Bone-Targeted Biomimetic Nanogels Re-Establish Osteoblast/Osteoclast Balance to Treat Postmenopausal Osteoporosis.

Insufficient bone formation and excessive bone resorption caused by estrogen deficiency are the major factors resulting in the incidence of postmenopausal osteoporosis (PMOP). The existing drugs usually fail to re-establish the osteoblast/osteoclast balance from both sides and generate side-effects owing to the lack of bone-targeting ability. Here, engineered cell-membrane-coated nanogels PNG@mR&C capable of scavenging receptor activator of nuclear factor-κB ligand (RANKL) and responsively releasing therapeutic PTH 1-34 in the bone microenvironment are prepared from RANK and CXCR4 overexpressed bone mesenchymal stem cell (BMSC) membrane-coated chitosan biopolymers. The CXCR4 on the coated-membranes confer bone-targeting ability, and abundant RANK effectively absorb RANKL to inhibit osteoclastogenesis. Meanwhile, the release of PTH 1-34 triggered by osteoclast-mediated acid microenvironment promote osteogenesis. In addition, the dose and frequency are greatly reduced due to the smart release property, prolonged circulation time, and bone-specific accumulation. Thus, PNG@mR&C exhibits satisfactory therapeutic effects in the ovariectomized (OVX) mouse model. This study provides a new paradigm re-establishing the bone metabolic homeostasis from multitargets and shows great promise for the treatment of PMOP.

Analysis of the associated factors in postoperative wound infection following open reduction and internal fixation for elbow fracture.

Postoperative wound infections (PWIs) following open reduction and internal fixation (ORIF) for elbow fractures can significantly affect patient outcomes. Identifying associated risk factors is crucial for improving clinical practices and patient care. A retrospective analysis (June 2020-June 2023) at our institution involved 90 patients who underwent elbow ORIF. Thirty patients developed PWIs (case group), compared to 60 who did not (control group). Variables like anaemia, operation duration, hospital stay, blood loss, body mass index (BMI), age, hypoalbuminemia, smoking status, diabetes mellitus and open fractures were examined. Univariate and multivariate analyses determined the impact of these variables on PWI incidence, with statistical significance set at p < 0.05. The main pathogens identified were Escherichia coli among Gram-negative bacteria (59.46%) and Staphylococcus aureus among Gram-positive bacteria (40.54%). In the univariate analysis, hypoalbuminemia, anaemia, and lifestyle factors such as smoking showed higher prevalence in patients with PWIs. However, age and length of hospital stay did not significantly influence infection rates. The multivariate analysis further elucidated that anaemia, smoking, diabetes mellitus and open fractures were independent, significant predictors of PWIs. These findings highlight the complexity of factors influencing infection risk post-ORIF, underscoring the importance of both individual health conditions and surgical complications in patient outcomes. Anaemia, smoking, diabetes mellitus and open fractures significantly increase the risk of PWI after elbow ORIF. Early identification and management of these risk factors are imperative to reduce infection rates and improve postoperative recovery.

Lateral locking plate plus antero-posterior lag screws techniques for the management of posterolateral tibial plateau fracture: preliminary clinical results and biomechanical study.

INTRODUCTION: To date, there is no consensus on the optimal surgical strategy for the treatment of posterolateral tibial plateau fracture (PLF). This study introduced a novel, simple technique for treating PLF with a lateral locking plate plus antero-posterior lag screws (LPpLS). METHODS: We conducted a retrospective case series of 42 patients (Female/Male 19/23) with PLF treated with LPpLS between 1 July 2016 and 30 June 2019. Several pre- and postoperative outcomes were recorded, including operative time, intraoperative blood loss, CT findings, HSS, and ROM. For biomechanical studies, seventy synthetic tibiae with a simulated posterolateral split fracture were divided into seven groups. The biomechanical evaluation included displacement measurement at axial compression and fatigue testing. RESULTS: Forty-two eligible patients were followed up for an average of 18 months (range 14-21 months). Postoperative radiographs and CT showed good positioning of plates and screws, no fracture fragment loss, and normal articular surfaces in all 42 cases. The biomechanical study showed that the axial stiffness of LPpLS was in the same fashion as the posterior buttress plate and better than the other fixation methods (P < 0.05). Additionally, the LPpLS group had a smaller displacement of fracture fragments along the X-axis (medial to lateral direction) than the BP group (P < 0.01). CONCLUSIONS: The LPpLS technique could implement good reconstruction of the PLF, showing satisfactory therapeutic effect. The biomechanical evaluation demonstrated that the LPpLS had better stability in three-dimensional directions for PLF than other fixation strategies.

Biomechanical evaluation of percutaneous cement discoplasty by finite element analysis.

BACKGROUND: Percutaneous cement discoplasty (PCD) is a minimally invasive treatment for degenerative lumbar spine disease, but the relationship between decompression effect on the nerve root and different doses of bone cement is uncertain. PURPOSE: To investigate the indirect decompression effect of cement with different doses on nerve roots and the biomechanical changes on the spine during PCD using finite element analysis (FEA). METHODS: FEA was adapted to analyze the mechanical changes in the lumbar vertebrae before and after the application of PCD.CT scan images of adult males were utilized to establish a finite element model of the lumbar vertebral body using mimics and Pro/E software. The images were divided into four models: the normal model (normal, model N), the disc degeneration model (high, model H), the intervertebral disc injected with 3 mL of bone cement (model H1), and the intervertebral disc injected with 5 mL of bone cement (model H2). All models were analyzed using the ABAQUS6.14.2 software. The normal physiological movements were simulated, and the mechanical changes in the lumbar vertebrae were observed prior to and after the cement filling application. RESULTS: The stress of the nerve root in model H was the largest. The nerve root stress in the model H2 was the smallest during flexion, extension, left bending, right bending, left rotation, and right rotation at 90%, 44%, 25%, 56%, 56%, and 51% of the normal benchmark, respectively. After the injection of bone cement, the nerve root stress is reduced. The greater the amount of cement, the lesser the nerve root stress. The motion was reduced in models H, H1, and H2, and there were differences between models H1 and H2. Cartilage endplate stress was less in model H2 than in model H1. CONCLUSIONS: The nerve root stress increased after degeneration and decreased after intervertebral height recovery through cement injection, resulting in a significant indirect decompression effect.The stress of the nerve root decreased with the increase in the amount of cement injection.

The mechanism by which enoxaparin sodium-high-viscosity bone cement reduces thrombosis by regulating CD40 expression in endothelial cells.

OBJECTIVE: PMMA bone cement leads to the development of local thrombi. Our study found that ES-PMMA bone cement, a novel material, can reduce local thrombosis. We used a simple and reproducible animal model to confirm the reduction in local thrombosis and preliminarily explored the associated molecular mechanism. METHODS: New Zealand rabbits, which were used to model thrombosis using extracorporeal carotid artery shunts, were divided into the following three groups, with 10 rabbits in each group: the sham group, PMMA group and ES-PMMA group. Four hours after modelling, experimental samples were collected, and the degree of thrombosis was compared between the groups. The expression of thrombomodulin in endothelial cells was quantified in vascular tissues samples. RESULTS: Thrombosis was observed in the PMMA group and ES-PMMA group but not in the sham group. The thrombosis weight was 0.00732 ± 0.00089 g/cm in the PMMA group and 0.00554 ± 0.00077 g/cm in the ES-PMMA group (P < 0.001). Quantitative real-time polymerase chain reaction (RT-qPCR) and Western blotting revealed that the expression of CD40, which can regulate thrombosis in vascular endothelial cells, was significantly lower in the ES-PMMA group than in the PMMA group. CONCLUSION: Compared with PMMA bone cement, ES-PMMA bone cement can reduce local thrombosis by decreasing the expression of the thrombus-associated regulatory protein CD40 in vascular endothelial cells.

Treatment of Type II Collagen-Induced Rat Rheumatoid Arthritis Model by Interleukin 10 (IL10)-Mesenchymal Stem Cells (BMSCs).

BACKGROUND Rheumatoid arthritis model (CIA) rats were treated by tail vein injection of IL-10-modified bone marrow mesenchymal stem cells (BMSCs) to investigate its feasibility and intrinsic molecular mechanism. MATERIAL AND METHODS The CIA rat model was established by induction type II collagen, and IL-10-modified BMSCs was established by transfecting BMSCs with adenovirus. IL-10-modified BMSCs were used to treat the CIA rats. The therapeutic effect was evaluated by measuring the changes in body weight, ankle swelling, and forced swimming time, as well as observation of synovial hyperplasia and cartilage tissue repair by HE staining. Western blot analysis and ELISA were used to detect gene expression. RESULTS After 4 weeks and 8 weeks of treatment with IL10-BMSCs, the body weight, swelling value, resting time, and forced swimming struggle time of CIA rats were significantly higher than those of BMSCs-treated and -untreated CIA rats (P<0.05). Compared to BMSCs-treated CIA model rats, after treatment with IL10-BMSCs, the repair rate of osteoarticular cartilage was higher and the inhibition of synovial proliferation was better, and serum IL-17, IL-1ß, and TNF-alpha levels were lower. We found that the protein level of SIRT1 in peripheral blood mononuclear cells was lower, the protein level in spleen was higher, and phosphorylation of p65 protein in peripheral blood mononuclear cells was reduced. CONCLUSIONS The efficacy of tail vein injection of IL-10-modified BMSCs in treatment of CIA rats was superior to that of BMSCs alone, which may be related to the more pronounced suppression of IL-10-modified BMSCs in peripheral blood inflammation and spleen immune response.

Benefits and Risks of Subsection Laminectomy with Pedicle Screw Fixation for Ossification of the Ligamentum Flavum of the Thoracic Spine: A Retrospective Study of 30 Patients.

BACKGROUND This study aimed to evaluate the effectiveness of subsection laminectomy with pedicle screw fixation (SLPF) for the treatment of ossification of the ligamentum flavum of the thoracic spine. MATERIAL AND METHODS Thirty patients (age, 40-71 years) with ossification of the ligamentum flavum of the thoracic spine underwent SLPF (13 men, 17 women). Operative time, intraoperative blood loss, preoperative and postoperative change in thoracic kyphosis, and perioperative complications were recorded. The Japanese Orthopedic Association (JOA) score for severity of myelopathy and the American Spinal Injury Association (ASIA) motor and sensory impairment scale were used before and after surgery. RESULTS Mean operative time for SLPF was 208.4±38.3 min and mean intraoperative blood loss was 689.3±171.7 ml. The mean JOA score significantly increased from 5.7±1.9 before surgery to 8.8±2.2 at one month after surgery and 9.3±2.7 at the last follow-up (P<0.01). Postoperative improvement in neurological function increased by 68.3±14.4%. The postoperative ASIA grades significantly improved compared with the preoperative grades (P<0.01). The mean local Cobb angle significantly decreased from 17.8±4.3° before surgery to 15.4±3.6° at one month after surgery and 15.8±3.8° at the last follow-up (P<0.01). Three patients (10%) had operative cerebrospinal fluid (CSF) leak. Postoperatively, one patient had neurological deterioration, two patients had deep venous thrombosis (DVT), and one patient developed a wound infection. CONCLUSIONS SLPF was an effective procedure for the treatment of ossification of the ligamentum flavum of the thoracic spine.

Class IIa HDACs inhibitor TMP269 promotes M1 polarization of macrophages after spinal cord injury.

Spinal cord injury (SCI) is a devastating disease insulting neurological system, and it could be further exacerbated by overwhelming inflammatory responses, where macrophages play a central role. Depending on their heterogeneous phenotypes, macrophages contribute intricately to SCI's pathological processes and functional recovery. Although stimuli like interferons and cytokines are known to regulate their phonotypical transition, it remains elusive which epigenetic programs macrophages engage to complete phenotype shift. We report here that, the treatment of TMP269, a highly selective class IIa HDACs inhibitor, augments the production of pro-inflammatory cytokines in macrophages after SCI, meanwhile, TMP269 also promotes their M1 phenotype activation, which is independent of Th1 or Th2 cytokines. Moreover, TMP269 exacerbates tissue damage and impairs functional recovery after SCI. At last, the adoptive transfer of bone marrow-derived macrophages (BMDMs) overexpressing class IIa HDACs shows beneficial effects in inflammation resolution and functional recovery after SCI. Thus, activating the class IIa HDACs to harness the anti-inflammatory effects of macrophages may represent a potential target to treat SCI.

Baicalin effects on rats with spinal cord injury by anti-inflammatory and regulating the serum metabolic disorder.

Baicalin had neuroprotective effects on inhibiting neuronal cell apoptosis induced by spinal cord ischemic injury. This study aimed to explore the protective effects of Baicalin on rats with spinal cord injury (SCI) and its mechanism of action. The recovery of spinal cord nerve function in rats was evaluated by the Basso, Beattie, and Bresnahan (BBB) score and the combine behavioral score (CBS). The expressions of cytokines tumor necrosis factor α (TNF-α), interleukin-1ß (IL-1ß), and IL-6 were detected by the enzyme-linked immunosorbent assay method. Expressions of inflammation-related proteins were detected by Western blot. Multivariate statistical analysis was performed for serum metabolites. The BBB and CBS score results showed that Baicalin had a certain improvement on rats with SCI. SCI symptoms were significantly improved in low-dose and high-dose groups. The levels of TNF-α, IL-1ß, and IL-6 in the SCI group were significantly increased. The expressions of NF-κB p65, NF-κB p50, p-IκBα, and IKKα in the SCI group showed the opposite trend compared with the low-dose and high-dose groups. Compared with the sham group, glutamine, levels of 3-OH-butyrate, N-acetylaspartate, and glutathione were significantly reduced, and the levels of glutamate and betaine were significantly increased in the SCI group. When Baicalin was administered, the contents of glutamine synthase (GS) and glutaminase (GLS) were significantly reduced, indicating that Baicalin had the effect of improving GS and GLS. Baicalin has protective effects on improving SCI and lower extremity motor function, has a significant anti-inflammatory effect, and regulates the serum metabolic disorder caused by SCI in rats.

NCOA3 Loss Disrupts Molecular Signature of Chondrocytes and Promotes Posttraumatic Osteoarthritis Progression.

BACKGROUND/AIMS: Osteoarthritis (OA) is the most common joint disease. Recently, a novel variant near the nuclear receptor coactivator 3 (NCOA3) has been identified in association with greater risk of developing OA. However, how NCOA3 is regulated in chondrocytes and involved in OA pathogenesis remain elusive. METHODS: The expression and DNA methylation of NCOA3 in knee OA cartilage and in vitro dedifferentiated chondrocytes with or without rs6094710 SNP were analyzed by qRT-PCR, immunoblotting, methylation-specific PCR and bisulfite sequencing. NCOA3 was depleted by siRNA or shRNA or inhibited by a chemical inhibitor to assess its role in chondrocyte dedifferentiation or OA pathogenesis in posttraumatic OA animal model established by cruciate ligament transection surgery. RESULTS: We found that compared with normal counterparts, samples with rs6094710 SNP failed to upregulate NCOA3. Further evidence associated this phenotype with DNMT1-mediated hypermethylation in gene promoter region. Moreover, we showed that NCOA3 maintained the molecular signature of chondrocytes dedifferentiating in vitro or exposed to IL-1ß, nevertheless, NCOA3 appeared dispensable for preventing OA initiation, since NCOA3 loss did not trigger OA in young mice. Instead, NCOA3 loss promoted posttraumatic OA progression, and in parallel, enhanced NF-κB activation. Finally, the promoted posttraumatic OA progression was significantly retarded when administrated with NF-κB pathway inhibitor, suggesting that NCOA3 lose promotes posttraumatic OA at least partially by enhancing NF-κB activation. CONCLUSION: Thus, our findings indicate a critical role of NCOA3 in chondrocytes, and imply that manipulating NCOA3 might present a potential therapeutic approach to interfere OA progression.

Upregulated KAT7 in synovial fibroblasts promotes Th17 cell differentiation and infiltration in rheumatoid arthritis.

Rheumatoid arthritis (RA) is a chronic autoimmune disease involving multiple cellular participants, of which synovial fibroblasts (SFs) are tightly connected with the development and progression of RA. Here, we provide evidence confirming that KAT7, an H4-specific histone acetylase, is upregulated in SFs of RA patients, which is at least attributed to the stimulation by RA-associated proinflammatory cytokines, such as TNF-α, IL-1ß or IFN-γ. In addition, KAT7 overexpression in cultured human fibroblast-like synoviocytes (HFLSs) induces IL-6 and TGF-ß expression through an epigenetic mechanism, and in vitro T helper 17 (Th17) cell polarization cultured in these supernatants shows promoted cell differentiation. Moreover, KAT7 overexpression in HFLSs induces CCL20 expression via p44/42 MAPK pathway, whereby promoting Th17 cell migration. These two activities of KAT7 in RA SFs indicate its potential roles in accelerating RA pathology. Overall, these results demonstrate some connections between KAT7 upregulated in RA SFs and RA progression and present the inhibition of KAT7 activity as a novel therapeutic target for interfering RA disease.

Malicious Tumor? Pathological Fracture of the Femur in Children Caused by Myelolipoma: A Case Report and Review of Literatures.

Myelolipoma is a kind of benign lipoma containing myeloid cells. It is a rare type of tumor that typically presents as an occasional adrenal tumor, generally manifesting as a nonfunctional adrenal mass. Although it can occur in extra-adrenal tissues, its occurrence in bone tissue is extremely rare. Most cases are discovered accidentally during physical examinations of adults, and there are currently no reports of cases with pathological fractures as the main symptoms. We present a case of a 15-year-old teenager who developed a pathological fracture caused by femoral myelolipoma. The diagnosis of the specific type of bone tumor of the patient was determined through pathology and imaging. To treat the condition, we utilized a technique known as the "soft drill" to fully access the tumor space, remove the bone septum, and scrape away the diseased tissue. The fracture was then stabilized using a hybrid external fixation. After a 2-year follow-up period, there was no recurrence of the bone tumor. This case is the first case of intraosseous myelolipoma that occurred in a minor with the initial symptom of pathological fracture, filling the gap in our existing body of knowledge and providing a reference for the treatment of this type of intraosseous myelolipoma.

TiRobot-Assisted Percutaneous Cannulated Screw Fixation for Elderly Patients with Fragility Fractures of the Pelvis: A Retrospective Study.

OBJECTIVE: The incidence of fragility fractures of the pelvis (FFPs) is increasing in the elderly population, and FFPs that require fixation are a challenge for orthopedic surgeons. The insertion of implants is not risk free due to the complex anatomical and osteoporotic bones and requires a steep learning curve. This study aimed to investigate the clinical efficacy of TiRobot-assisted percutaneous cannulated screw fixation in the treatment of elderly FFP patients. METHOD: The clinical data of 46 elderly FFP patients who had been treated with percutaneous cannulated screw fixation from May 2020 to September 2022 were retrospectively analyzed. Twenty-four patients were treated with percutaneous cannulated screw fixation assisted by the TiRobot (TiRobot-assisted group) and 22 patients were treated with conventional freehand surgery (freehand group). Postoperative outcomes, including Matta value, excellent and good rate (EGR) of fracture reduction, and accuracy of screw placement (ASP), were compared. Changes in the Visual analog scale (VAS) pain score and the Majeed score were recorded and compared between groups before and after surgery and during the 24-week follow-up. Repeated-measures analysis of variance (ANOVA) and effect sizes were used as analysis methods. RESULTS: A total of 90 screws were implanted, 51 screws in the TiRobot-assisted group and 39 screws in the freehand group. The operation time of the two groups was 34.1 ± 2.67 min versus 64.5 ± 4.19 min (p < 0.001). There were no screw-related complications or revision surgeries in any group. The Matta value of the TiRobot-assisted group was 5.13 ± 3.52, which was significantly lower than that of the freehand group (9.00 ± 3.68, p < 0.001), while the EGR was 91.67% versus 72.73%, with statistical significance (p < 0.001). The ASP was 100% in the TiRobot-assisted group, better than that in the freehand group, where it was 85.7% (p = 0.043). At each timepoint in the early postoperative period, the VAS score of the TiRobot-assisted group was significantly lower than that of the freehand group and was close to consistent by the last follow-up; the Majeed score of the former was significantly higher than that of the latter at each timepoint of follow-up, with statistical significance (p < 0.001). CONCLUSION: TiRobot-assisted percutaneous cannulated screw fixation of elderly FFP patients is advantageous over conventional freehand surgery, with less invasion, more accurate screw placement, better fracture reduction, early pain relief, and rapid recovery, suggesting that Freehand method to stabilize FFP in the elderly population.

Enoxaparin sodium bone cement displays local anti-inflammatory effects by regulating the expression of IL-6 and TNF-α.

Objective: To explore the roles of Enoxaparin Sodium-Polymethyl methacrylate bone cement on inflammatory factors Interleukin-6 and Tumour Necrosis Factor-α in a rabbit knee replacement model. As well as the mechanisms underlying its potential effects on lipopolysaccharide-induced endothelial cell injury. Methods: A knee replacement model was established using New Zealand rabbits. Forty rabbits were randomly divided into four groups: PMMA, ES-PMMA, sham-operated, and blank control groups (n = 10 in each group). Local tissues around the incision were taken at the 30th, 60th, and 90th minute after the surgical implantation of the corresponding bone cement. Immunohistochemistry in the surgical field was used to measure the expression of local inflammatory factors IL-6 and TNF-α. In the in vitro experiments, 1 cm3 of bone cement was immersed in 3 mL of the medium for 24 h. The bone cement was discarded and diluted to 25% with normal medium. Pre-experiments were screened for the best LPS-inducing concentration of 100 mg/mL, and the most compatible LPS concentration was used for subsequent experiments simulating the primary cultures of rats' Inferior Vena Cava Endothelial Cells. The experiments were divided into four groups: blank control group, LPS induction group, PMMA + LPS group, and ES-PMMA + LPS group. The apoptosis rate was detected by flow cytometry, and the expression levels of TNF-α and IL-6 in the cells and supernatant were measured by ELISA, western blotting, and immunofluorescence. Results: According to immunohistochemical results, IL-6-positive cells were concentrated in the tissue interstitial space. In the PMMA and sham-operated groups, the number of IL-6-positive cells gradually increased over time. At all time points, IL-6 expression in the ES-PMMA group was much lower than in the PMMA and sham-operated groups. At 30 min, TNF-α positive cells in the ES-PMMA group expressed less than those in the PMMA and sham-operated groups, with no discernible difference between the PMMA and ES-PMMA groups at 60 or 90 min. Using ELISA and flow cytometry, the expression levels of IL-6 and TNF-α were improved and the apoptosis rate was magnified in the LPS-induced group (***P < 0.001) in contrast with the blank control group. Additionally, the expression levels of IL-6 and TNF-α were reduced in the ES-PMMA + LPS group compared with the LPS-induced group (*P < 0.05) and the apoptosis rate was reduced (***P < 0.001), with statistically significant variations. Western blotting and immunofluorescence analysis confirmed that IL-6 and TNF-α protein expression in cells was upregulated in the LPS-induced group compared to the blank control group (***P < 0.001), and the mean fluorescence intensity was enlarged (***P < 0.001). Meanwhile, IL-6 and TNF-α expression in the ES-PMMA + LPS group were down-regulated (**P < 0.01 or *P < 0.05) compared with the LPS-induced group and PMMA + LPS crew protein expression, and the average fluorescence intensity of IL-6 and TNF-α was lowered in the ES-PMMA + LPS group compared to the LPS-induced group (***P < 0.001). Conclusions: ES-PMMA bone cement reduced the expression levels of local inflammatory factors IL-6 and TNF-α in a rabbit knee model. ES-PMMA bone cement reduced the rate of LPS-induced endothelial cell apoptosis and diminished local inflammatory damage by regulating the secretion of inflammatory factors TNF-α and IL-6.

ATF2-driven osteogenic activity of enoxaparin sodium-loaded polymethylmethacrylate bone cement in femoral defect regeneration.

BACKGROUND: Polymethylmethacrylate (PMMA) bone cement loaded with enoxaparin sodium (PMMA@ES) has been increasingly highlighted to affect the bone repair of bone defects, but the molecular mechanisms remain unclear. We addressed this issue by identifying possible molecular mechanisms of PMMA@ES involved in femoral defect regeneration based on bioinformatics analysis and network pharmacology analysis. METHODS: The upregulated genes affecting the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) were selected through bioinformatics analysis, followed by intersection with the genes of ES-induced differentiation of BMSCs identified by network pharmacology analysis. PMMA@ES was constructed. Rat primary BMSCs were isolated and cultured in vitro in the proliferation medium (PM) and osteogenic medium (OM) to measure alkaline phosphatase (ALP) activity, mineralization of the extracellular matrix, and the expression of RUNX2 and OCN using gain- or loss-of-function experiments. A rat femoral bone defect model was constructed to detect the new bone formation in rats. RESULTS: ATF2 may be a key gene in differentiating BMSCs into osteoblasts. In vitro cell assays showed that PMMA@ES promoted the osteogenic differentiation of BMSCs by increasing ALP activity, extracellular matrix mineralization, and RUNX2 and OCN expression in PM and OM. In addition, ATF2 activated the transcription of miR-335-5p to target ERK1/2 and downregulate the expression of ERK1/2. PMMA@ES induced femoral defect regeneration and the repair of femoral defects in rats by regulating the ATF2/miR-335-5p/ERK1/2 axis. CONCLUSION: The evidence provided by our study highlighted the ATF2-mediated mechanism of PMMA@ES in the facilitation of the osteogenic differentiation of BMSCs and femoral defect regeneration.

LncRNA MSTRG.22719.16 mediates the reduction of enoxaparin sodium high-viscosity bone cement-induced thrombosis by targeting the ocu-miR-326-5p/CD40 axis.

OBJECTIVE: Polymethylmethacrylate (PMMA) bone cement promotes the development of local thrombi. Our study found that a novel material, ES-PMMA bone cement, can reduce local thrombosis. We used a simple and reproducible animal model to confirm the reduction in local thrombosis and explored the associated molecular mechanism. METHODS: New Zealand rabbits, which were used to model thrombosis using extracorporeal carotid artery shunts, were divided into the following two groups, with 3 rabbits in each group: the PMMA bone cement group and the ES-PMMA bone cement group. Four hours after modelling, experimental samples, including thrombotic and vascular tissues, were collected. Thrombotic samples from the PMMA group and ES-PMMA group were subjected to lncRNA sequencing, and a lncRNA microarray was used to screen the differentially expressed lncRNAs. The expression of thrombomodulin in endothelial cells was quantified in vascular tissue samples. Differences in the lncRNA expression profiles between the thrombotic samples of the PMMA group and ES-PMMA group were assessed by base-to-base alignment in the intergenic regions of genomes. The lncRNA-miRNA-mRNA competitive endogenous RNA (ceRNA) network was established in light of ceRNA theory. Thrombosis was observed in the PMMA group and ES-PMMA group. RESULTS: The thrombotic weight was 0.00706 ± 0.00136 g/cm in the PMMA group and 0.00551 ± 0.00115 g/cm in the ES-PMMA group. Quantitative real-time polymerase chain reaction (RT-q-CR) and Western blotting revealed that the expression of CD40, which can regulate thrombosis in vascular endothelial cells, was significantly lower in the ES-PMMA group than in the PMMA group. High-throughput sequencing was used to identify 111 lncRNAs with lower expression in the ES-PMMA group than in the PMMA group. Through bioinformatics investigation, lncRNA MSTRG22719.16/ocu-miR-326-5p/CD40 binding sites were selected. Fluorescent in situ RNA hybridization (FISH) was performed to verify the lower expression of lncRNA MSTRG.22719.16 in vascular tissues from the ES-PMMA group. A dual-luciferase reporter gene assay was applied to verify that ocu-miR-326-5p binds the CD40 3'-UTR and targets lncRNA MSTRG.22719.16. CONCLUSION: Compared with PMMA bone cement, ES-PMMA bone cement can reduce thrombosis through the lncRNA MSTRG.22719.16/ocu-miR-326-5p/CD40 axis.

Enoxaparin sodium bone cement plays an anti-inflammatory immunomodulatory role by inducing the polarization of M2 macrophages.

OBJECTIVE: The implantation of PMMA bone cement results in an immune response and the release of PMMA bone cement particles causes an inflammatory cascade. Our study discovered that ES-PMMA bone cement can induce M2 polarization of macrophages, which has an anti-inflammatory immunomodulatory effect. We also delved into the molecular mechanisms that underlie this process. METHODS: In this study, we designed and prepared samples of bone cement. These included PMMA bone cement samples and ES-PMMA bone cement samples, which were implanted into the back muscles of rats. At 3, 7, and 14 days after the operation, we removed the bone cement and a small amount of surrounding tissue. We then performed immunohistochemistry and immunofluorescence to observe the polarization of macrophages and the expression of related inflammatory factors in the surrounding tissues. The RAW264.7 cells were exposed to lipopolysaccharide (LPS) for 24 h to establish the macrophage inflammation model. Then, each group was treated with enoxaparin sodium medium, PMMA bone cement extract medium, and ES-PMMA bone cement extract medium, respectively, and cultured for another 24 h. We collected cells from each group and used flow cytometry to detect the expressions of CD86 and CD206 in macrophages. Additionally, we performed RT-qPCR to determine the mRNA levels of three markers of M1 macrophages (TNF-α, IL-6, iNOS) and two M2 macrophage markers (Arg-1, IL-10). Furthermore, we analyzed the expression of TLR4, p-NF-κB p65, and NF-κB p65 through Western blotting. RESULTS: The immunofluorescence results indicate that the ES-PMMA group exhibited an upregulation of CD206, an M2 marker, and a downregulation of CD86, an M1 marker, in comparison to the PMMA group. Additionally, the immunohistochemistry results revealed that the levels of IL-6 and TNF-α expression were lower in the ES-PMMA group than in the PMMA group, while the expression level of IL-10 was higher in the ES-PMMA group. Flow cytometry and RT-qPCR analyses revealed that the expression of M1-type macrophage marker CD86 was significantly elevated in the LPS group compared to the NC group. Additionally, M1-type macrophage-related cytokines TNF-α, IL-6, and iNOS were also found to be increased. However, in the LPS + ES group, the expression levels of CD86, TNF-α, IL-6, and iNOS were decreased, while the expression of M2-type macrophage markers CD206 and M2-type macrophage-related cytokines (IL-10, Arg-1) were increased compared to the LPS group. In comparison to the LPS + PMMA group, the LPS + ES-PMMA group demonstrated a down-regulation of CD86, TNF-α, IL-6, and iNOS expression levels, while increasing the expression levels of CD206, IL-10, and Arg-1. Western blotting results revealed a significant decrease in TLR4/GAPDH and p-NF-κB p65/NF-κB p65 in the LPS + ES group when compared to the LPS group. Additionally, the LPS + ES-PMMA group exhibited a decrease in TLR4/GAPDH and p-NF-κB p65/NF-κB p65 levels when compared to the LPS + PMMA group. CONCLUSION: ES-PMMA bone cement is more effective than PMMA bone cement in down-regulating the expression of the TLR4/NF-κB signaling pathway. Additionally, it induces macrophages to polarize towards the M2 phenotype, making it a crucial player in anti-inflammatory immune regulation.

Impact of sarcopenia and sagittal parameters on the residual back pain after percutaneous vertebroplasty in patients with osteoporotic vertebral compression fracture.

OBJECTIVE: The objective of this study was to explore the impact of sarcopenia and sagittal parameters on the residual back pain (RBP) after percutaneous vertebroplasty (PVP) for treatment of osteoporotic vertebral compression fracture (OVCF). METHODS: This retrospective study included elderly patients (age range 60-90 years) with OVCF treated with PVP from January 2015 and December 2020 in our hospital. The skeletal muscle mass index (SMI) was calculated by dividing the T12 pedicle level muscle cross-sectional area by the square of body height from chest CT to diagnose sarcopenia. The radiological parameters for measuring the sagittal alignment were included: C7-sagittal vertical axis (SVA), T1 pelvic angle (TPA), lumbar lordosis (LL), thoracic kyphosis (TK), pelvic tilt (PT), sacral slope (SS), pelvic incidence (PI). RESULT: According to whether the VAS score > 4, patients were divided into RBP group (56 patients) and Control group (100 patients). There was no difference in age, gender, body mass index, BMD, surgical segment, bone cement usage between the groups (P > 0.05). The SMI in RBP group (27.3 ± 5.1) was significantly lower compared to that in Control group (36.8 ± 3.2) (P < 0.05). Sarcopenia was present in 19 patients (20.3%) in RBP group, which was significantly more than that in Control group (P < 0.05). C7-SVA and TPA was significantly larger in the RBP group than in the Control group (P < 0.05). PI and LL was significantly smaller in the RBP group compared to the Control group (P < 0.05). However, no significant differences between the two groups with respect to TK, SS and PT (P > 0.05). CONCLUSION: Poor sagittal parameters and sarcopenia in OVCF patients after PVP were more prone to residual back pain. Larger C7-SVA, TPA and PI-LL mismatch could increase the incidence of RBP in elderly patients with single-segment osteoporotic compression fractures.

Cement Leakage in Vertebral Compression Fractures Between Unilateral and Bilateral Percutaneous Vertebral Augmentation: A Meta-Analysis.

AIM: Cement leakage remains a significant clinical problem associated with vertebroplasty and kyphoplasty procedures, with uncontrolled cement flow in the posterior direction causing leakage into the vertebral veins or spinal canal that leads to potentially serious clinical complications. This meta-analysis compared the incidences of cement leakage between unilateral and bilateral percutaneous vertebral augmentation (PVA) in the treatment of osteoporosis vertebral compression fractures. MATERIAL AND METHODS: Pertinent studies were identified by a search of the PubMed, Embase, and Web of Science databases up to December 2020. The risk ratio (RR) or weighted mean difference (WMD) was applied to combine the results, and a random-effects or a fixed-effects model was used to pool the results depending on the heterogeneity among studies. Publication bias was estimated using Egger's regression asymmetry test. RESULTS: A total of 16 trials (including 9 RCTs and 7 cohort studies) met the inclusion criteria and were included in this meta-analysis. The incidences of cement leakage were similar between the bilateral PVA and unilateral PVA groups (RR = 0.80, 95%CI: 0.57, 1.11; P = 0.182) but unilateral PVA required less cement volume (WMD = -1.34 ml, 95%CI: -1.87, -0.81; P 0.001). Subgroup analysis revealed that the incidence of cement leakage was significantly lower in the unilateral PKP group than in the bilateral PKP group (RR = 0.65, 95%CI: 0.44, 0.97; P = 0.034). CONCLUSION: The incidences of cement leakage were similar between unilateral and bilateral PVA, but unilateral PVA required less cement. More large-scale studies are needed to verify our findings.

Bone healing study of alendronate combined with enoxaparin sodium bone cement in rabbits with bone defects.

BACKGROUND: To observe the effect of enoxaparin sodium-polymethyl methacrylate (ES-PMMA) bone cement supplemented with alendronate (AN) on bone repair of bone defects in New Zealand rabbits. METHODS: Twenty-seven New Zealand rabbits were randomly divided into ES/AN, ES-PMMA and PMMA groups, with a total of 27 New Zealand rabbits. The drugs loaded in 40 g bone cement powder were as follows: ES/AN group 8000 AxaIU enoxaparin (ES) and 200 mg alendronate (AN), ES-PMMA group 8000 AxaIU enoxaparin (ES), PMMA group without drugs. A bone defect model with a length of 10 mm and a diameter of 5 mm was made from the left tibia of rabbits, and the prepared bone cement was placed in the tibia defect. At 4 weeks, 8 weeks and 12 weeks after the operation, 3 rabbits in each group were sacrificed, and left tibia samples were collected for histological scoring, HE staining and Masson staining. Bone mineral density and new bone volume were measured by imaging, and the related data were processed by one-way ANOVA and least significance difference (LSD) post hoc test. RESULTS: (1) Bone mineral density (BMD, mg/mm3) around the bone defect: at the 4th week, BMD in the ES/AN group was higher than that in the PMMA group; at the 8th week, the BMD in the ES/AN group was significantly higher than that in the other two groups; and at the 12th week, the BMD in the ES/AN group was significantly higher than that in the other two groups. (2) New bone volume (BV, mm3): at the 4th week, BV in the ES/AN group was significantly higher than that in the other two groups, BV in the ES/AN group was significantly higher than that in the other two groups at the 8th and 12th weeks, and BV in the ES-PMMA group was higher than that in the PMMA group. (3) Histological score: at the 4th and 8th weeks, the histological score of the ES/AN group was higher than that of the PMMA group, and at the 12th week, the histological score of the ES/AN group was higher than that of the other two groups. (4) Cortical bone thickness (µm): at the 4th, 8th and 12th weeks, the cortical bone thickness in the ES/AN group was higher than that in the other two groups, and the cortical bone thickness in the ES-PMMA group was higher than that in the PMMA group. (5) The percentage of mature area of new bone in the ES/AN group was higher than that in the other two groups at the 4th week, and at the 8th and 12th weeks, the percentage of mature area of new bone in the ES/AN group and ES-PMMA group was significantly higher than that in the PMMA group. CONCLUSION: (1) Enoxaparin sodium bone cement supplemented with alendronate was superior to enoxaparin sodium bone cement and PMMA bone cement in promoting bone repair of tibial bone defects in New Zealand rabbits. (2) Enoxaparin sodium bone cement is superior to PMMA bone cement in promoting bone repair, showing a certain osteogenic potential.