[Association between serum YKL-40 levels and endothelial function in hypertensive patients]

To explore the relationship between serum YKL-40 levels and endothelial function in patients with essential hypertension (EH).

Sixty EH patients [34 male, aged between 43 - 76 years, mean (59 ± 7) years] and 30 healthy subjects [17 male, mean age (57 ± 5) years] were enrolled in this study. Serum YKL-40 levels were measured by enzyme immunoassay (ELISA). Endothelial function [endothelin-1 (ET-1), nitric oxide (NO), flow-mediated dilatation (FMD)] was also measured. EH patients were further divided to no metabolic syndrome and metabolic syndrome group.

Serum uric acid, ET-1, hs-CRP were significantly higher while serum NO, FMD and NMD were significantly lower in EH group than in control group (all P < 0.05). YKL-40 was significantly higher in EH group than in the control group [51.7 (35.6 - 341.9) µg/L vs. 33.2 (23.3 - 167.3) µg/L, P < 0.05] and significantly higher in EH patients with metabolic syndrome than in EH patients without metabolic syndrome (152.3 µg/L vs. 94.2 µg/L, P < 0.05). In this cohort, serum YKL-40 level was positively correlated with SBP, DBP, BMI, TG and hsCRP(r = 0.360, 0.303, 0.281, 0.216, 0.530, all P < 0.05)but not correlated with FMD, ET-1 and NO (all P > 0.05).

Serum YKL-40 levels are increased compared to normal controls and positively correlated with blood pressure level but not with endothelial function parameters in hypertensive patients. Serum YKL-40 level might thus be used as a biomarker reflecting inflammation status other than endothelium function in hypertensive patients.