CAM Model: Intriguing Natural Bioreactor for Sustainable Research and Reliable/Versatile Testing

Abstract

We are witnessing the revival of the CAM model, which has already used been in the past by several researchers studying angiogenesis and anti-cancer drugs and now offers a refined model to fill, in the translational meaning, the gap between in vitro and in vivo studies. It can be used for a wide range of purposes, from testing cytotoxicity, pharmacokinetics, tumorigenesis, and invasion to the action mechanisms of molecules and validation of new materials from tissue engineering research. The CAM model is easy to use, with a fast outcome, and makes experimental research more sustainable since it allows us to replace, reduce, and refine pre-clinical experimentation ("3Rs" rules). This review aims to highlight some unique potential that the CAM-assay presents; in particular, the authors intend to use the CAM model in the future to verify, in a microenvironment comparable to in vivo conditions, albeit simplified, the angiogenic ability of functionalized 3D constructs to be used in regenerative medicine strategies in the recovery of skeletal injuries of critical size (CSD) that do not repair spontaneously. For this purpose, organotypic cultures will be planned on several CAMs set up in temporal sequences, and a sort of organ model for assessing CSD will be utilized in the CAM bioreactor rather than in vivo.

Keywords: angiogenesis; chorioallantoic membrane (CAM); engineered 3D scaffold; organotypic culture.

Figure 1

(A) Observation of a chicken embryo at ED3 (scale bar = 1 mm). (B) Chicken embryo at ED3 in an ex ovo experiment (scale bar = 0.5 cm). (C) Hematoxylin and eosin staining of a chicken CAM at ED13; image taken using a Nikon microscope at 10× magnification. V: a major CAM blood vessel; arrow-head: sub-chorion capillaries.