FIG. 4.

Increasing pH and adding nicotinamide (NIC) increase high-ploidy Mk production. CD34⁺ HSPCs were seeded in X-VIVO 10 with cocktail “c” (Table 1) using interleukin (IL)-3 from R&D Systems and maintained at 5% O₂ and pH 7.2. On day 5, cells were washed, resuspended at pH 7.4/20% O₂, and supplemented with cocktail 3. (A, C, E) On day 7, cells were washed and resuspended in media supplemented with cocktail 3 and adjusted to pH 7.4 (squares) or 7.6 (triangles). (B, D, F) On day 7, cells from different cultures were washed and resuspended in media at pH 7.4 or 7.6 supplemented with cocktail 3. On day 7 (circles) or 8 (triangles), cultures at pH 7.4 (solid) and 7.6 (open) were supplemented with 6.25 mM NIC. (A, B) Total cell fold-expansion, (C, D) the number of CD41⁺ cells produced per input HSPC, and (E, F) the number of high-ploidy (>4N) Mks produced per input HSPC. Data represent the mean±SEM for n=3 donors.