Prospective Cytokine Profiling in Aqueous Humor Reveals a Proinflammatory Microenvironment in Highly Dense Nuclear Cataracts.

Abstract

Purpose To investigate if the cytokine profile in the aqueous humor (AH) of cataract patients varies according to cataract type and severity. Methods This prospective study included 397 eyes of 397 patients (median age, 76 years; range, 30-94 years) who underwent standard small-incision phacoemulsification surgery. Cataracts were graded using the LOCS III system: mild (≤3), moderate (3.5-5), and severe (≥5). Biometric measurements from the IOL master 700 (Zeiss, Oberkochen, Germany) were used to differentiate between thick (>4.5 mm) and thin lenses. Information about age, gender, and self-reported diseases was obtained from patient records. Eleven different proteins were measured in AH using a multiplex cytokine assay (AYOXXA Biosystems, Cologne, Germany), including IL- 6, IL-8, angiopoietin 2, C-reactive protein (CRP), vascular endothelial growth factor A (VEGF-A), platelet-derived growth factor BB, placental growth factor, CXCL12, CXCL13, and CXCL10. Statistical analysis was performed using R and included nonparametrical testing, linear regression, and k-means clustering. Results Higher nuclear LOCS grades correlated with increased levels of CCL2 (360 vs. 387 vs. 517 pg/mL, P < 0.001), VEGF-A (270 vs. 292 vs. 390 pg/mL, P = 0.012), IL-8 (3.1 vs. 4.2 vs. 5.7 pg/mL, P = 0.018), and CXCL10 (52 vs. 61 vs. 90 pg/mL, P = 0.003). No associations were observed for cortical and subcapsular cataracts. Thicker lenses were associated with significantly increased levels of CRP, CXCL10, CXCL12, IL-6, IL-8, and VEGF-A. Conclusions The cytokine profile of AH varies based on cataract grading and lens thickness. In highly dense nuclear cataracts, CCL2, VEGF-A, IL-8, and CXCL10 were elevated.