Stem cells taken from human fat can be transformed into
smooth muscle cells, offering a way to treat many kinds of heart disease,
gastrointestinal and bladder ills, US researchers reported on Monday.
A microscopic view of undifferentiated human
embryonic stem cells. California Gov. Arnold Schwarzenegger moved on
Thursday to provide his state's voter approved stem-cell research
institute with a loan of up to $150 million.
[Reuters] |
While the experiment does not quite offer a way to turn a pot belly into a
flat stomach, the researchers said the transformed cells contracted and relaxed
just like smooth muscle cells.
These cells help the heart beat and blood flow, push food through the
digestive system and make bladders fill and empty, the researchers reported.
Their study, published in the Proceedings of the National Academy of
Sciences, is the latest to show that fat can be a rich source of the body's
master cells.
"Fat tissue may prove a reliable source of smooth muscle cells that we can
use to regenerate and repair damaged organs," said Dr. Larissa Rodriguez, an
assistant professor in the Department of Urology at the University of California
Los Angeles medical school.
And almost any American has plenty of spare fat cells.
Rodriguez and colleagues incubated adipose-derived stem cells in a nourishing
mixture of growth factors, human proteins that encouraged the cells to become
smooth muscle cells.
The researchers said scientists have been looking for sources of smooth
muscle for organ repair and treating heart disease, gastrointestinal diseases
and bladder dysfunction.
"A major obstacle for such an approach has been finding a reliable source of
healthy smooth muscle cells that can be safely harvested and that requires
minimal manipulation," they wrote.
Clean, Healthy Fat
One approach has been to take a patient's own cells from an organ. But
studies have shown that stem cells taken from a diseased organ are also damaged
and do not work well when scientists try to grow them in the lab for a
transplant.
Transplants grown from a patient's own fat could be used with no need for
anti-rejection drugs, Rodriguez said. Smooth muscle cells have been produced
from stem cells found in the brain and bone marrow, but acquiring stem cells
from fat is much easier, she added.
The stem cells found in fat are known as multipotent stem cells. They can
produce a variety of cell and tissue types, but are not as flexible as embryonic
stem cells.
Last week, President George W. Bush vetoed a bill that would have broadened
federal funding of human embryonic stem cell research, saying he preferred that
researchers pursue so-called adult stem cells, such as those used at UCLA.
Many groups have been looking to fat as a source of stem cells. In April,
Cytori Therapeutics Inc. said it was starting a clinical trial to test whether
stem cells derived from fat can be used to regenerate breast tissue.
Other researchers have been trying to get stem cells from liposuction
specimens.
In a second study published in the same journal, British researchers said
they found one important protein that keeps stem cells in a quiescent and
non-dividing stage.
Fiona Watt of Cancer Research UK and colleagues studied stem cells from human
skin and found a protein known as Lrig1 kept the skin cells from proliferating.
When Lrig1 production was silenced, the stem cells began growing and dividing.
The finding may not only offer important information to stem cell
researchers, but may also offer insights into cancer, Watt's team said. In
cancer, cells ignore the normal signals from the body and proliferate
uncontrollably.
The protein is also involved in psoriasis.
