Macrophage-Pulp Fibroblast Interactions Modulate Initial Dental Pulp Regeneration In Vitro

Area of Science:

• Dental Pulp Biology
• Tissue Engineering
• Immunology

Background:

• Injured fibroblasts are crucial for pulp inflammation and regeneration.
• Fibroblasts direct macrophage differentiation into pro-inflammatory (M1) or anti-inflammatory (M2) phenotypes.
• Understanding these interactions is key to modulating pulp healing.

Purpose of the Study:

• To investigate the effects of fibroblast-conditioned macrophages on dental pulp stem cell (DPSC) proliferation and migration.
• To assess the impact of these macrophages on neo-angiogenesis in pulp regeneration.
• To elucidate the role of fibroblast-macrophage crosstalk in initial pulp repair mechanisms.

Main Methods:

• Isolation and characterization of human dental pulp stem cells (DPSCs) and pulp fibroblasts.
• Stimulation of fibroblasts mimicking carious lesions (injury and Lipoteichoic Acid - LTA).
• Incubation of macrophages (M0) with stimulated fibroblast supernatants to induce M1/M2 differentiation; assessment of DPSC viability, migration, VEGF secretion, and endothelial cell neo-angiogenesis.

Main Results:

• Fibroblast supernatants induced macrophage differentiation, influencing DPSC and endothelial cell viability.
• M2-like macrophage secretomes promoted DPSC proliferation and endothelial cell organization (neo-angiogenesis).
• M1-like macrophage secretomes (from LTA-stimulated fibroblasts) enhanced DPSC migration and VEGF secretion.

Conclusions:

• Pulp fibroblasts dictate macrophage polarization (M1/M2) based on stimulation.
• Macrophage phenotypes subsequently modulate DPSC proliferation/migration and neo-angiogenesis.
• Cell-cell interactions are critical for initiating pulp tissue regeneration.