People with Type 2 diabetes have an excess of a protein
called islet amyloid polypeptide, or IAPP, and the accumulation of this protein is linked to the loss of insulin - producing pancreatic beta cells.
Fibrils immunoreactive
for islet amyloid polypeptide are found in macrophages associated with amyloid, suggesting that deposits can be phagocytosed.
To corroborate the findings, the researchers also developed a novel mouse model that was deficient for autophagy specifically in beta cells with expression of the human form
of islet amyloid polypeptide.
Islet amyloid polypeptide: Pinpointing amino acid residues linked to amyloid fibril formation
Preliminary results of histological examination of pancreatic tissue show a similar range of islet pathology in diabetic Burmese and diabetic domestic cats, which suggests that the mutation does not directly result in excessive deposition of
islet amyloid polypeptide or another metabolic product causing destruction of β - cells (personal communication, R. Lederer, 2003).