Perspectives on Stem Cell-Based Regenerative Medicine with a Particular Emphasis on Mesenchymal Stem Cell Therapy

Regenerative medicine is a medical treatment that aims to restore lost human body functions by regenerating missing or dysfunctional organs and tissues using stem cells, etc. There are three major types of stem cells used in regenerative medicine: induced pluripotent stem cells (iPS cells), embryonic stem cells (ES cells), and mesenchymal stem cells (MSCs). MSCs are expected to be widely applied to regenerative medicine because of their ability to differentiate into various types of cells, repair cells and tissues; anti-inflammatory effects; secretion of various growth factors; and resolution of abnormally accumulated protein amyloid. MSCs can be derived from bone marrow, dental pulp, and other sources, but adipose tissue-derived stem cells (ADSCs) may be superior in that they can be harvested with the least amount of invasion, and therefore, a sufficient amount of stem cells can be cultured relatively easily. When MSCs are administered systemically by intravenous infusion, they tend to accumulate at the site of disease, a property known as "homing," which is extremely advantageous for clinical applications. In Japan, stem cell therapy can be performed only after the research or treatment plan has been reviewed and approved by the "Committee for Specific Approval of Regenerative Medicine" and submitted to the Ministry of Health, Labor and Welfare for approval in accordance with the "Act on Securing the Safety of Regenerative Medicine" and after approval by the ethics committee of the facility where the therapy is performed. In this review, the characteristics of MSCs, the actual status of their clinical application, and their future prospects are presented.