Abstract
Purpose:
The biochemical pathways that drive Diabetic Macular Edema (DME) are only partially understood. Intra-vitreal injection of anti-Vascular Endothelial Growth Factor (VEGF) can reduce DME. We therefore examined the correlation of severity of DME to vitreous levels of VEGF A and its receptors in patients undergoing treatment.
Methods:
In-office vitreous aspirates (50-100 μL) were obtained from 20 eyes of 16 patients undergoing treatment for DME with Anti-VEGF agents during the period between 11/26/08 and 11/24/09 during an IRB approved study. Each vitreous sample was acquired immediately prior to intra-vitreal injection. All vitreous samples were investigated utilizing Reverse Phase Protein Microarray (RPPM) technology. Spectral Domain-OCT was conducted preceding treatment and maximum macular thickness (MMT), central macular thickness (CMT), and total volume (TV) were measured. Correlation of severity of DME to vitreous levels of VEGF A and its receptors was determined using Pearson’s Analysis.
Results:
The study included 31 samples obtained from 20 eyes of 16 subjects. Correlation coefficients between VEGF A and MMT, CMT, and TV were 0.0476, -0.0617, and 0.0064 respectively. VEGFR Y951 was found to have correlation coefficients of -0.0691, -0.1383, and -0.0912 with MMT, CMT, and TV respectively. VEGFR Y996 which was found to have correlation coefficients of -0.0249, -0.1064, and -0.0148 with MMT, CMT, and TV respectively. Lastly, VEGFR Y1175 was found to have correlation coefficients of 0.0138, -0.0922, and 0.0278 with MMT, CMT, and TV respectively.
Conclusions:
These findings suggest that the pathophysiology of DME may extend beyond this single pathway. Indeed DME may be far more multifactorial than previously recognized. Larger studies of vitreous biomarkers may help improve the understanding of DME.