Application of multiplex cytometric bead array technology for the measurement of angiogenic factors in the vitreous.

PURPOSE This study was carried out to compare cytometric bead array (CBA) technology with conventional enzyme linked immunosorbent assay (ELISA) for the measurement of both vitreous and serum concentrations of interleukin-8 (IL-8), vascular endothelial growth factor (VEGF), and angiogenin (ANG) in diabetic and non-diabetic patients. METHODS Measurement of vitreous and serum concentrations of IL-8, VEGF, and ANG using both ELISA and CBA was performed in 26 probands (13 diabetics and 13 non-diabetic control subjects). RESULTS Vitreous and serum concentrations of IL-8, VEGF, and ANG determined by CBA showed a strong correlation with those measured by ELISA. Vitreous levels of IL-8, VEGF, and ANG were significantly higher in diabetics compared to non-diabetic control subjects. No significant correlation between vitreous and serum levels of any of the investigated parameters were found in either diabetics or control individuals. CONCLUSIONS The present study is the first to utilize cytometric bead array technology for the measurement of angiogenic factors in the vitreous. Measurements obtained by ELISA and CBA technologies were highly correlated for IL-8, VEGF, and ANG in both vitreous and serum samples. Diabetic individuals showed significant elevation of IL-8, VEGF, and ANG in the vitreous but not in serum samples compared to control subjects. The most striking advantage of the CBA technology is the fact that numerous parameters can be measured in parallel using a comparatively small sample volume. It is therefore more rapid and cost effective than ELISA technology. CBA technology is a new, accurate method to measure IL-8, VEGF, and ANG in the vitreous.