BIO/ETHICS: Human Brain Cells in Mice

From: Greg Burch (
Date: Fri Mar 02 2001 - 06:51:37 MST

This story is interesting in itself, but also especially for the comment
made by one of the principal researchers: "It is not the objective to go
make mice with human brains,'' Weissman said. ``(But) it is in the domain
of the ethicists, not the experimenters, to figure out what our limits are."
 This kind of statement REALLY bugs me. I can understand why, for "political"
reasons, biotech researchers say these kinds of things these days. They
want to make a monkey-bow to supposed authorities outside of the scientific
enterprise to assuage people's fears of the Frankenstein archetype. It
also will be a practical way to simply not have to spend a lot of time with
reporters answering questions the scientist may feel aren't the best use
of her time. But, to the extent that it reflects a real defference to "ethicists",
I feel it represents a kind of moral and general philosophical cowardice
on the part of the people doing this kind of work, which ultimately fuels
a mistrust of the entire enterprise by non-technical people.

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Friday February 23 9:18 PM ET
U.S. Scientists Craft Mouse with Human Brain Cells

By Andrew Quinn

SAN FRANCISCO (Reuters) - U.S. researchers have produced laboratory mice
with human brain cells, marking a potential step toward developing treatments
for human brain disease like Alzheimer's but promising to fuel fresh debate
over the evolving ethics of bioengineering.

The research at California biotechnology company StemCells Inc. breaks new
ground by demonstrating that human brain stem cells can be induced to grow
within a mouse's skull, scientists said on Friday.

``We are not recreating a human brain. We're really just trying to understand
how these stem cells can function, and how they can be used in the treatment
of specific diseases,'' said Ann Tsukamoto, vice president of scientific
operations at StemCells Inc.

Irving Weissman, a Stanford university professor involved in the two-year
research project, said the next step could be to produce mice with brains
made up almost entirely of human cells -- although he said there would have
to be a thorough ethical review before this step is taken.

``You would want to ask the ethicist what percentage of the brain would
be human cells before you start worrying, and if you start worrying, what
would you start worrying about,'' Weissman said.

The California study involved isolating human stem cells in the laboratory
and then introducing them into mice. As the mice matured, the human stem
cells -- ``master cells'' that can develop into any other type of cell --
grew into a full range of specialized cells throughout each mouse brain.

``It looks like human cells can follow the developmental instructions put
in by the mouse brain. They are making human components in what is clearly
a mouse brain,'' Weissman said.

The researchers believe that these mice could be used to test treatments
for human brain diseases such as Parkinsons and Alzheimer's, although these
tests have not yet been undertaken.

Tsukamoto added that the experiment also demonstrated that StemCell Inc's
process for isolating and developing human stem cells was viable, and that
cell banks could be established for future transplantation into humans.

``We're of course moving this into the development phase, and looking at
which disease indications these cells would be best used for in preclinical
trials,'' she said.

Both scientists stressed that their research, while marking a new breakthrough
in the controversial world of stem cell research, was in no way aimed at
blurring the lines between human and animal.

But Weissman added that he had already requested a review panel to look
at the research to determine if there may be ethical problems in taking
the work further.

``It is not the objective to go make mice with human brains,'' Weissman
said. ``(But) it is in the domain of the ethicists, not the experimenters,
to figure out what our limits are.''
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       Greg Burch -
     Attorney::Vice President, Extropy Institute

    "We never stop investigating. We are never
      satisfied that we know enough to get by.
   Every question we answer leads on to another
      question. This has become the greatest
          survival trick of our species."
                -- Desmond Morris

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