ω-Imidazolyl-alkyl derivatives as new preclinical drug candidates for treating non-alcoholic steatohepatitis.

Cytochrome P450 2E1 (CYP2E1)-associated reactive oxygen species production plays an important role in the development and progression of inflammatory liver diseases such as alcoholic steatohepatitis. We developed two new inhibitors for this isoenzyme, namely 12-imidazolyl-1-dodecanol (I-ol) and 1-imidazolyldodecane (I-an), and aimed to test their effects on non-alcoholic steatohepatitis (NASH). The fat-rich and CYP2E1 inducing Lieber-DeCarli diet was administered over 16 weeks of the experimental period to induce the disease in a rat model, and the experimental substances were administered simultaneously over the last four weeks. The high-fat diet (HFD) pathologically altered the balance of reactive oxygen species and raised the activities of the liver enzymes alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (AP) and γ-glutamyl-transferase (γ-GT); lowered the level of adiponectine and raised the one of tumor necrosis factor (TNF)-α; increased the hepatic triglyceride and phospholipid content and diminished the serum HDL cholesterol concentration. Together with the histological findings, we concluded that the diet led to the development of NASH. I-ol and, to a lesser extent, I-an shifted the pathological values toward the normal range, despite the continued administration of the noxious agent (HFD). The hepatoprotective drug ursodeoxycholic acid (UDCA), which is used off-label in clinical practice, showed a lower effectiveness overall. I-ol, in particular, showed extremely good tolerability during the acute toxicity study in rats. Therefore, cytochrome P450 2E1 may be considered a suitable drug target, with I-ol and I-an being promising drug candidates for the treatment of NASH.

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.

Ursodeoxycholic acid dose-dependently improves liver injury in rats fed a methionine- and choline-deficient diet.

AIM: The data on the beneficial effect of ursodeoxycholic acid (UDCA) in non-alcoholic steatohepatitis (NASH) are controversial. The difference of opinion is connected with UDCA dosage to be used. Therefore, we evaluated the dose-dependent efficacy of UDCA in experimental NASH. METHODS: Male Wistar rats were fed the methionine- and choline-deficient (MCD) diet for 10 weeks. Rats were administrated UDCA (10, 20, 40 and 80 mg/kg bodyweight intragastrically) after 6 weeks of the MCD diet. RESULTS: Animals fed the MCD diet developed severe steatohepatitis. Treatment with UDCA dose-dependently decreased liver damage, but only high-dose UDCA (80 mg/kg) significantly diminished ultrastructural changes in addition to preventing steatosis, ballooning and inflammatory changes in the liver. The activities of serum marker enzymes and the content of liver triglyceride and blood glucose were increased in MCD diet-fed rats, but decreased in all the UDCA-treated groups. Serum insulin concentration was decreased whereas the quantitative insulin sensitivity check index did not changed in MCD diet-fed groups. Serum tumor necrosis factor-α content was strongly increased after MCD diet and normalized in the UDCA-treated rats, with the most pronounced effect in the highest dose groups, 40 and 80 mg/kg. The contents of endogenous ethanol in blood and intestinal mucus were increased in MCD diet-fed rats which were significantly lowered by UDCA (40 and 80 mg/kg per day). CONCLUSION: The present data demonstrate a beneficial effect of UDCA that manifested by the decrease of liver steatosis, inflammatory signs and serum tumor necrosis factor-α content especially of the highest 40 and 80 mg/kg day doses.