Nonalcoholic fatty liver disease and bariatric surgery: a comprehensive review

NON-ALCOHOLIC FATTY LIVER DISEASE AND EXTRA-HEPATIC CANCER: A NARRATIVE REVIEW

BACKGROUND

Recently, significant associations between non-alcoholic fatty liver disease (NAFLD) and extra-hepatic cancer have been reported.

OBJECTIVE

To carry out a comprehensive review of the current evidence in the literature on the association between NAFLD and extra-hepatic cancer.

METHODS

A narrative literature review was performed through an online search for the MeSH terms "fatty liver" and "cancer" in MEDLINE (via PubMed) and LILACS (via BVS). Original studies that described the impact of NAFLD on different types of extra-hepatic malignancies were included.

RESULTS

After careful analysis, nine prospective cohort studies, one retrospective cohort study, three case-control studies, and three cross-sectional studies were selected.

CONCLUSION

There is consistent evidence on the association between NAFLD and extra-hepatic carcinogenesis, especially in relation to colorectal, gastric, pancreatic, breast, prostate, and bladder cancers.

DIAGNOSTIC ACCURACY OF THE NON-INVASIVE MARKERS NFLS, NI-NASH-DS, AND FIB-4 FOR ASSESSMENT OF DIFFERENT ASPECTS OF NON-ALCOHOLIC FATTY LIVER DISEASE IN INDIVIDUALS WITH OBESITY: CROSS-SECTIONAL STUDY

BACKGROUND

Non-invasive markers have been developed to assess the presence and severity of liver abnormalities related to non-alcoholic fatty liver disease (NAFLD).

OBJECTIVE

To analyze the diagnostic accuracy of non-invasive NAFLD markers (NAFLD liver fat score [NLFS], non-invasive non-alcoholic steatohepatitis detection score [NI-NASH-DS] and fibrosis score based on four variables [FIB-4]) in individuals with obesity undergoing bariatric surgery.

METHODS

A descriptive retrospective cross-sectional study was carried out enrolling 91 individuals who underwent bariatric surgery at a tertiary-level public university hospital. Non-invasive NAFLD markers were calculated using laboratory tests, clinical and anthropometric variables and diagnostic accuracy tests were calculated comparing them in relation to the gold-standard test for this analysis (histopathological evaluation).

RESULTS

A total of 85.7% of the participants were female and mean age was 39.1±9.8 years. The average body mass index was 38.4±3.6 kg/m2. At histopathological examination, 84 (92.3%) patients presented with steatosis, 82 (90.1%) with some type of fibrosis; 21 (23.1%) patients were diagnosed with NASH according to the NAFLD activity score criteria. The overall accuracy of NLFS score was 58.2% for general hepatic steatosis and 61.5% for moderate to severe steatosis. The overall accuracy of FIB-4 was 95.4% for advanced fibrosis. NI-NASH-DS had a 74.7% overall accuracy for NASH.

CONCLUSION

In a population of individuals with obesity, the FIB-4 score had high overall accuracy in assessing the presence of advanced liver fibrosis, whereas the NFLS and NI-NASH-DS had moderate accuracies for the assessment of steatosis and NASH, respectively.

Association of Histopathological and Biochemical Aspects of NAFLD With the Severity of Liver Fibrosis in Individuals With Obesity: Cross-sectional Study

BACKGROUND

Given the importance of fibrosis in the progression of non-alcoholic fatty liver disease (NAFLD), identifying biochemical and histopathological aspects associated with its severity is important to determine the course of disease in high-risk populations.

OBJECTIVES

The study aims to investigate correlations between biochemical and histopathological variables associated with the occurrence and severity of NAFLD-related liver fibrosis in individuals with obesity.

METHODS

This is a cross-sectional study which enrolled 171 individuals who underwent bariatric surgery at a tertiary university hospital. Clinical, laboratory, and histopathological hepatic characteristics were analyzed. Univariate and multivariate analyses were carried out to identify factors associated with the outcomes studied (severity of fibrosis staging) through simple and multiple regression models.

RESULTS

Female were 87.7%, and the mean age was 38.4 ± 9.3 years. The most common histopathological abnormalities were macrovesicular steatosis (74.9%) and hepatocellular ballooning (40.4%). In the histopathological univariate analysis, liver fibrosis significantly correlated with severities of microvesicular steatosis (p = 0.003), lobular inflammation (p = 0.001), and NAS (p < 0.001). In the multivariate analysis, the degrees of microvesicular steatosis (p < 0.001) and NAS (p < 0.001) independently correlated with fibrosis severity. In the univariate biochemical analysis, fibrosis severity significantly correlated with levels of hemoglobin A1c (p = 0.004) and glucose (p = 0.01). In the multivariate analysis, glucose levels independently correlated with liver fibrosis degree (p = 0.007).

CONCLUSION

Significant and independent associations were observed between the intensities of microvesicular steatosis, NAS, and glucose levels and the severity degree of liver fibrosis in individuals with obesity.

Fibrotic NASH in Individuals with Obesity: a Cross-sectional Analysis of the Prevalence of this Significant Milestone of Disease Progression and Accuracy of a Non-invasive Marker for its Screening

BACKGROUND

Fibrotic non-alcoholic steatohepatitis (NASH), i.e., the concomitant presence of active inflammation and fibrosis, represents a milestone in the natural history of NAFLD and a critical time point in its progression. The purpose of this study was to analyze the diagnostic accuracy of the non-invasive Fibrotic NASH Index (FNI) in individuals with obesity undergoing bariatric surgery.

METHODS

This is a cross-sectional study, enrolling individuals who underwent bariatric surgery with liver biopsy at a tertiary university hospital. FNI was calculated, and a cutoff value was determined. Its diagnostic accuracy was then calculated through comparison with the gold standard test for this analysis (histopathological examination).

RESULTS

Of 128 participants, 83.6% were female, and the average age was 39.8 ± 8.7 years. The mean BMI was 38.7 ± 5.7 kg/m2. NAFLD was histologically confirmed in 76.6%, of which 81.6% had NASH. Histologically confirmed fibrotic NASH was observed in 22.7% of the general study population, 29.6% of individuals with NAFLD, and 36.3% of those with NASH. The mean FNI was 0.18 ± 0.19. An optimal cutoff point of 0.21 was determined, with an overall accuracy of 90.1%, an 82.8% sensitivity, a 90.8% specificity, a 72.6% positive predictive value, and a 94.7% negative predictive value.

CONCLUSIONS

FNI provided adequate accuracy in detecting and ruling out fibrotic NASH. Considering the importance of fibrotic NASH within the natural history of NAFLD progression and the fact that this marker uses simple variables, it may be of great importance in high-risk populations, and its external validation and use should be encouraged.

Identification of Predictors of Non-alcoholic Steatohepatitis and Its Severity in Individuals Undergoing Bariatric Surgery

BACKGROUND

As obesity reached epidemic proportions, non-alcoholic fatty liver disease (NAFLD) also had a worrisome parallel increase. The non-invasive differentiation of non-alcoholic steatohepatitis (NASH) from uncomplicated NAFLD remains an important challenge in current clinical practice.

OBJECTIVE

To identify predictors of the occurrence and severity of NAFLD and NASH.

METHODS

This is an analytical cross-sectional study which included individuals undergoing bariatric surgery. Participants were histologically classified according to the presence NASH and severity of NAFLD. Demographic, clinical, anthropometric, and biochemical aspects were analyzed and compared.

RESULTS

Out of 171 individuals, 87.7% were female and the mean age was 38.4±9.3 years. The average BMI was 38±3.0 kg/m2. NAFLD was histologically confirmed in 74.9%; the commonest histopathological abnormalities were macrovesicular steatosis (74.9%) and ballooning (40.4%). Simple steatosis occurred in 30.4%, 44.4% presented with NASH, and 31% had severe NAFLD. NASH associated with higher levels of ALT (0.03), ALP (0.02), and glucose (0.02). Cutoff values were, respectively, 23 U/L, 67 U/L, and 81 mg/dL. Their concomitant use provided an 83.1% specificity for NASH. Severe NAFLD associated with diabetes (p=0.02), higher BMI (p=0.01), AST (p=0.04), ALT (p<0.01), ALP (p=0.01), glucose (p=0.02), and ferritin (p<0.01). BMI over 39.3 kg/m2 and ferritin over 178 ng/mL concomitantly provided a 70.5% accuracy for severe NAFLD.

CONCLUSIONS

NASH and severe NAFLD associated with higher levels of ALT, ALP, and glucose. Severe NAFLD associated with higher BMI and higher ferritin levels in this group. The concomitant evaluation of these laboratory tests could help ruling out NASH and safely screening severe NAFLD.

GLP-1/GLP-1RAs: New Options for the Drug Treatment of NAFLD

Non-alcoholic fatty liver disease (NAFLD) has recently emerged as a global public health concern. Currently, the cornerstone of NAFLD treatment is lifestyle modification and, if necessary, weight loss. However, compliance is a challenge, and this approach alone may not be sufficient to halt and treat the more serious disease development, so medication is urgently needed. Nevertheless, no medicines are approved to treat NAFLD. Glucagon-like peptide-1 (GLP-1) is an enteropeptide hormone that inhibits glucagon synthesis, promotes insulin secretion, and delays gastric emptying. GLP-1 has been found in recent studies to be beneficial for the management of NAFLD, and the marketed GLP-1 agonist drugs have different degrees of effectiveness for NAFLD while lowering blood glucose. In this article, we review GLP-1 and its physiological roles, the pathogenesis of NAFLD, the correlation between NAFLD and GLP-1 signaling, and potential strategies for GLP-1 treatment of NAFLD.

The Use of Noninvasive Scores in Predicting NAFLD Progression After Bariatric Surgery

BACKGROUND

Bariatric surgery has been postulated to impact liver function resulting in favorable effects on nonalcoholic fatty liver disease (NAFLD). We aimed to analyze the long-term impact of bariatric surgery on noninvasive scores predicting the progression of liver fibrosis in a bariatric population.

METHODS

We retrospectively reviewed the records of patients without pre-existing liver disease who underwent sleeve gastrectomy or Roux-en-Y gastric bypass (RYGB) at our center between 2010 and 2018. Four predictive scores for liver fibrosis (AST/ALT, APRI, Fib-4, and BARD) were calculated preoperatively, 6 months post-operatively, and annually up to 5 years. Correlations were analyzed with Pearson R. Subgroup and sensitivity analyses were performed to identify populations at increased risk.

RESULTS

A total of 2769 patients were included. The mean age was 40 years, and the majority was females (88.5%) and of Hispanic ethnicity (59.2%). There was a steady post-operative increase in the percentage of patients at increased risk of progression of liver fibrosis. The Fib-4 score showed the largest increase in the population at risk for liver fibrosis (11.3% preoperatively to 28.9% at 5 years). Patients with diabetes and those who underwent a sleeve gastrectomy continued to display a higher risk for liver fibrosis than did patients without diabetes and those who underwent RYGB, respectively.

CONCLUSION

There was an overall trend to increased liver fibrosis scores over the 5-year post-operative follow-up, but this increase remained lower than that reported in previous literature. Bariatric surgery offers NAFLD risk reduction in a high-risk population.

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.

Microvesicular Steatosis in Individuals with Obesity: a Histological Marker of Non-alcoholic Fatty Liver Disease Severity

BACKGROUND

In non-alcoholic fatty liver disease (NAFLD), steatosis can manifest through two distinct forms: macrovesicular (macroS) and microvesicular (microS).

OBJECTIVE

To investigate the prevalence of microS and its association with biochemical parameters and NAFLD-related histological findings in individuals with obesity.

METHODS

This is an observational retrospective cross-sectional study, enrolling individuals who underwent bariatric surgery and liver biopsy at a university hospital. A 1:2 propensity matching was performed to pair microS with isolated macroS; this matching enrolled variables "age," "gender," "body mass index (BMI)," and "obesity-associated medical problems." Clinical, biochemical, and histopathological aspects were then analyzed and compared.

RESULTS

Of 115 participants, 88.7% were female; average age was 40.5 ± 5 years and mean BMI was 37.9 ± 3.3 kg/m². Steatosis occurred in 82.6% (67.8% isolated macroS and 14.8% microS). MicroS is significantly associated with higher levels of alanine aminotransferase (ALT) (39.8 ± 26.4 vs. 26.7 ± 17.5; p = 0.04) and glucose (103.8 ± 52.6 vs. 83.3 ± 10.8; p = 0.03) and higher frequencies of moderate to severe macroS (41.2% vs. 2.0%; p < 0.001), portal fibrosis (100% vs. 50%; p < 0.001), perisinusoidal fibrosis (100% vs. 55.9%; p < 0.001), lobular inflammation (100% vs. 41.1%; p < 0.001), and portal inflammation (100% vs. 41.1%; p < 0.001). An independently positive association was observed between intensities of microS and macroS (p < 0.001).

CONCLUSION

MicroS is significantly associated with higher levels of ALT and glucose and higher frequencies of moderate to severe macroS, hepatocellular ballooning, portal fibrosis, perisinusoidal fibrosis, lobular inflammation, and portal inflammation. These findings indicate that microS could be considered a reliable histological marker of NAFLD severity.

Reliability of Non-invasive Liver Fibrosis Assessment Tools Versus Biopsy in Pre- and Post-bariatric Surgery Patients with Non-alcoholic Fatty Liver Disease

PURPOSE

Liver biopsy (LBx) remains the gold standard to assess fibrosis in non-alcoholic fatty liver disease (NAFLD). Biochemical markers are also useful, but their reliability is not clear in patients with morbid obesity. We assessed the performance of six non-invasive fibrosis assessment tools before and after bariatric surgery (BSx) using LBx.

MATERIALS AND METHODS

This is a cross-sectional and prospective cohort study. LBx was performed at the time of BSx and 12-month post-operatively and assessed using the Brunt system. Clinical and biochemical measurements were collected at the same time points and six non-invasive fibrosis assessment tools were calculated.

RESULTS

One hundred seventy patients had BSx; 79.4% female; age was 46.6 ± 9.8 years, and BMI was 48.6 ± 7.5 kg/m². From liver histology, 88% had F0-F2 and 11.2% F3-F4. At BSx, aspartate aminotransferase to platelet ratio index (APRI) and FIB-4 had better accuracy (0.86 and 0.88) with specificity of 96.6% and 94.0% and negative predictive values (NPV) of 88.9% and 93.7%. However, sensitivity (6.7% and 40.0%) and positive predictive values (PPV) (20.0% and 46.2%) were low. Twelve months post-surgery (n = 54), 88.9% of patients had F0-F2 and 11.1% had F3-F4. Fibrosis-4 index (FIB-4) and NAFLD fibrosis score (NFS) had the best accuracy (0.79 and 0.77) with specificity of 83.7% and 86.9% and NPV of 92.3% and 86.9%. However, sensitivity (25% and 0%) and PPV (12.5% and 0%) were low.

CONCLUSION

Overall, FIB-4, APRI, and NFS showed similar performances with higher accuracy, specificity, and NPV. Sensitivity and PPV were low. These tests are more useful at excluding advanced fibrosis.

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.

Trajectory of NAFLD characteristics after Roux-en-Y gastric bypass: a five-year historical cohort study

BACKGROUND

The long-term effects of bariatric surgery on the course of non-alcoholic fatty hepatopathy (NAFLD) are not fully understood.

OBJECTIVE

To analyze the evolution of NAFLD characteristics through noninvasive markers after Roux-en-Y gastric bypass (RYGB) over a five-year period.

DESIGN AND SETTING

Historical cohort study; tertiary-level university hospital.

METHODS

The evolution of NAFLD-related characteristics was evaluated among 49 individuals who underwent RYGB, with a five-year follow-up. Steatosis was evaluated through the hepatic steatosis index (HSI), steatohepatitis through the clinical score for non-alcoholic steatohepatitis (C-NASH) and fibrosis through the NAFLD fibrosis score (NFS).

RESULTS

91.8% of the individuals were female. The mean age was 38.3 ± 10 years and average body mass index (BMI), 37.4 ± 2.3 kg/m2. HSI significantly decreased from 47.15 ± 4.27 to 36.03 ± 3.72 at 12 months (P &lt; 0.01), without other significant changes up to 60 months. C-NASH significantly decreased from 0.75 ± 1.25 to 0.29 ± 0.7 at 12 months (P &lt; 0.01), without other significant changes up to 60 months. NFS decreased from 1.14 ± 1.23 to 0.27 ± 0.99 at 12 months (P &lt; 0.01), and then followed a slightly ascending course, with a marked increase by 60 months (0.82 ± 0.89), but still lower than at baseline (P &lt; 0.05). HSI variation strongly correlated with the five-year percentage total weight loss (R = 0.8; P &lt; 0.0001).

CONCLUSION

RYGB led to significant improvement of steatosis, steatohepatitis and fibrosis after five years. Fibrosis was the most refractory abnormality, with a slightly ascending trend after two years. Steatosis improvement directly correlated with weight loss.

An Unusual Long-Term Complication of Bariatric Surgery

Roux-en-Y gastric bypass (RNYGB) has become the standard of care in treating obesity, a global health concern with associated comorbidities contributing to rising health care costs [1]. The positive outcomes of RNYGB have been well documented along with adverse effects such as nutrient deficiencies, hernia, postprandial dumping syndrome, chronic kidney disease and hypoglycemia. A lesser-known long term complication of RNYGB is liver failure. Here, we present a case where RNYGB performed 10 years prior contributed to acute liver failure.

Real-world Comorbidity Burden, Health Care Utilization, and Costs of Nonalcoholic Steatohepatitis Patients With Advanced Liver Diseases

GOALS

This study evaluates the real-world comorbidity burden, health care resource utilization (HRU), and costs among nonalcoholic fatty liver disease/nonalcoholic steatohepatitis (NAFLD/NASH) patients with advanced liver diseases [compensated cirrhosis (CC), decompensated cirrhosis (DCC), liver transplantation (LT), hepatocellular carcinoma (HCC)].

BACKGROUND

NAFLD/NASH is a leading cause of liver diseases.

MATERIALS AND METHODS

Adult NAFLD/NASH patients were identified retrospectively from MarketScan Commercial claims (2006-2016). Following initial NAFLD/NASH diagnosis, advanced liver diseases were identified using the first diagnosis as their index date. Mean annual all-cause HRU and costs (2016 USD) were reported. Adjusted costs were estimated through generalized linear models. Cumulative costs were illustrated for patient subsets with variable follow-up for each stage.

RESULTS

Within the database, 485,774 NAFLD/NASH patients met eligibility criteria. Of these, 93.4% (453,564) were NAFLD/NASH patients without advanced liver diseases, 1.6% (7665) with CC, 3.3% (15,833) with DCC, 0.1% (696) with LT, and 0.1% (428) with HCC. Comorbidity burden was high and increased as patients progressed through liver disease severity stages. Compared with NAFLD/NASH without advanced liver diseases (adjusted costs: $23,860), the annual cost of CC, DCC, LT, and HCC were 1.22, 5.64, 8.27, and 4.09 times higher [adjusted costs: $29,078, $134,448, $197,392, and $97,563 (P<0.0001)]. Inpatient admissions significantly drove increasing HRU.

CONCLUSION

Study findings suggest the need for early identification and effective management of NAFLD/NASH patients to minimize comorbidity burden, HRU, and costs in the privately insured US population.

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.

Target Therapies for NASH/NAFLD: From the Molecular Aspect to the Pharmacological and Surgical Alternatives

Non-alcoholic fatty liver disease represents an increasing cause of chronic hepatic disease in recent years. This condition usually arises in patients with multiple comorbidities, the so-called metabolic syndrome. The therapeutic options are multiple, ranging from lifestyle modifications, pharmacological options, to liver transplantation in selected cases. The choice of the most beneficial one and their interactions can be challenging. It is mandatory to stratify the patients according to the severity of their disease to tailor the available treatments. In our contribution, we review the most recent pharmacological target therapies, the role of bariatric surgery, and the impact of liver transplantation on the NAFLD outcome.

Metabolic Dysfunction-Associated Fatty Liver Disease (MAFLD)-A Condition Associated with Heightened Sympathetic Activation

Metabolic dysfunction-associated fatty liver disease (MAFLD) is the most common liver disease affecting a quarter of the global population and is often associated with adverse health outcomes. The increasing prevalence of MAFLD occurs in parallel to that of metabolic syndrome (MetS), which in fact plays a major role in driving the perturbations of cardiometabolic homeostasis. However, the mechanisms underpinning the pathogenesis of MAFLD are incompletely understood. Compelling evidence from animal and human studies suggest that heightened activation of the sympathetic nervous system is a key contributor to the development of MAFLD. Indeed, common treatment strategies for metabolic diseases such as diet and exercise to induce weight loss have been shown to exert their beneficial effects at least in part through the associated sympathetic inhibition. Furthermore, pharmacological and device-based approaches to reduce sympathetic activation have been demonstrated to improve the metabolic alterations frequently present in patients with obesity, MetSand diabetes. Currently available evidence, while still limited, suggests that sympathetic activation is of specific relevance in the pathogenesis of MAFLD and consequentially may offer an attractive therapeutic target to attenuate the adverse outcomes associated with MAFLD.

Phase angle and non-alcoholic fatty liver disease before and after bariatric surgery

BACKGROUND

Obesity is a global health problem that is continuing to increase in the young population. In Brazil, the frequency of obesity in 2018 was 19.8%. Several comorbidities are directly associated with obesity, such as non-alcoholic fatty liver disease (NAFLD), which is considered the most common liver disorder in Western countries and affects up to 46% of adults. Bariatric surgery is effective in treating obesity and can improve NAFLD; however, the effect of bariatric surgery on body composition, phase angle (PA), and improving NAFLD needs to be further studied.

AIM

To analyze the PA in the postoperative period of bariatric surgery and to correlate it with changes in body composition and liver disease.

METHODS

This study is a retrospective cohort study of the analysis of the medical records of patients undergoing bariatric surgery in a reference center of a teaching hospital in Porto Alegre over a 2-year period. Patients older than 18 years whose record contained all information relevant to the study were included. The data analyzed were body composition and PA through electrical bioimpedance and NAFLD through liver biopsy in the pre- and postoperative period. The level of significance adopted for the statistical analyses was 5%.

RESULTS

We evaluated 379 patients with preoperative data. Regarding PA, 169 patients were analyzed, and 33 patients had liver biopsy pre- and postoperatively with NAFLD information. In total, 79.4% were female, with a mean age of 39.1 ± 10.6 years. The average body mass index (BMI) was 45.9 ± 7.5 kg/m². The PA showed a mean of 5.8 ± 0.62° in the preoperative period and a significant reduction in the postoperative period. A postoperative reduction in body composition data (skeletal muscle mass, fat percentage, fat mass, body cell mass, BMI and visceral fat area) was shown as well. Regarding liver disease, all patients presented a reduction in the degrees and stages of liver disease in the postoperative period, and some had no degree of liver disease at all.

CONCLUSION

PA decreased after bariatric surgery, with a direct correlation with weight loss and changes in body composition. The decrease in PA was not correlated with the improvement in NAFLD.

Is Laparoscopic Roux-en-Y Gastric Bypass Still the Gold Standard Procedure for Indians? Mid- to Long-Term Outcomes from a Tertiary Care Center

PURPOSE

Laparoscopic Roux-en-Y gastric bypass (RYGB) is the oldest and most widely performed bariatric surgery worldwide. There is, however, a scarcity of mid- to long-term data of RYGB, especially from the Indian subcontinent.

MATERIALS AND METHODS

The study was a single-center, retrospective analysis from patients who underwent RYGB between January 2009 and November 2014 from a tertiary care center in India. Percent of total weight loss (%TWL) was taken as the primary outcome of the study. Secondary outcomes included type 2 diabetes mellitus (T2DM) remission, comorbidity resolution, revisional surgeries, and complications related to RYGB at 1 year, at 3 years, and during the long term, following surgery. Postoperative visits took place at 1 and 3 years, while the long-term outcome was at median 8.3 years (range 5.4-11.2 years), with a follow-up of 92.4% (488/528), 80.5% (424/527) and 69.5% (363/522), respectively.

RESULTS

Out of 528 patients studied, 56% were females. The mean body mass index (BMI) was 40.6 ± 6.9 kg/m². The %TWL in the long-term follow-up was 21.8 ± 11.3%. T2DM remission rates at 1 year, at 3 years, and during the long term were 84.5%, 70.0%, and 60.0%, respectively. Preoperative HBA1c (p = 0.002) and insulin usage (p = 0.016) had a significant predictive effect on T2DM remission. Gastroesophageal reflux disease (GERD) improved significantly (p < 0.001). Early (< 30 days) and late (> 30 days) complications were observed in 2.3% and 4.3% of the patients, respectively.

CONCLUSION

Weight loss during mid to long-term follow-up was maintained in the majority of the patients after RYGB. However, a small proportion had significant weight regain in the long term. T2DM, GERD, and other comorbidities were well improved after RYGB.

The Prevalence of NAFLD and Fibrosis in Bariatric Surgery Patients and the Reliability of Noninvasive Diagnostic Methods

Background

Bariatric surgery patients have a higher prevalence of nonalcoholic fatty liver (NAFL) than the general population; however, its assessment and the accurate staging of fibrosis are often complicated because noninvasive tests are not very accurate in patients with morbid obesity, and liver biopsy cannot be performed as a routine exam. The aim of this study was to evaluate (A) the histological prevalence of NAFL, nonalcoholic steatohepatitis (NASH), and fibrosis in patients undergoing bariatric surgery; (B) the reliability of ultrasound (US) in diagnosing NAFL; and (C) the reliability of various fibrosis scoring systems for defining fibrosis.

Methods

US and intraoperative liver biopsy results were reviewed in 57 bariatric surgery patients. NAFL, NASH, and fibrosis were diagnosed according to the Kleiner scoring system. US diagnosis of liver steatosis was based on the bright liver. Fibrosis scores used were (i) the BMI, AST/ALT Ratio, Diabetes (BARD) scoring system; (ii) the nonalcoholic fatty liver disease (NAFLD) fibrosis score; and (iii) the fibrosis-4 (FIB-4) index.

Results

The prevalence of NAFL was 81%, NASH 61.4%, and fibrosis 94% (F3 5.7%, cirrhosis 2.8%). The sensitivity of US was 95%, specificity 50%, and likelihood ratio (LR+, LR-) 1.91 and 0.1. The reliability of fibrosis scores for F ≥ 2 were as follows: BARD score: sensitivity 46%, specificity 54%, and area under the receiver-operating characteristics (AUROC) curve 0.5; NAFLD score: sensitivity 30%, specificity 89%, and AUROC 0.5; and FIB-4: sensitivity 68%, specificity 67%, and AUROC 0.7.

Conclusions

In bariatric surgery patients, the prevalence of NAFL was 81%, NASH 61.4%, and fibrosis 94%. US is able to rule out the presence of NAFL, while the commonly used scores may be inaccurate in defining fibrosis in patients with morbid obesity.

Impact of weight trajectory after bariatric surgery on co-morbidity evolution and burden

Background

Bariatric surgery, such as Roux-en-Y gastric bypass [RYGB] has been shown to be an effective intervention for weight management in select patients. After surgery, different patients respond differently even to the same surgery and have differing weight-change trajectories. The present analysis explores how improving a patient’s post-surgical weight change could impact co-morbidity prevalence, treatment and associated costs in the Canadian setting.

Methods

Published data were used to derive statistical models to predict weight loss and co-morbidity evolution after RYGB. Burden in the form of patient-years of co-morbidity treatment and associated costs was estimated for a 100-patient cohort on one of 6 weight trajectories, and for real-world simulations of mixed patient cohorts where patients experience multiple weight loss outcomes over a 10-year time horizon after RYGB surgery. Costs (2018 Canadian dollars) were considered from the Canadian public payer perspective for diabetes, hypertension and dyslipidaemia. Robustness of results was assessed using probabilistic sensitivity analyses using the R language.

Results

Models fitted to patient data for total weight loss and co-morbidity evolution (resolution and new onset) demonstrated good fitting. Improvement of 100 patients from the worst to the best weight loss trajectory was associated with a 50% reduction in 10-year co-morbidity treatment costs, decreasing to a 27% reduction for an intermediate improvement. Results applied to mixed trajectory cohorts revealed that broad improvements by one trajectory group for all patients were associated with 602, 1710 and 966 patient-years of treatment of type 2 diabetes, hypertension and dyslipidaemia respectively in Ontario, the province of highest RYGB volume, corresponding to a cost difference of $3.9 million.

Conclusions

Post-surgical weight trajectory, even for patients receiving the same surgery, can have a considerable impact on subsequent co-morbidity burden. Given the potential for alleviated burden associated with improving patient trajectory after RYGB, health care systems may wish to consider investments based on local needs and available resources to ensure that more patients achieve a good long-term weight trajectory.

Impact of Weight Regain on the Evolution of Non-alcoholic Fatty Liver Disease After Roux-en-Y Gastric Bypass: a 3-Year Follow-up

BACKGROUND

The influence of post-surgical weight regain on the course of non-alcoholic fatty liver disease (NAFLD) is unclear.

OBJECTIVE

To evaluate the influence of weight regain on the NAFLD assessed by means of a non-invasive score after Roux-en-gastric bypass (RYGB) over a 3-year period.

METHODS

This is a prospective observational cohort study which evaluated individuals who underwent RYGB. Comparisons were made between the periods immediately before surgery and 12, 24, and 36 months following surgery. Liver disease was estimated by means of the NAFLD fibrosis score. Individuals were classified into three categories according to weight regain status: (1) no weight regain, (2) expected weight regain (regain less or equal than 20% of the maximal weight lost), (3) obesity recidivism (regain above 20% of the maximal weight lost).

RESULTS

Of 90 patients analyzed after 3 years of surgery, 35.6% presented obesity recidivism and 28.8% of the expected regain; 35.6% presented no regain. There was no difference in baseline fibrosis score between groups; at 3 years, the score observed in the relapse group was significantly higher than that observed in the other two groups (p = 0.015). The percent variation of the fibrosis score was significantly higher in the recidivism group (+ 11.8 ± 77.2%) than in the expected regain (- 45.6 ± 64.5%) and no regain (- 37.8 ± 63.2%) groups (p = 0.013).

CONCLUSION

Long-term significant post-RYGB weight regain is associated with a significantly attenuated improvement of NAFLD evaluated by means of liver fibrosis score.

Non-Alcoholic Fatty Liver Disease Is Associated with Impairment of Ejection Fraction Among Individuals with Obesity Undergoing Bariatric Surgery: Results of a Cross-Sectional Study

BACKGROUND

The relationship between non-alcoholic fatty liver disease (NAFLD) and myocardial function seems to be more than just the effect of mutual metabolic risk factors.

OBJECTIVE

To determine whether there is a significant association between NAFLD assessed by means of liver biopsy and left ventricular function expressed by the estimated ejection fraction among individuals with obesity.

METHODS

This is a cross-sectional study which enrolled individuals who consecutively underwent bariatric surgery. NAFLD was assessed by means of liver biopsies which were systematically collected during the procedures. The estimated ejection fraction was obtained by means of transthoracic echocardiograms. The main outcome evaluated was a possible association between NAFLD features and ejection fraction. The results of liver biopsies and the respective degrees of severity of each NAFLD feature were also correlated with the ejection fraction and main anthropometric, biochemical, and clinical variables.

RESULTS

Of 112 individuals, 86.6% were female and the mean age was 38.5 ± 9.3 years. It was observed that the average estimated ejection fraction (EEF) was significantly lower among individuals with liver fibrosis (67.6 ± 5.5% vs. 70.8 ± 4.9%, p = 0.008). After adjustment for confounding variables in a multivariate model, the degree of liver fibrosis was independently associated with the EEF (R = - 0.3, p = 0.02).

CONCLUSION

Among individuals with morbid obesity, the findings of this study are suggestive that liver fibrosis confirmed by histopathological examination is associated with a slight impairment of left ventricular function. Further studies are needed to confirm this association.

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.

Biliverdin reductase and bilirubin in hepatic disease

The buildup of fat in the liver (hepatic steatosis) is the first step in a series of incidents that may drive hepatic disease. Obesity is the leading cause of nonalcoholic fatty liver disease (NAFLD), in which hepatic steatosis progresses to liver disease. Chronic alcohol exposure also induces fat accumulation in the liver and shares numerous similarities to obesity-induced NAFLD. Regardless of whether hepatic steatosis is due to obesity or long-term alcohol use, it still may lead to hepatic fibrosis, cirrhosis, or possibly hepatocellular carcinoma. The antioxidant bilirubin and the enzyme that generates it, biliverdin reductase A (BVRA), are components of the heme catabolic pathway that have been shown to reduce hepatic steatosis. This review discusses the roles for bilirubin and BVRA in the prevention of steatosis, their functions in the later stages of liver disease, and their potential therapeutic application.