Fig. 2.

Total, active and nuclear β-catenin staining is increased in the COPD bronchial epithelium.

a) Total β-catenin staining in the airway epithelium from non-smokers and smoker controls and COPD patients (GOLD classification from 1 to 4 according to the spirometric severity of the disease), in terms of percentage of positive area.

b) Correlation between total β-catenin in terms of percentage of positive area, and disease severity evaluated by the FEV1 (% of predicted values).

c) Representative picture of control and very severe COPD airway epithelium, stained for total β-catenin.

d) Active β-catenin staining was also increased in (very) severe COPD epithelium as compared with non-smokers and control smokers, in terms of percentage of positive area.

e) Correlation between active β-catenin in terms of percentage of positive area, and disease severity evaluated by the FEV1.

f) Representative picture of control and very severe COPD airway epithelium, stained for active β-catenin.

g-h) The percentage of positive active β-catenin nuclei was higher in the epithelium of (very) severe COPD patients as compared with non-smokers and control smokers (g), and correlated with COPD severity witnessed by the FEV1 (h).

*, **, ***, **** indicate p-values of less than 0•05, 0•01, 0•001, and 0•0001, respectively (analysed using the Kruskal-Wallis test followed by Dunn's post-hoc test). Bars indicate median ± interquartile range. COPD, chronic obstructive pulmonary disease; FEV1, forced expired volume in 1 second; NS, non-smokers; Smo, smokers; PV, predicted values. Scale bars, 50 µm.