New Cystic Fibrosis Research Focused On Pseudomonas Aeruginosa Tests, Treatment

Two new abstracts from the Journal of Cystic Fibrosis recently focused on the bacteria Pseudomonas aeruginosa (Pa) and sought to enhance knowledge of treating and diagnosing cystic fibrosis. Pa is highly relevant to cystic fibrosis, as it is the most common bacteria in the lungs of patients and leads to chronic infection and inflammation.

One group of researchers — which included investigators at University of Arizona in Tuscon, Case Western Reserve University School of Medicine, Seattle Children’s Research Institute, Seattle Children’s Hospital, University of Kentucky in Lexington, Mediagnost, and two international locations — reported on the usefulness of Pa serology as an early detector of infection in cystic fibrosis patients. The scientists proposed to use serology, the study of plasma serum and other bodily fluids, in addition to the standard method of respiratory culture.

Children from the Early Pseudomonal Infection Control Observational Study (EPIC OBS) were evaluated in addition to healthy controls. Serum from 582 patients and 94 control subjects was analyzed for antibodies against alkaline protease, elastase, and exotoxin A, all proteins elevated in the presence of Pa. After fitting mathematical models to the tests, the researchers found significant overlap in the levels of serum proteins among healthy controls, Pa-infected patients, and Pa-uninfected patients, indicating that Pa serology may not be useful in predicting Pa infection in cystic fibrosis children.

Although the first group may not have determined a new method of diagnosis, the second group of scientists — from Purdue University in Indianapolis, Indiana — may have found a new therapeutic approach to treat airway inflammation resulting from Pa colonization.

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The researchers suggest alginate lyase may be effective in battling effects of Pa infection. Alginate lyase is a protein that degrades alginate, a polysaccharide (complex sugar) produced by Pa that enables Pa to evade cystic fibrosis patients’ innate immune systems.

In the study, it was identified that over-production of alginate by mucoid Pa prevents apoptosed human peripheral blood monocyte-derived macrophages from being removed from the body by over 50% in both a time- and dose-dependent manner. Accumulation of dead cells and debris in the lungs can lead to inflamed airways, suggesting that by reducing alginate, inflammation may also be reduced. The researchers began to test this theory by applying alginate lyase and identifying a benefit on clearing macrophages in the scenario of exposure to over-producing alginate mucoid Pa.

Journal of Cystic Fibrosis provides a wealth of knowledge to scientists and patients alike. These two new studies of Pa make evident the fact that much has been learned about Pa infection in cystic fibrosis patients, but that knowledge can be expanded further to improve cystic fibrosis treatment and diagnosis.