The CREB-Smad6-Runx2 axis contributes to the impaired osteogenesis potential of bone marrow stromal cells in fibrous dysplasia of bone.

Fibrous dysplasia (FD) is characterized by the replacement of normal bone with abnormal fibro-osseous tissue. This disorder is due to activating missense mutations in the GNAS gene and resultant over-production of cAMP. However, the signalling pathways that contribute to FD pathogenesis remain unknown. In the current study, bone marrow stromal cells (BMSCs) carrying GNAS R201H mutation were isolated from lesion site of FD patients. cAMP accumulation, enhanced proliferation and impaired osteogenesis potential were observed. Two cell models, BMSCs treated with excess exogenous cAMP and BMSCs infected with lentivirus GNAS R201H, were established to model the pathological conditions of FD and used to investigate its pathogenesis. The results suggest that the CREB-Smad6-Runx2 axis is involved in osteogenesis dysfunction of BMSCs with the FD phenotype. We confirmed the results in FD lesion-derived BMSCs and observed that the impaired osteogenesis potential of BMSCs infected with lentivirus GNAS (R201H) was recovered in vitro through modulation of the CREB-Smad6-Runx2 axis. This study provides useful insight into the signalling pathways involved in the FD phenotype and facilitates dissection of the molecular pathogenesis of FD and testing of novel therapies.

Pyogenic spondylitis caused by Escherichia coli: A case report and literature review.

BACKGROUND: Pyogenic spondylitis is often manifested as atypical low back pain and fever, which makes it easy to be confused with other diseases. Here we report a case of pyogenic spondylitis and describe the diagnosis and treatment based on the related literature. CASE SUMMARY: The reported case suffered from pyogenic spondylitis caused by Escherichia coli and complicated with bacteremia and psoas abscess. Acute pyelonephritis was initially diagnosed due to atypical symptoms. Symptoms were improved from antibiotic treatment while developing progressive lower limb dysfunction. One month post the admission, the patient underwent anterior lumbar debridement + autogenous iliac bone graft fusion + posterior percutaneous screw-rod internal fixation, and received 6 wk of antibiotic treatment after the operation. Reexamination 4 mo post the operation showed that the patient had no evident pain in the waist, and walked well with no evident dysfunction of lower limbs. CONCLUSION: Here we describe the application value of several imaging examinations, such as X-ray, computed tomography and magnetic resonance imaging, and certain tests like erythrocyte sedimentation rate and C-reactive protein in the clinical treatment of pyogenic spondylitis. This disease requires early diagnosis and treatment. Sensitive antibiotics should be used in early stages and surgical intervention should be taken if necessary, which may help for a speedy recovery and prevent the occurrence of severe complications.

[Application of enriched bone marrow compound with fibrin glue in repairing old radial bone defect in rabbits].

OBJECTIVE: To explore the feasibility of using enriched bone marrow (BM) compound with fibrin glue (FG) in repairing old radial bone defect. METHODS: Totally 36 New Zealand rabbits were equally randomized into three groups: simple FG group, BM+FG group, and enriched BM+FG group. A 1.5-cm segmental bone defect was made at the left radial in each animal. After one month, the defect was implanted with the engineered bone. Before implantation, a compound of enriched BM with FG underwent electron microscopy, long-term culture, and bacteriological culture. Four, 8, and 12 weeks after operations, the osteogenetic effect was evaluated using X-ray observation, HE staining, or Van Gieson staining, and a semi-quantitative analysis was performed. RESULTS: Electron microscopy showed enriched BM were compatible well with FG. No bacterial contamination or oncogenicity was observed after long-term culture. X-ray showed the repair effectiveness was significantly higher in BM+FG group and enriched BM+FG group than in simple FG group. Eight and 12 weeks after surgery, the Yang scores were significantly higher in enriched BM+FG group than in BM+FG group [(9.348±0.364évs.(7.984±0.229éìF=40.167ìP=0.001; (12.664±0.388)vs. (10.584±0.836é, F=20.3647ìP=0.004]. In addition, the Yang's scores at bone defects in BM+FG group and enriched BM+FG group were higher at the 12(th) week than in the 8(th) week. (F=36.004ìP=0.001; F=155.141ìP=0.000; respectively)The bone defects were repaired at varied degrees were histologically observed in BM+FG group and enriched BM+FG group during the observations. CONCLUSION: Implantation of BM+FG or enriched BM+FG are effective in repairing old radial bone defects, while simple FG shows not such effect.

Human mesenchymal stem cells promote growth of osteosarcoma: involvement of interleukin-6 in the interaction between human mesenchymal stem cells and Saos-2.

Our previous study showed that exogenous human mesenchymal stem cells (hMSCs) targeted established osteosarcoma and promoted its growth and pulmonary metastasis in vivo. As a follow-up, the present study aimed to investigate how hMSCs would interact with Saos-2 through autocrine/paracrine communication. The results showed that co-injection of hMSCs with Saos-2 into the proximal tibia of nude mice could promote tumor growth and progression. In vitro, the proliferation of Saos-2 and hMSCs was promoted by each other's conditioned medium, in which interleukin-6 (IL-6) played an important role. Osteogenic differentiation of hMSCs could be inhibited by conditioned medium of Saos-2, in which IL-6 was also involved. Furthermore, decreased IL-6 secretion by hMSCs during its osteogenesis and increased IL-6 secretion in response to conditioned medium of Saos-2 were observed. Based on these data, we suggest that there was a positive feedback loop of IL-6 in the interaction between hMSCs and Saos-2.

Loss of Reduction after Cephalomedullary Nail Fixation of Intertrochanteric Femoral Fracture: A Brief Report.

OBJECTIVE: At present, cephalomedullary nail is the most frequently used implant in the management of intertrochanteric fractures around the world. The implant design and fixation techniques of the cephalomedullary nail have been continuously improved to ensure uncomplicated bone union during the past decade. However, a degree of reduction loss during bone healing is still not rare in clinical work. Many attributed this complication to misoperation during the surgery and hold that a series of techniques and tips could help to avoid the loss of reduction. However, until now there has been no research to explore whether the reduction loss after the operation can be fully prevented in the best cases. The purposes of the study are as follows: (i) to evaluate the efficiency of the current established CMN techniques; (ii) to quantify the loss of reduction under an appropriately implanted CMN to anatomically realigned intertrochanteric fractures; and (iii) to explore the possible underlying causes for the inevitable loss of reduction. METHODS: In the retrospective study, 163 consecutive cases with the intertrochanteric fractures fixed with standard cephalomedullary nail technique were reviewed. The anatomical reduction and optimal positioning of the nail were confirmed by postoperative imaging. The fracture types ranged from 31-A1.1-2.3 according to the OTA/AO fracture classification. One hundred and fifteen cases with stable fracture types (31A1.1-2.1) were allocated to Group A, and 48 cases with unstable 31A2.2-2.3 fracture types were allocated to Group B. The radiological measurements included femoral neck shortening, loss of the neck-shaft angle, cutout, and cut-through of the blade. The outcomes between postoperative and 1 year after the operation were evaluated and compared. RESULTS: The patients consisted of 66 males and 97 females with an average age of 69.4 (range: 46-78, SD: 14.6) years. At the 1-year follow-up, no fixation failure or nonunion was observed in each group. The mean femoral neck shortening and loss of the neck-shaft angle were 4.47 mm (range: 0.43-17.68, SD: 3.71) and 5.4° (range: 0.51-19.10, SD: 3.58) separately. The mean cutout and cut-through were 1.84 mm (range: 0.24-11.30, SD: 2.33) and 1.25 mm (range: 0.51-10.29, SD: 1.74). The average femoral neck shortening and loss of the neck-shaft angle were higher in Group B than Group A. Among the 23 cases with the femoral neck shortening more than 10 mm, 19 cases (16.5%) were from Group A and four cases (8.3%) were from Group B. There were nine (7.8%) cases with the loss of the neck-shaft angle more than 10° in Group A and six (12.5%) cases in Group B. CONCLUSIONS: Current established CMN techniques are efficient in treating intertrochanteric femoral fracture. However, even with currently consensual techniques of cephalomedullary nail, the process of fracture healing still risks the loss of reduction, although the migration of the blade could be minimized. This situation may associate with the intrinsic design of the CMN and further improvement is still needed.

Giant Cell Tumor of Tendon Sheath with Tarsal Bones and Intertarsal Joint Invasion: A Case Report.

The giant cell tumor of tendon sheath (GCTTS) is a benign lesion most commonly attached to the tendons and bones of the fingers, hands, and wrists. The involvement of GCTTS to the foot is uncommon. The GCTTS invading tarsal bones and intertarsal joints is not described yet, and the appropriate diagnosis and treatment remain unclear. We report a case of GCTTS with the involvement of tarsal bones and intertarsal joint. Computed tomography scan and magnetic resonance imaging were used to further diagnose and evaluate the quality and range of tumor. The patient was treated with surgical excision of the tumor without application of bone graft. After adequate clearance of the tumor, the patient returned to an asymptomatic walk in 3 months. No malfunction, fracture, or tumor recurrence was found in 2-years follow-up. This report includes clinical, radiologic, histologic diagnostic, and surgical challenges in an unexpected lesion and a review of the literature.

Increased number of mesenchymal stem cell-like cells in peripheral blood of patients with bone sarcomas.

BACKGROUND AND AIMS: The number of peripheral blood mesenchymal stem cells (PBMSCs) may increase under pathological conditions. We sought to compare the number of MSC-like cells in the peripheral blood of patients with bone sarcomas with healthy controls and to analyze related cytokines in the peripheral blood plasma. METHODS: Peripheral blood mononuclear cells (PBMNs) of patients with bone sarcomas and control subjects were isolated for culture and analyzed by flow cytometry for MSC phenotype. Cytokines in the plasma obtained after cell separation were analyzed using enzyme-linked immunosorbent assay (ELISA). Annexin-V and beta-galactosidase staining were used to investigate whether the cells died from apoptosis or senescence. RESULTS: Flow cytometric analysis demonstrated an >9-fold increase in the number of cells with MSC-like phenotypes (CD34(-), CD45(-), CD105(+)) in patients with bone sarcomas compared with control subjects (p<0.05). ELISA results showed that concentrations of hepatocyte growth factor (HGF) and vascular endothelial growth factor (VEGF) in patients with bone sarcomas were statistically higher than those in the control subjects (p<0.05), whereas there was no significant difference in plasma concentrations of leptin and stromal cell-derived factor 1 between the two groups. A significant, positive correlation between the percentages of PBMSC-like cells and concentrations of HGF in all samples (R=0.618; p=0.011). Annexin-V staining of MSC-like cells was positive, whereas beta-galactosidase staining was negative. CONCLUSIONS: Peripheral blood of patients with bone sarcomas has more cells with MSC phenotypes than blood of healthy persons. The increased number is accompanied by increased HGF and VEGF in the plasma.

Human mesenchymal stem cells (hMSCs) target osteosarcoma and promote its growth and pulmonary metastasis.

In an effort to study the interaction between MSCs and osteosarcoma, we established an animal model of primary osteosarcoma in nude mice using Saos-2 cells. hMSCs, labeled with adv-GFP, were injected through the caudal vein. We observed that exogenous hMSCs targeted the osteosarcoma site and promoted its growth and pulmonary metastasis in vivo. To elucidate the underlying mechanisms, we employed transwell, neutralization antibody and MTT assays in vitro. hMSCs migrated toward the conditioned medium from Saos-2 cells, and SDF-1 was involved in this migration. Likewise, Saos-2 cells migrated toward the conditioned medium from hMSCs and CCL5 played an important role in this migration. Furthermore, proliferation of Saos-2 cells was enhanced by the conditioned medium from hMSCs and CCL5 was at least partly responsible for this enhancement.