Pieri Laura, Vannucchi Maria Giuliana, Faussone-Pellegrini Maria Simonetta
Department of Anatomy, Histology and Forensic Medicine, University of Florence, Florence, Italy.
J Cell Mol Med. 2008 Oct;12(5B):1944-55. doi: 10.1111/j.1582-4934.2008.00461.x.
CD117 (or c-kit) is expressed by the interstitial cells of Cajal (ICC), which are located within the gastrointestinal (GI) muscle coat and directly involved in its motility. CD34 is expressed by several cell types some of which have features and location resembling the ICC; however, a sure identification of these cells is still lacking. In order to establish whether the CD34-positive cells of the human GI tract are to be considered as ICC subpopulation or a novel independent cell type, and to hypothesize their nature and role, we verified CD34 and CD117 receptor expression under light and fluorescence microscope and performed a routine and a CD34-immuno-electron microscopy. CD34-positive cells were seen in the entire human GI tract. In the muscularis propria, shared morphologies similar to the c-kit-positive cells, in the submucosa, resembled fibroblasts. Their ultrastructure resembled that of the fibrocytes/fibroblasts and of the interstitial Cajal-like cells (ICLC). Double labelling and immunoelectro-microscopy demonstrated that they are unequivocally different to the ICC and, due to the similarities with the ICLC, we identified them as ICLC. The novelty of these results is that two types of interstitial cells are present in the GI muscle coat of humans: the ICC and the ICLC. We hypothesize a mechanical role for the septal ICLC, those at the myenteric plexus level and those bordering the muscle layers; a helping role in neurotransmission is proposed for the ICLC intercalated with the intramuscular ICC, possibly in spreading the slow waves generated by the ICC. Furthermore, the possibility that the ICLC represent the adult mesenchymal stromal cells able to guarantee the ICC renewal deserves to be considered.
CD117（或c-kit）由位于胃肠道肌层内且直接参与其蠕动的 Cajal 间质细胞（ICC）表达。CD34 由几种细胞类型表达，其中一些细胞具有与 ICC 相似的特征和位置；然而，仍缺乏对这些细胞的确切鉴定。为了确定人类胃肠道中 CD34 阳性细胞是应被视为 ICC 亚群还是一种新的独立细胞类型，并推测它们的性质和作用，我们在光学显微镜和荧光显微镜下验证了 CD34 和 CD117 受体的表达，并进行了常规和 CD34 免疫电子显微镜检查。在整个人类胃肠道中均可见到 CD34 阳性细胞。在固有肌层中，其形态与 c-kit 阳性细胞相似，在黏膜下层则类似于成纤维细胞。它们的超微结构类似于纤维细胞/成纤维细胞和间质 Cajal 样细胞（ICLC）。双重标记和免疫电子显微镜表明它们与 ICC 明显不同，并且由于与 ICLC 相似，我们将它们鉴定为 ICLC。这些结果的新颖之处在于人类胃肠道肌层中存在两种类型的间质细胞：ICC 和 ICLC。我们推测隔膜 ICLC、肌间神经丛水平的 ICLC 以及与肌层相邻的 ICLC 具有机械作用；对于与肌内 ICC 相间的 ICLC，提出其在神经传递中起辅助作用，可能是在传播由 ICC 产生的慢波。此外，ICLC 代表能够保证 ICC 更新的成年间充质基质细胞这一可能性值得考虑。
