PRIMARY OPEN ANGLE GLAUCOMA: MECHANISMS OF PATHOGENESIS AND GENETIC PREDISPOSITION. Review

Abstract

Relevance. Primary open-angle glaucoma (POAG) is a progressive optic neuropathy with loss of retinal ganglion cells (RGCs) and narrowing of the visual fields in the eyes with a gonioscopic open angle. The main mechanisms of this are increased intraocular pressure (IOP), circulatory disorders, trabecular meshwork (TM), ischemic metabolic disorders and chronic inflammation. However, questions about the role of POAG genetic predisposition remain open.
 Objective: analysis of current data on the mechanisms of pathogenesis of progressive neuropathy in POAG and the role of genetic predisposition.
 Methods. The analysis of scientific publications in open international electronic scientometric databases: Scopus, PubMed, Web of Science, Google Scholar, SID, MagIran, IranMedex, IranDoc, ScienceDirect, Embase by keywords (a total of 67 sources). Search depth – 10 years (2012-2022).
 Results. There are more than 60 million glaucoma patients in the world, 20% of whom have an incurable stage. By 2040, the number of patients is projected to increase to 112 million, with POAG accounting for 75% of cases. Among the main mechanisms of glaucoma, an important role belongs to chronic inflammation and immune damage, which occur in response to ischemic injury. Prolonged inflammatory process leads to hypersecretion of inflammatory mediators and infiltration of inflammatory cells into ischemic tissue, which aggravates the effects of increased IOP and ischemia. It is known that mutations in the gene of Toll-like receptor 4 (TLR4) are associated with both infectious and non-infectious diseases, including POAG: activation of TLR4 initiates TM fibrosis, causes increased IOP, activates RGCs apoptosis in the model of acute glaucoma. TLR4 ligands, such as heat shock proteins and lipopolysaccharides are candidate antigens for glaucoma. TLR4 overexpression at retinal microglia and astrocytes induce an innate immune response through NF-κB activation, which enhances the expression of proinflammatory cytokines.
 Conclusions. A promising direction is to study the contribution of TLR4 mutations to the POAG mechanisms, which will identify the mechanisms of immune disorders and establish the genetic risk of individual mutations in different ethnic groups.