Abstract
Purpose: :
The purpose of this study is to evaluate the spatial distribution of blood vessels in the LHBETATAG mouse model of retinoblastoma. We propose to model tumor vascular development and to correlate this model with proposed impacts on antiangiogenic therapies for the treatment of retinoblastoma.
Methods: :
The study protocol was approved by the University of Miami, IACUC. All experiments were conducted in accordance with the ARVO Statement for the Use of Animals in Ophthalmic and Vision Research. Vessel heterogeneity in retinal tumors from LHBETATAG mice of advanced disease 12 and 16 weeks of age (n=8 per group) were assessed by immunofluorescence. Total blood vessels were detected by immunostaining with lectin from bandeira simplicifolia, neovessels with CD105 (endoglin) and pericyte-committed mature vessels with α-smooth muscle actin.
Results: :
As previously reported, tumor vasculature is evenly distributed throughout the tumor area. The degree of vessel maturation, however, was heterogeneous among different tumor areas. Tumors had higher mean neovessel densities than mature vasculature at tumor apex (p=0.03) and tumor margins (p=0.04). On the other hand, differences between neovessel and mature vessel densities were not significant (p=0.1). These results suggest that angiogenic activity is mainly present at leading edges of tumors and vessel maturation ensues in areas closest to the tumor base.
Keywords: retina • tumors • immunohistochemistry