RAPID DEPOSITION OF AMYLOID IN HUMAN ISLETS TRANSPLANTED INTO NUDE-MICE

Human islets of Langerhans were transplanted to the subcapsular space of the kidneys of nude mice which were either normoglycaemic or made d iabetic with alloxan. After 2 weeks, the transplants were processed fo r light and electron microscopical analyses. In all transplants, islet amyloid polypeptide (IAPP)-positive cells were found with highest fre quency in normoglycaemic animals. IAPP-positive amyloid was seen in 16 out of 22 transplants (73%), either by polarisation microscopy after Congo red staining or by immune electron microscopy. At variance with previous findings of amyloid deposits exclusively in the extracellular space of islets of non-insulin-dependent diabetic patients, the graft ed islets contained intracellular amyloid deposits as well. There was no clear difference in occurrence of amyloid between diabetic and non- diabetic animals. The present study indicates that human islets transp lanted into nude mice very soon present IAPP-positive amyloid deposits . This technique may provide a valuable model for studies of the patho genesis of islet amyloid and its impact on islet cell function.