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

Treatment of nonalcoholic steatohepatitis in adults: present and future

Nonalcoholic steatohepatitis has become one of the most common liver-related health problems. This condition has been linked to an unhealthy diet and weight gain, but it can also be observed in nonobese people. The standard of care is represented by the lifestyle intervention. However, because this approach has several limitations, such as a lack of compliance, the use of many drugs has been proposed. The first-line pharmacological choices are vitamin E and pioglitazone, both showing a positive effect on transaminases, fat accumulation, and inflammation. Nevertheless, vitamin E has no proven effect on fibrosis and on long-term morbidity and mortality and pioglitazone has a negative impact on weight. Other drugs have been studied such as metformin, ursodeoxycholic acid, statins, pentoxiphylline, and orlistat with only partially positive results. Among the emerging treatments, telmisartan is particularly interesting as it seems to have an impact on insulin resistance, liver steatosis, inflammation, and fibrosis. However, the pathogenesis of steatohepatitis is highly complex and is determined by different parallel hits; indeed, the association of different drugs that act on various levels has been suggested. In conclusion, lifestyle intervention should be optimised and the associations of different drugs should be tested in large studies with long-term outcomes.

Altered morphine glucuronide and bile acid disposition in patients with nonalcoholic steatohepatitis

The functional impact of altered drug transport protein expression on the systemic pharmacokinetics of morphine, hepatically derived morphine glucuronide (morphine-3- and morphine-6-glucuronide), and fasting bile acids was evaluated in patients with biopsy-confirmed nonalcoholic steatohepatitis (NASH) compared to healthy subjects. The maximum concentration (Cmax ) and area under the concentration-time curve (AUC0-last ) of morphine glucuronide in serum were increased in NASH patients (343 vs. 225 nM and 58.8 vs. 37.2 µM*min, respectively; P ≤ 0.005); morphine pharmacokinetics did not differ between groups. Linear regression analyses detected an association of NASH severity with increased morphine glucuronide Cmax and AUC0-last (P < 0.001). Fasting serum glycocholate, taurocholate, and total bile acid concentrations were associated with NASH severity (P < 0.006). Increased hepatic basolateral efflux of morphine glucuronide and bile acids is consistent with altered hepatic transport protein expression in patients with NASH and may partially explain differences in efficacy and/or toxicity of some highly transported anionic drugs/metabolites in this patient population.

Renin-angiotensin system and fibrosis in non-alcoholic fatty liver disease

BACKGROUND & AIMS

Therapeutic options are limited for patients with non-alcoholic fatty liver disease (NAFLD). One promising approach is the attenuation of necroinflammation and fibrosis by inhibition of the renin-angiotensin system (RAS). We explored whether the risk of fibrosis was associated with the use of commonly used medications in NAFLD patients with hypertension. Specifically, we sought to determine the association between RAS blocking agents and severity of hepatic fibrosis in NAFLD patients with hypertension.

METHODS

Cross-sectional study where clinical information including demographics, anthropometry, medical history, concomitant medication use, biochemical and histological features were ascertained in 290 hypertensive patients with biopsy proven NAFLD followed at two hepatology outpatient clinics. Stage of hepatic fibrosis was compared in patients with and without RAS blocker use. Other risk factors for fibrosis were evaluated from the electronic medical records and patient follow-up.

RESULTS

Baseline characteristics of hypertensive patients treated with and without RAS blockers were similar except for less ballooning (1.02 vs. 1.31, P = 0.001) and lower fibrosis stage (1.63 vs. 2.16, P = 0.002) in patients on RAS blockers On multivariate analysis, advancing age (OR: 1.04; 95%CI: 1.01-1.06, P = 0.012) and presence of diabetes (OR: 2.55; 95%CI: 1.28-5.09, P = 0.008) had an independent positive association, while use of RAS blockers (OR: 0.37; 95%CI: 0.21-0.65, P = 0.001) and statins (OR: 0.52; 95%CI: 0.29-0.93, P = 0.029) had a negative association with advanced fibrosis.

CONCLUSION

Hypertensive patients with NAFLD on baseline RAS blockers had less advanced hepatic fibrosis suggesting a beneficial effect of RAS blockers in NAFLD.

Hepatic molecular effects of rosiglitazone in human non-alcoholic steatohepatitis suggest long-term pro-inflammatory damage

AIM

Glitazones are agonists of peroxisome proliferator-activated receptor-γ (PPAR-γ) and have been proposed for the treatment of non-alcoholic steatohepatitis (NASH). However, efficacy results are conflicting and hepatic molecular changes induced by glitazones are mostly unknown. The aim of this study was to analyze the hepatic inflammatory and fibrogenic molecular effects of rosiglitazone in NASH patients.

METHODS

Hepatic expression of PPAR-γ and several inflammatory/immune and fibrogenic genes were studied before and after a 12-month treatment with rosiglitazone or placebo in 25 patients with NASH from the Fatty Liver Improvement with Rosiglitazone Therapy (FLIRT) trial.

RESULTS

Treatment with rosiglitazone induced hepatic PPAR-γ expression but increased the expression of several pro-inflammatory genes such as SOCS3 and TLR4. There was a significant reduction in mRNA and protein levels of α-smooth muscle actin, compatible with previously documented antifibrotic actions of rosiglitazone on stellate cells. However, there was no change in type 1 collagen and transforming growth factor-β expression thus suggesting an offset of the antifibrogenic actions by long-term pro-inflammatory changes.

CONCLUSION

In NASH patients, hepatic PPAR-γ induction by rosiglitazone was associated with increased hepatic expression of pro-inflammatory genes which may explain the lack of long-term histological benefit shown in human studies with this drug. It is unclear whether these results are a class effect of PPAR-γ agonists or a specific effect of rosiglitazone.

Nonalcoholic fatty liver disease: A comprehensive review of a growing epidemic

Nonalcoholic fatty liver disease (NAFLD) is quickly becoming one of the most prominent causes of liver disease worldwide. The increasing incidence of NAFLD is tied to the obesity epidemic and the subsequent metabolic derangements brought along with it. Current efforts to elucidate the mechanism and causes of the disease have answered some questions, but much remains unknown about NAFLD. The aim of this article is to discuss the current knowledge regarding the pathogenesis of the disease, as well as the current and future diagnostic, preventative, and therapeutic options available to clinicians for the management of NAFLD.

Utility and appropriateness of the fatty liver inhibition of progression (FLIP) algorithm and steatosis, activity, and fibrosis (SAF) score in the evaluation of biopsies of nonalcoholic fatty liver disease

Biopsy is still the gold standard for the diagnosis of nonalcoholic steatohepatitis but the definition may vary among pathologists, a drawback especially in evaluation of biopsies for clinical trials. We previously developed a scoring system (steatosis, activity, fibrosis [SAF]) allowing the use of an algorithm (fatty liver inhibition of progression [FLIP]) for the classification of liver injury in morbid obesity. The aim of this study was to determine whether the use of the SAF score and FLIP algorithm can decrease interobserver variations among pathologists. In a first session, pathologists categorized 40 liver biopsies of patients with nonalcoholic fatty liver disease (NAFLD) according to their own experience. In a second reading session, each pathologist reclassified the same slides by using the FLIP algorithm and SAF score, blinded to their first evaluation. The experiment was repeated with two different groups of pathologists at varying levels of training in liver pathology. The percentage of biopsy interpretation concordant with reference evaluation increased from 77% to 97% in Group 1 and from 42% to 75% in Group 2 after the use of the SAF score and FLIP algorithm. The strength of concordance in classification increased in Group 1 from moderate (κ = 0.54) to substantial (κ = 0.66) and from fair (κ = 0.35) to substantial (κ = 0.61) in Group 2 with application of the algorithm. With regard to the SAF score, concordance was substantial in Group 1 for steatosis (κ = 0.61), activity (κ = 0.75), and almost perfect for fibrosis (κ = 0.83 after pooling 1a, 1b, and 1c together into a single score F1). Similar trends were observed in Group 2 (κ = 0.54 for S, κ = 0.68 for A, and κ = 0.72 for F).

CONCLUSION

The FLIP algorithm based on the SAF score should decrease interobserver variations among pathologists and are likely to be implemented in pathology practice.

Dipeptidyl peptidase-4 inhibitor attenuates hepatic fibrosis via suppression of activated hepatic stellate cell in rats

BACKGROUND

Dipeptidyl peptidase-4 inhibitor (DPP4-I) is clinically used as a new oral antidiabetic agent. Although DPP4 is reportedly associated with the progression of chronic liver diseases, the effect of DPP4-I on liver fibrosis development is still obscure. This study was designed to elucidate the effect of DPP4-I on liver fibrosis development in conjunction with the activated hepatic stellate cells (Ac-HSCs).

METHODS

The antifibrotic effect of DPP4-I was assessed in vivo and in vitro using porcine serum-induced experimental liver fibrosis model. DPP4-I, sitagliptin, at a clinically comparable low dose was administered by gavage daily.

RESULTS

DPP4-I significantly attenuated liver fibrosis development along with the suppression of hepatic transforming growth factor (TGF)-β1, total collagen, and tissue inhibitor of metalloproteinases-1 in a dose-dependent manner. These suppressive effects occurred almost concurrently with the attenuation of HSCs activation. Our in vitro studies showed that DPP4-I inhibited platelet-derived growth factor-BB-mediated proliferation of the Ac-HSCs as well as upregulation of TGF-β1 and α1(I)-procollagen at magnitudes similar to those of the in vivo studies. The inhibitory effects of DPP4-I against HSCs proliferation and fibrogenic gene expression are mediated through the inhibition of the phosphorylation of ERK1/2, p38 and Smad2/3, respectively.

CONCLUSIONS

DPP4-I markedly inhibits liver fibrosis development in rats via suppression of HSCs proliferation and collagen synthesis. These suppressive effects are associated with dephosphorylation of ERK1/2, p38 and Smad2/3 in the HSCs. Since DPP4-I is widely used in clinical practice, this drug may represent a potential new therapeutic strategy against liver fibrosis in the near future.

The role of medications for the management of patients with NAFLD

The article is intended to provide an overview of the strengths and limits of controlled trials of pharmacologic treatment of nonalcoholic fatty liver disease. No drug has so far been approved, although validated on histologic outcomes. Several new drugs are under scrutiny, acting with different mechanisms along the chain of events from fatty liver to fibrosis, cirrhosis, and hepatocellular carcinoma. The article investigates which drug, if any, should be preferred for a tailored intervention in individual patients, according to age, comorbidities, and disease severity, and if treatment should be continued lifelong, to prevent disease progression and long-term occurrence of cirrhosis.

Rosiglitazone and fenofibrate exacerbate liver steatosis in a mouse model of obesity and hyperlipidemia. A transcriptomic and metabolomic study

Peroxisome proliferator-activated receptors (PPAR) play an important role in the regulation of lipid and glucose metabolism, inflammatory, and vascular responses. We show the effect of treatment with two PPAR agonists, fenofibrate (FF) and rosiglitazone (RSG), on ob/ob and LDLR-double deficient mice, by combined gene-expression and metabolomic analyses. Male mice were daily treated for 12 weeks with RSG (10 mg·kg(1-)·day(-1) per os (p.o.), n = 8) and FF (50 mg·kg(1-)·day(-1) p.o., n = 8). Twelve untreated ob/ob and LDLR-double deficient mice were used as controls. To integrate the transcriptomic and metabolomic results, we designed a hierarchical algorithm, based on the average linkage method in clustering. Data were also interpreted with the Ingenuity Pathway Analysis program. FF and RSG treatments significantly increased the hepatic triglyceride content in the liver when compared with the control group, and the treatments induced an increase in the number and size of hepatic lipid droplets. Both drugs simultaneously activate pro-steatotic and antisteatotic metabolic pathways with a well-ordered result of aggravation of the hepatic lipid accumulation. The present study is a cautionary note not only to researchers on the basic mechanism of the action of PPAR activators but also to the use of these compounds in clinical practice.

Review of treatment options for nonalcoholic fatty liver disease

Although the future of NAFLD and NASH treatment has many promising agents, clinicians are currently faced with limited options with an emphasis on lifestyle modification. Figs. 1 and 2 summarize current practices for the diagnosis and treatment of NAFLD with the understanding that each patient's treatment must be customized to their comorbidities, exercise tolerance, and willingness to comply with therapy.

Pharmacological agents for nonalcoholic steatohepatitis

The rationale for specific pharmacologic therapy in nonalcoholic steatohepatitis (NASH) is determined by the potential for disease progression and the difficulties, in many patients, to successfully implement diet and lifestyle changes in the long term. Because they correct insulin resistance, insulin-sensitizing agents are attractive candidates for the treatment of NASH. However, two randomized studies have shown that vitamin E, despite having no effect on insulin sensitivity, achieves interesting histological and biochemical efficacy. This review provides an insight into the therapeutic efficacy and safety issues of different pharmacological agents tested in human NASH.

The effects of sulfonylureas plus metformin on lipids, blood pressure, and adverse events in type 2 diabetes: a meta-analysis of randomized controlled trials

To compare the effects of sulfonylureas and metformin versus metformin on lipid profiles, blood pressure, and adverse events. PubMed, EMbase, Chinese BioMedical Literature on disc, China National Knowledge Infrastructure, VIP database, and Wanfang database were searched for randomized controlled trials (RCTs), from inception to August 2012. Key outcomes were low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), total cholesterol (TC), blood pressure (BP), hemoglobin A1c (HbA1c), fasting insulin, and adverse events. Twenty RCTs were included in the analysis. Compared to metformin, the combination therapy of sulfonylureas and metformin slightly reduced HDL-C [-0.03, 95 % CI (-0.06, -0.01)] and HbA1c (-0.79, 95 % CI -0.96 to -0.63). However, it showed little effects on LDL-C, TG, TC, and BP. Glipizide plus metformin significantly increased fasting insulin [2.33, 95 % CI (1.94, 2.73)]. Hypoglycemia and nervous system side events were more frequent among patients treated with sulfonylureas plus metformin than metformin alone (RR = 6.79, 95 % CI 3.79-12.17; RR = 1.27, 95 % CI 1.03-1.57; respectively), but less in digestive symptoms (RR = 0.75, 95 % CI 0.67-0.84). Combination therapy with sulfonylureas and metformin may be more effective than metformin alone in improving HbA1c and reducing gastrointestinal reactions. But it had disadvantage of decreasing HDL-C, increasing the risk of hypoglycemia and nervous system side events.

Renal interactions in liver dysfunction and failure

PURPOSE OF REVIEW

This review will summarize the recent advances in our understanding of the relationship between liver and kidney function. It will outline the new concepts of the pathophysiology of renal dysfunction in chronic liver disease and examine novel renal biomarkers to detect acute kidney injury (AKI) in cirrhosis and following liver transplantation. We will further review new treatments for hepatorenal syndrome (HRS) and approaches to kidney dysfunction in liver transplantation recipients.

RECENT FINDINGS

Recent studies evaluated the effect of the renin-angiotensin system on hepatic fibrosis and the role of the gut in mediating AKI after hepatic ischemia reperfusion injury. Multiple studies have investigated novel biomarkers such as neutrophil gelatinase-associated lipocalin to predict AKI (and HRS) in cirrhosis and after liver transplantation. Furthermore, there were recent advances in the management of kidney dysfunction including management of HRS with vasopressin analogs and kidney-sparing immunosuppression after liver transplantation.

SUMMARY

Greater knowledge of the physiologic relationship between kidney and liver may open avenues for specific therapies of liver and kidney injury. Renal biomarkers may allow early diagnosis and targeted treatment of AKI, and improved management of kidney disease in the preliver and postliver transplantation setting will be crucial to improving long-term outcomes in these patients.

Current histological classification of NAFLD: strength and limitations

Nonalcoholic fatty liver disease (NAFLD) covers a spectrum of lesions ranging from pure steatosis without significant necroinflammatory injury (NAFL) to a complex pattern with lesions of hepatocyte injury and inflammation (nonalcoholic steatohepatitis, NASH) in the absence of significant alcohol intake. Because histopathological evaluation of liver biopsy samples remains central in NAFLD in the absence of a non-invasive test with enough accuracy, precise definition of each group is a key issue. When at least 5 % of hepatocytes display steatosis, patients can be qualified for NAFLD in an appropriate clinical context. When, in addition, lobular inflammation and liver cell clarification/ballooning are present, then the lesion can be qualified for NASH. Like for other chronic liver diseases, semiquantitative histological scoring has been proposed for NAFLD. These scoring systems are not useful in clinical practice, and each has some limitation. For comprehensive purposes, we suggest describing histopathological lesions in NAFLD using the SAF score, which assesses together and separately (1) the grade of steatosis (S, from S0 to S3) and (2) the grade of activity (A from A0 to A4 by adding the grades of ballooning and lobular inflammation, both from 0 to 2) and the stage of fibrosis (F from F0 to F4). Such a semiquantitative score could be used for assessing changes in paired biopsies spontaneously or during clinical trials. Finally, the SAF score could help to correctly describe borderline cases of fatty liver diseases that do not fulfill all of the diagnostic criteria of simple steatosis or steatohepatitis, but as for any scoring system, a comprehensive description of the different lesions in their appropriate context is still necessary.

Evolving therapies for liver fibrosis

Fibrosis is an intrinsic response to chronic injury, maintaining organ integrity when extensive necrosis or apoptosis occurs. With protracted damage, fibrosis can progress toward excessive scarring and organ failure, as in liver cirrhosis. To date, antifibrotic treatment of fibrosis represents an unconquered area for drug development, with enormous potential but also high risks. Preclinical research has yielded numerous targets for antifibrotic agents, some of which have entered early-phase clinical studies, but progress has been hampered due to the relative lack of sensitive and specific biomarkers to measure fibrosis progression or reversal. Here we focus on antifibrotic approaches for liver that address specific cell types and functional units that orchestrate fibrotic wound healing responses and have a sound preclinical database or antifibrotic activity in early clinical trials. We also touch upon relevant clinical study endpoints, optimal study design, and developments in fibrosis imaging and biomarkers.

Diabetes and nonalcoholic Fatty liver disease: a pathogenic duo

Recent data increasingly support a complex interplay between the metabolic condition diabetes mellitus and the pathologically defined nonalcoholic fatty liver disease (NAFLD). NAFLD predicts the development of type 2 diabetes and vice versa, and each condition may serve as a progression factor for the other. Although the association of diabetes and NAFLD is likely to be partly the result of a "common soil," it is also probable that diabetes interacts with NAFLD through specific pathogenic mechanisms. In particular, through interrelated metabolic pathways currently only partly understood, diabetes appears to accelerate the progression of NAFLD to nonalcoholic steatohepatitis, defined by the presence of necroinflammation, with varying degrees of liver fibrosis. In the research setting, obstacles that have made the identification of clinically significant NAFLD, and particularly nonalcoholic steatohepatitis, difficult are being addressed with the use of new imaging techniques combined with risk algorithms derived from peripheral blood profiling. These techniques are likely to be used in the diabetes population in the near future. This review examines the pathogenic links between NAFLD and diabetes by exploring the epidemiological evidence in humans and also through newer animal models. Emerging technology to help screen noninvasively for differing pathological forms of NAFLD and the potential role of preventive and therapeutic approaches for NAFLD in the setting of diabetes are also examined.

Nonalcoholic fatty liver disease: an emerging threat to obese and diabetic individuals

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease in the Western world and its incidence is increasing rapidly. NAFLD is a spectrum ranging from simple steatosis, which is relatively benign hepatically, to nonalcoholic steatohepatitis (NASH), which can progress to cirrhosis. Obesity, insulin resistance, type 2 diabetes mellitus, and dyslipidemia are the most important risk factors for NAFLD. Due to heavy enrichment with metabolic risk factors, individuals with NAFLD are at significantly higher risk for cardiovascular disease. Individuals with NAFLD have higher incidence of type 2 diabetes. The diagnosis of NAFLD requires imaging evidence of hepatic steatosis in the absence of competing etiologies including significant alcohol consumption. Liver biopsy remains the gold standard for diagnosing NASH and for determining prognosis. Weight loss remains a cornerstone of treatment. Weight loss of ∼5% is believed to improve steatosis, whereas ∼10% weight loss is necessary to improve steatohepatitis. A number of pharmacologic therapies have been investigated to treat NASH, and agents such as vitamin E and thiazolidinediones have shown promise in select patient subgroups.

Pharmacologic therapy for nonalcoholic fatty liver disease in adults

Nonalcoholic fatty liver disease (NAFLD) is characterized by the accumulation of triglycerides in hepatocytes in the absence of excessive alcohol intake, ranging in severity from simple steatosis to nonalcoholic steatohepatitis (NASH). Nonalcoholic steatohepatitis can ultimately progress to cirrhosis and hepatocellular carcinoma. NAFLD is associated with cardiometabolic risk factors and is the most common chronic liver disease among adults in the Western Hemisphere. Although simple steatosis is generally considered a self-limiting disease, evidence suggests an increased risk of cardiovascular disease, and, less conclusively, mortality, among individuals with NAFLD and/or NASH. The current standard of care for the treatment of patients with NAFLD focuses on lifestyle interventions, particularly diet and exercise. There is a lack of consensus regarding the most effective and appropriate pharmacologic therapy. A PubMed search was conducted using the medical subject heading terms "fatty liver" and "steatohepatitis." This review focuses on the current pharmacologic options available for treating adults with NAFLD and/or NASH. Continued investigation of drugs or combinations that improve NAFLD progression is crucial. Clinicians, particularly pharmacists, must take an active role in identification and appropriate selection of pharmacotherapy for NAFLD.

Peroxisome proliferator-activated receptor-γ as a therapeutic target for hepatic fibrosis: from bench to bedside

Hepatic fibrosis is a dynamic chronic liver disease occurring as a consequence of wound-healing responses to various hepatic injuries. This disorder is one of primary predictors for liver-associated morbidity and mortality worldwide. To date, no pharmacological agent has been approved for hepatic fibrosis or could be recommended for routine use in clinical context. Cellular and molecular understanding of hepatic fibrosis has revealed that peroxisome proliferator-activated receptor-γ (PPARγ), the functioning receptor for antidiabetic thiazolidinediones, plays a pivotal role in the pathobiology of hepatic stellate cells (HSCs), whose activation is the central event in the pathogenesis of hepatic fibrosis. Activation of PPARγ inhibits HSC collagen production and modulates HSC adipogenic phenotype at transcriptional and epigenetic levels. These molecular insights indicate PPARγ as a promising drug target for antifibrotic chemotherapy. Intensive animal studies have demonstrated that stimulation of PPARγ regulatory system through gene therapy approaches and PPARγ ligands has therapeutic promise for hepatic fibrosis induced by a variety of etiologies. At the same time, thiazolidinedione agents have been investigated for their clinical benefits primarily in patients with nonalcoholic steatohepatitis, a common metabolic liver disorder with high potential to progress to fibrosis and liver-related death. Although some studies have shown initial promise, none has established long-term efficacy in well-controlled randomized clinical trials. This comprehensive review covers the 10-year discoveries of the molecular basis for PPARγ regulation of HSC pathophysiology and then focuses on the animal investigations and clinical trials of various therapeutic modalities targeting PPARγ for hepatic fibrosis.

Nonalcoholic fatty liver disease and the renin-angiotensin system: Implications for treatment

Nonalcoholic fatty liver disease (NAFLD) is the commonest liver disease in Western countries. Treatment of NAFLD is currently based on lifestyle measures and no effective pharmacologic treatment is available so far. Emerging evidence, mainly from animal studies, suggests that the renin-angiotensin-aldosterone system may be of major importance in the pathogenesis of NAFLD and indicates that angiotensin-converting enzyme inhibitors (ACE-I) and angiotensin receptor blockers (ARBs) as a potentially useful therapeutic approach. However, data from human studies are limited and contradictory. In addition, there are few randomized controlled trials (RCTs) on the effects of ACE-I or ARB in patients with NAFLD and most data are from retrospective studies, pilot prospective studies and post hoc analyses of clinical trials. Accordingly, more and larger RCTs are needed to directly assess the effectiveness of ACE-I and ARBs in NAFLD.

Features, diagnosis, and treatment of nonalcoholic fatty liver disease

As the global incidence of obesity has increased, nonalcoholic fatty liver disease (NAFLD) has become a worldwide health concern. NAFLD occurs in children and adults of all ethnicities and includes isolated fatty liver and nonalcoholic steatohepatitis (NASH). Patients with NASH are at risk for developing cirrhosis, hepatic decompensation, and hepatocellular carcinoma and have increased all-cause mortality. NAFLD is associated with a variety of clinical conditions and is an independent risk factor for hepatocellular carcinoma. The pathogenesis of NAFLD and the specific steps that lead to NASH and advanced fibrosis are not fully understood, although researchers have found that a combination of environmental, genetic, and metabolic factors lead to advanced disease. There have been improvements in noninvasive radiographic methods to diagnose NAFLD, especially for advanced disease. However, liver biopsy is still the standard method of diagnosis for NASH. There are many challenges to treating patients with NASH, and no therapies have been approved by the U.S. Food and Drug Administration; multimodal approaches are being developed and becoming the standard of care. We review pathogenesis and treatment approaches for the West's largest liver-related public health concern.

Update on new aspects of the renin-angiotensin system in liver disease: clinical implications and new therapeutic options

The RAS (renin-angiotensin system) is now recognized as an important regulator of liver fibrosis and portal pressure. Liver injury stimulates the hepatic expression of components of the RAS, such as ACE (angiotensin-converting enzyme) and the AT(1) receptor [AngII (angiotensin II) type 1 receptor], which play an active role in promoting inflammation and deposition of extracellular matrix. In addition, the more recently recognized structural homologue of ACE, ACE2, is also up-regulated. ACE2 catalyses the conversion of AngII into Ang-(1-7) [angiotensin-(1-7)], and there is accumulating evidence that this 'alternative axis' of the RAS has anti-fibrotic, vasodilatory and anti-proliferative effects, thus counterbalancing the effects of AngII in the liver. The RAS is also emerging as an important contributor to the pathophysiology of portal hypertension in cirrhosis. Although the intrahepatic circulation in cirrhosis is hypercontractile in response to AngII, resulting in increased hepatic resistance, the splanchnic vasculature is hyporesponsive, promoting the development of the hyperdynamic circulation that characterizes portal hypertension. Both liver fibrosis and portal hypertension represent important therapeutic challenges for the clinician, and there is accumulating evidence that RAS blockade may be beneficial in these circumstances. The present review outlines new aspects of the RAS and explores its role in the pathogenesis and treatment of liver fibrosis and portal hypertension.

Management of Non-alcoholic Fatty Liver Disease and Steatohepatitis

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of abnormal liver enzymes and chronic liver disease in the US with expected rise in incidence paralleling the epidemic of obesity. A subset of patients with NAFLD have the progressive form of NAFLD that is termed non-alcoholic steatohepatitis (NASH), which is characterized by specific features on liver histology including hepatocellular ballooning degeneration, lobular inflammation, and zone-3 steatosis with or without peri-sinusoidal fibrosis. Non-alcoholic steatohepatitis can progress to cirrhosis and result in liver-related death. Insulin resistance is commonly seen in patients with NASH and often co-exists with other features of the metabolic syndrome including hypertension, hyperlipidemia, and obesity. Although weight loss through lifestyle modifications including dietary changes and increased physical exercise remains the backbone of management of NASH, it has proved challenging for patients to achieve and maintain weight loss goals. Thus, it is often necessary to couple lifestyle changes with another pharmacologic treatment for NASH. Insulin sensitizers including the biguanides (metformin), thiazolidinediones (pioglitazone and rosiglitazone), and glucagon-like peptide-1 receptor agonists (exenatide) are large groups of medications that have been studied for the treatment of NASH. Other agents with anti-inflammatory, anti-apoptotic, or anti-fibrotic properties which have been studied in NASH include vitamin E, pentoxifylline, betaine, and ursodeoxycholic acid. This review will provide a detailed summary on the clinical data behind the full spectrum of treatments that exist for NASH and suggest management recommendations.

Nonalcoholic fatty liver disease

As the hepatic manifestation of the metabolic syndrome, nonalcoholic fatty liver disease (NAFLD) has become the most common cause of asymptomatic liver enzyme elevations in Western nations. Although it is easy to diagnose NAFLD, a liver biopsy is currently required to diagnose nonalcoholic steatohepatitis (NASH). Patients with NASH are those at greatest risk of progression to cirrhosis and, thus, treatment efforts are targeted to these individuals. Although currently there are no FDA-approved treatments for NASH, a multidisciplinary approach that addresses comorbid conditions and promotes modest weight loss comprises the backbone of therapy.

Impact of current treatments on liver disease, glucose metabolism and cardiovascular risk in non-alcoholic fatty liver disease (NAFLD): a systematic review and meta-analysis of randomised trials

AIMS/HYPOTHESIS

Non-alcoholic fatty liver disease (NAFLD) encompasses a spectrum ranging from simple steatosis to non-alcoholic steatohepatitis (NASH): NAFLD causes an increased risk of cardiovascular disease, diabetes and liver-related complications (the latter confined to NASH). The effect of proposed treatments on liver disease, glucose metabolism and cardiovascular risk in NAFLD is unknown. We reviewed the evidence for the management of liver disease and cardio-metabolic risk in NAFLD.

METHODS

Publications through November 2011 were systematically reviewed by two authors. Outcomes evaluated though standard methods were: histological/radiological/biochemical features of NAFLD, variables of glucose metabolism and cardiovascular risk factors. Seventy-eight randomised trials were included (38 in NASH, 40 in NAFLD): 41% assessed post-treatment histology, 71% assessed glucose metabolism and 88% assessed cardiovascular risk factors. Lifestyle intervention, thiazolidinediones, metformin and antioxidants were most extensively evaluated.

RESULTS

Lifestyle-induced weight loss was safe and improved cardio-metabolic risk profile; a weight loss ≥7% improved histological disease activity, but was achieved by <50% patients. Statins and polyunsaturated fatty acids improved steatosis, but their effects on liver histology are unknown. Thiazolidinediones improved histological disease activity, glucose, lipid and inflammatory variables and delayed fibrosis progression. Pioglitazone also improved blood pressure. Weight gain (up to 4.8%) was common. Antioxidants yielded mixed histological results: vitamin E improved histological disease activity when administered for 2 years, but increased insulin resistance and plasma triacylglycerols.

CONCLUSIONS/INTERPRETATION

Weight loss is safe, and improves liver histology and cardio-metabolic profile. For patients not responding to lifestyle intervention, pioglitazone improves histological disease activity, slows fibrosis progression and extensively ameliorates cardio-metabolic endpoints. Further randomised controlled trials (RCTs) of adequate size and duration will assess long-term safety and efficacy of proposed treatments on clinical outcomes.

Role of obesity and lipotoxicity in the development of nonalcoholic steatohepatitis: pathophysiology and clinical implications

As obesity reaches epidemic proportions, nonalcoholic fatty liver disease (NAFLD) is becoming a frequent cause of patient referral to gastroenterologists. There is a close link between dysfunctional adipose tissue in NAFLD and common conditions such as metabolic syndrome, type 2 diabetes mellitus, and cardiovascular disease. This review focuses on the pathophysiology of interactions between adipose tissue and target organs in obesity and the resulting clinical implications for the management of nonalcoholic steatohepatitis. The release of fatty acids from dysfunctional and insulin-resistant adipocytes results in lipotoxicity, caused by the accumulation of triglyceride-derived toxic metabolites in ectopic tissues (liver, muscle, pancreatic beta cells) and subsequent activation of inflammatory pathways, cellular dysfunction, and lipoapoptosis. The cross talk between dysfunctional adipocytes and the liver involves multiple cell populations, including macrophages and other immune cells, that in concert promote the development of lipotoxic liver disease, a term that more accurately describes the pathophysiology of nonalcoholic steatohepatitis. At the clinical level, adipose tissue insulin resistance contributes to type 2 diabetes mellitus and cardiovascular disease. Treatments that rescue the liver from lipotoxicity by restoring adipose tissue insulin sensitivity (eg, significant weight loss, exercise, thiazolidinediones) or preventing activation of inflammatory pathways and oxidative stress (ie, vitamin E, thiazolidinediones) hold promise in the treatment of NAFLD, although their long-term safety and efficacy remain to be established. Better understanding of pathways that link dysregulated adipose tissue, metabolic dysfunction, and liver lipotoxicity will result in improvements in the clinical management of these challenging patients.

Nonalcoholic fatty liver disease: multimodal treatment options for a pathogenetically multiple-hit disease

Nonalcoholic fatty liver disease (NAFLD) has emerged as a significant public health problem. Besides the liver, NAFLD is also associated with increased cardiovascular and overall morbidity and mortality. NAFLD warrants intensive research, because no treatment has been established as yet. This may be partly attributed to the fact that the majority of the relative clinical trials have a monotherapeutic direction. However, the multifactorial pathogenesis of NAFLD may probably direct clinical trials to a combined therapeutic approach. The aim of this review is to provide a description of the multifactorial pathogenesis of NAFLD and type II diabetes mellitus-NAFLD interplay, and to summarize the therapeutic trials focusing on the combined NAFLD treatment, providing a link between the multiple-hit pathogenesis and the multimodal treatment of NAFLD patients. A diabetes-like therapeutic approach for NAFLD is finally proposed.