Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P17174 (aspartate aminotransferase)
 14,872 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Laboratory tests for the noninvasive diagnosis of liver fibrosis were studied extensively in the past. However, no test is yet accepted to replace liver biopsy as the gold standard. The establishment of widely accepted semiquantitative histologic scoring systems for the grading and staging of chronic liver disease (e.g., Ishak, Metavir and Scheuer) was paralleled by a significant upturn of research in circulating markers of liver fibrosis. We are now experiencing the renaissance of standard clinical chemistry markers, which are assembled to multiparameter scores (e.g., aspartate aminotransferase-to-platelet ratio index, FibroTest, Forns' index). These scores still require comprehensive evaluation in comparison with histology. Better understanding of the pathophysiology of liver fibrosis provided new options regarding circulating markers of hepatic matrix metabolism (e.g., hyaluronic acid, laminin, matrix metalloproteinase-2, aminoterminal propeptide of procollagen type III and tissue inhibitors of metalloproteinases-1). Several promising studies have been published to date. Thus, a redefinition of the role of liver biopsy is expected in the foreseeable future.
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PMID:Noninvasive diagnosis of fibrosis in chronic liver disease. 1534 64

In addition to regulating blood pressure and body fluid homeostasis, the renin-angiotensin system (RAS) is also involved in hepatic fibrogenesis. We aimed to investigate the effect of losartan, an angiotensin II (Ang II) antagonist, on CCl4-induced hepatic fibrosis in rats. Hepatic fibrosis was induced by a subcutaneous injection with 50% CCl4 in Sprague-Dawley rats. The amount of CCl4 administered was 1 mg/kg. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels in plasma and hydroxyproline (Hyp) contents in liver tissue were assayed by spectrophotometry. Hyaluronic acid (HA) and procollagen III (PC III) were assessed by radioimmunoassay. Tumor necrosis factor-alpha (TNF-alpha) and transforming growth factor-beta1 (TGF-beta1) levels in culture supernatants of Kupffer cells (KCs) stimulated with Ang II was determined by ELISA. Liver samples collected after 12 weeks of CCl4 treatment were stained with hematoxylin and eosin, then scored. Losartan (2.5, 5, and 10 mg x kg(-1), ig) and captopril (100 mg x kg(-1), ig) significantly decreased liver and spleen indexes, serum transaminase (AST, ALT) activities, HA and PC III levels, and Hyp contents in liver tissue in rats of hepatic fibrosis. Histopathological scores showed that losartan had an inhibitory effect on the progression of hepatic fibrosis. In in vitro experiments, losartan (1 x 10(-9) - 1 x 10(-5) M) significantly reduced TNF-alpha and TGF-beta1 levels in culture supernatants of KCs, but captopril (1 x 10(-5) M) did not. The results showed that losartan significantly inhibited the progression of hepatic fibrosis induced by CCl4, and the inhibitory effect of losartan on hepatic fibrosis might be associated with its ability to inhibit the production of TNF-alpha and TGF-beta1 by activated KCs.
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PMID:Effect of losartan, an angiotensin II antagonist, on hepatic fibrosis induced by CCl4 in rats. 1557 10

Normothermic preservation has been shown to be advantageous in an experimental model of preservation of non-heart-beating donor (NHBD) livers, which have undergone significant warm ischemic injury. The logistics of clinical organ retrieval might dictate a period of cold preservation prior to warm perfusion. We have investigated the effects of a brief period of cold preservation on NHBD livers prior to normothermic preservation. Porcine livers were subjected to 60 minutes of warm ischaemia and then assigned to following groups: Group W (n = 5), normothermic preservation for 24 hours; and Group C (n = 6), cold preservation in University of Wisconsin solution for 1 hour followed by normothermic preservation for 23 hours (total preservation time, 24 hours). Synthetic function (bile production and factor V production) and cellular damage were compared on the ex vivo circuit during preservation. There was no significant difference in the synthetic function of the livers (bile production and factor V production). Markers of hepatocellular damage (alanine aminotransferase and aspartate aminotransferase release), sinusoidal endothelial cell dysfunction (hyaluronic acid), and Kupffer cell injury (beta-galactosidase) were significantly higher in Group C. The histology of the livers at the end of perfusion was similar. In conclusion, a brief-period cold preservation prior to normothermic perfusion maintains the synthetic function and metabolic activity but results in significant hepatocellular damage, sinusoidal endothelial cell dysfunction, and Kupffer cell injury. Transplant studies are required to establish whether livers treated in this way are viable for transplantation.
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PMID:Non-heart-beating donor porcine livers: the adverse effect of cooling. 1569 May 34

We have evaluated the involvement of hepatic preconditioning mediators (adenosine, adenosine A1 and A2 receptors) during normothermic recirculation (NR) in a model of liver transplantation from non-heart-beating donor (NHBD) pigs. Application of NR after 20 min of warm ischemia (WI) reversed the lethal injury associated with transplantation of NHBD livers (achieving 5-day survival and diminishing glutathione S-transferase (GST), aspartate aminotransferase (AST) and hyaluronic acid (HA)). Adenosine administration prior to WI simulated the effect of NR. Measuring adenosine, we found that during NR, hepatic adenosine levels increased and xanthine levels decreased. Then when we blocked A2 receptors the effect of NR was abolished, whereas the blocking of A1 receptors further protected the liver. Furthermore, A2 blocking improved hepatic perfusion during NR whereas A1 blocking reduced it. The study suggests that NR has a preconditioning effect by maintaining adequate adenosine and xanthine levels. During NR, adenosine protects the liver through A2 activation and damages it through A1 activation although simultaneous stimulation of both receptors exerts a clear beneficial effect. The possible relation of NR mechanism with other preconditioning mediators such as cAMP and nitric oxide synthesis are discussed.
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PMID:The effect of normothermic recirculation is mediated by ischemic preconditioning in NHBD liver transplantation. 1616 86

Astragalosides is the major active constituent of Radix Astragali. The present study was carried out to investigate the effect of crude astragalosides fraction (CAF) on rats liver fibrosis and its possible mechanisms. Hepatic fibrosis was induced by subcutaneous injection with 50% CCl(4) in Sprague-Dawley rats. The amount of CCl(4) administered was 1 mg kg(-1). The alanine aminotransferase (ALT), aspartate aminotransferase (AST) levels in plasma and hydroxyproline (Hyp), malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GSH-px) contents in liver tissue were assayed by spectrophotometry. The hyaluronic acid (HA) and procollagen III (PC III) were assessed by radioimmunoassay. Tumor necrosis factor-alpha (TNF-alpha) and transforming growth factor-beta1 (TGF-beta1) levels in culture supernatants of Kupffer cells (KCs) were determined with ELISA. Liver samples collected after 8 weeks of CCl(4) treatment were stained with hematoxylin-eosin (HE) and massion, and scored. Intragastric administration of CAF (10, 20 and 40 mg kg(-1)) significantly decreased indices of liver and spleen, the serum transaminase activities, HA and PC III levels, and Hyp and MDA contents in liver tissue in rats of hepatic fibrosis. Decreased SOD and GSH-px levels were reversed after administration of CAF. Histopathological scores showed CAF had inhibitory effect on the progression of hepatic fibrosis. In the in vitro experiments, CAF significantly reduced TNF-alpha and TGF-beta1 levels in culture supernatants of KCs. The results showed CAF significantly inhibited the progression of hepatic fibrosis induced by CCl(4), and the inhibitory effect of CAF on hepatic fibrosis might be associated with its ability to scavenge free radical and inhibit the production of TNF-alpha and TGF-beta1 from activated KCs.
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PMID:Effects and mechanisms of crude astragalosides fraction on liver fibrosis in rats. 1619 23

Nonalcoholic fatty liver disease (NAFLD) encompasses both simple steatosis and nonalcoholic steatohepatitis (NASH). Differentiation of these two entities requires histopathologic evaluation. The aim of this study was to establish a reliable diagnostic model for differentiating steatosis from steatohepatitis utilizing both clinical characteristics and a panel of biochemical markers of lipid peroxidation and fibrosis. Eighty subjects with biopsy proven NAFLD were enrolled, 39 with simple steatosis and 41 with histopathologic evidence of NASH. Demographic and laboratory data to include serologic testing for 8-epi-PGF(2alpha), transforming growth factor-beta (TGF-beta), adiponectin, and hyaluronic acid (HA) were obtained and compared between the two groups. There were significant differences between the two groups with respect to age (P=0.004), female gender (P=0.024), aspartate aminotransferase (AST) (P=0.028), body mass index (BMI) (P=0.003), fasting insulin (0.018), AST/alanine aminotransferase (ALT) ratio (AAR) (P=0.017), quantitative insulin sensitivity check index (QUICKI) (P=0.002), and HA (P=0.029). A composite index for distinguishing steatosis from NASH was calculated by summing the risk factors of age >or=50 years, female gender, AST>or=45 IU/l, BMI >or=30 mg/kg2, AAR>or=0.80, and HA>or=55 microg/l, and its accuracy was determined by receiver operating characteristic (ROC) analysis to be 0.763 (95% CI: 0.650-0.876). The presence of three or more risk factors had a sensitivity, specificity, PPV, and NPV of 73.7%, 65.7%, 68.2%, and 71.4%, respectively. In addition, HA at a cutoff of 45.3 microg/l was a good predictor of advanced fibrosis. In conclusion, we propose a noninvasive screening model for distinguishing simple steatosis from NASH. Identifying patients at risk for NASH will allow clinicians to more accurately determine who may benefit from liver biopsy.
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PMID:Clinical model for distinguishing nonalcoholic steatohepatitis from simple steatosis in patients with nonalcoholic fatty liver disease. 1644 52

The hepatoprotective effects of whey protein on two injections of D-galactosamine (300 mg/kg, i.p.) were investigated in rats fed a modified AIN-93M diet formulated with a protein source of casein or whey for 16 d. The whey protein-containing diet clearly suppressed an increase in plasma alanine and aspartate aminotransferase activity, lactate dehydrogenase and bilirubin, which are hepatitis markers, and also hyaluronic acid, a fibrosis marker. In addition, it suppressed histopathological signs of portal fibrosis, bile duct proliferation, and perivenular sclerosis. These results suggest that supplementation with whey protein can help prevent the development of hepatitis and portal fibrosis.
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PMID:Hepatoprotective effects of whey protein on D-galactosamine-induced hepatitis and liver fibrosis in rats. 1671 38

Following major tissue injury, hyaluronic acid production increases as a rapid response survival mechanism. Increased hyaluronic acid production and turnover are often associated with increased hyaluronidase activity, the enzyme that degrades hyaluronic acid. We investigated whether hyaluronic acid and hyaluronidase can be used as non-invasive markers of acute disease activity in hepatitis C by studying 26 patients with acute hepatitis C, 89 with chronic hepatitis C and 32 healthy controls. Chronic hepatitis C subjects were classified into five subgroups according to the stage of liver fibrosis. Serum aspartate aminotransferase and alanine aminotransferase activities and hyaluronic acid levels were increased in hepatitis C patients compared with the controls. Serum hyaluronic acid elevation correlated with disease progression. Serum hyaluronidase activities were also increased in patients compared with the controls, but decreased with disease progression. We conclude that both hyaluronidase and hyaluronic acid may be useful as early non-invasive serum indicators of disease activity in acute hepatitis C.
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PMID:Evaluation of serum hyaluronic acid level and hyaluronidase activity in acute and chronic hepatitis C. 1759 63

To assess the usefulness of oncostatin M (osm) gene therapy in liver regeneration, we examined whether the introduction of OSM cDNA enhances the regeneration of livers damaged by dimethylnitrosamine (DMN) in rats. Repeated injection of OSM cDNA enclosed in hemagglutinating virus of Japan envelope into the spleen resulted in the exclusive expression of OSM protein in Kupffer cells of the liver, which was accompanied by increases in body weight, liver weight, and serum albumin levels and the reduction of serum liver injury parameters (bilirubin, aspartate aminotransferase, and alanine aminotransferase) and a serum fibrosis parameter (hyaluronic acid). Histological examination showed that osm gene therapy reduced centrilobular necrosis and inflammatory cell infiltration and augmented hepatocyte proliferation. The apoptosis of hepatocytes and fibrosis were suppressed by osm gene therapy. Time-course studies on osm gene therapy before or after DMN treatment showed that this therapy was effective not only in enhancing regeneration of hepatocytes damaged by DMN but in preventing hepatic cytotoxicity caused by subsequent treatment with DMN. These results indicate that OSM is a key mediator for proliferation and anti-apoptosis of hepatocytes and suggest that osm gene therapy is useful, as preventive and curative means, for the treatment of patients with liver damage.
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PMID:Oncostatin M gene therapy attenuates liver damage induced by dimethylnitrosamine in rats. 1764 Sep 59

To assess the immediate and long-term effects of ischemic preconditioning (IPC) in deceased donor. liver transplantation (LT), we designed a prospective, randomized controlled trial involving 60 donors: control group (CTL, n = 30) or study group (IPC, n = 30). IPC was induced by 10-min hiliar clamping immediately before recovery of organs. Clinical data and blood and liver samples were obtained in the donor and in the recipient for measurements. IPC significantly improved biochemical markers of liver cell function such as uric acid, hyaluronic acid and Hypoxia-Induced Factor-1 alpha (HIF-1 alpha) levels. Moreover, the degree of apoptosis was significantly lower in the IPC group. On clinical basis, IPC significantly improved the serum aspartate aminotransferase (AST) levels and reduced the need for reoperation in the postoperative period. Moreover, the incidence of primary nonfunction (PNF) was lower in the IPC group, but did not achieve statistical significance. We conclude that 10-min IPC protects against I/R injury in deceased donor LT.
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PMID:Ischemic pre-conditioning in deceased donor liver transplantation: a prospective randomized clinical trial. 1769 62


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