Language：English   Publishing type：Research paper (scientific journal)  

INTRODUCTION: The purpose of this study was to assess the direct injection of bone marrow-derived mesenchymal stem cells (BMSCs) suspended in hyaluronic acid (HA) combined with drilling as a treatment for chondral defects in a canine model. METHODS: Tibial bone marrow was aspirated, and BMSCs were isolated and cultured. One 8.0-mm diameter chondral defect was created in the femoral groove, and nine 0.9-mm diameter holes were drilled into the defect. BMSCs (2.14 × 107 cells) suspended in HA were injected into the defect. HA alone was injected into a similar defect on the contralateral knee as a control. Animals were sacrificed at 3 and 6 months. RESULTS: Although the percentage of coverage assessed macroscopically was significantly better at 6 months than at 3 months in both the BMSC (p = 0.02) and control (p = 0.001) groups, there were no significant differences in the International Cartilage Repair Society grades. The Wakitani histological score was significantly better at 6 months than at 3 months in the BMSC and control groups. While the control defects were mostly filled with fibrocartilage, several of the defects in the BMSC group contained hyaline-like cartilage. The mean Wakitani scores of the BMSC group improved from 7.0 ± 1.0 at 3 months to 4.6 ± 0.9 at 6 months, and those of the control group improved from 9.4 ± 1.2 to 6.0 ± 0.6. The BMSC group showed significantly better regeneration than the control group at 3 months (p = 0.04), but the difference at 6 months was not significant (p = 0.06). CONCLUSIONS: The direct injection of BMSCs in HA combined with drilling enhanced cartilage regeneration.

DOI： 10.1016/j.reth.2015.10.003

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Language：Japanese   Publisher：(株)メジカルビュー社  

J-GLOBAL

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：SAGE PUBLICATIONS INC  

Objective. The objective of this study was to assess the effect of granulocyte colony-stimulating factor (G-CSF) on osteochondral defect repair in the rat knee. Design. Twenty-six 12-week-old male Lewis rats were randomly divided into 2 groups. From day 0 to day 4, the G-CSF group received glycosylated G-CSF, and the control group received phosphate-buffered saline. A 1.5-mm diameter and 1.0-mm deep osteochondral defect was introduced in the patellar groove of the bilateral femur in all rats on day 4. The peripheral blood nucleated cells were counted for 14 days from the first day of injection, the appearance of the cartilage repair was observed histologically and macroscopically for 2, 4, 8, 12, and 24 weeks after surgery. Results. The number of peripheral blood leukocytes increased 3 days and returned to normal levels 7 days after the first injection. Compared with the control group, the G-CSF group had more fibrous and/or bony tissue at earlier points in time. The tissue repair rate, which is defined as the percentage of repaired osteochondral defects, was significantly higher in the G-CSF group 4 weeks after surgery. However, there were no significant differences in the cartilage repair rate and the modified Wakitani score between the 2 groups at each time point. Conclusions. The defect filling was significantly better in the G-CSF group in the early phases. Our findings suggest that G-CSF may promote the repair of osteochondral defects by mediating an increase in the number of peripheral blood nucleated cells.

DOI： 10.1177/1947603514520628

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Language：English   Publisher：WILEY-BLACKWELL  

Web of Science

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：WILEY-LISS  

The periodontal ligament (PDL), a connective tissue located between the cementum of teeth and the alveolar bone of mandibula, plays a crucial role in the maintenance and regeneration of periodontal tissues. The PDL contains fibroblastic cells of a heterogeneous cell population, from which we have established several cell lines previously. To analyze characteristics unique for PDL at a molecular level, we performed cDNA microarray analysis of the PDL cells versus MC3T3-E1 osteoblastic cells. The analysis followed by validation by reverse transcription-polymerase chain reaction and immunochemical staining revealed that endoglin, which had been shown to associate with transforming growth factor (TGF)-beta and bone morphogenetic proteins (BMPs) as signaling modulators, was abundantly expressed in PDL cells but absent in osteoblastic cells. The knockdown of endoglin greatly suppressed the BMP-2-induced osteoblastic differentiation of PDL cells and subsequent mineralization. Interestingly, the endoglin knockdown did not alter the level of Smad-1/5/8 phosphorylation induced by BMP-2, while it suppressed the BMP-2-induced expression of IdI, a representative BMP-responsive gene. Therefore, it is conceivable that endoglin regulates the expression of BMP-2-responsive genes in PDL cells at some site downstream of Smad-1/5/8 phosphorylation. Alternatively, we found that Smad-2 as well as Smad-1/5/8 was phosphorylated by BMP-2 in the PDL cells, and that the BMP-2-induced Smad-2 phosphorylation was suppressed by the endoglin knockdown. These results, taken together, raise a possibility that PDL cells respond to BMP2 via a unique signaling pathway dependent on endoglin, which is involved in the osteoblastic differentiation and mineralization of the cells. J. Cell. Physiol. 222: 465-473, 2010. (C) 2009 Wiley-Liss, Inc.

DOI： 10.1002/jcp.21968

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：COMPANY OF BIOLOGISTS LTD  

We recently reported that tensile stress induces osteoblast differentiation and osteogenesis in the mouse calvarial suture in vitro. Using this experimental system, we identified PIASx beta, a splice isoform of Pias2, as one of the genes most highly upregulated by tensile stress. Further study using cell culture revealed that this upregulation was transient and was accompanied by upregulation of other differentiation markers, including osterix, whereas expression of Runx2 was unaffected. Runx2 and osterix are the two master proteins controlling osteoblast differentiation, with Runx2 being upstream of osterix. Targeted knockdown of PIASx beta by small interfering RNA (siRNA) markedly suppressed osteoblastic differentiation and matrix mineralization, whereas transient overexpression of PIASx beta caused the exact opposite effects. Regardless of PIASx beta expression level, Runx2 expression remained constant. Reporter assays demonstrated that osterix enhanced its own promoter activity, which was further stimulated by PIASx beta but not by its sumoylation-defective mutant. NFATc1 and NFATc3 additionally increased osterix transcriptional activity when co-transfected with PIASx beta. Because osterix has no consensus motif for sumoylation, other proteins are probably involved in the PIASx beta-mediated activation and NFAT proteins may be among such targets. This study provides the first line of evidence that PIASx beta is indispensable for osteoblast differentiation and matrix mineralization, and that this signaling molecule is located between Runx2 and osterix.

DOI： 10.1242/jcs.005090

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The aim of the study was to examine the chronological histology of osteoinduction of highly purified beta-tricalcium phosphate (beta-TCP) implanted in dog dorsal muscles. Specimens were harvested on days 14, 28, 42, 56, 112 and 168 after implantation, and were analyzed by hematoxylin and eosin (HE) staining, tartrate-resistant acid phosphatase (TRAP) staining, immunohistochemistry, in situ hybridization, and silver impregnation. After day 28, abundant TRAP- and cathepsin K-positive multinucleated cells adhered to beta-TCP, suggesting that these cells are osteoclasts that can resorb beta-TCP. On day 56, new bone was formed and alpha1 chain of type I procollagen mRNA-positive osteoblasts lined the newly formed bone. Silver impregnation showed abundant collagen fibrils within the beta-TCP micropores. These results suggest that micropores function as a storage space for extracellular matrix components, including collagen. Newly formed bone never degenerated in the late stage, suggesting that beta-TCP has good biocompatibility and this material retains the conditions appropriate for osteointegration and bioresorption. In conclusion, beta-TCP has osteoinductivity after implantation in dog dorsal muscles without use of bone marrow cells or osteoinductive cytokines. The appearance of a large number of active osteoclasts precedes new bone formation.

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Language：Japanese   Publisher：(一社)日本関節鏡・膝・スポーツ整形外科学会  

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Language：Japanese   Publisher：新潟整形外科研究会  

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