ABSTRACT
<p><b>BACKGROUND</b>This study was to examine the expression of total vascular endothelial growth factor (VEGF) and the anti-angiogenic VEGF 165 b isoform in the vitreous body of retinopathy of prematurity (ROP) patients, and to further study the role of the VEGF splicing in the development of ROP.</p><p><b>METHODS</b>This was a prospective clinical laboratory investigation study. All patients enrolled received standard ophthalmic examination with stage 4 ROP that required vitrectomy to collect the vitreous samples. The control samples were from congenital cataract patients. The expression of total VEGF and the anti-angiogenic VEGF 165 b were measured by enzyme-linked immunosorbent assay. Results were analyzed statistically using nonparametric tests.</p><p><b>RESULTS</b>The total VEGF level was markedly elevated in ROP samples while VEGF 165 b was markedly decreased compared to control group. The relative protein expression level of VEGF 165 b isoform was significantly decreased in ROP patients which were correlated with the ischemia-induced neovascularization.</p><p><b>CONCLUSIONS</b>There was a switch of VEGF splicing from anti-angiogenic to pro-angiogenic family in ROP patients. A specific inhibitor that more selectively targets VEGF 165 and controls the VEGF splicing between pro- and anti-angiogenic families might be a more effective therapy for ROP.</p>
Subject(s)
Female , Humans , Infant, Newborn , Male , Enzyme-Linked Immunosorbent Assay , Infant, Premature , Prospective Studies , Protein Isoforms , Metabolism , Retinopathy of Prematurity , Metabolism , Vascular Endothelial Growth Factor A , Metabolism , Vitreous Body , MetabolismABSTRACT
<p><b>BACKGROUND</b>Retinopathy of prematurity (ROP) has become one of the leading causes of visual loss in children. Vascular endothelial growth factor A (VEGF-A) is the principal stimulator of angiogenesis. VEGF was differentially spliced from exon 8 to exons 8a and 8b to form two families: the pro-angiogenic VEGFxxx family and the anti-angiogenic VEGFxxxb family. Previous research has shown variable effeteness of bevacizumab in inhibiting retinal neovascularization in ROP. This study aimed to investigate whether the effectiveness of this inhibition depends on the relative ratio of the two VEGF isoforms.</p><p><b>METHODS</b>Intravitreal bevacizumab injection (IVB) was performed in the oxygen-induced-retinopathy (OIR) mice on postnatal day 12 (P12) (intravitreal phosphate buffered saline (PBS) injection as control). The Evans blue perfused retina were used to test the retinal neovascularization-leakage (NVL) area and non-perfusion (NP) area.</p><p><b>RESULTS</b>The retinal NVL and NP area in the IVB group were significantly smaller than the intravitreal PBS injection group (IVP group). On P17, the protein level of total VEGF isoforms was significantly inhibited compared to IVP group (P < 0.05) while VEGF(165)b isoform was slight reduced (P > 0.05). The switch from pro-angiogenic isoforms to anti-angiogenic isoforms after IVB could be found. The relative protein expression of VEGF(165)b isoform was significantly higher in IVB group than in IVP group (P < 0.05) on P17 which was correlated with the reduced ischemia-induced angiogenesis in OIR mice after IVB.</p><p><b>CONCLUSIONS</b>The anti-angiogenic effectiveness might depend on the relative high expression of VEGF(165)b after intravitreal bevacizumab injection. Anti-angiogenic therapy is a more effective therapy for ROP.</p>