A Modular Strategy to Engineer Complex Tissues and Organs.

Area of Science:

• Tissue Engineering
• Biomaterials Science
• Regenerative Medicine

Background:

• Current treatments for large tracheal defects lack suitable long-term synthetic or biologic materials.
• A successful tracheal replacement requires radial rigidity, an immunoprotective epithelium, and vascular integration.

Purpose of the Study:

• To develop a novel biomaterial strategy for engineering complex, multi-tissue tracheal constructs.
• To assess the potential of microparticle-mediated cell self-assembly for creating functional tracheal replacements.

Main Methods:

• Biopolymer microspheres delivered chondrogenic growth factors to human mesenchymal stem cells (hMSCs) for cartilage ring formation.
• Composite tissues were created by combining hMSC-derived cartilage with human epithelial cells and prevascularized rings (endothelial cells and hMSCs).
• Tri-tissue constructs were formed and implanted subcutaneously in mice to evaluate vascular integration.

Main Results:

• Self-assembled cartilage rings and tubes exhibited tunable properties and mechanical strength for airway collapse prevention.
• Epithelialized cartilage sheets and prevascular-cartilage composite tubes were successfully fabricated.
• Implanted prevascular-cartilage tubes demonstrated anastomosis with host vasculature, indicating successful perfusion.

Conclusions:

• The microparticle-cell self-assembly strategy is a promising approach for engineering complex multi-tissue constructs.
• This method offers a viable pathway for developing functional composite tracheas to address large tracheal defects.