[Isolation and enrichment of hematopoietic stem/progenitor cells from human placenta tissue]

The aim of this study was to establish the standard protocols for isolating and enriching hematopoietic stem/progenitor cells (HSPC) from human placenta tissue (PT). Single-cell suspension from of human PT was prepared by mechanical method combined with collagenase digestion. Mononucleated cells (MNC) derived from PT were separated by hydroxyethyl starch (6% HES), then the three cell subsets of different immunophenotypes (CD34(-), CD34(+)CD38(-), CD34(+)CD38(+)) contained in MNC were isolated by Magnetic Activated Cell Sorting (MACS). The cell immunophenotype of each sorting steps was analyzed by flow cytometer (FCM). The cell enrichment and recovery rate of each sorting step were calculated. The results showed that MNC could be harvested up to (12.30 +/- 3.51) x 10(8) from a single-cell suspension of human PT by mechanical method and collagenase digestion, no significant difference existed as compared with umbilical cord blood (UCB) initial sample [(8.86 +/- 5.38) x 10(8)], but the percentage of CD34(+) cells in MNC of human PT was (3.93 +/- 2.31)%, much higher than that in UCB [(0.44 +/- 0.29)%] (P < 0.001). recovery rate of MNC and CD34(+) cells from PT after separation with 6% HES were (45.3 +/- 11.7)% and (51.1 +/- 9.8)%, respectively. After MNC being sorted by MACS, the enrichment and recovery rate of CD34(+) cells in CD34(+) group were (73.4 +/- 14.1)% and (52.7 +/- 11.7)% respectively. It is concluded that the protocols established here for isolating and enriching hematopoietic stem/progenitor cells from human placenta can acquire HSPC with high abundance, enrichment and viability and may be a useful reference of isolating methods for future related study.