Yongqing Xu

TLR4 Activation Promotes Bone Marrow MSC Proliferation and Osteogenic Differentiation via Wnt3a and Wnt5a Signaling

Mesenchymal stem cells (MSCs) from adult bone marrow maintain their self-renewal ability and the ability to differentiate into osteoblast. Thus, adult bone marrow MSCs play a key role in the regeneration of bone tissue. Previous studies indicated that TLR4 is expressed in MSCs and is critical in regulating the fate decision of MSCs. However, the exact functional role and underlying mechanisms of how TLR4 regulate bone marrow MSC proliferation and differentiation are unclear. Here, we found that activated TLR4 by its ligand LPS promoted the proliferation and osteogenic differentiation of MSCs in vitro. TLR4 activation by LPS also increased cytokine IL-6 and IL-1β production in MSCs. In addition, LPS treatment has no effect on inducing cell death of MSCs. Deletion of TLR4 expression in MSCs completely eliminated the effects of LPS on MSC proliferation, osteogenic differentiation and cytokine production. We also found that the mRNA and protein expression of Wnt3a and Wnt5a, two important factors in regulating MSC fate decision, was upregulated in a TLR4-dependent manner. Silencing Wnt3a with specific siRNA remarkably inhibited TLR4-induced MSC proliferation, while Wnt5a specific siRNA treatment significantly antagonized TLR4-induced MSC osteogenic differentiation. These results together suggested that TLR4 regulates bone marrow MSC proliferation and osteogenic differentiation through Wnt3a and Wnt5a signaling. These finding provide new data to understand the role and the molecular mechanisms of TLR4 in regulating bone marrow MSC functions. These data also provide new insight in developing new therapy in bone regeneration using MSCs by modulating TLR4 and Wnt signaling activity.

Traumatic spondyloptosis of L4.

Study Design. Case report of 2 patients with traumatic L4–L5 spondyloptosis. Objective. To report the diagnosis and treatment of the traumatic L4–L5 spondyloptosis. Summary of Background Data. Traumatic L4–L5 spondylolisthesis is even rarer than traumatic L5–S1 spondylolisthesis. No case of traumatic L4–L5 spondyloptosis (anterolisthesis of Grade V) has been reported. The injury mechanism and surgery management merit more studies. Methods. Through the posterior approach, both of the 2 patients underwent the decompression and reduction with pedicle screws. One had the posterolateral fusion and the interbody fusion from L4–L5 whereas the other had the posterolateral fusion from L4–S1. Results. Complete reduction and fusion were achieved. The neurologic symptoms improved after the surgery. At follow-ups of 1 year and 6.5 years, there was no further slippage of the vertebrae. They were satisfied with the treatment outcomes. Conclusion. Posterior decompression, reduction, internal fixation, and fusion is effective and dependable for traumatic L4–L5 spondyloptosis.

Single-stage internal fixation for thoracolumbar spinal tuberculosis using 4 different surgical approaches.

Study Design: A retrospective study was conducted on 148 spinal tuberculosis (TB) patients (M:F, 92:56; mean age, 39.7±12.3; range, 16–74 y) treated with anterior debridement and bone graft fusion with nail and screw internal fixation (nails+screws group); posterior pedicle screw fixation (pedicle screw group); vertebral arch pedicle internal fixation through a posterior route (posterior arch fixation group); or posterior debridement, bone graft fusion, and vertebral arch pedicle internal fixation (arch fixation group). Objective: We investigated 4 variant surgical approaches for internal fixation of spinal TB. Summary of Background Data: The effectiveness of single-stage surgical fixation for different degrees of spinal TB is a matter of debate. Methods: Operation time and bleeding volume were recorded. Complications, American Spinal Injury Association (ASIA) score, C-reactive protein, and erythrocyte sedimentation rate were examined preoperatively and 6 months after surgery. Results: Overall, 78, 48, 16, and 6 patients underwent nails+screws, pedicle screws, arch fixation, and posterior arch fixation approaches, respectively. The mean operation times were 175.8±48.8, 308.5±76.7, 143.8±43.0, and 398.3±90.8, respectively (P<0.01). Mean blood transfusion volumes were 1227.1±988.2, 1771.7±794.7, 467.7±123.3, and 2833.3±1083.8 mL, respectively (P<0.01). Primary wound healing was achieved in 127 patients. No patients experienced spinal TB recurrence or failure of bone graft or fixation. All groups achieved significantly improved C-reactive protein and erythrocyte sedimentation rate, but significantly improved ASIA scores were only observed in the nails+screws and pedicle screw groups (P<0.01). Conclusions: Surgical approach limitations and advantages should be considered based on the position and severity of spinal TB infection to maximize functional outcomes and minimize surgical risks.

Wnt11 plays an important role in the osteogenesis of human mesenchymal stem cells in a PHA/FN/ALG composite scaffold: possible treatment for infected bone defect

BackgroundInfected bone defect poses a great challenge for orthopedists because it is difficult to cure. Tissue-engineered bone based on the human mesenchymal stem cells (hMSCs), has currently taken a promising treatment protocol in clinical practice. In a previous study, a porous hydroxyapatite/fibronectin/alginate (PHA/FN/ALG) composite scaffold displayed favorable biological properties as a novel scaffold, which was considered better than single-material scaffolds. In addition, Wnt11 has been demonstrated to play an important role in the development of osteoblasts, but until recently, its role in the osteogenic differentiation of hMSCs in infectious environment remained unclear.MethodsIn this study, we constructed a PHA/FN/ALG composite scaffold with layer-by-layer technology. Furthermore, we also constructed Wnt11-silenced (RNAi) and -overexpressing hMSCs by lentiviral transduction. The gene transduction efficacy was confirmed by quantitative PCR assay and Western blot analysis. Tissue-engineered bone was constructed with hMSCs and PHA/FN/ALG composite scaffolds, and then was implanted into an infected bone defect model for evaluating the osteogenic capacity by quantitative PCR, gross observation, micro-CT and histology analysis.ResultsAll those cells showed similar adhesion abilities and proliferation capacities in scaffolds. After tissue-engineered bone implantation, there were high levels of systemic inflammatory factors in vivo, which significantly declined three days after antibiotic therapy. One or two months after implantation, the results of osteogenic-related gene analyses, gross observation, micro-CT and histology consistently showed that the Wnt11 over-expression hMSC group displayed the strongest osteogenesis capacity, whereas the Wnt11-RNAi hMSC group displayed inferior osteogenesis capacity, when compared with the other cell-containing groups. However, the blank control group and the only composite scaffold without cell implantation group both showed extremely weak osteogenesis capacity.ConclusionOur results revealed that the Wnt11 gene plays an important role in hMSCs for enhancing the osteogenesis in an infectious environment.

Efficacy of combined vancomycin and fosfomycin against methicillin-resistant Staphylococcus aureus in biofilms in vivo.

Infection by methicillin-resistant Staphylococcus aureus (MRSA) is a life-threatening condition, and formation of biofilms can lead to treatment failure in a clinical setting. The aim of this study was to demonstrate the in vivo bactericidal effects of a combination of vancomycin (VAN) and fosfomycin (FOS) against MRSA in a rat carboxymethyl cellulose-pouch biofilm model. The results of the time-kill assay showed that the combination therapy was capable of killing at low minimal inhibitory concentrations (MIC) (½× MIC VAN +1× MIC FOS and 1× MIC VAN + 1× MIC FOS). In the in vivo study, a synergistically bactericidal effect was observed when using the combination therapy on MRSA embedded in the mature biofilm model. In comparison with the untreated control group and the groups receiving either VAN or FOS alone, the rats treated with combination therapy had lower MRSA colony counts in exudates from the pouch, lower white blood cell and neutrophil counts, and C-reactive protein (CRP) in peripheral blood. Furthermore, histological analysis of the pouch wall indicated combination therapy resulted in disappearance of biofilm-like structures, marked decrease in necrosis, and formation of granular tissue. In conclusion, the combination of VAN with FOS had a synergistic bactericidal effect on chronic MRSA infection embedded in biofilm, providing an alternative approach to treating this condition.

Analysis of 17 cases of posterior vertebral column resection in treating thoracolumbar spinal tuberculous angular kyphosis

ObjectiveThis study aims to explore the efficacy and safety of posterior vertebral column resection (PVCR) in treating thoracolumbar spinal tuberculous angular kyphosis (TSTAK).MethodsFrom January 2008 to January 2012, 17 TSTAK patients were treated surgically, including five males and 12 females, with an average age of 23.6 years, among five cases who had the kyphotic apical vertebrae located at the thoracic vertebrae, ten cases were located at the thoracolumbar segment, and two cases were located at the lumbar vertebrae. The kyphotic Cobb angle was measured in the preoperative, postoperative, and final follow-up, respectively, and the nerve function ASIA classification was assessed.ResultsThe mean operative time was 364 min; the average intraoperative blood loss was 2,218 ml; and the average intraoperative blood transfusion was 1,863 ml. Among the five patients with the preoperative nerve function as grade D, four of them recovered to grade E. The preoperative average Cobb angle was 81.3° ± 12.8°, while the postoperative average Cobb average was 17.3° ± 3.6°; while it was significantly improved than the preoperative (P < 0.01), the average kyphosis correction rate was 68.7% ± 6.5%; the postoperative average follow-up was 18.7 months, with an average correction loss as 3.3°.ConclusionPVCR could be safely and effectively used in TSTAK.

Treatment of Aseptic Necrosis of the Lunate Bone (Kienböck Disease) Using a Nickel-Titanium Memory Alloy Arthrodesis Concentrator: A Series of 24 Cases.

Abstract Avascular necrosis of the lunate bone (Kienböck disease) is caused by loss of blood supply of the bone. This study aimed to evaluate the efficacy and safety of a novel nickel–titanium (Ni–Ti) memory alloy arthrodesis concentrator in the treatment of this disease. A consecutive 24 patients with stage IIIb aseptic lunate necrosis were treated with scapho-trapezio-trapezoeid (STT) arthrodesis using a Ni–Ti arthrodesis concentrator from August 2008 to December 2012. Wrist pain, grip strength, carpal height, and scapholunate angle were measured and compared before and after the surgery. The wrist functions were evaluated using the Mayo scale. Patients were followed up for a mean of 12 months (range, 6–24 months). Grip strength of the affected side was significantly improved after the surgery (18 ± 4.74 kg vs. 30.21 ± 7.14 kg, P < 0.0001). Wrist pain score was significantly decreased from 5.88 ± 0.9 to 0.5 ± 0.51 (P < 0.0001). Carpal height and Mayo score were also significantly increased after the surgery (P < 0.0001). Scapholunate angle was significantly decreased after the surgery (68.38 ± 7.28° vs. 49.91 ± 4.28°, P < 0.0001). No implant breakage, loose implant, wound infection, or nonunion occurred. STT arthrodesis is effective for the treatment of stage IIIb lunate necrosis. The Ni–Ti memory alloy arthrodesis concentrator is a convenient tool for STT arthrodesis with excellent and reliable results.

Treatment of scaphoid fractures using a memory alloy nail-feet-fixation device.

Scaphoid fracture is a common carpal fracture, and its treatment often requires fixation devices. This study aimed to investigate the efficacy and safety of a memory alloy nail‐feet‐fixation (MANFF) device in treating scaphoid fractures.