Progress in Stem Cell Therapy for Spinal Cord Injury

Mechanisms of nitric oxide in spinal cord injury

Spinal cord injury (SCI) is a primary lesion of the spinal cord that results from external forces or diseases, accompanied by a cascade of secondary events. Nitric oxide, an endogenous gas that functions as a signaling molecule in the human body, plays a crucial role in vasodilation of smooth muscles, regulation of blood flow and pressure, and inflammatory response. This article provides a comprehensive overview of the involvement of nitric oxide in SCI and highlights recent advances in basic research on pharmacological agents that inhibit nitric oxide elevation after SCI, offering valuable insights for future therapeutic interventions targeting SCI.

Safety and feasibility of intravenous administration of a single dose of allogenic-Muse cells to treat human cervical traumatic spinal cord injury: a clinical trial

INTRODUCTION

Spinal cord injury (SCI) is a devastating injury and remains one of the largest medical and social burdens because of its intractable nature. According to the recent advances in stem cell biology, the possibility of spinal cord regeneration and functional restoration has been suggested by introducing appropriate stem cells. Multilineage-differentiating stress enduring (Muse) cells are a type of nontumorigenic endogenous reparative stem cell. The positive results of Muse cell transplantation for SCI was shown previously. As a first step for clinical application in human SCI, we conducted a clinical trial aiming to confirm the safety and feasibility of intravenously injected donor-Muse cells.

METHODS

The study design of the current trial was a prospective, multicenter, nonrandomized, nonblinded, single-arm study. The clinical trial registration number was JRCT1080224764. Patients with a cervical SCI with a neurological level of injury C4 to C7 with the severity of modified Frankel classification B1 and B2 were included. A primary endpoint was set for safety and feasibility. Our protocol was approved by the PMDA, and the trial was funded by the Life Science Institute, Tokyo, Japan. The present clinical trial recruited 10 participants (8 males and 2 females) with an average age of 49.3 ± 21.2 years old. All 10 participants received a single dose of allogenic CL2020 (a total of 15 × 106 cells, 2.1-2.7 × 105 cells/kg of body weight), which is a Muse cell-based product produced from human mesenchymal stem cells, by an intravenous drip.

RESULTS

There were two reported severe adverse events, both of which were determined to have no causal relationship with Muse cell treatment. The change in the ISNCSCI motor score, the activity of daily living and quality of life scores showed statistically significant improvements compared to those data at the time of CL2020 administration.

CONCLUSION

In the present trial, no safety concerns were identified, and Muse cell product transplantation demonstrated good tolerability. Future clinical trials with appropriate study designs incorporating a control arm will clarify the definitive efficacy of single-dose allogenic Muse cell treatment with intravenous administration to treat SCI.

TRIAL REGISTRATION

jRCT, JRCT1080224764. Registered 03 July 2019, https://jrct.niph.go.jp/latest-detail/jRCT1080224764 .

The combined application of stem cells and three-dimensional bioprinting scaffolds for the repair of spinal cord injury

Spinal cord injury is considered one of the most difficult injuries to repair and has one of the worst prognoses for injuries to the nervous system. Following surgery, the poor regenerative capacity of nerve cells and the generation of new scars can make it very difficult for the impaired nervous system to restore its neural functionality. Traditional treatments can only alleviate secondary injuries but cannot fundamentally repair the spinal cord. Consequently, there is a critical need to develop new treatments to promote functional repair after spinal cord injury. Over recent years, there have been several developments in the use of stem cell therapy for the treatment of spinal cord injury. Alongside significant developments in the field of tissue engineering, three-dimensional bioprinting technology has become a hot research topic due to its ability to accurately print complex structures. This led to the loading of three-dimensional bioprinting scaffolds which provided precise cell localization. These three-dimensional bioprinting scaffolds could repair damaged neural circuits and had the potential to repair the damaged spinal cord. In this review, we discuss the mechanisms underlying simple stem cell therapy, the application of different types of stem cells for the treatment of spinal cord injury, and the different manufacturing methods for three-dimensional bioprinting scaffolds. In particular, we focus on the development of three-dimensional bioprinting scaffolds for the treatment of spinal cord injury.

The roles of neural stem cells in myelin regeneration and repair therapy after spinal cord injury

Spinal cord injury (SCI) is a complex tissue injury that results in a wide range of physical deficits, including permanent or progressive disabilities of sensory, motor and autonomic functions. To date, limitations in current clinical treatment options can leave SCI patients with lifelong disabilities. There is an urgent need to develop new therapies for reconstructing the damaged spinal cord neuron-glia network and restoring connectivity with the supraspinal pathways. Neural stem cells (NSCs) possess the ability to self-renew and differentiate into neurons and neuroglia, including oligodendrocytes, which are cells responsible for the formation and maintenance of the myelin sheath and the regeneration of demyelinated axons. For these properties, NSCs are considered to be a promising cell source for rebuilding damaged neural circuits and promoting myelin regeneration. Over the past decade, transplantation of NSCs has been extensively tested in a variety of preclinical models of SCI. This review aims to highlight the pathophysiology of SCI and promote the understanding of the role of NSCs in SCI repair therapy and the current advances in pathological mechanism, pre-clinical studies, as well as clinical trials of SCI via NSC transplantation therapeutic strategy. Understanding and mastering these frontier updates will pave the way for establishing novel therapeutic strategies to improve the quality of recovery from SCI.

Tauroursodeoxycholic Acid Inhibited Apoptosis and Oxidative Stress in H2O2-Induced BMSC Death via Modulating the Nrf-2 Signaling Pathway: the Therapeutic Implications in a Rat Model of Spinal Cord Injury

Spinal cord injury (SCI) is a prevalent and significant injury to the central nervous system, resulting in severe consequences. This injury is characterized by motor, sensory, and excretory dysfunctions below the affected spinal segment. Transplantation of bone marrow mesenchymal stem cells (BMSCs) has emerged as a potential treatment for SCI. However, the low survival as well as the differentiation rates of BMSCs within the spinal cord microenvironment significantly limit their therapeutic efficiency. Tauroursodeoxycholic acid (TUDCA), an active ingredient found in bear bile, has demonstrated its neuroprotective, antioxidant, and antiapoptotic effects on SCI. Thus, the present study was aimed to study the possible benefits of combining TUDCA with BMSC transplantation using an animal model of SCI. The results showed that TUDCA significantly enhanced BMSC viability and reduced apoptosis (assessed by Annexin V-FITC, TUNEL, Bax, Bcl-2, and Caspase-3) as well as oxidative stress (assessed by ROS, GSH, SOD, and MDA) both in vitro and in vivo. Additionally, TUDCA accelerated tissue regeneration (assessed by HE, Nissl, MAP2, MBP, TUJ1, and GFAP) and improved functional recovery (assessed by BBB score) following BMSC transplantation in SCI. These effects were mediated via the Nrf-2 signaling pathway, as evidenced by the upregulation of Nrf-2, NQO-1, and HO-1 expression levels. Overall, these results indicate that TUDCA could serve as a valuable adjunct to BMSC transplantation therapy for SCI, potentially enhancing its therapeutic efficacy.

MSC-derived exosomes deliver ZBTB4 to mediate transcriptional repression of ITIH3 in astrocytes in spinal cord injury

BACKGROUND

BMSC-secreted exosomes (BMSC-Exos) have shown potential for promoting behavioral recovery following spinal cord injury (SCI). However, its role in blocking astrocyte activation remains unclear. Thus, this study aimed to determine whether BMSC-Exos impair the function of astrocytes following SCI in mice and to seek the mechanism.

METHODS

BMSC-Exos were collected by ultracentrifugation and identified. The SCI mice were developed by laminectomy combined with spinal cord shock, followed by BMSC-Exos or nerve growth factor (positive control) treatment. HE staining, Nissl staining, and TUNEL were conducted to analyze the pathological structural damage and neuronal damage in the mouse spinal cord. Bioinformatics was used to screen altered molecules under the BMSC-Exos treatment. Effects of BMSC-Exos and changes in ZBTB4 and ITIH3 expression on neuronal damage induced by activated astrocytes in the co-culture system were analyzed by CCK-8 and flow cytometry.

RESULTS

Nerve growth factor and BMSC-Exos promoted motor function recovery, alleviated nerve injury, and reduced apoptosis in mice with SCI. ZBTB4 was enriched in BMSC-Exos and lowly expressed in SCI. Downregulation of ZBTB4 diminished the therapeutic effects of BMSC-Exos against SCI. ITIH3 was a downstream target of ZBTB4. Neurotoxic activation of astrocytes induced neuronal injury, which was alleviated by BMSC-Exos. However, ZBTB4 knockdown overturned the effects of BMSC-Exos in vitro and combined ITIH3 knockdown alleviated the accentuating effects of ZBTB4 knockdown on neuronal injury.

CONCLUSION

BMSC-Exos protected against astrocyte-induced neuronal injury by delivering ZBTB4 to repress ITIH3, ultimately improving motor function in mice with SCI.

Advances in natural and synthetic macromolecules with stem cells and extracellular vesicles for orthopedic disease treatment

Serious orthopedic disorders resulting from myriad diseases and impairments continue to pose a considerable challenge to contemporary clinical care. Owing to its limited regenerative capacity, achieving complete bone tissue regeneration and complete functional restoration has proven challenging with existing treatments. By virtue of cellular regenerative and paracrine pathways, stem cells are extensively utilized in the restoration and regeneration of bone tissue; however, low survival and retention after transplantation severely limit their therapeutic effect. Meanwhile, biomolecule materials provide a delivery platform that improves stem cell survival, increases retention, and enhances therapeutic efficacy. In this review, we present the basic concepts of stem cells and extracellular vesicles from different sources, emphasizing the importance of using appropriate expansion methods and modification strategies. We then review different types of biomolecule materials, focusing on their design strategies. Moreover, we summarize several forms of biomaterial preparation and application strategies as well as current research on biomacromolecule materials loaded with stem cells and extracellular vesicles. Finally, we present the challenges currently impeding their clinical application for the treatment of orthopedic diseases. The article aims to provide researchers with new insights for subsequent investigations.

Photobiomodulation therapy enhances neural differentiation of dental pulp stem cells via ERK1/2 signaling pathway

Photobiomodulation therapy (PBMT) is the application of a low-level laser device to generate physiological changes and provide therapeutic effects. Till now, the effects of PBMT on the neural differentiation of mesenchymal stem cells have been rarely reported. Herein, the potential effect and mechanism of PBMT on the neural differentiation of dental pulp stem cells (DPSCs) were preliminarily investigated in our research. The optimal dose of 3.75 J/cm2 was first screened for use in the following neural-inducing studies. Then, DPSCs were cultured in neural induction medium and treated with laser irradiation for 7 days. From the results of morphology and immunofluorescence, we found that irradiation promoted the formation of neural stem cell-like spheroids derived from DPSCs and enhanced potential neural differentiation. Furthermore, neural differentiation gene expressions of Nestin, microtubule-associated protein-2, and neural cell adhesion molecule were increased after PBMT irradiation. The protein expressions of class III β-tubulin and neurogenic differentiation factor 1 were also improved. Meanwhile, the involvement of extracellular signal-regulated kinase (ERK1/2) was investigated by western blot. Our study showed that the neural differentiation of DPSCs was promoted by PBMT, and the underlying mechanism in this process was associated with activating the ERK1/2 signaling pathway.

Current Advances in Mesenchymal Stem Cell Therapies Applied to Wounds and Skin, Eye, and Neuromuscular Diseases in Companion Animals

Mesenchymal stem cells (MSCs) are considered a very promising alternative tool in cell therapies and regenerative medicine due to their ease of obtaining from various tissues and their ability to differentiate into different cell types. This manuscript provides a review of current knowledge on the use of MSC-based therapies as an alternative for certain common pathologies in dogs and cats where conventional treatments are ineffective. The aim of this review is to assist clinical veterinarians in making decisions about the suitability of each protocol from a clinical perspective, rather than focusing solely on research. MSC-based therapies have shown promising results in certain pathologies, such as spinal cord injuries, wounds, and skin and eye diseases. However, the effectiveness of these cell therapies can be influenced by a wide array of factors, leading to varying outcomes. Future research will focus on designing protocols and methodologies that allow more precise and effective MSC treatments for each case.

Stepwise combined cell transplantation using mesenchymal stem cells and induced pluripotent stem cell-derived motor neuron progenitor cells in spinal cord injury

BACKGROUND

Spinal cord injury (SCI) is an intractable neurological disease in which functions cannot be permanently restored due to nerve damage. Stem cell therapy is a promising strategy for neuroregeneration after SCI. However, experimental evidence of its therapeutic effect in SCI is lacking. This study aimed to investigate the efficacy of transplanted cells using stepwise combined cell therapy with human mesenchymal stem cells (hMSC) and induced pluripotent stem cell (iPSC)-derived motor neuron progenitor cells (iMNP) in a rat model of SCI.

METHODS

A contusive SCI model was developed in Sprague-Dawley rats using multicenter animal spinal cord injury study (MASCIS) impactor. Three protocols were designed and conducted as follows: (Subtopic 1) chronic SCI + iMNP, (Subtopic 2) acute SCI + multiple hMSC injections, and (Main topic) chronic SCI + stepwise combined cell therapy using multiple preemptive hMSC and iMNP. Neurite outgrowth was induced by coculturing hMSC and iPSC-derived motor neuron (iMN) on both two-dimensional (2D) and three-dimensional (3D) spheroid platforms during mature iMN differentiation in vitro.

RESULTS

Stepwise combined cell therapy promoted mature motor neuron differentiation and axonal regeneration at the lesional site. In addition, stepwise combined cell therapy improved behavioral recovery and was more effective than single cell therapy alone. In vitro results showed that hMSC and iMN act synergistically and play a critical role in the induction of neurite outgrowth during iMN differentiation and maturation.

CONCLUSIONS

Our findings show that stepwise combined cell therapy can induce alterations in the microenvironment for effective cell therapy in SCI. The in vitro results suggest that co-culturing hMSC and iMN can synergistically promote induction of MN neurite outgrowth.

The beneficial effect of α-lipoic acid on spinal cord injury repair in rats is mediated through inhibition of oxidative stress: A transcriptomic analysis

BACKGROUND

Oxidative stress is a crucial factor contributing to the occurrence and development of secondary damage in spinal cord injuries (SCI), ultimately impacting the recovery process. α-lipoic acid (ALA) exhibits potent antioxidant properties, effectively reducing secondary damage and providing neuroprotective benefits. However, the precise mechanism by which ALA plays its antioxidant role remains unknown.

METHODS

We established a model of moderate spinal cord contusion in rats. Experimental rats were randomly divided into 3 distinct groups: the sham group, the model control group (SCI_Veh), and the ALA treatment group (SCI_ALA). The sham group rats were exposed only to the SC without contusion injury. Rats belonging to SCI_Veh group were not administered any treatment after SCI. Rats of SCI_ALA group were intraperitoneally injected with the corresponding volume of ALA according to body weight for three consecutive days after the surgery. Subsequently, three days after SCI, spinal cord samples were obtained from three groups of rats: the sham group, model control group, and administration group. Thereafter, total RNA was extracted from the samples and the expression of three sets of differential genes was analyzed by transcriptome sequencing technology. Real-time PCR was used to verify the sequencing results. The impact of ALA on oxidative stress in rats following SCI was assessed by measuring their total antioxidant capacity and hydrogen peroxide (H2O2) content. The effects of ALA on rat recovery following SCI was investigated through Beattie and Bresnahan (BBB) score and footprint analysis.

RESULTS

The findings from the transcriptome sequencing analysis revealed that the model control group had 2975 genes with altered expression levels when compared to the ALA treatment group. Among these genes, 1583 were found to be upregulated while 1392 were down-regulated. Gene ontology (GO) displayed significant enrichment in terms of functionality, specifically in oxidative phosphorylation, oxidoreductase activity, and signaling receptor activity. The Kyoto encyclopedia of genes and genomes (KEGG) pathway was enriched in oxidative phosphorylation, glutathione metabolism and cell cycle. ALA was found to have multiple benefits for rats after SCI, including increasing their antioxidant capacity and reducing H2O2 levels. Additionally, it was effective in improving motor function (such as 7 days after SCI, the BBB score for SCI_ALA was 8.400 ± 0.937 compared to 7.050 ± 1.141 for SCI_Veh) and promoting histological recovery after SCI (The results of HE demonstrated that the percentage of damage area in was 44.002 ± 6.680 in the SCI_ALA and 57.215 ± 3.964 in the SCI_Veh at the center of injury.). The sequence data from this study has been deposited into Sequence Read Archive (https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE242507).

CONCLUSION

Overall, the findings of this study confirmed the beneficial effects of ALA on recovery in SCI rats through transcriptome sequencing, behavioral, as well histology analyses.

[Jisuikang formula promotes spinal cord injury repair in rats by activating the YAP/PKM2 signaling axis in astrocytes]

OBJECTIVE

To investigate the effect of Jisuikang formula-medicated serum for promoting spinal cord injury (SCI) repair in rats and explore the possible mechanism.

METHODS

Thirty adult SD rats were randomized into sham-operated group, SCI (induced using a modified Allen method) model group, and Jisuikang formula-medicated serum treatment group. After the operations, the rats were treated with normal saline or Jisuikang by gavage on a daily basis for 14 days, and the changes in hindlimb motor function of the rats was assessed with Basso-Beattie-Bresnahan (BBB) scores and inclined-plate test. The injured spinal cord tissues were sampled from the SCI rat models for single-cell RNA sequencing, and bioinformatics analysis was performed to identify the target genes of Jisuikang, spinal cord injury and glycolysis. In the cell experiment, cultured astrocytes from neonatal SD rat cortex were treated with SOX2 alone or in combination with Jisuikang-medicated serum for 21 days, and the protein expressions of PKM2, p-PKM2 and YAP and colocalization of PKM2 and YAP in the cells were analyzed with Western blotting and immunofluorescence staining, respectively.

RESULTS

The SCI rats with Jisuikang treatment showed significantly improved BBB scores and performance in inclined-plate test. At the injury site, high PKM2 expression was detected in various cell types. Bioinformatic analysis identified the HIPPO-YAP signaling pathway as the target pathway of Jisuikang. In cultured astrocytes, SOX2 combined with the mediated serum, as compared with SOX2 alone, significantly increased PKM2, p-PKM2 and YAP expressions and entry of phosphorylated PKM2 into the nucleus, and promoted PKM2 and YAP co-localization in the cells.

CONCLUSION

Jisuikang formula accelerates SCI repair in rats possibly by promoting aerobic glycolysis of the astrocytes via activating the PKM2/YAP axis to induce reprogramming of the astrocytes into neurons.

Advancing Spinal Cord Injury Bioimaging and Repair with Multifunctional Gold Nanodots Tracking

High levels of reactive oxygen species (ROS) are known to play a critical role in the secondary cascade of spinal cord injury (SCI). The scavenging of ROS has emerged as a promising approach for alleviating acute SCI. Moreover, identifying the precise location of the SCI site remains challenging. Enhancing the visualization of the spinal cord and improving the ability to distinguish the lesion site are crucial for accurate and safe treatment. Therefore, there is an urgent clinical need to develop a biomaterial that integrates diagnosis and treatment for SCI. Herein, ultra-small-sized gold nanodots (AuNDs) were designed for dual-mode imaging-guided precision treatment of SCI. The designed AuNDs demonstrate two important functions. First, they effectively scavenge ROS, inhibit oxidative stress, reduce the infiltration of inflammatory cells, and prevent apoptosis. This leads to a significant improvement in SCI repair and promotes a functional recovery after injury. Second, leveraging their excellent dual-mode imaging capabilities, the AuNDs enable rapid and accurate identification of SCI sites. The high contrast observed between the injured and adjacent uninjured areas highlights the tremendous potential of AuNDs for SCI detection. Overall, by integrating ROS scavenging and dual-mode imaging in a single biomaterial, our work on functionalized AuNDs provides a promising strategy for the clinical diagnosis and treatment of SCI.

Reprogramming of astrocytes to neuronal-like cells in spinal cord injury: a systematic review

STUDY DESIGN

A Systematic Review OBJECTIVES: To determine the therapeutic efficacy of in vivo reprogramming of astrocytes into neuronal-like cells in animal models of spinal cord injury (SCI).

METHODS

PRISMA 2020 guidelines were utilized, and search engines Medline, Web of Science, Scopus, and Embase until June 2023 were used. Studies that examined the effects of converting astrocytes into neuron-like cells with any vector in all animal models were included, while conversion from other cells except for spinal astrocytes, chemical mechanisms to provide SCI models, brain injury population, and conversion without in-vivo experience were excluded. The risk of bias was calculated independently.

RESULTS

5302 manuscripts were initially identified and after eligibility assessment, 43 studies were included for full-text analysis. After final analysis, 13 manuscripts were included. All were graded as high-quality assessments. The transduction factors Sox2, Oct4, Klf4, fibroblast growth factor 4 (Fgf4) antibody, neurogenic differentiation 1 (Neurod1), zinc finger protein 521 (Zfp521), ginsenoside Rg1, and small molecules (LDN193189, CHIR99021, and DAPT) could effectively reprogramme astrocytes into neuron-like cells. The process was enhanced by p21-p53, or Notch signaling knockout, valproic acid, or chondroitin sulfate proteoglycan inhibitors. The type of mature neurons was both excitatory and inhibitory.

CONCLUSION

Astrocyte reprogramming to neuronal-like cells in an animal model after SCI appears promising. The molecular and functional improvements after astrocyte reprogramming were demonstrated in vivo, and further investigation is required in this field.

Transplantation of MiR-28-5p-Modified BMSCs Promotes Functional Recovery After Spinal Cord Injury

Traumatic spinal cord injury (TSCI) is a prevalent central nervous system condition that imposes a significant burden on both families and society, affecting more than 2 million people worldwide. Recently, there has been increasing interest in bone marrow mesenchymal stem cell (BMSC) transplantation as a promising treatment for spinal cord injury (SCI) due to their accessibility and low immunogenicity. However, the mere transplantation of BMSCs has limited capacity to directly participate in the repair of host spinal cord nerve function. MiR-28-5p, identified as a key differentially expressed miRNA in spinal cord ischemia-reperfusion injury, exhibits differential expression and regulation in various neurological diseases. Nevertheless, its involvement in this process and its specific regulatory mechanisms in SCI remain unclear. Therefore, this study aimed to investigate the potential mechanisms through which miR-28-5p promotes the neuronal differentiation of BMSCs both in vivo and in vitro. Our results indicate that miR-28-5p may directly target Notch1, thereby facilitating the neuronal differentiation of BMSCs in vitro. Furthermore, the transplantation of lentivirus-mediated miR-28-5p-overexpressed BMSCs into SCI rats effectively improved footprint tests and Basso, Beattie, and Bresnahan (BBB) scores, ameliorated histological morphology (hematoxylin-eosin [HE] and Nissl staining), promoted axonal regeneration (MAP2 and growth-associated protein 43 [GAP43]), and facilitated axonal remyelination (myelin basic protein [MBP]). These findings may suggest that miR-28-5p-modified BMSCs could serve as a therapeutic target to enhance the behavioral and neurological recovery of SCI rats.

Local Spinal Cord Injury Treatment Using a Dental Pulp Stem Cell Encapsulated H2S Releasing Multifunctional Injectable Hydrogel

Spinal cord injury (SCI) commonly induces nerve damage and nerve cell degeneration. In this work, a novel dental pulp stem cells (DPSCs) encapsulated thermoresponsive injectable hydrogel with sustained hydrogen sulfide (H2S) delivery is demonstrated for SCI repair. For controlled and sustained H2S gas therapy, a clinically tested H2S donor (JK) loaded octysilane functionalized mesoporous silica nanoparticles (OMSNs) are incorporated into the thermosensitive hydrogel made from Pluronic F127 (PF-127). The JK-loaded functionalized MSNs (OMSF@JK) promote preferential M2-like polarization of macrophages and neuronal differentiation of DPSCs in vitro. OMSF@JK incorporated PF-127 injectable hydrogel (PF-OMSF@JK) has a soft consistency similar to that of the human spinal cord and thus, shows a high cytocompatibility with DPSCs. The cross-sectional micromorphology of the hydrogel shows a continuous porous structure. Last, the PF-OMSF@JK composite hydrogel considerably improves the in vivo SCI regeneration in Sprague-Dawley rats through a reduction in inflammation and neuronal differentiation of the incorporated stem cells as confirmed using western blotting and immunohistochemistry. The highly encouraging in vivo results prove that this novel design on hydrogel is a promising therapy for SCI regeneration with the potential for clinical translation.

Rehabilitation training enhanced the therapeutic effect of calycosin on neurological function recovery of rats following spinal cord injury

BACKGROUND

Calycosin (CA), a flavonoids component, has demonstrated potential neuroprotection effects by inhibiting oxidative stress in spinal cord injury (SCI) models. This study aims to investigate the impact of combined rehabilitation training (RT) and calycosin therapy on neurological function following SCI, primarily by assessing changes in motor function recovery, neuronal survival, neuronal oxidative stress levels, and neural proliferation, in order to provide novel insights for the treatment of SCI.

MATERIALS AND METHODS

The SCI model was constructed by compressing the spinal cord using vascular clamps. Calycosin was injected intraperitoneally into the SCI model rats, and a group of 5 rats underwent RT. The motor function of rats after SCI was evaluated using the Basso Beattle Bresnaha (BBB) score and the inclined plate test. Histopathological changes were evaluated by NeuN immunohistochemistry, HE and Nissl staining. Apoptosis was detected by TUNEL staining. The antioxidant effect of combined treatment was assessed by measuring changes in oxidative stress markers after SCI. Western blot analysis was conducted to examine changes in Hsp90-Akt/ASK1-p38 pathway-related proteins. Finally, cell proliferation was detected by BrdU and Ki67 assays.

RESULTS

RT significantly improved the BBB score and angle of incline promoted by calycosin, resulting in enhanced motor function recovery in rats with SCI. Combining rehabilitation training with calycosin has a positive effect on morphological recovery. Similarly, combined RT enhanced the Nissl and NeuN staining signals of spinal cord neurons increased by calycosin, thereby increasing the number of neurons. TUNEL staining results indicated that calycosin treatment reduced the apoptosis signal in SCI, and the addition of RT further reduced the apoptosis. Moreover, RT combined with calycosin reduced oxidative stress by increasing SOD and GSH levels, while decreasing MDA, NO, ROS, and LDH expressions compared to the calycosin alone. RT slightly enhanced the effect of calycosin in activating Hsp90 and Akt and inhibiting the activation of ASK1 and p38, leading to enhanced inhibition of oxidative stress by calycosin. Additionally, the proliferation indexes (Ki67 and BrdU) assays showed that calycosin treatment alone increased both, whereas the combination treatment further promoted cell proliferation.

CONCLUSION

Our research findings demonstrate that rehabilitation training enhances the ability of calycosin to reduce oxidative stress, resulting in a decrease in neuronal apoptosis and an increase in proliferation, ultimately promoting neuronal survival.

Transcriptome profile analysis in spinal cord injury rats with transplantation of menstrual blood-derived stem cells

Introduction

Menstrual blood-derived stem cells (MenSCs) are vital in treating many degenerative and traumatic disorders. However, the underlying molecular mechanisms remain obscure in MenSCs-treating spinal cord injury (SCI) rats.

Methods

MenSCs were adopted into the injured sites of rat spinal cords at day 7 post surgery and the tissues were harvested for total RNA sequencing analysis at day 21 after surgery to investigate the expression patterns of RNAs. The differentially expressed genes (DEGs) were analyzed with volcano and heatmap plot. DEGs were sequentially analyzed by weighted gene co-expression network, functional enrichment, and competitive endogenous RNAs (ceRNA) network analysis. Next, expression of selected miRNAs, lncRNAs, circRNAs and mRNAs were validated by quantitative real-time polymerase chain reaction (qRT-PCR). Bioinformatics packages and extra databases were enrolled to scoop the genes functions and their interaction relationships.

Results

A total of 89 lncRNAs, 65 circRNAs, 120 miRNAs and 422 mRNAs were significantly upregulated and 65 lncRNAs, 72 circRNAs, 74 miRNAs, and 190 mRNAs were significantly downregulated in the MenSCs treated rats compared to SCI ones. Current investigation revealed that MenSCs treatment improve the recovery of the injured rats and the most significantly involved pathways in SCI regeneration were cell adhesion molecules, nature killer cell mediated cytotoxicity, primary immunodeficiency, chemokine signaling pathway, T cell receptor signaling pathway and B cell receptor signaling pathway. Moreover, the lncRNA-miRNA-mRNA and circRNA-miRNA-mRNA ceRNA network of SCI was constructed. Finally, the protein-protein interaction (PPI) network was constructed using the top 100 DE mRNAs. The constructed PPI network included 47 nodes and 70 edges.

Discussion

In summary, the above results revealed the expression profile and potential functions of differentially expressed (DE) RNAs in the injured spinal cords of rats in the MenSCs-treated and SCI groups, and this study may provide new clues to understand the mechanisms of MenSCs in treating SCI.

Serum response factor promoting axonal regeneration by activating the Ras-Raf-Cofilin signaling pathway after the spinal cord injury

INTRODUCTION

Serum response factor (SRF) is important in muscle development, tissue repair, and neuronal regulation.

OBJECTIVES

This research aims to thoroughly examine the effects of SRF on spinal cord injury (SCI) and its ability to significantly impact the recovery and regeneration of neuronal axons.

METHODS

The researchers created rat models of SCI and scratch injury to primary spinal cord neurons to observe the expression of relevant factors after neuronal injury.

RESULTS

We found that the SRF, Ras, Raf, and cofilin levels increased after injury and gradually returned to normal levels. Afterward, researchers gave rats with SCI an SRF inhibitor (CCG1423) and studied the effects with nuclear magnetic resonance and transmission electron microscopy. The SRF inhibitor rodents had worse spinal cord recovery and axon regrowth than the control group. And the apoptosis of primary neurons after scratch injury was significantly higher in the SRF inhibitor group. Additionally, the researchers utilized lentiviral transfection to modify the SRF expression in neurons. SRF overexpression increased neuron migration while silencing SRF decreased it. Finally, Western blotting and RT-PCR were conducted to examine the expression changes of related factors upon altering SRF expression. The results revealed SRF overexpression increased Ras, Raf, and cofilin expression. Silencing SRF decreased Ras, Raf, and Cofilin expression.

CONCLUSION

Based on our research, the SRF promotes axonal regeneration by activating the "Ras-Raf-Cofilin" signaling pathway.

Effects of ADSC-Derived Exosome LRRC75A-AS1 on Anti-inflammatory Function After SCI

Spinal cord injury (SCI) is a highly debilitating disorder of the central nervous system that can severely impact an affected patient's quality of life. This study aimed to examine how adipose-derived mesenchymal stem cell exosomes (ADSC-exos) can be used to treat spinal cord injury. We analysed differentially expressed mRNAs in SCI using bioinformatics data, gene expression profiles in inflammatory cell models, RT-qPCR and WB. Apoptosis was detected with flow cytometry. Starbase provides the control mechanism for FDFT1. Target interactions were detected with dual-luciferase reporter and RIP assays. Exosomes were isolated from adipose tissue-derived mesenchymal stem cells and subsequently characterized with western blot analysis, transmission electron microscopy and nanoparticle tracking analysis. By analysing the GSE102964 database, we found that FDFT1 was significantly downregulated as SCI progressed. Overexpression of FDFT1 can significantly reverse the inflammatory response and apoptosis of BV2 cells induced by hemin. Mechanically, ADSC-exos can affect the expression of FDFT1 through the ceRNA mechanism mediated by LRRC75A-AS1 and in an RBP-dependent manner mediated by IGF2BP2. The overexpression of LRRC75A-AS1 significantly enhances BV2 apoptosis and can be reversed by FDFT1 knockdown. ADSC-exos LRRC75A-AS1 inhibits inflammation and reduces SCI by increasing the expression and stability of FDFT1 mRNA in a ceRNA and RBP-dependent manner.

Initial IL-10 production dominates the therapy of mesenchymal stem cell scaffold in spinal cord injury

Rationale: Spinal cord injury (SCI) is an acute damage to the central nervous system that results in severe morbidity and permanent disability. Locally implanted scaffold systems with immobilized mesenchymal stem cells (MSCs) have been widely proven to promote locomotor function recovery in SCI rats; however, the underlying mechanism remains elusive. Methods and Results: In this study, we constructed a hyaluronic acid scaffold system (HA-MSC) to accelerate the adhesive growth of human MSCs and prolong their survival time in SCI rat lesions. MSCs regulate local immune responses by upregulating the expression of anti-inflammatory cytokines. Interestingly, the dramatically increased, but transient expression of interleukin 10 (IL-10) is found to be secreted by MSCs in the first week. Blocking the function of the initially produced IL-10 by the antibody completely abolished the neurological and behavioral recovery of SCI rats, indicating a core role of IL-10 in SCI therapy with HA-MSC implantation. Transcriptome analyses indicated that IL-10 selectively promotes the migration and cytokine secretion-associated programs of MSCs, which in turn helps MSCs exert their anti-inflammatory therapeutic effects. Conclusion: Our findings highlight a novel role of IL-10 in regulating MSC migration and cytokine secretion-associated programs, and determine the vital role of IL-10 in the domination of MSC treatment for spinal cord repair.

Application of Injectable Hydrogels as Delivery Systems in Spinal Cord Injury

Spinal cord injury (SCI) is a severe neurological injury caused by traffic accidents, trauma, or falls, which leads to significant loss of sensory, motor, and autonomous functions and seriously affects the patient's life quality. Although considerable progress has been made in mitigating secondary injury and promoting the regeneration/repair of SCI, the therapeutic effects need to be improved due to drug availability. Given their good biocompatibility, biodegradability, and low immunogenicity, injectable hydrogels can be used as delivery systems to achieve controlled release of drugs and other substances (cells and proteins, etc.), offering new hope for SCI repair. In this article, we summarized the types of injectable hydrogels, analyzed their application as delivery systems in SCI, and further discussed the mechanisms of hydrogels in the treatment of SCI, such as anti-inflammatory, antioxidant, anti-apoptosis, and pro-neurogenesis. Moreover, we highlighted the potential benefits of hydrogels in the treatment of SCI in combination with therapies, including the recent advances and achievements of these promising tools. Our review may offer new strategies for the development of SCI treatments based on injectable hydrogels as delivery systems.

Stem cells in central nervous system diseases: Promising therapeutic strategies

Central nervous system (CNS) diseases are a leading cause of death and disability. Due to CNS neurons have no self-renewal and regenerative ability as they mature, their loss after injury or disease is irreversible and often leads to functional impairments. Unfortunately, therapeutic options for CNS diseases are still limited, and effective treatments for these notorious diseases are warranted to be explored. At present, stem cell therapy has emerged as a potential therapeutic strategy for improving the prognosis of CNS diseases. Accumulating preclinical and clinical evidences have demonstrated that multiple molecular mechanisms, such as cell replacement, immunoregulation and neurotrophic effect, underlie the use of stem cell therapy for CNS diseases. However, several issues have yet to be addressed to support its clinical application. Thus, this review article aims to summarize the role and underlying mechanisms of stem cell therapy in treating CNS diseases. And it is worthy of further evaluation for the potential therapeutic applications of stem cell treatment in CNS disease.

Small extracellular vesicles derived from umbilical cord mesenchymal stem cells repair blood-spinal cord barrier disruption after spinal cord injury through down-regulation of Endothelin-1 in rats

Spinal cord injury could cause irreversible neurological dysfunction by destroying the blood-spinal cord barrier (BSCB) and allowing blood cells like neutrophils and macrophages to infiltrate the spinal cord. Small extracellular vesicles (sEVs) derived from mesenchymal stem cells (MSCs) found in the human umbilical cord have emerged as a potential therapeutic alternative to cell-based treatments. This study aimed to investigate the mechanism underlying the alterations in the BSCB permeability by human umbilical cord MSC-derived sEVs (hUC-MSCs-sEVs) after SCI. First, we used hUC-MSCs-sEVs to treat SCI rat models, demonstrating their ability to inhibit BSCB permeability damage, improve neurological repair, and reduce SCI-induced upregulation of prepro-endothelin-1 (prepro-ET-1) mRNA and endothelin-1 (ET-1) peptide expression. Subsequently, we confirmed that hUC-MSCs-sEVs could alleviate cell junction destruction and downregulate MMP-2 and MMP-9 expression after SCI, contributing to BSCB repair through ET-1 inhibition. Finally, we established an in vitro model of BSCB using human brain microvascular endothelial cells and verified that hUC-MSCs-sEVs could increase the expression of junction proteins in endothelial cells after oxygen-glucose deprivation by ET-1 downregulation. This study indicates that hUC-MSCs-sEVs could help maintain BSCB's structural integrity and promote functional recovery by suppressing ET-1 expression.

Advancing Spinal Cord Injury Treatment through Stem Cell Therapy: A Comprehensive Review of Cell Types, Challenges, and Emerging Technologies in Regenerative Medicine

Spinal cord injuries (SCIs) can lead to significant neurological deficits and lifelong disability, with far-reaching physical, psychological, and economic consequences for affected individuals and their families. Current treatments for SCIs are limited in their ability to restore function, and there is a pressing need for innovative therapeutic approaches. Stem cell therapy has emerged as a promising strategy to promote the regeneration and repair of damaged neural tissue following SCIs. This review article comprehensively discusses the potential of different stem cell types, such as embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs), mesenchymal stem cells (MSCs), and neural stem/progenitor cells (NSPCs), in SCI treatment. We provide an in-depth analysis of the unique advantages and challenges associated with each stem cell type, as well as the latest advancements in the field. Furthermore, we address the critical challenges faced in stem cell therapy for SCIs, including safety concerns, ethical considerations, standardization of protocols, optimization of transplantation parameters, and the development of effective outcome measures. We also discuss the integration of novel technologies such as gene editing, biomaterials, and tissue engineering to enhance the therapeutic potential of stem cells. The article concludes by emphasizing the importance of collaborative efforts among various stakeholders in the scientific community, including researchers, clinicians, bioengineers, industry partners, and patients, to overcome these challenges and realize the full potential of stem cell therapy for SCI patients. By fostering such collaborations and advancing our understanding of stem cell biology and regenerative medicine, we can pave the way for the development of groundbreaking therapies that improve the lives of those affected by SCIs.

The circ_006573/miR-376b-3p Axis Advances Spinal Cord Functional Recovery after Injury by Modulating Vascular Regeneration

Abnormal expression of non-coding RNAs after spinal cord injury (SCI) is associated with pathophysiological outcomes. We bioinformatically predicted a circRNA-miRNA-mRNA axis in SCI. A total of 4690 mRNAs, 17 miRNAs, and 3928 circRNAs were differentially expressed, with co-expressed RNAs predicted to regulate pathways related to wound healing. Among the most highly differentially expressed circRNAs, circ_006573, but not circ_016395, weakened the viability and migration of rat aortic endothelial cells, and its biological effects were rescued with miR-376b-3p mimics. Furthermore, circ_006573 overexpression induced changes in Cebpb, IL-18, and Plscr1 expression that were reversed by miR-376b-3p. In a rat model, circ_006573 shRNA administration improved the pathological manifestations of SCI and ameliorated motor function. Moreover, the expression of CD31, CD34, and VEGF-A in spinal cord tissues was significantly elevated after circ_006573 shRNA treatment, indicating that circ_006573 may be involved in vascular regeneration and functional recovery after SCI. Thus, the circ_006573-miR-376b-3p axis offers a foundation for understanding pathophysiological mechanisms and predicting strategies for treating SCI.

Thermos-responsive hydrogel system encapsulated engineered exosomes attenuate inflammation and oxidative damage in acute spinal cord injury

Introduction: Spinal cord injury (SCI) is a serious and disabling condition, and the effectiveness of conventional treatment is limited, such as supportive treatment and emergency surgery. Exosomes derived from umbilical cord mesenchymal stem cells (UCMSC-Exos) have potential therapeutic effects on SCI but are limited by delivery efficiency. Our study aimed to further investigate the therapeutic effects of miR-138-modified UCMSC-exosomes (Exos-138) following SCI. Methods: We developed an injectable triblock polymer of polyglycolic acid copolymer and polyethylene glycol (PLGA-PEG-PLGA)-loaded temperature-sensitive hydrogel of miR-138-modified stem cell exosomes and characterised its biocompatibility in vitro. In Sprague-Dawley rats with SCI, the hydrogel was injected into the injury site, behavioural scores were measured, and pathological analysis was conducted postoperatively to assess neurological recovery. Results: In vitro, our data demonstrated that miR-138-5p-modified UCMSC-Exos can reduce inflammation levels in BV-2 cells through the NLRP3-caspase1 signalling pathway and reduce neuronal apoptosis by downregulating intracellular reactive oxygen species levels through the Nrf2-keap1 signalling cascade. The results of in vivo experiments showed that the P-Exos-138 hydrogel promoted neurological recovery in rats with SCI. Discussion: Our study explored a novel exosome delivery system that can be a potential therapeutic strategy for SCI. Our study, currently, has theoretical value; however, it can serve as a basis for further investigations on the treatment approaches at various stages of SCI development in inflammation-dependent injury of the central nervous system.

Human retinal secretome: A cross-link between mesenchymal and retinal cells

In recent years, mesenchymal stem cells (MSC) have been considered the most effective source for regenerative medicine, especially due to released soluble paracrine bioactive components and extracellular vesicles. These factors, collectively called the secretome, play crucial roles in immunomodulation and in improving survival and regeneration capabilities of injured tissue. Recently, there has been a growing interest in the secretome released by retinal cytotypes, especially retinal pigment epithelium and Müller glia cells. The latter trophic factors represent the key to preserving morphofunctional integrity of the retina, regulating biological pathways involved in survival, function and responding to injury. Furthermore, these factors can play a pivotal role in onset and progression of retinal diseases after damage of cell secretory function. In this review, we delineated the importance of cross-talk between MSCs and retinal cells, focusing on common/induced secreted factors, during experimental therapy for retinal diseases. The cross-link between the MSC and retinal cell secretomes suggests that the MSC secretome can modulate the retinal cell secretome and vice versa. For example, the MSC secretome can protect retinal cells from degeneration by reducing oxidative stress, autophagy and programmed cell death. Conversely, the retinal cell secretome can influence the MSC secretome by inducing changes in MSC gene expression and phenotype.

Cell therapies for spinal cord injury: a review of the clinical trials and cell-type therapeutic potential

Spinal cord injury (SCI) is an as yet untreatable neuropathology that causes severe dysfunction and disability. Cell-based therapies hold neuroregenerative and neuroprotective potential, but, although being studied in SCI patients for more than two decades, long-term efficacy and safety remain unproven, and which cell types result in higher neurological and functional recovery remains under debate. In a comprehensive scoping review of 142 reports and registries of SCI cell-based clinical trials, we addressed the current therapeutical trends and critically analysed the strengths and limitations of the studies. Schwann cells, olfactory ensheathing cells (OECs), macrophages and various types of stem cells have been tested, as well as combinations of these and other cells. A comparative analysis between the reported outcomes of each cell type was performed, according to gold-standard efficacy outcome measures like the ASIA impairment scale, motor and sensory scores. Most of the trials were in the early phases of clinical development (phase I/II), involved patients with complete chronic injuries of traumatic aetiology and did not display a randomized comparative control arm. Bone marrow stem cells and OECs were the most commonly tested cells, while open surgery and injection were the main methods of delivering cells into the spinal cord or submeningeal spaces. Transplantation of support cells, such as OECs and Schwann cells, resulted in the highest ASIA Impairment Scale (AIS) grade conversion rates (improvements in ∼40% of transplanted patients), which surpassed the spontaneous improvement rate expected for complete chronic SCI patients within 1 year post-injury (5-20%). Some stem cells, such as peripheral blood-isolated and neural stem cells, offer potential for improving patient recovery. Complementary treatments, particularly post-transplantation rehabilitation regimes, may contribute highly to neurological and functional recovery. However, unbiased comparisons between the tested therapies are difficult to draw, given the great heterogeneity of the design and outcome measures used in the SCI cell-based clinical trials and how these are reported. It is therefore crucial to standardize these trials when aiming for higher value clinical evidence-based conclusions.

The Role of Mesenchymal Stromal Cells and Their Products in the Treatment of Injured Spinal Cords

Spinal cord injury (SCI) is a destructive condition that results in lasting neurological damage resulting in disruption of the connection between the central nervous system and the rest of the body. Currently, there are several approaches in the treatment of a damaged spinal cord; however, none of the methods allow the patient to return to the original full-featured state of life before the injury. Cell transplantation therapies show great potential in the treatment of damaged spinal cords. The most examined type of cells used in SCI research are mesenchymal stromal cells (MSCs). These cells are at the center of interest of scientists because of their unique properties. MSCs regenerate the injured tissue in two ways: (i) they are able to differentiate into some types of cells and so can replace the cells of injured tissue and (ii) they regenerate tissue through their powerful known paracrine effect. This review presents information about SCI and the treatments usually used, aiming at cell therapy using MSCs and their products, among which active biomolecules and extracellular vesicles predominate.

Proteomic profile of Trichinella spiralis infected mice with acute spinal cord injury: A 4D label-free quantitative analysis

Spinal cord injury (SCI) can cause severe loss of locomotor and sensory activities, with no ideal treatment. Emerging reports suggest that the helminth therapy is highly effective in relieving numerous inflammatory diseases. Proteomic profiling is often used to elucidate the underlying mechanism behind SCI. Herein, we systematically compared the protein expression profiles of murine SCI spinal cord and Trichinella spiralis treated murine SCI spinal cord, using a 4D label-free technique known for its elevated sensitivity. Relative to the SCI mice, the T. spiralis-treated mice exhibited marked alterations in 91 proteins (31 up- and 60 down-regulated). Based on our Gene Ontology (GO) functional analysis, the differentially expressed proteins (DEPs) were primarily enriched in the processes of metabolism, biological regulation, cellular process, antioxidant activity, and other cell functions. In addition, according to the Clusters of Orthologous Groups of protein/EuKaryotic Orthologous Groups (COG/KOG) functional stratification, proteins involved in signaling transduction mechanisms belonged to the largest category. Over-expressed DEPs were also enriched in the "NADPH oxidase complex", "superoxide anion generation", "other types of O-glycan biosynthesis", and "HIF-1 signaling pathway". Furthermore, the protein-protein interaction (PPI) network identified the leading 10 hub proteins. In conclusion, we highlighted the dynamic proteomic profiling of T. spiralis-treated SCI mice. Our findings provide significant insight into the molecular mechanism behind T. spiralis regulation of SCI.

Applications of chitosan-based biomaterials: From preparation to spinal cord injury neuroprosthetic treatment

Spinal cord injury (SCI)-related disabilities are a serious problem in the modern society. Further, the treatment of SCI is highly challenging and is urgently required in clinical practice. Research on nerve tissue engineering is an emerging approach for improving the treatment outcomes of SCI. Chitosan (CS) is a cationic polysaccharide derived from natural biomaterials. Chitosan has been found to exhibit excellent biological properties, such as nontoxicity, biocompatibility, biodegradation, and antibacterial activity. Recently, chitosan-based biomaterials have attracted significant attention for SCI repair in nerve tissue engineering applications. These studies revealed that chitosan-based biomaterials have various functions and mechanisms to promote SCI repair, such as promoting neural cell growth, guiding nerve tissue regeneration, delivering nerve growth factors, and as a vector for gene therapy. Chitosan-based biomaterials have proven to have excellent potential for the treatment of SCI. This review aims to introduce the recent advances in chitosan-based biomaterials for SCI treatment and to highlight the prospects for further application.

Mesenchymal stem cells in the treatment of spinal cord injury: Mechanisms, current advances and future challenges

Spinal cord injury (SCI) has considerable impact on patient physical, mental, and financial health. Secondary SCI is associated with inflammation, vascular destruction, and subsequent permanent damage to the nervous system. Mesenchymal stem cells (MSCs) have anti-inflammatory properties, promoting vascular regeneration and the release neuro-nutrients, and are a promising strategy for the treatment of SCI. Preclinical studies have shown that MSCs promote sensory and motor function recovery in rats. In clinical trials, MSCs have been reported to improve the American Spinal Injury Association (ASIA) sensory and motor scores. However, the effectiveness of MSCs in treating patients with SCI remains controversial. MSCs promote tumorigenesis and ensuring the survival of MSCs in the hostile environment of SCI is challenging. In this article we examine the evidence on the pathophysiological changes occurring after SCI. We then review the underlying mechanisms of MSCs in the treatment of SCI and summarize the potential application of MSCs in clinical practice. Finally, we highlight the challenges surrounding the use of MSCs in the treatment of SCI and discuss future applications.

The involvement of EGR1 in neuron apoptosis in the in vitro model of spinal cord injury via BTG2 up-regulation

OBJECTIVE

EGR1 has been implicated in the progression of spinal cord injury (SCI). Nevertheless, its specific mechanism in SCI remains to be investigated. Hence, this study explored the potential mechanism of EGR1 in SCI by focusing on neuron apoptosis.

METHODS

H₂O₂ was utilized to treat rat neurons-dorsal spinal cord (RN-dsc) for the construction of an in vitro model of SCI. Afterwards, cell survival, apoptosis, and LDH leakage were detected to evaluate the injury degree of H₂O₂-treated RN-dsc. The expression of apoptosis-related proteins was also measured. Additionally, EGR1 was silenced and/or BTG2 was overexpressed in RN-dsc before H₂O₂ treatment to assess the impacts of EGR1 and BTG2 on H₂O₂-induced RN-dsc. Jasper online website was utilized to predict binding sites of EGR1 on BTG2, and dual-luciferase reporter gene and chromatin immunoprecipitation (ChIP) assays were utilized to verify the binding between EGR1 and BTG2.

RESULTS

H₂O₂ treatment suppressed survival and promoted apoptosis in RN-dsc, accompanied by upregulated LDH, Bax, and cleaved-caspase-3 and down-regulated Bcl-2. Moreover, EGR1 and BTG2 were up-regulated in H₂O₂-induced RN-dsc. Mechanistically, EGR1 was bound to the promoter of BTG2 to transcriptionally activate BTG2. EGR1 knockdown diminished apoptosis and LDH, Bax, and cleaved-caspase-3 levels while elevating survival and Bcl-2 levels in H₂O₂-induced RN-dsc. These effects of EGR1 knockdown were abrogated by further BTG2 overexpression.

DISCUSSION

Conclusively, EGR1 promotes H₂O₂-induced apoptosis in RN-dsc by activating BTG2 transcription.

An Electroconductive Hydrogel Scaffold with Injectability and Biodegradability to Manipulate Neural Stem Cells for Enhancing Spinal Cord Injury Repair

Spinal cord injury (SCI) generally leads to long-term functional deficits and is difficult to repair spontaneously. Many biological scaffold materials and stem cell treatment strategies have been explored, but very little research focused on the method of combining exogenous neural stem cells (NSCs) with a biodegradable conductive hydrogel scaffold. Here, a NSC loaded conductive hydrogel scaffold (named ICH/NSCs) was assembled by amino-modified gelatin (NH₂-Gelatin) and aniline tetramer grafted oxidized hyaluronic acid (AT-OHA). Desirably, the well-conducting ICH/NSCs can be simply injected into the target site of SCI for establishing a good electrical signal pathway of cells, and the proper degradation cycle facilitates new nerve growth. In vitro experiments indicated that the inherent electroactive microenvironment of the hydrogel could better manipulate the differentiation of NSCs into neurons and inhibit the formation of glial cells and scars. Collectively, the ICH/NSC scaffold has successfully stimulated the recovery of SCI and may provide a promising treatment strategy for SCI repair.

Hydrogen Promotes the Effectiveness of Bone Mesenchymal Stem Cell Transplantation in Rats with Spinal Cord Injury

Although bone mesenchymal stem cell (BMSC) transplantation has been applied to the treatment of spinal cord injury (SCI), the effect is unsatisfactory due to the specific microenvironment (inflammation and oxidative stress) in the SCI area, which leads to the low survival rate of transplanted cells. Thus, additional strategies are required to improve the efficacy of transplanted cells in the treatment of SCI. Hydrogen possesses antioxidant and anti-inflammatory properties. However, whether hydrogen can enhance the effect of BMSC transplantation in the treatment of SCI has not yet been reported. This study was aimed at investigating whether hydrogen promotes the therapeutic effect of BMSC transplantation in the treatment of SCI in rats. In vitro, BMSCs were cultured in a normal medium and a hydrogen-rich medium to study the effect of hydrogen on the proliferation and migration of BMSCs. BMSCs were treated with a serum-deprived medium (SDM), and the effects of hydrogen on the apoptosis of BMSCs were studied. In vivo, BMSCs were injected into the rat model of SCI. Hydrogen-rich saline (5 ml/kg) and saline (5 ml/kg) were given once a day via intraperitoneal injection. Neurological function was evaluated using the Basso, Beattie, and Bresnahan (BBB) and CatWalk gait analyses. Histopathological analysis, oxidative stress, inflammatory factors (TNF-α, IL-1β, and IL-6), and transplanted cell viability were detected at 3 and 28 days after SCI. Hydrogen can significantly enhance BMSC proliferation and migration and tolerance to SDM. Hydrogen and BMSC codelivery can significantly enhance neurological function recovery by improving the transplant cell survival rate and migration. Hydrogen can enhance the migration and proliferation capacity of BMSCs to repair SCI by reducing the inflammatory response and oxidative stress in the injured area. Hydrogen and BMSC codelivery is an effective method to improve BMSC transplantation in the treatment of SCI.

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.

The mechanism of human neural stem cell secretomes improves neuropathic pain and locomotor function in spinal cord injury rat models: through antioxidant, anti-inflammatory, anti-matrix degradation, and neurotrophic activities

Background

Globally, spinal cord injury (SCI) results in a big burden, including 90% suffering permanent disability, and 60%-69% experiencing neuropathic pain. The main causes are oxidative stress, inflammation, and degeneration. The efficacy of the stem cell secretome is promising, but the role of human neural stem cell (HNSC)-secretome in neuropathic pain is unclear. This study evaluated how the mechanism of HNSC-secretome improves neuropathic pain and locomotor function in SCI rat models through antioxidant, anti-inflammatory, anti-matrix degradation, and neurotrophic activities.

Methods

A proper experimental study investigated 15 Rattus norvegicus divided into normal, control, and treatment groups (30 μL HNSC-secretome, intrathecal in the level of T10, three days post-traumatic SCI). Twenty-eight days post-injury, specimens were collected, and matrix metalloproteinase (MMP)-9, F2-Isoprostanes, tumor necrosis factor (TNF)-α, transforming growth factor (TGF)-β, and brain derived neurotrophic factor (BDNF) were analyzed. Locomotor recovery was evaluated via Basso, Beattie, and Bresnahan scores. Neuropathic pain was evaluated using the Rat Grimace Scale.

Results

The HNSC-secretome could improve locomotor recovery and neuropathic pain, decrease F2-Isoprostane (antioxidant), decrease MMP-9 and TNF-α (anti-inflammatory), as well as modulate TGF-β and BDNF (neurotrophic factor). Moreover, HNSC-secretomes maintain the extracellular matrix of SCI by reducing the matrix degradation effect of MMP-9 and increasing the collagen formation effect of TGF-β as a resistor of glial scar formation.

Conclusions

The present study demonstrated the mechanism of HNSC-secretome in improving neuropathic pain and locomotor function in SCI through antioxidant, anti-inflammatory, anti-matrix degradation, and neurotrophic activities.

Advances in Neural Stem Cell Therapy for Spinal Cord Injury: Safety, Efficacy, and Future Perspectives

Spinal cord injury (SCI) is a devastating central nervous system injury that leads to severe disabilities in motor and sensory functions, causing significant deterioration in patients' quality of life. Owing to the complexity of SCI pathophysiology, there has been no effective treatment for reversing neural tissue damage and recovering neurological functions. Several novel therapies targeting different stages of pathophysiological mechanisms of SCI have been developed. Among these, treatments using stem cells have great potential for the regeneration of damaged neural tissues. In this review, we have summarized recent preclinical and clinical studies focusing on neural stem cells (NSCs). NSCs are multipotent cells with specific differentiation capabilities for neural lineage. Several preclinical studies have demonstrated the regenerative effects of transplanted NSCs in SCI animal models through both paracrine effects and direct neuronal differentiation, restoring synaptic connectivity and neural networks. Based on the positive results of several preclinical studies, phase I and II clinical trials using NSCs have been performed. Despite several hurdles and issues that need to be addressed in the clinical use of NSCs in patients with SCI, gradual progress in the technical development and therapeutic efficacy of NSCs treatments has enhanced the prospects for cell-based treatments in SCI.

Effects of melatonin-pretreated adipose-derived mesenchymal stem cells (MSC) in an animal model of spinal cord injury

Background

One of the most serious nervous system diseases is spinal cord injury(SCI), which is increasing for various reasons. Although no definitive treatment has yet been identified for SCI, one possible treatment is adipose-derived stem cells(ADSCs). However, a key issue in transplantation is improving cells’ survival and function in the target tissue. Melatonin(MT) hormone with antioxidant properties can prolong cell survival and improve cell function. This study investigates the pre-conditioning of ADSCs with melatonin for enhancing the engraftment and neurological function of rats undergoing SCI.

Methods

42 male Sprague–Dawley rats were divided into six groups, including Control, Sham, Model, Vehicle, and Lesion treatments A and B. After acquiring white adipose tissue, stem cells were evaluated by flow cytometry. SCI was then applied in Model, Vehicle, A, and B groups. Group A and B received ADSCs and ADSCs + melatonin, respectively, 1 week after SCI, but the vehicle received only an intravenous injection for simulation; The other groups were recruited for the behavioral test. Immunohistochemistry(IHC) was used to assess the engraftment and differentiation of ADSCs in the SCI site. Basso, Beattie, and Bresnahan's score was used to evaluate motor function between the six groups.

Results

Histological studies and cell count confirmed ADSCs implantation at the injury site, which was higher in the MT-ADSCs (P < 0.001). IHC revealed the differentiation of ADSCs and MT-ADSCs into neurons, astrocytes, and oligodendrocyte lineage cells, which were higher in MT-ADSCs. Functional improvement was observed in SCI + ADSCs and SCI + MT-ADSCs groups.

Conclusion

The pre-conditioning of ADSCs with melatonin positively affects engraftment and neuronal differentiation in SCI but does not impact performance improvement compared to the ADSCs.

Analysis of gene expression profiles in two spinal cord injury models

Objectives

To analyze the changes of gene expression at different timepoints after spinal cord injury (SCI) with tenth segment thoracic injury.

Methods

Two SCI models, the complete paraplegia (H) and Allen’s strike (D) methods were applied to induce SCI in rats, and transcriptome sequencing was performed 1, 3, 7, 14, 56, and 70 days after SCI, respectively. Principal component analysis, differentially expressed gene analysis, and hierarchical clustering analysis were applied to analyze the differentially expressed genes (DEGs). Gene Ontology GO enrichment analysis, Kyoto Encyclopedia of Genes and Genomes enrichment analysis, and Gene Set Enrichment Analysis revealed the pathway of gene enrichment.

Results

There were 1,907, 3,120, 3,728, 978, 2,319, and 3,798 DEGs in the complete paraplegia group and 2,380, 878, 1,543, 6,040, 1,945, and 3,850 DEGs in the Allen’s strike method group and after SCI at 1, 3, 7, 14, 56, and 70 days, respectively. The transcriptome contours of D1, H1, D3, and H14 were clustered with C; the H56, D56, H70, and D70 transcriptome contours were similar and clustered together. H3, D7, and H7 were clustered together, and D14 was clustered separately. The transcriptome differences of the two SCI models were mainly concentrated during the first 2 weeks after SCI. The DEGs after SCI in the complete paraplegia group were more concentrated. Most of the early transcriptional regulation stabilized within 2 weeks after injury.

Conclusions

There were DEGs between the two SCI models. Through the gene changes and pathway enrichment of the entire time period after SCI, the molecular mechanism of SCI repair was revealed in depth, which provided a reference for SCI treatment in the future.

Combination Therapy Using Nanomaterials and Stem Cells to Treat Spinal Cord Injuries

As a part of the central nervous system, the spinal cord (SC) provides most of the communications between the brain and other parts of the body. Any damage to SC interrupts this communication, leading to serious problems, which may remain for the rest of their life. Due to its significant impact on patients' quality of life and its exorbitant medical costs, SC injury (SCI) is known as one of the most challengeable diseases in the world. Thus, it is critical to introduce highly translatable therapeutic platforms for SCI treatment. So far, different strategies have been introduced, among which utilizing various types of stem cells is one of the most interesting ones. The capability of stem cells to differentiate into several types of cell lines makes them promising candidates for the regeneration of injured tissues. One of the other interesting and novel strategies for SCI treatment is the application of nanomaterials, which could appear as a carrier for therapeutic agents or as a platform for culturing the cells. Combining these two approaches, stem cells and nanomaterials, could provide promising therapeutic strategies for SCI management. Accordingly, in this review we have summarized some of the recent advancements in which the applications of different types of stem cells and nanomaterials, alone and in combination forms, were evaluated for SCI treatment.

Biomaterial-Mediated Factor Delivery for Spinal Cord Injury Treatment

Spinal cord injury (SCI) is an injurious process that begins with immediate physical damage to the spinal cord and associated tissues during an acute traumatic event. However, the tissue damage expands in both intensity and volume in the subsequent subacute phase. At this stage, numerous events exacerbate the pathological condition, and therein lies the main cause of post-traumatic neural degeneration, which then ends with the chronic phase. In recent years, therapeutic interventions addressing different neurodegenerative mechanisms have been proposed, but have met with limited success when translated into clinical settings. The underlying reasons for this are that the pathogenesis of SCI is a continued multifactorial disease, and the treatment of only one factor is not sufficient to curb neural degeneration and resulting paralysis. Recent advances have led to the development of biomaterials aiming to promote in situ combinatorial strategies using drugs/biomolecules to achieve a maximized multitarget approach. This review provides an overview of single and combinatorial regenerative-factor-based treatments as well as potential delivery options to treat SCIs.

Hydrogels in Spinal Cord Injury Repair: A Review

Traffic accidents and falling objects are responsible for most spinal cord injuries (SCIs). SCI is characterized by high disability and tends to occur among the young, seriously affecting patients' lives and quality of life. The key aims of repairing SCI include preventing secondary nerve injury, inhibiting glial scarring and inflammatory response, and promoting nerve regeneration. Hydrogels have good biocompatibility and degradability, low immunogenicity, and easy-to-adjust mechanical properties. While providing structural scaffolds for tissues, hydrogels can also be used as slow-release carriers in neural tissue engineering to promote cell proliferation, migration, and differentiation, as well as accelerate the repair of damaged tissue. This review discusses the characteristics of hydrogels and their advantages as delivery vehicles, as well as expounds on the progress made in hydrogel therapy (alone or combined with cells and molecules) to repair SCI. In addition, we discuss the prospects of hydrogels in clinical research and provide new ideas for the treatment of SCI.

Research progress of endogenous neural stem cells in spinal cord injury

Spinal cord injury (SCI) is a severe disabling disease, which mainly manifests as impairments of sensory and motor functions, sexual function, bladder and intestinal functions, respiratory and cardiac functions below the injury plane. In addition, the condition has a profound effect on the mental health of patients, which often results in severe sequelae. Some patients may be paraplegic for life or even die, which places a huge burden on the family and society. There is still no effective treatment for SCI. Studies have confirmed that endogenous neural stem cells (ENSCs), as multipotent neural stem cells, which are located in the ependymal region of the central canal of the adult mammalian spinal cord, are activated after SCI and then differentiate into various nerve cells to promote endogenous repair and regeneration. However, the central canal of the spinal cord is often occluded to varying degrees in adults, and residual ependymal cells cannot be activated and do not proliferate after SCI. Besides, the destruction of the microenvironment after SCI is also an important factor that affects the proliferation and differentiation of ENSCs and spinal cord repair. Therefore, this review describes the role of ENSCs in SCI, in terms of the origin, transformation, treatment, and influencing factors, to provide new ideas for clinical treatment of SCI.

Human Adipose-Derived Stem Cells Combined with Nano-Hydrogel Promote Functional Recovery after Spinal Cord Injury in Rats

Simple Summary

Nerve regeneration and functional recovery after spinal cord injury (SCI) are worldwide problems. Scientists have achieved encouraging results in the repair of spinal cord injuries using natural or synthetic materials. In this paper, we report that nano-hydrogel combined with human adipose-derived stem cells regulate the inflammatory microenvironment, protect neurons and axons, and promote motor function recovery. In addition, three proteins related to neuronal and axonal growth were screened by Liquid chromatography-mass spectrometry. These results provide evidence for clinical treatment of spinal cord injury.

Abstract

The treatment of spinal cord injury aims to reconstruct the fiber connection and restore the interrupted neural pathways. Adipose mesenchymal stem cells (ADSCs) can promote the recovery of motor functions in spinal cord injury. However, poor survival of ADSCs and leakage outside of the injury site after local transplantation reduce the number of cells, which seriously attenuates the cumulative effect. We performed heterotopic transplantation on rats with severe spinal cord injury using human ADSCs loaded within self-assembly hydrogel RADA16-RGD (R: arginine; A: alanine; D: aspartic acid; G: glycine). Our results indicate that the combined transplantation of human ADSCs with RADA16-RGD improved the survival of ADSCs at the injured site. The inflammatory reaction was inhibited, with improved survival of the neurons and increased residual area of nerve fibers and myelin protein. The functional behaviors were promoted, as determined by the Basso, Beattie, and Bresnahan (BBB) locomotor rating scale score and electrophysiological measurements. ADSCs can promote the repair of spinal cord injury. This study provides new ideas for the treatment of spinal cord injury.

Reverse Adverse Immune Microenvironments by Biomaterials Enhance the Repair of Spinal Cord Injury

Spinal cord injury (SCI) is a severe and traumatic disorder that ultimately results in the loss of motor, sensory, and autonomic nervous function. After SCI, local immune inflammatory response persists and does not weaken or disappear. The interference of local adverse immune factors after SCI brings great challenges to the repair of SCI. Among them, microglia, macrophages, neutrophils, lymphocytes, astrocytes, and the release of various cytokines, as well as the destruction of the extracellular matrix are mainly involved in the imbalance of the immune microenvironment. Studies have shown that immune remodeling after SCI significantly affects the survival and differentiation of stem cells after transplantation and the prognosis of SCI. Recently, immunological reconstruction strategies based on biomaterials have been widely explored and achieved good results. In this review, we discuss the important factors leading to immune dysfunction after SCI, such as immune cells, cytokines, and the destruction of the extracellular matrix. Additionally, the immunomodulatory strategies based on biomaterials are summarized, and the clinical application prospects of these immune reconstructs are evaluated.

Electroacupuncture for Spinal Cord Injury: A Systematic Review and Meta-Analysis of Randomised Controlled Trials

Background

Previous studies have shown that electroacupuncture (EA) has a positive effect on motor and sensory function in patients with spinal cord injury (SCI). This review evaluated the effectiveness of EA for improvement in activities of daily living in patients with SCI.

Methods

We searched the Cochrane Library, PubMed, Web of Science, CNKI, WanFang Data, and VIP databases using a search strategy according to the guidelines of the Cochrane Handbook for Systematic Review of Interventions up to 30th September 2020. Only randomized controlled trials (RCTs) of EA in patients with SCI were included. We analyzed the data using RevMan (version 5.3) and graded the quality of evidence using GRADE profiler 3.6.1.

Results

This meta-analysis included 10 RCTs with 712 patients. Three studies revealed that the functional independence measure score for SCI patients in the EA group was higher than that in the control group (mean difference [MD] = 13.46, 95% CI: 8.00 to 18.92, P < 0.00001). Five studies showed that the modified Barthel index in the EA group was higher than that in the control group (MD = 6.92, 95% CI: 4.96 to 8.89, P < 0.00001). Five studies showed that the American Spinal Injury Association-motor score (ASIA-motor score) in the EA group was higher than that in the control group (standard MD = 0.96, 95% CI: 0.75 to 1.18, P < 0.00001). Three studies reported the ASIA-tactile and pain scores and also reported that the scores in the EA group were higher than those in the control group, with high homogeneity (tactile I² = 86%, P = 0.0008; pain I² = 54%, P = 0.11). The quality of evidence for the use of EA for improvement in motor and sensory function in SCIs was moderate according to the GRADE system.

Conclusion

This review suggested that EA improves activities of daily living and motor function in patients with SCI, with a moderate level of evidence.

Human umbilical cord mesenchymal stem cells contribute to the reconstruction of bladder function after acute spinal cord injury via p38 mitogen-activated protein kinase/nuclear factor-kappa B pathway

The association between spinal cord injury (SCI) and bladder symptoms has been intensively described. Human umbilical cord mesenchymal stem cell (hUC-MSC) treatment is beneficial to the recovery of bladder function after SCI, but its mechanism is unclear. We established an SCI model, and prepared hUC-MSCs in advance, followed by verification using flow cytometry. The Basso, Beattie and Bresnahan (BBB) score and urodynamic index were employed to evaluate motor function and bladder functions, respectively. Hematoxylin-eosin staining, luxol fast blue staining, and Masson's trichrome staining were utilized to assess pathological changes. Real-time quantitative PCR and Western blot were used to determine the mRNA and protein expressions in bladder tissues. The immunophenotypes of the HUC-MSCs were CD90⁺ and CD105⁺, but CD34^-, CD45^- and HLA-DR^-. Rats appeared severe motor dysfunction after SCI, but the BBB score was increased in hUC-MSCs after the second week. Pathologically, the improvement of the lesion area on the dorsal spinal cord, augmented anterior gray horn neuron cells of the spinal cord and lessened bladder tissue remodeling (fibrosis, collagen deposition) as well as modulated inflammation could be observed. Besides, SCI increased bladder weight, bladder capacity, urine volume and residual urine volume, and decreased urination efficiency. HUC-MSCs ameliorated SCI-induced pathological changes and bladder functions, the expressions of Collagen I, Collagen III, fibroblast growth factor 2 (FGF2), phospho-p38, transient receptor potential vanilloid 1, Toll-like receptor 4 and phospho-nuclear factor-kappa B (p-NF-κB). To sum up, HUC-MSCs contribute to the reconstruction of bladder function after SCI by repressing p38 MAPK/NF-κB pathway.

Human Umbilical Cord Mesenchymal Stem Cells Derived Exosomes Promote Neurological Function Recovery in a Rat Spinal Cord Injury Model

Spinal cord injury (SCI) often leads to personal and social-economic consequences with limited therapeutic options. Exosomes derived from human umbilical cord mesenchymal stem cells (hUC-MSC) have been explored as a promising alternative to cell therapies. In the current study, we explored the mechanism of hUC-MSC derived exosome's ameliorative effect on the spinal cord injury by combining data from in vivo contusion SCI model and in vitro cell viability of PC12 cell line stimulated with lipopolysaccharide. Intravenous administration of hUC-MSC derived exosomes dramatically improved motor function of Sprague-Dawley rats after SCI, with reduced apoptosis demonstrated by increased expression of B-cell lymphoma 2 (BCL2), decreased BCL2 associated X, apoptosis regulator (Bax), and reduced cleaved caspase 9. Conversely, exosome treatment reduced the transcription levels of astrocytes marker GFAP and microglia marker IBA1, suggesting a reduced inflammatory state from SCI injury. Furthermore, exosome treatment in vitro increased the cell viability of PC12 cells. Exosome application activated the Wnt/β-Catenin signaling in the spinal cord. Our study demonstrated that hUC-MSC derived exosomes could improve motor function through anti-apoptosis and anti-inflammatory effects. BCL2/Bax and Wnt/β-catenin signaling pathways were involved in the SCI process and could potentially mediate the protective effect of hUC-MSC derived exosomes.