An Improved In Vivo Angiogenesis Model of Chicken Chorioallantoic Membranes in Surrogate Shells Revealed the Pro-angiogenesis Effects of Chylomicrons

Chicken chorioallantoic membrane (CAM) models have been applied as an affordable and efficient angiogenesis model for many years in relevant areas such as cancer angiogenesis and cardiovascular sciences. However, this model has intrinsic weaknesses such as the difficulty of operation and the limited size of the viewing windows. Efforts of trying to improve this model, such as transferring the embryos into petri dishes, has led to compromised survival rate of the embryos. In this study we improve the workflow by using surrogate egg shells. The images obtained from the viewing windows of the surrogate shells allow us to apply automated image analysis. This CAM model in surrogate shells combined with automated image analysis significantly decreases the labour whilst also increasing the data quality, when compared to traditional CAM models. Furthermore, to demonstrate the potential of our model, we have investigated the effects of a range of chylomicrons, extracted from murine and human samples, using the improved CAM model, to seek clues to elucidate the controversial roles of high level chylomicrons (CMs) in hypertriglyceridaemia (HTG) on atherosclerosis. We show that both native and modified chylomicrons (CMs) promote in vitro and in vivo angiogenesis. As angiogenesis is a risk factor in atherosclerosis our results provide a new mechanism for the effect of hypertriglyceridaemia (HTG) on atherosclerosis development. In summary, we demonstrate an improved CAM model aided by automated image analysis, we demonstrate the potential of this model by demonstrating interfered angiogenesis caused by HTG and discuss the impact this could potentially cause other pathological processes, such as atherosclerosis or carcinogenesis. Furthermore, the significantly low cost of CAM models compared with traditional murine models for cardiovascular research will have potential 3Rs (replacement, reduction and refinement) significance for the research communities, especially for laboratories with limited budgets or regulatory restrictions.