There is a severity dependent increase in the size but not the absolute number of interalveolar pores of Kohn in COPD. In addition, the pore size shows important correlations with pulmonary function testing. https://bit.ly/3HL1GJ8

The authors would like to acknowledge ACAM, the microscopy core facility of the University of Antwerp, for the use of their microscopy facilities. The authors thank Els Goeman, Annemie Van Den Broeck and Joke De Raedemaecker (all from the University of Antwerp) for their excellent technical support; Paul Van Schil and Annelies Janssens (University Hospital Antwerp), Halil Sirimsi and Wim Callebaut (General Hospital Voorkempen), Itte Dobbeleir and Yves Mentens (General Hospital Herentals), Carolien De Tollenaere (General Hospital Herentals), and Bruno De Belie and Erika Saenen (General Hospital Rivierenland) for their help in recruiting patients for this study; the pathology residents at University Hospital Antwerp for their help in the processing of the samples; and Joaquim Sanctorum from imec-Visionlab of the University of Antwerp for help with the micro-CT scanning. In addition, the authors would like to thank Sofie Thys (University of Antwerp) for excellent technical assistance with the SEM preparation.

Ethics statement: This study has been approved by the ethical committee of the Antwerp University Hospital and all patients provided written informed consent (approval number: EDGE 001693).

Conflicts of interest: The authors have no potential conflicts of interest to disclose.

Support statement: Supported by University Hospital Antwerp, a fund from the Bijzonder Onderzoeksfonds (46818 and 46822 to J.M.H. Hendriks and T.S. Lapperre). This research was also funded by Chiesi Pharmaceuticals. The underlying study represents an investigator-initiated trial. Chiesi Pharmaceuticals was not involved in the development, execution and analysis of the trial. The manuscript was reviewed before submission by Chiesi Pharmaceuticals. The authors themselves did not receive any financial support with regards to the study.