Robotic Pancreas for Diabetes

Driven by his 7-year-old son’s daily blood sugar tests and insulin injections to counter type 1 diabetes, the co-founder of internet sites CitySearch and Overture (formerly GoTo), Jeffrey Brewer, has taken a new approach to the insulin pump approved in the 1970s to automate the procedure for diabetics who require manual pancreatic control. Type 1 diabetes, sometimes referred to as juvenile diabetes because of its sudden onset in children, is an autoimmune disorder in which the pancreas is the target of the body’s immune cells. The pancreas is the gland responsible for releasing the hormone insulin in response to blood sugar (or blood glucose) levels. The insulin – blood glucose cycle is a constant process to use ingested sugars as energy. Disruption of this system can have severe, and sometimes fatal, consequences.

Hypoglycemia, blood sugar levels that are too low, can occur in diabetics because the pancreas also makes glucagon, a hormone responsible for releasing stored glucose into the blood. Combined with the insulin type 1 diabetics take to control their blood sugar levels (or even some type 2 diabetics), once the level falls, they cannot easily recover, making them particularly susceptible to hypoglycemia. Low blood sugar levels can be treated quickly by eating something, particularly something high in simple sugars, but it comes on suddenly. If nothing is at hand, the condition can worsen to confusion, fatigue, fainting, coma, seizures, and even death.

Hyperglycemia, blood sugar levels that are too high, occur if there is not enough insulin to counter the glucose that has been ingested. This is the condition of diabetics all over the world, and why timely insulin injections of an appropriate dose for the current blood sugar level is important in type 1 diabetics who lack a functioning pancreas. Untreated high blood glucose levels can result in ketoacidosis, which is also known as diabetic coma. When the body cannot break down glucose for energy, it begins to break downs fats, resulting in an accumulation of ketones in the blood. This condition can lead to death.

For decades, type 1 diabetics have lived with a rough calculation of how much insulin to take based on their blood glucose level, which is measured by pricking the finger (or other body parts for newer meters) to obtain a small blood sample, which is then read by a digital glucose meter. Having the disease requires multiple daily pricks, measures, and injections, a tireless attempt to stay ahead of the hyperglycemia, sometimes resulting in hypoglycemia.  Brewer’s solution for this manual approach is a robotic pancreas that measures blood glucose levels and secretes the appropriate amount of insulin on a constant basis – much like a real pancreas does.

Two steps of this process were already in place when Brewer set out to solve the problem of his son’s daily routine. One has been in place since the 1970s, an insulin pump that can be surgically placed and controlled externally as an alternative to daily injections. The other, a continuous glucose monitor, a sensor that can be placed under the skin to monitor glucose levels to avoid pricks and meter measures, was first approved in 2006, with another in 2008, and additional about to hit the market (see ChildrenWithDiabetes for recommendations and specifics).  The challenge for Brewer was the software that would connect and maintain the communication between the two types of devices. Something that others have been cautious to approach because of the liability involved if anything were to go wrong. At any given time, that connection would be the life or death decision for the person using them.

Work on such a connection began at Yale in 2008 with 17 teenagers who volunteered to pilot test the devices to compare them to blood sugar maintenance under manual control. The computer was much better at it. For a research group at the University of Virginia, the FDA allowed a waiver of animal studies for computer simulations to further test the combination device. In April 2009, the largest clinical trial of the device began with the University of Virginia group and groups in France and Italy. Two months later, Medtronic obtained approval to market such a device in some European countries. The robotic pancreas is not yet approved in the U.S. as the FDA awaits further research results on the device’s shutoff feature – something that has left Brewer and some type 1 diabetes patients upset with the agency.

For more on Jeffrey Brewer’s quest for a robotic pancreas, see Wired.