Cytokines associated with hemorrhage in proliferative diabetic retinopathy

To investigate aqueous cytokine levels in association with hemorrhage in proliferative diabetic retinopathy (PDR) in patients with type 2 diabetes mellitus.

Sixty-six eyes with treatment-naïve PDR, including 26 hemorrhagic and 40 nonhemorrhagic eyes were included in this institutional study. Aqueous humor levels of interleukin (IL)-1b, IL-6, IL-8, IL-10, monocyte chemoattractant protein (MCP)-1, tumor necrosis factor (TNF)-α, vascular endothelial growth factor (VEGF), and soluble VEGF receptor-1 were obtained by multiplex bead assay. Visual acuity and hemorrhage area measurements were obtained, and correlations between cytokine levels and hemorrhage were identified.

Levels of MCP-1, TNF-α, and VEGF were higher in hemorrhagic eyes (1506.77 vs. 2131.31 pg/mL, 0.43 vs. 0.63 pg/mL, and 103.96 vs. 206.96 pg/mL; P = 0.050, 0.022, and 0.027, respectively). The levels of IL-8, MCP-1, TNF-α, and VEGF showed positive correlation with visual acuity (P = 0.019, 0.015, 0.001, and 0.014, respectively). The hemorrhage area revealed positive correlation with TNF-α and VEGF levels (P = 0.001 and < 0.001, respectively).

The presence and amount of hemorrhage in PDR were associated not only with VEGF concentration, but also with the levels of certain inflammatory cytokines, suggesting a role of both VEGF and inflammation in hemorrhagic eyes.