Abstract 72: Subselected Adipocyte Progenitor Niche Cells Show Superior Incorporation and Function in a Mouse Model

RESULTS: Early pre-osseous lesions were highly enriched in eGFP+ circulating cells. These cells primarily co-stained for neutrophil (Ly6G+), macrophage (F4/80+), and trauma-reactive mesenchymal (PDGFRα+) markers consistent with acute inflammation and consequent mesenchymal condensation. Vascular (CD31+) and pericyte (CD105+) staining at the wound site demonstrated minimal co-staining. Bioluminescent signals persisted from oneto eight-weeks post-injury diminishing slightly by twelve weeks. Samples of developing tHO from this period demonstrated presence of eGFP (+) cells in fibroproliferative, cartilaginous, and stromal/marrow populations consistent with joint contribution to early endochondral ossification (SOX9+; OSX+) and to the development of a mature shared marrow space in the definitive osseous lesion.