Hyaluronidase reduced edema after experimental traumatic brain injury.

Cerebral edema and the subsequent increased intracranial pressure are associated with mortality and poor outcome following traumatic brain injury. Previous in vitro studies have shown that the Gibbs-Donnan effect, which describes the tendency of a porous, negatively charged matrix to attract positive ions and water, applies to brain tissue and that enzymatic reduction of the fixed charge density can prevent tissue swelling. We tested whether hyaluronidase, an enzyme that degrades the large, negatively charged glycosaminoglycan hyaluronan, could reduce brain edema after traumatic brain injury.

Apolipoprotein E4 impairs spontaneous blood brain barrier repair following traumatic brain injury.

Background: Traumatic Brain Injury (TBI) is a major cause of disability and mortality, to which there is currently no comprehensive treatment. Blood Brain Barrier (BBB) dysfunction is well documented in human TBI patients, yet the molecular mechanisms that underlie this neurovascular unit (NVU) pathology remains unclear. The apolipoprotein-E (apoE) protein has been implicated in controlling BBB integrity in an isoform dependent manner, via suppression of Cyclophilin A (CypA)-Matrix metallopeptidase-9 (MMP-9) signaling cascades, however the contribution of this pathway in TBI-induced BBB permeability is not fully investigated.

The Effect of the APOE4 Gene on Accumulation of Aβ40 After Brain Injury Cannot Be Reversed by Increasing apoE4 Protein.

The apolipoprotein E (apoE) protein is involved in clearance of β-amyloid (Aβ) from the brain; and the APOE4 gene is associated with Aβ plaque formation in humans following traumatic brain injury (TBI). Here, we examined the association between apoE and Aβ after experimental TBI and the effects of APOE alleles on this relationship. We report a biphasic response of soluble apoE protein after TBI with an acute reduction at 1 day postinjury followed by an increase at 7 days postinjury.

Polypathology and dementia after brain trauma: Does brain injury trigger distinct neurodegenerative diseases, or should they be classified together as traumatic encephalopathy?

Neuropathological studies of human traumatic brain injury (TBI) cases have described amyloid plaques acutely after a single severe TBI, and tau pathology after repeat mild TBI (mTBI). This has helped drive the hypothesis that a single moderate to severe TBI increases the risk of developing late-onset Alzheimer's disease (AD), while repeat mTBI increases the risk of developing chronic traumatic encephalopathy (CTE). In this review we critically assess this position-examining epidemiological and case control human studies, neuropathological evidence, and preclinical data.

Apolipoprotein E Regulates Injury-Induced Activation of Hippocampal Neural Stem and Progenitor Cells.

Partial recovery from even severe traumatic brain injury (TBI) is ubiquitous and occurs largely through unknown mechanisms. Recent evidence suggests that hippocampal neural stem/progenitor cell (NSPC) activation and subsequent neurogenesis are responsible for at least some aspects of spontaneous recovery following TBI. Apolipoprotein E (ApoE) regulates postnatal neurogenesis in the hippocampus and is therefore a putative mediator of injury-induced neurogenesis.

Injury-Induced Neurogenesis: Mechanisms and Relevance.

Partial recovery from brain injury due to trauma, hypoxia, or stroke, is ubiquitous and occurs largely through unknown mechanisms. It is now well accepted that injury enhances proliferation of quiescent stem and progenitor cells in specialized niches within the brain. However, whether this injury-induced neurogenesis contributes to recovery after brain injury remains controversial.

Experimental traumatic brain injury induces rapid aggregation and oligomerization of amyloid-beta in an Alzheimer's disease mouse model.

Soluble amyloid-beta (Aβ) oligomers are hypothesized to be the pathogenic species in Alzheimer's disease (AD), and increased levels of oligomers in the brain subsequent to traumatic brain injury (TBI) may exacerbate secondary injury pathways and underlie increased risk of developing AD in later life. To determine whether TBI causes Aβ aggregation and oligomerization in the brain, we exposed triple transgenic AD model mice to controlled cortical impact injury and measured levels of soluble, insoluble, and oligomeric Aβ by enzyme-linked immunosorbent assay (ELISA) at 1, 3, and 7 days postinjury. TBI rapidly increased levels of both soluble and insoluble Aβ40 and Aβ42 in the injured cortex at 1 day postinjury.

It's money! Real-world grant experience through a student-run, peer-reviewed program.

Grantsmanship is an integral component of surviving and thriving in academic science, especially in the current funding climate. Therefore, any additional opportunities to write, read, and review grants during graduate school may have lasting benefits on one's career. We present here our experience with a small, student-run grant program at Georgetown University Medical Center.

Controlled cortical impact results in an extensive loss of dendritic spines that is not mediated by injury-induced amyloid-beta accumulation.

The clinical manifestations that occur after traumatic brain injury (TBI) include a wide range of cognitive, emotional, and behavioral deficits. The loss of excitatory synapses could potentially explain why such diverse symptoms occur after TBI, and a recent preclinical study has demonstrated a loss of dendritic spines, the postsynaptic site of the excitatory synapse, after fluid percussion injury. The objective of this study was to determine if controlled cortical impact (CCI) also resulted in dendritic spine retraction and to probe the underlying mechanisms of this spine loss.

The effect of injury severity on behavior: a phenotypic study of cognitive and emotional deficits after mild, moderate, and severe controlled cortical impact injury in mice.

Traumatic brain injury (TBI) can cause a broad array of behavioral problems including cognitive and emotional deficits. Human studies comparing neurobehavioral outcomes after TBI suggest that cognitive impairments increase with injury severity, but emotional problems such as anxiety and depression do not. To determine whether cognitive and emotional impairments increase as a function of injury severity we exposed mice to sham, mild, moderate, or severe controlled cortical impact (CCI) and evaluated performance on a variety of neurobehavioral tests in the same animals before assessing lesion volume as a histological measure of injury severity.

Delayed inflammatory mRNA and protein expression after spinal cord injury.

Background: Spinal cord injury (SCI) induces secondary tissue damage that is associated with inflammation. We have previously demonstrated that inflammation-related gene expression after SCI occurs in two waves - an initial cluster that is acutely and transiently up-regulated within 24 hours, and a more delayed cluster that peaks between 72 hours and 7 days. Here we extend the microarray analysis of these gene clusters up to 6 months post-SCI.

Modulation of ABCA1 by an LXR agonist reduces β-amyloid levels and improves outcome after traumatic brain injury.

Traumatic brain injury (TBI) increases brain beta-amyloid (Aβ) in humans and animals. Although the role of Aβ in the injury cascade is unknown, multiple preclinical studies have demonstrated a correlation between reduced Aβ and improved outcome. Therefore, therapeutic strategies that enhance Aβ clearance may be beneficial after TBI.