An Endothelial-Integrated 3D Compartmentalized Osteochondral Platform for Modeling Vascular-Osteochondral Interactions

Osteochondral tissues consist of cartilage, subchondral bone, and vascular networks that collectively regulate tissue homeostasis and regeneration. However, current in vitro osteochondral models remain limited in their ability to recapitulate physiologically relevant vascularized microenvironments and multicellular tissue interactions. In this study, we developed an endothelial-integrated three-dimensional (3D) microfluidic osteochondral platform incorporating human adipose-derived stem cell (hADSC)-derived spheroids and endothelial cells for osteochondral modeling and drug response evaluation.

An endothelial-integrated 3D microfluidic osteochondral platform was developed using hADSC-derived chondrogenic and osteogenic spheroids together with endothelial cells. Microenvironment-structured spheroid (MSS) culture, co-culture medium optimization, and pre-vascularized structures (PVS) were employed to investigate vascular-osteogenic interactions and osteochondral impairment under dexamethasone (Dex)-induced stress conditions.

The platform enabled the spatial organization of chondrogenic spheroids, osteogenic spheroids, and endothelial cells within distinct microfluidic compartments, establishing a vascularized osteochondral-like microenvironment. MSS culture significantly promoted osteogenic differentiation while maintaining long-term viability. Optimized co-culture conditions supported both endothelial and osteogenic functions, whereas PVS further enhanced osteogenic differentiation. Under Dex-induced stress conditions, iloprost treatment partially restored vascular, osteogenic, and chondrogenic markers.

This study presents an endothelial-integrated 3D microfluidic osteochondral platform capable of reproducing vascular-osteogenic interactions and modeling osteochondral impairment under Dex-induced stress conditions. These findings highlight the platform's potential as a physiologically relevant in vitro model for osteochondral tissue engineering and therapeutic evaluation.