Immunoisolation effect of polyvinyl alcohol (PVA) macroencapsulated islets in type 1 diabetes therapy

Islet transplantation has shown great success in the treatment of type 1 diabetes since the Edmonton protocol was established. However, it still has two major problems to overcome: the lack of organ donors and the side effects of immunosuppression. Encapsulated islets have emerged as a potential option for islet transplantation because it can, at least partly, overcome these two problems. Wistar rat islets suspended in 3% polyvinyl alcohol (PVA) hydrogel were frozen-thawed to make macroencapsulated islets (MEIs). The recovery rate, insulin content, and morphological change in culture medium with/without fresh human plasma (FHP) were measured in MEIs and free islets in vitro. In vivo, MEIs of either Wistar or Lewis rats were transplanted into the peritoneal cavity of streptozotocin (STZ)-induced diabetic Lewis rats and nonfasting blood glucose (NFBG), body weight, and histological evaluations were processed. FHP destroyed rat free islets but did not affect the islet morphology, islet recovery rate, or insu...