Critical contributions of protein cargos to the functions of macrophage-derived extracellular vesicles.

BACKGROUND: Macrophages are highly plastic innate immune cells that play key roles in host defense, tissue repair, and homeostasis maintenance. In response to divergent stimuli, macrophages rapidly alter their functions and manifest a wide polarization spectrum with two extremes: M1 or classical activation and M2 or alternative activation. Extracellular vesicles (EVs) secreted from differentially activated macrophages have been shown to have diverse functions, which are primarily attributed to their microRNA cargos. The role of protein cargos in these EVs remains largely unexplored. Therefore, in this study, we focused on the protein cargos in macrophage-derived EVs. RESULTS: Naïve murine bone marrow-derived macrophages were treated with lipopolysaccharide or interlukin-4 to induce M1 or M2 macrophages, respectively. The proteins of EVs and their parental macrophages were subjected to quantitative proteomics analyses, followed by bioinformatic analyses. The enriched proteins of M1-EVs were involved in proinflammatory pathways and those of M2-EVs were associated with immunomodulation and tissue remodeling. The signature proteins of EVs shared a limited subset of the proteins of their respective progenitor macrophages, but they covered many of the typical pathways and functions of their parental cells, suggesting their respective M1-like and M2-like phenotypes and functions. Experimental examination validated that protein cargos in M1- or M2-EVs induced M1 or M2 polarization, respectively. More importantly, proteins in M1-EVs promoted viability, proliferation, and activation of T lymphocytes, whereas proteins in M2-EVs potently protected the tight junction structure and barrier integrity of epithelial cells from disruption. Intravenous administration of M2-EVs in colitis mice led to their accumulation in the colon, alleviation of colonic inflammation, promotion of M2 macrophage polarization, and improvement of gut barrier functions. Protein cargos in M2-EVs played a key role in their protective function in colitis. CONCLUSION: This study has yielded a comprehensive unbiased dataset of protein cargos in macrophage-derived EVs, provided a systemic view of their potential functions, and highlighted the important engagement of protein cargos in the pathophysiological functions of these EVs.

Harmine loaded Au@MSNs@PEG@Asp6 nano-composites for treatment of spinal metastasis from lung adenocarcinoma by targeting ANXA9 in vivo experiment.

Background: Annexin A9 (ANXA9) has been proved to be concerned with cancer development. However, to explore the clinical consequences of ANXA9 in lung adenocarcinoma (LUAD), especially its correlation to spinal metastasis (SM) has no in-depth study. The study was expected to elucidate the mechanism of ANXA9 in regulating SM of LUAD and create a productive nano-composites delivery system targeting this gene for treatment of SM. Methods: Harmine (HM), a ß-carboline extracted from the traditional Chinese herb Peganum harmala, loaded Au@MSNs@PEG@Asp6 (NPS) nano-composites were synthesized. Bioinformatics analysis and clinical specimens' tests were used to verify the association between ANXA9 and prognosis of LUAD with SM. The immunohistochemistry (IHC) was employed to detect the expression levels of the ANXA9 protein in LUAD tissues with or without SM, and its significance in clinic was also explored. ANXA9­siRNA was applied to investigate the molecular mechanism of ANXA9 in tumor behaviors. The HM release kinetics was detected by high performance liquid chromatography (HPLC) method. The cellular uptake efficiency of nanoparticles by A549 cells was observed by fluorescence microscope. Antitumor effects of nanoparticles were assessed in the nude mouse model of SM. Results: The genomic amplification of ANXA9 was prevalent in LUAD tissues and closely associated with poor outcome and SM (P<0.01). The experimental result manifested that high expression of ANXA9 could lead to wretched prognosis and ANXA9 was an independent risk factor for survival (P<0.05). After impeding expression of ANXA9, the proliferation and metastatic ability of tumor cells obviously decreased, and expression of matrix metallopeptidase 2 (MMP-2) and matrix metallopeptidase 9 (MMP-9) were considerably downregulated, while the expression of associated oncogene pathway were downregulated (P<0.01) as well. The synthesized HM-loaded NPS nano-composites could target to cancer and response to reactive oxygen species (ROS) to release HM slowly. Notably, in comparison to free HM, the nano-composites showed excellent targeting and anti-tumor effects in the A549 cell-bearing mouse model. Conclusions: ANXA9 may serve as a novel biomarker for predicting poor prognosis in LUAD, and we provided an efficient and targeting drug delivery nano-composites system for precise treatment of SM from LUAD.

Multifunctional Janus Nanoplatform for Efficiently Synergistic Theranostics of Rheumatoid Arthritis.

Progress has been made in the application of nanomedicine in rheumatoid arthritis (RA) treatment. However, the whole process of monitoring and treatment of RA remains a formidable challenge due to the complexity of the chronic autoimmune disease. In this study, we develop a Janus nanoplatform (denoted as Janus-CPS) composed of CeO2-Pt nanozyme subunit on one side and periodic mesoporous organosilica (PMO) subunit on another side for simultaneous early diagnosis and synergistic therapy of RA. The Janus nanostructure, which enables more active sites to be exposed, enhances the reactive oxygen species scavenging capability of CeO2-Pt nanozyme subunit as compared to their core-shell counterpart. Furthermore, micheliolide (MCL), an extracted compound from natural plants with anti-osteoclastogenesis effects, is loaded into the mesopores of PMO subunit to synergize with the anti-inflammation effect of nanozymes for efficient RA treatment, which has been demonstrated by in vitro cellular experiments and in vivo collagen-induced arthritis (CIA) model. In addition, by taking advantage of the second near-infrared window (NIR-II) fluorescent imaging, indocyanine green (ICG)-loaded Janus-CPS exhibits desirable effectiveness in detecting RA lesions at a very early stage. It is anticipated that such a Janus nanoplatform may offer an alternative strategy of functional integration for versatile theranostics.

Scutellarin-mediated autophagy activates exosome release of rat nucleus pulposus cells by positively regulating Rab8a via the PI3K/PTEN/Akt pathway.

To provide a basis for promising exosome-based therapies against intervertebral disc degeneration (IDD), our present research aimed to identify a mechanism underlying the vesicle release from nucleus pulposus cells (NPCs). Scutellarin (SC) is a natural chemotherapeutic agent isolated from Erigeron breviscapus with a variety of biological activities. Here, we observed the significantly elevated autophagy levels in rat NPCs under the stimulation of SC, leading to a concomitant enhancement of intracellular vesicle release, which could be attributed to the inactivation of the phosphoinositide 3-kinase (PI3K)/phosphatase and tensin homolog (PTEN)/protein kinase B (Akt) pathway. To ensure that exosome release was driven by SC via the autophagic pathway, we implemented gain-of-function and loss-of-function studies by additionally using insulin-like growth factor-1 (IGF-1) and small-interfering RNA of autophagy-related gene 5 (ATG5), and the exosome secretion decreased in the case of attenuated autophagy. Evidently, the treatment with SC exerted the remarkable upregulation of Rab8a through the overexpression of ATG5. After the respective knockdown of ATG5 and Rab8a, the increased release of exosomes induced by SC was reversed, whereas the number of intracellular vesicles was restored. Overall, it can be concluded that SC contributes to the autophagy activation in NPCs by acting on the PI3K/PTEN/Akt pathway, which upregulates the expression of Rab8a and promotes the release of exosomes, inspiring novel therapeutic strategies in preventing IDD that might be fruitfully investigated.

Excessive mechanical strain accelerates intervertebral disc degeneration by disrupting intrinsic circadian rhythm.

Night shift workers with disordered rhythmic mechanical loading are more prone to intervertebral disc degeneration (IDD). Our results showed that circadian rhythm (CR) was dampened in degenerated and aged NP cells. Long-term environmental CR disruption promoted IDD in rats. Excessive mechanical strain disrupted the CR and inhibited the expression of core clock proteins. The inhibitory effect of mechanical loading on the expression of extracellular matrix genes could be reversed by BMAL1 overexpression in NP cells. The Rho/ROCK pathway was demonstrated to mediate the effect of mechanical stimulation on CR. Prolonged mechanical loading for 12 months affected intrinsic CR genes and induced IDD in a model of upright posture in a normal environment. Unexpectedly, mechanical loading further accelerated the IDD in an Light-Dark (LD) cycle-disrupted environment. These results indicated that intrinsic CR disruption might be a mechanism involved in overloading-induced IDD and a potential drug target for night shift workers.

TNF-α-stimulated nucleus pulposus cells induce cell apoptosis through the release of exosomal miR-16 targeting IGF-1 and IGF-1R in rats.

BACKGROUND: Exosomes may contain excess cellular components released by cells in response to harmful external stimuli to maintain cellular homeostasis. Inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-α), can induce cell apoptosis, alter cellular component expression levels, and stimulate exosome release. In this study, we examined whether exosomes released from nucleus pulposus cells (NPCs) under inflammatory conditions could induce normal NP cell apoptosis in rats and its underlining mechanism. METHODS: Exosomes were isolated from TNF-α-treated NPCs and used to treat normal NPCs. The effects were assessed by flow cytometry and western blot analysis. Anti-apoptotic insulin-like growth factor-1 (IGF-1) expression in NPCs was assessed by western blot analysis. Given the exosomal miRNAs might be the key factors of exosomes, bioinformatics approaches and quantitative real-time polymerase chain reaction (qRT-PCR) were used to identify IGF-1-regulating micro RNAs (miRNAs), including miR-16. Luciferase reporter assay assessed miR-16 regulation of IGF-1 and IGF-1 receptor (IGF-1R). NPCs were transfected with miR-16 mimic, and exosomes were applied to normal NPCs. NPCs were pretreated with 10 ng/mL TNF-α, transfected with miR-16 inhibitors, and the exosomes were isolated. Cell and exosome miR-16 levels were detected by qRT-PCR. Western blot analysis determined IGF-1, IGF-1R, and apoptotic marker levels in exosome-treated NPCs. RESULTS: Exosomes from TNF-α-treated NPCs induced apoptosis in normal NPCs and repressed IGF-1 expression. Exosomal miR-16 regulated IGF-1 and induced NPC apoptosis. The dual-luciferase reporter assay revealed that miR-16 binds the 3' untranslated regions (3'-UTRs) of IGF-1 and IGF-1R. Exosomal miR-16 repressed IGF-1 and the IGF-1R/phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) pathway which therefore induced NPC apoptosis. Rescue experiments using miR-16 inhibitors further validated these findings. CONCLUSIONS: The inflammatory factor TNF-α stimulated exosome release from NPCs, which induced the apoptosis of normal NPCs through the actions of exosomal miR-16. Exosomal miR-16 directly repressed the anti-apoptotic IGF-1/IGF-1R pathway, increasing the apoptosis of NPCs.

Peptide vaccine-conjugated mesoporous carriers synergize with immunogenic cell death and PD-L1 blockade for amplified immunotherapy of metastatic spinal.

The clinical treatment of metastatic spinal tumor remains a huge challenge owing to the intrinsic limitations of the existing methods. Programmed cell death protein 1 (PD1)/programmed cell death ligand 1 (PD-L1) pathway blockade has been explored as a promising immunotherapeutic strategy; however, their inhibition has a low response rate, leading to the minimal cytotoxic T cell infiltration. To ameliorate the immunosuppressive microenvironment of intractable tumor and further boost the efficacy of immunotherapy, we report an all-round mesoporous nanocarrier composed of an upconverting nanoparticle core and a large-pore mesoporous silica shell (UCMS) that is simultaneously loaded with photosensitizer molecules, the IDO-derived peptide vaccine AL-9, and PD-L1 inhibitor. The IDO-derived peptide can be recognized by the dendritic cells and presented to CD8+ cytotoxic T cells, thereby enhancing the immune response and promoting the killing of the IDO-expressed tumor cells. Meanwhile, the near-infrared (NIR) activated photodynamic therapy (PDT) could induce immunogenic cell death (ICD), which promotes the effector T-cell infiltration. By combining the PDT-elicited ICD, peptide vaccine and immune checkpoint blockade, the designed UCMS@Pep-aPDL1 successfully potentiated local and systemic antitumor immunity and reduced the progression of metastatic foci, demonstrating a synergistic strategy for cancer immunotherapy.

Rationally integrating peptide-induced targeting and multimodal therapies in a dual-shell theranostic platform for orthotopic metastatic spinal tumors.

Metastatic tumors present great challenges in diagnosis and treatment. Herein, a proof-of-concept theranostic nanoplatform composed of an Au nanoparticle core and a double-shell of metal-organic framework (MOF) and mesoporous silica (MS) is developed for combating spinal metastasis of lung cancer in an orthotopic model. Two drugs, Alpelisib (BYL719) as an inhibitor and cisplatin as a chemotherapeutic drug, are separately loaded into the double-shell with high loading content. A targeting peptide called dYNH and indocyanine green (ICG) are conjugated onto the outmost MS layer for specifically targeting metastatic tumor cells and enhancing photothermal effect. The resultant Au@MOF@MS-ICG -dYNH-PAA (AMMD) shows enhanced cellular uptake on tumor cells and accumulation at metastatic spinal tumors, as evidenced by fluorescent and photoacoustic imaging. Benefiting from this ultra-high affinity to tumor cells and the photothermal effect of ICG, the dual-drug-loaded AMMD (BCAMMD) modified with ICG exhibits superior therapeutic efficacy on spinal tumors. More importantly, bone destruction, which frequently occurs in bone-related tumors, is effectively suppressed by BYL719 in BCAMMD. Hence, by rationally integrating multiple functions, including excellent targeting ability, dual-drug loading, photothermal therapy, and photoacoustic imaging, the developed all-in-one theranostic nanoplatform provides a useful paradigm of employing nanomedicine to treat metastatic spinal tumors efficiently.

Decorin inhibits nucleus pulposus apoptosis by matrix-induced autophagy via the mTOR pathway.

Decorin (Dcn) is a member of the class I small leucine-rich proteoglycans, whose expression in the nucleus pulposus (NP) of intervertebral discs (IVDs) has been shown to increase with aging in humans and sheep. Dcn induces autophagy in endothelial cells; however, its precise role in NP and IVD degeneration during aging is not well understood. We addressed this question in the present study by treating rat nucleus pulposus cells (NPCs) with different concentrations of Dcn. The Western blot analysis and terminal deoxynucleotidyl transferase dUTP nick end labeling assay results showed that Dcn treatment induced autophagy and decreased apoptosis caused by interleukin (IL)-1ß application. This effect was dependent on the protein kinase B/mechanistic target of rapamycin (mTOR)/p70 S6 kinase signaling. Dcn treatment also decreased the expression of matrix metalloproteinase-3 and -13 and decreased the IL-1ß-induced attenuation of collagen type II and aggrecan levels. The role of Dcn in stimulating autophagy was further supported by the fact that the observed effects were abrogated by knocking down autophagy-related protein 7 with Atg7 small interfering RNA. Thus, Dcn protects NPCs in IVDs from IL-1ß-induced apoptosis and degeneration by promoting autophagy through mTOR signaling.

Predict overall survival of spinal conventional chordoma: Development and assessment of a new predictive nomogram.

OBJECTIVE: To predict the 5-year overall survival (OS) rate in patients with conventional chordoma of the spine PATIENTS AND METHODS: The Surveillance, Epidemiology, and End Results (SEER) Registry was used to identify patients with conventional chordoma of the spine from 1994 to 2013. The entire cohort(n = 294) was randomly divided into training (n = 147) and validation (n = 147) cohorts to construct a nomogram. We used the univariate Log-rank test and multivariate Cox model to examine the independent prognostic factors associated with OS. These prognostic factors were integrated to construct a nomogram through R studio. The predictive and validating capacity of the nomogram was calculated by Harrell's concordance index (C-index) and calibration curves. RESULTS: A total of 294 patients were identified with conventional chordoma of the spine. The patients' age at diagnosis, tumor size, EOD (extent of disease), and treatment were independent prognostic factors and associated with OS. These prognostic factors were incorporated to construct a nomogram. The concordance index for the nomogram was 0.771 and 0.732 in the training cohort and validation cohort, respectively. Internal and external calibration curves for 5-year OS showed excellent matching between nomogram prediction and observed outcomes. CONCLUSIONS: The findings of this study provide population-based estimates of patients with conventional chordoma of the spine. Using this nomogram, surgeons can classify patients into different risk groups and achieve individualized treatment.

Hsa_circ_0006571 promotes spinal metastasis through sponging microRNA-138 to regulate sirtuin 1 expression in lung adenocarcinoma.

BACKGROUND: Circular RNAs (circRNAs) are known to participate in lung cancer. However, their role in spinal metastasis (SM) of lung adenocarcinoma remains elusive. In this study, we determined that hsa_circ_0006571 serves as a sponge for miR-138, which targets sirtuin 1 (Sirt1) in the development of SM. METHODS: A human circRNA microarray was performed to compare SM and lung adenocarcinoma samples. The expression of hsa_circ_0006571 and miR-138 was determined using quantitative polymerase chain reaction (qPCR) in vitro and in vivo. Cell proliferation was performed by Cell Counting Kit-8 (CCK-8) and apoptosis was analyzed by Annexin V/PI staining. RNA-pulldown and RNA immunoprecipitation (RIP) were used to analyze the interaction between hsa_circ_0006571. Tumor metastasis was determined through a xenograft experiment in vivo. RESULTS: Hsa_circ_0006571 was observed to be significantly upregulated in SM tissues through circRNA microarray and qPCR. We detected a lower expression of miR-138 in SM tissues compared with lung adenocarcinoma. Hsa_circ_0006571 silencing suppressed lung cancer cell proliferation and migration while promoting apoptosis. Hsa_circ_0006571 interacted with miR-138 to promote expression of Sirt1, leading to activation of epithelial-mesenchymal transition (EMT). Xenograft experiments showed that downregulation of hsa_circ_0006571 delayed the SM of lung adenocarcinoma cells via the miR-138-Sirt1 axis. CONCLUSIONS: Hsa_circ_0006571 promoted tumor cell migration and invasion via the miR-138/Sirt1 pathway. Our observations indicate that circRNAs are possible novel therapeutic targets for SM of lung adenocarcinoma.

Bioabsorbable self-retaining PLA/nano-sized ß-TCP cervical spine interbody fusion cage in goat models: an in vivo study.

STUDY DESIGN: This is an experimental animal study. OBJECTIVE: The objective of this study was to compare an anterior cervical discectomy and interbody fusion of a novel polylactide/nano-sized ß-tricalcium phosphate (PLA/nß-TCP) bioabsorbable self-retaining cervical fusion cage (BCFC) with an autologous bone graft and polyetheretherketone (PEEK) cages. BACKGROUND: Although PLA cervical cages have potential advantages compared with traditional materials, they are not currently routinely used in spine surgery because of undesirable effects such as the lack of osteoconductivity and osteolysis around the implant. This study involved the manufacturing of a bioabsorbable cage from PLA/nß-TCP that was then used as a device for anterior cervical discectomy and fusion (ACDF) on a goat cervical spine fusion model. MATERIALS AND METHODS: Eighteen goats underwent C3/C4 discectomy and were randomly divided into three groups based on the following methods: Group A (n=6), an autologous bone graft; Group B (n=6), PEEK cage filled with an autologous graft; and Group C (n=6), BCFC filled with an autologous iliac bone. Radiography was performed preoperatively and postoperatively and at 1, 4, 8, and 12 weeks after the operation. Disc space height (DSH) was measured at the same time. After 12 weeks, the fused segments were harvested and evaluated with functional radiographic views, biomechanical testing, and histological analyses. RESULTS: Over a 12-week period, the BCFC and PEEK cage groups exhibited significantly higher DSH values than the bone graft group. Additionally, the BCFC group yielded a significantly lower range of motion in axial rotation than both the autologous bone graft and PEEK cage groups. A histologic evaluation revealed an increased intervertebral bone volume/total volume ratio and better interbody fusion in the BCFC group than in the other groups. CONCLUSION: The BCFC device exhibited better results than the autologous bone graft and PEEK cages in single-level ACDF models in vivo. This device may be a potential alternative to the current PEEK cages.

Degenerative Spondylolisthesis in the Fifth Lumbar Vertebra and Radiographic Parameters: A Correlation Analysis.

STUDY DESIGN: A retrospective study. OBJECTIVE: This study aimed to analyze the relationships between degenerative spondylolisthesis in the fifth lumbar vertebra (L5-DS) and radiographic parameters and to further determine the radiographic predictors of the development of L5-DS. SUMMARY OF BACKGROUND DATA: Degenerative lumbar spondylolisthesis (DLS) is a common degenerative disease of the spine; however, the correlations between L5-DS and radiographic parameters remain controversial. PATIENTS AND METHODS: This retrospective case-control study was conducted in our hospital. Between 2011 and 2014, a total of 84 subjects with L5-DS were enrolled in the DLS group, and 56 healthy volunteers were recruited to the control group. A series of radiographic parameters, including the bone mineral density, disk degenerative index, disk height, L5 vertebral size (L5-VS), lumbar lordosis angle (LL), sacral slope angle (SS), pelvic incidence (PI), facet joint angulations (FJA) of the cephalad and caudad portions, and asymmetry of the FJA, were measured in both groups by 3 examiners. RESULTS: The bone mineral density, disk degenerative index, disk height, L5-VS, LL, SS, PI, and FJA exhibited significant differences (P=0.014-0.045) between the DLS and control groups. Significant changes in the FJA of the cephalad and caudad portions in the L4-L5 and L5-S1 segments were observed between the 2 groups (P=0.00, 0.00), whereas no significant differences in the asymmetries of FJA were observed in the L4-L5 or L5-S1 segments (P=0.605-0.972). Among all of the parameters, the L5-VS (P=0.025), SS (P=0.020), LL (P=0.031), PI (P=0.014), and FJA (P=0.022) were identified as being associated with the DLS group by multiple logistic regression analysis. CONCLUSIONS: In this study, SS, LL, PI, and a more sagittal FJA were proven to be risk factors for L5-DS, whereas L5-VS was found to be a likely protective factor against L5-DS. These parameters should be considered predictors of L5-DS.

Polypyrrole coating on poly-(lactide/glycolide)-ß-tricalcium phosphate screws enhances new bone formation in rabbits.

Polypyrrole (PPy) has gained interest as an implant material due to its multifunctional properties and its high compatibility with several cell and tissue types. For the first time, the biocompatibility and osteointegration of PPy coating, incorporated with chondroitin sulfate (CS), were studied in vivo by implanting PPy-coated bioabsorbable bone fixation composite screws of poly-(lactide/glycolide) copolymer (PLGA) and ß-tricalcium phosphate (TCP) into New Zealand white rabbits. Uncoated bioabsorbable polymer composite screws and commercially available stainless steel cortical screws were used as reference implants. The rabbits were euthanized 12 and 26 weeks after the implantation. The systemic effects were evaluated from food and water consumption, body weight, body temperature, clinical signs, blood samples, internal organ weights, and histological examination. Local effects were studied from bone tissue and surrounding soft tissue histology. New bone formation was evaluated by micro-computed tomography, tetracycline labeling and torsion tests. Torsion tests were performed in order to capture the peak value of the torsion force during the course of the screw's loosening. The coated screws induced significantly more bone formation than the uncoated screws. In addition, none of the implants induced any systemic or local toxicity. The results suggest that PPy is biocompatible with bone tissue and is a potential coating for enhancing osteointegration in orthopedic implants.

Minimum 5 year follow-up of multi-segmental lumbar degenerative disease treated with discectomy and the Wallis interspinous device.

We evaluate the clinical effects and radiological findings of the Wallis interspinous device (Zimmer, Warsaw, IN, USA) for the treatment of multi-segmental lumbar degenerative disease after a minimum 5 year follow-up period. A total of 26 adult patients underwent a primary discectomy followed by fixation of the segment with the Wallis interspinous device between December 2007 and August 2008. Twelve men and 14 women with an age range of 43 to 56 years (average: 47.6) were included. The visual analogue scale (VAS) for low back and leg pain, Oswestry Disability Index (ODI), foraminal height (FH), anterior disc height (aDH) and posterior disc height (pDH), range of motion (ROM) and Pfirrmann grades were obtained and compared before and after surgery. The VAS and ODI significantly decreased postoperatively (p < 0.05). The postoperative FH and pDH values increased significantly compared with the preoperative levels (p < 0.01) and the increase in the FH and pDH values remained statistically significant during the follow-up period. There were no statistically significant changes in the aDH values before and after surgery (p > 0.05). Also, there were no statistically significant changes in the ROM and Pfirrmann grade at the instrumented level and at the cephalad-adjacent segment (p>0.05). In our study, no patient underwent further surgery because of a re-prolapse or progression of index level degeneration or adjacent segment disease. The Wallis interspinous device was a useful alternative for treating multi-segmental lumbar degenerative disease and it offered a significant minimum 5 year symptom control.

Establishment of intervertebral disc degeneration model induced by ischemic sub-endplate in rat tail.

BACKGROUND CONTEXT: Microcirculatory dysfunction of the sub-endplate is considered to reduce nutrient supply to the intervertebral disc (IVD); however, direct interruption or destruction of blood vessels in the bone marrow of the vertebrae body adjacent to the endplate has not yet been described, especially with regard to the calcification and ossification of the cartilaginous endplate occurring during IVD degeneration. PURPOSE: The purpose of the study was to evaluate the causal relationship between IVD degeneration and blocking of the main blood supply gateway through the endplate. STUDY DESIGN/SETTING: The study describes a new IVD degeneration model induced by ischemic sub-endplate. PATIENT SAMPLE: A total of 40 Sprague-Dawley rats were included in the study group. OUTCOME MEASURES: To assess disc height, a radiograph was taken each month for 4 months. Changes in endplate, nucleus pulposus (NP), and annulus fibrosus (AF) were evaluated by histochemical and immunohistochemical staining to detect IVD degeneration. METHODS: Injection of 30 µL absolute ethanol into the IVD of rat tail at Co7/Co8 was used to induce injury. Controls were injected with 30 µL of phosphate-buffered saline into the IVD at Co8/Co9. RESULTS: In the ethanol-injected group, disc height gradually decreased and bone sclerosis developed in the endplate. In the NP, cell transformation occurred, changing from predominantly vacuolar cells to chondrogenic cells and eventually fibrocartilaginous cells, along with fibrosis of the NP. As degeneration progressed, the AF developed disordered morphology and rough lamellae, and eventually ruptures and fibrosis. The extent of degeneration increased gradually over time, while the wavy tidemark of the growth plate regressed, and eventually disappeared. Initially positive collagen type II staining gradually decreased on the ischemic side of the sub-endplate. Except at the 3-month time point, expression of collagen type II, aggrecan, and Sox-9 in NP decreased gradually as degeneration progressed, compared with the control group. CONCLUSIONS: This model successfully reproduced IVD degeneration, which could be used for etiological studies on IVD degeneration and investigation of nutrient supply disturbance, and may provide a theoretical foundation for clinical intervention and therapy for IVD degeneration in the future.

Effect of porosities of bilayered porous scaffolds on spontaneous osteochondral repair in cartilage tissue engineering.

Poly(lactide-co-glycolide)-bilayered scaffolds with the same porosity or different ones on the two layers were fabricated, and the porosity effect on in vivo repairing of the osteochondral defect was examined in a comparative way for the first time. The constructs of scaffolds and bone marrow-derived mesenchymal stem cells were implanted into pre-created osteochondral defects in the femoral condyle of New Zealand white rabbits. After 12 weeks, all experimental groups exhibited good cartilage repairing according to macroscopic appearance, cross-section view, haematoxylin and eosin staining, toluidine blue staining, immunohistochemical staining and real-time polymerase chain reaction of characteristic genes. The group of 92% porosity in the cartilage layer and 77% porosity in the bone layer resulted in the best efficacy, which was understood by more biomechanical mimicking of the natural cartilage and subchondral bone. This study illustrates unambiguously that cartilage tissue engineering allows for a wide range of scaffold porosity, yet some porosity group is optimal. It is also revealed that the biomechanical matching with the natural composite tissue should be taken into consideration in the design of practical biomaterials, which is especially important for porosities of a multi-compartment scaffold concerning connected tissues.

Recurrent adamantinoma in the thoracolumbar spine successfully treated by three-level total en bloc spondylectomy by a single posterior approach.

PURPOSE: Adamantinoma is a low-grade primary malignant bone tumour with slow growth and local recurrence. Its occurrence in the spine is extremely rare, particularly with multilevel involvement. This paper wants to present the first case involving a patient with recurrent thoracolumbar spinal adamantinoma, who underwent a successful three-level spondylectomy for en bloc resection. METHODS: A 24-year-old man with osteolytic masses of T11 and T12 vertebral bodies was performed curettage by a posterior approach in 2008. The pathology report showed the excised neoplasm was a rare adamantinoma. This patient underwent a tumorectomy again because of its local recurrence nearly 3 years later. In 2012, it was unfortunately revealed that the excised tumour had relapsed and had spread to the L1 vertebral body. Due to its repeated recurrence and aggressive lesion, total en bloc spondylectomy (TES) for this malignant tumour was thought to be the best option for preventing repeated recurrence and possible cure. TES for T11-L1 thoracolumbar spine was performed and spinal reconstruction was completed with instrumentation and a titanium mesh cage through a one-stage single posterior approach. RESULTS: After three-level TES, neurological deficits of the patient demonstrated good recovery and no evidence of adamantinoma recurrence or deformity was found at 2-year follow-up. CONCLUSIONS: This is the first case involving multilevel thoracolumbar spinal adamantinoma with repeated recurrence to be successfully treated by three-level TES by a single posterior approach.

Molecular actions of ovarian cancer G protein-coupled receptor 1 caused by extracellular acidification in bone.

Extracellular acidification occurs under physiologic and pathologic conditions, such as exercise, ischemia, and inflammation. It has been shown that acidosis has various adverse effects on bone. In recent years there has been increasing evidence which indicates that ovarian cancer G protein-coupled receptor 1 (OGR1) is a pH-sensing receptor and mediates a variety of extracellular acidification-induced actions on bone cells and other cell types. Recent studies have shown that OGR1 is involved in the regulation of osteoclast differentiation, survival, and function, as well as osteoblast differentiation and bone formation. Moreover, OGR1 also regulates acid-induced apoptosis of endplate chondrocytes in intervertebral discs. These observations demonstrate the importance of OGR1 in skeletal development and metabolism. Here, we provide an overview of OGR1 regulation ofosteoclasts, osteoblasts, and chondrocytes, and the molecular actions of OGR1 induced by extracellular acidification in the maintenance of bone health.