Journal of neurotrauma
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After spinal cord injury (SCI), a fibrotic scar forms at the injury site that is best characterized by the accumulation of perivascular fibroblasts and deposition of the extracellular matrix protein fibronectin. While fibronectin is a growth-permissive substrate for axons, the fibrotic scar is inhibitory to axon regeneration. The mechanism behind how fibronectin contributes to the inhibitory environment and how the fibronectin matrix is assembled in the fibrotic scar is unknown. ⋯ Assembly of the fibronectin matrix may be mediated by the canonical fibronectin receptor, integrin α5β1, which is primarily expressed by activated macrophages/microglia in the fibrotic scar. Despite the pronounced cavitation after rat SCI, fibrotic scar also is observed in a rat SCI model, which is considered to be more similar to human pathology. Taken together, our study provides insight into the mechanism of fibrotic scar formation after spinal cord injury.
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Journal of neurotrauma · Aug 2015
Female rats demonstrate improved locomotor recovery and greater preservation of white and grey matter following traumatic spinal cord injury compared to males.
The possibility of a gender-related difference in recovery after spinal cord injury (SCI) remains a controversial subject. Current empirical animal research lacks sizable test groups to definitively determine whether significant differences exist. Evaluating locomotor recovery variances between sexes following a precise, clinically relevant spinal cord contusion model can provide valuable insight into a possible gender-related advantage in outcome post-SCI. ⋯ Significant differences in locomotor performance were noticeable as early as 4 weeks post-SCI. Stereological tissue-volume analysis determined that females, more so than males, also exhibited greater volumes of preserved gray and white matter within the injured cord segment as well as more spared ventral white matter area at the center of the lesion. The stereological tissue analysis differences favoring females directly correlated with the female rats' greater functional improvement observed at endpoint.
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Journal of neurotrauma · Aug 2015
Comment LetterLetter to the editor. Commentary regarding the recent publication by Tabarow et al, Functional regeneration of supraspinal connections in a patient with transected spinal cord following transplantation of bulbar olfactory ensheathing cells with peripheral nerve bridging.
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Journal of neurotrauma · Jul 2015
Estimating contact exposure in football using the Head Impact Exposure Estimate (HIEE).
Over the past decade, there has been significant debate regarding the effect of cumulative subconcussive head impacts on short and long-term neurological impairment. This debate remains unresolved, because valid epidemiological estimates of athletes' total contact exposure are lacking. We present a measure to estimate the total hours of contact exposure in football over the majority of an athlete's lifespan. ⋯ The HIEE measure was independent of concussion history (p = 0.82). Estimating total hours of contact exposure may allow for the detection of differences between individuals with variation in subconcussive impacts, regardless of concussion history. This measure is valuable for the surveillance of subconcussive impacts and their associated potential negative effects.
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Journal of neurotrauma · Jul 2015
Distributions of MR Diffusion and Spectroscopy Measures with Traumatic Brain Injury.
Magnetic resonance spectroscopy (MRS) and diffusion tensor imaging (DTI) studies have demonstrated that measures of altered metabolism and axonal injury can be detected following traumatic brain injury. The aim of this study was to characterize and compare the distributions of altered image parameters obtained by these methods in subjects with a range of injury severity and to examine their relative sensitivity for diagnostic imaging in this group of subjects. DTI and volumetric magnetic resonance spectroscopic imaging data were acquired in 40 subjects that had experienced a closed-head traumatic brain injury, with a median of 36 d post-injury. ⋯ The between-group analysis revealed widespread alteration of tissue metabolites that was most strongly characterized by increased choline throughout the cerebrum and cerebellum, reaching as much as 40% increase from control values for the group with the worse cognitive assessment score. In contrast, the between-group comparison of DTI measures revealed only minor differences; however, the Z-score image analysis of individual subject DTI parameters revealed regions of altered values relative to controls throughout the major white matter tracts, but with considerable heterogeneity between subjects and with a smaller extent than the findings for altered metabolite measures. The findings of this study illustrate the complimentary nature of these neuroimaging methods.