Biologic Transplantation and Neurotrophin-Induced Neuroplasticity After Traumatic Brain Injury

Microstructure and Genetic Polymorphisms: Role in Motor Rehabilitation After Subcortical Stroke

Background and Purpose: Motor deficits are the most common disability after stroke, and early prediction of motor outcomes is critical for guiding the choice of early interventions. Two main factors that may impact the response to rehabilitation are variations in the microstructure of the affected corticospinal tract (CST) and genetic polymorphisms in brain-derived neurotrophic factor (BDNF). The purpose of this article was to review the role of these factors in stroke recovery, which will be useful for constructing a predictive model of rehabilitation outcomes.

Summary of Review: We review the microstructure of the CST, including its origins in the primary motor area (M1), primary sensory area (S1), premotor cortex (PMC), and supplementary motor area (SMA). Damage to these fibers is disease-causing and can directly affect rehabilitation after subcortical stroke. BDNF polymorphisms are not disease-causing but can indirectly affect neuroplasticity and thus motor recovery. Both factors are known to be correlated with motor recovery. Further work is needed using large longitudinal patient samples and animal experiments to better establish the role of these two factors in stroke rehabilitation.

Conclusions: Microstructure and genetic polymorphisms should be considered possible predictors or covariates in studies investigating motor recovery after subcortical stroke. Future predictive models of stroke recovery will likely include a combination of structural and genetic factors to allow precise individualization of stroke rehabilitation strategies.

Restoration of olfactory dysfunctions by nanomaterials and stem cells-based therapies: Current status and future perspectives

Dysfunction in the olfactory system of a person can have adverse effects on their health and quality of life. It can even increase mortality among individuals. Olfactory dysfunction is related to many factors, including post-viral upper respiratory infection, head trauma, and neurodegenerative disorders. Although some clinical therapies such as steroids and olfactory training are already available, their effectiveness is limited and controversial. Recent research in the field of therapeutic nanoparticles and stem cells has shown the regeneration of dysfunctional olfactory systems. Thus, we are motivated to highlight these regenerative approaches. For this, we first introduce the anatomical characteristics of the olfactory pathway, then detail various pathological factors related to olfactory dysfunctions and current treatments, and then finally discuss the recent regenerative endeavors, with particular focus on nanoparticle-based drug delivery systems and stem cells. This review offers insights into the development of future therapeutic approaches to restore and regenerate dysfunctional olfactory systems.

Extracellular Vesicles, Stem Cells and the Role of miRNAs in Neurodegeneration

There are different modalities of intercellular communication governed by cellular homeostasis. In this review, we will explore one of these forms of communication called extracellular vesicles (EVs). These vesicles are released by all cells in the body and are heterogeneous in nature. The primary function of EVs is to share information through their cargo consisting of proteins, lipids and nucleic acids (mRNA, miRNA, dsDNA etc.) with other cells, which have a direct consequence on their microenvironment. We will focus on the role of EVs of mesenchymal stem cells (MSCs) in the nervous system and how these participate in intercellular communication to maintain physiological function and provide neuroprotection. However, deregulation of this same communication system could play a role in several neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, Amyotrophic lateral sclerosis, multiple sclerosis, prion disease and Huntington's disease. The release of EVs from a cell provides crucial information to what is happening inside the cell and thus could be used in diagnostics and therapy. We will discuss and explore new avenues for the clinical applications of using engineered MSC-EVs and their potential therapeutic benefit in treating neurodegenerative diseases.

Cell-Biological Requirements for the Generation of Dentate Gyrus Granule Neurons

The dentate gyrus (DG) receives highly processed information from the associative cortices functionally integrated in the trisynaptic hippocampal circuit, which contributes to the formation of new episodic memories and the spontaneous exploration of novel environments. Remarkably, the DG is the only brain region currently known to have high rates of neurogenesis in adults (Andersen et al., 1966, 1971). The DG is involved in several neurodegenerative disorders, including clinical dementia, schizophrenia, depression, bipolar disorder and temporal lobe epilepsy. The principal neurons of the DG are the granule cells. DG granule cells generated in culture would be an ideal model to investigate their normal development and the causes of the pathologies in which they are involved and as well as possible therapies. Essential to establish such in vitro models is the precise definition of the most important cell-biological requirements for the differentiation of DG granule cells. This requires a deeper understanding of the precise molecular and functional attributes of the DG granule cells in vivo as well as the DG cells derived in vitro. In this review we outline the neuroanatomical, molecular and cell-biological components of the granule cell differentiation pathway, including some growth- and transcription factors essential for their development. We summarize the functional characteristics of DG granule neurons, including the electrophysiological features of immature and mature granule cells and the axonal pathfinding characteristics of DG neurons. Additionally, we discuss landmark studies on the generation of dorsal telencephalic precursors from pluripotent stem cells (PSCs) as well as DG neuron differentiation in culture. Finally, we provide an outlook and comment critical aspects.

Comparisons of the therapeutic effects of three different routes of bone marrow mesenchymal stem cell transplantation in cerebral ischemic rats

Bone marrow mesenchymal stem cells (BMSCs) are mainly administered via three routes: intra-arterial, intravenous and intracerebral. It has been reported that BMSC administration via each route ameliorates the functional deficits after cerebral ischemia. However, there have been no comparisons of the therapeutic benefits of BMSC administration through different delivery routes. In this study, we injected BMSCs into a rat model of transient middle cerebral artery occlusion (MCAO) through the intra-arterial, intravenous, or intracerebral route at day 7 after MCAO. Control animals received only the vehicle. Neurological function was assessed at post-ischemic days (PIDs) 1, 7, 14, 21, 28 and 35 using behavioral tests (modified Neurological Severity Score (mNSS) and the adhesive removal test). At PID 35, the rat brain tissues were processed for histochemical and immunohistochemical staining. Our results showed that BMSC transplantation via the intra-arterial, intravenous, and intracerebral routes induced greater improvement in neurological functions than the control treatments; furthermore, the intra-arterial route showed the greatest degree and speed of neurological functional recovery. Moreover, BMSCs treatment through each route enhanced reconstruction of axonal myelination in the area of the corpus callosum on the infarct side of the cerebral hemisphere, increased the expression of SYN and Ki-67, and decreased the expression of Nogo-A in the brain. These effects were more apparent in the intra-arterial group than in the intravenous and intracerebral groups. These data suggest that BMSCs transplantation, especially through intra-arterial delivery, can effectively improve neurological function intra-arterial. The underlying mechanism may include the promotion of synaptogenesis, endogenous cell proliferation, and axonal regeneration.

Time-dependent role of prefrontal cortex and hippocampus on cognitive improvement by aripiprazole in olfactory bulbectomized mice

Dopamine (DA) modulates cognitive functions in the prefrontal cortex (PFC) and hippocampus. Olfactory bulbectomy (OBX) in mice induces cognitive dysfunctions. Recently, we reported that aripiprazole (ARI) normalizes the behavioral hyper-responsivity to DA agonists in OBX mice. However, it remains unclear whether ARI affects OBX-induced cognitive dysfunctions. To address this question we evaluated ARI-treated and untreated OBX mice in a passive avoidance test. Then, we investigated the effects of ARI on cell proliferation in the hippocampal dentate gyrus by immunohistochemistry, and on c-fos levels in the PFC and hippocampus, as well as nerve growth factor (NGF) levels in the hippocampus by western blotting. On the 14th day after surgery OBX mice showed an alteration in passive avoidance and decreases in both cell proliferation and levels of p-ERK, p-CREB and NGF in the hippocampus. The cognitive dysfunctions in OBX mice improved 30min to 24h after the administration of ARI (0.01mg/kg). C-fos levels in the PFC but not in the hippocampus was increased 30min after the administration (early response). This early response was inhibited by the selective D₁ receptor antagonist SCH23390. Cell proliferation and NGF levels in the hippocampus increased 24h after ARI administration (late response), and these effects were also inhibited by SCH23390. The MEK1/2 inhibitor U0126 prevented ARI from improving the behavioral impairment as well as enhancing NGF levels in OBX mice. These findings revealed the potential of ARI to improve cognitive dysfunctions via D₁ receptors with the PFC and hippocampus being affected sequentially.

The effect of rat bone marrow derived mesenchymal stem cells transplantation for restoration of olfactory disorder

The purpose of the study was to investigate the effect of bone marrow-derived mesenchymal stem cells (BMSCs) transplantation on olfactory epithelium (OE) of morphologic and functional restoration following neural Sensorineural Disorder in rats. Except the Normal group, twenty-one rats underwent Triton X-100 (TX-100) irrigation to induce degeneration of OE, and then BMSCs and PBS were treated from the both medial canthus to the rear part of the both nasal cavity into the experimental group and then were observed for restoration according to time point. At two and four weeks after transplantation with BMSCs, restoration of OE was observed with olfactory marker protein (OMP) and behavioral test. And we observed the expression of OMP, nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF). After TX-100 irrigation, the OE almost disappeared in 3 days. At four weeks after transplantation with BMSCs, the thickness and cellular composition of OE was considerably restored to normal group and expression of OMP was markedly increased when compared with PBS group and reduced the searching time in the behavioral test. Furthermore at two weeks after treatment with BMSCs, expression of NGF and BDNF was greatly increased when compared with PBS group. However at four weeks after treatment with BMSCs, expression of NGF and BDNF was slightly decreased. Our results suggest the BMSCs transplantation affect restoration of OE and olfaction, most likely via regulation of the neurotrophic factor expression, especially the expression of NGF and BDNF and has a possibility of a new therapeutic strategy for the treatment of olfactory disorder caused by the degeneration of OE.

Transplantation of human umbilical cord blood mesenchymal stem cells to treat a rat model of traumatic brain injury

In the present study, human umbilical cord blood mesenchymal stem cells were injected into a rat model of traumatic brain injury via the tail vein. Results showed that 5-bromodeoxyuridine-labeled cells aggregated around the injury site, surviving up to 4 weeks post-transplantation. In addition, transplantation-related death did not occur, and neurological functions significantly improved. Histological detection revealed attenuated pathological injury in rat brain tissues following human umbilical cord blood mesenchymal stem cell transplantation. In addition, the number of apoptotic cells decreased. Immunohistochemistry and in situ hybridization showed increased expression of brain-derived neurotrophic factor, nerve growth factor, basic fibroblast growth factor, and vascular endothelial growth factor, along with increased microvessel density in surrounding areas of brain injury. Results demonstrated migration of transplanted human umbilical cord blood mesenchymal stem cells into the lesioned boundary zone of rats, as well as increased angiogenesis and expression of related neurotrophic factors in the lesioned boundary zone.

Suppression of neurocan and enhancement of axonal density in rats after treatment of traumatic brain injury with scaffolds impregnated with bone marrow stromal cells

OBJECT

Neurocan is a major form of growth-inhibitory molecule (growth-IM) that suppresses axonal regeneration after neural injury. Bone marrow stromal cells (MSCs) have been shown to inhibit neurocan expression in vitro and in animal models of cerebral ischemia. Therefore, the present study was designed to investigate the effects of treatment of MSCs impregnated with collagen scaffolds on neurocan expression after traumatic brain injury (TBI).

METHODS

Adult male Wistar rats were injured with controlled cortical impact and treated with saline, human MSCs (hMSCs) (3 × 10(6)) alone, or hMSCs (3 × 10(6)) impregnated into collagen scaffolds (scaffold + hMSCs) transplanted into the lesion cavity 7 days after TBI (20 rats per group). Rats were sacrificed 14 days after TBI, and brain tissues were harvested for immunohistochemical studies, Western blot analyses, laser capture microdissections, and quantitative real-time reverse transcriptase polymerase chain reaction (qRT-PCR) to evaluate neurocan protein and gene expressions after various treatments.

RESULTS

Animals treated with scaffold + hMSCs after TBI showed increased axonal and synaptic densities compared with the other groups. Scaffold + hMSC treatment was associated with reduced TBI-induced neurocan protein expression and upregulated growth-associated protein 43 (GAP-43) and synaptophysin expression in the lesion boundary zone. In addition, animals in the scaffold + hMSC group had decreased neurocan transcription in reactive astrocytes after TBI. Reduction of neurocan expression was significantly greater in the scaffold + hMSC group than in the group treated with hMSCs alone.

CONCLUSIONS

The results of this study show that transplanting hMSCs with scaffolds enhances the effect of hMSCs on axonal plasticity in TBI rats. This enhanced axonal plasticity may partially be attributed to the downregulation of neurocan expression by hMSC treatment after injury.

Down-regulation of Nogo-A by collagen scaffolds impregnated with bone marrow stromal cell treatment after traumatic brain injury promotes axonal regeneration in rats

Nogo-A is a major form of growth inhibitory molecule (growth-IM) which inhibits axonal regeneration and neurite regrowth after neural injury. Bone marrow stromal cells (MSCs) have been shown to inhibit Nogo-A expression in vitro and in cerebral ischemic animal models. The present study was designed to investigate the effects of treatment with human MSCs (hMSCs) impregnated into collagen scaffolds on the expression of Nogo-A and axonal plasticity after traumatic brain injury (TBI). Adult male Wistar rats were injured with controlled cortical impact and treated either with saline, hMSCs-alone or hMSCs impregnated into collagen scaffolds (scaffold+hMSC) transplanted into the lesion cavity 7 days after TBI. Rats were sacrificed 14 days after TBI and brain tissues were harvested for immunohistochemical studies, Western blot analysis, laser capture microdissections and qRT-PCR to evaluate axonal density and Nogo-A protein and gene expressions. Our data showed that treatment of TBI with scaffold+hMSC significantly decreased TBI-induced Nogo-A protein expression and increased axonal density compared to saline and hMSC-alone treatments. In addition, scaffold+hMSC transplantation decreased Nogo-A transcription in oligodendrocytes after TBI. Scaffold+hMSC treatment was superior to hMSC-alone treatment in suppressing Nogo-A expression and enhancing axonal regeneration after TBI. Our data suggest that transplanting hMSCs with scaffolds down-regulates Nogo-A transcription and protein expression which may partially contribute to the enhanced axonal regeneration after TBI.

Improvement in functional recovery with administration of Cerebrolysin after experimental closed head injury

OBJECT

Cerebrolysin is a unique peptide preparation that mimics the action of neurotrophic factors. This study was designed to investigate the effects of acute treatment of experimental closed head injury (CHI) in rats with Cerebrolysin on neurological function.

METHODS

Adult male Wistar rats (n = 60) were subjected to impact acceleration-induced CHI. Closed head injured rats received intraperitoneal injection of saline (n = 30) or Cerebrolysin (2.5 ml/kg, n = 30) starting 1 hour postinjury and administered once daily until they were killed (2 or 14 days after CHI). To evaluate functional outcome, the modified neurological severity score (mNSS), foot fault, adhesive removal, and Morris water maze (MWM) tests were performed. Animals were killed on Day 14 (n = 20) after injury, and their brains were removed and processed for measurement of neuronal cells, axonal damage, apoptosis, and neuroblasts. The remaining rats (n = 40) were killed 2 days postinjury to evaluate cerebral microvascular patency by fluorescein isothiocyanate (FITC)-dextran perfusion (n = 16) and to measure the expression of vascular endothelial growth factor (VEGF) and matrix metalloproteinase-9 (MMP-9) by using real-time reverse transcriptase-polymerase chain reaction (RT-PCR, n = 8) and by immunohistochemical analysis (n = 16).

RESULTS

At 14 days post-CHI, the Cerebrolysin treatment group exhibited significant improvements in functional outcomes (the adhesive removal, mNSS, foot-fault, and MWM tests), and significantly more neurons and neuroblasts were present in the dentate gyrus (DG) (p < 0.05) compared with the saline-treated group (p < 0.05). At 2 days post-CHI, the Cerebrolysin group exhibited a significantly higher percentage of phosphorylated neurofilament H (pNF-H)-positive staining area in the striatum (p < 0.05), a significant increase in the percentage of FITC-dextran perfused vessels in the brain cortex (p < 0.05), a significant increase in the number of VEGF-positive cells (p < 0.05), and a significant reduction in the MMP-9 staining area (p < 0.05) compared with the saline-treated group. There was no significant difference in mRNA levels of MMP-9 and VEGF in the hippocampus and cortex 48 hours postinjury between Cerebrolysin- and saline-treated rats that sustained CHI.

CONCLUSIONS

Acute Cerebrolysin treatment improves functional recovery in rats after CHI. Cerebrolysin is neuroprotective for CHI (increased neurons in the dentate gyrus and the CA3 regions of the hippocampus and increased neuroblasts in the dentate gyrus) and may preserve axonal integrity in the striatum (significantly increased percentage of pNF-H-positive tissue in the striatum). Reduction of MMP-9 and elevation of VEGF likely contribute to enhancement of vascular patency and integrity as well as neuronal survival induced by Cerebrolysin. These promising results suggest that Cerebrolysin may be a useful treatment in improving the recovery of patients with CHI.

Effects of treating traumatic brain injury with collagen scaffolds and human bone marrow stromal cells on sprouting of corticospinal tract axons into the denervated side of the spinal cord

OBJECT

This study was designed to investigate how transplantation into injured brain of human bone marrow stromal cells (hMSCs) impregnated in collagen scaffolds affects axonal sprouting in the spinal cord after traumatic brain injury (TBI) in rats. Also investigated was the relationship of axonal sprouting to sensorimotor functional recovery after treatment.

METHODS

Adult male Wistar rats (n = 24) underwent a controlled cortical impact injury and were divided into three equal groups (8 rats/group). The two treatment groups received either hMSCs (3 × 10(6)) alone or hMSC (3 × 10(6))-impregnated collagen scaffolds transplanted into the lesion cavity. In the control group, saline was injected into the lesion cavity. All treatments were performed 7 days after TBI. On Day 21 after TBI, a 10% solution of biotinylated dextran amine (10,000 MW) was stereotactically injected into the contralateral motor cortex to label the corticospinal tract (CST) originating from this area. Sensorimotor function was tested using the modified neurological severity score (mNSS) and foot-fault tests performed on Days 1, 7, 14, 21, 28, and 35 after TBI. Spatial learning was tested with Morris water maze test on Days 31-35 after TBI. All rats were sacrificed on Day 35 after TBI, and brain and spinal cord (cervical and lumbar) sections were stained immunohistochemically for histological analysis.

RESULTS

Few biotinylated dextran amine-labeled CST fibers crossing over the midline were found in the contralateral spinal cord transverse sections at both cervical and lumbar levels in saline-treated (control) rats. However, hMSC-alone treatment significantly increased axonal sprouting from the intact CST into the denervated side of the gray matter of both cervical and lumbar levels of the spinal cord (p < 0.05). Also, this axonal sprouting was significantly more in the scaffold+hMSC group compared with the hMSC-alone group (p < 0.05). Sensorimotor functional analysis showed significant improvement of mNSS (p < 0.05) and foot-fault tests (p < 0.05) in hMSC-alone and scaffold+hMSC-treated rats compared with controls (p < 0.05). Functional improvement, however, was significantly greater in the scaffold+hMSC group compared with the hMSC-alone group (p < 0.05). Morris water maze testing also showed significant improvement in spatial learning in scaffold+hMSC and hMSC-alone groups compared with the control group (p < 0.05), with rats in the scaffold+hMSC group performing significantly better than those in the hMSC-alone group (p < 0.05). Pearson correlation data showed significant correlation between the number of crossing CST fibers detected and sensorimotor recovery (p < 0.05).

CONCLUSIONS

Axonal plasticity plays an important role in neurorestoration after TBI. Transplanting hMSCs with scaffolds enhances the effect of hMSCs on axonal sprouting of CST fibers from the contralateral intact cortex into the denervated side of spinal cord after TBI. This enhanced axonal regeneration may at least partially contribute to the therapeutic benefits of treating TBI with hMSCs.

MRI evaluation of axonal reorganization after bone marrow stromal cell treatment of traumatic brain injury

We treated traumatic brain injury (TBI) with human bone marrow stromal cells (hMSCs) and evaluated the effect of treatment on white matter reorganization using MRI. We subjected male Wistar rats (n = 17) to controlled cortical impact and either withheld treatment (controls; n = 9) or inserted collagen scaffolds containing hMSCs (n = 8). Six weeks later, the rats were sacrificed and MRI revealed selective migration of grafted neural progenitor cells towards the white matter reorganized boundary of the TBI-induced lesion. Histology confirmed that the white matter had been reorganized, associated with increased fractional anisotropy (FA; p < 0.01) in the recovery regions relative to the injured core region in both treated and control groups. Treatment with hMSCs increased FA in the recovery regions, lowered T(2) in the core region, decreased lesion volume and improved functional recovery relative to untreated controls. Immunoreactive staining showed axonal projections emanating from neurons and extruding from the corpus callosum into the ipsilateral cortex at the boundary of the lesion. Fiber tracking (FT) maps derived from diffusion tensor imaging confirmed the immunohistological data and provided information on axonal rewiring. The apparent kurtosis coefficient (AKC) detected additional axonal remodeling regions with crossing axons, confirmed by immunohistological staining, compared with FA. Our data demonstrate that AKC, FA, FT and T(2) can be used to evaluate treatment-induced white matter recovery, which may facilitate restorative therapy in patients with TBI.

Treatment of TBI with collagen scaffolds and human marrow stromal cells increases the expression of tissue plasminogen activator

This study examines the effects of combination therapy of collagen scaffolds and human marrow stromal cells (hMSCs) on the expression of tissue plasminogen activator (tPA) after traumatic brain injury (TBI) in rats. Adult male Wistar rats (n=48) were injured with controlled cortical impact and treated either with scaffolds suffused with hMSCs (3×10(6)) or hMSCs (3×10(6)) alone transplanted into the lesion cavity 1 week after TBI. A control group was treated with saline. Neurological function was assessed using the Morris Water Maze test (MWM) and modified Neurological Severity Scores (mNSS). The rats were sacrificed 14 days after TBI and brain samples were processed for immunohistochemical analysis and quantitative Western blot and quantitative real-time polymerase chain reaction (qRT-PCR) studies. Enhanced functional improvement was observed on both the mNSS and MWM tests in the scaffold+hMSC-treated group compared to the other two groups. Immunostaining with anti-human mitochondrial antibody (E5204) showed more hMSCs in the injury zone of the scaffold+hMSC group compared to the hMSC-alone group. Triple staining showed that more neurons were tPA-positive in the scaffold+hMSC group compared to the other two groups (p<0.05). Western blot analysis and qRT-PCR showed that scaffold+hMSC and hMSC-alone treatment enhanced the expression of tPA compared to controls (p<0.05), but tPA expression was significantly greater in the scaffold+hMSC group. The induction of tPA by hMSCs after TBI may be one of the mechanisms involved in promoting functional improvement after TBI.

Treatment of traumatic brain injury in mice with bone marrow stromal cell-impregnated collagen scaffolds

OBJECT

This study was designed to investigate new ways of delivering human marrow stromal cells (hMSCs) to the injured brain by impregnating them into collagen scaffolds in a mouse model of traumatic brain injury (TBI).

METHODS

Eight C57BL/6 J mice were injured with controlled cortical impact and received transplantation into the lesion cavity of 0.3 x 10(6) hMSCs impregnated into 3D porous collagen scaffolds. Additional experimental groups of 8 mice each received scaffolds implanted alone into the lesion cavity, hMSCs administered alone intracerebrally or intravenously, or saline injected into the lesion core. All treatments were performed 7 days after TBI. Spatial learning was measured using a modified Morris water maze test, and brain tissue samples were processed for histopathological analysis.

RESULTS

The results showed that hMSC-impregnated scaffolds were more effective than hMSCs administered alone (either intravenously or intracerebrally) in improving spatial learning, reducing lesion volume, and increasing vascular density after TBI.

CONCLUSIONS

Collagen scaffolds populated with hMSCs may be a new way to reconstruct injured brain tissue and improve neurological function after TBI.

Long-lasting benefits after treatment of traumatic brain injury (TBI) in rats with combination therapy of marrow stromal cells (MSCs) and simvastatin

This study was designed to investigate the beneficial effects of combination therapy of simvastatin and marrow stromal cells (MSCs) in improving functional outcome after traumatic brain injury (TBI) in rats. Adult female Wistar rats (n=72 and 8, per group) were injured with controlled cortical impact and treated either with monotherapy of MSCs or simvastatin or a combination therapy of these two agents. Different combination doses were tested, and nine groups of animals were studied. Neurological function was evaluated using Modified Neurological Severity Score (MNSS), and animals were sacrificed 3 months after injury. Coronal brain sections were stained with standard hematoxylin and eosin immunohistochemistry. Our results showed that, though functional improvement was seen with monotherapies of MSCs and simvastatin, the combination therapy when used in optimal doses was significantly better in improving functional outcome. This improvement was long lasting and persisted until the end of the trial (3 months). The optimum combination dose was 0.5mg of simvastatin combined with 2 x 10(6) MSCs. Post mortem analysis showed the presence of donor MSCs within the injured cortex. Endogenous cellular proliferation induced by the neurorestorative treatments was also observed in the lesion boundary zone. Our data show that MSCs and simvastatin have a synergistic effect in improving functional outcome after TBI.

Delayed transplantation of human marrow stromal cell-seeded scaffolds increases transcallosal neural fiber length, angiogenesis, and hippocampal neuronal survival and improves functional outcome after traumatic brain injury in rats

Traumatic brain injury (TBI) is a major cause of death and disability worldwide; however, no effective treatment has been clinically identified. Our recent studies show that the combination of collagen scaffolds with human bone morrow stromal cells (hMSCs) for treatment of TBI improves functional outcome and reduces the lesion volume when this combination was applied at day 4 after TBI in rats. The mechanisms underlying these benefits remain unclear. Whether further delayed treatment with this combination will provide benefits has not been investigated. In the present study, we investigated whether the delayed (7 days post injury) transplantation would have beneficial effects on functional and histological outcome and sought to elucidate underlying mechanisms of therapeutic action. Collagen scaffolds seeded with 3 x 10(6) hMSCs, scaffolds alone, 3 x 10(6) hMSCs alone, or saline were transplanted into the lesion cavity of the injured cortex 7 days after TBI. Sensorimotor function and spatial learning were measured. Corticocortical labeling with 1, 1''-dioleyl-3, 3, 3'', 3''-tetramethylindocarbocyanine methanesulfonate (DiI) was performed at day 36 after TBI. The rats were sacrificed 43 days after TBI, and the brain tissue was processed for DiI-labeling fiber and immunohistochemical analyses. The present data show that delayed transplantation of hMSCs or scaffolds seeded with hMSCs improved spatial learning and sensorimotor function, enhanced angiogenesis in the injured cortex and the ipsilateral hippocampus and increased DiI-labeled neural fiber length in the injured cortex. hMSC-seeded scaffolds may be a new and effective way to improve neurological function after TBI.

Traumatic brain injury research priorities: the Conemaugh International Brain Injury Symposium

In 2005, an international symposium was convened with over 100 neuroscientists from 13 countries and major research centers to review current research in traumatic brain injury (TBI) and develop a consensus document on research issues and priorities. Four levels of TBI research were the focus of the discussion: basic science, acute care, post-acute neurorehabilitation, and improving quality of life (QOL). Each working group or committee was charged with reviewing current research, discussion and prioritizing future research directions, identifying critical issues that impede research in brain injury, and establishing a research agenda that will drive research over the next five years, leading to significantly improved outcomes and QOL for individuals suffering brain injuries. This symposium was organized at the request of the Congressional Brain Injury Task Force, to follow up on the National Institutes of Health Consensus Conference on TBI as mandated by the TBI ACT of 1996. The goal was to review what progress had been made since the National Institutes of Health (NIH) Consensus Conference, and also to follow up on the 1990's Decade of the Brain Project. The major purpose of the symposium was to provide recommendations to the U.S. Congress on a priority basis for research, treatment, and training in TBI over the next five years.

Treatment of traumatic brain injury in mice with marrow stromal cells

This study was designed to investigate the potential beneficial effects of bone marrow stromal cell (MSC) treatment of traumatic brain injury (TBI) in mice. Twelve female C57BL/6J mice (weight, 21-26 g) were injured with controlled cortical impact and divided into 2 groups (n=6 each). The experimental group was injected with MSCs (0.3x10(6)) intravenously one day after TBI, whereas the control group was injected with saline. MSCs were harvested from male mice, and male to female transplantation was performed to identify male donor cells within female recipient animals. This was achieved by localizing Y chromosomes within the female mice. Neurological function was assessed using the Morris water maze and foot fault tests. All mice were sacrificed 35 days after TBI. Brain sections were stained using in situ hybridization and immunohistochemistry to identify MSCs as well as to analyze vascular density following MSC treatment. Both modalities of testing demonstrated significant improvement in neurological function in the MSC-treated group compared to the saline-treated control group (p<0.05). Histologically, Y chromosome labeled MSCs were easily identified in the injured brain, localized primarily around the lesion boundary zone. There was also a significant increase in vascular density in the lesion boundary zone and hippocampus of MSC-treated mice compared to control mice. This is the first study to show beneficial effects of MSC treatment after TBI in mice.

Neuroadaptation of presbyopia-correcting intraocular lenses

PURPOSE OF REVIEW

Advances in the design of intraocular lenses give options to patients for some return to the optical accommodation needed to focus on objects at different distances. Technology is only improving these options for presbyopic-correcting intraocular lenses. Surgeons must consider the possible neuroadaptation abilities in patients that may help in the success of using these lenses.

RECENT FINDINGS

The hierarchy of the visual system allows two disparate retinal images to combine to form a single picture with depth. Attempts to correct presbyopia with intraocular lenses add complexity to the pathway with the possible introduction of monovision or intraocular rivalry. The neuroadaptation involved in successful use of these lenses has not been study but has been well established in other neurologic processing.

SUMMARY

Understanding what patient selection factors are important for neuroadaptation may contribute to outcome success.

A review of pharmacological treatments used in experimental models of traumatic brain injury

PRIMARY OBJECTIVE

We provide a review of recent chronic and delayed rehabilitative pharmacological treatments examined in experimental models of traumatic brain injury. There is a specific emphasis on studies aiming to enhance cognitive recovery.

MAIN OUTCOMES AND RESULTS

Decreased neuronal activity is believed to contribute to persistent cognitive disabilities. Neurotransmitter based rehabilitative treatments that increase neuronal activity may assist in the recovery of cognitive function. However, timing and dosage of drug treatment are influential in cognitive enhancement. Drug treatments that affect single and multiple neurotransmitter systems have the ability to significantly influence recovery of function following brain injury.

CONCLUSIONS

Understanding the relationship between neural disturbances and functional deficits following brain injury is challenging. Cognitive impairment may be the result of a single event or multiple events that occur after the initial insult. Increasing neuronal activity during the chronic phase of injury seems to be an effective treatment strategy for facilitating cognitive recovery. Pharmacological agents do not necessarily display the same effects in an injured brain as in a non-injured brain. Thus, further research is needed to establish the effectiveness of rehabilitative drug treatments.

Collagen scaffolds populated with human marrow stromal cells reduce lesion volume and improve functional outcome after traumatic brain injury

OBJECTIVE

Traumatic brain injury (TBI) causes extensive loss of cerebral parenchyma; however, no strategy for reconstruction has been clinically effective. Our group and others have used human marrow stromal cells (hMSCs) to treat rats subjected to TBI and found no significant changes in the lesion volume, although functional outcome was improved significantly. To identify new ways of delivering hMSCs into the injured brain and to maximize the therapeutic benefits of hMSC treatment, we investigated the use of collagen scaffolds implanted with hMSCs as a cell delivery system for treatment of TBI.

METHODS

Collagen scaffolds populated with 3 x 10(6) hMSCs were transplanted into the lesion cavity of the injured cortex 4 days after TBI, and the rats were euthanized 35 days after TBI. We measured sensorimotor function and spatial learning using an array of function tests, and the brain tissue was processed for histopathology analysis.

CONCLUSION

The data show that scaffolds populated by hMSCs improve spatial learning and sensorimotor function, reduce the lesion volume, and foster the migration of hMSCs into the lesion boundary zone after TBI in rats. hMSC-populated scaffolds may be a new way to reconstruct the injured brain and improve neurological function after TBI.

Role of gender in outcome after traumatic brain injury and therapeutic effect of erythropoietin in mice

The aim of this study was to investigate the role of gender in histological and functional outcome, angiogenesis, neurogenesis and therapeutic effects of recombinant human erythropoietin (rhEPO) in mice after traumatic brain injury (TBI). TBI caused both tissue loss in the cortex and cell loss in the dentate gyrus (DG) in the injured hemisphere at day 35 post TBI without a significant gender difference. After TBI, sensorimotor deficits were significantly larger in male mice compared to females, while similar spatial learning deficits were present in both genders. TBI alone significantly stimulated angiogenesis and neurogenesis in the cortex and in the DG of injured hemispheres in both genders. rhEPO at a dose of 5000 units/kg body weight administered intraperitoneally at 6 h, and 3 and 7 days after injury significantly reduced lesion volume and DG cell loss examined at day 35 after TBI as well as dramatically improved sensorimotor and spatial learning performance without an obvious gender proclivity. rhEPO significantly enhanced neurogenesis in the cortex and the DG of the ipsilateral hemisphere in male TBI mice. rhEPO did not affect angiogenesis in the ipsilateral cortex and DG in both genders after TBI. The present data demonstrate that posttraumatic administration of rhEPO improves histological and functional outcome in both genders, which may be mediated by reducing cortical tissue damage and DG cell loss in the ipsilateral hemisphere. In addition, the major gender propensity observed in the present study with mice after TBI without treatment is limited to sensorimotor deficits and cell proliferation.

Treatment of traumatic brain injury in rats with erythropoietin and carbamylated erythropoietin

OBJECT

This study was designed to investigate the neuroprotective properties of recombinant erythropoietin (EPO) and carbamylated erythropoietin (CEPO) administered following traumatic brain injury (TBI) in rats.

METHODS

Sixty adult male Wistar rats were injured with controlled cortical impact, and then EPO, CEPO, or a placebo (phosphate-buffered saline) was injected intraperitoneally. These injections were performed either 6 or 24 hours after TBI. To label newly regenerating cells, bromodeoxyuridine was injected intraperitoneally for 14 days after TBI. Blood samples were obtained on Days 1, 2, 3, 7, 14, and 35 to measure hematocrit. Spatial learning was tested using the Morris water maze. All rats were killed 35 days after TBI. Brain sections were immunostained as well as processed for the enzyme-linked immunosorbent assay to measure brain-derived neurotrophic factor (BDNF).

RESULTS

A statistically significant improvement in spatial learning was seen in rats treated with either EPO or CEPO 6 or 24 hours after TBI (p < 0.05); there was no difference in the effects of EPO and CEPO. Also, these drugs were equally effective in increasing the number of newly proliferating cells within the dentate gyrus at both time points. A statistically significant increase in BDNF expression was seen in animals treated with both EPO derivatives at 6 or 24 hours after TBI. Systemic hematocrit was significantly increased at 48 hours and 1 and 2 weeks after treatment with EPO but not with CEPO.

CONCLUSIONS

These data demonstrate that at the doses used, EPO and CEPO are equally effective in enhancing spatial learning and promoting neural plasticity after TBI.

Basic fibroblast growth factor promotes bone marrow stromal cell transplantation-mediated neural regeneration in traumatic brain injury

The current study was designed to evaluate the effects of basic fibroblast growth factor (bFGF) on human BMSC (hBMSC) transplantation-mediated neural regeneration in traumatic brain injury (TBI). Fibrin gel was used as a delivery vehicle to release bFGF locally in the TBI sites in a controlled manner. To test this hypothesis, hBMSCs suspended in fibrin gel containing bFGF were transplanted to rat TBI sites. Transplantation of hBMSCs suspended in fibrin gel without bFGF served as a control. hBMSC transplantation and bFGF treatment showed enhanced neural tissue regeneration than that of the control. The infarction volume and apoptotic activity of the transplanted hBMSCs were significantly decreased, and functional outcomes were significantly improved in the hBMSC transplantation and bFGF treatment group than in the control group. This study demonstrates that bFGF significantly enhances histological and functional recovery when used in hBMSC transplantation therapy in TBI.

Treatment of traumatic brain injury with a combination therapy of marrow stromal cells and atorvastatin in rats

OBJECTIVE

This study investigated the effects of a combination therapy of marrow stromal cells (MSCs) and statins (atorvastatin) after traumatic brain injury in rats.

METHODS

Thirty-two female Wistar rats were injured by controlled cortical impact and divided into four groups. Group I was injected with MSCs (1 x 10(6)) intravenously 24 hrs after traumatic brain injury. Group II was administered atorvastatin (0.5 mg/kg) orally for 14 days starting 24 hours after traumatic brain injury. Group III received MSCs (1 x 10(6)) combined with atorvastatin (0.5 mg/kg). Group IV (control) was injected with saline. MSCs were harvested from the bone marrow of male rats to identify male donor cells within female recipient animals by localization of Y chromosomes. Functional analysis was performed using modified neurological severity scores and the Morris water maze test. Animals were sacrificed 35 days after injury and brain sections stained with immunohistochemistry.

RESULTS

No functional improvement was seen in animals treated with MSCs or atorvastatin alone (Groups I and II). However, functional improvement was seen with both testing modalities (modified neurological severity scores and Morris water maze) in animals receiving combination therapy (Group III). Microscopic analysis showed that significantly more MSCs were present in animals receiving combination therapy than in those receiving MSCs alone. Also, significantly more endogenous cellular proliferation was seen in the hippocampus and injury boundary zone of the combination therapy group than in the monotherapy or control groups.

CONCLUSION

When administered in combination with MSCs, atorvastatin increases MSC access and/or survival within the injured brain and enhances functional recovery compared with monotherapy.

Human marrow stromal cell treatment provides long-lasting benefit after traumatic brain injury in rats

OBJECTIVE

This study was designed to investigate the effects of human bone marrow stromal cell (hMSC) administration in rats for 3 months after traumatic brain injury (TBI).

METHODS

Adult male Wistar rats (n = 60) were injured with controlled cortical impact and divided into four groups. The three treatment groups (n = 10 each) were injected with 2 x 10, 4 x 10, and 8 x 10 hMSCs, respectively, intravenously, whereas the control group (n = 30) received phosphate-buffered saline. All injections were performed 1 day after injury into the tail veins of rats. Neurological functional evaluation of animals was performed before and after injury by use of Neurological Severity Scores. Animals were sacrificed 3 months after TBI, and brain sections were stained by immunohistochemistry.

RESULTS

Statistically significant improvement in functional outcome was observed in all three treatment groups compared with control values (P < 0.05). This benefit was visible 14 days after TBI and persisted until 3 months (end of trial). There was no difference in functional outcome among the three treatment groups. Histological analysis showed that hMSCs were present in the lesion boundary zone at 3 months with all three doses tested.

CONCLUSION

hMSCs injected in rats after TBI survive until 3 months and provide long-lasting functional benefit. Functional improvement may be attributed to stimulation of endogenous neurorestorative functions such as neurogenesis and synaptogenesis.

Long-term recovery after bone marrow stromal cell treatment of traumatic brain injury in rats

OBJECT

This study was designed to follow the effects of bone marrow stromal cell (BMSC) administration in rats after traumatic brain injury (TBI) for a 3-month period.

METHODS

Forty adult female Wistar rats were injured by a controlled cortical impact and, 1 week later, were injected intravenously with one of three different doses of BMSCs (2 x 10(6), 4 x 10(6), or 8 x 10(6) cells per animal) obtained in male rats. Control rats received phosphate-buffered saline (PBS). Neurological function in these rats was studied using a neurological severity scale (NSS). The rats were killed 3 months after injury, and immunohistochemical stains were applied to brain samples to study the distribution of the BMSCs. Additional brain samples were analyzed by quantitative enzyme-linked immunosorbent assays to measure the expression of the growth factors brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF). Three months after injury, BMSCs were present in the injured brain and their number was significantly greater in animals that received 4 x 10(6) or 8 x 10(6) BMSCs than in animals that received 2 x 10(6) BMSCs. The cells were primarily distributed around the lesion boundary zone. Functional outcome was significantly better in rats that received 4 x 10(6) or 8 x 10(6) BMSCs, compared with control animals, although no improvement was seen in animals that received 2 x 10(6) BMSCs. All doses of BMSCs significantly increased the expression of BDNF but not that of NGF; however, this increase was significantly larger in animals that received 4 x 10(6) or 8 x 10(6) BMSCs than in controls or animals that received 2 x 10(6) BMSCs.

CONCLUSIONS

In summary, when injected in rats after TBI, BMSCs are present in the brain 3 months later and significantly improve functional outcome.

Development of Systems of Care for Persons With Traumatic Brain Injury

The history of the development of comprehensive systems of care for treatment of survivors of traumatic brain injury is reviewed in relation to publications in The Journal of Head Trauma Rehabilitation (JHTR). This development has drawn from multiple other areas of clinical endeavor and has extended the range of services from an acute inpatient focus to include multisite delivery and lifetime supported living aspects. Widespread implementation of this comprehensive system approach continues to lag because of coordination and financing challenges. The history and details of these developments are comprehensively reflected in the published articles of JHTR over the past 20 years.

Marrow Stromal Cell Transplantation after Traumatic Brain Injury Promotes Cellular Proliferation within the Brain

OBJECTIVE

This study was designed to investigate the effects of intracerebral as well as intravenous administration of bone marrow stromal cells (MSCs) on endogenous cellular proliferation after traumatic brain injury (TBI).

METHODS

Two experimental groups of Wistar rats were studied. One group received MSCs intracerebrally, and the other group received MSCs intravenously after injury by controlled cortical impact. MSCs were harvested from the bone marrow of male Wistar rats. For the intracerebral study, 24 male rats were divided into three groups (eight rats per group): rats injected with MSCs (1 x 10(6)) intracerebrally 1 day after TBI; 2) rats injected with phosphate-buffered saline intracerebrally 1 day after TBI; and 3) sham group not subjected to injury and not administered treatment. For the intravenous study, 10 female Wistar rats were injected 1 day after TBI with either MSCs (2 x 10(6)) (n = 5) or phosphate-buffered saline (n = 5) via the tail vein. Neurological function of the rats was evaluated with modified neurological severity scores and rotarod motor test. All rats were injected with bromodeoxyuridine intraperitoneally, to label the newly generating cells. Rats were killed 15 days after TBI, and coronal brain sections were stained immunohistochemically with diaminobenzidine to identify newly generating bromodeoxyuridine-positive cells. To study the differentiation of newly generating cells into neurons, sections were also double-stained for neuronal markers (Tuj1, doublecortin, NeuN) with fluorescein isothiocyanate.

RESULTS

The data demonstrate that newly generating cells were mainly present in the subventricular zone, hippocampal formation, and boundary zone of contusion of both treated and control animals. Intracerebral MSC treatment significantly increased the progenitor cell proliferation in the subventricular zone and boundary zone compared with the controls, whereas intravenous MSC treatment enhanced this endogenous proliferation in subventricular zone, hippocampus, and boundary zone. In both groups, some of the new cells revealed positive staining for neuronal markers. A statistically significant functional improvement was observed in both the intracerebrally as well as intravenously treated groups.

CONCLUSION

Intracerebral and intravenous MSC administration promotes endogenous cellular proliferation after TBI in rats. This may contribute to the functional improvement observed in these rats.

Atorvastatin Reduces Neurological Deficit and Increases Synaptogenesis, Angiogenesis, and Neuronal Survival in Rats Subjected to Traumatic Brain Injury

Statins administered postischemia promote functional improvement in rats, independent of their capability to lower cholesterol. We therefore tested the effect of statin treatment on traumatic brain injury (TBI) in rats. Atorvastatin was orally administered (1 mg/kg/day) to Wistar rats starting 1 day after TBI for 7 consecutive days. Control animals received saline. Modified Neurological Severity Scores and Corner tests were utilized to evaluate functional response to treatment. Bromodeoxyuridine (BrdU, 100 mg/kg) was also intraperitoneally injected daily for 14 consecutive days to label the newly generated endothelial cells. Rats were sacrificed at day 14 after TBI, and the brain samples were processed for immunohistochemical staining. Atorvastatin administration after brain injury significantly reduced the neurological functional deficits, increased neuronal survival and synaptogenesis in the boundary zone of the lesion and in the CA3 regions of the hippocampus, and induced angiogenesis in these regions. The results suggest that atorvastatin may provide beneficial effects in experimental TBI.