[Placenta Growth Factor (PlGF) and Retinal Vascular Diseases--Current Knowledge from Experimental and Clinical...

Pathological angiogenesis is a major characteristic of many diseases, such as cancer and retinal vascular disorders. Vascular diseases of the eye, such as diabetic retinopathy (DR) and neo-vascular age-related macular degeneration (nAMD), are the main cause of severe vision loss. The specific role of the cytokine VEGF-A in these pathologies has been proven in many ways. Thus, VEGF-A is still the major target for antiangiogenic therapy. Recently, another angiogenic factor, the placental growth factor (PlGF), has become a focal point for clinical research. This interest is based on the fact that the expression of PlGF is limited to embryonic development and PlGF can hardly be found in healthy tissues. During pathological angiogenetic processes, such as retinal vascular diseases, however, PlGF is increasingly expressed. Substances which inhibit the effect of PlGF and thus pathological angiogenesis, without simultaneously affecting healthy tissues, could significantly extend the therapeutic options for the treatment of retinal vascular diseases. Convincing results have recently been published from clinical trials in oncology, as well as preclinical investigations in animal models of retinal vascular diseases. The aim of this review is to summarise the role of PlGF in retinal vascular diseases and the available experimental data on the therapeutic potential of PlGF inhibitors.