Plasma levels of vascular endothelial growth factor and pigment epithelium-derived factor before and after intravitreal injection of bevacizumab.

AIMS: To determine the level of vascular endothelial growth factor (VEGF) and pigment epithelium-derived factor (PEDF) in the plasma of patients with proliferative diabetic retinopathy before and after an intravitreal injection of bevacizumab.
METHODS: Eleven patients with type 2 diabetes and control of 30 non-diabetic patients were studied. The 11 eyes of 11 patients received an injection of bevacizumab (1.25 mg). Samples of blood were collected just before the injection, and after 1 day, 7 days and 1 month. The concentrations of VEGF and PEDF in the plasma were measured by ELISA.
RESULTS: The VEGF concentration before the injection was 114.0 pg/ml. It was significantly reduced to 9.7 pg/ml after 1 day, to 11.7 pg/ml after 7 days and to 25.9 pg/ml even after 1 month (p<0.001, p<0.001, p<0.001, respectively). The PEDF concentration before the injection was 7.2 microg/ml. It was significantly reduced to 5.8 microg/ml after 1 day, to 5.8 microg/ml after 7 days and to 6.3 microg/ml after 1 month (p<0.001, p<0.001, p>0.05, respectively).
CONCLUSIONS: The decreased levels of blood VEGF after an intravitreal injection of bevacizumab indicate that bevacizumab enters the general circulation and may also affect the PEDF levels. Thus, we should carefully examine patients for systemic changes and the fellow eye after an intravitreal injection of bevacizumab.