Populations of stem cells and methods for their isolation and use are provided. These
stem cell populations comprise
aldehyde dehydrogenase positive (ALDHbr) cells isolated from
bone marrow, and ALDHbr CD105+ cells derived from any
stem cell source. These populations may also comprise cells expressing such surface markers as CD34, CD38, CD41, CD45, CD105, CD133, CD135, CD117, and HLA-DR, and / or are substantially free from such
cell surface markers as CD3, CD7, CD 10, CD 13, CD 14, C1319, CD33, CD35, CD56, CD 127, CD 138, and
glycophorin A. The
population may also comprise cells expressing CD90. The
stem cell populations of the invention are isolated from a stem
cell source such as
bone marrow,
peripheral blood,
umbilical cord blood, and fetal liver. Methods of the invention comprise isolating and purifying stem
cell populations from stem cell sources, and methods of using these cells to reconstitute, repair, and regenerate tissues.