Figure 2.

The process of IBD developing into PSC and liver fibrosis. In the context of IBD, there is translocation of bacteria, metabolites, and pathogens to the brain, liver–biliary system, and circulatory system, causing damage associated with IBD. When these agents reach the hepatobiliary system, they lead to chronic injury, resulting in PSC. At this stage, the imbalance of bicarbonate (HCO₃₋) in BECs disrupts bile acid metabolism, impairs BEC function, and leads to cholestasis. Upregulated proteins such as CCL24 and P4HA2 perpetuate inflammatory responses and cellular aging. Peribiliary glands expand, and mutual transformation occurs between BECs, MSCs, and HSCs. If chronic injury persists, it eventually leads to liver fibrosis. BECs: biliary epithelial cells; HSCs: hepatic stellate cells; MSCs: myofibroblasts. Diagrams were created with the help of BioRender software (© 2024 BioRender).