Human embryonic stem cells—potential applications for regenerative medicine

Human embryonic stem (hES) cells attract profound scientific and public attention due to their far-reaching potential applications in regenerative medicine. Given the capability of hES cells to proliferate extensively in culture and their pluripotent potential, hES cells may serve as a renewable unlimited source of cells for transplantation therapy. In addition, genetically manipulated, transplanted hES cells may serve as vectors that carry and express genes in target organs in the course of gene therapy. While hES cells show great promise, bulk cultures of standardized cells suitable for clinical trials should be developed, and additional research is required to control the growth and differentiation of the cells and to overcome the risk of tumor formation and graft rejection. The recent development of humanized, feeder-free culture systems, methods to genetically modify the cells, and strategies to derive highly enriched populations of differentiated cells of a specific type are encouraging. It is anticipated that these achievements will set the stage for further developments that may eventually allow the exploitation of the great potential of hES cells for cell and gene therapy.