This is very surprising and could
well lead to an effective way to treat Diabetes I certainly and perhaps
Diabetes II. The idea that a drug
pathway could exist that stimulate gut based insulin production that works the
same way as the pancreas is a complete surprise and could well provide a
permanent solution to the global epidemic of this disease.
One wonders if other applications
may exist in the conversion of specific gut cells to necessary hormone production
now we know it is even a possibility.
It is far too early to be other
than slightly optimistic and will keep an eye out for further developments.
New Approach to Treating Type 1 Diabetes? Transforming Gut Cells Into
Insulin Factories
ScienceDaily (Mar. 11, 2012) — A study by Columbia researchers
suggests that cells in the patient's intestine could be coaxed into making
insulin, circumventing the need for a stem cell transplant. Until now, stem
cell transplants have been seen by many researchers as the ideal way to replace
cells lost in type I diabetes and to free patients from insulin injections.
The research -- conducted in mice -- was published 11 March 2012 in the
journal Nature Genetics.
Type I diabetes is an autoimmune disease that destroys
insulin-producing cells in the pancreas. The pancreas cannot replace these
cells, so once they are lost, people with type I diabetes must inject
themselves with insulin to control their blood glucose. Blood glucose that is
too high or too low can be life threatening, and patients must monitor their
glucose several times a day.
A longstanding goal of type I diabetes research is to replace lost
cells with new cells that release insulin into the bloodstream as needed. Though
researchers can make insulin-producing cells in the laboratory from embryonic
stem cells, such cells are not yet appropriate for transplant because they do
not release insulin appropriately in response to glucose levels. If these cells
were introduced into a patient, insulin would be secreted when not needed,
potentially causing fatal hypoglycemia.
The study, conducted by Chutima Talchai, PhD, and Domenico Accili, MD,
professor of medicine at Columbia University Medical Center, shows that
certain progenitor cells in the intestine of mice have the surprising ability
to make insulin-producing cells. Dr. Talchai is a postdoctoral fellow in
Dr. Accili's lab.
The gastrointestinal progenitor cells are normally responsible for
producing a wide range of cells, including cells that produce serotonin,
gastric inhibitory peptide, and other hormones secreted into the GI tract and
bloodstream.
Drs. Talchai and Accili found that when they turned off a gene known to
play a role in cell fate decisions -- Foxo1 -- the progenitor cells also
generated insulin-producing cells. More cells were generated when Foxo1 was
turned off early in development, but insulin-producing cells were also
generated when the gene was turned off after the mice had reached adulthood. "Our
results show that it could be possible to regrow insulin-producing cells in the
GI tracts of our pediatric and adult patients," Dr. Accili says.
"Nobody would have predicted this result," Dr. Accili adds.
"Many things could have happened after we knocked out Foxo1. In the
pancreas, when we knock out Foxo1, nothing happens. So why does something
happen in the gut? Why don't we get a cell that produces some other hormone? We
don't yet know."
Insulin-producing cells in the gut would be hazardous if they did
not release insulin in response to blood glucose levels. But the researchers
say that the new intestinal cells have glucose-sensing receptors and do exactly
that.
The insulin made by the gut cells also was released into the
bloodstream, worked as well as normal insulin, and was made in sufficient
quantity to nearly normalize blood glucose levels in otherwise diabetic mice.
"All these findings make us think that coaxing a patient's gut to
make insulin-producing cells would be a better way to treat diabetes than
therapies based on embryonic or iPS stem cells," Dr. Accili says. The
location of the cells in the gut may also prevent the diabetes from destroying
the new insulin-producing cells, since the gastrointestinal tract is partly
protected from attack by the immune system.
The key to turning the finding into a viable therapy, Dr. Accili says,
will be to find a drug that has the same effect on the gastrointestinal
progenitor cells in people as knocking out the Foxo1 gene does in mice. That
should be possible, he says, since the researchers found that they could also
create insulin-producing cells from progenitor cells by inhibiting Foxo1 with a
chemical.
"It's important to realize that a new treatment for type I
diabetes needs to be just as safe as, and more effective than, insulin,"
Dr. Accili says. "We can't test treatments that are risky just to remove
the burden of daily injections. Insulin is not simple or perfect, but it works
and it is safe."
The research was supported by the NIH (DK58282, DK64819, DK63608), the New York Stem Cell
Foundation, and the Russell Berrie Foundation.
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