Construction and Applicability Scenarios of 3D Neurovascular Unit Models In Vitro

The neurovascular unit (NVU) is composed of a diverse array of cells and an extracellular matrix (ECM). Neural cells and blood vessels are intricately interconnected, forming a cohesive whole. Specific cellular components and structures within the NVU play an indispensable role in maintaining homeostasis of the central nervous system (CNS). With the advancement and maturation of cell co-culture technology, various three-dimensional (3D) NVU models continue to emerge, offering a more objective and comprehensive perspective for in vitro studies of CNS diseases. Specifically, these 3D NVU models include Transwell Chamber models, gel-polydimethylsiloxane (PDMS)-based 3D models, self-assembled NVU models and microfluidic NVU models, which reconstruct the complex NVU architecture to varying degrees. This review systematically summarizes multiple 3D construction strategies for in vitro NVU to overcome the limitations of conventional cellular tests or animal experiments, highlights the critical roles of biomimetic gel in recapitulating native cell-gel crosstalk, comparatively analyzes four major 3D NVU technical routes in terms of cellular composition, vascular morphology, barrier performance, and reproducibility, categorizes application scenarios of 3D NVU platforms oriented to practical research demands, including oxygen-glucose deprivation/reoxygenation (OGD/R) injury modeling, blood-brain barrier (BBB) permeability assay, CNS drug penetration screening, neuroinflammation and neurotoxicity evaluation, proposes practical principles for model selection under different experimental purposes, and concludes with current bottlenecks, including imperfect vascular network maturation and lack of unified evaluation criteria, together with future perspectives for standardized 3D NVU in vitro. By comparing the advantages and limitations of these approaches, we aim to clarify their optimal applicability for investigating specific pathological mechanisms and screening potential therapeutics.