Changes in urinary glutathione sulfonamide (GSA) levels between admission and discharge of patients with cystic fibrosis

Abstract

There is an urgent need to develop sensitive, non-invasive biomarkers that can track airway inflammatory activity for patients with cystic fibrosis (CF). Urinary GSA levels correlate well with GSA levels in BAL samples and other markers of neutrophilic inflammation, suggesting that this biomarker may be suitable for tracking disease activity in this population. We recruited 102 children (median 11.5 years-old) and 64 adults (median 32.5 years-old) who were admitted to hospital for management of an acute pulmonary exacerbation and/or eradication of infectious agents such as P. aeruginosa or S. aureus. Our aim was to explore how urinary GSA levels changed across admission timepoints. Urine samples were collected at admission and discharge, and GSA measured by liquid chromatography with mass spectrometry. Paired admission-discharge results were compared using Wilcoxon signed-rank test. Paired admission-discharge samples were available for 49 children and 60 adults. A statistically significant difference was observed between admission-discharge for children, but not for adults. Spearman’s correlation analysis identified a correlation between urinary GSA levels and age, sex, inflammatory markers, and P. aeruginosa infection for children only. Our preliminary findings suggest that urinary GSA is responsive to the resolution of an acute pulmonary exacerbation and therefore warrants further studies in this population.