Long-acting FGF21 inhibits retinal vascular leakage in vivo and in vitro model

Abstract

Purpose : Macular edema secondary to retinal vascular leakage is a common complication in diabetic retinopathy (DR). Anti-VEGF therapy is widely used but only partially effective at reducing edema. An alternative treatment is strongly desired. Fibroblast growth factor 21 (FGF21) is a major metabolic regulator, which improves retinal neuronal function and inhibits retinal neovascularization in diabetic mice modeling. The impact of FGF21 on retinal vascular leakage is unknown. We aim to explore this area.

Methods : Six-eight week-old male C57BL/6J mice were pre-treated with long-acting FGF21 analog PF-05231023 (10mg/kg) or vehicle (PBS) intraperitoneally (IP) twice a week for 1 week. One week later, retinal vascular leakage was induced with intravitreal administration of mouse VEGF164 (100ng/ul). The control group was injected IP with PBS twice a week and control PBS intravitreally. Five hours after VEGF injection, we injected FITC-dextran (70kDa, 100mg/ml) retro-orbitally to examine retinal vascular leakage. The fluorescence intensities of FITC-dextran of the leakage in the images were analyzed using the Image Analysis Module (Zen, Zeiss). In PF-05231023 or PBS-treated primary human retinal microvascular endothelial cells (HRMECs) in vitro, cell permeability was induced with human VEGF165 (10ng/ml) treatment. Transepithelial electrical resistance (TEER) was measured with the electrical resistance system. Cell permeability was examined using FITC-dextran (70kDa, 0.5mg/ml) and Texas Red (4kDa, 0.1mg/ml). ANOVA with Bonferroni’s multiple comparison test was used for comparison of results as specified (Prism v6.0, GraphPad).

Results : In the mouse model of retinal vascular leakage in vivo, we could subtract vessel fluorescence intensities from the whole retina with using the Intellesis Trainable Segmentation (Zen, Zeiss). The intensity of vascular leakage was significantly reduced in PF-05231023 versus PBS-treated group (PF-05231023: 0.92 ± 0.10; PBS: 1.80 ± 0.33; P=0.03, n=15). In VEGF-induced HRMECs in vitro, PF-05231023 (100ng/ml) versus PBS significantly preserved TEER (P<0.01). PF-05231023 (50ng/ml, 100ng/ml) versus PBS also prevented cell permeability identified with FITC-dextran and Texas Red (P<0.01, respectively).

Conclusions : Long-acting FGF21 may have therapeutic potential to prevent or treat macular edema in DR.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.