The Mouse Aorta Model: Influence of Genetic Background and Aging on bFGF- and VEGF-Induced Angiogenic Sprouting

Abstract

Angiogenesis can be studied ex vivo by culturing rat or mouse aortic rings in collagen gels. Unlike rat aorta explants, unstimulated mouse aortic rings were unable to spontaneously produce an angiogenic response under serum-free conditions. They, however, responded to bFGF and VEGF, generating networks of branching neovessels. Aortic rings from GFP-Tie2-transgenic mice generated GFP-labeled neovessels that could be easily identified by their distinctly green fluorescence. Aortic rings from 1- to 2-month-old mice produced microvessels faster, more uniformly and in greater number than aortic rings from 6- to 10-month-old mice, particularly in VEGF-treated cultures. Aortic rings from 129/SVJ mice were capable of a much stronger and sustained angiogenic response to bFGF than those of C57BL/6 or BALB/c mice, which were in turn more angiogenic than aortic rings from FVB mice. The same strains of mice responded differently to VEGF, as C57BL/6 mouse aortic rings produced more microvessels than those of BALB/c, FVB, and 129/SVJ mice, which were capable of only a limited response. The significant impact that aging and genetic background have on mouse aortic angiogenesis should be taken into account when the aortic-ring assay is used to evaluate function of genes that have been deleted or overexpressed in genetically modified mice.

Modeling human tumor angiogenesis in a three-dimensional culture system

“…[3][4][5][12][13][14][15]26 In this study, we describe a reproducible system for investigating the angiogenic cascade by controlling experimental variables and precisely quantifying angiogenic outgrowth. We developed a human angiogenesis model, in which umbilical artery rings embedded in BME produced capillarylike structures, recapitulating different steps of angiogenesis, including EC sprouting, migration, and differentiation into capillaries.…”

“…Adaptations of this assay allow direct monitoring of the angiogenic process and the study of endothelial tip cell dynamics. [8][9][10][11] However, rat and mAR models display certain disadvantages: a high age-and strain-dependent variability of assays, 12 as well as variations owing to the region of the explanted aorta 13 ; autonomous angiogenic outgrowth, limiting studies on proangiogenic factors 14 ; the necessity to sacrifice animals; and the failure to detect species-specific antiangiogenic compounds in preclinical screening assays. 15 In this study, we developed an ex vivo three-dimensional (3D) assay of sprouting angiogenesis with arterial explants from human umbilical cords.…”

In vitro assays of angiogenesis for assessment of angiogenic and anti-angiogenic agents

“…Angiogenesis assays can be conducted using endothelial cells with specific characteristics or labels; for example, aortas from mice whose endothelial cells express green-fluorescent protein can be used to facilitate visualization of vessel outgrowth (Zhu et al, 2003). Angiogenic outgrowth occurs over a shorter time period with the mouse aortic rings (Masson et al, 2002), and both angiogenic and anti-angiogenic factors can be assessed (e.g.…”

“…Variability in the handling of the rings and the amount of adventitia remaining on the vessel can influence vessel outgrowth within an experiment. Use of rings from different aortas and, particularly with mice, different ages and strains of animals (Zhu et al, 2003) can lead to variability in angiogenic responses. Vessel outgrowth usually occurs in three dimensions, complicating photography and quantification.…”

Impact of host ageing on the metastatic phenotype

“…Moreover, the vascular system (the main conduit of metastasis) undergoes significant changes over the life time (Lusis 2000). Aging also affects bone marrow function (Rauscher et al 2003), the inflammatory system and mechanisms of angiogenesis (Pili et al 1994;Rivard et al 1999;Zhu et al 2003). We have previously documented impaired growth, neovascularisation and therapeutic responses of experimental tumors in aged mice relative to their young (standard) experimental counterparts, especially in the context of age-related comorbidities, such as atherosclerosis (Klement et al 2007).…”