For patients with proliferative diabetic retinopathy (PDR) who do not respond adequately to pan-retinal laser photocoagulation (PRP) or anti–vascular endothelial growth factor (VEGF) therapies, we hypothesized that vascular cells within neovascular tissue secrete autocrine/paracrine angiogenic factors that promote disease progression. To identify these factors, we performed multiplex ELISA angiogenesis arrays on aqueous fluid from PDR patients who responded inadequately to anti-VEGF therapy and/or PRP and identified plasminogen activator inhibitor-1 (PAI-1). PAI-1 expression was increased in vitreous biopsies and neovascular tissue from PDR eyes, limited to retinal vascular cells, regulated by the transcription factor hypoxia-inducible factor (HIF)-2α, and necessary and sufficient to stimulate angiogenesis. Using a pharmacologic inhibitor of HIF-2α (PT-2385) or nanoparticle-mediated RNA interference targeting
Pai1
, we demonstrate that the HIF-2α/PAI-1 axis is necessary for the development of retinal neovascularization in mice. These results suggest that targeting HIF-2α/PAI-1 will be an effective adjunct therapy for the treatment of PDR patients.
Statistical analysis was performed with Microsoft Excel, version 16.0.16327.20248, or Prism, version 8.0, software (GraphPad). Statistical differences between 2 or multiple heterogenous groups were determined by unpaired Student's t test or 1-way or 2-way ANOVA. Analysis of data was performed using Excel.Study approval. All animal experiments were performed in accordance with the Animal Care and Use Program at Johns Hopkins University and were approved by the Institutional Animal Care and Use Committee (IACUC). All studies involving patients or patient tissue were approved by the Institutional Review Board of Johns Hopkins University School of Medicine. All participants provided written informed consent prior to enrolment in the study.
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