Retinal imaging biomarkers in eyes with geographic atrophy and association with systemic IL-6 levels

Abstract

Purpose : Interleukin-6 (IL-6) has been shown to be significantly altered in eyes with geographic atrophy (GA) compared with controls with no age-related macular degeneration (AMD). Elevated IL-6 has been previously associated with both presence and grown of GA lesions. However, the association of systemic IL-6 levels with imaging biomarkers in eyes with GA remains understudied. In this study, we examined the prevalence of imaging biomarkers in eyes with GA due to AMD and correlated these imaging biomarkers with systemic IL-6 levels.

Methods : Blood samples and baseline retinal images were collected on the same day for patients enrolled in the University of Colorado AMD Registry between 7/2014 and 7/2021. IL-6 levels were measured using a multiplex assay and categorized as <1.9 pg/mL or higher. Color fundus photos (CP), fundus autofluorescence (FAF), and optical coherence tomography (OCT) were reviewed for 33 qualitative imaging biomarkers (Table 1) by two trained image graders. Discrepancies were adjudicated by a third grader. Serum IL-6 levels were associated with the presence of imaging biomarkers using either the Chi-square test or Fisher’s exact test. Significant associations were defined as p < 0.01 due to multiple comparisons.

Results : In total, 96 eyes were included in our analysis. The frequency of imaging biomarkers across the entire cohort and the frequency of low levels of IL-6 in patients with and without certain imaging biomarkers are shown in Table 1. Imaging findings characteristic of advanced AMD, including presence of drusen, pigment migration, and incomplete or complete RPE and outer retinal atrophy, were found in the majority of patients in our cohort. Other imaging findings that were commonly noted were reticular pseudodrusen, outer retinal tubulations and retinal pseudocysts. Less common imaging findings included cuticular drusen, subretinal hyperreflective material, and pigmented epithelial detachments. There were no significant associations between low levels of IL-6 levels and any imaging biomarker.

Conclusions : In our cohort, systemic IL-6 levels—which have previously been shown to be associated with presence and progression of GA lesions—were not associated with qualitative retinal imaging biomarkers among patients with GA.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.