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Stem Cells in Endocrinology - part 4

trong động vật gặm nhấm và lớp mầm của con người dòng endodermal dòng tế bào gốc (xem Bảng 1). Trẻ et al. (6,8) nghiên cứu sự biểu hiện của các dấu hiệu CD trong các tế bào gốc dòng mầm lớp được tạo ra từ các nhà tài trợ của con người bào thai, trẻ sơ sinh, người lớn, và lão khoa. | Chapter 4 Differentiation Potential of Adult Stem Cells 73 within rodent and human germ layer lineage endodermal stem cell lines see Table 1 . Young et al. 6 8 studied the expression of CD markers in germ layer lineage stem cells generated from human fetal neonatal adult and geriatric donors. They found that the mesodermal stem cell exhibited CD10 CD13 CD34 CD56 CD90 and MHC-I CD markers. They did not find expression of CD1a CD2 CD3 CD4 CD5 CD7 CD8 CD9 CD11b CD11c CD14 CD15 CD16 CD18 CD19 CD20 CD22 CD23 CD24 CD25 CD31 CD33 CD36 CD38 CD41 CD42b CD45 CD49d CD55 CD57 CD59 CD61 CD62E CD65 CD66e CD68 CD69 CD71 CD79 CD83 CD95 CD105 CD117 CD123 CD135 CD166 Glycophorin-A HLA-DRII FMC-7 Annexin-V or LIN cell surface markers. Other investigators have observed some variations on this pattern 3 . Once induced to differentiate germ layer lineage stem cells demonstrate phenotypic differentiation expression markers specific for their tissues and characteristic of the germ layer from which the cell was derived see Table 1 2 3 . Germ layer lineage stem cells are responsive to proliferation agents such as platelet-derived growth factors. They exhibit contact inhibition at confluence in vitro. These stem cells are unresponsive to lineage-induction agents that have actions outside their germ layer tissue lineage. For example germ layer lineage mesodermal stem cells are unresponsive to brain-derived neurotrophic factor which acts on ectodermal lineage cells and hepatocyte growth factor which acts on endodermal lineage cells but are responsive to bone morphogenetic protein-2 which acts on mesodermal lineage cells . They are unresponsive to progression agents that accelerate the time frame of expression for tissue-specific phenotypic differentiation expression markers. Germ layer lineage stem cells remain quiescent in a serum-free environment lacking proliferation agents lineage-induction agents progression agents and inhibitory factors 2-4 9 10 . Ectodermal mesodermal and endodermal .