Ultrastructural characteristics of human mesenchymal stromal (stem) cells derived from bone marrow and term placenta

Gianandrea Pasquinelli, Pierluigi Tazzari, Francesca Ricci, Cristiana Vaselli, Marina Buzzi, Roberto Conte, Catia Orrico, Laura Foroni, Andrea Stella, Francesco Alviano, Gian Paolo Bagnara, Enrico Lucarelli

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124 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)23-31
Number of pages9
JournalUltrastructural Pathology
Issue number1
StatePublished - Feb 2007


  • Amnion human mesenchymal stromal cells
  • Bone marrow human mesenchymal stromal cells
  • Chorion membrane human mesenchymal stromal cells
  • Flow cytometry
  • Mesenchymal stem cells
  • Mesenchymal stromal cells
  • Transmission electron microscopy

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Structural Biology


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