The problem with stem cells, is that they like to form tumors when placed in the body, so programming a stem cell to do what you want is very difficult, we dont know alot about stem cells, and how they are able to differentiate. iN DIABETES pn, people dont even know how nerves are damaged by being diabetic. Let say it works, but the healing will reverse itself, because you are still diabetic(assuming your not type 1) and the damage will re-occur even after treatment.