title: Surfactant protein A and albumin in particles in exhaled air.
abstract: In this study we test the hypothesis that endogenous particles in exhaled air (PEx), non-invasively sampled from lower airways, are well suited for the analysis of respiratory tract lining fluid (RTLF) proteins, i.e., surfactant protein A (SP-A) and albumin. Ten healthy volunteers were included in the study and participated in two sampling sessions. Blood, exhaled breath condensate (EBC) and PEx were collected at each session. 100 L of breath were collected for each exhaled sample. Serum and exhaled samples were analyzed for SP-A using an in-house ELISA. Albumin was analyzed in exhaled samples using a commercial ELISA kit. SP-A detection rates were 100%, 21%, and 89% for PEx, EBC and serum, respectively. Albumin was detected in PEx, but not in EBC. SP-A measurements in PEx showed good repeatability with an intra-individual coefficient of variation of 13%. Both SP-A and albumin showed significant correlation to mass of PEx (r(s) = 0.93, p < 0.001 and r(s) = 0.86, p = 0.003, respectively). Sampling and analysis of PEx is a valid non-invasive method to monitor RTLF proteins sampled from the lower respiratory tract, as demonstrated here by example of SP-A and albumin analysis.
authors.affiliation: Occupational and Environmental Medicine, Sahlgrenska Academy, University of Gothenburg, Box 414, 405 30 Göteborg, Sweden.
authors.forename: Per
authors.initials: P
authors.lastname: Larsson
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Mirgorodskaya
authors.forename: Lena
authors.initials: L
authors.lastname: Samuelsson
authors.forename: Björn
authors.initials: B
authors.lastname: Bake
authors.forename: Ann-Charlotte
authors.initials: AC
authors.lastname: Almstrand
authors.forename: Anna
authors.initials: A
authors.lastname: Bredberg
authors.forename: Anna-Carin
authors.initials: AC
authors.lastname: Olin
mesh_terms: D000328:Adult; D000418:Albumins / Q000378:metabolism*; D001944:Breath Tests / Q000379:methods; D004797:Enzyme-Linked Immunosorbent Assay; D045853:Exhalation; D005260:Female; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism; D008173:Lung Diseases, Obstructive / Q000453:epidemiology / Q000378:metabolism* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D037662:Pulmonary Surfactant-Associated Protein A / Q000378:metabolism*; D011663:Pulmonary Surfactants / Q000378:metabolism*; D015203:Reproducibility of Results; D013048:Specimen Handling; D013548:Sweden / Q000453:epidemiology; D013997:Time Factors
chemical_list: D000418:Albumins; D018836:Inflammation Mediators; D037662:Pulmonary Surfactant-Associated Protein A; D011663:Pulmonary Surfactants