Diabetes mellitus is an incurable disease in which the insulin-producing cells of the pancreas (β-cells) fail to produce sufficient amounts of insulin. Normally, the insulin hormone will be released from healthy β-cells to help metabolize the elevated blood sugar levels after a meal. But individuals with inadequately functioning β-cells cannot produce enough insulin to control blood sugar levels, leading to a number of diabetes-related complications.
The current method of treatment is a life of painful and imprecise insulin injections. If inadequate amounts of insulin are injected, blood sugar levels remain high, eventually leading to complications including blindness or kidney failure. Further more, over-injection of insulin can lead to hypoglycemia, which can lead to seizures, brain damage, behavioural changes, and sometimes even death.
There has been some success in overcoming the limitation of traditional insulin injections by using transplantation of healthy β-cells directly into the host. In principle, these healthily injected β-cells would be able to modulate the adequate concentration of insulin needed to be secreted based on their surrounding blood sugar levels, but this treatment requires extensive immunosuppressive therapy to the patient to be able to prevent rejection of the transplant. The immunosuppressants themselves can also make the patient susceptible to infections.
It is clear that we need a more effective way to control the levels of insulin being injected into diabetic patients in order to be able to better control elevated blood glucose levels.
Researchers at the University of North Carolina and North Carolina State University describe an externally applied patch, essentially applied like you would a sticker, containing β-cells that can modulate the individual’s glucose levels by secreting insulin when necessary through microneedles. This patch eliminates the need for the β-cells to interact with the host’s immune system, preventing rejection by the host.
How does it work?
The β-cells lie in capsules on the external surface of the patch and there a tiny microneedles on the internal surface that would be applied to the skin. This is regarded as a minimally invasive approach given that the needles are comparable to the thickness of a strand of hair. The needles contain “glucose-signal amplifiers” to amplify changes in glucose concentrations in the individual that are significant to induce hyperglycemia but otherwise too subtle to be detected by the β-cells without the amplifier. Once the β-cell-capsules receive this “high sugar” signal, they secrete insulin (as they would if they were functioning in a healthy individual), which is diffused into the bloodstream.
In type-1 diabetic mice, these researchers found that this patch (containing approx. 10 million β-cells) quickly responded to a hyperglycemic state (within the first two hours of application, based on their in vitro studies) and maintained homeostatic levels of blood glucose for up to 10 hours.
While this patch has not yet been tested on humans, this device is a promising alternative to pancreatic β-cell transplantation, as it reduces the risk of rejection by the host. Furthermore, it eliminates the need for inaccurate insulin injections, because the β-cells themselves are functioning to maintain glucose homeostasis, as they would if they were in the body.
"These smart insulin approaches are exciting because they hold the promise of giving patients some time off with regards to their diabetes self-care. It would not be a cure but a desperately needed vacation." – John Buse.
For more information, you may refer to the original publication here.