Early treatment with lyophilized plasma protects the brain in a large animal model of combined traumatic brain injury and hemorrhagic shock

THE NEUROENDOTHELIAL AXIS IN TRAUMATIC BRAIN INJURY: MECHANISMS OF MULTIORGAN DYSFUNCTION, NOVEL THERAPIES, AND FUTURE DIRECTIONS

ABSTRACT

Severe traumatic brain injury (TBI) often initiates a systemic inflammatory response syndrome, which can potentially culminate into multiorgan dysfunction. A central player in this cascade is endotheliopathy, caused by perturbations in homeostatic mechanisms governed by endothelial cells due to injury-induced coagulopathy, heightened sympathoadrenal response, complement activation, and proinflammatory cytokine release. Unique to TBI is the potential disruption of the blood-brain barrier, which may expose neuronal antigens to the peripheral immune system and permit neuroinflammatory mediators to enter systemic circulation, propagating endotheliopathy systemically. This review aims to provide comprehensive insights into the "neuroendothelial axis" underlying endothelial dysfunction after TBI, identify potential diagnostic and prognostic biomarkers, and explore therapeutic strategies targeting these interactions, with the ultimate goal of improving patient outcomes after severe 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.

Freeze-dried plasma for major trauma - Systematic review and meta-analysis

BACKGROUND

Treatment of acute trauma coagulopathy has shifted toward rapid replacement of coagulation factors with frozen plasma (FP). There are logistic difficulties in providing FP. Freeze-dried plasma (FDP) may have logistical advantages including easier storage and rapid preparation time. This review assesses the feasibility, efficacy, and safety of FDP in trauma.

STUDY DESIGN AND METHODS

Studies were searched from Medline, Embase, Cochrane Controlled Trials Register, ClinicalTrials.gov, and Google Scholar. Observational and randomized controlled trials (RCTs) assessing FDP use in trauma were included. Trauma animal models addressing FDP use were also included. Bias was assessed using validated tools. Primary outcome was efficacy, and secondary outcomes were feasibility and safety. Meta-analyses were conducted using random-effect models. Evidence was graded using Grading of Recommendations Assessment, Development, and Evaluation profile.

RESULTS

Twelve human studies (RCT, 1; observational, 11) and 15 animal studies were included. Overall, studies demonstrated moderate risk of bias. Data from two studies (n = 119) were combined for meta-analyses for mortality and transfusion of allogeneic blood products (ABPs). For both outcomes, no difference was identified. For mortality, pooled odds ratio was 0.66 (95% confidence interval, 0.29-1.49), with I2 = 0%. Use of FDP is feasible, and no adverse events were reported. Animal data suggest similar results for coagulation and anti-inflammatory profiles for FP and FDP.

CONCLUSION

Human data assessing FDP use in trauma report no difference in mortality and transfusion of ABPs in patients receiving FDP compared with FP. Data from animal trauma studies report no difference in coagulation factor and anti-inflammatory profiles between FP and FDP. Results should be interpreted with caution because most studies were observational and have heterogeneous population (military and civilian trauma) and a moderate risk of bias. Well-designed prospective observational studies or, preferentially, RCTs are warranted to answer FDP's effect on laboratory (coagulation factor levels), transfusion (number of ABPs), and clinical outcomes (organ dysfunction, length of stay, and mortality).

LEVEL OF EVIDENCE

Systematic review and meta-analysis, level IV.

Dysregulation of the actin scavenging system and inhibition of DNase activity following severe thermal injury

Background

Circulating cell‐free DNA (cfDNA) is not found in healthy subjects, but is readily detected after thermal injury and may contribute to the risk of multiple organ failure. The hypothesis was that a postburn reduction in DNase protein/enzyme activity could contribute to the increase in cfDNA following thermal injury.

Methods

Patients with severe burns covering at least 15 per cent of total body surface area were recruited to a prospective cohort study within 24 h of injury. Blood samples were collected from the day of injury for 12 months.

Results

Analysis of blood samples from 64 patients revealed a significant reduction in DNase activity on days 1–28 after injury, compared with healthy controls. DNase protein levels were not affected, suggesting the presence of an enzyme inhibitor. Further analysis revealed that actin (an inhibitor of DNase) was present in serum samples from patients but not those from controls, and concentrations of the actin scavenging proteins gelsolin and vitamin D‐binding protein were significantly reduced after burn injury. In a pilot study of ten military patients with polytrauma, administration of blood products resulted in an increase in DNase activity and gelsolin levels.

Conclusion

The results of this study suggest a novel biological mechanism for the accumulation of cfDNA following thermal injury by which high levels of actin released by damaged tissue cause a reduction in DNase activity. Restoration of the actin scavenging system could therefore restore DNase activity, and reduce the risk of cfDNA‐induced host tissue damage and thrombosis.

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.

Dried Plasma

Dried plasma provides an alternative for early plasma transfusion in the resuscitation of hemorrhagic shock in environments where fresh frozen plasma is not immediately available. It is produced by freeze-drying or spray-drying liquid or thawed plasma. It is shelf-stable for prolonged periods, can be stored at room temperature, and is easy to transport, reconstitute, and administer. It was widely used in WWII but fell out of favor due to the risk of infectious disease transmission. The German and French experiences with lyophilized plasma are the most extensive and show a good track record of efficacy and safety. Recent studies show many beneficial effects of dried plasma in the treatment of shock in large animal models. Currently, no FDA-licensed product is available in the USA, but several are under development.

Intracranial Pressure Monitoring in Experimental Traumatic Brain Injury: Implications for Clinical Management

Traumatic brain injury (TBI) is often associated with long-term disability and chronic neurological sequelae. One common contributor to unfavorable outcomes is secondary brain injury, which is potentially treatable and preventable through appropriate management of patients in the neurosurgical intensive care unit. Intracranial pressure (ICP) is currently the predominant neurological-specific physiological parameter used to direct the care of severe TBI (sTBI) patients. However, recent clinical evidence has called into question the association of ICP monitoring with improved clinical outcome. The detailed cellular and molecular derangements associated with intracranial hypertension (IC-HTN) and their relationship to injury phenotype and neurological outcomes are not completely understood. Various animal models of TBI have been developed, but the clinical applicability of ICP monitoring in the pre-clinical setting has not been well-characterized. Linking basic mechanistic studies in translational TBI models with investigation of ICP monitoring that more faithfully replicates the clinical setting will provide clinical investigators with a more informed understanding of the pathophysiology of IC-HTN, thus facilitating development of improved therapies for sTBI patients.

Rapid valproic acid-induced modulation of the traumatic proteome in a porcine model of traumatic brain injury and hemorrhagic shock

BACKGROUND

Histone deacetylase inhibitors such as valproic acid (VPA) improve survival in lethal models of hemorrhagic shock and polytrauma. Although VPA is known to modulate transcription, its ability to reduce mortality within minutes of administration suggests involvement of a rapid, posttranslational mechanism. We hypothesized that VPA treatment would cause proteomic changes within minutes of treatment including quantitative and/or posttranslational differences in structural and/or effector proteins.

MATERIALS AND METHODS

We used a porcine model of traumatic brain injury (computer-controlled cortical impact, 12 mm depth) and hemorrhagic shock (40% hemorrhage). Animals were kept in shock for 2 h and randomized to two groups (n = 3): normal saline (volume = 3:1 hemorrhage volume) or normal saline + VPA (150 mg/kg, single dose). Peripheral blood mononuclear cells were collected at baseline, postshock, and postresuscitation. Intracellular protein profiles were assessed using 1 dimensional gel electrophoresis, liquid chromatography, mass spectrometry, and analyzed with Ingenuity Pathway Analysis software.

RESULTS

Animals treated with VPA demonstrated significant proteomic changes. Quantitative differences were found in over 200 proteins including effector, regulatory, and structural proteins in critical cell signaling pathways. Posttranslational modification analysis demonstrated differential VPA-induced acetylation of lysine residues in histone and nonhistone proteins. Pathway analysis correlated these changes with significant increases in numerous prosurvival and cytoskeletal intracellular pathways, including Rho GTPase signaling (P = 1.66E-11), integrin signaling (P = 4.19E-21), and a decrease in Rho guanosine nucleotide dissociation inhibitor signaling (P = 4.83E-12).

CONCLUSIONS

In a porcine model of severe injuries, a single dose of VPA is associated with protective changes in the proteome that are measurable within minutes of treatment.

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.

Lyophilized plasma attenuates vascular permeability, inflammation and lung injury in hemorrhagic shock

In severe trauma and hemorrhage the early and empiric use of fresh frozen plasma (FFP) is associated with decreased morbidity and mortality. However, utilization of FFP comes with the significant burden of shipping and storage of frozen blood products. Dried or lyophilized plasma (LP) can be stored at room temperature, transported easily, reconstituted rapidly with ready availability in remote and austere environments. We have previously demonstrated that FFP mitigates the endothelial injury that ensues after hemorrhagic shock (HS). In the current study, we sought to determine whether LP has similar properties to FFP in its ability to modulate endothelial dysfunction in vitro and in vivo. Single donor LP was compared to single donor FFP using the following measures of endothelial cell (EC) function in vitro: permeability and transendothelial monolayer resistance; adherens junction preservation; and leukocyte-EC adhesion. In vivo, using a model of murine HS, LP and FFP were compared in measures of HS- induced pulmonary vascular inflammation and edema. Both in vitro and in vivo in all measures of EC function, LP demonstrated similar effects to FFP. Both FFP and LP similarly reduced EC permeability, increased transendothelial resistance, decreased leukocyte-EC binding and persevered adherens junctions. In vivo, LP and FFP both comparably reduced pulmonary injury, inflammation and vascular leak. Both FFP and LP have similar potent protective effects on the vascular endothelium in vitro and in lung function in vivo following hemorrhagic shock. These data support the further development of LP as an effective plasma product for human use after trauma and hemorrhagic shock.

Improvement of Blood-Brain Barrier Integrity in Traumatic Brain Injury and Hemorrhagic Shock Following Treatment With Valproic Acid and Fresh Frozen Plasma

OBJECTIVE

Combined traumatic brain injury and hemorrhagic shock are highly lethal. Following injuries, the integrity of the blood-brain barrier can be impaired, contributing to secondary brain insults. The status of the blood-brain barrier represents a potential factor impacting long-term neurologic outcomes in combined injuries. Treatment strategies involving plasma-based resuscitation and valproic acid therapy have shown efficacy in this setting. We hypothesize that a component of this beneficial effect is related to blood-brain barrier preservation.

DESIGN

Following controlled traumatic brain injury, hemorrhagic shock, various resuscitation and treatment strategies were evaluated for their association with blood-brain barrier integrity. Analysis of gene expression profiles was performed using Porcine Gene ST 1.1 microarray. Pathway analysis was completed using network analysis tools (Gene Ontology, Ingenuity Pathway Analysis, and Parametric Gene Set Enrichment Analysis).

SUBJECTS

Female Yorkshire swine were subjected to controlled traumatic brain injury and 2 hours of hemorrhagic shock (40% blood volume, mean arterial pressure 30-35 mmHg).

INTERVENTIONS

Subjects were resuscitated with 1) normal saline, 2) fresh frozen plasma, 3) hetastarch, 4) fresh frozen plasma + valproic acid, or 5) hetastarch + valproic acid (n = 5 per group). After 6 hours of observation, brains were harvested for evaluation.

MEASUREMENTS AND MAIN RESULTS

Immunofluoroscopic evaluation of the traumatic brain injury site revealed significantly increased expression of tight-junction associated proteins (zona occludin-1, claudin-5) following combination therapy (fresh frozen plasma + valproic acid and hetastarch + valproic acid). The extracellular matrix protein laminin was found to have significantly improved expression with combination therapies. Pathway analysis indicated that valproic acid significantly modulated pathways involved in endothelial barrier function and cell signaling.

CONCLUSIONS

Resuscitation with fresh frozen plasma results in improved expression of proteins essential for blood-brain barrier integrity. The addition of valproic acid provides significant improvement to these protein expression profiles. This is likely secondary to activation of key pathways related to endothelial functions.

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.

Early resuscitation with lyophilized plasma provides equal neuroprotection compared with fresh frozen plasma in a large animal survival model of traumatic brain injury and hemorrhagic shock

BACKGROUND

Combined traumatic brain injury (TBI) and hemorrhagic shock (HS) is highly lethal. In previous models of combined TBI + HS, we showed that early resuscitation with fresh frozen plasma (FFP) improves neurologic outcomes. Delivering FFP, however, in austere environments is difficult. Lyophilized plasma (LP) is a logistically superior alternative to FFP, but data are limited regarding its efficacy for treatment of TBI. We conducted this study to determine the safety and long-term outcomes of early treatment with LP in a large animal model of TBI + HS.

METHODS

Adult anesthetized swine underwent TBI and volume-controlled hemorrhage (40% blood volume) concurrently. After 2 hours of shock, animals were randomized (n = 5 per /group) to FFP or LP (1× shed blood) treatment. Serial blood gases were drawn, and thromboelastography was performed on citrated, kaolin-activated whole-blood samples. Five hours after treatment, packed red blood cells were administered, and animals recovered. A 32-point Neurologic Severity Score was assessed daily for 30 days (0 = normal, 32 = most severe injury). Cognitive functions were tested by training animals to retrieve food from color-coded boxes. Brain lesion size was measured on serial magnetic resonance imaging, and an autopsy was performed at 30 days.

RESULTS

The severity of shock and the degree of resuscitation were similar in both groups. Administration of FFP and LP was well tolerated with no differences in reversal of shock or thromboelastography parameters. Animals in both groups displayed the worst Neurologic Severity Score on postoperative Day 1 with rapid recovery and return to baseline within 7 days of injury. Lesion size on Day 3 in FFP-treated animals was 645 ± 85 versus 219 ± 20 mm in LP-treated animals (p < 0.05). There were no differences in cognitive functions or delayed treatment-related complications.

CONCLUSIONS

Early treatment with LP in TBI + HS is safe and provides neuroprotection that is comparable to FFP.

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.

Resuscitation with Pooled and Pathogen-Reduced Plasma Attenuates the Increase in Brain Water Content following Traumatic Brain Injury and Hemorrhagic Shock in Rats

Traumatic brain injury and hemorrhagic shock is associated with blood-brain barrier (BBB) breakdown and edema formation. Recent animal studies have shown that fresh frozen plasma (FFP) resuscitation reduces brain swelling and improves endothelial function compared to isotonic NaCl (NS). The aim of this study was to investigate whether pooled and pathogen-reduced plasma (OctaplasLG^® [OCTA]; Octapharma, Stockholm, Sweden) was comparable to FFP with regard to effects on brain water content, BBB permeability, and plasma biomarkers of endothelial glycocalyx shedding and cell damage. After fluid percussion brain injury, hemorrhage (20 mL/kg), and 90-min shock, 48 male Sprague-Dawley rats were randomized to resuscitation with OCTA, FFP, or NS (n = 16/group). Brain water content (wet/dry weight) and BBB permeability (transfer constant for ⁵¹Cr-EDTA) were measured at 24 h. Plasma osmolality, oncotic pressure, and biomarkers of systemic glycocalyx shedding (syndecan-1) and cell damage (histone-complexed DNA) were measured at 0 and 23 h. At 24 h, brain water content was 80.44 ± 0.39%, 80.82 ± 0.82%, and 81.15 ± 0.86% in the OCTA, FFP, and NS groups (lower in OCTA vs. NS; p = 0.026), with no difference in BBB permeability. Plasma osmolality and oncotic pressures were highest in FFP and OCTA resuscitated, and osmolality was further highest in OCTA versus FFP (p = 0.027). In addition, syndecan-1 was highest in FFP and OCTA resuscitated (p = 0.010). These results suggest that pooled solvent-detergent (SD)-treated plasma attenuates the post-traumatic increase in brain water content, and that this effect may, in part, be explained by a high crystalloid and colloid osmotic pressure in SD-treated plasma.

Platelets regulate vascular endothelial stability: assessing the storage lesion and donor variability of apheresis platelets

BACKGROUND

In current blood banking practices, platelets (PLTs) are stored in plasma at 22°C, with gentle agitation for up to 5 days. To date, the effects of storage and donor variability on PLT regulation of vascular integrity are not known.

STUDY DESIGN AND METHODS

In this study, we examined the donor variability of leukoreduced fresh (Day 1) or stored (Day 5) PLTs on vascular endothelial barrier function in vitro and in vivo. In vitro, PLT effects on endothelial cell (EC) monolayer permeability were assessed by analyzing transendothelial electrical resistances (TEER). PLT aggregation, a measure of hemostatic potential, was analyzed by impedance aggregometry. In vivo, PLTs were investigated in a vascular endothelial growth factor A (VEGF-A)-induced vascular permeability model in NSG mice, and PLT circulation was measured by flow cytometry.

RESULTS

Treatment of endothelial monolayers with fresh Day 1 PLTs resulted in an increase in EC barrier resistance and decreased permeability in a dose-dependent manner. Subsequent treatment of EC monolayers with Day 5 PLTs demonstrated diminished vasculoprotective effects. Donor variability was noted in all measures of PLT function. Day 1 PLT donors were more variable in their effects on TEER than Day 5 PLTs. In mice, while all PLTs regardless of storage time demonstrated significant protection against VEGF-A-induced vascular leakage, Day 5 PLTs exhibited reduced protection when compared to Day 1 PLTs. Day 1 PLTs demonstrated significant donor variability against VEGF-A-challenged vascular leakage in vivo. Systemic circulating levels of Day 1 PLTs were higher than those of Day 5 PLTs

CONCLUSIONS

In vitro and in vivo, Day 1 PLTs are protective in measures of vascular endothelial permeability. Donor variability is most prominent in Day 1 PLTs. A decrease in the protective effects is found with storage of the PLT units between Day 1 and Day 5 at 22°C, thereby suggesting that Day 5 PLTs are diminished in their ability to attenuate vascular endothelial permeability.

Fresh frozen plasma reduces edema in skeletal muscle following combined limb ischemia-reperfusion injury and hemorrhagic shock in rats

BACKGROUND

Exsanguination from extremity vascular injuries is the most common potentially survivable injury on the battlefield. Advances in treatment have dramatically improved survival, increasing the need to address associated morbidities including ischemia-reperfusion injury and extremity compartment syndrome. Despite advances, hemorrhagic shock (HS) requiring fluid resuscitation is common. Plasma-based resuscitation for the treatment of HS has been shown to reduce edema and injury in tissues other than muscle. The objective of this study was to determine if fresh frozen plasma (FFP) resuscitation offered protection in a rat model of combined HS and skeletal muscle ischemia-reperfusion injury.

METHODS

Anesthetized Sprague-Dawley rats underwent 37.5% arterial hemorrhage, producing HS, followed by 3 hours of tourniquet application. Animals were not resuscitated or resuscitated with either FFP (equal to the shed blood volume) or lactated Ringer's solution (three times shed volume) after 30 minutes of ischemia. They were euthanized 24 hours later, and their muscles were analyzed for edema (wet weight-dry weight). Routine histology was performed on muscle cross-sections stained with hematoxylin and eosin and graded using a semiquantitative grading system.

RESULTS

All animals developed HS; the mortality rate was 50% in no resuscitation rats. FFP reduced edema by 13% (p = 0.02) compared with lactated Ringer's solution. Pathology scores were not different between treatment groups.

CONCLUSION

FFP resuscitation reduces edema following muscle injury, decreasing the risk of developing extremity compartment syndrome.

Expression of aquaporin-4 and pathological characteristics of brain injury in a rat model of traumatic brain injury

Aquaporin 4 (AQP4) is a widely distributed membrane protein, which is found in glial cells, ependymocytes and capillary endothelial cells in the brain, and particularly in the choroid plexus. AQP4 is a key regulator of water metabolism, and changes in its expression following brain injury are associated with pathological changes in the damaged side of the brain; however, the effects of brain injury on AQP4 and injury‑induced pathological changes in the contralateral non‑damaged side of the brain remain to be fully elucidated. In the present study, male Sprague‑Dawley rats were subjected to traumatic brain injury (TBI) and changes in brain water content, the expression of AQP4 expression and pathological characteristics in the damaged and contralateral non‑damaged sides of the brain were examined. In the damaged side of the brain, vasogenic edema appeared first, followed by cellular edema. The aggravated cellular edema in the damaged side of the brain resulted in two periods of peak edema severity. Pathological changes in the contralateral non‑damaged side of the brain occurred later than those in the damaged side; cellular edema appeared first, followed by vasogenic edema, which was alleviated earlier than the cellular edema. AQP4 was downregulated during vasogenic edema, and upregulated during cellular edema. Taken together, these results suggested that the downregulation of AQP4 was a result of vasogenic edema and that the upregulation of AQP4 may have induced cellular edema.

Fresh frozen plasma and spray-dried plasma mitigate pulmonary vascular permeability and inflammation in hemorrhagic shock

BACKGROUND

In retrospective and prospective observational studies, fresh frozen plasma (FFP) has been associated with a survival benefit in massively transfused trauma patients. A dry plasma product, such as spray-dried plasma (SDP), offers logistical advantages over FFP. Recent studies on FFP have demonstrated that FFP modulates systemic vascular stability and inflammation. The effect of SDP on these measures has not been previously examined. This study compares SDP with FFP using in vitro assays of endothelial function and in vivo assays of lung injury using a mouse model of hemorrhagic shock (HS) and trauma.

METHODS

FFP, SDP, and lactated Ringer's (LR) solution were compared in vitro using assays of endothelial cell (EC) permeability, cytokine production and content, gene expression, as well as tight and adherens junction stability. All resuscitation products were also compared in a murine model of HS. Mean arterial pressures and physiologic measures were assessed. Pulmonary vascular permeability was measured using tagged dextran. Lung tissues were stained for CD68, VE-cadherin, and occludin.

RESULTS

Treatment of ECs with FFP and SDP, but not LR, preserved the integrity of EC monolayers in vitro and resulted in similar EC gene expression patterns and cytokine/growth factor production. FFP and SDP also reduced HS-induced pulmonary vascular permeability in vivo to the same extent. In mice with HS, mean arterial pressures and base excess were corrected by both FFP and SDP to levels observed in sham-treated mice. Treatment after HS with FFP and SDP but not LR solution reduce alveolar wall thickening, leukocyte infiltration, and the breakdown of EC junctions, as measured by staining for VE-cadherin, and occludin.

CONCLUSION

Both FFP and SDP similarly modulate pulmonary vascular integrity, permeability, and inflammation in vitro and in vivo in a murine model of HS and trauma.

Early resuscitation with fresh frozen plasma for traumatic brain injury combined with hemorrhagic shock improves neurologic recovery

BACKGROUND

We have shown that early administration of fresh frozen plasma (FFP) reduces the size of brain lesions 6 hours after injury in a large animal model of traumatic brain injury (TBI) and hemorrhagic shock (HS). To examine long-term outcomes, we hypothesized that early treatment with FFP would result in faster neurologic recovery and better long-term outcomes in a combined TBI and HS model.

STUDY DESIGN

Anesthetized Yorkshire swine underwent combined TBI and volume-controlled hemorrhage (40% blood volume). After 2 hours of shock, animals were randomized (n = 5/group) to normal saline (3× shed blood) or FFP (1× shed blood) treatment. A neurologic severity score was assessed for 30 days. Magnetic resonance imaging of the brain was performed at days 3, 10, and 24. Cognitive function was tested by training animals to retrieve food from color-coded boxes.

RESULTS

Neurologic impairment was lower and speed of recovery was considerably faster in the FFP-treated animals. There was a trend toward a smaller lesion size in FFP-treated animal at days 3 and 10, but this did not reach statistical significance. Both groups reached baseline performance on the cognitive testing; however, FFP-treated animals were able to participate, on average, 8 days earlier due to quicker recovery.

CONCLUSIONS

This is the first study to demonstrate the beneficial effects of FFP treatment in a long-term survival model of combined TBI and HS. Our data show that early treatment with FFP substantially attenuates the degree of neurologic impairment, improves the rate of recovery, and preserves the cognitive functions.

Resuscitation speed affects brain injury in a large animal model of traumatic brain injury and shock

Background

Optimal fluid resuscitation strategy following combined traumatic brain injury (TBI) and hemorrhagic shock (HS) remain controversial and the effect of resuscitation infusion speed on outcome is not well known. We have previously reported that bolus infusion of fresh frozen plasma (FFP) protects the brain compared with bolus infusion of 0.9% normal saline (NS). We now hypothesize reducing resuscitation infusion speed through a stepwise infusion speed increment protocol using either FFP or NS would provide neuroprotection compared with a high speed resuscitation protocol.

Methods

23 Yorkshire swine underwent a protocol of computer controlled TBI and 40% hemorrhage. Animals were left in shock (mean arterial pressure of 35 mmHg) for two hours prior to resuscitation with bolus FFP (n = 5, 50 ml/min) or stepwise infusion speed increment FFP (n = 6), bolus NS (n = 5, 165 ml/min) or stepwise infusion speed increment NS (n = 7). Hemodynamic variables over a 6-hour observation phase were recorded. Following euthanasia, brains were harvested and lesion size as well as brain swelling was measured.

Results

Bolus FFP resuscitation resulted in greater brain swelling (22.36 ± 1.03% vs. 15.58 ± 2.52%, p = 0.04), but similar lesion size compared with stepwise resuscitation. This was associated with a lower cardiac output (CO: 4.81 ± 1.50 l/min vs. 5.45 ± 1.14 l/min, p = 0.03). In the NS groups, bolus infusion resulted in both increased brain swelling (37.24 ± 1.63% vs. 26.74 ± 1.33%, p = 0.05) as well as lesion size (3285.44 ± 130.81 mm³ vs. 2509.41 ± 297.44 mm³, p = 0.04). This was also associated with decreased cardiac output (NS: 4.37 ± 0.12 l/min vs. 6.35 ± 0.10 l/min, p < 0.01).

Conclusions

In this clinically relevant model of combined TBI and HS, stepwise resuscitation protected the brain compared with bolus resuscitation.