Although the underlying mechanism of the increased levels of glycerophospholipids and sphingolipids in the metformin and pioglitazone combined therapy group was unclear and still needs further investigation, evidence could be found that the PC and metformin attenuating lipopolysaccharide induced toll-like receptor 4 and pro-inflammatory cytokines overexpression depending on whether there is a combined presence of NAFLD [43]. Here, TLR4 is linked to metabolic dysfunction-associated steatotic liver disease.