Subchronic administration of mitoxantrone and the influence of enzyme inhibitors on its induced cardiotoxicity in mice: role of NRF-2/CYP2E1.

OBJECTIVE: Mitoxantrone (MTX)- induced cardiotoxicity is a clinical concern that is limiting its use. The aim of this paper, therefore, was to investigate the subchronic administration of MTX plus nonspecific/specific inhibitors of CYP450/2E1, to assess the extent of oxidative-induced injury by measuring levels of oxidative cardiac and injury biomarkers in mice and to evaluate the effects of CYP2E1 on caspase 3 activity and nuclear factor erythroid 2-related factor-2 (NRF-2). MATERIALS AND METHODS: Mice (n = 32) were divided into four treatment groups of eight: control, MTX, MTX + 4-methlypyrazole (4MP) and MTX + disulfiram (Disf). After 6 weeks of treatments, blood and heart samples were collected. RESULTS: Liquid chromatography-mass spectrometry (LCMS) analysis of MTX-treated plasma samples revealed several metabolites with different retention times. Cardiac antioxidant enzymes and creatine kinase (CK) levels were not significantly different among the groups. However, cardiac troponin and caspase 3 activity were significantly raised, with increased CYP2E1 expressions and reduced NRF-2 expression. Tissue damage was observed in all the treatment groups, including MTX, leading to the conclusion that MTX-induced cardiotoxicity was mediated by CYP2E1 activity, which initiated caspase 3 production, and decreased NRF-2 expression. CONCLUSIONS: Therefore, agents that inhibit CPY2E1 expression might attenuate MTX-induced cardiotoxicity by increasing NRF-2 expression.

Drug targeting CYP2E1 for the treatment of early-stage alcoholic steatohepatitis.

BACKGROUND AND AIMS: Alcoholic steatohepatitis (ASH)-the inflammation of fatty liver-is caused by chronic alcohol consumption and represents one of the leading chronic liver diseases in Western Countries. ASH can lead to organ dysfunction or progress to hepatocellular carcinoma (HCC). Long-term alcohol abstinence reduces this probability and is the prerequisite for liver transplantation-the only effective therapy option at present. Elevated enzymatic activity of cytochrome P450 2E1 (CYP2E1) is known to be critically responsible for the development of ASH due to excessively high levels of reactive oxygen species (ROS) during metabolization of ethanol. Up to now, no rational drug discovery process was successfully initiated to target CYP2E1 for the treatment of ASH. METHODS: In this study, we applied a rational drug design concept to develop drug candidates (NCE) including preclinical studies. RESULTS: A new class of drug candidates was generated successfully. Two of the most promising small compounds named 12-Imidazolyl-1-dodecanol (abbr.: I-ol) and 1-Imidazolyldodecane (abbr.: I-an) were selected at the end of this process of drug discovery and developability. These new ω-imidazolyl-alkyl derivatives act as strong chimeric CYP2E1 inhibitors at a nanomolar range. They restore redox balance, reduce inflammation process as well as the fat content in the liver and rescue the physiological liver architecture of rats consuming continuously a high amount of alcohol. CONCLUSIONS: Due to its oral application and therapeutic superiority over an off-label use of the hepatoprotector ursodeoxycholic acid (UDCA), this new class of inhibitors marks the first rational, pharmaceutical concept in long-term treatment of ASH.

Total sesquiterpene glycosides from Loquat (Eriobotrya japonica) leaf alleviate high-fat diet induced non-alcoholic fatty liver disease through cytochrome P450 2E1 inhibition.

Non-alcoholic fatty liver disease (NAFLD) is a chronic liver disease characterized by hepatic steatosis, which affects 20-40% of the population in the world. Loquat (Eriobotrya japonica) Leaf possesses several pharmacological actions. Many sesquiterpene glycosides were reported to be isolated exclusively from the Loquat Leaf, however, their biological activity has been rarely investigated. The present study was designed to evaluate the pharmacological effect of total sesquiterpene glycosides (TSG) in high-fat diet (HFD) induced NAFLD mice with its related mechanisms of action. Mice were fed with a normal diet or HFD for 8 weeks. TSG (25 and 100mg/kg/day), simvastatin (10mg/kg/day) or vehicle were orally administered for last 4 weeks of the 8-week HFD feeding period. From the result, it was showed that TSG significantly reduced the body weight and fat deposition in the liver of NAFLD mice. It also decreased total cholesterol (TC) and triglyceride (TG) contents in the serum. Compared with NAFLD mice, superoxide dismutase (SOD) and malondialdehyde (MDA) levels were increased and decreased after the administration of TSG in a dose of 100mg/kg, respectively. TSG reduced alanine aminotransferase (ALT) activity as well. Finally, TSG was found to suppress the expression of cytochrome P450 2E1 (CYP2E1) and the phosphorylation of c-jun terminal kinase (JNK) in NAFLD mice. In summary, this study demonstrates that TSG reduces oxidative stress by downregulating of CYP2E1 expression and JNK phosphorylation in NAFLD, and alleviates NAFLD ultimately. TSG potentially serves as bioactive compounds for the treatment of NAFLD.

Effects of rosmarinic acid on acetaminophen-induced hepatotoxicity in male Wistar rats.

CONTEXT: Drug-induced liver injury is a significant worldwide clinical problem. Rosmarinic acid (RA), a natural phenol, has antioxidant effects. OBJECTIVE: The effects of RA against acetaminophen (N-acetyl-p-amino-phenol (APAP))-induced oxidative damage and hepatotoxicity in rats were investigated. MATERIALS AND METHODS: Male Wistar rats were pretreated with RA (10, 50 and 100 mg/kg, i.g.) for one week. On day 7, rats received APAP (500 mg/kg, i.p.). Then aspartate aminotransferase (AST), alanine aminotransferase (ALT), albumin, total protein, malondialdehyde (MDA), glutathione (GSH), total antioxidant capacity (TAC), glutathione S-transferase (GST), cytochrome CYP450 and histopathological changes were determined. RESULTS: APAP-induced oxidative stress in liver by a significant increase in the level of MDA (7.6 ± 0.21 nmol/mg) as well as a decrease in the contents of TAC (1.75 ± 0.14 µmol/g), GSH (1.9 ± 0.22 µmol/g) and GST) 3.2 ± 0.28 U/mg). RA treatment decreased MDA (4.32 ± 0.35 nmol/mg) but increased the contents of TAC (3.51 ± 0.34 µmol/g), GSH (3.42 ± 0.16 µmol/g) and GST (5.71 ± 0.71 µmol/g) in APAP group. RA 100 mg/kg decreased ALT (91.5 ± 1.5 U/L), AST (169 ± 8.8 U/L) and CYP450 (3 ± 0.2 nmol/min/mg) in APAP group. Histologically RA attenuated hepatic damage by decreasing necrosis, inflammation, and haemorrhage in liver sections of APAP group. DISCUSSION AND CONCLUSIONS: This is the first report that oral administration of RA dose-dependently elicited significant hepatoprotective effects in rats through inhibition of hepatic CYP2E1 activity and lipid peroxidation. RA-protected hepatic GSH and GST reserves and total tissue antioxidant capacity.

Interleukin-32γ attenuates ethanol-induced liver injury by the inhibition of cytochrome P450 2E1 expression and inflammatory responses.

Alcohol abuse and alcoholism lead to alcoholic liver disease (ALD), which is a major type of chronic liver disease worldwide. Interleukin-32 (IL-32) is a novel cytokine involved in inflammation and cancer development. However, the role of IL-32 in chronic liver disease has not been reported. In the present paper, we tested the effect of IL-32γ on ethanol-induced liver injury in IL-32γ-overexpressing transgenic mice (IL-32γ mice) after chronic ethanol feeding. Male C57BL/6 and IL-32γ mice (10-12 weeks old) were fed on a Lieber-DeCarli diet containing 6.6% ethanol for 6 weeks. IL-32γ-transfected HepG2 and Huh7 cells, as well as primary hepatocytes from IL-32γ mice, were treated with or without ethanol. The hepatic steatosis and damage induced by ethanol administration were attenuated in IL-32γ mice. Ethanol-induced cytochrome P450 2E1 expression and hydrogen peroxide levels were decreased in the livers of IL-32γ mice, primary hepatocytes from IL-32γ mice and IL-32γ-overexpressing human hepatic cells. The ethanol-induced expression levels of cyclo-oxygenase-2 (COX-2) and IL-6 were reduced in the livers of IL-32γ mice. Because nuclear transcription factor κB (NF-κB) is a key redox transcription factor of inflammatory responses, we examined NF-κB activity. Ethanol-induced NF-κB activities were significantly lower in the livers of IL-32γ mice than in wild-type (WT) mice. Furthermore, reduced infiltration of natural killer cells, cytotoxic T-cells and macrophages in the liver after ethanol administration was observed in IL-32γ mice. These data suggest that IL-32γ prevents ethanol-induced hepatic injury via the inhibition of oxidative damage and inflammatory responses.

Glucosamine enhances paracetamol bioavailability by reducing its metabolism.

Paracetamol has an extensive first-pass metabolism that highly affects its bioavailability (BA); thus, dose may be repeated several times a day in order to have longer efficacy. However, hepatotoxicity may arise because of paracetamol metabolism. Therefore, this project aimed to increase paracetamol BA in rats by glucosamine (GlcN). At GlcN-paracetamol racemic mixture ratio of 4:1 and paracetamol dose of 10 mg/kg, paracetamol area under the curve (AUC) and maximum concentration (Cmax ) were significantly increased by 99% and 66%, respectively (p < 0.05). Furthermore, paracetamol AUC and Cmax levels were increased by 165% and 88% in rats prefed with GlcN for 2 days (p < 0.001). Moreover, GlcN significantly reduced phase Ι and phase I/ΙΙ metabolic reactions in liver homogenate by 48% and 54%, respectively. Furthermore, GlcN molecule was found to possess a good in silico binding mode into the CYP2E1 active site-forming bidentate hydrogen bonding with the Thr303 side chain. Finally, serum ALT and AST levels of rats-administered high doses of paracetamol were significantly reduced when rats were prefed with GlcN (p < 0.01). In conclusion, GlcN can increase the relative BA of paracetamol through reducing its metabolism. This phenomenon is associated with reduction in hepatocytes injury following ingestion of high doses of paracetamol.