Treatment of neural injury with marrow stromal cells

Cell therapy in demyelinating diseases

Multiple sclerosis presents particular and serious problems to those attempting to develop cell-based therapies: the occurrence of innumerable lesions scattered throughout the CNS, axon loss, astrocytosis, and a continuing inflammatory process, to name but a few. Nevertheless, the limited and relatively focused nature of damage to oligodendrocytes and myelin, at least in early disease, the large body of available knowledge concerning the biology of oligodendrocytes, and the success of experimental myelin repair, have allowed cautious optimism that therapies may be possible. Here, we review the clinical and biological problems presented by multiple sclerosis in the context of cell therapies, and the neuroscientific background to the development of strategies for myelin repair. We attempt to highlight those areas where difficulties have yet to be resolved and draw on a variety of more recent experimental findings to speculate on how remyelinating therapies are likely to develop in the foreseeable future.

Investigation of neural progenitor cell induced angiogenesis after embolic stroke in rat using MRI

Using MRI, we investigated dynamic changes of brain angiogenesis after neural progenitor cell transplantation in the living adult rat subjected to embolic stroke. Neural progenitor cells isolated from the subventricular zone (SVZ) of the adult rat were labeled by superparamagnetic particles and intracisternally transplanted into the adult rat 48 h after stroke (n = 8). Before and after the transplantation, an array of MRI parameters were measured, including high resolution 3D MRI and quantitative T1, T1sat (T1 in the presence of an off-resonance irradiation of the macromolecules of brain), T2, the inverse of the apparent forward transfer rate for magnetization transfer (kinv), cerebral blood flow (CBF), cerebral blood volume (CBV), and blood-to-brain transfer constant (Ki) of Gd-DTPA. The von Willerbrand factor (vWF) immunoreactive images of coronal sections obtained at 6 weeks after cell transplantation were used to analyze vWF immunoreactive vessels. MRI measurements revealed that grafted neural progenitor cells selectively migrated towards the ischemic boundary regions. In the ischemic boundary regions, angiogenesis confirmed by an increase in vascular density and the appearance of large thin wall mother vessels was coincident with increases of CBF and CBV (CBF, P < 0.01; CBV, P < 0.01) at 6 weeks after treatment, and coincident with transient increases of K(i) with a peak at 2 to 3 weeks after cell therapy. Relative T1, T1sat, T2, and kinv decreased in the ischemic boundary regions with angiogenesis compared to that in the non-angiogenic ischemic region (T1, P < 0.01 at 6 weeks; T1sat, P < 0.05 at 2 to 6 weeks; T2, P < 0.05 at 3 to 6 weeks; kinvP < 0.05 at 6 weeks). Of these methods, Ki appear to be the most useful MR measurements which identify and predict the location and area of angiogenesis. CBF, CBV, T1sat, T1, T2, and kinv provide complementary information to characterize ischemic tissue with and without angiogenesis. Our data suggest that select MRI parameters can identify the cerebral tissue destined to undergo angiogenesis after treatment of embolic stroke with cell therapy.

Magnetic resonance tracking of human CD34+ progenitor cells separated by means of immunomagnetic selection and transplanted into injured rat brain

Magnetic resonance imaging (MRI) provides a noninvasive method for studying the fate of transplanted cells in vivo. We studied whether superparamagnetic nanoparticles (CD34 microbeads), used clinically for specific magnetic sorting, can be used as a magnetic cell label for in vivo cell visualization. Human cells from peripheral blood were selected by CliniMACS CD34 Selection Technology (Miltenyi). Purified CD34+ cells were implanted into rats with a cortical photochemical lesion, contralaterally to the lesion. Twenty-four hours after grafting, the implanted cells were detected in the contralateral hemisphere as a hypointense spot on T2 weighted images; the hypointensity of the implant decreased during the first week. At the lesion site we observed a hypointensive signal 10 days after grafting that persisted for the next 3 weeks, until the end of the experiment. Prussian blue and anti-human nuclei staining confirmed the presence of magnetically labeled human cells in the corpus callosum and in the lesion 4 weeks after grafting. CD34+ cells were also found in the subventricular zone (SVZ). Human DNA (a human-specific 850 base pair fragment of alpha-satellite DNA from human chromosome 17) was detected in brain tissue sections from the lesion using PCR, confirming the presence of human cells. Our results show that CD34 microbeads superparamagnetic nanoparticles can be used as a magnetic cell label for in vivo cell visualization. The fact that microbeads coated with different commercially available antibodies can bind to specific cell types opens extensive possibilities for cell tracking in vivo.

Functional recovery of neuronal activity in rat whisker-barrel cortex sensory pathway from freezing injury after transplantation of adult bone marrow stromal cells

The effect of transplantation of adult bone marrow stromal cells (MSCs) into the freeze-lesioned left barrel field cortex in the rat was investigated by measurement of local cerebral glucose utilization (lCMR(glc)) in the anatomic structures of the whisker-to-barrel cortex sensory pathway. Bone marrow stromal cells or phosphate-buffered saline (PBS) were injected intracerebrally into the boundary zone 1 h after induction of the freezing cortical lesion. Three weeks after surgery, the 2-[(14)C]deoxyglucose method was used to measure lCMR(glc) during right whisker stimulation. The volume of the primary necrotic freezing lesion was significantly reduced (P<0.05), and secondary retrograde degeneration in the left ventral posteromedial (VPM) thalamic nucleus was diminished in the MSC-treated group. Local cerebral glucose utilization measurements showed that the freezing cortical lesion did not alter the metabolic responses to stimulation in the brain stem trigeminal nuclei, but eliminated the responses in the left VPM nucleus and periphery of the barrel cortex in the PBS-treated group. The left/right (stimulated/unstimulated) lCMR(glc) ratios were significantly improved in both the VPM nucleus and periphery of the barrel cortex in the MSC-treated group compared with the PBS-treated group (P<0.05). These results indicate that MSC transplantation in adults may stimulate metabolic and functional recovery in injured neuronal pathways.

Axon growth and recovery of function supported by human bone marrow stromal cells in the injured spinal cord exhibit donor variations

Bone marrow stromal cells (MSC) are non-hematopoietic support cells that can be easily derived from bone marrow aspirates. Human MSC are clinically attractive because they can be expanded to large numbers in culture and reintroduced into patients as autografts or allografts. We grafted human MSC derived from aspirates of four different donors into a subtotal cervical hemisection in adult female rats and found that cells integrated well into the injury site, with little migration away from the graft. Immunocytochemical analysis demonstrated robust axonal growth through the grafts of animals treated with MSC, suggesting that MSC support axonal growth after spinal cord injury (SCI). However, the amount of axon growth through the graft site varied considerably between groups of animals treated with different MSC lots, suggesting that efficacy may be donor-dependent. Similarly, a battery of behavioral tests showed partial recovery in some treatment groups but not others. Using ELISA, we found variations in secretion patterns of selected growth factors and cytokines between different MSC lots. In a dorsal root ganglion explant culture system, we tested efficacy of conditioned medium from three donors and found that average axon lengths increased for all groups compared to control. These results suggest that human MSC produce factors important for mediating axon outgrowth and recovery after SCI but that MSC lots from different donors vary considerably. To qualify MSC lots for future clinical application, such notable differences in donor or lot-lot efficacy highlight the need for establishing adequate characterization, including the development of relevant efficacy assays.

G-CSF reduces infarct volume and improves functional outcome after transient focal cerebral ischemia in mice

Growth factors possess neuroprotective and neurotrophic properties in vitro, but few have been extensively studied in vivo after stroke. In the present study, we investigated the potential functional benefits of granulocyte colony-stimulating factor (G-CSF) administration after focal cerebral ischemia. Male mice underwent 60-minute middle cerebral artery occlusion (MCAO) and received G-CSF (50 microg/kg, subcutaneously) or vehicle (saline) at the onset of reperfusion. Granulocyte colony-stimulating factor-treated mice killed at 48 hours after MCAO revealed a >45% reduction (P<0.05) in lesion volume. In terms of body weight recovery, and in tests of motor (grid test and rotarod) and cognitive ability (water maze), MCAO significantly worsened the outcome in vehicle-treated mice as compared with shams (P<0.05). However, G-CSF treatment was beneficial as, compared with vehicle, this significantly improved weight recovery and motor ability. This effect was most apparent on the water maze where G-CSF-treated mice were indistinguishable from shams in terms of acquiring the task. These results indicate long-term beneficial effects of a single dose of G-CSF administered on reperfusion, and illustrate the need to further investigate the mechanisms of G-CSF action.

Adrenomedullin enhances therapeutic potency of mesenchymal stem cells after experimental stroke in rats

BACKGROUND AND PURPOSE

Adrenomedullin (AM) induces angiogenesis and inhibits cell apoptosis through the phosphatidylinositol 3-kinase/Akt pathway. Transplantation of mesenchymal stem cells (MSCs) has been shown to improve neurological deficits after stroke in rats. We investigated whether AM enhances the therapeutic potency of MSC transplantation.

METHODS

Male Lewis rats (n=100) were subjected to 2-hour middle cerebral artery occlusion. Immediately after reperfusion, rats were assigned randomly to receive intravenous transplantation of MSCs plus subcutaneous infusion of AM for 7 days (MSC+AM group), AM infusion alone (AM group), MSC transplantation alone (MSC group), or vehicle infusion (control group). Neurological and immunohistological assessments were performed to examine the effects of these treatments.

RESULTS

Some engrafted MSCs were positive for neuronal and endothelial cell markers, although the number of differentiated MSCs did not differ significantly between the MSC and MSC+AM groups. The neurological score significantly improved in the MSC, AM, and MSC+AM groups compared with the control group. Importantly, improvement in the MSC+AM group was significantly greater than that in the MSC and AM groups. There was marked induction of angiogenesis in the ischemic penumbra in the MSC+AM group, followed by the AM, MSC, and control groups. AM infusion significantly inhibited apoptosis of transplanted MSCs. As a result, the number of engrafted MSCs in the MSC+AM group was significantly higher than that in the MSC group.

CONCLUSIONS

AM enhanced the therapeutic potency of MSCs, including neurological improvement, possibly through inhibition of MSC apoptosis and induction of angiogenesis.

Detection of 111In-oxine-labeled bone marrow stromal cells after intravenous or intralesional administration in chronic paraplegic rats

Recent studies suggested that bone marrow stromal cells (BMSC) may have a therapeutic role in the treatment of paraplegia secondary to severe spinal cord injury (SCI). For this reason, we have studied the possibility of using nuclear medicine imaging techniques to evaluate the permanency and migration of BMSC after transplantation procedures in chronic paraplegic Wistar rats. After intravenous administration of 111In-oxine-labeled BMSC, gammagraphic images showed that the activity distributed all over the organism, but in the spinal cord only scarce activity was identified. When 111In-oxine-labeled BMSC were injected within the traumatic centromedullary cavity of paraplegic animals, the gammagraphic images showed persistent activity in the lesion zone, without any activity migrating to the rest of the organism, at least during the whole time of the study (10 days after transplantation procedures). Our results show the utility of 111In labeling for to know the permanency and distribution of BMSC after grafting procedures, and suggest the convenience of the intralesional administration of BMSC, instead of the intravenous administration, in the treatment of chronic traumatic paraplegia.

Bone-marrow-derived cells contribute to the recruitment of microglial cells in response to β-amyloid deposition in APP/PS1 double transgenic Alzheimer mice

The role of microglia recruited from bone marrow (BM) into the CNS during the progression of Alzheimer's disease (AD) is poorly understood. To investigate whether beta-amyloid (Abeta) associated microglia are derived from blood monocytes, we transplanted BM cells from enhanced green fluorescent protein expressing mice into young or old transgenic AD mice and determined the engraftment of BM-derived cells into the brain and their relative distribution near Abeta deposits. When young transgenic mice were transplanted before the onset of AD-like pathology and the brains analyzed 6.5 months later, the number of engrafted cells was significantly higher than in age-matched wild type mice. Moreover, the number of BM-derived cells associated with Abeta was significantly higher than in old transgenic mice transplanted after the establishment of AD-like pathology. Local inflammation caused by intrahippocampal lipopolysaccharide injection significantly increased the engraftment of BM-derived cells in old AD mice and decreased the hippocampal Abeta burden. These results suggest that infiltration of BM-derived monocytic cells into the brain contributes to the development of microglial reaction in AD.

Expression of insulin-like growth factor 1 and receptor in ischemic rats treated with human marrow stromal cells

Human bone marrow stromal cells (hMSCs) enhance neurological recovery after stroke in rodents, possibly via induction of growth factors. We therefore elected to test the effects of hMSC treatment on insulin-like growth factor 1 (IGF-1), which plays an important role in growth, development, neuroprotection and repair in the adult. Rats (n=57) were subjected to permanent middle cerebral artery occlusion (MCAo) and injected intravenously with 3 x 10(6) hMSCs or phosphate-buffered saline (PBS) at 1 day after MCAo. Functional outcome was measured after MCAo using a modified Neurological Severity Score (mNSS). Gene expression of IGF-1 and IGF-1 receptor (IGF-1R) in the ischemic brain tissue were measured at 2 and 7 days after MCAo using reverse transcription-polymerase chain reaction (RT-PCR). Immunohistochemistry was performed to measure the expression of bromodeoxyuridine (BrdU), doublecortin (DCX), IGF-1 and IGF-1R at 7, 14 and 30 days after MCAo. Treatment of MCAo with hMSCs significantly improved functional recovery from 14 to 30 days. MAB1281-labeled hMSCs entered the ischemic brain and increased time-dependently. hMSC treatment significantly increased IGF-1 mRNA and BrdU(+), DCX(+), IGF-1(+) and IGF-1R(+) cells compared to PBS-treated rats (p<0.05). The percentage of BrdU(+) or DCX(+) cells colocalized with IGF-1 increased in the hMSC-treated rats compared to the PBS-treated rats (p<0.05). IGF-1 and IGF-1R may contribute to improved functional recovery and increased neurogenesis after treatment of stroke with hMSCs.

Mesenchymal stem cells and their potential as cardiac therapeutics

Mesenchymal stem cells (MSCs) represent a stem cell population present in adult tissues that can be isolated, expanded in culture, and characterized in vitro and in vivo. MSCs differentiate readily into chondrocytes, adipocytes, osteocytes, and they can support hematopoietic stem cells or embryonic stem cells in culture. Evidence suggests MSCs can also express phenotypic characteristics of endothelial, neural, smooth muscle, skeletal myoblasts, and cardiac myocyte cells. When introduced into the infarcted heart, MSCs prevent deleterious remodeling and improve recovery, although further understanding of MSC differentiation in the cardiac scar tissue is still needed. MSCs have been injected directly into the infarct, or they have been administered intravenously and seen to home to the site of injury. Examination of the interaction of allogeneic MSCs with cells of the immune system indicates little rejection by T cells. Persistence of allogeneic MSCs in vivo suggests their potential "off the shelf" therapeutic use for multiple recipients. Clinical use of cultured human MSCs (hMSCs) has begun for cancer patients, and recipients have received autologous or allogeneic MSCs. Research continues to support the desirable traits of MSCs for development of cellular therapeutics for many tissues, including the cardiovascular system. In summary, hMSCs isolated from adult bone marrow provide an excellent model for development of stem cell therapeutics, and their potential use in the cardiovascular system is currently under investigation in the laboratory and clinical settings.

Reevaluation of in vitro differentiation protocols for bone marrow stromal cells: disruption of actin cytoskeleton induces rapid morphological changes and mimics neuronal phenotype

Bone marrow stromal cells (MSC), which represent a population of multipotential mesenchymal stem cells, have been reported to undergo rapid and robust transformation into neuron-like phenotypes in vitro following treatment with chemical induction medium including dimethyl sulfoxide (DMSO; Woodbury et al. [2002] J. Neurosci. Res. 96:908). In this study, we confirmed the ability of cultured rat MSC to undergo in vitro osteogenesis, chondrogenesis, and adipogenesis, demonstrating differentiation of these cells to three mesenchymal cell fates. We then evaluated the potential for in vitro neuronal differentiation of these MSC, finding that changes in morphology upon addition of the chemical induction medium were caused by rapid disruption of the actin cytoskeleton. Retraction of the cytoplasm left behind long processes, which, although strikingly resembling neurites, showed essentially no motility and no further elaboration during time-lapse studies. Similar neurite-like processes were induced by treating MSC with DMSO only or with actin filament-depolymerizing agents. Although process formation was accompanied by rapid expression of some neuronal and glial markers, the absence of other essential neuronal proteins pointed toward aberrantly induced gene expression rather than toward a sequence of gene expression as is required for neurogenesis. Moreover, rat dermal fibroblasts responded to neuronal induction by forming similar processes and expressing similar markers. These studies do not rule out the possibility that MSC can differentiate into neurons; however, we do want to caution that in vitro differentiation protocols may have unexpected, misleading effects. A dissection of molecular signaling and commitment events may be necessary to verify the ability of MSC transdifferentiation to neuronal lineages.

Minimally invasive delivery of stem cells for spinal cord injury: advantages of the lumbar puncture technique

Object. Stem cell therapy has been shown to have considerable therapeutic potential for spinal cord injuries (SCIs); however, most experiments in animals have been performed by injecting cells directly into the injured parenchyma. This invasive technique compromises the injured spinal cord, although it delivers cells into the hostile environment of the acutely injured cord. In this study, the authors tested the possibility of delivering stem cells to injured spinal cord by using three different minimally invasive techniques.

Methods. Bone marrow stromal cells (BMSCs) are clinically attractive because they have shown therapeutic potential in SCI and can be obtained in patients at the bedside, raising the possibility of autologous transplantation. In this study transgenically labeled cells were used for transplantation, facilitating posttransplantation tracking. Inbred Fisher-344 rats received partial cervical hemisection injury, and 2 × 106 BMSCs were intravenously, intraventricularly, or intrathecally transplanted 24 hours later via lumbar puncture (LP). The animals were killed 3, 10, or 14 days posttransplantation, and tissue samples were submitted to histochemical and immunofluorescence analyses. For additional comparison and validation, lineage restricted neural precursor (LRNP) cells obtained from E13.5 rat embryos were transplanted via LP, and these findings were also analyzed.

Conclusions. Both BMSCs and LRNP cells home toward injured spinal cord tissues. The use of LP and intraventricular routes allows more efficient delivery of cells to the injured cord compared with the intravenous route. Stem cells delivered via LP for treatment of SCI may potentially be applicable in humans after optimal protocols and safety profiles are established in further studies.

The future of cell-based transplantation therapies for neurodegenerative disorders

Parkinson's disease is a common neurodegenerative disease with a lifetime incidence of 2.5% and a prevalence of at least 2% in individuals over 70 years old. Patients can be effectively treated with drugs that target the dopaminergic nigro-striatal pathway, but over time the efficacy of these medications is limited by the development of profound motor fluctuations and dyskinesias. This has prompted the search for alternative treatments, including the use of cell replacement therapies. Over the last decade, human fetal nigral transplants have demonstrated that dopaminergic neurons can survive and provide clinical benefit for patients with Parkinson's disease. However, there are clearly ethical concerns and a limit to the supply of this tissue as well as more recently anxieties over side effects. As a result, alternative sources of tissue have been investigated, and one such source are stem cells, which provide an attractive renewable tissue supply. In this review, we will discuss the current state-of-the-art and the characteristics of Parkinson's disease that increase its attraction as a target of stem cell therapy against results of current clinical trials using fetal neural grafts. Then we will discuss the various types and sources of stem cells, and some early transplantation results in animal models of Parkinson's disease. Finally we will discuss the prospect of using stem cells to deliver drugs and neurotrophic factors involved in neuroprotective and neuroreparative strategies in Parkinson's disease and other neurodegenerative conditions.

Is there a future for neural transplantation?

Traditionally neural transplantation has had as its central tenet the replacement of missing neurons that have been lost because of neurodegenerative processes, as exemplified by diseases such as Parkinson disease (PD). However, the effectiveness and widespread application of this approach clinically has been limited, primarily because of the poor donor supply of human fetal neural tissue and the incomplete neurobiological understanding of the circuit reconstruction required to normalize function in these diseases. So, in PD the progress from promising neural transplantation in animal models to proof-of-principle, open-labeled clinical transplants, to randomized, placebo-controlled studies of neural transplantation has not been straightforward. The emergence of previously undescribed adverse effects and lack of significant functional advantage in recent clinical studies has been disappointing and has served to cast a new, and perhaps more realistic, perspective on this treatment approach. In fact, there have been calls by some involved in neural transplantation to return to the drawing board before pressing on with further clinical trials, and the return to basic experimentation. This therefore precipitates the question - is there a future for neural transplantation? It is important to remember that there are a number of possible explanations for the disappointing results from the recent clinical trials in PD, ranging from the mode of transplantation to patient selection. Nevertheless, almost irrespective of these reasons for the current trial results, there have always been significant practical and ethical problems with using human fetal tissue, and so a number of alternative cell sources have been investigated. These alternative sources include stem cells, which are attractive for cell-based therapies because of their potential ease of isolation, propagation and manipulation, and their ability in some cases to migrate to areas of pathology and differentiate into specific and appropriate cell types. Furthermore, the availability of stem cells derived from non-embryonic sources (e.g. adult stem cells derived from the sub-ventricular zone) has removed some of the ethical limitations associated with the use of embryonic human tissue. These potentially beneficial aspects of stem cells means that there is a future for neural transplantation as a means of treating patients with a range of neurological disorders, although whether this will ever translate into a truly effective, widely available therapy remains unknown.

Intravenously injected neural progenitor cells of transgenic rats can migrate to the injured spinal cord and differentiate into neurons, astrocytes and oligodendrocytes

Transplantation of neural progenitor cells (NPCs) has been reported recently to promote regeneration of the injured spinal cord. In the majority of these reports, cell transplantation was performed by local injection with a needle. However, direct injection might be too invasive for clinical use; therefore, the authors investigated a new method of delivering NPCs for the treatment of spinal cord injury. In this study, NPCs were obtained from E15 fetal hippocampus of transgenic rats expressing green fluorescent protein and 100,000 cells were transplanted intravenously into each animal 24h after contusion injury. It was found that the injected NPCs migrated to the lesion site widely and demonstrated nestin at an early phase after transplantation. These NPCs differentiated into neurons, astrocytes and oligodendrocytes, and survived at least for 56 days. These results indicated that intravenously injected neural stem cells migrated into the spinal cord lesion while preserving their potential as NPCs, and that this procedure is a potential method of delivering cells into the lesion for the treatment of spinal cord injury.

Adult stem cells--reprogramming neurological repair?

Much excitement has surrounded recent breakthroughs in embryonic stem-cell research. Of lower profile, but no less exciting, are the advances in the field of adult stem-cell research, and their implications for cell therapy. Clinical experience from use of adult haemopoietic stem cells in haematology will facilitate and hasten transition from laboratory to clinic--indeed, clinical trials using adult human stem cells are already in progress in some disease states, including myocardial ischaemia. Here, with particular reference to neurology, we review processes that might underlie apparent changes in adult cell phenotype. We discuss implications these processes might have for the development of new therapeutic strategies using adult stem cells.

Functional recovery in chronic paraplegia after bone marrow stromal cells transplantation

Previous reports showed the therapeutic effect of transplants of bone marrow stromal cells (BMSC) after incomplete traumatic spinal cord lesions. We studied the effect of this form of therapy in chronically paraplegic Wistar rats due to severe spinal cord injury (SCI). Rats were subjected to weight-drop impact causing paraplegia, and BMSC or phosphate buffered saline (PBS) was injected into spinal cord 3 months after injury. Functional outcome was measured using the Basso-Beattie-Bresnehan score until sacrifice of the animals, 4 weeks after transplantation. At this time, samples of spinal cord tissue were studied histologically. The results showed a clear and progressive functional recovery of the animals treated with BMSC transplantation, compared to controls. Grafted BMSC survived into spinal cord tissue, forming cell bridges within the traumatic centromedullary cavity. In this tissue, cells expressing neuronal and astroglial markers can be seen, together with a marked ependymal proliferation, showing nestin-positivity. These findings suggest the utility of BMSC transplantation in chronically established paraplegia.

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.

Biologic Transplantation and Neurotrophin-Induced Neuroplasticity After Traumatic Brain Injury

OBJECTIVE

In this review, we analyze progress in the treatment of traumatic brain injury with neurotrophins, growth factors and cell and tissue neurotransplantation. The primary objective of these therapies is to reduce neurologic deficits associated with the trauma by inducing neuroplasticity. These therapies are restorative and not necessarily neuroprotective.

MAIN OUTCOME MEASURES

An extensive literature on administration of neurotrophics factors and cell and tissue cerebral transplantation is reviewed. The effects of these therapeutic approaches on brain biochemical, molecular, cellular, and tissue responses are summarized.

CONCLUSION

The cumulative data indicate that cell therapy shows substantial promise in the treatment of neural injury.

Injection of adult neurospheres induces recovery in a chronic model of multiple sclerosis

Widespread demyelination and axonal loss are the pathological hallmarks of multiple sclerosis. The multifocal nature of this chronic inflammatory disease of the central nervous system complicates cellular therapy and puts emphasis on both the donor cell origin and the route of cell transplantation. We established syngenic adult neural stem cell cultures and injected them into an animal model of multiple sclerosis--experimental autoimmune encephalomyelitis (EAE) in the mouse--either intravenously or intracerebroventricularly. In both cases, significant numbers of donor cells entered into demyelinating areas of the central nervous system and differentiated into mature brain cells. Within these areas, oligodendrocyte progenitors markedly increased, with many of them being of donor origin and actively remyelinating axons. Furthermore, a significant reduction of astrogliosis and a marked decrease in the extent of demyelination and axonal loss were observed in transplanted animals. The functional impairment caused by EAE was almost abolished in transplanted mice, both clinically and neurophysiologically. Thus, adult neural precursor cells promote multifocal remyelination and functional recovery after intravenous or intrathecal injection in a chronic model of multiple sclerosis.

The therapeutic effects of cellular therapy for functional recovery after brain injury

The studies presented in this article suggest that marrow-derived cellular therapy may be an effective adjunct treatment for functional recovery after stroke. Cellular therapy can enhance the endogenous restorative mechanisms of the injured brain, assisting the tissue as it returns to a "developmental" state and supporting the process of neovascularization, neurogenesis, and neural reorganization. The advantages of using MSCs are that they can be given as an autologous graft, avoiding risks of rejection and graft-versus-host reactions, and that they can be given intravenously, minimizing complications. It is anticipated that cellular therapy, in combination with standard rehabilitation therapy and neural retraining, can improve functional outcomes following stroke.