A thread-like implant, or SHEATH (Subcutaneous Host-Enabled Alginate THread), stimulates the body’s production of insulin, a hormone that regulates blood sugar levels.
In type 1 diabetes mellitus, the body’s immune system attacks and destroys the insulin-producing cells of the pancreas (the so-called islets of Langerhans), which prevents secretion and requires lifelong insulin injection or the use of an insulin pump. But now researchers from Cornell University, in collaboration with the University of Alberta, have proposed a method that will actually generate such islands and stimulate the production of the necessary hormone.
At the beginning, a thread-like nylon implant is inserted under the skin for about 4-6 weeks, which causes a controlled inflammatory reaction and thus “assembles” a network of blood vessels around it. Then the device is removed, and an alginate device with “island cells” up to 10 cm long is inserted into the formed “pocket”, which provides oxygen and nutrients to the previously collected blood vessels.
“It can be done on an outpatient basis, under local anesthesia, so you don’t have to stay in the hospital for a long time.”
SHEATH was implanted in mice with diabetes, which led to the reversal of their condition without the need for immunosuppression.
Experiments have shown a reliable ability to treat diabetes for a long time – with some mice achieving correction of high blood glucose levels for more than 190 days. In addition, the system allowed for the removal and replacement of a faulty implant.
To confirm the scalability of the system, the researchers successfully developed procedures for implementing SHEATH in minipigs, including implant insertion, removal, and replacement.
In the future, it is still necessary to determine the acceptable length of the implant and the anatomically appropriate places for their placement.
“The problem is that it is difficult to keep these islets functional for a long time in the body with the device. It’s designed so that we can maximize massive nutrient and oxygen exchange, but we may need to provide additional means to maintain the cells for long-term operation in large animal models and eventually in humans.”
Despite these problems, the researchers hope that future versions of the implants will be able to last from two to five years before they need to be replaced.
