NEWS : Stem cells turned into organ precursors

["ljherman1@xxxxxxxx" <ljherman1@xxxxxxxx>]

FROM: Science Daily 

Stem cells turned into organ precursors
By STEVE MITCHELL
WASHINGTON, Oct. 28 (UPI) -- Scientists said Friday they have for the first 
time turned embryonic stem cells in the lab into a type of cell that can give 
rise to several internal organs, including the pancreas, liver and lungs.
    
The advance is seen as a breakthrough that will enable scientists eventually to 
use the stem cells to repair diseased or damaged tissue. It likely also will 
facilitate the use of the cells for studying how diseases originate, which 
could lead to insights about cures and treatments.

Because embryonic stem cells have the capability to give rise to all the 
different cell types found in the human body, scientists think they can be 
harnessed to regenerate specific regions of the body, such as the brain or 
heart. The trick is determining the precise combination of chemical compounds 
needed to trigger the stem cells to become a specific cell type.

Now, Emmanuel Baetge of CyThera Inc., in San Diego, and colleagues report in 
the December issue of Nature Biotechnology they have figured out a key piece of 
that puzzle and come up with a mix that spurs the stem cells to develop into 
endoderm -- a layer found in developing embryos that gives rise to the thyroid, 
thymus, lungs, liver, pancreas and the lining of the respiratory and digestive 
tracts.

"We have described an approach to produce highly enriched cultures of 
definitive endoderm from (human embryonic stem cells)," Baetge's team wrote. 

The technique is "a critical step in generating scientifically and 
therapeutically useful cells of the definitive endoderm lineage, such as (liver 
cells) and pancreatic endocrine cells," the scientists added. 

"It basically shows human embryonic stem cells have the capacity to make this 
lineage and all the resulting cells that come from that that make up all these 
organs," Baetge told United Press International.

"If you were to use human embryonic stem cells to make products that treat 
disease, such as diabetes or liver failure, you'd have to go through the 
endoderm stage to get to it," he added.

Baetge's company, CyThera, is focused on using stem cells to generate an 
unlimited supply of islet cells, which are found in the pancreas and produce 
insulin, to treat diabetes.

Outside scientists also hailed the advance.

"Endoderm is one of the most therapeutically important and most difficult to 
obtain, so this is certainly a very important step," Dr. Robert Lanza, vice 
president of medical and scientific development at Advanced Cell Technology, 
told UPI. Advanced Cell, a biotech company based in Worcester, Mass., is 
seeking to develop medical therapies from stem cells. 

Beyond the direct therapeutic applications, the finding also has "massive 
implications" for developing new drugs and understanding human development, 
Baetge said.

Pharmaceutical companies could use the technique to generate an unlimited 
supply of human tissues, such as liver cells, for screening potential new 
drugs, he said. The cells could also be used to study cancer and "all kinds of 
aspects of what might go wrong as a human cell is developing," he added. 

The scientific consensus is embryonic stem cells hold great potential for 
generating insights and even treatments for disease, but the research is 
controversial because it involves the destruction of an embryo, which some, 
including President Bush, equate with taking a human life. 

Bush has limited federal funding of the research to stem-cell lines that 
already were in existence in 2001. This meant CyThera had to use private funds 
for its research, because three of the eight stem-cell lines they used were not 
on the list approved by the administration. 

The administration's policy has been criticized for hampering progress in the 
stem-cell field, and both Congress and the scientific community have begun 
taking steps to circumvent it. 

Meanwhile, scientists recently announced new methods for obtaining stem cells 
that may avoid some of the ethical hurdles associated with conventional 
techniques, but it remains unclear if the techniques, which were developed 
using mice cells, will hold true for human cells. In addition, these techniques 
are not intended to replace conventional techniques but rather to provide an 
alternative for those who object to the destruction of embryos.

The House in May passed the Stem Cell Research Enhancement Act, which would 
relax some of Bush's limitations on stem-cell research and allow federal 
funding to go towards research involving surplus embryos from fertilization 
clinics that would otherwise be destroyed. The Senate appears poised to pass 
the legislation, but a vote on it has been delayed until next year, and Bush 
has said he will veto it.

Lanza said Baetge's research underscores the limiting impact of Bush's policy. 
He noted that different stem-cell lines reacted differently to the technique 
and said Advanced Cell found the same thing with some of their research. 

Each stem-cell line is unique and has its own set of characteristics, "so we 
need access to more and better quality stem-cell lines," Lanza said. "Until 
that happens, this field is going to hobble along rather than sprint to the 
goal post," he added.

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Copyright 2005 by United Press International. All Rights Reserved.

http://www.sciencedaily.com/upi/index.php?feed=Science&article=UPI-1-20051028-14580200-bc-us-stemcells.xml#

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