Valproic acid decreases brain lesion size and improves neurologic recovery in swine subjected to traumatic brain injury, hemorrhagic shock, and polytrauma

Association of severe postpartum hemorrhage and development of psychological disorders: Results from the prospective and multicentre HELP MOM study

OBJECTIVE

Post-partum hemorrhage (PPH) is the leading preventable cause of worldwide maternal morbidity and mortality. Risk factors for psychological disorders following PPH are currently unknown. HELP-MOM study aimed to determine the incidence and identify risk factors for psychological disorders following PPH.

METHODS

HELP-MOM study was a prospective, observational, national, and multicentre study including patients who experienced severe PPH requiring sulprostone. The primary endpoint was the occurrence of psychological disorders (anxiety and/or post-traumatic disorder and/or depression) following PPH, assessed at 1, 3, and 6 months after delivery using HADS, IES-R, and EPDS scales.

RESULTS

Between November 2014 and November 2016, 332 patients experienced a severe PPH and 236 (72%) answered self-questionnaires at 1, 3, and 6 months. A total of 161 (68%) patients declared a psychological disorder following severe PPH (146 (90.1%) were screened positive for anxiety, 96 (58.9%) were screened positive for post-traumatic stress disorder, and 94 (57.7%) were screened positive for post-partum depression). In multivariable analysis, the use of intra-uterine tamponnement balloon was associated with a lower risk to be screened positive for psychological disorder after severe PPH (OR = 0.33 [IC95% 0.15-0.69], p = 0.004, and after propensity score matching (OR=0.34 [IC95% 0.12-0.94], p = 0.04)). Low hemoglobin values during severe PPH management were associated with a higher risk of being screened positive for psychological disorders. Finally, we did not find differences in desire or pregnancy between patients without or with psychological disorders occurring in the year after severe PPH.

DISCUSSION

Severe PPH was associated with significant psychosocial morbidity including anxiety, post-traumatic disorder, and depression. This should engage a psychological follow-up. Large cohorts are urgently needed to confirm our results.

REGISTRATION

ClinicalTrials.gov under number NCT02118038.

Prolonging the therapeutic window for valproic acid treatment in a swine model of traumatic brain injury and hemorrhagic shock

BACKGROUND

It has previously been shown that administration of valproic acid (VPA) can improve outcomes if given within an hour following traumatic brain injury (TBI). This short therapeutic window (TW) limits its use in real-life situations. Based upon its pharmacokinetic data, we hypothesized that TW can be extended to 3 hours if a second dose of VPA is given 8 hours after the initial dose.

METHOD

Yorkshire swine (40-45 kg; n = 10) were subjected to TBI (controlled cortical impact) and 40% blood volume hemorrhage. After 2 hours of shock, they were randomized to either (1) normal saline resuscitation (control) or (2) normal saline-VPA (150 mg/kg × two doses). First dose of VPA was started 3 hours after the TBI, with a second dose 8 hours after the first dose. Neurologic severity scores (range, 0-36) were assessed daily for 14 days, and brain lesion size was measured via magnetic resonance imaging on postinjury day 3.

RESULTS

Hemodynamic and laboratory parameters of shock were similar in both groups. Valproic acid-treated animals had significantly less neurologic impairment on days 2 (16.3 ± 2.0 vs. 7.3 ± 2.8) and 3 (10.9 ± 3.6 vs. 2.8 ± 1.1) postinjury and returned to baseline levels 54% faster. Magnetic resonance imaging showed no differences in brain lesion size on day 3. Pharmacokinetic data confirmed neuroprotective levels of VPA in the circulation.

CONCLUSION

This is the first study to demonstrate that VPA can be neuroprotective even when given 3 hours after TBI. This expanded TW has significant implications for the design of the clinical trial.

Therapeutic Administration of Oxcarbazepine Saves Cerebellar Purkinje Cells from Ischemia and Reperfusion Injury Induced by Cardiac Arrest through Attenuation of Oxidative Stress

Research reports using animal models of ischemic insults have demonstrated that oxcarbazepine (a carbamazepine analog: one of the anticonvulsant compounds) extends neuroprotective effects against cerebral or forebrain injury induced by ischemia and reperfusion. However, research on protective effects against ischemia and reperfusion cerebellar injury induced by cardiac arrest (CA) and the return of spontaneous circulation has been poor. Rats were assigned to four groups as follows: (Groups 1 and 2) sham asphyxial CA and vehicle- or oxcarbazepine-treated, and (Groups 3 and 4) CA and vehicle- or oxcarbazepine-treated. Vehicle (0.3% dimethyl sulfoxide/saline) or oxcarbazepine (200 mg/kg) was administered intravenously ten minutes after the return of spontaneous circulation. In this study, CA was induced by asphyxia using vecuronium bromide (2 mg/kg). We conducted immunohistochemistry for calbindin D-28kDa and Fluoro-Jade B histofluorescence to examine Purkinje cell death induced by CA. In addition, immunohistochemistry for 4-hydroxy-2-nonenal (4HNE) was carried out to investigate CA-induced oxidative stress, and immunohistochemistry for Cu, Zn-superoxide dismutase (SOD1) and Mn-superoxide dismutase (SOD2) was performed to examine changes in endogenous antioxidant enzymes. Oxcarbazepine treatment after CA significantly increased the survival rate and improved neurological deficit when compared with vehicle-treated rats with CA (survival rates ≥ 63.6 versus 6.5%), showing that oxcarbazepine treatment dramatically protected cerebellar Purkinje cells from ischemia and reperfusion injury induced by CA. The salvation of the Purkinje cells from ischemic injury by oxcarbazepine treatment paralleled a dramatic reduction in 4HNE (an end-product of lipid peroxidation) and increased or maintained the endogenous antioxidant enzymes (SOD1 and SOD2). In brief, this study shows that therapeutic treatment with oxcarbazepine after CA apparently saved cerebellar neurons (Purkinje cells) from CA-induced neuronal death by attenuating oxidative stress and suggests that oxcarbazepine can be utilized as a therapeutic medicine for ischemia and reperfusion brain (cerebellar) injury induced by CA.

IL-18BP Alleviates Anxiety-Like Behavior Induced by Traumatic Stress via Inhibition of the IL-18R-NLRP3 Signaling Pathway in a Mouse Model of Hemorrhagic Shock and Resuscitation

Psychological distress and posttraumatic stress, including anxiety, severely influence life quality. Previously, we reported that interleukin-18 (IL-18) was involved in pyroptosis-induced emotional changes in a rodent model of hemorrhagic shock and resuscitation (HSR). Here, we aimed to continue our investigation on the role of IL-18 binding protein (IL-18BP), which exhibits excellent anti-inflammatory effects as an IL-18 negative regulator. Mice were administered with an intraperitoneal injection of IL-18BP after HSR exposure and anxiety-like behavior was examined using the open-field test and elevated plus maze test. Moreover, the following variables post-HSR were measured: (1) the activation of astrocytes; (2) pyroptosis-associated factors including cleaved caspase-1, GSDMD, IL-18; (3) the roles of IL-18 receptor (IL-18R)-NOD-like receptor pyrin domain-containing-3 (NLRP3) signal with the application of the NLRP3 specific agonist or astrocyte-specific NLRP3 knockout mice. IL-18BP administration remarkably alleviated HSR-induced anxiety-like behavior, astrocytic activation, and increases in pyroptosis-associated factors, while NLRP3 agonist nigericin partially reversed IL-18BP-induced neuroprotective effects. Astrocyte-specific NLRP3 knockout mice exhibited relatively less anxiety-like behavior. Similarly, IL-18BP exhibited an anti-pyroptosis effect in astrocytes in an in vitro model of low oxygen-glucose deprivation. These findings offer unique perspectives on HSR-induced posttraumatic stress and indicate that inhibition of IL-18R-NLRP3 signal via IL-18BP can attenuate astrocytic activation and pyroptosis, broadening the therapeutic landscape for patients with psychological distress and posttraumatic stress.

Brain Histology and Immunohistochemistry After Resuscitation From Hemorrhagic Shock in Swine With Pre-Existing Atherosclerosis and Sodium Thiosulfate (Na2S2O3) Treatment

Background

The hydrogen sulfide (H₂S) and the oxytocin/oxytocin receptor (OT/OTR) systems interact in the central nervous and cardiovascular system. As a consequence of osmotic balance stress, H₂S stimulates OT release from the paraventricular nuclei (PVN) in the hypothalamic regulation of blood volume and pressure. Hemorrhagic shock (HS) represents one of the most pronounced acute changes in blood volume, which, moreover, may cause at least transient brain tissue hypoxia. Atherosclerosis is associated with reduced vascular expression of the main endogenous H₂S producing enzyme cystathionine-γ-lyase (CSE), and, hence, exogenous H₂S administration could be beneficial in these patients, in particular after HS. However, so far cerebral effects of systemic H₂S administration are poorly understood. Having previously shown lung-protective effects of therapeutic Na₂S₂O₃ administration in a clinically relevant, long-term, porcine model of HS and resuscitation we evaluated if these protective effects were extended to the brain.

Methods

In this study, available unanalyzed paraffin embedded brain sections (Na₂S₂O₃N = 8 or vehicle N = 5) of our recently published HS study were analyzed via neuro-histopathology and immunohistochemistry for the endogenous H₂S producing enzymes, OT, OTR, and markers for brain injury and oxidative stress (glial fibrillary acidic protein (GFAP) and nitrotyrosine).

Results

Neuro-histopathological analysis revealed uninjured brain tissue with minor white matter edema. Protein quantification in the hypothalamic PVN showed no significant inter-group differences between vehicle or Na₂S₂O₃ treatment.

Conclusions

The endogenous H₂S enzymes, OT/OTR co-localized in magnocellular neurons in the hypothalamus, which may reflect their interaction in response to HS-induced hypovolemia. The preserved blood brain barrier (BBB) may have resulted in impermeability for Na₂S₂O₃ and no inter-group differences in the PVN. Nonetheless, our results do not preclude that Na₂S₂O₃ could have a therapeutic benefit in the brain in an injury that disrupts the BBB, e.g., traumatic brain injury (TBI) or acute subdural hematoma (ASDH).

Resuscitation fluids as drugs: targeting the endothelial glycocalyx

ABSTRACT

Fluid resuscitation is an essential intervention in critically ill patients, and its ultimate goal is to restore tissue perfusion. Critical illnesses are often accompanied by glycocalyx degradation caused by inflammatory reactions, hypoperfusion, shock, and so forth, leading to disturbed microcirculatory perfusion and organ dysfunction. Therefore, maintaining or even restoring the glycocalyx integrity may be of high priority in the therapeutic strategy. Like drugs, however, different resuscitation fluids may have beneficial or harmful effects on the integrity of the glycocalyx. The purpose of this article is to review the effects of different resuscitation fluids on the glycocalyx. Many animal studies have shown that normal saline might be associated with glycocalyx degradation, but clinical studies have not confirmed this finding. Hydroxyethyl starch (HES), rather than other synthetic colloids, may restore the glycocalyx. However, the use of HES also leads to serious adverse events such as acute kidney injury and bleeding tendencies. Some studies have suggested that albumin may restore the glycocalyx, whereas others have suggested that balanced crystalloids might aggravate glycocalyx degradation. Notably, most studies did not correct the effects of the infusion rate or fluid volume; therefore, the results of using balanced crystalloids remain unclear. Moreover, mainly animal studies have suggested that plasma may protect and restore glycocalyx integrity, and this still requires confirmation by high-quality clinical studies.

A single dose of valproic acid improves neurologic recovery and decreases brain lesion size in swine subjected to an isolated traumatic brain injury

BACKGROUND

We lack specific treatments for traumatic brain injury (TBI), which remains the leading cause of trauma-related morbidity and mortality. Treatment with valproic acid (VPA) improves outcomes in models of severe TBI with concurrent hemorrhage. However, it is unknown if VPA will have similar benefits after isolated nonlethal TBI, which is the more common clinical scenario. The goal of this study was to evaluate the effect of VPA treatment in a preclinical isolated TBI swine model on neurologic outcomes and brain lesion size and to perform detailed pharmacokinetic analyses for a future clinical trial.

METHODS

Yorkshire swine (n = 10; 5/cohort) were subjected to TBI (8-mm controlled cortical impact). An hour later, we randomized them to receive VPA (150 mg/kg) or saline placebo (control). Neuroseverity scores were assessed daily (0 [normal] to 36 [comatose]), brain lesion size was measured on postinjury 3, and serial blood samples were collected for pharmacokinetic studies.

RESULTS

Physiologic parameters and laboratory values were similar in both groups. Valproic acid-treated animals demonstrated significantly better neuroseverity scores on postinjury 1 (control, 9.2 ± 4.4; VPA, 0 ± 0; p = 0.001). Valproic acid-treated animals had significantly smaller brain lesion sizes (mean volume in microliter: control, 3,130 ± 2,166; VPA, 764 ± 208; p = 0.02). Pharmacokinetic data confirmed adequate plasma and tissue levels of VPA.

CONCLUSION

In this clinically relevant model of isolated TBI, a single dose of VPA attenuates neurological impairment and decreases brain lesion size.

Sustained Dysbiosis and Decreased Fecal Short-Chain Fatty Acids after Traumatic Brain Injury and Impact on Neurologic Outcome

Traumatic brain injury (TBI) alters microbial populations present in the gut, which may impact healing and tissue recovery. However, the duration and impact of these changes on outcome from TBI are unknown. Short-chain fatty acids (SCFAs), produced by bacterial fermentation of dietary fiber, are important signaling molecules in the microbiota gut-brain axis. We hypothesized that TBI would lead to a sustained reduction in SCFA producing bacteria, fecal SCFAs concentration, and administration of soluble SCFAs would improve functional outcome after TBI. Adult mice (n = 10) had the controlled cortical impact (CCI) model of TBI performed (6 m/sec, 2-mm depth, 50-msec dwell). Stool samples were collected serially until 28 days after CCI and analyzed for SCFA concentration by high-performance liquid chromatography-mass spectrometry/mass spectrometry and microbiome analyzed by 16S gene sequencing. In a separate experiment, mice (n = 10/group) were randomized 2 weeks before CCI to standard drinking water or water supplemented with the SCFAs acetate (67.5 mM), propionate (25.9 mM), and butyrate (40 mM). Morris water maze performance was assessed on post-injury Days 14-19. Alpha diversity remained stable until 72 h, at which point a decline in diversity was observed without recovery out to 28 days. The taxonomic composition of post-TBI fecal samples demonstrated depletion of bacteria from Lachnospiraceae, Ruminococcaceae, and Bacteroidaceae families, and enrichment of bacteria from the Verrucomicrobiaceae family. Analysis from paired fecal samples revealed a reduction in total SCFAs at 24 h and 28 days after TBI. Acetate, the most abundant SCFA detected in the fecal samples, was reduced at 7 days and 28 days after TBI. SCFA administration improved spatial learning after TBI versus standard drinking water. In conclusion, TBI is associated with reduced richness and diversity of commensal microbiota in the gut and a reduction in SCFAs detected in stool. Supplementation of soluble SCFAs improves spatial learning after TBI.

Brain proteomic changes by histone deacetylase inhibition after traumatic brain injury

Background

Traumatic brain injury (TBI) is a leading cause of morbidity and mortality. There are currently no cytoprotective treatments for TBI. There is growing evidence that the histone deacetylase inhibitor valproic acid (VPA) may be beneficial in the treatment of TBI associated with hemorrhagic shock and in isolation. We sought to further evaluate the mechanistic underpinnings of this demonstrated efficacy via proteomic analysis of injured brain tissue.

Methods

Swine were subjected to TBI via controlled cortical impact, randomized to treatment with VPA or control and observed for 6 hours. The brains of the pigs were then sectioned, and tissue was prepared and analyzed for proteomic data, including gene ontology (GO), gene-set enrichment analysis and enrichment mapping, and network mapping.

Results

Proteomic analysis demonstrated differential expression of hundreds of proteins in injured brain tissue after treatment with VPA. GO analysis and network analyses revealed groups of proteins and processes that are known to modulate injury response after TBI and impact cell fate. Processes affected included protein targeting and transport, cation and G-protein signaling, metabolic response, neurotransmitter response and immune function.

Discussion

This proteomic analysis provides initial mechanistic insight into the observed rescue of injured brain tissue after VPA administration in isolated TBI.

Level of evidence

Not applicable (animal study).

Validation of intraosseous delivery of valproic acid in a swine model of polytrauma

Background

Intraosseous (IO) drug delivery may be necessary in emergency situations when intravenous access is unattainable. Valproic acid (VPA) is a histone deacetylase inhibitor that has previously been shown to improve survival in preclinical models of lethal polytrauma. In this study, we sought to compare serum levels of intravenously and IO-delivered VPA, and to analyze the effect of IO-delivered VPA.

Methods

Swine were subjected to 40% blood volume hemorrhage, brain injury, femur fracture, rectus crush injury and liver laceration. After 1 hour of shock, animals were randomized (n=3/group) to receive normal saline resuscitation (control), normal saline+intravenous VPA 150 mg/kg (intravenous group) or normal saline +IO VPA 150 mg/kg (IO group). Serum levels of VPA were assessed between groups, and proteomics analyses were performed on IO and control groups on heart, lung and liver samples.

Results

Intravenous and IO serum VPA levels were similar at 1, 3, 5 and 7 hours after starting the infusion (p>0.05). IO-delivered VPA induced significant proteomics changes in the heart, lung and liver, which were most pronounced in the lung. Biologic processes affected included inflammation, metabolism and transcriptional & translational machinery. The control group had 0% survival, and the intravenous and IO group both had 100% survival to the end of the experiment (p<0.05).

Discussion

IO-delivered VPA is noninferior to intravenous administration and is a viable option in emergent situations when intravenous access is unattainable.

Level of evidence

Not applicable (animal study).

Valproic acid treatment rescues injured tissues after traumatic brain injury

BACKGROUND

No agents that are specifically neuroprotective are currently approved to emergently treat patients with traumatic brain injury (TBI). The histone deacetylase inhibitor, high-dose valproic acid (VPA) has been shown to have cytoprotective potential in models of combined TBI and hemorrhagic shock, but it has not been tested in an isolated TBI model. We hypothesized that VPA, administered after isolated TBI, will penetrate the injured brain, attenuate the lesion size, and activate prosurvival pathways.

METHODS

Yorkshire swine were subjected to severe TBI by cortical impact. One hour later, animals were randomized to VPA treatment (150 mg/kg delivered intravenously for 1 hour; n = 4) or control (saline vehicle; n = 4) groups. Seven hours after injury, animals were sacrificed, and brain lesion size was measured. Mass spectrometry imaging was used to visualize and quantitate brain tissue distribution of VPA. Sequential serum samples were assayed for key biomarkers and subjected to proteomic and pathway analysis.

RESULTS

Brain lesion size was 50% smaller (p = 0.01) in the VPA-treated animals (3,837 ± 948 mm) compared with the controls (1,900 ± 614 mm). Endothelial regions had eightfold higher VPA concentrations than perivascular regions by mass spectrometry imaging, and it readily penetrated the injured brain tissues. Serum glial fibrillary acid protein was significantly lower in the VPA-treated compared with the control animals (p < 0.05). More than 500 proteins were differentially expressed in the brain, and pathway analysis revealed that VPA affected critical modulators of TBI response including calcium signaling pathways, mitochondria metabolism, and biosynthetic machinery.

CONCLUSION

Valproic acid penetrates injured brain tissues and exerts neuroprotective and prosurvival effects that resulted in a significant reduction in brain lesion size after isolated TBI. Levels of serum biomarkers reflect these changes, which could be useful for monitoring the response of TBI patients during clinical studies.

Administration of valproic acid in clinically approved dose improves neurologic recovery and decreases brain lesion size in swine subjected to hemorrhagic shock and traumatic brain injury

BACKGROUND

Traumatic brain injury (TBI) and hemorrhage remain the leading causes of death after trauma. We have previously shown that a dose of valproic acid (VPA) at (150 mg/kg) can decrease brain lesion size and hasten neurologic recovery. The current Food and Drug Administration-approved dose of VPA is 60 mg/kg. We evaluate neurologic outcomes and brain lesion size of a single dose of VPA at a level currently within Food and Drug Administration-approved dose in swine subjected to TBI and hemorrhagic shock.

METHODS

Swine (n = 5/group) were subjected to TBI and 40% blood volume hemorrhage. Animals remained in shock for 2 hours before randomization to normal saline (NS) resuscitation alone (control), NS-VPA 150 mg/kg (VPA 150), or NS-VPA 50 mg/kg (VPA 50). Neurologic severity scores (range, 0-32) were assessed daily for 14 days, and brain lesion size was measured via magnetic resonance imaging on postinjury day (PID) 3.

RESULTS

Shock severity and laboratory values were similar in all groups. Valproic acid-treated animals demonstrated significantly less neurologic impairment on PID 1 and returned to baseline faster (PID 1 mean neurologic severity score, control = 22 ± 3 vs. VPA 150 mg/kg = 8 ± 7 or VPA 50 mg/kg = 6 ± 6; p = 0.02 and 0.003). Valproic acid-treated animals had significantly smaller brain lesion sizes (mean volume in mm3, control = 1,268.0 ± 241.2 vs. VPA 150 mg/kg = 620.4 ± 328.0 or VPA 50 mg/kg = 438.6 ± 234.8; p = 0.007 and 0.001).

CONCLUSION

In swine subjected to TBI and hemorrhagic shock, VPA treatment, in a dose that is approved for clinical use, decreases brain lesion size and reduces neurologic impairment compared with resuscitation alone.

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.

Targeting Uric Acid Prevents Brain Injury and Anxiety in a Rat Model of Hemorrhagic Shock

ABSTRACT

Secondary brain injury following hemorrhagic shock (HS) is a frequent complication in patients, even in the absence of direct brain trauma, leading to behavioral changes and more specifically anxiety and depression. Despite preclinical studies showing inflammation and apoptosis in the brain after HS, none have addressed the impact of circulating mediators. Our group demonstrated an increased uric acid (UA) circulation in rats following HS. Since UA is implicated in endothelial dysfunction and inflammatory response, we hypothesized UA could alter the blood-brain barrier (BBB) and impact the brain. Male Wistar rats were randomly assigned to: SHAM, HS (hemorrhagic shock) and HS + U (hemorrhagic shock + 1.5 mg/kg of uricase). The uricase intervention, specifically targeting UA, was administered during fluid resuscitation. It prevented BBB dysfunction (fluorescein sodium salt permeability and expression of intercellular adhesion molecule-1) following HS. As for neuroinflammation, all of the results obtained (MPO activity; Iba1 and GFAP expression) showed a significant increase after HS, also prevented by the uricase. The same pattern was observed after quantification of apoptosis (caspase-3 activity and TUNEL) and neurodegeneration (Fluoro-Jade). Finally, the forced swim, elevated plus maze, and social interaction tests detected anxiety-like behavior after HS, which was blunted in rats treated with the uricase. In conclusion, we have identified UA as a new circulatory inflammatory mediator, responsible for brain alterations and anxious behavior after HS in a murine model. The ability to target UA holds the potential of an adjunctive therapeutic solution to reduce brain dysfunction related to hemorrhagic shock in human.

Targeting Endothelial Dysfunction in Acute Critical Illness to Reduce Organ Failure

During hyperinflammatory conditions that can occur in acute critical illness, such as shock or hypoperfusion, inflammatory mediators activate the endothelium, fueling a proinflammatory host-response as well as procoagulant processes. These changes result in shedding of the glycocalyx, endothelial hyperpermeability, edema formation, and lead to disturbed microcirculatory perfusion and organ failure. Different fluid strategies that are used in shock may have differential effects on endothelial integrity. Collectively, low protein content fluids seem to have negative effects on the endothelial glycocalyx, aggravating endothelial hyperpermeability, whereas fluids containing albumin or plasma proteins may be superior to normal saline in protecting the glycocalyx and endothelial barrier function. Targeting the endothelium may be a therapeutic strategy to limit organ failure, which hitherto has not received much attention. Treatment targets aimed at restoring the endothelium should focus on maintaining glycocalyx function and/or targeting coagulation pathways or specific endothelial receptors. Potential treatments could be supplementing glycocalyx constituents or inhibiting glycocalyx breakdown. In this review, we summarize mechanisms of endothelial dysfunction during acute critical illness, such as the systemic inflammatory response, shedding of the glycocalyx, endothelial activation, and activation of coagulation. In addition, this review focuses on the effects of different fluid strategies on endothelial permeability. Also, potential mechanisms for treatment options to reduce endothelial hyperpermeability with ensuing organ failure are evaluated. Future research is needed to elucidate these pathways and to translate these data to the first human safety and feasibility trials.

Early single-dose exosome treatment improves neurologic outcomes in a 7-day swine model of traumatic brain injury and hemorrhagic shock

BACKGROUND

Early single-dose treatment with human mesenchymal stem cell-derived exosomes promotes neuroprotection and promotes blood-brain barrier integrity in models of traumatic brain injury (TBI) and hemorrhagic shock (HS) in swine. The impact of an early single dose of exosomes on late survival (7 days), however, remains unknown. We sought to evaluate the impact of early single-dose exosome treatment on neurologic outcomes, brain lesion size, inflammatory cytokines, apoptotic markers, and mediators of neural plasticity in a 7-day survival model.

METHODS

Yorkshire swine were subjected to a severe TBI (8-mm cortical impact) and HS (40% estimated total blood volume). After 1 hour of shock, animals were randomized (n = 4/cohort) to receive either lactated Ringer's (5 mL) or lactated Ringer's with exosomes (1 × 10 exosome particles). After an additional hour of shock, animals were resuscitated with normal saline. Daily neurologic severity scores were compared. At 7 days following injury, lesion size, inflammatory markers, and mediators of inflammation (NF-κB), apoptosis (BAX), and neural plasticity (brain-derived neurotrophic factor) in brain tissue were compared between groups.

RESULTS

Exosome-treated animals had significantly lower neurologic severity scores (first 4 days; p < 0.05) and faster neurologic recovery. At 7 days, exosome-treated animals had significantly smaller (p < 0.05) brain lesion sizes. Exosome-treated animals also had significantly lower levels of inflammatory markers (interleukin [IL]-1, IL-6, IL-8, and IL-18) and higher granulocyte-macrophage colony-stimulating factor levels compared with the control animals, indicating specific impacts on various cytokines. The BAX and NF-κB levels were significantly lower (p < 0.05) in exosome-treated animals, while brain-derived neurotrophic factor levels were significantly higher (p < 0.05) in the exosome-treated animals.

CONCLUSION

In a large animal model of TBI and HS, early single-dose exosome treatment attenuates neurologic injury, decreases brain lesion size, inhibits inflammation and apoptosis, and promotes neural plasticity over a 7-day period.

Class IIa HDAC inhibitor TMP195 alleviates lipopolysaccharide-induced acute kidney injury

Sepsis-associated acute kidney injury (SA-AKI) is associated with high mortality rates, but clinicians lack effective treatments except supportive care or renal replacement therapies. Recently, histone deacetylase (HDAC) inhibitors have been recognized as potential treatments for acute kidney injury and sepsis in animal models; however, the adverse effect generated by the use of pan inhibitors of HDACs may limit their application in people. In the present study, we explored the possible renoprotective effect of a selective class IIa HDAC inhibitor, TMP195, in a murine model of SA-AKI induced by lipopolysaccharide (LPS). Administration of TMP195 significantly reduced increased serum creatinine and blood urea nitrogen levels and renal damage induced by LPS; this was coincident with reduced expression of HDAC4, a major isoform of class IIa HDACs, and elevated histone H3 acetylation. TMP195 treatment following LPS exposure also reduced renal tubular cell apoptosis and attenuated renal expression of neutrophil gelatinase-associated lipocalin and kidney injury molecule-1, two biomarkers of tubular injury. Moreover, LPS exposure resulted in increased expression of BAX and cleaved caspase-3 and decreased expression of Bcl-2 and bone morphogenetic protein-7 in vivo and in vitro; TMP195 treatment reversed these responses. Finally, TMP195 inhibited LPS-induced upregulation of multiple proinflammatory cytokines/chemokines, including intercellular adhesion molecule-1, monocyte chemoattractant protein-1, tumor necrosis factor-α, and interleukin-1β, and accumulation of inflammatory cells in the injured kidney. Collectively, these data indicate that TMP195 has a powerful renoprotective effect in SA-AKI by mitigating renal tubular cell apoptosis and inflammation and suggest that targeting class IIa HDACs might be a novel therapeutic strategy for the treatment of SA-AKI that avoids the unintended adverse effects of a pan-HDAC inhibitor.

Diffusion Tensor Imaging-Based Studies at the Group-Level Applied to Animal Models of Neurodegenerative Diseases

The understanding of human and non-human microstructural brain alterations in the course of neurodegenerative diseases has substantially improved by the non-invasive magnetic resonance imaging (MRI) technique of diffusion tensor imaging (DTI). Animal models (including disease or knockout models) allow for a variety of experimental manipulations, which are not applicable to humans. Thus, the DTI approach provides a promising tool for cross-species cross-sectional and longitudinal investigations of the neurobiological targets and mechanisms of neurodegeneration. This overview with a systematic review focuses on the principles of DTI analysis as used in studies at the group level in living preclinical models of neurodegeneration. The translational aspect from in-vivo animal models toward (clinical) applications in humans is covered as well as the DTI-based research of the non-human brains' microstructure, the methodological aspects in data processing and analysis, and data interpretation at different abstraction levels. The aim of integrating DTI in multiparametric or multimodal imaging protocols will allow the interrogation of DTI data in terms of directional flow of information and may identify the microstructural underpinnings of neurodegeneration-related patterns.

CORM-3 improves emotional changes induced by hemorrhagic shock via the inhibition of pyroptosis in the amygdala

Hemorrhagic shock and resuscitation (HSR) may lead to long-term neurological dysfunction, such as depression and anxiety. Carbon monoxide (CO) has emerged as an excellent neuroprotective agent against caspase-1-associated pyroptosis, following HSR. We evaluated the effects and determined the mechanism through which CO protects against emotional changes in a model of HSR, in rats. We subjected rats to treatments with an exogenous, CO-releasing compound (CORM-3, 4 mg/kg), in vivo, after HSR. We measured sucrose preference and performed tail suspension and open field tests 7 days after HSR, assessed brain magnetic resonance imaging 12 h after HSR and evaluated pyroptosis, and neuronal and astrocyte death in the amygdala 12 h post-HSR. We also measured changes in behavior and pathology, following an injection of recombinant murine interleukin (IL)-18 into the amygdala. HSR-treated rats displayed increased depression-like and anxiety-like behaviors, increased amygdalar injury, as indicated by T2-weighted magnetic resonance imaging (MRI) and cerebral blood flow with arterial spin labeling (CBF_ASL), associated with both neuronal and astrocytic death and pyroptosis, and upregulated IL-18 expression was observed in astrocytes. CORM-3 administration after resuscitation, via a femoral vein injection, provided neuroprotection against HSR, and this neuroprotective effect could be partially reversed by the injection of recombinant murine IL-18 into the amygdala. Therefore, CORM-3 alleviated HSR-induced neuronal pyroptosis and emotional changes, through the downregulation of IL-18 in astrocytes.

Histone Deacetylase Inhibitors: A Novel Strategy in Trauma and Sepsis

Trauma remains a leading cause of morbidity and mortality among all age groups in the United States. Hemorrhagic shock and traumatic brain injury (TBI) are major causes of preventable death in trauma. Initial treatment involves fluid resuscitation to improve the intravascular volume. Although crystalloids may provide volume expansion, they do not have any pro-survival properties. Furthermore, aggressive fluid resuscitation can provoke a severe inflammatory response and worsen clinical outcomes. Due to logistical constraints, however, definitive resuscitation with blood products is often not feasible in the prehospital setting-highlighting the importance of adjunctive therapies. In recent years, histone deacetylase inhibitors (HDACis) have shown promise as pharmacologic agents for use in both trauma and sepsis. In this review, we discuss the role of histone deacetylases (HDACs) and pharmacologic agents that inhibit them (HDACis). We also highlight the therapeutic effects and mechanisms of action of HDACis in hemorrhagic shock, TBI, polytrauma, and sepsis. With further investigation and translation, HDACis have the potential to be a high-impact adjunctive therapy to traditional resuscitation.

Dose optimization of early high-dose valproic acid for neuroprotection in a swine cardiac arrest model

Aim

High-dose valproic acid (VPA) improves the survival and neurologic outcomes after asphyxial cardiac arrest (CA) in rats. We characterized the pharmacokinetics, pharmacodynamics, and safety of high-dose VPA in a swine CA model to advance clinical translation.

Methods

After 8 ​min of untreated ventricular fibrillation CA, 20 male Yorkshire swine were resuscitated until return of spontaneous circulation (ROSC). They were block randomized to receive placebo, 75 ​mg/kg, 150 ​mg/kg, or 300 ​mg/kg VPA as 90-min intravenous infusion (n ​= ​5/group) beginning at ROSC. Animals were monitored for 2 additional hours then euthanized. Experimental operators were blinded to treatments.

Results

The mean(SD) total CA duration was 14.8(1.2) minutes. 300 ​mg/kg VPA animals required more adrenaline to maintain mean arterial pressure ≥80 ​mmHg and had worse lactic acidosis. There was a strong linear correlation between plasma free VPA C_max and brain total VPA (r² ​= ​0.9494; p ​< ​0.0001). VPA induced dose-dependent increases in pan- and site-specific histone H3 and H4 acetylation in the brain. Plasma free VPA C_max is a better predictor than peripheral blood mononuclear cell histone acetylation for brain H3 and H4 acetylation (r² ​= ​0.7189 for H3K27ac, r² ​= ​0.7189 for pan-H3ac, and r² ​= ​0.7554 for pan-H4ac; p ​< ​0.0001).

Conclusions

Up to 150 ​mg/kg VPA can be safely tolerated as 90-min intravenous infusion in a swine CA model. High-dose VPA induced dose-dependent increases in brain histone H3 and H4 acetylation, which can be predicted by plasma free VPA C_max as the pharmacodynamics biomarker for VPA target engagement after CA.

Dose optimization of valproic acid in a lethal model of traumatic brain injury, hemorrhage, and multiple trauma in swine

BACKGROUND

Trauma is a leading cause of death, and traumatic brain injury is one of the hallmark injuries of current military conflicts. Valproic acid (VPA) administration in high doses (300-400 mg/kg) improves survival in lethal trauma models, but effectiveness of lower doses on survival is unknown. This information is essential for properly designing the upcoming clinical trials. We, therefore, performed the current study to determine the lowest dose at which VPA administration improves survival in a model of lethal injuries.

METHODS

Swine were subjected to traumatic brain injury (10-mm cortical impact), 40% blood volume hemorrhage, and multiple trauma (femur fracture, rectus crush, and Grade V liver laceration). After 1 hour of shock, animals were randomized (n = 6/group) to four groups: normal saline (NS) resuscitation; or NS with VPA doses of 150 mg/kg (VPA 150) or 100 mg/kg (VPA 100) administered over 3 hours or 100 mg/kg over 2 hours (VPA 100 over 2 hours). Three hours after shock, packed red blood cells were given, and animals were monitored for another 4 hours. Survival was assessed using Kaplan-Meier and log-rank test.

RESULTS

Without resuscitation, all of the injured animals died within 5 hours. Similar survival rates were observed in the NS (17%) and VPA 100 (0%) resuscitation groups. Survival rates in the 100-mg/kg VPA groups were significantly (p < 0.05) better when it was given over 2 hours (67%) compared to 3 hours (0%). 83% of the animals in the VPA 150 group survived, which was significantly higher than the NS and VPA 100 over 3 hours groups (p < 0.05).

CONCLUSION

A single dose of VPA (150 mg/kg) significantly improves survival in an otherwise lethal model of multiple injuries. This is a much lower dose than previously shown to have a survival benefit and matches the dose that is tolerated by healthy human subjects with minimal adverse effects.

LEVEL OF EVIDENCE

Therapeutic, level V.

Vibration Does Not Affect Short Term Outcomes Following Traumatic Brain Injury in a Porcine Model

Introduction

Traumatic brain injury (TBI) has become increasingly prevalent among the injuries sustained in the military. Many wounded warriors require emergency medical evacuation via helicopter and subsequently fixed wing transport. During aeromedical evacuation, both pilots and patients experience whole body vibration due to engine, rotor, and propeller rotation. The impact of posttraumatic vibration and hypoxia exposure characteristic of the aeromedical evacuation environment on TBI is currently unknown.

Methods

A swine TBI model of controlled cortical impact was utilized. The pigs first underwent TBI or sham injury and were subsequently exposed to vibration or no vibration and hypoxia or normoxia for 2 hours. They were monitored for an additional 4 hours following vibration/hypoxia and blood was drawn at hourly intervals for cytokine and serum biomarker analysis. Continuous physiologic and neurologic monitoring were utilized. Prior to the conclusion of the experiment, the animals underwent brain magnetic resonance imaging. At the end of the study, the brain was extracted for histologic analysis.

Results

Physiologic parameters except for peripheral capillary oxygen saturation (SpO2) were similar between all groups. The hypoxia groups demonstrated the expected decrease in SpO2 and pO2 during the hypoxic period, and this was sustained throughout the study period. The pH, pCO2 and electrolytes were similar among all groups. Neuron specific enolase was increased over time in the TBI group, however it was similar to the sham TBI group at all time points. There were no differences in IL-1β, IL-6, IL-8, TNFα, GFAP, HIF1α, syndecan-1, or S100β serum levels between groups. The mean ICP during cortical impact in the TBI group was 279.8 ± 56.2 mmHg. However, the postinjury ICP was not different between groups at any subsequent time point. Brain tissue oxygenation and perfusion were similar between all groups.

Conclusion

In this novel study evaluating the effect of vibration on short-term outcomes following TBI, we demonstrate that the moderate vibration and hypoxia simulating aeromedical evacuation do not impact short term outcomes following TBI.

Early single-dose treatment with exosomes provides neuroprotection and improves blood-brain barrier integrity in swine model of traumatic brain injury and hemorrhagic shock

BACKGROUND

Administration of human mesenchymal stem cell (MSC)-derived exosomes can enhance neurorestoration in models of traumatic brain injury (TBI) and hemorrhagic shock (HS). The impact of early treatment with MSC-derived exosomes on brain injury in a large animal model remains unknown. We sought to evaluate the impact of early single-dose exosome treatment on brain swelling and lesion size, blood-based cerebral biomarkers, and blood-brain barrier (BBB) integrity.

METHODS

Female Yorkshire swine were subjected to a severe TBI (12-mm cortical impact) and HS (40% estimated total blood volume). One hour into shock, animals were randomized (n = 5/cohort) to receive either lactated Ringer's (LR; 5 mL) or LR + exosomes (1 × 10 exosome particles in 5 mL LR). Animals then underwent additional shock (1 hour) followed by normal saline resuscitation. After 6 hours of observation, brain swelling (% increase compared with the uninjured side) and lesion size (mm) were assessed. Cerebral hemodynamics and blood-based biomarkers of brain injury were compared. Immunofluorescence and RNA sequencing with differential gene expression and pathway analysis were used to assess the integrity of the perilesion BBB.

RESULTS

Exosome-treated animals had significantly less (p < 0.05) brain swelling and smaller lesion size. They also had significantly decreased (p < 0.05) intracranial pressures and increased cerebral perfusion pressures. Exosome-treated animals had significantly decreased (p < 0.05) albumin extravasation and significantly higher (p < 0.05) laminin, claudin-5, and zonula occludens 1 levels. Differential gene expression and pathway analysis confirmed these findings. Serum glial fibrillary acidic protein levels were also significantly lower (p < 0.05) in the exosome-treated cohort at the end of the experiment.

CONCLUSION

In a large animal model of TBI and HS, early treatment with a single dose of MSC-derived exosomes significantly attenuates brain swelling and lesion size, decreases levels of blood-based cerebral biomarkers, and improves BBB integrity.

Post-treatment with oxcarbazepine confers potent neuroprotection against transient global cerebral ischemic injury by activating Nrf2 defense pathway

Oxcarbazepine (OXC), a voltage-gated sodium channel blocker, is an antiepileptic medication and used for the bipolar disorders treatment. Some voltage-gated sodium channel blockers have been demonstrated to display strong neuroprotective properties in models of cerebral ischemia. However, neuroprotective effects and mechanisms of OXC have not yet been reported. Here, we investigated the protective effect of OXC and its mechanisms in the cornu ammonis 1 subfield (CA1) of gerbils subjected to 5 min of transient global cerebral ischemia (tGCI). tGCI led to death of most pyramidal neurons in CA1 at 5 days after ischemia. OXC (100 and 200 mg/kg) was intraperitoneally administered once at 30 min after tGCI. Treatment with 200 mg/kg, not 100 mg/kg OXC, significantly protected CA1 pyramidal neurons from tGCI-induced injury. OXC treatment significantly decreased superoxide anion production, 4-hydroxy-2-nonenal and 8-hydroxyguanine levels in ischemic CA1 pyramidal neurons. In addition, the treatment restored levels of superoxide dismutases, catalase, and glutathione peroxidase. Furthermore, the treatment distinctly inhibited tGCI-induced microglia activation and significantly reduced levels of pro-inflammatory cytokines (interleukin-1β and tumor necrosis factor-α). In particular, OXC treatment significantly enhanced expressions of nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream protein heme oxygenase-1 in ischemic CA1. The neuroprotective effects of OXC were abolished by brusatol (an inhibitor of Nrf2). Taken together, these results indicate that post-treatment of OXC can display neuroprotection against brain injuries following ischemic insults. This neuroprotection may be displayed by attenuation of oxidative stress and neuroinflammation, which can be mediated by activation of Nrf2 pathway.

Valproic acid improves survival and decreases resuscitation requirements in a swine model of prolonged damage control resuscitation

BACKGROUND

Although damage control resuscitation (DCR) is routinely performed for short durations, prolonged DCR may be required in military conflicts as a component of prolonged field care. Valproic acid (VPA) has been shown to have beneficial properties in lethal hemorrhage/trauma models. We sought to investigate whether the addition of a single dose of VPA to a 72-hour prolonged DCR protocol would improve clinical outcomes.

METHODS

Fifteen Yorkshire swine (40-45 kg) were subjected to lethal (50% estimated total blood volume) hemorrhagic shock (HS) and randomized to three groups: (1) HS, (2) HS-DCR, (3) HS-DCR-VPA (150 mg/kg over 3 hours) (n = 5/cohort). In groups assigned to receive DCR, Tactical Combat Casualty Care guidelines were applied (1 hour into the shock period), targeting a systolic blood pressure of 80 mm Hg. At 72 hours, surviving animals were given transfusion of packed red blood cells, simulating evacuation to higher echelons of care. Survival rates, physiologic parameters, resuscitative fluid requirements, and laboratory profiles were used to compare the clinical outcomes.

RESULTS

This model was 100% lethal in the untreated animals. DCR improved survival to 20%, although this was not statistically significant. The addition of VPA to DCR significantly improved survival to 80% (p < 0.01). The VPA-treated animals also had significantly (p < 0.05) higher systolic blood pressures, lower fluid resuscitation requirements, higher hemoglobin levels, and lower creatinine and potassium levels.

CONCLUSION

VPA administration improves survival, decreases resuscitation requirements, and improves hemodynamic and laboratory parameters when added to prolonged DCR in a lethal hemorrhage model.

Traumatic Brain Injury Temporal Proteome Guides KCC2-Targeted Therapy

Advancing therapeutics for traumatic brain injury (TBI) remains a challenge, necessitating testable targets with interventions appropriately timed to intercede on evolving secondary insults. Neuroproteomics provides a global molecular approach to deduce the complex post-translational processes that underlie secondary events after TBI. Yet method advancement has outpaced approaches to interrogate neuroproteomic complexity, in particular when addressing the well-recognized temporal evolution of TBI pathobiology. Presented is a detailed account of the temporal neuroproteomic response to mild-moderate rat controlled cortical impact within perilesioned somatosensory neocortex across the first two weeks after injury. Further, this investigation assessed use of artificial neural network and functional enrichment analyses to discretize the temporal response across some 2047 significantly impacted proteins. Results were efficiently narrowed onto ion transporters with phenotypic relevance to abnormal GABAergic transmission and a delayed decline amenable to intervention under managed care conditions. The prototypical target potassium/chloride co-transporter 2 (KCC2 or SLC12A5) was investigated further with the KCC2-selective modulator CLP290. Guided by post-translational processing revealed one-day after insult to precede KCC2 protein loss a day after, CLP290 was highly effective at restoring up to 70% of lost KCC2 localization, which was significantly correlated with recovery of sham-level function in assessed somatosensory behavioral tasks. The timing of administration was important, with no significant improvement observed if given earlier, one-hour after insult, or later when KCC2 protein decline begins. Results portend importance for a detailed post-translational characterization when devising TBI treatments, and support the therapeutic promise of KCC2-targeted CLP290 intervention for positive functional recovery after brain injury.

Valproic acid affects neuronal fate and microglial function via enhancing autophagic flux in mice after traumatic brain injury

In recent years, many studies have focused on autophagy, an evolutionarily conserved mechanism that relies on lysosomes to achieve cellular metabolic requirements and organelle turnover, and revealed its important role in animal models of traumatic injury. Autophagy is a double-edged sword. Appropriate levels of autophagy can promote the removal of abnormal proteins or damaged organelles, while hyperactivated autophagy can induce autophagic apoptosis. However, recent studies suggest that autophagic flux seems to be blocked after traumatic brain injury (TBI), which contributes to the apoptosis of brain cells. In this study, valproic acid (VPA), which was clinically used for epilepsy treatment, was used to treat TBI. The Morris water maze test, hematoxylin & eosin staining and Nissl staining were first conducted to confirm that VPA treatment had a therapeutic effect on mice after TBI. Western blotting, enzyme-linked immunosorbent assay and immunofluorescence staining were then performed to reveal that VPA treatment reversed TBI-induced blockade of autophagic flux, which was accompanied by a reduced inflammatory response. In addition, the variations in activation and phenotypic polarization of microglia were observed after VPA treatment. Nevertheless, the use of the autophagy inhibitor 3-methyladenine partially abolished VPA-induced neuroprotection and the regulation of microglial function after TBI, resulting in the deterioration of the central nervous system microenvironment and neurological function. Collectively, VPA treatment reversed the TBI-induced blockade of autophagic flux in the mouse brain cortex, subsequently inhibiting brain cell apoptosis and affecting microglial function to achieve the promotion of functional recovery in mice after TBI. Cover Image for this issue: doi: 10.1111/jnc.14755.

Comparative analysis of isoform-specific and non-selective histone deacetylase inhibitors in attenuating the intestinal damage after hemorrhagic shock

BACKGROUND

Isoform-specific histone deacetylase inhibitors (HDACIs) MC1568 and ACY1083 are comparable to the non-selective HDACI valproic acid (VPA) in improving survival in rodents undergoing lethal hemorrhage. However, the organ-specific properties of isoform-specific HDACIs have not been fully evaluated. Also, whether they can act synergistically is not known. We hypothesized that isoform-specific HDACIs are superior to VPA in attenuating intestinal injury and act synergistically when coadministered.

METHODS

Sprague Dawley rats were hemorrhaged (40% of total blood volume) and randomized to receive (n=4 per group) (1) MC1568 (5 mg/kg), (2) ACY1083 (30 mg/kg), (3) MC1568+ACY1083 (combination: 5 mg/kg + 30 mg/kg, respectively), (4) VPA (250 mg/kg), or (5) normal saline (NS; vehicle; 250 μL). Animals were observed for 3 hours, after which blood samples were collected and samples of the ileum were harvested. Expression of interleukin 1 beta (IL-1β), tumor necrosis factor alpha (TNF-α), and cytokine-induced neutrophil chemoattractant 1 (CINC-1) was assessed in the tissues using enzyme-linked immunosorbent assay. Intestinal cleaved caspase 3 (c-caspase 3) levels were assessed as a marker of apoptosis, and histologic sections of the ileum were examined for signs of bowel injury. Levels of IL-1β and TNF-α were also measured in the serum as global markers of inflammation.

RESULTS

Treatments with MC1568, ACY1083, MC1568+ACY1083, and VPA were associated with decreased IL-1β levels in the intestine and serum compared with NS. IL-1β and TNF-α levels were significantly lower in the ACY1083 group compared with the VPA group. CINC-1 levels were significantly lower in the isoform-specific HDACI groups compared with the NS; however, no significant differences were seen with VPA. All treatment groups had a lower expression of intestinal c-caspase 3 compared with NS. Furthermore, MC1568 and ACY1083 groups had lower apoptosis compared with the VPA group. Bowel injury scores were significantly lower in the isoform-specific HDACI groups compared with the NS group; however, the attenuation in the VPA-treated animals did not reach statistical significance.

DISCUSSION

Isoform-specific HDACIs provide superior intestinal protection compared with VPA in a rodent model of hemorrhagic shock.

LEVEL OF EVIDENCE

Preclinical study.

The 'Omics' of Epigenetic Modulation by Valproic Acid Treatment in Traumatic Brain Injury-What We Know and What the Future Holds

Traumatic brain injury (TBI) is a heterogeneous injury that is a major cause of morbidity and mortality worldwide. Epigenetic modulation through the alteration of cellular acetylation by valproic acid (VPA) administration has shown promise as a novel pharmacological treatment for TBI. It improves clinical outcomes through multiple mechanisms, many of which are still poorly understood. In recent years, omics technologies have emerged as a promising strategy to detect molecular changes at the cellular level. This review highlights the use of these high throughput technologies in advancing the understanding of epigenetic modulation by VPA in TBI. It also describes the future role of omics techniques in developing a point of care test to guide patient selection for VPA administration.

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.

Annexin A1 Bioactive Peptide Promotes Resolution of Neuroinflammation in a Rat Model of Exsanguinating Cardiac Arrest Treated by Emergency Preservation and Resuscitation

Neuroinflammation initiated by damage-associated molecular patterns, including high mobility group box 1 protein (HMGB1), has been implicated in adverse neurological outcomes following lethal hemorrhagic shock and polytrauma. Emergency preservation and resuscitation (EPR) is a novel method of resuscitation for victims of exsanguinating cardiac arrest, shown in preclinical studies to improve survival with acceptable neurological recovery. Sirtuin 3 (SIRT3), the primary mitochondrial deacetylase, has emerged as a key regulator of metabolic and energy stress response pathways in the brain and a pharmacological target to induce a neuronal pro-survival phenotype. This study aims to examine whether systemic administration of an Annexin-A1 bioactive peptide (ANXA1sp) could resolve neuroinflammation and induce sirtuin-3 regulated cytoprotective pathways in a novel rat model of exsanguinating cardiac arrest and EPR. Adult male rats underwent hemorrhagic shock and ventricular fibrillation, induction of profound hypothermia, followed by resuscitation and rewarming using cardiopulmonary bypass (EPR). Animals randomly received ANXA1sp (3 mg/kg, in divided doses) or vehicle. Neuroinflammation (HMGB1, TNFα, IL-6, and IL-10 levels), cerebral cell death (TUNEL, caspase-3, pro and antiapoptotic protein levels), and neurologic scores were assessed to evaluate the inflammation resolving effects of ANXA1sp following EPR. Furthermore, western blot analysis and immunohistochemistry were used to interrogate the mechanisms involved. Compared to vehicle controls, ANXA1sp effectively reduced expression of cerebral HMGB1, IL-6, and TNFα and increased IL-10 expression, which were associated with improved neurological scores. ANXA1sp reversed EPR-induced increases in expression of proapoptotic protein Bax and reduction in antiapoptotic protein Bcl-2, with a corresponding decrease in cerebral levels of cleaved caspase-3. Furthermore, ANXA1sp induced autophagic flux (increased LC3II and reduced p62 expression) in the brain. Mechanistically, these findings were accompanied by upregulation of the mitochondrial protein deacetylase Sirtuin-3, and its downstream targets FOXO3a and MnSOD in ANXA1sp-treated animals. Our data provide new evidence that engaging pro-resolving pharmacological strategies such as Annexin-A1 biomimetic peptides can effectively attenuate neuroinflammation and enhance the neuroprotective effects of EPR after exsanguinating cardiac arrest.

Systematic review and meta-analysis of experimental studies evaluating the organ protective effects of histone deacetylase inhibitors

The clinical efficacy of organ protection interventions are limited by the redundancy of cellular activation mechanisms. Interventions that target epigenetic mechanisms overcome this by eliciting genome wide changes in transcription and signaling. We aimed to review preclinical studies evaluating the organ protection effects of histone deacetylase inhibitors (HDACi) with a view to informing the design of early phase clinical trials. A systematic literature search was performed. Methodological quality was assessed against prespecified criteria. The primary outcome was mortality, with secondary outcomes assessing mechanisms. Prespecified analyses evaluated the effects of likely moderators on heterogeneity. The analysis included 101 experimental studies in rodents (n = 92) and swine (n = 9), exposed to diverse injuries, including: ischemia (n = 72), infection (n = 7), and trauma (n = 22). There were a total of 448 comparisons due to the evaluation of multiple independent interventions within single studies. Sodium valproate (VPA) was the most commonly evaluated HDACi (50 studies, 203 comparisons). All of the studies were judged to have significant methodological limitations. HDACi reduced mortality in experimental models of organ injury (risk ratio = 0.52, 95% confidence interval 0.40-0.68, p < 0.001) without heterogeneity. HDACi administration resulted in myocardial, brain and kidney protection across diverse species and injuries that was attributable to increases in prosurvival cell signaling, and reductions in inflammation and programmed cell death. Heterogeneity in the analyses of secondary outcomes was explained by differences in species, type of injury, HDACi class (Class I better), drug (trichostatin better), and time of administration (at least 6 hours prior to injury better). These findings highlight a potential novel application for HDACi in clinical settings characterized by acute organ injury.

Traumatic brain injury may worsen clinical outcomes after prolonged partial resuscitative endovascular balloon occlusion of the aorta in severe hemorrhagic shock model

BACKGROUND

The use of partial resuscitative endovascular balloon occlusion of the aorta (pREBOA) in combined hemorrhagic shock (HS) and traumatic brain injury (TBI) has not been well studied. We hypothesized that the use of pREBOA in the setting of TBI would be associated with worse clinical outcomes.

METHODS

Female Yorkshire swine were randomized to the following groups: HS-TBI, HS-TBI-pREBOA, and HS-pREBOA (n = 5/cohort). Animals in the HS-TBI group were left in shock for a total of 2 hours, whereas animals assigned to pREBOA groups were treated with supraceliac pREBOA deployment (60 minutes) 1 hour into the shock period. All animals were then resuscitated, and physiologic parameters were monitored for 6 hours. Further fluid resuscitation and vasopressors were administered as needed. At the end of the observation period, brain hemispheric swelling (%) and lesion size (mm) were assessed.

RESULTS

Mortality was highest in the HS-TBI-pREBOA group (40% [2/5] vs. 0% [0/5] in the other groups, p = 0.1). Severity of shock was greatest in the HS-TBI-pREBOA group, as defined by peak lactate levels and pH nadir (p < 0.05). Fluid resuscitation and norepinephrine requirements were significantly higher in the HS-TBI-pREBOA group (p < 0.05). No significant differences were noted in brain hemispheric swelling and lesion size between the groups.

CONCLUSION

Prolonged application of pREBOA in the setting of TBI does not contribute to early worsening of brain lesion size and edema. However, the addition of TBI to HS-pREBOA may worsen the severity of shock. Providers should be aware of the potential physiologic sequelae induced by TBI.

Valproic Acid and Neural Apoptosis, Inflammation, and Degeneration 30 Days after Traumatic Brain Injury, Hemorrhagic Shock, and Polytrauma in a Swine Model

BACKGROUND

A single-dose (150 mg/kg) of valproic acid (VPA) has been shown to decrease brain lesion size and improve neurologic recovery in preclinical models of traumatic brain injury (TBI). However, the longer-term (30 days) impact of single-dose VPA treatment after TBI has not been well evaluated.

STUDY DESIGN

Yorkshire swine were subjected to TBI (cortical impact), hemorrhagic shock, and polytrauma. Animals remained in hypovolemic shock for 2 hours before resuscitation with normal saline (NS; volume = 3× hemorrhaged volume) or NS + VPA (150 mg/kg) (n = 5/cohort). Brain samples were harvested 30 days after injuries. The cerebral cortex adjacent to the site of cortical impact was evaluated using terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, immunohistochemistry, and Western blot analysis. Neural apoptosis, inflammation, degeneration, plasticity, and signaling pathways were evaluated.

RESULTS

For apoptosis, VPA treatment significantly decreased (p < 0.05) the number of TUNEL (+) cells and expression of cleaved-caspase 3. For inflammation and degeneration, expression of ionized calcium binding adaptor molecule-1, glial fibrillary acid protein, amyloid-β, and phosphorylated-Tau protein were significantly attenuated (p < 0.05) in the VPA-treated animals compared with the NS group. For, plasticity, VPA treatment also increased expression of brain-derived neurotrophic factor significantly (p < 0.05) compared with the NS group. For signaling pathways, nuclear factor-κB was decreased significantly (p < 0.05) and cytosolic IκBα expression was increased significantly (p < 0.05) in the VPA-treated animals compared with the NS group.

CONCLUSIONS

Administration of a single dose of VPA (150 mg/kg) can decrease neural apoptosis, inflammation, and degenerative changes, and promote neural plasticity at 30 days after TBI. In addition, VPA acts, in part, via regulation of nuclear factor-κB and IκBα pathways.

HDAC inhibitor valproic acid protects heart function through Foxm1 pathway after acute myocardial infarction

BACKGROUND

Epigenetic histone acetylation is a major event controlling cell functions, such as metabolism, differentiation and repair. Here, we aim to determine whether Valproic acid (VPA), a FDA approved inhibitor of histone deacetylation for bipolar disease, could protect heart against myocardial infarction (MI) injury and elucidate key molecular pathways.

METHODS

VPA was administrated to MI rats at different time points, onset and after MI injury. Echocardiography, histology, serum biology assays, and gene expression, inhibition, and over-expression were performed to characterize the systolic function, infarct size, gene and signaling pathways.

FINDINGS

VPA treatment reduced the infarct size by ~50% and preserved the systolic function of heart after acute MI in rats. Even 60 min after infarction, VPA treatment significantly decreased infarct size. Furthermore, long-term treatment of VPA markedly improved myocardial performance. VPA regulated gene expression essential for cell survival and anti-inflammatory response. Consequently, oxidative stress and cell death were notably reduced after VPA treatment. Moreover, Foxm1 was identified as a potential key target of VPA. Overexpression of Foxm1 provided similar heart protective effect to VPA treatment. Particularly, both VPA treatment and Foxm1 over-expression repressed inflammatory response after MI for heart protection. In contrast, inhibition of Foxm1 activity abolished the cardiac protective effect of VPA. VPA mediated CM protection through Foxm1 upregulation was also identified in a human ESC derived CM hypoxia/reperfusion system.

INTERPRETATION

VPA treatments significantly reduce cardiac damage after MI and the cardioprotective effect of VPA is likely mediated via Foxm1 pathway. FUND: This work was mainly supported by 1R01HL109054.

Complete and Partial Aortic Occlusion for the Treatment of Hemorrhagic Shock in Swine

Hemorrhage remains the leading cause of preventable deaths in trauma. Endovascular management of non-compressible torso hemorrhage has been at the forefront of trauma care in recent years. Since complete aortic occlusion presents serious concerns, the concept of partial aortic occlusion has gained a growing attention. Here, we present a large animal model of hemorrhagic shock to investigate the effects of a novel partial aortic balloon occlusion catheter and compare it with a catheter that works on the principles of complete aortic occlusion. Swine are anesthetized and instrumented in order to conduct controlled fixed-volume hemorrhage, and hemodynamic and physiological parameters are monitored. Following hemorrhage, aortic balloon occlusion catheters are inserted and inflated in the supraceliac aorta for 60 min, during which the animals receive whole-blood resuscitation as 20% of the total blood volume (TBV). Following balloon deflation, the animals are monitored in a critical care setting for 4 h, during which they receive fluid resuscitation and vasopressors as needed. The partial aortic balloon occlusion demonstrated improved distal mean arterial pressures (MAPs) during the balloon inflation, decreased markers of ischemia, and decreased fluid resuscitation and vasopressor use. As swine physiology and homeostatic responses following hemorrhage have been well-documented and are like those in humans, a swine hemorrhagic shock model can be used to test various treatment strategies. In addition to treating hemorrhage, aortic balloon occlusion catheters have become popular for their role in cardiac arrest, cardiac and vascular surgery, and other high-risk elective surgical procedures.

Mesenchymal Stem Cell-Derived Exosomes Provide Neuroprotection and Improve Long-Term Neurologic Outcomes in a Swine Model of Traumatic Brain Injury and Hemorrhagic Shock

Combined traumatic brain injury (TBI) and hemorrhagic shock (HS) remains a leading cause of preventable death worldwide. Mesenchymal stem cell-derived exosomes have demonstrated promise in small animal models of neurologic injury. To investigate the effects of exosome treatment in a clinically realistic large animal model, Yorkshire swine underwent TBI and HS. Animals were maintained in shock for 2 h before resuscitation with normal saline (NS). Animals were then resuscitated either with NS (3 × volume of shed blood) or with the same volume of NS with delayed exosome administration (1 × 10¹³ particles/4 mL) (n = 5/cohort). Exosomes were administered 9 h post-injury, and on post-injury days (PID) 1, 5, 9, and 13. Neurologic severity scores (NSS) were assessed for 30 days, and neurocognitive functions were objectively measured. Exosome-treated animals had significantly lower NSS (p < 0.05) during the first five days of recovery. Exosome-treated animals also had a significantly shorter time to complete neurologic recovery (NSS = 0) compared with animals given NS alone (days to recovery: NS = 16.8 ± 10.6; NS + exosomes = 5.6 ± 2.8; p = 0.03). Animals treated with exosomes initiated neurocognitive testing earlier (days to initiation: NS = 9.6 ± 0.5 vs. NS + exosomes = 4.2 ± 0.8; p = 0.008); however, no difference was seen in time to mastery of tasks. In conclusion, treatment with exosomes attenuates the severity of neurologic injury and allows for faster neurologic recovery in a clinically realistic large animal model of TBI and HS.

Histone deacetylase inhibitors: Isoform selectivity improves survival in a hemorrhagic shock model

BACKGROUND

Hemorrhage is a leading preventable cause of death. Nonselective histone deacetylase inhibitors (HDACIs), such as valproic acid (VPA), have been shown to improve outcomes in hemorrhagic shock (HS). The HDACs can be divided into four functional classes (I, IIa/IIb, III, and IV). Classes I, IIa/IIb, and III have previously been implicated in the pathophysiology of HS. This study aimed to determine which HDAC class, or classes, are responsible for the survival benefit observed with nonselective HDACIs.

METHODS

Survival study: Sprague-Dawley rats were subjected to lethal HS (50% hemorrhage) and randomized to the following groups (n = 8): (1) no treatment, (2) normal saline vehicle, (3) cyclodextrin vehicle, (4) MS275 (class I HDACI), (5) VPA (class I/IIa HDACI), (6) MC1568 (class IIa HDACI), (7) ACY1083 (class IIb HDACI), and (8) EX527 (class III HDACI). Survival was monitored for 24 hours. Mechanistic study: Sprague-Dawley rats were subjected to sublethal HS (40% hemorrhage) and randomized to the same groups (n = 3), excluding EX527, based on results of the survival study. Tissues were harvested at 3 hours posttreatment, and expression of phosphorylated-AKT, β-catenin, acetylated histones H3 and H4, and acetylated α-tubulin were analyzed in myocardial tissue.

RESULTS

Survival rate was 12.5% in the untreated group, and did not improve with vehicle or MS275 treatment. EX527 improved survival to 50%, although this did not achieve statistical significance (p = 0.082). However, treatment with VPA, MC1568, and ACY1083 improved survival rates to 87.5%, 75%, and 75%, respectively (p < 0.05). The VPA-induced acetylation of both histones H3 and H4, while MC1568 and ACY1083 increased acetylation of histone H4. ACY1083 also induced acetylation of α-tubulin. All treatment groups, except MS275, increased phosphorylated-AKT, and β-catenin.

CONCLUSION

Inhibition of HDAC classes IIa or IIb, but not class I, activates prosurvival pathways, which may be responsible for the improved outcomes in rodent models of HS.

Valproic Acid Attenuates Traumatic Brain Injury-Induced Inflammation in Vivo: Involvement of Autophagy and the Nrf2/ARE Signaling Pathway

Microglial activation and the inflammatory response in the central nervous system (CNS) play important roles in secondary damage after traumatic brain injury (TBI). Transcriptional activation of genes that limit secondary damage to the CNS are mediated by a cis-acting element called the antioxidant responsive element (ARE). ARE is known to associate with the transcription factor NF-E2-related factor 2 (Nrf2), a transcription factor that is associated with histone deacetylases (HDACs). This pathway, known as the Nrf2/ARE pathway, is a critical antioxidative factor pathway that regulates the balance of oxygen free radicals and the inflammatory response, and is also related to autophagic activities. Although valproic acid (VPA) is known to inhibit HDACs, it is unclear whether VPA plays a role in the microglia-mediated neuroinflammatory response after TBI via regulating oxidative stress and autophagy induced by the Nrf2/ARE signaling pathway. In this study, we demonstrate that microglial activation, oxidative stress, autophagy, and the Nrf2/ARE signaling pathway play essential roles in secondary injury following TBI. Treatment with VPA alleviated TBI-induced secondary brain injury, including neurological deficits, cerebral edema, and neuronal apoptosis. Moreover, VPA treatment upregulated the occurrence of autophagy and Nrf2/ARE pathway activity after TBI, and there was an increase in H3, H4 histone acetylation levels, accompanied by decreased transcriptional activity of the HDAC3 promoter in cortical lesions. These results suggest that VPA-mediated up-regulation of autophagy and antioxidative responses are likely due to increased activation of Nrf2/ARE pathway, through direct inhibition of HDAC3. This inhibition further reduces TBI-induced microglial activation and the subsequent inflammatory response, ultimately leading to neuroprotection.

Valproic acid induces prosurvival transcriptomic changes in swine subjected to traumatic injury and hemorrhagic shock

BACKGROUND

Valproic acid (VPA) is a histone deacetylase inhibitor that improves outcomes in large animal models of trauma. However, its protective mechanism of action is not completely understood. We sought to characterize the genetic changes induced by VPA treatment following traumatic injuries.

METHODS

Six female Yorkshire swine were subjected to traumatic brain injury (controlled cortical impact), polytrauma (liver and splenic laceration, rib fracture, rectus crush), and hemorrhagic shock (HS, 40% total blood volume). Following 2 hours of HS, animals were randomized to resuscitation with normal saline (NS) or NS + 150 mg/kg of intravenous VPA (n = 3/cohort, 18 samples total). Blood samples were collected for isolation of peripheral blood mononuclear cells at three distinct time points: baseline, 6 hours following injuries, and on postinjury day 1. RNA was extracted from peripheral blood mononuclear cells and sequenced. Differential expression analysis (false discovery rate < 0.001 and p value <0.001) and gene set enrichment (Panther Gene Ontology and Ingenuity Pathway Analysis) was used to compare VPA to non-VPA-treated animals.

RESULTS

A total of 628 differentially expressed RNA transcripts were identified, 412 of which were used for analysis. There was no difference between treatment groups at baseline. The VPA-induced genetic changes were similar at 6 hours and on postinjury day 1. Upregulated genes were associated with gene expression (p 2.13E-34), cellular development (1.19E-33), cellular growth and proliferation (1.25E-30), and glucocorticoid receptor signaling (8.6E-21). Downregulated genes were associated with cell cycle checkpoint regulation (3.64E-22), apoptosis signaling (6.54E-21), acute phase response signaling (5.84E-23), and the inflammasome pathway (1.7E-19).

CONCLUSION

In injured swine, VPA increases the expression of genes associated with cell survival, proliferation, and differentiation and decreases those associated with cell death and inflammation. These genetic changes could explain the superior clinical outcomes in VPA-treated animals, including smaller brain lesion size and improved neurologic recovery.

Valproic Acid Treatment Decreases Serum Glial Fibrillary Acidic Protein and Neurofilament Light Chain Levels in Swine Subjected to Traumatic Brain Injury

The primary aim of this study was to examine the effects of valproic acid (VPA) treatment on serum glial fibrillary acidic protein (GFAP) and neurofilament light chain (NF-L) levels. To achieve this aim, we obtained serum samples from: 1) 10 Yorkshire swine subjected to controlled cortical impact traumatic brain injury (CCI TBI) + polytrauma and randomized to receive either normal saline (NS) + VPA (n = 5) or NS alone (n = 5) and 2) five additional swine subjected to CCI TBI without polytrauma and treated with VPA. GFAP and NF-L levels were measured in samples obtained from baseline until 10 days post-injury using a digital immunoassay from Quanterix Corporation. We found that elevated GFAP and NF-L levels were first detected at 2 h post-injury; and peaked at 24 h and 72 h respectively. GFAP levels returned to baseline levels by Day 10, while NF-L remained elevated at Day 10. In TBI + polytrauma swine, the magnitude and duration of biomarker elevation, quantified by the area under the biomarker-concentration-versus-time curve during the first 10 days (AUC_0-10days), was higher in the NS group, compared with the VPA group. For GFAP, the AUC_0-10days was 45,535 (IQR: 35,741-105,711) and 22,837 (IQR: 8,082-46,627) for the NS and NS+VPA groups, respectively. For NF-L, the AUC_0-10days was 43,073 (IQR: 18,739-120,794) and 4,475 (2,868-11,157) for the NS and NS+VPA groups, respectively. Twenty-four hour GFAP and NF-L levels had the strongest correlation with lesion size and time to normalization of behavior. Accordingly, we conclude that treatment with VPA results in significantly lower serum GFAP and NF-L levels. The time-point at which GFAP and NF-L levels have the strongest correlation with outcome is 24 h post-injury.

Innate immune responses to trauma

Trauma can affect any individual at any location and at any time over a lifespan. The disruption of macrobarriers and microbarriers induces instant activation of innate immunity. The subsequent complex response, designed to limit further damage and induce healing, also represents a major driver of complications and fatal outcome after injury. This Review aims to provide basic concepts about the posttraumatic response and is focused on the interactive events of innate immunity at frequent sites of injury: the endothelium at large, and sites within the lungs, inside and outside the brain and at the gut barrier.

Transcriptomic changes following valproic acid treatment promote neurogenesis and minimize secondary brain injury

BACKGROUND

Early treatment with valproic acid (VPA) has demonstrated benefit in preclinical models of traumatic brain injury, including smaller brain lesion size, decreased edema, reduced neurologic disability, and faster recovery. Mechanisms underlying these favorable outcomes are not fully understood. We hypothesized that VPA treatment would upregulate genes involved in cell survival and proliferation and downregulate those associated with cell death and the inflammatory response.

METHODS

Ten female swine were subjected to a protocol of traumatic brain injury and hemorrhagic shock. They were assigned to two groups (n = 5): normal saline (NS; 3× volume of shed blood), or NS + VPA (150 mg/kg). Following 6 hours of observation, brain tissue was harvested to evaluate lesion size and edema. Brain tissue was processed for RNA sequencing. Gene set enrichment and pathway analysis was performed to determine the differential gene expression patterns following injury.

RESULTS

Animals treated with VPA were noted to have a 46% reduction in brain lesion size and a 57% reduction in ipsilateral brain edema. Valproic acid significantly upregulated genes involved in morphology of the nervous system, neuronal development and neuron quantity. The VPA treatment downregulated pathways related to apoptosis, glial cell proliferation, and neuroepithelial cell differentiation. Ingenuity Pathway Analysis identified VPA as the top upstream regulator of activated transcription, supporting it as a direct cause of these transcriptional changes. Master transcriptional regulator NEUROD1 was also significantly upregulated, suggesting that VPA may induce additional transcription factors.

CONCLUSION

Administration of VPA attenuated brain lesion size, reduced brain edema, and induced significant changes in the transcriptome of injured brain within 6 hours. Patterns of differential expression were consistent with the proposed neurogenic and prosurvival effects of VPA treatment.