Pitt Professor Aids Development of Treatment for Collapsed Lungs

PITTSBURGH—Thousands of adults suffer from collapsed lungs each year, caused by a lack of lung surfactant, a vital soapy substance that permits the lungs to expand normally. Conventional treatment is forced mechanical ventilation, which can stabilize the lungs until surfactant performance improves, but use of these ventilators results in a 36 to 52 percent mortality rate.

University of Pittsburgh chemist Heidi Warriner examined the chemical structure of replacement surfactants—an alternative to ventilators—in different environments to determine which surfactant is most effective in adult lungs. Warriner will present her research March 31 at the American Chemical Society's 227th national meeting in Anaheim, Calif.

"Our research team has shown that adding small amounts of polyethylene glycol (PEG), a low molecular-weight polymer, to commercially available replacement surfactants can substantially increase their effectiveness," said Warriner, assistant professor in the Department of Chemistry.

"To understand the mechanism behind this improvement, we're taking surfactants that respond well to PEG and trying to see what happens to their bulk structure," said Warriner. "PEG is a cheap additive, so it would be great if PEG could form part of a new surfactant that would be substantially more effective in adult patients."

Warriner placed surfactant in solution with various polymers, including PEG, on a simulated lung surface. She examined the structure of the result with a small-angle

X-ray scattering machine, which can be used to look at the structures of surfactant assemblies.

Acute Respiratory Distress Syndrome, which can cause collapsed lungs, occurs when adults experience such trauma to the lungs as pneumonia or breathing chemicals. Trauma causes the lungs to overproduce serum proteins, which reduce the effectiveness of surfactant in the lung.

Serum proteins are present in small amounts in a healthy lung, but in a damaged lung, serum protein concentration increases and competes with surfactant for the surface area of the lung. Polymers such as PEG can squeeze water out of the surfactant, making it more compact and possibly better able to hold on to the lung surface despite the overabundance of serum proteins.

Warriner collaborated with groups headed by Joseph Zasadzinski, professor of chemical engineering at the University of California, Santa Barbara, and H. William Taeusch, professor and vice chair of pediatrics at the University of California, San Francisco.

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