Journal of neurotrauma
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Polyamines spermine and spermidine are highly regulated, ubiquitous aliphatic cations that maintain DNA structure and function as immunomodulators and as antioxidants. Polyamine homeostasis is disrupted after brain injuries, with concomitant generation of toxic metabolites that may contribute to secondary injuries. To test the hypothesis of increased brain polyamine catabolism after traumatic brain injury (TBI), we determined changes in catabolic enzymes and polyamine levels in the rat brain after lateral controlled cortical impact TBI. ⋯ Interestingly, bilateral increases in cortical SSAT-ir neurons occurred at 72 h post-injury, whereas hippocampal changes occurred only ipsilaterally. Prolonged increases in brain polyamine catabolism are the likely cause of loss of homeostasis in this pathway. The potential for simple therapeutic interventions (e.g., polyamine supplementation or inhibition of polyamine oxidation) is an exciting implication of these studies.
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Journal of neurotrauma · Mar 2010
In situ detection of inflammatory mediators in post mortem human brain tissue after traumatic injury.
Little is known about the molecular events following severe traumatic brain injury (TBI) in humans and to date there are no efficient therapies for the treatment of patients. In this study, the first of its kind in human tissue, a total of 21 post mortem trauma brain samples were analyzed. The inflammatory response within the brain tissue was explored by measuring the expression of various inflammatory cytokines at the mRNA and protein levels. ⋯ This study shows for the first time in human brain tissue that 1) pro-inflammatory mediator protein levels are significantly increased in situ following acute brain injury while anti-inflammatory cytokines protein levels remain unchanged; 2) the cerebral inflammatory response begins within minutes of acute TBI, much earlier than previously thought; 3) IL-6, IL-8, TNF-alpha, and IL-1beta mRNA levels are significantly increased following injury; 4) the rise in cytokine protein level coincides with increased levels of their mRNAs suggesting that traumatic injury elicits an immediate cerebral inflammatory response. Altogether these data confirm and extend previous observations on the release of cytokines in the cerebrospinal fluid of severe TBI patients. Finally, this study highlights the need to characterize the cell source of cytokines and elucidate their mode of action.
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Journal of neurotrauma · Mar 2010
Vascular endothelial growth factor is involved in mediating increased de novo hippocampal neurogenesis in response to traumatic brain injury.
Stimulating the endogenous repair process after traumatic brain injury (TBI) can be an important approach in neuroregenerative medicine. Vascular endothelial growth factor (VEGF) is one of the molecules that can increase de novo hippocampal neurogenesis. Here, we tested whether VEGF signaling through Flk1 (VEGF receptor 2) is involved in the neurogenic process after experimental TBI. ⋯ We found that VEGF infusion significantly increased the number of BrdU+/Prox1+ new neurons, decreased the number of TUNEL+ cells, but did not change the number of BrdU+ newborn cells per se. Infusion with SU5416 caused no significant changes. Our results suggest that (a) VEGF is a part of the molecular signaling network that mediates de novo hippocampal neurogenesis after TBI; (b) VEGF predominantly mediates survival of de novo granule neurons rather than proliferation of neuroblasts in the injured brain; and (c) additional VEGF receptor(s) and/or other molecular mechanism(s) are also involved in mediating increased neurogenesis following injury.
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Journal of neurotrauma · Mar 2010
Post-traumatic interpeduncular cistern hemorrhage as a marker for brainstem lesions.
We retrospectively reviewed a prospectively collected database of our diffuse axonal injury (DAI) patients to evaluate the accuracy of the evidence of interpeduncular cistern (IPC) blood on computed tomography (CT) scan when diagnosing brainstem lesions (BSL) early after trauma. From December 1989 to December 2008 we prospectively maintained a clinical and radiological database of head injured patients admitted to our neurosurgical intensive care unit (ICU) that met the following criteria: coma (Glasgow Coma Scale [GCS] score < 9) following the traumatic event; neurological derangement not ascribable to hypoxia, hypotension, or long-acting drugs able to alter state of consciousness; absence of lesions accounting for the severity of coma either on the admission CT scan or on subsequent CT scans; and no contraindications to magnetic resonance imaging (MRI; e.g., indwelling metallic implants). ⋯ The evidence of IPC blood on CT scan as an indicator of BSL had a sensitivity of 0.78 (95% CI: 0.70, 0.86), and a specificity of 0.80 (95% CI: 0.72, 0.88), with a 3.90 likelihood ratio for a positive CT scan, and a 0.28 likelihood ratio for a negative CT scan. Our data suggest that the finding of IPC blood on CT scan early after trauma in patients with otherwise unexplained coma is a good marker for possible brainstem lesions.
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The objective of this study was to estimate the independent association of sex with outcome after mild traumatic brain injury (mTBI). We performed an analysis of a subset of an established cohort involving 1425 mTBI patients presenting to an academic emergency department (ED). The associations between sex and three outcomes determined 3 months after the initial ED visit were examined: post-concussive symptom (PCS) score (0, 1-5, 6-16, and >16), the number of days to return of normal activities (0, 1-7, and >7), and the number of days of work missed (0, 1-7,and >7). ⋯ Female sex is associated with significantly higher odds of poor outcome after mTBI, as measured by PCS score, after control for appropriate confounders. The observed pattern of peak disability for females during the child-bearing years suggests disruption of endogenous estrogen or progesterone production. Attempts to better understand how mTBI affects production of these hormones acutely after injury and during the recovery period may shed light on the mechanism behind poorer outcome among females and putative therapeutic interventions.