Spud gun targets disease

Stephen Pincock — Fri, 25 Jul 1997 23:00:00 +0000

BY TINKERING with the genetic make-up of potatoes, Canadian researchers may
have discovered a painless way to prevent people developing diabetes. Their
genetically engineered potatoes can protect mice from the onset of a form of
diabetes known as type 1.

Type 1 diabetes develops when the body’s immune system mistakenly attacks
proteins including one called GAD on certain cells in the pancreas. These cells,
called eyelet cells, produce insulin, which is essential for maintaining correct
levels of sugar in the blood. Once they are destroyed, regular insulin
injections are the only way to avoid serious illness.

�Ӱ�ԭ��s have been looking for a way to treat the disease by stopping the
immune system from killing eyelet cells. Many studies have focused on the idea
of oral tolerance—that regularly eating large amounts of GAD could prevent
the immune system from attacking the protein. The problem has been that it is
difficult to manufacture GAD in bulk.

A team of researchers led by Anthony Jevnikar of the University of Western
Ontario believe they have the answer. They inserted the gene that codes for GAD
into the DNA of potato plants, which grew to produce potatoes with high levels
of GAD. For several months, the team fed these potatoes to mice that had been
specially bred to be highly susceptible to diabetes. “These mice are a good
model of what happens in type 1 diabetic people,” says Jevnikar. “They have the
same pancreas structure and immune response.”

In this month’s Nature Medicine (vol 3, p 793), the team reports
that only 2 of the 12 mice fed with the potatoes developed the disease, compared
with 8 out of 10 untreated control mice. “Our ultimate goal is to see if this
method will work in humans,” says Jevnikar.

“This is an important combination of two new technologies—oral
tolerance and genetic manipulation,” says Marco Londei, an expert in the
immunology of diabetes at the Kennedy Institute of Rheumatology in London. “If
the approach does transfer into humans, I could imagine it being useful for
treating children—they wouldn’t know they were eating medicine.”

Jevnikar suggests that genetically altered plants could also be used to treat
a variety of autoimmune diseases such as multiple sclerosis and rheumatoid
arthritis. “I have a feeling this could be the first of many similar approaches
to treating disease,” he says. “Inducing oral tolerance by eating genetically
engineered plants could even prevent rejection of transplanted organs.”

Stephen Pincock, Author at New �Ӱ�ԭ��

Spud gun targets disease