title: Intraocular and systemic levels of vascular endothelial growth factor in advanced cases of retinopathy of prematurity.
abstract: OBJECTIVE
  To measure vitreous, aqueous, subretinal fluid and plasma levels of vascular endothelial growth factor in late stages of retinopathy of prematurity.
  
  
  METHODS
  Interventional study. We enrolled patients with clinical diagnoses of bilateral stage V retinopathy of prematurity, confirmed by b-scan ultrasound and programmed for vitrectomy. During surgery we took samples from blood, aqueous, vitreous, and subretinal fluids. The vascular endothelial growth factor concentration in each sample was measured by ELISA reaction. A control sample of aqueous, vitreous and blood was taken from patients with congenital cataract programmed for phacoemulsification. For statistical analysis, a Mann-Whitney and a Wilcoxon W test was done with a significant P value of 0.05.
  
  
  RESULTS
  We took samples of 16 consecutive patients who met the inclusion criteria. The vascular endothelial growth factor levels in the study group were: aqueous, 76.81 ± 61.89 pg/mL; vitreous, 118.53 ± 65.87 pg/mL; subretinal fluid, 1636.58 ± 356.47 pg/mL; and plasma, 74.64 ± 43.94 pg/mL. There was a statistical difference between the study and the control group (P < 0.001) in the aqueous and vitreous samples.
  
  
  CONCLUSIONS
  Stage 5 retinopathy of prematurity has elevated intraocular levels of vascular endothelial growth factor, which remains high despite severe retinal lesion. There was no statistical difference in plasma levels of the molecule between the control and study group.
authors.affiliation: Retina Department Asociación para Evitar la Ceguera en México IAP, México City, México. rvelezmx@yahoo.com
authors.forename: Raul
authors.initials: R
authors.lastname: Velez-Montoya
authors.forename: Carmen
authors.initials: C
authors.lastname: Clapp
authors.forename: Jose Carlos
authors.initials: JC
authors.lastname: Rivera
authors.forename: Gerardo
authors.initials: G
authors.lastname: Garcia-Aguirre
authors.forename: Virgilio
authors.initials: V
authors.lastname: Morales-Cantón
authors.forename: Jans
authors.initials: J
authors.lastname: Fromow-Guerra
authors.forename: Jose Luis
authors.initials: JL
authors.lastname: Guerrero-Naranjo
authors.forename: Hugo
authors.initials: H
authors.lastname: Quiroz-Mercado