Exosomal Growth Factors from Dental Pulp Stem Cells (DSPCs) and Macrophage Secretome: Impact on Osteoblast Viability

Abstract

Advances in immune engineering aim to accelerate tissue regeneration. Macrophages play a crucial role in regulating the initiation of regeneration, balancing it through pro-inflammatory (M1) and reparative (M2) activities. Exosomes from dental pulp stem cells (DPSCs) carry osteogenic signals that can promote bone formation and accelerate hard tissue recovery. DPSC-derived exosomes with macrophage secretome synergistically modulate immunity and enhance osteogenesis through the secretion of TGF-β, BMP-2, and IGF-1, thus representing a potential strategy for repairing large bone defects. The aim of this study was to measure the growth factor concentration of exosomes from DSPCs and macrophage secretome and their effects on osteoblast viability. This study measured osteogenic growth factors in DPSC and mononuclear cell (MNC) exosomes and in macrophage secretome isolated with ExoQuick, quantified TGF-β, BMP-2, and IGF-1 by ELISA (read at 450 nm), and assessed effects on MG63 osteoblast viability using the MTT assay. Statistical analysis used ANOVA with Games-Howell post hoc. Results showed macrophage secretome supplemented with FBS contained significantly higher TGF-β, BMP-2, and IGF-1 than DPSC or MNC exosomes, and produced the greatest osteoblast viability (>90%). Adding FBS increased measured growth factor levels. We concluded that macrophage secretome and DPSCs were primary sources of these growth factors and that FBS supplementation enhances their osteogenic potential to promote bone regeneration.