Aqueous humour concentrations of HB-EGF, EGF and VEGF-A and axial length in humans.

Abstract

Purpose: To investigate relationships between the intraocular concentrations of heparin-binding epidermal growth factor (HB-EGF), epidermal growth factor (EGF) and vascular endothelial growth factor A (VEGF-A) in dependence on axial length in humans.

Design: Clinical interventional cohort study.

Participants: Patients with cataract who underwent routine cataract surgery. Inclusion criterion was the absence of any retinal or optic nerve disease except for myopic macular degeneration (MMD) without myopic choroidal neovascularization.

Methods: Using a Luminex system, we measured the concentrations of HB-EGF, EGF and VEGF-A in aqueous humour samples taken from patients during cataract surgery.

Main outcome measures: Intracameral concentration of EGF, HB-EGF and VEGF; Axial length.

Results: The study included 68 patients (age: 61.1 ± 11 years; range: 44-85 years) with a mean axial length of 27.11 ± 3.11 mm (range: 22.09-35.64 mm). The HB-EGF concentration (mean: 3.17 ± 0.99 pg/mL) increased with longer axial length (β = 0.43; p < 0.001) and was not associated with age (p = 0.10) and intracameral EGF concentration (p = 0.22). The EGF concentration (mean: 0.22 ± 0.12 pg/mL) increased with longer axial length (β = 0.35; p = 0.004) and higher prevalence of advanced MMD (β = 0.35; p = 0.008) and was not associated with age (p = 0.28) and intracameral VEGF-A concentration (p = 0.09). The VEGF-A concentration (mean: 118 ± 150 pg/mL) decreased with longer axial length (β = -0.54; p < 0.001), higher intracameral concentration of HB-EGF (β = -0.26; p = 0.03) and lower MMD prevalence (β = -0.31; p = 0.02) and was not associated with age (p = 0.47) and intracameral EGF concentration (p = 0.09).

Conclusions: With the concentrations of HB-EGF and EGF increasing with longer axial length, the study supports a potential role of the EGFR signalling pathway activation in human axial myopia. The inverse relationship between VEGF-A concentration and longer axial length agrees with a protective effect of axial myopia against diabetic retinopathy and age-related macular degeneration.