2009 Volume 55 Issue 10 Pages 474-481
Three essential factors are considered to be necessary for tissue regeneration. The first essential factor is the presence of cells that bear the function of the desired tissue or organ, the second is the presence of signals that promote proliferation and differentiation of the desired cell type, and the third is a scaffold that acts as a foundation for the cells. Of these factors, obtaining stem cells is very important. Currently, there are several different types of stem cells that may be useful in tissue regeneration, including embryonic stem cells(ES cells), adult stem cells and induced pluripotent stem cells(iPS cells). ES cells are derived from the inner cell mass of the early blastocyst-stage embryo. Although ES cells are known to differentiate into various functional cells derived from all three germ layers, there are ethical issues, biological limitations and technical difficulties in the application of these cells. Adult stem cells have been identified in adult tissues such as bone marrow, muscle, neural tissue, liver and the adipose tissue. Since there are no ethical problems in their use and since they are relatively easy to collect, adult stem cells may overcome the weak points of ES cells. However, some reports of short cell life spans and limitations in their differentiation potency are distinct disadvantages to the use of adult stem cells. iPS cells, which can be created by transfection of 3 or 4 genes into adult somatic cells, possess a differentiation potency equal to ES cells. iPS cells can overcome the disadvantages of ES cells and adult stem cells, but their biggest drawback is that we have to conduct transfections in order to create these cells. With these points in mind, in this review, the multipotent characteristics of bone marrow stromal cells are documented, and the possibility of their application and a new strategy for tooth regeneration are also discussed.
