Rheumatoid arthritis research in the 21st century: Limitations of traditional models, new technologies, and opportunities for a human biology-based approach.

Rheumatoid arthritis (RA) is a chronic systemic autoimmune inflammatory disease characterized by progressive bone and cartilage destruction, functional impairment, and long-term disability. Although RA has been described in the medical lit­erature for over two hundred years, its etiology and pathophysiology are insufficiently understood. The current treatment of RA is mainly empirical or based on drugs that interfere with generic steps of the immune response, with limited efficacy and/or significant side effects. Much of RA research has been traditionally based on animals and simplistic in vitro models, which have been shown to poorly recapitulate human RA etiopathogenesis and drug responses. A revolution in science and technology has produced a new generation of more relevant and predictive tools. These tools, which include patient-derived cells, innovative 3D cell culture systems, computational analyses and models, together with omics and large-scale epidemiological studies represent novel and exciting approaches to enhance and forward RA research in a human biology-based perspective. After considering some pitfalls and flaws of traditional models, in this review we discuss novel tools applicable to design human-oriented RA research, while fostering the need for a more holistic and pre­ventative approach to the disease. Our goal is to stimulate discussion, both at scientific and public level, on the need to explore new avenues in RA research and to support a paradigm-shift from animal-based towards human biology-based systems to better understand human pathophysiology and to develop more effective targeted therapies for personalized treatment and prevention.