Whether or not it ever leads
to any specific application in human beings, the recent announcement in
Science of a new technique for delivering insulin highlights the sort
of medical technologies that widespread genetic engineering is going to
unleash.
Researchers at Ariad Pharmaceuticals
in Cambridge, Massachusetts genetically engineered cells to produce insulin
along side a protein that causes the insulin to clump up together within
the cell. The insulin is thus trapped in the cell as it is too large to
pass through the cell wall.
The cells were then injected
into the muscles of diabetic mice and then fed a drug that causes the
clumping protein to split apart which releases the insulin and thereby
lowered the glucose level of the mice. Tim Clackson, the senior author
of the study published in Science, told the Associated Press, “The insulin
stays in the compartments of the cell and has no toxicity or adverse effects.
It just sits there. Only when the animal receives the drug do the aggregates
break apart and then flow into the circulation.”
The result — a potentially
needle free treatment for diabetes, and possibly a whole host of other
illnesses. Dr. Harvey Berger,Ariad Pharmaceuticals’ CEO, suggested the
technology could have broader application such as managing chronic pain,
with the cells engineered to produce and release endorphins on cue rather
than insulin. Another possibility would be for using the technique to
treat conditions which required regular, periodic release of some protein,
such as growth hormone.
Ariad Pharmaceuticals hopes
to begin human trials of this fascinating technology by 2003.
References:
Researchers
find new way to deliver insulin in lab studies. Associated Press,
February 4, 2000.
Gene therapy
may replace insulin shots in diabetics. Reuters, February 4, 2000.