TLR4 and metabolic dysfunction-associated steatotic liver disease: Fetuin-A (Fet-A), the first hepatokine discovered to have a significant pathogenic effect in NAFLD, facilitates the presentation of FFA to toll-like receptor 4 (TLR4) by inducing AT macrophage infiltration and M1 polarization, thereby triggering a series of inflammatory responses (Cayatte et al., 1990).