Intake of alcohol likely to increase Alzheimer’s risk

Washington, June 5: Alcohol consumption impedes the ability of brain cells to keep clear of amyloid plaques, and may contribute to the development of Alzheimer’s disease, according to a study.

Researchers from the University of Illinois at Chicago, US found that some of the genes affected by alcohol and inflammation are also implicated in processes that clear amyloid beta — the protein that forms globs of plaques in the brain and which contributes to neuronal damage and the cognitive impairment associated with Alzheimer’s.

Previous studies investigating the effects of alcohol consumption on Alzheimer’s disease have been controversial - some have indicated that alcohol has a protective effect, while others have pointed to a deleterious role for alcohol in the development of the neurocognitive disease.

Recent research has suggested that alcohol consumption, and its impact on the immune system and inflammation in the brain, may be the vehicle through which alcohol might exert its influence on the development of Alzheimer’s disease.

However, no previous studies have directly evaluated which genes are affected by alcohol in cells in the brain involved in protecting against Alzheimer’s disease. The cell- based study suggests that alcohol may impede the clearance of amyloid beta in the brain. Douglas Feinstein, a professor at the University of Illinois, and colleagues wanted to determine which genes were affected by both alcohol and high levels of inflammation in microglial cells.

These are cells that support neural cells in the brain and elsewhere in the body.

One of their functions is to engulf and digest the amyloid beta protein plaques characteristic of Alzheimer’s disease in a process known as phagocytosis. Microglial cells are also known to express high levels of inflammatory markers due to chronic alcohol exposure. The researchers exposed rat microglial cells to alcohol, pro- inflammatory chemicals called cytokines, or alcohol and cytokines in the lab for 24 hours, and then looked at changes in gene expression under each condition. They also looked at the impact of alcohol exposure on the cells’ ability to engulf amyloid beta.

The team found that gene expression was altered for 312 genes under the alcohol condition; for 3,082 for the proinflammatory condition, and 3,552 for the alcohol and pro- inflammatory condition.