Autologous stem cells in neurology: is there a future?

Stem cells seem very promising in the treatment of degenerative neurological diseases for which there are currently no or limited therapeutic strategies. However, their clinical application meets many regulatory hurdles. This article gives an overview of stem cells, their potential healing capacities as well as their identified and potential risks, such as tumor formation, unwanted immune responses and the transmission of adventitious agents. As there is no clinical experience with embryonic and induced pluripotent stem cells (as the result of their unacceptable risk on tumor formation), most attention will be paid to fresh autologous adult stem cells (ASCs). To evaluate eventual clinical benefits, preclinical studies are essential, though their value is limited as in these studies, various types of stem cells, with different histories of procurement and culturing, are applied in various concentrations by various routes of administration. On top of that, in most animal studies allogenic human, thus non-autologous, stem cells are applied, which might mask the real effects. More reliable, though small-sized, clinical trials with autologous ASCs did show satisfying clinical benefits in regenerative medicine, without major health concerns. One should wonder, though, why it is so hard to get compelling evidence for the healing and renewing capacities of these stem cells when these cells indeed are really essential for tissue repair during life. Why so many hurdles have to be taken before health authorities such as the European Medicine Agency (EMA) and/or the Food and Drug Administration (FDA) approve stem cells in the treatment of (especially no-option) patients.