Cholestasis

About: Cholestasis is a research topic. Over the lifetime, 9494 publications have been published within this topic receiving 248684 citations. The topic is also known as: bile occlusion & obstruction of bile duct.

The Continuing Importance of Bile Acids in Liver and Intestinal Disease

Abstract: Bile acids, the water-soluble, amphipathic end products of cholesterol metabolism, are involved in liver, biliary, and intestinal disease. Formed in the liver, bile acids are absorbed actively from the small intestine, with each molecule undergoing multiple enterohepatic circulations before being excreted. After their synthesis from cholesterol, bile acids are conjugated with glycine or taurine, a process that makes them impermeable to cell membranes and permits high concentrations to persist in bile and intestinal content. The relation between the chemical structure and the multiple physiological functions of bile acids is reviewed. Bile acids induce biliary lipid secretion and solubilize cholesterol in bile, promoting its elimination. In the small intestine, bile acids solubilize dietary lipids promoting their absorption. Bile acids are cytotoxic when present in abnormally high concentrations. This may occur intracellularly, as occurs in the hepatocyte in cholestasis, or extracellulary, as occurs in the colon in patients with bile acid malabsorption. Disturbances in bile acid metabolism can be caused by (1) defective biosynthesis from cholesterol or defective conjugation, (2) defective membrane transport in the hepatocyte or ileal enterocyte, (3) defective transport between organs or biliary diversion, and (4) increased bacterial degradation during enterohepatic cycling. Bile acid therapy involves bile acid replacement in deficiency states or bile acid displacement by ursodeoxycholic acid, a noncytotoxic bile acid. In cholestatic liver disease, administration of ursodeoxycholic acid decreases hepatocyte injury by retained bile acids, improving liver tests, and slowing disease progression. Bile acid malabsorption may lead to high concentrations of bile acids in the colon and impaired colonic mucosal function; bile acid sequestrants provide symptomatic benefit for diarrhea. A knowledge of bile acid physiology and the perturbations of bile acid metabolism in liver and digestive disease should be useful for the internist.

An essential role for nuclear receptors SXR/PXR in detoxification of cholestatic bile acids.

Abstract: Hepatic hydroxylation is an essential step in the metabolism and excretion of bile acids and is necessary to avoid pathologic conditions such as cholestasis and liver damage. In this report, we demonstrate that the human xenobiotic receptor SXR (steroid and xenobiotic receptor) and its rodent homolog PXR (pregnane X receptor) serve as functional bile acid receptors in both cultured cells and animals. In particular, the secondary bile acid derivative lithocholic acid (LCA) is highly hepatotoxic and, as we show here, a metabolic substrate for CYP3A hydroxylation. By using combinations of knockout and transgenic animals, we show that activation of SXR/PXR is necessary and sufficient to both induce CYP3A enzymes and confer resistance to toxicity by LCA, as well as other xenotoxicants such as tribromoethanol and zoxazolamine. Therefore, we establish SXR and PXR as bile acid receptors and a role for the xenobiotic response in the detoxification of bile acids.

Molecular Pathogenesis of Cholestasis

Abstract: The formation of bile is a vital function, and its impairment by drugs or infectious, autoimmune, metabolic, or genetic disorders results in the syndrome commonly known as cholestasis.1 The secreti...

Primary sclerosing cholangitis: a review of its clinical features, cholangiography, and hepatic histology.

Abstract: Twenty-nine patients with primary sclerosing cholangitis were reviewed. Males predominated (2:1). Seventy-six per cent presented with cholestasis and cholangitis, 17% with cirrhosis and portal hypertension, and 7% were asymptomatic, presenting with a raised serum alkaline phosphatase. The serum immunoglobulin IgM concentration was raised in 45% of the patients, but no patient had serum mitochondrial antibody present. Seventy-two per cent had ulcerative proctocolitis. There was no relationship between either duration or severity of ulcerative proctocolitis and the development of primary sclerosing cholangitis. Four patients were not benefited by colectomy. None of the patients ahd Crohn's disease. The prognosis was variable. Corticosteriods and azathioprine were ineffective. Eleven patients (38%) had died with a mean survival time of seven years from diagnosis. Three patients with ulcerative proctocolitis developed bile duct carcinoma. The cholangiograms and liver biopsies were reported without reference to clinical information together with 41 patients with other biliary diseases. Cholangiography was diagnostic in 18/22 (82%). Hepatic histology was diagnostic in 8/22 (36%). Ten showed features of large bile duct disease and three were misdiagnosed as primary biliary cirrhosis. Reduced numbers of bile ducts, ductular proliferation, portal inflammation, and substantial copper deposition, in combination with piecemeal necrosis, are commonly seen in primary sclerosing cholangitis and indicate the need for cholangiography.

A gene encoding a P-type ATPase mutated in two forms of hereditary cholestasis.

Abstract: Cholestasis, or impaired bile flow, is an important but poorly understood manifestation of liver disease. Two clinically distinct forms of inherited cholestasis, benign recurrent intrahepatic cholestasis (BRIC) and progressive familial intrahepatic cholestasis type 1 (PFIC1), were previously mapped to 18q21. Haplotype analysis narrowed the candidate region for both diseases to the same interval of less than 1 cM, in which we identified a gene mutated in BRIC and PFIC1 patients. This gene (called FIC1) is the first identified human member of a recently described subfamily of P-type ATPases; ATP-dependent aminophospholipid transport is the previously described function of members of this subfamily. FIC1 is expressed in several epithelial tissues and, surprisingly, more strongly in small intestine than in liver. Its protein product is likely to play an essential role in enterohepatic circulation of bile acids; further characterization of FIC1 will facilitate understanding of normal bile formation and cholestasis.