Elevated YKL‐40 serum levels may contribute to wet age‐related macular degeneration via the ERK1/2 pathway

Abstract

Choroidal neovascularization (CNV) is a key characteristic of wet age‐related macular degeneration (AMD) that can lead to severe vision loss in the elderly. Anti‐VEGF therapy is currently the premier strategy for wet AMD, but it has limited efficacy. Previous studies have shown that chitinase‐3‐like‐1 (YKL‐40) can promote microangiogenesis and inflammation, but its effect on CNV formation has not yet been studied. Here, we investigated the potential role of YKL‐40 in wet AMD and the underlying mechanism(s). We report that the serum expression of YKL‐40 in wet AMD patients was significantly higher than that in control patients and was positively correlated with VEGF expression, indicating that YKL‐40 may participate in the development of wet AMD. In addition, YKL‐40 and VEGF expression levels were observed to be increased and the ERK1/2 pathway activated in the neuroretinal (NR) and RPE/choroid tissues of mice with laser‐induced CNV. The YKL‐40 and phosphorylated protein levels of the ERK1/2 pathway were decreased after intravitreal injection with an anti‐YKL‐40 antibody, suggesting that anti‐YKL‐40 could inhibit the activation of the ERK1/2 pathway. These results indicate that YKL‐40 may serve as a novel target for the diagnosis and treatment of wet AMD.

Keywords

• age‐related macular degeneration
• choroidal neovascularization
• YKL‐40
• vascular endothelial growth factor