[extropy-chat] BIO: Stem Cell Genes

[Robert J. Bradbury]

On Tue, 23 Dec 2003, Dirk Bruere wrote:

> The big question IMO is whether these are 'old' stem cells.
> What's the state of their 'clock'?

The clock's state will be most likely be "older", though perhaps
not as old as adult cells in the body.  Aubrey, Rafal and I have
discussed this in some older notes over the last 6-12 months.

Aging (IMO) is ultimately caused by the misrepair of DNA double
strand breaks.  There are a host of things you can get leading
up to that -- point mutations (leading to cancer), undigestable
molecules leading to lipofuscin accumulation, protein glycosylation
leading to hardening of the arteries, shortening of telomeres leading
to decreased immune system response and reduced cellular replication
potential and increased cellular scenescence and probably a host
of other things.  Aubrey's IBG proposals and SENS work are trying
to deal with those things that are right up in front of our faces
and find solutions.  But ultimately when you solve all of those
problems I think DNA misrepair is going to get you unless we
have the technology to replace or rewrite the defective genomes.

Replacement comes from finding the least aged stem cells.  That
is going to require either very high throughput (and inexpensive)
gene expression measurement capabilities (probably with gene chips)
or very inexpensive whole genome sequencing.  Take 100 stem cells,
duplicate them, find the most perfectly intact genome in the clones
and then use the original cell to produce billions of copies for
therapies.

Rewrite is going to require the Freitas Chromallocytes that can
take out an old grungy genome and replace it with something better.
That will require real MNT.

The good thing is that we have parallel strategies that do not
seem to depend on the same technologies.

Robert