Effect of Serum on Smooth Muscle Cell Phenotype in 3D Tissue-Engineered Microvessels.

Smooth muscle cells (SMCs) are a critical cellular component of the tunica media of blood vessels in arteries and arterioles. Despite their importance, the development of in vitro arteriole models with diameters <200 µm remains challenging, largely due to difficulties in culturing SMCs at these length scales. In particular, uncontrolled SMC overproliferation can lead to microvessel vessel narrowing and occlusion. Here, we report a 3D microfluidic-based tissue-engineered model with human brain SMCs forming a microvessel approximately 150 μm in diameter within a collagen I hydrogel. Using this platform, we demonstrate that serum-free culture conditions are essential to prevent SMC overproliferation and maintain vessel patency. In addition, SMCs cultured in serum-free and serum-supplemented conditions exhibit distinct functional phenotypes, consistent with previous studies in 2D culture. These results provide a strategy for fabrication of tissue-engineered arteriole models.