Combining a Novel Islet Encapsulation Material With a Nanotherapy Leads to Long-Term Glycemic Control in Diabetic Mice

Two major immune hurdles need to be addressed to achieve successful cell therapy for diabetes: (i) preventing the rejection of foreign implanted cells, and (ii) preventing the continuing autoimmune attack on the newly implanted beta cells. Nanotherapeutics offer a novel approach to overcome these problems and this publication reports on studies of whether creation of ‘‘stealth’’ islets encapsulated within a very thin cage of a special material (modified using polyethylene glycol and special nanoparticles) provides a viable option for islet transplantation and potentially encapsulation products. The aims of this study were to test islet viability and functionality following encapsulation within the special cage materials in diabetic mice. The authors created a series of special cages each with a unique type of functional nanoparticle. The study results showed the special cage/nanoparticle combination maintained normal glucose control in 30%; 43%, and 57% of the mouse recipients with the various material/nanoparticles tested for over 100 days compared to about 17 days in the mice transplanted with unprotected cells. In conclusion, construction of ‘‘stealth’’ islets using the special cage materials with nanotherapeutics not only supports islet structure and function, but also effectively isolates the islets from immune-mediated destruction. The added value of nanoparticles to deliver immune modulators plus growth factors expands the potential of this novel therapeutic approach to cell therapy for diabetes.

Ramifications for Individuals with T1D:
This is a promising new approach to developing an encapsulation therapy to achieve beta cell replacement and insulin independence in individuals with T1D without the use of chronic immunosuppression.

JDRF Involvement:
This study was funded in part by JDRF.

Investigators and Institutions:
This study was conducted by Dr. Hongjun Wang and her colleagues at the University of South Carolina.

Dong H, Fahmy TM, Metcalfe SM, Morton SL, Dong X, et al. (2012) Immuno-Isolation of Pancreatic Islet Allografts Using Pegylated Nanotherapy Leads to Long-Term Normoglycemia in Full MHC Mismatch Recipient Mice. PLoS ONE 7(12): e50265. doi:10.1371/journal.pone.0050265. Epub 2012 Dec 5.