Development and disease modelling in engineered vascular tissues

Why did we fund this project?

This joint award with the British Heart Foundation (BHF) aims to establish a ‘disease-in-a-dish' model to replace some studies of cardiac vascular disease in mice.

Changes in the extracellular matrix (ECM, a mix of proteins and other molecules secreted by cells) in heart arteries underpins vascular disease. Excessive ECM leads to formation of plaques which clog arteries, termed atherosclerosis, and stiffening of the arterial wall seen in vascular aging. Simple cell cultures do not allow the ECM to accumulate and in vivo studies, predominantly in mice, are considered the current ‘gold standard’. In vivo experiments may include high fat diets to induce atherosclerosis, or angiotensin injection or vein grating to study the effects of high blood pressure. The student, with Professor Manuel Mayer, aims to establish engineered vascular tissues (EVTs) as a ‘disease-in-a-dish' model of pathological ECM remodelling. EVTs consist of human heart cells in a 3D matrix, which retains ECM allowing vascular disease progression to be studied in vitro.

Overview:
Engineered cardiac tissues formed from induced pluripotent stem cells are increasingly replacing animal models for initial screening of cardiotoxicity and drug effects on cardiac contractility, but no such model exists for the vasculature. Here, we aim to establish, validate, and demonstrate the utility of engineered vascular tissues (EVTs)¹ to study extracellular matrix (ECM) remodelling, lipoprotein retention and calcification in the vasculature that can replace in vivo models of atherosclerosis and vascular stiffness.

The 3Rs case:
Atherosclerosis is a chronic inflammatory disorder caused by retention of lipoproteins by the ECM in the arterial wall. Similarly, arterial stiffening is a hallmark of vascular ageing and induced by alterations in the vascular ECM leading to progressive calcification. Genetic mouse models are a mainstay of vascular research, but could be partially replaced by murine and preferably human-derived EVTs. Experimental models to study this pathological matrix remodelling have, for the most part, remained in vivo because the ECM secretion by vascular SMCs in 2D cell cultures preclude controlled studies of 3D vascular ECM remodelling. Here, we propose to develop a new experimental tool that would allow for some murine studies of cardiovascular-associated pathological ECM remodelling to move into human EVT models.

Experimental approach:
Our approach relies on a fibrin-based 3D culture of primary human vascular SMCs to allow for the study of ECM remodelling in vitro. This would replace the need for many mouse models. We will encapsulate human primary vascular SMCs within our established fibrin-derived 3D matrices and expose them to conditions, i.e. high calcium phosphate or excess of lipoprotens, that prompt vascular SMCs to adopt a disease-like phenotypes ("disease-in-a-dish" models). To validate our model, we will then use a proteomics-based approach^2,3 to demonstrate that our "disease-in-a-dish" model can confirm known and identify novel matrix regulators that can potentially be targeted therapeutically to treat vascular diseases. We will also perform proteomics comparisons between human and murine EVTs to promote uptake of human EVTs by highlighting the similarities and differences in ECM remodelling between human and murine aortic SMCs.

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