Pro-humanist f 2015-12-08 16:30:04
Type 1 diabetes research news:
Feb. 25, 2004
Embryonic Pig Cell Transplants Halt Rat Diabetes
An experimental cross-species transplant to treat diabetes
has passed an early test in rats with better-than-expected
results, suggesting the innovative approach might halt type 1
diabetes while greatly reducing the risk of rejection.
Scientists at Washington University School of Medicine in
St. Louis set up control and experimental groups of rats with
diabetes. The experimental group received embryonic pig
pancreas cell transplants and antirejection drugs to prevent
the rats’ immune systems from destroying the transplants.
The control group received only the transplants and no im-
mune suppression drugs. To the researchers’ surprise, the
control group’s transplants grew unmolested by the immune
system, halting the rats’ diabetes and changing the focus of
the study to transplanting without the need for immune sup-
“Every once in a while you get lucky, and now we have the
possibility of transplanting these pig cells and not having to
worry about rejection,” says Marc R. Hammerman, M.D.
… Hammerman, an endocrinologist and director of the Renal
Division, is a leader in the emerging field of organogenesis,
which is focused on growing organs from stem cells and other
embryonic cell clusters known as organ primordia. Unlike stem
cells, primordia cannot develop into any cell type — they are
locked into becoming a particular cell type or one of a partic-
ular set of cell types that make up an organ.
In multiple groups of diabetic rats that were unable to pro-
duce their own rat insulin, Hammerman and Sharon Rogers,
research instructor in medicine, transplanted pig pancreas
primordia into the omentum, a membrane that envelops the
intestines and other digestive organs. Within two weeks, the
primordia engrafted and began producing pig insulin.
The pig insulin replaced the missing rat insulin, returning the
rats’ blood glucose to normal levels, an effect that continued
for the rest of their lives.
Hammerman had theorized for years that implanting primordia
obtained very soon after organ formation and coaxing the cells
into growing into fully functioning organs inside a transplant
recipient might reduce immune system rejection. However, he
admits he is stunned by the new success.
“Conditions that are permissive for transplantation from one
species to another frequently don’t translate to transplants into
another species,” Hammerman says. “But this dramatic elimin-
ation of the need for immune suppression is quite unusual;
there’s not a lot of precedent in the literature for it. So it’s pos-
sible that it may also apply in other cross-species transplants
and maybe even in pig-to-human transplants.”
Diabetes in humans is sometimes treated by transplanting
human insulin-producing pancreas cells known as the islets of
Langerhans. According to Hammerman, using embryonic pig
cells as the transplant source instead of human islets circum-
vents three major difficulties.
“First, there aren’t nearly enough human pancreas organs to
go around,” Hammerman says. “Since pig insulin works fine in
humans, if pigs could be used as donors the shortage would
Second, islets can only be extracted from the pancreas by
mincing the organ and exposing it to enzymes that break down
“This damages islets,” Hammerman says. “So not all of the
transplanted islets engraft, and many that do engraft die after
a period of time.”
Third, islets are composed of mature cells unable to respond
to increased need for their services by dividing and producing
more cells. In contrast, embryonic pancreas cells divide readily
in response to such needs, resulting in a potentially expandable
source of insulin.
For reasons not yet understood, the transplanted pancreas cells
did not develop an additional digestive function normally asso-
ciated with the pancreas.
“That was another remarkably lucky break,” Hammerman notes,
“because only the endocrine cells are required to treat diabetes.
The digestive cells would have only caused problems.”
If elimination or reduction of immune rejection transfers to pig-to-
human transplants, the technique will defeat or greatly diminish
a final formidable obstacle to treating diabetes with transplants.
“Immunosuppressing a patient introduces a whole new set of dan-
gers and side effects,” says Hammerman. “Patients with type 1
diabetes have to ask themselves, would I rather take insulin, or
would I rather take all these immunosuppressive drugs? It’s not
the greatest choice in the world.”
The next phase of research will involve pig-to-primate transplants.
If those are successful, then pig-to-human transplant trials can be
Hammerman also is studying the use of kidney primordia from
embryonic pigs to grow new kidneys inside recipients as a treat-
ment for end-stage kidney failure.
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Beav 2015-12-08 16:30:15
Verrrrry interethting. (really)