Hmm, this sounds like a rather premature announcement. They have
shown that the cells hone to damage and can get situated in
vasculature. But, there isn't any actual evidence yet that function
is being restored or if the cells will work long-term.
It reminds me of the stem-cell spinal cord repair done in Korea.
There was much excitement because in the animal models the cells
seemed to regrow gaps in the spinal cord and give significant
functional recovery. However, it was found that the same procedure
didn't work very well in humans and there was eventual cellular
rejection. Mice and rats simply have much less selective immune
systems than humans. Unrelated grafts have a much higher rate of
acceptance in those species than in humans. The whole embryonic
stem cell debate may end being a bunch of bunk if the trend for
eventual rejection continues. Logically, finding a way to use a
person's own cells is the best path of research, since there is zero
chance for rejection, except in the cases of autoimmune diseases, in
which there's no guarantee that any cells will work.
The only thing I've ever seen embryonic stem cells work in humans is
in artificial skin grafts, using stem cells on a matrix, but that
may only be because the embryonic cells last long enough for the
body's own skin cells to grow underneath and replace them. I'd have
to find a paper on the long-term histology of the treated skin to be
sure. I think the treatment used cord blood stem cells, actually.
It was from a Discovery Health program a year ago.
Received on Sun May 27 2007 - 16:55:17 CDT