TGFB1 and anemia: To evaluate the platelet contribution to the increased plasma TGF-β1 levels induced by phlebotomy, we induced anemia using low-iron diet and large-volume (300-500 μL) phlebotomies (Figure 4A) in a cohort of WT-C57Bl/6 mice (n = 7) and mice deficient in platelet TGF-β1 (PF4CreTgfb1flox/flox; n = 8).22