Patients with type 1 diabetes (T1D) are forced to spend much of their time obsessing about their blood sugar and insulin doses. The state of the art in treatment of T1D is an insulin pump that delivers insulin and a continuous glucose monitor that displays the glucose level and sounds alarms for values that are too low or too high. (See here for a refresher on the differences between type 1 and type 2 diabetes.)
Currently, patients have to evaluate the readings of the glucose monitor, calculate the appropriate doses of insulin for every meal, make mental adjustments for exercise, physical or emotional stress, or acute illness, and enter the appropriate dose into the insulin pump. This is a very inexact art. Too much insulin leads to low blood sugars which can be life threatening. Too little insulin keeps blood sugars too high which will result in complications decades later.
In people without diabetes, the pancreas regulates blood sugar levels automatically by regulating the release of two hormones, insulin which lowers blood sugar, and glucagon which increases it. I have the luxury of eating, exercising, and suffering from the flu without ever thinking about my blood glucose. My nephew Elliott, who has T1D, would be threatening his life if he did that.
A study published this week in the New England Journal of Medicine (NEJM) brings patients with T1D a small step closer to living like the rest of us. The study tested a very preliminary attempt at an artificial pancreas in 52 adolescents and adults over a 5 day period. This bionic pancreas, as the researchers call it, consists of a continuous glucose monitor that is attached to a smart phone. The smart phone runs software that receives the glucose information from the glucose monitor and calculates the amounts of insulin and glucagon that should be delivered. The software connects via Bluetooth to two hormone pumps that deliver hormones through tubes inserted under the skin, one for insulin, and one for glucagon. The patient can interact with the software to announce that he’s about to have a meal or a snack. The software does the rest.
The study showed that the patients’ blood sugar was better controlled when they were using the bionic pancreas than during five days when they were managing their sugars themselves. Importantly, the bionic pancreas did not result in more episodes of seriously low blood sugars. And the difference in quality of life promises to be huge – no more careful counting of every carbohydrate ingested, no more calculating the appropriate insulin dose, no more obsessing about how much to compensate for 30 minutes of bike riding.
This study was small and preliminary. An artificial pancreas isn’t going to be mass marketed tomorrow. Lots of improvements still need to be made, and the entire unit needs to be consolidated into one box so that it doesn’t depend on a finicky Bluetooth connection. And then it needs to be tested on thousands of patients.
We now have machines and prostheses that do a reasonable job of replacing broken kidneys and cochleas and hip joints. This week brings promise that we are approaching a day when we’ll be able to do the same for broken pancreases.
Advances Made in Regulating Type 1 Diabetes (Wall Street Journal)
Father Devises A ‘Bionic Pancreas’ To Help Son With Diabetes (NPR Shots)
Bionic pancreas helps control diabetes, study says (USA Today)
A diabetic child spurs a race for a bionic pancreas (Bostonia)
ENG Prof’s Bionic Pancreas Takes a Big Step Forward (Boston University Biomedical Engineering News)
Outpatient Glycemic Control with a Bionic Pancreas in Type 1 Diabetes (NEJM)