A lipid lowering drug (bezafibrate) has a favorable effect on liver enzymes (Al-P and gamma-GTP)

Non-Alcoholic Fatty Liver Disease Modifies Serum Gamma-Glutamyl Transferase in Cigarette Smokers

Background

Serum gamma-glutamyl transferase (GGT) is a marker of oxidative stress, associated with increased cardiovascular (CV) risk. The impact of smoking on oxidative stress may be aggravated in individuals with non-alcoholic fatty liver disease (NAFLD). We aimed to ascertain the association of smoking on GGT levels in the presence or absence of NAFLD.

Methods

We evaluated 6,354 healthy subjects (43 ± 10 years, 79% males) without clinical cardiovascular disease (CVD) undergoing an employer-sponsored physical between December 2008 and December 2010. NAFLD was diagnosed by ultrasound and participants were categorized as current or non-smokers by self report. A multivariate linear regression of the cross-sectional association between smoking and GGT was conducted based on NAFLD status.

Results

The prevalence of NAFLD was 36% (n = 2,299) and 564 (9%) were current smokers. Smokers had significantly higher GGT levels in the presence of NAFLD (P < 0.001). After multivariable adjustment, current smoking was associated with 4.65 IU/L higher GGT level, P < 0.001, compared to non-smokers. When stratified by NAFLD, the magnitude of this association was higher in subjects with NAFLD (β-coefficient: 11.12; 95% confidence interval (CI): 5.76 - 16.48; P < 0.001); however, no such relationship was observed in those without NAFLD (β: -0.02; 95% CI: -3.59, 3.56; P = 0.992). Overall the interaction of NAFLD and smoking with GGT levels as markers of oxidative stress was statistically significant.

Conclusions

Smoking is independently associated with significantly increased oxidative stress as measured by GGT level. This association demonstrates effect modification by NAFLD status, suggesting that smoking may intensify CV risk in individuals with NAFLD.

Bezafibrate for primary biliary cirrhosis

BACKGROUND

Treatment of primary biliary cirrhosis is complicated. There are studies suggesting that bezafibrate, alone or in combination with ursodeoxycholic acid (UDCA), is effective in the treatment of primary biliary cirrhosis, but no systematic review has summarised the evidence yet.

OBJECTIVES

To assess the beneficial and harmful effects of bezafibrate in patients with primary biliary cirrhosis.

SEARCH METHODS

The Cochrane Hepato-Biliary Group Controlled Trials Register, The Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, Science Citation Index Expanded, LILACS, Clinicaltrials.gov, the WHO International Clinical Trials Registry Platform, and full text searches were conducted until November 2011. The searches in Chinese Bio-medical Literature Database, China Network Knowledge Information, Chinese Science Journal Database, Chinese Medical Citation Index, Wanfang Database, and full text searches were conducted until January 2011. Manufacturers and authors were contacted.

SELECTION CRITERIA

All randomised clinical trials comparing bezafibrate at any dose or regimen in patients with primary biliary cirrhosis with placebo or no intervention, or with another drug. Any concomitant interventions were allowed if received equally by all treatment groups in a trial.

DATA COLLECTION AND ANALYSIS

Two authors extracted data. RevMan Analysis was used for statistical analysis of dichotomous data with risk ratio (RR) or risk difference (RD), and of continuous data with mean difference (MD), both with 95% confidence intervals (CI). Methodological domains were used to assess risk of systematic errors (bias). Trial sequential analysis was used to control for random errors (play of chance).

MAIN RESULTS

Six trials with 151 Japanese patients were included. All trials had high risk of bias. Four trials compared bezafibrate plus UDCA with no intervention plus UDCA (referenced as bezafibrate versus no intervention in the remaining text), and two trials compared bezafibrate with UDCA. No patient died and no patient developed liver-related complications in any of the included trials. Bezafibrate was without significant effects on the occurrence of adverse events compared with no intervention (5/32 (16%) versus 0/28 (0%)) (RR 5.40, 95% CI 0.69 to 42.32; 3 trials with 60 patients; I² = 0%) or with UDCA (2/32 (6%) versus 0/37 (0%)) (RR 6.19, 95% CI 0.31 to 122.05; 2 trials with 69 patients; I² = 0%). Bezafibrate significantly decreased the activity of serum alkaline phosphatases compared with no intervention (MD -186.04 U/L, 95% CI -249.03 to -123.04; 4 trials with 79 patients; I² = 34%) and when compared with UDCA (MD -162.90 U/L, 95% CI -199.68 to -126.12; 2 trials with 48 patients; I² = 0%). These results were supported by trial sequential analyses. Bezafibrate compared with no intervention significantly decreased plasma immunoglobulin M (MD -164.00 mg/dl, 95% CI -259.47 to -68.53; 3 trials with 50 patients; I² = 46%) and serum bilirubin concentration (MD -0.19 mg/dl, 95% CI -0.38 to -0.00; 2 trials with 34 patients; I² = 0%). However, the latter two results were not supported by trial sequential analyses. Bezafibrate compared with no intervention had no significant effect on the activity of serum gamma-glutamyltransferase (MD -1.22 U/L, 95% CI -11.97 to 9.52; 4 trials with 79 patients; I² = 42%) and serum alanine aminotransferase (MD -5.61 U/L, 95% CI -24.50 to 13.27; 2 trials with 35 patients; I² = 34%). Bezafibrate compared with UDCA had no significant effect on the activity of serum gamma-glutamyltransferase (MD 38.44 U/L, 95% CI -180.67 to 257.55; 2 trials with 49 patients; I² = 89%), serum alanine aminotransferase (MD -2.34 U/L, 95% CI -34.73 to 30.06; 2 trials with 49 patients; I² = 95%), and plasma immunoglobulin M concentration (MD -20.23 mg/dl, 95% CI -218.71 to 178.25; 2 trials with 41 patients; I² = 90%) in random-effects model meta-analyses, but bezafibrate significantly decreased the activity of serum gamma-glutamyltransferase (MD -58.18, 95% CI -76.49 to -39.88; 2 trials with 49 patients; I² = 89%), serum alanine aminotransferase (MD -13.94, 95% CI -18.78 to -9.09; 2 trials with 49 patients; I² = 95%), and plasma immunoglobulin M concentration (MD -99.90, 95% CI -130.72 to -69.07; 2 trials with 41 patients; I² = 90%) in fixed-effect model meta-analyses. One patient had bezafibrate withdrawn due to an adverse event compared to no intervention (RD 0.03, 95% CI -0.09 to 0.16; 2 trials with 60 patients; I² = 0%).

AUTHORS' CONCLUSIONS

This systematic review did not demonstrate any effect of bezafibrate versus no intervention on mortality, liver-related morbidity, adverse events, and pruritus in patients with primary biliary cirrhosis. Furthermore, we found no significant effects of bezafibrate on mortality, liver-related morbidity, or adverse events when compared with ursodeoxycholic acid, None of the trials assessed quality of life or fatigue. The data seem to indicate a possible positive intervention effect of bezafibrate on some liver biochemistry measures compared with the control group, but the observed effects could be due to systematic errors or random errors. We need more randomised clinical trials on the effects of bezafibrate on primary biliary cirrhosis with low risks of systematic errors and random errors.

Bezafibrate treatment of primary biliary cirrhosis following incomplete response to ursodeoxycholic acid

BACKGROUND AND GOALS

Ursodeoxycholic acid (UDCA) is the only current pharmacologic treatment for primary biliary cirrhosis (PBC). However, some patients show persistent liver biochemical abnormalities even after 6 to 12 months treatment. Bezafibrate retard is a commonly used medication for hyperlipidemia. In Japanese studies, it was found to lower liver enzyme levels, apparently through its action on multiple drug resistance gene 3, a transport element of the ATP-dependent bile secretion system, and on peroxisome proliferator-activated receptor-alpha. The aim of this study was to evaluate the effect of adding bezafibrate to the treatment regimen in patients with PBC and a partial response to UDCA.

STUDY

The study group included 8 White patients, 7 women and 1 man, aged 52 to 76 years with PBC who had been treated at our Liver Institute with UDCA (900 mg/d to 1500 mg/d) for 2 to 11 years (mean, 5.7 y) with only a partial response (19% to 56% reduction in alkaline phosphatase level). Bezafibrate (400 mg/d) was added to UDCA and the patients were followed for 4 to 12 months.

RESULTS

Alkaline phosphatase levels (normal range, 35 to 104 U/L) decreased in all patients, from 140 to 360 U/L (mean, 201.2) to 68 to 158 U/L (mean, 98.4), and normalized in 6 patients. In addition, levels of gamma-glutamyl transferase (normal range, 6 to 42 U/L) decreased from 70 to 192 U/L (mean, 130) to 41 to 122 U/L (mean, 71.8). These findings were maintained throughout follow-up.

CONCLUSIONS

Combination therapy with bezafibrate and UDCA improves the biochemical profile of patients with PBC who respond only partially to UDCA. A larger controlled study is needed to evaluate the clinical implications of these findings.

Therapeutic effects of fibrates in postprandial lipemia

Hypertriglyceridemia is observed in many metabolic diseases such as the metabolic syndrome, diabetes mellitus, or mixed dyslipidemia frequently leading to premature coronary heart disease (CHD). Additionally, several studies have shown that postprandial hypertriglyceridemia is pronounced in patients with CHD, metabolic syndrome, hypertension, and other pathologic conditions. The triglyceride-rich lipoprotein remnants accumulating in the postprandial state seem to be involved in atherogenesis and in events leading to thrombosis. Since abnormal postprandial lipemia is associated with pathologic conditions, its treatment is of clinical importance.Fibrates are of significant help in managing hypertriglyceridemia. This review summarizes the effect of fibric acid derivatives on postprandial lipemia. Fibrates decrease the production of and enhance the catabolism of triglyceride-rich lipoproteins through the activation of peroxisome proliferator-activated receptor-alpha. Results of clinical studies with fibrates have confirmed their action in decreasing postprandial triglyceride levels by increasing lipoprotein lipase activity, decreasing apolipoprotein CIII production, and by increasing fatty acid oxidation in the liver.It is concluded that fibrates are effective agents in lowering the postprandial increase in remnant lipoprotein particles and retinyl palmitate. Furthermore, fibrates can also affect the postprandial lipid profile by increasing hepatic lipase levels and in some cases, by reducing cholesterol ester transfer protein activity. The main target of fibrate therapy is to improve fasting hypertriglyceridemia, which is an essential component associated with improving postprandial lipemia. Fibrates are well tolerated by patients and adverse effects have been reported rarely after their administration.

gamma-Glutamyltransferase is a promising biomarker for cardiovascular risk

Oxidative stress plays a crucial role in a variety of clinical settings of atherogenesis, and mediates many pathways linked to atherosclerosis and inflammation. gamma-Glutamyltransferase (GGT), an enzyme responsible for the extracellular catabolism of antioxidant glutathione, may directly take part in atherogenesis and evolve as a potential biochemical risk indicator of cardiovascular morbidity and mortality. Classically, GGT has been thought of as a diagnostic tool for hepatobiliary disorders and alcohol abuse. More recently, growing body of data points out that serum GGT levels can aid detection of individuals at high risk for subsequent cardiovascular events, and thus have an application in primary and secondary prevention of cardiovascular disease. Although several investigations have shown that some drugs are effective in decreasing both serum lipids and GGT, and concomitantly the incidence of subsequent cardiovascular events; large-scale randomized trials are required to explore this impact directly. Based on current experimental and epidemiological studies, we postulate here that GGT present in the serum, even within its laboratory reference intervals regarded as physiologically normal, is a promising biomarker for cardiovascular risk.

Bezafibrate stimulates canalicular localization of NBD-labeled PC in HepG2 cells by PPARalpha-mediated redistribution of ABCB4

Fibrates, including bezafibrate (BF), upregulate the expression of ATP binding cassette protein B4 (ABCB4) through gene transcription in mice. To determine the effects of BF on the expression levels of ABCB4 and on the stimulation of biliary phosphatidylcholine (PC) transport in human HepG2 hepatoblastoma cells, mRNA and protein levels as well as subcellular localization were investigated in the cells treated with BF. The canalicular accumulation of a fluorescent PC was assessed by confocal laser scanning microscopy. Treatment with 300 micromol/l BF for 24 h increased levels of ABCB4 mRNA but not protein by up to 151%. BF caused redistribution of ABCB4 into pseudocanaliculi formed between cells. In association with this redistribution, BF accelerated the accumulation of fluorescent PC in bile canaliculi (up to 163% of that in nontreated cells). Suppression of peroxisome proliferator-activated receptor alpha (PPARalpha) expression by either a small interfering RNA duplex or morpholino antisense oligonucleotide attenuated the BF-induced redistribution of ABCB4. These findings suggest that BF may enhance the capacity of human hepatocytes to direct PC into bile canaliculi via PPARalpha-mediated redistribution of ABCB4 to the canalicular membrane. This provides a rationale for the use of BF to improve cholestasis and/or cholangitis that is attributable to hypofunction of ABCB4.