Development and characterization of a novel endothelialized in vitro model of human atherothrombosis

Cardiovascular disease is the leading cause of death globally, responsible for 17.7 million deaths a year, 80% of which are caused by heart attacks and strokes. These arise when atherosclerotic plaques, in coronary or carotid arteries rupture or erode releasing tissue factor and exposing components of the blood vessel wall, which trigger thrombosis (atherothrombosis). The development of atherothrombosis is a complex and highly regulated process involving the blood vessel wall, platelets, endothelial cells, and plasma proteins. To investigate the mechanisms that lead to atherothrombosis, and develop more effective, antithrombotic treatments, appropriate experimental models are crucial.

Currently thousands of animals are used annually in a variety of in vivo thrombosis models. Standardization of these models between research groups is challenging and results are often variable, requiring large numbers of animals to achieve statistically relevant results. While these studies have significantly increased our understanding of platelet function in a damaged blood vessel, they do not accurately represent human disease. In addition to species differences, current in vivo models lack the endothelial dysfunction, and altered blood vessel wall composition associated with cardiovascular disease. It is therefore crucial from both an ethical and scientific perspective that advances are made to reduce animal usage and provide more clinically relevant models in thrombosis research. The aim of this study is to develop and validate an in vitro model of human atherothrombosis, which reflects the in vivo environment following plaque rupture or erosion and provides an alternative to animal thrombosis models.

In this study, we will develop two composites, which reflect the distinct components of the blood vessel wall, exposed following rupture or erosion of an atherosclerotic plaque. Endothelial cells will be cultured on these matrix proteins in fluidic chambers, and experimental damage will be induced to trigger thrombosis in an environment similar to that observed in human atherothrombosis. The model will use human blood, human endothelial cells and haemodynamic forces relevant to those in human coronary arteries to offer a more physiologically relevant platform to investigate human atherothrombosis and test novel antithrombotic treatments.

Development of the model will be optimised at each stage to ensure the most cost-effective approach without compromising validity. Data obtained using the model will be validated against published data from equivalent in vivo experiments and against human histopathology studies characterizing atherothrombosis composition on ruptured and eroded lesions. We will also evaluate the cost and resources required to perform experiments using our model compared to equivalent in vivo experiments. The delivery of a simple and cost-effective endothelialized in vitro model of human atherothrombosis, will facilitate a more ethical and translational approach for testing novel antithrombotic drugs, with the potential for high uptake and a significant reduction in the number of animals used in cardiovascular research.

This Studentship was co-awarded with the British Heart Foundation (BHF).

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