Dzierzak E
Department of Cell Biology and Genetics, Medical Faculty, Erasmus University, Rotterdam, The Netherlands.
Ann N Y Acad Sci. 1999 Apr 30;872:256-62; discussion 262-4. doi: 10.1111/j.1749-6632.1999.tb08470.x.
The ability of the many cell types within the adult blood system to be constantly replenished and renewed from hematopoietic stem cells is an interesting problem in development and differentiation and has led to questions concerning how, when and where these stem cells for the adult hematopoietic system are generated within the embryo. During embryonic development many mature hematopoietic cells appear before adult-type hematopoietic stem cells thus the notion of a conventional hematopoietic hierarchy is challenged. Experiments probing the development of hematopoietic stem cells in the mouse embryo strongly suggest that at least two independent hematopoietic sites generate blood cells during development; the yolk sac, which produces the transient embryonic hematopoietic system, and the AGM (aorta-gonad-mesonephros) region, which initiates the long-lived adult hematopoietic system.
成体血液系统中的多种细胞类型能够不断地从造血干细胞中得到补充和更新，这是发育与分化领域一个有趣的问题，也引发了关于胚胎中成人造血系统的这些干细胞是如何、何时以及在何处产生的疑问。在胚胎发育过程中，许多成熟的造血细胞在成人型造血干细胞出现之前就已出现，因此传统造血层级的概念受到了挑战。对小鼠胚胎中造血干细胞发育进行探究的实验有力地表明，在发育过程中至少有两个独立的造血部位产生血细胞；卵黄囊产生短暂的胚胎造血系统，而主动脉-性腺-中肾（AGM）区域启动了长寿的成人造血系统。
