Fresh Frozen Plasma Modulates Brain Gene Expression in a Swine Model of Traumatic Brain Injury and Shock: A Network Analysis

Insights from CTTACC: immune system reset by cellular therapies for chronic illness after trauma, infection, and burn

BACKGROUND AIMS

In this paper, we present a review of several selected talks presented at the CTTACC conference (Cellular Therapies in Trauma and Critical Care) held in Scottsdale, AZ in May 2023. This conference review highlights the potential for cellular therapies to "reset" the dysregulated immune response and restore physiologic functions to normal. Improvements in medical care systems and technology have increasingly saved lives after major traumatic events. However, many of these patients have complicated post-traumatic sequelae, ranging from short-term multi-organ failure to chronic critical illness.

METHODS/RESULTS

Patients with chronic critical illness have been found to have dysregulated immune responses. These abnormal and harmful immune responses persist for years after the initial insult and can potentially be mitigated by treatment with cellular therapies.

CONCLUSIONS

The sessions emphasized the need for more research and clinical trials with cellular therapies for the treatment of a multitude of chronic illnesses: post-trauma, radiation injury, COVID-19, burns, traumatic brain injury (TBI) and other chronic infections.

Acute Haemostatic Depletion and Failure in Patients with Traumatic Brain Injury (TBI): Pathophysiological and Clinical Considerations

BACKGROUND

Because of the aging population, the number of low falls in elderly people with pre-existing anticoagulation is rising, often leading to traumatic brain injury (TBI) with a social and economic burden. Hemostatic disorders and disbalances seem to play a pivotal role in bleeding progression. Interrelationships between anticoagulatoric medication, coagulopathy, and bleeding progression seem to be a promising aim of therapy.

METHODS

We conducted a selective search of the literature in databases like Medline (Pubmed), Cochrane Library and current European treatment recommendations using relevant terms or their combination.

RESULTS

Patients with isolated TBI are at risk for developing coagulopathy in the clinical course. Pre-injury intake of anticoagulants is leading to a significant increase in coagulopathy, so every third patient with TBI in this population suffers from coagulopathy, leading to hemorrhagic progression and delayed traumatic intracranial hemorrhage. In an assessment of coagulopathy, viscoelastic tests such as TEG or ROTEM seem to be more beneficial than conventional coagulation assays alone, especially because of their timely and more specific gain of information about coagulopathy. Furthermore, results of point-of-care diagnostic make rapid "goal-directed therapy" possible with promising results in subgroups of patients with TBI.

CONCLUSIONS

The use of innovative technologies such as viscoelastic tests in the assessment of hemostatic disorders and implementation of treatment algorithms seem to be beneficial in patients with TBI, but further studies are needed to evaluate their impact on secondary brain injury and mortality.

Factors Associated with the Development of Coagulopathy after Open Traumatic Brain Injury

Background: The incidence of coagulopathy after open traumatic brain injury (TBI) is high. Coagulopathy can aggravate intracranial hemorrhage and further increase morbidity and mortality. The purpose of this study was to determine the clinical characteristics of coagulopathy after open TBI and its relationship with the prognosis. Methods: This study retrospectively evaluated patients with isolated open TBI from December 2018 to December 2020. Coagulopathy was defined as international normalized ratio (INR) > 1.2, activated thromboplastin time (APTT) > 35 s, or platelet count <100,000/μL. We compared the relationship between the clinical, radiological, and laboratory parameters of patients with and without coagulopathy, and the outcome at discharge. Logistic regression analysis was used to evaluate the risk factors associated with coagulopathy. We then compared the effects of treatment with and without TXA in open TBI patients with coagulopathy. Results: A total of 132 patients were included in the study; 46 patients developed coagulopathy. Patients with coagulopathy had significantly lower platelet levels (170.5 × 10⁹/L vs. 216.5 × 10⁹/L, p < 0.001), and significantly higher INR (1.14 vs. 1.02, p < 0.001) and APTT (30.5 s vs. 24.5 s, p < 0.001) compared to those with no coagulopathy. A Low Glasgow Coma Scale (GCS) score, high neutrophil/lymphocyte ratio (NLR), low platelet/lymphocyte ratio (PLR), and hyperglycemia at admission were significantly associated with the occurrence of coagulopathy. Conclusions: Coagulopathy often occurs after open TBI. Patients with a low GCS score, high NLR, low PLR, and hyperglycemia at admission are at greater risk of coagulopathy, and therefore of poor prognosis. The efficacy of TXA in open TBI patients with coagulopathy is unclear. In addition, these findings demonstrate that PLR may be a novel indicator for predicting coagulopathy.

Coagulopathy and Progression of Intracranial Hemorrhage in Traumatic Brain Injury: Mechanisms, Impact, and Therapeutic Considerations

BACKGROUND

Traumatic brain injury (TBI) remains one of the most challenging health and socioeconomic problems of our times. Clinical courses may be complicated by hemostatic abnormalities either pre-existing or developing with TBI.

OBJECTIVE

To review frequencies, patterns, mechanisms, novel approaches to diagnostics, treatment, and outcomes of hemorrhagic progression and coagulopathy after TBI.

METHODS

Selective review of the literature in the databases Medline (PubMed) and Cochrane Reviews using different combinations of the relevant search terms was conducted.

RESULTS

Of the patients, 20% with isolated TBI display laboratory coagulopathy upon hospital admission with profound effect on morbidity and mortality. Preinjury use of antithrombotic agents may be associated with higher rates of hemorrhagic progression and delayed traumatic intracranial hemorrhage. Further testing may display various changes affecting platelet function/numbers, pro- and/or anticoagulant factors, and fibrinolysis as well as interactions between brain tissues, vascular endothelium, mechanisms of inflammation, and blood flow dynamics. The nature of hemostatic disruptions after TBI remains elusive but current evidence suggests the presence of both a hyper- and hypocoagulable state with possible overlap and lack of distinction between phases and states. More "global" hemostatic assays, eg, viscoelastic and thrombin generation tests, may provide more detailed and timely information on the overall hemostatic potential thereby allowing early "goal-directed" therapies.

CONCLUSION

Whether timely and targeted management of hemostatic abnormalities after TBI can protect against secondary brain injury and thereby improve outcomes remains elusive. Innovative technologies for diagnostics and monitoring offer windows of opportunities for precision medicine approaches to managing TBI.

Traumatic Brain Injury-A Review of Intravenous Fluid Therapy

This manuscript will review intravenous fluid therapy in traumatic brain injury. Both human and animal literature will be included. Basic treatment recommendations will also be discussed.

Modulation of Brain Transcriptome by Combined Histone Deacetylase Inhibition and Plasma Treatment Following Traumatic Brain Injury and Hemorrhagic Shock

INTRODUCTION

We previously showed that the addition of valproic acid (VPA), a histone deacetylase inhibitor, to fresh frozen plasma (FFP) resuscitation attenuates brain lesion size and swelling following traumatic brain injury (TBI) and hemorrhagic shock (HS). The goal of this study was to use computational biology tools to investigate the effects of FFP+VPA on the brain transcriptome following TBI+HS.

METHODS

Swine underwent TBI+HS, kept in shock for 2 h, and resuscitated with FFP or FFP + VPA (n = 5/group). After 6 h of observation, brain RNA was isolated and gene expression was analyzed using a microarray. iPathwayGuide, Gene Ontology (GO), Gene-Set Enrichment Analysis, and Enrichment Mapping were used to identify significantly impacted genes and transcriptomic networks.

RESULTS

Eight hundred differentially expressed (DE) genes were identified out of a total of 9,118 genes. Upregulated genes were involved in promotion of cell division, proliferation, and survival, while downregulated genes were involved in autophagy, cell motility, neurodegenerative diseases, tumor suppression, and cell cycle arrest. Seven hundred ninety-one GO terms were significantly enriched. A few major transcription factors, such as TP53, NFKB3, and NEUROD1, were responsible for modulating hundreds of other DE genes. Network analysis revealed attenuation of interconnected genes involved in inflammation and tumor suppression, and an upregulation of those involved in cell proliferation and differentiation.

CONCLUSION

Overall, these results suggest that VPA treatment creates an environment that favors production of new neurons, removal of damaged cells, and attenuation of inflammation, which could explain its previously observed neuroprotective effects.

Transfusion Strategies are Associated with Epigenetic Changes Following Blunt Trauma

INTRODUCTION

Epigenetics has been identified in multiple diseases. The effect of transfusion strategy on epigenetics is unknown. We hypothesized that expression of epigenetic regulating genes would be associated with resuscitation strategy following blunt trauma.

METHODS

Retrospective study using the inflammation in host response to injury (glue grant) dataset. Volume transfused over 24 h of packed red blood cells (PRBC), fresh frozen plasma (FFP), platelets (PLT) as well as crystalloids was extracted along with leucocyte microarray data of genes with known epigenetic modulating activity from day 1 after injury.Principal component analysis (PCA) was used to identify principal components (PC) within the transcriptomic dataset. Multiple regression associated these with volume of blood products and crystalloids while controlling for confounders. Genes co-expressed with genes central genes in the identified PCs were furthermore subjected to pathway analysis using the reactome database.

RESULTS

PCA identified seven components. PRBC and crystalloid volumes were positively associated with PC1, implicating histone acetylation (HAT1), DNA and histone methylation (KDM6B, SET1DB) and histone phosphorylation (RPS6KA5). Conversely, PLT volume was negatively associated with PC1,5 and 6, implicating DNA methylation (DNMT1) as well as histone acetylation (HAT1) and phosphorylation (RPSKA3).FFP was negatively associated with PC3, implicating histone methylation (SETD1B) and phosphorylation (RPS6KA5).Co-expression network analysis identified downstream pathways relevant to inflammation and the innate immune response, including Toll-like receptor, interleukin and mitogen activated protein kinase activation.

CONCLUSIONS

Resuscitation strategy was associated with epigenetic transcriptomic alterations, especially for PRBC and PLT transfusions. Downstream effects may include pertubations of pathways involved in immune signaling and cellular survival.

A systematic review of large animal models of combined traumatic brain injury and hemorrhagic shock

Traumatic brain injury (TBI) and severe blood loss (SBL) frequently co-occur in human trauma, resulting in high levels of mortality and morbidity. Importantly, each of the individual post-injury cascades is characterized by complex and potentially opposing pathophysiological responses, complicating optimal resuscitation and therapeutic approaches. Large animal models of poly-neurotrauma closely mimic human physiology, but a systematic literature review of published models has been lacking. The current review suggests a relative paucity of large animal poly-neurotrauma studies (N = 52), with meta-statistics revealing trends for animal species (exclusively swine), characteristics (use of single biological sex, use of juveniles) and TBI models. Although most studies have targeted blood loss volumes of 35-45%, the associated mortality rates are much lower relative to Class III/IV human trauma. This discrepancy may result from potentially mitigating experimental factors (e.g., mechanical ventilation prior to or during injury, pausing/resuming blood loss based on physiological parameters, administration of small volume fluid resuscitation) that are rarely associated with human trauma, highlighting the need for additional work in this area.

Different resuscitation strategies and novel pharmacologic treatment with valproic acid in traumatic brain injury

Traumatic brain injury (TBI) is a leading cause of death in young adults, and effective treatment strategies have the potential to save many lives. TBI results in coagulopathy, endothelial dysfunction, inflammation, cell death, and impaired epigenetic homeostasis, ultimately leading to morbidity and/or mortality. Commonly used resuscitation fluids such as crystalloids or colloids have several disadvantages and might even be harmful when administered in large quantities. There is a need for next-generation treatment strategies (especially in the prehospital setting) that minimize cellular damage, improve survival, and enhance neurological recovery. Pharmacologic treatment with histone deacetylase inhibitors, such as valproic acid, has shown promising results in animal studies of TBI and may therefore be an excellent example of next-generation therapy. This review briefly describes traditional resuscitation strategies for TBI combined with hemorrhagic shock and describes preclinical studies on valproic acid as a new pharmacologic agent in the treatment of TBI. It finally discusses limitations and future directions on the use of histone deacetylase inhibitors for the treatment of TBI.

Outcomes after concomitant traumatic brain injury and hemorrhagic shock: A secondary analysis from the Pragmatic, Randomized Optimal Platelets and Plasma Ratios trial

BACKGROUND

Often the clinician is faced with a diagnostic and therapeutic dilemma in patients with concomitant traumatic brain injury (TBI) and hemorrhagic shock (HS), as rapid deterioration from either can be fatal. Knowledge about outcomes after concomitant TBI and HS may help prioritize the emergent management of these patients. We hypothesized that patients with concomitant TBI and HS (TBI + HS) had worse outcomes and required more intensive care compared with patients with only one of these injuries.

METHODS

This is a post hoc analysis of the Pragmatic, Randomized Optimal Platelets and Plasma Ratios (PROPPR) trial. TBI was defined by a head Abbreviated Injury Scale score greater than 2. HS was defined as a base excess of -4 or less and/or shock index of 0.9 or greater. The primary outcome for this analysis was mortality at 30 days. Logistic regression, using generalized estimating equations, was used to model categorical outcomes.

RESULTS

Six hundred seventy patients were included. Patients with TBI + HS had significantly higher lactate (median, 6.3; interquartile range, 4.7-9.2) compared with the TBI group (median, 3.3; interquartile range, 2.3-4). TBI + HS patients had higher activated prothrombin times and lower platelet counts. Unadjusted mortality was higher in the TBI + HS (51.6%) and TBI (50%) groups compared with the HS (17.5%) and neither group (7.7%). Adjusted odds of death in the TBI and TBI + HS groups were 8.2 (95% confidence interval, 3.4-19.5) and 10.6 (95% confidence interval, 4.8-23.2) times higher, respectively. Ventilator, intensive care unit-free and hospital-free days were lower in the TBI and TBI + HS groups compared with the other groups. Patients with TBI + HS or TBI had significantly greater odds of developing a respiratory complication compared with the neither group.

CONCLUSION

The addition of TBI to HS is associated with worse coagulopathy before resuscitation and increased mortality. When controlling for multiple known confounders, the diagnosis of TBI alone or TBI+HS was associated with significantly greater odds of developing respiratory complications.

LEVEL OF EVIDENCE

Prognostic study, level II.

Prehospital plasma resuscitation associated with improved neurologic outcomes after traumatic brain injury

BACKGROUND

Trauma-related hypotension and coagulopathy worsen secondary brain injury in patients with traumatic brain injuries (TBIs). Early damage control resuscitation with blood products may mitigate hypotension and coagulopathy. Preliminary data suggest resuscitation with plasma in large animals improves neurologic function after TBI; however, data in humans are lacking.

METHODS

We retrospectively identified all patients with multiple injuries age >15 years with head injuries undergoing prehospital resuscitation with blood products at a single Level I trauma center from January 2002 to December 2013. Inclusion criteria were prehospital resuscitation with either packed red blood cells (pRBCs) or thawed plasma as sole colloid resuscitation. Patients who died in hospital and those using anticoagulants were excluded. Primary outcomes were Glasgow Outcomes Score Extended (GOSE) and Disability Rating Score (DRS) at dismissal and during follow-up.

RESULTS

Of 76 patients meeting inclusion criteria, 53% (n = 40) received prehospital pRBCs and 47% (n = 36) received thawed plasma. Age, gender, injury severity or TBI severity, arrival laboratory values, and number of prehospital units were similar (all p > 0.05). Patients who received thawed plasma had an improved neurologic outcome compared to those receiving pRBCs (median GOSE 7 [7-8] vs. 5.5 [3-7], p < 0.001). Additionally, patients who received thawed plasma had improved functionality compared to pRBCs (median DRS 2 [1-3.5] vs. 9 [3-13], p < 0.001). Calculated GOSE and DRS scores during follow-up, median 6 [5-7] months, demonstrated increased function in those resuscitated with thawed plasma compared to pRBCs by both median GOSE (8 [7-8] vs. 6 [6-7], p < 0.001) and DRS (0 [0-1] vs. 4 [2-8], p < 0.001).

CONCLUSION

In critically injured trauma patients with TBI, early resuscitation with thawed plasma is associated with improved neurologic and functional outcomes at discharge and during follow-up compared to pRBCs alone. These preliminary data support the further investigation and use of plasma in the resuscitation of critically injured TBI patients.

LEVEL OF EVIDENCE

Therapeutic, level V.

Resuscitation with Lyophilized Plasma Is Safe and Improves Neurological Recovery in a Long-Term Survival Model of Swine Subjected to Traumatic Brain Injury, Hemorrhagic Shock, and Polytrauma

We have shown previously that fresh frozen plasma (FFP) and lyophilized plasma (LP) decrease brain lesion size and improve neurological recovery in a swine model of traumatic brain injury (TBI) and hemorrhagic shock (HS). In this study, we examine whether these findings can be validated in a clinically relevant model of severe TBI, HS, and polytrauma. Female Yorkshire swine were subjected to TBI (controlled cortical impact), hemorrhage (40% volume), grade III liver and splenic injuries, rib fracture, and rectus abdominis crush. The animals were maintained in a state of shock (mean arterial pressure 30-35 mm Hg) for 2 h, and then randomized to resuscitation with normal saline (NS), FFP, or LP (n = 5 swine/group). Animals were recovered and monitored for 30 d, during which time neurological recovery was assessed. Brain lesion sizes were measured via magnetic resonance imaging (MRI) on post-injury days (PID) three and 10. Animals were euthanized on PID 30. The severity of shock and response to resuscitation was similar in all groups. When compared with NS-treated animals, plasma-treated animals (FFP and LP) had significantly lower neurologic severity scores (PID 1-7) and a faster return to baseline neurological function. There was no significant difference in brain lesion sizes between groups. LP treatment was well tolerated and similar to FFP. In this clinically relevant large animal model of severe TBI, HS, and polytrauma, we have shown that plasma-based resuscitation strategies are safe and result in neurocognitive recovery that is faster than recovery after NS-based resuscitation.