Fangying Song,1 Yan Qi,1 Wenhui Ma,1 Jun Li,1 Yan Gao,1 Xiubin Ma1,2 

1State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, People’s Republic of China; 2Department of Ophthalmology, Qingdao Eye Hospital of Shandong First Medical University, Qingdao, People’s Republic of China

Correspondence: Xiubin Ma, Department of Ophthalmology, Qingdao Eye Hospital of Shandong First Medical University, 5 Yan’er dao Road, Qingdao, 266071, People’s Republic of China, Tel +86 532 85876380, Email maxiubin2005@126.com

Purpose: Emerging evidence suggests an association between ocular microbiota dysbiosis and ophthalmic diseases; however, the role of the posterior segment microbiome in diabetic retinopathy (DR) remains poorly characterized. In this study, we characterized the vitreous microbiome of patients with proliferative diabetic retinopathy (PDR) and systematically compared its microbial community structure with that of healthy controls.
Methods: A cohort of 19 PDR patients with type 2 diabetes mellitus and 19 non-DR controls were enrolled, with vitreous samples obtained through vitrectomy. Vitreous microbial composition was characterized using 2bRAD-M sequencing technology, enabling species-level taxonomic resolution. The comparison of dominant taxa, biomarker analysis and metabolic pathway differences between the two groups were further explored.
Results: The results of microbiome profiling revealed significant compositional differences in the vitreous core microbiome of PDR patients compared to controls, potentially associated with enhanced activity in membrane transport, nucleotide metabolism and carbohydrate metabolism pathways. LEfSe analysis identified 536 distinctive biomarkers of the two groups. At species level, the PDR group had significantly lower relative abundances of CAG− 485_sp009775375, Akkermansia_muciniphila and Bacteroides_acidifaciens, compared with control group.
Conclusion: This is the first study confirming the microbiota in human vitreous fluid samples by 2bRAD-M sequencing. These findings suggest a potential link between vitreous microbial dysbiosis and PDR, offering novel insights for future mechanistic investigations into DR.

Keywords: proliferative diabetic retinopathy, vitreous fluid, microbiota, 2bRAD-M