Co-transplantation of mesenchymal and neural stem cells and overexpressing stromal-derived factor-1 for treating spinal cord injury

Combined transplantation of hiPSC-NSC and hMSC ameliorated neuroinflammation and promoted neuroregeneration in acute spinal cord injury

BACKGROUND

Spinal cord injury (SCI) is a serious clinical condition that has pathological changes such as increased neuroinflammation and nerve tissue damage, which eventually manifests as fibrosis of the injured segment and the development of a spinal cord cavity leading to loss of function. Cell-based therapy, such as mesenchymal stem cells (MSCs) and neural stem cells (NSCs) are promising treatment strategies for spinal cord injury via immunological regulation and neural replacement respectively. However, therapeutic efficacy is rare reported on combined transplantation of MSC and NSC in acute mice spinal cord injury even the potential reinforcement might be foreseen. Therefore, this study was conducted to investigate the safety and efficacy of co-transplanting of MSC and NSC sheets into an SCI mice model on the locomotor function and pathological changes of injured spinal cord.

METHODS

To evaluate the therapeutic effects of combination cells, acute SCI mice model were established and combined transplantation of hiPSC-NSCs and hMSCs into the lesion site immediately after the injury. Basso mouse scale was used to perform the open-field tests of hind limb motor function at days post-operation (dpo) 1, 3, 5, and 7 after SCI and every week after surgery. Spinal cord and serum samples were collected at dpo 7, 14, and 28 to detect inflammatory and neurotrophic factors. Hematoxylin-eosin (H&E) staining, masson staining and transmission electron microscopy were used to evaluate the morphological changes, fibrosis area and ultrastructure of the spinal cord.

RESULT

M&N transplantation reduced fibrosis formation and the inflammation level while promoting the secretion of nerve growth factor and brain-derived neurotrophic factor. We observed significant reduction in damaged tissue and cavity area, with dramatic improvement in the M&N group. Compared with the Con group, the M&N group exhibited significantly improved behaviors, particularly limb coordination.

CONCLUSION

Combined transplantation of hiPSC-NSC and hMSC could significantly ameliorate neuroinflammation, promote neuroregeneration, and decrease spinal fibrosis degree in safe and effective pattern, which would be indicated as a novel potential cell treatment option.

Neural stem cell therapies for spinal cord injury repair: an update on recent preclinical and clinical advances

Traumatic spinal cord injury (SCI) is a leading cause of lifelong disabilities. Permanent sensory, motor and autonomic impairments after SCI are substantially attributed to degeneration of spinal cord neurons and axons, and disintegration of neural network. To date, minimal regenerative treatments are available for SCI with an unmet need for new therapies to reconstruct the damaged spinal cord neuron-glia network and restore connectivity with the supraspinal pathways. Multipotent neural precursor cells (NPCs) have a unique capacity to generate neurons, oligodendrocytes and astrocytes. Due to this capacity, NPCs have been an attractive cell source for cellular therapies for SCI. Transplantation of NPCs has been extensively tested in preclinical models of SCI in the past two decades. These studies have identified opportunities and challenges associated with NPC therapies. While NPCs have the potential to promote neuroregeneration through various mechanisms, their low long-term survival and integration within the host injured spinal cord limit the functional benefits of NPC-based therapies for SCI. To address this challenge, combinatorial strategies have been developed to optimize the outcomes of NPC therapies by enriching SCI microenvironment through biomaterials, genetic and pharmacological therapies. In this review, we will provide an in-depth discussion on recent advances in preclinical NPC-based therapies for SCI. We will discuss modes of actions and mechanism by which engrafted NPCs contribute to the repair process and functional recovery. We will also provide an update on current clinical trials and new technologies that have facilitated preparation of medical-grade human NPCs suitable for transplantation in clinical studies.

Efficacy of growth factor gene-modified stem cells for motor function after spinal cord injury in rodents: a systematic review and meta‑analysis

The efficacy of growth factor gene-modified stem cells in treating spinal cord injury (SCI) remains unclear. This study aims to evaluate the effectiveness of growth factor gene-modified stem cells in restoring motor function after SCI. Two reviewers searched four databases, including PubMed, Embase, Web of Science, and Scopus, to identify relevant records. Studies on rodents assessing the efficacy of transplanting growth factor gene-modified stem cells in restoring motor function after SCI were included. The results were reported using the standardized mean difference (SMD) with a 95% confidence interval (95% CI). Analyses showed that growth factor gene-modified stem cell transplantation improved motor function recovery in rodents with SCI compared to the untreated (SMD = 3.98, 95% CI 3.26-4.70, I2 = 86.8%, P < 0.0001) and stem cell (SMD = 2.53, 95% CI 1.93-3.13, I2 = 86.9%, P < 0.0001) groups. Using growth factor gene-modified neural stem/histone cells enhanced treatment efficacy. In addition, the effectiveness increased when viral vectors were employed for gene modification and high transplantation doses were administered during the subacute phase. Stem cells derived from the human umbilical cord exhibited an advantage in motor function recovery. However, the transplantation of growth factor gene-modified stem cells did not significantly improve motor function in male rodents (P = 0.136). Transplantation of growth factor gene-modified stem cells improved motor function in rodents after SCI, but claims of enhanced efficacy should be approached with caution. The safety of gene modification remains a significant concern, requiring additional efforts to enhance its clinical translatability.

Perinatal Tissue-Derived Stem Cells: An Emerging Therapeutic Strategy for Challenging Neurodegenerative Diseases

Over the past 20 years, stem cell therapy has been considered a promising option for treating numerous disorders, in particular, neurodegenerative disorders. Stem cells exert neuroprotective and neurodegenerative benefits through different mechanisms, such as the secretion of neurotrophic factors, cell replacement, the activation of endogenous stem cells, and decreased neuroinflammation. Several sources of stem cells have been proposed for transplantation and the restoration of damaged tissue. Over recent decades, intensive research has focused on gestational stem cells considered a novel resource for cell transplantation therapy. The present review provides an update on the recent preclinical/clinical applications of gestational stem cells for the treatment of protein-misfolding diseases including Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD) and amyotrophic lateral sclerosis (ALS). However, further studies should be encouraged to translate this promising therapeutic approach into the clinical setting.

Challenges in Translating Regenerative Therapies for Spinal Cord Injury

Regenerating the injured spinal cord is a substantial challenge with many obstacles that need to be overcome to achieve robust functional benefits. This abundance of hurdles can partly explain the limited success when applying regenerative intervention treatments in animal models and/or people. In this article, we elaborate on a few of these obstacles, starting with the applicability of animal models and how they compare to the clinical setting. We then discuss the requirement for combinatorial interventions and the associated problems in experimental design, including the addition of rehabilitative training. The article expands on differences in lesion sizes and locations between humans and common animal models, and how this difference can determine the success or failure of an intervention. An additional and frequently overlooked problem in the translation of interventions that applies beyond the field of neuroregeneration is the reporting bias and the lack of transparency in reporting findings. New data mandates are tackling this problem and will eventually result in a more balanced view of the field. Finally, we will discuss strategies to negotiate the challenging course of successful translation to facilitate successful translation of regeneration promoting interventions.

Cell transplantation therapies for spinal cord injury focusing on bone marrow mesenchymal stem cells: Advances and challenges

Spinal cord injury (SCI) is a devastating condition with complex pathological mechanisms that lead to sensory, motor, and autonomic dysfunction below the site of injury. To date, no effective therapy is available for the treatment of SCI. Recently, bone marrow-derived mesenchymal stem cells (BMMSCs) have been considered to be the most promising source for cellular therapies following SCI. The objective of the present review is to summarize the most recent insights into the cellular and molecular mechanism using BMMSC therapy to treat SCI. In this work, we review the specific mechanism of BMMSCs in SCI repair mainly from the following aspects: Neuroprotection, axon sprouting and/or regeneration, myelin regeneration, inhibitory microenvironments, glial scar formation, immunomodulation, and angiogenesis. Additionally, we summarize the latest evidence on the application of BMMSCs in clinical trials and further discuss the challenges and future directions for stem cell therapy in SCI models.

Multiple strategies enhance the efficacy of MSCs transplantation for spinal cord injury

Spinal cord injury (SCI) is a serious complication of the central nervous system (CNS) after spine injury, often resulting in severe sensory, motor, and autonomic dysfunction below the level of injury. To date, there is no effective treatment strategy for SCI. Recently, stem cell therapy has brought hope to patients with neurological diseases. Mesenchymal stem cells (MSCs) are considered to be the most promising source of cellular therapy after SCI due to their immunomodulatory, neuroprotective and angiogenic potential. Considering the limited therapeutic effect of MSCs due to the complex pathophysiological environment following SCI, this paper not only reviews the specific mechanism of MSCs to facilitate SCI repair, but also further discusses the research status of these pluripotent stem cells combined with other therapeutic approaches to promote anatomical and functional recovery post-SCI.

Interaction of Neural Stem Cells (NSCs) and Mesenchymal Stem Cells (MSCs) as a Promising Approach in Brain Study and Nerve Regeneration

Rapid developments in stem cell research in recent years have provided a solid foundation for their use in medicine. Over the last few years, hundreds of clinical trials have been initiated in a wide panel of indications. Disorders and injuries of the nervous system still remain a challenge for the regenerative medicine. Neural stem cells (NSCs) are the optimal cells for the central nervous system restoration as they can differentiate into mature cells and, most importantly, functional neurons and glial cells. However, their application is limited by multiple factors such as difficult access to source material, limited cells number, problematic, long and expensive cultivation in vitro, and ethical considerations. On the other hand, according to the available clinical databases, most of the registered clinical trials involving cell therapies were carried out with the use of mesenchymal stem/stromal/signalling cells (MSCs) obtained from afterbirth or adult human somatic tissues. MSCs are the multipotent cells which can also differentiate into neuron-like and glia-like cells under proper conditions in vitro; however, their main therapeutic effect is more associated with secretory and supportive properties. MSCs, as a natural component of cell niche, affect the environment through immunomodulation as well as through the secretion of the trophic factors. In this review, we discuss various therapeutic strategies and activated mechanisms related to bilateral MSC–NSC interactions, differentiation of MSCs towards the neural cells (subpopulation of crest-derived cells) under the environmental conditions, bioscaffolds, or co-culture with NSCs by recreating the conditions of the neural cell niche.

Human-Induced Neural and Mesenchymal Stem Cell Therapy Combined with a Curcumin Nanoconjugate as a Spinal Cord Injury Treatment

We currently lack effective treatments for the devastating loss of neural function associated with spinal cord injury (SCI). In this study, we evaluated a combination therapy comprising human neural stem cells derived from induced pluripotent stem cells (iPSC-NSC), human mesenchymal stem cells (MSC), and a pH-responsive polyacetal-curcumin nanoconjugate (PA-C) that allows the sustained release of curcumin. In vitro analysis demonstrated that PA-C treatment protected iPSC-NSC from oxidative damage in vitro, while MSC co-culture prevented lipopolysaccharide-induced activation of nuclear factor-κB (NF-κB) in iPSC-NSC. Then, we evaluated the combination of PA-C delivery into the intrathecal space in a rat model of contusive SCI with stem cell transplantation. While we failed to observe significant improvements in locomotor function (BBB scale) in treated animals, histological analysis revealed that PA-C-treated or PA-C and iPSC-NSC + MSC-treated animals displayed significantly smaller scars, while PA-C and iPSC-NSC + MSC treatment induced the preservation of β-III Tubulin-positive axons. iPSC-NSC + MSC transplantation fostered the preservation of motoneurons and myelinated tracts, while PA-C treatment polarized microglia into an anti-inflammatory phenotype. Overall, the combination of stem cell transplantation and PA-C treatment confers higher neuroprotective effects compared to individual treatments.

Adipose-derived stromal cells improve functional recovery after spinal cord injury through TGF-β1/Smad3/PLOD2 pathway activation

Transplantation of mesenchymal stromal cells (MSCs) improves functional recovery in experimental models of spinal cord injury (SCI), but the mechanism is not fully understood. Activation of procollagen-lysine, 2-oxoglutarate 5-dioxygenase 2 (PLOD2), a collagen-modifying enzyme, reportedly follows MSC transplantation in an SCI animal model. We investigated the regulation of PLOD2 expression and its potential contribution to the neuroprotective effects of adipose-derived stromal cells (ADSCs) following mechanical injury to neurons in vitro and SCI in vivo. ADSCs enhanced wound healing in vitro and promoted functional recovery after their implantation near injury sites in a rat SCI model. These effects correlated with upregulation of PLOD2, MAP2, NSE and GAP43, and downregulation of GFAP, which is indicative of improved neuronal survival and axonal regeneration as well as reduced glial scar formation. The neurorestorative effect of ADSCs was weakened after inhibition of PLOD2 expression. ADSCs appeared to induce PLOD2 upregulation via TGF-β1 secretion, as ADSC-mediated PLOD2 expression, neuronal survival, and functional recovery after SCI were largely prevented by SB431542, a TGF-(1 receptor inhibitor. These findings indicate that ADSCs reduce lesion size and promote functional recovery after SCI mainly through activation of a TGF-β1/P-Samd3/PLOD2 pathway in spinal cord neurons.

MSC spheroids-loaded collagen hydrogels simultaneously promote neuronal differentiation and suppress inflammatory reaction through PI3K-Akt signaling pathway

It is critical for the clinical success to take the anti-inflammatory function into consideration when integrating the neurogenesis into the nerve repair materials. To this aim, we prepared mesenchymal stem cell (MSC) spheroids-loaded collagen (Col) hydrogels with combined superior anti-inflammatory efficacy and neurogenic activity. The size of the MSC spheroids showed a strong modulation effect on both functions, and the MSC spheroids-100 sample exhibited the best neuronal and anti-inflammatory potentials. The observed dual functions were likely based on the elevated intrinsic cell-cell contacts and cell-extracellular matrix interactions from the MSC spheroids. MSC self-assembly as spheroids expedited the secretions of endogenous trophic factors and extracellular matrix (ECM), which was beneficial to drive neural stem cell differentiation into the neuronal lineage. In addition, the formation of the MSC spheroids secreted more amounts and types of cytokines as well as immunomodulatory paracrine factors to suppress LPS-induced inflammatory reaction. LC-MS/MS analysis further demonstrated that MSC spheroids contributed to the activation of neuroactive ligand-receptor interaction, thereby triggering downstream PI3K-Akt signal pathway, which was likely due to the acceleration of ECM-receptor interaction, gap junction and tight junction. Importantly, inhibiting Akt pathway significantly suppressed the neuronal differentiation, indicating that PI3K-Akt signal pathway was critically involved in the Col-MSC spheroid hydrogel mediated neuroprotection and neurogenesis. Such findings not only provided a simple approach for improving MSC-based therapies for neuron-related diseases, but also shed insight on understanding the underlying mechanisms of MSC-mediated neuronal differentiation.

Ginsenoside Rg1 prevents vascular intimal hyperplasia involved by SDF-1α/CXCR4, SCF/c-kit and FKN/CX3CR1 axes in a rat balloon injury

ETHNOPHARMACOLOGICAL RELEVANCE

Panax ginseng C. A. Mey. is a traditional tonic that has been used for thousands of years, and has positive effects on vascular diseases. Ginsenoside Rg1 (GS-Rg1) is one of the active ingredients of Panax ginseng C. A. Mey. and has been shown to have beneficial effects against ischemia/reperfusion injury. Our previously study has found that GS-Rg1 can mobilize bone marrow stem cells and inhibit vascular smooth muscle proliferation and phenotype transformation. However, pharmacological effects and mechanism of GS-Rg1 in inhibiting intimal hyperplasia is still unknown.

AIM OF THE STUDY

This study was aimed to investigate whether GS-Rg1 prevented vascular intimal hyperplasia, and the involvement of stromal cell-derived factor-1α (SDF-1α)/CXCR4, stem cell factor (SCF)/c-kit and fractalkine (FKN)/CX3CR1 axes.

MATERIALS AND METHODS

Rats were operated with carotid artery balloon injury. The treatment groups were injected with 4, 8 and 16 mg/kg of GS-Rg1 for 14 days. The degree of intimal hyperplasia was evaluated by histopathological examination. The expression of α-SMA (α-smooth muscle actin) and CD133 were detected by double-label immunofluorescence. Serum levels of SDF-1α, SCF and soluble FKN (sFKN) were detected by enzyme linked immunosorbent assay (ELISA). The protein expressions of SCF, SDF-1α and FKN, as well as the receptors c-kit, CXC chemokine receptor type 4 (CXCR4) and CX3C chemokine receptor type 1 (CX3CR1) were detected by immunochemistry.

RESULTS

GS-Rg1 reduced intimal hyperplasia by evidence of the values of NIA, the ratio of NIA/MA, and the ratio of NIA/IELA and the ratio of NIA/LA, especially in 16 mg/kg group. Furthermore, GS-Rg1 8 mg/kg group and 16 mg/kg group decreased the protein expressions of the SDF-1α/CXCR4, SCF/c-kit and FKN/CX3CR1 axes in neointima, meanwhile GS-Rg1 8 mg/kg group and 16 mg/kg group also attenuated the expressions of SDF-1α, SCF and sFKN in serum. In addition, the expression of α-SMA and CD133 marked smooth muscle progenitor cells (SMPCs) was decreased after GS-Rg1 treatment.

CONCLUSIONS

GS-Rg1 has a positive effect on inhibiting vascular intimal hyperplasia, and the underlying mechanism is related to inhibitory expression of SDF-1α/CXCR4, SCF/c-kit and FKN/CX3CR1 axes.

Remarkable migration propensity of dental pulp stem cells towards neurodegenerative milieu: An in vitro analysis

Stem cell therapy provides a ray of hope for treating neurodegenerative diseases (ND). Bone marrow mesenchymal stem cells (BM-MSC) were extensively investigated for their role in neuroregeneration. However, drawbacks like painful bone marrow extraction, less proliferation and poor CNS engraftment following systemic injections of BM-MSC prompt us to search for alternate/appropriate source of MSC for treating ND. In this context, dental pulp stem cells (DPSC) could be an alternative to BM-MSC as it possess both mesenchymal and neural characteristic features due to its origin from ectoderm, ease of isolation, higher proliferation index and better neuroprotection. A study on the migration potential of DPSC compared to BM-MSC in a neurodegenerative condition is warranted. Given the neural crest origin, we hypothesize that DPSC possess better migration towards neurodegenerative milieu as compared to BM-MSC. In this prospect, we investigated the migration potential of DPSC in an in vitro neurodegenerative condition. Towards this, transwell, Matrigel and chorioallantoic membrane (CAM) migration assays were carried-out by seeding hippocampal neurons in the lower chamber and treated with 300 μM kainic acid (KA) for 6 h to induce neurodegeneration. Subsequently, the upper chamber of transwell was loaded with DPSC/BM-MSC and their migration potential was assessed following 24 h of incubation. Our results revealed that the migration potential of DPSC/BM-MSC was comparable in non-degenerative condition. However, following injury the migration potential of DPSC towards the degenerating site was significantly higher as compared to BM-MSC. Furthermore, upon exposure of naïve DPSC/BM-MSCs to culture medium derived from neurodegenerative milieu resulted in significant upregulation of homing factors like SDF-1alpha, CXCR-4, VCAM-1, VLA-4, CD44, MMP-2 suggesting that the superior migration potential of DPSC might be due to prompt expression of homing factors in DPSC compared to BM-MSCs.

Genetic Engineering as a Strategy to Improve the Therapeutic Efficacy of Mesenchymal Stem/Stromal Cells in Regenerative Medicine

Mesenchymal stem/stromal cells (MSCs) have been widely studied in the field of regenerative medicine for applications in the treatment of several disease settings. The therapeutic potential of MSCs has been evaluated in studies in vitro and in vivo, especially based on their anti-inflammatory and pro-regenerative action, through the secretion of soluble mediators. In many cases, however, insufficient engraftment and limited beneficial effects of MSCs indicate the need of approaches to enhance their survival, migration and therapeutic potential. Genetic engineering emerges as a means to induce the expression of different proteins and soluble factors with a wide range of applications, such as growth factors, cytokines, chemokines, transcription factors, enzymes and microRNAs. Distinct strategies have been applied to induce genetic modifications with the goal to enhance the potential of MCSs. This review aims to contribute to the update of the different genetically engineered tools employed for MSCs modification, as well as the factors investigated in different fields in which genetically engineered MSCs have been tested.

Is the Immunological Response a Bottleneck for Cell Therapy in Neurodegenerative Diseases?

Neurodegenerative disorders such as Parkinson's (PD) and Huntington's disease (HD) are characterized by a selective detrimental impact on neurons in a specific brain area. Currently, these diseases have no cures, although some promising trials of therapies that may be able to slow the loss of brain cells are underway. Cell therapy is distinguished by its potential to replace cells to compensate for those lost to the degenerative process and has shown a great potential to replace degenerated neurons in animal models and in clinical trials in PD and HD patients. Fetal-derived neural progenitor cells, embryonic stem cells or induced pluripotent stem cells are the main cell sources that have been tested in cell therapy approaches. Furthermore, new strategies are emerging, such as the use of adult stem cells, encapsulated cell lines releasing trophic factors or cell-free products, containing an enriched secretome, which have shown beneficial preclinical outcomes. One of the major challenges for these potential new treatments is to overcome the host immune response to the transplanted cells. Immune rejection can cause significant alterations in transplanted and endogenous tissue and requires immunosuppressive drugs that may produce adverse effects. T-, B-lymphocytes and microglia have been recognized as the main effectors in striatal graft rejection. This review aims to summarize the preclinical and clinical studies of cell therapies in PD and HD. In addition, the precautions and strategies to ensure the highest quality of cell grafts, the lowest risk during transplantation and the reduction of a possible immune rejection will be outlined. Altogether, the wide-ranging possibilities of advanced therapy medicinal products (ATMPs) could make therapeutic treatment of these incurable diseases possible in the near future.

Thermosensitive bFGF-Modified Hydrogel with Dental Pulp Stem Cells on Neuroinflammation of Spinal Cord Injury

Acute spinal cord injury (SCI) induces severe neuroinflammation, which increases intermediary filaments and neurodegeneration. Previous studies have shown that a basic fibroblast growth factor (bFGF) and dental pulp stem cells (DPSCs) contribute to a protective effect on injured neuronal cells, but the mechanism of SCI repair is still unclear. In this study, in situ heparin (HeP) hydrogel injection containing bFGF and DPSCs (HeP-bFGF-DPSCs), as well as in vitro studies of bFGF and DPSCs, proved an effective control over inflammation. The in vivo application of HeP-bFGF-DPSCs regulated inflammatory reactions and accelerated the nerve regeneration through microtubule stabilization and tissue vasculature. Our mechanistic investigation also showed that bFGF-DPSCs treatment inhibited microglia/macrophage proliferation and activation. Furthermore, HeP-bFGF-DPSCs prevented microglia/macrophage activation and reduced proinflammatory cytokine release. In this paper, we discovered that bFGF and DPSCs worked together to attenuate tissue inflammation of the injured spinal cord, resulting in a superior nerve repair. Our results indicated that a thermosensitive hydrogel delivering bFGF and DPSCs could serve as a promising treatment option for spinal cord injuries.

Protective effect of brain-derived neurotrophic factor and neurotrophin-3 overexpression by adipose-derived stem cells combined with silk fibroin/chitosan scaffold in spinal cord injury

Objectives: Spinal cord injury (SCI) is a most debilitating traumatic injury, and cytotherapy is a promising alternative treatment strategy. Here we investigated the effect and mechanism of adipose-derived stem/stromal cells (ASCs) with overexpressing brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT3) (BDNF-NT3) in combination with silk fibroin/chitosan scaffold (SFCS) in SCI.Methods: Female Sprague-Dawley rats were used as an SCI model. SFCS,SFCS and ASCs, or ASCs overexpressing NT3, BDNF, and BDNF-NT3 were implanted into SCI rats. Basso, Beattie, and Bresnahan score, pathological changes, and spinal cord tissue and nerve fiber morphology were observed and assayed. GAP-43, GFAP, and caspase-3 expression was determined using immunohistochemistry and western blotting.Results: Smoother spinal cords, less scar tissue, and lower inflammatory activity were found in the SFCS, SFCS and ASCs, ASCs with NT3, BDNF, and BDNF-NT3 overexpression treatment than in the untreated SCI rat groups. Increasing formation of nerve fibers was observed in the above groups in order. GAP-43 expression significantly increased, while GFAP and caspase-3 expression significantly decreased. These results indicated obvious alleviation in pathological changes and BDNF-NT3 overexpression in ASCs combined with SFCS treatment in SCI rats.Conclusion: Thus, BDNF-NT3 overexpression from ASCs with SFCS had synergistic neuroprotective effects on SCI and may be a treatment option for SCI.

Effects of neural stem cell transplantation on the motor function of rats with contusion spinal cord injuries: a meta-analysis

Objective

To judge the efficacies of neural stem cell (NSC) transplantation on functional recovery following contusion spinal cord injuries (SCIs).

Data sources

Studies in which NSCs were transplanted into a clinically relevant, standardized rat model of contusion SCI were identified by searching the PubMed, Embase and Cochrane databases, and the extracted data were analyzed by Stata 14.0.

Data selection

Inclusion criteria were that NSCs were used in in vivo animal studies to treat contusion SCIs and that behavioral assessment of locomotor functional recovery was performed using the Basso, Beattie, and Bresnahan lo-comotor rating scale. Exclusion criteria included a follow-up of less than 4 weeks and the lack of control groups.

Outcome measures

The restoration of motor function was assessed by the Basso, Beattie, and Bresnahan locomotor rating scale.

Results

We identified 1756 non-duplicated papers by searching the aforementioned electronic databases, and 30 full-text articles met the inclusion criteria. A total of 37 studies reported in the 30 articles were included in the meta-analysis. The meta-analysis results showed that transplanted NSCs could improve the motor function recovery of rats following contusion SCIs, to a moderate extent (pooled standardized mean difference (SMD) = 0.73; 95% confidence interval (CI): 0.47-1.00; P < 0.001). NSCs obtained from different donor species (rat: SMD = 0.74; 95% CI: 0.36-1.13; human: SMD = 0.78; 95% CI: 0.31-1.25), at different donor ages (fetal: SMD = 0.67; 95% CI: 0.43-0.92; adult: SMD = 0.86; 95% CI: 0.50-1.22) and from different origins (brain-derived: SMD = 0.59; 95% CI: 0.27-0.91; spinal cord-derived: SMD = 0.51; 95% CI: 0.22-0.79) had similar efficacies on improved functional recovery; however, adult induced pluripotent stem cell-derived NSCs showed no significant efficacies. Furthermore, the use of higher doses of transplanted NSCs or the administration of immunosuppressive agents did not promote better locomotor function recovery (SMD = 0.45; 95% CI: 0.21-0.70). However, shorter periods between the contusion induction and the NSC transplantation showed slightly higher efficacies (acute: SMD = 1.22; 95% CI: 0.81-1.63; subacute: SMD = 0.75; 95% CI: 0.42-1.09). For chronic injuries, NSC implantation did not significantly improve functional recovery (SMD = 0.25; 95% CI: -0.16 to 0.65).

Conclusion

NSC transplantation alone appears to be a positive yet limited method for the treatment of contusion SCIs.

Mitochondria as central regulators of neural stem cell fate and cognitive function

Emerging evidence now indicates that mitochondria are central regulators of neural stem cell (NSC) fate decisions and are crucial for both neurodevelopment and adult neurogenesis, which in turn contribute to cognitive processes in the mature brain. Inherited mutations and accumulated damage to mitochondria over the course of ageing serve as key factors underlying cognitive defects in neurodevelopmental disorders and neurodegenerative diseases, respectively. In this Review, we explore the recent findings that implicate mitochondria as crucial regulators of NSC function and cognition. In this respect, mitochondria may serve as targets for stem-cell-based therapies and interventions for cognitive defects.

White matter repair and treatment strategy after intracerebral hemorrhage

The predilection site of intracerebral hemorrhage (ICH) is in the basal ganglia, which is rich in white matter (WM) fiber bundles, such as cerebrospinal tract in the internal capsule. ICH induced damage to this area can easily lead to severe neurological dysfunction and affects the prognosis and quality of life of patients. At present, the pathophysiological mechanisms of white matter injury (WMI) after ICH have attracted researchers' attention, but studies on the repair and recovery mechanisms and therapy strategies remain rare. In this review, we mainly summarized the WM recovery and treatment strategies after ICH by updating the WMI-related content by reviewing the latest researches and proposing the bottleneck of the current research.

Mesenchymal stem cells: Cell therapy and regeneration potential

Rapid advances in the isolation of multipotent progenitor cells, routinely called mesenchymal stromal/stem cells (MSCs), from various human tissues and organs have provided impetus to the field of cell therapy and regenerative medicine. The most widely studied sources of MSCs include bone marrow, adipose, muscle, peripheral blood, umbilical cord, placenta, fetal tissue, and amniotic fluid. According to the standard definition of MSCs, these clonal cells adhere to plastic, express cluster of differentiation (CD) markers such as CD73, CD90, and CD105 markers, and can differentiate into adipogenic, chondrogenic, and osteogenic lineages in vitro. However, isolated MSCs have been reported to vary in their potency and self-renewal potential. As a result, the MSCs used for clinical applications often lead to variable or even conflicting results. The lack of uniform characterization methods both in vitro and in vivo also contributes to this confusion. Therefore, the name "MSCs" itself has been increasingly questioned lately. As the use of MSCs is expanding rapidly, there is an increasing need to understand the potential sources and specific potencies of MSCs. This review discusses and compares the characteristics of MSCs and suggests that the variations in their distinctive features are dependent on the source and method of isolation as well as epigenetic changes during maintenance and growth. We also discuss the potential opportunities and challenges of MSC research with the hope to stimulate their use for therapeutic and regenerative medicine.

The combined effect of mesenchymal stem cells and resveratrol on type 1 diabetic neuropathy

Diabetic neuropathy (DN) is one of the most common diabetic complications that results in an increase in patient discomfort and pain. The present study demonstrated that mesenchymal stem cells (MSCs) or resveratrol (RSV) may improve diabetic hyperglycemia and neuropathy. The aim of the present study was to investigate the combined effect of MSCs and RSV on DN. A total of 100 non-obese diabetic mice were divided into the following six groups: Normal control, MSCs, RSV, MSCs + RSV, insulin and diabetic control groups. Following homologous therapy, the levels of blood glucose and C-peptide, islets, nuclear factor (NF)-κB, nerve growth factor (NGF) and myelin basic protein (MBP), and the sciatic nerve structure in each group were examined and evaluated. Following the administration of therapy, the levels of blood glucose and C-peptide in mice in the MSCs + RSV group were significantly improved when compared with the other diabetic groups, and the dosage of insulin therapy required was the lowest among the six experimental groups (P<0.05). The levels of NGF, MBP and NF-κB in the MSCs + RSV group were significantly improved compared with the MSCs and RSV groups (P<0.05). Furthermore, the diameter of the axon, number of myelinated nerve fibers and the depth of the myelin sheath in the MSCs + RSV group were greatest among the five examined groups (excluding the control). The combination of RSV and MSCs could relieve hyperglycemia and improve DN. This indicated that the combination of RSV and MSCs may be a novel therapeutic method for the treatment of DN.

Intraurethral co-transplantation of bone marrow mesenchymal stem cells and muscle-derived cells improves the urethral closure

Background

Cell therapy constitutes an attractive alternative to treat stress urinary incontinence. Although promising results have been demonstrated in this field, the procedure requires further optimization. The most commonly proposed cell types for intraurethral injections are muscle derived cells (MDCs) and mesenchymal stem/stromal cell (MSCs). The aim of this study was to evaluate the effects of MDC-MSC co-transplantation into the urethra.

Methods

Autologous transplantation of labeled MDCs, bone marrow MSCs or co-transplantation of MDC-MSC were performed in aged multiparous female goats (n = 6 in each group). The mean number of cells injected per animal was 29.6 × 10⁶(± 4.3 × 10⁶). PBS-injected animals constituted the control group (n = 5). Each animal underwent urethral pressure profile (UPP) measurements before and after the injection procedure. The maximal urethral closure pressure (MUCP) and functional area (FA) of UPPs were calculated. The urethras were collected at the 28th or the 84th day after transplantation. The marker fluorochrome (DID) was visualized and quantified using in vivo imaging system in whole explants. Myogenic differentiation of the graft was immunohistochemically evaluated.

Results

The grafted cells were identified in all urethras collected at day 28 regardless of injected cell type. At this time point the strongest DID-derived signal (normalized to the number of injected cells) was noted in the co-transplanted group. There was a distinct decline in signal intensity between day 28 and day 84 in all types of transplantation. Both MSCs and MDCs contributed to striated muscle formation if transplanted directly to the external urethral sphincter. In the MSC group those events were rare. If cells were injected into the submucosal region they remained undifferentiated usually packed in clearly distinguishable depots. The mean increase in MUCP after transplantation in comparison to the pre-transplantation state in the MDC, MSC and MDC-MSC groups was 12.3% (± 11.2%, not significant (ns)), 8.2% (± 9.6%, ns) and 24.1% (± 3.1%, p = 0.02), respectively. The mean increase in FA after transplantation in the MDC, MSC and MDC-MSC groups amounted to 17.8% (± 15.4%, ns), 15.2% (± 12.9%, ns) and 17.8% (± 2.5%, p = 0.04), respectively.

Conclusions

The results suggest that MDC-MSC co-transplantation provides a greater chance of improvement in urethral closure than transplantation of each population alone.

Hydrogel-Based Bioprocess for Scalable Manufacturing of Human Pluripotent Stem Cell-Derived Neural Stem Cells

Neural stem cells derived from human pluripotent stem cells (hPSC-NSCs) are of great value for modeling diseases, developing drugs, and treating neurological disorders. However, manufacturing high-quantity and -quality hPSC-NSCs, especially for clinical applications, remains a challenge. Here, we report a chemically defined, high-yield, and scalable bioprocess for manufacturing hPSC-NSCs. hPSCs are expanded and differentiated into NSCs in microscale tubes made with alginate hydrogels. The tubes are used to isolate cells from the hydrodynamic stresses in the culture vessel and limit the radial diameter of the cell mass to less than 400 μm to ensure efficient mass transport during the culture. The hydrogel tubes provide uniform, reproducible, and cell-friendly microspaces and microenvironments for cells. With this new technology, we showed that hPSC-NSCs could be produced in 12 days with high viability (∼95%), high purity (>90%), and high yield (∼5 × 10⁸ cells/mL of microspace). The volumetric yield is about 250 times more than the current state-of-the-art. Whole transcriptome analysis and quantitative real-time polymerase chain reaction showed that hPSC-NSCs made by this process had a similar gene expression to hPSC-NSCs made by the conventional culture technology. The produced hPSC-NSCs could mature into both neurons and glial cells in vitro and in vivo. The process developed in this paper can be used to produce large numbers of hPSC-NSCs for various biomedical applications in the future.

Bone marrow mesenchymal stem cells (BMSCs) improved functional recovery of spinal cord injury partly by promoting axonal regeneration

Spinal cord injury (SCI) disrupts the spinal cord and results in the loss of sensory and motor function below the lesion site. The treatment of SCI became a challenge because the injured neurons fail to axon regenerate and repair after injury. Promoting axonal regeneration plays a key role in the treatment strategies for SCI. It would meet the goal of reconstruction the injured spinal cord and improving the functional recovery. Bone marrow mesenchymal stem cells (BMSCs) are attractive therapeutic potential cell sources for SCI, and it could rebuild the injured spinal cord through neuroprotection, neural regeneration and remyelinating. Evidence has demonstrated that BMSCs play important roles in mediating axon regeneration, and glial scar formation after SCI in animal experiments and some clinical trials. We reviewed the role of BMSCs in regulating axon regeneration and glial scar formation after SCI. BMSCs based therapies may provide a therapeutic potential for the injured spinal cord by promoting axonal regeneration and repair.

Induced Pluripotent Stem Cell-Derived Neural Stem Cell Transplantations Reduced Behavioral Deficits and Ameliorated Neuropathological Changes in YAC128 Mouse Model of Huntington's Disease

Huntington's disease (HD) is a genetic neurodegenerative disorder characterized by neuronal loss and motor dysfunction. Although there is no effective treatment, stem cell transplantation offers a promising therapeutic strategy, but the safety and efficacy of this approach needs to be optimized. The purpose of this study was to test the potential of intra-striatal transplantation of induced pluripotent stem cell-derived neural stem cells (iPS-NSCs) for treating HD. For this purpose, we developed mouse adenovirus-generated iPSCs, differentiated them into neural stem cells in vitro, labeled them with Hoechst, and transplanted them bilaterally into striata of 10-month old wild type (WT) and HD YAC128 mice. We assessed the efficiency of these transplanted iPS-NSCs to reduce motor deficits in YAC128 mice by testing them on an accelerating rotarod task at 1 day prior to transplantation, and then weekly for 10 weeks. Our results showed an amelioration of locomotor deficits in YAC128 mice that received iPS-NSC transplantations. Following testing, the mice were sacrificed, and their brains were analyzed using immunohistochemistry and Western blot (WB). The results from our histological examinations revealed no signs of tumors and evidence that many iPS-NSCs survived and differentiated into region-specific neurons (medium spiny neurons) in both WT and HD mice, as confirmed by co-labeling of Hoechst-labeled transplanted cells with NeuN and DARPP-32. Also, counts of Hoechst-labeled cells revealed that a higher proportion were co-labeled with DARPP-32 and NeuN in HD-, compared to WT- mice, suggesting a dissimilar differentiation pattern in HD mice. Whereas significant decreases were found in counts of NeuN- and DARPP-32-labeled cells, and for neuronal density measures in striata of HD vehicle controls, such decrements were not observed in the iPS-NSCs-transplanted-HD mice. WB analysis showed increase of BDNF and TrkB levels in striata of transplanted HD mice compared to HD vehicle controls. Collectively, our data suggest that iPS-NSCs may provide an effective option for neuronal replacement therapy in HD.