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Due to the limited self-repairing capacity after peripheral nerve injuries (PNI), artificial nerve conduits are widely applied to facilitate neural regeneration. Exogenous electrical stimulation (ES) that is carried out by the conductive conduit regulates the biological behavior of Schwann cells (SCs). Meanwhile, a longitudinal surface structure counts to guide axonal growth to accelerate the end-to-end connection. Currently, there are no conduits equipped with both electrical conduction and axon-guiding surface structure. Herein, a biodegradable, conductive poly(l-lactide-co-caprolactone)/graphene (PLCL/GN) composite conduit is designed. The conduit with 20.96 ± 1.26 MPa tensile strength has a micropatterned surface of 20 µm groove fabricated by microimprint technology and self-assembled polydopamine (PDA). In vitro evaluation shows that the conduits with ES effectively stimulate the directional cell migration, adhesion, and elongation, and enhance neuronal expression of SCs. The rat sciatic nerve crush model demonstrates that the conductive micropatterned conduit with ES promotes the growth of myelin sheath, faster nerve regeneration, and 20-fold functional recovery in vivo. These discoveries prove that the PLCL(G)/PDA/GN composite conduit is a promising tool for PNI treatment by providing the functional integration of physical guidance, biomimetic biological regulation, and bioelectrical stimulation, which inspires a novel therapeutic approach for nerve regeneration in the future.

Objective To investigate the relationship between hypoxia inducible factor-1α (HIF-1α) and the autophagic response in osteoarthritic chondrocytes (OA), under inflammatory insult as represented by in vitro OA model. Methods Human chondrocyte cell line C28/I2 was cultured in both normoxic and hypoxic conditions and treated with interleukin-1β (IL1β) to emulate OA inflammatory insult in vitro. Cellular HIF-1α expression was silenced using siRNA transfection and cellular autophagic (P62/LC3II) response and OA chondrocyte damage (COL2A1/MMP13) related proteins were examined using western blotting. Cellular mitophagic (BNIP3/PINK1/Parkin) and apoptotic (Caspase/Cleaved Caspase 3) were also evaluated to assess mitophagy-mediated cell death due to HIF-1α silencing. Results Chondrocyte basal autophagy levels were higher in a HIF-1α elevated environment and was more resistant to IL1β-induced inflammatory insult. Increase in autophagic proteins showed better chondrocyte repair, which resulted a lower level of reactive oxygen species production, and lesser damage to chondrocyte integrity. Silencing HIF-1α activates cellular PINK1/Parkin and BNIP3 mitophagic proteins, which leads to the activation of Caspase/Cleaved Caspase 3 apoptotic cascade. Conclusion Our results show that chondrocyte autophagy is dependent on HIF-1α expression, showing the importance of HIF-1α in hypoxic chondrocyte function in OA. Dysregulation of HIF-1α expression results in the activation of mitophagy-mediated apoptosis.

Low responsiveness to anti-programmed death-1/programmed death-ligand 1 (anti-PD-1/PD-L1) for solid tumors indicates the presence of other immunosuppressive pathways. Siglec15, a newly discovered immune checkpoint, has been reported to repress immune responses in the tumor microenvironment (TME) and regulate osteoclast differentiation. However, the role of Siglec15 in the treatment for bone metastasis remains unclear. Herein, Siglec15 shows significantly higher expression in lung adenocarcinoma spinal metastasis (LUAD-SM) than in para-cancerous spinal tissues and primary LUAD. Subsequently, a TME-responsive hollow MnO

Background: Osteosarcoma (OS) is a common malignant bone tumor of mesenchymal origin that mainly occurred in adolescent. Chemotherapy resistance is a major difficulty in the treatment of OS. The aim of the present study was to analyze the function of Livin in the drug resistance of osteosarcoma. Methods: A drug-resistant MG-63 (MG-63/R) cell strain was established in vitro by continuously exposing human osteosarcoma MG-63 cells to doxorubicin at gradually increasing concentrations and then determining the index of resistance to doxorubicin. Transfected MG-63/R cells proliferation, viability, migration and invasion were determined with Cell Counting Kit-8 (CCK-8), live/dead cell staining, wound healing and Transwell assays, respectively, and the distribution of the cell cycle phase and apoptosis were determined by flow cytometry. Transcription of Livin mRNA was determined by quantitative real-time polymerase chain reaction (qRT-PCR), and relative expression of Bax, Bcl-2, caspase-3, cleaved caspase-3, MMP2-and MMP-9 were determined by western blot and qRT-PCR. Results: The expression of Livin mRNA was knockdown after transfecting Livin shRNA into MG-63/R cells (p < 0.001). Silencing Livin expression could repress the viability, proliferation, invasion and migration, induce apoptosis and increase Bax, caspase-3, cleaved caspase-3 levels yet decrease Bcl-2. MMP-2 and MMP-9 levels in MG-63/R cells.Conclusion: Silencing Livin gene expression can enhance the chemotherapeutic sensitivity of drug-resistant MG-63 osteosarcoma cells to doxorubicin, induce apoptosis and inhibit viability, proliferation, migration and invasion ability in MG-63/R cells, suggesting that Livin may serve as a promising therapeutic target for the drug resistance of human osteosarcoma.

Injectable materials show their special merits in regeneration of damaged/degenerated bones in minimally-invasive approach. Injectable calcium phosphate bone cement (CPC) has attracted broad attention for its bioactivity, as compared to non-degradable polymethyl methacrylate cement. However, its brittleness, poor anti-washout property and uncontrollable biodegradability are the main challenges to limit its further clinical application mainly because of its stone-like dense structure and fragile inorganic-salt weakness. Herein, we developed a kind of injectable CPC bone cement with porous structure and improved robustness by incorporating poly(lactide-co-glycolic acid) (PLGA) nanofiber into CPC, with carboxymethyl cellulose (CMC) to offer good injectability as well as anti-wash-out capacity. Furthermore, the introduction of PLGA and CMC also enabled a formation of initial porous structure in the cements, where PLGA nanofiber endowed the cement with a dynamically controllable biodegradability which provided room for cell movement and bone ingrowth. Interestingly, the reinforced biodegradable cement afforded a sustainable provision of Ca

Objective: To study the effects of different structures (solid/hollow) and pore diameters (300/600 μm) on bone ingrowth. Methods: Porous titanium alloy scaffolds (3.2 * 10.5 mm) were printed using electron beam melting. The implants were divided into either Hollow or Solid Group. The upper half of each implant was printed with a pore diameter of 600 μm while the bottom half was printed with a pore diameter of 300 μm. Visualization of the structural morphology was done using Scanning Electron Microscope (SEM). Cell proliferation was evaluated with the cell counting kit-8 assay and live/dead staining assay. The different lateral femoral condyles of 15 New Zealand rabbits were implanted with different groups of scaffolds. The rabbits were randomly sacrificed at the 4th, 8th, and 12th week postoperatively. Bone mineral density (BMD) and bone volume fraction (BV/TV) evaluation was completed by quantitative Micro-Computed Tomography (Micro-CT). Tissue histology were stained with toluidine blue to observe bone ingrowth under an optical microscope, and the percentage of new bone area were calculated using Image Pro-Plus 6.0. Results: SEM images showed a significant decrease in residual powder in the hollow implant and cell studies showed no obvious cytotoxicity for the Ti6Al4V scaffolds. Micro-CT reconstruction revealed high levels of new bone formation around the scaffolds. The trabeculae around the implants showed a gradual increase with each week, and new bone filled the scaffold pores gradually. BMD, BV/TV, and tissue histology revealed the 300 μm pore diameter is more conducive to bone ingrowth than the 600 μm ( p < .05). Conclusion: Our study revealed that Ti6Al4V implants with hollow structure could reduce the residual metal powder and implants with 300 μm pore diameter were more effective on bone formation than a 600 μm.

BACKGROUND: Non-small cell lung cancer (NSCLC) frequently metastasizes to bone, leading to poor prognosis. Siglec15 has been identified as a newly discovered immune checkpoint and exists in a variety of tumors. However, the expression and function of Siglec15 in NSCLC and bone metastasis remains largely unclear. METHODS: Siglec15 expression in NSCLC and the correlation between Siglec15 expression and the clinicopathological factors of patients with NSCLC were analyzed using The Cancer Genome Atlas (TCGA) dataset. Correlation analysis between Siglec15 and bone metastasis-related genes expression was based on the Molecular Signatures Database (MSigDB). Western blotting and immunohistochemistry were applied to detect Siglec15 expression in NSCLC and spinal metastasis. Human A549 and mouse CMT167 cells were transfected with Siglec15 siRNA to investigate its biological functions in NSCLC proliferation, migration, and invasion. The immune-related signaling pathways and correlations between Siglec15 and tumor-infiltrating immune cells and different immune checkpoints in the NSCLC tumor microenvironment (TME) were analyzed using Estimating Relative Subsets of RNA Transcripts (CIBERSORT) and gene set enrichment analysis (GSEA). To demonstrate Siglec15 in NSCLC cell-mediated T cell suppression and investigate the potential mechanism of Siglec15 silencing in antitumor immunity, we used a T cell killing assay in vitro and the high‑throughput sequencing approach. RESULTS: Siglec15 expression was positively associated with the tumor stage and lymph node metastasis, and was markedly up-regulated in NSCLC bone metastasis. Functionally, Siglec15 knockdown inhibited the proliferation, migration, and invasion of NSCLC cells (A549 and CMT167 cell lines). A total of eight kinds of tumor-infiltrating immune cells were found to have a strong association with the Siglec15 expression in NSCLC cases. The expression of previously discovered immune checkpoints was higher in the high Siglec15 expression NSCLC group. Furthermore, an in vitro T cell killing assay showed that the down-regulation of Siglec15 in tumor cells could enhance the antitumor immune responses of CD8(+) T cells. High‑throughput sequencing revealed the potential molecular mechanisms underlying the Siglec15-mediated immunosuppression effect of tumor cells on immune cells. CONCLUSIONS: Siglec15 may be involved in the pathogenesis of spinal metastasis in NSCLC and provide a new potential therapeutic target for the treatment of NSCLC and bone metastasis.

Background The epidemiology and cause of ossification of the spinal ligaments (OSL) remains obscure. To date, there is no study that comprehensively evaluates the prevalence, distribution, and concomitance of each type of OSL by CT among general Chinese population. We therefore aimed to comprehensively investigate epidemiological characteristics of OSL using whole spine CT in the Chinese population and examine the factors that correlate with the presence of OSL. Methods Ossification of the posterior longitudinal ligament (OPLL), ligamentum flavum (OLF), anterior longitudinal ligament (OALL), nuchal ligament (ONL), and diffuse idiopathic skeletal hyperostosis (DISH) were evaluated from the subjects who underwent PET/CT for the purpose of cancer screening in our hospital. Prevalence, distribution, and concomitance of OSL were reviewed. Logistic regression analysis was performed to identify the risk factors of OSL. Results A total of 2000 subjects (1335 men and 665 women) were included. The prevalence rate of cervical OPLL (C-OPLL) was 4.1%, thoracic OPLL (T-OPLL) 2.25%, lumbar OPLL (L-OPLL) 0.8%, thoracic OLF (T-OLF) 37.65%, lumbar OLF (L-OLF) 1.45%, ONL 31.5%, DISH 3.85%. The most commonly involved level was C5 for C-OPLL, T1 for T-OPLL, T10 for T-OLF, and T8/9 for OALL. 21% of subjects with C-OPLL had T-OPLL, 44% of C-OPLL had T-OLF, 38% of T-OPLL had C-OPLL, 53% of T-OPLL had T-OLF, 44% of L-OPLL had T-OPLL, and 56% of L-OPLL had T-OLF. The average age of OSL-positive subjects was significantly higher than that of OSL-negative subjects. The results of the multiple regression analysis revealed that males had a strong association with DISH (odds ratio, 3.15; 95% confidence interval, 1.27–7.78; P = 0.013). Conclusion The prevalence of OSL in the Chinese was revealed. Tandem ossification is not uncommon in people with OSL. There is a high incidence of multiple-regional OPLL in the whole spine. Approximately half of the subjects with OPLL coexist with T-OLF. For patients with clinical symptoms induced by OPLL, thorough evaluation of whole spine using CT is recommended.

This systematic review and meta-analysis of all available evidence was performed to assess the safety and efficacy of surgery for lumbar stenosis and spondylolisthesis in patients 80 years or older versus those younger than 80 years. A search of the literature was conducted in PubMed/MEDLINE, EMBASE and the Cochrane Collaboration Library. Relevant studies comparing the clinical outcomes of lumbar surgery in octogenarians and younger patients were selected according to the eligibility criteria. The predefined endpoints were extracted and meta-analysed from the identified studies. Data from 16 observational studies including 374,197 patients were included in the final analysis. The pooled data revealed that patients 80 years or older had a significantly higher incidence of overall complication, mortality, readmission and longer length of hospital stay than younger patients. There was a similar improvement in the clinical symptoms (Oswestry Disability Index and pain) of patients in the two groups. No significant differences in overall wound complication, reoperation rate, operative time and intraoperative blood loss were found between the groups. Our results revealed that the clinical improvement in pain and disability did not significantly differ according to age, although the patients aged 80 years or older had increased incidences of mortality and complication than younger patients. Age alone is not a contraindication for lumbar surgery in very old patients. A careful preoperative evaluation, proper patient selection and appropriate surgical approach are important to achieve successful surgical outcomes. These slides can be retrieved under Electronic Supplementary Material.

Recent studies have indicated that graphene and its derivative graphene oxide (GO) engage in a wide range of antibacterial activities with limited toxicity to human cells. Here, we systematically evaluate the dependence of GO toxicity on the size of the nanoparticles used in treatments: we compare the cytotoxic effects of graphene quantum dots (GQDs, μm). We synthesize the results of bacterial colony count assays and SEM-based observations of morphological changes to assess the antibacterial properties that these GOs bring into effect againstE. coli. We also use Live/Dead assays and morphological analysis to investigate changes to mammalian (Murine macrophage-like Raw 264.7) cells induced by the presence of the various GO particle types. Our results demonstrate that LGOs, SGOs, and GQDs possess antibacterial activities and cause mammalian cell cytotoxicity at descending levels of potency. Placing our observations in the context of previous simulation results, we suggest that both the lateral size and surface area of GO particles contribute to cytotoxic effects. We hope that the size dependence elucidated here provides a useful schematic for tuning GO-cell interactions in biomedical applications.