For diseases and conditions for which there is no acceptable treatment- like paraplegia and stroke, for example, the FDA is lenient in allowing companies to try new approaches.
Two such studies that I am aware of have, unfortunately, failed. Stem Cells, Inc is now winding down its business after many years of effort in trying to provided neurological return to patients with paralysis. Such studies attempt to deliver stem cells to the site of spinal cord disruption in the hope that they will “reconnect” nerve endings. One must realize that some return can seem to occur even without stem cells,,so the noise is such a trial is significant, especially when the number of patients is very, very small (less than 10). So, after a bit of early optimism there is no evidence that the therapy really helps…
Another failed trial was run for hemiplegic stroke by the Cytomedix, Inc, using a particular market for stem cells called ALDH and injecting these cells into the carotid artery. 50 patient treated in “blind” fashion failed to show a difference.
BUT, recently, a team from Stanford shows that the efforts keep on coming; this approach, for stroke patients, injected the stem cells directly into to the brain (through a small hole in the skull). Early results look amazing, but we have all been here before. If and when another group repeats the study, it may be that the route of administration is critical; also it may be that the stem cells simply work by secreting growth factors that allow brain cells to repair themselves. (I would bet on this one).
If that proves to be the case, we will gradually learn that neural tissue, like cartilage, far from being unable to regenerate, can sometimes regenerate if the triggers for cell growth are present.
Wouldn’t that be nice?