Acid-suppressing drugs may blunt corticosteroid response in asthma patients

Last Updated: 2017-05-18

By Reuters Staff

NEW YORK (Reuters Health) - Acid-suppression medications are associated with changes in the airway microbiome in patients with asthma, and these changes may affect corticosteroid response, new research suggests.

Gastroesophageal reflux disease (GERD) often co-occurs with difficult-to-treat asthma, and patients with refractory asthma and cough are frequently treated with proton pump inhibitors (PPIs) and histamine receptor 2 antagonists (H2 blockers), Dr. Elena Goleva of National Jewish Health in Denver and colleagues note in the Journal of Allergy and Clinical Immunology, online May 3. Both esophagitis and GERD are associated with changes in esophageal microbiota, they add.

Dr. Goleva and her team had previously shown that patients with corticosteroid-resistant (CR) asthma had expansion of gram-negative bacteria in their airways, and that pathogenic bacteria blocked corticosteroid response in airway macrophages and peripheral blood monocytes from patients with asthma.

In the new study, the researchers compared airway microbiomes in six CR patients on acid-suppressing medications and nine patients with CR asthma who had not taken PPIs or H2 blockers.

The patients on acid-suppressing medications had a higher percentage of Firmicutes, mainly due to increases in Streptococci and reductions in Proteobacteria. S. mitis was the most predominant type of Streptococci, found in all six patients, followed by S. pseudopneumoniae, present in two patients. Both strains are opportunistic pathogens related to S. pneumoniae.

Bronchial epithelial cells incubated with the pathogenic bacteria had a lower in vitro response to corticosteroids, while incubating cells with commensal Streptococcus strains did not reduce corticosteroid sensitivity, the researchers found.

“The expansions of Streptococci may occur due to various factors, that is, aerodigestive exchanges due to GERD, the direct response to acid suppression medications and/or due to the changes in bacterial environment that provide favorable conditions for Streptococci growth in the airways,” the authors write.

“We therefore suggest that comprehensive evaluation of aerodigestive interactions in severe asthma should include the potential role of acid suppression medications (PPIs and H2 blockers) and their effects on the esophageal and lower airway microbiome as it relates to corticosteroid response,” they conclude.

Dr. Goleva was not available for an interview by press time.

SOURCE: http://bit.ly/2pNKBsg

J Allergy Clin Immunol 2017.