Key parameters for designing robust 2D and 3D spheroid models for in vitro atherosclerosis research

Atherosclerosis is a chronic, systemic, inflammatory disease associated with the build-up of fatty deposits ("plaques") in the arteries. A major global health burden, severe atherosclerosis progresses to ischemic heart disease, an underlying condition which can exacerbate the occurrence of fatal events such as heart attack and stroke. Over the past two decades, the use of in vitro models to study atherosclerotic phenomena has increased, with the goal of complementing clinical research for drug and therapy development. In particular, 2D co-culture models, and in the last decade, 3D spheroid models have been developed to improve our understanding of the atherosclerotic disease mechanism. However, the existing literature lacks information on the relevant parameters which should be considered prior and during the design of these models to promote model robustness and enhance their biomimetic capacities. This review provides an overview of such key parameters, as well as future perspectives on how existing limitations in the field of cell-based in vitro model design can be improved. It is expected that by carefully considering these parameters, researchers will be better equipped with the required knowledge to develop biomedically and clinically relevant in vitro models.