Alveolar Bone Mesenchymal Stem Cells Exhibit Osteogenic Potential with Fewer Macrophages.

Background: Mesenchymal stem cells (MSCs) derived from various tissues demonstrate regenerative potential in bone tissue engineering. However, bone marrow-derived MSCs (BMSCs) often contain macrophage contamination, necessitating additional purification steps such as liposomal clodronate treatment. In contrast, alveolar bone MSCs alveolar bone-derived MSCs (aBMSCs) may offer a distinct advantage due to their lower macrophage contamination.

Methods: The aBMSCs were isolated from alveolar bone fragments through enzymatic digestion, and their macrophage contamination was compared to BMSCs using flow cytometry for MSC surface markers (CD44, CD105, CD90.2, CD140a) and macrophage markers (CD11b).

Results: The aBMSCs exhibited significantly lower macrophage contamination compared to BMSCs and maintained osteogenic potential. Under inflammatory conditions in the presence of interleukin-1β (IL-1β), aBMSCs maintained their osteogenic capacity-unlike BMSCs, whose differentiation was impaired-accompanied by further activation of Protocadherin FAT4 (FAT4), which is known to initiate the osteogenic differentiation trajectory of aBMSCs.

Conclusions: These results highlight aBMSCs as a promising cell source for bone regeneration, offering low macrophage contamination and sustained osteogenic potential under inflammatory conditions such as IL-1β exposure.