Inflammatory cytokines and retinal nonperfusion area in quiescent proliferative diabetic retinopathy

Purpose: We sought to investigate the association between inflammatory cytokine levels and retinal capillary nonperfusion area in eyes with quiescent proliferative diabetic retinopathy (PDR). Methods: Samples of aqueous humor were collected from 67 eyes (n = 42 patients) with treatment-naïve PDR. Levels of interleukin (IL)-10, IL-1β, IL-6, IL-8, monocyte chemoattractant protein 1 (MCP-1), and tumor necrosis factor–α (TNF-α) were obtained using multiplex bead assay. Areas of capillary nonperfusion at the posterior pole and peripheral retina were measured via ultra-widefield fluorescein angiography and correlated with cytokine levels. Results: The levels of IL-10, IL-6, IL-8, MCP-1, and TNF-α were positively correlated with the nonperfusion area of the peripheral retina (r = 0.298, 0.401, 0.265, 0.435, and 0.393; all P ≤ 0.030). There were positive correlations between IL and 10, IL-6, IL-8, MCP-1, and TNF-α (all R ≥ 0.247; all P ≤ 0.043). IL-1β did not show a significant correlation with the nonperfusion area (P = 0.972 for posterior pole and 0.392 for periphery) but was positively correlated with TNF-α (r = 0.334; P = 0.006). Conclusions: An increased level of inflammation was observed in PDR eyes with larger nonperfusion areas, which suggests inflammation as a possible target for suppressing PDR progression associated with nonperfusion.