Inflammation in tissue engineering: The Janus between engraftment and rejection

Area of Science:

• Biomaterials Science
• Immunology
• Regenerative Medicine

Background:

• Tissue engineering (TE) utilizes scaffold implants for tissue and organ regeneration, supporting seeded or recruited cells.
• TE implants provoke host immune responses, potentially causing engraftment issues or rejection.
• The immune system also positively influences stem cell recruitment and differentiation, crucial for tissue healing.

Purpose of the Study:

• To review strategies for modulating immune responses in TE to improve implant success.
• To highlight the critical role of macrophage plasticity in TE outcomes.
• To emphasize the three-way interaction between scaffolds, immune cells, and stem cells.

Main Methods:

• Literature review of current and potential strategies for inflammation modulation in TE.
• Analysis of the interplay between scaffold design, immune response, and stem cell behavior.
• Discussion of macrophage plasticity's role in orchestrating immune responses.

Main Results:

• Immune responses to TE implants present both challenges (rejection) and opportunities (stem cell recruitment).
• Macrophage plasticity is a central mechanism influencing TE outcomes.
• Scaffold design and functionalization can direct inflammation towards regeneration and vascularization.

Conclusions:

• Modulating the immune response, rather than suppressing it, is a promising strategy for TE success.
• The quality, not quantity, of inflammation is critical for successful engraftment and regeneration.
• Optimizing the scaffold-immune-stem cell interaction is essential for advancing TE therapies.