Abstract
Cell therapy involves transplantation of cells to replace damaged tissues and cells and is used in regenerative medicine. Since its introduction, numerous cell therapy modalities have been developed to treat various diseases, and cell therapy has shifted the paradigm of the treatment of degenerative and refractory diseases. However, it faces limitations in terms of long-term therapeutic effects and efficiency. To overcome these challenges, the concept of co-transplantation, which utilizes two different cell sources, has been proposed. Stem cell-based co-transplantation approaches have been extensively studied both experimentally and clinically for various diseases, including graftversus- host disease (GVHD), infertility, acute liver failure (ALF), and myocardial infarction (MI). These have yielded improved transplantation efficiency and stability compared to single-cell transplantation methods. This review examines the development and effectiveness of co-transplantation through its application in four diseases. Additionally, it discusses the clinical applicability of cotransplantation, explores future research directions, and highlights its potential benefits.