Cholestatic hepatocellular injury with azathioprine: a case report and review of the mechanisms of hepatotoxicity

Severe azathioprine-induced liver injury 22 months after initiation of treatment

Drug-induced liver injury (DILI) is the leading cause of acute liver failure in high-income countries. Acute cholestasis is one of the most common forms of hepatotoxicity induced by azathioprine. It usually begins during the first year of treatment, with most cases reported during the first month. We describe an uncommon case of DILI that occurred after 22 months of drug administration. A woman in her 50s was hospitalised because of jaundice and asthenia. She had been treated with azathioprine for myasthenia gravis during the last 2 years. Acute cholestatic injury was diagnosed. After ruling out most common causes of cholestasis, azathioprine was withdrawn and subsequent histological findings in liver biopsy were consistent with drug-induced cholestatic liver damage. After discontinuation of azathioprine, biochemical parameters progressively normalised and remarkable clinical improvement was achieved. With this report, we suggest that azathioprine should be considered among the causes of liver injury, despite long treatment duration.

Liver involvement in inflammatory bowel disease: What should the clinician know?

Inflammatory bowel disease (IBD) may show a wide range of extraintestinal manifestations. In this context, liver involvement is a focal point for both an adequate management of the disease and its prognosis, due to possible serious comorbidity. The association between IBD and primary sclerosing cholangitis is the most known example. This association is relevant because it implies an increased risk of both colorectal cancer and cholangiocarcinoma. Additionally, drugs such as thiopurines or biologic agents can cause drug-induced liver damage; therefore, this event should be considered when planning IBD treatment. Additionally, particular consideration should be given to the evidence that IBD patients may have concomitant chronic viral hepatitis, such as hepatitis B and hepatitis C. Chronic immunosuppressive regimens may cause a hepatitis flare or reactivation of a healthy carrier state, therefore careful monitoring of these patients is necessary. Finally, the spread of obesity has involved even IBD patients, thus increasing the risk of non-alcoholic fatty liver disease, which has already proven to be more common in IBD patients than in the non-IBD population. This phenomenon is considered an emerging issue, as it will become the leading cause of liver cirrhosis.

Common Gastrointestinal Medications Implicated in Drug-Induced Liver Injury

Content available: Author Interview and Audio Recording.

Mechanism-Driven Read-Across of Chemical Hepatotoxicants Based on Chemical Structures and Biological Data

Hepatotoxicity is a leading cause of attrition in the drug development process. Traditional preclinical and clinical studies to evaluate hepatotoxicity liabilities are expensive and time consuming. With the advent of critical advancements in high-throughput screening, there has been a rapid accumulation of in vitro toxicity data available to inform the risk assessment of new pharmaceuticals and chemicals. To this end, we curated and merged all available in vivo hepatotoxicity data obtained from the literature and public resources, which yielded a comprehensive database of 4089 compounds that includes hepatotoxicity classifications. After dividing the original database of chemicals into modeling and test sets, PubChem assay data were automatically extracted using an in-house data mining tool and clustered based on relationships between structural fragments and cellular responses in in vitro assays. The resultant PubChem assay clusters were further investigated. During the cross-validation procedure, the biological data obtained from several assay clusters exhibited high predictivity of hepatotoxicity and these assays were selected to evaluate the test set compounds. The read-across results indicated that if a new compound contained specific identified chemical fragments (ie, Molecular Initiating Event) and showed active responses in the relevant selected PubChem assays, there was potential for the chemical to be hepatotoxic in vivo. Furthermore, several mechanisms that might contribute to toxicity were derived from the modeling results including alterations in nuclear receptor signaling and inhibition of DNA repair. This modeling strategy can be further applied to the investigation of other complex chemical toxicity phenomena (eg, developmental and reproductive toxicities) as well as drug efficacy.

Hepatotoxicty of Agents Used in the Management of Inflammatory Bowel Disease: a 2020 Update

PURPOSE OF REVIEW

As treatment options for inflammatory bowel disease (IBD) continue to expand, the opportunity for hepatotoxicity remains a clinical concern. This review looks to update the current literature on drug-induced liver injury (DILI) and liver-related complications from current and emerging treatments for Crohn's disease (CD) and ulcerative colitis (UC).

RECENT FINDINGS

An extensive literature review on currently used medications to treat IBD and their liver-related side effects that includes mesalamine, thiopurines, certain antibiotics, methotrexate, anti-TNF agents including recently introduced biosimilars, anti-integrin therapy, anti-IL 12/IL 23 therapy, and small molecule JAK inhibitors. Hepatotoxicity remains an important clinical issue when managing patients with IBD. Clinicians need to remain aware of the potential for liver-related adverse events with various medication classes and adjust their clinical monitoring as appropriate based on the agents being used.

Severe cholestasis due to azathioprine in Behcet's disease

Azathioprine (AZA) is an immunosuppressive drug that is widely used in the treatment of autoimmune diseases. Although AZA is used widely, many studies reported that AZA-related hepatotoxicity is rather rare. We aimed to present a case with severe cholestatic hepatitis due to AZA use for Behcet's disease. Three weeks after starting AZA for the treatment of uveitis, the patient was admitted to our clinic with cholestasis and constitutional symptoms. In liver biopsy, findings were in accordance with drug reaction, and the AZA treatment was stopped. After 2 months, bilirubin levels and liver tests results became normal. As a result, given that AZA may cause severe cholestasis, the drug should be stopped if idiosyncrasy or hypersensitivity develops. If there is a debate in the diagnosis, histopathological evaluation of the liver would be the major issue because of the correct diagnosis of the drug toxicity and excluding other aetiologies.

Recommendations of the Spanish Working Group on Crohn's Disease and Ulcerative Colitis (GETECCU) on the use of thiopurines in inflammatory bowel disease

Thiopurines (azathioprine and mercaptopurine) are widely used in patients with inflammatory bowel disease. In this paper, we review the main indications for their use, as well as practical aspects on efficacy, safety and method of administration. They are mainly used to maintain remission in steroid-dependent disease or with ciclosporin to control a severe ulcerative colitis flare-up, as well as to prevent postoperative Crohn's disease recurrence, and also in combination therapy with biologics. About 30-40% of patients will not respond to treatment and 10-20% will not tolerate it due to adverse effects. Before they are prescribed, immunisation status against certain infections should be checked. Determination of thiopurine methyltransferase activity (TPMT) is not mandatory but it increases initial safety. The appropriate dose is 2.5mg/kg/day for azathioprine and 1.5mg/kg/day for mercaptopurine. Some adverse effects are idiosyncratic (digestive intolerance, pancreatitis, fever, arthromyalgia, rash and some forms of hepatotoxicity). Others are dose-dependent (myelotoxicity and other types of hepatotoxicity), and their surveillance should never be interrupted during treatment. If therapy fails or adverse effects develop, management can include switching from one thiopurine to the other, reducing the dose, combining low doses of azathioprine with allopurinol and assessing metabolites, before their use is ruled out. Non-melanoma skin cancer, lymphomas and urinary tract tumours have been linked to thiopurine therapy. Thiopurine use is safe during conception, pregnancy and breastfeeding.

Drug-induced cholestasis

Cholestatic drug-induced liver injury (DILI) can be a diagnostic challenge due to a large differential diagnosis, variability in clinical presentation, and lack of serologic biomarkers associated with this condition. The clinical presentation of drug-induced cholestasis includes bland cholestasis, cholestatic hepatitis, secondary sclerosing cholangitis, and vanishing bile duct syndrome. The associate mortality of cholestatic DILI can be as high as 10%, and thus prompt recognition and removal of the offending agent is of critical importance. Several risk factors have been identified for drug-induced cholestasis, including older age, genetic determinants, and properties of certain medications. Antibiotics, particularly amoxicillin/clavulanate, remain the predominant cause of cholestatic DILI, although a variety of other medications associated with this condition have been identified. In this review, we summarize the presentation, clinical approach, risk factors, implicated medications, and management of drug-induced cholestatic liver injury. (Hepatology Communications 2017;1:726-735).

Hepatic manifestations of inflammatory bowel diseases

Inflammatory bowel diseases are associated with various hepatobiliary disorders, reported both in Crohn's disease and ulcerative colitis. They may occur at any moment in the natural course of the disease. The prevalence of liver dysfunction rises from 3% to 50% accordingly to definitions used in different studies. Fatty liver is considered as the most common hepatobiliary complication in inflammatory bowel diseases while primary sclerosing cholangitis is the most specific one. Less frequently, inflammatory bowel diseases-associated hepatobiliary disorders include: autoimmune hepatitis/ primary sclerosing cholangitis overlap syndrome, IgG4-associated cholangiopathy, primary biliary cholangitis, hepatic amyloidosis, granulomatous hepatitis, cholelithiasis, portal vein thrombosis and liver abscess. The spectrum of these manifestations varies according to the type of inflammatory bowel diseases. Treatments of inflammatory bowel diseases may cause liver toxicity, although incidence of serious complications remains low. However, early diagnosis of drug-induced liver injury is of major importance as it affects future clinical management. When facing abnormal liver tests, clinicians should undertake a full diagnostic work-up in order to determine whether the hepatic abnormalities are related to the inflammatory bowel diseases or not. Management of hepatic manifestations in inflammatory bowel diseases usually involves both hepatologists and gastroenterologists because of the complexity of some situations.

Drugs of abuse and addiction: A slippery slope toward liver injury

Substances of abuse induce alteration in neurobehavioral symptoms, which can lead to simultaneous exacerbation of liver injury. The biochemical changes of liver are significantly observed in the abused group of people using illicit drugs or drugs that are abused. A huge amount of work has been carried out by scientists for validation experiments using animal models to assess hepatotoxicity in cases of drugs of abuse. The risk of hepatotoxicity from these psychostimulants has been determined by different research groups. Hepatotoxicity of these drugs has been recently highlighted and isolated case reports always have been documented in relation to misuse of the drugs. These drugs induce liver toxicity on acute or chronic dose dependent process, which ultimately lead to liver damage, acute fatty infiltration, cholestatic jaundice, liver granulomas, hepatitis, liver cirrhosis etc. Considering the importance of drug-induced hepatotoxicity as a major cause of liver damage, this review emphasizes on various drugs of abuse and addiction which induce hepatotoxicity along with their mechanism of liver damage in clinical aspect as well as in vitro and in vivo approach. However, the mechanisms of drug-induced hepatotoxicity is dependent on reactive metabolite formation via metabolism, modification of covalent bonding between cellular components with drug and its metabolites, reactive oxygen species generation inside and outside of hepatocytes, activation of signal transduction pathways that alter cell death or survival mechanism, and cellular mitochondrial damage, which leads to alteration in ATP generation have been notified here. Moreover, how the cytokines are modulated by these drugs has been mentioned here.

Evaluation of azathioprine-induced cytotoxicity in an in vitro rat hepatocyte system

Azathioprine (AZA) is widely used in clinical practice for preventing graft rejection in organ transplantations and various autoimmune and dermatological diseases with documented unpredictable hepatotoxicity. The potential molecular cytotoxic mechanisms of AZA towards isolated rat hepatocytes were investigated in this study using “Accelerated Cytotoxicity Mechanism Screening” techniques. The concentration of AZA required to cause 50% cytotoxicity in 2 hrs at 37°C was found to be 400 μM. A significant increase in AZA-induced cytotoxicity and reactive oxygen species (ROS) formation was observed when glutathione- (GSH-) depleted hepatocytes were used. The addition of N-acetylcysteine decreased cytotoxicity and ROS formation. Xanthine oxidase inhibition by allopurinol decreased AZA-induced cytotoxicity, ROS, and hydrogen peroxide (H₂O₂) formation and increased % mitochondrial membrane potential (MMP). Addition of N-acetylcysteine and allopurinol together caused nearly complete cytoprotection against AZA-induced hepatocyte death. TEMPOL (4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl), a known ROS scavenger and a superoxide dismutase mimic, and antioxidants, like DPPD (N,N′-diphenyl-p-phenylenediamine), Trolox (a water soluble vitamin E analogue), and mesna (2-mercaptoethanesulfonate), also decreased hepatocyte death and ROS formation. Results from this study suggest that AZA-induced cytotoxicity in isolated rat hepatocytes may be partly due to ROS formation and GSH depletion that resulted in oxidative stress and mitochondrial injury.

Genes and beans: pharmacogenomics of renal transplant

Advances in the management of patients after solid organ transplantation have led to dramatic decreases in rates of acute rejection, but long-term graft and patient survival have remained unchanged. Individualized therapy after transplant will ideally provide adequate immunosuppression while limiting the adverse effects of drug therapy that significantly impact graft survival. Therapeutic drug monitoring represents the best approximation of individualized drug therapy in transplant at this time; however, obtaining pharmacogenomic data in transplant patients has the potential to enhance our current practice. Polymorphisms of target genes that impact pharmacokinetics have been identified for most immunosuppressants, including tacrolimus, cyclosporine, mycophenolate, azathioprine and sirolimus. In the future, pre-emptive assessment of a patient's genetic profile may inform drug selection and provide information on specific doses that will improve efficacy and limit toxicity.

Drug-induced cholestasis

Cholestasis caused by drugs is an important differential diagnosis in patients presenting with a biochemical cholestatic pattern. The extent of serologic tests and radiological imaging depends on the clinical context. The underlying condition of the patient and detailed information on drug use, results of rechallenge, and the documented hepatotoxicity of the drug are important to establish a diagnosis of drug-induced liver injury (DILI). Most cases of cholestatic DILI are mild, but in rare cases, ductopenia and cholestatic cirrhosis can develop. Approximately 10% of patients with cholestatic jaundice caused by drugs develop liver failure.

The long-term risk of continuous immunosuppression using thioguanides in inflammatory bowel disease

The efficacy of thiopurine treatment in the induction, and especially maintenance, of remission in inflammatory bowel disease is well proven; however, it is associated with side effects in both medium and long-term use. The potential harmful effects may be anticipated and minimised by due diligence prior to commencing these drugs followed by close monitoring of haematological and biochemical parameters once started. Careful clinical examination and history taking are also essential. Affected patients are expected to lead lives that include travel, employment and pregnancy - the implications of continued thiopurine therapy in such patients are discussed.

Azathioprine induced cholestatic hepatitis

We report a case of cholestatic hepatitis developed one week after exposure to azathioprine. The subsequent prolonged cholestatic phase was followed by full clinical remission. Current knowledge on pathogenesis and epidemiology and the diagnostic challenges presented by this rare complication are discussed, followed by recommendations for monitoring and management.

A Histopathologic Pattern of Centrilobular Hepatocyte Injury Suggests 6-Mercaptopurine-Induced Hepatotoxicity in Patients With Inflammatory Bowel Disease

Context.—Hepatotoxicity is an important side effect of thiopurine analog treatment for inflammatory bowel disease. A variety of histopathologic findings have been observed in patients with inflammatory bowel disease with thiopurine-induced hepatotoxicity, including nodular regenerative hyperplasia, vascular injury, and cholestasis.

Objective.—To describe the histologic features shared by 3 cases of thiopurine-induced hepatotoxicity in patients with inflammatory bowel disease.

Design.—We identified 3 patients with inflammatory bowel disease who developed hepatotoxicity due to 6-mercaptopurine from the educational files of the Department of Pathology at Massachusetts General Hospital (Boston). Histology slides (stained with hematoxylin-eosin, trichrome, periodic-acid Schiff with diastase digestion, and iron stains) and patients' medical records were reviewed retrospectively.

Results.—All 3 patients were receiving 6-mercaptopurine monotherapy at therapeutic doses, had normal thiopurine metabolite levels, and presented with elevated aminotransferase levels. Biopsies from all 3 cases exhibited a pattern of centrilobular hepatocyte injury characterized by ceroid-laden macrophages, hepatocyte anisonucleosis, and increased lipofuscin pigment, as well as centrilobular steatosis. Aminotransferase levels trended downward and either normalized or remained at borderline elevated levels after 6-mercaptopurine dose was reduced (in 1 patient) or discontinued (in 2 patients).

Conclusions.—Recognition of a pattern of centrilobular injury enables pathologists to suggest thiopurine-induced liver injury as the cause of elevated aminotransferases in patients with inflammatory bowel disease.

Hepatoportal sclerosis in childhood: some presenting with cholestatic features (a re-evaluation of 12 children)

Hepatoportal sclerosis (HPS) is a syndrome of obscure etiology, and is one of the causes of noncirrhotic portal hypertension (PH). We aimed to investigate this heterogeneous group of patients whose presentation showed cholestatic features, histopathologically. Between 1999 and 2009, 12 children diagnosed with HPS were retrospectively evaluated. HPS was diagnosed with evidence of PH, noncirrhotic liver biopsy with typical histopathologic findings, and exclusion of other possible causes of PH. The data was obtained from pathology reports and microscopic slides. In histopathological re-evaluation fibrosis state, aberrant portal vessels, portal tract dilation and inflammation, ductular reaction, regenerative nodular hyperplasia, acinar transformation, presence of bile pigment, and cholangitis were noted. Serum alanine aminotransferase, aspartate aminotransferase, gamma-glutamyl, alkaline phosphatase, bilirubin, and albumin levels, presentation patterns, and radiologic findings were assessed. Familial relationship degrees were also investigated. Twelve patients (9 boys, 3 girls; 3-180 months) were re-evaluated. Two pairs of the patients were siblings. Parents of 7 patients were consanguine. The most common presenting symptom was abdominal distension. Histopathologically, all patients had hepatoportal sclerosis/intimal fibrous thickening of portal vein and periportal fibrosis, acinar transformation, and regenerative nodules not surrounded by fibrous septae. Eight patients had vascular aberrations, 7 had ductular reaction, 1 showed mild cholangitis, and 1 had canalicular bile pigment. We conclude that genetic predisposition might be a possible factor for HPS development in Turkish patients and it should be kept in mind that cholestatic features noticed in histopathological evaluation may represent a variant group in the spectrum of HPS.

Liver disorders in inflammatory bowel disease

Disorders of the hepatobiliary system are relatively common extraintestinal manifestations of inflammatory bowel disease (IBD). These disorders are sometimes due to a shared pathogenesis with IBD as seen in primary sclerosing cholangitis (PSC) and small-duct primary sclerosing cholangitis (small-duct PSC). There are also hepatobiliary manifestations such as cholelithiasis and portal vein thrombosis that occur due to the effects of chronic inflammation and the severity of bowel disease. Lastly, medications used in IBD such as sulfasalazine, thiopurines, and methotrexate can adversely affect the liver. It is important to be cognizant of these disorders as some do have serious long-term consequences. The management of these disorders often requires the expertise of multidisciplinary teams to achieve the best outcomes.

Acute cholestatic liver injury caused by polyhexamethyleneguanidine hydrochloride admixed to ethyl alcohol

INTRODUCTION

Polyhexamethyleneguanidine hydrochloride (PHMG) is an antimicrobial biocide of the guanidine family. In the period from August 2006 to May 2007, more than 12500 patients were admitted to hospital with a history of drinking illegal cheap "vodka" in 44 different regions in Russia, of whom 9.4% died. In reality, the "vodka" was an antiseptic liquid composed of ethanol (≈93%), diethyl phthalate, and 0.1-0.14% PHMG (brand name "Extrasept-1").

MATERIAL AND METHODS

We performed an analysis of the clinical features and outcome in four poisoning treatment centers in the cities of Perm, Ekaterinburg, Irkutsk, and Khabarovsk. A total of 579 patients (215 females and 364 males) with similar symptoms were included.

RESULTS

The main symptoms on admission included jaundice (99.7%), skin itch (78.4%), weakness (96%), anorexia (65.8%), dizziness (65.3%), nausea (54.8%), vomiting (22.6%), stomach ache (52.7%), diarrhea (32%), and fever (50%). Mild symptoms were found in 2.5% of cases, moderate in 63%, and severe in 34.5%. Laboratory results were (mean ± SD): total bilirubin 249 ± 158 μmol/L, direct bilirubin 166 ± 97 μmol/L, cholesterol 14 ± 8 mmol/L, alanine aminotransferase 207 ± 174 IU/L, aspartate aminotransferase 174 ± 230 IU/L, alkaline phosphatase 742 ± 751 IU/L, and gamma-glutamyltranspeptidase 1199 ± 1095 IU/L. Patients generally recovered over a period of 1-5 months, although high levels of alkaline phosphatase and gamma-glutamyltranspeptidase were still found in all patients examined after 6 months. Sixty-one patients (10.5%) died between 23 and 150 days after poisoning. Local cholestasis, inflammatory infiltration, and fibrosis developing into cirrhosis were found by liver biopsy.

CONCLUSION

Acute liver injury caused by PHMG-hydrochloride or PHMG in combination with either ethanol or diethyl phthalate can be characterized as cholestatic hepatitis with a severe inflammatory component causing high mortality.

Drug monitoring in systemic lupus erythematosus: a systematic review

OBJECTIVES

To conduct an evidence-based review of the common medication toxicities and strategies and utility of drug toxicity monitoring among patients with systemic lupus erythematosus (SLE).

METHODS

PubMed and other databases were searched for articles published between the years 1960 and 2010 for keywords referring to medication toxicity or monitoring strategies for 7 drugs commonly used in SLE. All relevant English-language articles were reviewed. Most of the evidence we reviewed comprised studies that addressed the incidence of toxicity-randomized trials that compare different monitoring strategies for these drugs do not exist.

RESULTS

Data to describe the frequency of adverse events and appropriate strategies for screening for these events are scarce. Toxicities do not appear to be substantially more common among patients with SLE compared to other conditions for which these drugs are used.

CONCLUSIONS

Our review demonstrates that the scientific basis for many aspects of drug toxicity monitoring is weak and that most current recommendations are based largely on expert consensus. We present a future research agenda to address these gaps.

Azathioprine-induced severe cholestatic hepatitis in patient carrying TPMT*3C polymorphism

CASE DESCRIPTION

A 40-year-old man with pemphigus foliaceus developed a jaundice and pruritus three weeks after starting azathioprine 100 mg daily. Laboratory investigations revealed a severe cholestatic hepatitis. Azathioprine-induced hepatitis was suspected. The dosage of thiopurine methyltransferase activity showed a low activity of the enzyme and the genotype of this enzyme found a TPMT*3C heterozygous mutant allele. Azathioprine was withdrawn. The icterus regressed progressively and the hepatic tests normalised slowly. The patient had no further episodes of hepatitis over a follow-up period of 6 months.

CONCLUSION

Although, hematotoxicity seems to be associated with homozygous TPMT variants, a possible association between azathioprine hepatotoxicity and a TPMT*3C genotype should be investigated further.

Hepatopancreatobiliary manifestations and complications associated with inflammatory bowel disease

Diseases involving the hepatopancreatobiliary (HPB) system are frequently encountered in patients with inflammatory bowel disease (IBD). Hepatobiliary manifestations constitute some of the most common extraintestinal manifestations of IBD. They appear to occur with similar frequency in patients with Crohn's disease or ulcerative colitis. HPB manifestations may occur in following settings: 1) disease possibly associated with a shared pathogenetic mechanism with IBD including primary sclerosing cholangitis (PSC), small-duct PSC/pericholangitis and PSC/autoimmune hepatitis overlap, acute and chronic pancreatitis related to IBD; 2) diseases which parallel structural and physiological changes seen with IBD, including cholelithiasis, portal vein thrombosis, and hepatic abscess; and 3) diseases related to adverse effects associated with treatment of IBD, including drug-induced hepatitis, pancreatitis (purine-based agents), or liver cirrhosis (methotrexate), and reactivation of hepatitis B, and biologic agent-associated hepatosplenic lymphoma. Less common HPB manifestations that have been described in association with IBD include autoimmune pancreatitis (AIP), IgG4-associated cholangitis (IAC), primary biliary cirrhosis (PBC), fatty liver, granulomatous hepatitis, and amyloidosis. PSC is the most significant hepatobiliary manifestation associated with IBD and poses substantial challenges in management requiring a multidisciplinary approach. The natural disease course of PSC may progress to cirrhosis and ultimately require liver transplantation in spite of total proctocolectomy with ileal-pouch anal anastomosis. The association between AIP, IAC, and elevated serum IgG4 in patients with PSC is intriguing. The recently reported association between IAC and IBD may open the door to investigate these complex disorders. Further studies are warranted to help understand the pathogenesis of HPB manifestations associated with IBD, which would help clinicians better manage these patients. An interdisciplinary approach, involving gastroenterologists, hepatologists, and, in advanced cases, general, colorectal, and transplant surgeons is advocated.

Protective and damaging effects of platelets in acute cholestatic liver injury revealed by depletion and inhibition strategies

Alpha-naphthylisothiocyanate (ANIT) causes cholestatic hepatitis characterized by intrahepatic bile duct epithelial cell injury and periportal hepatocellular necrosis. The progression of ANIT-induced hepatocyte injury is reported to involve extrahepatic cells including platelets. We showed recently that the procoagulant protein tissue factor (TF) is essential for ANIT-induced coagulation and contributes to ANIT-induced liver necrosis. Platelets have been shown to express TF and can contribute to coagulation cascade activation. To this end, we tested the hypothesis that platelet-dependent coagulation contributes to ANIT-induced liver injury. In ANIT (60 mg/kg)-treated mice, activation of the coagulation cascade occurred prior to a decrease of platelets in the blood. Immunostaining for glycoprotein IIb (CD41) revealed platelet accumulation along the borders of necrotic foci in livers of ANIT-treated mice. Antibody-mediated platelet depletion did not affect coagulation but markedly affected liver histopathology in ANIT-treated mice. Platelet depletion induced marked pooling of blood within necrotic lesions consistent with parenchymal-type peliosis as early as 24 h after ANIT treatment. In contrast, treatment with the P2Y(12) inhibitor clopidogrel significantly reduced ANIT-induced hepatocyte necrosis and serum alanine aminotransferase activity but did not exaggerate bleeding into necrotic foci. Clopidogrel also reduced hepatic neutrophil accumulation but did not affect induction of Intercellular adhesion molecule-1 or chemokine CxC motif ligand-1 messenger RNA expression in liver. The data indicate that ANIT-induced coagulation is platelet independent and that platelets contribute to ANIT-induced hepatocyte necrosis by promoting neutrophil accumulation. In contrast, severe thrombocytopenia induces parenchymal-type peliosis in the livers of ANIT-treated mice, a rare hepatic lesion associated with pooling of blood in the liver.

Mercaptopurine rescue after azathioprine-induced liver injury in inflammatory bowel disease

BACKGROUND

Azathioprine (AZA) liver toxicity arises in approximately 3% of inflammatory bowel disease patients and may result in treatment discontinuation.

AIM

To describe the tolerance to mercaptopurine (MP) in patients with previous AZA-related liver injury.

METHODS

Retrospective description of 31 patients (14 Crohn's, 17 ulcerative colitis), in which AZA therapy was interrupted because of liver injury, with MP started as alternative therapy.

RESULTS

Mean AZA dose was 2.2 +/- 0.4 mg x kg/day. Median (interquartile range) of AZA exposure when liver injury was detected was 2 months (1-5.2). The type of AZA-related injury was cytolitic in 32%, cholestatic in 39% and mixed in 29%. After a median of 2.5 months (0.7-5.2), the therapy was switched to MP at a mean dose of 1.3 +/- 0.2 mg x kg/day. Median of follow-up of MP therapy was 32 months (8-54). In 87.1% of patients (95%CI: 70-96%), MP was tolerated without further liver injury; of these, 77.4% tolerated full MP doses and 9.7% tolerated lower doses. In a further cohort of 12.9% of patients, (95%CI: 3-29%), liver injury reappeared (two cholestasis, two mixed), 1-3 months after the onset of MP exposure.

CONCLUSION

The administration of MP is a good alternative in patients with AZA-related liver injury, before thiopurines are definitely discarded.

Microprocessor in controlled transdermal drug delivery of anti-cancer drugs

Microprocessor controlled transdermal delivery of anticancer drugs 5-Fluorouracil (5-FU) and 6-Mercaptopurine (6-MP) was developed and in vitro evaluation was done. Drugs were loaded based on the pharmacokinetics parameters. In vitro diffusion studies were carried at different current density (0.0, 0.1, 0.22, 0.50 mA/cm2). The patches were evaluated for the drug content, thickness, weight, folding endurance, flatness, thumb tack test and adhesive properties all were well with in the specification of transdermal patches with elegant and transparent in appearance. In vitro permeation studies through human cadaver skin showed, passive delivery (0.0 mA/cm2) of 6-MP was low. As the current density was progressively increased, the flux also increased. the flux also increased with 0.1 mA/cm2 for 15-20 min, but it was less than desired flux, 0.2 mA/cm2 for 30 min showed better flux than 0.1 mA/cm2 current, but lag time was more than 4 h, 0.5 mA/cm2 current for more than 1 h, flux was >159 microg/cm2 h which was desired flux for 6-MP. 5-FU flux reached the minimum effective concentration (MEC) of 54 microg/cm2 h with 0.5 mA/cm2 current for 30-45 min, drug concentration were within the therapeutic window in post-current phase. We concluded from Ohm's Law that as the resistance decreases, current increases. Skin resistance decrease with increase in time and current, increase in the drug permeation. Interestingly, for all investigated current densities, as soon as the current was switched off, 5-FU and 6-MP flux decreased fairly, but the controlled drug delivery can be achieved by switching the current for required period of time.

[Hepatotoxicity induced by new immunosuppressants]

Immunosuppressants are among the pharmacological agents with the greatest potential to cause adverse reactions, although induction of hepatotoxicity is paradoxical from the pathogenic point of view, since the response of the innate and acquired immune system is a key element in the chain of events leading to chemical liver damage. Hepatotoxicity induced by immunosuppressants is difficult to evaluate since these drugs are sometimes used to treat liver diseases, or in combination with other drugs that can also cause hepatotoxicity, or in the context of liver transplantation, in which rejection or biliary complications can act as confounding factors. In addition, immunosuppressant therapy can favor the development of infections, which by themselves can cause liver damage, or reactivate latent chronic viral hepatitis. Corticosteroids and calcineurin inhibitors only exceptionally cause hepatotoxicity. Methotrexate at high doses and in patients with risk factors can induce advanced fibrosis and cirrhosis. Thiopurine agents can cause a spectrum of hepatic lesions, including hepatocellular of cholestatic lesions, and hepatic vascular alterations. Leflunomide has high hepatotoxic potential, especially when combined with methotrexate. Anti-tumor necrosis factor-alpha agents have rarely been associated with hepatotoxicity, often with detectable autoantibodies, and most of the reactions - some severe - have been linked to infliximab, especially when used in patients with rheumatological diseases.

Hepatocellular carcinoma with extensive peliotic change

Peliosis hepatis is a rare lesion histologically characterized by multiple cavities representing dilated sinusoids filled with blood in the liver. Although it has been observed in the liver parenchyma in association with several diseases and medications, there are few reports of nodules of hepatocellular carcinoma (HCC) showing extensive peliotic change. We describe a case of HCC showing extensive peliotic change in the cancer nodule. A 73-year-old man with a liver tumor was referred to our hospital for further investigation. Abdominal ultrasonography revealed an 8-cm hyperechoic lesion with a halo and mosaic pattern in segment 8 (S8) of the liver. Dynamic magnetic resonance imaging of the liver showed early irregular enhancement of the peripheral part of the lesion, and the effect persisted into the late phase, spreading into the central part of the nodule. Hepatic arteriography showed the "cotton-wool" sign, usually observed in cavernous hemangiomas. Fine-needle aspiration biopsy revealed the diagnosis of HCC. Anterior sectionectomy of the liver was conducted. Histological examination of the resected specimen showed that the tumor was a well-differentiated HCC with extensive dilated sinusoid-like structures in the main portion of the nodule, suggestive of peliotic change.

Gastrointestinal complications of oncologic therapy

Gastrointestinal complications are common in patients undergoing various forms of cancer treatment, including chemotherapy, radiation therapy, and molecular-targeted therapies. Many of these complications are life-threatening and require prompt diagnosis and treatment. Complications of oncologic therapy can occur in the esophagus (esophagitis, strictures, bacterial, viral and fungal infections), upper gastrointestinal tract (mucositis, bleeding, nausea and vomiting), colon (diarrhea, graft-versus-host disease, colitis and constipation), liver (drug hepatotoxicity and graft-versus-host disease), and pancreas (pancreatitis). Treatment of the different gastrointestinal complications should be tailored to the individual patient and based on the underlying pathophysiology of the complication.

Severe Cholestatic Hepatitis Caused by Azathioprine

A male patient receiving azathioprine treatment for discoid lupus erythematodes developed severe cholestatic hepatitis between 14 and 21 days after initiation of the treatment with peak bilirubin levels of 62.4 mg/dL. Other causes of hepatic dysfunction including viral hepatitis were clinically and serologically excluded. Liver biopsy revealed cholestatic hepatocellular damage. At 14 days after discontinuation of azathioprine the liver function (transaminases and bilirubin) began to improve. Only alcaline phosphatase and gamma-glutamyl transferase remained elevated even after 4 months. This case argues for an idiosyncratic cholestatic hepatocellular damage caused by azathioprine.

Long-term outcome of using allopurinol co-therapy as a strategy for overcoming thiopurine hepatotoxicity in treating inflammatory bowel disease

BACKGROUND

Hepatotoxicity results in the withdrawal of thiopurines drugs, azathioprine (AZA) and mercaptopurine (MP), in up to 10% of patients with inflammatory bowel disease. Our group previously demonstrated that allopurinol with AZA/ciclosporin/steroid 'triple therapy' improved renal graft survival.

AIM

To confirm the hypothesis that allopurinol may alleviate thiopurine hepatotoxicity by similar mechanisms as proposed in our renal study.

METHODS

Unselected patients with acute thiopurine hepatotoxicity were offered allopurinol co-therapy with low-dose AZA or MP. The starting AZA/MP dose was determined by thiopurine methyltransferase (TPMT) activity (two patients were intermediate TPMT); then this dose was reduced to 25% for allopurinol co-therapy. Response to treatment was assessed by clinical severity indices, endoscopy and blood tests.

RESULTS

Of 11 patients (three Crohn's disease, eight ulcerative colitis) treated, nine (82%) remain in long-term remission (median 42 months) with normal liver tests. One patient also successfully bypassed flu-like symptoms. Two stopped: one nausea, one abnormal liver function (stealosis on biopsy). Leucopenia occurred in two cases and resolved with minor dose reductions.

CONCLUSIONS

Allopurinol co-therapy with low-dose AZA/MP can alleviate thiopurine hepatotoxicity. It appears safe and effective for long-term use, but requires monitoring for myelotoxicity. Assessing the TPMT activity helps tailor the AZA/MP doses.

Hepatotoxicity of 6-mercaptopurine (6-MP) and Azathioprine (AZA) in adult IBD patients

OBJECTIVE

6-Mercaptopurine (6-MP) and azathioprine (AZA) are effective in the treatment of IBD; however, drug-induced hepatotoxicity has been reported in 10-15% of pediatric patients and has been associated with the 6-MP metabolite 6-methylmercaptopurine ribonucleotide (6-MMPR) at levels >5,700 pmol/8 x 10(8) RBC. The aim of this study was to assess the prevalence of 6-MP/AZA hepatotoxicity and its correlation with serum 6-MMPR levels in adult IBD patients.

METHODS

Aminotransferases, bilirubin, and 6-MP metabolite levels were measured in 173 adult IBD patients treated with 6-MP or AZA from November 2002 to December 2003. Hepatotoxicity was defined as AST and/or ALT >2x upper limit of normal or cholestasis.

RESULTS

Eight patients (4.6%) met criteria for a diagnosis of 6-MP/AZA-induced hepatotoxicity. The mean 6-MMPR level in these 8 patients was 10,537 pmol/8 x 10(8) RBC versus 3,452 pmol/8 x 10(8) RBC in the nonhepatotoxic group (P < 0.001). Risk of hepatotoxicity above the third quartile (6-MMPR > 5,300) was 5 times that below the third quartile (11.4%vs 2.3%, P < 0.05); however, nearly 90% of all patients with 6-MMPR > 5,300 pmol/8 x 10(8) RBC had no hepatotoxicity, while almost 40% of subjects with hepatotoxicity had 6-MMPR levels below this cutoff.

CONCLUSIONS

6-MP/AZA-induced hepatotoxicity is uncommon in the adult population. Although hepatotoxicity is associated with higher mean 6-MMPR levels, the sensitivity and specificity of 6-MMPR for drug-induced hepatotoxicity was poor. Monitoring liver tests in patients on 6-MP/AZA is suggested, and dose reduction or cessation of 6-MP/AZA, even with high 6-MMPR levels, should be reserved for patients with elevated aminotransferases.

Alcohol binging causes peliosis hepatis during azathioprine therapy in Crohn's disease

Patients with inflammatory bowel disease have normal life expectancy and, due to modern immunosuppressive therapies, also a normal quality of life. Since mostly young people are affected, their social behaviour suits this environment. Alcohol binging is an increasingly disturbing factor among young people. We describe a patient with Crohn’s disease, treated with azathioprine, who developed peliosis hepatis after three epsiodes of alcohol binging. Liver toxicity was not observed previously during the course of the treatment. Azathioprine-induced peliosis hepatis is thought to be idiosyncratic in humans. From animal studies, however, it is clear that hepatic depletion of glutathione leads to azathioprine toxicity to the sinusoidal endothelial cells. Damage of these cells causes peliosis hepatis. Since alcohol binging leads to hepatic glutathione depletion, we conclude that in our patient the episodes of binging have reduced liver gluathione content and therefore this has increased azathioprine toxicity causing peliosis hepatis. The problem of alcohol binging has not yet been addressed in IBD patients undertaking immunosuppressive therapy. This should be reviewed in future considerations regarding patients advice.

Liver injury in inflammatory bowel disease: long-term follow-up study of 786 patients

BACKGROUND

The aim of the study was to evaluate the incidence of abnormality of liver tests (LTs) or hepatotoxicity in a large group of inflammatory bowel disease (IBD) patients and, specifically, to assess the incidence of azathioprine (AZA)/mercaptopurine (MP)-induced liver injury in a long-term follow-up study.

METHODS

All consecutive IBD patients followed for at least 5 years were included in this retrospective study. LTs including alanine transaminase, aspartate transaminase, alkaline phosphatase, gamma-glutamyl transferase, and bilirubin were periodically monitored. "Abnormality-of-LTs" was defined as LTs between N (upper limit of the normal range) and 2 N, and "liver injury/hepatotoxicity" as LTs>2 N.

RESULTS

A total of 786 patients were included, and 138 received AZA/MP; 120 patients (15%) and 39 (5%) presented abnormality of LTs or hepatotoxicity, respectively, during follow-up. The most frequent explanations were AZA/MP treatment and fatty liver disease. Among AZA/MP-treated patients (690 patient-years follow-up) the incidence of abnormal LTs and hepatotoxicity was, respectively, 7.1% and 2.6% per patient-year. Most patients spontaneously normalized LTs despite maintaining AZA/MP. These drugs were withdrawn due to hepatotoxicity (LTs>5 N and lack of decrease despite 50% dose reduction) in 3.6% of the patients and all of them normalized LTs.

CONCLUSIONS

In IBD patients, AZA or MP treatment induces abnormality of LTs in a relatively high proportion of the cases, but the development of true hepatotoxicity/liver injury is exceptional. Moreover, most of the cases of thiopurine-induced hepatotoxicity in IBD patients are mild, and the abnormalities in LTs spontaneously return to normal values despite AZA/MP being maintained, therapy withdrawal being necessary in only approximately 4% of the patients.

Thiopurine-induced liver injury in patients with inflammatory bowel disease: a systematic review

The mean prevalence of azathioprine (AZA) or 6-mercaptopurine (MP)-induced liver injury in patients with inflammatory bowel disease was approximately 3%, and the mean annual drug-induced liver disorder rate was only 1.4%. However, this low figure calculated from retrospective studies contrasts with a much higher incidence (>10%) reported by a prospective study. Thiopurine-induced hepatotoxicity can be grouped into three syndromes: hypersensitivity, idiosyncratic cholestatic reaction, and endothelial cell injury (with resultant raised portal pressures, veno-occlusive disease, or peliosis hepatis). A small percentage of patients present with a slight elevation of liver tests (LTs) that do not have clinical implications and LTs return to normal values during the follow-up, indicating that it is not always necessary to adjust the dose of the immunomodulator. However, when abnormalities in LTs are more marked, the dose of AZA/MP may be reduced 50%, with posterior clinical and analytical controls. With this strategy, LTs frequently normalize spontaneously, and the initial AZA/MP dose may be cautiously prescribed again. Thiopurines may induce an unusual severe cholestatic jaundice that may not regress but even progress despite thiopurine withdrawal. Therefore, these drugs should be completely withdrawn, and not only tapered, in those patients presenting clinically significant jaundice. Despite a lack of evidence that monitoring of LTs is necessary in patients receiving AZA/MP, routinely performed laboratory controls including LTs seem recommendable. However, the optimal monitoring schedule remains to be established. As long-term hepatotoxicity seems to be an unpredictable and potentially severe adverse drug reaction of 6-thioguanine, this drug should not be administered outside a clinical trial setting. (Am J Gastroenterol 2007;102:1518-527).

Azathioprine induced nodular regenerative hyperplasia in IBD patients

Purine analogues are major drugs in the treatment of inflammatory bowel diseases (IBD). We present four cases of nodular regenerative hyperplasia of the liver (NRH) developed in patients with IBD treated with azathioprine. All patients had either abnormal liver tests and/or low platelet count. Although biochemical and hematological abnormalities regressed after azathioprine withdrawal, the long term evolution of the hepatic lesions (and the risk to develop further complications including portal hypertension) remains to be determined. Male gender seems to be a major risk factor by providing a predisposing pharmacogenetic profile of purine analogue metabolism. Clinicians should be aware of this serious complication which may occur with any of the purine analogues (azathioprine, 6-mercaptopurine, and 6-thioguanine).

Review article: monitoring for drug side-effects in inflammatory bowel disease

The side-effects suitable for monitoring in patients with inflammatory bowel disease being treated with the four main groups of drugs (5-aminosalicylic acid preparations, azathioprine and 6-mercaptopurine, methotrexate, and corticosteroids) are reviewed. On the basis of the reported frequency, severity and timing of side-effects, a practical scheme of monitoring is recommended. This includes a baseline measurement of full blood count, creatinine and liver function tests in all patients. In the absence of worrying symptoms, we recommend the following: (i) no monitoring for sulfasalazine; (ii) for other 5-aminosalicylic acid preparations, the measurement of creatinine at 6 and 12 months and then annually; (iii) for azathioprine/6-mercaptopurine, thiopurine methyltransferase genotype/phenotype determination has no role in treatment monitoring, but a full blood count at 2 weeks, 1 month, 3 months and then every 3 months should be performed; (iv) for methotrexate, a full blood count and liver function tests should be performed every 3 months; (v) for steroids, dual energy X-ray absorptiometry bone scanning should be performed at the start of therapy, every year in which steroids are used if the T score is < 0, and every 3-5 years if the T score is > 0.