Entwicklung eines molekularen Assay zur Prüfung der Inselzellqualität vor Transplantation im diabetischen Tiermodell

Introduction: Since the recent introduction of the Edmonton experience by Shapiro et al. the trans-plantation of insulin producing tissue has become an attractive therapeutic approach for the treatment of type 1 diabetes. However, in order to transfer this therapy into clinical routine, the currently available pancreatic tissue has to be used more efficiently. An essential criterion for that is the assessment of islet quality which can vary dramatically depending on donor related factors and the isolation procedure. Still, up to now it is not possible surely to predict the metabolic performance of islets after transplantation. Material and methods: Pancreatic islets of male Lewis rats were cultured for 24 hours after isolation. Samples of these islets were exposed to 2 hours glucose stimulation (25 mM). After stimulation, the insulin secretion index was measured as well as the binding activity of polypyrimidine tract-binding protein (PTB) onto the m-RNA of selected markers of secretory granules (ICA-512, PC1). In a syngenic transplantation model the islets were transplanted under the kidney capsule of diabetic Lewis rats as 1500 islet equivalents (IEQ), 1800 IEQ, 2000 IEQ and 2500 IEQ. The metabolic performance of the transplanted islets was monitored by daily measurements of blood glucose values and body weight for 3 months. Results: We were able to show the stabilization of insu-lin-mRNA and further markers of secretory granules through a RNA binding protein (PTB). The stabilization effect occurs after the translocation of PTB from the nucleus into the cytoplasm through phosphorylation and binding on the specific mRNAs.