Effects of Bone-Marrow-Derived MSC Transplantation on Functional Recovery in a Rat Model of Spinal Cord Injury: Comparisons of Transplant Locations and Cell Concentrations

Treatment of Syringomyelia Characterized by Focal Dilatation of the Central Canal Using Mesenchymal Stem Cells and Neural Stem Cells

BACKGROUND

Syringomyelia is a progressive chronic disease that leads to nerve pain, sensory dissociation, and dyskinesia. Symptoms often do not improve after surgery. Stem cells have been widely explored for the treatment of nervous system diseases due to their immunoregulatory and neural replacement abilities.

METHODS

In this study, we used a rat model of syringomyelia characterized by focal dilatation of the central canal to explore an effective transplantation scheme and evaluate the effect of mesenchymal stem cells and induced neural stem cells for the treatment of syringomyelia.

RESULTS

The results showed that cell transplantation could not only promote syrinx shrinkage but also stimulate the proliferation of ependymal cells, and the effect of this result was related to the transplantation location. These reactions appeared only when the cells were transplanted into the cavity. Additionally, we discovered that cell transplantation transformed activated microglia into the M2 phenotype. IGF1-expressing M2 microglia may play a significant role in the repair of nerve pain.

CONCLUSION

Cell transplantation can promote cavity shrinkage and regulate the local inflammatory environment. Moreover, the proliferation of ependymal cells may indicate the activation of endogenous stem cells, which is important for the regeneration and repair of spinal cord injury.

Conditioned medium-enriched umbilical cord mesenchymal stem cells: a potential therapeutic strategy for spinal cord injury, unveiling transcriptomic and secretomic insights

INTRODUCTION

Spinal cord injury (SCI) leads to significant destruction of nerve tissue, causing the degeneration of axons and the formation of cystic cavities. This study aimed to examine the characteristics of human umbilical cord-derived mesenchymal stem cells (HUCMSCs) cultured in a serum-free conditioned medium (CM) and assess their effectiveness in a well-established hemitransection SCI model.

MATERIALS AND METHODS

In this study, HUCMSCs cultured medium was collected and characterized by measuring IL-10 and identifying proteomics using mass spectroscopy. This collected serum-free CM was further used in the experiments to culture and characterize the HUMSCs. Later, neuronal cells derived from CM-enriched HUCMSC were tested sequentially using an injectable caffeic acid-bioconjugated gelatin (CBG), which was further transplanted in a hemitransection SCI model. In vitro, characterization of CM-enriched HUCMSCs and differentiated neuronal cells was performed using flow cytometry, immunofluorescence, electron microscopy, and post-transplant analysis using immunohistology analysis, qPCR, in vivo bioluminescence imaging, and behavioral analysis using an infrared actimeter.

RESULTS

The cells that were cultured in the conditioned media produced a pro-inflammatory cytokine called IL-10. Upon examining the secretome of the conditioned media, the Kruppel-like family of KRAB and zinc-finger proteins (C2H2 and C4) were found to be activated. Transcriptome analysis also revealed an increased expression of ELK-1, HOXD8, OTX2, YY1, STAT1, ETV7, and PATZ1 in the conditioned media. Furthermore, the expression of Human Stem-101 confirmed proliferation during the first 3 weeks after transplantation, along with the migration of CBG-UCNSC cells within the transplanted area. The gene analysis showed increased expression of Nestin, NeuN, Calb-2, Msi1, and Msi2. The group that received CBG-UCNSC therapy showed a smooth recovery by the end of week 2, with most rats regaining their walking abilities similar to those before the spinal cord injury by week 5.

CONCLUSIONS

In conclusion, the CBG-UCNSC method effectively preserved the integrity of the transplanted neuronal-like cells and improved locomotor function. Thus, CM-enriched cells can potentially reduce biosafety risks associated with animal content, making them a promising option for clinical applications in treating spinal cord injuries.

BM-MSC-Loaded Graphene-Collagen Cryogels Ameliorate Neuroinflammation in a Rat Spinal Cord Injury Model

A major obstacle to axonal regeneration following spinal cord injury (SCI) is neuroinflammation mediated by astrocytes and microglial cells. We previously demonstrated that graphene-based collagen hydrogels alone can decrease neuroinflammation in SCI. Their regenerative potential, however, is poorly understood and incomplete. Furthermore, stem cells have demonstrated both neuroprotective and regenerative properties in spinal cord regeneration, although there are constraints connected with the application of stem cell-based therapy. In this study, we have analyzed the regeneration capability of human bone marrow mesenchymal stem cell (BM-MSC)-loaded graphene-cross-linked collagen cryogels (Gr-Col) in a thoracic (T10-T11) hemisection model of SCI. Our study found that BM-MSC-loaded Gr-Col improves axonal regeneration, reduces neuroinflammation by decreasing astrocyte reactivity, and promotes M2 macrophage polarization. BM-MSC-loaded-Gr-Col demonstrated enhanced regenerative potential compared to Gr-Col and the injury group control. Next-generation sequencing (NGS) analysis revealed that BM-MSC-loaded-Gr-Col modulates the JAK2-STAT3 pathway, thus decreasing the reactive and scar-forming astrocyte phenotype. The decrease in neuroinflammation in the BM-MSC-loaded-Gr-Col group is attributed to the modulation of Notch/Rock and STAT5a/b and STAT6 signaling. Overall, Gene Set Enrichment Analysis suggests the promising role of BM-MSC-loaded-Gr-Col in promoting axonal regeneration after SCI by modulating molecular pathways such as the PI3/Akt pathway, focal adhesion kinase, and various inflammatory pathways.

The Promising Role of a Zebrafish Model Employed in Neural Regeneration Following a Spinal Cord Injury

Spinal cord injury (SCI) is a devastating event that results in a wide range of physical impairments and disabilities. Despite the advances in our understanding of the biological response to injured tissue, no effective treatments are available for SCIs at present. Some studies have addressed this issue by exploring the potential of cell transplantation therapy. However, because of the abnormal microenvironment in injured tissue, the survival rate of transplanted cells is often low, thus limiting the efficacy of such treatments. Many studies have attempted to overcome these obstacles using a variety of cell types and animal models. Recent studies have shown the utility of zebrafish as a model of neural regeneration following SCIs, including the proliferation and migration of various cell types and the involvement of various progenitor cells. In this review, we discuss some of the current challenges in SCI research, including the accurate identification of cell types involved in neural regeneration, the adverse microenvironment created by SCIs, attenuated immune responses that inhibit nerve regeneration, and glial scar formation that prevents axonal regeneration. More in-depth studies are needed to fully understand the neural regeneration mechanisms, proteins, and signaling pathways involved in the complex interactions between the SCI microenvironment and transplanted cells in non-mammals, particularly in the zebrafish model, which could, in turn, lead to new therapeutic approaches to treat SCIs in humans and other mammals.

Adipose-Derived Mesenchymal Stromal Cell Transplantation for Severe Spinal Cord Injury: Functional Improvement Supported by Angiogenesis and Neuroprotection

Mesenchymal stromal cell transplantation alone is insufficient when motor dysfunction is severe; combination therapy with rehabilitation could improve motor function. Here, we aimed to analyze the characteristics of adipose-derived MSCs (AD-MSCs) and determine their effectiveness in severe spinal cord injury (SCI) treatment. A severe SCI model was created and motor function were compared. The rats were divided into AD-MSC-transplanted treadmill exercise-combined (AD-Ex), AD-MSC-transplanted non-exercise (AD-noEx), PBS-injected exercise (PBS-Ex), and no PBS-injected exercise (PBS-noEx) groups. In cultured cell experiments, AD-MSCs were subjected to oxidative stress, and the effects on the extracellular secretion of AD-MSCs were investigated using multiplex flow cytometry. We assessed angiogenesis and macrophage accumulation in the acute phase. Spinal cavity or scar size and axonal preservation were assessed histologically in the subacute phase. Significant motor function improvement was observed in the AD-Ex group. Vascular endothelial growth factor and C-C motif chemokine 2 expression in AD-MSC culture supernatants increased under oxidative stress. Enhanced angiogenesis and decreased macrophage accumulation were observed at 2 weeks post-transplantation, whereas spinal cord cavity or scar size and axonal preservation were observed at 4 weeks. Overall, AD-MSC transplantation combined with treadmill exercise training improved motor function in severe SCI. AD-MSC transplantation promoted angiogenesis and neuroprotection.

Recombinant Adenoviruses for Delivery of Therapeutics Following Spinal Cord Injury

The regeneration of nerve tissue after spinal cord injury is a complex and poorly understood process. Medication and surgery are not very effective treatments for patients with spinal cord injuries. Gene therapy is a popular approach for the treatment of such patients. The delivery of therapeutic genes is carried out in a variety of ways, such as direct injection of therapeutic vectors at the site of injury, retrograde delivery of vectors, and ex vivo therapy using various cells. Recombinant adenoviruses are often used as vectors for gene transfer. This review discusses the advantages, limitations and prospects of adenovectors in spinal cord injury therapy.

Cotransplantation with RADA16-PRG-Self-Assembled Nanopeptide Scaffolds, Bone Mesenchymal Stem Cells and Brain-Derived Neurotrophic Factor-Adeno-Associated Virus Promote Functional Repair After Acute Spinal Cord Injury in Rats

We transplanted RADA16-PRG self-assembled nanopeptide scaffolds (SAPNSs), bone mesenchymal stem cells (BMSCs), and a brain-derived neurotrophic factor (BDNF)-expressing adeno-associated virus (AAV) into rats subjected to acute spinal cord injury (SCI) to investigate the effects of these transplantations on acute SCI repair and explore their mechanisms. Forty-eight SCI rats were randomly divided into four groups: BBR, BR, B, and NC groups. Seven and 28 days after SCI, evoked potentials (EPs) and BBB scores were assessed to evaluate the recovery of rats' motor behavior and sensory function after injury. HE and toluidine blue staining were performed to investigate the histological structure of the spinal cord tissue of rats from each group, and immunofluorescence staining was used to observe the red fluorescent protein (RFP) intensity of BMSCs and glial fibrillary acidic protein (GFAP) and neurofilament (NF) in the damaged area in each group. RT-PCR was utilized to detect the expression levels of the BDNF, GFAP, and neuron-specific enolase (NSE) genes in the injured area in each group. The results showed that cotransplantation of RADA16-PRG-SAPNs, BMSCs, and BDNF-AVV promoted the spinal cord's motor and sensory function of SCI rats; increased levels of BMSCs, inhabited glial cells proliferation, and promoted neurons proliferations in the injured area; and increased NF, BDNF, and NSE levels and decreased its GFAP in the injured area. Thus, cotransplantation of RADA16-PRG-SAPNS, BMSCs, and BDNF-AAV can prolong the survival time of BMSCs in rats, reduce the postoperative scarring caused by glial proliferation, and promote the migration and proliferation of neurons in the injured area, resulting in the promotion of functional repair after acute SCI.

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.

Modeling chronic cervical spinal cord injury in aged rats for cell therapy studies

With an expanding elderly population, an increasing number of older adults will experience spinal cord injury (SCI) and might be candidates for cell-based therapies, yet there is a paucity of research in this age group. The objective of the present study was to analyze how aged rats tolerate behavioral testing, surgical procedures, post-operative complications, intra-spinal cell transplantation and immunosuppression, and to examine the effectiveness of human iPSC-derived Neural Progenitor Cells (IMR90-hiPSC-NPCs) in a model of SCI. We performed behavioral tests in rats before and after inducing cervical hemi-contusions at C4 level with a fourth-generation Ohio State University Injury Device. Four weeks later, we injected IMR90-hiPSC-NPCs in animals that were immunosuppressed by daily cyclosporine injection. Four weeks after injection we analyzed locomotor behavior and mortality, and histologically assessed the survival of transplanted human NPCs. As rats aged, their success at completing behavioral tests decreased. In addition, we observed high mortality rates during behavioral training (41.2%), after cervical injury (63.2%) and after cell injection (50%). Histological analysis revealed that injected cells survived and remained at and around the grafted site and did not cause tumors. No locomotor improvement was observed in animals four weeks after IMR90-hiPSC-NPC transplantation. Our results show that elderly rats are highly vulnerable to interventions, and thus large groups of animals must be initially established to study the potential efficacy of cell-based therapies in age-related chronic myelopathies.

Optimizing Olfactory Ensheathing Cell Transplantation for Spinal Cord Injury Repair

Cell transplantation constitutes an important avenue for development of new treatments for spinal cord injury (SCI). These therapies are aimed at supporting neural repair and/or replacing lost cells at the injury site. To date, various cell types have been trialed, with most studies focusing on different types of stem cells or glial cells. Here, we review commonly used cell transplantation approaches for spinal cord injury (SCI) repair, with focus on transplantation of olfactory ensheathing cells (OECs), the glial cells of the primary olfactory nervous system. OECs are promising candidates for promotion of neural repair given that they support continuous regeneration of the olfactory nerve that occurs throughout life. Further, OECs can be accessed from the nasal mucosa (olfactory neuroepithelium) at the roof of the nasal cavity and can be autologously transplanted. OEC transplantation has been trialed in many animal models of SCI, as well as in human clinical trials. While several studies have been promising, outcomes are variable and the method needs improvement to enhance aspects such as cell survival, integration, and migration. As a case study, we include the approaches used by our team (the Clem Jones Centre for Neurobiology and Stem Cell Research, Griffith University, Nathan, QLD, Australia) to address the current problems with OEC transplantation and discuss how the therapeutic potential of OEC transplantation can be improved. Our approach includes discovery research to improve our knowledge of OEC biology, identifying natural and synthetic compounds to stimulate the neural repair properties of OECs, and designing three-dimensional cell constructs to create stable and transplantable cell structures.

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.

Human Mesenchymal Stem Cells for Spinal Cord Injury

Spinal Cord Injury (SCI), as a devastating and life-altering neurological disorder, is one of the most serious health issues. Currently, the management of acute SCI includes pharmacotherapy and surgical decompression. Both the approaches have been observed to have adverse physiological effects on SCI patients. Therefore, novel therapeutic targets for the management of SCI are urgently required for developing cell-based therapies. Multipotent stem cells, as a novel strategy for the treatment of tissue injury, may provide an effective therapeutic option against many neurological disorders. Mesenchymal stem cells (MSCs) or multipotent stromal cells can typically self-renew and generate various cell types. These cells are often isolated from bone marrow (BM-MSCs), adipose tissues (AD-MSCs), umbilical cord blood (UCB-MSCs), and placenta (PMSCs). MSCs have remarkable potential for the development of regenerative therapies in animal models and humans with SCI. Herein, we summarize the therapeutic potential of human MSCs in the treatment of SCI.

Effects of Edaravone on Functional Recovery of a Rat Model with Spinal Cord Injury Through Induced Differentiation of Bone Marrow Mesenchymal Stem Cells into Neuron-Like Cells

Edaravone can induce differentiation of bone marrow mesenchymal stem cells (BMSCs) into neuron-like cells and replace lost cells by transplanting neuron-like cells to repair spinal cord injury (SCI). In this study, BMSCs were derived from the bone marrow of male Wistar rats (4 weeks old) through density gradient centrifugation (1.073 g/mL), and the cell purity of BMSCs was up to 95%. The combined injection of basic fibroblast growth factor and edaravone was conducted to differentiate BMSCs into neuron-like cells. In this study, 120 male Wistar rats were used to establish the model of semitransverse SCI; on the seventh day, neuron-like cells were labeled by BrdU and then injected into the epicenter of the injury of rats. On the 14th day after cell transplantation, the biotin dextran amine (BDA) fluorescent agent was used to track the repair of nerve damage. At 7, 14, 21, and 30 days after SCI, the Basso, Beattie, and Bresnahan (BBB) locomotor scale method was used to measure the functional recovery of hind limbs in rats. Additionally, hematoxylin and eosin (H&E) staining, Nissl staining, immunohistochemistry, transmission electron microscopy (TEM), Western blotting, and Real-time quantitative reverse transcripion PCR (qRT-PCR) were used to observe the regeneration of nerve cells. In the edaravone+BMSC group, behavioral analysis of locomotor function showed that functional recovery was significantly enhanced after transplantation of the cells, BrdU-positive cells could be observed scattered in the injured area and extended to both the head and tail, and the BDA tracer shows that the edaravone+BMSC group emits more fluorescent signals. Additionally, H&E staining, Nissl staining, and immunohistochemistry revealed that the space of spinal cord tissue was attenuated and the neurons were increased. Western blotting and qRT-PCR showed that the expression levels of neuron-specific enolase (NSE), Nestin, and neurofilament 200 (NF) were increased, while the expression of glial fibrillary acidic protein (GFAP) was decreased. TEM showed that cytoplasmic edema was reduced, mitochondrial vacuoles were attenuated, and nuclear chromatin concentration was declined after transplantation of neuron-like cells. Moreover, with the extension of time of edaravone+BMSC transplantation, the structures of mitochondria and endoplasmic reticulum tended to be normal. In summary, the induced differentiation of BMSC transplantation can significantly promote the functional repair of SCI.

Progress in Stem Cell Therapy for Spinal Cord Injury

Background

Spinal cord injury (SCI) is one of the serious neurological diseases that occur in young people with high morbidity and disability. However, there is still a lack of effective treatments for it. Stem cell (SC) treatment of SCI has gradually become a new research hotspot over the past decades. This article is aimed at reviewing the research progress of SC therapy for SCI.

Methods

Review the literature and summarize the effects, strategies, related mechanisms, safety, and clinical application of different SC types and new approaches in combination with SC in SCI treatment.

Results

A large number of studies have focused on SC therapy for SCI, most of which showed good effects. The common SC types for SCI treatment include mesenchymal stem cells (MSCs), hematopoietic stem cells (HSCs), neural stem cells (NSCs), induced pluripotent stem cells (iPSCs), and embryonic stem cells (ESCs). The modes of treatment include in vivo and in vitro induction. The pathways of transplantation consist of intravenous, transarterial, nasal, intraperitoneal, intrathecal, and intramedullary injections. Most of the SC treatments for SCI use a number of cells ranging from tens of thousands to millions. Early or late SC administration, application of immunosuppressant or not are still controversies. Potential mechanisms of SC therapy include tissue repair and replacement, neurotrophy, and regeneration and promotion of angiogenesis, antiapoptosis, and anti-inflammatory. Common safety issues include thrombosis and embolism, tumorigenicity and instability, infection, high fever, and even death. Recently, some new approaches, such as the pharmacological activation of endogenous SCs, biomaterials, 3D print, and optogenetics, have been also developed, which greatly improved the application of SC therapy for SCI.

Conclusion

Most studies support the effects of SC therapy on SCI, while a few studies do not. The cell types, mechanisms, and strategies of SC therapy for SCI are very different among studies. In addition, the safety cannot be ignored, and more clinical trials are required. The application of new technology will promote SC therapy of SCI.

A combination of mesenchymal stem cells and scaffolds promotes motor functional recovery in spinal cord injury: a systematic review and meta-analysis

OBJECTIVE

There is controversy about the role of scaffolds as an adjunctive therapy to mesenchymal stem cell (MSC) transplantation in spinal cord injury (SCI). Thus, the authors aimed to design a meta-analysis on preclinical evidence to evaluate the effectiveness of combination therapy of scaffold + MSC transplantation in comparison with scaffolds alone and MSCs alone in improving motor dysfunction in SCI.

METHODS

Electronic databases including Medline, Embase, Scopus, and Web of Science were searched from inception until the end of August 2018. Two independent reviewers screened related experimental studies. Animal studies that evaluated the effectiveness of scaffolds and/or MSCs on motor function recovery following experimental SCI were included. The findings were reported as standardized mean difference (SMD) and 95% confidence interval (CI).

RESULTS

A total of 34 articles were included in the meta-analysis. Analyses show that combination therapy in comparison with the scaffold group alone (SMD 2.00, 95% CI 1.53-2.46, p < 0.0001), the MSCs alone (SMD 1.58, 95% CI 0.84-2.31, p < 0.0001), and the nontreated group (SMD 3.52, 95% CI 2.84-4.20, p < 0.0001) significantly improved motor function recovery. Co-administration of MSCs + scaffolds only in the acute phase of injury (during the first 3 days after injury) leads to a significant recovery compared to scaffold alone (SMD 2.18, p < 0.0001). In addition, the cotransplantation of scaffolds with bone marrow-derived MSCs (SMD 1.99, p < 0.0001) and umbilical cord-derived MSCs (SMD 1.50, p = 0.001) also improved motor function following SCI.

CONCLUSIONS

The findings showed that scaffolds + MSCs is more effective than scaffolds and MSCs alone in improving motor function following SCI in animal models, when used in the acute phase of injury.

Human adipose tissue- and umbilical cord-derived stem cells: which is a better alternative to treat spinal cord injury?

Multiple types of stem cells have been proposed for the treatment of spinal cord injury, but their comparative information remains elusive. In this study, a rat model of T10 contusion spinal cord injury was established by the impactor method. Human umbilical cord-derived mesenchymal stem cells (UCMSCs) or human adipose tissue-derived mesenchymal stem cells (ADMSCs) (2.5 μL/injection site, 1 × 10⁵ cells/μL) was injected on rostral and caudal of the injury segment on the ninth day after injury. Rats injected with mesenchymal stem cell culture medium were used as controls. Our results show that although transplanted UCMSCs and ADMSCs failed to differentiate into neurons or glial cells in vivo, both significantly improved motor and sensory function. After spinal cord injury, UCMSCs and ADMSCs similarly promoted spinal neuron survival and axonal regeneration, decreased glial scar and lesion cavity formation, and reduced numbers of active macrophages. Bio-Plex analysis of spinal samples showed a specific increase of interleukin-10 and decrease of tumor necrosis factor α in the ADMSC group, as well as a downregulation of macrophage inflammatory protein 3α in both UCMSC and ADMSC groups at 3 days after cell transplantation. Upregulation of interleukin-10 and interleukin-13 was observed in both UCMSC and ADMSC groups at 7 days after cell transplantation. Isobaric tagging for relative and absolute quantitation proteomics analyses showed that UCMSCs and ADMSCs induced changes of multiple genes related to axonal regeneration, neurotrophy, and cell apoptosis in common and specific manners. In conclusion, UCMSC and ADMSC transplants yielded quite similar contributions to motor and sensory recovery after spinal cord injury via anti-inflammation and improved axonal growth. However, there were some differences in cytokine and gene expression induced by these two types of transplanted cells. Animal experiments were approved by the Laboratory Animal Ethics Committee at Jinan University (approval No. 20180228026) on February 28, 2018, and the application of human stem cells was approved by the Medical Ethics Committee of Medical College of Jinan University of China (approval No. 2016041303) on April 13, 2016.

Transplantation of mesenchymal stem cells overexpressing interleukin-10 induces autophagy response and promotes neuroprotection in a rat model of TBI

Autophagy, including mitophagy, is critical for neuroprotection in traumatic brain injury (TBI). Transplantation of mesenchymal stem cells (MSCs) provides neuroprotection and induces autophagy by increasing anti-inflammatory cytokines, such as interleukin-10 (IL-10). To evaluate these effects of IL10 that are released by MSCs, we genetically engineered MSCs to overexpress IL10 and compared their effects to unaltered MSCs following transplantation near the site of induced TBIs in rats. Adult, male Sprague-Dawley rats were divided into four groups: Sham + vehicle, TBI + vehicle, TBI + MSCs-IL-10 and TBI + MSCs-GFP. Thirty-six hours post-TBI, the first two groups received vehicle (Hanks balance salt solution), whereas last two groups were transplanted with MSCs-IL-10 or MSCs-GFP. Three weeks after transplantation, biomarkers for neurodegenerative changes, autophagy, mitophagy, cell death and survival markers were measured. We observed a significant increase in the number of dead cells in the cortex and hippocampus in TBI rats, whereas transplantation of MSCs-IL-10 significantly reduced their numbers in comparison to MSCs alone. MSCs-IL-10 rats had increased autophagy, mitophagy and cell survival markers, along with decreased markers for cell death and neuroinflammation. These results suggest that transplantation of MSCs-IL-10 may be an effective strategy to protect against TBI-induced neuronal damage.

Anti-aging effects exerted by Tetramethylpyrazine enhances self-renewal and neuronal differentiation of rat bMSCs by suppressing NF-kB signaling

In order to improve the therapeutic effects of mesenchymal stem cell (MSC)-based therapies for a number of intractable neurological disorders, a more favorable strategy to regulate the outcome of bone marrow MSCs (bMSCs) was examined in the present study. In view of the wide range of neurotrophic and neuroprotective effects, Tetramethylpyrazine (TMP), a biologically active alkaloid isolated from the herbal medicine Ligusticum wallichii, was used. It was revealed that treatment with 30–50 mg/l TMP for 4 days significantly increased cell viability, alleviated senescence by suppressing NF-κB signaling, and promoted bMSC proliferation by regulating the cell cycle. In addition, 40–50 mg/l TMP treatment may facilitate the neuronal differentiation of bMSCs, verified in the present study by presentation of neuronal morphology and expression of neuronal markers: microtubule-associated protein 2 (MAP-2) and neuron-specific enolase (NSE). The quantitative real-time polymerase chain reaction (qRT-PCR) revealed that TMP treatment may promote the expression of neurogenin 1 (Ngn1), neuronal differentiation 1 (NeuroD) and mammalian achaete–scute homolog 1 (Mash1). In conclusion, 4 days of 40–50 mg/l TMP treatment may significantly delay bMSC senescence by suppressing NF-κB signaling, and enhancing the self-renewal ability of bMSCs, and their potential for neuronal differentiation.

The Efficacy and Safety of Mesenchymal Stem Cell Transplantation for Spinal Cord Injury Patients: A Meta-Analysis and Systematic Review

Spinal cord injury (SCI) is a devastating disease, with a high rate of disability. In this meta-analysis, we aimed to comprehensively assess the efficacy and safety of mesenchymal stem cells (MSCs) in treating clinical SCI patients. We systematically searched the PUBMED, EMBASE, Chinese Biomedical (CBM), Web of Science and Cochrane databases using the strategy of combination of free-text words and MeSH terms. The indicators of the American Spinal Injury Association (ASIA) impairment scale (AIS)-grading improvement rate and adverse effects were displayed with an overall relative risk (RR). For the continuous variables of the ASIA motor score, light-touch score, pinprick score, activities of daily living (ADL) score, and residual urine volume, we used odds ratio (OR) to analyze the data. Eleven studies comprising 499 patients meeting all inclusion and exclusion criteria were included. No serious heterogeneity or publication bias was observed across each study. The results showed that significant improvements of total AIS grade (RR: 3.70; P < 0.001), AIS grade A (RR: 3.57; P < 0.001), ASIA sensory score (OR: 8.63; P < 0.001) and reduction of residual urine volume (OR: -36.37; P = 0.03) were observed in experimental group compared with control group. However, no significant differences of motor score (OR: 1.37, P = 0.19) and ADL score (OR: 2.61, P = 0.27) were observed between experimental and control groups. In addition, there were no serious and permanent adverse effects after cell transplantation. Cell transplantation with MSCs is effective and safe in improving the sensory and bladder functions of SCI patients.

Isolation, culture, and characterization of chicken lung-derived mesenchymal stem cells

Using lung tissues separated from 12-day-old chicken embryos, we attempted to obtain a novel population of stem cells, namely, chicken lung-derived mesenchymal stem cells (LMSCs), which exhibit spindle-like morphology. The results of colony-forming assay and population doubling assay demonstrated that LMSCs had enormous colony-forming, self-renewal, and proliferative potential. When appropriately induced, LMSCs could differentiate into osteoblasts, adypocytes, chondrocytes, and neurons; in other words, LMSCs had cross-embryonic layer differentiation potential under corresponding induction conditions. Aside from colony-forming, self-renewal, and multilineage differentiation capabilities, LMSCs were characterized by specific cell phenotypes. The results of immunohistochemistry and flow cytometry demonstrated that LMSCs consistently expressed OCT-4 - a specific gene marker expressed in pluripotent stem cells - and markers associated with MSCs such as CD29, CD73, CD90, and CD105. However, LMSCs lacked hematopoietic cell surface molecules such as CD34 and CD45. Primary LMSCs could be subcultured to passage 24 at most in vitro and karyotype analysis demonstrated that LMSCs possessed genomic stability. These unique characteristics were consistent with the characteristics of MSCs, which had been isolated from other tissues. This provides a foundation for LMSCs as a promising avenue for cellular transplantation therapy, regenerative medicine, and tissue engineering.

The Effect of Human Mesenchymal Stem Cells Derived from Wharton's Jelly in Spinal Cord Injury Treatment Is Dose-Dependent and Can Be Facilitated by Repeated Application

Human mesenchymal stem cells derived from Wharton’s jelly (WJ-MSCs) were used for the treatment of the ischemic-compression model of spinal cord injury in rats. To assess the effectivity of the treatment, different dosages (0.5 or 1.5 million cells) and repeated applications were compared. Cells or saline were applied intrathecally by lumbar puncture for one week only, or in three consecutive weeks after injury. Rats were assessed for locomotor skills (BBB, rotarod, flat beam) for 9 weeks. Spinal cord tissue was morphometrically analyzed for axonal sprouting, sparing of gray and white matter and astrogliosis. Endogenous gene expression (Gfap, Casp3, Irf5, Cd86, Mrc1, Cd163) was studied with quantitative Real-time polymerase chain reaction (qRT PCR). Significant recovery of functional outcome was observed in all of the treated groups except for the single application of the lowest number of cells. Histochemical analyses revealed a gradually increasing effect of grafted cells, resulting in a significant increase in the number of GAP43+ fibers, a higher amount of spared gray matter and reduced astrogliosis. mRNA expression of macrophage markers and apoptosis was downregulated after the repeated application of 1.5 million cells. We conclude that the effect of hWJ-MSCs on spinal cord regeneration is dose-dependent and potentiated by repeated application.

Human Mesenchymal Stromal Cell-Derived Extracellular Vesicles Modify Microglial Response and Improve Clinical Outcomes in Experimental Spinal Cord Injury

No current clinical intervention can alter the course of acute spinal cord injury (SCI), or appreciably improve neurological outcome. Mesenchymal stromal cells (MSCs) have been shown to modulate the injury sequelae of SCI largely via paracrine effects, although the mechanisms remain incompletely understood. One potential modality is through secretion of extracellular vesicles (EVs). In this study, we investigate whether systemic administration of EVs isolated from human MSCs (MSCEv) has the potential to be efficacious as an alternative to cell-based therapy for SCI. Additionally, we investigate whether EVs isolated from human MSCs stimulated with pro-inflammatory cytokines have enhanced anti-inflammatory effects when administered after SCI. Immunohistochemistry supported the quantitative analysis, demonstrating a diminished inflammatory response with apparent astrocyte and microglia disorganization in cord tissue up to 10 mm caudal to the injury site. Locomotor recovery scores showed significant improvement among animals treated with MSCEv. Significant increases in mechanical sensitivity threshold were observed in animals treated with EVs from either naïve MSC (MSCEvwt) or stimulated MSC (MSCEv+), with a statistically significant increase in threshold for MSCEv+-treated animals when compared to those that received MSCEvwt. In conclusion, these data show that treatment of acute SCI with extracellular vesicles derived from human MSCs attenuates neuroinflammation and improves functional recovery.

Defined Culture Conditions Accelerate Small-molecule-assisted Neural Induction for the Production of Neural Progenitors from Human-induced Pluripotent Stem Cells

The use of defined conditions for derivation, maintenance, and differentiation of human-induced pluripotent stem cells (hiPSCs) provides a superior experimental platform to discover culture responses to differentiation cues and elucidate the basic requirements for cell differentiation and fate restriction. Adoption of defined systems for reprogramming, undifferentiated growth, and differentiation of hiPSCs was found to significantly influence early stage differentiation signaling requirements and temporal kinetics for the production of primitive neuroectoderm. The bone morphogenic protein receptor agonist LDN-193189 was found to be necessary and sufficient for neural induction in a monolayer system with landmark antigens paired box 6 and sex-determining region Y-box 1 appearing within 72 h. Preliminary evidence suggests this neuroepithelium was further differentiated to generate ventral spinal neural progenitors that produced electrophysiologically active neurons in vitro, maintaining viability posttransplantation in an immunocompromised host. Our findings support current developments in the field, demonstrating that adoption of defined reagents for the culture and manipulation of pluripotent stem cells is advantages in terms of simplification and acceleration of differentiation protocols, which will be critical for future clinical translation.