Adult Stem Cell Treatment for Rheumatoid Arthritis

ABSTRACT

Since methotrexate began to be used in the treatment of rheumatoid arthritis (RA) 30 years ago, RA treatments have advanced rapidly from only reducing joint pain and inflammation to suppressing disease progression and joint destruction. In particular, the development of biologics and targeted anti-rheumatic drugs has almost made it possible to induce remission in patients with RA. On the other hand, the current RA treatments are still limited by adverse effects and treatment failure. Stem cell therapy has been suggested as an alternative treatment of RA, and preclinical studies and clinical trials using representative adult stem cells (ASCs), hematopoietic stem cells (HSCs) and mesenchymal stem cells (MSCs), are currently underway. HSC therapy in RA has mostly progressed based on the concept of ‘immune reset’, in which the existing immune cells are replaced with healthy ones. HSC transplantation was completed relatively safely, and the patients showed a positive treatment response. Nevertheless, the treatment response of HSCs in RA depends on the conditioning regimen, and the efficacy did not persist for a long time. The MSCs possessed a hypo-immunogenicity, immune modulation effect and tissue regeneration capability, making them another promising candidate for the RA treatment. MSC transplantation in RA was found to be safe with few adverse effects, such as immune rejection or embolism, but it showed a partial and transient response. This review addresses the characteristics of ASCs, focusing specifically on HSCs and MSCs, and summarizes the results of preclinical studies and clinical trials of ASC therapy in RA.