Treatment of patients with non-alcoholic fatty liver disease: current views and perspectives

Promising hepatoprotective agents from the natural sources: a study of scientific evidence

Background

Natural bioactive components derived from plant secondary metabolites have been pronounced as valuable alternatives for anticipating and subsiding hepatotoxic effects and its chronic complications based on experimental verification. The focus of this review is to elucidate the commonly used modern medicine for the treatment of liver disease and how major phytoconstituents have been tested for hepatoprotective activity, mechanism of action of some promising agents from natural sources, and clinical trial data for treating in patients with different liver diseases by the aid of natural phytoconstituents.

Main text

The review shows fifteen major isolated phytoconstituents, their biological sources, chemical structures, utilized plant parts, type of extracts used, hepatoprotective assay method, and their possible mechanism of action on the hepatoprotection. Nine promising hepatoprotective leads from natural sources with their chemistry and hepatoprotective mechanism are mentioned briefly. The review further includes the recent clinical trial studies of some hepatoprotective leads and their clinical outcome with different liver disease patients. Scientific studies revealed that antioxidant properties are the central mechanism for the phytoconstituents to subside different disease pathways by upsurging antioxidant defense system of cells, scavenging free radicals, down surging lipid peroxidation, improving anti-inflammatory potential, and further protecting the hepatic cell injury. In this review, we summarize recent development of natural product-based hepatoprotective leads and their curative potential for various sort of liver diseases. Furthermore, the usefulness of hit and lead molecules from natural sources for significant clinical benefit to discover new drug molecule and downsizing the problems of medication and chemical-induced hepatotoxic effects is extrapolated.

Conclusion

Further research are encouraged to elucidate the pharmacological principle of these natural-based chemical agents which will stimulate future pharmaceutical development of therapeutically beneficial hepatoprotective regimens.

Pathophysiological Changes During Ischemia-reperfusion Injury in Rodent Hepatic Steatosis

BACKGROUND/AIM

Ischemia and reperfusion injuries may produce deleterious effects on hepatic tissue after liver surgery and transplantation. The impact of ischemia-reperfusion injury (IRI) on the liver depends on its substrate, the percentage of liver ischemic tissue subjected to IRI and the ischemia time. The consequences of IRI are more evident in pathologic liver substrates, such as steatotic livers. This review is the result of an extended bibliographic PubMed search focused on the last 20 years. It highlights basic differences encountered during IRI in lean and steatotic livers based on studies using rodent experimental models.

CONCLUSION

The main difference in cell death between lean and steatotic livers is the prevalence of apoptosis in the former and necrosis in the latter. There are also major changes in the effect of intracellular mediators, such as TNFα and IL-1β. Further experimental studies are needed in order to increase current knowledge of IRI effects and relevant mechanisms in both lean and steatotic livers, so that new preventive and therapeutic strategies maybe developed.

PINE: An Automation Tool to Extract and Visualize Protein-Centric Functional Networks

Recent surges in mass spectrometry-based proteomics studies demand a concurrent rise in speedy and optimized data processing tools and pipelines. Although several stand-alone bioinformatics tools exist that provide protein-protein interaction (PPI) data, we developed Protein Interaction Network Extractor (PINE) as a fully automated, user-friendly, graphical user interface application for visualization and exploration of global proteome and post-translational modification (PTM) based networks. PINE also supports overlaying differential expression, statistical significance thresholds, and PTM sites on functionally enriched visualization networks to gain insights into proteome-wide regulatory mechanisms and PTM-mediated networks. To illustrate the relevance of the tool, we explore the total proteome and its PTM-associated relationships in two different nonalcoholic steatohepatitis (NASH) mouse models to demonstrate different context-specific case studies. The strength of this tool relies in its ability to (1) perform accurate protein identifier mapping to resolve ambiguity, (2) retrieve interaction data from multiple publicly available PPI databases, and (3) assimilate these complex networks into functionally enriched pathways, ontology categories, and terms. Ultimately, PINE can be used as an extremely powerful tool for novel hypothesis generation to understand underlying disease mechanisms.

THE EFFECTS OF REALSIL (SILYBIN-PHOSPHOLIPID-VITAMIN E COMPLEX) ON LIVER ENZYMES IN PATIENTS WITH NON-ALCOHOLIC FATTY LIVER DISEASE (NAFLD) OR NON-ALCOHOLIC STEATO-HEPATITIS (NASH): A SYSTEMATIC REVIEW AND META-ANALYSIS OF RCTS

Background

The aim of the present study was to systematically review the effects of Realsil (silybin-phospholipid-vitamin E complex) on liver enzymes in patients with NAFLD or NASH.

Methods

We searched Web of Science, MEDLINE, Google Scholar, Cochrane Library, Science Direct, ProQuest, Scopus, and 1868 articles were found up to December 2018. Four studies that examined the effect of Realsil intake on liver enzymes among NAFLD or NASH patients were included. Exclusion criteria include: animal studies, studies with the design other than clinical trials, studies on non-adult individuals, studies that assess the effect of vitamin E, silybin, or phospholipid solely, studies that examined the effect of Realsil on other outcomes, or studies with insufficient data.

Results

The analysis demonstrated that Realsil intake led to a significant decrease in Gamma-Glutamyl Transpeptidase (GGT) levels (standardized mean difference (SMD) =-0.37; 95% confidence interval (CI]): -0.68 to -0.06). Realsil intake non-significantly decrease alanine transaminase (ALT) levels (SMD=-1.02 U/L; 95% CI: -2.23 to 0.20) and non-significantly increase aspartate aminotransferase (AST) levels (SMD = 0.17 U/L; 95% CI: -0.26-0.61).

Conclusion

Realsil intake was associated with a significantly decreased circulating GGT level without any significant effect on AST and ALT levels.

Hepatic expression of Yin Yang 1 (YY1) is associated with the non-alcoholic fatty liver disease (NAFLD) progression in patients undergoing bariatric surgery

BACKGROUND

This study is to investigate the association between the hepatic expression of Yin Yang 1 (YY1) and the progression of non-alcoholic fatty liver disease (NAFLD) in patients undergoing bariatric surgery.

METHODS

Obese patients undergoing bariatric surgery were included. Liver tissues were subjected to the quantitative real-time PCR, Western blot analysis, and immunohistochemical assay, to determine the expression levels of YY1.

RESULTS

Totally 88 patients were included. According to the NAFLD activity score (NAS), these patients were divided into the control (n = 12), steatosis (n = 20), non-defining NASH (n = 38), and NASH (n = 18) groups. Significant differences in the serum glucose, insulin, ALT, AST, and HOMA-IR levels were observed among these different NAFLD groups. Hepatic YY1 expression had correlation with serum glucose, insulin, HOMA-IR, ALT, AST, triglycerides, HDL, and GGT. Immunohistochemical analysis showed that, compared with the control group, the expression levels of YY1 were significantly higher in the non-defining NASH and NASH groups. In addition, multivariate regression model showed that the serum ALT and YY1 levels were strongly associated with the NAFLD activity.

CONCLUSIONS

Several factors are associated with NAFLD progression, including the expression of YY1. Our findings contribute to understanding of the pathogenesis of NAFLD.

TRIAL REGISTRATION

NCT03296605 , registered on September 28, 2017.

Effects of Antioxidants in Reducing Accumulation of Fat in Hepatocyte

The progress of the hepatic steatosis (HS), a clinicopathological status, is influenced by cellular oxidative stress, lipogenesis, fatty acid (FA) oxidation, and inflammatory responses. Because antioxidants are gaining attention as potent preventive agents for HS, we aimed to investigate anti-lipogenic effects of the antioxidants vitamin C (VC), N-acetylcysteine (NAC), and astaxanthin (ATX) using hepatocytes. For this, we established an in vitro model using 1 mM oleic acid (OA) and human liver hepatocellular carcinoma (HepG2) cells; 10 μM antioxidants were evaluated for their ability to reduce fat accumulation in hepatocytes. Our results showed that all three antioxidants were effective to reduce fat accumulation for the molecular targets such as reduction in lipid droplets, triglyceride (TG) concentration, reactive oxygen species (ROS) production, and cell apoptosis, as well as in gene expressions of endoplasmic reticulum (ER) stress-related effectors, lipogenesis, and inflammatory cytokines. There were simultaneous increases in diphenyl-1-picrylhydrazyl (DPPH) radical scavenging effect, cell survival, AMPK phosphorylation, NRF2-related gene expression for cellular defense, and FA β-oxidation. However, among these, ATX more effectively inhibited ER stress and lipogenesis at the intracellular level than VC or NAC. Consequently, ATX was also more effective in inhibiting cell death, lipotoxicity, and inflammation. Our result emphasizes that ATX achieved greater lipotoxicity reduction than VC and NAC.

In vitro assessment of nutraceutical compounds and novel nutraceutical formulations in a liver-steatosis-based model

Background

Steatosis is a chronic liver disease that depends on the accumulation of intracellular fatty acids. Currently, no drug treatment has been licensed for steatosis; thus, only nutritional guidelines are indicated to reduce its progression. The aim of this study is to combine different nutraceutical compounds in order to evaluate their synergistic effects on a steatosis in vitro model compared to their separate use. In particular, three different formulations based on silymarin, curcumin, vitamin E, docosahexaenoic acid (DHA), choline, and phosphatidylcholine were assayed.

Methods

Human hepatocellular carcinoma cells (HepG2 cell line) were treated with a mixture of fatty acids in order to induce an in vitro model of steatosic cells, and then the amount of intracellular fat was evaluated by Oil Red O staining. The peroxisome proliferator-activated receptors α and γ (PPARα and γ) expression, closely correlated to lipid metabolism, was evaluated. The efficiency of these receptors was evaluated through the study of LPL mRNA expression, a marker involved in the lipolysis mechanism. Superoxide dismutase (SOD-2) and malondialdehydes (MDA) in lipid peroxidation were assayed as specific biomarkers of oxidative stress. In addition, experiments were performed using human liver cells stressed to obtain a steatosis model. In particular, the content of the intracellular fat was assayed using Oil Red O staining, the activation of PPARα and γ was evaluated through western blotting analyses, and the LPL mRNA expression level was analyzed through qRT-PCR.

Results

All formulations proved effective on lipid content reduction of about 35%. The oxidative stress damage was reduced by all the substances separately and even more efficiently by the same in formulation (i.e. Formulation 1 and Formulation 3, which reduced the SOD-2 expression and induced the PPARs activation). Lipid peroxidation, was reduced about 2 fold by foormulation2 and up to 5 fold by the others compared to the cells pretreated with H₂O₂.Formulation 1, was more effective on PPARγ expression (2.5 fold increase) respect to the other compounds on FA treated hepathocytes. Beside, LPL was activated also by Formulation 3 and resulted in a 5 to 9 fold-increase respect to FA treated control.

Conclusions

Our results proved that the formulations tested could be considered suitable support to face steatosis disease beside the mandatory dietetic regimen.

Qualitative and Quantitative Evaluation of Dietary Intake in Patients with Non-Alcoholic Steatohepatitis

There are very few reports about the intake of nutrients for the development or progression of non-alcoholic steatohepatitis (NASH). The aim of this study was to identify the dietary habits and the nutrient intake in patients with NASH, in comparison to chronic hepatitis C (HCV)-related patients. We prospectively evaluated the intake of macronutrients and micronutrients in 124 NAFLD and 162 HCV patients, compared to 2326 subjects as a control group. We noticed major differences in macro- and micronutrients intakes in NASH and HCV patients compared to controls. Proteins, carbohydrate (glucose, fructose, sucrose, maltose and amide), saturated fatty acid (SFA), monounsaturated fatty acid (MUFA), folic acid, vitamin A and C (p < 0.0001), and thiamine (p < 0.0003) ingestion was found to be higher in patients with NASH, while total lipids, polyunsaturated fatty acid (PUFA), riboflavin and vitamin B6 daily intake were lower compared to controls (p < 0.0001). Similarly, NASH patients had significantly reduced carbohydrate intake (p < 0.0001) and an increased intake of calcium (p < 0.0001) compared to HCV positive patients. Finally, we showed in NASH males an increase in the intake of SFA, PUFA, soluble carbohydrates (p < 0.0001) and a decrease in the amount of fiber (p < 0.0001) compared to control males. In NASH female population, we showed an increase of daily total calories, SFA, MUFA, soluble carbohydrates, starch and vitamin D ingested (p < 0.0001) with a reduction of fibers and calcium (p < 0.0001) compared to control females. This study showed how NASH patients’ diets, in both male and females, is affected by a profound alteration in macro- and micronutrients intake.

The effect of berberis vulgaris extract on transaminase activities in non-alcoholic Fatty liver disease

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent liver disorder in western countries and an important cause of liver cirrhosis, as well as liver failure. Up to now, 20‒40% of the individuals suffer from this disorder and its prevalence is estimated around 5‒30% in Asia. The NAFLD is one of the most prevalent causes for increases in liver enzymes and has a close relationship with obesity, dyslipidemia, hypertension, and type II diabetes. However, no definite treatment has been identified for it yet.

OBJECTIVES

The present study aimed to investigate the effect of berberis vulgaris extract in inducing changes in liver enzymes levels.

PATIENTS AND METHODS

The present clinical trial was conducted on 80 patients, including 32 males (40%) and 48 females (60%), who were randomly assigned into two groups of case and control. All the patients had ultrasound evidence of lipid accumulation in the liver and increases in liver enzymes. The case group received two capsules (750 mg) containing berberis vulgaris extract every day for 3 months, while the control group was treated with placebo. The weight, liver transaminases levels and lipid profiles of the two groups were assessed before, during, and after the study.

RESULTS

In the case group, the mean serum levels of alanine transaminase (ALT) and aspartate transaminase (AST) decreased from 49 to 27.48 and 48.22 to 29.8 u/L, respectively, which was statistically significant compared to the control group (P < 0.001, P < 0.001). In the control group, the mean of ALT and AST decreased from 50.4 to 46.8 and 45.7 to 44.9 u/L, respectively. The difference was not statistically significant. In addition, a significant decrease was observed in weight, triglycerides, and cholesterol, while no significant change was found in fasting blood sugar, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL).

CONCLUSIONS

Considering the significant decrease in the liver enzymes, triglycerides and cholesterol after using berberis vulgaris extract, further studies with larger sample sizes will identify the accurate dose as well as duration of consumption for this extract, to recommend in the treatment of patients with NAFLD.

Oxidative stress, cardiolipin and mitochondrial dysfunction in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is today considered the most common form of chronic liver disease, affecting a high proportion of the population worldwide. NAFLD encompasses a large spectrum of liver damage, ranging from simple steatosis to steatohepatitis, advanced fibrosis and cirrhosis. Obesity, hyperglycemia, type 2 diabetes and hypertriglyceridemia are the most important risk factors. The pathogenesis of NAFLD and its progression to fibrosis and chronic liver disease is still unknown. Accumulating evidence indicates that mitochondrial dysfunction plays a key role in the physiopathology of NAFLD, although the mechanisms underlying this dysfunction are still unclear. Oxidative stress is considered an important factor in producing lethal hepatocyte injury associated with NAFLD. Mitochondrial respiratory chain is the main subcellular source of reactive oxygen species (ROS), which may damage mitochondrial proteins, lipids and mitochondrial DNA. Cardiolipin, a phospholipid located at the level of the inner mitochondrial membrane, plays an important role in several reactions and processes involved in mitochondrial bioenergetics as well as in mitochondrial dependent steps of apoptosis. This phospholipid is particularly susceptible to ROS attack. Cardiolipin peroxidation has been associated with mitochondrial dysfunction in multiple tissues in several physiopathological conditions, including NAFLD. In this review, we focus on the potential roles played by oxidative stress and cardiolipin alterations in mitochondrial dysfunction associated with NAFLD.

Molecular pathways in non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is a clinicopathological change characterized by the accumulation of triglycerides in hepatocytes and has frequently been associated with obesity, type 2 diabetes mellitus, hyperlipidemia, and insulin resistance. It is an increasingly recognized condition that has become the most common liver disorder in developed countries, affecting over one-third of the population and is associated with increased cardiovascular- and liver-related mortality. NAFLD is a spectrum of disorders, beginning as simple steatosis. In about 15% of all NAFLD cases, simple steatosis can evolve into non-alcoholic steatohepatitis, a medley of inflammation, hepatocellular injury, and fibrosis, often resulting in cirrhosis and even hepatocellular cancer. However, the molecular mechanism underlying NAFLD progression is not completely understood. Its pathogenesis has often been interpreted by the “double-hit” hypothesis. The primary insult or the “first hit” includes lipid accumulation in the liver, followed by a “second hit” in which proinflammatory mediators induce inflammation, hepatocellular injury, and fibrosis. Nowadays, a more complex model suggests that fatty acids (FAs) and their metabolites may be the true lipotoxic agents that contribute to NAFLD progression; a multiple parallel hits hypothesis has also been suggested. In NAFLD patients, insulin resistance leads to hepatic steatosis via multiple mechanisms. Despite the excess hepatic accumulation of FAs in NAFLD, it has been described that not only de novo FA synthesis is increased, but FAs are also taken up from the serum. Furthermore, a decrease in mitochondrial FA oxidation and secretion of very-low-density lipoproteins has been reported. This review discusses the molecular mechanisms that underlie the pathophysiological changes of hepatic lipid metabolism that contribute to NAFLD.

Serum oxidative stress markers and lipidomic profile to detect NASH patients responsive to an antioxidant treatment: a pilot study

Liver steatosis can evolve to steatohepatitis (NASH) through a series of biochemical steps related to oxidative stress in hepatocytes. Antioxidants, such as silybin, have been proposed as a treatment of patients with nonalcoholic fatty liver disease (NAFLD) and NASH. In this study, we evaluated, in patients with histologically documented NASH, the oxidant/antioxidant status and lipid "fingerprint" in the serum of NASH patients, both in basal conditions and after 12 months of treatment with silybin-based food integrator Realsil (RA). The oxidant/antioxidant status analysis showed the presence of a group of patients with higher basal severity of disease (NAS scores 4.67 ± 2.5) and a second group corresponding to borderline NASH (NAS scores = 3.8 ± 1.5). The chronic treatment with RA changed the NAS score in both groups that reached the statistical significance only in group 2, in which there was also a significant decrease of serum lipid peroxidation. The lipidomic profile showed a lipid composition similar to that of healthy subjects with a restoration of the values of free cholesterol, lysoPC, SM, and PC only in group 2 of patients after treatment with RA. Conclusion. These data suggest that lipidomic and/or oxidative status of serum from patients with NASH could be useful as prognostic markers of response to an antioxidant treatment.

The relationship of serum uric acid with non-alcoholic fatty liver disease

OBJECTIVES

Non-alcoholic fatty liver disease (NAFLD) is a clinicopathological entity which is characterized by the presence of fat droplets in hepatocytes without alcohol consumption, representing a spectrum of hepatic injuries, ranging from simple steatosis (SS) to non-alcoholic steatohepatitis (NASH), fibrosis, and cirrhosis. In recent years, experimental and observational studies suggest a role for serum uric acid (SUA) in NAFLD. However, there are few reports investigating SUA in histologically proven NAFLD. The aim of the present study was to evaluate the relationship of SUA with liver histology in non-diabetic patients with NAFLD.

DESIGN AND METHODS

A total of 242 male patients with NAFLD (102 with NASH and 140 with SS) were included. Histopathological evaluation was carried out according to Kleiner's scoring scale. Hyperuricemia was diagnosed as SUA of more than 7 mg/dL.

RESULTS

The prevalence of hyperuricemia was 33.4%. SUA levels in patients with NASH were significantly higher than those of SS (p=0.035). Univariate and multivariate analyses both demonstrated that hyperuricemia had a significant association with younger age [OR (95%CI), 0.930 (0.884-0.979), p=0.005], higher body mass index [OR (95%CI), 1.173 (1.059-1.301), p=0.002] and hepatocellular ballooning [OR (95%CI), 1.678 (1.041-2.702), p=0.033].

CONCLUSIONS

Hyperuricemia is a common finding in patients with NAFLD and is independently associated with early histological findings in this clinically relevant condition. Further longitudinal studies are needed to characterize the role of SUA in the natural history of NAFLD.

Clinical approaches to non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) ranges from simple steatosis to nonalcoholic steatohepatitis (NASH), leading to fibrosis and potentially cirrhosis, and it is one of the most common causes of liver disease worldwide. NAFLD is associated with other medical conditions such as metabolic syndrome, obesity, cardiovascular disease and diabetes. NASH can only be diagnosed through liver biopsy, but noninvasive techniques have been developed to identify patients who are most likely to have NASH or fibrosis, reducing the need for liver biopsy and risk to patients. Disease progression varies between individuals and is linked to a number of risk factors. Mechanisms involved in the pathogenesis are associated with diet and lifestyle, influx of free fatty acids to the liver from adipose tissue due to insulin resistance, hepatic oxidative stress, cytokines production, reduced very low-density lipoprotein secretion and intestinal microbiome. Weight loss through improved diet and increased physical activity has been the cornerstone therapy of NAFLD. Recent therapies such as pioglitazone and vitamin E have been shown to be beneficial. Omega 3 polyunsaturated fatty acids and statins may offer additional benefits. Bariatric surgery should be considered in morbidly obese patients. More research is needed to assess the impact of these treatments on a long-term basis. The objective of this article is to briefly review the diagnosis, management and treatment of this disease in order to aid clinicians in managing these patients.

Clinical approaches to non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) ranges from simple steatosis to nonalcoholic steatohepatitis (NASH), leading to fibrosis and potentially cirrhosis, and it is one of the most common causes of liver disease worldwide. NAFLD is associated with other medical conditions such as metabolic syndrome, obesity, cardiovascular disease and diabetes. NASH can only be diagnosed through liver biopsy, but noninvasive techniques have been developed to identify patients who are most likely to have NASH or fibrosis, reducing the need for liver biopsy and risk to patients. Disease progression varies between individuals and is linked to a number of risk factors. Mechanisms involved in the pathogenesis are associated with diet and lifestyle, influx of free fatty acids to the liver from adipose tissue due to insulin resistance, hepatic oxidative stress, cytokines production, reduced very low-density lipoprotein secretion and intestinal microbiome. Weight loss through improved diet and increased physical activity has been the cornerstone therapy of NAFLD. Recent therapies such as pioglitazone and vitamin E have been shown to be beneficial. Omega 3 polyunsaturated fatty acids and statins may offer additional benefits. Bariatric surgery should be considered in morbidly obese patients. More research is needed to assess the impact of these treatments on a long-term basis. The objective of this article is to briefly review the diagnosis, management and treatment of this disease in order to aid clinicians in managing these patients.

The protective effects of different-time-ischemic preconditioning on the reperfusion injury in fatty livers in rats

BACKGROUND

The present study was aimed to investigate the protective effects of different-time-ischemic preconditioning on the reperfusion injury in fatty livers in rats, and to elucidate the mechanisms underlying the protective effects and the optimal safe ischemic preconditioning time on the hepatic IR injury in steatotic livers.

METHODOLOGY/PRINCIPAL FINDINGS

A rat fatty liver model was established by high-fat diet feeding. We investigated the changes in the concentration of AST, ALT, LDH and NO in the serum, and of MDA, SOD, and MPO in the liver samples in response to different ischemic preconditioning times and ischemia-reperfusion injury. Histological analysis was performed to evaluate the results of the hepatic fatty infiltration. 1) At 24 h after 15 min ischemic preconditioning with 10 min reperfusion (15 min +10 min IP), the extent and area of the necrosis was markedly higher in the fatty liver samples with respect to IR, compared to the normal liver samples. 2) In response to the treatment of 5/8 min +10 min IP, the fatty liver group showed lower levels of serological indicators and liver MDA and MPO compared to the other groups, while the SOD activity of the fatty liver group was significantly higher than the other groups (p<0.05). Compared to the corresponding IR group, all IP groups showed a significantly higher serum NO concentration (p<0.05). Among the fatty liver groups, the 5/8 min+10 min IP group showed the highest NO concentration (p<0.05).

CONCLUSIONS/SIGNIFICANCE

Fat infiltration could aggravate the ischemia-reperfusion injury in the rat liver. Furthermore, ischemic preconditioning could increase the tolerance of the fatty liver, which was induced by the high-fat diet, to hepatic ischemia-reperfusion injury in rats. The protocol of 5/8 min +10 min IP was the optimal regimen for the treatment of moderate and severe fatty livers.

Reduced heme oxygenase-1 expression in steatotic livers infected with hepatitis C virus

Hepatic nonalcoholic fatty liver disease (NAFLD) is known to exacerbate liver injury due to chronic hepatitis C infection. Heme oxygenase-1 (HO-1) is an important protective antioxidative defense enzyme that is known to be induced in response to NAFLD and other liver injuries. The aim of this study was to evaluate HO-1 expression in HCV infected human livers with concomitant NAFLD.

METHODS

We compared levels of HO-1 in NAFLD liver biopsies from patients with or without chronic HCV infection using immunohistochemistry, immunoblots and real time RT-PCR. We also evaluated frozen sections of liver with dihydroethidium (DHE) or dichlorofluorescein (DCF) fluorescence staining to evaluate O(2)(-) and peroxide production respectively.

RESULTS

HO-1 expression was only increased in NAFLD livers without HCV infection, while HCV infected livers showed reduced HO-1 levels, regardless whether NAFLD was present. In uninfected livers with NAFLD, HO-1 expression was primarily localized in hepatocytes containing fat and areas of injury around the central vein. However, both NAFLD with and without concomitant HCV infection showed high levels of O(2)(-) or peroxide production compared to normal human liver control samples.

CONCLUSIONS

These findings support the hypothesis that NAFLD is an important process for hepatocyte oxidative stress and injury in liver diseases. They also suggest that HCV can repress HO-1 induction in vivo even when other inducers of HO-1 are present.

Metformin and atorvastatin combination further protect the liver in type 2 diabetes with hyperlipidaemia

BACKGROUND

non-alcoholic fatty liver disease (NAFLD) and type 2 diabetes are associated with dyslipidaemia, inflammation and oxidative stress. However, the pathophysiology of NAFLD in type 2 diabetes with hyperlipidaemia is not fully known, as well as the utility of the commonly prescribed anti-diabetic and lipid-lowering drugs in ameliorating liver injury markers.

METHODS

hepatic complications of type 2 diabetes with hyperlipidaemia and the effects of atorvastatin and metformin, isolated and in association, in systemic and hepatic inflammatory and oxidative stress markers were tested using genetic type 2 diabetic Goto-Kakizaki rats fed with a high-fat diet.

RESULTS

the high-fat diet aggravated the overall metabolic state and the hepatic markers of injury. All treatments decreased fasting glycaemia, insulin resistance and free fatty acid levels. Combined treatment further decreased C-reactive protein (CRP), adiponectin, liver tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6), systemic and hepatic oxidative stress and portal inflammation.

CONCLUSIONS

our data provides evidence of a greater benefit with a combination of atorvastatin and metformin in improving liver injury in type 2 diabetes with hyperlipidaemia.

Effects of N-acetylcysteine on regeneration following partial hepatectomy in rats with nonalcoholic fatty liver disease

PURPOSE

To investigate the effect of N-acetylcysteine on regeneration following partial hepatectomy in rats with nonalcoholic fatty liver disease (NAFLD).

METHODS

N-Acetylcysteine was given to seven rats with NAFLD (group 1); physiological saline was given to seven rats with NAFLD (group 2); and physiological saline was given to seven rats with a normal liver (group 3). We performed two-thirds hepatectomy in all rats and removed the remnant liver tissue 48 h later to measure the mitotic index (MI), proliferating cell nuclear antigen, glutathione (GSH), and malondialdehyde (MDA) levels.

RESULTS

Mitotic index values were significantly higher in group 1 than in groups 2 and 3, and higher in group 3 than in group 2. Proliferating cell nuclear antigen values were significantly higher in group 1 than in group 2, but no significant difference was found in comparison with group 3. Glutathione values in group 1 were significantly higher than in group 2 and MDA values in group 1 were lower than in group 2. There was no significant difference between groups 1 and 3 in GSH and MDA values, in both the two-thirds hepatectomy and 48-h tissues.

CONCLUSIONS

N-Acetylcysteine enhanced regeneration after partial hepatectomy in rats with NAFLD. We believe that it exerted this effect through its influence on oxidative stress.

Effect of a lifestyle intervention in patients with abnormal liver enzymes and metabolic risk factors

BACKGROUND AND AIM

Non-alcoholic fatty liver disease associated with insulin resistance is the most common cause of abnormal liver tests in clinical practice. To date, practical and effective strategies to improve the metabolic profile of this large group of patients have not been well characterised. We sought to assess the effect at 3 months of a behavior change-based lifestyle intervention on the metabolic profile of patients characterised by elevated liver enzymes.

METHODS

A total of 152 patients with elevated liver enzymes, central obesity and a range of metabolic risk factors were randomised to either a moderate- (6 sessions/10 weeks) or low-intensity (3 sessions/4 weeks) lifestyle counselling intervention or control group.

RESULTS

There was improvement in all metabolic risk factors in the moderate-intensity group, versus a smaller number of changes in the low-intensity intervention group and no change in any metabolic risk factors in control subjects. Reduction in liver enzymes was greatest in the moderate-intensity intervention group and least in the control group. The likelihood of elevated alanine aminotransferase (ALT) levels in both the moderate and low-intensity groups was reduced by over 70% compared to controls. The proportion of subjects achieving weight loss (>or= 2%) was significantly higher in the moderate-intensity intervention group (66%) versus the low-intensity intervention group (39%; P < 0.05) and controls (29%; P < 0.001).

CONCLUSIONS

Moderate and even low-intensity lifestyle counselling interventions targeting improvement in physical activity and nutritional behaviors and modest weight loss are a practical and effective method for improving the health of patients with elevated liver enzymes and a range of metabolic risk factors.

The impact of diet on liver fibrosis and on response to interferon therapy in patients with HCV-related chronic hepatitis

BACKGROUND AND AIMS

A deranged metabolic status and alcohol intake may trigger induction and progression of chronic hepatitis C virus (HCV) liver disease. The aim of this study was to evaluate whether dietary composition affects the severity of liver damage and response to therapy in patients with HCV-related chronic hepatitis.

METHODS

We enrolled 1,084 patients with biopsy-proven HCV-related chronic hepatitis (432 treated with interferon plus ribavirin) and 2,326 healthy subjects in this prospective study conducted in a university hospital. Dietary habits were recorded in enrolled individuals, and their alcohol consumption was evaluated with a questionnaire (AUDIT). Body mass index, and plasma levels of blood glucose, nitrogen, creatinine, cholesterol, and triglycerides were also measured. All individuals underwent routine liver tests and HCV genotyping.

RESULTS

At study onset, there were no differences in metabolic status or alcohol consumption between patients and controls. About 50% of each group was overweight, and about 60% consumed alcohol. Patients and controls had similar dietary habits. Intake of carbohydrates, lipids and polyunsaturated fatty acids, and alcohol consumption were independent factors of liver damage at histology (logistic regression analysis). Some dietary components (unsaturated fatty acids, iron, zinc, vitamin A, and niacin) and alcohol intake differed significantly (P < 0.05 and P 0.01, respectively; univariate analysis) between responders and nonresponders to interferon therapy. Genotype, age, body mass index, steatosis, and fibrosis were independent predictors of therapy outcome (P < 0.02; multivariate analysis).

CONCLUSIONS

The severity of HCV-related chronic hepatitis depends on a variety of factors. Our results show that dietary composition is related to the extent of liver damage. Although traditional risk factors independently affected treatment response, some dietary components were associated with nonresponse to therapy in our patients. This suggests that HCV patients may benefit from instructions regarding their diet.

Mitochondrial dysfunction and oxidative stress in the pathogenesis of alcohol- and obesity-induced fatty liver diseases

Fatty liver disease associated with chronic alcohol consumption or obesity/type 2 diabetes has emerged as a serious public health problem. Steatosis, accumulation of triglyceride in hepatocytes, is now recognized as a critical "first-hit" in the pathogenesis of liver disease. It is proposed that steatosis "primes" the liver to progress to more severe liver pathologies when individuals are exposed to subsequent metabolic and/or environmental stressors or "second-hits." Genetic risk factors can also influence the susceptibility to and severity of fatty liver disease. Furthermore, oxidative stress, disrupted nitric oxide (NO) signaling, and mitochondrial dysfunction are proposed to be key molecular events that accelerate or worsen steatosis and initiate progression to steatohepatitis and fibrosis. This review article will discuss the following topics regarding the pathobiology and molecular mechanisms responsible for fatty liver disease: (1) the "two-hit" or "multi-hit" hypothesis, (2) the role of mitochondrial bioenergetic defects and oxidant stress, (3) the interplay between NO and mitochondria in fatty liver disease, (4) genetic risk factors and oxidative stress-responsive genes, and (5) the feasibility of antioxidants for treatment.

Relationship between nonalcoholic fatty liver disease prevalence and visceral fat in obese adolescents

BACKGROUND

Visceral adiposity is the major risk factor for paediatric nonalcoholic fatty liver disease.

AIMS

Determine the prevalence of nonalcoholic fatty liver disease according to the visceral fat quartile.

SUBJECTS

181 obese adolescents including 113 girls (16.58+/-1.56 years) and 68 boys (16.87+/-1.62 years) were evaluated.

METHODS

The inclusion criteria were obesity and post-pubertal stage of Tanner. Visceral fat of obese adolescents was distributed in quartiles after ultrasound nonalcoholic fatty liver disease diagnosis.

RESULTS

Nonalcoholic fatty liver disease prevalence was 45.30%. It was observed that 62.07% and 76.47% of girls and boys with nonalcoholic fatty liver disease were found in the 4th quartile. In a multivariate logistic analysis it was observed that only visceral fat remained statistically significant, every 1cm increase in visceral fat was associated with a 1.97 fold (95% CI 1.06-3.66) in boys and 2.08 fold (95% CI 1.38-3.13) in girls increased risk to develop nonalcoholic fatty liver disease. Indeed it was verified a positive correlation between visceral fat, body mass index, insulin levels, homeostasis model assessment insulin resistance index and steatosis degree.

CONCLUSIONS

Our findings suggested that the expansion of visceral fat was a determinant factor to increase nonalcoholic fatty liver disease prevalence and the visceral fat measured by ultrasound might be a good predictor to identify risk for nonalcoholic fatty liver disease in obese adolescents. It was confirmed by a stronger correlation between visceral fat and body mass index.

Endothelial dysfunction in Turkish patients with non-alcoholic fatty liver disease

BACKGROUND

The components of the metabolic syndrome are closely related with endothelial dysfunction, which is a pathophysiological issue of cardiovascular diseases. Non-alcoholic fatty liver disease (NAFLD) is considered as one of the components of the metabolic syndrome. The aim of this study was to evaluate the endothelial-dependent dilatation (EDD) and endothelial-independent dilatation (EID) of the brachial artery in NAFLD.

METHODS

Fifteen non-alcoholic steatohepatitis (NASH), 17 patients with simple steatosis and 16 healthy subjects formed the study group. Non-alcoholic fatty liver disease group was composed of patients admitted to the gastroenterology outpatient clinic because of increased liver enzymes. Endothelial functions of the brachial artery were evaluated by vascular ultrasound. EDD was assessed by establishing reactive hyperaemia, and EID was determined by using sublingual nitrate.

RESULTS

No statistical difference for the basal diameter of brachial artery was found between the groups (P = 0.49). The values for EDD and EID were significantly different across all three groups (P < 0.0001 and P < 0.0001, respectively). EDD and EID were significantly lower in NASH compared with simple steatosis (P = 0.01 and P < 0.01, respectively). However, there was no statistical significance for EDD and EID in simple steatosis groups compared with controls (P = 0.58 and P = 0.98, respectively).

CONCLUSIONS

Our study showed that patients with NASH had significantly worse endothelial dysfunction compared with patients with simple steatosis and healthy subjects. The treatment strategies with ameliorative effects for endothelial dysfunction might be effective for delaying the development of cardiovascular complications in NAFLD.