around the world are learning more about stem cells and how they function to
help the body restore itself throughout the lifespan.
cells exist in all sorts of tissues throughout the body – they help the body to
continuously repair itself. And with the right stimulus, they can develop into
many different kinds of cells.
Keith March at Indiana University in Indianapolis recently learned more about
one kind of stem cell – it exists on the outer lining of blood vessels. He
explains that blood vessels have an inner lining which are called the
endothelial cells, and they have an outer lining which contain these stem
wondered whether those stem cells that were in the position of the outer wall
of the blood vessel were being, March says.
And we started experiments to test that question.
and his colleagues found that the two kinds of cells were indeed interacting. It turns out that the stem cells had the ability to keep the
epithelial cells strong – as long as endothelial cells sent the right
if the endothelial cells were diseased or damaged – for example, from high
blood pressure, high cholesterol or high blood sugar – stem cells on the
exterior walls of blood vessels transformed themselves into fat cells.
one of the things we think could happen is that as one gets these various
diseases, the endothelial cell actually becomes unhealthy, at the lining of the
blood vessel wall, March says. And as a result of that unhealthiness, it's no
longer able to restrain the stem cell from actually turning into a fat cell.
effect, March explains, the longer a person stays healthy, the less
likely he or she is to develop fat cells and become obese. But if blood vessels
start to become unhealthy, it starts a cycle of increasing fat, which makes the
blood vessels more diseased, which in turn creates more fat cells. He describes it as a viscious cycle.
see that there are signaling mechanisms that help to keep the fat stem cells
from turning into fat…as they turn into fat, or begin that process, those
signaling mechanisms are actually lost, March says. So it's almost like when you turn off the switch, that keeps it
from becoming a fat cell, the switches actually disappear from the wall.
says he and his colleagues are pursuing more research into these stem cells
that line blood vessels. He says that if they can learn more about how they
become fat cells, they might be a target for a drug that can help arrest the
process of becoming obese.
research is published in the journal Stem Cells.