Five vascular endothelial growth factor receptor (VEGFR) ligands (VEGF-A, -B, –C, -D, and placental growth factor [PlGF]) constitute the VEGF family. VEGF-A binds VEGF receptors 1 and 2 (VEGFR1/2), whereas VEGF-B and PlGF only bind VEGFR1. Although much research has been conducted on VEGFR2 to elucidate its key role in retinal diseases, recent efforts have shown the importance and involvement of VEGFR1 and its family of ligands in angiogenesis, vascular permeability, and microinflammatory cascades within the retina. Expression of VEGFR1 depends on the microenvironment, is differentially regulated under hypoxic and inflammatory conditions, and it has been detected in retinal and choroidal endothelial cells, pericytes, retinal and choroidal mononuclear phagocytes (including microglia), Müller cells, photoreceptor cells, and the retinal pigment epithelium. Whilst the VEGF-A decoy function of VEGFR1 is well established, consequences of its direct signaling are less clear. VEGFR1 activation can affect vascular permeability and induce macrophage and microglia production of proinflammatory and proangiogenic mediators. However the ability of the VEGFR1 ligands (VEGF-A, PlGF, and VEGF-B) to compete against each other for receptor binding and to heterodimerize complicates our understanding of the relative contribution of VEGFR1 signaling alone toward the pathologic processes seen in diabetic retinopathy, retinal vascular occlusions, retinopathy of prematurity, and age-related macular degeneration. Clinically, anti-VEGF drugs have proven transformational in these pathologies and their impact on modulation of VEGFR1 signaling is still an opportunity-rich field for further research.

五种血管内皮生长因子受体 (VEGFR) 配体（VEGF-A、-B、-C、-D 和胎盘生长因子 [PlGF]）构成了 VEGF 家族。VEGF-A 结合 VEGF 受体 1 和 2 (VEGFR1/2)，而 VEGF-B 和 PlGF 仅结合 VEGFR1。尽管对 VEGFR2 进行了大量研究以阐明其在视网膜疾病中的关键作用，但最近的研究表明 VEGFR1 及其配体家族在视网膜内血管生成、血管通透性和微炎症级联中的重要性和参与。VEGFR1 的表达取决于微环境，在缺氧和炎症条件下受到差异性调节，并且已在视网膜和脉络膜内皮细胞、周细胞、视网膜和脉络膜单核吞噬细胞（包括小胶质细胞）、Müller 细胞、感光细胞和视网膜中检测到 VEGFR1 的表达。色素上皮。虽然 VEGFR1 的 VEGF-A 诱饵功能已得到充分证实，但其直接信号传导的后果尚不清楚。VEGFR1 激活可以影响血管通透性并诱导巨噬细胞和小胶质细胞产生促炎和促血管生成介质。然而，VEGFR1 配体（VEGF-A、PlGF 和 VEGF-B）相互竞争受体结合和异二聚化的能力使我们对 VEGFR1 信号单独对糖尿病视网膜病变病理过程的相对贡献的理解变得复杂。视网膜血管闭塞、早产儿视网膜病变和年龄相关性黄斑变性。临床上，抗 VEGF 药物已被证明对这些病理学具有转化作用，并且它们对 VEGFR1 信号传导调节的影响仍然是一个充满机会的进一步研究领域。