UC San Diego researchers develop implantable glucose sensor that lasts for a year in pigs

UC San Diego researchers have developed an implantable glucose sensor for diabetics that has worked for a year in pigs and that could be a major step forward toward the development of an artificial pancreas. As many as 800,000 people already use external insulin pumps that, through programming, inject a continuous background level of insulin and higher jolts at mealtimes or when a physical blood test indicates. The goal of many researchers has been to develop a continuous glucose monitor that can be implanted and send electronic signals to control how much insulin the pump secretes, thereby mimicking the action of the pancreas. Despite widespread efforts, however, that goal has proved elusive.

Bioengineer David Gough of UC San Diego and his colleagues have developed a sensor that uses two continuous oxygen monitors. In a small chamber in the device, glucose from the blood is oxidized and the device measures the oxygen that is left behind. A second sensor measures the amount of oxygen in the blood. By subtracting the two readings, the device can tell how much glucose is in the blood. It then transmits the reading to a receiver that must be within 10 to 12 feet of the patient.

Gough reported Wednesday in the journal Science Translational Medicine that they had implanted the device, which is about 1.5 inches in diameter and 5/8 of an inch thick, into two pigs, where it operated successfully for a year in one and for 10 months in the other. Gough said he hopes to begin clinical trials in humans within a year. If the device is eventually approved, he said, its first uses would probably be as a simple monitor. Current practice for diabetics involves finger sticks about four times per day to monitor blood sugar, but wide swings in sugar levels can occur between measurements. Those swings are responsible for many of the complications of diabetes. Parents of diabetics, moreover, typically worry about sugar levels in their children during the night, frequently waking them up to take readings. The new device could broadcast an alert if levels got too low or too high.

Gough is the founder of a San Diego company, GlySens Inc. that is developing the sensor. Funding for his studies has been provided by the company, the National Institutes of Health and the Juvenile Diabetes Research Foundation.

-- Thomas H. Maugh II