Apolipoprotein E4 Polymorphism and Outcomes from Traumatic Brain Injury: A Living Systematic Review and Meta-Analysis.
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ABSTRACT:
SUBMITTER: McFadyen CA
PROVIDER: S-EPMC8054520 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BackgroundTraumatic Brain Injury (TBI) is a major cause of disability and mortality, to which there is currently no comprehensive treatment. Blood Brain Barrier (BBB) dysfunction is well documented in human TBI patients, yet the molecular mechanisms that underlie this neurovascular unit (NVU) pathology remains unclear. The apolipoprotein-E (apoE) protein has been implicated in controlling BBB integrity in an isoform dependent manner, via suppression of Cyclophilin A (CypA)-Matrix metallopeptidase-9 (MMP-9) signaling cascades, however the contribution of this pathway in TBI-induced BBB permeability is not fully investigated.MethodsWe exposed C57Bl/6 mice to controlled cortical impact and assessed NVU and BBB permeability responses up to 21 days post-injury. We pharmacologically probed the role of the CypA-MMP-9 pathway in BBB permeability after TBI using Cyclosporin A (CsA, 20 mg/kg). Finally, as the apoE4 protein is known to be functionally deficient compared to the apoE3 protein, we used humanized APOE mice as a clinically relevant model to study the role of apoE on BBB injury and repair after TBI.ResultsIn C57Bl/6 mice there was an inverse relationship between soluble apoE and BBB permeability, such that damaged BBB stabilizes as apoE levels increase in the days following TBI. TBI mice displayed acute pericyte loss, increased MMP-9 production and activity, and reduced tight-junction expression. Treatment with the CypA antagonist CsA in C57Bl/6 mice attenuates MMP-9 responses and enhances BBB repair after injury, demonstrating that MMP-9 plays an important role in the timing of spontaneous BBB repair after TBI. We also show that apoe mRNA is present in both astrocytes and pericytes after TBI. We report that APOE3 and APOE4 mice have similar acute BBB responses to TBI, but APOE3 mice display faster spontaneous BBB repair than APOE4 mice. Isolated microvessel analysis reveals delayed pericyte repopulation, augmented and sustained MMP-9 expression at the NVU, and impaired stabilization of Zonula Occludens-1, Occludin and Claudin-5 expression at tight junctions in APOE4 mice after TBI compared to APOE3 mice.ConclusionsThese data confirm apoE as an important modulator of spontaneous BBB stabilization following TBI, and highlights the APOE4 allele as a risk factor for poor outcome after TBI.
| S-EPMC5885297 | biostudies-literature
Project description:There is a growing literature on the impact of genetic variation on outcome in traumatic brain injury (TBI). Whereas a substantial proportion of these publications have focused on the apolipoprotein E (APOE) gene, several have explored the influence of other polymorphisms. We undertook a systematic review of the impact of single-nucleotide polymorphisms (SNPs) in non-apolipoprotein E (non-APOE) genes associated with patient outcomes in adult TBI). We searched EMBASE, MEDLINE, CINAHL, and gray literature from inception to the beginning of August 2017 for studies of genetic variance in relation to patient outcomes in adult TBI. Sixty-eight articles were deemed eligible for inclusion into the systematic review. The SNPs described were in the following categories: neurotransmitter (NT) in 23, cytokine in nine, brain-derived neurotrophic factor (BDNF) in 12, mitochondrial genes in three, and miscellaneous SNPs in 21. All studies were based on small patient cohorts and suffered from potential bias. A range of SNPs associated with genes coding for monoamine NTs, BDNF, cytokines, and mitochondrial proteins have been reported to be associated with variation in global, neuropsychiatric, and behavioral outcomes. An analysis of the tissue, cellular, and subcellular location of the genes that harbored the SNPs studied showed that they could be clustered into blood-brain barrier associated, neuroprotective/regulatory, and neuropsychiatric/degenerative groups. Several small studies report that various NT, cytokine, and BDNF-related SNPs are associated with variations in global outcome at 6-12 months post-TBI. The association of these SNPs with neuropsychiatric and behavioral outcomes is less clear. A definitive assessment of role and effect size of genetic variation in these genes on outcome remains uncertain, but could be clarified by an adequately powered genome-wide association study with appropriate recording of outcomes.
| S-EPMC8054522 | biostudies-literature
Project description:In addition to being the greatest genetic risk factor for Alzheimer's disease, expression of the ɛ4 allele of apolipoprotein E can lead to cognitive decline during ageing that is independent of Alzheimer's amyloid-β and tau pathology. In human post-mortem tissue and mouse models humanized for apolipoprotein E, we examined the impact of apolipoprotein E4 expression on brain exosomes, vesicles that are produced within and secreted from late-endocytic multivesicular bodies. Compared to humans or mice homozygous for the risk-neutral ɛ3 allele we show that the ɛ4 allele, whether homozygous or heterozygous with an ɛ3 allele, drives lower exosome levels in the brain extracellular space. In mice, we show that the apolipoprotein E4-driven change in brain exosome levels is age-dependent: while not present at age 6 months, it is detectable at 12 months of age. Expression levels of the exosome pathway regulators tumor susceptibility gene 101 (TSG101) and Ras-related protein Rab35 (RAB35) were found to be reduced in the brain at the protein and mRNA levels, arguing that apolipoprotein E4 genotype leads to a downregulation of exosome biosynthesis and release. Compromised exosome production is likely to have adverse effects, including diminishing a cell's ability to eliminate materials from the endosomal-lysosomal system. This reduction in brain exosome levels in 12-month-old apolipoprotein E4 mice occurs earlier than our previously reported brain endosomal pathway changes, arguing that an apolipoprotein E4-driven failure in exosome production plays a primary role in endosomal and lysosomal deficits that occur in apolipoprotein E4 mouse and human brains. Disruption of these interdependent endosomal-exosomal-lysosomal systems in apolipoprotein E4-expressing individuals may contribute to amyloidogenic amyloid-β precursor protein processing, compromise trophic signalling and synaptic function, and interfere with a neuron's ability to degrade material, all of which are events that lead to neuronal vulnerability and higher risk of Alzheimer's disease development. Together, these data suggest that exosome pathway dysfunction is a previously unappreciated component of the brain pathologies that occur as a result of apolipoprotein E4 expression.
| S-EPMC6308312 | biostudies-literature
Project description:Mild traumatic brain injuries (mTBIs) trigger a neuroinflammatory response, which leads to perturbations in the levels of inflammatory cytokines, resulting in a distinctive profile. A systematic review and meta-analysis were conducted to synthesize data related to levels of inflammatory cytokines in patients with mTBI. The electronic databases EMBASE, MEDLINE, and PUBMED were searched from January 2014 to December 12, 2021. A total of 5,138 articles were screened using a systematic approach based on the PRISMA and R-AMSTAR guidelines. Of these articles, 174 were selected for full-text review and 26 were included in the final analysis. The results of this study demonstrate that within 24 hours, patients with mTBI have significantly higher levels of Interleukin-6 (IL-6), Interleukin-1 Receptor Antagonist (IL-1RA), and Interferon-γ (IFN-γ) in blood, compared to healthy controls in majority of the included studies. Similarly one week following the injury, patients with mTBI have higher circulatory levels of Monocyte Chemoattractant Protein-1/C-C Motif Chemokine Ligand 2 (MCP-1/CCL2), compared to healthy controls in majority of the included studies. The results of the meta-analysis also confirmed these findings by demonstrating significantly elevated blood levels of IL-6, MCP-1/CCL2, and Interleukin-1 beta (IL-1β) in the mTBI population compared to healthy controls (p < 0.0001), particularly in the acute stages (<7 days). Furthermore, it was found that IL-6, Tumor Necrosis Factor-alpha (TNF-α), IL-1RA, IL-10, and MCP-1/CCL2 were associated with poor clinical outcomes following the mTBI. Finally, this research highlights the lack of consensus in the methodology of mTBI studies that measure inflammatory cytokines in the blood, and also provides direction for future mTBI research.
| S-EPMC10213278 | biostudies-literature
Project description:Anticoagulants are commonly prescribed for multiple conditions. However, their influence on traumatic brain injury (TBI) outcomes, especially mortality, is not clear. The present study aimed to explore the effect of prior anticoagulation treatment on the outcomes of TBI. PubMed, Embase, Cochrane Central Register of Controlled Trials, Scopus and CINAHL databases were systematically searched for studies on individuals diagnosed with TBI, with a subgroup on prior anticoagulation therapy. Outcomes of interest included overall mortality, in-hospital mortality, length of hospital and intensive care unit stay, need for neurosurgical intervention and discharge rate. Cohort and case-control studies, published up to September 2023, were examined. Analysis was performed using STATA version 14.2 software and the Newcastle Ottawa Scale was used for bias assessment. A total of 22 studies (102,036 participants) were included in the analysis. Patients with TBI with prior anticoagulation treatment showed a statistically higher overall mortality risk [odds ratio (OR): 1.967, 95% confidence interval (CI): 1.481-2.613]. Subgroup analyses revealed age-specific and TBI severity-specific variations. Prior anticoagulation treatment was associated with a 1.860-times higher rate of in-hospital mortality and a significantly increased likelihood of requiring neurosurgical intervention (OR: 1.351, 95%CI: 1.068-1.708). However, no significant difference was noted in lengths of hospital or ICU stays. Patients with TBI and prior anticoagulation therapy are at higher risk of overall and in-hospital mortality and have significantly higher likelihood of needing neurosurgical interventions. The results emphasized the need for tailored therapeutic approach and more comprehensive clinical guidelines. Future investigations on specific anticoagulant types and immediate post-TBI interventions could offer further insights.
| S-EPMC10928994 | biostudies-literature
Project description:INTRODUCTION:Children who suffer from traumatic brain injury (TBI) are at risk of permanent brain damage and developmental deficits. Reports on neurodevelopmental outcomes in paediatric TBI suffer from small sample size and varying outcome definitions in the neurocognitive domains tested. This protocol describes a systematic review and meta-analysis of paediatric TBI in the following key neurocognitive domains: executive function, perceptual-motor function, language, learning and memory, social cognition and complex attention. METHODS:A comprehensive search comprising studies from Medline, Cochrane, Embase and PsycINFO published from 1988 to 2019 will be conducted. We will include studies on children ?18 years old who suffer from mild, moderate and severe TBI as determined by the Glasgow Coma Scale that report neurocognitive outcomes in domains predetermined by the Diagnostic and Statistical Manual of Mental Disorders fifth edition criteria. Systematic reviews, meta-analyses, randomised controlled trials, case-control, cohort and cross-sectional studies will be included. References from systematic reviews and meta-analyses will be hand-searched for relevant articles. A meta-analysis will be performed and effect sizes will be calculated to summarise the magnitude of change in each neurocognitive domain compared at different timepoints and stratified by severity of TBI. Included studies will be pooled using pooled standardised mean differences with a random effects model to determine an overall effect. In the scenario that we are unable to pool the studies, we will perform a narrative analysis. ETHICS AND DISSEMINATION:Ethics approval is not required for this study.The authors of this study will publish and present the findings in a peer-reviewed journal as well as national and international conferences. The results of this study will provide understanding into the association between different severities of paediatric TBI and long-term neurocognitive outcomes. PROSPERO REGISTRATION NUMBER:CRD42020152680.
| S-EPMC7304810 | biostudies-literature
Project description:Guidelines aim to improve the quality of medical care and reduce treatment variation. The extent to which guidelines are adhered to in the field of traumatic brain injury (TBI) is unknown. The objectives of this systematic review were to (1) quantify adherence to guidelines in adult patients with TBI, (2) examine factors influencing adherence, and (3) study associations of adherence to clinical guidelines and outcome. We searched EMBASE, MEDLINE, Cochrane Central, PubMed, Web of Science, PsycINFO, SCOPUS, CINAHL, and grey literature in October 2014. We included studies of evidence-based (inter)national guidelines that examined the acute treatment of adult patients with TBI. Methodological quality was assessed using the Research Triangle Institute item bank and Quality in Prognostic Studies Risk of Bias Assessment Instrument. Twenty-two retrospective and prospective observational cohort studies, reported in 25 publications, were included, describing adherence to 13 guideline recommendations. Guideline adherence varied considerably between studies (range 18-100%) and was higher in guideline recommendations based on strong evidence compared with those based on lower evidence, and lower in recommendations of relatively more invasive procedures such as craniotomy. A number of patient-related factors, including age, Glasgow Coma Scale, and intracranial pathology, were associated with greater guideline adherence. Guideline adherence to Brain Trauma Foundation guidelines seemed to be associated with lower mortality. Guideline adherence in TBI is suboptimal, and wide variation exists between studies. Guideline adherence may be improved through the development of strong evidence for guidelines. Further research specifying hospital and management characteristics that explain variation in guideline adherence is warranted.
| S-EPMC8054518 | biostudies-literature
Project description:The antifibrinolytic agent tranexamic acid (TXA) has demonstrated clinical benefit in trauma patients with severe bleeding, but its effectiveness in patients with traumatic brain injury (TBI) is unclear. We conducted a systematic review to evaluate the following research question: In ED patients with or at risk of intracranial hemorrhage (ICH) secondary to TBI, does TXA compared to placebo improve patients' outcomes?MEDLINE, EMBASE, CINAHL, and other databases were searched for randomized controlled trial (RCT) or quasi-RCT studies that compared the effect of TXA to placebo on outcomes of TBI patients. The main outcomes of interest included mortality, neurologic function, hematoma expansion, and adverse effects. We used "Grading quality of evidence and strength of recommendations" to assess the quality of trials. Two authors independently abstracted data using a data collection form. Results from studies were pooled when appropriate.Of 1030 references identified through the search, 2 high-quality RCTs met inclusion criteria. The effect of TXA on mortality had a pooled relative risk of 0.64 (95% confidence interval [CI], 0.41-1.02); on unfavorable functional status, a relative risk of 0.77 (95% CI, 0.59-1.02); and on ICH progression, a relative risk of 0.76 (95% CI, 0.58-0.98). No serious adverse effects (such as thromboembolic events) associated with TXA group were reported in the included trials.Pooled results from the 2 RCTs demonstrated statistically significant reduction in ICH progression with TXA and a nonstatistically significant improvement of clinical outcomes in ED patients with TBI. Further evidence is required to support its routine use in patients with TBI.
| S-EPMC4988127 | biostudies-literature
Project description:BackgroundTraumatic brain injury (TBI) causes mortality and long-term disability among young adults and imposes a notable cost on the healthcare system. In addition to the first physical hit, secondary injury, which is associated with increased intracranial pressure (ICP), is defined as biochemical, cellular, and physiological changes after the physical injury. Mannitol and Hypertonic saline (HTS) are the treatment bases for elevated ICP in TBI. This systematic review and meta-analysis evaluates the effectiveness of HTS in the management of patients with TBI.MethodsThis study was conducted following the Joanna Briggs Institute (JBI) methods and PRISMA statement. A systematic search was performed through six databases in February 2022, to find studies that evaluated the effects of HTS, on increased ICP. Meta-analysis was performed using comprehensive meta-analysis (CMA).ResultsOut of 1321 results, 8 studies were included in the systematic review, and 3 of them were included in the quantitative synthesis. The results of the meta-analysis reached a 35.9% (95% CI 15.0-56.9) reduction in ICP in TBI patients receiving HTS, with no significant risk of publication bias (t-value = 0.38, df = 2, p-value = 0.73). The most common source of bias in our included studies was the transparency of blinding methods for both patients and outcome assessors.ConclusionHTS can significantly reduce the ICP, which may prevent secondary injury. Also, based on the available evidence, HTS has relatively similar efficacy to Mannitol, which is considered the gold standard therapy for TBI, in boosting patients' neurological condition and reducing mortality rates.
| S-EPMC9677698 | biostudies-literature
Project description:To examine whether apolipoprotein e4 (APOE) status moderates the association of family environment with child functioning following early traumatic brain injury (TBI).Sixty-five children with moderate to severe TBI and 70 children with orthopedic injury (OI) completed assessments 6, 12, 18 months, and 3.5 and 6.8 years post injury. DNA was extracted from saliva samples and genotyped for APOE e4 status. Linear mixed models examined moderating effects of APOE e4 status on associations between two family environment factors (parenting style, home environment) and three child outcomes (executive functioning, behavioral adjustment, adaptive functioning).Children with TBI who were carriers of the e4 allele showed poorer adaptive functioning relative to non-carriers with TBI and children with OI in the context of low authoritarianism. At high levels of authoritarianism, non-carriers with TBI showed the poorest adaptive functioning among groups. There were no main effects or interactions involving APOE and executive functioning or behavioral adjustment.The APOE e4 allele was detrimental for long-term adaptive functioning in the context of positive parenting, whereas in less optimal parenting contexts, being a non-carrier was detrimental. We provide preliminary evidence for an interaction of APOE e4 status and parenting style in predicting long-term outcomes following early TBI. (JINS, 2016, 22, 859-864).
| S-EPMC5476473 | biostudies-literature