Lipoprotein-associated phospholipase A2 levels as a predictor of cardiovascular risks in patients with COPD and obstructive sleep apnea

Abstract

Background: Lipoprotein-associated phospholipase A2 (Lp-PLA2) is an inflammatory mediator used as a novel marker for vascular specific inflammation, atherosclerosis and cardiovascular risks in humans. Both chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) are associated with frequent cortical arousals on polysomnography, and increased activation of inflammatory cells and molecular mechanisms associated with atherosclerosis and cardiovascular complications. Objective: To study the relation between Lp-PLA2 level as a marker of cardiovascular risks and arousal index in patients with OSA, COPD and overlap syndrome (COPD + OSA). Patients and methods: Sixty participants were recruited, divided into four groups (15 in each group) based on their polysomnographic and spirometric data; group I (normal), group II (OSA), group III (COPD) and group IV (overlap syndrome). Fasting serum samples were used to estimate lipid profile and Lp-PLA2 concentrations. Results: The apnea–hypopnea, arousal, desaturation indices, lipid profile and Lp-PLA2 levels were significantly increased in all patient groups compared to control. The arousal index and Lp-PLA2 level were significantly increased in overlap syndrome more than OSA and COPD patients. Lp-PLA2 level was independent predictor of arousal index in all patient groups. Conclusions: Patients with overlap syndrome have a higher arousal index and Lp-PLA2 level hence more cardiovascular risks than either OSA or COPD alone. The Lp-PLA2 level may be used as an independent predictor of cardiovascular risks in patients with OSA, COPD and overlap syndrome.

Keywords

• Cardiovascular disease
• COPD
• Inflammation
• Respiratory neurobiology and sleep
• Sleep apnea