Impact of diabetes on the severity of liver disease

The prevalence of type 2 diabetes is higher in patients who have liver diseases, such as nonalcoholic fatty liver disease, chronic viral hepatitis, hemochromatosis, alcoholic liver disease, and cirrhosis. The development of diabetes in patients with cirrhosis is well recognized, but evidence is emerging that the development of chronic liver disease and progression to cirrhosis may occur after the diagnosis of diabetes and that diabetes plays a role in the initiation and progression of liver injury. This article provides an overview of the evidence for an increased prevalence of diabetes in a range of liver diseases; the effect of diabetes on the severity of disease; the potential mechanisms whereby coexistent diabetes exacerbates progression of hepatic fibrosis; and the impact of obesity, insulin resistance, and type 2 diabetes on clinical outcomes.     

Nonalcoholic Fatty Liver Disease: A Clinical Review

Nonalcoholic fatty liver disease may be the most common liver disease in the United States, with a high prevalence in the obese, type 2 diabetic population, and it is probably underestimated as a cause for cirrhosis. Clinicopathologically, it represents a wide spectrum of histologic abnormalities and clinical outcomes, ranging from benign hepatic steatosis to cirrhosis. Pathophysiologically, insulin resistance is thought to be pivotal in the development of steatosis, after which a second oxidative stressor produces lipid peroxidation and nonalcoholic steatohepatitis (NASH). Liver biopsy is the gold standard for diagnosis and prognosis. The need for an effective treatment is both clear and urgent, yet in the absence of proven therapies, treatment is directed toward weight loss and comorbidity management. For patients with NAFLD at risk of disease progression, there is a lack of large, randomized, placebo-controlled trials of adequate treatment duration, with baseline stratification according to histologic severity.     

Diabetes und Leberzirrhose

Disturbances of glucose metabolism, such as glucose intolerance or hepatogenous diabetes frequently occur in patients with liver cirrhosis and are caused by functional hepatocellular loss and insulin resistance due to chronic liver disease. Until now there have been no recommendations comparable to guidelines on the diagnosis and therapy of hepatogenous diabetes. Regarding basic treatment a sufficient daily energy and protein supply should be guaranteed as the majority of patients with liver cirrhosis are malnourished. The risk of hypoglycemia must be carefully considered under pharmacological treatment of hepatogenous diabetes. Suitable oral antidiabetics are glinides, dipeptidyl peptidase-4 (DPP4) inhibitors and glucagon-like peptide-1 (GLP1) analogues; however, no data from clinical studies are available so far. If a sufficient diabetes adjustment cannot be achieved by oral antidiabetics, prandial insulin therapy using short acting insulin or rapidly acting insulin analogues should be applied. Optimization of diabetic metabolic conditions is not only important to avoid typical late diabetic complications but also cirrhosis-associated complications, e. g. gastrointestinal bleeding, hepatic encephalopathy or the occurrence of hepatocellular carcinoma.     

Managing diabetes and liver disease association

There is strong association between liver diseases and diabetes (DM) which is higher than expected by a chance association of two very common disorders. It can be classified into three categories: Liver disease related to diabetes, hepatogenous diabetes (HD), and liver disease occurring coincidentally with DM. The criteria for the diagnosis of diabetes associating liver disease are the same for primary diabetes. Two hours post glucose load is a better screening test for HD. HbA1c may not be suitable for diagnosis or monitoring of diabetes associating advanced liver disease. Apart from the increased cardiovascular risk in patients with type 2 DM (T2 DM) and NAFLD, the cardiovascular and retinopathy risk is low in HD. Patients with metabolic derangement should be screened for NAFLD which in turn may predict T2 DM development. Similarly, patients with established T2 DM should also be screened for NAFLD which further contributes to diabetes worsening.Diabetes is a significant risk factor for progression of the chronic liver disease. It is associated with poor patient survival.Treatment of diabetes associating liver disease appears beneficial. Metformin, if tolerated and not contraindicated, is recommended as a first-line therapy for patients with diabetes and chronic liver disease (CLD). If the hepatic disease is severe, insulin secretagogues should be avoided because of the increased risk of hypoglycaemia. Pioglitazone may be useful in patients with fatty liver disease. DPP-4 inhibitors showed effectiveness and safety for the treatment of T2 DM in CLD patients up to those with child B stage. GLP-1 receptor agonists and SGLT-2 inhibitors exhibit positive effects on weight and are associated with minimal risk of hypoglycaemia. Insulin must be used with caution, as hypoglycaemia may be a problem. Insulin analogues are preferred in the context of hypoglycaemiaStatins can be used to treat dyslipidaemia in NAFLD, also the use of angiotensin II receptor antagonist for hypertension is safe and beneficialGiven the clear association between diabetes mellitus and hepatocellular carcinoma, the strict control of glycaemia with insulin sensitizers can be essential in its prevention.The addition of DM to the currently used scores (Child-Pugh and MELD scores) may enhance the sensitivity and the specificity for prediction of morbidity and mortality rates in cirrhotic patients.In the new era of directly acting antiviral agents (DAAs) for HCV treatment, it is recommended to follow up lipid profile and blood sugar levels following SVR in order to adjust doses of medications used in diabetic (SVR is associated with reduction in insulin requirements) and dyslipidaemic patients (rebound increase in the lipid profile after clearing the virus may increase risk of cardiovascular disease (CVD)). The issues of post liver transplant diabetes and relation between DM and chronic HBV are highlighted.This narrative review and Consensus-based practice guidance (under revision and criticism) are based on a formal review and analysis of the recently published world literature on the topic (Medline search up to September 2017); and the experience of the authors and independent reviewers.     

Carbohydrate metabolism dysregulation in cirrhosis: pathophysiology, prognostic impact and therapeutic implications

The liver plays a key-role in carbohydrates metabolism. Glucose intole-rance, overt diabetes mellitus and insulin resistance are characteristic features of patients with cirrhosis. Central hyperinsulinemia and peripheral insulin-resistance are the main explanations for the high prevalence of diabetes in patients with cirrhosis. On the other hand, type 2 diabetes is associated with a wide spectrum of liver diseases ranging from nonalcoholic fatty liver to cirrhosis and hepatocellular carcinoma. Carbohydrate metabolism abnormalities are a major aggravating risk factor in cirrhosis. Diabetes is also an independent negative prognostic factor in cirrhotic patients. This leads to specific diagnostic procedures and therapeutic issues. Patients with diabetes and liver disease frequently need insulin treatment. The presence of liver disease makes the treatment of diabetes complex, and additional research is needed to determine the best treatment strategies in these patients.     

Incretin based therapies: A novel treatment approach for non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease is considered a hepatic manifestation of metabolic syndrome (MS). The current treatment of non-alcoholic fatty liver disease (NAFLD) principally includes amelioration of MS components by lifestyle modifications but the lack of success in their implementation and sustainment arises the need for effective pharmacological agent in fatty liver treatment. Incretins are gut derived hormones secreted into the circulation in response to nutrient ingestion that enhances glucose-stimulated insulin secretion. Glucagon-like peptide-1 (GLP-1) is the most important incretin. Its receptor agonist and inhibitors of dipeptidyl peptidase-4 (DPP-4) are used in treatment of type 2 diabetes mellitus. DPP-4 serum activity and hepatic expression are shown to be elevated in several hepatic diseases. There are several experimental and clinical trials exploring the efficacy of incretin based therapies in NAFLD treatment. They suggest that GLP-1 analogues might have beneficial effect on hepatic steatosis acting as insulin sensitizers and directly by stimulating GLP-1 receptors expressed on hepatocytes. The use of DPP-4 inhibitors also results in hepatic fat reduction but the mechanism of action remains unclear. There is growing evidence that incretin based therapies have beneficial effects on hepatocytes, however further study analysis are needed to assess the long term effect of incretin based therapies on NAFLD.     

Role of nonalcoholic fatty liver disease in the development of insulin resistance and diabetes

Nonalcoholic fatty liver disease (NAFLD) is a common disease that is usually accompanied by insulin resistance (IR). Whether or how NAFLD and IR are temporally and mechanistically related is controversial. Recent studies focus on their epidemiology, the importance of dietary fat, the role of adipocytokines and the sterol regulatory element-binding protein-1c. NAFLD and IR may progress to severe diseases, such as cirrhosis, diabetes or both, and understanding the pathogenesis of the precursor conditions has preventive and therapeutic implications. This review focuses on the possible relationships between NAFLD and IR and the treatment options available.     

Remission of active diabetic hepatitis after correction of hyperglycemia

²Department of Pathology, Academic Medical Center, Amsterdam, The Netherlands ABSTRACT— A 60-year-old obese woman with type II diabetes mellitus and hepatomegaly exhibited progression of steatosis to hepatitis and cirrhosis. The patient was treated with large amounts of insulin combined with sulfonylurea, resulting in correction of the hyperglycemia. In the subsequent 9 months, weight loss did not occur, whereas insulin therapy could be discontinued. The liver decreased in size, and liver tests normalized. We suggest that intensive treatment of hyperglycemia may result in reversal of insulin resistance in patients with diabetic liver disease, while correction of hyperglycemia can lead to resolution of the hepatic abnormalities associated with diabetes mellitus.     

Insulin resistance and clinical aspects of non-alcoholic steatohepatitis (NASH).

Non-alcoholic steatohepatitis (NASH) is one of the most common liver disorders. This is highly prevalent in obese and diabetic subjects. Persons with central obesity are at particular risk. Other clinical predictors are age more than 40-50 years and hyperlipidemias, but none of these factors is invariable for causation of NASH. Other reported associations are, celiac disease, Wilson's Disease and few other metabolic diseases. Drugs, particularly amiodarone, tamoxifen, nucleoside analogues and methotrxate have also been linked to NASH. The disease is evenly distributed in both sexes but advanced disease is more common in women. Ethnic variation exists and African Americans are less affected than Hispanic Americans. Specific clinical features of NASH are infrequent. Patients usually come to clinical attention by elevated liver enzymes found on routine evaluation but on history, about two third of patients will admit to have mild fatigue and about half will report right upper quadrant pain. Rarely, patient may present with a complication of cirrhosis. Physical examination may reveal hepatomegaly and splenomegaly. Research in last few years has stressed that development of steatosis, stetohepatitis, fibrosis with subsequent cirrhosis are most probably the result of insulin resistance. Therefore, clinical features may reflect existence of insulin resistance. Obesity, particularly central obesity is most important of these. Patients may have sleep apnea syndrome. Hypertension and manifestations of diabetes mellitus like polyuria, polydypsia, and neurological deficits may occur. Patients may have varying combination of obesity, diabetes, hyperlipidemia, hypertension and impaired fibrinolysis (syndrome X). Children with insulin resistance may show acanthosis nigricance. Patients with polycystic ovary syndrome, which consists of insulin resistance, diabetes, obesity, hirsutism, oligo or polymenorrha and hyperlipidemia may have NASH. Other rare manifestations of insulin resistance, which can be seen in patients of NASH are lipomatosis, lipoatrophy/lipodystrophy and panniculitis. Most other rare conditions known to cause NASH like peroxisomal diseases, mitochondialpathies, Weber-Christian disease, Mauriac syndrome, Madelung's lipomatosis and abetaliopprotenemia also have insulin resistance. This is believed that primary defect underlying insulin resistance is impairment in postreceptor pathways (through tyrosine kinase activity) of insulin action. Primary defect in insulin receptors appear uncommon. This results in down regulation of insulin receptor substance 1 (IRS-1) signaling by excess free fatty acids. In muscle, activated IRS-1 promotes translocation of glucose transporter protein 4 (GLUT4) to cell membrane. As a result, monocyte glucose uptake by GLUT4 increases glucose disposal from blood and reduced need for insulin. PKC-0 is a likely candidate as serine kinase in muscle regulated by fatty acids that can impair the activation of IRS-1. Insulin resistance is usually evaluated by fasting insulin levels, Quantitative Insulin Check Index (QUICKI) and Homeostasis Model Assessment of Insulin Resistance (HOMA), C-peptid/insulin ratio oral glucose tolerance test and hyper insulinemic euglycemic clamp. The clamp technique is considered the gold standard.     

二肽基肽酶-4在慢性肝病发病中的作用研究进展

二肽基肽酶-4（DPP-4）是膜相关酶,又称T细胞表面抗原CD26,在体内广泛分布,作用广泛。最有代表的作用靶肽是胰高血糖素样肽（GLP）-1,而GLP-1的失活导致糖耐量减低和糖尿病。除了其肽酶作用之外,DPP-4与免疫激活密切相关,结合并降解细胞外基质,对抗抗癌剂以及脂质积累。最近的研究表明,肝脏表达高水平的DPP-4,DPP-4在各种慢性肝病（如丙型肝炎病毒感染、非酒精性脂肪性肝病和肝细胞癌）的发病中有一定的作用。此外,在肝脏,干细胞也表达DPP-4,提示其在肝移植中有重要作用。本文介绍了DPP-4的分布及生物活性,重点讨论了DPP-4在慢性肝病发病中的作用以及DPP-4抑制剂的临床应用前景。     

Non-alcoholic fatty liver disease in Malaysia: a demographic, anthropometric, metabolic and histological study

BACKGROUND AND OBJECTIVES: Nonalcoholic fatty liver disease (NAFLD) is increasing rapidly in the Asia–Pacific region. There has been a paucity of studies from the region. The aims of this study were to define the demographic, anthropometric, metabolic and histological characteristics of patients with NAFLD in our local population and to determine independent predictors of severe liver fibrosis. METHODS: Patients with persistently raised liver enzymes and/or fatty liver detected on ultrasonography with exclusion of other liver disorders were prospectively recruited. Their insulin resistance was assessed using the homeostasis model assessment of insulin resistance score. A liver biopsy was performed in all cases for grading (for steatohepatitis) and staging (for fibrosis) of NAFLD. Independent risk factors for fibrosis were determined using multiple logistic regression analysis. RESULTS: Seventy‐five patients were recruited: 39 men (52%) and 36 women (48%). The mean age of the patients was 47.0 ± 12.2 years. Of these, 58 patients (77.3%) were centrally obese, 29 patients (38.7%) were diabetic and 15 patients (20.0%) had impaired glucose tolerance. Insulin resistance was diagnosed in 62 out of 64 (96.9%) patients. Benign steatosis, nonalcoholic steatohepatitis and cirrhosis were diagnosed in three (4.3%), 59 (84.3%) and eight (11.4%) of 70 patients, respectively. Significant independent predictors of liver fibrosis were; male sex (P = 0.019, OR = 5.55, CI = 1.33–23.18) and Indian race (P = 0.013, OR = 8.21, CI = 1.56–43.16). CONCLUSIONS: The full histological spectrum of NAFLD was seen in our patients. The majority of patients were insulin resistant, centrally obese and either diabetic or had impaired glucose tolerance. The predictors of severe liver fibrosis were male sex and Indian race.     

The treatment of diabetes mellitus of patients with chronic liver disease

About 80% of patients with liver cirrhosis may have glucose metabolism disorders, 30% show overt diabetes mellitus (DM). Prospective studies have demonstrated that DM is associated with an increased risk of hepatic complications and death in patients with liver cirrhosis. DM might contribute to liver damage by promoting inflammation and fibrosis through an increase in mitochondrial oxidative stress mediated by adipokines. Based on the above mentioned the effective control of hyperglycemia may have a favorable impact on the evolution of these patients. However, only few therapeutic studies have evaluated the effectiveness and safety of antidiabetic drugs and the impact of the treatment of DM on morbidity and mortality in patients with liver cirrhosis. In addition, oral hypoglycemic agents and insulin may produce hypoglycemia and lactic acidosis, as most of these agents are metabolized by the liver. This review discusses the clinical implications of DM in patients with chronic liver disease. In addition the effectiveness and safety of old, but particularly the new antidiabetic drugs will be described based on pharmacokinetic studies and chronic administration to patients. Recent reports regarding the use of the SGLT2 inhibitors as well as the new incretin-based therapies such as injectable glucagon-like peptide-1 (GLP-1) receptor agonists and oral inhibitors of dipeptidylpeptidase-4 (DPP-4) will be discussed. The establishment of clear guidelines for the management of diabetes in patients with CLD is strongly required.     

Potential mechanisms linking gut microbiota and portal hypertension

Gut microbiota is the largest collection of commensal micro‐organisms in the human body, engaged in reciprocal cellular and molecular interactions with the liver. This mutually beneficial relationship may break down and result in dysbiosis, associated with disease phenotypes. Altered composition and function of gut microbiota has been implicated in the pathobiology of nonalcoholic fatty liver disease (NAFLD), a prevalent condition linked to obesity, insulin resistance and endothelial dysfunction. NAFLD may progress to cirrhosis and portal hypertension, which is the result of increased intrahepatic vascular resistance and altered splanchnic circulation. Gut microbiota may contribute to rising portal pressure from the earliest stages of NAFLD, although the significance of these changes remains unclear. NAFLD has been linked to lower microbial diversity and weakened intestinal barrier, exposing the host to bacterial components and stimulating pathways of immune defence and inflammation. Moreover, disrupted host‐microbial metabolic interplay alters bile acid signalling and the release of vasoregulatory gasotransmitters. These perturbations become prominent in cirrhosis, increasing the risk of clinically significant portal hypertension and leading to bacterial translocation, sepsis and acute‐on‐chronic liver failure. Better understanding of the gut‐liver axis and identification of novel microbial molecular targets may yield specific strategies in the prevention and management of portal hypertension.     

Diabetes and liver disease: an ominous association

Diabetes mellitus and advanced liver disease are associated with each other more frequently than expected by chance, and such an association carries a significant risk of morbidity and mortality. A metabolic pathway leading to advanced liver disease via fatty liver and steatohepatitis has been demonstrated, further supporting the possibility that cirrhosis may be a late complication of diabetes. In addition, an interaction between hepatitis C virus (HCV) and insulin resistance increases the overall prevalence of associated diseases, through largely unidentified mechanisms. Extensive prospective monitoring of non-alcoholic fatty liver disease cases, analysis of insulin signaling in HCV-infected patients using molecular biology techniques, and intervention studies, will help to clarify the mechanisms of action of the possible clinical strategies, the predictive value of biochemical, histological, and clinical markers, and the effectiveness of treatments available.     

Crosstalk between nonalcoholic fatty liver disease and cardiometabolic syndrome

Nonalcoholic fatty liver disease (NAFLD) is a chronic condition characterized by fat accumulation combined with low‐grade inflammation in the liver. A large body of clinical and experimental data shows that increased flux of free fatty acids from increased visceral adipose tissue and de novo lipogenesis can lead to NAFLD and insulin resistance. Thus, individuals with obesity, insulin resistance, and dyslipidaemia are at the greatest risk of developing NAFLD. Conversely, NAFLD is a phenotype of cardiometabolic syndrome. Notably, researchers have discovered a close association between NAFLD and impaired glucose metabolism and focused on the role of NAFLD in the development of type 2 diabetes. Moreover, recent studies provide substantial evidence for an association between NAFLD and atherosclerosis and cardiometabolic disorders. Even if NAFLD can progress into severe liver disorders including nonalcoholic steatohepatitis (NASH) and cirrhosis, the majority of subjects with NAFLD die from cardiovascular disease eventually. In this review, we propose a potential pathological link between NAFLD/NASH and cardiometabolic syndrome. The potential factors that can play a pivotal role in this link, such as inflammation, insulin resistance, alteration in lipid metabolism, oxidative stress, genetic predisposition, and gut microbiota are discussed.     

Hepatogener Diabetes

Background

Disturbances of glucose metabolism are common in chronic liver disease and about 30–40?% of patients with liver cirrhosis develop type 2 diabetes. The diabetes may be a direct consequence of the hepatic disease due to excessive insulin resistance or may be caused by classical type 2 diabetes.

Blood glucose determination

Patients with chronic liver disease frequently have a normal fasting glucose despite manifest type 2 diabetes with postprandial excessive increases in glucose. Therefore, oral glucose tolerance tests should be performed after diagnosis of hepatic cirrhosis.

Prognosis

Diabetes mellitus is associated with increased mortality and an increased risk of complications of liver cirrhosis including premature death, hepatocellular carcinoma, hepatic encephalopathy, and spontaneous bacterial peritonitis. Therapy of diabetes should include metformin and α?glucosidase inhibitors which can reduce the risk of these complications. Therefore, the diagnosis of diabetes has important consequences in chronic liver disease.

     

Recent advances in dietary supplementation,in treating non-alcoholic fatty liver disease

Nonalcoholic fatty liver disease(NAFLD) is currently known as the most common liver problem, characterized by excessive lipid accumulation in hepatocytes,which may progress to other liver diseases such as nonalcoholic steatohepatitis, hepatic tissue fibrosis, livercirrhosis, and failure or hepatocellular carcinoma. Since NAFLD is positively associated with the development of obesity, insulin resistance, and ultimately type 2 diabetes mellitus, it is often regarded as the hepatic manifestation of the metabolic syndrome. No pharmacologic treatment has yet been proven for this disease. For most patients with presumed or confirmed NAFLD, the only proven strategy is to offer lifestyle advice that can lead to sustained weight loss. Since insulin resistance, oxidative stress, inflammation, and necro-apoptosis are involved in NAFLD pathogenesis, it seems that every potential therapeutic agent should target one or some of these pathologic events. There are many well known anti-oxidants, anti-inflammatory, and insulin sensitizer dietary supplements which have shown beneficial effects on NAFLD improvement in animal and human studies. The purpose of this review is to explore the existing evidences on dietary supplements considered to have hepatoprotective properties, and to present some proposed mechanisms by which they may protect against NAFLD.     

Is there any link between dietary pattern and development of nonalcoholic fatty liver disease in adolescence? An expert review

Evaluation of: Oddy WH, Herbison CE, Jacoby P et al. The western dietary pattern is prospectively associated with nonalcoholic fatty liver disease in adolescence. Am. J. Gastroenterol. 108, 778–785 (2013).

The prevalence of overweight and obesity in childhood is a major public health concern. According to the obesity trend, the prevalence of pediatric nonalcoholic fatty liver disease (NAFLD) is also increasing. Nonalcoholic fatty liver disease is characterized by a spectrum of hepatic lesions (i.e., steatosis, ballooning, necroinflammation and fibrosis) that can progress to cirrhosis, hepatocellular carcinoma and liver failure with the consequent need for liver transplantation. Pediatric NAFLD is typically of primary origin and it is strongly associated with several features of the metabolic syndrome such as obesity, insulin resistance, dyslipidemia and Type 2 diabetes. The evaluated article reports the prospective relationship between dietary patterns at age 14 years and the presence of NAFLD at age 17 years. A total of 995 adolescents completed a food frequency questionnaire at 14 years and had liver ultrasound at 17 years. Prospective associations between the dietary pattern scores and the risk of NAFLD were analyzed using multiple logistic regression analyses. Nonalcoholic fatty liver disease was present in 15.2% of adolescents. A healthy dietary pattern at 14 years appeared protective against NAFLD at 17 years in centrally obese adolescents. On the contrary, a western dietary pattern at 14 years in this cohort was associated with an increased risk of NAFLD at 17 years, particularly in obese adolescents.     

Tumor necrosis factor alpha promoter polymorphisms and insulin resistance in nonalcoholic fatty liver disease

BACKGROUND & AIMS: Nonalcoholic fatty liver disease, which can range from fatty liver alone to nonalcoholic steatohepatitis and cirrhosis, is related to insulin resistance. Tumor necrosis factor alpha (TNF-alpha) may induce insulin resistance, and polymorphisms of its promoter have been associated with an increased release of this cytokine. We analyzed (1) the prevalence of insulin resistance, (2) the prevalence of the 238 and 308 TNF-alpha polymorphisms, and (3) the relationship among TNF-alpha polymorphisms, insulin resistance, and the occurrence of steatohepatitis in 99 patients with nonalcoholic fatty liver diagnosed by ultrasonography and confirmed by histologic analysis in the 53 who underwent biopsy. METHODS: Insulin resistance was evaluated by the homeostatic metabolic assessment insulin resistance indices and TNF-alpha polymorphisms by polymerase chain reaction and restriction fragment length polymorphism analysis. RESULTS: Insulin resistance was detected in almost all of the patients and was more severe in those with steatohepatitis. The prevalence of the 238, but not of the 308, TNF-alpha polymorphism was higher in subjects with nonalcoholic fatty liver than in controls (31% vs. 15%; P < 0.0001), and patients positive for TNF-alpha polymorphisms had higher insulin resistance indices, a higher prevalence of impaired glucose tolerance, and a lower number of associated risk factors for steatosis. CONCLUSIONS: TNF-alpha polymorphisms could represent a susceptibility genotype for insulin resistance, nonalcoholic fatty liver, and steatohepatitis.     

Pathogenesis and therapeutic approaches for non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease affects approximately one-third of the population worldwide, and its incidence continues to increase with the increasing prevalence of other metabolic disorders such as type 2 diabetes. As non-alcoholic fatty liver disease can progress to liver cirrhosis, its treatment is attracting greater attention. The pathogenesis of non-alcoholic fatty liver disease is closely associated with insulin resistance and dyslipidemia, especially hypertriglyceridemia. Increased serum levels of free fatty acid and glucose can cause oxidative stress in the liver and peripheral tissue, leading to ectopic fat accumulation, especially in the liver. In this review, we summarize the mechanism underlying the progression of hepatic steatosis to steatohepatitis and cirrhosis. We also discuss established drugs that are already being used to treat non-alcoholic fatty liver disease, in addition to newly discovered agents, with respect to their mechanisms of drug action, focusing mainly on hepatic insulin resistance. As well, we review clinical data that demonstrate the efficacy of these drugs, together with improvements in biochemical or histological parameters.