Adipose-Derived Stem Cell-Based Therapies in Regenerative Medicine

Abstract

Stem cell therapy is emerging as a viable and effective approach to the treatment of chronic and intractable diseases. Both embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) have been differentiated in the lab with high reproducibility into many tissue and organ cells. However, their routine application in clinical settings still requires substantial fine-tuning. Issues with mutations, tumorigenicity, differentiation efficiency, and ethical considerations hamper much anticipated clinical applications. Adult stem cells offer promising alternatives and do not suffer the same ethical and safety issues of embryonic cells. Adipose mesenchymal stem cells (ASCs) have been recently obtained from fat tissue, routinely collected from liposuction patients. ASCs appear to have many advantages that substantiate their use in clinical applications. They can be effectively harvested from fat tissue in large numbers and are genetically stable in long-term, in vitro culture. They have favorable immune-modulating functions in transplantation medicine, such as preventing severe graft-versus-host disease. Recent data from our laboratories shows that ASCs are more resilient, compared to bone marrow stem cells. This is evident in their resistance to hypoxic stress and alleviation of ischemia in vivo. Because of the recent history of ASCs, their use in the clinic was rushed without enough data on their quality, safety, or the reproducibility of the results obtained in the laboratory. Extensive preclinical studies are also lacking, especially when they are compared to other stromal cells, such as bone marrow MSCs. In this chapter, we will provide an overview of some of the aspects of isolation, characterization, and immunomodulatory properties of ASCs. We will also review some preclinical and clinical studies in which ASCs were applied, and showed some promise in regenerative therapy, and highlight challenges and future directions in using this promising form of cell-based therapy.