cystic fibrosis

Infection comes first in cystic fibrosis

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New research suggests infection happens before inflammation in the lungs of patients with cystic fibrosis. “Knowing that infection is first suggests that if we can prevent or fight infection, then that might delay or prevent the lung disease in people with CF,” says David Stoltz. Above, bacteria in the airway of a pig lung. The team generated the pig model in the hope that it would more closely mimic the human disease. (Courtesy: U. Iowa)

U. IOWA (US)—A new study appears to answer a long-standing “chicken and egg” question about cystic fibrosis and lung disease: Which comes first—infection or inflammation?

“Using our model we are beginning to answer that question, and it looks like infection does precede inflammation,” says David Stoltz, assistant professor of internal medicine at the University of Iowa and lead author of a study published in the journal Science Translational Medicine.

“The importance of that finding is that it could dictate what types of therapy we might use. Knowing that infection is first suggests that if we can prevent or fight infection, then that might delay or prevent the lung disease in people with cystic fibrosis (CF).”

The finding supports early and aggressive treatment of lung infections in children with CF, adds Stoltz.

The new experimental model that Stoltz and colleagues at the University of Missouri used were pigs with a CF-causing gene mutation. The team generated the pig model in the hope that it would more closely mimic the human disease than mouse models do.

In the first six months of life, the CF pigs developed lung disease typical of what is seen in humans, including infection in the lungs, inflammation, and accumulation of mucus in the airways, which is a significant problem for patients with CF.

“This is a really great example where the pig serves as a model for what happens in the human, and the pig reacts to this disease in nearly the same way,” says Randall Prather, distinguished professor of reproductive biotechnology at the University of Missouri.

“In contrast, when you use mice, they don’t get the lung disease that is common in patients with cystic fibrosis.”

The team also found that the lungs of newborn CF pigs tended to be infected with more bacteria than lungs of control pigs, and within a few hours of birth, they showed signs that their lungs are less able to get rid of bacteria.

This problem might represent an initial step in the disease process that results in chronic lung infection in CF.

“Our new model will help us understand the mechanisms of lung disease in humans with CF,” Stoltz says.

“It also provides a unique opportunity to test different therapies starting at a very early stage of the disease—much earlier than we can in humans with CF—and maybe to target preventive therapies that might help delay or even prevent the type of lung disease that affects people with CF.”

The study was funded in part by grants from the National Institutes of Health and the Cystic Fibrosis Foundation.

More University of Iowa news: http://news.uiowa.edu/

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