Biomedical engineer Edward Damiano is trying to build an artificial pancreas… (Firas H. El-Khatib, Boston…)
Every night, Edward Damiano wakes three to four times to monitor his 11-year-old son's blood sugar levels. Damiano administers insulin remotely through a pump when his son's blood sugar reading is high or gives him juice through a straw when his blood sugar falls.
His son, David, who was diagnosed with Type 1 diabetes at 11 months old, sleeps peacefully through it all — and that's exactly what worries Damiano.
"You can check his blood sugar all night long and he won't wake up," Damiano says. "Right now it's a blessing. But when he goes to college, this is scary to me. I'm not going to be there."
Damiano, a biomedical engineer at Boston University, is trying to build an artificial pancreas that could help people with Type 1 diabetes maintain healthy levels of glucose in the blood by the time his son leaves for college.
The device he's working on, intended to mimic the exquisite sensitivity of the pancreas, relies on a computer algorithm that acts like a "brain" to calculate the precise dosage of two hormones, insulin and glucagon, that are needed at any one time. The software is sandwiched between existing technologies — a sensor that reads blood sugar every few minutes and a pump that administers the insulin and glucagon — with which the computer "talks" to dictate dosing.
"It's mathematical; it's objective," said Firas El-Khatib, a biomedical research scientist at Boston University who has worked with Damiano since the beginning on the control algorithms. "It takes the human out of the loop."
Around the world, roughly a dozen groups are testing similar technologies. Damiano's team, further along than most, began testing its computer algorithm in humans in 2008 and is in its second round of in-patient human trials. Damiano says he hopes to be performing out-patient trials by 2012 and estimates that the device could be on the market by 2015.
Under normal conditions, levels of glucose in the blood are kept under tight control by insulin and glucagon: Insulin orchestrates the uptake of glucose by cells for use as energy, and glucagon counteracts that effect when blood sugar gets too low by helping the body access stored glucose from the liver.
But in Type 1 diabetes, the insulin-producing cells of the pancreas, known as beta cells, are destroyed by the immune system and can no longer produce the insulin, leaving the cells that produce glucagon to operate in the dark.
Damiano is convinced that the best artificial pancreas should incorporate both hormones — insulin for when blood sugar climbs too high and glucagon for when it falls too low.
One of the hitches, however, is that glucagon is not yet approved by the Food and Drug Administration for long-term use because it breaks down in solution. Several companies are tackling that problem. In the meantime, since a system that uses only insulin is likely to be FDA-approved sooner, Damiano's team is working on an insulin-only system as well.
It is a common misconception that diabetes is fairly well managed with a few routine insulin injections throughout the day. In fact, maintaining healthy blood sugar levels — a life-or-death matter — is surprisingly difficult, and very few people with diabetes are able to do it effectively. The process is time-consuming and requires constant vigilance. And even those who monitor rigorously in some cases struggle with erratic blood sugar levels.
"The current treatments we have, although much better than they were, are really not solving the problem for the majority of people with Type 1 diabetes," says Dr. Gordon Weir, a diabetes researcher at the Joslin Diabetes Center and professor of medicine at Harvard Medical School, who is not involved with Damiano's research. "With current insulin treatment, we very rarely bring the sugar levels into the normal range. I think most, the majority, are in a range where damage is occurring."
One of the challenges is that people with Type 1 diabetes walk a fine line between the immediate risks of hypoglycemia (low blood sugar) and the longer-term risks of hyperglycemia (high blood sugar). Even a slight overdose of insulin can cause a precipitous drop in blood sugar, leading to sweating, trembling and confusion — and, if the situation persists, to loss of consciousness, seizures, even death.
Since low blood sugar is life-threatening, many people with diabetes tend to be conservative and allow their blood sugar to remain on the high end. But elevated blood sugar for prolonged periods causes insidious damage to the nerves, kidneys, eyes and heart. Diabetes is the leading cause of blindness, kidney failure and amputations, and it dramatically increases the risk of heart disease.