Cryopreservation, transplantation, and susceptibility to diabetogenic agents of fetal porcine proislets

Abstract: This study reports the morphology and in vitro function of fetal porcine proislets (FPP) after cryopreservation or culture and the in vivo effects of frozen‐thawed FPP in comparison to cultured FPP on the glucose metabolism after transplantation into nude mice rendered diabetic by streptozotocin (STZ). Furthermore, the morphology and the in vitro function of removed grafts is examined in an in vitro:ex vivo model and the in vitro and in vivo effects of FPP of the diabetogenic substance, STZ, is assessed. The data demonstrate that cryopreservation has no adverse effects on the morphology and in vitro function of FPP when compared to cultured FPP. Frozen‐thawed FPP are equally effective to normalize blood glucose levels in nude mice rendered diabetic by streptozotocin. Histological and in vitro:ex vivo examination of the removed graft revealed that the extent of differentiation and proliferation in vivo of cryopreserved FPP is comparable with that of cultured FPP. Streptozotocin is not toxic (diabetogenic) to FPP, neither in vitro nor in vivo. We conclude that cryopreserved fetal porcine proislets, easily yielded and pooled from pregnant sows bred in a microbiologically controlled environment, may be a potential source for future xenotransplantation in Type 1 diabetic humans.