Intravitreal bevacizumab effects on VEGF levels in distant organs: an experimental study

Purpose: The aim of this study was to determine the effects of single-dose intravitreal bevacizumab on the levels of vascular endothelial growth factor (VEGF) in serum and distant organs.

Methods: Adult New Zealand albino rabbits (n?=?40) were divided into experimental and control groups. Experimental rabbits received a single 0.05?ml intravitreal injection of 1.25?mg bevacizumab (Avastin) into the right eye, and control rabbits (n?=?8) received no injection. Following injection, group 1 rabbits (n?=?8) were sacrificed on day 1, group 2 rabbits (n?=?8) on day 7, group 3 rabbits (n?=?8) on day 14, and group 4 rabbits (n?=?8) on day 28; control rabbits were sacrificed on day 28. After sacrifice, samples of brain, heart, liver, kidney and blood were collected. Levels of VEGF in serum and tissue were measured using enzyme-linked immunosorbent assay. The presence of bevacizumab was evaluated by immunofluorescence staining in tissues.

Results: Positive bevacizumab immunoreactivity was observed in brain, heart and kidney. Serum VEGF levels significantly decreased in groups 3 and 4 compared with controls (p?p?Conclusions: Intravitreal bevacizumab not only may escape from the blood-retinal barrier and enter the general circulation, but also may be disseminated to distant organs. Our study demonstrates that a single dose of intravitreally injected bevacizumab decreases VEGF levels in serum and liver.