Purpose
The purpose of this study was to investigate the differential aqueous concentrations of interleukin 6, 8, 1β (IL-6, IL-8, IL-1β), serum amyloid A (SAA), transforming growth factor (TGF-β), basic fibroblast growth factor (bFGF), and vascular endothelial growth factor (VEGF) in eyes with macular edema due to non-proliferative diabetic retinopathy (NPDR) and proliferative diabetic retinopathy (PDR).
Methods
Eighteen eyes of 18 patients with NPDR, 8 eyes of 8 patients with PDR, and 10 eyes of 10 patients with non-diabetic ocular disease were included in the study sample. Aqueous humor samples were collected just before intravitreal injection, and were assessed for 7 cytokines using multiplex bead assay.
Results
Significantly increased concentrations of IL-6, IL-8, IL-1β, SAA, TGF-β, bFGF, and VEGF were found in the aqueous humor of NPDR and PDR patients compared with control samples. Higher concentrations of IL-1β were measured in the aqueous humor of patients with PDR compared with NPDR (P=.007). A significant correlation was observed between concentration of VEGF and both the full and outer central macular thickness of NPDR patients (r=.513 & .515; P=.030 & .029, respectively). In the PDR group, the level of IL-8 was significantly associated with inner central macular thickness (r=.763, P=.028). Following the injection of intravitreal bevacizumab at 4 weeks, the full and outer central macular thickness was significantly reduced in NPDR patients compared with PDR patients.
Conclusions
Intraocular concentration of VEGF was significantly associated with both full and outer central macular thickness in NPDR patients whose macular edema responded well to anti-VEGF therapy. IL-1β and IL-8 promoting fibrosis was associated with macular edema in PDR patients, which may explain why intravitreal bevacizumab single injection did not markedly improve macular edema in PDR patients.
Keywords: 499 diabetic retinopathy •
585 macula/fovea •
467 clinical laboratory testing