Misfolded polypeptides may disrupt insulin secretion in type 2 diabetes

A research team at the University of California, Los Angeles has discovered that small clusters of islet amyloid polypeptides (IAPPSs) may play a role in the development of type 2 diabetes.

Adult-onset diabetes is characterized by high blood glucose and the presence of insulin resistance. Between the years 1990 and 2005, the prevalence of this disease doubled in the United States, as nearly 23.6 million people were diagnosed with the condition.

Patients with type 2 diabetes have a decreasing number of beta cells, which are found in the pancreas and normally secrete insulin. This decrease is associated with the accumulation of misfolded proteins, especially in IAPPs.

The accumulation of IAPPs has also been linked to certain neurodegenerative diseases such as Alzheimer’s, Parkinson’s and Huntington’s disease.

The researchers discovered that small clusters of IAPPs disrupted the membranes of beta cells, blocking proper insulin secretion.

“Taking the present study along with the known properties of toxic IAPP oligomers to induce membrane damage, we conclude that these oligomers may contribute to beta cell dysfunction and apoptosis characteristic of type 2 diabetes,” the authors wrote in their paper.

These findings were published in The American Journal of Pathology.