Prophylaxis against lipopolysaccharide-induced liver injuries by lipoic acid in rats

Lipopolysaccharide (LPS) is a major cell wall molecule of Gram-negative bacteria known to stimulate the synthesis and secretion of several metabolites, such as reactive oxygen species, from phagocytes that play an important role in the pathogenesis of tissue injuries. In this study, the prophylactic effect of the antioxidant lipoic acid was evaluated in an animal acute organ injury model. Animals were pre-treated intraperitoneally with lipoic acid (50 mg kg(-1) body weight) or saline; 3 h later, pretreated animals were challenged intravenously with LPS (Escherichia coli 0111:B4, 1.0 mg kg(-1) body weight) or saline and killed 21 h later. Saline-pretreated animals challenged with LPS were extensively damaged in the liver, as evidenced by an increase in plasma alanine and aspartate aminotransferase activities. Also, LPS injection to saline-pretreated animals resulted in significant increases in plasma tumour necrosis factor-alpha (TNFalpha) and nitric oxide (NO) concentrations, suggestive of activation of the proinflammatory response. The LPS challenge to saline-pretreated animals also increased hepatic myeloperoxidase activity as well as protease and chloramine levels, suggestive of neutrophil infiltration and activation of the inflammatory response. In addition, the involvement of oxidative stress was evident, because a significant increase in lipid peroxidation was observed in the livers of saline-pretreated animals challenged with LPS. The administration of lipoic acid prior to LPS challenge resulted in a significant alleviation of liver injuries, evidenced by a general reversal of the altered biochemical indices toward normal among treated animals. These results indicate that lipoic acid may serve as a potentially effective prophylactic pharmacological agent in alleviating LPS-induced tissue injuries.

Neurokinin-1 Receptor Antagonists Protect Mice from CD95- and Tumor Necrosis Factor-α-Mediated Apoptotic Liver Damage

Previously, we have shown that primary afferent neurons are necessary for disease activity in immune-mediated liver injury in mice. These nerve fibers are detectable by substance P (SP) immunocytochemistry in the portal tract of rodent liver. Antagonists of the neurokinin-1 receptor (NK-1R), which is the prime receptor of SP, prevented liver damage by suppressing the synthesis of proinflammatory cytokines. Here, we investigated the influence of primary afferent nerve fibers, SP, and NK-1 receptor antagonists on hepatocyte apoptosis in vivo induced by administration of activating anti-CD95 monoclonal antibody (mAb) to mice. Depletion of primary afferent nerve fibers by neonatal capsaicin treatment prevented CD95-mediated activation of caspase-3, measured as enzymatic activity in liver homogenates or by demonstration of hepatocellular immunoreactivity for active caspase-3 in liver slices, and liver damage. This effect was reversed by administration of SP to anti-CD95 mAb-treated mice depleted from primary afferent neurons. The presence of the NK-1R on mouse hepatocytes was demonstrated by immunocytochemistry and flow cytometry. Intraperitoneal pretreatment with the NK-1 receptor antagonists (2S,3S)-cis-2-(diphenylmethyl)-N-([2-methoxyphenyl]-methyl)-1-azabicyclo(2.2.2.)-octan-3-amine (CP-96,345) or (2S,3S)3-([3,5-bis(trifluoromethyl)phenyl]methoxy)-2-phenylpiperadine (L-733,060) dose dependently protected mice from CD95-mediated liver injury. Similar results were obtained when apoptotic liver damage was induced by administration of tumor necrosis factor-alpha to d-galactosamine-sensitized mice. In conclusion, SP, probably by binding to its receptor on hepatocytes, might aggravate apoptotic signals in these cells. Because NK-1 receptor antagonists not only suppress the proinflammatory cytokine response in the liver but also prevent liver cell apoptosis in vivo, they might be suitable drugs for treatment of immune-mediated liver disease.

[D-Ala2, D-Leu5] enkephalin (DADLE) protects liver against ischemia-reperfusion injury in the rat

BACKGROUND

[D-Ala(2), D-Leu(5)] enkephalin (DADLE) is a synthetic delta class of opioid and is reported to induce hibernation as well as hibernation induction trigger (HIT) in the serum of hibernating mammals. DADLE and HIT have been demonstrated to protect the heart, lung, and jejunum against ischemia-reperfusion (I-R) injury. In the present study, we examined the effect of DADLE on I-R injury of the liver in rats.

METHODS

After administration of DADLE (DADLE group) or normal saline as a vehicle (Control group), partial hepatic ischemia was induced by occluding the vessels supplying 92% of the liver for 45 min, followed by declamping the vessels and resection of the non-ischemic lobe. After 120 min of reperfusion, serum glutamic-pyruvic transaminase (GPT), hyaluronic acid (HA) levels, and concentrations of malondialdehyde (MDA) of the liver tissue were measured. Additionally, bile output from the ischemic lobes was measured after reperfusion.

RESULTS

GPT levels were significantly lower in the DADLE group as compared to those of the Control group (P < 0.05), but the serum levels of HA were not different between the two groups. The concentrations of MDA of the liver tissue were significantly lower in the DADLE group than in the Control group (P < 0.01). The bile output after reperfusion was not significantly different between the two groups.

CONCLUSIONS

DADLE protects against I-R injury in hepatocytes, but not in the sinusoidal endothelial cells of the liver in rats. An anti-oxidative effect is suggested to be responsible for this effect.

S-adenosylmethionine (AdoMet) supplementation for treatment of chemotherapy-induced liver injury

BACKGROUND

Liver toxicity can be observed during treatment with most chemotherapic agents, and represents one of the principal causes of dose reduction or chemotherapy delays. S-Adenosylmethionine (AdoMet) plays a critical role in the synthesis of polyamines and provides cysteine for the production of glutathione (GSH), the major endogenous hepatoprotective agent. Our study was aimed at assessing the protective effect of AdoMet supplementation in cancer chemotherapy-induced liver toxicity.

PATIENTS AND METHODS

Fifty cancer patients who developed, for the first time, anticancer chemotherapy-induced liver toxicity were studied. Enrolled patients received oral AdoMet supplementation.

RESULTS

AST, ALT and LDH levels recorded at the moment of the recognition of liver toxicity were significantly reduced after one week of AdoMet therapy (respectively p: 0.009, 0.0005 and 0.012). AST, ALT and LDH decrease was confirmed after two weeks of treatment. Furthermore, the effect on these enzyme levels persisted in the following chemotherapy courses, permitting our patients to perform the scheduled chemotherapy courses with a minimal number of dose reductions or administration delays. The efficacy of AdoMet supplementation was not influenced by the presence of liver metastases, and no appreciable side-effects were recognized.

CONCLUSION

The results of our study clearly demonstrate a protective effect of AdoMet in cancer chemotherapy-induced liver toxicity. Further large phase III studies are required to assess the real clinical benefit associated with AdoMet supplementation.

Effect of N-acetylcysteine on acetaminophen toxicity in mice: relationship to reactive nitrogen and cytokine formation

The relationship between acetaminophen (APAP) reactive metabolite formation, nitrotyrosine (NT) production, and cytokine elevation in APAP toxicity was investigated. Mice were dosed with 300 mg/kg of APAP and sacrificed at 1, 2, 4, 8, and 12 h. Serum aspartate aminotransferase (AST) was elevated by 4 h. The relative amount of NT correlated with toxicity and was localized in the necrotic cells. IL-1b was increased at 1 h, whereas IL-6, MIP-2, and MCP-1 were increased by 4-8 h. To determine the importance of reversible versus toxic events, N-acetylcysteine (NAC) was administered to mice either before APAP or 1, 2, or 4 h after APAP. The animals were sacrificed at 12 h. NAC treatment before APAP resulted in serum AST, serum nitrate plus nitrite as a measure of nitric oxide (NO) production, and hepatic cytokine levels that were similar to the controls. No APAP protein adducts or NT was present in these animals. In mice treated with NAC at 1 h, cytokines and serum AST were normal at 12 h, but APAP protein adducts were present in the hepatic centrilobular areas. No NT was present in these animals. In mice treated with NAC at 2 h and sacrificed at 12 h, serum AST was reduced by 80%. APAP adducts and NT were present in the centrilobular areas. Mice receiving NAC at 4 h had no protection from toxicity and serum nitrate plus nitrite. The NT and cytokine levels were similar to those of mice receiving APAP alone. The data suggest a relationship between metabolic events in APAP toxicity and the upregulation of NO, and IL-1b. IL-6, MIP-2, and MCP-1 appear to follow the toxicity. While it is a pre-requisite event, covalent binding per se does not appear to be a toxic event in the development of toxicity.

Mitigation of pennyroyal oil hepatotoxicity in the mouse

OBJECTIVES

Pennyroyal oil ingestion has been associated with severe hepatotoxicity and death. The primary constituent, R-(+)-pulegone, is metabolized via hepatic cytochrome P450 to toxic intermediates. The purpose of this study was to assess the ability of the specific cytochrome P450 inhibitors disulfiram and cimetidine to mitigate hepatotoxicity in mice exposed to toxic levels of R-(+)-pulegone.

METHODS

20-g female BALB/c mice were pretreated with either 150 mg/kg of cimetidine intraperitoneal (IP), 100 mg/kg of disulfiram IP, or both. After one hour, mice were administered 300 mg/kg of pulegone IP and were killed 24 hours later. Data were analyzed using ANOVA. Post-hoc t-tests used Bonferroni correction.

RESULTS

There was a tendency for lower serum glutamate pyruvate transaminase in the disulfiram and cimetidine groups compared with the R-(+)-pulegone group. The differences were significant for both the cimetidine and the combined disulfram and cimetidine groups compared with the R-(+)-pulegone group. Pretreatment with the combination of disulfiram and cimetidine most effectively mitigated R-(+)-pulegone-induced hepatotoxicity.

CONCLUSIONS

Within the limitations of a pretreatment animal model, the combination of cimetidine and disulfiram significantly mitigates the effects of pennyroyal toxicity and does so more effectively than either agent alone. These data suggest that R-(+)-pulegone metabolism through CYP1A2 appears to be more important in the development of a hepatotoxic metabolite than does metabolism via CYP2E1.

Protective effect of low molecular weight heparin on oxidative injury and cellular abnormalities in adriamycin-induced cardiac and hepatic toxicity

The aim of the present work is to evaluate the effect of a heparin derivative, low molecular weight heparin (LMWH) on the biochemical changes, tissue peroxidative damage and abnormal antioxidant levels in adriamycin (ADR) induced cardiac and hepatic toxicity. Male Wistar rats (140 +/- 10 g) were divided into four groups: untreated control (group I), ADR group (a single dose intravenous injection of 7.5 mg/kg ADR--group II), LMWH control (300 microg/day per rat s.c. for 1 week--group III) and ADR plus LMWH group (7.5 mg/kg ADR on day 1 of study period followed by LMWH treatment, 300 microg/day per rat commencing on day 8 and continued for a week. At the end of the 2-week experimental period, all animals were terminated. Cellular damage was assessed in terms of serum and tissue lactate dehydrogenase (LDH), aminotransferases and alkaline phosphatase (ALP) activities. Creatine phosphokinase (CPK) was assessed in the serum and heart tissue. The role of LMWH in altering the oxidative stress in ADR-induced toxicity was evaluated on the basis of its influence on cardiac and hepatic lipid peroxidation and antioxidant status (enzymatic and non-enzymatic)--superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx), reduced glutathione (GSH), alpha-tocopherol (Vitamin E) and ascorbate (Vitamin C). LMWH administration to ADR-induced rats prevented the rise in serum and tissue levels of LDH, aminotransferases and ALP, while these parameters were significantly elevated in the ADR group in comparison with the control group. Cardiotoxicity indicated by rise in serum CPK in the ADR group was attenuated by LMWH treatment in group IV. LMWH decreased the cardiac and hepatic lipid peroxidation induced by ADR. Histologic examination revealed that the ADR-induced deleterious changes in the heart and liver tissues were offset by LMWH treatment. Restoration of cellular normalcy accredits LMWH with cytoprotective role in adriamycin-induced cardiac and hepatic toxicity.

Complete protection by high-dose dexamethasone against the hepatotoxicity of the novel antitumor drug yondelis (ET-743) in the rat

Yondelis (ET-743) is a promising antitumor drug with hepatotoxic properties in animals and humans. Here the hypothesis was tested that dexamethasone can ameliorate manifestations of yondelis-induced hepatotoxicity in the female Wistar rat, which is the animal species with the highest sensitivity toward the adverse hepatic effect of yondelis. Hepatotoxicity was adjudged by measurement of plasma levels of alkaline phosphatase, aspartate aminotransferase, and bilirubin, and by liver histopathology. Yondelis (40 micro g/kg i.v.) alone caused a dramatic elevation of plasma alkaline phosphatase, aspartate aminotransferase, and bilirubin levels, and degeneration and patchy focal necrosis of bile duct epithelial cells. Pretreatment of rats with dexamethasone (5-20 mg/kg, p.o.) 24 h before yondelis ameliorated or abrogated the biochemical and histopathological manifestations of yondelis-induced liver changes. In contrast, when dexamethasone was administered simultaneously with yondelis, its toxicity was not reduced. Pretreatment with dexamethasone (10 mg/kg) also reversed the gene expression changes induced by yondelis in rat liver. However, dexamethasone pretreatment did not interfere with the antitumor efficacy of yondelis in rats bearing the 13762 mammary carcinoma or in four murine models. Dexamethasone (10 mg/kg) administered 24 h before yondelis decreased hepatic levels of yondelis dramatically compared with those obtained after administration of yondelis alone, whereas yondelis plasma levels after the drug combination were not markedly different from those in rats on yondelis alone. The results suggest that pretreatment with high-dose dexamethasone effectively protects rats against yondelis-mediated hepatic damage by decreasing hepatic exposure to yondelis, perhaps linked to induction of metabolism by cytochrome P450 enzymes. Pretreatment with high-dose dexamethasone should be investigated in patients who receive yondelis to ameliorate its unwanted effect on the liver.

Suppression of ethanol and lipopolysaccharide-induced liver injury by extracts of Hydrangeae Dulcis Folium in rats

In female SD rats that were injected with 4 g/kg BW ethanol p.o. followed by a 5 mg/kg BW lipopolysaccharide (LPS) i.v. injection, serum glutamic pyruvic transaminases (GPT) activity increased to about eight times that of normal rats. In this model, rats that had been fed a diet containing 1% Hydrangeae Dulcis Folium (HDF) extracts for fifteen days showed significantly lower serum GPT activity (380.0+/-58.2 IU/l) than the control group (3527.0+/-774.1 IU/l). HDF's efficacy was far superior to milk thistle in this model (2950.0+/-915.9 IU/l). When mouse macrophages were treated with HDF extracts at 50 microg/ml, TNF-alpha production induced by LPS was suppressed to about 10% of the control. Rat serum TNF-alpha levels induced by LPS was decreased to 58.7% of the control by administering 1000 mg/kg BW HDF extract p.o. These results indicate that HDF prevents alcohol-induced liver injury through the inhibition of TNF-alpha production.

Silibinin protects mice from T cell-dependent liver injury

BACKGROUND/AIMS

Silibinin is the major pharmacologically active compound of the Silybum marianum fruit extract silymarin. Its well-known hepatoprotective activities are mostly explained by antioxidative properties, inhibition of phosphatidylcholine synthesis or stimulation of hepatic RNA and protein synthesis. Here, we characterized the hepatoprotective potential of silibinin as an immune-response modifier in T cell-dependent hepatitis in vivo.

METHODS

Silibinin was tested in the mouse model of concanavalin A (ConA)-induced, T cell-dependent hepatitis. Liver injury was assessed by quantification of plasma transaminase activities and intrahepatic DNA fragmentation. Plasma cytokine concentrations were determined by enzyme-linked immunosorbent assay (ELISA), intrahepatic cytokine and inducible NO synthase (iNOS) mRNA levels by reverse transcriptase polymerase chain reaction, intrahepatic iNOS expression by immunofluorescent staining, and intrahepatic nuclear factor kappa B (NF-kappaB) activation by electrophoretic mobility shift assay.

RESULTS

Silibinin significantly inhibited ConA-induced liver disease. Silibinin proved to be an immune-response modifier in vivo, inhibiting intrahepatic expression of tumor necrosis factor, interferon-gamma, interleukin (IL)-4, IL-2, and iNOS, and augmenting synthesis of IL-10. In addition, silibinin inhibited intrahepatic activation of NF-kappaB.

CONCLUSIONS

Silibinin, suppressing T cell-dependent liver injury as an immune-response modifier, might be a valuable drug in therapeutic situations in which intrahepatic immunosuppression is required.

Heavy chain ferritin acts as an antiapoptotic gene that protects livers from ischemia reperfusion injury

Heme oxygenase-1 (HO-1) is induced under a variety of pro-oxidant conditions such as those associated with ischemia-reperfusion injury (IRI) of transplanted organs. HO-1 cleaves the heme porphyrin ring releasing Fe2+, which induces the expression of the Fe2+ sequestering protein ferritin. By limiting the ability of Fe2+ to participate in the generation of free radicals through the Fenton reaction, ferritin acts as an anti-oxidant. We have previously shown that HO-1 protects transplanted organs from IRI. We have linked this protective effect with the anti-apoptotic action of HO-1. Whether the iron-binding properties of ferritin contributed to the protective effect of HO-1 was not clear. We now report that recombinant adenovirus mediated overexpression of the ferritin heavy chain (H-ferritin) gene protects rat livers from IRI and prevents hepatocellular damage upon transplantation into syngeneic recipients. The protective effect of H-ferritin is associated with the inhibition of endothelial cell and hepatocyte apoptosis in vivo. H-ferritin protects cultured endothelial cells from apoptosis induced by a variety of stimuli. These findings unveil the anti-apoptotic function of H-ferritin and suggest that H-ferritin can be used in a therapeutic manner to prevent liver IRI and thus maximize the organ donor pool used for transplantation.

Melatonin protects rat liver against irradiation-induced oxidative injury

The aim of this study was to investigate the antioxidant roles of different doses of melatonin (5 and 10 mg x kg (-1) ) against gamma-irradiation-caused oxidative damage in liver tissue after total body irradiation (TBI) with a single dose of 6.0 Gy. Fifty adult rats were divided into 5 equal groups, 10 rats each. Groups I and II were injected with 5 and 10 mg x kg (-1) of melatonin, and group III was injected with an isotonic NaCl solution. Group IV was injected with only 5 mg x kg (-1) of melatonin. Group V was reserved as a sham control. Following a 30-min-period, 6.0 Gy TBI was given to groups 1, 2 and 3 in a single fraction. The liver malondialdehyde (MDA) levels, super oxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities were measured in all groups. TBI resulted in a significant increase in the liver tissue MDA levels and a decrease of SOD and GSH-Px activities. The results demonstrated that the liver tissue MDA levels in irradiated rats that were pretreated with melatonin (5 or 10 mg x kg (-1) ) were significantly decreased, while the SOD and GSH-Px activities were significantly increased. Decreasing the MDA levels by melatonin was dose dependent, but the liver tissue SOD and GSH activities were not. The data obtained in this study suggest that melatonin administration prior to irradiation may prevent liver damage by irradiation.

Protective effect of polyunsaturated phosphatidylcholine on liver damage induced by biliary obstruction in rats

BACKGROUND/PURPOSE

Persistent inflammatory response secondary to congenital or acquired biliary choleastasis plays an important role in the pathophysiology of hepatic tissue damage. The polyunsaturated fatty acids (PUFA) have been shown to suppress the inflammatory reactions in vivo and in vitro. PUFA has been shown also to protect against various types of experimental liver damage in animal models and isolated hepatocytes. Therefore, the aim of this study was to investigate the protective effect of PUFA administration on liver damage using the rat chronic biliary obstruction model.

METHODS

Swiss albino rats of either sex were divided into 4 groups as follows: control group (group 1, 10 rats); rats with sham operation and treated with saline group 2, 10 rats); rats with biliary obstruction (group 3, 15 rats); and polyunsaturated phophatidylcholine (PPC)-treated rats with biliary obstruction (Group 4, 15 rats). Biliary obstruction was induced by double ligation and division of the common bile duct. PUFA treatment was started 2 weeks later from biliary obstruction in doses of 50 mg/d per rat and continued for 2 weeks. All animals were killed after 4 weeks of common bile duct ligation or sham operation. Liver damage and cholestasis were determined by biochemical and histologic examinations.

RESULTS

The data showed a decrease in plasma bilirubin level (both conjugated and unconjugated) and liver enzyme levels (AST, ALT, AP, GGT, 5'-NT) in group 4, when compared with group 3 (P <.05). Tissue levels of malondialdehyde (MDA) in group 4 was 20.00 +/- 2.93 compared with that in group 3, 27.12 +/- 2.96 (P <.05). Administration of PUFA to the biliary obstructed rats resulted in inhibition of collagen accumulation (P <.05) and ductal proliferation (P <.05).

CONCLUSIONS

PUFA reduced liver damage, ductular proliferation, and fibrosis in biliary obstructed rats. These effects suggest that it might be a useful agent to preserve liver function in patients with biliary obstruction such as biliary atresia.

The PPAR-gamma ligand 15-deoxy(delta12,14) prostaglandin J2 reduces the liver injury in endotoxic shock

We demonstrate here for the first time that the endogenous cyclopentenone prostaglandin 15-deoxy-Delta12,14-prostaglandin J2 (15d-prostaglandin J2) reduces the liver injury (rise in serum transaminases) caused by severe endotoxaemia (6 mg/kg Escherichia coli endotoxin i.v. for 6 h) in the anaesthetised rat. The protection of the liver afforded by this potent agonist of PPAR-gamma was not secondary to a haemodynamic effect. Thus, 15d-prostaglandin J2 and other PPAR-gamma agonists may be useful in the therapy of septic shock.

Silymarin and vitamin E reduce amiodarone-induced lysosomal phospholipidosis in rats

Several antioxidants have been shown to reduce lysosomal phospholipidosis, which is a potential mechanism of amiodarone toxicity, and prevent amiodarone toxicity by antioxidant and/or non-antioxidant mechanisms. The aim of this study was to test whether the co-administration of two structurally different antioxidants vitamin E and silymarin with amiodarone can reduce amiodarone-induced lysosomal phospholipidosis, and if yes, by reducing the tissue concentration of amiodarone and desethylamiodarone or by their antioxidant action. To this end, male Fischer 344 rats were treated by gavage once a day for 3 weeks and randomly assigned to the following four experimental groups: 1, control; 2, amiodarone (150 mg/(kg per day)); 3, amiodarone (150 mg/(kg per day)) plus vitamin E (100 mg/(kg per day)); 4, amiodarone (150 mg/(kg per day)) plus silymarin (60 mg/(kg per day)) treated groups. Total plasma phospholipid (PL), liver-conjugated diene, thiobarbituric acid reactive substances (TBARSs), amiodarone and desethylamiodarone concentrations were determined and the extent of lysosomal phospholipidosis in the liver was estimated by a semi-quantitative electron microscopic method. Amiodarone treatment increased significantly the liver-conjugated diene (P<0.001), TBARS (P=0.012), plasma total PL (P<0.001) concentrations compared with control. Antioxidants combined with amiodarone significantly decreased the liver-conjugated diene (P<0.001 for both), TBARS (P=0.016 for vitamin E, P=0.053 borderline for silymarin) and plasma total PL (P=0.058 borderline for vitamin E, P<0.01 for silymarin) concentrations compared with amiodarone treatment alone. Silymarin significantly (P=0.021) reduced liver amiodarone, but only tended to decrease desethylamiodarone concentration; however, vitamin E failed to do so. Amiodarone treatment increased lysosomal phospholipidosis (P<0.001) estimated by semi-quantitative electron microscopic method and both antioxidants combined with amiodarone reduced significantly (P<0.001 for both) the amiodarone-induced lysosomal phospholipidosis. In conclusion, silymarin presumably reduced lysosomal phospholipidosis by both antioxidant action and its liver amiodarone concentration decreasing effect, while vitamin E exerted similar effect by antioxidant action alone. Thus, both antioxidant action and inhibition of tissue uptake of amiodarone might have an important role in the preventative effect of antioxidants against amiodarone toxicity.

Acetaminophen intoxication and length of treatment: how long is long enough?

The currently recommended dosing scheme for treating acetaminophen overdose in the United States consists of a loading dose of oral N-acetylcysteine 140 mg/kg, followed by 70 mg/kg every 4 hours for 17 doses, for a total of 72 hours of oral N-acetylcysteine therapy. This protocol has been both effective and safe. We critically evaluated the evidence that supports reducing the course of N-acetylcysteine therapy from 72 hours to 24 or 36 hours. This shorter regimen offers important benefits for both the patient and the patient's family, such as increased drug tolerability and reduced hospital stay. Patients who intentionally ingested acetaminophen with harmful intent could receive appropriate psychosocial treatment more quickly. In addition, shorter courses of N-acetylcysteine therapy have positive financial ramifications by reducing the hospital stay by 1 or 2 days. Clearly, a shorter treatment regimen would not be appropriate for all patients, particularly those who seek treatment late (> 24 hrs after ingestion) and those with evidence of organ toxicity. In order to provide the necessary evidence to support a change in accepted clinical practice, further investigation on the safety and efficacy of a shorter N-acetylcysteine regimen should be conducted by clinical researchers in a controlled manner.

Glycine modulates cytokine secretion, inhibits hepatic damage and improves survival in a model of endotoxemia in mice

BACKGROUND AND AIM

There is substantial experimental evidence that the amino acid glycine may have a role in protecting tissues against insults such as ischemia, hypoxia and reperfusion. Our aim was to investigate the ability of the amino acid glycine to prevent hepatic damage induced by injection of lipopolysaccharide and d-galactosamine (d-Gal), to modulate pro- and anti-inflammatory cytokine levels, and to improve survival.

METHODS

Mice were challenged with an intraperitoneal injection of d-Gal (16 mg/mouse) and lipopolysaccharide (LPS, 1 microg/mouse). The intervention group also received an intraperitoneal injection of glycine (150 mg/kg) in two doses: 24 h before and just after LPS challenge. Serum cytokine levels were measured 2 h after challenge, and liver enzymes and histology were determined 16 h after LPS. Separate groups of mice received the same treatment and the survival rate was determined 24 h and ten days after endotoxin administration. In in vitro experiments, cultured mononuclear cells were stimulated by LPS, and TNF-alpha and IL-10 secretion were measured, in the presence or absence of glycine.

RESULTS

In the glycine-treated mice, the serum levels of liver enzymes and TNF-alpha, the histologic necroinflammation score and the mortality rate were significantly reduced compared to control mice (P<0.001). Serum IL-10 levels in the glycine-treated mice were increased (P<0.01). In vitro studies in cultured lymphocytes isolated from either normal or glycine pretreated mice, demonstrated a significant and dose-dependent inhibition of LPS-induced TNF-alpha secretion and increase in IL-10 response after treatment with glycine (P<0.01). In conclusion, glycine reduces hepatic damage and improves survival rate in this mouse model of endotoxemia. The protective effect of glycine is associated with modulation of TNF-alpha and IL-10 secretion.

Role of ischemic preconditioning and the portosystemic shunt in the prevention of liver and lung damage after rat liver transplantation

BACKGROUND

This study evaluates whether surgical strategies such as the portosystemic shunt and ischemic preconditioning can protect against hepatic and pulmonary injury associated with liver transplantation.

METHODS

The effect of the portosystemic shunt, ischemic preconditioning, and both surgical procedures together were evaluated in rat liver transplantation. Alanine aminotransferase, hyaluronic acid levels in plasma, adenosine triphosphate and nucleotide levels in liver and edema, malondialdehyde levels, and myeloperoxidase activity were measured 24 hr posttransplantation. Plasmatic tumor necrosis factor (TNF) levels were measured as a possible proinflammatory factor responsible for hepatic and pulmonary damage associated with liver transplantation.

RESULTS

Hepatocyte and cell endothelial damage were observed in liver grafts subjected to 8 hr of cold ischemia. This was associated with increased plasma TNF levels and lung inflammatory response. Portosystemic shunt application in the recipient protected endothelial cells but did not confer an effective protection from hepatocyte damage or reduce the increased plasma TNF levels and lung damage after liver transplantation. However, preconditioning of the donor liver conferred protection against both the endothelial cell and hepatocyte damage observed after liver transplantation. Preconditioning also attenuated the increased plasma TNF release and pulmonary damage. The combination of both surgical strategies resulted in levels of liver injury, TNF, and lung damage similar to those seen after liver transplantation.

CONCLUSIONS

These findings indicate that ischemic preconditioning could be a preferred treatment to reduce hepatic and pulmonary damage associated with liver transplantation. However, this strategy may not be effective in several clinical situations requiring a portosystemic shunt.

Drug transporters in HIV Therapy

Drug transporter proteins play a crucial role in drug disposition. The P-glycoprotein drug efflux transporter is a determinant of oral bioavailability and central nervous system (CNS) penetration of protease inhibitors (PIs), and may affect drug penetration to other tissue compartments that can serve as sanctuaries for HIV. Potent and selective inhibitors of P-glycoprotein can dramatically increase PI CNS penetration. Polymorphisms in the MDR1 gene regulating P-glycoprotein expression are associated with differences in drug disposition, with some data indicating that different genotypes are associated with differences in plasma PI levels and magnitudes of CD4+ cell count recovery under therapy. The activity of drug transporters in modulating antiretroviral drug effects and the potential for exploiting this activity to maximize therapeutic benefit and minimize drug toxicity are the subjects of ongoing study. In addition, inhibition of transporter proteins may increase the risk of hepatotoxicity and other adverse drug effects and is being investigated. This article summarizes a presentation given by Richard B. Kim, MD, at the March 2003 International AIDS Society-USA course in Atlanta.

Clinical usefulness of edaravone for acute liver injury

BACKGROUND

Edaravone, a newly synthesized radical scavenger, has shown an excellent effect on treating stroke patients. The effect of edaravone on carbon tetrachloride (CCl4)-induced acute liver injury was examined.

METHODS

Six rats were injected with CCl4 alone and six rats were intravenously injected with edaravone immediately after and 3 h after injection of CCl4. Another six rats were injected with olive oil alone. The animals were killed at 24 h after the CCl4 injection.

RESULTS

Injection of CCl4 was followed by a marked increase in serum alanine aminotranferase (ALT) level (CCl4, 1630.6 +/- 606.8 IU/L; olive oil, 21.0 +/- 2.6 IU/L; P < 0.001), lactate dehydrogenase (LDH) level (CCl4, 5068.0 +/- 2956.4 IU/L; olive oil, 203.6 +/- 30.5 IU/L; P < 0.005), and total bilirubin (TB) level (CCl4, 0.88 +/- 0.48 mg/dL; olive oil, 0.37 +/- 0.05 mg/dL; P < 0.01), whereas in the edaravone-treated rats, the ALT (119.4 +/- 113.5 IU/L, P < 0.001), LDH (369.7 +/- 288.2 IU/L, P < 0.005), and TB values (0.29 +/- 0.16 mg/dL, P < 0.01) were significantly decreased. Histological examination of the liver by hematoxylin and eosin and oil red O staining showed a marked reduction of steatosis in the CCl4 and edaravone-treated rats compared with the CCl4-injected rats. Significant inhibition of hepatocytic apoptosis was demonstrated by the terminal deoxynucleotidyl transferase-mediated UTP nick-end labeling (TUNEL) method in the edaravone-treated rats.

CONCLUSIONS

These results suggest that edaravone has a marked preventive effect on oxidative stress-induced acute liver injury.

Utilization of hepatoprotectants within the National Health Insurance in Taiwan

BACKGROUND

Although the hepatoprotectants of Western medicine have centuries of history, their utilization patterns have been seldom documented. Because the National Health Insurance program in Taiwan reimburses hepatoprotectant use, we could estimate the age- and sex-specific prevalence and utilization patterns of hepatoprotectants in Western medicine within the health insurance system in Taiwan.

METHODS

We analyzed the outpatient prescription data of 50000 randomly sampled insured patients in 2000. Only patients using drugs indicated for liver diseases and diagnostic codes related to liver diseases on the same visit were considered to be receiving hepatoprotectants. Drugs involved in Chinese medicine were not included.

RESULTS

Among the valid cohort of 46614 people, 783 (1.7%) were identified as patients with liver disease and receiving hepatoprotectants. Highest prevalence of hepatoprotectant use was 4.9% in the 60-69 years age group. Silymarin, multivitamins, methionine, ursodeoxycholic acid, and liver hydrolysate accounted for 88.8% of the 3215 prescribed items of hepatoprotectants. Patients receiving hepatoprotectants had, on average, visited the clinics more frequently than those not using hepatoprotectants (30 vs 14 times in a year, P < 0.001), and used more insurance benefits (US dollars 1352 vs US dollars 456, P < 0.001).

CONCLUSIONS

The frequency of use of major hepatoprotectants in Taiwan corresponded to the current modalities of treatment under discussion worldwide.

Prevention by dietary (n-6) polyunsaturated phosphatidylcholines of intrahepatic cholestasis induced by cyclosporine A in animals

Previous findings showed that dietary (n-6) polyunsaturated phosphatidylcholines (vegetable lecithin) could efficiently prevent intrahepatic cholestasis induced by cyclosporine A in rats. Mechanistic studies showed that expressions in rat liver of Na(+), K(+)-ATPase, Ca(2+), Mg(2+)-ATPase and F-actin were both decreased by drug administration and both enhanced by (n-6) lecithin enriched diet. There is a possible direct effect of phosphatidylcholines, vectors of polyunsaturated fatty acids provided by the metabolism of the dietary lecithin, on the aforesaid hepatic parameters. Such modulations by drug and diet result in reversed modifications of membrane composition and fluidity. Final outcome is decreased and enhanced bile lipid secretion by cyclosporine and vegetable lecithin enriched diet respectively. Moreover, we advance the hypothesis of a bypass process including a separate and functional actin-independent way for the non micellar and phospholipid-dependent secretion of bile lipids. The relationships between the ATPases, the microfilament components such as F-actin and the different transporters still remain to be clarified. Furthermore, one can speculate on beneficial effects in humans of diets enriched in vegetable lecithins that might prevent cholestasis induced by cyclosporine A.