Commitment of human mesenchymal stromal cells to skeletal lineages is independent of their morphogenetic capacity

Figure 1 Validation of the recombinant limb system using human mesenchymal stromal cells. A: Implantation efficiency of umbilical cord blood (UCB)-recombinant limb (RLs) and placenta (PL)-RLs in chicken embryos after 24 h. Scanning electron microscopy of PL-RLs (n = 3) and UCB-RLs (n = 2) at 24 h postimplantation (hpi). The embryonic ectoderm and apical ectodermal ridge were conserved in RLs from both sources; B: Levels of human leukocyte antigen (Hla) detected by quantitative polymerase chain reaction at 24 hpi RLs from PL and UCB relative to its own pellet. Data represent three independent experiments. The major histocompatibility complex (HLA) expression pattern is shown in RLs from PL (n = 3) and UCB (n = 2). HLA expression was observed in the center of the RLs, indicating that mesenchymal stromal cells constituted the RLs. Statistical significance was set as follows: ^aP < 0.05; ^cP < 0.0005. UCB: Umbilical cord blood; PL: Placenta; RL: Recombinant limb; HLA: Human leukocyte antigen.