Chronic alcohol abuse causes a profound deficiency of the antioxidant
glutathione in the lungs, generating a marked susceptibility to
serious lung diseases, according to research at the School of Medicine
and the VA Medical Center.
Lowered glutathione levels can be as deadly to the lungs of alcohol
abusers as alcohol itself can be to their livers and other organs,
according to David Guidot, associate professor of medicine. Guidot
explained how glutathione depletion affects the lungs at the Experimental
Biology 02 meeting in New Orleans on April 24.
Until six years ago, when Emory scientist Marc Moss first identified
the connection between alcohol abuse and lung damage, scientists
had not associated the two, even though alcohols ill effects
on the liver, brain and other organs were well recognized.
We now know that as many deaths occur every year from alcohol
abuse related to lung injury as occur from alcohol abuse and liver
disease or alcohol abuse and traffic accidents, Guidot said.
Scientists previously had not focused on the connection between
alcohol and lung disease because the causal relationship is indirect,
unlike the direct effect of alcohol on the liver, Guidot explained.
He began studying the effects of glutathione depletion on the lungs
while reviewing the mechanisms of alcohol toxicity in other organs.
The body manufactures glutathionea strong antioxidant moleculefrom
amino acids, which are the building blocks of proteins. Individuals
with reasonably good diets maintain an adequate supply of glutathione,
which constantly is being used up and replenished.
Although glutathione is manufactured in a variety of organs and
tissues, including the liver, the lungs are particularly dependent
on glutathione for protection from oxidative damage, especially
in the small airways where breathing takes place. The lack of glutathione
in the lungs leads to a variety of abnormalities, said Guidot, including:
damage to the epithelial cells and fluid that line the lungs; changes
in the barrier function of lung cells; and increased susceptibility
to apoptosis, or cell death in the lungs.
These abnormal cell changes caused by chronic alcohol abuse leave
the lung vulnerable to injury when a serious illness such as sepsis
or pneumonia occurs. Heavy drinking and its relationship to
lung disease is like driving on the highway without a seat belt,
Guidot said. Its risky behavior, but it doesnt
cause injury unless you get in an accident. Alcohol doesnt
cause lung disease unless you get sick; then the lungs are less
able to respond to the challenges of infection.
The cure for alcohol-induced lung damage is not as simple as just
taking extra doses of glutathione, Guidot added, because an acute
lung infection often is the first sign of damage.
If your house is on fire, its too late to install a
smoke detector, he said. Glutathione depletion cannot be quickly
reversed. Only after the immediate illness is addressed can physicians
consider treating a patient for alcoholism and consider long-term
By studying the mechanisms of glutathione damage, Guidot and his
colleagues hope to design more effective therapies for preventing
and treating the effects of chronic alcohol abuse.