Elevated advanced glycation end products are associated with subfoveal ellipsoid zone disruption in diabetic macular edema

PURPOSE: Advanced glycation end products (AGEs), due to increased production and a slow turnover rate, serve as mediators of “metabolic memory” even after the resolution of hyperglycemia. A prospective study was undertaken to evaluate the association of AGEs with subfoveal ellipsoid zone (EZ) disruption in diabetic macular edema (DME). METHODS: A tertiary-care-center-based cross-sectional study included 40 consecutive cases with DME and 20 healthy controls in the age group of 40–65 years. All the study subjects underwent spectral-domain optical coherence tomography (SD-OCT) for cross-sectional imaging of the retina. The EZ was defined as a hyperreflective band below the external limiting membrane. The disruption of EZ was graded as intact EZ and disrupted EZ. Serum AGEs were assessed by assay of N(ε)-carboxymethyl-lysine (N(ε)-CML) using the standard protocol. Data were analyzed statistically. RESULTS: Subfoveal EZ disruption was noted in 80% (32/40) of the cases of DME. In the cases without EZ disruption, visual acuity (LogMAR VA) was 0.60 ± 0.52, whereas in cases with EZ disruption, LogMAR VA was 0.96 ± 0.56 (P < 0.001). In the cases without EZ disruption, N(ε)-CML was 94.31 ± 57 ng/mL, whereas in cases with EZ disruption N(ε)-CML was 120.64 ± 71.98 ng/mL (P < 0.001). CONCLUSION: In DME, increased levels of AGEs are significantly associated with EZ disruption on SD-OCT.