Enhanced Bone Formation in Segmental Defect Healing Using 3D Printed Scaffolds Containing Bone Marrow Stromal Cells...

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Orthopedic Surgery

Background:

• Nonunion bone healing stems from critical-size defects hindering fracture repair.
• Developing novel therapies for complex bone injuries requires advanced models beyond simple murine fractures.
• Fracture callus development is a complex process necessitating targeted therapeutic strategies.

Purpose of the Study:

• To investigate a 3D-printed scaffold for sequential small molecule delivery to enhance nonunion bone healing.
• To augment chondrogenesis and angiogenesis during critical stages of fracture repair.
• To evaluate the efficacy of combined bone marrow stromal cells (BMSCs) and targeted therapies.

Main Methods:

• A 3D-printed scaffold with layered release of sonic hedgehog (SHH) agonist and prolyl-hydroxylase domain (PHD)2 inhibitor.
• Sequential delivery of SHH agonist for chondrogenesis and PHD2 inhibitor for angiogenesis.
• Incorporation of BMSCs to enhance cell substrate for therapeutic delivery in a murine segmental defect model.

Main Results:

• Increased expression of PTCH1 and HIF1α in treated mice, indicating activation of hedgehog and hypoxia pathways.
• MicroCT and histological analyses demonstrated enhanced bone formation in the fracture callus of treated mice.
• The scaffold facilitated new bone formation, showing feasibility of the therapeutic approach.

Conclusions:

• The developed fibrin gel/β-TCP scaffolds with BMSCs and sequential small molecules show feasibility for promoting bone formation in segmental defects.
• Further optimization is needed to achieve complete bony union in large defects.
• This approach represents a promising strategy for treating challenging bone injuries.