The Link Between Diabetes and Alzheimer’s Continues to Motivate Researchers

The link between Alzheimer’s and diabetes is well-understood. However, the amyloid hypothesis has dominated Alzheimer’s research in recent years. Based on a series of failed drug trials, many researchers are now exploring other avenues — including the association between Alzheimer’s and diabetes.

New Avenues of Research May Combat Alzheimer’s

Many experts agree that the continued failure of new drugs could be interpreted as substantial proof that amyloid is not the core cause of this neurodegenerative disease. Although some drug companies are now switching their focus to the impact of tau (another key protein associated with the development of this disease), others are exploring new possibilities.

These new avenues cover a range of theories, often focusing on key risk factors. By better understanding how these risk factors impact the development and prognosis of Alzheimer’s, researchers can potentially intervene. Since the association between diabetes and Alzheimer’s is so significant, the impact that diabetes has on the brain is a key area of interest.

When suffering from diabetes, a patient’s insulin becomes less effective. This mainly impacts blood glucose levels, resulting in dangerous symptoms. However, insulin is critical for a number of functions, including its impact on growth factor. Without insulin’s growth factor, neurons become much more vulnerable to stress. Over time, the brain then loses its ability to repair the damage.

Non-diabetics also exhibit issues with insulin’s growth factor 

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What is even more interesting, is that while studying brain tissue from deceased Alzheimer’s patients, the loss of insulin’s growth factor was not just apparent in diabetics. Even those who did not suffer from diabetes showcased issues with insulin’s effectiveness as a growth factor.

This has led researchers to believe that diabetic drugs may help combat Alzheimer’s. In fact, animal studies have already shown positive results. In one 2018 study, published in Neuropharmacology, it was stated that GLP-1/GIP receptor agonists (which are used to treat diabetes), also show significant neuroprotective effects.

Overall, they show a clear ability to reduce inflammation and oxidative stress. They also appear to protect memory formation, synaptic activity, motor activity, and dopaminergic neurons, while supporting the brain’s ability to utilize energy. This means that GLP-1 and GIP mimetics offer significant potential for treating Parkinson’s and Alzheimer’s.

A Newly Discovered Mechanism Common to Type 2 Diabetes and Alzheimer’s

Fernanda De Felice, an associate professor at Queen’s University, recently discovered a common mechanism relevant to both Alzheimer’s and Type 2 diabetes. Consisting of a specific pathway, this mechanism causes inflammation in various areas of the brain. In turn, this leads to glucose intolerance and the degeneration of synapses.

Presented at the Canadian Neuroscience Meeting in May 2018, this discovery could lead to new therapies. Studying mice and non-human primates, Felice was able to identify the pathway that increases brain inflammation, as well as its impact on insulin signaling.

In her previous research, Felice and her team tested the diabetes drug known as liraglutide. What they found was that this drug could alter insulin sensitivity. It was also able to to reverse cognitive impairment and restore synapses in non-human primate models of Alzheimer’s. This further supports the importance of exploring new, probable theories outside of the amyloid hypothesis.

If you are currently living with diabetes and are concerned that you may be experiencing early warning signs of Alzheimer’s or another form of dementia, please consider the BrainTest® app. This assessment tool can be used within the comfort of your home, allowing you to better determine your current level of cognition. Your results can then be discussed with your physician.

The Link Between Smoking, Diabetes, and Memory Decline

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Another recent study found a link between diabetes and cognitive impairment. However, this time, the research also focused on the effects of smoking. After studying 1,991 patients (average age 78 years), the researchers made an interesting discovery. What they found was that individuals who smoke or have diabetes are at an increased risk of calcifications. More specifically, calcifications in the hippocampus (the region of the brain associated with memory).  

Although calcifications in the hippocampus region are common as we age, it was unclear whether or not these calcium deposits had any impact on cognition. Of the 1,991 patients studied,19.1 percent had calcifications in the hippocampus. Older age, smoking, and diabetes were all associated with an increased risk.

Moving forward, the researchers plan to study various groups to better understand the potential risk factors associated with brain calcifications. Interested in how these variables influence cognition, this research will also support vascular disease research. Since the cardiovascular system and the brain significantly impact one another, this could lead to exciting new discoveries.

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Krista Hillis has a B.A.Sc degree, specializing in neuroscience and psychology. She is actively involved in the mental health and caregiving community, aiming to help others. Krista is also passionate about nutrition and the ways in which lifestyle choices affect and influence the human brain.

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