Decreased galectin-1 levels in obstructive sleep apnea: a novel biomarker

Objective: Obstructive sleep apnea (OSA) is a common disease, which may cause oxidative stress because of intermittent apnea/hypopnea attacks occurring during sleep. In this study, we aimed to investigate the relation between oxidative stress and OSA by examining the serum levels of paraoxonase-1 (PON1), arylesterase (ARES), and oxidized low-density lipoprotein (LDL) as well as galectin-1 (gal-1) in patients with OSA. Methods: A consecutive 100 patients undergoing polysomnography (PSG) between 2018 and 2019 in our sleep laboratory were enrolled in the study. Their demographic data and body mass index were recorded. On the morning after PSG, peripheral venous blood samples were collected from the fasting subjects. The patients were divided into OSA (apnea-hypopnea index [AHI] >= 5) and non-OSA groups (AHI < 5) according to their AHI scores. The serum levels of PON1, ARES, oxidized LDL, and gal-1 were compared between the groups. Results: There were 67 (67%) men and 33 (33%) women with the mean age of 47.2 +/- 11.8 years and a mean BMI of 29.8 +/- 3.9. The mean AHI and oxygen desaturation indices were found to be 19.7 +/- 20.7 and 19.2 +/- 24.8, respectively. No significant difference was revealed in serum PON1, ARES, and oxidized LDL levels between the OSA and non-OSA groups (PON1 p = 0.678, ARES p = 0.589, and oxidized LDL p = 0.512). Gal-1 levels were observed to be significantly downregulated in patients with OSA (p = 0.014). Conclusion: No statistically significant difference was found in the serum levels of PON1, ARES, and oxidized-LDL in patients with OSA. Only gal-1 levels were found to be significantly decreased in these patients. Therefore, serum gal-1 levels can be considered a novel biomarker for OSA after further studies confirming its correlation with OSA.