The role of PSGL-1 and P-selectin in OSA

Background: Obstructive sleep apnoea (OSA) is characterised by chronic intermittent hypoxia (CIH), which can induce expression of adhesion molecules, such as P-selectin. P-selectin interacts with its major ligand, the P-selectin glycoprotein ligand-1 (PSGL-1). PSGL-1 expressed on leukocytes and its interaction with P-selectin plays important role in rolling and migration of leukocytes trough the endothelium. The aim of this study to evaluate circulating P-selectin and PSGL-1 concentrations and to understand their role in the pathogenesis of OSA. Methods: 51 patients with OSA and 42 healthy volunteers were recruited. Blood samples were taken before and after a diagnostic polysomnography (PSG). The concentration of plasma PSGL-1 and P-selectin was measured using ELISA. Results: There was no difference between circulating PSGL-1 levels of OSA patients and control subjects, either in the evening or in the morning (478.06 ± 170.43 U/ml vs. 497.95 ± 236.09 U/ml p = 0.67 in the morning and 476.20 ± 217.24 U/ml vs. 495.72 ± 230.81 U/ml p = 0.70 in the evening). P-selectin levels were significantly higher in OSA patients compared to the control group (18.43 ± 7.40 vs. 22.85 ± 11.90 ng/ml in controls and OSAS respectively, p = 0.03). There was no correlation between OSA severity and circulating PSGL-1, but P-selectin correlated significantly with AHI (r = 0.45, p Conclusion: Our results suggest that endothelial activation plays a role in OSA without altering adhesion molecules on leukocytes.