Modular revision strategy with bispherical augments in severe acetabular deficiency reconstruction.

PURPOSE: Reconstruction of severe acetabular deficiency is extremely challenging in total hip arthroplasty (THA) revisions. Novel bispherical augments were designed to fill acetabular bone loss and facilitate restoration of hip center of rotation (HCOR). Current study aims to compare the outcomes of bispherical augments and tantalum augments. METHODS: Between July 2017 and December 2018, bispherical augments (BA group) were implanted in 25 patients (25 hips) and 22 patients (22 hips) underwent porous tantalum augments (TA group) reconstruction in revision THA. Clinical and radiographic results were evaluated for 25 hips in BA group and 20 hips in TA group at the final follow-up. The mean duration of follow-up was 2.9 years (range, 2.2 ~ 3.7) in BA group and 2.9 years (range, 2.3 ~ 3.8) in TA group. RESULTS: Harris hip scores, HCOR, and leg length discrepancy (LLD) correction did not differ between the treatment groups. The bispherical augments were located more closer to the medial-superior part (zone II) of acetabular shell while the majority of tantalum augments were located at the lateral-superior part (zone I) (P = 0.010). More screws were used in the BA group for augment fixation (mean 2.1 vs. 1.3) (P = 0.000). There was no evidence of loosening or migration in all hips. Only one dislocation occurred in BA group and treated with closed reduction, no recurrence of instability up to the final follow-up. CONCLUSION: The clinical and radiological outcomes of bispherical augments were comparable with tantalum augments; this technique was a reliable alternative method in severe acetabular deficiency reconstruction.

Notch Signaling in Osteogenesis, Osteoclastogenesis, and Angiogenesis.

Skeletal tissue development and regeneration in mammals are intricate, multistep, and highly regulated processes. Various signaling pathways have been implicated in the regulation of these processes, including Notch. Notch signaling is a highly conserved, intercellular signaling pathway that regulates cell proliferation and differentiation, determines cell fate decision, and participates in cellular process in embryonic and adult tissue. Here, we review recent data showing the regulation of Notch signaling in osteogenesis, osteoclastogenesis, and angiogenesis. These processes are cell-context-dependent via direct or indirect mechanisms. Furthermore, Notch signaling may be highly beneficial for efficient coupling of osteogenesis and angiogenesis for tissue engineering and skeletal repair, which is critical to develop clinically therapeutic options.

A Reliable Femoral Osteotomy in Total Hip Arthroplasty for Hartofilakidis Type C Developmental Dysplasia of the Hip: Proximal Femoral Reconstruction.

BACKGROUND: Procedure of the femur is extremely challenging during total hip arthroplasty (THA) for Hartofilakidis type C developmental dysplasia of the hip. The main purpose of this study is to compare the clinical effectiveness of proximal femoral reconstruction (PFR) with subtrochanteric transverse osteotomy (STO). METHODS: Between 2006 and 2015, 33 primary THAs in 26 patients were performed with PFR and 16 hips in 13 patients underwent STO. The mean follow-up was 4.2 (range, 2.2-10.8) years in PFR group and 5.9 (range, 3.5-11.3) years in STO group. At the final follow-up, clinical scores and radiographic results were evaluated for 33 hips in PFR group and 15 hips in STO group. RESULTS: Postoperative Harris hip scores and implant position did not differ between the treatment groups. The mean length of the oblique osteotomy line at proximal femur was 6.9 cm (range, 5.8-7.6 cm) in PFR group. The amount of bone union occurred within 6 months after surgery was 24 (72.7%) hips in PFR group and 9 (60.0%) in STO group. Three major postoperative complications occurred in PFR group, and medial femoral calcar erosion was noted in 1 hip in STO group. CONCLUSION: Similar with STO, the clinical results of PFR technique are a reliable solution for femoral procedure during THA in patients with Hartofilakidis type C developmental dysplasia of the hip.

Direct Anterior Approach for Total Hip Arthroplasty in the Lateral Decubitus Position: Our Experiences and Early Results.

BACKGROUND: The direct anterior approach (DAA) for total hip arthroplasty (THA) is typically performed in the supine position using a specially designed operating room table, which makes this approach more accessible to orthopedic surgeons. We attempted to perform this procedure in the lateral decubitus position on an ordinary operation table to avoid dependence on a special operating room table. There is an obvious absence of literature regarding this subject. METHODS: A total of 248 patients (295 hips) were recruited for primary THAs from July 1, 2014 to December 31, 2014. In total, 126 hips (42.7%) underwent THAs using the DAA in the lateral decubitus position. The technical feasibility and early results were evaluated. RESULTS: The orientation of the acetabular component was 16.5° ± 4.9° anteversion and 43.3° ± 3.5° abduction. Intraoperative proximal femoral fracture occurred in one hip. The superficial wound complications occurred in 2 hips and the hematoma in one hip while in hospital. The lateral femoral cutaneous nerve injury was noted in 43 hips. The early dislocation occurred in 2 hips. Heterotopic ossification was Brooker class I in 5 hips and class II in 1 hip. No aseptic loosening, postoperative periprosthetic fracture, and deep infection occurred in our series. CONCLUSION: The DAA for THA in the lateral decubitus position may be a valuable alternative if the DAA in the supine position is difficult to implement owing to absence of a special operating room table. This technique also seems to provide satisfactory clinical and radiographic outcomes with an acceptable complication in our early follow-up.

Cementless Total Hip Arthroplasty With a High Hip Center for Hartofilakidis Type B Developmental Dysplasia of the Hip: Results of Midterm Follow-Up.

BACKGROUND: Acetabular reconstruction in adults with Hartofilakidis type B developmental dysplasia of the hip is a major technical challenge. The purpose of this retrospective study was to evaluate hip function and radiographic outcomes regarding high hip center at midterm follow-up. METHODS: From January 1, 2007 to December 31, 2009, 37 patients who had Hartofilakidis type B developmental dysplasia of the hip underwent a primary total hip arthroplasty using a high hip center technique. Functional, radiographic, and survivorship outcomes were evaluated. RESULTS: Of the 37 patients, 31 patients (83.8%) were available for the mean follow-up of 6.1 years (range, 1.5-7.6 years). Thirty-one cementless cups were located at an average vertical distance of 38.1 ± 3.3 mm and at a mean horizontal distance of 35.5 ± 3.4 mm. The mean ratio of the height of the hip center was 2.4% (range, 2.0%-2.9%). The Harris Hip Scores were improved from 50.3 points (range, 38-63 points) preoperatively to 92.3 points (range, 85-100 points) at the final follow-up (P < .001). Four patients continued to present with Trendelenburg gait pattern at the last follow-up. With use of revision for any reason and aseptic loosening as the end point, the 5-year survival rates were 90.3% (95% CI, 79.9%-100%) and 93.3% (95% CI, 84.3%-100%), respectively. CONCLUSIONS: The high hip center technique in conjunction with a cementless acetabular component seems to be a valuable alternative to achieve satisfactory midterm outcomes for Hartofilakidis type B developmental dysplasia of the hip.

[Outcome analysis of total hip arthroplasty for traumatic avascular necrosis of femoral head].

OBJECTIVE: To analyze the operative modalities and outcomes of total hip arthroplasty for traumatic avascular necrosis of femoral head (ANFH). METHODS: A retrospective study was conducted for 40 ANFH patients undergoing total hip arthroplasty from January 2007 to October 2011. There were 31 males and 9 females with a mean age of 49 (39-65) years. Their scores of Harris hip score and visual analogue scale (VAS) at pre- and post-operation were recorded to evaluate the clinical outcomes and assess the location of prosthesis by radiology. RESULTS: All of them were followed for an average of 31 (19-51) months. All incisions healed with first intention. There was no prosthetic infection, hip dislocation, deep vein thrombosis or nerve injury. The scores of Harris hip and VAS at Month 1 post-operation and the last follow-up were significantly higher than those preoperative ones (P < 0.05). And the Harris hip score of the last follow-up was also significantly higher than that at Month 1 post-operation (P < 0.05). However, no significant difference existed in VAS score (P > 0.05). The outcomes were excellent (n = 28), good (n = 9) and fair (n = 3) with an excellent and good rate of 92.5%. Possible loosing occurred in 1/11 cemented cases while bone stability was achieved in all 29 cementless cases. And 2 case had Brooker type I heterotopic bone without treatment. CONCLUSION: Total hip arthroplasty for traumatic ANFH can achieve satisfactory clinical efficacies with careful preoperative planning and intraoperative precision.

Study on the Role of Salicylic Acid in Watermelon-Resistant Fusarium Wilt under Different Growth Conditions.

BACKGROUND: Fusarium wilt disease is leading threat to watermelon yield and quality. Different cultivation cropping systems have been reported as safe and efficient methods to control watermelon Fusarium wilt. However, the role of salicylic acid (SA) in watermelon resistance to Fusarium wilt in these different cultivation systems remains unknown. METHODS: in this experiment, we used RNA-seq and qRT-PCR to study the effect of SA biosynthesis on improving watermelon health, demonstrating how it may be responsible for Fusarium wilt resistance under continuous monocropping and oilseed rape rotation systems. RESULTS: the results revealed that the expression of the CIPALs genes was key to SA accumulation in watermelon roots. We observed that the NPR family genes may play different roles in responding to the SA signal. Differentially expressed NPRs and WRKYs may interact with other phytohormones, leading to the amelioration of watermelon Fusarium wilt. CONCLUSIONS: further understanding of gene expression patterns will pave the way for interventions that effectively control the disease.

Fusion in situ versus reduction for spondylolisthesis treatment: grading the evidence through a meta-analysis.

PURPOSE: During surgical procedure on lumbar spondylolisthesis, the role of reducing slip remains controversial. The purpose of the present study was to compare fusion in situ with reduction in clinical and radiographic outcomes. METHODS: A literature research was performed at PubMed, Embase, Web of Science, and Cochrane Library. After screening by two authors, ten articles were brought into this meta-analysis finally, and the quality was evaluated by the modified Newcastle-Ottawa Scale (NOS). Isthmic, moderate, and serious spondylolisthesis were all analyzed separately. Sensitivity analyses were performed for high-quality studies, and the publication bias was evaluated by the funnel plot. RESULTS: Most criteria did not have statistical differences between reduction and fusion in situ groups. However, in reduction group, the union rate was significantly higher (P=0.008), the slippage was much improved (P<0.001) and the hospital stay was much shorter comparing to no-reduction group (P<0.001). Subgroup analysis (containing moderate and serious slip, or isthmic spondylolisthesis) and sensitivity analysis were all consistent with original ones, and the funnel plot indicated no obvious publication bias in this meta-analysis. CONCLUSIONS: Both reduction and fusion in situ for lumbar spondylolisthesis were related with good clinical results. Reduction led to higher rate of fusion, better radiographic slippage, and shorter hospital stay. After sufficient decompression, reduction did not incur additional risk of neurologic impairment compared with fusion in situ.

Wnt Signaling Inhibits High-Density Cell Sheet Culture Induced Mesenchymal Stromal Cell Aging by Targeting Cell Cycle Inhibitor p27.

Mesenchymal stromal cell senescence and apoptosis have been identified as critical molecular hallmarks in aging. In this study, we used stromal cell sheet culture as an in vitro model to study the progressive changes of cellular senescence, apoptosis and underlying mechanism in Wnt3a treated cells. Our results showed fresh bone marrow mesenchymal stromal cells (BMSCs) become senescent and undergo apoptosis with increased inflammatory profile and Reactive Oxygen Species (ROS) in high-density cell sheet cultures. The gene expression level of senescence related proteins and key regulators of apoptosis in cell sheet cultures was significantly increased in older BMSCs at Days 4 and 7 cultures compared with younger cells at Day 1 cultures. More importantly, Wnt signaling activation significantly reduced senescence in cell sheet cultures by direct regulation of cell cycle inhibitor p27. This study not only characterized the cellular and molecular features of aging stromal cells in short-term cell sheet cultures, but also identified the downstream target responsible for Wnt inhibition of cell senescence.

Silencing of RBP­JK promotes the differentiation of bone marrow mesenchymal stem cells into vascular endothelial cells.

Bone marrow mesenchymal stem cells (BM­MSCs) are important for postnatal angiogenesis and are suitable for use in construction of blood vessels by tissue engineering. The present study aimed to investigate the influence of recombination signal binding protein for immunoglobulin kappa J region (RBP­JK) on the differentiation of BM­MSCs into vascular endothelial cells, and to assess the underlying mechanisms. BM­MSCs were isolated and identified by flow cytometry. Lentiviral vectors encoding RBP­JK shRNA (shRBPJK) were constructed to knockdown RBP­JK expression and endothelial differentiation of BM­MSCs was induced. The experimental groups were treated with: empty lentiviral vector (vector group), growth factors (bFGF and VEGF; induced group), shRBPJK (shRBPJK group), and growth factors + shRBPJK (induced + shRBPJK group). The expression of endothelial markers, vascular endothelial growth factor receptor 2 (Flk­1), and von Willebrand factor (vWF) were detected by immunofluorescence. Additionally, in vitro blood vessel formation and phagocytosis were assessed using acetylated LDL, Dil complex and the underlying molecular mechanisms evaluated by western blotting. BM­MSCs were separated and transduced with shRBPJK to reduce RBP­JK expression. Compared with the vector group, the expression of the endothelial cell markers, Flk­1 and vWF, in vitro tubule formation, and phagocytosis ability increased, while the expression levels of p­AKT/AKT and p­NF­κB/NF­κB were significantly decreased (P<0.05) in the induced, shRBPJK, and induced + shRBPJK groups. Compared with the induced group, the expression of Flk­1 and vWF, the number of tubules, and phagocytosis were higher in the induced + shRBPJK group, while the expression levels of p­AKT/AKT and p­NF­κB/NF­κB were lower (P<0.05). Collectively, the present data indicated that silencing of RBP­JK promotes the differentiation of MSCs into vascular endothelial cells, and this process is likely regulated by AKT/NF­κB signaling.

[Effectiveness of proximal femur reconstruction combined with total hip arthroplasty for Crowe type â £ developmental dysplasia of hip].

OBJECTIVE: To investigate the early effectiveness of proximal femur reconstruction combined with total hip arthroplasty (THA) in the treatment of adult Crowe type Ⅳ developmental dysplasia of the hip (DDH). METHODS: Between May 2015 and March 2018, 29 cases (33 hips) suffering from Crowe type Ⅳ DDH were treated with proximal femur reconstruction combined with THA. Of the 29 cases, there were 6 males (7 hips) and 23 females (26 hips), aged from 24 to 74 years with an average age of 44.9 years. The preoperative Harris hip score was 44.0±12.0. Gait abnormalities were found in all of the 33 hips with positive Trendelenburg sign, and the lower limb discrepancy was (3.8±1.6) cm. Preoperative X-ray films and CT both indicated serious anatomical abnormalities, including complete dislocation of the affected hip with significant move-up of the greater trochanter, abnormal development of the femoral neck, abnormal anterversion angle and neck-shaft angle, dysplasia of proximal femur and dysplasia of medullary cavity. The operation time, intraoperative blood loss, transfusion rate, and complications were recorded. The Gruen and DeLee-Charnley zoning methods were used to evaluate the aseptic loosening of the prosthesis on X-ray films. The Harris score was used to evaluate hip function. The lower limb discrepancy was calculated and compared with the preoperative value. RESULTS: The operation time ranged from 80 to 240 minutes, with an average of 124.8 minutes. The intraoperative blood loss ranged from 165 to 1 300 mL, with an average of 568.4 mL. Seventeen patients (51.5%) received blood transfusion treatment. All the incisions healed by first intention without infection or deep vein thrombosis. All patients were followed up 19-53 months, with an average of 33 months. One patient had posterior hip dislocation because of falling from the bed at 4 weeks after operation, and was treated with manual reduction and fixation with abduction brace for 4 weeks, and no dislocation occurred during next 12-month follow-up. Two patients developed sciatic nerve palsy of the affected limbs after operation and were treated with mecobalamin, and recovered completely at 12 weeks later. Trendelenburg sign was positive in 3 patients and mild claudication occurred in 4 patients after operation. X-ray films showed that all the osteotomy sites healed at 3-6 months after operation, and no wire fracture was observed during the follow-up. The Harris score was 89.8±2.8 and lower limb discrepancy was (0.6±0.4) cm at last follow-up, both improved significantly ( t=-22.917, P=0.000; t=11.958, P=0.000). The prosthesis of femur and acetabulum showed no obvious loosening and displacement, and achieved good bone ingrowth except 2 patients who had local osteolysis in the area of Gruen 1 and 7 around the femoral prosthesis, but no sign of loosening and sinking was observed. CONCLUSION: The treatment of Crowe Ⅳ DDH with proximal femur reconstruction and THA was satisfactory in the early postoperative period. The reconstruction technique of proximal femur can effectively restore the anatomical structure of proximal femur, which is one of the effective methods to deal with the deformity of proximal femur.

Quietness Circ 0000962 promoted nerve cell inflammation through PIK3CA/Akt/NF-κB signaling by miR-302b-3p in spinal cord injury.

BACKGROUND: In this study, we analyzed whether the neuroprotection of Circ 0000962 promoted neural inflammation in spinal cord injury (SCI) and its possible mechanism. METHODS: Inflammation factors (TNF-α, IL-1ß, IL-6 and IL-18) were measured using ELIS kit, and NF-κB, PI3K and phosphorylation-(p)-Akt protein expression were analyzed by Western blot analysis. RESULTS: Circ 0000962 expression was decreased in SCI model rat and vitro model. Over-expression of Circ 0000962 decreased inflammation in vitro model of SCI via activation of PI3K/Akt and suppression of NF-κB by down-regulation of miR-302b-3p. Down-regulation of Circ 0000962 promotion inflammation, suppressed NF-κB protein expression, and induced PI3K and p-Akt protein expression in vitro model of SCI by up-regulation of miR-302b-3p. MiR-302b-3p reduced the effect of Circ 0000962 on inflammation in vitro model. CONCLUSIONS: This study showed that Circ 0000962 promoted nerve cell inflammation through Akt/ NF-κB signaling by PI3K in SCI.

Effects of a Coating of Nano Silicon Nitride on Porous Polyetheretherketone on Behaviors of MC3T3-E1 Cells in Vitro and Vascularization and Osteogenesis in Vivo.

To improve the bioperformances of porous polyetheretherketone (PPK) for bone repair, silicon nitride-coated PPK (CSNPPK) was prepared by a method of suspension coating and melt binding. The results revealed that, as compared with PPK, the surface roughness, compressive strength, and water absorption of CSNPPK increased, while the pore size and porosity of CSNPPK exhibited no obvious changes. In addition, the cellular responses (including attachment, proliferation, and differentiation as well as osteogenically related gene expressions) of the MC3T3-E1 cells to CSNPPK were remarkably promoted compared with PPK and dense polyetheretherketone in vitro. Moreover, in the model of rabbit femoral condyle defects, the results of micro computed tomography and histological and mechanical evaluation revealed that the ingrowth of new vessels and bone tissues into CSNPPK was significantly greater than that into PPK in vivo. Furthermore, the load-displacement and push-out loads for CSNPPK with bone tissues were higher than for PPK, indicating good osseointegration. In short, CSNPPK not only promoted vascularization but also enhanced osteogenesis as well as osseointegration in vivo. Therefore, it can be suggested that CSNPPK with good biocompatibility, osteogenic activity, and vascularization might be a promising candidate as an implant for bone substitute and repair.

Notch ligand Jagged1 promotes mesenchymal stromal cell-based cartilage repair.

Placenta-derived mesenchymal stromal cells (PMSCs) provide a promising cell source for tissue regeneration. However, rapid induction of PMSC chondrogenic differentiation during therapeutic transplantation remains extremely challenging. Here we undertook a study to determine if Notch inhibition by soluble Jagged1 (JAG1) peptides could be utilized to accelerate PMSC-induced cartilage regeneration in a mouse post-traumatic osteoarthritis (PTOA) model. Our results showed that treatment of PMSCs with soluble JAG1 significantly enhanced chondrogenesis in culture as shown by increased alcian blue staining and decreased Notch target Hes1 expression when compared to those in lgG-treated control cells. Importantly, significantly enhanced cartilage formation and decreased joint inflammation were observed when JAG1-treated PMSCs were injected into mouse PTOA knee joints. Finally, in vivo cell tracing showed that more JAG1-treated PMSCs remained in knee joint tissues and that JAG1-treated PMSCs exhibited greater PMSC chondrogenic differentiation than lgG-treated control PMSCs at 4 weeks after injection. These data indicate that transient Notch inhibition by soluble JAG1 could be used to enhance PMSC survival and chondrogenic differentiation, thereby increasing the therapeutic potential of PMSCs for cartilage regeneration.

Cementless total hip arthroplasty with extended sliding trochanteric osteotomy for high congenital hip dislocation: A retrospective study.

Total hip arthroplasty (THA) for high congenital hip dislocation (CHD) is technically demanding. The purpose of this retrospective study was to evaluate the results of cementless THA combined with extended sliding trochanteric osteotomy. We also assessed whether chronic low back pain was relieved after surgery.The study included 19 patients (23 hips) with high CHD treated with cementless THA using extended sliding trochanteric osteotomy technique. Clinical and radiographic outcomes were evaluated.Harris Hip Score, WOMAC score, visual analog scale for low back pain and Trendelenburg sign were significantly improved (P < 0.01) compared with the preoperative. Average limb-length discrepancy in the 15 unilateral hips was reduced from 38.2 ±â€Š7.9 mm to 6.7 ±â€Š4.1 mm (P < 0.01). No dislocation, deep vein thrombosis, or infection occurred. Two patients (8.7%) developed sciatic nerve palsy. One (4.3%) developed symptomatic greater trochanteric bursitis. Two (8.7%) sustained proximal femur shaft fracture during implantation of the femoral component. All femoral components showed successful bony ingrowth at the final follow-up. No stem subsidence was detected. There was no acetabular loosening. Bony union of the reattached greater trochanter was obtained in all hips. Wire breakage occurred in 3 hips (13%).Cementless THA with extended sliding trochanteric osteotomy may be appropriate options for patients with high CHD.

Human Mesenchymal Stromal Cell Sheet Enhances Allograft Repair in a Mouse Model.

To determine whether cell sheets generated with long-term passaged (P10) aging human mesenchymal stromal cells (MSCs) could be used for bone tissue regeneration as tissue engineered periosteum in a femoral allograft mouse model similar to fresh passaged (P3) young MSCs. At 3 weeks after transplantation of MSC sheets, results showed more bony callus formed between allograft and host bone ends in both young P3 MSC and aged P10 MSC sheet-wrapped groups when compared to allograft alone. At 6 weeks, while both MSC sheet-wrapped allografts showed more bony callus formation when compared to allograft alone groups, the bony callus size in aged P10 MSC sheet groups was significantly less than young P3 MSC sheet groups. Biomechanical testing confirmed that P3 MSC sheet-grafted femurs had the highest biomechanical strength in the three groups. Histology sections showed that the area of the chondriod callus in the aged P10 MSC sheet groups was significantly larger than in P3 MSC sheet groups. Finally, a significant increase of chondro-osteoclast activity was observed in the P3 MSC sheet-grafted femur. Our data demonstrates that extensive long-term culture-induced MSC aging impaired their osteogenic ability and subsequent bony callus formation, and could be used to induce cartilaginous callus formation.

Notch signaling indirectly promotes chondrocyte hypertrophy via regulation of BMP signaling and cell cycle arrest.

Cell cycle regulation is critical for chondrocyte differentiation and hypertrophy. Recently we identified the Notch signaling pathway as an important regulator of chondrocyte proliferation and differentiation during mouse cartilage development. To investigate the underlying mechanisms, we assessed the role for Notch signaling regulation of the cell cycle during chondrocyte differentiation. Real-time RT-PCR data showed that over-expression of the Notch Intracellular Domain (NICD) significantly induced the expression of p57, a cell cycle inhibitor, in chondrocytes. Flow cytometric analyses further confirmed that over-expression of NICD in chondrocytes enhances the G0/G1 cell cycle transition and cell cycle arrest. In contrast, treatment of chondrocytes with the Notch inhibitor, DAPT, decreased both endogenous and BMP2-induced SMAD 1/5/8 phosphorylation and knockdown of SMAD 1/5/8 impaired NICD-induced chondrocyte differentiation and p57 expression. Co-immunoprecipitation using p-SMAD 1/5/8 and NICD antibodies further showed a strong interaction of these proteins during chondrocyte maturation. Finally, RT-PCR and Western blot results revealed a significant reduction in the expression of the SMAD-related phosphatase, PPM1A, following NICD over-expression. Taken together, our results demonstrate that Notch signaling induces cell cycle arrest and thereby initiates chondrocyte hypertrophy via BMP/SMAD-mediated up-regulation of p57.

Deletion of RBPJK in Mesenchymal Stem Cells Enhances Osteogenic Activity by Up-Regulation of BMP Signaling.

Recently we have demonstrated the importance of RBPjk-dependent Notch signaling in the regulation of mesenchymal stem cell (MSC) differentiation during skeletogenesis both in vivo and in vitro. Here we further performed RBPJK loss-of-function experiments to demonstrate for the first time that RBPJK deficient MSC shows enhanced differentiation and osteogenesis acts via up-regulation of the BMP signaling. In the present study, we first compared the spontaneous and osteogenic differentiation in normal and recombination signal binding protein for immunoglobulin kappa J region (RBPJK) deficient human bone marrow-derived mesenchymal stem cells (MSCs). It was found that RBPJK highly expressed in fresh isolated MSCs and its expression was progressing down-regulated during spontaneous differentiation and even greater in osteogenic media inducted differentiation. Deletion of RBPJK in MSCs not only enhances cell spontaneous differentiation, but also significantly accelerates condition media inducted osteogenic differentiation by showing enhanced alkaline phosphatase (ALP) activity, Alizarin red staining, gene expression of Runx2, Osteopontin (OPN), Type I collagen (COL1a1) in culture. Additionally, BMP signaling responsive reporter activity and phosphor-smad1/5/8 expression were also significantly increased upon removal of RBPJK in MSCs. These data proved that inhibition of Notch signaling in MSCs promotes cell osteogenic differentiation by up-regulation of BMP signaling, and RBPJK deficient MSC maybe a better cell population for cell-based bone tissue engineering.

Meta-analysis of Factor V Leiden G1691A polymorphism and osteonecrosis of femoral head susceptibility.

Testing for genetic risk associations between Factor V Leiden (FVL) and the osteonecrosis of femoral head (ONFH) is common, however, inconsistent results have been previously obtained. To summarize results on the association of FVL mutation polymorphism with ONFH in various populations and to calculate the overall genetic risk factors, we performed a search of electronic databases including PubMed, Elsevier Science Direct, Chinese National Knowledge Infrastructure and the Chinese Biomedical Database to identify published studies correlating the FVL mutation with ONFH. Statistical analysis was performed using Review Manager (RevMan) version 5.0 and Stata statistical software (version 10). We identified 57 titles and included 7 studies comprising 481 cases and 867 controls in this meta-analysis. The groups were pooled, and a significant association between FVL mutation and increased ONFH was found (OR=4.55, 95% CI, 2.75-7.52, P<0.00001). This meta-analysis demonstrated that FVL plays an important role in non-Asian populations. Large sample studies including different ethnic groups and age- and gender-matched groups, as well as multiple gene polymorphism detection should be considered to clarify the association of FVL mutation polymorphism and ONFH susceptibility in the future.