Cytokine profiles of aqueous humor from sequential bilateral cataract surgery: Impact of diabetes on inflammatory responses

We investigated aqueous humor (AH) cytokine profiles in first- and second-operated eyes of patients undergoing sequential bilateral cataract surgery and explored these profiles according to diabetes mellitus (DM) status. This retrospective, within-subject, comparative observational study included 71 patients, comprising 39 without DM and 32 with DM but without diabetic retinopathy, who underwent uneventful sequential bilateral cataract surgery within a 2-week interval. The concentrations of vascular endothelial growth factor, angiopoietin-2, placental growth factor, interleukin (IL)-6, IL-8, monocyte chemoattractant protein-1 (MCP-1), and transforming growth factor-β2 (TGF-β2) in the AH were analyzed. In patients without DM, mean IL-6 concentrations were nominally lower in the second eye than in the first eye (P = 0.041), although this finding did not remain statistically significant after FDR adjustment. In patients with DM, there were no significant differences in cytokine concentrations between the first and second eyes. The eye-order × DM interaction for IL-6 was not statistically significant (P = 0.644). Compared with patients without DM, higher MCP-1 and TGF-β2 concentrations were observed in the first eye and higher TGF-β2 concentrations in the second eye, with the strongest statistical evidence observed for first-eye TGF-β2, which remained significant after FDR adjustment. Differences in AH cytokine profiles were observed between patients with and without DM during sequential bilateral cataract surgery. The lower mean IL-6 concentration observed in the second eyes of patients without diabetes represents a novel, although exploratory, observation. Whether this finding reflects pre-existing inter-eye variability or a biological response associated with sequential surgery remains to be determined.