Oxidative stress in scleroderma: Maintenance of scleroderma fibroblast phenotype by the constitutive up-regulation of reactive oxygen species generation through the NADPH oxidase complex pathway

The constitutive intracellular production of ROS by SSc fibroblasts derives from the activation of an NADPH oxidase-like system and is essential to fibroblast proliferation and expression of type I collagen genes in SSc cells. Our results also exclude O2-, H2O2, IL-1beta, TGFbeta1, PDGF-BB, IL-4, IL-6, TNFalpha, or CTGF as mediators of a positive, autocrine feedback mechanism of ROS generation.