CD133 cells from human umbilical cord blood reduce cortical damage and promote axonal growth in neonatal rat organ co-cultures exposed to hypoxia

To evaluate the effect of CD133⁺ cells (endothelial progenitor cells) on the hypoxia-induced suppression of axonal growth of cortical neurons and the destruction of blood vessels (endothelial cells), we used anterograde axonal tracing and immunofluorescence in organ co-cultures of the cortex and the spinal cord from 3-day-old neonatal rats. CD133⁺ cells prepared from human umbilical cord blood were added to the organ co-cultures after hypoxic insult, and axonal growth, vascular damage and apoptosis were evaluated. Anterograde axonal tracing with 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate was used to analyze axonal projections from the cortex to the spinal cord. Immunolabeling co-cultured tissues of the cortex and the spinal cord were used to investigate the effect of CD133⁺ cells on the survival of blood vessels and apoptosis in the brain cortex. Hypoxia remarkably suppressed axonal growth in organ co-cultures of the cortex and the spinal cord, and this suppression was significantly restored by the addition of CD133⁺ cells. CD133⁺ cells also reduced the hypoxia-induced destruction of the cortical blood vessels and apoptosis. CD133⁺ cells had protective effects on hypoxia-induced injury of neurons and blood vessels of the brain cortex in vitro. These results suggest that CD133⁺ cell transplantation may be a possible therapeutic intervention for perinatal hypoxia-induced brain injury.     

Human platelet-rich plasma promotes axon growth in brain-spinal cord coculture

Platelet-rich plasma (PRP) contains several growth factors, including platelet-derived growth factor (PDGF), transforming growth factor-β1 (TGF-β1), insulin-like growth factor-1 (IGF-1), and vascular endothelial growth factor (VEGF), that are associated with repair processes after central nervous system injury. Although PRP have been applied to some regenerative therapies, the regeneration effects of PRP on spinal cord injury have not been reported. This study applied a rat organ coculture system to examine the ability of PRP to enhance axonal growth in spinal cord tissues and to identify the growth factors in PRP that contribute to the regulation of axon growth. PRP from human peripheral blood was added to organ cocultures. Furthermore, neutralizing antibodies against PDGF-AB, TGF-β1, IGF-1, or VEGF were added to the cocultures with PRP. Axon growth from the brain cortex into the spinal cord was assessed quantitatively using anterograde axon tracing with DiI. Addition of PRP to the cocultures promoted axon growth, and the axon growth was significantly suppressed by the addition of neutralizing antibodies against IGF-1 and VEGF, but not PDGF-AB. In contrast, axon growth was promoted significantly by the addition of neutralizing antibodies against TGF-β1. These findings indicate that PRP promotes axon growth in spinal cord tissues through mechanisms associated with IGF-1 and VEGF, and that TGF-β1 in PRP exerts negative effects on axon growth.     

Correction of humoral derangements from mutant superoxide dismutase 1 spinal cord

OBJECTIVE: We sought to define molecular and cellular participants that mediate motor neuron injury in amyotrophic lateral sclerosis using a coculture system. METHODS: We cocultured embryonic stem cell-derived motor neurons with organotypic slice cultures from wild-type or SOD1G93A (MT) mice. We examined axon lengths and cell survival of embryonic stem cell-derived motor neurons. We defined and quantified the humoral factors that differed between wild-type and MT organotypic cultures, and then corrected these differences in cell culture. RESULTS: MT spinal cord organotypic slices were selectively toxic to motor neurons as defined by axonal lengths and cell survival. MT spinal cord organotypic slices secreted higher levels of nitric oxide, interleukin (IL)-1beta, IL-6, and IL-12p70 and lower levels of vascular endothelial growth factor. The toxicity of MT spinal cord organotypic cultures was reduced and axonal lengths were restored to near normal by coculturing in the presence of reactive oxygen species scavenger, vascular endothelial growth factor, and neutralizing antibodies to IL-1beta, IL-6, and IL-12. INTERPRETATION: MT spinal cord organotypic cultures overexpress certain factors and underexpress others, creating a nonpermissive environment for cocultured motor neurons. Correction of these abnormalities as a group, but not individually, restores axonal length to near normal. Such a "cocktail" approach to the treatment of amyotrophic lateral sclerosis should be investigated further.     

Transplantation of an adipose stem cell cluster in a spinal cord injury

We investigated whether transplantation of a three-dimensional cell mass of adipose-derived stem cells (3DCM-ASCs) improved hind limb functional recovery by the stimulation of angiogenesis and neurogenesis in a spinal cord injury. In in-vitro experiments, we confirmed that 3DCM-ASCs differentiated into CD31-positive endothelial cells. To evaluate the therapeutic effect of 3DCM-ASCs in vivo, PBS, human adipose tissue-derived stem cells, and 3DCM-ASCs were transplanted into a spinal cord injury model. The 3DCM-ASCs transplanted into the injured spinal cord differentiated into CD31-positive endothelial cells and remained differentiated. Transplantation of 3DCM-ASCs into the injured spinal cord significantly elevated the density of vascular formations through angiogenic factors released by the 3DCM-ASCs at the lesion site, and enhanced axonal outgrowth at the lesion site. Consistent with these results, the transplantation of 3DCM-ASCs significantly improved functional recovery compared with both ASC transplantation and PBS treatment. These findings suggest that transplantation of 3DCM-ASCs may be an effective stem cell therapy for the treatment of spinal cord injuries and neural ischemia.     

Cellular composition of long-term human spinal cord- and forebrain-derived neurosphere cultures

In vitro expanded neural precursor cells (NPCs) may provide a stable source for cell therapy. In search of the optimal cell source for spinal cord repair, we investigated influences of gestational age, regional heterogeneity, and long-term in vitro propagation. The cellular content of neurosphere cultures prior to and after in vitro differentiation was studied by immunocytochemistry and flow cytometry. Human forebrain and spinal cord NPCs deriving from first-trimester tissue were cultured as neurospheres in the presence of epidermal growth factor, basic fibroblast growth factor, and ciliary neurotrophic factor. Proteins characteristic for embryonic stem cells, i.e., Tra-1-60, Tra-1-81, and SSEA-4, were present in approximately 0.5% of the cells in donor tissues and neurospheres. The proportions of nestin- and proliferating cell nuclear antigen-immunoreactive (IR) cells were also maintained, whereas the CD133-IR population increased in vitro. Glial fibrillary acidic protein-IR cells increased in number, and in contrast the fraction of beta-tubulin III-IR cells decreased, at and beyond passage 5 in spinal cord but not forebrain cultures. However, dissociated and in vitro-differentiated forebrain- and spinal cord-derived neurospheres generated similar proportions of neurons, astrocytes, and oligodendrocytes. Gestational age of the donor tissue, which ranged from 4.5 to 12 weeks for forebrain and from 4.5 to 9.5 weeks for spinal cord, did not affect the proportion of cells with different phenotypes in culture. Thus, cellular composition of human neurosphere cultures differs as a result of long-term in vitro propagation and regional heterogeneity of source tissue, despite expansion under equal culture conditions. This could in turn imply that human spinal cord and forebrain NPCs present different repair potentials in in vivo settings.     

Enhancement of neovascularization with cord blood CD133+ cell-derived endothelial progenitor cell transplantation

The endothelial progenitor cells (EPCs) are responsible for postnatal vasculogenesis in physiological and pathological neovascularization and have been used for attenuating ischemic diseases. However, EPCs from umbilical cord blood (CB) were not well understood and the homing mechanisms of EPCs remain unclear. To determine the potential application of CB-derived EPCs, we established a culture system to induce the differentiation of CB cells into EPCs. Purified CB CD133(+) cells proliferated and, after further vascular endothelial growth factor receptor 2 (VEGFR-2) antibody purification, differentiated into EPCs expressing endothelial markers, such as VE-cadherin, VEGFR-2, CD31, von Willebrand factor (vWF) and Weibel-Palade bodies. These cells could also take up acetylated lower density lipoprotein (Ac-LDL) and bind Ulex europaeus agglutinin-1 (UEA-1).When expanded EPCs were transplanted via tail vein into nude mice, they incorporated into capillary networks in ischemic hindlimb, augmented neovascularization, and improved ischemic limb salvage. In addition, in ischemic tissue, there were elevated expressions of VEGF and stromal derived factor 1 alpha (SDF-1 alpha), both of which had chemotactic effect on EPCs. Moreover, P-/E-selectins was found on mouse ischemic endothelium and P-selectin glycoprotein ligand-1 (PSGL-1) on CB-derived EPCs. Neutralizing antibody against PSGL-1 blocked the homing of EPCs to ischemic area by 61%. These results demonstrate that CB CD133(+) cell-derived EPCs can be applied for therapeutic neovascularization in ischemic diseases, and reveal important roles of chemoattractants and adhesive molecules in the homing of EPCs.     

Human skin-derived stem cells migrate throughout forebrain and differentiate into astrocytes after injection into adult mouse brain

Recent evidence indicates that neural stem cell properties can be found among a mammalian skin-derived multipotent population. A major barrier in the further characterization of the human skin-derived neural progenitors is the inability to isolate this population based on expression of cell surface markers. Our work has been devoted to purified human skin-derived stem cells that are capable of neural differentiation, based on the presence or absence of the AC133 cell surface marker. The enriched skin-derived AC133(+) cells express the CD34 and Thy-1 antigens. These cells cultured in a growth medium containing epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) proliferate, forming spheres, and differentiate in vitro into neurons, astrocytes, and rarely into oligodendrocytes. Single cells from sphere cultures initiated from human purified AC133(+) cells were replated as single cells and were able to generate new spheres, demonstrating the self-renewing ability of these stem cell populations. Brain engraftment of cells obtained from human purified AC133(+)-derived spheres generated different neural phenotypes: immature neurons and a most abundant population of well differentiated astrocytes. The AC133-derived astrocytes assumed perivascular locations in the frontal cortex. No donor-derived oligodendrocytes were found in the transplanted mouse brains. Several donor small, rounded cells that expressed endothelial markers were found close to the host vessel and near the subventricular zone. Thus, mammalian skin AC133-derived cells behave as a multipotent population with the capacity to differentiate into neural lineages in vitro and, prevalently, endothelium and astrocytes in vivo, demonstrating the great plasticity of these cells and suggesting potential clinical application.     

Neural progenitor cells promote corticospinal axon growth in organotypic co-cultures

The CNS is limited in regeneration following injury in adult mammals. Recent studies show that the transplantation of the neuronal progenitor cells is useful in promoting regeneration. However, the mechanisms of action of the transplanted neural progenitor cells have not been clarified. In this study, we used organotypic co-cultures with neonatal brain cortex and spinal cord as an in vitro assay system for assessing the factors that regulate corticospinal axonal growth. Our results show that the transplantation of neural progenitor cells enhanced corticospinal axon growth in these co-cultures. In addition, neural progenitor cell conditioned medium also significantly promoted axonal growth. These findings strongly suggest that factors derived from neural progenitor cells participate in the effect on axonal growth.     

Brain and spinal cord affected by amyotrophic lateral sclerosis induce differential growth factors expression in rat mesenchymal and neural stem cells

C. Nicaise, D. Mitrecic and R. Pochet (2011) Neuropathology and Applied Neurobiology 37, 179–188
Brain and spinal cord affected by amyotrophic lateral sclerosis induce differential growth factors expression in rat mesenchymal and neural stem cells Stem cell research raises hopes for incurable neurodegenerative diseases. In amyotrophic lateral sclerosis (ALS), affecting the motoneurones of the central nervous system (CNS), stem cell‐based therapy aims to replace dying host motoneurones by transplantation of cells in disease‐affected regions. Moreover, transplanted stem cells can serve as a source of trophic factors providing neuroprotection, slowing down neuronal degeneration and disease progression. Aim: To determine the profile of seven trophic factors expressed by mesenchymal stem cells (MSC) and neural stem cells (NSC) upon stimulation with CNS protein extracts from SOD1‐linked ALS rat model. Methods: Culture of rat MSC, NSC and fibroblasts were incubated with brain and spinal cord extracts from SOD1(G93A) transgenic rats and mRNA expression of seven growth factors was measured by quantitative PCR. Results: MSC, NSC and fibroblasts exhibited different expression patterns. Nerve growth factor and brain‐derived neurotropic factor were significantly upregulated in both NSC and MSC cultures upon stimulation with SOD1(G93A) CNS extracts. Fibroblast growth factor 2, insulin‐like growth factor and glial‐derived neurotropic factor were upregulated in NSC, while the same factors were downregulated in MSC. Vascular endothelial growth factor A upregulation was restricted to MSC and fibroblasts. Surprisingly, SOD1(G93A) spinal cord, but not the brain extract, upregulated brain‐derived neurotropic factor in MSC and glial‐derived neurotropic factor in NSC. Conclusions: These results suggest that inherent characteristics of different stem cell populations define their healing potential and raise the concept of ALS environment in stem cell transplantation.     

Growth of corticospinal axons on prosthetic substrates introduced into the spinal cord of neonatal rats

Nitrocellulose implants treated with biological materials known to support neurite growth in vitro were introduced at thoracolumbar levels of the neonatal rat spinal cord before the arrival of growing corticospinal tract (CST) axons. Implant placement was designed to interrupt the normal CST growth path and provide a potential, alternative growth path. Subsequent growth of CST axons within the spinal cord in the vicinity of the implants was evaluated by labeling the axons with the anterograde transport of horseradish peroxidase. Untreated implants either blocked further CST axon growth or deflected CST axons to abnormal positions. Implants bearing living cells from spinal cord primary cultures were able to support the adhesion and growth of CST axons. Similarly, acellular implants coated with laminin, but not with poly-L-lysine supported the adhesion and growth of CST axons, suggesting that laminin or some other adhesive factor produced by immature neuroglial cells may be normally involved in CST axon growth and guidance.     

Secretion of nerve growth factor,brain-derived neurotrophic factor,and glial cell-line derived neurotrophic factor in co-culture of four cell types in cerebrospinal fluid-containing medium

The present study co-cultured human embryonic olfactory ensheathing cells, human Schwann cells, human amniotic epithelial cells and human vascular endothelial cells in complete culture medium- containing cerebrospinal fluid. Enzyme linked immunosorbent assay was used to detect nerve growth factor, brain-derived neurotrophic factor, and glial cell line-derived neurotrophic factor secretion in the supernatant of co-cultured cells. Results showed that the number of all cell types reached a peak at 7-10 days, and the expression of nerve growth factor, brain-derived neurotrophic factor, and glial cell line-derived neurotrophic factor peaked at 9 days. Levels of secreted nerve growth factor were four-fold higher than brain-derived neurotrophic factor, which was three-fold higher than glial cell line-derived neurotrophic factor. Increasing concentrations of cerebrospinal fluid (10%, 20% and 30%) in the growth medium caused a decrease of neurotrophic factor secretion Results indicated co-culture of human embryonic olfactory ensheathing cells, human Schwann cells human amniotic epithelial cells and human vascular endothelial cells improved the expression of nerve growth factor, brain-derived neurotrophic factor, and glial cell line-derived neurotrophic factor. The reduction of cerebrospinal fluid extravasation at the transplant site after spinal cord injury is beneficial for the survival and secretion of neurotrophic factors from transplanted cells.     

Introduction of the MASH1 gene into mouse embryonic stem cells leads to differentiation of motoneuron precursors lacking Nogo receptor expression that can be applicable for transplantation to spinal cord injury

ES cells transfected with the MASH1 gene yielded purified spinal motoneuron precursors expressing HB9 and Islet1. The cells lacked the expression of Nogo receptor that was of great advantage for axon growth after transplantation to an injured spinal cord. After transplantation, mice with the complete transection of spinal cord exhibited excellent improvement of the motor functions. Electrophysiological assessment confirmed the quantitative recovery of motor-evoked potential in the transplanted spinal cord. In the grafted spinal cord, gliosis was inhibited and Nogo receptor expression was scarcely detected. The transplanted cells labeled with GFP showed extensive outgrowth of axons positive for neurofilament middle chain, connected to each other and expressed Synaptophysin, Lim1/2 and Islet1. Thus, the in vivo differentiation into mature spinal motoneurons and the reconstitution of neuronal pathways were suggested. The grafted cell population was purified for neurons and was free from teratoma development. These therapeutic strategies may contribute to a potent treatment for spinal cord injury in future.     

Stage of specification of the spinal cord and tectal projections from cortical grafts

In order to determine the embryonic age at which the hodological phenotype developed by neocortical cells is specified, we have examined the spinal or tectal projections developed by embryonic (E) grafts of presumptive frontal or occipital neocortex placed into the frontal or occipital neocortex of newborn host rats. Grafts of E13, E14 and E16 cells of the frontal cortex transplanted into the occipital cortex of newborns are capable of developing and maintaining in adulthood a spinal cord axon. Grafts of E12 cells do not project to the spinal cord but send fibres to the superficial layers of the tectum. In addition, following transplantation into the frontal cortex, early embryonic (E12) cells from the presumptive occipital cortex are capable of differentiating into neurons with spinal cord projection but are practically incapable of developing a tectal projection. When grafted at E14 into the frontal cortex, occipital cells lose the capacity to project to the spinal cord but become able to send fibres to the tectum. Taken together, these findings indicate that young (E12) embryonic frontal and occipital cortical cells are competent to subsequently differentiate into neurons projecting to the spinal cord or tectum according to instructive signals available in the cortical territory where they complete their development. By E13/E14, some cortical cells are specified and their capacity to contact targets that are not appropriate to their embryonic origin is much reduced. These findings are consistent with the notion that cortical specification involves progressive restriction in cell multipotentiality and fate specification toward region-specific phenotypes.     

MicroRNA miR-133b is essential for functional recovery after spinal cord injury in adult zebrafish

MicroRNAs (miRNAs) play important roles during development and also in adult organisms by regulating the expression of multiple target genes. Here, we studied the function of miR-133b during zebrafish spinal cord regeneration and show upregulation of miR-133b expression in regenerating neurons of the brainstem after transection of the spinal cord. miR-133b has been shown to promote tissue regeneration in other tissue, but its ability to do so in the nervous system has yet to be tested. Inhibition of miR-133b expression by antisense morpholino (MO) application resulted in impaired locomotor recovery and reduced regeneration of axons from neurons in the nucleus of the medial longitudinal fascicle, superior reticular formation and intermediate reticular formation. miR-133b targets the small GTPase RhoA, which is an inhibitor of axonal growth, as well as other neurite outgrowth-related molecules. Our results indicate that miR-133b is an important determinant in spinal cord regeneration of adult zebrafish through reduction in RhoA protein levels by direct interaction with its mRNA. While RhoA has been studied as a therapeutic target in spinal cord injury, this is the first demonstration of endogenous regulation of RhoA by a microRNA that is required for spinal cord regeneration in zebrafish. The ability of miR-133b to suppress molecules that inhibit axon regrowth may underlie the capacity for adult zebrafish to recover locomotor function after spinal cord injury.     

EphA4 regulates central nervous system vascular formation

Molecules involved in axon guidance have recently also been shown to play a role in blood vessel guidance. To examine whether axon guidance molecules, such as the EphA4 receptor tyrosine kinase, might also play a role in development of the central nervous system (CNS) vasculature and repair following CNS injury, we examined wild-type and EphA4 null mutant (-/-) mice. EphA4-/- mice exhibited an abnormal CNS vascular structure in both the cerebral cortex and the spinal cord, with disorganized branching and a 30% smaller diameter. During development, EphA4 was expressed on endothelial cells. This pattern of expression was not maintained in the adult. After spinal cord injury in wild-type mice, expression of EphA4 was markedly up-regulated on activated astrocytes, many of which were tightly associated with blood vessels. In EphA4-/- spinal cord following injury, astrocytes were not as tightly associated with blood vessels as the wild-type astrocytes. In uninjured EphA4-/- mice, the blood-brain barrier (BBB) appeared normal, but it showed prolonged leakage following spinal cord injury. These results support a role for EphA4 in CNS vascular formation and guidance during development and an additional role in BBB repair.     

Response of the sensorimotor cortex of cerebral palsy rats receiving transplantation of vascular endothelial growth factor 165-transfected neural stem cells

Neural stem cells are characterized by the ability to differentiate and stably express exogenous ge- nes. Vascular endothelial growth factor plays a role in protecting local blood vessels and neurons of newborn rats with hypoxic-ischemic encephalopathy. Transplantation of vascular endothelial growth factor-transfected neural stem cells may be neuroprotective in rats with cerebral palsy. In this study, 7-day-old Sprague-Dawley rats were divided into five groups： （1） sham operation （control）, （2） cerebral palsy model alone or with （3） phosphate-buffered saline, （4） vascular en- dothelial growth factor 165 ＋ neural stem cells, or （5） neural stem cells alone. The cerebral palsy model was established by ligating the left common carotid artery followed by exposure to hypox- ia. Phosphate-buffered saline, vascular endothelial growth factor ＋ neural stem cells, and neural stem cells alone were administered into the sensorimotor cortex using the stereotaxic instrument and microsyringe. After transplantation, the radial-arm water maze test and holding test were performed. Immunohistochemistry for vascular endothelial growth factor and histology using hematoxylin-eosin were performed on cerebral cortex. Results revealed that the number of vas- cular endothelial growth factor-positive cells in cerebral palsy rats transplanted with vascular endothelial growth factor-transfected neural stem cells was increased, the time for finding water and the finding repetitions were reduced, the holding time was prolonged, and the degree of cell degeneration or necrosis was reduced. These findings indicate that the transplantation of vascu- lar endothelial growth factor-transfected neural stem cells alleviates brain damage and cognitive deficits, and is neuroprotective in neonatal rats with hypoxia ischemic-mediated cerebral palsy.     

VEGF mRNA Induction Correlates With Changes in the Vascular Architecture Upon Spinal Cord Damage in the Rat

The multiple cellular and molecular processes induced by injury to the central nervous system (CNS) are still poorly understood. In the present study, we investigated the response of the vasculature and the expression of mRNA for the angiogenic vascular endothelial growth factor (VEGF) following X-irradiation of the spinal cord in the newborn and following traumatic spinal cord injury in the adult rat. Both lesion models induced changes in the density and the distribution pattern of blood vessels: while X-irradiation led to a permanent local increase in vascular density in the fibre tracts of the exposed segments, a transient local sprouting of vessels was induced upon traumatic spinal cord injury. In situ hybridization showed that an increase of VEGF mRNA anticipated and overlapped with the vascular responses in both lesion models. In addition to the temporal correlation of VEGF expression and vascular sprouting, there was a clear correlation in the spatial distribution patterns. Following X-irradiation, the expression of VEGF mRNA was restricted to the fibre tracts, precisely the areas where the changes in the vasculature were observed later on. Upon transection in the adult animal, VEGF was mainly detectable at the border of the lesion area, where the transient increase in vascular density could be observed. Interestingly, according to the type of lesion applied, astrocytes (X-irradiation) or inflammatory cells (presumably microglial cells or macrophages; traumatic lesion) are the cellular sources of VEGF mRNA. Our results strongly indicate that VEGF is crucially involved in mediating vascular changes following different types of injury in the CNS.     

Presence of endothelial progenitor cells, distinct from mature endothelial cells, within human CD146+ blood cells

CD146 is an adhesion molecule present on endothelial cells throughout the vascular tree. CD146 is also expressed by circulating endothelial cells (CECs) widely considered to be mature endothelial cells detached from injured vessels. The discovery of circulating endothelial progenitor cells (EPCs) originating from bone marrow prompted us to investigate whether CD146 circulating cells could also contains EPCs. We tested this hypothesis using an approach combining elimination of CECs by an adhesion step, followed by immunomagnetic sorting of remaining CD146+ cells from the non adherent fraction of cord blood mononuclear cells. When cultured under endothelial-promoting conditions, these cells differentiated as late outgrowth endothelial colonies: they grew as a cobblestone monolayer, were uniformly positive for endothelial markers and did not express leukocyte antigens. They highly proliferated and were expanded in long-term culture without alterations of their phenotypic and functional properties (Dil-ac-LDL uptake, wound repair, capillary-like network formation, and TNFalpha response). Moreover, these cells colonized a Matrigel plug in immunodeficient mice (NOD/SCID). Finally, using 4-color flow cytometry analysis of purified CD34+ cells, we clearly discriminated, CD146+ EPCs (CD146+ CD34+ CD45+ CD133+ or CD117+), and CD146+ CECs (CD146+ CD34+, CD45- CD133- or CD117-), both in cord and adult peripheral blood.The relative proportions of the two CD146+ subsets varied in patients with myocardial infarction as compared to healthy subjects. Our study establishes that, beside CECs, CD146+ circulating cells contain a subpopulation of EPCs with potential use in proangiogenic therapy. In addition, the dual measurement of CD146+ CECs and CD146+ EPCs offers a promising tool for monitoring vascular injury/regeneration processes in clinical situations.     

Rapid recovery of tissue hypoxia by cotransplantation of endothelial cells

Disruption of blood vessels caused by a spinal cord injury leads to tissue hypoxia. This hypoxic condition reduces the survival of transplanted stem cells, consequentially decreasing the effectiveness of stem cell therapy. In this study, we investigated the correlation between angiogenesis and the survival of transplanted neural stem cells in a spinal cord injury model. Hypoxia-specific luciferase-expressing neural stem cells (EpoSV-Luc NSC) were used as a tool for the detection of hypoxia caused by a spinal cord injury. In vivo, angiogenesis by cotransplantation of endothelial cells quickly recovered tissue hypoxia caused by a spinal cord injury. As a result, cotransplantation of endothelial cells improved the survival of neural stem cells transplanted into the injured spinal cord.