AKT1 and hydrops fetalis: The PDGF produced by activated macrophages can promote the process of HF by promoting the proliferation and migration of HSCs, activating HSCs through the PDGF-B, PDGF-C, PDGF-D/PDGFR-β pathways, and further strengthening the fibrosis response through the extracellular regulated protein kinase (ERK), AKT (a serine/threonine kinase), and NF-κB pathways (Bonnardel et al., 2019).