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The behaviour of regenerated cellulose composites produced from rayon (Cordenka™), dissolved using either ionic liquids or sodium hydroxide (common cellulose solvent) was investigated to determine in vivo biocompatibility. Cellulose-dissolving ionic liquids (1-ethyl-3-methylimidazolium, 1-butyl-3-methylimidazolium, and four triaminocyclopropenium cation salts) and sodium hydroxide were examined in vitro using rat fibroblast-like cells to determine the most cytocompatible ionic liquid. The selected ionic liquid and sodium hydroxide were used to prepare regenerated cellulose constructs. The prepared cellulose constructs and ultra-high-molecular-weight polyethylene controls were implanted subcutaneously into adult male Sprague–Dawley rats. Post-surgery, implants were processed into a resin. Degradation properties were determined, and morphometric analysis was performed on resin sections stained with Haematoxylin & Eosin, Toluidine blue and Verhoeff's van Giessen. The implants presented excellent biocompatibility. However, the cellulose implants showed a rapid infiltration of several mature fibroblasts and collagen fibres. A steady increase was observed in the granulation tissue ingrowth between the cellulose fibres by 14 days, increasing a further 35% by 28 days. This study indicates that non-derivatized cellulose regenerated using ionic liquids has the potential to be used as a biocompatible alternative to proteinaceous biomaterials like keratin for biomedical applications. [ABSTRACT FROM AUTHOR]

The infiltration of naïve tissues by myeloid cells has been long related to their clearance and the physiological cell turnover, however, increasing evidence shows that they can additionally fulfill specific, non-immune functions in different tissues. There is also growing evidence to support that infiltrated granulocytes and monocytes respond to different environments by modulating gene expression and cytokine production, which in turn contribute to the normal function of the host tissue. This review will address the roles of immigrated myeloid cells in different tissues and their crosstalk with the host tissue environments. [ABSTRACT FROM AUTHOR]

In order to develop small-diameter vascular grafts, it is necessary to evaluate endothelialization, especially, in the center part at early stage. For implantation of vascular grafts of 1 cm in length to abdominal aortae of rat, endothelial cells can be formed easily by stretching anastomosis. We evaluated the endothelialization in the center part of vascular grafts by implanting vascular grafts using transgenic (TG) silk fibroin (SF) of 3 cm in length. Vascular grafts were prepared 1.5 mm in diameter and 1 and 3 cm in length using wild type (WT) SF and TG SF by braiding structure, respectively. The grafts were removed after 2 weeks or 3 months and evaluated pathologically. Endothelialization was not confirmed totally after 3 months of implantation. However, endothelialization in the center part of grafts was significantly higher in TG SF than in WT SF. No significant difference was found regarding tissue infiltration and internal diameter. The TG SF revealed migration of the endothelial cells into the center part of the vessels at the early stage. Also, tissue infiltration and remodeling is expected using SF. The 3 cm length vascular grafts can be evaluated as a new experimental system. [ABSTRACT FROM AUTHOR]