Intra-Inter Graph Representation Learning for Protein-Protein Binding Sites Prediction.

Graph neural networks have drawn increasing attention and achieved remarkable progress recently due to their potential applications for a large amount of irregular data. It is a natural way to represent protein as a graph. In this work, we focus on protein-protein binding sites prediction between the ligand and receptor proteins. Previous work just simply adopts graph convolution to learn residue representations of ligand and receptor proteins, then concatenates them and feeds the concatenated representation into a fully connected layer to make predictions, losing much of the information contained in complexes and failing to obtain an optimal prediction. In this paper, we present Intra-Inter Graph Representation Learning for protein-protein binding sites prediction (IIGRL). Specifically, for intra-graph learning, we maximize the mutual information between local node representation and global graph summary to encourage node representation to embody the global information of protein graph. Then we explore fusing two separate ligand and receptor graphs as a whole graph and learning affinities between their residues/nodes to propagate information to each other, which could effectively capture inter-protein information and further enhance the discrimination of residue pairs. Extensive experiments on multiple benchmarks demonstrate that the proposed IIGRL model outperforms state-of-the-art methods.

Consensus cluster analysis of apoptosis-related genes in patients with osteoarthritis and their correlation with immune cell infiltration.

Background: Osteoarthritis (OA) progression involves multiple factors, including cartilage erosion as the basic pathological mechanism of degeneration, and is closely related to chondrocyte apoptosis. To analyze the correlation between apoptosis and OA development, we selected apoptosis genes from the differentially expressed genes (DEGs) between OA and normal samples from the Gene Expression Omnibus (GEO) database, used lasso regression analysis to identify characteristic genes, and performed consensus cluster analysis to further explore the pathogenesis of this disease. Methods: The Gene expression profile datasets of OA samples, GSE12021 and GSE55235, were downloaded from GEO. The datasets were combined and analyzed for DEGs. Apoptosis-related genes (ARGs) were collected from the GeneCards database and intersected with DEGs for apoptosis-related DEGs (ARDEGs). Least absolute shrinkage and selection operator (LASSO) regression analysis was performed to obtain characteristic genes, and a nomogram was constructed based on these genes. A consensus cluster analysis was performed to divide the patients into clusters. The immune characteristics, functional enrichment, and immune infiltration statuses of the clusters were compared. In addition, a protein-protein interaction network of mRNA drugs, mRNA-transcription factors (TFs), and mRNA-miRNAs was constructed. Results: A total of 95 DEGs were identified, of which 47 were upregulated and 48 were downregulated, and 31 hub genes were selected as ARDEGs. LASSO regression analysis revealed nine characteristic genes: growth differentiation factor 15 (GDF15), NAMPT, TLR7, CXCL2, KLF2, REV3L, KLF9, THBD, and MTHFD2. Clusters A and B were identified, and neutrophil activation and neutrophil activation involved in the immune response were highly enriched in Cluster B, whereas protein repair and purine salvage signal pathways were enriched in Cluster A. The number of activated natural killer cells in Cluster B was significantly higher than that in Cluster A. GDF15 and KLF9 interacted with 193 and 32 TFs, respectively, and CXCL2 and REV3L interacted with 48 and 82 miRNAs, respectively. Conclusion: ARGs could predict the occurrence of OA and may be related to different degrees of OA progression.

Exosomes and osteosarcoma drug resistance.

Osteosarcoma (OS) is a primary malignant tumor of bone characterized by the formation of bone tissue or immature bone by tumor cells. Because of its multi-drug resistance, even with the improvement of chemotherapy and the use of targeted drugs, the survival rate of osteosarcoma (OS) is still less than 60%, and it is easy to metastasize, which is a difficulty for many clinicians and researchers. In recent years, with the continuous research on exosomes, it has been found that exosomes play a role in the diagnosis, treatment and chemotherapy resistance of osteosarcoma due to their unique properties. Exosomes can reduce the intracellular accumulation of chemotherapeutic drugs by mediating drug efflux, thus inducing chemotherapeutic resistance in OS cells. Exosomal goods (including miRNA and functional proteins) carried by exosomes also show great potential in affecting the drug resistance of OS. In addition, miRNA carried by exosomes and exosomes exist widely in tumor cells and can reflect the characteristics of parent cells, so it can also be used as a biomarker of OS. At the same time, the development of nanomedicine has given a new hope for the treatment of OS. Exosomes are regarded as good natural nano-carriers by researchers because of their excellent targeted transport capacity and low toxicity, which will play an important role in the field of OS therapy in the future. This paper reviews the internal relationship between exosomes and OS chemotherapy resistance, discusses the broad prospects of exosomes in the field of diagnosis and treatment of OS, and puts forward some suggestions for the study of the mechanism of OS chemotherapy resistance.

A finite element analysis on different bone cement forms and injection volumes injected into lumbar vertebral body in percutaneous kyphoplasty.

BACKGROUND: To investigate the stress changes between different bone cement forms and injection volumes in adjacent vertebrae after percutaneous kyphoplasty (PKP) by establishing a three-dimensional finite element model of osteoporosis. METHODS: A male healthy volunteer was selected. CT of scans L1 to L3 vertebrae were imported into Mimics 21.0 software.The vertebral model of osteoporosiswas established based on previous literature reference. The models were divided into three groups: unilateral, bilateral integration and bilateral separation groups, with each group injecting 2 ml, 4,ml and 6 ml of bone cement, respectively. In all models, a vertical compressive load of 500 N, anterior flexion/posterior extension, left/right bending, and left/right rotation were applied with a moment of 7.5 N/m, of which 85% was applied to the anterior mid-column and 15% to the posterior column. The stress changes between adjacent vertebrae under different conditions were calculated. RESULTS: After percutaneous kyphoplasty was applied to the L2 vertebral body, some differences can be found between the effects of different cement injection volumes and cement morphology on adjacent structures. There was no major difference between the groups when the bone cement injection volume was 2 ml. When the amount of bone cement injected was 4 ml, the bone cement morphology of the bilateral integration group (BIG) produced less stress between adjacent vertebral bodies. The minimum stress was 14.95 MPa in the L3 vertebral body in posterior extension. Whereas the stress levels on adjacent intervertebral structures, BIG shaped bone cement shows some superiority. In addition, the adjacent vertebrae and intervertebral structures are subjected to less stress during left and right rotation. CONCLUSIONS: The present finite element study suggested that bilateral integration bone cement is a suitable form of cement injection, and when the injection volume is 4 ml, reduces stress on adjacent segments by approximately 15% while maintaining the stability of the injected vertebral body.

Stromal cell-derived factor (SDF)-1α and platelet-rich plasma enhance bone regeneration and angiogenesis simultaneously in situ in rabbit calvaria.

The current study aimed to evaluate the effects of chemokine stromal cell-derived factor (SDF)-1α and platelet-rich plasma (PRP) on bone formation and angiogenesis, and to assess whether SDF-1α and PRP could function synergistically. Four evenly distributed defects (8 mm in diameter) were generated in the calvarial bones of New Zealand white rabbits. All rabbits received four treatment regimens containing autogenous bone particles (AB), SDF-1α, or PRP. AB group presented significantly less bone formation compared with the other three groups 2 and 4 weeks after surgery. The amount of newly formed bone in the AB+PRP+SDF-1α group was similar to that in the AB + SDF-1α group at the 4-week time-point (p = 0.65), and was much greater than that in the AB and AB+PRP group (p < 0.001). Meanwhile, more new blood vessels were formed in the AB+PRP, AB+SDF-1α, and AB+PRP+SDF-1α group versus the AB group. AB+PRP+SDF-1α group showed statistically increased angiogenesis compared with the AB+PRP and AB+SDF-1α groups (both p < 0.05) after treatment for 2 and 4 weeks. These findings indicated that SDF-1α and PRP might exhibit synergistic effects to promote angiogenesis in early bone regeneration.

Is laminoplasty or laminectomy the best strategy for C3 segment in French-door laminoplasty? A systematic review and meta-analysis.

BACKGROUND: To compare the clinical outcomes of C3 laminectomy and C3 laminoplasty at the C3 segment during French-door laminoplasty. METHODS: The Cochrane Library, PubMed, Embase, and Web of Science databases were searched from inception to November 10, 2020 for studies comparing the clinical outcomes of two types of French-door laminoplasty in the treatment of multilevel cervical spondylotic myelopathy (MCSM). Review Manager 5.3 was used to analyze the following outcomes: operative time, intraoperative blood loss, preoperative and postoperative Japanese Orthopaedic Association (JOA) scores, recovery rate, cervical curvature, cervical range of motion (ROM), incidence of axial symptoms (AS), and C2-3 bony fusion rate. RESULTS: A total of eight studies involving 776 patients were included; there were 424 patients in the C3 laminectomy group and 352 patients in the C3 laminoplasty group. The results of the meta-analysis showed that the C3 laminectomy group was superior to the C3 laminoplasty group in terms of operative time (P < 0.00001), cervical ROM (P = 0.04), and incidence of AS (P < 0.0001). However, no statistically significant differences between the two groups were noted regarding intraoperative bleeding (P = 0.44), preoperative JOA score (P = 0.57), postoperative JOA score (P = 0.09), recovery rate (P = 0.25), cervical curvature (P = 0.22), and C2-3 bony fusion rate (P = 0.06). CONCLUSION: This meta-analysis demonstrated that both C3 laminoplasty and C3 laminectomy could effectively improve neurological function in patients with MCSM in French-door laminoplasty. However, C3 laminectomy can reduce the operative time, preserve cervical ROM, and reduce the incidence of postoperative AS. TRIAL REGISTRATION: PROSPERO registration number is CRD42021230798 . Date of registration: February 11, 2021.

Open-Door versus French-Door Laminoplasty for Patients with Multisegmental Cervical Spondylotic Myelopathy: A Systematic Review and Meta-analysis.

This study aimed to evaluate the superiority of open-door versus French-door posterior cervical laminoplasty in the treatment of multisegmental cervical spondylotic myelopathy by comparing the intraoperative parameters and clinical and radiologic outcomes of these 2 procedures. PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure, the Wanfang database, the Weipu database, and China Biology Medicine disk were searched. Articles were retrieved from database establishment through May 22, 2020. Data analysis was carried out on the retrieved articles using RevMan 5.3 software. This meta-analysis included 14 studies involving 1010 patients, among which 6 were randomized controlled trials and 8 were retrospective analyses. Comparing the open-door and French-door groups, no statistically significant differences were found in operative time (weighted mean difference [WMD] = -4.47, 95% CI [-17.85, 8.92], P = 0.51), postoperative Japanese Orthopaedic Association score (WMD= -0.24, 95% CI [-0.87, 0.38], P = 0.45), recovery rate (WMD= -0.58, 95% CI [-3.61, 2.45], P = 0.71), postoperative cervical lordosis (WMD= -0.15, 95% CI [-1.93, 1.63], P = 0.87), cervical range of motion (WMD = -3.04, 95% CI [-8.68, 2.59], P = 0.29), sagittal diameter of the spinal canal (WMD = -0.24, 95% CI [-0.54, 0.07], P = 0.13), incidence of C5 palsy (OR = 1.78, 95% CI [0.64, 4.93], P = 0.27), or incidence of cerebrospinal fluid leakage (OR = 1.51, 95% CI [0.48, 4.71], P = 0.48). However, the French-door group was associated with less intraoperative bleeding (WMD = 54.96, 95% CI [21.37, 88.55], P = 0.001) and a lower incidence of axial symptoms (OR = 2.50, 95% CI [1.32, 4.72], P = 0.005). This analysis suggests that both methods can achieve good postoperative outcomes. However, less intraoperative bleeding and a lower incidence of postoperative axial symptoms were found in the French-door group. This requires further validation and investigation in larger sample-size and well-designed randomized controlled studies.

Combined Procedure Allowing Atlantoaxial and Atlanto-Occipital Joint Motion for Complex Injuries in the Upper Cervical Spine.

This study was performed to explore an ideal limited fixation method for the treatment of unstable atlantoaxial fractures that can preserve the range of motion of the occipital and atlantoaxial joints and restore the stability of the upper cervical spine. A 64-year-old man was diagnosed with a complicated injury of the upper cervical spine. The anterior and posterior approach was used to reconstruct the stability of the upper cervical spine while preserving the range of motion of the occipital and atlantoaxial joints. Preoperative imaging and neurologic examinations were performed. Follow-up lasted 24 months. The patient clinically improved after undergoing this novel procedure. Seven days postoperatively, the patient's visual analog scale score was 3. Follow-up contrast computed tomography showed good reduction and fixation in the upper cervical spine. Two weeks postoperatively, the patient displayed good cervical vertebral activity, with no restriction during flexion, extension, rotation, or other movements. No intraoperative or postoperative complications occurred. This modified procedure for restoration of cervical stability may be an improvement over traditional posterior fusion because atlantoaxial motion is preserved. [Orthopedics. 2020;43(4):e329-e333.].

Calcium-sensing receptor activating ERK1/2 and PI3K-Akt pathways to induce the proliferation of osteosarcoma cells.

Our results showed that the expression of calcium-sensing receptor (CaSR) and the concentration of intracellular calcium were enhanced in the osteosarcoma cells MG-63 compared with in the normal osteoblasts hFOB1.19. GdCl3 (CaSR agonist) significantly increased the proliferation rate of MG-63 cells, the expression of PCNA and Cyclin D1 and decreased the expression of p21Cip/WAF-1 . The effect of NPS2390 (CaSR antagonist) on the above indicators was opposite to GdCl3 . In addition, GdCl3 up-regulated the phosphorylation of ERK1/2, PI3K and Akt and the proliferation rate of MG-63 cells. However, these effects of GdCl3 were cancelled by LY294002 (a PI3K inhibitor) or PD98059 (an ERK1/2 inhibitor). Our results demonstrate that activation of CaSR promotes osteosarcoma cell multiplication by up-regulating ERK1/2 and PI3K-Akt pathways.

NFIL3 Acts as a Nuclear Factor to Increase Osteosarcoma Progression.

PURPOSE: Osteosarcoma is one of the most common primary malignant, aggressive bone neoplasms. However, the mechanisms of osteosarcoma proliferation, migration, and invasion are not well understood. To explore the possible mechanism of osteosarcoma progression, we used a public database for gene analysis to identify the possible factors that are important in osteosarcoma progression. Nuclear factor interleukin 3 (NFIL3) regulated was highly expressed in sarcoma tissues. In this study, we meant to probe the function of NFIL3 in osteosarcoma proliferation, migration, and invasion. METHODS: The expression of NFIL3 in osteosarcoma tissues was analysed via RT-PCR and immunohistochemistry staining. In order to elucidate the function of NFIL3 in osteosarcoma, we performed cell growth assays and colony formation assays to explore the role of NFIL3 in proliferation in osteosarcoma cells. Futhermore, we analysed osteosarcoma cell migration and invasion via wound healing assays and transwell migration and invasion assays. RESULTS: NFIL3 is overexpressed in osteosarcoma tissues; 15 of the 20 osteosarcoma tissues analysed highly expressed NFIL3. Our in vitro experiments confirmed that NFIL3 promoted the proliferation of M6-63 and SaOS2 cells (P < 0.01). In addition, NFIL3 promoted the migration and invasion of osteosarcoma cells (P < 0.05). CONCLUSION: NFIL3 is highly expressed in osteosarcoma tissues and thus promotes the proliferation, migration, and invasion of osteosarcoma cells. NFIL3 is potential to become a new target for development of novel treatment strategies of osteosarcoma.

Comparison of outcomes between cortical screws and traditional pedicle screws for lumbar interbody fusion: a systematic review and meta-analysis.

PURPOSE: The clinical outcomes of using a cortical screw (CS) for lumbar interbody fusion were evaluated by comparison with conventional pedicle screw (PS) fixation. METHODS: All of the comparative studies published in the PubMed, Cochrane Library, MEDLINE, Web of Science, and EMBASE databases recently as 18 March 2019, were included. All outcomes were analyzed by using Review Manager 5.3. RESULTS: Twelve studies were included with a total of 835 patients, and two of the studies were randomized controlled trials. The outcomes of the meta-analysis indicated that the use of CS fixation for lumbar interbody fusion was better than conventional PS fixation in regard to operating time (p = 0.02), intraoperative blood loss (p < 0.00001), length of stay (p = 0.02), incidence of complications (p = 0.02), adjacent segmental disease (ASD) incidence (p = 0.03), and Oswestry Disability Index (ODI) (p = 0.03). However, there were no statistically significant differences in the back and leg pain visual analog scale (VAS), Japanese Orthopaedic Association (JOA) scale, and intervertebral fusion rate (all p > 0.05) between the CS fixation group and the PS fixation group. CONCLUSIONS: Based on this systematic review and meta-analysis, our outcomes indicated that both CS and conventional PS can result in good postoperative outcomes in lumbar interbody fusion. No significant differences were found in the back and leg pain VAS, JOA scale, and intervertebral fusion rate. However, CS fixation is superior to PS fixation in the following measures: operating time, intraoperative blood loss, length of stay, incidence of complications, ASD incidence, and ODI. TRIAL REGISTRATION: PROSPERO registration number is CRD 42019132226 .

Hypoxia-induced resistance to cisplatin-mediated apoptosis in osteosarcoma cells is reversed by gambogic acid independently of HIF-1α.

In vitro evidence of hypoxia-induced resistance to cisplatin (CDDP)-mediated apoptosis exists in human osteosarcoma (OS). Gambogic acid (GA) is a promising chemotherapeutic compound that could increase the chemotherapeutic effectiveness of CDDP in human OS cells by inducing cell cycle arrest and promoting apoptosis. This study examined whether GA could overcome OS cell resistance to CDDP. Hypoxia significantly reduced levels of CDDP-induced apoptosis in the OS cell lines MG63 and HOS. However, combined treatment with GA and CDDP revealed a strong synergistic action between these drugs, and higher protein levels of the apoptosis-related factor Fas, cleaved caspase-8 and cleaved caspase-3 and lower expression of hypoxia-inducible factor (HIF)-1α are detected in both cell lines. Meanwhile, drug resistance was not reversed by exposure to the HIF-1α inhibitor 2-methoxyestradiol. These findings strongly suggest that hypoxia-induced resistance to CDDP is reversed by GA in OS cells independently of HIF-1α. Furthermore, in vivo studies using xenograft mouse models revealed that combination therapy with CDDP and GA exerted increased antitumor effects by inducing apoptosis. Taken together, our results demonstrate that GA may be a new potent therapeutic agent useful for targeting human OS cells.

Matrine inhibits the growth and induces apoptosis of osteosarcoma cells in vitro by inactivating the Akt pathway.

Matrine, a natural product, has been demonstrated to be a promising chemotherapeutic drug for some cancers. Using flow cytometric analysis of the cell cycle and apoptosis, we found that matrine inhibited the proliferation and induced apoptosis in the human osteosarcoma (OS) cell lines MG63, HOS, U2OS, and SAOS2 in vitro in a dose-dependent manner. We therefore assessed the role of the serine/threonine kinase Akt in the regulation of matrine-mediated cell growth inhibition and apoptosis induction in human OS cell lines. After treatment for 48 h, matrine induced G0/G1-stage cell cycle arrest in MG63, U2OS, and SAOS2 cells associated with an increase in the expression of p27(Kip1) and a decrease in the expression of Akt, glycogen synthase kinase 3 (GSK3)-ß (Ser9), and cyclin D1. Furthermore, the pro-apoptotic factor Bax was upregulated. Overall, our findings suggest that matrine may be an effective anti-osteosarcoma drug due to its ability to inhibit proliferation and induce apoptosis in OS cells, possibly through the involvement of Akt signaling.

Curcumin improves the recovery of motor function and reduces spinal cord edema in a rat acute spinal cord injury model by inhibiting the JAK/STAT signaling pathway.

Curcumin, a yellow pigment extracted from Carcuma longa, has been demonstrated to have extensive pharmacological activity in various studies, and it exhibits protective effects on injuries involving a number of human organs. The present study was designed to evaluate the potential effect and underlying mechanism of curcumin on the motor function and spinal cord edema in a rat acute spinal cord injury (SCI) model. The SCI model was induced by a heavy object falling. At 30min after the SCI was successfully induced, the animals were intraperitoneally given 40mg/kg curcumin. The Basso, Beattie and Bresnahan scores showed that curcumin moderately improved the recovery of the motor function in the injured rats, and hematoxylin-eosin staining demonstrated the role of this compound in reducing the hemorrhage, edema and neutrophil infiltration of the traumatic spinal cord. Furthermore, curcumin also inhibited the SCI-associated aquaporin - 4 (AQP4) overexpression and glial fibrillary acidic protein (GFAP) and repressed the unusual activation of the JAK/STAT signaling pathway. In conclusion, our data demonstrate that curcumin exhibits a moderately protective effect on spinal cord injury, and this effect might be related to the inhibition of overexpressed AQP4 and GFAP and the activated JAK/STAT signaling pathway. Curcumin may have potential for use as a therapeutic option for spinal cord injuries.

[Clinical application of a novel posterior lumbar fusion method and the short-term observation of its effect].

OBJECTIVE: To increase local blood supply of bone graft, a novel posterior lumbar spine fusion method with orthotopic paraspinal muscle-pediculated bone flaps was constructed, and the fusion rate and clinical effect.were observed. METHODS: From June 2007 to December 2010, 117 patients of lumbar spinal stenosis or lumbar destabilization treated with the novel posterior lumbar fusion method were studied, 49 males and 68 females, aged from 40 to 77 years, average 61.5 years. Clinical effect was evaluated by JOA and VAS score preoperatively and postoperatively, and the fusion result was evaluated by three-dimensional CT reconstruction postoperatively. RESULTS: Seventeen cases lost of follow up, the rest were followed up from 7 to 38 months, average 19 months. There was significant difference between pre- and postoperative JOA and VAS score (P < 0.01), the preoperative JOA score was 10.3 ± 1.9, and 25.4 ± 4.2 at the latest follow-up, the improvement rate was 81.0% ; the preoperative VAS score was 8.5 ± 0.8, and 2.3 ± 0.4 at the latest follow-up. The three-dimensional CT reconstruction showed that 126 of the 133 segments formed solid fusion in 100 patients who completed the follow-up, the fusion rate was 94.7%. CONCLUSION: The novel posterior lumbar fusion method make the bone graft position more precise, stable and increases the fusion rate, which can effectively reduce pseudarthrosis and have a promising clinical effect.

Inhibition of focal adhesion kinase induces apoptosis in human osteosarcoma SAOS-2 cells.

Focal adhesion kinase (FAK), a non-receptor tyrosine kinase protein, acts as an early modulator of integrin signaling cascade, regulating basic cellular functions. In transformed cells, unopposed FAK signaling has been considered to promote tumor growth, progression, and metastasis. The aim of this study was to assess the role of focal adhesion kinase in human osteosarcoma SAOS-2 cells. SAOS-2 cells were transfected with PGPU6/GFP/shNC, and PGPU6/GFP/FAK-334 (shRNA-334), respectively. Expression of FAK was detected by real-time PCR and western blots. MTT assay was used to examine changes in cell proliferation. Cell apoptosis was analyzed by flow cytometry. The expression of caspase-3,-7,-9 was measured by Western blots. The expression of FAK in SAOS-2 cells significantly decreased in shRNA-334 group contrast to the control group (P < 0.01). Cells proliferation was inhibited by shRNA-334 and shRNA-334 + cisplatin, and the effects were clearly enhanced when cells treated with the anticancer agents. The level of cell apoptosis in shRNA-334 and shRNA-334 + cisplatin group was higher than in the control group (P < 0.01). The current data support evidence that down-regulation of FAK could induce SAOS-2 apoptosis through the caspase-dependent cell death pathway. Inhibition of the kinases may be important for therapies designed to enhance the apoptosis in osteosarcoma.

Aggrecan variable number of tandem repeat polymorphism and lumbar disc degeneration: a meta-analysis.

STUDY DESIGN: Data on the association between the ACAN (encoded for aggrecan core protein) variable number of tandem repeat (VNTR) polymorphism and lumbar disc degeneration are conflicting, so we performed a meta-analysis. OBJECTIVE: Aggrecan is involved in the shock absorbing function of the lumbar disc; we performed a meta-analysis to assess the association between ACAN VNTR and lumbar degeneration. SUMMARY OF BACKGROUND DATA: To perform a meta-analysis, we searched for studies published until September 2012, using electronic databases (PubMed, EMBASE, and China National Knowledge Infrastructure). Eight studies involving 965 cases of lumbar disc degeneration and 982 control subjects were identified. METHODS: Assessment for eligibility and extraction of data were performed by 2 independent investigators. We extracted allele frequency for each study. We calculated the pooled odds ratios (ORs) and 95% confidence intervals (CI) to assess the strength of the association between the ACAN VNTR polymorphism and lumbar disc degeneration risk. RESULTS: Results from the allele model suggested an increased risk of lumbar disc degeneration for the shorter alleles carriers compared with the normal alleles and longer alleles (OR = 1.54, 95% CI: 1.04-2.30, P = 0.03). In subgroup analysis by ethnicity, significant increased risks were found among Asians with shorter alleles (OR=1.65, 95% CI: 1.17-2.33, P = 0.004). CONCLUSION: Our results suggest an increased risk of shorter alleles compared with normal alleles and longer alleles against lumbar disc degeneration among populations especially among Asian descent. Such association may not be statistically significant in European populations.

Tumor necrosis factor-α-dependent infiltration of macrophages into the dorsal root ganglion in a rat disc herniation model.

STUDY DESIGN: A prospective molecular mechanism of macrophages infiltration in experimental disc herniation. OBJECTIVE: To investigate the mechanisms of macrophages infiltration into the dorsal root ganglion (DRG) in a rat model of disc herniation. SUMMARY OF BACKGROUND DATA: Macrophages infiltrate the DRG after application of nucleus pulposus (NP) on the DRG, and may play an important role in radiculopathy. However, the mechanisms of macrophages infiltration after NP application remain poorly understood. METHODS: After experimental disc herniation in this study, we investigated changes in the expression of ED1 (a marker of macrophages) and vascular cell adhesion molecule-1 (VCAM-1) in DRG using immunofluorescence. We also investigated the expression of ED1 and VCAM-1 in DRG by treatment with tumor necrosis factor-α (TNF-α) inhibitor at the time of surgery. RESULTS: We found a massive ED1-positive macrophages infiltrated the DRG, and VCAM-1-like immunoreactivity vessels became evident after NP application. Furthermore, both macrophage infiltration and VCAM-1 expression were prevented by treatment with TNF-α inhibitor at the time of surgery. CONCLUSION: These findings indicated that macrophages infiltration into the DRG was TNF-α-dependent, and might be partly mediated by VCAM-1 in the early stage of experimental lumbar disc herination. Taken together, this study provides important preliminary data suggesting that TNF-α plays an important role in the macrophage infiltration. LEVEL OF EVIDENCE: N/A.

Viability inhibition effect of gambogic acid combined with cisplatin on osteosarcoma cells via mitochondria-independent apoptotic pathway.

We previously demonstrated that gambogic acid (GA) is a promising chemotherapeutic compound for human osteosarcoma treatment. The aim of this study was to detect whether the combination of lower-dose GA (0.3 mg/L) and cisplatin (CDDP) (1 mg/L) could perform a synergistic effect on inhibiting tumor in four osteosarcoma cell lines. Our results showed that the combination between GA at lower dose and CDDP significantly exerts a synergistic effect on inhibiting the cellular viability in MG63, HOS, and U2OS cells. In contrast, an antagonistic character was detected in SAOS2 cells exposed to the combined use of lower-dose GA (0.3 mg/L) and CDDP (1 mg/L). Then, analysis of cell cycle showed the combination of both drugs significantly induced the G2/M phase arrest, without any difference relative to GA treatment alone, in MG63 cells. Flow-cytometric analysis of cell apoptosis displayed that the apoptotic rate in the combination group is higher than that in GA treatment alone in MG63, HOS, and U2OS cells. The combined use of both drugs had no effect on mitochondrial membrane potential, but promoted the apoptosis-inducing function through triggering of CDDP in the three cell lines. By measurement of mitochondrial membrane potential, the activity of caspase-3 and the expressions of caspase-8 and caspase-9, it was showed that the apoptosis-promoting effect of the combined use of both drugs could be dependent on the death receptor apoptosis pathway, not dependent on the mitochondria apoptosis mechanism. This research, for the first time, demonstrates that GA could increase the chemotherapeutic effect of CDDP in human osteosarcoma treatment through inducing the cell cycle arrest and promoting cell apoptosis.

SDF-1 promotes endochondral bone repair during fracture healing at the traumatic brain injury condition.

PURPOSES: The objective of this study was to investigate the role of stromal cell-derived factor-1 (SDF-1) and its receptor, CXCR4, on bone healing and whether SDF-1 contributes to accelerating bone repair in traumatic brain injury (TBI)/fracture model. MATERIALS AND METHODS: Real-time polymerase chain reaction and immunohistochemical analysis were used to detect the expression of SDF-1 during the repair of femoral bone in TBI/fracture model. The TBI/fracture model was treated with anti-SDF-1 neutralizing antibody or AMD3100, an antagonist for CXCR4, and evaluated by histomorphometry. In vitro and in vivo migration assays were used to evaluate the functional effect of SDF-1 on primary mesenchymal stem cells. RESULTS: The expression of SDF1 and CXCR4 messenger RNA was increased during the bone healing in TBI/fracture model but was less increased in fracture only model. High expression of SDF-1 protein was observed in the surrounding tissue of the damaged bone. Treated with anti-SDF-1 antibody or AMD3100 could inhibit new bone formation. SDF-1 increased mesenchymal stem cell chemotaxis in vitro in a dose-dependent manner. The in vivo migration study demonstrated that mesenchymal stem cells recruited by SDF-1 participate in endochondral bone repair. CONCLUSION: The SDF-1/CXCR4 axis plays a crucial role in the accelerating fracture healing under the condition of TBI and contributes to endochondral bone repair.