Differences in Weight Loss and Gut Hormones: Rouen-Y Gastric Bypass and Sleeve Gastrectomy Surgery

Are the Changes in Gastrointestinal Hormone Secretion Necessary for the Success of Bariatric Surgery? A Critical Review of the Literature

Ghrelin, glucagon-like peptide-1 (GLP-1), and peptide YY (PYY) are involved in energy balance regulation and glucose homeostasis. Obesity is characterized by lower fasting levels and blunted postprandial responses of ghrelin, GLP-1, and possibly PYY. Both Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) have been shown to increase postprandial GLP-1 and PYY levels. Human studies have shown that enhanced postprandial GLP-1 and PYY release are associated with favorable weight loss outcomes after RYGB. However, studies in knockout mice have shown that GI hormones are not required for the primary metabolic effects of bariatric surgery. Here, we summarize the complex interaction between obesity, bariatric surgery, and GI hormones in order to determine the exact role of GI hormones in the success of bariatric surgery.

Factors Related to Weight Loss Maintenance in the Medium-Long Term after Bariatric Surgery: A Review

Despite bariatric surgery being the most effective treatment for obesity, some individuals do not respond adequately, especially in the long term. Identifying the predictors of correct weight maintenance in the medium (from 1 to 3 years after surgery) and long term (from 3 years and above) is of vital importance to reduce failure after bariatric surgery; therefore, we summarize the evidence about certain factors, among which we highlight surgical technique, psychological factors, physical activity, adherence to diet, gastrointestinal hormones or neurological factors related to appetite control. We conducted a search in PubMed focused on the last five years (2015–2021). Main findings are as follows: despite Roux-en-Y gastric bypass being more effective in the long term, sleeve gastrectomy shows a more beneficial effectiveness–complications balance; pre-surgical psychological and behavioral evaluation along with post-surgical treatment improve long-term surgical outcomes; physical activity programs after bariatric surgery, in addition to continuous and comprehensive care interventions regarding diet habits, improve weight loss maintenance, but it is necessary to improve adherence; the impact of bariatric surgery on the gut–brain axis seems to influence weight maintenance. In conclusion, although interesting findings exist, the evidence is contradictory in some places, and long-term clinical trials are necessary to draw more robust conclusions.

Bone Mineral Density and Turnover After Sleeve Gastrectomy and Gastric Bypass: A Randomized Controlled Trial (Oseberg)

CONTEXT

Bariatric surgery, particularly Roux-en-Y gastric bypass (RYGB), is associated with an increased risk of osteoporotic fractures. It is unknown whether RYGB or sleeve gastrectomy (SG) have different effects on bone health.

OBJECTIVE

To compare changes in bone mineral density and markers of bone turnover 1 year after SG and RYGB.

DESIGN, SETTING, PATIENTS, AND INTERVENTIONS

Randomized, triple-blind, single-center trial at a tertiary care center in Norway. The primary outcome was diabetes remission. Patients with severe obesity and type 2 diabetes were randomized and allocated (1:1) to SG or RYGB.

MAIN OUTCOME MEASURES

Changes in areal bone mineral density (aBMD) and bone turnover markers.

RESULTS

Femoral neck, total hip, and lumbar spine aBMD, but not total body aBMD, decreased significantly more after RYGB (n = 44) than after SG (n = 48) (mean [95% confidence interval] between group differences -2.8% [-4.7 to -0.8], -3.0% [-5.0 to -0.9], -4.2% [-6.4 to -2.1], and -0.5% [-1.6 to 0.6], respectively). The increase in procollagen type 1 N-terminal propeptide (P1NP) and C-telopeptide of type I collagen (CTX-1) were approximately 100% higher after RYGB than after SG (between group difference at 1 year, both P < 0.001). The changes in femoral neck, total hip, and lumbar spine aBMDs and the changes in P1NP and CTX-1 were independently associated with the surgical procedure (all P < 0.05) and not weight change.

CONCLUSIONS

Roux-en-Y gastric bypass was associated with a greater reduction in aBMD and a greater increase in bone turnover markers compared with SG. This finding could suggest greater skeletal fragility after RYGB.

Disordered eating and weight loss after bariatric surgery

PURPOSES

Aberrant eating patterns are frequently observed in bariatric patients. Since bariatric operations produce alterations in food transit and in appetite/satiety balance, postoperative eating behavior changes are not surprising.

METHODS

88 consecutive obese patients undergoing Roux-en-Y gastric bypass (RYGBP, 50 cases) and Sleeve Gastrectomy (SG, 38 cases) were retrospectively evaluated. Beside anthropometric data measurement, eating behavior was assessed by direct interview prior to the operation and at the first and second postoperative years: patients were considered as eating disordered (ED) when referred habitual occurrence of binge eating and nibbling/grazing. Weight loss was assessed by percent of BMI loss (% Δ BMI). Together with standard follow-up, patients received additional behavioral/dietetic support upon request.

RESULTS

Postoperative ED patients showed lower % Δ BMI than the not ED ones at one (30.7% ± 8,5 vs. 26.8% ± 10, p < 0.02) and two (32% ± 10.3 vs. 27.4% ± 12.9, p < 0.05) years after operation, the follow-up rate being 82% and 76%, respectively, without differences between RYGBP and SG group. After RYGBP, an improvement of eating behavior was observed (ED patients from 75 to 28% at 1 year and to 27% at 2 years), while no changes were observed after SG. In SG patients, the number of additional behavioral/dietetic support sessions throughout the follow-up was positively associated with % Δ BMI.

DISCUSSION

The postoperative normalization of eating pattern has a role in weight loss after bariatric surgery. Behavioral/dietetic support is indicated in all SG patient, while after RYGBP is useful only when weight loss is unsatisfactory.

LEVEL OF EVIDENCE

III: retrospective cohort study.

Short-term interval exercise suppresses acylated ghrelin and hunger during caloric restriction in women with obesity

Caloric restriction is suggested to increase hunger, in part, through complex interactions of hormones and behavior that contribute to challenges in long-term weight loss. Although intense exercise may attenuate appetite, no data exist testing the effects of interval exercise (INT) during a low-calorie diet (LCD) on appetite regulation. We hypothesized that LCD+INT would favorably influence satiety when compared with an energy-deficit matched LCD in women with obesity. Twenty-six women with obesity (47.3±2.4 yrs; 37.3 ± 1.2 kg/m2) were randomized to either LCD (n = 13; mixed meals of ~1200 kcal/d) or LCD+INT (n = 13; 60 min/d of supervised interval exercise at 90% HRpeak for 3 min and 50% HRpeak for 3 min) for 2 weeks. An additional 350kcal (shake) was provided to LCD+INT individuals post-exercise to equate energy availability between groups. Total PYY, acylated ghrelin and des-ghrelin were measured at 0, 30 and 60 min of a 75g OGTT before and after the intervention. Visual analog scales were also administered at 0 and 120 min of the OGTT to assess appetite perception. Food logs were recorded prior to and during the intervention to ensure caloric intake compliance. Compared with pre-intervention conditions, both interventions decreased food intake (P = 0.001) and body fat (P < 0.01). There was no effect on fasting PYY, but both LCD and LCD+INT increased post-prandial PYY iAUC (P < 0.001) relative to pre-intervention. LCD+INT maintained fasting acylated ghrelin (P = 0.06) and suppressed post-prandial acylated ghrelin iAUC (P = 0.04) compared to LCD. Neither intervention impacted circulating des- ghrelin before or following the OGTT. Interestingly, LCD+INT attenuated fasting hunger and maintained fullness compared with LCD (P = 0.05 and P = 0.06, respectively). Taken together, interval exercise favors acylated ghrelin suppression and perception of hunger during a LCD in women with obesity.

Effects of the Postoepartive Dietetic/Behavioral Counseling on the Weight Loss After Bariatric Surgery

OBJECTIVE

Weight outcomes after bariatric surgery are due to an adequate adjustment of eating behavior to the new gastrointestinal conditions created by operation. The efficacy of dietary/behavior counseling for promoting weight loss and maintenance in a growing number of bariatric patients was investigated.

MATERIAL AND METHODS

One hundred seventy-six non-diabetic obese patients undergoing Roux-en-Y gastric bypass (RYGBP) and sleeve gastrectomy (SG) were investigated. The first group (CO, 88 subjects, 16 male) attended a standard surgical follow-up, while in the second (DIET, 88 subjects, 15 male) the surgeon was supported by a dietitian, and patients received behavioral-dietary sessions on individual request. Data prior to the operation and at 2 years were considered, the weight outcome being regarded as successful when postoperative body mass index (BMI) value was lower than 30 kg/m².

RESULTS

Weight results were better (p < 0.01) in the RYGBP than in the SG patients. In comparison to CO, in the DIET group a greater adherence to the bariatric program was observed (76% vs. 41%, < 0.01), while body weight data and prevalence of successful cases at 2 years (87 ± 23 vs. 83 ± 16 kg and 27% vs.33%, respectively) were similar.

CONCLUSIONS

After RYSG and SG, postoperative dietetic/behavioral sessions delivered on patient's request does not influence weight results. The dietetic intervention promotes the adherence to bariatric program and prevents postoperative follow-up loss. In a dietitian/behavioral strategy after RYGBP and SG, a cognitive reinforcement of the compliance to bariatric program and a strengthening of the motivation to changes could promote better weight results.

Is Concomitant Cholecystectomy Necessary for Asymptomatic Cholelithiasis During Laparoscopic Sleeve Gastrectomy?

BACKGROUND

There is not any consensus on concomitant cholecystectomy for asymptomatic gallbladder stones during laparoscopic sleeve gastrectomy (LSG). The aim of this study was to evaluate the surveillance results of the LSG patients who have asymptomatic gallbladder stones and did not undergo cholecystectomy.

METHODS

Patients who underwent laparoscopic sleeve gastrectomy with preoperatively detected gallbladder stones and completed at least 6 months follow-up were included in the study. Concomitant cholecystectomy was performed for symptomatic patients while it was not performed for asymptomatic subjects. At the end of the follow-up time, symptoms and signs related to gallbladder disease were recorded. Clinical and demographic characteristics were compared between symptomatic and asymptomatic patients.

RESULTS

Between February 2012 and October 2016, 312 laparoscopic sleeve gastrectomies were performed. Among the patients, 24 were regarded as asymptomatic cholelithiasis, and cholecystectomy was not performed. The mean follow-up period was 27 (6-58) months. The mean preoperative BMI was 50.0 ± 7.6 kg/m², and at the end of the follow-up time, it decreased to 35.6 ± 8.8 kg/m². Five (20.8%) patients experienced biliary colic. Acute cholecystitis or obstructive jaundice was not observed in any of the patients. Characteristics of patients who developed symptomatic gallbladder disease (n = 5) were not significantly different from those of patients who remained asymptomatic (n = 19).

CONCLUSIONS

The risk of becoming symptomatic for asymptomatic cholelithiasis is very close to the healthy population after sleeve gastrectomy. Although further studies with a high number of cases are needed, we suggest only observation for asymptomatic gallbladder stones in patients who will undergo sleeve gastrectomy.

Effect of laparoscopic Roux-en-Y gastric bypass versus laparoscopic sleeve gastrectomy on fasting gastrointestinal and pancreatic peptide hormones: A prospective nonrandomized trial

BACKGROUND

Changes in gastrointestinal and pancreatic hormones may play a role in promoting long-term weight reduction and improved glucose metabolism after sleeve gastrectomy and Roux-en-Y gastric bypass. However, few studies have examined the metabolic and endocrine effects of these procedures in Mainland China.

OBJECTIVES

To compare the effects of laparoscopic sleeve gastrectomy (LSG) and laparoscopic Roux-en-Y gastric bypass (LRYGB) on gastrointestinal and pancreatic peptide hormones.

SETTING

University hospital, China.

METHODS

A nonrandomized prospective study was conducted in Chinese obese patients undergoing LSG or LRYGB. Of 20 patients in this study, 10 underwent LSG, and 10 underwent LRYGB. Fasting plasma levels of insulin, glucagon, ghrelin, gastric inhibitory peptide, peptide YY, glucagon-like peptide (GLP)-1, and GLP-2 were measured preoperatively and at 1, 3, 6, and 12 months after surgery. This trial was registered at www.clinicaltrials.gov (NCT02963662).

RESULTS

During the first year after both operations, mean body mass index and fasting insulin levels steadily decreased at all intervals. Fasting plasma glucose levels significantly decreased at 1 month after surgery, then remained stable in both groups. Glucagon levels significantly decreased at 1, 3, and 6 months after surgery in both groups, but returned to baseline at 12 months. Fasting GLP-1 and peptide YY significantly increased in both groups, but more so after LRYGB. However, GLP-2 did not change in either group. Ghrelin levels significantly decreased after LSG, but not after LRYGB. Gastric inhibitory peptide levels decreased after LRYGB but not after LSG.

CONCLUSIONS

LSG and LRYGB resulted in significant and distinct changes in multiple gastrointestinal and pancreatic peptide hormones that are important regulators of obesity and metabolic health.

Fasting and postprandial acyl and desacyl ghrelin and the acyl/desacyl ratio in obese patients before and after different types of bariatric surgery

Introduction

The mechanism underlying beneficial outcomes of bariatric surgery still remains unclear. Especially little is known about hormonal and metabolic changes induced by the novel bariatric procedure mini gastric bypass (MGB).

Aim

To evaluate pre- and post-prandial changes in both ghrelin isoforms in obese patients without diabetes and cardiovascular complications treated with MGB, sleeve gastrectomy (SG) or Roux-en-Y gastric bypass (RYGB) surgery.

Material and methods

From 45 patients initially enrolled in the study, 23 persons completed a one-year follow-up period. Venous blood for acyl and desacyl ghrelin (AG and DAG) as well as other metabolic assays was collected 3 months before and 6 and 12 months after bariatric surgery (MGB, RYGB, SG) – in the fasting state and 2 h after the consumption of a standard 300 kcal-mixed meal (Nutridrink standard, Nutricia).

Results

AG and DAG levels (both fasting and prandial) as well as AG/DAG ratio did not change after 6 and 12 months in MGB and RYGB groups. In the SG group we observed a significant decrease in fasting and postprandial DAG levels and consecutively an increase in the fasting AG/DAG ratio after 6 and 12 months. Six months after surgery we observed some differences between carbohydrate metabolism measures in the MGB group (lower HbA_1c, HOMA-IR and fasting insulinaemia) in comparison to the rest of the participants, but 12 months after each type of surgery body mass index and indices of carbohydrate and lipid metabolism did not differ.

Conclusions

The results of our study demonstrate that all studied bariatric procedures can successfully reduce overall body weight and suggest also that the mechanisms of weight loss and improvement in carbohydrate and lipid metabolism after all three types of surgery are independent of ghrelin and the acyl/desacyl ghrelin ratio.

Does previous abdominal surgery affect the course and outcomes of laparoscopic bariatric surgery?

BACKGROUND

Global experiences in general surgery suggest that previous abdominal surgery may negatively influence different aspects of perioperative care. As the incidence of bariatric procedures has recently increased, it is essential to assess such correlations in bariatric surgery.

OBJECTIVES

To assess whether previous abdominal surgery influences the course and outcomes of laparoscopic bariatric surgery.

SETTING

Seven referral bariatric centers in Poland.

METHODS

We conducted a retrospective analysis of 2413 patients; 1706 patients who underwent laparoscopic sleeve gastrectomy (SG) or Roux-en-Y gastric bypass (RYGB) matched the inclusion criteria. Patients with no history of abdominal surgery were included as group 1, while those who had undergone at least 1 abdominal surgery were included as group 2.

RESULTS

Group 2 had a significantly prolonged median operation time for RYGB (P = .012), and the longest operation time was observed in patients who had previously undergone surgeries in both the upper and lower abdomen (P = .002). Such a correlation was not found in SG cases (P = .396). Groups 1 and 2 had similar rates of intraoperative adverse events and postoperative complications (P = .562 and P = .466, respectively). Group 2 had a longer median duration of hospitalization than group 1 (P = .034), while the readmission rate was similar between groups (P = .079). There was no significant difference between groups regarding the influence of the long-term effects of bariatric treatment on weight loss (percentage of follow-up was 55%).

CONCLUSIONS

Previous abdominal surgery prolongs the operative time of RYGB and the duration of postoperative hospitalization, but does not affect the long-term outcomes of bariatric treatment.

Serum Leptin, Obestatin, and Ghrelin Levels and Gastric Emptying Rates of Liquid and Solid Meals in Non-obese Rats with Roux-en-Y Bypass Surgery or Prosthesis Placement: Implications for the Role of Vagal Afferents

BACKGROUND

The present study aimed to investigate the effects of Roux-en-Y gastric bypass (RYGB) and prosthesis placement on gastric emptying rate in conjunction with serum ghrelin-obestatin-leptin responses in non-obese rats with intact or denervated afferent innervation.

METHODS

Under anesthesia, male Sprague-Dawley rats underwent either sham operation, RYGB, prosthesis, and/or Gregory cannula placement. Three weeks later, liquid or solid gastric emptying tests were performed and serum ghrelin, leptin and obestatin levels were measured.

RESULTS

Both prosthesis placement and RYGB surgery delayed non-nutrient liquid emptying; while solid nutrient emptying was delayed only by RYGB. Nutrient-dependent (acid, hyperosmolal and peptone) delay in liquid emptying was abolished in rats with prosthesis. By vagal afferent denervation, delayed liquid emptying was abolished, while solid emptying was further delayed in rats with prosthesis. Ghrelin and obestatin levels were depressed in prosthesis-placed rats, but RYGB surgery had no impact on both levels. Leptin level was elevated in solid-food-given rats with prosthesis, but not changed in RYGB group, while it was reduced following liquid meal. All the changes observed in ghrelin, obestatin, or leptin levels in response to meal ingestion were reversed with vagal afferent denervation.

CONCLUSIONS

Both RYGB and prosthesis placement had delaying effects on gastric emptying rate of non-obese rats. Our results indicate that the short-term changes in gastric motility and hormone responses induced by volume reduction are reversed by afferent denervation, suggesting that sparing the vagal innervation could be essential for reaching optimum motility and hormone changes expected after bariatric surgery.

An Overview of Dietary Interventions and Strategies to Optimize the Management of Non-Alcoholic Fatty Liver Disease

Aim: To investigate the efficacy of lifestyle adjustment strategies as a preventive measure and/or treatment of obesity-related non-alcoholic fatty liver disease in adults. Method: A systematic review of literature through 1 July 2017 on the PubMed Database was performed. A comprehensive search was conducted using key terms, such as non-alcoholic fatty liver disease (NAFLD), combined with lifestyle intervention, diet, and exercise. All of the articles and studies obtained from the search were reviewed. Redundant literature was excluded. Results: Several types of dietary compositions and exercise techniques were identified. Most studies concluded and recommended reduction in the intake of saturated and trans fatty acids, carbohydrates, and animal-based protein, and increased intake of polyunsaturated fatty acids (PUFAs), monounsaturated fatty acids (MUFAs), plant-based proteins, antioxidants, and other nutrients was recommended. The Mediterranean and Paleo diet both seem to be promising schemes for NAFLD patients to follow. Exercise was also encouraged, but the type of exercise did not affect its efficacy as a NAFLD treatment when the duration is consistent. Conclusions: Although these different dietary strategies and exercise regimens can be adopted to treat NAFLD, current literature on the topic is limited in scope. Further research should be conducted to truly elucidate which lifestyle adjustments individually, and in combination, may facilitate patients with obesity-related NAFLD.

Body Weight Reduction and Biochemical Parameters of the Patients After RYGB and SG Bariatric Procedures in 12-Month Observation

Background

The aim of this study was to evaluate the effect of sleeve gastrectomy (SG) and Roux-en-Y-bypass (RYGB) on anthropometric and biochemical parameters, including changes in glucose levels, lipid profile and liver function. Drastic decrease in all lipid fractions a few weeks or months after the surgery could be regarded as favourable, but low level of HDL is an independent risk factor for heart diseases. Extreme load on the liver without preparation of the patient to the surgery can have negative consequences.

Methods

The test group comprised of 40 female patients at the age of 42.96 with average body weight of 131.56 kg and BMI 46.49. Biochemical analyses were performed using calorimetric method.

Results

No statistically significant differences were observed in glucose levels between the two types of procedures. The highest differences were noted for triglycerides levels, which decreased, as well as all cholesterol fractions, after RYGB, but were increasing during the first months after SG procedure. Changes in lipid profile, caused by the reduction of all lipid fractions, were more visible after RYGB. The decrease in total cholesterol directly and activity of liver enzymes after the procedure was as higher after RYGB as after SG. Increased activity of transaminases indicates significant liver overload.

Conclusions

With the selection of groups of patients with similar initial parameters, it is not clear whether the differences between the two procedures when assessing the improvement of glycaemia are significant. However, due to invasive character of RYGB, liver overload lasting several months and lifelong limited absorption of nutrients, the possibility of SG procedure should be considered as a first option.

Critical role for GLP-1 in symptomatic post-bariatric hypoglycaemia

AIMS/HYPOTHESIS

Post-bariatric hypoglycaemia (PBH) is a rare, but severe, metabolic disorder arising months to years after bariatric surgery. It is characterised by symptomatic postprandial hypoglycaemia, with inappropriately elevated insulin concentrations. The relative contribution of exaggerated incretin hormone signalling to dysregulated insulin secretion and symptomatic hypoglycaemia is a subject of ongoing inquiry. This study was designed to test the hypothesis that PBH and associated symptoms are primarily mediated by glucagon-like peptide-1 (GLP-1).

METHODS

We conducted a double-blinded crossover study wherein eight participants with confirmed PBH were assigned in random order to intravenous infusion of the GLP-1 receptor (GLP-1r) antagonist. Exendin (9-39) (Ex-9), or placebo during an OGTT on two separate days at the Stanford University Clinical and Translational Research Unit. Metabolic, symptomatic and pharmacokinetic variables were evaluated. Results were compared with a cohort of BMI- and glucose-matched non-surgical controls (NSCs).

RESULTS

Infusion of Ex-9 decreased the time to peak glucose and rate of glucose decline during OGTT, and raised the postprandial nadir by over 70%, normalising it relative to NSCs and preventing hypoglycaemia in all PBH participants. Insulin AUC and secretion rate decreased by 57% and 71% respectively, and peak postprandial insulin was normalised relative to NSCs. Autonomic and neuroglycopenic symptoms were significantly reduced during Ex-9 infusion.

CONCLUSIONS/INTERPRETATION

GLP-1r blockade prevented hypoglycaemia in 100% of individuals, normalised beta cell function and reversed neuroglycopenic symptoms, supporting the conclusion that GLP-1 plays a primary role in mediating hyperinsulinaemic hypoglycaemia in PBH. Competitive antagonism at the GLP-1r merits consideration as a therapeutic strategy.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02550145.

The evolving role of bariatric surgery in patients with type 1 diabetes and obesity

Bariatric surgery has emerged as a viable treatment option in morbidly obese individuals with type 2 diabetes. Concomitant with societal lifestyle changes and the increased emphasis on achieving metabolic targets, there has been a rise in the number of patients with type 1 diabetes (T1DM) who are overweight and obese. Preliminary experience based on a limited number of observational reports points to substantial weight loss and amelioration of comorbid conditions such as blood pressure and dyslipidemia in patients with T1DM who undergo weight loss surgery. However, there is little evidence to suggest significant improvement in glycemic control and lowering of glycosylated hemoglobin, and bariatric surgical procedures do not necessarily lead to enhanced diabetes management. and improved quality of life. The potential possibility of micronutrient deficiency, weight regain, and psychobehavioral issues post-bariatric surgery also exists. An individualized evaluation of the risks and benefits should be considered, using a a multidisciplinary team approach with expertise in patient selection, surgical technique, and follow-up. A crucial component is the availability of a diabetes care specialist or endocrinologist experienced in intensive, tailored, modifiable insulin regimens who maintains close and careful monitoring during all phases of management. Reliable data from a prospective, longitudinal perspective is required to provide guidelines for clinicians and informed choices for obese patients with T1DM who are contemplating bariatric surgery.