Biomaterial particles educate immune system to Accept Transplanted Islets
Source: Georgia Institute of Technology
Summary: Researchers have opened a potentially new pathway for treating type 1 diabetes by instructing key immune system cells to accept transplanted insulin-producing islets.
In the United States, some 1.25 million persons have type1 diabetes, which is different from the more common type 2 diabetes. Type 1 diabetes is caused by immune system destruction of the pancreatic islet cells that produce insulin in response to glucose levels. Treatment involves a frequent injection of insulin to replace what the islets no longer produce. There is no long-term cure for the disease, though persons with type 1 diabetes have been treated experimentally with islet cell transplants which almost always fail after a few years even with strong suppression of the immune system. Researchers from the Georgia Institute of Technology have opened a potentially new pathway for treating type 1 diabetes by instructing key immune system cells to accept transplanted insulin-producing islets. The study findings were published in the journal Nature Materials.
The technique uses synthetic hydrogel particles (microgels) to present a protein known as the Fas ligand (FasL) to immune system T-effector cells along with the pancreatic islets being transplanted. The FasL protein “educates” the effector cells which serve as immune system watchdogs causing them to accept the graft without rejection for at least 200 days in an animal model. The FasL-presenting particles are simply mixed with the living islets before being transplanted into the mice, which suffer from chemically-induced diabetes. The researchers believe the FasL-presenting hydrogels would not need to be personalized, potentially allowing an “off-the-shelf” therapy for the transplanted islets. If the approach is ultimately successful in humans, it could allow type 1 diabetes to be treated without the long-term complications of immune system suppression.
Prof. Andrés García said, “Clinical trials with transplantation of islets showed effectiveness, but after a few years, the grafts were rejected. There is a lot of hope for this treatment, but we just can’t get consistent improvement.”
More Information: Devon M. Headen et al, “Local immunomodulation with Fas ligand-engineered biomaterials achieves allogeneic islet graft acceptance”, Nature Materials (2018). DOI: 10.1038/s41563-018-0099-0