Purpose: To evaluate the association between vitreous inflammatory factors and the severity of diabetic macular edema (DME).
Design: Retrospective case-control study.
Participants: Fifty-three patients with DME, 15 patients with nondiabetic ocular disease, and 8 diabetic patients without retinopathy.
Methods: Vitreous fluid samples were obtained during vitreoretinal surgery, and the levels of vascular endothelial growth factor (VEGF), intercellular adhesion molecule (ICAM)-1, interleukin (IL)-6, monocyte chemotactic protein (MCP)-1, and pigment epithelium-derived factor (PEDF) were measured by enzyme-linked immunosorbent assay. Multivariate analysis was performed to assess the association of these factors with the severity of DME.
Main outcome measures: Vitreous fluid levels of inflammatory factors.
Results: Vitreous fluid levels of VEGF, ICAM-1, IL-6, and MCP-1 were significantly higher in patients with DME than in nondiabetic patients (P<0.05, all respectively) or diabetic patients without retinopathy (P<0.05, all respectively). In contrast, the PEDF level was significantly lower in patients with DME than in nondiabetic patients (P<0.05) or diabetic patients without retinopathy (P<0.05). Vitreous levels of VEGF, ICAM-1, IL-6, and MCP-1 were significantly higher in patients with hyperfluorescent DME than in those with minimally fluorescent DME (P = 0.0018, P = 0.0022, P = 0.0032, and P = 0.0053, respectively). Conversely, the vitreous level of PEDF was significantly lower in hyperfluorescent DME than in minimally fluorescent DME (P = 0.0134). Vitreous levels of VEGF, ICAM-1, IL-6, MCP-1, and PEDF were significantly correlated with the retinal thickness at the central fovea (P<0.0001, P<0.0001, P = 0.0282, P = 0.0009, and P = 0.0466, respectively). VEGF and ICAM-1 had a stronger influence on the severity of DME than the other factors (P = 0.0004 and P = 0.0372, respectively).
Conclusions: Vitreous fluid levels of VEGF, ICAM-1, IL-6, MCP-1, and PEDF were related to retinal vascular permeability and the severity of DME. VEGF and ICAM-1 had a stronger influence than the other factors.
Financial disclosure(s): The authors have no proprietary or commercial interest in any materials discussed in this article.