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Study Finds a Link Between Microglia, Inflammation and Alzheimer’s

New research has found that microglia can “remember” inflammation. In turn, that memory impacts how these cells target toxic plaque in the brain.

In this study, published in Neuron, researchers found that dysfunctional microglia may play a causative role in neurodegenerative disorders. Although amyloid load was reduced, drastic synapse loss was observed.

Dysfunctional Microglia Threaten the Brain

To clarify, microglia are essentially the ‘immune cells’ of the central nervous system. Sometimes referred to as “scavenger” cells, they target sites of injury or infection. Although these cells fight toxic agents and clear useless cells, they are also known to have a negative role in neurodegenerative conditions, including TBI and Alzheimer’s.

The researchers discovered that while studying mice, that overactive microglia not only devoured toxic plaques but also synapses. Since some microglia cells can survive for more than two decades, the researchers wondered whether immunological memory played a role in Alzheimer’s risk.

They investigated this concern and published their findings in Nature.

Immune Memory In the Brain May Influence Hallmarks of Alzheimer’s

After causing inflammation in mice, the researchers were interested in how this influenced microglia. What they found was that these glial cells could essentially “remember” prior inflammation.

Based on this finding, they explored how this “memory” related to the buildup of amyloid plaque. What they discovered was that after they introduced the first inflammatory stimulus, the production of plaques increased.

They concluded that ‘training’ the immune response exacerbated plaques in the brain, while immune tolerance alleviated production. They also stated that inflammatory diseases that develop outside of the brain may trigger a reprogramming of gene function inside the brain.

More Research on the Role of Inflammation in the Brain

From depression to Alzheimer’s, inflammation may play a key role in a wide range of neurological conditions.

Although the above study has shed some light on the connection between microglia and amyloid plaques, this link has been explored in the past.

In terms of inflammation, unlike an infection which can be defeated, the presence of plaques act as a persistent irritant. It is believed that as microglia battle plaques, damaging chemicals and cytokines result. In turn, healthy brain cells harmed.

There are a number of theories, as these reactions are complex. In animal studies, it has been found that inflammation caused by a virus can lead to Alzheimer’s-like changes in the brain. Severe head trauma also leads to brain inflammation, which may explain why such an injury increases one’s risk of Alzheimer’s later in life.

Current research is focusing on drugs that may help reduce the aggressive response of microglia. This would allow these cells to target amyloid plaques without causing as much collateral damage.

Possible Preventative Measures

Since chronic inflammatory conditions have been shown to increase your risk of dementia, it is imperative that you take a proactive approach. By addressing inflammation in the body, you will also help protect your heart, kidneys, and other organs.

Type 2 diabetes, for instance, has been strongly linked to Alzheimer’s — so has inflammation of the gums. These are the types of conditions that you can actively prevent. However, what about people who develop an autoimmune condition such as arthritis?

Considering autoimmune disorders may increase one’s risk of dementia by 20 percent or more, it is important to take positive action. Although effects vary, one study found that people living with rheumatoid arthritis had a 10 percent lower risk.

The researchers believe that this may be due to the use of non-steroidal anti-inflammatory drugs. Since these may help reduce chronic inflammation, the brain may benefit. They also found that autoimmune conditions, including diabetes, impacted heart health.

This led to an interesting finding. Individuals with autoimmune diseases were 29 percent more likely to develop vascular dementia, yet were only 6 percent more likely to develop Alzheimer’s.

Other than condition-specific drugs, diet and exercise can significantly influence inflammation. You should also practice stress management, as cortisol suppresses the immune system. Over time, this can lead to myriad problems.

For more information, please refer to the following research:

Also, check out the BrainTest app in order to better track cognitive changes across time. If you are concerned with your current level of cognition, it is highly recommended that you address your concerns.


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