Abstract
Introduction: Exhaled particles are formed in the small airways during airway re-opening after airway closure. Sampling and analysis of particles give the opportunity of measuring biomarkers noninvasively. Our aims were to investigate if biomarker concentrations (particle number, surfactant protein A (SP-A) and albumin) are influenced by sex, anthropometry and lung function, and to see if subjects with asthma differ from healthy subjects.
Methods: Subjects comprised of a general population sample (n=199) enriched with subjects with asthma (n=37) recruited from the European Respiratory Community Survey during 2011 and 2012, of which n=121 were healthy subjects. Repeated breath manoeuvres were performed and particles were counted and collected using the PExA® technique. ELISA kits were used for quantification of SP-A and albumin. Spearman rank correlations were used to test for linear relationships. Groups were compared using a nonparametric test.
Results: Healthy females and males exhaled similar number of particles in each exhalation, but females exhaled significantly more particles (p=0.005) when expressed as particles per litre exhaled air. There was a correlation (p<0.0001) between particles per exhalation and FEV1 (% pred). Number of exhaled particles increased with higher age. Regarding asthma, there was a correlation (p=0.02) between particles per exhalation and FEV1 (% pred). Increased bronchomotor tone was associated with decreased number of exhaled particles. There were no difference in SP-A and albumin concentrations between groups.
Conclusions: Number of exhaled particles seems to be associated with lung function, and could be a promising non-invasive biomarker.
- Copyright ©ERS 2015
