Novel possible pharmaceutical research tools: stem cells, gene delivery and their combination.

Both stem cell research and gene delivery are very promising fields of today's biomedical research. In the present review we first attempt to summarize the state of the art in stem cell research. We describe the major categories of stem cells based on cell sources: embryonic, fetal, postnatal and induced pluripotent stem cells. We then present new data on stem cell cultures of dental pulp origin as examples of the progress of postnatal stem cell research. Afterwards, we briefly summarize the most promising achievements in the field of gene delivery. As an example of such advances, we describe novel in vitro and in vivo gene delivery studies to demonstrate that salivary glands are highly potential targets for gene therapy: they can be used to produce therapeutic peptides delivered either into the oral cavity or into the systemic circulation. Finally, we describe and compare studies combining the use of stem cells and gene delivery. We conclude that stem cell therapy and gene delivery alone are both very exciting research areas, and they may act in synergy when used in combination.