The Bronchoalveolar Lavage Proteome- Phenotypic associations to smoking and divergence towards development of COPD

Proteomic analysis of bronchoalveolar lavage (BAL) fluid from smokers at risk of developing chronic obstructive pulmonary disease (COPD) and never smokers is described. COPD is currently the world's fourth leading cause of death and its prevalence is increasing. The leading cause of COPD is smoking and an estimated 600 million people in the world suffer from COPD which makes it the world's most common chronic disease. The aim of this thesis was to explore and characterize the BAL proteome of never smokers and smokers. The hypotheses were that the BAL proteome reflect smoking habits in subjects, and that smokers susceptible to COPD development have a specific proteome. In order to relate the measurement of protein expression with clinical phenotypes we have developed and utilized an interdisciplinary toolbox that includes protein separation (two-dimensional gel electrophoresis and liquid chromatography), mass spectrometry identification and statistical methods for multivariate analysis. The study material used in this thesis consisted of age matched men all born in 1933, living in one city differing by lifelong smoking history. These were compared by clinical function measurements and histological assessment at the same relative time points. A follow up study after 6-7 years identified a group of subjects who had progressed to COPD GOLD stage 2. Those with COPD shared a distinct protein expression profile in the baseline BAL sample which could be identified using multivariate analysis. This pattern was not observed in BAL samples of asymptomatic smokers free of COPD at the 6-7 year follow-up. The results suggest that specific patterns of protein expression occur in the airways of smokers susceptible to COPD disease progression, before the disease is clinically measurable.