Washington, June 18 : You might not just realize this while downing a mug of chilled beer on a summer afternoon, but a new study has revealed that too much alcohol can cause permanent damage to brain.
The study has shown that too much alcohol can also cause brain injury and degeneration by inhibiting insulin and insulin-like growth factor (IGF)
With the help of postmortem human brain tissue, researchers showed that chronic alcohol abuse can decrease levels of genes needed for brain cells to respond to insulin/IGF, leading to neurodegeneration similar to that caused by Type 2 diabetes mellitus.
"Insulin is one of the most important hormones in the body," said Suzanne de la Monte, professor of pathology/ neuropathology and clinical neuroscience at Rhode Island Hospital and the Warren Alpert School of Medicine at Brown University.
"It has many functions, including regulation of metabolism. Cells throughout the body depend upon insulin just to stay alive and carry out 'ordinary daily functions. The best known diseases associated with abnormalities in insulin's availability or actions are Type 1 and Type 2 diabetes," she added.
The study showed that in chronic alcoholics' brains, there was significant insulin and IGF resistance in those regions known to be highly sensitive to alcohol's toxic effects.
"Alcohol is a toxin that clearly can injure or kill brain cells," de la Monte said.
"Fortunately, alcohol has to pass through the gastrointestinal tract and liver where enzymes detoxify alcohol, and consequently reduce the levels that reach the brain.
"However, in either high concentrations, or at lower levels over a longer period of time, alcohol will dissolve some of the lipid in the cell's membrane," she added.
During the study, researchers examined brain tissue from six male chronic alcoholics with a mean age of 57.7 years, and six male "controls" without alcoholism with a mean age of 57.5 years.
Two brain regions were selected for study - the cerebellar cortex, which sends information to the muscles causing them to move and cingulate gyrus in the frontal lobe, involved with emotion formation and processing, learning, and memory. These were major targets of alcohol's neurotoxicity.
The results showed that in chronic alcoholics' brains, there was significant insulin and IGF resistance in those regions known to be highly sensitive to alcohol's toxic effects.
De la Monte added that the insulin resistance their study found was quite similar to what happens in Type 2 diabetes, which means that alcoholic brain disease may be treatable in part by use of drugs that make brain cells more responsive to insulin and IGF.
The study will be published in the September issue of Alcoholism: Clinical and Experimental Research and are currently available at OnlineEarly.