International Journal of COPD (Feb 2021)
Small Airways Disease, Biomarkers and COPD: Where are We?
Abstract
Priyamvada S Chukowry,1 Daniella A Spittle,2 Alice M Turner3 1Respiratory Research Department, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK; 2Institute of Inflammation and Ageing, University of Birmingham, Birmingham, B15 2TT, UK; 3Institute for Applied Health Research, University of Birmingham, Birmingham, B15 2TT, UKCorrespondence: Alice M TurnerInstitute for Applied Health Research, University of Birmingham, Birmingham, B15 2TT, UKTel +44 0121 3713885; +44 07825683519Email [email protected]: The response to treatment and progression of Chronic Obstructive Pulmonary Disease (COPD) varies significantly. Small airways disease (SAD) is being increasingly recognized as a key pathological feature of COPD. Studies have brought forward pathological evidence of small airway damage preceding the development of emphysema and the detection of obstruction using traditional spirometry. In recent years, there has been a renewed interest in the early detection of SAD and this has brought along an increased demand for physiological tests able to identify and quantify SAD. Early detection of SAD allows early targeted therapy and this suggests the potential for altering the course of disease. The aim of this article is to review the evidence available on the physiological testing of small airways. The first half will focus on the role of lung function tests such as maximum mid-expiratory flow, impulse oscillometry and lung clearance index in detecting and quantifying SAD. The role of Computed Tomography (CT) as a radiological biomarker will be discussed as well as the potential of recent CT analysis software to differentiate normal aging of the lungs to pathology. The evidence behind SAD biomarkers sourced from blood as well as biomarkers sourced from sputum and broncho-alveolar lavage (BAL) will be reviewed. This paper focuses on CC-16, sRAGE, PAI-1, MMP-9 and MMP-12.Keywords: spirometry, targeted treatment, normal aging, pathological process
