Researchers Design Synthetic Beta Cells to Secrete Insulin in Response to High Blood Sugar

Source: University of North Carolina Health Care

Summary: Researchers have developed smart artificial beta cells which are capable of releasing insulin automatically into the bloodstream whenever there is a rise in the blood glucose.

Treatment for Type 1 diabetes and few cases Type 2 diabetes requires a painful and frequent insulin injections or an insulin pump for the infusion of insulin. Researchers at the University of North Carolina Health Care have developed a much more patient-friendly option – the smart artificial beta cells which are capable of releasing insulin automatically into the bloodstream whenever there is a rise in the blood glucose. These artificial beta cells (AβCs) mimic the natural insulin-secreting beta cells of the pancreas. The loss of these natural beta cells leads to Type 1 diabetes and some cases of Type 2 diabetes. The idea is to insert ACs subcutaneously by a painless and disposable skin patch. The work was published in the journal Nature Chemical Biology.

Insulin secreting cells

Fluorescence image of the artificial beta cells. Credit: Gu Lab, UNC-NC State

The study was conducted in mice, by injecting a single dose of AβCs into diabetic mice which lacked beta cells, quickly normalized the blood glucose levels and the levels were normal up to 5 days. Almost 6 million people in the US use insulin for diabetic treatment either by injection or a mechanical pump. Insulin in pill form has been challenging as its a large molecule and can easily be destroyed by digestive enzymes and acid before it reaches the bloodstream. Pancreatic cell transplantation can solve the problem in some cases but they are expensive and even require donor cells which are often in short supply.

Researchers constructed these AβCs in a very simplified manner as a normal cell’s two-layered lipid membrane. The innovation in these cells is that they contain a specially designed insulin-stuffed vesicle. The rise in blood glucose leads to chemical changes in insulin vesicle coating and causes the vesicles to fuse with AβCs outer membrane and thus slowly releases the insulin payloads. Researchers are also working separately on a cell-free skin patch, a “smart insulin patch” which senses blood glucose and secretes insulin into the bloodstream whenever needed.

Zhaowei Chen, lead author said, “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’.”

John Buse, co-author said, “There is still much work needed to optimize this artificial-cell approach before human studies are attempted, but these results so far are a remarkable, creative first step to a new way to solve the diabetes problem using chemical engineering as opposed to mechanical pumps or living transplants.”

More Information: Zhaowei Chen et al, “Synthetic beta cells for fusion-mediated dynamic insulin secretion”, Nature Chemical Biology (2017). DOI: 10.1038/nchembio.2511

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