Mesenchymal stem cell(MSC) homing is the process when the endogenous or exogenous MSC migrates to the target tissue in response to the chemotaxis of various factors. MSC transplantation has been explored as a new clinical approach to repair injured tissues. However, the low rate of homing to target tissues and organs limits the therapeutic efficacy of MSC transplantation when used in stem cell therapy. We describe the known mechanisms of MSC homing after reviewing existing studies. A growing corpus of studies have highlighted three important aspects: 1)systemically administered MSC home to sites of injury; 2)the mechanism of MSC homing is very similar to that of leukocytes homing to the inflammatory region; and 3)MSC homing is associated with many ligands and their receptors, including numerous molecules such as chemokines, adhesion molecules, growth factors, and enzymes (i.e., the binding of a ligand to its receptor expressed on MSC has an important function in MSC homing). Understanding the homing of MSC may contribute to the theoretical foundation for the clinical utilization of MSC.
