Researchers in China have identified a small RNA molecule in the blood whose levels track closely with the severity of diabetic retinopathy, one of the most common microvascular complications of type 2 diabetes. The study, published in BMC Ophthalmology, found that patients with retinopathy had significantly lower circulating levels of a microRNA called miR-10b-5p compared with diabetic patients whose retinas were unaffected, and that the molecule showed meaningful accuracy as a diagnostic marker for the condition.
The research team recruited 270 patients with type 2 diabetes. Of these, 90 had diabetes without retinopathy, 93 had non-proliferative diabetic retinopathy, the earlier stage of the disease, and 87 had proliferative diabetic retinopathy, the advanced stage. Using quantitative reverse transcription PCR, the researchers measured the expression of miR-10b-5p and PTBP1 in serum samples from all three groups.
The results showed a clear pattern. Serum miR-10b-5p was significantly lower in patients with diabetic retinopathy than in those without the condition, and levels were lowest of all in the proliferative group. When the researchers tested how well the molecule could distinguish between patients with and without retinopathy, it achieved an area under the curve, or AUC, of 0.856. The molecule also showed negative correlations with serum VEGF, a growth factor involved in the abnormal blood vessel growth that drives the disease, and with endothelial cell counts.
Statistical analysis strengthened the clinical relevance of the finding. Low levels of miR-10b-5p emerged as an independent risk factor for proliferative diabetic retinopathy, with an odds ratio of 0.109, meaning that reduced expression was associated with substantially higher odds of having the advanced form of the disease. The authors concluded that downregulated serum miR-10b-5p is associated with diabetic retinopathy and proliferative disease, suggesting its potential utility as a diagnostic biomarker.
Beyond the diagnostic question, the study probed the molecular machinery behind the association. The researchers constructed a laboratory model of high-glucose injury using human retinal microvascular endothelial cells, the cells that line the tiny blood vessels of the retina. When these cells were exposed to high glucose concentrations, their expression of miR-10b-5p dropped, mirroring what the researchers had observed in the blood of patients.
To test whether restoring the molecule could protect the cells, the team transfected the high-glucose-treated cells with miR-10b-5p mimics, synthetic molecules that raise the level of the microRNA inside the cells. The overexpression partially reversed the damage caused by the glucose exposure: cell viability and migratory capacity, both of which had declined under high-glucose conditions, recovered to a meaningful degree, and the elevated rate of apoptosis fell back. These experiments suggest that miR-10b-5p plays a protective role in retinal endothelial cells under diabetic conditions, at least in the laboratory setting.
The researchers then turned to how the molecule exerts its effects. Using a dual-luciferase reporter assay, a technique that reveals whether a microRNA can directly bind a predicted target sequence, the team demonstrated that miR-10b-5p directly targets PTBP1 and inhibits it. The functional importance of this relationship became clear in a complementary experiment. When the researchers introduced PTBP1 overexpression plasmids into the cells, forcing production of the protein that miR-10b-5p normally suppresses, the protective effects of the microRNA on cell viability, migration and survival under high-glucose conditions were reversed. This result positions PTBP1 as the functional mediator through which miR-10b-5p protects retinal endothelial cells from glucose-induced dysfunction.
The authors caution that the cell experiments were conducted in vitro and that the protective mechanism they identified warrants further in vivo investigation before any therapeutic implications can be drawn. The findings support the molecule’s promise as a biomarker rather than an established treatment. Published on 4 November 2026 as an open-access article in BMC Ophthalmology, the research was led by Weina Ren, Siying Xiong, Jing Song and Jiaoyan Xie, with the article shared early to provide faster access to peer-reviewed, accepted research.
Whether restoring the molecule in patients could slow the disease itself remains an open question that the laboratory data alone cannot answer, but the identification of the miR-10b-5p–PTBP1 axis gives researchers a concrete molecular pathway to investigate in future studies.
Subject of Research: The role of the microRNA miR-10b-5p as a diagnostic biomarker for diabetic retinopathy and its protective mechanism targeting PTBP1 in retinal endothelial cells
Article Title: miR-10b-5p alleviates type 2 diabetic retinopathy by targeting PTBP1
Article References: Ren, W., Xiong, S., Song, J., & Xie, J. (2026). miR-10b-5p alleviates type 2 diabetic retinopathy by targeting PTBP1. BMC Ophthalmology. https://doi.org/10.1186/s12886-026-05383-7
Image Credits: AI Generated
DOI: 10.1186/s12886-026-05383-7
Keywords: miR-10b-5p, diabetic retinopathy, type 2 diabetes, PTBP1, microRNA, biomarker, retinal endothelial cells, high glucose, VEGF, diagnostics, BMC Ophthalmology, qRT-PCR
News Source: Ophelia Keating. (November 4, 2026). Blood microRNA miR-10b-5p linked to diabetic retinopathy severity. Scienmag.
