Is aggregated IAPP a cause of beta-cell failure in transplanted human pancreatic islets?

Aggregation of the beta-cell product islet amyloid polypeptide (IAPP) is believed to be an important event in the development of the beta-cell lesion in type 2 diabetes. Preamyloidotic oligomeric IAPP assemblies exert toxic effects on beta cells that die, leading to reduced beta-cell mass. Normal human islets, when isolated and cultured in vitro or transplanted into nude mice, also develop amyloid deposits, which are associated with increased beta-cell death and reduced beta-cell mass. The possible role of IAPP aggregation and amyloid formation in loss of islet transplant function should be taken into consideration and studied further.