Methods and devices using non-autologous mesenchymal stem cells comprising treating a recipient in need thereof with an effective amount of non-autologous mesenchymal stem cells, including methods and preparations for treating and regenerating connective tissue and enhancing bone marrow engraftment in an individual; and for using genetically engineered allogeneic human mesenchymal stem cells that carry within them genes of interest particularly for the expression of physiologically or pharmacologically active proteins in gene therapy for correction of genetic disorders or "rebuilding" proteins important in tissue repair.