An effective amount of a composition comprising a stem cell, a stem cell engraftment enhancer, and a carrier fluid, for use in the treatment of an individual having a disease or at risk of developing a disease, wherein the disease is a vascular-associated disease and/or a muscular disease. A composition comprising PGI2-overexpressing human mesenchymal stem cells (PGI2-hMSCs), and a carrier fluid； wherein an effective amount of the composition is administered via a single treatment stream as an intramuscular injection to an individual having a disease or at risk of developing a disease, wherein the disease is a vascular-associated disease and/or a muscular disease, and wherein stem cell engraftment is enhanced in said individual by greater than about 200%, when compared to stem cell engraftment in an individual treated with a composition lacking the stem cell engraftment enhancer.
