17beta-Estradiol protects isolated human pancreatic islets against proinflammatory cytokine-induced cell death: molecular mechanisms and islet functionality.

Academic Article

Abstract

  • INTRODUCTION: Proinflammatory cytokines (PIC) (interleukin-1beta, interferon-gamma, and tumor necrosis factor alpha) are released after intraportal islet transplantation lead to functional suppression and islet apoptosis. Estradiol has been shown to promote survival of cells undergoing PIC-induced apoptosis. In this study, we evaluated the effects of estradiol on isolated human pancreatic islet (IHPI) survival after exposure to PIC and analyzed potential mechanisms of action. METHODS: Hand-picked, freshly isolated IHPI were incubated with PIC and estradiol. Viability was analyzed from single islet cells stained with ethidium bromide and acridine orange, apoptosis using a quantitative kit, NF-kappaB nuclear translocation using a promoter-Luciferase NF-kappaB responsive construct, mitochondrial permeability transition using the ApoAlert Mitochondrial kit, and caspase 9 by a fluorometric assay. In vitro functionality was examined by static incubation, and a limited number of islets were transplanted in nonobese diabetic, severe combined immunodeficient mice. RESULTS: 17beta-Estradiol induced a dose-dependent increase in islet viability, an effect partially reversed by the estrogen receptor antagonist ICI 182,780. In vitro, islets treated with estradiol presented higher stimulation index. Euglycemia was achieved in 6 of 12 animals that received estradiol-treated islets compared with 1 of 12 control animals. Lower NF-kappaB nuclear translocation, cytochrome release, and caspase 9 activation occurred in islets treated with estradiol. CONCLUSIONS: Estradiol promoted IHPI survival and improved functionality after PIC exposure in vitro and in vivo after transplantation. The molecular mechanisms involved included a decrease in NF-kappaB nuclear translocation, decrease in mitochondrial cytochrome release, and caspase 9 activation. The use of estradiol might be beneficial in clinical islet transplantation.
  • Published In

  • Transplantation  Journal
  • Keywords

  • Animals, Biological Transport, Blood Glucose, Cell Death, Cell Nucleus, Cytokines, Diabetes Mellitus, Experimental, Diabetes Mellitus, Type 2, Estradiol, Glucose, Humans, In Vitro Techniques, Inflammation Mediators, Insulin, Islets of Langerhans, Islets of Langerhans Transplantation, Mice, Mice, Inbred NOD, Mice, SCID, Mitochondria, NF-kappa B
  • Digital Object Identifier (doi)

    Author List

  • Contreras JL; Smyth CA; Bilbao G; Young CJ; Thompson JA; Eckhoff DE
  • Start Page

  • 1252
  • End Page

  • 1259
  • Volume

  • 74
  • Issue

  • 9