ß-cell pancreatic dysfunction plays a role in hyperglycemic peaks observed after gastric bypass surgery of obese patients

Use of Continuous Glucose Monitoring in Patients Following Bariatric Surgery: A Scoping Review

The objective of this scoping review was to summarize the emerging literature on the use of continuous glucose monitoring (CGM) in post-bariatric surgery patients, with a focus on its features (e.g., device, mode, and accuracy), as well as purposes and outcomes of utilization. Three databases (PubMed, EMBASE, and Web of Science) were searched to obtain relevant studies. Results suggested that most studies used CGM for 3-7 days under blinded mode. Accuracy data were available in only one study, which reported a mean absolute relative difference of 21.7% for Freestyle Libre. The primary applications of CGM were for elucidating glucose patterns and assessing glycemic treatment outcomes. No study has tested the effect of CGM as an intervention strategy to enhance glucose control.

Sleeve Gastrectomy-Induced Weight Loss Increases Insulin Clearance in Obese Mice

Sleeve gastrectomy (SG) successfully recovers metabolic homeostasis in obese humans and rodents while also resulting in the normalization of insulin sensitivity and insulinemia. Reduced insulin levels have been attributed to lower insulin secretion and increased insulin clearance in individuals submitted to SG. Insulin degradation mainly occurs in the liver in a process controlled, at least in part, by the insulin-degrading enzyme (IDE). However, research has yet to explore whether liver IDE expression or activity is altered after SG surgery. In this study, C57BL/6 mice were fed a chow (CTL) or high-fat diet (HFD) for 10 weeks. Afterward, the HFD mice were randomly assigned to two groups: sham-surgical (HFD-SHAM) and SG-surgical (HFD-SG). Here, we confirmed that SG improves glucose-insulin homeostasis in obese mice. Additionally, SG reduced insulinemia by reducing insulin secretion, assessed by the analysis of plasmatic C-peptide content, and increasing insulin clearance, which was evaluated through the calculation of the plasmatic C-peptide:insulin ratio. Although no changes in hepatic IDE activity were observed, IDE expression was higher in the liver of HFD-SG compared with HFD-SHAM mice. These results indicate that SG may be helpful to counteract obesity-induced hyperinsulinemia by increasing insulin clearance, likely through enhanced liver IDE expression.

The Effects of Bariatric Surgery on Islet Function, Insulin Secretion, and Glucose Control

Although bariatric surgery was developed primarily to treat morbid obesity, evidence from the earliest clinical observations to the most recent clinical trials consistently demonstrates that these procedures have substantial effects on glucose metabolism. A large base of research indicates that bariatric surgeries such as Roux-en-Y gastric bypass (RYGB), vertical sleeve gastrectomy (VSG), and biliopancreatic diversion (BPD) improve diabetes in most patients, with effects frequently evident prior to substantial weight reduction. There is now unequivocal evidence from randomized controlled trials that the efficacy of surgery is superior to intensive life-style/medical management. Despite advances in the clinical understanding and application of bariatric surgery, there remains only limited knowledge of the mechanisms by which these procedures confer such large changes to metabolic physiology. The improvement of insulin sensitivity that occurs with weight loss (e.g., the result of diet, illness, physical training) also accompanies bariatric surgery. However, there is evidence to support specific effects of surgery on insulin clearance, hepatic glucose production, and islet function. Understanding the mechanisms by which surgery affects these parameters of glucose regulation has the potential to identify new targets for therapeutic discovery. Studies to distinguish among bariatric surgeries on key parameters of glucose metabolism are limited but would be of considerable value to assist clinicians in selecting specific procedures and investigators in delineating the resulting physiology. This review is based on literature related to factors governing glucose metabolism and insulin secretion after the commonly used RYGB and VSG, and the less frequently used BPD and adjustable gastric banding.

Herbal Medicine for Dumping Syndrome: A Systematic Review and Meta-Analysis

Background: Dumping syndrome is a common complication of surgical treatment of gastric cancer, but conventional therapy has limitations related to symptom care due to its structural cause and the decreased quality of life. Objectives: The objective of this review was to assess the clinical evidence for the effectiveness of herbal medicine as a treatment for dumping syndrome. Methods: A literature review was conducted using 16 databases from their inceptions to March 2018. All randomized controlled trials (RCTs) of herbal medicine used to treat dumping syndrome patients were included and meta-analyzed. Methodological quality was assessed using the Cochrane Handbook for Systematic Reviews of Interventions. Results: A total of 174 dumping syndrome patients of 3 trials met all inclusion criteria. Two trials assessed the effectiveness of herbal medicine on the symptom response rate compared with conventional pharmacotherapy. Their results suggested significant effects in favor of herbal medicine (risk ratio [RR] = 1.37, 95% confidence interval [CI] = 1.16-1.63, P = .0003, heterogeneity τ² = 0, χ² = 0.02, P = .88, I² = 0%). One trial assessed its effectiveness on the improvement rate of overall symptoms compared with conventional conservative complex therapy, such as postural management, diet regulation, and counseling (RR = 1.23, 95% CI = 0.96-1.58). Conclusions: Due to the small sample size, scarcity of reported articles, and lack of quality of the current RCTs, it was concluded that the effectiveness of herbal medicine in treating dumping syndrome is unclear.

Glucose Profiles in Pregnant Women After a Gastric Bypass : Findings from Continuous Glucose Monitoring

BACKGROUND

The diagnosis of gestational diabetes mellitus (GDM) usually requires an oral glucose tolerance test, but this procedure seems inappropriate after gastric bypass surgery (Roux-en-Y gastric bypass (RYGB)) due to specific altered glycemic responses. We aimed here at describing continuous glucose monitoring (CGM) profile of pregnant women after RYGB.

METHODS

CGM was performed in 35 consecutive pregnant women after RYGB at 26.2 ± 5 weeks of gestation.

RESULTS

After RYGB, pregnant women display high postprandial interstitial glucose (IG) peaks and low IG before and 2 h after meals. The postprandial IG peak is reached early, within 54 ± 9 min. The maximum IG values reach 205 mg/dl, and the percentage of time above 140 mg/dl (6.6 ± 7 %) is similar to what is described in GDM women.

CONCLUSIONS

This study is the first to describe CGM profile in pregnant women after RYGB. CGM features are similar to those of non-pregnant post-RYGB patients, characterized by wide and rapid changes in postprandial IG, and high exposure to hyperglycemia. The exposure to hyperglycemia is similar to what is reported in GDM although the time to postprandial peak is shorter. CGM could be an additional useful approach to screen for glucose intolerance during pregnancy after RYGB.