Oxidative Stress and Inflammatory Biomarkers in Aqueous Humor and Blood of Patients with Leber’s Hereditary Optic Neuropathy

Leber's hereditary optic neuropathy (LHON) is a mitochondrial disorder that causes visual impairment due to the degeneration of retinal ganglion cells. Oxidative stress (OS) and inflammatory cytokines have been implicated in its pathophysiology. We investigated, for the first time, the presence of OS biomarkers and inflammatory cytokines in the aqueous humor and peripheral blood of LHON patients compared to controls, aiming to identify potential clinical biomarkers for diagnosis and disease monitoring. A total of 38 participants were enrolled in a single-center, retrospective observational study, including 17 genetically confirmed LHON patients from different Spanish regions and 21 controls. OS biomarkers and inflammatory cytokines were quantified using spectrophotometry and fluorimetry techniques. Statistical analyses were performed to compare groups and to assess the discriminatory performance of biomarkers in identifying affected individuals. Compared to controls, LHON patients exhibited significantly higher levels of AOPP, LOOH, nitrotyrosine, GPX, GRD, and OX/AntiOX ratio in both aqueous humor and serum. Among these, serum LOOH levels and the OX/AntiOX ratio were the most reliable for identifying patients affected, with high sensitivity and specificity. However, additional data on serum IL-1ra are required to confirm its potential as an effective classifier. These findings highlight novel candidate biomarkers for the diagnosis and monitoring of LHON progression.