Implantable Medical Devices Protect Transplanted Cells
Background:
For nearly 30 years, the liver was thought to be an ideal location for transplanting insulin-producing islet cells. The liver is rich in blood and oxygen, which islet cells require, and is easily accessible. But in the past decade, there has been mounting evidence that the liver may not be the optimal site - and that new approaches may offer a safer and less toxic environment for the transplanted cells.
Research Focus:
Alternate transplant locations must be identified. In one approach being pursued here at the Diabetes Research Institute, our scientists are designing implantable medical devices that can house and protect transplanted cells. These bioengineered “containers” hold many cells and, if necessary, can be retrieved.
In a recent study, our researchers implanted a small, biohybrid mesh cylinder under the skin (subcutaneous) and allowed a network of blood vessels to grow in and around the mesh. Following adequate vascularization, islet cells were inserted into the cylinder and the “already established” blood vessels were able to immediately deliver oxygen and other vital nutrients to the cells.
We tested this biohybrid technology in the mouse model, and the results show islets implanted in the biohybrid container functioned comparably to those of a traditional islet infusion.
Leading to a Cure: How this Research Supports our Mission
This implantable device offers an optimal environment within which transplanted islets can be protected and survive. Think of it as a self-contained mini “organ” that’s been engineered to provide islet cells with the best chance to thrive.
And while these devices offer hope for the long-term viability of transplanted cells, this type of biohybrid solution provides another distinct advantage to diabetes patients.
Currently, islet transplant recipients must take powerful, systemic immunosuppressant (anti-rejection) drugs for life. These drugs often cause unwanted side effects, including damage to the islets themselves. They also shut down the patient’s entire immune system, leaving him or her susceptible to other viruses and infections.
By contrast, because these synthetic devices, containing the transplanted islets, are easily identified and tracked, scientists can use them to pinpoint the delivery of anti-rejection drugs to a precise location. As a result, in our mouse study, just 1/100th of the amount of anti-rejection drugs was required – minimizing side effects for the transplant recipient.