Histopathologic analysis of suspected amiodarone hepatotoxicity

Role of vitamin-E on rat liver-amiodarone: an ultrastructural study

BACKGROUND/AIM

Amiodarone, a class III antiarrhythmic drug, has been found to be effective in the management of patients with life-threatening ventricular arrhythmias. The aim of this study was to test whether the co administration of vitamin-E with amiodarone can reduce amiodarone-induced liver damage.

MATERIALS AND METHODS

Twelve male albino rats were divided into three groups (ml vegetable oil/day by oral gavages daily for 2 weeks and were used as control group. The rats of the second group received 5.4 mg amiodarone/100 gm rat dissolved in vegetable oil daily by oral gavages for 2 weeks. In the third group, the rats received 5.4 mg amiodarone and 5 mg vitamin-E/100 gram rat dissolved in 2 ml vegetable oil by oral gavages daily for 2 weeks. Two weeks after treatment, the rats were sacrificed and liver specimens were immediately taken and processed for transmission electron microscopic examinations.

RESULTS

Sections from the rat liver receiving amiodarone examined by electron microscopy showed disrupted hepatocytes with increased vacuolations. Degenerated organelles and disrupted nuclei were observed. The microvilli of bile canaliculi were disrupted and the hepatocytes showed increased lipid contents. Both endothelial cells and Kupffer cells were damaged. Phospholipids inside the mitochondria showed a loss of cristae. Sections from the liver of rats received amiodarone and vitamin-E showed lesser effects, especially in depositions of phospholipids in the mitochondria and the whole organelles and the nucleus showed minor damage in comparison to the previous group.

CONCLUSION

Milder hepatotoxic effects are seen in rats administered amiodarone and vitamin E simultaneously suggesting that vitamin-E may play a role in amelioration of the effects of amiodarone.

Endolysosomal phospholipidosis and cytosolic lipid droplet storage and release in macrophages

This review summarizes the current knowledge of endolysosomal and cytoplasmic lipid storage in macrophages induced by oxidized LDL (Ox-LDL), enzymatically degraded LDL (E-LDL) and other atherogenic lipoprotein modifications, and their relation to the adapter protein 3 (AP-3) dependent ABCA1 and ABCG1 cellular lipid efflux pathways. We compare endolysosomal lipid storage caused either through drug induced phospholipidosis, inheritable endolysosomal and cytosolic lipid storage disorders and Ox-LDL or E-LDL induced phagosomal uptake and cytosolic lipid droplet storage in macrophages. Ox-LDL is resistant to rapid endolysosomal hydrolysis and is trapped within the endolysosomal compartment generating lamellar bodies which resemble the characteristics of phospholipidosis. Various inherited lysosomal storage diseases including sphingolipidosis, glycosphingolipidosis and cholesterylester storage diseases also present a phospholipidosis phenotype. In contrast E-LDL resembling coreless unesterified cholesterol enriched LDL-particles, with a multilamellar, liposome-like structure, lead to rapid phagosomal degradation and cytosolic lipid droplet accumulation. As a consequence the uptake of E-LDL through type I and type II phagocytosis leads to increased lipid droplet formation and moderate upregulation of ABCA1 and ABCG1 while uptake of Ox-LDL leads to a rapid expansion of the lysosomal compartment and a pronounced upregulation of the ABCA1/ABCG1/AP-3 lipid efflux pathway.

Flow cytometry, with double staining with Nile red and anti-CD3 antibody, to detect phospholipidosis in peripheral blood lymphocytes of rats treated with amiodarone

A flow cytometry method, to monitor peripheral lymphocytes phospholipidosis, has been set up using a single staining with Nile red and double staining with Nile red and anti-CD3 monoclonal antibody. Blood has been collected from rats treated with amiodarone (phospholipidogenic antiarrhythmic drug). By flow cytometer, it is possible to detect phospholipids, using Nile red, a probe for intracellular lipids staining, changing its fluorescence on the stained lipid basis. CD3 antigen has been selected to focus on T cells, to evaluate whether these cells are the target of phospholipidosis amiodarone-dependent. In the study A, Sprague-Dawley rats were treated with three different doses (75, 150, and 300 mg kg(-1) day(-1)) of amiodarone or vehicle alone, for 14 days, followed by 14 days of recovery: Data obtained show that by flow cytometry, with Nile red alone, it is possible to detect a dose- and time-related response of phospholipidosis-positive lymphocytes; a partial recovery is also assessed. In the study B, Sprague-Dawley rats were treated with a single dose (300 mg kg(-1) day(-1)) of amiodarone, for 14 days: Data obtained show that animals treated with amiodarone have a significant increase of phospholipidosis-positive lymphocytes (p = 0.008), in particular of CD3+ cells (p = 0.0056). Transmission electron microscopy analysis confirmed data obtained by flow cytometry. This work shows that flow cytometry with Nile red could be a good tool to monitor ex vivo phospholipidosis in lymphocyte cells of animals treated with amiodarone: The phospholipidogenic effect is more evident focusing on CD3+ T lymphocytes, thus suggesting that these cells are probably the target of phospholipidosis.

Interaction with the hERG channel and cytotoxicity of amiodarone and amiodarone analogues

BACKGROUND AND PURPOSE

Amiodarone (2-n-butyl-3-[3,5 diiodo-4-diethylaminoethoxybenzoyl]-benzofuran, B2-O-CH(2)CH(2)-N-diethyl) is an effective class III antiarrhythmic drug demonstrating potentially life-threatening organ toxicity. The principal aim of the study was to find amiodarone analogues that retained human ether-a-go-go-related protein (hERG) channel inhibition but with reduced cytotoxicity.

EXPERIMENTAL APPROACH

We synthesized amiodarone analogues with or without a positively ionizable nitrogen in the phenolic side chain. The cytotoxic properties of the compounds were evaluated using HepG2 (a hepatocyte cell line) and A549 cells (a pneumocyte line). Interactions of all compounds with the hERG channel were measured using pharmacological and in silico methods.

KEY RESULTS

Compared with amiodarone, which displayed only a weak cytotoxicity, the mono- and bis-desethylated metabolites, the further degraded alcohol (B2-O-CH(2)-CH(2)-OH), the corresponding acid (B2-O-CH(2)-COOH) and, finally, the newly synthesized B2-O-CH(2)-CH(2)-N-pyrrolidine were equally or more toxic. Conversely, structural analogues such as the B2-O-CH(2)-CH(2)-N-diisopropyl and the B2-O-CH(2)-CH(2)-N-piperidine were significantly less toxic than amiodarone. Cytotoxicity was associated with a drop in the mitochondrial membrane potential, suggesting mitochondrial involvement. Pharmacological and in silico investigations concerning the interactions of these compounds with the hERG channel revealed that compounds carrying a basic nitrogen in the side chain display a much higher affinity than those lacking such a group. Specifically, B2-O-CH(2)-CH(2)-N-piperidine and B2-O-CH(2)-CH(2)-N-pyrrolidine revealed a higher affinity towards hERG channels than amiodarone.

CONCLUSIONS AND IMPLICATIONS

Amiodarone analogues with better hERG channel inhibition and cytotoxicity profiles than the parent compound have been identified, demonstrating that cytotoxicity and hERG channel interaction are mechanistically distinct and separable properties of the compounds.

Amiodarone-induced hepatitis and polyneuropathy

Amiodarone chlorhydrate is a diiodated benzofuran derivative, and it is used to treat cardiac rhythm abnormalities. Hepatotoxicity is a relatively uncommon side effect of amiodarone, and symptomatic hepatic dysfunction occurs in fewer than 1% of the patients taking amiodarone. Cirrhosis is a rare complication that's been confirmed in 12 cases. Peripheral neuropathy occurs in 10% of patients taking aminodarone. We report here on an unusual case of amiodarone-induced hepatotoxicity and peripheral neurotoxicity. A 75 year old man with normal liver function was given amiodarone for treating his atrial fibrillation and heart failure. He developed nausea, vomiting, muscle weakness and wasting after 17.8 months therapy with amiodarone (400 mg orally once per day). Liver biopsy showed the presence of foam cells in the hepatic sinusoids and Mallory bodies in the periportal hepatocytes on light microscopy. Sural nerve biopsy showed demyelination, and nerve conduction studies showed mixed sensorimotor polyneuropathy. These observations show the necessity of monitoring the hepatic function and conducting neurologic examination of the patients treated with amiodarone.

Role of amiodarone on the systemic inflammatory response induced by cardiac surgery: proinflammatory actions

PURPOSE

Amiodarone (AMIO), a widely used anti-arrhythmic drug, has been shown to reduce the incidence of atrial fibrillation after cardiac surgery and also to exert immunomodulatory actions in vitro and proinflammatory effects in vivo. The present study investigated the immunomodulatory properties of AMIO in the inflammatory response induced by cardiac surgery with cardiopulmonary bypass (CPB).

METHODS

In this double-blind, placebo-controlled trial, 20 patients undergoing elective coronary artery bypass graft were randomized to receive placebo or AMIO 600 mg day(-1) orally for seven days before surgery and 45 mg hr(-1) intravenously for 48 hr postoperatively. Plasma levels of the proinflammatory markers C-reactive protein (CRP), fibrinogen (FBG), tumour necrosis factor (TNF)-alpha, interleukin (IL)-6 and monocyte chemoattractant protein (MCP)-1, and the antiinflammatory marker IL-10, were compared before and after surgery.

RESULTS

Ninety-six hours after start of surgery, plasma levels of FBG had more than doubled (2.2 +/- 0.5-fold increase, P < 0.0001). Overall, FBG formation was significantly increased in the AMIO group (P = 0.048). Monocyte chemoattractant protein 1 secretion transiently increased four hours after start of surgery (6.6 +/- 4.5-fold increase) but rapidly declined thereafter, (P < 0.0001). There was a trend toward higher MCP-1 plasma concentrations in the AMIO group (P = 0.13). The plasma levels of CRP, TNF-alpha, IL-6 and Il-10 changed significantly over time, but were not altered by AMIO treatment.

CONCLUSION

In the inflammatory response induced by cardiac surgery with CPB, our data suggest that AMIO treatment is associated with a selective trend toward proinflammatory actions.

Hepatocellular toxicity and pharmacological effect of amiodarone and amiodarone derivatives

The aim of this work was to compare hepatocellular toxicity and pharmacological activity of amiodarone (2-n-butyl-3-[3,5 diiodo-4-diethylaminoethoxybenzoyl]-benzofuran; B2-O-Et-N-diethyl) and of eight amiodarone derivatives. Three amiodarone metabolites were studied, namely, mono-N-desethylamiodarone (B2-O-Et-NH-ethyl), di-N-desethylamiodarone (B2-O-Et-NH(2)), and (2-butyl-benzofuran-3-yl)-(4-hydroxy-3,5-diiodophenyl)-methanone (B2) carrying an ethanol side chain [(2-butylbenzofuran-3-yl)-[4-(2-hydroxyethoxy)-3,5-diiodophenyl]-methanone; B2-O-Et-OH]. In addition, five amiodarone analogs were investigated, namely, N-dimethylamiodarone (B2-O-Et-N-dimethyl), N-dipropylamiodarone (B2-O-Et-N-dipropyl), B2-O-carrying an acetate side chain [[4-(2-butyl-benzofuran-3-carbonyl)-2,6-diiodophenyl]-acetic acid; B2-O-acetate], B2-O-Et carrying an propionamide side chain (B2-O-Et-propionamide), and B2-O carrying an ethyl side chain [(2-butylbenzofuran-3-yl)-(4-ethoxy-3,5-diiodophenyl)-methanone; B2-O-Et]. A concentration-dependent increase in lactate dehydrogenase leakage from HepG2 cells and isolated rat hepatocytes was observed in the presence of amiodarone and of most analogs, confirming their hepatocellular toxicity. Using freshly isolated rat liver mitochondria, amiodarone and most analogs showed a dose-dependent toxicity on the respiratory chain and on beta-oxidation, significantly reducing the respiratory control ratio and oxidation of palmitate, respectively. The reactive oxygen species concentration in hepatocytes increased time-dependently, and apoptotic/necrotic cell populations were identified using flow cytometry and annexin V/propidium iodide staining. The effect of the three least toxic amiodarone analogs on the human ether-a-go-go-related gene (hERG) channel was compared with amiodarone. Amiodarone, B2-O-acetate, and B2-O-Et-N-dipropyl (each 10 microM) significantly reduced the hERG tail current amplitude, whereas 10 microM B2-O-Et displayed no detectable effect on hERG outward potassium currents. In conclusion, three amiodarone analogs (B2-O-Et-N-dipropyl, B2-O-acetate, and B2-O-Et) showed a lower hepatocellular toxicity profile than amiodarone, and two of these analogs (B2-O-Et-N-dipropyl and B2-O-acetate) retained hERG channel interaction capacity, suggesting that amiodarone analogs with class III antiarrhythmic activity and lower hepatic toxicity could be developed.

Drug-induced phospholipidosis: issues and future directions

Numerous drugs containing a cationic amphiphilic structure are capable of inducing phospholipidosis in cells under conditions of in vivo administration or ex vivo incubation. The principal characteristics of this condition include the reversible accumulation of polar phospholipids in association with the development of unicentric or multicentric lamellated bodies within cells. There is an abundance of data providing an understanding of potential mechanisms for the induction of phospholipidosis; however, the process is likely to be complex and may differ from one drug to another. The functional consequences of the presence of this condition on cellular or tissue function are not well understood. The general consensus is that the condition is an adaptive response rather than a toxicological manifestation; however, additional studies to examine this question are needed. Until this issue is resolved, concerns about phospholipidosis will continue to exist at regulatory agencies. Procedures for the screening of potential phospholipogenic candidate compounds are available. In contrast, a clear need exists for the identification of valid biomarkers to assess the development of phospholipidosis in preclinical and clinical studies.

Effect of Amiodarone on Phospholipid Content and Composition in Heart, Lung, Kidney and Skeletal Muscle: Relationship to Alteration of Thyroid Function

To investigate the effect of chronic amiodarone treatment on tissue phospholipids, a marker of amiodarone-induced toxicity, and to test the hypothesis that tissue phospholipids changes are related to amiodarone-induced effects on thyroid function, male Wistar rats were treated with amiodarone and tissue phospholipid content and fractions were assessed. Twenty-six animals were allocated to 4 groups: (i) group 1 received amiodarone, 20 mg/kg per day, for 3 weeks (n = 6); (ii) group 2 received amiodarone for 5 weeks (n = 6); (iii) group 3 received drug for 6 weeks (n = 6), and (iv) group 4 (control group) received the diluent for 6 weeks (n = 8). Total phospholipid content of lung, kidney and skeletal muscle but not heart was increased after 3 weeks of amiodarone treatment. With longer durations of treatment, the phospholipid content was significantly (p < 0.05) reduced in all four organs. The proportion of phospholipids in different classes was modified by amiodarone treatment with the most consistent changes across different tissues being reductions in phosphatidylethanolamine and increases in phosphatidylserine. Serum thyroxine concentration was significantly (p < 0.05) reduced at 5 weeks of treatment and thereafter. There was a significant correlation between serum thyroxine and total phospholipid concentration in heart (r = 0.555; p < 0.05) and lung (r = 0.502; p < 0.05). For heart, there was a significant correlation between serum thyroxine and the distribution of phospholipid classes, mainly for phosphatidylserine even after considering amiodarone dose. The same was found in the lung. In the kidney and skeletal muscle, there was a significant (p < 0.05) correlation between serum thyroxine and the proportion of phospholipids in phosphatidylcholine and sphingomyelin. In conclusion, this study presents the novel finding of a biphasic tissue phospholipid response to amiodarone characterized by a short term increase in phospholipids in lung, kidney and skeletal muscle but not the heart followed by a long term decline in phospholipids in all four organs that is likely due to a direct action of amiodarone on phospholipid metabolism and potentially the result of amiodarone-induced reduction in thyroid function.

GENOMIC CLUSTER AND NETWORK ANALYSIS FOR PREDICTIVE SCREENING FOR HEPATOTOXICITY

The present study was undertaken to estimate the usefulness of genomic approaches to predict hepatotoxicity. Male rats were treated with acetaminophen (APAP), carbon tetrachloride (CCL), amiodarone (AD) or tetracycline (TC) at toxic doses. Their livers were extracted 6 or 24 hr after the dosings and were used for subsequent examinations. At 6 hr there were no histological changes noted in any of the groups except for the CCL group, but at 24 hr, such changes were noted in all but the AD group. Regarding genomic analysis, we performed hierarchical cluster analysis using S-plus software. The individual microarray data were clearly classified into 5 treatment-related clusters at 24 hr as well as at 6 hr, even though no morphological changes were noted at 6 hr. In the gene expression analysis using GeneSpring, transcription factor and oxidative stress- and lipid metabolism-related genes were markedly affected in all treatment groups at both time points when compared with the corresponding control values. Finally, we investigated gene networks in the above-affected genes by using Ingenuity Pathway Analysis software. Down-regulation of lipid metabolism-related genes regulated by SREBP1 was observed in all treatment groups at both time points, and up-regulation of oxidative stress-related genes regulated by Nrf2 was observed in the APAP and CCL treatment groups. From the above findings, for the application of genomic approaches to predict hepatotoxicity, we considered that cluster analysis for classification and early prediction of hepatotoxicity and network analysis for investigation of toxicological biomarkers would be useful.

Hepatic cirrhosis caused by low-dose oral amiodarone therapy

A 63-year-old man presented with ascites after therapy with amiodarone, 200 mg orally once per day for 22.5 months. A liver biopsy showed grade 3 chronic hepatitis and micronodular cirrhosis. The presence of striking microvesicular steatosis on light microscopy and lysosomal inclusion bodies on electron microscopy suggested amiodarone hepatotoxicity. This is the first reported case of amiodarone-induced hepatic cirrhosis associated with chronic treatment with 200 mg orally once per day for less than 2 years.

[Severe intrahepatic cholestasis in a 66-year old male patient with medically treated atrial fibrillation]

A 66-year-old male was admitted to hospital due to painless jaundice. Because of ischemic cardiomyopathy with paroxysmal atrial fibrillation as well as recurrent ventricular tachycardias and fibrillation he was treated with phenprocoumon and amiodarone (200 mg per day) for 2 years. Laboratory tests revealed significant elevation of the parameters of cholestasis and aminotransferase activity. Serological tests excluded infectious, autoimmune or metabolic liver diseases. Abdominal ultrasound and ERCP showed no mechanic cholestasis nor tumor of the pancreas. Cardiac congestive disease was also excluded. Severe intrahepatic cholestasis, consistent with drug-induced hepatotoxic damage, was diagnosed histologically. After discontinuing phenprocoumon the liver enzymes further increased. When amiodarone was stopped, however, laboratory parameters showed a continuous downward tendency. For prevention of malignant cardiac arrhythmia the patient received an atrioventricular defibrillator. Intrahepatic cholestasis is a rare presentation of amiodarone-induced hepatic toxicity. Liver damage can even occur after the drug has been taken for prolonged periods without any problems.

Liver cirrhosis induced by long-term administration of a daily low dose of amiodarone: A case report

The anti-arrhythmic agent amiodarone (AD) is associated with numerous adverse effects, but serious liver disease is rare. The improved safety of administration of daily low doses of AD has already been established and this regimen is used for long-term medication. Nevertheless, asymptomatic continuous liver injury by AD may increase the risk of step-wise progression of non-alcoholic fatty liver disease. We present an autopsy case of AD-induced liver cirrhosis in a patient who had been treated with a low dose of AD (200 mg/d) daily for 84 mo. The patient was a 85-year-old male with a history of ischemic heart disease. Seven years after initiation of treatment with AD, he was admitted with cardiac congestion. The total dose of AD was 528 g. Mild elevation of serum aminotransferase and hepatomegaly were present. Liver biopsy specimens revealed cirrhosis, and under electron microscopy numerous lysosomes with electron-dense, whorled, lamellar inclusions characteristic of a secondary phospholipidosis were observed. Initially, withdrawal of AD led to a slight improvement of serum aminotransferase levels, but unfortunately his general condition deteriorated and he died from complications of pneumonia and renal failure. Long-term administration of daily low doses of AD carries the risk of progression to irreversible liver injury. Therefore, periodic examination of liver function and/or liver biopsy is required for the management of patients receiving long-term treatment with AD.

Genomics, proteomics and metabonomics in toxicology: hopefully not 'fashionomics'

Genomics, proteomics and metabonomics are applied to toxicology either as stand-alone technologies or in combination, with the intention of providing a more efficient assessment of the potential side effects of new chemical entities. Two different approaches are taken: a predictive/proactive strategy based on a statistical analogy of 'signatures' of drugs to many known toxicant gene or metabolite fingerprints; and a mechanistic/reactive strategy based on the in-depth biological analysis of the gene, protein or metabolite profiles induced by one or a few compounds of interest. This article focuses on the advantages and disadvantages of these technologies, as well as the many hurdles associated with both these approaches in toxicology that have to be considered before applying them to the assessment of future drugs.

Hépatotoxicité de l'amiodarone à propos de deux observations et revue de la littérature

INTRODUCTION

Amiodarone can induced hepatic dysfunction.

OBSERVATIONS

We describe two patients who developed hepatotoxicity presenting suggestive histological features. The outcome was fatal in one case but lesions were reversible in the second case upon treatment interruption.

CONCLUSION

These observations show the necessity of hepatic monitoring of patients treated with amiodarone in order to detect potentially severe hepatotoxicity.

Chloroquine-induced phospholipidosis of the kidney mimicking Fabry's disease: case report and review of the literature

A 46-year-old female patient with Sjögren's syndrome, hypertension, and stable chronic renal insufficiency (creatinine [CR], 1.9 to 2.1 mg/dL) had a progressive worsening of renal function (CR, 5.0 mg/dL) after 11 months of chloroquine therapy (155 mg/day; cumulative dose of approximately 51 g). Light microscopy revealed nonspecific angionephrosclerosis. Electron microscopy showed accumulations of lamellated myelinoid material and occasionally also of curvilinear bodies, especially in the glomerular podocytes and to a lesser extent in vascular myothelial and endothelial cells. In the tubular system, mainly protein droplets were stored. Activity of alpha-galactosidase A was normal in isolated leukocytes (56 nmol/mg; range, 33.2 to 109 nmol/mg), ruling out Fabry's disease. Clinical, morphological, and biochemical findings were consistent with chloroquine-associated deterioration of renal function that improved considerably after discontinuation of chloroquine treatment. Adverse effects of chloroquine may aggravate preexisting renal disease. Electron microscopy is a worthwhile tool for establishing the correct diagnosis.

Mechanisms of liver steatosis in rats with systemic carnitine deficiency due to treatment with trimethylhydraziniumpropionate

Rats with systemic carnitine deficiency induced by treatment with trimethylhydraziniumpropionate (THP) develop liver steatosis. This study aims to investigate the mechanisms leading to steatosis in THP-induced carnitine deficiency. Rats were treated with THP (20 mg/100 g) for 3 or 6 weeks and were studied after starvation for 24 h. Rats treated with THP had reduced in vivo palmitate metabolism and developed mixed liver steatosis at both time points. The hepatic carnitine pool was reduced in THP-treated rats by 65% to 75% at both time points. Liver mitochondria from THP-treated rats had increased oxidative metabolism of various substrates and of beta-oxidation at 3 weeks, but reduced activities at 6 weeks of THP treatment. Ketogenesis was not affected. The hepatic content of CoA was increased by 23% at 3 weeks and by 40% at 6 weeks in THP treated rats. The cytosolic content of long-chain acyl-CoAs was increased and the mitochondrial content decreased in hepatocytes of THP treated rats, compatible with decreased activity of carnitine palmitoyltransferase I in vivo. THP-treated rats showed hepatic peroxisomal proliferation and increased plasma VLDL triglyceride and phospholipid concentrations at both time points. A reduction in the hepatic carnitine pool is the principle mechanism leading to impaired hepatic fatty acid metabolism and liver steatosis in THP-treated rats. Cytosolic accumulation of long-chain acyl-CoAs is associated with increased plasma VLDL triglyceride, phospholipid concentrations, and peroxisomal proliferation.

Pathology of steatohepatitis

Pathologists have long been involved in clinical diagnosis and investigative studies of various forms of liver disease, including alcoholic liver disease. The concept that progressive fatty liver disease may result from causes other than alcohol toxicity can be noted in the literature. However, acceptance of this as a bona fide form of liver disease has been credited to an in-depth study published in 1980 of patients gathered from cases in the files of the pathology department of the Mayo Clinic in whom liver biopsies showed histological similarities to alcoholic steatohepatitis, but for whom clinical evidence of alcohol use was absent. Subsequent studies of the natural history and pathogenesis of non-alcoholic steatohepatitis have relied on detailed histopathological correlations. This chapter will elucidate the constellation of microscopic findings, the issues of concern for pathological evaluation and the knowledge to date of their significance in various forms of fatty liver disease.

Drug hepatotoxicity

Drug-induced liver disease is a relatively common, but often unrecognized, cause of liver injury, primarily because the diagnosis is often not entertained clinically. In addition, drugs are great imitators, capable of producing nearly any clinical scenario and histopathologic lesion. Thus, when dealing with a liver biopsy from a patient with an undiagnosed liver disease, the diagnosis of drug hepatotoxicity is made by first having a high index of suspicion, and then by careful correlation of histopathologic findings with both clinical and laboratory data and with a search for appropriate precedents in the medical literature.

Drug-induced phospholipidosis: are there functional consequences?

Phospholipidosis induced by drugs with a cationic amphiphilic structure is a generalized condition in humans and animals that is characterized by an intracellular accumulation of phospholipids and the concurrent development of concentric lamellar bodies. The primary mechanism responsible for the development of phospholipidosis is an inhibition of lysosomal phospholipase activity by the drugs. While the biochemical and ultrastructural features of the condition have been well characterized, much less effort has been directed toward understanding whether the condition has adverse effects on the organism. While there are a few cationic amphiphilic drugs that have been reported to cause phospholipidosis in humans, the principal concern with this condition is in the pharmaceutical industry during preclinical testing. While this class of drugs should technically be referred to as cationic lipophilic, the term cationic amphiphilic is widely used and recognized in this field, and for this reason, the terminology cationic amphiphilic drugs (CADs) will be employed in this Minireview. The aim of this Minireview is to provide an evaluation of the state of knowledge on the functional consequences of CAD-induced phospholipidosis.

Granular cells as a marker of early amiodarone hepatotoxicity

Hepatotoxicity due to chronic amiodarone (AD) use is well described. However, hepatitis occurring after acute administration of AD has only occasionally been reported and the pathologic findings in the liver in this condition have not been well characterized. We describe an idiosyncratic reaction, in a 40-year-old man after 6 weeks of oral AD therapy, consisting of acute hepatitis, which resolved after withdrawal of the drug. The liver biopsy showed clusters of cells with granular cytoplasm. These cells were characterized as macrophages, and phospholipid membranous inclusions were demonstrated ultrastructurally in the granular cells and in the hepatocytes. Pathologists and clinicians should be aware of this subtle histologic finding when looking for evidence to support AD hepatotoxicity.

Drug-induced liver disease

The incidence of drug-induced liver disease appears to be increasing, reflecting the increasing number of new agents that have been introduced into clinical use over the past several decades. Among the topics covered, the author discusses incidence, diagnosis, risk factors, clinical presentations, hepatitis, and vascular injury. The author also reviews the hepatic injury seen with commonly prescribed drugs, emphasizing newer developments in the field and recent publications and reports.

Positive Coombs' test results in two dogs treated with amiodarone

Effects of amiodarone, an antiarrhythmic drug that is effective in suppressing severe ventricular arrhythmias that are refractory to other antiarrhythmic drugs, were evaluated in 2 dogs with cardiac disease. One dog was a Doberman Pinscher with cardiomyopathy that developed severe thrombocytopenia after receiving amiodarone for 7 months. The second was a Giant Schnauzer with acquired mitral valve degeneration that developed regenerative anemia after receiving amiodarone for 5 months. Results of direct Coombs' tests were positive in both dogs. Adverse effects of amiodarone are numerous; in dogs, the most common adverse effects are anorexia and hepatotoxicosis. Frequent CBC and serum biochemical analyses should be performed when amiodarone is administered with the intent of continuing the drug indefinitely.

Severe intrahepatic cholestasis caused by amiodarone toxicity after withdrawal of the drug: a case report and review of the literature

Cholestasis has been reported as a rare presentation among patients with severe liver injury secondary to amiodarone hepatic toxicity. We report an unusual case of amiodarone-induced cholestatic hepatotoxicity occurring after amiodarone had been discontinued and the initial abnormal liver function findings had improved. The patient, without jaundice at the initial presentation, developed severe jaundice about 4 months after withdrawal of amiodarone. Light and transmission electron microscopic examination of a specimen secured by computed tomographically guided liver biopsy was consistent with amiodarone hepatic toxicity as the cause of intrahepatic cholestasis. An abdominal ultrasound, endoscopic retrograde cholangiography, and dimethyl iminodiacetic acid and computed tomographic scans of the abdomen all failed to demonstrate any other causes for jaundice other than amiodarone toxicity. Thus, amiodarone hepatic toxicity may occur after drug withdrawal even if results of liver function tests improve. Histopathologic examination of a liver biopsy specimen is of value for diagnosis and prognosis. The liver biopsy findings, clinical course, and liver function test results are discussed, and the English-language literature on amiodarone cholestatic hepatotoxicity is reviewed.

Nonalcoholic steatohepatitis

NASH is an important form of chronic liver disease that is increasingly recognized. The diagnosis is secured by biopsy findings with similarities to alcoholic hepatitis in a patient with a confirmed history of abstinence. Obesity is a major risk factor, but the disease also occurs in the nonobese. In 20% to 40% of patients the disease can progress to various stages of fibrosis and ultimately cause cirrhosis and death from end-stage liver disease. For this reason, recognition of NASH is important, and establishing the diagnosis provides a further impetus for performing a liver biopsy as part of the evaluation of unexplained liver abnormalities. The mainstay of treatment is weight reduction in the obese. For those individuals who are not obese, continued observation is the only option currently available. Patients who develop decompensated cirrhosis should be considered for liver transplantation unless advanced age or other underlying medical illnesses are a problem. With the increasing knowledge about the pathophysiology of hepatic steatosis, it is hoped that better diagnostic tests for specific causes of NASH will be available and lead to efficacious therapy.

Adverse effects of amiodarone

Amiodarone was introduced 30 years ago as an antianginal agent and subsequently has been used as an antiarrhythmic agent. This drug was initially used for patients with malignant ventricular arrhythmias; however, currently it is being used broadly for rate and rhythm control in patients with atrial fibrillation. At first, amiodarone was primarily used by cardiologists and today it is used throughout the medical profession. Amiodarone therapy can potentially result in a wide range of adverse effects. The majority of these adverse effects are dose related and reversible. The following is a review of the adverse effects and drug interactions of amiodarone along with recommendations for identification and management of these adverse effects.

Xenobiotic-induced hepatotoxicity: mechanisms of liver injury and methods of monitoring hepatic function

Xenobiotic-induced liver injury is a clinically important etiology of hepatic disease that, if not recognized, can lead to hepatic failure. In this article we discuss the mechanisms of xenobiotic-induced liver injury, various factors that can alter the risk and severity of injury, the clinical and laboratory manifestations of injury, and the methods used to detect the presence of injury and (or) functioning liver mass.

Cytokeratin inclusions in alcoholic liver disease and their relation to the amount of alcohol intake

In the present study, the frequency and the distribution pattern of immunoreactive hepatocytic cytokeratin (CK) inclusions was investigated using the monoclonal antibody (MAb) CAM 5.2 detecting CKs 8, 18 and 19. The CK antigenicity of the inclusions was confirmed on frozen sections with MAbs for the CKs 7, 8, 17, 18 and 19. The frequency of hepatocytic CK aggregates was compared to the presence of non-alcoholic and alcoholic liver disease (ALD) as well as to the average all-year daily ethanol intake of 195 consecutive males subjected to medico-legal autopsy. Hepatocytic CK inclusions were infrequent in patients with normal liver histology, portal fibrosis and/or portal inflammation. In ALD, however, inclusions were observed in 35.6% of patients with fatty liver, in 63.2% of patients with alcoholic hepatitis, in 30.8% of patients with bridging fibrosis and in 60.0% of patients with liver cirrhosis. In all specimens studied, the inclusions were reactive only for CKs 8 and 18, CKs 7, 17, and 19 being unreactive. The frequency of inclusion bodies increased, paralleling increasing average all-year daily alcohol consumption. Compared to non-drinkers, a daily intake of between 40 and 80 g of absolute alcohol was associated with a statistically significantly (relative risk, RR = 6.6) increased risk of formation of aggregates. Similarly, daily consumption exceeding 80 g was related to increased (RR = 6.0) frequency of CK aggregates. The frequency of full-blown "classical" Mallory bodies (MBs) was, however, increased (RR = 8.9) only in patients with a daily intake exceeding 160 g.(ABSTRACT TRUNCATED AT 250 WORDS)

Receiver operating characteristic analysis of glycogenated nuclei in liver biopsy specimens: quantitative evaluation of their relationship with diabetes and obesity

Glycogenated hepatocyte nuclei are a common finding in liver biopsy specimens from patients presenting with a variety of clinical disorders. Most commonly, glycogenated nuclei from part of a spectrum of pathological changes in the diabetic or obese patient. However, no previous investigation has assessed glycogenated hepatocyte nuclei in a quantitative manner. In this study we used receiver operating characteristic (ROC) analysis to assess quantitatively the strength of glycogenated nuclei as a marker for diabetes and/or obesity. The study population consisted of 102 liver biopsy specimens from the adult population: 20 from diabetic patients, 41 from obese patients, 10 from both obese and diabetic patients, and 31 from neither diabetic nor obese patients. The mean age was 48.5 years with a range of 18 to 80 years. We evaluated the extent of glycogenated nuclei by averaging the number present per high power field over a minimum of 10 high power fields, representing all zones of the liver. The extent of steatosis was graded on a numerical scale from 1 to 10. In ROC analysis perfect tests are associated with an area of 1.0 and completely random tests with an area of 0.5. Receiver operating characteristic analysis showed that glycogenated nuclei are a relatively good test for distinguishing diabetic from nondiabetic patients (area, 0.75), a poor test for distinguishing obese from nonobese patients (area, 0.60), and a fair test for either condition (area, 0.67). In addition, we observed that glycogenated nuclei were preferentially distributed in the periportal "zone 1" of the liver, showed no correlation with steatosis, and had no relation to patient age. For our patient study population the prevalence of diabetes mellitus was 12%. At a cutoff level of four glycogenated nuclei per 400 x high power field, the specificity and sensitivity of glycogenated nuclei as a test for diabetes are 0.98 and 0.30, respectively, with a positive predictive value of 66%.

The Mallory body: morphological, clinical and experimental studies (Part 1 of a literature survey)

To aid understanding of markers of disease and predictors of outcome in alcohol-exposed systems, we undertook a literature survey of more than 700 articles to view the morphological characteristics and the clinical and experimental epidemiology of the Mallory body. Mallory bodies are filaments of intermediate diameter that contain intermediate filament components (e.g., cytokeratins) observable by conventional light microscopy or immunohistochemical methods, identical in structure regardless of initiating factors or putative pathogenesis. Although three morphological types can be identified under electron microscopy (with fibrillar structure parallel, random or absent), they remain stereotypical manifestations of hepatocyte injury. A summary of the conditions associated with Mallory bodies in the literature and their validity and potential etiological relationships is presented and discussed, including estimates on the combined light microscopic and immunohistochemical prevalences and kinetics. Emphasis is placed on proper confounder control (in particular, alcohol history), which is highly essential but often inadequate. These conditions include (mean prevalence of Mallory bodies in parentheses): Indian childhood cirrhosis (73%), alcoholic hepatitis (65%), alcoholic cirrhosis (51%), Wilson's disease (25%), primary biliary cirrhosis (24%), nonalcoholic cirrhosis (24%), hepatocellular carcinoma (23%), morbid obesity (8%) and intestinal bypass surgery (6%). Studies in alcoholic hepatitis strongly suggest a hit-and-run effect of alcohol, whereas other chronic liver diseases show evidence of gradual increase in prevalence of Mallory bodies with severity of hepatic pathology. Mallory bodies in cirrhosis do not imply alcoholic pathogenesis. Obesity, however, is associated with alcoholism and diabetes, and Mallory bodies are only present in diabetic patients if alcoholism or obesity complicates the condition. In addition, case studies on diseases in which Mallory bodies have been identified, along with pharmacological side effects and experimental induction of Mallory bodies by various antimitotic and oncogenic chemicals, are presented. Mallory bodies occur only sporadically in abetalipoproteinemia, von Gierke's disease and focal nodular hyperplasia and during hepatitis due to calcium antagonists or perhexiline maleate. Other conditions and clinical drug side effects are still putative. Finally, a variety of experimental drugs have been developed that cause Mallory body formation, but markedly different cell dynamics and metabolic pathways may raise questions about the relevance of such animal models for human Mallory body formation. In conclusion, the Mallory body is indicative but not pathognomonic of alcohol involvement. A discussion on theories of development and pathological significance transcending the clinical frameworks will be presented in a future paper.

Clinicopathologic study of alcohol-like liver disease in non-alcoholics; non-alcoholic steatohepatitis and fibrosis

Alcohol-like liver injury (ALLI) in non-alcoholics has not been elucidated in Japan. The present study attempted to characterize the clinicopathologic features of ALLI in routine liver biopsies. ALLI was found in 1% of 561 biopsy cases obtained from 1988 to May, 1991 at Kanazawa University Hospital. Laboratory data characteristically showed only a mild to moderate degree of dysfunction, and none of the cases exhibited jaundice. Hepatic histology showed a mild to moderate degree of perivenular, pericellular and/or portal stellate fibrosis with a varying degree of fatty change and inflammatory cell infiltration. Portal stellate fibrosis with a varying degree of cell infiltration was more severe than the centrilobular or pericellular fibrosis in all cases. Intralobular inflammatory cell infiltration was associated with spotty or single hepatocyte necrosis, but extensive hepatocyte necrosis was not observed. Neutrophil infiltration was absent or minimal, and lymphocytes predominated in all cases. Mallory bodies were rare and were found in a few hepatocytes of only one of the 7 cases. The above histologic findings in ALLI were very similar to those seen in liver disease in Japanese alcoholics, and were somewhat different from ALLI reported in Western countries. In cases in which hepatic fibrosis, characterized by pericellular, perivenular or portal stellate fibrosis dominated without apparent hepatic necrosis and inflammation, the term "non-alcoholic steatofibrosis" is more suitable to depict its liver histology, being very similar to the alcoholic fibrosis frequently seen in Japanese alcoholics.

Alcoholic liver disease: pathologic, pathogenetic and clinical aspects

Alcoholic liver disease includes steatosis, alcoholic hepatitis and cirrhosis. Other liver diseases of genetic origin, but with a curious association with alcohol intake, are hemochromatosis and porphyria cutanea tarda. The attribution of chronic hepatitis to alcohol intake remains speculative, and the association may reflect hepatitis C infection. Hepatic injury attributed to alcohol includes the changes reported in the fetal alcohol syndrome. Steatosis, the characteristic consequence of excess alcohol intake, is usually macrovesicular and rarely microvesicular. Acute intrahepatic cholestasis, which in rare instances accompanies steatosis, must be distinguished from other causes of intrahepatic cholestasis (e.g., drug-induced) and from mechanical obstruction of the intrahepatic bile ducts (e.g., pancreatitis, choledocholithiasis) before being accepted. Alcoholic hepatitis (steatonecrosis) is characterized by a constellation of lesions: steatosis, Mallory bodies (with or without a neutrophilic inflammatory response), megamitochondria, occlusive lesions of terminal hepatic venules, and a lattice-like pattern of pericellular fibrosis. All these lesions mainly affect zone 3 of the hepatic acinus. Other changes, observed at the ultrastructural level, are of importance in progression of the disease. They include widespread cytoplasmic shedding, and capillarization and defenestration of sinusoids. Progressive fibrosis complicating alcoholic hepatitis eventually leads to cirrhosis that is typically micronodular but can evolve to a mixed or macronodular pattern. Hepatocellular carcinoma occurs in 5 to 15% of patients with alcoholic liver disease. The clinical syndrome of alcoholic liver disease is the result of three factors--parenchymal insufficiency, portal hypertension and the clinical consequences of extrahepatic damage produced by alcohol. At the several phases of the life history of alcoholic liver disease, the individual factors play a different role. The clinical manifestations of alcoholic steatosis are mainly extrahepatic in origin. Those of alcoholic hepatitis reflect mainly parenchymal insufficiency and those of cirrhosis are mainly those of portal hypertension. Alcoholic liver injury appears to be generated by the effects of ethanol metabolism and the toxic effects of acetaldehyde, perhaps the immune responses to alcohol- or acetaldehyde-altered proteins, and questionably enhanced by viral hepatitis. Alcoholic hepatitis may be mimicked histologically, and to a varying degree clinically, by a number of conditions (obesity, diabetes, several drug-induced injuries, jejunoileal bypass, and related "shortcircuiting" of the bowel). Perhaps the most important facet of the hepatotoxicity of alcohol is its enhancement of the effects of a number of other hepatotoxic agents, among which acetaminophen is the prime example.