Human adipose tissue contains erythroid progenitors expressing fetal hemoglobin

Figure 6 Effects of time and cell culture conditions on the pattern of hemoglobin expression in erythroid cells. Individual burst-forming units-erythroid (BFU-E)-derived colonies generated in a methylcellulose-based medium were selected, pooled and analyzed for hemoglobin expression by flow cytometry. A: The kinetics of HbF⁺HbA^- cells, HbF^-HbA⁺ cells and HbF⁺HbA⁺ cells of erythroid cells in the different cultures over time are given. From top to bottom: erythroid cells derived from cord blood (CB) CD34⁺ cells, from peripheral blood (PB) CD34⁺ cells, from stromal vascular fraction (SVF) CD45⁺ cells and from SVF CD45^- cells. The results are expressed as the percentage of total Hb-expressing cells (CB CD34⁺ cells, n = 7; PB CD34⁺ cells, n = 4; SVF CD45⁺ cells, n = 10 and SVF CD45⁺cells, n = 10). The data are provided as the means ± SE; B: A parallel series of cultures were performed to examine the effect of serum deprivation and hypoxia (5% O₂) on hemoglobin expression. Control cultures were grown under conditions of normoxia (20% O₂) using a serum-containing medium. SVF cells, n = 10; CB CD34⁺ cells, n = 10; PB CD34⁺ cells, n = 4. BFU-E-derived erythroid cells were analyzed by flow cytometry for hemoglobin composition at day 15 of culture. The results are expressed as the percentage of total Hb-expressing cells. The data are provided as the mean ± SE. ^aP < 0.02, ^aP < 0.0001. ND: Not detected. CB: Cord blood; PB: Peripheral blood; SVF: Stromal vascular fraction.