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Background & Aims: Cholestasis is a liver disorder characterized by impaired bile flow, reduction of bile acids (BAs) in the intestine, and retention of BAs in the liver. The farnesoid X receptor (FXR) is the transcriptional regulator of BA homeostasis. Activation of FXR by BAs reduces circulating BA levels in a feedback mechanism, repressing hepatic cholesterol 7α-hydroxylase (Cyp7a1), the rate-limiting enzyme for the conversion of cholesterol to BAs. This mechanism involves the hepatic nuclear receptor small heterodimer partner and the intestinal fibroblast growth factor (FGF) 19 and 15. We investigated the role of activation of intestine-specific FXR in reducing hepatic levels of BAs and protecting the liver from cholestasis in mice., Methods: We generated transgenic mice that express a constitutively active FXR in the intestine. Using FXR gain- and loss-of-function models, we studied the roles of intestinal FXR in mice with intrahepatic and extrahepatic cholestasis., Results: Selective activation of intestinal FXR induced FGF15 and repressed hepatic Cyp7a1, reducing the pool size of BAs and changing the BA pool composition. Activation of intestinal FXR protected mice from obstructive extrahepatic cholestasis after bile duct ligation or administration of α-naphthylisothiocyanate. In Mdr2(-/-) mice, transgenic expression of activated FXR in the intestine protected against liver damage, whereas absence of FXR promoted progression of liver disease., Conclusions: Activation of FXR transcription in the intestine protects the liver from cholestasis in mice by inducing FGF15 expression and reducing the hepatic pool of BA; this approach might be developed to reverse cholestasis in patients., (Copyright © 2012 AGA Institute. Published by Elsevier Inc. All rights reserved.)

In a prospective study, we examined the impact of arterial hypervascularity, as established by the European Association for the Study of the Liver (EASL) recommendations, as a criterion for characterizing small (1-3 cm) nodules in cirrhosis. A total of 72 nodules (1-2 cm, n = 41; 2.1-3 cm, n = 31) detected by ultrasonography in 59 patients with cirrhosis were included in the study. When coincidental arterial hypervascularity was detected at contrast perfusional ultrasonography and helical computed tomography, the lesion was considered to be hepatocellular carcinoma (HCC) according to EASL criteria. When one or both techniques showed negative results, ultrasound-guided biopsy was performed. In cases with negative results for malignancy or high-grade dysplasia, biopsy was repeated when an increase in size was detected at the 3-month follow-up examination. Coincidental hypervascularity was found in 44 of 72 nodules (61%; 44% of 1-2-cm nodules and 84% of 2-3-cm nodules). Fourteen nodules (19.4%) had negative results with both techniques (hypovascular nodules). Biopsy showed HCC in 5 hypovascular nodules and in 11 of 14 nodules with hypervascularity using only one technique. All nodules larger than 2 cm finally resulted to be HCC. Not satisfying the EASL imaging criteria for diagnosis were 38% of HCCs 1 to 2 cm (17% hypovascular) and 16% of those 2 to 3 cm (none hypovascular). In conclusion, the noninvasive EASL criteria for diagnosis of HCC are satisfied in only 61% of small nodules in cirrhosis; thus, biopsy frequently is required in this setting. Relying on imaging techniques in nodules of 1 to 2 cm would miss the diagnosis of HCC in up to 38% of cases. Any nodule larger than 2 cm should be regarded as highly suspicious for HCC.

To investigate structural relationship between amphibian and mammalian GSTs the complete amino acid sequence of the major form of glutathione transferase present in toad liver (Bufo bufo) was determined. The enzyme subunit is composed of 210 amino acid residues corresponding to a molecular mass of 24,178 Da. In comparison with the primary structure of amphibian bbGSTP1-1, toad liver GST showed 54% sequence identity. On the other hand, toad liver GST showed about 45-55% sequence identity when compared with other pi class GST and less then 25% identity with GST of other classes. Amino acid residues involved in the H site and in the key and lock structure of the toad enzyme are significantly different from those of bbGSTP1-1 and other mammalian pi class GST. On the basis of its structural and immunological properties the toad liver GST, indicated as bbGSTP2-2, could represent the prototype of a subset of the pi family., (Copyright 2002 Elsevier Science Ltd.)

Background: Hepatic arterial Doppler sonography is increasingly being used in liver diagnostics. The determinants of the elevation of hepatic artery impedance indexes in chronic liver disease, however, have still not been fully clarified. The aim of the present study was to investigate the relationship between histological alterations and liver circulation in chronic hepatitis. Methods: Hepatic artery resistance index and portal flow velocity were measured using Doppler sonography in 47 patients with chronic hepatitis of viral origin diagnosed at histopathology. The patients were divided into two groups, those with mild and those with severe alterations, in accordance with the various histological parameters of the Knodell scoring system. Results: Hepatic artery resistance index and age were higher in patients with more severe liver fibrosis (respectively 0.638 ± 0.084 and 39.0 ± 10.9 (years) in mild fibrosis versus 0.687 ± 0.060 and 49.4 ± 14.4 (years) in severe fibrosis; P < 0.05 for both), whereas no difference between the two groups was found for the other histological features (degeneration, inflammation and necrosis), nor for portal flow velocity. Conclusions: The increase in hepatic artery resistance index appears to be influenced by the extent of fibrous tissue deposition in the liver, determined by chronic inflammation and repair and, secondly, by ageing. [ABSTRACT FROM AUTHOR]