Relationship between human symbiotic microbiota and the occurrence and development of glaucoma

Human commensal microbiota exists in the gastrointestinal tract, oral cavity, ocular surface, and intraocular organs.Gastrointestinal commensal microbiota can cause glaucomatous optic nerve damage through autoimmune injury mechanisms, inflammation, or oxidative stress.The imbalance of intestinal microbiota represented by Helicobacter pylori infection may affect the function of trabecular cells by releasing inflammatory mediators and vasoactive substances.The resulting active metabolites affect the oxidative stress and apoptosis of trabecular cells.Autoimmune activation of glial cells leads to apoptosis of retinal ganglion cells.The imbalance of oral symbiotic microbiota can mediate the activation of microglia in the retina and optic nerve and the loss of retinal ganglion cells through the body’s immune response.Bacterial products’ toxic effects lead to optic nerve degeneration and induce chronic subclinical systemic inflammatory vascular endothelial cell dysfunction resulting in optic nerve damage.Ocular surface commensal microbiota mainly causes optic nerve damage through immune response, but whether it is related to intraocular diseases such as glaucoma remains to be studied.The imbalance of intraocular symbiotic microbiota is a specific characteristic of glaucoma.The changes in the intraocular immune microenvironment caused by intraocular microbiota may involve the complex effects of multiple inflammatory mediators and multiple molecular pathways.This article reviews the recent research in these areas, the extraocular, ocular surface, and intraocular symbiotic microbiota and their metabolites may directly or indirectly play a specific role in the pathogenesis of glaucoma.The comprehensive study and analysis of the microbiome of each part of the same individual in the future will provide a new angle to explore the cause and pathogenesis of glaucoma and provide new research ideas for the diagnosis and treatment of glaucoma.

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