| [ Summary ] |
Primary sclerosing cholangitis (PSC) is a chronic progressive cholestatic liver disease, the etiology of which is supposedly heterogeneous and remains poorly defined. Several hypotheses on the etiology have been proposed to explain the association of PSC with ulcerative colitis, including autoimmunity, inflammation caused by toxic substances produced by enteric flora in the inflamed intestine, and abnormal immunoregulation by cytokines. Furthermore, ischemic vascular damage may also contribute to bile duct damage. Fibrogenesis around the bile ducts follows chronic inflammation, producing a characteristic annular fibrosis around the bile ducts. Several important molecular mechanisms regulating inflammation and fibrogenesis have been revealed by recent immunological and cell biological studies. Although our understanding of PSC etiology has been improved with modern medicine and the availability of animal models, further work is needed to test hypotheses using techniques of immunology and cell biology. |