Increased expression of Interleukin-13 and connective tissue growth factor, and their potential roles during foreign body encapsulation of subcutaneous implants. J Biomater Sci Polym Ed

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Journal of Biomaterials Science Polymer Edition (Impact Factor: 1.65). 08/2008; 19(8):1065-72. DOI: 10.1163/156856208784909408
Source: PubMed


The purpose of this study was to better understand whether interleukin-13 (IL-13) and connective tissue growth factor (CTGF) are highly expressed during foreign body encapsulation of subcutaneous devices. Mock biosensors were implanted into rats for three lengths of time (7-, 21- and 48-55 days) to address different stages of the foreign body response. Using quantitative real-time PCR and immunofluorescence, the expression of IL13, CTGF, collagen 1, decorin and fibronectin were measured in this tissue. IL-13, a product of Th2 cells, was highly expressed at all time points, with greatest expression at day 21. The IL-13 expression was paralleled by increased presence of T-cells at all time points. CTGF was also found to be more highly expressed in foreign body tissue than in controls. Collagen and decorin were highly expressed at the middle and later stages. Given the increased expression of IL-13 and CTGF in foreign body tissue, and their roles in other fibrotic disorders, these cytokines may well contribute to the formation of the foreign body capsule. Since the peak gene expression of IL-13 occurred later than the previously-reported TGFbeta expression peak, IL-13 is probably not the major stimulus to TGFbeta expression during foreign body encapsulation and may contribute to fibrosis independently.

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    • "As mentioned above, we have shown that inhibition of TGF-β signalling either by siRNA knockdown of TGFβRII or chemical inhibition of TGFβRII (ALK5) inhibits myofibroblast differentiation in vitro and peritoneal tissue capsule formation in vivo (Chau et al, unpublished data). However in light of the pleiotropic roles of TGF-β, a more suitable target for selective intervention may be the downstream effector, connective tissue growth factor (CTGF) which is responsible for many of the pro-fibrogenic effects of TGF-β (Ward et al., 2008; Brigstock, 2009). Conversely, chemokines/growth factors may be incorporated into biomaterials to promote tissue production for replacement/repair. "

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