Fat damages the lungs of heavy drinkers

June 30, 2014

(PHILADELPHIA) - Heavy drinking damages the body in many ways. In addition to liver failure, alcoholics are at a much greater risk of developing pneumonia and life threatening acute respiratory distress syndrome (ARDS), for which there is no treatment. Researchers suspect that alcoholics are more susceptible to these lung diseases because the immune system in the lung is no longer strong enough to protect from infection and damage, but, it had been unclear why the immune system in the lung fails.

Now, researchers at Thomas Jefferson University have discovered that one of the keys to immune system failure in the lung is a build-up of fat, a finding that offers both a novel explanation for lung disease and offers the possibility of a new treatment.

"We call it the alcoholic fatty lung," says lead researcher Ross Summer, M.D., an associate professor in the division of Pulmonary and Critical Care Medicine and the Center for Translational Medicine at Thomas Jefferson University. "The fat accumulation in the lungs mimics the process that causes fat to build up and destroy the liver of alcoholics," he adds.

When people drink, liver cells begin to produce fat, possibly as a defense mechanism against the toxicity of the alcohol. Over extended and frequent alcohol exposure, the fat accumulates and heavy drinkers develop so called "fatty liver disease". The fat build at first impairs liver function but can also cause scarring that eventually leads to liver failure.

The lungs, however, also contain a subpopulation of cells that make fat. Surfactant producing cells expel a fatty secretion onto the inner lining of the lung to keep the airways properly lubricated during breathing. Dr. Summer and colleagues wondered whether these surfactant cells might behave in a similar way to liver cells after extended alcohol exposure by also accumulating fat.

After extended exposure to alcohol in rats, the researchers noticed that surfactant cells increased their production of triglycerides by 100 percent and free fatty acids by 300 percent, compared to rats fed an non-alcoholic diet with the same number of calories. The researchers also noticed fat-up not only in surfactant cells but also in lung macrophages, which are immune cells that normally engulf and digest bacteria or sick cells in the lung.

"It's likely that the macrophages try to engulf the excess fat in order to protect the cells in the lung, but in doing so, they become less effective sentinels against infection and disease," said Summer. Indeed, the researchers showed that these fat-exposed macrophages were much less effective at killing bacteria than normal macrophages.

If the same process can be observed in humans - an avenue of research that Dr. Summer is currently exploring - it would suggest that that lipid lowering drugs (a class of drugs called fibrates) could be useful in treating alcohol-related pneumonia and in preventing the development of ARDS.
-end-
Research was supported by funding from the National Institutes of Health (NIH) R01HL105490 and R37 AA11290

The authors report no conflict of interest.

For more information, contact Edyta Zielinska, 215-955-5291, edyta.zielinska@jefferson.edu.

About Jefferson

Thomas Jefferson University (TJU), the largest freestanding academic medical center in Philadelphia, is nationally renowned for medical and health sciences education and innovative research. Founded in 1824, TJU includes Jefferson Medical College (JMC), one of the largest private medical schools in the country and ranked among the nation's best medical schools by U.S. News & World Report, and the Jefferson Schools of Nursing, Pharmacy, Health Professions, Population Health and the Graduate School of Biomedical Sciences. Jefferson University Physicians is TJU's multi-specialty physician practice consisting of the full-time faculty of JMC. Thomas Jefferson University partners with its clinical affiliate, Thomas Jefferson University Hospitals.

Article reference: F. Romero, et al., "Chronic alcohol ingestion in rats alters lung metabolism, promotes lipid accumulation, and impairs alveolar macrophage functions," AJRCMB, DOI: 10.1165/rcmb.2014-0127OC, 2014.

ESZ 6/30/2014

Thomas Jefferson University

Related Immune System Articles from Brightsurf:

How the immune system remembers viruses
For a person to acquire immunity to a disease, T cells must develop into memory cells after contact with the pathogen.

How does the immune system develop in the first days of life?
Researchers highlight the anti-inflammatory response taking place after birth and designed to shield the newborn from infection.

Memory training for the immune system
The immune system will memorize the pathogen after an infection and can therefore react promptly after reinfection with the same pathogen.

Immune system may have another job -- combatting depression
An inflammatory autoimmune response within the central nervous system similar to one linked to neurodegenerative diseases such as multiple sclerosis (MS) has also been found in the spinal fluid of healthy people, according to a new Yale-led study comparing immune system cells in the spinal fluid of MS patients and healthy subjects.

COVID-19: Immune system derails
Contrary to what has been generally assumed so far, a severe course of COVID-19 does not solely result in a strong immune reaction - rather, the immune response is caught in a continuous loop of activation and inhibition.

Immune cell steroids help tumours suppress the immune system, offering new drug targets
Tumours found to evade the immune system by telling immune cells to produce immunosuppressive steroids.

Immune system -- Knocked off balance
Instead of protecting us, the immune system can sometimes go awry, as in the case of autoimmune diseases and allergies.

Too much salt weakens the immune system
A high-salt diet is not only bad for one's blood pressure, but also for the immune system.

Parkinson's and the immune system
Mutations in the Parkin gene are a common cause of hereditary forms of Parkinson's disease.

How an immune system regulator shifts the balance of immune cells
Researchers have provided new insight on the role of cyclic AMP (cAMP) in regulating the immune response.

Read More: Immune System News and Immune System Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.