Above: Stick/ribbon model of an amyloid beta peptide (Ayacop, Wikimedia Commons)

Alzheimer’s and diabetes are two of the most common diseases worldwide. The bodies of people with diabetes either can’t produce enough of the hormone insulin or their insulin can’t convert excess glucose (sugar) to glycogen (stored energy). As a result, blood sugar levels get too high. This can cause fatty deposits to build up in arteries, leading to blockages that result in heart attack or stroke. Diabetes can also cause to nerve damage throughout the body, as well as vision loss from blocked blood vessels in the retina.

Researchers have also begun to find links between diabetes and Alzheimer’s disease. Alzheimer’s is a neurodegenerative disease (brain disease) that affects a person’s ability to remember, think, and understand. It starts slowly and progresses over time. A better understand of the link with diabetes could help researchers learn more about Alzheimer's. It could even lead to treatments or ways of preventing the disease. And the fact that both diseases are so common means that there are lots of opportunities to study the link.

Did you know? According to the World Health Organization, 9% of adults worldwide were living with diabetes in 2014.

Medical researchers at Washington University in St. Louis have highlighted one possible connection between Alzheimer’s and diabetes. They found a link between high blood sugar levels and a decline in brain function, such as memory loss. This seems to be especially true for people older than 65. And it means that means diabetes could make conditions such as Alzheimer’s even worse, especially in older patients.

Increased blood glucose levels in people with diabetes can also lead to increased levels of amyloid beta. They are one types of peptide that make up amino acids. Pieces of amyloid beta proteins can cause communication problems in the brain by clumping together and forming plaques between neurons (brain cells). The formation of these plaques is part of the development of Alzheimer’s disease.

To explore this link between blood sugar and brain disease, researchers injected glucose into the bloodstream of mice. In young mice that without plaques in their brains, doubling the amount of glucose increased amyloid beta levels in the brain by 20 per cent. In older mice that already had plaques in their brains, doubling the amount of glucose led to a 40 per cent increase in amyloid beta levels.

Furthermore, there appears to be a link between insulin production and the production of amyloid beta. Brain cells contain openings called KATP channels, which help control the production of insulin in the pancreas. These channels close when blood glucose levels increase, causing more insulin to be produced. But the closing of KATP channels also causes more amyloid beta to be produced. This could lead to more of the plaques that cause Alzheimer’s disease. To further explore the link, researchers have begun giving mice drugs normally used to treat diabetes.

Did you know? Mice are used in laboratory research because their anatomy and genetics are similar to those of humans. They are are also relatively cheap and small.

According to the World Health Organization, diabetes causes about 1.5 million deaths every year. By 2030, it is expected to be the seventh leading cause of death. Meanwhile, Alzheimer’s disease is the sixth leading cause of death in United States. Hopefully, studying the multiple and interesting connections between diabetes and Alzheimer’s will provide researchers with an opportunity to better understand and find effective treatments for both diseases.

Learn More!

Press release and news article about research on the link between diabetes and Alzheimer’s disease:

New link between diabetes, Alzheimer's found (2015)
Washington University in St. Louis, ScienceDaily

Diabetes and Alzheimer’s Disease – What’s The Link? (2014)
Viatcheslav Wlassoff, BrainBlogger

General information on dementia and Alzheimer’s disease:

Dementia (2015)
World Health Organization

About dementia
Alzheimer Society of Canada

Alzheimer’s Disease
Alzheimer’s Association of the United States

Press release and scientific articles on the role of amyloid beta and KATP channels:

Scientists reveal how beta-amyloid may cause Alzheimer's (2015)
Stanford Medicine News Center

Alzheimer's disease and the amyloid-beta peptide (2010)
M. P. Murphy & H. Levine III, Journal of Alzheimer’s Disease 19

The structure and function of the ATP-sensitive K+ channel in insulin-secreting pancreatic β-cells (1999)
T. Miki, K. Nagashima & S. Seino, Journal of Molecular Endocrinology 22

Sakina Bano Mendha

I am a Student currently enrolled doing my biology undergraduate studies from Montreal, Canada. I like playing badminton and doing Calligraphy. Skills: Public speaking, writing, research, teamwork. 

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