Tenascin-C promotes endochondral ossification and fracture healing through Hedgehog and Hippo signaling.

Fractures are frequent and severe musculoskeletal injuries. This study aimed to investigate the function of tenascin-C (TNC) in regulating chondrogenic during fracture healing and elucidate the underlying molecular mechanisms. A well-established femur fracture model in male C57BL/6J mice was used to transect the middle diaphysis of the femur. To identify the essential role of TNC, shTNC lentiviruses or TNC protein were administered in the animal model. Micro-CT analysis, histologic analysis, immunostaining assays, and gene expression analysis were employed to investigate the effect of TNC during fracture healing. An in vitro mesenchymal stem cell culture system was developed to investigate the role and molecular mechanism of TNC in regulating chondrogenesis. TNC expression was induced at the inflammatory phase and peaked at the cartilaginous callus phase during fracture healing. Knockdown of TNC expression in callus results in decreased callus formation and impaired fracture healing. Conversely, administration of exogenous TNC promoted chondrogenic differentiation, cartilage template formation and ultimately improved fracture healing. Both the Hedgehog and Hippo signaling pathways were found to be involved in the pro-chondrogenic function of TNC. Our observations demonstrate that TNC is a crucial factor responsible for endochondral ossification in fracture healing and provide a potential therapeutic strategy for promoting fracture healing.

LncRNA XIST facilitates S1P-mediated osteoclast differentiation via interacting with FUS.

INTRODUCTION: The diagnosis and treatment of osteoporosis, a frequent age-related metabolic bone disorder, remain incomprehensive and challenging. The potential regulatory role of lncRNA XIST and sphingosine kinase 1 (SPHK1) pathway need experimental investigations. MATERIALS AND METHODS: RAW264.7 cells and BMMs were obtained for in vitro studies and 30 ng/mL RANKL was implemented for induction of osteoclast differentiation. The suppressing of lncRNA XIST, SPHK1 and fused in sarcoma (FUS) was achieved using small hairpin RNA, while overexpression of XIST and FUS was constructed by pcDNA3.1 vector system. Tartrate-resistant acid phosphatase (TRAP) staining was used for observation of formation of osteoclasts. RNA-pulldown analysis and RNA binding protein immunoprecipitation (RIP) was implemented for measuring mRNA and protein interactions. RT-qPCR was conducted to determining mRNA expression, whereas ELISA and Western blotting assay was performed for monitoring protein expression. RESULTS: RANKL induced osteoclast differentiation and upregulated expression of osteoclastogenesis-related genes that included NFATc1, CTSK, TRAP and SPHK1 and the level of lncRNA XIST in both RAW264.7 cells and BMMs. However, knockdown of lncRNA XIST or suppressing SPHK1 significantly reserved the effects of RANKL. LncRNA XIST was further demonstrated to be interacted with FUS and increased the stability of SPHK1, indicating its ability in promoting osteoclast differentiation through SPHK1/S1P/ERK signaling pathway. CONCLUSION: LncRNA XIST promoted osteoclast differentiation via interacting with FUS and upregulating SPHK1/S1P/ERK pathway.

TNF-α/STAT3 pathway epigenetically upregulates Nav1.6 expression in DRG and contributes to neuropathic pain induced by L5-VRT.

BACKGROUND: Studies showed that upregulation of Nav1.6 increased the neuronal excitability and participated in neuropathic pain in the dorsal root ganglion (DRG). However, the molecular mechanisms underlying Nav1.6 upregulation were not reported yet. METHODS: The paw withdrawal threshold was measured in the rodents following lumbar 5 ventral root transection (L5-VRT). Then qPCR, western blotting, immunoprecipitation, immunohistochemistry, and chromatin immunoprecipitation assays were performed to explore the molecular mechanisms in vivo and in vitro. RESULTS: We found that the levels of Nav1.6 and phosphorylated STAT3 were significantly increased in DRG neurons following L5-VRT, and TNF-α incubation also upregulated the Nav1.6 expression in cultured DRG neurons. Furthermore, immunoprecipitation and chromatin immunoprecipitation assays demonstrated that L5-VRT increased the binding of STAT3 to the Scn8a (encoding Nav1.6) promoter and the interaction between STAT3 and p300, which contributed to the enhanced transcription of Scn8a by increasing histone H4 acetylation in Scn8a promoter in DRG. Importantly, intraperitoneal injection of the TNF-α inhibitor thalidomide reduced the phosphorylation of STAT3 and decreased the recruitment of STAT3 and histone H4 hyperacetylation in the Scn8a promoter, thus subsequently attenuating Nav1.6 upregulation in DRG neurons and mechanical allodynia induced by L5-VRT. CONCLUSION: These results suggested a new mechanism for Nav1.6 upregulation involving TNF-α/STAT3 pathway activation and subsequent STAT3-mediated histone H4 hyperacetylation in the Scn8a promoter region in DRG, which contributed to L5-VRT-induced neuropathic pain.

[Correlation of adult spinal sagittal imbalance and life quality].

OBJECTIVE: To evaluate the correlation of spinal sagittal imbalance and life quality. METHODS: Radiographic analysis for 48 consecutive symptomatic patients with spinal sagittal imbalance was performed with posteroanterior and lateral standing radiographs. There were 12 males and 36 females with an average age of (66.2 ± 8.5) yrs. The measurement parameters included C7PL, thoracic kyphosis (TK), thoracolumbar kyphosis (TLK), lumbar lordosis (LL), pelvic tilt (PT), pelvic incidence (PI) and sacral slope (SS). Life quality was assessed with SF-36 questionnaire. Pearman's method was employed to analyze the correlation. RESULTS: Mean C7PL was (44.7 ± 22.5) mm, TK (26.1 ± 13.1)°, TLK (11.9 ± 10.3)°, LL (23.5 ± 18.2)°, PT (32.1 ± 13.4)°, PI (57.4 ± 10.9)° and SS (22.5 ± 11.5)°. C7PL had a significant correlation with physical functioning (r = -0.428, P < 0.01) and general health (r = -0.428, P < 0.01). PI had a significant correlation with bodily pain (r = -0.374, P < 0.01), vitality (r = -0.303, P < 0.01), social functioning (r = -0.309, P < 0.01) and role emotional (r = -0.429, P < 0.05). TK had a significant correlation with physical functioning (r = -0.292, P < 0.05) and general health (r = -0.389, P < 0.01). LL had a significant correlation with physical functioning (r = 0.428, P < 0.01), general health (r = 0.340, P < 0.05) and vitality (r = 0.373, P < 0.01). PT had significant correlation with vitality (r = -0.385, P < 0.01) and social functioning (r = -0.417, P < 0.05). No significant correlation existed between TLK, SS and SF-36 categories. CONCLUSION: C7PL, TK, LL, PI and PT are significant parameters correlating with quality of life. PI is the most important one affecting bodily pain. TK, LL and C7PL are the main parameters affecting general health. PI, PT and LL affect vitality the most. Correcting these parameters while treating sagittal imbalance is important for a better life quality.

CXCL12/CXCR4-Rac1-mediated migration of osteogenic precursor cells contributes to pathological new bone formation in ankylosing spondylitis.

Ankylosing spondylitis (AS) is a chronic inflammatory disease characterized by inflammatory back pain and spinal ankylosis due to pathological new bone formation. Here, we identified CXCL12 as a critical contributor to pathological new bone formation through recruitment of osteogenic precursor cells (OPCs). CXCL12 was found highly expressed in the regions that would potentially develop pathological new bone. OPCs were recruited to the regions where CXCL12 was up-regulated. Inhibition of CXCL12/CXCR4 axis with AMD3100 or conditional knockout of CXCR4 attenuated OPCs migration and subsequent pathological new bone formation in animal models of AS. By contrast, a genetically engineered animal model with CXCL12 overexpression developed a joint ankylosis phenotype. Furthermore, Rac1 was found essential for OPCs migration and pathological new bone formation. These findings ravel the novel role of CXCL12 in AS and indicate a potential strategy for targeting the CXCL12/CXCR4-Rac1 axis to prevent progression of axial skeleton ankylosis.

Role of death receptor, mitochondrial and endoplasmic reticulum pathways in different stages of degenerative human lumbar disc.

Intervertebral disc (IVD) cell apoptosis has been suggested to play an important role in promoting the degeneration process. It has been demonstrated that IVD cell apoptosis occurs through either death receptor, mitochondrial or endoplasmic reticulum (ER) pathway. Our study aimed to explore the relationship among these three pathways and grade of IVD degeneration (IVDD). IVDs were collected from patients with lumbar fracture, vertebral tumor, disc herniation or spondylolisthesis. IVDs were distinguished by MRI and histomorphological examination, cell apoptosis was detected by TUNEL staining. Biomarkers of these three apoptosis pathways were detected by RT-PCR and Western blot. Furthermore, the correlation between apoptosis pathways biomarkers and disc pathology were analyzed. Nucleus pulposus cell density decreased with degeneration process, and increased apoptotic ratio. ER pathway was predominant in mild stage of IVDD (GRP78, GADD153 upregulation and caspase-4 activation), death receptor pathway was predominant in mild and moderate stages (Fas, FasL up-regulation and caspase-8 activation) and mitochondrial pathway was predominant in moderate and severe stages (Bcl-2 down-regulation, Bax up-regulation, cytochrome-c accumulation in cytoplasm and caspase-9 activation). There were significant differences in the expressions of Fas, FasL, Bax, GADD153, cytochrome-c and cleaved caspase-8/9/3 between contained and non-contained discs. In conclusion, apoptosis occurs via these three apoptosis pathways together in IVDD. ER pathway plays a more critical role in the mild compared to moderate and severe stages, death receptor pathway in mild and moderate, and mitochondrial pathway in moderate and severe stages of IVDD. Disc cells apoptosis may progress rapidly after herniation, and may depend on the type of herniation.

[Experimental study of percutaneous vertebroplasty with a novel bone void filling container system].

OBJECTIVE: To investigate vertebral augmentation with a novel reticulate bone filling container system by polymethyl methacrylate (PMMA) injection in cadaveric simulated vertebral compressive fracture and explore the effect of reticulate bone filling container on cement distribution controlling within vertebral body and the restoration of biomechanical properties after augmentation. METHODS: A total of 28 freshly frozen human vertebrae specimens were randomly divided into 4 groups. After the measurements of bone mineral density (BMD) and vertebral height, each vertebra received an axle load by a MTS (material testing system) machine to test the initial strength and stiffness. Subsequently a simultaneous compressive fracture model was created to measure the stiffness and height of fractured vertebrae. Then the augmentation procedure was performed. Afterward the biomechanical properties and the vertebral height were similarly measured as pre-operatively. The expansion of bone filling container and the distribution of cement within vertebral body were morphologically observed by crossing the specimens in sagittal midline and also integrated with the radiographic results. RESULTS: Stiffness was significantly restored comparing with that of fractured level (P < 0.05). And the bipedicular groups had better restoration results than the unipedicular groups. The strength and height of specimens significantly increased after the augmentation procedure but without difference among groups. In axial radiographic view, the distribution of cement in vertebral body was oval or long oval-shaped in double-layer bone filling container groups while it was irregular in single-layer groups. After crossing, the double-layer version expanded well in vertebral body and could enwrap most of injected cement. There was only a little leakage near the vessel layer. But the single-layer version had a poor expansion and a large amount of cement leakage. CONCLUSION: This novel reticulate bone void filling container system with different layers may restore both the biomechanical properties and the height of fractured vertebrae. But, with the benefit of reducing cement leakage, a double-layer design can enwrap most of injected PMMA and has a brighter prospect of clinical application.

BRD4 promotes heterotopic ossification through upregulation of LncRNA MANCR.

AIMS: Acquired heterotopic ossification (HO) is a debilitating disease characterized by abnormal extraskeletal bone formation within soft-tissues after injury. The exact pathogenesis of HO remains unknown. It was reported that BRD4 may contribute to osteoblastic differentiation. The current study aims to determine the role of BRD4 in the pathogenesis of HO and whether it could be a potential target for HO therapy. METHODS: Achilles tendon puncture (ATP) mouse model was performed on ten-week-old male C57BL/6J mice. One week after ATP procedure, the mice were given different treatments (e.g. JQ1, shMancr). Achilles tendon samples were collected five weeks after treatment for RNA-seq and real-time quantitative polymerase chain reaction (RT-qPCR) analysis; the legs were removed for micro-CT imaging and subsequent histology. Human bone marrow mesenchymal stem cells (hBMSCs) were isolated and purified bone marrow collected during surgeries by using density gradient centrifugation. After a series of interventions such as knockdown or overexpressing BRD4, Alizarin red staining, RT-qPCR, and Western Blot (Runx2, alkaline phosphatase (ALP), Osx) were performed on hBMSCs. RESULTS: Overexpression of BRD4 enhanced while inhibition of Brd4 suppressed the osteogenic differentiation of hBMSCs in vitro. Overexpression of Brd4 increased the expression of mitotically associated long non-coding RNA (Mancr). Downregulation of Mancr suppressed the osteoinductive effect of BRD4. In vivo, inhibition of BRD4 by JQ1 significantly attenuated pathological bone formation in the ATP model (p = 0.001). CONCLUSION: BRD4 was found to be upregulated in HO and Brd4-Mancr-Runx2 signalling was involved in the modulation of new bone formation in HO. Cite this article: Bone Joint Res 2021;10(10):668-676.

Molecular Imaging of Collagen Destruction of the Spine.

As the leading cause of disability worldwide, low back pain is commonly caused by biomechanical and catabolic disruptions to key structures of the spine, such as intervertebral discs and facet joints. To date, accurate, noninvasive detection of microdestruction within these tissues remains an elusive goal. Here, we report an in vivo imaging approach based on a collagen hybridizing peptide (CHP) that specifically targets disruption to the extracellular matrix architecture at the molecular scale─the denatured collagen molecules. Utilizing fluorescently labeled CHPs, live animal imaging, and light sheet fluorescence microscopy, we mapped collagen destruction in the lumbar spines in 3D, revealing that under normal conditions collagen destruction was localized to load-bearing anatomical structures including annulus fibrosus of the disc and the facet joints, where aging, tensile force (hindlimb suspension), and disc degeneration (needle puncture) escalated the CHP-binding in specific mouse models. We showed that targeting denatured collagen molecules allowed for an accurate, quantifiable interrogation of the structural integrity of these spinal matrixes with a greater sensitivity than anatomical imaging and histology. Finally, we demonstrated CHP's binding to degenerated human discs, suggesting exciting potentials for applying CHP for diagnosing, monitoring, and treating various spinal disorders, including intervertebral disc degeneration, facet joint osteoarthritis, and ankylosing spondylitis.

Comprehensive expression profiles of CircRNAs, LncRNAs, and mRNAs in PBMCs from patients with the ossification of the posterior longitudinal ligament

Ossification of the posterior longitudinal ligament (OPLL), one of spinal disease causing myelopathy, is characterized by the ectopic ossification and narrowing of the spinal cord. However, the pathogenesis of OPLL is largely unclear. In this study, transcriptome expression profiles (circRNAs, lncRNAs, and mRNAs) were identified via high-throughput sequencing using peripheral blood mononuclear cells (PBMCs) from OPLL and non-OPLL patients. We found that 1150 mRNAs, 331 circRNAs, and 1429 lncRNAs were significantly differentially expressed in the PBMCs of OPLL patients. GO and KEGG enrichment analyses revealed that most mRNAs were associated with inflammation. The co-expression networks indicated that circRNAs and lncRNAs could regulate the mRNAs through influencing the inflammation of OPLL. The circRNA-miRNA-mRNA integrated network showed that circRNA-regulated mRNAs associated with TGF-ß and TNF-α signaling pathways. These analyses indicate that circRNAs, lncRNAs, and mRNAs from PBMCs might contribute to inflammation in OPLL.

The OLIF working corridor based on magnetic resonance imaging: a retrospective research.

OBJECTIVE: To provide an anatomical basis for the development of oblique lumbar interbody fusion (OLIF) in Chinese patients. METHODS: Between November 2018 and June 2019, 300 patients' lumbar MRI data were reviewed. According to the Moro system and zone method described by us, the axial view was vertically divided into 6 zones (A, I II, III, IV, P) and was horizontally divided into 4 zones (R, a, b, c, L). The locations of left psoas muscle and the major artery at L2/3, L3/4, and L4/5 levels were evaluated by the grid system. The aortic bifurcation segments will also be evaluated at the level of the vertebral body or the disc. RESULTS: At the L2/3 level, left psoas muscle and the major artery in zone Ib were found in 28.0% of subjects, in zone IIb in 20.3%, and in zone Ic in 20.0%; at the L3/4 level, in zone Ab in 20.7% of subjects, in zone Ac in 26.0%, and in zone Ic in 11.0%; and at the L4/5 level, areas in zone Ab in 31.0% of subjects, in zone Ac in 26.0%, and in zone Ib in 11.7%. The aortic bifurcation segments were mainly at the L4 level. The zone of the left psoas muscle at all levels, the zone of the major artery at L4/5 level, and the zone of the aortic bifurcation segments had significant correlation with gender difference (P < 0.05). CONCLUSION: The left-sided OLIF at L2-L5 disc levels can be a feasible type of surgery for lumbar interbody fusion in the majority of Chinese patients. Before the operation, in order to screen out the appropriate surgical approach, routine lumbar magnetic resonance imaging is recommended to analyze the patient's local anatomical features.

Aberrant upregulation of CaSR promotes pathological new bone formation in ankylosing spondylitis.

Pathological new bone formation is a typical pathological feature in ankylosing spondylitis (AS), and the underlying molecular mechanism remains elusive. Previous studies have shown that the calcium-sensing receptor (CaSR) is critical for osteogenic differentiation while also being highly involved in many inflammatory diseases. However, whether it plays a role in pathological new bone formation of AS has not been reported. Here, we report the first piece of evidence that expression of CaSR is aberrantly upregulated in entheseal tissues collected from AS patients and animal models with different hypothetical types of pathogenesis. Systemic inhibition of CaSR reduced the incidence of pathological new bone formation and the severity of the ankylosing phenotype in animal models. Activation of PLCγ signalling by CaSR promoted bone formation both in vitro and in vivo. In addition, various inflammatory cytokines induced upregulation of CaSR through NF-κB/p65 and JAK/Stat3 pathways in osteoblasts. These novel findings suggest that inflammation-induced aberrant upregulation of CaSR and activation of CaSR-PLCγ signalling in osteoblasts act as mediators of inflammation, affecting pathological new bone formation in AS.

The effect of screw length and bone cement augmentation on the fixation strength of iliac screws: a biomechanical study.

STUDY DESIGN: Comparison of the biomechanical fixation strengths offered by 3 iliac screw fixation techniques: short screw, short screw augmented with cement, and long screw. OBJECTIVE: Evaluate the effect of screw length and bone cement augmentation on the fixation strength of iliac screw upon fatigue loading. SUMMARY OF BACKGROUND DATA: Iliac screws have been used in treating spinal disorders such as spinal deformity, spondylolisthesis, and sacral tumor. In clinical practices, both short screws and long screws are being used. It has been reported that short iliac screws have a higher rate of loosening. Therefore, short iliac screws are being used with bone cement augmentation to improve fixation. To date, no biomechanical study has compared the strengths of these 3 different iliac screw fixation techniques. METHOD: Fresh, frozen human cadaveric pelvis specimens (n = 18, 12 males, 6 females, average age 61 y) were used. Bone density was measured to characterize bone quality. The specimens were randomly divided into 2 groups. In group 1 (n = 8), short screws of 7.0-mm diameter and 70 + or - 4 mm length (as the length of exceeding over ischial notch) and long screw of 7.0-mm diameter and 120 + or - 4 mm length were placed on either side of the pelvis (left and right). In group 2 (n = 10), short iliac screws were placed after augmentation with polymethyl methacrylate bone cement on 1 side of the pelvis and long iliac screw were placed on the other side (left and right). Cyclic loading ranging from 20 to 200 N was applied to each screw at a frequency of 2 Hz up to 5000 cycles. Pullout tests were then conducted at the rate of 5 mm/min after the fatigue test, and the maximum pullout strength for each screw was recorded and analyzed. RESULTS: The maximum pullout strength of the long screw and short screw groups after fatigue conditioning were 2386 + or - 1470 and 833 + or - 681 N respectively. Significant difference was found between the 2 groups (P < 0.05). The short iliac screw had a higher loosening rate. The pullout force of the short screw fixation with augmentation and the long screw fixation after cyclic loading were 2436 + or - 915 and 2529 + or - 1055 N, respectively. No significant difference was found between the 2 groups (P > 0.05). CONCLUSIONS: Short iliac screws are susceptible to loosening after cyclic loading. Bone cement augmentation of short screws has demonstrated a significant increase in the fixation strength of short screws to an extent similar to that of long iliac screws. Thus, short iliac screw fixation after augmentation with bone cement will be a viable clinical option for spino-pelvic reconstruction.

[Experimental study on spinal fusion induced by hBMP-4 gene modified tissue engineered bone].

OBJECTIVE: To evaluate the efficacy of hBMP-4 gene modified tissue engineered bone graft in the enhancement of rabbit spinal fusion and find an ideal kind of substitute for the autograft bone. METHODS: Rabbit BMSCs were cultured and transfected with AAV-hBMP-4 using different MOI value. The optimal MOI value were determined by observing cell's morphology change. BMSCs were then transfected with AAV-hBMP4 and AAV-EGFP respectively, following which the transfected cells were evenly suspended in a collagen sponge I, and implanted to either side of the L5,6 intertransverse spaces posterolateral in the New Zealand rabbits to induce spinal fusion. Fourteen rabbits were randomly divided into 2 groups. Group 1: AAV-hBMP-4 transfected BMSCs in the right side (hBMP-4 side) and autograft bone in the left side. Group 2: AAV-hBMP-4 transfected BMSCs in the right side (hBMP-4 side) and AAV-EGFP transfected BMSCs in the left side (EGFP side). Radiographs and three-dimensional CT of the spine, manual palpation, gross and histological examination of the fusion masses for all the animals were performed subsequent to animals having been sacrificed at 12 weeks after surgery. RESULTS: Evaluation has been taken in 12 New Zealand rabbits delivered into 2 groups which meet the criterion after operation. Eleven in 12 implemented sides involved hBMP-4 achieved bony fusion, to which 5 in 6 autografted sides was similar. But only 2 in 6 sides in EGFP-group achieved bony fusion meanwhile. Three-dimensional CT scan and palpation also evidenced the results. Bone formation was observed obviously on specimen both in hBMP4 sides and autografted ones. EGFP-group also got bony integration, but the quantity was small. CONCLUSION: Tissue-engineered bone graft constructed from application of hBMP4 is a fine substitute for autograft. Effective enhancement of bony integration in spinal fusion surgery has been evidenced in vivo.

[Biomechanical effect of the iliac screw insertion depth on lumbo-iliac fixation construct].

OBJECTIVE: To biomechanically compare the stability of the short and long iliac screw fixation constructs in lumbo-iliac reconstruction. METHODS: Seven adult human embalmed cadavers (L(3)-pelvis) were used. Using posterior spinal fixation system, L(4)-S(1) pedicle screw fixation was performed. This was defined as intact state of the sacroiliac joint. After the intact test, total sacrum resection and L(4)-L(5)-pelvis reconstruction by pedicle screw and iliac screw with different lengths were performed as follow: short screw group (as the length of exceeding 2 mm over ischial notch) and long screw group (as the length of exceeding 2 mm over anterior inferior iliac spine). Using the 858 MTS material testing machine, biomechanical testing was performed under 800 N compression and 7 Nm torsion loading modes. At last, the axial pullout test of two iliac screws was executed. Construct stiffness in compression and torsion test, and maximum pullout force were analyzed. RESULTS: Insertion lengths of the short and long iliac screw were (70 +/- 2) mm and (138 +/- 4) mm respectively. The lumbo-pelvic reconstruction using short and long iliac screw, respectively restored 53.3% +/- 13.6% and 57.6% +/- 16.2% of the initial stiffness in compression testing, and respectively harvested 55.1% +/- 11.9% and 62.5% +/- 9.2% of the initial stiffness in torsion testing. No significant difference was detected between the two reconstructions (P > 0.05), however, the compressive and torsional stiffness of the two techniques were markedly less than the intact condition (P < 0.05). The maximum pullout strength of long iliac screw was significantly higher than short screw (P < 0.05). CONCLUSIONS: Under the physical loading, lumbo-pelvic fixation construct using the short iliac screw may obtain mechanical stability comparable to that by long iliac screw. The short iliac screw is only the half of the long iliac screw by length, could reduce the implantation risk. However, the long iliac screw behaves greater axial pullout force, should be applied as far as possible in the osteoporosis patient. The lumbo-pelvic reconstruction utilizing any length of iliac screw is difficult to restore the local stability.

[Sub-endplate microcirculation disturbance directly contributes to intervertebral disc degeneration].

OBJECTIVE: To build sub-endplate microcirculation disturbance animal model and to investigate the potential pathogenesis of intervertebral disc degeneration (IVDD). METHODS: Twenty four New Zealand white rabbits were divided into treatment group (Group A) and control group (Group B). In Group A, animals received endotoxin and corticosteroid application to build sub-endplate microcirculation disturbance animal model, validated by microthrombus staining. In Group B, animals were given no drug, but standard feeding. After 3 month, the extent of IVDD was evaluated by the water content, biochemistry analysis, and morphology. RESULTS: Sub-endplate microthrombus staining confirmed the exist of microcirculation disturbance. The water content and biochemistry components content of disc in Group A were lower than those of disc in Group B, and IVDD was observed in morphology. CONCLUSION: Sub-endplate microcirculation disturbance can directly contribute to IVDD, the nutrients diffusion barrier is the potential pathogenesis of IVDD.

Increased survival of patients aged 0-29 years with osteosarcoma: A period analysis, 1984-2013.

PURPOSE: Osteosarcoma is the most common primary malignancy of bone, and typically occurs among children and adolescence. This study aims to evaluate treatment outcomes among children, adolescents and young adults with osteosarcoma over the three decades by the changes in the long-term relative survival. METHODS: Osteosarcoma incidence and relative survival data from Surveillance, Epidemiology, and End Results (SEER) registries during 1984-2013 were analyzed. The survival differences over three decades, age, sex, race, and socioeconomic status (SES) were assessed by comparing Kaplan-Meier curves. RESULTS: The overall incidence of osteosarcoma kept relatively stable with 0.4 per 100 000 in the three decades with the peak incidence occurring in the aged 10-19 group. The 10-year relative survival rate (RSR) increased from 57.7% to 61.0% in the three decades, with the greatest increase in the aged 0-9 group from 48.2% to 65.7%. The 10-year RSR improved from 54.1% to 61.5% in males, and from 62.4% to 63.0% in females, respectively, in the three decades. Furthermore, survival dramatically improved from 30% to 60% in the high-poverty group over the three decades. CONCLUSION: This study demonstrated that the overall incidence of osteosarcoma remained stable, with an improvement in survival in the three decades. The improved survival was greater in males than in females in the three decades. Furthermore, the survival significantly increased in high-poverty group, which was attributed to increasing improved health care system and patients with low finance can also have access to receiving effective and consistent treatment without distinction.

Inflammation Intensity-Dependent Expression of Osteoinductive Wnt Proteins Is Critical for Ectopic New Bone Formation in Ankylosing Spondylitis.

OBJECTIVE: To investigate the molecular mechanism underlying inflammation-related ectopic new bone formation in ankylosing spondylitis (AS). METHODS: Spinal tissues and sera were collected from patients with AS and healthy volunteers and examined for the expression of Wnt proteins. An in vitro cell culture system mimicking the local inflammatory microenvironment of bone-forming sites was established to study the relationship between inflammation and Wnt expression, the regulatory mechanism of inflammation-induced Wnt expression, and the role of Wnt signaling in new bone formation. Modified collagen-induced arthritis (CIA) and proteoglycan-induced spondylitis (PGIS) animal models were used to confirm the key findings in vivo. RESULTS: The levels of osteoinductive Wnt proteins were increased in sera and spinal ligament tissues from patients with AS. Constitutive low-intensity tumor necrosis factor (TNF) stimulation, but not short-term or high-intensity TNF stimulation, induced persistent expression of osteoinductive Wnt proteins and subsequent bone formation through NF-κB (p65) and JNK/activator protein 1 (c-Jun) signaling pathways. Furthermore, inhibition of either the Wnt/ß-catenin or Wnt/protein kinase Cδ (PKCδ) pathway significantly suppressed new bone formation. The increased expression of Wnt proteins was confirmed in both the modified CIA and PGIS models. A kyphotic and ankylosing phenotype of the spine was seen during long-term observation in the modified CIA model. Inhibition of either the Wnt/ß-catenin or Wnt/PKCδ signaling pathway significantly reduced the incidence and severity of this phenotype. CONCLUSION: Inflammation intensity-dependent expression of osteoinductive Wnt proteins is a key link between inflammation and ectopic new bone formation in AS. Activation of both the canonical Wnt/ß-catenin and noncanonical Wnt/PKCδ pathways is required for inflammation-induced new bone formation.

Epigenetic upregulation of CXCL12 expression contributes to the acquisition and maintenance of morphine-induced conditioned place preference.

Addiction and rewarding effect is a primary side effect of morphine, which is commonly used to relieve the acute or chronic pain. Several lines of evidence have suggested that inflammation response in the VTA contributes to morphine-induced reward (conditioned place preference, CPP), while the mechanism are poorly understood. The present study showed that repeated morphine conditioning persistently increased the expression of CXCL12 mRNA and protein in VTA. Furthermore, inhibition of CXCL12 prevented the acquisition and maintenance, but not the expression, of morphine-induced CPP in rodent. In addition, molecular analysis revealed that morphine conditioning increased the occupancy of p-STAT3 in the specific binding site (-1667/-1685) of CXCL12 promoter regions, and enhanced the interaction between acetyltransferase p300 and STAT3, and, hence, induced the histone H4 hyperacetylation in the promoter region and facilitated the transcription and expression of CXCL12 in VTA. Collectively, these results, for the first time, provided the evidence that persisted increase of VTA CXCL12 via epigenetic mechanism mediated the acquisition and maintenance, but not the expression, of morphine CPP.

[One-stage single balloon multiple expansions percutaneous kyphoplasty: report of 18 cases].

OBJECTIVE: To observe the effect and safety of one-stage single balloon multiple expansions percutaneous kyphoplasty (PKP) in treatment of osteoporotic vertebral compressive fracture (OVCF) and spinal tumor. METHODS: One-stage single balloon multiple expansions PKP was performed on 18 patients, 5 males and 13 females, aged 68.77 (44 - 80), with 45 vertebrae, including 11 case of OVCF (with 29 diseased vertebrae), 11 cases of multiple vertebral fracture (with 19 diseased vertebrae), 5 cases of multiple myeloma (with 12 diseased vertebrae), and 2 case of spinal metastatic tumor (with 4 diseased vertebrae), the vital signs were record during operation. Pain relief and functional recovery were evaluated with visual analogue pain scale (VAS) and Oswestry disability index (ODI) scaling, and restoration of vertebral height and Cobb angle were evaluated by X-ray examination. Follow-up was conducted by telephone survey or clinic consults for 12.3 months (6 - 18 months). RESULTS: Operation was successfully performed on all patients with an operative time of 29.3 min (55 - 127 min) per vertebra. The average pressure of the balloon expansion was 165 Psi (87 - 210 Psi), and the average balloon expanded volume was 3.25 ml (1.5 - 4 ml). A balloon was expanded 2 approximately 5 times in one operation with the average of 2.94 expanded times. The bone cement volume injected was 3.95 ml (2 - 8.5 ml) per vertebra. Epidural cement leakage was seen in 1 vertebra in 1 case and paraspinal leakage was seen in two vertebrae in 1 case. The VAS and ODI scoring of these patients were both decreased significantly after operation. Both the anterior height and midline height of vertebrae were significantly improved. The pain relief and functional recovery were substantial and maintained to the last follow-up without any re-collapse or adjacent level fracture. CONCLUSION: one-stage single balloon multiple expansions PKP is effective, economic and safe in treatment of multi-level OVCF and spinal tumor.