Article Text
Abstract
Introduction Anti-vascular endothelial growth factor (VEGF) agents are used worldwide for advanced-stage diabetic retinopathy (DR). In contrast, apart from blood glucose control, there are no specific treatments that can limit the progression of early-stage DR that starts with pericyte loss and the destruction of the blood–retinal barrier. Here, we examined the efficacy of aflibercept, a potent anti-VEGF agent, against early-DR pathologies in a murine model of streptozotocin (STZ)-induced DR.
Research design and methods STZ was intraperitoneally administered in 8-week-old C57BL/6N male mice. After 4 weeks, the mice were divided into aflibercept-treated and saline-treated groups. Eight weeks after the STZ injection, vascular permeability/leakage was measured with fluorescein angiography in live mice. At 4, 6, and 8 weeks after the STZ injection, the eyes were enucleated, flat-mounted, and stained for platelet-derived growth factor receptor-β to assess pericyte abundance, CD45 to assess leukocyte recruitment, and fluorescein isothiocyanate dextran to assess perfusion. VEGF levels were quantified in each group. The effects of aflibercept on pericyte number, perfusion status, and leukocyte recruitment/accumulation on mice with diabetes retina were evaluated.
Results Our murine model successfully replicated the salient pathologies of DR such as pericytes loss, hyperpermeability, and perfusion blockage. Interestingly, numerous leukocytes and leukocyte clumps were found in diabetic retinal capillaries, especially in the non-perfused border area of the retina, suggesting a possible mechanism for non-perfusion and related pericyte damage. Treatment with aflibercept in mice with diabetes inhibited the upregulation of VEGF and the associated adhesion molecules while reducing the defects in perfusion. Aflibercept also attenuated pericyte loss in the diabetic retina.
Conclusion VEGF inhibition through aflibercept treatment decreased leukocyte recruitment and aggregation, perfusion blockage, retinal hypoperfusion, and hyperpermeability in mice with diabetes and ultimately attenuated pericyte loss. Our findings suggest that anti-VEGF strategies may prove useful as possible therapies for limiting the progression of early-stage DR.
- retinopathy
- pericyte
- leukocytes
- streptozotocin
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Footnotes
EJS and JAC contributed equally.
J-YK and YHY contributed equally.
Presented at Part of this study was presented as a poster at the Annual Meeting of the Association for Research in Vision and Ophthalmology, Vancouver, British Columbia, Canada, April 28–May 2, 2019.
Contributors EJS and JAC performed experiments and wrote the manuscript. YHY and J-YK coordinated the study, reviewed the manuscript and are the guarantors of this work; in this capacity, they had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.
Funding This study was supported by grants from Bayer Healthcare (IIR-KR-2017–4533) and the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (2017R1D1A1B05028221) and the Brain Research Program of the NRF funded by the Korean government (NRF-2017M3C7A1028949).
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval The experimental protocols were approved (approval ID: IACUC 2018-13-020) by the Institutional Animal Care and Use Committee of Asan Institute for Life Sciences, Asan Medical Center, University of Ulsan College of Medicine (Seoul, Korea).
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement All data relevant to the study are included in the article or uploaded as supplemental information.
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