Bariatric surgery and nonalcoholic fatty liver disease

Impact of gastric bypass surgery on the liver fibrosis of patients with extreme obesity and nonalcoholic fatty liver disease in 30-month follow-up

Roux-en-Y gastric bypass surgery (RYGB) has shown efficacy in weight loss, but its role in liver fibrosis remains unknown and contentious. The present study aimed to investigate the effect of RYGB on liver fibrosis measured by non-invasive methods and assess the impact of weight loss on hepatic fibrosis in the midterm follow-up after RYGB. This longitudinal study was conducted on patients with extreme obesity, and NAFLD referred for RYGB during 2016-2018 for 3 years after their surgery. A liver biopsy was performed intraoperatively. The patient demographics, anthropometrical parameters, biochemical variables, and Liver stiffness (LS) using two-dimensional shear-wave elastography were recorded and analyzed before and in short-term and midterm follow-ups. Fifty-four patients were included with a mean age of 40.3 years; 83.3% were women. At a median follow-up of 30 months (range: 24-36 months), the excessive body mass index loss of the patients was 78.1% and, a significant reduction was seen in LS measurement. Two patients (4%) had worsening showed in the fibrosis stage, 28 (54%) no change, and 24 (42%) showed improvement, 30 months after the surgery. Moreover, the liver fibrosis stage regressed to F0 in 91% of the patients. Hepatic fibrosis resolved in the midterm follow-up in some patients whose fibrosis had progressed and deteriorated in the short-term follow-up. In addition, Liver enzymes were decreased. RYGB seems to be an effective procedure for sustained weight loss and improved liver fibrosis in EO and NAFLD patients in midterm follow-up.

Comprehensive Review of Cardiovascular Disease Risk in Nonalcoholic Fatty Liver Disease

Nonalcoholic Fatty Liver Disease (NAFLD) is a growing global phenomenon, and its damaging effects in terms of cardiovascular disease (CVD) risk are becoming more apparent. NAFLD is estimated to affect around one quarter of the world population and is often comorbid with other metabolic disorders including diabetes mellitus, hypertension, coronary artery disease, and metabolic syndrome. In this review, we examine the current evidence describing the many ways that NAFLD itself increases CVD risk. We also discuss the emerging and complex biochemical relationship between NAFLD and its common comorbid conditions, and how they coalesce to increase CVD risk. With NAFLD's rising prevalence and deleterious effects on the cardiovascular system, a complete understanding of the disease must be undertaken, as well as effective strategies to prevent and treat its common comorbid conditions.

The Benefit of Bariatric Surgery on Histological Features of Metabolic Associated Fatty Liver Disease Assessed Through Noninvasive Methods

BACKGROUND

In patients with clinically severe obesity, metabolic associated fatty liver disease (MAFLD) and steatohepatitis are highly prevalent. There is a lack of prospective studies evaluating the impact of bariatric surgery (BS) on MAFLD using both noninvasive and histological criteria. The present study aims to assess the impact of BS on MAFLD using histological and biochemical criteria.

METHODS

This is a prospective study of 52 patients subjected to BS. Noninvasive fibrosis risk scores (NIFRS) along with anthropometric, clinical, and biochemical parameters were recorded pre- and 12 months post-BS. Liver biopsy was obtained in all individuals at baseline (wedge biopsy) and was repeated at 12 months (percutaneous Tru-cut) in those diagnosed with steatohepatitis. The primary outcome was the change in the degree of steatohepatitis and fibrosis. The secondary outcome was the change in scores for hepatocellular ballooning, lobular inflammation, steatosis, and fibrosis.

RESULTS

One year after BS, steatohepatitis resolved in core biopsies with no worsening of fibrosis in 95.7% of individuals (n = 21, 95% CI: 87.3-100), and 13 (56.5%) exhibited complete resolution. Of 15 patients with fibrosis at baseline, 13 (86.7%) showed improvement and 12 exhibited fibrosis resolution. The values of transaminases improved, but only gamma glutamyl transferase (GGT) showed statistical significance. Among the NIFRS, NAFLD fibrosis score (NFS) and Hepamet fibrosis score (HFS) showed significant improvement.

CONCLUSIONS

In the setting it was studied, BS improved or resolved steatohepatitis and fibrosis in patients with obesity. NIFRS, especially NFS and HFS, and levels of GGT could be used as markers of recovery of liver function after BS.

ACCURACY OF ELASTOGRAPHY IN THE ASSESSMENT OF REDUCTION IN LIVER STEATOSIS AND FIBROSIS IN THE EARLY POSTOPERATIVE PERIOD AFTER BARIATRIC SURGERY

BACKGROUND:

Nonalcoholic hepatic steatosis is found in most obese patients and has a strong association with metabolic syndrome. The Roux-en-Y gastric bypass and the sleeve gastrectomy are the two techniques of bariatric surgery. Patients who underwent bariatric surgery have regression of nonalcoholic steatohepatitis due to a reduction in body mass index and changes in incretin hormones.

AIMS:

This study aimed to analyze the acuity of elastography in the regression of hepatic steatosis and fibrosis in obese patients undergoing Roux-en-Y gastric bypass and sleeve gastrectomy 2 months after surgery.

METHODS:

Patients in the preoperative period of bariatric surgery underwent an anthropometric evaluation and hepatic elastography to quantify fibrosis and hepatic steatosis. Two months after surgery, the same evaluation was performed again.

RESULTS:

All 17 patients who met the inclusion criteria participated in the study. Out of this, nine underwent sleeve gastrectomy, and eight underwent Roux-en-Y gastric bypass. The Roux-en-Y gastric bypass group had lower fibrosis levels postoperatively compared to preoperatively (p=0.029, p<0.05). As for steatosis, patients who underwent Roux-en-Y gastric bypass had lower postoperative values (p=0.01, p<0.05). There was also a reduction in fibrosis postoperatively in the sleeve gastrectomy group compared to preoperatively (p=0.037, p<0.05).

CONCLUSIONS:

Elastography accurately demonstrated decreased hepatic steatosis and fibrosis in the early postoperative period of bariatric surgery. Moreover, Roux-en-Y gastric bypass and sleeve gastrectomy are suitable surgical methods to improve hepatic steatosis and fibrosis within 2 months postoperatively.

Bariatric Surgery and Liver Disease: General Considerations and Role of the Gut-Liver Axis

Weight loss is a therapeutic solution for many metabolic disorders, such as obesity and its complications. Bariatric surgery aims to achieve lasting weight loss in all patients who have failed after multiple dietary attempts. Among its many benefits, it has been associated with the regression of non-alcoholic fatty liver disease (NAFLD), which is often associated with obesity, with evidence of substantial improvement in tissue inflammation and fibrosis. These benefits are mediated not only by weight loss, but also by favorable changes in systemic inflammation and in the composition of the gut microbiota. Changes in microbial metabolites such as short-chain fatty acids (SCFAs), capable of acting as endocrine mediators, and bile acids (BAs) as well as modifications of the gut-brain axis, are among the involved mechanisms. However, not all bariatric surgeries show beneficial effects on the liver; those leading to malabsorption can cause liver failure or a marked worsening of fibrosis and the development of cirrhosis. Nevertheless, there are still many unclear aspects, including the extent of the benefits and the magnitude of the risks of bariatric surgery in cirrhotic patients. In addition, the usefulness and the safety of these procedures in patients who are candidates to or who have undergone liver transplant need solid supporting evidence. This paper aims to review literature data on the use of bariatric surgery in the setting of chronic liver disease.

BYPASS VS. SLEEVE AND ITS EFFECTS IN NON-ALCOHOLIC FATTY LIVER DISEASE: WHAT IS THE BEST TECHNIQUE?

Background:

Strongly associated with obesity, non-alcoholic fatty liver disease is considered the hepatic manifestation of the metabolic syndrome. It presents as simple steatosis and steatohepatitis, which can progress to cirrhosis and its complications. Among the therapeutic alternatives is bariatric surgery.

Aim:

To compare the effect of the two most frequent bariatric procedures (sleeve and bypass) on liver disease regarding to epidemiological, demographic, clinical and laboratory parameters.

Methods:

The results of intraoperative and 12 months after surgery liver biopsies were used. The NAFLD activity score (NAS) was used to assess and compare the stages of liver disease.

Results:

Sixteen (66.7%) patients underwent Bypass procedure and eight (33.3%) Sleeve. It was observed that the variation in the NAFLD activity score was significantly greater in the Bypass group than in Sleeve (p=0.028) and there was a trend regarding the variation in fibrosis (p=0.054).

Conclusion:

Both surgical techniques were effective in improving the hepatic histology of most operated patients. When comparing sleeve and bypass groups, bypass showed better results, according to the NAS score.

The metabolic and liver-related outcomes of bariatric surgery in adult patients with insulin-treated type 2 diabetes and nonalcoholic fatty liver disease at high risk of liver fibrosis

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) has become the most common cause of chronic liver disease, with a prevalence estimated to between 20% and 30% of the general population and approximately 70% of stage 2 obese people with type 2 diabetes (T2D) with normal liver enzymes.

OBJECTIVES

To investigate the metabolic and liver-related outcomes of bariatric surgery among patients with insulin-treated T2D and NAFLD who are at high risk of liver fibrosis.

SETTING

More than 600 locations within the United Kingdom.

METHODS

The study comprises a retrospective cohort comparison of patients with NAFLD and a fibrosis 4 (Fib-4) score > 1.45 who received a bariatric intervention versus comparable patients who received no bariatric intervention. Metabolic outcomes (glycated hemoglobin [HbA1C] level, weight, body mass index [BMI], and Fib-4 score) and composite liver-related outcomes (cirrhosis, portal hypertension, liver failure, and hepatoma) were compared between groups over a period of 5 years. The outcomes were adjusted for baseline and time-varying covariates.

RESULTS

The study sample included 4108 patients, 45 of whom underwent bariatric surgery. The mean age at baseline was 62.4 ± 12.4 years; 43.8% of patients were female; the mean weight was 89.5 ± 20.8 kg; the mean BMI was 31.7 ± 7.6 kg/m²; and the mean HbA1C level was 68.4 ± 16.7 mmol/mol. In addition, the median Fib-4 score was 2.3 (interquartile range, 1.7-4.2). During the 5 years during which follow-up outcomes were recorded, the weight and BMI reductions were significantly lowered compared with baseline in the bariatric surgery group. Similarly, the HbA1C levels were lower in the bariatric surgery group, with statistically significant differences observed in the first and second postintervention years (bariatric surgery versus non-bariatric surgery patient levels at 1 year, 63.1 mmol/mol versus 68.1 mmol/mol, respectively [P = .042], and at 2 years, 62.7 mmol/mol versus 68.1 mmol/mol, respectively [P = .028]). No significant difference was observed between groups in the proportion of patients with liver fibrosis or the likelihood of developing composite liver disease during the follow-up period (bariatric surgery group, 8.9%; non-bariatric surgery group, 4.7%; X² = 1.75; P = .18).

CONCLUSION

Bariatric surgery amongst patients with insulin-treated T2D with NAFLD who were at high risk of liver fibrosis was associated with significant improvements in metabolic outcomes. No significant adverse effects were observed with regards to liver-related outcomes.

Systematic review and meta-analysis of Roux-en-Y gastric bypass against laparoscopic sleeve gastrectomy for amelioration of NAFLD using four criteria

Nonalcoholic fatty liver disease (NAFLD) prevalence is rising worldwide, as a direct consequence of the obesity epidemic. Bariatric surgery provides proven NAFLD amelioration, although questions remain regarding whether Roux-en-Y gastric bypass (RYGB) or laparoscopic sleeve gastrectomy (LSG) is more effective. To answer this question, we conducted a systematic review and meta-analysis exclusively comparing RYGB and LSG for amelioration of NAFLD using 4 separate criteria: alanine transaminase, aspartate transaminase, NAFLD activity score, and NAFLD fibrosis score. Our search included 1290 initial studies, which were narrowed to 20 final studies in the meta-analysis. Overall, both RYGB and LSG significantly improved alanine transaminase, aspartate transaminase, NAFLD activity score, and NAFLD fibrosis score postoperatively. Direct comparisons of RYGB to LSG in any of the 4 criteria failed to demonstrate superiority. Our findings corroborate the current literature showing that bariatric surgery significantly improves biochemical and histologic parameters in patients with NAFLD. The novel individual comparisons of 4 criteria failed to show superiority between RYGB and LSG in ameliorating NAFLD. Despite several limitations, our study can assist clinicians by supporting the notion that RYGB and LSG may be equally efficacious in ameliorating NAFLD.

Association of non-alcoholic fatty liver disease with cardiovascular disease and subclinical atherosclerosis

Non-alcoholic fatty liver disease (NAFLD) refers to fatty infiltration of liver in the absence of significant alcohol intake, use of steatogenic medication, or hereditary disorders. It is a common cause of chronic liver disease with a worldwide estimated prevalence ranging from 6.3% to 33%. The NAFLD is considered a hepatic manifestation of the metabolic syndrome. Insulin resistance and increased oxidative stress are central to pathogenesis of NAFLD, and risk factors include metabolic syndrome, diabetes mellitus, obesity, lack of physical activity, smoking, and high fat diet. NAFLD is associated with higher mortality as compared to the general population with cardiovascular disease being the most common cause of death. The NAFLD is associated with a higher prevalence of subclinical atherosclerosis as evidenced by odds of higher coronary artery calcification, higher average and maximum carotid intima-media thickness. It is also associated with stiff arteries as evidenced by higher cardio-ankle vascular index and higher brachial-ankle pulse wave velocity. Increasing evidence has linked NAFLD with atherosclerotic cardiovascular diseases. The NAFLD is associated with a higher prevalence of coronary artery disease (CAD), more severe CAD, poor coronary collateral development, and higher incidence of coronary events. The NAFLD is also associated with ischemic stroke. Studies have shown that the association between NAFLD and atherosclerotic cardiovascular diseases is independent of shared risk factors.

CORRELATION BETWEEN NONALCOHOLIC FATTY LIVER DISEASE FEATURES AND LEVELS OF ADIPOKINES AND INFLAMMATORY CYTOKINES AMONG MORBIDLY OBESE INDIVIDUALS

ABSTRACT BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is the commonest hepatopathy worldwide. OBJECTIVE: To investigate the correlations between NAFLD histopathological features and the levels of adipokines (adiponectin, leptin, and resistin) and circulating inflammatory markers (interleukin-6 [IL-6], interleukin-8 [IL-8], tumor necrosis factor alpha [TNF-α], and C-reactive protein [CRP]). METHODS: This is an exploratory cross-sectional study, which enrolled 19 women with obesity who underwent bariatric surgery. Biochemical characteristics evaluated included the levels of adiponectin, leptin, resistin, IL-6, IL-8, TNF-α, and CRP. NAFLD was assessed through histological examination of liver biopsies carried out during the surgical procedures. RESULTS: The mean age of the study group was 37.3±8.2 years old; mean BMI was 36.2±2.5 kg/m2. Among individuals with liver fibrosis, the levels of IL-8 were significantly higher (24.4 ± 9.7 versus 12.7 ± 6.6; P=0.016726). The intensity of fibrosis presented a significant negative correlation with the levels of adiponectin (R= -0.49379; P=0.03166); i.e. the higher the levels of adiponectin, the lower the intensity of fibrosis. The intensity of steatohepatitis presented a significant negative correlation with the levels of adiponectin (R= -0.562321; P=0.01221); this means that the higher the levels of adiponectin, the lower the intensity of steatohepatitis. CONCLUSION: Adiponectin levels were inversely correlated with the severity of fibrosis and steatohepatitis, whereas IL-8 levels were higher in individuals with liver fibrosis among individuals with obesity and NAFLD undergoing bariatric surgery. The use of these markers to assess NAFLD may bring significant information within similar populations.

PNPLA3 rs738409 underlies treatment response in nonalcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) has now become the leading cause of chronic liver disease with its growing incidence worldwide. Patatin-like phospholipase domain-containing protein 3 (PNPLA3) rs738409 C > G reflects one of the critical genetic factors that confers high-risk to NAFLD. However, the role of PNPLA3 polymorphism in NAFLD treatment remains uncertain. Here, the present review reveals that NAFLD patients with G-allele at PNPLA3 rs738409 (PNPLA3 148M variant) are sensitive to therapies of lifestyle modification, dipeptidyl peptidase-4 inhibitors, and bariatric surgery. They exhibit much significant reduction of liver fat content, in concurrence with weigh loss and abolished insulin resistance, as compared to those of C-allele carriers. In contrast, patients bearing PNPLA3 rs738409 C-allele (PNPLA3 148I variant), instead of G-allele, demonstrate greater beneficial effects by omega-3 poly-unsaturated fatty acids and statin intervention. Improved adipose tissue-liver interaction and decrease in intrahepatic triglyceride efflux may contribute to the PNPLA3 rs738409 related diversities in therapeutic efficacy. Therefore, PNPLA3 rs738409 underlies the response to a variety of treatments, which warrants a personalized, precise medicine in NAFLD on the basis of genotype stratification.

Liver failure caused by prolonged state of malnutrition following bariatric surgery

Bariatric surgery is an effective tool in the treatment of patients with morbid obesity. In these case reports we describe 2 patients who developed liver failure after currently-practiced types of bariatric surgery, caused by a prolonged state of malnutrition provoked by psychiatric problems. Despite intensive guidance of a psychologist and dieticians after surgery, our patients deteriorated psychologically, resulting in a prolonged state of severe malnutrition and anorexia. Finally, a state of starvation was reached, passing a critical level of the liver capacity. Patients who present with signs of severe protein malnutrition after bariatric surgery should be closely monitored and checked for nutritional status. Specific attention should be given to patients who develop psychiatric problems post-bariatric surgery. If refeeding does not result in clinical improvement, reversal surgery should be considered in a timely manner.

Current Treatment of Nonalcoholic Fatty Liver Disease/Nonalcoholic Steatohepatitis

Treatment of nonalcoholic fatty liver disease (NAFLD)/nonalcoholic steatohepatitis (NASH) is focused on patients with NASH because they are at highest risk for progressive liver disease. Current first-line treatment consists of lifestyle modifications. Patients should lose at least 7% to 10% of body weight via a combination of physical exercise and calorie restriction dieting. Surgical or endoscopic surgery for weight loss can be considered in obese patients, depending on degree of excess body weight and comorbidities. There is no currently approved pharmacotherapy for NASH. Vitamin E and pioglitazone have the most evidence of therapeutic efficacy but have limitations. The treatment modality chosen should be individualized.

Gastric Plication Improves Glycemia Partly by Restoring the Altered Expression of Aquaglyceroporins in Adipose Tissue and the Liver in Obese Rats

BACKGROUND

Gastric plication is a minimally invasive bariatric surgical procedure, where the greater curvature is plicated inside the gastric lumen. Our aims were to analyze the effectiveness of gastric plication on the resolution of obesity, impaired glucose tolerance, and fatty liver in an experimental model of diet-induced obesity (DIO) and to evaluate changes in glycerol metabolism, a key substrate for adiposity and gluconeogenesis, in adipose tissue and the liver.

METHODS

Male Wistar DIO rats (n = 58) were subjected to surgical (sham operation and gastric plication) or dietary interventions [fed a normal diet (ND) or high-fat diet (HFD) or pair-fed to the amount of food eaten by gastric-plicated animals]. The expression of aquaglyceroporins (AQPs) in epididymal (EWAT) and subcutaneous (SCWAT) fat and the liver was analyzed by real-time PCR and Western blot.

RESULTS

Gastric plication did not result in a significant weight loss in DIO rats, showing a modest reduction in whole-body adiposity and hepatic steatosis. However, gastric-plicated animals exhibited an improvement in basal glycemia and glucose clearance, without changes in hepatic gluconeogenic genes. DIO was associated with an increase in glycerol, higher AQP3 and AQP7 in EWAT and SCWAT, and a decrease in hepatic AQP9. Gastric plication downregulated AQP3 in both fat depots without changes in adipose AQP7 and hepatic AQP9.

CONCLUSION

Gastric plication results in a modest reduction in adiposity and hepatosteatosis but restores glycemia by downregulating AQP3, which entails lower efflux of glycerol from fat, lower plasma glycerol availability, and a reduced use of glycerol as a substrate for hepatic gluconeogenesis.

Reciprocal interactions between bile acids and gut microbiota in human liver diseases

The gut microbiota (GM) play a central role in their host's metabolism of bile acids (BAs) by regulating deconjugation, dehydroxylation, dehydrogenation, and epimerization reactions to generate unconjugated free BAs and secondary BAs. These BAs generated by the GM are potent signaling molecules that interact with BA receptors, such as the farnesoid X receptor and Takeda G-protein-coupled receptor 5. Each BA has a differential affinity to these receptors; therefore, alterations in BA composition by GM could modify the intensity of receptor signaling. Bile acids also act as antimicrobial agents by damaging bacterial membranes and as detergents by altering intracellular macromolecular structures. Therefore, BAs and the GM reciprocally control each other's compositions. In this review, we discuss the latest findings on the mutual effects of BAs and GM on each other; we also describe their roles in the pathophysiology of liver disease progression and potential therapeutic applications of targeting this cross-talk.

Bile Acid Alterations Are Associated With Insulin Resistance, but Not With NASH, in Obese Subjects

CONTEXT

Bile acids (BAs) are signaling molecules controlling energy homeostasis that can be both toxic and protective for the liver. BA alterations have been reported in obesity, insulin resistance (IR), and nonalcoholic steatohepatitis (NASH). However, whether BA alterations contribute to NASH independently of the metabolic status is unclear.

OBJECTIVE

To assess BA alterations associated with NASH independently of body mass index and IR.

DESIGN AND SETTING

Patients visiting the obesity clinic of the Antwerp University Hospital (a tertiary referral facility) were recruited from 2006 to 2014.

PATIENTS

Obese patients with biopsy-proven NASH (n = 32) and healthy livers (n = 26) were matched on body mass index and homeostasis model assessment of IR.

MAIN OUTCOME MEASURES

Transcriptomic analyses were performed on liver biopsies. Plasma concentrations of 21 BA species and 7α-hydroxy-4-cholesten-3-one, a marker of BA synthesis, were determined by liquid chromatography-tandem mass spectrometry. Plasma fibroblast growth factor 19 was measured by enzyme-linked immunosorbent assay.

RESULTS

Plasma BA concentrations did not correlate with any hepatic lesions, whereas, as previously reported, primary BA strongly correlated with IR. Transcriptomic analyses showed unaltered hepatic BA metabolism in NASH patients. In line, plasma 7α-hydroxy-4-cholesten-3-one was unchanged in NASH. Moreover, no sign of hepatic BA accumulation or activation of BA receptors-farnesoid X, pregnane X, and vitamin D receptors-was found. Finally, plasma fibroblast growth factor 19, secondary-to-primary BA, and free-to-conjugated BA ratios were similar, suggesting unaltered intestinal BA metabolism and signaling.

CONCLUSIONS

In obese patients, BA alterations are related to the metabolic phenotype associated with NASH, especially IR, but not liver necroinflammation.

Biopsy-proven progressive fatty liver disease nine months post mini-gastric bypass surgery: A case study

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Performance of MGB with a 200 cm bypassed limb in a morbidly obese female.

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Presentation of anemia, low albumin, elevated LFT at 8th month despite good intake.

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NAFLD activity score progressed from 2/8 to 7/8, leading to revisional surgery.

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Rapid course of weight loss after BS and/or long bypassed limb could be responsible.

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Bowel length measurement is recommended to avoid a short common intestinal channel.

Introduction

Mini-gastric bypass (MGB) is a popular bariatric procedure. Its effect on non-alcoholic fatty liver disease (NAFLD), however, has not yet been comprehensively studied.

Presentation of case

A 57 year-old non-alcoholic female with a body mass index of 42.8 kg/m² underwent MGB without any incident. A concurrent liver biopsy showed an NAFLD activity score (NAS) of 2/8 without fibrosis. She presented at postoperative month eight with edema, vague abdominal pain, nausea, and vomiting and was hospitalized. Her BMI had dropped to 25.7 kg/m². Her blood workup revealed mild anemia, mildly elevated liver enzymes, and hypoalbuminemia (2.5 g/dL). Liver ultrasound revealed grade-2 fatty liver. She received parenteral nutrition and intensive nutrient supplementation. Nevertheless, with regard to unsuccessful supportive measures and rising liver enzymes, revisional surgery −gastrogastrostomy- was performed. Her liver biopsy demonstrated a NAS of 7/8 at the time of revisional surgery. Her postoperative course was uneventful and she was discharged after one week.

Discussion

Bariatric surgery has shown favorable results regarding improvement of NAFLD in morbid obesity. This beneficial effect has been linked to the amount of weight loss. However, case reports have shown deteriorating liver function and NAFLD even after significant weight loss. They all have in common significant weight loss in a relatively short period of time. There may also be a connection between specific bariatric surgery procedures and this phenomenon.

Conclusion

Future studies comparing the effect of various bariatric procedures, including MGB, are necessary to help clinicians decide the optimal procedure for patients with this liver condition.

Nonalcoholic fatty liver disease and bariatric surgery: a comprehensive review

CONTEXT AND OBJECTIVE:

Nonalcoholic fatty liver disease (NAFLD) has been increasingly diagnosed worldwide and is now recognized as a source of public health concern. It comprises a wide spectrum of histological features that range from simple steatosis to severe forms of fibrosis, steatohepatitis and even cirrhosis. The impact of bariatric surgery on the course of NAFLD in individuals with obesity has been extensively studied.

DESIGN AND SETTING:

Narrative review; public university hospital.

METHODS:

A comprehensive review was conducted based on an online search on the electronic databases MEDLINE and LILACS using the MeSH terms "fatty liver" and "bariatric surgery".

RESULTS:

The exact mechanisms that lead to improvement in NAFLD following bariatric surgery are not completely understood. Since Roux-en-Y gastric bypass (RYGB) is the bariatric surgical procedure most performed worldwide, it is also the one from which the effects on NAFLD have been most studied, although there is also consistent evidence regarding the effects from gastric banding, sleeve gastrectomy and biliopancreatic diversions.

CONCLUSION:

According to the currently available evidence, bariatric surgery leads to significant improvement in NAFLD. Further research, especially by means of randomized controlled trials enrolling larger cohorts of individuals, is needed to determine the optimal procedure for this group of subjects.

Bile acids and nonalcoholic fatty liver disease: Molecular insights and therapeutic perspectives

Nonalcoholic fatty liver disease (NAFLD) is a burgeoning health problem worldwide and an important risk factor for both hepatic and cardiometabolic mortality. The rapidly increasing prevalence of this disease and of its aggressive form nonalcoholic steatohepatitis (NASH) will require novel therapeutic approaches to prevent disease progression to advanced fibrosis or cirrhosis and cancer. In recent years, bile acids have emerged as relevant signaling molecules that act at both hepatic and extrahepatic tissues to regulate lipid and carbohydrate metabolic pathways as well as energy homeostasis. Activation or modulation of bile acid receptors, such as the farnesoid X receptor and TGR5, and transporters, such as the ileal apical sodium-dependent bile acid transporter, appear to affect both insulin sensitivity and NAFLD/NASH pathogenesis at multiple levels, and these approaches hold promise as novel therapies. In the present review, we summarize current available data on the relationships of bile acids to NAFLD and the potential for therapeutically targeting bile-acid-related pathways to address this growing world-wide disease. (Hepatology 2017;65:350-362).

Early effects of Roux-en-Y gastric bypass on peptides and hormones involved in the control of energy balance

INTRODUCTION

Body weight varies depending on the prevailing direction of environmental pressures; however, physiological factors also play a significant role in the control of body weight. The aim of the present study was to assess the impact of Roux-en-Y gastric bypass (RYGB) on hormones and peptides involved in the control of energy balance and their possible implications in appetite/satiety.

METHODS

The sample included 39 individuals with extreme obesity (37 women and two men) who underwent RYGB. Anthropometric and biochemical markers were collected before surgery and 6 months after RYGB.

RESULTS

The BMI decreased from 44.3±6.4 to 31.7±5.7 kg/m (P<0.001) at the sixth month. Percentage of excess weight lost was 63.2±25.0%. Leptin and glucose levels decreased significantly 6 months after RYGB (P<0.001). Interestingly, a significant correlation was confirmed between the anorexigenic gut hormone peptide YY (PYY) and the central anorexigenic mediator α-melanocyte-stimulating hormone after 6 months of RYGB (r=0.35, P=0.004). In contrast, PYY concentrations were correlated negatively with BMI (r=-0.34, P=0.002).

CONCLUSION

In the present investigation, it was found that there is a relationship between α-melanocyte-stimulating hormone and PYY concentrations, and it supports the role of the PYY to POMC signal in appetite regulation after RYGB.

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.