The role of metabolomics in chronic obstructive pulmonary disease: from analytic techniques to clinical applications

Chronic obstructive pulmonary disease (COPD) is a complex, progressive inflammatory disorder characterized by airflow limitation and respiratory symptoms. Its heterogeneity is manifested at etiological, pathological and clinical levels, and leads to different phenotypes: chronic bronchitis, emphysema, asthma-COPD overlap, frequent exacerbator and eosinophilic phenotypes. COPD is also associated with systemic manifestations including cardiovascular diseases, muscle dysfunction, osteoporosis and mental-health issues, which require a comprehensive management approach. Key risk factors are tobacco smoke and air pollution, both of which induce oxidative stress and airway remodeling. Although there is still no definitive cure for COPD, an early diagnosis and a multidisciplinary treatment are essential to prevent or slow the disease progression and reduce the mortality rate. Molecular biomarkers, particularly those identified through metabolomics, show promise for early detection, phenotyping and precision therapies. Challenges in biomarker discovery include specimen variability and stability. Overall, metabolomics provides valuable insights into COPD's molecular pathways, supporting improved diagnosis, prognosis and tailored treatments. In this tutorial, we will explore metabolomics findings from different COPD matrices and their clinical implications for diagnosis, treatment and prognosis.