Current stem cell technology: Limitations and realistic expectations

The exploration of stem cells has always been strongly associated with the intent to advance more efficient tools for regenerative medicine, especially the repair of damaged tissue. To date, apart from very few working therapies, the success of this approach has been quite limited, and for clinical applications there are no immediate major breakthroughs in sight. Besides the known ethical and fundamental scientific issues, the reader should be pointed to a number of technical issues, that are believed to hamper the progress of applied stem cell research considerably: (i) The provision of a sufficient amount of stem cells with the propensity to differentiate into the desired cell type; (ii) The production of an ample amount of the desired cell type, which can afterwards effectively contribute to recover the impaired tissue; and (iii) The reliable exclusion of pathological side effects, like cancer generation or immunological host versus graft reactions. Here, the authors propose that some of these difficulties might be overcome by employing alternative stem cells, like adult stem cells from exocrine glands. Additionally, the authors suggest some novel uses of stem cells, which are not directly aimed at regenerative medicine and have received comparatively little attention, although they are readily available.