ROS-responsive nanoparticle delivery of ferroptosis inhibitor prodrug to facilitate mesenchymal stem cell-mediated spinal cord injury repair

Spinal cord injury (SCI) is a traumatic condition that results in impaired motor and sensory function. Ferroptosis is one of the main causes of neural cell death and loss of neurological function in the spinal cord, and ferroptosis inhibitors are effective in reducing inflammation and repairing SCI. Although human umbilical cord mesenchymal stem cells (Huc-MSCs) can ameliorate inflammatory microenvironments and promote neural regeneration in SCI, their efficacy is greatly limited by the local microenvironment after SCI. Therefore, in this study, we constructed a drug-release nanoparticle system with synergistic Huc-MSCs and ferroptosis inhibitor, in which we anchored Huc-MSCs by a Tz-A6 peptide based on the CD44-targeting sequence, and combined with the reactive oxygen species (ROS)-responsive drug nanocarrier mPEG-b-Lys-BECI-TCO at the other end for SCI repair. Meanwhile, we also modified the classic ferroptosis inhibitor Ferrostatin-1 (Fer-1) and synthesized a new prodrug Feborastatin-1 (Feb-1). The results showed that this treatment regimen significantly inhibited the ferroptosis and inflammatory response after SCI, and promoted the recovery of neurological function in rats with SCI. This study developed a combination therapy for the treatment of SCI and also provides a new strategy for the construction of a drug-coordinated cell therapy system.

Celastrol inhibits oligodendrocyte and neuron ferroptosis to promote spinal cord injury recovery

BACKGROUND

Spinal cord injury (SCI) is a traumatic injury to the central nervous system and can cause lipid peroxidation in the spinal cord. Ferroptosis, an iron-dependent programmed cell death, plays a key role in the pathophysiology progression of SCI. Celastrol, a widely used antioxidant drug, has potential therapeutic value for nervous system.

PURPOSE

To investigate whether celastrol can be a reliable candidate for ferroptosis inhibitor and the molecular mechanism of celastrol in repairing SCI by inhibiting ferroptosis.

METHODS

First, a rat SCI model was constructed, and the recovery of motor function was observed after treatment with celastrol. The regulatory effect of celastrol on ferroptosis pathway Nrf2-xCT-GPX4 was detected by Western blot and immunofluorescence. Finally, the ferroptosis model of neurons and oligodendrocytes was constructed in vitro to further verify the mechanism of inhibiting ferroptosis by celastrol.

RESULTS

Our results demonstrated that celastrol promoted the recovery of spinal cord tissue and motor function in SCI rats. Further in vitro and in vivo studies showed that celastrol significantly inhibited ferroptosis in neurons and oligodendrocytes and reduced the accumulation of ROS. Finally, we found that celastrol could inhibit ferroptosis by up-regulating the Nrf2-xCT-GPX4 axis to repair SCI.

CONCLUSION

Celastrol effectively inhibits ferroptosis after SCI by upregulating the Nrf2-xCT-GPX4 axis, reducing the production of lipid ROS, protecting the survival of neurons and oligodendrocytes, and improving the functional recovery.

ROS-mediated lysosomal membrane permeabilization and autophagy inhibition regulate bleomycin-induced cellular senescence

Bleomycin exhibits effective chemotherapeutic activity against multiple types of tumors, and also induces various side effects, such as pulmonary fibrosis and neuronal defects, which limit the clinical application of this drug. Macroautophagy/autophagy has been recently reported to be involved in the functions of bleomycin, and yet the mechanisms of their crosstalk remain insufficiently understood. Here, we demonstrated that reactive oxygen species (ROS) produced during bleomycin activation hampered autophagy flux by inducing lysosomal membrane permeabilization (LMP) and obstructing lysosomal degradation. Exhaustion of ROS with N-acetylcysteine relieved LMP and autophagy defects. Notably, we observed that LMP and autophagy blockage preceded the emergence of cellular senescence during bleomycin treatment. In addition, promoting or inhibiting autophagy-lysosome degradation alleviated or exacerbated the phenotypes of senescence, respectively. This suggests the alternation of autophagy activity is more a regulatory mechanism than a consequence of bleomycin-induced cellular senescence. Taken together, we reveal a specific role of bleomycin-induced ROS in mediating defects of autophagic degradation and further regulating cellular senescence in vitro and in vivo. Our findings, conversely, indicate the autophagy-lysosome degradation pathway as a target for modulating the functions of bleomycin. These provide a new perspective for optimizing bleomycin as a clinically applicable chemotherapeutics devoid of severe side-effects.Abbreviations: AT2 cells: type II alveolar epithelial cells; ATG7: autophagy related 7; bEnd.3: mouse brain microvascular endothelial cells; BNIP3L: BCL2/adenovirus E1B interacting protein 3-like; CCL2: C-C motif chemokine ligand 2; CDKN1A: cyclin dependent kinase inhibitor 1A; CDKN2A: cyclin dependent kinase inhibitor 2A; FTH1: ferritin heavy polypeptide 1; γ-H2AX: phosphorylated H2A.X variant histone; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; HUVEC: human umbilical vein endothelial cells; HT22: hippocampal neuronal cell lines; Il: interleukin; LAMP: lysosomal-associated membrane protein; LMP: lysosome membrane permeabilization; MTORC1: mechanistic target of rapamycin kinase complex 1; NAC: N-acetylcysteine; NCOA4: nuclear receptor coactivator 4; PI3K: phosphoinositide 3-kinase; ROS: reactive oxygen species; RPS6KB/S6K: ribosomal protein S6 kinase; SA-GLB1/β-gal: senescence-associated galactosidase, beta 1; SAHF: senescence-associated heterochromatic foci; SASP: senescence-associated secretory phenotype; SEC62: SEC62 homolog, preprotein translocation; SEP: superecliptic pHluorin; SQSTM1/p62: sequestosome 1; TFEB: transcription factor EB.

Protocol for the Chinese Real-World Evidence for Acute Spinal Cord Injury (ChiRES) study: a prospective, observational, multicentre cohort study of acute spinal cord injury

INTRODUCTION

Spinal cord injury (SCI) is a catastrophic event with devastating physical, social and occupational consequences for patients and their families. The number of patients with acute SCI in China continues to grow rapidly, but there have been no large prospective cohort studies of patients with acute SCI. This proposed study aims to establish a multicentre, extensive sample cohort of clinical data and biological samples of patients in China, which would aid the systematisation and standardisation of clinical research and treatment of acute SCI, thus reducing the heavy burden of acute SCI on patients and society.

METHODS AND ANALYSIS

The Chinese Real-World Evidence for Acute Spinal Cord Injury (ChiRES) study is an observational, multicentre cohort study of patients with acute SCI admitted to the Qilu Hospital of Shandong University and other participating centres with prospective collection of their clinical data and biological samples. We aim to recruit 2097 patients in this study. Demographics, disease history, emergency intervention information, motor and sensory examinations, surgical information, medication information and rehabilitation evaluation will be recorded. This will facilitate the development of a prediction model for complications and prognosis of patients with acute SCI and an evaluation of the current management of acute SCI. Among these variables, detailed information on surgical treatment will also be used to assess procedures for acute SCI treatment. Outcome measurements, including the International Standard for Neurological Classification of Spinal Cord Injury examinations, the occurrence of complications and death, will be performed repeatedly during follow-up. We will analyse imaging data and blood samples to develop SCI imaging markers and biomarkers.

ETHICS AND DISSEMINATION

This study protocol has been approved by the Medical Ethics Committee of the Qilu Hospital of Shandong University and all other participating centres. The findings will be disseminated in peer-reviewed journals and academic conferences.

New strategy to treat spinal cord injury: Nafamostat mesilate suppressed NLRP3-mediated pyroptosis during acute phase

Spinal cord injury (SCI) is a devastating condition for which effective clinical treatment is currently lacking. During the acute phase of SCI, myriad pathological changes give rise to subsequent secondary injury. The results of our previous studies indicated that treating rats post-SCI with nafamostat mesilate (NM) protected the blood-spinal cord barrier (BSCB) and exerted an antiapoptotic effect. However, the optimal dosage for mice with SCI and the underlying mechanisms potentially contributing to recovery, especially during the acute phase of SCI, have not been determined. In this study, we first determined the optimal dosage of NM for mice post-SCI (5 mg/kg/day). Subsequently, our RNA-seq findings revealed that NM has the potential to inhibit pyroptosis after SCI. These findings were further substantiated by subsequent Western blot (WB) and Immunofluorescence (IF) analyses in vivo. These results indicate that NM can alleviate NLRP3 (NOD-like receptor thermal protein domain associated protein 3)-mediated pyroptosis by modulating the NF-κB signaling pathway and reducing the protein expression levels of NIMA-related kinase 7 (NEK7) and cathepsin B (CTSB). In vitro experimental results supported our in vivo findings, revealing the effectiveness of NM in suppressing pyroptosis induced by adenosine triphosphate (ATP) and lipopolysaccharide (LPS) in BV2 cells. These results underscore the potential of NM to regulate NLRP3-mediated pyroptosis following SCI. Notably, compared with other synthetic compounds, NM exhibits greater versatility, suggesting that it is a promising clinical treatment option for SCI.

Epidemiological and clinical features, treatment status, and economic burden of traumatic spinal cord injury in China: a hospital-based retrospective study

Traumatic spinal cord injury is potentially catastrophic and can lead to permanent disability or even death. China has the largest population of patients with traumatic spinal cord injury. Previous studies of traumatic spinal cord injury in China have mostly been regional in scope; national-level studies have been rare. To the best of our knowledge, no national-level study of treatment status and economic burden has been performed. This retrospective study aimed to examine the epidemiological and clinical features, treatment status, and economic burden of traumatic spinal cord injury in China at the national level. We included 13,465 traumatic spinal cord injury patients who were injured between January 2013 and December 2018 and treated in 30 hospitals in 11 provinces/municipalities representing all geographical divisions of China. Patient epidemiological and clinical features, treatment status, and total and daily costs were recorded. Trends in the percentage of traumatic spinal cord injuries among all hospitalized patients and among patients hospitalized in the orthopedic department and cost of care were assessed by annual percentage change using the Joinpoint Regression Program. The percentage of traumatic spinal cord injuries among all hospitalized patients and among patients hospitalized in the orthopedic department did not significantly change overall (annual percentage change, -0.5% and 2.1%, respectively). A total of 10,053 (74.7%) patients underwent surgery. Only 2.8% of patients who underwent surgery did so within 24 hours of injury. A total of 2005 (14.9%) patients were treated with high-dose (≥ 500 mg) methylprednisolone sodium succinate/methylprednisolone (MPSS/MP); 615 (4.6%) received it within 8 hours. The total cost for acute traumatic spinal cord injury decreased over the study period (-4.7%), while daily cost did not significantly change (1.0% increase). Our findings indicate that public health initiatives should aim at improving hospitals' ability to complete early surgery within 24 hours, which is associated with improved sensorimotor recovery, increasing the awareness rate of clinical guidelines related to high-dose MPSS/MP to reduce the use of the treatment with insufficient evidence.

Multifunctional Conductive and Electrogenic Hydrogel Repaired Spinal Cord Injury via Immunoregulation and Enhancement of Neuronal Differentiation

Spinal cord injury (SCI) is a refractory neurological disorder. Due to the complex pathological processes, especially the secondary inflammatory cascade and the lack of intrinsic regenerative capacity, it is difficult to recover neurological function after SCI. Meanwhile, simulating the conductive microenvironment of the spinal cord reconstructs electrical neural signal transmission interrupted by SCI and facilitates neural repair. Therefore, a double-crosslinked conductive hydrogel (BP@Hydrogel) containing black phosphorus nanoplates (BP) is synthesized. When placed in a rotating magnetic field (RMF), the BP@Hydrogel can generate stable electrical signals and exhibit electrogenic characteristic. In vitro, the BP@Hydrogel shows satisfactory biocompatibility and can alleviate the activation of microglia. When placed in the RMF, it enhances the anti-inflammatory effects. Meanwhile, wireless electrical stimulation promotes the differentiation of neural stem cells (NSCs) into neurons, which is associated with the activation of the PI3K/AKT pathway. In vivo, the BP@Hydrogel is injectable and can elicit behavioral and electrophysiological recovery in complete transected SCI mice by alleviating the inflammation and facilitating endogenous NSCs to form functional neurons and synapses under the RMF. The present research develops a multifunctional conductive and electrogenic hydrogel for SCI repair by targeting multiple mechanisms including immunoregulation and enhancement of neuronal differentiation.

Re-analysis of single-cell RNA-seq data reveals the origin and roles of cycling myeloid cells

Cycling myeloid cells (CMCs) are often detected from various tissues using single-cell RNA sequencing (scRNA-seq) datasets, however, their research value was not noticed before. For the first time, our study preliminarily revealed the origin, differentiation, and roles of CMCs in physiological processes. Particularly, subgroup a of cycling myeloid cells (aCMCs) were conclusively identified as belonging to a specific cell type. In an active state, aCMCs rapidly proliferate during the early stages of an embryonic development. With an individual maturing, most aCMCs differentiate into specialized cells, while a small portion of them enter an inactive or dormant state. Under pathological conditions, aCMCs restore their proliferative and differentiation capacities via activation or revival. The present study has set the stage for future research on CMCs by linking them with progenitors of immune cells, and provided a crucial starting point to understand the origin, differentiation, and roles of CMCs in various physiological and pathological processes, particularly those related to traumatic injury, cancer, and pathogen infection, leading to develop targeted therapies or interventions.

Variability in the prevalence of depression among adults with chronic pain: UK Biobank analysis through clinical prediction models

BACKGROUND

The prevalence of depression among people with chronic pain remains unclear due to the heterogeneity of study samples and definitions of depression. We aimed to identify sources of variation in the prevalence of depression among people with chronic pain and generate clinical prediction models to estimate the probability of depression among individuals with chronic pain.

METHODS

Participants were from the UK Biobank. The primary outcome was a "lifetime" history of depression. The model's performance was evaluated using discrimination (optimism-corrected C statistic) and calibration (calibration plot).

RESULTS

Analyses included 24,405 patients with chronic pain (mean age 64.1 years). Among participants with chronic widespread pain, the prevalence of having a "lifetime" history of depression was 45.7% and varied (25.0-66.7%) depending on patient characteristics. The final clinical prediction model (optimism-corrected C statistic: 0.66; good calibration on the calibration plot) included age, BMI, smoking status, physical activity, socioeconomic status, gender, history of asthma, history of heart failure, and history of peripheral artery disease. Among participants with chronic regional pain, the prevalence of having a "lifetime" history of depression was 30.2% and varied (21.4-70.6%) depending on patient characteristics. The final clinical prediction model (optimism-corrected C statistic: 0.65; good calibration on the calibration plot) included age, gender, nature of pain, smoking status, regular opioid use, history of asthma, pain location that bothers you most, and BMI.

CONCLUSIONS

There was substantial variability in the prevalence of depression among patients with chronic pain. Clinically relevant factors were selected to develop prediction models. Clinicians can use these models to assess patients' treatment needs. These predictors are convenient to collect during daily practice, making it easy for busy clinicians to use them.

SP1/CTR1-mediated oxidative stress-induced cuproptosis in intervertebral disc degeneration

Intervertebral disc degeneration (IDD) is an age-related disease and is responsible for low back pain. Oxidative stress-induced cell death plays a fundamental role in IDD pathogenesis. Cuproptosis is a recently discovered form of programmed cell death dependent on copper availability. Whether cuproptosis is involved in IDD progression remains unknown. Herein, we established in vitro and in vivo models to investigate cuproptosis in IDD and the mechanisms by which oxidative stress interacts with copper sensitivity in nucleus pulposus cells (NPCs). We found that ferredoxin-1 (FDX1) content increased in both rat and human degenerated discs. Sublethal oxidative stress on NPCs led to increased FDX1 expression, tricarboxylic acid (TCA) cycle-related proteins lipoylation and aggregation, and cell death in the presence of Cu2+ at physiological concentrations, while FDX1 knockdown inhibited cell death. Since copper homeostasis is involved in copper-induced cytotoxicity, we investigated the role of copper transport-related proteins, including importer (CTR1) and efflux pumps (ATPase transporter, ATP7A, and ATP7B). CTR1 and ATP7A content increased under oxidative stress, and blocking CTR1 reduced oxidative stress/copper-induced TCA-related protein aggregation and cell death. Moreover, oxidative stress promoted the expression of specific protein 1 (SP1) and SP1-mediated CTR1 transcription. SP1 inhibition decreased cell death rates, preserved disc hydration, and alleviated tissue degeneration. This suggests that oxidative stress upregulates FDX1 expression and copper flux through promoting SP1-mediated CTR1 transcription, leading to increased TCA cycle-related protein aggregation and cuproptosis. This study highlights the importance of cuproptosis in IDD progression and provides a promising therapeutic target for IDD treatment.

Human umbilical cord mesenchymal stem cell-derived exosomes loaded into a composite conduit promote functional recovery after peripheral nerve injury in rats

Complete transverse injury of peripheral nerves is challenging to treat. Exosomes secreted by human umbilical cord mesenchymal stem cells are considered to play an important role in intercellular communication and regulate tissue regeneration. In previous studies, a collagen/hyaluronic acid sponge was shown to provide a suitable regeneration environment for Schwann cell proliferation and to promote axonal regeneration. This three-dimensional (3D) composite conduit contains a collagen/hyaluronic acid inner sponge enclosed in an electrospun hollow poly (lactic-co-glycolic acid) tube. However, whether there is a synergy between the 3D composite conduit and exosomes in the repair of peripheral nerve injury remains unknown. In this study, we tested a comprehensive strategy for repairing long-gap (10 mm) peripheral nerve injury that combined the 3D composite conduit with human umbilical cord mesenchymal stem cell-derived exosomes. Repair effectiveness was evaluated by sciatic functional index, sciatic nerve compound muscle action potential recording, recovery of muscle mass, measuring the cross-sectional area of the muscle fiber, Masson trichrome staining, and transmission electron microscopy of the regenerated nerve in rats. The results showed that transplantation of the 3D composite conduit loaded with human umbilical cord mesenchymal stem cell-derived exosomes promoted peripheral nerve regeneration and restoration of motor function, similar to autograft transplantation. More CD31-positive endothelial cells were observed in the regenerated nerve after transplantation of the loaded conduit than after transplantation of the conduit without exosomes, which may have contributed to the observed increase in axon regeneration and distal nerve reconnection. Therefore, the use of a 3D composite conduit loaded with human umbilical cord mesenchymal stem cell-derived exosomes represents a promising cell-free therapeutic option for the treatment of peripheral nerve injury.

PGC1α-Inducing Senomorphic Nanotherapeutics Functionalized with NKG2D-Overexpressing Cell Membranes for Intervertebral Disc Degeneration

Cellular senescence is a significant contributor to intervertebral disc aging and degeneration. However, the application of senotherapies, such as senomorphics targeting senescence markers and the senescence-associated secretory phenotype (SASP), remains limited due to challenges in precise delivery. Given that the natural killer group 2D (NKG2D) ligands are increased on the surface of senescent nucleus pulposus (NP) cells, the NKG2D-overexpressing NP cell membranes (NNPm) are constructed, which is expected to achieve a dual targeting effect toward senescent NP cells based on homologous membrane fusion and the NKG2D-mediated immunosurveillance mechanism. Then, mesoporous silica nanoparticles carrying a peroxisome proliferator-activated receptor-ɣ coactivator 1α (PGC1α)inducer (SP) are coated with NNPm (SP@NNPm) and it is found that SP@NNPm selectively targets senescent NP cells, and the SP cores exhibit pH-responsive drug release. Moreover, SP@NNPm effectively induces PGC1α-mediated mitochondrial biogenesis and mitigates senescence-associated markers induced by oxidative stress and the SASP, thereby alleviating puncture-induced senescence and disc degeneration. This dual-targeting nanotherapeutic system represents a novel approach to delivery senomorphics for disc degeneration treatment.

Piezo1 channel exaggerates ferroptosis of nucleus pulposus cells by mediating mechanical stress-induced iron influx

To date, several molecules have been found to facilitate iron influx, while the types of iron influx channels remain to be elucidated. Here, Piezo1 channel was identified as a key iron transporter in response to mechanical stress. Piezo1-mediated iron overload disturbed iron metabolism and exaggerated ferroptosis in nucleus pulposus cells (NPCs). Importantly, Piezo1-induced iron influx was independent of the transferrin receptor (TFRC), a well-recognized iron gatekeeper. Furthermore, pharmacological inactivation of Piezo1 profoundly reduced iron accumulation, alleviated mitochondrial ROS, and suppressed ferroptotic alterations in stimulation of mechanical stress. Moreover, conditional knockout of Piezo1 (Col2a1-CreERT Piezo1flox/flox) attenuated the mechanical injury-induced intervertebral disc degeneration (IVDD). Notably, the protective effect of Piezo1 deficiency in IVDD was dampened in Piezo1/Gpx4 conditional double knockout (cDKO) mice (Col2a1-CreERT Piezo1flox/flox/Gpx4flox/flox). These findings suggest that Piezo1 is a potential determinant of iron influx, indicating that the Piezo1-iron-ferroptosis axis might shed light on the treatment of mechanical stress-induced diseases.

Magnetic Nanoparticles and Methylprednisolone Based Physico-Chemical Bifunctional Neural Stem Cells Delivery System for Spinal Cord Injury Repair

Neural stem cells (NSCs) transplantation is an attractive and promising treatment strategy for spinal cord injury (SCI). Various pathological processes including the severe inflammatory cascade and difficulty in stable proliferation and differentiation of NSCs limit its application and translation. Here, a novel physico-chemical bifunctional neural stem cells delivery system containing magnetic nanoparticles (MNPs and methylprednisolone (MP) is designed to repair SCI, the former regulates NSCs differentiation through magnetic mechanical stimulation in the chronic phase, while the latter alleviates inflammatory response in the acute phase. The delivery system releases MP to promote microglial M2 polarization, inhibit M1 polarization, and reduce neuronal apoptosis. Meanwhile, NSCs tend to differentiate into functional neurons with magnetic mechanical stimulation generated by MNPs in the static magnetic field, which is related to the activation of the PI3K/AKT/mTOR pathway. SCI mice achieve better functional recovery after receiving NSCs transplantation via physico-chemical bifunctional delivery system, which has milder inflammation, higher number of M2 microglia, more functional neurons, and axonal regeneration. Together, this bifunctional NSCs delivery system combined physical mechanical stimulation and chemical drug therapy is demonstrated to be effective, which provides new treatment insights into clinical transformation of SCI repair.

Targeted Repair of Spinal Cord Injury Based on miRNA-124-3p-Loaded Mesoporous Silica Camouflaged by Stem Cell Membrane Modified with Rabies Virus Glycoprotein

Spinal cord injury (SCI) has no effective treatment modalities. It faces a significant global therapeutical challenge, given its features of poor axon regeneration, progressive local inflammation, and inefficient systemic drug delivery due to the blood-spinal cord barrier (BSCB). To address these challenges, a new nano complex that achieves targeted drug delivery to the damaged spinal cord is proposed, which contains a mesoporous silica nanoparticle core loaded with microRNA and a cloaking layer of human umbilical cord mesenchymal stem cell membrane modified with rabies virus glycoprotein (RVG). The nano complex more readily crosses the damaged BSCB with its exosome-resembling properties, including appropriate size and a low-immunogenic cell membrane disguise and accumulates in the injury center because of RVG, where it releases abundant microRNAs to elicit axon sprouting and rehabilitate the inflammatory microenvironment. Culturing with nano complexes promotes axonal growth in neurons and M2 polarization in microglia. Furthermore, it showed that SCI mice treated with this nano complex by tail vein injection display significant improvement in axon regrowth, microenvironment regulation, and functional restoration. The efficacy and biocompatibility of the targeted delivery of microRNA by nano complexes demonstrate their immense potential as a noninvasive treatment for SCI.

Long-Acting Heterodimeric Paclitaxel-Idebenone Prodrug-Based Nanomedicine Promotes Functional Recovery after Spinal Cord Injury

After spinal cord injury (SCI), successive systemic administration of microtubule-stabilizing agents has been shown to promote axon regeneration. However, this approach is limited by poor drug bioavailability, especially given the rapid restoration of the blood-spinal cord barrier. There is a pressing need for long-acting formulations of microtubule-stabilizing agents in treating SCI. Here, we conjugated the antioxidant idebenone with microtubule-stabilizing paclitaxel to create a heterodimeric paclitaxel-idebenone prodrug via an acid-activatable, self-immolative ketal linker and then fabricated it into chondroitin sulfate proteoglycan-binding nanomedicine, enabling drug retention within the spinal cord for at least 2 weeks and notable enhancement in hindlimb motor function and axon regeneration after a single intraspinal administration. Additional investigations uncovered that idebenone can suppress the activation of microglia and neuronal ferroptosis, thereby amplifying the therapeutic effect of paclitaxel. This prodrug-based nanomedicine simultaneously accomplishes neuroprotection and axon regeneration, offering a promising therapeutic strategy for SCI.

Tolerant and Rapid Endochondral Bone Regeneration Using Framework-Enhanced 3D Biomineralized Matrix Hydrogels

Tissue-engineered bone has emerged as a promising alternative for bone defect repair due to the advantages of regenerative bone healing and physiological functional reconstruction. However, there is very limited breakthrough in achieving favorable bone regeneration due to the harsh osteogenic microenvironment after bone injury, especially the avascular and hypoxic conditions. Inspired by the bone developmental mode of endochondral ossification, a novel strategy is proposed for tolerant and rapid endochondral bone regeneration using framework-enhanced 3D biomineralized matrix hydrogels. First, it is meticulously designed 3D biomimetic hydrogels with both hypoxic and osteoinductive microenvironment, and then integrated 3D-printed polycaprolactone framework to improve their mechanical strength and structural fidelity. The inherent hypoxic 3D matrix microenvironment effectively activates bone marrow mesenchymal stem cells self-regulation for early-stage chondrogenesis via TGFβ/Smad signaling pathway due to the obstacle of aerobic respiration. Meanwhile, the strong biomineralized microenvironment, created by a hybrid formulation of native-constitute osteogenic inorganic salts, can synergistically regulate both bone mineralization and osteoclastic differentiation, and thus accelerate the late-stage bone maturation. Furthermore, both in vivo ectopic osteogenesis and in situ skull defect repair successfully verified the high efficiency and mechanical maintenance of endochondral bone regeneration mode, which offers a promising treatment for craniofacial bone defect repair.

Low back pain-driven inpatient stays in the United States: a nationwide repeated cross-sectional analysis

BACKGROUND

Low back pain (LBP)-driven inpatient stays are resource-intensive and costly, yet data on contemporary national trends are limited.

MATERIALS AND METHODS

This study used repeated cross-sectional analyses through a nationally representative sample (US National Inpatient Sample, 2016-2019). Outcomes included the rate of LBP-driven inpatient stays; the resource utilization (the proportion of receiving surgical treatments and hospital costs) and prognosis (hospital length of stay and the proportion of nonroutine discharge) among LBP-driven inpatient stays. LBP was classified as overall, nonspecific, and specific (i.e. cancer, cauda equina syndrome, vertebral infection, vertebral compression fracture, axial spondyloarthritis, radicular pain, and spinal canal stenosis). Analyses were further stratified by age, sex, and race/ethnicity.

RESULTS

292 987 LBP-driven inpatient stays (weighted number: 1 464 690) were included, with 269 080 (91.8%) of these for specific LBP and 23 907 (8.2%) for nonspecific LBP. The rate of LBP-driven inpatient stays varied a lot across demographic groups and LBP subtypes (e.g. for overall LBP, highest for non-Hispanic White 180.4 vs. lowest for non-Hispanic Asian/Pacific Islander 42.0 per 100 000 population). Between 2016 and 2019, the rate of nonspecific LBP-driven inpatient stays significantly decreased (relative change: 46.9%); however, substantial variations were found within subcategories of specific LBP-significant increases were found for vertebral infection (relative change: 17.2%), vertebral compression fracture (relative change: 13.4%), and spinal canal stenosis (relative change: 19.9%), while a significant decrease was found for radicular pain (relative change: 12.6%). The proportion of receiving surgical treatments also varied a lot (e.g. for overall LBP, highest for non-Hispanic White 74.4% vs. lowest for non-Hispanic Asian/Pacific Islander 62.8%), and significantly decreased between 2016 and 2019 (e.g. for nonspecific LBP, relative change: 28.6%). Variations were also observed for other outcomes.

CONCLUSIONS

In the US, the burden of LBP-driven inpatient stays (i.e. rates of LBP-driven inpatient stays, resource utilization, and prognosis among LBP-driven inpatient stays) is enormous. More research is needed to understand why the burden varies considerably according to the LBP subtype (i.e. nonspecific and specific LBP as well as subcategories of specific LBP) and the subpopulation concerned (i.e. stratified by age, sex, and race/ethnicity).

Epidemiological age-based differences in traumatic spinal cord injury patients: A multicenter study based on 13,334 inpatients

CONTEXT

Compared with younger traumatic spinal cord injury (TSCI) patients, the elderly had longer delays in admission to surgery, higher proportion of incomplete injury, and longer hospital stays. However, in China, the country with the largest number of TSCI patients, there have been no large-scale reports on their age differences.

OBJECTIVES

To explore the age-based differences among TSCI inpatients, focusing on the demographic and clinical characteristics, treatment status, and economic burden.

METHODS

We collected the medical records of 13,334 inpatients with TSCI in the 30 hospitals of China, from January 1, 2013 to December 31, 2018. Trends are expressed as annual percentage changes (APCs) and 95% confidence intervals (CIs).

RESULTS

A total of 13,334 inpatients were included. Both the number and proportion of the elderly showed an increasing trend. The APC of the number and proportion in patients ≥85 years were 39.5% (95% CI, 14.3 to 70.3; P < 0.01) and 30.5% (95% CI, 8.6 to 56.9; P < 0.01), respectively. Younger patients were more likely to undergo decompression surgery, and older patients were more likely to receive high-dose methylprednisolone sodium succinate/methylprednisolone (MPSS/MP). Of the patients ≥85 years, none underwent decompression surgery within 8 h, and only 1.4% received a high dose of MPSS/MP within 8 h after injury. Elderly patients had lower hospitalization costs than younger. The total and daily medical costs during hospitalization of patients ≥85 years were 8.06 ± 18.80 (IQR: 5.79) and 0.61 ± 0.73 (IQR: 0.55) thousands dollars, respectively.

CONCLUSIONS

As the first study to focus on age differences of TSCI patients in China, this study found many differences, in demographic and clinical characteristics, treatment status, and economic costs, between older and younger TSCI patients. The number and proportion of elderly patients increased, and the rate of early surgery for elderly patients is low.

Enzymatically Bioactive Nucleus Pulposus Matrix Hydrogel Microspheres for Exogenous Stem Cells Therapy and Endogenous Repair Strategy to Achieve Disc Regeneration

Exogenous stem cell therapy and endogenous repair has shown great potential in intervertebral disc regeneration. However, limited nutrients and accumulation of lactate largely impair the survival and regenerative capacity of implanted stem cells and endogenous nucleus pulposus cells (NPCs). Herein, an injectable hydrogel microsphere (LMGDNPs) have been developed by immersing lactate oxidase (LOX)-manganese dioxide (MnO2 ) nanozyme (LM) into glucose-enriched decellularized nucleus pulposus hydrogel microspheres (GDNPs) through a microfluidic system. LMGDNPs showed a delayed release profile of LOX and satisfactory enzymatic capacity in consuming lactate. Mesenchymal stem cells (MSCs) plated on LMGDNPs exhibited better cell viability than cells on GelMA and decellularized nucleus pulposus microspheres (DNP) and showed a obviously increased NPCs phenotype. LMGDNPs prevented MSCs and NPCs death and promoted extracellular matrix synthesis by exhausting lactate. It is determined that LMGDNPs promoted NPCs autophagy by activating transforming growth factor β2 overlapping transcript 1 (TGFB2-OT1), relying on the nanozyme. MSCs-loaded LMGDNPs largely preserved disc hydration and alleviated matrix degradation in vivo. Summarily, LMGDNPs promoted cell survival and matrix regeneration by providing a nutrient supply, exhausting lactate, and activating autophagy via TGFB2-OT1 and its downstream pathway and may serve as an ideal delivery system for exogenous stem cell therapy and endogenous repair.

Argatroban promotes recovery of spinal cord injury by inhibiting the PAR1/JAK2/STAT3 signaling pathway

Argatroban is a synthetic thrombin inhibitor approved by U.S. Food and Drug Administration for the treatment of thrombosis. However, whether it plays a role in the repair of spinal cord injury is unknown. In this study, we established a rat model of T10 moderate spinal cord injury using an NYU Impactor Moder III and performed intraperitoneal injection of argatroban for 3 consecutive days. Our results showed that argatroban effectively promoted neurological function recovery after spinal cord injury and decreased thrombin expression and activity in the local injured spinal cord. RNA sequencing transcriptomic analysis revealed that the differentially expressed genes in the argatroban-treated group were enriched in the JAK2/STAT3 pathway, which is involved in astrogliosis and glial scar formation. Western blotting and immunofluorescence results showed that argatroban downregulated the expression of the thrombin receptor PAR1 in the injured spinal cord and the JAK2/STAT3 signal pathway. Argatroban also inhibited the activation and proliferation of astrocytes and reduced glial scar formation in the spinal cord. Taken together, these findings suggest that argatroban may inhibit astrogliosis by inhibiting the thrombin-mediated PAR1/JAK2/STAT3 signal pathway, thereby promoting the recovery of neurological function after spinal cord injury.

Trends in prevalence of fractures among adults in the United States, 1999-2020: a population-based study

BACKGROUND

Population data that examines recent national trends in the prevalence of fractures are lacking in the United States (US).

MATERIALS AND METHODS

Analyses were based on 1999-2020 data from the National Health and Nutrition Examination Survey (NHANES). Primary outcomes included the prevalence of hip, wrist, and vertebral fractures among adults aged greater than or equal to 50 years. Changes in the prevalence over time were determined by joinpoint regression analysis. The authors also described the variation by fracture subtypes, sociodemographic characteristics, and their combination.

RESULTS

For adults aged greater than or equal to 50 years in NHANES 2017-March 2020, the authors estimated that there was 2.6 million Americans with hip fractures, 14.6 million Americans with wrist fractures, and 5.2 million Americans with vertebral fractures. The prevalence of wrist fractures significantly increased from 8.7% (7.4-9.9%) in 1999-2000 to 12.8% (11.6-14.1%) in 2017-March 2020 among adults aged greater than or equal to 50 years ( P for trend=0.04); significant increases were also observed in fractures that occurred at age less than 50 years, non-Hispanic White, high family income groups, and several combination subgroups (e.g. fractures occurred at age <50 years among women). The prevalence of vertebral fractures increased from 2.2% (1.7-2.8%) in 1999-2000 to 4.6% (3.7-5.5%) in 2017-March 2020 among adults aged greater than or equal to 50 years ( P for trend=0.02); significant increases were also observed in 50-64 years, women, non-Hispanic White, high family income groups and several combination subgroups (e.g. fractures that occurred at age <50 years among women). The authors did not observe significant trend changes in the prevalence of hip fractures among adults aged greater than or equal to 50 years between 1999 and 2020.

CONCLUSION

The estimated prevalence of wrist and vertebral fractures significantly increased among US adults aged greater than or equal to 50 years from 1999 to 2020, although hip fractures did not significantly change.

An Engineered Bionic Nanoparticle Sponge as a Cytokine Trap and Reactive Oxygen Species Scavenger to Relieve Disc Degeneration and Discogenic Pain

The progressive worsening of disc degeneration and related nonspecific back pain are prominent clinical issues that cause a tremendous economic burden. Activation of reactive oxygen species (ROS) related inflammation is a primary pathophysiologic change in degenerative disc lesions. This pathological state is associated with M1 macrophages, apoptosis of nucleus pulposus cells (NPC), and the ingrowth of pain-related sensory nerves. To address the pathological issues of disc degeneration and discogenic pain, we developed MnO2@TMNP, a nanomaterial that encapsulated MnO2 nanoparticles with a TrkA-overexpressed macrophage cell membrane (TMNP). Consequently, this engineered nanomaterial showed high efficiency in binding various inflammatory factors and nerve growth factors, which inhibited inflammation-induced NPC apoptosis, matrix degradation, and nerve ingrowth. Furthermore, the macrophage cell membrane provided specific targeting to macrophages for the delivery of MnO2 nanoparticles. MnO2 nanoparticles in macrophages effectively scavenged intracellular ROS and prevented M1 polarization. Supportively, we found that MnO2@TMNP prevented disc inflammation and promoted matrix regeneration, leading to downregulated disc degenerative grades in the rat injured disc model. Both mechanical and thermal hyperalgesia were alleviated by MnO2@TMNP, which was attributed to the reduced calcitonin gene-related peptide (CGRP) and substance P expression in the dorsal root ganglion and the downregulated Glial Fibrillary Acidic Protein (GFAP) and Fos Proto-Oncogene (c-FOS) signaling in the spinal cord. We confirmed that the MnO2@TMNP nanomaterial alleviated the inflammatory immune microenvironment of intervertebral discs and the progression of disc degeneration, resulting in relieved discogenic pain.

[Epidemiological characteristics of a local cluster epidemic caused by the BA.2 evolutionary branch of Omicron variant]

Descriptive epidemiological methods were used to analyze the epidemiological characteristics of the local cluster of COVID-19 in the logistic park of Yuhang District in Hangzhou in March 2022. The cluster epidemic was detected by a case who actively visited the fever clinic. The epidemic lasted for 8 days, and a total of 58 cases (53 workers, 2 students, 1 farmer, 1 teacher and 1 unemployed) were found, including 40 males and 18 females. The age was (33.29±12.22) years. There cases were mainly in Yuhang District (48 cases, 82.77%) and Shangcheng District (7 cases, 12.07%) of Hangzhou. The real-time regeneration number peaked at 2.31 on March 10th and decreased to 0.37 on March 15th. The sequencing result of the indicated case was 100% homologous with the sequence uploaded from South Korea on March 4th, 2022.

[Clinical characteristics of epileptic seizure in neurofibromatosis type 1 in 15 cases]

Objective: To summarize the clinical characteristics of epileptic seizure associated with neurofibromatosis type 1 (NF1). Methods: From January 2017 to July 2023 at Children's Hospital Capital Institute of Pediatrics, medical records of patients with both NF1 and epileptic seizure were reviewed in this case series study. The clinical characteristics, treatment and prognosis were analyzed retrospectively. Results: A total of 15 patients(12 boys and 3 girls) were collected. Café-au-lait macules were observed in all 15 patients. There were 6 patients with neurodevelopmental disorders and the main manifestations were intellectual disability or developmental delay. The age at the first epileptic seizure was 2.5 (1.2, 5.5) years. There were various seizure types, including generalized tonic-clonic seizures in 8 patients, focal motor seizures in 6 patients, epileptic spasm in 4 patients, tonic seizures in 1 patient, absence in 1 patient, generalized myoclonic seizure in 1 patient and focal to bilateral tonic-clonic seizure in 1 patient. Among 14 patients whose brain magnetic resonance imaging results were available, there were abnormal signals in corpus callosum, basal ganglia, thalamus or cerebellum in 6 patients, dilated ventricles of different degrees in 3 patients, blurred gray and white matter boundary in 2 patients, agenesis of corpus callosum in 1 patient and no obvious abnormalities in the other patients. Among 13 epilepsy patients, 8 were seizure-free with 1 or 2 antiseizure medications(ASM), 1 with drug resistant epilepsy was seizure-free after left temporal lobectomy, and the other 4 patients who have received 2 to 9 ASM had persistent seizures. One patient with complex febrile convulsion achieved seizure freedom after oral administration of diazepam on demand. One patient had only 1 unprovoked epileptic seizure and did not have another seizure without taking any ASM. Conclusions: The first epileptic seizure in NF1 patients usually occurs in infancy and early childhood, with the main seizure type of generalized tonic-clonic seizure and focal motor seizure. Some patients have intellectual disability or developmental delay. Most epilepsy patients achieve seizure freedom with ASM.

A critical appraisal of clinical practice guidelines on surgical treatments for spinal cord injury

BACKGROUND CONTEXT

Spinal cord injury (SCI) is a global health problem with a heavy economic burden. Surgery is considered as the cornerstone of SCI treatment. Although various organizations have formulated different guidelines on surgical treatment for SCI, the methodological quality of these guidelines has still not been critically appraised.

PURPOSE

We aim to systematically review and appraise the current guidelines on surgical treatments of SCI and summarize the related recommendations with the quality evaluation of supporting evidence.

STUDY DESIGN

Systematic review.

METHODS

Medline, Cochrane library, Web of Science, Embase, Google Scholar, and online guideline databases were searched from January 2000 to January 2022. The most updated and recent guidelines containing evidence-based or consensus-based recommendations and established by authoritative associations were included. The Appraisal of Guidelines for Research and Evaluation, 2nd edition instrument containing 6 domains (eg, applicability) was used to appraise the included guidelines. An evidence-grading scale (ie, level of evidence, LOE) was utilized to evaluate the quality of supporting evidence. The supporting evidence was categorized as A (the best quality), B, C, and D (the worst quality).

RESULTS

Ten guidelines from 2008 to 2020 were included, however, all of them acquired the lowest scores in the domain of applicability among all the six domains. Fourteen recommendations (eight evidence-based recommendations and six consensus-based recommendations) were totally involved. The SCI types of the population and timing of surgery were studied. Regarding the SCI types of the population, eight guidelines (8/10, 80%), two guidelines (2/10, 20%), and three guidelines (3/10, 30%) recommended surgical treatment for patients with SCI without further clarification of characteristics, incomplete SCI, and traumatic central cord syndrome (TCCS), respectively. Besides, one guideline (1/10, 10%) recommended against surgery for patients with SCI without radiographic abnormality. Regarding the timing of surgery, there were eight guidelines (8/10, 80%), two guidelines (2/10, 20%), and two guidelines (2/10, 20%) with recommendations for patients with SCI without further clarification of characteristics, incomplete SCI, and TCCS, respectively. For patients with SCI without further clarification of characteristics, all eight guidelines (8/8, 100%) recommended for early surgery and five guidelines (5/8, 62.5%) recommended for the specific timing, which ranged from within 8 hours to within 48 hours. For patients with incomplete SCI, two guidelines (2/2, 100%) recommended for early surgery, without specific time thresholds. For patients with TCCS, one guideline (1/2, 50%) recommended for surgery within 24 hours, and another guideline (1/2, 50%) simply recommended for early surgery. The LOE was B in eight recommendations, C in three recommendations, and D in three recommendations.

CONCLUSIONS

We remind the reader that even the highest quality guidelines often have significant flaws (eg, poor applicability), and some of the conclusions are based on consensus recommendations which is certainly less than ideal. With these caveats, we found most included guidelines (8/10, 80%) recommended early surgical treatment for patients after SCI, which was consistent between evidence-based recommendations and consensus-based recommendations. Regarding the specific timing of surgery, the recommended time threshold did vary, but it was usually within 8 to 48 hours, where the LOE was B to D.

A novel mouse model of central cord syndrome

Patients with potential spinal stenosis are susceptible to central cord syndrome induced by blunt trauma. Suitable animal models are helpful for studying the pathogenesis and treatment of such injuries. In this study, we established a mouse model of acute blunt traumatic spinal cord injury by compressing the C6 spinal cord with 5 and 10 g/mm² compression weights to simulate cervical central cord syndrome. Behavioral testing confirmed that this model exhibited the characteristics of central cord syndrome because motor function in the front paws was impaired, whereas basic motor and sensory functions of the lower extremities were retained. Hematoxylin-eosin staining showed that the diseased region of the spinal cord in this mouse model was restricted to the gray matter of the central cord, whereas the white matter was rarely affected. Magnetic resonance imaging showed a hypointense signal in the lesion after mild and severe injury. In addition, immunofluorescence staining showed that the degree of nerve tract injury in the spinal cord white matter was mild, and that there was a chronic inflammation reaction. These findings suggest that this mouse model of central cord syndrome can be used as a model for preclinical research, and that gray matter is most vulnerable to injury in central cord syndrome, leading to impaired motor function.

Traumatic spinal injury-related hospitalizations in the United States, 2016-2019: a retrospective study

BACKGROUND

Traumatic spinal injury (TSI) is associated with significant fatality and social burden; however, the epidemiology and treatment of patients with TSI in the US remain unclear.

MATERIALS AND METHODS

An adult population was selected from the National Inpatient Sample database from 2016 to 2019. TSI incidence was calculated and TSI-related hospitalizations were divided into operative and nonoperative groups according to the treatments received. TSIs were classified as fracture, dislocation, internal organ injury, nerve root injury, or sprain injuries based on their nature. The annual percentage change (APC) was calculated to identify trends. In-hospital deaths were utilized to evaluate the prognosis of different TSIs.

RESULTS

Overall, 95 047 adult patients were hospitalized with TSI in the US from 2016 to 2019, with an incidence rate of 48.4 per 100 000 persons in 2019 (95% CI: 46.2-50.6). The total incidence increased with an APC of 1.5% (95% CI: 0.1-3%) from 2016 to 2019. Operative TSI treatment was more common than nonoperative (32.8 vs. 3.8; 95% CI: 32.3-33.2 vs. 3.6-4%). The number of operations increased from 37 555 (95% CI: 34 674-40 436) to 40 460 (95% CI: 37 372-43 548); however, the operative rate only increased for internal organ injury (i.e. spinal cord injury [SCI])-related hospitalizations (APC, 3.6%; 95% CI: 2.8-4.4%). In-hospital mortality was highest among SCI-related hospitalizations, recorded at 3.9% (95% CI: 2.9-5%) and 28% (95% CI: 17.9-38.2%) in the operative and nonoperative groups, respectively.

CONCLUSIONS

The estimated incidence of TSI in US adults increased from 2016 to 2019. The number of operations increased; however, the proportion of operations performed on TSI-related hospitalizations did not significantly change. In 2019, SCI was the highest associated mortality TSI, regardless of operative or nonoperative treatment.

Crosstalk between m6A mRNAs and m6A circRNAs and the time-specific biogenesis of m6A circRNAs after OGD/R in primary neurons

Cerebral ischaemiareperfusion injury is an important pathological process in nervous system diseases during which neurons undergo oxygenglucose deprivation and reoxygenation (OGD/R) injury. No study has used epitranscriptomics to explore the characteristics and mechanism of injury. N6methyladenosine (m6A) is the most abundant epitranscriptomic RNA modification. However, little is known about m6A modifications in neurons, especially during OGD/R. m6A RNA immunoprecipitation sequencing (MeRIPseq) and RNA-sequencing data for normal and OGD/R-treated neurons were analysed by bioinformatics. MeRIP quantitative real-time polymerase chain reaction was used to determine the m6A modification levels on specific RNAs. We report the m6A modification profiles of the mRNA and circRNA transcriptomes of normal and OGD/R-treated neurons. Expression analysis revealed that the m6A levels did not affect m6A mRNA or m6A circRNA expression. We found crosstalk between m6A mRNAs and m6A circRNAs and identified three patterns of m6A circRNA production in neurons; thus, distinct OGD/R treatments induced the same genes to generate different m6A circRNAs. Additionally, m6A circRNA biogenesis during distinct OGD/R processes was found to be time specific. These results expand our understanding of m6A modifications in normal and OGD/R-treated neurons, providing a reference to explore epigenetic mechanisms and potential treatments for OGD/R-related diseases.

Schwann Cell-Derived Exosomes and Methylprednisolone Composite Patch for Spinal Cord Injury Repair

Spinal cord injury (SCI) can cause permanent loss of sensory and motor function, and there is no effective clinical treatment, to date. Due to the complex pathological process involved after injury, synergistic treatments are very urgently needed in clinical practice. We designed a nanofiber scaffold hyaluronic acid hydrogel patch to release both exosomes and methylprednisolone to the injured spinal cord in a non-invasive manner. This composite patch showed good biocompatibility in the stabilization of exosome morphology and toxicity to nerve cells. Meanwhile, the composite patch increased the proportion of M2-type macrophages and reduced neuronal apoptosis in an in vitro study. In vivo, the functional and electrophysiological performance of rats with SCI was significantly improved when the composite patch covered the surface of the hematoma. The composite patch inhibited the inflammatory response through macrophage polarization from M1 type to M2 type and increased the survival of neurons by inhibition neuronal of apoptosis after SCI. The therapeutic effects of this composite patch can be attributed to TLR4/NF-κB, MAPK, and Akt/mTOR pathways. Thus, the composite patch provides a medicine-exosomes dual-release system and may provide a non-invasive method for clinical treatment for individuals with SCI.

Global, regional and national burden of traumatic brain injury and spinal cord injury, 1990-2019: a systematic analysis for the Global Burden of Disease Study 2019

OBJECTIVES

To evaluate the most up-to-date burden of traumatic brain injury (TBI) and spinal cord injury (SCI) and analyse their leading causes in different countries/territories.

DESIGN

An analysis of Global Burden of Disease (GBD) data.

SETTING

The epidemiological data were gathered from GBD Results Tool (1 January, 1990─31 December 2019) covering 21 GBD regions and 204 countries/ territories.

PARTICIPANTS

Patients with TBI/SCI.

MAIN OUTCOMES AND MEASURES

Absolute numbers and age-standardised rates/estimates of incidence, prevalence and years lived with disability (YLDs) of TBI/SCI by location in 2019, with their percentage changes from 1990 to 2019. The leading causes (eg, falls) of TBI/SCI in 204 countries/territories.

RESULTS

Globally, in 2019, TBI had 27.16 million new cases, 48.99 million prevalent cases and 7.08 million YLDs. SCI had 0.91 million new cases, 20.64 million prevalent cases and 6.20 million YLDs. Global age-standardised incidence rates of TBI decreased significantly by -5.5% (95% uncertainty interval -8.9% to -3.0%) from 1990 to 2019, whereas SCI had no significant change (-6.1% (-17.3% to 1.5%)). Regionally, in 2019, Eastern Europe and High-income North America had the highest burden of TBI and SCI, respectively. Nationally, in 2019, Slovenia and Afghanistan had the highest age-standardised incidence rates of TBI and SCI, respectively. For TBI, falls were the leading cause in 74% (150/204) of countries/territories, followed by pedestrian road injuries (14%, 29/204), motor vehicle road injuries (5%, 11/204), and conflict and terrorism (2%, 4/204). For SCI, falls were the leading cause in 97% (198/204) of countries/territories, followed by conflict and terrorism (3%, 6/204).

CONCLUSIONS

Global age-standardised incidence rates of TBI have decreased significantly since 1990, whereas SCI had no significant change. The leading causes of TBI/SCI globally were falls, but variations did exist between countries/territories. Policy-makers should continue to prioritise interventions to reduce falls, but priorities may vary between countries/territories.

Mendelian Randomization Study of Lipid Metabolites Reveals Causal Associations with Heel Bone Mineral Density

BACKGROUND

Osteoporosis, which is a bone disease, is characterized by low bone mineral density and an increased risk of fractures. The heel bone mineral density is often used as a representative measure of overall bone mineral density. Lipid metabolism, which includes processes such as fatty acid metabolism, glycerol metabolism, inositol metabolism, bile acid metabolism, carnitine metabolism, ketone body metabolism, sterol and steroid metabolism, etc., may have an impact on changes in bone mineral density. While some studies have reported correlations between lipid metabolism and heel bone mineral density, the overall causal relationship between metabolites and heel bone mineral density remains unclear.

OBJECTIVE

to investigate the causal relationship between lipid metabolites and heel bone mineral density using two-sample Mendelian randomization analysis.

METHODS

Summary-level data from large-scale genome-wide association studies were extracted to identify genetic variants linked to lipid metabolite levels. These genetic variants were subsequently employed as instrumental variables in Mendelian randomization analysis to estimate the causal effects of each lipid metabolite on heel bone mineral density. Furthermore, metabolites that could potentially be influenced by causal relationships with bone mineral density were extracted from the KEGG and WikiPathways databases. The causal associations between these downstream metabolites and heel bone mineral density were then examined. Lastly, a sensitivity analysis was conducted to evaluate the robustness of the results and address potential sources of bias.

RESULTS

A total of 130 lipid metabolites were analyzed, and it was found that acetylcarnitine, propionylcarnitine, hexadecanedioate, tetradecanedioate, myo-inositol, 1-arachidonoylglycerophosphorine, 1-linoleoylglycerophoethanolamine, and epiandrosterone sulfate had a causal relationship with heel bone mineral density (p < 0.05). Furthermore, our findings also indicate an absence of causal association between the downstream metabolites associated with the aforementioned metabolites identified in the KEGG and WikiPathways databases and heel bone mineral density.

CONCLUSION

This work supports the hypothesis that lipid metabolites have an impact on bone health through demonstrating a causal relationship between specific lipid metabolites and heel bone mineral density. This study has significant implications for the development of new strategies to osteoporosis prevention and treatment.

A spine segmentation method based on scene aware fusion network

BACKGROUND

Intervertebral disc herniation, degenerative lumbar spinal stenosis, and other lumbar spine diseases can occur across most age groups. MRI examination is the most commonly used detection method for lumbar spine lesions with its good soft tissue image resolution. However, the diagnosis accuracy is highly dependent on the experience of the diagnostician, leading to subjective errors caused by diagnosticians or differences in diagnostic criteria for multi-center studies in different hospitals, and inefficient diagnosis. These factors necessitate the standardized interpretation and automated classification of lumbar spine MRI to achieve objective consistency. In this research, a deep learning network based on SAFNet is proposed to solve the above challenges.

METHODS

In this research, low-level features, mid-level features, and high-level features of spine MRI are extracted. ASPP is used to process the high-level features. The multi-scale feature fusion method is used to increase the scene perception ability of the low-level features and mid-level features. The high-level features are further processed using global adaptive pooling and Sigmoid function to obtain new high-level features. The processed high-level features are then point-multiplied with the mid-level features and low-level features to obtain new high-level features. The new high-level features, low-level features, and mid-level features are all sampled to the same size and concatenated in the channel dimension to output the final result.

RESULTS

The DSC of SAFNet for segmenting 17 vertebral structures among 5 folds are 79.46 ± 4.63%, 78.82 ± 7.97%, 81.32 ± 3.45%, 80.56 ± 5.47%, and 80.83 ± 3.48%, with an average DSC of 80.32 ± 5.00%. The average DSC was 80.32 ± 5.00%. Compared to existing methods, our SAFNet provides better segmentation results and has important implications for the diagnosis of spinal and lumbar diseases.

CONCLUSIONS

This research proposes SAFNet, a highly accurate and robust spine segmentation deep learning network capable of providing effective anatomical segmentation for diagnostic purposes. The results demonstrate the effectiveness of the proposed method and its potential for improving radiological diagnosis accuracy.

Establishment of Central Cord Syndrome Model in C57BL/6J Mouse

Animal models of central cord syndrome (CCS) could substantially benefit preclinical research. Identifiable anatomical pathways can give minimally invasive exposure approaches and reduce extra injury to experimental animals during operation, enabling the maintenance of consistent and stable anatomical morphology during experiments to minimize behavioral and histological differences between individuals to improve the reproducibility of experiments. In this study, the C6 level spinal cord was exposed using a spinal cord injury coaxial platform (SCICP) and combination with a minimally invasive technique. With the assistance of a vertebral stabilizator, we fixed the vertebrae and compressed the spinal cords of C57BL/6J mice with 5 g/mm2 and 10 g/mm2 weights with SCICP to induce different degrees of C6 spinal cord injury. In line with the previous description of CCS, the results reveal that the lesion in this model is concentrated in the gray matter around the central cord, enabling further research into CCS. Finally, histological results are provided as a reference for the readers.

Sex-related Differences in Epidemiology, Treatment, and Economic Burden of Traumatic Spinal Cord Injury in China (2013-2018)

STUDY DESIGN

Retrospective epidemiological study.

OBJECTIVE

To describe differences based on biological sex in the epidemiology and treatment of the economic burden of traumatic spinal cord injury (TSCI) in China (2013-2018).

SUMMARY OF BACKGROUND DATA

Although there have been many regional single-center studies on TSCI in China, there are few reports involving multicenter data, especially those that report on discrepancies related to biological sex.

MATERIALS AND METHODS

This study is a nationally representative hospital-based retrospective study. The treatment data of TSCI patients in 30 hospitals in 11 provinces/cities from January 2013 to December 2018 were analyzed. Sociodemographic characteristics, accident and related injury characteristics, treatment methods, and hospital costs were obtained. Regression models were used to evaluate differences in the outcomes of interest based on biological sex and other factors.

RESULTS

There were 13,465 individuals with TSCI, with a mean age of 50.0 years, and females (52.2) older than males (49.3). Overall, the average ratio of males to females was 3.1:1, ranging from 3.0:1 in 2013 to 2.8:1 in 2018. The overall proportion of patients with TSCI increased from 2013 to 2018 [annual percentage change (APC)=6.8%, 95% CI, 3.3-10.4] ( P < 0.05). The percent increase in females (APC=8.2%, 95% CI, 5.6-10.8) was greater than that of males (APC=6.3%, 95% CI, 2.1-10.6). Overall, high-level falls mainly affected males (30.8%), and low-level falls mainly occurred in females (36.6%). Females demonstrated a higher frequency of thoracolumbar trauma and less severe neurological impairment.

CONCLUSIONS

This study suggests that although the main population of TSCI is male, the average ratio of males to females is decreasing. The frequency of TSCI may be increasing faster in females than in males. Therefore, it is necessary to develop sex-specific public prevention measures. In addition, more medical resources should be devoted to improving the ability of hospitals to perform early surgery.

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

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

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.

Targeting ANXA7/LAMP5-mTOR axis attenuates spinal cord injury by inhibiting neuronal apoptosis via enhancing autophagy in mice

Spinal cord injury (SCI) could lead to severe disabilities in motor and sensory functions, and cause a heavy burden on patient physiology and psychology due to lack of specific repair measures so far. ANXA7 is an annexin with Ca2+ -dependent GTPase activity, which were mainly expressed in neuron in spinal cord and downregulated significantly after SCI in mice. In our study, GTPase activity activation of ANXA7 plays the protective role in neuron after OGD/R through inhibiting neuron apoptosis, which mediated by enhancing autophagy via mTOR/TFEB pathway. We also discovered that ANXA7 has significant interaction with neural-specific lysosomal-associated membrane protein LAMP5, which together with ANXA7 regulates autophagy and apoptosis. Asp411 mutation of ANXA7 obviously impaired the interaction of ANXA7 and LAMP5 compared with the wild type. Furthermore, it was found that activation of ANXA7 could help to stabilize the protein expression of LAMP5. Overexpression of LAMP5 could attenuate the destruction of lysosomal acidic environment, inhibition of autophagy and activation of apoptosis caused by ANXA7 downregulation after OGD/R. We verified that injecting ANXA7 overexpression lentivirus and activation of ANXA7 both have significant repair effects on SCI mice by using CatWalk assay and immunohistochemistry staining. In summary, our findings clarify the new role of ANXA7 and LAMP5 in SCI, provided a new specific target of neuronal repair and discovered new molecular mechanisms of ANXA7 to regulate autophagy and apoptosis. Targeting ANXA7 may be a prospective therapeutic strategy for SCI in future.

Discovery of therapeutic targets for spinal cord injury based on molecular mechanisms of axon regeneration after conditioning lesion

BACKGROUND

Preinjury of peripheral nerves triggers dorsal root ganglia (DRG) axon regeneration, a biological change that is more pronounced in young mice than in old mice, but the complex mechanism has not been clearly explained. Here, we aim to gain insight into the mechanisms of axon regeneration after conditioning lesion in different age groups of mice, thereby providing effective therapeutic targets for central nervous system (CNS) injury.

METHODS

The microarray GSE58982 and GSE96051 were downloaded and analyzed to identify differentially expressed genes (DEGs). The protein-protein interaction (PPI) network, the miRNA-TF-target gene network, and the drug-hub gene network of conditioning lesion were constructed. The L4 and L5 DRGs, which were previously axotomized by the sciatic nerve conditioning lesions, were harvested for qRT-PCR. Furthermore, histological and behavioral tests were performed to assess the therapeutic effects of the candidate drug telmisartan in spinal cord injury (SCI).

RESULTS

A total of 693 and 885 DEGs were screened in the old and young mice, respectively. Functional enrichment indicates that shared DEGs are involved in the inflammatory response, innate immune response, and ion transport. QRT-PCR results showed that in DRGs with preinjury of peripheral nerve, Timp1, P2ry6, Nckap1l, Csf1, Ccl9, Anxa1, and C3 were upregulated, while Agtr1a was downregulated. Based on the bioinformatics analysis of DRG after conditioning lesion, Agtr1a was selected as a potential therapeutic target for the SCI treatment. In vivo experiments showed that telmisartan promoted axonal regeneration after SCI by downregulating AGTR1 expression.

CONCLUSION

This study provides a comprehensive map of transcriptional changes that discriminate between young and old DRGs in response to injury. The hub genes and their related drugs that may affect the axonal regeneration program after conditioning lesion were identified. These findings revealed the speculative pathogenic mechanism involved in conditioning-dependent regenerative growth and may have translational significance for the development of CNS injury treatment in the future.

[A case of combined oxidative phosphorylation deficiency 32 caused by MRPS34 gene variation and literature review]

Objective: To investigate the clinical features and genetic features of combined oxidative phosphorylation deficiency 32 (COXPD32) caused by MRPS34 gene variation. Methods: The clinical data and genetic test of a child with COXPD32 hospitalized in the Department of Neurology, Children's Hospital, Capital Institute of Pediatrics in March 2021 were extracted and analyzed. A literature search was implemented using Wanfang, China biology medicine disc, China national knowledge infrastructure, ClinVar, human gene mutation database (HGMD) and Pubmed databases with the key words "MRPS34" "MRPS34 gene" and "combined oxidative phosphorylation deficiency 32" (up to February 2023). Clinical and genetic features of COXPD32 were summarized. Results: A boy aged 1 year and 9 months was admitted due to developmental delay. He showed mental and motor retardation, and was below the 3^rd percentile for height, weight, and head circumference of children of the same age and gender. He had poor eye contact, esotropia, flat nasal bridge, limbs hypotonia, holding instability and tremors. In addition, Grade Ⅲ/6 systolic murmur were heard at left sternal border. Arterial blood gases suggested that severe metabolic acidosis with lactic acidosis. Brain magnetic resonance imaging (MRI) showed multiple symmetrical abnormal signals in the bilateral thalamus, midbrain, pons and medulla oblongata. Echocardiography showed atrial septal defect. Genetic testing identified the patient as a compound heterozygous variation of MRPS34 gene, c.580C>T (p.Gln194Ter) and c.94C>T (p.Gln32Ter), with c.580C>T being the first report and a diagnosis of COXPD32. His parents carried a heterozygous variant, respectively. The child improved after treatment with energy support, acidosis correction, and "cocktail" therapy (vitaminB₁, vitaminB₂, vitaminB₆, vitaminC and coenzyme Q10). A total of 8 cases with COXPD32 were collected through 2 English literature reviews and this study. Among the 8 patients, 7 cases had onset during infancy and 1 was unknown, all had developmental delay or regression, 7 cases had feeding difficulty or dysphagia, followed by dystonia, lactic acidosis, ocular symptoms, microcephaly, constipation and dysmorphic facies(mild coarsening of facial features, small forehead, anterior hairline extending onto forehead,high and narrow palate, thick gums, short columella, and synophrys), 2 cases died of respiratory and circulatory failure, and 6 were still alive at the time of reporting, with an age range of 2 to 34 years. Blood and (or) cerebrospinal fluid lactate were elevated in all 8 patients. MRI in 7 cases manifested symmetrical abnormal signals in the brainstem, thalamus, and (or) basal ganglia. Urine organic acid test were all normal but 1 patient had alanine elevation. Five patients underwent respiratory chain enzyme activity testing, and all had varying degrees of enzyme activity reduction. Six variants were identified, 6 patients were homozygous variants, with c.322-10G>A was present in 4 patients from 2 families and 2 compound heterozygous variants. Conclusions: The clinical phenotype of COXPD32 is highly heterogenous and the severity of the disease varies from development delay, feeding difficulty, dystonia, high lactic acid, ocular symptoms and reduced mitochondrial respiratory chain enzyme activity in mild cases, which may survive into adulthood, to rapid death due to respiratory and circulatory failure in severe cases. COXPD32 needs to be considered in cases of unexplained acidosis, hyperlactatemia, feeding difficulties, development delay or regression, ocular symptoms, respiratory and circulatory failure, and symmetrical abnormal signals in the brainstem, thalamus, and (or) basal ganglia, and genetic testing can clarify the diagnosis.

N1-Methyladenosine modification of mRNA regulates neuronal gene expression and oxygen glucose deprivation/reoxygenation induction

N¹-Methyladenosine (m1A) is an abundant modification of transcripts, plays important roles in regulating mRNA structure and translation efficiency, and is dynamically regulated under stress. However, the characteristics and functions of mRNA m1A modification in primary neurons and oxygen glucose deprivation/reoxygenation (OGD/R) induced remain unclear. We first constructed a mouse cortical neuron OGD/R model and then used methylated RNA immunoprecipitation (MeRIP) and sequencing technology to demonstrate that m1A modification is abundant in neuron mRNAs and dynamically regulated during OGD/R induction. Our study suggests that Trmt10c, Alkbh3, and Ythdf3 may be m1A-regulating enzymes in neurons during OGD/R induction. The level and pattern of m1A modification change significantly during OGD/R induction, and differential methylation is closely associated with the nervous system. Our findings show that m1A peaks in cortical neurons aggregate at both the 5' and 3' untranslated regions. m1A modification can regulate gene expression, and peaks in different regions have different effects on gene expression. By analysing m1A-seq and RNA-seq data, we show a positive correlation between differentially methylated m1A peaks and gene expression. The correlation was verified by using qRT-PCR and MeRIP-RT-PCR. Moreover, we selected human tissue samples from Parkinson's disease (PD) and Alzheimer's disease (AD) patients from the Gene Expression Comprehensive (GEO) database to analyse the selected differentially expressed genes (DEGs) and differential methylation modification regulatory enzymes, respectively, and found similar differential expression results. We highlight the potential relationship between m1A modification and neuronal apoptosis following OGD/R induction. Furthermore, by mapping mouse cortical neurons and OGD/R-induced modification characteristics, we reveal the important role of m1A modification in OGD/R and gene expression regulation, providing new ideas for research on neurological damage.

Unsaturated bond recognition leads to biased signal in a fatty acid receptor

Individual free fatty acids (FAs) play important roles in metabolic homeostasis, many through engagement with more than 40G protein-coupled receptors. Searching for receptors to sense beneficial omega-3 FAs of fish oil enabled the identification of GPR120, which is involved in a spectrum of metabolic diseases. Here, we report six cryo-electron microscopy structures of GPR120 in complex with FA hormones or TUG891 and Gi or Giq trimers. Aromatic residues inside the GPR120 ligand pocket were responsible for recognizing different double-bond positions of these FAs and connect ligand recognition to distinct effector coupling. We also investigated synthetic ligand selectivity and the structural basis of missense single-nucleotide polymorphisms. We reveal how GPR120 differentiates rigid double bonds and flexible single bonds. The knowledge gleaned here may facilitate rational drug design targeting to GPR120.

The landscape of m1A modification and its posttranscriptional regulatory functions in primary neurons

Cerebral ischaemia‒reperfusion injury (IRI), during which neurons undergo oxygen-glucose deprivation/reoxygenation (OGD/R), is a notable pathological process in many neurological diseases. N1-methyladenosine (m¹A) is an RNA modification that can affect gene expression and RNA stability. The m¹A landscape and potential functions of m¹A modification in neurons remain poorly understood. We explored RNA (mRNA, lncRNA, and circRNA) m¹A modification in normal and OGD/R-treated mouse neurons and the effect of m¹A on diverse RNAs. We investigated the m¹A landscape in primary neurons, identified m¹A-modified RNAs, and found that OGD/R increased the number of m¹A RNAs. m¹A modification might also affect the regulatory mechanisms of noncoding RNAs, e.g., lncRNA-RNA binding proteins (RBPs) interactions and circRNA translation. We showed that m¹A modification mediates the circRNA/lncRNA‒miRNA-mRNA competing endogenous RNA (ceRNA) mechanism and that 3' untranslated region (3'UTR) modification of mRNAs can hinder miRNA-mRNA binding. Three modification patterns were identified, and genes with different patterns had intrinsic mechanisms with potential m¹A-regulatory specificity. Systematic analysis of the m¹A landscape in normal and OGD/R neurons lays a critical foundation for understanding RNA modification and provides new perspectives and a theoretical basis for treating and developing drugs for OGD/R pathology-related diseases.

A critical appraisal of clinical practice guidelines on pharmacological treatments for spinal cord injury

BACKGROUND CONTEXT

Spinal cord injury brings devastating consequences and huge economic burden. Different authoritative organizations have developed different guidelines for pharmacological treatments of spinal cord injury, but there is a lack of a critical appraisal of them.

PURPOSE

To systematically review and appraise guidelines regarding their recommendations for pharmacological treatments for spinal cord injury.

STUDY DESIGN

Systematic review.

METHODS

We searched Medline, Embase, Cochrane, and Web of Science from January 2000 to January 2022 as well as guideline-specific databases (eg, Congress of Neurological Surgeons) and Google Scholar. We included the most updated guideline containing evidence-based recommendations or consensus-based recommendations developed by specific authoritative organizations if multiple versions were available. We appraised guidelines through the Appraisal of Guidelines for Research and Evaluation, 2nd edition instrument consisting of six domains (eg, applicability). With supporting evidence, recommendations were classified as: for, against, neither for nor against. We utilized an evidence assessment system to categorize the quality of supporting evidence as poor, fair, or good.

RESULTS

Eight guidelines developed from 2008 to 2020 were included, but all of them scored lowest in the domain of applicability among all six domains. Twelve pharmacological agents (eg, methylprednisolone) were studied. For methylprednisolone, three guidelines (3/8=37.5%) recommended for (one evidence-based and two consensus-based), three (3/8=37.5%) recommended against (all evidence-based), and two (2/8=25%) recommended neither for nor against. For monosialotetrahexosylganglioside (GM-1), one guideline (1/4=25%) recommended for (consensus-based), one (1/4=25%) recommended against (evidence-based), and two (2/4=50%) recommended neither for nor against. For other agents (eg, minocycline), most guidelines (3/5=60%) recommended neither for nor against, one (1/5=20%) recommended against naloxone (evidence-based) and nimodipine (evidence-based), and one (1/5=20%) recommended for neural growth factor (consensus-based). The quality of most of the supporting evidence was poor, and the rest was fair.

CONCLUSIONS

There were inconsistencies among recommendations for methylprednisolone and GM-1. Evidence-based recommendations tended to recommend against, whereas consensus-based recommendations tended to recommend for.

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.

Ang-(1-7)/MasR axis promotes functional recovery after spinal cord injury by regulating microglia/macrophage polarization

BACKGROUND

Inflammatory response is an essential part of secondary injury after spinal cord injury (SCI). During this period, the injury may be exacerbated through the release of a large number of inflammatory factors and the polarization of infiltrating macrophages and microglia towards M1. Ang-(1-7), mainly generated by Ang II via angiotensin-converting enzyme 2 (ACE2), can specifically bind to the G protein-coupled receptor Mas (MasR) and plays an important role in regulating inflammation and alleviating oxidative stress.

METHODS

We aimed to investigate whether activating the Ang-(1-7)/MasR axis in rats after SCI can regulate local neuroinflammation to achieve functional recovery and obtain its potential mechanism. MasR expression of bone marrow-derived macrophages was determined by Western blot. Immunofluorescence, Western blot, Flow cytometry, and RT-qPCR were applied to evaluate the polarization of Ang-(1-7) on macrophages and the regulation of inflammatory cytokines. Previous evaluation of the spinal cord and bladder after SCI was conducted by hematoxylin-eosin staining, Basso, Beattie, and Bresnahan (BBB) score, inclined plate test, electrophysiology, and catwalk were used to evaluate the functional recovery of rats.

RESULTS

MasR expression increased in macrophages under inflammatory conditions and further elevated after Ang-(1-7) treatment. Both in vivo and in vitro results confirmed that Ang-(1-7) could regulate the expression of inflammatory cytokines by down-regulating proinflammatory cytokines and up-regulating anti-inflammatory cytokines, and bias the polarization direction of microglia/macrophages to M2 phenotypic. After SCI, Ang-(1-7) administration in situ led to better histological and functional recovery in rats, and this recovery at least partly involved the TLR4/NF-κB signaling pathway.

CONCLUSION

As shown in our data, activating Ang-(1-7)/MasR axis can effectively improve the inflammatory microenvironment after spinal cord injury, promote the polarization of microglia/macrophages towards the M2 phenotype, and finally support the recovery of motor function. Therefore, we suggest using Ang-(1-7) as a feasible treatment strategy for spinal cord injury to minimize the negative consequences of the inflammatory microenvironment after spinal cord injury.

Prediction of knee pain improvement over two years for knee osteoarthritis using a dynamic nomogram based on MRI-derived radiomics: a proof-of-concept study

OBJECTIVES

To develop and validate a nomogram to detect improved knee pain in osteoarthritis (OA) by integrating magnetic resonance imaging (MRI) radiomics signature of subchondral bone and clinical characteristics.

METHODS

Participants were selected from the Vitamin D Effects on Osteoarthritis (VIDEO) study. The primary outcome was 20% improvement of knee pain score over 2 years in participants administrated either vitamin D or placebo. Radiomics features of subchondral bone and clinical characteristics from 216 participants were extracted and analyzed. The participants were randomly split into the training and validation cohorts at a ratio of 8:2. Least absolute shrinkage and selection operator (LASSO) regression was used to select features and generate radiomics signatures. The optimal radiomics signature and clinical indicators were fitted into a nomogram using multivariable logistic regression model.

RESULTS

The nomogram showed favorable discrimination performance [AUC_training, 0.79 (95% CI: 0.72-0.79), AUC_validation, 0.83 (95% CI: 0.70-0.96)] as well as a good calibration. Additional contributing value of fusion radiomics signature to the nomogram was statistically significant (NRI, 0.23; IDI, 0.14, P < 0.001 in training cohort and NRI, 0.29; IDI, 0.18, P < 0.05 in validating cohort). Decision curve analysis confirmed the clinical usefulness of nomogram.

CONCLUSION

The radiomics-based nomogram comprising the MR radiomics signature and clinical variables achieves a favorable predictive efficacy and accuracy in differentiating improvement in knee pain among OA patients. This proof-of-concept study provides a promising way to predict clinically meaningful outcomes.

Schwann cell-derived exosomes containing MFG-E8 modify macrophage/microglial polarization for attenuating inflammation via the SOCS3/STAT3 pathway after spinal cord injury

Macrophage/microglia polarization acts as an important part in regulating inflammatory responses in spinal cord injury (SCI). However, the regulation of inflammation of Schwann cell-derived exosomes (SCDEs) for SCI repair is still unclear. Therefore, we intend to find out the effect of SCDEs on regulating the inflammation related to macrophage polarization during the recovery of SCI. Firstly, the thesis demonstrated that SCDEs could attenuate the LPS- inflammation in BMDMs by suppressing M1 polarization and stimulating M2 polarization. Similarly, SCDEs improved functional recovery of female Wistar rats of the SCI contusion model according to BBB (Basso, Beattie, and Bresnahan) score, electrophysiological assay, and the gait analysis system of CatWalk XT. Moreover, MFG-E8 was verified as the main component of SCDEs to improve the inflammatory response by proteomic sequencing and lentiviral transfection. Improvement of the inflammatory microenvironment also inhibited neuronal apoptosis. The knockout of MFG-E8 in SCs can reverse the anti-inflammatory effects of SCDEs treatment. The SOCS3/STAT3 signaling pathway was identified to participate in upregulating M2 polarization induced by MFG-E8. In conclusion, our findings will enrich the mechanism of SCDEs in repairing SCI and provide potential applications and new insights for the clinical translation of SCDEs treatment for SCI.