Pasquinelli Gianandrea, Tazzari Pierluigi, Ricci Francesca, Vaselli Cristiana, Buzzi Marina, Conte Roberto, Orrico Catia, Foroni Laura, Stella Andrea, Alviano Francesco, Bagnara Gian Paolo, Lucarelli Enrico
Section of Clinical Pathology, Department of Experimental Pathology, University of Bologna, Bologna, Italy.
Ultrastruct Pathol. 2007 Jan-Feb;31(1):23-31. doi: 10.1080/01913120601169477.
Human mesenchymal stromal (stem) cells (hMSCs) isolated from adult bone marrow (BM-hMSCs) as well as amnion (AM-hMSCs) and chorion (CM-hMSCs) term placenta leaves were studied by transmission electron microscopy (TEM) to investigate their ultrastructural basic phenotype. At flow cytometry, the isolated cells showed a homogeneous expression of markers commonly used to identify hMSCs, i.e., CD105, CD44, CD90, CD166, HLA-ABC positivities, and CD45, AC133, and HLA-DR negativities. However, TEM revealed subtle yet significant differences. BM-hMSCs had mesenchymal features with dilated cisternae of rough endoplasmic reticulum (rER) and peripheral collections of multiloculated clear blisters; this latter finding mostly representing complex foldings of the plasma membrane could be revelatory of the in situ cell arrangement in the niche microenvironment. Unlike BM-hMSCs, CM-hMSCs were more primitive and metabolically quiescent, their major features being the presence of rER stacks and large peripheral collections of unbound glycogen. AM-hMSCs showed a hybrid epithelial-mesenchymal ultrastructural phenotype; epithelial characters included non-intestinal-type surface microvilli, intracytoplasmic lumina lined with microvilli, and intercellular junctions; mesenchymal features included rER profiles, lipid droplets, and well-developed foci of contractile filaments with dense bodies. These features are consistent with the view that AM-hMSCs have a pluripotent potential. In conclusion, this study documents that ultrastructural differences exist among phenotypically similar hMSCs derived from human bone marrow and term placenta leaves; such differences could be revelatory of the hMSCs in vitro differentiation potential and may provide useful clues to attempt their in situ identification.
采用透射电子显微镜（TEM）对从成人骨髓（BM-hMSCs）以及足月胎盘羊膜（AM-hMSCs）和绒毛膜（CM-hMSCs）中分离出的人间充质基质（干）细胞（hMSCs）进行研究，以探究其超微结构基本表型。在流式细胞术中，分离出的细胞显示出常用于鉴定hMSCs的标志物的均匀表达，即CD105、CD44、CD90、CD166、HLA-ABC呈阳性，而CD45、AC133和HLA-DR呈阴性。然而，TEM显示出细微但显著的差异。BM-hMSCs具有间充质特征，粗面内质网（rER）的池扩张，周边有多泡状透明水泡聚集；后一发现大多代表质膜的复杂折叠，可能揭示了其在生态位微环境中的原位细胞排列。与BM-hMSCs不同，CM-hMSCs更原始且代谢静止，其主要特征是存在rER堆叠和大量未结合糖原的周边聚集。AM-hMSCs表现出上皮-间充质混合超微结构表型；上皮特征包括非肠型表面微绒毛、内衬微绒毛的胞质内管腔和细胞间连接；间充质特征包括rER轮廓、脂滴以及具有致密小体的发达收缩丝灶。这些特征与AM-hMSCs具有多能潜力的观点一致。总之，本研究证明，源自人骨髓和足月胎盘叶的表型相似的hMSCs之间存在超微结构差异；这种差异可能揭示hMSCs的体外分化潜力，并可能为尝试其原位鉴定提供有用线索。
