Understanding recovery from TBI is complex, involving multiple systems and modalities. The current study applied modern data science tools to manage this complexity and harmonize large-scale data to understand relationships between gene expression and behavioral outcomes in a preclinical model of chronic TBI (cTBI). Data collected by the Moody Project for Translational TBI Research included rats with no injury (naïve animals with similar amounts of anesthetic exposure to TBI and sham-injured animals), sham injury, or lateral fluid percussion TBI, followed by recovery periods up to 12 months. Behavioral measures included locomotor coordination (beam balance neuroscore) and memory and cognition assessments (Morris water maze: MWM) at multiple timepoints. Gene arrays were performed using hippocampal and cortical samples to probe 45,610 genes. To reduce the high dimensionality of molecular and behavioral domains and uncover gene–behavior associations, we performed non-linear principal components analyses (NL-PCA), which de-noised the data. Genomic NL-PCA unveiled three interpretable eigengene components (PC2, PC3, and PC4). Ingenuity pathway analysis (IPA) identified the PCs as an integrated stress response (PC2; EIF2-mTOR, corticotropin signaling, etc.), inflammatory factor translation (PC3; PI3K-p70S6K signaling), and neurite growth inhibition (PC4; Rho pathways). Behavioral PCA revealed three principal components reflecting the contribution of MWM overall speed and distance, neuroscore/beam walk, and MWM platform measures. Integrating the genomic and behavioral domains, we then performed a ‘meta-PCA’ on individual PC scores for each rat from genomic and behavioral PCAs. This meta-PCA uncovered three unique multimodal PCs, characterized by robust associations between inflammatory/stress response and neuroscore/beam walk performance (meta-PC1), stress response and MWM performance (meta-PC2), and stress response and neuroscore/beam walk performance (meta-PC3). Multivariate analysis of variance (MANOVA) on genomic–behavioral meta-PC scores tested separately on cortex and hippocampal samples revealed the main effects of TBI and recovery time. These findings are a proof of concept for the integration of disparate data domains for translational knowledge discovery, harnessing the full syndromic space of TBI.

The release of excess glutamate following traumatic brain injury (TBI) results in glutamate excitotoxicity and metabolic energy failure. Endogenous mechanisms for reducing glutamate concentration in the brain parenchyma following TBI are poorly understood. Using multiple mass spectrometry approaches, we examined TBI-induced changes to glutamate metabolism. We present evidence that glutamate concentration can be reduced by glutamate oxidation via a "truncated" tricarboxylic acid cycle coupled to the urea cycle. This process reduces glutamate levels, generates carbon for energy metabolism, leads to citrulline accumulation, and produces nitric oxide. Several key metabolites are identified by metabolomics in support of this mechanism and the locations of these metabolites in the injured hemisphere are demonstrated by MALDI-MS imaging. The results of this study establish the advantages of multiple mass spectrometry approaches and provide insights into glutamate metabolism following TBI that could lead to improved treatment approaches.

High-throughput sequencing technologies could improve diagnosis and classification of TBI subgroups. Because recent studies showed that circulating microRNAs (miRNAs) may serve as noninvasive markers of TBI, we performed miRNA-seq to study TBI-induced changes in rat hippocampal miRNAs up to one year post-injury. We used miRNA PCR arrays to interrogate differences in serum miRNAs using two rat models of TBI (controlled cortical impact [CCI] and fluid percussion injury [FPI]). The translational potential of our results was evaluated by miRNA-seq analysis of human control and TBI (acute and chronic) serum samples. Bioinformatic analyses were performed using Ingenuity Pathway Analysis, miRDB, and Qlucore Omics Explorer. Rat miRNA profiles identified TBI across all acute and chronic intervals. Rat CCI and FPI displayed distinct serum miRNA profiles. Human miRNA profiles identified TBI across all acute and chronic time points and, at 24 hours, discriminated between focal and diffuse injuries. In both species, predicted gene targets of differentially expressed miRNAs are involved in neuroplasticity, immune function and neurorestoration. Chronically dysregulated miRNAs (miR-451a, miR-30d-5p, miR-145-5p, miR-204-5p) are linked to psychiatric and neurodegenerative disorders. These data suggest that circulating miRNAs in biofluids can be used as “molecular fingerprints” to identify acute, chronic, focal or diffuse TBI and potentially, presence of neurodegenerative sequelae.

Journal of NeurotraumaVol. 37, No. 22 IntroductionFree AccessIntroduction to the Special Issue on TranslationDouglas DeWitt and Donald S. ProughDouglas DeWittAddress correspondence to: Douglas DeWitt, PhD, Department of Anesthesiology, University of Texas Medical Branch, 301 University Boulevard, Suite 2A, Galveston, TX 77555, USA E-mail Address: ddewitt@utmb.eduDepartment of Anesthesiology, University of Texas Medical Branch, Galveston, Texas, USA.Search for more papers by this author and Donald S. ProughDepartment of Anesthesiology, University of Texas Medical Branch, Galveston, Texas, USA.Search for more papers by this authorPublished Online:28 Oct 2020https://doi.org/10.1089/neu.2020.7390AboutSectionsPDF/EPUB Permissions & CitationsPermissionsDownload CitationsTrack CitationsAdd to favorites Back To Publication ShareShare onFacebookTwitterLinked InRedditEmail Despite the numerous promising neuroprotective agents identified in experimental traumatic brain injury (TBI) studies, none has shown meaningful improvement in long-term outcome in hundreds of clinical trials conducted over the last few decades.1–3 Included among the myriad reasons for the limited translational success of pharmacological therapies for TBI are major differences in the types and times of collection of outcome variables between clinical and pre-clinical studies4 and the limited number of pre-clinical studies involving multiple TBI models and/or multiple species.5,6 In addition to these and other limitations in pre-clinical therapy testing, the validity of many clinical trials has been reduced by inadvertent bias,7 and the relatively large number of single-center1 and underpowered clinical trials.8,9 These and other potential reasons for the failure of candidate therapies to translate to successful randomized controlled trials (RCTs) and clinical benefits in patients with TBI are discussed in greater detail in several recent reviews.4,10–13This special issue on translation is intended to address some of the challenges associated with the successful transition of potentially effective pharmacological therapies from laboratory studies to clinical practice.Kochanek and colleagues describe traditional and novel approaches to the identification and pre-clinical development of effective therapies for TBI such as Operation Brain Trauma Therapy (OBTT), a multi-center consortium that has provided pre-clinical testing of 12 potential therapies for TBI in three rodent TBI models. Also, they suggest that the incorporation of biomarkers into pre-clinical testing could enhance the choice and assessment of target engagements of potential therapies, that drug combinations may be more effective in some patients, and that precision medicine approaches may improve therapeutic efficacy by linking specific therapies to specific patients by more accurate TBI classification and/or pathophysiological phenotyping. Finally, they describe Targeted Evaluation, Action, and Monitoring of TBI (TEAM TBI), a group of investigators at the University of Pittsburgh Brain Trauma Research Center who are using symptomatic phenotyping to characterize patients, develop targeted treatment regimens, and assess the efficacy of therapies for mild TBI.Therapies that appear promising in pre-clinical testing are more likely to translate to successful clinical trials if they result in improvements in behavioral outcomes that are relevant to humans. Shultz and colleagues summarize the behavioral consequences of TBI in humans and describe behavioral tasks appropriate for experimental animals that measure the functional outcomes that are most often assessed in patients with TBI. Additionally, they provide an overview of the results of studies using clinically relevant behavioral tasks in experimental models of TBI, focusing on pre-clinical behavior methods and findings in terms of their relevance to studies in patients with TBI. Finally, they outline strategies and future research to improve the clinical relevance of behavior testing in animal models of TBI.Poloyac and colleagues describe the pharmacological barriers to the successful development of drug therapies for TBI and discuss strategies to overcome these barriers. They review pharmacological considerations for moving from disease targets to lead compounds with drug-like and central nervous system (CNS) penetrant properties. The authors describe the use of in vitro assessments of drug-like properties, followed by pre-clinical studies in vivo to ensure accurate identification of the pharmacokinetic and pharmacodynamic characteristics of response. Poloyac and colleagues highlight the importance of biomarker development and utilization in pre-clinical and clinical studies as well as the importance of the identification of diagnostic, pharmacodynamic/response and prognostic biomarkers of injury type or severity, target engagement, and disease progression. Their review describes important considerations in determining pre-clinical dose selection in vivo and cross-species and human equivalent dose selection and the use of allometric scaling, and pharmacokinetic and pharmacodynamic criteria for clinical trial design.As noted above, one of the potential reasons for the lack of successful translation of promising pre-clinical therapies is the limited use of large animals in pre-clinical testing. To address this problem, Armstead and colleagues describe the use of reverse translation of bedside experience to improve the design of pre-clinical studies in a porcine model of TBI that accurately replicates practical clinical assessments. In patients with TBI, cerebral perfusion pressure (CPP) is often normalized using vasoactive agents to increase mean arterial pressure (MAP) and counteract the effects of impaired cerebral autoregulation and improve neurological outcomes. However, to date, the effects of many of these vasoactive agents (e.g., phenylephrine, dopamine, norepinephrine, and epinephrine) on CPP, autoregulation, and survival after TBI have not been thoroughly explored. Armstead and colleagues describe a bidirectional translational approach using a clinically relevant large-animal model of TBI to better identify therapeutic strategies designed to improve outcome post-injury.Issadore and colleagues describe their open-ended search for panels of microRNA (miRNA) biomarkers contained in extracellular vesicles (EVs) that will more accurately classify various states of injury. They analyzed samples from experimental studies using a variety of murine injury types, injury intensities, history of injuries, and times post-injury, as well as samples from patients with TBI. Using next-generation sequencing coupled with Track Etched Magnetic Nanopore (TENPO) sorting, a technique developed in their laboratories, they enriched the GluR2+ EVs and profiled their miRNA. These innovative methods resulted in the mapping and comparing of brain-derived EV miRNA between various injuries, thereby identifying signaling pathways that connect these biomarkers to underlying mechanisms of TBI in the pre-clinical model and the clinical samples. They then applied machine learning to define a panel of biomarkers to successfully classify specific states of injury, paving the way for a prognostic blood test for TBI.Glushakova and colleagues observed that, although intracranial pressure (ICP) is one of the most common neurologically specific physiological variables used to direct the care of patients with severe TBI (sTBI). Recent clinical evidence has called into question the association of ICP monitoring with improved clinical outcome. The specific cellular and molecular derangements associated with intracranial hypertension (IC-HTN) and their relationship to neurological outcomes are not well understood. Additionally, despite decades of research using a variety of experimental TBI models, the clinical applicability of ICP monitoring in the pre-clinical setting has not been established. Glushakova and colleagues suggest that the linking of basic mechanistic studies in TBI models with investigations of ICP monitoring that more accurately replicate the clinical setting will provide clinicians with a better understanding of the pathophysiology of IC-HTN, thus facilitating development of improved therapies for patients with sTBI.Hawkins and colleagues suggest that TBI translation is a problem of big-data that can be best addressed using modern data science approaches. They summarize the history of the term “big-data,” which originated in Internet technology as data that are big according to the four “Vs” of volume, velocity, variety, or veracity, and then transitioned into the mainstream of biomedical research. They suggest that TBI translation fundamentally involves data variety, a problem that could best be addressed using modern machine learning and other cutting-edge analytical approaches. Further, they discuss the importance of acquiring data from diverse sources including unpublished sources (i.e., “dark data”) and long-tail data (small, specialty TBI data sets undergirding the published literature).14 Finally, they summarize the results of published articles describing pre-clinical and clinical TBI research to suggest ways that data reuse can drive new discoveries leading to successful translation of TBI therapies. Ideally, these methods will facilitate the development of TBI data resources that are more Findable, Accessible, Interoperable, and Reusable (FAIR) to accelerate discovery and translation for the silent epidemic of TBI.References1. Bragge , P., Synnot , A., Maas , A.I., Menon , D.K., Cooper , D.J., Rosenfeld , J.V., and Gruen , R.L. (2016). A state-of-the-science overview of randomized controlled trials evaluating acute management of moderate-to-severe traumatic brain injury. J. Neurotrauma 33, 1461–1478. Link, Google Scholar2. Burke , M.J., Fralick , M., Nejatbakhsh , N., Tartaglia , M.C., and Tator , C.H. (2015). In search of evidence-based treatment for concussion: characteristics of current clinical trials. Brain Inj. 29, 300–305. Crossref, Medline, Google Scholar3. Marklund , N., Bakshi , A., Castelbuono , D.J., Conte , V., and McIntosh , T. (2006). Evaluation of pharmacological treatment strategies in traumatic brain injury. Curr. Pharm. Des. 12, 1645–1680. Crossref, Medline, Google Scholar4. Agoston , D.V., Risling , M., and Bellander , B.-M. (2012). Bench-to-bedside and bedside back to the bench; coordinating clinical and experimental traumatic brain injury studies. Front. Neurol. 3, 1–5. Crossref, Medline, Google Scholar5. Kochanek , P.M., Bramlett , H.M., Dixon , C.E., Shear , D.A., Dietrich , W.D., Schmid , K.E., Mondello , S., Wang , K.K.W., Hayes , R.L., Povlishock , J.T., and Tortella , F.C. (2016). Approach to modeling, therapy evaluation, drug selection, and biomarker assessments for a multicenter pre-clinical drug screening consortium for acute therapies in severe traumatic brain injury: Operation Brain Trauma Therapy. J. Neurotrauma 33, 513–522. Link, Google Scholar6. Loane , D.J., and Faden , A.I. (2010). Neuroprotection for traumatic brain injury: translational challenges and emerging therapeutic strategies. Trends Pharmacol. Sci. 31, 596–604. Crossref, Medline, Google Scholar7. Page , M.J., Higgins , J.P., Clayton , G., Sterne , J.A.C., Hrobjartsson , A., and Savovic , J. (2016). Empirical evidence of study design biases in randomized trials: systematic review of meta-epidemiological studies. PLoS One 11, e0159267. Crossref, Medline, Google Scholar8. Button , K.S., Ioannidis , J.P.A., Mokrysz , C., Nosek , B.A., Flint , J., Robinson , E.S.J., and Munafo , M.R. (2013). Power failure: why small sample size undermines the reliability of neuroscience. Nat. Rev. Neurosci. 14, 365–376. Crossref, Medline, Google Scholar9. Egger , M., Davey-Smith , G., Schneider , M., and Minder , C. (1997). Bias in meta-analysis detected by a simple, graphical test. Brit. Med. J. 315, 629–634. Crossref, Medline, Google Scholar10. Hawkyrluk , G.W.J., and Bullock , M.R. (2015). Design of acute neuroprotection studies, in: Handbook of Clinical Neurology, Traumatic Brain Injury, Part II, Vol. 128, J. Grafman, and A.M. Salazar (eds). ScienceDirect, pps. 761–778. Google Scholar11. Menon , D.K. (2009). Unique challenges in clinical trials in traumatic brain injury. Crit. Care Med. 37, S129–S135. Crossref, Medline, Google Scholar12. Stocchetti , N., Taccone , F.S., Citerio , G., Pepe , P.E., Le Roux , P.D., Oddo , M., Polderman , K.H., Stevens , R.D., Barsan , W., Maas , A.I., Meyfroidt , G., Bell , M.J., Silbergleit , R., Vespa , P.M., Faden , A.I., Helbok , R., Tisherman , S., Zanier , E.R., Valenzuela , T., Wendon , J., Menon , D.K., and Vincent , J.L. (2015). Neuroprotection in acute brain injury: an up- to-date review. Crit. Care 19, 186. Crossref, Medline, Google Scholar13. DeWitt , D.S., Hawkins , B.E., Dixon , C.E., Kochanek , P.M., Armstead , W., Bass , C.R., Bramlett , H.M., Buki , A., Dietrich , W.D., Ferguson , A.R., Hall , E.D., Hayes , R.L., Hinds , S.R., LaPlaca , M.C., Long , J.B., Meaney , D.F., Mondello , S., Noble-Haeusslein , L.J., Poloyac , S.M., Prough , D.S., Robertson , C.S., Saatman , K.E., Shultz , S.R., Shear , D.A., Smith , D.H., Valadka , A.B., VandeVord , P., and Zhang , L. (2018). Preclinical testing of therapies for traumatic brain injury. J. Neurotrauma 35, 2737–2754. Link, Google Scholar14. Ferguson , A.R., Nielson , J.L., Cragin , M.H., Bandrowski , A., and Martone , M.E. (2014). Big data from small data: data-sharing in the ‘long tail’ of neuroscience. Nat. Neurosci. 17, 1442–1448. Crossref, Medline, Google ScholarFiguresReferencesRelatedDetails Volume 37Issue 22Nov 2020 InformationCopyright 2020, Mary Ann Liebert, Inc., publishersTo cite this article:Douglas DeWitt and Donald S. Prough.Introduction to the Special Issue on Translation.Journal of Neurotrauma.Nov 2020.2351-2352.http://doi.org/10.1089/neu.2020.7390Published in Volume: 37 Issue 22: October 28, 2020Online Ahead of Editing: August 25, 2020PDF download

Background Sepsis is one of the most frequent causes of death in the intensive care unit. Host vascular hypo-responsiveness to vasopressors during septic shock is one of the challenging problems. This study tested the hypothesis that adjunct therapy with peroxynitrite decomposition catalyst (WW-85) would reduce arginine vasopressin (AVP) requirements during sepsis resuscitation, using ovine sepsis model. Methods Thirteen adult female Merino sheep, previously instrumented with multiple vascular catheters, were subjected to “two-hit” (cotton smoke inhalation and intrapulmonary instillation of live methicillin-resistant Staphylococcus aureus ; 3.5 × 10 11 colony-forming units) injury. Post injury, animals were awakened and randomly allocated to the following groups: (1) AVP: injured, fluid resuscitated, and titrated with AVP, n = 6 or (2) WW-85 + AVP: injured, fluid resuscitated, treated with WW-85, and titrated with AVP, n = 7. One-hour post injury, a bolus intravenous injection of WW-85 (0.1 mg/kg) was followed by a 23-h continuous infusion (0.02 mg/kg/h). Titration of AVP started at a dose of 0.01 unit/min, when mean arterial pressure (MAP) decreased by 10 mmHg from baseline, despite aggressive fluid resuscitation, and the rate was further adjusted to maintain MAP. After the injury, all animals were placed on a mechanical ventilator and monitored in the conscious state for 24 h. Results The injury induced severe hypotension refractory to aggressive fluid resuscitation. High doses of AVP were required to partially attenuate the sepsis-induced hypotension. However, the cumulative AVP requirement was significantly reduced by adjunct treatment with WW-85 at 17–24 h after the injury ( p < 0.05). Total AVP dose and the highest AVP rate were significantly lower in the WW-85 + AVP group compared to the AVP group ( p = 0.02 and 0.04, respectively). Treatment with WW-85 had no adverse effects. In addition, the in vitro effects of AVP on isolated artery diameter changes were abolished with peroxynitrite co-incubation. Conclusions The modulation of reactive nitrogen species, such as peroxynitrite, may be considered as a novel adjunct treatment option for septic shock associated with vascular hypo-responsiveness to vasopressors.

There are no existing treatments for the long-term degenerative effects of traumatic brain injury (TBI). This is due, in part, to our limited understanding of chronic TBI and uncertainty about which proposed mechanisms for long-term neurodegeneration are amenable to treatment with existing or novel drugs. Here, we used microarray and pathway analyses to interrogate TBI-induced gene expression in the rat hippocampus and cortex at several acute, subchronic and chronic intervals (24 hours, 2 weeks, 1, 2, 3, 6 and 12 months) after parasagittal fluid percussion injury. We used Ingenuity pathway analysis (IPA) and Gene Ontology enrichment analysis to identify significantly expressed genes and prominent cell signaling pathways that are dysregulated weeks to months after TBI and potentially amenable to therapeutic modulation. We noted long-term, coordinated changes in expression of genes belonging to canonical pathways associated with the innate immune response (i.e., NF-κB signaling, NFAT signaling, Complement System, Acute Phase Response, Toll-like receptor signaling, and Neuroinflammatory signaling). Bioinformatic analysis suggested that dysregulation of these immune mediators-many are key hub genes-would compromise multiple cell signaling pathways essential for homeostatic brain function, particularly those involved in cell survival and neuroplasticity. Importantly, the temporal profile of beneficial and maladaptive immunoregulatory genes in the weeks to months after the initial TBI suggests wider therapeutic windows than previously indicated.

Department of Anesthesiology, The University of Texas Medical Branch at Galveston, Galveston, TX *See also p. 960. Dr. Prough received support for article research from the Moody Foundation. Dr. DeWitt has disclosed that he does not have any potential conflicts of interest.

Patients with traumatic brain injury (TBI) are frequently diagnosed with depression. Together, these two leading causes of death and disability significantly contribute to the global burden of healthcare costs. However, there are no drug treatments for TBI and antidepressants are considered off-label for depression in patients with TBI. In molecular profiling studies of rat hippocampus after experimental TBI, we found that TBI altered the expression of a subset of small, non-coding, microRNAs (miRNAs). One known neuroprotective compound (17β-estradiol, E2), and two experimental neuroprotective compounds (JM6 and PMI-006), reversed the effects of TBI on miRNAs. Subsequent in silico analyses revealed that the injury-altered miRNAs were predicted to regulate genes involved in depression. Thus, we hypothesized that drug-induced miRNA profiles can be used to identify compounds with antidepressant properties. To confirm this hypothesis, we examined miRNA expression in hippocampi of injured rats treated with one of three known antidepressants (imipramine, fluoxetine and sertraline). Bioinformatic analyses revealed that TBI, potentially via its effects on multiple regulatory miRNAs, dysregulated transcriptional networks involved in neuroplasticity, neurogenesis, and circadian rhythms- networks known to adversely affect mood, cognition and memory. As did E2, JM6, and PMI-006, all three antidepressants reversed the effects of TBI on multiple injury-altered miRNAs. Furthermore, JM6 reduced TBI-induced inflammation in the hippocampus and depression-like behavior in the forced swim test; these are both properties of classic antidepressant drugs. Our results support the hypothesis that miRNA expression signatures can identify neuroprotective and antidepressant properties of novel compounds and that there is substantial overlap between neuroprotection and antidepressant properties.

Though there have been studies on the histopathological and behavioral effects of blast exposure, fewer have been dedicated to blast's cerebral vascular effects. Impact (i.e., non-blast) traumatic brain injury (TBI) is known to decrease pressure autoregulation in the cerebral vasculature in both humans and experimental animals. The hypothesis that blast-induced traumatic brain injury (bTBI), like impact TBI, results in impaired cerebral vascular reactivity was tested by measuring myogenic dilatory responses to reduced intravascular pressure in rodent middle cerebral arterial (MCA) segments from rats subjected to mild bTBI using an Advanced Blast Simulator (ABS) shock tube. Adult, male Sprague-Dawley rats were anesthetized, intubated, ventilated and prepared for Sham bTBI (identical manipulation and anesthesia except for blast injury) or mild bTBI. Rats were randomly assigned to receive Sham bTBI or mild bTBI followed by sacrifice 30 or 60 min post-injury. Immediately after bTBI, righting reflex (RR) suppression times were assessed, euthanasia at the time points post-injury was completed, the brain was harvested and the individual MCA segments were collected, mounted and pressurized. As the intraluminal pressure perfused through the arterial segments was reduced in 20 mmHg increments from 100 to 20 mmHg, MCA diameters were measured and recorded. With decreasing intraluminal pressure, MCA diameters steadily increased significantly above baseline in the Sham bTBI groups while MCA dilator responses were significantly reduced (p < 0.05) in both bTBI groups as evidenced by the impaired, smaller MCA diameters recorded for the bTBI groups. In addition, RR suppression in the bTBI groups was significantly (p < 0.05) higher than in the Sham bTBI groups. MCA's collected from the Sham bTBI groups exhibited typical vasodilatory properties to decreases in intraluminal pressure while MCA's collected following bTBI exhibited significantly impaired myogenic vasodilatory responses to reduced pressure that persisted for at least 60 min after bTBI.

Vascular hypo-responsiveness to vasopressors during septic shock is a challenging problem. This study is to test the hypothesis that reactive nitrogen species (RNS), such as peroxynitrite, are major contributing factors to vascular hypo-responsiveness in septic shock. We hypothesized that adjunct therapy with peroxynitrite decomposition catalyst (PDC) would reduce norepinephrine requirements in sepsis resuscitation. Fourteen female Merino sheep were subjected to a "two-hit" injury (smoke inhalation and endobronchial instillation of live methicillin-resistant Staphylococcus aureus [1.6-2.5 × 10 CFUs]). The animals were randomly allocated to control: injured, fluid resuscitated, and titrated norepinephrine, n = 7; or PDC: injured, fluid resuscitated, titrated norepinephrine, and treated with PDC, n = 7. One-hour postinjury, an intravenous injection of PDC (0.1 mg/kg) was followed by a continuous infusion (0.04 mg/kg/h). Titration of norepinephrine started at 0.05 mcg/kg/min based on their mean arterial pressure. All animals were mechanically ventilated and monitored in the conscious state for 24 h. The mean arterial pressure was well maintained in the PDC with significantly less norepinephrine requirement from 7 to 23 h after injury compared with control. Total norepinephrine dose, the highest norepinephrine rate, and time on norepinephrine support were also significantly lower in PDC. Modified sheep organ failure assessment scores at 6 to 18 h postinjury were significantly lower in PDC compared with control. PDC improved survival rate at 24 h (71.4% vs. 28.6%). PDC treatment had no adverse effects. In conclusion, the modulation of RNS may be considered an effective adjunct therapy for septic shock, in the case of hypo-responsiveness to norepinephrine.

We have developed a novel, non-invasive nano-pulsed laser therapy (NPLT) system that combines the benefits of near-infrared laser light (808 nm) and ultrasound (optoacoustic) waves, which are generated with each short laser pulse within the tissue. We tested NPLT in a rat model of blast-induced neurotrauma (BINT) to determine whether transcranial application of NPLT provides neuroprotective effects. The laser pulses were applied on the intact rat head 1 h after injury using a specially developed fiber-optic system. Vestibulomotor function was assessed on post-injury days (PIDs) 1-3 on the beam balance and beam walking tasks. Cognitive function was assessed on PIDs 6-10 using a working memory Morris water maze (MWM) test. BDNF and caspase-3 messenger RNA (mRNA) expression was measured by quantitative real-time PCR (qRT-PCR) in laser-captured cortical neurons. Microglia activation and neuronal injury were assessed in brain sections by immunofluorescence using specific antibodies against CD68 and active caspase-3, respectively. In the vestibulomotor and cognitive (MWM) tests, NPLT-treated animals performed significantly better than the untreated blast group and similarly to sham animals. NPLT upregulated mRNA encoding BDNF and downregulated the pro-apoptotic protein caspase-3 in cortical neurons. Immunofluorescence demonstrated that NPLT inhibited microglia activation and reduced the number of cortical neurons expressing activated caspase-3. NPLT also increased expression of BDNF in the hippocampus and the number of proliferating progenitor cells in the dentate gyrus. Our data demonstrate a neuroprotective effect of NPLT and prompt further studies aimed to develop NPLT as a therapeutic intervention after traumatic brain injury (TBI).

Despite the large number of promising neuroprotective agents identified in experimental traumatic brain injury (TBI) studies, none has yet shown meaningful improvements in long-term outcome in clinical trials. To develop recommendations and guidelines for pre-clinical testing of pharmacological or biological therapies for TBI, the Moody Project for Translational Traumatic Brain Injury Research hosted a symposium attended by investigators with extensive experience in pre-clinical TBI testing. The symposium participants discussed issues related to pre-clinical TBI testing including experimental models, therapy and outcome selection, study design, data analysis, and dissemination. Consensus recommendations included the creation of a manual of standard operating procedures with sufficiently detailed descriptions of modeling and outcome measurement procedures to permit replication. The importance of the selection of clinically relevant outcome variables, especially related to behavior testing, was noted. Considering the heterogeneous nature of human TBI, evidence of therapeutic efficacy in multiple, diverse (e.g., diffuse vs. focused) rodent models and a species with a gyrencephalic brain prior to clinical testing was encouraged. Basing drug doses, times, and routes of administration on pharmacokinetic and pharmacodynamic data in the test species was recommended. Symposium participants agreed that the publication of negative results would reduce costly and unnecessary duplication of unsuccessful experiments. Although some of the recommendations are more relevant to multi-center, multi-investigator collaborations, most are applicable to pre-clinical therapy testing in general. The goal of these consensus guidelines is to increase the likelihood that therapies that improve outcomes in pre-clinical studies will also improve outcomes in TBI patients.