Scalable microphysiological system to model three-dimensional blood vessels.

Mees N S De Graaf,Amy Cochrane,Albert Van Den Berg,Wesley Buijsman,Andries D Van Der Meer,Francijna E Van Den Hil,Valeria V Orlova,Christine L Mummery

doi:10.1063/1.5090986

Mees N S De Graaf, Amy Cochrane + Show 6 more

Open Access

https://doi.org/10.1063/1.5090986

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Abstract

Blood vessel models are increasingly recognized to have value in understanding disease and drug discovery. However, continued improvements are required to more accurately reflect human vessel physiology. Realistic three-dimensional (3D) in vitro cultures of human vascular cells inside microfluidic chips, or vessels-on-chips (VoC), could contribute to this since they can recapitulate aspects of the in vivo microenvironment by including mechanical stimuli such as shear stress. Here, we used human induced pluripotent stem cells as a source of endothelial cells (hiPSC-ECs), in combination with a technique called viscous finger patterning (VFP) toward this goal. We optimized VFP to create hollow structures in collagen I extracellular-matrix inside microfluidic chips. The lumen formation success rate was over 90% and the resulting cellularized lumens had a consistent diameter over their full length, averaging 336 ± 15 μm. Importantly, hiPSC-ECs cultured in these 3D microphysiological systems formed stable and viable vascular structures within 48 h. Furthermore, this system could support coculture of hiPSC-ECs with primary human brain vascular pericytes, demonstrating their ability to accommodate biologically relevant combinations of multiple vascular cell types. Our protocol for VFP is more robust than previously published methods with respect to success rates and reproducibility of the diameter between- and within channels. This, in combination with the ease of preparation, makes hiPSC-EC based VoC a low-cost platform for future studies in personalized disease modeling.

Highlights

Blood vessels are lined with endothelial cells (ECs) and surrounded by mural cells called smooth muscle cells or pericytes
We have developed methods which support differentiation of ECs from Human induced pluripotent stem cells (hiPSCs) under defined culture conditions and have shown that these cells are functional in a multiplicity of assays in vivo and in vitro.[23,24] hiPSCs can be derived from patients with specific disease genotypes or healthy control individuals with minimally invasive tissue collection.[25]
It proved to be rapidly scalable and applicable to vascular structures consisting of hiPSC-derived vascular cells

Summary

Introduction

Blood vessels are lined with endothelial cells (ECs) and surrounded by mural cells called smooth muscle cells or pericytes. The interaction between mural cells and ECs provides many vessels with stability and abnormal interactions can lead to conditions such as hemorrhage, vascular dementia, and chronic infection.[1,2,3] EC and mural cell interaction influences the selectivity of the barrier, which determines whether compounds can enter or are excluded from an organ, and they are important factors in drug efficacy and tissue selectivity.[4,5] Studying interaction between ECs and mural cells can be complex; for instance, combining threedimensional (3D) geometry and controlled fluid flow is challenging in vitro. Wall shear stress is an important determinant of the vascular function.[9] Its magnitude can be estimated by assuming that blood vessels are straight cylinders with a constant flow rate and viscosity, using the following equation:[8,10] s

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