High aldehyde dehydrogenase (ALDH) activity has been associated with stem and progenitor cells in various tissues. Human cord blood and bone marrow ALDH-bright (ALDHbr) cells have displayed angiogenic activity in preclinical studies and have been shown to be safe in clinical trials in patients with ischemic cardiovascular disease. The presence of ALDHbrcells in the heart has not been evaluated so far. We have characterized ALDHbrcells isolated from mouse hearts. One percent of nonmyocytic cells from neonatal and adult hearts were ALDHbr. ALDHvery-brcells were more frequent in neonatal hearts than adult. ALDHbrcells were more frequent in atria than ventricles. Expression of ALDH1A1 isozyme transcripts was highest in ALDHvery-brcells, intermediate in ALDHbrcells, and lowest in ALDHdimcells. ALDH1A2 expression was highest in ALDHvery-brcells, intermediate in ALDHdimcells, and lowest in ALDHbrcells. ALDH1A3 and ALDH2 expression was detectable in ALDHvery-brand ALDHbrcells, unlike ALDHdimcells, albeit at lower levels compared with ALDH1A1 and ALDH1A2. Freshly isolated ALDHbrcells were enriched for cells expressing stem cell antigen-1, CD34, CD90, CD44, and CD106. ALDHbrcells, unlike ALDHdimcells, could be grown in culture for more than 40 passages. They expressed sarcomericα-actinin and could be differentiated along multiple mesenchymal lineages. However, the proportion of ALDHbrcells declined with cell passage. In conclusion, the cardiac-derived ALDHbrpopulation is enriched for progenitor cells that exhibit mesenchymal progenitor-like characteristics and can be expanded in culture. The regenerative potential of cardiac-derived ALDHbrcells remains to be evaluated.
898. Human Hematopoietic Repopulating Stem and Progenitor Cells Can Be Efficiently Selected Based on High Aldehyde Dehydrogenase Activity
