Serum amyloid A induces reactive oxygen species (ROS) production and proliferation of fibroblast

Abstract

Serum amyloid A (SAA) levels are elevated highly in acute phase response and elevated slightly and persistently in chronic diseases such as rheumatoid arthritis and diabetes. Given that fibroblasts exert profound effects on progression of inflammatory chronic diseases, the aim of this study was to investigate the response of fibroblasts to SAA. A dose-dependent increase in O2- levels was observed by treatment of fibroblasts with SAA (r=0·99 and P≤0·001). In addition, the expression of p47-phox was up-regulated by SAA (P<0·001) and diphenyliodonium (DPI), a nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitor, reduced the release of O2- by 50%. Also, SAA raised fibroblast proliferation (P<0·001) and this effect was completely abolished by the addition of anti-oxidants (P<0·001). These findings support the notion that, in chronic inflammatory sites, SAA activated fibroblast proliferation and ROS production. © 2010 The Authors. Clinical and Experimental Immunology © 2010 British Society for Immunology.