From: Jeff Davis (jdavis@socketscience.com)
Date: Mon Sep 13 1999 - 13:51:32 MDT
Friends,
Science advances at a blistering pace, a vast global flood welling up,
droplet by unnoticed droplet, from laboratories across the planet. In the
mass media, the news is sparse, being of little infotainment value.
Gina Miller, posing as that mild-mannered reporter for the obsure
cyberspacial mailing list "extropians", and assembling techno-newsworthy
tidbits under the psuedonymous byline "Nanogirl", offers the excerpt shown
at the end of this post.
However, embedded therein, easily lost amid the techno-ese is the following
comment:
>the fact ...<snip>... suggests that "...ex vivo
>expansion of transplantable human stem cells under this in vitro culture
system is a general
>phenomenon..."
Once more: "...expansion of... human stem cells in... culture is a
general phenomenon..."
Stem cells--the full range of stem cells-- are something of a biotech holy
grail. To fully exploit their potential will require the ability to
proliferate them in culture while retaining their polymorphic nature. The
above suggests a major step in that direction, with application to tissue
and organ regeneration, longevity, rejuvenation, and post-cryo repair.
*Culture system expands human hematopoietic stem cells
WESTPORT, Sep 10 (Reuters Health) - Using a stromal-based in vitro culture
expansion
system that they developed, US scientists report the successful long-term
ex vivo maintenance
and expansion of human hematopoietic stem cells suitable for
transplantation. Dr. Chu-Chih Shih
from the City of Hope National Medical Center in Duarte, California, and
colleagues there and
at Amgen Inc., in Thousand Oaks, describe their achievement in the
September 1st issue of the
journal Blood. The researchers cultured CD34+ thy-1+ cells on an
established monolayer of
murine stromal cells, AC6.21, with leukemia inhibitory factor (LIF),
interleukin-3 (IL-3), IL-6,
granulocyte-macrophage colony-stimulating factor and other cytokines. This
produced a
"...150-fold expansion of cells retaining the CD34+ thy-1+ phenotype" after
5 weeks of
culturing. These cells were capable of differentiating into "...myeloid, T
and B cells, when
transplanted into [severe combined immunodeficient-human] SCID-hu mice,"
according to Dr.
Shih's group. Dr. Shih and colleagues say the fact that another
hematopoietic stem cell
candidate, CD34+ CD38- cells, proliferate in a similar manner suggests that
"...ex vivo
expansion of transplantable human stem cells under this in vitro culture
system is a general
phenomenon and not just specific for CD34+ thy-1+ cells." Dr. Shih's group
hopes the culture
system will provide a valuable tool for identifying the factors involved in
"...regulating the
process of self-renewal, proliferation, and differentiation in early
hematopoietic development
and will have important implications for ex vivo stem cell expansion, gene
therapy and
therapeutic transplantation." Blood 1999;94:1623-1636.
Best, Jeff Davis
"Everything's hard till you know how to do it."
Ray Charles
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