A critical analysis of current in vitro and in vivo angiogenesis assays

Abstract

Summary The study of angiogenesis has grown exponentially over the past 40 years with the recognition that angiogenesis is essential for numerous pathologies and, more recently, with the advent of successful drugs to inhibit angiogenesis in tumours. The main problem with angiogenesis research remains the choice of appropriate assays to evaluate the efficacy of potential new drugs and to identify potential targets within the angiogenic process. This selection is made more complex by the recognition that heterogeneity occurs, not only within the endothelial cells themselves, but also within the specific microenvironment to be studied. Thus, it is essential to choose the assay conditions and cell types that most closely resemble the angiogenic disease being studied. This is especially important when aiming to translate data from in vitro to in vivo and from preclinical to the clinic. Here we critically review and highlight recent advances in the principle assays in common use including those for endothelial cell proliferation, migration, differentiation and co‐culture with fibroblasts and mural cells in vitro, vessel outgrowth from organ cultures and in vivo assays such as chick chorioallantoic membrane (CAM), zebrafish, sponge implantation, corneal, dorsal air sac, chamber and tumour angiogenesis models. Finally, we briefly discuss the direction likely to be taken in future studies, which include the use of increasingly sophisticated imaging analysis systems for data acquisition.

Effects of hypergravity on the angiogenic potential of endothelial cells

“…Indeed, alterations in the cytoskeleton were evaluated, as this cellular structure is a major responder to mechanical forces [17], including alterations in gravity. Moreover, the functionality of ECs was assessed in a threedimensional matrigel matrix, which constitutes a suitable environment for EC assembly into capillary-like structures [18]. In addition, different times of exposure (4 and 16 h) and g levels (3 and 10g) were studied.…”

Vascular-targeted agents for the treatment of angiosarcoma

“…Cell migration may be assessed in vitro by several different methods [163]. The scratch assay requires a monolayer of cells to which a 'wound' (scratch) is applied.…”

G 2 /M cell cycle arrest on HT-29 cancer cells and toxicity assessment of triphenylphosphanegold(I) carbonimidothioates, Ph 3 PAu[SC(OR) = NPh], R = Me, Et, and iPr, during zebrafish development

“…The use of zebrafish (Danio rerio) has emerged as a powerful model system to monitor angiogenesis in vivo [15][16][17]. Zebrafish have been used as a model organism for research purposes for more than 20 years and therefore handling methods, optimum breeding techniques, husbandry, and maintenance are well established [18].…”

“…Recent research has shown that most of the genes found in humans have at least one zebrafish orthologue [19]. The above ensures zebrafish as being highly useful for the study of complex biological processes such as cell 6 senescence and apoptosis, aging, cardiovascular system development, and drug toxicity response [15][16][17][18][19][20][21]. There are a few special characteristics of zebrafish that are worth highlighting.…”