Comparison of Direct Pars Repair Techniques for Spondylolysis in Young Patients: Pedicle Screw Hook System versus Pedicle Screw Rod.

Background: Lumbar spondylolysis (LS) poses a potential threat, and there is a need to evaluate and compare the effectiveness of direct pars repair techniques. Objective: To assess and compare the clinical and radiographic outcomes of direct pars repair techniques using the pedicle screw hook system (PSHS) and the pedicle screw rod system (PSRS) in young symptomatic patients with lumbar spondylolysis. Methods: A retrospective study was conducted to compare clinical and radiological data in young symptomatic LS patients after surgery. Records of 45 post-surgery LS patients with a minimum 24-month follow-up (January 2014 to June 2019) were reviewed. A total of 26 patients underwent PSHS, and 19 had PSRS. Treatment outcomes were analyzed using the visual analog pain scale (VAS), Oswestry disability index (ODI), MacNab criteria, lumbar fusion status, and Pfirrmann grading standards. Patient baseline characteristics were also compared between the two groups. Results: No disc degeneration was observed in either PSHS or PSRS groups at 24 months postoperatively, according to the Pfirrmann grading scale. The PSRS group outperformed the PSHS group in operative time, intraoperative blood loss, postoperative drainage, length of hospital stays, ODI, VAS values at 3 months postoperatively, and fusion status at 6 months postoperatively. No notable differences were observed in other parameters during the 24-month follow-up period, and no significant surgical complications were recorded. Conclusions: Direct pars repair techniques using PSHS and PSRS yielded satisfactory clinical and radiographic results in young patients with symptomatic LS. PSRS, compared to PSHS, demonstrated greater effectiveness in young individuals with LS and promoted early recovery.

M2 macrophage-derived exosomal miR-486-5p influences the differentiation potential of bone marrow mesenchymal stem cells and osteoporosis.

BACKGROUND: An imbalance between osteogenesis and adipogenesis in bone marrow mesenchymal stem cells (BMMSCs) can cause osteoporosis. Macrophage-derived exosomes (MD-Exos) and microRNAs (miRNAs) enriched in exosomes participate in the differentiation of BMMSCs. METHODS: Bioinformatics methods were used to analyze differentially expressed miRNAs. We cocultured M2 macrophages and BMMSCs to examine the biological function of exosomal microRNA-486-5p (miR-486-5p) on BMMSCs differentiation. Gain-of-function experiments related to osteogenesis were designed to investigate the effects of exosomes carrying miR-486-5p on an ovariectomized (OVX) mice model and the direct impact of miR-486-5p on BMMSCs. A dual luciferase experiment was performed to demonstrate the target gene of miR-486-5p. RESULTS: Bioinformatics analysis identified high expression of miRNA-486 in M2 macrophage-derived exosomes (M2D-Exos). The in vitro results demonstrated that M2 macrophage-derived exosomal miR-486-5p enhanced osteogenic capacity but inhibited the adipogenesis of BMMSCs. The direct effect of miR-486-5p on BMMSCs showed the same effects. Animal experiments revealed that exosomal miR-486-5p rescued bone loss of OVX mice. SMAD2 was characterized as a target gene of miR-486-5p. Pathway analysis showed that M2 macrophage-derived exosomal miR-486-5p stimulated osteogenic differentiation via the TGF-ß/SMAD2 signalling pathway. CONCLUSIONS: Taken together, M2 macrophage-derived exosomal miR-486-5p influences the differentiation potential of BMMSCs through the miR-486-5p/SMAD2/TGF-ß signalling pathway and osteoporosis.

Arginine methylation of PPP1CA by CARM1 regulates glucose metabolism and affects osteogenic differentiation and osteoclastic differentiation.

BACKGROUND: The imbalance between osteoblasts and osteoclasts may lead to osteoporosis. Osteoblasts and osteoclasts have different energy requirements, with aerobic glycolysis being the prominent metabolic feature of osteoblasts, while osteoclast differentiation and fusion are driven by oxidative phosphorylation. METHODS: By polymerase chain reaction as well as Western blotting, we assayed coactivator-associated arginine methyltransferase 1 (CARM1) expression in bone tissue, the mouse precranial osteoblast cell line MC3T3-E1 and the mouse monocyte macrophage leukaemia cell line RAW264.7, and expression of related genes during osteogenic differentiation and osteoclast differentiation. Using gene overexpression (lentivirus) and loss-of-function approach (CRISPR/Cas9-mediated knockout) in vitro, we examined whether CARM1 regulates osteogenic differentiation and osteoblast differentiation by metabolic regulation. Transcriptomic assays and metabolomic assays were used to find the mechanism of action of CARM1. Furthermore, in vitro methylation assays were applied to clarify the arginine methylation site of PPP1CA by CARM1. RESULTS: We discovered that CARM1 reprogrammed glucose metabolism in osteoblasts and osteoclasts from oxidative phosphorylation to aerobic glycolysis, thereby promoting osteogenic differentiation and inhibiting osteoclastic differentiation. In vivo experiments revealed that CARM1 significantly decreased bone loss in osteoporosis model mice. Mechanistically, CARM1 methylated R23 of PPP1CA, affected the dephosphorylation of AKT-T450 and AMPK-T172, and increased the activities of phosphofructokinase-1 and pructose-2,6-biphosphatase3, causing an up-regulation of glycolytic flux. At the same time, as a transcriptional coactivator, CARM1 regulated the expression of pyruvate dehydrogenase kinase 3, which resulted in the inhibition of pyruvate dehydrogenase activity and inhibition of the tricarboxylic acid cycle, leading to a subsequent decrease in the flux of oxidative phosphorylation. CONCLUSIONS: These findings reveal for the first time the mechanism by which CARM1 affects both osteogenesis and osteoclast differentiation through metabolic regulation, which may represent a new feasible treatment strategy for osteoporosis.

WTAP-Mediated m6A RNA Methylation Regulates the Differentiation of Bone Marrow Mesenchymal Stem Cells via the miR-29b-3p/HDAC4 Axis.

N6-methyladenosine (m6A) methylation, a well-known modification with new epigenetic functions, has been reported to participate in the progression of osteoporosis (OP), providing novel insights into the pathogenesis of OP. However, as the key component of m6A methylation, Wilms tumor 1-associated protein (WTAP) has not been studied in OP. Here we explored the biological role and underlying mechanism of WTAP in OP and the differentiation of bone marrow mesenchymal stem cells (BMMSCs). We demonstrated that WTAP was expressed at low levels in bone specimens from patients with OP and OVX mice. Functionally, WTAP promoted osteogenic differentiation and inhibited adipogenic differentiation of BMMSCs in vitro and in vivo. In addition, microRNA-29b-3p (miR-29b-3p) was identified as a downstream target of WTAP. M6A modifications regulated by WTAP led to increased miR-29b-3p expression. WTAP interacted with the microprocessor protein DGCR8 and accelerated the maturation of pri-miR-29b-3p in an m6A-dependent manner. Target prediction and dual-luciferase reporter assays identified the direct binding sites of miR-29b-3p with histone deacetylase 4 (HDAC4). WTAP-mediated m6A modification promoted osteogenic differentiation and inhibited adipogenic differentiation of BMMSCs through the miR-29b-3p/HDAC4 axis. Furthermore, WTAP-mediated m6A methylation negatively regulates osteoclast differentiation. Collectively, our study first identified a critical role of WTAP-mediated m6A methylation in BMMSC differentiation and highlighted WTAP as a potential therapeutic target for OP treatment.

VK2 Promotes Osteogenic Differentiation of BMSCs against High Glucose Exposure via Modulation of Intracellular Oxidative Stress.

INTRODUCTION: Diabetic osteoporosis (DOP) has gradually gained public attention. The clinical manifestations of DOP include bone mass loss, bone microstructural damage, and increased bone fragility.

WTAP-mediated m6A modification modulates bone marrow mesenchymal stem cells differentiation potential and osteoporosis.

An imbalance in the differentiation potential of bone marrow mesenchymal stem cells (BMSCs) is an important pathogenic mechanism underlying osteoporosis (OP). N6-methyladenosine (m6A) is the most common post-transcriptional modification in eukaryotic cells. The role of the Wilms' tumor 1-associated protein (WTAP), a member of the m6A functional protein family, in regulating BMSCs differentiation remains unknown. We used patient-derived and mouse model-derived samples, qRT-PCR, western blot assays, ALP activity assay, ALP, and Alizarin Red staining to determine the changes in mRNA and protein levels of genes and proteins associated with BMSCs differentiation. Histological analysis and micro-CT were used to evaluate developmental changes in the bone. The results determined that WTAP promoted osteogenic differentiation and inhibited adipogenic differentiation of BMSCs. We used co-immunoprecipitation (co-IP), RNA immunoprecipitation (RIP), methylated RNA immunoprecipitation (MeRIP), RNA pulldown, and dual-luciferase assay to explore the direct mechanism. Mechanistically, the expression of WTAP increased during osteogenic differentiation and significantly promoted pri-miR-181a and pri-miR-181c methylation, which was recognized by YTHDC1, and increased the maturation to miR-181a and miR-181c. MiR-181a and miR-181c inhibited the mRNA expression of SFRP1, promoting the osteogenic differentiation of BMSCs. Our results demonstrated that the WTAP/YTHDC1/miR-181a and miR-181c/SFRP1 axis regulated the differentiation fate of BMSCs, suggesting that it might be a potential therapeutic target for osteoporosis.

Ortho-silicic Acid Plays a Protective Role in Glucocorticoid-Induced Osteoporosis via the Akt/Bad Signal Pathway In Vitro and In Vivo.

Glucocorticoid-induced osteoporosis (GIOP) has been the most common form of secondary osteoporosis. Glucocorticoids (GCs) can induce osteocyte and osteoblast apoptosis. Plenty of research has verified that silicon intake would positively affect bone. However, the effects of silicon on GIOP are not investigated. In this study, we assessed the impact of ortho-silicic acid (OSA) on Dex-induced apoptosis of osteocytes by cell apoptosis assays. The apoptosis-related genes, cleaved-caspase-3, Bcl-2, and Bax, were detected by western blotting. Then, we evaluated the possible role of OSA on osteogenesis and osteoclastogenesis with Dex using Alizarin red staining and tartrate-resistant acid phosphatase (TRAP) staining. We also detected the related genes by quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and western blotting. We then established the GIOP mouse model to evaluate the potential role of OSA in vivo. We found that OSA showed no cytotoxic on osteocytes below 50 µM and prevented MLO-Y4 from Dex-induced apoptosis. We also found that OSA promoted osteogenesis and inhibited osteoclastogenesis with Dex. OSA had a protective effect on GIOP mice via the Akt signal pathway in vivo. In the end, we verified the Akt/Bad signal pathway in vitro, which showed the same results. Our finding demonstrated that OSA could protect osteocytes from apoptosis induced by GCs both in vitro and in vivo. Also, it promoted osteogenesis and inhibited osteoclastogenesis with the exitance of Dex. In conclusion, OSA has the potential value as a therapeutic agent for GIOP.

Combined Use of Tranexamic Acid and Rivaroxaban in Posterior/Transforaminal Lumbar Interbody Fusion Surgeries Safely Reduces Blood Loss and Incidence of Thrombosis: Evidence From a Prospective, Randomized, Double-Blind, Placebo-Controlled Study.

STUDY DESIGN: A prospective, randomized, double-blind, placebo-controlled study. OBJECTIVES: There are few studies examining the balance between preventing venous thrombus embolism (VTE) and reducing blood loss in posterior/transforaminal lumbar interbody fusion (PLIF/TLIF) surgeries. This study aimed to evaluate the efficacy and safety of the combine application of TXA and rivaroxaban in patients undergoing PLIF/TLIF and explore relevant factors related to blood loss and VTE. METHODS: Patients in group A which was the control group received 0.9% NaCl solution intravenously. Group B was treated by an intravenous injection of 2 g tranexamic acid (TXA) and the local use of 1 g intraoperatively. Group C was treated the same as group B intraoperatively, and they received 10 mg rivaroxaban qd treatment postoperatively. Eligible patients with an Autar score ≤ 10 were randomly assigned to group A or group B. Patients with an Autar score >10 were allocated into group C. RESULTS: The intraoperative blood loss and postoperative drainage were lower in groups B and C than in group A (P < .001). The blood transfusion rate in group B was lower than that in group A (P < .001), while the incidence of VTE in group C was lower (P < .001). Four factors were found to be positively correlated with obvious total blood loss (P < .05). The data showed that 5 factors were correlated with the development of a thrombus (P < .1). CONCLUSIONS: The combination of TXA and rivaroxaban in PLIF/TLIF patients is safe and effective in reducing D-dimer levels associated with VTE and reducing blood loss.

Association between single-nucleotide polymorphism rs145497186 related to NDUFV2 and lumbar disc degeneration: a pilot case-control study.

OBJECTIVE: The association between the single-nucleotide polymorphisms (SNPs) rs28742109, rs12955018, rs987850, rs8093805, rs12965084 and rs145497186 related to gene named NADH dehydrogenase [ubiquinone] flavoprotein 2 (NDUFV2) and lumbar disc degeneration (LDD) was preliminary investigated in a small sample size. METHODS: A total of 46 patients with LDD and 45 controls were recruited at Qilu Hospital of Shandong University, and each participant provided 5 mL peripheral venous blood. NA was extracted from the blood of each participant for further genotyping. The frequency of different genotypes in the case group and control group was determined, and analysis of the risk of LDD associated with different SNP genotypes was performed. The visual analogue scale (VAS) scores of the patients' degree of chronic low back pain were calculated, and the relationship between VAS scores and SNPs was analysed. RESULTS: After excluding the influence of sex, age, height, and weight on LDD, a significant association between SNP rs145497186 related to NDUFV2 and LDD persisted (P = 0.006). Simultaneously, rs145497186 was found to be associated with chronic low back pain in LDD populations. CONCLUSION: NDUFV2 rs145497186 SNP could be associated with susceptibility to LDD and the degree of chronic low back pain.

Exosomal MiR-199a-5p Inhibits Tumorigenesis and Angiogenesis by Targeting VEGFA in Osteosarcoma.

Background: Osteosarcoma (OS) is the most common primary bone malignancy in children and adolescents. microRNAs have been found to play a vital role in tumor angiogenesis. Here, we investigated the effects of miR-199a-5p on tumor growth and angiogenesis in osteosarcoma. Furthermore, the underlying molecular mechanisms and signaling pathways were explored. Methods: The datasets were extracted from the Gene Expression Omnibus and the differentially expressed miRNAs (DEmiRNAs) were screened out by the GEO2R online platform. The potential target genes were predicted using the miRTarBase database. The predicted target genes were further analyzed by Gene Ontology and pathway enrichment analysis and a regulatory network of DEmiRNAs and their target genes was constructed. In addition, the effects of osteosarcoma cell derived exosomal miR-199a-5p on the proliferation, migration and neovascularization of HUVECs were evaluated by conducting EdU assays, Transwell experiments and tube formation assays. A dual-luciferase reporter assay was performed to detect whether VEGFA was the direct target of miR-199a-5p. Furthermore, in vivo xenograft models were established to further investigate the intrinsic role of miR-199a-5p in osteosarcoma tumorigenesis and angiogenesis. Results: A total of 149 DE-miRNAs were screened out, including 136 upregulated miRNAs and 13 downregulated miRNAs in human osteosarcoma plasma samples compared with normal plasma samples. A total of 1313 target genes of the top three upregulated and downregulated miRNAs were predicted. In the PPI network, the top 10 hub nodes with higher degrees were identified as hub genes, such as TP53 and VEGFA. By constructing the miRNA-hub gene network, we found that most of hub genes could be potentially modulated by miR-663a, miR-199a-5p and miR-223-3p. In addition, we found that the expression level of miR-199a-5p in exosomes derived from osteosarcoma cells was remarkably higher than the osteosarcoma cells, and the exosomes derived from osteosarcoma cells were transported to HUVECs. Overexpression of miR-199a-5p could significantly inhibited HUVEC proliferation, migration and neovascularization, whereas downregulation of miR-199a-5p expression exerted the opposite effect. Moreover, the in vivo results verified that overexpression of miR-199a-5p in osteosarcoma cells could suppress the growth and angiogenesis of tumors. Conclusion: Our results demonstrated that miR-199a-5p could be transported from osteosarcoma cells to HUVECs through exosomes, subsequently targeting VEGFA and inhibiting the growth and angiogenesis of osteosarcoma. Therefore, miR-199a-5p may act as a biomarker in the diagnosis and treatment of osteosarcoma.

Relationship between Scheuermann disease and symptomatic thoracic spinal stenosis: A retrospective study.

OBJECTIVE: This study aimed to investigate the possible relationship between Scheuermann disease (SD) and the pathophysiological factors of thoracic spinal stenosis (TSS), including ossification of the ligamentum flavum (OLF), ossification of the posterior longitudinal ligament (OPLL), and thoracic disc herniation (TDH) in patients with symptomatic TSS. METHODS: Demographic and radiological data from 66 consecutive patients diagnosed with symptomatic TSS from 2013 to 2018 were retrospectively collected and divided into 3 groups depending on the underlying pathomechanism of TSS: TDH group (18 patients; 6 women; mean age ± standard deviation [Sd] = 59.89 ± 11.34), OPLL group (12 patients; 8 women; mean age ± Sd = 56.08 ± 14.74), and OLF group (36 patients; 20 women; mean age ± Sd = 58.69 ± 9.77). A total of 41 age-matched healthy individuals (19 women; mean age ± Sd = 54.88 ± 13.63) were designated as the control group. In each group, both typical and atypical SD criteria were radiologically examined. The demographic data and presence of SD between the control group and 3 subgroups of TSS pathomechanisms were evaluated. RESULTS: SD characteristics were identified in 83.33% (15/18) of patients in the TDH group, 44.44% (16/36) in the OLF group, 25% (3/12) in the OPLL group, and 17.07% (7/41) of the control individuals. When analyzed by the chi-squared test and logistic regression analysis, the presence of SD was significantly associated with TDH (P < 0.01) and OLF (P < 0.05) but not OPLL (P > 0.05). Patients with TDH and OLF showed peak involvement of T10/11, and patients with OPLL did not. Furthermore, we determined that age, sex, body-mass index, and smoking status were not the risk factors for TDH, OPLL, and OLF (P > 0.05). SD was found to be a risk factor for TDH (P < 0.01) and OLF (P < 0.05) but not for OPLL (P > 0.05). CONCLUSION: Evidence from this study indicated that SD might be a risk factor for OLF and TDH but not for OPLL.

Bionic Tiger-Bone Powder Improves Bone Microstructure and Bone Biomechanical Strength of Ovariectomized Rats.

OBJECTIVE: To study the curative effect of bionic tiger-bone powder on osteoporosis in ovariectomized rats and investigate its mechanism. METHODS: Overall, a 120 female Wistar rats were randomly divided into Sham (sham-operated group), ovariectomy (OVX, ovariectomized group), TB (bionic tiger-bone powder treatment group after ovariectomy) and TB + VD groups (bionic tiger-bone powder + vitamin D treatment group after ovariectomy). The osteoporotic rat model was established 3 months after ovariectomy, and rats were intragastrically administrated with the corresponding drugs. Serum and bone tissue samples were collected from 10 rats in each group at weeks 4, 12 and 24 after intragastric administration. The bone microstructure of L6 vertebrae was analyzed by MicroCT, the biomechanical strength of left femurs was measured by the three-point bending test, and serum bone metabolism markers (P1NP and CTX) were detected by ELISA. Changes in bone collagen were analyzed by Masson's trichrome staining and hydroxyproline detection, and members of the BMP2/SMAD/RUNX2 and OPG/RANKL/RANK signal pathways were detected by immunoblotting. RESULTS: Compared with the OVX group, the serum level of P1NP in the TB and TB + VD groups was higher (P < 0.05), while the CTX level was lower (P < 0.05). Bone collagen fiber structures in the TB and TB + VD groups were repaired, and the collagen content was significantly higher than that in the OVX group (P < 0.05). In the TB group, BMP-2, P-SMAD1/5, RUNX2 and OPG levels were increased in bone tissue (P < 0.01), RANKL levels were decreased (P < 0.01), and the bone microstructure and biomechanical strength were improved. CONCLUSION: Bionic tiger-bone powder promotes osteogenesis by activating the BMP2/SMAD/RUNX2 signaling pathway, suppresses osteoclasts by downregulating the OPG/RANK/RANKL signaling pathway, increases bone collagen content, and improves bone microstructure and bone biomechanical strength.

BMPR2 expression level is correlated with low immune infiltration and predicts metastasis and poor survival in osteosarcoma.

Osteosarcoma is the most common malignant bone tumor in adolescents and young adults, and identifying biomarkers for prognosis and therapy is necessary. Bone morphogenetic protein receptor 2 (BMPR2) is involved in various cellular functions, including cell adhesion, proliferation and invasion, inflammation, apoptosis and metastatic spread. However, the correlation between BMPR2 expression levels and prognosis and tumor-infiltrating immune cells in osteosarcoma is not well understood. In the present study, the expression level of BMPR2 was investigated using the Oncomine and R2 databases. The association between the expression level of BMPR2 and the clinical prognosis of patients with cancer was analyzed using the R2 database. The relationship between the expression level of BMPR2 and immune cell infiltration in the stroma of osteosarcoma was assessed using the Tumor Immune Estimation Resource (TIMER) and CIBERSORT. The correlations between BMPR2 expression level and infiltrated immune cell gene marker sets in osteosarcoma were validated in the TIMER and R2 databases. Analysis of a cohort of patients with osteosarcoma revealed that BMPR2 expression was significantly higher in osteosarcoma compared with in normal tissue and was correlated with poor prognosis. M0 macrophages, M2 macrophages, resting mast, γ δ T and CD8+ T cells were the top five immune cells with the highest degrees of infiltration in osteosarcoma. In addition, BMPR2 expression level showed a significant negative correlation with the gene markers of CD8+ T cells, monocytes and M2 macrophages. Low levels of infiltrating CD8+ T cells, monocytes or M2 macrophages in osteosarcoma was significantly associated with poor survival. These data suggested that CD8+ T cells, monocytes and M2 macrophages play significant roles in the establishment of the immune microenvironment of osteosarcoma. High BMPR2 expression was associated with poor prognosis and low infiltration of CD8+ T cells, monocytes and M2 macrophages in osteosarcoma. Hence, BMPR2 can be considered a biomarker of the immune infiltration, metastasis and prognosis of osteosarcoma.

Ortho-silicic acid enhances osteogenesis of osteoblasts through the upregulation of miR-130b which directly targets PTEN.

AIMS: Osteoporosis is considered a common skeletal disease. Ortho-silicic acid has been found to enhance the osteogenic differentiation of osteoblasts. However, the molecular mechanism of osteogenesis induced by ortho-silicic acid is still undefined totally. MicroRNAs (miRs) play a key role in osteogenesis of osteoblasts. This study investigated the role of miR-130b in promoting osteogenesis induced by ortho-silicic acid. MAIN METHODS AND KEY FINDINGS: In this study, we found ortho-silicic acid enhanced osteogenesis of osteoblasts in vitro and promoted preventing and treating osteoporosis in vivo. Furthermore, the expression of miR-130b increased under application of ortho-silicic acid. In vitro, experiments demonstrated miR-130b overexpression or inhibition significantly promoted or suppressed osteogenic differentiation of osteoblasts under application of ortho-silicic acid, respectively. Consistently, downregulation of miR-130b in ovariectomy (OVX) rats dropped off the beneficial effect of ortho-silicic acid against bone loss. Mechanistically, we identified phosphatase and tensin homologue deleted on human chromosome 10 (PTEN) as the direct target of miR-130b during osteogenesis induced by ortho-silicic acid. SIGNIFICANCE: In conclusion, our findings reveal that ortho-silicic acid promotes the osteogenesis of osteoblasts mediated by the miR-130b/PTEN signaling axis, which identifies a new target to prevent and treat osteoporosis.

Ortho-silicic Acid Inhibits RANKL-Induced Osteoclastogenesis and Reverses Ovariectomy-Induced Bone Loss In Vivo.

Numerous experiments in vitro and in vivo have shown that an appropriate increase intake of silicon can facilitate the synthesis of collagen and its stabilization and promote the differentiation and mineralization of osteoblasts. In this study, we examined whether ortho-silicic acid restrains the differentiation of osteoclast through the receptor activator of nuclear factor κB ligand (RANKL)/receptor activator of nuclear factor κB (RANK)/osteoprotegerin (OPG) signaling pathway by investigating its effect in vitro and in vivo. Bone marrow macrophage (BMM) cells were isolated and cultured with or without ortho-silicic acid, and then TRAP staining and immunofluorescence were performed to detect the differentiation of osteoclast. The RANKL-induced osteoclast marker gene and protein expression including c-Fos, nuclear factor of activated T cells cl (NFATcl), tumor necrosis factor receptor-associated factor 6 (TRAF6), nuclear factor kappa B P50 (NF-κB P50), NF-κB P52, RANK, integrin ß3, cathepsin K (CTSK), DC-STAMP, and TRAP were quantitatively detected by western blot and RT-PCR. Ovariectomized (OVX) rats were injected with ortho-silicic acid (OVX+Si group) and normal saline (OVX group), and sham-operated rats were injected with normal saline (Sham group). And micro-CT, H&E, and TRAP staining, ELISA, and western blot were performed. Ortho-silicic acid could inhibit the differentiation of osteoclast, and the marker genes and proteins were decreased. The OVX-induced bone loss could be reversed by ortho-silicic acid. Our finding demonstrated that ortho-silicic acid suppresses RANKL-induced osteoclastogenesis and has potential value as a therapeutic agent for OVX-induced bone loss.

Resveratrol Protects Osteoblasts Against Dexamethasone-Induced Cytotoxicity Through Activation of AMP-Activated Protein Kinase.

PURPOSE: Glucocorticoids are used for the treatment of inflammatory diseases, but glucocorticoid treatment is associated with bone damage. Resveratrol is a phytoalexin found in many plants, and we investigated its protective role on dexamethasone-induced dysfunction in MC3T3-E1 cells and primary osteoblasts. MATERIALS AND METHODS: MC3T3-E1 cells and primary osteoblasts were treated with dexamethasone in the presence/absence of different doses of resveratrol for 24 or 48 h. Then, 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium (MTT) and lactate dehydrogenase (LDH) assays were used to evaluate cell viability. Apoptosis was analyzed by a flow cytometry. An alkaline phosphatase (ALP) activity assay and Alizarin Red S staining were used to study osteoblast differentiation. Expression of osteoblast-related genes was measured by real-time reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The AMP-activated protein kinase (AMPK) signaling pathway and mitochondrial expression of superoxide dismutase were evaluated by Western blotting. Intracellular reactive oxygen species (ROS), adenosine triphosphate (ATP) content, mitochondrial-complex activity, and mitochondrial DNA content were measured to evaluate mitochondrial function. RESULTS: Resveratrol induced the proliferation and inhibited apoptosis of osteoblasts in the presence of dexamethasone. Resveratrol increased the ALP activity and mineralization of osteoblasts. Resveratrol also attenuated dexamethasone-induced inhibition of mRNA expression of osteogenesis maker genes, including bone morphogenetic protein-2, osteoprotegerin, runt-related transcription factor-2, and bone Gla protein. Resveratrol alleviated dexamethasone-induced mitochondrial dysfunction. Resveratrol strongly stimulated expression of peroxisome proliferator-activated receptor-γ coactivator 1α and sirtuin-3 genes, as well as their downstream target gene superoxide dismutase-2. Resveratrol induced phosphorylation of AMPK and acetyl-CoA carboxylase (ACC). Blockade of AMPK signaling using compound C reversed the protective effects of resveratrol against dexamethasone. CONCLUSION: Resveratrol showed protective effects against dexamethasone-induced dysfunction of osteoblasts by activating AMPK signaling.

Risk factors for venous thromboembolism following spinal surgery: A meta-analysis.

BACKGROUND: To investigate the risk factors for postoperative venous thromboembolism (VTE) in patients undergoing spinal surgery. METHODS: Literature published in PubMed, Embase, the Cochrane Library, and Web of Science was systematically reviewed to assess risk factors for VTE following spinal surgery. The data analysis was conducted with STATA 12.0. Data were pooled using fixed-effects or random-effects models according to the heterogeneity among the included studies. RESULTS: Twenty-six studies involving 3,216,187 patients were included in this meta-analysis, and the total incidence of VTE after spinal surgery was 0.35% (0.15-29.38%). The pooled analysis suggested that the incidence of VTE after spinal surgery was higher in such aspects as increasing age (weighted mean difference [WMD] 0.55 years, 95% confidence interval [CI] 0.33-0.78, P < .001), female sex (odds ratio [OR] 1.12, 95% CI 1.01-1.25; P = .034), diabetes (OR 1.34, 95% CI 1.29-1.44; P < .001), chronic kidney disease (OR = 8.31, 95% CI 1.98-34.93; P = .004), nonambulatory preoperative activity status (OR 3.67, 95% CI 2.75-4.83; P < .001), D-dimer level (WMD 1.023, 95% CI 0.162-1.884; P = .02), long duration of operation (WMD 0.73, 95% CI 0.21-1.24; P = .006), spine fusion (OR 1.54, 95% CI 1.31-1.82; P < .001), and blood transfusion (OR 2.31, 95% CI 1.73-3.07; P < .001), and the differences were statistically significant. However, there were no significant differences in body mass index, obesity, hypertension, coronary heart disease, spondylolisthesis, intraoperative blood loss, surgical procedures (anterior lumbar interbody fusion vs posterior intervertebral fusion /translaminar lumbar interbody fusion), or surgical site (lumbar vs thoracic) (all P > .05). CONCLUSION: Based on our meta-analysis, we identified several important factors that increased the risk of VTE after spinal surgery. We hope our study provides assistance to spine surgeons so that they can adequately analyze and assess risk factors in patients and then develop preventive measures to reduce the incidence of VTE.

Scheuermann's Disease as a Risk Factor for Lumbar Disc Herniation Recurrence.

OBJECTIVE: To verify whether Scheuermann's disease (SD) is a risk factor for patients with recurrent lumbar disc herniation (rLDH) than in patients without recurrence. STUDY DESIGN: Case-control study. PLACE AND DURATION OF STUDY: Department of Orthopaedics, Yantaishan Hospital, China, from December 2016 to September 2019. METHODOLOGY: The demographics (age, gender, body mass index [BMI], alcohol abuse, and current smoking), diabetes mellitus, and radiological data (affected levels, herniated side, herniation type, Pfirrmann grade, and the presence of SD) of 602 patients were retrospectively analysed, who underwent surgery for symptomatic LDH from December 2016 to August 2018. They were underwent one-year follow-up and were divided into LDH and rLDH groups. Both typical and atypical SD criteria were used to diagnose SD. Independent-sample t-test was used to analyse the role of age and BMI in both groups, and the Chi-square test was conducted to analyse other parameters. Logistic regression analysis was performed to evaluate various factors. RESULTS: There was a significant difference in age (p=0.026), BMI (p=0.007), current smoking (p=0.001), and SD (p<0.001) between the groups. When these parameters were included in the logistic regression analysis, age, current smoking status, and SD were found to be risk factors for rLDH. CONCLUSION: Age, current smoking, and SD are risk factors for rLDH. Older patients with radiological characteristics of SD should quit smoking to prevent rLDH. Key Words: Scheuermann's disease, Kyphosis, Disc herniation, Recurrence, Age, Smoking, Risk factor.

Combined use of tranexamic acid and rivaroxaban in posterior lumbar interbody fusion safely reduces blood loss and transfusion rates without increasing the risk of thrombosis-a prospective, stratified, randomized, controlled trial.

PURPOSE: This prospective, stratified, randomized, single-blind, placebo-controlled multicentre study investigated the safety and effectiveness of reducing blood loss and preventing venous thromboembolism (VTE) during posterior lumbar interbody fusion (PLIF) in patients with stenosis or spondylolisthesis using the combination of tranexamic acid (TXA) and rivaroxaban. METHODS: The Autar score was evaluated in patients after admission. Patients with an Autar score ≤ 10 were randomized to group A or B. Group A was the placebo-controlled group. Patients in group B were treated with 1 g TXA via intravenous injection and 1 g TXA for external use. Patients with an Autar score > 10 were randomized to group C or D. Patients in group C were treated with 10-mg rivaroxaban qd for 35 days after surgery. Patients in group D received the same treatment as those in group B intra-operatively and as those in group C post-operatively. RESULTS: A total of 599 patients from eight hospitals participated in this clinical trial. The total blood loss, intra-operative blood loss, and drainage volume were reduced by the administration of TXA (group A vs group B, P < 0.01; group C vs group D, P < 0.01), and the blood transfusion rate was also decreased (group A vs group B, P < 0.01; group C vs group D, P < 0.01). There were no significant differences (P > 0.05) in the VTE incidence rates among group A and group B. In patients with high-risk thrombosis, the number of patients with VTE was only three and seven after the application of rivaroxaban. Epidural haematoma was not discovered in any patients in our trial. CONCLUSION: The combined application of tranexamic acid and rivaroxaban significantly reduced the amount of blood loss and the transfusion rate during PLIF surgery and avoided an increase in the probability of thrombosis and the occurrence of epidural haematoma. TRIAL REGISTRATION NUMBER AND DATE OF REGISTRATION: ChiCTR-1800016430 2018-06-01.

Up-Regulation of Hsa_circ_0008792 Inhibits Osteosarcoma Cell Invasion and Migration and Promotes Apoptosis by Regulating Hsa-miR-711/ZFP1.

OBJECTIVE: Circular RNA is a newly discovered non-coding RNA. It plays an important role in regulating gene expression, and may take part in tumor progression. This study aimed to investigate the functions of hsa_circ_0008792 in osteosarcoma regulation. METHODS: We identified a circular RNA, hsa_circ_0008792, by using bioinformatics to analyze the GSE96962 dataset. The capacities of migration and invasion were assessed by wound-healing assay and transwell Matrigel assay. The ratios of G0/G1, S, and G2/M phases in cell cycle and apoptosis were measured using flow cytometry. RESULTS: Hsa_circ_0008792 is expressed at low levels in osteosarcoma cells, and up-regulation of hsa_circ_0008792 could suppress osteosarcoma cell migration and invasion and promote apoptosis. This regulation is mediated by hsa-miR-711/ZFP1. The expression level of hsa_circ_0008792 showed no influence on cell cycle of osteosarcoma cells. CONCLUSION: Osteosarcoma is suppressed by hsa_circ_0008792/hsa-miR-711/ZFP1 axis.