Alcohol use affects the brain’s immune system

A new study led by Binghamton University has found that heavy alcohol use can have a major impact on an individual’s cognitive functions such as decision-making and impulse control, leading to a vicious cycle that can be difficult to break. According to the experts, the brain’s immune system may be involved in this process, which can have long-lasting effects, making heavy drinkers more likely to continue to drink. 

The researchers investigated the link between alcohol consumption and the immune signaling molecule interleukin 1β (IL-1β) in mice models. By comparing the brains of alcohol-dependent mice to those of mice with moderate or no alcohol consumption, they found that the former had twice as many cells producing IL-1β in the medial prefrontal cortex, a part of the brain that regulates cognitive function. In alcohol-dependent mice, IL-1β increased inflammation and the release of gamma-aminobutyric acid (GABA), which regulates neural activity in the brain. These changes were found to persist even when the mice no longer consumed alcohol.

The neuroimmune system, a specialized immune system for the brain, is responsible for eliminating pathogens and promoting proper healing after injury and healthy brain function. Although alcohol activates the neuroimmune system only “mildly,” changes from this mild activation can accumulate over time as an individual drinks more heavily and more often. Thus, heavy and prolonged alcohol use will likely affect neuroimmune signaling, which can lead to the cognitive decline observed in people suffering from alcohol use disorder (AUD).

“So, in the healthy brain, the neuroimmune system will resolve the ‘mild’ problem and the neurons will return to a healthy state,” said study lead author Florence Varadoyan, a psychologist at Binghamton. “In the chronic ethanol brain, there will be ongoing inflammation that is likely an exaggerated response to the size of the initial problem. This will likely lead to more widespread neuron damage that isn’t recoverable.”

These findings could lead to improved treatments for substance abuse, particularly since drugs that block the activity of IL-1β are already approved by the U.S. Food and Drug Administration (FDA) to treat rheumatoid arthritis and other inflammatory conditions. “We plan to follow up on this study with more work on exactly how targeting specific components of the IL-1β pathway might be useful in treating alcohol use disorder,” concluded senior author Marisa Roberto, a neuroscientist at the Scripps Research Institute.

The study is published in the journal Brain, Behavior, and Immunity.

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By Andrei Ionescu, Earth.com Staff Writer

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