Researchers explore role of gut dysfunction in diabetic retinopathy

Researchers from the University of Alabama at Birmingham (UAB) have examined the role of the gut microbiome in diabetic retinopathy.

Writing in Gut, the researchers highlighted that restoring tryptophan metabolism helped to minimise vision loss as a result of diabetic retinopathy.

Senior author and professor at the UAB department of ophthalmology and visual sciences, Dr Maria Bartolomeo, highlighted that the findings open a new avenue for microbiome‑guided metabolic therapies in diabetic retinopathy.

“By targeting how tryptophan is absorbed in the gut, we were able to correct dysbiosis, reinforce gut barrier integrity, normalise incretin signaling and ultimately protect the retina,” she said.

In Type 2 diabetes, the intestine loses the ability to effectively absorb tryptophan – an amino acid that fulfils many biological functions including maintaining a healthy gut microbiome.

Dr Ram Prasad, first author of the study and senior scientist in the UAB department of ophthalmology and visual sciences, explained that a loss of tryptophan affects bacterial metabolism, leading to a reduction in the production of protective microbial metabolites.

The study identified that a key metabolite, indole‑3‑propionic acid (IPA), enters the bloodstream and accumulates in the retina in healthy individuals – playing a protective role. In mouse models of diabetic retinopathy, levels of IPA were reduced.

Researchers suggested that circulating IPA levels can act as a biomarker for diabetic retinopathy.

“Our findings suggest that restoring IPA to physiological levels has the potential to slow or counteract diabetic retinopathy progression and may reduce broader diabetic complications,” Prasad said.