Evidence Suggesting the Role of Gut Dysbiosis in Diabetic Retinopathy

Abstract

Purpose Gut dysbiosis has been identified and tested in human trials for its role in diabetes mellitus (DM). The gut–retina axis could be a potential target for retardation of diabetic retinopathy (DR), a known complication of DM. This study reviews the evidence suggesting gut dysbiosis in DR. Methods The published literature in the past 5 years was reviewed using predetermined keywords and articles. The review intended to determine changes in gut microbiome in DR, the hypothesized mechanisms linking to the gut–retina axis, its predictive potential for progression of DR, and the possible therapeutic targets. Results The gut microbiota of people with DM differ from those without it, and the gut microbiota of people with DR differ from those without it. The difference is more significant in the former (DM versus no DM) and less significant in the latter (DM without DR versus DM with DR). Early research has suggested mechanisms of the gut–retina axis, but these are not different from known changes in the gut microbiome of people with DM. The current evidence on the predictive value of the gut microbiome in the occurrence and progression of DR is low. Therapeutic avenues targeting the gut–retina axis include lifestyle changes, pharmacologic inhibitors, probiotics, and fecal microbiota transplantation. Conclusions Investigating the therapeutic utility of the gut ecosystem for DM and its complications like DR is an emerging area of research. The gut–retina axis could be a target for retardation of DR but needs longitudinal regional studies adjusting for dietary habits.

Intraocular Microbiome in Diabetes and Diabetic Retinopathy: A Pilot Study

“…There was a gross reduction in the anti-inflammatory bacteria in the aqueous humour of people with DR. Incidentally, these observations are similar to our earlier ones with gut microbiome in people with DR but less obvious than the current study. In our earlier study on the gut microbiome, we noted a higher difference between controls and DM, and there was an overlap between DM and DR groups [7,8,32]. However, the current data on the intraocular microbiome show a wider separation across the DM and DR groups compared with the gut microbiome (Figs.…”

Anxiety and Depression in Patients with Diabetic Retinopathy

“…Lipopolysaccharide exposure in multiple systems caused progressive retinal thinning and a 3.5-fold increase in endothelial cell damage in hyperglycemic rats (43). Insulin resistance can also be explained by intestinal flora via GEA, and flora disruption lowers butyrate, impairs insulin sensitivity, and raises the prevalence of DR (44).…”

Vascular complications of diabetes: A narrative review

“…[27][28][29][30] Alongside these mechanisms, accumulating studies emphasized a reliable connection between gut microbiome and DR which is considered to be a "microbiota-gut-retina axis." [26,[31][32][33][34][35] The gut microbiota promotes the occurrence and development of DR through mechanisms such as inflammation, barrier dysfunction, vascular permeability, and metabolites. [26] Compared with healthy individuals, the intestinal microecology of patients with diabetes without retinopathy and DR patients is dysregulated.…”