Helen M. Bramlett - US grants

Several laboratories using focal and diffuse models of traumatic brain injury (TBI) have reported the progressive nature of histopathological damage that can continue in rodent models up to one year. Evidence for progressive damage has previously been reported in humans following head trauma. Preliminary data in this application presented for the first time provides quantitative data for chronic white matter pathology following moderate fluid-percussion brain injury. The overall goal of the proposed studies is to assess the importance of moderate and severe TBI on long-term vulnerability patterns after trauma. In Specific Aim 1, regional patterns of gray and white matter pathology and their associated neurobehavioral alterations will be assessed. Histopathological techniques along with magnetic resonance imaging (MRI) strategies will be used to assess temporal and regional patterns of progressive damage in order to correlate these changes with behavioral outcomes. In Specific Aim 2, immunocytochemical markers of axonal damage, demyelination, cell atrophy, and cell death will be utilized to assess cellular injury progression. To begin to determine the pathomechanisms underlying progressive white matter injury, the role of prolonged hypoperfusion and abnormal protein aggregation on these structural changes will be regionally and temporally assessed. Finally, therapeutic strategies targeting excitotoxic processes as well as abnormal protein aggregation will be evaluated to reduce progression of advancing atrophy. It is felt that these experiments are necessary to understand the pathogenesis of progressive injury as well as to develop therapeutic strategies to promote recovery of function following TBI. Established animal models and behavioral, MRI, immunocytochemical, autoradiography, and molecular techniques will be utilized.

DESCRIPTION (provided by applicant): The efficacy of estrogen treatment in several injury models has been previously reported. Our own recent work has demonstrated a reduction in contusion volumes following traumatic brain injury (TBI) in female rats versus males or ovariectomized females. Although several mechanistic pathways for this neuroprotection have been explored, one that has not and is important after TBI is inflammation. TBI produces a robust inflammatory response that is both acute and chronic in duration. Several investigators using other models have reported the ability of estrogen to inhibit specific components of the inflammatory cascade. The proposed studies will assess differences between males and females after TBI with regard to post-traumatic inflammation. Four specific aims are proposed to address this issue. In specific aim 1, we will measure levels of proinflammatory cytokines and determine the cellular source of these initiators of inflammation. These studies will provide novel data on differences between males and females and in addition, by using ovariectomized females, the influence of reproductive steroids. In the second aim, we will study regional patterns of iNOS expression and determine if this response is sex and hormone-dependent. Because iNOS has been implicated in the pathogenesis of TBI, this inflammatory response to trauma requires investigation in the present setting. Specific aim 3 will assess whether estrogen's effect on the inflammatory cascade after TBI is due to antioxidant properties or receptor-mediated mechanisms. Because estrogen has been reported to effect various components of the inflammatory cascade, its effect on trauma-induced inflammatory processes requires further investigation. Results from this study will provide novel data for the potential use of neurohormones in the treatment of TBI. In the final aim, estrogen isomers or specific estrogen receptor antagonist/agonist will be administered after TBI to assess recovery of function. Taken together, these experiments will provide new data on the importance of neurohormones on structural and functional outcome after TBI. Established methods including rodent models of TBI, behavioral tests, as well as immunocytochemical and molecular approaches will be used in this proposal.

The purpose of the General Scientific Core B is to assist investigators in animal surgery, electrophysiology, immunocytochemistry, transmission electron microscopy, and image analysis requirements for the Program Project faculty. The Core also assists investigators in various biochemical analyses and viral vector production. The Core facilities consist of personnel and equipment needed to perform the proposed studies in Projects 1 through 3. This Core will conduct general animal preparation, including anesthesia, intubation, catheterization, temperature monitoring, and regulation of physiological variables. The Core will assist investigators in preparing the animals for traumatic brain injury, as described in the individual projects. In addition, expertise is available to modify experimental animal preparations that may be required for future investigations. Core personnel will perform perfusion, fixation, and removal of brains for light and electron microscopic examination. Core personnel will carry out immunocytochemical procedures, as well as develop new procedures for the visualization of additional antibodies. The Core will process tissue for plastic embedding for both light and electron microscopic analysis. High quality thin sections will be produced by personnel within this Core and stained for ultrastructural analysis. Established image analysis procedures using non-biased stereological procedures to quantify the frequency of immunoreactive cells, as well as to determine contusion areas and volumes will be utilized.

? DESCRIPTION (provided by applicant): Neurotrauma is the largest cause of death and disability for persons under the age of 45 in the world and the societal cost of the resulting disability exceeds $60 billion per year in the United States. The National Neurotrauma Society (NNS) Annual Symposium is the primary forum for exchanging information in the fields of both traumatic brain injury (TBI) and spinal cord injury (SCI). The National Neurotrauma Symposium is now in its 33rd year and has been primarily a forum for integrating new information regarding the pathophysiology and treatment of brain and SCI for many years. This application seeks funding to support 20 pre- and postdoctoral trainees to attend the 33rd National Neurotrauma Symposium and partial support for travel of 56 invited speakers. The meeting will be held in Santa Fe, New Mexico at their Convention Center. The 3-day meeting will focus on important and timely topics in the field of Neurotrauma including basic, translational and clinical investigations. The 2015 meeting is co-hosted by the National Neurotrauma Society (NNS) and the AANS/CNS Joint Section on Neurotrauma and Critical Care (AANAS/CNS JSNCC). Members from both societies are included on the Program Planning Committee to be certain there is a sufficient mix of topics targeting both brain and SCI. An exciting collection of state-f-the-art sessions on the consequences of damage to the nervous system and treatment strategies for protection and repair are planned. Highlights of the scientific program include new investigators and new visions for CNS injury research, inflammation after trauma, aging with spinal cord injury, emerging imaging strategies for detection and diagnosis of neurotrauma, cell therapies including preclinical and clinical outcomes as well as the importance of genetic indicators of a predisposition for neurotrauma. Other sessions include genetic dissection of locomotive circuitry, the use of therapeutic hypothermia and targeted temperature management after neurotrauma, as well as a variety of other important topics that would be of interest to scientists and clinicians. We have tried to incorporate speakers and topics that have not previously been emphasized in prior meetings. There will be a special workshop hosted by the Women in Neurotrauma (WiNTR) devoted to human TBI neuropathology. Several networking events will also be organized in order to maximize opportunities for students and young investigators to interact with established researchers. Due to the growing concern of mild traumatic brain injury in the field of neurotrauma, a session on the clinical science of sports concussion as well as executive function after experimental TBI will emphasize the growing knowledge in this emerging field. Two patient perspectives will provide personal viewpoints on living with injury and their views regarding scientific progress in the field of Neurotrauma.

? DESCRIPTION (provided by applicant): Traumatic brain injury (TBI) is a major public health problem associated with pathophysiological mechanisms linked with progressive structural and long-term functional consequences. Although many of the molecular events underlying cellular susceptibility and functional deficits after TBI have been characterized, the successful translation of therapies to the clinic has been unsuccessful. One reason for these translational failures is the appreciation that TBI is not a single acute event but a chronic disease process that necessitates a polytherapeutic approach targeting both acute and chronic injury events. Targeted temperature management (TTM) protocols, including therapeutic hypothermia protect the microenvironment after trauma and may promote reparative mechanisms. In addition, classes of molecules have been recently identified that promote neurogenic processes and enhance cognitive recovery. Compounds including the highly-active agent P7C3-A20 have favorable pharmacological profiles and augment both hippocampal neurogenesis and the survival of newborn neurons. We have recently reported that early cooling and P7C3-A20 treatment each individually is neuroprotective and enhance reparative processes at early intervals after TBI. These findings emphasize that therapeutic hypothermia and neurogenic compounds are pertinent therapeutic interventions to augment protection and promote regenerative mechanisms that contribute to cognition. The goal of this proposal is to test the hypothesis that posttraumatic hypothermia and the P7C3 class of molecules act by targeting a range of mechanisms in terms of their respective protective and reparative properties and that the combination of these treatments will lead to superior preservation of hippocampal-dependent memory. The first Aim is to characterize the effects hypothermia and hyperthermia has on microglia/macrophage phenotypes and reparative processes. Two complementary TBI models using rats and transgenic mice with cutting edge 3D imaging will examine the functions of adult neurogenesis. The Nestind-TK-GFP transgenic mice will allow neurogenesis to be independently manipulated to assess causal links to functional improvement with treatments. Aim 2 will test the translational potential of P7C3-A20 using rat and mouse transgenic models to again independently manipulate neurogenesis and relate to functional outcome. Based on the newly proposed binding properties of this class of molecules to nicotinamide phosphoribosyltransferase, an important step for the production of nicotinamide adenosine dinucleotide, we will evaluate the treatment effects on this metabolic pathway as an essential mechanism of protecting hippocampal precursor cells. Finally, Aim 3 will test whether a novel combinatorial treatment with therapeutic hypothermia and P7C3-A20 leads to greater cytoprotection, hippocampal neurogenesis and improved cognitive function relative to single treatments. These studies will help clarify mechanisms underlying posttraumatic temperature modifications and proneurogenic therapies and thereby preserving the microenvironment, hippocampal neurogenesis and memory function.