SMAD4 and cyclic hematopoiesis: Sections of LV from the CH group exhibited significant upregulation of the cardiac fibrotic marker genes SMAD-2, SMAD-3, SMAD-4, TGF-β, and NF-κβ as well as significant downregulation of Let-b7 and SMAD-7 compared to the Control group (all p < 0.001) (Fig. 4A–G).