Biomaterials delivery strategies to repair spinal cord injury by modulating macrophage phenotypes

Journal of Tissue Engineering, 2022 · DOI: 10.1177/20417314221143059 · Published: November 17, 2022

Simple Explanation

Spinal cord injury (SCI) can cause physical, mental, and financial strain, and recovery is complicated by inflammation. Macrophages, which are immune cells, have dual roles in SCI, with M1 macrophages exacerbating injury through inflammatory factors and M2 macrophages promoting repair by reducing inflammation and neuronal death. Biomaterials are being explored as a way to guide macrophages toward the M2 phenotype, promoting a healing environment in the injured spinal cord. This review discusses how biomaterials can be used to modulate macrophage behavior to improve SCI recovery. Biomaterials can be designed to deliver specific signals or drugs to the injury site, influencing the behavior of macrophages and promoting tissue repair. This approach holds promise for developing more effective treatments for SCI.

Study Duration

Not specified

Participants

Not specified

Evidence Level

Review

Key Findings

1
M1 macrophages exacerbate SCI by secreting inflammatory factors, while M2 macrophages promote tissue repair by releasing anti-inflammatory cytokines and neurotrophic factors.
2
Biomaterials can be engineered to modulate macrophage phenotypes in the SCI microenvironment, promoting a shift from the pro-inflammatory M1 phenotype to the anti-inflammatory M2 phenotype.
3
Various biomaterial-based strategies, including nanoparticles, hydrogels, and scaffolds, have shown promise in preclinical studies for promoting SCI repair by modulating macrophage polarization.

Research Summary

Spinal cord injury leads to significant physical, psychological, and financial burdens, and current treatments often fail to fully repair damaged nerve cells. Inflammation plays a complex role, with early inflammation helping to clear debris but prolonged inflammation hindering recovery. Macrophages exhibit paradoxical effects in SCI, with M1 macrophages exacerbating injury through inflammatory factors and M2 macrophages promoting repair. Modulating macrophage phenotypes is a promising therapeutic strategy. Biomaterials are being developed as delivery vehicles to modulate macrophage phenotypes in the SCI microenvironment. Nanoparticles, gels, and scaffolds can deliver drugs, growth factors, and other molecules to promote M2 polarization and axon regeneration.

Practical Implications

Targeted Drug Delivery

Biomaterials can be designed to specifically deliver drugs and signaling molecules to the injury site, maximizing therapeutic efficacy and minimizing side effects.

Microenvironment Modulation

Biomaterials can create a pro-regenerative microenvironment by promoting M2 macrophage polarization, reducing inflammation, and supporting axon regeneration.

Stem Cell Therapy Enhancement

Biomaterials can improve the delivery and survival of stem cells at the injury site, enhancing their ability to secrete growth factors and promote tissue repair.

Study Limitations

1
Current research is primarily in animal models, and clinical translation to human patients is lacking.
2
The complex microenvironment of SCI requires multifaceted approaches, and single-condition changes may not be sufficient for effective repair.
3
Long-term effects of biomaterial-based therapies on SCI recovery require further investigation.

Your Feedback

Was this summary helpful?

Back to Spinal Cord Injury