Erythropoietin (EPO) improves functional recovery after traumatic brain injury (TBI). Here, we investigated the role of vascular endothelial growth factor (VEGF) and VEGF receptor 2 (VEGFR2) on EPO-induced therapeutic efficacy in rats after TBI. Young male Wistar rats were subjected to unilateral controlled cortical impact injury and then infused intracerebroventricularly with either a potent selective VEGFR2 inhibitor SU5416 or vehicle dimethyl sulfoxide. Animals from both groups received delayed EPO treatment (5,000 U/kg in saline) administered intraperitoneally daily at 1, 2, and 3 days post injury. TBI rats treated with saline administered intraperitoneally daily at 1, 2, and 3 days post injury served as EPO treatment controls. 5-bromo-2-deoxyuridine was administered to label dividing cells. Spatial learning and sensorimotor function were assessed using a modified Morris water maze test and modified neurological severity score, respectively. Animals were sacrificed at 4 days post injury for measurement of VEGF and VEGFR2 or 35 days post injury for evaluation of cell proliferation, angiogenesis and neurogenesis. EPO treatment promoted sensorimotor and cognitive functional recovery after TBI. EPO treatment increased brain VEGF expression and phosphorylation of VEGFR2. EPO significantly increased cell proliferation, angiogenesis and neurogenesis in the dentate gyrus after TBI. Compared to the vehicle, SU5416 infusion significantly inhibited phosphorylation of VEGFR2, cell proliferation, angiogenesis, and neurogenesis as well as abolished functional recovery in EPO-treated TBI rats. These findings indicate the VEGF/VEGFR2 activation plays an important role in EPO-mediated neurobehavioral recovery and neurovascular remodeling after TBI.

Object

Delayed (24 hours post injury) treatment with erythropoietin (EPO) improves functional recovery following experimental traumatic brain injury (TBI). In this study, we tested whether therapeutic effects of delayed EPO treatment for TBI are dose-dependent in an attempt to establish an optimal dose paradigm for the delayed EPO treatment.

Methods

Experimental TBI was performed in anesthetized young adult male Wistar rats using a controlled cortical impact device. Sham animals underwent the same surgical procedure without injury. The animals (8 rats/group) received 3 intraperitoneal injections of EPO (0, 1000, 3000, 5000 or 7000 U/kg body weight, at 24, 48 and 72 hours) after TBI. Sensorimotor and cognitive functions were assessed using a modified neurological severity score and foot fault test, and Morris water maze tests, respectively. Animals were sacrificed 35 days after injury and brain sections stained for immunohistochemical analyses.

Results

Compared to the saline treatment, EPO treatment at doses from1000 to 7000 U/kg did not alter lesion volume but significantly reduced hippocampal neuron loss, enhanced angiogenesis and neurogenesis in the injured cortex and hippocampus, and significantly improved sensorimotor function and spatial learning. The medium dose at 5000 U/kg exhibited a significant improvement in histological and functional outcomes compared with the lower or higher EPO dose groups.

Conclusions

These data demonstrate that delayed (24 hours post injury) treatment with EPO provides dose-dependent neurorestoration which may contribute to improved functional recovery after TBI, implying that application of an optimal dose of EPO is likely to increase successful preclinical and clinical trials for treatment of TBI.

Abstract

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 (3×106) or hMSCs (3×106) 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.

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 T2 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, FTand T2 can be used to evaluate treatment-induced white matter recovery, which may facilitate restorative therapy in patients with TBI.

Background

Our previous studies demonstrated that simvastatin reduced neuronal death, increased neurogenesis, and promoted functional recovery after TBI. Objective: To investigate the effect of simvastatin on angiogenesis after TBI, and the related signaling pathways.

Methods

Saline or simvastatin (1 mg/kg) was administered orally to rats starting at day 1 after TBI or sham surgery and then daily for 14 days. Rats were sacrificed at 3 and 14 days after treatment. Brain sections and tissues were prepared for immunohistochemical staining, ELISA, and Western blot analysis, respectively. Cultured rat brain microvascular endothelial cells (RBMVECs) were subjected to oxygen-glucose deprivation (OGD) followed by immunocytochemical staining with phallotoxins and vascular endothelial growth factor receptor-2 (VEGFR-2). Western blot analysis was carried out to examine the simvastatin-induced activation of the v-akt murine thymoma viral oncogene homolog (Akt) signaling pathway. The expression of VEGFR-2 was detected by ELISA.

Results

Simvastatin significantly increased the length of vascular perimeter, promoted the proliferation of endothelial cells, and improved the sensorimotor function after TBI. Simvastatin stimulated endothelial cell tube formation after OGD in vitro. VEGFR-2 expression in both brain tissues and cultured RBMVECs was enhanced after simvastatin treatment, which may be modulated by activation of Akt. Akt-dependent endothelial nitric oxide synthase (eNOS) phosphorylation was also induced by simvastatin in vivo and in vitro.

Conclusion

Simvastatin augments TBI-induced angiogenesis in the lesion boundary zone and hippocampus and improves functional recovery. Simvastatin also promotes angiogenesis in vitro. These beneficial effects on angiogenesis may be related to simvastatin-induced activation of the VEGFR-2/Akt/eNOS signaling pathway.

Erythropoietin (EPO) improves functional recovery after traumatic brain injury (TBI). This study was designed to investigate long-term (3 mo) effects of EPO on brain remodeling and functional recovery in rats after TBI. Young male Wistar rats were subjected to unilateral controlled cortical impact injury. TBI rats were divided into the following groups: 1) Saline group (n = 7); 2) EPO-6h group (n = 8); and 3) EPO-24h group (n = 8). EPO (5,000 U/kg in saline) was administered intraperitoneally at 6 h, and 1 and 2 days (EPO-6h group) or at 1, 2, and 3 days (EPO-24h group) post injury. Neurological function was assessed using a modified neurological severity score, footfault and Morris water maze tests. Animals were sacrificed at 3 mos after injury and brain sections stained for immunohistochemical analyses. Compared to the saline, EPO-6h treatment significantly reduced cortical lesion volume, while EPO-24h therapy did not affect the lesion volume (P<0.05). Both the EPO-6h and EPO-24h treatments significantly reduced hippocampal cell loss (P<0.05), promoted angiogenesis (P<0.05) and increased endogenous cellular proliferation (BrdU-positive cells) in the injury boundary zone and hippocampus (P<0.05) compared to saline controls. Significantly enhanced neurogenesis (BrdU/NeuN-positive cells) was seen in the dentate gyrus of both EPO groups compared to the saline group. Both EPO treatments significantly improved long-term sensorimotor and cognitive functional recovery after TBI. In conclusion, the beneficial effects of posttraumatic EPO treatment on injured brain persisted for at least 3 months. The long-term improvement in functional outcome may in part be related to the neurovascular remodeling induced by EPO.

Abstract

Cell therapy promotes brain remodeling and improves functional recovery after various central nervous system disorders, including traumatic brain injury (TBI). We tested the hypothesis that treatment of TBI with intravenous administration of human marrow stromal cells (hMSCs) provides therapeutic benefit in modifying hemodynamic and structural abnormalities, which are detectable by in vivo MRI. hMSCs were labeled with superparamagnetic iron oxide (SPIO) nanoparticles. Male Wistar rats (300–350 g, n=18) subjected to controlled cortical impact TBI were intravenously injected with 1 mL of saline (n=9) or hMSCs in suspension (n=9, approximately 3×106 SPIO-labeled hMSCs) 5 days post-TBI. In vivo MRI measurements consisting of cerebral blood flow (CBF), T2-weighted imaging, and 3D gradient echo imaging were performed for all animals 2 days post-TBI and weekly for 6 weeks. Functional outcome was evaluated with modified neurological severity score and Morris water maze test. Cell engraftment was detected in vivo by 3D MRI and confirmed by double staining. Ventricle and lesion volumetric alterations were measured using T2 maps, and hemodynamic abnormality was tracked by MRI CBF measurements. Our data demonstrate that treatment with hMSCs following TBI diminishes hemodynamic abnormalities by early restoration and preservation of CBF in the brain regions adjacent to and remote from the impact site, and reduces generalized cerebral atrophy, all of which may contribute to the observed improvement of functional outcome.

Object

Carbamylated erythropoietin (CEPO) is a modified erythropoietin molecule that does not affect hematocrit. In this study, we compared the efficacy of a single dose with triple dose of CEPO treatment of traumatic brain injury (TBI) in rats.

Methods

TBI was induced by controlled cortical impact over the left parietal cortex. CEPO (50 μg/kg) was administered intraperitoneally in rats with TBI at 6 hours (CEPO x 1 group) or 6, 24 and 48 hours (CEPO x 3 group) post injury. Neurological function was assessed using a modified neurological severity score, footfault and Morris water maze tests. Animals were sacrificed 35 days after injury and brain sections stained for immunohistochemistry to assess lesion volume, cell loss, cell proliferation, angiogenesis and neurogenesis after CEPO treatment.

Results

Compared to the vehicle treatment, single treatment of CEPO (6 hours) significantly reduced lesion volume and hippocampal cell loss, enhanced angiogenesis and neurogenesis in the injured cortex and hippocampus, and significantly improved sensorimotor functional recovery and spatial learning in rats after TBI. Importantly, triple dosing of CEPO (6, 24 and 48 hours) further reduced lesion volume and improved functional recovery and neurogenesis compared to the CEPO x 1 group.

Conclusions

Our results indicate that CEPO has considerable therapeutic potential in TBI and related pathologies and furthermore that repeated dosing in the sub-acute phase might have important pharmacological relevance.

We have previously demonstrated that human marrow stromal cells (hMSCs) embedded in collagen I scaffolds significantly enhance the restorative therapeutic effect of hMSCs after traumatic brain injury (TBI). In this study, we test the hypothesis that the collagen scaffold alters gene expression in hMSCs and that hMSCs impregnated into scaffolds increase the astrocytic expression of vascular endothelial growth factor (VEGF) in the injured brain. Following TBI induced by controlled cortical impact injury, scaffold with hMSCs (3.0 × 106), hMSCs-only and saline were implanted into the lesion cavity one week after brain injury (n = 8/each group). Morris water Maze and modified neurological severity scores were performed to evaluate the spatial learning and sensorimotor functions, respectively. Lesion volume and expression of VEGF were measured one week after different treatments. In vitro, total RNA from hMSCs was extracted one week after culture with or without collagen I scaffold for evaluation of gene microarrays. Furthermore, an RT-PCR study on a select subgroup of genes was performed to identify the changes of expression between the culturing hMSCs with collagen scaffolds and hMSCs only. The treatment of TBI with collagen scaffold impregnated with hMSCs significantly decreases the functional deficits from TBI within 7 days after treatment, and significantly enhances the VEGF expression of astrocytes in the injured brain compared to the hMSCs-only group. In vitro data indicate that collagen scaffolds stimulate hMSCs to express multiple factors which may contribute to hMSC survival, tissue repair and functional recovery after TBI.

Object

This study was designed to investigate the efficacy of delayed thymosin β4 (TB4) treatment of traumatic brain injury (TBI) in rats.

Methods

Young adult male Wistar rats were divided into the following groups: 1) Sham group (6 rats); 2) TBI + Saline group (9 rats); 3) and TBI + Tβ4 group (10 rats). TBI was induced by controlled cortical impact over the left parietal cortex. Thymosin β4 (6 mg/kg) or saline was administered intraperitoneally starting at Day 1 and then every 3 days for an additional 4 doses. Neurological function was assessed using a modified neurological severity score (mNSS), footfault and Morris water maze tests. Animals were killed 35 days after injury, and brain sections stained for immunohistochemistry to assess angiogenesis, neurogenesis, and oligodendrogenesis after Tβ4 treatment.

Results

Compared to the saline treatment, delayed Tβ4 treatment did not affect lesion volume but significantly reduced hippocampal cell loss, enhanced angiogenesis and neurogenesis in the injured cortex and hippocampus, increased oligodendrogenesis in the CA3 region, and significantly improved sensorimotor functional recovery and spatial learning.

Conclusions

These data for the first time demonstrate that delayed administration of Tβ4 significantly improves histological and functional outcomes in rats with TBI, indicating that Tβ4 has considerable therapeutic potential for patients with TBI.

Traumatic brain injury (TBI) remains a major cause of death and permanent disability worldwide, especially in children and young adults. A total of 1.5 million people experience head trauma each year in the United States, with an annual economic cost exceeding $56 billion. Unfortunately, almost all Phase III TBI clinical trials have yet to yield a safe and effective neuroprotective treatment, raising questions regarding the use of neuroprotective strategies as the primary therapy for acute brain injuries. Recent preclinical data suggest that neurorestorative strategies that promote angiogenesis (formation of new blood vessels from pre-existing endothelial cells), axonal remodeling (axonal sprouting and pruning), neurogenesis (generation of new neurons) and synaptogenesis (formation of new synapses) provide promising opportunities for the treatment of TBI. This review discusses select cell-based and pharmacological therapies that activate and amplify these endogenous restorative brain plasticity processes to promote both repair and regeneration of injured brain tissue and functional recovery after TBI.

Erythropoietin (EPO) promotes functional recovery after traumatic brain injury (TBI). This study was designed to investigate whether EPO treatment promotes contralateral corticospinal tract (CST) plasticity in the spinal cord in rats after TBI. Biotinylated dextran amine (BDA) was injected into the right sensorimotor cortex to anterogradely label the CST. TBI was induced by controlled cortical impact over the left parietal cortex immediately after BDA injections. EPO (5,000 U/kg) or saline was administered intraperitoneally at Days 1, 2, and 3 post injury. Neurological function was assessed using a modified neurological severity score (mNSS) and footfault tests. Animals were sacrificed 35 days after injury and brain sections stained for histological analysis. Compared to the saline treatment, EPO treatment significantly improved sensorimotor functional outcome (lower mNSS and reduced footfaults) from Days 7 to 35 post injury. TBI alone significantly stimulated contralateral CST axon sprouting toward the denervated gray matter of the cervical and lumbar spinal cord; however, EPO treatment further significantly increased the axon sprouting in TBI rats although EPO treatment did not significantly affect axon sprouting in sham animals. The contralesional CST sprouting was highly and positively correlated with sensorimotor recovery after TBI. These data demonstrate that CST fibers originating from the contralesional intact cerebral hemisphere are capable of sprouting into the denervated spinal cord after TBI and EPO treatment, which may at least partially contribute to functional recovery.

Object

This study was designed to investigate delayed erythropoietin (EPO) treatment for traumatic brain injury (TBI) in rats comparing efficacy of a single dose with triple doses.

Methods

Young adult male Wistar rats were randomly divided into the following groups: 1) Sham group (n = 6); 2) TBI + Saline group (n = 6); 3) TBI + EPOx1 group (n = 6); and 4) TBI + EPOx3 group (n = 7). TBI was induced by controlled cortical impact over the left parietal cortex. EPO (5,000 U/kg) or saline was administered intraperitoneally at 1 day (EPOx1 group) or at days 1, 2, and 3 (EPOx3 group) post injury. Neurological function was assessed using a modified neurological severity score (mNSS), footfault and Morris water maze tests. Animals were sacrificed 35 days after injury and brain sections stained for immunohistochemistry.

Results

Compared to the saline treatment, EPO treatment in both the EPOx1 and EPOx3 groups significantly reduced hippocampal cell loss, enhanced angiogenesis and neurogenesis in the injured cortex and hippocampus, and significantly improved neurological functional outcome. The EPOx3 group exhibited significantly improved functional and histological outcomes compared with the EPOx1 group.

Conclusions

These data demonstrate that delayed posttraumatic administration of EPO significantly improves histological and long-term functional outcomes in rats after TBI. The triple doses of delayed EPO treatment exhibit better histological and functional outcomes in rats although a single dose of EPO provides substantial benefits compared to saline treatment.

Abstract

Traumatic brain injury (TBI) elicits a strong inflammatory response that contributes to the acute pathological processes seen following TBI, including cerebral edema and disruption of the blood–brain barrier (BBB), in addition to longer-term neurological damage and cognitive impairment. Proteasome inhibitors reduce vascular thrombotic and inflammatory events and consequently protect vascular function. In the present study we evaluated the neuroprotective effect of Velcade® (bortezomib), a potent and selective inhibitor of proteasomes, which is in clinical use for the treatment of multiple myeloma. When administered within 2 h after TBI onset, Velcade reduced inflammatory responses, lesion volume, and neurological functional deficits, and enhanced neuronal survival. Western blot and ELISA showed that Velcade decreased the expression of NF-κB. These results suggest that in the experimental setting, Velcade is an effective neuroprotective agent for the treatment of TBI.

Objective

Our previous studies demonstrated that simvastatin treatment promotes neuronal survival and reduces inflammatory cytokine release from astrocytes after traumatic brain injury (TBI) in rats. Since reactive astrocytes produce inflammation mediators, in the current study we investigated the effect of simvastatin on astrocyte activation after TBI and its underlying signaling mechanisms.

Methods

Saline or simvastatin (1 mg/kg) was orally administered to rats starting at Day 1 after TBI and then daily for 14 days. Rats were sacrificed at 1, 3, 7, 14 days after treatment. Brain sections and tissues were prepared for immunohistochemical staining and Western blot analysis, respectively. Cultured astrocytes were subjected to oxygen-glucose deprivation (OGD) and followed by immunocytochemical staining with GFAP/caveolin-1 and Western blot analysis. Lipid rafts were isolated from the cell lysate and Western blot was carried out to detect the changes in epidermal growth factor receptor (EGFR) expression and phosphorylation in the lipid rafts.

Results

Simvastatin significantly promoted neuronal survival after TBI and attenuated activation of astrocytes. Simvastatin modified the caveolin-1 expression in lipid rafts in astrocyte cell membrane, suppressed the phosphorylation of EGFR in lipid rafts of astrocytes after OGD, and inhibited the OGD-induced interleukin-1 (IL-1) production.

Conclusions

These data suggest that simvastatin reduces reactive astrogliosis and rescues neuronal cells after TBI. These beneficial effects of simvastatin may be mediated by inhibiting astrocyte activation after TBI through modifying the caveolin-1 expression in lipid rafts and the subsequent modulation of EGFR phosphorylation in lipid rafts.

Traumatic brain injury and stroke are major causes of mortality and morbidity worldwide. Unfortunately, almost all phase-III neuroprotective clinical trials for stroke and traumatic brain injury have shown no benefits; this has raised concerns regarding neuroprotective strategy alone as a therapy for acute brain injuries. There is therefore a compelling need to develop treatments that promote the repair and regeneration of injured brain tissue and functional recovery. Recent findings suggest that strategies to enhance angiogenesis and neurogenesis for brain injuries may provide promising opportunities to improve clinical outcomes during brain functional recovery. This article reviews current data on angiogenesis and neurogenesis in the adult brain after stroke and traumatic brain injury. Select cell-based and pharmacological therapies that promote angiogenesis and neurogenesis designed to restore neurological function after brain injuries are described. These findings highlight the need for a better understanding of injury- and therapy-induced angiogenesis and neurogenesis in the adult and suggest that the manipulation of endogenous neural precursors and endothelial cells is a potential therapy for brain injury.

Abstract

Erythropoietin (EPO), essential for erythropoiesis, provides neuroprotection. The EPO receptor (EPOR) is expressed in both neural and non-neural cells in the brain. This study was designed to test the hypothesis that EPO provides beneficial therapeutic effects, even in the absence of the neural EPOR. In this study, EPOR-null mice were rescued with selective EpoR expression driven by the endogenous EpoR promoter in hematopoietic tissue, but not in the neural cells. Anesthetized young adult female EPOR-null and wild-type mice were subjected to traumatic brain injury (TBI) induced by controlled cortical impact. EPO (5000 U/kg) or saline was intraperitoneally administered at 6 h and 3 and 7 days post-injury. Sensorimotor and spatial learning functions were assessed. Expression of EPOR and its downstream signal proteins were evaluated by Western blot analysis. Our data demonstrated that EPO treatment significantly reduced cortical tissue damage and hippocampal cell loss, and improved spatial learning following TBI in both the wild-type and EPOR-null mice. EPO treatment significantly improved sensorimotor functional recovery, with better outcomes in the wild-type mice. EPO treatment upregulated anti-apoptotic proteins (p-Akt and Bcl-XL) in the ipsilateral hippocampus and cortex of the injured wild-type and EPOR-null mice. These data demonstrate that EPO significantly provides neuroprotection following TBI, even in the absence of EPOR in the neural cells, suggesting that its therapeutic benefits may be mediated through vascular protection.

Erythropoietin (EPO) provides neuroprotection and neurorestoration after traumatic brain injury (TBI). The EPO doses used for treatment of TBI significantly increase hematocrit, which may affect the efficacy of EPO therapy for TBI. The aim of this study was to investigate whether normalization of hematocrit would affect EPO efficacy for treatment of TBI. Young adult male Wistar rats were randomly divided into 4 groups: 1) Sham group (n=6); 2) TBI + saline group (n=6); 3) TBI + EPO group (n=6); and 4) TBI + EPO + hemodilution group (n=7). TBI was induced by controlled cortical impact over the left parietal cortex. EPO (5,000 U/kg) or saline was administered intraperitoneally at days 1, 2, and 3 post injury. Neurological function was assessed using a modified neurological severity score (mNSS), footfault and the Morris water maze (MWM) tests. Animals were sacrificed 35 days after injury and brain sections stained for immunohistochemistry. Compared to the saline treatment, EPO treatment significantly reduced hippocampal cell loss, enhanced angiogenesis and neurogenesis in the injured cortex and hippocampus, and significantly improved sensorimotor functional outcome (lowered mNSS and foot faults) and spatial learning (MWM test). Normovolemic hemodilution effectively normalized the hematocrit and did not significantly affect the histological and functional outcome of EPO therapy for TBI. These data for the first time demonstrate that increased hematocrit does not affect therapeutic effects of EPO on histological and long-term functional outcomes in rats after TBI and also suggest that neuroprotection and neurorestoration of EPO treatment are independent of hematocrit.

Object

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

Methods

C57BL/6J mice were injured with controlled cortical impact (n = 8) and treated with 0.3 × 106 hMSCs impregnated into three-dimensional porous collagen scaffolds transplanted into the lesion cavity. Additional experimental groups (n = 8 mice/group) were treated with scaffolds implanted alone into the lesion cavity, and 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 was processed for histopathological analysis.

Results

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

Conclusion

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

OBJECTIVE

This study was designed to investigate the long-term effects of simvastatin treatment after traumatic brain injury (TBI) in rats.

METHODS

Adult female Wistar rats (n=24) were injured with controlled cortical impact and divided into three groups. The first two groups were treated with simvastatin 0.5 mg/kg or 1 mg/kg administered orally for 14 days starting one day after TBI. The third group (control) received phosphate-buffered saline (PBS) orally for 14 days. Neurological functional outcome was measured with modified neurological severity scores (mNSS) performed 1 day before TBI and after TBI on Days 1, 4, 7, 14 and biweekly thereafter. All animals were sacrificed 3 months after TBI. Brain tissues of half of the animals were processed for preparation of paraffin-embedded sections for immunohistological studies. The remaining half was frozen for ELISA studies for quantification of brain-derived neurotrophic factor (BDNF) in hippocampus and cortex.

RESULTS

Results showed that both doses of simvastatin significantly improved functional outcome compared to control with no difference between the two doses. Simvastatin treatment of 1 mg/kg increased the number of morphologically intact neurons in hippocampus with 0.5 mg/kg having no significant effect. ELISA studies showed that 0.5 mg/kg of simvastatin significantly increased BDNF levels within hippocampus with 1 mg/kg having no significant effect; neither dose had any effect on BDNF levels within the cortex.

CONCLUSION

Simvastatin treatment provides long-lasting functional improvement after TBI in rats. It also enhances neuronal survival in the hippocampus and increases BDNF levels in the hippocampus secondary to simvastatin treatment.

Objective

Our previous studies demonstrated that simvastatin promotes neurological functional recovery after traumatic brain injury (TBI) in rat; however, the underlying mechanisms remain poorly understood. The purpose of this study was to investigate the anti-inflammatory effect of simvastatin by measuring the level of cytokines and activation of glial cells.

Methods

Controlled cortical impact injury was performed in adult male Wistar rats. The rats were randomly divided into three groups: sham, saline control group and simvastatin treatment group. Simvastatin was administered orally starting at day 1 after TBI until sacrifice. Animals were sacrificed at 1, 3, 7, 14, and 35 days after treatment. Functional outcome was measured using modified neurological severity scores (mNSS). ELISA and immunohistochemical staining were employed to measure the expression of IL-1β, IL-6 and TNF-α, and to identify activated microglia and astrocytes.

Results

At days 1 and 3 after simvastatin or saline treatment, cytokine levels in the lesion boundary zone were significantly higher in the simvastatin-treated rats and saline-treated rats compared to the sham group, peaking at day 3. Simvastatin only reduced the level of IL-1 β but not IL-6 and TNF-α compared with the saline group. Also, simvastatin reduced significantly the number of activated microglia and astrocytes compared to the saline control animals. There was also a trend towards improvement of mNSS score, reaching statistical significance (P=0.003) towards the end of the trial.

Conclusion

Our data demonstrate that TBI causes inflammatory reaction, including increased levels of IL-1β, IL-6 and TNF-α, as well as activated microglia. Simvastatin selectively reduces IL-1β expression and inhibits the activation of microglia and astrocytes after TBI, which may be one of the mechanisms underlying the therapeutic benefits of simvastatin treatment of TBI.

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 × 106 hMSCs, scaffolds alone, 3 × 106 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.

Background

This review summarizes promising approaches for the treatment of traumatic brain injury (TBI), which are either in preclinical or clinical trials.

Objective

The pathophysiology underlying neurological deficits after TBI is described. An overview of select therapies for TBI with neuroprotective and neurorestorative effects is presented.

Methods

A literature review of pre-clinical TBI studies and clinical TBI trials related to neuroprotective and neurorestorative therapeutic approaches is provided.

Results/conclusion

Nearly all phase II/III clinical trials in neuroprotection have failed to show any consistent improvement in outcome for TBI patients. The next decade will witness an increasing number of clinical trials which seek to translate preclinical research discoveries to the clinic. Promising drug- or cell-based therapeutic approaches include erythropoietin and its carbamylated form, statins, bone marrow stromal cells, stem cells singularly or in combination or with biomaterials to reduce brain injury via neuroprotection and promote brain remodeling via angiogenesis, neurogenesis, and synaptogenesis with a final goal to improve functional outcome of TBI patients. In addition, enriched environment and voluntary physical exercise show promise in promoting functional outcome after TBI, and should be evaluated alone or in combination with other treatments as therapeutic approaches for TBI.

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 0.5 mg of simvastatin combined with 2 × 106 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.

Abstract

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 0.5 mg of simvastatin combined with 2×106 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.