Discovery Of Novel Non-Invasive Tear Metabolic Markers To Identify The Type Of Infection In Post-Operative Endophthalmitis

Endophthalmitis is a rare, but serious, postoperative complication of cataract surgery leading to vision loss. Increased inflammation causes retinal tissue damage in endophthalmitis and has been linked to altered metabolic activity. The mechanisms regulating the inflammation still remain elusive. The aim of the study was to investigate the change in the expression of metabolites in tears in different type of infections and correlate with the clinical parameters in post operative endophthalmitis 

Patients with post-operative bacterial(n=15), viral(n=3), fungal(n=5), mixed endophthalmitis(n=5) and post-operative inflammation(n=5) were included in this case-control study. We performed non-targeted metabolomic analysis of aqueous /vitreous humor/tear samples using UPLC coupled to time-of-flight mass spectrometer (LC-MS/MS). For functional and pathway analysis databases such as Kyoto Encyclopedia of Genes and Genomes (KEGG) and Metaboanalyst were utilized.

Aqueous/Vitreous humor/Tear metabolomic profiles could well distinguish endophthalmitis condition from controls. Though there were differences in the identification of metabolites between different samples, there was a significant overlap of biological pathways. Distinct metabolites were identified which could differentiate between the type of infection. In pathway analysis, Oxidative Phosphorylation, Phenylalanine metabolism and Fatty acid metabolism were highly impacted, implying that these metabolic markers play important roles in the regulation of these pathways. 

This study identified valuable metabolic biomarkers and pathways that differentiate between different pathogen induced endophthalmitis and may facilitate an improved understanding of it’s pathogenesis. Moreover, the host-directed therapeutics and validation are needed to complement pathogen-targeted approaches to treat ocular infections.