Inhibition of proliferation of retinal vascular endothelial cells more effectively than choroidal vascular endothelial cell proliferation by bevacizumab.
OBJECTIVE
To evaluate the differential inhibitory effects of bevacizumab on cell proliferation of vascular endothelial growth factor (VEGF)-stimulated choroidal vascular endothelial cells (CVECs) and retinal vascular endothelial cells (RVECs)in vitro.


METHODS
VEGF (400 ng/mL) enriched CVECs and RVECs were treated with escalating doses of bevacizumab (0.1, 0.5, 1, 1.5 and 2 mg/mL). Cell proliferation changes were analyzed with WST-1 assay and trypan blue exclusion assay at 48, 72h and 1wk. Morphological changes were recorded with bright field microscopy.


RESULTS
VEGF enriched RVECs showed significantly more decline of cell viability than CVECs after bevacizumab treatment. One week after treatment, RVEC cell proliferation decreased by 29.7%, 37.5%, 52.8%, 35.9% and 45.6% at 0.1, 0.5, 1.0, 1.5 and 2 mg/mL bevacizumab respectively compared to CVEC proliferation decrease of 4.1%, 7.7%, 2.4%, 4.1% and 17.7% (P<0.05) by WST-1 assay. Trypan blue exclusion assay also revealed similar decrease in RVEC proliferation of 20%, 60%, 73.3%, 80% and 93.3% compared to CVEC proliferation decrease of 4%, 12%, 22.9%, 16.7% and 22.2% respectively (P<0.05). The maximum differential effect between the two cell types was observed at bevacizumab doses of 1.0 and 1.5 mg/mL at all time points. RVECs were 22 fold more sensitive (P<0.01) compared to CVECs (52.8%vs2.4%) at concentration of 1.0 mg/mL, and 8.7 fold more at 1.5 mg/mL (35.9%vs4.1%) 1wk after treatment (P<0.05 respectively).


CONCLUSIONS
VEGF-enriched RVECs are more susceptible to bevacizumab inhibition than CVECs at clinically used dosage of 1.25 mg and this differential sensitivity between two cell types should be taken into consideration in dosage selection.
Department of Ophthalmology, University of Florida, College of Medicine, Jacksonville, FL 32209, USA.
Bharani Krishna
BK
Mynampati
Department of Ophthalmology, University of Florida, College of Medicine, Jacksonville, FL 32209, USA.
Kumar
K
Sambhav
Department of Ophthalmology, University of Florida, College of Medicine, Jacksonville, FL 32209, USA.
Sandeep
S
Grover
Department of Ophthalmology, University of Florida, College of Medicine, Jacksonville, FL 32209, USA.
Kakarla V
KV
Chalam
bevacizumab; choroidal vascular endothelial cells; retinal vascular endothelial cells