Encapsulated β-islet cells as a bioartificial pancreas to treat insulin-dependent diabetes during pregnancy

OBJECTIVE: Our purpose was to determine the effectiveness of the bioartificial pancreas technique in correcting (1) maternal carbohydrate metabolism and (2) fetal malformation rates in a pregnant diabetic animal model. STUDY DESIGN: Insulin secretion from encapsulated rat islets cultured in the presence of homologous rat prolactin was determined and compared with that of controls. Streptozotocin-induced diabetic Balb/c mice were then transplanted with rat islet cells encapsulated within alginate microbeads and were then bred. Blood glucose determinations were made after transplantation and throughout gestation. Pups were delivered by cesarean section on day 19 of gestation. Outcome parameters from the transplanted study animals were compared with those of nondiabetic controls and untreated diabetic animals. RESULTS: Insulin secretion was increased twofold in encapsulated rat islets exposed to prolactin compared with control values. Throughout gestation maternal weights and blood, glucose levels of transplanted animals were similar to those of nondiabetic controls. A fetal malformation rate of only 1.4% was observed in the pups from transplanted animals. CONCLUSIONS: Transplanted encapsulated islets are capable of normalizing maternal carbohydrate metabolism in a pregnant diabetic animal model. This therapy, if instituted before conception, also appears to eliminate the increase in fetal malformations seen in diabetic pregnancies.