Endothelial microvascular networks affect gene-expression profiles and osteogenic potential of tissue-engineered...

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Regenerative Medicine

Background:

• Vascularization is a critical factor limiting the size of cell/scaffold constructs in tissue engineering.
• Understanding the interplay between endothelial cells (ECs) and mesenchymal stem cells (MSCs) is crucial for developing functional tissue constructs.

Purpose of the Study:

• To investigate the in vitro angiogenic and osteogenic gene-expression profiles of cocultured ECs and MSCs within a dynamic 3D environment.
• To evaluate the in vivo differentiation and osteogenic potential of these constructs after implantation.

Main Methods:

• MSCs and ECs were cultured in poly(L-lactide-co-1,5-dioxepan-2-one) (poly(LLA-co-DXO)) scaffolds for 1 week to form 3D microvascular networks.
• Constructs were implanted in a murine model for ectopic bone formation.
• Gene expression for angiogenesis and osteogenesis, cell proliferation (ki67), perivascular differentiation (α-smooth muscle actin), and osteogenesis markers (ALP, Alizarin Red, HE, Masson trichrome) were analyzed.

Main Results:

• Functional endothelial microvascular networks were successfully generated in vitro and sustained after in vivo implantation.
• Co-culturing ECs with MSCs modulated both angiogenic and osteogenic gene expression profiles.
• MSCs demonstrated the ability to support functional blood vessels as perivascular cells, and alkaline phosphatase (ALP) expression was upregulated in the presence of microvascular networks.

Conclusions:

• Poly(LLA-co-DXO) scaffolds can be effectively prevascularized using ECs and MSCs.
• While ectopic bone formation requires an osteoinductive environment, the inclusion of ECs with MSCs enhances the osteogenic potential of tissue-engineered constructs.