Incremental regression of localization context for automatic segmentation of ossified ligamentum flavum from CT data.

PURPOSE: Segmentation of ossified ligamentum flavum (OLF) plays a crucial role in developing computer-assisted, image-guided systems for decompressive thoracic laminectomy. Manual segmentation is time-consuming, tedious, and label-intensive. It also suffers from inter- and intra-observer variability. Automatic segmentation is highly desired. METHODS: A two-stage, localization context-aware framework is developed for automatic segmentation of ossified ligamentum flavum. In the first stage, localization heatmaps of OLFs are obtained via incremental regression. In the second stage, the obtained heatmaps are then treated as the localization context for a segmentation U-Net. Our framework can directly map a whole volumetic data to its volume-wise labels. RESULTS: We designed and conducted comprehensive experiments on datasets of 100 patients to evaluate the performance of the proposed method. Our method achieved an average Dice similarity coefficient of 61.2 ± 7.6%, an average surface distance of 1.1 ± 0.5 mm, and an average positive predictive value of 62.0 ± 12.8%. CONCLUSION: To the best knowledge of the authors, this is the first study aiming for automatic segmentation of ossified ligamentum flavum. Results from the comprehensive experiments demonstrate the superior performance of the proposed method over the state-of-the-art methods.

Role of Primary Cilia in Skeletal Disorders.

Primary cilia are highly conserved microtubule-based organelles that project from the cell surface into the extracellular environment and play important roles in mechanosensation, mechanotransduction, polarity maintenance, and cell behaviors during organ development and pathological changes. Intraflagellar transport (IFT) proteins are essential for cilium formation and function. The skeletal system consists of bones and connective tissue, including cartilage, tendons, and ligaments, providing support, stability, and movement to the body. Great progress has been achieved in primary cilia and skeletal disorders in recent decades. Increasing evidence suggests that cells with cilium defects in the skeletal system can cause numerous human diseases. Moreover, specific deletion of ciliary proteins in skeletal tissues with different Cre mice resulted in diverse malformations, suggesting that primary cilia are involved in the development of skeletal diseases. In addition, the intact of primary cilium is essential to osteogenic/chondrogenic induction of mesenchymal stem cells, regarded as a promising target for clinical intervention for skeletal disorders. In this review, we summarized the role of primary cilia and ciliary proteins in the pathogenesis of skeletal diseases, including osteoporosis, bone/cartilage tumor, osteoarthritis, intervertebral disc degeneration, spine scoliosis, and other cilium-related skeletal diseases, and highlighted their promising treatment methods, including using mesenchymal stem cells. Our review tries to present evidence for primary cilium as a promising target for clinical intervention for skeletal diseases.

RO4929097 regulates RANKL-induced osteoclast formation and LPS-mediated bone resorption.

To investigate the suppressive function of RO4929097, a potent -secretase inhibitor, on RANKL-induced osteoclastogenesis. The cytotoxicity of RO4929097 was evaluated. The suppressive effect and possible molecular mechanism of RO4929097 on RANKL-induced osteoclastogenesis was evaluated both in vitro and in vivo. The IC50 of RO4929097 was 2.93 µM. Treatment with different doses of RO4929097 (100 nM, 200 nM, and 400 nM) effectively reduced osteoclast formation (number and resorption area) in a dose-dependent manner. The qPCR results revealed that RO4929097 attenuates RANKL-induced osteoclast formation and NFATc1 protein expression. The in vivo experiments demonstrated that RO4929097 had an inhibitory effect on LPS-induced bone resorption. Our in vitro experiments showed that RO4929097 can potently inhibit osteoclastogenesis and bone resorption by down-regulating the Notch/MAPK/JNK/Akt-mediated reduction of NFATc1. In accordance with these in vitro observations, RO4929097 attenuated LPS-induced osteolysis in mice. In conclusion, our findings indicate that Notch may represent a potential therapeutic target for the treatment of osteolytic diseases.

LncRNA CASC2 is up-regulated in osteoarthritis and participates in the regulation of IL-17 expression and chondrocyte proliferation and apoptosis.

Long non-coding RNAs (lncRNA) CASC2 is a key player in cancer biology. Our new findings showed that both lncRNA CASC2 and IL-17 were up-regulated in plasma of osteoarthritis patients. Plasma levels of lncRNA CASC2 and IL-17 were significantly and positive correlated only in osteoarthritis patients. Overexpression of lncRNA CASC2 led to up-regulated expression of IL-17 in cells of human chondrocyte cell line CHON-001 (ATCC® CRL-2846™). In addition, overexpression of lncRNA CASC2 inhibited the proliferation, and promoted the apoptosis of chondrocyte. Therefore, lncRNA CASC2 is up-regulated in osteoarthritis and participates in the regulation of IL-17 expression and chondrocyte proliferation and apoptosis.

STK39, overexpressed in osteosarcoma, regulates osteosarcoma cell invasion and proliferation.

Serine/threonine kinase 39 (STK39) is associated with hypertension, autism, Parkinson's disease and various types of cancer in recent years. This study investigated STK39 expression and possible roles in osteosarcoma using qPCR and western blot analysis. Compared to normal bone tissues, the mRNA and protein expression of STK39 was found to be upregulated in osteosarcoma. Using small interfering RNA transfection, STK39 was knocked down into two cell lines of osteosarcoma, U2OS and MG63, and the effects exerted on cell functioning were examined. The results showed that STK39 downregulation inhibited ostesarcoma cell proliferation and invasion. Moreover, STK39 knockdown in osteosarcoma cells significantly affected the expression of proteins connected to cell proliferation (proliferating cell nuclear antigen and p21) and invasion [Twist1, matrix metalloproteinase (MMP)2 and MMP9]. Phosphorylation of Smad2/3 was reduced by STK39 knock down. In conclusion, our data provide evidence that STK39 was overexpressed in osteosarcoma. STK39 may serve as an oncogene by adjusting the proliferation and invasion of osteosarcoma cells.

One-Stage Positron Emission Tomography and Magnetic Resonance Imaging to Assess Mesenchymal Stem Cell Survival in a Canine Model of Intervertebral Disc Degeneration.

Intervertebral disc degeneration (IVDD) is a major health problem. Although mesenchymal stem cells (MSCs) have been used to promote IVD regeneration, the actual survival time of implanted MSCs in IVDs has never been studied noninvasively and continuously in vivo. To investigate survival of implanted MSCs in vivo, this study used a canine model of degenerated IVD and MSCs transfected with a mutant herpes simplex type-1 virus thymidine kinase and labeled with magnetic iron oxide nanoparticles (MION). One-stage positron emission tomography (PET) and magnetic resonance (MR) imaging were carried out 3 days and 2 weeks, 3 weeks, and 4 weeks after implantation of MSCs into IVDs with surgically induced degeneration. Pfirrmann disc degeneration grade determined from the MR images indicated that the repair progress of degenerated IVD stopped 3 weeks after MSC implantation. Meanwhile, MION signal strength, signal contrast ratio (%), and low signal area (mm2) did not change significantly from that seen 3 days after cell implantation until 4 weeks [751.43 (4 weeks) ±52.67 (3 days) vs. 225.34 ± 35.62; 47.37 ± 5.01 vs. 85.37 ± 10.54; 1.78 ± 0.31 vs. 5.29 ± 1.35; P < 0.01, respectively]. Accumulation of the PET reporter probe, 9-(4-[18F]-fluoro-3-hydroxymethylbutyl)-guanine, was dramatically decreased at 3 weeks after MSC implantation. These results demonstrated that MSCs could survive no more than 3 weeks after implantation into IVDs with surgically induced degeneration, suggesting that MSCs could contribute to IVD repair for the first 3 weeks after implantation. The results also indicate that PET imaging could be used reliably to quantify the survival of implanted MSCs, whereas MION with MR imaging would likely be unsuitable for long-term tracking of MSCs in IVDs.

Long non-coding RNA HOTTIP is up-regulated and associated with poor prognosis in patients with osteosarcoma.

Long non-coding RNAs (lncRNAs) have been shown to play key roles in cancer development and progression. In this study, we focused on lncRNA HOTTIP and investigated its expression pattern, clinical significance, and biological function in osteosarcoma (OS). In the present study, lncRNA HOTTIP expression in OS tissues was examined and its correlation with clinicopathological features and patient prognosis was analyzed. In vitro assays were performed to understand the biological roles of lncRNA HOTTIP in OS progression. In the study, we found that HOTTIP expression was up-regulated in OS tissues, and correlated with advanced clinical stage and distant metastasis. OS patients with high HOTTIP expression level had poorer overall survival than those with low HOTTIP expression. Multivariable Cox proportional hazards regression analysis suggested that increased HOTTIP expression was an independent prognostic factor of overall survival in OS patients. Moreover, the results of in vitro assays showed that the suppression of HOTTIP in OS cells significantly reduced cell proliferation, migration and invasion ability. Our study demonstrated that lncRNA HOTTIP play critical roles in OS progression and could represent a novel prognostic marker and potential therapeutic target in OS patients.

Restoration of horizontal stability in complete acromioclavicular joint separations: surgical technique and preliminary results.

BACKGROUND: Our purpose was to investigate the clinical efficacy of arthroscope-assisted acromioclavicular ligament reconstruction in combination with double endobutton coracoclavicular ligament reconstruction for the treatment of complete acromioclavicular joint dislocation. METHODS: During the period from February 2010 to October 2012, ten patients with Rockwood types IV and V acromioclavicular joint dislocation were hospitalized and nine were treated with acromioclavicular ligament reconstruction combined with double endobutton of coracoclavicular ligament reconstruction. The improvement in shoulder functions was assessed using a Constant score and visual analog scale (VAS) system. RESULTS: The mean follow-up period was 33.6 ± 5.4 months. The mean Constant scores improved from 25.2 ± 6.6 preoperatively to 92.4 ± 6.5 postoperatively, while the mean VAS score decreased from 5.9 ± 1.4 to 1.2 ± 0.9; significant differences were observed. The final follow-up revealed that excellent outcomes were achieved in eight patients and good outcome in two patients. CONCLUSION: Arthroscope-assisted acromioclavicular ligament reconstruction in combination with double endobutton of coracoclavicular ligament reconstruction is an effective approach for treatment of acute complete acromioclavicular joint dislocation.

Treatment of osteonecrosis of the femoral head with VEGF165 transgenic bone marrow mesenchymal stem cells in mongrel dogs.

We evaluated the efficacy of vascular endothelial growth factor 165 (VEGF(165)) transgenic bone marrow mesenchymal stem cells (BMSCs) for the repair of early-stage osteonecrosis of the femoral head (ONFH) in mature mongrel dogs. This animal model was surgically established by femoral neck osteotomy and subsequent repinning. Twenty-seven dogs (54 hips) were divided into 3 equal-sized groups: a pCI-neo-VEGF(165) BMSC group, a pCI-neo BMSC group and a core decompression-alone group. The lipofectamine was used to introduce the VEGF(165) gene into the BMSCs. After core decompression, transgenic and non-transgenic autologous BMSCs were implanted. Therapeutic efficacy, including new bone formation and neovascularization in the femoral head, was examined by computed radiography, single-photon emission computed tomography, histological and histomorphometric analysis and immunofluorescent staining for von Willebrand factor in pathological sections. The femoral osteotomy site healed completely by the 4th week after the osteotomy surgery and regions of histologically evident osteonecrosis were found 12 weeks later. A regular arrangement of trabeculae and obvious bone regeneration were observed in the animals receiving implanted VEGF-transgenic BMSCs. The quantity of newly generated capillaries was significantly increased in the pCI-neo-VEGF(165) BMSC group, but there was no significant difference between the pCI-neo BMSC group and the core decompression-alone group. These results demonstrated that VEGF(165) transgenic autologous BMSCs enhanced bone reconstruction and blood vessel regeneration in the ONFH model. Compared with non-transgenic BMSCs, this approach could provide advanced benefits in the treatment of ONFH.

Fate of mesenchymal stem cells transplanted to osteonecrosis of femoral head.

The purpose of this study was to investigate the survival and differentiation status of MSCs transplanted to ONFH. Traumatic ONFH was surgically produced in skeletally mature mongrel dogs. Osteonecrosis was treated with either saline (control) or autologous mesenchymal stem cells (MSCs) transplantation after decompression. Green fluorescent protein (GFP) was used to track the transplanted MSCs, the differentiation of MSCs were evaluated by fluorescent double-labeling with GFP between osteocalcin or von Willebrand factor (vWF) at 2nd, 8th, and 12th week after the transplantation. It was demonstrated that GFP-positive cells were present in the necrotic area up to 12 weeks after the transplantation, their number increased from 15% at 2nd week to 38% at 12th week (p < 0.05). Neither osteocalcin nor vWF was detected by immunocytochemistry in GFP-labeled MSCs in vitro, but osteocalcin was immunohistochemically positive in 90% of the GFP-labeled MSCs in vivo, while vWF was still negative. The vWF expression was of no significant difference between the control group and MSCs-transplanted group. The percentages of trabeculae bone volume were 9.36% and 8.42% at 2nd week (p > 0.05), 22.82% and 14.72% at 8th week, and 31.08% and 20.66% at 12th week (p < 0.05) in MSCs-transplanted group and control group, respectively; new trabeculae bone in MSCs-transplanted group was significantly increased as compared to that of control group at 8th and 12th week. The results demonstrated that the transplanted MSCs could survive, proliferate, and differentiate into osteoblasts directly, which contributed to the accelerated repair process. The possible mechanism is site-dependant differentiation.

The posterolateral shearing tibial plateau fracture: treatment and results via a modified posterolateral approach.

The posterolateral shearing tibial plateau fracture is relatively uncommon and few studies have concentrated on it so far. The purpose of this study was to review the results of surgical treatment of this kind of fracture using a modified posterolateral approach. The clinical results of a case series of 11 patients, collected prospectively, were presented here. At final follow-up 10 out of 11 (91%) patients had satisfactory reduction of the articular surface and all had acceptable alignment. There was neither any loss in reduction or alignment at one year postoperation, with a mean HSS score of 93 (s.d. 3.67, range 84 to 97), nor superficial or deep infections, except that one case had a sanguinous effusion for more than one week postoperatively. It was concluded that the modified posterolateral approach could help to expand the surgical options for an optimal treatment of this kind of fracture, and plating of posterolateral shearing fractures would result in restoration and maintenance of alignment.