Researchers able to direct stem cells to create certain progeny
Wed, 2008-08-06 18:21.
By: Sheryl Ubelacker, THE CANADIAN PRESS
TORONTO - Canadian researchers have found a way to control embryonic
stem cells so they give rise to only one category of cell, a first
step in medicine's quest to generate specific tissues to repair or
replace parts of the body that are diseased, damaged or just plain
worn out.
Embryonic stem cells are programmed to spawn all the different cells
of the body, from those that make up the brain or heart to those that
comprise the liver or skin. Scientists worldwide have been trying to
figure out the mechanisms that decide which cell becomes what.
In Wednesday's issue of the journal Stem Cell, scientists at
Toronto's Hospital for Sick Children describe how they prodded stem
cells to generate a single category of cell. Called early-stage
endoderm cells, they give rise to only certain tissues in the body.
"By adding a gene, we've essentially been able to take embryonic stem
cells, which make everything, and push them a little bit down one
particular pathway, the endoderm pathway," senior author Janet
Rossant, chief of research at Sick Kids Hospital, said in an
interview Wednesday.
"And that's the pathway of the cells that give rise to all the
tissues of the gut, to the lungs, to the liver, to the pancreas, to
very important cells that one day could be used for regenerative
medicine."
"These cells themselves would not be used for transplantation, but
they're a tool to help us understand that process."
Lead author Cheryle Sequin, a post-doctoral fellow in Rossant's lab,
said the researchers took existing embryonic stem cell lines and
manipulated their internal control mechanism by zeroing in on a
particular gene.
"So we created a new kind of stem cell, limited to making only one
cell type," she said.
Having accomplished this first step, the next research endeavours
will involve determining what other steps are needed to coax the stem
cells into begetting specific offspring, as it were, from lung cells
to repair the damage of cystic fibrosis to pancreatic cells that
could be transplanted into diabetics to provide insulin.
"It's just really about controlling stem cells, is really what it
comes down to," Seguin said. "We're one step closer to being able to
use these cells if we're one step closer to being able to control
what they can become."
Mick Bhatia, scientific director of the Stem Cell and Cancer Research
Institute at McMaster University, called the work an important
advance because it demonstrates that stem cell differentiation can be
controlled or directed, a prerequisite for their use in regenerative
medicine.
While embryonic stem cells' ability to produce any cell in the body
is what gives them so much promise, the challenge for scientists is
how to make them become what is needed for specific patients, Bhatia
said from Hamilton.
"How do you get a cell that can become over 200 different things to
become one thing and not the other 199?" he said, noting that many
scientists have argued that such control is not possible, that other
mechanisms govern the decision to become one cell type versus others.
Bhatia likened embryonic stem cells to students about to enter high
school, who have the option of taking courses to prepare for a career
in business, engineering or science, for instance. If they choose
engineering, they then have to decide what kind of engineering -
civil, industrial or electrical.
Continuing the analogy, he said the Sick Kids researchers have
directed the stem cells to take the endoderm (engineering) pathway;
the next step will be determining how to make them become lung cells
(civil engineering) or liver cells (electrical engineering)
"I think what they've done is establish a proof of principle that
stem cells can be directed in a very refined way," said Bhatia, who
was not involved in the research.
"And that's important to what they've shown here, but it's more
important to the broader issue of people asking: 'Can stem cells be
controlled?'
they can be controlled."
http://www.cjad.
«¤»¥«¤»§«¤»¥«¤»§«¤»¥«¤»«¤»¥«¤»§«¤»¥«¤»§«¤»¥«
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
StemCells subscribers may also be interested in these sites:
Children's Neurobiological Solutions
http://www.CNSfoundation.org/
Cord Blood Registry
http://www.CordBlood.com/at.cgi?a=150123
The CNS Healing Group
http://groups.yahoo.com/group/CNS_Healing
____________________________________________
«¤»¥«¤»§«¤»¥«¤»§«¤»¥«¤»«¤»¥«¤»§«¤»¥«¤»§«¤»¥«
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
Change settings via the Web (Yahoo! ID required)
Change settings via email: Switch delivery to Daily Digest | Switch format to Traditional
Visit Your Group | Yahoo! Groups Terms of Use | Unsubscribe
__,_._,___
No comments:
Post a Comment