APLN and retinopathy of prematurity: Plasma apelin-13 levels were significantly lower in the ROP group (91.8 ± 26.9 pg/mL) than in the control group (126.0 ± 27.0 pg/mL), while plasma VEGF levels were significantly higher in the ROP group (113.1 ± 27.3 pg/mL) than in the control group (81.8 ± 20.9 pg/mL) (both P < 0.001; Table 2; Fig. 2).