Utility of urinary Clara cell protein (CC16) to demonstrate increased lung epithelial permeability in non-smokers exposed to outdoor secondhand smoke

• Published in: Journal of exposure science & environmental epidemiology Vol. 23; no. 2; pp. 183 - 189
• Main Authors: St Helen, Gideon, Holland, Nina T, Balmes, John R, Hall, Daniel B, Bernert, J Thomas, Vena, John E, Wang, Jia-Sheng, Naeher, Luke P
• Format: Journal Article
• Language: English
• Published: New York Nature Publishing Group US 01.03.2013; Nature Publishing Group
• Subjects: 692/53; 704/172/169/895; Bioindicators; Biological markers; Biomarkers; Biomarkers - metabolism; Cell Membrane Permeability; Cells; Cigarettes; Contamination; Cross-Over Studies; Environmental Exposure; Epidemiology; Epithelial Cells - metabolism; Exposure; Females; Health aspects; Humans; Lung - cytology; Lung - metabolism; Lungs; Males; Medicine; Medicine & Public Health; Nonsmokers; original-article; Passive smoking; Permeability; Properties; Proteins; Statistical methods; Tobacco smoke; Tobacco Smoke Pollution; Uteroglobin - metabolism; CC16; epithelial permeability; smoking bans; secondhand smoke; tobacco control; biomarkers
• ISSN: 1559-0631; 1559-064X; 1559-064X
• DOI: 10.1038/jes.2012.68

The objective of this study was to assess the utility of urinary Clara cell protein (CC16) as a biomarker of increased lung epithelial permeability in non-smokers exposed to outdoor secondhand smoke. Twenty-eight healthy non-smoking adults visited outdoor patios of a restaurant and a bar where non-participants smoked and an open-air control with no smokers on three weekend days in a crossover study; subjects visited each site once for 3 h. Urine samples were collected at baseline, immediately post exposure and next morning, and analyzed for CC16. Changes in CC16 across location types or with cigarette count were analyzed using mixed-effect models, which included all subjects and stratified by gender. Urinary CC16 was higher in males ( n =9) compared with females ( n =18) at all measurement occasions ( P <0.002), possibly reflecting prostatic contamination. Urinary CC16 from pre-exposure to post-exposure was higher following visits to restaurant and bar sites compared with the control among females but this increase did not reach statistical significance. Post-exposure to pre-exposure urinary CC16 ratios among females increased with cigarette count ( P =0.048). Exposure-related increases in urinary CC16 were not seen among males. In conclusion, urinary CC16 may be a useful biomarker of increased lung epithelial permeability among female non-smokers; further work will be required to evaluate its applicability to males.