Post-Bariatric Hypoglycemia: an Impaired Metabolic Response to a Meal.

AIMS/HYPOTHESIS: Post-bariatric hypoglycemia (PBH) is caused by postprandial hyperinsulinemia, due to anatomical alterations and changes in post-prandial metabolism after bariatric surgery. The mechanisms underlying the failing regulatory and compensatory systems are unclear. In this study, we investigated the differences in post-prandial hormones and metabolic profiles between patients with and without PBH. METHODS: We performed a mixed meal test (MMT) in 63 subjects before and 1 year after Roux-en-Y gastric bypass (RYGB) surgery. Blood was withdrawn at 0, 10, 20, 30, 60, and 120 min after ingestion of a standardized meal. Glucose, insulin, GLP-1, FGF-19, and FGF-21 were measured and untargeted metabolomics analysis was performed on blood plasma to analyze which hormonal and metabolic systems were altered between patients with and without PBH. RESULTS: Out of 63, a total of 21 subjects (33%) subjects developed PBH (glucose < 3.1 mmol/L) after surgery. Decreased glucose and increased insulin excursions during MMT were seen in PBH (p < 0.05). GLP-1, FGF-19, and FGF-21 were elevated after surgery (p < 0.001), but did not differ between PBH and non-PBH groups. We identified 20 metabolites possibly involved in carbohydrate metabolism which differed between the two groups, including increased carnitine and acylcholines in PBH. CONCLUSION: Overall, 33% of the subjects developed PBH 1 year after RYGB surgery. While GLP-1, FGF-19, and FGF-21 were similar in PBH and non-PBH patients, metabolomics analysis revealed changes in carnitine and acyclcholines that are possibly involved in energy metabolism, which may play a role in the occurrence of PBH.

An integrated analysis of bile acid metabolism in humans with severe obesity.

BACKGROUND AND AIMS: Bile acids (BA) are vital regulators of metabolism. BAs are AQ6 secreted in the small intestine, reabsorbed, and transported back to the liver, where they can modulate metabolic functions. There is a paucity of data regarding the portal BA composition in humans. This study aimed to address this knowledge gap by investigating portal BA composition and the relation with peripheral and fecal BA dynamics in conjunction with the gut microbiome. APPROACH AND RESULTS: Thirty-three individuals from the BARIA cohort were included. Portal plasma, peripheral plasma, and feces were collected. BA and C4 levels were measured employing mass spectrometry. FGF19 was measured using ELISA. Gut microbiota composition was determined through metagenomics analysis on stool samples. Considerable diversity in the portal BA composition was observed. The majority (n = 26) of individuals had a 9-fold higher portal than peripheral BA concentration. In contrast, 8 individuals showed lower portal BA concentration compared with peripheral and had higher levels of unconjugated and secondary BA in this compartment, suggesting more distal origin. The altered portal BA profile was associated with altered gut microbiota composition. In particular, taxa within Bacteroides were reduced in abundance in the feces of these individuals. CONCLUSIONS: Characterization of the portal BA composition in relation to peripheral and fecal BA increased insight into the dynamics of BA metabolism in individuals with obesity. Peripheral BA composition was much more diverse due to microbial metabolism. About 24% of the portal samples was surprisingly low in total BA; the underlying mechanism requires further exploration.

Differences in Psychological Health and Weight Loss after Bariatric Metabolic Surgery between Patients with and without Pain Syndromes.

PURPOSE: Chronic pain and obesity often co-occur, negatively affecting one another and psychological wellbeing. Pain and psychological wellbeing improve after bariatric metabolic surgery (BMS), however, it is unknown whether psychological wellbeing improves differently after weight loss between patients with and without chronic pain. We investigated whether weight loss is associated with greater psychological wellbeing and functioning change after BMS, comparing patients with and without preoperative pain syndromes. METHODS: Depression, health-related quality of life, self-esteem, self-efficacy to exercise and controlling eating behaviours, physical activity, and food cravings were measured before and 24 months after BMS among 276 patients with obesity. The presence of preoperative chronic pain syndromes was examined as a moderator for the relationship between 24-month weight loss and changes in psychological outcomes. RESULTS: Chronic pain syndromes were present among 46% of patients. Weight loss was associated with greater improvement in health-related quality of life, self-efficacy to exercise and controlling eating behaviours, self-esteem and greater amelioration in food cravings. Pain syndromes only moderated negatively the relationship between the postoperative weight loss and change in self-efficacy to control eating behaviours (b = -0.49, CI [-0.88,-0.12]). CONCLUSION: Patients with and without chronic pain showed similar improvements in weight and psychological wellbeing and behaviours after BMS. The relationship between weight loss and the improvement of self-efficacy to control eating behaviours was weaker among patients with chronic pain syndrome. Further work, measuring pain severity over time, is needed to shed light on the mechanism underlying pain and postoperative change in psychological wellbeing and weight loss.

Attachment style and post-bariatric surgery health behaviours: the mediating role of self-esteem and health self-efficacy.

BACKGROUND: Attachment avoidance and anxiety have been linked to overweight and poor health behaviours, yet the mechanisms that underpin the relationship between attachment and health behaviours are not fully understood. Self-esteem and self-efficacy have been found to differ between attachment styles, rendering these variables potential mediators of the relationship. This longitudinal study investigated the serial mediation between preoperative attachment and 2-year post-operative health behaviours through self-esteem and health self-efficacy. METHODS: Participants were 263 bariatric surgery patients (75.7% females, aged 47.7 ± 10.4 years, BMI 38.9 ± 3.6 kg/m2) assessed before the operation and again one and two years after the surgery. Patients completed the Experiences for Close Relationships Brief Scale, Rosenberg Self-esteem scale, Weight Efficacy Lifestyle Questionnaire, Bariatric Surgery Self-Management Questionnaire, Exercise Self-Efficacy Scale and the Exercise Behaviour Scale. RESULTS: Higher preoperative attachment anxiety and avoidance were associated with lower self-esteem one year after bariatric surgery and poorer health self-efficacy two years after the surgery. Self-esteem and health self-efficacy mediated the relationships between preoperative anxious and avoidant attachment and 2- year post-operative diet adherence and physical activity. CONCLUSIONS: Helping patients to feel more worthy and reinforcing their beliefs about their own competences could lead to higher engagement with healthy lifestyle and adherence to treatment protocols, ultimately helping patients to achieve their goals for bariatric surgery. CLINICAL TRIAL REGISTRATION: BARIA: Netherlands Trial Register: NL5837 (NTR5992) https://www.trialregister.nl/trial/5837 . Diabaria: ClinicalTrials.gov identifier (NCT number): NCT03330756.

A Prospective Study on the Diagnoses for Abdominal Pain After Bariatric Surgery: The OPERATE Study.

PURPOSE: Long-term follow-up after bariatric surgery (BS) reveals high numbers of patients with abdominal pain that often remains unexplained. The aim of this prospective study was to give an overview of diagnoses for abdominal pain, percentage of unexplained complaints, number and yield of follow-up visits, and time to establish a diagnosis. MATERIALS AND METHODS: Patients who visited the Spaarne Gasthuis Hospital, The Netherlands, between December 2020 and December 2021 for abdominal pain after BS, were eligible and followed throughout the entire episode of abdominal pain. Distinction was made between presumed and definitive diagnoses. RESULTS: The study comprised 441 patients with abdominal pain; 401 (90.9%) females, 380 (87.7%) had Roux-en-Y gastric bypass, mean (SD) % total weight loss was 31.4 (10.5), and median (IQR) time after BS was 37.0 (11.0-66.0) months. Most patients had 1-5 follow-up visits. Readmissions and reoperations were present in 212 (48.1%) and 164 (37.2%) patients. At the end of the episode, 88 (20.0%) patients had a presumed diagnosis, 183 (41.5%) a definitive diagnosis, and 170 (38.5%) unexplained complaints. Most common definitive diagnoses were cholelithiasis, ulcers, internal herniations, and presumed diagnoses irritable bowel syndrome (IBS), anterior cutaneous nerve entrapment syndrome, and constipation. Median (IQR) time to presumed diagnoses, definitive diagnoses, or unexplained complaints was 16.0 (3.8-44.5), 2.0 (0.0-31.5), and 13.5 (1.0-53.8) days (p < 0.001). Patients with IBS more often had unexplained complaints (OR 95%CI: 4.457 [1.455-13.654], p = 0.009). At the end, 71 patients (16.1%) still experienced abdominal pain. CONCLUSION: Over a third of abdominal complaints after BS remains unexplained. Most common diagnoses were cholelithiasis, ulcers, and internal herniations.

Microbiome-derived ethanol in nonalcoholic fatty liver disease.

To test the hypothesis that the gut microbiota of individuals with nonalcoholic fatty liver disease (NAFLD) produce enough ethanol to be a driving force in the development and progression of this complex disease, we performed one prospective clinical study and one intervention study. Ethanol was measured while fasting and 120 min after a mixed meal test (MMT) in 146 individuals. In a subset of 37 individuals and in an external validation cohort, ethanol was measured in portal vein blood. In an intervention study, ten individuals with NAFLD and ten overweight but otherwise healthy controls were infused with a selective alcohol dehydrogenase (ADH) inhibitor before an MMT. When compared to fasted peripheral blood, median portal vein ethanol concentrations were 187 (interquartile range (IQR), 17-516) times higher and increased with disease progression from 2.1 mM in individuals without steatosis to 8.0 mM in NAFL 21.0 mM in nonalcoholic steatohepatitis. Inhibition of ADH induced a 15-fold (IQR,1.6- to 20-fold) increase in peripheral blood ethanol concentrations in individuals with NAFLD, although this effect was abolished after antibiotic treatment. Specifically, Lactobacillaceae correlated with postprandial peripheral ethanol concentrations (Spearman's rho, 0.42; P < 10-5) in the prospective study. Our data show that the first-pass effect obscures the levels of endogenous ethanol production, suggesting that microbial ethanol could be considered in the pathogenesis of this highly prevalent liver disease.

A systems biology approach to study non-alcoholic fatty liver (NAFL) in women with obesity.

Non-alcoholic fatty liver disease (NAFLD) is now the most frequent global chronic liver disease. Individuals with NAFLD exhibited an increased risk of all-cause mortality driven by extrahepatic cancers and liver and cardiovascular disease. Once the disease is established, women have a higher risk of disease progression and worse outcome. It is therefore critical to deepen the current knowledge on the pathophysiology of NAFLD in women. Here, we used a systems biology approach to investigate the contribution of different organs to this disease. We analyzed transcriptomics profiles of liver and adipose tissues, fecal metagenomes, and plasma metabolomes of 55 women with and without NAFLD. We observed differences in metabolites, expression of human genes, and gut microbial features between the groups and revealed that there is substantial crosstalk between these different omics sets. Multi-omics analysis of individuals with NAFLD may provide novel strategies to study the pathophysiology of NAFLD in humans.

Risk Factors for Symptomatic Gallstone Disease and Gallstone Formation After Bariatric Surgery.

PURPOSE: Patients who undergo bariatric surgery are at risk for developing cholesterol gallstones. We aimed to identify risk factors that are associated with symptomatic gallstone disease and gallstone formation after bariatric surgery. MATERIALS AND METHODS: We included participants of the UPGRADE trial, a multicenter randomized placebo-controlled trial on the prevention of symptomatic gallstone disease with ursodeoxycholic acid (UDCA) after bariatric surgery. The association between patient characteristics and symptomatic gallstone disease, and gallstone formation was evaluated using logistic regression analysis. RESULTS: Of 959 patients, 78 (8%) developed symptomatic gallstone disease within 24 months. Risk factors were the presence of a pain syndrome (OR 2.07; 95% CI 1.03 to 4.17) and asymptomatic gallstones before surgery (OR 3.15; 95% CI 1.87 to 5.33). Advanced age (OR 0.95; 95% CI 0.93 to 0.97) was protective, and UDCA prophylaxis did not reach statistical significance (OR 0.64; 95% CI 0.39 to 1.03). No risk factors were identified for gallstone formation, whereas advanced age (OR 0.98; 95% CI 0.96 to 1.00), statin use (OR 0.42; 95% CI 0.20 to 0.90), and UDCA prophylaxis (OR 0.47; 95% CI 0.30 to 0.73) all reduced the risk. CONCLUSION: Young patients with a preoperative pain syndrome and/or asymptomatic gallstones before bariatric surgery are at increased risk for symptomatic gallstone disease after surgery. Whether statins, either alone or in combination with UDCA prophylaxis, can further reduce the burden of gallstones after bariatric surgery should be investigated prospectively.

Is Adherence to Follow-Up After Bariatric Surgery Necessary? A Systematic Review and Meta-Analysis.

The association of adherence to follow-up (FU) after laparoscopic gastric bypass - and gastric sleeve with weight loss (WL) is unclear. The aim of this study was to evaluate this association. Fourteen full text articles were included in the systematic review. Eight studies were included in the meta-analysis concerning FU up to 3 years postoperatively and 3 for the FU between 3 and 10 years postoperatively. Results showed a significant association between adherence to FU 0.5 to 3 years postoperatively and percentage excess WL (%EWL) but did not demonstrate a significant association between FU > 3 years postoperatively and total WL (%TWL). In conclusion, adherence to FU may not be associated with WL and therefore stringent lifelong FU in its current form should be evaluated.

Ursodeoxycholic acid for the prevention of symptomatic gallstone disease after bariatric surgery (UPGRADE): a multicentre, double-blind, randomised, placebo-controlled superiority trial.

BACKGROUND: Rapid weight loss is a major risk factor for the formation of cholesterol gallstones. Consequently, patients with morbid obesity undergoing bariatric surgery frequently develop symptomatic gallstone disease. This trial assessed the efficacy of ursodeoxycholic acid versus placebo for the prevention of symptomatic gallstone disease after bariatric surgery. METHODS: This multicentre, double-blind, randomised, placebo-controlled superiority trial enrolled patients with an intact gallbladder scheduled for laparoscopic Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy in three hospitals in the Netherlands. Patients were randomly assigned (1:1) by a web-based randomisation module to receive 900 mg ursodeoxycholic acid daily for 6 months or matched placebo. Randomisation was stratified by the presence of asymptomatic gallstones at baseline and type of surgery. Patients, clinicians, and study staff were masked to treatment allocation. The primary endpoint was symptomatic gallstone disease within 24 months, assessed in the modified intention-to-treat population (all randomly assigned eligible patients with any post-randomisation measurement). Prespecified subgroup analyses were done based on the stratification groups. Safety was assessed in all patients who took at least one dose of the study drug. This trial is registered with the Netherlands Trial Register, NL5954. FINDINGS: Between Jan 11, 2017, and Oct 22, 2018, 985 patients were randomly assigned to receive either ursodeoxycholic acid (n=492) or placebo (n=493). 967 patients were included in the modified intention-to-treat population, of whom 959 had data available for primary endpoint assessment. 189 (20%) patients had asymptomatic gallstones at baseline and 78 (8%) received a sleeve gastrectomy. Symptomatic gallstone disease occurred in 31 (6·5%) of 475 patients in the ursodeoxycholic acid group and in 47 (9·7%) of 484 patients in the placebo group (relative risk 0·67, 95% CI 0·43-1·04, p=0·071). Logistic regression showed a significant interaction between ursodeoxycholic acid and the presence of asymptomatic gallstones at baseline (p=0·046), with an effect of ursodeoxycholic acid in patients without (0·47, 0·27-0·84, p=0·0081), and no effect in patients with asymptomatic gallstones at baseline (1·22, 0·61-2·47, p=0·57). The effect was stronger in patients without gallstones at baseline undergoing RYGB (0·37, 0·20-0·71, p=0·0016), whereas the subgroup of patients undergoing sleeve gastrectomy was too small to draw clear conclusions. Adverse events were rare. In the ursodeoxycholic acid group, diarrhoea occurred in four (0·9%) of 444 patients and skin rash in two (0·5%) patients. In the placebo group, diarrhoea occurred in two (0·4%) of 453 patients and skin rash in two (0·4%) patients. The total number of serious adverse events did not significantly differ between the trial groups (75 [17%] in 444 patients in the ursodeoxycholic acid group and 102 [23%] in 453 patients in the placebo group). The most common serious adverse events were abdominal pain and internal hernia. No serious adverse event was attributed to the study drug. INTERPRETATION: Ursodeoxycholic acid prophylaxis did not significantly reduce the occurrence of symptomatic gallstone disease in all patients after bariatric surgery. In patients without gallstones before RYGB surgery, ursodeoxycholic acid treatment reduced the occurrence of symptomatic gallstone disease compared with placebo. Further research is needed to assess the efficacy of ursodeoxycholic acid after sleeve gastrectomy. FUNDING: The Netherlands Organization for Health Research and Development, Zambon Netherlands BV, Foundation for Clinical Research of the Slotervaart Hospital, the Spaarne Gasthuis Academy, and Amsterdam Gastroenterology Endocrinology Metabolism.

Faecal Inflammatory Biomarkers and Gastrointestinal Symptoms after Bariatric Surgery: A Longitudinal Study.

BACKGROUND: Bariatric surgery induces various gastrointestinal (GI) modifications. We performed the first study longitudinally assessing the effect of bariatric surgery on faecal inflammatory biomarker levels and its relation with GI complaints. METHOD: Faecal calprotectin, lactoferrin, and calgranulin-C levels were determined in 41 patients (34 Roux-en-Y [RYGB], 7 sleeves) before and at 6-16 weeks, 6 months, and 1 year after surgery. Changes in biomarker levels and percentage of patients above reference value were determined. Gastrointestinal symptom rating scale (GSRS) was used to assess GI complaints at corresponding time points. The postoperative relation between GSRS score and biomarker levels above reference value was investigated. RESULTS: After RYGB, median calprotectin levels are significantly higher (>188, 104-415 µg/g) than before surgery (40, 19-78 µg/g; p < 0.001), and over 90% of patients have levels above reference value 1 year after surgery. Median lactoferrin was 0.4 (0.2-1.6) µg/g before, and >5.9 (1.8-13.6) µg/g after surgery (p < 0.001). Median calgranulin-C levels remained far below the reference value and were 0.13 (0.05-0.24) µg/g before and <0.23 (0.06-0.33) µg/g after surgery. Similar results were found after sleeve gastrectomy. No difference was seen in GSRS score for patients with calprotectin and lactoferrin levels above reference values. CONCLUSION: Faecal inflammatory biomarkers calprotectin and lactoferrin, but not calgranulin-C, rise above reference values shortly after bariatric surgery and remain elevated in the majority of patients. The discrepancy between calprotectin and calgranulin-C levels suggests no GI inflammation. Furthermore, patients after RYGB with biomarkers above the population reference value do not seem to have more GI complaints.

Weight Loss Results and Compliance with Follow-up after Bariatric Surgery.

PURPOSE: The importance of follow-up (FU) for midterm weight loss (WL) after bariatric surgery is controversial. Compliance to this FU remains challenging. Several risk factors for loss to FU (LtFU) have been mentioned. The aim was therefore to evaluate the association between WL and LtFU 3 to 5 years postoperatively and to identify risk factors for LtFU. MATERIALS AND METHODS: A single-center cross-sectional study in the Netherlands. Between June and October 2018, patients scheduled for a 3-, 4-, or 5-year FU appointment were included into two groups: compliant (to their scheduled appointment and overall maximally 1 missed appointment) and non-compliant (missed the scheduled appointment and at least 1 overall). Baseline, surgical, and FU characteristics were collected and a questionnaire concerning socio-economic factors. RESULTS: In total, 217 patients in the compliant group and 181 in the non-compliant group were included with a median body mass index at baseline of 42.0 and 42.9 respectively. Eighty-eight percent underwent a laparoscopic Roux-en-Y gastric bypass. The median percentage total weight loss for the compliant and non-compliant groups was 30.7% versus 28.9% at 3, 29.3% versus 30.2% at 4, and 29.6% versus 29.9% at 5 years respectively, all p>0.05. Age, persistent comorbidities and vitamin deficiencies, a yearly salary <20,000 euro, no health insurance coverage, and not understanding the importance of FU were risk factors for LtFU. CONCLUSION: Three to 5 years postoperatively, there is no association between LtFU and WL. The compliant group demonstrated more comorbidities and vitamin deficiencies. Younger age, not understanding the importance of FU, and financial challenges were risk factors for LtFU.

Smoking Behaviour and Beliefs About Smoking Cessation After Bariatric Surgery.

PURPOSE: Currently, bariatric surgery is the most effective intervention for treating morbid obesity and its complications. Smoking cessation is likely to improve smoking-related comorbidities and decrease postoperative complications. This study evaluated the smoking behaviour and thoughts about smoking cessation of patients more than 18 months after bariatric surgery. MATERIALS AND METHODS: A cross-sectional study was performed in patients who underwent bariatric surgery from July 2012 to December 2013. A questionnaire was used to evaluate smoking status, thoughts about the health benefits of cessation and characteristics of previous quit attempts in current and former smokers. Finally, actual bariatric surgery outcomes were evaluated in current, former and never smokers. RESULTS: Six hundred nine patients (response rate 52.0%) were included. Of them, 101 (16.6%) patients were current smokers, 239 (39.2%) former smokers and 269 (44.2%) patients were lifetime never smokers. Compared with former smokers, current smokers were less aware of the beneficial effects of smoking cessation on their general health; 66.4% of the former smokers thought smoking cessation would be much better for general health, compared with 20.6% of current smokers. Total weight loss was 2.8% higher in current smokers compared with former smokers. Actual long-term bariatric surgery outcomes were not significantly different between the groups. CONCLUSION: Despite advice to quit smoking and temporary quitting before surgery, a considerable group of bariatric surgery patients continues smoking after surgery. These patients were less aware of the beneficial effects of smoking cessation. This study emphasizes the need for better strategies to increase the number of successful cessations.

Outcome expectation and risk tolerance in patients seeking bariatric surgery.

BACKGROUND: Average long-term outcome after laparoscopic Roux-en-Y gastric bypass is 25% total weight loss. The risk of short-term complications (leakage and bleeding), acute internal herniation, and mortality are 4.0%, 2.5%, and .2%, respectively. There is a paucity of evidence on what patients expect in terms of weight loss and to what extent surgical risks are tolerated. OBJECTIVE: To examine the patient's weight loss expectations and acceptance of the morbidity and mortality risk after primary laparoscopic Roux-en-Y gastric bypass. SETTING: Teaching hospital, Amsterdam, the Netherlands. METHODS: Two-hundred patients participated in a standardized survey after completion of an extensive multidisciplinary screening, before surgery. Weight loss expectations, naive assessment, and acceptation of risks of morbidity and mortality were addressed with standard gamble methods. RESULTS: The 200 participants (156 female, 78%) had a mean age of 45.1 years and a mean body mass index of 42.3 kg/m2. Weight loss was overestimated by 151 patients (75.5%), and 79 participants (39.5%) were disappointed with the predicted weight loss. Median accepted risks on short-term complications, acute internal herniation, and mortality were 35.8% (interquartile range, 21.0%-58.0%), 25.1% (interquartile range, 15.9%-50.8%), and 4.5% (interquartile range, 1.0%-10.0%), respectively. CONCLUSION: Patients seeking bariatric surgery seem to have unrealistic weight loss objectives and are willing to accept substantial risks to achieve these goals.

Autocrine negative feedback regulation of lipolysis through sensing of NEFAs by FFAR4/GPR120 in WAT.

OBJECTIVES: Long-chain fatty acids (LCFAs) released from adipocytes inhibit lipolysis through an unclear mechanism. We hypothesized that the LCFA receptor, FFAR4 (GPR120), which is highly expressed in adipocytes, may be involved in this feedback regulation. METHODS AND RESULTS: Liquid chromatography mass spectrometry (LC-MS) analysis of conditioned media from isoproterenol-stimulated primary cultures of murine and human adipocytes demonstrated that most of the released non-esterified free fatty acids (NEFAs) are known agonists for FFAR4. In agreement with this, conditioned medium from isoproterenol-treated adipocytes stimulated signaling strongly in FFAR4 transfected COS-7 cells as opposed to non-transfected control cells. In transfected 3T3-L1 cells, FFAR4 agonism stimulated Gi- and Go-mini G protein binding more strongly than Gq, effects which were blocked by the selective FFAR4 antagonist AH7614. In primary cultures of murine white adipocytes, the synthetic, selective FFAR4 agonist CpdA inhibited isoproterenol-induced intracellular cAMP accumulation in a manner similar to the antilipolytic control agent nicotinic acid acting through another receptor, HCAR2. In vivo, oral gavage with the synthetic, specific FFAR4 agonist CpdB decreased the level of circulating NEFAs in fasting lean mice to a similar degree as nicotinic acid. In agreement with the identified anti-lipolytic effect of FFAR4, plasma NEFAs and glycerol were increased in FFAR4-deficient mice as compared to littermate controls despite having elevated insulin levels, and cAMP accumulation in primary adipocyte cultures was augmented by treatment with the FFAR4 antagonist conceivably by blocking the stimulatory tone of endogenous NEFAs on FFAR4. CONCLUSIONS: In white adipocytes, FFAR4 functions as an NEFA-activated, autocrine, negative feedback regulator of lipolysis by decreasing cAMP though Gi-mediated signaling.

Upper endoscopy after Roux-en-Y gastric bypass: diagnostic yield and factors associated with relevant findings.

BACKGROUND: After laparoscopic Roux-en-Y gastric bypass many patients present with complaints for which an upper endoscopy is performed. However, often no abnormalities are found. OBJECTIVES: To investigate the incidence of relevant findings at upper endoscopy and identify patient characteristics associated with a relevant finding. SETTING: A high-volume bariatric center. METHODS: A retrospective cohort study was performed. All patients presenting with complaints after laparoscopic Roux-en-Y gastric bypass who consequently underwent a diagnostic upper endoscopy were identified from a prospective endoscopic database. Primary outcomes were the number and type of relevant findings at upper endoscopy and its association with patient characteristics. Relevant findings were defined as abnormalities requiring treatment. RESULTS: Ninety-eight (39.2%) of 250 patients had a relevant finding at upper endoscopy, mostly marginal ulcer and stomal stenosis. Male sex (odds ratio [OR] 3.47 [1.12-10.76]), alcohol consumption (OR 7.27 [1.58-33.36]), dysphagia or suspicion of bleeding as referral reason (OR 3.62 [1.54-8.52] and 39.93 [4.96-321.47], respectively, compared with abdominal pain), an abnormal upper gastrointestinal series (OR 6.81 [2.06-22.48]), and no abdominal ultrasound (OR 7.41 [1.48-37.08] compared with a normal ultrasound) were significantly associated with a relevant finding at upper endoscopy. CONCLUSIONS: In this study sex, alcohol consumption, referral reason, and prior imaging studies were associated with a relevant finding at upper endoscopy after laparoscopic Roux-en-Y gastric bypass.

Self-Reported Smoking Compared to Serum Cotinine in Bariatric Surgery Patients: Smoking Is Underreported Before the Operation.

BACKGROUND: Smoking has been associated with postoperative complications and mortality in bariatric surgery. The evidence for smoking is based on self-report and medical charts, which can lead to misclassification and miscalculation of the associations. Determination of cotinine can objectively define nicotine exposure. We determined the accuracy of self-reported smoking compared to cotinine measurement in three phases of the bariatric surgery trajectory. METHODS: Patients in the phase of screening (screening), on the day of surgery (surgery), and more than 18 months after surgery (follow-up) were consecutively selected. Self-reported smoking was registered and serum cotinine was measured. We evaluated the accuracy of self-reported smoking compared to cotinine, and the level of agreement between self-report and cotinine for each phase. RESULTS: In total, 715 patients were included. In the screening, surgery, and follow-up group, 25.6%, 18.0%, and 15.5%, respectively, was smoking based on cotinine. The sensitivity of self-reported smoking was 72.5%, 31.0%, and 93.5% in the screening, surgery, and follow-up group, respectively (p < 0.001). The specificity of self-report was > 95% in all groups (p < 0.02). The level of agreement between self-report and cotinine was 0.778, 0.414, and 0.855 for the screening, surgery, and follow-up group, respectively. CONCLUSIONS: Underreporting of smoking occurs before bariatric surgery, mainly on the day of surgery. Future studies on effects of smoking and smoking cessation in bariatric surgery should include methods taking into account the issue of underreporting.

Hyperspectral imaging for tissue classification, a way toward smart laparoscopic colorectal surgery.

In the last decades, laparoscopic surgery has become the gold standard in patients with colorectal cancer. To overcome the drawback of reduced tactile feedback, real-time tissue classification could be of great benefit. In this ex vivo study, hyperspectral imaging (HSI) was used to distinguish tumor tissue from healthy surrounding tissue. A sample of fat, healthy colorectal wall, and tumor tissue was collected per patient and imaged using two hyperspectral cameras, covering the wavelength range from 400 to 1700 nm. The data were randomly divided into a training (75%) and test (25%) set. After feature reduction, a quadratic classifier and support vector machine were used to distinguish the three tissue types. Tissue samples of 32 patients were imaged using both hyperspectral cameras. The accuracy to distinguish the three tissue types using both hyperspectral cameras was 0.88 (STD = 0.13) on the test dataset. When the accuracy was determined per patient, a mean accuracy of 0.93 (STD = 0.12) was obtained on the test dataset. This study shows the potential of using HSI in colorectal cancer surgery for fast tissue classification, which could improve clinical outcome. Future research should be focused on imaging entire colon/rectum specimen and the translation of the technique to an intraoperative setting.

Can a laparoscopic Roux-en-Y gastric bypass be safely performed by surgical residents in a bariatric center-of-excellence? The learning curve of surgical residents in bariatric surgery.

BACKGROUND: A learning curve (LC) is a graphic display of the number of consecutive procedures performed necessary to reach competence and is defined by complications and duration of surgery (DOS). There is little evidence on the LC of surgical residents in bariatric surgery. Aim of the study is to evaluate whether the laparoscopic Roux-en-Y gastric bypass (LRYGB) can be safely performed by surgical residents, to evaluate the LC of surgical residents for LRYGB and to assess whether surgical residents fit in the LC of the bariatric center which has been established by their proctors. METHODS: Records of all 3389 consecutive primary LRYGB patients, operated between December 2007 and January 2016 in a bariatric center-of-excellence in Amsterdam, were reviewed. Differences in DOS were assessed by means of a linear regression model. Differences in complications (classified as Clavien-Dindo ≥ 2) were evaluated with the χ 2 or the Fisher exact test. Cases were clustered in groups of 70 for comparison and reported for residents with ≥70 cases as primary surgeon. RESULTS: Four surgeons (S1-4) and three residents (R1-3) performed 2690 (88.2%) and 361 (11.8%) of 3051 LRYGBs, respectively. Median (IQR) DOS was 52.0 (42.0-65.0) min for S1-4 versus 53.0 (46.0-63.0) min for R1-3 (p = 0.52). The LC of R1-3 in their first 70 cases (n = 210) differs significantly from the individual (n = 70) LCs of surgeon 1, 2, and 3, with remarkably shorter DOS for the residents (adjusted p < 0.0001; p < 0.001 and p = 0.0002, respectively) and the same amount of surgical complications 5.1% (137/2690) for S1-4 versus 3.0% (11/361) for R1-3 (p = 0.089). CONCLUSION: Laparoscopic Roux-en-Y gastric bypass can be safely performed by surgical residents under supervision of experienced bariatric surgeons. Surgical residents benefit from the experience of their proctors and they fit faultlessly in the LC of the surgical team, as set out by their proctors in a large bariatric center-of-excellence.