成人多组织器官中胚胎后亚全能干细胞的分离与鉴定

Identification and isolation of postembryonic sub-totipotent stem cells from various human adult tissue

目的:探讨成人多种组织中是否存在胚胎后亚全能干细胞。方法:用免疫磁珠从成人的多种组织中分离到CD105+细胞后,通过极限稀释法获得单克隆细胞,体外扩增并鉴定其生物学特性。结果:从成人的多种组织中分离得到的单克隆源细胞体外已传35代,免疫表型与脂肪源Flk1+CD31-CD34-细胞一致,即Flk1及CD44阳性,而CD31、CD34、CD45、HLAⅠ类抗原及HLA-DR阴性;细胞形态与脂肪源Flk1+CD31-CD34-细胞相似,呈成纤维样;在对数生长期,细胞倍增时间也与脂肪源Flk1+CD31-CD34-细胞一致,约为30h;体外可被定向诱导为在细胞形态及表型上与脂肪细胞、成骨细胞、神经细胞及肝上皮样细胞一致的细胞。结论:人体多种组织中均存在胚胎后亚全能干细胞,可用胚胎后亚全能干细胞学说来解释干细胞的可塑性。

Aim： To identify whether there are postembryonic sub-totipotent stem cells （SSCs） in various adult tissues. Mathods：CD105^＋ cells from diverse adult tissues were obtained by means of micromagnetic beads. The eluted cells were cloned by measure of limiting dilution. The single clone was harvested, expanded and characterized. Results： Single cell-derived clones were expanded in culture for more than 35 cell doublings and the phenotype of these stem cells from different adult tissues was similar to adult adipose tissue-derived Flk1^＋CD31^-CD34^- SSCs ： Flk1 and CD44 positive, CD31, CD34, CD45, class Ⅰ-HLA, and HLA-DR negative. Morphologically, these cells were fibroblast-like and the doubling time was about 30 hours. More importantly, culture-expanded pluripotent stem cells from all these adult tissues maintained the potential of differentiating into cells with morphologic and phenotypic characteristics of adipocytes, osteocytes, neurons, glia, and hepatocytes. Conclusion： The SSCs with characteristics similar to adult adipose tissue-derived Flk1^＋CD31^-CD34^- cells can be selected and cultured from tissues other than adipose tissue, and this phenomenon may help explain the stem cell plasticity found in multiple human tissues.