Artificial Pancreas on the Horizon
An artificial pancreas could revolutionize the treatment of diabetes, and it may only be a few years away.
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 Laboratory, agrees.
"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.
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 deliver.
"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."