latte coffee
© Chevanon Wonganuchitmetha/EyeEm/GettyCaffeine can trigger engineered cells to release insulin.
A cup of coffee after a meal might be enough to keep diabetes under control, thanks to cells that have been engineered to release insulin when they detect caffeine.

Diabetes develops when the body loses its ability to regulate glucose levels in the blood. Some people manage this by taking frequent pin prick samples to measure their blood sugar levels, and using this information to adjust the supply of insulin from a pump worn against the skin.

Meal times are an especially taxing event, as the amount of sugar consumed must be estimated, and an appropriate dose of insulin scheduled. To get around this, Martin Fussenegger, a biotechnologist at ETH Zurich, Switzerland, and his colleagues have developed an alternative that's powered by coffee.

The team took human kidney cells and engineered them to produce insulin. They also added a receptor that would trigger the release of this insulin when caffeine was present.

Caffeine control

They then implanted these cells into 10 diabetic mice, and gave them coffee with their meals. Tests revealed this was enough to enable the mice to control their blood sugar levels as well as non-diabetic mice.

The risk of accidentally triggering a dose of insulin appears to be small. "To my knowledge there are no other significant sources of caffeine in food," says Fussenegger. "Even very small trace amounts of caffeine will not trigger the system."

Journal reference: Nature Communications, DOI: 10.1038/s41467-018-04744-1