Horwitz Edwin M
Department of Hematology-Oncology, Divisions of Stem Cell Transplantation and Experimental Hematology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
Arch Med Res. 2003 Nov-Dec;34(6):600-6. doi: 10.1016/j.arcmed.2003.09.006.
The fundamental principle of stem cell biology is that cells with the potential for both self-renewal and terminal differentiation into one or more cell types may be found in a given tissue. The corollary of this principle is that the stem cells give rise to tissues in which they reside, the so-called expected tissues. Many exciting discoveries reported over the last several years challenge this paradigm by showing that there are not only tissue-specific stem cells that differentiate to the expected mature cells, but also that tissue stem cells can differentiate into unexpected cell lineages, suggesting an enormous plasticity of differentiation. Hematopoietic stem cells, which have drawn the most attention, mesenchymal stem cells, and neural stem cells have been the focus of many investigations. However, recent studies directed toward hematopoietic stem cells have disputed the concept of stem cell plasticity, suggesting that experimental artifact or somatic cell fusion may account for reported observations of plasticity. Although the data are mounting, stem cell plasticity, strictly defined, has yet to be rigorously proven. Animal models to meticulously define the biology and potential plasticity of stem cells and pilot clinical trials to begin to explore the biology and therapeutic potential of human stem cells will both be vital to advance the field over the coming years.
干细胞生物学的基本原理是，在特定组织中可能存在具有自我更新能力以及向一种或多种细胞类型终末分化潜能的细胞。该原理的必然结果是，干细胞产生它们所驻留的组织，即所谓的预期组织。过去几年报道的许多令人兴奋的发现对这一范式提出了挑战，这些发现表明，不仅存在能分化为预期成熟细胞的组织特异性干细胞，而且组织干细胞还能分化为意外的细胞谱系，这表明分化具有巨大的可塑性。最受关注的造血干细胞、间充质干细胞和神经干细胞一直是许多研究的焦点。然而，最近针对造血干细胞的研究对干细胞可塑性的概念提出了质疑，表明实验假象或体细胞融合可能是报道的可塑性观察结果的原因。尽管数据不断增加，但严格定义的干细胞可塑性尚未得到严格证实。在未来几年，精心定义干细胞生物学和潜在可塑性的动物模型以及开始探索人类干细胞生物学和治疗潜力的临床试验对于推动该领域的发展都至关重要。
