Islet amyloid polypeptide-like immunoreactivity in the islet B cells of type 2 (non-insulin-dependent) diabetic and non-diabetic individuals

Diabetologia. 1987 Nov;30(11):887-92. doi: 10.1007/BF00274799.

Abstract

A novel peptide, islet amyloid polypeptide (IAPP), with structural resemblance to calcitonin gene-related peptide has recently been purified from amyloid deposits in an insulinoma and from islets of Langerhans. By immunohistochemical methods, using antisera to a synthetic undecapeptide of IAPP and to insulin, we show that freshly fixed islet B cells in man, guinea pig, rat, mouse and hamster exhibit strong IAPP-immunoreactivity while A cells are unreactive. In human autopsy material, all of 11 non-diabetic individuals had IAPP immunoreactivity of the islets. In comparison 8 of the 13 patients with Type 2 (non-insulin-dependent) diabetes had no IAPP immunoreactive cells. The proportion of islet cells having IAPP immunoreactivity exceeded 10% in only 1 of the 5 remaining diabetic patients while in all 13 patients substantially more than 10% of the islet cells contained immunoreactive insulin. IAPP-positive amyloid deposits were found in 20-99% of the islets in 12 of the Type 2 diabetic patients while 6 of 11 non-diabetic subjects had amyloid in 3-11% of their islets. In islets with IAPP-immunoreactive amyloid, very few IAPP-cells were seen despite a strong reaction of the B cells with antiserum to insulin. This study shows that IAPP is a normal islet B cell component and that IAPP immunoreactivity in B cells is diminished in Type 2 diabetes while IAPP is deposited as amyloid fibrils in the islets of Langerhans. Although the function of IAPP is unknown, its occurrence in the islet B cells and its structural relation to calcitonin gene-related peptide makes a hormonal nature probable.(ABSTRACT TRUNCATED AT 250 WORDS)

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Amyloid / analysis*
  • Diabetes Mellitus, Type 2 / pathology*
  • Female
  • Humans
  • Immunohistochemistry
  • Insulin / analysis
  • Islets of Langerhans / analysis*
  • Male
  • Middle Aged
  • Pancreatic Polypeptide / analysis*

Substances

  • Amyloid
  • Insulin
  • Pancreatic Polypeptide