Development and Validation of a Sponge Model for Quantitative Studies on Angiogenesis

Abstract

The assays for angiogenesis in current use include the corneal micropocket technique (Gimbrone et al., 1974; Leibovich et al., 1987), chick embryo chorioallantoic membrane (Auerbach et al., 1974; Crum et al., 1985), the hamster cheek pouch (Greenblatt & Shubik,1968; Schrieber et al., 1986), and rat dorsal air sac (Folkman et al., 1971; Ingber et al., 1990). The development of these methods in the 1970s was instrumental in the discovery, purification and biochemical characterisation of angiogenic factors and inhibitors. However, these models, with the exception of the corneal assay, are only qualitative or semi-quantitative. Thus Vallee et al. (1985) concluded that “none of the procedures available for studying angiogenesis is ideal and that the design and verification of specific and reproducible methodology remains an imperative of the highest priority”. In the last five years, several new models have been developed, e.g. subcutaneous implantation of plastic chambers (Dvorak et al., 1987) or porous polytetrafluoroethylene tubes (Sprugel et al., 1987). In addition, techniques involving the subcutaneous implantation of sterile sponges into experimental animals have become popular (Davidson et al., 1985; Fajardo et al., 1988; Kusaka et al., 1991).