Type 2 diabetes may spread like a prion disease, researchers report

John Murphy, MDLinx | August 14, 2017

Type 2 diabetes could be spread like an infectious prion disease, such as Creutzfeldt-Jakob disease or mad cow disease, according to a new proof-of-concept study published in The Journal of Experimental Medicine

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Misfolded IAPP aggregates

Among patients with type 2 diabetes, more than 90% have accumulated protein aggregates, composed mainly of misfolded islet amyloid polypeptide (IAPP).

Recent research has shown that both type 2 diabetes and protein misfolding disorders (PMDs) are characterized by the accumulation of misfolded protein aggregates. PMDs include not only prion diseases, but also neurodegenerative diseases such as Alzheimer’s, Parkinson’s, and amyotrophic lateral sclerosis. Among patients with type 2 diabetes, more than 90% have accumulated protein aggregates, composed mainly of misfolded islet amyloid polypeptide (IAPP).

When investigators at the McGovern Medical School at The University of Texas Health Science Center at Houston injected small amounts of misfolded IAPP aggregates into the pancreatic tissue of mice without diabetes, the mice developed symptoms associated with type 2 diabetes, including hyperglycemia, impaired glucose tolerance, and a substantial loss in the number and mass of pancreatic β cells. 

The experiment demonstrated that misfolded IAPP aggregates can act as “seeds” to induce the aggregation process throughout the pancreatic islets—or even to other people (under experimental conditions at least). 

“The similarities between the molecular mechanism of prion propagation and the process of protein misfolding and aggregation in PMDs suggest that misfolded aggregates have an inherent ability to be transmissible,” the investigators wrote.

Does that mean that diabetes could be infectious?

Until now, the worldwide increase in the incidence of type 2 diabetes has been mostly attributed to changes in lifestyle and increased obesity rates, the investigators noted. But anecdotal studies have also reported an increased risk for diabetes after blood transfusions and organ transplants, which may suggest a possible means of transmission.

“Our data suggesting that some aspects of type 2 diabetes pathology might be transmissible could open an entirely new area of research with profound implications for public health,” the authors concluded.

“However, considering the experimental nature of the models and conditions used in this study, the results should not be extrapolated to conclude that type 2 diabetes is a transmissible disease in humans without additional studies,” they added. “Perhaps of greater importance than a putative interindividual transmission, the prion phenomenon may have a key role in spreading the pathology from cell to cell or from islet to islet during the progression of the disease.”

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