Expansion of Hematopoietic Progenitors

Hematopoietic progenitor cells were expanded for up to seven days as described previously [34] (link) in StemSpan culture medium supplemented with 10 ng/mL stem cell factor (SCF; PeproTech GmbH, Hamburg, Germany), 20 ng/mL thrombopoietin (TPO; PeproTech), 10 ng/mL fibroblast growth factor 1 (FGF-1; PeproTech) and 10 µg/mL heparin (Roche GmbH, Mannheim, Germany) [32] (link). For co-culture experiments, addition of cytokines was not performed as MSCs alone activate proliferation. Culture medium was always supplemented with 10% serum of individual MDS patients or control samples as described in our previous work [31] (link).