Polymeric meshes induce zonal regulation of matrix metalloproteinase-2 gene expression by macrophages and fibroblasts
ABSTRACT Matrix metalloproteinase-2 (MMP-2) is a key regulator in wound healing that orchestrates tissue remodeling. In the present study the spatial and temporal distribution of MMP-2 gene transcription, protein synthesis, and enzymatic activity were analyzed following polymeric mesh (polyglactin, polypropylene) implantation in transgenic reporter mice harboring MMP-2 regulatory sequences -1686/+423 or -1241/+423. Polymers induced MMP-2 promoter activity in macrophages within the foreign body granuloma via sequences -1686/+423 with concomitantly up-regulated protein synthesis and enzymatic activity. Macrophages distant from mesh filaments exhibited low MMP-2 expression levels. Fibroblasts surrounding mesh material displayed strong MMP-2 gene transcription independent of the included promoter sequences, whereas fibroblasts without close contact to mesh material had low MMP-2 synthesis rates due to silencing activity of sequences -1686/-1241. In vitro studies support a cellular crosstalk concept, as macrophages trans-repressed MMP-2 gene transcription in fibroblasts. The zonal and cell-specific regulation of MMP-2 gene transcription illuminates an intimate cellular crosstalk in foreign body reaction that may provide a new approach for mesh modification.
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ABSTRACT: Passive mode locking of the Yb:Sc2O3 laser is demonstrated. We investigate the laser performance with Ti:sapphire and diode-laser pumping. The laser is mode locked by use of a semiconductor saturable-absorber mirror and emits as much as 0.8 W of power in the picosecond range with a pump efficiency as high as 47%. With dispersion compensation, pulses as short as 230 fs for an average power of 0.54 W are obtained at 1044 nm. This is, to our knowledge, the first femtosecond oscillator based on an Yb-doped sesquioxide crystal.Optics Letters 03/2004; 29(4):391-3. DOI:10.1364/OL.29.000391 · 3.18 Impact Factor
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ABSTRACT: To identify changes over time in relative expression of matrix metalloproteinase-2 (MMP-2) and -9 (MMP-9) in synovial fluid from healthy calves and calves with experimentally induced septic arthritis. 12 Holstein calves. In 7 calves, Escherichia coli was injected in the right tarsal joint on day 1. Joint lavage was performed on day 2, and calves were treated with ceftiofur from days 2 through 21. Synovial fluid samples were collected on days 1 (before inoculation), 2 (before joint lavage), 3, 4, 8, 12, 16, 20, and 24. In the remaining 5 calves, joint lavage was performed on day 2 and synovial fluid samples were collected from the left tarsal joint. Relative expression of MMP-2 and MMP-9 was determined by means of gel zymography. On day 1, MMP-2 was detected in all synovial fluid samples but MMP-9 was not detected. In calves with septic arthritis, values for relative expression of MMP-9 monomer and dimer were significantly increased on days 2 through 20 and days 2 through 24, respectively, and relative expression of MMP-2 was significantly increased on days 3 through 20. There were significant linear associations between relative expression of the monomer and dimer forms of MMP-9 and between neutrophil count and relative expression of the MMP-9 monomer and dimer forms. Results indicated that relative expression of MMP-9 and MMP-2 increased in synovial fluid from calves with experimentally induced septic arthritis, with relative expression remaining high for several days after infection.American Journal of Veterinary Research 09/2008; 69(8):1022-8. DOI:10.2460/ajvr.69.8.1022 · 1.21 Impact Factor
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ABSTRACT: A resorbable copolymer of glycolide and L-lactide (PGLA), a terpolymer of glycolide, L-lactide, and epsilon-caprolactone (PGLCL), and a copolymer of glycolide and epsilon-caprolactone (PGCL) were synthesized by ring opening polymerization using zirconium acetylacetonate (Zr(acac)(4)) as an initiator. The structure and physicochemical surface properties of the materials were studied by NMR spectroscopy, gel permeation chromatography, differential scanning calorimetry, X-ray photoelectron spectroscopy, atomic force microscopy, and contact angle measurements. On the basis of contact angle measurements and the Owens-Wendt approach, the surface free energy was calculated. The effect of polymeric films produced by solvent casting on morphology and activity of L929 fibroblasts, and two types of macrophages (macrophages from peritoneal exudates and RAW 264.7 monocytes/macrophages), was analyzed. It was found that viability, adhesion, and morphology of fibroblasts on PGLA were very similar to control glass. On PGLCL more adhering cells were round, while on PGCL only single, poorly spread cells were seen, and their viability was significantly reduced. This may suggest that the interaction of fibroblasts with PGCL was due to its hydrophobicity and a very low polarity. Adhesion and viability of RAW 264.7 cells was significantly enhanced on PGLA but reduced on both PGLCL and PGCL. The increased synthesis/release of chemoattractants and metalloproteinases-2 and -9 was observed in the macrophages from peritoneal exudates cultured on PGLA and PGLCL. The viability of cells decreased in the following order: PGLA > PGLCL > PGCL. It is worth noting that glass transition temperature and susceptibility to mechanical deformation of the polymeric materials also decreased in the same order. It may imply that those physical parameters should be also considered as potential factors affecting cell behavior.Journal of Biomedical Materials Research Part A 11/2008; 87(2):524-35. DOI:10.1002/jbm.a.31802 · 3.37 Impact Factor