A review of methotrexate‐associated hepatotoxicity

Methotrexate is effective not only in treating psoriasis and rheumatoid arthritis but also various other disorders. The use of methotrexate has been somewhat limited by concerns regarding its adverse effects, including its potential for hepatotoxicity. The purpose of this article is to provide an overview of methotrexate‐associated hepatotoxicity, including risk factors, pathogenesis and recommendations for monitoring it by US, UK and European guidelines, as well as providing a brief overview of its mechanism of action and of high‐dose methotrexate.     

Monitoring and management of antituberculosis drug induced hepatotoxicity

BACKGROUND: Hepatotoxicity to antituberculosis therapy (ATT) poses a major challenge. This often results in inadequate therapy. The risk of fulminant hepatic failure and mortality is high once icteric hepatitis develops. There is no consensus on monitoring protocols and for the reintroduction of ATT. METHODS: All patients (from the Department of Internal Medicine and Gastroenterology, Jagjivanram Hospital and the Department of Gastroenterology, Bombay Hospital, Mumbai, India) with a diagnosis of tuberculosis, who were to receive ATT during the study period, were included in the present study for prospective periodic laboratory monitoring for the development of hepatotoxicity. Those patients who developed hepatotoxicity formed Group A (n = 21), whereas those who did not develop hepatotoxicity were included in Group C (n = 179). For the purpose of comparison with Group A, all the patients who presented directly with ATT induced hepatotoxicity during the study period were categorized as Group B (n = 24). Group A and B were further studied after normalization of liver functions for sequential reintroduction with therapeutic doses at a weekly interval. RESULTS: In Group A, 66.6% (14 patients) of the patients were diagnosed in the asymptomatic period. Seven patients had symptomatic hepatitis, but none had icteric illness. There were no mortalities in Group A. In contrast, all the patients in Group B had symptomatic hepatitis (75% icteric hepatitis). There was a mortality rate of 16.6% (four patients). Of the 41 patients from Groups A and B who survived, reintroduction was successful in 38/39 (97.4%). In the remaining two patients who were in Group B, reintroduction was not attempted because of decompensated liver disease. CONCLUSIONS: Periodic laboratory monitoring is important in detecting hepatotoxicity at an early stage, thereby preventing mortality. Sequential reintroduction is often successful.     

The diagnosis and management of idiosyncratic drug‐induced liver injury

Drug‐induced liver injury (DILI) is an uncommon but important cause of liver disease that can arise after exposure to a multitude of drugs and herbal and dietary supplements. The severity of idiosyncratic DILI varies from mild serum aminotransferase elevations to the development of severe liver injury that can progress to acute liver failure resulting in death or liver transplantation within days of DILI onset. Chronic liver injury that persists for more than 6 months after DILI onset is also becoming increasingly recognized in up to 20% of DILI patients. Host demographic (age, gender, race), clinical and laboratory features at DILI onset have been associated with the severity and outcome of liver injury in DILI patients. In addition to cessation of the suspect drug, other medical interventions including the use of N‐acetylcysteine and corticosteroids in selected patients have shown some clinical benefit, but additional prospective studies are needed. A number of promising diagnostic, prognostic and mechanistic serum and genetic biomarkers may help improve our understanding of the pathogenesis and treatment of idiosyncratic DILI.     

Corticosteroid therapy in drug‐induced liver injury: Pros and cons

Drug‐induced liver injury (DILI) is a liver toxicity induced by a drug or its metabolite. The incidence of DILI continues to increase and it has been an enormous challenge worldwide, while the prognosis is not optimistic. Currently, the most effective treatment for DILI is to suspend the offending drug(s) and to avoid re‐exposure, with no definitive therapy available for idiosyncratic DILI with or without acute liver failure. Given the anti‐inflammatory effects of corticosteroids, they have been widely used in DILI in clinical practice, although their efficacy remains controversial. Several studies have shown their beneficial effects but a few reports have refuted the efficacy of corticosteroids in treating patients with DILI. In this review, we summarized the history and current status of corticosteroid use in liver diseases and the pros and cons of corticosteroid treatment in DILI, and we explored the DILI candidates who may benefit from corticosteroid therapy, the administration route and dosage, and the adverse effects related to corticosteroid use.     

Pulmonary function changes in rats with taurocholate‐induced pancreatitis are attenuated by pretreatment with melatonin

Melatonin is a free radical scavenger and broad‐spectrum antioxidant with immunomodulatory effects. We studied the effects of melatonin on changes in lung function, oxidative/nitrosative stress, and inflammatory cell sequestration in an acute pancreatitis (AP)‐associated lung inflammation model. Acute pancreatitis was induced by injection of 5% sodium taurocholate into the pancreatic duct of rats. Animals were randomized into control, AP, and a melatonin pretreatment (10 mg/kg)/AP group. Functional residual capacity (FRC), lung compliance (Cchord), expiratory flow rate at 50% (FEF50), airway resistance index (RI), and peak expiratory flow rate (PEF) were evaluated. White blood cell count (WBC) and hydrogen peroxide, lung lavage fluid WBC, methylguanidine, protein, lactic dehydrogenase (LDH), nitric oxide (NO), and leukotriene B4 (LTB4) levels were determined. Lung wet‐to‐dry weight ratio, peroxynitrite, and inducible nitric oxide synthase (NOS) mRNA and protein were measured. AP induction resulted in reductions in FRC, Cchord, FEF50, and PEF, and increase in RI and lung wet‐to‐dry weight ratio. Blood and lung lavage fluid WBC, lavage fluid LDH, protein, and blood hydrogen peroxide also increased. Levels of hydroxyl radicals, nitric oxide, and LTB4 in lung lavage fluid, inducible NOS mRNA, protein expression, and peroxynitrite in lung tissue also were significantly elevated. Pretreatment with melatonin attenuated obstructive and restrictive ventilatory insufficiency induced by AP. Blood and lavage WBC, lavage LDH and protein, lung edema, oxidative/nitrosative stress, and lipoxygenase pathway derivatives were also significantly attenuated by melatonin. We conclude that melatonin decreases AP‐induced obstructive and restrictive lung function changes via its antioxidant and anti‐inflammatory properties.     

静脉应用胺碘酮致急性肝损害六例临床分析

目的分析静脉应用胺碘酮致急性肝损害的临床特点及转归。方法对我院2001年1月至2005年1月静脉应用胺碘酮后致急性肝损害6例患者应用的适应证、剂量、肝损害出现的时间及转归进行分析。结果6例患者出现急性肝损害前静脉应用胺碘酮剂量为290—3000（1322．5±973．8）mg。6例患者用药后（40±29）h肝酶开始升高，天门冬氨酸氨基转移酶（AST）峰值为199—9885（2992±3453）U／L，丙氨酸氨基转移酶（ALT）峰值为247—6750（2583±2402）U／L。停药护肝降酶治疗后（28±17）d肝酶降至正常。结论静脉应用胺碘酮可以导致急性肝损害，应及时监测肝脏功能。     

The transformation in biomarker detection and management of drug‐induced liver injury

Drug‐induced liver injury (DILI) is a major concern for patients, care givers and the pharmaceutical industry. Interpretation of the serum biomarkers routinely used to detect and monitor DILI, which have not changed in almost 50 years, can be improved with recently proposed models employing quantitative systems pharmacology. In addition, several newer serum biomarkers are showing great promise. Studies in rodents indicate that the ratio of the caspase cleaved fragment of cytokeratin 18 to total K18 in serum (termed the “apoptotic index”) estimates the relative proportions of apoptosis vs necrosis during drug‐induced liver injury. Glutamate dehydrogenase can reliably differentiate liver from muscle injury and, when serum is properly prepared, may also detect mitochondrial toxicity as a mechanism of liver injury. MicroRNA‐122 is liver‐specific, but recent data suggests it can be actively released from hepatocytes in the absence of overt toxicity limiting enthusiasm for it as a DILI biomarker. Finally, damage associated molecular patterns, particularly high mobility group box 1 and its various modified forms, are promising biomarkers of innate immune activation, which may be useful in distinguishing benign elevations in aminotransferases from those that portend clinically important liver injury. These new biomarkers are already being measured in early clinical trials, but broad acceptance will require widespread archiving of serum from diverse clinical trials and probably pre‐competitive analysis efforts. We believe that utilization of a panel of traditional and newer biomarkers in conjunction with quantitative systems pharmacology modelling approaches will transform DILI detection and risk management.     

The protective role of Hepatopoietin Cn on liver injury induced by carbon tetrachloride in rats*

Background: Hepatopoietin Cn (HPPCn) is a member of the leucine‐rich acidic nuclear protein family (LANP), and studies of partially hepatectomized (PH) mice show that levels of HPPCn mRNA increase following liver injury. Furthermore, the recombinant human protein (rhHPPCn) was shown to stimulate hepatic DNA synthesis and activate signaling pathways involved in hepatocyte proliferation in vitro and in vivo. Aim: The aim of the study was to evaluate the protective effect of rhHPPCn on liver injury and fibrosis induced by carbon tetrachloride (CCl4) injection. Methods: Wistar rats weighing 200 g were given a single and repeated intraperitoneal injections of CCl4. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activity in rat serum were measured using biochemical assay. Hepatic hydroxyproline (Hyp) level was determined in the hydrolysates of liver samples. Immunostaining and Masson's trichrome staining were conducted to evaluate hepatocyte proliferation and fibrosis. Results: The results showed that exogenous rhHPPCn could alleviate hepatocyte necrosis and protect the liver from the development of fibrotic lesions by proliferation stimulation. Additionally, HPPCn could reduce ALT/AST levels in rat serum following single and repeated CCl4 injection. Conclusion: It was suggested that HPPCn could protect hepatocytes from injury induced by CCl4 as a proliferation stimulator.     

Melatonin prevents experimental liver cirrhosis induced by thioacetamide in rats

Abstract:  Liver cirrhosis is a critical stage of chronic liver diseases that can produce liver failure, portal hypertension and hepatocarcinoma. Sustained oxidative stress plays a key role in cell damage and fibrosis induced during liver cirrhosis. We evaluated the effect of oxidative stress regulation by melatonin on the development of parenchymal destruction and stellate cell activation in experimental liver cirrhosis. Melatonin was administered to rats with liver cirrhosis induced by thioacetamide (TAA) for 1 or 3 months. Liver injury was assessed by serological analysis, as well as hematoxylin-eosin staining and the in situ apoptosis detection assay in liver sections. Oxidative stress was evaluated by lipoperoxide and reduced glutathione levels, and by the measurement of catalase and superoxide dismutase activities in liver and serum respectively. The activation of stellate cells was evaluated by α -smooth muscle actin expression in liver sections. Our results showed that TAA induced oxidative stress with extensive tissue damage and enhanced α -smooth muscle actin expression in liver. Melatonin prevented the oxidative stress-related changes associated with TAA toxicity. In conclusion, the study showed that melatonin prevents the tissue damage and fibrosis associated with TAA-induced liver cirrhosis in rats.