Encapsulated islet transplants restore blood sugar control in diabetic mice

Islet transplantation, in which insulin-producing islet cells from a donor are implanted into a patient’s liver, is a promising therapy for type 1 diabetes. To prevent rejection of the donated cells, however, recipients need to continuously take immunosuppression drugs. Using a new type of cell encapsulation, researchers at The Pennsylvania State University demonstrated that diabetic mice could maintain normal blood glucose levels for 100 days, without requiring immunosuppressants. This represents a substantially longer time period than traditional cell therapies for diabetes.

The Penn State researchers developed their cell encapsulation process based on the molecular characteristics of the zona pellucida, a thin membrane that coats mammalian eggs. Once an egg is fertilized, biochemical reactions lead to hardening of the zona pellucida, which acts as a protective shield during embryo development. Here, biomimetic zona pellucida (BZP) encapsulation serves to hide the donor islets from the body’s immune system.