Objective: To evaluate the effect of obesity on Lp-PLA2 in peripheral blood of adolescents and analyze the effect of Lp-PLA2 inhibition on the secretion of oxidized low density lipoprotein (oxLDL) by adipocytes in vitro. Methods: Peripheral blood was collected from 36 obese adolescents (obese group) and 36 healthy weight adolescents (control group), and the concentration of serum Lp-PLA2 was detected by chemiluminescence method. The adipocytes were cultured in vitro, and the culture supernatant was collected after stimulation with 67 pmol/L lipoprotein cholesterol (LDL-C) and 20 μmol/L Lp-PLA2 inhibitor for 48 and 72 hours. The concentration of Lp-PLA2 and oxLDL in the supernatant were detected by chemiluminescence and enzyme-linked immunosorbent assay (ELISA), respectively. The expression of Lp-PLA2 mRNA in adipocytes was measured by RT-PCR. Results: Compared with the control group\[（123.5±27.3）ng/mL], the level of Lp-PLA2 in peripheral blood of obese adolescents[（353.4±30.4）ng/mL]was significantly increased (t=33.76，P<0.05). The level of peripheral blood Lp-PLA2 in obese adolescents was positively correlated with body mass index (r=0.414, P=0.012) and waist circumference (r=0.460, P=0.004). Univariate regression analysis showed that total cholesterol, LDL-C, apolipoprotein A1 and apolipoprotein B were associated with elevated Lp-PLA2. Compared to the control group, the concentration of Lp-PLA2 and the level of Lp-PLA2 mRNA in adipocytes were significantly increased after stimulation with LDL-C for 48 hours（P<0.01）. Furthermore, the production of oxLDL by adipocytes was significantly decreased after treating with Lp-PLA2 inhibitors（P<0.01）.Conclusion: Lp-PLA2 may be an important factor in the increase of cardiovascular risk in adulthood of obese adolescents.

［Key words］adolescen; Lp-PLA2; cardiovascular risk; obesity