New biomaterial promotes immune tolerance of transplanted pancreatic cells
To overcome the shortage of insulin-producing beta cells in type 1 diabetes, the transplantation of islets, a group of cells in the pancreas, is a treatment option offered to patients – however, patients are then required to take lifelong immunosuppressive drugs to prevent rejection of the transplanted cells. A research team at Massachusetts General Hospital (MGH) have now developed a novel biomaterial that allows for the transplantation of islets, without the need for long-term immunosuppression.
The biomaterial contains a protein called SA-FasL that promotes immune tolerance: the protein is tethered to the surface of microgel beads in a matrix and can be mixed with islets. In a nonhuman primate model of type 1 diabetes, the biomaterial was transplanted to a bioengineered pouch formed by the omentum – a fold of fatty tissue that hangs from the stomach and covers the intestines. After the transplant, the primates were put on a three-month course of a single anti-rejection drug (rapamycin).
Dr. Ji Lei, an Associate Immunologist and Director of the Human Islet/Cell Processing Special Service cGMP Facility at MGH, said transplanting islets to the omentum has several advantages over the current clinical approach of transplanting to the liver. “Unlike the liver, the omentum is a non-vital organ which allows for removal should undesired complications be encountered. [Thus] the omentum is a safer location for transplants to treat diabetes and may be particularly well suited for stem-cell-derived beta cells and bio-engineered cells.”
As the test transplant successfully created a thriving environment that allowed islets to survive without long-term immunosuppression, in addition to achieving robust blood glucose control in all diabetic nonhuman primates, Dr. Li believes it to be a viable option for treatment.
“We believe that our approach allows the transplants to survive and control diabetes for much longer than [research period of] six months without anti-rejection drugs because surgical removal of the transplanted tissue at the end of the study resulted in all animals promptly returning to a diabetic state,” Dr. Li said.
Another clinical trial is being planned based on the researchers’ results.
Read: A heathier diabetes management plan for the new normal
