Cavazzana-Calvo M, Lagresle C, André-Schmutz I, Hacein-Bey-Abina S
Département de biothérapie, Hôpital Necker enfants malades, 149, rue de Sèvres, 75743 Paris.
Ann Biol Clin (Paris). 2004 Mar-Apr;62(2):131-8.
Hematopoietic stem cells (HSC) have been widely used for autologous and allodeneic transplantation during decades, although little was known about their migration, survival, self-renewal and differentiation process. Their sorting by the CD34(+) marker they express at the cell surface in human has been challenged by the recent discovery of HSC in the CD34(-) compartment that may precede CD34(+) HSC in the differentiation process. Until recently, stem cells present in the bone marrow were thought to be specific for hematopoiesis. Some experiments including clinical trials showing the formation of various tissues, muscle, neural cells and hepatocytes for instance, after transplantation of medullar cells, have challenged this dogma. In fact, the proofs of such a transdifferentiation process by HSC are still missing and the observations may result from the differentiation of other mulipotent stem cells present in the bone marrow, such as mesenchymal stem cells and more primitive multipotent adult progenitor cells (MAPC) and side population (SP) cells.
几十年来，造血干细胞（HSC）已被广泛用于自体和异体移植，尽管人们对其迁移、存活、自我更新和分化过程知之甚少。人类造血干细胞通过其在细胞表面表达的CD34(+)标志物进行分选，这一方法受到了近期发现的挑战，即CD34(-)细胞区室中存在造血干细胞，它们在分化过程中可能先于CD34(+)造血干细胞出现。直到最近，骨髓中存在的干细胞仍被认为是造血特异性的。一些实验，包括临床试验，显示在移植骨髓细胞后可形成各种组织，如肌肉、神经细胞和肝细胞，这对这一传统观念提出了挑战。事实上，造血干细胞发生这种转分化过程的证据仍然缺乏，这些观察结果可能是由骨髓中存在的其他多能干细胞分化所致，如间充质干细胞、更原始的多能成人祖细胞（MAPC）和侧群（SP）细胞。
