Spinal Cord Injury: Pathophysiology, Multimolecular Interactions, and Underlying Recovery Mechanisms

Pyroptosis in neurodegenerative diseases: from bench to bedside

The central nervous system regulates all aspects of physiology to some extent. Neurodegenerative diseases (NDDs) lead to the progressive loss and dysfunction of neurons, which are particularly evident in Alzheimer's disease, Parkinson's disease, and many other conditions. NDDs are multifactorial diseases with complex pathogeneses, and there has been a rapid increase in the prevalence of NDDs. However, none of these diseases can be cured, making the development of novel treatment strategies an urgent necessity. Numerous studies have indicated how pyroptosis induces inflammation and affects many aspects of NDD. Therefore, components related to pyroptosis are potential therapeutic candidates and are attracting increasing attention. Here, we review the role of pyroptosis in the pathogenesis of NDDs and potential treatment options. Additionally, several of the current drugs and relevant inhibitors are discussed. Through this article, we provide theoretical support for exploring new therapeutic targets and updating clinical treatment strategies for NDDs. Notably, pyroptosis, a recently widely studied mode of cell death, is still under-researched compared to other traditional forms of cell death. Moreover, the focus of research has been on the onset and progression of NDDs, and the lack of organ-specific target discovery and drug development is a common problem for many basic studies. This urgent problem requires scientists and companies worldwide to collaborate in order to develop more effective drugs against NDDs.

Photobiomodulation reduces neuropathic pain after spinal cord injury by downregulating CXCL10 expression

BACKGROUND

Many studies have recently highlighted the role of photobiomodulation (PBM) in neuropathic pain (NP) relief after spinal cord injury (SCI), suggesting that it may be an effective way to relieve NP after SCI. However, the underlying mechanisms remain unclear. This study aimed to determine the potential mechanisms of PBM in NP relief after SCI.

METHODS

We performed systematic observations and investigated the mechanism of PBM intervention in NP in rats after SCI. Using transcriptome sequencing, we screened CXCL10 as a possible target molecule for PBM intervention and validated the results in rat tissues using reverse transcription-polymerase chain reaction and western blotting. Using immunofluorescence co-labeling, astrocytes and microglia were identified as the cells responsible for CXCL10 expression. The involvement of the NF-κB pathway in CXCL10 expression was verified using inhibitor pyrrolidine dithiocarbamate (PDTC) and agonist phorbol-12-myristate-13-acetate (PMA), which were further validated by an in vivo injection experiment.

RESULTS

Here, we demonstrated that PBM therapy led to an improvement in NP relative behaviors post-SCI, inhibited the activation of microglia and astrocytes, and decreased the expression level of CXCL10 in glial cells, which was accompanied by mediation of the NF-κB signaling pathway. Photobiomodulation inhibit the activation of the NF-κB pathway and reduce downstream CXCL10 expression. The NF-κB pathway inhibitor PDTC had the same effect as PBM on improving pain in animals with SCI, and the NF-κB pathway promoter PMA could reverse the beneficial effect of PBM.

CONCLUSIONS

Our results provide new insights into the mechanisms by which PBM alleviates NP after SCI. We demonstrated that PBM significantly inhibited the activation of microglia and astrocytes and decreased the expression level of CXCL10. These effects appear to be related to the NF-κB signaling pathway. Taken together, our study provides evidence that PBM could be a potentially effective therapy for NP after SCI, CXCL10 and NF-kB signaling pathways might be critical factors in pain relief mediated by PBM after SCI.

Temporal profiling and validation of oxidative stress-related genes in spinal cord injury

Oxidative stress (OS) plays a pivotal role in the pathogenesis of spinal cord injury (SCI), yet its underlying mechanisms remain elusive. In this study, we explored the OS phenotype in a rat model of SCI. Subsequently, comprehensive bioinformatic analyses were conducted on microarray data pertaining to SCI (GSE45006). Notably, KEGG enrichment analysis revealed a pronounced enrichment of pivotal pathways, namely MAPK, FoxO, Apoptosis, NF-κB, TNF, HIF-1, and Chemokine across distinct phases of SCI. Furthermore, GO enrichment analysis highlighted the significance of biological processes including response to hypoxia, response to decrease oxygen levels, response to reactive oxygen species, cellular response to oxidative stress, reactive oxygen species metabolic process, and regulation of neuron death in the context of OS following SCI. Notably, our study underscores the prominence of nine genes, namely Itgb1, Itgam, Fn1, Icam1, Cd44, Cxcr4, Ptprc, Tlr4, and Tlr2 as OS key genes in SCI, consistently expressed in both the acute phase (1, 3, 7 days) and sub-acute phase (14 days). Subsequently, the relative mRNA expression of these key genes in different time points (1, 3, 7, 14 days) post-SCI. Finally, leveraging the DsigDB database, we predicted ten potential compounds potentially targeting OS and facilitating the repair of SCI, thus providing novel insights into the mechanisms underlying OS and identifying potential therapeutic targets for SCI.

Phase 1 safety, tolerability, pharmacokinetics and pharmacodynamic results of KCL-286, a novel retinoic acid receptor-β agonist for treatment of spinal cord injury, in male healthy participants

AIMS

KCL-286 is an orally available agonist that activates the retinoic acid receptor (RAR) β2, a transcription factor which stimulates axonal outgrowth. The investigational medicinal product is being developed for treatment of spinal cord injury (SCI). This adaptive dose escalation study evaluated the tolerability, safety and pharmacokinetics and pharmacodynamic activity of KCL-286 in male healthy volunteers to establish dosing to be used in the SCI patient population.

METHODS

The design was a double blind, randomized, placebo-controlled dose escalation study in 2 parts: a single ascending dose adaptive design with a food interaction arm, and a multiple ascending dose design. RARβ2 mRNA expression was evaluated in white blood cells.

RESULTS

At the highest single and multiple ascending doses (100 mg), no trends or clinically important differences were noted in the incidence or intensity of adverse events (AEs), serious AEs or other safety assessments with none leading to withdrawal from the study. The AEs were dry skin, rash, skin exfoliation, raised liver enzymes and eye disorders. There was an increase in mean maximum observed concentration and area under the plasma concentration-time curve up to 24 h showing a trend to subproportionality with dose. RARβ2 was upregulated by the investigational medicinal product in white blood cells.

CONCLUSION

KCL-286 was well tolerated by healthy human participants following doses that exceeded potentially clinically relevant plasma exposures based on preclinical in vivo models. Target engagement shows the drug candidate activates its receptor. These findings support further development of KCL-286 as a novel oral treatment for SCI.

Progress of research into the pharmacological effect and clinical application of the traditional Chinese medicine Rehmanniae Radix

The traditional Chinese medicine (TCM) Rehmanniae Radix (RR) refers to the fresh or dried root tuber of the plant Rehmannia glutinosa Libosch of the family Scrophulariaceae. As a traditional Chinese herbal medicine (CHM), it possesses multiple effects, including analgesia, sedation, anti-inflammation, antioxidation, anti-tumor, immunomodulation, cardiovascular and cerebrovascular regulation, and nerve damage repair, and it has been widely used in clinical practice. In recent years, scientists have extensively studied the active components and pharmacological effects of RR. Active ingredients mainly include iridoid glycosides (such as catalpol and aucuboside), phenylpropanoid glycosides (such as acteoside), other saccharides, and unsaturated fatty acids. In addition, the Chinese patent medicine (CPM) and Chinese decoction related to RR have also become major research subjects for TCM practitioners; one example is the Bolus of Six Drugs, which includes Rehmannia, Lily Bulb and Rehmannia Decoction, and Siwu Decoction. This article reviews recent literature on RR; summarizes the studies on its chemical constituents, pharmacological effects, and clinical applications; and analyzes the progress and limitations of current investigations to provide reference for further exploration and development of RR.

Catalytic antioxidant nanoparticles mitigate secondary injury progression and promote functional recovery in spinal cord injury model

Traumatic spinal cord injury exacerbates disability with time due to secondary injury cascade triggered largely by overproduction of reactive oxygen species (ROS) at the lesion site, causing oxidative stress. This study explored nanoparticles containing antioxidant enzymes (antioxidant NPs) to neutralize excess ROS at the lesion site and its impact. When tested in a rat contusion model of spinal cord injury, a single dose of antioxidant NPs, administered intravenously three hours after injury, effectively restored the redox balance at the lesion site, interrupting the secondary injury progression. This led to reduced spinal cord tissue inflammation, apoptosis, cavitation, and inhibition of syringomyelia. Moreover, the treatment reduced scar tissue forming collagen at the lesion site, protected axons from demyelination, and stimulated lesion healing, with further analysis indicating the formation of immature neurons. The ultimate effect of the treatment was improved motor and sensory functions and rapid post-injury weight loss recovery. Histological analysis revealed activated microglia in the spinal cord displaying rod-shaped anti-inflammatory and regenerative phenotype in treated animals, contrasting with amoeboid inflammatory and degenerative phenotype in untreated control. Overall data suggest that restoring redox balance at the lesion site shifts the dynamics in the injured spinal cord microenvironment from degenerative to regenerative, potentially by promoting endogenous repair mechanisms. Antioxidant NPs show promise to be developed as an early therapeutic intervention in stabilizing injured spinal cord for enhanced recovery.

Extracellular Vesicles: Therapeutic Potential in Central Nervous System Trauma by Regulating Cell Death

CNS (central nervous system) trauma, which is classified as SCI (spinal cord injury) and TBI (traumatic brain injury), is gradually becoming a major cause of accidental death and disability worldwide. Many previous studies have verified that the pathophysiological mechanism underlying cell death and the subsequent neuroinflammation caused by cell death are pivotal factors in the progression of CNS trauma. Simultaneously, EVs (extracellular vesicles), membrane-enclosed particles produced by almost all cell types, have been proven to mediate cell-to-cell communication, and cell death involves complex interactions among molecules. EVs have also been proven to be effective carriers of loaded bioactive components to areas of CNS trauma. Therefore, EVs are promising therapeutic targets to cure CNS trauma. However, the link between EVs and various types of cell death in the context of CNS trauma remains unknown. Therefore, in this review, we summarize the mechanism underlying EV effects, the relationship between EVs and cell death and the pathophysiology underlying EV effects on the CNS trauma based on information in published papers. In addition, we discuss the prospects of applying EVs to the CNS as feasible therapeutic strategies for CNS trauma in the future.

TRIM32 Inhibits NEK7 Ubiquitylation-Dependent Microglia Pyroptosis After Spinal Cord Injury

Spinal cord injury (SCI) is a disabling disease associated with microglial activation. Tripartite motif containing 32 (TRIM32) is an E3 ubiquitin ligase that plays a role in SCI. This study aimed to explore the role of TRIM32 in SCI and its potential mechanisms. We established an SCI mouse model to assess the function of TRIM32 using quantitative real-time polymerase chain reaction (qPCR), and hematoxylin and eosin staining. Additionally, a lipopolysaccharides (LPS)-induced cell injury model was generated to explore the impact of TRIM32 on pyroptosis using qPCR, propidium iodide staining, and western blotting. The ubiquitylation of NEK7 was analyzed using western blotting, co-immunoprecipitation, and immunofluorescence staining. The results showed that TRIM32 expression was increased in SCI mice and LPS-induced BV-2 cells. Overexpression of TRIM32 ameliorated SCI in mice and suppressed pyroptosis in LPS-treated BV-2 cells. Additionally, the E3 ligase TRIM32 promoted the ubiquitylation of NEK7 at the K64 site, leading to the downregulation of NEK7 levels. Inhibiting NEK7 ubiquitylation reversed the suppression of pyroptosis by TRIM32. In conclusion, TRIM32 inhibits microglia pyroptosis by facilitating the ubiquitylation of NEK7 at the K64 site, thereby alleviating the progression of SCI. The findings suggest that TRIM32 has the potential to be a therapeutic target of SCI.

Osteopontin enhances the effect of treadmill training and promotes functional recovery after spinal cord injury

In this study, we examined the combined impact of osteopontin (OPN) and treadmill training on mice with spinal cord injury (SCI). OPN was overexpressed by injecting AAV9-SPP1-GFP into the sensorimotor cortex, followed by a left incomplete C5 crush injury two weeks later. Mice (Ex or Ex + OPN group) were trained at 50% maximum running speed for 8 weeks. To analyze the effects, we used biotinylated dextran amine (BDA) for tracing the corticospinal tract (CST) and performed Western blotting and immunohistochemical methods to assess the activation of the mammalian target of rapamycin (mTOR). We also examined axonal regeneration and conducted behavioral tests to measure functional recovery. The results demonstrated that treadmill training promoted the expression of neurotrophic factors such as brain-derived neurotrophic factor (BNDF) and insulin-like growth factor I (IGF-1) and activated mTOR signaling. OPN amplified the effect of treadmill training on activating mTOR signaling indicated by upregulated phosphorylation of ribosomal protein S6 kinase (S6). The combination of OPN and exercise further promoted functional recovery and facilitated limited CST axonal regeneration which did not occur with treadmill training and OPN treatment alone. These findings indicate that OPN enhances the effects of treadmill training in the treatment of SCI and offer new therapeutic insights for spinal cord injury.

Micro electrical fields induced MSC-sEVs attenuate neuronal cell apoptosis by activating autophagy via lncRNA MALAT1/miR-22-3p/SIRT1/AMPK axis in spinal cord injury

Spinal cord injury (SCI) is a traumatic condition of the central nervous system that causes paralysis of the limbs. Micro electric fields (EF) have been implicated in a novel therapeutic approach for nerve injury repair and regeneration, but the effects of human umbilical cord mesenchymal stem cell-derived small extracellular vesicles that are induced by micro electric fields (EF-sEVs) stimulation on SCI remain unknown. The aim of the present study was to investigate whether EF-sEVs have therapeutic effects a rat model of SCI. EF-sEVs and normally conditioned human umbilical cord mesenchymal stem cells-derived small extracellular vesicles (CON-sEVs) were collected and injected intralesionally into SCI model rats to evaluate the therapeutic effects. We detect the expression of candidate long noncoding RNA metastasis-associated lung adenocarcinoma transcript 1 (lncRNA-MALAT1) in EF-sEVs and CON-sEVs. The targets and downstream effectors of lncRNA-MALAT1 were investigated using luciferase reporter assays. Using both in vivo and in vitro experiments, we demonstrated that EF-sEVs increased autophagy and decreased apoptosis after SCI, which promoted the recovery of motor function. We further confirmed that the neuroprotective effects of EF-sEVs in vitro and in vivo correlated with the presence of encapsulated lncRNA-MALAT1 in sEVs. lncRNA-MALAT1 targeted miR-22-3p via sponging, reducing miR-22-3p's suppressive effects on its target, SIRT1, and this translated into AMPK phosphorylation and increased levels of the antiapoptotic protein Bcl-2. Collectively, the present study identified that the lncRNA-MALAT1 in EF-sEVs plays a neuroprotective role via the miRNA-22-3p/SIRT1/AMPK axis and offers a fresh perspective and a potential therapeutic approach using sEVs to improve SCI.

Recent advances in nanoantibiotics against multidrug-resistant bacteria

Multidrug-resistant (MDR) bacteria-caused infections have been a major threat to human health. The abuse of conventional antibiotics accelerates the generation of MDR bacteria and makes the situation worse. The emergence of nanomaterials holds great promise for solving this tricky problem due to their multiple antibacterial mechanisms, tunable antibacterial spectra, and low probabilities of inducing drug resistance. In this review, we summarize the mechanism of the generation of drug resistance, and introduce the recently developed nanomaterials for dealing with MDR bacteria via various antibacterial mechanisms. Considering that biosafety and mass production are the major bottlenecks hurdling the commercialization of nanoantibiotics, we introduce the related development in these two aspects. We discuss urgent challenges in this field and future perspectives to promote the development and translation of nanoantibiotics as alternatives against MDR pathogens to traditional antibiotics-based approaches.

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.

Hyperbaric Oxygen Therapy Inhibits Neuronal Ferroptosis After Spinal Cord Injury in Mice

STUDY DESIGN

Basic science study investigating the potential molecular mechanisms of hyperbaric oxygen (HBO) therapy in mice with spinal cord injury (SCI).

OBJECTIVE

We aimed to explore the intrinsic mechanisms of HBO for SCI through the lens of ferroptosis in the subacute phase.

SUMMARY OF BACKGROUND DATA

HBO has been observed to facilitate the restoration of neurological function subsequent to SCI. Ferroptosis is a distinct cellular death mechanism that can be distinguished from apoptosis, necrosis, and autophagy. However, the precise relationship between these two phenomena remains poorly understood.

METHODS

We established an SCI model and employed a range of techniques, including behavioral assessments, electron microscopy, immunofluorescence, RT-qPCR, Western blotting (WB), Glutathione (GSH) measurement, and iron assay, to investigate various aspects of HBO therapy on SCI in mice. These included analyzing mitochondrial morphology, neuronal count, GSH levels, iron levels, and the expression of genes (Acyl-CoA synthetase family member-2, Iron-responsive element-binding protein-2) and proteins (Glutathione peroxidase 4; system Xc-light chain) associated with ferroptosis. The study included three groups: Sham-operated, SCI, and HBO. Group comparisons were performed using one-way analysis of variance and one-way repeated measures analysis of variance, followed by Tukey's post hoc test. Statistical significance was set at a P < 0.05.

RESULTS

Our findings revealed that HBO therapy significantly enhanced the recovery of lower limb motor function in mice following SCI in the subacute phase. This was accompanied by upregulated expression of GPX4 and system Xc-light chain proteins, elevated GSH levels, increased number of NeuN+ cells, decreased expression of the iron-responsive element-binding protein-2 gene, and reduced iron concentration.

CONCLUSIONS

Our research suggests that HBO therapy has the potential to be an effective treatment for SCI in the subacute phase by mitigating ferroptosis.

Neuronal NADPH oxidase is required for neurite regeneration of Aplysia bag cell neurons

NADPH oxidase (Nox), a major source of reactive oxygen species (ROS), is involved in neurodegeneration after injury and disease. Nox is expressed in both neuronal and non-neuronal cells and contributes to an elevated ROS level after injury. Contrary to the well-known damaging effect of Nox-derived ROS in neurodegeneration, recently a physiological role of Nox in nervous system development including neurogenesis, neuronal polarity, and axonal growth has been revealed. Here, we tested a role for neuronal Nox in neurite regeneration following mechanical transection in cultured Aplysia bag cell neurons. Using a novel hydrogen peroxide (H2 O2 )-sensing dye, 5'-(p-borophenyl)-2'-pyridylthiazole pinacol ester (BPPT), we found that H2 O2 levels are elevated in regenerating growth cones following injury. Redistribution of Nox2 and p40phox in the growth cone central domain suggests Nox2 activation after injury. Inhibiting Nox with the pan-Nox inhibitor celastrol reduced neurite regeneration rate. Pharmacological inhibition of Nox is correlated with reduced activation of Src2 tyrosine kinase and F-actin content in the growth cone. Taken together, these findings suggest that Nox-derived ROS regulate neurite regeneration following injury through Src2-mediated regulation of actin organization in Aplysia growth cones.

Mesenchymal stem cell attenuates spinal cord injury by inhibiting mitochondrial quality control-associated neuronal ferroptosis

Ferroptosis is a newly discovered form of iron-dependent oxidative cell death and drives the loss of neurons in spinal cord injury (SCI). Mitochondrial damage is a critical contributor to neuronal death, while mitochondrial quality control (MQC) is an essential process for maintaining mitochondrial homeostasis to promote neuronal survival. However, the role of MQC in neuronal ferroptosis has not been clearly elucidated. Here, we further demonstrate that neurons primarily suffer from ferroptosis in SCI at the single-cell RNA sequencing level. Mechanistically, disordered MQC aggravates ferroptosis through excessive mitochondrial fission and mitophagy. Furthermore, mesenchymal stem cells (MSCs)-mediated mitochondrial transfer restores neuronal mitochondria pool and inhibits ferroptosis through mitochondrial fusion by intercellular tunneling nanotubes. Collectively, these results not only suggest that neuronal ferroptosis is regulated in an MQC-dependent manner, but also fulfill the molecular mechanism by which MSCs attenuate neuronal ferroptosis at the subcellular organelle level. More importantly, it provides a promising clinical translation strategy based on stem cell-mediated mitochondrial therapy for mitochondria-related central nervous system disorders.

Syntaphilin Inactivation Can Enhance Axonal Mitochondrial Transport to Improve Spinal Cord Injury

Mitochondria are important organelle of eukaryotic cells. They consists of a large number of different proteins that provide most of the ATP and supply power for the growth, function, and regeneration of neurons. Therefore, smitochondrial transport ensures that adequate ATP is supplied for metabolic activities. Spinal cord injury (SCI), a detrimental condition, has high morbidity and mortality rates. Currently, the available treatments only provide symptomatic relief for long-term disabilities. Studies have implicated mitochondrial transport as a critical factor in axonal regeneration. Hence, enhancing mitochondrial transports could be beneficial for ameliorating SCI. Syntaphilin (Snph) is a mitochondrial docking protein that acts as a "static anchor," and its inhibition enhances mitochondrial transports. Therefore, Snph as a key mediator of mitochondrial transports, may contribute to improving axonal regeneration following SCI. Herein, we examine Snph's biological effects and its relation to mitochondrial pathway. Then, we elaborate on mitochondrial transports after SCI, the possible role of Snph in SCI, and some possible therapeutic approaches by Snph.

FHL2 regulates microglia M1/M2 polarization after spinal cord injury via PARP14-depended STAT1/6 pathway

Neuronal apoptosis and inflammation exacerbate the secondary injury after spinal cord injury (SCI). Four and a half domains 2 (FHL2) is a multifunctional scaffold protein with tissue- and cell-type specific effects on the regulation of inflammation, but its role in SCI remains unclear. The T10 mouse spinal cord contusion model was established, and the mice were immediately injected with lentiviruses carrying FHL2 shRNA after SCI. The results showed that FHL2 expression was increased following SCI, and then gradually decreased. Moreover, FHL2 depletion aggravated functional impairment, neuronal necrosis, and enlarged lesion cavity areas in the injured spinal cord. FHL2 deficiency facilitated neuronal apoptosis by elevating cleaved caspase 3/9 expression, neuroinflammation by regulating microglia polarization, and bone loss. Indeed, FHL2 deficiency increased the secretion of TNF-α and IL-6, M1 microglia polarization, and the activation of STAT1 pathway but decreased the secretion of IL-10 and IL-4, M2 microglia polarization, and the activation of the STAT6 pathway in the spinal cord. In vitro, FHL2 silencing promoted LPS + IFN-γ-induced microglia M1 polarization through activating the STAT1 pathway and alleviated IL-4-induced microglia M2 polarization via inhibiting the STAT6 pathway. FHL2 positively regulated the expression of poly (ADP-ribose) polymerase family member 14 (PARP14) by promoting its transcription. PARP14 overexpression inhibited FHL2 silencing-induced microglia M1 polarization and relieved the inhibitory effect of FHL2 silencing on microglia M2 polarization. Collectively, the study suggests that FHL2 reduces the microglia M1/M2 polarization-mediated inflammation via PARP14-dependent STAT1/6 pathway and thereby improves functional recovery after SCI.

Drug Repurposing for Spinal Cord Injury: Progress Towards Therapeutic Intervention for Primary Factors and Secondary Complications

Spinal cord injury (SCI) encompasses a plethora of complex mechanisms like the involvement of major cell death pathways, neurodegeneration of spinal cord neurons, overexpression of glutaminergic transmission and inflammation cascade, along with different co-morbidities like neuropathic pain, urinary and sexual dysfunction, respiratory and cardiac failures, making it one of the leading causes of morbidity and mortality globally. Corticosteroids such as methylprednisolone and dexamethasone, and non-steroidal anti-inflammatory drugs such as naproxen, aspirin and ibuprofen are the first-line treatment options for SCI, inhibiting primary and secondary progression by preventing inflammation and action of reactive oxygen species. However, they are constrained by a short effective drug administration window and their pharmacological action being limited to symptomatic relief of the secondary effects related to spinal cord injury only. Although post-injury rehabilitation treatments may enable functional recovery, they take a long time to show results. Drug repurposing might be an innovative method for expanding therapy alternatives, utilising drugs that are already approved by various esteemed federal agencies throughout the world. Reutilising a drug molecule to treat SCI can eliminate the need for expensive and lengthy drug discovery processes and pave the way for new therapeutic approaches in SCI. This review summarises marketed drugs that could be repurposed based on their safety and efficacy data. We also discuss their mechanisms of action and provide a list of repurposed drugs under clinical trials for SCI therapy.

Exosomes derived from schwann cells alleviate mitochondrial dysfunction and necroptosis after spinal cord injury via AMPK signaling pathway-mediated mitophagy

Although spinal cord injury (SCI) represents a primary etiology of disability, currently, there are exist limited viable therapies modalities. Acquiring comprehension of the diverse pathways that drive mitochondrial aberration may facilitate the identification of noteworthy targets for ameliorating the deleterious consequences precipitated by SCI. Our objective was to determine the efficiency of exosomes produced from Schwann cells (SCDEs) in protecting against mitochondrial dysfunction. This evaluation was conducted using a rat model of compressed SCI and in vitro experiments involving rat pheochromocytoma cells (PC12) exposed to oxygen-glucose deprivation (OGD). The conducted experiments yielded evidence that SCDEs effectively mitigated oxidative stress (OS) and inflammation subsequent to SCI, while concurrently diminishing necroptosis. Subsequent in vitro inquiry assessed the impact of SCDEs on PC12, with a specific emphasis on mitochondrial functionality, necrotic cell prevalence, and mitophagy. The study findings revealed that SCDEs enhanced mitophagy in PC12 cells, leading to a decrease in the generation of reactive oxygen species (ROS) and inflammatory cytokines (CK) provoked by OGD-induced injury. This, in turn, mitigated mitochondrial dysfunction and necroptosis. Mechanistically, SCDEs facilitated cellular mitophagy through activation of the AMPK signaling pathway. In conclusion, our data strongly support the notion that SCDEs hold considerable promise as a therapeutic approach for managing SCI. Furthermore, our investigation serves to elucidate the pivotal role of AMPK-mediated mitophagy in reducing cell damage, thereby unveiling novel prospects for enhancing neuro-pathological outcomes following SCI.

Function of GSK‑3 signaling in spinal cord injury (Review)

Spinal cord injury (SCI) is a major social problem with a heavy burden on patient physiology and psychology. Glial scar formation and irreversible neuron loss are the two key points during SCI progression. During the acute phase of spinal cord injury, glial scars form, limiting the progression of inflammation. However, in the subacute or chronic phase, glial scarring inhibits axon regeneration. Following spinal cord injury, irreversible loss of neurons leads to further aggravation of spinal cord injury. Several therapies have been developed to improve either glial scar or neuron loss; however, few therapies reach the stage of clinical trials and there are no mainstream therapies for SCI. Exploring the key mechanism of SCI is crucial for finding further treatments. Glycogen synthase kinase-3 (GSK-3) is a widely expressed kinase with important physiological and pathophysiological functions in vivo. Dysfunction of the GSK-3 signaling pathway during SCI has been widely discussed for controlling neurite growth in vitro and in vivo, improving the proliferation and neuronal differentiation of endogenous neural stem cells and functional recovery from spinal cord injury. SCI can decrease the phosphorylated (p)/total (t)-GSK-3β ratio, which leads to an increase in apoptosis, whereas treatment with GSK-3 inhibitors can promote neurogenesis. In addition, several therapies for the treatment of SCI involve signaling pathways associated with GSK-3. Furthermore, signaling pathways associated with GSK-3 also participate in the pathological process of neuropathic pain that remains following SCI. The present review summarized the roles of GSK-3 signaling in SCI to aid in the understanding of GSK-3 signaling during the pathological processes of SCI and to provide evidence for the development of comprehensive treatments.

Lycium barbarum glycopeptide alleviates neuroinflammation in spinal cord injury via modulating docosahexaenoic acid to inhibiting MAPKs/NF-kB and pyroptosis pathways

BACKGROUND

Lycium barbarum polysaccharide (LBP) is an active ingredient extracted from Lycium barbarum that inhibits neuroinflammation, and Lycium barbarum glycopeptide (LbGp) is a glycoprotein with immunological activity that was purified and isolated from LBP. Previous studies have shown that LbGp can regulate the immune microenvironment, but its specific mechanism of action remains unclear.

AIMS

In this study, we aimed to explore the mechanism of action of LbGp in the treatment of spinal cord injury through metabolomics and molecular experiments.

METHODS

SD male rats were randomly assigned to three experimental groups, and after establishing the spinal cord hemisection model, LbGp was administered orally. Spinal cord tissue was sampled on the seventh day after surgery for molecular and metabolomic experiments. In vitro, LbGp was administered to mimic the inflammatory microenvironment by activating microglia, and its mechanism of action in suppressing neuroinflammation was further elaborated using metabolomics and molecular biology techniques such as western blotting and q-PCR.

RESULTS

In vivo and in vitro experiments found that LbGp can improve the inflammatory microenvironment by inhibiting the NF-kB and pyroptosis pathways. Furthermore, LbGp induced the secretion of docosahexaenoic acid (DHA) by microglia, and DHA inhibited neuroinflammation through the MAPK/NF-κB and pyroptosis pathways.

CONCLUSIONS

In summary, we hypothesize that LbGp improves the inflammatory microenvironment by regulating the secretion of DHA by microglia and thereby inhibiting the MAPK/NF-κB and pyroptosis pathways and promoting nerve repair and motor function recovery. This study provides a new direction for the treatment of spinal cord injury and elucidates the potential mechanism of action of LbGp.

Subacute and Chronic Spinal Cord Injury: A Scoping Review of Epigenetics and Secondary Health Conditions

Background

Epigenetics studies the impact of environmental and behavioral factors on stable phenotypic changes; however, the state of the science examining epigenomic mechanisms of regulation related to secondary health conditions (SHCs) and neuroepigenetics in chronic spinal cord injury (SCI) remain markedly underdeveloped.

Objective

This scoping review seeks to understand the state of the science in epigenetics and secondary complications following SCI.

Methods

A literature search was conducted, yielding 277 articles. The inclusion criteria were articles (1) investigating SCI and (2) examining epigenetic regulation as part of the study methodology. A total of 23 articles were selected for final inclusion.

Results

Of the 23 articles 52% focused on histone modification, while 26% focused on DNA methylation. One study had a human sample, while the majority sampled rats and mice. Primarily, studies examined regeneration, with only one study looking at clinically relevant SHC, such as neuropathic pain.

Discussion

The findings of this scoping review offer exciting insights into epigenetic and neuroepigenetic application in SCI research. Several key genes, proteins, and pathways emerged across studies, suggesting the critical role of epigenetic regulation in biological processes. This review reinforced the dearth of studies that leverage epigenetic methods to identify prognostic biomarkers in SHCs. Preclinical models of SCI were genotypically and phenotypically similar, which is not reflective of the heterogeneity found in the clinical population of persons with SCI. There is a need to develop better preclinical models and more studies that examine the role of genomics and epigenomics in understanding the diverse health outcomes associated with traumatic SCI.

Mesenchymal Stem Cell Transplantation: Neuroprotection and Nerve Regeneration After Spinal Cord Injury

Spinal Cord Injury (SCI), with its morbidity characteristics of high disability rate and high mortality rate, is a disease that is highly destructive to both the physiology and psychology of the patient, and for which there is still a lack of effective treatment. Following spinal cord injury, a cascade of secondary injury reactions known as ischemia, peripheral inflammatory cell infiltration, oxidative stress, etc. create a microenvironment that is unfavorable to neural recovery and ultimately results in apoptosis and necrosis of neurons and glial cells. Mesenchymal stem cell (MSC) transplantation has emerged as a more promising therapeutic options in recent years. MSC can promote spinal cord injury repair through a variety of mechanisms, including immunomodulation, neuroprotection, and nerve regeneration, giving patients with spinal cord injury hope. In this paper, it is discussed the neuroprotection and nerve regeneration components of MSCs' therapeutic method for treating spinal cord injuries.

Poly (ADP-Ribose) polymerase 1 and parthanatos in neurological diseases: From pathogenesis to therapeutic opportunities

Poly (ADP-ribose) polymerase-1 (PARP-1) is the most extensively studied member of the PARP superfamily, with its primary function being the facilitation of DNA damage repair processes. Parthanatos is a type of regulated cell death cascade initiated by PARP-1 hyperactivation, which involves multiple subroutines, including the accumulation of ADP-ribose polymers (PAR), binding of PAR and apoptosis-inducing factor (AIF), release of AIF from the mitochondria, the translocation of the AIF/macrophage migration inhibitory factor (MIF) complex, and massive MIF-mediated DNA fragmentation. Over the past few decades, the role of PARP-1 in central nervous system health and disease has received increasing attention. In this review, we discuss the biological functions of PARP-1 in neural cell proliferation and differentiation, memory formation, brain ageing, and epigenetic regulation. We then elaborate on the involvement of PARP-1 and PARP-1-dependant parthanatos in various neuropathological processes, such as oxidative stress, neuroinflammation, mitochondrial dysfunction, excitotoxicity, autophagy damage, and endoplasmic reticulum (ER) stress. Additional highlight contains PARP-1's implications in the initiation, progression, and therapeutic opportunities for different neurological illnesses, including neurodegenerative diseases, stroke, autism spectrum disorder (ASD), multiple sclerosis (MS), epilepsy, and neuropathic pain (NP). Finally, emerging insights into the repurposing of PARP inhibitors for the management of neurological diseases are provided. This review aims to summarize the exciting advancements in the critical role of PARP-1 in neurological disorders, which may open new avenues for therapeutic options targeting PARP-1 or parthanatos.

Astaxanthin promotes locomotor function recovery and attenuates tissue damage in rats following spinal cord injury: a systematic review and trial sequential analysis

Spinal cord injury (SCI) is a catastrophic condition with few therapeutic options. Astaxanthin (AST), a natural nutritional supplement with powerful antioxidant activities, is finding its new application in the field of SCI. Here, we performed a systematic review to assess the neurological roles of AST in rats following SCI, and assessed the potential for clinical translation. Searches were conducted on PubMed, Embase, Cochrane Library, the Web of Science, China National Knowledge Infrastructure, WanFang data, Vip Journal Integration Platform, and SinoMed databases. Animal studies that evaluated the neurobiological roles of AST in a rat model of SCI were included. A total of 10 articles were included; most of them had moderate-to-high methodological quality, while the overall quality of evidence was not high. Generally, the meta-analyses revealed that rats treated with AST exhibited an increased Basso, Beattie, and Bresnahan (BBB) score compared with the controls, and the weighted mean differences (WMDs) between those two groups showed a gradual upward trend from days 7 (six studies, n = 88, WMD = 2.85, 95% CI = 1.83 to 3.87, p < 0.00001) to days 28 (five studies, n = 76, WMD = 6.42, 95% CI = 4.29 to 8.55, p < 0.00001) after treatment. AST treatment was associated with improved outcomes in spared white matter area, motor neuron survival, and SOD and MDA levels. Subgroup analyses indicated there were differences in the improvement of BBB scores between distinct injury types. The trial sequential analysis then firmly proved that AST could facilitate the locomotor recovery of rats following SCI. In addition, this review suggested that AST could modulate oxidative stress, neuroinflammation, neuron loss, and autophagy via multiple signaling pathways for treating SCI. Collectively, with a protective effect, good safety, and a systematic action mechanism, AST is a promising candidate for future clinical trials of SCI. Nonetheless, in light of the limitations of the included studies, larger and high-quality studies are needed for verification.

Encapsulation of Selenium Nanoparticles and Metformin in Macrophage-Derived Cell Membranes for the Treatment of Spinal Cord Injury

Spinal cord injury is an impact-induced disabling condition. A series of pathological changes after spinal cord injury (SCI) are usually associated with oxidative stress, inflammation, and apoptosis. These pathological changes eventually lead to paralysis. The short half-life and low bioavailability of many drugs also limit the use of many drugs in SCI. In this study, we designed nanovesicles derived from macrophages encapsulating selenium nanoparticles (SeNPs) and metformin (SeNPs-Met-MVs) to be used in the treatment of SCI. These nanovesicles can cross the blood-spinal cord barrier (BSCB) and deliver SeNPs and Met to the site of injury to exert anti-inflammatory and reactive oxygen species scavenging effects. Transmission electron microscopy (TEM) images showed that the SeNPs-Met-MVs particle size was approximately 125 ± 5 nm. Drug release assays showed that Met exhibited sustained release after encapsulation by the macrophage cell membrane. The cumulative release was approximately 80% over 36 h. In vitro cellular experiments and in vivo animal experiments demonstrated that SeNPs-Met-MVs decreased reactive oxygen species (ROS) and malondialdehyde (MDA) levels, increased superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities, and reduced the expression of inflammatory (TNF-α, IL-1β, and IL-6) and apoptotic (cleaved caspase-3) cytokines in spinal cord tissue after SCI. In addition, motor function in mice was significantly improved after SeNPs-Met-MVs treatment. Therefore, SeNPs-Met-MVs have a promising future in the treatment of SCI.

Human Placental Mesenchymal Stem Cell-derived Exosomes in Combination with Hyperbaric Oxygen Synergistically Promote Recovery after Spinal Cord Injury in Rats

Spinal cord injury (SCI) is a critical medical condition during which sensorimotor function is lost. Current treatments are still unable to effectively improve these conditions, so it is important to pay attention to other effective approaches. Currently, we investigated the combined effects of human placenta mesenchymal stem cells (hPMSCs)-derived exosomes along with hyperbaric oxygen (HBO) in the recovery of SCI in rats. Ninety male mature Sprague-Dawley (SD) rats were allocated into five equal groups, including; sham group, SCI group, Exo group (underwent SCI and received hPMSCs-derived exosomes), HBO group (underwent SCI and received HBO), and Exo+HBO group (underwent SCI and received hPMSCs-derived exosomes plus HBO). Tissue samples at the lesion site were obtained for the evaluation of stereological, immunohistochemical, biochemical, molecular, and behavioral characteristics. Findings showed a significant increase in stereological parameters, biochemical factors (GSH, SOD, and CAT), IL-10 gene expression and behavioral functions (BBB and EMG Latency) in treatment groups, especially Exo+HBO group, compared to SCI group. In addition, MDA levels, the density of apoptotic cells and gliosis, as well as expression of inflammatory genes (TNF-α and IL-1β) were considerably reduced in treatment groups, especially Exo+HBO group, compared to SCI group. We conclude that co-administration of hPMSCs-derived exosomes and HBO has synergistic neuroprotective effects in animals undergoing SCI.

Oxidative stress following spinal cord injury: From molecular mechanisms to therapeutic targets

Spinal cord injury (SCI) is a medical condition that results from severe trauma to the central nervous system; it imposes great psychological and economic burdens on affected patients and their families. The dynamic balance between reactive oxygen species (ROS) and antioxidants is essential for maintaining normal cellular physiological functions. As important intracellular signaling molecules, ROS regulate numerous physiological activities, including vascular reactivity and neuronal function. However, excessive ROS can cause damage to cellular macromolecules, including DNA, lipids, and proteins; this damage eventually leads to cell death. This review discusses the mechanisms of oxidative stress in SCI and describes some signaling pathways that regulate oxidative injury after injury, with the aim of providing guidance for the development of novel SCI treatment strategies.

Nissl Granules, Axonal Regeneration, and Regenerative Therapeutics: A Comprehensive Review

Nissl granules, traditionally recognized for their pivotal role in protein synthesis within neuronal cell bodies, are emerging as intriguing components with far-reaching implications in the realm of regenerative therapeutics. This abstract encapsulates the essence of a comprehensive review, exploring the nexus between Nissl granules, axonal regeneration, and their transformative applications in regenerative medicine. The molecular intricacies of Nissl granules form the foundation of this exploration, unraveling their dynamic role in orchestrating cellular responses, particularly in the context of axonal regeneration. As we delve into the interplay between Nissl granules and regenerative processes, this review highlights the diverse mechanisms through which these granules contribute to neuronal repair and recovery. Beyond their conventional association with neurobiology, recent advancements underscore the translational potential of Nissl granules as therapeutic agents. Insights into their involvement in enhancing axonal regeneration prompt a reconsideration of these granules as key players in the broader field of regenerative medicine. The abstract encapsulates evidence suggesting that modulating Nissl granule-related pathways holds promise for augmenting tissue regeneration, extending their applicability beyond the confines of the nervous system. This review aims to serve as a valuable resource for medical professionals, researchers, and clinicians seeking to comprehend the multifaceted role of Nissl granules in regenerative therapeutics. By illuminating the intricate connections between Nissl granules, axonal regeneration, and therapeutic applications, this work aspires to catalyze further research and innovation, ultimately contributing to the evolution of regenerative strategies that harness the innate reparative capacities within cellular constituents.

Zinc defends against Parthanatos and promotes functional recovery after spinal cord injury through SIRT3-mediated anti-oxidative stress and mitophagy

INTRODUCTION

Spinal cord injury (SCI) is a central nervous system injury that is primarily traumatic and manifests as motor, sensory, and autonomic dysfunction below the level of damage. Our previous studies confirmed the ability of zinc to protect mitochondria, protect neurons and promote spinal cord recovery. However, the role of zinc in Parthanatos is unknown.

AIM

We investigated the effects of zinc in Parthanatos from oxidative stress and mitophagy. We elucidated the role of SIRT3 in providing new ideas for treating spinal cord injury.

THE RESULTS

Zinc protected SCI mice by regulating Parthanatos. On the one hand, zinc eliminated ROS directly through SIRT3 deacetylation targeting SOD2 to alleviate Parthanatos. On the other hand, zinc eliminated ROS indirectly through SIRT3-mediated promotion of mitophagy to alleviate Parthanatos.

CONCLUSION

Zinc defends against Parthanatos and promotes functional recovery after spinal cord injury through SIRT3-mediated anti-oxidative stress and mitophagy.

Hyperbaric oxygen therapy and coenzyme Q10 synergistically attenuates damage progression in spinal cord injury in a rat model

BACKGROUND

Identifying effective spinal cord injury (SCI) treatments remains a major challenge, and current approaches are still unable to effectively improve its. Currently, we investigated the combined effects of hyperbaric oxygen (HBO) along with coenzyme Q10 (CoQ10) in the recovery of SCI in rats.

MATERIAL AND METHODS

Ninety female mature Sprague-Dawley rats were allocated into five equal groups, including; sham group, SCI group, HBO group (underwent SCI and received HBO), CoQ10 group (underwent SCI and received CoQ10), and HBO+CoQ10 group (underwent SCI and received HBO plus CoQ10). Tissue samples at the lesion site were obtained for evaluation of stereological, immunohistochemical, biochemical, molecular. Also, functional tests were performed to evaluate of behavioral properties.

RESULTS

We found that a significant increase in stereological parameters, biochemical factors (GSH, SOD and CAT), IL-10 gene expression and behavioral functions (BBB and EMG Latency) in the treatment groups, especially HBO+CoQ10 group, compared to SCI group. In addition, MDA levels, the density of apoptotic cells, as well as expression of inflammatory genes (TNF-α and IL-1β) were considerably reduced in the treatment groups, especially HBO+CoQ10 group, compared to SCI group.

CONCLUSION

We conclude that co-administration of HBO and HBO+CoQ10 has a synergistic neuroprotective effects in animals undergoing SCI.

Stub1 ameliorates ER stress-induced neural cell apoptosis and promotes locomotor recovery through restoring autophagy flux after spinal cord injury

Endoplasmic reticulum (ER) stress-induced apoptosis and autophagy flux blockade significantly contribute to neuronal pathology of spinal cord injury (SCI). Yet, the molecular interplay between these two distinctive pathways in mediating the pathology of SCI remains largely unexplored. Currently, we aimed at exploring the crucial role of Stub1 in maintaining ER homeostasis and regulating autophagic flux after SCI. Our results demonstrate that Stub1 reduces ER stress induced neuronal apoptosis, promotes axonal regeneration, inhibits glial scar formation and fosters functional recovery by restoring autophagic flux following SCI. Stub1 enhances autophagic flux following SCI by alleviating the permeabilization of lysosomal membrane through activating TFEB. Importantly, we showed that Stub1 promotes the activation of TFEB by targeting HDAC2 for ubiquitination and degradation. Furthermore, the neuroprotective effect of Stub1 on SCI was abrogated by chloroquine administration, underscoring the essential role of Stub1-mediated enhancement of autophagic flux in its protective effects against SCI. Collectively, our data highlights the vital role of Stub1 in regulating ER stress and autophagy flux after SCI, and propose its potential as a promising target for neuroprotective interventions in SCI.

In vivo cell fate reprogramming for spinal cord repair

Spinal cord injury (SCI) can lead to the loss of motor, sensory, or autonomic function due to neuronal death. Unfortunately, the adult mammalian spinal cord has limited intrinsic regenerative capacity, making it difficult to rebuild the neural circuits necessary for functional recovery. However, recent evidence suggests that in vivo fate reprogramming of resident cells that are normally non-neurogenic can generate new neurons. This process also improves the pathological microenvironment, and the new neurons can integrate into the local neural network, resulting in better functional outcomes in SCI animal models. In this concise review, we focus on recent advances while also discussing the challenges, pitfalls, and opportunities in the field of in vivo cell fate reprogramming for spinal cord repair.

Effects of Recombinant IL-13 Treatment on Gut Microbiota Composition and Functional Recovery after Hemisection Spinal Cord Injury in Mice

In recent years, the gut-central nervous system axis has emerged as a key factor in the pathophysiology of spinal cord injury (SCI). Interleukin-13 (IL-13) has been shown to have anti-inflammatory and neuroprotective effects in SCI. The aim of this study was to investigate the changes in microbiota composition after hemisection injury and to determine whether systemic recombinant (r)IL-13 treatment could alter the gut microbiome, indirectly promoting functional recovery. The gut microbiota composition was determined by 16S rRNA gene sequencing, and correlations between gut microbiota alterations and functional recovery were assessed. Our results showed that there were no changes in alpha diversity between the groups before and after SCI, while PERMANOVA analysis for beta diversity showed significant differences in fecal microbial communities. Phylogenetic classification of bacterial families revealed a lower abundance of the Bacteroidales S24-7 group and a higher abundance of Lachnospiraceae and Lactobacillaceae in the post-SCI group. Systemic rIL-13 treatment improved functional recovery 28 days post-injury and microbiota analysis revealed increased relative abundance of Clostridiales vadin BB60 and Acetitomaculum and decreased Anaeroplasma, Ruminiclostridium_6, and Ruminococcus compared to controls. Functional assessment with PICRUSt showed that genes related to glyoxylate cycle and palmitoleate biosynthesis-I were the predominant signatures in the rIL-13-treated group, whereas sulfolactate degradation super pathway and formaldehyde assimilation-I were enriched in controls. In conclusion, our results indicate that rIL-13 treatment promotes changes in gut microbial communities and may thereby contribute indirectly to the improvement of functional recovery in mice, possibly having important implications for the development of novel treatment options for SCI.

bFGF-like Activity Supported Tissue Regeneration, Modulated Neuroinflammation, and Rebalanced Ca2+ Homeostasis following Spinal Cord Injury

A spinal cord injury (SCI) is a well-defined debilitating traumatic event to the spinal cord that usually triggers permanent changes in motor, sensory, and autonomic functions. Injured tissue becomes susceptible to secondary mechanisms caused by SCIs, which include pro-inflammatory cytokine release, the activation of astrocytes and microglia, and increased neuronal sensibility. As a consequence, the production of factors such as GFAP, IBA-1, TNF-α, IL-1β, IFN-γ, and S100-β slow down or inhibit central nervous system (CNS) regeneration. In this regard, a thorough understanding of the mechanisms regulating the CNS, and specifically SCI, is essential for the development of new therapeutic strategies. It has been demonstrated that basic fibroblast growth factor (bFGF) was successful in the modulation of neurotrophic activity, also promoting neurite survival and tissue repair, thus resulting in the valuable care of CNS disorders. However, bFGF therapeutic use is limited due to the undesirable effects developed following its administration. Therefore, the synthetic compound mimetic of bFGF, SUN11602 (with chemical name 4-[[4-[[2-[(4-Amino-2,3,5,6-tetramethylphenyl)amino]acetyl]methylamino]-1-piperidinyl]methyl]benzamide), has been reported to show neuroprotective activities similar to those of bFGF, also demonstrating a good pharmacokinetic profile. Here, we aimed to investigate the neuroprotective activity of this bFGF-like compound in modulating tissue regeneration, neuroinflammation, and Ca2+ overload by using a subacute mouse model of SCI. SUN11602 (1, 2.5, and 5 mg/kg) was administered orally to mice for 72 h daily following the in vivo model of SCI, which was generated by the extradural compression of the spinal cord. The data obtained demonstrated that SUN11602 treatment considerably decreased motor alteration and diminished the neuroinflammatory state through the regulation of glial activation, the NF-κB pathway, and kinases. Additionally, by controlling Ca2+-binding proteins and restoring neurotrophin expression, we showed that SUN11602 therapy restored the equilibrium of the neuronal circuit. Because of these findings, bFGF-like compounds may be an effective tool for reducing inflammation in SCI patients while enhancing their quality of life.

Effect of robotic-assisted gait training on gait and motor function in spinal cord injury: a protocol of a systematic review with meta-analysis

INTRODUCTION

Robotic-assisted gait training (RAGT) has been reported to be effective in rehabilitating patients with spinal cord injury (SCI). However, studies on RAGT showed different results due to a varied number of samples. Thus, summarising studies based on robotic-related factors is critical for the accurate estimation of the effects of RAGT on SCI. This work aims to search for strong evidence showing that using RAGT is effective in treating SCI and analyse the deficiencies of current studies.

METHODS AND ANALYSIS

The following publication databases were electronically searched in December 2022 without restrictions on publication year: MEDLINE, Cochrane Library, Web of Science, Embase, PubMed, the Cochrane Central Register of Controlled Trials and China National Knowledge Infrastructure. Various combinations of keywords, including 'motor disorders', 'robotics', 'robotic-assisted gait training', 'Spinal Cord Injuries', 'SCI' and 'gait analysis' were used as search terms. All articles on randomised controlled trials (excluding retrospective trials) using RAGT to treat SCI that were published in English and Chinese and met the inclusion criteria were included. Outcomes included motor function, and gait parameters included those assessed by using the instrumented gait assessment, the Berg Balance Scale, the 10-m walk speed test, the 6-min walk endurance test, the functional ambulation category scale, the Walking index of SCI and the American Spinal Injury Association assessment scale. Research selection, data extraction and quality assessment were conducted independently by two reviewers to ensure that all relevant studies were free from personal bias. In addition, the Cochrane risk-of-bias assessment tool was used to assess the risk of bias. Review Manager V.5.3 software was used to produce deviation risk maps and perform paired meta-analyses.

ETHICS AND DISSEMINATION

Ethics approval is not required for systematic reviews and network meta-analyses. The results will be submitted to a peer-reviewed journal or presented at a conference.

PROSPERO REGISTRATION NUMBER

CRD42022319555.

Effects of comprehensive functional nursing on functional recovery and quality of life in patients with spinal cord injury

This study evaluated the effects of comprehensive functional nursing on functional recovery and quality of life in patients with spinal cord injuries (SCIs). A total of 214 patients with SCIs treated in our hospital from October 2019 to October 2021 were included in the retrospective analysis and divided into a general care group (n = 107) and a comprehensive care group (n = 107), based on the care that they received. Patients in the general care group received general functional nursing, whereas those in the comprehensive care group received a comprehensive functional nursing intervention. The Rivermead Mobility Index (RMI), Barthel Index (BI), and Berg Balance Score (BBS) were used to evaluate patient neurobehavioral ability before and after nursing. Changes in cardiopulmonary function indexes, left ventricular end-diastolic dimension (LVEDD), left ventricular end-systolic dimension (LVESD), vital capacity (VC), forced expiratory volume in 1 second (FEV1), FEV1/FVC, and maximal voluntary ventilation (MVV) were measured before and after nursing. The number of micturition, maximum micturition volume, bladder volume, residual urine volume, and lower urinary tract symptom (LUTS) score were recorded, and the improvement in bladder function were measured before and after nursing. The Hamilton Anxiety Scale (HAMA) and Beck Depression Inventory (BDI) scores were used to evaluate patients' emotional state. After nursing, the RMI, BI, BBS score, FEV1, FEV1/FVC, MVV, maximum micturition volume, bladder volume, and SF-36 scores of the comprehensive care group were significantly higher than those of the general care group, and the LVEDD, LVESD, micturition time, residual urine volume, and LUTS, HAMA, and BDI scores of the comprehensive care group were significantly lower than those of the general care group. In patients with SCIs, comprehensive functional nursing can promote the recovery of neurocognition, bladder function, and cardiorespiratory function, and improve their quality of life. Comprehensive functional nursing is worthy of clinical application.

Role of Stem Cell-Derived Exosomes and microRNAs in Spinal Cord Injury

Neurological disorders represent a global health problem. Current pharmacological treatments often lead to short-term symptomatic relief but have dose-dependent side effects, such as inducing orthostatic arterial hypotension due to the blockade of alpha receptors, cardiotoxic effects due to impaired repolarization, and atrioventricular block and tachycardia, including ventricular fibrillation. These challenges have driven the medical community to seek effective treatments for this serious global health threat. Mesenchymal stem cells (MSCs) are pluripotent cells with anti-inflammatory, anti-apoptotic, and immunomodulatory properties, providing a promising alternative due to their ability to differentiate, favorable culture conditions, in vitro manipulation ability, and robust properties. Although MSCs themselves rarely differentiate into neurons at the site of injury after transplantation in vivo, paracrine factors secreted by MSCs can create environmental conditions for cell-to-cell communication and have shown therapeutic effects. Recent studies have shown that the pleiotropic effects of MSCs, particularly their immunomodulatory potential, can be attributed primarily to these paracrine factors. Exosomes derived from MSCs are known to play an important role in these effects. Many studies have evaluated the potential of exosome-based therapies for the treatment of various neurological diseases. In addition to exosomes, various miRNAs derived from MSCs have been identified to regulate genes and alleviate neuropathological changes in neurodegenerative diseases. This review explores the burgeoning field of exosome-based therapies, focusing on the effects of MSC-derived exosomes and exosomal miRNAs, and summarizes recent findings that shed light on the potential of exosomes in the treatment of neurological disorders. The insights gained from this review may pave the way for innovative and effective treatments for these complex conditions. Furthermore, we suggest the therapeutic effects of exosomes and exosomal miRNAs from MSCs, which have a rescue potential in spinal cord injury via diverse signaling pathways.

Learning Activities of Daily Living from Unobtrusive Multimodal Wearables: Towards Monitoring Outpatient Rehabilitation

Monitoring activities of daily living (ADLs) for wheelchair users, particularly spinal cord injury individuals is important for understanding the rehabilitation progress, customizing treatment plans, and observing the onset of secondary health conditions. This work proposes an innovative sensory system for measuring and classifying ADLs relevant to secondary health conditions. We systematically evaluated multiple wearable sensors such as pressure distribution mats on the wheelchair seat, accelerometer data from the ear and wrists, and IMU data from the wheelchair wheels to achieve the best unobtrusive combination of sensors that successfully distinguished ADLs. Our work resulted in an XGBoost classifier with a 20-second window size and extracted features in statistical, time, frequency, and wavelet domains, with an average class-wise F1 score of 82% (with only 3 out of 12 classes being mislabeled). Our study results demonstrate that the newly investigated modality of the bottom pressure mat emerges as the most relevant information source for recognizing ADLs, while heart and respiratory rates did not provide added value for the selected set of ADLs. The proposed sensory system and methodology proved high quality in most classes and easily extendable for long-term monitoring in outpatient rehabilitation, with the need for an extended database of activities.

Umbilical mesenchymal stem cell-derived exosomes promote spinal cord functional recovery through the miR-146b/TLR4 -mediated NF-κB p65 signaling pathway in rats

Spinal cord injury (SCI) is an incurable central nervous system impairment that lack of efficient treatment. Exosomes derived from mesenchymal stem cells (MSCs) are widely applied in disease treatment. This work aimed to determine the promising therapeutic effects of MSC-derived exosomal miRNA146b on SCI. A rat spinal cord injury (SCI) model and lipopolysaccharide (LPS)-induced PC12 cell model were established. Exosomes were extracted from human umbilical cord mesenchymal stem cells (hUCMSCs). The identification of exosomes was performed by using transmission electronic microscope (TEM) and nanoparticle tracking analysis (NTA). Hematoxylin and eosin (HE) staining and TUNEL assay were performed to assess tissue damage and apoptosis, respectively. ELISA was performed to detect levels of inflammatory cytokines. Cell viability was checked by cell counting kit 8 (CCK-8). Gene expression and protein levels were detected by qPCR and western blotting assay. The interaction between miR-146 b and Toll-like receptor 4 (TLR4) was assessed by luciferase reporter gene assay. The hUCMSC-derived exosomes could notably alleviate the spinal cord injury and cell apoptosis. The exosomal miR-146 b treatment suppressed the release of IL-1 β, IL-6, and TNFα. The miR-146 b suppressed the expression of TLR4, directly interact with the 3'-untranslated region (3'UTR) of TLR4, and inactivated the nuclear factor κB (NF-κB) signaling. The hUCMSCs-derived exosomal miR-146 b protects neurons from spinal cord injury through targeting the TLR4 and inactivating the NF-κB signaling. Our findings supported the application of hUCMSCs-derived exosomal miR-146 b for the protection of SCI.

Does an apple a day keep away diseases? Evidence and mechanism of action

Apples and their products exemplify the recently reemphasized link between dietary fruit intake and the alleviation of human disease. Their consumption does indeed improve human health due to their high phytochemical content. To identify potentially relevant articles from clinical trials, some epidemiological studies and meta-analyses, and in vitro and in vivo studies (cell cultures and animal models), PubMed was searched from January 1, 2012, to May 15, 2022. This review summarized the potential effects of apple and apple products (juices, puree, pomace, dried apples, extracts rich in apple bioactives and single apple bioactives) on health. Apples and apple products have protective effects against cardiovascular diseases, cancer, as well as mild cognitive impairment and promote hair growth, healing of burn wounds, improve the oral environment, prevent niacin-induced skin flushing, promote the relief of UV-induced skin pigmentation, and improve the symptoms of atopic dermatitis as well as cedar hay fever among others. These effects are associated with various mechanisms, such as vascular endothelial protection, blood lipids lowering, anti-inflammatory, antioxidant, antiapoptotic, anti-invasion, and antimetastatic effects. Meanwhile, it has provided an important reference for the application and development of medicine, nutrition, and other fields.

The discovery of the new mechanism: Celastrol improves spinal cord injury by increasing cAMP through VIP-ADCYAP1R1-GNAS pathway

Spinal cord injury (SCI) is a debilitating condition that results in significant impairment of motor function and sensation. Despite the ongoing efforts to develop effective treatments, there are currently very limited options available for patients with SCI. Celastrol, a natural anti-inflammatory compound extracted from Tripterygium wilfordii, has been shown to exhibit anti-inflammatory and anti-apoptotic properties. In this study, we aimed to explore the therapeutic potential of celastrol for SCI and elucidate the underlying molecular mechanisms involved. We found that local tissue often experiences a significant decrease in cAMP content and occurrs apoptosis after SCI. However, the treatment of celastrol could promote the production of cAMP by up-regulating the VIP-ADCYAP1R1-GNAS pathway. This could effectively inhibit the phosphorylation of JNK and prevent apoptosis, ultimately improving the exercise ability after SCI. Together, our results reveal celastrol may be a promising therapeutic agent for the treatment of SCI.

Identification and Validation of Ferroptosis-Related Genes in Patients with Acute Spinal Cord Injury

Ferroptosis plays crucial roles in the pathology of spinal cord injury (SCI). The purpose of this study was to identify differentially expressed ferroptosis-related genes (DE-FRGs) in human acute SCI by bioinformatics analysis and validate the hub DE-FRGs in non-SCI and SCI patients. The GSE151371 dataset was downloaded from the Gene Expression Omnibus and difference analysis was performed. The differentially expressed genes (DEGs) in GSE151371 overlapped with the ferroptosis-related genes (FRGs) obtained from the Ferroptosis Database. A total of 41 DE-FRGs were detected in 38 SCI samples and 10 healthy samples in GSE151371. Then, enrichment analyses of these DE-FRGs were performed for functional annotation. The GO enrichment results showed that upregulated DE-FRGs were mainly associated with reactive oxygen species and redox reactions, and the KEGG enrichment analysis indicated involvement in some diseases and ferroptosis pathways. Protein-protein interaction (PPI) analysis and lncRNA-miRNA-mRNA regulatory network were performed to explore the correlations between genes and regulatory mechanisms. The relationship between DE-FRGs and differentially expressed mitochondria-related genes (DE-MRGs) was also analyzed. Finally, quantitative real-time polymerase chain reaction (qRT-PCR) was used to verify the hub DE-FRGs in clinical blood samples from acute SCI patients and healthy controls. Consistent with the bioinformatics results, qRT-PCR of the clinical samples indicated similar expression levels of TLR4, STAT3, and HMOX1. This study identified DE-FRGs in blood samples from SCI patients, and the results could improve our understanding of the molecular mechanisms of ferroptosis in SCI. These candidate genes and pathways could be therapeutic targets for SCI.

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.

Low-dose lipopolysaccharide inhibits spinal cord injury-induced neuronal apoptosis by regulating autophagy through the lncRNA MALAT1/Nrf2 axis

Background

Spinal cord injury (SCI) is a neurological disease associated with a high disability rate. Low-dose lipopolysaccharide (LPS) has been reported to activate cross-immune tolerance and alleviate the effects of various traumatic stimuli. The present study aimed to explore the effect of LPS on SCI and the potential molecular mechanism.

Methods

Male Sprague-Dawley (SD) rats were used to established an in vivo SCI model and were intraperitoneally injected with lentivirus particles encoding a MALAT1 small interfering RNA (siRNA) on day 10 prior to SCI and with 0.2 mg/kg LPS 72 h prior to SCI. Basso, Beattie, and Bresnahan (BBB) scoring; HE staining; and TUNEL assay were used to assess neurological function and pathophysiological changes. Western blot and immunohistochemistry (IHC) were used to detect cell autophagy and Nrf2 nuclear translocation. PC12 cells were exposed to oxygen-glucose deprivation/reoxygenation (OGD/R) to establish an in vitro SCI model. In vitro SCI model cells were pretreated with LPS and transfected with siMALAT1 or MALAT1 overexpression plasmid aimed at knocking down MALAT1 or overexpressing MALAT1. The cell counting kit-8 (CCK-8) assay was used to measure the toxicity of LPS towards PC12 cells. Flow cytometry and immunofluorescence analysis were performed to investigate cell apoptosis and Nrf2 nuclear translocation.

Results

SCI rats preconditioned with low-dose LPS had higher BBB scores, reduced SCI injury, increased MALAT1 expression and activated autophagy and Nrf2 nuclear translocation in the in vivo SCI model. In the in vitro SCI model, low-dose LPS treatment suppressed the apoptotic ratio of PC12 cells, increased MALAT1 expression, activated autophagy, and promoted Nrf2 nuclear translocation. Silencing MALAT1 exacerbated OGD/R injury in vitro and weakened the protective effect of low-dose LPS. Overexpression of MALAT1 inhibits OGD/R-induced apoptosis by inducing autophagy and promoting Nrf2 nuclear translocation. This was also been confirmed in animal experiments, silencing MALAT1 blocked the promotion of Nrf2 by low-dose LPS and the alleviated of SCI apoptosis.

Conclusions

Low-dose LPS exhibited a protective role on SCI by activating autophagy and suppressing nerve cell apoptosis via the lncRNA MALAT1/Nrf2 axis.

Pediatric Spinal Cord Injury: A Review

A spinal cord injury (SCI) can be a devastating condition in children, with profound implications for their overall health and quality of life. In this review, we aim to provide a concise overview of the key aspects associated with SCIs in the pediatric population. Firstly, we discuss the etiology and epidemiology of SCIs in children, highlighting the diverse range of causes. We explore the unique anatomical and physiological characteristics of the developing spinal cord that contribute to the specific challenges faced by pediatric patients. Next, we delve into the clinical presentation and diagnostic methods, emphasizing the importance of prompt and accurate diagnosis to facilitate appropriate interventions. Furthermore, we approach the multidisciplinary management of pediatric SCIs, encompassing acute medical care, surgical interventions, and ongoing supportive therapies. Finally, we explore emerging research as well as innovative therapies in the field, and we emphasize the need for continued advancements in understanding and treating SCIs in children to improve their functional independence and overall quality of life.

Melatonin, a natural antioxidant therapy in spinal cord injury

Spinal cord injury (SCI) is a sudden onset of disruption to the spinal neural tissue, leading to loss of motor control and sensory function of the body. Oxidative stress is considered a hallmark in SCI followed by a series of events, including inflammation and cellular apoptosis. Melatonin was originally discovered as a hormone produced by the pineal gland. The subcellular localization of melatonin has been identified in mitochondria, exhibiting specific onsite protection to excess mitochondrial reactive oxygen species and working as an antioxidant in diseases. The recent discovery regarding the molecular basis of ligand selectivity for melatonin receptors and the constant efforts on finding synthetic melatonin alternatives have drawn researchers' attention back to melatonin. This review outlines the application of melatonin in SCI, including 1) the relationship between the melatonin rhythm and SCI in clinic; 2) the neuroprotective role of melatonin in experimental traumatic and ischemia/reperfusion SCI, i.e., exhibiting anti-oxidative, anti-inflammatory, and anti-apoptosis effects, facilitating the integrity of the blood-spinal cord barrier, ameliorating edema, preventing neural death, reducing scar formation, and promoting axon regeneration and neuroplasticity; 3) protecting gut microbiota and peripheral organs; 4) synergizing with drugs, rehabilitation training, stem cell therapy, and biomedical material engineering; and 5) the potential side effects. This comprehensive review provides new insights on melatonin as a natural antioxidant therapy in facilitating rehabilitation in SCI.

A swift expanding trend of extracellular vesicles in spinal cord injury research: a bibliometric analysis

Extracellular vesicles (EVs) in the field of spinal cord injury (SCI) have garnered significant attention for their potential applications in diagnosis and therapy. However, no bibliometric assessment has been conducted to evaluate the scientific progress in this area. A search of articles in Web of Science (WoS) from January 1, 1991, to May 1, 2023, yielded 359 papers that were analyzed using various online analysis tools. These articles have been cited 10,842 times with 30.2 times per paper. The number of publications experienced explosive growth starting in 2015. China and the United States led this research initiative. Keywords were divided into 3 clusters, including "Pathophysiology of SCI", "Bioactive components of EVs", and "Therapeutic effects of EVs in SCI". By integrating the average appearing year (AAY) of keywords in VoSviewer with the time zone map of the Citation Explosion in CiteSpace, the focal point of research has undergone a transformative shift. The emphasis has moved away from pathophysiological factors such as "axon", "vesicle", and "glial cell" to more mechanistic and applied domains such as "activation", "pathways", "hydrogels" and "therapy". In conclusions, institutions are expected to allocate more resources towards EVs-loaded hydrogel therapy and the utilization of innovative materials for injury mitigation.

Huntingtin-associated protein 1 ameliorates neurological function rehabilitation by facilitating neurite elongation through TrKA-MAPK pathway in mice spinal cord injury

Aims

Huntingtin-associated protein 1 (HAP1) is a neuronal protein closely associated with microtubules and might facilitate neurological function rehabilitation. This study aimed to investigate the effects of HAP1 on SCI and the underlying mechanisms.

Methods

the spinal cord injury (SCI) mouse model was induced by Allen's method. Then recombinant-HAP1 (r-HAP1) was administrated by intrathecal injection, and the BMS, Thermal nociceptive thresholds, tactile nociceptive thresholds, and neurofibrillary regeneration were identified to inspect the therapy outcome. Then NSCs were isolated from mice on embryonic day 14.5 and induced to differentiate into neurons. The efficiency of axon growth was calculated. Signaling pathway array was conducted to examine the signaling pathways in NSCs treated with r-HAP1. Antagonists and activators of TrkA were used to confirm the role of TrkA of HAP1 intervention both in vitro and in vivo.

Results

r-HAP1 ameliorates the neurological function rehabilitation after SCI, and benefits the regain of Tuj in injury spinal cord. Also significantly enhances neurite growth during neuronal differentiation of NSCs; Signaling pathway array and Western blot revealed that r-HAP1 significantly activates the phosphorylation of TrkA-MAPK/ERK in NSCs. TrkA selective inhibitor GW441756 blocks r-HAP1 on TrkA-MAPK/ERK signaling pathway and detracts from axonal growth after neuronal differentiation. TrkA selective activator gambogic amide can mimic the function of r-HAP1 by activating the foregoing pathway. ERK activator U-46619 reverses the blocking effect of GW441756 on r-HAP1.

Conclusion

HAP1 activates the TrkA-MAPK signaling pathway and is conducive to neurite elongation during NSC neuronal differentiation; by which to improve the prognosis of spinal cord injury in mice.

Porcine Models of Spinal Cord Injury

Large animal models of spinal cord injury may be useful tools in facilitating the development of translational therapies for spinal cord injury (SCI). Porcine models of SCI are of particular interest due to significant anatomic and physiologic similarities to humans. The similar size and functional organization of the porcine spinal cord, for instance, may facilitate more accurate evaluation of axonal regeneration across long distances that more closely resemble the realities of clinical SCI. Furthermore, the porcine cardiovascular system closely resembles that of humans, including at the level of the spinal cord vascular supply. These anatomic and physiologic similarities to humans not only enable more representative SCI models with the ability to accurately evaluate the translational potential of novel therapies, especially biologics, they also facilitate the collection of physiologic data to assess response to therapy in a setting similar to those used in the clinical management of SCI. This review summarizes the current landscape of porcine spinal cord injury research, including the available models, outcome measures, and the strengths, limitations, and alternatives to porcine models. As the number of investigational SCI therapies grow, porcine SCI models provide an attractive platform for the evaluation of promising treatments prior to clinical translation.