The Promise of the Artificial Pancreas

It is, perhaps, the most exciting development in the field of type 1 diabetes since the discovery of insulin in 1921. And while not a cure for the insidious disease, the artificial pancreas (also known as bionic pancreas) has the potential to be a genuine game changer.

Currently under development in locations across the globe, this breakthrough in blood sugar management isn’t actually an organ, but rather a system that allows existing devices to communicate with one another and dispense insulin automatically using real-time data, thereby keeping blood glucose (blood sugar) levels as close to normal as possible and mitigating short- and long-term complications caused by the disease. In short, it does the work a healthy pancreas would do.

At present, the full burden of diabetes self-management falls on the patient, or a parent if the patient is young. He or she has to calculate appropriate insulin doses based on what they eat, their physical activity, blood glucose levels and other factors – all of which require a great deal of physical, mental and emotional attention. For women, menstrual and pregnancy hormones are added factors that affect blood sugar and need to be considered.

Even with meticulous attention to the details, this approach can only approximate the real-time blood glucose control that comes from having a normal pancreas and leaves the patient at risk for complications, among them diabetic kidney disease (nephropathy), diabetic eye disease (retinopathy), diabetic nerve disease (neuropathy), heart attack, stroke, and peripheral vascular disease hardening of the arteries). Plus, insulin therapy makes dangerously low blood glucose levels (hypoglycemia) more likely as well, which can lead to unconsciousness or even death in its severest forms.

By automating detection of blood sugar levels and delivery of insulin in response to those levels, an artificial pancreas has the potential to relieve the person with diabetes from some of this burden, providing optimal blood glucose control with minimal effort and reducing the potential for disease complications.

There are two types of artificial pancreas systems currently under development. The first, a “closed loop delivery system,” includes devices already familiar to many people with diabetes: an insulin infusion pump and a continuous glucose monitoring system (CGM), as well as a third device that acts as the “brains” of the system. The pump is a small computerized device that delivers insulin continuously through a small plastic tubing (catheter) inserted beneath the skin. The CGM is a tool that measures glucose levels in real time throughout the day and night via a tiny electrode called a glucose sensor. Also inserted beneath the skin, the glucose monitor sends data to an external monitoring and display device.

The external device – comparable to a smart phone – uses wireless Bluetooth technology to interpret the blood glucose values from the glucose sensor and communicate them to the insulin pump in order for the pump to adjust the insulin delivery rate and keep blood glucose levels within a target range. The closed loop refers to the continuous cycle of feedback information from the glucose sensor through the external device to the insulin pump. This newer, automated technology removes much of the guesswork and calculations normally carried out by the patient, although a person using the artificial pancreas would have the option of making dosing adjustments in certain situations.

Despite its promise, progress with this insulin pump-continuous glucose monitor system has been slow due to inaccuracies in CGM readings, problems with the way some types of insulin are absorbed by the body, and challenges with adjusting insulin based on CGM readings. Plus, it still requires that the person make the decision of how much insulin to administer rather than this happening automatically.

The second system is being developed by a collaborative group from Boston University and Massachusetts General Hospital. The primary difference with this system, called a dual-hormone system, is the addition of man-made glucagon to the rapid-acting insulin. Glucagon is a synthetic version of human glucagon, which is a hormone produced by the pancreas that works in tandem with insulin to control the level of glucose in the blood. Glucagon’s purpose is to counteract low blood sugar (hypoglycemia) episodes. As directed by a computer algorithm, the glucagon in this system is delivered to the body via a second pump when it detects low blood sugar. This system automatically makes a new decision about insulin and glucagon dosing every five minutes -- that’s 288 decisions per day, 7 days per week, 365 days per year.

While advantages of the artificial pancreas are numerous, the technology comes with disadvantages as well. A continuous glucose monitor measures glucose level in the tissue fluid, which does not change as quickly as the glucose level in the blood, which can lead to inappropriate dosing of insulin when the blood glucose is too high or too low. Patients would need to carry an additional device (the “brain”). And it’s currently only available for clinical trials.

Although the biomedical creation is far from perfect and a number of issues need to be resolved before an artificial pancreas is presented to the public, these issues are constantly being worked on. Just like artificial limbs or hearts before it, and regardless of its present imperfections, there’s no doubt the artificial pancreas has the potential to give a new lease on life to millions of people suffering from type 1 diabetes.img src="/sites/all/images/empower-smlogo.png"/>

Dr. Nirali Shah is a current second-year Fellow in the Division of Endocrinology, Diabetes and Bone Disease at the Icahn School of Medicine at Mount Sinai in New York City . She received her medical degree from Smt. N.H.L Municipal Medical College, India and completed her internal medicine training at Stony Brook University Hospital in New York, where she also served as chief resident. She is currently board certified in Internal Medicine.

Dr. Erika Villanueva is a second-year Fellow in the Division of Endocrinology, Diabetes and Bone Disease at the Icahn School of Medicine at Mount Sinai, New York City. She received her medical degree from the University of Medicine and Dentistry of New Jersey and completed her internal medicine training at Jefferson University Hospital in Philadelphia, Pennsylvania. She is currently board certified in Internal Medicine.