Artificial Pancreas on the Horizon
An artificial pancreas could revolutionize the treatment of diabetes, and it may only be a few years away.
First Artificial Pancreas Tested
In France, Renard is leading the first clinical trial of an
artificial pancreas -- a fully automated system that combines Medtronic
MiniMed's long-term glucose sensor and its implantable insulin pump.
In a minor surgical procedure, the implantable sensor is
inserted into a neck vein leading to the heart. The sensor is connected, via an
electrical-type wire under the skin, to the implantable insulin pump: As blood
sugar levels fluctuate, a signal tells the pump how much insulin to
"The patient doesn't have to do anything," Renard says.
"It's all automatic. Even if you're eating a high-carb meal, the sensor
will give the appropriate signal to deliver more insulin."
Renard says data from the first five patients who used the
device for at least six months show the sensor accurately measured glucose in
95% of cases when compared with values obtained by fingersticks.
"Our goal was to reach 90% accuracy, so this is very
accurate," he says.
More importantly, blood sugar levels were maintained in the
normal range more than 50% of the time in the patients using the pump connected
to the sensor, compared with about 25% of the time for the patient using
fingerstick values to tune insulin delivery from the implantable pump.
Also, the risk of blood sugar plummeting, known as
hypoglycemia, to dangerously low levels -- a possibility whenever extra insulin
is delivered -- dropped to less than 5%, Renard says.
Among the next steps, he says, is to make the sensor more
durable so it only has to be changed every two or three years. While
implantable insulin pumps work for an average of eight years before they have
to be changed, the sensors stop working after an average of nine months, he
Nevertheless, Renard see this as an easy hurdle to overcome.
"We will just use a different material and make it stronger," he
But Joseph says this may present a formidable challenge:
"Many years of research [show that] sensors tend to fail within months
rather than years due to the harsh environment of the body."
The mathematical programs that calculate just how much insulin
should be delivered at different parts of the day also needs to be refined,
Renard says. "Right now, the insulin pump allows a diabetic to spend about
half of his day in normal glycemia, just like a non-diabetic. But that means
that he is not in control the other 50%, which is a bit too high."
But again, he says, this is an easy problem to solve. "The
major problem is to have the accurate sensor, and we have it now. Within two
years we should have one that works longer and better, and after that, it will
be clinically available."