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杂谈 |
WEDNESDAY, Jan. 27, 2016 (HealthDay News) -- Using a two-pronged
approach, researchers report they were able to restore normal blood
sugar levels for six months in mice with induced diabetes.But,
while the research is promising, it's too soon for people with type
1 diabetes to start planning a life free of needles and injections
just yet, experts said.The first part of the treatment was using
insulin-producing pancreas cells generated from human stem cells
employing a technique recently developed at Harvard. But the latest
breakthrough came from MIT researchers, who developed a way to
encapsulate the cells -- called islet cells -- before they were
implanted in the mice, to protect them from the immune
system.That's key for two reasons. One is that when you introduce
foreign cells into the body, the immune system recognizes them as
foreign and destroys them. This is why people who have organ
transplants need to take immune-suppressing medications, which can
cause serious side effects.The second reason is that type 1
diabetes develops when the body's immune system mistakenly attacks
healthy islet cells and destroys them -- known as an autoimmune
attack. When people have had islet cell transplant, the new cells
eventually die off, and researchers suspect one reason why is that
the autoimmune attack doesn't stop.However, the encapsulation hides
the islet cells, essentially making them invisible to the immune
system, the researchers explained."They're stealth islets," said
Julia Greenstein, vice president of discovery research for JDRF, a
type 1 diabetes research foundation that provided funding for the
study along with the Helmsley Charitable Trust and the U.S.
National Institutes of Health."We're really excited about this.
It's been a long and big effort for us to try to drive novel
biomaterials," she added.There are still a number of steps before a
human trial could be done, such as scaling up the capsules for
larger animals, and seeing whether or not the encapsulated islet
cells can achieve blood sugar control in non-human primates,
Greenstein said.But, if all goes well, both Greenstein and the
senior researcher on the project, Daniel Anderson, an associate
professor of chemical engineering at the Massachusetts Institute of
Technology in Cambridge, Mass., predict that phase 1 clinical
trials in people might just be a few years away.Anderson and his
colleagues initially isolated a molecule from seaweed, or brown
algae. "We then made chemical modifications that would be able to
do different things, and then we had to see which might actually
work," Anderson said.The scientists created approximately 800
seaweed derivatives, and one seemed quite promising as a material
for encapsulation. The researchers encapsulated human stem cells,
and implanted them in mice with induced type 1 diabetes. The
encapsulated cells were left in for 174 days, and then
removed.During that time, the transplanted islet cells produced
insulin and the mice were able to achieve normal blood sugar levels
without insulin injections. The mice didn't show any signs of
rejection, according to Anderson. And, when the time came, the
encapsulated cells were easy to remove.This study was only
scheduled to last six months, but Anderson said the researchers
"hope these devices could last for years."The findings were
published online Jan. 25 in
SOURCES: Julia Greenstein, Ph.D., vice president, discovery
research, JDRF; Joel Zonszein, M.D., director, Clinical Diabetes
Center, Montefiore Medical Center, New York City; Daniel Anderson,
Samuel A. Goldblith Associate Professor, chemical engineering,
Massachusetts Institute of Technology, Cambridge, Mass.; Jan. 25,
2016,
HealthDay