Efficacy of insulin-sensitizing agents in nonalcoholic fatty liver disease

Current type 2 diabetes guidelines: Individualized treatment and how to make the most of metformin

Evidence-based guidelines provide the premise for the delivery of quality care to preserve health and prevent disabilities and premature death. The systematic gathering of observational, mechanistic and experimental data contributes to the hierarchy of evidence used to guide clinical practice. In the field of diabetes, metformin was discovered more than 100 years ago, and with 60 years of clinical use, it has stood the test of time regarding its value in the prevention and management of type 2 diabetes. Although some guidelines have challenged the role of metformin as the first-line glucose-lowering drug, it is important to point out that the cardiovascular-renal protective effects of sodium-glucose co-transporter-2 inhibitors and glucagon-like peptide-1 receptor agonists were gathered from patients with type 2 diabetes, the majority of whom were treated with metformin. Most national, regional and international guidelines recommend metformin as a foundation therapy with emphasis on avoidance of therapeutic inertia and early attainment of multiple treatment goals. Moreover, real-world evidence has confirmed the glucose-lowering and cardiovascular-renal benefits of metformin accompanied by an extremely low risk of lactic acidosis. In patients with type 2 diabetes and advanced chronic kidney disease (estimated glomerular filtration rate 15-30 mL/min/1.73m2), metformin discontinuation was associated with an increased risk of cardiovascular-renal events compared with metformin persistence. Meanwhile, it is understood that microbiota, nutrients and metformin can interact through the gut-brain-kidney axis to modulate homeostasis of bioactive molecules, systemic inflammation and energy metabolism. While these biological changes contribute to the multisystem effects of metformin, they may also explain the gastrointestinal side effects and vitamin B12 deficiency associated with metformin intolerance. By understanding the interactions between metformin, foods and microbiota, healthcare professionals are in a better position to optimize the use of metformin and mitigate potential side effects. The United Kingdom Prospective Diabetes Study and the Da Qing Diabetes Prevention Program commenced 40 years ago provided the first evidence that type 2 diabetes is preventable and treatable. To drive real-world impact from this evidence, payors, practitioners and planners need to co-design and implement an integrated, data-driven, metformin-based programme to detect people with undiagnosed diabetes and prediabetes (intermediate hyperglycaemia), notably impaired glucose tolerance, for early intervention. The systematic data collection will create real-world evidence to bring out the best of metformin and make healthcare sustainable, affordable and accessible.

Optimized strategy among diet, exercise, and pharmacological interventions for nonalcoholic fatty liver disease: A network meta-analysis of randomized controlled trials

BACKGROUND

Emerging treatment methods, including exercise, diet, and drugs, for nonalcoholic fatty liver disease have been proposed. However, the differences in their efficacy have not been determined. We aimed to compare the effects of these treatments excluding surgery via a systematic review and network meta-analysis of randomized controlled trials.

DATA SOURCE

The data sources included PubMed, Embase, Web of Science and Cochrane up to February 1st, 2023. The endpoints consisted of body mass index (BMI), serum markers of metabolism and liver injury markers, liver fat content, and stiffness.

RESULTS

A total of 174 studies with 10,183 patients were included in this meta-analysis. In terms of improving BMI, Pan-agonist of peroxisome proliferator-activated receptors (PPAR) is the best treatment with the highest SUCRA (surface under the cumulative ranking) of 84.8% (mean = -3.40, 95% CI -5.55, -1.24) by the comparative effectiveness ranking. GLP-1 (glucagon-like peptide-1) has the best effect in improving the liver fat content based on the MRI-PDFF, steatosis score (SUCRA 99.7%, mean = -2.19, 95% CI -2.90, -1.48) and ballooning score (SUCRA 61.2%, mean = -0.82, 95% CI -4.46, 2.83).

CONCLUSIONS

Pan-agonist of PPAR was the most efficacious regimen in lowering BMIs, whereas GLP-1R agonists achieved the highest efficacy of steatosis improvement in this network meta-analysis.

Effectiveness of metformin for the reversal of cold-ischemia-induced damage in hepatosteatosis

BACKGROUND

Primary dysfunction and rejection are more common in donor liver tissues with steatosis. AMP-activated protein kinase (AMPK) assumes organ-protective functions during ischemia. Metformin was used for the activation of AMPK in hepatocytes. The aim of this study is to investigate the effectiveness of metformin administration for the reversal of cold-ischemia-induced damage in hepatosteatosis.

MATERIAL AND METHODS

Seven-week-old C7BL56 male-mice (n = 109) were separated into four groups depending on diet type and metformin use. A specific diet model was followed for 10 weeks to induce hepatosteatosis. A group of the animals was administered with metformin for the last four weeks via oral gavage. After resection, the liver tissues were perfused and kept for 0-6-12-24 h in the UW solution. Histopathological examinations were performed, and Western blot was utilized to analyze p-AMPK and AMPK expression levels.

RESULTS

Hepatosteatosis decreased significantly with metformin. The steatotic liver group had more prominent pericentral inflammation, necrosis as well as showing a decreased and more delayed AMPK response than the non-fat group. All these alterations could be corrected using metformin.

CONCLUSION

Metformin can increase the resistance of livers with hepatosteatosis to cold-ischemia-induced damage, which in turn may pave the way for successful transplantation of fatty living-donor livers.

Metformin and the Liver: Unlocking the Full Therapeutic Potential

Metformin is a highly effective medication for managing type 2 diabetes mellitus. Recent studies have shown that it has significant therapeutic benefits in various organ systems, particularly the liver. Although the effects of metformin on metabolic dysfunction-associated steatotic liver disease and metabolic dysfunction-associated steatohepatitis are still being debated, it has positive effects on cirrhosis and anti-tumoral properties, which can help prevent the development of hepatocellular carcinoma. Furthermore, it has been proven to improve insulin resistance and dyslipidaemia, commonly associated with liver diseases. While more studies are needed to fully determine the safety and effectiveness of metformin use in liver diseases, the results are highly promising. Indeed, metformin has a terrific potential for extending its full therapeutic properties beyond its traditional use in managing diabetes.

Comparative efficacy of diabetes medications on liver enzymes and fat fraction in patients with nonalcoholic fatty liver disease: A network meta-analysis,

OBJECTIVES

This network meta-analysis (NMA) aimed to evaluate the relative rank-order of existing diabetes medications in patients with nonalcoholic fatty liver disease (NAFLD) with or without type 2 diabetes mellitus (T2DM).

METHODS

A systematic literature search was conducted using the Medline, Embase and Cochrane databases. Clinical trials comparing the efficacy of diabetes medications with other interventions, including lifestyle modification and placebo, in patients with NAFLD were included. The results from the NMA are presented as the weighted mean difference (WMD) of the continuous results and the corresponding 95% confidence intervals (95% CIs).

RESULTS

The articles presented the results of 49 trials involving 3,836 subjects published between 2013 and 2021. According to our results, thiazolidinedione (TZD) was ranked as the best diabetes medication in the reduction of alanine aminotransferase (ALT) (WMD = -10.10, 95% CI: -15.18, -5.01), followed by dipeptidyl peptidase-4 inhibitor (DPP4i) (WMD = -8.90, 95% CI: -14.41, -3.40). DPP4i also resulted in the greatest reduction in aspartate aminotransferase (AST) (WMD = -6.89, 95% CI: -11.72, -2.07). γ-Glutamyl transferase (γ-GT) reduction was highest in patients treated with glucagon-like peptide 1 receptor agonists (GLP1RAs) (WMD = -15.48, 95% CI: -30.93, -0.02). Ultimately, SGLT2is and GLP1RAs were superior to other diabetes medications or placebo in reducing liver fat fraction (LFF) (WMD = -6.09, 95% CI: -10.50, -1.68; WMD = -5.55, 95% CI: -10.40, -0.69, respectively).

CONCLUSION

Diabetes medications, including TZD, DPP4i and GLP1RAs, were found to be suitable alternatives for liver enzyme reduction in the treatment of NAFLD patients. SGLT2is are considered the most effective therapies for lipid modulation in these patients.

Combination Therapies for Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is considered a highly prevalent disease associated with various co-morbidities that lead to socioeconomic burden. Despite large-scale investigation, no pharmacological treatment has been approved specifically for NAFLD to date. Lifestyle modifications and diet are regarded as highly beneficial for the management of NAFLD, albeit with poor compliance, thus rendering pharmacological treatment highly important. Based on the current failure to discover a “magic bullet” to treat all patients with NAFLD and considering the multifaceted pathophysiology of the disease, combination therapies may be considered to be a rational alternative approach. In this regard, several drug categories have been considered, including, but not limited to, lipid-lowering, anti-hypertensive, glucose-lowering, anti-obesity, anti-oxidant, anti-inflammatory and anti-fibrotic medications. The aim of this review is, in addition to summarizing some of the multiple factors contributing to the pathophysiology of NAFLD, to focus on the efficacy of pharmacological combinations on the management of NAFLD. This may provide evidence for a more personalized treatment of patients with NAFLD in the future.

Non-alcoholic fatty liver disease in adults 2021: A clinical practice guideline of the Italian Association for the Study of the Liver (AISF), the Italian Society of Diabetology (SID) and the Italian Society of Obesity (SIO)

Nonalcoholic fatty liver disease (NAFLD) is a common and emerging liver disease in adults, paralleling the epidemic of obesity and diabetes and leading to worrisome events (hepatocellular carcinoma and end-stage liver disease). In the past years, mounting evidence added insights about epidemiology, natural history, diagnosis and lifestyle-based or drug treatment of NAFLD. In this rapidly evolving scenario, members of the Associazione Italiana per lo Studio del Fegato, the Società Italiana di Diabetologia and the Società Italiana dell'Obesità reviewed current knowledge on NAFLD. The quality of the published evidence is graded, and practical recommendations are made following the rules and the methodology suggested in Italy by the Centro Nazionale per l'Eccellenza delle cure and Istituto Superiore di Sanità. Whenever possible, recommendations are placed within the context the Italian Healthcare system, with reference to specific experience and local diagnostic and management resources.Level of evidence Level of evidence of recommendations for each PICO question were reported according to available evidence.

A Clinical Perspective of the Multifaceted Mechanism of Metformin in Diabetes, Infections, Cognitive Dysfunction, and Cancer

In type 2 diabetes, ecological and lifecourse factors may interact with the host microbiota to influence expression of his/her genomes causing perturbation of interconnecting biological pathways with diverse clinical course. Metformin is a plant-based or plant-derived medicinal product used for the treatment of type 2 diabetes for over 60 years and is an essential drug listed by the World Health Organization. By reducing mitochondrial oxidative phosphorylation and adenosine triphosphate (ATP) production, metformin increased AMP (adenosine monophosphate)-activated protein kinase (AMPK) activity and altered cellular redox state with reduced glucagon activity, endogenous glucose production, lipogenesis, and protein synthesis. Metformin modulated immune response by directly reducing neutrophil to lymphocyte ratio and improving the phagocytic function of immune cells. By increasing the relative abundance of mucin-producing and short-chain-fatty-acid-producing gut microbes, metformin further improved the host inflammatory and metabolic milieu. Experimentally, metformin promoted apoptosis and reduced proliferation of cancer cells by reducing their oxygen consumption and modulating the microenvironment. Both clinical and mechanistic studies support the pluripotent effects of metformin on reducing cardiovascular–renal events, infection, cancer, cognitive dysfunction, and all-cause death in type 2 diabetes, making this low-cost medication a fundamental therapy for individualization of other glucose-lowering drugs in type 2 diabetes. Further research into the effects of metformin on cognitive function, infection and cancer, especially in people without diabetes, will provide new insights into the therapeutic value of metformin in our pursuit of prevention and treatment of ageing-related as well as acute and chronic diseases beyond diabetes.

Sodium-glucose cotransporter protein-2 inhibitors and glucagon-like peptide-1 receptor agonists versus thiazolidinediones for non-alcoholic fatty liver disease: A network meta-analysis

AIMS

Non-alcoholic fatty liver disease (NAFLD) is a leading cause of chronic liver disorders worldwide. Some hypoglycemic drugs can improve NAFLD. However, it is unclear which of these types of hypoglycemic drugs are more effective for NAFLD. Therefore, we conducted a network meta-analysis to determine the effect of thiazolidinediones (TZDs), sodium-glucose cotransporter 2 (SGLT2) inhibitors, and glucagon-like peptide-1 (GLP-1) receptor agonists on NAFLD patients.

METHODS

A literature search of PubMed, EMBASE, the Cochrane Library, and Medline was conducted, and the literature from database inception up to April 30, 2021 was obtained. Liver function tests, lipid profiles, body mass index (BMI) and glycemic parameters were obtained from randomized controlled trials. Weighted mean differences (WMDs), relative risks and 95% confidence intervals (CIs) were calculated for continuous outcomes, and the I2 statistic was used to evaluate the heterogeneity of the studies.

RESULTS

In total, 22 trials, including 1361 patients, were selected. In direct meta-analysis, GLP-1 receptor agonists were superior to TZDs in decreasing alanine aminotransferase (WMD, -0.40, 95% CI: -0.60 to -0.20), γ-glutamyl transferase (WMD, -5.00, 95% CI: -6.47 to -3.53), BMI (WMD, -4.10, 95%CI: -6.55 to -1.65) and triglycerides (WMD, - 0.50, 95% CI: -0.68 to -0.32). Based on Bayesian network meta-analysis, the effect of SGLT-2 inhibitors on weight loss was superior to that of TZDs (WMD, -1.80, 95%CI: -3.30 to -0.41).

CONCLUSIONS

GLP-1 receptor agonists and SGLT-2 inhibitors improved liver enzymes, BMI, blood lipid, blood glucose and insulin resistance in NAFLD patients.

The Coexistence of Nonalcoholic Fatty Liver Disease and Type 2 Diabetes Mellitus

The incidence of nonalcoholic fatty liver disease (NAFLD) is growing worldwide. Epidemiological data suggest a strong relationship between NAFLD and T2DM. This is associated with common risk factors and pathogenesis, where obesity, insulin resistance and dyslipidemia play pivotal roles. Expanding knowledge on the coexistence of NAFLD and T2DM could not only protect against liver damage and glucotoxicity, but may also theoretically prevent the subsequent occurrence of other diseases, such as cancer and cardiovascular disorders, as well as influence morbidity and mortality rates. In everyday clinical practice, underestimation of this problem is still observed. NAFLD is not looked for in T2DM patients; on the contrary, diagnosis for glucose metabolism disturbances is usually not performed in patients with NAFLD. However, simple and cost-effective methods of detection of fatty liver in T2DM patients are still needed, especially in outpatient settings. The treatment of NAFLD, especially where it coexists with T2DM, consists mainly of lifestyle modification. It is also suggested that some drugs, including hypoglycemic agents, may be used to treat NAFLD. Therefore, the aim of this review is to detail current knowledge of NAFLD and T2DM comorbidity, its prevalence, common pathogenesis, diagnostic procedures, complications and treatment, with special attention to outpatient clinics.

Non-alcoholic fatty liver disease in adults 2021: A clinical practice guideline of the Italian Association for the Study of the Liver (AISF), the Italian Society of Diabetology (SID) and the Italian Society of Obesity (SIO)

Nonalcoholic fatty liver disease (NAFLD) is a common and emerging liver disease in adults, paralleling the epidemic of obesity and diabetes, and leading to worrisome events (hepatocellular carcinoma and end-stage liver disease). In the last years, mounting evidence added insights about epidemiology, natural history, diagnosis and lifestyle-based or drug treatment of NAFLD. In this rapidly evolving scenario, members of the Associazione Italiana per lo Studio del Fegato (AISF), the Società Italiana di Diabetologia (SID) and the Società Italiana dell'Obesità (SIO) reviewed current knowledge on NAFLD. The quality of the published evidence is graded, and practical recommendations are made following the rules and the methodology suggested in Italy by the Centro Nazionale per l'Eccellenza delle cure (CNEC) and Istituto Superiore di Sanità (ISS). Whenever possible, recommendations are placed within the context the Italian Healthcare system, with reference to specific experience and local diagnostic and management resources. Level of evidence: Level of evidence of recommendations for each PICO question were reported according to available evidence.

Non-alcoholic fatty liver disease in adults 2021: A clinical practice guideline of the Italian Association for the Study of the Liver (AISF), the Italian Society of Diabetology (SID) and the Italian Society of Obesity (SIO)

Nonalcoholic fatty liver disease (NAFLD) is a common and emerging liver disease in adults, paralleling the epidemic of obesity and diabetes, and leading to worrisome events (hepatocellular carcinoma and end-stage liver disease). In the last years, mounting evidence added insights about epidemiology, natural history, diagnosis and lifestyle-based or drug treatment of NAFLD. In this rapidly evolving scenario, members of the Associazione Italiana per lo Studio del Fegato (AISF), the Società Italiana di Diabetologia (SID) and the Società Italiana dell'Obesità (SIO) reviewed current knowledge on NAFLD. The quality of the published evidence is graded, and practical recommendations are made following the rules and the methodology suggested in Italy by the Centro Nazionale per l'Eccellenza delle cure (CNEC) and Istituto Superiore di Sanità (ISS). Whenever possible, recommendations are placed within the context the Italian Healthcare system, with reference to specific experience and local diagnostic and management resources. Level of evidence: Level of evidence of recommendations for each PICO question were reported according to available evidence.

Effectiveness of drug interventions in nonalcoholic fatty liver disease: A network meta-analysis

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a major chronic liver disorder worldwide, and there is no established treatment for this disease. We conducted a network meta-analysis (NMA) to compare existing treatments, which include four classes of antidiabetic drugs, and examined the optimum treatments for NAFLD.

AIM

To compare the effectiveness of different treatments for NAFLD.

METHODS

An NMA was conducted using Stata 14.0 (Corporation LLC, College Station, United States) and R (X64 3.6.3 version) in this study. Eligible randomized controlled trials (RCTs) were searched in the PubMed, Cochrane Library, Embase, Medline and Web of Science databases from database inception to April 2021. Two researchers independently screened the available studies in strict accordance with inclusion and exclusion criteria. The Cochrane Risk of Bias tool was used to evaluate the risk of bias of the included studies. The variables with and without dimensional differences were calculated as the standardized mean difference and weighted mean difference, respectively. An inconsistency model and “node-splitting” technique were used to test for inconsistency. Funnel plots were used to evaluate publication bias.

RESULTS

Twenty-two eligible RCTs involving 1377 participants were eventually included in our analysis. Data were pooled using a random-effects model. Our NMA results revealed that glucagon-like peptide-1 receptor agonists (GLP-1RAs) were the most effective treatment, yielding improvements in hepatic fat content (HFC), alanine aminotransferase (ALT), aspartate aminotransferase (AST), serum γ-glutamyl transferase (GGT) and body weight [surface under the cumulative ranking curve (SUCRA) = 99.6%, 92.6%, 82.8%, 92.3% and 99.6%, respectively], while thiazolidinediones (TZDs) were the best intervention for reducing the NAFLD activity score (NAS; SUCRA = 98.9%). In addition, moderate performance was observed for the sodium glucose cotransporter-2 inhibitors groups (SUCRA = 25.1%, 66.2%, 63.5%, 58.2% and 71.9% for HFC, ALT, AST, GGT and body weight, respectively). However, metformin performed poorly according to most indicators (SUCRA = 54.5%, 0.3%, 19.5%, 33.7%, 57.7% and 44.3% for HFC, NAS, ALT, AST, GGT and body weight, respectively).

CONCLUSION

GLP-1RAs may be the optimum choice for most patients with NAFLD. However, TZDs are considered the most effective therapies in NAFLD patients with histological disease activity.

Nonalcoholic Fatty Liver Disease (NAFLD) as Model of Gut-Liver Axis Interaction: From Pathophysiology to Potential Target of Treatment for Personalized Therapy

Nonalcoholic fatty liver disease (NAFLD) is the leading cause of liver disease worldwide, affecting both adults and children and will result, in the near future, as the leading cause of end-stage liver disease. Indeed, its prevalence is rapidly increasing, and NAFLD is becoming a major public health concern. For this reason, great efforts are needed to identify its pathogenetic factors and new therapeutic approaches. In the past decade, enormous advances understanding the gut-liver axis-the complex network of cross-talking between the gut, microbiome and liver through the portal circulation-have elucidated its role as one of the main actors in the pathogenesis of NAFLD. Indeed, evidence shows that gut microbiota is involved in the development and progression of liver steatosis, inflammation and fibrosis seen in the context of NAFLD, as well as in the process of hepatocarcinogenesis. As a result, gut microbiota is currently emerging as a non-invasive biomarker for the diagnosis of disease and for the assessment of its severity. Additionally, to its enormous diagnostic potential, gut microbiota is currently studied as a therapeutic target in NAFLD: several different approaches targeting the gut homeostasis such as antibiotics, prebiotics, probiotics, symbiotics, adsorbents, bariatric surgery and fecal microbiota transplantation are emerging as promising therapeutic options.

Nanomedicine for the treatment of diabetes-associated cardiovascular diseases and fibrosis

Cardiomyopathy and fibrosis are the main causes of heart failure in diabetes patients. For therapeutic purposes, a delivery system is required to enhance antidiabetic drug efficacy and specifically target profibrotic pathways in cardiomyocytes. Nanoparticles (NPs) have distinct advantages, including biocompatibility, bioavailability, targeting efficiency, and minimal toxicity, which make them ideal for antidiabetic treatment. In this review, we overview the latest information on the pathogenesis of cardiomyopathy and fibrosis in diabetes patients. We summarize how NP applications improve insulin and liraglutide efficacy and their sustained release upon oral administration. We provide a comprehensive review of the results of NP clinical trials in diabetes patients and of animal studies investigating the effects of NP-mediated anti-fibrotic treatments. Collectively, the application of advanced NP delivery systems in the treatment of cardiomyopathy and fibrosis in diabetes patients is a promising and innovative therapeutic strategy.

What proportion of people have a follow-up biopsy in randomized trials of treatments for non-alcoholic steatohepatitis?: A systematic review and meta-analysis

Background and aim

Trials of treatments for non-alcoholic steatohepatitis require endpoint assessment with liver biopsies. Previous large-scale trials have calculated their sample size expecting high retention but on average did not achieve this. We aimed to quantify the proportion of participants with a valid follow-up biopsy.

Methods

We conducted a systematic review of MEDLINE and Embase until May 2020 and included randomized clinical trials of any intervention in non-alcoholic steatohepatitis with at least 1-year follow-up. We were guided by Cochrane methods to run a meta-analysis with generalized linear mixed models with random effects.

Results

Forty-one trials (n = 6,695) were included. The proportion of participants with a valid follow-up biopsy was 82% (95%CI: 78%-86%, I² = 92%). There was no evidence of a difference by location, trial length, or by allocated treatment group. Reasons for missing follow-up biopsies were, in ranked order, related to participants (95 per 1,000 participants (95%CI: 69–129, I² = 92%), medical factors, protocol, trial conduct, and other/unclear. Biopsy-related serious adverse events occurred in 16 per 1,000 participants (95% CI: 8–33, I² = 54%). No biopsy-related deaths were reported.

Conclusions

The proportion of participants with a valid follow-up biopsy in therapeutic trials in non-alcoholic steatohepatitis is on average 82%, with around 1 in 10 participants declining a follow-up biopsy. These findings can inform adequately-powered trials.

Non-Alcoholic Fatty Liver Disease and Cardiovascular Comorbidities: Pathophysiological Links, Diagnosis, and Therapeutic Management

Non-alcoholic fatty liver disease (NAFLD) has a growing prevalence in recent years. Its association with cardiovascular disease has been intensively studied, and certain correlations have been identified. The connection between these two entities has lately aroused interest regarding therapeutic management. In order to find the best therapeutic options, a detailed understanding of the pathophysiology that links (NAFLD) to cardiovascular comorbidities is needed. This review focuses on the pathogenic mechanisms that are behind these two diseases and on the therapeutic management available at this time.

Effects of Metformin on Hepatic Steatosis in Adults with Nonalcoholic Fatty Liver Disease and Diabetes: Insights from the Cellular to Patient Levels

Nonalcoholic fatty liver disease (NAFLD) patients with diabetes constitute a subgroup of patients with a high rate of liver-related complications. Currently, there are no specific drug recommendations for these patients. Metformin, a conventional insulin sensitizer agent, has been widely prescribed in patients with diabetes. Metformin treatment has been shown to be effective at alleviating hepatic lipogenesis in animal models of NAFLD, with a variety of mechanisms being deemed responsible. To date, most studies have enrolled diabetic patients who are treated with metformin, with the drug being taken continuously throughout the study. Although evidence exists regarding the benefits of metformin for NAFLD in preclinical studies, reports on the efficacy of metformin in adult NAFLD patients have had some discrepancies regarding changes in liver biochemistry and hepatic fat content. Evidence has also suggested possible effects of metformin as regards the prevention of hepatocellular carcinoma tumorigenesis. This review was performed to comprehensively summarize the available in vitro, in vivo and clinical studies regarding the effects of metformin on liver steatosis for the treatment of adult NAFLD patients with diabetes. Consistent reports as well as controversial findings are included in this review, and the mechanistic insights are also provided. In addition, this review focuses on the efficacy of metformin as a monotherapy and as a combined therapy with other antidiabetic medications.

Diabetic fibrosis

Diabetes-associated morbidity and mortality is predominantly due to complications of the disease that may cause debilitating conditions, such as heart and renal failure, hepatic insufficiency, retinopathy or peripheral neuropathy. Fibrosis, the excessive and inappropriate deposition of extracellular matrix in various tissues, is commonly found in patients with advanced type 1 or type 2 diabetes, and may contribute to organ dysfunction. Hyperglycemia, lipotoxic injury and insulin resistance activate a fibrotic response, not only through direct stimulation of matrix synthesis by fibroblasts, but also by promoting a fibrogenic phenotype in immune and vascular cells, and possibly also by triggering epithelial and endothelial cell conversion to a fibroblast-like phenotype. High glucose stimulates several fibrogenic pathways, triggering reactive oxygen species generation, stimulating neurohumoral responses, activating growth factor cascades (such as TGF-β/Smad3 and PDGFs), inducing pro-inflammatory cytokines and chemokines, generating advanced glycation end-products (AGEs) and stimulating the AGE-RAGE axis, and upregulating fibrogenic matricellular proteins. Although diabetes-activated fibrogenic signaling has common characteristics in various tissues, some organs, such as the heart, kidney and liver develop more pronounced and clinically significant fibrosis. This review manuscript summarizes current knowledge on the cellular and molecular pathways involved in diabetic fibrosis, discussing the fundamental links between metabolic perturbations and fibrogenic activation, the basis for organ-specific differences, and the promises and challenges of anti-fibrotic therapies for diabetic patients.

Metformin and Fibrosis: A Review of Existing Evidence and Mechanisms

Fibrosis is a physiological response to organ injury and is characterized by the excessive deposition of connective tissue components in an organ, which results in the disruption of physiological architecture and organ remodeling, ultimately leading to organ failure and death. Fibrosis in the lung, kidney, and liver accounts for a substantial proportion of the global burden of disability and mortality. To date, there are no effective therapeutic strategies for controlling fibrosis. A class of metabolically targeted chemicals, such as adenosine monophosphate-activated protein kinase (AMPK) activators and peroxisome proliferator-activated receptor (PPAR) agonists, shows strong potential in fighting fibrosis. Metformin, which is a potent AMPK activator and is the only recommended first-line drug for the treatment of type 2 diabetes, has emerged as a promising method of fibrosis reduction or reversion. In this review, we first summarize the key experimental and clinical studies that have specifically investigated the effects of metformin on organ fibrosis. Then, we discuss the mechanisms involved in mediating the antifibrotic effects of metformin in depth.

Clinical implications, diagnosis, and management of diabetes in patients with chronic liver diseases

Diabetes mellitus (DM) negatively affects the development and progression of chronic liver diseases (CLD) of various etiologies. Concurrent DM and CLD are also associated with worse clinical outcomes with respect to mortality, the occurrence of hepatic decompensation, and the development of hepatocellular carcinoma (HCC). Unfortunately, early diagnosis and optimal treatment of DM can be challenging, due to the lack of established clinical guidelines as well as the medical complexity of this patient population. We conducted an exploratory review of relevant literature to provide an up-to-date review for internists and hepatologists caring for this patient population. We reviewed the epidemiological and pathophysiological associations between DM and CLD, the impact of insulin resistance on the progression and manifestations of CLD, the pathogenesis of hepatogenic diabetes, as well as the practical challenges in diagnosis and monitoring of DM in this patient population. We also reviewed the latest clinical evidence on various pharmacological antihyperglycemic therapies with an emphasis on liver disease-related clinical outcomes. Finally, we proposed an algorithm for managing DM in patients with CLD and discussed the clinical and research questions that remain to be addressed.

The Evaluation of Effective Drugs for the Treatment of Non-Alcoholic Fatty Liver Disease: A Systematic Review and Network Meta-Analysis

Purpose: Non-alcoholic fatty liver disease (NAFLD) and steatohepatitis are two forms of fatty liver disease with benign and malignant nature, respectively. These two conditions can cause an increased risk of liver cirrhosis and hepatocellular carcinoma. Given the importance and high prevalence of NAFLD, it is necessary to investigate the results of different studies in related scope to provide a clarity guarantee of effectiveness. Therefore, this systematic review and meta-analysis aim to study the efficacy of various medications used in the treatment of NAFLD. Methods: A systematic search of medical databases identified 1963 articles. After exclusion of duplicated articles and those which did not meet our inclusion criteria, eta-analysis was performed on 84 articles. Serum levels of alanine aminotransferase (ALT), aspartate amino transferase (AST) were set as primary outcomes and body mass index (BMI), hepatic steatosis, and NAFLD activity score (NAS) were determined as secondary outcomes. Results: Based on the P-score of the therapeutic effects on the non-alcoholic steatohepatitis (NASH), we observed the highest efficacy for atorvastatin, tryptophan, orlistat, omega-3 and obeticholic acid for reduction of ALT, AST, BMI, steatosis and NAS respectively. Conclusion: This meta-analysis showed that atorvastatin. life-style modification, weight loss, and BMI reduction had a remarkable effect on NAFLD-patients by decreasing aminotransferases.

Combined treatments with metformin and phosphodiesterase inhibitors alleviate nonalcoholic fatty liver disease in high-fat diet fed rats: a comparative study

Nonalcoholic fatty liver disease (NAFLD) is an excessive accumulation of fats in the liver resulting in hepatic inflammation and fibrous tissue formation along with insulin resistance. This study was designed to investigate the possible protective effects of metformin alone and in combination with different phosphodiesterase inhibitors (PDEIs). Rats were fed a high-fat diet (HFD) for 16 weeks to induce NAFLD. Starting from week 12, rats received metformin alone or in combination with pentoxifylline, cilostazol, or sildenafil. HFD administration resulted in hepatic steatosis and inflammation in rats. In addition, liver index, body composition index, activities of liver enzymes, and serum lipids deviated from normal. Further, significant elevations were recorded compared to control in terms of serum glucose, insulin, and HOMA-IR (homeostasis model assessment index for insulin resistance), oxidative stress parameters, hepatic TNF-α and NF-κB gene expression, and iNOS protein expression. Rats treated with metformin showed a significant improvement in the aforementioned parameters. However, the addition of pentoxifylline to metformin treatment synergized its action and produced a fortified effect against HFD-induced NAFLD better than other PDEIs. Data from this study indicated that combined treatment of metformin and pentoxifylline had the most remarkable ameliorated effects against HFD-induced NAFLD; further clinical investigations are needed to approve PDEIs for NAFLD treatment.

Noninvasive indices for predicting nonalcoholic fatty liver disease in patients with chronic kidney disease

BACKGROUND

Data on clinical characteristics of nonalcoholic fatty liver disease (NAFLD) in patients with chronic kidney disease (CKD) are scarce. We investigated the clinical features and risk factors of NAFLD using noninvasive serum markers in CKD patients and attempted the temporal validation of a predictive model for CKD based on NAFLD.

METHODS

This retrospective cross-sectional study was conducted in a single tertiary center. We enrolled 819 CKD patients and evaluated the predictive performance of relevant clinical and laboratory markers for the presence of NAFLD in both derivation (data from 2011 to 2014, n = 567) and validation (data from 2015 to 2016, n = 252) groups.

RESULTS

In the derivation group, NAFLD was observed in 89 patients (15.7%; mean body mass index (BMI), 24.6 kg/m2; median estimated glomerular filtration rate (eGFR), 28.0 ml/min). BMI, hemoglobin, serum alanine aminotransferase, eGFR, and triglyceride-glucose index were used to derive a prediction model for the presence of NAFLD. Using the cutoff value of 0.146, the area under the receiver operating characteristic curve (AUROC) for the prediction of NAFLD was 0.850. In the validation group, NAFLD was observed in 51 patients (20.2%; mean BMI, 25.4 kg/m2; median eGFR, 36.0 ml/min). Using the same prediction model and cutoff value, the AUROC was 0.842. NAFLD prevalence in CKD patients was comparable to that in the general population, increasing over time.

CONCLUSIONS

Our model using BMI, renal function, triglyceride-glucose index, serum alanine aminotransferase, and hemoglobin accurately predicted the presence of NAFLD in CKD patients.

Effect of Weight Loss Medications on Hepatic Steatosis and Steatohepatitis: A Systematic Review

Non-alcoholic fatty liver disease (NAFLD) is a common comorbidity in individuals with obesity. Although multiple pharmacotherapeutics are in development, currently there are limited strategies specifically targeting NAFLD. This systematic review summarizes the existing literature on hepatic effects of medications used for weight loss. Glucagon-like peptide 1 (GLP-1) agonists are the best-studied in this regard, and evidence consistently demonstrates reduction in liver fat content, sometimes accompanied by improvements in histological features of steatohepatitis and reductions in serum markers of hepatic injury such as alanine aminotransferase (ALT). It remains unclear whether these benefits are independent of the weight loss caused by these agents. Literature is limited regarding effects of orlistat, but a small number of reports suggest that orlistat reduces liver fat content and improves histologic features of NASH, benefits which may also be driven primarily by weight loss. A sizeable body of literature on hepatic effects of metformin yields mixed results, with a probability of modest benefit, but no consistent signal for strong benefit. There are insufficient data on hepatic effects of topiramate, phentermine, naltrexone, bupropion, and lorcaserin. Finally, a few studies to date suggest that sodium-glucose co-transporter-2 (SGLT2) inhibitors may reduce liver fat content and cause modest reductions in ALT, but further study is needed to better characterize these effects. Based on available data, GLP-1 agonists have the strongest evidence base demonstrating beneficial effects on NAFLD, but it is not clear if any weight loss medication has effects on NAFLD superior to those of nutritional modification and exercise alone.

Diabetes drugs for nonalcoholic fatty liver disease: a systematic review

BACKGROUND

Fatty liver is associated with obesity, type 2 diabetes, hyperlipidemia, hypertension, and metabolic syndrome. While there are no approved drugs for the treatment of nonalcoholic fatty liver disease (NAFLD) or nonalcoholic steatohepatitis, strategies to ameliorate fatty liver often target these related diseases. We sought to determine if any medications approved by the US Food and Drug Administration to treat diabetes are helpful in reducing weight and improving steatohepatitis in patients with NAFLD.

METHODS

We conducted a systematic review of published and unpublished studies evaluating the comparative effectiveness and harms of diabetes medications for the treatment of NAFLD. We searched MEDLINE, EMBASE, Cochrane Database of Systematic Reviews, and the Cochrane Central Register of Controlled Trials through 3rd quarter, 2019 using terms for included drugs and indications.

RESULTS

We screened 1591 citations and included 18 trials of diabetes drugs to treat NAFLD. Studies of metformin found no difference from placebo in steatosis, fibrosis, NAFLD activity score, or resolution of NASH. While weight and glucose control were improved with metformin, it did not substantially impact liver disease. Studies of pioglitazone in NASH patients found benefits in liver function, liver fat, and NASH resolution, though significant increases in weight may be cause for concern. Evidence for other thiazolinediones was more limited and had somewhat mixed results, but findings were generally consistent with those for pioglitazone: liver fat and function and glucose measures improved, but weight also increased. We found some evidence that liraglutide improves liver fat, liver function, and HbA1c and is effective at resolving NASH and reducing weight. Exenatide performed less well but also resulted in significant reductions in liver fat and weight.

CONCLUSIONS

Consistent with existing clinical practice guidelines, which recommend lifestyle intervention and treatment for comorbidities related to fatty liver disease as first-line treatment, trial evidence supports the efficacy of some diabetes drugs (especially pioglitazone) in patients with NAFLD or NASH, though weight gain with some diabetes drugs may warrant caution. Larger trials are needed to better characterize the efficacy and harms of diabetes pharmacotherapy in these patients.

Of mice and men: Is there a future for metformin in the treatment of hepatic steatosis?

Non-alcoholic fatty liver disease (NAFLD) encompasses a spectrum of liver diseases, of which the first stage is steatosis. It is one of the most common liver diseases in developed countries and there is a clear association between type 2 diabetes (T2DM) and NAFLD. It is estimated that 70% of people with T2DM have NAFLD and yet there is currently no licensed pharmacological agent to treat it. Whilst lifestyle modification may ameliorate liver fat, it is often difficult to achieve or sustain; thus, there is great interest in pharmacological treatments for NAFLD. Metformin is the first-line medication in the management of T2DM and evidence from animal and human studies has suggested that it may be useful in reducing liver fat via inhibition of lipogenesis and increased fatty acid oxidation. Findings from the majority of studies undertaken in rodent models clearly suggest that metformin may be a powerful therapeutic agent specifically to reduce liver fat accumulation; data from human studies are less convincing. In the present review we discuss the evidence for the specific effects of metformin treatment on liver fat accumulation in animal and human studies, as well as the underlying proposed mechanisms, to try and understand and reconcile the difference in findings between rodent and human work in this area.

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.

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.

Antidiabetic Drugs in NAFLD: The Accomplishment of Two Goals at Once?

Non-Alcoholic Fatty Liver Disease (NAFLD) is the most common cause of chronic liver disease in Western countries, accounting for 20–30% of general population and reaching a prevalence of 55% in patients with type 2 diabetes mellitus (T2DM). Insulin resistance plays a key role in pathogenic mechanisms of NAFLD. Many drugs have been tested but no medications have yet been approved. Antidiabetic drugs could have a role in the progression reduction of the disease. The aim of this review is to summarize evidence on efficacy and safety of antidiabetic drugs in patients with NAFLD. Metformin, a biguanide, is the most frequently used drug in the treatment of T2DM. To date 15 randomized controlled trials (RCTs) and four meta-analysis on the use of metformin in NAFLD are available. No significant improvement in histological liver fibrosis was shown, but it can be useful in the treatment of co-factors of NAFLD, like body weight, transaminase or cholesterol levels, and HbA1c levels. A possible protective role in various types of cancer has been reported for Metformin. Thiazolidinediones modulate insulin sensitivity by the activation of PPAR-γ. The RCTs and the meta-analysis available about the role of these drugs in NAFLD show an improvement in ballooning, lobular inflammation, and perhaps fibrosis, but some side effects, in particular cardiovascular, were showed. GLP-1 analogues stimulate insulin secretion by pancreatic beta cell and inhibit glucagon release; Liraglutide is the most used drug in this class and significantly improves steatosis, hepatocyte ballooning and transaminase levels. Scanty data about the role of DPP-4 and SGLT inhibitors were published. No data about insulin effects on NAFLD are available but it was showed a possible association between insulin use and the development of solid neoplasms, in particular HCC. In conclusion, antidiabetic drugs seem to be promising drugs, because they are able to treat both NAFLD manifestations and diabetes, preventing worsening of hepatic damage, but data are still conflicting. All antidiabetic drugs can be safely used in patients with compensated cirrhosis, while insulin is the preferred drug in decompensated Child C cirrhosis.

Evaluation of metformin therapy using controlled attenuation parameter and transient elastography in patients with non-alcoholic fatty liver disease

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is among the most common causes of liver disease worldwide. There is growing evidence on pathogenesis and pathophysiology of NAFLD. However, there is still no universally accepted pharmacotherapy protocol.

METHODS

The study was conducted on 42 patients with NAFLD. They were randomized to dietary treatment alone (n = 21) or to diet and metformin therapy (n = 21). Liver ultrasonography, controlled attenuation parameter (CAP), liver stiffness (LS), complete blood count, anthropometric and biochemical parameters were obtained before treatment (baseline), and after 3 and 5 months of the therapy.

RESULTS

Patients treated with diet and metformin exhibited significantly decreased CAP values at 3 and 5 months of the therapy compared to baseline (319 dB/m vs. 285 dB/m; p < 0.05; 319 dB/m vs. 295 dB/m; p < 0.05 respectively). Five months of diet and the metformin therapy resulted in significant reduction of LS value (6.2 kPa vs. 5.2 kPa; p <  0.05), while patients treated with diet alone had no significant changes in liver CAP and LS measurements.

CONCLUSIONS

Metformin therapy combined with dietary treatment seems to be effective for the reduction of hepatic steatosis and fibrosis. However, considering limitations of the study and inconsistent results of previous investigations in this area, there is a need for further research on metformin efficacy in this group of patients.

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.

Recommendations for the management of non-alcoholic fatty liver disease (NAFLD)

The Polish Group of Experts for Non-Alcoholic Fatty Liver Disease (PGE-NAFLD) is a multidisciplinary team of hepatology experts established by the Polish Association for the Study of Liver and the Polish Society of Epidemiology and Infectious Diseases. The recommendations for the management of non-alcoholic fatty liver disease have been developed by a group of experts in hepatology under the auspices of the Polish Association for the Study of Liver and the Polish Society of Epidemiology and Infectious Diseases. The recommendations are intended to help physicians understand the most current knowledge of NAFLD and apply it in clinical practice. Depending on the clinical situation, it may be necessary to individualize the management.

Randomised clinical trial: a leucine-metformin-sildenafil combination (NS-0200) vs placebo in patients with non-alcoholic fatty liver disease

BACKGROUND

Sirtuin 1 (Sirt1) is suppressed in non-alcoholic fatty liver disease (NAFLD), while its' stimulation or overexpression results in reduced disease severity in pre-clinical NAFLD models. Leucine allosterically activates Sirt1 and synergise with other Sirt/AMPK/NO pathway activators. We developed a triple combination of leucine, metformin and sildenafil (NS-0200), which was effective in a mouse model of non-alcoholic steatohepatitis (NASH).

AIM

To report the results from a Phase 2, randomised clinical trial of of NS-0200 in 91 subjects with NAFLD (liver fat ≥15% by magnetic resonance imaging-proton-density fat fraction (MRI-PDFF)).

METHODS

Subjects were randomised to placebo, low-dose (1.1 g leucine/0.5 g metformin/0.5 mg sildenafil) or high-dose NS-0200 (1.1 g leucine/0.5 g metformin/1.0 mg sildenafil) b.d. for 16 weeks; change in hepatic fat was assessed via MRI-PDFF, and lipid metabolism was assessed via changes in the lipidomic signature. Seventy subjects completed the trial and met a priori compliance criteria. Analyses were conducted on the full cohort and on those with alanine aminotransferase (ALT) values above median (50 U/L; n = 35).

RESULTS

In the full cohort, active treatments did not separate from placebo. High dose NS-0200 reduced hepatic fat by 15.7% (relative change from baseline) in the high ALT group (P < 0.005) while low dose NS-0200 and placebo did not significantly change hepatic fat. Lipidomic analysis showed dose-responsive treatment effects in both overall and high ALT cohorts, with significant decreases in metabolically active lipids and up-regulation of fatty acid oxidation.

CONCLUSION

These data support further evaluation of high-dose NS-0200 for treating NASH, especially in those with elevated ALT (NCT 02546609).

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.

Meta-Analysis of Randomized Controlled Trials of Pharmacologic Agents in Non-alcoholic Steatohepatitis

BACKGROUND

Currently, there is no standardized treatment regimen for non-alcoholic steatohepatitis.

AIM

We performed a metaanalysis of high quality randomized controlled trials that evaluated treatment response to metformin, thiazolidinediones (TZDs), and vitamin E in adult patients with non-alcoholic steatohepatitis. Outcome measures were improvement in liver histology, biochemical, and anthropometric measures.

MATERIAL AND METHODS

Nine trials met inclusion criteria (3 with TZD, 3 with Metformin, 2 with Vitamin E and 1 with both TZD and Vitamin E.).

RESULTS

With metformin, weighted liver histologic scores for steatosis, ballooning, and fibrosis did not demonstrate significant improvement and lobular inflammation worsened significantly (weighted mean increase 0.21, 95% CI 0.11 to 0.31, P < 0.0001). The liver histology score including steatosis (OR 3.51, 95% CI 2.14 to 5.78) and lobular inflammation (OR 2.65, 95% CI 1.69 to 4.15) improved with TZDs. Hepatic fibrosis (OR 1.58, 95% CI 0.98 to 2.54) and ballooning scores (OR 1.84, 95% CI 0.94 to 3.58) did not demonstrate significant improvement. With Vitamin E, weighted liver histologic scores for steatosis (weighted mean decrease -0.60, 95% CI -0.85 to -0.35, P < 0.0001), lobular inflammation (weighted mean decrease - 0.40, 95% CI -0.61 to -0.20, P = 0.0001) and ballooning (weighted mean decrease -0.30, 95% CI -0.54 to -0.07, P = 0.01) demonstrated significant improvement compared to placebo. Fibrosis did not significantly change.

CONCLUSION

In patients with NASH, TZDs and Vitamin E improve liver histologic scores but metformin does not. Insulin resistance also improves with both TZDs and metformin. Fibrosis does not improve with any of the agents.

Thiazolidinediones versus metformin on improving abnormal liver enzymes in patients with type 2 diabetes mellitus: a meta-analysis

Background

Liver enzyme abnormalities are common in patients with type 2 diabetes. Currently, the inverse relationship between elevated liver enzymes and antidiabetics intake may be explained by rigorous treatment and good control. However, few studies have directly explored the influence of antidiabetics on abnormal liver function, especially the comparison between two insulin sensitizers—thiazolidinediones and metformin.

Materials And Methods

Databases, including PubMed, Cochrane, CNKI, Wanfang and VIP were searched. Two reviewers performed independently. Meta-analysis was used when studies were homogeneous enough.

Results

Six studies, including 4726 patients with type 2 diabetes, were involved in this systematic review. Compared with metformin, thiazolidinediones significantly reduced the alanine transaminase, aspartate aminotransferase and gamma-glutamyl transpeptidase. Further subgroup analysis suggested that pioglitazone-treated participants showed vast improvement in decreasing alanine transaminase (MD = -13.70; 95% CI = -16.91 to -10.52; P < 0.00001; I² = 1%), aspartate aminotransferase (MD = -3.51; 95% CI = -5.74 to –1.28; P = 0.002; I² = 0%) and gamma-glutamyl transpeptidase (MD = -5.41; 95% CI = -9.40 to -1.42; P = 0.008; I² = 0%), while rosiglitazone exhibited no difference in lowering corresponding liver enzyme levels. Besides, thiazolidinediones similarly decreased fasting plasma glucose. However, thiazolidinediones were inferior to metformin in lowering HbA1C and alkaline phosphatase. Additionally, no significant publication bias was seen.

Conclusions

Thiazolidinediones may confer modest biological improvement of liver function in people with type 2 diabetes than metformin. But owing to the limited methodological quality, more clinical researches are warranted in the future.

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.

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.

The pharmacological management of NAFLD in children and adolescents

INTRODUCTION

Non-alcoholic fatty liver disease (NAFLD) represents a spectrum, including 'simple' steatosis, non-alcoholic steatohepatitis (NASH), and fibrosis. Increasing prevalence of NAFLD has followed the international rise in obesity and lifestyle modification is the mainstay therapy for children. To date, pharmacological trials have had varying efficacy but a large number of new agents are in early phase trials for adults. Areas covered: This review explores the effect of current and potential future paediatric NAFLD treatments in terms of histological and biochemical endpoints. The potential for the extension of adult treatments to children is discussed, as well as what limits the use of certain agents in children. Expert commentary: No drugs have yet to be licenced for NAFLD. Trial heterogeneity makes comparison of drugs between studies challenging. FXR agonists are yet to be trialled in children but may represent a safe and potentially efficacious therapy. Future treatments would likely encompass a multimodal approach that may include bariatric surgery.

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.

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.

The role of insulin resistance in nonalcoholic steatohepatitis and liver disease development--a potential therapeutic target?

Insulin resistance (IR) is defined by the inability of insulin to exert its metabolic actions, due to impaired activation of intracellular insulin signaling. This condition is caused by genetic defects or by environmental conditions, among which the most common is obesity. Systemic IR determines the development of hepatic fat accumulation, which can progress to nonalcoholic steatohepatitis, cirrhosis and hepatocellular carcinoma, and is a major determinant of liver disease independently of coexisting factors. Therefore, insulin-sensitizing drugs are currently under evaluation to improve steatohepatitis. Indeed, manipulation of nuclear hormone receptors is already under scrutiny for liver disease prevention by amelioration of IR, whereas NOTCH signaling inhibition represents a novel approach. Nevertheless, further research is warranted to better understand the mechanism linking IR to progressive fibrogenesis in the absence of inflammation and to identify novel drug targets.

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.

Comparative efficacy of anti-diabetic agents on nonalcoholic fatty liver disease in patients with type 2 diabetes mellitus: a systematic review and meta-analysis of randomized and non-randomized studies

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) has a high prevalence in patients with type 2 diabetes mellitus (T2DM). In this study, we sought to provide a comprehensive assessment regarding the effects of anti-diabetic agents on NAFLD in patients with T2DM.

METHODS

MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials were searched for randomized controlled trials (RCTs) with different anti-diabetic agents in T2DM. Observational trials were also recruited to expand our population. Hepatic fat content and liver histology were evaluated as primary outcomes. Pooled estimates were calculated using a fixed effect model.

RESULTS

One thousand one hundred ninety-six participants in 19 RCTs and 14 non-randomized studies were included. Evidence from RCTs and observational studies suggested that greater hepatic fat content reduction and improved liver histology were seen in thiazolidinediones for 12-72 weeks; glucagon-like peptide-1 receptor agonists had beneficial effects on hepatic fat content after 26-50 weeks intervention, and insulin/metformin combination with 3-7 months improved hepatic fat content. Initiating metformin or dapagliflozin showed no benefit on hepatic fat content or liver histology in 16-48 weeks. Besides, nateglinide for 18 months was reported in a small sample-size RCT to improve hepatic fat content and liver histology. Sitagliptin therapy of 1 year also provided benefit on nonalcoholic steatohepatitis score in an observational study.

CONCLUSIONS

For T2DM with NAFLD, administrating thiazolidinediones and glucagon-like peptide-1 receptor agonists seems to provide more identified advances in attenuating hepatic fat content. Further RCTs are warranted to assess the efficacy of various hypoglycemic agents on clinical outcomes associated with NAFLD in T2DM. Copyright © 2015 John Wiley & Sons, Ltd.