Scientists uncover liver's role in preventing dissemination of lung infection

Researchers at Boston University School of Medicine (BUSM) have discovered the regulation and functional significance of the acute phase response during a lung infection. The findings, which will be published in the May edition of the Journal of Clinical Investigation, demonstrate that the liver responds in order to increase defenses in the blood that prevent localized infections from spreading throughout the body.

The study was led by Joseph P. Mizgerd, Sc.D., professor of medicine, microbiology and biochemistry at BUSM, and Lee J. Quinton, PhD, assistant professor of medicine and pathology at BUSM.

The acute-phase response is an where dozens of blood proteins change in concentration due to physiological stresses such as infection, inflammation and injury. The change in concentrations of these proteins, such as C-reactive protein, can be measured in the blood and can indicate risk or progression of disease.

"While the acute-phase response was discovered in 1930, the mechanism and meaning behind the changes in certain blood protein concentrations are not well understood," said Mizgerd, who also is the director of the Pulmonary Center at BUSM.

In this study, the researchers mutated two transcription factor genes, STAT3 and RelA, in . These cells, called hepatocytes, generate the blood proteins that change during an acute-phase response. Prior to infection, these mutations had no measurable effects. In response to pneumonia, which normally triggers the acute phase response, these mutations completely prevented such changes in the blood proteins. Thus, the acute-phase response was specifically inhibited.

The inability of the to change led to those bacteria escaping from the lungs into the blood, which were then attacked ineffectively by the trying to destroy them. This exacerbated the infection, allowing it to spread to the blood and other organs.

"For the first time, we have shown the acute-phase response that occurs as a result of a lung infection triggers the liver to mount bloodstream defenses, preventing the infection from spreading throughout the body," said Mizgerd.

add to favorites email to friend print save as pdf

Related Stories

Key to out-of-control immune response in lung injury found

Aug 16, 2007

Researchers at the University of Illinois at Chicago College of Medicine have discovered how a protein modulates the inflammatory response in sudden, life-threatening lung failure. The protein's previously unknown role is ...

Recommended for you

Diet affects men's and women's gut microbes differently

16 hours ago

The microbes living in the guts of males and females react differently to diet, even when the diets are identical, according to a study by scientists from The University of Texas at Austin and six other institutions published ...

Researchers explore what happens when heart cells fail

17 hours ago

Through a grant from the United States-Israel Binational Science Foundation, Biomedical Engineering Associate Professor Naomi Chesler will embark upon a new collaborative research project to better understand ...

Stem cells from nerves form teeth

19 hours ago

Researchers at Karolinska Institutet in Sweden have discovered that stem cells inside the soft tissues of the tooth come from an unexpected source, namely nerves. These findings are now being published in the journal Nature and co ...

User comments