The effects of rosiglitazone, metformin, and diet with exercise in nonalcoholic fatty liver disease

Review of current and new drugs for the treatment of metabolic-associated fatty liver disease

In the past 3 decades, metabolic-associated fatty liver disease (MAFLD) has emerged as a widespread liver condition, with its global prevalence on the rise. It ranks as a leading contributor to hepatocellular carcinoma (HCC) and necessitates liver transplantation. Under the multiple parallel hits model, the pathogenesis of MAFLD stems from various liver stressors, notably nutrient overload and sedentary lifestyles. While medical management for MAFLD is well-established, encompassing non-pharmaceutical and pharmaceutical interventions, determining the most effective pharmaceutical therapy has remained elusive. This review discusses diabetic medications for MAFLD treatment, emphasizing recent studies and emerging drugs while reviewing other nondiabetic agents. Emerging evidence suggests that combination therapies hold promise for resolving MAFLD and metabolic steatohepatitis (MASH) while managing side effects. Ongoing trials play a pivotal role in elucidating the effects of mono, dual, and triple receptor agonists in individuals with MASH. With the rising burden of MAFLD/MASH and its severe consequences, the need for effective treatments is more pressing than ever. This review provides a comprehensive overview of the current landscape of pharmaceutical interventions for MAFLD and MASH, shedding light on the potential of newer drugs especially diabetic medications and the importance of ongoing research in this field.

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.

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.

Exploration and Development of PPAR Modulators in Health and Disease: An Update of Clinical Evidence

Peroxisome proliferator-activated receptors (PPARs) are nuclear receptors that govern the expression of genes responsible for energy metabolism, cellular development, and differentiation. Their crucial biological roles dictate the significance of PPAR-targeting synthetic ligands in medical research and drug discovery. Clinical implications of PPAR agonists span across a wide range of health conditions, including metabolic diseases, chronic inflammatory diseases, infections, autoimmune diseases, neurological and psychiatric disorders, and malignancies. In this review we aim to consolidate existing clinical evidence of PPAR modulators, highlighting their clinical prospects and challenges. Findings from clinical trials revealed that different agonists of the same PPAR subtype could present different safety profiles and clinical outcomes in a disease-dependent manner. Pemafibrate, due to its high selectivity, is likely to replace other PPARα agonists for dyslipidemia and cardiovascular diseases. PPARγ agonist pioglitazone showed tremendous promises in many non-metabolic disorders like chronic kidney disease, depression, inflammation, and autoimmune diseases. The clinical niche of PPARβ/δ agonists is less well-explored. Interestingly, dual- or pan-PPAR agonists, namely chiglitazar, saroglitazar, elafibranor, and lanifibranor, are gaining momentum with their optimistic outcomes in many diseases including type 2 diabetes, dyslipidemia, non-alcoholic fatty liver disease, and primary biliary cholangitis. Notably, the preclinical and clinical development for PPAR antagonists remains unacceptably deficient. We anticipate the future design of better PPAR modulators with minimal off-target effects, high selectivity, superior bioavailability, and pharmacokinetics. This will open new possibilities for PPAR ligands in medicine.

Treatment options for alcoholic and non-alcoholic fatty liver disease: A review

Alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD) are serious health problems worldwide. These two diseases have similar pathological spectra, ranging from simple steatosis to hepatitis to cirrhosis and hepatocellular carcinoma. Although most people with excessive alcohol or calorie intake display abnormal fat accumulation in the liver (simple steatosis), a small percentage develops progressive liver disease. Despite extensive research on understanding the pathophysiology of both these diseases there are still no targeted therapies available. The treatment for ALD remains as it was 50 years ago: abstinence, nutritional support and corticosteroids (or pentoxifylline as an alternative if steroids are contraindicated). As for NAFLD, the treatment modality is mainly directed toward weight loss and co-morbidity management. Therefore, new pathophysiology directed therapies are urgently needed. However, the involvement of several inter-related pathways in the pathogenesis of these diseases suggests that a single therapeutic agent is unlikely to be an effective treatment strategy. Hence, a combination therapy towards multiple targets would eventually be required. In this review, we delineate the treatment options in ALD and NAFLD, including various new targeted therapies that are currently under investigation. We hope that soon we will be having an effective multi-therapeutic regimen for each disease.

Non-alcoholic fatty liver disease: An update with special focus on the role of gut microbiota

Non-alcoholic fatty liver disease (NAFLD) is a significant global health burden in children, adolescents and adults with substantial rise in prevalence over the last decades. Accumulating data from manifold studies support the idea of NAFLD as a hepatic manifestation of metabolic syndrome, being rather a systemic metabolic disease than a liver confined pathology. Emerging data support that the gut microbiome represents a significant environmental factor contributing to NAFLD development and progression. Apart from other regimens, probiotics may have a positive role in the management of NAFLD through a plethora of possible mechanisms. The current review focuses on the NAFLD multifactorial pathogenesis, including mainly the role of intestinal microbiome and all relevant issues are raised. Furthermore, the clinical manifestations and appropriate diagnostic approach of the disease are discussed, with all possible therapeutic measures that can be taken, also including the potential beneficial effect of probiotics.

Combination with Red ginseng and Polygoni Multiflori ameliorates highfructose diet induced metabolic syndrome

BACKGROUND

Metabolic syndrome such as dyslipidemia, hypertension, obesity, impaired glucose tolerance and fatty liver, can be caused by modification of diet by means of overconsumption of high fructose diet. This study was designed to investigate whether combination with Red ginseng and Polygoni Multiflori Radix (RGPM), widely used traditional herbal medicine, ameliorates on highfructose (HF) diet-induced metabolic syndrome.

METHODS

SD rats were fed the 60% HF diet with/without rosiglitazone, and RGPM 100, 300 mg/kg/day, respectively. All groups received regular diet or HF diet, respectively, for 8 weeks. The last three groups treatment of rosiglitazone and RPGM orally for a period of 6 weeks.

RESULTS

Chronic treatment with RGPM significantly decreased body weight, fat weight and adipocyte size. RGPM significantly prevented the development of the metabolic disturbances such as hypertension, hyperlipidemia and impaired glucose tolerance. RGPM also led to increase in high density lipoprotein level in the HF group. RGPM suppressed high-fructose diet induced vascular inflammation marker expression such as adhesion molecules and ET-1 in aorta as well as increasing of C-reactive protein (CRP) levels in plasma. Similarly, RGPM attenuated hepatic lipid accumulation by inhibition of monocyte chemoattractant protein-1 (MCP-1) expression.

CONCLUSION

An administration of RGPM may be a beneficial therapy for the treatment of metabolic syndrome through the improvement of hypertension, obesity, hyperlipidemia, vascular inflammation and insulin resistance.

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

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

CONCLUSIONS

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

Endoplasmic reticulum stress and Oxidative stress in the pathogenesis of Non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the hepatic manifestation of metabolic syndrome. The underlying causes of the disease progression in NAFLD are unclear. Recent evidences suggest endoplasmic reticulum stress in the development of lipid droplets (steatosis) and subsequent generation of reactive oxygen species (ROS) in the progression to non-alcoholic steatohepatitis (NASH). The signalling pathway activated by disruption of endoplasmic reticulum (ER) homoeostasis, called as unfolded protein response, is linked with membrane biosynthesis, insulin action, inflammation and apoptosis. ROS are important mediators of inflammation. Protein folding in ER is linked to ROS. Therefore understanding the basic mechanisms that lead to ER stress and ROS in NAFLD have become the topics of immense interest. The present review focuses on the role of ER stress and ROS in the pathogenesis of NAFLD. We also highlight the cross talk between ER stress and oxidative stress which suggest and encourage the development of therapeutics for NAFLD. Further we have reviewed various strategies used for the management of NAFLD/NASH and limitations of such strategies. Our review therefore highlights the need for newer strategies with regards to ER stress and oxidative stress.

Non-alcoholic fatty liver disease in 2015

There is worldwide epidemic of non-alcoholic fatty liver disease (NAFLD). NAFLD is a clinical entity related to metabolic syndrome. Majority of the patients are obese but the disease can affect non-obese individuals as well. Metabolic factors and genetics play important roles in the pathogenesis of this disorder. The spectrum of disorders included in NAFLD are benign macrovesicular hepatic steatosis, non-alcoholic steatohepatitis, hepatic fibrosis, cirrhosis of liver and hepatocellular carcinoma. Although the disease remains asymptomatic most of the time, it can slowly progress to end stage liver disease. It will be the most common indication of liver transplantation in the future. It is diagnosed by abnormal liver chemistry, imaging studies and liver biopsy. As there are risks of potential complications during liver biopsy, many patients do not opt for liver biopsy. There are some noninvasive scoring systems to find out whether patients have advanced hepatic fibrosis. At the present time, there are limited treatment options which include lifestyle modification to loose weight, vitamin E and thioglitazones. Different therapeutic agents are being investigated for optimal management of this entity. There are some studies done on incretin based therapies in patients with NAFLD. Other potential agents will be silent information regulator protein Sirtuin and antifibrotic monoclonal antibody Simtuzumab against lysyl oxidase like molecule 2. But they are still in the investigational phase.

Non-alcoholic fatty liver disease in 2015

There is worldwide epidemic of non-alcoholic fatty liver disease (NAFLD). NAFLD is a clinical entity related to metabolic syndrome. Majority of the patients are obese but the disease can affect non-obese individuals as well. Metabolic factors and genetics play important roles in the pathogenesis of this disorder. The spectrum of disorders included in NAFLD are benign macrovesicular hepatic steatosis, non-alcoholic steatohepatitis, hepatic fibrosis, cirrhosis of liver and hepatocellular carcinoma. Although the disease remains asymptomatic most of the time, it can slowly progress to end stage liver disease. It will be the most common indication of liver transplantation in the future. It is diagnosed by abnormal liver chemistry, imaging studies and liver biopsy. As there are risks of potential complications during liver biopsy, many patients do not opt for liver biopsy. There are some noninvasive scoring systems to find out whether patients have advanced hepatic fibrosis. At the present time, there are limited treatment options which include lifestyle modification to loose weight, vitamin E and thioglitazones. Different therapeutic agents are being investigated for optimal management of this entity. There are some studies done on incretin based therapies in patients with NAFLD. Other potential agents will be silent information regulator protein Sirtuin and antifibrotic monoclonal antibody Simtuzumab against lysyl oxidase like molecule 2. But they are still in the investigational phase.

Non-alcoholic fatty liver disease: What has changed in the treatment since the beginning?

Non-alcoholic fatty liver disease (NAFLD) is an umbrella term to describe the entire spectrum of this common liver disease. In patients with NAFLD, especially those with non-alcoholic steatohepatitis (NASH), most often have one or more components of the metabolic syndrome, but this is not universal. Although most patients with NAFLD share many clinical features, only a subset of patients develops significant liver inflammation and progressive fibrosis. On the other hand, not all patients with NASH exhibit insulin resistance. NASH can be seen in patients who are lean and have no identifiable risk factors. Many clinical studies have tried numerous drugs and alternative medicine, however, investigators have failed to identify a safe and effective therapy for patients with NASH. As summarized, the heterogeneity of pathogenic pathways in individual patients with NASH may warrant the development of an individualized treatment according to the underlying pathogenic pathway. The differentiation of pathogenetic targets may require the development of diagnostic and prognostic biomarkers, and the identification of genetic susceptibilities. At present, evidence-based medicine provides only a few options including life-style modifications targeting weight loss, pioglitazone and vitamin E in non-diabetic patients with biopsy-proven NASH.

The therapy of insulin resistance in other diseases besides type 2 diabetes

Insulin resistance is a clinical condition shared by many diseases besides type 2 diabetes (T2DM) such as obesity, polycystic ovary syndrome (PCOS) and non-alcoholic fatty liver disease (NAFLD). Experimental evidence, produced over the years, suggests that metformin has many benefits in the treatment of these diseases. Metformin is a first-line drug in the treatment of overweight and obese type 2 diabetic patients, offering a selective pathophysiological approach by its effect on insulin resistance. Moreover, a number of studies have established the favorable effect of metformin on body weight, not only when evaluating BMI, but also if body mass composition is considered, through the reduction of fat mass. In addition, it reduces insulin resistance, hyperinsulinemia, lipid parameters, arterial hypertension and endothelial dysfunction. In particular, a new formulation of metformin extended-release (ER) is now available with different formulation in different countries. Metformin ER delivers the active drug through hydrated polymers which expand safe uptake of fluid, prolonging gastric transit and delaying drug absorption in the upper gastrointestinal tract. In addition, Metformin ER causes a small, but statistically significant decrease in BMI, when added to a lifestyle intervention program in obese adolescents. Because of the suggested benefits for the treatment of insulin resistance in many clinical conditions, besides type 2 diabetes, the prospective exists that more indications for metformin treatment are becoming a reality.

Nonalcoholic Fatty liver: a possible new target for type 2 diabetes prevention and treatment

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disorder worldwide. Several lines of evidence have indicated a pathogenic role of insulin resistance, and a strong association with type 2 diabetes (T2MD) and metabolic syndrome. Importantly, NAFLD appears to enhance the risk for T2MD, as well as worsen glycemic control and cardiovascular disease in diabetic patients. In turn, T2MD may promote NAFLD progression. The opportunity to take into account NAFLD in T2MD prevention and care has stimulated several clinical studies in which antidiabetic drugs, such as metformin, thiazolidinediones, GLP-1 analogues and DPP-4 inhibitors have been evaluated in NAFLD patients. In this review, we provide an overview of preclinical and clinical evidences on the possible efficacy of antidiabetic drugs in NAFLD treatment. Overall, available data suggest that metformin has beneficial effects on body weight reduction and metabolic parameters, with uncertain effects on liver histology, while pioglitazone may improve liver histology. Few data, mostly preclinical, are available on DPP4 inhibitors and GLP-1 analogues. The heterogeneity of these studies and the small number of patients do not allow for firm conclusions about treatment guidelines, and further randomized, controlled studies are needed.

Metformin in non-alcoholic fatty liver disease: A systematic review and meta-analysis

Non-alcoholic fatty liver disease (NAFLD) related to insulin resistance (IR) is a growing global health concern. Recent studies have indicated that metformin could improve IR and may be beneficial in the treatment of NAFLD. This study aimed to assess the beneficial or harmful effects of metformin in NAFLD. We searched Medline and four other databases during April 2012. Selection criteria were randomized clinical trials comparing metformin with placebo or other interventions for treating NAFLD patients. The primary outcome was histological response. The secondary outcomes included alanine aminotransferase (ALT), aspartate aminotransferase (AST), homeostasis model assessment of IR (HOMA-IR), body mass index (BMI) and adverse events. Dichotomous data were reported as odds ratio (OR), while continuous data were calculated as the mean difference (MD), both with 95% confidence intervals (CI). Random and fixed effects meta-analyses were performed. Nine studies were included, involving 417 participants, and conducted for a time period ranging from 4 to 12 months. In the treated participants, improvements were observed in ALT (MD, -8.12 U/l; P=0.03), AST (MD, -4.52 U/l; P=0.04), HOMA-IR (MD, -0.61; P=0.005) and BMI (MD, -0.82 kg/m²; P=0.04), but not in histological response: steatosis (P=0.66), inflammation (P=0.91), hepatocellular ballooning (P= 0.25) and fibrosis (P= 0.90). Sub-analysis of non-alcoholic fatty steatohepatitis showed that metformin failed to improve any pooled outcome. Adverse events were poorly reported. Current information indicates that metformin improves liver function, HOMA-IR and BMI to some extent, but not histological response in NAFLD patients. This finding could serve as a stimulus for future studies investigating issues such as dose-responsiveness, safety and patient tolerance to metformin therapy.

Metformin in non-alcoholic fatty liver disease: A systematic review and meta-analysis

Non-alcoholic fatty liver disease (NAFLD) related to insulin resistance (IR) is a growing global health concern. Recent studies have indicated that metformin could improve IR and may be beneficial in the treatment of NAFLD. This study aimed to assess the beneficial or harmful effects of metformin in NAFLD. We searched Medline and four other databases during April 2012. Selection criteria were randomized clinical trials comparing metformin with placebo or other interventions for treating NAFLD patients. The primary outcome was histological response. The secondary outcomes included alanine aminotransferase (ALT), aspartate aminotransferase (AST), homeostasis model assessment of IR (HOMA-IR), body mass index (BMI) and adverse events. Dichotomous data were reported as odds ratio (OR), while continuous data were calculated as the mean difference (MD), both with 95% confidence intervals (CI). Random and fixed effects meta-analyses were performed. Nine studies were included, involving 417 participants, and conducted for a time period ranging from 4 to 12 months. In the treated participants, improvements were observed in ALT (MD, -8.12 U/l; P=0.03), AST (MD, -4.52 U/l; P=0.04), HOMA-IR (MD, -0.61; P=0.005) and BMI (MD, -0.82 kg/m²; P=0.04), but not in histological response: steatosis (P=0.66), inflammation (P=0.91), hepatocellular ballooning (P= 0.25) and fibrosis (P= 0.90). Sub-analysis of non-alcoholic fatty steatohepatitis showed that metformin failed to improve any pooled outcome. Adverse events were poorly reported. Current information indicates that metformin improves liver function, HOMA-IR and BMI to some extent, but not histological response in NAFLD patients. This finding could serve as a stimulus for future studies investigating issues such as dose-responsiveness, safety and patient tolerance to metformin therapy.

Meta-analysis: pioglitazone improves liver histology and fibrosis in patients with non-alcoholic steatohepatitis

BACKGROUND

Thiazolidinediones (TZDs) have been used in the treatment of non-alcoholic steatohepatitis (NASH). However, the magnitude of treatment response associated with TZDs in improving liver histology in NASH has not been quantified systematically.

AIM

To conduct a meta-analysis of randomised, placebo-controlled clinical trials (RPCTs) using pioglitazone and rosiglitazone in the treatment of NASH.

METHODS

Pubmed/MEDLINE and Cochrane Central Register of Controlled Trials 2010 were searched until September 2010 and four RPCTs were identified. Peto odds ratios (ORs) and their respective 95% confidence intervals (CIs) were used to assess the efficacy of TZDs in improving liver histological parameters.

RESULTS

Four good quality RPCTs derived from three continents were included. The meta-analysis showed that TZDs (n = 169) were significantly better than placebo (n = 165) in improving ballooning degeneration, lobular inflammation and steatosis with combined ORs of 2.11 (95% CI, 1.33-3.36), 2.58 (95% CI, 1.68-3.97) and 3.39 (95% CI, 2.19-5.25) respectively. The improvement in combined necroinflammation with TZD (n = 58) vs. placebo (n = 52) was also statistically significant (combined OR 6.52[95% CI, 3.03-14.06]), but improvement in fibrosis was not. When pioglitazone (n = 137) was analysed alone, the improvement in fibrosis with pioglitazone (n = 137) vs. placebo (n = 134) (combined OR 1.68 [95% CI, 1.02-2.77]) was statistically significant. The total body fat slightly decreased in the control, while it markedly and highly significantly increased with TZD treatment.

CONCLUSIONS

Thiazolidinediones significantly improve ballooning degeneration, lobular inflammation, steatosis and combined necroinflammation in patients with NASH. Pioglitazone may improve fibrosis. Larger randomised, placebo-controlled clinical trials are needed to examine the efficacy of thiazolidinediones in improving NASH fibrosis.

Physical activity recommendations, exercise intensity, and histological severity of nonalcoholic fatty liver disease

OBJECTIVES

Factors that determine disease severity in nonalcoholic fatty liver disease (NAFLD) are unclear, but exercise is a recommended treatment. We evaluated the association between physical activity intensity and histological severity of NAFLD.

METHODS

We conducted a retrospective analysis of adults with biopsy-proven NAFLD enrolled in the NASH CRN (Nonalcoholic Steatohepatitis Clinical Research Network). Using self-reported time spent in physical activity, we classified participants as inactive or as meeting the US guidelines for either moderate or vigorous exercise. Histology was reviewed by a central pathology committee. Frequency and odds of steatohepatitis (NASH) and advanced fibrosis were compared between subjects who either met or did not meet exercise recommendations, and by the total amount of exercise per week.

RESULTS

A total of 813 adults (males=302, females=511) with NAFLD were included, with a mean age of 48 years. Neither moderate-intensity exercise nor total exercise per week was associated with NASH or stage of fibrosis. Meeting vigorous recommendations was associated with a decreased adjusted odds of having NASH (odds ratio (OR): 0.65 (0.43-0.98)). Doubling the recommended time spent in vigorous exercise, as is suggested for achieving additional health benefits, was associated with a decreased adjusted odds of advanced fibrosis (OR: 0.53 (0.29-0.97)).

CONCLUSIONS

These data support an association of vigorous but not moderate or total exercise with the severity of NAFLD. Optimal doses of exercise by duration and intensity for the prevention or treatment of NASH have not been established; however, intensity may be more important than duration or total volume.

Hepatic effects of rosiglitazone in rats with the metabolic syndrome

Rats given fructose-enriched diet develop many characteristics of the human metabolic syndrome and non-alcoholic fatty liver disease. In this study, we characterized the hepatic effects of rosiglitazone in fructose-enriched diet rats. Rats were randomly divided into three groups. One group was maintained on standard rat chow diet for 6 weeks, whereas the other two groups were given fructose-enriched diet for 6 weeks. Four weeks after the initiation of fructose-enriched diet, one of the fructose-enriched diet groups was also given rosiglitazone (10 mg/kg/day) for an additional 2 weeks. Rosiglitazone administration to the fructose-enriched diet rats was associated with decreases in the following parameters: blood pressure (-17%), plasma triglycerides (-62%), hepatic total lipids (-19%), hepatic triglycerides (-61%), hepatic malondialdehyde (-88%), glutathione reductase activity (-84%). An increase in adiponectin plasma levels (+329%), hepatic phospholipids (+46%), hepatic alpha-tocopherol concentrations (+24%) and hepatic paraoxonase activity (+68%) was observed. Rosiglitazone caused a decrease in hepatic macrovesicular steatosis score but no change in hepatic fibrosis. Administration of rosiglitazone, to rats with the metabolic syndrome has limited hepatic favourable effects: it improves hepatic lipid metabolism, decreases macrovesicular steatosis and improves some of the hepatic oxidative-anti-oxidative milieu but has no effect on hepatic fibrosis.

Insulin sensitizers in nonalcoholic fatty liver disease and steatohepatitis: Current status

Nonalcoholic fatty liver disease (NAFLD), first described in 1980, is now recognized as one of the most common causes of elevated liver enzymes and chronic liver disease in Western countries. The incidence of NAFLD in both adults and children is rising, in conjunction with the burgeoning epidemics of obesity and type 2 diabetes mellitus. NAFLD often coexists with other sequelae of the metabolic syndrome: central obesity, type 2 diabetes, hypertension, and hyperlipidemia. NAFLD encompasses a spectrum of pathologic liver diseases ranging from simple hepatic steatosis to a predominant lobular necro-inflammation, with or without centrilobular fibrosis (called nonalcoholic steatohepatitis or NASH). NASH can progress to cirrhosis, decompensated liver disease, and hepatocellular carcinoma. Though the natural history of NASH is still not clearly defined, it has been observed to progress to cirrhosis in 15%-220% of those affected. Insulin resistance is nearly universal in NASH and is thought to play an important role in its pathogenesis leading to dysregulated lipid metabolism. The prevalence of insulin resistance is reported in the general population to be approaching 45%, suggesting that NAFLD and NASH will contin nue to be an important public health concern. To date, NASH has proven to be a difficult disease to treat. Front-line therapy with lifestyle modifications resulting in weight loss through decreased caloric intake and moderate exercise is generally believed to be beneficial in patients with NASH, but is often difficult to maintain long term. Given that insulin resistance plays a dominant role in the pathogenesis, many studies have examined the use of insulin sensitizers: the biguanides (metformin), thiazolidinediones (pioglitazone, troglitazone, and rosiglitazone), glucagon-like peptide-1-receptor agonists, or incretins (exenatide)in NASH. This review will provide an overview of insulin resistance in NAFLD and provide a detailed summary on the clinical data regarding the use of insulin sensitizers in NASH.

The effect of metformin on leptin in obese patients with type 2 diabetes mellitus and nonalcoholic fatty liver disease

Insulin resistance is a major feature of type 2 diabetes mellitus, obesity and nonalcoholic fatty liver disease (NAFLD). Several studies pointed out the possible role of increased leptin in NAFLD in humans. The aim of this study is to determine the effect of metformin on plasma leptin levels in obese patients with type 2 diabetes mellitus and NAFLD compared with lifestyle interventions. Thirty-four obese patients with newly diagnosed type 2 diabetes mellitus were prospectively followed for 6 months. All patients had ultrasonographic evidence of NAFLD at baseline. The patients were randomized into two groups: group 1 (n = 15) followed lifestyle changes only and group 2 (n = 19) received metformin (1,700 mg/day). At the end of treatment, BMI, WHR, HbA1c, fasting glucose, leptin, HOMA-IR, alanine aminotransferase values decreased in both groups. No significant difference in the end-points was observed between two groups. Only in group 2, LDL decreased and HDL increased significantly. Liver echogenity decreased significantly at the end of study in both groups. The percentage of patients who no longer had evidence of NAFLD was not significantly different between the groups (20% of patients on lifestyle intervention vs. 16% of patients on metformin). The data demonstrate that, metformin and lifestyle interventions equally affected the plasma leptin levels, BMI and degree of NAFLD in obese patients with type 2 diabetes mellitus. In addition, the effects of metformin on the variables were not found to be mediated by leptin.

Current treatment of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of liver disease in Western World and frequently associated with insulin resistance and overweight and occurs often with type 2 diabetes. Interestingly, NAFLD is not only regarded as a hepatic component of the metabolic syndrome but also as an independent risk factor and a marker for increase in cardiovascular disease (CVD). Significantly, NAFLD is associated with an increased risk of all-cause mortality and predicts future CVD events independent of age, sex, LDL-cholesterol and features of metabolic syndrome. Although there was initial concern about drug toxicity with NAFLD, increasing evidence suggests that commonly used drugs such as metformin and statins do not cause harm and the thiazolidinediones (TZDs) may even confer a therapeutic benefit in NAFLD. Interestingly, medical and surgical treatments of obesity show potential benefit in treating NAFLD. In this review, we have focused on the safety and therapeutic impact of TZDs, statins, metformins and obesity medications in NAFLD. The potential benefit of bariatric surgery and the role of weight loss per se in treating NAFLD are also discussed.

Treatment options for nonalcoholic Fatty liver disease

Nonalcoholic fatty liver disease comprises a range of disorders from steatosis and steatohepatitis through to cirrhosis. Nonalcoholic steatohepatitis can progress to cirrhosis and liver-related death. Therefore, managing this common disorder is becoming an important public health issue. Lifestyle measures are commonly suggested but robust data are lacking. Trials with antioxidants (vitamin E, betaine) as well as cytoprotectants (ursodeoxycholic acid) have been disappointing. While data for insulin sensitizers such as metformin are less conclusive, thiazolidinediones appear promising. However, not all patients respond to thiazolidinediones. Moreover, issues related to weight gain, cardiovascular risk need to be addressed. The use of endocannabinoid antagonists and insulin secretagogues are novel strategies to combat this disorder.

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.

Review article: diagnosis and treatment of non-alcoholic fatty liver disease

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is an increasingly prevalent condition affecting adults and children, leading to significant morbidity. It is often associated with the metabolic syndrome, although multiple pathogenetic mechanisms have been suggested. In the coming decades, it promises to be the leading cause of liver disease in industrial countries.

AIM

To provide a comprehensive, updated review of diagnosis and management of NAFLD and to appraise the evolution of new modalities in these areas.

METHODS

An Ovid MEDLINE search was performed to identify pertinent original research and review articles. Selected references in these articles were also evaluated.

RESULTS

The diagnosis of hepatic steatosis and steatohepatitis or non-alcoholic steatohepatitis (NASH) is not yet possible without liver biopsy. This is impractical given the large numbers affected by the condition. Current therapy has focused on improving insulin resistance and mediators of inflammation, factors probably associated with disease progression.

CONCLUSIONS

There are no proven non-invasive diagnostic modalities to distinguish NAFLD and NASH, but new biomarker panels are approximating the liver biopsy in accuracy. Therapeutic targets of drug development are in early stages, but a multifaceted approach will probably yield several treatment options in the years to come.

Liver biopsy in a district general hospital: Changes over two decades

AIM: To study liver biopsy practice over two decades in a district general hospital in the United Kingdom.

METHODS: We identified all patients who had at least one liver biopsy between 1986 and 2006 from the databases of the radiology and gastroenterology departments. Subjects with incomplete clinical data were excluded from the study.

RESULTS: A total of 103 liver biopsies were performed. Clinical data was available for 88 patients, with 95 biopsies. Between 1986 and 1996, 18 (95%) out of the 19 liver biopsies performed were blind and 6 (33%) were for primary biliary cirrhosis. Between 1996 and 2006, 14 (18%) out of 76 biopsies were blind; and the indications were abnormal liver tests (33%), hepatitis C (12%) and targeted-biopsies (11%). Liver biopsies were unhelpful in 5 (5%) subjects. Pain was the most common complication of liver biopsy (5%). No biopsy-related mortality was reported. There was a trend towards more technical failures and complications with the blind biopsy technique.

CONCLUSION: Liver biopsies performed in small district hospitals are safe and useful for diagnostic and staging purposes. Abnormal liver tests, non-alcoholic fatty liver disease and targeted biopsies are increasingly common indications. Ultrasound-guided liver biopsies are now the preferred method and are associated with fewer complications.