Stem Cells Show Promise
FYI Only!!!!
Stem Cells Show Promise Against Diabetes
By Nicolle Charbonneau
HealthSCOUT Reporter
MONDAY, Feb. 28 (HealthSCOUT) — Scientists have used stem cell therapy to
transplant insulin-producing cells into diabetic mice, reversing their
disease.
Their findings, while at an early stage and accomplished in a small
number of mice, raise hope for more than 15 million Americans suffering from
diabetes. However, diabetes experts suggest that the research published in
the March issue of Nature Medicine still faces several technical hurdles.
Diabetes affects the islet cells of the pancreas, an organ near your
stomach. Islet cells produce insulin, without which your body can’t convert
the sugar in our food into energy. When diabetes destroys islet cells or
when we can’t use insulin properly, patients need to monitor their blood
sugar levels and self-inject insulin daily.
But insulin treatment is not perfect. Diabetics are at higher risk of
cardiovascular problems, nerve damage and other complications. Other avenues
to treat diabetes are being researched. Most recently, a paper in the
February issue of the journal Diabetes described using embryonic mice stem
cells to create islet cells.
But researchers at the University of Florida are taking a slightly
different avenue: manipulating pancreatic stem cells to become
insulin-producing islet cells. Stem cells are one of medicine’s hottest
fields, using primitive cells that can be nudged to develop into virtually
any kind of tissue.
In this study, researchers at Ammon Peck’s laboratory at the University of
Florida in Gainesville manipulated stem cells from the pancreases of eight
mice with diabetes, grew them in the lab, then implanted them back into the
mice, on a section of the kidney.
Mice didn’t need insulin…
Five days after the implantation, Peck and his colleagues weaned the mice
off insulin. Within one week, the mice’s average blood sugar levels had
dropped from 400 milligrams per deciliter to between 180 and 220.
The mice appeared healthy and no longer required insulin. Blood sugar levels
in a control group of eight nonimplanted mice rose to an average of 400 to
800 milligrams per deciliter and all eight died of diabetes-related
complications.
Peck was concerned that the new islet cells would be rejected by the mice’s
immune systems. He implanted experimental cells alone under the skin of
another diabetic mouse, and implanted two other mice with cells surrounded
by a protective capsule. There was no immune reaction.
When new blood vessels reached the implants roughly seven to 10 days later,
he says, it coincided with the stabilization of blood sugar. This suggested
that once the vessels are in place, "the [islet] cells can sense changes in
the need for the amount of insulin to be secreted."
Twenty-six days after the mice were weaned off insulin, one of the mice with
the protective capsule developed fatal low blood sugar, which Peck assumed
was from the islets producing too much insulin.
In an accompanying commentary, associate professor of medicine Susan
Bonner-Weir of the Harvard School of Medicine says that while the study is
encouraging, it still has problems — not the least of which being the small
number of animals involved.
She adds, "to really show that it was because of the tissue they put it,
they really should have removed that tissue and seen that the mouse became
diabetic again. That’s sort of the gold standard."
Peck says that autopsies of the mice revealed that diabetes had
destroyed their entire natural pancreas, suggesting that only the
implant could have been producing the insulin to control their diabetes.
But why the new islet cells weren’t attacked is not understood, says Peck.
Bonner-Weir says the work "is representative of a whole field that is just
coming to the forefront. That’s what’s exciting, that there may be some real
progress made."