RT Journal Article SR Electronic T1 Hydrogen sulfide (H2S) in sputum and serum as a novel biomarker of COPD JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP P3984 VO 44 IS Suppl 58 A1 Junpei Saito A1 Alexander Mackay A1 Christos Rossios A1 David Gibeon A1 Patricia Macedo A1 Rudy Sinharay A1 Pankaj Bhavsar A1 Mitsuru Munakata A1 Jadwiga Wedzicha A1 Kian Fan Chung YR 2014 UL http://erj.ersjournals.com/content/44/Suppl_58/P3984.abstract AB Objectives: Hydrogen sulphide (H2S) is a gas produced by respiratory cells including smooth muscle cells and may play a role as a cellular gasotransmitter. The aim of the study is to evaluate whether H2S levels in serum or sputum could represent a new biomarker of COPD in a cross-sectional study.Methods: H2S levels in sputum and serum samples were measured using a sulphide sensitive electrode in 64 patients with stable COPD (S-COPD), 29 COPD subjects during acute exacerbation (AE-COPD), 14 healthy smokers, and 21 healthy non-smokers.Results: Sputum H2S levels in AE-COPD subjects were higher than those in S-COPD, healthy smoking and non-smoking subjects (p<0.001), but serum H2S levels in AE-COPD were lower than those in S-COPD (p<0.001). Thus, the sputum-to-serum ratio of H2S (H2S ratio) in AE-COPD subjects were higher than those in S-COPD, healthy smoking and non-smoking subjects (p<0.001). In 14 COPD subjects where concomitant sputum and serum H2S levels were measured at baseline and during an exacerbation, the mean ratio was increased during exacerbation (p<0.01). Both sputum and serum H2S levels correlated inversely with the degree of airflow obstruction measured as FEV1 %predicted and FEV1/FVC. Additionally, there were positive relationships between sputum neutrophils and H2S levels in sputum as well as serum (p<0.01). Finally, the optimal cut-off level of H2S ratio to predict an exacerbation was ≥0.44 (sensitivity of 93.1%, and specificity of 84.5%).Conclusion: The ratio of sputum-to-serum levels of H2S may provide a useful marker of COPD indicative of obstructive neutrophilic inflammation and of potential future risk of exacerbation.