The Syvn1 inhibits neuronal cell ferroptosis by activating Stat3/Gpx4 axis in rat with spinal cord injury.

Spinal cord injury (SCI) leads to secondary neuronal death, which severely impedes recovery of motor function. Therefore, prevention of neuronal cell death after SCI is an important strategy. Ferroptosis, a new form of cell death discovered in recent years, has been shown to be involved in the regulation of SCI. However, the role and potential mechanisms of ferroptosis in secondary SCI are not fully understood. In this study, we report that the E3 ubiquitin ligase Syvn1 suppresses ferroptosis and promotes functional recovery from SCI in vitro and in vivo. Mechanistically, screened with bioinformatics, immunoprecipitation, and mass spectrometry, we identified Stat3, a transcription factor that induces the expression of the ferroptosis inhibitor Gpx4, as a substrate of Syvn1. Furthermore, we identified neurons as the primary cellular source of Syvn1 signalling. Moreover, we determined the binding domains of Syvn1 and Stat3 in HEK 293 T cells using full-length proteins and a series of truncated Flag-tagged and Myc-tagged fragments. Furthermore, we created the cell and animal models with silencing or overexpression of Syvn1 and Stat3 and found that Syvn1 inhibits neuronal ferroptosis by stabilizing Stat3, which subsequently activates the ferroptosis regulator Gpx4 in SCI. In summary, the Syvn1-mediated Stat3/Gpx4 signalling axis attenuates neuronal ferroptosis, reduces neuronal death, and promotes SCI repair. Therefore, our findings provide potential new targets and intervention strategies for the treatment of SCI.

USP3 promotes osteosarcoma progression via deubiquitinating EPHA2 and activating the PI3K/AKT signaling pathway.

Ubiquitin-specific protease 3 (USP3) plays an important role in the progression of various tumors. However, the role of USP3 in osteosarcoma (OS) remains poorly understood. The aim of this study was to explore the biological function of USP3 in OS and the underlying molecular mechanism. We found that OS had higher USP3 expression compared with that of normal bone tissue, and high expression of USP3 was associated with poor prognosis in patients with OS. Overexpression of USP3 significantly increased OS cell proliferation, migration, and invasion. Mechanistically, USP3 led to the activation of the PI3K/AKT signaling pathway in OS by binding to EPHA2 and then reducing its protein degradation. Notably, the truncation mutant USP3-F2 (159-520) interacted with EPHA2, and amino acid 203 was found to play an important role in this process. And knockdown of EPHA2 expression reversed the pro-tumour effects of USP3-upregulating. Thus, our study indicates the USP3/EPHA2 axis may be a novel potential target for OS treatment.

Risk Factors and Nomogram for Postoperative Pulmonary Infection in Patients with Cervical Spinal Cord Injury.

OBJECTIVE: To identify the risk factors for developing postoperative pulmonary infection in patients with acute cervical spinal cord injury (CSCI), and to develop a nomogram prediction model. METHODS: Patients with CSCI who were admitted to 3 different medical centers between July 2011 and July 2021 were included in this study. All patients underwent cervical spine surgery. Data for patients admitted to the first 2 centers were included in a training set to establish the nomogram prediction model, and data for patients admitted to the third center were included in a validation set to externally verify the efficacy of the prediction model. For the training set, patients were divided into an infected group and a noninfected group (control group). Independent risk factors for postoperative pulmonary infection in patients with CSCI were identified by univariate and multivariate logistic regression analyses. Additionally, a nomogram prediction model was developed and validated based on the risk factors. RESULTS: A total of 689 patients were enrolled, including 574 for the training set and 115 for the validation set. Of the patients included for the training set, 144 developed pulmonary infection, with an incidence of 25.09%; 40 patients included for the validation set developed pulmonary infection (34.78%). Multivariate logistic regression analysis showed that age, American Spinal Injury Association grade, steroid pulse, high-level injury, smoking, multistage surgery, and operation duration were risk factors for the development of postoperative pulmonary infection in patients with CSCI. The area under the curve of the receiver operating characteristic curve of the model built by the training set was 0.905, and that of the receiver operating characteristic curve of the verification set was 0.917. The decision curve indicated that the model was in the range 1%-100%, and the predicted net benefit value of the model was high. CONCLUSIONS: Age, American Spinal Injury Association grade, steroid pulse, CSCI site, smoking history, number of surgical levels, and surgical duration are correlated with the development of postoperative pulmonary infection in patients with CSCI. The risk prediction model of postoperative pulmonary infection has a good prediction efficiency and accuracy.

Machine learning for the prediction of postoperative nosocomial pulmonary infection in patients with spinal cord injury.

PURPOSE: The purpose of this study was to establish the best prediction model for postoperative nosocomial pulmonary infection through machine learning (ML) and assist physicians to make accurate diagnosis and treatment decisions. METHODS: Patients with spinal cord injury (SCI) who admitted to a general hospital between July 2014 and April 2022 were included in this study. The data were segmented according to the ratio of seven to three, 70% were randomly selected to train the model, and the other 30% were used for testing. We used LASSO regression to screen the variables, and the selected variables were used in the construction of six different ML models. Shapley additive explanations and permutation importance were used to explain the output of the ML models. Finally, sensitivity, specificity, accuracy and area under receiver operating characteristic curve (AUC) were used as the evaluation index of the model. RESULTS: A total of 870 patients were enrolled in this study, of whom 98 (11.26%) developed pulmonary infection. Seven variables were used for ML model construction and multivariate logistic regression analysis. Among these variables, age, ASIA scale and tracheotomy were found to be the independent risk factors for postoperative nosocomial pulmonary infection in SCI patients. Meanwhile, the prediction model based on RF algorithm performed best in the training and test sets. (AUC = 0.721, accuracy = 0.664, sensitivity = 0.694, specificity = 0.656). CONCLUSION: Age, ASIA scale and tracheotomy were the independent risk factors of postoperative nosocomial pulmonary infection in SCI. The prediction model based on RF algorithm had the best performance.

Alpinetin inhibits neuroinflammation and neuronal apoptosis via targeting the JAK2/STAT3 signaling pathway in spinal cord injury.

BACKGROUND: A growing body of research shows that drug monomers from traditional Chinese herbal medicines have antineuroinflammatory and neuroprotective effects that can significantly improve the recovery of motor function after spinal cord injury (SCI). Here, we explore the role and molecular mechanisms of Alpinetin on activating microglia-mediated neuroinflammation and neuronal apoptosis after SCI. METHODS: Stimulation of microglia with lipopolysaccharide (LPS) to simulate neuroinflammation models in vitro, the effect of Alpinetin on the release of pro-inflammatory mediators in LPS-induced microglia and its mechanism were detected. In addition, a co-culture system of microglia and neuronal cells was constructed to assess the effect of Alpinetin on activating microglia-mediated neuronal apoptosis. Finally, rat spinal cord injury models were used to study the effects on inflammation, neuronal apoptosis, axonal regeneration, and motor function recovery in Alpinetin. RESULTS: Alpinetin inhibits microglia-mediated neuroinflammation and activity of the JAK2/STAT3 pathway. Alpinetin can also reverse activated microglia-mediated reactive oxygen species (ROS) production and decrease of mitochondrial membrane potential (MMP) in PC12 neuronal cells. In addition, in vivo Alpinetin significantly inhibits the inflammatory response and neuronal apoptosis, improves axonal regeneration, and recovery of motor function. CONCLUSION: Alpinetin can be used to treat neurodegenerative diseases and is a novel drug candidate for the treatment of microglia-mediated neuroinflammation.

Effect of screw tunnels on proximal femur strength after screw removal: A finite element analysis.

BACKGROUND: The presence of screw tunnels in the femoral neck is a problem for patients with proximal femoral fractures after removal of internal fixation. The question of how much does the existence of the screw tunnels affect the strength of the femur and whether the patient needs to be protected with an adjunctive device has been controversial. The objective of this finite element analysis was to determine (1) whether the screw tunnels affects normal weight bearing after removal of internal fixation of a proximal femur fracture, (2) which screw tunnels parameters affect the weight bearing capacity of the entire femur. HYPOTHESIS: The presence of the screw tunnels reduces the load-bearing capacity of the femur, and the arrangement, diameter and wall thickness of the screw tunnels affect the load-bearing capacity of the femur. MATERIALS AND METHODS: Twenty patients who underwent surgical treatment for proximal femur fracture at our hospital were included in the study. Computed tomography (CT) values of the screw tunnel wall in the femur after removal of internal fixations were analysed. Mimics v16.0 and Hypermesh v13.0 software programs were used to generate 3-dimensional (3D) tetrahedral finite element models of the proximal femur with different screw tunnel numbers, diameters, thicknesses, and arrangements. An acetabulum exerting a vertical pressure load of 600N on the femoral head was simulated and the force on various parts of the femur in each model was calculated. RESULTS: There was no difference in the Hounsfield Units of the tunnel walls and cortical bone of the proximal femur (893.48±61.28 vs. 926.34±58.43; p=0.091). In each of the 3D models, the cancellous bone was the first structure to reach maximal stress. The compressive strength of the femur decreased with increasing thickness of the screw tunnel wall and decreased with increasing tunnel diameter. The femoral neck model with the inverted triangle screw tunnel arrangement had the highest compressive strength. DISCUSSION: The femoral neck with screw tunnels can withstand day-to-day stress without special intervention. For femoral neck fractures fixed with cannulated screws, inverted triangle screws are recommended; For a single screw tunnel in the femoral neck, the larger the diameter of the femoral neck internal screw channel, the weaker the load-bearing capacity of the femur. LEVEL OF EVIDENCE: III; well-designed computational non-experimental study.

Aucubin promoted neuron functional recovery by suppressing inflammation and neuronal apoptosis in a spinal cord injury model.

BACKGROUND: Spinal cord injury (SCI) can cause severe motor impairment. Post-SCI treatment has focused primarily on secondary injury, with neuroinflammation and neuronal apoptosis as the primary therapeutic targets. Aucubin (Au), a Chinese herbal medicine, exerts anti-inflammatory and neuroprotective effects. The therapeutic effects of Aucubin in SCI have not been reported. METHODS: In this study, we carried out an in vivo SCI model and a series of in vitro experiments to explore the therapeutic effect of Aucubin. Western Blotting and immunofluorescence were used to study the effect of Aucubin on microglial polarization and neuronal apoptosis and its underlying mechanism. RESULTS: We found that Aucubin can promote axonal regeneration by reducing neuroinflammation and neuronal apoptosis, which is beneficial to motor recovery after spinal cord injury in rats. Our further in vitro experiments showed that Aucubin can activate the toll-like receptor 4 (TLR4)/myeloid differentiation protein-88 (MyD88)/IκBα/nuclear factor kappa B (NF-κB) signaling pathway to reduce neuroinflammation and reverse mitochondrial dysfunction to reduce neuronal apoptosis. CONCLUSIONS: In summary, these results suggest that Aucubin may ameliorate secondary injury after SCI by reducing neuroinflammation and neuronal apoptosis. Therefore, Au may be a promising post-SCI therapeutic drug.

A Bibliometric Analysis of Publications on Spinal Cord Injury Treatment With Glucocorticoids Using VOSviewer.

Background: Spinal cord injury (SCI) has devastating physical and social consequences for patients. Systemic administration of methylprednisolone (MP) at a higher dosage though can reduce neurological deficits following acute SCI. Still, this treatment regimen is controversial, owing to the apparent dose-related side effects and relatively minor improvement in neurological function. Therefore, this study aimed at the bibliometric analysis of published literature related to SCI treatment, which may lead to future research trends. Methods: The literature published relating to SCI and using glucocorticoids for its treatment between 1982 and 2022 was collected and scanned in the Web of Science collection database using the keywords glucocorticoid, dexamethasone, MP, corticosteroids, and SCI, followed by using VOSviewer for bibliometric analysis of these articles. Results: A total of 1,848 published articles and 7,448 authors on SCI and glucocorticoid usage were identified. The SCI total link strength accounts for 1,341, and MP for 762 has a strong link to neuroprotection and inflammation. The mean citation count for the top 20 most-cited articles was 682 (range: 358-1,828), where most of these were descriptive studies having focused on clinical features. The Journal of Neurotrauma was the highest-ranked journal with 6,010 citations. A total of 69 articles were published by Michael G Fehlings from the University of Toronto with 6,092 citations. The University of Toronto has published 90-related manuscripts with 7,632 citations. In contrast, 800 articles were published in the United States, with 39,633 citations and total link strength of 5,714. The second-ranked country was China, with 241 published articles and 3,403 citations. Conclusions: The research published on applying MP in treating SCI has increased with time. Although the United States has made a significant global contribution to this important field of research, it requires rigorous clinical trials designed to verify the therapeutic role of MP in SCI and its appropriate dosage to find solutions for neurological recovery.

The role of routine laboratory tests after unilateral total knee arthroplasty.

BACKGROUND: Recent studies suggest that routine laboratory tests are not required within 1 day after partial knee arthroplasty. In this study, we evaluated the utility of routine postoperative laboratory tests after initial unilateral total knee arthroplasty (TKA) in an Asian population. In addition, we explored risk factors associated with abnormal test results. METHODS: Clinical data of patients who underwent original unilateral TKA between 2015 and 2020 were retrospectively analyzed. Patient characteristics and laboratory test results were recorded. Multivariate binary logistic regression analysis was performed to identify risk factors associated with 3 abnormal laboratory results. RESULTS: A total of 713 patients, who underwent relevant laboratory tests within 3 days of TKA surgery, were enrolled. Among them, 8.1%, 9.9%, and 3.4% patients with anemia, hypoalbuminemia, and abnormal serum potassium levels required clinical intervention after surgery. Binary logistic regression analysis revealed that preoperative hemoglobin levels, estimated blood loss, and age were independent risk factors of postoperative blood transfusion in TKA patients. On the other hand, preoperative albumin levels, intraoperative blood loss, and operation time were risk factors associated with postoperative albumin supplementation. In addition, lower body mass index (BMI) and preoperative hypokalemia were potential risk factors of postoperative potassium supplementation. CONCLUSION: Considering that more than 90% of abnormal postoperative laboratory tests do not require clinical intervention, we believe that routine laboratory tests after surgery have little significance in patients with primary unilateral TKA. However, postoperative laboratory testing is necessary for patients with established risk factors.

A bioactive injectable self-healing anti-inflammatory hydrogel with ultralong extracellular vesicles release synergistically enhances motor functional recovery of spinal cord injury.

The repair and motor functional recovery after spinal cord injury (SCI) remains a worldwide challenge. The inflammatory microenvironment is one of main obstacles on inhibiting the recovery of SCI. Using mesenchymal stem cells (MSCs) derived extracellular vesicles to replace MSCs transplantation and mimic cell paracrine secretions provides a potential strategy for microenvironment regulation. However, the effective preservation and controlled release of extracellular vesicles in the injured spinal cord tissue are still not satisfied. Herein, we fabricated an injectable adhesive anti-inflammatory F127-polycitrate-polyethyleneimine hydrogel (FE) with sustainable and long term extracellular vesicle release (FE@EVs) for improving motor functional recovery after SCI. The orthotopic injection of FE@EVs hydrogel could encapsulate extracellular vesicles on the injured spinal cord, thereby synergistically induce efficient integrated regulation through suppressing fibrotic scar formation, reducing inflammatory reaction, promoting remyelination and axonal regeneration. This study showed that combining extracellular vesicles into bioactive multifunctional hydrogel should have great potential in achieving satisfactory locomotor recovery of central nervous system diseases.

Interpreting the Mechanisms by which Integrins Promote the Differentiation of Mesenchymal Stem Cells and Integrin Application Prospects.

Transmembrane integrin receptors represent a major component of cell-extracellular matrix (ECM) communications that mediate cellular biological activities, including proliferation and differentiation. Stem cells, especially mesenchymal stem cells (MSC), have rapidly emerged as promising therapies for various diseases. Dynamic links exist between extracellular and intracellular environments that profoundly influence the cellular activities via integrin receptors, such as cell morphology transformation and differentiation. Interpreting the roles of integrin receptors in the regulation of MSC differentiation may potentially lead to an amplified therapeutic effect. In this review, we summarize, for the first time, the potential mechanisms by which integrins promote MSC multilineage differentiation, including integrin downstream signaling cascades and the interactions between integrin and ion channels, the cytoskeleton, and nuclear mechanoresponses. Furthermore, we focus on the current state and future prospects of the application of integrins to promote cell differentiation.

Rea regulates microglial polarization and attenuates neuronal apoptosis via inhibition of the NF-κB and MAPK signalings for spinal cord injury repair.

Inflammation and neuronal apoptosis aggravate the secondary damage after spinal cord injury (SCI). Rehmannioside A (Rea) is a bioactive herbal extract isolated from Rehmanniae radix with low toxicity and neuroprotection effects. Rea treatment inhibited the release of pro-inflammatory mediators from microglial cells, and promoted M2 polarization in vitro, which in turn protected the co-cultured neurons from apoptosis via suppression of the NF-κB and MAPK signalling pathways. Furthermore, daily intraperitoneal injections of 80 mg/kg Rea into a rat model of SCI significantly improved the behavioural and histological indices, promoted M2 microglial polarization, alleviated neuronal apoptosis, and increased motor function recovery. Therefore, Rea is a promising therapeutic option for SCI and should be clinically explored.

Growth differentiation factor-5-gelatin methacryloyl injectable microspheres laden with adipose-derived stem cells for repair of disc degeneration.

Nucleus pulposus (NP) degeneration is the major cause of degenerative disc disease (DDD). This condition cannot be treated or attenuated by traditional open or minimally invasive surgical options. However, a combination of stem cells, growth factors (GFs) and biomaterials present a viable option for regeneration. Injectable biomaterials act as carriers for controlled release of GFs and deliver stem cells to target tissues through a minimally invasive approach. In this study, injectable gelatin methacryloyl microspheres (GMs) with controllable, uniform particle sizes were rapidly biosynthesized through a low-cost electrospraying method. The GMs were used as delivery vehicles for cells and GFs, and they exhibited good mechanical properties and biocompatibility and enhanced the in vitro differentiation of laden cells into NP-like phenotypes. Furthermore, this integrated system attenuated the in vivo degeneration of rat intervertebral discs, maintained NP tissue integrity and accelerated the synthesis of extracellular matrix. Therefore, this novel therapeutic system is a promising option for the treatment of DDD.

Duraplasty of PHBV/PLA/Col membranes promotes axonal regeneration by inhibiting NLRP3 complex and M1 macrophage polarization in rats with spinal cord injury.

Duraplasty after decompression decreases the lesion size and scar formation, promoting better functional recovery, but the underlying mechanism has not been clarified. Here, we fabricated a series of poly(hydroxybutyrate-co-hydroxyvalerate)/polylactic acid/collagen (PHBV/PLA/Col) membranes and cultured them with VSC4.1 motor neurons. The material characteristics and in vitro biological characteristics were evaluated. In the subcutaneous implantation test, PHBV/PLA/COl scaffolds supported the cellular infiltration, microvasculature formation, and decreased CD86-positive macrophage aggregation. Following contusion spinal cord injury at T10 in Sprague-Dawley rats, durotomy was performed with allograft dura mater or PHBV/PLA or PHBV/PLA/Col membranes. At 3 days post-injury, Western blot assay showed decreased the expression of the NLRP3, ASC, cleaved-caspase-1, IL-1ß, TNF-α, and CD86 expression but increased the expression of CD206. Immunofluorescence demonstrated that duraplasty with PHBV/PLA/Col membranes reduced the infiltration of CD86-positive macrophages in the lesion site, decreased the glial fibrillary acidic protein expression, and increased the expression of NF-200. Moreover, duraplasty with PHBV/PLA/Col membranes improved locomotor functional recovery at 8 weeks post-injury. Thus, duraplasty with PHBV/PLA/Col membranes decreased the glial scar formation and promoted axon growth by inhibiting inflammasome activation and modulating macrophage polarization in acute spinal cord injury.

Corilagin suppresses RANKL-induced osteoclastogenesis and inhibits oestrogen deficiency-induced bone loss via the NF-κB and PI3K/AKT signalling pathways.

Over-activated osteoclastogenesis, which is initiated by inflammation, has been implicated in osteoporosis. Corilagin, a natural compound extracted from various medicinal herbaceous plants, such as Cinnamomum cassia, has antioxidant and anti-inflammatory activities. We found that Corilagin suppressed osteoclast differentiation in a dose-dependent manner, significantly decreased osteoclast-related gene expression and impaired bone resorption by osteoclasts. Moreover, phosphorylation of members of the nuclear factor-kappaB (NF-κB) and PI3K/AKT signalling pathways was reduced by Corilagin. In a murine model of osteoporosis, Corilagin inhibited osteoclast functions in vivo and restored oestrogen deficiency-induced bone loss. In conclusion, our findings suggested that Corilagin inhibited osteoclastogenesis by down-regulating the NF-κB and PI3K/AKT signalling pathways, thus showing its potential possibility for the treatment of osteoporosis.

Gelatin Methacrylate (GelMA)-Based Hydrogels for Cell Transplantation: an Effective Strategy for Tissue Engineering.

Gelatin methacrylate (GelMA)-based hydrogels are gaining a great deal of attention as potentially implantable materials in tissue engineering applications because of their biofunctionality and mechanical tenability. Since different natural tissues respond differently to mechanical stresses, an ideal implanted material would closely match the mechanical properties of the target tissue. In this regard, applications employing GelMA hydrogels are currently limited by the low mechanical strength and biocompatibility of GelMA. Therefore, this review focuses on modifications made to GelMA hydrogels to make them more suitable for tissue engineering applications. A large number of reports detail rational synthetic processes for GelMA or describe the incorporation of various biomaterials into GelMA hydrogels to tune their various properties, e.g., physical strength, chemical properties, conductivity, and porosity, and to promote cell loading and accelerate tissue repair. A novel strategy for repairing tissue injuries, based on the transplantation of cell-loaded GelMA scaffolds, is examined and its advantages and challenges are summarized. GelMA-cell combinations play a critical and pioneering role in this process and could potentially accelerate the development of clinically relevant applications.

Integration of mesenchymal stem cell sheet and bFGF-loaded fibrin gel in knitted PLGA scaffolds favorable for tendon repair.

Tendon injuries are common and require a long time to heal, and are particularly associated with some adverse problems such as adhesion and rupture. Herein, we aim to develop new bioactive scaffolds endowed with stem cell sheets and growth factors to enable cell migration and proliferation favorable for tendon regeneration in situ. An exogenous basic fibroblast growth factor (bFGF)-loaded fibrin gel was firstly incorporated into the porous network of knitted poly(lactide-co-glycolide) (PLGA) scaffolds and then sheets of mesenchymal stem cells (MSCs) were also integrated into the scaffolds. It was shown that the pores in the knitted PLGA scaffold were readily filled with a complex network of fibrin fiber gel and the fibrin fibers were beneficial for the controlled release of bFGF over a long time period. After transplantation in a critical-size Achilles tendon defect model (7 mm) in the rat right hindlimb, gross observation revealed no immunologic incompatibility or rejection derived from the scaffold systems. It was observed that the MSC sheets contributed directly to tendon regeneration, and exerted an environment-modifying effect on the injuries in situ, consistent with the beneficial effect of bFGF. It was interesting that the knitted PLGA-fibrin gel scaffolds loaded with MSC sheets and bFGF showed the highest expression of tendon-related gene markers and outstanding repair efficacy, including appreciable biomechanical strength and native-like histological microstructures. Therefore, the integration of MSC sheets and bFGF into PLGA/bFGF-fibrin gel scaffolds may stimulate the proliferation and tenogenic differentiation of MSCs in situ and synergistically enhance the injured tendon reconstruction.