Mini-Organ Shows Promise for Type 1 Diabetes
Julia Greenstein, vice president of Cure Therapies for JDRF (formerly the Juvenile Diabetes Research Institute), said the risks of islet cell transplantation currently outweigh the benefits for healthy people with type 1 diabetes.
That's where the BioHub comes in.
"The BioHub is like a nest that the islet cells will sit in and be protected and cared for," Inverardi said. "It's a transparent, flat structure about the size of a quarter. It's shaped so you can put the islet cells in it, and it's porous to allow [the islets to develop a new blood supply]."
The device is made of a silicone compound that's already in use for other medical conditions. "The BioHub is ... like an open frame, with about 95 percent air. The design keeps the islets from clumping together," said Ricordi, who added that this would likely translate to a need for fewer islet cells. And, he said, the design allows the researchers to add new components as they're developed and approved.
In the future, the BioHub might be in an even more natural container, such as a tied-off vein that would create a sac to hold the islet cells, Ricordi said. The advantage of a vein is that the blood supply is already there.
Initially, the researchers will implant the BioHub in the omental pouch, an area in the lining of the abdominal cavity that connects the stomach to other abdominal organs. Once there, the BioHub would sense changing blood-sugar levels and would release insulin when needed.
Inverardi said one of the biggest advantages to the BioHub is that researchers will easily be able to find the best site to transplant islet cells, because if a site doesn't work well, the device can be easily retrieved.
Inverardi and Ricordi both expect this phase to go well, and expect the BioHub with the transplanted islets to begin producing insulin.
Eventually, the researchers hope to develop and test immune suppression that is only in the area of the islet cells, instead of affecting the whole body. One possible way to accomplish this, Inverardi said, is to encapsulate the islet cells in a material that allows the cells to breathe and exchange insulin, but will repel any immune attack. At this point, there is no timeline scheduled for clinical trials of this portion of the BioHub.
The researchers also hope to find alternative sources for islet cells to use in the BioHub. Possible avenues of research include living, related donors; islet cells from pigs; and stem-cell-produced islets.
"We're excited about this research," Greenstein said. "This is an incremental step that indicates progress, but, until we get rid of the need for chronic immunosuppression, the use is limited to those with severe [low blood sugar] unawareness."