Extracellular vesicles from bone mesenchymal stem cells transport microRNA-206 into osteosarcoma cells and target NRSN2 to block the ERK1/2-Bcl-xL signaling pathway.

Osteosarcoma (OS) is a kind of malignant tumor originating from mesenchymal tissue Bone mesenchymal stem cells-derived extracellular vesicles (BMSCs-EVs) can play important roles in OS. This study investigated the mechanism of BMSCs-EVs on OS. BMSC surface antigens and adipogenic and osteogenic differentiation were detected by flow cytometry, and oil red O and alizarin red staining. EVs were isolated from BMSCs by differential centrifugation and identified by transmission electron microscopy, nanoparticle tracking analysis, and Western blot (WB). miR-206 and neurensin-2 (NRSN2) levels in human osteoblast hFOB 1.19 or OS cells (143B, MG-63, Saos2, HOS) were detected by RT-qPCR. Human OS cells with lower miR-206 levels were selected and treated with BMSCs-EVs or pSUPER-NRSN2. The uptake of EVs by 143B cells, cell proliferation, apoptosis, invasion, and migration were detected by immunofluorescence, 5-ethynyl-2'-deoxyuridine (EdU) and colony formation assays, flow cytometry, scratch test, and transwell assays. The binding sites between miR-206 and NRSN2 were predicted by Starbase database and verified by dual-luciferase assay. The OS xenograft model was established and treated by BMSCs-EVs. Tumor growth rate and volume, cell proliferation, and p-ERK1/2, ERK1/2, and Bcl-xL levels were detected by vernier caliper, immunohistochemistry, and WB. BMSCs-EVs were successfully extracted. miR-206 was diminished and NRSN2 was promoted in OS cells. BMSCs-EVs inhibited proliferation, migration, and invasion, and promoted apoptosis of OS cells. BMSCs-EVs carried miR-206 into OS cells. Inhibition of miR-206 in EVs partially reversed the inhibitory effect of EVs on malignant behaviors of OS cells. miR-206 targeted NRSN2. Overexpression of NRSN2 reversed the inhibitory effect of EVs on OS cells. NRSN2 activated the ERK1/2-Bcl-xL pathway. BMSC-EVs inhibited OS growth in vivo. In summary, BMSC-EVs targeted NRSN2 and inhibited the ERK1/2-Bcl-xL pathway by carrying miR-206 into OS cells, thus inhibiting OS progression.

Combination of Clavicular Hook Plate with Coracoacromial Ligament Transposition in Treatment of Acromioclavicular Joint Dislocation.

OBJECTIVE: To evaluate the clinical efficacy of Arbeitsgemeinschaft für Osteosynthesefragen (AO) clavicular hook plate (CHP) combined with coracoacromial ligament transposition for Rockwood III-V dislocation of AC joint, providing an alternative choice for AC joint dislocation treatment. METHODS: Twenty-five patients diagnosed with Rockwood III-V dislocation of acromioclavicular (AC) joint, including 18 males and seven females, aged 43.5 ± 2.4 years old on average, who had undergone open reduction and AO CHP in combination with coracoacromial (CC) ligament transposition between January 2010 and December 2015, were retrospectively analyzed. Among them, 17 cases were diagnosed as type III, five cases were type IV, and three cases were type V. The surgery mainly included three main steps: bone flap incision, drilling in the clavicle, and hook plate fixation and AC joint reposition. The treatment efficacy was evaluated through clinical examinations and imaging studies for the shoulder joint, including gross observation and measuring coracoid clavicle distance (CC-Dist) using orthophoria X-ray before and 1 year after the surgery, and University of California (UCLA) shoulder rating scale. RESULTS: All the patients were followed up three to four times in 18 months (12-24 months) on average, and the UCLA rating results showed that there were 17 excellent cases (68%), five good cases (20%), and three fair cases (12%). The CC-Dist values after the surgery reduced to 9.7 ± 0.7 mm, which was significantly (P < 0.05) lower compared to that before the surgery (15.8 ± 1.6 mm). Most (88%) of the cases showed almost normal joint function and good anatomical arrangement of the acromioclavicular joint, without any secondary dislocation, and for them, 12 ± 2 weeks on average were needed to regain the normal function of shoulder joint movement. CONCLUSION: Due to the stable fixation, fewer complications, and satisfactory therapeutic effect with great clinical value, the combination of AO CHP and CC ligament transposition is expected to be used for treating Rockwood III-V dislocation of AC joint.

Application of digital technology assisted free ALTPF in reconstruction of large-area soft tissue defect of limbs / 中华显微外科杂志

Objective:To explore the application value of digital technology in free transfer of ALTPF to repair large-area soft tissue defect of limbs.Methods:A total of 13 patients with large-area soft tissue defects of limbs treated from April 2017 to April 2020 were selected in the study, including 9 males and 4 females, aged 39-58 years old. The average age was (42.75±1.94) years old. The area of flap was 16 cm×10 cm-27 cm×18 cm. Before operation, CTA was performed on the donor and recipient areas, and the 3-dimensional image of arterial blood supply in the donor area was obtained by 3-dimensional digital reconstruction technology of CT angiography, so as to clarify the origin, course, classification, length vascular pedicle, of diameter and location of perforating fulcrum of the blood supply of ALTPF. According to the image parameters 3-dimensional, of the defect of the recipient area was reconstructed and designed with Mimics software, and the 3-dimensional digital designed flap was used accurately and standardized during the operation.Results:All the 13 flaps survived without a vascular crisis. The patients entered the follow-up for 6 to 24(mean 16) months by outpatient clinic visits combined with WeChat reviews. At the last follow-up, the surviving flaps had soft texture and good blood supply, the shape and colour of the flap were basically the same as those of normal skin. The limb function recovered well. According to Chinese Medical Association Upper Limb Function Evaluation (TAM) method and Maryland ankle function evaluation method: 8 cases were in excellent, 3 cases were in good and 2 cases were in fair.Conclusion:The preoperative application of digital technology to assist the reconstruction of large-area soft tissue defects of limbs with free ALTPF has high accuracy and standardisation. It improves the quality and success rate of free flap repair. This method is reliable, practical and with clinical value.

Effects of intramedullary nailing fixation on quality of life and joint function in patients with femoral neck fractures.

OBJECTIVE: This study intended to investigate the changes in quality of life and joint function after intramedullary nailing fixation in patients with femoral neck fractures. METHODS: A total of 38 patients with femoral neck fractures received surgical treatment from February 2016 to November 2018 were enrolled as study subjects, and were divided into the intramedullary nailing group (IIN group, n=13) and the plate fixation group (PO group, n=25). The efficacy, general surgical indices, postoperative complications, hip function scores and imaging results were compared between the two groups. RESULTS: The response rate of the IIN group was 100.00%, significantly higher than 72.00% of the PO group (P<0.05). The length of hospital stay, blood loss, and the length of the healing period in the IIN group were lower than those in the PO group (P<0.05). The incidence of infection, deformity, loosening of internal fixation, and failed internal fixation in the PO group were significantly higher those than in the INN group (P<0.05). At 3, 6, and 12 months after surgery, the INN group had higher Harris scores and SF-36 scores than the PO group (P<0.05). The response rates of Harris scores of patients in the IIN group were significantly higher than those in the PO group at 12 months postoperatively (P<0.05). CONCLUSION: Intramedullary nailing fixation in patients with femoral neck fractures has the advantages of a shorter time in bed and better functional recovery, lower incidence of complications and higher long-term joint function with better quality of life.

Overcoming cisplatin resistance in osteosarcoma through the miR-199a-modulated inhibition of HIF-1α.

Dysregulation of miRNAs has been shown to contribute to multiple tumorigenic processes, as well as to correlate with tumour progression and prognosis. miR-199a has been shown to be dysregulated in multiple tumour types. However, the association between miR-199a and the chemoresistance features of osteosarcoma are not well understood, the target genes for miR-199a and the regulatory mechanisms are also unknown. In the present study, we demonstrated that miR-199a is expressed at low levels in osteosarcoma cells and patient samples. By the selection and establishment of cisplatin resistant osteosarcoma cell line, we observed a correlation between miR-199a and cisplatin resistance in osteosarcoma cells: resistant cells exhibit attenuated miR-199a expressions and exogenous overexpression of miR-199a sensitizes osteosarcoma cells to cisplatin. Moreover, we identified HIF-1α as a direct target for miR-199a. Intriguingly, cisplatin resistant osteosarcoma cells display significantly elevated HIF-1α expression under hypoxia. We report here overexpression of miR-199a resensitizes cisplatin resistant cells to cisplatin through inhibition of HIF-1α in vitro and in vivo. Finally, by analysing the clinical osteosarcoma patient samples, we demonstrate a reverse correlation between miR-199a and HIF-1α mRNAs. Our study will provide mechanisms for the miRNA-mediated anticancer therapy and miR-199a may be considered a promising therapeutic agent for osteosarcoma patients who fail to respond to conventional chemotherapy.