Abstract
Purpose :
Angiopoeitin-2 (Ang2) and vascular endothelial growth factor isoform A (VEGF-A) are multi-faceted cytokines involved in inflammation and epithelial mesenchymal transition (EMT), key steps in the pathogenesis of proliferative vitreoretinopathy (PVR). In particular, the relationship between Ang2 and PVR has not been previously reported. The aim of this study was to examine the relationship between severity of PVR and Ang2/VEGF in a rabbit model of PVR.
Methods :
PVR was surgically induced in 11 rabbit eyes by vitrectomy, retinotomy, cryotherapy and injection of platelet-rich plasma at baseline. Vitreous fluid samples were obtained at baseline and weeks 2, 3 and 4. The concentrations of VEGF-A and Ang2 were measured by enzyme-linked immunosorbent assay (ELISA). Severity of PVR was assessed on dilated fundal examination with indirect binocular ophthalmoscopy and graded based on the revised experimental PVR classification. Concentrations of VEGF-A and Ang2 at week 4 were compared to baseline and correlations between the cytokines with PVR severity were assessed.
Results :
Four weeks after PVR induction, 7 eyes (63.6%) developed stage 4 or worse PVR. The concentration of Ang2 at week 4 was significantly higher than baseline (15.9 x 103pg/ml vs 72.5 x 103pg/ml, p=0.0001). VEGF-A was elevated at week 4 compared to baseline (3.0 x 103pg/ml vs 11.1 x 103pg/ml) but the difference was not statistically significant (p =0.16). In addition, a significant positive correlation was observed between Ang2 and PVR severity (Spearman’s correlation coefficient 0.61, p=0.0002).
Conclusions :
Ang2 was significantly elevated in the vitreous of rabbit eyes with surgically induced PVR and correlated well with PVR severity. These results support the role of Ang2 in the pathogenesis of PVR.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.