Effect of aflibercept on proliferative vitreoretinopathy: Proteomic analysis in an experimental animal model

The aim of this study was to monitor inflammatory, proliferative and progressive effects of proliferative vitreoretinopathy (PVR) and aflibercept treatment in dispase induced PVR rat model by proteomic analysis.

A total of 35 male Long Evans pigmented rats were divided into three groups, namely, PVR (dispase+saline), PVR+aflibercept (dispase+aflibercept) and control. The PVR group received 2 μl of 0.03 IU/μl dispase and 2 μl saline, the PVR+aflibercept group received 2 μl of 0.03 IU/μl and 2 μl of 40 mg/ml aflibercept at the first day of the experiment. At the end of the 6th week all retina and vitreous specimens were collected by evisceration and transferred to the proteomics laboratory for analysis. Proteomic analysis by 2D gel electrophoresis coupled with MALDI-TOF/TOF was performed.

In the PVR and PVR+aflibercept group 16 different proteins that were identified to be differentially regulated in comparison to the control group. In the PVR+aflibercept group, ENO1, ENO2, LDH-B, PEBP-1 and GS levels were higher than the PVR group. In addition, the association of proteins such as UCHL, PEBP1, PDHB and ENO1 with PVR has been demonstrated for the first time.

STRING analysis elucidated the functional protein-protein interaction among the differentially regulated proteins and highlighted that those proteins mainly played roles in carbon and nucleotide metabolisms. Functional analysis of the differentially regulated proteins indicated the presence of inflammation, gliosis and retinal damage in the PVR group. Aflibercept treatment had pronounced effect on prevention of inflammation and retinal damage while causing a slight increase in gliosis. However, aflibercept treatment was not effective enough to normalize the levels of differentially regulated proteins of the PVR group. Therefore, we predict that the treatment dose of aflibercept used in this study was below of its ideal concentration and should be increased in the future studies. The differential regulation of these structural proteins in this study should shed some light to the mechanism of glial wound formation in the retina and guide future treatment modalities.