Doug,
I am not an expert on this, but I went to a meeting of the Wisconsin
Parkinson Foundation on May 17, 2002, where Dr. Clive Ivenson of the
University of Wisconsin, an expert in stem cell transplantation and "brain
repair," said the following:
The studies with GDNF showed "dramatic results" and no serious side
effects: in monkeys the degeneration of neurons was slowed and there was an
"enhancement effect" where new neurons were produced;
GDNF is a big protein, and the problem is getting it across the brain
blood barrier;
The use of stem cells as the transport mechanism for GDNF is the
future for stem cell research;
Neurons are very difficult to produce in the process of manipulating
the blastocyst to differentiate into a specific type of cell in stem cell
transplantation; dopamine-producing neurons are extremely difficult to
produce;
Using stem cell transplantation to carry the GDNF avoids the problem
of getting GDNF across the brain blood barrier and the problems of the
difficulty of making dopamine-producing neurons and making the
dopamine-producing neurons in sufficient quantity for transplantation.
Presumably using stem cells to carry GDNF would also avoid all the
problems and difficulties of gene or virus techniques. (My conclusion: he
did not even mention that research in his presentation).
Of interest:
He said that he would never use foetal tissue for transplantation due
to the lack of uniform results, the need to use the foetus at exactly eight
weeks, and the need to use five foetuses for each side of the brain.
He said that 250 people in the world have received stem cell implants,
and only three have exhibited extreme, unpredicted side effects as those
reported in the infamous N.Y. Times article. He said that in 1000 rats there
is no showing that the stem cell transplants result in tumors or unchecked
proliferation of the transplanted cells.
He said that changing red blood cells in the umbilical cord into
dopamine-producing neurons was "science fiction" given the current state of
technology. Even with the rapid pace of development with stem cell research,
he did not think that, even in 10 years, this was a possibility. He said
that the costs of storage of the umbilical cord were high, and may not be
worth it.
He said that "the immune system does not go beyond the brain blood
barrier," and there is no serious issue of rejection of the transplanted
cells in the brain. This makes stem cell transplantation in the brain
significantly different from stem cell transplantation in other body parts
where the rejection of the transplanted cells is a complicating factor.
He said that he and his colleagues were very aware that they could
not even get one bad result in their research. He said that the media would
pounce on a bad result, and it would effect his funding and potentially the
entire area of stem cell research.
I think I have reported this as accurately and clearly as I can.
Remember that I was a lawyer, and not a scientist. I found this all very
interesting--and very hopeful. Research is developing at an extremely rapid
pace, and in all directions. Unfortunately, IMO, the political/legal arena,
the religious/ pro-life groups, and the ever-vigilent media can slow or stop
this promising research. Katie from Green Bay
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