PDGFRB and Hepatic fibrosis: In previous studies using murine models, the combined use of BCAAs attenuated liver fibrosis through inhibition of the TGF-β1 signaling pathway by downregulating several key pathway components, including SMAD-4, P-SMAD3L, TIMP-1, PDGFRβ, p-ERK, and COL1A2 [12–14, 23].