Bariatric-metabolic surgery versus lifestyle intervention plus best medical care in non-alcoholic steatohepatitis (BRAVES): a multicentre, open-label, randomised trial.

BACKGROUND: Observational studies suggest that bariatric-metabolic surgery might greatly improve non-alcoholic steatohepatitis (NASH). However, the efficacy of surgery on NASH has not yet been compared with the effects of lifestyle interventions and medical therapy in a randomised trial. METHODS: We did a multicentre, open-label, randomised trial at three major hospitals in Rome, Italy. We included participants aged 25-70 years with obesity (BMI 30-55 kg/m2), with or without type 2 diabetes, with histologically confirmed NASH. We randomly assigned (1:1:1) participants to lifestyle modification plus best medical care, Roux-en-Y gastric bypass, or sleeve gastrectomy. The primary endpoint of the study was histological resolution of NASH without worsening of fibrosis at 1-year follow-up. This study is registered at ClinicalTrials.gov, NCT03524365. FINDINGS: Between April 15, 2019, and June 21, 2021, we biopsy screened 431 participants; of these, 103 (24%) did not have histological NASH and 40 (9%) declined to participate. We randomly assigned 288 (67%) participants with biopsy-proven NASH to lifestyle modification plus best medical care (n=96 [33%]), Roux-en-Y gastric bypass (n=96 [33%]), or sleeve gastrectomy (n=96 [33%]). In the intention-to-treat analysis, the percentage of participants who met the primary endpoint was significantly higher in the Roux-en-Y gastric bypass group (54 [56%]) and sleeve gastrectomy group (55 [57%]) compared with lifestyle modification (15 [16%]; p<0·0001). The calculated probability of NASH resolution was 3·60 times greater (95% CI 2·19-5·92; p<0·0001) in the Roux-en-Y gastric bypass group and 3·67 times greater (2·23-6·02; p<0·0001) in the sleeve gastrectomy group compared with in the lifestyle modification group. In the per protocol analysis (236 [82%] participants who completed the trial), the primary endpoint was met in 54 (70%) of 77 participants in the Roux-en-Y gastric bypass group and 55 (70%) of 79 participants in the sleeve gastrectomy group, compared with 15 (19%) of 80 in the lifestyle modification group (p<0·0001). No deaths or life-threatening complications were reported in this study. Severe adverse events occurred in ten (6%) participants who had bariatric-metabolic surgery, but these participants did not require re-operations and severe adverse events were resolved with medical or endoscopic management. INTERPRETATION: Bariatric-metabolic surgery is more effective than lifestyle interventions and optimised medical therapy in the treatment of NASH. FUNDING: Fondazione Policlinico Universitario A Gemelli, Policlinico Universitario Umberto I and S Camillo Hospital, Rome, Italy.

Accurate liquid biopsy for the diagnosis of non-alcoholic steatohepatitis and liver fibrosis.

OBJECTIVE: Clinical diagnosis and approval of new medications for non-alcoholic steatohepatitis (NASH) require invasive liver biopsies. The aim of our study was to identify non-invasive biomarkers of NASH and/or liver fibrosis. DESIGN: This multicentre study includes 250 patients (discovery cohort, n=100 subjects (Bariatric Surgery Versus Non-alcoholic Steato-hepatitis - BRAVES trial); validation cohort, n=150 (Liquid Biopsy for NASH and Liver Fibrosis - LIBRA trial)) with histologically proven non-alcoholic fatty liver (NAFL) or NASH with or without fibrosis. Proteomics was performed in monocytes and hepatic stellate cells (HSCs) with iTRAQ-nano- Liquid Chromatography - Mass Spectrometry/Mass Spectrometry (LC-MS/MS), while flow cytometry measured perilipin-2 (PLIN2) and RAB14 in peripheral blood CD14+CD16- monocytes. Neural network classifiers were used to predict presence/absence of NASH and NASH stages. Logistic bootstrap-based regression was used to measure the accuracy of predicting liver fibrosis. RESULTS: The algorithm for NASH using PLIN2 mean florescence intensity (MFI) combined with waist circumference, triglyceride, alanine aminotransferase (ALT) and presence/absence of diabetes as covariates had an accuracy of 93% in the discovery cohort and of 92% in the validation cohort. Sensitivity and specificity were 95% and 90% in the discovery cohort and 88% and 100% in the validation cohort, respectively.The area under the receiver operating characteristic (AUROC) for NAS level prediction ranged from 83.7% (CI 75.6% to 91.8%) in the discovery cohort to 97.8% (CI 95.8% to 99.8%) in the validation cohort.The algorithm including RAB14 MFI, age, waist circumference, high-density lipoprotein cholesterol, plasma glucose and ALT levels as covariates to predict the presence of liver fibrosis yielded an AUROC of 95.9% (CI 87.9% to 100%) in the discovery cohort and 99.3% (CI 98.1% to 100%) in the validation cohort, respectively. Accuracy was 99.25%, sensitivity 100% and specificity 95.8% in the discovery cohort and 97.6%, 99% and 89.6% in the validation cohort. This novel biomarker was superior to currently used FIB4, non-alcoholic fatty liver disease fibrosis score and aspartate aminotransferase (AST)-to-platelet ratio and was comparable to ultrasound two-dimensional shear wave elastography. CONCLUSIONS: The proposed novel liquid biopsy is accurate, sensitive and specific in diagnosing the presence and severity of NASH or liver fibrosis and is more reliable than currently used biomarkers. CLINICAL TRIALS: Discovery multicentre cohort: Bariatric Surgery versus Non-Alcoholic Steatohepatitis, BRAVES, ClinicalTrials.gov identifier: NCT03524365.Validation multicentre cohort: Liquid Biopsy for NASH and Fibrosis, LIBRA, ClinicalTrials.gov identifier: NCT04677101.

Small intestinal metabolism is central to whole-body insulin resistance.

OBJECTIVE: To assess the role of jejunum in insulin resistance in humans and in experimental animals. DESIGN: Twenty-four subjects undergoing biliopancreatic diversion (BPD) or Roux-en-Y gastric bypass (RYGB) were enrolled. Insulin sensitivity was measured at baseline and at 1 week after surgery using oral glucose minimal model.We excluded the jejunum from intestinal continuity in pigs and created a jejunal loop with its vascular and nerve supply intact accessible from two cutaneous stomas, and reconnected the bowel with an end-to-end anastomosis. Glucose stable isotopes were given in the stomach or in the jejunal loop.In vitro studies using primary porcine and human hepatocytes or myoblasts tested the effects of plasma on gluconeogenesis or glucose uptake and insulin signalling. RESULTS: Whole-body insulin sensitivity (SI∙104: 0.54±0.12 before vs 0.82±0.11 after BPD, p=0.024 and 0.41±0.09 before vs 0.65±0.09/pM/min after RYGB, p=not significant) and Glucose Disposition Index increased only after BPD. In pigs, insulin sensitivity was significantly lower when glucose was administered in the jejunal loop than in the stomach (glucose rate of disappearance (Rd) area under the curve (AUC)/insulin AUC∙10: 1.82±0.31 vs 2.96±0.33 mmol/pM/min, p=0.0017).Metabolomics showed a similar pattern before surgery and during jejunal-loop stimulation, pointing to a higher expression of gluconeogenetic substrates, a metabolic signature of impaired insulin sensitivity.A greater hepatocyte phosphoenolpyruvate-carboxykinase and glucose-6-phosphatase gene expression was elicited with plasma from porcine jejunal loop or before surgery compared with plasma from jejunectomy in pigs or jejunal bypass in humans.Stimulation of myoblasts with plasma from porcine jejunal loop or before surgery reduced glucose uptake, Ser473-Akt phosphorylation and GLUT4 expression compared with plasma obtained during gastric glucose administration after jejunectomy in pigs or after jejunal bypass in humans. CONCLUSION: Proximal gut plays a crucial role in controlling insulin sensitivity through a distinctive metabolic signature involving hepatic gluconeogenesis and muscle insulin resistance. Bypassing the jejunum is beneficial in terms of insulin-mediated glucose disposal in obesity. TRIAL REGISTRATION NUMBER: NCT03111953.

Duodenal-jejunal bypass improves nonalcoholic fatty liver disease independently of weight loss in rodents with diet-induced obesity.

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of liver-related mortality. NAFLD is associated with obesity, hepatic fat accumulation, and insulin resistance, all of which contribute to its pathophysiology. Weight-loss is the main therapy for NAFLD, and metabolic surgery is the most effective treatment for morbid obesity and its metabolic comorbidities. Although has been reported that Roux-en-Y gastric bypass can reverse NAFLD, it is unclear whether such effects result from reduced weight, from a lower calorie-intake, or from the direct influence of surgery on mechanisms contributing to NAFLD. We aimed to investigate whether gastrointestinal (GI) bypass surgery could induce direct effects on hepatic fat accumulation and insulin resistance, independently of weight reduction. Twenty Wistar rats on a high-fat diet underwent duodenal-jejunal-bypass (DJB) or sham operation and were pair fed (PF) for 15 wk after surgery to obtain a matched weight. Outcome measures include ectopic fat deposition, expression of genes and proteins involved in fat metabolism, insulin-signaling, and gluconeogenesis in liver and muscle. Despite no differences in body weight and calorie intake, DJB showed lower ectopic fat accumulation, improved peripheral and hepatic insulin sensitivity, and enhanced lipid droplet degradation. In both tissues, DJB increased insulin signaling, whereas hepatic key enzymes involved in gluconeogenesis and de novo lipogenesis were decreased. These findings suggest that DJB can reverse, independently of weight loss, ectopic fat deposition and insulin resistance, two features of NAFLD that share a mutual pathway, in which perilipin-2 (PLIN2) seems to be the main player, supporting further investigation into strategies that target the gut to treat metabolic liver diseases.NEW & NOTEWORTHY Our findings suggest that duodenal-jejunal bypass can reverse, independently of weight loss, ectopic fat deposition and insulin resistance, two features of nonalcoholic fatty liver disease that share a mutual pathway, in which perilipin-2 seems to be the main player. Our study supports further investigation into the role of proximal small intestine exclusion in the pathophysiology of nonalcoholic fatty liver disease to uncover less invasive treatments that mimic the effects of metabolic surgery and aims to prevent and treat metabolic liver disease.

Matrix metalloproteinase-9 might affect adaptive immunity in non-ST segment elevation acute coronary syndromes by increasing CD31 cleavage on CD4+ T-cells.

Aims: In patients with acute coronary syndrome (ACS), the higher activity of effector T-cells suggests that mechanisms involving adaptive immunity dysregulation might play a role in coronary instability. The shedding of the functional CD31 domain 1-5 leads to uncontrolled lymphocyte activation. In experimental models, matrix metalloproteinase-9 (MMP-9) has been implicated in endothelial CD31 cleavage. Interestingly, higher serum levels of MMP-9 have been observed in ACS. We aim to investigate the mechanisms underlying CD31 dysregulation in ACS. Methods and results: To assess CD31 cleavage on CD4+ T-cells, we analysed by flow cytometry CD4+ T-cells of 30 ACS, 25 stable angina (SA) patients, and 28 controls (CTRL) using two different CD31 antibodies that specifically recognize domain 1-5 or the non-functional membrane-proximal domain 6. The ratio between the domains was significantly lower in ACS than in SA and CTRL (P = 0.002 ACS vs. SA; P = 0.002 ACS vs. CTRL). After stimulation with anti-CD3/CD28, the 1-5/6 domain ratio was significantly lower in ACS than in SA (P = 0.005). ELISA of supernatants obtained from T-cell receptor-stimulated CD4+ T-cells showed higher production of MMP-9 in ACS than in SA (P < 0.001). CD31 domain 1-5 expression in activated CD4+ T-cells from ACS patients increased after treatment with a specific MMP-9 inhibitor (P = 0.042). Conclusion: Our study suggest that enhanced MMP-9 release plays a key role in determining the cleavage and shedding of the functional CD31 domain 1-5 in CD4+ T-cells of ACS patients. This mechanism might represent an important therapeutic target to modulate T-cell dysregulation in ACS.

Incretin hormones, obesity and gut microbiota.

Over the past 40 years, the prevalence of obesity has risen dramatically, reaching epidemic proportions. By 2030 the number of people affected by obesity will reach 1.12 billion worldwide. Gastrointestinal hormones, namely incretins, play a vital role in the pathogenesis of obesity and its comorbidities. GIP (glucose-dependent insulinotropic polypeptide) and GLP-1 (glucagon-like peptide-1), which are secreted from the intestine after nutrient intake and stimulate insulin secretion from pancreatic ß cells, influence lipid metabolism, gastric empting, appetite and body weight. The gut microbiota plays an important role in various metabolic conditions, including obesity and type 2 diabetes and influences host metabolism through the interaction with enteroendocrine cells that modulate incretins secretion. Gut microbiota metabolites, such as short-chain fatty acids (SCFAs) and indole, directly stimulate the release of incretins from colonic enteroendocrine cells influencing host satiety and food intake. Moreover, bariatric surgery and incretin-based therapies are associated with increase gut bacterial richness and diversity. Understanding the role of incretins, gut microbiota, and their metabolites in regulating metabolic processes is crucial to develop effective strategies for the management of obesity and its associated comorbidities.

Intestinal heat shock proteins in metabolic syndrome: Novel mediators of obesity and its comorbidities resolution after metabolic surgery.

Over the past 40 years, the prevalence of obesity has risen dramatically, reaching epidemic proportions. Metabolic surgery has proven to be highly effective in treating obesity, leading to significant improvements or complete resolution of obesity-related comorbidities. Research conducted in both animals and humans suggests that the metabolic benefits achieved through metabolic surgery cannot be solely attributed to weight loss. Indeed, there has been an increasing recognition of intestinal inflammation as a novel factor influencing obesity. The gastrointestinal tract is continuously exposed to dietary components, particularly diets rich in saturated fats, which are known to contribute to obesity. It is now widely accepted that heat shock proteins can be released from various cells including intestinal epithelial cells and act as proinflammatory signals. Several studies have shown that circulating levels of glucose-regulated protein 78 (GRP78) are increased in subjects with obesity and correlate with the severity of the disease. Moreover, mice with a partial knockout of GRP78 are protected from diet-induced obesity. In this review, we discuss the role of GRP78 in the development of obesity. Several evidence suggests that GRP78 can influence adipogenesis, lipid droplets stabilization, insulin resistance, and liver steatosis. We also provide an update on GRP78 regulation following metabolic surgery, focusing on the bypass of the small intestine as a key factor for GRP78 secretion. Finally, we discuss the potential role of monoclonal antibodies against GRP78 as a treatment for obesity.

The first external validation of the Dallas steatosis index in biopsy-proven Non-alcoholic fatty liver Disease: A multicenter study.

AIMS: A new non-invasive tool (NIT) for non-alcoholic fatty liver disease (NAFLD) proposed in 2022 by the multi-ethnic Dallas Heart Study, i.e. the Dallas Steatosis Index (DSI), was validated herein using for the first time the gold standard i.e. liver biopsy-proven NAFLD. METHODS: This is a multicenter study based on samples and data from two Gastroenterology-Hepatology Clinics (Greece and Australia) and one Bariatric-Metabolic Surgery Clinic (Italy). Overall, n = 455 patients with biopsy-proven NAFLD (n = 374) and biopsy-proven controls (n = 81) were recruited. RESULTS: The ability of DSI to correctly classify participants as NAFLD or controls was very good, reaching an Area Under the Curve (AUC) = 0.887. The cut-off point that could best differentiate the presence vs. absence of NAFLD corresponded to DSI = 0.0 (risk threshold: 50% | Sensitivity: 0.88; Positive Predictive Value (PPV): 93.0%; F1-score = 0.91). DSI demonstrated significantly better performance characteristics than other liver steatosis indexes. Decision curve analysis revealed that the benefit of DSI as a marker to indicate the need for invasive liver assessment was confirmed only when higher DSI values, i.e. ≥ 1.4, were used as risk thresholds. DSI performance to differentiate disease progression was inadequate (all AUCs < 0.700). CONCLUSIONS: DSI is more useful for disease screening (NAFLD vs. controls) than to differentiate diseases stages or progression. The value of any inclusion of DSI to guidelines needs to be further studied.

Long-term Outcomes of Transoral Outlet Reduction (TORe) for Dumping Syndrome and Weight Regain After Roux-en-Y Gastric Bypass.

BACKGROUND: Both weight regain and dumping syndrome (DS) after Roux-en-Y gastric bypass (RYGB) have been related to the dilation of gastro-jejunal anastomosis. The aim of this study is to assess the safety and long-term efficacy of endoscopic transoral outlet reduction (TORe) for DS and/or weight regain after RYBG. MATERIALS AND METHODS: A retrospective analysis was performed on a prospective database. Sigstad's score, early and late Arts Dumping Score (ADS) questionnaires, absolute weight loss (AWL), percentage of total body weight loss (%TBWL), and percentage of excess weight loss (%EWL) were assessed at baseline and at 6, 12, and 24 months after TORe. RESULTS: Eighty-seven patients (median age 46 years, 79% female) underwent TORe. The median baseline BMI was 36.2 kg/m2. Out of 87 patients, 58 were classified as "dumpers" due to Sigstad's score ≥ 7. The resolution rate of DS (Sigstad's score < 7) was 68.9%, 66.7%, and 57.2% at 6, 12, and 24 months after TORe, respectively. A significant decrease in Sigstad's score as well as in early and late ADS questionnaires was observed (p < 0.001). The median Sigstad's score dropped from 15 (11-8.5) pre-operatively to 2 (0-12) at 24 months. The %TBWL was 10.5%, 9.9%, and 8.1% at 6, 12, and 24 months, respectively. Further, "dumpers" with resolution of DS showed better weight loss results compared with those with persistent DS (p < 0.001). The only adverse event observed was a perigastric fluid collection successfully managed conservatively. CONCLUSION: TORe is a minimally invasive treatment for DS and/or weight regain after RYGB, with evidence of long-term efficacy.

The early reduction of left ventricular mass after sleeve gastrectomy depends on the fall of branched-chain amino acid circulating levels.

INTRODUCTION: Body-mass index is a major determinant of left-ventricular-mass (LVM). Bariatric-metabolic surgery (BMS) reduces cardiovascular mortality. Its mechanism of action, however, often encompasses a weight-dependent effect. In this translational study, we aimed at investigating the mechanisms by which BMS leads to LVM reduction and functional improvement. METHODS: Twenty patients (45.2 ± 8.5years) were studied with echocardiography at baseline and at 1,6,12 and 48 months after sleeve-gastrectomy (SG). Ten Wistar rats aged 10-weeks received high-fat diet ad libitum for 10 weeks before and 4 weeks after SG or sham-operation. An oral-glucose-tolerance-test was performed to measure whole-body insulin-sensitivity. Plasma metabolomics was analysed in both human and rodent samples. RNA quantitative Real-Time PCR and western blots were performed in rodent heart biopsies. The best-fitted partial-least-square discriminant-analysis model was used to explore the variable importance in the projection score of all metabolites. FINDINGS: Echocardiographic LVM (-12%,-23%,-28% and -43% at 1,6,12 and 48 months, respectively) and epicardial fat decreased overtime after SG in humans while insulin-sensitivity improved. In rats, SG significantly reduced LVM and epicardial fat, enhanced ejection-fraction and improved insulin-sensitivity compared to sham-operation. Metabolomics showed a progressive decline of plasma branched-chain amino-acids (BCAA), alanine, lactate, 3-OH-butyrate, acetoacetate, creatine and creatinine levels in both humans and rodents. Hearts of SG rats had a more efficient BCAA, glucose and fatty-acid metabolism and insulin signaling than sham-operation. BCAAs in cardiomyocyte culture-medium stimulated lipogenic gene transcription and reduced mRNA levels of key mitochondrial ß-oxidation enzymes promoting lipid droplet accumulation and glycolysis. INTERPRETATION: After SG a prompt and sustained decrease of the LVM, epicardial fat and insulin resistance was found. Animal and in vitro studies showed that SG improves cardiac BCAA metabolism with consequent amelioration of fat oxidation and insulin signaling translating into decreased intra-myocytic fat accumulation and reduced lipotoxicity. FUNDING: This work was supported by the University of Rome Sapienza.

Upper gut heat shock proteins HSP70 and GRP78 promote insulin resistance, hyperglycemia, and non-alcoholic steatohepatitis.

A high-fat diet increases the risk of insulin resistance, type-2 diabetes, and non-alcoholic steato-hepatitis. Here we identified two heat-shock proteins, Heat-Shock-Protein70 and Glucose-Regulated Protein78, which are increased in the jejunum of rats on a high-fat diet. We demonstrated a causal link between these proteins and hepatic and whole-body insulin-resistance, as well as the metabolic response to bariatric/metabolic surgery. Long-term continuous infusion of Heat-Shock-Protein70 and Glucose-Regulated Protein78 caused insulin-resistance, hyperglycemia, and non-alcoholic steato-hepatitis in rats on a chow diet, while in rats on a high-fat diet continuous infusion of monoclonal antibodies reversed these phenotypes, mimicking metabolic surgery. Infusion of these proteins or their antibodies was also associated with shifts in fecal microbiota composition. Serum levels of Heat-Shock-Protein70 and Glucose-Regulated Protein78were elevated in patients with non-alcoholic steato-hepatitis, but decreased following metabolic surgery. Understanding the intestinal regulation of metabolism may provide options to reverse metabolic diseases.

Prevalence and predictors of non-alcoholic steatohepatitis in subjects with morbid obesity and with or without type 2 diabetes.

AIM: To investigate the prevalence of biopsy-proven non-alcoholic steatohepatitis (NASH) in a cohort of patients with morbid obesity and with or without type 2 diabetes (T2D) and to find non-invasive predictors of NASH severity. METHODS: We evaluated a cohort of 412 subjects (age 19-67 years, body mass index-BMI: 44.98 kg/m2), who underwent fine-needle liver biopsy during bariatric surgery. Thirty-six percent of the subjects were affected by T2D. Liver biopsies were classified according to the Kleiner's NAFLD Activity Score (NAS). NAFLD Fibrosis Score (NFS), AST/ALT ratio, AST to Platelet ratio (APRI), fibrosis-4 score (FIB4) were calculated. A neural network analysis (NNA) was run to predict NASH severity. RESULTS: The prevalence of biopsy-proven NASH was 63% and 78% in subjects with obesity and without or with T2D, respectively. T2D doubled the risk of NASH [OR 2.079 (95% IC=1.31-3.29)]. The prevalence of NAFL increased with the increase of BMI, while there was an inverse correlation between BMI and NASH (r=-0.145 p=0.003). Only mild liver fibrosis was observed. HOMA-IR was positively associated with hepatocyte ballooning (r=0.208, p<0.0001) and fibrosis (r=0.159, p=0.008). The NNA highlighted a specificity of 77.3% using HDL-cholesterol, BMI, and HOMA-IR as main determinants of NASH. CONCLUSIONS: Our data show a higher prevalence of NASH in patients with morbid obesity than reported in the literature and the pivotal role of T2D among the risk factors for NASH development. However, the inverse correlation observed between BMI and biopsy-proven NASH suggests that over a certain threshold adiposity can be somewhat protective against liver damage. Our model predicts NASH presence with high specificity, thus helping identifying subjects who should promptly undergo liver biopsy.

GLUT-1/PKM2 loop dysregulation in patients with non-ST-segment elevation myocardial infarction promotes metainflammation.

AIM: The functional capacity of the immune cells is strongly dependent on their metabolic state and inflammatory responses are characterized by a greater use of glucose in immune cells. This study is aimed to establish the role of glucose metabolism and its players [glucose transporter-1 (GLUT-1) and pyruvate kinase isozyme M2 (PKM2)] in the dysregulation of adaptive immunity and inflammation observed in patients with non-ST-segment elevation myocardial infarction (NSTEMI). METHODS AND RESULTS: We enrolled 248 patients allocated to three groups: NSTEMI patients, chronic coronary syndromes (CCS) patients, healthy subjects (HS). NSTEMI patients showed higher expression of GLUT-1 and an enhanced glucose uptake in T cells as compared to CCS patients (p < 0.0001; p = 0.0101, respectively) and HS (p = 0.0071; p = 0.0122, respectively). PKM2 had a prevalent nuclear localization in T lymphocytes in NSTEMI (p = 0.0005 for nuclear versus cytoplasm localization), while in CCS and HS was equally distributed in both compartments. In addition, the nuclear fraction of PKM2 was significantly higher in NSTEMI compared to HS (p = 0.0023). In NSTEMI patients, treatment with Shikonin and Fasentin, which inhibits PKM2 enzyme activity and GLUT-1 mediated glucose internalization, respectively, led to a significant reduction in GLUT-1 expression along with the downregulation of pro-inflammatory cytokine expression. CONCLUSIONS: NSTEMI patients exhibit dysregulation of the GLUT-1/PKM2 metabolic loop characterized by nuclear translocation of PKM2, where it acts as a transcription regulator of pro-inflammatory genes. This detrimental loop might represent a new therapeutic target for personalized medicine.

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 ±â€…1.72 at baseline to 1.73 ±â€…1.08 (P < .001) after BPD, and the Matsuda index improved from 2.66 ±â€…1.79 to 4.73 ±â€…3.05 (P < .001). The lipid profile normalized (total cholesterol from 4.75 ±â€…1.18 to 3.32 ±â€…0.77 mmol/L, P < .001; low-density lipoprotein cholesterol from 2.92 ±â€…0.91 to 1.60 ±â€…0.51 mmol/L, P = .0001; high-density lipoprotein cholesterol from 0.97 ±â€…0.33 to 1.10 ±â€…0.35 mmol/L, P = .023; triglycerides from 2.52 ±â€…1.6 to 1.47 ±â€…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.

The jejunum is the key factor in insulin resistance.

BACKGROUND: Biliopancreatic diversion (BPD) is more effective than Roux-en-Y gastric bypass (RYGB) on both insulin resistance and diabetes. OBJECTIVES: Because the major difference between the 2 procedures resides in the length of jejunal bypass, we investigated the role of the jejunum in insulin resistance. SETTING: University hospital in Italy. METHODS: Insulin sensitivity (IS) and secretion were measured before and 4 weeks after RYGB or BPD in 16 patients. A translational study was also conducted in 6 pigs, by isolating a jejunal loop with its vascular and nerve supply (Thiry-Vella loop [TVL]). TVL was doubly stomatized and bowel continuity restored by a side-to-side jejuno-jejunostomy. At baseline and 4 weeks postoperatively a glucose bolus was injected either in the stomach or in the TVL. Whole-body IS and jejunal heat shock proteins (HSPs) were measured. Primary porcine hepatocyte cultures were incubated with plasma or individual HSPs. RESULTS: Whole-body IS increased from 353.5 ± 26.7 to 442.0 ± 37.4 (P < .05) after RYGB and from 312.4 ± 14.9 to 441.2 ± 15.9 mL/m-2/min-1 (P < .001) after BPD. Hepatic IS was unchanged after RYGB, while it increased from .3 ± .01 to .4 ± .1 (µM/pM) - 1 (P < .01) after BPD. Total insulin secretion rate remained unchanged after RYGB but decreased (from 58.3 ± 23.6 to 33.1 ± 7.8 nmol/m-2, P < .05) after BPD. Jejunectomy in pigs enhanced IS (.3 ± .01 versus .2 ± .01 mM/pM, P < .001), while injection of glucose into TVL reduced it (.1 ± .01 versus .3 ± .01 mM/pM, P < .0001). The jejunum secreted HSPs, Hsp70, and GRP78, which impaired insulin signaling in hepatocyte cultures. CONCLUSIONS: This study shows that jejunal bypass in both humans and pigs improves IS. Injection of glucose into the TVL in pigs determines insulin resistance. In response to glucose, the jejunum secretes HSPs that impair insulin signaling.

Publisher Correction: New insight into the mechanisms of ectopic fat deposition improvement after bariatric surgery.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

New insight into the mechanisms of ectopic fat deposition improvement after bariatric surgery.

Non-alcoholic fatty-liver disease (NAFLD) is frequent in obese patients and represents a major risk factor for the development of diabetes and its complications. Bariatric surgery reverses the hepatic features of NAFLD. However, its mechanism of action remains elusive. We performed a comprehensive analysis of the mechanism leading to the improvement of NAFLD and insulin resistance in both obese rodents and humans following sleeve-gastrectomy (SG). SG improved insulin sensitivity and reduced hepatic and monocyte fat accumulation. Importantly, fat accumulation in monocytes was well comparable to that in hepatocytes, suggesting that Plin2 levels in monocytes might be a non-invasive marker for the diagnosis of NAFLD. Both in vitro and in vivo studies demonstrated an effective metabolic regeneration of liver function and insulin sensitivity. Specifically, SG improved NAFLD significantly by enhancing AMP-activated protein kinase (AMPK) phosphorylation and chaperone-mediated autophagy (CMA) that translate into the removal of Plin2 coating lipid droplets. This led to an increase in lipolysis and specific amelioration of hepatic insulin resistance. Elucidating the mechanism of impaired liver metabolism in obese subjects will help to design new strategies for the prevention and treatment of NAFLD.

Simulation of gastric bypass effects on glucose metabolism and non-alcoholic fatty liver disease with the Sleeveballoon device.

BACKGROUND: Gastric bypass surgery is a very effective treatment of obesity and type 2 diabetes. However, very few eligible patients are offered surgery. Some patients also prefer less invasive approaches. We aimed to study the effects of the Sleeveballoon - a new device combining an intragastric balloon with a connecting sleeve, which covers the duodenal and proximal jejunal mucosa - on insulin sensitivity, glycemic control, body weight and body fat distribution. METHODS: We compared the effects of Sleeveballoon, Roux-en-Y Gastric-Bypass (RYGB) and sham-operation in 30 high-fat diet (HFD) fed Wistar rats. Whole body and hepatic insulin sensitivity and insulin signaling were studied. Transthoracic echocardiography was performed using a Vevo 2100 system (FUJIFILM VisualSonics Inc., Canada). Gastric emptying was measured using gastrografin. FINDINGS: Hepatic (P = .023) and whole-body (P = .011) insulin sensitivity improved in the Sleeveballoon and RYGB groups compared with sham-operated rats. Body weight reduced in both Sleeveballoon and RYGB groups in comparison to the sham-operated group (503.1 ±â€¯8.9 vs. 614.4 ±â€¯20.6 g, P = .006 and 490.0 ±â€¯17.7 vs. 614.4 ±â€¯20.6 g, P = .006, respectively). Ectopic fat deposition was drastically reduced while glycogen content was increased in both liver and skeletal muscle. Gastric emptying (T1/2) was longer (157.7 ±â€¯29.2 min, P = .007) in the Sleeveballoon than in sham-operated rats (97.1 ±â€¯26.3 min), but shorter in RYGB (3.5 ±â€¯1.1 min, P < .0001). Cardiac function was better in Sleeveballoon and RYGB versus sham-operated rats. INTERPRETATION: The Sleeveballoon reduces peripheral and hepatic insulin resistance, glycaemia, body weight and ectopic fat deposition to a similar level as RYGB, although the contribution of gastric emptying to blood glucose reduction is different.

Metabolic surgery improves insulin resistance through the reduction of gut-secreted heat shock proteins.

Metabolic surgery improves insulin resistance and is associated with the remission of type 2 diabetes, but the mechanisms involved remain unknown. We find that human jejunal mucosa secretes heat shock proteins (HSPs) in vitro, in particular HSP70 and GRP78. Circulating levels of HSP70 are higher in people resistant to insulin, compared to the healthy and normalize after duodenal-jejunal bypass. Insulin sensitivity negatively correlates with the plasma level of HSP70, while body mass index does not. A high-energy diet increases the circulating levels of HSP70 and insulin resistance. HSP70 stimulates the accumulation of lipid droplets and inhibits Ser473 phosphorylation of Akt and glucose uptake in immortalized liver cells and peripheral blood cells. Serum depleted of HSPs, as well as the serum from the insulin-resistant people subjected to a duodenal-jejunal bypass, reverse these features, identifying gut-secreted HSPs as possible causes of insulin resistance. Duodenal-jejunal bypass might reduce the secretion of HSPs either by shortening the food transit or by decreasing the fat stimulation of endocrine cells.