The tracking of immunofluorescent labeled hematopoietic stem and progenitor cells (HSC/HPC) within the bone marrow (BM) cavity allows the assessment of the regulatory processes involved in transendothelial migration, trans-marrow migration, and finally lodgement into the HSC niche. This is of interest as the extracellular and cellular components involved in the regulation of HSC quiescence and differentiation are still not completely understood. Homing of transplanted HSC is the first critical step in the interaction between HSC and the microenvironment of the BM. As a consequence, murine models allowing the evaluation of the structural relationship between migrating HSC, the endosteal bone surface, and the vascular components of the BM enhance our understanding of hematopoietic regulation.
