Purpose: To understand better the role of vascular endothelial growth factor (VEGF) and stromal cell-derived factor 1alpha (SDF-1alpha) in the pathogenesis of retinopathy of prematurity (ROP).
Design: Experimental study.
Participants: The study group consisted of 22 eyes with stage 4 ROP (12 vascularly active, 10 vascularly inactive), from which vitreous samples were obtained. Vitreous samples from 5 eyes undergoing surgery for congenital cataract were used as controls.
Methods: The vitreous samples were analyzed for concentrations of total protein, VEGF, and SDF-1alpha. Vascular activity was graded at the time of surgery and was defined as the presence of plus disease, neovascularization growing onto the vitreous at the ridge or tractional detachment area, or combined effusive and tractional retinal detachment.
Main outcome measures: Vitreous concentrations of VEGF and SDF-1alpha were compared among vascularly active stage 4 ROP eyes, vascularly inactive stage 4 ROP eyes, and control eyes.
Results: Vitreous concentrations of VEGF and SDF-1alpha were elevated in eyes with ROP compared with control eyes. The median VEGF level was 59 pg/ml (range, 38-135 pg/ml) in the control group, 316 pg/ml (range, 105-665 pg/ml) in the vascularly inactive ROP group, and 3454 pg/ml (range, 774-8882 pg/ml) in the vascularly active ROP group. The median SDF-1alpha level was 327 pg/ml (range, 299-393 pg/ml) in the control group, 609 pg/ml (range, 515-1116 pg/ml) in the vascularly inactive ROP group, and 1029 pg/ml (range, 807-3015 pg/ml) in the vascularly active ROP group. The differences in both vitreous VEGF and SDF-1alpha concentrations between the three groups were statistically significant (P<0.001 and P<0.001, respectively). The eyes graded as vascularly active at the time of surgery demonstrated the highest vitreous levels of both VEGF and SDF-1alpha, and these levels were statistically significant when compared with vascularly inactive eyes (P<0.001 and P = 0.001, respectively) and control eyes (P = 0.001 and P = 0.001, respectively).
Conclusions: These findings confirm the increase in vitreous VEGF and SDF-1alpha levels in eyes with vascularly active stage 4 ROP. Anti-VEGF treatment may be of benefit in some eyes that develop ROP.