Spinal Cord Injury and Related Clinical Trials

Targeted Therapy of Spinal Cord Injury: Inhibition of Apoptosis Is a Promising Therapeutic Strategy

Spinal cord injury (SCI) is a serious disabling central nervous system injury that can lead to motor, sensory, and autonomic dysfunction below the injury level. SCI can be divided into primary injury and secondary injury according to pathological process. Primary injury is mostly irreversible, while secondary injury is a dynamic regulatory process. Apoptosis is an important pathological event of secondary injury and has a significant effect on the recovery of nerve function after SCI. Nerve cell death can further aggravate the microenvironment of the injured site, leading to neurological dysfunction and thus affect the clinical outcome of patients. Therefore, apoptosis plays a crucial role in the pathological progression of secondary SCI, while inhibiting apoptosis may be a promising therapeutic strategy for SCI. This review will summarize and explore the factors that lead to cell death after SCI, the influence of cross talk between signaling pathways and pathways involved in apoptosis and discuss the influence of apoptosis on SCI, and the therapeutic significance of targeting apoptosis on SCI. This review helps us to understand the role of apoptosis in secondary SCI and provides a theoretical basis for the treatment of SCI based on apoptosis.

Combination of induced pluripotent stem cell-derived motor neuron progenitor cells with irradiated brain-derived neurotrophic factor over-expressing engineered mesenchymal stem cells enhanced restoration of axonal regeneration in a chronic spinal cord injury rat model

BACKGROUND

Spinal cord injury (SCI) is a disease that causes permanent impairment of motor, sensory, and autonomic nervous system functions. Stem cell transplantation for neuron regeneration is a promising strategic treatment for SCI. However, selecting stem cell sources and cell transplantation based on experimental evidence is required. Therefore, this study aimed to investigate the efficacy of combination cell transplantation using the brain-derived neurotrophic factor (BDNF) over-expressing engineered mesenchymal stem cell (BDNF-eMSC) and induced pluripotent stem cell-derived motor neuron progenitor cell (iMNP) in a chronic SCI rat model.

METHOD

A contusive chronic SCI was induced in Sprague-Dawley rats. At 6 weeks post-injury, BDNF-eMSC and iMNP were transplanted into the lesion site via the intralesional route. At 12 weeks post-injury, differentiation and growth factors were evaluated through immunofluorescence staining and western blot analysis. Motor neuron differentiation and neurite outgrowth were evaluated by co-culturing BDNF-eMSC and iMNP in vitro in 2-dimensional and 3-dimensional.

RESULTS

Combination cell transplantation in the chronic SCI model improved behavioral recovery more than single-cell transplantation. Additionally, combination cell transplantation enhanced mature motor neuron differentiation and axonal regeneration at the injured spinal cord. Both BDNF-eMSC and iMNP played a critical role in neurite outgrowth and motor neuron maturation via BDNF expression.

CONCLUSIONS

Our results suggest that the combined transplantation of BDNF- eMSC and iMNP in chronic SCI results in a significant clinical recovery. The transplanted iMNP cells predominantly differentiated into mature motor neurons. Additionally, BDNF-eMSC exerts a paracrine effect on neuron regeneration through BDNF expression in the injured spinal cord.

Progress and research trends in neurogenic bladder after spinal cord injury bibliometric analysis based on web of science database: An observational study

Neurogenic bladder (NB) is a significant complication that often occurs after spinal cord injury. It results from urinary dysfunction caused by the injury, disrupting the normal neural control of the bladder and urethra. Symptoms of NB can include urinary frequency, urgency, incontinence, and retention, all of which can greatly impact the quality of life of affected individuals. While there are articles and reviews on NB, fewer specifically address NB following spinal cord injury. This study examined 1095 publications from January 1, 2000, to March 27, 2024, in the Web of Science core database using bibliometric software like VOSviewer, CiteSpace, and Bibliometrics. The analysis revealed an increasing trend in the number of publications, with the United States and China leading in research output. Professor Jeremy B. Myers from the University of Utah had the highest number of publications, while the University of Michigan and the University of Pittsburgh were the institutions with the most publications. The journal Neurourology and Urodynamics had the highest number of articles, and common keywords included management, quality of life, and dysfunction, highlighting key areas of focus for scholars.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Acute spinal cord injury serum biomarkers in human and rat: a scoping systematic review

STUDY DESIGN

Scoping systematic review.

OBJECTIVES

To summarize the available experimental clinical and animal studies for the identification of all CSF and serum-derived biochemical markers in human and rat SCI models.

SETTING

Tehran, Iran.

METHODS

In this scoping article, we systematically reviewed the electronic databases of PubMed, Scopus, WOS, and CENTRAL to retrieve current literature assessing the levels of different biomarkers in human and rat SCI models.

RESULTS

A total of 19,589 articles were retrieved and 6897 duplicated titles were removed. The remaining 12,692 studies were screened by their title/abstract and 12,636 were removed. The remaining 56 were considered for full-text assessment, and 11 papers did not meet the criteria, and finally, 45 studies were included. 26 studies were human observational studies comprising 1630 patients, and 19 articles studied SCI models in rats, including 832 rats. Upon reviewing the literature, we encountered a remarkable heterogeneity in terms of selected biomarkers, timing, and method of measurement, studied models, extent, and mechanism of injury as well as outcome assessment measures.

CONCLUSIONS

The specific expression and distribution patterns of biomarkers in relation to spinal cord injury (SCI) phases, and their varied concentrations over time, suggest that cerebrospinal fluid (CSF) and blood biomarkers are effective measures for assessing the severity of SCI.

Enhanced axon outgrowth of spinal motor neurons in co-culturing with dorsal root ganglions antagonizes the growth inhibitory environment

Introduction

Forming a bridge made of functional axons to span the lesion is essential to reconstruct the motor circuitry following spinal cord injury (SCI). Dorsal root ganglion (DRG) axons are robust in axon growth and have been proved to facilitate the growth of cortical neurons in a process of axon-facilitated axon regeneration. However, whether DRG transplantation affects the axon outgrowth of spinal motor neurons (SMNs) that play crucial roles in motor circuitry remains unclear.

Methods

We investigated the axonal growth patterns of co-cultured DRGs and SMN aggregates (SMNAs) taking advantage of a well-designed 3D-printed in vitro system. Chondroitin sulphate proteoglycans (CSPG) induced inhibitory matrix was introduced to imitate the inhibitory environment following SCI. Axonal lengths of DRG, SMNA or DRG & SMNA cultured on the permissive or CSPG induced inhibitory matrix were measured and compared.

Results

Our results indicated that under the guidance of full axonal connection generated from two opposing populations of DRGs, SMNA axons were growth-enhanced and elongated along the DRG axon bridge to distances that they could not otherwise reach. Quantitatively, the co-culture increased the SMNA axonal length by 32.1 %. Moreover, the CSPG matrix reduced the axonal length of DRGs and SMNAs by 46.2 % and 17.7 %, respectively. This inhibitory effect was antagonized by the co-culture of DRGs and SMNAs. Especially for SMNAs, they extended the axons across the CSPG-coating matrix, reached the lengths close to those of SMNAs cultured on the permissive matrix alone.

Conclusions

This study deepens our understanding of axon-facilitated reconstruction of the motor circuitry. Moreover, the results support SCI treatment utilizing the enhanced outgrowth of axons to restore functional connectivity in SCI patients.

Emergence of taurine as a therapeutic agent for neurological disorders

Taurine is a sulfur-containing, semi-essential amino acid that occurs naturally in the body. It alternates between inflammation and oxidative stress-mediated injury in various disease models. As part of its limiting functions, taurine also modulates endoplasmic reticulum stress, Ca2+ homeostasis, and neuronal activity at the molecular level. Taurine effectively protects against a number of neurological disorders, including stroke, epilepsy, cerebral ischemia, memory dysfunction, and spinal cord injury. Although various therapies are available, effective management of these disorders remains a global challenge. Approximately 30 million people are affected worldwide. The design of taurine formation could lead to potential drugs/supplements for the health maintenance and treatment of central nervous system disorders. The general neuroprotective effects of taurine and the various possible underlying mechanisms are discussed in this review. This article is a good resource for understanding the general effects of taurine on various diseases. Given the strong evidence for the neuropharmacological efficacy of taurine in various experimental paradigms, it is concluded that this molecule should be considered and further investigated as a potential candidate for neurotherapeutics, with emphasis on mechanism and clinical studies to determine efficacy.

The Role of Resveratrol on Spinal Cord Injury: from Bench to Bedside

Spinal cord injury (SCI) is a severe and disabling injury of the central nervous system, with complex pathological mechanisms leading to sensory and motor dysfunction. Pathological processes, such as oxidative stress, inflammatory response, apoptosis, and glial scarring are important factors that aggravate SCI. Therefore, the inhibition of these pathological processes may contribute to the treatment of SCI. Currently, the pathogenesis of SCI remains under investigation as SCI treatment has not progressed considerably. Resveratrol, a natural polyphenol with anti-inflammatory and antioxidant properties, is considered a potential therapeutic drug for various diseases and plays a beneficial role in nerve damage. Preclinical studies have confirmed that signaling pathways are closely related to the pathological processes in SCI, and resveratrol is believed to exert therapeutic effects in SCI by activating the related signaling pathways. Based on current research on the pathways of resveratrol and its role in SCI, resveratrol may be a potentially effective treatment for SCI. This review summarizes the role of resveratrol in promoting the recovery of nerve function by regulating oxidative stress, inflammation, apoptosis, and glial scar formation in SCI through various mechanisms and pathways, as well as the deficiency of resveratrol in SCI research and the current and anticipated research trends of resveratrol. In addition, this review provides a background for further studies on the molecular mechanisms of SCI and the development of potential therapeutic agents. This information could also help clinicians understand the known mechanisms of action of resveratrol and provide better treatment options for patients with SCI.

The NF-κB Pathway: a Focus on Inflammatory Responses in Spinal Cord Injury

Spinal cord injury (SCI) is a type of central nervous system trauma that can lead to severe nerve injury. Inflammatory reaction after injury is an important pathological process leading to secondary injury. Long-term stimulation of inflammation can further deteriorate the microenvironment of the injured site, leading to the deterioration of neural function. Understanding the signaling pathways that regulate responses after SCI, especially inflammatory responses, is critical for the development of new therapeutic targets and approaches. Nuclear transfer factor-κB (NF-κB) has long been recognized as a key factor in regulating inflammatory responses. The NF-κB pathway is closely related to the pathological process of SCI. Inhibition of this pathway can improve the inflammatory microenvironment and promote the recovery of neural function after SCI. Therefore, the NF-κB pathway may be a potential therapeutic target for SCI. This article reviews the mechanism of inflammatory response after SCI and the characteristics of NF-κB pathway, emphasizing the effect of inhibiting NF-κB on the inflammatory response of SCI to provide a theoretical basis for the biological treatment of SCI.

Long-term changes of Th17 and regulatory T cells in peripheral blood of dogs with spinal cord injury after intervertebral disc herniation

BACKGROUND

Intervertebral disc herniation (IVDH) is one of the most common causes of spinal cord injury (SCI) in dogs. As a result of acute SCI, a complex inflammatory response occurs in the spinal cord. Th17 cells (Th17) produce pro-inflammatory cytokines, while regulatory T cells (Treg) have opposite effects producing anti-inflammatory cytokines. Therefore, the aim of this study was to determine whether Th17- and Treg cells are involved in the pathogenesis of SCI or whether cellular changes occur due to coexisting inflammatory diseases. We hypothesized that chronic alterations in the Th17/Treg ratio are associated with a worse outcome after SCI.

METHODS

Twenty-six paretic or plegic dogs with IVDH with and without coexisting inflammatory disease were investigated in the acute stage of the disease and after recovery of SCI. In addition, a healthy control group was included (n = 14). Quantification of Th17 and Treg cells, from peripheral blood samples, was performed by multicolor flow cytometry and IL17 was measured using an enzyme-linked immunosorbent assay (ELISA).

RESULTS

After recovery significantly higher levels of Th17 (p = 0.0265) and Treg cells (p = 0.00025) were detected compared to acute IVDH but Th17/Treg ratio did not differ significantly. Recovered dogs and the control group did not differ significantly from each other. No association between an imbalance in the ratio and neurologic severity or underlying inflammatory diseases was found.

CONCLUSION

This study demonstrated that altered Th17 and Treg levels in peripheral blood are altered in the acute stage of IVDH, preexisting inflammatory diseases seem not to influence these cell populations. Th17 and Treg cells could be considered when evaluating new treatment strategies for SCI.

Enzyme-Mediated Nerve Growth Factor Release from Nanofibers Using Gelatin Microspheres

Spinal cord injury is a complex environment, with many conflicting growth factors present at different times throughout the injury timeline. Delivery of multiple growth factors has received mixed results, highlighting a need to consider the timing of delivery for possibly antagonistic growth factors. Cell-mediated degradation of delivery vehicles for delayed release of growth factors offers an attractive way to exploit the highly active immune response in the spinal cord injury environment. In this study, growth factor-loaded gelatin microspheres (GMS) combined with methacrylated hyaluronic acid (MeHA) were electrospun to create GMS fibers (GMSF) for delayed release of growth factors (GFs). GMS were successfully combined with MeHA while electrospinning, with an average fiber diameter of 365 ± 10 nm and 44% ± 8% fiber alignment. GMSF with nerve growth factor (NGF) was tested on dissociated chick dorsal root ganglia cells. We further tested the effect of M1 macrophage-conditioned media (M1CM) to simulate macrophage invasion after spinal cord injury for cell-mediated degradation. We hypothesized that neurons grown on GMSF with loaded NGF would exhibit longer neurites in M1CM, showing a release of functional NGF, as compared with controls. GMSF in M1CM was significantly different from MeHA in serum-free media (SFM) and M0-conditioned media (M0CM), as well as GMSF in M0CM (p < 0.05). Moreover, GMSF + NGF in all media conditions were significantly different from MeHA in SFM and M0CM (p < 0.05). The goal of this study was to develop a biomaterial system where drug delivery is triggered by immune response, allowing for more control and longer exposure to encapsulated drugs. The spinal cord injury microenvironment is known to have a robust immune response, making this immune-medicated drug release system particularly significant for directed repair.

The pathogenesis of DLD-mediated cuproptosis induced spinal cord injury and its regulation on immune microenvironment

Introduction

Spinal cord injury (SCI) is a severe central nervous system injury that leads to significant sensory and motor impairment. Copper, an essential trace element in the human body, plays a vital role in various biological functions and is strictly regulated by copper chaperones and transporters. Cuproptosis, a novel type of metal ion-induced cell death, is distinct from iron deprivation. Copper deprivation is closely associated with mitochondrial metabolism and mediated by protein fatty acid acylation.

Methods

In this study, we investigated the effects of cuproptosis-related genes (CRGs) on disease progression and the immune microenvironment in acute spinal cord injury (ASCI) patients. We obtained the gene expression profiles of peripheral blood leukocytes from ASCI patients using the Gene Expression Omnibus (GEO) database. We performed differential gene analysis, constructed protein-protein interaction networks, conducted weighted gene co-expression network analysis (WGCNA), and built a risk model.

Results

Our analysis revealed that dihydrolipoamide dehydrogenase (DLD), a regulator of copper toxicity, was significantly associated with ASCI, and DLD expression was significantly upregulated after ASCI. Furthermore, gene ontology (GO) enrichment analysis and gene set variation analysis (GSVA) showed abnormal activation of metabolism-related processes. Immune infiltration analysis indicated a significant decrease in T cell numbers in ASCI patients, while M2 macrophage numbers were significantly increased and positively correlated with DLD expression.

Discussion

In summary, our study demonstrated that DLD affects the ASCI immune microenvironment by promoting copper toxicity, leading to increased peripheral M2 macrophage polarization and systemic immunosuppression. Thus, DLD has potential as a promising biomarker for ASCI, providing a foundation for future clinical interventions.

Blood spinal cord barrier disruption recovers in patients with degenerative cervical myelopathy after surgical decompression: a prospective cohort study

The pathophysiology of degenerative cervical myelopathy (DCM) is characterized by chronic compression-induced damage to the spinal cord leading to secondary harm such as disruption of the blood spinal cord barrier (BSCB). It is therefore the purpose of this study to analyze BSCB disruption in pre- and postoperative DCM patients and to correlate those with the clinical status and postoperative outcome. This prospectively controlled cohort included 50 DCM patients (21 female; 29 male; mean age: 62.9 ± 11.2 years). As neurological healthy controls, 52 (17 female; 35 male; mean age 61.8 ± 17.3 years) patients with thoracic abdominal aortic aneurysm (TAAA) and indication for open surgery were included. All patients underwent a neurological examination and DCM-associated scores (Neck Disability Index, modified Japanese Orthopaedic Association Score) were assessed. To evaluate the BSCB status, blood and cerebrospinal fluid (CSF) samples (lumbar puncture or CSF drainage) were taken preoperatively and in 15 DCM patients postoperatively (4 female; 11 male; mean age: 64.7 ± 11.1 years). Regarding BSCB disruption, CSF and blood serum were examined for albumin, immunoglobulin (Ig) G, IgA and IgM. Quotients for CSF/serum were standardized and calculated according to Reiber diagnostic criteria. Significantly increased preoperative CSF/serum quotients were found in DCM patients as compared to control patients: Albumin_Q (p < .001), IgA_Q (p < .001) and IgG_Q (p < .001). IgM_Q showed no significant difference (T = - 1.15, p = .255). After surgical decompression, neurological symptoms improved in DCM patients, as shown by a significantly higher postoperative mJOA compared to the preoperative score (p = .001). This neurological improvement was accompanied by a significant change in postoperative CSF/serum quotients for Albumin (p = .005) and IgG (p = .004) with a trend of a weak correlation between CSF markers and neurological recovery. This study further substantiates the previous findings, that a BSCB disruption in DCM patients is evident. Interestingly, surgical decompression appears to be accompanied by neurological improvement and a reduction of CSF/serum quotients, implying a BSCB recovery. We found a weak association between BSCB recovery and neurological improvement. A BSCB disruption might be a key pathomechanism in DCM patients, which could be relevant to treatment and clinical recovery.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

DISCUSSION

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

Research progress of hydrogels as delivery systems and scaffolds in the treatment of secondary spinal cord injury

Secondary spinal cord injury (SSCI) is the second stage of spinal cord injury (SCI) and involves vasculature derangement, immune response, inflammatory response, and glial scar formation. Bioactive additives, such as drugs and cells, have been widely used to inhibit the progression of secondary spinal cord injury. However, the delivery and long-term retention of these additives remain a problem to be solved. In recent years, hydrogels have attracted much attention as a popular delivery system for loading cells and drugs for secondary spinal cord injury therapy. After implantation into the site of spinal cord injury, hydrogels can deliver bioactive additives in situ and induce the unidirectional growth of nerve cells as scaffolds. In addition, physical and chemical methods can endow hydrogels with new functions. In this review, we summarize the current state of various hydrogel delivery systems for secondary spinal cord injury treatment. Moreover, functional modifications of these hydrogels for better therapeutic effects are also discussed to provide a comprehensive insight into the application of hydrogels in the treatment of secondary spinal cord injury.

Molecular Characterization and Clinical Characteristics of m5C-Based RNA Methylation in Spinal Cord Injury: Validated by qPCR

Aberrant patterns of 5-methylcytosine (m5C)-based ribonucleic acid (RNA) methylation have critical roles in various human diseases, but their importance in spinal cord injury (SCI) is largely unknown. We explore the expression patterns and potential roles of m5C-based regulators of RNA modification after SCI. We analyzed 16 m5C-based regulators of RNA modification in tissues with SCI and normal rats from the Gene Expression Omnibus database. We constructed a "gene signature" of m5C-based regulators of RNA modification to predict the prognosis of SCI using least absolute shrinkage and selection operator regression and random-forest strategy. We found that the m5C-related genes, deoxyribonucleic acid (DNA) methyltransferase1 (Dnmt1), methyl-CpG binding domain protein 2 (Mbd2), ubiquitin-like with PHD and ring finger domains 1 (Uhrf1), uracil-N-glycosylase (Ung), and zinc finger and BTB(brica-brac, tramtrack, and broad) domain containing 38 (Zbtb38) had high expression, and zinc finger and BTB domain containing 4 (Zbtb4) had low expression in SCI. Analysis of the correlation between the gene sets of m5C-based regulators of RNA modification and immune-cell infiltration and immune response revealed Dnmt1, DNA methyltransferases 3A (Dnmt3a), Mbd2, and Ung to be positive regulators of the immune microenvironment, and Zbtb4 may negatively regulate the immune environment. Then, two molecular subtypes were identified based on 16 m5C-regulated genes. Functional-enrichment analysis of differentially expressed genes between different patterns of m5C-based modification was undertaken. Through the creation of a protein-protein interaction network, we screened 11 hub genes. We demonstrated their importance between SCI group and sham group using real-time reverse transcription-quantitative polymerase chain reaction in rat model. Expression of hub genes did not correlate with mitophagy but was positively correlated with endoplasmic reticulum stress (ERS), which suggested that there may be differences in ERS between different patterns of m5C-based modification. This present study explored and discovered the close link between m5C regulators-related genes and SCI. We also hope our findings may contribute to further mechanistic and therapeutic research on the role of key m5C regulators after SCI.

Design of GSH-Responsive Curcumin Nanomicelles for Oesophageal Cancer Therapy

Oesophageal cancer is a malignant tumor with high morbidity and mortality. Surgical treatment, radiotherapy, and chemotherapy are the most common treatment methods for oesophageal cancer. However, traditional chemotherapy drugs have poor targeting performance and cause serious adverse drug reactions. In this study, a GSH-sensitive material, ATRA-SS-HA, was developed and self-assembled with curcumin, a natural polyphenol antitumor drug, into nanomicelles Cur@ATRA-SS-HA. The micelles had a suitable particle size, excellent drug loading, encapsulation rate, stability, biocompatibility, and stable release behaviour. In the tumor microenvironment, GSH induced disulfide bond rupture in Cur@ATRA-SS-HA and promoted the release of curcumin, improving tumor targeting. Following GSH-induced release, the curcumin IC50 value was significantly lower than that of free curcumin and better than that of 5-FU. In vivo pharmacokinetic experiments showed that the drug-loaded nanomicelles exhibited better metabolic behaviour than free drugs, which greatly increased the blood concentration of curcumin and increased the half-life of the drug. The design of the nanomicelle provides a novel clinical treatment for oesophageal cancer.

Alpha Tocopherol Loaded Polymeric Nanoparticles: Preparation, Characterizations, and In Vitro Assessments Against Oxidative Stress in Spinal Cord Injury Treatment

Spinal cord injury (SCI) is characterized by mechanical injury or trauma to the spinal cord. Currently, SCI treatment requires extremely high doses of neuroprotective agents, which in turn, causes several adverse effects. To overcome these limitations, the present study focuses on delivery of a low but effective dose of a naturally occurring antioxidant, α-tocopherol (α-TP). Calcium alginate nanoparticles (CA-NP) and poly D,L-lactic-co-glycolic acid nanoparticles (PLGA-NP) prepared by ionotropic gelation and solvent evaporation technique had particle size of 21.9 ± 11.19 and 152.4 ± 10.6 nm, respectively. Surface morphology, surface charge, as well as particle size distribution of both nanoparticles were evaluated. Entrapment of α-TP into CA-NP and PLGA-NP quantified by UPLC showed entrapment efficiency of 4.00 ± 1.63% and 76.6 ± 11.4%, respectively. In vitro cytotoxicity profiles on human astrocyte-spinal cord (HA-sp) showed that blank CA-NP at high concentrations reduced the cell viability whereas blank PLGA-NP showed relatively safer cytotoxic profiles. In addition, PLGA nanoparticles encapsulated with α-TP (α-TP-PLGA-NP) in comparison to α-TP alone at high concentrations were less toxic. Pretreatment of HA-sp cells with α-TP-PLGA-NP showed two-fold higher anti-oxidative protection as compared to α-TP alone, when oxidative stress was induced by H₂O₂. In conclusion, CA-NP were found to be unsuitable for treatment of SCI due to their cytotoxicity. Comparatively, α-TP-PLGA-NP were safer and showed high degree of protection against oxidative stress than α-TP alone.

Preclinical Development of a Therapy for Chronic Traumatic Spinal Cord Injury in Rats Using Human Wharton's Jelly Mesenchymal Stromal Cells: Proof of Concept and Regulatory Compliance

(1) Background: the use of Mesenchymal Stromal Cells (MSC) in emerging therapies for spinal cord injury (SCI) hold the potential to improve functional recovery. However, the development of cell-based medicines is challenging and preclinical studies addressing quality, safety and efficacy must be conducted prior to clinical testing; (2) Methods: herein we present (i) the characterization of the quality attributes of MSC from the Wharton’s jelly (WJ) of the umbilical cord, (ii) safety of intrathecal infusion in a 3-month subchronic toxicity assessment study, and (iii) efficacy in a rat SCI model by controlled impaction (100 kdynes) after single (day 7 post-injury) and repeated dose of 1 × 10⁶ MSC,WJ (days 7 and 14 post-injury) with 70-day monitoring by electrophysiological testing, motor function assessment and histology evaluation; (3) Results: no toxicity associated to MSC,WJ infusion was observed. Regarding efficacy, recovery of locomotion was promoted at early time points. Persistence of MSC,WJ was detected early after administration (day 2 post-injection) but not at days 14 and 63 post-injection. (4) Conclusions: the safety profile and signs of efficacy substantiate the suitability of the presented data for inclusion in the Investigational Medicinal Product Dossier for further consideration by the competent Regulatory Authority to proceed with clinical trials.

Established and Emerging Therapies in Acute Spinal Cord Injury

Acute spinal cord injury (SCI) is devastating for patients and their caretakers and has an annual incidence of 20–50 per million people. Following initial assessment with appropriate physical examination and imaging, patients who are deemed surgical candidates should undergo decompression with stabilization. Earlier intervention can improve neurological recovery in the post-operative period while allowing earlier mobilization. Optimized medical management is paramount to improve outcomes. Emerging strategies for managing SCI in the acute period stem from an evolving understanding of the pathophysiology of the injury. General areas of focus include ischemia prevention, reduction of secondary injury due to inflammation, modulation of the cytotoxic and immune response, and promotion of cellular regeneration. In this article, we review established, emerging, and novel experimental therapies. Continued translational research on these methods will improve the feasibility of bench-to-bedside innovations in treating patients with acute SCI.

Neuroprotective Mechanisms of Ginsenoside Rb1 in Central Nervous System Diseases

Panax ginseng and Panax notoginseng, two well-known herbs with enormous medical value in Asian countries, have a long usage history in China for the therapy of some diseases, such as stroke. Ginsenoside Rb1 is one of most important active ingredients in Panax ginseng and Panax notoginseng. In the last two decades, more attention has focused on ginsenoside Rb1 as an antioxidative, anti-apoptotic and anti-inflammatory agent that can protect the nervous system. In the review, we summarize the neuroprotective roles of ginsenoside Rb1 and its potential mechanisms in central nervous system diseases (CNSDs), including neurodegenerative diseases, cerebral ischemia injury, depression and spinal cord injury. In conclusion, ginsenoside Rb1 has a potential neuroprotection due to its inhibition of oxidative stress, apoptosis, neuroinflammation and autophagy in CNSDs and may be a promising candidate agent for clinical therapy of CNSDs in the future.

Ski regulates the inflammatory response of reactive astrocytes induced by oxygen glucose deprivation/reoxygenation (OGD/R) through the NF-κB pathway

Spinal cord injury (SCI) is a common disease of the nervous system, including primary and secondary injuries.Neuronal inflammation after SCI is the most important pathological process of SCI and a chemical barrier to nerve function recovery after injury.Ski, an evolutionarily conserved functional transcriptional regulator protein, is upregulated in reactive astrocytes after SCI and regulates the biological characteristics of astrocytes. However, its role in the glial inflammatory response triggered by reactive astrocytes after spinal cord ischemia and its exact mechanism remains unclear. This study investigated the role and mechanism of Ski in the inflammatory response triggered by reactive astrocytes induced by oxygen and sugar deprivation/reoxygenation (OGD/R) model in vitro. In the ODG/R model, Ski expression was upregulated.In contrast, Ski upregulation was accompanied by increased levels of iNOS, IL-1β, IL-6, TNF-α, and other inflammation-related factors.These results indicated that the inflammatory response triggered by astrocytes was significantly enhanced in OGD/R-stimulated astrocytes. Astrocytes were transfected with Ski specific siRNA to knock out Ski and subsequently attenuate OGD-induced astrocyte-triggered inflammation.Our results also suggest that Ski downregulation downregulates the expression of iNOS, IL-1β, IL-6, and TNF-α in OGD/R-induced reactive astrocytes by inhibiting the activity of the NF-κB signaling pathway. In conclusion, downregulation of Ski can effectively inhibit glial inflammation in SCI by inhibiting the activity of the NF-κB pathway.These findings suggest that Ski is a promising therapeutic target for inflammatory responses after SCI.In conclusion, Ski downregulation can effectively inhibit glial inflammation in SCI by inhibiting the activity of the NF-κB pathway. These findings suggest that Ski might serve as a promising target for the treatment of inflammatory responses after SCI.

Ultrasound stimulation improves inflammatory resolution, neuroprotection, and functional recovery after spinal cord injury

Spinal cord injury (SCI) is associated with limited functional recovery. Despite advances in neuroscience, realistic therapeutic treatments for SCI remain unavailable. In this study, the effects of non-invasive ultrasound (US) treatment on behavior and inflammatory responses were evaluated in a rat model of SCI. Adult female Sprague–Dawley rats were subjected to spinal cord contusion injury. Two different US parameters (SCIU5: 5% and SCIU40: 40% duty cycle) were applied, and their effects on behavioral recovery after SCI were quantified. Tissue and neuronal responses were detected. Immunofluorescence was used to detect inflammatory markers. In the rat model of SCI, motor function was more effectively restored, and the lesion cavity area was smaller in the SCIU5 group. Furthermore, the SCIU5 protocol elicited an anti-inflammatory response at the injury site by reducing degenerative FJC-labeled neurons, macrophage/microglia activation, and infiltration. Thus, the lesion area decreased, and tissue density increased. Meanwhile, the SCIU40 protocol did not improve motor function or induce an anti-inflammatory response at the injury site. The SCIU5 protocol effectively accelerated the rate of improved exercise performance in the rat model while reducing inflammation. Accordingly, appropriate US stimulation may represent a promising treatment modality for SCI with beneficial anti-inflammatory effects.

Multifaceted Roles of cAMP Signaling in the Repair Process of Spinal Cord Injury and Related Combination Treatments

Spinal cord injury (SCI) results in multiple pathophysiological processes, including blood–spinal cord barrier disruption, hemorrhage/ischemia, oxidative stress, neuroinflammation, scar formation, and demyelination. These responses eventually lead to severe tissue destruction and an inhibitory environment for neural regeneration.cAMP signaling is vital for neurite outgrowth and axonal guidance. Stimulating intracellular cAMP activity significantly promotes neuronal survival and axonal regrowth after SCI.However, neuronal cAMP levels in adult CNS are relatively low and will further decrease after injury. Targeting cAMP signaling has become a promising strategy for neural regeneration over the past two decades. Furthermore, studies have revealed that cAMP signaling is involved in the regulation of glial cell function in the microenvironment of SCI, including macrophages/microglia, reactive astrocytes, and oligodendrocytes. cAMP-elevating agents in the post-injury milieu increase the cAMP levels in both neurons and glial cells and facilitate injury repair through the interplay between neurons and glial cells and ultimately contribute to better morphological and functional outcomes. In recent years, combination treatments associated with cAMP signaling have been shown to exert synergistic effects on the recovery of SCI. Agents carried by nanoparticles exhibit increased water solubility and capacity to cross the blood–spinal cord barrier. Implanted bioscaffolds and injected hydrogels are potential carriers to release agents locally to avoid systemic side effects. Cell transplantation may provide permissive matrices to synergize with the cAMP-enhanced growth capacity of neurons. cAMP can also induce the oriented differentiation of transplanted neural stem/progenitor cells into neurons and increase the survival rate of cell grafts. Emerging progress focused on cAMP compartmentation provides researchers with new perspectives to understand the complexity of downstream signaling, which may facilitate the clinical translation of strategies targeting cAMP signaling for SCI repair.

The role of Wnt/mTOR signaling in spinal cord injury

Spinal cord injury (SCI) is the most common disabling spinal injury, a complex pathologic process that can eventually lead to severe neurological dysfunction. The Wnt/mTOR signaling pathway is a pervasive signaling cascade that regulates a wide range of physiological processes during embryonic development, from stem cell pluripotency to cell fate. Numerous studies have reported that Wnt/mTOR signaling pathway plays an important role in neural development, synaptogenesis, neuron growth, differentiation and survival after the central nervous system (CNS) is damaged. Wnt/mTOR also plays an important role in regulating various pathophysiological processes after spinal cord injury (SCI). After SCI, Wnt/mTOR signal regulates the physiological and pathological processes of neural stem cell proliferation and differentiation, neuronal axon regeneration, neuroinflammation and pain through multiple pathways. Due to the characteristics of the Wnt signal in SCI make it a potential therapeutic target of SCI. In this paper, the characteristics of Wnt/mTOR signal, the role of Wnt/mTOR pathway on SCI and related mechanisms are reviewed, and some unsolved problems are discussed. It is hoped to provide reference value for the research field of the role of Wnt/mTOR pathway in SCI, and provide a theoretical basis for biological therapy of SCI.

Hao1 Is Not a Pathogenic Factor for Ectopic Ossifications but Functions to Regulate the TCA Cycle In Vivo

Ossification of the posterior longitudinal ligament (OPLL), a disease characterized by the ectopic ossification of a spinal ligament, promotes neurological disorders associated with spinal canal stenosis. While blocking ectopic ossification is mandatory to prevent OPLL development and progression, the mechanisms underlying the condition remain unknown. Here we show that expression of hydroxyacid oxidase 1 (Hao1), a gene identified in a previous genome-wide association study (GWAS) as an OPLL-associated candidate gene, specifically and significantly decreased in fibroblasts during osteoblast differentiation. We then newly established Hao1-deficient mice by generating Hao1-flox mice and crossing them with CAG-Cre mice to yield global Hao1-knockout (CAG-Cre/Hao1flox/flox; Hao1 KO) animals. Hao1 KO mice were born normally and exhibited no obvious phenotypes, including growth retardation. Moreover, Hao1 KO mice did not exhibit ectopic ossification or calcification. However, urinary levels of some metabolites of the tricarboxylic acid (TCA) cycle were significantly lower in Hao1 KO compared to control mice based on comprehensive metabolomic analysis. Our data indicate that Hao1 loss does not promote ectopic ossification, but rather that Hao1 functions to regulate the TCA cycle in vivo.

METTL14 promotes apoptosis of spinal cord neurons by inducing EEF1A2 m6A methylation in spinal cord injury

Spinal cord injury (SCI) is a devastating traumatic condition. METTL14-mediated m6A modification is associated with SCI. This study was intended to investigate the functional mechanism of RNA methyltransferase METTL14 in spinal cord neuron apoptosis during SCI. The SCI rat model was established, followed by evaluation of pathological conditions, apoptosis, and viability of spinal cord neurons. The neuronal function of primary cultured spinal motoneurons of rats was assessed after hypoxia/reoxygenation treatment. Expressions of EEF1A2, Akt/mTOR pathway-related proteins, inflammatory cytokines, and apoptosis-related proteins were detected. EEF1A2 was weakly expressed and Akt/mTOR pathway was inhibited in SCI rat models. Hypoxia/Reoxygenation decreased the viability of spinal cord neurons, promoted LDH release and neuronal apoptosis. EEF1A2 overexpression promoted the viability of spinal cord neurons, inhibited neuronal apoptosis, and decreased inflammatory cytokine levels. Silencing METTL14 inhibited m6A modification of EEF1A2 and increased EEF1A2 expression while METTL14 overexpression showed reverse results. EEF1A2 overexpression promoted viability and inhibited apoptosis of spinal cord neurons and inflammation by activating the Akt/mTOR pathway. In conclusion, silencing METTL14 repressed apoptosis of spinal cord neurons and attenuated SCI by inhibiting m6A modification of EEF1A2 and activating the Akt/mTOR pathway.

Ski regulates proliferation and migration of reactive astrocytes induced by lipopolysaccharide (LPS) through PI3K/Akt pathway

Spinal cord injury (SCI) is a leading cause of disability and death worldwide. Reactive astrogliosis, a typical feature of SCI, undergoes various molecular and morphological changes and contributes to glial scar formation, which impedes axonal regeneration. Ski is a novel molecule that regulates the biological characteristics of astrocytes after spinal cord injury, but its function and the exact mechanism of its overexpression in reactive astrocyte proliferation and migration after SCI remain unclear. The purpose of this study was to elucidate the effect and mechanism of Ski on the proliferation and migration of reactive astrocytes, and to regulate the spatiotemporal formation of glial scars after SCI. In an in vitro lipopolysaccharide (LPS)-induced astrocyte injury model, the expression of Ski was upregulated in a time-dependent manner in LPS-induced astrocytes, and the upregulation of Ski was accompanied by that of PCNA, CDK4, CyclinD1, and other proliferation-related proteins. Our findings suggest that Ski promotes the proliferation and migration of reactive astrocytes. Next, astrocytes were transfected with a specific lentivirus to cause the overexpression of Ski, which significantly enhanced the proliferation and migration of reactive astrocytes and LPS-induced activation of the PI3K/Akt pathway. The PI3K/Akt pathway inhibitor LY294002 significantly inhibited the proliferation and migration of LPS-induced reactive astrocytes after Ski overexpression. In conclusion, Ski regulates LPS-induced astrocyte proliferation and migration through the PI3K/Akt pathway, making Ski a promising target for strategies to combat glial scarring after SCI.

Biological Functions and Therapeutic Potential of Autophagy in Spinal Cord Injury

Autophagy is an evolutionarily conserved lysosomal degradation pathway that maintains metabolism and homeostasis by eliminating protein aggregates and damaged organelles. Many studies have reported that autophagy plays an important role in spinal cord injury (SCI). However, the spatiotemporal patterns of autophagy activation after traumatic SCI are contradictory. Most studies show that the activation of autophagy and inhibition of apoptosis have neuroprotective effects on traumatic SCI. However, reports demonstrate that autophagy is strongly associated with distal neuronal death and the impaired functional recovery following traumatic SCI. This article introduces SCI pathophysiology, the physiology and mechanism of autophagy, and our current review on its role in traumatic SCI. We also discuss the interaction between autophagy and apoptosis and the therapeutic effect of activating or inhibiting autophagy in promoting functional recovery. Thus, we aim to provide a theoretical basis for the biological therapy of SCI.

The role of aquaporin 4 (AQP4) in spinal cord injury

Aquaporin-4 (AQP-4) is an aquaporin composed of six helical transmembrane domains and two highly conserved ASN-pro-ALA (NPA) motifs. It is strongly expressed in rodent and human spinal cord tissues and plays a key role in the pathological process after SCI. After SCI, edema, glial scarring, and inflammation can accelerate the progression of injury and lead to deterioration of function. Many studies have reported that AQP-4 plays an important role in SCI. In particular, it plays an important role in secondary pathological processes (spinal cord edema, glial scar formation, and inflammatory response) after SCI. Loss of AQP-4 has been associated with reduced spinal edema and improved prognosis after SCI in mice. In addition, downregulation of AQP-4 reduces glial scar formation and the inflammatory response after SCI. There is a consensus from numerous studies that AQP-4 may be a potential target for SCI therapy, which guides the ongoing investigation for molecular therapy of SCI. Here, we review the structure of AQP-4, its expression in normal and damaged spinal cord, and its role in SCI, as well as discuss the theoretical basis for the treatment of SCI.

mTOR pathway: A potential therapeutic target for spinal cord injury

Spinal cord injury (SCI) is the most common disabling spinal injury, and the complex pathological process can eventually lead to severe neurological dysfunction. Many studies have reported that the mammalian target of rapamycin (mTOR) signaling pathway plays an important role in synaptogenesis, neuron growth, differentiation, and survival after central nervous system injury. It is also involved in various traumatic and central nervous system diseases, including traumatic brain injury, neonatal hypoxic-ischemic brain injury, Alzheimer's disease, Parkinson's disease, and cerebral apoplexy. mTOR has also been reported to play an important regulatory role in various pathophysiological processes following SCI. Activation of mTOR signals after SCI can regulate physiological and pathological processes, such as proliferation and differentiation of neural stem cells, regeneration of nerve axons, neuroinflammation, and glial scar formation, through various pathways. Inhibition of mTOR activity has been confirmed to promote repair in SCI. At present, many studies have reported that Chinese herbal medicine can inhibit the SCI-activated mTOR pathway to improve the microenvironment and promote nerve repair after SCI. Due to the role of the mTOR pathway in SCI, it may be a potential therapeutic target for SCI. This review is focused on the pathophysiological process of SCI, characteristics of the mTOR pathway, role of the mTOR pathway in SCI, role of inhibition of mTOR on SCI, and role and significance of inhibition of mTOR by related Chinese herbal medicine inhibitors in SCI. In addition, the review discusses the deficiencies and solutions to mTOR and SCI research shortcomings. This study hopes to provide reference for mTOR and SCI research and a theoretical basis for SCI biotherapy.

Anti-inflammatory and antioxidant effects of astaxanthin following spinal cord injury in a rat animal model

Spinal cord injury (SCI) is a severely debilitating problem leading to substantial decrease in the quality of life. After spinal cord injury, inflammation and oxidative stress plays a key role in initiating the secondary injury cascades leading to progressive tissue degradation and extreme functional deficits. Given that the primary mechanical injuries to spinal cord are rarely repaired, the pharmacological interventions may improve the neurological outcomes caused by secondary injury. Astaxanthin (AST) is considered as a xanthophyll carotenoid with potent antioxidant and anti-inflammatory properties, which has various pharmacological activities. In the present study, we aimed to firstly assess the protective effect of AST, and then to define the AST mechanism of action on a rat model of SCI. Based on the results of von Frey test, AST treatment significantly alleviated the SCI-induced neuropathic pain compared with the control groups (P < 0.05). The expression analysis by western blot shows reduced expression levels of COX-2, TNF-α, IL-1β, and IL-6 following AST treatment (P < 0.05). The activity of antioxidant enzymes was evaluated using ELISA. Therefore, ELISA experiments showed a significant reduction in the level of oxidative stress in SCI rat following AST treatment (P < 0.05). Furthermore, histopathological evaluations revealed that myelinated white matter and motor neuron number were significantly preserved after treatment with AST (P < 0.05). In conclusion, our study shows that AST could improve SCI through anti-inflammatory and antioxidant effects which leads to decreased tissue damage and mechanical pain after SCI.

Time-to-enrollment in clinical trials investigating neurological recovery in chronic spinal cord injury: observations from a systematic review and ClinicalTrials.gov database

Currently, large numbers of clinical trials are performed to investigate different forms of experimental therapy for patients suffering from chronic spinal cord injury (SCI). However, for the enrollment process, there are different views on how the time period between injury and interventions should be determined. Herein, we sought to evaluate the impact of time-to-enrollment in chronic SCI clinical trials. A data set comprising 957 clinical studies from clinicalTrials.gov was downloaded and analyzed focusing on the eligibility criteria for post-injury time-to-enrollment. We also aggregated individual patient data from nine clinical trials of regenerative interventions for chronic SCI selected by a systematic literature search from 1990 to 2018. Characteristics of the studies were assessed and compared by dividing into three groups based on time-to-enrollment (group 1 ≤ 12 months, group 2 = 12–23 months and group 3 ≥ 24 months). In ClinicalTrials.gov registry, 445 trials were identified for chronic SCI where 87% (385) were unrestricted in the maximum post-injury time for trial eligibility. From systematic literature search, nine studies and 156 patients (group 1 = 30, group 2 = 55 and group 3 = 71) were included. The range of time-to-enrollment was 0.5 to 321 months in those studies. We also observed various degrees of motor and sensory improvement in between three time-to-enrollment groups. Our results indicate that enrolling wide ranges of time-to-enrollment in a group may present imprecise outcomes. Clinical trial designs should consider appropriate post-injury time frames to evaluate therapeutic benefit.

Dexmedetomidine alleviates traumatic spinal cord injury in rats via inhibiting apoptosis induced by endoplasmic reticulum stress

OBJECTIVE

To investigate the protective effect of dexmedetomidine (Dex) on traumatic spinal cord injury (TSCI) and to evaluate the involvement of inhibition of endoplasmic reticulum (ER) stress response in the potential mechanism.

METHOD

Sprague-Dawley rats were randomly divided into five groups. The hind limb locomotor function of rats was evaluated at 1, 3 and 7 days after the operation. At 7 days after the operation, spinal cord specimens were obtained for hematoxylin and eosin (H&E), Nissl and TUNEL staining, as well as immunofluorescence and Western blot analyses to detect the level of apoptosis and the levels of proteins related to ER stress.

RESULTS

7 days after the operation, Dex treatment promoted the recovery and also inhibited apoptosis of neurons in the spinal cord. Additionally, Dexinhibited the expression of proteins related to ER stress response after spinal cord injury.

CONCLUSIONS

Dex improves the neurological function of rats with TSCI and reduces apoptosis of spinal cord neurons. The potential mechanism is related to the inhibition of the ER stress response.

Repair of Spinal Cord Injury by Inhibition of PLK4 Expression Through Local Delivery of siRNA-Loaded Nanoparticles

Polo-like kinase 4 (PLK4) is one of the key regulators of centrosomal replication. However, its role and mechanism in spinal cord injury (SCI) are still unclear. The SCI model on rats was constructed and the expression and localization of PLK4 in the spinal cord are analyzed with Western blot and immunofluorescence, respectively. Then the specific siRNAs were encapsulated in nanoparticles for the inhibition of PLK4 expression. Afterward, the role of PLK4 on astrocytes was investigated by knocking down its expression in the primary astrocytes. Moreover, siRNA-loaded nanoparticles were injected into the injured spinal cord of rats, and the motor function recovery of rats after SCI was assessed using the Basso, Beattie, and Bresnahan (BBB) locomotor scale method. Notably, the siRNA-loaded nanoparticles effectively transfect primary astrocytes and significantly inhibit PLK4 expression, together with the expression of PCNA with significance. After treatment, restoration of the motor function following SCI was significantly improved in the PLK4 knockdown group compared with the control group. Therefore, we speculate that inhibition of Plk4 may inhibit the proliferation of astrocytes and decrease the inflammatory response mediated by astrocytes, so as to promote the functional recovery of SCI. In conclusion, inhibition of PLK4 expression via siRNA-loaded nanoparticles may be a potential treatment for SCI.

Bioinformatic Analysis of the Proteome in Exosomes Derived From Plasma: Exosomes Involved in Cholesterol Metabolism Process of Patients With Spinal Cord Injury in the Acute Phase

Spinal cord injury (SCI) is a common but severe disease caused by traffic accidents. Coronary atherosclerotic heart disease (CHD) caused by dyslipidemia is known as the leading cause of death in patients with SCI. However, the quantitative analysis showed that the cholesterol and lipoprotein concentrations in peripheral blood (PB) did not change significantly within 48 h after SCI. Due to the presence of the Blood spinal cord barrier (BSCB), there are only few studies concerning the plasma cholesterol metabolism in the acute phase of SCI. Exosomes have a smaller particle size, which enables them relatively less limitation of BSCB. This study uses exosomes derived from the plasma of 43 patients in the acute phase of SCI and 71 patients in the control group as samples. MS proteomics and bioinformatics analysis found 590 quantifiable proteins, in which 75 proteins were upregulated and 153 proteins were downregulated, and the top 10 differentially expressed proteins are those including downregulating proteins: HIST1H4A, HIST2H3A, HIST2H2BE, HCLS1, S100A9, HIST1H2BM, S100A8, CALM3, YWHAH, and SFN, and upregulating proteins: SERPIND1, C1QB, SPTLC3, IGHV4-28, C4A, IGHV4-38-2, IGHV4-30-2, SLC15A1, C4B, and ACTG2. Enrichment analysis showed that the largest part of proteins was related to cholesterol metabolism among the downregulated proteins. The main components of cholesterol [ApoB-48 and ApoB-100 increased, ApoA-I, ApoA-II, ApoA-IV, ApoC, ApoE, and Apo(a) decreased] were changed in exosomes derived from plasma of patients. ELISA analysis showed that some components were disordered in the acute phase of SCI. These results suggested that the exosomes might be involved in cholesterol metabolism regulation in the acute phase of SCI.

Acute spinal cord injury: Pathophysiology and pharmacological intervention (Review)

Spinal cord injury (SCI) is one of the most debilitating of all the traumatic conditions that afflict individuals. For a number of years, extensive studies have been conducted to clarify the molecular mechanisms of SCI. Experimental and clinical studies have indicated that two phases, primary damage and secondary damage, are involved in SCI. The initial mechanical damage is caused by local impairment of the spinal cord. In addition, the fundamental mechanisms are associated with hyperflexion, hyperextension, axial loading and rotation. By contrast, secondary injury mechanisms are led by systemic and cellular factors, which may also be initiated by the primary injury. Although significant advances in supportive care have improved clinical outcomes in recent years, a number of studies continue to explore specific pharmacological therapies to minimize SCI. The present review summarized some important pathophysiologic mechanisms that are involved in SCI and focused on several pharmacological and non‑pharmacological therapies, which have either been previously investigated or have a potential in the management of this debilitating injury in the near future.

Pharmacological management of secondary spinal cord injury

Introduction: Secondary spinal cord injury (SCI) sets on immediately after trauma and, despite prompt treatment, may become chronic. SCI is a complex condition and presents numerous challenges to patients and physicians alike, also considering the lack of an approved pharmacological therapy.Areas covered: This review describes the pathophysiological mechanisms leading to secondary SCI to highlight possible targets for pharmacological therapy. Furthermore, an extensive search of the literature on different databases (PubMed, Google scholar, Embase, and Scopus) and of the current clinical trials (clinicaltrials.gov) was performed to investigate the current outlook for the pharmacological management of SCI. Only drugs with performed or ongoing clinical trials were considered.Expert opinion: Pharmacological therapy aims to improve motor and sensory function in patients. Overall, drugs are divided into neuroprotective compounds, which aim to limit the damage induced by the pro-inflammatory and pro-apoptotic milieu of SCI, and neuroregenerative drugs, which induce neuronal and axonal regrowth. While many compounds have been trialed with promising results, none has yet completed a stage III trial and has been approved for the pharmacological management of SCI.

Effects of combination treatment with transcranial magnetic stimulation and bone marrow mesenchymal stem cell transplantation or Raf inhibition on spinal cord injury in rats

Spinal cord injury (SCI) remains a global challenge due to limited treatment strategies. Transcranial magnetic stimulation (TMS), bone marrow mesenchymal stem cell (BMSC) transplantation and downregulation of Raf/MEK/ERK signaling effectively improve SCI. The combination of BMSCs and TMS displays synergistic effects on vascular dementia. However, whether TMS displays a synergistic effect when combined with BMSC transplantation or Raf inhibitor (RafI) therapy for the treatment of SCI is not completely understood. The present study aimed to compare the therapeutic effect of monotherapy and combination therapy on SCI. In the present study, 8‑week‑old female Sprague Dawley rats were used to establish a model of SCI using the weight‑drop method followed by treatment with monotherapy (TMS, BMSCs or RafI) or combination therapy (TMS+BMSCs or TMS+RafI). The effect of monotherapy and combination therapy on locomotor function, pathological alterations, neuronal apoptosis and expression of axonal regeneration‑associated factors and Raf/MEK/ERK signaling‑associated proteins in the spinal cord was analyzed by Basso, Beattie and Bresnahan (BBB) scoring, hematoxylin and eosin staining, TUNEL‑neuronal nuclei (NeuN) staining and immunofluorescence or western blotting, respectively. The results demonstrated that compared with untreated SCI model rats, monotherapy significantly enhanced locomotor functional recovery, as evidenced by higher BBB scores, and slightly alleviated histopathological lesions of the spinal cord in SCI model rats. Furthermore, monotherapy markedly suppressed neuronal apoptosis and promoted axonal regeneration, as well as inhibiting astroglial activation in SCI model rats. The aforementioned results were demonstrated by significantly decreased numbers of apoptotic neurons, markedly decreased expression levels of glial fibrillary acidic protein (GFAP), significantly increased numbers of NeuN+ cells, markedly increased expression levels of growth‑associated protein 43 (GAP‑43) and significantly upregulated nerve growth factor (NGF) and brain derived neurotrophic factor (BDNF) expression levels in monotherapy groups (excluding the RafI monotherapy group) compared with untreated SCI model rats. In addition, monotherapy markedly suppressed activation of the Raf/MEK/ERK signaling pathway, as evidenced by significantly reduced p‑Raf/Raf, p‑MEK/MEK and p‑ERK/ERK protein expression levels in monotherapy groups (excluding the BMSC monotherapy group) compared with untreated SCI model rats. Notably, combination therapy further alleviated SCI‑induced spinal cord lesions and neuronal apoptosis, increased GAP‑43, NGF and BDNF expression levels, downregulated GFAP expression levels and inhibited activation of the Raf/MEK/ERK signaling pathway in SCI model rats compared with the corresponding monotherapy groups. Therefore, it was hypothesized that compared with monotherapy, combination therapy displayed an improved therapeutic effect on SCI by further suppressing Raf/MEK/ERK signaling. The results of the present study provided an important basis for the clinical application of combination therapy.

The effect of the therapy of "combination 3 methods progression" in patients with neurogenic bowel dysfunction (constipated type): Study protocol for a randomized controlled trial

BACKGROUND

As one of the important manifestations of neurogenic bowel dysfunction, constipation is characterized by high incidence and harmful effects. It has a negative impact on both physical and psychological health of patients. And there are no effective treatment options for this type of disease clinically. Therefore, this study is designed to examine the effect of the therapy of "combination 3 methods progression" in patients with neurogenic bowel dysfunction (constipated type).

METHODS

This is a randomized, controlled, parallel-design clinical trial. A total of 60 patients with neurogenic bowel dysfunction (constipated type) will be randomly assigned to intervention group and control group. The control group will receive 4 weeks of usual rehabilitation care, the intervention group will receive 4 weeks of the therapy of "combination 3 methods progression" in addition to usual rehabilitation care. The primary outcome is the number of spontaneous bowel movement per week. Secondary outcomes are stool characteristics, degree of difficulty in defecation, level of anxiety, level of depression, and level of self-efficacy.

DISCUSSION

The interventions of this protocol have been programmed to alleviate constipation in patients with neurogenic bowel dysfunction. Findings may provide preliminary evidence for clinical efficacy of the therapy of "combination 3 methods progression."

TRIAL REGISTRATION

Chinese Clinical Trial Registry, IDF: ChiCTR2000041463. Registered on December 26, 2020.

Engineered liposomes targeting the gut-CNS Axis for comprehensive therapy of spinal cord injury

Effective curative therapies for spinal cord injury (SCI), which is often accompanied by intestinal complications, are lacking. Potential therapeutic targets include astrocytes and their enteric nervous system counterpart, enteric glial cells (EGCs). Based on shared biomarkers and similar functions of both cell types, we designed an orally administered targeted delivery system in which the neuropeptide apamin, stabilized by sulfur replacement with selenium, was adopted as a targeting moiety, and the liposome surface was protected with a non-covalent cross-linked chitosan oligosaccharide lactate layer. The system effectively permeated through oral absorption barriers, targeted local EGCs and astrocytes after systemic circulation, allowing for comprehensive SCI therapy. Given the involvement of the gut-organ axis in a growing number of diseases, our research may shed light on new aspects of the oral administration route as a bypass for multiple interventions and targeted therapy.

Association of intravenous administration of human Muse cells with deficit amelioration in a rat model of spinal cord injury

OBJECTIVE

Multilineage-differentiating stress-enduring (Muse) cells are pluripotent stem cells, which can be harvested from the bone marrow. After transplantation, Muse cells can migrate to an injured site of the body and exert repair effects. However, it remains unknown whether Muse cell transplantation can be an effective treatment in spinal cord injury (SCI).

METHODS

The authors used a rat model of thoracic spinal cord contusion injury. For Muse cell transplantation, the clinical product CL2020 containing 300,000 Muse cells was administered intravenously 1 day after midthoracic SCI. Animals were divided into CL2020 (n = 11) and vehicle-treated (n = 15) groups. Behavioral and histological evaluations were conducted over a period of 8 weeks to see whether intravenous CL2020 administration provided therapeutic effects for SCI. The effects of human-selective diphtheria toxin on reversion of the therapeutic effects of CL2020 were also investigated.

RESULTS

Hindlimb motor function significantly improved after CL2020 transplantations. Importantly, the effects were reverted by the human-selective diphtheria toxin. In immunohistochemical analyses, the cystic cavity formed after the injury was smaller in the CL2020 group. Furthermore, higher numbers of descending 5-hydroxytryptamine (5-HT) fibers were preserved distal to the injury site after CL2020 administration. Eight weeks after the injury, Muse cells in CL2020 were confirmed to differentiate most predominantly into neuronal cells in the injured spinal cord.

CONCLUSIONS

Following SCI, Muse cells in CL2020 can reach the injured spinal cord after intravenous administration and differentiate into neuronal cells. Muse cells in CL2020 facilitated nerve fiber preservation and exerted therapeutic potential for severe SCI.

Uric acid released from poly(ε-caprolactone) fibers as a treatment platform for spinal cord injury

Spinal cord injury (SCI) is characterized by a primary mechanical phase of injury, resulting in physical tissue damage, and a secondary pathological phase, characterized by biochemical processes contributing to inflammation, neuronal death, and axonal demyelination. Glutamate-induced excitotoxicity (GIE), in which excess glutamate is released into synapses and overstimulates glutamate receptors, is a major event in secondary SCI. GIE leads to mitochondrial damage and dysfunction, release of reactive oxygen species (ROS), DNA damage, and cell death. There is no clinical treatment that targets GIE after SCI, and there is a need for therapeutic targets for secondary damage in patients. Uric acid (UA) acts as an antioxidant and scavenges free radicals, upregulates glutamate transporters on astrocytes, and preserves neuronal viability in in vitro and in vivo SCI models, making it a promising therapeutic candidate. However, development of a drug release platform that delivers UA locally to the injured region in a controlled manner is crucial, as high systemic UA concentrations can be detrimental. Here, we used the electrospinning technique to synthesize UA-containing poly(ɛ-caprolactone) fiber mats that are biodegradable, biocompatible, and have a tunable degradation rate. We optimized delivery of UA as a burst within 20 min from uncoated fibers and sustained release over 2 h with poly(ethylene glycol) diacrylate coating. We found that both of these fibers protected neurons and decreased ROS generation from GIE in organotypic spinal cord slice culture. Thus, fiber mats represent a promising therapeutic for UA release to treat patients who have suffered a SCI.

Mesenchymal Stem Cell-Derived Exosomes: Hope for Spinal Cord Injury Repair

Spinal cord injury (SCI) is a devastating medical condition with profound social and economic impacts. Although research is ongoing, current treatment options are limited and do little to restore functionality. However, recent studies suggest that mesenchymal stem cell-derived exosomes (MSC-exosomes) may hold the key to exciting new treatment options for SCI patients. MSCs are self-renewing multipotent stem cells with multi-directional differentiation and can secrete a large number of exosomes (vesicles secreted into the extracellular environment through endocytosis, called MSC-exosomes). These MSC-exosomes play a critical role in repairing SCI through promoting angiogenesis and axonal growth, regulating inflammation and the immune response, inhibiting apoptosis, and maintaining the integrity of the blood-spinal cord barrier. Furthermore, they can be utilized to transport genetic material or drugs to target cells, and their relatively small size makes them able to permeate the blood-brain barrier. In this review, we summarize recent advances in MSC-exosome themed SCI treatments and cell-free therapies to better understand this newly emerging methodology.

Collateral Circulation in Spinal Cord Injury: A Comprehensive Review

Surgery is the most common cause of spinal cord ischemia; it is also caused by hemodynamic changes, which disrupt the blood flow. Direct ligation of the spinal arteries, especially the Adamkiewicz artery is involved as well. Other causes of spinal cord ischemia include arteriography procedures, thoracic surgery, epidural and rachianesthesia, foraminal infiltration, arterial dissection, systemic hypotension, emboligenic heart disease, thoracic disc herniation, and compression. Understanding the vascular anatomy of the spinal cord is essential to develop optimal strategies for preventing ischemic injuries to the spinal cord. During ischemia, a rich network of intra and paraspinal collaterals allow enough blood flow to compensate the intensity of spinal cord ischemia. In case of interruption of flow of a main artery, the collateral artery increases its flow to maintain perfusion to the tissues. Avoiding spinal cord ischemia by using collateral circulation is necessary to prevent the establishment of hypovolemia, hyperthermia and elevations in venous pressures. The objective of this narrative review is to present the current concepts of spinal collateral circulation and its role in the setting of ischemic events, affecting the vascular supply of the spinal cord.

Revealing the Therapeutic Potential of Botulinum Neurotoxin Type A in Counteracting Paralysis and Neuropathic Pain in Spinally Injured Mice

Botulinum neurotoxin type A (BoNT/A) is a major therapeutic agent that has been proven to be a successful treatment for different neurological disorders, with emerging novel therapeutic indications each year. BoNT/A exerts its action by blocking SNARE complex formation and vesicle release through the specific cleavage of SNAP-25 protein; the toxin is able to block the release of pro-inflammatory molecules for months after its administration. Here we demonstrate the extraordinary capacity of BoNT/A to neutralize the complete paralysis and pain insensitivity induced in a murine model of severe spinal cord injury (SCI). We show that the toxin, spinally administered within one hour from spinal trauma, exerts a long-lasting proteolytic action, up to 60 days after its administration, and induces a complete recovery of muscle and motor function. BoNT/A modulates SCI-induced neuroglia hyperreactivity, facilitating axonal restoration, and preventing secondary cells death and damage. Moreover, we demonstrate that BoNT/A affects SCI-induced neuropathic pain after moderate spinal contusion, confirming its anti-nociceptive action in this kind of pain, as well. Our results provide the intriguing and real possibility to identify in BoNT/A a therapeutic tool in counteracting SCI-induced detrimental effects. Because of the well-documented BoNT/A pharmacology, safety, and toxicity, these findings strongly encourage clinical translation.

Advances in the Signaling Pathways Downstream of Glial-Scar Axon Growth Inhibitors

Axon growth inhibitors generated by reactive glial scars play an important role in failure of axon regeneration after CNS injury in mature mammals. Among the inhibitory factors, chondroitin sulfate proteoglycans (CSPGs) are potent suppressors of axon regeneration and are important molecular targets for designing effective therapies for traumatic brain injury or spinal cord injury (SCI). CSPGs bind with high affinity to several transmembrane receptors, including two members of the leukocyte common antigen related (LAR) subfamily of receptor protein tyrosine phosphatases (RPTPs). Recent studies demonstrate that multiple intracellular signaling pathways downstream of these two RPTPs mediate the growth-inhibitory actions of CSPGs. A better understanding of these signaling pathways may facilitate development of new and effective therapies for CNS disorders characterized by axonal disconnections. This review will focus on recent advances in the downstream signaling pathways of scar-mediated inhibition and their potential as the molecular targets for CNS repair.