β-Cell Specific Cytoprotection by Prolactin on Human Islets

Introduction Many cytoprotective agents have been reported to improve islet isolation and transplantation outcomes. However, several of these agents improve all cell subsets within an islet preparation; selection of non–β-cell components (eg, acinar cells) may have a negative effect on β-cell function and survival. In this study, we examined the effect of prolactin (PRL) supplementation in the culture medium to determine whether it exerted β-cell–selective cytoprotection on islet viability and function. Materials and Methods Human islets were precultured with or without recombinant human PRL (500 μg/L) for 48 hours. The fractional viability and cellular composition of non–β-cell and β-cell–specific components were assessed using FACS and Laser Scanning Cytometry (LSC). Islet potency was assessed in vivo by transplantation into chemically induced diabetic immunodeficient mice. Results The relative viable β-cell mass and the relative islet β-cell content in the PRL group were 28% higher (P = .018) and 19% higher (P = .029) than the control group, respectively. All transplanted mice achieved normoglycemia in both groups, indicating that PRL treatment did not alter islet function. Conclusion PRL treatment improved β-cell–specific viability and survival of human islets in vitro. The development of novel β-cell–specific cytoprotective strategies may be of assistance in improving islet transplantation.