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Researchers produce blood in lab from stem cells
Posted on Monday, August 25, 2008 (CDT) by Thoth
 Scientists said Tuesday that they had devised a way to grow large quantities of blood in the lab using human embryonic stem cells, potentially making blood drives a thing of the past. But experts cautioned that although it represented a significant technical advance, the new approach required several key improvements before it could be considered a realistic alternative to donor blood.
The research team outlined a four-step process for turning embryonic stem cells into red blood cells capable of carrying as much oxygen as normal blood. The procedure was published online by the journal Blood.
The ability to make blood in the lab would guarantee that hospitals and blood banks have access to an ample supply of all types of blood, including the rare AB-negative and the universal donor type, O-negative.
It would
also ensure that patients are never at risk of contracting diseases
such as hepatitis C or HIV from donor blood, said Dr. Dan Kaufman,
associate director of the University of Minnesota's Stem Cell
Institute, who wasn't involved in the study.
"People don't usually think
about these types of cells when they talk about human embryonic stem
cell therapy, but it is important," Kaufman said. "There's more
infections all the time, and the number of donors is more and more
limited."
Researchers have tried to
harness the so-called adult stem cells that are responsible for making
blood in the body, but their methods were far too inefficient to be put
to practical use, experts said.
In the new study,
researchers were able to make as many as 100 billion red blood cells --
enough to fill two or three collection tubes -- from a single plate of
embryonic stem cells.
After allowing the stem
cells to begin the earliest stages of embryonic development, the
researchers prompted some of them to grow into red blood cells by
exposing them to a variety of proteins.
Up to 65% of the resulting
cells matured to the point at which they shed their nucleus, which
allows them to take on the distinctive doughnut shape of circulating
red blood cells, said Dr. Robert Lanza, chief scientific officer at
Advanced Cell Technology Inc. and the study's senior author.
The team, which also
included researchers from the University of Illinois at Chicago and the
Mayo Clinic in Rochester, Minn., produced blood of types A-positive,
A-negative, B-positive, B-negative and O-positive.
The method was 100 times
more efficient than previous efforts, said Eric Bouhassira, a professor
of stem cell biology and regenerative medicine at Albert Einstein
College of Medicine in New York. But most of the cells had embryonic or
fetal versions of globin, the compound in red blood cells that carries
oxygen. Only a relative few appeared to contain the adult globin that
would be needed by patients, he said.
"Whether they would be good
enough for transfusion is very unclear," said Bouhassira, who wasn't
involved in the study. Lanza said the research team was conducting more
experiments to see whether the stem cells would produce more adult
globin if given more time to mature in the lab.
Even with substantial
improvements, the method faces another big hurdle. Roger Dodd, director
of the American Red Cross' Holland Laboratory in Rockville, Md., said
that producing blood in the lab could cost thousands of dollars per
unit -- far too expensive to replace the 14 million pints of red blood
cells that are transfused every year. "It's a rather ambitious goal,"
Dodd said.
Copyright: Los Angeles Times
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