Long-term efficacy of rosiglitazone in nonalcoholic steatohepatitis: results of the fatty liver improvement by rosiglitazone therapy (FLIRT 2) extension trial

Diagnosis and management of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in Western industrialised countries. The prevalence of NAFLD is increasing in parallel with the global rise in obesity and type 2 diabetes mellitus. NAFLD represents a spectrum of liver disease severity. NAFLD begins with accumulation of triacylglycerols in the liver (steatosis), and is defined by hepatic fatty infiltration amounting to greater than 5% by liver weight or the presence of over 5% of hepatocytes loaded with large fat vacuoles. In almost a quarter of affected individuals, steatosis progresses with the development of liver inflammation to non-alcoholic steatohepatitis (NASH). NASH is a potentially progressive liver condition and with ongoing liver injury and cell death can result in fibrosis. Progressive liver fibrosis may lead to the development of cirrhosis in a small proportion of patients. With the growing prevalence of NAFLD, there is an increasing need for a robust, accurate and non-invasive approach to diagnosing the different stages of this condition. This review will focus on (1) the biochemical tests and imaging techniques used to diagnose the different stages of NAFLD; and (2) a selection of the current management approaches focusing on lifestyle interventions and pharmacological therapies for NAFLD.

Rates of and Factors Associated With Placebo Response in Trials of Pharmacotherapies for Nonalcoholic Steatohepatitis: Systematic Review and Meta-analysis

BACKGROUND & AIMS

It is important to know the extent of the placebo effect in designing randomized controlled trials for patients with nonalcoholic steatohepatitis (NASH), to accurately calculate sample size and define treatment endpoints.

METHODS

We performed a systematic review and meta-analysis of the placebo groups from randomized controlled trials of adults with NASH that provided histologic and/or magnetic resonance image-based assessments. We identified trials through a comprehensive search of MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Scopus, from each database's inception through January 2, 2018.

RESULTS

We identified 39 randomized controlled trials, comprising 1463 patients who received placebo. Histologic assessment data (the nonalcoholic fatty liver disease activity scores, NAS) were available from 956 patients; magnetic resonance spectroscopy data were available from 295 patients and magnetic resonance proton density fat fraction measurements from 61 patients. Overall, 25% of patients given placebo had an improvement in NAS by 2 or more points (95% CI, 21%-29%) with a small amount of heterogeneity (I₂ = 27%). There were improvements by at least 1 point in steatosis scores of 33% ± 3% of patients, in hepatocyte ballooning scores of 30% ± 3% of patients, in lobular inflammation scores of 32% ± 3% of patients, and in fibrosis scores of 21% ± 3% of patients, with a moderate amount of heterogeneity among trials (I₂ range, 51%-63%). Patients given placebo had a statistically significant improvement in NAS (by 0.72 ± 0.19), with a large amount of heterogeneity (I₂ = 96%). Univariate and multivariate meta-regression showed that trials with a higher baseline NAS, those conducted in South America, and those in which patients had a decrease in body mass index, were associated with greater improvements in NAS among patients given placebo. Patients given placebo had significant reductions in intrahepatic triglyceride, measured by magnetic resonance spectroscopy (by 1.45% ± 0.54%) with moderate heterogeneity (I₂ = 40%), and in magnetic resonance proton density fat fraction (by 2.43 ± 0.89), without heterogeneity (I₂ = 0). Mean serum levels of alanine and aspartate aminotransferases decreased significantly (by 11.7 ± 3.8 U/L and 5.9 ± 2.1 U/L, respectively; P < .01 for both).

CONCLUSIONS

In a meta-analysis of randomized controlled trials of NASH, patients given placebo have significant histologic, radiologic, and biochemical responses. The placebo response should be considered in designing trials of agents for treatment of NASH.

Drug-induced liver injury in obesity and nonalcoholic fatty liver disease

Obesity is commonly associated with nonalcoholic fatty liver (NAFL), a benign condition characterized by hepatic lipid accumulation. However, NAFL can progress in some patients to nonalcoholic steatohepatitis (NASH) and then to severe liver lesions including extensive fibrosis, cirrhosis and hepatocellular carcinoma. The entire spectrum of these hepatic lesions is referred to as nonalcoholic fatty liver disease (NAFLD). The transition of simple fatty liver to NASH seems to be favored by several genetic and environmental factors. Different experimental and clinical investigations showed or suggested that obesity and NAFLD are able to increase the risk of hepatotoxicity of different drugs. Some of these drugs may cause more severe and/or more frequent acute liver injury in obese individuals whereas others may trigger the transition of simple fatty liver to NASH or may worsen hepatic lipid accumulation, necroinflammation and fibrosis. This review presents the available information regarding drugs that may cause a specific risk in the context of obesity and NAFLD. These drugs, which belong to different pharmacological classes, include acetaminophen, halothane, methotrexate, rosiglitazone and tamoxifen. For some of these drugs, experimental investigations confirmed the clinical observations and unveiled different pathophysiological mechanisms which may explain why these pharmaceuticals are particularly hepatotoxic in obesity and NAFLD. Because obese people often take several drugs for the treatment of different obesity-related diseases, there is an urgent need to identify the main pharmaceuticals that may cause acute liver injury on a fatty liver background or that may enhance the risk of severe chronic liver disease.

Targeting mitochondria to oppose the progression of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is a condition characterized by the excessive accumulation of triglycerides in hepatocytes. NAFLD is the most frequent chronic liver disease in developed countries, and is often associated with metabolic disorders such as obesity and type 2 diabetes. NAFLD definition encompasses a spectrum of chronic liver abnormalities, ranging from simple steatosis (NAFL), to steatohepatitis (NASH), significant liver fibrosis, cirrhosis, and hepatocellular carcinoma. NAFLD, therefore, represents a global public health issue. Mitochondrial dysfunction occurs in NAFLD, and contributes to the progression to the necro-inflammatory and fibrotic form (NASH). Disrupted mitochondrial function is associated with a decrease in the energy levels and impaired redox balance, and negatively affects cell survival by altering overall metabolism and subcellular trafficking. Such events reduce the tolerance of hepatocytes towards damaging hits, and favour the injurious effects of extra-cellular factors. Here, we discuss the role of mitochondria in NAFLD and focus on potential therapeutic approaches aimed at preserving mitochondrial function.

A role of peroxisome proliferator-activated receptor γ in non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease is becoming a major health burden, as prevalence increases and there are no approved treatment options. Thiazolidinediones target the nuclear receptor peroxisome proliferator-activated receptor γ (PPARγ) and have been investigated in several clinical trials for their potential in treating non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH). PPARγ has specialized roles in distinct tissues and cell types, and although the primary function of PPARγ is in adipose tissue, where the highest expression levels are observed, hepatic expression levels of PPARγ are significantly increased in patients with NAFLD. Thus, NAFLD patients receiving treatment with PPARγ agonists might have a liver response apart from the one in adipose tissue. Owing to the different roles of PPARγ, new treatment strategies include development of compounds harnessing the beneficial effects of PPARγ while restricting PPARγ unwanted effects such as adipogenesis resulting in weight gain. Furthermore, dual or pan agonists targeting two or more of the PPARs have shown promising results in pre-clinical research and some are currently proceeding to clinical trials. This MiniReview explores adipose- and liver-specific actions of PPARγ, and how this knowledge may contribute in the search for new treatment modalities in NAFLD/NASH.

The Future of Nonalcoholic Fatty Liver Disease Treatment

Nonalcoholic Fatty Liver Disease (NAFLD) is the most common cause of chronic liver disease in the United States. The NAFLD subtype, nonalcoholic steatohepatitis, represents a progressive form of the disease that can lead to cirrhosis, portal hypertension, and hepatocellular carcinoma. NAFLD is a diagnosis of exclusion and is strongly related to obesity and the metabolic syndrome. Although there has been an explosion of exciting therapeutic avenues for NAFLD in recent years, the bedrock of management continues to be lifestyle modification, weight loss, and optimization of metabolic risk factors.

Effective Food Ingredients for Fatty Liver: Soy Protein β-Conglycinin and Fish Oil

Obesity is prevalent in modern society because of a lifestyle consisting of high dietary fat and sucrose consumption combined with little exercise. Among the consequences of obesity are the emerging epidemics of hepatic steatosis and nonalcoholic fatty liver disease (NAFLD). Sterol regulatory element-binding protein-1c (SREBP-1c) is a transcription factor that stimulates gene expression related to de novo lipogenesis in the liver. In response to a high-fat diet, the expression of peroxisome proliferator-activated receptor (PPAR) γ2, another nuclear receptor, is increased, which leads to the development of NAFLD. β-Conglycinin, a soy protein, prevents NAFLD induced by diets high in sucrose/fructose or fat by decreasing the expression and function of these nuclear receptors. β-Conglycinin also improves NAFLD via the same mechanism as for prevention. Fish oil contains n-3 polyunsaturated fatty acids such as eicosapentaenoic acid and docosahexaenoic acid. Fish oil is more effective at preventing NAFLD induced by sucrose/fructose because SREBP-1c activity is inhibited. However, the effect of fish oil on NAFLD induced by fat is controversial because fish oil further increases PPARγ2 expression, depending upon the experimental conditions. Alcohol intake also causes an alcoholic fatty liver, which is induced by increased SREBP-1c and PPARγ2 expression and decreased PPARα expression. β-Conglycinin and fish oil are effective at preventing alcoholic fatty liver because β-conglycinin decreases the function of SREBP-1c and PPARγ2, and fish oil decreases the function of SREBP-1c and increases that of PPARα.

Pharmacotherapy of type 2 diabetes in patients with chronic liver disease: focus on nonalcoholic fatty liver disease

INTRODUCTION

Pharmacotherapy used to treat type 2 diabetes mellitus (T2DM) is facing a paradigm shift in clinical practice with recent cardiovascular (CV) outcome trials having a substantial impact on drug prescription with treatment having a more tailored approach. In patients with T2DM, the issue of chronic liver disease is multifaceted. However, a clinical evidence is emerging on the beneficial effect of antidiabetic medications on nonalcoholic fatty liver disease (NAFLD).

AREAS COVERED

The authors provide a synopsis on the current and upcoming pharmacotherapy for NAFLD, including the challenges with their development, focusing on drugs for T2DM. Clinical data on the potential benefits and safety issues are assessed with the aim of proposing an individualized algorithm for patient management. Both MEDLINE and ClinicalTrials.Gov are used to derive the relevant information.

EXPERT OPINION

Considering the pivotal role of insulin resistance in NAFLD, insulin sensitizers should be the treatment of choice. Accordingly, pioglitazone is the only drug with a significant effect on liver fibrosis, the driver of disease progression and long-term outcome. Among new glucose-lowering drugs, glucagon-like-peptide 1 receptor agonists or sodium-glucose cotransporter type 2 inhibitors have shown positive effects in phase II studies and are qualifying as potential candidates for NAFLD treatment in diabetes.

Non-proteolytic ubiquitin modification of PPARγ by Smurf1 protects the liver from steatosis

Nonalcoholic fatty liver disease (NAFLD) is characterized by abnormal accumulation of triglycerides (TG) in the liver and other metabolic syndrome symptoms, but its molecular genetic causes are not completely understood. Here, we show that mice deficient for ubiquitin ligase (E3) Smad ubiquitin regulatory factor 1 (Smurf1) spontaneously develop hepatic steatosis as they age and exhibit the exacerbated phenotype under a high-fat diet (HFD). Our data indicate that loss of Smurf1 up-regulates the expression of peroxisome proliferator-activated receptor γ (PPARγ) and its target genes involved in lipid synthesis and fatty acid uptake. We further show that PPARγ is a direct substrate of Smurf1-mediated non-proteolytic lysine 63 (K63)-linked ubiquitin modification that suppresses its transcriptional activity, and treatment of Smurf1-deficient mice with a PPARγ antagonist, GW9662, completely reversed the lipid accumulation in the liver. Finally, we demonstrate an inverse correlation of low SMURF1 expression to high body mass index (BMI) values in human patients, thus revealing a new role of SMURF1 in NAFLD pathogenesis.

Treating Hepatic Steatosis and Fibrosis by Modulating Mitochondrial Pyruvate Metabolism

A hepatic comorbidity of metabolic syndrome, known as nonalcoholic fatty liver disease (NAFLD), is increasing in prevalence in conjunction with the pandemics of obesity and diabetes. The spectrum of NAFLD ranges from simple hepatic fat accumulation to a more severe disease termed nonalcoholic steatohepatitis (NASH), involving inflammation, hepatocyte death, and fibrosis. Importantly, NASH is linked to a much higher risk of cirrhosis, liver failure, and hepatocellular carcinoma, as well as an increased risk for nonhepatic malignancies and cardiovascular disease. Interest in the understanding of the disease processes and search for treatments for the spectrum of NAFLD-NASH has increased exponentially, but there are no approved pharmacologic therapies. In this review, we discuss the existing literature supporting insulin-sensitizing thiazolidinedione compounds as potential drug candidates for the treatment of NASH. In addition, we put these results into new context by summarizing recent studies suggesting these compounds alter mitochondrial metabolism by binding and inhibiting the mitochondrial pyruvate carrier.

Anti-Diabetic Medications for the Pharmacologic Management of NAFLD

As a chronic disease encompassing a wide spectrum of liver-related histologic damage, nonalcoholic fatty liver disease (NAFLD) is becoming a global epidemic with significant impacts on all-cause morbidity and mortality. Insulin resistance and type 2 diabetes mellitus predispose individuals to NAFLD and related complications. Therefore, timely intervention with anti-diabetic medications may prevent and delay the development of NAFLD or have a therapeutic implication. The focus of this review is to evaluate the evidence supporting the efficacy of anti-diabetic medications in the treatment of NAFLD. While many of these anti-diabetic agents have shown to improve biochemical parameters, their effect on hepatic histology is limited. Among anti-diabetic medications, only thiazolidinediones and glucagon-like peptide-1 receptor agonists demonstrate significant improvement in hepatic histology.

Association of non-alcoholic fatty liver disease with cardiovascular disease and subclinical atherosclerosis

Non-alcoholic fatty liver disease (NAFLD) refers to fatty infiltration of liver in the absence of significant alcohol intake, use of steatogenic medication, or hereditary disorders. It is a common cause of chronic liver disease with a worldwide estimated prevalence ranging from 6.3% to 33%. The NAFLD is considered a hepatic manifestation of the metabolic syndrome. Insulin resistance and increased oxidative stress are central to pathogenesis of NAFLD, and risk factors include metabolic syndrome, diabetes mellitus, obesity, lack of physical activity, smoking, and high fat diet. NAFLD is associated with higher mortality as compared to the general population with cardiovascular disease being the most common cause of death. The NAFLD is associated with a higher prevalence of subclinical atherosclerosis as evidenced by odds of higher coronary artery calcification, higher average and maximum carotid intima-media thickness. It is also associated with stiff arteries as evidenced by higher cardio-ankle vascular index and higher brachial-ankle pulse wave velocity. Increasing evidence has linked NAFLD with atherosclerotic cardiovascular diseases. The NAFLD is associated with a higher prevalence of coronary artery disease (CAD), more severe CAD, poor coronary collateral development, and higher incidence of coronary events. The NAFLD is also associated with ischemic stroke. Studies have shown that the association between NAFLD and atherosclerotic cardiovascular diseases is independent of shared risk factors.

Impact of obesity on the toxicity of a multi-ingredient dietary supplement, OxyELITE Pro™ (New Formula), using the novel NZO/HILtJ obese mouse model: Physiological and mechanistic assessments

Herbal dietary supplement (HDS)-induced hepato- and cardiotoxicity is an emerging clinical problem. In this study, we investigated the liver and heart toxicity of HDS OxyELITE-PRO™ New Formula (OEP-NF), a dietary supplement marketed for weight loss and performance enhancement that was recently withdrawn from the market. Using a novel NZO/HlLtJ obese mouse model, we demonstrated that administration of clinically relevant mouse equivalent doses (MED) of OEP-NF produced cardio- and hepatotoxic risks following both short- and long-term administration schedules. Specifically, gavaging female NZO/HlLtJ with up to 2X MED of OEP-NF resulted in 40% mortality within two weeks. Feeding mice with either 1X or 3X MED of OEP-NF for eight weeks, while not exhibiting significant effects on body weights, significantly altered hepatic gene expression, increased the number of apoptotic and mast cells in the heart and affected cardiac function. The degree of toxicity in NZO/HlLtJ mice was higher than that observed previously in non-obese CD-1 and B6C3F1 strains, suggesting that an overweight/obese condition can sensitize mice to OEP-NF. Adverse health effects linked to OEP-NF, together with a number of other hepato- and cardiotoxicity cases associated with HDS ingestion, argue strongly for introduction of quality standards and pre-marketing safety assessments for multi-ingredient HDS.

A systematic review of the present and future of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in the Western world. Ongoing research has furthered our understanding of NAFLD, the nature of progression of this disease, and its impact on morbidity and mortality. An active form of NAFLD is non-alcoholic steatohepatitis (NASH); it is the most severe subtype, without any current recommended therapies, according to the European Medicines Agency. The development of new therapies presents challenges, notably due to the slow progression of NASH and the clinically relevant endpoints.

Correlating new data with effective treatment regimens is an emerging challenge, which will increase our understanding of the factors affecting the NAFLD course. This can enable more appropriate non-invasive prognostic assessments, which can focus on specifically at-risk NAFLD populations for tailored individual treatment. This review article aims to highlight the current developments in the field of NAFLD: pathogenesis, epidemiology, diagnosis, clinical features, and available treatment, including novel targets and therapies.

Future trends in the treatment of non-alcoholic steatohepatitis

With an estimated prevalence of ≈25% in Western and Asian countries, non alcoholic fatty liver disease (NAFLD), caused by chronic excessive caloric intake, is the emerging as the most prevalent liver disorder worldwide. NAFLD exists in two clinical entities, non-alcoholic fatty liver disease (NAFL), a relative benign disease that carry on minimal risk of liver-related morbidity but significant risk of cardiovascular complications, and non-alcoholic steatohepatitis (NASH), a progressive liver disorder with a significant risk for development of liver-related morbidities and mortality. While, liver injury in NASH is contributed by lipid overload in hepatocytes, lipotoxicity, the main determinant of disease progression is an inflammation-driven fibrotic response. Here, we review the landscape of emerging pharmacological interventions in the treatment of NAFL and NASH. A consensus exists that, while treating the liver component of NASH requires development of novel pharmacological approaches, the future therapy of NASH needs to be tailored to the single patient and most likely will be a combination of agents acting on specific pathogenic mechanisms at different disease stage.

Mechanisms of NAFLD development and therapeutic strategies

There has been a rise in the prevalence of nonalcoholic fatty liver disease (NAFLD), paralleling a worldwide increase in diabetes and metabolic syndrome. NAFLD, a continuum of liver abnormalities from nonalcoholic fatty liver (NAFL) to nonalcoholic steatohepatitis (NASH), has a variable course but can lead to cirrhosis and liver cancer. Here we review the pathogenic and clinical features of NAFLD, its major comorbidities, clinical progression and risk of complications and in vitro and animal models of NAFLD enabling refinement of therapeutic targets that can accelerate drug development. We also discuss evolving principles of clinical trial design to evaluate drug efficacy and the emerging targets for drug development that involve either single agents or combination therapies intended to arrest or reverse disease progression.

Current and future therapeutic regimens for nonalcoholic fatty liver disease and nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) and its progressive form non-alcoholic steatohepatitis (NASH), are rapidly becoming among the top causes of cirrhosis, hepatocellular carcinoma, and indications for liver transplantation. Other than lifestyle modification through diet and exercise, there are currently no other approved treatments for NASH/NAFLD. Although weight loss can be effective, it is difficult to achieve and sustain. In contrast, bariatric surgery can improve metabolic conditions associated with NAFLD, and has been shown to improve liver histology. To have approved regimens for the treatment of NASH/NAFLD, several issues must be addressed. First, all stakeholders must agree on the most appropriate clinical trial endpoints for NASH. Currently, resolution of NASH (without worsening fibrosis) or reduction of fibrosis stage (without worsening NASH) are the accepted endpoints by the regulatory authorities. It is important to recognize the prognostic implication of histologic features of NASH. In this context, although histologic NASH has been associated with advanced fibrosis, it is not an independent predictor of long-term mortality. In contrast, there are significant data to suggest that fibrosis stage is the only robust and independent predictor of liver-related mortality. In addition to the primary endpoints, several important secondary endpoints, including noninvasive biomarkers, long-term outcomes, and patient-reported outcomes must be considered. In 2018, a few phase 3 clinical trials for the treatment of NASH have been initiated. Additionally, a number of phase 2a and 2b clinical trials targeting different pathogenic pathways in NASH are in the pipeline of emerging therapies.

CONCLUSION

Over the next 5 years, some of these regimens are expected to provide potential new treatment options for patients with NASH/NAFLD. (Hepatology 2018;68:361-371).

Non-alcoholic Fatty Liver Disease: A Review of Anti-diabetic Pharmacologic Therapies

Non-alcoholic fatty liver disease (NAFLD), the most common cause of liver disease, affects approximately 75 to 100 million Americans. Patients with concurrent NAFLD and type 2 diabetes mellitus have a higher risk of progressing to advanced fibrosis and non-alcoholic steatohepatitis compared to non-diabetics. Lifestyle modifications, including weight loss, remain the mainstay of treatment for NAFLD, as there are no medications currently indicated for this disease state. Anti-diabetic pharmacologic therapies aimed at improving insulin sensitivity and decreasing insulin production have been studied to determine their potential role in slowing the progression of NAFLD. In this review, we focus on the evidence surrounding anti-diabetic medications and their ability to improve disease progression in patients with NAFLD.

Dual PPARα/γ agonist saroglitazar improves liver histopathology and biochemistry in experimental NASH models

BACKGROUND & AIMS

Non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) are common clinico-pathological conditions that affect millions of patients worldwide. In this study, the efficacy of saroglitazar, a novel PPARα/γ agonist, was assessed in models of NAFLD/NASH.

METHODS & RESULTS

HepG2 cells treated with palmitic acid (PA;0.75 mM) showed decreased expression of various antioxidant biomarkers (SOD1, SOD2, glutathione peroxidase and catalase) and increased expression of inflammatory markers (TNFα, IL1β and IL6). These effects were blocked by saroglitazar, pioglitazone and fenofibrate (all tested at 10μM concentration). Furthermore, these agents reversed PA-mediated changes in mitochondrial dysfunction, ATP production, NFkB phosphorylation and stellate cell activation in HepG2 and HepG2-LX2 Coculture studies. In mice with choline-deficient high-fat diet-induced NASH, saroglitazar reduced hepatic steatosis, inflammation, ballooning and prevented development of fibrosis. It also reduced serum alanine aminotransferase, aspartate aminotransferase and expression of inflammatory and fibrosis biomarkers. In this model, the reduction in the overall NAFLD activity score by saroglitazar (3 mg/kg) was significantly more prominent than pioglitazone (25 mg/kg) and fenofibrate (100 mg/kg). Pioglitazone and fenofibrate did not show any improvement in steatosis, but partially improved inflammation and liver function. Antifibrotic effect of saroglitazar (4 mg/kg) was also observed in carbon tetrachloride-induced fibrosis model.

CONCLUSIONS

Saroglitazar, a dual PPARα/γ agonist with predominant PPARα activity, shows an overall improvement in NASH. The effects of saroglitazar appear better than pure PPARα agonist, fenofibrate and PPARγ agonist pioglitazone.

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.

NAFLD/NASH in patients with type 2 diabetes and related treatment options

Type 2 diabetes may reduce life expectancy and patients' quality of life due to its micro- and macro-vascular complications and to the higher risk of several types of cancer. An emerging important factor is represented by the hepatic involvement; it is recognized that excessive hepatic fat accumulation represents a typical feature of diabetic patients and that it also plays an important pathogenic role. It is now evident that non-alcoholic fatty liver disease (NAFLD), generally perceived as a benign condition, may have on the contrary an important deleterious impact for diabetic patients increasing the risk to develop cardiovascular complications but also serious hepatic diseases, in particular non-alcoholic steatohepatitis (NASH), cirrhosis and hepatocellular carcinoma. Lifestyle intervention, bariatric surgery and several drug therapies have now accumulated evidence of efficacy in treating NASH. On the other hand, their durability and safety in the long-term is yet to be proven and their use may be sometimes associated with side effects or higher risk of adverse events limiting the regular administration or contraindicating it. Professional health care providers, building awareness about the importance of these hepatic complications, should put more efforts in primary prevention using a behavioral therapy needing a multidisciplinary approach, in secondary prevention applying on a regular basis in the clinical setting available predictive algorithms to identify the patients at higher cardiovascular and hepatologic risk, and in tertiary prevention treating, when not contraindicated, the diabetic patients preferentially with drugs with proven benefit on NAFLD/NASH.

Omega-3 fatty acids and non-alcoholic fatty liver disease: Evidence of efficacy and mechanism of action

For many years it has been known that high doses of long chain omega-3 fatty acids are beneficial in the treatment of hypertriglyceridaemia. Over the last three decades, there has also been a wealth of in vitro and in vivo data that has accumulated to suggest that long chain omega-3 fatty acid treatment might be beneficial to decrease liver triacylglycerol. Several biological mechanisms have been identified that support this hypothesis; notably, it has been shown that long chain omega-3 fatty acids have a beneficial effect: a) on bioactive metabolites involved in inflammatory pathways, and b) on alteration of nuclear transcription factor activities such as peroxisome proliferator-activated receptors (PPARs), sterol regulatory element-binding protein 1c (SREBP-1c) and carbohydrate-responsive element-binding protein (ChREBP), involved in inflammatory pathways and liver lipid metabolism. Since the pathogenesis of non alcoholic fatty liver disease (NAFLD) begins with the accumulation of liver lipid and progresses with inflammation and then several years later with development of fibrosis; it has been thought in patients with NAFLD omega-3 fatty acid treatment would be beneficial in treating liver lipid and possibly also in ameliorating inflammation. Meta-analyses (of predominantly dietary studies and small trials) have tended to support the assertion that omega-3 fatty acids are beneficial in decreasing liver lipid, but recent randomised controlled trials have produced conflicting data. These trials have suggested that omega-3 fatty acid might be beneficial in decreasing liver triglyceride (docosahexanoic acid also possibly being more effective than eicosapentanoic acid) but not in decreasing other features of steatohepatitis (or liver fibrosis). The purpose of this review is to discuss recent evidence regarding biological mechanisms by which long chain omega-3 fatty acids might act to ameliorate liver disease in NAFLD; to consider the recent evidence from randomised trials in both adults and children with NAFLD; and finally to discuss key 'known unknowns' that need to be considered, before planning future studies that are focussed on testing the effects of omega-3 fatty acid treatment in patients with NAFLD.

Nonalcoholic fatty liver disease and chronic vascular complications of diabetes mellitus

Nonalcoholic fatty liver disease (NAFLD) and diabetes mellitus are common diseases that often coexist and might act synergistically to increase the risk of hepatic and extra-hepatic clinical outcomes. NAFLD affects up to 70-80% of patients with type 2 diabetes mellitus and up to 30-40% of adults with type 1 diabetes mellitus. The coexistence of NAFLD and diabetes mellitus increases the risk of developing not only the more severe forms of NAFLD but also chronic vascular complications of diabetes mellitus. Indeed, substantial evidence links NAFLD with an increased risk of developing cardiovascular disease and other cardiac and arrhythmic complications in patients with type 1 diabetes mellitus or type 2 diabetes mellitus. NAFLD is also associated with an increased risk of developing microvascular diabetic complications, especially chronic kidney disease. This Review focuses on the strong association between NAFLD and the risk of chronic vascular complications in patients with type 1 diabetes mellitus or type 2 diabetes mellitus, thereby promoting an increased awareness of the extra-hepatic implications of this increasingly prevalent and burdensome liver disease. We also discuss the putative underlying mechanisms by which NAFLD contributes to vascular diseases, as well as the emerging role of changes in the gut microbiota (dysbiosis) in the pathogenesis of NAFLD and associated vascular diseases.

A critical review of endpoints for non-cirrhotic NASH therapeutic trials

Non-alcoholic steatohepatitis is a disease without a single, specific, diagnostic marker, hence multiple indicators are required to measure therapeutic efficacy. Moreover, drug candidates for non-alcoholic steatohepatitis target many distinct mechanisms that are believed to promote hepatic injury. Therefore, a wide range of endpoints must be reached, sequentially, as required by the drug development process. Some of these endpoints validate the mechanism of action, others are used to anticipate histological efficacy. Histological endpoints are still considered the best predictors of clinical outcome, but they can only be reliably tested in larger, late phase trials. Herein, we will review the rationale and clinical data supporting the use of specific endpoints at different stages of therapeutic trials. We will also discuss the validity and limitations of current phase IIb histological endpoints, particularly a one stage reduction in fibrosis, for their ability to predict progression to cirrhosis, which is the ultimate outcome measure in therapeutic trials.

Current Treatment of Nonalcoholic Fatty Liver Disease/Nonalcoholic Steatohepatitis

Treatment of nonalcoholic fatty liver disease (NAFLD)/nonalcoholic steatohepatitis (NASH) is focused on patients with NASH because they are at highest risk for progressive liver disease. Current first-line treatment consists of lifestyle modifications. Patients should lose at least 7% to 10% of body weight via a combination of physical exercise and calorie restriction dieting. Surgical or endoscopic surgery for weight loss can be considered in obese patients, depending on degree of excess body weight and comorbidities. There is no currently approved pharmacotherapy for NASH. Vitamin E and pioglitazone have the most evidence of therapeutic efficacy but have limitations. The treatment modality chosen should be individualized.

Altered pharmacokinetics of rosiglitazone in a mouse model of non-alcoholic fatty liver disease

BACKGROUND

Severe forms of non-alcoholic fatty liver disease (NAFLD) adversely affect the liver physiology and hence the pharmacokinetics of drugs. Here, we investigated the effect of NAFLD on the pharmacokinetics of rosiglitazone, an insulin sensitizer used in the treatment of type 2 diabetes.

METHODS

Male C57BL/6 mice were divided into two groups. The first group (n=14) was fed with normal chow feed and the second group (n=14) was fed with 60% high-fat diet (HFD) and 40% high fructose liquid (HFL) for 60 days to induce NAFLD. The development of NAFLD was confirmed by histopathology, liver triglyceride levels and biochemical estimations, and used for pharmacokinetic investigations. Rosiglitazone was administered orally at 30 mg/kg dose. At predetermined time points, blood was collected and rosiglitazone concentrations were determined using LC/MS/MS. Plasma concentrations were subjected to non-compartmental analysis using Phoenix WinNonlin (6.3), and the area under the plasma concentration-time curve (AUC) was calculated by the linear-up log-down method.

RESULTS

HFD and HFL diet successfully induced NAFLD in mice. Rosiglitazone pharmacokinetics in NAFLD animals were altered significantly as compared to healthy mice. Rosiglitazone exposure increased significantly in NAFLD mice (2.5-fold higher AUC than healthy mice). The rosiglitazone oral clearance was significantly lower and the mean plasma half-life was significantly longer in NAFLD mice as compared to healthy mice.

CONCLUSIONS

The NAFLD mouse model showed profound effects on rosiglitazone pharmacokinetics. The magnitude of change in rosiglitazone pharmacokinetics is similar to that observed in humans with moderate to severe liver disease. The present animal model can be utilized to study the NAFLD-induced changes in the pharmacokinetics of different drugs.

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.

Potential role of thymosin beta 4 in the treatment of nonalcoholic fatty liver disease

As a result of increased prevalence of obesity worldwide, non-alcoholic fatty liver disease (NAFLD) has become one of the most common causes of chronic liver disease. Although most NAFLD cases remain benign, some progress to end-stage liver diseases such as cirrhosis and hepatocellular carcinoma. Therefore, treatment should be considered for NAFLD patients who are likely to progress to nonalcoholic steatohepatitis (NASH) or fibrosis. Thymosin beta 4 (Tβ4), a G-actin sequestering peptide, regulates actin polymerization in mammalian cells. In addition, studies have reported anti-inflammatory, insulin-sensitizing, and anti-fibrotic effects of Tβ4. However, no research has been done to investigate the effects of Tβ4 on NAFLD. Based on the findings above mentioned, we hypothesize that Tβ4 may represent an effective treatment for NAFLD.

Pioglitazone Enhances Cytosolic Lipolysis, β-oxidation and Autophagy to Ameliorate Hepatic Steatosis

Non-alcoholic fatty liver disease closely contributes to the development of obesity and insulin resistance. Even though pioglitazone has been reported to effectively lessen hepatic steatosis in human studies, its molecular mechanism remains unclear. This study is designed to investigate the regulation of cytosolic lipolysis, β-oxidation and autophagy by pioglitazone in a mice model of high fat diet (HFD) and cell model incubated with palmitic acid. Our results revealed hepatic steatosis was apparently induced by HFD and it was significantly reversed by pioglitazone. The serum insulin and hepatic triglyceride content was significantly decreased by co-administered pioglitazone with HFD. Hepatic expression of cytosolic-lipolysis related proteins (ATGL, HSL), β-oxidation (CPT-1A) and autophagy-related proteins (ATG7, LC3, LAL) was significantly enhanced by pioglitazone. Knockdown PPARα/PPARγ in AML12 cells significantly and proportionally reduced the expressions of ATGL, CPT-1A and LC3II, which was induced by pioglitazone. Furthermore, facilitation of the autophagic flux by pioglitazone was obviously blocked by lysosomal inhibitor, leupeptin, to demonstrate accumulation of the LC3II and intracellular lipid in AML12 cells. Our results demonstrated that pioglitazone attenuating the hepatic steatosis may be mediated by enhancing cytosolic lipolysis, β-oxidation and autophagy in a PPARα and PPARγ dependent manner.

Current management of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is characterized by hepatic accumulation of lipid in patients who do not consume alcohol in amounts generally considered harmful to the liver. NAFLD is becoming a major liver disease in Eastern countries and it is related to insulin resistance and metabolic syndrome. Treatment has focused on improving insulin sensitivity, protecting the liver from oxidative stress, decreasing obesity and improving diabetes mellitus, dyslipidemia, hepatic inflammation and fibrosis. Lifestyle modification involving diet and enhanced physical activity associated with the treatment of underlying metabolic are the main stain in the current management of NAFLD. Insulin-sensitizing agents and antioxidants, especially thiazolidinediones and vitamin E, seem to be the most promising pharmacologic treatment for non-alcoholic steatohepatitis, but further long-term multicenter studies to assess safety are recommended.

Inflammation is independent of steatosis in a murine model of steatohepatitis

Obesity and alcohol consumption synergistically promote steatohepatitis, and neutrophil infiltration is believed to be associated with steatosis. However, the underlying mechanisms remain obscure. Peroxisome proliferator-activated receptor gamma (PPARγ) plays a complex role in lipid metabolism and inflammation; therefore, the purpose of this study was to dissect its role in regulating steatosis and neutrophil infiltration in a clinically relevant mouse steatohepatitis model of 3-month high-fat diet (HFD) feeding plus a binge of ethanol (HFD-plus-binge ethanol). Hepatocyte-specific Pparg disruption reduced liver steatosis but surprisingly increased hepatic neutrophil infiltration after HFD-plus-binge ethanol. Knockout or knockdown of the PPARγ target gene, fat-specific protein 27, reduced steatosis without affecting neutrophil infiltration in this model. Moreover, hepatocyte-specific deletion of the Pparg gene, but not the fat-specific protein 27 gene, markedly up-regulated hepatic levels of the gene for chemokine (C-X-C motif) ligand 1 (Cxcl1, a chemokine for neutrophil infiltration) in HFD-plus-binge ethanol-fed mice. In vitro, deletion of the Pparg gene also highly augmented palmitic acid or tumor necrosis factor alpha induction of Cxcl1 in mouse hepatocytes. In contrast, activation of PPARγ with a PPARγ agonist attenuated Cxcl1 expression in hepatocytes. Palmitic acid also up-regulated interleukin-8 (a key chemokine for human neutrophil recruitment) expression in human hepatocytes, which was attenuated and enhanced by cotreatment with a PPARγ agonist and antagonist, respectively. Finally, acute ethanol binge markedly attenuated HFD-induced hepatic PPARγ activation, which contributed to the up-regulation of hepatic Cxcl1 expression post-HFD-plus-binge ethanol.

CONCLUSION

Hepatic PPARγ plays an opposing role in controlling steatosis and neutrophil infiltration, leading to dissociation between steatosis and inflammation; acute ethanol gavage attenuates hepatic PPARγ activation and subsequently up-regulates hepatic CXCL1/interleukin-8 expression, thereby exacerbating hepatic neutrophil infiltration. (Hepatology 2017;66:108-123).

Does Weight Gain Associated with Thiazolidinedione Use Negatively Affect Cardiometabolic Health?

Thiazolidinediones (TZDs) are oral anti-diabetic drugs that are peroxisome proliferator-activated receptor gamma (PPARγ) agonists and act as insulin sensitizers. The clinical efficacy and durability of the currently available TZDs in improving glycemic control are well established. However, TZDs cause weight gain, which has been thought to be a class effect of TZDs. TZD-associated weight gain may result mainly from increased fat mass and fluid retention and may be in part congruent to the mechanism of action of TZD. Increases in fat mass are almost exclusively limited to subcutaneous fat, while there are no effects or even decreases in visceral fat. Insulin resistance and cardiovascular risk associated with fat accumulation (obesity) depend on body fat distribution, with visceral fat associated with insulin resistance and a greater degree of risk than subcutaneous fat. Therefore, despite TZD-associated weight gain, TZDs are less likely to confer an increased risk of insulin resistance and cardiovascular complications. As patients with diabetes are younger and/or more obese in Korea, TZDs may be a cost-effective treatment option, offering a unique insulin-sensitizing action and good durability for the long-term management of type 2 diabetes.

Efficacy and safety of glucagon-like peptide-1 receptor agonists in non-alcoholic fatty liver disease: A systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

New drugs are urgently needed for the treatment of non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH). The aim of this meta-analysis was to evaluate the efficacy and safety of glucagon-like peptide-1 receptor agonists (GLP-1RAs) in NAFLD/NASH.

METHODS

We searched the MEDLINE, Embase, and Cochrane Library Central to identify randomized controlled trials (RCTs) and observational studies that compared GLP-1RAs with a control treatment or baseline values with respect to efficacy and safety in patients with NAFLD/NASH. Mean differences (MDs) with 95% confidence intervals (CIs) and odds ratios (ORs) were pooled using a random-effect model.

RESULTS

Six studies were eligible and included. Among the 329 NAFLD/NASH patients included in these studies, 277 patients had type 2 diabetes (T2D). GLP-1RA treatment produced significant reductions relative to baseline in liver histology scores for steatosis (MD, 0.80; 95% CI, 0.49 to 1.11), lobular inflammation (MD, 0.22; 95% CI, 0.00 to 0.45), hepatocellular ballooning (MD, 0.41; 95% CI, 0.15 to 0.67) and fibrosis (MD, 0.35; 95% CI, 0.00 to 0.70). Compared with placebo and positive agents, GLP-1RAs significantly reduced gamma-glutamyl transpeptidase (GGT) levels (MD, 13.8 U/L; 95% CI, 7.4 to 20.3; P<0.001). The reported major adverse events associated with GLP-1RA treatment included mild to moderate gastrointestinal discomfort that resolved within a few weeks.

CONCLUSIONS

Our study suggests that in NASH patients, particularly patients with diabetes, GLP-1RAs may improve liver histology and reduce aminotransferase levels from baseline. Benefits of GLP-1RAs are considered to outweigh the risks in NAFLD/NASH patients with or without diabetes.

Supplementation with Vitis vinifera L. skin extract improves insulin resistance and prevents hepatic lipid accumulation and steatosis in high-fat diet-fed mice

Nonalcoholic fatty liver disease is one of the most common complications of obesity. The Vitis vinifera L. grape skin extract (ACH09) is an important source of polyphenols, which are related to its antioxidant and antihyperglycemic activities. We hypothesized that ACH09 could also exert beneficial effects on metabolic disorders associated with obesity and evaluated ACH09's influence on high-fat (HF) diet-induced hepatic steatosis and insulin resistance in C57BL/6 mice. The animals were fed a standard diet (10% fat, control) or an HF diet (60% fat, HF) with or without ACH09 (200mg/[kg d]) for 12weeks. Our results showed that ACH09 reduced HF diet-induced body weight gain, prevented hepatic lipid accumulation and steatosis, and improved hyperglycemia and insulin resistance. The underlying mechanisms of these beneficial effects of ACH09 may involve the activation of hepatic insulin-signaling pathway because the expression of phosphorylated insulin receptor substrate-1, phosphatidylinositol 3-kinase, phosphorylated Akt serine/threonine kinase 1, and glucose transporter 2 was increased by ACH09 and correlated with improvement of hyperglycemia, hyperinsulinemia, and insulin resistance. ACH09 reduced the expression of the lipogenic factor sterol regulatory-element binding protein-1c in the liver and upregulated the lipolytic pathway (phosphorylated liver kinase B1/phosphorylated adenosine-monophosphate-activated protein kinase), which was associated with normal hepatic levels of triglyceride and cholesterol and prevention of steatosis. ACH09 prevented the hepatic oxidative damage in HF diet-fed mice probably by restoration of antioxidant activity. In conclusion, ACH09 protected mice from HF diet-induced obesity, insulin resistance, and hepatic steatosis. The regulation of hepatic insulin signaling pathway, lipogenesis, and oxidative stress may contribute to ACH09's protective effect.

NASH Therapy: omega 3 supplementation, vitamin E, insulin sensitizers and statin drugs

Non-alcoholic steatohepatitis (NASH) is the more aggressive form of non-alcoholic fatty liver disease (NAFLD). NASH can progress to hepatic fibrosis, cirrhosis, portal hypertension and primary liver cancer. Therapy is evolving with a substantial number of trials of promising new agents now in progress. In this article however, we will examine data for several older forms of therapy which have been fairly extensively studied over the years: Polyunsaturated Fatty Acid (PUFA) supplements, vitamin E, insulin sensitizing agents with a focus on pioglitazone and statin agents. Early interest in PUFA derived from their potential benefit in cardio-metabolic disease and the close association of NAFLD/NASH with Metabolic Syndrome. Results have been variable although most studies show reduction of liver fat without other major effects and their effects are influenced by concomitant weight loss and underlying genetic factors. Vitamin E has had some efficacy in pediatric NASH but questionable efficacy in even mild NASH among adults. Pioglitazone has shown significant histological benefit in a number of trials but concern over side-effects (especially weight gain) have dampened enthusiasm. A newer insulin sensitizer, liraglutide, has also shown promise in a small randomized, controlled trial. Very limited data exists regarding the histological effects of the statins in NASH and these agents appear to be fairly neutral with neither clear cut benefit nor detriment. Their use is best guided by cardiovascular risks rather than liver histology.

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.

Thiazolidinediones and Advanced Liver Fibrosis in Nonalcoholic Steatohepatitis: A Meta-analysis

IMPORTANCE

Nonalcoholic steatohepatitis (NASH) is projected to be the leading cause of liver transplantation by 2020. Advanced fibrosis (stage F3-F4) on liver biopsy independently predicts all-cause and liver-related mortality in NASH. There are no known efficacious treatments for advanced fibrosis related to NASH. Thiazolidinedione therapy has been extensively evaluated in NASH, and new randomized clinical trials (RCTs) of its efficacy have been completed.

OBJECTIVE

To synthesize the evidence about the association of thiazolidinedione therapy with advanced liver fibrosis in NASH.

DATA SOURCES

MEDLINE, Ovid MEDLINE In-Process, Cochrane Library, EMBASE, clinicaltrials.gov, PubMed, and Scopus databases (without language restrictions), as well as other registries and scientific meeting presentations, from database inception through August 15, 2016.

STUDY SELECTION

Randomized clinical trials evaluating the effect of thiazolidinedione therapy on histologic features of the liver in biopsy-proven NASH.

DATA EXTRACTION AND SYNTHESIS

Two investigators extracted study data independently and in duplicate and rated the risk of bias using the Cochrane Risk of Bias Tool.

MAIN OUTCOMES AND MEASURES

The primary outcome was a dichotomous improvement in advanced fibrosis on liver biopsy, defined as an improvement in fibrosis stage from F3-F4 to F0-F2. Secondary outcomes were at least a 1-point improvement in fibrosis of any stage and NASH resolution. This meta-analysis also evaluated adverse effects of thiazolidinedione therapy, including weight gain, lower limb edema, congestive heart failure, bone fractures, cancer, and anemia. With the use of random-effects models, dichotomous variables are presented as odds ratios (ORs) with 95% CIs, and continuous variables are presented as weighted mean differences with 95% CIs.

RESULTS

This study analyzed 8 RCTs (5 evaluating pioglitazone use and 3 evaluating rosiglitazone maleate use) enrolling 516 patients with biopsy-proven NASH for a duration of 6 to 24 months. Among all studies combined, thiazolidinedione therapy was associated with improved advanced fibrosis (OR, 3.15; 95% CI, 1.25-7.93; P = .01; I2 = 0%), fibrosis of any stage (OR, 1.66; 95% CI, 1.12-2.47; P = .01; I2 = 0%), and NASH resolution (OR, 3.22; 95% CI, 2.17-4.79; P < .001; I2 = 0%). Analyses restricted to RCTs enrolling patients without diabetes yielded similar results for improvement in advanced fibrosis (OR, 2.95; 95% CI, 1.04-10.90; P = .02; I2 = 0%), improvement in fibrosis of any stage (OR, 1.76; 95% CI, 1.02-3.03; P = .02; I2 = 0%), and NASH resolution (OR, 3.40; 95% CI, 1.95-5.93; P < .001; I2 = 0%). All effects were accounted for by pioglitazone use. Weight gain and lower limb edema occurred more frequently with thiazolidinedione therapy (initial body weight +2.70%; 95% CI, 1.96%-4.34%; P = .001). The small sample size of included RCTs prevented evaluation of more serious adverse effects of thiazolidinedione therapy.

CONCLUSIONS AND RELEVANCE

Pioglitazone use improves advanced fibrosis in NASH, even in patients without diabetes. Whether this finding translates to improvement in risk for clinical outcomes requires further study.

Treating fatty liver disease by modulating mitochondrial pyruvate metabolism

Modifying the entry of pyruvate into mitochondria may provide a unique approach to treat metabolic disease. The pharmacology of a new class of insulin sensitizers directed against a newly identified mitochondrial target may treat many aspects of nonalcoholic steatohepatitis, including fibrosis. This commentary suggests treating nonalcoholic steatohepatitis through a newly identified mechanism consistent with pathophysiology. (Hepatology Communications 2017;1:193‐197)

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.

Mitochondrial Adaptation in Nonalcoholic Fatty Liver Disease: Novel Mechanisms and Treatment Strategies

Nonalcoholic fatty liver disease (NAFLD) is prevalent in patients with obesity or type 2 diabetes. Nonalcoholic steatohepatitis (NASH), encompassing steatosis with inflammation, hepatocyte injury, and fibrosis, predisposes to cirrhosis, hepatocellular carcinoma, and even cardiovascular disease. In rodent models and humans with NAFLD/NASH, maladaptation of mitochondrial oxidative flux is a central feature of simple steatosis to NASH transition. Induction of hepatic tricarboxylic acid cycle closely mirrors the severity of oxidative stress and inflammation in NASH. Reactive oxygen species generation and inflammation are driven by upregulated, but inefficient oxidative flux and accumulating lipotoxic intermediates. Successful therapies for NASH (weight loss alone or with incretin therapy, or pioglitazone) likely attenuate mitochondrial oxidative flux and halt hepatocellular injury. Agents targeting mitochondrial dysfunction may provide a novel treatment strategy for NAFLD.

Effect of modulation of PPAR-γ activity on Kupffer cells M1/M2 polarization in the development of non-alcoholic fatty liver disease

Abnormal lipid-mediated hepatic inflammatory-immune dysfunction and chronic low grade inflammation play an important role in the pathogenesis of non-alcoholic fatty liver disease (NAFLD). Macrophage polarization is an important mechanism for the regulation of inflammatory response. Since PPAR-γ has emerged as a master regulator of macrophage polarization, we aimed to investigate the lipid-induced macrophage/Kupffer cell polarization in vivo and in vitro, and explore the association between PPAR-γ activity and macrophages M1/M2 polarization shifting. Here we showed that long-term high-fat diet increased Kupffer cells content with M1-predominant phenotype and increasing production of pro-inflammatory cytokines. Saturated fatty acids polarized Kupffer cells/macrophages to an M1-predominant phenotype while n-3 PUFA polarized Kupffer cells/macrophages to an M2 phenotype, which was associated with activation of NF-κB signal pathway and PPAR-γ respectively. Furthermore, up-regulation of PPAR-γ shifted lipid-induced macrophages polarization from M1-predominant phenotype to M2 phenotype. Macrophages polarization switch was associated with the interaction between PPAR-γ and NF-κBp65 signal pathway. Rosiglitazone restored high-fat diet-induced imblance of Kupffer cells M1/M2 polarization and alleviated hepatic steatosis as well as local pro-inflammatory response. These findings suggest that manipulation of PPAR-γ activity has the potential to balance lipid-induced M1/M2 macrophage/Kupffer cell polarization, and leading to prevent the development of NAFLD.

Reversal of liver cirrhosis: current evidence and expectations

In the past, liver cirrhosis was considered an irreversible phenomenon. However, many experimental data have provided evidence of the reversibility of liver fibrosis. Moreover, multiple clinical studies have also shown regression of fibrosis and reversal of cirrhosis on repeated biopsy samples. As various etiologies are associated with liver fibrosis via integrated signaling pathways, a comprehensive understanding of the pathobiology of hepatic fibrogenesis is critical for improving clinical outcomes. Hepatic stellate cells play a central role in hepatic fibrogenesis upon their activation from a quiescent state. Collagen and other extracellular material components from activated hepatic stellate cells are deposited on, and damage, the liver parenchyma and vascular structures. Hence, inactivation of hepatic stellate cells can lead to enhancement of fibrolytic activity and could be a potential target of antifibrotic therapy. In this regard, continued efforts have been made to develop better treatments for underlying liver diseases and antifibrotic agents in multiple clinical and therapeutic trials; the best results may be expected with the integration of such evidence. In this article, we present the underlying mechanisms of fibrosis, current experimental and clinical evidence of the reversibility of liver fibrosis/cirrhosis, and new agents with therapeutic potential for liver fibrosis.

Role of nonalcoholic fatty liver disease as risk factor for drug-induced hepatotoxicity

BACKGROUND

Obesity is often associated with nonalcoholic fatty liver disease (NAFLD), which refers to a large spectrum of hepatic lesions including fatty liver, nonalcoholic steatohepatitis (NASH) and cirrhosis. Different investigations showed or suggested that obesity and NAFLD are able to increase the risk of hepatotoxicity of different drugs. Some of these drugs could induce more frequently an acute hepatitis in obese individuals whereas others could worsen pre-existing NAFLD.

AIM

The main objective of the present review was to collect the available information regarding the role of NAFLD as risk factor for drug-induced hepatotoxicity. For this purpose, we performed a data-mining analysis using different queries including drug-induced liver injury (or DILI), drug-induced hepatotoxicity, fatty liver, nonalcoholic fatty liver disease (or NAFLD), steatosis and obesity. The main data from the collected articles are reported in this review and when available, some pathophysiological hypotheses are put forward.

RELEVANCE FOR PATIENTS

Drugs that could pose a potential risk in obese patients include compounds belonging to different pharmacological classes such as acetaminophen, halothane, methotrexate, rosiglitazone, stavudine and tamoxifen. For some of these drugs, experimental investigations in obese rodents confirmed the clinical observations and unveiled different pathophysiological mechanisms which could explain why these pharmaceuticals are particularly hepatotoxic in obesity and NAFLD. Other drugs such as pentoxifylline, phenobarbital and omeprazole might also pose a risk but more investigations are required to determine whether this risk is significant or not. Because obese people often take several drugs for the treatment of different obesity-related diseases such as type 2 diabetes, hyperlipidemia and coronary heart disease, it is urgent to identify the main pharmaceuticals that can cause acute hepatitis on a fatty liver background or induce NAFLD worsening.