IJUP08 - Universidade do Porto

Anti-Angiogenic Effects of Ranibizumab and Bevacizumab in
Age-Related Macular Degeneration: Effects on Human Endothelial
Cells
M. Ferreira-Pinto 1* , T. Taveira-Gomes 1* , A Carneiro 2 , M Falcão 2 , I. Azevedo 1 , F.
Falcão-Reis 2 , R. Soares 1
1 Department of Biochemistry, Faculty of Medicine of University of Porto, Portugal.
2 Department od Ophthalmology, Faculty of Medicina of University of Porto, São João Hospital,
Portugal
* The two authors contributed equally to the project
INTRODUCTION: Age-related macular degeneration (AMD) is the leading cause of
irreversible blindness over 50 years of age in developed countries. This pathology is
characterized by the development of abnormal choroidal blood vessels that proliferate
through the Bruch's membrane, invading the subretinal space, beneath the macula, which
causes severe and fast loss of vision. Angiogenesis, the formation of new blood vessels
from pre-existing ones, is accomplished by a huge number of pro-angiogenic growth
factors, such as vascular endothelial growth factor (VEGF). Recent reports claiming that
VEGF plays a crucial role in AMD-related angiogenesis rendered this growth factor a
major therapeutic target. Ranibizumab and bevacizumab are two therapeutic agents already
being used in the clinical pratice that block the action of VEGF. However, there are no
studies comparing the relative efficacy and safety in AMD patients.
OBJECTIVES: The purpose of the present study is to compare the effects of ranibizumab
and bevacizumab in endothelial cell growth, apoptosis, migration and in vitro capilary-like
tubule formation.
METHODS: Human Umbilical Vein Endothelial Cell (HUVEC) cultures were incubated
with different concentrations of ranibizumab or bevacizumab within the doses used in the
clinic, or their excipients. HUVEC viability (by MTT), proliferation (by BrdU
immunoassay), apoptosis (by TUNEL assay) and migration (using double-chamber assays)
were performed. Evaluation of tubule-like structures formation was performed on matrigelcoated
plaques incubated with ranibizumab, bevacizumab or their excipients.
RESULTS: Neither bevacizumab nor ranibizumab presented cytotoxic effects, as evaluated
by MTT assay. HUVEC proliferation was significantly reduced by the two agents, as
compared to excipient-treated controls. Incubation with bevacizumab at five different
concentrations led to increase apoptosis. Ranibizumab treatment resulted in increased
apoptosis in the two higher concentrations tested. Cell migration was only affected by
higher concentrations of both agents. Cell assembly into capillary-like structures was
effectively downregulated by incubation with bevacizumab at the clinically used dose,
whereas ranibizumab treatment resulted in decreased cord formation, although not
reaching statistical significance.
CONCLUSIONS: This study demonstrated that clinical doses of bevacizumab and
ranibizumab are able to prevent several steps of the angiogenic process in a distinct
manner. Statistical analyses are being performed in order to elucidate the precise effects of
each of the agents examined.
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