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Unique megakaryocytes and platelets from novel human adipose-derived mesenchymal stem cell line

Keiichi Tozawa, Yukako Ono-Uruga, Masaki Yazawa, Taisuke Mori, Mitsuru Murata, Shinichiro Okamoto, Yasuo Ikeda and Yumiko Matsubara

Key points

  • Manufacturing platelets were obtained from novel human adipose-derived mesenchymal stem/stromal cells (ASCL) as a donor-independent source.

  • ASCL-derived platelets have characterization for other platelet population and might have an additional function as mesenchymal-like cells.

Abstract

The clinical needs for platelet transfusions are increasing. Donor-dependent platelet transfusions are, however, associated with practical problems, such as the limited supply and the risk of infection. Thus, we developed a manufacturing system for platelets from donor-independent cell source, human adipose-derived mesenchymal stromal/stem cell line (ASCL). ASCL was obtained by upside-down culture flask method. ASCL satisfied the minimal criteria for defining mesenchymal stem cell (MSC) by The International Society for Cellular Therapy. ASCL showed their proliferation capacity for at least 2 months without any abnormal karyotypes. ASCL was cultured in megakaryocyte induction media. ASCL-derived megakaryocyte (ASCL-MK) were obtained with a peak at Day 8 of culture. ASCL-derived platelets (ASCL-PLT) were obtained with a peak at Day 12 of culture. We observed that CD42b-positive cells expressed an MSC marker CD90 in relation to cell adhesion. Compared with peripheral platelets, ASCL-PLT exhibits higher levels of PAC1 binding, P-selectin surface exposure, ristocetin-induced platelet aggregation, and ADP-induced platelet aggregation; similar levels of fibrinogen binding, and collagen-induced platelet aggregation. ASCL-PLT has lower epinephrine-induced platelet aggregation. The pattern of in vivo kinetics after being infused into irradiated immunodeficient NSG mice was similar to that of platelet concentrates. ASCL-PLT has characterization observed in other platelet populations and might have an additional function as MSC. Neither the establishment of ASCL nor its differentiation into ASCL-PLT requires gene transfer, and endogenous thrombopoietin is utilized for differentiation. The present protocol is a simple method that requires no feeder cells, further enhancing the clinical application of our approach.

  • Submitted April 12, 2018.
  • Accepted October 2, 2018.