Which factor is a significant inhibitor of angiogenesis?

Pigment epithelium-derived factor (PEDF) plays a crucial role as a significant inhibitor of angiogenesis. It is a neurotrophic factor that is primarily produced by retinal pigment epithelial cells and has been shown to possess strong anti-angiogenic properties. PEDF acts by counteracting the effects of pro-angiogenic factors such as vascular endothelial growth factor (VEGF), thereby helping to regulate and maintain normal blood vessel formation.

In contexts where inappropriate angiogenesis contributes to conditions like age-related macular degeneration (AMD), the presence of PEDF can help prevent the abnormal growth of blood vessels which is often associated with the progression of these diseases. This makes PEDF a vital component in ocular health and a potential therapeutic target for diseases driven by neovascularization.

The other factors mentioned, such as VEGF, angiopoietin-1, and TGF-α, are known for promoting angiogenesis in various physiological and pathological processes, highlighting the distinct role of PEDF as an inhibitor in this context.