Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy.
Adv Exp Med Biol. 2019;1123:39-54. doi: 10.1007/978-3-030-11096-3_4.
Planarian (Platyhelminthes, Triclads) are free-living flatworms endowed with extraordinary regenerative capabilities, i.e., the ability to rebuild any missing body parts also from small fragments. Planarian regenerative capabilities fascinated scientific community since early 1800, including high-standing scientists such as J.T. Morgan and C. M. Child. Today, it is known that planarian regeneration is due to the presence of a wide population of stem cells, the so-called neoblasts. However, the understanding of the nature of cells orchestrating planarian regeneration was a long journey, and several questions still remain unanswered. In this chapter, beginning from the definition of the classical concept of neoblast, we review progressive discoveries that have brought to the modern view of these cells as a highly heterogeneous population of stem cells including pluripotent stem cells and undifferentiated populations of committed progenies.
涡虫（扁形动物门，三肠目）是自由生活的扁形动物，具有非凡的再生能力，即能够从小块组织中重建任何缺失的身体部位。自 19 世纪初以来，涡虫的再生能力一直吸引着科学界的关注，包括杰出的科学家如 J.T. 摩根和 C. M. 蔡尔德。如今，人们已经知道，涡虫的再生是由于存在大量的干细胞，即所谓的成体干细胞。然而，对于协调涡虫再生的细胞的本质的理解是一个漫长的过程，仍然有几个问题没有得到解答。在这一章中，我们从经典的成体干细胞概念开始，回顾了一系列的发现，这些发现使我们对这些细胞有了更现代的认识，即它们是一个高度异质性的干细胞群体，包括多能干细胞和未分化的定向祖细胞群体。
