Down‐regulated tear film proteins in neovascular age‐related macular degeneration are involved in the regulation of protein clearance, inflammation, neovascularization and apoptosis

Abstract

PurposeAge‐related macular degeneration (AMD) is a multifactorial disease, and a leading cause of blindness elderly in the developed countries. In its neovascular form, an immediate treatment is required to maintain the best possible vision. The better understanding of the mechanisms underlying AMD is needed to create a both new treatment protocols and diagnostic tests. Tear film is an easily accessible fluid that can be obtained from each patient during the routine ophthalmic appointment. Changes in tear film proteomic composition have been reported in various ophthalmic and systemic diseases. There is an evidence that the acute form of wet AMD with subretinal fluid may reflect in a tear film composition.MethodsTear film was collected with Schirmer strips from the patients with neovascular AMD and sex‐ and age‐matched control group. Two‐dimensional electrophoresis was performed followed by MALDI‐TOF mass spectrometry identification of differential proteins. Quantitative analysis of the differentiating electrophoretic spots was done with 2 Delta software. Metabolic pathways associated with those proteins were identified with Panther GO software.ResultsAltogether, 16 differentially expressed proteins were identified. Of those, 14 were downregulated, while 2 showed upregulation in the tear film of wet AMD patients. Pathway analysis revealed multiple pathways involving protein clearance, inflammation, neovascularization and apoptosis.ConclusionsDifferentially expressed proteins and theirs signaling pathways identified in tear film coincide with impaired protein clearance, persistent inflammation, neovascularization and cell death. Tear film protein analysis provides a novel way to screen AMD‐related biomarkers.