Coagulation Abnormalities Associated with Severe Isolated Traumatic Brain Injury: Cerebral Arterio-Venous Differences in Coagulation and Inflammatory Markers

Distinctive patterns of sequential platelet counts following blunt traumatic brain injury predict outcomes

OBJECTIVE

To determine the role of platelet counts in the context of the decision to treat patients with non-compounded, non-surgically-treated blunt traumatic brain injury (NCNS-bTBI) with anticoagulants/antiaggregants.

METHODS

A retrospective analysis of 141 anticoagulants/antiaggregants-naïve patients with NCNS-bTBI. Changes in PT-INR and prolonged aPTT were examined and correlated with Marshall and Rotterdam scores, clinical and neuroradiological outcomes.

RESULTS

Three groups of platelet counts were identified. Group 1 (83% of patients) had normal platelet counts (150,000-450,000 platelets/mm3) from admission to discharge. Group 2 (13%) developed transient thrombocytopenia (<150,000 platelets/mm3) 2-3 days post-trauma. Group 3 (4%) developed extreme thrombocytosis > 1,000,000/mm3 platelets 6-9 days post-trauma. Neither acute coagulopathy of trauma nor progressive hemorrhagic insults followed NCNS-bTBI. Moreover, while patients with thrombocytosis/extreme thrombocytosis presented with a worse Glasgow coma score (GCS) on admission (8.8 ± 2.9 vs. 13 ± 2, p < 0.01) and had longer hospitalization (13.5 ± 10.4 vs. 4.5 ± 2.1 days), their improvement at discharge was the highest (delta GCS, 4 ± 2.8 vs. 1.2 ± 2.1, p = 0.05). Traumatic subarachnoid hemorrhage was associated with isolated thrombocytosis and 'best improvement.' No thromboembolic or hemorrhagic complications occurred.

CONCLUSION

NCNS-bTBI, thrombocytosis was correlated with better outcomes and was not associated with an increased risk for developing thromboembolism or hemorrhage, precluding the immediate need for any additional antiaggregates.

Long Non-Coding RNA Analysis: Severe Pathogenicity in Chicken Embryonic Visceral Tissues Infected with Highly Virulent Newcastle Disease Virus-A Comparison to the Avirulent Vaccine Virus

There are significant variations in pathogenicity among different virulent strains of the Newcastle disease virus (NDV). Virulent NDV typically induces severe pathological changes and high mortality rates in infected birds, while avirulent NDV usually results in asymptomatic infection. Currently, the understanding of the specific mechanisms underlying the differences in host pathological responses and symptoms caused by various virulent NDV strains remains limited. Long non-coding RNA (lncRNA) can participate in a range of biological processes and plays a crucial role in viral infection and replication. Therefore, this study employed RNA-Seq to investigate the transcriptional profiles of chicken embryos' visceral tissues (CEVTs) infected with either the virulent NA-1 strain or avirulent LaSota strain at 24 hpi and 36 hpi. Using bioinformatic methods, we obtained a total of 2532 lncRNAs, of which there were 52 and 85 differentially expressed lncRNAs at 24 hpi and 36 hpi, respectively. LncRNA analysis revealed that the severe pathological changes and symptoms induced by virulent NDV infection may be partially attributed to related target genes, regulated by differentially expressed lncRNAs such as MSTRG.1545.5, MSTRG.14601.6, MSTRG.7150.1, and MSTRG.4481.1. Taken together, these findings suggest that virulent NDV infection exploits the host's metabolic resources and exerts an influence on the host's metabolic processes, accompanied by excessive activation of the immune response. This impacts the growth and development of each system of CEVTs, breaches the blood-brain barrier, inflicts severe damage on the nervous system, and induces significant lesions. These observations may be attributed to variations in pathology. Consequently, novel insights were obtained into the intricate regulatory mechanisms governing NDV and host interactions. This will aid in unraveling the molecular mechanisms underlying both virulent and avirulent forms of NDV infection.

Risk factors for thromboembolic complications in isolated severe head injury

PURPOSE

Patients with traumatic brain injury (TBI) are at high risk for venous thromboembolism (VTE). The aim of the present study is to identify factors independently associated with VTE events. Specifically, we hypothesized that the mechanism of penetrating head trauma might be an independent factor associated with increased VTE events when compared with blunt head trauma.

METHODS

The ACS-TQIP database (2013-2019) was queried for all patients with isolated severe head injuries (AIS 3-5) who received VTE prophylaxis with either unfractionated heparin or low-molecular-weight heparin. Transfers, patients who died within 72 h and those with a hospital length of stay < 48 h were excluded. Multivariable analysis was used as the primary analysis to identify independent risk factors for VTE in isolated severe TBI.

RESULTS

A total of 75,570 patients were included in the study, 71,593 (94.7%) with blunt and 3977 (5.3%) with penetrating isolated TBI. Penetrating trauma mechanism (OR 1.49, CI 95% 1.26-1.77), increasing age (age 16-45: reference; age > 45-65: OR 1.65, CI 95% 1.48-1.85; age > 65-75: OR 1.71, CI 95% 1.45-2.02; age > 75: OR 1.73, CI 95% 1.44-2.07), male gender (OR 1.53, CI 95% 1.36-1.72), obesity (OR 1.35, CI 95% 1.22-1.51), tachycardia (OR 1.31, CI 95% 1.13-1.51), increasing head AIS (AIS 3: reference; AIS 4: OR 1.52, CI 95% 1.35-1.72; AIS 5: OR 1.76, CI 95% 1.54-2.01), associated moderate injuries (AIS = 2) of the abdomen (OR 1.31, CI 95% 1.04-1.66), spine (OR 1.35, CI 95% 1.19-1.53), upper extremity (OR 1.16, CI 95% 1.02-1.31), lower extremity (OR 1.46, CI 95% 1.26-1.68), craniectomy/craniotomy or ICP monitoring (OR 2.96, CI 95% 2.65-3.31) and pre-existing hypertension (OR 1.18, CI 95% 1.05-1.32) were identified as independent risk factors for VTE complications in isolated severe head injury. Increasing GCS (OR 0.93, CI 95% 0.92-0.94), early VTE prophylaxis (OR 0.48, CI 95% 0.39-0.60) and LMWH compared to heparin (OR 0.74, CI 95% 0.68-0.82) were identified as protective factors for VTE complications.

CONCLUSION

The identified factors independently associated with VTE events in isolated severe TBI need to be considered in VTE prevention measures. In penetrating TBI, an even more aggressive VTE prophylaxis management may be justified as compared to that in blunt.

The proteomic and metabolomic signatures of isolated and polytrauma traumatic brain injury

BACKGROUND

The interactions of polytrauma, shock, and traumatic brain injury (TBI) on thromboinflammatory responses remain unclear and warrant investigation as we strive towards personalized medicine in trauma. We hypothesized that comprehensive omics characterization of plasma would identify unique metabolic and thromboinflammatory pathways following TBI.

METHODS

Patients were categorized as TBI vs Non-TBI, and stratified into Polytrauma or minimally injured. Discovery 'omics was employed to quantify the top differently expressed proteins and metabolites of TBI and Non-TBI patient groups.

RESULTS

TBI compared to Non-TBI showed gene enrichment in coagulation/complement cascades and neuronal markers. TBI was associated with elevation in glycolytic metabolites and conjugated bile acids. Division into isolated TBI vs polytrauma showed further distinction of proteomic and metabolomic signatures.

CONCLUSION

Identified mediators involving in neural inflammation, blood brain barrier disruption, and bile acid building leading to TBI associated coagulopathy offer suggestions for follow up mechanistic studies to target personalized interventions.

Tackling Neuroinflammation After Traumatic Brain Injury: Complement Inhibition as a Therapy for Secondary Injury

Traumatic brain injury (TBI) is a leading cause of mortality, sensorimotor morbidity, and neurocognitive disability. Neuroinflammation is one of the key drivers causing secondary brain injury after TBI. Therefore, attenuation of the inflammatory response is a potential therapeutic goal. This review summarizes the most important neuroinflammatory pathophysiology resulting from TBI and the clinical trials performed to attenuate neuroinflammation. Studies show that non-selective attenuation of the inflammatory response, in the early phase after TBI, might be detrimental and that there is a gap in the literature regarding pharmacological trials targeting specific pathways. The complement system and its crosstalk with the coagulation system play an important role in the pathophysiology of secondary brain injury after TBI. Therefore, regaining control over the complement cascades by inhibiting overshooting activation might constitute useful therapy. Activation of the complement cascade is an early component of neuroinflammation, making it a potential target to mitigate neuroinflammation in TBI. Therefore, we have described pathophysiological aspects of complement inhibition and summarized animal studies targeting the complement system in TBI. We also present the first clinical trial aimed at inhibition of complement activation in the early days after brain injury to reduce the risk of morbidity and mortality following severe TBI.

Detecting traumatic brain injury-induced coagulopathy: What we are testing and what we are not

ABSTRACT

Coagulopathy after traumatic brain injury (TBI) is common and has been closely associated with poor clinical outcomes for the affected patients. Traumatic brain injury-induced coagulopathy (TBI-IC) is consumptive in nature and evolves rapidly from an injury-induced hypercoagulable state. Traumatic brain injury-induced coagulopathy defined by laboratory tests is significantly more frequent than clinical coagulopathy, which often manifests as secondary, recurrent, or delayed intracranial or intracerebral hemorrhage. This disparity between laboratory and clinical coagulopathies has hindered progress in understanding the pathogenesis of TBI-IC and developing more accurate and predictive tests for this severe TBI complication. In this review, we discuss laboratory tests used in clinical and research studies to define TBI-IC, with specific emphasis on what the tests detect and what they do not. We also offer perspective on developing more accurate and predictive tests for this severe TBI complication.

Perfluorocarbons cause thrombocytopenia, changes in RBC morphology and death in a baboon model of systemic inflammation

A perfluorocarbon (PFC) investigated for treatment of traumatic brain injury (TBI) delivers oxygen to support brain function, but causes transient thrombocytopenia. TBI can cause acute inflammation with resulting thrombocytopenia; an interaction between the PFC effects and TBI inflammation might exacerbate thrombocytopenia. Therefore, PFC effects on platelet (PLT) function and hemostasis in a lipopolysaccharide (LPS) model of inflammation in the baboon were studied. Animals were randomized to receive saline ±LPS, and ± one of two doses of PFC. PLT count, transmission electron microscopy, and microparticle populations were quantified at baseline (BL) and at 2, 24, 48, 72, and 96 hours; hemostatic parameters for aggregometry and for blood clotting were measured at baseline (BL) and days 3 and 4. Injection of vehicle and LPS caused thrombocytopenia within hours; PFCs caused delayed thrombocytopenia beginning 48 hours post-infusion. LPS+PFC produced a more prolonged PLT decline and decreased clot strength. LPS+PFC increased ADP-stimulated aggregation, but PFC alone did not. Microparticle abundance was greatest in the LPS+PFC groups. LPS+PFC caused diffuse microvascular hemorrhage and death in 2 of 5 baboons in the low dose LPS-PFC group and 2 of 2 in the high dose LPS-PFC group. Necropsy and histology suggested death was caused by shock associated with hemorrhage in multiple organs. Abnormal morphology of platelets and red blood cells were notable for PFC inclusions. In summary, PFC infusion caused clinically significant thrombocytopenia and exacerbated LPS-induced platelet activation. The interaction between these effects resulted in decreased hemostatic capacity, diffuse bleeding, shock and death.

Epidemiology and clinical characteristics of posttraumatic hospitalized patients with symptoms related to venous thromboembolism: a single-center retrospective study

Purpose: The aim of this study was to investigate the epidemiology of trauma inpatients with venous thromboembolism (VTE) symptoms diagnosed using computed tomographic angiography (CTA) in KoreaMethods: In total, 7,634 patients admitted to the emergency department of Gachon University Gil Medical Center, a tertiary hospital, and hospitalized between July 1, 2018 and December 31, 2020 were registered for this study. Of these patients, 278 patients who underwent CTA were enrolled in our study. Results: VTE was found in 120 of the 7,634 patients (1.57%), and the positive diagnosis rate of the 278 patients who underwent CTA was 43.2% (120 of 278). The incidence of VTE was statistically significantly higher among those with severe head and neck injuries (Abbreviated Injury Scale, 3–5) than among those with nonsevere head and neck injuries (Abbreviated Injury Scale, 0–2; P=0.038). In a subgroup analysis, the severe and nonsevere head and neck injury groups showed statistically significant differences in known independent risk factors for VTE. In logistic regression analysis, the adjusted odds ratio of severe head and neck injury (Abbreviated Injury Scale, 3–5) for VTE was 1.891 (95% confidence interval, 1.043–3.430). Conclusions: Trauma patients with severe head and neck injuries are more susceptible to VTE than those with nonsevere head and neck injuries. Thus, physicians must consider CTA as a priority for the diagnosis of VTE in trauma patients with severe head and neck injuries who show VTE-associated symptoms.

Neutrophil to lymphocyte ratio in the prediction of coagulopathy in traumatic brain injury

Aim: Traumatic brain injury (TBI) is a public health issue of increasing incidence. Coagulopathy after TBI is a frequent event, associated with a poor prognosis, and biomarkers that could predict coagulopathy occurrence are needed. The neutrophil-to-lymphocyte ratio (NLR) is useful as a cost-effective biomarker to assess prognosis and the need for cranial computed tomography in patients with mild TBI. As no study has yet evaluated the association of NLR with coagulopathy, we investigated whether the NLR at presentation could predict coagulopathy occurrence after TBI. Materials & methods: A retrospective study was conducted of patients aged >18 years who attended the emergency department (ED) with TBI, over a 3-year period. We included all patients for whom the NLR at presentation was available, and who underwent a brain CT scan. Results: The study included 173 patients (mean age 57.4 ± 21.1 years) with TBI, the most frequent cause of which was a fall. According to the Glasgow Coma Scale, 37 patients had severe TBI, 19 moderate and 117 mild TBI and 40 patients (23.1%) developed coagulopathy. Their mean NLR was 7.5 ± 6.7. Using receiver operating characteristic curve analysis, a cut-off value of 4.2 for NLR had 87.5% sensitivity and 52.9% specificity for predicting coagulopathy occurrence. Conclusion: Coagulopathy occurs frequently after TBI. This study investigated the value of NLR as a biomarker to predict coagulopathy occurrence, and concluded that NLR might be a novel and inexpensive biomarker for decision making in the management of TBI. Combination of NLR with other low-cost biomarkers and the clinical findings might further increase accuracy in the prediction of coagulopathy.

Viscoelastic Testing in Traumatic Brain Injury: Key Research Insights

The role of viscoelastic testing in the evaluation and management of traumatic brain injury (TBI) remains a subject of ongoing exploration. This review highlights four key publications that provide significant insights into this subject. Holcomb et al. provided early evidence of the relationship between thromboelastography (TEG) and conventional coagulation tests (CCTs). Later, Samuels et al. used TEG to identify a unique coagulopathy phenotype in TBI characterized by a notable absence of fibrinolytic abnormalities. Dixon et al. built upon these findings by exploring the application of TEG in the context of antifibrinolytic administration, noting a similar lack of effect on LY30. Finally, Guillotte et al. demonstrated the utility of TEG-PM in assessing platelet dysfunction in TBI. While these studies provide key early support for the utility of viscoelastic testing in the TBI, further exploration is needed to define evidence-based guidelines for clinical application.

Prospective Analysis of Coagulopathy Associated with Isolated Traumatic Brain Injury and Clinical Outcome

Introduction Traumatic brain injury (TBI) affects the coagulation pathway in a distinct way than does extracranial trauma. The extent of coagulation abnormalities varies from bleeding diathesis to disseminated thrombosis.

Design Prospective study.

Methods The study included 50 patients of isolated TBI with cohorts of moderate (MHI) and severe head injury (SHI). Coagulopathy was graded according to the values of parameters in single laboratory. The incidence of coagulopathy according to the severity of TBI and correlation with disseminated intravascular coagulation (DIC) score, platelets, prothrombin time (PT), activated partial thromboplastin time (APTT), D-dimer, and fibrinogen was observed. The comparison was also made between expired and discharged patients within each group. It also compared coagulation derailments with clinical presentation (Glasgow Coma Scale [GCS]) and outcome (Glasgow Outcome Scale [GOS]).

Results Road traffic accident was the primary (72%) mode of injury. Fifty-two percent had MHI and rest had SHI. Eighty-four percent of cases were managed conservatively. The mean GCS was 12.23 and 5.75 in MHI and SHI, respectively. Sixty-two percent of MHI and 96% of the patients with SHI had coagulation abnormalities. On statistical analysis, DIC score (p < 0.001) strongly correlated with the severity of head injury and GOS. PT and APTT were also significantly associated with the severity of TBI. In patients with moderate TBI, D-dimer and platelet counts showed association with clinical outcome. Fibrinogen levels did not show any statistical significance. The mean platelet counts remained normal in both the groups of TBI. The mean GOS was 1.54 and 4.62 in SHI and MHI, respectively.

Conclusion Coagulopathy is common in isolated TBI. The basic laboratory parameters are reliable predictors of coagulation abnormalities in TBI. Coagulopathy is directly associated with the severity of TBI, GCS, and poor outcome.

Fibrinolysis in Traumatic Brain Injury: Diagnosis, Management, and Clinical Considerations

Posttraumatic coagulopathy involves disruption of both the coagulation and fibrinolytic pathways secondary to tissue damage, hypotension, and inflammatory upregulation. This phenomenon contributes to delayed complications after traumatic brain injury (TBI), including intracranial hemorrhage progression and systemic disseminated intravascular coagulopathy. Development of an early hyperfibrinolytic state may result in uncontrolled bleeding and is associated with increased mortality in patients with TBI. Although fibrinolytic assays are not routinely performed in the assessment of posttraumatic coagulopathy, circulating biomarkers such as D-dimer and fibrin degradation products have demonstrated potential utility in outcome prediction. Unfortunately, the relatively delayed nature of these tests limits their clinical utility. In contrast, viscoelastic tests are able to provide a rapid global assessment of coagulopathy, although their ability to reliably identify disruptions in the fibrinolytic cascade remains unclear. Limited evidence supports the use of hypertonic saline, cryoprecipitate, and plasma to correct fibrinolytic disruption; however, some studies suggest more harm than benefit. Recently, early use of tranexamic acid in patients with TBI and confirmed hyperfibrinolysis has been proposed as a strategy to further improve clinical outcomes. Moving forward, further delineation of TBI phenotypes and the clinical implications of fibrinolysis based on phenotypic variation is needed. In this review, we summarize the clinical aspects of fibrinolysis in TBI, including diagnosis, treatment, and clinical correlates, with identification of targeted areas for future research efforts.

Fibrinolytic Activation in Patients with Progressive Intracranial Hemorrhage after Traumatic Brain Injury

Progression of intracranial hemorrhage (PICH) is a significant cause of secondary brain injury in patients with traumatic brain injury (TBI). Previous studies have implicated a variety of mediators that contribute to PICH. We hypothesized that patients with PICH would display either a hypocoagulable state, hyperfibrinolysis, or both. We conducted a prospective study of adult trauma patients with isolated TBI. Blood was obtained for routine coagulation assays, platelet count, fibrinogen, thrombelastography, markers of thrombin generation, and markers of fibrinolysis at admission and 6, 12, 24, and 48 h. Univariate analyses were performed to compare baseline characteristics between groups. Linear regression models were created, adjusting for baseline differences, to determine the relationship between individual assays and PICH. One hundred forty-one patients met entry criteria, of whom 71 had hemorrhage progression. Patients with PICH had a higher Injury Severity Score and Abbreviated Injury Scale score (head), a lower Glasgow Coma Scale score, and lower plasma sodium on admission. Patients with PICH had higher D-dimers on admission. After adjusting for baseline differences, elevated D-dimers remained significantly associated with PICH compared to patients without PICH at admission. Hypocoagulation was not significantly associated with PICH in these patients. The association between PICH and elevated D-dimers early after injury suggests that fibrinolytic activation may contribute to PICH in patients with TBI.

Time Course of Hemostatic Disruptions After Traumatic Brain Injury: A Systematic Review of the Literature

Almost two-thirds of patients with severe traumatic brain injury (TBI) develop some form of hemostatic disturbance, which contributes to poor outcome. While the initial head injury often leads to impaired clot formation, TBI is also associated with an increased risk of thrombosis. Most likely there is a progression from early bleeding to a later prothrombotic state. In this paper, we systematically review the literature on the time course of hemostatic disruptions following TBI. A MEDLINE search was performed for TBI studies reporting the trajectory of hemostatic assays over time. The search yielded 5,049 articles, of which 4,910 were excluded following duplicate removal as well as title and abstract review. Full-text assessment of the remaining articles yielded 33 studies that were included in the final review. We found that the first hours after TBI are characterized by coagulation cascade dysfunction and hyperfibrinolysis, both of which likely contribute to lesion progression. This is then followed by platelet dysfunction and decreased platelet count, the clinical implication of which remains unclear. Later, a poorly defined prothrombotic state emerges, partly due to fibrinolysis shutdown and hyperactive platelets. In the clinical setting, early administration of the antifibrinolytic agent tranexamic acid has proved effective in reducing head-injury-related mortality in a subgroup of TBI patients. Further studies evaluating the time course of hemostatic disruptions after TBI are warranted in order to identify windows of opportunity for potential treatment options.

Does Complement-Mediated Hemostatic Disturbance Occur in Traumatic Brain Injury? A Literature Review and Observational Study Protocol

Despite improvements in medical triage and tertiary care, traumatic brain injury (TBI) remains associated with significant morbidity and mortality. Almost two-thirds of patients with severe TBI develop some form of hemostatic disturbance, which contributes to poor outcome. In addition, the complement system, which is abundant in the healthy brain, undergoes significant intra- and extracranial amplification following TBI. Previously considered to be structurally similar but separate systems, evidence of an interaction between the complement and coagulation systems in non-TBI cohorts has accumulated, with the activation of one system amplifying the activation of the other, independent of their established pathways. However, it is not known whether this interaction exists in TBI. In this review we summarize the available literature on complement activation following TBI, and the crosstalk between the complement and coagulation systems. We demonstrate how the complement system interacts with the coagulation cascade by activating the intrinsic coagulation pathway and by bypassing the initial cascade and directly producing thrombin as well. This crosstalk also effects platelets, where evidence points to a relationship with the complement system on multiple levels, with complement anaphylatoxins being able to induce disproportionate platelet activation and adhesion. The complement system also stimulates thrombosis by inhibiting fibrinolysis and stimulating endothelial cells to release prothrombotic microparticles. These interactions see clinical relevance in several disorders where a deficiency in complement regulation seems to result in a prothrombotic clinical presentation. Finally, based on these observations, we present the outline of an observational cohort study that is currently under preparation and aimed at assessing how complement influences coagulation in patients with isolated TBI.

Catastrophic Non-Survivable Brain Injury Care-Role 2/3

A catastrophic brain injury is defined as any brain injury that is expected to result in permanent loss of all brain function above the brain stem level. These clinical recommendations will help stabilize the patient so that they may be safely evacuated from theater. In addition to cardiovascular and hemodynamic goals, special attention must be paid to their endocrine dysfunction and its treatment-specifically steroid, insulin and thyroxin (t4) replacement while evaluating for and treating diabetes insipidus. Determining the futility of care coupled with resource management must also be made at each echelon. Logistical coordination and communication is paramount to expedite these patients to higher levels of care so that there is an increased probability of reuniting them with their family.

Sympathoadrenal Activation is Associated with Acute Traumatic Coagulopathy and Endotheliopathy in Isolated Brain Injury

Background:

Acute coagulopathy after traumatic brain injury (TBI) involves a complex multifactorial hemostatic response that is poorly characterized. Objectives: To examine early posttraumatic alterations in coagulofibrinolytic, endothelial, and inflammatory blood biomarkers in relation to sympathetic nervous system (SNS) activation and 6-month patient outcomes, using multivariate partial least-squares (PLS) analysis.

Patients and Methods:

A multicenter observational study of 159 adult isolated TBI patients admitted to the emergency department at an urban level I trauma center, was performed. Plasma concentrations of 6 coagulofibrinolytic, 10 vascular endothelial, 19 inflammatory, and 2 catecholamine biomarkers were measured by immunoassay on admission and 24 h postinjury. Neurological outcome at 6 months was assessed using the Extended Glasgow Outcome Scale. PLS-discriminant analysis was used to identify salient biomarker contributions to unfavorable outcome, whereas PLS regression analysis was used to evaluate the covariance between SNS correlates (catecholamines) and biomarkers of coagulopathy, endotheliopathy, and inflammation.

Results:

Biomarker profiles in patients with an unfavorable outcome displayed procoagulation, hyperfibrinolysis, glycocalyx and endothelial damage, vasculature activation, and inflammation. A strong covariant relationship was evident between catecholamines and biomarkers of coagulopathy, endotheliopathy, and inflammation at both admission and 24 h postinjury.

Conclusions:

Biomarkers of coagulopathy and endotheliopathy are associated with poor outcome after TBI. Catecholamine levels were highly correlated with endotheliopathy and coagulopathy markers within the first 24 h after injury. Further research is warranted to characterize the pathogenic role of SNS-mediated hemostatic alterations in isolated TBI.

Thromboelastography After Murine TBI and Implications of Beta-Adrenergic Receptor Knockout

BACKGROUND

The source of coagulopathy in traumatic brain injury (TBI) is multifactorial and may include adrenergic stimulation. The aim of this study was to assess coagulopathy after TBI using thromboelastography (TEG), and to investigate the implications of β-adrenergic receptor knockout.

METHODS

Adult male wild type c57/bl6 (WT) and β1/β2-adrenergic receptor knockout (BKO) mice were assigned to either TBI (WT-TBI, BKO-TBI) or sham injury (WT-sham, BKO-sham). Mice assigned to TBI were subject to controlled cortical impact (CCI). At 24 h post-injury, whole blood samples were obtained and taken immediately for TEG.

RESULTS

At 24 h after injury, a trend toward increased fibrinolysis was seen in WT-TBI compared to WT-sham although this did not reach significance (EPL 8.1 vs. 0 %, p = 0.18). No differences were noted in fibrinolysis in BKO-TBI compared to BKO-sham (LY30 2.6 vs. 2.5 %, p = 0.61; EPL 3.4 vs. 2.9 %, p = 0.61). In addition BKO-TBI demonstrated increased clot strength compared to BKO-sham (MA 76.6 vs. 68.6, p = 0.03; G 18.2 vs. 11.3, p = 0.03).

CONCLUSIONS

In a mouse TBI model, WT mice sustaining TBI demonstrated a trend toward increased fibrinolysis at 24 h after injury while BKO mice did not. These findings suggest β-blockade may attenuate the coagulopathy of TBI and minimize progression of intracranial hemorrhage by reducing fibrinolysis and increasing clot strength.

Neurologic complications of polytrauma

Neurologic complications in polytrauma can be classified by etiology and clinical manifestations: neurovascular, delirium, and spinal or neuromuscular problems. Neurovascular complications include ischemic strokes, intracranial hemorrhage, or the development of traumatic arteriovenous fistulae. Delirium and encephalopathy have a reported incidence of 67-92% in mechanically ventilated polytrauma patients. Causes include sedation, analgesia/pain, medications, sleep deprivation, postoperative state, toxic ingestions, withdrawal syndromes, organ system dysfunction, electrolyte/metabolic abnormalities, and infections. Rapid identification and treatment of the underlying cause are imperative. Benzodiazepines increase the risk of delirium, and alternative agents are preferred sedatives. Pharmacologic treatment of agitated delirium can be achieved with antipsychotics. Nonconvulsive seizures and status epilepticus are not uncommon in surgical/trauma intensive care unit (ICU) patients, require electroencephalography for diagnosis, and need timely management. Spinal cord ischemia is a known complication in patients with traumatic aortic dissections or blunt aortic injury requiring surgery. Thoracic endovascular aortic repair has reduced the paralysis rate. Neuromuscular complications include nerve and plexus injuries, and ICU-acquired weakness. In polytrauma, the neurologic examination is often confounded by pain, sedation, mechanical ventilation, and distracting injuries. Regular sedation pauses for examination and maintaining a high index of suspicion for neurologic complications are warranted, particularly because early diagnosis and management can improve outcomes.

Chronic Histopathological and Behavioral Outcomes of Experimental Traumatic Brain Injury in Adult Male Animals

The purpose of this review is to survey the use of experimental animal models for studying the chronic histopathological and behavioral consequences of traumatic brain injury (TBI). The strategies employed to study the long-term consequences of TBI are described, along with a summary of the evidence available to date from common experimental TBI models: fluid percussion injury; controlled cortical impact; blast TBI; and closed-head injury. For each model, evidence is organized according to outcome. Histopathological outcomes included are gross changes in morphology/histology, ventricular enlargement, gray/white matter shrinkage, axonal injury, cerebrovascular histopathology, inflammation, and neurogenesis. Behavioral outcomes included are overall neurological function, motor function, cognitive function, frontal lobe function, and stress-related outcomes. A brief discussion is provided comparing the most common experimental models of TBI and highlighting the utility of each model in understanding specific aspects of TBI pathology. The majority of experimental TBI studies collect data in the acute postinjury period, but few continue into the chronic period. Available evidence from long-term studies suggests that many of the experimental TBI models can lead to progressive changes in histopathology and behavior. The studies described in this review contribute to our understanding of chronic TBI pathology.

The clinical and CT features of rapid spontaneous resolution of traumatic acute subdural hematoma: A retrospective study of 14 cases

OBJECTIVE

Resolution of a traumatic acute subdural haematoma (ASDH) requires weeks or months. However, cases of rapid spontaneous resolution of ASDH within 72 hours after trauma have been reported. The purpose of this study was to obtain a better understanding of the clinical and CT features of cases of rapid resolution following traumatic ASDH.

METHOD

Between 2011-2014, the authors retrospectively collected data from 14 patients with rapid resolution of traumatic ASDH. The clinical data and CT findings of these cases were collected and analysed.

RESULTS

In 13 of the 14 patients, there was a rapid spontaneous resolution of the ASDH within 48 hours. The mean haematoma width of the second CT was significantly smaller than the width of the initial CT. A significantly marked resolution of the midline shift was observed in the second CT in all patients. The outcome was good in the majority of patients.

CONCLUSIONS

The acute fluctuation of ICP may drive the spontaneous rapid resolution and redistribution of ASDH. Patients with abnormal coagulant function may be more likely to experience rapid resolution of ASDH. A band of low density in the initial CT image may be a useful sign for rapid resolution of ASDH.

Microparticles impact coagulation after traumatic brain injury

BACKGROUND

The pathophysiology that drives the subacute hypercoagulable state commonly seen after traumatic brain injury (TBI) is not well understood. Alterations caused by TBI in platelet and microparticle (MP) numbers and function have been suggested as possible causes; however, the contributions of platelets and MPs are currently unknown.

MATERIALS AND METHODS

A weight-drop technique of TBI using a murine model of moderate head injury was used. Blood was collected at intervals after injury. MP enumeration and characterization were performed using Nanoparticle Tracking Analysis, and platelet counts and coagulation parameters were determined using thromboelastometry. A MP procoagulant assay was used to compare activity between injured and sham mice.

RESULTS

At 24 h after injury, there were no changes in circulating platelet numbers. However, there was a decrease in platelet contribution to clot formation. In contrast, there was a decline in circulating total MP numbers. When MPs from sham mice were added to the blood from head-injured animals, there was a normalization of platelet contribution to clot formation. Conversely, when MPs from TBI mice were added to sham blood, there was a significant decrease in platelet contribution to clot formation. Notably, there was an increase in MP procoagulant activity in head-injured mice.

CONCLUSIONS

MPs generated after TBI likely contribute to altered coagulation after head injury and may play a key role in the development of a posttraumatic hypercoagulable state in TBI patients.

Clinical evidence of inflammation driving secondary brain injury: a systematic review

BACKGROUND

Despite advances in both prevention and treatment, traumatic brain injury (TBI) remains one of the most burdensome diseases; 2% of the US population currently lives with disabilities resulting from TBI. Recent advances in the understanding of inflammation and its impact on the pathophysiology of trauma have increased the interest in inflammation as a possible mediator in TBI outcome.

OBJECTIVES

The goal of this systematic review is to address the question: "What is the evidence in humans that inflammation is linked to secondary brain injury?" As the experimental evidence has been well described elsewhere, this review will focus on the clinical evidence for inflammation as a mechanism of secondary brain injury.

DATA SOURCES

Medline database (1996-Week 1 June 2014), Pubmed and Google Scholar databases were queried for relevant studies.

STUDY ELIGIBILITY CRITERIA

Studies were eligible if participants were adults and/or children who sustained moderate or severe TBI in the acute phase of injury, published in English. Studies published in the last decade (since 2004) were preferentially included. Trials could be observational or interventional in nature.

APPRAISAL AND SYNTHESIS METHODS

To address the quality of the studies retrieved, we applied the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) criteria to assess the limitations of the included studies.

RESULTS

Trauma initiates local central nervous system as well as systemic immune activation. Numerous observational studies describe elevation of pro-inflammatory cytokines that are associated with important clinical variables including neurologic outcome and mortality. A small number of clinical trials have included immunomodulating strategies, but no intervention to date has proven effective in improving outcomes after TBI.

LIMITATIONS

Inclusion of studies not initially retrieved by the search terms may have biased our results. Additionally, some reports may have been inadvertently excluded due to use of non-search term key words. Conclusions and Implications of Key Findings Clinical evidence of inflammation causing secondary brain injury in humans is gaining momentum. While inflammation is certainly present, it is not clear from the literature at what juncture inflammation becomes maladaptive, promoting secondary injury rather than facilitating repairand identifying patients with maladaptive inflammation (neuro-inflammation, systemic, or both) after TBI remains elusive. Direct agonism/antagonism represents an exciting target for future study.

LEVEL OF EVIDENCE

Systematic review, level III.

Viral immune surveillance: Toward a TH17/TH9 gate to the central nervous system

Viral cellular immune surveillance is a dynamic and fluid system that is driven by finely regulated cellular processes including cytokines and other factors locally in the microenvironment and systemically throughout the body. It is questionable as to what extent the central nervous system (CNS) is an immune-privileged organ protected by the blood-brain barrier (BBB). Recent evidence suggests converging pathways through which viral infection, and its associated immune surveillance processes, may alter the integrity of the blood-brain barrier, and lead to inflammation, swelling of the brain parenchyma and associated neurological syndromes. Here, we expand upon the recent "gateway theory", by which viral infection and other immune activation states may disrupt the specialized tight junctions of the BBB endothelium making it permeable to immune cells and factors. The model we outline here builds upon the proposition that this process may actually be initiated by cytokines of the IL-17 family, and recognizing the intimate balance between TH17 and TH9 cytokine profiles systemically. We argue that immune surveillance events, in response to viruses such as the Human Immunodeficiency Virus (HIV), cause a TH17/TH9 induced gateway through blood brain barrier, and thus lead to characteristic neuroimmune pathology. It is possible and even probable that the novel TH17/TH9 induced gateway, which we describe here, opens as a consequence of any state of immune activation and sustained chronic inflammation, whether associated with viral infection or any other cause of peripheral or central neuroinflammation. This view could lead to new, timely and critical patient-centered therapies for patients with neuroimmune pathologies across a variety of etiologies.

ABBREVIATIONS

BBB - blood brain barrier, BDV - Borna disease virus, CARD - caspase activation and recruitment domains, CD - clusters of differentiation, CNS - central nervous system, DAMP - damage-associated molecular patterns, DENV - Dengue virus, EBOV - Ebola virus, ESCRT - endosomal sorting complex required for transport-I, HepC - Hepatitis C virus, HIV - human immunodeficiency virus, IFN - interferon, ILn - interleukin-n, IRF-n - interferon regulatory factor-n, MAVS - mitochondrial antiviral-signaling, MBGV - Marburg virus, M-CSF - macrophage colony-stimulating factor, MCP-1 - monocyte chemotactic protein 1 (aka CCL2), MHC - major histocompatibility complex, MIP-α β - macrophage inflammatory protein-1 α β (aka CCL3 & CCL4), MIF - macrophage migration inhibitory factor, NVE - Nipah virus encephalitis, NK - natural killer cell, NLR - NLR, NOD - like receptor, NOD - nucleotide oligomerization domain, PAMP - pathogen-associated molecular patterns, PtdIns - phosphoinositides, PV - Poliovirus, RIG-I - retinoic acid-inducible gene I, RIP - Receptor-interacting protein (RIP) kinase, RLR - RIG-I-like receptor, sICAM1 - soluble intracellular adhesion molecule 1, STAT-3 - signal tranducer and activator of transcription-3, sVCAM1 - soluble vascular cell adhesion molecule 1, TANK - TRAF family member-associated NF- . B activator, TBK1 - TANK-binding kinase 1, TLR - Toll-like receptor, TNF - tumor necrosis factor, TNFR - TNF receptor, TNFRSF21 - tumor necrosis factor receptor superfamily member 21, TRADD TNFR-SF1A - associated via death domain, TRAF TNFR - associated factor, Tregs - regulatory T cellsubpopulation (CD4/8+CD25+FoxP3+), VHF - viral hemorrhagic fever.

Ebola: translational science considerations

We are currently in the midst of the most aggressive and fulminating outbreak of Ebola-related disease, commonly referred to as "Ebola", ever recorded. In less than a year, the Ebola virus (EBOV, Zaire ebolavirus species) has infected over 10,000 people, indiscriminately of gender or age, with a fatality rate of about 50%. Whereas at its onset this Ebola outbreak was limited to three countries in West Africa (Guinea, where it was first reported in late March 2014, Liberia, where it has been most rampant in its capital city, Monrovia and other metropolitan cities, and Sierra Leone), cases were later reported in Nigeria, Mali and Senegal, as well as in Western Europe (i.e., Madrid, Spain) and the US (i.e., Dallas, Texas; New York City) by late October 2014. World and US health agencies declared that the current Ebola virus disease (EVD) outbreak has a strong likelihood of growing exponentially across the world before an effective vaccine, treatment or cure can be developed, tested, validated and distributed widely. In the meantime, the spread of the disease may rapidly evolve from an epidemics to a full-blown pandemic. The scientific and healthcare communities actively research and define an emerging kaleidoscope of knowledge about critical translational research parameters, including the virology of EBOV, the molecular biomarkers of the pathological manifestations of EVD, putative central nervous system involvement in EVD, and the cellular immune surveillance to EBOV, patient-centered anthropological and societal parameters of EVD, as well as translational effectiveness about novel putative patient-targeted vaccine and pharmaceutical interventions, which hold strong promise, if not hope, to curb this and future Ebola outbreaks. This work reviews and discusses the principal known facts about EBOV and EVD, and certain among the most interesting ongoing or future avenues of research in the field, including vaccination programs for the wild animal vectors of the virus and the disease from global translational science perspective.

Intensive Care Treatment in Traumatic Brain Injury

Head injury remains a serious public problem, especially in the young population. The understanding of the mechanism of secondary injury and the development of appropriate monitoring and critical care treatment strategies reduced the mortality of head injury. The pathophysiology, monitoring and treatment principles of head injury are summarised in this article.

Formation of microparticles in the injured brain of patients with severe isolated traumatic brain injury

The potential pathophysiological role of circulating microparticles (MPs) has been recognized in various conditions, such as cardiovascular and thrombotic diseases. Traumatic brain injury (TBI) has a complex pathophysiology that involves coagulopathy and inflammation. We investigated endothelial-, platelet-, and leukocyte-derived microparticles (EMPs, PMPs, and LMPs, respectively) in 16 patients with severe isolated TBI. Arterial and cerebrovenous samples were taken repeatedly, during 1-72 h after injury. Subpopulations of MPs, exposing tissue factor (TF) and P-selection, were also studied. MP counts in cerebrovenous samples, irrespective of cellular origin, were higher in TBI cases, compared to healthy controls (peak levels of EMPs were approximately 7 times higher, PMPs 1.4 times higher, and LMPs 2 times higher, respectively; p<0.001 for all). MP counts declined sharply from high levels shortly after the trauma toward slightly elevated levels 72 h later. EMPs and PMPs exposing TF, as well as PMPs exposing P-selection, showed a transcranial gradient with higher concentration in cerebrovenous, compared to arterial, samples. In contrast, LMPs exposing TF were higher in arterial samples, suggesting accumulation of LMPs in the brain. We conclude that the pattern of circulating MPs is altered after TBI. PMPs exposing P-selection and EMPs exposing TF seem to be generated in the injured brain, whereas LMPs exposing TF are accumulated. The pathophysiological significance of these changes in MP pattern in TBI should be further investigated. Including MPs exposing brain-specific antigens in the assessment of brain injury would give further information of origin and likely give additional information of the size of the injury, given that the MP phenotypes investigated in the present study are not brain-specific markers.

Coagulopathy associated with traumatic brain injury

Coagulopathy is often observed after traumatic brain injury (TBI), but the pathogenic mechanisms of this phenomenon remain elusive. Brain injury is the leading cause of trauma deaths, and the development of coagulopathy after TBI is associated with increased morbidity and mortality in these patients. The coagulopathy after TBI comprises a hypocoagulable and a hypercoagulable state with hemorrhagic and thrombotic phenotypes that are both associated with worse outcome. Some theories of its pathogenesis include massive release of tissue factor, altered protein C homeostasis, microparticle upregulation, and platelet hyperactivity. This article aims to examine the coagulopathy associated with blunt head injury, to review its effect on progression of hemorrhagic injury, and to discuss the possible relevant pathophysiological mechanisms.

The influence of hemocoagulation disorders on the development of posttraumatic cerebral infarction and outcome in patients with moderate or severe head trauma

Posttraumatic cerebral infarction (PTCI) is a severe secondary insult of head injury and often leads to a poor prognosis. Hemocoagulation disorder is recognized to have important effects on hemorrhagic or ischemic damages. We sought to assess if posttraumatic hemocoagulation disorders were associated with cerebral infarction, and evaluate their influence on outcome among patients with moderate or severe head trauma. In this study, PTCI was observed in 28 (10.57%) of the 265 patients within the first week after injury. In multivariate analysis, the thrombocytopenia (odds ratio (OR) 2.210, 95% confidence interval (CI) 1.065–4.674), abnormal prothrombin time (PT) (OR 3.241, 95% CI 1.090–7.648), D-dimer (>2 mg/L) (OR 7.260, 95% CI 1.822–28.076), or disseminated intravascular coagulation (DIC) scores (≥5) (OR 4.717, 95% CI 1.778–12.517) were each independently associated with an increased risk of PTCI. Admission Glasgow Coma Scale (GCS) score, abnormal activated partial thromboplastin time (APTT) and fibrinogen, and D-dimer (>2 mg/L) and DIC scores (≥5) showed an independent predictive effect on poor outcome. In conclusion, recognition of this important treatable cause of PTCI and the associated risk factors may help identify the group at risk and tailor management of patients with TBI.

Prevention of venous thrombotic events in brain injury: review of current practices

Venous thromboembolic event after traumatic brain injury represents a unique clinical challenge. Physicians must balance appropriate timing of chemoprophylaxis with risk of increased cerebral hemorrhage. Despite an increase in the literature since the 1990s, there are clear disparities in treatment strategies. This review discusses the prominent studies and subsequent findings regarding the topic with an attempt to establish recommendations using the existing evidence-based literature.

Risk factors for vascular occlusive events and death due to bleeding in trauma patients; an analysis of the CRASH-2 cohort

BACKGROUND

Vascular occlusive events can complicate recovery following trauma. We examined risk factors for venous and arterial vascular occlusive events in trauma patients and the extent to which the risk of vascular occlusive events varies with the severity of bleeding.

METHODS AND FINDINGS

We conducted a cohort analysis using data from a large international, double-blind, randomised, placebo-controlled trial (The CRASH-2 trial) [1]. We studied the association between patient demographic and physiological parameters at hospital admission and the risk of vascular occlusive events. To assess the extent to which risk of vascular occlusive events varies with severity of bleeding, we constructed a prognostic model for the risk of death due to bleeding and assessed the relationship between risk of death due to bleeding and risk of vascular occlusive events. There were 20,127 trauma patients with outcome data including 204 (1.01%) patients with a venous event (pulmonary embolism or deep vein thrombosis) and 200 (0.99%) with an arterial event (myocardial infarction or stroke). There were 81 deaths due to vascular occlusive events. Increasing age, decreasing systolic blood pressure, increased respiratory rates, longer central capillary refill times, higher heart rates and lower Glasgow Coma Scores (all p<0.02) were strong risk factors for venous and arterial vascular occlusive events. Patients with more severe bleeding as assessed by predicted risk of haemorrhage death had a greatly increased risk for all types of vascular occlusive event (all p<0.001).

CONCLUSIONS

Patients with severe traumatic bleeding are at greatly increased risk of venous and arterial vascular occlusive events. Older age and blunt trauma are also risk factors for vascular occlusive events. Effective treatment of bleeding may reduce venous and arterial vascular occlusive complications in trauma patients.

The impact of coagulopathy on the outcome of traumatic epidural hematoma

PURPOSE

To evaluate the impact of trauma-associated coagulation disorders on the neurological outcome in patients with traumatic epidural hematoma undergoing surgical or non-surgical treatment. A retrospective analysis was performed using prospectively collected data in a consecutive patient series from a level 1 trauma center.

METHODS

Eighty-five patients with traumatic epidural hematoma were identified out of 1,633 patients admitted to our emergency room with traumatic head injuries between October 2004 and December 2008. The following prospectively assessed parameters were analyzed: Glasgow Coma Scale, coagulopathy, presence of skull fractures, additional injuries, the Injury Severity Score, hematoma volume and thickness at admission, hematoma volume progression over time and neurologic symptoms. Furthermore, patients were grouped based on whether they had undergone surgical or non-surgical treatment of the epidural hematoma. Clinical outcome was determined according to the Glasgow Outcome Score (GOS) at hospital discharge.

RESULTS

Patients with coagulopathy showed significantly lower GOS values compared to patients with intact blood coagulation. Initial and progressive hematoma volumes did not influence neurological outcome. Patients with multiple injuries did not show a worse outcome compared to those with isolated epidural hematoma. There was no difference in patient's outcome after surgical or non-surgical treatment.

CONCLUSIONS

Poor outcome after traumatic epidural hematoma was associated with coagulopathy. Progression of epidural hematoma volume was not associated with coagulopathy or with poor neurological outcome. Prospective studies are needed to confirm these results.

Coagulopathy after traumatic brain injury

Traumatic brain injury has long been associated with abnormal coagulation parameters, but the exact mechanisms underlying this phenomenon are poorly understood. Coagulopathy after traumatic brain injury includes hypercoagulable and hypocoagulable states that can lead to secondary injury by either the induction of microthrombosis or the progression of hemorrhagic brain lesions. Multiple hypotheses have been proposed to explain this phenomenon, including the release of tissue factor, disseminated intravascular coagulation, hyperfibrinolysis, hypoperfusion with protein C activation, and platelet dysfunction. The diagnosis and management of these complex patients are difficult given the lack of understanding of the underlying mechanisms. The goal of this review is to summarize the current knowledge regarding the mechanisms of coagulopathy after blunt traumatic brain injury. The current and emerging diagnostic tools, radiological findings, treatment options, and prognosis are discussed.

Cytokines and innate inflammation in the pathogenesis of human traumatic brain injury

There is an increasing recognition that following traumatic brain injury, a cascade of inflammatory mediators is produced, and contributes to the pathological consequences of central nervous system injury. This review summarises the key literature from pre-clinical models that underlies our understanding of innate inflammation following traumatic brain injury before focussing on the growing evidence from human studies. In addition, the underlying molecular mediators responsible for blood brain barrier dysfunction have been discussed. In particular, we have highlighted the different sampling methodologies available and the difficulties in interpreting human data of this sort. Ultimately, understanding the innate inflammatory response to traumatic brain injury may provide a therapeutic avenue in the treatment of central nervous system disease.

Arachnoid cell involvement in the mechanism of coagulation-initiated inflammation in the subarachnoid space after subarachnoid hemorrhage

OBJECTIVE

To assess if arachnoid cells have the capability to present antigen and activate T-lymphocytes after stimulation by bloody cerebrospinal fluid (CSF), and to illuminate the mechanism of coagulation-initiated inflammation in the subarachnoid space after subarachnoid hemorrhage (SAH).

METHODS

Arachnoid cells were cultured, characterized, and examined by immunofluorescence for the basal expression of human leukocyte antigen-DR (HLA-DR). Expression of HLA-DR, after co-culturing arachnoid cells in vitro with bloody CSF, was investigated by immunofluorescence and flow cytometry (FCM). The variation of arachnoid cells' ultrastructure was observed by transmission electron microscope (TEM). Arachnoid cells were co-cultured with peripheral blood mononuclear cells (PBMCs). The content of soluble interleukin-2 receptor (sIL-2r) in culture medium was detected by enzyme-linked immunosorbent assay (ELISA).

RESULTS

(1) Arachnoid cells were successfully cultured for many passages. The immunofluorescent staining was positive for HLA-DR in over 95% of the human arachnoid cells. The punctate HLA-DR was distributed in cytoplasm and not in the karyon. (2) After co-culturing arachnoid cells in vitro with bloody CSF, numerous particles with strong fluorescence appeared in the cytoplasm on Day 6. On Day 8, the quantity of particles and fluorescent intensity were maximal. FCM showed that the percentage of HLA-DR expressing cells was (2.5+/-0.4)% at the first 5 d, increasing to (60.8+/-3.6)% on Day 7. (3) After co-culturing arachnoid cells in vitro with bloody CSF, many lysosome and secondary lysosome particles were present in the cytoplasm. Hyperplasia of rough endoplasmic reticulum and enlarged cysts were observed, with numerous phagocytizing vesicles also observed at the edge of the arachnoid cells. (4) Arachnoid cells stimulated by bloody CSF were co-cultured in vitro with PBMCs. The content of sIL-2r in the culture medium, having been maintained at around 1.30 ng/ml during the first 3 d, had increased by Day 4. The content of sIL-2r peaked 7.53 ng/ml on Day 7 and then reduced gradually.

CONCLUSIONS

(1) Basic HLA-DR expression is present in arachnoid cells. (2) After stimulation by bloody CSF, arachnoid cells have the potential to serve as antigen presenting cells (APCs) and the ability to activate T-lymphocytes, indicating that arachnoid cells are involved in the mechanism of coagulation-initiated inflammation in the subarachnoid space after SAH.

[Coagulation disorders after traumatic brain injury: pathophysiology and therapeutic implications]

Early activation of coagulation is common after traumatic brain injury. Its origin is probably mainly intracerebral, due to tissue factor release from the injured brain. Abnormalities in blood coagulation tests are associated with poor neurological prognosis. Coagulation activation may induce disseminated intravascular coagulation and fibrinolysis. Disseminated intravascular coagulation is linked to brain ischemia caused by intravascular microthrombosis. This review will focus on pathophysiology of coagulation disorders after traumatic brain injury, and on their implications for therapeutic approaches.

Blood-brain barrier breakdown as a therapeutic target in traumatic brain injury

Traumatic brain injury (TBI) is the leading cause of death in young adults and children. The treatment of TBI in the acute phase has improved substantially; however, the prevention and management of long-term complications remain a challenge. Blood-brain barrier (BBB) breakdown has often been documented in patients with TBI, but the role of such vascular pathology in neurological dysfunction has only recently been explored. Animal studies have demonstrated that BBB breakdown is involved in the initiation of transcriptional changes in the neurovascular network that ultimately lead to delayed neuronal dysfunction and degeneration. Brain imaging data have confirmed the high incidence of BBB breakdown in patients with TBI and suggest that such pathology could be used as a biomarker in the clinic and in drug trials. Here, we review the neurological consequences of TBI, focusing on the long-term complications of such injuries. We present the clinical evidence for involvement of BBB breakdown in TBI and examine the primary and secondary mechanisms that underlie such pathology. We go on to consider the consequences of BBB injury, before analyzing potential mechanisms linking vascular pathology to neuronal dysfunction and degeneration, and exploring possible targets for treatment. Finally, we highlight areas for future basic research and clinical studies into TBI.

What has inflammation to do with traumatic brain injury?

INTRODUCTION

Inflammation is an stereotypical response to tissue damage and has been extensively documented in experimental and clinical traumatic brain injury (TBI), including children.

DISCUSSION

The initiation and orchestration of inflammation in TBI, as in other tissues, is complex and multifactorial encompassing pro- and anti-inflammatory cytokines, chemokines, adhesion molecules, complement factors, reactive oxygen and nitrogen species, and other undefined factors. It is evident that inflammation can have both beneficial and detrimental effects in TBI, but the mechanisms underlying this dichotomy are mostly unknown. Modification of the inflammatory response may be neuroprotective. Monitoring inflammation is now possible with techniques such as microdialysis; however, the prognostic value of measuring inflammatory mediators in TBI is still unclear with conflicting reports. Except for corticosteroids, no anti-inflammatory agents have been tested in TBI, and the negative results with these may have been flawed by their multiple side effects. Clinical trials with anti-inflammatory agents that target multiple or central and downstream pathways are warranted in adult and pediatric TBI. This review examines the mechanisms of inflammation after TBI, monitoring, and possible routes of intervention.

Traumatic brain injury is associated with the development of deep vein thrombosis independent of pharmacological prophylaxis

INTRODUCTION

Deep venous thrombosis (DVT) is common among trauma patients. If left untreated it may result in lethal pulmonary thromboembolism. Previous studies have suggested that intracranial hemorrhage serves as an independent risk factor for the development of DVT. These studies were not able to exclude anticoagulation therapy as a confounding variable in their analysis. Our objective was to determine the association of traumatic brain injury (TBI) to the formation of DVT irrespective of the use of anticoagulation therapy.

METHODS

All patients admitted to an academic level I Trauma Center between 2000 and 2007 with blunt or penetrating injuries were selected for inclusion in this study. Patients who died or who were discharged within 24 hours of admission were excluded in the analysis. TBI was defined as any intraparenchymal hemorrhage or extra-axial intracranial bleeding identified on radiographic imaging or both. Anticoagulation therapy was defined as the uninterrupted use of either subcutaneous lovenox or heparin. Risk ratios and 95% confidence intervals compared the risk of DVT among patients with and without TBI according to the initiation of anticoagulation therapy (no therapy, <24 hours, 24-48 hours, and >48 hours) adjusted for age, gender, race, injury severity, mechanism of injury, spinal injury, and lower extremity fracture.

RESULTS

Irrespective of the time of initiation of pharmacologic prophylaxis, TBI is independently associated with the formation of DVT. A threefold to fourfold increased risk of DVT formation is consistent across all prophylaxis groups among patients with TBI.

CONCLUSION

The incidence of DVT among injured patients with TBI is significantly higher than those patients without head injury independent of anticoagulation therapy. Rigorous surveillance to detect DVT among trauma patients with TBI should be undertaken and where appropriate alternate means for pulmonary thromboembolism prevention used.

Signal transduction pathways involved in brain death-induced renal injury

Kidneys derived from brain death organ donors show an inferior survival when compared to kidneys derived from living donors. Brain death is known to induce organ injury by evoking an inflammatory response in the donor. Neuronal injury triggers an inflammatory response in the brain, leading to endothelial dysfunction and the release of cytokines in the circulation. Serum levels of interleukin-6, -8, -10, and monocyte chemoattractant protein-1 (MCP-1) are increased after brain death. Binding with cytokine-receptors in kidneys stimulates activation of nuclear factor-kappa B (NF-kappaB), selectins, adhesion molecules and production of chemokines leading to cellular influx. Mitogen-activated protein kinases (MAP-kinases) mediate inflammatory responses and together with NF-kappaB they seem to play an important role in brain death induced renal injury. Altering the activation state of MAP-kinases could be a promising drug target for early intervention to reduce cerebral injury related donor kidney damage and improve outcome after transplantation.