Concanavalin-A as a Model for Induction of Murine Autoimmune Hepatitis: Role of TNF-α and NF-κβ During The Acute Phase

Autoimmune hepatitis (AIH) is a heterogeneous immune-mediated chronic liver disease affecting children and adults. It is important to rely on a specific animal model to study the hepatic changes and to evaluate the roles played by pro-inflammatory cytokines such as tumor necrosis factor alpha "TNF-α" and transcription factors such as nuclear factor kappa-light-chain-enhancer of activated B cells "NF-κβ" in the pathogenesis and outcome of the disease. This will help to identify specific targets for treatment of AIH. This study aimed at evaluating Concanavalin-A (Con A) as a model for induction of AIH and assessing splenocytes' TNF-α and hepatocytes' NF-κβ levels at comparable durations after induction of hepatitis with Con A to evaluate the relationship between both factors. Materials and methods: A total of 130 outbreed CD1 mice were divided into group (1) which included 100 mice with induced AIH and group (2) included 30 normal mice as negative controls. Intra-peritoneal injection of Concanavalin-A was used to induce hepatitis. Hepatic injury was evaluated by the levels of liver enzymes, histopathological evidence for hepatic inflammatory infiltrate and/or apoptosis. Splenocytes and hepatocytes were cultured for assessment of TNF-α and NF-κβ levels, respectively. Results: Con A injection caused a significant elevation in ALT and AST levels, portal inflammatory infiltrate, remarkable hepatocytes degeneration and marked increase of TNF-α levels, particularly within 24 hours, but all returned to normal within 1 week. Administration of another dose of Con A resulted in sharp significant elevation of liver enzymes, inflammatory infiltrate and hepatocyte apoptosis after 24 hours and sustained till the end of the study. There was a significant increase in NF-κβ throughout most of the study duration following Con A injection as compared to that of normal mice. In conclusions, intra-peritoneal administration of Con A, particularly two doses, represents an efficient approach for induction of immune-mediated hepatitis. T-cells play a major role in AIH through release of TNF-α. Coincidently, hepatitis seems to be associated with elevation of NF-κβ to protect hepatocytes. Thus TNF-α and NF-κβ can represent targets for treatment of AIH either through inhibition or augmentation, respectively.

Hepatoprotective effects of curcumin and taurine against bisphenol A-induced liver injury in rats

Bisphenol A (BPA) is an estrogenic endocrine disrupting chemical to which humans are frequently exposed during routine daily life. Curcumin and taurine are natural products that have also been used as antioxidants against different environmental toxin-induced hepatotoxicity. Furthermore, they have protective and therapeutic effects against various diseases. The present investigation has been conducted to evaluate the therapeutic potential of curcumin (100 mg kg^-1) and taurine (100 mg kg^-1) for their hepatoprotective efficacy against BPA (130 mg kg^-1)-induced liver injury in rat. BPA significantly elevated the levels of malondialdehyde (MDA), while it reduced the activities of catalase (CAT), total glutathione S-transferase (GST), total glutathione peroxidase (GPx), and total superoxide dismutase (SOD). Besides, these biochemical changes were accompanied by histopathological alterations marked by the destruction of normal liver structure. The histological examinations showed that exposure of BPA caused dilatation of sinusoids, inflammatory cell infiltration, congestion, and necrosis in liver parenchyma. The BPA-induced histopathological alterations in liver were minimized by curcumin and taurine treatment. Furthermore, no necrosis was observed in the liver tissues of curcumin plus BPA and taurine plus BPA-treated rats. Oral administration of curcumin and taurine to BPA-exposed rats significantly reversed the content of lipid peroxidation products, as well as enhanced the activities of GPx and GST, CAT, and SOD enzymes. These findings have indicated that curcumin and taurine might have a protective effect against BPA-induced hepatotoxicity in rats.

The anti-inflammatory influence of Cinnamomum burmannii against multi-walled carbon nanotube-induced liver injury in rats

Carbon nanotubes (CNTs) are extensively used in nanotechnology due to their unique physico-chemical properties. CNTs were implicated in many disorders connected with human health. So, we aimed in this study to provide new insight into the role of aqueous C. burmannii in treating the possible hepatotoxic effects of multi-walled carbon nanotube (MWCNTs) exposure. A total of 32 male albino rats were divided into 4 groups: control group, cinnamon-treated group, MWCNT-treated, and cinnamon- and MWCNT-treated group. To achieve the aim of this study, evaluation of percentage change of body weight, oxidant, and antioxidant status including lipid peroxidation (LPO), nitrite, total thiols, glutathione contents (GSH), the activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione-S transferase (GST) was done. Histopathological examination and the rate of pro-inflammatory cytokines including interleukin-6 (IL-6), interleukin-1β (IL-1β), cyclooxygenase-1 (COX-1), and tumor necrotic factor-α were performed. Oral administration of aqueous C. burmannii to those MWCNT-treated rats resulted in a significant reduction in LPO and total thiol contents with a significant elevation in the activities of SOD, CAT, and GPX, while GSH content and GST activity were not significantly affected. We observed a significant downregulation in the rate of previous pro-inflammatory cytokines. All this improvement in these examined markers resulted in a significant modulation in the hepatic histopathological lesions caused by MWCNTs. Aqueous C. burmannii extract exhibited a potential defensive effect on the hepatic injury triggered by MWCNTs through upgrading the antioxidant system and downregulating the rate of pro-inflammatory cytokines.

Use of Thymidine Kinase Recombinant Adenovirus and Ganciclovir Mediated Mouse Liver Preconditioning for Hepatocyte Xenotransplantation

Hepatocyte transplantation is the best approach to maintain and propagate differentiated hepatocytes from different species. Host liver has to be adapted for transplanted hepatocytes productive engraftment and proliferation being required a chronic liver injury to eliminate host hepatocytes and provide a proliferative advantage to the transplanted hepatocytes. Most valuable mouse models for xenograft hepatocyte transplantation are based on genetically modified animals to cause a chronic liver damage and to limit host hepatocyte regeneration potential. We present a methodology that generates a chronic liver damage and can be applied to any host mouse strain and animal species based on the inoculation of a recombinant adenovirus to express herpes simplex thymidine kinase in host hepatocytes sensitizing them to ganciclovir treatment. This causes a prolonged liver damage that allows hepatocyte transplantation and generation of regenerative nodules in recipient mouse liver integrated by transplanted cells and host sinusoidal. Obtained chimeric animals maintain functional chimeric nodules for several weeks, ready to be used in any study.

Carbamazepine-induced acute liver failure as part of the DRESS syndrome

Carbamazepine is a widely used drug. It is commonly associated with hepatic abnormalities, ranging from an asymptomatic rise in liver function tests to acute liver failure. The most severe reaction occurs as part of a generalised hypersensitivity reaction, also known as drug reaction, eosinophilia and systemic symptoms (DRESS). We describe a case of a young adult who presented with non-specific symptoms, which progressed to fulminant hepatic failure, displaying the hallmarks of DRESS. We highlight the need for awareness of such an association.

Idiosyncratic liver injury: challenges and approaches

Clinical presentations of drug-induced liver injury (DILI) cover essentially the entire spectrum of known liver diseases. However, in the last 8 years the form of liver injury that has most frequently resulted in labeling restrictions is idiosyncratic hepatocellular injury leading to acute liver failure. This rare form of DILI has a characteristic clinical presentation that includes an acute onset after uneventful treatment with drug for weeks to months. Serum alanine aminotransferase rises to very high levels and the appearance of jaundice indicates a high mortality even if the therapy is discontinued. Drugs that can cause this type of injury almost always are associated with frequent (2-15% of all treated patients) and minor serum aminotransferase elevations. These elevations are believed to reflect true liver injury, but often reverse even if drug therapy is continued. The bases for this "adaptation" is not known, as is why some patients do not adapt and develop progressive liver injury. Understanding how drugs cause severe idiosyncratic hepatocellular toxicity has been frustrated by the lack of good preclinical models. Indeed, because these events occur so rarely, the vast majority of humans are not good models. Studies of genomic DNA from affected individuals should provide important insight but not the complete answer because environmental factors almost certainly contribute to individual susceptibility. The most fruitful approach may therefore lie in focused and well-controlled phenotype/genotype studies of the rare patients who have survived this type of injury. The National Institute of Diabetes and Digestive and Kidney Diseases of The National Institutes of Health has recently sponsored a cooperative agreement (UO1) to create a Drug Induced Liver Injury Network (DILIN). DILIN consists of University of Michigan, Indiana University, University of Connecticut, University of California, San Francisco, University of North Carolina, and Duke University. This network should provide heretofore missing resources required to address the problem.

The liver in HIV in Africa

As access to antiretroviral therapy improves across the African continent, liver disease is emerging as an important cause of morbidity and mortality among HIV-infected individuals. Although coinfection with hepatitis B virus (HBV) and hepatitis C virus (HCV), along with highly active antiretroviral therapy (HAART)-induced hepatotoxicity appear to be the major causes of liver disease in this population, other diseases endemic to Africa with hepatic manifestations are influenced by HIV infection as well. In this review we present the available data on liver disease in HIV-infected populations in Africa and discuss relevant data from the rest of the world. In addition, we highlight important areas for further study.

Ramipril-associated hepatotoxicity

CONTEXT

Angiotensin-converting enzyme inhibitors are prescribed for many cardiovascular and renal diseases. Adverse hepatic events, especially cholestasis, have rarely been reported with captopril, enalapril, lisinopril, and fosinopril. To date, hepatic injury associated with ramipril has not been reported.

OBJECTIVE

To describe 3 patients who developed hepatitis, with or without jaundice, after receiving ramipril.

DESIGN

Medical records and liver biopsies of the 3 patients were reviewed. Clinical, laboratory, and histologic findings were compared with findings in other cases of angiotensin-converting enzyme inhibitor-induced liver injury reported in the literature.

RESULTS

The 3 patients were middle-aged men. In 2 patients, jaundice appeared 4 and 8 weeks after starting ramipril. Bilirubin levels peaked at 15.5 and 5 mg/dL, and alkaline phosphatase values peaked at 957 and 507 U/L. Aminotransferase levels were mildly elevated. Endoscopic retrograde cholangiopancreatography and ultrasonography showed no bile duct obstruction. Liver biopsies from the jaundiced patients were similar, with cholestasis, duct necrosis, and extravasation of bile, ductular proliferation, and portal inflammation. Cholestasis improved in 1 patient 6 weeks after stopping ramipril and was prolonged for 14 months in the other, in whom biliary cirrhosis was present on biopsy. The third patient developed hepatitis without jaundice 3 weeks after starting ramipril; symptoms resolved after stopping the drug. Ramipril-associated liver injury is similar to that seen with other angiotensin-converting enzyme inhibitors, but liver biopsy findings of duct necrosis and extravasation of bile have not been reported previously.

CONCLUSION

Prolonged cholestatic hepatitis and biliary cirrhosis may result from the use of ramipril. Monitoring of liver enzymes is advisable for patients starting on ramipril.

Minocycline-induced liver injury

Tetracycline may cause fatty infiltration of the liver; more recently, it has been reported to cause intrahepatic cholestasis with bile duct depletion. However, minocycline, a derivative of tetracycline, is not generally recognized to be hepatotoxic. We report a series of six cases of presumed minocycline-induced liver injury; five of these patients had acute hepatitic illness, whereas one had a more prolonged course with histological evidence of chronic hepatitis. In addition, three patients demonstrated abnormal anti-nuclear antibody levels, and one had positive double-stranded DNA.

Chronic active hepatitis and liver cirrhosis in association with combined tamoxifen/tegafur adjuvant therapy

Two female breast cancer patients who received combined tamoxifen and tegafur as postsurgical adjuvant therapy developed severe hepatotoxicity after being treated for three and eight months, respectively. Shortly after the cessation of the treatment, routine liver tests showed gradual recovery, but liver biopsies revealed chronic active hepatitis in one patient and liver cirrhosis in the other. Four and five years, respectively, after the cessation of the treatment, the results of liver tests were normal and distinct histological improvement was observed in both patients. Because these patients had no viral and immunoserological markers nor any history of alcohol abuse, this study suggested that the tamoxifen and tegafur regimen induced reversible chronic active liver disease.

Severe chronic active hepatitis induced by UFTR containing tegafur and uracil

A 77-year-old female patients developed severe hepatic injury after the administration of UFTR, which contains tegafur and uracil, for postoperative chemotherapy of colon cancer. Liver damage was recognized 10 months after its administration. Serum markers for viral hepatitis and various autoantibodies were negative. The wedged biopsied liver specimen revealed advanced chronic active hepatitis with periportal confluent necrosis, marked intralobular spotty necrosis, and significant proliferation of pseudo-bile ductules. Although the cessation of the drug and conservative therapies improved hepatic function, an accidental readministration of UFTR caused her severe hepatic damage again. These findings suggest that liver injury in the present case was caused by UFTR. Histological findings were unique. Although tegafur is known to worsen hepatic function when given to patients with liver cirrhosis, UFTR may also cause severe hepatic injury in those without preexisting liver disease.

Severe hepatotoxicity related to benzarone: a report of three cases with two fatalities

We report three cases of severe hepatotoxicity related to benzarone, a benzofuran derivative. Our cases include a 35-year-old woman with (sub)fulminant hepatitis, a 67-year-old woman with macronodular cirrhosis, and a 68-year-old man with severe chronic active hepatitis and cirrhosis, with positivity of anti-smooth muscle antibodies. Two patients died. We stress the potential of benzarone to cause hepatotoxicity, which usually resembles severe chronic active hepatitis. Our cases constitute the most severe cases of benzarone hepatotoxicity reported so far, and comprise the first cases of (sub)fulminant hepatitis and cirrhosis related to benzarone.

[Interferon or C virus-induced autoimmune chronic hepatitis? Report of personal observations and review of the literature]

Chronic persistent hepatitis C in a 35 year-old man treated for nine months with interferon, converted into autoimmune chronic hepatitis. Prior to this conversion, the laboratory cell-integrity parameters of C hepatitis had permanently returned to normal, and HCV RNA had become negative. Prior to the initiation of treatment with interferon, no autoimmune antibodies had been present. On the basis of reports in the literature, the possible pathogenesis of this conversion is discussed, with two major mechanisms being considered: 1. induction of the autoimmune process by interferon, and 2. the "unmasking" of a pre-existing autoimmune process in the later course of chronic virus C hepatitis.

Retinoid hepatitis

A 65-year-old woman treated with etretinate for pityriasis rubra pilaris developed chronic active hepatitis. The elevated transaminases were noted 2 months after initiation of therapy and peaked 2 months after discontinuation of etretinate. The spectrum of liver toxicity induced by etretinate is reviewed. We suggest that reported cases of retinoid-induced liver disease can be divided into four distinct categories: nonspecific reactive hepatitis, acute hepatitis, chronic active hepatitis, and severe fibrosis or cirrhosis.

Diclofenac induced hepatitis. 3 cases with features of autoimmune chronic active hepatitis

Diclofenac is a frequently prescribed nonsteroidal antiinflammatory drug (NSAID). Significant hepatotoxicity related to diclofenac may be more common than previously recognized, as three patients with diclofenac-associated hepatitis were seen by one clinician in a single year. All patients were ANA positive during the hepatitis and had histologic features of chronic active hepatitis. Two had been inappropriately treated with corticosteroids. The third patient presented more acutely with jaundice and symptoms of hepatitis. Two of the patients developed the same hepatic reaction when rechallenged with diclofenac. The third patient was changed to tiaprofenic acid, a NSAID of the same family, and redeveloped evidence of hepatotoxicity. All three were subsequently able to take naproxen without liver dysfunction. Diclofenac-induced liver disease may be misdiagnosed. Twenty-six cases of significant hepatic reactions to diclofenac have been previously reported in the literature and are reviewed. Such hepatic reactions to diclofenac and related NSAIDs may be commoner than realized. Introduction of a NSAID of another class appears to be safe.

Phenytoin-induced chronic hepatitis

Phenytoin has been associated with acute hepatotoxicity. Chronic liver enzyme abnormalities associated with phenytoin have been attributed to enzyme induction. There have been no reports of phenytoin-induced chronic hepatitis. We describe an asymptomatic 52-year-old woman who received phenytoin sodium for 11 years and was found to have elevated serum aminotransferases. Assays for hepatitis A, B, and C were negative. Liver biopsy was performed and showed chronic persistent hepatitis. This documentation of phenytoin-induced chronic persistent hepatitis was proven by histology and its etiology confirmed by drug withdrawal and by rechallenge. Although uncommon, this entity is important to recognize in the differential diagnosis of asymptomatic chronic hepatic enzyme dysfunction.

A fatal case of neuroleptic malignant syndrome

A fatal case of Neuroleptic Malignant Syndrome (NMS) affecting a middle-aged woman is presented. Most of the signs and symptoms described for NMS were present and death occurred three hours after the onset of hyperpyrexia. Laboratory and postmortem findings were non-specific. The uses and risks of Haloperidol and Phenelzine on a patient with severe liver impairment are considered. Finally, the medico-legal implications in the context of sudden unexpected death are mentioned.