Research Unveils the Brain's Rewiring Due to Alcohol Abuse

Alcohol abuse can lead to numerous health issues, and recent research has discovered that it also alters brain function. A study published in Progress in Neurobiology on November 13, 2020, revealed that alterations in the cellular activity of the amygdala could lead to alcohol addiction. The amygdala, an almond-shaped area deep in the brain, is responsible for regulating emotions, behavior, and motivation. Disruption in its anti-inflammatory mechanisms and cellular activity may cause substance addictions.

Marisa Roberto, Ph.D., a professor at Scripps Research's Department of Molecular Medicine, along with her team, investigated these changes in the amygdala. They uncovered the process by which alcohol abuse restructures the brain, particularly affecting the amygdala. Their experiments with mice demonstrated a method to reverse this process and curb excessive alcohol consumption, offering hope for new alcohol abuse treatments.

HOW ALCOHOL CHANGES THE BRAIN

"Chronic alcohol exposure impairs brain immune cells vital for neuron health," states Reesha Patel, Ph.D., a postdoctoral fellow in Roberto's lab and the study's lead author. "The damage incurred promotes anxiety and alcohol consumption, potentially leading to alcohol use disorder." The research centered on a brain immune protein known as Interleukin 10, or IL-10, which has a strong anti-inflammatory effect and regulates the immune system's response to threats. IL-10 also mitigates inflammation from brain injuries or diseases like stroke or concussion. Chronic alcohol abuse has been linked to reduced IL-10 levels in the brain.

Mice with prolonged alcohol exposure showed significantly lower IL-10 levels in the amygdala, resulting in improper neuron firing and heightened alcohol intake. However, enhancing IL-10 signaling in the brain reversed these adverse effects of excessive alcohol consumption, notably reducing anxiety and the inclination to drink.

"Inflammatory immune responses in the brain play a significant role in the onset and persistence of alcohol use disorder," Roberto explains. "More crucially, our findings offer a new avenue for therapeutic intervention through anti-inflammatory mechanisms."

Alcohol use disorder impacts approximately 15 million Americans, with limited treatment options available. Fortunately, this study could pave the way for additional therapies for those struggling with alcoholism. The focus is on enhancing anti-inflammatory processes in the brain since increased inflammation seems to aggravate the condition.

KNOW THE MAIN RED FLAGS FOR ALCOHOL USE DISORDER (AUD)

According to the Mayo Clinic, key indicators of alcohol use disorder include:

• Inability to limit alcohol consumption
• Unsuccessful efforts to reduce drinking, despite wanting to
• Spending a lot of time drinking, getting alcohol, or recovering from its effects
• A strong craving or compulsion to drink
• Neglect of responsibilities at work, school, or home due to drinking
• Continued alcohol use despite ongoing physical, social, or psychological issues
• Abandonment of social, occupational, or recreational activities
• Consuming alcohol in dangerous situations, such as while driving or operating machinery
• Developing a tolerance to alcohol, requiring more to achieve the same effect
• Withdrawal symptoms like nausea, sweating, and shaking when not drinking, or drinking to relieve these symptoms

HEAVY DRINKING CAN CAUSE THE FOLLOWING HEALTH PROBLEMS OVER TIME:

• Liver disease. Heavy drinking can cause fatty liver disease, inflammation of the liver, and cirrhosis.
• Digestive problems. Alcohol abuse can lead to inflammation of the stomach lining, as well as ulcers. It can also cause malabsorption of necessary nutrients. Furthermore, it may cause pancreatitis (inflammation of the pancreas).
• Heart problems. Excessive drinking can lead to high blood pressure and eventually cause a heart attack or stroke. Just one episode of heavy drinking can cause heart arrhythmia.
• Worsens diabetes. Alcohol may cause low blood sugar because it disrupts the release of glucose from your liver. If you have diabetes and take insulin to lower your blood sugar, this can have dangerous implications.
• Neurological complications. Alcohol abuse can damage your nervous system, causing numbness and pain in your extremities, memory problems, dementia, and difficulty thinking clearly.
• Weakened immune system. Excessive alcohol intake can make it harder for your body to fight off diseases due to disruption in gut bacteria.
• Increased risk of cancer. Long-term, excessive alcohol use can increase the risk of many cancers, including mouth, throat, liver, esophagus, colon, and breast cancers.

FURTHER FINDINGS FROM THE STUDY

In the referenced study, Roberto's team worked with Silke Paust, Ph.D., an associate professor in the Department of Immunology and Microbiology. They discovered that chronic alcohol use in mice led to increased levels of microglia and T-regulatory cells, which produce the anti-inflammatory protein IL-10. Although there was an overall increase in IL-10 levels in the mice's brains, the amygdala had significantly lower levels.

The amygdala, affected by alcohol abuse, showed impaired protein signaling, indicating a unique immune response to alcohol use disorder within this brain region.

The findings support Roberto's previous research linking microglia to alcohol abuse and suggest future studies will explore the interaction between IL-10 and amygdala neurons.

Excessive alcohol consumption not only harms the brain but also causes various health issues. Recent research indicates that it can disrupt brain function by reducing IL-10 in the amygdala, which governs emotions, motivation, and behavior—key factors in addiction. Scientists are optimistic that enhancing IL-10 signaling in the brain could counteract alcohol abuse.

Ongoing research aims to delve into the relationship between IL-10 and alcohol abuse, with the hope that future treatments will concentrate on anti-inflammatory agents and supplements.