Novel cell therapy approaches for brain repair

Near Infrared (NIR) Light Therapy of Eye Diseases: A Review

Near infrared (NIR) light therapy, or photobiomodulation therapy (PBMT), has gained persistent worldwide attention in recent years as a new novel scientific approach for therapeutic applications in ophthalmology. This ongoing therapeutic adoption of NIR therapy is largely propelled by significant advances in the fields of photobiology and bioenergetics, such as the discovery of photoneuromodulation by cytochrome c oxidase and the elucidation of therapeutic biochemical processes. Upon transcranial delivery, NIR light has been shown to significantly increase cytochrome oxidase and superoxide dismutase activities which suggests its role in inducing metabolic and antioxidant beneficial effects. Furthermore, NIR light may also boost cerebral blood flow and cognitive functions in humans without adverse effects. In this review, we highlight the value of NIR therapy as a novel paradigm for treatment of visual and neurological conditions, and provide scientific evidence to support the use of NIR therapy with emphasis on molecular and cellular mechanisms in eye diseases.

A Combination of Intrathecal and Intramuscular Application of Human Mesenchymal Stem Cells Partly Reduces the Activation of Necroptosis in the Spinal Cord of SOD1G93A Rats

An increasing number of studies have demonstrated the beneficial effects of human mesenchymal stem cells (hMSC) in the treatment of amyotrophic lateral sclerosis (ALS). We compared the effect of repeated intrathecal applications of hMSC or their conditioned medium (CondM) using lumbar puncture or injection into the muscle (quadriceps femoris), or a combination of both applications in symptomatic SOD1^G93A rats. We further assessed the effect of the treatment on three major cell death pathways (necroptosis, apoptosis, and autophagy) in the spinal cord tissue. All the animals were behaviorally tested (grip strength test, Basso Beattie Bresnahan (BBB) test, and rotarod), and the tissue was analyzed immunohistochemically, by qPCR and Western blot. All symptomatic SOD1 rats treated with hMSC had a significantly increased lifespan, improved motor activity and reduced number of Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) positive cells. Moreover, a combined hMSC delivery increased motor neuron survival, maintained neuromuscular junctions in quadriceps femoris and substantially reduced the levels of proteins involved in necroptosis (Rip1, mixed lineage kinase‐like protein, cl‐casp8), apoptosis (cl‐casp 9) and autophagy (beclin 1). Furthermore, astrogliosis and elevated levels of Connexin 43 were decreased after combined hMSC treatment. The repeated application of CondM, or intramuscular injections alone, improved motor activity; however, this improvement was not supported by changes at the molecular level. Our results provide new evidence that a combination of repeated intrathecal and intramuscular hMSC applications protects motor neurons and neuromuscular junctions, not only through a reduction of apoptosis and autophagy but also through the necroptosis pathway, which is significantly involved in cell death in rodent SOD1^G93A model of ALS. stem cells translational medicine2019;8:535–547

Insights into cell-free therapeutic approach: Role of stem cell "soup-ernatant"

Current advances in medicine have revolutionized the field of regenerative medicine dramatically with newly evolved therapies for repair or replacement of degenerating or injured tissues. Stem cells (SCs) can be harvested from different sources for clinical therapeutics, which include fetal tissues, umbilical cord blood, embryos, and adult tissues. SCs can be isolated and differentiated into desired lineages for tissue regeneration and cell replacement therapy. However, several loopholes need to be addressed properly before this can be extended for large-scale therapeutic application. These include a careful approach for patient safety during SC treatments and tolerance of recipients. SC treatments are associated with a number of risk factors and require successful integration and survival of transplanted cells in the desired microenvironment with concurrent tissue regeneration. Recent studies have focused on developing alternatives that can replace the cell-based therapy using paracrine factors. The development of stem "cell free" therapies can be devoted mainly to the use of soluble factors (secretome), extracellular vesicles, and mitochondrial transfer. The present review emphasizes on the paradigms related to the use of SC-based therapeutics and the potential applications of a cell-free approach as an alternative to cell-based therapy in the area of regenerative medicine.

Transplantation of Hematopoietic Stem Cells Promotes Functional Improvement Associated with NT-3-MEK-1 Activation in Spinal Cord-Transected Rats

Transected spinal cord injury (SCT) is a devastating clinical disease that strongly affects a patient’s daily life and remains a great challenge for clinicians. Stem-cell therapy has been proposed as a potential therapeutic modality for SCT. To investigate the effects of hematopoietic stem cells (HSCs) on the recovery of structure and function in SCT rats and to explore the mechanisms associated with recovery, 57 adult Sprague-Dawley rats were randomly divided into sham (n = 15), SCT (n = 24), and HSC transplantation groups (n = 15). HSCs (passage 3) labeled by Hoechst 33342, were transplanted intraspinally into the rostral, scar and caudal sites of the transected lesion at 14 days post-operation. Both in vitro and in vivo, HSCs exhibited a capacity for cell proliferation and differentiation. Following HSC transplantation, the animals’ Basso, Beattie, and Bresnahan (BBB). locomotion scale scores increased significantly between weeks 4 and 24 post-SCT, which corresponded to an increased number of 5-hydroxytryptamine (5-HT) fibers and oligodendrocytes. The amount of astrogliosis indicated by immunohistochemical staining, was markedly decreased. Moreover, the decreased expression of neurotrophin- 3 (NT-3) and mitogen-activated protein kinase kinase-1 (MEK-1) after SCT was effectively restored by HSC transplantation. The data from the current study indicate that intraspinally administered HSCs in the chronic phase of SCT results in an improvement in neurological function. Further, the results indicate that intraspinally administered HSCs benefit the underlying mechanisms involved in the enhancement of 5-HT-positive fibers and oligogenesis, the suppression of excessive astrogliosis and the upregulation of NT3-regulated MEK-1 activation in the spinal cord. These crucial findings reveal not only the mechanism of cell therapy, but may also contribute to a novel therapeutic target for the treatment of spinal cord injury (SCI).

Systemic human CD34(+) cells populate the brain and activate host mechanisms to counteract nigrostriatal degeneration

AIM

Here we investigated the neuroprotective potential of systemic CD34(+) human cord blood cells (hCBCs) in a 6-hydroxydopamine rat model of Parkinson's disease.

METHODS

Purified CD34(+) hCBCs were intravenously administered to rats subjected to 6-hydroxydopamine 24 h earlier, and behavioral and immunohistological analysis performed.

RESULTS

CD34(+) hCBC administration significantly prevented host nigrostriatal degeneration inducing behavioral recovery in treated rats. Although donor hCBCs did not differentiate into neural phenotypes, they stimulated the production of new neuroblasts and angiogenesis, and reduced gliosis in recipient animals. Importantly, surviving donor hCBCs were identified, and their tissue distribution pattern correlated with the observed therapeutic effects.

CONCLUSION

Peripherally applied CD34(+) hCBCs can migrate into brain tissues and elicit host-based protective mechanisms to support the survival of midbrain dopamine neurons.

Biodistribution of Infused Human Umbilical Cord Blood Cells in Alzheimer's Disease-Like Murine Model

Human umbilical cord blood cells (HUCBCs), a prolific source of non-embryonic or adult stem cells, have emerged as effective and relatively safe immunomodulators and neuroprotectors, reducing behavioral impairment in animal models of Alzheimer's disease (AD), Parkinson's disease, amyotrophic lateral sclerosis, traumatic brain injury, spinal cord injury, and stroke. In this report, we followed the bioavailability of HUCBCs in AD-like transgenic PSAPP mice and nontransgenic Sprague-Dawley rats. HUCBCs were injected into tail veins of mice or rats at a single dose of 1 × 10(6) or 2.2 × 10(6) cells, respectively, prior to harvesting of tissues at 24 h, 7 days, and 30 days after injection. For determination of HUCBC distribution, tissues from both species were subjected to total DNA isolation and polymerase chain reaction (PCR) amplification of the gene for human glycerol-3-phosphate dehydrogenase. Our results show a relatively similar biodistribution and retention of HUCBCs in both mouse and rat organs. HUCBCs were broadly detected both in the brain and several peripheral organs, including the liver, kidney, and bone marrow, of both species, starting within 7 days and continuing up to 30 days posttransplantation. No HUCBCs were recovered in the peripheral circulation, even at 24 h posttransplantation. Therefore, HUCBCs reach several tissues including the brain following a single intravenous treatment, suggesting that this route can be a viable method of administration of these cells for the treatment of neurodegenerative diseases.

Human mesenchymal stem cells modulate inflammatory cytokines after spinal cord injury in rat

Transplantation of mesenchymal stem cells (MSC) improves functional recovery in experimental models of spinal cord injury (SCI); however, the mechanisms underlying this effect are not completely understood. We investigated the effect of intrathecal implantation of human MSC on functional recovery, astrogliosis and levels of inflammatory cytokines in rats using balloon-induced spinal cord compression lesions. Transplanted cells did not survive at the lesion site of the spinal cord; however, functional recovery was enhanced in the MSC-treated group as was confirmed by the Basso, Beattie, and Bresnahan (BBB) and the flat beam test. Morphometric analysis showed a significantly higher amount of remaining white matter in the cranial part of the lesioned spinal cords. Immunohistochemical analysis of the lesions indicated the rearrangement of the glial scar in MSC-treated animals. Real-time PCR analysis revealed an increased expression of Irf5, Mrc1, Fgf2, Gap43 and Gfap. Transplantation of MSCs into a lesioned spinal cord reduced TNFα, IL-4, IL-1β, IL-2, IL-6 and IL-12 and increased the levels of MIP-1α and RANTES when compared to saline-treated controls. Intrathecal implantation of MSCs reduces the inflammatory reaction and apoptosis, improves functional recovery and modulates glial scar formation after SCI, regardless of cell survival. Therefore, repeated applications may prolong the beneficial effects induced by MSC application.

Human umbilical cord blood-derived mesenchymal stem cell transplantation for the treatment of spinal cord injury

The aim of the present study was to investigate the effects of human umbilical cord blood-derived mesenchymal stem cell (HUCB-MSC) transplantation on the functional restoration of spinal cord injury (SCI). A total of 46 adult Wistar rats were randomly divided into three groups: Injury (n=15), control (n=15) and transplantation (n=16). A SCI model was established using the modified Allen’s method (vulnerating energy, 25 g/cm). The rats in the control and transplantation groups were injected at the site of the injury with physiological saline and HUCB-MSC suspension, respectively. At week one, two and four following treatment, the behavior of the rats was evaluated using the Basso, Beattie, Bresnahan locomotor rating scale. In addition, immunohistochemistry (IHC) was performed on samples from the rats that had been sacrificed four weeks subsequent to the treatment. Recovery of the spinal cord nerve function was identified to be significantly different at week two and four following treatment (P<0.05), and IHC identified that at week four following treatment novel nerve cells were being produced. Thus, transplantation of HUCB-MSCs promoted the recovery of the damaged function of spinal cord nerves in rats with SCI.

Scientific progress regarding neural regeneration in the Web of Science: A 10-year bibliometric analysis

BACKGROUND:

Neural regeneration following nerve injury is an emerging field that attracts extending interests all over the world.

OBJECTIVE:

To use bibliometric indexes to track studies focusing on neural regeneration, and to investigate the relationships among geographic origin, countries and institutes, keywords in the published articles, and especially focus on the region distribution, institution distribution, as well as collaborations in Chinese papers indexed in the Web of Science.

METHODS:

A list of neural regeneration studies was generated by searching the database of the Web of Science-Expanded using the term “Neural Regenera*”. Inclusive criteria: (1) articles in the field of neural regeneration; (2) fundamental research on animals, clinical trials and case reports; (3) article types: article, review, proceedings paper, note, letter, editorial material, discussion, book chapter; (4) year of publication: 2003–2012; and (5) citation database: Science Citation Index-Expanded. Exclusive criteria: (1) articles requiring manual searching or with access only by telephone; (2) unpublished articles; and (3) corrections.

RESULTS:

A total of 4 893 papers were retrieved from the Web of Science published between 2003 and 2012. The papers covered 65 countries or regions, of which the United States ranked first with 1 691 papers. The most relevant papers were in the neurosciences and cell biology, and the keyword “stem cell” was the most frequent. In recent years, China showed a great increase in the number of papers. Over the entire 10 years, there were 922 Chinese papers, with Jilin University ranking first with 58 articles. Chinese papers were published in connection with many countries, including the United States, Japan, and the United Kingdom. Among the connections, the papers published by the Chinese and the American are 107, with the highest rate. With regard to funding, 689 articles were funded from various projects, occupying 74.72% of the total amount. In these projects, National Foundation and Science and Technology programs were the majority.

CONCLUSION:

Our bibliometric analysis provides a historical perspective on the progress of neural regeneration research. At present, the number of articles addressing neural regeneration is increasing rapidly; however, through analysis of citations it is clear that there is a long way to go to improve the academic quality.

Therapeutic potential of mesenchymal stromal cells and MSC conditioned medium in Amyotrophic Lateral Sclerosis (ALS)--in vitro evidence from primary motor neuron cultures, NSC-34 cells, astrocytes and microglia

Administration of mesenchymal stromal cells (MSC) improves functional outcome in the SOD1G93A mouse model of the degenerative motor neuron disorder amyotrophic lateral sclerosis (ALS) as well as in models of other neurological disorders. We have now investigated the effect of the interaction between MSC and motor neurons (derived from both non-transgenic and mutant SOD1G93A transgenic mice), NSC-34 cells and glial cells (astrocytes, microglia) (derived again from both non-transgenic and mutant SOD1G93A ALS transgenic mice) in vitro. In primary motor neurons, NSC-34 cells and astrocytes, MSC conditioned medium (MSC CM) attenuated staurosporine (STS) - induced apoptosis in a concentration-dependent manner. Studying MSC CM-induced expression of neurotrophic factors in astrocytes and NSC-34 cells, we found that glial cell line-derived neurotrophic factor (GDNF) and ciliary neurotrophic factor (CNTF) gene expression in astrocytes were significantly enhanced by MSC CM, with differential responses of non-transgenic and mutant astrocytes. Expression of Vascular Endothelial Growth Factor (VEGF) in NSC-34 cells was significantly upregulated upon MSC CM-treatment. MSC CM significantly reduced the expression of the cytokines TNFα and IL-6 and iNOS both in transgenic and non-transgenic astrocytes. Gene expression of the neuroprotective chemokine Fractalkine (CX3CL1) was also upregulated in mutant SOD1G93A transgenic astrocytes by MSC CM treatment. Correspondingly, MSC CM increased the respective receptor, CX3CR1, in mutant SOD1G93A transgenic microglia. Our data demonstrate that MSC modulate motor neuronal and glial response to apoptosis and inflammation. MSC therefore represent an interesting candidate for further preclinical and clinical evaluation in ALS.

Intravenous administration of human umbilical tissue-derived cells improves neurological function in aged rats after embolic stroke

Intravenous administration of human umbilical tissue-derived cells (hUTC) improves neurological function in young adult rats after stroke. However, stroke is a major cause of death and disability in the aged population, with the majority of stroke patients 65 years and older. The present study investigated the effect of hUTC on aged rats after embolic stroke. Rats at the age of 18-20 months were subjected to embolic middle cerebral artery (MCA) occlusion. Two groups of eight animals each were compared. The investigational group was injected intravenously with 1×10(7) cells/kg in serum-free culture medium (vehicle) 24 h after stroke onset, and the control group was treated with vehicle only at the same time poststroke. Intravenous administration of hUTC significantly improved neurological functional recovery without reducing infarct volume compared to vehicle-treated aged rats. Additionally, hUTC treatment significantly enhanced synaptogenesis and vessel density in the ischemic boundary zone (IBZ). Moreover, hUTC treatment resulted in a trend toward increased progenitor cell proliferation in the subventricular zone (SVZ) compared to vehicle-treated aged rats. Intravenous administration of hUTC improved functional recovery in aged rats after stroke. The enhancement of synaptogenesis and vessel density may contribute to the beneficial effects of hUTC in the treatment of stroke in the aged animal.

Mesenchymal stem cell transplantation reduces glial cyst and improves functional outcome after spinal cord compression

BACKGROUND

Mesenchymal stem cells (MSCs) are multipotent stem cells that have a supportive role in regenerative therapies, especially in the central nervous system, where spontaneous regeneration is limited. MSCs can exert a paracrine activity and modulate the inflammatory response after a central nervous system injury. Spinal cord injury (SCI) leads to permanent neurologic deficits below the injury site, owing to neuronal and axonal damage. Among experimental treatments after SCI, cell transplantation has emerged as a promising approach.

METHODS

Using a compression injury model in the mouse spinal cord, MSCs were acutely transplanted into the lesion cavity; injured mice without the graft served as controls. After 26 days, the survival of MSCs was investigated, and their effect on the formation of glial cyst and on injury-related inflammation was evaluated.

RESULTS

Grafted MSCs remained permanently undifferentiated. The lesion volume was reduced by 31.6% compared with control mice despite the fact that astroglial and microglial activation was not altered by the graft. Sensory and motor tests showed that MSC cell therapy results in improvement on a battery of behavioral tests compared with control mice: MSC-treated mice versus control mice scored 0.00 versus 0.50 in the posture test, 0.00 versus 1.50 in the hindlimb flexion test, 3.00 versus 2.25 in the sensory test, and 7.50 mistakes versus 15.83 mistakes in the foot-fault test.

CONCLUSIONS

These results underscore the therapeutic potential of MSCs, making them promising treatments for central nervous system pathologies.

Effect of In Vitro Exposure of Corticosteroid Drugs, Conventionally Used in AMD Treatment, on Mesenchymal Stem Cells

Age-related macular degeneration (AMD) is a leading cause of legal blindness in individuals over 60 years of age, characterized by the dysfunction of retinal pigmented epithelium cells, specifically in the macular area. Despite several treatment options, AMD therapy remains difficult, especially for exudative AMD. Multipotent mesenchymal stem cells (MSCs), with great plasticity and immunomodulant properties, are a promising cell source for cellular therapy and tissue engineering. We evaluated the effects of steroid drugs, often used to treat AMD, in association with MSCs, in view of a possible application together to treat AMD. Morphology, viability, growth kinetics, and immunophenotype were evaluated on healthy donors' MSCs, treated with triamcinolone acetonide, alcohol-free triamcinolone acetonide, micronized intravitreal triamcinolone and dexamethasone at different concentrations, and in a human retinal pigment epithelial cell line supernatant (ARPE-19). The morphological analysis of MSCs in their standard medium showed a negative correlation with drug concentrations, due to the numerous crystals. Dexamethasone was the least toxic corticosteroid used in this study. ARPE-19 seemed to help cells preserve the typical MSC morphology. In conclusion, this in vitro study demonstrated that high doses of corticosteroid drugs have a negative effect on MSCs, reduced in the presence of a conditioned media.

Multiple intravenous administrations of human umbilical cord blood cells benefit in a mouse model of ALS

BACKGROUND

A promising therapeutic strategy for amyotrophic lateral sclerosis (ALS) is the use of cell-based therapies that can protect motor neurons and thereby retard disease progression. We recently showed that a single large dose (25 × 10⁶ cells) of mononuclear cells from human umbilical cord blood (MNC hUCB) administered intravenously to pre-symptomatic G93A SOD1 mice is optimal in delaying disease progression and increasing lifespan. However, this single high cell dose is impractical for clinical use. The aim of the present pre-clinical translation study was therefore to evaluate the effects of multiple low dose systemic injections of MNC hUCB cell into G93A SOD1 mice at different disease stages.

METHODOLOGY/PRINCIPAL FINDINGS

Mice received weekly intravenous injections of MNC hUCB or media. Symptomatic mice received 10⁶ or 2.5 × 10⁶ cells from 13 weeks of age. A third, pre-symptomatic, group received 10⁶ cells from 9 weeks of age. Control groups were media-injected G93A and mice carrying the normal hSOD1 gene. Motor function tests and various assays determined cell effects. Administered cell distribution, motor neuron counts, and glial cell densities were analyzed in mouse spinal cords. Results showed that mice receiving 10⁶ cells pre-symptomatically or 2.5 × 10⁶ cells symptomatically significantly delayed functional deterioration, increased lifespan and had higher motor neuron counts than media mice. Astrocytes and microglia were significantly reduced in all cell-treated groups.

CONCLUSIONS/SIGNIFICANCE

These results demonstrate that multiple injections of MNC hUCB cells, even beginning at the symptomatic disease stage, could benefit disease outcomes by protecting motor neurons from inflammatory effectors. This multiple cell infusion approach may promote future clinical studies.

Stem cells decreased neuronal cell death after hypoxic stress in primary fetal rat neurons in vitro

To explore stem cell-mediated neuronal protection through extracellular signaling pathways by transplanted stem cells, we sought to identify potential candidate molecules responsible for neuronal protection using an in vitro coculture system. Primary fetal rat hippocampal neurons underwent hypoxia (≤1% oxygen) for 96 h nad then were returned to a normoxic condition. The study group then received rat umbilical cord matrix-derived stem cells, while the control group received fresh media only. The experimental group showed decreased neuronal apoptosis compared to the control group [44.5 ± 1.6% vs. 71.0 ± 4.2% (mean ± SD, p = 0.0005) on day 5] and higher neuronal survival (4.9 ± 1.2 cells/100× field vs. 2.2 ± 0.3, p = 0.02 on day 5). Among 90 proteins evaluated using a protein array, stem cell coculture media showed increased protein secretion of TIMP-1 (5.61-fold), TIMP-2 (4.88), CNTF-Rα (3.42), activin A (2.20), fractalkine (2.04), CCR4 (2.02), and decreased secretion in MIP-2 (0.30-fold), AMPK α1 (0.43), TROY (0.48), and TIMP-3 (0.50). This study demonstrated that coculturing stem cells with primary neurons in vitro decreased neuronal cell death after hypoxia with significantly altered protein secretion. The results suggest that stem cells may offer neuronal protection through extracellular signaling.

Transplantation of umbilical cord blood stem cells for treating spinal cord injury

Spinal cord injury (SCI) develops primary and secondary damage to neural tissue and this often results in permanent disability of the motor and sensory functions. However, there is currently no effective treatment except methylprednisolone, and the use of methylprednisolone has also been questioned due to its moderate efficacy and the drug's downside. Regenerative medicine has remarkably developed since the discovery of stem cells, and many studies have suggested the potential of cell-based therapies for neural injury. Especially, the therapeutic potential of human umbilical cord blood cells (hUCB cells) for intractable neurological disorders has been demonstrated using in vitro and vivo models. The hUCB cells are immune naïve and they are able to differentiate into other phenotypes, including the neural lineage. Their ability to produce several neurotropic factors and to modulate immune and inflammatory reactions has also been noted. Recent evidence has emerged suggesting alternative pathways of graft-mediated neural repair that involve neurotrophic effects. These effects are caused by the release of various growth factors that promote cell survival, angiogenesis and anti-inflammation, and this is all aside from a cell replacement mechanism. In this review, we present the recent findings on the stemness properties and the therapeutic potential of hUCB as a safe, feasible and effective cellular source for transplantation in SCI. These multifaceted protective and restorative effects from hUCB grafts may be interdependent and they act in harmony to promote therapeutic benefits for SCI. Nevertheless, clinical studies with hUCB are still rare because of the concerns about safety and efficiency. Among these concerns, the major histocompatibility in allogeneic transplantation is an important issue to be addressed in future clinical trials for treating SCI.

Protective effects of human umbilical cord blood stem cell intravitreal transplantation against optic nerve injury in rats

BACKGROUND

The majority of studies addressing traumatic optic neuropathy (TON) have focused on drugs, proteins, cytokines, and various surgical techniques. A recent study reported that transplantation of human umbilical cord blood stem cells (hUCBSCs) achieved therapeutic effects on TON, but the exact effects on optic nerve injury are still unknown, and the mechanisms underlying nerve protection remain poorly understood.

METHODS

A total of 135 healthy Sprague-Dawley adult rats were randomly assigned to three groups: sham-surgery, model and transplantation, with 45 rats in each group. TON was induced in the model and transplantation groups via optic nerve crush injury. The crush injury was not performed in the sham-surgery group. Seven days after the injury, 10(6) hUCBSCs were injected into the rat vitreous cavity of transplantation group, and an equal volume of physiological saline was administered to the model and sham-surgery groups. Pathological observation of rat retina tissues was performed by hematoxylin-eosin (H&E) staining at days 3, 7, 14, 21 and 28 post-surgery. The number of retinal ganglion cells (RGCs) and mRNA expression levels of brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) were assessed by the Fluorogold (FG) retrograde labeling and reverse transcriptase-polymerase chain reaction (RT-PCR) methods, respectively.

RESULTS

The number of labeled RGCs and the expression of BDNF and GDNF mRNA obviously increased, and pathological injury was significantly ameliorated in the transplantation group compared to the model group (P < 0.05).

CONCLUSIONS

Via intravitreal transplantation, the hUCBSCs resulted in a significant increase in the survival of the RGCs, and improved pathological changes in the rat retina, following TON. The protective mechanism is correlated with the continuous secretion of BDNF and GDNF in vivo of retina in optic nerve injury rats by the transplanted hUCBSCs.

Human umbilical cord blood-derived mesenchymal stem cells upregulate myelin basic protein in shiverer mice

Human umbilical cord blood is a rich source of pluripotent mesenchymal stem cells and possesses significant advantages over other stem cell sources such as the embryo and bone marrow. In the present study, we aimed to investigate the potential of human umbilical cord blood-derived pluripotent mesenchymal stem cells (hUCB) to myelinate the axons of shiverer mice brains. We also investigated the effect of hUCB treatment on regulation of myelin basic protein in vitro in PC-12 cells, which are normally not myelinated. The results of our study clearly demonstrated that hUCB survive and migrate in vivo and has the potential to myelinate shiverer mice brains. The expression level of myelin basic protein, a major component of the myelin sheath, has been significantly increased in vivo and in vitro as revealed by Western blot, reverse transcription (RT)-polymerase chain reaction, immunohistochemistry, immunocytochemistry, and fluorescent in situ hybridization results. Further, transmission electron microscopic images of hUCB-treated shiverer mice brains showed several layers of myelin around the axons compared with a thin and fragmented layer of myelin in untreated animals. Moreover, the frequency of shivering was diminished 1 month after hUCB treatment in shiverer mice. Our results strongly indicated that hUCB transplantation could be an effective means of treating demyelinating or hypomyelinating disorders.

Menstrual blood cells display stem cell-like phenotypic markers and exert neuroprotection following transplantation in experimental stroke

Cell therapy remains an experimental treatment for neurological disorders. A major obstacle in pursuing the clinical application of this therapy is finding the optimal cell type that will allow benefit to a large patient population with minimal complications. A cell type that is a complete match of the transplant recipient appears as an optimal scenario. Here, we report that menstrual blood may be an important source of autologous stem cells. Immunocytochemical assays of cultured menstrual blood reveal that they express embryonic-like stem cell phenotypic markers (Oct4, SSEA, Nanog), and when grown in appropriate conditioned media, express neuronal phenotypic markers (Nestin, MAP2). In order to test the therapeutic potential of these cells, we used the in vitro stroke model of oxygen glucose deprivation (OGD) and found that OGD-exposed primary rat neurons that were co-cultured with menstrual blood-derived stem cells or exposed to the media collected from cultured menstrual blood exhibited significantly reduced cell death. Trophic factors, such as VEGF, BDNF, and NT-3, were up-regulated in the media of OGD-exposed cultured menstrual blood-derived stem cells. Transplantation of menstrual blood-derived stem cells, either intracerebrally or intravenously and without immunosuppression, after experimentally induced ischemic stroke in adult rats also significantly reduced behavioral and histological impairments compared to vehicle-infused rats. Menstrual blood-derived cells exemplify a source of "individually tailored" donor cells that completely match the transplant recipient, at least in women. The present neurostructural and behavioral benefits afforded by transplanted menstrual blood-derived cells support their use as a stem cell source for cell therapy in stroke.

Future of cord blood for non-oncology uses

For the last 5 years cord blood (CB) has been under intense experimental investigation in in vitro differentiation models and in preclinical animal models ranging from bone to muscle regeneration, cardiovascular diseases including myocardial and peripheral arterial disease, stroke and Parkinson's disease. On the basis of its biological advantages, CB can be an ideal source for tissue regeneration. However, in the hype of the so-called 'plasticity', many cell types have been characterized either on cell surface Ag expression alone or by RNA expression only, and without detailed characterization of genetic pathways; frequently, cells are defined without analysis of cellular function in vitro and in vivo, and the definition of the lineage of origin and cells have not been defined in preclinical studies. Here, we explore not only the most consistent data with regard to differentiation of CB cells in vitro and in vivo, but also show technical limitations, such as why in contrast to cell populations isolated from fresh CB, cryopreserved CB is not the ideal source for tissue regeneration. By taking advantage of numerous CB units discarded due to lack of sufficient hematopoietic cells for clinical transplantation, new concepts to produce off-the-shelf products are presented as well.

Human Umbilical Cord Blood Cell Grafts for Brain Ischemia

Irreversible and permanent damage develop immediately adjacent to the region of reduced cerebral blood perfusion in stroke patients. Currently, the proven thrombolytic treatment for stroke, tissue plasminogen activator, is only effective when administered within 3 h after stroke. These disease characteristics should be taken under consideration in developing any therapeutic intervention designed to widen the narrow therapeutic range, especially cell-based therapy. Over the past several years, our group and others have characterized the therapeutic potential of human umbilical cord blood cells for stroke and other neurological disorders using in vitro and vivo models focusing on the cells' ability to differentiate into nonhematopoietic cells including neural lineage, as well as their ability to produce several neurotrophic factors and modulate immune and inflammatory reaction. Rather than the conventional cell replacement mechanism, we advance alternative pathways of graft-mediated brain repair involving neurotrophic effects resulting from release of various growth factors that afford cell survival, angiogenesis, and anti-inflammation. Eventually, these multiple protective and restorative effects from umbilical cord blood cell grafts may be interdependent and act in harmony in promoting therapeutic benefits for stroke.

Mesenchymal stem cell transplantation in amyotrophic lateral sclerosis: A Phase I clinical trial

Amyotrophic Lateral Sclerosis (ALS) is a devastating incurable disease. Stem-cell-based therapies represent a new possible strategy for ALS clinical research. The objectives of this Phase 1 clinical study were to assess the feasibility and toxicity of mesenchymal stem cell transplantation and to test the impact of a cell therapy in ALS patients. The trial was approved and monitored by the National Institute of Health and by the Ethics Committees of all participating Institutions. Autologous MSCs were isolated from bone marrow, expanded in vitro and analyzed according to GMP conditions. Expanded MSCs were suspended in the autologous cerebrospinal fluid (CSF) and directly transplanted into the spinal cord at a high thoracic level with a surgical procedure. Ten ALS patients were enrolled and regularly monitored before and after transplantation by clinical, psychological, neuroradiological and neurophysiological assessments. There was no immediate or delayed transplant-related toxicity. Clinical, laboratory, and radiographic evaluations of the patients showed no serious transplant-related adverse events. Magnetic resonance images (MRI) showed no structural changes (including tumor formation) in either the brain or the spinal cord. However the lack of post mortem material prevents any definitive conclusion about the vitality of the MSCs after transplantation. In conclusion, this study confirms that MSC transplantation into the spinal cord of ALS patients is safe and that MSCs might have a clinical use for future ALS cell based clinical trials.

Human umbilical cord blood stem cells, myocardial infarction and stroke

Myocardial infarction (MI) and stroke are the first and third leading causes of death in the U.S.A. accounting for more than 1 in 3 deaths per annum. Despite interventional and pharmaceutical advances, the number of people diagnosed with heart disease is on the rise. Therefore, new clinical strategies are needed. Cell-based therapy holds great promise for treatment of these diseases and is currently under extensive preclinical as well as clinical trials. The source and types of stem cells for these clinical applications are questions of great interest. Human umbilical cord blood (hUCB) appears to be a logical candidate as a source of cells. hUCB is readily available, and presents little ethical challenges. Stem cells derived from hUCB are multipotent and immunologically naive. Here is a critical literature review of the beneficial effects of hUCB cell therapy in preclinical trials.

Neural differentiation and potential use of stem cells from the human umbilical cord for central nervous system transplantation therapy

The human umbilical cord is a rich source of autologous stem and progenitor cells. Interestingly, subpopulations of these, particularly mesenchymal-like cells from both cord blood and the cord stroma, exhibited a potential to be differentiated into neuron-like cells in culture. Umbilical cord blood stem cells have demonstrated efficacy in reducing lesion sizes and enhancing behavioral recovery in animal models of ischemic and traumatic central nervous system (CNS) injury. Recent findings also suggest that neurons derived from cord stroma mesenchymal cells could alleviate movement disorders in hemiparkinsonian animal models. We review here the neurogenic potential of umbilical cord stem cells and discuss possibilities of their exploitation as an alternative to human embryonic stem cells or neural stem cells for transplantation therapy of traumatic CNS injury and neurodegenerative diseases.

Traumatic brain injury: future assessment tools and treatment prospects

Traumatic brain injury (TBI) is widespread and leads to death and disability in millions of individuals around the world each year. Overall incidence and prevalence of TBI are likely to increase in absolute terms in the future. Tackling the problem of treating TBI successfully will require improvements in the understanding of normal cerebral anatomy, physiology, and function throughout the lifespan, as well as the pathological and recuperative responses that result from trauma. New treatment approaches and combinations will need to be targeted to the heterogeneous needs of TBI populations. This article explores and evaluates the research evidence in areas that will likely lead to a reduction in TBI-related morbidity and improved outcomes. These include emerging assessment instruments and techniques in areas of structural/chemical and functional neuroimaging and neuropsychology, advances in the realms of cell-based therapies and genetics, promising cognitive rehabilitation techniques including cognitive remediation and the use of electronic technologies including assistive devices and virtual reality, and the emerging field of complementary and alternative medicine.

Recent progress on tissue-resident adult stem cell biology and their therapeutic implications

Recent progress in the field of the stem cell research has given new hopes to treat and even cure diverse degenerative disorders and incurable diseases in human. Particularly, the identification of a rare population of adult stem cells in the most tissues/organs in human has emerged as an attractive source of multipotent stem/progenitor cells for cell replacement-based therapies and tissue engineering in regenerative medicine. The tissue-resident adult stem/progenitor cells offer the possibility to stimulate their in vivo differentiation or to use their ex vivo expanded progenies for cell replacement-based therapies with multiple applications in human. Among the human diseases that could be treated by the stem cell-based therapies, there are hematopoietic and immune disorders, multiple degenerative disorders, such as Parkinson's and Alzheimer's diseases, type 1 or 2 diabetes mellitus as well as eye, liver, lung, skin and cardiovascular disorders and aggressive and metastatic cancers. In addition, the genetically-modified adult stem/progenitor cells could also be used as delivery system for expressing the therapeutic molecules in specific damaged areas of different tissues. Recent advances in cancer stem/progenitor cell research also offer the possibility to targeting these undifferentiated and malignant cells that provide critical functions in cancer initiation and progression and disease relapse for treating the patients diagnosed with the advanced and metastatic cancers which remain incurable in the clinics with the current therapies.

Human umbilical cord blood treatment in a mouse model of ALS: optimization of cell dose

Background

Amyotrophic Lateral Sclerosis (ALS) is a multicausal disease characterized by motor neuron degeneration in the spinal cord and brain. Cell therapy may be a promising new treatment for this devastating disorder. We recently showed that a single low dose (10⁶ cells) of mononuclear human umbilical cord blood (MNC hUCB) cells administered intravenously to G93A mice delayed symptom progression and modestly prolonged lifespan. The aim of this pre-clinical translation study is to optimize the dose of MNC hUCB cells to retard disease progression in G93A mice. Three different doses of MNC hUCB cells, 10×10⁶, 25×10⁶ and 50×10⁶, were administered intravenously into pre-symptomatic G93A mice. Motor function tests and various assays to determine cell effects were performed on these mice.

Methodology/Principal Findings

Our results showed that a cell dose of 25×10⁶ cells significantly increased lifespan of mice by 20–25% and delayed disease progression by 15%. The most beneficial effect on decreasing pro-inflammatory cytokines in the brain and spinal cord was found in this group of mice. Human Th2 cytokines were found in plasma of mice receiving 25×10⁶ cells, although prevalent human Th1 cytokines were indicated in mice with 50×10⁶ cells. High response of splenic cells to mitogen (PHA) was indicated in mice receiving 25×10⁶ (mainly) and 10×10⁶ cells. Significantly increased lymphocytes and decreased neutrophils in the peripheral blood were found only in animals receiving 25×10⁶ cells. Stable reduction in microglia density in both cervical and lumbar spinal cords was also noted in mice administered with 25×10⁶ cells.

Conclusions/Significance

These results demonstrate that treatment for ALS with an appropriate dose of MNC hUCB cells may provide a neuroprotective effect for motor neurons through active involvement of these cells in modulating the host immune inflammatory system response.

Functional recovery in T13–L1 hemisected rats resulting from peripheral nerve rerouting: role of central neuroplasticity

Background: Functional improvements after spinal cord injury (SCI) have been reported anecdotally following neurotization, in other words, rerouting nerves proximal to injured cord segments to distal neuromuscular targets, although the underlying mechanisms remain largely unknown. Aim: To test our hypothesis that neurotization-mediated recovery is primarily attributable to CNS neuroplasticity that therefore manifests optimal response during particular therapeutic windows, we anastomosed the T12 intercostal nerve to the ipsilateral L3 nerve root 1–4 weeks after T13–L1 midline hemisection in rats. Results: While axonal tracing and electromyography revealed limited reinnervation in the target muscles, neurobehavioral function, as assessed by locomotion, extensor postural thrust and sciatic functional index of SCI rats receiving neurotization 7–10 days postinjury (n = 11), recovered to levels close to non-SCI controls with neurotization only (n = 3), beginning 3–5 weeks postanastomosis. Conversely, hindlimb deficits were unchanged in hemisected controls with sham neurotization (n = 7) or 4 weeks-delayed neurotization (n = 3) and in rats that had undergone T13–L1 transection plus bilateral anastomoses (n = 6). Conclusion: Neurotized SCI animals demonstrated multiparameters of neural reorganization in the distal lumbar cord, including enhanced proliferation of endogenous neural stem cells, increased immunoreactivity of serotonin and synaptophysin, and neurite growth/sprouting, suggesting that anastomosing functional nerves with the nerve stump emerging distal to the hemisection stimulates neuroplasticity in the dysfunctional spinal cord. Our conclusion is validated by the fact that severance of the T13–L1 contralateral cord abolished the postanastomosis functional recovery. Neurotization and its neuroplastic sequelae need to be explored further to optimize clinical strategies of post-SCI functional repair.

Current status of experimental cell replacement approaches to spinal cord injury

Despite advances in medical and surgical care, the current clinical therapies for spinal cord injury (SCI) are largely ineffective. During the last 2 decades, the search for new therapies has been revolutionized by the discovery of stem cells, which has inspired scientists and clinicians to search for a stem cell-based reparative approaches to many diseases, including neurotrauma. In the present study, the authors briefly summarize current knowledge related to the pathophysiology of SCI, including the concepts of primary and secondary injury and the importance of posttraumatic demyelination. Key inhibitory obstacles that impede axonal regeneration include the glial scar and a number of myelin inhibitory molecules including Nogo. Recent advancements in cell replacement therapy as a therapeutic strategy for SCI are summarized. The strategies include the use of pluripotent human stem cells, embryonic stem cells, and a number of adult-derived stem and progenitor cells such as mesenchymal stem cells, Schwann cells, olfactory ensheathing cells, and adult-derived neural precursor cells. Although current strategies to repair the subacutely injured cord appear promising, many obstacles continue to render the treatment of chronic injuries challenging. Nonetheless, the future for stem cell-based reparative strategies for treating SCI appears bright.

Umbilical cord blood transfusions for prevention of progressive brain injury and induction of neural recovery: an immunological perspective

One of the most promising treatments for neurodegenerative diseases appears to be human umbilical cord blood cell transplantation. A variety of studies demonstrate some benefit of this method of treatment in a number of different animal models and case studies. However, before the methodologies and results of these animal studies and case studies can be translated into successful widespread treatments, aspects relating to the immunological properties of the transplanted cells must be considered. In this perspective, we discuss the benefit of the cellular immaturity of these cells with respect to the immune response, and compare cord blood transplantation to blood transfusions, as well as discussing what future studies should entail.

Umbilical cord blood stem cell mediated downregulation of fas improves functional recovery of rats after spinal cord injury

Human umbilical cord blood stem cells (hUCB), due to their primitive nature and ability to develop into nonhematopoietic cells of various tissue lineages, represent a potentially useful source for cell-based therapies after spinal cord injury (SCI). To evaluate their therapeutic potential, hUCB were stereotactically transplanted into the injury epicenter, one week after SCI in rats. Our results show the presence of a substantial number of surviving hUCB in the injured spinal cord up to five weeks after transplantation. Three weeks after SCI, apoptotic cells were found especially in the dorsal white matter and gray matter, which are positive for both neuron and oligodendrocyte markers. Expression of Fas on both neurons and oligodendrocytes was efficiently downregulated by hUCB. This ultimately resulted in downregulation of caspase-3 extrinsic pathway proteins involving increased expression of FLIP, XIAP and inhibition of PARP cleavage. In hUCB-treated rats, the PI3K/Akt pathway was also involved in antiapoptotic actions. Further, structural integrity of the cytoskeletal proteins alpha-tubulin, MAP2A&2B and NF-200 has been preserved in hUCB treatments. The behavioral scores of hind limbs of hUCB-treated rats improved significantly than those of the injured group, showing functional recovery. Taken together, our results indicate that hUCB-mediated downregulation of Fas and caspases leads to functional recovery of hind limbs of rats after SCI.

Long-term cultured human umbilical cord neural-like cells transplanted into the striatum of NOD SCID mice

The use of stem cells and other cells as therapies is still in its infancy. One major setback is the limited survival of the grafts, possibly due to immune rejection. Studies were therefore performed with human umbilical cord blood cells (HUCB) to determine the ability of these cells to survive in vivo and the effect of the immune response on their survival by transplantation into the normal striatum of immunodeficient NOD SCID mice. Long-term culture of HUCB cells resulted in several different populations of cells, including one that possessed fine processes and cell bodies that resembled neurons. Their neuronal phenotype was confirmed by immunohistochemical staining for the early neuronal marker TuJ1 and the potentially neural marker Nestin. Five days after cell transplantation of this neuronal phenotype, immunohistochemical staining for human mitochondria confirmed the presence of living HUCB cells in the mouse striatum, with cells localized at the site of injection, expressing early neural and neuronal markers (Nestin and TuJ1) as well as exhibiting neuronal morphology. However, no evidence of surviving cells was apparent 1 month postgrafting. The absence of signs of T cell-mediated rejection, such as CD4 and CD8 lymphocytes and minimal changes in microglia and astrocytes, suggest that cell loss was not due to a T cell-mediated immune response. In conclusion HUCB cells can survive long-term in vitro and undergo neuron-like differentiation. In mice, these cells do not survive a month. This may relate to the differentiated state of the cells transplanted into the unlesioned striatum, rather than T cell-mediated immunological rejection.

Immunomodulation and neuroprotection with mesenchymal bone marrow stem cells (MSCs): a proposed treatment for multiple sclerosis and other neuroimmunological/neurodegenerative diseases

Bone marrow (BM) derived mesenchymal stem cells (MSCs) (non-hematopoietic, stromal cells) can differentiate under certain circumstances into cells from various neuronal and glial type lineages; they also exert immunomodulatory effects. For potential clinical applications, BM-MSCs offer significant practical advantages over other types of stem cells, since they can be obtained from the adult BM (the patient himself being the donor) and can be easily cultured and expanded posing in parallel a very low risk for development of malignancies. We have shown that BM-MSCs cultured with a cocktail of growth factors (containing FGF and BDNF) differentiate into neuronal/glial lineage cells with a predominance of cells expressing astrocytes' markers. BM-MSCs were effective in suppression of chronic EAE in mice and induced neuroprotection, preserving most of the axons in the CNS of successfully-treated animals. Histopathological studies revealed that MSCs could efficiently migrate into the CNS inflamed tissue (both when administered intravenously and intraventricularly) and differentiated into cells expressing neural-glial lineage markers. Our preclinical results indicate that bone marrow can provide a source of stem cells with a potential for migration into inflamed CNS tissue and differentiation into cells expressing neuronal and glial cell markers. Such an approach may provide a feasible and practical way for in situ immunomodulation, neuroprotection and possibly remyelination/regeneration in diseases like multiple sclerosis. We therefore developed a explorative protocol for the evaluation of this therapeutic approach in a small group of patients with MS and other neurodegenerative diseases.

Acetylcholine release from fetal tissue homotopically grafted to the motoneuron-depleted lumbar spinal cord. An in vivo microdialysis study in the awake rat

Grafts of spinal cord (SC) tissue can survive and develop into the severed SC, but no conclusive data are available concerning the functional activity of transplanted neurons. In the present study, suspensions of prelabeled embryonic ventral SC tissue were grafted to the lumbar SC of rats with motoneuron loss induced by perinatal injection of volkensin. Eight to ten months post-grafting, acetylcholine (ACh) release was measured by microdialysis in awake rats, under either basal or stimulated conditions. In normal animals, baseline ACh output averaged 1.6 pmol/30 microl, it exhibited a 4-fold increase after KCl-induced depolarization or handling, and it was completely inhibited by tetrodotoxin administration. Moreover, ACh levels did not change following acute SC transection performed under anesthesia during ongoing dialysis, suggesting an intrinsic source for spinal ACh. Treatment with volkensin produced a severe (>85%) motoneuronal loss accompanied by a similar reduction in baseline ACh release and almost completely abolished effects of depolarization or handling. In transplanted animals, many motoneuron-like labeled cells were found within and just outside the graft area, but apparently in no case were they able to extend fibers towards the denervated muscle. However, the grafts restored baseline ACh output up to near-normal levels and responded with significantly increased release to depolarization, but not to handling. The present findings indicate that spinal neuroblasts can survive and develop within the motoneuron-depleted SC and release ACh in a near-normal, but apparently non-regulated, manner. This may be of importance for future studies involving intraspinal stem cell grafts.