From: Brian D Williams (talon57@well.com)
Date: Fri Oct 02 1998 - 08:11:11 MDT
Tissue regeneration linked to genes
NEW YORK, Sep 30 (Reuters) -- A group of researchers say they are
close to identifying a group of genes linked to complex tissue
regeneration in mice. They believe their findings could
further research into human organ and limb regeneration after
trauma or illness.
After injury, wound healing in mammals usually involves repair
through cell proliferation rather than regeneration, which involves
replacement of damaged tissues. Mammals usually cannot regenerate
complex body structures, which can result in loss of function.
However, scientists at the Wistar Institute in Philadelphia,
Pennsylvania, say they have now identified a strain of mice
that ``undergo rapid and complete wound closure that resembles
regeneration.'' Their report is published this week in the
Proceedings of the National Academy of Sciences.
``What is remarkable,'' they say, is that these wound closures
``not only display full healing but also show the recovery of
normal architecture,'' including the regrowth of skin, cartilage,
blood vessel, hair follicles, and sebaceous glands -- all without
scarring.
After discovering that the ``MRL/MpJ'' strain of mice was able to
effect an apparent regeneration of damaged ear tissue, the authors
examined the mouse's genome (genetic 'blueprint') to seek out
genes associated with this process. The discovery of a mouse
capable of regeneration is particularly important, the scientists
say, since the genetic code of mice is both well-understood
and similar to that of humans.
The researchers say they have identified various areas of the mouse
genome thought to be home to ``at least five unlinked (mouse) genes
that can contribute to (this) healing.''
They report that one of the suspect genes is located in a
chromosomal region similar to that responsible for regeneration in
amphibians -- many species of which are capable of regrowing
whole limbs. Another gene has been linked to the production of
retinoic acid, a protein involved in mammalian tissue development
and the growth of skin.
In an interview with Reuters Health, Dr. Giovanni Rovera, director
of the Wistar Institute, explained that the final identification of
these genes will be only the beginning of regeneration
research. ``We understand so little,'' he said, ''but I think we
are one step closer.''
He believes the next logical step would be an exact identification
of the genes themselves. At the present time, he said, all we have
determined is an 'address' for the genes. ``I would compare it
to saying 'this is the town where these genes live,''' he
explained.
Of course, the 'holy grail' of this type of research would be the
development of a medical means of allowing humans to regrow limbs,
organs, or damaged spinal cords. However, Rovera cautioned that
experts ``suspect that regeneration of an organ or a limb is
controlled by many elements, of which these genes are only
representing one of those many elements.''
SOURCE: Proceedings of the National Academy of Sciences
1998;95:11792-11797.
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