Embedded 3D-Coaxial Bioprinting of Stenotic Brain Vessels with a Mechanically Enhanced Extracellular Matrix Bioink for Investigating Hemodynamic Force-Induced Endothelial Responses

Stenotic regions in cerebral vessels are implicated in diseases such as atherosclerosis, where shear-responsive endothelial function is critical to disease progression. However, studying flow-induced inflammation remains challenging due to the complexity of in vivo conditions, highlighting the need for a well-engineered in vitro model. A physiologically relevant in vitro model of stenotic brain vessels using 3D-coaxial bioprinting and a mechanically enhanced extracellular matrix (ECM) bioink is developed to investigate flow-induced endothelial inflammation. The hybrid bioink, composed of vascular decellularized ECM, collagen, and alginate, exhibits an approximately 65-fold increase in dynamic modulus, enabling stable formation of perfusable structures. Printing parameter optimization facilitates precise fabrication of stenotic vessels with a luminal diameter of 250–500 µm. Computational fluid dynamics simulations under an inlet flow rate of 3 mL min⁻¹ predict disturbed fluid flow in stenotic regions. The bioprinted vessels exhibit continuous endothelial coverage, expression of junction proteins (CD31, ZO-1, and VE-cadherin), and size-dependent permeability, indicating a mature vascular barrier formation. Under disturbed flow conditions, ICAM-1 (approximately 2.2-fold) and VCAM-1 (approximately 1.5-fold) are upregulated, confirming the hemodynamic stress-induced inflammation. These findings highlight the potential of 3D bioprinting for modeling cerebrovascular disease in vitro and paving the way for future therapeutic innovation.