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In this study, dextran-coated polyvinyl formal (PVF) sponges with high water-holding capability were developed to increase the osteogenic response in the PVF sponge. The study aimed to estimate the effect of the increased water-holding capability of the sponges on osteogenic capacity at a bone defect site in the rabbit femur epiphysis. Bone formation was evaluated using radiography, microcomputed tomography (CT), and histological analysis at 2, 4, and 6 weeks after implantation. As shown by radiography and micro-CT findings, the dextran-coated PVF sponge without water-holding capability showed little bone formation at all evaluated time points. However, the dextran-coated PVF sponge with high water-holding capability showed increasing bone formation around the implant at 4 and 6 weeks after implantation. Furthermore, as shown by micro-CT quantitative analysis, the grafted PVF sponge with high water-holding capability showed significantly greater values for percentage of bone volume per total volume and mean bone mineral density compared with the grafted PVF sponge without water-holding capability at 4 and 6 weeks after implantation. These results suggest that the dextran-coated PVF sponge with high water-holding capability promoted osteogenesis in vivo. The PVF sponge might be a new biomaterial to be used as a fill material for bone defects. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 103B: 188-194, 2015. [ABSTRACT FROM AUTHOR]

The aim of the study is to estimate the effects of the water-holding capability of the polyvinyl formal (PVF) sponges on osteogenic response in vitro experiments. The rat bone marrow stem cells (BMCs) were seeded and cultured for up to 4 weeks under static conditions in osteogenic media to evaluate the adhesion, proliferation, differentiation, and mineralization on the Dextran-coated PVF sponges with or without water-holding capability. The BMCs seeded onto the PVF sponges with water-holding capability showed more significant increases in DNA content, alkaline phosphatase (ALP) activity, osteocalcin content, and calcium deposition than those without water-holding capability. These results suggest that the Dextran-coated PVF sponges with high water-holding capability would have potential uses as both a new scaffold to bone tissue engineering and as a new biomaterial. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 247-253, 2014. [ABSTRACT FROM AUTHOR]

Study Design: Experimental human study., Purpose: To determine whether angiopoietin-like protein 2 (ANGPTL2) is highly expressed in the hyperplastic facet joint (FJ) synovium and whether it activates interleukin-6 (IL-6) secretion in FJ synoviocytes., Overview of Literature: Mechanical stress-induced synovitis is partially, but significantly, responsible for degenerative and subsequently osteoarthritic changes in the FJ tissues in patients with lumbar spinal stenosis (LSS). However, the underlying molecular mechanism remains unclear. IL-6 is highly expressed in degenerative FJ synovial tissue and is responsible for local chronic inflammation. ANGPTL2, an inflammatory and mechanically induced mediator, promotes the expression of IL-6 in many cells., Methods: FJ tissues were harvested from five patients who had undergone lumbar surgery. Immunohistochemistry for ANGPTL2, IL-6, and cell markers was performed in the FJ tissue samples. After cultured synoviocytes from the FJ tissues were subjected to mechanical stress, ANGPTL2 expression and secretion were measured quantitatively using real-time quantitative reverse-transcription-polymerase chain reaction and enzyme-linked immunosorbent assay (ELISA), respectively. Following ANGPTL2 administration in the FJ synoviocytes, anti-nuclear factor-κB (NF-κB) activation was investigated using immunocytochemistry, and IL-6 expression and secretion were assayed quantitatively with or without NF-κB inhibitor. Moreover, we assessed whether ANGPTL2-induced IL-6 modulates leucocyte recruitment in the degenerative process by focusing on the monocyte chemoattractant protein-1 (MCP-1) expression., Results: ANGPTL2 and IL-6 were highly expressed in the hyperplastic FJ synovium samples. ANGPTL2 was co-expressed in both, fibroblast-like and macrophage-like synoviocytes. Further, the expression and secretion of ANGPTL2 in the FJ synoviocytes increased in response to stimulation by mechanical stretching. ANGPTL2 protein promoted the nuclear translocation of NF-κB and induced IL-6 expression and secretion in the FJ synoviocytes. This effect was reversed following treatment with NF-κB inhibitor. Furthermore, ANGPTL2-induced IL-6 upregulated the MCP-1 expression in the FJ synoviocytes., Conclusions: Mechanical stress-induced ANGPTL2 promotes chronic inflammation in the FJ synovium by activating IL-6 secretion, leading to FJ degeneration and subsequent LSS.

We have developed a new exchangeable gene trap vector, pU-17, carrying the intron-lox71-splicing acceptor (SA)-beta geo-loxP-pA-lox2272-pSP73-lox511. The SA contains three stop codons in-frame with the ATG of beta galactosidase/neomycin-resistance fusion gene (beta geo) that can function in promoter trapping. We found that the trap vector was highly selective for integrations in the introns adjacent to the exon containing the start codon. Furthermore, by using the Cre-mutant lox system, we successfully replaced the beta geo gene with the enhanced green fluorescent protein (EGFP) gene, established mouse lines with the replaced clones, removed the selection marker gene by mating with Flp-deleter mice, and confirmed that the replaced EGFP gene was expressed in the same pattern as the beta geo gene. Thus, using this pU-17 trap vector, we can initially carry out random mutagenesis, and then convert it to a gain-of-function mutation by replacing the beta geo gene with any gene of interest to be expressed under the control of the trapped promoter through Cre-mediated recombination.