Islet encapsulation offers the perspective to avoid immunosuppressant therapy during islet transplantation. The concept of encapsulation is to apply a physical barrier between the cells and the immune system.
Besides, current macro (multiple cells/device) immunoisolation devices suffer from a lack of manufacturing reproducibility. One of their features is the large surface area needed to well perfuse all the islets, limiting their implantation to poorly vascularized graft site, or, in case of islets packing macrocapsule’s strategies, the daily need of oxygen refill.
Courtesy of University of Alberta and the Clinical Islet Transplantation (CIT) Consortium, sponsored by National Institute of Diabetes & Digestive & Kidney Diseases (NIDDK) and National Institute of Allergy and Infectious Diseases (NIAID)
Microcapsules present the double advantage of a good exchange with the surroundings media, and a graft volume reduction allowing new sites of implantation. If needed for regulatory issues (such as easy graft collection), microcapsules could still be embedded in a loose porosity bag similar to that which has already been approved (hernia mesh).
Several encapsulated islet approaches have been ongoing for over 30 years without defining a clinically relevant product.