Plasma Lipid Profiling Identifies Phosphatidylcholine 34:3 and Triglyceride 52:3 As Potential Markers Associated with Disease Severity and Oxidative Status in Chronic Obstructive Pulmonary Disease

To identify plasma alterations in lipid species in patients with chronic obstructive pulmonary disease (COPD), as well as, relationships with smoking status, oxidative and inflammatory markers. Plasma was obtained from 100 patients with COPD and 120 healthy controls. Pulmonary function was assessed by plethysmography. Serum levels of IL-6 and TNF-α were determined by ELISA. Oxidative stress parameters were measured using standard methods. Lipids were extracted then analyzed by Matrix-Assisted Laser Desorption and Ionization Time-Of-Flight Mass Spectrometry (MALDI-TOF-TOF-MS). More than 40 lipid compounds were identified within plasma samples. Among these 19 lipid species including plasmalogens (PC O-), phosphatidylcholines (PC), and triglycerides (TG) were significantly altered in COPD. A decreased expression of PC O- (36:1, 36:2, 36:3, 36:4, 38:4, 38:5) species was found in patients with different severities compared to healthy controls. There was also a decrease in PC (34:3, 36:0, 36:4, 36:5, 40:6, 40:7) species in COPD patients. PC (34:3) levels were positively correlated with disease progression and pulmonary function decline (forced expiratory volume in 1 s (FEV1)) (r = 0.84, p < 0.001) and inversely correlated with thiobarbituric acid-reactive substances (TBARS) (r = − 0.77, p < 0.001). TG (50:0, 50:1, 52:1, 52:2, 52:3, 52:4, 54:4) species were altered in COPD patients and in those with advanced disease stages. Significant correlations between FEV1, TBARS, peroxynitrite, and TG (52:3) were found among COPD patients (r = − 0.69; r = 0.86; r = 0.77, p < 0.001, respectively). PC (34:3) and TG (52:3) could be potential lipid signatures of COPD that correlate with altered pulmonary function and oxidative status.