Serum H2S as an indicator of exacerbation and pulmonary arterial hypertension in chronic obstructive pulmonary disease

Abstract

Background and objective: Hydrogen sulfide (H2S) is a potential gasotransmitter produced by respiratory and vascular smooth muscle cells. Although some studies have examined H2S in chronic obstructive pulmonary disease (COPD), few have investigated its role in COPD exacerbations and pulmonary arterial hypertension (PAH). This study aimed to compare serum H2S levels between COPD patients and healthy controls, examine associations between H2S and COPD severity/exacerbations/PAH, and compare H2S levels between smokers and nonsmokers. Methods: Serum H2S was measured in 16 patients with stable COPD and 34 with acute exacerbations. COPD severity was classified using GOLD stages. Arterial blood gases, pulmonary arterial pressure by echocardiography, and clinical variables were assessed. Multivariable regression analyzed factors influencing H2S. ROC curves evaluated the diagnostic utility of H2S for exacerbations and PAH. Results: Serum H2S was lowest in GOLD stage IV patients compared to stages II and III. Levels were significantly lower in acute exacerbations versus stable COPD. COPD patients with PAH had lower H2S than those without. Arterial pH, FEV1, and FEV1/FVC positively associated with H2S, while PaCO2, severity, exacerbations, and PAH negatively influenced H2S. Optimal H2S cutoffs for indicating exacerbations and PAH were <46.7 μmol/L. Conclusions: Serum H2S may be a useful indicator of exacerbations and PAH in COPD patients.