Chapter 18: Homing of Mesenchymal Stromal Cells

Over the last years, Mesenchymal Stromal Cells (MSCs), also termed Mesenchymal Stem Cells have been studied in a still increasing number of tissue regenerative processes and as potential new treatment options for a substantial number of medical indications. In addition to the local application of MSCs which has been primarily studied e.g. in bone regeneration, cartilage replacement, as well as soft tissue and ligament repair, MSCs have been proposed in several further diseases as systemic or local intravascular applied cellular therapeutic, e.g. in a stress condition, to suppress or modulate immune reactions or to spur blood cells regeneration after hematopoietic stem cell transplantation.

This has created new interest and research activities on how MSCs, which grow in tissue culture as adherent fibroblasts, will behave when injected into the blood stream. Specific questions which have been raised include (a) the adhesion molecules which MSCs may use to co-ordinately interact with the vessel wall, (b) whether MSCs can follow tissue specific homing stimuli in a similar or analogous way as leukocytes, or (c) whether the intravenously (i.v.) transplanted MSCs will rather be eliminated e.g. by phagocytosis before or instead of entering into tissues. This chapter therefore wishes to highlight important fact of the current status on knowledge in this area.