Johns Hopkins undergraduates have invented a device to improve cell therapy for diabetes patients by anchoring transplanted insulin-producing cells inside a major blood vessel.
A team of five seniors and two freshmen, working with Johns Hopkins doctors and engineers, devised a protective "pouch" that should fit inside the portal vein, which feeds into the liver. This pouch would keep microcapsules of therapeutic cells in one place, allowing them to thrive and send out needed insulin. The inventors say the same approach could be used in cell therapy for other ailments, including liver disease.
"I think it's a brilliant idea," said one of the project's sponsors, Jeff W. M. Bulte, director of the Cellular Imaging Section in the Johns Hopkins Institute for Cell Engineering.
The pouch is formed by sandwiching a porous band of nylon mesh between two concentric metal stents, similar to the ones used to keep clogged blood vessels open. Once the stents are in place, microcapsules filled with helpful cells are injected into the gap between the stents, where they become trapped within the nylon mesh. Blood flowing through the vessel should nourish the encapsulated cells and circulate the proteins, such as insulin, produced by these cells.
The project is important because it could lead to better results from cellular therapy, in which live cells are injected to repair or replace damaged or depleted tissue. "It's a device," Bulte said, "that allows the microcapsules to be removed and reinserted if additional therapy is needed - a 'yearly refill,' for example - and the students have provided an ideal environment in which the encapsulated cells can thrive."
Along with other undergraduate projects, this prototype was unveiled May 2 at the university's Biomedical Engineering Design Day showcase. The Johns Hopkins Technology Transfer staff has applied for a provisional patent. Animal testing is expected to begin this summer. If it is successful, human trials would follow.
"It's very impressive," said Aravind Arepally, an interventional radiologist who served as the project's other sponsor. "We're basically creating a small bio- reactor inside the vein to produce insulin and other proteins that the body needs. The students have built a housing in which the bio-reactor can operate. I'm pretty optimistic that it will work in living subjects."