Airway remodelling augmented in patients with asthma COPD overlap (ACO) compared to asthma and COPD

Abstract

Background: Management of ACO is clinically challenging due to insufficient evidence on pathological changes in these patients.

Aim: To evaluate large airway remodelling changes in patients with ACO compared to asthma, COPD ex-smokers (ES) and current smokers (CS), non-smoking normal controls (NC), and normal lung function smokers (NLFS).

Methods: Endobronchial biopsy tissue from 12 ACO, 14 asthmatics, 12 COPD‑ES, 11 CS, 28 NC, and 13 NLFS were stained with Masson’s trichrome. Epithelial and goblet cells/mm reticular basement membrane (RBM); total lamina propria (LP) cells/mm2 up to 120 µm deep were enumerated for the area surveyed; RBM, epithelial, and smooth muscle (SM) thickness were analysed using imaging software ImageProPlus V7.0.

Results: Compared to asthma and COPD, ACO showed differential remodelling pattern. The RBM was significantly thicker in ACO than asthmatics (p <0.04), NC (p <0.0001), NLFS (p <0.03), but not COPD ES (p 0.2316)/CS (p 0.2599). Goblet cells were significantly higher in ACO than COPD-ES (p <0.006) and CS (p <0.04). Further in ACO, RBM cells were higher than the NC (p <0.004), NLFS (p <0.0001), COPD-ES (p <0.0007), and CS (p <0.003), however, did not differ from asthmatics (p 0.4252). LP cells in ACO were significantly higher than COPD-CS (p <0.04); lower than the asthmatics (p <0.02). Finally, SM thickness was significantly lower in ACO than asthmatics (p <0.02), CS (p <0.05), and NLFS (p <0.02). No epithelial changes were seen in ACO as compared to other groups.

Conclusions: Our findings suggest that ACO patients had severe tissue remodelling changes than asthmatics and COPD patients.