[Stem cell research in gastroenterology]

Stem cells are undifferentiated cells capable of undergoing self-renewal and differentiation into a variety of cell types. They are derived from adult tissues (adult stem cells) as well as embryonal blastocysts (embryonic stem cells). Embryonic stem cells have pleuripotent capacity able to form tissues of all three germ layers but many ethical controversies concerning resource allocation or methods of harvesting are arising. Recently, many studies have demonstrated the multipotency of adult stem cells, but the mechanism of the plasticity remains to be determined yet. Several studies have suggested the possibilities of application of stem cells or tissue specific cells to regenerate gastroenterologic diseases such as liver cirrhosis, hepatitis, or inherited metabolic disorders. However, most of those trials are still limited to animal models, although anecdotal claims of successful therapy in humans have been reported. Even though the expectations and the promise of cell therapy are high, clinical efficacy has not been definitely demonstrated at this time. Thus, the application of cell therapy cannot be recommended to the patients outside the clinical trial setting.