Living with type 1 diabetes can be challenging, to say the least. Sufferers have the arduous task of attempting to maintain their blood sugar levels daily with insulin injections and fingerprick tests, which often amounts to guesswork. But scientists around the world are endeavoring to develop new ways to manage the condition, such as non-invasive skin patches that constantly monitor glucose levels for you.

And now, approaching the problem from a different angle, researchers may have come up with another way to eliminate the need to regularly check blood sugar throughout the day with the development of a “smart insulin” that automatically activates when glucose levels are too high. The new compound, which appears to be effective in mice, also sticks around in the blood for up to 24 hours, raising the possibility that in the future, patients would only need a daily injection.

Type 1 diabetes is a condition that arises from the body’s self-destruction of insulin-producing cells in the pancreas. The job of insulin is to stimulate our tissues to mop up excess glucose from the blood, so in its absence, blood sugar levels can become dangerously high. That’s why diabetes patients monitor their carbohydrate intake and glucose levels and repeatedly inject insulin based on these numbers. Long-acting insulin, which lasts for around 24 hours, can also be used, but with both short- and long-acting forms patients can end up with too much in their blood, which leads to potentially fatal low blood glucose, or hypoglycemia.

Patients can also not inject enough into their blood, which results in high blood glucose, or hyperglycemia. As pointed out by The Guardian, if this occurs regularly, serious long-term complications can ensue, such as blindness and nerve damage. The idea behind the new insulin is to eliminate these glucose problems, which its developers say is theoretically achievable, by creating a long-lasting version that only becomes activated when needed.

The new compound, which is described in Proceedings of the National Academy of Sciences, was developed by researchers at MIT and the University of Utah. To make their glucose-responsive insulin, they started off by adding a molecular switch consisting of a chain of fatty molecules. This makes the insulin hang around the blood for extended periods, possibly by attaching it to a blood protein so that it’s not free to cling onto sugar.

Next, they added a further molecule called PBA which reversibly binds to glucose, meaning that it can also let go. When a particular blood glucose threshold is reached, the modified insulin becomes released and binds to the sugar, triggering events which result in cells taking up the excess glucose.

So far, the insulin has only been scrutinized in mice, but the results are promising. Diabetic mice given a single daily injection of the modified hormone had glucose levels comparable to those of healthy mice, and it was found to be better at controlling blood sugar after simulated meals than unmodified insulin or long-acting insulin. While this study was certainly encouraging, unfortunately years of further animal tests to prove its safety and efficacy will be required before it can progress to human trials. Still, it’s certainly a step in the right direction, and hopefully it can eventually make the lives of many diabetics easier.

[Via PNAS, MIT and The Guardian]