How do patients' clinical phenotype and the physiological mechanisms of the operations impact the choice of bariatric procedure?

Bariatric surgery is currently the most effective option for the treatment of morbid obesity and its associated comorbidities. Recent clinical and experimental findings have challenged the role of mechanical restriction and caloric malabsorption as the main mechanisms for weight loss and health benefits. Instead, other mechanisms including increased levels of satiety gut hormones, altered gut microbiota, changes in bile acid metabolism, and/or energy expenditure have been proposed as explanations for benefits of bariatric surgery. Beside the standard proximal Roux-en-Y gastric bypass and the biliopancreatic diversion with or without duodenal switch, where parts of the small intestine are excluded from contact with nutrients, resectional techniques like the sleeve gastrectomy (SG) have recently been added to the armory of bariatric surgeons. The variation of weight loss and glycemic control is vast between but also within different bariatric operations. We surveyed members of the Swiss Society for the Study of Morbid Obesity and Metabolic Disorders to assess the extent to which the phenotype of patients influences the choice of bariatric procedure. Swiss bariatric surgeons preferred Roux-en-Y gastric bypass and SG for patients with type 2 diabetes mellitus and patients with a body mass index >50 kg/m(2), which is consistent with the literature. An SG was preferred in patients with a high anesthetic risk or previous laparotomy. The surgeons' own experience was a major determinant as there is little evidence in the literature for this approach. Although trends will come and go, evidence-based medicine requires a rigorous examination of the proof to inform clinical practice

Innate sensing of chitin and chitosan

Chitin is the second most common polysaccharide found in nature. It is present in crustacean shells, insect exoskeletons, parasitic nematode eggs and gut linings, and in the cell wall of fungi. The deacetylated derivative of chitin, chitosan, is less common but is particularly evident in certain species of fungi, such as Cryptococcus, and the cyst wall of Entamoeba. How mammals sense and respond to these polymers is not well understood, and conflicting reports on their immunological activity have led to some controversy. Despite this, promising translational applications that exploit the unique properties of chitin and chitosan are being developed

Chirurgie als pluripotentes Instrument gegen eine metabolische Erkrankung: Was sind die Mechanismen?

Zusammenfassung: Die bariatrische/metabolische Chirurgie stellt derzeit die effektivste Therapie zur dauerhaften Gewichtsreduktion und Verbesserung der mit Adipositas assoziierten metabolischen Begleiterkrankungen wie Diabetes mellitus Typ 2, arterielle Hypertonie, Lipidstoffwechselstörungen und kardiovaskuläre Erkrankungen dar. Trotz kontinuierlich steigender Operationszahlen in Deutschland und weltweit sowie belegter Effektivität sind die genauen Wirkmechanismen der Operationsverfahren jedoch nicht vollständig geklärt. Einer der am häufigsten durchgeführten und am besten untersuchten Eingriffe ist der Roux-en-Y-Magenbypass (RYGB), dessen Wirksamkeit traditionell durch mechanische Nahrungsrestriktion und kalorische Malabsorption begründet wurde. Inzwischen hat sich allerdings gezeigt, dass die zugrunde liegenden Mechanismen weitaus komplexer sind und dass physiologische Prozesse wie beispielsweise veränderte Spiegel verschiedener gastrointestinaler Hormone, ein gesteigerter Energieumsatz und eine modifizierte Zusammensetzung des intestinalen Mikrobioms eine wichtigere Rolle spielen. Nachdem die Verbesserung der metabolischen Begleiterkrankungen lange Zeit als Folgeeffekt der Gewichtsreduktion nach RYGB interpretiert wurde, hat sich inzwischen gezeigt, dass dies zumindest teilweise gewichtsunabhängig zu sein scheint und direkt durch physiologische Veränderungen vermittelt wird. Dieser Artikel soll eine Übersicht zu den potenziellen und aktuell wichtigsten Wirkmechanismen der RYGB-Operation liefern, die sowohl an der Therapie des Übergewichts als auch der adipositasassoziierten metabolischen Begleiterkrankungen beteiligt sind

Chirurgie als pluripotentes Instrument gegen eine metabolische Erkrankung

Die bariatrische/metabolische Chirurgie stellt derzeit die effektivste Therapie zur dauerhaften Gewichtsreduktion und Verbesserung der mit Adipositas assoziierten metabolischen Begleiterkrankungen wie Diabetes mellitus Typ 2, arterielle Hypertonie, Lipidstoffwechselstörungen und kardiovaskuläre Erkrankungen dar. Trotz kontinuierlich steigender Operationszahlen in Deutschland und weltweit sowie belegter Effektivität sind die genauen Wirkmechanismen der Operationsverfahren jedoch nicht vollständig geklärt. Einer der am häufigsten durchgeführten und am besten untersuchten Eingriffe ist der Roux-en-Y-Magenbypass (RYGB), dessen Wirksamkeit traditionell durch mechanische Nahrungsrestriktion und kalorische Malabsorption begründet wurde. Inzwischen hat sich allerdings gezeigt, dass die zugrunde liegenden Mechanismen weitaus komplexer sind und dass physiologische Prozesse wie beispielsweise veränderte Spiegel verschiedener gastrointestinaler Hormone, ein gesteigerter Energieumsatz und eine modifizierte Zusammensetzung des intestinalen Mikrobioms eine wichtigere Rolle spielen. Nachdem die Verbesserung der metabolischen Begleiterkrankungen lange Zeit als Folgeeffekt der Gewichtsreduktion nach RYGB interpretiert wurde, hat sich inzwischen gezeigt, dass dies zumindest teilweise gewichtsunabhängig zu sein scheint und direkt durch physiologische Veränderungen vermittelt wird. Dieser Artikel soll eine Übersicht zu den potenziellen und aktuell wichtigsten Wirkmechanismen der RYGB-Operation liefern, die sowohl an der Therapie des Übergewichts als auch der adipositasassoziierten metabolischen Begleiterkrankungen beteiligt sind

Computed tomography for evaluation of abdominal wall hernias-what is the value of the Valsalva maneuver?

PURPOSE To investigate the differences in the visibility and size of abdominal wall hernias in computed tomography (CT) with and without Valsalva maneuver. METHODS This single-center retrospective study included consecutive patients who underwent abdominal CTs with Valsalva maneuver between January 2018 and January 2022. Inclusion criteria was availability of an additional non-Valsalva CT within 6 months. A combined reference standard including clinical and surgical findings was used. Two independent, blinded radiologists measured the hernia sac size and rated hernia visibility on CTs with and without Valsalva. Differences were tested with a Wilcoxon signed rank test and McNemar's test. RESULTS The final population included 95 patients (16 women; mean age 46 ± 11.6 years) with 205 hernias. Median hernia sac size on Valsalva CT was 31 mm compared with 24 mm on non-Valsalva CT (p < 0.001). In 73 and 82% of cases, the hernias were better visible on CT with Valsalva as compared to that without. 14 and 17% of hernias were only visible on the Valsalva CT. Hernia visibility on non-Valsalva CT varied according to subtype, with only 0 and 3% of umbilical hernias not being visible compared with 43% of femoral hernias. CONCLUSIONS Abdominal wall hernias are larger and better visible on Valsalva CT compared with non-Valsalva CT in a significant proportion of patients and some hernias are only visible on the Valsalva CT. Therefore, this method should be preferred for the evaluation of abdominal wall hernias

Effect of inulin on breath hydrogen, postprandial glycemia, gut hormone release, and appetite perception in RYGB patients: a prospective, randomized, cross-over pilot study

BACKGROUND AND OBJECTIVE Large intestinal fermentation of dietary fiber may control meal-related glycemia and appetite via the production of short-chain fatty acids (SCFA) and the secretion of glucagon-like peptide-1 (GLP-1) and peptide YY (PYY). We investigated whether this mechanism contributes to the efficacy of the Roux-en-Y gastric bypass (RYGB) by assessing the effect of oligofructose-enriched inulin (inulin) vs. maltodextrin (MDX) on breath hydrogen (a marker of intestinal fermentation), plasma SCFAs, gut hormones, insulin and blood glucose concentrations as well as appetite in RYGB patients. METHOD Eight RYGB patients were studied on two occasions before and ~8 months after surgery using a cross-over design. Each patient received 300 ml orange juice containing 25 g inulin or an equicaloric load of 15.5 g MDX after an overnight fast followed by a fixed portion snack served 3 h postprandially. Blood samples were collected over 5 h and breath hydrogen measured as well as appetite assessed using visual analog scales. RESULTS Surgery increased postprandial secretion of GLP-1 and PYY (P ≤ 0.05); lowered blood glucose and plasma insulin increments (P ≤ 0.05) and reduced appetite ratings in response to both inulin and MDX. The effect of inulin on breath hydrogen was accelerated after surgery with an increase that was earlier in onset (2.5 h vs. 3 h, P ≤ 0.05), but less pronounced in magnitude. There was, however, no effect of inulin on plasma SCFAs or plasma GLP-1 and PYY after the snack at 3 h, neither before nor after surgery. Interestingly, inulin appeared to further potentiate the early-phase glucose-lowering and second-meal (3-5 h) appetite-suppressive effect of surgery with the latter showing a strong correlation with early-phase breath hydrogen concentrations. CONCLUSION RYGB surgery accelerates large intestinal fermentation of inulin, however, without measurable effects on plasma SCFAs or plasma GLP-1 and PYY. The glucose-lowering and appetite-suppressive effects of surgery appear to be potentiated with inulin

Diagnostic performance of CT with Valsalva maneuver for the diagnosis and characterization of inguinal hernias

PURPOSE Inguinal hernias are mainly diagnosed clinically, but imaging can aid in equivocal cases or for treatment planning. The purpose of this study was to evaluate the diagnostic performance of CT with Valsalva maneuver for the diagnosis and characterization of inguinal hernias. METHODS This single-center retrospective study reviewed all consecutive Valsalva-CT studies between 2018 and 2019. A composite clinical reference standard including surgery was used. Three blinded, independent readers (readers 1-3) reviewed the CT images and scored the presence and type of inguinal hernia. A fourth reader measured hernia size. Interreader agreement was quantified with Krippendorff's α coefficients. Sensitivity, specificity, and accuracy of Valsalva-CT for the detection of inguinal hernias was computed for each reader. RESULTS The final study population included 351 patients (99 women) with median age 52.2 years (interquartile range (IQR), 47.2, 68.9). A total of 381 inguinal hernias were present in 221 patients. Sensitivity, specificity, and accuracy were 85.8%, 98.1%, and 91.5% for reader 1, 72.7%, 92.5%, and 81.8% for reader 2, and 68.2%, 96.3%, and 81.1% for reader 3. Hernia neck size was significantly larger in cases correctly detected by all three readers (19.0 mm, IQR 13, 25), compared to those missed by all readers (7.0 mm, IQR, 5, 9; p < 0.001). Interreader agreement was substantial (α = 0.723) for the diagnosis of hernia and moderate (α = 0.522) for the type of hernia. CONCLUSION Valsalva-CT shows very high specificity and high accuracy for the diagnosis of inguinal hernia. Sensitivity is only moderate which is associated with missed smaller hernias

Microstructural Changes in Human Ingestive Behavior After Roux-en-Y Gastric Bypass During Liquid Meals

BACKGROUND. Roux-en-Y gastric bypass (RYGB) decreases energy intake and is, therefore, an effective treatment of obesity. The behavioral bases of the decreased calorie intake remain to be elucidated. We applied the methodology of microstructural analysis of meal intake to establish the behavioral features of ingestion in an effort to discern the various controls of feeding as a function of RYGB. METHODS. The ingestive microstructure of a standardized liquid meal in a cohort of 11 RYGB patients, in 10 patients with obesity, and in 10 healthy-weight adults was prospectively assessed from baseline to 1 year with a custom-designed drinkometer. Statistics were performed on log-transformed ratios of change from baseline so that each participant served as their own control, and proportional increases and decreases were numerically symmetrical. Data-driven (3 seconds) and additional burst pause criteria (1 and 5 seconds) were used. RESULTS. At baseline, the mean meal size (909.2 versus 557.6 kCal), burst size (28.8 versus 17.6 mL), and meal duration (433 versus 381 seconds) differed between RYGB patients and healthy-weight controls, whereas suck volume (5.2 versus 4.6 mL) and number of bursts (19.7 versus 20.1) were comparable. At 1 year, the ingestive differences between the RYGB and healthy-weight groups disappeared due to significantly decreased burst size (P = 0.008) and meal duration (P = 0.034) after RYGB. The first-minute intake also decreased after RYGB (P = 0.022). CONCLUSION. RYGB induced dynamic changes in ingestive behavior over the first postoperative year. While the eating pattern of controls remained stable, RYGB patients reduced their meal size by decreasing burst size and meal duration, suggesting that increased postingestive sensibility may mediate postbariatric ingestive behavior. TRIAL REGISTRATION. NCT03747445; https://clinicaltrials.gov/ct2/show/NCT03747445. FUNDING. This work was supported by the University of Zurich, the Swiss National Fund (32003B_182309), and the Olga Mayenfisch Foundation. Bálint File was supported by the Hungarian Brain Research Program Grant (grant no. 2017-1.2.1-NKP-2017-00002)