Effect of bariatric surgery on nonalcoholic fatty liver disease: systematic review and meta-analysis

Prevention and treatment of nonalcoholic fatty liver disease in patients with type 2 diabetes mellitus

Nonalcoholic fatty liver disease (NAFLD) is frequently seen in the type 2 diabetes mellitus (T2DM) population. Insulin resistance is the pathophysiologic bridge which links T2DM and NAFLD. Coexistence of both diseases indicates more severe diseases and higher risk of death. As a result, it is urgent to effectively control NAFLD in patients with T2DM. The advent of glucagon like peptide-1 (GLP-1) agonists and dipeptidyl peptidase-4 (DPP-4) inhibitors brings new hope for effectively managing NAFLD in T2DM patients. Bariatric surgery provides obese T2DM patients with a powerful means to treat NAFLD. The discovery of adipokines such as adiponectin and fibroblast growth factor 21 (FGF21) may point to a new research direction for NAFLD. In this paper, we present therapeutic options currently available for NAFLD in T2DM patients as well as the present research progress in NAFLD with T2DM, with regards to epidemiology and pathophysiologic links between them.

Cost-effectiveness of non-invasive methods for assessment and monitoring of liver fibrosis and cirrhosis in patients with chronic liver disease: systematic review and economic evaluation

BACKGROUND

Liver biopsy is the reference standard for diagnosing the extent of fibrosis in chronic liver disease; however, it is invasive, with the potential for serious complications. Alternatives to biopsy include non-invasive liver tests (NILTs); however, the cost-effectiveness of these needs to be established.

OBJECTIVE

To assess the diagnostic accuracy and cost-effectiveness of NILTs in patients with chronic liver disease.

DATA SOURCES

We searched various databases from 1998 to April 2012, recent conference proceedings and reference lists.

METHODS

We included studies that assessed the diagnostic accuracy of NILTs using liver biopsy as the reference standard. Diagnostic studies were assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. Meta-analysis was conducted using the bivariate random-effects model with correlation between sensitivity and specificity (whenever possible). Decision models were used to evaluate the cost-effectiveness of the NILTs. Expected costs were estimated using a NHS perspective and health outcomes were measured as quality-adjusted life-years (QALYs). Markov models were developed to estimate long-term costs and QALYs following testing, and antiviral treatment where indicated, for chronic hepatitis B (HBV) and chronic hepatitis C (HCV). NILTs were compared with each other, sequential testing strategies, biopsy and strategies including no testing. For alcoholic liver disease (ALD), we assessed the cost-effectiveness of NILTs in the context of potentially increasing abstinence from alcohol. Owing to a lack of data and treatments specifically for fibrosis in patients with non-alcoholic fatty liver disease (NAFLD), the analysis was limited to an incremental cost per correct diagnosis. An analysis of NILTs to identify patients with cirrhosis for increased monitoring was also conducted.

RESULTS

Given a cost-effectiveness threshold of £20,000 per QALY, treating everyone with HCV without prior testing was cost-effective with an incremental cost-effectiveness ratio (ICER) of £9204. This was robust in most sensitivity analyses but sensitive to the extent of treatment benefit for patients with mild fibrosis. For HBV [hepatitis B e antigen (HBeAg)-negative)] this strategy had an ICER of £28,137, which was cost-effective only if the upper bound of the standard UK cost-effectiveness threshold range (£30,000) is acceptable. For HBeAg-positive disease, two NILTs applied sequentially (hyaluronic acid and magnetic resonance elastography) were cost-effective at a £20,000 threshold (ICER: £19,612); however, the results were highly uncertain, with several test strategies having similar expected outcomes and costs. For patients with ALD, liver biopsy was the cost-effective strategy, with an ICER of £822.

LIMITATIONS

A substantial number of tests had only one study from which diagnostic accuracy was derived; therefore, there is a high risk of bias. Most NILTs did not have validated cut-offs for diagnosis of specific fibrosis stages. The findings of the ALD model were dependent on assuptions about abstinence rates assumptions and the modelling approach for NAFLD was hindered by the lack of evidence on clinically effective treatments.

CONCLUSIONS

Treating everyone without NILTs is cost-effective for patients with HCV, but only for HBeAg-negative if the higher cost-effectiveness threshold is appropriate. For HBeAg-positive, two NILTs applied sequentially were cost-effective but highly uncertain. Further evidence for treatment effectiveness is required for ALD and NAFLD.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42011001561.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Nutritional Modulation of Non-Alcoholic Fatty Liver Disease and Insulin Resistance

Non-alcoholic fatty liver disease (NAFLD) covers a spectrum of disorders ranging from simple steatosis (non-alcoholic fatty liver, NAFL) to non-alcoholic steatohepatitis (NASH) and cirrhosis. NAFL increases the risk of liver fibrosis. If the liver is fatty due to causes of insulin resistance such as obesity and physical inactivity, it overproduces glucose and triglycerides leading to hyperinsulinemia and a low high-density lipoprotein (HDL) cholesterol concentration. The latter features predispose to type 2 diabetes and cardiovascular disease (CVD). Understanding the impact of nutritional modulation of liver fat content and insulin resistance is therefore of interest for prevention and treatment of NAFLD. Hypocaloric, especially low carbohydrate ketogenic diets rapidly decrease liver fat content and associated metabolic abnormalities. However, any type of caloric restriction seems effective long-term. Isocaloric diets containing 16%-23% fat and 57%-65% carbohydrate lower liver fat compared to diets with 43%-55% fat and 27%-38% carbohydrate. Diets rich in saturated (SFA) as compared to monounsaturated (MUFA) or polyunsaturated (PUFA) fatty acids appear particularly harmful as they increase both liver fat and insulin resistance. Overfeeding either saturated fat or carbohydrate increases liver fat content. Vitamin E supplementation decreases liver fat content as well as fibrosis but has no effect on features of insulin resistance.

Non-Alcoholic Steatohepatitis (NASH): Risk Factors in Morbidly Obese Patients

The aim was to investigate the prevalence of non-alcoholic steatohepatitis (NASH) and risk factors for hepatic fibrosis in morbidly obese patients submitted to bariatric surgery. This retrospective study recruited all patients submitted to bariatric surgery from January 2007 to December 2012 at a reference attendance center of Southern Brazil. Clinical and biochemical data were studied as a function of the histological findings of liver biopsies done during the surgery. Steatosis was present in 226 (90.4%) and NASH in 176 (70.4%) cases. The diagnosis of cirrhosis was established in four cases (1.6%) and fibrosis in 108 (43.2%). Risk factors associated with NASH at multivariate analysis were alanine aminotransferase (ALT) >1.5 times the upper limit of normal (ULN); glucose ≥ 126 mg/dL and triglycerides ≥ 150 mg/dL. All patients with ALT ≥1.5 times the ULN had NASH. When the presence of fibrosis was analyzed, ALT > 1.5 times the ULN and triglycerides ≥ 150 mg/dL were risk factors, furthermore, there was an increase of 1% in the prevalence of fibrosis for each year of age increase. Not only steatosis, but NASH is a frequent finding in MO patients. In the present study, ALT ≥ 1.5 times the ULN identifies all patients with NASH, this finding needs to be further validated in other studies. Moreover, the presence of fibrosis was associated with ALT, triglycerides and age, identifying a subset of patients with more severe disease.

Nonalcoholic Fatty Liver Disease and Fibrosis in Youth Taking Psychotropic Medications: Literature Review, Case Reports, and Management

OBJECTIVE

Nonalcoholic fatty liver disease (NAFLD) has become a worldwide epidemic because of the greater prevalence of obesity. Despite implications for youth with severe mental disorders, little has been published in the psychiatric literature about this increasingly common medical comorbidity. The goals of this article are to: 1) provide an overview of the epidemiology and pathophysiology of NAFLD, including progression to nonalcoholic steatohepatitis (NASH); 2) describe two clinical cases illustrating difficulties faced in management; and 3) review screening recommendations, differential diagnosis, and monitoring and intervention approaches.

METHODS

A literature review was conducted, including guidelines and recommendations, with case presentations including case and control liver histology biopsy photographs.

RESULTS

NAFLD in childhood and adolescence, as a precursor to NASH, progresses to fibrosis in a small percentage of youth, leading to risk for early onset cirrhosis and the need for transplantation. The cases presented raise concern that youth with severe mental health disorders, already at greater risk for obesity and its sequelae, may be at higher risk for progression to NASH, potentially because of greater rates of weight gain on top of overweight or obese status, and to liver metabolism changes from psychotropic medications favoring fat deposition.

CONCLUSIONS

Patients with rapid weight gain into the overweight or obese categories, or who develop elevated liver transaminases that persist across 3-6 months, should be screened or referred for screening by their psychotropic-providing clinicians for early detection, diagnosis, and co-management by a pediatric gastroenterologist, to decrease risk of progression to NASH, which is reversible if early and sufficient lifestyle change results in significant weight loss. There is urgent need for controlled research on the relationships among weight gain, psychotropic medications, ultrasound and biopsy findings, and rates of progression to NAFLD and NASH in youth taking weight-gain-inducing psychotropic medications.

The Effect of Intraoperative N-Acetylcysteine on Hepatocellular Injury During Laparoscopic Bariatric Surgery. A Randomised Controlled Trial

BACKGROUND

The combination of pneumoperitoneum and intraoperative retraction of the left lobe of the liver leads to hepatocellular injury during laparoscopic gastric surgery. Fatty livers are more susceptible to ischaemic insults. This trial investigated whether the antioxidant N-acetylcysteine (NAC) reduced liver injury during laparoscopic sleeve gastrectomy (LSG).

METHODS

Patients undergoing LSG were randomised (single blinded) to receive intraoperative NAC infusion or standard anaesthetic treatment. Blood samples were taken before and after surgery (days 0 to 4). Primary endpoints included serum aminotransferases. Secondary measures were C-reactive protein, weight cell count (WCC), cytokines (interleukin 6 and 10) and cytokeratin-18 as markers of apoptosis. Intraoperative liver biopsy samples were assessed using a locally developed injury score.

RESULTS

Twenty patients (14 females, mean age 44.5 (SEM ± 2.9) years, mean BMI 60.8 (SEM ± 2.4) kg/m(2)) were recruited (NAC n = 10, control n = 10). The trial was stopped early after a planned interim analysis. Baseline liver function was similar. The peak rise in liver enzymes was on day 1, but levels were not significantly different between the groups. Rates of complications and length of stay were not significantly different. Secondary outcome measures, including white cell count (WCC), cytokines and cytokeratin (CK)-18 fragments, were not different between groups. Liver injury scores did not differ significantly.

CONCLUSIONS

NAC did not reduce intraoperative liver injury in this small number of patients. The heterogenous nature of the study population, with differences in co-morbidities, body mass index and intraabdominal anatomy, leads to a varied post-operative inflammatory response. Significant hepatocyte injury occurs through both necrosis and apoptosis.

Serum uric acid: a new therapeutic target for nonalcoholic fatty liver disease

INTRODUCTION

Nonalcoholic fatty liver disease (NAFLD) is a major, worldwide public health problem. NAFLD is recognized as a major cause of liver-related morbidity and mortality. However, physicians are currently limited by available treatment options. Recently, numerous studies have reported a correlation between serum uric acid (SUA) and NAFLD with numerous clinical and experimental studies demonstrating a significant correlation. This review will focus on the role of SUA in the development of NAFLD and its potential role as a new target for therapeutic intervention.

AREAS COVERED

This review discusses SUA as a significant independent factor in the development of NAFLD. Moreover, we introduce the causal relationship between SUA, metabolic syndrome, and NAFLD. We discuss two major theories of insulin resistance and inflammasomes as potential explanations of the mechanistic link between SUA and NAFLD. In addition, we review current and emerging therapeutic medications to control appropriate SUA levels.

EXPERT OPINION

There is an urgent need to develop novel, safe and effective therapies for the growing NAFLD epidemic. Reduction of SUA may be a promising potential treatment for patients with NAFLD. Clinical studies are required to determine the therapeutic effect of attenuation of hyperuricemia in humans with NAFLD.

Duodenal-jejunal bypass surgery suppresses hepatic de novo lipogenesis and alleviates liver fat accumulation in a diabetic rat model

BACKGROUND

Duodenal-jejunal bypass (DJB) surgery can induce rapid and durable remission of type 2 diabetes mellitus (T2DM), but the intrinsic mechanisms remain to be elucidated. Recent studies indicated that improved hepatic insulin resistance and insulin signaling transduction might contribute to the diabetic control after DJB. Given the important role of liver adiposity in hepatic insulin resistance, this study was aimed at investigating the effects of DJB on glucose homeostasis and liver fat accumulation in a T2DM rat model induced by high-fat diet (HFD) and small dose of streptozotocin (STZ).

METHODS

Forty adult male diabetic rats induced by HFD and small dose of STZ were randomly assigned to sham and DJB groups. Body weight, calorie intake, hormone levels, glucose, and lipid parameters were measured at indicated time points. Subsequently, hepatic triglycerides (TG) content and the protein levels of sterol regulatory element binding protein-1 (SREBP-1), carbohydrate response element binding protein (ChREBP), fatty acid synthase (FAS), and acetyl-CoA carboxylase (ACC) were evaluated at 2 and 8 weeks postoperatively.

RESULTS

Compared with sham group, DJB induced rapid and significant improvements in glucose homeostasis and insulin sensitivity independently of weight loss and calorie restriction. The DJB-operated rats exhibited lower liver TG content and decreased hepatic SREBP-1, ChREBP, ACC, and FAS at 8 weeks postoperatively.

CONCLUSIONS

DJB alleviated hepatic fat accumulation and downregulated the key transcriptional regulators and enzymes involved in hepatic de novo lipogenesis, which might contribute to improved hepatic insulin sensitivity and glucose homeostasis after DJB.

Psychopharmacology and Bariatric Surgery

Currently, it has been demonstrated that psychotropic drugs, particularly antidepressants, are frequently prescribed for patients who seek bariatric surgery. Many bariatric surgery patients have a history of a mood disorder. Unlike medications for diabetes, hypertension or hyperlipidemia, which are generally reduced and at times discontinued, postsurgery antidepressants use is only slightly reduced. The Roux-en-Y procedure is most frequently associated with alteration in drug exposure. Medication disintegration, dissolution, absorption, metabolism and excretion have been found to be altered in postbariatric patients, although data are sparse at this time. This paper will review the current evidence regarding the effect of bariatric surgery on drug treatment including mechanism of interference as well as the extent of changes identified to date. Data will be presented as controlled trials followed by case series and reports.

Practical approach to non-alcoholic fatty liver disease in patients with diabetes

The prevalence of Type 2 diabetes is expected to increase in parallel with obesity rates and the ageing population. Recent studies show that Type 2 diabetes is associated with a twofold increase in the risk of non-alcoholic fatty liver disease, a leading cause of chronic liver disease. Individuals with non-alcoholic steatohepatitis, a more advanced stage of non-alcoholic fatty liver disease, are specifically at risk of developing fibrosis/cirrhosis (end-stage liver disease) and hepatocellular carcinoma; therefore, identifying individuals (with Type 2 diabetes) who are likely to develop hepatic complications is paramount. In the present clinical review, we discuss the potential impact of non-alcoholic fatty liver disease diagnosis on Type 2 diabetes, and the putative risk factors for developing non-alcoholic steatohepatitis and non-alcoholic steatohepatitis fibrosis. We highlight the limitations of currently used tools in non-alcoholic fatty liver disease diagnosis and staging, and provide an insight into future developments in the field. We present an example of a non-alcoholic fatty liver disease screening protocol and discuss the therapeutic options currently available to our patients.

Molecular mechanisms of fatty liver in obesity

Nonalcoholic fatty liver disease (NAFLD) covers a spectrum of liver disorders ranging from simple steatosis to advanced pathologies, including nonalcoholic steatohepatitis and cirrhosis. NAFLD significantly contributes to morbidity and mortality in developed societies. Insulin resistance associated with central obesity is the major cause of hepatic steatosis, which is characterized by excessive accumulation of triglyceride-rich lipid droplets in the liver. Accumulating evidence supports that dysregulation of adipose lipolysis and liver de novo lipogenesis (DNL) plays a key role in driving hepatic steatosis. In this work, we reviewed the molecular mechanisms responsible for enhanced adipose lipolysis and increased hepatic DNL that lead to hepatic lipid accumulation in the context of obesity. Delineation of these mechanisms holds promise for developing novel avenues against NAFLD.

Mechanistic link between nonalcoholic fatty liver disease and cardiometabolic disorders

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 can lead to NAFLD related with insulin resistance. Thus, individuals with obesity, insulin resistance, and dyslipidemia are at the greatest risk of developing NAFLD. Conversely, NAFLD is one of the phenotypes of insulin resistance or metabolic syndrome. Many researchers have discovered a close association between NAFLD and insulin resistance, and focused on the role of NAFLD in the development of type 2 diabetes. Further, substantial evidence has suggested the association between NAFLD and cardiovascular disease (CVD). In the current review, we provide a plausible mechanistic link between NAFLD and CVD and the potential of the former as a therapeutic target based on pathophysiology. We also discuss in detail about the role of insulin resistance, oxidative stress, low-grade inflammation, abnormal lipid metabolism, gut microbiota, changes of biomarkers, and genetic predisposition in the pathological linking between NAFLD and cardiometabolic disorders.

Patients With Roux-en-Y Gastric Bypass Require Increased Sedation During Upper Endoscopy

BACKGROUND & AIMS

After Roux-en-Y gastric bypass (RYGB), many patients experience changes in metabolism that could affect the amount of sedative they require. We assessed whether patients who have vs have not received RYGB have different sedation requirements during esophagogastroduodenoscopy (EGD).

METHODS

In a retrospective study, we collected data from patients who had received RYGB (n = 200; mean age, 45 years; 188 women; body mass index [BMI], 34.0 ± 7.1 kg/m2) or had not (controls, n = 200; mean age, 45 years; 188 women; BMI, 34.1 ± 7.2 kg/m2) and underwent EGD under conscious sedation from 2005 through 2010; groups were matched for age, sex, and BMI. Sedative doses were compared by using the Student t test. Multivariate linear regression was used to identify factors associated with sedation dose. We performed a subgroup analysis of RYGB patients who underwent EGD before and after RYGB, comparing sedative doses with a paired t test.

RESULTS

Patients with RYGB were given 132.4 ± 40.4 μg fentanyl and 5.4 ± 1.5 mg midazolam, whereas controls received 108.6 ± 31.6 μg fentanyl (P < .001) and 4.3 ± 1.2 mg midazolam (P < .001). Increased time from RYGB, higher American Society of Anesthesiologists class, and therapeutic procedure were associated with higher doses of sedation (P < .05). Thirty-two patients underwent EGD before and after RYGB. Patients were given 95.0 ± 39.0 μg fentanyl before RYGB and 130.5 ± 41.3 μg fentanyl afterward (P < .05); they were given 4.0 ± 1.0 mg midazolam before RYGB and 5.5 ± 1.7 mg midazolam afterward (P < .05).

CONCLUSIONS

Patients with RYGB require larger amounts of fentanyl and midazolam during EGD than patients without RYGB, despite similar age, sex, and BMI. Among patients who underwent EGD before and after RYGB, levels of drugs required for sedation increased after gastric bypass, despite weight loss.

Bariatric surgery and nonalcoholic fatty liver disease

The rising prevalence of nonalcoholic fatty liver disease (NAFLD) is associated with the increasing global pandemic of obesity. These conditions cluster with type II diabetes mellitus and the metabolic syndrome to result in obesity-associated liver disease. The benefits of bariatric procedures on diabetes and the metabolic syndrome have been recognized for some time, and there is now mounting evidence to suggest that bariatric procedures improve liver histology and contribute to the beneficial resolution of NAFLD in obese patients. These beneficial effects derive from a number of weight-dependent and weight-independent mechanisms including surgical BRAVE actions (bile flow changes, restriction of stomach size, anatomical gastrointestinal rearrangement, vagal manipulation, enteric hormonal modulation) and subsequent effects such as reduced lipid intake, adipocytokine secretion, modulation of gut flora, improvements in insulin resistance and reduced inflammation. Here, we review the clinical investigations on bariatric procedures for NAFLD, in addition to the mounting mechanistic data supporting these findings. Elucidating the mechanisms by which bariatric procedures may resolve NAFLD can help enhance surgical approaches for metabolic hepatic dysfunction and also contribute toward developing the next generation of therapies aimed at reducing the burden of obesity-associated liver disease.

Disease severity and staging of obesity: a rational approach to patient selection

The increasing prevalence of obesity places ever-increasing cost demands on healthcare systems. One million individuals are eligible for bariatric surgery in the UK, and yet less than 6000 bariatric procedures are performed annually. Bariatric surgery reverses or improves almost all the medical and psychosocial co-morbidities associated with obesity. Although the BMI is a simple method to estimate adiposity at a population level, it is relatively inaccurate within an individual and provides little-to-no indication of overall health status or disease severity. Staging systems overcome the inherent limitations of BMI and allow highly informed decision-making for an individual. At a societal level, this helps to identify those most likely to gain and maximise economic benefit. This review summarises the co-morbidities associated with obesity and the evidence for their improvement following surgery. The rationale for new staging criteria and appropriate patient selection are discussed.

The Global Nonalcoholic Fatty Liver Disease Epidemic: What a Radiologist Needs to Know

Nonalcoholic fatty liver disease (NAFLD) represents a spectrum of disorders from a benign steatosis to hepatocellular carcinoma (HCC). Metabolic syndrome, mainly obesity, plays an important role, both as an independent risk factor and in the pathogenesis of NAFLD. With the progressive epidemics of obesity and diabetes mellitus, the prevalence of NAFLD and its associated complications is expected to increase dramatically. Therapeutic strategies for treating NAFLD and metabolic syndrome, particularly obesity, are continuously being refined. Their goal is the prevention of NAFLD by the management of risk factors, prevention of progression of the disease, as well as management of complications, ultimately preventing morbidity and mortality. Optimal management of NAFLD and metabolic syndrome requires a multidisciplinary collaboration between the government as well as the health system including the nutritionist, primary care physician, radiologist, hepatologist, oncologist, and transplant surgeon. An awareness of the clinical presentation, risk factors, pathogenesis, diagnosis, and management is of paramount importance to a radiologist, both from the clinical perspective as well as from the imaging standpoint. With expertise in imaging modalities as well as minimally invasive percutaneous endovascular therapies, radiologists play an essential role in the comprehensive management, which is highlighted in this article, with cases from our practice. We also briefly discuss transarterial embolization of the left gastric artery (LGA), a novel method that promises to have an enormous potential in the minimally invasive management of obesity, with details of a case from our practice.

Fatty liver disease in diabetes mellitus

Non-alcoholic fatty liver disease (NAFLD) is highly prevalent in type 2 diabetes mellitus (T2DM), likely reflecting the frequent occurrence of obesity and insulin resistance in T2DM. NAFLD also can occur in type 1 DM (T1DM), but must be distinguished from the more common glycogen hepatopathy as a cause of hepatomegaly and liver function abnormalities in T1DM. Weight reduction achieved by diet and exercise is effective in preventing and treating NAFLD in obese diabetic subjects. Bariatric surgery also has been shown to reverse NAFLD in T2DM, and recently approved weight loss medications should be evaluated for their impact on the development and progression of NAFLD. There is limited evidence suggesting that specific drugs used for blood glucose control in T2DM [thiazolidinediones (TZDs), glucagon-like peptide-1 (GLP-1) analogs, and dipeptidyl peptidase-4 (DPP-4) inhibitors] and also statins may have a role in preventing or treating NAFLD in patients with diabetes.

Analysis of the liver lipidome reveals insights into the protective effect of exercise on high-fat diet-induced hepatosteatosis in mice

The accumulation of lipid at ectopic sites, including the skeletal muscle and liver, is a common consequence of obesity and is associated with tissue-specific and whole body insulin resistance. Exercise is well known to improve insulin resistance by mechanisms not completely understood. We performed lipidomic profiling via mass spectrometry in liver and skeletal muscle samples from exercise-trained mice to decipher the lipid changes associated with exercise-induced improvements in whole body glucose metabolism. Obesity and insulin resistance were induced in C57BL/6J mice by high-fat feeding for 4 wk. Mice then underwent an exercise training program (treadmill running) 5 days/wk (Ex) for 4 wk or remained sedentary (Sed). Compared with Sed, Ex displayed improved (P < 0.01) whole body metabolism as measured via an oral glucose tolerance test. Deleterious lipid species such as diacylglycerol (P < 0.05) and cholesterol esters (P < 0.01) that accumulate with high-fat feeding were decreased in the liver of trained mice. Furthermore, the ratio of phosphatidylcholine (PC) to phosphatidylethanolamine (PE) (the PC/PE ratio), which is associated with membrane integrity and linked to hepatic disease progression, was increased by training (P < 0.05). These findings occurred without corresponding changes in the skeletal muscle lipidome. A concomitant decrease (P < 0.05) was observed for the fatty acid transporters CD36 and FATP4 in the liver, suggesting that exercise stimulates a coordinated reduction in fatty acid entry into hepatocytes. Given the important role of the liver in the regulation of whole body glucose homeostasis, hepatic lipid regression may be a key component by which exercise can improve metabolism.

Diagnosis and management of cardiovascular risk in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is increasingly recognized as an important cardiovascular risk (CVR) factor. This is a narrative clinical review aimed at answering how diagnosis and management of CVR should be conducted in the individual patient with NAFLD. To this end, the authors performed an extensive search of the existing literature on PubMed (1993-2014) using pertinent keywords. To date, CVR among patients with NAFLD might be assessed with the Framingham risk score equation or other risk calculators, to be adapted to the true CVR in the specific population being assessed; however, the use of these CVR calculators needs to be validated by future studies in larger cohorts of NAFLD patients of various ethnic backgrounds in order to substantiate their clinical relevance as a foundation for the primary prevention of cardiovascular diseases in this group of patients. Early and aggressive drug treatment of CVR should be started in NAFLD patients with a history of cardiovascular events, established diabetes or who are at high (calculated) CVR. Whether such an aggressive pharmacological approach is also justified in patients with NAFLD, who are at intermediate or low CVR, remains debatable. Currently, there are no clinical trials showing that the treatment of NAFLD per se (either associated or unassociated with traditional CVR factors) will result in decreased risk of cardiovascular events. Accordingly, drug treatment should be better individualized, aiming at correcting all the coexisting cardio-metabolic risk factors of the individual patient with NAFLD. To this end, an overview of the lifestyle interventions and the available drugs is offered, emphasis being conveyed to statins and metformin, which promise to cover worrying complications of NAFLD such as the risk of developing hepatocellular carcinoma.

Non-alcoholic fatty liver disease: The diagnosis and management

Non-alcoholic fatty liver disease (NAFLD) is now the most frequent chronic liver disease that occurs across all age groups and is recognized to occur in 14%-30% of the general population, representing a serious and growing clinical problem due to the growing prevalence of obesity and overweight. Histologically, it resembles alcoholic liver injury but occurs in patients who deny significant alcohol consumption. NAFLD encompasses a spectrum of conditions, ranging from benign hepatocellular steatosis to inflammatory nonalcoholic steatohepatitis, fibrosis, and cirrhosis. The majority of hepatocellular lipids are stored as triglycerides, but other lipid metabolites, such as free fatty acids, cholesterol, and phospholipids, may also be present and play a role in disease progression. NAFLD is associated with obesity and insulin resistance and is considered the hepatic manifestation of the metabolic syndrome, a combination of medical conditions including type 2 diabetes mellitus, hypertension, hyperlipidemia, and visceral adiposity. Confirmation of the diagnosis of NAFLD can usually be achieved by imaging studies; however, staging the disease requires a liver biopsy. Current treatment relies on weight loss and exercise, although various insulin-sensitizing agents, antioxidants and medications appear promising. The aim of this review is to highlight the current information regarding epidemiology, diagnosis, and management of NAFLD as well as new information about pathogenesis, diagnosis and management of this disease.

Duodenal jejunal bypass attenuates non-alcoholic fatty liver disease in western diet-obese rats

PURPOSE

To evaluate the effects of duodenal-jejunal bypass (DJB) on serum and hepatic profiles of obese rats fed on a western diet (WD).

METHODS

Twenty eight male Wistar rats were fed a standard rodent chow diet (CTL group) or WD ad libitum. After 10 weeks, WD rats were submitted to sham (WD SHAM) or duodenal-jejunal bypass (WD DJB). Body weight, fat pad depots, glycemia, insulinemia, HOMA-IR, TyG, lipids profile and hepatic analyses were evaluated two months after surgery.

RESULTS

The WD SHAM group presented greater obesity, hyperglycemia, hyperinsulinemia, insulin resistance, hypertriglyceridemia and hepatic steatosis than the CTL group. WD DJB rats presented decreased serum glucose and insulin resistance, when compared to WD SHAM animals, without changes in insulinemia. In addition, DJB surgery normalized serum TG and attenuated TG accumulation and steatosis in the liver of the WD DJB group. Hepatic ACC and FAS protein expressions were similar in all groups.

CONCLUSION

Duodenal-jejunal bypass attenuates hepatic parameters of non-alcoholic fatty liver disease in obese rats fed on a western diet.

Effect of Roux-en-Y gastric bypass and sleeve gastrectomy on nonalcoholic fatty liver disease: a comparative study

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease in the United States; 85%-95% of the morbidly obese population have NAFLD and 33% have nonalcoholic steatohepatitis. There is a lack of comparative data assessing various bariatric procedures and their effect on NAFLD.

OBJECTIVES

To assess and compare the effects of Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) on NAFLD.

SETTING

Academic Center, United States

METHODS

All bariatric cases performed at the authors' institution (an academic center in the United States) between 2005 and 2012 that had both intraoperative and postoperative liver biopsies were included. NAFLD Activity Score (NAS) and fibrosis stages were used to evaluate improvement in liver histology.

RESULTS

Fourteen RYGB and 9 SG patients with liver biopsies were identified. 57% and 73% in each group were female, respectively. P = .2. RYGB patients were older (56.2 ± 8.6 versus 46.3 ± 11.7; P<.05), and had lower initial body mass index (BMI) and higher NAS (51.0 ± 13.0 kg/m(2) versus 72.7 ± 21.0 kg/m(2); P<.05) and (4.4 ± 1.7 versus 2.6 ± 1.6; P<.05), respectively. Prevalence of co-morbidities was comparable between groups. After a mean follow-up of 1.5 years, weight loss percentage was 32% ± 11.8% and 25% ± 6.8% after RYGB and SG, respectively (P value not significant). Percentage of excess weight loss was higher in RYGB patients (69.8% ± 27% versus 37.2% ± 12.3%; P<.05). NAS after RYGB significantly improved in all morphologic characteristics, whereas only steatosis and total NAS improved after SG. Fibrosis state improved in both groups but to a greater degree after RYGB (2.5 ± 1.3 versus .3 ± .6; P< .05).

CONCLUSIONS

There were no significant differences in NAS score decrease after RYGB and SG procedures, although the baseline characteristics of the groups differ. This exploratory data supports the idea of conducting a randomized trial to determine the differential effects of SG and RYGB on NAFLD.

Non-alcoholic fatty liver disease: when to intervene and with what

Non-alcoholic fatty liver disease (NAFLD) is increasingly common due to the rising prevalence of obesity in both children and adults. It is associated with metabolic risk factors such as diabetes mellitus, dyslipidaemia and hypertension, and is associated with increased mortality both from cardiovascular-related and liver-related deaths. Identification of those individuals with significant inflammation and fibrosis is a critical part of the patient pathway. Current treatments for NAFLD include weight loss from lifestyle modification or bariatric surgery, management of underlying metabolic risk factors and for those with end stage liver disease, liver transplantation.

Evidence-based clinical practice guidelines for nonalcoholic fatty liver disease/nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) is currently the most common cause of chronic liver disease in industrialized countries worldwide, and has become a serious public health issue not only in Western countries but also in many Asian countries including Japan. Within the wide spectrum of NAFLD, nonalcoholic steatohepatitis (NASH) is a progressive form of disease, which often develops into liver cirrhosis and increases the risk of hepatocellular carcinoma. In turn, a large proportion of NAFLD/NASH is the liver manifestation of metabolic syndrome, suggesting that NAFLD/NASH plays a key role in the pathogenesis of systemic atherosclerotic diseases. Currently, a definite diagnosis of NASH requires liver biopsy, though various noninvasive measures are under development. The mainstays of prevention and treatment of NAFLD/NASH include dietary restriction and exercise; however, pharmacological approaches are often necessary. Currently, vitamin E and thiazolidinedione derivatives are the most evidence-based therapeutic options, although the clinical evidence for long-term efficacy and safety is limited. This practice guideline for NAFLD/NASH, established by the Japanese Society of Gastroenterology in cooperation with The Japan Society of Hepatology, covers lines of clinical evidence reported internationally in the period starting from 1983 to January 2012, and each clinical question was evaluated using the GRADE system. Based on the primary release of the full version in Japanese, this English summary provides the core essentials of this clinical practice guideline comprising the definition, diagnosis, and current therapeutic recommendations for NAFLD/NASH in Japan.

Evidence-based clinical practice guidelines for nonalcoholic fatty liver disease/nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) is currently the most common cause of chronic liver disease in industrialized countries worldwide, and has become a serious public health issue not only in Western countries but also in many Asian countries including Japan. Within the wide spectrum of NAFLD, non-alcoholic steatohepatitis (NASH) is a progressive form of disease, which often develops into liver cirrhosis and increases the risk of hepatocellular carcinoma. In turn, a large proportion of NAFLD/NASH is the liver manifestation of metabolic syndrome, suggesting that NAFLD/NASH plays a key role in the pathogenesis of systemic atherosclerotic diseases. Currently, a definite diagnosis of NASH requires liver biopsy, though various non-invasive measures are under development. The mainstays of prevention and treatment of NAFLD/NASH include dietary restriction and exercise; however, pharmacological approaches are often necessary. Currently, vitamin E and thiazolidinedione derivatives are the most evidence-based therapeutic options, although the clinical evidence for long-term efficacy and safety is limited. This practice guideline for NAFLD/NASH, established by the Japanese Society of Gastroenterology in cooperation with The Japan Society of Hepatology, covers lines of clinical evidence reported internationally in the period starting from 1983 through January 2012, and each clinical question was evaluated using the GRADE system. Based on the primary release of the full version in Japanese, this English summary provides the core essentials of this clinical practice guideline comprising the definition, diagnosis, and current therapeutic recommendations for NAFLD/NASH in Japan.

Total body weight loss of ≥ 10 % is associated with improved hepatic fibrosis in patients with nonalcoholic steatohepatitis

BACKGROUND

Given the rising epidemics of obesity and metabolic syndrome, nonalcoholic steatohepatitis (NASH) is now the most common cause of liver disease in the developed world. Effective treatment for NASH, either to reverse or prevent the progression of hepatic fibrosis, is currently lacking.

AIM

To define the predictors associated with improved hepatic fibrosis in NASH patients undergoing serial liver biopsies at prolonged biopsy interval.

METHODS

This is a cohort study of 45 NASH patients undergoing serial liver biopsies for clinical monitoring in a tertiary care setting. Biopsies were scored using the NASH Clinical Research Network guidelines. Fibrosis regression was defined as improvement in fibrosis score ≥1 stage. Univariate analysis utilized Fisher's exact or Student's t test. Multivariate regression models determined independent predictors for regression of fibrosis.

RESULTS

Forty-five NASH patients with biopsies collected at a mean interval of 4.6 years (±1.4) were included. The mean initial fibrosis stage was 1.96, two patients had cirrhosis and 12 patients (26.7 %) underwent bariatric surgery. There was a significantly higher rate of fibrosis regression among patients who lost ≥10 % total body weight (TBW) (63.2 vs. 9.1 %; p = 0.001) and who underwent bariatric surgery (47.4 vs. 4.5 %; p = 0.003). Factors such as age, gender, glucose intolerance, elevated ferritin, and A1AT heterozygosity did not influence fibrosis regression. On multivariate analysis, only weight loss of ≥10 % TBW predicted fibrosis regression [OR 8.14 (CI 1.08-61.17)].

CONCLUSION

Results indicate that regression of fibrosis in NASH is possible, even in advanced stages. Weight loss of ≥10 % TBW predicts fibrosis regression.

Indications and limitations of bariatric intervention in severely obese children and adolescents with and without nonalcoholic steatohepatitis: ESPGHAN Hepatology Committee Position Statement

Morbid obesity is strongly associated with nonalcoholic fatty liver disease (NAFLD), which is one of the most common causes of chronic liver disease worldwide. The present best treatment for NAFLD and nonalcoholic steatohepatitis (NASH) is weight reduction through lifestyle modification. Because of frustrating inefficiency of such a therapeutic approach, bariatric surgery is increasingly performed in adolescents as an alternative option for weight reduction. Standards of care and consensus for indications are, however, scarce. We explore the indications and limitations of bariatric surgery in children with severe obesity with and without NASH and aim to provide guidance for the exceptional indications for adolescents with extreme obesity with major comorbidity that may benefit from these controversial interventions. Present evidence suggests that bariatric surgery can decrease the grade of steatosis, hepatic inflammation, and fibrosis in NASH. Uncomplicated NAFLD is not an indication for bariatric surgery. Roux-en-Y gastric bypass is considered a safe and effective option for adolescents with extreme obesity, as long as an appropriate long-term follow-up is provided. Laparoscopic adjustable gastric banding has not been approved by the Food and Drug Administration for use in adolescents and therefore should be considered investigational. Finally, sleeve gastrectomy and other types of weight loss surgery that have grown increasingly common in adults, still need to be considered investigational. Temporary devices may be increasingly being used in pediatrics; however, future studies, including a long-term risk analysis of patients who undergo surgery, are much needed to clarify the exact indications for bariatric surgery in adolescents.

Effect of weight loss on magnetic resonance imaging estimation of liver fat and volume in patients with nonalcoholic steatohepatitis

BACKGROUND & AIMS

Little is known about how weight loss affects magnetic resonance imaging (MRI) of liver fat and volume or liver histology in patients with nonalcoholic steatohepatitis (NASH). We measured changes in liver fat and liver volume associated with weight loss by using an advanced MRI method.

METHODS

We analyzed data collected from a previous randomized controlled trial in which 43 adult patients with biopsy-proven NASH underwent clinical evaluation, biochemical tests, and MRI and liver biopsy analyses at the start of the study and after 24 weeks. We compared data between patients who did and did not have at least 5% decrease in body mass index (BMI) during the study period.

RESULTS

Ten of 43 patients had at least a 5% decrease in BMI during the study period. These patients had a significant decrease in liver fat, which was based on MRI proton density fat fraction estimates (18.3% ± 7.6% to 13.6% ± 13.6%, P = .03), a relative 25.5% reduction. They also had a significant decrease in liver volume (5.3%). However, no significant changes in levels of alanine aminotransferase or aspartate aminotransferase were observed with weight loss. Thirty-three patients without at least 5% decrease in BMI had insignificant increases in estimated liver fat fraction and liver volume.

CONCLUSIONS

A reduction in BMI of at least 5% is associated with significant decrease in liver fat and volume in patients with biopsy-proven NASH. These data should be considered in assessing effect size in studies of patients with nonalcoholic fatty liver disease or obesity that use MRI-estimated liver fat and volume as end points.

Bariatric surgery in patients with cirrhosis with and without portal hypertension: a single-center experience

OBJECTIVE

To assess safety and outcomes (metabolic and liver) of bariatric surgery in patients with cirrhosis with or without portal hypertension.

PATIENTS AND METHODS

This study is a retrospective review of 14 patients with Child's A cirrhosis with or without portal hypertension who were prospectively enrolled from February 23, 2009, through November 9, 2011, with 6- to 24-month follow-up after bariatric surgery (11 patients underwent sleeve gastrectomy [78.6%] and 3 gastric bypass [21.4%]). Four patients had portal hypertension detected by esophagogastroduodenoscopy.

RESULTS

The mean patient age was 55.5 years, and 10 of 14 patients were women. The mean weight decreased from 125±18 to 94±17 at 1 year (P<.001) and 93±17 kg at 2 years (P<.001) postsurgery. The prevalence of diabetes decreased from 10 of 14 patients to 4 of 12 (P=.01) and 1 of 6 (P=.02) at 1 and 2 years postsurgery. The frequency of dyslipidemia and hypertension decreased but was not statistically significant; however, the number of medications required to control them decreased. Hepatic steatosis was detected by perioperative liver biopsy in 13 of 14 patients (5%-30% steatosis in 6 patients, 31%-60% in 6, and >60% in 1). At 1 year postsurgery, only 1 of 8 patients who underwent follow-up ultrasound imaging showed evidence of steatosis. The bilirubin level was above 2 mg/dL in 1 patient at 1 year postsurgery. One patient had encephalopathy at 2 years postsurgery. None of the patients developed peri- or postoperative bleeding or surgical complications.

CONCLUSION

Bariatric surgery in patients with compensated cirrhosis even with mild portal hypertension is well tolerated and safe with minimal risk of postoperative complications if performed in a large referral center. This population can experience the beneficial effects of weight loss and improved metabolic syndrome, as well as reduced hepatic steatosis.

A concise review of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the hepatic manifestation of the metabolic syndrome and the incidence of which is rising rapidly due to the increasing epidemic of obesity in both adults and children. The initial accumulation of fat followed by subsequent inflammation is central to the development of liver damage, and is critically influenced by host factors including age, gender, presence of diabetes, genetic polymorphisms and more recently by the gut microbiome. An increasing body of data suggest that NAFLD is also an independent risk factor of cardiovascular disease, which remains the commonest cause of mortality in such patients. This review focusses on the pathogenesis of NAFLD, and the evolution of new approaches to the management and treatment of NAFLD.

Surgical treatment of nonalcoholic fatty liver disease in severely obese patients

Obesity is a multi-organ system disease with underlying metabolic abnormalities and chronic systemic inflammation. Nonalcoholic fatty liver disease (NAFLD) is a hepatic manifestation of obesity metabolic dysfunction and its associated cardiovascular- and liver-related morbidities and mortality. Our current understanding of NAFLD pathogenesis, disease characteristics, the role of insulin resistance, chronic inflammation, gut–liver and gut–brain crosstalk and the effectiveness of pharmacotherapy is still evolving. Bariatric surgery significantly improves metabolic and NAFLD histology in severely obese patients, although its positive effects on fibrosis are not universal. Bariatric surgery benefits NAFLD through its metabolic effect on insulin resistance, inflammation, and insulinotropic and anorexinogenic gastrointestinal hormones. Further studies are needed to understand the natural course of NAFLD in severely obese patients and the role of weight loss surgery as a primary treatment for NAFLD.

Review of nonalcoholic fatty liver disease in women with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in reproductive-aged women. Women with PCOS frequently have metabolic complications including insulin resistance (IR), early diabetes, hypertension and dyslipidemia. Recent studies have demonstrated an association between PCOS and another metabolic complication: nonalcoholic fatty liver disease (NAFLD). NAFLD occurs as a result of abnormal lipid handling by the liver, which sensitizes the liver to injury and inflammation. It can progress to nonalcoholic steatohepatitis (NASH), which is characterized by hepatocyte injury and apoptosis. With time and further inflammation, NASH can progress to cirrhosis. Thus, given the young age at which NAFLD may occur in PCOS, these women may be at significant risk for progressive hepatic injury over the course of their lives. Many potential links between PCOS and NAFLD have been proposed, most notably IR and hyperandrogenemia. Further studies are needed to clarify the association between PCOS and NAFLD. In the interim, clinicians should be aware of this connection and consider screening for NAFLD in PCOS patients who have other metabolic risk factors. The optimal method of screening is unknown. However, measuring alanine aminotransferase and/or obtaining ultrasound on high-risk patients can be considered. First line treatment consists of lifestyle interventions and weight loss, with possible pharmacologic interventions in some cases.

Non-alcoholic fatty liver disease in obese adults: clinical aspects and current management strategies

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disorder whose prevalence is strongly linked to the current epidemic of obesity in many western countries. The prevalence of NAFLD is two to four times higher in populations with pre-existing metabolic comorbidities than in the general population. The diagnosis of primary NAFLD involves establishing the presence of hepatic steatosis or steatohepatitis by imaging or histology, along with establishing the non-alcoholic nature of the disease process and excluding competing aetiologies for hepatic steatosis. Among the indirect serum biomarkers, the NAFLD fibrosis score can help to identify patients with NAFLD and with higher likelihood of having fibrosis or cirrhosis. A liver biopsy should be considered in NAFLD patients at increased risk for steatohepatitis/advanced fibrosis and in cases where a liver biopsy is necessary to exclude co-existing chronic liver diseases and other aetiologies for hepatic steatosis. The treatment and management recommendations for obesity-associated NAFLD are aimed towards weight reduction. The currently available interventions employed to promote weight loss and improve the metabolic responses in NAFLD include lifestyle modification, pharmacotherapy and bariatric surgery.

Non-alcoholic fatty liver disease: a practical approach to treatment

Non-alcoholic fatty liver disease (NAFLD) affects up to a third of the population in many developed countries. Between 10% and 30% of patients with NAFLD have non-alcoholic steatohepatitis (NASH) that can progress to cirrhosis. There are metabolic risk factors common to both NAFLD and cardiovascular disease, so patients with NASH have an increased risk of liver-related and cardiovascular death. Management of patients with NAFLD depends largely on the stage of disease, emphasising the importance of careful risk stratification. There are four main areas to focus on when thinking about management strategies in NAFLD: lifestyle modification, targeting the components of the metabolic syndrome, liver-directed pharmacotherapy for high risk patients and managing the complications of cirrhosis.

Non-alcoholic fatty liver disease: what the clinician needs to know

Non-alcoholic fatty liver disease (NAFLD) is the most frequent cause of liver disease in the Western world. Furthermore, it is increasing worldwide, paralleling the obesity pandemic. Though highly frequent, only about one fifth of affected subjects are at risk of developing the progressive form of the disease, non-alcoholic steatohepatitis with fibrosis. Even in the latter, liver disease is slowly progressive, though, since it is so prevalent, it is already the third cause of liver transplantation in the United States, and it is predicted to get to the top of the ranking in few years. Of relevance, fatty liver is also associated with increased overall mortality and particularly increased cardiovascular mortality. The literature and amount of published papers on NAFLD is increasing as fast as its prevalence, which makes it difficult to keep updated in this topic. This review aims to summarize the latest knowledge on NAFLD, in order to help clinicians understanding its pathogenesis and advances on diagnosis and treatment.

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.

Management of nonalcoholic fatty liver disease: an evidence-based clinical practice review

AIM

To build a consensus among Chilean specialists on the appropriate management of patients with nonalcoholic fatty liver disease (NAFLD) in clinical practice.

METHODS

NAFLD has now reached epidemic proportions worldwide. The optimal treatment for NAFLD has not been established due to a lack of evidence-based recommendations. An expert panel of members of the Chilean Gastroenterological Society and the Chilean Hepatology Association conducted a structured analysis of the current literature on NAFLD therapy. The quality of the evidence and the level of recommendations supporting each statement were assessed according to the recommendations of the United States Preventive Services Task Force. A modified three-round Delphi technique was used to reach a consensus among the experts.

RESULTS

A group of thirteen experts was established. The survey included 17 open-ended questions that were distributed among the experts, who assessed the articles associated with each question. The levels of agreement achieved by the panel were 93.8% in the first round and 100% in the second and third rounds. The final recommendations support the indication of lifestyle changes, including diet and exercise, for all patients with NAFLD. Proven pharmacological therapies include only vitamin E and pioglitazone, which can be used in nondiabetic patients with biopsy-proven nonalcoholic steatohepatitis (the progressive form of NAFLD), although the long-term safety and efficacy of these therapies have not yet been established.

CONCLUSION

Current NAFLD management is rapidly evolving, and new pathophysiology-based therapies are expected to be introduced in the near future. All NAFLD patients should be evaluated using a three-focused approach that considers the risks of liver disease, diabetes and cardiovascular events.

Surgery for weight loss in adults

BACKGROUND

Bariatric (weight loss) surgery for obesity is considered when other treatments have failed. The effects of the available bariatric procedures compared with medical management and with each other are uncertain. This is an update of a Cochrane review first published in 2003 and most recently updated in 2009.

OBJECTIVES

To assess the effects of bariatric surgery for overweight and obesity, including the control of comorbidities.

SEARCH METHODS

Studies were obtained from searches of numerous databases, supplemented with searches of reference lists and consultation with experts in obesity research. Date of last search was November 2013.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing surgical interventions with non-surgical management of obesity or overweight or comparing different surgical procedures.

DATA COLLECTION AND ANALYSIS

Data were extracted by one review author and checked by a second review author. Two review authors independently assessed risk of bias and evaluated overall study quality utilising the GRADE instrument.

MAIN RESULTS

Twenty-two trials with 1798 participants were included; sample sizes ranged from 15 to 250. Most studies followed participants for 12, 24 or 36 months; the longest follow-up was 10 years. The risk of bias across all domains of most trials was uncertain; just one was judged to have adequate allocation concealment.All seven RCTs comparing surgery with non-surgical interventions found benefits of surgery on measures of weight change at one to two years follow-up. Improvements for some aspects of health-related quality of life (QoL) (two RCTs) and diabetes (five RCTs) were also found. The overall quality of the evidence was moderate. Five studies reported data on mortality, no deaths occurred. Serious adverse events (SAEs) were reported in four studies and ranged from 0% to 37% in the surgery groups and 0% to 25% in the no surgery groups. Between 2% and 13% of participants required reoperations in the five studies that reported these data.Three RCTs found that laparoscopic Roux-en-Y gastric bypass (L)(RYGB) achieved significantly greater weight loss and body mass index (BMI) reduction up to five years after surgery compared with laparoscopic adjustable gastric banding (LAGB). Mean end-of-study BMI was lower following LRYGB compared with LAGB: mean difference (MD) -5.2 kg/m² (95% confidence interval (CI) -6.4 to -4.0; P < 0.00001; 265 participants; 3 trials; moderate quality evidence). Evidence for QoL and comorbidities was very low quality. The LRGYB procedure resulted in greater duration of hospitalisation in two RCTs (4/3.1 versus 2/1.5 days) and a greater number of late major complications (26.1% versus 11.6%) in one RCT. In one RCT the LAGB required high rates of reoperation for band removal (9 patients, 40.9%).Open RYGB, LRYGB and laparoscopic sleeve gastrectomy (LSG) led to losses of weight and/or BMI but there was no consistent picture as to which procedure was better or worse in the seven included trials. MD was -0.2 kg/m² (95% CI -1.8 to 1.3); 353 participants; 6 trials; low quality evidence) in favour of LRYGB.  No statistically significant differences in QoL were found (one RCT). Six RCTs reported mortality; one death occurred following LRYGB. SAEs were reported by one RCT and were higher in the LRYGB group (4.5%) than the LSG group (0.9%). Reoperations ranged from 6.7% to 24% in the LRYGB group and 3.3% to 34% in the LSG group. Effects on comorbidities, complications and additional surgical procedures were neutral, except gastro-oesophageal reflux disease improved following LRYGB (one RCT). One RCT of people with a BMI 25 to 35 and type 2 diabetes found laparoscopic mini-gastric bypass resulted in greater weight loss and improvement of diabetes compared with LSG, and had similar levels of complications.Two RCTs found that biliopancreatic diversion with duodenal switch (BDDS) resulted in greater weight loss than RYGB in morbidly obese patients. End-of-study mean BMI loss was greater following BDDS: MD -7.3 kg/m² (95% CI -9.3 to -5.4); P < 0.00001; 107 participants; 2 trials; moderate quality evidence). QoL was similar on most domains. In one study between 82% to 100% of participants with diabetes had a HbA1c of less than 5% three years after surgery. Reoperations were higher in the BDDS group (16.1% to 27.6%) than the LRYGB group (4.3% to 8.3%). One death occurred in the BDDS group.One RCT comparing laparoscopic duodenojejunal bypass with sleeve gastrectomy versus LRYGB found BMI, excess weight loss, and rates of remission of diabetes and hypertension were similar at 12 months follow-up (very low quality evidence). QoL, SAEs and reoperation rates were not reported. No deaths occurred in either group.One RCT comparing laparoscopic isolated sleeve gastrectomy (LISG) versus LAGB found greater improvement in weight-loss outcomes following LISG at three years follow-up (very low quality evidence). QoL, mortality and SAEs were not reported. Reoperations occurred in 20% of the LAGB group and in 10% of the LISG group.One RCT (unpublished) comparing laparoscopic gastric imbrication with LSG found no statistically significant difference in weight loss between groups (very low quality evidence).  QoL and comorbidities were not reported. No deaths occurred. Two participants in the gastric imbrication group required reoperation.

AUTHORS' CONCLUSIONS

Surgery results in greater improvement in weight loss outcomes and weight associated comorbidities compared with non-surgical interventions, regardless of the type of procedures used. When compared with each other, certain procedures resulted in greater weight loss and improvements in comorbidities than others. Outcomes were similar between RYGB and sleeve gastrectomy, and both of these procedures had better outcomes than adjustable gastric banding. For people with very high BMI, biliopancreatic diversion with duodenal switch resulted in greater weight loss than RYGB. Duodenojejunal bypass with sleeve gastrectomy and laparoscopic RYGB had similar outcomes, however this is based on one small trial. Isolated sleeve gastrectomy led to better weight-loss outcomes than adjustable gastric banding after three years follow-up. This was based on one trial only.  Weight-related outcomes were similar between laparoscopic gastric imbrication and laparoscopic sleeve gastrectomy in one trial. Across all studies adverse event rates and reoperation rates were generally poorly reported. Most trials followed participants for only one or two years, therefore the long-term effects of surgery remain unclear.

Non-alcoholic fatty liver disease, obesity and the metabolic syndrome

Nonalcoholic fatty liver disease (NAFLD) is now recognized as the most common cause of chronic liver disease worldwide. Its prevalence has increased to more than 30% of adults in developed countries and its incidence is still rising. The majority of patients with NAFLD have simple steatosis but in up to one third of patients, NAFLD progresses to its more severe form nonalcoholic steatohepatitis (NASH). NASH is characterized by liver inflammation and injury thereby determining the risk to develop liver fibrosis and cancer. NAFLD is considered the hepatic manifestation of the metabolic syndrome. However, the liver is not only a passive target but affects the pathogenesis of the metabolic syndrome and its complications. Conversely, pathophysiological changes in other organs such as in the adipose tissue, the intestinal barrier or the immune system have been identified as triggers and promoters of NAFLD progression. This article details the pathogenesis of NAFLD along with the current state of its diagnosis and treatment.

Sleep apnea and fatty liver disease: The growing link and management issues

Obstructive sleep apnea (OSA) is associated with metabolic, cardiovascular and neuropsychological disorders, with substantial morbidity and economic costs. OSA has been estimated to affect 4%-11% of the population, depending on age. Obesity is a significant risk factor for OSA. Non alcoholic fatty liver disease (NAFLD) has emerged as an integral component of the metabolic syndrome, with insulin resistance as the central pathogenic feature. Estimates based on imaging and autopsy studies suggest that about 20%-30% of adults in the United States and other Western countries have NAFLD. Evidence now suggests that NAFLD is independently correlated to insulin resistance regardless of adiposity. Some authors have suggested that OSA may be another contributor to NAFLD development. In complex diseases, several or many different genes interact with environmental factors in determining disease presence or its phenotype. Individual genes only have a small effect on disease risk and can therefore be very difficult to identify. The genetic and hormonal determinants of OSA and NAFLD have received little attention. A wide variety of intermediate phenotypes and genes are involved in OSA and NAFLD which makes this syndrome genetically complex. Various adipokines, the most important of which are leptin, adiponectin, tumor necrosis factor-alpha, resistin and interleukin-6, have a key role in NAFLD and OSA. Some studies have suggested that oxidative stress may also contribute to the development of NAFLD and OSA. Lifestyle intervention, insulin sensitizer drugs and bariatric surgery aim to improve metabolic syndrome, OSA and NAFLD but need further investigation.

Treatment of non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is now the commonest cause of chronic liver disease in developed countries. Treatment depends on the stage of disease, and non-invasive methods for risk stratification are urgently needed. Lifestyle modification (aimed at weight loss and increasing physical activity) and management of the features of metabolic syndrome are vital for all patients with NAFLD. Metformin is the first-line therapy for diabetic patients with NAFLD and also reduces the risk of hepatocellular carcinoma. Clinicians should have a low threshold for introducing a statin for the management of dyslipidaemia. Antihypertensive agents that target the renin-angiotensin system should be first-line in NAFLD for the management of hypertension. For patients with progressive disease, liver-directed pharmacotherapy with vitamin E should be considered. Non-alcoholic steatohepatitis cirrhosis is an increasingly common indication for liver transplantation.

Non-alcoholic fatty liver disease and diabetes: From physiopathological interplay to diagnosis and treatment

Non-alcoholic fatty liver disease (NAFLD) is highly prevalent in patients with diabetes mellitus and increasing evidence suggests that patients with type 2 diabetes are at a particularly high risk for developing the progressive forms of NAFLD, non-alcoholic steatohepatitis and associated advanced liver fibrosis. Moreover, diabetes is an independent risk factor for NAFLD progression, and for hepatocellular carcinoma development and liver-related mortality in prospective studies. Notwithstanding, patients with NAFLD have an elevated prevalence of prediabetes. Recent studies have shown that NAFLD presence predicts the development of type 2 diabetes. Diabetes and NAFLD have mutual pathogenetic mechanisms and it is possible that genetic and environmental factors interact with metabolic derangements to accelerate NAFLD progression in diabetic patients. The diagnosis of the more advanced stages of NAFLD in diabetic patients shares the same challenges as in non-diabetic patients and it includes imaging and serological methods, although histopathological evaluation is still considered the gold standard diagnostic method. An effective established treatment is not yet available for patients with steatohepatitis and fibrosis and randomized clinical trials including only diabetic patients are lacking. We sought to outline the published data including epidemiology, pathogenesis, diagnosis and treatment of NAFLD in diabetic patients, in order to better understand the interplay between these two prevalent diseases and identify the gaps that still need to be fulfilled in the management of NAFLD in patients with diabetes mellitus.

Nonalcoholic fatty liver disease in severe obese patients, subjected to bariatric surgery

CONTEXT

Nonalcoholic fatty liver disease encompasses a spectrum of histopathological changes that range from simple steatosis to nonalcoholic steatohepatitis. Works suggest that iron (Fe) deposits in the liver are involved in the physiopathology of nonalcoholic steatohepatitis.

OBJECTIVE

The aim of this study was to determine the prevalence of simple steatosis and nonalcoholic steatohepatitis in patients with morbid obesity, subjected to bariatric surgery and to establish a correlation of the anatomopathological findings with the presence of liver fibrosis.

METHODS

A total of 250 liver biopsies were conducted in the transoperation of the surgeries.

RESULTS

Steatosis was present in 226 (90.4%) of the samples, 76 (30.4%) being classified as mild; 71 (28.4%) as moderate and 79 (31.6%) as intense. Nonalcoholic steatohepatitis was diagnosed in 176 (70.4%) cases, where 120 (48.4%) were mild; 50 (20%) were moderate, and 6 (2.4%) cases were intense. Fibrosis was referred to in 108 (43.2%) biopsies, 95 of which (38%) were mild; 2 (0.8%) were moderate; 7 (2.8%) were intense, and cirrhosis was diagnosed in 4 (1.6%) cases. There was a correlation between the degree of steatosis and the level of inflammatory activity (rs = 0.460; P<0.001) and between the degree of this activity and the degree of fibrosis (rs = 0.583; P<0.001). Only 13 (5.2%) samples showed Fe deposits.

CONCLUSION

There is a high prevalence of nonalcoholic steatohepatitis in these patients and a positive correlation of the degrees of nonalcoholic steatohepatitis with the intensity of fibrosis. The low prevalence of Fe deposits found makes it questionable that the presence of this ion has any participation in the physiopathogeny of nonalcoholic fatty liver disease.

Liver disease in the morbidly obese: a review of 1000 consecutive patients undergoing weight loss surgery

BACKGROUND

Liver disease among the morbidly obese is increasingly prevalent, contributing to significant morbidity. Obesity-related liver pathologies including nonalcoholic steatohepatitis (NASH) have become a leading cause for liver transplant. However, risk factors for developing severe liver disease in the morbidly obese remain unknown. The objective of this study was to determine the frequency of abnormal liver pathology and any relationship to patient-related factors.

METHODS

One thousand consecutive patients undergoing weight loss surgery were reviewed. All patients had a liver biopsy at the time of surgery. Frequency of benign pathology, steatosis, NASH, and fibrosis on pathologic examination of liver biopsy specimens were recorded. Pathologic findings were compared and analyzed to age and body mass index (BMI) of all patients.

RESULTS

All patients in the study population had a BMI>35 kg/m2. Of these patients, 80.2% had liver disease related to obesity on pathology, including 65.9% with steatosis (grade 1-3), and 14.3% with NASH and/or fibrosis. Mean BMI of patients with liver disease was 48.1 compared to a BMI of 47.7 with benign pathology (P=.523). Mean age of patients with and without abnormal pathology was 48.3 and 47.3, respectively (P=.294).

CONCLUSION

Liver disease is highly prevalent in the obese, but is not associated with increased age or BMI. Although all morbidly obese patients appear at significant risk for developing severe liver pathology, further risk factors are unknown.

Management of fatty liver disease with the metabolic syndrome

Non-alcoholic fatty liver disease (NAFLD) is the liver disease of this century, increasing in parallel with obesity, insulin resistance and the metabolic syndrome. NAFLD can be seen as a component of the metabolic syndrome, and as such, contributing as a risk factor for cardiovascular disease. In fact, these patients die more often from cardiovascular disease than from direct consequences of liver disease. In this review, we will summarize the data that link NAFLD as a central player in this dysmetabolism, as well as the evidence for appropriate therapy, in order to improve not only liver disease prognosis, but also the overall prognosis and risk of mortality, with particular focus on cardiovascular risk.

Pre-and-post transplant considerations in patients with nonalcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is currently the third most common indication for liver transplantation in the United States. With the growing incidence of obesity, NAFLD is expected to become the most common indication for liver transplantation over the next few decades. As the number of patients who have undergone transplantation for NAFLD increases, unique challenges have emerged in the management and long-term outcomes in patients. Risk factors such as obesity, hypertension, diabetes, and hyperlipidemia continue to play an important role in the pathogenesis of the disease and its recurrence. Patients who undergo liver transplantation for NAFLD have similar long-term survival as patients who undergo liver transplantation for other indications. Research shows that post-transplantation recurrence of NAFLD is commonplace with some patients progressing to recurrent non-alcoholic steatohepatitis and cirrhosis. While treatment of comorbidities is important, there is no consensus on the management of modifiable risk factors or the role of pharmacotherapy and immunosuppression in patients who develop recurrent or de novo NAFLD post-transplant. This review provides an outline of NAFLD as indication for liver transplantation with a focus on the epidemiology, pathophysiology and risk factors associated with this disease. It also provides a brief review on the pre-transplant considerations and post-transplant factors including patient characteristics, role of obesity and metabolic syndrome, recurrence and de novo NAFLD, outcomes post-liver transplantation, choice of medications, and options for immunosuppression.