Isolation and characterization of Placenta- MSC derived microvesicles

Mesenchymal stem cells (MSCs) are the key elements of bone marrow and facilitate HSC maintenance in an invitro co-culture system through the secretion of soluble factors and cell-cell contact. Cell-derived microvesicles (MVs) or microparticles have been described as a new mechanism of cell to cell communication. In this experimental study, we obtained three placenta tissues from mothers with the informed consent under sterile condition. MSCs were isolated from the placentas; after several passages, MVs were obtained from MSC-culture-conditioned media by ultracentrifugation. Thje MVs concentration was determined in two samples by Bradford method; then, we characterized them by Transmission Electron microscopy and flowcytometer. At day 14 of the isolation, placenta-MSCs were passaged with more time for their growth required compared to BM-MSC. A different size range of microvesicles, within 40 to 160nm, was observed. The mean concentration was 125µg/mL (minimum 100µg/mL and maximum 150µg/mL) and they expressed CD29, CD44, CD73, and CD105 on their surface such as BM-MSC derived microvesicles. Microvesicles express mesenchymal cell markers that are required for adhesion to other cells. So they can contribute to the effects of mesenchymal stem cells in various cultures such as co-culture with hematopoetic stem cells.