Intracranial Pressure during External Ventricular Drainage Weaning Is an Outcome Predictor of Traumatic Brain Injury.

External ventricular drainage (EVD) is widely used in patients with a traumatic brain injury (TBI). However, the EVD weaning trial protocol varies and insufficient studies focus on the intracranial pressure (ICP) during the weaning trial. We aimed to establish the relationship between ICP during an EVD weaning trial and the outcomes of TBI. We enrolled 37 patients with a TBI with an EVD from July 2018 to September 2019. Among them, 26 were allocated to the favorable outcome group and 11 to the unfavorable outcome group (death, post-traumatic hydrocephalus, persistent vegetative state, and severe disability). Groups were well matched for sex, pupil reactivity, admission Glasgow Coma Scale score, Marshall computed tomography score, modified Fisher score, intraventricular hemorrhage, EVD days, cerebrospinal fluid output before the weaning trial, and the complications. Before and during the weaning trial, we recorded the ICP at 1-hour intervals to calculate the mean ICP, delta ICP, and ICP burden, which was defined as the area under the ICP curve. There were significant between-group differences in the age, surgery types, and intensive care unit days (p = 0.045, p = 0.028, and p = 0.004, respectively). During the weaning trial, 28 (75.7%) patients had an increased ICP. Although there was no significant difference in the mean ICP before and during the weaning trial, the delta ICP was higher in the unfavorable outcome group (p = 0.001). Moreover, patients who experienced death and hydrocephalus had a higher ICP burden, which was above 20 mmHg (p = 0.016). Receiver operating characteristic analyses demonstrated the predictive ability of these variables (area under the curve [AUC] = 0.818 [p = 0.002] for delta ICP and AUC = 0.758 [p = 0.038] for ICP burden > 20 mmHg). ICP elevation is common during EVD weaning trials in patients with TBI. ICP-related parameters, including delta ICP and ICP burden, are significant outcome predictors. There is a need for larger prospective studies to further explore the relationship between ICP during EVD weaning trials and TBI outcomes.

Depletion of Microglia Attenuates Dendritic Spine Loss and Neuronal Apoptosis in the Acute Stage of Moderate Traumatic Brain Injury in Mice.

Microglia are the primary immune cells in the central nervous system and undergo significant morphological and transcriptional changes after traumatic brain injury (TBI). However, their exact contribution to the pathogenesis of TBI is still debated and remains to be elucidated. In the present study, thy-1 GFP mice received a colony-stimulating factor 1 receptor inhibitor (PLX3397) for 21 consecutive days, then were subjected to moderate fluid percussion injury (FPI). Brain samples were collected at 1 day and 3 days after FPI for flow cytometry analysis, immunofluorescence, dendrite spine quantification, terminal deoxynucleotidyl transferase dUTP nick end labeling assay, and Western blot. We found that PLX3397 treatment significantly attenuated the percentages of resident microglia and infiltrated immune cells. Depletion of microglia promoted neurite outgrowth, preserved dendritic spines and reduced total brain cell and neuronal apoptosis after FPI, which was accompanied by decreased the protein levels of endoplasmic reticulum stress marker proteins, C/EBP-homologous protein and inositol-requiring kinase 1α. Taken together, these findings suggest that microglial depletion may exert beneficial effects in the acute stage of FPI.

Acute histopathological responses and long-term behavioral outcomes in mice with graded controlled cortical impact injury.

While animal models of controlled cortical impact often display short-term motor dysfunction after injury, histological examinations do not show severe cortical damage. Thus, this model requires further improvement. Mice were subjected to injury at three severities using a Pin-Point™-controlled cortical impact device to establish secondary brain injury mouse models. Twenty-four hours after injury, hematoxylin-eosin staining, Fluoro-Jade B histofluorescence, and immunohistochemistry were performed for brain slices. Compared to the uninjured side, we observed differences of histopathological findings, neuronal degeneration, and glial cell number in the CA2 and CA3 regions of the hippocampus on the injured side. The Morris water maze task and beam-walking test verified long-term (14-28 days) spatial learning/memory and motor balance. To conclude, the histopathological responses were positively correlated with the degree of damage, as were the long-term behavioral manifestations after controlled cortical impact. All animal procedures were approved by the Institutional Animal Care and Use Committee at Shanghai Jiao Tong University School of Medicine.

Traumatic brain injury in China.

China has more patients with traumatic brain injury (TBI) than most other countries in the world, making this condition a major public health concern. Population-based mortality of TBI in China is estimated to be approximately 13 cases per 100 000 people, which is similar to the rates reported in other countries. The implementation of various measures, such as safety legislation for road traffic, establishment of specialised neurosurgical intensive care units, and the development of evidence-based guidelines, have contributed to advancing prevention and care of patients with TBI in China. However, many challenges remain, which are augmented further by regional differences in TBI care. High-level care, such as intracranial pressure monitoring, is not universally available yet. In the past 30 years, the quality of TBI research in China has substantially improved, as evidenced by an increasing number of clinical trials done. The large number of patients with TBI and specialised trauma centres offer unique opportunities for TBI research in China. Furthermore, the formation and development of research collaborations between China and international groups are considered essential to advancing the quality of TBI care and research in China, and to improve quality of life in patients with this condition.

Inhibition of ferroptosis attenuates tissue damage and improves long-term outcomes after traumatic brain injury in mice.

AIMS: Ferroptosis, a new form of iron-dependent programmed cell death, has been shown to be involved in a range of diseases. However, the role of ferroptosis in traumatic brain injury (TBI) has yet to be elucidated. We aimed to investigate whether ferroptosis is induced after TBI and whether the inhibition of ferroptosis would protect against traumatic brain injury in a controlled cortical impact injury (CCI) mouse model. METHODS: After establishing the TBI model in mice, we determined the biochemical and morphological changes associated with ferroptosis, including iron accumulation with Perl's staining, neuronal cell death with Fluoro-Jade B (FJB) staining, iron metabolism dysfunction with Western blotting, reactive oxygen species (ROS) accumulation with malondialdehyde (MDA) assays, and shrunken mitochondria with transmission electron microscopy. Furthermore, a specific inhibitor of ferroptosis, ferrostatin-1(fer-1), was administrated by cerebral ventricular injection after CCI. We used cresyl violet (CV) staining to assess lesion volume, along with the Morris water maze and beam walk test to evaluate long-term outcomes. RESULTS: TBI was followed by iron accumulation, dysfunctional iron metabolism, the upregulation of ferroptosis-related genes, reduced glutathione peroxidase (GPx) activity, and the accumulation of lipid-reactive oxygen species (ROS). Three days (d) after TBI, transmission electron microscopy (TEM) confirmed that the mitochondria had shrunk a typical characteristic of ferroptosis. Importantly, the administration of Fer-1 by cerebral ventricular injection significantly reduced iron deposition and neuronal degeneration while attenuating injury lesions and improving long-term motor and cognitive function. CONCLUSION: This study demonstrated an effective method with which to treat TBI by targeting ferroptosis.

Effects of Brain Temperature on the Outcome of Patients with Traumatic Brain Injury: A Prospective Observational Study.

A prospective observational study collected temperature data from 51 patients in 11 neurosurgical centers and follow-up outcome information at 6 months in 49 patients. Brain temperature (Tbr) was measured directly by an intraventricular temperature sensor. Axillary temperature (Tax) and rectal temperature (Tre) were measured by electric thermometers. Tbr was 0.4 to 1.5°C higher than body temperature. Tre correlated well with the Tbr (coefficient: 0.7378; p < 0.05). Among all patients, Glasgow Coma Scale (GCS) scores on admission were significantly lower in the patients with post-operatively extreme peak temperature (Tpeak, < 37°C or >39°C in first 24 h) and major temperature variation (Tvari > 1°C in first 12 h; p < 0.05, p < 0.01, respectively). Among the patients with no temperature intervention, the extreme Tpeak group showed a lower Glasgow Outcome Scale-Extended (GOS-E) score at 6 months (p < 0.05) with lower GCS scores on admission (p < 0.01), compared with the moderate Tpeak group. Remarkably, the major Tvari group showed significantly lower GOS-E scores (p < 0.05) with the same GCS scores as the minor Tvari group. Thus, Tre is the better candidate to estimate Tbr. Spontaneously extreme Tpeak in TBI represents both more serious injury on admission and worse prognosis, and Tvari might be used as a novel prognostic parameter in TBI. Brain temperature is therefore one of the critical indicators evaluating injury severity, prognostication, and monitoring in the management of TBI. This prospective observational study has been registered in ClinicalTrials.gov ( https://clinicaltrials.gov ), and the registration number is NCT03068143.

Circular RNA Expression Profiles Alter Significantly after Traumatic Brain Injury in Rats.

Circular RNAs (circRNAs) are involved in a variety of diseases. However, the roles of circRNAs in traumatic brain injury (TBI) remain unknown. In this study, circRNA microarray was used to profile the altered circRNAs in the rat hippocampus following TBI. A total of 192 circRNAs were observed to be differentially expressed (fold change [FC] ≥1.5 and p < 0.05) after TBI, including 98 upregulated and 94 downregulated. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis indicated that many messenger RNAs (mRNAs) transcribed from the host genes of altered circRNAs were implicated in brain damage and neural regeneration. CircRNA/microRNA (miRNA) interaction was predicted using Arraystar's homemade miRNA target prediction software based on TargetScan and miRanda. Thus, our studies have demonstrated altered circRNA expression pattern in the rat hippocampus after TBI, which may play important roles in post-TBI physiological and pathological processes. These findings may provide not only a new direction for studying the molecular mechanisms underlying TBI but also a new possibility for the treatment of TBI by modulating circRNAs.

Electrical Guidance of Human Stem Cells in the Rat Brain.

Limited migration of neural stem cells in adult brain is a roadblock for the use of stem cell therapies to treat brain diseases and injuries. Here, we report a strategy that mobilizes and guides migration of stem cells in the brain in vivo. We developed a safe stimulation paradigm to deliver directional currents in the brain. Tracking cells expressing GFP demonstrated electrical mobilization and guidance of migration of human neural stem cells, even against co-existing intrinsic cues in the rostral migration stream. Transplanted cells were observed at 3 weeks and 4 months after stimulation in areas guided by the stimulation currents, and with indications of differentiation. Electrical stimulation thus may provide a potential approach to facilitate brain stem cell therapies.

Lipoprotein-biomimetic nanostructure enables efficient targeting delivery of siRNA to Ras-activated glioblastoma cells via macropinocytosis.

Hyperactivated Ras regulates many oncogenic pathways in several malignant human cancers including glioblastoma and it is an attractive target for cancer therapies. Ras activation in cancer cells drives protein internalization via macropinocytosis as a key nutrient-gaining process. By utilizing this unique endocytosis pathway, here we create a biologically inspired nanostructure that can induce cancer cells to 'drink drugs' for targeting activating transcription factor-5 (ATF5), an overexpressed anti-apoptotic transcription factor in glioblastoma. Apolipoprotein E3-reconstituted high-density lipoprotein is used to encapsulate the siRNA-loaded calcium phosphate core and facilitate it to penetrate the blood-brain barrier, thus targeting the glioblastoma cells in a macropinocytosis-dependent manner. The nanostructure carrying ATF5 siRNA exerts remarkable RNA-interfering efficiency, increases glioblastoma cell apoptosis and inhibits tumour cell growth both in vitro and in xenograft tumour models. This strategy of targeting the macropinocytosis caused by Ras activation provides a nanoparticle-based approach for precision therapy in glioblastoma and other Ras-activated cancers.

Alteration in Long Non-Coding RNA Expression after Traumatic Brain Injury in Rats.

Traumatic brain injury (TBI) causes a primary insult and initiates a secondary injury cascade. The mechanisms underlying the secondary injury are multifactorial and may include the aberrant expression of long non-coding RNA (lncRNA) post-TBI. Here, lncRNA microarray analysis was performed to profile the altered lncRNAs in the rat hippocampus after TBI. A total of 271 lncRNA probe sets and 1046 messenger RNA (mRNA) probe sets were differentially expressed after TBI. Gene ontology analysis showed that the main components of the most significantly changed categories were inflammation, DNA transcription, apoptosis, and necroptosis. Additionally, the pathway analysis and the pathway relation network revealed correlated pathways mainly involving inflammation, cell cycle, and apoptosis. A co-expression network of these aberrantly expressed lncRNAs and mRNAs was further constructed to predict the potential function of individual lncRNAs. Sub-co-expression networks were formed for the top three lncRNAs: NR_002704, ENSRNOT00000062543, and Zfas1. Thus, our study demonstrated differential expression of a series of lncRNAs in the rat hippocampus after TBI, which may be correlated with post-TBI physiological and pathological processes. The findings also may provide novel targets for further investigation of both the molecular mechanisms underlying TBI and potential therapeutic interventions.

Mild Hypothermia Promotes Pericontusion Neuronal Sprouting via Suppressing Suppressor of Cytokine Signaling 3 Expression after Moderate Traumatic Brain Injury.

Mild therapeutic hypothermia is a candidate for the treatment of traumatic brain injury (TBI). However, the role of mild hypothermia in neuronal sprouting after TBI remains obscure. We used a fluid percussion injury (FPI) model to assess the effect of mild hypothermia on pericontusion neuronal sprouting after TBI in rats. Male Sprague-Dawley rats underwent FPI or sham surgery, followed by mild hypothermia treatment (33°C) or normothermia treatment (37°C) for 3 h. All the rats were euthanized at 7 days after FPI. Neuronal sprouting that was confirmed by an increase in growth associated protein-43 (GAP-43) expression was evaluated using immunofluorescence and Western blot assays. The expression levels of several intrinsic and extrinsic sprouting-associated genes such as neurite outgrowth inhibitor A (NogoA), phosphatase and tensin homolog (PTEN), and suppressor of cytokine signaling 3 (SOCS3) were analyzed by quantitative real-time polymerase chain reaction (RT-PCR). Our results revealed that mild hypothermia significantly increased the expression level of GAP-43 and dramatically suppressed the expression level of interleukin-6 (IL-6) and SOCS3 at 7 days after FPI in the ipsilateral cortex compared with that of the normothermia TBI group. These data suggest that post-traumatic mild hypothermia promotes pericontusion neuronal sprouting after TBI. Moreover, the mechanism of hypothermia-induced neuronal sprouting might be partially associated with decreased levels of SOCS3.

The Role of Posttraumatic Hypothermia in Preventing Dendrite Degeneration and Spine Loss after Severe Traumatic Brain Injury.

Posttraumatic hypothermia prevents cell death and promotes functional outcomes after traumatic brain injury (TBI). However, little is known regarding the effect of hypothermia on dendrite degeneration and spine loss after severe TBI. In the present study, we used thy1-GFP transgenic mice to investigate the effect of hypothermia on the dendrites and spines in layer V/VI of the ipsilateral cortex after severe TBI. We found that hypothermia (33 °C) dramatically prevented dendrite degeneration and spine loss 1 and 7 days after CCI. The Morris water maze test revealed that hypothermia preserved the learning and memory functions of mice after CCI. Hypothermia significantly increased the expression of the synaptic proteins GluR1 and PSD-95 at 1 and 7 days after CCI in the ipsilateral cortex and hippocampus compared with that of the normothermia TBI group. Hypothermia also increased cortical and hippocampal BDNF levels. These results suggest that posttraumatic hypothermia is an effective method to prevent dendrite degeneration and spine loss and preserve learning and memory function after severe TBI. Increasing cortical and hippocampal BDNF levels might be the mechanism through which hypothermia prevents dendrite degeneration and spine loss and preserves learning and memory function.

Global transcriptomic study of atherosclerosis development in rats.

Atherosclerosis is a chronic disease of the arterial wall and a leading cause of death worldwide. Though the pathophysiology of atherosclerotic lesion formation has been studied, we still lack evidence of the global changes in the artery during atherosclerosis. In this report, we induced atherosclerosis in rats and conducted GeneChip analysis on carotid arteries with or without plaque formation. We found that molecular pathways underlying plaque formation in atherosclerosis were related to immune response, angiogenesis, cell proliferation, apoptosis and hypoxic microenvironments, suggesting that the pathophysiology of atherosclerosis is varied. In addition, we showed that three lncRNAs, GAS5, SNHG6 and Zfas1, were significantly increased in the plaque of atherosclerosis patients compared to normal people. A complex interaction of mRNA and lncRNA was identified in atherosclerosis. Our results provide a global transcriptomic network of atherosclerosis development in rats and possible targets that could lead to new clinical applications in the future.

Alteration of microRNA expression in cerebrospinal fluid of unconscious patients after traumatic brain injury and a bioinformatic analysis of related single nucleotide polymorphisms.

PURPOSE: It is becoming increasingly clear that genetic factors play a role in traumatic brain injury (TBI), whether in modifying clinical outcome after TBI or determining susceptibility to it. MicroRNAs are small RNA molecules involved in various pathophysiological processes by repressing target genes at the post- transcriptional level, and TBI alters microRNA expression levels in the hippocampus and cortex. This study was designed to detect differentially expressed microRNAs in the cerebrospinal fluid (CSF) of TBI patients remaining unconscious two weeks after initial injury and to explore related single nucleotide polymorphisms (SNPs). METHODS: We used a microarray platform to detect differential microRNA expression levels in CSF samples from patients with post-traumatic coma compared with samples from controls. A bioinformatic scan was performed covering microRNA gene promoter regions to identify potential functional SNPs. RESULTS: Totally 26 coma patients and 21 controls were included in this study, with similar distribution of age and gender between the two groups. Microarray showed that fourteen microRNAs were differentially expressed, ten at higher and four at lower expression levels in CSF of traumatic coma patients compared with controls (p<0.05). One SNP (rs11851174 allele: C/T) was identified in the motif area of the microRNA hsa-miR-431-3P gene promoter region. CONCLUSION: The altered microRNA expression levels in CSF after brain injury together with SNP identified within the microRNA gene promoter area provide a new perspective on the mechanism of impaired consciousness after TBI. Further studies are needed to explore the association between the specific microRNAs and their related SNPs with post-traumatic unconsciousness.

Improved neurite outgrowth on central nervous system myelin substrate by siRNA-mediated knockdown of Nogo receptor.

PURPOSE: To investigate the in vitro effect of short interfering RNAs (siRNAs) against Nogo receptor (NgR) on neurite outgrowth under an inhibitory substrate of central nervous system (CNS) myelin. METHODS: Three siRNA sequences against NgR were designed and transfected into cerebellar granule cells (CGCs) to screen for the most effcient sequence of NgR siRNA by using reverse transcription polymerase chain reaction (RT-PCR) and immunofluorescence staining. NgR siRNA sequence 1 was found the most efficient which was then transfected into the CGCs grown on CNS myelin substrate to observe its disinhibition for neurite outgrowth. RESULTS: Compared with the scrambled control sequence of siRNA, the NgR siRNA sequence 1 significantly decreased NgR mRNA level at 24 h and 48 h (p <0.05), which was recovered by 96 h after transfection. NgR immunoreactivity was also markedly reduced at 24 and 48 h after the transfection of siRNA sequence 1 compared with that before transfection (p<0.05). The NgR immunoreactivity was recovered after 72 h post-transfection. Moreover, the neurite outgrowth on the myelin substrate was greatly improved within 72 h after the transfection with siRNA sequence 1 compared with the scrambled sequence-transfected group or non-transfected group (p<0.05). CONCLUSION: siRNA-mediated knockdown of NgR expression contributes to neurite outgrowth in vitro.

Expression and mutation of c-Kit in intracranial germ cell tumors: A single-centre retrospective study of 30 cases in China.

Although primary central nervous system (CNS) germ cell tumors (GCTs) are one of the most treatable types of malignant brain tumor, a subset of patients remain resistant to standard chemotherapy. Gain-of-function mutations of the c-Kit gene, and KIT protein expression, have been observed in a number of GCTs, including testicular seminoma, ovarian dysgerminoma and mediastinal seminoma in various ethnic groups. Although a small number of studies have reported the role of c-Kit in CNS GCTs, few have focused on Chinese patients exhibiting CNS GCTs. In the present study, the frequency and location of c-Kit mutations and KIT protein expression levels in CNS GCTs were investigated in 30 patients, between January 1994 and October 2014. Immunohistochemical assays suggested that KIT protein expression was present in 59.1% patients (66.7% in males and 42.9% in females); however, no statistically significant correlation was identified between KIT protein expression and patient clinicopathological features. By performing PCR amplification and direct sequencing, 4 mutational hot spots of the c-Kit gene (exons 9, 11, 13 and 17) were examined, and c-Kit gene mutation was identified in 1/17 (5.9%) CNS germinoma cases. This mutation was located in exon 11 at codon 557-558 WK (Tryptophan-Lysine). No c-Kit gene mutations were detected in non-germinomatous GCTs. Imatinib, a tyrosine kinase inhibitor, may be an effective treatment against standard chemotherapy-resistant CNS germinoma patients exhibiting c-Kit mutations.