Rosiglitazone versus rosiglitazone and metformin versus rosiglitazone and losartan in the treatment of nonalcoholic steatohepatitis in humans: a 12-month randomized, prospective, open- label trial

Pharmacological interventions for non-alcoholic fatty liver disease: a systematic review and network meta-analysis

AIM

Several drugs have been used for treating non-alcoholic fatty liver disease (NAFLD). The present study is a network meta-analysis of such drugs.

DESIGN, SETTING AND PATIENTS

Randomised clinical trials comparing drug interventions in patients with NAFLD were analysed. OR and weighted mean difference (95 % CI) were the effect estimates for categorical and numerical outcomes, respectively. Random-effects model was used to generate pooled estimates. Surface under the cumulative ranking curve was used to rank the treatments.

MAIN OUTCOME MEASURES

Proportion of responders was the primary outcome measure and non-alcoholic steatohepatitis scores, liver enzymes, lipid profile, body mass index, homeostatic model assessment of insulin resistance, intrahepatic fat and adverse events were the key secondary outcomes.

RESULTS

116 studies were included in the systematic review and 106 in the meta-analysis. Elafibranor, gemfibrozil, metadoxine, obeticholic acid, pentoxifylline, pioglitazone, probiotics, telmisartan, vildagliptin and vitamin E significantly increased the response rate than standard of care. Various other drugs were observed to modify the secondary outcomes favourably. Probiotics was found with a better response in children; and elafibranor, obeticholic acid, pentoxifylline and pioglitazone in patients with type 2 diabetes mellitus. The quality of evidence observed was either low or very low.

CONCLUSION

In patients with NAFLD, several drugs have been shown to have variable therapeutic benefit. However, the estimates and the inferences should be considered with extreme caution as it might change with the advent of future head-to-head clinical trials.

Catalase and nonalcoholic fatty liver disease

Obesity and insulin resistance are considered the main causes of nonalcoholic fatty liver disease (NAFLD), and oxidative stress accelerates the progression of NAFLD. Free fatty acids, which are elevated in the liver by obesity or insulin resistance, lead to incomplete oxidation in the mitochondria, peroxisomes, and microsomes, leading to the production of reactive oxygen species (ROS). Among the ROS generated, H₂O₂ is mainly produced in peroxisomes and decomposed by catalase. However, when the H₂O₂ concentration increases because of decreased expression or activity of catalase, it migrates to cytosol and other organelles, causing cell injury and participating in the Fenton reaction, resulting in serious oxidative stress. To date, numerous studies have been shown to inhibit the pathogenesis of NAFLD, but treatment for this disease mainly depends on weight loss and exercise. Various molecules such as vitamin E, metformin, liraglutide, and resveratrol have been proposed as therapeutic agents, but further verification of the dose setting, clinical application, and side effects is needed. Reducing oxidative stress may be a fundamental method for improving not only the progression of NAFLD but also obesity and insulin resistance. However, the relationship between NAFLD progression and antioxidants, particularly catalase, which is most commonly expressed in the liver, remains unclear. Therefore, this review summarizes the role of catalase, focusing on its potential therapeutic effects in NAFLD progression.

The effect of antidiabetic medications on non-alcoholic fatty liver disease (NAFLD)

Non-alcoholic fatty liver disease (NAFLD) is the hepatic manifestation of the metabolic syndrome and is prevalent in more than 50% of patients with type II diabetes. At present, there is no approved therapy for NASH. Until now, the only proven effective interventions in improving biochemical and histological features of NASH, including fibrosis, are weight loss and physical activity even without weight loss. Because of the common epidemiological and pathophysiological features between NAFLD and T2DM, many antidiabetics drugs have been tested in patients with NAFLD over the years. Among these, pioglitazone and liraglutide seem to improve some histological features of NASH but have no clear effect on fibrosis. Metformin has been largely studied in the past years without convincing evidence of improving NAFLD. Data on other compounds such as DDP-4 and SGLT-2 inhibitors are limited. The rational and results of such studies are discussed in the present review.

The Association between Angiotensin II Type 1 Receptor Gene A1166C Polymorphism and Non-alcoholic Fatty Liver Disease and Its Severity

BACKGROUND Genetic predisposition may have important role in pathogenesis of non-alcoholic fatty liver disease (NAFLD). Angiotensin II type I receptor (AGTR1) has been known to involve in the process of liver steatosis and fibrosis. This study aimed to investigate the association between AGTR1 A1166C polymorphism and NAFLD. METHODS A cross-sectional study was conducted during May 2014-May 2015 among healthy adults referring to our radiology clinic for abdominal sonography. AGTR1 A1166C polymorphism was evaluated in subjects with NAFLD and healthy individuals using allelic discrimination method. RESULTS 58 subjects with NAFLD were compared with 88 healthy individuals without NAFLD. The frequency of AA and CC genotypes of AGTR1 was significantly higher in patients with NAFLD compared with controls (p = 0.029 and 0.042, respectively). C allele was more detected in subjects with NAFLD compared with the healthy controls (OR: 2.1; 95% CI: 1.23-3.61, p = 0.006). CC genotype (OR: 10.62; 95% CI: 1.05-106.57, p = 0.045) and C allele (OR: 6.81; 95% CI: 1.42- 32.48, p = 0.016) were also predictors of severe fatty liver disease in our study population. CONCLUSION Our results provide the first evidence that AGTR1 gene A1166C polymorphism not only is associated with NAFLD and but also may predict its severity.

Renin-angiotensin system inhibition ameliorates CCl4-induced liver fibrosis in mice through the inactivation of nuclear transcription factor kappa B

Therapeutic interventions for liver fibrosis are still limited due to the complicated molecular pathogenesis. Renin-angiotensin system (RAS) seems to contribute to the development of hepatic fibrosis. Therefore, we aimed to examine the effect of RAS inhibition on CCl₄-induced liver fibrosis. Mice were treated with silymarin (30 mg·kg^-1), perindopril (1 mg·kg^-1), fosinopril (2 mg·kg^-1), or losartan (10 mg·kg^-1). The administration of RAS inhibitors improved liver histology and decreased protein expression of alpha smooth muscle actin (α-SMA) and hepatic content of hydroxyproline. These effects found to be mediated via inactivation of nuclear transcription factor kappa B (NFκB) pathway by the inhibition of NFκB p65 phosphorylation at the Ser536 residue and phosphorylation-induced degradation of nuclear factor kappa-B inhibitor alpha (NFκBia) subsequently inhibited NFκB-induced TNF-α and TGF-β1, leading to lower levels of tissue inhibitor of metalloproteinase-1 (TIMP-1) and vascular endothelial growth factor (VEGF). We concluded that the tissue affinity of the angiotensin converting enzyme inhibitors (ACEIs) has no impact on its antifibrotic activity and that interfering the RAS either through the inhibition of ACE or the blockade of AT1R has the same therapeutic benefit. These results suggest RAS inhibitors as promising candidates for further clinical trials in the management of hepatic fibrosis.

Clinical application of angiotensin receptor blockers in patients with non-alcoholic fatty liver disease: a systematic review and meta-analysis

Objective

Non-alcoholic fatty liver disease (NAFLD) is one of the most common chronic liver diseases, ranging from simple steatosis to progressive steatohepatitis and cirrhosis. Because of their anti-inflammatory and anti-fibrotic effects, angiotensin receptor blockers (ARBs) are potential therapeutic agents for NAFLD. The present systematic review assessed the effectiveness of ARBs in NAFLD management.

Results

Accounting for data overlap and exclusion criteria, randomized controlled trial -based and single-arm meta-analyses were conducted for four studies with 362 patients and eight studies with 525 patients, respectively. Although alanine aminotransferase levels were not significantly affected by ARB treatment (standardized mean difference 0.20; 95% confidence interval (CI) [−0.04, 0.44]; P = 0.10), a fixed-effect model revealed a decreasing trend in alanine transaminase levels. Low-density lipoprotein levels were reduced by ARB treatment (MD 5.21; 95% CI [3.01, 7.40]; P < 0.00001), and total cholesterol also decreased in response to ARBs (MD 2.10; 95% CI [−0.37, 4.57]; P = 0.10). However, the fibrosis score and NAFLD activity score were not significantly improved by ARB treatment (MD 0.10; 95% CI [−0.58, 0.78]; P = 0.77) (MD −0.25; 95% CI [−1.05, 0.55]; P = 0.53).

Materials and Methods

Keywords were used to identify studies in PubMed, EMBASE, CENTRAL, Web of Science and CNKI published up to July 31, 2017. Single-arm and RCT-based meta-analyses of the available data were performed using RevMan (version 5.3).

Conclusions

Although ARBs significantly decreased plasma low-density lipoprotein and total cholesterol levels, the current evidence is insufficient to support the efficacy of ARBs in managing fibrosis in NAFLD patients.

Treating nonalcoholic fatty liver disease in patients with type 2 diabetes mellitus: a review of efficacy and safety

OBJECTIVE

To review current literature for the efficacy and safety of treatment for nonalcoholic fatty liver disease (NAFLD) in patients with type 2 diabetes mellitus (T2DM).

DATA SOURCES

A PubMed literature search from January 1990 to June 2017 was conducted using the search terms nonalcoholic fatty liver disease, diabetes mellitus, type 2, therapy, treatment, treat, therapeutics, nonalcoholic fatty liver, nonalcoholic hepatosteatosis, NASH, NAFLD, metformin, and statin. Bibliographies of chosen articles were reviewed.

STUDY SELECTION AND DATA EXTRACTION

Relevant articles on metformin, thiazolidinediones (TZD), glucagon-like peptide-1 receptor agonists (GLP-1 RA), and statins for the treatment of NAFLD which included patients with T2DM were reviewed. A total of 23 relevant studies were found and included randomized controlled, observational, and open-label designs, as well as three meta-analyses.

DATA SYNTHESIS

Metformin combined with weight loss provides a modest improvement in steatosis and no improvement in fibrosis in patients with NAFLD and T2DM. TZDs showed positive results on fibrosis and resolution of NASH but at least half of patients studied were nonresponders. GLP-1 RAs also showed favorable results on reductions in transaminases and steatosis and improvements in insulin sensitivity and weight loss but lack efficacy data for resolution of NASH or improvement in fibrosis scores. Statins showed favorable results on reductions in transaminases but mixed results for improvement in steatosis and fibrosis scores.

CONCLUSION

All reviewed treatment options are safe for management of NAFLD in patients with T2DM but long-term histological improvements are minimal. TZDs are efficacious for resolution of NASH and improvements in fibrosis but long-term use is required to maintain these results.

Current and emerging pharmacological therapy for non-alcoholic fatty liver disease

The main treatment of patients with non-alcoholic fatty liver disease (NAFLD) is life style modification including weight reduction and dietary regimen. Majority of patients are safely treated with this management and pharmacologic interventions are not recommended. However, a subgroup of NAFLD patients with non-alcoholic steatohepatitis (NASH) who cannot achieve goals of life style modification may need pharmacological therapy. One major obstacle is measurement of histological outcome by liver biopsy which is an invasive method and is not recommended routinely in these patients. Several medications, mainly targeting baseline mechanism of NAFLD, have been investigated in clinical trials for treatment of NASH with promising results. At present, only pioglitazone acting as insulin sensitizing agent and vitamin E as an anti-oxidant have been recommended for treatment of NASH by international guidelines. Lipid lowering agents including statins and fibrates, pentoxifylline, angiotensin receptor blockers, ursodeoxycholic acid, probiotics and synbiotics are current agents with beneficial effects for treatment of NASH but have not been approved yet. Several emerging medications are in development for treatment of NASH. Obeticholic acid, liraglutide, elafibranor, cenicriviroc and aramchol have been tested in clinical trials or are completing trials. Here in, current and upcoming medications with promising results in clinical trial for treatment of NAFLD were reviewed.

Pharmacotherapy of nonalcoholic steatohepatitis: Reflections on the existing evidence

Pharmacotherapy for nonalcoholic fatty liver disease (NAFLD) has not yet been approved by the US Food and Drug Administration. Over the past decade, a large number of clinical studies have explored the safety and efficacy of different drugs in treating nonalcoholic steatohepatitis (NASH), including diet pills, antioxidants, insulin sensitizers, lipid-lowering agents, anti-inflammatory cytokines, cytoprotective agents and intestinal probiotics. Based on the evidence from randomized controlled trials a number of academic groups have developed guidelines for the diagnosis and management of NAFLD and NASH. In this article, we discussed the current situation of NASH pharmacotherapy.

Review article: new treatments in non-alcoholic fatty liver disease

BACKGROUND

Non-alcoholic fatty liver disease is the fastest growing cause of liver disease in the Western world, yet there is no approved pharmacotherapy. While lifestyle modifications remain the mainstay of treatment, only a proportion of individuals are able to make or sustain them, and so more treatment options are required.

AIM

To review the potential benefit of drugs used in clinical practice, those entering phase II trials, and compounds being investigated in pre-clinical studies.

METHODS

A literature search was performed using PubMed to identify relevant studies; linked references were also reviewed.

RESULTS

Vitamin E and pioglitazone have shown efficacy in non-alcoholic steatohepatitis (NASH), but long-term safety concerns, specifically bladder cancer and osteoporosis with pioglitazone, have limited their use. GLP-1 analogues and SGLT-2 inhibitors are currently approved for use in diabetes, have shown early efficacy in NASH and also have beneficial cardiovascular effects. Peroxisome proliferator-activator receptors and FXR agonists have potent effects on lipogenesis, inflammation and fibrosis, respectively, with their efficacy and safety being currently tested in phase 3. As inflammation and apoptosis are key features of NASH agents modulating these pathways are of interest; CCR2/5 antagonists downregulate inflammatory pathways and reduce fibrosis with caspase and apoptosis signal-regulating kinase 1 inhibitors reducing apoptosis and fibrosis.

CONCLUSIONS

Rising demand and an improved understanding of NASH pathophysiology has led to a surge in development of new therapies. Tailoring pharmacotherapy to the dominant pathogenic pathway in a given patient along with use of combination therapy is likely to represent the future direction in treatment of patients with NASH.

Safety, Tolerability, and Preliminary Efficacy of the Anti-Fibrotic Small Molecule PRI-724, a CBP/β-Catenin Inhibitor, in Patients with Hepatitis C Virus-related Cirrhosis: A Single-Center, Open-Label, Dose Escalation Phase 1 Trial

Background

There is currently no anti-fibrotic drug therapy available to treat hepatitis C virus (HCV) cirrhosis. The aim of this study was to assess the safety, tolerability, and anti-fibrotic effect of PRI-724, a small-molecule modulator of Wnt signaling, in patients with HCV cirrhosis.

Methods

In this single-center, open-label, phase 1 trial, we sequentially enrolled patients with HCV cirrhosis who were classified as Child-Pugh (CP) class A or B. PRI-724 was administered as a continuous intravenous infusion of 10, 40, or 160 mg/m²/day for six cycles of 1 week on and 1 week off. The primary endpoints were frequency and severity of adverse events. The secondary endpoint was efficacy of PRI-724 in treating cirrhosis based on CP score and liver biopsy. This study is registered with ClinicalTrials.gov (no. NCT02195440).

Findings

Between Sept 3, 2014 and May 2, 2016, 14 patients were enrolled: CP class A:B, 6:8; median age, 62 (range: 43 to 74) years; male:female, 10:4. Twelve of the 14 patients completed six cycles of treatment; one was withdrawn from the study due to possible study drug-related liver injury (grade 3) in the 160 mg/m²/day dose cohort and one withdrew for personal reasons. Serious adverse events occurred in three patients [21% (3/14)], one of which was possibly related to PRI-724. The most common adverse events were nausea [29% (4/14)] and fatigue [21% (3/14)].

After PRI-724 administration, the CP scores worsened by 1 point in two patients in the 10 mg/m²/day cohort, improved in three patients at 1, 1, and 2 points in the 40 mg/m²/day cohort, and improved in one patient by 3 points in the 160 mg/m²/day cohort. The histology activity index scores of the liver tissue improved in two patients and exacerbated in two patients in the 10 mg/m²/day cohort, and improved in one patient in the 40 mg/m²/day cohort.

Interpretation

This study showed that administration of 10 or 40 mg/m²/day intravenous PRI-724 over 12 weeks was well-tolerated by patients with HCV cirrhosis; however, liver injury as a possible related serious adverse event was observed in the 160 mg/m²/day cohort.

Funding Source

AMED.

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Safety, tolerability, pharmacokinetics, and anti-fibrotic effect of PRI-724 were assessed in patients with HCV cirrhosis.

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PRI-724 was well tolerated, suggesting that the treatment is relatively safe against HCV liver cirrhosis.

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Significant fibrosis reduction in hepatic lobules 12 weeks after PRI-724 treatment (40 mg/m²/day) in 3 CP class B patients.

Liver cirrhosis is one of the leading causes of morbidity and mortality in developed countries and is the 14th most common cause of death in adults worldwide. However, there is currently no anti-fibrotic drug therapy available to treat hepatitis C virus (HCV) cirrhosis. This study showed that intravenous PRI-724 at 10 or 40 mg/m²/day over 12 weeks was well-tolerated by patients with HCV cirrhosis and resulted in an improvement of liver histology and CP class in several patients.

Randomized trial comparing the effects of gliclazide, liraglutide, and metformin on diabetes with non-alcoholic fatty liver disease

BACKGROUND

The aim of the present study was to compare the effects of gliclazide, liraglutide, and metformin in type 2 diabetes mellitus (T2DM) patients with non-alcoholic fatty liver disease (NAFLD).

METHODS

Eighty-seven subjects were randomized to receive liraglutide, metformin, or gliclazide for 24 weeks. Primary outcomes included HbA1c levels, intrahepatic fat (IHF) content, and liver function.

RESULTS

Both HbA1c levels and IHF content were reduced after treatment in all three groups. However, HbA1c levels were lower in the liraglutide- and metformin-treated groups than in the gliclazide-treated group, and reductions in IHF content were greater with liraglutide than with gliclazide. Liraglutide and metformin treatments reduced weight and improved liver function. Changes in IHF content were positively correlated with reductions in serum alanine aminotransferase and triglyceride levels, as well as weight. At 24 weeks, reductions in IHF content were greater in subjects with weight loss ≥5%, changes in waistline ≤0 cm (including decreases in waistline), HbA1c reductions ≥2.5%, and HbA1c levels <6.5%.

CONCLUSIONS

In T2DM patients with NAFLD, compared with liraglutide and metformin, gliclazide resulted in less improvement in liver function, reductions in IHF content and HbA1c levels, and less weight loss; in addition, slightly better improvements were achieved with liraglutide than with metformin.

Mouse models of nonalcoholic steatohepatitis in preclinical drug development

Nonalcoholic fatty liver disease (NAFLD) has become the most common cause of chronic liver disease in the Western world. NAFLD is a complex spectrum of liver diseases ranging from benign hepatic steatosis to its more aggressive necroinflammatory manifestation, nonalcoholic steatohepatitis (NASH). NASH pathogenesis is multifactorial and risk factors are almost identical to those of the metabolic syndrome. This has prompted substantial efforts to identify novel drug therapies for correcting underlying metabolic deficits, and to prevent or alleviate hepatic fibrosis in NASH. Available mouse models of NASH address different aspects of the disease, have varying clinical translatability, and, therefore, also show different utility in drug discovery.

Novel Anti-fibrotic Therapies

Fibrosis is a major player in cardiovascular disease, both as a contributor to the development of disease, as well as a post-injury response that drives progression. Despite the identification of many mechanisms responsible for cardiovascular fibrosis, to date no treatments have emerged that have effectively reduced the excess deposition of extracellular matrix associated with fibrotic conditions. Novel treatments have recently been identified that hold promise as potential therapeutic agents for cardiovascular diseases associated with fibrosis, as well as other fibrotic conditions. The purpose of this review is to provide an overview of emerging antifibrotic agents that have shown encouraging results in preclinical or early clinical studies, but have not yet been approved for use in human disease. One of these agents is bone morphogenetic protein-7 (BMP7), which has beneficial effects in multiple models of fibrotic disease. Another approach discussed involves altering the levels of micro-RNA (miR) species, including miR-29 and miR-101, which regulate the expression of fibrosis-related gene targets. Further, the antifibrotic potential of agonists of the peroxisome proliferator-activated receptors will be discussed. Finally, evidence will be reviewed in support of the polypeptide hormone relaxin. Relaxin is long known for its extracellular remodeling properties in pregnancy, and is rapidly emerging as an effective antifibrotic agent in a number of organ systems. Moreover, relaxin has potent vascular and renal effects that make it a particularly attractive approach for the treatment of cardiovascular diseases. In each case, the mechanism of action and the applicability to various fibrotic diseases will be discussed.

Pharmacological evaluation of pioglitazone and candesartan cilexetil in a novel mouse model of non-alcoholic steatohepatitis, modified choline-deficient, amino acid-defined diet fed low-density lipoprotein receptor knockout mice

AIM

Low-density lipoprotein receptor knockout (LDLR-KO) mice fed a modified choline-deficient and amino acid-defined (mCDAA) diet show non-alcoholic steatohepatitis (NASH)-like pathophysiology. In order to pharmacologically benchmark this model, effects of pioglitazone (a thiazolidinedione) and candesartan cilexetil (an angiotensin II type 1 receptor blocker) on steatosis and liver fibrosis were examined.

METHODS

Pioglitazone (10 mg/kg) and candesartan cilexetil (3 mg/kg) were given orally once daily to LDLR-KO mice under mCDAA diet for 7 weeks. Blood biochemistry and hepatic histology were assessed, and hepatic gene expression levels and triglyceride content were measured.

RESULTS

Pioglitazone suppressed hepatic COL1A1 gene expression by 43% and attenuated hepatic fibrosis areas by 49%. Pioglitazone also decreased plasma alanine aminotransferase levels, liver weight, hepatic triglyceride content, and hepatic expression of other fibrosis-related genes such as TGFB1, SPP1, TIMP1, and IL6. Candesartan cilexetil suppressed hepatic COL1A1 gene expression by 33%, whereas the other end-points including hepatic fibrosis areas were not affected.

CONCLUSIONS

Pioglitazone showed anti-fibrotic effects accompanied by improving hepatic transaminase activity and hepatic lipid accumulation, but the effect of candesartan cilexetil was only limited, unlike previous reports for angiotensin II type 1 receptor blockers. As the pharmacological effects of pioglitazone in the current animal model are similar to those reported in patients with NASH, this model may represent some aspects of the pathophysiology of NASH. Further profiling using other agents or mechanisms that have been tested in the clinic will better clarify the utility of the animal model.

PPARs and nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) encompasses a range of liver pathology ranging from simple steatosis to varying degrees of inflammation, hepatocyte injury and fibrosis. Without intervention it can progress to end-stage liver disease and hepatocellular carcinoma. Given its close association with obesity, the prevalence of NAFLD has increased dramatically worldwide. Currently, there are no FDA-approved medications for the treatment of NAFLD and although lifestyle modifications with appropriate diet and exercise have been shown to be beneficial, this has been difficult to achieve and sustain for the majority of patients. As such, the search for effective therapeutic agents is an active area of research. Peroxisome proliferator-activated receptors (PPARs) belong to a class of nuclear receptors. Because of their key role in the transcriptional regulation of mediators of glucose and lipid metabolism, PPAR ligands have been investigated as possible therapeutic agents. Here we review the current evidence from preclinical and clinical studies investigating the therapeutic potential of PPAR ligands for the treatment of NAFLD.

A randomised controlled trial of losartan as an anti-fibrotic agent in non-alcoholic steatohepatitis

Introduction

Non-alcoholic fatty liver disease (NAFLD) is a common liver disease worldwide. Experimental and small clinical trials have demonstrated that angiotensin II blockers (ARB) may be anti-fibrotic in the liver. The aim of this randomised controlled trial was to assess whether treatment with Losartan for 96 weeks slowed, halted or reversed the progression of fibrosis in patients with non-alcoholic steatohepatitis (NASH).

Methods

Double-blind randomised-controlled trial of Losartan 50 mg once a day versus placebo for 96 weeks in patients with histological evidence of NASH. The primary outcome for the study was change in histological fibrosis stage from pre-treatment to end-of-treatment.

Results

The study planned to recruit 214 patients. However, recruitment was slower than expected, and after 45 patients were randomised (median age 55; 56% male; 60% diabetic; median fibrosis stage 2), enrolment was suspended. Thirty-two patients (15 losartan and 17 placebo) completed follow up period: one patient (6.7%) treated with losartan and 4 patients (23.5%) in the placebo group were “responders” (lower fibrosis stage at follow up compared with baseline). The major reason for slow recruitment was that 39% of potentially eligible patients were already taking an ARB or angiotensin converting enzyme inhibitor (ACEI), and 15% were taking other prohibited medications.

Conclusions

Due to the widespread use of ACEI and ARB in patients with NASH this trial failed to recruit sufficient patients to determine whether losartan has anti-fibrotic effects in the liver.

Trial registration

ISRCTN 57849521

Current and future treatment options in non-alcoholic steatohepatitis (NASH)

Non-alcoholic steatohepatitis (NASH) is a chronic liver disease that can progress to cirrhosis and hepatocellular carcinoma. Diagnosis of NASH requires a liver biopsy and is defined as presence of hepatic steatosis, ballooning and lobular inflammation with or without fibrosis. Although NASH is the most common cause of liver disease in the west world and among the top three indications for liver transplantation, there are no universally accepted pharmacological therapies and therapeutic advances have been slow. Areas covered: Current evidence about lifestyle interventions, bariatric surgery and pharmacotherapy is reviewed. Dietary recommendations and lifestyle interventions have shown promising results but are difficult to maintain. At the moment, there is no universally approved medical treatment for NASH. Pioglitazone and vitamin E are recommended by guidelines in selected patients. An increasing number of phase II and III trials in non-cirrhotic NASH are currently recruiting and their preliminary results discussed. Expert commentary: As NASH is classified as a medical condition of an unmet therapeutic need, it has gained an accelerated access pathway for drug approval based on surrogate endpoints. It is therefore expected that within the next five years, there will be at least one approved agent for the pharmacological treatment of pre-cirrhotic NASH.

Pharmacological interventions for non-alcohol related fatty liver disease (NAFLD): an attempted network meta-analysis

BACKGROUND

Non-alcohol related fatty liver disease (commonly called non-alcoholic fatty liver disease (NAFLD)) is liver steatosis in the absence of significant alcohol consumption, use of hepatotoxic medication, or other disorders affecting the liver such as hepatitis C virus infection, Wilson's disease, and starvation. NAFLD embraces the full spectrum of disease from pure steatosis (i.e. uncomplicated fatty liver) to non-alcoholic steatohepatitis (NASH), via NASH-cirrhosis to cirrhosis. The optimal pharmacological treatment for people with NAFLD remains uncertain.

OBJECTIVES

To assess the comparative benefits and harms of different pharmacological interventions in the treatment of NAFLD through a network meta-analysis and to generate rankings of the available pharmacological treatments according to their safety and efficacy. However, it was not possible to assess whether the potential effect modifiers were similar across different comparisons. Therefore, we did not perform the network meta-analysis, and instead, assessed the comparative benefits and harms of different interventions using standard Cochrane methodology.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, Science Citation Index Expanded, the World Health Organization International Clinical Trials Registry Platform, and ClinicalTrials.com to August 2016.

SELECTION CRITERIA

We included only randomised clinical trials (irrespective of language, blinding, or publication status) in participants with NAFLD. We excluded trials which included participants who had previously undergone liver transplantation. We considered any of the various pharmacological interventions compared with each other or with placebo or no intervention.

DATA COLLECTION AND ANALYSIS

We calculated the odds ratio (OR) and rate ratio with 95% confidence intervals (CI) using both fixed-effect and random-effects models based on an available participant analysis with Review Manager. We assessed risk of bias according to the Cochrane risk of bias tool, controlled risk of random errors with Trial Sequential Analysis, and assessed the quality of the evidence using GRADE.

MAIN RESULTS

We identified 77 trials including 6287 participants that met the inclusion criteria of this review. Forty-one trials (3829 participants) provided information for one or more outcomes. Only one trial was at low risk of bias in all domains. All other trials were at high risk of bias in one or more domains. Overall, all the evidence was very low quality. Thirty-five trials included only participants with non-alcohol related steatohepatitis (NASH) (based on biopsy confirmation). Five trials included only participants with diabetes mellitus; 14 trials included only participants without diabetes mellitus. The follow-up in the trials ranged from one month to 24 months.We present here only the comparisons of active intervention versus no intervention in which two or more trials reported at least one of the following outcomes: mortality at maximal follow-up, serious adverse events, and health-related quality of life, the outcomes that determine whether a treatment should be used. Antioxidants versus no interventionThere was no mortality in either group (87 participants; 1 trial; very low quality evidence). None of the participants developed serious adverse events in the trial which reported the proportion of people with serious adverse events (87 participants; 1 trial; very low quality evidence). There was no evidence of difference in the number of serious adverse events between antioxidants and no intervention (rate ratio 0.89, 95% CI 0.36 to 2.19; 254 participants; 2 trials; very low quality evidence). None of the trials reported health-related quality of life. Bile acids versus no interventionThere was no evidence of difference in mortality at maximal follow-up (OR 5.11, 95% CI 0.24 to 107.34; 659 participants; 4 trials; very low quality evidence), proportion of people with serious adverse events (OR 1.56, 95% CI 0.84 to 2.88; 404 participants; 3 trials; very low quality evidence), or the number of serious adverse events (rate ratio 1.01, 95% CI 0.66 to 1.54; 404 participants; 3 trials; very low quality evidence) between bile acids and no intervention. None of the trials reported health-related quality of life. Thiazolidinediones versus no interventionThere was no mortality in either group (74 participants; 1 trial; very low quality evidence). None of the participants developed serious adverse events in the two trials which reported the proportion of people with serious adverse events (194 participants; 2 trials; very low quality evidence). There was no evidence of difference in the number of serious adverse events between thiazolidinediones and no intervention (rate ratio 0.25, 95% CI 0.06 to 1.05; 357 participants; 3 trials; very low quality evidence). None of the trials reported health-related quality of life. Source of fundingTwenty-six trials were partially- or fully-funded by pharmaceutical companies that would benefit, based on the results of the trial. Twelve trials did not receive any additional funding or were funded by parties with no vested interest in the results. The source of funding was not provided in 39 trials.

AUTHORS' CONCLUSIONS

Due to the very low quality evidence, we are very uncertain about the effectiveness of pharmacological treatments for people with NAFLD including those with steatohepatitis. Further well-designed randomised clinical trials with sufficiently large sample sizes are necessary.

Salidroside Modulates Insulin Signaling in a Rat Model of Nonalcoholic Steatohepatitis

A growing body of evidence has shown the beneficial effects of salidroside in cardiovascular and metabolic diseases. This study aimed to evaluate the therapeutic effects of salidroside on nonalcoholic steatohepatitis (NASH) in rats and explore the underlying mechanisms related to insulin signaling. A rat model of NASH was developed by high-fat diet for 14 weeks. From week 9 onward, the treatment group received oral salidroside (4.33 mg/kg) daily for 6 weeks. Salidroside effectively attenuated steatosis and vacuolation of hepatic tissue, with a dramatic decrease in liver triglycerides and free fatty acid levels (P < 0.01). Dysregulation of FINS, FBG, HOMA-IR, ALT, and AST in serum was ameliorated with salidroside treatment (P < 0.01). In the liver, salidroside induced significant increases in key molecules in the insulin signaling pathway, such as phosphorylated insulin receptor substrate 1 (IRS1), phosphoinositide 3-kinase (PI3K), and protein kinase B (PKB), with a significant decrease in SREBP-1c levels (P < 0.01). Therefore, salidroside effectively protected rats from high-fat-diet-induced NASH, which may be partially attributed to its effects on the hepatic insulin signaling pathway.

Management of Nonalcoholic Fatty Liver Disease in Patients With Type 2 Diabetes: A Call to Action

Traditionally a disease of hepatologists, nonalcoholic fatty liver disease (NAFLD) has recently become a major concern for a broad spectrum of health care providers. Endocrinologists and those caring for patients with type 2 diabetes mellitus (T2DM) are at center stage, as T2DM appears to worsen the course of NAFLD and the liver disease makes diabetes management more challenging. However, the nature of this relationship remains incompletely understood. Although the increasing prevalence of NAFLD is frequently attributed to the epidemic of obesity and is often oversimplified as the "hepatic manifestation of the metabolic syndrome," it is a much more complex disease process that may also be observed in nonobese individuals and in patients without clinical manifestations of the metabolic syndrome. It carries both metabolic and liver-specific complications that make its approach unique among medical conditions. Diabetes appears to promote the development of nonalcoholic steatohepatitis (NASH), the more severe form of the disease, and increases the risk of cirrhosis and hepatocellular carcinoma. Patients and physicians face many uncertainties, including fragmented information on the natural history of the disease, challenges in the diagnosis of NASH, and few pharmacological agents with proven efficacy. However, recent advances in diagnosis and treatment, combined with the risk of serious consequences from inaction, call for health care providers to be more proactive in the management of patients with T2DM and NASH.

NAFLD and diabetes mellitus

The liver constitutes a key organ in systemic metabolism, contributing substantially to the development of insulin resistance and type 2 diabetes mellitus (T2DM). The mechanisms underlying these processes are not entirely understood, but involve hepatic fat accumulation, alterations of energy metabolism and inflammatory signals derived from various cell types including immune cells. Lipotoxins, mitochondrial function, cytokines and adipocytokines have been proposed to play a major part in both NAFLD and T2DM. Patients with NAFLD are commonly insulin resistant. On the other hand, a large number of patients with T2DM develop NAFLD with its inflammatory complication, NASH. The high incidence of NASH in patients with T2DM leads to further complications, such as liver cirrhosis and hepatocellular carcinoma, which are increasingly recognized. Therapeutic concepts such as thiazolidinediones (glitazones) for treating T2DM also show some efficacy in the treatment of NASH. This Review will describe the multifaceted and complex interactions between the liver and T2DM.

PPARs and Mitochondrial Metabolism: From NAFLD to HCC

Metabolic related diseases, such as type 2 diabetes, metabolic syndrome, and nonalcoholic fatty liver disease (NAFLD), are widespread threats which bring about a significant burden of deaths worldwide, mainly due to cardiovascular events and cancer. The pathogenesis of these diseases is extremely complex, multifactorial, and only partially understood. As the main metabolic organ, the liver is central to maintain whole body energetic homeostasis. At the cellular level, mitochondria are the metabolic hub connecting and integrating all the main biochemical, hormonal, and inflammatory signaling pathways to fulfill the energetic and biosynthetic demand of the cell. In the liver, mitochondria metabolism needs to cope with the energetic regulation of the whole body. The nuclear receptors PPARs orchestrate lipid and glucose metabolism and are involved in a variety of diseases, from metabolic disorders to cancer. In this review, focus is placed on the roles of PPARs in the regulation of liver mitochondrial metabolism in physiology and pathology, from NAFLD to HCC.

Foetal programming by methyl donor deficiency produces steato-hepatitis in rats exposed to high fat diet

Non-alcoholic steatohepatitis (NASH) is a manifestation of metabolic syndrome, which emerges as a major public health problem. Deficiency in methyl donors (folate and vitamin B12) during gestation and lactation is frequent in humans and produces foetal programming effects of metabolic syndrome, with small birth weight and liver steatosis at day 21 (d21), in rat pups. We investigated the effects of fetal programming on liver of rats born from deficient mothers (iMDD) and subsequently subjected to normal diet after d21 and high fat diet (HF) after d50. We observed increased abdominal fat, ASAT/ALAT ratio and angiotensin blood level, but no histological liver abnormality in d50 iMDD rats. In contrast, d185 iMDD/HF animals had hallmarks of steato-hepatitis, with increased markers of inflammation and fibrosis (caspase1, cleaved IL-1β, α1(I) and α2(I) collagens and α-SMA), insulin resistance (HOMA-IR and Glut 2) and expression of genes involved in stellate cell stimulation and remodelling and key genes triggering NASH pathomechanisms (transforming growth factor beta super family, angiotensin and angiotensin receptor type 1). Our data showed a foetal programming effect of MDD on liver inflammation and fibrosis, which suggests investigating whether MDD during pregnancy is a risk factor of NASH in populations subsequently exposed to HF diet.

Strong antineoplastic effects of metformin in preclinical models of liver carcinogenesis

Studies suggest that metformin, widely used for treating Type 2 diabetes, possesses innate antineoplastic properties. For metabolic syndrome patients with hepatocellular carcinoma (HCC), metformin may provide antitumoral effects. We evaluated the impact of metformin on tumour growth and visceral fat composition using relevant preclinical models of metabolic syndrome. Studies were performed in three hepatoma cell lines, in HepG2 xenograft mice fed with standard chow (SC) diet, 60% high-fat diet (HFD) or 30% fructose diet (FR), and an ex vivo model of human cultured HCC slices. Visceral fatty acid composition was analysed by magnetic resonance imaging (MRI). Metformin had a dose-dependent inhibitory effect on cell proliferation and apoptosis in vitro through the deregulation of mTOR/AMPK, AKT and extracellular signal regulated kinase (ERK) signalling pathways. Tumour engraftment rates were higher in HFD mice than SC mice (hepatic: 79% compared with 25%, P=0.02) and FR mice (subcutaneous: 86% compared with 50%, P=0.04). Subcutaneous tumour volume was increased in HFD mice (+64% compared with FR and SC, P=0.03). Metformin significantly decreased subcutaneous tumour growth via cell-cycle block and mammalian target of rapamycin (mTOR) pathway inhibition, and also induced hypoxia and decreased angiogenesis. In ex vivo tumour slices, metformin treatment led to increased necrosis, decreased cyclin D1 and increased carbonic anhydrase-9 (CA-9). Metformin caused qualitative changes in visceral fat composition of HFD mice, with decreased proportions of polyunsaturated fatty acids (14.6% ± 2.3% compared with 17.9% ± 3.0%, P=0.04). The potent antitumoral effects of metformin in multiple preclinical models implicating several molecular mechanisms provide a strong rationale for clinical trials including combination studies in HCC patients.

Renin-Angiotensin System Inhibitors, Type 2 Diabetes and Fibrosis Progression: An Observational Study in Patients with Nonalcoholic Fatty Liver Disease

BACKGROUND

The clinical determinants of fibrosis progression in nonalcoholic fatty liver disease (NAFLD) are still under definition.

AIM

To assess the clinical determinants of fibrosis progression rate (FPR) in NAFLD patients with baseline and follow-up histological evaluation, with a special focus on the impact of pharmacological therapy.

METHODS

In an observational cohort of 118 Italian patients from tertiary referral centers, liver histology was evaluated according to Kleiner. Independent predictors of FPR were selected by a stepwise regression approach.

RESULTS

Median follow-up was 36 months (IQR 24-77). Twenty-five patients (18%) showed some amelioration, 63 (53%) had stability, 30 (25%) had progression of fibrosis. Patients with nonalcoholic steatohepatitis (NASH) had similar demographic and anthropometric features, but a higher prevalence of type 2 diabetes (T2D; p = 0.010), and use of renin-angiotensin axis system (RAS) inhibitors (p = 0.005). Fibrosis progression was dependent of the length of follow-up, and was associated with, but did not require, the presence of NASH (p<0.05). Both fibrosis progression and faster FPR were independently associated with higher APRI score at follow-up, absence of treatment with RAS inhibitors, and T2D diagnosis at baseline (p<0.05). There was a significant interaction between use of RAS inhibitors and T2D on FPR (p = 0.002). RAS inhibitors were associated with slower FPR in patients with (p = 0.011), but not in those without (p = NS) T2D.

CONCLUSIONS

NASH is not required for fibrosis progression in NAFLD, whereas T2D seems to drive fibrogenesis independently of hepatic inflammation. Use of RAS inhibitors may contrast fibrosis progression especially in high-risk patients affected by T2D.

Pharmacological management of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) affects one-third of the population and two-thirds of patients with obesity or type 2 diabetes (T2DM). Its more aggressive form is known as nonalcoholic steatohepatitis (NASH) and is characterized by hepatocyte necrosis, inflammation and often fibrosis. The presence of fibrosis indicates a more aggressive course and may lead to cirrhosis. Premature mortality in NASH is related to both hepatic (cirrhosis and hepatocellular carcinoma) and extra-hepatic complications, largely cardiovascular disease (CVD). Many therapeutic agents have been tested, but still none approved specifically for NASH. Treatment of NAFLD includes aggressive management of diabetes and cardiovascular risk factors, although the role of controlling hyperglycemia per se in patients with T2DM and NASH remains unknown. Agents tested with some success in non-diabetic patients with NASH include pioglitazone, liraglutide, vitamin E and to a lesser degree, pentoxiphylline. In patients with T2DM and NASH only pioglitazone has shown to significantly improve liver histology, with only a handful of patients with diabetes having been studied with other modalities. This review focuses on available agents for NASH to assist clinicians in the management of these complex patients. Many novel compounds are being studied and will likely make combination therapy for NASH a reality in the future.

Comparative efficacy of interventions on nonalcoholic fatty liver disease (NAFLD): A PRISMA-compliant systematic review and network meta-analysis

BACKGROUND

The prevalence of nonalcoholic fatty liver disease (NAFLD) has significantly increased over the last decades. Despite existence of several interventions, there remains unclear which interventions work the best.

METHODS

A systematic review and network meta-analysis of randomized trials comparing efficacy of all treatment options in NAFLD were performed to determine comparative efficacy and safety of interventions in the management of NAFLD. Several electronic databases were searched up to Nov 15, 2015. Outcomes include liver histological outcomes (i.e., fibrosis), all-cause mortality, cirrhosis, and safety. A network meta-analysis was applied to estimate pooled risk ratios (RR). Quality of evidence was assessed using GRADE criteria.

RESULTS

A total of 44 studies (n = 3802) were eligible. When compared with placebo, obeticholic acid (OCA) was the only intervention that significantly improved fibrosis with RR (95% CI) of 1.91 (1.15, 3.16), while pentoxyfylline (PTX) demonstrated improved fibrosis without statistical significance with RR (95% CI) of 2.27 (0.81, 6.36). Only thiazolidinedione (TZD) and vitamin E use resulted in significant increase in resolution of NASH, while OCA, TZD, and vitamin E significantly improved other outcomes including NAS, steatosis, ballooning, and inflammation outcomes. Quality of evidence varied from very low (i.e., metformin, PTX on mean change of ballooning grade) to high (OCA, TZD, vitamin E on improving histological outcomes). Limitations of this study were lack of relevant long-term outcomes (e.g., cirrhosis, death, safety), possible small study effect, and few head-to-head studies.

CONCLUSIONS

Our study suggests potential efficacy of OCA, TZD, and vitamin E in improving histologic endpoints in NAFLD. These findings are however based on a small number of studies. Additional studies are awaited to strengthen this network meta-analysis.

Biopsy and Noninvasive Methods to Assess Progression of Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) comprises a spectrum of histopathologic features, ranging from isolated hepatic steatosis, to steatohepatitis with evidence of hepatocellular injury and fibrosis, to cirrhosis. The diagnosis and determination of NAFLD prognosis requires clinical and histopathologic assessments. Liver biopsy still is regarded as the reference for differentiating steatosis (NAFL) from nonalcoholic steatohepatitis, for staging hepatic fibrosis, and for identifying NAFLD in patients with other chronic liver disease. Standardized grading and staging histologic scoring systems, such as the NAFLD activity score and the steatosis, activity, and fibrosis score, can help guide clinical decisions and assess outcomes of clinical trials. Improved understanding of the pathophysiology of NAFLD and technologic advances have led to algorithms that can be used to assess serum biomarkers and imaging methods that are noninvasive alternatives to biopsy collection and analysis. We review the advantages and limitations of biopsy analysis and noninvasive tests as diagnostic and prognostic tools for patients with NAFLD. We also discuss techniques to improve dynamic histopathology assessment, and emerging blood and imaging biomarkers of fibrogenesis.

Non-alcoholic steatohepatitis and liver transplantation

Non-alcoholic steatohepatitis is a growing liver-related health problem. In Europe, non-alcoholic fatty liver disease is the most usual reason of chronic liver illness while steatohepatitis, its progressive form, affects 1% of Europeans and North Americans. In the United States steatohepatitis-related cirrhosis is one of the main indications for liver transplant. A targeted stratification for patients waiting for transplant and affected by this disease is mandatory especially because of their increased cardiovascular and cancer risk. The adequate treatment of NAFLD is crucial for the reduction of the disease related morbidity and mortality. In post-transplant setting, the recurrent or de novo steatosis might seriously affect the allograft short- and long-term outcome. Many conditions can represent the basis of the post-transplant steatohepatitis: obesity, hyperlipidaemia, diabetes mellitus, arterial hypertension, immunosuppressant treatment, alcoholic habit and liver graft steatosis. Today, the only consolidated therapy is represented by a deep life-style intervention since the use of drug-based alternative strategies is still limited and a very few data are available for the post-transplant period. Targeted and personalized behaviour and pharmacological interventions have to be developed for both the pre- and post-transplant phase.

Histological Assessment of NAFLD

Nonalcoholic fatty liver disease (NAFLD) covers a spectrum of histological lesions ranging from steatosis to a complex pattern with hepatocyte injury and inflammation in an appropriate clinical context. The disease has been artificially dichotomized into NAFL (steatosis) and NASH (steatosis with hepatocellular injury and inflammation), but it is increasingly clear that intermediate patterns may exist. More than NASH, the stage of fibrosis was shown to govern prognosis, and for such evaluation, a liver biopsy of adequate size and width is needed. Like for any other chronic liver diseases, semi-quantitative histologic scores have been proposed. They are not useful in clinical practice but concur to categorize homogeneous group of patients according to their histology. Pediatric NAFLD is a growing concern. While a subgroup of children may harbor different but characteristic histological patterns, most of them display a mixed pattern or features similar to the adults. Today, liver histology is the mainstay for clinical trials. Biopsy is used both for enrollment and for assessing benefit of clinical trials. End points such as reversion of NASH or regression of fibrosis are acceptable but require a clear histological definition.

Emerging Therapies for Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease is the most common cause of liver disease in the United States. There are no drug therapies approved for the treatment of nonalcoholic steatohepatitis (NASH). Multiple different pathways are involved in the pathogenesis and each can be the target of the therapy. It is possible that more than 1 target is involved in disease development and progression. Multiple clinical trials with promising agents are underway. Because NASH is a slowly progressive disease and treatment likely to be of prolonged duration, acceptance and approval of any agent will require information on long-term clinical benefits and safety.

The Metabolic Syndrome and Its Influence on Nonalcoholic Steatohepatitis

Nonalcoholic steatohepatitis (NASH) and the metabolic syndrome (MetS) are highly prevalent in the Western population. Their pathogenesis is closely linked to insulin resistance, which serves as a therapeutic target for the management of these conditions. This review article reviews the research supporting the influence of MetS on NASH and includes studies supporting their similar epidemiology, pathogenesis, and treatment.

Dual Outcomes of Rosiglitazone Treatment on Fatty Liver

In previous studies, it has been reported that rosiglitazone has opposing effects on nonalcoholic fatty liver disease. The purpose of the current study is to test the hypothesis that such opposing effects are related to different levels of peroxisome proliferator-activated receptor gamma (PPAR-γ) in the liver. Using a gene transfer approach and mice fed a high-fat diet (HFD) as an animal model, we demonstrate that mice with low levels of PPAR-γ expression in the liver are resistant to HFD-induced development of fatty liver when treated with rosiglitazone. Conversely, rosiglitazone treatment actually exacerbates liver steatosis in obese mice that have a higher level of PPAR-γ. Mechanistic studies show that an elevated hepatic PPAR-γ level is associated with an increased expression of genes responsible for lipid metabolism in the liver, particularly Cd36, Fabp4, and Mgat1. The concurrent transfer of these three genes into the mouse liver fully recapitulates the phenotypic change induced by the overexpression of PPAR-γ. These results provide evidence in support of the importance of PPAR-γ in the liver when rosiglitazone is considered for the treatment of fatty liver disease. Clinically, our results suggest the necessity of verifying PPAR-γ levels in the liver when rosiglitazone is considered as a treatment option, and indicate that the direct use of rosiglitazone for treatment of nonalcoholic fatty liver may not be desirable when the patient's PPAR-γ level in the liver is significantly elevated.

The Role of Nuclear Receptors in the Pathophysiology, Natural Course, and Drug Treatment of NAFLD in Humans

Nonalcoholic fatty liver disease (NAFLD) describes steatosis, nonalcoholic steatohepatitis with or without fibrosis, and hepatocellular carcinoma, namely the entire alcohol-like spectrum of liver disease though observed in the nonalcoholic, dysmetabolic, individual free of competing causes of liver disease. NAFLD, which is a major public health issue, exhibits intrahepatic triglyceride storage giving rise to lipotoxicity. Nuclear receptors (NRs) are transcriptional factors which, activated by ligands, are master regulators of metabolism and also have intricate connections with circadian control accounting for cyclical patterns in the metabolic fate of nutrients. Several transcription factors, such as peroxisome proliferator-activated receptors, liver X receptors, farnesoid X receptors, and their molecular cascades, finely regulate energetic fluxes and metabolic pathways. Dysregulation of such pathways is heavily implicated in those metabolic derangements characterizing insulin resistance and metabolic syndrome and in the histogenesis of progressive NAFLD forms. We review the role of selected NRs in NAFLD pathogenesis. Secondly, we analyze the role of NRs in the natural history of human NAFLD. Next, we discuss the results observed in humans following administration of drug agonists or antagonists of the NRs pathogenically involved in NAFLD. Finally, general principles of treatment and lines of research in human NAFLD are briefly examined.

A Comprehensive Updated Review of Pharmaceutical and Nonpharmaceutical Treatment for NAFLD

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease in the western world with prevalence of 20–33%. NAFLD comprises a pathological spectrum. Nonalcoholic fatty liver (NAFL) is at one end and consists of simple hepatic steatosis. On the contrary, nonalcoholic steatohepatitis (NASH) consists of steatosis, inflammation, and ballooning degeneration and can progress to cirrhosis. Despite the rising incidence, definitive treatment for NAFLD, specifically NASH, has not yet been established. Lifestyle modification with dietary changes combined with regular aerobic exercise, along with multidisciplinary approach including cognitive behavior therapy, has been shown to be an effective therapeutic option, even without a significant weight loss. Pioglitazone and vitamin E have shown to be most effective in NASH patients. Surgery and weight loss medication are effective means of weight loss but can potentially worsen NASH related fibrosis. Other agents such as n-3 polyunsaturated fatty acids, probiotics, and pentoxifylline along with herbal agent such as milk thistle as well as daily intake of coffee have shown potential benefits, but further well organized studies are definitely warranted. This review focuses on the available evidence on pharmaceutical and nonpharmaceutical therapy in the treatment and the prevention of NAFLD, primarily NASH.

Comparative effectiveness of pharmacological interventions for nonalcoholic steatohepatitis: A systematic review and network meta-analysis

We performed a Bayesian network meta-analysis combining direct and indirect treatment comparisons to assess the comparative effectiveness of pharmacological agents for the treatment of nonalcoholic steatohepatitis (NASH). Through systematic literature review, we identified nine randomized, controlled trials (RCTs) including 964 patients with biopsy-proven NASH, comparing vitamin E, thiazolidinediones (TZDs), pentoxifylline, or obeticholic acid to one another or placebo. The primary outcome was improvement in fibrosis stage; secondary outcomes were improvement in ballooning degeneration, lobular inflammation, and steatosis. We reported relative risks (RRs) and 95% confidence intervals (CIs) from direct meta-analysis and 95% credible intervals (CrIs) from Bayesian network meta-analysis, and used Grading of Recommendations Assessment, Development and Evaluation (GRADE) criteria to appraise quality of evidence. Moderate-quality evidence supports the use of pentoxifylline (RR, 0.26; 95% CrI: 0.05-1.00) and obeticholic acid (RR, 0.81; 95% CI: 0.70-0.95) over placebo in improving fibrosis. High-quality evidence supports the effect of vitamin E, TZDs, and obeticholic acid over placebo in improving ballooning degeneration. All four interventions seemed to have at least moderate-quality evidence over placebo to improve steatosis. Moderate-quality evidence supports that TZDs, pentoxifylline, and obeticholic acid decrease lobular inflammation. All the head-to-head comparisons were supported by very-low-quality evidence except for superiority of TZDs over vitamin E on improving steatosis and lobular inflammation, which had moderate-quality evidence.

CONCLUSIONS

Based on direct and network meta-analysis, pentoxifylline and obeticholic acid improve fibrosis, and vitamin E, TZDs, and obeticholic acid improve ballooning degeneration in patients with NASH. Future comparative trials of combination therapies targeting distinct histological features are warranted.

Liver fibrosis: Common mechanisms and antifibrotic therapies

Liver fibrosis and in particular cirrhosis have become major endpoints in clinical trials of patients with chronic liver diseases. Here, viral hepatitis, alcoholic and non-alcoholic steatohepatitis have become the major etiologies. We have made great progress in our understanding of the mechanisms and the cell biology of liver fibrosis and have already made the transition from preclinical testing of antifibrotic agents and strategies towards clinical translation. There continues to be an urgent need for specific antifibrotic therapies, despite the advent of highly potent antiviral agents that can even induce regression of advanced fibrosis. This review addresses central mechanisms and cells to be targeted, current antifibrotic drug trials, and the state of non-invasive biomarker development that is key to rapid clinical progress and to a personalized treatment of fibrosis.

Nonalcoholic steatohepatitis: emerging targeted therapies to optimize treatment options

Diet and lifestyle changes have led to worldwide increases in the prevalences of obesity and metabolic syndrome, resulting in substantially greater incidence of nonalcoholic fatty liver disease (NAFLD). NAFLD is considered a hepatic manifestation of metabolic syndrome and is related to diabetes, insulin resistance, central obesity, hyperlipidemia, and hypertension. Nonalcoholic steatohepatitis (NASH) is an entity that describes liver inflammation due to NAFLD. Growing evidence suggests that NAFLD is a multisystem disease with a clinical burden that is not only confined to liver-related morbidity and mortality, but that also affects several extra-hepatic organs and regulatory pathways. Thus, NAFLD is considered an important public health issue, but there is currently no effective therapy for all NAFLD patients in the general population. Studies seeking optimal therapy for NAFLD and NASH have not yet led to development of a universal protocol for treating this growing problem. Several pharmacological agents have been studied in an effort to improve insulin resistance and the proinflammatory mediators that may be responsible for NASH progression. Cardiovascular risk factors are highly prevalent among NASH patients, and the backbone of treatment regimens for these patients still comprises general lifestyle interventions, including dietary changes and increased physical activity. Vitamin E and thiazolidinedione derivatives are currently the most evidence-based therapeutic options, but only limited clinical evidence is available regarding their long-term efficacy and safety. Vitamin D and renin-angiotensin-aldosterone system blockers are promising drugs that are currently being intensively investigated for use in NAFLD/NASH patients.

Pharmacotherapy for Nonalcoholic Fatty Liver Disease

Lifestyle modifications and optimization of the management of cardiometabolic comorbidities are currently the mainstay of treatment for patients with nonalcoholic fatty liver disease. Pharmacotherapy to halt or reverse hepatic histological injury and prevent the development of end-stage liver disease is specifically offered to patients with nonalcoholic steatohepatitis (NASH) and those with advanced fibrosis. In this review, the authors discuss the state of the art of various pharmacological agents for NASH. The efficacy of vitamin E and pioglitazone is reasonably well established in a selected group of patients with NASH. Current data do not offer convincing evidence for efficacy of pentoxifylline, long-chain polyunsaturated fatty acids, angiotensin receptor blockers, metformin, or ursodeoxycholic acid. They also discuss the state of several emerging agents for treating NASH including the farsenoid X receptor ligand, obeticholic acid.

Nonalcoholic fatty liver disease: new treatments

PURPOSE OF REVIEW

Nonalcoholic fatty liver disease is the most common cause of liver dysfunction in the western world because of its close association with obesity, insulin resistance and dyslipidaemia. Nonalcoholic steatohepatitis (NASH) is a particular health concern due to the increased morbidity and mortality associated with progressive disease. At present, without specific targeted pharmacological therapies, the mainstay of therapy remains weight loss through dietary modification and lifestyle change; thus, the purpose of this review is to summarize the recent evidence for current and emerging therapies in NASH.

RECENT FINDINGS

Some existing medications, including pioglitazones and angiotensin receptor antagonists, may be repurposed to help treat this condition. Vitamin E may improve histology in NASH, but safety issues limit its use. Recently, a number of novel agents specifically targeting nonalcoholic fatty liver disease pathogenesis have entered clinical trials, including the farnesoid X receptor agonist obeticholic acid, which has shown significant histological improvements in steatohepatitis and fibrosis.

SUMMARY

Diet/lifestyle modification remains the mainstay of treatment. For patients with NASH and advanced fibrosis, current liver-directed pharmacotherapy with vitamin E and pioglitazone offer some benefits; obeticholic acid appears promising and is currently being tested. Comorbidities must be diagnosed and treated; cardiovascular disease remains a primary cause of death in these patients.

Antifibrotic therapies in the liver

Significant progress has been made in understanding the principles underlying the development of liver fibrosis. This includes appreciating its dynamic nature, the importance of active fibrolysis in fibrosis regression, and the plasticity of cell populations endowing them with fibrogenic or fibrolytic properties. This is complemented by an increasing array of therapeutic targets with known roles in the progression or regression of fibrosis. With a key role for fibrosis in determining clinical outcomes and encouraging data from recently Food and Drug Administration-approved antifibrotics for pulmonary fibrosis, the development and validation of antifibrotic therapies has taken center stage in translational hepatology. In addition to summarizing the recent progress in antifibrotic therapies, the authors discuss some of the challenges ahead, such as achieving a better understanding of the interindividual heterogeneity of the fibrotic response, how to match interventions with the ideal patient population, and the development of better noninvasive methods to assess the dynamics of fibrogenesis and fibrolysis. Together, these advances will permit a better targeting and dose titration of individualized therapies. Finally, the authors discuss combination therapy with different antifibrotics as possibly the most potent approach for treating fibrosis in the liver.

Current pharmacological therapies for nonalcoholic fatty liver disease/nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease (NAFLD)/nonalcoholic steatohepatitis (NASH) is considered to be a hepatic manifestation of metabolic syndrome, and its incidence is rapidly increasing worldwide. It is currently the most common chronic liver disease. NASH can progress to liver cirrhosis and hepatocellular carcinoma, and may result in liver-related death. Currently, the principal treatment for NAFLD/NASH is lifestyle modification by diet and exercise. However, pharmacological therapy is indispensable because obese patients with NAFLD often have difficulty maintaining improved lifestyles. The pathogenesis of NAFLD/NASH has not been completely elucidated. However, insulin resistance, inflammatory cytokines, and oxidative stress are thought to be important in the development and/or progression of the disease. Currently, insulin sensitizers (thiazolidinediones) and antioxidants (vitamin E) seem to be the most promising therapeutic agents for NAFLD/NASH, and lipid-lowering drugs, pentoxifylline, angiotensin receptor blockers, and n-3 polyunsaturated fatty acids also have promise. However, there is a lack of consensus regarding the most effective and appropriate pharmacotherapy for NAFLD/NASH. Animal experiments suggest that herbal medicines and natural products may be promising therapeutic agents for NAFLD/NASH, but their efficacy and safety are yet to be investigated in human studies. In this paper, we review the existing and potential pharmacological therapies for NAFLD/NASH.

Hepatic fibrosis: Concept to treatment

Understanding the molecular mechanisms underlying liver fibrogenesis is fundamentally relevant to developing new treatments that are independent of the underlying etiology. The increasing success of antiviral treatments in blocking or reversing the fibrogenic progression of chronic liver disease has unearthed vital information about the natural history of fibrosis regression, and has established important principles and targets for antifibrotic drugs. Although antifibrotic activity has been demonstrated for many compounds in vitro and in animal models, none has been thoroughly validated in the clinic or commercialized as a therapy for fibrosis. In addition, it is likely that combination therapies that affect two or more key pathogenic targets and/or pathways will be needed. To accelerate the preclinical development of these combination therapies, reliable single target validation is necessary, followed by the rational selection and systematic testing of combination approaches. Improved noninvasive tools for the assessment of fibrosis content, fibrogenesis and fibrolysis must accompany in vivo validation in experimental fibrosis models, and especially in clinical trials. The rapidly changing landscape of clinical trial design for liver disease is recognized by regulatory agencies in the United States (FDA) and Western Europe (EMA), who are working together with the broad range of stakeholders to standardize approaches to testing antifibrotic drugs in cohorts of patients with chronic liver diseases.