Intermittent hypoxia in obstructive sleep apnoea (OSA) is related to inflammation and metabolic abnormalities. Soluble low-density lipoprotein receptor-related protein-1 (sLRP-1) is involved in anti-inflammatory and metabolic processes. However, its ligand, calreticulin (CALR) promotes pro-inflammatory responses and apoptosis. Our aim was to analyse the levels of these biomarkers in OSA. We recruited 46 patients with OSA and 30 control subjects. Inpatient sleep study was performed and fasting plasma samples were collected. Triglyceride glucose index (TyG) and atherogenic index of plasma (AIP) were calculated. Plasma sLRP-1 levels were significantly lower in the OSA group compared to the controls (1.67 (0.90-2.11) mg/L vs. 1.99 (1.53-3.51) mg/L; p = 0.04) after adjustment for age, gender, BMI and lipid profile. Plasma sLRP-1 concentrations were inversely related to age (r = -0.29), BMI (r = -0.35), cigarette pack years (r = -0.31), LDL-C (r = -0.34) and triglyceride levels (r = -0.27), TyG (r = -0.37) and AIP (r = -0.27) as well as to the oxygen desaturation index (ODI, r = -0.24; all p < 0.05). BMI (p = 0.01) and ODI (p = 0.04) were independent predictors for low sLRP-1 levels. CALR did not differ significantly between the two groups (0.23 (0.17-0.34) ng/mL vs. 0.24 (0.20-0.36) ng/mL p = 0.76). We detected lower sLRP-1 levels in subjects with OSA which could contribute to metabolic abnormalities associated with this disease.
Keywords: OSA; inflammation; intermittent hypoxia; sleep apnoea.