The evolution of severe steatosis after bariatric surgery is related to insulin resistance

Myosteatosis Predicts Bariatric Surgery Response: A Longitudinal Study in Patients With Morbid Obesity

CONTEXT

Data on the preoperative factors for bariatric surgery response in patients with morbid obesity are limited, and there are no studies on the relationship between myosteatosis and surgery response.

OBJECT

We investigated the preoperative factors determining bariatric surgery response and the impact of preoperative muscle fat infiltration on bariatric surgery response.

METHODS

This retrospective longitudinal cohort study included 125 individuals (37 men, 88 women) with morbid obesity who underwent bariatric surgery. Muscle fat infiltration [skeletal muscle fat index (SMFI)] was evaluated using computed tomography-based psoas muscle mass and density at the fourth lumbar level. A bariatric surgery response was defined as ≥50% excessive weight loss at 1 year postoperatively.

RESULTS

Before bariatric surgery, the patient's mean body weight and body mass index (BMI) were 107.0 kg and 39.0 kg/m2, respectively. After 1 year, the mean body weight was 79.6 kg. The mean excessive weight loss at 1 year was 75.6%, and 102 (81.6%) patients were categorized as responders. There were no statistically significant differences in initial BMI, age, sex, or proportion of diabetes between responders and nonresponders. Responders were more likely to have lower SMFI and triglyceride and glycated hemoglobin A1c levels than nonresponders at baseline (P < .05). Multiple logistic regression analysis showed that a lower baseline SMFI was associated with bariatric surgery response (odds ratio = 0.31, 95% confidence interval = 0.14-0.69, P = .004).

CONCLUSION

Preoperative myosteatosis may determine the response to bariatric surgery.

Three-Dimensional Vector MR Elastography for Evaluating Tissue Mechanical Heterogeneity to Assess Liver Disease Progression

Background Metabolic dysfunction-associated steatotic liver disease (MASLD) is a growing global health challenge, with evidence indicating that hepatic inflammation and fibrosis are heterogeneous processes. Purpose To measure liver mechanical property heterogeneity using MR elastography (MRE) and evaluate its potential as a biomarker for tissue inflammation and fibrosis in patients with MASLD. Materials and Methods Mechanical tissue heterogeneity in MASLD was assessed at three-dimensional vector MRE pixel-wise histogram analysis of shear stiffness and loss modulus in preclinical and clinical studies. The preclinical study involved 25 rats that were examined monthly, whereas the clinical study analyzed data from 179 participants across two prospective studies (September 2015 to November 2022), including some who underwent bariatric surgery at pretreatment and posttreatment MRE examinations. Mean and coefficient of variation (CV) of shear stiffness and loss modulus were calculated for each examination. Nonparametric tests and Spearman correlation coefficient were used to compare MRE-derived tissue mechanics with biopsy-confirmed fibrosis and inflammation and assess correlations with portal pressure and histopathologic hepatic fibrosis. Results The preclinical study showed that, in cirrhotic livers, CV of loss modulus positively correlated with portal pressure and fibrosis area ratio variation (ρ = 0.52 [P = .008] and 0.55 [P = .005], respectively). The clinical study showed that, in 10 healthy volunteers (median age, 36.5 years; IQR, 34.0-38.8 years; five females) and 169 participants with MASLD (median age, 50.1 years; IQR, 41.0-58.2 years; 118 females), CV of sheer stiffness (from 0.12 to 0.30 in healthy participants to participants with stage 4 fibrosis) and loss modulus (from 0.31 to 0.51 in healthy participants to participants with grade 3 inflammation) increased with increasing severity of fibrosis and inflammation, respectively. In 36 participants who underwent bariatric surgery, the CV of sheer stiffness decreased at the 1-year follow-up, from 0.16 (IQR, 0.14-0.18) to 0.14 (IQR, 0.12-0.16) (P = .009). Conclusion Tissue mechanical heterogeneity assessed at MRE positively correlated with progression of MASLD, demonstrating potential as a biomarker for liver disease severity and therapeutic intervention. ClinicalTrials.gov Identifier: NCT02565446 Published under a CC BY 4.0 license. Supplemental material is available for this article. See also the editorial by Moura Cunha in this issue.

The Triad of Risk: Linking MASLD, Cardiovascular Disease and Type 2 Diabetes; From Pathophysiology to Treatment

Metabolic dysfunction-associated steatotic liver disease (MASLD) is an emerging global health concern, and it is not only the keystone precursor of eventual liver-related morbidity, but it also places patients at considerably higher cardiovascular risk, which is still a leading cause of death in these patients. The most important common underlying pathophysiological mechanisms in these diseases are primarily related to insulin resistance, chronic inflammation and oxidative stress. The presence of MASLD with cardiovascular disease (CVD) and type 2 diabetes mellitus (T2DM) elevates the risk for poor outcomes, thus this review highlights a method to the therapeutic approaches. Given the intertwined nature of MASLD, T2DM, and CVD, there is an urgent need for therapeutic strategies that address all three conditions. Although lifestyle changes are important as treatment, medication plays a crucial role in managing hyperglycemia, enhancing liver function and lowering cardiovascular risk. The onset and progression of MASLD should be addressed through a multifaceted therapeutic approach, targeting inflammatory, immune, metabolic, oxidative stress, hormonal and gutaxis pathways, alongside the treatment strategies for T2DM. In this review, we discuss the effects of antidiabetic drugs with an impact on both liver outcomes and cardiovascular risk in patients affected by MASLD, T2DM and CDV.

Bariatric surgery reduces long-term mortality in patients with metabolic dysfunction-associated steatotic liver disease and cirrhosis

BACKGROUND/AIMS

With the obesity pandemic, metabolic dysfunction-associated steatotic liver disease (MASLD) is the most common liver disease and a leading cause of end-stage liver disease and liver-related deaths in the USA. Therefore, we aimed to compare the long-term outcomes of patients with MASLD and cirrhosis with and without bariatric surgery.

METHODS

Patients were retrospectively identified from the California Department of Healthcare Access and Information database, 2005 to 2019, for a population-based cohort study. Propensity score matching (PSM) was used to balance background risks between patients with cirrhosis who underwent bariatric surgery and those who did not. Overall, liver-related and non-liver-related mortality were analyzed.

RESULTS

Of 91,708 eligible patients with MASLD and cirrhosis, PSM yielded 2,107 patients who underwent bariatric surgery and 8,428 non-bariatric controls. Compared to matched controls, patients who underwent bariatric surgery had lower 5-year overall (24.9% vs. 37.1%; p<0.0001), liver-related (3.3% vs. 14%; p<0.0001), and non-liver-related mortality (22.3% vs. 26.9%; p=0.046). In multivariable analysis, bariatric surgery was associated with decreased overall mortality (adjusted hazard ratio [aHR]=0.63; p<0.0001), liver-related (aHR=0.24; p<0.0001), and non-liverrelated (aHR=0.81; p=0.0026) mortality. However, only laparoscopic surgeries were associated with lower overall mortality (aHR=0.39; p<0.0001) whereas open surgeries were associated with higher overall mortality (aHR=1.24; p=0.022).

CONCLUSION

Patients with MASLD and cirrhosis who underwent bariatric surgery, specifically laparoscopic approaches, had significantly lower mortality risk than non-surgical counterparts.

Resolution of Metabolic Dysfunction-associated Steatohepatitis With No Worsening of Fibrosis After Bariatric Surgery Improves 15-year Survival: A Prospective Cohort Study

BACKGROUND & AIMS

The aim of this study was to investigate the consequences of the histological progression of metabolic dysfunction-associated steatohepatitis (MASH) and fibrosis on long-term survival after bariatric surgery.

METHODS

From 1994 to 2021, 3028 patients at the University Hospital of Lille were prospectively included. Baseline liver biopsies were systematically performed with proposed follow-up biopsies 1 year after surgery, mainly in patients with MASH. We evaluated the association of the baseline and 1-year histologic progression of MASH and fibrosis status and long-term survival using Cox regression models.

RESULTS

At baseline, 2641 patients (89%) had a biopsy, including 232 with MASH (8.7%) and 266 (10.8%) with significant fibrosis (grade F2-F4). The median follow-up was 10.1 years. At 1 year, 594 patients had qualitative paired biopsies. Survival was shorter at the 15-year follow-up in patients with baseline MASH, than in those without (hazard ratio [HR], 2.21; 95% confidence interval [CI], 1.38-3.53) and in F2 to F4 than in F0 to F1 (HR, 3.38; 95% CI, 2.24-5.10). At the 1-year landmark analysis, compared with patients without baseline MASH, mortality increased in those with persistent MASH and/or if fibrosis worsened (adjusted HR, 2.54; 95% CI, 1.06-6.10), but not if MASH resolved without the worsening of fibrosis (adjusted HR, 0.73; 95% CI, 0.28-1.87). Similarly, compared with patients without significant fibrosis at baseline, patients with persistent significant fibrosis had increased mortality (adjusted HR, 4.03; 95% CI, 1.86-8.72) but not if fibrosis improved from F2 to F4 to F0 to F1 (adjusted HR; 1.49; 95% CI, 0.52-4.24).

CONCLUSION

Histologic remission of MASH or significant fibrosis improves survival after bariatric surgery.

Blood-based MASH diagnostic in candidates for bariatric surgery using mid-infrared spectroscopy: a European multicenter prospective study

Metabolic dysfunction-associated steatotic liver disease (MASLD) is common in individuals with obesity. Sexual dimorphism is present in MASLD. A noninvasive test to diagnose the severity of the disease, in particular the presence of Metabolic dysfunction-associated steatohepatitis (MASH), is lacking. This European multicenter prospective study uses a blood test based on mid-infrared (MIR) metabolic fingerprinting of individuals with severe or morbid obesity to diagnose MASH. Three hundred eighty-two individuals with severe or morbid obesity undergoing bariatric surgery were enrolled prospectively. Liver biopsies were obtained during surgery and assessed centrally. An algorithm was defined to calculate a score from the recorded MIR spectrum and to establish a diagnostic threshold to classify patients with MASH. Among the women (n = 217), MASH was diagnosed in 14.3% of cases. For women, the performance in terms of AUC were 0.83 and 0.82 in the calibration and validation groups, respectively. For a threshold of 0.1817, sensitivities were 86% and 70%, specificities were 81% and 75%, PPV were 43% and 32%, NPV were 97% and 94% and ACC were 82% and 74% for the calibration and validation groups, respectively. For men (n = 78; MASH: 33.3%), the performance of the spectral model was poor. The metabolic fingerprint obtained by MIR spectroscopy can rule out MASH in women with severe or morbid obesity. Its value in men needs new studies.Trial registration: ClinicalTrials.gov identifier: ClinicalTrials.gov identifier: NCT03978247 (04/06/2019).

Chronic treatment with glucagon-like peptide-1 and glucagon receptor co-agonist causes weight loss-independent improvements in hepatic steatosis in mice with diet-induced obesity

OBJECTIVES

Co-agonists at the glucagon-like peptide-1 and glucagon receptors (GLP1R/GCGR) show promise as treatments for metabolic dysfunction-associated steatotic liver disease (MASLD). Although most co-agonists to date have been heavily GLP1R-biased, glucagon directly acts on the liver to reduce fat content. The aims of this study were to investigate a GCGR-biased co-agonist as treatment for hepatic steatosis in mice.

METHODS

Mice with diet-induced obesity (DIO) were treated with Dicretin, a GLP1/GCGR co-agonist with high potency at the GCGR, Semaglutide (GLP1R monoagonist) or food restriction over 24 days, such that their weight loss was matched. Hepatic steatosis, glucose tolerance, hepatic transcriptomics, metabolomics and lipidomics at the end of the study were compared with Vehicle-treated mice.

RESULTS

Dicretin lead to superior reduction of hepatic lipid content when compared to Semaglutide or equivalent weight loss by calorie restriction. Markers of glucose tolerance and insulin resistance improved in all treatment groups. Hepatic transcriptomic and metabolomic profiling demonstrated many changes that were unique to Dicretin-treated mice. These include some known targets of glucagon signaling and others with as yet unclear physiological significance.

CONCLUSIONS

Our study supports the development of GCGR-biased GLP1/GCGR co-agonists for treatment of MASLD and related conditions.

The Relationship between Pathogenesis and Possible Treatments for the MASLD-Cirrhosis Spectrum

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a term that entails a broad spectrum of conditions that vary in severity. Its development is influenced by multiple factors such as environment, microbiome, comorbidities, and genetic factors. MASLD is closely related to metabolic syndrome as it is caused by an alteration in the metabolism of fatty acids due to the accumulation of lipids because of an imbalance between its absorption and elimination in the liver. Its progression to fibrosis is due to a constant flow of fatty acids through the mitochondria and the inability of the liver to slow down this metabolic load, which generates oxidative stress and lipid peroxidation, triggering cell death. The development and progression of MASLD are closely related to unhealthy lifestyle habits, and nutritional epigenetic and genetic mechanisms have also been implicated. Currently, lifestyle modification is the first-line treatment for MASLD and nonalcoholic steatohepatitis; weight loss of ≥10% produces resolution of steatohepatitis and fibrosis regression. In many patients, body weight reduction cannot be achieved; therefore, pharmacological treatment should be offered in particular populations.

Early prediction of the impact of public health policies on obesity and lifetime risk of type 2 diabetes: A modelling approach

OBJECTIVE

Help public health decision-making requires a better understanding of the dynamics of obesity and type 2 diabetes and an assessement of different strategies to decrease their burdens.

METHODS

Based on 97,848 individual data, collected in the French Health, Health Care and Insurance Survey over 1998-2014, a Markov model was developed to describe the progression of being overweight to obesity, and the onset of type 2 diabetes. This model traces and predicts 2022-2027 burdens of obesity and type 2 diabetes, and lifetime risk of diabetes, according to different scenarios aiming at minimum to stabilize obesity at 5 years.

RESULTS

Estimated risks of type 2 diabetes increase from 0.09% (normal weight) to 1.56% (obesity II-III). Compared to the before 1995 period, progression risks are estimated to have nearly doubled for obesity and tripled for type 2 diabetes. Consequently, over 2022-2027, the prevalence of obesity and type 2 diabetes will continue to increase from 17.3% to 18.2% and from 7.3% to 8.1%, respectively. Scenarios statibilizing obesity would require a 22%-decrease in the probability of move up (scenario 1) or a 33%-increase in the probability of move down (scenario 2) one BMI class. However, this stabilization will not affect the increase of diabetes prevalence whereas lifetime risk of diabetes would decrease (30.9% to 27.0%). Combining both scenarios would decrease obesity by 9.9%. Only the prevalence of obesity III shows early change able to predict the outcome of a strategy: for example, 6.7%-decrease at one year, 13.3%-decrease at two years with scenario 1 stabilizing obesity at 5 years.

CONCLUSIONS

Prevalences of obesity and type 2 diabetes will still increase over the next 5 years. Stabilizing obesity may decrease lifetime risks of type 2 diabetes without affecting its short-term prevalence. Our study highlights that, to early assess the effectiveness of their program, public health policy makers should rely on the change in prevalence of obesity III.

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.

Single-anastomosis duodeno-ileal bypass with sleeve gastrectomy improves lipid and glucose homeostasis in ob/ob mice

OBJECTIVE

The objective of this study was to compare the general and metabolic impact of single-anastomosis duodeno-ileal bypass with sleeve gastrectomy (SADI-S) with Roux-en-Y gastric bypass (RYGB) in an obese (ob/ob) mouse model.

METHODS

10-week-old male ob/ob mice underwent either SADI-S, RYGB, or laparotomy surgery (Sham group). General and metabolic parameters were assessed during a 5-week period thereafter.

RESULTS

SADI-S induced a deeper weight loss ([mean ± SEM] -41.2% ± 3.3%) than RYGB (-5.6% ± 3.5%, p < 0.001) compared with the Sham group (+6.3% ± 1.0%, p < 0.05). A significant food restriction was observed after SADI-S only (-31%, 117.4 ± 10.3 g vs. 170.2 ± 5.2 g of food at day 35 in Sham group mice, p < 0.001). Random-fed glycemia and glucose tolerance were more improved after SADI-S than RYGB. SADI-S decreased plasma cholesterol concentration by 60% (0.49 ± 0.04 g/L vs. 1.40 ± 0.10 g/L in the Sham group at day 35, p < 0.01), significantly more than RYGB (1.04 ± 0.14 g/L, p = 0.018). Plasma sitosterol/cholesterol and campesterol/cholesterol ratios were decreased after SADI-S, suggesting a reduced intestinal cholesterol absorption. SADI-S increased exogenous plasma cholesterol-D7 clearance and fecal elimination, also indicating an increased plasma cholesterol excretion. Studying a pair-fed group demonstrated that calorie restriction alone did not explain the beneficial impact of SADI-S.

CONCLUSIONS

SADI-S is associated with a greater improvement in lipid and glucose homeostasis than RYGB in ob/ob mice.

The role of bariatric surgery on beta-cell function and insulin resistance in patients with nonalcoholic fatty liver disease and steatohepatitis

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) and steatohepatitis (NASH) are strongly associated with obesity, metabolic syndrome, and insulin resistance (IR).

OBJECTIVE

The aim of this study was to investigate the effects of metabolic surgery on pancreatic beta cell function and IR in patients with obesity and NAFLD.

SETTING

University Hospital, Germany.

METHODS

Liver biopsies were taken intraoperatively from 112 patients undergoing sleeve gastrectomy (n = 68) or Roux-en-Y gastric bypass (n = 44) and analyzed histologically for the presence of simple steatosis (NAFL) or NASH. Clinical and biochemical parameters were collected over up to 2 years. Beta cell function and IR were assessed using the homeostasis model assessment of beta-cell function (HOMA2-%B) and insulin resistance (HOMA2-IR) index.

RESULTS

NASH was present in 53.6% (n = 60) of the patients and NAFL in 25.9% (n = 29). Liver enzymes, adiponectin/leptin ratio, triglycerides, and HbA1C were improved at 6 months, 1, and 2 years after surgery. HOMA2-IR was significantly lower in patients without NAFLD while HOMA2-IR did not differ between patients with NAFL and/or NASH. HOMA2-%B was highest in the NAFLD group and lowest in patients with NASH. While there was no change in HOMA2-%B and HOMA2-IR in the No-NAFLD group, HOMA2-%B decreased and IR improved in the NAFL and NASH groups.

CONCLUSION

Insufficient compensatory beta-cell function may contribute to the progression from NAFL alongside with IR to NASH. Our findings suggest that bariatric surgery decreases IR while at the same time reducing compensatory insulin oversecretion. These results are associated with beneficial changes in adipose tissue function after bariatric surgery.

Gut Microbiota and Plasma Bile Acids Associated with Non-Alcoholic Fatty Liver Disease Resolution in Bariatric Surgery Patients

Bariatric surgery (BS) has several benefits, including resolution of non-alcoholic fatty liver disease (NAFLD) in many patients. However, a significant percentage of patients do not experience improvement in fatty liver after BS, and more than 10% develop new or worsening NAFLD features. Therefore, a question that remains unanswered is why some patients experience resolved NAFLD after BS and others do not. In this study, we investigated the fecal microbiota and plasma bile acids associated with NAFLD resolution in twelve morbidly obese patients undergoing BS, of whom six resolved their steatosis one year after surgery and another six did not. Results indicate that the hallmark of the gut microbiota in responder patients is a greater abundance of Bacteroides, Akkermansia, and several species of the Clostridia class (genera: Blautia, Faecalibacterium, Roseburia, Butyricicoccusa, and Clostridium), along with a decreased abundance of Actinomycetes/Bifidobacterium and Faecalicatena. NAFLD resolution was also associated with a sustained increase in primary bile acids (particularly non-conjugated), which likely results from a reduction in bacterial gut species capable of generating secondary bile acids. We conclude that there are specific changes in gut microbiota and plasma bile acids that could contribute to resolving NAFLD in BS patients. The knowledge acquired can help to design interventions with prebiotics and/or probiotics to promote a gut microbiome that favors NAFLD resolution.

Temporal Relationship Between Insulin Resistance and Lipid Accumulation After Bariatric Surgery: a Multicenter Cohort Study

PURPOSE

Insulin resistance (IR) is closely associated with lipid accumulation. Here, we investigated the temporal relationship between the two conditions after bariatric surgery.

MATERIALS AND METHODS

In total, 409 participants were enrolled from three bariatric centers in China from 2009 to 2018. We evaluated whether baseline IR (proxied by homeostasis model assessment of insulin resistance (HOMA-IR)) and lipid accumulation (proxied by visceral adiposity index (VAI) and lipid accumulation product (LAP)) were associated with follow-up IR and lipid accumulation (3 months postoperatively) using linear regression models. We then conducted a cross-lagged panel analysis model to simultaneously examine the bidirectional relationship between IR and lipid accumulation.

RESULTS

Multivariable linear regression analyses showed that baseline HOMA-IR was associated with follow-up VAI (β = 0.430, 95% CI: 0.082-0.778, p = 0.016) and LAP (β = 0.070, 95% CI: 0.010-0.130, p = 0.022). There was no relationship between baseline lipid accumulation and follow-up IR. Further cross-lagged panel analyses indicated that the path coefficient from baseline HOMA-IR to follow-up VAI (β₂ = 0.145, p = 0.003) was significantly greater than the coefficient from baseline VAI to follow-up HOMA-IR (β₁ =  - 0.013, p = 0.777). Similarly, the path coefficient from baseline HOMA-IR to follow-up LAP (β₂ = 0.141, p = 0.003) was significantly greater than the coefficient from baseline LAP to follow-up HOMA-IR (β₁ = 0.041, p = 0.391).

CONCLUSION

Our study demonstrated a unidirectional relationship from HOMA-IR to VAI and LAP, suggesting that the change in IR may precede lipid accumulation after surgery.

A Review of Defatting Strategies for Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease is a huge cause of chronic liver failure around the world. This condition has become more prevalent as rates of metabolic syndrome, type 2 diabetes, and obesity have also escalated. The unfortunate outcome for many people is liver cirrhosis that warrants transplantation or being unable to receive a transplant since many livers are discarded due to high levels of steatosis. Over the past several years, however, a great deal of work has gone into understanding the pathophysiology of this disease as well as possible treatment options. This review summarizes various defatting strategies including in vitro use of pharmacologic agents, machine perfusion of extracted livers, and genomic approaches targeting specific proteins. The goal of the field is to reduce the number of necessary transplants and expand the pool of organs available for use.

Nonalcoholic Fatty Liver Disease and Its Complex Relation with Type 2 Diabetes Mellitus—From Prevalence to Diagnostic Approach and Treatment Strategies

Prevalence of Nonalcoholic Fatty Liver Disease (NAFLD) and Type 2 Diabetes Mellitus (T2DM) are increasing rapidly worldwide, reaching epidemic proportions. Their association, based on common metabolic risk factors (obesity, insulin resistance (IR), unhealthy lifestyle), brings an additional risk of both hepatic and cardiovascular (CV) adverse clinical outcomes. The terminology of “NAFLD” is stigmatizing to some but not all patients, and a more practical one should be announced soon. Medical strategies can address both diseases simultaneously, as they have crossing pathophysiological mechanisms, mainly IR. Strategies vary from lifestyle intervention and pharmacological options, as more molecules designated for T2DM treatment may be helpful in NAFLD, to surgical procedures. This review focuses on the coexistence of NAFLD and T2DM, pointing out the utility of the appropriate terminology, its prevalence, and mortality rates among the diabetic population. Briefly, we have discussed the main pathophysiological mechanisms and the risk stratification algorithm for the development of NAFLD and nonalcoholic steatohepatitis (NASH) as well as the tools for evaluation of fibrosis. Finally, we have focused on the current therapeutic options for the treatment of NAFLD associated with T2DM.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Prevalence and predictors of non-alcoholic steatohepatitis in patients with morbid obesity

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is highly prevalent in morbid obesity (MO). A considerable proportion of patients with MO have non-alcoholic steatohepatitis (NASH). Liver biopsy (LB) is the only procedure that reliably differentiates NASH from other stages of NAFLD, but its invasive nature prevents it from being generalisable. Hence, non-invasive assessment is critical in this group of patients.

OBJECTIVES

To report NAFLD/NASH prevalence in a cohort of patients with MO and to identify predictors of NASH.

METHODS

Fifty-two consecutive patients subjected to bariatric surgery in a University hospital in Spain underwent LB. Anthropometric, clinical and biochemical variables were registered. According of the results of the LB, individuals were classified by whether they had NASH or not. Multiple logistic regression analysis was performed to identify independent factors associated with NASH.

RESULTS

NAFLD was reported in 94.2% of the patients, simple steatosis was present in 51.92% and NASH in 42.31%. Meanwhile, 17.3% of patients exhibited significant fibrosis (≥F2). HIGHT score for NASH risk was established using five independent predictors: systemic Hypertension, Insulin resistance, Gamma-glutamyl transferase, High density lipoprotein cholesterol and alanine Transaminase. This score ranges from 0 to 7 and was used to predict NASH in our cohort (area under the receiver operator characteristic curve 0.846). A score of 4 or greater implied high risk (sensitivity 77.3%, specificity 73.3%, positive predictive value 68%, negative predictive value 81.5%, accuracy 75%).

CONCLUSIONS

NAFLD is practically a constant in MO with a considerable proportion of patients presenting NASH. The combination of five independent predictors in a scoring system may help the clinician optimise the selection of patients with MO for LB.

Bariatric Surgery in NAFLD

Currently, there are no approved medications to treat patients with nonalcoholic steatohepatitis (NASH) with fibrosis or cirrhosis. Although the management goal in these patients is weight reduction by 7-10% with lifestyle modifications, only less than 10% of patients achieve this target at 1-year, and fewer maintain the weight loss at 5 years. Bariatric surgery is an option that may be considered in those who fail to lose weight by lifestyle changes. Bariatric surgery has been shown to improve liver histology including fibrosis secondary to NASH, in addition to other benefits including an improvement or resolution of type 2 diabetes mellitus, dyslipidemia, and hypertension, and a reduction of cardiovascular morbidity or mortality. There are no guidelines of bariatric surgery indications for the management of NASH. The purpose of this review is to critically appraise the current knowledge of the role of bariatric surgery and the potential mechanisms for its perceived benefits in the management of patients with NASH-related liver disease.

Preoperative circulating peroxiredoxin 1 levels as a predictor of non-alcoholic fatty liver disease remission after laparoscopic bariatric surgery

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is associated with obesity and insulin resistance and can be improved after bariatric surgery. Circulating Peroxiredoxin 1 (Prdx1) protein was reported to regulate energy metabolism and inflammation. This study aimed to investigate the roles of serum prdx1 in NAFLD patients with obesity undergoing LSG and to develop a prognostic model to predict the remission of severe NAFLD.

METHODS

The data of 93 participants from a tertiary hospital were assessed. Before laparoscopic sleeve gastrectomy (LSG) and three months after LSG, anthropometric parameters, laboratory biochemical data, and abdominal B-ultrasound results were collected, and their hepatic steatosis index (HSI) and triglyceride-glucose index (TyG) were calculated. A NAFLD improvement (NAFLD-I) nomogram prediction model was constructed using the least absolute shrinkage and selection operator (LASSO) regression and multiple regression, and its predictive ability was verified in a validation cohort.

RESULTS

The baseline Prdx1 (OR: 0.887, 95% CI: 0.816-0.963, p=0.004), preoperative TyG (OR: 8.207, 95% CI: 1.903-35.394, p=0.005) and HSI (OR: 0.861, 95% CI: 0.765-0.969, p=0.013) levels were independently associated with NAFLD-I at three months after LSG in NAFLD patients with obesity. In the primary and validation cohorts, the area under the receiver operating characteristic (AUC) of the developed nomogram model was 0.891 and 0.878, respectively. The preoperative circulating Prdx1 levels of NAFLD patients with obesity were significantly reduced after LSG (25.32 [18.99-30.88] vs. 23.34 [15.86-26.42], p=0.001). Prdx1 was related to obesity and hepatic steatosis based on correlation analysis.

CONCLUSION

The nomogram based on preoperative serum prdx1, HSI and TyG could be an effective tool for predicting remission of severe NAFLD after LSG.

Efficacy and safety of endoscopic sleeve gastroplasty versus laparoscopic sleeve gastrectomy in obese subjects with Non-Alcoholic SteatoHepatitis (NASH): study protocol for a randomized controlled trial (TESLA-NASH study)

BACKGROUND

Non-alcoholic steatohepatitis (NASH) is frequently associated with obesity, and its standard treatment is weight loss with diet and exercise; a dy% weight reduction has been associated with improvement in liver histological and analytical abnormalities. However, less than 25% of subjects achieve this goal. Laparoscopic sleeve gastrectomy (LSG) represents the most common procedure of bariatric surgery, providing effective weight loss and improvement in comorbidities such as NASH, but it is associated with several postoperative complications. Endoscopic bariatric techniques are currently on the rise as a new tool in the fight against obesity, offering patients an alternative to more invasive surgery. However, their efficacy and safety compared with LSG is unclear.

METHODS

The TESLA-NASH study is a randomized, controlled, open-label, unicentric clinical trial with a medical device. The aim of this study is to evaluate and compare the efficacy and safety of endoscopic sleeve gastroplasty (ESG) versus laparoscopic sleeve gastrectomy (LSG) in liver histology improvement of patients with obesity +/- metabolic syndrome and NASH. A total of 30 patients will be randomized 1:1 to the experimental or control group.

DISCUSSION

LSG is an effective treatment for weight reduction and for the remission of hepatic alterations. However, LSG is associated with acute and chronic postoperative complications. Bariatric endoscopic techniques promise less invasive and more cost-effective approaches to the treatment of obesity and metabolic comorbidities. ESG represents one of the most promising novel endoscopic interventions and it is mainly proposed for patients with mild-to-moderate obesity, but there are still no guidelines that specify its applicability criteria. This clinical trial will help us apply different tactics to the treatment of obesity and NASH.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04060368. Registered on Nov 15, 2019.

Prevalence and predictors of non-alcoholic steatohepatitis in patients with morbid obesity

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is highly prevalent in morbid obesity (MO). A considerable proportion of patients with MO have non-alcoholic steatohepatitis (NASH). Liver biopsy (LB) is the only procedure that reliably differentiates NASH from other stages of NAFLD, but its invasive nature prevents it from being generalisable. Hence, non-invasive assessment is critical in this group of patients.

OBJECTIVES

To report NAFLD/NASH prevalence in a cohort of patients with MO and to identify predictors of NASH.

METHODS

Fifty-two consecutive patients subjected to bariatric surgery in a University hospital in Spain underwent LB. Anthropometric, clinical and biochemical variables were registered. According of the results of the LB, individuals were classified by whether they had NASH or not. Multiple logistic regression analysis was performed to identify independent factors associated with NASH.

RESULTS

NAFLD was reported in 94.2% of the patients, simple steatosis was present in 51.92% and NASH in 42.31%. Meanwhile, 17.3% of patients exhibited significant fibrosis (≥F2). HIGHT score for NASH risk was established using five independent predictors: systemic Hypertension, Insulin resistance, Gamma-glutamyl transferase, High density lipoprotein cholesterol and alanine Transaminase. This score ranges from 0 to 7 and was used to predict NASH in our cohort (area under the receiver operator characteristic curve 0.846). A score of 4 or greater implied high risk (sensitivity 77.3%, specificity 73.3%, positive predictive value 68%, negative predictive value 81.5%, accuracy 75%).

CONCLUSIONS

NAFLD is practically a constant in MO with a considerable proportion of patients presenting NASH. The combination of five independent predictors in a scoring system may help the clinician optimise the selection of patients with MO for LB.

Liver Transplantation After Bariatric Surgery: a Clinical Cohort Study

PURPOSE

Individuals that undergo bariatric surgery are at higher risk for problematic alcohol use via pharmacokinetic changes in alcohol metabolism and cross addictions. Little data exists regarding post-bariatric surgery patients with alcohol-related liver disease (ALD) who ultimately require liver transplantation. The aim of this project was to better understand demographic, medical, and psychological characteristics of post-bariatric surgery patients who undergo liver transplantation due to ALD.

METHODS

This retrospective clinical cohort identified 1416 patients who underwent ALD liver transplantation over a 10-year timespan at three academic medical centers. Electronic medical records were reviewed for patient characteristics, including sex, age, body mass index, surgery dates, Model for End Stage Liver Disease (MELD) scores, medical history, psychiatric history, and mortality rates.

RESULTS

Within the sample of liver transplantation patients, 1.3% had undergone bariatric surgery prior to transplantation. Fifty percent of the post-bariatric surgery sample was female. The MELD score was higher and the median age at transplantation was younger in the post-bariatric surgery subgroup in comparison to that in the non-bariatric surgery patients. Mood and anxiety disorders were more common among those with a history of having bariatric surgery, with major depressive disorder having the largest difference between subgroups.

CONCLUSIONS

Among patients who require a liver transplantation due to ALD, those with a history of bariatric surgery are more likely to be female, younger, and diagnosed with mood disorders. Further studies with larger and more diverse samples are necessary to better understand how to prevent development of alcohol use disorder in the bariatric surgery population.

Caspase-Cleaved Keratin 18 Measurements Identified Ongoing Liver Injury after Bariatric Surgery

Bariatric surgery has emerged as an effective treatment option in morbidly obese patients with non-alcoholic fatty liver disease (NAFLD). However, worsening or new onset of non-alcoholic steatohepatitis (NASH) and fibrosis have been observed. Caspase-cleaved keratin 18 (ccK18) has been established as a marker of hepatocyte apoptosis, a key event in NASH development. Thus, ccK18 measurements might be feasible to monitor bariatric surgery patients. Clinical data and laboratory parameters were collected from 39 patients undergoing laparoscopic Roux-en-Y gastric bypass at six timepoints, prior to surgery until one year after the procedure. ccK18 levels were measured and a high-throughput analysis of serum adipokines and cytokines was carried out. Half of the cohort’s patients (20/39) presented with ccK18 levels indicative of progressed liver disease. 21% had a NAFLD-fibrosis score greater than 0.676, suggesting significant fibrosis. One year after surgery, a mean weight loss of 36.87% was achieved. Six and twelve months after surgery, ccK18 fragments were significantly reduced compared to preoperative levels (p < 0.001). Yet nine patients did not show a decline in ccK18 levels ≥ 10% within one year postoperatively, which was considered a response to treatment. While no significant differences in laboratory parameters or ccK18 could be observed, they presented with a greater expression of leptin and fibrinogen before surgery. Consecutive ccK18 measurements monitored the resolution of NAFLD and identified non-responders to bariatric surgery with ongoing liver injury. Further studies are needed to elicit the pathological mechanisms in non-responders and study the potential of adipokines as prognostic markers.

Insulin Resistance Is Central to Long-Term Reversal of Histologic Nonalcoholic Steatohepatitis After Metabolic Surgery

CONTEXT

Nonalcoholic steatohepatitis (NASH) is considered the hepatic counterpart of metabolic syndrome.

OBJECTIVE

This work aimed to investigate the determinants of NASH reversal in patients undergoing biliopancreatic diversion (BPD) in a 5-year follow-up study.

METHODS

This prospective study was conducted at Policlinico Universitario Agostino Gemelli. A total of 37 patients underwent fine-needle liver biopsy during BPD. Ultrasonography-guided percutaneous liver biopsy was obtained 5 years after the operation. The primary outcome of our study was histologic NASH reversal at 5-year follow-up. To better characterize the clinical variables involved in the resolution of NASH, we also compared patients without histologic NASH resolution at 5 years with those in whom NASH had disappeared.

RESULTS

At follow-up, NASH had reversed in 56.5% of the patients. The NAFLD activity score (NAS) improved from 3.7 ± 0.93 to 2 ± 1.11 (P < .001). Fibrosis reversed in 16% patients (P = .022), and 32% improved (95% CI, 0.05-0.54). No significant differences in body mass index or clinical parameters changes explained the effect of surgery on NASH, apart from the measure of insulin sensitivity post surgery. The Homeostasis Model Assessment of Insulin Resistance decreased from 3.31 ± 1.72 at baseline to 1.73 ± 1.08 (P < .001) after BPD, and the Matsuda index improved from 2.66 ± 1.79 to 4.73 ± 3.05 (P < .001). The lipid profile normalized (total cholesterol from 4.75 ± 1.18 to 3.32 ± 0.77 mmol/L, P < .001; low-density lipoprotein cholesterol from 2.92 ± 0.91 to 1.60 ± 0.51 mmol/L, P = .0001; high-density lipoprotein cholesterol from 0.97 ± 0.33 to 1.10 ± 0.35 mmol/L, P = .023; triglycerides from 2.52 ± 1.6 to 1.47 ± 0.67 mmol/L, P = .003). Neural network analysis showed that the end-study Matsuda index discriminated between responders and nonresponders with high accuracy (receiver operating characteristic area under the curve = 0.98%).

CONCLUSION

Remission of NASH is driven by reversal of whole-body insulin resistance post intervention.

Established and emerging factors affecting the progression of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) has become the most common chronic liver disease affecting approximately 25% of the global population. Although a majority of NAFLD patients will never experience liver-related symptoms it is estimated that 5-10% will develop cirrhosis-related complications with risk of death or need for liver transplantation. NAFLD is closely associated with cardiovascular disease and components of the metabolic syndrome. However, NAFLD is not uncommon in lean individuals and may in these subjects represent a different entity with separate pathophysiological mechanisms involved implying a higher risk for development of end-stage liver disease. There is considerable fluctuation in the histopathological course of NAFLD that may partly be attributed to lifestyle factors and dietary composition. Nutrients such as fructose, monounsaturated fatty acids, and trans-fatty acids may aggravate NAFLD. Presence of type 2 diabetes mellitus seems to be the most important clinical predictor of liver-related morbidity and mortality in NAFLD. Apart from severity of the metabolic syndrome, genetic polymorphisms and environmental factors, such as moderate alcohol consumption, may explain the variation in histopathological and clinical outcome among NAFLD patients.

Bariatric Surgery Provides Long-term Resolution of Nonalcoholic Steatohepatitis and Regression of Fibrosis

BACKGROUND AND AIMS

Studies are needed to determine the long-term effects of bariatric surgery for patients with nonalcoholic steatohepatitis (NASH). We evaluated sequential liver samples, collected the time of bariatric surgery and 1 and 5 years later, to assess the long-term effects of bariatric surgery in patients with NASH.

METHODS

We performed a prospective study of 180 severely obese patients with biopsy-proven NASH, defined by the NASH clinical research network histologic scores. The patients underwent bariatric surgery at a single center in France and were followed for 5 years. We obtained liver samples from 125 of 169 patients (76%) having reached 1 year and 64 of 94 patients (68%) having reached 5 years after surgery. The primary endpoint was the resolution of NASH without worsening of fibrosis at 5 years. Secondary end points were improvement in fibrosis (reduction of ≥1 stage) at 5 years and regression of fibrosis and NASH at 1 and 5 years.

RESULTS

At 5 years after bariatric surgery, NASH was resolved, without worsening fibrosis, in samples from 84% of patients (n = 64; 95% confidence interval, 73.1%-92.2%). Fibrosis decreased, compared with baseline, in samples from 70.2% of patients (95% CI, 56.6%-81.6%). Fibrosis disappeared from samples from 56% of all patients (95% CI, 42.4%-69.3%) and from samples from 45.5% of patients with baseline bridging fibrosis. Persistence of NASH was associated with no decrease in fibrosis and less weight loss (reduction in body mass index of 6.3 ± 4.1 kg/m² in patients with persistent NASH vs reduction of 13.4 ± 7.4 kg/m²; P = .017 with resolution of NASH). Resolution of NASH was observed at 1 year after bariatric surgery in biopsies from 84% of patients, with no significant recurrence between 1 and 5 years (P = .17). Fibrosis began to decrease by 1 year after surgery and continued to decrease until 5 years (P < .001).

CONCLUSIONS

In a long-term follow-up of patients with NASH who underwent bariatric surgery, we observed resolution of NASH in liver samples from 84% of patients 5 years later. The reduction of fibrosis is progressive, beginning during the first year and continuing through 5 years.

Roux-en-Y Gastric Bypass in Obese Diabetic Rats Promotes Autophagy to Improve Lipid Metabolism through mTOR/p70S6K Signaling Pathway

PURPOSE

To investigate the effects of Roux-en-Y gastric bypass (RYGB) surgery on markers of liver mitochondrial dynamics and find new therapeutic basis on obese type 2 diabetes mellitus (T2DM) patients. Materials and Methods. Thirty-two rats were divided into nondiabetic group, diabetic group, sham group, and RYGB group. The Dual-energy X-ray absorptiometry (DEXA) was used to detect short-term curriculum vitae for rat body component and fat and lean mass. Hepatic lipid content and triglyceride levels were detected by Oil Red O staining. Western blotting was used to examine autophagy and mammalian target of rapamycin/P70S6 kinase (mTOR/p70S6K) pathway-related proteins. The carbon dioxide production from the oxidation of [¹⁴C] oleate was measured. Plasma glucose was measured by glucose oxidase assay. The insulin and C-peptide were detected. Triacylglyceride (TG) and free fat acid (FFA) in plasma were determined by enzymatic colorimetric assays.

RESULTS

RYGB improved metabolic parameters and enhanced plasma GLP-1 level, ameliorated the lipopexia, and increased insulin sensitivity in the liver; RYGB promoted the hepatic autophagy and inhibited the mTOR/p70S6K signaling pathway. GLP-1 reduced fat load and increased fatty acid β-oxidation by activated autophagy to regulate the hepatic lipid pathway through mTOR/p70S6K signaling pathway.

CONCLUSIONS

RYGB may reduce liver lipid toxicity and improve insulin sensitivity through activating the hepatic fat hydrolysis pathway and inhibiting the liver fat synthesis pathway. However, the transport pathway of liver fat does not play a key role.

Multiparametric Magnetic Resonance Elastography Improves the Detection of NASH Regression Following Bariatric Surgery

Disease monitoring in nonalcoholic steatohepatitis (NASH) is limited by absence of noninvasive biomarkers of disease regression or progression. We aimed to examine the role of multiparametric three-dimensional magnetic resonance elastography (3D-MRE) and magnetic resonance imaging proton density fat fraction (MRI-PDFF) in the detection of NASH regression after interventions. This is a single-center prospective clinical trial of 40 patients who underwent bariatric surgery. Imaging and liver biopsies were obtained at baseline and 1 year after surgery. The imaging protocol consisted of multifrequency 3D-MRE to determine the shear stiffness at 60 Hz and damping ratio at 40 Hz, and MRI-PDFF to measure the fat fraction. A logistic regression model including these three parameters was previously found to correlate with NASH. We assessed the model performance in the detection of NASH resolution after surgery by comparing the image-predicted change in NAFLD activity score (delta NAS) to the histologic changes. A total of 38 patients (median age 43, 87% female, 30 of 38 with NAS ≥ 1, and 13 of 38 with NASH) had complete data at 1 year. The NAS decreased in all subjects with NAS ≥ 1 at index biopsy, and NASH resolved in all 13. There was a strong correlation between the predicted delta NAS by imaging and the delta NAS by histology (r = 0.73, P < 0.001). The strength of correlation between histology and the predicted delta NAS using single conventional parameters, such as the fat fraction by MRI-PDFF or shear stiffness at 60 Hz by MRE, was r = 0.69 (P < 0.001) and r = 0.43 (P = 0.009), respectively. Conclusion: Multiparametric 3D-MRE and MRI-PDFF can detect histologic changes of NASH resolution after bariatric surgery. Studies in a nonbariatric setting are needed to confirm the performance as a composite noninvasive biomarker for longitudinal NASH monitoring.

The mid-infrared spectroscopy: A novel non-invasive diagnostic tool for NASH diagnosis in severe obesity

There is an urgent medical need to develop non-invasive tests for non-alcoholic steatohepatitis (NASH). This study evaluates the diagnostic performance of an innovative model based on mid-infrared (MIR) spectroscopy for the diagnosis of NASH.

Methods

Severely obese patients who underwent a bariatric procedure at the University Hospital of Nice, France (n = 395) were prospectively recruited. The clinico-biological characteristics were measured prior to surgery. Liver biopsies were collected during the surgical procedure and assessed by a pathologist. A training group (316 patients, NASH: 16.8%) and a validation group (79 patients, NASH: 16.5%) were randomly defined. MIR spectra were acquired by fiber evanescent wave spectroscopy, using chalcogenide glass fiber optic sensors and a spectrometer. This absorption spectroscopic technique delivers a spectrum that identifies the molecular composition of a sample, defining a patient's metabolic fingerprint.

Results

The areas under the receiver operating curve (AUROC) for the diagnosis of NASH were 0.82 and 0.77 in the training and validation groups, respectively. The best threshold was 0.15, which was associated with a sensitivity of 0.75 and 0.69, and a specificity of 0.72 and 0.76. Negative predictive values of 0.94 and 0.93 and positive predictive values of 0.35 and 0.36, as well as correctly classified patient rates of 72% and 75% were obtained in the training and validation groups, respectively. A composite model using aspartate aminotransferase level, triglyceride level and waist circumference alongside the MIR spectra led to an increase in AUROC (0.88 and 0.84 for the training and validations groups, respectively).

Conclusions

MIR spectroscopy provides good sensitivity and negative predictive values for NASH screening in patients with severe obesity.

Lay summary

There is an urgent need for tools to non-invasively diagnose and monitor non-alcoholic steatohepatitis (NASH). This study evaluates the performance of a new tool for fast NASH diagnosis based on mid-infrared (MIR) spectroscopy. Using serum samples from severely obese patients who underwent a bariatric procedure, which enabled a concomitant liver biopsy to be performed, the MIR spectroscopy model performed well in screening patients for NASH compared to a traditional, histological diagnosis.

•

There is no validated non-invasive diagnostic tool for NASH in routine care.

•

NASH follow-up requires a non-invasive diagnostic method.

•

Using a simple drop of serum, the mid-infrared spectrum captures a patient’s metabolic fingerprint.

•

A model based on mid-infrared spectroscopy provides efficient NASH screening for patients with severe obesity.

Complete Resolution of Nonalcoholic Fatty Liver Disease After Bariatric Surgery: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

Bariatric surgery has been reported to lead to complete resolution of nonalcoholic fatty liver disease (NAFLD) following the sustained weight loss induced in obese patients. We performed a systematic review and meta-analysis to evaluate the effects of bariatric surgery on NAFLD in obese patients.

METHODS

We searched MEDLINE, EMBASE, CENTRAL, and Web of Science databases through May 2018 for studies that compared liver biopsy results before and after bariatric surgery in obese patients. Primary outcomes were biopsy-confirmed resolution of NAFLD and NAFLD activity score. Secondary outcomes were worsening of NAFLD after surgery and liver volume. The Grading of Recommendations, Assessment, Development, and Evidence approach was conducted to assess overall quality of evidence.

RESULTS

We analyzed data from 32 cohort studies comprising 3093 biopsy specimens. Bariatric surgery resulted in a biopsy-confirmed resolution of steatosis in 66% of patients (95% CI, 56%-75%), inflammation in 50% (95% CI, 35%-64%), ballooning degeneration in 76% (95% CI, 64%-86%), and fibrosis in 40% (95% CI, 29%-51%). Patients' mean NAFLD activity score was reduced significantly after bariatric surgery (mean difference, 2.39; 95% CI, 1.58-3.20; P < .001). However, bariatric surgery resulted in new or worsening features of NAFLD, such as fibrosis, in 12% of patients (95% CI, 5%-20%). The overall Grading of Recommendations, Assessment, Development, and Evidence quality of evidence was very low.

CONCLUSIONS

Through this systematic review and meta-analysis, we found that bariatric surgery leads to complete resolution of NAFLD in obese patients. However, some patients develop new or worsened features of NAFLD. Randomized controlled trials are needed to further examine the therapeutic benefits of bariatric surgery for patients with NAFLD.

Bariatric surgery in patients with non-alcoholic fatty liver disease - from pathophysiology to clinical effects

Non-alcoholic fatty liver disease (NAFLD) is increasingly recognized as a significant liver disease, and it covers the disease spectrum from simple steatosis with a risk of development of non-alcoholic steatohepatitis (NASH) to fibrosis, subsequent cirrhosis, end-stage liver failure, and liver cancer with a potential need for liver transplantation. NAFLD and NASH are closely related to obesity, metabolic syndrome, and type 2 diabetes (T2D). The role of gut hormones, especially glucagon-like peptide 1 (GLP-1), is important in NAFLD. Bariatric surgery has the potential for inducing great weight loss and may improve the symptoms of metabolic syndrome and T2D. Recent data demonstrated significant effects of bariatric surgery on GLP-1 and other gut hormones and important lipid metabolic and inflammatory abnormalities in the pathophysiology of NAFLD. Therefore, bariatric surgery may reverse the pathological liver changes in NAFLD and NASH patients. In the present review, we describe NAFLD and NASH pathophysiology and the primary effects of bariatric surgery on metabolic pathways. We performed a systematic review of the beneficial and harmful effects and focused on changes in liver disease severity in NAFLD and NASH patients. The specific focus was liver histopathology as assessed by the invasive liver biopsy. Additionally, we reviewed several non-invasive methods used for the assessment of liver disease severity following bariatric surgery.

ESPEN guideline on clinical nutrition in liver disease

This update of evidence-based guidelines (GL) aims to translate current evidence and expert opinion into recommendations for multidisciplinary teams responsible for the optimal nutritional and metabolic management of adult patients with liver disease. The GL was commissioned and financially supported by ESPEN. Members of the guideline group were selected by ESPEN. We searched for meta-analyses, systematic reviews and single clinical trials based on clinical questions according to the PICO format. The evidence was evaluated and used to develop clinical recommendations implementing the SIGN method. A total of 85 recommendations were made for the nutritional and metabolic management of patients with acute liver failure, severe alcoholic steatohepatitis, non-alcoholic fatty liver disease, liver cirrhosis, liver surgery and transplantation as well as nutrition associated liver injury distinct from fatty liver disease. The recommendations are preceded by statements covering current knowledge of the underlying pathophysiology and pathobiochemistry as well as pertinent methods for the assessment of nutritional status and body composition.

Recommendations for Management and Treatment of Nonalcoholic Steatohepatitis

The prevalence of nonalcoholic liver disease (NAFLD) is increasing worldwide in conjunction with the epidemic increase in obesity and metabolic risk factors. Consequently, NAFLD has become a leading indication for liver transplantation. Although genetic factors play an important role in the pathogenesis of NAFLD, detrimental lifestyle trends favoring a calorically unrestricted diet rich in carbohydrates and unsaturated fat, prolonged sedentary periods or limited physical activity have major metabolic implications. In aggregate these physiological dysregulations constitute the main risk factors for the metabolic syndrome and NAFLD. The cornerstone of the treatment of NAFLD, is lifestyle changes, including modifications to diet and physical activity, to reduce body weight and liver fat, however adherence is notoriously poor and the epidemic of NAFLD continues to grow unimpeded. In the face of this unmet clinical need, the pharmacologic therapy of NAFLD has been expanding as the varied mechanistic pathways of NAFLD are elucidated. Beyond these approaches to treating NAFLD, the prevention of other liver diseases is additionally important. Chief among these is alcoholic liver disease, and heavy use is detrimental irrespective of underlying NAFLD. However, the impact of mild to moderate alcohol use in patients with mild or nonadvanced forms NAFLD is undefined. This article summarizes the results of the International Liver Transplantation Society consensus meeting on NAFLD in liver transplantation. It describes the available evidence and provides consensus guidance on the lifestyle and pharmacologic therapies of NAFLD, and the consensus position on alcohol use in patients with NAFLD.

Current and future therapeutic regimens for nonalcoholic fatty liver disease and nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) and its progressive form non-alcoholic steatohepatitis (NASH), are rapidly becoming among the top causes of cirrhosis, hepatocellular carcinoma, and indications for liver transplantation. Other than lifestyle modification through diet and exercise, there are currently no other approved treatments for NASH/NAFLD. Although weight loss can be effective, it is difficult to achieve and sustain. In contrast, bariatric surgery can improve metabolic conditions associated with NAFLD, and has been shown to improve liver histology. To have approved regimens for the treatment of NASH/NAFLD, several issues must be addressed. First, all stakeholders must agree on the most appropriate clinical trial endpoints for NASH. Currently, resolution of NASH (without worsening fibrosis) or reduction of fibrosis stage (without worsening NASH) are the accepted endpoints by the regulatory authorities. It is important to recognize the prognostic implication of histologic features of NASH. In this context, although histologic NASH has been associated with advanced fibrosis, it is not an independent predictor of long-term mortality. In contrast, there are significant data to suggest that fibrosis stage is the only robust and independent predictor of liver-related mortality. In addition to the primary endpoints, several important secondary endpoints, including noninvasive biomarkers, long-term outcomes, and patient-reported outcomes must be considered. In 2018, a few phase 3 clinical trials for the treatment of NASH have been initiated. Additionally, a number of phase 2a and 2b clinical trials targeting different pathogenic pathways in NASH are in the pipeline of emerging therapies.

CONCLUSION

Over the next 5 years, some of these regimens are expected to provide potential new treatment options for patients with NASH/NAFLD. (Hepatology 2018;68:361-371).

Renal Function and Remission of Hypertension After Bariatric Surgery: a 5-Year Prospective Cohort Study

PURPOSE

This study examines the effect of Roux-en-Y gastric bypass (RYGB) and laparoscopic adjustable gastric banding (LAGB) on renal function for at least 5 years post-operatively in a tertiary referral center for bariatric surgery.

MATERIALS AND METHODS

This prospective cohort study of patients undergoing RYGB and LAGB measured renal function, blood pressure, and diabetes status pre-operatively and then 1 and 5 years post-operatively. Renal function was assessed using the Modification of Diet in Renal Disease (MDRD), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), and Cockcroft-Gault formulae. Hypertension and diabetes were defined by the European Society of Hypertension and European Society of Cardiology joint guidelines and American Diabetes Association guidelines, respectively. A sub-group who had completed 10 years post-operative follow-up was also included.

RESULTS

Estimated glomerular filtration rate (eGFR) increased over 5 years after RYGB (N = 190; 94 ± 2 mL/min/1.73 m² to 102 ± 22 mL/min/1.73 m², p = 0.01) and LAGB (N = 271; 88 ± 1 to 93 ± 22 mL/min/1.73 m², p = 0.02). In a sub-group with up to 10 years post-operative date, this trend was maintained. In patients with renal impairment, eGFR improved over 5 years (52 ± 2 to 68 ± 7 mL/min/1.73 m², p = 0.01). Remission of hypertension was greater after RYGB than LAGB at 1 year (32 vs. 16 %, p = 0.008) and at 5 years post-operatively (23 vs. 11 %, p = 0.02).

CONCLUSIONS

Bariatric surgery stabilizes eGFR post-operatively for at least 5 years. In a sub-group with renal impairment, eGFR is increased in the first post-operative year and this is maintained for up to 5 years. RYGB is an effective procedure in achieving blood pressure control.

The role of bariatric surgery in nonalcoholic fatty liver disease and nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) affects between 25% and 33% of the population, is more common in obese individuals, and is the most common cause of chronic liver disease in the United States. However, despite rising prevalence, effective treatments remain limited. Areas covered: We performed a literature search across multiple databases (Pubmed, Medline, etc.) to identify significant original research and review articles to provide an up-to-date and concise overview of disease pathogenesis and diagnostic evaluation and to expand on available treatment options with a specific focus on the potential role of bariatric surgery. Here we provide the most comprehensive review of bariatric surgery for the management of NAFLD, noting benefits from different procedures and multiple reports showing improvements in steatosis, inflammation and fibrosis over the duration of follow-up. Expert commentary: The morbidity of NAFLD is significant as it may become the most common indication for liver transplantation within the next 5 years. In addition to known benefits of weight loss and diabetes resolution, bariatric surgery has the potential to halt and reverse disease progression and future controlled trials should be performed to further define its benefit in the treatment of NAFLD in morbidly obese patients.

Adaptation of liver stiffness measurement depth in bariatric surgery candidates with suspected nonalcoholic fatty liver disease

BACKGROUND AND AIMS

A thick layer of subcutaneous adipose tissue may lead to an overestimation of liver stiffness by transient elastography. The aim of this study was to assess whether liver stiffness measurement (LSM) was overestimated using an XL probe in patients with severe obesity and, if so, to reprocess the data to the adapted depth to obtain the appropriate LSM (LSMa).

METHODS

A total of 152 obese patients prospectively underwent bariatric surgery and needle liver biopsy. Liver stiffness was measured by transient elastography 15 days before. To determine whether the LSM was overestimated, an expert operator retrospectively determined whether the skin-to-capsula distance was greater than 35 mm by analyzing the hyperechogenicity of ultrasound signals and the measured slope between 35 and 75 mm. In the case of an overestimation, a deeper measurement depth was selected to calculate the LSMa.

RESULTS

There was an overestimation of the LSM obtained between 35 and 75 mm in 76 patients (50%). Among these patients, the LSMa was obtained between 40 and 75 mm in 49 patients and between 45 and 80 mm in 27 patients. Only the percentage of steatosis was independently and positively correlated with LSM overestimation. The areas under receiver operating characteristic of LSMa was 0.82±0.04 for predicting fibrosis stage F3. The Obuchowski measure was 0.85±0.02.

CONCLUSION

The LSM was overestimated in severely obese patients obtained between 35 and 75 mm using an XL probe in 76 patients (50%), but LSM can be performed correctly in these patients after adapting the measurement depth to deeper beneath the patients' skin.

Roux-En Y Gastric Bypass Results in Long-Term Remission of Hepatocyte Apoptosis and Hepatic Histological Features of Non-alcoholic Steatohepatitis

The long-term effects of bariatric surgery on non-alcoholic steatohepatitis (NASH), focusing on liver injury and hepatocyte apoptosis, are not well-established. We here performed a longitudinal study with paired liver biopsies of nine morbidly obese women (median BMI: 42 [38.7; 45.1] kg/m²) with NASH with a median follow-up of 55 [44; 75] months after laparoscopic Roux-en-Y gastric bypass (LRYGB) surgery. LRYGB surgery was associated with significant weight loss (median BMI loss −13.7 [−16.4; −9.5] kg/m²), improved hepatic steatosis in all patients (55.5% with total resolution), and resolution of hepatic inflammation and hepatocyte ballooning in 100 and 88.8% of cases, respectively. Alanine aminotransferase levels dropped to normal values while hepatic activated cleaved caspase-3 levels strongly decreased after a median follow-up of 55 months. Hepatocyte apoptosis, as evaluated by serum caspase-generated keratin-18 fragment, improved within the first year following LRYGB and these improvements persisted for at least 55 months. LRYGB in morbidly obese patients with NASH is thus associated with a long-lasting beneficial impact on hepatic steatohepatitis and hepatocyte death.

Bariatric Surgery and Non-Alcoholic Fatty Liver Disease: a Systematic Review of Liver Biochemistry and Histology

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is becoming a leading cause of global liver disease that is associated with the rising prevalence of obesity worldwide. There is now increasing clinical and mechanistic evidence reporting on the metabolic and weight loss effects of bariatric surgery on improving NAFLD in obese patients.

OBJECTIVES

The aim of this paper was to quantify the effects of bariatric surgery on NAFLD by appraising the modulation between pre- and post-operative liver enzyme levels (as markers of liver injury) and liver histology.

METHODS

A systematic review of studies reporting pre-operative and post-operative liver enzymes or liver histology was done in obese patients with NAFLD undergoing bariatric surgery. Data were meta-analysed using random-effects modelling. Subgroup analysis, quality scoring and risk of bias were assessed.

RESULTS

Bariatric surgery is associated with a significant reduction in the weighted incidence of a number of histological features of NAFLD including steatosis (50.2 and 95 %CI of 35.5-65.0), fibrosis (11.9 and 95 %CI of 7.4-16.3 %), hepatocyte ballooning (67.7 and 95 %CI 56.9-78.5) and lobular inflammation (50.7 and 95 %CI 26.6-74.8 %). Surgery is also associated with a reduction in liver enzyme levels, with statistically significant reductions in ALT (11.36 u/l, 95 %CI 8.36-14.39), AST (3.91 u/l, 95 %CI 2.23-5.59), ALP (10.55 u/l, 95 %CI 4.40-16.70) and gamma-GT (18.39 u/l, 95 %CI 12.62-24.16). Heterogeneity in results was high.

CONCLUSIONS

Bariatric surgery is associated with a significant improvement in both histological and biochemical markers of NAFLD. Future studies must focus on higher levels of evidence to better identify the benefits of bariatric surgery on liver disease in order to enhance future treatment strategies in the management of NAFLD.

Improvements of Glucose and Lipid Metabolism After Jejuno-ileal Circuit Procedure in a Non-obese Diabetic Rat Model

BACKGROUND

In a recent study, we showed a jejuno-ileal circuit (JIC) procedure that effectively improved glucose homeostasis, but the intrinsic mechanism requires further studies. Furthermore, the role of JIC in lipid metabolism is also unknown. Given that adiposity aggravates insulin sensitivity, we hypothesize that the JIC procedure improves fat metabolism and thus further contributes to diabetic remission. The aim of this study was to investigate the effects of JIC surgery on lipid metabolism and glucose homeostasis in a non-obese diabetic rat model.

METHODS

Fourteen high-fat diet and low-dose streptozotocin-induced diabetic rats were randomly divided into JIC and sham-JIC groups. Body weight, food intake, glucose tolerance, insulin resistance, serum lipid parameters, glucagon-like peptide 1 (GLP-1), and adipose-derived hormones were measured. At 12 weeks postoperatively, the expressions of hepatic fatty acid synthase (FAS) and acetyl-CoA carboxylase (ACC) were measured by Western blot. The lipid content of liver was assessed by hematoxylin-eosin staining and Oil Red O staining. The enteroendocrine cells in the distal ileum were examined by immunohistochemical staining.

RESULTS

Relative to the sham group, the JIC rats exhibited significant improvements in glucose tolerance, insulin resistance, and dyslipidemia without weight loss, showing increased GLP-1 and adiponectin and decreased leptin. JIC also reduced the expression of FAS and ACC in the liver, exhibited improved hepatic fat content, and raised the levels of GLP-1 and chromogranin A in the distal gut.

CONCLUSIONS

JIC alleviated lipometabolic disorders in hyperglycemic rats, which may contribute to the amelioration of insulin sensitivity and glycemic control.

The diagnostic accuracy of transient elastography for the diagnosis of liver fibrosis in bariatric surgery candidates with suspected NAFLD

BACKGROUND

Severe obesity and metabolic syndrome have been implicated in the development of nonalcoholic fatty liver disease (NAFLD). We evaluated the diagnostic value of liver stiffness measurement (LSM), by transient elastography (FibroScan®) in bariatric surgery candidates with suspected NAFLD.

METHODS

A total of 100 prospectively included consecutive severely obese subjects underwent bariatric surgery with liver needle biopsy. LSM was performed in the 15 days preceding liver biopsy.

RESULTS

According to Kleiner's classification, 28 patients had no fibrosis, 50 had stage F1 fibrosis, 13 had stage F2 fibrosis, and nine had stage F3 fibrosis. LSMs were higher in patients with fibrosis stage F ≥2, than in patients with a fibrosis stage below F2 (p < 0.001). Fibrosis stage (p < 0.002), amount of steatosis (%) (p < 0.001), BMI (p < 0.02), and activity score (p = 0.027) were independently correlated with LSM. Homeostasis model assessment (HOMA) index was also significantly and independently correlated with LSM (p < 0.01). The area under the receiver operating characteristic curve (AUROC) generated by FibroScan® was 0.81 ± 0.05 for predicting fibrosis stage F ≥2 and 0.85 ± 0.04 for predicting F3 fibrosis. The decrease in LSM 1 year after bariatric surgery was significantly correlated with changes in HOMA index (r = 0.43, p = 0.01), but not with changes in BMI or weight.

CONCLUSION

FibroScan® allows the early diagnosis of fibrosis in severely obese patients. Our results also suggest that FibroScan® could identify a subgroup of NAFLD patients at high risk of progressive liver disease and that LSM could be used as a surrogate marker of insulin resistance. Further studies are required to evaluate the prognostic value of FibroScan®.

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

BACKGROUND & AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Bariatric Surgery Reduces Features of Nonalcoholic Steatohepatitis in Morbidly Obese Patients

BACKGROUND & AIMS

The effects of bariatric surgery in patients with nonalcoholic fatty liver disease (NASH) are not well established. We performed a prospective study to determine the biological and clinical effects of bariatric surgery in patients with NASH.

METHODS

From May 1994 through May 2013, one hundred and nine morbidly obese patients with biopsy-proven NASH underwent bariatric surgery at the University Hospital of Lille, France (the Lille Bariatric Cohort). Clinical, biological, and histologic data were collected before and 1 year after surgery.

RESULTS

One year after surgery, NASH had disappeared from 85% of the patients (95% confidence interval [CI]: 75.8%-92.2%). Compared with before surgery, patients had significant reductions in mean ± SD body mass index (BMI, from 49.3 ± 8.2 to 37.4 ± 7) and level of alanine aminotransferase (from 52.1 ± 25.7 IU/L to 25.1 ± 20 IU/L); mean levels of γ-glutamyltransferases were reduced from 51 IU/L before surgery (interquartile range [IQR], 34-87 IU/L) to 23 IU/L afterward (IQR, 14-33 IU/L) and mean insulin resistance index values were reduced from 3.6 ± 0.5 to 2.9 ± 0.5 (P < .01 for each comparison). NASH disappeared from a higher proportion of patients with mild NASH before surgery (94%) than severe NASH (70%) (P < .05) according to Brunt score. In histologic analysis, steatosis was detected in 60% of the tissue before surgery (IQR, 40%-80%) but only 10% 1 year after surgery (IQR, 2.5%-21.3%); the mean nonalcoholic fatty liver disease score was reduced from 5 (IQR, 4-5) to 1 (IQR, 1-2) (each P < .001). Hepatocellular ballooning was reduced in 84.2% of samples (n = 69; 95% CI: 74.4-91.3) and lobular inflammation in 67.1% (n = 55; 95% CI: 55.8-77.1). According to Metavir scores, fibrosis was reduced in 33.8% of patients (95% CI: 23.6%-45.2%). Patients whose NASH persisted 1 year after surgery (n = 12) had lost significantly less weight (change in BMI, 9.1 ± 1.5) than those without NASH (change in BMI, 12.3 ± 0.6) (P = .005). Patients who underwent laparoscopic gastric banding lost less weight (change in BMI, 6.4 ± 0.7) than those who underwent gastric bypass (change in BMI, 14.0 ± 0.5) (P < .0001), and a higher proportion had persistent NASH (30.4% vs 7.6% of those with gastric bypass; P = .015).

CONCLUSIONS

Bariatric surgery induced the disappearance of NASH from nearly 85% of patients and reduced the pathologic features of the disease after 1 year of follow-up. It could be a therapeutic option for appropriate morbidly obese patients with NASH who do not respond to lifestyle modifications. More studies are needed to determine the long-term effects of bariatric surgery in morbidly obese patients with NASH.