P. David Adelson - US grants

The candidate's overall objective is to obtain sufficient independence and accomplishment as a clinical and basic science investigator and develop an academic career in pediatric neurosurgery with a research focus on brain injury and neuroplasticity in the immature. The MCSDA will provide the opportunity to devote the majority of time to research to develop a strong foundation in basic science, clinical research and teaching in the area of traumatic brain injury in children in the early stages of career development. This application proposes a basic science project with clearly accomplishable aims important for the understanding of the pathologic response of the immature brain to traumatic injury and combines this project with an active clinical program of head injury in children. This proposal is unique since the study of TBI in immatures has been hampered by the lack of a model producing a diffuse cerebral injury. We modified the recently described, diffuse closed-head injury model of Marmarou et al. (53) and have begun to characterize this model of diffuse TBI in immature (17 d) rats (3,4). In this application, we propose to further characterize this diffuse TBI model in the immature rat using two clinically available outcome parameters, namely function (motor and cognitive) and cerebral blood flow (CBF) and we will then use hypothermia to determine its effect on these parameters after diffuse TBI. The specific aims of the proposal are: l) to characterize the motor and cognitive (spatial memory acquisition and retention) deficits produced in the acute and chronic phases after diffuse TBI (closed head injury weight-drop) in immature (17 d) rats; 2) to describe the acute and chronic changes in CBF (hyperemia vs ischemia) and CO2 vasoresponsivity after this injury; and 3) to determine if moderate hypothermia (32 +/- 0.5 degrees C) applied in the acute period after diffuse TBI will reduce the functional, CBF, and histologic disturbances acutely and chronically in immature rats. The aims will be accomplished by performing serial assessments of functional outcome (cognition and motor) and determining CBF using iodo[14C] antipyrine (14C-IAP) autoradiography. Perfusion magnetic resonance imaging, (pMRI), a noninvasive serial assessment of regional CBF will be validated to autoradiography and then CO2 vasoresponsivity will be tested using pMRl following hyperventilation. Lastly, we will utilize moderate hypothermia after injury in this experimental model of TBI in the immature rat to determine its effect on function, CBF, and histology. Characterization of the functional, cerebrovascular and histologic disturbances in this unique model of diffuse brain injury should yield the first clues as to the mechanism(s) of diffuse swelling in the immature. Also this proposal should facilitate the development and testing of targeted therapies for eventual use after severe TBI in infants and children and provide important pre-clinical data for the multi-center trial of hypothermia in children.

To determine whether: 1) a reduction in regional cerebral oxygen availability (detected by NIRS) signaling impending cerebral ischemia correlates with a reduction in CBF as measured by either beside, radioactive 133Xe or stable Xe-enhanced CT and with other indices indicative of reduced cerebral perfusion such as increased ICP or reduced CPP; 2) an increased cerebral oxygen availability (as detected by NIRS) indicates cerebrovascular dilation and vasoparalysis. A reduction in CBV indicates cerebral edema in the genesis of intracranial hypertension; 3) application of appropriate therapy with successful reduction in ICP and increase in CPP correlates with increased cerebral availability.

induced hypothermia; child (0-11); pediatrics; brain injury; human therapy evaluation; intracranial pressure; neurology; nervous system disorder diagnosis; data collection methodology /evaluation; neurologic manifestations; diagnosis design /evaluation; disease /disorder classification; clinical research; questionnaires; diagnostic catheterization; medical records; human subject; fiber optics;

To date no know studies have assessed for cases of post-traumatic stress disorder in children following accidental head injury. The present research seeks to identify the prevalence of PTSD and the variables associated with the development of the disorder, in a sample of 40 head injured children and 40 control subjects with orthopedic injuries. Eighty children ages 5 and older and their parents will be included in the study. Based on information obtained from history, variables such as severity of injury and course of recovery will be taken into consideration. Parents will be administered a diagnostic interview to assess personality and the extent of psychopathology. At a later follow-up appointment, children will be interviewed and assessed with self-report measures of depression, anxiety, and PTSD. Multiple regression analysis will be used to examine the influence of subject, family, and injury variables on the development of PTSD, and on increased overall psychological morbidity.

induced hypothermia; child (0-11); pediatrics; brain injury; human therapy evaluation; intracranial pressure; neurology; nervous system disorder diagnosis; data collection methodology /evaluation; neurologic manifestations; diagnosis design /evaluation; disease /disorder classification; clinical research; questionnaires; diagnostic catheterization; medical records; human subject; fiber optics;

Treatment of traumatic brain injury (TBI) in the pediatric population has been totally dependent on adult paradigms, both experimentally and clinically with little attention paid to the potential unique responses of the developing brain after injury. There has been few experimental studies utilizing immature animals and even fewer clinical studies utilizing treatment interventions following pediatric TBI (e.g.) Hypothermia (HYPO). While there is over-whelming experimental evidence that HYPO is neuroprotective in a wide spectrum of different models of TBI, studies in children or utilizing immature models of TBI have been lacking. It is obvious that despite the evidence available in the adult, so little is known of the effect of HYPO following experimental and clinical pediatric TBI that it necessitates further study. Despite the recent disappointing results from the adult clinical trials using hypothermia, there was a suggestion of improved outcome in younger patients that may extend to the pediatric population. Efficacy from this study through cannot be translated to care of children since none of the patients in this trial were children and HYPO following pediatric TBI cannot be either prematurely discarded or utilized as a therapeutic intervention without further study. Based on the previous literature and our Preliminary Data, HYPO may be potentially more beneficial in children as compared to the adult. This initial data is compelling evidence for further study as to the potential children, there is currently no understanding of the potential age dependent impact nor limitations of HYPO treatment following pediatric TBI on subsequent neural development. Our Overall Hypothesis for this proposal is that while HYPO will be beneficial in the treatment of pediatric TBI, it will have an age related impact on development at different ages of injury and treatment.. This age at injury and treatment effect will in turn be governed by the sensitivity of the developing brain to neurotransmitter release and/or subsequent blockade. While HYPO following experimental and clinical pediatric TBI will positively impact on the attenuation of neurotransmitter release in all maturational ages, an age related effect, due to either inadequate blockade of excessive neurotransmitter release or the negative impact of neurotransmitter blockade on normal development, will be evidenced in post-injury markers of cell death, synaptic connectivity, and cognitive function. The Specific Aims will include defining the neurotransmitter release response following treatment with HYPO and the subsequent age related impact of injury and treatment of histologic damage, both early and delayed neuronal cell death, synaptogenesis, and functional outcome using different age at injury experimental models of TBI in the immature rat. Parallel clinical specific aims will define the effect of neurotransmitter release in response to treatment with HYPO and the age-related impact of HYPO on early and delayed cell death in children.

DESCRIPTION (provided by applicant): Despite preventative measures, traumatic brain injury (TBI) remains the leading cause of death and disability in children. While most pediatric treatment regimens for TBI to date are derived from adult studies, no therapeutic regimen has been particularly successful in improving outcome in children. There have been numerous laboratory studies utilizing moderate hypothermia (HYPO) (32-33[unreadable]C) in mature and immature animals, successful Phase II and III clinical studies in adult patients for 24 to 48 h after TBI, and a number of trials in children of HYPO following hypoxia-ischemic (HIE) brain injuries that have supported the efficacy of this intervention. The most recently published trial of treatment with HYPO for HIE within 6 hours showed significant improvement in outcome, particularly in mortality, as compared to severe disability. While the multi-center Phase III randomized controlled clinical trial (RCT) of moderate HYPO in adults was stopped early due to futility but not lack of efficacy, the secondary analysis did highlight that younger adult patients (<40 y) tended toward improved outcome compared to older subjects. This finding along with a trend toward improved outcomes with early cooling (<6 h) has resulted in a funded HYPO RCT specifically inclusive of patients ages 16- 45 y and early pre-hospital cooling that has recently begun. Based on the results from our Pilot Clinical Trial (PCT) utilizing moderate HYPO following severe TBI in children, the following application is for a multicenter Phase III RCT to determine whether induced early cooling (within 6 h) (32-33[unreadable]C) after severe TBI in children and maintained for 48 h will improve mortality at 3 mos post injury as compared to normothermia (37- 38[unreadable]C). The Secondary Hypotheses, again based on the analysis of the PCT, are that early HYPO after severe TBI in children and maintained for 48 h: 1) will improve global function as measured by the GOS/ GOS- Extended Pediatrics (GOS- E Peds) and neurocognitive status across the domains of intellectual development, learning and memory, and behavior at 6 and 12 mos after injury;2) will be more effective in younger children <6 y compared to older children, >6y, and 3) will lessen intracranial hypertension and the intensity of therapy necessary for control of ICP.

DESCRIPTION (provided by applicant): Traumatic brain injury, both from direct trauma to the brain and as a sequela of ischemic or hemorrhagic infarction are associated with a significant rate of morbidity, mortality and cost to both patients and the healthcare system. Hemorrhagic infarcts (such as aneurysmal subarachnoid hemorrhage and intraventricular hemorrhage) are rare but devastating complications of arterial rupture. Despite significant effort, there has been little improvement in the outcomes of patients with aneurysmal subarachnoid hemorrhage (aSAH) or intraventricular hemorrhage (IVH). Given the predictable temporal course of these brain injuries, they are ideal candidates for biomarker identification. A biomarker for detection o 'at risk' patients and a prognostic indicator of delayed neurological deficit would vastly improve current treatments and increase our understanding of underlying pathological events. This information would immediately lead to the implementation of new therapeutic strategies. Research over the last several years has identified extracellular RNAs (exRNA) as a potential source of biomarkers. New technology, such as next generation sequencing (NGS), has made it possible to sensitively and quantitatively assay small amounts of RNA contained in clinically attainable volumes of biofluids such as CSF and blood plasma. In the first two years of this grant, we propose to sequene the exRNA (miRNA and total RNA) from both the CSF and plasma of patients who present with aSAH and the plasma and CSF from premature infants born with IVH. aSAH samples were collected daily~ the volume of sample available will allow us not only to sequence the total RNA including miRNAs, but will permit us to explore unique enrichment strategies in years 3-5 of this grant~ we will examine specific RNAs associated with microvesicles in both CSF and plasma. We have both the daily clinical evaluations of these patients as well as their outcomes (25 subjects in all). We will use these samples to identiy RNA markers that predict onset of vasospasm and the severity of delayed neurological deficits. We also have CSF and plasma samples collected every other day from premature infants with grade III-IV IVH that had reservoirs put in place to evacuate blood and excess CSF. We also have the clinical outcomes from the infants, whether or not they developed hydrocephalus, the need for a permanent shunt, and an 18 month assessment of developmental delays or disabilities. In years 3-5, we will continue to collect samples in collaboration with both of our clinical partners. At that time, we will switch from our discovery platform, the Illumina HiSeq 2000 that has high depth of sequencing coverage, to the Illumina MiSeq for validation. Once the discovery phase is complete and potential biomarkers identified, validation can be carried out on the MiSeq's faster fluidics, imaging, and shortened run times without changing chemistries between the discovery and validation phases.

DESCRIPTION (provided by applicant): Traumatic brain injury, both from direct trauma to the brain and as a sequela of ischemic or hemorrhagic infarction are associated with a significant rate of morbidity, mortality and cost to both patients and the healthcare system. Hemorrhagic infarcts (such as aneurysmal subarachnoid hemorrhage and intraventricular hemorrhage) are rare but devastating complications of arterial rupture. Despite significant effort, there has been little improvement in the outcomes of patients with aneurysmal subarachnoid hemorrhage (aSAH) or intraventricular hemorrhage (IVH). Given the predictable temporal course of these brain injuries, they are ideal candidates for biomarker identification. A biomarker for detection o 'at risk' patients and a prognostic indicator of delayed neurological deficit would vastly improve current treatments and increase our understanding of underlying pathological events. This information would immediately lead to the implementation of new therapeutic strategies. Research over the last several years has identified extracellular RNAs (exRNA) as a potential source of biomarkers. New technology, such as next generation sequencing (NGS), has made it possible to sensitively and quantitatively assay small amounts of RNA contained in clinically attainable volumes of biofluids such as CSF and blood plasma. In the first two years of this grant, we propose to sequene the exRNA (miRNA and total RNA) from both the CSF and plasma of patients who present with aSAH and the plasma and CSF from premature infants born with IVH. aSAH samples were collected daily~ the volume of sample available will allow us not only to sequence the total RNA including miRNAs, but will permit us to explore unique enrichment strategies in years 3-5 of this grant~ we will examine specific RNAs associated with microvesicles in both CSF and plasma. We have both the daily clinical evaluations of these patients as well as their outcomes (25 subjects in all). We will use these samples to identiy RNA markers that predict onset of vasospasm and the severity of delayed neurological deficits. We also have CSF and plasma samples collected every other day from premature infants with grade III-IV IVH that had reservoirs put in place to evacuate blood and excess CSF. We also have the clinical outcomes from the infants, whether or not they developed hydrocephalus, the need for a permanent shunt, and an 18 month assessment of developmental delays or disabilities. In years 3-5, we will continue to collect samples in collaboration with both of our clinical partners. At that time, we will switch from our discovery platform, the Illumina HiSeq 2000 that has high depth of sequencing coverage, to the Illumina MiSeq for validation. Once the discovery phase is complete and potential biomarkers identified, validation can be carried out on the MiSeq's faster fluidics, imaging, and shortened run times without changing chemistries between the discovery and validation phases.