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 shamoperation. Flow cytometry analysis, Western blotting, quantitative real-time polymerase chain reaction (qRT-PCR), coimmunoprecipitation, 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 neuropathological 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.

P rimary pontine hemorrhage (PPH) is the most devastating type of intracranial hemorrhage (ICH), with an acute mortality ranging from 30% to 60%. [1][2][3] Various factors including coma at admission, location, and volume of the hematoma were found to associate with these diverse outcomes. However, inconsistent predictors were reported when different parameters and populations were brought into analysis. [4][5][6][7] As a corollary, it would make cogent sense by combining significant factors into a grading scale to enhance predictive power and, meanwhile, provide a useful tool for physicians in decision-making when facing such patients. 8 Currently, there is no standard, widely accepted early prognostic model or clinical grading scale for outcome prediction in PPH patients. The ICH score, composed of age, Glasgow Coma Scale (GCS), infratentorial origin, intraventricular hemorrhage, and hemorrhage volume, has been widely validated in predicting acute mortality, as well as long-term functional outcome in spontaneous ICH.9,10 Easy to use though, the ICH score and its derivatives tended to deem infratentorial hemorrhage as an independent predictor of poor outcome. 11,12 Because of the small structure of the pons but severe manifestations caused by hemorrhagic impairment, the cutoff value 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 (χ 2 =1.387; P=0.846) in 30-day mortality prediction. Conclusions-The

PurposeThe application of metagenomic next-generation sequencing (mNGS) in the diagnosis of tuberculous meningitis (TBM) remains poorly characterized. Here, we retrospectively analyzed data from patients with TBM who had taken both mNGS and conventional tests including culture of Mycobacterium tuberculosis (MTB), polymerase chain reaction (PCR) and acid-fast bacillus (AFB) stain, and the sensitivity and specificity of these methods were compared.MethodsWe retrospectively recruited TBM patients admitted to the hospital between December 2015 and October 2018. The first collection of cerebrospinal fluid (CSF) samples underwent both mNGS and conventional tests. In addition, patients with bacterial/cryptococcal meningitis or viral meningoencephalitis were mNGS positive controls, and a patient with auto-immune encephalitis was an mNGS negative control.ResultsTwenty three TBM patients were classified as 12 definite and 11 clinical diagnoses, which were based on clinical manifestations, pathogen evidence, CSF parameters, brain imaging, and treatment response. The mNGS method identified sequences of Mycobacterium tuberculosis complex (MBTC) from 18 samples (18/23, 78.26%). In patients with definite TBM, the sensitivity of mNGS, AFB, PCR, and culture to detect MTB in the first CSF samples were 66.67, 33.33, 25, and 8.33%, respectively. The specificity of each method was 100%. Among the four negative mNGS cases (4/23, 17.39%), three turned out positive by repeated AFB stain. The agreement of mNGS with the total of conventional methods was 44.44% (8/18). Combination of mNGS and conventional methods increased the detection rate to 95.65%. One patient was diagnosed as complex of TBM and cryptococcal meningitis, in which AFB stain and cryptococcal antigen enzyme immunoassay were positive and the DNA of Cryptococcus neoformans was detected by mNGS.ConclusionOur study indicates that mNGS is an alternative method to detect the presence of mycobacterial DNA in CSF samples from patients with TBM and deserves to be applied as a front-line CSF test.

BackgroundSudden cardiac arrest (CA) often results in severe injury to the brain, and neuroprotection after CA has proved to be difficult to achieve. Herein, we sought to investigate the effects of metformin pretreatment on brain injury secondary to CA and cardiopulmonary resuscitation.Methods and ResultsRats were subjected to 9‐minute asphyxial CA after receiving daily metformin treatment for 2 weeks. Survival rate, neurologic deficit scores, neuronal loss, AMP‐activated protein kinase (AMPK), and autophagy activation were assessed at indicated time points within the first 7 days after return of spontaneous circulation. Our results showed that metformin pretreatment elevated the 7‐day survival rate from 55% to 85% and significantly reduced neurologic deficit scores. Moreover, metformin ameliorated CA‐induced neuronal degeneration and glial activation in the hippocampal CA1 region, which was accompanied by augmented AMPK phosphorylation and autophagy activation in affected neuronal tissue. Inhibition of AMPK or autophagy with pharmacological inhibitors abolished metformin‐afforded neuroprotection, and augmented autophagy induction by metformin treatment appeared downstream of AMPK activation.ConclusionsTaken together, our data demonstrate, for the first time, that metformin confers neuroprotection against ischemic brain injury after CA/cardiopulmonary resuscitation by augmenting AMPK‐dependent autophagy activation.

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.

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 ischemiaactivated 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.

BackgroundPrediction of extubation failure, particularly in neurocritical patients, is unique and controversial. We conducted a systematic review and meta-analysis to identify the risk factors for extubation failure in these patients.MethodsA literature search of databases (MEDLINE, EMBASE, the Cochrane Library, and Web of Science) was performed up to August of 2013 to identify trials that evaluated extubation failure predictors. Included trials were either prospective or retrospective cohort studies.ResultsNine studies involving 928 participants were included. The systematic review and meta-analysis revealed that the following were predictive for extubation failure: pneumonia, atelectasis, mechanical ventilation of >24 h, a low Glasgow Coma Scale score (7–9T) (OR = 4.96, 95% CI = 1.61–15.26, P = 0.005), the inability to follow commands (OR = 2.07, 95% CI = 1.15–3.71, P = 0.02), especially the command to close the eyes, thick secretion, and no intact gag reflex. Meanwhile, the following were not predictive for extubation failure: sex, secretion volume, coughing upon suctioning, and the inability to follow one command among showing two fingers, wiggling the toes, or coughing on command. Additionally, some traditional weaning parameters were shown to poorly predict extubation failure in neurocritical patients.ConclusionsBesides pneumonia, atelectasis, and the duration of mechanical ventilation, other factors that should be taken into consideration in the prediction of extubation failure when neurocritical patients are weaned from tracheal intubation include neurologic abilities (Glasgow Coma Scale score and following commands), the secretion texture, and the presence of a gag reflex.

In predicting 30-day mortality in patients with PPH, SAPS II has the best calibration, while APACHE II has the highest discrimination. The ICH score, which is easier and simpler to calculate, should be modified for PPH.