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Background: It is amply reported that patients with chronic obstructive pulmonary disease (COPD) have increased risk of cardiovascular disease (CVD). Recent evidence suggests that COPD patients have elevated concentrations of plasma homocysteine (Hcy), a transsulfuration pathway analyte that is commonly regarded as a CVD risk factor. Design: We comprehensively investigated the plasma concentrations of transsulfuration pathway analytes, and their relationship with markers of oxidative stress and inflammation, to identify which low molecular thiols might play a pathophysiological role both in CVD and in COPD. Hcy, cysteine (Cys), glutathione (GSH), cysteinylglycine (CysGly), glutamylcysteine (GluCys), taurine (Tau), oxidative stress markers (TBARS and protein‐SH, PSH) and the inflammation marker kynurenine/tryptophan (Kyn/Trp) ratio were measured in 54 COPD patients and 54 control subjects. Results: We found increased concentrations of total Hcy (P <.01) and total CysGly (P <.05) in COPD patients when compared to controls. Total Hcy and CysGly were also significantly associated with abnormal lung function parameters and COPD severity. In COPD patients, total Hcy was significantly associated with the Kyn/Trp ratio (P =.0017) whereas total CysGly was significantly associated with both PSH (P =.0298) and the Kyn/Trp ratio (P = <.0001). Conclusion: Both total Hcy and CysGly concentrations were significantly associated with the presence and severity of COPD and with markers of oxidative stress (total CysGly) and inflammation (total Hcy and CysGly). This suggests that specific low molecular mass thiols might play a role in the inflammatory and oxidative stress pathways involved in both CVD and COPD. [ABSTRACT FROM AUTHOR]

Chronic obstructive pulmonary disease ( COPD) and asthma are both characterized by heterogeneous chronic airway inflammation and obstruction as well as oxidative stress ( OS). However, it is unknown whether OS occurs in early disease and how to best assess its presence. Plasma OS markers ( TBARS, PSH, taurine, GSH, ergothioneine and paraoxonase 1 activity) and lung function tests were measured in patients with mild stable asthma ( n = 24) and mild stable COPD ( n = 29) and in age- and sex-matched controls. Forced expiratory volume in 1 s ( FEV1) was associated with age both in patients and control groups. By contrast, FEV1 was positively correlated with PSH only in COPD (ρ = 0·49, P = 0·007). In multiple logistic regression analysis, lower PSH was the only OS marker independently associated with increased odds of both asthma ( OR = 0·32, 95% CI 0·13-0·78, P = 0·01) and COPD ( OR = 0·50, 95% CI 0·26-0·95, P = 0·03). These findings suggest that proteins -SH are a sensitive OS marker in early COPD and asthma. [ABSTRACT FROM AUTHOR]