Journal of neurotrauma
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Journal of neurotrauma · Nov 2011
Microfluidic generation of haptotactic gradients through 3D collagen gels for enhanced neurite growth.
We adapted a microfluidic system used previously to generate durotactic gradients of stiffness in a 3D collagen gel, to produce haptotactic gradients of adhesive ligands through the collagen gel. Oligopeptide sequences that included bioactive peptide sequences from laminin, YIGSR, or IKVAV, were grafted separately onto type I collagen using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC). Solutions of peptide-grafted collagen and untreated collagen were then used as source and sink input solutions, respectively, in an H-shaped microfluidic network fabricated using traditional soft lithography. ⋯ When these two gradients were presented in combination, the bias in growth acceleration was the largest and most consistent. No differences were observed in the number of neurites choosing to grow up or down the gradients in any condition. These results suggest that the incorporation of distinct gradients of multiple bioactive ligands can improve directional acceleration of regenerating axons.
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Journal of neurotrauma · Nov 2011
Comparative StudyA detailed viscoelastic characterization of the P17 and adult rat brain.
Brain is a morphologically and mechanically heterogeneous organ. Although rat brain is commonly used as an experimental neurophysiological model for various in vivo biomechanical studies, little is known about its regional viscoelastic properties. To address this issue, we have generated viscoelastic mechanical property data for specific anatomical regions of the P17 and adult rat brain. ⋯ All models fit the data equally with no significant differences between them (F-test; p>0.05). The F-test was also used to statistically determine that a Prony series with three time-dependent parameters accurately fit the data with no added benefit from additional terms. The age- and region-dependent rat brain viscoelastic properties presented here will help inform future biomechanical models of the rat brain with specific and accurate regional mechanical property data.
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Journal of neurotrauma · Nov 2011
Case Reports Comparative StudyComparison of acute and chronic traumatic brain injury using semi-automatic multimodal segmentation of MR volumes.
Although neuroimaging is essential for prompt and proper management of traumatic brain injury (TBI), there is a regrettable and acute lack of robust methods for the visualization and assessment of TBI pathophysiology, especially for of the purpose of improving clinical outcome metrics. Until now, the application of automatic segmentation algorithms to TBI in a clinical setting has remained an elusive goal because existing methods have, for the most part, been insufficiently robust to faithfully capture TBI-related changes in brain anatomy. This article introduces and illustrates the combined use of multimodal TBI segmentation and time point comparison using 3D Slicer, a widely-used software environment whose TBI data processing solutions are openly available. ⋯ The proposed tools allow cross-correlation of multimodal metrics from structural imaging (e.g., structural volume, atrophy measurements) with clinical outcome variables and other potential factors predictive of recovery. In addition, the workflows described are suitable for TBI clinical practice and patient monitoring, particularly for assessing damage extent and for the measurement of neuroanatomical change over time. With knowledge of general location, extent, and degree of change, such metrics can be associated with clinical measures and subsequently used to suggest viable treatment options.
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Journal of neurotrauma · Nov 2011
Comparative StudyEngineered in vitro/in silico models to examine neurite target preference.
Research on spinal cord injury (SCI) repair focuses on developing mechanisms to allow neurites to grow past an injury site. In this article, we observe that numerous divergent paths (i.e., spinal roots) are present along the spinal column, and hence guidance strategies must be devised to ensure that regrowing neurites reach viable targets. ⋯ We find in both in silico and in vitro models that the probability of a neurite entering a given root decreases exponentially with respect to the number of roots away from the DRG; consequently, the likelihood of neurites reaching a distant root can be vanishingly small. This result represents a starting point for future strategies to optimize the likelihood that neurites will reach appropriate targets in the regenerating nervous system, and provides a new computational tool to evaluate the feasibility and expected success of neurite guidance in complex geometries.
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Journal of neurotrauma · Nov 2011
ReviewToward a convergence of regenerative medicine, rehabilitation, and neuroprosthetics.
No effective therapeutic interventions exist for severe neural pathologies, despite significant advances in regenerative medicine, rehabilitation, and neuroprosthetics. Our current hypothesis is that a specific combination of tissue engineering, pharmacology, cell replacement, drug delivery, and electrical stimulation, together with plasticity-promoting and locomotor training (neurorehabilitation) is necessary to interact synergistically in order to activate and enable all damaged circuits. ⋯ Therefore, the objective of this review is to highlight the convergent themes, which we believe have a common goal of restoring function after neural damage. The convergent themes discussed in this review include modulation of inflammation and secondary damage, encouraging endogenous repair/regeneration (using scaffolds, cell transplantation, and drug delivery), application of electrical fields to modulate healing and/or activity, and finally modulation of plasticity.