Cystic fibrosis disease severity correlates with plasma levels of desmosine and isodesmosine, biomarkers of elastin degradation

Cystic fibrosis (CF) patients have elevated plasma desmosine and isodesmosine (DI) levels compared with healthy subjects. a) Patient demographics. ^#: denotes a statistically significant difference between groups. b) DI levels were determined in plasma from 12 healthy and 12 CF patients. Box plots represent mean±sem, where each measurement was performed three times on each sample. Groups were compared by the D'Agostino and Pearson omnibus normality test and by Mann–Whitney tests. c) Plasma DI levels were correlated with the frequency of disease exacerbations in the past 12 months. d) DI levels were examined in plasma from patients colonised by Staphylococcus aureus (S. aureus), Pseudomonas or both. e) Forced expiratory volume in 1 s (FEV₁) (% predicted) and f) FEV₁ (L) levels were plotted against plasma DI levels in CF patients. The R² and p-value is shown for each correlation, determined by linear regression analysis. All analysis was performed using GraphPad Prism Software (Version 5 for Mac OS X; GraphPad Software, La Jolla, CA, USA). BMI: body mass index.