YKL-40: may be use as a new inflammatory biomarker in obstructive sleep apnea syndrome?

YKL-40 [chitinase-3 like-1 (CHI3L1)] is a glycoprotein, has been implicated in inflammation, endothelial dysfunction, tissue remodelling and it is accepted as a noninvasive prognostic biomarker for inflammation. In this study, we aimed to underline usability of serum YKL-40 as an inflammatory biomarker in patients with obstructive sleep apnea syndrome (OSAS).

Two groups OSAS patients [Group I: Mild-moderate OSAS, n:43; median apnea-hypopnea index: AHI, /hour:18], Group II: Severe OSAS, n: 25; AHI:41.6] and healthy control group [n:25, AHI: 3.6] were included in the study. Serum YKL-40 level was tested in serum samples taken after polysomnography in OSAS patients and control group. In addition, the association of serum YKL-40 level with age, body mass index and polysomnografic parameters were analyzed in the OSAS patient groups.

Median serum YKL-40 level was 20.30 ng/mL (range 8.01-73 ng/mL) in mild-moderate OSAS patients, and 22.58 ng/mL (9.17-99 ng/mL in severe OSAS patients, 18 ng/mL (range 7.36-88 ng/mL) in control group (p< 0.05). Serum YKL-40 level was found to be correlated with AHI in patient with mild-moderate OSAS patients (p< 0.05) and serum YKL-40 level was found to be correlated with age, total hypopnea time (minutes) in severe OSAS patients (p< 0.05). There was no relationship serum YKL-40 level with other studied variables (p> 0.05).

At the end of this study, we found that serum YKL-40 level increase with severity of OSAS. The findings suggest that YKL-40 may be a useful biomarker for inflammation in patients with OSAS.