Culture of stem cells

Jeff Davis (jdavis@socketscience.com)
Mon, 13 Sep 1999 12:51:32 -0700

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