Effects of bezafibrate on ethanol oxidation in rats

The peroxisome proliferator-activated receptor alpha agonist fenofibrate attenuates alcohol self-administration in rats

Fibrates are a class of medications used to treat hypercholesterolemia and dyslipidemia that target nuclear peroxisome proliferator-activated receptors (PPARs). Studies have shown the PPARα agonist fenofibrate decreases voluntary EtOH consumption however its impact on the reinforcing and motivational effects of EtOH is unknown. We evaluated the ability of fenofibrate (25, 50 and 100 mg/kg), to alter EtOH (10%, w/v) and sucrose (2%, w/v) operant self-administration in rats under a FR2 schedule of reinforcement over four days and under a progressive ratio (PR) schedule on day five of treatment. Results showed fenofibrate dose-dependently decreased EtOH self-administration under both schedules of reinforcement with the greatest effects seen after four to five days of treatment. Fenofibrate decreased responding for sucrose only under the PR schedule of reinforcement and this effect was not dose-dependent. These findings provide further evidence for fenofibrate as a potential treatment for alcohol use disorder in humans.

Fenofibrate--a lipid-lowering drug--reduces voluntary alcohol drinking in rats

The administration of disulfiram raises blood acetaldehyde levels when ethanol is ingested, leading to an aversion to alcohol. This study was aimed at assessing the effect of fenofibrate on voluntary ethanol ingestion in rats. Fenofibrate reduces blood triglyceride levels by increasing fatty acid oxidation by liver peroxisomes, along with an increase in the activity of catalase, which can oxidize ethanol to acetaldehyde. UChB drinker rats were allowed to consume alcohol 10% v/v freely for 60 days, until consumption stabilized at around 7 g ethanol/kg/24 h. About 1-1.2 g ethanol/kg of this intake is consumed in the first 2 h of darkness of the circadian cycle. Fenofibrate subsequently administered (50 mg/kg/day by mouth [p.o.]) for 14 days led to a 60-70% (p < 0.001) reduction of 24-h ethanol consumption. When ethanol intake was determined within the first 2 h of darkness, the reduction was 85-90% (p < 0.001). We determined whether animals chronically allowed access to ethanol and subsequently treated with fenofibrate, would a) increase liver catalase activity, and b) increase blood acetaldehyde levels after a 24-h ethanol deprivation and the subsequent administration of 1 g ethanol/kg. The oral administration of 1 g ethanol/kg produced a rapid increase in blood (arterial) acetaldehyde in fenofibrate-treated animals versus controls also administered 1 g/kg ethanol (70 μM vs. 7 μM; p < 0.001). Liver catalase activity following fenofibrate treatment was increased 3-fold (p < 0.01). Other hepatic enzymes responsible for the metabolism of ethanol (alcohol dehydrogenase and aldehyde dehydrogenase) remained unchanged. No liver damage was induced, as measured by serum glutamic-pyruvic transaminase (GPT) activity. The effect of fenofibrate in reducing alcohol intake was fully reversible. Overall, in rats allowed chronic ethanol intake, by mouth (p.o.), fenofibrate administration increased liver catalase activity and reduced voluntary ethanol intake. The administration of 1 g ethanol/kg (p.o.) to these animals increased blood acetaldehyde levels in fenofibrate-treated animals, suggesting the possible basis for the reduction in ethanol intake.

Predicted mouse peroxisome-targeted proteins and their actual subcellular locations

BACKGROUND

The import of most intraperoxisomal proteins is mediated by peroxisome targeting signals at their C-termini (PTS1) or N-terminal regions (PTS2). Both signals have been integrated in subcellular location prediction programs. However their present performance, particularly of PTS2-targeting did not seem fitting for large-scale screening of sequences.

RESULTS

We modified an earlier reported PTS1 screening method to identify PTS2-containing mouse candidates using a combination of computational and manual annotation. For rapid confirmation of five new PTS2- and two previously identified PTS1-containing candidates we developed the new cell line CHO-perRed which stably expresses the peroxisomal marker dsRed-PTS1. Using CHO-perRed we confirmed the peroxisomal localization of PTS1-targeted candidate Zadh2. Preliminary characterization of Zadh2 expression suggested non-PPARalpha mediated activation. Notably, none of the PTS2 candidates located to peroxisomes.

CONCLUSION

In a few cases the PTS may oscillate from "silent" to "functional" depending on its surface accessibility indicating the potential for context-dependent conditional subcellular sorting. Overall, PTS2-targeting predictions are unlikely to improve without generation and integration of new experimental data from location proteomics, protein structures and quantitative Pex7 PTS2 peptide binding assays.

Phytophenols in whisky lower blood acetaldehyde level by depressing alcohol metabolism through inhibition of alcohol dehydrogenase 1 (class I) in mice

We recently reported that the maturation of whisky prolongs the exposure of the body to a given dose of alcohol by reducing the rate of alcohol metabolism and thus lowers the blood acetaldehyde level (Alcohol Clin Exp Res. 2007;31:77s-82s). In this study, administration of the nonvolatile fraction of whisky was found to lower the concentration of acetaldehyde in the blood of mice by depressing alcohol metabolism through the inhibition of liver alcohol dehydrogenase (ADH). Four of the 12 phenolic compounds detected in the nonvolatile fraction (caffeic acid, vanillin, syringaldehyde, ellagic acid), the amounts of which increase during the maturation of whisky, were found to strongly inhibit mouse ADH 1 (class I). Their inhibition constant values for ADH 1 were 0.08, 7.9, 15.6, and 22.0 mumol/L, respectively, whereas that for pyrazole, a well-known ADH inhibitor, was 5.1 mumol/L. The 2 phenolic aldehydes and ellagic acid exhibited a mixed type of inhibition, whereas caffeic acid showed the competitive type. When individually administered to mice together with ethanol, each of these phytophenols depressed the elimination of ethanol, thereby lowering the acetaldehyde concentration of blood. Thus, it was demonstrated that the enhanced inhibition of liver ADH 1 due to the increased amounts of these phytophenols in mature whisky caused the depression of alcohol metabolism and a consequent lowering of blood acetaldehyde level. These substances are commonly found in various food plants and act as antioxidants and/or anticarcinogens. Therefore, the intake of foods rich in them together with alcohol may not only diminish the metabolic toxicity of alcohol by reducing both the blood acetaldehyde level and oxidative stress, but also help limit the amount of alcohol a person drinks by depressing alcohol metabolism.

Maturation of Whisky Changes Ethanol Elimination Kinetics and Neural Effects by Increasing Nonvolatile Congeners

BACKGROUND

The maturation of distilled spirits is known to change constituent congeners to improve the qualities of smell and taste. However, it has been largely unknown how maturation modifies the pharmacokinetics or neuropharmacological effects of ethanol. We used single malt whiskies to investigate the effects of spirit maturation on ethanol metabolism and drunkenness.

METHODS

Mice were injected with 5-year (5-y) or 20-year (20-y) aged single malt whisky with a concentration of 20% (w/v) ethanol at a dose of 3 g/kg. The concentrations of ethanol and its metabolites in the blood and the duration of loss of righting reflex (LORR) were compared between the 2 whisky groups. In addition, the effects of nonvolatile congeners in whisky on the biomedical reactivities of ethanol were investigated by administering a nonvolatile fraction added to a 20% ethanol solution, whose fraction was prepared by evaporating 16-y whisky. Liver alcohol dehydrogenase (ADH) activity was measured with whisky as the substrate or in the presence of nonvolatile congeners with ethanol as the substrate.

RESULTS

The rate of ethanol elimination (mmol/kg/h) was smaller in the 20-y whisky group than in the 5-y group (p<0.01 by Fisher's protected least significant difference), which resulted in lower concentrations of blood acetaldehyde and acetate in the former group than in the latter group (p<0.01 by ANOVA). Nonvolatile congeners added to the ethanol solution also depressed the rate of ethanol elimination in mice. In vitro studies demonstrated that liver ADH activity measured with whisky as the substrate was decreased as a function of the age of the whisky, and that the activity measured with ethanol as the substrate was strongly inhibited by nonvolatile congeners. The duration of LORR was longer in the 20-y group than in the 5-y group (p<0.01). Nonvolatile congeners also prolonged the duration of ethanol-induced LORR, when administered together with ethanol.

CONCLUSION

Maturation of whisky delayed ethanol metabolism to lower the level of blood acetaldehyde and acetate with increasing inhibition of liver ADH activity by nonvolatile congeners. It also prolonged drunkenness by enhancing the neurodepressive effects of ethanol, due to increases in the amount of nonvolatile congeners. These biomedical effects of whisky maturation may reduce aversive reactions and cytotoxicity due to acetaldehyde, and may also limit overdrinking with the larger neurodepression.

Bezafibrate may attenuate biliary damage associated with chronic liver diseases accompanied by high serum biliary enzyme levels

BACKGROUND

Bezafibrate is a commonly used medicine for hyperlipidemia, and recently several reports have suggested the efficacy of bezafibrate for the treatment of primary biliary cirrhosis (PBC). To assess its efficacy for other liver diseases, we administered bezafibrate to patients with various categories of hepatobiliary impairment.

METHODS

Bezafibrate (400 mg/day) was orally administered to 67 patients with chronic liver disease [22 with PBC, six with primary sclerosing cholangitis (PSC), 20 with chronic liver disease associated with hepatitis C virus (HCV) infection (CLD-C), seven with auto immune hepatitis (AIH), ten with alcoholic liver injury, and two with drug-induced liver injury].

RESULTS

The levels of biliary enzymes, such as alkaline phosphatase and gamma-glutamyltranspeptidase, decreased promptly and dramatically. The abnormally high level of alanine aminotransferase also showed a gradual decrease over 6 months in five of the eight PBC patients, all three PSC patients, eight of the 17 CLD-C patients, and all seven alcoholic liver injury patients. The level of immunoglobulin M showed a gradual decrease in 17 of the 22 PBC patients.

CONCLUSIONS

Bezafibrate significantly reduced the level of biliary enzymes in various chronic liver diseases and may be useful for the treatment of certain liver disease subsets.

Alcohol use, vascular disease, and lipid-lowering drugs

Many epidemiological and clinical studies have shown that light-to-moderate alcohol (Alc) consumption is associated with reduced risk of coronary heart disease (CHD) and total mortality in middle-aged and elderly men and women. The plausible mechanisms for the putative cardioprotective effects include increased levels of high-density lipoprotein cholesterol, prevention of clot formation, reduced platelet aggregation, promotion of blood clot dissolution, and lowering of plasma lipoprotein (a) concentration. Individuals who need to be treated with lipid-lowering drugs, such as dyslipidemic or CHD patients, may benefit from these effects of Alc. Because hypolipidemic treatment is usually continued for life, an important issue is the suitability of Alc consumption in these patients. In the present review, the beneficial effects of Alc consumption on CHD risk, its side effects, and its safety and suitability when coadministered with hypolipidemic drugs are discussed.