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

Mesenchymal Stem Cells for the Treatment of Spinal Cord Injury in Rat Models: A Systematic Review and Network Meta-Analysis

Transplantation of mesenchymal stem cells (MSCs) is one of the hopeful treatments for spinal cord injury (SCI). Most current studies are in animals, and less in humans, and the optimal transplantation strategy for MSCs is still controversial. In this article, we explore the optimal transplantation strategy of MSCs through a network meta-analysis of the effects of MSCs on SCI in animal models. PubMed, Web of Science, Cochrane Library, Embase, China National Knowledge Infrastructure (CNKI), Wanfang Database, China Science and Technology Journal Database (VIP), and Chinese Biomedical Literature Service System (SinoMed) databases were searched by computer for randomized controlled studies on MSCs for SCI. Two investigators independently completed the literature screening and data extraction based on the inclusion and exclusion criteria. RevMan 5.4 software was used to assess the quality of the included literature. Stata 16.0 software was used for standard meta-analysis and network meta-analysis. Standardized mean difference (SMD) was used for continuous variables to combine the statistics and calculate 95% confidence interval (95% CI). P < 0.05 was considered a statistically significant difference. Cochrane's Q test and the I2 value were used to indicate the magnitude of heterogeneity. A random-effects model was used if I2 > 50% and P < 0.10 indicated significant heterogeneity between studies, and conversely, a fixed-effects model was used. Evidence network diagrams were drawn based on direct comparisons between various interventions. The surface under the cumulative ranking curve area (SUCRA) was used to predict the ranking of the treatment effects of each intervention. A total of 32 animal studies were included in this article for analysis. The results of the standard meta-analysis showed that MSCs improved motor ability after SCI. The network meta-analysis showed that the best treatment effect was achieved for adipose tissue-derived mesenchymal stromal cells (ADMSCs) in terms of cell source and intrathecal (IT) in terms of transplantation modality. For transplantation timing, the best treatment effect was achieved when transplantation was performed in the subacute phase. The available literature suggests that IT transplantation using ADMSCs in the subacute phase may be the best transplantation strategy to improve functional impairment after SCI. Future high-quality studies are still needed to further validate the results of this study to ensure the reliability of the results.

Human Menstrual Blood-Derived Endometrial Stem Cells Promote Functional Recovery by Improving the Inflammatory Microenvironment in a Mouse Spinal Cord Injury Model

Spinal cord injury (SCI) is a traumatic injury of the central nervous system. Because neurons are damaged and difficult to regenerate after SCI, its repair remains challenging. However, recent research on stem cell therapy have favored its use after SCI. In this study, based on the establishment of a mouse SCI model, human menstrual blood-derived endometrial stem cells (MenSCs) were intrathecally injected to explore the role and molecular mechanism of MenSCs in SCI. MenSCs were transplanted following SCI in the animal model, and behavioral evaluations showed that MenSC transplantation improved functional recovery. Therefore, samples were collected after 7 days, and transcriptome sequencing was performed. Gene Ontology (GO) enrichment analysis revealed that SCI is closely related to immune system processes. After transplantation of MenSCs, the immune response was significantly activated. In the Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, MenSC transplantation was found to be closely related to Th1, Th2, and Th17 cell differentiation pathways. Neuronal damage and glial cell proliferation and activation in the different groups were detected by fluorescence immunohistochemistry and Western blotting 7 days after SCI. Simultaneously, the activation of different types of microglia was detected and the expression of pro-inflammatory and anti-inflammatory factors was quantitatively analyzed. The results showed that MenSC transplantation and sonic hedgehog (Shh)-induced MenSCs accelerated neuronal recovery at the injured site, inhibited the formation of glial cells and microglial activation at the injured site, inhibited the expression of inflammatory factors, and improved the inflammatory microenvironment to achieve functional recovery of SCI. This study provides an experimental basis for the study of the role and molecular mechanism of MenSCs in SCI repair, and a reference for the role of Shh-induced MenSCs in SCI repair.

Combined Mesenchymal Stem Cells and Cartilage Acellular Matrix Injection Therapy for Osteoarthritis in Goats

BACKGROUND

Human umbilical cord blood-derived MSCs (hUCB-MSCs) have been studied in osteoarthritis (OA) and cartilage regeneration. Our previous study demonstrated that hUCB-MSCs combined with cartilage acellular matrix injection (CAM Inj.) represent potential therapeutic agents for structural improvement and anti-inflammatory effects in a rabbit model of OA.

METHODS

Based on a previous study, this study has evaluated the safety and efficacy of hUCB-MSCs combined with CAM Inj. in an anterior cruciate ligament transection (ACLT) with medial meniscectomy (MMx) in a goat model. In this study, 27 goats were divided into 5 groups: normal (n = 3), OA (n = 6), OA + CAM Inj. (n = 6), OA + hUCB-MSCs (n = 6), and OA + hUCB-MSCs + CAM Inj. (n = 6). Lameness and radiographic parameters were assessed 6 months after administration, and macroscopic and histological evaluations of the goat articular cartilage were performed 6 months after intervention.

RESULTS

The results showed significant improvement in lameness score only in the OA + hUCB-MSCs group at 5 months after treatment (*p < 0.05), whereas the K&L score showed significant improvement only in the OA + hUCB-MSCs + CAM Inj. group 6 months after intervention (*p < 0.05). In addition, the gross findings showed significance in OA + CAM Inj. and OA + hUCB-MSCs + CAM Inj. groups 6 months after treatment (*p < 0.05 and **p < 0.01).

CONCLUSION

In conclusion, treatment with a combination of hUCB-MSCs and CAM Inj. reduced OA symptoms and induced effective cartilage tissue repair in a goat model. We suggest the combination of hUCB-MSCs and CAM Inj. as an alternative therapy for OA.

Therapeutic Potential of Mesenchymal Stem Cells (MSCs) and MSC-Derived Extracellular Vesicles for the Treatment of Spinal Cord Injury

Spinal cord injury (SCI) is a life-threatening condition that leads to permanent disability with partial or complete loss of motor, sensory, and autonomic functions. SCI is usually caused by initial mechanical insult, followed by a cascade of several neuroinflammation and structural changes. For ameliorating the neuroinflammatory cascades, MSC has been regarded as a therapeutic agent. The animal SCI research has demonstrated that MSC can be a valuable therapeutic agent with several growth factors and cytokines that may induce anti-inflammatory and regenerative effects. However, the therapeutic efficacy of MSCs in animal SCI models is inconsistent, and the optimal method of MSCs remains debatable. Moreover, there are several limitations to developing these therapeutic agents for humans. Therefore, identifying novel agents for regenerative medicine is necessary. Extracellular vesicles are a novel source for regenerative medicine; they possess nucleic acids, functional proteins, and bioactive lipids and perform various functions, including damaged tissue repair, immune response regulation, and reduction of inflammation. MSC-derived exosomes have advantages over MSCs, including small dimensions, low immunogenicity, and no need for additional procedures for culture expansion or delivery. Certain studies have demonstrated that MSC-derived extracellular vesicles (EVs), including exosomes, exhibit outstanding chondroprotective and anti-inflammatory effects. Therefore, we reviewed the principles and patho-mechanisms and summarized the research outcomes of MSCs and MSC-derived EVs for SCI, reported to date.

Stem Cell Therapy for Spinal Cord Injury

Traumatic spinal cord injury (SCI) results in direct and indirect damage to neural tissues, which results in motor and sensory dysfunction, dystonia, and pathological reflex that ultimately lead to paraplegia or tetraplegia. A loss of cells, axon regeneration failure, and time-sensitive pathophysiology make tissue repair difficult. Despite various medical developments, there are currently no effective regenerative treatments. Stem cell therapy is a promising treatment for SCI due to its multiple targets and reactivity benefits. The present review focuses on SCI stem cell therapy, including bone marrow mesenchymal stem cells, umbilical mesenchymal stem cells, adipose-derived mesenchymal stem cells, neural stem cells, neural progenitor cells, embryonic stem cells, induced pluripotent stem cells, and extracellular vesicles. Each cell type targets certain features of SCI pathology and shows therapeutic effects via cell replacement, nutritional support, scaffolds, and immunomodulation mechanisms. However, many preclinical studies and a growing number of clinical trials found that single-cell treatments had only limited benefits for SCI. SCI damage is multifaceted, and there is a growing consensus that a combined treatment is needed.

Schwann Cell-Like Cells: Origin and Usability for Repair and Regeneration of the Peripheral and Central Nervous System

Functional recovery after neurotmesis, a complete transection of the nerve fiber, is often poor and requires a surgical procedure. Especially for longer gaps (>3 mm), end-to-end suturing of the proximal to the distal part is not possible, thus requiring nerve graft implantation. Artificial nerve grafts, i.e., hollow fibers, hydrogels, chitosan, collagen conduits, and decellularized scaffolds hold promise provided that these structures are populated with Schwann cells (SC) that are widely accepted to promote peripheral and spinal cord regeneration. However, these cells must be collected from the healthy peripheral nerves, resulting in significant time delay for treatment and undesired morbidities for the donors. Therefore, there is a clear need to explore the viable source of cells with a regenerative potential similar to SC. For this, we analyzed the literature for the generation of Schwann cell-like cells (SCLC) from stem cells of different origins (i.e., mesenchymal stem cells, pluripotent stem cells, and genetically programmed somatic cells) and compared their biological performance to promote axonal regeneration. Thus, the present review accounts for current developments in the field of SCLC differentiation, their applications in peripheral and central nervous system injury, and provides insights for future strategies.

Enhancement of Neural Stem Cell Proliferation in Rats with Spinal Cord Injury by a Combination of Repetitive Transcranial Magnetic Stimulation (rTMS) and Human Umbilical Cord Blood Mesenchymal Stem Cells (hUCB-MSCs)

BACKGROUND This study was designed to explore the combined effects of repetitive transcranial magnetic stimulation (rTMS) and human umbilical cord blood mesenchymal stem cells (hUCB-MSCs) transplantation on neural stem cell proliferation in rats with spinal cord injury (SCI). MATERIAL AND METHODS SCI was induced in 90 rats by laminectomy at T10. Fifteen rats each were treated with 0.5 Hz rTMS or 10 Hz rTMS or underwent hUCB-MSC transplantation; 15 each were treated with 0.5 Hz rTMS+hUCB-MSCs or 10 Hz rTMS+hUCB-MSCs; and 15 were untreated (control group). The Basso, Beattie, and Bresnahan (BBB) scores and motor evoked potentials (MEPs) were measured, and all rats underwent biotin dextran-amine (BDA) tracing of the corticospinal tract (CST). The levels of expression of neural stem cell proliferation related proteins, including BrdU, nestin, Tuj1, Ng2+ and GFAP, were measured, and the levels of bFGF and EGF determined by Western blotting. RESULTS BBB scores and MEPs were increased after rTMS and hUCB-MSC transplantation, while histologically determined SCI-induced neuron apoptosis was attenuated. The numbers of BDA-positive fibers and Brdu-, nestin- and Tuj1-positive cells were markedly increased and the numbers of Ng2+- and GFAP-positive cells were markedly decreased following treatment with rTMS alone or rTMS plus hUCB-MSC transplantation. The levels of expression of bFGF and EGF were significantly upregulated following rTMS treatment and hUCB-MSC transplantation. Higher performance was observed after combined treatment with rTMS and hUCB-MSC transplantation than after either alone. CONCLUSIONS The combination of rTMS treatment and hUCB-MSC transplantation could attenuate SCI-induced neural stem cell apoptosis and motor dysfunction in rats.

Human umbilical cord derived mesenchymal stem cells in peripheral nerve regeneration

BACKGROUND

Peripheral nerve injury can occur as a result of trauma or disease and carries significant morbidity including sensory and motor loss. The body has limited ability for nerve regeneration and functional recovery. Left untreated, nerve lesions can cause lifelong disability. Traditional treatment options such as neurorrhaphy and neurolysis have high failure rates. Surgical reconstruction with autograft carries donor site morbidity and often provide suboptimal results. Mesenchymal stem cells (MSCs) are known to have promising regenerative potential and have gained attention as a treatment option for nerve lesions. It is however, unclear whether it can be effectively used for nerve regeneration.

AIM

To evaluate the evidence for the use of human umbilical cord derived MSCs (UCMSCs) in peripheral nerve regeneration.

METHODS

We carried out a systematic literature review in accordance with the PRISMA protocol. A literature search was performed from conception to September 2019 using PubMed, EMBASE and Web of Science. The results of eligible studies were appraised. A risk of bias analysis was carried out using Cochrane’s RoB 2.0 tool.

RESULTS

Fourteen studies were included in this review. A total of 279 subjects, including both human and animal were treated with UCMSCs. Four studies obtained UCMSCs from a third-party source and the remainder were harvested by the investigators. Out of the 14 studies, thirteen conducted xenogenic transplantation into nerve injury models. All studies reported significant improvement in nerve regeneration in the UCMSC treated groups compared with the various different controls and untreated groups.

CONCLUSION

The evidence summarised in this PRISMA systematic review of in vivo studies supports the notion that human UCMSC transplantation is an effective treatment option for peripheral nerve injury.

Mesenchymal stem cells transplanted into spinal cord injury adopt immune cell-like characteristics

Background

Mesenchymal stem cells (MSCs) and their cellular response to various stimuli have been characterized in great detail in culture conditions. In contrast, the cellular response of MSCs in an in vivo setting is still uncharted territory. In this study, we investigated the cellular response of MSCs following transplantation into spinal cord injury (SCI).

Methods

Mouse bone marrow-derived MSCs were transplanted 24 h following severe contusion SCI in mice. As controls, MSCs transplanted to the uninjured spinal cord and non-transplanted MSCs were used. At 7 days post transplantation, the MSCs were isolated from the SCI, and their global transcriptional changes, survival, differentiation, proliferation, apoptosis, and phenotypes were investigated using RNA sequencing, immunohistochemistry, and flow cytometry.

Results

MSCs transplanted into SCI downregulated genes related to cell-cycle regulation/progression, DNA metabolic/biosynthetic process, and DNA repair and upregulated genes related to immune system response, cytokine production/response, response to stress/stimuli, signal transduction and signaling pathways, apoptosis, and phagocytosis/endocytosis. MSCs maintained their surface expression of Sca1 and CD29 but upregulated expression of CD45 following transplantation. Transplanted MSCs maintained their surface expression of MHC-I but upregulated surface expression of MHC-II. Transplanted MSCs survived and proliferated to a low extent, did not express Caspase-3, and did not differentiate into neurons or astrocytes.

Conclusion

MSCs transplanted into SCI upregulate expression of CD45 and MHC-II and expression of genes related to cytokine production, phagocytosis/endocytosis, and immune cells/response and thereby adopt immune cell-like characteristics within the recipient.

Electronic supplementary material

The online version of this article (10.1186/s13287-019-1218-9) contains supplementary material, which is available to authorized users.

Extracellular vesicles from human umbilical cord mesenchymal stem cells improve nerve regeneration after sciatic nerve transection in rats

Peripheral nerve injury results in limited nerve regeneration and severe functional impairment. Mesenchymal stem cells (MSCs) are a remarkable tool for peripheral nerve regeneration. The involvement of human umbilical cord MSC-derived extracellular vesicles (hUCMSC-EVs) in peripheral nerve regeneration, however, remains unknown. In this study, we evaluated functional recovery and nerve regeneration in rats that received hUCMSC-EV treatment after nerve transection. We observed that hUCMSC-EV treatment promoted the recovery of motor function and the regeneration of axons; increased the sciatic functional index; resulted in the generation of numerous axons and of several Schwann cells that surrounded individual axons; and attenuated the atrophy of the gastrocnemius muscle. hUCMSC-EVs aggregated to rat nerve defects, down-regulated interleukin (IL)-6 and IL-1β, up-regulated IL-10 and modulated inflammation in the injured nerve. These effects likely contributed to the promotion of nerve regeneration. Our findings indicate that hUCMSC-EVs can improve functional recovery and nerve regeneration by providing a favourable microenvironment for nerve regeneration. Thus, hUCMSC-EVs have considerable potential for application in the treatment of peripheral nerve injury.

Repeated injections of human umbilical cord blood-derived mesenchymal stem cells significantly promotes functional recovery in rabbits with spinal cord injury of two noncontinuous segments

Background

Spinal cord injuries (SCIs) are sustained by an increasing number of patients each year worldwide. The treatment of SCIs has long been a hard nut to crack for doctors around the world. Mesenchymal stem cells (MSCs) have shown benefits for the repair of SCI and recovery of function. Our present study aims to investigate the effects of intravenously infused human umbilical cord blood-derived MSCs (hUCB-MSCs) on functional recovery after subacute spinal cord compression injury of two noncontinuous segments. In addition, we compared the effects of single infusion and repeated intravenous (i.v.) injections on the recovery of spinal cord function.

Methods

A total of 43 adult rabbits were randomly divided into four groups: control, single injection (SI), repeated injection at a 3-day (3RI) or repeated injection at a 7-day interval (7RI) groups. Non-immunosuppressed rabbits in the transplantation groups were infused with either a single complete dose or three divided doses of 2 × 10⁶ hUCB-MSCs (3-day or 7-day intervals) on the first day post decompression. Behavioural scores and somatosensory evoked potentials (SEPs) were used to evaluate hindlimb functional recovery. The survival and differentiation of the transplanted human cells and the activation of the host glial and inflammatory reaction in the injured spinal cord were studied by immunohistochemical staining.

Results

Our results showed that hUCB-MSCs survived, proliferated, and primarily differentiated into oligodendrocytes in the injured area. Treatment with hUCB-MSCs reduced the extent of astrocytic activation, increased axonal preservation, potentially promoted axonal regeneration, decreased the number of Iba-1+ and TUNEL+ cells, increased the amplitude and decreased the onset latency of SEPs and significantly promoted functional improvement. However, these effects were more pronounced in the 3RI group compared with the SI and 7RI groups.

Conclusions

Our results suggest that treatment with i.v. injected hUCB-MSCs after subacute spinal cord compression injury of two noncontinuous segments can promote functional recovery through the differentiation of hUCB-MSCs into specific cell types and the enhancement of anti-inflammatory, anti-astrogliosis, anti-apoptotic and axonal preservation effects. Furthermore, the recovery was more pronounced in the rabbits repeatedly injected with cells at 3-day intervals. The results of this study may provide a novel and useful treatment strategy for the transplantation treatment of SCI.

Electronic supplementary material

The online version of this article (10.1186/s13287-018-0879-0) contains supplementary material, which is available to authorized users.

Overexpression of HIPK2 attenuates spinal cord injury in rats by modulating apoptosis, oxidative stress, and inflammation

HIPK2 is considered to be a tumor suppressor. It also has been implicated in several functions such as apoptosis and inflammation that are linked to spinal cord injury (SCI). However, whether HIPK2 ameliorates the neurological pain of SCI remains unclear. Here, we investigated the effects of HIPK2 on neurological function, oxidative stress, levels of inflammatory cytokines and expression of Bcl-2/Bax in an SCI model. Firstly, we evaluated the therapeutic effects of HIPK2 on neurological pain in the SCI rat using the Basso, Beattie and Bresnahan scores and H & E staining. Overexpression of HIPK2 significantly elevated the levels of brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF), and reduced the mRNA expression of Nogo-A and RhoA in SCI rats. Furthermore, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assays showed that overexpression of HIPK2 significantly reduced the number of apoptotic cells. Overexpression of HIPK2 also decreased expression of Bax and Caspase-3 and elevated expression of Bcl-2 in the SCI model, indicating that HIPK2 exhibited its protective activity by inhibiting SCI-induced apoptosis. Then, we measured the serum concentrations of malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-PX). We also determined the mRNA and protein levels of nuclear factor-κB p65 unit, tumor necrosis factor-α (TNF-α), and interleukin (IL)-1β. HIPK2 overexpression reduced oxidative stress and the levels of inflammatory cytokines compared with SCI control animals. Additionally, acetylation of HIPK2 was reduced in SCI rats. Overexpression of HIPK2 could enhance autophagy by elevating the expression of Beclin-1 and LC3-II while autophagy is regarded as a beneficial regulator to improve spinal cord injury. Together, overexpression of HIPK2 improved contusive SCI induced pain by modulating oxidative stress, Bcl‑2 and Bax signaling, and inflammation, and also regulating autophagy.

Functional collagen conduits combined with human mesenchymal stem cells promote regeneration after sciatic nerve transection in dogs

Numerous studies have focused on the development of novel and innovative approaches for the treatment of peripheral nerve injury using artificial nerve guide conduits. In this study, we attempted to bridge 3.5-cm defects of the sciatic nerve with a longitudinally oriented collagen conduit (LOCC) loaded with human umbilical cord mesenchymal stem cells (hUC-MSCs). The LOCC contains a bundle of longitudinally aligned collagenous fibres enclosed in a hollow collagen tube. Our previous studies showed that an LOCC combined with neurotrophic factors enhances peripheral nerve regeneration. However, it remained unknown whether an LOCC seeded with hUC-MSCs could also promote regeneration. In this study, using various histological and electrophysiological analyses, we found that an LOCC provides mechanical support to newly growing nerves and functions as a structural scaffold for cells, thereby stimulating sciatic nerve regeneration. The LOCC and hUC-MSCs synergistically promoted regeneration and improved the functional recovery in a dog model of sciatic nerve injury. Therefore, the combined use of an LOCC and hUC-MSCs might have therapeutic potential for the treatment of peripheral nerve injury.

The Distribution of Transplanted Umbilical Cord Mesenchymal Stem Cells in Large Blood Vessel of Experimental Design With Traumatic Brain Injury

The authors aim to track the distribution of human umbilical cord mesenchymal stem cells (MSCs) in large blood vessel of traumatic brain injury -rats through immunohistochemical method and small animal imaging system. After green fluorescent protein (GFP) gene was transfected into 293T cell, virus was packaged and MSCs were transfected. Mesenchymal stem cells containing GFP were transplanted into brain ventricle of rats when the infection rate reaches 95%. The immunohistochemical and small animal imaging system was used to detect the distribution of MSCs in large blood vessels of rats. Mesenchymal stem cells could be observed in large vessels with positive GFP expression 10 days after transplantation, while control groups (normal group and traumatic brain injury group) have negative GFP expression. The vascular endothelial growth factor in transplantation group was higher than that in control groups. The in vivo imaging showed obvious distribution of MSCs in the blood vessels of rats, while no MSCs could be seen in control groups. The intravascular migration and homing of MSCs could be seen in rats received MSCs transplantation, and new angiogenesis could be seen in MSCs-transplanted blood vessels.

Phase I-II Clinical Trial Assessing Safety and Efficacy of Umbilical Cord Blood Mononuclear Cell Transplant Therapy of Chronic Complete Spinal Cord Injury

Umbilical cord blood-derived mononuclear cell (UCB-MNC) transplants improve recovery in animal spinal cord injury (SCI) models. We transplanted UCB-MNCs into 28 patients with chronic complete SCI in Hong Kong (HK) and Kunming (KM). Stemcyte Inc. donated UCB-MNCs isolated from human leukocyte antigen (HLA ≥4:6)-matched UCB units. In HK, four patients received four 4-μl injections (1.6 million cells) into dorsal entry zones above and below the injury site, and another four received 8-μl injections (3.2 million cells). The eight patients were an average of 13 years after C5-T10 SCI. Magnetic resonance diffusion tensor imaging of five patients showed white matter gaps at the injury site before treatment. Two patients had fiber bundles growing across the injury site by 12 months, and the rest had narrower white matter gaps. Motor, walking index of SCI (WISCI), and spinal cord independence measure (SCIM) scores did not change. In KM, five groups of four patients received four 4-μl (1.6 million cells), 8-μl (3.2 million cells), 16-μl injections (6.4 million cells), 6.4 million cells plus 30 mg/kg methylprednisolone (MP), or 6.4 million cells plus MP and a 6-week course of oral lithium carbonate (750 mg/day). KM patients averaged 7 years after C3-T11 SCI and received 3-6 months of intensive locomotor training. Before surgery, only two patients walked 10 m with assistance and did not need assistance for bladder or bowel management before surgery. The rest could not walk or do their bladder and bowel management without assistance. At about a year (41-87 weeks), WISCI and SCIM scores improved: 15/20 patients walked 10 m ( p = 0.001) and 12/20 did not need assistance for bladder management ( p = 0.001) or bowel management ( p = 0.002). Five patients converted from complete to incomplete (two sensory, three motor; p = 0.038) SCI. We conclude that UCB-MNC transplants and locomotor training improved WISCI and SCIM scores. We propose further clinical trials.

Blocking of autocrine IGF-1 reduces viability of human umbilical cord mesenchymal stem cells via inhibition of the Akt/Gsk-3β signaling pathway

Human umbilical cord mesenchymal stem cells (hUCMSCs) are able to secrete growth factors, such as hepatocyte growth factor, vascular endothelial growth factor and insulin‑like growth factor‑1 (IGF‑1). The secretion of these growth factors by transplanted hUCMSCs have been identified to stimulate the growth of the host cells in the target organs or tissues. The aim of the present study was to investigate the effect of autocrine IGF‑1 on cell viability of hUCMSCs. The expression levels of IGF‑1 and the IGF‑1 receptor (IGF‑1R) in hUCMSCs were identified using immunocytochemistry staining. In order to block autocrine IGF‑1, hUCMSCs were treated with 5 µg/ml αIR‑3, a specific IGF‑1R antibody, for 24 h. The cells cultured in medium without αIR‑3 were used as the control group. Cell viability, apoptosis, cell cycle and the proliferation‑associated proteins were quantified using an MTT assay, flow cytometry and western blotting. The findings of the present study revealed that IGF‑1 and IGF‑1R were positively expressed in hUCMSCs. Treatment with αIR‑3 significantly reduced cell viability and increased apoptosis of hUCMSCs (P<0.01). Cell cycle analysis indicated that the number of cells in the G2/M phase was reduced in the αIR‑3‑treated group compared with the control group. Western blotting revealed that the expression levels of phosphorylated (p)‑protein kinase B (Akt), p‑glycogen synthase kinase 3β (GSK‑3β), p‑p70 S6 kinase and cyclin D1 were markedly reduced and p21 expression was markedly increased in the αIR‑3‑treated group as compared with the control group (P<0.05). However, no significant difference was identified in the p‑extracellular‑signal regulated kinase 1/2 expression when the αIR‑3 treatment group was compared with the control group. (P>0.05). The findings of the present study suggested that the autocrine IGF‑1 from hUCMSCs may be capable of influencing cell viability of hUCMSCs, which may be associated with activation of Akt/GSK‑3β signaling pathway.

Induction of mice adult bone marrow mesenchymal stem cells into functional motor neuron-like cells

The differentiation of mesenchymal stem cells (MSC) into acetylcholine secreted motor neuron-like cells, followed by elongation of the cell axon, is a promising treatment for spinal cord injury and motor neuron cell dysfunction in mammals. Differentiation is induced through a pre-induction step using Beta- mercaptoethanol (BME) followed by four days of induction with retinoic acid and sonic hedgehog. This process results in a very efficient differentiation of BM-MSCs into motor neuron-like cells. Immunocytochemistry showed that these treated cells had specific motor neural markers: microtubule associated protein-2 and acetylcholine transferase. The ability of these cells to function as motor neuron cells was assessed by measuring acetylcholine levels in a culture media during differentiation. High-performance liquid chromatography (HPLC) showed that the differentiated cells were functional. Motor neuron axon elongation was then induced by adding different concentrations of a nerve growth factor (NGF) to the differentiation media. Using a collagen matrix to mimic the natural condition of neural cells in a three-dimensional model showed that the MSCs were successfully differentiated into motor neuron-like cells. This process can efficiently differentiate MSCs into functional motor neurons that can be used for autologous nervous system therapy and especially for treating spinal cord injuries.

Human umbilical cord blood derived mesenchymal stem cells improve cardiac function in cTnT(R141W) transgenic mouse of dilated cardiomyopathy

Cell transplantation is a promising strategy in regenerative medicine. Beneficial effects of bone marrow mesenchymal stem cells (BM-MSCs) on heart disease have been widely reported. However, the MSCs in these studies have been mainly derived from autologous animals, and data on MSCs from human umbilical cord blood (UCB-MSCs) are still scarce. We investigated whether intramyocardial xenogeneic administration of UCB-MSCs is beneficial for preserving heart function in a cTnT(R141W) transgenic mouse of dilated cardiomyopathy (DCM). Cultured UCB-MSCs, which were identified by there morphology, differentiation and cell surface markers, were transplanted into cTnT(R141W) transgenic mice to examine apoptosis, fibrosis, vasculogenesis and the associated Akt pathway. Moreover, we measured the expression levels of VEGF and IGF-1, which are growth factors required for differentiation into cardiomyocytes, and are also involved in cardiac regeneration and improving heart function. One month after transplantation, MSCs significantly decreased chamber dilation and contractile dysfunction in the cTnT(R141W) mice. MSCs transplanted hearts showed a significant decrease in cardiac apoptosis and its regulation by the Akt pathway. Cardiac fibrosis and cytoplasmic vacuolisation were significantly attenuated in the MSCs group. Importantly, the levels of VEGF and IGF-1 were increased in the MSCs transplanted hearts. In vitro, the MSC-conditioned medium displayed anti-apoptotic activity in h9c2 cardiomyocytes subjected to hypoxia. These results further confirm the paracrine effects of MSCs. In conclusion, UCB-MSCs preserve cardiac function after intramyocardial transplantation in a DCM mouse, and this effect may be associated with reductions in cellular apoptosis, inflammation, hypertrophy and myocardial fibrosis; in addition to; up-regulation of Akt, VEGF and IGF-1; and enhanced angiogenesis.

Intraocular pressure reduction and neuroprotection conferred by bone marrow-derived mesenchymal stem cells in an animal model of glaucoma

INTRODUCTION

Glaucoma is a sight-threatening retinal neuropathy associated with elevated intraocular pressure (IOP) due to degeneration and fibrosis of the trabecular meshwork (TM). Glaucoma medications aim to reduce IOP without targeting the specific TM pathology, Bone-marrow mesenchymal stem cells (MSCs) are used today in various clinical studies. Here, we investigated the potential of MSCs therapy in an glaucoma-like ocular hypertension (OHT) model and decipher in vitro the effects of MSCs on primary human trabecular meshwork cells.

METHODS

Ocular hypertension model was performed by cauterization of 3 episcleral veins (EVC) of Long-Evans male rat eyes. MSCs were isolated from rat bone marrow, amplified in vitro and tagged with quantum dot nanocrystals. Animals were distributed as 1) MSCs group receiving 5.10(5)cells/6μl Minimum Essential Medium and 2) MEM group receiving 6μl MEM (n = 10 each). Injections were performed into the anterior chamber of 20 days-hypertensive eyes and IOP was monitored twice a week for 4 weeks. At the end of experiment, cell distribution in the anterior segment was examined in confocal microscopy on flat mounted corneas. Moreover, we tested in vitro effects of MSCs conditioned medium (MSC-CM) on primary human trabecular meshwork cells (hTM cells) using Akt activation, myosin phosphorylation and TGF-β2-dependent profibrotic phenotype in hTM cells.

RESULTS

We demonstrated a rapid and long-lasting in vivo effect of MSCs transplantation that significantly reduced IOP in hypertensive eyes induced by EVC. MSCs were located to the ciliary processes and the TM. Enumeration of RGCs on whole flat-mounted retina highlighted a protective effect of MSCs on RGCs death. In vitro, MSC-CM promotes: (i) hTM cells survival by activating the antiapoptotic pathway, Akt, (ii) hTM cells relaxation as analyzed by the decrease in myosin phosphorylation and (iii) inhibition of TGF-β2-dependent profibrotic phenotype acquisition in hTM cells.

CONCLUSIONS

MSCs injection in the ocular anterior chamber in a rat model of OHT provides neuroprotective effect in the glaucoma pathophysiology via TM protection. These results demonstrate that MSCs constitute promising tool for treating ocular hypertension and retinal cell degeneration.

Human umbilical cord mesenchymal stem cells promote peripheral nerve repair via paracrine mechanisms

Human umbilical cord-derived mesenchymal stem cells (hUCMSCs) represent a promising young-state stem cell source for cell-based therapy. hUCMSC transplantation into the transected sciatic nerve promotes axonal regeneration and functional recovery. To further clarify the paracrine effects of hUCMSCs on nerve regeneration, we performed human cytokine antibody array analysis, which revealed that hUCMSCs express 14 important neurotrophic factors. Enzyme-linked immunosorbent assay and immunohistochemistry showed that brain-derived neurotrophic factor, glial-derived neurotrophic factor, hepatocyte growth factor, neurotrophin-3, basic fibroblast growth factor, type I collagen, fibronectin and laminin were highly expressed. Treatment with hUCMSC-conditioned medium enhanced Schwann cell viability and proliferation, increased nerve growth factor and brain-derived neurotrophic factor expression in Schwann cells, and enhanced neurite growth from dorsal root ganglion explants. These findings suggest that paracrine action may be a key mechanism underlying the effects of hUCMSCs in peripheral nerve repair.

Biodegradable chitin conduit tubulation combined with bone marrow mesenchymal stem cell transplantation for treatment of spinal cord injury by reducing glial scar and cavity formation

We examined the restorative effect of modified biodegradable chitin conduits in combination with bone marrow mesenchymal stem cell transplantation after right spinal cord hemisection injury. Immunohistochemical staining revealed that biological conduit sleeve bridging reduced glial scar formation and spinal muscular atrophy after spinal cord hemisection. Bone marrow mesenchymal stem cells survived and proliferated after transplantation in vivo, and differentiated into cells double-positive for S100 (Schwann cell marker) and glial fibrillary acidic protein (glial cell marker) at 8 weeks. Retrograde tracing showed that more nerve fibers had grown through the injured spinal cord at 14 weeks after combination therapy than either treatment alone. Our findings indicate that a biological conduit combined with bone marrow mesenchymal stem cell transplantation effectively prevented scar formation and provided a favorable local microenvironment for the proliferation, migration and differentiation of bone marrow mesenchymal stem cells in the spinal cord, thus promoting restoration following spinal cord hemisection injury.