Higher Aqueous Level of Lipocalin-2 in Macular Fibrosis Secondary to Neovascular Age-related Macular Degeneration

Abstract

Purpose : Previously, we reported higher plasma levels of lipocalin-2 in neovascular age-related macular degeneration (nAMD) patients with macular fibrosis. This study further investigated the aqueous level of lipocalin-2 in nAMD with and without macular fibrosis and the link between intraocular levels of lipocalin-2 and clinical presentations, including the short-term response to anti-VEGF therapy.

Methods : Forty-eight nAMD patients (24 with choroidal neovascularisation (CNV), 24 with polypoidal choroidal vasculopathy (PCV)), and 24 age-matched cataract patients (as controls) were recruited to this study. Half of the CNV and PCV patients had macular fibrosis and the other half did not. Retinal lesions were examined by fundus colour photography and optical coherence tomographic angiography. Aqueous humor was collected during intravitreal anti-VEGF injection (for nAMD patients) or cataract surgery (for controls). The aqueous level of lipocalin-2 was measured using the Luminex multiplex assay.

Results : The aqueous level of lipocalin-2 was marginally higher in nAMD patients compared to controls. The aqueous level of lipocalin-2 was significantly higher in nAMD patients with macular fibrosis but not in those without compared to that in the controls. The level of lipocalin-2 correlated positively with the central retinal thickness (CRT, r = 0.441, P = 0.002). The level of lipocalin-2 correlated negatively with the outer retinal vascular area (r = -0.585, P = 0.017) of the macula. No correlation was observed between the intraocular levels of lipocalin-2 and the improvement of visual acuity or the changes in CRT. No correlation was observed between the levels of lipocalin-2 and the number of intravitreal anti-VEGF injections.

Conclusions : nAMD patients with macular fibrosis had a higher aqueous level of lipocalin-2. Considering that nAMD patients also had significantly higher plasma levels of lipocalin-2, our results suggest that lipocalin-2 may play a critical role in the pathogenesis of macular fibrosis.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.

 

Expression levels of lipocalin-2 in the aqueous humor in CNV and PCV subgroups with or without macular fibrosis.

 

Correlations between the aqueous levels of lipocalin-2 and clinical parameters in nAMD Patients.