Comparison of intraspinal and intrathecal implantation of induced pluripotent stem cell-derived neural precursors for the treatment of spinal cord injury in rats

Association between neural stem/progenitor cells and biomaterials in spinal cord injury therapies: A systematic review and network meta-analysis

Spinal cord injury (SCI) is associated with substantial healthcare challenges, frequently resulting in enduring sensory and motor deficits alongside various chronic complications. While advanced regenerative therapies have shown promise in preclinical research, their translation into clinical application has been limited. In response, this study utilized a comprehensive network meta-analysis to evaluate the effectiveness of neural stem/progenitor cell (NSPC) transplantation across animal models of SCI. We analyzed 363 outcomes from 55 distinct studies, categorizing the treatments into NSPCs alone (cell only), NSPCs with scaffolds (cell + scaffold), NSPCs with hydrogels (cell + hydrogel), standalone scaffolds (scaffold), standalone hydrogels (hydrogel), and control groups. Our analysis demonstrated significant enhancements in motor recovery, especially in gait function, within the NSPC treatment groups. Notably, the cell only group showed considerable improvements (standardized mean difference [SMD], 2.05; 95 % credible interval [CrI]: 1.08 to 3.10, p < 0.01), as did the cell + scaffold group (SMD, 3.73; 95 % CrI: 2.26 to 5.22, p < 0.001) and the cell + hydrogel group (SMD, 3.37; 95 % CrI: 1.02 to 5.78, p < 0.05) compared to controls. These therapeutic combinations not only reduced lesion cavity size but also enhanced neuronal regeneration, outperforming the cell only treatments. By integrating NSPCs with supportive biomaterials, our findings pave the way for refining these regenerative strategies to optimize their potential in clinical SCI treatment. Although there is no overall violation of consistency, the comparison of effect sizes between individual treatments should be interpreted in light of the inconsistency. STATEMENT OF SIGNIFICANCE: This study presents a comprehensive network meta-analysis exploring the efficacy of neural stem cell (NSC) transplantation, with and without biomaterials, in animal models of spinal cord injury (SCI). We demonstrate that NSCs, particularly when combined with biomaterials like scaffolds or hydrogels, significantly enhance motor and histological recovery post-SCI. These findings underscore the potential of NSC-based therapies, augmented with biomaterials, to advance SCI treatment, offering new insights into regenerative strategies that could significantly impact clinical practices.

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.

Inner and outer penetrating spinal cord injuries lead to distinct overground walking in mice

Spinal cord injury (SCI) is a devastating mechanical trauma. Although locomotion of model animals that mimic contusion SCI was actively examined, locomotion after penetrating SCI caused by sharp objects was not extensively studied. Severity of walking difficulty after partial transection of the spinal cord including penetrating SCI likely depends on the regions affected. Therefore, we compared beam walking and overground walking between mice after penetrating SCI at inner spinal cord region and mice with the injury at the outer region. Mice with the both penetrating SCIs did not display changes in beam walking. When appearance and movements of hindlimbs during overground walking was rated using Basso Mouse Scale for locomotion (BMS), however, mice with inner penetrating SCI showed low score shortly after the SCI. However, the score became high at later time points, as seen in contusion SCI mice. By contrast, BMS score did not decrease shortly after the outer penetrating SCI. However, the score became low 3 weeks after the SCI. As quantitative values during overground walking, movement duration in an open field were shorter at 1 day after the two penetrating SCIs. However, slower moving speed and fewer number of movement at 1 day were specific to mice with inner and outer penetrating SCIs, respectively. Moreover, BMS score was correlated with walking distance in open field only in mice with inner penetrating SCI. Thus, inner and outer penetrating SCI cause difficulty in overground walking with different severity and progress.

The role of small extracellular vesicles and microRNA as their cargo in the spinal cord injury pathophysiology and therapy

Spinal cord injury (SCI) is a devastating condition with a complex pathology that affects a significant portion of the population and causes long-term consequences. After primary injury, an inflammatory cascade of secondary injury occurs, followed by neuronal cell death and glial scar formation. Together with the limited regenerative capacity of the central nervous system, these are the main reasons for the poor prognosis after SCI. Despite recent advances, there is still no effective treatment. Promising therapeutic approaches include stem cells transplantation, which has demonstrated neuroprotective and immunomodulatory effects in SCI. This positive effect is thought to be mediated by small extracellular vesicles (sEVs); membrane-bound nanovesicles involved in intercellular communication through transport of functional proteins and RNA molecules. In this review, we summarize the current knowledge about sEVs and microRNA as their cargo as one of the most promising therapeutic approaches for the treatment of SCI. We provide a comprehensive overview of their role in SCI pathophysiology, neuroprotective potential and therapeutic effect.

Construction of functional neural network tissue combining CBD-NT3-modified linear-ordered collagen scaffold and TrkC-modified iPSC-derived neural stem cells for spinal cord injury repair

Induced pluripotent stem cells (iPSCs) can be personalized and differentiated into neural stem cells (NSCs), thereby effectively providing a source of transplanted cells for spinal cord injury (SCI). To further improve the repair efficiency of SCI, we designed a functional neural network tissue based on TrkC-modified iPSC-derived NSCs and a CBD-NT3-modified linear-ordered collagen scaffold (LOCS). We confirmed that transplantation of this tissue regenerated neurons and synapses, improved the microenvironment of the injured area, enhanced remodeling of the extracellular matrix, and promoted functional recovery of the hind limbs in a rat SCI model with complete transection. RNA sequencing and metabolomic analyses also confirmed the repair effect of this tissue from multiple perspectives and revealed its potential mechanism for treating SCI. Together, we constructed a functional neural network tissue using human iPSCs-derived NSCs as seed cells based on the interaction of receptors and ligands for the first time. This tissue can effectively improve the therapeutic effect of SCI, thus confirming the feasibility of human iPSCs-derived NSCs and LOCS for SCI repair and providing a valuable direction for SCI research.

Protocol paper: kainic acid excitotoxicity-induced spinal cord injury paraplegia in Sprague-Dawley rats

BACKGROUND

Excitotoxicity-induced in vivo injury models are vital to reflect the pathophysiological features of acute spinal cord injury (SCI) in humans. The duration and concentration of chemical treatment controls the extent of neuronal cell damage. The extent of injury is explained in relation to locomotor and behavioural activity. Several SCI in vivo methods have been reported and studied extensively, particularly contusion, compression, and transection models. These models depict similar pathophysiology to that in humans but are extremely expensive (contusion) and require expertise (compression). Chemical excitotoxicity-induced SCI models are simple and easy while producing similar clinical manifestations. The kainic acid (KA) excitotoxicity model is a convenient, low-cost, and highly reproducible animal model of SCI in the laboratory. The basic impactor approximately cost between 10,000 and 20,000 USD, while the kainic acid only cost between 300 and 500 USD, which is quite cheap as compared to traditional SCI method.

METHODS

In this study, 0.05 mM KA was administered at dose of 10 µL/100 g body weight, at a rate of 10 µL/min, to induce spinal injury by intra-spinal injection between the T12 and T13 thoracic vertebrae. In this protocol, detailed description of a dorsal laminectomy was explained to expose the spinal cord, following intra-spinal kainic acid administration at desired location. The dose, rate and technique to administer kainic acid were explained extensively to reflect a successful paraplegia and spinal cord injury in rats. The postoperative care and complication post injury of paraplegic laboratory animals were also explained, and necessary requirements to overcome these complications were also described to help researcher.

RESULTS

This injury model produced impaired hind limb locomotor function with mild seizure. Hence this protocol will help researchers to induce spinal cord injury in laboratories at extremely low cost and also will help to determine the necessary supplies, methods for producing SCI in rats and treatments designed to mitigate post-injury impairment.

CONCLUSIONS

Kainic acid intra-spinal injection at the concentration of 0.05 mM, and rate 10 µL/min, is an effective method create spinal injury in rats, however more potent concentrations of kainic acid need to be studied in order to create severe spinal injuries.

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.

A simple scoring of beam walking performance after spinal cord injury in mice

Precise evaluation of motor functions using simple and reproducible tests for mouse models of spinal cord injury (SCI) are required. Overground walking of SCI mice has been tested by Basso Mouse Scale for locomotion (BMS). In contrast, only a few works quantify walking performances of SCI mice on narrow beams, a different task. Here, we established a novel scoring system using a single beam walking apparatus for SCI mice. The scoring system uses binary judgments of values such as retention, moving forward and reaching the goal on a beam for rating. In addition, high score was given to SCI mouse when the mouse efficiently used hindlimbs for locomotion on the beam. A high rate of concordance of the score derived from positions of hindlimbs between two observers was obtained. Mice displayed the lowest total score on the beam immediately after the SCI, then the score gradually increased like time course of BMS score. Furthermore, the total scores reflected gradation of severity of SCI in 2 strains of mice. The beam walking score proved to be strongly correlated with that of BMS score, indicating that performances between overground walking and beam walking are partly correlated in SCI mice. Collectively, the novel scoring system offers an opportunity to easily evaluate motor performances of mice with SCI.

Effects of mesenchymal stem cell transplantation on spinal cord injury patients

Spinal cord injury (SCI) is a traumatic injury with sensory and motor deficits that more than 1 million patients worldwide suffer from disability due to it. Many pharmacological therapies help reduce SCI-related injury and protect CNS from more damage but no current therapy could improve the axonal repair. In this regard, stem cell therapy is considered a regenerative method for SCI patient treatment. The neurotrophic and immunomodulatory factor secretion, differentiation, neuroprotecting, and remyelinating properties have made mesenchymal stem cells (MSCs) principally useful in this field. There are studies on the role of MSCs in patients suffering from SCI. However, low number of SCI patients and the lack of control groups in these studies, the cell transplantation appropriate methods, including cell source, dose, route of delivery, and transplantation timing, are various in trials. This study reviews the beneficial effects of MSC transplantation in SCI clinical studies with a special focus on the MSC properties and limitations of MSC transplantation.

OUP accepted manuscript

Traumatic injury of the central nervous system (CNS) is a worldwide health problem affecting millions of people. Trauma of the CNS, that is, traumatic brain injury (TBI) and spinal cord injury (SCI), lead to massive and progressive cell loss and axonal degeneration, usually with very limited regeneration. At present, there are no treatments to protect injured CNS tissue or to replace the lost tissue. Stem cells are a cell type that by definition can self-renew and give rise to multiple cell lineages. In recent years, therapies using stem and progenitor cells have shown promising effects in experimental CNS trauma, particularly in the acute-subacute stage, but also in chronic injuries. However, the therapeutic mechanisms by which transplanted cells achieve the structural and/or functional improvements are often not clear. Stem cell therapies for CNS trauma can be categorized into 2 main concepts, transplantation of exogenous neural stem cells and neural progenitor cells and recruitment of endogenous stem and progenitor cells. In this review, focusing on the advances during the last decade, we will discuss the major cell therapies, the pros and cons of these 2 concepts for TBI and SCI, and the treatment strategies we believe will be successful.

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

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

Pluripotent Stem Cells for Spinal Cord Injury Repair

Spinal cord injury (SCI) is a devastating condition of the central nervous system that strongly reduces the patient’s quality of life and has large financial costs for the healthcare system. Cell therapy has shown considerable therapeutic potential for SCI treatment in different animal models. Although many different cell types have been investigated with the goal of promoting repair and recovery from injury, stem cells appear to be the most promising. Here, we review the experimental approaches that have been carried out with pluripotent stem cells, a cell type that, due to its inherent plasticity, self-renewal, and differentiation potential, represents an attractive source for the development of new cell therapies for SCI. We will focus on several key observations that illustrate the potential of cell therapy for SCI, and we will attempt to draw some conclusions from the studies performed to date.

Mesenteric Neural Stem Cell for Chronic Spinal Cord Injury: A Literature Review

Spinal cord injury (SCI) is a common and potentially life-threatening condition with no established treatment to treat the primary injury. Mesenteric neural stem cell (NSC) therapy is a promising stem cell therapy to treat primary SCI in the chronic phase. We aimed to review the literature narratively to describe current evidence regarding mesenteric NSC in SCI. Primary SCI refers to tissue damage that occurs at the time of trauma that leads to the death of neuronal cells. In chronic SCI, the ability of neuronal regeneration is compromised by the development of gliotic scar. NSC is a stem cell therapy that targeted SCI in the chronic phase. Enteric NSC is one of the sources of NSC, and autologous gut harvesting in the appendix using endoscopic surgery provides a more straightforward and low-risk procedure. Intramedullary transplantation of stem cell with ultrasound guiding is administration technique which offers long-term regeneration. Mesenteric NSC is a promising stem cell therapy to treat chronic SCI with low risk and easier procedure to isolate cells compared to other NSC sources.

Mesenchymal Stem Cells in Treatment of Spinal Cord Injury and Amyotrophic Lateral Sclerosis

Preclinical and clinical studies with various stem cells, their secretomes, and extracellular vesicles (EVs) indicate their use as a promising strategy for the treatment of various diseases and tissue defects, including neurodegenerative diseases such as spinal cord injury (SCI) and amyotrophic lateral sclerosis (ALS). Autologous and allogenic mesenchymal stem cells (MSCs) are so far the best candidates for use in regenerative medicine. Here we review the effects of the implantation of MSCs (progenitors of mesodermal origin) in animal models of SCI and ALS and in clinical studies. MSCs possess multilineage differentiation potential and are easily expandable in vitro. These cells, obtained from bone marrow (BM), adipose tissue, Wharton jelly, or even other tissues, have immunomodulatory and paracrine potential, releasing a number of cytokines and factors which inhibit the proliferation of T cells, B cells, and natural killer cells and modify dendritic cell activity. They are hypoimmunogenic, migrate toward lesion sites, induce better regeneration, preserve perineuronal nets, and stimulate neural plasticity. There is a wide use of MSC systemic application or MSCs seeded on scaffolds and tissue bridges made from various synthetic and natural biomaterials, including human decellularized extracellular matrix (ECM) or nanofibers. The positive effects of MSC implantation have been recorded in animals with SCI lesions and ALS. Moreover, promising effects of autologous as well as allogenic MSCs for the treatment of SCI and ALS were demonstrated in recent clinical studies.

Induction of Neurogenesis and Angiogenesis in a Rat Hemisection Spinal Cord Injury Model With Combined Neural Stem Cell, Endothelial Progenitor Cell, and Biomimetic Hydrogel Matrix Therapy

Acute spinal cord injury is a devastating injury that may lead to loss of independent function. Stem-cell therapies have shown promise; however, a clinically efficacious stem-cell therapy has yet to be developed. Functionally, endothelial progenitor cells induce angiogenesis, and neural stem cells induce neurogenesis. In this study, we explored using a multimodal therapy combining endothelial progenitor cells with neural stem cells encapsulated in a bioactive biomimetic hydrogel matrix to facilitate stem cell-induced neurogenesis and angiogenesis in a rat hemisection spinal cord injury model.

DESIGN

Laboratory experimentation.

SETTING

University laboratory.

SUBJECTS

Female Fischer 344 rats.

INTERVENTIONS

Three groups of rats: 1) control, 2) biomimetic hydrogel therapy, and 3) combined neural stem cell, endothelial progenitor cell, biomimetic hydrogel therapy underwent right-sided spinal cord hemisection at T9-T10. The blinded Basso, Beattie, and Bresnahan motor score was obtained weekly; after 4 weeks, observational histologic analysis of the injured spinal cords was completed.

MEASUREMENTS AND MAIN RESULTS

Blinded Basso, Beattie, and Bresnahan motor score of the hind limb revealed significantly improved motor function in rats treated with combined neural stem cell, endothelial progenitor cell, and biomimetic hydrogel therapy (p < 0.05) compared with the control group. The acellular biomimetic hydrogel group did not demonstrate a significant improvement in motor function compared with the control group. Immunohistochemistry evaluation of the injured spinal cords demonstrated de novo neurogenesis and angiogenesis in the combined neural stem cell, endothelial progenitor cell, and biomimetic hydrogel therapy group, whereas, in the control group, a gap or scar was found in the injured spinal cord.

CONCLUSIONS

This study demonstrates proof of concept that multimodal therapy with endothelial progenitor cells and neural stem cells combined with a bioactive biomimetic hydrogel can be used to induce de novo CNS tissue in an injured rat spinal cord.

Effect of combined intrathecal/intravenous injection of bone marrow derived stromal cells in platelet-rich plasma on spinal cord injury in companion animals

Background:

Companion animals are prone to spinal cord injuries commonly associated with severe locomotor and sensory complications, which can escalate to a state of irreversible paralysis. Stem cell therapies propose a hope for treating spinal cord injuries via differentiation into neurons and associated glial cells, halting the immune attacks, inhibiting apoptosis and necrosis, and secretion of neurotrophic factors that stimulate the regeneration process.

Aim:

The study aims to evaluate the use of autologous bone marrow derived stromal cells in platelet-rich plasma carrier for selected clinical cases having chronic spinal cord injuries in dogs and cats via a one-time combined intrathecal/intravenous injection.

Methods:

Cells were injected in five dogs and three cats suffering from disc protrusion leading to spinal cord injury and in thosewho did not respond to conventional treatment during a clinical trial.

Results:

Results indicated that the transplanted cells led to the restoration of the weight bearing locomotor function and spinal reflexes in a period less than 90 days with physical rehabilitation. The treatment showed minor changes in the magnetic resonance images of extruded discs.

Conclusion:

This study concluded that the combined intrathecal/intravenous injection of bone marrow stromal cells is a safe and promising procedure for treating chronic spinal cord injuries in companion animals.

Stem Cell Therapy for Spinal Cord Injury

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

Standardization of an experimental model of intradural injection after spinal cord injury in rats

OBJECTIVES

The intrathecal route has not yet been thoroughly standardized and evaluated in an experimental model of spinal cord injury (SCI) in Wistar rats. The objective of this study was to standardize and evaluate the effect of intradural injection in this animal model.

METHOD

The animals were divided into 6 groups: 1) laminectomy and intradural catheter; 2) laminectomy, intradural catheter and infusion; 3) only SCI; 4) SCI and intradural catheter; 5) SCI, intradural catheter and infusion; and 6) control (laminectomy only). Motor evaluations were performed using the Basso, Beattie and Bresnahan (BBB) scale and the horizontal ladder test; motor evoked potentials were measured for functional evaluation, and histological evaluation was performed as well. All experimental data underwent statistical analysis.

RESULTS

Regarding motor evoked potentials, the groups with experimental SCI had worse results than those without, but neither dural puncture nor the injection of intrathecal solution aggravated the effects of isolated SCI. Regarding histology, adverse tissue effects were observed in animals with SCI. On average, the BBB scores had the same statistical behaviour as the horizontal ladder results, and at every evaluated timepoint, the groups without SCI presented scored significantly better than those with SCI (p<0.05). The difference in performance on motor tests between rats with and without experimental SCI persisted from the first to the last test.

CONCLUSIONS

The present work standardizes the model of intradural injection in experimental SCI in rats. Intrathecal puncture and injection did not independently cause significant functional or histological changes.

Grafted human induced pluripotent stem cells improve the outcome of spinal cord injury: modulation of the lesion microenvironment

Spinal cord injury results in irreversible tissue damage followed by a very limited recovery of function. In this study we investigated whether transplantation of undifferentiated human induced pluripotent stem cells (hiPSCs) into the injured rat spinal cord is able to induce morphological and functional improvement. hiPSCs were grafted intraspinally or intravenously one week after a thoracic (T11) spinal cord contusion injury performed in Fischer 344 rats. Grafted animals showed significantly better functional recovery than the control rats which received only contusion injury. Morphologically, the contusion cavity was significantly smaller, and the amount of spared tissue was significantly greater in grafted animals than in controls. Retrograde tracing studies showed a statistically significant increase in the number of FB-labeled neurons in different segments of the spinal cord, the brainstem and the sensorimotor cortex. The extent of functional improvement was inversely related to the amount of chondroitin-sulphate around the cavity and the astrocytic and microglial reactions in the injured segment. The grafts produced GDNF, IL-10 and MIP1-alpha for at least one week. These data suggest that grafted undifferentiated hiPSCs are able to induce morphological and functional recovery after spinal cord contusion injury.

Spinal cord injury regeneration using autologous bone marrow-derived neurocytes and rat embryonic stem cells: A comparative study in rats

BACKGROUND

Spinal cord injury (SCI) is an important cause of traumatic paralysis and is mainly due to motor vehicle accidents. However, there is no definite treatment for spinal cord damage.

AIM

To assess the outcome of rat embryonic stem cells (rESC) and autologous bone marrow-derived neurocytes (ABMDN) treatment in iatrogenic SCI created in rats, and to compare the efficacy of the two different cell types.

METHODS

The study comprised 45 male Wistar rats weighing between 250 and 300 g, which were divided into three groups, the control, rESC and ABMDN groups. The anesthetized animals underwent exposure of the thoracic 8th to lumbar 1st vertebrae. A T10-thoracic 12th vertebrae laminectomy was performed to expose the spinal cord. A drop-weight injury using a 10 g weight from a height of 25 cm onto the exposed spinal cord was conducted. The wound was closed in layers. The urinary bladder was manually evacuated twice daily and after each evacuation Ringer lactate 5 mL/100 g was administered, twice daily after each bladder evacuation for the first 7 postoperative days. On the 10th day, the rats underwent nerve conduction studies and behavioral assessment [Basso, Beattie, Brenham (BBB)] to confirm paraplegia. Rat embryonic stem cells, ABMDN and saline were injected on the 10th day. The animals were euthanized after 8 wk and the spinal cord was isolated, removed and placed in 2% formalin for histopathological analysis to assess the healing of neural tissues at the axonal level.

RESULTS

All the animals tolerated the procedure well. The BBB scale scoring showed that at the end of the first week no recovery was observed in the groups. Post-injection, there was a strong and significant improvement in rats receiving rESC and ABMDN as compared to the control group based on the BBB scale, and the Train-of-four-Watch SX acceleromyography device exhibited statistically significant (P < 0.0001) regeneration of neural tissue after SCI. Histological evaluation of the spinal cord showed maximum vacuolization and least gliosis in the control group compared to the rESC and ABMDN treated animals. In the ABMDN group, limited vacuolization and more prominent gliosis were observed in all specimens as compared to the control and rESC groups.

CONCLUSION

This study provided strong evidence to support that transplantation of rESC and ABMDN can improve functional recovery after iatrogenic SCI. The transplanted cells showed a beneficial therapeutic effect when compared to the control group.

Transplantation of Neural Precursors Derived from Induced Pluripotent Cells Preserve Perineuronal Nets and Stimulate Neural Plasticity in ALS Rats

A promising therapeutic strategy for amyotrophic lateral sclerosis (ALS) treatment is stem cell therapy. Neural progenitors derived from induced pluripotent cells (NP-iPS) might rescue or replace dying motoneurons (MNs). However, the mechanisms responsible for the beneficial effect are not fully understood. The aim here was to investigate the mechanism by studying the effect of intraspinally injected NP-iPS into asymptomatic and early symptomatic superoxide dismutase (SOD)1^G93A transgenic rats. Prior to transplantation, NP-iPS were characterized in vitro for their ability to differentiate into a neuronal phenotype. Motor functions were tested in all animals, and the tissue was analyzed by immunohistochemistry, qPCR, and Western blot. NP-iPS transplantation significantly preserved MNs, slowed disease progression, and extended the survival of all treated animals. The dysregulation of spinal chondroitin sulfate proteoglycans was observed in SOD1^G93A rats at the terminal stage. NP-iPS application led to normalized host genes expression (versican, has-1, tenascin-R, ngf, igf-1, bdnf, bax, bcl-2, and casp-3) and the protection of perineuronal nets around the preserved MNs. In the host spinal cord, transplanted cells remained as progenitors, many in contact with MNs, but they did not differentiate. The findings suggest that NP-iPS demonstrate neuroprotective properties by regulating local gene expression and regulate plasticity by modulating the central nervous system (CNS) extracellular matrix such as perineuronal nets (PNNs).

Human Pluripotent Stem Cells for Spinal Cord Injury

Spinal cord injury (SCI) as a serious public health issue and neurological insult is one of the most severe cause of long-term disability. To date, a variety of techniques have been widely developed to treat central nervous system injury. Currently, clinical treatments are limited to surgical decompression and pharmacotherapy. Because of their negative effects and inefficiency, novel therapeutic approaches are required in the management of SCI. Improvement and innovation of stem cell-based therapies have a huge potential for biological and future clinical applications. Human pluripotent stem cells (hPSCs) including embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) are defined by their abilities to divide asymmetrically, self-renew and ultimately differentiate into various cell lineages. There are considerable research efforts to use various types of stem cells, such as ESCs, neural stem cells (NSCs), and mesenchymal stem cells (MSCs) in the treatment of patients with SCI. Moreover, the use of patient-specific iPSCs holds great potential as an unlimited cell source for generating in vivo models of SCI. In this review, we focused on the potential of hPSCs in treating SCI.

Progress in Stem Cell Therapy for Spinal Cord Injury

Background

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

Methods

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

Results

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

Conclusion

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

New Model of Ventral Spinal Cord Lesion Induced by Balloon Compression in Rats

Despite the variety of experimental models of spinal cord injury (SCI) currently used, the model of the ventral compression cord injury, which is commonly seen in humans, is very limited. Ventral balloon compression injury reflects the common anatomical mechanism of a human lesion and has the advantage of grading the injury severity by controlling the inflated volume of the balloon. In this study, ventral compression of the SCI was performed by the anterior epidural placement of the balloon of a 2F Fogarty's catheter, via laminectomy, at the level of T10. The balloon was rapidly inflated with 10 or 15 μL of saline and rested in situ for 5 min. The severity of the lesion was assessed by behavioral and immunohistochemical tests. Compression with the volume of 15 μL resulted in severe motor and sensory deficits represented by the complete inability to move across a horizontal ladder, a final Basso, Beattie and Bresnahan (BBB) score of 7.4 and a decreased withdrawal time in the plantar test (11.6 s). Histology and immunohistochemistry revealed a significant loss of white and gray matter with a loss of motoneuron, and an increased size of astrogliosis. An inflation volume of 10 μL resulted in a mild transient deficit. There are no other balloon compression models of ventral spinal cord injury. This study provided and validated a novel, easily replicable model of the ventral compression SCI, introduced by an inflated balloon of Fogarty´s catheter. For a severe incomplete deficit, an inflated volume should be maintained at 15 μL.

Clinical Trials of Stem Cell Treatment for Spinal Cord Injury

There are more than one million patients worldwide suffering paralysis caused by spinal cord injury (SCI). SCI causes severe socioeconomic problems not only to the patients and their caregivers but also to society; therefore, the development of innovative treatments is crucial. Many pharmacological therapies have been attempted in an effort to reduce SCI-related damage; however, no single therapy that could dramatically improve the serious long-term sequelae of SCI has emerged. Stem cell transplantation therapy, which can ameliorate damage or regenerate neurological networks, has been proposed as a promising candidate for SCI treatment, and many basic and clinical experiments using stem cells for SCI treatment have been launched, with promising results. However, the cell transplantation methods, including cell type, dose, transplantation route, and transplantation timing, vary widely between trials, and there is no consensus regarding the most effective treatment strategy. This study reviews the current knowledge on this issue, with a special focus on the clinical trials that have used stem cells for treating SCI, and highlights the problems that remain to be solved before the widespread clinical use of stem cells can be adopted.

Cell Therapeutic Strategies for Spinal Cord Injury

Significance: Spinal cord injury (SCI) is a neurological disorder that resulted from destroyed long axis of spinal cord, affecting thousands of people every year. With the occurrence of SCI, the lesions can form cystic cavities and produce glial scar, myelin inhibitor, and inflammation that negatively impact repair of spinal cord. Therefore, SCI remains a difficult problem to overcome with present therapeutics. This review of cell therapeutics in SCI provides a systematic review of combinatory therapeutics of SCI and helps the realization of regeneration of spinal cord in the future. Recent Advances: With major breakthroughs in neurobiology in recent years, present therapeutic strategies for SCI mainly aim at nerve regeneration or neuroprotection. For nerve regeneration, the application approaches are tissue engineering and cell transplantation, while drug therapeutics is applied for neuroprotection. Cell therapeutics is a new approach that treats SCI by cell transplantation. Cell therapeutics possesses advantages of neuroprotection, immune regulation, axonal regeneration, neuron relay formation, and remyelination. Critical Issues: Neurons cannot regenerate at the site of injury. Therefore, it is essential to find a repair strategy for remyelination, axon regeneration, and functional recovery. Cell therapeutics is emerging as the most promising approach for treating SCI. Future Directions: The future application of SCI therapy in clinical practice may require a combination of multiple strategies. A comprehensive treatment of injury of spinal cord is the focus of the present research. With the combination of different cell therapy strategies, future experiments will achieve more dramatic success in spinal cord repair.

Spinal cord injury: pathophysiology, treatment strategies, associated challenges, and future implications

Axonal regeneration and formation of tripartite (axo-glial) junctions at damaged sites is a prerequisite for early repair of injured spinal cord. Transplantation of stem cells at such sites of damage which can generate both neuronal and glial population has gained impact in terms of recuperation upon infliction with spinal cord injury. In spite of the fact that a copious number of pre-clinical studies using different stem/progenitor cells have shown promising results at acute and subacute stages, at the chronic stages of injury their recovery rates have shown a drastic decline. Therefore, developing novel therapeutic strategies are the need of the hour in order to assuage secondary morbidity and effectuate improvement of the spinal cord injury (SCI)-afflicted patients' quality of life. The present review aims at providing an overview of the current treatment strategies and also gives an insight into the potential cell-based therapies for the treatment of SCI.

Filling the Gap: Neural Stem Cells as A Promising Therapy for Spinal Cord Injury

Spinal cord injury (SCI) can lead to severe motor, sensory and social impairments having a huge impact on patients’ lives. The complex and time-dependent SCI pathophysiology has been hampering the development of novel and effective therapies. Current treatment options include surgical interventions, to stabilize and decompress the spinal cord, and rehabilitative care, without providing a cure for these patients. Novel therapies have been developed targeting different stages during trauma. Among them, cell-based therapies hold great potential for tissue regeneration after injury. Neural stem cells (NSCs), which are multipotent cells with inherent differentiation capabilities committed to the neuronal lineage, are especially relevant to promote and reestablish the damaged neuronal spinal tracts. Several studies demonstrate the regenerative effects of NSCs in SCI after transplantation by providing neurotrophic support and restoring synaptic connectivity. Therefore, human clinical trials have already been launched to assess safety in SCI patients. Here, we review NSC-based experimental studies in a SCI context and how are they currently being translated into human clinical trials.

Drugs for Targeted Therapies of Alzheimer's Disease

Alzheimer's disease (AD) is one type of neurodegenerative diseases, which is prevalent in the elderly. Beta-amyloid (Aβ) plaques and phosphorylated tau-induced neurofibrillary tangles are two pathological hallmarks of this disease and the corresponding pathological pathways of these hallmarks are considered as the therapeutic targets. There are many drugs scheduled for pre-clinical and clinical trial that target to inhibit the initiators of pathological Aβ and tau aggregates as well as critical Aβ secretases and kinases in tau hyperphosphorylation. In addition, studies in disease gene variations, and detection of key prognostic effectors in early development are also important for AD control. The discovery of potential drug targets contributed to targeted therapy in a stage-dependent manner, However, there are still some issues that cause concern such as the low bioavailability and low efficacy of candidate drugs from clinical trial reports. Therefore, modification of drug candidates and development of delivery agents are essential and critical. With other medical advancements like cell replacement therapy, there is hope for the cure of Alzheimer's disease in the foreseeable future.

Multifunctionalized hydrogels foster hNSC maturation in 3D cultures and neural regeneration in spinal cord injuries

Cells reside in 3D microenvironments in living tissues; consequently, 3D cultures gained great interest because they better mimic the natural conditions of cells. Self-assembling peptides (SAPs) are synthetic bioabsorbable biomaterials that can provide customized 3D microenvironments regulating cell functionalities and tissue repair. Here we introduce a SAP-hydrogel designed to support human neural stem cell (hNSC) differentiation in 3D serum-free conditions, generating mature and active human neurons in vitro. We also demonstrate its functional neurorigenerative potential in rat spinal cord injuries, peaking when seeded with hNSCs progeny predifferentiated in vitro for 6 weeks. Despite these promising results, this approach should be confirmed in the future with medium-size animal models and with additional and refined behavioral tests before entering a clinical trial.

Three-dimensional cell cultures are leading the way to the fabrication of tissue-like constructs useful to developmental biology and pharmaceutical screenings. However, their reproducibility and translational potential have been limited by biomaterial and culture media compositions, as well as cellular sources. We developed a construct comprising synthetic multifunctionalized hydrogels, serum-free media, and densely seeded good manufacturing practice protocol-grade human neural stem cells (hNSC). We tracked hNSC proliferation, differentiation, and maturation into GABAergic, glutamatergic, and cholinergic neurons, showing entangled electrically active neural networks. The neuroregenerative potential of the “engineered tissue” was assessed in spinal cord injuries, where hNSC-derived progenitors and predifferentiated hNSC progeny, embedded in multifunctionalized hydrogels, were implanted. All implants decreased astrogliosis and lowered the immune response, but scaffolds with predifferentiated hNSCs showed higher percentages of neuronal markers, better hNSC engraftment, and improved behavioral recovery. Our hNSC-construct enables the formation of 3D functional neuronal networks in vitro, allowing novel strategies for hNSC therapies in vivo.

Progress in the Use of Induced Pluripotent Stem Cell-Derived Neural Cells for Traumatic Spinal Cord Injuries in Animal Populations: Meta-Analysis and Review

Induced pluripotent stem cells (iPSCs) are cells genetically reprogrammed from somatic cells, which can be differentiated into neurological lineages with the aim to replace or assist damaged neurons in the treatment of spinal cord injuries (SCIs) caused by physical trauma. Here, we review studies addressing the functional use of iPSC‐derived neural cells in SCIs and perform a meta‐analysis to determine if significant motor improvement is restored after treatment with iPSC‐derived neural cells compared with treatments using embryonic stem cell (ESC)‐derived counterpart cells and control treatments. Overall, based on locomotion scales in rodents and monkeys, our meta‐analysis indicates a therapeutic benefit for SCI treatment using neural cells derived from either iPSCs or ESCs, being this of importance due to existing ethical and immunological complications using ESCs. Results from these studies are evidence of the successes and limitations of iPSC‐derived neural cells in the recovery of motor capacity. stem cells translational medicine2019;8:681&693

Stem cell transplantation and functional recovery after spinal cord injury: a systematic review and meta-analysis

Spinal cord injury is a significant cause of motor dysfunctions. There is no definite cure for it, and most of the therapeutic modalities are only symptomatic treatment. In this systematic review and meta-analysis, the effectiveness of stem cell therapy in the treatment of the spinal cord injuries in animal models was studied and evaluated. A systematic search through medical databases by using appropriate keywords was conducted. The relevant reports were reviewed in order to find out cases in which inclusion and exclusion criteria had been fulfilled. Finally, 89 articles have been considered, from which 28 had sufficient data for performing statistical analyses. The findings showed a significant improvement in motor functions after cell therapy. The outcome was strongly related to the number of transplanted cells, site of injury, chronicity of the injury, type of the damage, and the induction of immune-suppression. According to our data, improvements in functional recovery after stem cell therapy in the treatment of spinal cord injury in animal models was noticeable, but its outcome is strongly related to the site of injury, number of transplanted cells, and type of transplanted cells.

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

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

Stem Cells Therapy for Spinal Cord Injury

Spinal cord injury (SCI), a serious public health issue, most likely occurs in previously healthy young adults. Current therapeutic strategies for SCI includes surgical decompression and pharmacotherapy, however, there is still no gold standard for the treatment of this devastating condition. Inefficiency and adverse effects of standard therapy indicate that novel therapeutic strategies are required. Because of their neuroregenerative and neuroprotective properties, stem cells are a promising tool for the treatment of SCI. Herein, we summarize and discuss the promising therapeutic potential of human embryonic stem cells (hESC), induced pluripotent stem cells (iPSC) and ependymal stem/progenitor cells (epSPC) for SCI.

The Effect of Botulinum Neurotoxin Serotype a Heavy Chain on the Growth Related Proteins and Neurite Outgrowth after Spinal Cord Injury in Rats

(1) Background: The botulinum toxin A (BoNT-A) heavy chain (HC) can stimulate the growth of primary motor neurites. (2) Methods: A recombinant BoNT/A HC was injected locally plus interval intrathecal catheter of BoNT/A HC to rats with ipsilateral semi-dissociated lumbar spinal cord injuries (SCIs). First, 2D gel with a silver nitrate stain was applied to detect the general pattern of protein expression. Growth associated protein 43 (GAP-43) and superior cervical ganglion 10 (SCG10) were chosen to represent the altered proteins, based on their molecular weight and pI, and were used to further detect their expression. Meanwhile, the neuronal processes were measured. The measurements of thermal hyperalgesia and grasp power at the ipsilateral hindlimb were used to evaluate spinal sensory and motor function, respectively. (3) Results: The local injection of BoNT/A HC followed by its intrathecal catheter intervally altered the spinal protein expression pattern after an SCI; protein expression was similar to normal levels or displayed a remarkable increase. The changes in the expression and distribution of phosphorylated growth associated protein 43(p-GAP 43) and superior cervical ganglion 10 (SCG 10) indicated that the administration of BoNT/A HC to the SCI significantly amplified the expression of p-GAP43 and SCG10 (p < 0.05). Meanwhile, the positive immunofluorescent staining for both p-GAP43 and SCG10 was mainly present near the rostral aspect of the injury, both in the cytoplasm and the neuronal processes. Moreover, the outgrowth of neurites was stimulated by the BoNT/A HC treatment; this was evident from the increase in neurite length, number of branches and the percentage of cells with neuronal processes. The results from the spinal function tests suggested that the BoNT/A HC did not affect sensation, but had a large role in improving the ipsilateral hindlimb grasp power (p < 0.05). (4) Conclusions: The local injection with the intermittent intrathecal administration of BoNT/A heavy chain to rats with SCI increased the local expression of GAP-43 and SCG 10, which might be affiliated with the regeneration of neuronal processes surrounding the injury, and might also be favorable to the relief of spinal motor dysfunction.

Neural Stem Cells Derived from Human-Induced Pluripotent Stem Cells and Their Use in Models of CNS Injury

Induced pluripotent stem (iPS) cells are derived from differentiated cells by different reprogramming techniques, by introducing specific transcription factors responsible for pluripotency. Induced pluripotent stem cells can serve as an excellent source for differentiated neural stem/progenitor cells (NSCs/NPs). Several methods and protocols are utilized to create a robust number of NSCs/NPs without jeopardizing the safety issues required for in vivo applications. A variety of disease-specific iPS cells have been used to study nervous system diseases. In this chapter, we will focus on some of the derivation and differentiation approaches and the application of iPS-NPs in the treatment of spinal cord injury and stroke.

The effects of oxyresveratrol abrogates inflammation and oxidative stress in rat model of spinal cord injury

Oxyresveratrol and its glycoside are important natural active materials. As an effective tyrosine kinase inhibitor, oxyresveratrol may prevent herpes virus infection, inflammation and oxidative stress, as well as protect nerves. In addition, it is known to inhibit cell apoptosis following cerebral ischemia. In recent years, oxyresveratrol and its glycoside have been widely investigated, and their useful biological activities have been explored, indicating that they may be worthy of further comprehensive research. The aim of the present study was to evaluate the photoprotective effects of oxyresveratrol and its ability to abrogate inflammation and oxidative stress in a rat model of spinal cord injury (SCI). The authors identified that oxyresveratrol significantly reversed the SCI‑induced inhibition of Basso, Beattie, and Bresnahan scores, inhibited the SCI‑mediated increase in spinal cord water content, significantly suppressed SCI‑induced nuclear factor‑κB/p65, tumor necrosis factor‑α, interleukin (IL)‑1β and IL‑6 activities and reversed the malondialdehyde, superoxide dismutase, glutathione (GSH) and GSH peroxidase activities in SCI rats. SCI‑induced granulocyte‑macrophage colony‑stimulating factor (GM‑CSF), inducible nitric oxide synthase (iNOS) and cyclo‑oxygenase‑2 (COX‑2) protein expression was significantly suppressed by oxyresveratrol, and SCI‑mediated inhibition of nuclear factor (erythroid‑derived 2)‑like 2 (Nrf2) protein expression was significantly increased by oxyresveratrol. In conclusion, these results suggest that the effects of oxyresveratrol restores SCI, and abrogates inflammation and oxidative stress in rat model of SCI via the GM‑CSF, iNOS, COX‑2 and Nrf2 signaling pathway.

Meta-analysis of stem cell transplantation for reflex hypersensitivity after spinal cord injury

Stem cells have been used in novel therapeutic strategies for spinal cord injury (SCI), but the effect of stem cell transplantation on neuropathic pain after SCI is unclear. The current meta-analysis evaluates the effects of stem cell transplantation on neuropathic pain after SCI. We first conducted online searches of PubMed, Web of Science, China Academic Journals Full-text Database, and Wanfang Data for randomized controlled trials that compared stem cell transplantation and vehicle treatments in rodent models of neuropathic pain after SCI. Quality assessment was performed using Cochrane Reviewer's Handbook 5.1.0, and meta-analysis was conducted with RevMan 5.3. Then, we developed a rat model of SCI and transplanted bone marrow mesenchymal stem cells to verify meta-analysis results. Twelve randomized, controlled trials (n=354 total animals) were included in our meta-analysis and divided by subgroups, including species, timing of behavioral measurements, and transplantation time after SCI. Subgroup analysis of these 12 studies indicated that stem cell-treated animals had a higher mechanical reflex threshold than vehicle groups, with a significant difference in both rats and mice. The thermal withdrawal latency showed the same results in mouse subgroups, but not in rat subgroups. In addition, mesenchymal stem cell transplantation was an effective treatment for mechanical, but not thermal reflex hypersensitivity relief in rats. Transplantation showed a positive effect when carried out at 3 or 7days post-SCI. Stem cell transplantation alleviates mechanical reflex hypersensitivity in rats and mice and thermal reflex hypersensitivity in mice after SCI.

Does vitamin C have the ability to augment the therapeutic effect of bone marrow-derived mesenchymal stem cells on spinal cord injury?

Methylprednisolone (MP) is currently the only drug confirmed to exhibit a neuroprotective effect on acute spinal cord injury (SCI). Vitamin C (VC) is a natural water-soluble antioxidant that exerts neuroprotective effects through eliminating free radical damage to nerve cells. Bone marrow mesenchymal stem cells (BMMSCs), as multipotent stem cells, are promising candidates in SCI repair. To evaluate the therapeutic effects of MP, VC and BMMSCs on traumatic SCI, 80 adult male rats were randomly divided into seven groups: control, SCI (SCI induction by weight-drop method), MP (SCI induction, followed by administration of 30 mg/kg MP via the tail vein, once every other 6 hours, for five times), VC (SCI induction, followed by intraperitoneal administration of 100 mg/kg VC once a day, for 28 days), MP + VC (SCI induction, followed by administration of MP and VC as the former), BMMSCs (SCI induction, followed by injection of 3 × 10⁶ BMMSCs at the injury site), and BMMSCs + VC (SCI induction, followed by BMMSCs injection and VC administration as the former). Locomotor recovery was assessed using the Basso Mouse Scale. Injured spinal cord tissue was evaluated using hematoxylin-eosin staining and immunohistochemical staining. Expression of transforming growth factor-beta, tumor necrosis factor-alpha, and matrix metalloproteinase-2 genes was determined using real-time quantitative PCR. BMMSCs intervention better promoted recovery of nerve function of rats with SCI, mitigated nerve cell damage, and decreased expression of transforming growth factor-beta, tumor necrosis factor-alpha, and matrix metalloproteinase-2 genes than MP and/or VC. More importantly, BMMSCs in combination with VC induced more obvious improvements. These results suggest that VC can enhance the neuroprotective effects of BMMSCs against SCI.

Stem Cells and Labeling for Spinal Cord Injury

Spinal cord injury (SCI) is a devastating condition that usually results in sudden and long-lasting locomotor and sensory neuron degeneration below the lesion site. During the last two decades, the search for new therapies has been revolutionized with the improved knowledge of stem cell (SC) biology. SCs therapy offers several attractive strategies for spinal cord repair. The transplantation of SCs promotes remyelination, neurite outgrowth and axonal elongation, and activates resident or transplanted progenitor cells across the lesion cavity. However, optimized growth and differentiation protocols along with reliable safety assays should be established prior to the clinical application of SCs. Additionally, the ideal method of SCs labeling for efficient cell tracking after SCI remains a challenging issue that requires further investigation. This review summarizes the current findings on the SCs-based therapeutic strategies, and compares different SCs labeling approaches for SCI.

A Comparative Study of Three Different Types of Stem Cells for Treatment of Rat Spinal Cord Injury

Three different sources of human stem cells-bone marrow-derived mesenchymal stem cells (BM-MSCs), neural progenitors (NPs) derived from immortalized spinal fetal cell line (SPC-01), and induced pluripotent stem cells (iPSCs)-were compared in the treatment of a balloon-induced spinal cord compression lesion in rats. One week after lesioning, the rats received either BM-MSCs (intrathecally) or NPs (SPC-01 cells or iPSC-NPs, both intraspinally), or saline. The rats were assessed for their locomotor skills (BBB, flat beam test, and rotarod). Morphometric analyses of spared white and gray matter, axonal sprouting, and glial scar formation, as well as qPCR and Luminex assay, were conducted to detect endogenous gene expression, while inflammatory cytokine levels were performed to evaluate the host tissue response to stem cell therapy. The highest locomotor recovery was observed in iPSC-NP-grafted animals, which also displayed the highest amount of preserved white and gray matter. Grafted iPSC-NPs and SPC-01 cells significantly increased the number of growth-associated protein 43 (GAP43+) axons, reduced astrogliosis, downregulated Casp3 expression, and increased IL-6 and IL-12 levels. hMSCs transiently decreased levels of inflammatory IL-2 and TNF-α. These findings correlate with the short survival of hMSCs, while NPs survived for 2 months and matured slowly into glia- and tissue-specific neuronal precursors. SPC-01 cells differentiated more in astroglial phenotypes with a dense structure of the implant, whereas iPSC-NPs displayed a more neuronal phenotype with a loose structure of the graft. We concluded that the BBB scores of iPSC-NP- and hMSC-injected rats were superior to the SPC-01-treated group. The iPSC-NP treatment of spinal cord injury (SCI) provided the highest recovery of locomotor function due to robust graft survival and its effect on tissue sparing, reduction of glial scarring, and increased axonal sprouting.

Neurogenic Bladder Repair Using Autologous Mesenchymal Stem Cells

The normal function of the urinary bladder is to store and expel urine in a coordinated, controlled fashion, the activity of which is regulated by the central and peripheral nervous systems. Neurogenic bladder is a term applied to a malfunctioning urinary bladder due to neurologic dysfunction or insult emanating from internal or external trauma, disease, or injury. This report describes a case of neurogenic bladder following laminectomy procedure and long-standing diabetes mellitus with neuropathy treated with autologous cellular therapy. The differentiation potential and paracrine effects of mesenchymal stem cells on bladder function have been highlighted.

In Vivo Assessment of Phage and Linezolid Based Implant Coatings for Treatment of Methicillin Resistant S. aureus (MRSA) Mediated Orthopaedic Device Related Infections

Staphylococcus comprises up to two-thirds of all pathogens in orthopaedic implant infections with two species respectively Staphylococcus aureus and Staphylococcus epidermidis, being the predominate etiological agents isolated. Further, with the emergence of methicillin-resistant S. aureus (MRSA), treatment of S. aureus implant infections has become more difficult, thus representing a devastating complication. Use of local delivery system consisting of S.aureus specific phage along with linezolid (incorporated in biopolymer) allowing gradual release of the two agents at the implant site represents a new, still unexplored treatment option (against orthopaedic implant infections) that has been studied in an animal model of prosthetic joint infection. Naked wire, hydroxypropyl methylcellulose (HPMC) coated wire and phage and /or linezolid coated K-wire were surgically implanted into the intra-medullary canal of mouse femur bone of respective groups followed by inoculation of S.aureus ATCC 43300(MRSA). Mice implanted with K-wire coated with both the agents i.e phage as well as linezolid (dual coated wires) showed maximum reduction in bacterial adherence, associated inflammation of the joint as well as faster resumption of locomotion and motor function of the limb. Also, all the coating treatments showed no emergence of resistant mutants. Use of dual coated implants incorporating lytic phage (capable of self-multiplication) as well as linezolid presents an attractive and aggressive early approach in preventing as well as treating implant associated infections caused by methicillin resistant S. aureus strains as assessed in a murine model of experimental joint infection.