TNFSF11 and osteoporosis: Intravital imaging and flow cytometric analysis showed a significant increase in EGFP-positive cells in the bone marrow under RANKL stimulation (Fig. 2 F and G), suggesting increased vascular permeability and the preferential recruitment of monocyte/macrophage lineage cells (e.g., osteoclast precursors) (17) into the bone marrow spaces as a feature of osteoporosis.