Response to glucose tolerance testing and solid high carbohydrate challenge: comparison between Roux-en-Y gastric bypass, vertical sleeve gastrectomy, and duodenal switch

Nutritional load in post-prandial oxidative stress and the pathogeneses of diabetes mellitus

Diabetes mellitus affected more than 500 million of people globally, with an annual mortality of 1.5 million directly attributable to diabetic complications. Oxidative stress, in particularly in post-prandial state, plays a vital role in the pathogenesis of the diabetic complications. However, oxidative status marker is generally poorly characterized and their mechanisms of action are not well understood. In this work, we proposed a new framework for deep characterization of oxidative stress in erythrocytes (and in urine) using home-built micro-scale NMR system. The dynamic of post-prandial oxidative status (against a wide variety of nutritional load) in individual was assessed based on the proposed oxidative status of the red blood cells, with respect to the traditional risk-factors such as urinary isoprostane, reveals new insights into our understanding of diabetes. This new method can be potentially important in drafting guidelines for sub-stratification of diabetes mellitus for clinical care and management.

Hyperinsulinemic Hypoglycemia after Bariatric Surgery

Postprandial hyperinsulinemic hypoglycemia (PHH) is one of the serious complications after bariatric surgery, it can lead life-threatening neuroglycopenic symptoms, such as seizures, disorientation, impairment of version and loss of consciousness without any premonitory. The presentation, prevalence, diagnosis, pathology and treatment are reviewed in this summary.

Clinical Practice Guidelines for Childbearing Female Candidates for Bariatric Surgery, Pregnancy, and Post-partum Management After Bariatric Surgery

Emerging evidence suggests that bariatric surgery improves pregnancy outcomes of women with obesity by reducing the rates of gestational diabetes, pregnancy-induced hypertension, and macrosomia. However, it is associated with an increased risk of a small-for-gestational-age fetus and prematurity. Based on the work of a multidisciplinary task force, we propose clinical practice recommendations for pregnancy management following bariatric surgery. They are derived from a comprehensive review of the literature, existing guidelines, and expert opinion covering the preferred type of surgery for women of childbearing age, timing between surgery and pregnancy, contraception, systematic nutritional support and management of nutritional deficiencies, screening and management of gestational diabetes, weight gain during pregnancy, gastric banding management, surgical emergencies, obstetrical management, and specific care in the postpartum period and for newborns.

Evaluation of postprandial hypoglycemia in patients with nonalcoholic fatty liver disease by oral glucose tolerance testing and continuous glucose monitoring

OBJECTIVE

Nonalcoholic fatty liver disease (NAFLD) is often associated with insulin resistance and glucose intolerance. Postprandial hypoglycemia frequently occurs in NAFLD patients; however, the details remain unclear.

PATIENTS AND METHODS

The 75-g oral glucose tolerance test (75gOGTT) in 502 patients with biopsy-proven NAFLD and continuous glucose monitoring (CGM) in 20 patients were performed, and the characteristics and causes of postprandial hypoglycemia were investigated.

RESULTS

The proportion of patients in the Hypo subgroup [plasma glucose (PG) at 180 min<fasting-PG (FPG)] among patients with normal glucose tolerance was significantly higher than that with diabetes mellitus and impaired glucose tolerance or impaired fasting glucose. FPG and hemoglobin A1c (HbA1c) were lower, and area under the curve of total insulin secretion within 120 min (<120 min) was higher in Hypo than Hyper in overall patients. Although FPG and PG at 30 min were higher in Hypo than Hyper, HOMA-IR and the insulinogenic index were not different in normal glucose tolerance and impaired glucose tolerance or impaired fasting glucose. In multivariate logistic regression analysis, low HbA1c, low fasting immunoreactive insulin, and high area under the curve of total insulin secretion (<120 min) were found to be independent factors associated with hypoglycemia. CGM showed postprandial hypoglycemia until lunch in 70% of NAFLD patients. However, no remarkable relationship in terms of hypoglycemia was identified between the 75gOGTT and CGM.

CONCLUSION

Postprandial hypoglycemia was identified in many NAFLD patients detected by 75gOGTT and CGM. It was clarified that important causes of postprandial hypoglycemia were related to low HbA1c, an early elevation of PG, low fasting and relatively low early insulin secretion, and delayed hyperinsulinemia.

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.

Is testing for postprandial hyperinsulinemic hypoglycemia after gastric bypass necessary?

INTRODUCTION

Postprandial hyperinsulinemic hypoglycemia (pHH) is an increasingly reported complication after Roux-en-Y gastric bypass (RYGB). As pHH can cause life-threatening emergencies if occurring without warning symptoms, challenge testing may detect patients at risk. The study objective was to determine the frequency of occurrence of pHH with or without symptoms of hypoglycemia after RYGB.

METHODS

We undertook an observational cohort study of consecutive, unselected patients approximately one year after uncomplicated RYGB. To simulate normal habits, all patients received a standardized carbohydrate-rich solid mixed meal. Plasma glucose and insulin were measured at 30, 60, 90, 120, and 150 min thereafter. Symptoms were classified as autonomous or neuroglycopenic. Patients with hypoglycemia (plasma glucose <3.0 mmol/L [55 mg/dL]), were tested a second time with a protein-rich solid mixed meal.

RESULTS

113 patients were included. Total weight loss at the first follow-up check (14 ± 0.4 months) was 33.97 ± 9.3%. After the carbohydrate-rich meal, glucose dropped to <3.0 mmol/L in 13.2% (n = 15) of patients vs no drop to <3.0 mmol/L after a protein-rich meal. The pHH occurred in 11.5% (n = 13) of patients. Asymptomatic patients (5.3%, n = 6) carried an increased risk (p = 0.008) for pHH. One patient needed emergency treatment after sudden loss of consciousness after the carbohydrate-rich meal.

CONCLUSIONS

The occurrence of pHH was quite high in our study population with 11.5% thereof 5.3% asymptomatic. We therefore suggest that detection of these patients warrants a screening of patients after RYGB. At-risk patients should than be adequately advised to avoid carbohydrate-rich meals in order to optimize risk management.

Insulinoma After Bariatric Surgery: Diagnostic Dilemma and Therapeutic Approaches

Hypoglycemia is increasingly recognized as a complication of bariatric surgery. Typically, hypoglycemia does not appear immediately postoperatively, but rather more than 1 year later, and usually occurs 1-3 h after meals. While rare, insulinoma has been reported after bariatric surgery. Clinical factors which should raise suspicion for insulinoma and the need for comprehensive clinical and biochemical evaluation include hypoglycemia occurring in the fasting state, predating bariatric surgery, and/or worsening immediately postoperatively, and lack of response to conservative therapy. Localization and successful resection of insulinoma can be achieved using novel endoscopic ultrasound and surgical approaches. In summary, hypoglycemia presenting shortly after gastric bypass or with a dominant fasting pattern should be fully evaluated to exclude insulinoma. Additionally, evaluation prior to gastric bypass should include screening for history of hypoglycemia symptoms.

Bariatric surgery in managing diabetes mellitus

PURPOSE OF REVIEW

Obesity is a worldwide epidemic, having profound effects on Western populations. Bariatric surgery has long been employed to treat obesity and its related comorbidities. Over time, researchers have amassed significant data to support bariatric surgery in the pursuit of treating diabetes mellitus. This review serves to introduce the most recent findings and their relation to the various bariatric surgical options as bariatric surgery will continue to cement itself in the treatment paradigm of diabetes mellitus.

RECENT FINDINGS

Numerous studies performed in the past 10 years have demonstrated the improvement or cessation of diabetes with bariatric surgical intervention. In comparing the vertical sleeve gastrectomy and Roux-en-Y gastric bypass, data demonstrate a more beneficial response of diabetes to the Roux-en-Y gastric bypass, and an even further exaggerated response with the biliopancreatic diversion/duodenal switch. The benefit has long been established, but what causes the improvement in diabetes mellitus after bariatric surgery? Recent data suggest a decrease in circulating bile salts as well as changes to inflammatory markers and circulating cytokines. Furthermore, tailoring of existing surgical procedures has led to the development of the SIPS procedure, and its benefit is demonstrated in bypassing a large portion of intestine while eliminating an enteroenterostomy, helping to reduce short gut syndrome and resultant diarrhea.

SUMMARY

The surgical climate within the bariatric field is changing and will continue to do so in the future. As the understanding of the causes or mechanisms in which bariatric surgery improves metabolic disorders becomes more evident, the process of individualizing care for specific patients will become more prevalent.

Risk Factors for Spontaneously Self-Reported Postprandial Hypoglycemia After Bariatric Surgery

CONTEXT

Postprandial hypoglycemia (PPHG) is a recognized complication of Roux-en-Y gastric bypass (RYGB) surgery. Data on PPHG after laparoscopic sleeve gastrectomy (LSG) are scant.

OBJECTIVE

The objective of the study was to identify preoperative predictors of PPHG in subjects spontaneously self-reporting PPHG after RYGB or LSG. Patients, Setting, and Intervention: Nondiabetic patients spontaneously self-reporting symptoms/signs of PPHG (PPHG group, 21 RYGB and 11 LSG) were compared in a case-control design with subjects who never experienced spontaneous or oral glucose tolerance test (OGTT)-induced hypoglycemia over 24 months after surgery (No-PPHG group, 13 RYGB and 40 LSG). Paired pre- and postoperative 3-hour OGTTs were analyzed in all participants.

MAIN OUTCOME MEASURES

Insulin sensitivity was assessed by the oral glucose insulin sensitivity index and β-cell function by mathematical modeling of the C-peptide response to glucose.

RESULTS

Before surgery, the body mass index was lower in PPHG than No-PPHG patients in the RYGB (P = .002) and trended similarly in the LSG group (P = .08). Fasting glycemia and the glucose-OGTT nadir were lower in the PPHG than the No-PPHG subjects in both surgery groups. Before surgery, insulin sensitivity was higher in PPHG than No-PPHG in the RYGB (393 ± 55 vs 325 ± 44 mL/min^-1 · m^-2, P = .001) and LSG groups (380 ± 48 vs 339 ± 60 mL/min^-1 · m^-2, P = .05) and improved to a similar extent in all groups after surgery. Before surgery, β-cell glucose sensitivity was higher in PPHG than No-PPHG in both RYGB (118 ± 67 vs 65 ± 24 pmol/min^-1 · m² · mM^-1) and LSG patients (114 ± 32 vs 86 ± 33) (both P = .02) and improved in all subjects after surgery.

CONCLUSIONS

In subjects self-reporting PPHG after surgery, lower presurgery plasma glucose concentrations, higher insulin sensitivity, and better β-cell glucose sensitivity are significant predictors of PPHG after both RYGB and LSG.

Post-gastric bypass hypoglycaemia: a review

Bariatric surgery is a highly effective treatment for severe obesity, resulting in substantial weight loss and normalizing obesity-related comorbidities. However, long-term consequences can occur, such as postbariatric surgery hypoglycaemia. This is a challenging medical problem, and the number of patients presenting with it has been increasing. Roux-en-Y gastric bypass (RYGB) is the most popular bariatric procedure, and it is the surgery most commonly associated with the development of postbariatric surgery hypoglycaemia. To date, the pathogenesis of this condition has not been completely established. However, various factors - particularly increased postprandial glucagon-like peptide (GLP)-1 secretion - have been considered as crucial mediator. The mechanisms responsible for diabetic remission after bariatric surgery may be responsible for the development of hypoglycaemia, which typically occurs 1-3 h after a meal and is concurrent with inappropriate hyperinsulinaemia. Carbohydrate-rich foods usually provoke hypoglycaemic symptoms, which can typically be alleviated by strict dietary modifications, including carbohydrate restriction and avoidance of high glycaemic index foods and simple sugars. Few patients require further medical intervention, such as medications, but some patients have required a pancreatectomy. Because this option is not always successful, it is no longer routinely recommended. Clinical trials are needed to further determine the pathophysiology of this condition as well as the best diagnostic and treatment approaches for these patients.

Effects of meal composition on postprandial incretin, glucose and insulin responses after surgical and medical weight loss

Background

Meal tolerance tests are frequently used to study dynamic incretin and insulin responses in the postprandial state; however, the optimal meal that is best tolerated and suited for hormonal response following surgical and medical weight loss has yet to be determined.

Objective

To evaluate the tolerability and effectiveness of different test meals in inducing detectable changes in markers of glucose metabolism in individuals who have undergone a weight loss intervention.

Methods

Six individuals who underwent surgical or medical weight loss (two Roux‐en‐Y gastric bypass, two sleeve gastrectomy and two medical weight loss) each completed three meal tolerance tests using liquid‐mixed, solid‐mixed and high‐fat test meals. The tolerability of each test meal, as determined by the total amount consumed and palatability, as well as fasting and meal‐stimulated glucagon‐like peptide, glucose‐dependent insulinotropic polypeptide, insulin and glucose were measured.

Results

Among the six individuals, the liquid‐mixed meal was better and more uniformly tolerated with a median meal completion rate of 99%. Among the four bariatric surgical patients, liquid‐mixed meal stimulated on average a higher glucagon‐like peptide (percent difference: 83.7, 89), insulin secretion (percent difference: 155.1, 158.7) and glucose‐dependent insulinotropic polypeptide (percent difference: 113.5, 34.3) compared with solid‐mixed and high‐fat meals.

Conclusions

The liquid‐mixed meal was better tolerated with higher incretin and insulin response compared with the high‐fat and solid‐mixed meals and is best suited for the evaluation of stimulated glucose homeostasis.

Bariatric and metabolic surgery: current trends and what's to follow

PURPOSE OF REVIEW

Obesity is a global epidemic and bariatric surgery remains an underperformed modality for its treatment. Even though the dangers of obesity are well understood, surgical intervention is underestimated. The purpose of this review is to discuss emerging trends in bariatric surgery.

RECENT FINDINGS

Studies suggest that different operations have different effects on both obesity and its comorbidities. Combining the concepts of malabsorption and restriction, we are looking toward more advanced and efficient treatment options. Less-invasive techniques such as endoscopic devices are under investigation and their results remain to be determined.

SUMMARY

A paradigm shift is occurring and both obesity and diabetes will be increasingly treated with surgical and endoscopic procedures. Bariatric care is a growing field for surgeons and therapeutic endoscopists with many future opportunities for improvement.

Diagnostic tools for post-gastric bypass hypoglycaemia

In spite of its evident success, several late complications can occur after gastric bypass surgery. One of these is post-gastric bypass hypoglycaemia. No evidence-based guidelines exist in the literature on how to confirm the presence of this syndrome. This study aims to describe and compare the tests aimed at making a diagnosis of post-gastric bypass hypoglycaemia and to provide a diagnostic approach based upon the available evidence. A search was conducted in PubMed, Cochrane and Embase. A few questionnaires have been developed to measure the severity of symptoms in post-gastric bypass hypoglycaemia but none has been validated. The gold standard for provocation of a hypoglycaemic event is the oral glucose tolerance test or the liquid mixed meal tolerance test. Both show a high prevalence of hypoglycaemia in post-gastric bypass patients with and without hypoglycaemic complaints as well as in healthy volunteers. No uniformly established cut-off values for glucose concentrations are defined in the literature for the diagnosis of post-gastric bypass hypoglycaemia. For establishing an accurate diagnosis of post-gastric bypass hypoglycaemia, a validated questionnaire, in connection with the diagnostic performance of provocation tests, is the most important thing missing. Given these shortcomings, we provide recommendations based upon the current literature.

Relationship between gastric pouch and weight loss after laparoscopic sleeve gastrectomy

BACKGROUND

Laparoscopic sleeve gastrectomy (LSG) is considered safe and effective even as conversion procedure after primary bariatric operations. The correlation between gastric pouch volumes and patients weight loss remains unclear.

METHODS

To assess a correlation between the gastric remnant size and the weight loss, we reviewed 49 consecutive barium swallow UGS performed at our institute from August 2012 through May 2014 in LSG patients with symptoms and/or unsatisfactory weight loss. The anteroposterior (AP), laterolateral (LL) and vertical (CC) diameters of the gastric pouch were measured to calculate the volume by the formula of the ellipsoid (AP × LL × CC × 0.5). Patients were divided in two groups: group 1 without gastric pouch (n = 36) and group 2 with gastric pouch (n = 13). Correlation between pouch volume and weight loss data was calculated with t Student's and Fisher tests to compare the percent excess body mass index (BMI) and percent excess body mass loss (EBL) between two groups, and P < 0.05 was considered statistically significant.

RESULTS

The mean percent EBL was 26.54 ± 11.02 and 27.12 ± 12.35 kg/m(2) in groups with and without pouch, respectively. The mean volume of the pouch after LSG was 17.13 ± 21.56 mm(3). Pouch volume, when present, was not significantly correlated to weight loss (P = 0.88 95% CI, CL 19.88-33.20 group 2; CL 22.94-31.30 group 1).

CONCLUSIONS

No statistical correlation was found between the volume of the gastric pouch and weight loss (percent EBL) after LSG in symptomatic or with unsatisfactory weight loss patients.

Hypoglycemia in everyday life after gastric bypass and duodenal switch

DESIGN

Gastric bypass (GBP) and duodenal switch (DS) in morbid obesity are accompanied by marked metabolic improvements, particularly in glucose control. In recent years, episodes of severe late postprandial hypoglycemia have been increasingly described in GBP patients; data in DS patients are scarce. We recruited three groups of subjects; 15 GBP, 15 DS, and 15 non-operated overweight controls to examine to what extent hypoglycemia occurs in daily life.

METHODS

Continuous glucose monitoring (CGM) was used during 3 days of normal activity. The glycemic variability was measured by mean amplitude of glycemic excursion and continuous overall net glycemic action. Fasting blood samples were drawn, and the patients kept a food and symptom log throughout the study.

RESULTS

The GBP group displayed highly variable CGM curves, and 2.9% of their time was spent in hypoglycemia (<3.3  mmol/l, or 60  mg/dl). The DS group had twice as much time in hypoglycemia (5.9%) and displayed CGM curves with little variation as well as lower HbA1c levels (29.3 vs 35.9 mmol/mol, P<0.05). Out of a total of 72 hypoglycemic episodes registered over the 3-day period, 70 (97%) occurred in the postprandial state and only about one-fifth of the hypoglycemic episodes in the GBP and DS groups were accompanied by symptoms. No hypoglycemias were seen in controls during the 3-day period.

CONCLUSION

Both types of bariatric surgery induce marked, but different, changes in glucose balance accompanied by frequent, but mainly unnoticed, hypoglycemic episodes. The impact and mechanism of hypoglycemic unawareness after weight-reduction surgery deserves to be clarified.

A prospective evaluation of the influence of three bariatric procedures on insulin resistance improvement. Should the extent of undiluted bile transit be considered a key postoperative factor altering glucose metabolism?

INTRODUCTION

Insulin resistance (IR), the essential step in development of type 2 diabetes mellitus (T2DM), resolves quickly after bariatric surgery, but the effectiveness depends on the type of the procedure. Although the long-term influence on IR improvement is well documented, the mechanisms of the ultra-fast response after restrictive and bypass procedures require explanation.

AIM

To determine IR evolution from the initial preparative period to 6 months after the operation, exposing the rapid postoperative response while comparing the 3 bariatric methods, with the belief that the metabolic effect may be correlated with anatomical combinations.

MATERIAL AND METHODS

From January to December, 2013, a cohort of severely obese, insulin resistant individuals recruited to the prospective study underwent laparoscopic sleeve gastrectomy (SG-30), Roux-en-Y gastric bypass (RYGB-30) and one-anastomosis gastric bypass (OAGB-30). Main laboratory parameters of glucose metabolism were evaluated in fasting patients preoperatively, 4 days and 1, 3 and 6 months after surgery.

RESULTS

Within the whole observation period the most significant improvement in homeostasis model assessment for IR (HOMA-IR) was observed in the first 4 days after each operation. The decrease of HOMA-IR was higher (p < 0.0001) in gastric bypass groups than in patients after SG (-41%). The difference between bypass groups favors OAGB over RYGB (63 vs. -56%, p = 0.0489).

CONCLUSIONS

Among all bariatric management factors, operation type is the most important in IR improvement. The significant difference in response after SG vs. RYGB and OAGB supports the concept of metabolic competence of duodeno-jejunal exclusion. Altered bile flow after duodeno-jejunal exclusion may be responsible for enhanced glucose metabolism improvement.

Weight loss by calorie restriction versus bariatric surgery differentially regulates the hypothalamo-pituitary-adrenocortical axis in male rats

Behavioral modifications for the treatment of obesity, including caloric restriction, have notoriously low long-term success rates relative to bariatric weight-loss surgery. The reasons for the difference in sustained weight loss are not clear. One possibility is that caloric restriction alone activates the stress-responsive hypothalamo-pituitary-adrenocortical (HPA) axis, undermining the long-term maintenance of weight loss, and that this is abrogated after bariatric surgery. Accordingly, we compared the HPA response to weight loss in five groups of male rats: (1) high-fat diet-induced obese (DIO) rats treated with Roux-en-Y gastric bypass surgery (RYGB, n = 7), (2) DIO rats treated with vertical sleeve gastrectomy (VSG, n = 11), (3) DIO rats given sham surgery and subsequently restricted to the food intake of the VSG/RYGB groups (Pair-fed, n = 11), (4) ad libitum-fed DIO rats given sham surgery (Obese, n = 11) and (5) ad libitum chow-fed rats given sham surgery (Lean, n = 12). Compared with Lean controls, food-restricted rats exhibited elevated morning (nadir) non-stress plasma corticosterone concentration and increased hypothalamic corticotropin-releasing hormone and vasopressin mRNA expression, indicative of basal HPA activation. This was largely prevented when weight loss was achieved by bariatric surgery. DIO increased HPA activation by acute (novel environment) stress and this was diminished by bariatric surgery-, but not pair-feeding-, induced weight loss. These results indicate that the HPA axis is differentially affected by weight loss from caloric restriction versus bariatric surgery, and this may contribute to the differing long-term effectiveness of these two weight-loss approaches.

Effects of duodenal switch alone or in combination with sleeve gastrectomy on body weight and lipid metabolism in rats

BACKGROUND

A combined procedure of sleeve gastrectomy and duodenal switch (SG+DS) has been applied to the treatment of super obesity. The aim of the present study was to test whether duodenal switch alone (DS) leads to similar weight loss and changes in lipid metabolism as SG+DS.

METHODS

Male Sprague-Dawley rats underwent sham surgery (Sham, N=7), duodenal switch alone (DS, N=5) or sleeve gastrectomy followed by duodenal switch (SG+DS, N=5). Body weight, feed and water intakes, and ambulatory activity were recorded 2 months post surgery. Tissue and faecal lipids, faecal bile acids, plasma cytokines and lipid metabolism-related gene expression in adipose tissue and liver were analysed.

RESULTS

Daily energy intake, relative feed uptake, ambulatory activity and body weight reduction were similar between DS and SG+DS rats. The hepatic triacylglycerol content was higher and faecal secretion of triacylglycerol was lower after SG+DS compared to DS (P<0.05). Faecal bile acid secretion was higher in SG+DS than in DS rats (P<0.05) despite similar hepatic CYP7A1mRNA level. Plasma levels of proinflammatory cytokines interleukin (IL)-1b, IL-2, IL-4, IL-5, IL-6, IL-12, granulocyte-macrophage colony stimulating factor and tumour necrosis factor alpha were higher in SG+DS than in DS rats (P<0.05).

CONCLUSIONS

Although DS and SG+DS had similar efficacy in terms of body weight loss, SG+DS resulted in a poorer regulation of lipid metabolism than DS.