Synergic effects of EPI-NCSCs and OECs on the donor cells migration, the expression of neurotrophic factors, and locomotor recovery of contused spinal cord of rats

Epidermal Neural Crest Stem Cell Conditioned Medium Enhances Spinal Cord Injury Recovery via PI3K/AKT-Mediated Neuronal Apoptosis Suppression

This study aimed to assess the impact of conditioned medium from epidermal neural crest stem cells (EPI-NCSCs-CM) on functional recovery following spinal cord injury (SCI), while also exploring the involvement of the PI3K-AKT signaling pathway in regulating neuronal apoptosis. EPI-NCSCs were isolated from 10-day-old Sprague-Dawley rats and cultured for 48 h to obtain EPI-NCSC-CM. SHSY-5Y cells were subjected with H2O2 treatment to induce apoptosis. Cell viability and survival rates were evaluated using the CCK-8 assay and calcein-AM/PI staining. SCI contusion model was established in adult Sprague-Dawley rats to assess functional recovery, utilizing the Basso, Beattie and Bresnahan (BBB) scoring system, inclined test, and footprint observation. Neurological restoration after SCI was analyzed through electrophysiological recordings. Histological analysis included hematoxylin and eosin (H&E) staining and Nissl staining to evaluate tissue organization. Apoptosis and oxidative stress levels were assessed using TUNEL staining and ROS detection methods. Additionally, western blotting was performed to examine the expression of apoptotic markers and proteins related to the PI3K/AKT signaling pathway. EPI-NCSC-CM significantly facilitated functional and histological recovery in SCI rats by inhibiting neuronal apoptosis through modulation of the PI3K/AKT pathway. Administration of EPI-NCSCs-CM alleviated H2O2-induced neurotoxicity in SHSY-5Y cells in vitro. The use of LY294002, a PI3K inhibitor, underscored the crucial role of the PI3K/AKT signaling pathway in regulating neuronal apoptosis. This study contributes to the ongoing exploration of molecular pathways involved in spinal cord injury (SCI) repair, focusing on the therapeutic potential of EPI-NCSC-CM. The research findings indicate that EPI-NCSC-CM exerts a neuroprotective effect by suppressing neuronal apoptosis through activation of the PI3K/AKT pathway in SCI rats. These results highlight the promising role of EPI-NCSC-CM as a potential treatment strategy for SCI, emphasizing the significance of the PI3K/AKT pathway in mediating its beneficial effects.

Olfactory ensheathing cells as candidate cells for chronic pain treatment

Chronic pain is often accompanied by tissue damage and pain hypersensitivity. It easily relapses and is challenging to cure, which seriously affects the patients' quality of life and is an urgent problem to be solved. Current treatment methods primarily rely on morphine drugs, which do not address the underlying nerve injury and may cause adverse reactions. Therefore, in recent years, scientists have shifted their focus from chronic pain treatment to cell transplantation. This review describes the classification and mechanism of chronic pain through the introduction of the characteristics of olfactory ensheathing cells (OECs), an in-depth discussion of special glial cells through the phagocytosis of nerve debris, receptor-ligand interactions, providing nutrition, and other inhibition of neuroinflammation, and ultimately supporting axon regeneration and mitigation of chronic pain. This review summarizes the potential and limitations of OECs for treating chronic pain by objectively analyzing relevant clinical trials and methods to enhance efficacy and future development prospects.

Considering the Cellular Composition of Olfactory Ensheathing Cell Transplants for Spinal Cord Injury Repair: A Review of the Literature

Olfactory ensheathing cells (OECs) are specialized glia cells of the olfactory system that support the continual regeneration of olfactory neurons throughout adulthood. Owing to their pro-regenerative properties, OECs have been transplanted in animal models of spinal cord injuries (SCI) and trialed in clinical studies on SCI patients. Although these studies have provided convincing evidence to support the continued development of OEC transplantation as a treatment option for the repair of SCI, discrepancies in the reported outcome has shown that OEC transplantation requires further improvement. Much of the variability in the reparative potential of OEC transplants is due to the variations in the cell composition of transplants between studies. As a result, the optimal cell preparation is currently a subject of debate. Here we review, the characterization as well as the effect of the cell composition of olfactory cell transplantation on therapeutic outcome in SCI. Firstly, we summarize and review the cell composition of olfactory cell preparations across the different species studied prior to transplantation. Since the purity of cells in olfactory transplants might affect the study outcome we also examine the effect of the proportions of OECs and the different cell types identified in the transplant on neuroregeneration. Finally, we consider the effect of the yield of cells on neuroregeneration by assessing the cell dose of transplants on therapeutic outcome.

Delivery of chondroitinase by canine mucosal olfactory ensheathing cells alongside rehabilitation enhances recovery after spinal cord injury

Spinal cord injury (SCI) can cause chronic paralysis and incontinence and remains a major worldwide healthcare burden, with no regenerative treatment clinically available. Intraspinal transplantation of olfactory ensheathing cells (OECs) and injection of chondroitinase ABC (chABC) are both promising therapies but limited and unpredictable responses are seen, particularly in canine clinical trials. Sustained delivery of chABC presents a challenge due to its thermal instability; we hypothesised that transplantation of canine olfactory mucosal OECs genetically modified ex vivo by lentiviral transduction to express chABC (cOEC-chABC) would provide novel delivery of chABC and synergistic therapy. Rats were randomly divided into cOEC-chABC, cOEC, or vehicle transplanted groups and received transplant immediately after dorsal column crush corticospinal tract (CST) injury. Rehabilitation for forepaw reaching and blinded behavioural testing was conducted for 8 weeks. We show that cOEC-chABC transplanted animals recover greater forepaw reaching accuracy on Whishaw testing and more normal gait than cOEC transplanted or vehicle control rats. Increased CST axon sprouting cranial to the injury and serotonergic fibres caudal to the injury suggest a mechanism for recovery. We therefore demonstrate that cOECs can deliver sufficient chABC to drive modest functional improvement, and that this genetically engineered cellular and molecular approach is a feasible combination therapy for SCI.

Combination therapy with astaxanthin and epidermal neural crest stem cells improves motor impairments and activates mitochondrial biogenesis in a rat model of spinal cord injury

Spinal cord injury (SCI), a multifactorial disease, can lead to irreversible motor and sensory disabilities. Cell therapy in combination with pharmacological agents can be a promising approach to attenuate SCI damages. Epidermal neural crest stem cells (EPI-NCSCs) extracted from bulge hair follicle in adults are attractive candidates due to the possibility of autologous transplantation. This study evaluated the effect of EPI-NCSCs combined with astaxanthin (Ast), a potent antioxidant, on damages induced by SCI. Male rats were treated with Ast (0.2 mM) and EPI-NCSCs (10⁶/10 μl PBS) alone and combined together after SCI contusion. Motor function was assessed by Basso, Beattie and Bresnahan (BBB) test on days 1, 3, 7, 14, 21, 28, 35 and 42 post-injury. Motor neurons number and myelin level were evaluated on days 14 and 42 using Nissl and Luxol Fast Blue staining. The gene expression of mitochondrial biogenesis involved factors (PGC1α, NRF1 and TFAM) was measured by qPCR. All treatments improved motor function, with the highest BBB score in Ast + Cell compared to Ast and Cell. Decreased motor neurons number and myelin level following SCI, were increased by Ast, Cell and Ast + Cell, but combination therapy significantly had a better effect. We observed reduction in PGC1α, NRF1, and TFAM expression in spinal tissue after SCI, and treatment with Cell and Ast + Cell significantly restored NRF1 and TFAM mRNA levels. These results suggested that Ast in combination with EPI-NCSCs has better effects on behavioral dysfunction, motor neuron loss and demyelination after SCI. These protective effects may be attributed to mitochondrial biogenesis activation.

Co-transplantation of Epidermal Neural Crest Stem Cells and Olfactory Ensheathing Cells Repairs Sciatic Nerve Defects in Rats

Cell-based therapy is an alternative strategy to improve outcomes of peripheral nerve injury (PNI). Epidermal neural crest stem cell (EPI-NCSC) is obtained from autologous tissue without immunological rejection, which could expand quickly in vitro and is suitable candidate for cell-based therapy. Olfactory ensheathing cell (OEC) could secrete multiple neurotrophic factors (NTFs), which is often used to repair PNI individually. However, whether the combination of EPI-NCSC and OEC have better effects on PNI repair remains unclear. Here we use EPI-NCSC and OEC co-transplantation in a rat sciatic nerve defect model to ascertain the effects and potential mechanisms of cells co-transplantation on PNI. The effect of EPI-NCSC and OEC co-transplantation on PNI is assessed by using a combination of immunohistochemistry (IHC), electrophysiological recording and neural function test. Co-transplantation of EPI-NCSC and OEC exerts a beneficial effect upon PNI such as better organized structure, nerve function recovery, and lower motoneuron apoptosis. IHC and enzyme-linked immuno sorbent assay (ELISA) further demonstrate that cells co-transplantation may improve PNI via the expression of brain derived growth factor (BDNF) and nerve growth factor (NGF) up-regulated by EPI-NCSC and OEC synergistically. Eventually, the results from this study reveal that EPI-NCSC and OEC co-transplantation effectively repairs PNI through enhancing the level of BDNF and NGF, indicating that cells co-transplantation may serve as a fruitful avenue for PNI in clinic treatment.

Neural stem cell transplantation inhibits glial cell proliferation and P2X receptor-mediated neuropathic pain in spinal cord injury rats

P2X4 and P2X7 receptors play an important role in neuropathic pain after spinal cord injury. Regulation of P2X4 and P2X7 receptors can obviously reduce pain hypersensitivity after injury. To investigate the role of neural stem cell transplantation on P2X receptor-mediated neuropathic pain and explore related mechanisms, a rat model of spinal cord injury was prepared using the free-falling heavy body method with spinal cord segment 10 as the center. Neural stem cells were injected into the injured spinal cord segment using a micro-syringe. Expression levels of P2X4 and P2X7 receptors, neurofilament protein, and glial fibrillary acidic protein were determined by immunohistochemistry and western blot assay. In addition, sensory function was quantitatively assessed by current perception threshold. The Basso-Beattie-Bresnahan locomotor rating scale was used to assess neuropathological pain. The results showed that 4 weeks after neural stem cell transplantation, expression of neurofilament protein in the injured segment was markedly increased, while expression of glial fibrillary acidic protein and P2X4 and P2X7 receptors was decreased. At this time point, motor and sensory functions of rats were obviously improved, and neuropathic pain was alleviated. These findings demonstrated that neural stem cell transplantation reduced overexpression of P2X4 and P2X7 receptors, activated locomotor and sensory function reconstruction, and played an important role in neuropathic pain regulation after spinal cord injury. Therefore, neural stem cell transplantation is one potential option for relieving neuropathic pain mediated by P2X receptors.

Transplantation of olfactory ensheathing cells on functional recovery and neuropathic pain after spinal cord injury; systematic review and meta-analysis

There are considerable disagreements on the application of olfactory ensheathing cells (OEC) for spinal cord injury (SCI) rehabilitation. The present meta-analysis was designed to investigate the efficacy of OEC transplantation on motor function recovery and neuropathic pain alleviation in SCI animal models. Accordingly, all related studies were identified and included. Two independent researchers assessed the quality of the articles and summarized them by calculating standardized mean differences (SMD). OEC transplantation was shown to significantly improve functional recovery (SMD = 1.36; 95% confidence interval: 1.05–1.68; p < 0.001). The efficacy of this method was higher in thoracic injuries (SMD = 1.41; 95% confidence interval: 1.08–1.74; p < 0.001) and allogeneic transplants (SMD = 1.53; 95% confidence interval: 1.15–1.90; p < 0.001). OEC transplantation had no considerable effects on the improvement of hyperalgesia (SMD = −0.095; 95% confidence interval: −0.42–0.23; p = 0.57) but when the analyses were limited to studies with follow-up ≥8 weeks, it was associated with increased hyperalgesia (SMD = −0.66; 95% confidence interval: −1.28–0.04; p = 0.04). OEC transplantation did not affect SCI-induced allodynia (SMD = 0.54; 95% confidence interval: −0.80–1.87; p = 0.43). Our findings showed that OEC transplantation can significantly improve motor function post-SCI, but it has no effect on allodynia and might lead to relative aggravation of hyperalgesia.

Knockdown of Nogo gene by short hairpin RNA interference promotes functional recovery of spinal cord injury in a rat model

The specific myelin component Nogo protein is one of the major inhibitory molecules of spinal cord axonal outgrowth following spinal cord injury. The present study aimed to investigate the effects of silencing Nogo protein with shRNA interference on the promotion of functional recovery in a rat model with spinal cord hemisection. Nogo-A short hairpin RNAs (Nogo shRNAs) were constructed and transfected into rats with spinal cord hemisection by adenovirus-mediated transfection. Reverse transcription‑polymerase chain reaction and western blotting were performed to analyze the expression of Nogo-A and Growth Associated Protein 43 (GAP-43). In addition, Basso Beattie Bresnahan (BBB) scores were used to assess the functional recovery of rats following spinal cord injury. The results demonstrated that expression of the Nogo‑A gene was observed to be downregulated following transfection and GAP‑43 expression was observed to increase. The BBB scores were increased following treatment with Nogo shRNAs, indicating functional recovery of the injured nerves. Thus, Nogo-A shRNA interference can knockdown Nogo gene expression and upregulate GAP-43 to promote the functional recovery of spinal cord injury in rats. This finding may advance progress toward assisting the regeneration of injured neurons through the use of Nogo-A shRNA.