Objective: To study the expansion potential of megakaryocyte progenitor cells (MPC) from human placenta tissue CD133+ (PT-CD133+) cells.
Methods: PT-CD133+ cells were purified from mononuclear cells (MNC) by magnetic activated cell sorting (MACS) and seeded in serum-free liquid culture medium supplemented with thrombopoietin (TPO), interleukin-3 (IL-3), and stem cell factor (SCF) to expand MPC. At day 7, 10 and 14, the total cell number was counted and the dynamic changes of CD133, CD34, and CD41 antigens expression during ex-vivo expansion were analyzed by flow cytometry (FCM). PT-CD133+ cells at different expansion time were collected and cultured in collagen semisolid medium for colony forming units-megakaryocyte (CFU-MK) assay.
Results: PT-CD133+ cells could be optimally expanded at day 7 by 13 +/- 2 fold increase in serum-free liquid culture systems and the total cell number was expanded by 160 fold at day 14. With the expansion time going on, the expression of CD133, CD34 decreased and that of CD41 increased. The expanded megakaryocytes were immature and no sign of platelet formation. Both PT-CD133+ cells before and after expansion could form CFU-MK, the total number of CFU-MK peaked at day 10 of expansion by 54 +/- 10 fold increase.
Conclusion: Human PT-CD133+ cells have a high capacity of MPC expansion, 10 days culture could give rise to the maximum number of CFU-MK.