Impact of sleeve gastrectomy and Roux-en-Y gastric bypass on biopsy-proven non-alcoholic fatty liver disease

TREM2 macrophages mediate the beneficial effects of bariatric surgery against MASH

BACKGROUND AND AIMS

For patients with obesity and metabolic syndrome, bariatric procedures such as vertical sleeve gastrectomy (VSG) have a clear benefit in ameliorating metabolic dysfunction-associated steatohepatitis (MASH). While the effects of bariatric surgeries have been mainly attributed to nutrient restriction and malabsorption, whether immuno-modulatory mechanisms are involved remains unclear.

APPROACH AND RESULT

Using murine models, we report that VSG ameliorates MASH progression in a weight loss-independent manner. Single-cell RNA sequencing revealed that hepatic lipid-associated macrophages (LAMs) expressing the triggering receptor expressed on myeloid cells 2 (TREM2) repress inflammation and increase their lysosomal activity in response to VSG. Remarkably, TREM2 deficiency in mice ablates the reparative effects of VSG, suggesting that TREM2 is required for MASH resolution. Mechanistically, TREM2 prevents the inflammatory activation of macrophages and is required for their efferocytic function.

CONCLUSIONS

Overall, our findings indicate that bariatric surgery improves MASH through a reparative process driven by TREM2+ macrophages, providing insights into the mechanisms of disease reversal that may result in new therapies and improved surgical interventions.

PIM1 alleviated liver oxidative stress and NAFLD by regulating the NRF2/HO-1/NQO1 pathway

AIMS

Non-alcoholic fatty liver disease (NAFLD) has risen as a significant global public health issue, for which vertical sleeve gastrectomy (VSG) has become an effective treatment method. The study sought to elucidate the processes through which PIM1 mitigates the advancement of NAFLD. The Pro-viral integration site for Moloney murine leukemia virus 1 (PIM1) functions as a serine/threonine kinase. Bioinformatics analysis revealed that reduced PIM1 expression in NAFLD.

METHODS

To further prove the role of PIM1 in NAFLD, an in-depth in vivo experiment was performed, in which male C57BL/6 mice were randomly grouped to receive a normal or high-fat diet for 24 weeks. They were operated or delivered the loaded adeno-associated virus which the PIM1 was overexpressed (AAV-PIM1). In an in vitro experiment, AML12 cells were treated with palmitic acid to induce hepatic steatosis.

KEY FINDINGS

The results revealed that the VSG surgery and virus delivery of mice alleviated oxidative stress, and apoptosis in vivo. For AML12 cells, the levels of oxidative stress, apoptosis, and lipid metabolism were reduced via PIM1 upregulation. Moreover, ML385 treatment resulted in the downregulation of the NRF2/HO-1/NQO1 signaling cascade, indicating that PIM1 mitigates NAFLD by targeting this pathway.

SIGNIFICANCE

PIM1 alleviated mice liver oxidative stress and NAFLD induced by high-fat diet by regulating the NRF2/HO-1/NQO1 signaling Pathway.

Increase in bile acids after sleeve gastrectomy improves metabolism by activating GPBAR1 to increase cAMP in mice with nonalcoholic fatty liver disease

BACKGROUND

Bile acids (BAs) concentration can affect metabolic improvement caused by bariatric surgery and BA concentrations increase in patients after sleeve gastrectomy (SG). Here, how BAs after SG affect metabolism in nonalcoholic fatty liver disease (NAFLD) was studied.

METHODS

Mice were given high-fat diet (HFD) to induce NAFLD and received SG surgery. Hepatic and fecal BA concentrations in mice were detected by liquid chromatography-tandem mass spectrometry method. BA-related genes were detected by quantitative real-time polymerase chain reaction. G protein BA receptor 1 (GPBAR1) expression was identified using western blot analysis. NAFLD mice after SG received GPBAR1 inhibitor Triamterene. The weight of mice and mice liver was detected. Mouse liver tissue was observed by hematoxylin-eosin and Oil Red O staining. Triglyceride (TG), nonesterified fatty acid (NEFA), and cyclic adenosine monophosphate (cAMP) levels in mouse liver tissue were analyzed by metabolic assay and enzyme-linked immune sorbent assay.

RESULTS

SG boosted increase in hepatic total/conjugated BAs and related genes and GPBAR1 expression, and attenuated increase in fecal total BAs/muricholic acid in HFD-induced mice and increased fecal taurine-BAs in HFD-induced mice. Triamterene (72 mg/kg) reversed the inhibitory role of SG in HFD-induced increase of body weight, lipid accumulation, inflammatory cell infiltration, and increase of hepatic weight and TG/NEFA content, and counteracted the positive role of SG in HFD-induced increase of hepatic cAMP concentration in mice.

CONCLUSIONS

BAs improve metabolism via activating GPBAR1 to increase cAMP in NAFLD mice after SG.

Laparoscopic Roux-en-Y Versus Mini-Gastric Bypass on Liver Function at 6 Months in Morbid Obesity Patients: A Cross-Sectional Study

Background: Various weight loss surgeries exist, with no absolute superiority; each has pros and cons. Due to rising bariatric surgeries globally, it's vital to investigate comparisons between two-mini gastric bypass and Roux-en-Y gastric bypass (RYGB), especially regarding their impact on liver function. Objectives: The purpose of this study was to "draw comparisons between the effects of mini gastric bypass and laparoscopic Roux-en-Y gastric bypass on liver function at 6 months among patients with morbid obesity." Methods: This cross-sectional study included 90 bariatric surgery candidates (Body Mass Index (BMI) 35 - 50) from 2018 - 2021. Forty-five had laparoscopic mini gastric bypass surgery, while 45 had Roux-en-Y gastric bypass. Demographic, anthropometric, lab, and sonographic tests were conducted at baseline, 3-, and 6-months post-surgery. Data was analyzed using SPSS. Results: In a study of 90 patients (75.6% female, mean age 38.6 ± 10.4 years), both surgeries (Mini gastric bypass (MGB) and RYGB) effectively reduced body weight, BMI, and waist circumference at 3- and 6-months post-surgery. However, MGB showed significantly higher BMI and weight loss compared to RYGB (P = 0.003). In 90 patients, both surgeries reduced weight and BMI. However, MGB showed better BMI/weight loss. LFTs (ALT, AST, ALP) remained stable after MGB but worsened at 3 months after RYGB before recovering by 6 months. Mini gastric bypass also showed better GGT improvement. Both procedures improved fatty liver grading, FBS, and HbA1C levels equally. No significant differences were observed in blood pressure, platelet count, hemoglobin, or MCV. Ferritin levels increased in both groups but were higher in RYGB. CRP was higher in RYGB at 3 months. Conclusions: Roux-en-Y gastric bypass temporarily exacerbated liver enzymes and inflammation, but MGB resulted with more weight reduction. In comparison to RYGB, MGB improved LFTs more consistently.

Effects of laparoscopic sleeve gastrectomy on nonalcoholic fatty liver disease and TGF-β signaling pathway

Nonalcoholic fatty liver disease (NAFLD) develops as a result of unhealthy lifestyle but improves with laparoscopic sleeve gastrectomy (LSG). The transforming growth factor (TGF)-β signaling pathway reportedly contributes to liver fibrosis, mainly in animal experiments. The aim of the present study was to evaluate changes in serum proteins before and after LSG by proteomic analysis and to investigate their association with NAFLD. This study enrolled 36 severely obese patients who underwent LSG at our hospital from January 2020 to April 2022. As a pilot study, proteomic analysis was conducted on six patients using serum collected before and at 6 months after LSG, and significantly fluctuating proteins were extracted. Subsequently, verification by enzyme-linked immunosorbent assay (ELISA) using collected serum was performed on the remaining 30 patients. The mean weight of enrolled patients was 118.5 kg. Proteomic analysis identified 1,912 proteins, many of which were related to the TGF-β signaling pathway. Among these proteins, we focused on five TGF-β-related proteins: asporin, EMILIN-1, platelet factor-4, serglycin, and thrombospondin-1. Verification by ELISA revealed that asporin (p = 0.006) and thrombospondin-1 (p = 0.043) levels significantly fluctuated before and after LSG. Univariate analysis with a linear regression model showed that aspartate aminotransferase (p = 0.045), asporin (p = 0.011), and thrombospondin-1 (p = 0.022) levels were significantly associated with postoperative liver fibrosis. On multivariate analysis, asporin was an independent prognostic factor for postoperative liver fibrosis (95% confidence interval: 0.114-1.291, p = 0.002). TGF-β-related proteins dramatically fluctuated before and after LSG and were correlated with NAFLD pathogenesis. Asporin may be a useful prognostic marker of liver fibrosis in NAFLD after LSG.

Hepatic lipid-associated macrophages mediate the beneficial effects of bariatric surgery against MASH

For patients with obesity and metabolic syndrome, bariatric procedures such as vertical sleeve gastrectomy (VSG) have a clear benefit in ameliorating metabolic dysfunction-associated steatohepatitis (MASH). While the effects of bariatric surgeries have been mainly attributed to nutrient restriction and malabsorption, whether immuno-modulatory mechanisms are involved remains unclear. Here we report that VSG ameliorates MASH progression in a weight loss-independent manner. Single-cell RNA sequencing revealed that hepatic lipid-associated macrophages (LAMs) expressing the triggering receptor expressed on myeloid cells 2 (TREM2) increase their lysosomal activity and repress inflammation in response to VSG. Remarkably, TREM2 deficiency in mice ablates the reparative effects of VSG, suggesting that TREM2 is required for MASH resolution. Mechanistically, TREM2 prevents the inflammatory activation of macrophages and is required for their efferocytotic function. Overall, our findings indicate that bariatric surgery improves MASH through a reparative process driven by hepatic LAMs, providing insights into the mechanisms of disease reversal that may result in new therapies and improved surgical interventions.

How far are we from an approved drug for nonalcoholic steatohepatitis?

INTRODUCTION

Metabolic-associated fatty liver disease (MAFLD) previously known but still debatable, as nonalcoholic fatty liver disease (NAFLD) is one of the main causes of chronic liver disease and subsequent cirrhosis worldwide, accounting for around 30% of liver diseases. The change in its nomenclature has been brought about by the novel discoveries regarding its pathogenesis, in which metabolic dysfunction plays the most important role. It is widely known that for every disease, the treatment should always be targeted toward the underlying etiology and pathogenesis.

AREAS COVERED

MAFLD/NAFLD pathogenesis is heterogeneous, and includes multiple gene polymorphisms, presence of insulin resistance, as well as concomitant diseases that contribute to the disease onset and progression. As a result of this, even though lifestyle modification (owing to metabolic abnormalities) is the first line of treatment, multiple drugs have been tested to target each of the known pathways leading to MAFLD/NAFLD and progression of steatohepatitis. We aim to review the most relevant information regarding previous and ongoing research and recommendations regarding treatment of MAFLD/NAFLD.

EXPERT OPINION

Combination therapies associated to weight loss and exercise will be the optimal approach for these patients. It is important to evaluate each patient to select the specific combination according to patient characteristics.

Approach to the Patient With Nonalcoholic Fatty Liver Disease

CONTEXT

Nonalcoholic fatty liver disease (NAFLD) is associated with obesity and type 2 diabetes (T2D), causing substantial burden from hepatic and extrahepatic complications. However, endocrinologists often follow people who are at the highest risk of its more severe form with nonalcoholic steatohepatitis or NASH (i.e., T2D or obesity with cardiometabolic risk factors). Endocrinologists are in a unique position to prevent cirrhosis in this population with early diagnosis and treatment.

OBJECTIVE

This work aims to offer endocrinologists a practical approach for the management of patients with NAFLD, including diagnosis, fibrosis risk stratification, and referral to hepatologists.

PATIENTS

(1) An asymptomatic patient with obesity and cardiometabolic risk factors, found to have hepatic steatosis; (2) a patient with T2D and NASH with clinically significant liver fibrosis; and (3) a liver transplant recipient with a history of NASH cirrhosis, with significant weight regain and with recurrent NAFLD on the transplanted organ.

CONCLUSION

NASH can be reversed with proper management of obesity and of T2D. While no agents are currently approved for the treatment of NASH, treatment should include lifestyle changes and a broader use of structured weight-loss programs, obesity pharmacotherapy, and bariatric surgery. Diabetes medications such as pioglitazone and some glucagon-like peptide 1 receptor agonists may also improve liver histology and cardiometabolic health. Sodium-glucose cotransporter-2 inhibitors and insulin may ameliorate steatosis, but their effect on steatohepatitis remains unclear. Awareness by endocrinologists about, establishing an early diagnosis of fibrosis (ie, FIB-4, liver elastography) in patients at high-risk of cirrhosis, long-term monitoring, and timely referral to the hepatologist are all critical to curve the looming epidemic of cirrhosis from NAFLD.

Bariatric Surgery Associates with Nonalcoholic Steatohepatitis/Hepatocellular Carcinoma Amelioration via SPP1 Suppression

Nonalcoholic steatohepatitis (NASH) is one of the most common chronic liver diseases worldwide and no effective drugs or treatments have been approved for disease management. Recently, bariatric surgery (BS) is considered to be a novel disease-modifying therapy for NASH and liver metabolic diseases, according to clinical follow-up studies. Despite the revealment of physiopathological alterations, underlying mechanisms and key factors remain indeterminate. This study included multiple bulk RNA-sequencing datasets to investigate transcriptome variation in one-year follow-up BS and diet management (Diet) NASH patients' liver biopsies. Liver functions, fibrosis, and carcinogenesis were predicted in liver samples via hallmark-based function enrichment analysis. Key factors generated from multi-dataset comparison were further assessed with hepatocellular carcinoma (HCC) progression and prognosis. BS leads to active gene expression alterations in NASH liver in comparison to diet management (Diet). Both approaches reduce cell stress and immune response, whereas BS contributes to higher metabolic levels and lower apoptosis levels. The macrophage infiltration, adipose accumulation, and fibroblast activation were revealed to be lower in post-BS NASH livers, further demonstrating positive correlations mutually. Seven key genes (MNDA, ALOX5AP, PECAM1, SPP1, CD86, FGF21, CSTA) were screened out as potential macrophage-associated and carcinogenetic factors suppressed by BS. SPP1 was identified as a crucial factor participating in BS intervened NASH-HCC progression. This study determined that BS exerts potentially superior protective functions in NASH livers compared to diet management. SPP1 may serve as a novel factor to study the functionalities of BS on NASH patients.

Bariatric surgery for diabetic comorbidities: A focus on hepatic, cardiac and renal fibrosis

Continuously rising trends in diabetes render this disease spectrum an epidemic proportion worldwide. As the disease progresses, the pathological effects of diabetes may impair the normal function of several vital organs, eventually leading to increase the risk of other diabetic comorbidities with advanced fibrosis such as non-alcoholic fatty liver disease, diabetic cardiomyopathy, and diabetic kidney disease. Currently, lifestyle changes and drug therapies of hypoglycemic and lipid-lowering are effective in improving multi-organ function, but therapeutic efficacy is difficult to maintain due to poor compliance and drug reactions. Bariatric surgery, including sleeve gastrectomy and Roux-en-Y gastric bypass surgery, has shown better results in terms of prognosis for diabetes through long-term follow-up. Moreover, bariatric surgery has significant long-term benefits on the function of the heart, liver, kidneys, and other organs through mechanisms associated with reversal of tissue fibrosis. The aim of this review is to describe the impact of type 2 diabetes mellitus on hepatic, cardiac and renal fibrosis and to summarize the potential mechanisms by which bariatric surgery improves multiple organ function, particularly reversal of fibrosis.

Nonalcoholic fatty liver disease and diabetes

Nonalcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease in the world and represents a clinical-histopathologic entity where the steatosis component may vary in degree and may or may not have fibrotic progression. The key concept of NAFLD pathogenesis is excessive triglyceride hepatic accumulation because of an imbalance between free fatty acid influx and efflux. Strong epidemiological, biochemical, and therapeutic evidence supports the premise that the primary pathophysiological derangement in most patients with NAFLD is insulin resistance; thus the association between diabetes and NAFLD is widely recognized in the literature. Since NAFLD is the hepatic manifestation of a metabolic disease, it is also associated with a higher cardio-vascular risk. Conventional B-mode ultrasound is widely adopted as a first-line imaging modality for hepatic steatosis, although magnetic resonance imaging represents the gold standard noninvasive modality for quantifying the amount of fat in these patients. Treatment of NAFLD patients depends on the disease severity, ranging from a more benign condition of nonalcoholic fatty liver to nonalcoholic steatohepatitis. Abstinence from alcohol, a Mediterranean diet, and modification of risk factors are recommended for patients suffering from NAFLD to avoid major cardiovascular events, as per all diabetic patients. In addition, weight loss induced by bariatric surgery seems to also be effective in improving liver features, together with the benefits for diabetes control or resolution, dyslipidemia, and hypertension. Finally, liver transplantation represents the ultimate treatment for severe nonalcoholic fatty liver disease and is growing rapidly as a main indication in Western countries. This review offers a comprehensive multidisciplinary approach to NAFLD, highlighting its connection with diabetes.

Bariatric Surgery is Effective and Safe for Obese Patients with Compensated Cirrhosis: A Systematic Review and Meta-Analysis

BACKGROUND

With the global pandemic of obesity and nonalcoholic fatty liver disease (NAFLD), the incidence of cirrhosis associated with nonalcoholic steatohepatitis (NASH) has greatly increased. This study aimed to evaluate the efficacy and safety of bariatric surgery in obese cirrhotic patients.

METHODS

PubMed, EMBASE, and the Cochrane Library were searched for relevant studies. Effectiveness outcomes were weight loss, remission of comorbidities, and improvement in liver function. Safety outcomes were procedural complications and mortality.

RESULTS

A total of 15 studies were included in this meta-analysis. Patients with compensated cirrhosis lost weight significantly after surgery, and the percentage of excess weight loss was 60.44 (95% CI, 44.34 to 76.55). Bariatric surgery resulted in remission of NAFLD in 57.9% (95% CI, 27.5% to 88.3%), T2DM in 58.4% (95% CI, 48.4% to 68.4%), hypertension in 53.1% (95% CI, 43% to 63.3%), dyslipidemia in 59.8% (95% CI, 41.1% to 78.5%) of patients with cirrhosis. Bariatric surgery reduced the levels of alanine aminotransferase and aspartate aminotransferase. The incidence of surgical complications in patients with cirrhosis was about 19.2% (95% CI, 11.7% to 26.6%), which was higher than that in patients without cirrhosis (OR 2.67 [95% CI, 1.26 to 5.67]). Patients with cirrhosis had an overall mortality rate of 1.3%, and the mortality rates for compensated cirrhosis and decompensated cirrhosis were 0.9% and 18.2%, respectively.

CONCLUSIONS

Bariatric surgery is effective for weight loss, remission of comorbidities, and reversal of liver damage. Although cirrhotic patients have a higher risk of complications and death, bariatric surgery is relatively safe for well-compensated cirrhosis.

Liver Injury and Acute Liver Failure After Bariatric Surgery: An Overview of Potential Injury Mechanisms

The obesity epidemic has caused a surge in the use of bariatric surgery. Although surgery-induced weight loss is an effective treatment of nonalcoholic fatty liver disease, it may precipitate severe hepatic complications under certain circumstances. Acute liver injury (ALI) and acute liver failure (ALF) following bariatric surgery have been reported in several case series. Although rare, ALI and ALF tend to emerge several months after bariatric surgery. If so, it can result in prolonged hospitalization, may necessitate liver transplantation, and in some cases prove fatal. However, little is known about the risk factors for developing ALI or ALF after bariatric surgery and the mechanisms of liver damage in this context are poorly defined. This review provides an account of the available data on ALI and ALF caused by bariatric surgery, with emphasis on potential injury mechanisms and the outcomes of liver transplantation for ALF after bariatric surgery.

Is there an 'ideal' diet for patients with NAFLD?

Nonalcoholic fatty liver disease (NAFLD) is a growing epidemic that encompasses three distinct clinical phenotypes: uncomplicated fatty liver, nonalcoholic steatohepatitis (NASH) and NASH-related cirrhosis with its complications, including hepatocellular carcinoma. To date, no pharmacological treatments have been approved and lifestyle modifications including reduced caloric intake targeting a 7%-10% weight loss from baseline assessment represent the standard approach. Mediterranean diet has been recommended as the best dietary pattern since it is easy to follow and, independently of caloric intake its nutritional components have beneficial metabolic effects that not only improve steatosis but also risk factors for cardiovascular events, the leading cause of morbidity/mortality in individuals with NAFLD. Other dietary patterns such as ketogenic diet and Dietary Approach to Stop Hypertension (DASH) diet can be used in patients with NAFLD. Recently, intermittent fasting diets have gained popularity among healthy individuals and have been proposed as a safe and effective treatment for the metabolic syndrome in experimental and in a few human studies. In this narrative review, we aim to summarize the evidence for the available dietary approaches for patients with NAFLD.

The Concept of Indeterminable NASH Inducted by Preoperative Diet and Metabolic Surgery: Analyses of Histopathological and Clinical Features

Practitioners routinely perform intraoperative liver biopsies during laparoscopic sleeve gastrectomy (LSG) to evaluate nonalcoholic fatty liver disease (NAFLD). In some patients, hepatocyte ballooning, inflammation, and fibrosis without steatosis are observed, even in the absence of other etiologies. We call this finding indeterminable nonalcoholic steatohepatitis (Ind-NASH). In this study, we clarified the prevalence, as well as histopathological and clinical features, of Ind-NASH through intraoperative liver biopsy in Japanese patients presenting with severe obesity. We enrolled 63 patients who had undergone LSG and intraoperative liver biopsy. In patients diagnosed with histopathological NASH, we performed protocol liver biopsies at 6 and 12 months after LSG. We statistically analyzed these histopathological findings and clinical parameters and found the prevalence rate of Ind-NASH discovered through intraoperative biopsy to be 15.9%. Protocol liver biopsy also revealed that Ind-NASH was an intermediate condition between NASH and normal liver. The clinical features of patients with Ind-NASH are a higher body weight compared to NASH (134.9 kg vs. 114.7 kg; p = 0.0245), stronger insulin resistance compared to nonalcoholic fatty liver (homeostasis model assessment–insulin resistance: 7.1 vs. 4.9; p = 0.0188), and mild liver dysfunction compared to NASH. Patients with Ind-NASH observed positive weight-loss effects from a preoperative diet compared to the postoperative course (percentage total weight loss: 32.0% vs. 26.7%; p < 0.0001). Patients with Ind-NASH may also be good candidates for metabolic surgery owing to their good treatment response; therefore, efforts should be made by specialists in the near future to deeply discuss and define Ind-NASH.

Fasting, Nutrition and Weight Loss: An Approach to Refine Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is considered as one of the most common causes of chronic liver disease. It includes a group of conditions associated with fat deposition in liver cells. Also, NAFLD is strongly associated with obesity and insulin resistance (IR). Until now, there is no pharmacological treatment validated for this disease. Fasting, nutritional intervention, and weight loss can be considered the first line in treating hepatic steatosis. This review is based on the scientific evidence showing the results of these interventions in the past years. The results include fasting and nutritional support for NAFLD treatment in humans. In clinical trials and cohort studies, an increase in hepatic fat content was correlated with a weight loss of at least 7% and a diet resembling the Mediterranean diet (MD) improving hepatic biomarkers and histological regression of NAFLD. Fasting is a dietary approach known to improve the lipid profile in healthy and obese populations by decreasing overall cholesterol, triglycerides, LDL, and increasing HDL. Bariatric surgery helps improve liver fat content in patients with serious health problems due to overweight.

MiR-200c-3p Regulates DUSP1/MAPK Pathway in the Nonalcoholic Fatty Liver After Laparoscopic Sleeve Gastrectomy

AIM

Non-alcoholic fatty liver disease (NAFLD) is a health burden worldwide, which is closely related to obesity. The effect of sleeve gastrectomy (SG) on NAFLD is efficient, and the underlying mechanism remains unknown. Our study sought to investigate the mechanism of dual-specificity protein phosphatase 1 (DUSP1) expression regulation following the SG procedure in NAFLD patients and C57BL/6J mice via miR-200c-3p.

METHODS

The serum was extracted from NAFLD patients who underwent laparoscopic sleeve gastrectomy (LSG) and volunteers. Next, the correlation between miR-200c-3p and DUSP1 was identified in vitro. NAFLD mice were modelled by high-fat diets (HFD). The hepatic tissue expression levels of miR-200c-3p, DUSP1, phospho-extracellular regulated protein kinases1/2 (p-ERK1/2), phospho -p38 mitogen-activated protein kinases (p-p38), and phospho-c-Jun N-terminal kinases (p-JNK) induced by SG procedure were evaluated.

RESULTS

The SG procedure contributed to significant weight loss, reduced lipids in NAFLD patients and mice. The increased expression level of miR-200c-3p and reduced expression of DUSP1 were observed in NAFLD patients and mice (p<0.05). The reduced expression levels of miR-200c-3p and increased expression of DUSP1 were observed in patients and mice with NAFLD who underwent SG procedure. DUSP1 is a potential target of miR-200c-3p.

CONCLUSIONS

A novel mechanism was identified in which miR-200c-3p regulates the MAPK-dependent signals that are linked to the promotion of hepatosteatosis via DUSP1 after sleeve gastrectomy. The findings suggested that miR-200c-3p should be further explored as a potential target for the treatments of NAFLD.

Safety of liver biopsy at the time of bariatric surgery: an analysis of the MBSAQIP database

BACKGROUND

The majority of patients undergoing bariatric surgery have hepatic steatosis. Liver biopsy is not technically difficult to perform at the time of metabolic and bariatric surgery (MBS), but there may be concerns for bleeding complications. The safety of liver biopsy (LBx) at the time of MBS has been studied in single institutional studies but has not been studied on a national level.

METHODS

The MBSAQIP database for 2015-2018 was examined. The codes for Roux-en-Y gastric bypass (RYGB) of 43644 and sleeve gastrectomy (SG) 43775 were used along with 47000 (percutaneous liver biopsy), 47001 (percutaneous liver biopsy at time of other procedure), and 47379 (unlisted laparoscopic procedure, liver). Outcomes such as operative time, complications, and length of stay were examined. Propensity-matched analysis was performed to evaluate for adjusted associations.

RESULTS

There were 546,532 patients that met our inclusion criteria. Of those, 21,367 (3.9%) underwent LBx. Only 5.5% (8012) of patients undergoing RYGB had a LBx and 3.3% (13,355) of SG patients. Patients who underwent a LBx had a longer operative time before (103 min vs 84 min, p < 0.001) and after propensity matching [regression coefficient (RC): 10.7 (8.87, 12.5)]. There was no increase in length of stay. There was an increased risk in mortality in the unadjusted analysis (prevalence ratio = 1.61, p = 0.02), but when propensity-matched analysis was done, there was no statistically significant difference between the two groups. Concerning bleeding or transfusion, there was no difference in bleeding or rates of transfusion (p= 0.22, p = 0.21).

CONCLUSION

Liver biopsy at the time of MBS is safe. It adds operative time, but there is no increase in length of stay, bleeding complications, morbidity, or death.

Non-Alcoholic Fatty Liver Disease (NAFLD) and Bariatric/Metabolic Surgery as Its Treatment Option: A Review

The prevalence of non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) has considerably increased over the last years. NAFLD is currently the most common cause of chronic liver disease in the developing world. The diagnosis of NAFLD/NASH is often incidental, as the early-stage of disease is frequently free of symptoms. Most patients recognized with NAFLD have severe obesity and other obesity-related disease such as type 2 diabetes mellitus (T2DM), insulin-resistance, dyslipidemia and hypertension. The only proven method for NAFLD improvement and resolution is weight loss. Bariatric surgery leads to significant and long-term weight loss as well as improvement of coexisting diseases. There is a lot of evidence suggesting that metabolic/bariatric surgery is an effective method of NAFLD treatment that leads to reduction in steatosis, hepatic inflammation and fibrosis. However, there is still a need to perform long-term studies in order to determine the role of bariatric surgery as a treatment option for NAFLD and NASH. This review discusses current evidence about epidemiology, pathogenesis and treatment options for NAFLD including bariatric/metabolic surgery and its effect on improvement and resolution of NAFLD.

Role of ANGPTL8 in NAFLD Improvement after Bariatric Surgery in Experimental and Human Obesity

Angiopoietin-like protein 8 (ANGPTL8) is an hepatokine altered in several metabolic conditions, such as obesity, type 2 diabetes, dyslipidemia and nonalcoholic fatty liver disease (NAFLD). We sought to explore whether ANGPTL8 is involved in NAFLD amelioration after bariatric surgery in experimental models and patients with severe obesity. Plasma ANGPTL8 was measured in 170 individuals before and 6 months after bariatric surgery. Hepatic ANGPTL8 expression was evaluated in liver biopsies of patients with severe obesity undergoing bariatric surgery with available liver pathology analysis (n = 75), as well as in male Wistar rats with diet-induced obesity subjected to sham operation, sleeve gastrectomy or Roux-en-Y gastric bypass (RYGB) (n = 65). The effect of ANGPTL8 on lipogenesis was assessed in human HepG2 hepatocytes under palmitate-induced lipotoxic conditions. Plasma concentrations and hepatic expression of ANGPTL8 were increased in patients with obesity-associated NAFLD in relation to the degree of hepatic steatosis. Sleeve gastrectomy and RYGB improved hepatosteatosis and reduced the hepatic ANGPTL8 expression in the preclinical model of NAFLD. Interestingly, ANGPTL8 inhibited steatosis and expression of lipogenic factors (PPARG2, SREBF1, MOGAT2 and DGAT1) in palmitate-treated human hepatocytes. Together, ANGPTL8 is involved in the resolution of NAFLD after bariatric surgery partially by the inhibition of lipogenesis in steatotic hepatocytes.

Current Options and Future Directions for NAFLD and NASH Treatment

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide, with a broad spectrum ranging from simple steatosis to advanced stage of nonalcoholic steatohepatitis (NASH). Although there are many undergoing clinical trials for NAFLD treatment, there is no currently approved treatment. NAFLD accounts as a major causing factor for the development of hepatocellular carcinoma (HCC), and its incidence rises accompanying the prevalence of obesity and diabetes. Reprogramming of antidiabetic and anti-obesity medicine is a major treatment option for NAFLD and NASH. Liver inflammation and cellular death, with or without fibrosis account for the progression of NAFLD to NASH. Therefore, molecules and signaling pathways involved in hepatic inflammation, fibrosis, and cell death are critically important targets for the therapy of NAFLD and NASH. In addition, the avoidance of aberrant infiltration of inflammatory cytokines by treating with CCR antagonists also provides a therapeutic option. Currently, there is an increasing number of pre-clinical and clinical trials undergoing to evaluate the effects of antidiabetic and anti-obesity drugs, antibiotics, pan-caspase inhibitors, CCR2/5 antagonists, and others on NAFLD, NASH, and liver fibrosis. Non-invasive serum diagnostic markers are developed for fulfilling the need of diagnostic testing in a large amount of NAFLD cases. Overall, a better understanding of the underlying mechanism of the pathogenesis of NAFLD is helpful to choose an optimized treatment.

Gut Microbiome and Metabolites in Patients with NAFLD and after Bariatric Surgery: A Comprehensive Review

The prevalence of non-alcoholic fatty liver disease (NAFLD) is increasing, as are other manifestations of metabolic syndrome such as obesity and type 2 diabetes. NAFLD is currently the number one cause of chronic liver disease worldwide. The pathophysiology of NAFLD and disease progression is poorly understood. A potential contributing role for gut microbiome and metabolites in NAFLD is proposed. Currently, bariatric surgery is an effective therapy to prevent the progression of NAFLD and other manifestations of metabolic syndrome such as obesity and type 2 diabetes. This review provides an overview of gut microbiome composition and related metabolites in individuals with NAFLD and after bariatric surgery. Causality remains to be proven. Furthermore, the clinical effects of bariatric surgery on NAFLD are illustrated. Whether the gut microbiome and metabolites contribute to the metabolic improvement and improvement of NAFLD seen after bariatric surgery has not yet been proven. Future microbiome and metabolome research is necessary for elucidating the pathophysiology and underlying metabolic pathways and phenotypes and providing better methods for diagnostics, prognostics and surveillance to optimize clinical care.

Effects of Laparoscopic Sleeve Gastrectomy on Non-Alcoholic Steatohepatitis and Liver Fibrosis in Japanese Patients with Severe Obesity

BACKGROUND

The prevalence of non-alcoholic steatohepatitis (NASH) in Japanese patients with severe obesity is extremely high. The aim of the present study was to evaluate the metabolic and histological effects of laparoscopic sleeve gastrectomy (LSG) on NASH and liver fibrosis in Japanese patients with severe obesity.

METHODS

Between June 2008 and March 2019, all 79 patients with severe obesity who underwent LSG were included in the study. Sixty-eight patients had an intraoperative liver biopsy performed at the time of LSG. Ultrasound-guided liver biopsies were performed in patients with fibrosis at 12 months after LSG.

RESULTS

NASH was present in 43 patients (63.2%), and 10 patients had a unique feature in which their fibrosis were observed without steatosis at the time of LSG. Of the 28 patients with NASH, 25 showed improvement and no longer met the diagnostic criteria of NASH at 12 months after LSG. Mean pericellular fibrosis scores showed significant improvement from 1.62 at baseline, to 1.50, 1.00, and 0.78, respectively (p < 0.001). Univariate analysis of the preoperative predictors in the improvement of fibrosis showed significant effects in preoperative weight (p = 0.037), HbA1c (p = 0.037), and serum insulin (p = 0.037). Multivariate analysis revealed HbA1c to be the only preoperative predictor of improvement in fibrosis (p = 0.004; odds ratio 0.440, 95% CI 0.229-0.842).

CONCLUSIONS

LSG has great potential as an effective treatment for patients with NASH.

Gastric Bypass Compared with Sleeve Gastrectomy for Nonalcoholic Fatty Liver Disease: a Systematic Review and Meta-analysis

The effects of bariatric procedures on nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) remain unclear. A systematic review and meta-analysis was performed to compare the impact of Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) on NAFLD/NASH. Patients submitted to RYGB presented significant reduction of steatohepatitis (RD: 0.53; 95% CI 0.33 to 0.74) and fibrosis (RD: 0.26; 95% CI 0.14 to 0.37). SG caused a significant reduction of steatohepatitis (RD: 0.42; 95% CI 0.27 to 0.57), but not of fibrosis (RD: 0.20; 95% CI -0.00 to 0.39). The NAFLD Activity Score was significantly improved after both procedures, as well as biochemical tests. No difference was found between RYGB and SG regarding the histopathological outcomes. SG and RYGB are equivalently effective for treating NAFLD/NASH.

Comparison of Liver Recovery After Sleeve Gastrectomy and Roux-en-Y-Gastric Bypass

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a common condition in patients with obesity. Bariatric surgery has often been proposed as a viable treatment option, but the ideal surgical procedure remains unclear. Inconsistently, reports on postoperative deterioration of liver function put further doubt on which technique to apply. Aim of this study was to assess the impact of Roux-en-Y-gastric bypass (RYGB) and sleeve gastrectomy (SG) on the postoperative recovery of liver function.

METHODS

A total of 175 patients with obesity that underwent bariatric surgery in our institution were included in this prospective cohort study. BMI, laboratory values, and liver function capacity (using LiMAx) were assessed preoperatively and at 6 and 12 months postoperatively. Generalized linear model (GLM) was performed to determine variables influencing liver function capacity after the operation.

RESULTS

Prior to operations, 64% of patients presented with a diminished liver function capacity, as measured by LiMAx test. Liver function capacity significantly recovered after 12 months in the SG group (300 μg/kg/h preop vs. 367 μg/kg/h postop) but not in the RYGB group (306 μg/kg/h preop vs. 349 μg/kg/h). Preoperative factors impeding liver function recovery included type 2 diabetes mellitus (T2DM), weight, male sex, AST/thrombocyte ratio (APRI), and gamma-glutamyltransferase (GGT).

CONCLUSION

Bariatric surgery, especially sleeve gastrectomy, leads to an improvement of liver function. However, in some patients with T2DM, higher preoperative weight and male sex postoperative deterioration of liver function capacity may occur.

Recent advances in the mechanisms underlying the beneficial effects of bariatric and metabolic surgery

Bariatric and metabolic surgery (BMS) is the most effective treatment for obesity, type 2 diabetes and co-morbidities, including nonalcoholic fatty liver disease and nonalcoholic steatohepatitis. The beneficial effects of BMS are beyond the primary goal of gastric restriction and nutrients malabsorption. Roux-en-Y gastric bypass and vertical sleeve gastrectomy are the 2 most commonly performed procedures of BMS. Both surgeries lead to physiologic changes in gastrointestinal tract; subsequently alter bile acids pool and composition, gut microbial activities, gut hormones, and circulating exosomes; and ultimately contribute to the improved glycemic control, insulin sensitivity, lipid metabolism, energy expenditure, and weight loss. The mechanisms underlying the benefits of BMS likely involve the bile acid-signaling pathway mediated mainly by nuclear farnesoid X receptor and the membrane Takeda G protein-coupled receptor, bile acids-gut microbiota interaction, and exosomes. In this review, we focus on recent advances in potential mechanisms and aim to learn novel insights into the molecular mechanisms underlying metabolic disorders.

Microbial Adaptation Due to Gastric Bypass Surgery: The Nutritional Impact

Bariatric surgery leads to sustained weight loss and the resolution of obesity-related comorbidities. Recent studies have suggested that changes in gut microbiota are associated with the weight loss induced by bariatric surgery. Several studies have observed major changes in the microbial composition following gastric bypass surgery. However, there are inconsistencies between the reported alterations in microbial compositions in different studies. Furthermore, it is well established that diet is an important factor shaping the composition and function of intestinal microbiota. However, most studies on gastric bypass have not assessed the impact of dietary intake on the microbiome composition in general, let alone the impact of restrictive diets prior to bariatric surgery, which are recommended for reducing liver fat content and size. Thus, the relative impact of bariatric surgery on weight loss and gut microbiota remains unclear. Therefore, this review aims to provide a deeper understanding of the current knowledge of the changes in intestinal microbiota induced by bariatric surgery considering pre-surgical nutritional changes.

The advantages and disadvantages of sleeve gastrectomy; clinical laboratory to bedside review

Sleeve gastrectomy is a surgical technique and a leading method in metabolic surgery. Sleeve gastrectomy gained ever-increasing popularity among laparoscopic surgeons involved in bariatric surgery and has proved to be a successful method in achieving considerable weight loss in a short time. There are some disparate effects that patients may experience after sleeve gastrectomy including a reduction in BMI, weight, blood pressure, stroke, and cancer and also a significant remission in obesity-related diseases including type 2 diabetes (T2D), Non-alcoholic fatty liver (NAFLD), cardiovascular disease, obstructive sleep apnea, and craniopharyngioma-related hypothalamic obesity as well as non-obesity-related diseases such as gout, musculoskeletal problems, ovarian disorders and urinary incontinence. The most common complications of sleeve gastrectomy are bleeding, nutrient deficiencies, and leakage. There are several studies on the impact of gender and ethnic disparities on post-operative complications. This study collects state of the art of reports on sleeve gastrectomy. The aim of this study was to analyze recent studies and review the advantages and disadvantages of sleeve gastrectomy.