Abstract
Purpose: :
To evaluate the minimum dose necessary to effect on vascular endothelial growth factor (VEGF) at intravitreally bevacizumab injection of Macaque eyes.
Methods: :
Bevacizumab (1.25 µg/50 µl), 1/1,000 as we usually use, was injected into the vitreous cavity of the right eyes of three cynomolgus macaques. Aqueous humor were obtained from the macaques just before injection and on days 1, 3, 7 and 14 after the injection. The bevacizumab and VEGF concentrations were measured using enzyme-linked immunosorbent assay. If VEGF did not decrease after the injection, the dose of intravitreal injection of bevacizumab was increased by 5 times.
Results: :
VEGF concentrations did not change when 1.25µg of bevacizumab was injected. It decreased to undetectable level when 6.25µg of bevacizumab was injected nad remained in undetectable level for 3-7 days. The half-life of 6.25 µg of intravitreally injected bevacizumab was 3.5 days in the aqueous humor, which was similar to 2.8days in the 1.25 mg of intravitreally injected bevacizumab in the previous study.
Conclusions: :
Intravitreal injection of 6.25 µg of bevacizumab seems to be enough to suppress VEGF, especially when it is used as pre-operative adjunct for vitrectomy for proliferative diabetic retinopathy.
Keywords: vascular endothelial growth factor • aqueous • injection