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Experimental Diabetes Research
Volume 2008 (2008), Article ID 429274, 7 pages
http://dx.doi.org/10.1155/2008/429274
Research Article

Transthyretin and Amyloid in the Islets of Langerhans in Type-2 Diabetes

1Department of Clinical and Experimental Medicine, Linköping University, 581 85 Linköping, Sweden
2Department of Genetics and Pathology, Uppsala University, 751 85 Uppsala, Sweden

Received 31 January 2008; Revised 7 May 2008; Accepted 3 July 2008

Academic Editor: Steven E. Kahn

Copyright © 2008 Gunilla T. Westermark and Per Westermark. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Transthyretin (TTR) is a major amyloid fibril protein in certain systemic forms of amyloidosis. It is a plasma protein, mainly synthesized by the liver but expression occurs also at certain minor locations, including the endocrine cells in the islets of Langerhans. With the use of immunohistochemistry and in situ hybridization, we have studied the distribution of transthyretin-containing cells in islets of Langerhans in type-2 diabetic and nondiabetic individuals. TTR expression was particularly seen in alpha (glucagon) cells. Islets from type-2 diabetic patients had proportionally more transthyretin-reactive islet cells, including beta cells. A weak transthyretin immunoreaction in IAPP-derived amyloid occurred in some specimens. In seeding experiments in vitro, we found that TTR fibrils did not seed IAPP while IAPP fibrils seeded TTR. It is suggested that islet expression of transthyretin may be altered in type-2 diabetes.