948 resultados para LIVER CARCINOGENESIS
Resumo:
BACKGROUND: To update and compare mortality from primary liver cancer (PLC) and intrahepatic cholangiocarcinoma (ICC) in Europe in 1990-2010. MATERIALS AND METHODS: We used data from the World Health Organization (WHO) to compute age-standardized (world population) mortality rates, and used joinpoint analysis to identify substantial changes. RESULTS: Between 2002 and 2007, PLC rates in the European Union (EU) declined from 3.9 to 3.6/100,000 men. Around 2007, the highest male rates were in France (6.2/100,000), Spain (4.9), and Italy (4.0), while the lowest ones were in Sweden (1.1), the Netherlands (1.2), and the UK (1.8). In women, mortality was lower (0.8/100,000 in 2007 in the EU), and showed more favourable trends, with a decline of over 2% per year over the last two decades as compared with 0.4% in men, in the EU. In contrast, the EU mortality from ICC increased by around 9% in both sexes from 1990 to 2008, reaching rates of 1.1/100,000 men and 0.75/100,000 women. The highest rates were in UK, Germany, and France (1.2-1.5/100,000 men, 0.8-1.1/100,000 women). CONCLUSIONS: PLC mortality has become more uniform across Europe over recent years, with an overall decline; in contrast, ICC mortality has substantially increased in most Europe.
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The purpose was to evaluate the influence of radiologist's experience on the diagnostic yield and complications of a percutaneous liver biopsy (PLB) method. Six hundred patients underwent an ultrasound-guided PLB by an inexperienced operator in 25.2% of cases (experience of less than 15 percutaneous liver biopsies performed alone--group I) or by an experienced operator (experience of more than 150 percutaneous liver biopsies--group II). The two groups were well-matched with respect to sex, age, percentage with viral hepatitis without histological cirrhosis, number of needle passes, history of liver biopsy and pain before the biopsy. A histological diagnosis was available in 97.3% of cases without any significant difference between the two groups ( P=0.25). However, group II samples were significantly longer and contained more portal tracts ( P=0.01). Pain was mild immediately and 6 h after the biopsy, without significant difference between both groups. Eight vasovagal reactions (five in group II) and one arteriobiliary fistula (in group II) occurred. With the method of PLB used for this study, operator's experience did not influence either the final histological diagnosis or the degree of pain suffered.
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The progression of liver fibrosis in chronic hepatitis C has long been considered to be independent from viral genotypes. However, recent studies suggest an association between Hepatitis C virus (HCV) genotype 3 and accelerated liver disease progression. We completed a systematic review and meta-analysis of studies evaluating the association between HCV genotypes and fibrosis progression. PubMed, Embase and ISI Web of Knowledge databases were searched for cohort, cross-sectional and case-control studies on treatment-naïve HCV-infected adults in which liver fibrosis progression rate (FPR) was assessed by the ratio of fibrosis stage in one single biopsy to the duration of infection (single-biopsy studies) or from the change in fibrosis stage between two biopsies (paired biopsies studies). A random effect model was used to derive FPR among different HCV genotypes. Eight single-biopsy studies (3182 patients, mean/median duration of infection ranging from 9 to 21 years) and eight paired biopsies studies (mean interval between biopsies 2-12 years) met the selection criteria. The odds ratio for the association of genotype 3 with accelerated fibrosis progression was 1.52 (95% CI 1.12-2.07, P = 0.007) in single-biopsy studies and 1.37 (95% CI 0.87-2.17, P = 0.17) in paired biopsy studies. In conclusion, viral genotype 3 was associated with faster fibrosis progression in single-biopsy studies. This observation may have important consequences on the clinical management of genotype 3-infected patients. The association was not significant in paired biopsies studies, although the latter may be limited by important indication bias, short observation time and small sample size.
Resumo:
We have investigated if changes in hepatic lipid metabolism produced by old age are related to changes in liver peroxisome proliferator-activated receptor alpha (PPARalpha). Our results indicate that 18-month-old rats showed a marked decrease in the expression and activity of liver PPARalpha, as shown by significant reductions in PPARalpha mRNA, protein and binding activity, resulting in a reduction in the relative mRNA levels of PPARalpha target genes, such as liver-carnitine-palmitoyl transferase-I (CPT-I) and mitochondrial medium-chain acyl-CoA dehydrogenase (MCAD). Further, in accordance with a liver PPARalpha deficiency in old rats, treatment of old animals with a therapeutic dose of gemfibrozil (GFB) (3mg/kg per day, 21 days) was ineffective in reducing plasma triglyceride concentrations (TG), despite attaining a 50% reduction in TG when GFB was administered to young animals at the same dose and length of treatment. We hypothesize that the decrease in hepatic PPARalpha can be related to a state of leptin resistance present in old animals.
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The mammalian circadian clock plays a fundamental role in the liver by regulating fatty acid, glucose, and xenobiotic metabolism. Impairment of this rhythm has been shown to lead to diverse pathologies, including metabolic syndrome. Currently, it is supposed that the circadian clock regulates metabolism mostly by regulating expression of liver enzymes at the transcriptional level. Here, we show that the circadian clock also controls hepatic metabolism by synchronizing a secondary 12 hr period rhythm characterized by rhythmic activation of the IRE1alpha pathway in the endoplasmic reticulum. The absence of circadian clock perturbs this secondary clock and provokes deregulation of endoplasmic reticulum-localized enzymes. This leads to impaired lipid metabolism, resulting in aberrant activation of the sterol-regulated SREBP transcription factors. The resulting aberrant circadian lipid metabolism in mice devoid of the circadian clock could be involved in the appearance of the associated metabolic syndrome.
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AMP-activated protein kinase (AMPK) is a major therapeutic target for the treatment of diabetes. We investigated the effect of a short-term overexpression of AMPK specifically in the liver by adenovirus-mediated transfer of a gene encoding a constitutively active form of AMPKalpha2 (AMPKalpha2-CA). Hepatic AMPKalpha2-CA expression significantly decreased blood glucose levels and gluconeogenic gene expression. Hepatic expression of AMPKalpha2-CA in streptozotocin-induced and ob/ob diabetic mice abolished hyperglycemia and decreased gluconeogenic gene expression. In normal mouse liver, AMPKalpha2-CA considerably decreased the refeeding-induced transcriptional activation of genes encoding proteins involved in glycolysis and lipogenesis and their upstream regulators, SREBP-1 (sterol regulatory element-binding protein-1) and ChREBP (carbohydrate response element-binding protein). This resulted in decreases in hepatic glycogen synthesis and circulating lipid levels. Surprisingly, despite the inhibition of hepatic lipogenesis, expression of AMPKalpha2-CA led to fatty liver due to the accumulation of lipids released from adipose tissue. The relative scarcity of glucose due to AMPKalpha2-CA expression led to an increase in hepatic fatty acid oxidation and ketone bodies production as an alternative source of energy for peripheral tissues. Thus, short-term AMPK activation in the liver reduces blood glucose levels and results in a switch from glucose to fatty acid utilization to supply energy needs.
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Using isolated, in situ, single-pass perfused rat livers, incubations of freshly isolated hepatocytes, and sinusoidal membrane-enriched vesicles, we and others have shown the saturability of transport (efflux) of hepatic glutathione (GSH). These observations have implicated a carrier mechanism. Our present studies were designed to provide further evidence in support of a carrier mechanism for hepatic GSH efflux by demonstrating competition by liver-specific ligands which are taken up by hepatocytes. Perfusing livers with different substances, we found that: (a) sulfobromophthalein-GSH (BSP-GSH) had a dose-dependent and fully reversible inhibitory effect on GSH efflux, while GSH alone did not have any effect; (b) taurocholate had no inhibitory effect; (c) all of the organic anions studied, i.e., BSP, rose bengal, indocyanine green, and unconjugated bilirubin (UCB), manifested potent, dose-dependent inhibitory effects, with absence of toxic effects and complete reversibility of inhibition in the case of UCB. The inhibitory effects of UCB could be overcome partially by raising (CoCl2-induced) hepatic GSH concentration. Because of the physiological importance of UCB, we conducted a detailed study of its inhibitory kinetics in the isolated hepatocyte model in the range of circulating concentrations of UCB. Studies with Cl- -free media, to inhibit the uptake of UCB by hepatocytes, showed that the inhibition of GSH efflux by UCB is apparently from inside the cell. This point was confirmed by showing that the inhibition is overcome only when bilirubin-loaded cells are cleared of bilirubin (incubation with 5% bovine serum albumin). Using Gunn rat hepatocytes and purified bilirubin mono- and diglucuronides, we found that both UCB and glucuronide forms of bilirubin inhibit GSH efflux in a dose-dependent manner. We conclude that the organic anions, although taken up by a mechanism independent of GSH, may competitively inhibit the carrier for GSH efflux from inside the hepatocyte.
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Background and aim: Recurrent hepati tis C is a major cause of morbidity and mortality after li ver transpl ant ati on (LT), and optimal treatm ent algorithms have yet to be defined. Here, we present our experience of 22 patients with recurrent hepatitis C treated in our institution .Patients and methods: Twenty-two patients with hi stology-proven recurrent hepati tis Cafter LT were treated since 2003. Treatment was ini ti ated with pegylated interferon-a2a 135 IIg per week and ribavirin 400 mg per day in the majority of patients, and subsequent doses were adapted individllally based on on-treatment virologieal responses and c1inical and/or biochemical si de effeets.Results: On an intention-to-treat basis, ustained virological re ponse(SVR) was achieved in 12/21 (54.5%) patie nts (5/12 [41 .6%], 2/3 [67%], 4/5 [80%] and 1/2 [50%] of patients infected with genotypes 1,2,3 and 4, respectively). Two patients experieneed relap e and 6 did not respond to treatm ent (NR). Treatment duration ranged from 24 to 90 weeks. It was stopped prematurely due to adverse events in 6/22 (27.2%) patients (with SVR achieved in 2 patients, NR in 2 patients, and death of 2 patients: one patient awaiting retransplantation and a second patient with HCV-HJV co-infection and fibrosing cholestat ic hepatiti s, nine months after transplantation). Of note, SVR was achi eved in a patient \Vi th combined liver and kidney transplantation. Importantly, SVR \Vas ach ieved in some patients despite the lack ofan early virological response or HCV RNA negativity at week 24. Darbepoetin a and fil ~,'rasti m were used in 36% and 18%, respectively.Conclusion: Individually adapted treatment of recurrent hepatitis C canachieve SVR in a substantial proponion ofLT patients. Conventional stopping rules do not apply in this setting so that prolonged therapy may be useful in selected patients.
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The accuracy of peritoneoscopy and liver biopsy in the diagnosis of hepatic cirrhosis was compared in 473 consecutive patients submitted to both procedures. One hundred and fifty-two of them had cirrhosis diagnosed by one or both methods. There was 73% agreement between the two procedures. `Apparent' false-negative results were 17·7% for peritoneoscopy and 9·3% for liver biopsy. The incidence of false-negative results in the diagnosis of cirrhosis can be reduced by combining both procedures.
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BACKGROUND Animal model studies have shown that the colon tumour promoting effect of dietary fat depends not only on the amount but on its fatty acid composition. With respect to this, the effect of n9 fatty acids, present in olive oil, on colon carcinogenesis has been scarcely investigated. AIMS To assess the effect of an n9 fat diet on precancer events, carcinoma development, and changes in mucosal fatty acid composition and prostaglandin (PG)E2 formation in male Sprague-Dawley rats with azoxymethane induced colon cancer. METHODS Rats were divided into three groups to receive isocaloric diets (5% of the energy as fat) rich in n9, n3, or n6 fat, and were administered azoxymethane subcutaneously once a week for 11 weeks at a dose rate of 7.4 mg/kg body weight. Vehicle treated groups received an equal volume of normal saline. Groups of animals were colectomised at weeks 12 and 19 after the first dose of azoxymethane or saline. Mucosal fatty acids were assessed at 12 and 19 weeks. Aberrant crypt foci and the in vivo intracolonic release of PGE2 were assessed at week 12, and tumour formation at week 19. RESULTS Rats on the n6 diet were found to have colonic aberrant crypt foci and adenocarcinomas more often than those consuming either the n9 or n3 diet. There were no differences between the rats on the n9 and n3 diets. On the other hand, administration of both n9 and n3 diets was associated with a decrease in mucosal arachidonate concentrations as compared with the n6 diet. Carcinogen treatment induced an appreciable increase in PGE2 formation in rats fed the n6 diet, but not in those fed the n3 and n9 diets. CONCLUSIONS Dietary olive oil prevented the development of aberrant crypt foci and colon carcinomas in rats, suggesting that olive oil may have chemopreventive activity against colon carcinogenesis. These effects may be partly due to modulation of arachidonic acid metabolism and local PGE2synthesis.
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The characterisation of lymphocytes from liver biopsies indicates that 'activated' T lymphocytes are present in the liver in alcohol induced hepatitis, chronic active hepatitis (HBS+ve and -ve), and in primary biliary cirrhosis but not in inactive cirrhosis, chronic persistent hepatitis, extrahepatic and drug induced cholestasis. A greater percentage of lymphocytes bear Fc-receptors in chronic active hepatitis than in alcohol induced hepatitis or cholestatic liver disease. The concentration of 'activated' T cells in the peripheral blood in all groups studied was within the normal range, suggesting that the 'activated' T cells found in the liver were reacting to either native or foreign antigens within the liver. The data on Fc-receptor bearing cells are consistent with the involvement of antibody assisted K cell mediated cytotoxicity in chronic active hepatitis.
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This study was undertaken in the framework of a larger European project dealing with the characterization of fat co- and by-products from the food chain, available for feed uses. In this study, we compare the effects, on the fatty acid (FA) and tocol composition of chicken and rabbit tissues, of the addition to feeds of a palm fatty acid distillate, very low in trans fatty acids (TFA), and two levels of the corresponding hydrogenated by-product, containing intermediate and high levels of TFA. Thus, the experimental design included three treatments, formulated for each species, containing the three levels of TFA defined above. Obviously, due to the use of hydrogenated fats, the levels of saturated fatty acids (SFA) show clear differences between the three dietary treatments. The results show that diets high in TFA (76 g/kg fat) compared with those low in TFA (4.4 g/kg fat) led to a lower content of tocopherols and tocotrienols in tissues, although these differences were not always statistically significant, and show a different pattern for rabbit and chicken. The TFA content in meat, liver and plasma increased from low-to-high TFA feeds in both chicken and rabbit. However, the transfer ratios from feed were not proportional to the TFA levels in feeds, reflecting certain differences according to the animal species. Moreover, feeds containing fats higher in TFA induced significant changes in tissue SFA, monounsaturated fatty acids and polyunsaturated fatty acids composition, but different patterns can be described for chicken and rabbit and for each type of tissue.
Resumo:
The addition of some fat co- and by-products to feeds is usual nowadays; however, the regulations of their use are not always clear and vary between countries. For instance, the use of recycled cooking oils is not allowed in the European Union, but they are used in other countries. However, oils recovered from industrial frying processes could show satisfactory quality for this purpose. Here we studied the effects of including oils recovered from the frying industry in rabbit and chicken feeds (at 30 and 60 g/kg, respectively) on the fatty acid (FA) and tocol (tocopherol + tocotrienol) compositon of meat, liver and plasma, and on their oxidative stability. Three dietary treatments (replicated eight times) were compared: fresh non-used oil (LOX); oil discarded from the frying industry, having a high content of secondary oxidation compounds (HOX); and an intermediate level (MOX) obtained by mixing 50 : 50 of LOX and HOX. The FA composition of oil diets and tissues was assessed by GC, their tocol content by HPLC, the thiobarbituric acid value was used to assess tissue oxidation status, and the ferrous oxidation-xylenol orange method was used to assess the susceptibility of tissues to oxidation. Our results indicate that FA composition of rabbit and chicken meat, liver and plasma was scarcely altered by the addition of recovered frying oils to feed. Differences were encountered in the FA composition between species, which might be attributed mainly to differences in the FA digestion, absorption and metabolism between species, and to some physiological dietary factors (i.e. coprophagy in rabbits that involves fermentation with FA structure modification). The α-tocopherol (αT) content of tissues was reduced in response to the lower αT content in the recovered frying oil. Differences in the content of other tocols were encountered between chickens and rabbits, which might be attributable to the different tocol composition of their feeds, as well as to species differences in the digestion and metabolism of tocols. Tissue oxidation and susceptibility to oxidation were in general low and were not greatly affected by the degree of oxidation of the oil added to the feeds. The relative content of polyunsaturated fatty acids/αT in these types of samples would explain the differences observed between species in the susceptibility of each tissue to oxidation. According to our results, oils recovered from the frying industry could be useful for feed uses.
Resumo:
The genomic loci occupied by RNA polymerase (RNAP) III have been characterized in human culture cells by genome-wide chromatin immunoprecipitations, followed by deep sequencing (ChIP-seq). These studies have shown that only ∼40% of the annotated 622 human tRNA genes and pseudogenes are occupied by RNAP-III, and that these genes are often in open chromatin regions rich in active RNAP-II transcription units. We have used ChIP-seq to characterize RNAP-III-occupied loci in a differentiated tissue, the mouse liver. Our studies define the mouse liver RNAP-III-occupied loci including a conserved mammalian interspersed repeat (MIR) as a potential regulator of an RNAP-III subunit-encoding gene. They reveal that synteny relationships can be established between a number of human and mouse RNAP-III genes, and that the expression levels of these genes are significantly linked. They establish that variations within the A and B promoter boxes, as well as the strength of the terminator sequence, can strongly affect RNAP-III occupancy of tRNA genes. They reveal correlations with various genomic features that explain the observed variation of 81% of tRNA scores. In mouse liver, loci represented in the NCBI37/mm9 genome assembly that are clearly occupied by RNAP-III comprise 50 Rn5s (5S RNA) genes, 14 known non-tRNA RNAP-III genes, nine Rn4.5s (4.5S RNA) genes, and 29 SINEs. Moreover, out of the 433 annotated tRNA genes, half are occupied by RNAP-III. Transfer RNA gene expression levels reflect both an underlying genomic organization conserved in dividing human culture cells and resting mouse liver cells, and the particular promoter and terminator strengths of individual genes.