OBJECTIVETo explore the supportive effects of stromal cells from human aorta-gonad-mesonephros (AGM) region on umbilical cord blood CD34+ cells.

METHODSStromal cells derived from human AGM region (hAGMS1-S5) and fetal trunk fibroblasts (hFf) were cultured on the bottom of 24-well plates as feeder cells. CD34+ cells positively selected from human umbilical cord blood through immunomagnetic beads selection method, were seeded into 24-well plates, and co-cultured for 28d. The number of total nucleated cells (TNC), CD34+ cells, CD34+ CD38- cells, and CFC were counted every week.

RESULTSStromal cells from human AGM region significantly supported proliferation of the TNC, CD34+ cells, CD34+ CD38- cells and CFC, when compared with hFT and controls without feeder cells (P < 0.05). The TNC increased (25.13 +/- 4.83)-fold (peak value) at day 21 in group of co-culture with AGM stromal cells. CD34 and CD34+ CD38- cells increased (2.68 +/- 0.51)- and (2. 38 +/- 0.45)-fold respectively at day 14 of co-culture. In colony analysis, HPP-CFU increased (2.62 +/- 0.85)-fold at day 14 of co-culture. The supportive effects of human AGM S1-S5 were significantly different, hAGM S3 and S4 were better than hAGM SI, S2, and S5 (P < 0.05).

CONCLUSIONSHuman AGM stromal cells S1-S5 could support the maintenance and expansion of umbilical cord blood CD34+ cells in vitro. hAGMS3, S4 cell had better effects on maintaining HSC activity, which would provide model cells and basic data for researches on hematopoiesis mechanism and hematopoietic differentiation of embryonic stem cells.