High ghrelin concentration is not a predictor of less weight loss in morbidly obese women treated with laparoscopic adjustable gastric banding

Baseline circulating ghrelin does not predict weight regain neither maintenance of weight loss after gastric bypass at long term

BACKGROUND

Predictors of weight loss (WL) or weight regain (WR) after Roux-en-Y gastric bypass (RYGBP) are not established. The aim of this study was to analyze the usefulness of some baseline peptides (leptin, insulin, and ghrelin) as biomarkers of WL and WR in morbid obese patients after RYGBP at long term.

METHODS

Seventy-six morbid obese (47 women, age 41.6 ± 9.6 years, body mass index [BMI] 52.1 ± 8 kg/m(2)) patients were evaluated at baseline and at 1, 2, and 6 years after surgery.

RESULTS

Excess body weight loss after 6 years was of 63.9%. Age, BMI, and studied hormones at baseline or their changes over time did not predict long-term excess body weight loss. WR greater than 10% was observed in 36.8% of patients between 2 and 6 years of follow-up, but it was not correlated with BMI, age, or baseline peptide concentrations.

CONCLUSION

Measurement of ghrelin, insulin, and leptin before surgery is not useful as predictors of WL or WR at long term after RYGBP.

Bariatric surgery for obesity and metabolic conditions in adults

This review summarizes recent evidence related to the safety, efficacy, and metabolic outcomes of bariatric surgery to guide clinical decision making. Several short term randomized controlled trials have demonstrated the effectiveness of bariatric procedures for inducing weight loss and initial remission of type 2 diabetes. Observational studies have linked bariatric procedures with long term improvements in body weight, type 2 diabetes, survival, cardiovascular events, incident cancer, and quality of life. Perioperative mortality for the average patient is low but varies greatly across subgroups. The incidence of major complications after surgery also varies widely, and emerging data show that some procedures are associated with a greater risk of substance misuse disorders, suicide, and nutritional deficiencies. More research is needed to enable long term outcomes to be compared across various procedures and subpopulations, and to identify those most likely to benefit from surgical intervention. Given uncertainties about the balance between the risks and benefits of bariatric surgery in the long term, the decision to undergo surgery should be based on a high quality shared decision making process.

Bariatric surgery for the treatment of Type 2 diabetes: a step closer?

Our objective in the present article is to comment on the recently published randomized control trials of bariatric surgery versus medical treatment for managing Type 2 diabetes. In particular, we will discuss how these trials impact the evidence base for the addition of bariatric surgery in Type 2 diabetes treatment algorithms.

The role of hormonal factors in weight loss and recidivism after bariatric surgery

Substantial heterogeneity exists in weight loss trajectories amongst patients following bariatric surgery. Hormonal factors are postulated to be amongst the contributors to the variation seen. Several hormones involved in hunger, satiety, and energy balance are affected by bariatric surgery, with the alteration in hormonal milieu varying by procedure. Limited research has been conducted to examine potential hormonal mediators of weight loss failure or recidivism following bariatric surgery. While hormonal factors that influence weight loss success following gastric banding have not been identified, data suggest that hormonal factors may be involved in modulating weight loss success following gastric bypass. There may be hormonal mediators involved in determining the weight trajectory following sleeve gastrectomy, though the extremely limited data currently available prohibits definitive conclusions from being drawn. There is great need for future research studies to explore this knowledge gap, as improving this knowledge base could be of benefit to guide clinicians toward understanding the hormonal contributors to a patient's postoperative weight loss failure or recidivism or perhaps be of value in selecting the most appropriate bariatric procedure based on the preoperative hormone milieu. Integrative interdisciplinary approaches exploring these complex interrelationships could potentially increase the explanatory power of such investigations.

Gastrointestinal hormones and bariatric surgery-induced weight loss

Obesity continues to be a major public health problem in the United States and worldwide. While recent statistics have demonstrated that obesity rates have begun to plateau, more severe classes of obesity are accelerating at a faster pace with important implications in regards to treatment. Bariatric surgery has a profound and durable effect on weight loss, being to date one of the most successful interventions for obesity.

OBJECTIVE

To provide updates to the possible role of gut hormones in post bariatric surgery weight loss and weight loss maintenance.

DESIGN AND METHODS

The current review examines the changes in gastro-intestinal hormones with bariatric surgery and the potential mechanisms by which these changes could result in decreased weight and adiposity.

RESULTS

The mechanism by which bariatric surgery results in body weight changes is incompletely elucidated, but it clearly goes beyond caloric restriction and malabsorption.

CONCLUSION

Changes in gastro-intestinal hormones, including increases in GLP-1, PYY, and oxyntomodulin, decreases in GIP and ghrelin, or the combined action of all these hormones might play a role in induction and long-term maintenance of weight loss.

All bariatric surgeries are not created equal: insights from mechanistic comparisons

Despite considerable scientific progress on the biological systems that regulate energy balance, we have made precious little headway in providing new treatments to curb the obesity epidemic. Diet and exercise are the most popular treatment options for obesity, but rarely are they sufficient to produce long-term weight loss. Bariatric surgery, on the other hand, results in dramatic, sustained weight loss and for this reason has gained increasing popularity as a treatment modality for obesity. At least some surgical approaches also reduce obesity-related comorbidities including type 2 diabetes and hyperlipidemia. This success puts a premium on understanding how these surgeries exert their effects. This review focuses on the growing human and animal model literature addressing the underlying mechanisms. We compare three common procedures: Roux-en-Y Gastric Bypass (RYGB), vertical sleeve gastrectomy (VSG), and adjustable gastric banding (AGB). Although many would group together VSG and AGB as restrictive procedures of the stomach, VSG is more like RYGB than AGB in its effects on a host of endpoints including intake, food choice, glucose regulation, lipids and gut hormone secretion. Our strong belief is that to advance our understanding of these procedures, it is necessary to group bariatric procedures not on the basis of surgical similarity but rather on how they affect key physiological variables. This will allow for greater mechanistic insight into how bariatric surgery works, making it possible to help patients better choose the best possible procedure and to develop new therapeutic strategies that can help a larger portion of the obese population.

Mechanisms responsible for excess weight loss after bariatric surgery

Obesity has increased alarmingly in the United States and is increasing in many countries of the world. Because obesity is an important risk factor for type 2 diabetes and other chronic diseases, it is important to develop approaches to counter the rapid increase in adiposity. One approach is bariatric surgery, the most successful clinical intervention known for treating obesity. Surgery can result in impressive weight loss and improvement of obesity-related comorbidities. Yet the mechanisms responsible for this remarkable effect of surgery remain controversial. It is now clear that caloric restriction, per se, does not explain all the reduction in stored fat mass after surgery. A number of gastrointestinal hormones, including glucagon-like peptide (GLP)-1, peptide YY, oxyntomodulin, GLP-2, glucose-dependent insulinotropic polypeptide, ghrelin, and others, can play roles in energy homeostasis and could be involved in bariatric-surgery-related weight loss and weight loss maintenance. Vagal innervation may play a role. In addition, there may be other yet-uncharacterized factors that could participate. This review discusses the possible roles of these hormonal mechanisms in various types of bariatric surgery to help elucidate some of the potential mechanisms at play in short-term and long-term post-bariatric surgery weight loss. Understanding such mechanisms could lead to new and efficacious means to control or even reduce the epidemic of obesity.

Comparison of comorbidity resolution and improvement between laparoscopic sleeve gastrectomy and laparoscopic adjustable gastric banding

BACKGROUND

This study aimed to compare the rates for resolution and improvement of common comorbidities between laparoscopic sleeve gastrectomy (LSG) and laparoscopic adjustable gastric banding. The comorbid conditions included were type 2 diabetes mellitus (DM), hypertension (HTN), hyperlipidemias (LPD), degenerative joint disease (DJD), gastroesophageal reflux disease (GERD), obstructive sleep apnea (OSA), and asthma.

METHODS

A retrospective chart review of the patients who underwent LSG or laparoscopic adjustable gastric banding at our institution from July 2004 to July 2007 was performed. The resolution of comorbidities was determined via patient-completed questionnaires and objective data.

RESULTS

Of the 123 patients (29 men and 94 women) reviewed, 49 had undergone LSG, and 74 had undergone laparoscopic adjustable gastric banding. The mean preoperative body mass index (BMI) was 52 kg/m(2) for the LSG patients and 44 kg/m(2) for the laparoscopic adjustable gastric banding patients. The overall percentages of excess weight loss (%EWL) were respectively 50.6 and 40.3% (P = 0.03) during mean follow-up periods of 15 and 17 months. There was a greater resolution or improvement of DM after LSG (100% vs 46%), HTN (78% vs 48%), and LPD (87% vs. 50%) than after laparoscopic adjustable gastric banding. Other comorbidities resolved or improved at a similar rate.

CONCLUSIONS

Although both LSG and laparoscopic adjustable gastric banding resulted in postoperative improvement or resolution of comorbidities associated with obesity, LSG statistically showed a significantly higher rate of resolution or improvement of DM, HTN, and LPD. There was no significant difference between the groups for DJD, GERD, OSA, or asthma.

The effect of laparoscopic gastric banding surgery on plasma levels of appetite-control, insulinotropic, and digestive hormones

BACKGROUND

We hypothesized that laparoscopic adjustable gastric banding (LAGB) reduces weight and modulates ghrelin production, but largely spares gastrointestinal endocrine function. To examine this hypothesis, we determined plasma concentrations of appetite-control, insulinotropic, and digestive hormones in relation to LAGB.

METHODS

Twenty-four patients undergoing LAGB were prospectively enrolled. Body mass index (BMI) was measured and blood samples obtained at baseline and 6 and 12 months post-surgery. Plasma concentrations of leptin, acylated and total ghrelin, pancreatic polypeptide (PP), insulin, glucose-dependent insulinotropic peptide (GIP), active glucagon-like peptide-1 (GLP-1), gastrin, and pepsinogens I and II were measured using enzyme-linked immunoassays.

RESULTS

Median percent excess weight loss (%EWL) over 12 months was 45.7% with median BMI decreasing from 43.2 at baseline to 33.8 at 12 months post-surgery (p < 0.001). Median leptin levels decreased from 19.7 ng/ml at baseline to 6.9 ng/ml at 12 months post-surgery (p < 0.001). In contrast, plasma levels of acylated and total ghrelin, PP, insulin, GIP, GLP-1, gastrin, and pepsinogen I did not change in relation to surgery (p > 0.05). Pepsinogen II levels were significantly lower 6 months after LAGB but returned to baseline levels by 12 months.

CONCLUSIONS

LAGB yielded substantial %EWL and a proportional decrease in plasma leptin. Our results support the hypothesis that LAGB works in part by suppressing the rise in ghrelin that normally accompanies weight loss. Unchanged concentrations of insulinotropic and digestive hormones suggest that gastrointestinal endocrine function is largely maintained in the long term.

Intragastric injection of botulinum toxin for the treatment of obesity. Where are we?

Obesity has reached epidemic proportions particularly in western countries. Most non-surgical treatments of this condition are disappointing. Since 2005, several studies evaluating the effect of Botulinum Toxin type A (BT-A) in gastric antrum by means of endoscopy for the treatment of obesity have been published. This treatment modality was based on the observation that gastric injection of BT-A in laparatomized rats induced a significant reduction of food intake and body weight. Nowadays, 6 studies have been published yielding conflicting results. Differences in selection of patients, doses of BT-A, method of administration of the toxin and instruments of evaluation of some parameters among these studies may be the cause of divergent results. We discuss herein some important features of these studies pointing out on differences among them. At the same time, based on the knowledge of physiological characteristics of normal and abnormal gastric function related with feeding, we discuss the probable causes of failure observed in these trials. Finally, we give some guidelines concerning the way that future research in this field may follow, not without calling attention to disadvantages of this treatment.

Expression of ghrelin in fundus is increased after gastric banding in morbidly obese patients

BACKGROUND

Ghrelin, a 28 amino-acid acylated orexigenic peptide secreted by the stomach, acts on the hypothalamic arcuate nucleus which stimulates feeding behavior. Serum ghrelin level increases during fasting and decreases after a meal. Serum ghrelin is low in obese patients.Whether ghrelin is implicated in weight loss in obese patients after laparoscopic adjustable gastric banding (LAGB) is still debated. In this study, we assessed serum ghrelin level and gastric fundus expression before and 1 year after LAGB.

METHODS

Gastric fundus expression of ghrelin was assessed by immunohistochemistry using a rabbit anti-human ghrelin antibody simultaneously with serum total ghrelin levels (RIA) in 13 obese patients (2 men and 11 women) after an overnight fast, before LAGB and 1 year after. Immunostaining was "blindly" analyzed by a single pathologist, measuring the density of stained fundic cells near muscularis mucosa.

RESULTS

Mean age of the 13 patients was 41 years, and mean baseline BMI was 46 kg/m2. Pre- and post-LAGB gastric expression of ghrelin was analyzable in 11 patients. It was always identified, mostly with moderate or intense staining. Mean density of stained cells significantly increased 1 year after LAGB: 31/mm2 (21-38) before vs 38/mm2 (27-57) after surgery (P<0.01). This increase did not correlate with changes in BMI, nor did pre- or postoperative gastric expression of ghrelin correlate with the corresponding serum values.

CONCLUSION

We showed for the first time that ghrelin expression assessed by immunohistochemistry was present in the fundus of all 11 obese patients and that it was significantly increased 1 year after LAGB, which would exclude a pathogenetic role of ghrelin in weight loss after LAGB.

The serial changes of ghrelin and leptin levels and their relations to weight loss after laparoscopic minigastric bypass surgery

BACKGROUND

The ghrelin and leptin levels have been reported to be correlated with weight loss after bariatric surgery. However, the serial changes of ghrelin and leptin levels after laparoscopic minigastric bypass surgery (LMGBP) have not been reported yet. Therefore, we aimed to evaluate their serial changes and to analyze their relations to weight reduction after LMGBP.

METHODS

Serial fasting serum leptin and ghrelin concentrations were measured in 68 morbidly obese patients before (M0) and 1 (M1), 3 (M3), 6 (M6), and 12 (M12) months after LMGBP surgery. The correlations between ghrelin, insulin, and leptin concentrations and weight reduction were analyzed.

RESULTS

Leptin levels were significantly reduced at 1, 3, 6, and 12 months after surgery, respectively (vs M0, p < 0.001), whereas the ghrelin concentrations were not significantly changed after surgery. The percent of excess BMI lost (%EBL) 12 months after surgery was negatively correlated with higher preoperative ghrelin concentrations (p = 0.004) and larger preoperative BMI (p = 0.002) in the multivariate analysis.

CONCLUSION

Higher preoperative ghrelin concentrations and larger BMI are predictive of less %EBL at 12 months after LMGBP surgery.

Entero-Endocrine Changes After Gastric Bypass in Diabetic and Nondiabetic Patients: A Preliminary Study

INTRODUCTION

Alterations in entero-endocrine signaling may play a role in improvements in satiety and glucose tolerance after Roux-en-Y gastric bypass (RYGB). We report our findings of gut hormone secretion in a cohort of diabetic and nondiabetic morbidly obese patients.

MATERIALS AND METHODS

Ten morbidly obese subjects who underwent uncomplicated RYGB were studied: 5 were diabetic and 9 were female. Nonfasting plasma levels of glucagon-like peptide-1 (GLP-1), insulin, desacyl ghrelin, active ghrelin, neuropeptide Y (NPY), and gastric inhibitory polypeptide (GIP) were determined preoperatively and 6 months postoperatively.

RESULTS

Mean patient age was 42 +/- 11 years, and the mean preoperative body mass index was 50 +/- 6 kg/m(2). At 6 months mean BMI fell to 33 +/- 5 kg/m(2) (P < 0.0001), and there were no differences between diabetics and nondiabetics with respect to amount of weight loss. In non-diabetics, compared to preoperative levels, there were significant increases in GLP-1 and desacyl-ghrelin in the nondiabetic patients (P = 0.046 and P = 0.016, respectively); no change in plasma insulin, active ghrelin, NPY, or GIP was demonstrated. In contrast, when compared to preoperative levels, there were no significant changes in entero-endocrine hormone levels in the diabetic cohort postoperatively.

CONCLUSIONS

At 6 months postoperation, RYGB significantly alters the hormone levels for GLP-1 and desacyl-ghrelin in morbidly obese nondiabetic patients. No significant change was noted in a matched cohort of diabetic patients. Weight loss was similar in diabetics and nondiabetics, suggesting that GLP-1 and ghrelin are not the only mechanisms producing weight loss after RYGB.