single-center prospective study.

OBJECTIVE: The aim of this study was to evaluate the efficacy and safety of protein A immunoadsorption (IA) for anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis resistant to intravenous methylprednisolone (IVMP) and intravenous immunoglobulin (IVIG). METHODS: We prospectively evaluated patients with refractory anti-NMDAR encephalitis, treated with protein A IA. Demographic data, clinical characteristics, modified Rankin Score (mRS), and anti-NMDAR antibodies were documented before and after IA and at follow-up. Clinical improvement was defined as a decrease of mRS ≥1. Adverse events were recorded throughout the study. RESULTS: Ten patients with mRS ≥3 were enrolled and treated with protein A IA; treatment was performed for an average of 5.2 times per patient. Among the nine patients with positive serum anti-NMDAR, the titer decreased in seven patients, of which two became negative. The cerebrospinal fluid (CSF) anti-NMDAR titer decreased in all patients, and one became negative. Anti-NMDAR levels were tested in two patients at follow-up and found to have declined continuously. All patients exhibited clinical improvement with a mRS decline ≥1 after IA treatment (median mRS: 5.0 [range, 3.0-5.0] vs. 4.0 [range, 2.0-4.0], p = 0.014), and the median mRS decreased to 1.0 (range, 0-3.0) at follow-up. After IA, all patients exhibited accelerated recovery. No adverse events were observed during IA treatment. CONCLUSION: Protein A IA may be effective for treating IVMP/IVIG-resistant anti-NMDAR encephalitis and well tolerated. It is necessary to initiate larger-scale prospective controlled studies to validate the efficacy and safety of protein A IA in anti-NMDAR encephalitis.

Ketamine Induces Lasting Antidepressant Effects by Modulating the NMDAR/CaMKII-Mediated Synaptic Plasticity of the Hippocampal Dentate Gyrus in Depressive Stroke Model.

Background: Ketamine has been shown to possess lasting antidepressant properties. However, studies of the mechanisms involved in its effects on poststroke depression are nonexistent. Methods: To investigate these mechanisms, Sprague-Dawley rats were treated with a single local dose of ketamine after middle cerebral artery occlusion and chronic unpredicted mild stress. The effects on the hippocampal dentate gyrus were analyzed through assessment of the N-methyl-D-aspartate receptor/calcium/calmodulin-dependent protein kinase II (NMDAR/CaMKII) pathway, synaptic plasticity, and behavioral tests. Results: Ketamine administration rapidly exerted significant and lasting improvements of depressive symptoms. The biochemical analysis showed rapid, selective upregulation and downregulation of the NMDAR2-ß and NMDAR2-α subtypes as well as their downstream signaling proteins ß-CaMKII and α-phosphorylation in the dentate gyrus, respectively. Furthermore, the colocalization analysis indicated a significant and selectively increased conjunction of ß-CaMKII and postsynaptic density protein 95 (PSD95) coupled with a notable decrease in NMDAR2-ß association with PSD95 after ketamine treatment. These changes translated into significant and extended synaptic plasticity in the dentate gyrus. Conclusions: These findings not only suggest that ketamine represents a viable candidate for the treatment of poststroke depression but also that ketamine's lasting antidepressant effects might be achieved through modulation of NMDAR/CaMKII-induced synaptic plasticity in key brain regions.

Case Report: Central Nervous System Immune Reconstitution Inflammatory Syndrome Related to Bacterial Meningitis.

Central nervous system immune reconstitution inflammatory syndrome (CNS-IRIS) describes clinical characteristics that may be observed in previously immunocompromised patients during rapid restoration of immunity function in the presence of a pathogen. There have been no reports about CNS-IRIS related to bacterial meningitis so far. Here, we report a 24-year-old pregnant female patient with bacterial meningitis. Her clinical and neuroradiological condition worsened after induced labor despite great effective anti-infective therapy. CNS-IRIS was considered. Corticosteroids were administered, and the patient gradually recovered. We present the first case of CNS-IRIS associated with bacterial meningitis.

Triglyceride-Glucose Index Linked to Hospital Mortality in Critically Ill Stroke: An Observational Multicentre Study on eICU Database.

Objective: The triglyceride-glucose (TyG) index is a reliable surrogate of insulin resistance and a marker for ischemic stroke (IS) incident. Whether the TyG index predicts stroke outcome remains uncertain. This study investigated the prognostic value of the TyG index in critically ill stroke patients. Methods: This was a retrospective observational study that included stroke patients, and all data were extracted from the eICU Collaborative Research Database. The TyG index was calculated as the ln [fasting glucose level (mg/dL) × triglyceride level (mg/dL)/2]. Outcomes included the hospital and intensive care unit (ICU) death. Multivariate logistic regression was used to determine independent risk factors. The smoothing curves and forest plots were illustrated. Results: A total of 4,570 eligible subjects were enrolled. The mean level of TyG index was 9.1 ± 0.7. The hospital and ICU mortality rate were 10.3 and 5.0%, respectively. TyG index as a continuous variable was associated hospital mortality in univariate analysis (OR 1.723, 95% CI 1.524-1.948, P < 0.001), adjusted model 1 (OR 1.861, 95% CI 1637-2.116, P < 0.001), and adjusted model 2 (OR 2.543, 95% CI 1.588-4.073, P < 0.001). TyG was also associated ICU mortality in univariate analysis (OR 2.146, 95% CI 1.826-2.523, P < 0.001), adjusted model 1 (OR 2.183, 95% CI 1.847-2.580, P < 0.001), and adjusted model 2 (OR 2.672, 95% CI 1.376-5.188, P < 0.001). The smoothing curves observed a continuous linear association after adjusting all covariates both in hospital and ICU mortality. Subgroup analysis demonstrated TyG index was associated with increased risk of hospital and ICU death in critically ill IS (P < 0.05), but not in hemorrhage stroke (P > 0.05). Conclusion: The TyG index is a potential predictor for hospital and ICU mortality in critically ill stroke patients, especially in IS patients.

SIRT1-regulated HMGB1 release is partially involved in TLR4 signal transduction: A possible anti-neuroinflammatory mechanism of resveratrol in neonatal hypoxic-ischemic brain injury.

Neonatal hypoxic-ischemic brain injury (HIBI) is a knotty disease that lacks appropriate treatment. Inflammation is an important contributor to brain damage, and microglia are responsible for eliciting early and pronounced inflammatory reactions in the immature brain after hypoxic-ischemic (HI) insult. Acetylated HMGB1 can be released from immune cells into the extracellular space, where it acts as a danger-associated molecular pattern molecule to activate TLR4 signalling-mediated inflammatory responses. Resveratrol has neuroprotective and anti-inflammatory effects against HIBI, but whether these effects involve the regulation of the TLR4 signalling pathway and whether HMGB1 participates in this process is still unclear. We investigated the anti-inflammatory effects of resveratrol in HIBI and the molecular mechanisms potentially involved in the effect. The in vivo and in vitro results indicated that the level of cytoplasmic HMGB1 in microglia increased after insult and that treating experimental animals or mouse BV2 microglial cells with resveratrol attenuated HI insult-induced neuroinflammation, which was characterized by improved behavioural defects, reduced microglial activation and TLR4/MyD88/NF-κB signalling, and attenuated primary neuronal damage; this was accompanied by the inhibition of HMGB1 nucleoplasmic transfer and extracellular release. EX527 pretreatment reversed these effects. In addition, co-immunoprecipitation confirmed that SIRT1 was directly involved in the HMGB1 acetylation process in BV2 cells after oxygen glucose deprivation. These data demonstrate that resveratrol plays a neuroprotective role in neonatal HIBI by activating SIRT1 to inhibit HMGB1/TLR4/MyD88/NF-κB signalling and subsequent neuroinflammatory responses.

Chronic Unexpected Mild Stress Destroys Synaptic Plasticity of Neurons through a Glutamate Transporter, GLT-1, of Astrocytes in the Ischemic Stroke Rat.

Background and Objective: Chronic unexpected mild stress (CUMS) destroys synaptic plasticity of hippocampal regenerated neurons that may be involved in the occurrence of poststroke depression. Astrocytes uptake glutamate at the synapse and provide metabolic support for neighboring neurons. Currently, we aim to investigate whether CUMS inhibits synaptic formation of regenerated neurons through a glutamate transporter, GLT-1, of astrocytes in the ischemic stroke rats. Method: We exposed the ischemic stroke rats to ceftriaxone, during the CUMS intervention period to determine the effects of GLT-1 on glutamate circulation by immunofluorescence and mass spectrometry and its influences to synaptic plasticity by western blot and transmission electron microscopy. Result: CUMS evidently reduced the level of astroglial GLT-1 in the hippocampus of the ischemic rats (p < 0.05), resulting in smaller amount of glutamate being transported into astrocytes surrounding synapses (p < 0.05), and then expression of synaptophysin was suppressed (p < 0.05) in hippocampal dentate gyrus. The ultrastructures of synapses in dentate gyrus were adversely influenced including decreased proportion of smile synapses, shortened thickness of postsynaptic density, reduced number of vesicles, and widened average distance of the synaptic cleft (all p < 0.05). Moreover, ceftriaxone can promote glutamate circulation and synaptic plasticity (all p < 0.05) by raising astroglial GLT-1 (p < 0.05) and then improve depressive behaviors of the CUMS-induced model rats (p < 0.05). Conclusion: Our study shows that CUMS destroys synaptic plasticity of regenerated neurons in the hippocampus through a glutamate transporter, GLT-1, of astrocytes in the ischemic stroke rats. This may indicate one potential pathogenesis of poststroke depression.

Down-expressed GLT-1 in PSD astrocytes inhibits synaptic formation of NSC-derived neurons in vitro.

Little is known about the effect of astroglial GLT-1 of post-stroke depression (PSD) rat model on the function of neural stem cells (NSCs). This study aimed to investigate whether astroglial GLT-1 of PSD rats affect differentiation of NSCs from neonatal rat hippocampus and synaptic formation of NSC-derived neurons. Astrocytes were isolated from the left hippocampus of normal adult SD rats and PSD rats. A lentiviral vector was used to silence the expression of GLT-1 in astrocytes of PSD rats. NSCs were respectively co-cultured with normal (control), PSD, and GLT-1 silenced astrocytes for 7 days. GLT-1, GFAP, MAP2, Synaptophysin (SYN), glutamate (Glu) and glutamine (Gln) were respectively measured by qRT-PCR, western blot, immunofluorescence and efficient mass spectrometry (MS). PSD astrocytes increased the number of NSC-derived astrocytes, but inhibited the expression of GLT-1 of NSC-derived astrocytes and synapses of NSC-derived neurons. On the basis of the low expression of GLT-1 in PSD astrocytes, we further silenced GLT-1 in PSD astrocytes. Interestingly, GLT-1 silenced PSD astrocytes more obviously inhibited synapses of NSC-derived neurons, but increased the number of NSC-derived neurons and reversed the expression of GLT-1 in NSC-derived astrocytes. At the same time, concentration of glutamate in the medium elevated, and glutamine in the medium gradually reduced. In NSC-derived neurons and astrocytes, glutamate metabolism was also affected by changed GLT-1. Down-expressed GLT-1 in PSD astrocytes stimulated NSCs differentiating into astrocytes, but inhibiting the formation of functional synapses by influencing glutamate metabolism in vitro.

Association of circulating blood HMGB1 levels with ischemic stroke: a systematic review and meta-analysis.

OBJECTIVES: Inflammation plays a key role in the pathogenesis and progression of ischemic stroke (IS). The high mobility group box 1 (HMGB1) nucleoprotein is involved in the amplification of inflammatory responses during acute ischemic injury. HMGB1 levels in patients with active disease are higher than those in healthy controls. We performed a meta-analysis to assess currently published data pertaining to circulating blood HMGB1 levels in IS and the relationship with stroke severity. METHODS: We systematically searched for studies investigating the circulating blood HMGB1 levels in patients with IS in PubMed/Medline, Embase, the Cochrane Library, Web of science and China National Knowledge Infrastructure (CNKI). Two independent researchers used the Cochrane Collaboration tools for data extraction and quality assessment. Extracted data were analyzed by Review Manager version 5.3. RESULTS: A total of 28 studies were included with a total of 4497 participants, including 2671 IS patients and 1826 matched controls. The meta-analysis revealed that compared with control, IS patients had higher circulating blood HMGB1 levels (n = 4497, standardized mean difference (SMD) = 5.70, 95%confidence interval (CI) = 4.79 to 6.62, Z = 12.23, P < 0.00001), and the HMGB1 level was positively correlated with severity (n = 507, SMD = -2.12, 95%CI = -3.41 to -0.82, Z = 3.20, P < 0.00001) and infarct volume (n = 582, 95%CI = -4.06 to -1.70, Z = 4.79, P < 0.00001). CONCLUSIONS: This meta-analysis demonstrates that circulating blood HMGB1 levels elevate in IS and higher HMGB1 levels may indicate a more serious condition.

Is topiramate effective for migraine prevention in patients less than 18 years of age? A meta-analysis of randomized controlled trials.

BACKGROUND: Mainly based on evidence of success in adults, various medications are commonly used to prevent pediatric migraines. Topiramate has been approved for migraine prevention in children as young as 12 years of age. In this meta-analysis, we aimed to assess the currently published data pertaining to the efficacy of topiramate for migraine prevention in patients less than 18 years of age. METHODS: We searched PubMed/Medline, Embase and the Cochrane Library (from inception to April 2017) for randomized controlled trials (RCTs) published in English. Two independent investigators performed data extraction and quality evaluation using the Cochrane Collaboration's tool. The data extracted were analyzed by Review Manager 5.3 software. RESULTS: A total of four RCTs matching the inclusion criteria were included, with an aggregate of 465 patients. Of these patients, 329 were included in the topiramate group, and 136 were included in the placebo group. This meta-analysis revealed that compared with placebo, topiramate failed to decrease the number of patients experiencing a ≥ 50% relative reduction in headache frequency (n = 465, RR = 1.26, 95% CI = [0.94,1.67], Z = 1.55, P = 0.12) or the number of headache days (n = 465, MD = -0.77, 95% CI = [-2.31,0.76], Z = 0.99, P = 0.32) but did reduce PedMIDAS scores (n = 205, MD = -9.02, 95% CI = [-17.34, -0.70], Z = 2.13, P = 0.03). Higher rates of side effects and adverse events in the topiramate group than in the placebo group were observed in the included trials. CONCLUSIONS: Topiramate may not achieve a more effective clinical trial endpoint than placebo in the prevention of migraines in patients less than 18 years of age, and topiramate may lead to more side effects or adverse events in the included patients.

Recombinant Human Erythropoietin Augments Neovascularization Responses in a Neonatal Rat Model of Premature Brain Damage by Phosphatidylinositol 3 Kinase/Akt Pathway.

BACKGROUND: Recombinant human-erythropoietin (rh-EPO) has therapeutic efficacy for premature infants with brain damage during the active rehabilitation and anti-inflammation. In the present study, we found that the rh-EPO was related to the promotion of neovascularization. Our aim was to investigate whether rh-EPO augments neovascularization in the neonatal rat model of premature brain damage through the phosphatidylinositol 3 kinase (PI3K)/protein kinase B (Akt) signaling pathway. METHODS: Postnatal day 5 (PD5), rats underwent permanent ligation of the right common carotid artery and were exposed to hypoxia for 2 h. All the rat pups were randomized into five groups as follows: (1) control group; (2) hypoxia-ischemic (HI) group; (3) HI + LY294002 group; (4) HI + rh-EPO group; and (5) HI + rh-EPO + LY294002 group. The phospho-Akt protein was tested 90 min after the whole operation, and CD34, vascular endothelial growth factor receptor 2 (VEGFR2), and vascular endothelial growth factor (VEGF) were also tested 2 days after the whole operation. RESULTS: In the hypoxic and ischemic zone of the premature rat brain, the rh-EPO induced CD34+ cells to immigrate to the HI brain zone (P < 0.05) and also upregulated the VEGFR2 protein expression (P < 0.05) and VEGF mRNA level (P < 0.05) through the PI3K/Akt (P < 0.05) signaling pathway when compared with other groups. CONCLUSIONS: The rh-EPO treatment augments neovascularization responses in the neonatal rat model of premature brain damage through the PI3K/Akt signaling pathway. Besides, the endogenous EPO may exist in the HI zone of rat brain and also has neovascularization function through the PI3K/Akt signaling pathway.

[Impacts of Erythropoietin on Vascular Endothelial Growth Factor Receptor 2 by the Extracellular Signal-regulated Kinase Signaling Pathway in a Neonatal Rat Model of Periventricular White Matter Damage].

OBJECTIVE: To explore the impacts of erythropoietin on vascular endothelial growth factor receptor 2 (VEGFR2) by the extracellular signal-regulated kinase (ERK) signaling pathway in a neonatal rat model of periventricular white matter damage. METHODS: All of postnatal day 4 rats were randomized into three groups: the sham group [without hypoxia-ischemia (HI)], the HI group (HI with saline administration), and the erythropoietin (EPO) group [HI with recombinant human erythropoietin (rh-EPO) administration]. Rat pups underwent permanent ligation of the right common carotid artery, followed by 6% O2 for 2 hours or sham operation and normoxic exposure. Immediately after the HI, rats received a single intraventricular injection of rh-EPO (0.6 IU/g body mass) or saline. ERK and phosphorylation-ERK were examined at 60 minutes and 90 minutes after operation, and VEGFR2 were detected at 2 and 4 days after operation by using Western blot. RESULTS: At 60 minutes and 90 minutes after operation, the proteins of phosphorylation-ERK were significantly higher in HI rats than in the sham rats and significantly higher in HI+EPO rats than in the HI rats (P<0.05). Two days after operation, VEGFR2 was not significantly different between sham and HI rats. However, the proteins of VEGFR2 were increased after administration of rh-EPO (P<0.05). Four days after operation, the proteins of VEGFR2 were significantly higher in HI rats than in the sham rats and significantly higher in HI+EPO rats than in the HI rats (P<0.05). CONCLUSION: EPO may regulate VEGFR2 expression by affecting the intracranial ERK signaling pathways.