Smart artificial cells may help treat diabetes

Scientists have developed smart artificial cells that could help manage diabetes without painful and frequent injections, by automatically releasing insulin into the bloodstream when glucose levels rise.
The "artificial beta cells" (ABCs) mimic the functions of the body's natural glucose-controllers, the insulin-secreting beta cells of the pancreas.
The loss or dysfunction of these cells causes type 1 diabetes and many cases of type 2 diabetes.
The idea is that the ABCs could be subcutaneously inserted into patients, which would be replaced every few days, or by a painless and disposable skin patch.
A single injection of the ABCs into diabetic mice lacking beta cells quickly normalised the animals' blood glucose levels and kept those levels normal for up to five days.

"Our plan now is to further optimise and test these synthetic cells in larger animals, develop a skin patch delivery system for them, and ultimately test them in people with diabetes," said Zhen Gu, a professor at the University of North Carolina (UNC) in the US.

Millions of people use insulin as a diabetes treatment, either by injection or a mechanical pump.
So far, delivering insulin in pill form has been challenging because it is a large molecule that would be destroyed by digestive enzymes and acids before it could reach the bloodstream.
The major problem with current insulin treatments, however, is that they can not control blood glucose levels automatically and efficiently, as normal insulin-secreting pancreatic cells do.

Transplants of pancreatic cells can solve that problem in some cases. However, such cell transplants are expensive, require donor cells that are often in short supply, require immune-suppressing drugs, and often fail due to the destruction of the transplanted cells.
Researchers, including those from North Carolina State University (NC State), adopted a particularly ambitious approach: making artificial cells that do what natural pancreatic beta cells do.
The ABCs are constructed with a simplified version of a normal cell's two-layered lipid membrane.
The key innovation is what these cells contain: specially designed, insulin-stuffed vesicles.
A rise in blood glucose levels leads to chemical changes in the vesicle coating, causing the vesicles to start fusing with the ABC's outer membrane - thus releasing the insulin payloads.

"This is the first demonstration using such a vesicle fusion process for delivering insulin that employs insulin- containing vesicles like those found in a beta cell and can reproduce the beta cell's functions in sensing glucose and responding with insulin 'secretion'," said Zhaowei Chen, postdoctoral researcher in Gu's lab.
The ABCs showed a rapid responsiveness to excess glucose levels in lab-dish tests and in diabetic mice without beta cells.