Artificial Pancreas on the Horizon
An artificial pancreas could revolutionize the treatment of diabetes, and it may only be a few years away.
Smart System a Major Milestone
Other research is focusing on improving communication between
the glucose sensor and the external insulin pump. According to Joseph, a major
milestone was reached this summer when the FDA approved one of the first smart
systems that allows the two systems to communicate via a wireless
Such systems take a lot of the guesswork out of insulin dosing,
Traditionally, patients had to prick their fingers and place
the blood on a strip to get a blood sugar reading, estimate how many grams of
carbohydrates they planned to eat, and mentally calculate how much insulin they
needed. The system left much room for error, with the wrong calculation
potentially leading to dangerously high or low blood sugar levels.
With the newly approved Paradigm system, which combines the
Medtronic MiniMed insulin pump and a glucose monitor from Becton Dickinson,
patients still prick their fingers to measure their blood sugar levels. But the
pager-sized glucose monitor transmits the information straight to the insulin
pump. The insulin pump then calculates the amount of insulin required for the
current blood sugar. By having the pump calculate the dose required, you could
prevent errors that sometimes result when patients input this data manually, he
"It's up to the patient to decide if the suggested amount
is correct and push a button to deliver the recommended dose," Joseph says.
"It's not an artificial pancreas as it's not fully automated. But it's a
major advance of convenience and has the potential to improve blood sugar
control in the clinical setting."
Measuring Blood Sugar Levels
About two dozen companies and academic labs are developing
glucose sensors, Joseph says. Some are blood glucose sensors, others are tissue
fluid glucose sensors; some are placed under the skin by the patient, others
are implanted long-term in the body.
While glucose sensors have improved significantly over the past
few years, they are still the limiting factor in making the artificial
pancreas, he says.
Steve Lane, PhD, acting program leader of the Medical
Technologies Program at the Department of Energy's Lawrence Livermore National
"Almost certainly the goal of production of an artificial
pancreas will be achieved," says Lane, whose department worked on a
prototype of the artificial pancreas in partnership with MiniMed. "But
there are obstacles to be overcome, the major one being glucose sensing. To
date, no one has developed a foolproof way of sensing glucose."
Animas Corp. is developing an implantable optical glucose
sensor. In animal and preliminary human studies, the device accurately measured
blood sugar levels in the blood using infrared optics.
"A miniature sensor head is placed around a blood vessel,
and a light source is focused through the blood to a detector," says
Joseph. "The absorption of light at specific infrared wavelengths
determines the concentration of sugar in the blood."
Further along in development are Medtronic MiniMed's short-term
and long-term implantable glucose sensors, designed to continually measure the
level of sugar in the tissue fluid or blood.