Purpose: The purpose of this study was to determine the concentrations of angiogenic and inflammatory markers in human eyes with diffuse diabetic macular edema before and during therapy with intravitreal bevacizumab and their association with disease activity.
Methods: In a prospective clinical trial, 10 eyes of 10 consecutive patients with vision loss because of diabetic macular edema were compared with 10 eyes of 10 age-matched controls. Bevacizumab was administered at baseline; retreatments were given monthly according to disease activity. During a follow-up of 6 months, aqueous humor samples were taken each time intravitreal therapy was administered. A multiplex assay was used for measurement of 12 different growth factors and cytokines.
Results: Aqueous humor of eyes with diabetic macular edema demonstrated a significantly increased expression of monocyte chemoattractant protein-1 and interleukin-8 and higher, but not significant, levels of interleukin-6 and vascular endothelial growth factor. Intravitreal therapy with bevacizumab resulted in a significant decrease of vascular endothelial growth factor below physiologic levels. This change was not associated with clinical disease activity as measured by visual acuity and central retinal thickness.
Conclusion: Eyes with diabetic macular edema showed a different profile of monocyte chemoattractant protein-1 and interleukin-8 as compared with controls. The intraocular vascular endothelial growth factor expression decreased significantly after the first intravitreal injection of bevacizumab; this reduction was prolonged by consecutive monthly retreatment.