Protocol and Methods Applicable to Retinal Vascular Diseases

Lipidomics is a branch of omics biology that enables the characterization and determination of different lipid classes. Mass spectrometry is a widely used tool to identify and obtain qualitative and quantitative measurements of the range of lipid species in various cell/tissue types. Human retina is highly rich in different classes of lipids that are liable to undergo modification such as oxidation, isomerization, peroxidation, and hydroxylation due to continuous metabolic activity in response to light photons. Alterations in lipid metabolism are associated with retinal diseases such as age-related macular degeneration, diabetic retinopathy, and retinopathy of prematurity. However, a clear understanding on the type of lipids/alterations involved in these diseases is not established yet. The unavailability of suitable biological retinal tissue need for this research has prompted us to explore vitreous humor and tear film for studying lipidomic alterations in different ocular diseases. Subjecting the lipid extract to tandem mass spectrometry further gives qualitative and quantitative lipidome of the diseased tissue. While the mass spectrometry approaches for lipid profiling have been adequately described, the present chapter focusses on a simplified protocol for extracting sufficient lipids/metabolites from vitreous humor and tear samples obtained from patients and their subsequent mass spectrometry analysis.