FIG. 1.

Characterization of human cardiac progenitor cells (hCPCs). The phenotype of hCPCs at passage 3 after immunomagnetic selection for c-kit. (a) At this passage, cells stably expressed the mesenchymal stem cells markers, Sca-1 and CD44, while the expression of c-kit was already declined (see the Results section for more details). These cells expressed also CD90 and CD105. Representative cytograms and a graph relative to the analysis of the five hCPC preparations, each one analyzed in two independent experiments±SD, are reported. (b) In reverse transcription-PCR analysis, the early cardiac markers, GATA-4, MEF2C, and TBX-5, were detectable in samples from all the patients, although at different levels. A similar variability was observed also when growth factor expression was analyzed. In few cases, the cognate receptors could not be detected. One representative experiment series out of the three performed with similar results is reported. hH, human heart tissue used as control.