Short chain fatty acids (SCFAs) are produced by gut microbiota as fermentation products of digestion-resistant oligosaccharides and fibers. Their primary roles are functioning as major energy sources for colon cells and assisting in gut homeostasis by immunomodulation. Recent evidence suggests that they affect various organs both at cellular and molecular levels, and regulate functions in distance sites including gene expression, cell proliferation, cell differentiation, apoptosis and inflammation. In this study, we examined whether SCFAs are present in the mouse eye and whether SCFAs affect inflammatory responses of the eye and retinal astrocytes (RACs). We observed that intra-peritoneal injected SCFAs were detected in the eye and reduced intraocular inflammation induced by lipopolysaccharide (LPS). Moreover, SCFAs displayed two disparate effects on LPS-stimulated RACs - namely, cytokine and chemokine production was reduced, but the ability to activate T cells was enhanced. Our results support the existence of gut-eye cross talk and suggest that SCFAs can cross the blood-eye-barrier via the systemic circulation. If applied at high concentrations, SCFAs may reduce inflammation and impact cellular functions in the intraocular milieu.

Rhodopsin-mediated autosomal dominant retinitis pigmentosa (RP) is the most common cause of RP in North America. There is no proven cure for the disease, and multiple approaches are being studied. Gene therapy is an evolving field in medicine and ophthalmology. In this review, we will go over the basic concept of gene therapy and the different types of gene therapy that are currently being studied to treat this disease.

Age-related macular degeneration (AMD) is a progressive degenerative disease of the central retina and the leading cause of severe loss of central vision in people over age 50. Patients gradually lose central visual acuity, compromising their ability to read, write, drive, and recognize faces, all of which greatly impact daily life activities. Quality of life is significantly affected in these patients, and there are worse levels of depression as a result. AMD is a complex, multifactorial disease in which age and genetics, as well as environmental factors, all play a role in its development and progression. The mechanism by which these risk factors interact and converge towards AMD are not fully understood, and therefore, drug discovery is challenging, with no successful therapeutic attempt to prevent the development of this disease. In this review, we describe the pathophysiology of AMD and review the role of complement, which is a major risk factor in the development of AMD.

Hyperreflective choroidal foci (HCF) are a finding on optical coherence tomography that may serve as a biomarker in various retinal and choroidal pathologies. These discrete hyperreflective spots, identified in various layers of the choroid, have been linked to inflammatory, vascular, and degenerative conditions. This review examines the clinical significance, histopathological correlation, and implications of HCF in various diseases, including diabetic retinopathy, age-related macular degeneration, Stargardt disease, choroideremia, Vogt-Koyanagi-Harada disease (VKH), idiopathic posterior uveitis, retinitis pigmentosa, and central serous chorioretinopathy (CSR), as well as non-pathological states. Although further studies are required to validate the findings in each pathology described herein, HCF may be used as a background prognostic marker of disease progression and therapeutic response, albeit with caution.

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