Glymphatic System Impairment Contributes to the Formation of Brain Edema After Ischemic Stroke.

BACKGROUND: Blood-brain barrier damage has traditionally been considered to determine the occurrence and development of poststroke brain edema, a devastating and life-threatening complication. However, no treatment strategy targeting blood-brain barrier damage has been proven clinically effective in ameliorating brain edema. METHODS: In mice with stroke models induced by transient middle cerebral artery occlusion (MCAO), the changes in glymphatic system (GS) function impairment were detected by ex vivo fluorescence imaging, 2-photon in vivo imaging, and magnetic resonance imaging within 1 week after MCAO, and the effects of GS impairment and recovery on the formation and resolution of brain edema were evaluated. In addition, in patients with ischemic stroke within 1 week after onset, changes in GS function and brain edema were also observed by magnetic resonance imaging. RESULTS: We found that the extravasation of protein-rich fluids into the brain was not temporally correlated with edema formation after MCAO in mice, as brain edema reabsorption preceded blood-brain barrier closure. Strikingly, the time course of edema progression matched well with the GS dysfunction after MCAO. Pharmacological enhancement of the GS function significantly alleviated brain edema developed on day 2 after MCAO, accompanied by less deposition of Aß (amyloid-ß) and better cognitive function. Conversely, functional suppression of the GS delayed the absorption of brain edema on day 7 after MCAO. Moreover, patients with ischemic stroke revealed a consistent trend of GS dysfunction after reperfusion as MCAO mice, which was correlated with the severity of brain edema and functional outcomes. CONCLUSIONS: GS is a key contributor to the formation of brain edema after ischemic stroke, and targeting the GS may be a promising strategy for treating brain edema in ischemic stroke. REGISTRATION: URL: https://www.chictr.org.cn/showproj.html?proj=162857; Unique identifier: NFEC-2019-189.

An end-to-end multi-task system of automatic lesion detection and anatomical localization in whole-body bone scintigraphy by deep learning.

SUMMARY: Limited by spatial resolution and visual contrast, bone scintigraphy interpretation is susceptible to subjective factors, which considerably affects the accuracy and repeatability of lesion detection and anatomical localization. In this work, we design and implement an end-to-end multi-task deep learning model to perform automatic lesion detection and anatomical localization in whole-body bone scintigraphy. A total of 617 whole-body bone scintigraphy cases including anterior and posterior views were retrospectively analyzed. The proposed semi-supervised model consists of two task flows. The first one, the lesion segmentation flow, received image patches and was trained in a supervised way. The other one, skeleton segmentation flow, was trained on as few as five labeled images in conjunction with the multi-atlas approach, in a semi-supervised way. The two flows joint in their encoder layers so each flow can capture more generalized distribution of the sample space and extract more abstract deep features. The experimental results show that the architecture achieved the highest precision in the finest bone segmentation task in both anterior and posterior images of whole-body scintigraphy. Such an end-to-end approach with very few manual annotation requirement would be suitable for algorithm deployment. Moreover, the proposed approach reliably balances unsupervised labels construction and supervised learning, providing useful insight for weakly labeled image analysis. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

White Matter Hyperintensity is Associated with Malignant Cerebral Edema in Ischemic Stroke Treated with Thrombectomy.

BACKGROUND: White matter hyperintensity (WMH) burden may lead to poor clinical outcomes after endovascular thrombectomy (EVT). But the relationship between WMH burden and cerebral edema (CED) is unclear. PURPOSE: To examine the association between WMH burden and CED and functional outcome in patients treated with EVT. STUDY TYPE: Retrospective. SUBJECT: 344 patients with acute anterior circulation large-vessel occlusion stroke who received EVT at two comprehensive stroke centers. Mean age was 62.6 ± 11.6 years and 100 patients (29.1%) were female. FIELD STRENGTH/SEQUENCE: 3T, including diffusion-weighted imaging and fluid-attenuated inversion recovery (FLAIR) images. ASSESSMENT: The severity of WMH was evaluated using the Fazekas scale on a FLAIR sequence before EVT. The severity of CED was assessed using CED score (three for malignant cerebral edema [MCE]) and net water uptake (NWU)/time on post-EVT cranial CT. The impact of WMH burden on MCE, NWU/time, and 3-month poor outcome (modified Rankin scale >2) after EVT were assessed. STATISTICAL TESTS: Pearson's chi-squared test, Fisher exact test, 2-tailed t test, Mann-Whitney U test, multivariable logistic regression, multivariate regression analysis, Sobel test. A P value <0.05 was considered statistically significant. RESULTS: WMH burden was not significantly associated with MCE and parenchymal hemorrhage (PH) in the whole population (P = 0.072; P = 0.714). WMH burden was significantly associated with an increased risk of MCE (OR, 1.550; 95% CI, 1.128-2.129), higher NWU/time (Coefficient, 0.132; 95% CI, 0.012-0.240), and increased risk of 3-month poor outcome (OR, 1.434; 95% CI, 1.110-1.853) in the subset of patients without PH. Moreover, the connection between WMH burden and poor outcome was partly mediated by CED in patients without PH (regression coefficient changed by 29.8%). DATA CONCLUSION: WMH burden is associated with CED, especially MCE, and poor outcome in acute ischemic stroke patients treated with EVT. The association between WMH burden and poor outcome may partly be attributed to postoperative CED. TECHNICAL EFFICACY: Stage 5.

Effect of a Declined Plasma Concentration of Valproic Acid Induced by Meropenem on the Antiepileptic Efficacy of Valproic Acid.

OBJECTIVE: This study aimed to indicate whether a declined plasma concentration of valproic acid (VPA) induced by co-administration of meropenem (MEPM) could affect the antiepileptic efficacy of VPA. METHODS: We retrospectively reviewed data of hospitalized patients who were diagnosed with status epilepticus or epilepsy between 2010 and 2019. Patients co-administered VPA and MEPM during hospitalization were screened and assigned to the exposure group, while those co-administerd VPA and other broad-spectrum antibiotics were allocated to the control group. RESULTS: The exposure group and control group included 50 and 11 patients, respectively. With a similar dosage of VPA, the plasma concentration of VPA significantly decreased during co-administration (24.6 ± 4.3 µg/mL) compared with that before co-administration (88.8 ± 13.6 µg/mL, p < 0.0001), and it was partly recovered with the termination of co-administration (39.8 ± 13.2 µg/mL, p = 0.163) in the exposure group. The inverse probability of treatment weighting estimated the treatment efficacy via changes in seizure frequency, seizure duration, and concomitant use of antiepileptic drugs, which were not significantly different between the exposure and control groups. In the exposure group, there was no significant differences in seizure frequency between the periods of before-during and before-after (p = 0.074 and 0.153, respectively). Seizure duration during VPA-MEPM co-administration was not significantly different from that before co-administration (p = 0.291). CONCLUSIONS: In this study, the reduced plasma concentration of VPA induced by the co-administration of MEPM did not affect the antiepileptic efficacy of VPA. This conclusion should be interpreted with caution, and more research is warranted. TRIAL REGISTRATION: Chinese Clinical Trial Registry: ChiCTR2000034567. Registered on 10 July 2020.

Three-Dimensional Digital Reconstruction of the Cerebellar Cortex: Lobule Thickness, Surface Area Measurements, and Layer Architecture.

The cerebellum is ontogenetically one of the first structures to develop in the central nervous system; nevertheless, it has been only recently reconsidered for its significant neurobiological, functional, and clinical relevance in humans. Thus, it has been a relatively under-studied compared to the cerebrum. Currently, non-invasive imaging modalities can barely reach the necessary resolution to unfold its entire, convoluted surface, while only histological analyses can reveal local information at the micrometer scale. Herein, we used the BigBrain dataset to generate area and point-wise thickness measurements for all layers of the cerebellar cortex and for each lobule in particular. We found that the overall surface area of the cerebellar granular layer (including Purkinje cells) was 1,732 cm2 and the molecular layer was 1,945 cm2. The average thickness of the granular layer is 0.88 mm (± 0.83) and that of the molecular layer is 0.32 mm (± 0.08). The cerebellum (both granular and molecular layers) is thicker at the depth of the sulci and thinner at the crowns of the gyri. Globally, the granular layer is thicker in the lateral-posterior-inferior region than the medial-superior regions. The characterization of individual layers in the cerebellum achieved herein represents a stepping-stone for investigations interrelating structural and functional connectivity with cerebellar architectonics using neuroimaging, which is a matter of considerable relevance in basic and clinical neuroscience. Furthermore, these data provide templates for the construction of cerebellar topographic maps and the precise localization of structural and functional alterations in diseases affecting the cerebellum.

Flufenamic acid improves survival and neurologic outcome after successful cardiopulmonary resuscitation in mice.

BACKGROUND: Brain injury is the main cause of high mortality and disability after successful cardiopulmonary resuscitation (CPR) from sudden cardiac arrest (CA). The transient receptor potential M4 (TRPM4) channel is a novel target for ameliorating blood-brain barrier (BBB) disruption and neuroinflammation. Herein, we tested whether flufenamic acid (FFA), which is reported to block TRPM4 with high potency, could confer neuroprotection against brain injury secondary to CA/CPR and whether its action was exerted by blocking the TRPM4 channel. METHODS: Wild-type (WT) and Trpm4 knockout (Trpm4-/-) mice subjected to 10-min CA/CPR were randomized to receive FFA or vehicle once daily. Post-CA/CPR brain injuries including neurologic deficits, survival rate, histological damage, edema formation, BBB destabilization and neuroinflammation were assessed. RESULTS: In WT mice subjected to CA/CPR, FFA was effective in improving survival and neurologic outcome, reducing neuropathological injuries, attenuating brain edema, lessening the leakage of IgG and Evans blue dye, restoring tight junction protein expression and promoting microglia/macrophages from the pro-inflammatory subtype toward the anti-inflammatory subtype. In comparison to WT mice, Trpm4-/- mice exhibited less neurologic deficiency, milder histological impairment, more BBB integrity and more anti-inflammatory microglia/macrophage polarization. As expected, FFA did not provide a benefit of superposition compared with vehicle in the Trpm4-/- mice after CA/CPR. CONCLUSIONS: FFA mitigates BBB breach and modifies the functional status of microglia/macrophages, thereby improving survival and neurologic deficits following CA/CPR. The neuroprotective effects occur at least partially by interfering with the TRPM4 channel in the neurovascular unit. These results indicate the significant clinical potential of FFA to improve the prognosis for CA victims who are successfully resuscitated.

Dynamic changes of neutrophil-to-lymphocyte ratio in brain-dead donors and delayed graft function in kidney transplant recipients.

OBJECTIVES: Neutrophil-to-lymphocyte ratio (NLR) is a simple parameter implying the inflammatory status. We aimed to explore the association of brain-dead donor NLR change with delayed graft function (DGF) in kidney transplant recipients. METHODS: We retrospectively analyzed the data on 102 adult brain-dead donors and their corresponding 199 kidney transplant recipients (2018 - 2021). We calculated ΔNLR by subtracting the NLR before evaluating brain death from the preoperative NLR. Increasing donor NLR was defined as ΔNLR > 0. RESULTS: Forty-four (22%) recipients developed DGF after transplantation. Increasing donor NLR was significantly associated with the development of DGF in recipients (OR 2.8, 95% CI 1.2 - 6.6; p = .018), and remained significant (OR 2.6, 95% CI 1.0 - 6.4; p = .040) after adjustment of confounders including BMI, hypertension, diabetes, and the occurrence of cardiac arrest. When acute kidney injury (AKI) was included in the multivariable analysis, increasing donor NLR lost its independent correlation with DGF, while AKI remained an independent risk factor of recipient DGF (OR 4.5, 95% CI 2.7 - 7.6; p < .001). The area under the curve of combined increasing NLR and AKI in donors (0.873) for predicting DGF was superior to increasing donor NLR (0.625, p = .015) and AKI alone (0.859, p < .001). CONCLUSIONS: Dynamic changes of donor NLR are promising in predicting post-transplant DGF. It will assist clinicians in the early recognition and management of renal graft dysfunction. Validation of this new biomarker in a large study is needed.

NLRP3 inflammasome-mediated microglial pyroptosis is critically involved in the development of post-cardiac arrest brain injury.

BACKGROUND: Brain injury is the leading cause of death and disability in survivors of cardiac arrest, where neuroinflammation is believed to play a pivotal role, but the underlying mechanism remains unclear. Pyroptosis is a pro-inflammatory form of programmed cell death that triggers inflammatory response upon infection or other stimuli. This study aims to understand the role of microglial pyroptosis in post-cardiac arrest brain injury. METHODS: Sprague-Dawley male rats underwent 10-min asphyxial cardiac arrest and cardiopulmonary resuscitation or sham-operation. Flow cytometry analysis, Western blotting, quantitative real-time polymerase chain reaction (qRT-PCR), co-immunoprecipitation, and immunofluorescence were used to evaluate activated microglia and CD11b-positive leukocytes after cardiac arrest and assess inflammasome activation and pyroptosis of specific cellular populations. To further explore the underlying mechanism, MCC950 or Ac-YVAD-cmk was administered to block nod-like receptor family protein 3 (NLRP3) or caspase-1, respectively. RESULTS: Our results showed that, in a rat model, successful resuscitation from cardiac arrest resulted in microglial pyroptosis and consequential inflammatory infiltration which was mediated by the activation of NLRP3 inflammasome. Targeting NLRP3 and caspase-1, the executor of pyroptosis, with selective inhibitors MCC950 and Ac-YVAD-cmk treatment significantly prevented microglial pyroptosis, reduced infiltration of leukocytes, improved neurologic outcome, and alleviated neuro-pathological damages after cardiac arrest in modeling rats. CONCLUSIONS: This study demonstrates that microglial pyroptosis mediated by NLRP3 inflammasome is critically involved in the pathogenesis of post-cardiac arrest brain injury and provides a new therapeutic strategy.

Biomarkers of Unfavorable Outcome in Acute Ischemic Stroke Patients with Successful Recanalization by Endovascular Thrombectomy.

BACKGROUND: We aimed to identify plasma markers of unfavorable outcomes for patients with acute ischemic stroke (AIS) after recanalization by endovascular thrombectomy (EVT). METHODS: From November 2017 to May 2019, we prospectively collected 61 AIS patients due to anterior large vessel occlusion who achieved recanalization by EVT. Plasma samples were obtained between 18 and 24 h after recanalization. Unfavorable outcomes included futile recanalization at 90 days and overall early complications within 7 days after EVT. RESULTS: After adjustment for age and initial National Institute of Health Stroke Scale (NIHSS), matrix metalloproteinase-9 (MMP-9), tenascin-C, thioredoxin, ADAMTS13, and gelsolin were independently associated with both futile recanalization and overall early complications significantly (all p < 0.05), while C-reactive protein (CRP) was independently associated with overall early complications (p = 0.031) but at the limit of significance for futile recanalization (p = 0.051). The baseline clinical model (BCM) (including age and initial NIHSS) demonstrated discriminating ability to indicate futile recanalization (area under the curve [AUC] 0.807, 95% confidence interval [CI] 0.693-0.921) and overall early complications (AUC 0.749, 95% CI 0.611-0.887). BCM+MMP-9+thioredoxin enhanced discrimination (AUC 0.908, 95% CI 0.839-0.978, p = 0.043) and reclassification (net reclassification improvement [NRI] 67.2%, p < 0.001) to indicate futile recanalization. With respect to overall early complications, BCM+MMP-9+tenascin-C, BCM+MMP-9+CRP, BCM+MMP-9+ADAMTS13, BCM+tenascin-C+ADAMTS13, and BCM+CRP+ADAMTS13, all improved discrimination (AUC [95% CI]: 0.868 [0.766-0.970], 0.882 [0.773-0.990], 0.886 [0.788-0.984], 0.880 [0.783-0.977], and 0.863 [0.764-0.962], respectively, all p < 0.05 by the DeLong method) and reclassification (NRI 59.1%, 71.8%, 51.1%, 67.4%, and 38.3%, respectively, all p < 0.05). CONCLUSIONS: The increased levels of MMP-9, tenascin-C, CRP, thioredoxin, and decreased levels of ADAMTS13 and gelsolin were independent predictors of futile recanalization in AIS patients after recanalization by EVT.

Dynamic cerebral autoregulation is an independent outcome predictor of acute ischemic stroke after endovascular therapy.

BACKGROUND: Endovascular therapy (EVT) is increasingly used to improve cerebral reperfusion after moderate-to-severe acute ischemic stroke (AIS). However, the influence of hemodynamic factors on clinical outcome is still unclear after EVT. Dynamic cerebral autoregulation (dCA) is an important brain reserve mechanism and is impaired after AIS. This study aimed to explore the role of dCA in predicting the outcome of AIS patients after EVT. METHODS: AIS patients with severe stenosis/occlusion of unilateral middle cerebral artery (MCA) or internal carotid and treatment with EVT were enrolled to receive dCA examinations at the 24 h, 72 h and 7th day after stroke onset. Healthy volunteers were also recruited as controls. DCA was recorded from spontaneous fluctuations of blood pressure and MCA flow velocity. Transfer function analysis was used to derive dCA parameters, including phase difference (PD) and coherence in the low-frequency range (0.06-0.12 Hz). The clinical outcome was measured using the modified Rankin Scale (mRS) at 90 days after onset. Multivariate logistic regression was performed to reveal the correlation between dCA and clinical outcomes. The receiver operation characteristics (ROC) curve was performed to determine the cut-off point of PD. RESULTS: A total of 62 AIS patients and 77 healthy controls were included. Compared with controls, dCA were impaired bilaterally till to 7th day after onset in patients, presenting as much lower PD value on the ipsilateral side. During follow-up, we found that PD on the ipsilateral side at 24 h after onset was significantly lower in patients with unfavourable outcome (n = 41) than those with favourable outcome (n = 21), even after adjustment of confounding factors (p = 0.009). ROC curve analysis revealed that PD < 26.93° was an independent predictor of unfavourable-outcome. CONCLUSION: In AIS patients after EVT, dCA was impaired on both sides over the first 7 days. PD on the ipsilateral side at 24 h after onset is an independent unfavourable-outcome predictor for AIS after EVT.

Safety and efficacy of glibenclamide combined with rtPA in acute cerebral ischemia with occlusion/stenosis of anterior circulation (SE-GRACE): study protocol for a randomized controlled trial.

BACKGROUND: Thrombolysis with recombinant tissue plasminogen activator (rtPA) improves outcome for patients with acute ischemic stroke (AIS), but many of them still have substantial disability. Glibenclamide (US adopted name, glyburide), a long-acting sulfonylurea, shows promising result in treating AIS from both preclinical and clinical studies. This study investigates the safety and efficacy of glibenclamide combined with rtPA in treating AIS patients. METHODS: This is a prospective, randomized, double-blind, placebo-controlled, multicenter trial with an estimated sample size of 306 cases, starting in January 2018. Patients aged 18 to 74 years, presented with a symptomatic anterior circulation occlusion with a deficit on the NIHSS of 4 to 25 points and treated with intravenous rtPA within the first 4.5 h of their clinical onsets, are eligible for participation in this study. The target time from the onset of symptoms to receive the study drug is of 10 h. Subjects are randomized 1: 1 to receive glibenclamide or placebo with a loading dose of 1.25 mg, followed by 0.625 mg every 8 h for total 5 days. The primary efficacy endpoint is 90-day good outcome, measured as modified Rankin Scale of 0 to 2. Safety outcomes are all-cause 30-day mortality and early neurological deterioration, with a focus on cardiac- and glucose-related serious adverse events. DISCUSSION: This study will provide valuable information about the safety and efficacy of oral glibenclamide for AIS patients treated with rtPA. This would bring benefits to a large number of patients if the agent is proved to be effective. TRIAL REGISTRATION: The trial was registered on September 14th 2017 at www.clinicaltrials.gov having identifier NCT03284463. Registration was performed before recruitment was initiated.

Glutamic acid decarboxylase antibodies in neurocritical patients: a culprit or a bystander?

BACKGROUND: Glutamic acid decarboxylase (GAD) is an intracellular enzyme, which is widely expressed in central nervous system (CNS), pancreas, and other organs. GAD antibodies (GAD-Abs) are linked to various neurological disorders. However, the significance of GAD-Abs in neurocritical patients is undetermined. MATERIALS AND METHODS: Patients with serologically positive GAD-Abs and requiring neurocritical care were included. The clinical, laboratory, and outcome data were retrospectively collected. RESULTS: We included 9 patients with serologically positive GAD-Abs. Clinical manifestations involved both CNS and peripheral nervous system (PNS). Six (66.7%) patients had other specific autoimmune antibodies. Non-specific autoimmune responses were observed in 8 (88.9%) patients. All patients clinically responded well to immunotherapy. The titers of GAD-Abs decreased in 7 (77.8%) patients but remained unchanged in the other 2 patients. One (11.1%) patient awoke before the negative conversion of GAD-Abs, and 3 (33.3%) patients remained unconscious and/or under mechanical ventilation for several weeks after the vanishing of GAD-Abs. CONCLUSIONS: Most neurocritical patients with serologically positive GAD-Abs had other specific autoimmune antibodies. All patients responded well to immunotherapy, but not parallel to the titers of GAD-Abs. These results indicated that GAD-Abs might be more a bystander than a culprit in neurocritical patients, suggesting that an underlying autoimmune disease should be explored.

Hotair mediates tumorigenesis through recruiting EZH2 in colorectal cancer.

Long noncoding RNAs (lncRNA)  have been demonstrated to extensively participate in a wide spectrum of biological activities ranging from embryogenesis and cancer progression. HOX transcript antisense RNA (Hotair), an lncRNA located in the HOXC locus, has been reported to play an important role in carcinogenesis. As a well-known oncogene, it potentiates cancer metastasis and tumor progression. And it also serves as a biomarker for poor prognosis and tumor recurrence. In this study, Hotair was found to be upregulated in colorectal cancer (CRC) cells and clinical specimens. Further investigation showed that knockdown of Hotair dramatically suppressed cell proliferation and colony formation, suggesting that Hotair may stimulate tumorigenesis of CRC. The enhancer of zeste homolog 2 (EZH2), a regulator of epigenetic modification, was upregulated in CRC cells and clinical samples. And the silence of EZH2 significantly suppressed cell viability and colony formation. Furthermore, the RNA immunoprecipitation assay revealed that Hotair directly bound EZH2 in CRC cells. In conclusion, Hotair mediated tumorigenesis via recruiting EZH2, which might shed light on the development of a novel therapeutic approach for patients with CRC.

Exploratory analysis of oral glibenclamide in acute ischemic stroke.

OBJECTIVES: Intravenous glibenclamide (GBC) exerts neuroprotection in both preclinical and preliminary clinical studies. This study explored the safety and potential efficacy of oral GBC in patients with acute hemispheric infarction. MATERIALS & METHODS: During January 2017 and August 2017, adult volunteers were recruited to receive oral GBC treatment, if they presented with an acute anterior ischemic stroke and a National Institute of Health Stroke Score of ≥8. Controls were those who met the above inclusion criteria and had not been on GBC or other sulfonylureas prior to stroke or after hospitalization. Propensity score matching (PSM) was performed to balance baseline characteristics. The primary endpoint was the score on the modified Rankin Scale (mRS) at 6 months. RESULTS: We included 213 patients in the unmatched cohort (20 in the GBC group and 193 in the control group) and 40 patients (20 in each group) in the matched cohort. In both cohorts, GBC treatment did not increase the risks of early death, hypoglycemia, and early neurological deterioration. Although GBC did not substantially improve 6-month functional outcome that measured in shift analysis of mRS, a slight trend toward less severe disability and death (mRS 5-6) was observed. In the matched cohort, GBC treatment was associated with lighter brain edema, when CED score was used for evaluation. CONCLUSIONS: In this study, oral GBC is safe in treating acute hemispheric infarction and might have potential in preventing brain edema and consequential severe disability and death. An adequately powered and randomized trial is warranted.

Glibenclamide Prevents Water Diffusion Abnormality in the Brain After Cardiac Arrest in Rats.

BACKGROUND: Glibenclamide (GBC) improves neurological outcome after cardiac arrest (CA) in rats. In this study, we sought to elucidate the mechanism responsible for the neuroprotective effects of GBC by using a high-field MRI system. METHODS: Male Sprague-Dawley rats were subjected to 10-min asphyxial CA followed by cardiopulmonary resuscitation (CPR). Diffusion-weighted imaging (DWI) as well as conventional T2-weighted imaging was conducted prior to CA and at 24, 48, and 72 h after resuscitation. Afterward, histological examination was performed. RESULTS: Twelve rats were randomized to receive GBC (n = 6) or vehicle (n = 6) at 15 min after return of spontaneous circulation, while four rats were set as sham control. Rats that underwent CA/CPR and received vehicle exhibited distinct neurological deficit, which was alleviated by GBC treatment. Marked water diffusion abnormality as demonstrated by hyperintense DWI in vulnerable regions of the brain was detected after CA/CPR, with the most prominent hyperintense DWI observed in the hippocampal CA1 region at 72 h. Consistently, histological examination revealed neuronal swelling, dendritic injury, and activation of astrocytes and microglia in the hippocampal CA1 region in vehicle-treated rats. Correlation analysis revealed that the ADC values in the hippocampus were significantly correlated with the histological findings (all p < 0.05). CONCLUSION: These results suggest that the neuroprotective effects of GBC after CA was exerted, as least in part, through prevention of water diffusion abnormality, namely brain edema.

Development and Validation of a Grading Scale for Primary Pontine Hemorrhage.

BACKGROUND AND PURPOSE: We aimed to develop and validate a grading scale for predicting 30-day mortality and 90-day functional outcome in patients with primary pontine hemorrhage (PPH). METHODS: We retrospectively reviewed records of consecutive patients with first-ever pontine hemorrhage from 3 teaching hospitals between 2005 and 2012. Independent factors associated with 30-day mortality were identified by logistic regression to establish a risk stratification scale, named the new PPH score. For validation of the new PPH score, we prospectively recruited subjects from 10 units between December 2014 and November 2015. The performance of the new PPH score was presented as discrimination and calibration, measured by area under the curve of the receiver operating characteristic and Hosmer-Lemeshow goodness-of-fit, respectively. RESULTS: Data of 171 patients were available for scale development. The new PPH score consisted of 2 independent factors with individual points assigned as follows: Glasgow Coma Scale score 3 to 4 (=2 points), 5 to 7 (=1 point), and 8 to 15 (=0 point); PPH volume >10 mL (=2 points), 5 to 10 mL (=1 point), and <5 mL (=0 point). An independent cohort of 98 patients was applied as an external validation of the new PPH score. Results showed that the new PPH score was discriminative in predicting both 30-day mortality (area under the curve, 0.902) and 90-day good outcome (area under the curve, 0.927). Furthermore, the new PPH score revealed a good calibration (χ2=1.387; P=0.846) in 30-day mortality prediction. CONCLUSIONS: The new PPH score is simple and reliable in predicting short-term and long-term outcome for PPH patients. CLINICAL TRIAL REGISTRATION: URL: http://www.chictr.org.cn. Unique identifier: ChiCTR-OOC-14005533.

Preconditioning with recombinant high-mobility group box 1 induces ischemic tolerance in a rat model of focal cerebral ischemia-reperfusion.

Preconditioning with ligands of toll-like receptors (TLRs) is a powerful neuroprotective approach whereby a low dose of stimulus confers significant protection against subsequent substantial brain damage by reprogramming the ischemia-activated TLRs signaling. Herein, we aim to explore whether preconditioning with recombinant high-mobility group box 1 (rHMGB1), one of the TLRs ligands, decreases cerebral ischemia-reperfusion injury (IRI). Rats were intracerebroventricularly pretreated with rHMGB1, 1 or 3 days before induction of middle cerebral artery occlusion. Results showed that preconditioning with rHMGB1 1 day, but not 3 days, prior to ischemia dramatically reduced neurological deficits, infarct size, brain swelling, cell apoptosis, and blood-brain barrier permeability. Interleukin-1R-associated kinase-M (IRAK-M), a critical negative regulator of TLRs signaling, was robustly increased in response to brain IRI and was further elevated by rHMGB1 pretreatment, indicating its role associated with the rHMGB1 preconditioning-mediated ischemic tolerance. In vitro and in vivo assays indicated that the induced IRAK-M expression was localized in microglia. In addition, TLR4 specific inhibitor TAK-242 abolished the neuroprotective effects and the induction of IRAK-M offered by rHMGB1 preconditioning. Collectively, our study demonstrates that rHMGB1 preconditioning is neuroprotective during cerebral IRI, which is associated with activated TLR4/IRAK-M signaling in microglia. We found that high-mobility group box 1 (HMGB1) pretreatment conditioned the brain against subsequent ischemia-reperfusion injury. We propose the following mechanism for HMGB1 preconditioning-mediated ischemic tolerance: through toll-like receptor TLR4, HMGB1 preconditioning magnifies the up-regulation of interleukin-1R-associated kinase-M (IRAK-M) induced by ischemia-reperfusion in microglia, resulting in the decreased phosphorylation of IRAK-1. These findings are helpful in understanding the endogenous mechanisms that counteract ischemic insults.

Prolonged hypothermia exposure diminishes neuroprotection for severe ischemic-hypoxic primary neurons.

This study aimed to identify optimal mild hypothermic (MH) condition that would provide the best protection for neuronal cells undergoing severe ischemia and hypoxia. We also sought to determine if longer exposure to mild hypothermia would confer greater protection to severe ischemia and hypoxia in these cells. We designed a primary neuronal cell model for severe glucose and oxygen deprivation/reoxygenation (OGD/R) to simulate the hypoxic-ischemic condition of patients with severe stroke, trauma, or hypoxic-ischemic encephalopathy. We evaluated the viability of these neurons following 3 h of OGD/R and variable MH conditions including different temperatures and durations of OGD/R exposure. We further explored the effects of the optimal MH condition on several parts which are associated with mitochondrial apoptosis pathway: intracellular calcium, reactive oxygen species (ROS), and mitochondrial transmembrane potential (MTP). The results of this study showed that the apoptosis proportion (AP) and cell viability proportion (CVP) after OGD/R significantly varied depending on which MH condition cells were exposed to (p < 0.001). Further, our findings showed that prolonged MH reduced the neuroprotection to AP and CVP. We also determined that the optimal MH conditions (34 °C for 4.5 h) reduced intracellular calcium, ROS, and recovered MTP. These findings indicate that there is an optimal MH treatment strategy for severely hypoxia-ischemic neurons, prolonged duration might diminish the neuroprotection, and that MH treatment likely initiates neuroprotection by inhibiting the mitochondrial apoptosis pathway.

Glibenclamide Improves Survival and Neurologic Outcome After Cardiac Arrest in Rats.

OBJECTIVES: Glibenclamide confers neuroprotection in animal models as well as in retrospective clinical studies. This study determines whether glibenclamide improves outcome after cardiac arrest in rats. DESIGN: Prospective randomized laboratory study. SETTING: University research laboratory. SUBJECTS: Male Sprague-Dawley rats (n = 126). INTERVENTIONS: Rats successfully resuscitated from 8-minute asphyxial cardiac arrest were randomized to glibenclamide or vehicle group. Rats in the glibenclamide group were intraperitoneally administered glibenclamide with a loading dose of 10 µg/kg at 10 minutes and a maintenance dose of 1.2 µg at 6, 12, 18, and 24 hours after return of spontaneous circulation, whereas rats in the vehicle group received equivalent volume of vehicle solution. MEASUREMENTS AND MAIN RESULTS: Survival was recorded every day, and neurologic deficit scores were assessed at 24, 48, and 72 hours and 7 days after return of spontaneous circulation (n = 22 in each group). Results showed that glibenclamide treatment increased 7-day survival rate, reduced neurologic deficit scores, and prevented neuronal loss in the hippocampal cornu ammonis 1 region. To investigate the neuroprotective effects of glibenclamide in acute phase, we observed neuronal injury at 24 hours after return of spontaneous circulation and found that glibenclamide significantly decreased the rate of neuronal necrosis and apoptosis. In addition, glibenclamide reduced the messenger RNA expression of tumor necrosis factor-α and monocyte chemoattractant protein-1 in the cortex after return of spontaneous circulation. Furthermore, the sulfonylurea receptor 1 and transient receptor potential M4 heteromers, the putative therapeutic targets of glibenclamide, were up-regulated after cardiac arrest and cardiopulmonary resuscitation, indicating that they might be involved in neuroprotective effect of glibenclamide. CONCLUSIONS: Glibenclamide treatment substantially improved survival and neurologic outcome throughout a 7-day period after return of spontaneous circulation. The salutary effects of glibenclamide were associated with suppression of neuronal necrosis and apoptosis, as well as inflammation in the brain.