Emura I, Sekiya M, Ohnishi Y
Arch Histol Jpn. 1983 Dec;46(5):645-62. doi: 10.1679/aohc.46.645.
Presumptive hemopoietic stem cells in the human liver obtained from 109 embryos 28 to 49 days after ovulation and 76 fetuses between 8 and 22 weeks of ovulation were investigated by light and electron microscopy. Presumptive hemopoietic stem cells in the human embryonic liver are concluded to be a series of cells that show a variegated ultrastructure. They are classified into four subtypes (type I, II, III and IV). Presumptive hemopoietic stem cells of type I are thought to differentiate from the undifferentiated mesenchymal cells that are derived from the septum transversum. Presumptive stem cells of type I, II and III transitorily appear in the liver during the early stage of hepatic hemopoiesis, and cannot be detected in late stages. With the development of the fetus, presumptive stem cells of the type IV, however, gradually increase in number. The cells of megakaryocytic, granulocytic and erythrocytic lineages originate from the presumptive stem cells of type II in the early stage of hepatic hemopoiesis, whereas the cells of the three lineages originate from the presumptive stem cells of type IV in the late stage. The presumptive hemopoietic stem cells of type IV are surmised as corresponding to the pluripotent hemopoietic stem cells (CFU-S) in laboratory animals or pluripotent hemopoietic progenitors in human bone marrow (CFU-mix).
对取自排卵后28至49天的109个胚胎以及排卵后8至22周的76个胎儿的人肝脏中的推定造血干细胞进行了光镜和电镜研究。人胚胎肝脏中的推定造血干细胞被认为是一系列具有多样化超微结构的细胞。它们被分为四个亚型（I型、II型、III型和IV型）。I型推定造血干细胞被认为是由源自横隔的未分化间充质细胞分化而来。I型、II型和III型推定干细胞在肝造血早期短暂出现在肝脏中，在后期无法检测到。然而，随着胎儿的发育，IV型推定干细胞数量逐渐增加。巨核细胞系、粒细胞系和红细胞系的细胞在肝造血早期起源于II型推定干细胞，而在后期这三个系的细胞起源于IV型推定干细胞。IV型推定造血干细胞被推测对应于实验动物中的多能造血干细胞（CFU-S）或人骨髓中的多能造血祖细胞（CFU-mix）。
