Parkinson’s disease is thought to be caused by missing dopamine neurons. Stem cell research has sought a way to restore the missing dopamine neurons, but often the immune system rejects the transplanted cells.

Lorenz Studer, MD, Head of Stem Cell and Tumor Biology Laboratory, Sloan-Kettering Cancer Center, feels that their latest study reduces the chances that somatic-cell nuclear transfer (SCNT)–or therapeutic cloning–reduces transplant rejection and enhances recovery in diseases and organ systems.

In SCNT the nucleus of a donor subject’s somatic cell is inserted into an egg, which has had the nucleus removed. This cell then develops into a blastocyst from which embryonic stem cells can be harvested for therapeutic purposes. Since the genetic information in the resulting stem cells comes from the donor subject the SCNT has a greater chance of being accepted by the immune system.

Scientist demonstrated the process on mice genetically designed to have Parkinson’s disease. They began by taking skin cells from the tails of mice and generated the missing dopamine neurons–the cause of Parkinson’s–but because they did not attempt to genetically match the transplanted cells, from donor to recipient, the cells did not survive and the mice did not recover.

Using SCNT, where the transplanted stem cells were from the same subject, the immune system accepted the transplanted cells and the mice showed signs of recovery.

Studer’s article appears in the March 23, 2008 online journal edition of Nature Medicine.