Research suggests that a grape-derived compound, piceatannol, may offer a new approach to preventing retinal damage in diabetes by targeting inflammation and preserving the blood-retinal barrier, with early studies in mice showing encouraging results.
A grape-derived compound may point to a new way of protecting the retina in diabetes, according to research published in the Journal of Translational Medicine. In work led by Yuanyuan Tu and Manhui Zhu at Soochow University in Suzhou, China, piceatannol reduced retinal damage in diabetic mice by calming immune activity inside the eye and helping preserve the blood-retinal barrier, the cellular seal that prevents fluid leakage from fragile retinal vessels.
Diabetic retinopathy remains one of the main causes of vision loss worldwide, and treatment has traditionally focused on the blood vessels themselves, using laser therapy, anti-VEGF injections or surgery to address leaking capillaries and abnormal vessel growth. But a growing body of research has shifted attention towards inflammation, particularly the role of microglia, the retina’s resident immune cells. When these cells are chronically activated in a high-glucose environment, they can release inflammatory molecules that worsen vascular injury and weaken the barrier that keeps the retina protected. Earlier studies have linked chemokines, a class of signalling proteins, to this process, including work showing that CCL2 helps drive immune-cell traffic into the diabetic retina and contributes to blood-retinal barrier breakdown.
The new study suggests that piceatannol acts on a related pathway involving CCL5, CCR5 and NF-κB. Using network pharmacology and transcriptomic analysis, the researchers narrowed hundreds of possible interactions down to a set of overlapping targets and identified CCR5 as a key receptor. Molecular docking and laboratory testing indicated that piceatannol could bind to CCR5, while the chemokine CCL5 was found to be increased in the diabetic retina. The researchers concluded that the compound appears to interrupt a signalling chain that otherwise pushes microglia towards a pro-inflammatory state.
That shift mattered for the retinal vessels. In diabetic mice treated with piceatannol, the researchers reported improved retinal thickness, fewer acellular capillaries and less leakage from blood vessels. In cell experiments, high glucose drove microglia into an inflammatory M1 state, which in turn reduced the tight-junction proteins zonula occludens-1 and Claudin-5 in human retinal endothelial cells. Those proteins are essential for holding the inner blood-retinal barrier together. Piceatannol reduced this inflammatory response and helped preserve the proteins, suggesting that its vascular benefit came indirectly through immune cells rather than by acting on endothelial cells alone.
The team also used gene-silencing and receptor-activation experiments to test whether CCR5 was central to the effect. When CCR5 was suppressed, piceatannol’s protective impact was blunted; when the pathway was switched back on, the benefits were reduced. That kind of gain-and-loss evidence strengthens the case that the CCL5/CCR5/NF-κB axis is not just associated with diabetic retinopathy but is part of the mechanism the compound influences. Still, the findings remain early-stage and were based on cell models and streptozotocin-induced diabetic mice, not people. Questions around dosing, bioavailability, retinal delivery and long-term safety remain unresolved, even as the study adds to interest in naturally occurring compounds as possible leads for future therapies.
Disclaimer: This content is for informational purposes only and is not intended to be a substitute for professional medical judgment, advice, diagnosis, or treatment.
