Sonic Hedgehog-activated engineered blood vessels enhance bone tissue formation.

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Developmental Biology

Background:

• Large bone defects pose significant challenges in regenerative medicine.
• Current bone tissue engineering methods struggle with inadequate vascularization and stepwise differentiation.
• Mimicking natural endochondral bone repair is crucial for effective treatment.

Purpose of the Study:

• To investigate the role of Sonic Hedgehog (Shh) in inducing vascularization within artificial tissues.
• To enhance the in vivo perfusion and bone formation of engineered tissues.
• To develop novel strategies for treating large bone defects by recapitulating natural bone repair processes.

Main Methods:

• Utilized the morphogen Sonic Hedgehog (Shh) to induce in vitro capillary network formation in artificial tissues.
• Assessed the effects of endogenous and exogenous Shh on angiogenic gene expression and vascular lumen development.
• Evaluated the in vivo performance of engineered tissues upon implantation, focusing on perfusion and bone formation.

Main Results:

• Shh was shown to regulate angiogenic genes and promote vascular lumen formation in vitro.
• Exogenous Shh significantly improved in vitro vascular development, including lumen formation, size, and distribution.
• Implanted tissues exhibited enhanced in vivo perfusion and contributed to de novo mature bone formation.
• Engineered tissues underwent intramembranous and endochondral ossification, forming a trabecular-like bone organ with bone-marrow-like cavities.

Conclusions:

• Sonic Hedgehog (Shh) is a key regulator of vascular development in engineered tissues.
• In vitro vascularization induced by Shh improves in vivo tissue perfusion and bone regeneration.
• This approach offers a promising strategy for treating large bone defects by closely mimicking natural endochondral bone repair.