Lisinopril inhibits nuclear transcription factor kappa B and augments sensitivity to silymarin in experimental liver fibrosis.

Therapeutic interventions are still limited in the treatment of liver fibrosis even though an incredible number of publications related to silymarin are produced. This is due to the complex molecular pathogenesis. Several studies pointed to the role of renin-angiotensin system (RAS) in hepatic fibrogenesis. Therefore, the present study was designed to examine the effect of the combination of lisinopril (LIS) with silymarin (SIL) on CCl4-induced hepatic fibrosis along with an in-vitro confirmatory experiment. Rats were treated with LIS (1 mg kg-1) and SIL (30 mg kg-1) as a single agent and as combined to LIS (1 mg kg-1). Our results revealed that down-regulation of NFĸBp65 mRNA expression and inhibition of phosphorylation of NFĸBp65 (at Ser536) and NFĸBia were implicated in the anti-fibrotic effect of both LIS and SIL. Consequently lower levels of NFкB-induced TNF-α, TGF-ß1, MMP-2, TIMP-1 and VEGF compared to control group. In addition, levels of α-SMA protein expression and hydroxyproline are decreased in association with marked improvement in liver function, oxidative stress markers and histological picture. In addition, LIS augmented the inhibitory effect of SIL on NFĸB pathway at lower dose level. We concluded that LIS, via targeting NFĸB pathway, increases anti-oxidant capacity of liver tissue and exhibits anti-inflammatory, anti-fibrotic and anti-angiogenic activity and augments sensitivity to SIL. Therefore, LIS is a promising candidate for further clinical investigation in the treatment of liver fibrosis.

Pre-Hepatectomy Assessment of Bile Transporter Expression by Gadoxetic Acid-Enhanced MRI in a Rat Model of Liver Cirrhosis.

BACKGROUND: Gadoxetic acid is a liver-specific intravenous T1 magnetic resonance (MR) contrast agent that is excreted via the hepatobiliary system. We hypothesize that hepatocyte expressions of bile transporters (OATP1 and MRP2) correlate with dynamic profile of Gadoxetic acid enhanced (GE)-MR imaging (MRI). METHODS: Two groups of rats, control (n = 6) and cirrhosis (n = 12), received gadoxetic acid enhanced MRI followed by 70% hepatectomy. The change in MR signal intensity from the baseline before the contrast injection (ΔSI) was analyzed every minute for 30 min. Dynamic signal intensity retention ratio (DSR) was defined as the mean ΔSI of the third 10-minmin period divided by the first 10-minmin period. Real-time PCR was utilized to quantify mRNA expressions. RESULTS: Compared to the control, cirrhosis group demonstrated lower mRNA levels of OATP1 (0.038 ± 0.020 vs. 0.232 ± 0.0979; p = 0.004), MRP2 (0.201 ± 0.084 vs. 0.7567 ± 0.254; p = 0.002), and OATP1/MRP2 mRNA ratio (0.193 ± 0.065 vs. 0.342 ± 0.206; p = 0.032). DSR was higher in the cirrhosis group (0.678 ± 0.554 vs -0.125 ± 0.839; p = 0.033). In the cirrhosis group, there was an inverse correlation between the ratios of OATP1/MRP2 mRNA and DSR (R = -0.709, p = 0.01). CONCLUSION: Bile transporters OATP1/MRP2 mRNA expression ratio in rat liver tissue decreased with DMN-induced liver injury. The expressions of bile transporters correlated with GE-MRI DSR. The GE-MRI DSR has potential utility in qualifying OATP1/MRP2 mRNA expression.

The Synthetic Triterpenoid RTA 405 (CDDO-EA) Halts Progression of Liver Fibrosis and Reduces Hepatocellular Carcinoma Size Resulting in Increased Survival in an Experimental Model of Chronic Liver Injury.

UNLABELLED: Patients with cirrhosis have an increased risk of developing liver cancer and a higher rate of mortality. Cirrhosis currently has no known cure, and patients may benefit from new agents aimed at alleviating their complications and slowing down the rate of disease progression. Therefore, the effects of the orally bioavailable synthetic triterpenoid 2-cyano-3,12-dioxooleana- 1,9(11)-dien-28-oate-ethyl amide (CDDO-EA, RTA 405), which has potent antioxidative and antiinflammatory properties, was evaluated in a chronic carbon tetrachloride (CCl(4))-induced model of liver cirrhosis and hepatocellular carcinoma (HCC). Mice were injected with CCl(4) (to induce fibrosis and cirrhosis) or placebo biweekly for 12 weeks followed by CDDO-EA in the diet for 18 weeks with continued biweekly injections of CCl(4). Chronic CCl(4) administration resulted in cirrhosis, ascites, and HCC formation, associated with increased serum transforming growth factor-ß1, hepatic hydroxyproline content, and increased serum bilirubin. CDDO-EA, whose administration commenced after establishment of liver fibrosis, decreased liver fibrosis progression, serum bilirubin, ascites, and HCC formation and markedly increased overall survival. CDDO-EA also attenuated -TNFα (tumor necrosis factor-α), α-SMA (alpha smooth muscle actin), augmented -IL-10 levels, and improved histologic and serologic markers of fibrosis. CONCLUSIONS: CDDO-EA mitigates the progression of liver fibrosis induced by chronic CCl(4) administration, which is associated with the induction of antifibrogenic genes and suppression of profibrogenic genes.

Chronological production of thioacetamide-induced cirrhosis in the rat with no mortality.

BACKGROUND: Cirrhotic animal models are useful in studying complications of chronic liver disease. The authors chronologically investigated the effect of thioacetamide (TAA), administered intraperitoneally and adapted individually to weight changes, focusing on the optimal moment to obtain typical features of cirrhosis. MATERIAL AND METHOD: Male Wistar Rats,150-200 g, were intoxicated three times per week with TAA of 200 mg/kg for 4, 8, 12 or 16 weeks (n = 8 per group), respectively and compared with age-matched controls (n = 4 per group). The individual body weight and liver function test were also measured in each group. Liver samples from each group were histologically stained with Sirius red in order to identify the degree of liver fibrosis. RESULTS: Rats intoxicated for 4, 8, 12 or 16 weeks had no mortality and histologically showed hepatitis and advanced fibrosis. At 12 and 16 weeks, all animals showed macronodular cirrhosis with signs of high-grade hepatocellular dysplasia. The weight of the treated groups at different time points was significantly lower than the controls. Routine liver function tests between cirrhotic and control rats showed significantly higher only in alanine transaminase (ALT) and aspartate aminotransferase (AST) at 8 and 12 weeks. However in the cirrhotic rats at 16 weeks, the ALT and AST were much lower than that at 8 and 12 weeks but did not show any difference from the controls. CONCLUSION: Thioacetamide, adapted to individual weight changes, leads to a model of cirrhosis in the rat at 12 and 16 weeks with zero mortality.

Low-dose oral rapamycin treatment reduces fibrogenesis, improves liver function, and prolongs survival in rats with established liver cirrhosis.

BACKGROUND/AIMS: Mammalian target of rapamycin (mTOR) signalling is central in the activation of hepatic stellate cells (HSCs), the key source of extracellular matrix (ECM) in fibrotic liver. We tested the therapeutic potential of the mTOR inhibitor rapamycin in advanced cirrhosis. METHODS: Cirrhosis was induced by bile duct-ligation (BDL) or thioacetamide injections (TAA). Rats received oral rapamycin (0.5 mg/kg/day) for either 14 or 28 days. Untreated BDL and TAA-rats served as controls. Liver function was quantified by aminopyrine breath test. ECM and ECM-producing cells were quantified by morphometry. MMP-2 activity was measured by zymography. mRNA expression of procollagen-alpha1, transforming growth factor-beta1 (TGF-beta1) and beta2 was quantified by RT-PCR. RESULTS: Fourteen days of rapamycin improved liver function. Accumulation of ECM was decreased together with numbers of activated HSCs and MMP-2 activity in both animal models. TGF-beta1 mRNA was downregulated in TAA, TGF-beta2 mRNA was downregulated in BDL. 28 days of rapamycin treatment entailed a survival advantage of long-term treated BDL-rats. CONCLUSIONS: Low-dose rapamycin treatment is effectively antifibrotic and attenuates disease progression in advanced fibrosis. Our results warrant the clinical evaluation of rapamycin as an antifibrotic drug.

Safety limit of large-volume hepatic radiofrequency ablation in a rat model.

BACKGROUND: Large-volume hepatic radiofrequency ablation (RFA) has been used to treat large liver tumors, but its safety limit is unknown. This study aimed to investigate the possible systemic responses of large-volume hepatic RFA and to estimate its safety limit in normal and cirrhotic rats. HYPOTHESIS: Large-volume hepatic RFA causes a significant systemic inflammatory reaction. DESIGN: Experimental study. SETTING: University teaching hospital. INTERVENTION: Using the Cool-tip RF System (Radionics, Burlington, Mass), RFA was performed for different percentages of the liver volume by weight in normal and cirrhotic Sprague-Dawley rats. MAIN OUTCOME MEASURES: Changes in concentrations of serum inflammatory markers (tumor necrosis factor alpha [TNF-alpha] and interleukin [IL] 6), functions of various end organs, and survival rates were assessed. RESULTS: In the normal liver groups, the concentrations of TNF-alpha and IL-6 were significantly elevated in the early postoperative period when 50% (mean +/- SD TNF-alpha concentration, 130.3 +/- 15.6 pg/mL; mean +/- SD IL-6 concentration, 163.2 +/- 12.2 pg/mL) and 60% (mean +/- SD TNF-alpha concentration, 145.7 +/- 13.0 pg/mL; mean +/- SD IL-6 concentration, 180.8 +/- 11.0 pg/mL) of the liver volume were ablated compared with the control group (mean +/- SD TNF-alpha concentration, 30.4 +/- 9.9 pg/mL, P<.001; mean +/- SD IL-6 concentration, 28.4 +/- 6.7 pg/mL, P<.001). The concentrations of TNF-alpha and IL-6 in other groups remained similar to those in the control group. Thrombocytopenia, prolonged clotting time, and interstitial pneumonitis occurred when 50% and 60% of the liver volume were ablated. The 4-week survival rates were 100%, 60%, and 0% when 40%, 50%, and 60%, respectively, of the liver volume were ablated. Similar systemic inflammatory responses and poor survival rates were observed among the cirrhotic liver groups when 30% and 40% of the liver volume were ablated. CONCLUSIONS: The normal rats can tolerate RFA of 40% of the liver volume with minimal morbidity and no mortality whereas the cirrhotic rats can only tolerate 20% of the ablated liver volume. Beyond that limit, RFA would cause significant systemic inflammatory responses and poor survival.

Thalidomide salvages lethal hepatic necroinflammation and accelerates recovery from cirrhosis in rats.

BACKGROUND/AIMS: The authors investigated the feasibility of thalidomide employed to treat liver fibrosis. METHODS: A cirrhotic model was established using Sprague-Dawley rats fed thioacetamide. Thalidomide-treated group was given thalidomide (10mg/kg/day) intraperitoneally for 10 consecutive days. Mortality, histopathological changes, TNFalpha, TGFbeta1, TIMP-1 and TIMP-2 were determined. Expression of TNFalpha and TGFbeta1 mRNA of Kupffer's cells derived from the experimental rats were determined. RESULTS: The mortality rates of thalidomide-treated group and vehicle-treated group were 8 and 32%, respectively. The total Knodell score of thalidomide-treated rats was lower than those of vehicle-treated rats. Micro-nodular cirrhosis resolved grossly in thalidomide-treated rats on day 28; while vehicle-treated rats continued to display uneven liver surface on day 28. Expression of TNFalpha, TGFbeta1, TIMP-1, and TIMP-2 was decreased in thalidomide-treated rats compared to those treated with vehicles. Finally, the expression of TNFalpha and TGFbeta1 mRNA of Kupffer's cells derived from rats treated with thalidomide were much lower than those treated with vehicle. CONCLUSIONS: Thalidomide salvages lethal hepatic necroinflammation, accelerates recovery from cirrhosis in rats, and works by suppressing of TNFalpha and TGFbeta1 production of Kupffer's cells.

Halofuginone can worsen liver fibrosis in bile duct obstructed rats.

BACKGROUND/AIMS: Halofuginone (HF) is an antifibrotic agent in rat models of liver fibrosis caused by repetitive intoxications. A beneficial effect of HF on a biliary type of liver fibrosis has not been proven yet. METHODS: Bile duct-obstructed rats were given HF from the moment of obstruction onwards and compared with no treatment. After 3 weeks, respectively, 6 weeks, aminopyrine breath test (ABT) and haemodynamic measurements including of portal pressure were carried out. Liver pieces were taken for Sirius red quantitative scoring, as well as for semiquantitative determinations of collagen type I and III RNA levels. RESULTS: ABT was significantly worse in HF-treated rats as compared with no treatment (P=0.02). Haemodynamic data and collagen type I and III determinations were not significantly different between groups. Biliary fibrosis scores were significantly higher in HF-treated rats as compared with no treatment (P=0.03). More Sirius red staining was associated with more proliferation of bile ductules. CONCLUSIONS: HF may worsen biliary fibrosis. This contrasts sharply with antifibrotic effects in other models of liver fibrosis. Distinctive cellular mechanisms in biliary fibrosis may explain this discrepancy. One should be cautious for chronic application of HF in man with cholestasis.

Experimental studies on morphological changes of microcirculation of DMN-induced liver cirrhosis after normothermic ischemia with charge-coupled device microscope.

AIM: The purpose of the present experiment was to find indices for intraoperative ischemic-reperfusion injury in the cirrhotic liver. METHODS: One percent dimethylnitrosamine (DMN) was administered intraperitoneally to liver cirrhosis (LC) groups of Wister rats on three consecutive days of each week for a period of four weeks. The rats were divided into a N60 group with 60 minute ischemia in normal livers, a LC60 group with 60 minute ischemia in cirrhotic livers, and a LC30 group with 30 minute ischemia in cirrhotic livers. Digital videotapes recorded with a pencil lens-probe charge-coupled device (CCD) microscope were analyzed with NIH Image software. In zone 3, the sinusoid diameter (SD) was measured and the volume fraction (Vv) of zone 3 was calculated in preischemia and after 10, 20, 30, and 60 min of reperfusion. At the same time, bile flow was measured. RESULTS: The SD was significantly shorter in the cirrhotic liver groups than in the normal liver group at each point. The Vv after 60 min of reperfusion was significantly smaller in the LC60 group, with a survival rate of 0%, than in the LC30 group which had a survival rate of 67%. However, there was no significant difference in bile flow after 60 min of reperfusion in the LC30 and LC60 groups. Therefore, the Vv is suggested to be the better index for viability after ischemic-reperfusion. CONCLUSION: SD and Vv indicate microcirculatory differences and indices in the normal and cirrhotic livers in preischemia during reperfusion.

Safe upper limit of intermittent hepatic inflow occlusion for liver resection in cirrhotic rats.

AIM: To evaluate the effects of varying ischemic durations on cirrhotic liver and to determine the safe upper limit of repeated intermittent hepatic inflow occlusion. METHODS: Hepatic ischemia in cirrhotic rats was induced by clamping the common pedicle of left and median lobes after non-ischemic lobes resection. The cirrhotic rats were divided into six groups according to the duration and form of vascular clamping: sham occlusion (SO), intermittent occlusion for 10 (IO-10), 15(IO-15), 20(IO-20) and 30(IO-30) minutes with 5 minutes of reflow and continuous occlusion for 60 minutes (CO-60). All animals received a total duration of 60 minutes of hepatic inflow occlusion. Liver viability was investigated in relation of hepatic adenylate energy charge (EC). Triphenyltetrazollum chloride (TTC) reduction activities were assayed to qualitatively evaluate the degree of irreversible hepatocellular injury. The biochemical and morphological changes were also assessed and a 7-day mortality was observed. RESULTS: At 60 minutes after reperfusion following a total of 60 minutes of hepatic inflow occlusion, EC values in IO-10 (0.749 +/- 0.012) and IO-15 (0.699 +/- 0.002) groups were rapidly restored to that in SO group (0.748 +/- 0.016), TTC reduction activities remained in high levels (0.144 +/- 0.002 mg/mg protein, 0.139 +/- 0.003 mg/mg protein and 0.121 +/- 0.003 mg/mg protein in SO, IO-10 and IO-15 groups, respectively). But in IO-20 and IO-30 groups, EC levels were partly restored (0.457 +/- 0.023 and 0.534 +/- 0.027) accompanying with a significantly decreased TTC reduction activities (0.070 +/- 0.005 mg/mg protein and 0.061 +/- 0.003 mg/mg protein). No recovery in EC values (0.228 +/- 0.004) and a progressive decrease in TTC reduction activities (0.033 +/- 0.002 mg/mg protein) were shown in CO-60 group. Although not significantly different, the activities of the serum aspartate aminotransferase (AST) on the third postoperative day (POD(3)) and POD(7) and of the serum alanine aminotransferase (ALT) on POD(3) in CO-60 group remained higher than that in intermittent occlusion groups. Moreover, a 60% animal mortality rate and more severe morphological alterations were also shown in CO-60 group. CONCLUSION: Hepatic inflow occlusion during 60 minutes for liver resection in cirrhotic rats resulted in less hepatocellular injury when occlusion was intermittent rather than continuous. Each period of 15 minutes was the safe upper limit of repeated intermittent vascular occlusion that the cirrhotic liver could tolerate without undergoing irreversible hepatocellular injury.

Hepatocyte transplantation in rats with decompensated cirrhosis.

Hepatocyte transplantation improves the survival of laboratory animals with experimentally induced acute liver failure and the physiological abnormalities associated with liver-based metabolic deficiencies. The role of hepatocyte transplantation in treating decompensated liver cirrhosis, however, has not been studied in depth. To address this issue, cirrhosis was induced using phenobarbital and carbon tetrachloride (CCL(4)) and animals were studied only when evidence of liver failure did not improve when CCL(4) was held for 4 weeks. Animals received intrasplenic transplantation of syngeneic rat hepatocytes (G1); intraperitoneal transplantation of syngeneic rat hepatocytes (G2); intraperitoneal transplantation of a cellular homogenate of syngeneic rat hepatocytes (G3); intraperitoneal transplantation of syngeneic rat bone marrow cells (G4); or intrasplenic injection of Dulbecco's modified Eagle medium (DMEM) (G5). After transplantation, body weight and serum albumin levels deteriorated over time in all control (G2-G5) animals but did not deteriorate in animals receiving intrasplenic hepatocyte transplantation (G1) (P <.01). Prothrombin time (PT), total bilirubin, serum ammonia, and hepatic encephalopathy score were also significantly improved toward normal in animals receiving intrasplenic hepatocyte transplantation (P <. 01). More importantly, survival was prolonged after a single infusion of hepatocytes and a second infusion prolonged survival from 15 to 128 days (P <.01). Thus, hepatocyte transplantation can improve liver function and prolong the survival of rats with irreversible, decompensated cirrhosis and may be useful in the treatment of cirrhosis in humans.

Schistosome infection of transgenic mice defines distinct and contrasting pathogenic roles for IL-4 and IL-13: IL-13 is a profibrotic agent.

Experimental Schistosoma mansoni infections of mice lead to a dynamic type 2 cytokine-mediated pathological process. We have used IL-4-deficient, IL-13-deficient, and IL-4/13-deficient mice to dissect the role of these cytokines in the development of immune response and pathology following S. mansoni infection. We demonstrate that while both of these cytokines are necessary to develop a robust Th2 cell-driven, eosinophil-rich granuloma response, they also perform disparate functions that identify novel sites for therapeutic intervention. IL-13-deficient mice demonstrated significantly enhanced survival following infection, which correlated with reduced hepatic fibrosis. In contrast, increased mortality was manifest in IL-4-deficient and IL-4/13-deficient mice, and this correlated with hepatocyte damage and intestinal pathology. Therefore, we demonstrate that during a dynamic type 2 cytokine disease process IL-13 is detrimental to survival following infection, whereas IL-4 is beneficial.

Repeated concanavalin A challenge in mice induces an interleukin 10-producing phenotype and liver fibrosis.

Weekly injections of Concanavalin A (Con A) were performed in BALB/c mice to evaluate the pattern of cytokine production and liver injury. High serum levels of tumor necrosis factor alpha (TNF-alpha), interleukin 2 (IL-2), IL-4, and interferon gamma (IFN-gamma) were found in the serum after the first 2 injections of Con A but rapidly decreased from the third injection. Conversely, IL-10 serum levels after repeated Con A challenge increased by 7 times from week 1 to 20. In vivo depletion studies indicated that CD4(+) T cells are essential in IL-10 production. Hepatocyte necrosis was only observed after the first injections of Con A whereas centrilobular inflammatory infiltrates persisted up to 20 weeks. Perisinusoidal liver fibrosis was also increasingly detected in BALB/c mice, whereas no fibrous change was observed in nude mice after 6 weeks of Con A challenge. The number of stellate cells, detected by immunostaining, increased after 20 weeks of Con A injections. Liver cytokine messenger RNA (mRNA) expression after 20 weeks showed expression of transforming growth factor beta1 (TGF-beta1), IL-10, and IL-4 whereas IL-2 was no more expressed. The present study shows that mice repeatedly injected with Con A develop liver fibrosis. The cytokine-release pattern observed after 1 injection of Con A is rapidly shifted towards an immunomodulatory phenotype characterized by the systemic production of large amounts of IL-10.

Effect of long-term trimethoprim-sulfamethoxazole prophylaxis on ascites formation, bacterial translocation, spontaneous bacterial peritonitis, and survival in cirrhotic rats.

Selective intestinal decontamination with norfloxacin is useful in preventing spontaneous bacterial peritonitis in cirrhotic patients and also in cirrhotic rats. The emergence of norfloxacin-resistant infections in these patients warrants a search for alternative therapies. The aim of this study was to evaluate the effect of long-term trimethoprim-sulfamethoxazole administration on carbon tetrachloride (CCl4) -induced cirrhosis in rats with specific attention to intestinal flora, bacterial translocation, spontaneous bacterial peritonitis (SBP), and survival. Male Sprague-Dawley rats received CCl4 administered weekly by gavage. After eight weeks of CCl4 administration rats were randomly allocated into two groups. Group I received daily overnight trimethoprim-sulfamethoxazole diluted in phenobarbital water during follow-up and group II did not. The rats were killed when gravely ill, and a laparotomy was performed to culture samples of cecal stool, mesenteric lymph nodes, and portal and inferior vena caval blood. There was a trend toward a reduction in the incidence of bacterial translocation (8/17 vs 11/14, respectively) and SBP (5/17 vs 7/14, respectively) in treated rats that were killed just before death compared to untreated rats. A decrease in the incidence of bacterial translocation caused by gram-negative bacilli was observed in group I (17.6% vs 78.6%, P < 0.01). The development of ascites was delayed in group I (P < 0.05) and survival was prolonged in group I (P < 0.05), despite a higher CCl4 dose in this group (P < 0.05). In conclusion, long-term prophylactic trimethoprim-sulfamethoxazole administration in CCl4-induced cirrhosis in rats delayed the development of ascites, prolonged survival, and reduced the incidence of gram-negative bacterial translocation but not of SBP, without increasing gram-positive episodes. These data suggest that trimethoprim-sulfamethoxazole might be a good alternative to norfloxacin for preventing gram-negative bacterial translocation.

Liver fibrosis in guinea pigs experimentally induced by combined copper and aflatoxin application.

Aflatoxin B1 alone (0.05 mg resp. 0.037 mg/kg/d), copper alone (6.6 mg/kg/d or 200 mg/l drinking water) or a combination of both was administrated orally for 6 months to young guinea pigs from the first/second day of life. In the copper group there were no pathomorphological changes. For the aflatoxin B1 group liver damage was established. In the combined group liver injury was more frequent and more severe compared to the aflatoxin B1 group. Compared with the copper group biliary copper excretion was diminished and the kidney copper content was elevated in the Afl. B1 + Cu group. While copper concentrations in bile and kidney correlated with other parameters, notably the pathological lesions of the liver, no such correlation was found for liver copper. Therefore in this experiment the degree of Cu accumulation was not decisive for the liver lesions. The livers' capacity for excreting Cu by bile seems to be a much more important factor. Histologically only the livers of the combined group exhibited degeneration, atrophy and steatosis of liver cells, and a fibrosis more or less pronounced. For childhood cirrhosis (ICC and ICT), a combined etiology--a liver damaging agent plus elevated alimentary copper--is a plausible hypothesis.

Oral supplementation with branched-chain amino acids improves survival rate of rats with carbon tetrachloride-induced liver cirrhosis.

We investigated whether supplementation with branched-chain amino acids (BCAA) improves survival of rats with carbon tetrachloride (CCl4) -induced cirrhosis. Liver cirrhosis was induced in 40 male Sprague-Dawley rats by administering CCl4 for 15 weeks. Twenty rats each were then assigned to the control and BCAA group and fed a casein diet or a BCAA-supplemented casein diet, respectively, for an additional 17 weeks with repeated injections of CCl4. No significant difference occurred in either mean energy or nitrogen intake or in body or liver weight between the two groups. BCAA-supplementation significantly preserved plasma albumin concentrations (P < 0.05) and inhibited significantly the occurrence of ascites and hyperammonemia (P < 0.05). The survival rate was significantly higher in the BCAA group (P=0.03), while no significant difference was found in liver histology between the groups. These results suggest that BCAA improved survival of rats with CCl4-induced cirrhosis by preventing hypoalbuminemia and hyperammonemia without directly reducing hepatic necrosis and fibrosis.

Evaluation of the potential carcinogenicity and genetic toxicity to humans of the herbicide acetochlor.

Comprehensive toxicological studies of the herbicide acetochlor are presented and discussed. Although it gave a negative profile of responses in the many toxicity tests conducted there were some findings that prompted further investigation. First, although non-mutagenic in the Salmonella assay, acetochlor was clastogenic to mammalian cells treated in vitro. This clastogenic potential was not expressed in vivo in four rodent cytogenetic assays (bone marrow and germ cells). Second, although acetochlor gave a negative response in rat liver UDS assays when tested at the acute MTD, gavage administration of a single, supra-MTD dose (2000 mg/kg) gave a weak positive assay response. This dose-level (2000 mg/kg) was necrotic to the liver, depressed hepatic glutathione levels by up to approximately 80%, altered the metabolism of acetochlor, and was associated with up to 33% lethality. In contrast, reference liver genotoxins such as DMN, DMH and 2AAF were shown to elicit UDS in the absence of such effects, and at approximately 400 x lower dose-levels. Finally, microscopic nasal polypoid adenomas were induced in the rat when acetochlor was administered for two years at the maximum tolerated dose (MTD). The tumours were not life-threatening, they did not metastasize, and no DNA damage was induced in the nasal cells of rats maintained on a diet containing the MTD of acetochlor for either 1 or 18 weeks (comet assay). In order to probe the mechanism of action of these high dose toxicities a series of chemical and genetic toxicity studies was conducted on acetochlor and a range of structural analogues. These revealed the chloroacetyl substructure to be the clastogenic species in vitro. Although relatively inert, this substituent is preferentially reactive to sulphydryl groupings, most evidently, to glutathione (GSH). Similar chemical reactivity and clastogenicity in vitro was observed for two related chemicals bearing a chloroacetyl group, both of which have been defined as non-carcinogens in studies reported by the US.NTP. These collective observations indicate that the source of the clastogenicity of acetochlor in vitro is also the source of its rapid detoxification in the rat in vivo, via reaction with GSH. Metabolic studies of acetochlor are described which reveal the formation of a series of GSH-associated biliary metabolites in the rat that were not produced in the mouse. The metabolism of acetochlor in the rat changes with increasing dose-levels, probably because of depletion of hepatic GSH. It is most likely that a rat-specific metabolite is responsible for the rat nasal tumours observed uniquely at elevated dose-levels. The absence of genetic toxicity to the nasal epithelium of rats exposed acutely or subchronically to acetochlor favours a non-genotoxic mechanism for the induction of these adenomas. The observation of a time- and dose-related increase in S-phase cells in the nasal epithelium is consistent with this conclusion. Despite some confusion caused by the early use of perilethal gavage administrations of acetochlor to rodents, and supra-MTD dietary concentrations in some of the chronic studies, the available MTD data are consistent with acetochlor not posing a genetic or carcinogenic hazard to humans.

[Effect of rapeseed from different distributors on the rat liver]. / Efecto de la semilla de nabo de diferentes proveedores sobre el hígado de la rata.

In previous papers it was reported that rapeseed could prevent the development of cirrhosis induced by carbon tetrachloride and at the same time can induce liver regeneration in the rat. In such experiments rapeseed was always obtained from the same distributor "Semillas Berentsen". When reseed of different distributors was used, neither cirrhosis prevention or liver regeneration was observed. The difference among the rapeseed used was that "Semillas Berentsen" utilizes a fungicide to preserve the seed and the other distributors do not use any preservative. This circumstance made think that the active principle responsible for the effects observed is probably the fungicide.

A new surgical procedure consisting of ligation of the common hepatic artery and auto-transplantation of hepatocytes into the spleen for end stage liver cirrhosis accompanied by ascites.

The authors developed a new surgical procedure for end stage liver cirrhosis associated with ascites. This procedure consists of ligation of the common hepatic artery and hepatocyte inoculation into the spleen (method A) and in this study is compared with common hepatic artery ligation alone (method B). Six of the eleven dogs operated by method A survived for six months or more with a significant (P < 0.01) difference in the three month survival in comparison with method B. In the hemodynamic study of both methods, the portal vein pressure and portal resistance decreased as a result of operation, but in method B, they returned to preoperative levels and in method A the low levels persisted for more than one year. In our method, liver function improved remarkably after three months. The hepaplastin and the cholinesterase levels increased after three months in method A with a significant difference (P < 0.01) in comparison with method B. The labeling index (L.I.) of intrasplenic hepatocytes also increased three months later. We emphasize that our method is an ideal procedure not only to improve portal haemodynamics but also to improve liver function, in end stage cirrhosis.

Somatostatin analogue improves survival in conscious cirrhotic rats subjected to gastrointestinal bleeding.

1. The continuing doubt concerning the value of vasoconstrictive therapy for gastrointestinal bleeding may be related to the complexity of clinical trials in such a situation. 2. The effect of SM 201-995, a somatostatin analogue, was investigated in conscious cirrhotic rats before, during and after experimental bleeding from the portal territory. 3. Before haemorrhage, somatostatin analogue (8 micrograms h-1 kg-1 body weight, intravenously) produced a significant decrease in portal pressure (17%), whereas a placebo (saline) lacked significant effect. 4. The rats were then subjected to spontaneous bleeding, by disconnection of the portal catheter from the pressure gauge, for a 5 min period. At the end of the haemorrhage, haemodynamic parameters did not significantly differ between the group receiving somatostatin analogue and that receiving placebo. 5. Fifteen minutes after the end of the bleeding period, portal pressure was significantly lower in rats receiving somatostatin analogue [8.5 +/- 0.5 mmHg (1.13 +/- 0.07 kPa), mean +/- SEM] than in rats receiving placebo [11.0 +/- 1.1 mmHg (1.50 +/- 0.15 kPa)]. 6. The volume of blood lost and mortality were significantly lower in the group treated with somatostatin analogue (2.3 +/- 0.1 ml/100 g body weight and 8%, respectively) than in the group receiving placebo (3.0 +/- 0.1 ml/100 g body weight and 50%, respectively). 7. These results demonstrate, in an experimental model, the beneficial effect of somatostatin analogue for the treatment of gastrointestinal bleeding due to portal hypertension. They suggest that administration of this substance should be started as soon as possible after the beginning of haemorrhage and continued after the cessation of bleeding.