VEGF in Tears as a Biomarker for Exudative Age-Related Macular Degeneration: Molecular Dynamics in a Mouse Model and Human Samples

Vascular endothelial growth factor (VEGF) is a key mediator of exudative age-related macular degeneration (eAMD), yet non-invasive biomarkers for disease monitoring remain limited. This study evaluates VEGF levels in human tear fluid as a potential biomarker for eAMD and investigates the molecular dynamics of VEGF in a laser-induced choroidal neovascularization (lCNV) mouse model. Tear VEGF levels were quantified using proximity qPCR immunoassays in eAMD patients (n = 29) and healthy controls (n = 21) and correlated with optical coherence tomography (OCT) findings. Molecular analyses, including immunohistochemistry, gene expression profiling, and phosphorylation assays, were conducted on choroid-retinal pigment epithelium (RPE) and lacrimal gland (LG) tissues from lCNV mice (n = 25). Tear VEGF levels were significantly elevated in eAMD patients, correlating with disease severity. Females exhibited higher VEGF levels, a pattern not replicated in the mouse model. In lCNV mice, VEGF overexpression originated from the choroid-RPE, driven by hypoxic and inflammatory signaling, with no significant LG contribution. Increased VEGF, IL-6, and vimentin expression, along with NF-κB and STAT3 activation, were observed. These findings suggest that tear VEGF is a promising non-invasive biomarker for eAMD, warranting further validation for clinical application in disease monitoring and treatment optimization.