Bariatric Surgery in Nonalcoholic Fatty Liver Disease (NAFLD): Impact Assessment Using Paired Liver Biopsy and Fibroscan

Recompensation in MASLD-related cirrhosis via metabolic bariatric surgery

The prognosis of patients with decompensated cirrhosis is poor, with significantly increased liver-related mortality rates. With the rising tide of decompensated cirrhosis associated with metabolic dysfunction-associated steatotic liver disease (MASLD), the role of metabolic bariatric surgery (MBS) in achieving hepatic recompensation is garnering increasing attention. However, the complexity of preoperative assessment, the risk of postoperative disease recurrence, and the potential for patients to experience surgical complications of the MBS present challenges. In this opinion article we analyze the potential of MBS to induce recompensation in MASLD-related cirrhosis, discuss the mechanisms by which MBS may affect recompensation, and compare the characteristics of different MBS procedures; we highlight the therapeutic potential of MBS in MASLD-related cirrhosis recompensation and advocate for research in this complex area.

Asia's Growing Contribution to Obesity Surgery Research: A 40-year Bibliometric Analysis

Bariatric metabolic surgery's global research interest is growing, particularly in Asia due to its high obesity rates. This study focuses on Asia, especially China, analyzing 3904 publications (1221 from China) from 1980 to 2022. Research output accelerated until the COVID-19 pandemic, driven by economic growth and rising obesity rates. China led contributions from 2010, but Western Asia led when adjusted for population. An intra-regional research collaboration network emerged, driven by geographic proximity and similar economic environments. Keyword analysis highlighted emerging topics like "laparoscopic sleeve gastrectomy" and "non-alcoholic fatty liver disease," indicating a shift in focus. The study recommends disseminating research in top-tier journals to enhance visibility and impact.

Compare the Combined Diagnostic Accuracy of Transient Elastography and Visual Liver Score in Assessing Non-Alcoholic Fatty Liver Disease (NAFLD) and Compare it with Liver Biopsy in Morbidly Obese Patients Undergoing Bariatric Surgery: An Observational Study

INTRODUCTION

A liver biopsy is the gold standard for the diagnosis of non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH). Here, we combine preoperative transient elastography (TE) and intraoperative standardized visual liver score (VLS) which is compared with intraoperative liver biopsy for prediction of NAFLD and NASH in patients undergoing bariatric surgery.

AIM

Evaluate the combined diagnostic accuracy of TE and VLS in assessing NAFLD or NASH and compare it with liver biopsy in patients undergoing bariatric surgery.

METHODS

In a prospective cohort of 70 morbidly obese undergoing bariatric surgery, preoperative TE and intraoperative VLS were calculated. Findings of TE and VLS were compared with histology from intraoperative liver biopsy.

RESULTS

Histologically, 44 (62.85%) had NAFLD (≥ S1). Significant steatosis was seen in 20 (28.57%) while significant fibrosis was visible in 18 (25.71%). Area Under the Receiver Operating Characteristics (AUROC) TE for diagnosis of NAFLD was excellent (0.844, p = 0.001). At the optimal cutoff of 8.1, the positive predictive value (PPV) was 92.9%, and diagnostic accuracy was 90.6%. VLS had a sensitivity of 90.9% for NAFLD. The combined sensitivity of TE + VLS was 95.5% for ruling out NAFLD. Fourteen (20%) had NASH. VLS had a diagnostic accuracy of 97% in identifying NASH in comparison to TE. AUROC-VLS was 0.987, p ≤ 0.001, and a sensitivity of 100%. The overall sensitivity of combined TE and VLS was 100% with a negative predictive value (NPV) of 100%.

CONCLUSION

TE when combined with intraoperative VLS is comparable to liver biopsy and can be used for the diagnosis of NAFLD and NASH in patients undergoing bariatric surgery.

Mid-term Effects of Bariatric Surgery on Metabolic Dysfunction-Associated Fatty Liver Disease Remission and Predictive Factors: A Prospective Study with a Focus on Non-invasive Diagnosis

PURPOSE

Non-alcoholic fatty liver disease (NAFLD), now termed metabolic dysfunction-associated fatty liver disease (MAFLD), is a growing health concern associated with obesity and type 2 diabetes. Bariatric surgery offers potential benefits, but its impact on MAFLD remains incompletely understood, with scarce long-term follow-up prospective studies. Moreover, being liver biopsy the gold standard for liver condition measurement, the need for non-invasive techniques that allow the assessment of MAFLD development after bariatric surgery is imperative. OWLiver® Care and OWLiver® represent two serum lipidomic tests, featuring panels comprising 11 and 20 triglycerides, respectively.

MATERIALS AND METHODS

We conducted a prospective study involving 80 Caucasians to assess the effects of bariatric surgery on MAFLD using non-invasive diagnostics and to identify baseline predictors of MAFLD remission. Serum samples were collected before surgery and at a 3-year follow-up.

RESULTS

After 3 years, the proportion of patients exhibiting a healthy liver escalated from 5.0% at baseline to 26.3%. Conversely, the percentage of steatohepatitis declined from 35.1% to a mere 7.6%. Younger age, female gender, and the absence of type 2 diabetes were associated with MAFLD remission. However, age stood as the only independent variable associated with this favorable liver evolution (R2 = 0.112).

CONCLUSION

Bariatric surgery demonstrates mid-term benefits in improving MAFLD, with younger age as a baseline predictor of remission. Non-invasive diagnostic methods, like OWLiver®, are valuable tools for monitoring MAFLD evolution. Further research with larger populations and longer follow-up periods is warranted to refine personalized treatment approaches.

Beneficial Short-Term Effects of Bariatric Surgery on Nutritional Inflammatory Profile and Metabolic Biomarkers

PURPOSE

Bariatric surgery (BS) has several potential metabolic benefits. However, little is known about its impact on changes in the inflammatory potential of diet and its effect on inflammatory and metabolic markers. This study aimed to assess the short-term beneficial effects of BS on dietary inflammatory potential and inflammatory and metabolic markers.

MATERIALS AND METHODS

Participants (n = 20) were evaluated 3 months before and after BS. Body mass, body mass index, anthropometric measurements, fat mass, fat-free mass, visceral fat, skeletal muscle mass, basal metabolic rate, serum lipids, HOMA-IR, QUICKI and inflammatory markers, including leptin, adiponectin, adiponectin/leptin ratio and plasminogen activator inhibitor-1 (PAI-1), were evaluated. Diet data were collected using a 3-day diet record and the dietary inflammatory index (DII®) and energy-adjusted dietary inflammatory index (E-DIITM) scores were computed.

RESULTS

There was a reduction in DII® (2.56 vs 2.13) and E-DIITM (2.18 vs 0.45) indicating an improvement in inflammatory nutritional profile. Moreover, there were increases in the adiponectin/leptin ratio (0.08 vs 0.21) and QUICKI scores (0.31 vs 0.37), and reductions in leptin (36.66 vs 11.41 ng/ml) and HOMA-IR scores (3.93 vs 1.50). There were also improvements in body composition and anthropometric parameters.

CONCLUSIONS

BS promotes changes in metabolic profile, inflammatory state and food intake and these modifications appeared to be associated with improvements in diet-related inflammation, an increase in the adiponectin/leptin ratio and a reduction in leptin. These results contribute to knowledge on the contribution bariatric surgery can make to the treatment of obesity and the reduction of related comorbidities.

Impact of pre-operative weight loss on non-alcoholic fatty liver disease histopathology and insulin resistance in individuals undergoing bariatric surgery: a propensity matched cross-sectional comparison

BACKGROUND

The effect of weight loss (WL) on histopathological aspects of non-alcoholic fatty liver disease (NAFLD) may provide further insights into the dynamics of hepatic recovery after WL.

OBJECTIVE

To analyze the effects of pre-operative WL on insulin resistance- and NAFLD-related histology in individuals undergoing bariatric surgery (BS) with or without pre-operative WL.

DESIGN AND SETTING

A matched cross-sectional study was conducted at a public university hospital and a private clinic in Campinas, Brazil.

METHODS

An analytical, observational, cross-sectional study was conducted using prospectively collected databases of individuals who underwent BS and liver biopsy at either a public tertiary university hospital (with pre-operative WL) or a private clinic (without pre-operative WL). Random electronic matching by gender, age, and body mass index (BMI) was performed and two paired groups of 24 individuals each were selected.

RESULTS

Of the 48 participants, 75% were female. The mean age was 37.4 ± 9.6. The mean BMI was 38.9 ± 2.6 kg/m2. Fibrosis was the most common histopathological abnormality (91.7%). Glucose was significantly lower in the WL group (92 ± 19.1 versus 111.8 ± 35.4 mg/dL; P = 0.02). Significantly lower frequencies of macrovesicular steatosis (58.3% versus 95.8%; P = 0.004), microvesicular steatosis (12.5% versus 87.5%; P < 0.001), and portal inflammation (50% versus 87.5%; P = 0.011) were observed in the WL group.

CONCLUSION

Pre-operative WL was significantly associated with lower frequencies of macro- and mi- crovesicular steatosis, portal inflammation, and lower glycemia, indicating an association between the recent trajectory of body weight and histological aspects of NAFLD.

A review on the beneficial effects of bariatric surgery in the management of obesity

INTRODUCTION

Obesity is a chronic disease with a complex interplay of multiple factors such as genetic, metabolic, behavioral, and environmental factors. The management of obesity includes; lifestyle modification, psychological therapy, pharmacological therapy, and bariatric surgery. To date, bariatric surgery is the most effective treatment for obesity by offering a long-term reduction in weight, remission of obesity-related complications, and improving quality of life. However, bariatric surgery is not equally effective in all patients. Thus, if we can predict who would benefit most, it will improve the risk versus benefit ratio of having surgery.

AREAS COVERED

In this narrative review, we explore the question on who will benefit the most from bariatric surgery by examining the recent evidence in the literature. In addition, we investigate the predisposing predictors of bariatric surgery response. Finally, we offer the best strategies in the clinic to explain the potential benefits of bariatric surgery to patients.

EXPERT OPINION

Bariatric surgery is an effective obesity management approach. Despite its efficacy, considerable variation of individual response exists. Thus, it is important to recognize patients that will benefit most, but at present very few predictors are available which can be clinically useful.

The Effect of Roux-en-Y Gastric Bypass on Non-Alcoholic Fatty Liver Disease Fibrosis Assessed by FIB-4 and NFS Scores-An 11.6-Year Follow-Up Study

Severe obesity is a strong risk factor for non-alcoholic fatty liver disease (NAFLD). Roux-en-Y gastric bypass (RYGB) surgery effectively induces weight loss, but few studies have described the long-term effects of RYGB on NAFLD-related fibrosis. Data from 220 patients with severe obesity operated by RYGB in Central Norway were analysed. Variables incorporated in NAFLD Fibrosis Score (NFS), Fibrosis-4 (FIB-4) index and anthropometric data were collected before surgery and a mean of 11.6 years postoperatively. FIB-4 > 1.3 or NFS > 0.675 were used as cut-off values for advanced fibrosis. Proportions with advanced fibrosis decreased from 24% to 14% assessed by FIB-4 and from 8.6% to 2.3% using NFS, with resolution rates of advanced fibrosis of 42% and 73%, respectively. The shift towards lower fibrosis categories was significant (NFS p < 0.0001; FIB-4 p = 0.002). NFS decreased from −1.32 (IQR −2.33−−0.39) to −1.71 (IQR −2.49−−0.95, p < 0.001) 11.6 years after surgery, whereas FIB-4 did not change: 0.81 (IQR 0.59−1.25) to 0.89 (IQR 0.69−1.16, p = 0.556). There were weak correlations between change in fibrosis scores and weight loss. In conclusion, the majority of patients with advanced fibrosis at baseline had improvement after 11.6 years. Factors associated with reduction in fibrosis were not identified.

Endoscopic Bariatric Treatment with Duodenal-Jejunal Bypass Liner Improves Non-invasive Markers of Non-alcoholic Steatohepatitis

Purpose

People with obesity often develop non-alcoholic fatty liver disease (NAFLD) and are at high risk of progression to non-alcoholic steatohepatitis (NASH). Few therapies are effective other than bariatric surgery. We therefore analyzed data from duodenal-jejunal bypass liner (DJBL) patients regarding steatosis, fibrosis, and NASH.

Methods

Consecutive DJBL patients with type 2 diabetes underwent standardized assessments up to device removal at 48 weeks. These included aspartate and alanine transaminase (AST, ALT), controlled attenuation parameter (CAP, for steatosis), and liver stiffness measurement (LSM, for fibrosis). The NAFLD fibrosis score (NFS), fibrosis-4 score (FIB4), and enhanced liver fibrosis (ELF) test were also used to assess fibrosis and the Fibroscan-AST (FAST) score to assess NASH. Mixed models were used and missing data were accounted for with multiple imputation.

Results

Thirty-two patients (18 female, mean age 55.1, mean BMI 40.2 kg/m²) were included. After 48 weeks, the change compared to baseline with 95% CI was a factor 0.74 (0.65 to 0.84) for AST, 0.63 (0.53 to 0.75) for ALT, and a difference of − 0.21 (− 0.28 to − 0.13) for FAST, all with p < 0.001. Fibrosis based on LSM, NFS, and ELF did not change whereas FIB4 exhibited slight improvement. Eight DJBL were explanted early due to device-related complications and eight complications led to hospitalization.

Conclusions

One year of DJBL therapy is associated with relevant improvements in non-invasive markers of steatosis and NASH, but not fibrosis, and is accompanied by a substantial number of complications. Given the lack of alternatives, DJBL deserves further attention.

Graphical abstract

Bariatric Surgery Improves Nonalcoholic Fatty Liver Disease: Systematic Review and Meta-Analysis

PURPOSE

Bariatric surgery has been uncovered to relieve nonalcoholic fatty liver disease (NAFLD) in patients with obesity, while current studies have neutral or opposite results. This systematic review and meta-analysis aimed to evaluate the effects of bariatric surgery on NAFLD in patients with obesity.

MATERIALS AND METHODS

PubMed, Embase, Cochrane Central, and Web of Science databases were performed to obtain publications containing comparison results of liver biopsy before and after bariatric surgery in obesity. Primary outcomes were biopsy-confirmed remission of NAFLD and NAFLD activity scores. Secondary outcomes were liver function. This study was registered with PROSPERO, CRD42021240346.

RESULTS

Thirty-seven studies were included. After bariatric surgery, a biopsy-confirmed resolution of steatosis was improved in 56% of patients, ballooning degeneration in 49%, inflammation in 45%, and fibrosis in 25%. Bariatric surgery significantly decreased mean NAFLD activity scores. RYGB achieved the most obviously improvements in steatosis, and SG attained the most notably ameliorations in fibrosis. The percentage of patients with improved steatosis and hepatic fibrosis in Asian countries was higher than non-Asian countries. The reduction of ALT and AST was 11.95U/L and 6.44 U/L after surgery.

CONCLUSION

Our study has revealed that bariatric surgery brought out significantly resolution of NAFLD in individuals with obesity. RYGB and SG have been proved to be of benefit to many hepatic parameters, and the improvement of liver steatosis and fibrosis, particularly in Asian countries. It is strongly suggested that bariatric surgery should be considered as a novel treatment for NAFLD.

The Coexistence of Nonalcoholic Fatty Liver Disease and Type 2 Diabetes Mellitus

The incidence of nonalcoholic fatty liver disease (NAFLD) is growing worldwide. Epidemiological data suggest a strong relationship between NAFLD and T2DM. This is associated with common risk factors and pathogenesis, where obesity, insulin resistance and dyslipidemia play pivotal roles. Expanding knowledge on the coexistence of NAFLD and T2DM could not only protect against liver damage and glucotoxicity, but may also theoretically prevent the subsequent occurrence of other diseases, such as cancer and cardiovascular disorders, as well as influence morbidity and mortality rates. In everyday clinical practice, underestimation of this problem is still observed. NAFLD is not looked for in T2DM patients; on the contrary, diagnosis for glucose metabolism disturbances is usually not performed in patients with NAFLD. However, simple and cost-effective methods of detection of fatty liver in T2DM patients are still needed, especially in outpatient settings. The treatment of NAFLD, especially where it coexists with T2DM, consists mainly of lifestyle modification. It is also suggested that some drugs, including hypoglycemic agents, may be used to treat NAFLD. Therefore, the aim of this review is to detail current knowledge of NAFLD and T2DM comorbidity, its prevalence, common pathogenesis, diagnostic procedures, complications and treatment, with special attention to outpatient clinics.

Nicotinamide supplementation in diabetic nonalcoholic fatty liver disease patients: randomized controlled trial

Background:

Nicotinamide has been reported to protect against liver steatosis and metabolic imbalances in nonalcoholic fatty liver disease (NAFLD) in animal models.

Objectives:

The objective was to investigate the efficacy and safety of nicotinamide supplementation in diabetic NAFLD patients.

Design:

This is a prospective randomized controlled open label study.

Methods:

Seventy diabetic NAFLD patients were randomly assigned either to the nicotinamide group (n = 35) who received nicotinamide 1000 mg once daily for 12 weeks in addition to their antidiabetic therapy or the control group (n = 35) who received their antidiabetic therapy only. The primary outcome was improvement in steatosis score, while secondary outcomes included assessment of liver stiffness, liver enzymes, lipid profile, insulin resistance, serum malondialdehyde, serum adiponectin, and patients’ quality of life (QOL).

Results:

Only 61 patients completed the study; 31 in the nicotinamide group and 30 in the control group. Comparisons between groups and within groups revealed nonsignificant changes in steatosis and fibrosis scores. However, significant reduction was observed in liver enzymes with a median decrease in alanine transaminase of 26.6% versus 0.74% in nicotinamide and control groups, respectively. After 12 weeks of treatment, the nicotinamide group showed significantly lower levels of low-density lipoprotein cholesterol (p value = 0.004), total cholesterol (p value = 0.006), and insulin resistance marker (p value = 0.005) compared with control. Serum triglycerides, malondialdehyde, and adiponectin levels were all comparable between the two groups. Regarding QOL, a significant improvement was detected in the total scores and the activity and fatigue domains scores.

Conclusion:

Nicotinamide at a dose of 1000 mg daily was tolerable, improved metabolic abnormalities and QOL of diabetic NAFLD patients with no effect on liver fibrosis or steatosis.

Trial Registration:

The study was registered at clinicaltrials.gov and given the ID number: ‘NCT03850886’. https://clinicaltrials.gov/ct2/show/NCT03850886.

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.

Gut microbiota and related metabolites in the pathogenesis of nonalcoholic steatohepatitis and its resolution after bariatric surgery

Nonalcoholic fatty liver disease (NAFLD) is increasing in parallel with the rising prevalence of obesity, leading to major health and socioeconomic consequences. To date, the most effective therapeutic approach for NAFLD is weight loss. Accordingly, bariatric surgery (BS), which produces marked reductions in body weight, is associated with significant histopathological improvements in advanced stages of NAFLD, such as nonalcoholic steatohepatitis (NASH) and liver fibrosis. BS is also associated with substantial taxonomical and functional alterations in gut microbiota, which are believed to play a significant role in metabolic improvement after BS. Interestingly, gut microbiota and related metabolites may be implicated in the pathogenesis of NAFLD through diverse mechanisms, including specific microbiome signatures, short chain fatty acid production or the modulation of one-carbon metabolism. Moreover, emerging evidence highlights the potential association between gut microbiota changes after BS and NASH resolution. In this review, we summarize the current knowledge on the relationship between NAFLD severity and gut microbiota, as well as the role of the gut microbiome and related metabolites in NAFLD improvement after BS.

Correlation Between Sex Hormones and Non-alcoholic Fatty Liver Disease Before and After Laparoscopic Sleeve Gastrectomy

OBJECTIVES

To investigate the cross-sectional and longitudinal correlation between sex hormones and non-alcoholic fatty liver disease (NAFLD) in patients with obesity before and after laparoscopic sleeve gastrectomy (LSG).

METHODS

A total of 360 patients with obesity aged 16-48 years (170 men and 190 women) were enrolled between May 2017 and March 2021. Among them, 132 patients (55 men and 77 women) who underwent LSG had follow-up data. Anthropometric parameters, metabolic variables, and sex hormones were measured. NAFLD was assessed by FibroScan with controlled attenuation parameter (CAP) and liver stiffness measurement (LSM).

RESULTS

In the preoperative cohort, levels of CAP and LSM were significantly higher in men than women. Lower total testosterone (TT) was associated with higher CAP and LSM in men, whereas higher TT was associated with higher CAP in women. In the postoperative cohort, TT levels and NAFLD were significantly modified after LSG in both genders. Changes in TT levels at 3 months after surgery were negatively correlated with changes in CAP levels in men, and changes in TT levels at 6 months after surgery were positively correlated with changes in CAP levels in women. After adjusting possible confounders, the changes in TT levels were independently correlated with CAP variation in both genders.

CONCLUSIONS

LSG significantly modified TT levels and NAFLD in both genders. The correlation between TT levels and NAFLD at baseline as well as the changes after surgery suggested TT levels play an important role in the development and regression of NAFLD in both genders.

Utility of Fibroscan XL to assess the severity of non-alcoholic fatty liver disease in patients undergoing bariatric surgery

Significant weight loss can modify the progression of Nonalcoholic fatty liver disease (NAFLD) with the most convincing evidence coming from bariatric surgery cohorts. Effective ways to non-invasively characterise NAFLD in these patients has been lacking, with high Fibroscan failure rates reported. We prospectively evaluated the utility of Fibroscan using XL-probe over a two-year period. 190 consecutive patients undergoing bariatric surgery were followed as part of their routine care. All patients had Fibroscan performed on the day of surgery and at follow-up a mean of 13 months (± 6.3) later. The majority of patients were female (82%) with mean age of 42. Fibroscan was successful in 167 (88%) at baseline and 100% at follow up. Patients with a failed Fibroscan had higher body mass index (BMI) and alanine transaminase (ALT), but no difference in FIB-4/NAFLD score. Mean baseline Liver stiffness measurement was 5.1 kPa, with 87% of patients classified as no fibrosis and 4% as advanced fibrosis. Mean baseline controlled attenuation parameter was 291, with 78% having significant steatosis, 56% of which was moderate-severe. Significant fibrosis was associated with higher BMI and HbA1c. Significant steatosis was associated with higher BMI, ALT, triglycerides and insulin resistance. Mean follow up time was 12 months with weight loss of 25.7% and BMI reduction of 10.4 kg/m². Seventy patients had repeat fibroscan with reductions in steatosis seen in 90% and fibrosis in 67%. Sixty-four percent had complete resolution of steatosis. Fibroscan can be performed reliably in bariatric cohorts and is useful at baseline and follow-up. Significant steatosis, but not fibrosis was seen in this cohort with substantial improvements post-surgery.