Compositions and methods of transplanting cells by grafting strategies into solid organs (especially internal organs) are provided. These methods and compositions can be used to repair diseased organs or to establish models of disease states in experimental hosts. The method involves attachment onto the surface of a tissue or organ, a patch graft, containing the donor cells. The donor cells may be a mixture of stem cells/progenitors with supporting early lineage stage mesenchymal cells. The patch graft promotes migration of the donor cells into the host organ and supports the successful integration of donor cells with host cells to repair the diseased organ.
