Differences in Aqueous Concentrations of Cytokines in Macular Edema Secondary to Branch and Central Retinal Vein Occlusion

Purpose

This study investigates the differential aqueous concentrations of interleukin 6, 8, 1β (IL-6, IL-8, IL-1β, respectively), 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 as a result of a branch retinal vein occlusion (BRVO) or central retinal vein occlusion (CRVO).

Principal Findings

Significantly higher concentrations of IL-6, IL-8, IL-1β, TGF-β, bFGF, SAA, and VEGF were found in the aqueous humor of CRVO and BRVO patients than in the aqueous humor of control patients. A significant correlation was observed between the concentration of bFGF and the inner central macular thickness (CMT) of BRVO patients (r = 0.688; P = 0.02). A significant correlation was observed between the concentration of SAA and both the full and outer CMT of the ischemic group (r = 0.545 and 0.683, respectively; P = 0.04 and 0.01, respectively). In the non-ischemic group, the level of IL-6 was significantly associated with inner CMT (r = 0.560; P = 0.03). The full and outer CMT was significantly reduced in CRVO patients when compared with BRVO patients (P = 0.02 and 0.02, respectively) after injection of intravitreal bevacizumab (IVB) at 4 weeks.

Significance

Serum amyloid A as a major protein involved in the acute and chronic stages of inflammation, and IL-6 and bFGF were significantly associated with the extent of macular edema in patients with RVO. Besides VEGF, other inflammatory cytokines and angiogenesic factors may be associated with RVO. This finding may have implications for the medical treatment of RVO.