Overview of Animal Models

Experiments on cellular components isolated from affected tissues are essential to provide the first proof of concept of human diseases, but there is a pressing need to further validate the results in vivo. Systemic sclerosis (SSc) is not an exception; animal models are crucially required to close the gap between in vitro studies and clinical trials. This translation from bench to bedside has long been hindered by a paucity of suitable animal models, as well as insufficient characterization of the existing models; however, this has changed over the last years. Several promising animal models of SSc have recently been described. Furthermore, intensive characterization of the existing models greatly improved our understanding of the strengths and limitations of preexisting models. Unfortunately, no current animal model manifests the whole range of pathological features seen in patients. Instead, in most models, only a fraction of disease manifestations are modeled, reflecting the limitations of our understanding of underlying pathogenesis. Thus, a comprehensive description of mouse models of SSc requires consideration of a vast array of animal models of fibrosis, inflammation, autoimmunity, and vascular injury. This chapter describes traditional models of SSc in more detail, but also provides a more comprehensive review of models, including emerging disease models. We aim to highlight that a wise combination of complimentary models can booster our understanding of the molecular pathogenesis of SSc and might support the development of novel targeted therapies.