[Perspectives on regenerative therapy]

Organ transplantation and artificial organs are the only effective treatments for loss of organ and tissue function. These treatments, however, are associated with serious problems such as a critical shortage of donor organs, rejection, the need for life-long immunosuppression, and unstable biocompatibility. These shortcomings have stimulated the development of tissue engineering. Tissue engineering is defined as an interdisciplinary field that applies the principles of engineering and the life sciences to the development of biological substitutes that restore, retain, or improve tissue function. Tissue engineering is composed of three factors: cells; growth factors; and scaffolds. Regenerative medicine includes two important fields: tissue engineering; and regenerative biology. Regenerative therapy is a newly developed medical therapy based on the research results of regenerative medicine. The fields of regenerative therapy includes broad areas of basic and clinical sciences, bioethics, and medical economics in addition to the area of regenerative medicine. Cell sources and cell expansion are important issues in regenerative medicine. Great efforts are being made to isolate and identify the characteristics of stem cell populations of various tissues. The use of stem cells may provide an almost limitless supply of cells for transplantation. Although there are still many important issues to be resolved, regenerative medicine has been making rapid progress using a multidisciplinary approach. The success of this approach will lead to the widespread application of regenerative therapy and may ultimately be able to replace lost tissue function in the 21st century. We should, however, keep in mind the importance of bioethics in using any new therapy.