ELT concentration and iron status influence the proliferation and apoptosis of committed MK progenitors. For these studies, CD34⁺cells were cultured for 7 days in iron-depleted, iron-deficient, and iron-replete conditions with 50 ng/mL of TPO to generate committed MK progenitors with variable iron status. At the end of 7 days, cells (mostly committed MK progenitors) were cultured for an additional 3 days in the same media but supplemented with TPO3 and escalating ELT concentrations. (A) Cell expansion improved with improved iron status and was maximal in cells preloaded with iron and cultured with ELT6. (B) Iron deficiency significantly reduced cell proliferation at all ELT concentrations but most strikingly in cells cultured with ELT30. (C) Treatment with ELT30 for 3 days significantly increased MK apoptosis in iron-depleted cells. This effect was attenuated in cells with improved iron status. (D) Representative images of EdU incorporation assays after FACS analysis: 0% HOLO and 0 µM ELT (left), 0% HOLO and 30 µM ELT (middle), and 100% HOLO and 30 µM ELT (right). EdU⁺ cells were identified by their red nuclear staining. CD41 was labeled in green, and DAPI was used for nuclear staining. N = 6 independent experiments. *P < .05; ***P < .001.