Inflammation: A Target for Treatment in Spinal Cord Injury

Functional biomaterials for modulating the dysfunctional pathological microenvironment of spinal cord injury

Spinal cord injury (SCI) often results in irreversible loss of sensory and motor functions, and most SCIs are incurable with current medical practice. One of the hardest challenges in treating SCI is the development of a dysfunctional pathological microenvironment, which mainly comprises excessive inflammation, deposition of inhibitory molecules, neurotrophic factor deprivation, glial scar formation, and imbalance of vascular function. To overcome this challenge, implantation of functional biomaterials at the injury site has been regarded as a potential treatment for modulating the dysfunctional microenvironment to support axon regeneration, remyelination at injury site, and functional recovery after SCI. This review summarizes characteristics of dysfunctional pathological microenvironment and recent advances in biomaterials as well as the technologies used to modulate inflammatory microenvironment, regulate inhibitory microenvironment, and reshape revascularization microenvironment. Moreover, technological limitations, challenges, and future prospects of functional biomaterials to promote efficient repair of SCI are also discussed. This review will aid further understanding and development of functional biomaterials to regulate pathological SCI microenvironment.

Effects of spinal cord injury associated exosomes delivered tRF-41 on the progression of spinal cord injury progression

BACKGROUND

Spinal cord injury (SCI) is a devastating neurological and pathological condition. Exosomal tsRNAs have reported to be promising biomarkers for cancer diagnosis and therapy. This study aimed to investigate the roles of SCI-associated exosomes, and related tsRNA mechanisms in SCI.

METHODS

The serum of healthy controls and SCI patients at the acute stage were collected for exosomes isolation, and the two different exosomes were used to treat human astrocytes (HA). The cell viability, apoptosis, and cycle were determined, and the expression of the related proteins were detected by western blot. Then, the two different exosomes were sent for tsRNA sequencing, and four significant known differentially expressed tsRNAs (DE-tsRNAs) were selected for RT-qPCR validation. Finally, tRT-41 was chosen to further explore its roles and related mechanisms in SCI.

RESULTS

After sequencing, 21 DE-tsRNAs were identified, which were significantly enriched in pathways of Apelin, AMPK, Hippo, MAPK, Ras, calcium, PI3K-Akt, and Rap1. RT-qPCR showed that tRF-41 had higher levels in the SCI-associated exosomes. Compared with the control HA, healthy exosomes did not significantly affect the growth of HA cells, but SCI-associated exosomes inhibited viability of HA cells, while promoted their apoptosis and increased the HA cells in G2/M phase; but tRF-41 inhibitor reversed the actions of SCI-associated exosomes. Additionally, SCI-associated exosomes, similar with tRF-41 mimics, down-regulated IGF-1, NGF, Wnt3a, and β-catenin, while up-regulated IL-1β and IL-6; but tRF-41 inhibitor had the opposite actions, and reversed the effects induced by SCI-associated exosomes.

CONCLUSIONS

SCI-associated exosomes delivered tRF-41 may inhibit the growth of HA through regulating Wnt/ β-catenin pathway and inflammation response, thereby facilitating the progression of SCI.

Analysis of gene expression in microglial apoptotic cell clearance following spinal cord injury based on machine learning algorithms

Spinal cord injury (SCI) is a severe neurological complication following spinal fracture, which has long posed a challenge for clinicians. Microglia play a dual role in the pathophysiological process after SCI, both beneficial and detrimental. The underlying mechanisms of microglial actions following SCI require further exploration. The present study combined three different machine learning algorithms, namely weighted gene co-expression network analysis, random forest analysis and least absolute shrinkage and selection operator analysis, to screen for differentially expressed genes in the GSE96055 microglia dataset after SCI. It then used protein-protein interaction networks and gene set enrichment analysis with single genes to investigate the key genes and signaling pathways involved in microglial function following SCI. The results indicated that microglia not only participate in neuroinflammation but also serve a significant role in the clearance mechanism of apoptotic cells following SCI. Notably, bioinformatics analysis and lipopolysaccharide + UNC569 (a MerTK-specific inhibitor) stimulation of BV2 cell experiments showed that the expression levels of Anxa2, Myo1e and Spp1 in microglia were significantly upregulated following SCI, thus potentially involved in regulating the clearance mechanism of apoptotic cells. The present study suggested that Anxa2, Myo1e and Spp1 may serve as potential targets for the future treatment of SCI and provided a theoretical basis for the development of new methods and drugs for treating SCI.

Inflammatory response in traumatic brain and spinal cord injury: The role of XCL1-XCR1 axis and T cells

BACKGROUND

Traumatic brain injury (TBI) and spinal cord injury (SCI) are acquired injuries to the central nervous system (CNS) caused by external forces that cause temporary or permanent sensory and motor impairments and the potential for long-term disability or even death. These conditions currently lack effective treatments and impose substantial physical, social, and economic burdens on millions of people and families worldwide. TBI and SCI involve intricate pathological mechanisms, and the inflammatory response contributes significantly to secondary injury in TBI and SCI. It plays a crucial role in prolonging the post-CNS trauma period and becomes a focal point for a potential therapeutic intervention. Previous research on the inflammatory response has traditionally concentrated on glial cells, such as astrocytes and microglia. However, increasing evidence highlights the crucial involvement of lymphocytes in the inflammatory response to CNS injury, particularly CD8+ T cells and NK cells, along with their downstream XCL1-XCR1 axis.

OBJECTIVE

This review aims to provide an overview of the role of the XCL1-XCR1 axis and the T-cell response in inflammation caused by TBI and SCI and identify potential targets for therapy.

METHODS

We conducted a comprehensive search of PubMed and Web of Science using relevant keywords related to the XCL1-XCR1 axis, T-cell response, TBI, and SCI.

RESULTS

This study examines the upstream and downstream pathways involved in inflammation caused by TBI and SCI, including interleukin-15 (IL-15), interleukin-12 (IL-12), CD8+ T cells, CD4+ T cells, NK cells, XCL1, XCR1+ dendritic cells, interferon-gamma (IFN-γ), helper T0 cells (Th0 cells), helper T1 cells (Th1 cells), and helper T17 cells (Th17 cells). We describe their proinflammatory effect in TBI and SCI.

CONCLUSIONS

The findings suggest that the XCL1-XCR1 axis and the T-cell response have great potential for preclinical investigations and treatments for TBI and SCI.

Exploring the Landscape of Hydrogel Therapy for Spinal Cord Injury: A Bibliometric and Visual Analysis (1991-2023)

BACKGROUND

This study aimed to conduct a bibliometric analysis of the literature on hydrogel therapy for spinal cord injury to visualize the research status, identify hotspots, and explore the development trends in this field.

METHODS

Web of science Core Collection database was searched for relevant studies published between January 1991 and December 2023. Data such as journal title, author information, institutional affiliation, country, citation, and keywords were extracted. Bibliometrix, CiteSpace, and VOSviewer were used to perform bibliometric analysis of the retrieved data.

RESULTS

A total of 1099 articles pertaining to hydrogel therapy for spinal cord injury were retrieved, revealing an upward trajectory in both annual publication volume and cumulative publication volume. Biomaterials emerged as the journal with the highest number of publications and the most rapid cumulative publication growth, contributing 84 articles. Among authors, Shoichet MS stood out with the highest number of publications and citations, totaling 66 articles. The University of Toronto led in institutional contributions with 65 publications, while China dominated in country-specific publications, accounting for 374 articles. However, to foster significant academic achievements, it is imperative for diverse authors, institutions, and countries to enhance collaboration. Current research in this field concentrates on scaffold architecture, nerve growth factor, the fibrotic microenvironment, and guidance channels. Simultaneously, upcoming research directions prioritize 3D bioprinting, injectable hydrogel, inflammation, and nanoparticles within the realm of hydrogel therapy for spinal cord injuries.

CONCLUSIONS

In summary, this study provided a comprehensive analysis of the current research status and frontiers of hydrogel therapy for spinal cord injury. The findings provide a foundation for future research and clinical translation efforts of hydrogel therapy in this field.

Applications of Stem Cell-Derived Extracellular Vesicles in Nerve Regeneration

Extracellular vesicles (EVs), including exosomes, microvesicles, and other lipid vesicles derived from cells, play a pivotal role in intercellular communication by transferring information between cells. EVs secreted by progenitor and stem cells have been associated with the therapeutic effects observed in cell-based therapies, and they also contribute to tissue regeneration following injury, such as in orthopaedic surgery cases. This review explores the involvement of EVs in nerve regeneration, their potential as drug carriers, and their significance in stem cell research and cell-free therapies. It underscores the importance of bioengineers comprehending and manipulating EV activity to optimize the efficacy of tissue engineering and regenerative therapies.

Imaging demyelinated axons after spinal cord injuries with PET tracer [ 18 F]3F4AP

Spinal cord injuries (SCI) often lead to lifelong disability. Among the various types of injuries, incomplete and discomplete injuries, where some axons remain intact, offer potential for recovery. However, demyelination of these spared axons can worsen disability. Demyelination is a reversible phenomenon, and drugs like 4-aminopyridine (4AP), which target K+ channels in demyelinated axons, show that conduction can be restored. Yet, accurately assessing and monitoring demyelination post-SCI remains challenging due to the lack of suitable imaging methods. In this study, we introduce a novel approach utilizing the positron emission tomography (PET) tracer, [ 18 F]3F4AP, specifically targeting K+ channels in demyelinated axons for SCI imaging. Rats with incomplete contusion injuries were imaged up to one month post-injury, revealing [ 18 F]3F4AP's exceptional sensitivity to injury and its ability to detect temporal changes. Further validation through autoradiography and immunohistochemistry confirmed [ 18 F]3F4AP's targeting of demyelinated axons. In a proof-of-concept study involving human subjects, [ 18 F]3F4AP differentiated between a severe and a largely recovered incomplete injury, indicating axonal loss and demyelination, respectively. Moreover, alterations in tracer delivery were evident on dynamic PET images, suggestive of differences in spinal cord blood flow between the injuries. In conclusion, [ 18 F]3F4AP demonstrates efficacy in detecting incomplete SCI in both animal models and humans. The potential for monitoring post-SCI demyelination changes and response to therapy underscores the utility of [ 18 F]3F4AP in advancing our understanding and management of spinal cord injuries.

Amelioration of functional and histopathological consequences after spinal cord injury through phosphodiesterase 4D (PDE4D) inhibition

Spinal cord injury (SCI) is a life-changing event that severely impacts the patient's quality of life. Modulating neuroinflammation, which exacerbates the primary injury, and stimulating neuro-regenerative repair mechanisms are key strategies to improve functional recovery. Cyclic adenosine monophosphate (cAMP) is a second messenger crucially involved in both processes. Following SCI, intracellular levels of cAMP are known to decrease over time. Therefore, preventing cAMP degradation represents a promising strategy to suppress inflammation while stimulating regeneration. Intracellular cAMP levels are controlled by its hydrolyzing enzymes phosphodiesterases (PDEs). The PDE4 family is most abundantly expressed in the central nervous system (CNS) and its inhibition has been shown to be therapeutically relevant for managing SCI pathology. Unfortunately, the use of full PDE4 inhibitors at therapeutic doses is associated with severe emetic side effects, hampering their translation toward clinical applications. Therefore, in this study, we evaluated the effect of inhibiting specific PDE4 subtypes (PDE4B and PDE4D) on inflammatory and regenerative processes following SCI, as inhibitors selective for these subtypes have been demonstrated to be well-tolerated. We reveal that administration of the PDE4D inhibitor Gebr32a, even when starting 2 dpi, but not the PDE4B inhibitor A33, improved functional as well as histopathological outcomes after SCI, comparable to results obtained with the full PDE4 inhibitor roflumilast. Furthermore, using a luminescent human iPSC-derived neurospheroid model, we show that PDE4D inhibition stabilizes neural viability by preventing apoptosis and stimulating neuronal differentiation. These findings strongly suggest that specific PDE4D inhibition offers a novel therapeutic approach for SCI.

Conditional deletion of IκBζ in hematopoietic cells promotes functional recovery after spinal cord injury in mice

BACKGROUND

Transcription factor protein IκBζ (encoded by the Nfkbiz gene) regulates nuclear factor-κB (NF-κB) and is involved in the pathophysiology of various inflammatory diseases. However, the role of IκBζ in secondary damage following spinal cord injury (SCI) remains to be determined. Here, we investigated the effect of IκBζ expressed in hematopoietic cells on the progression of secondary damage and functional recovery after SCI.

METHODS

We used conditional IκBζ-knockout mice (Mx1-Cre;Nfkbizfl/f) to examine the role of IκBζ in hematopoietic cells after SCI. Contusion SCI was induced using a force of 60 kdyn. The recovery of locomotor performance was evaluated using the nine-point Basso Mouse Scale (BMS) until 42 days post-injury. Expression patterns of inflammatory cytokines and chemokines were examined by quantitative real-time PCR or proteome array analysis. Bone marrow transplantation (BMT) was performed to eliminate the effect of IκBζ deletion in non-hematopoietic cells.

RESULTS

Mx1-Cre;Nfkbizfl/fl mice had significantly improved locomotor function compared with wild-type (WT) mice. The mRNA expression of Nfkbiz in WT mice peaked at 12 h after SCI and then decreased slowly in both the spinal cord and white blood cells. In situ hybridization showed that Nfkbiz mRNA was localized in cell nuclei, including macrophage-like cells, in the injured spinal cord of WT mice at 1 day after SCI. Compared with WT mice, Mx1-Cre;Nfkbizfl/fl mice had significantly increased mRNA expressions of interleukin (Il)-4 and Il-10 in the injured spinal cord. In addition, Mx1-Cre;Nfkbizfl/fl mice had significantly higher protein levels of granulocyte-macrophage colony-stimulating factor and C-C motif chemokine 11 compared with WT mice. BMT from Mx1-Cre;Nfkbizfl/fl mice into WT mice improved functional recovery after SCI compared with control mice (WT cells into WT mice).

CONCLUSIONS

IκBζ deletion in hematopoietic cells improved functional recovery after SCI, possibly by shifting the inflammatory balance towards anti-inflammatory and pro-regenerative directions.

Uncovering the shared neuro-immune-related regulatory mechanisms between spinal cord injury and osteoarthritis

Adults with spinal cord injury (SCI), a destructive neurological injury, have a significantly higher incidence of osteoarthritis (OA), a highly prevalent chronic joint disorder. This study aimed to dissect the neuroimmune-related regulatory mechanisms of SCI and OA using bioinformatics analysis. Using microarray data from the Gene Expression Omnibus database, differentially expressed genes (DEGs) were screened between SCI and sham samples and between OA and control samples. Common DEGs were used to construct a protein-protein interaction (PPI) network. Weighted gene co-expression network analysis (WGCNA) was used to mine SCI- and OA-related modules. Shared miRNAs were identified, and target genes were predicted using the Human MicroRNA Disease Database (HMDD) database. A miRNA-gene-pathway regulatory network was constructed with overlapping genes, miRNAs, and significantly enriched pathways. Finally, the expression of the identified genes and miRNAs was verified using RT-qPCR. In both the SCI and OA groups, 185 common DEGs were identified, and three hub clusters were obtained from the PPI network. WGCNA revealed three SCI-related modules and two OA-related modules. There were 43 overlapping genes between the PPI network clusters and the WGCNA network modules. Seventeen miRNAs shared between patients with SCI and OA were identified. A regulatory network consisting of five genes, six miRNAs, and six signaling pathways was constructed. Upregulation of CD44, TGFBR1, CCR5, and IGF1, while lower levels of miR-125b-5p, miR-130a-3p, miR-16-5p, miR-204-5p, and miR-204-3p in both SCI and OA were successfully verified using RT-qPCR. Our study suggests that a miRNA-gene-pathway network is implicated in the neuroimmune-related regulatory mechanisms of SCI and OA. CD44, TGFBR1, CCR5, and IGF1, and their related miRNAs (miR-125b-5p, miR-130a-3p, miR-16-5p, miR-204-5p, and miR-204-3p) may serve as promising biomarkers and candidate therapeutic targets for SCI and OA.

Crosstalk Between Cell Death and Spinal Cord Injury: Neurology and Therapy

Spinal cord injury (SCI) often leads to neurological dysfunction, and neuronal cell death is one of the main causes of neurological dysfunction. After SCI, in addition to necrosis, programmed cell death (PCD) occurs in nerve cells. At first, studies recognized only necrosis, apoptosis, and autophagy. In recent years, researchers have identified new forms of PCD, including pyroptosis, necroptosis, ferroptosis, and cuproptosis. Related studies have confirmed that all of these cell death modes are involved in various phases of SCI and affect the direction of the disease through different mechanisms and pathways. Furthermore, regulating neuronal cell death after SCI through various means has been proven to be beneficial for the recovery of neural function. In recent years, emerging therapies for SCI have also provided new potential methods to restore neural function. Thus, the relationship between SCI and cell death plays an important role in the occurrence and development of SCI. This review summarizes and generalizes the relevant research results on neuronal necrosis, apoptosis, autophagy, pyroptosis, necroptosis, ferroptosis, and cuproptosis after SCI to provide a new understanding of neuronal cell death after SCI and to aid in the treatment of SCI.

Long non-coding RNA DANCR increases spinal cord neuron apoptosis and inflammation of spinal cord injury by mediating the microRNA-146a-5p/MAPK6 axis

OBJECTIVE

This research was to unravel the impact of the lncRNA differentiation antagonizing non-protein coding RNA (DANCR)/microRNA (miR)-146a-5p/mitogen-activated protein kinase 6 (MAPK6) axis on spinal cord injury (SCI).

METHODS

SCI mouse models were established and injected with si-DANCR or miR-146a-5p agomir. The recovery of motor function was assessed by Basso Mouse Scale. SCI was pathologically evaluated, and serum inflammatory factors were measured in SCI mice. Mouse spinal cord neurons were injured by H2O2 and transfected, followed by assessment of proliferation and apoptosis. DANCR, miR-146a-5p, and MAPK6 in tissues and cells were detected, as well as their relationship.

RESULTS

DANCR increased and miR-146a-5p decreased in SCI. Silencing DANCR or enhancing miR-146a-5p stimulated the proliferation of mouse spinal cord neurons and reduced apoptosis. DANCR was bound to miR-146a-5p to target MAPK6. DANCR affected the proliferation and apoptosis of spinal cord neurons by mediating the miR-146a-5p/MAPK6 axis. Downregulating DANCR or upregulating miR-146a-5p improved inflammation, the destruction of spinal cord tissue structure, and apoptosis in SCI mice.

CONCLUSION

DANCR affects spinal cord neuron apoptosis and inflammation of SCI by mediating the miR-146a-5p/MAPK6 axis.

TP53INP2 knockdown inhibits inflammatory response and apoptosis after spinal cord injury

BACKGROUND

Spinal cord injury (SCI) is a traumatic neurological disorder with limited therapeutic options. Tumor protein p53-inducible nuclear protein 2 (TP53INP2) is involved in the occurrence and development of various diseases, and it may play a role during SCI via affecting inflammation and neuronal apoptosis. This study investigated the associated roles and mechanisms of TP53INP2 in SCI.

METHODS

Mouse and lipopolysaccharide (LPS)-induced SCI BV-2 cell models were constructed to explore the role of TP53INP2 in SCI and the associated mechanisms. Histopathological evaluation of spinal cord tissue was detected by hematoxylin and eosin staining. The Basso, Beattie, and Bresnahan score was used to measure the motor function of the mice, while the spinal cord water content was used to assess spinal cord edema. The expression of TP53INP2 was measured using RT-qPCR. In addition, inflammatory factors in the spinal cord tissue of SCI mice and LPS-treated BV-2 cells were measured using enzyme-linked immunosorbent assay. Apoptosis and related protein expression levels were detected by flow cytometry and western blot analysis, respectively.

RESULTS

TP53INP2 levels increased in SCI mice and LPS-treated BV-2 cells. The results of in vivo and in vitro experiments showed that TP53INP2 knockdown inhibited the inflammatory response and neuronal apoptosis in mouse spinal cord tissue or LPS-induced BV-2 cells.

CONCLUSIONS

After spinal cord injury, TP53INP2 was upregulated, and TP53INP2 knockdown inhibited the inflammatory response and apoptosis.

Non-stem cell-derived exosomes: a novel therapeutics for neurotrauma

Neurotrauma, encompassing traumatic brain injuries (TBI) and spinal cord injuries (SCI) impacts a significant portion of the global population. While spontaneous recovery post-TBI or SCI is possible, recent advancements in cell-based therapies aim to bolster these natural reparative mechanisms. Emerging research indicates that the beneficial outcomes of such therapies might be largely mediated by exosomes secreted from the administered cells. While stem cells have garnered much attention, exosomes derived from non-stem cells, including neurons, Schwann cells, microglia, and vascular endothelial cells, have shown notable therapeutic potential. These exosomes contribute to angiogenesis, neurogenesis, and axon remodeling, and display anti-inflammatory properties, marking them as promising agents for neurorestorative treatments. This review provides an in-depth exploration of the current methodologies, challenges, and future directions regarding the therapeutic role of non-stem cell-derived exosomes in neurotrauma.

The acute spinal cord injury microenvironment and its impact on the homing of mesenchymal stem cells

Spinal cord injury (SCI) is a highly debilitating condition that inflicts devastating harm on the lives of affected individuals, underscoring the urgent need for effective treatments. By activating inflammatory cells and releasing inflammatory factors, the secondary injury response creates an inflammatory microenvironment that ultimately determines whether neurons will undergo necrosis or regeneration. In recent years, mesenchymal stem cells (MSCs) have garnered increasing attention for their therapeutic potential in SCI. MSCs not only possess multipotent differentiation capabilities but also have homing abilities, making them valuable as carriers and mediators of therapeutic agents. The inflammatory microenvironment induced by SCI recruits MSCs to the site of injury through the release of various cytokines, chemokines, adhesion molecules, and enzymes. However, this mechanism has not been previously reported. Thus, a comprehensive exploration of the molecular mechanisms and cellular behaviors underlying the interplay between the inflammatory microenvironment and MSC homing is crucial. Such insights have the potential to provide a better understanding of how to harness the therapeutic potential of MSCs in treating inflammatory diseases and facilitating injury repair. This review aims to delve into the formation of the inflammatory microenvironment and how it influences the homing of MSCs.

Unravelling the Road to Recovery: Mechanisms of Wnt Signalling in Spinal Cord Injury

Spinal cord injury (SCI) is a complex neurodegenerative pathology that consistently harbours a poor prognostic outcome. At present, there are few therapeutic strategies that can halt neuronal cell death and facilitate functional motor recovery. However, recent studies have highlighted the Wnt pathway as a key promoter of axon regeneration following central nervous system (CNS) injuries. Emerging evidence also suggests that the temporal dysregulation of Wnt may drive cell death post-SCI. A major challenge in SCI treatment resides in developing therapeutics that can effectively target inflammation and facilitate glial scar repair. Before Wnt signalling is exploited for SCI therapy, further research is needed to clarify the implications of Wnt on neuroinflammation during chronic stages of injury. In this review, an attempt is made to dissect the impact of canonical and non-canonical Wnt pathways in relation to individual aspects of glial and fibrotic scar formation. Furthermore, it is also highlighted how modulating Wnt activity at chronic time points may aid in limiting lesion expansion and promoting axonal repair.

Neuroprotective effects of tetramethylpyrazine on spinal cord injury-Related neuroinflammation mediated by P2X7R/NLRP3 interaction

OBJECTIVE

The inflammatory response is acknowledged as a crucial pathological aspect of spinal cord injury (SCI). Tetramethylpyrazine (TMP) has been demonstrated to possess neuroprotective properties within the central nervous system via its anti-inflammatory mechanisms. This study aims to investigate the molecular mechanism by which TMP alleviates SCI from an anti-inflammatory standpoint.

METHODS

The SCI model was established using the MASCIS impactor device. The Basso-Beattie-Bresnahan (BBB) locomotor rating scale was utilised to assess rat locomotion. Nissl and Golgi staining were used to observe neuron and dendritic spine morphology, respectively. A transmission electron microscope was used to observe the microcosmic morphology of the axon. ELISA kits were used to measure the concentrations of IL-1β and IL-18 in the spinal cord. Immunofluorescence staining was used to detect P2X7R+/IBA-1+ cells, and Western blot and RT-qPCR were used to analyze the protein and mRNA expression of P2X7R in the spinal cord. Additionally, Western blot was used to detect NLRP3 and Cleaved-Caspase-1 (p20), the critical proteins in the NLRP3 inflammasome pathway.

RESULTS

TMP ameliorated the microcosmic morphology of the axon and had an inhibitory effect on the concentrations of IL-1β and IL-18 after SCI. Furthermore, TMP inhibited the expression of both P2X7R and critical proteins of the NLRP3 inflammasome pathway on microglia after SCI. The aforementioned effects of TMP exhibit similarities to those of BBG (P2X7R antagonist); however, they can be effectively reversed by BzATP (P2X7R activator).

CONCLUSION

TMP alleviated SCI via reducing tissue damage, neuroinflammation, and the expression of P2X7R, NLRP3, IL-1β, and IL-18.

Emerging functions and therapeutic targets of IL-38 in central nervous system diseases

Interleukin (IL)-38 is a newly discovered cytokine of the IL-1 family, which binds various receptors (i.e., IL-36R, IL-1 receptor accessory protein-like 1, and IL-1R1) in the central nervous system (CNS). The hallmark physiological function of IL-38 is competitive binding to IL-36R, as does the IL-36R antagonist. Emerging research has shown that IL-38 is abnormally expressed in the serum and brain tissue of patients with ischemic stroke (IS) and autism spectrum disorder (ASD), suggesting that IL-38 may play an important role in neurological diseases. Important advances include that IL-38 alleviates neuromyelitis optica disorder (NMOD) by inhibiting Th17 expression, improves IS by protecting against atherosclerosis via regulating immune cells and inflammation, and reduces IL-1β and CXCL8 release through inhibiting human microglial activity post-ASD. In contrast, IL-38 mRNA is markedly increased and is mainly expressed in phagocytes in spinal cord injury (SCI). IL-38 ablation attenuated SCI by reducing immune cell infiltration. However, the effect and underlying mechanism of IL-38 in CNS diseases remain inadequately characterized. In this review, we summarize the biological characteristics, pathophysiological role, and potential mechanisms of IL-38 in CNS diseases (e.g., NMOD, Alzheimer's disease, ASD, IS, TBI, and SCI), aiming to explore the therapeutic potential of IL-38 in the prevention and treatment of CNS diseases.

Nicotinamide Riboside Regulates Chemotaxis to Decrease Inflammation and Ameliorate Functional Recovery Following Spinal Cord Injury in Mice

Changes in intracellular nicotinamide adenine dinucleotide (NAD+) levels have been observed in various disease states. A decrease in NAD+ levels has been noted following spinal cord injury (SCI). Nicotinamide riboside (NR) serves as the precursor of NAD+. Previous research has demonstrated the anti-inflammatory and apoptosis-reducing effects of NR supplements. However, it remains unclear whether NR exerts a similar role in mice after SCI. The objective of this study was to investigate the impact of NR on these changes in a mouse model of SCI. Four groups were considered: (1) non-SCI without NR (Sham), (2) non-SCI with NR (Sham +NR), (3) SCI without NR (SCI), and (4) SCI with NR (SCI + NR). Female C57BL/6J mice aged 6-8 weeks were intraperitoneally administered with 500 mg/kg/day NR for a duration of one week. The supplementation of NR resulted in a significant elevation of NAD+ levels in the spinal cord tissue of mice after SCI. In comparison to the SCI group, NR supplementation exhibited regulatory effects on the chemotaxis/recruitment of leukocytes, leading to reduced levels of inflammatory factors such as IL-1β, TNF-α, and IL-22 in the injured area. Moreover, NR supplementation notably enhanced the survival of neurons and synapses within the injured area, ultimately resulting in improved motor functions after SCI. Therefore, our research findings demonstrated that NR supplementation had inhibitory effects on leukocyte chemotaxis, anti-inflammatory effects, and could significantly improve the immune micro-environment after SCI, thereby promoting neuronal survival and ultimately enhancing the recovery of motor functions after SCI. NR supplementation showed promise as a potential clinical treatment strategy for SCI.

Neutrophil-to-lymphocyte ratio at admission for early diagnosis, severity assessment, and prognosis of acute traumatic spinal cord injury

STUDY DESIGN

A retrospective study.

OBJECTIVE

This study examined the value of neutrophil-to-lymphocyte ratio at admission for early diagnosis, severity assessment, and prognosis of acute traumatic SCI.

SETTING

The First People's Hospital of Neijiang, China.

METHODS

This was a single-center, retrospective, cohort study of patients treated within 12 h of acute SCI between January 2018 and October 2022. Ninety-four SCI patients were selected as the Observation group, including 26 with complete injury (AIS grade A) and 68 with incomplete injury (AIS grade B-D), while 94 patients with simple spinal fracture were randomly selected as the Control group. Eighty-one observation group patients underwent surgical treatment, of which 33 had a higher AIS grade (Good prognosis subgroup) and 48 a lower or equal grade post-surgery (Poor prognosis subgroup). Univariate and multivariate analyses were performed to assess predictors of early diagnosis, severity, and 6-month outcome.

RESULTS

Initial white blood cell count, neutrophil count, monocyte count, and NLR were higher in the Observation group than the Control group, while lymphocyte count was lower in the Observation group. Multivariate logistic regression analysis identified NLR as an independent predictor of early diagnosis. Spinal canal encroachment ≥50%, neutrophil count, and NLR were higher in the complete injury subgroup, and spinal canal encroachment ≥50% was an independent predictor of complete injury, while NLR was not. The NLR was higher in the poor prognosis subgroup and was an independent risk factor.

CONCLUSIONS

Peripheral blood NLR is useful for early diagnosis of acute SCI and is predictive of clinical outcome.

Impact of inflammation and Treg cell regulation on neuropathic pain in spinal cord injury: mechanisms and therapeutic prospects

Spinal cord injury is a severe neurological trauma that can frequently lead to neuropathic pain. During the initial stages following spinal cord injury, inflammation plays a critical role; however, excessive inflammation can exacerbate pain. Regulatory T cells (Treg cells) have a crucial function in regulating inflammation and alleviating neuropathic pain. Treg cells release suppressor cytokines and modulate the function of other immune cells to suppress the inflammatory response. Simultaneously, inflammation impedes Treg cell activity, further intensifying neuropathic pain. Therefore, suppressing the inflammatory response while enhancing Treg cell regulatory function may provide novel therapeutic avenues for treating neuropathic pain resulting from spinal cord injury. This review comprehensively describes the mechanisms underlying the inflammatory response and Treg cell regulation subsequent to spinal cord injury, with a specific focus on exploring the potential mechanisms through which Treg cells regulate neuropathic pain following spinal cord injury. The insights gained from this review aim to provide new concepts and a rationale for the therapeutic prospects and direction of cell therapy in spinal cord injury-related conditions.

Spinal Cord Injury: From MicroRNAs to Exosomal MicroRNAs

Spinal cord injury (SCI) is an unfortunate experience that may generate extensive sensory and motor disabilities due to the destruction and passing of nerve cells. MicroRNAs are small RNA molecules that do not code for proteins but instead serve to regulate protein synthesis by targeting messenger RNA's expression. After SCI, secondary damage like apoptosis, oxidative stress, inflammation, and autophagy occurs, and differentially expressed microRNAs show a function in these procedures. Almost all animal and plant cells release exosomes, which are sophisticated formations of lipid membranes. These exosomes have the capacity to deliver significant materials, such as proteins, RNAs and lipids, to cells in need, regulating their functions and serving as a way of communication. This new method offers a fresh approach to treating spinal cord injury. Obviously, the exosome has the benefit of conveying the transported material across performing regulatory activities and the blood-brain barrier. Among the exosome cargoes, microRNAs, which modulate their mRNA targets, show considerable promise in the pathogenic diagnosis, process, and therapy of SCI. Herein, we describe the roles of microRNAs in SCI. Furthermore, we emphasize the importance of exosomal microRNAs in this disease.

The Role of Interleukin-10 in the Pathogenesis and Treatment of a Spinal Cord Injury

Spinal cord injury (SCI) is a devastating condition that often leads to severe and permanent neurological deficits. The complex pathophysiology of an SCI involves a cascade of events, including inflammation, oxidative stress, and secondary injury processes. Among the myriad of molecular players involved, interleukin-10 (IL-10) emerges as a key regulator with the potential to modulate both the inflammatory response and promote neuroprotection. This comprehensive review delves into the intricate interplay of IL-10 in the pathogenesis of an SCI and explores its therapeutic implications in the quest for effective treatments. IL-10 has been found to regulate inflammation, oxidative stress, neuronal apoptosis, and glial scars after an SCI. Its neuroprotective properties have been evaluated in a plethora of animal studies. IL-10 administration, either isolated or in combination with other molecules or biomaterials, has shown neuroprotective effects through a reduction in inflammation, the promotion of tissue repair and regeneration, the modulation of glial scar formation, and improved functional outcomes. In conclusion, IL-10 emerges as a pivotal player in the pathogenesis and treatment of SCIs. Its multifaceted role in modulating inflammation, oxidative stress, neuronal apoptosis, glial scars, and neuroprotection positions IL-10 as a promising therapeutic target. The ongoing research exploring various strategies for harnessing the potential of IL-10 offers hope for the development of effective treatments that could significantly improve outcomes for individuals suffering from spinal cord injuries. As our understanding of IL-10's intricacies deepens, it opens new avenues for innovative and targeted therapeutic interventions, bringing us closer to the goal of alleviating the profound impact of SCIs on patients' lives.

Role of NLRP3 Inflammasome in Post-Spinal-Cord-Injury Anxiety and Depression: Molecular Mechanisms and Therapeutic Implications

The majority of research on the long-term effects of spinal cord injury (SCI) has primarily focused on neuropathic pain (NP), psychological issues, and sensorimotor impairments. Among SCI patients, mood disorders, such as anxiety and depression, have been extensively studied. It has been found that chronic stress and NP have negative consequences and reduce the quality of life for individuals living with SCI. Our review examined both human and experimental evidence to explore the connection between mood changes following SCI and inflammatory pathways, with a specific focus on NLRP3 inflammasome signaling. We observed increased proinflammatory factors in the blood, as well as in the brain and spinal cord tissues of SCI models. The NLRP3 inflammasome plays a crucial role in various diseases by controlling the release of proinflammatory molecules like interleukin 1β (IL-1β) and IL-18. Dysregulation of the NLRP3 inflammasome in key brain regions associated with pain processing, such as the prefrontal cortex and hippocampus, contributes to the development of mood disorders following SCI. In this review, we summarized recent research on the expression and regulation of components related to NLRP3 inflammasome signaling in mood disorders following SCI. Finally, we discussed potential therapeutic approaches that target the NLRP3 inflammasome and regulate proinflammatory cytokines as a way to treat mood disorders following SCI.

Wnt-3a improves functional recovery after spinal cord injury by regulating the inflammatory and apoptotic response in rats via wnt/β-catenin signaling pathway

The specific molecular mechanism of neuroprotective effects of wnt-3a on spinal cord injury (SCI) has not been elucidated. In our study, we evaluated the recovery of motor function after SCI by BBB, observed neuronal apoptosis by western blot and TUNEL, observed the changes of neuronal inflammation by western blot and immunofluorescence staining, and observed the changes of motoneurons and spinal cord area in the anterior horn of the spinal cord via Nissl and HE staining. We found that wnt-3a could significantly promote the recovery of motor function, reduce the loss of motor neurons in the anterior horn of the spinal cord, promote the recovery of injured spinal cord tissue, inhibit neuronal apoptosis and inflammatory response, and ultimately promote neuronal function after SCI. However, when XAV939 inhibits the wnt/β-catenin signaling pathway, the neuroprotective effects of wnt-3a are also significantly inhibited. The above results together indicated that wnt-3a exerts its neuroprotective effect on after SCI via activating the wnt/β-catenin signaling pathway.

Synergistic Pharmacological Therapy to Modulate Glial Cells in Spinal Cord Injury

Current treatments for modulating the glial-mediated inflammatory response after spinal cord injury (SCI) have limited ability to improve recovery. This is quite likely due to the lack of a selective therapeutic approach acting on microgliosis and astrocytosis, the glia components most involved after trauma, while maximizing efficacy and minimizing side effects. A new nanogel that can selectively release active compounds in microglial cells and astrocytes is developed and characterized. The degree of selectivity and subcellular distribution of the nanogel is evaluated by applying an innovative super-resolution microscopy technique, expansion microscopy. Two different administration schemes are then tested in a SCI mouse model: in an early phase, the nanogel loaded with Rolipram, an anti-inflammatory drug, achieves significant improvement in the animal's motor performance due to the increased recruitment of microglia and macrophages that are able to localize the lesion. Treatment in the late phase, however, gives opposite results, with worse motor recovery because of the widespread degeneration. These findings demonstrate that the nanovector can be selective and functional in the treatment of the glial component in different phases of SCI. They also open a new therapeutic scenario for tackling glia-mediated inflammation after neurodegenerative events in the central nervous system.

Hydrogel-encapsulated extracellular vesicles for the regeneration of spinal cord injury

Spinal cord injury (SCI) is a critical neurological condition that may impair motor, sensory, and autonomous functions. At the cellular level, inflammation, impairment of axonal regeneration, and neuronal death are responsible for SCI-related complications. Regarding the high mortality and morbidity rates associated with SCI, there is a need for effective treatment. Despite advances in SCI repair, an optimal treatment for complete recovery after SCI has not been found so far. Therefore, an effective strategy is needed to promote neuronal regeneration and repair after SCI. In recent years, regenerative treatments have become a potential option for achieving improved functional recovery after SCI by promoting the growth of new neurons, protecting surviving neurons, and preventing additional damage to the spinal cord. Transplantation of cells and cells-derived extracellular vesicles (EVs) can be effective for SCI recovery. However, there are some limitations and challenges related to cell-based strategies. Ethical concerns and limited efficacy due to the low survival rate, immune rejection, and tumor formation are limitations of cell-based therapies. Using EVs is a helpful strategy to overcome these limitations. It should be considered that short half-life, poor accumulation, rapid clearance, and difficulty in targeting specific tissues are limitations of EVs-based therapies. Hydrogel-encapsulated exosomes have overcome these limitations by enhancing the efficacy of exosomes through maintaining their bioactivity, protecting EVs from rapid clearance, and facilitating the sustained release of EVs at the target site. These hydrogel-encapsulated EVs can promote neuroregeneration through improving functional recovery, reducing inflammation, and enhancing neuronal regeneration after SCI. This review aims to provide an overview of the current research status, challenges, and future clinical opportunities of hydrogel-encapsulated EVs in the treatment of SCI.

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.

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.

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.

The research landscape of immunology research in spinal cord injury from 2012 to 2022

Background

Spinal cord injury (SCI) is defined as traumatic damage to the spinal cord, affecting over three million patients worldwide, and there is still no treatment for the injured spinal cord itself. In recent years, immunology research on SCI has been published in various journals.

Methods

To systematically analyze the research hotspots and dynamic scientific developments of immunology research in SCI, we conducted a bibliometric and knowledge map analysis to help researchers gain a global perspective in this research field.

Results

The bibliometric study we completed included 1788 English-language papers published in 553 journals by 8861 authors from 1901 institutions in 66 countries/regions. Based on the references and keyword analysis, researchers in the past 10 years have mainly focused on the research directions of "monocyte chemoattractor protein 1," "nitric oxide," "pain," and "nitric oxide synthase" related to immunological research in SCI. However, with the development of other new directions such as "extracellular vesicles" (2019-2022), "Regenerative medicine" (2019-2022), "stromal cells" (2018-2022), "motor recovery" (2019-2022), and "glial activation" (2019-2022). Researchers prefer to study the application of regenerative strategies in SCI, the mechanism of extracellular vesicles in the development of SCI, the activation of spinal glial cells in SCI, and the pathways of motor recovery. This bibliometric analysis of immunology research in SCI summarizes the current status of this research field. The relationship between extracellular vesicles, regenerative medicine, stromal cells, motor recovery, and glial activation is currently a major research frontier. Further research and cooperation worldwide need to be enhanced.

Conclusion

We believe that our research can help researchers quickly grasp the current hotspot of immunology research in SCI and determine a new direction for future research.

Development and validation of a differentiation-related signature based on single-cell RNA sequencing data of immune cells in spinal cord injury

Background

After spinal cord injury (SCI), the native immune surveillance function of the central nervous system is activated, resulting in a substantial infiltration of immune cells into the affected tissue. While numerous studies have explored the transcriptome data following SCI and revealed certain diagnostic biomarkers, there remains a paucity of research pertaining the identification of immune subtypes and molecular markers related to the immune system post-spinal cord injury using single-cell sequencing data of immune cells.

Methods

The researchers conducted an analysis of spinal cord samples obtained at three time points (3,10, and 21 days) following SCI using the GSE159638 dataset. The SCI subsets were delineated through pseudo-time analysis, and differentiation related genes were identified after principal component analysis (PCA), cell clustering, and annotation techniques. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were employed to assess the differentiation-related genes (DRGs) across different subsets. The molecular subtypes of SCI were determined using consensus clustering analysis. To further explore and validate the correlation between the molecular subtypes and the immune microenvironment, the CIBERSORT algorithm was employed. High-value diagnostic gene markers were identified using LASSO regression, and their diagnostic sensitivity was assessed using receiver operating characteristic curves (ROC) and quantitative real-time polymerase chain reaction (qRT-PCR).

Results

Three SCI subsets were obtained, and differentiation-related genes were characterized. Within these subsets, two distinct molecular subtypes, namely C1 and C2, were identified. These subtypes demonstrated significant variations in terms of immune cell infiltration levels and the expression of immune checkpoint genes. Through further analysis, three candidate biomarkers (C1qa, Lgals3 and Cd63) were identified and subsequently validated.

Conclusions

Our study revealed a diverse immune microenvironment in SCI samples, highlighting the potential significance of C1qa, Lgals3 and Cd63 as immune biomarkers for diagnosing SCI. Moreover, the identification of immune checkpoints corresponding to the two molecular subtypes suggests their potential as targets for immunotherapy to enhance SCI repair in future interventions.

LncRNA TSIX aggravates spinal cord injury by regulating the PI3K/AKT pathway via the miR-532-3p/DDOST axis

Long noncoding RNA (lncRNA)-X-inactive-specific transcript (TSIX) expression is upregulated in spinal cord tissues following spinal cord injury (SCI). However, the role of lncRNA-TSIX in SCI remains elusive. SCI animal model was established using C57BL/6 mice. LncRNA TSIX and miR-532-3p expression were determined using quantitative reverse transcription polymerase chain reaction (qRT-PCR). Apoptosis, cell proliferation, and migration were evaluated by transferase dUTP nick end labeling staining, CCK-8, and Transwell assays, respectively. The interaction of miR-532-3p with lncRNA TSIX and DDOST was explored via a dual-luciferase reporter system. Hematoxylin-eosin staining and the Basso, Beattie, and Bresnahan locomotor rating (BBB) scale were performed to investigate SCI progression. The expression of the lncRNA TSIX was found to be significantly upregulated in the serum of SCI patients and spinal cord tissues of SCI mice. The overexpression of lncRNA TSIX enhanced spinal cord neural stem cell (SC-NSC) proliferation and migration in vitro while inhibiting apoptosis and inflammatory cell infiltration in vivo. Moreover, lncRNA TSIX acted as a molecular sponge for miR-532-3p, and the knockdown of miR-532-3p promoted proliferation and migration and inhibited apoptosis of SC-NSCs. Moreover, DDOST was found to be the downstream target of miR-532-3p, and DDOST overexpression showed a similar effect as miR-532-3p silencing on the proliferation, migration, and apoptosis of SC-NSCs. Furthermore, we found that lncRNA TSIX overexpression promoted the activation of the PI3K/AKT signaling pathway. LncRNA TSIX aggravates SCI by regulating the PI3K/AKT pathway via the miR-532-3p/DDOST axis, indicating potential applications for targeted therapy of SCI regeneration.

Bibliometric analysis of stem cells for spinal cord injury: current status and emerging frontiers

Background: This study aimed to conduct a bibliometric analysis of the literature on stem cell therapy for spinal cord injury to visualize the research status, identify hotspots, and explore the development trends in this field. Methods: We searched the Web of Science Core Collection database using relevant keywords ("stem cells" and "spinal cord injury") and retrieved the published literature between 2000 and 2022. Data such as journal title, author information, institutional affiliation, country, and keywords were extracted. Afterwards, we performed bibliometric analysis of the retrieved data using Bibliometrix, VOSviewer, and CiteSpace. Results: A total of 5375 articles related to stem cell therapy for spinal cord injury were retrieved, and both the annual publication volume and the cumulative publication volume showed an upward trend. neural regeneration research was the journal with the most publications and the fastest cumulative publication growth (162 articles), Okano Hideyuki was the author with the highest number of publications and citations (114 articles), Sun Yat-sen University was the institution with the highest number of publications (420 articles), and China was the country with the highest number of publications (5357 articles). However, different authors, institutions, and countries need to enhance their cooperation in order to promote the generation of significant academic achievements. Current research in this field has focused on stem cell transplantation, neural regeneration, motor function recovery, exosomes, and tissue engineering. Meanwhile, future research directions are primarily concerned with the molecular mechanisms, safety, clinical trials, exosomes, scaffolds, hydrogels, and inflammatory responses of stem cell therapy for spinal cord injuries. Conclusion: In summary, this study provided a comprehensive analysis of the current research status and frontiers of stem cell therapy for spinal cord injury. The findings provide a foundation for future research and clinical translation efforts of stem cell therapy in this field.

Gonadotropin-releasing hormone and growth hormone act as anti-inflammatory factors improving sensory recovery in female rats with thoracic spinal cord injury

The potential for novel applications of classical hormones, such as gonadotropin-releasing hormone (GnRH) and growth hormone (GH), to counteract neural harm is based on their demonstrated neurotrophic effects in both in vitro and in vivo experimental models and a growing number of clinical trials. This study aimed to investigate the effects of chronic administration of GnRH and/or GH on the expression of several proinflammatory and glial activity markers in damaged neural tissues, as well as on sensory recovery, in animals submitted to thoracic spinal cord injury (SCI). Additionally, the effect of a combined GnRH + GH treatment was examined in comparison with single hormone administration. Spinal cord damage was induced by compression using catheter insufflation at thoracic vertebrae 10 (T10), resulting in significant motor and sensory deficits in the hindlimbs. Following SCI, treatments (GnRH, 60 μg/kg/12 h, IM; GH, 150 μg/kg/24 h, SC; the combination of both; or vehicle) were administered during either 3 or 5 weeks, beginning 24 h after injury onset and ending 24 h before sample collection. Our results indicate that a chronic treatment with GH and/or GnRH significantly reduced the expression of proinflammatory (IL6, IL1B, and iNOS) and glial activity (Iba1, CD86, CD206, vimentin, and GFAP) markers in the spinal cord tissue and improved sensory recovery in the lesioned animals. Furthermore, we found that the caudal section of the spinal cord was particularly responsive to GnRH or GH treatment, as well as to their combination. These findings provide evidence of an anti-inflammatory and glial-modulatory effect of GnRH and GH in an experimental model of SCI and suggest that these hormones can modulate the response of microglia, astrocytes, and infiltrated immune cells in the spinal cord tissue following injury.

Neuron-Derived Exosomes Promote the Recovery of Spinal Cord Injury by Modulating Nerve Cells in the Cellular Microenvironment of the Lesion Area

During spinal cord injury (SCI), the homeostasis of the cellular microenvironment in the injured area is seriously disrupted, which makes it extremely difficult for injured neurons with regenerative ability to repair, emphasizing the importance of restoring the cellular microenvironment at the injury site. Neurons interact closely with other nerve cells in the central nervous system (CNS) and regulate these cells. However, the specific mechanisms by which neurons modulate the cellular microenvironment remain unclear. Exosomes were isolated from the primary neurons, and their effects on astrocytes, microglia, oligodendrocyte progenitor cells (OPCs), neurons, and neural stem cells were investigated by quantifying the expression of related proteins and mRNA. A mouse SCI model was established, and neuron-derived exosomes were injected into the mice by the caudal vein to observe the recovery of motor function in mice and the changes in the nerve cells in the lesion area. Neuron-derived exosomes could reverse the activation of microglia and astrocytes and promote the maturation of OPCs in vivo and in vitro. In addition, neuron-derived exosomes promoted neurite outgrowth of neurons and the differentiation of neural stem cells into neurons. Moreover, our experiments showed that neuron-derived exosomes enhanced motor function recovery and nerve regeneration in mice with SCI. Our findings highlight that neuron-derived exosomes could promote the repair of the injured spinal cord by regulating the cellular microenvironment of neurons and could be a promising treatment for spinal cord injury.

Multiple mechanisms of curcumin targeting spinal cord injury

Spinal cord injury (SCI) is an irreversible disease process with a high disability and mortality rate. After primary spinal cord injury, the secondary injury may occur in sequence, which is composed of ischemia and hypoxia, excitotoxicity, calcium overload, oxidative stress and inflammation, resulting in massive death of parenchymal cells in the injured area, followed by the formation of syringomyelia. Effectively curbing the process of secondary injury can promote nerve repair and improve functional prognosis. As the main active ingredient in turmeric, curcumin can play an important role in reducing inflammation and oxidation, protecting the neurons, and ultimately reducing spinal cord injury. This article reviews the effects of curcumin on the repair of nerve injury, with emphasis on the various mechanisms by which curcumin promotes the treatment of spinal cord injury.

Targeting Underlying Inflammation in Carcinoma Is Essential for the Resolution of Depressiveness

In modern clinical practice and research on behavioral changes in patients with oncological problems, there are several one-sided approaches to these problems. Strategies for early detection of behavioral changes are considered, but they must take into account the specifics of the localization and phase in the course and treatment of somatic oncological disease. Behavioral changes, in particular, may correlate with systemic proinflammatory changes. In the up-to-date literature, there are a lot of useful pointers on the relationship between carcinoma and inflammation and between depression and inflammation. This review is intended to provide an overview of these similar underlying inflammatory disturbances in both oncological disease and depression. The specificities of acute and chronic inflammation are considered as a basis for causal current and future therapies. Modern therapeutic oncology protocols may also cause transient behavioral changes, so assessment of the quality, quantity, and duration of behavioral symptoms is necessary to prescribe adequate therapy. Conversely, antidepressant properties could be used to ameliorate inflammation. We will attempt to provide some impetus and present some unconventional potential treatment targets related to inflammation. It is certain that only an integrative oncology approach is justifiable in modern patient treatment.

[Experimental study on the repair of spinal cord injury by conducting hydrogel loaded with tetramethylpyrazine sustained-release microparticles]

Objective

To investigate the neuroprotective effect of conducting hydrogel loaded with tetramethylpyrazine sustained-release microparticles (hereinafter referred to as "TGTP hydrogel") on spinal cord injury rats.

Methods

Forty-eight adult female Sprague Dawley rats were randomly divided into 4 groups: sham operation group (group A), model group (group B), conductive hydrogel group (group C), and TGTP hydrogel group (group D), with 12 rats in each group. Only laminectomy was performed in group A, and complete spinal cord transection was performed in groups B, C, and D. Basso-Bettie-Bresnahan (BBB) score was used to evaluate the recovery of hind limb motor function of each group before modeling and at 1, 3, 7, 14, and 28 days after modeling, respectively. At 28 days after modeling, the rats were sacrificed for luxol fast blue (LFB) staining to detect myelin regeneration. Nissl staining was used to detect the survival of neurons. Immunohistochemical staining was used to evaluate the expression of inflammation-related factors [nuclear factor кB (NF-кB), tumor necrosis factor α (TNF-α), and interleukin 10 (IL-10)]. Immunofluorescence staining and Western blot were used to evaluate the expression of neurofilament 200 (NF200).

Rseults

BBB scores of group A were significantly better than those of the other three groups at all time points after modeling (P<0.05); at 14 and 28 days after modeling, there was no significant difference in BBB scores between groups C and D (P>0.05), but the BBB score of group D was significantly better than that of group B (P<0.05). LFB staining and Nissl staining showed that the structure of neurons and myelin in group A was intact, and the myelin integrity and survival number of neurons in group D were significantly better than those in groups B and C. Immunohistochemical staining showed that the absorbency (A) value of NF-кB and TNF-α in group A were significantly lower than those in groups B and C (P<0.05), the A value of IL-10 was significantly higher than that in the other three groups (P<0.05); the A value of NF-κB in group D was significantly lower than that in groups B and C, the A value of TNF-α in group D was significantly lower than that in group B, while the A value of IL-10 in group D was significantly higher than that in group B (P<0.05). Immunofluorescence staining showed that the structure of neurons and nerve fibers in group A was clear and the fluorescence intensity was high. The fluorescence intensity of NF200 in group D was higher than that in groups B and C, and some nerve fibers could be seen. Western blot analysis showed that the relative expression of NF200 in group A was the highest, and the relative expression of NF200 in group D was significantly higher than that in groups B and C (P<0.05).

Conclusion

The TGTP hydrogel can effectively promote the recovery of motor function in rats with spinal cord injury, and its mechanism may be related to the regulation of inflammatory response.