Marginal Ulcer Incidence and the Population of Gastrin Producing G cells Retained in the Gastric Pouch after Roux-en-Y Gastric Bypass: Is There a Relationship?

INTRODUCTION: Marginal ulcers are the most prevalent endoscopic abnormality after RYGB. The etiology is still poorly understood; however, an increase in acid secretion has been strongly implicated as a causal agent. Although gastrin is the greatest stimulant of acid secretion, to date, the presence of gastrin producing G cells retained in the gastric pouch, related to the occurrence of marginal ulcers, has not been evaluated. OBJECTIVE: Evaluate the density of G cells and parietal cells in the gastric pouch of RYGB patients with a diagnosis of marginal ulcer on the post-op EGD. METHOD: We retrospectively evaluated 1104 gastric bypasses performed between 2010 and 2020. Patients with marginal ulcer who met the inclusion criteria and controls were selected from this same population. Endoscopic gastric pouch biopsies were evaluated using immunohistochemical study and HE staining to assess G cell and parietal cell density. RESULTS: In total, 572 (51.8%) of the patients performed endoscopic follow-up after RYGB. The incidence of marginal ulcer was 23/572 (4%), and 3 patients required revision surgery due to a recalcitrant ulcer. The mean time for ulcer identification was 24.3 months (2-62). G cell count per high-power field (× 400) was statistically higher in the ulcer group (p < 0.05). There was no statistical difference in parietal cell density between groups (p 0.251). CONCLUSION: Patients with a marginal ulcer after gastric bypass present a higher density of gastrin-producing G cells retained in the gastric pouch.

Accuracy of ultrasound diagnosis of nonalcoholic fatty liver disease in patients with classes II and III obesity: A pathological image study.

Liver biopsy is the gold standard method to diagnose nonalcoholic fatty liver disease (NAFLD). However, ultrasound is widely recommended as the first-line imaging test for individuals with suspected NAFLD. This study aimed to estimate the accuracy of ultrasound as a screening test for NAFLD compared to liver biopsy in a cohort of patients with class II and III obesity undergoing bariatric surgery. This retrospective study included patients undergoing Roux-en-Y gastric bypass in southern Brazil between 2010 and 2019 who were screened for NAFLD with both ultrasound and liver biopsy. All samples were collected by a core biopsy needle and were analyzed by the same pathologist. Sensitivity, specificity, and positive and negative predictive values of ultrasound were estimated. The final database included 227 patients, mostly female (84%) and white (83.6%), with a mean age of 42.5 ± 10.2 years and a mean preoperative body mass index of 49.5 ± 8.4 kg/m2. A total of 153 subjects (67.4%) were diagnosed with NAFLD through liver biopsies: 41 (18%) had fatty liver and 112 (49.3%) had nonalcoholic steatohepatitis. Ultrasound sensitivity was 88.9% and specificity was 44.6%. Positive and negative predictive values were 76.8% and 66.0%, respectively. Positive likelihood ratio was 1.6 (95% CI 1.30-1.98), and negative likelihood ratio was 0.25 (95% CI 0.15-0.42). Therefore, approximately three every four subjects with an ultrasound suggesting NAFLD were true positives. Ultrasound showed a good sensitivity in detecting NAFLD in patients with class II and III obesity.

-866G/A and Ins/Del polymorphisms in UCP2 gene are associated with reduced short-term weight loss in patients who underwent Roux-en-Y gastric bypass.

BACKGROUND: Uncoupling protein 2 (UCP2) plays an important role in energy expenditure regulation. Previous studies have associated the common -866G/A (rs659366) and Ins/Del polymorphisms in the UCP2 gene with metabolic and obesity-related phenotypes. However, it is still unclear whether these polymorphisms influence weight loss after bariatric surgery. OBJECTIVES: To investigate whether UCP2 -866G/A and Ins/Del polymorphisms are associated with weight loss outcomes after bariatric surgery. SETTING: Longitudinal study in a university hospital. METHODS: We retrospectively evaluated 186 patients who underwent Roux-en-Y gastric bypass (RYGB) surgery for clinical and laboratory characteristics in the preoperative period, 6, 12, and 18 months after RYGB. The -866G/A (rs659366) polymorphism was genotyped using real-time PCR, while the Ins/Del polymorphism was genotyped by direct separation of PCR products in 2.5% agarose gels. RESULTS: Patients with the -866A/A genotype showed higher body mass index (BMI) after 6, 12, and 18 months of surgery and excess body weight after 6 and 12 months compared with G/G patients. They also showed lower excess weight loss (EWL%) after 6 and 12 months of surgery. Ins allele carriers (Ins/Ins + Ins/Del) had lower delta (Δ) BMI 12 months after surgery compared with Del/Del patients. Accordingly, patients carrying haplotypes with ≥2 risk alleles of these polymorphisms had higher BMI and excess weight and lower EWL% during follow-up. CONCLUSION: UCP2 -866A/A genotype is associated with higher BMI and excess weight and lower EWL% during an 18-month follow-up of patients who underwent RYGB, while the Ins allele seems to be associated with lower ΔBMI 12 months after surgery. Further studies are needed to confirm the associations of the -866G/A and Ins/Del polymorphisms with weight loss after bariatric surgery.

UCP2, IL18, and miR-133a-3p are dysregulated in subcutaneous adipose tissue of patients with obesity.

The aim of this study was to compare the expression of UCP2, NLRP3, IL1B, IL18, and miR-133a-3p in subcutaneous adipose tissue (SAT) of 61 patients divided according to BMI: Group 1 (n = 8; BMI<25.0 kg/m2), Group 2 (n = 24; BMI 30.0-39.9 kg/m2), and Group 3 (n = 29; BMI≥40.0 kg/m2). SAT biopsies were obtained from individuals who underwent bariatric surgery or elective abdominal surgery. Gene expressions were quantified using qPCR. Bioinformatics analyses were employed to investigate target genes and pathways related to miR-133a-3p. UCP2 and miR-133a-3p expressions were decreased in SAT of Groups 2 and 3 while IL18 was increased compared to Group 1. NLRP3 and IL1B expressions did not differ between groups; however, NLRP3 was positively correlated with waist circumference and excess weight. Bioinformatics analysis demonstrated that UCP2 and NLRP3 are targets of miR-133a-3p. In conclusion, UCP2 and miR-133a-3p expressions are downregulated in patients with obesity, while IL18 is upregulated. NRLP3 is correlated with waist circumference and weight excess.

Improvement of exercise capacity and peripheral metaboreflex after bariatric surgery.

BACKGROUND: Bariatric surgery is the only predictable method to obtain weight loss in severe obesity. Poor physical performance of obese individuals may be mediated by the peripheral metaboreflex, which controls blood flow redistribution to exercising muscles. Weight reduction improves exercise capacity through several possible mechanisms that are insufficiently understood. We hypothesized that the metaboreflex is one among the causes of improvement in exercise capacity after weight loss. This study thus aimed to examine the effect of bariatric surgery on exercise performance and metaboreflex. METHODS: Severely obese patients were assessed before and 3 months after bariatric surgery. Metaboreflex was evaluated by the technique of selective induction by post-exercise circulatory occlusion (PECO+) after isometric handgrip exercise at 30% of maximum voluntary contraction. The exercise capacity was assessed by 6-min walking test. RESULTS: Seventeen patients completed the protocol. Body mass index decreased from 46.4 ± 2 to 36.6 ± 2 kg/m2 (P < 0.001). The distance walked in 6 min increased from 489 ± 14 to 536 ± 14 m (P < 0.001). The peripheral metaboreflex activity, expressed by the area under the curve of vascular resistance, was lower after than before bariatric surgery (42 ± 5 to 20 ± 4 units, P = 0.003). Heart rate, blood pressure, and vascular resistance were also significantly decreased. The correlation between change in distance walked in 6 min and change in peripheral metaboreflex activity was not significant. CONCLUSIONS: Weight loss after bariatric surgery increases exercise capacity and reduces peripheral metaboreflex, heart rate, and blood pressure. Further investigation on the role of metaboreflex regarding mechanisms of exercise capacity of individuals with obesity is warranted.