Goldman”s research team has been injecting the controversial cells into rats that have the disease and the cells turned into tumors afterwards.
The scientists explained their findings in an article in the latest issue of Nature Medicine.
They said the embryonic stem cell injections helped some of the rats but some of the cells started growing in a manner that would eventually lead to a tumor.
“The behavioral data validate the utility of the approach. But it also raises a cautionary flag and says we are not ready for prime time yet,” Goldman told the Washington Post.
He conceded that considerably more research would need to be done to determine whether the tumor problems could ever be overcome.
Parkinson”s is a disease where dopamine-releasing cells in the brain die out, which leads to muscle dysfunction and can eventually cause paralysis. The goal of stem cell research in Parkinson”s is to replace the dead cells with stem cells that form into new dopamine cells.
Goldman”s team used human embryonic stem cells obtained by killing days-old unborn children that were grown in a special chemical used to coax them into becoming brain cells.
The team killed the rats before they could determine that the tumors that appeared to be growing actually finished appearing and they said that any embryonic stem cell treatments on humans, which has never been tried, would have to be closely monitored.
Some autopsies on the rats found tumors and that the embryonic stem cells began to grow uncontrollably rather than becoming the dopamine cells as intended.
Another team led by Ole Isacson, a Harvard Medical School professor of neuroscience and neurology, published similar results earlier this month in the online journal Stem Cells and found that the embryonic stem cells also produced tumors.
Adult stem cells have not had the same problems and have been used successfully to treat dozens of diseases and conditions. But scientists have said they don”t think embryonic stem cell research will lead to a cure for Parkinson”s.
University of Melbourne Emeritus Professor of Medicine Thomas Martin told Australian lawmakers recently that he did not think that embryonic stem cell research would even lead to cures for major diseases such as diabetes or Parkinson”s.
Martin, an internationally recognized Fellow of the Royal Society, said the embryonic stem cells produced from human cloning would have the same problems.
by Steven Ertelt
October 23, 2006