Changes in ghrelin levels following bariatric surgery: review of the literature

Psychopathology, disordered eating, and impulsivity as predictors of weight loss 24 months after metabolic and bariatric surgery

BACKGROUND

The relationship between theoretically relevant psychosocial and behavioral variables and outcomes of metabolic and bariatric surgery remains unclear. Some studies have found that the presence of psychopathology, disordered eating, and impulsivity, either before surgery or during the early postoperative period, is associated with suboptimal postoperative weight loss. Other studies have not found these relationships.

OBJECTIVE

Examine the relationship between psychopathology, disordered eating, impulsivity, and weight loss 24 months postoperatively.

SETTING

Two large, urban university health systems.

METHODS

Participant characteristics were collected using validated interviews, patient-reported outcome measures, and computerized assessment methods. Linear mixed effect models were used to test the association of the variables of interest on percent weight loss (%WL).

RESULTS

Three hundred participants were enrolled at baseline; weight data at 24 months were available for 227 participants; between 181 and 53 individuals completed other outcome measures. The mean %WL was 23.3 ± 9.9% at 24 months. Patients who underwent Roux-en-Y gastric bypass lost more weight than those who underwent sleeve gastrectomy. The presence of subjective binge episodes at baseline was related to a greater %WL at 24 months; there were no other baseline predictors. The presence of eating disorder diagnoses and disordered eating symptoms after surgery were associated with smaller weight losses over 24 months. Current and lifetime psychopathology and impulsivity were unrelated to %WL at 24 months.

CONCLUSION

Disordered eating after bariatric surgery was associated with a smaller %WL at postoperative year 2. Additional monitoring of these symptoms in the early postoperative period is recommended. Psychotherapeutic and/or dietary interventions may promote more optimal weight loss outcomes.

Suboptimal Weight Loss 13 Years After Roux-en-Y Gastric Bypass Is Associated with Blunted Appetite Response

PURPOSE

Bariatric surgery remains the most efficient treatment to achieve a sustained weight loss. However, a large proportion of patients experience suboptimal weight loss (SWL). The exact mechanisms involved remain to be fully elucidated, but the homeostatic appetite control system seems to be involved. The aim of this study was, therefore, to compare the plasma concentration of gastrointestinal hormones, and appetite ratings, between those experiencing SWL and optimal weight loss (OWL) after Roux-en-Y gastric bypass (RYGB).

MATERIALS AND METHODS

Fifty participants from the Bariatric Surgery Observation Study (BAROBS) experiencing either SWL or OWL (< or ≥ 50% of excess weight loss (EWL), respectively) > 13 years post-RYGB were compared to 25 non-surgical controls. Plasma concentrations of acylated ghrelin (AG), total glucagon-like peptide-1 (GLP-1), total peptide YY (PYY), cholecystokinin (CCK), and subjective ratings of hunger, fullness, desire to eat (DTE), and prospective food consumption (PFC) were assessed in the fasting and postprandial (area under the curve (AUC)) states.

RESULTS

Those experiencing OWL presented with higher basal AG and GLP-1 iAUC, and lower AG iAUC compared with SWL and controls. Additionally, both bariatric groups presented with higher PYY and CCK iAUC compared to controls. PFC tAUC was also lower in OWL compared to the SWL group. Total weight loss was positively correlated with GLP-1 tAUC and negatively correlated with fasting and tAUC DTE and PFC tAUC.

CONCLUSIONS

SWL > 13 years post-RYGB is associated with lower basal ghrelin, as well as a weaker satiety response to a meal. Future studies should investigate the causality of these associations.

Mucosal and hormonal adaptations after Roux-en-Y gastric bypass

The aim of this study was to perform a comprehensive literature review regarding the relevant hormonal and histologic changes observed after Roux-en-Y gastric bypass (RYGB). We aimed to describe the relevant hormonal (glucagon-like peptides 1 and 2 [GLP-1 and GLP-2], peptide YY [PYY], oxyntomodulin [OXM], bile acids [BA], cholecystokinin [CCK], ghrelin, glucagon, gastric inhibitory polypeptide [GIP], and amylin) profiles, as well as the histologic (mucosal cellular) adaptations happening after patients undergo RYGB. Our review compiles the current evidence and furthers the understanding of the rationale behind the food intake regulatory adaptations occurring after RYGB surgery. We identify gaps in the literature where the potential for future investigations and therapeutics may lie. We performed a comprehensive database search without language restrictions looking for RYGB bariatric surgery outcomes in patients with pre- and postoperative blood work hormonal profiling and/or gut mucosal biopsies. We gathered the relevant study results and describe them in this review. Where human findings were lacking, we included animal model studies. The amalgamation of physiologic, metabolic, and cellular adaptations following RYGB is yet to be fully characterized. This constitutes a fundamental aspiration for enhancing and individualizing obesity therapy.

Changes in Plasma Ghrelin Levels Following Surgical and Non-Surgical Weight-Loss in Female Rats Predict Alcohol Use

The weight-loss surgery Roux-en Y gastric bypass (RYGB) is a relatively effective, long-term treatment option for patients with morbid obesity. However, accumulating clinical evidence suggests that patients receiving RYGB may be at increased risk of developing alcohol use disorder. This observation has been repeatedly supported by preclinical studies showing rodents increase intake of ethanol (EtOH) after RYGB, and has been further confirmed by human studies. A promising alternative to RYGB is sleeve gastrectomy (SG), which has resulted in decreased EtOH consumption in some rodent studies. The exact mechanism underlying the differential alcohol outcomes after RYGB versus SG has yet to be elucidated. However, the gut hormone ghrelin has emerged as a potential candidate from previous preclinical studies specific to RYGB surgeries and due to its action to stimulate food and alcohol intake and cravings. To directly assess changes in plasma ghrelin levels following weigh loss surgeries in the context of alcohol intake, 24 female rats were separated into three surgical groups receiving RYGB, SG, or Sham surgery followed by caloric restriction to produce adiposity matched controls (Sham-AM). Blood was drawn for fasted and fed plasma ghrelin (acyl and des-acyl) assays at multiple time points: while on a normal diet (ND), after 5-week exposure to a high fat diet (HFD), following surgery, and after a series of two-bottle alcohol choice test with increasing concentrations (2%, 4%, 6%, 8%) of EtOH. Consistent with previous observations, RYGB rats drank more EtOH than SG rats across all concentrations. As expected, fasted ghrelin levels were blunted after HFD feeding, compared to normal diet baseline. After RYGB, fasted ghrelin levels returned to higher levels while remained blunted after SG and Sham-AM. Fed acyl ghrelin levels were significantly increased to above "normal" levels after RYGB, but remain low after SG and Sham-AM. Given that post-RYGB acyl ghrelin levels are raised to a fasted state regardless of actual prandial status, we conclude that RYGB may results in a hormonal state reminiscence of a fasted state with the inability of feeding to inhibit ghrelin production, an effect which could potentially contribute to increased EtOH intake following the surgery. In contrast, following SG, ghrelin levels in rats remain consistent with the fed state regardless of prandial status, potentially explaining lower alcohol intake and lower risk of developing AUD.

Care of the Patient After Metabolic and Bariatric Surgery

Weight loss surgery, also known as metabolic and bariatric surgery (MBS), is an effective weight loss treatment and is associated with reduced mortality and improvements in obesity-related health conditions and quality of life. Postsurgical anatomical and physiologic changes include decreased absorption of micronutrients and alterations in gut-brain hormonal regulation that affect many aspects of health. Patients require ongoing monitoring of their physical and mental health for lasting success. Internists, particularly primary care clinicians, are in an ideal position to monitor for nonserious complications in the short and long term, adjust management of chronic diseases accordingly, and monitor for mental health changes. This article reviews key issues that internists should be aware of for supporting patients' health in the short and long term after MBS.

Maternal cardiovascular adaptation to pregnancy in women with previous bariatric surgery

BACKGROUND

Obesity in pregnancy is associated with substantial risks, notably hypertensive disorders. Bariatric surgery achieves sustained weight loss and has several cardiovascular benefits, including positive effects on blood pressure, cardiac geometry, and both systolic and diastolic function. Pregnancy following bariatric surgery is also associated with improved outcomes, including a reduced risk of hypertensive disorders. The underlying mechanisms, however, remain uncertain. Maternal cardiovascular adaptation plays a vital role in maintaining a healthy pregnancy, and maladaptation has been associated with adverse pregnancy outcomes. However, to date, the maternal cardiovascular adaptation to pregnancy after bariatric surgery has not been investigated.

OBJECTIVE

To investigate the maternal cardiovascular adaptation to pregnancy in women with previous bariatric surgery compared with women with a similar early-pregnancy body mass index, age, and race but no history of weight loss surgery.

STUDY DESIGN

This was a prospective, observational, longitudinal study including pregnant women with (n=41) and without (n=41) a history of bariatric surgery. The participants were seen at 3 time points; at 12 to 14, 20 to 24, and 30 to 32 weeks of pregnancy. At each visit, the blood pressure was measured and the maternal cardiovascular system was assessed using transthoracic echocardiography. Two-dimensional speckle tracking was performed to assess the global longitudinal and circumferential strain on a subset of patients (15 in each group). Offline analysis was performed according to the European and American echocardiography guidelines. Multilevel linear mixed-effect models were used for all the comparisons.

RESULTS

Compared with the no-surgery group, women with previous bariatric surgery, had lower systolic and diastolic blood pressure, heart rate, and cardiac output across all the trimesters (P<.01 for all comparisons), with an evidence of more favorable diastolic indices, including a higher E-wave/A-wave ratio across the mitral valve (P<.001), higher mitral velocity at the lateral and medial annulus (E') (P=.01 and P=.03, respectively), and a lower left atrial volume (P<.05). Furthermore, women with previous bariatric surgery demonstrated lower global longitudinal (P<.01) and circumferential strain (P=.02), which is suggestive of better systolic function.

CONCLUSION

Our findings indicate better cardiovascular adaptation to pregnancy in women with previous bariatric surgery than in pregnant women of a similar early-pregnancy body mass index but no history of surgery.

Bariatric surgery and skeletal health: A narrative review and position statement for management by the European Calcified Tissue Society (ECTS)

CONTEXT

Numerous studies have demonstrated detrimental skeletal consequences following bariatric surgery.

METHODS

A working group of the European Calcified Tissue Society (ECTS) performed an updated review of existing literature on changes of bone turnover markers (BTMs), bone mineral density (BMD), and fracture risk following bariatric surgery and provided advice on management based on expert opinion.

LITERATURE REVIEW

Based on observational studies, bariatric surgery is associated with a 21-44% higher risk of all fractures. Fracture risk is time-dependent and increases approximately 3 years after bariatric surgery. The bariatric procedures that have a malabsorptive component (including Roux-en-Y Gastric bypass (RYGB) and biliopancreatic diversion (BPD)) have clearly been associated with the highest risk of fracture. The extent of high-turnover bone loss suggests a severe skeletal insult. This is associated with diminished bone strength and compromised microarchitecture. RYGB was the most performed bariatric procedure worldwide until very recently, when sleeve gastrectomy (SG) became more prominent. There is growing evidence that RYGB is associated with greater reduction in BMD, greater increase in BTMs, and higher risk of fractures compared with SG but RCTs on optimal management are still lacking.

EXPERT OPINION

In all patients, it is mandatory to treat vitamin D deficiency, to achieve adequate daily calcium and protein intake and to promote physical activity before and following bariatric surgery. In post-menopausal women and men older than 50 years, osteoporosis treatment would be reasonable in the presence of any of the following criteria: i) history of recent fragility fracture after 40 years of age, ii) BMD T-score ≤ -2 at hip or spine, iii) FRAX score with femoral neck BMD exceeding 20% for the 10-year major osteoporotic fracture probability or exceeding 3% for hip fracture. Zoledronate as first choice should be preferred due to intolerance of oral formulations and malabsorption. Zoledronate should be used with caution due to hypocemia risk. It is recommended to ensure adequate 25-OH vitamin D level and calcium supplementation before administering zoledronate.

CONCLUSIONS

The bariatric procedures that have a malabsorptive component have been associated with the highest turnover bone loss and risk of fracture. There is a knowledge gap on osteoporosis treatment in patients undergoing bariatric surgery. More research is necessary to direct and support guidelines.

MECHANISMS IN ENDOCRINOLOGY: The gut-brain axis: regulating energy balance independent of food intake

Obesity is a global pandemic with a large health and economic burden worldwide. Bodyweight is regulated by the ability of the CNS, and especially the hypothalamus, to orchestrate the function of peripheral organs that play a key role in metabolism. Gut hormones play a fundamental role in the regulation of energy balance, as they modulate not only feeding behavior but also energy expenditure and nutrient partitioning. This review examines the recent discoveries about hormones produced in the stomach and gut, which have been reported to regulate food intake and energy expenditure in preclinical models. Some of these hormones act on the hypothalamus to modulate thermogenesis and adiposity in a food intake-independent fashion. Finally, the association of these gut hormones to eating, energy expenditure, and weight loss after bariatric surgery in humans is discussed.

Randomized trial of weight loss on circulating ghrelin levels among breast cancer survivors

Obesity among breast cancer survivors is associated with increased risk for recurrence and mortality. The hormone ghrelin plays a role in initiating appetite and thus regulating body weight. This study aims to determine the effect of a lifestyle intervention on ghrelin levels in breast cancer survivors with a body mass index (BMI) ≥ 25 kg/m2. The Lifestyle, Exercise, and Nutrition (LEAN) study was a 6-month randomized trial, examining the effectiveness of a weight loss intervention versus usual care in 151 breast cancer survivors with BMI ≥ 25 kg/m2. Ghrelin was measured in fasting baseline and 6-month blood samples. Baseline associations between ghrelin, body composition, and blood biomarkers were examined. Six-month change in ghrelin was compared between study arms. Ghrelin measurements were available for 149 women. At baseline, ghrelin was correlated with age (r = 0.28, p < 0.001) and inversely correlated with weight (r = -0.18, p = 0.03), lean body mass (r = -0.18, p = 0.02), and leptin (r = -0.18, p = 0.03). Over 6 months, ghrelin increased by 144 pg/mL (7.2%) in the intervention and decreased by 466 pg/mL (32.5%) in the usual care (p = 0.07). Among all women, greater weight loss was associated with an increase in ghrelin (p = 0.01). These findings indicate that weight loss, achieved through a lifestyle intervention, is associated with higher ghrelin levels in breast cancer survivors which may be informative for developing sustainable weight loss programming for this population. Future research should investigate the long term impacts of lifestyle interventions on ghrelin levels in the context of weight maintenance and weight regain.

From Entero-Endocrine Cell Biology to Surgical Interventional Therapies for Type 2 Diabetes

The physiological roles of the enteroendocrine system in relation to energy and glucose homeostasis regulation have been extensively studied in the past few decades. Considerable advances were made that enabled to disclose the potential use of gastro-intestinal (GI) hormones to target obesity and type 2 diabetes (T2D). The recognition of the clinical relevance of these discoveries has led the pharmaceutical industry to design several hormone analogues to either to mitigate physiological defects or target pharmacologically T2D.Amongst several advances, a major breakthrough in the field was the unexpected observation that enteroendocrine system modulation to T2D target could be achieved by surgically induced anatomical rearrangement of the GI tract. These findings resulted from the widespread use of bariatric surgery procedures for obesity treatment, which despite initially devised to induce weight loss by limiting the systemic availably of nutrients, are now well recognized to influence GI hormone dynamics in a manner that is highly dependent on the type of anatomical rearrangement produced.This chapter will focus on enteroendocrine system related mechanisms leading to improved glycemic control in T2D after bariatric surgery interventions.

Dipeptidyl peptidase-4 activity, lipopolysaccharide, C-reactive protein, glucose metabolism, and gut peptides 3 months after bariatric surgery

BACKGROUND

Bariatric surgery induces weight loss, but changes in glucose metabolism, gut peptides, and inflammatory biomarkers still have conflicting results.

SETTINGS

University hospital.

OBJECTIVES

We investigated glucose metabolism, gut hormones, and inflammatory profile after bariatric surgery and medical treatment.

METHODS

Forty patients with obesity were recruited and were subjected to Roux-en-Y gastric bypass (n = 15; Bariatric Surgery Group - BSG) or received medical care (n = 20; MG). Sleeve gastrectomy was performed in five patients who were excluded from analysis. Glucose, insulin, homeostatic model for the assessment of insulin resistance (HOMA-IR), glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic peptide (GIP), glucagon, ghrelin, dipeptidyl peptidase-4 (DPP-4) activity, circulating lipopolysaccharide (LPS), LPS-binding protein (LPB) and high-sensitivity C-reactive protein (hs-CRP) were evaluated before and three months after each treatment. Except for HOMA-IR, hs-CRP, and LBP, all variables were assessed at fasting and 30- and 60-minutes after a standard meal.

RESULTS

After 3 months, both groups lost weight. However, BSG had a more extensive reduction than MG (respectively, 17.6% vs. 4.25%; P < 0.01). Except for LPS levels, higher on BSG than MG (1.38 ± 0.96 vs. 0.83 ± 0.60 EU/ml, P < 0.01), groups were similar before treatment. In respect to metabolic/hormonal changes, the BSG showed higher glucose, insulin, GLP-1, and GIP levels at 30-min and also GLP-1 at 30- and 60-minutes. DPP-4 activity, HOMA-IR, and fasting LBP did not change. LPS levels at 60-minutes decreased after surgery in the BSG. hs-CRP decreased on BSG compared to MG.

CONCLUSIONS

Bariatric surgery resulted in more extensive effects on glucose metabolism, gut hormones, and inflammation.

The altered enteroendocrine reportoire following roux-en-Y-gastric bypass as an effector of weight loss and improved glycaemic control

The alarming rise in obesity and relative lack of pharmacotherapies to treat, what is becoming a global epidemic, has necessitated that an increasing number of bariatric procedures be performed. Several surgical techniques have been developed during the last 50 years and the advent of laparoscopic surgery has increased the safety and efficacy of these procedures. Bariatric surgery is by a substantial margin, the most efficacious means of achieving sustained weight loss maintenance in patients with obesity. Roux-en-Y gastric bypass surgery (RYGB) elicits the most favourable metabolic outcomes with attendant benefits for type 2 diabetes and, cardiovascular disease as well as endocrine disorders and cancers in females. RYGB is the most extensively studied bariatric procedure regarding mechanism of action. In this review we catalogue the multiple alterations in secretion of gut hormones (ghrelin, obestatin, cholecystokinin, GLP-1, PYY, GIP, oxyntomodulin, glicentin and GLP-2) occurring after RYGB and summarise evidence indicating that these changes play a role in the reduction of food intake and improvements in glucose homeostasis.

Revisiting the Ghrelin Changes Following Bariatric and Metabolic Surgery

Since the description of ghrelin in 1999, several studies have dug into the effects of this hormone and its relationship with bariatric surgery. While some aspects are still unresolved, a clear connection between ghrelin and the changes after metabolic surgery have been established. Besides weight loss, a significant amelioration in obesity-related comorbidities following surgery has also been reported. These changes in patients occur in the early postoperative period, before the weight loss appears, so that amelioration may be mainly due to hormonal changes. The purpose of this review is to go through the current body of knowledge of ghrelin's physiology, as well as to update and clarify the changes that take place in ghrelin concentrations following bariatric/metabolic surgery together with their potential consolidation to outcomes.

Increases in PYY and uncoupling of bone turnover are associated with loss of bone mass after gastric bypass surgery

CONTEXT

The gut hormones peptide YY (PYY) and ghrelin mediate in part the metabolic benefits of Roux-en-Y gastric bypass (RYGB) surgery. However, preclinical data suggest these hormones also affect the skeleton and could contribute to postoperative bone loss.

OBJECTIVE

We investigated whether changes in fasting serum total PYY and ghrelin were associated with bone turnover marker levels and loss of bone mineral density (BMD) after RYGB.

DESIGN, SETTING, PARTICIPANTS

Prospective cohort of adults undergoing RYGB (n=44) at San Francisco academic hospitals.

MAIN OUTCOME MEASURES

We analyzed 6-month changes in PYY, ghrelin, bone turnover markers, and BMD by dual-energy x-ray absorptiometry (DXA) and quantitative computed tomography (QCT). We calculated the uncoupling index (UI), reflecting the relative balance of bone resorption and formation.

RESULTS

Postoperatively, there was a trend for an increase in PYY (+25pg/mL, p=0.07) and a significant increase in ghrelin (+192pg/mL, p<0.01). PYY changes negatively correlated with changes in spine BMD by QCT (r=-0.36, p=0.02) and bone formation marker P1NP (r=-0.30, p=0.05). Relationships were significant after adjustments for age, sex, and weight loss. No consistent relationships were found between ghrelin and skeletal outcomes. Mean 6-month UI was -3.3; UI correlated with spine BMD loss by QCT (r=0.40, p=0.01).

CONCLUSIONS

Postoperative PYY increases were associated with attenuated increases in P1NP and greater declines in spine BMD by QCT. Uncoupling of bone turnover correlated with BMD loss. These findings suggest a role for PYY in loss of bone mass after RYGB and highlight the relationship between intestinal and skeletal metabolism.

Fasting ghrelin levels after gastric bypass and vertical sleeve gastrectomy: An analytic cohort study

BACKGROUND AND OBJECTIVE

Neuronal populations involved in the regulation of food intake, particularly the orexigenic (appetite-stimulating) hormone ghrelin, are found in the hypothalamus. Changes in plasma ghrelin levels have been observed following different bariatric surgery procedures, but the results from different studies are contradictory. Much remains unknown regarding the role of ghrelin in the weight loss process following bariatric surgery. Our objective was to describe the behaviour of fasting ghrelin levels, comparing the changes occurring between 2 different surgical techniques (gastric bypass versus vertical sleeve gastrectomy) and their correlation with weight loss.

PATIENTS AND METHOD

A prospective, observational, analytic cohort study of 54 patients (27 for each surgical technique) with a 12-month follow-up period. We analysed demographic data, anthropometric data, comorbidities, weight loss and evolution of fasting ghrelin.

RESULTS

The behaviour of acylated ghrelin was similar with the 2 surgical techniques, with no significant differences between gastric bypass and vertical sleeve gastrectomy. With both procedures, there was an increase in acylated ghrelin on day 5 and a subsequent decrease, and levels then gradually increased to reach values at 12 months that were higher than those reported preoperatively. This increase in ghrelin levels did not affect weight loss, since one year post-surgery, 30% weight loss was achieved with both types of surgery.

CONCLUSIONS

We observed an increase in fasting acylated ghrelin levels at one year of follow-up with both surgical techniques, with 30% weight loss.

Z-505, an Oral Ghrelin Receptor Agonist, Attenuates Anorexia After Total Gastrectomy in Rats

BACKGROUND

Anorexia is a serious problem in patients with gastric cancer who have undergone gastrectomy. Ghrelin, an orexigenic hormone primarily secreted from the stomach, has been proposed to prevent anorexia. Significant reduction in plasma ghrelin levels after gastrectomy may contribute to lack of appetite and weight loss. In this study, we investigated the effects of Z-505, a ghrelin receptor agonist, on anorexia after total gastrectomy (TG) in a rat model.

METHODS AND MATERIALS

Male Sprague-Dawley rats were used to establish a TG model, and then sham-operated (control) and TG rats were randomly assigned to four subgroups receiving administration of Z-505 (100 mg/kg, p.o., once daily) or vehicle for 14 d from day 14 to day 27 after TG. The food intake, body weight, and fat weight were evaluated during the test period. Moreover, the neuronal activity in the hypothalamus was evaluated on day 21 to investigate the mechanism of action of Z-505.

RESULTS

In TG rats, Z-505 significantly improved the decrease in cumulative food intake induced by the surgery over 14 d (TG + vehicle; 213.8 ± 15.3 g, n = 12 versus TG + Z-505; 258.2 ± 13.1 g, n = 14, P < 0.05). Z-505 also significantly increased fat weight and had a milder effect on body weight over 14 d. In addition, Z-505 significantly increased the number of c-Fos-positive cells in the hypothalamic arcuate nucleus (TG + vehicle; 17.8 ± 2.0, n = 12 versus TG + Z-505; 72.2 ± 11.8, n = 12, P < 0.001).

CONCLUSIONS

Z-505 may be a useful therapeutic treatment for anorexia after TG.

Metabolic Surgery and Diabesity: a Systematic Review

Bariatric surgery is used to induce weight loss (baros = weight). Evidence has shown that bariatric surgery improves the comorbid conditions associated with obesity such as hypertension, hyperlipidemia, and type 2 diabetes mellitus T2DM. Hence, shifting towards using metabolic surgery instead of bariatric surgery is currently more appropriate in certain subset of patients. Endocrine changes resulting from operative manipulation of the gastrointestinal tract after metabolic surgery translate into metabolic benefits with respect to the comorbid conditions. Other changes include bacterial flora rearrangement, bile acids secretion, and adipose tissue effect. The aim of this systematic review is to examine clinical trials regarding long-term effects of bariatric and metabolic surgery on patients with T2DM and to evaluate the potential mechanisms leading to the improvement in the glycaemic control.

Sleeve Gastrectomy and Roux-En-Y Gastric Bypass Lead to Comparable Changes in Body Composition in a Multiethnic Asian Population

BACKGROUND

Changes in body composition after bariatric surgery such as a sustained loss of body fat are often associated with an inevitable loss of fat free mass. This can contribute to an undesirable disturbance in resting metabolic rate and weight maintenance. Our aim was to study changes in body composition in a multiethnic Asian cohort following bariatric surgery and to identify differences between laparoscopic sleeve gastrectomy and laparoscopic Roux-en-Y gastric bypass.

METHODS

A retrospective review of prospectively collected data on 295 patients who underwent either laparoscopic sleeve gastrectomy (256 patients) or laparoscopic Roux-en-Y gastric bypass (39 patients) was performed. Body composition variables were measured with the analyzer, GAIA 359 PLUS, which included the parameters; total body weight, body mass index, excess weight, basal metabolic rate, fat-free mass, fat mass, and total body water.

RESULTS

There were no statistical differences in gender, ethnicity, age, weight, height, and body mass index between laparoscopic sleeve gastrectomy and Roux-en-Y gastric bypass. At each time point (6, 12, 24, and 36 months) post-operation, there was no significant differences in % total body weight loss, basal metabolic rate, fat mass, fat percentage, and total body water between sleeve gastrectomy and bypass patients. There was significant difference (p < 0.05) in fat free mass only at 3 years post-operation, with sleeve gastrectomy patients having 9.79 kg less fat-free mass than bypass patients. However, after multivariate analysis, we found no statistically significant differences.

CONCLUSION

Sleeve gastrectomy and gastric bypass seemed to give similar changes to body composition.

Serum biomarkers of inflammation and adiposity in the LABS cohort: associations with metabolic disease and surgical outcomes

BACKGROUND

The utility of serum biomarkers related to inflammation and adiposity as predictors of metabolic disease prevalence and outcomes after bariatric surgery are not well-defined.

METHODS

Associations between pre- and post-operative serum levels of four biomarkers (C-reactive protein (CRP), cystatin C (CC), leptin, and ghrelin) with baseline measures of adiposity and metabolic disease prevalence (asthma, diabetes, sleep apnea), and weight loss and metabolic disease remission after bariatric surgery were studied in the Longitudinal Assessment of Bariatric Surgery (LABS) cohort.

RESULTS

Baseline CRP levels were positively associated with the odds of asthma but not diabetes or sleep apnea; baseline CC levels were positively associated with asthma, diabetes, and sleep apnea; baseline leptin levels were positively associated with asthma and negatively associated with diabetes and sleep apnea; baseline ghrelin levels were negatively associated with diabetes and sleep apnea. Increased weight loss was associated with increased baseline levels of leptin and CRP and decreased baseline levels of CC. Remission of diabetes and asthma was not associated with baseline levels of any biomarker. A higher likelihood of asthma remission was associated with a greater decrease in leptin levels, and a higher likelihood of diabetes remission was predicted by a lesser decrease in CC. Bariatric surgery was associated with decreased post-operative CC, CRP, and leptin levels, and increased post-operative ghrelin levels.

CONCLUSION

This is the largest study to date of serum biomarkers of inflammation and adiposity in a bariatric surgery cohort. Biomarker levels correlate with metabolic disease prevalence prior to bariatric surgery, and with weight loss but not metabolic disease remission after surgery. Bariatric surgery regulates serum biomarker levels in a manner consistent with anti-inflammatory and compensatory orexigenic effects. These data contribute to our understanding of the mechanisms underlying the biologic effects of bariatric surgery.

Gut adaptation after metabolic surgery and its influences on the brain, liver and cancer

Metabolic surgery is the best treatment for long-term weight loss maintenance and comorbidity control. Metabolic operations were originally intended to change anatomy to alter behaviour, but we now understand that the anatomical changes can modulate physiology to change behaviour. They are no longer considered only mechanically restrictive and/or malabsorptive procedures; rather, they are considered metabolic procedures involving complex physiological changes, whereby gut adaptation influences signalling pathways in several other organs, including the liver and the brain, regulating hunger, satiation, satiety, body weight, glucose metabolism and immune functions. The integrative physiology of gut adaptation after these operations consists of a complex mechanistic web of communication between gut hormones, bile acids, gut microbiota, the brain and both enteric and central nervous systems. The understanding of nutrient sensing via enteroendocrine cells, the enteric nervous system, hypothalamic peptides and adipose tissue and of the role of inflammation has advanced our knowledge of this integrative physiology. In this Review, we focus on the adaptation of gut physiology to the anatomical alterations from Roux-en-Y gastric bypass and vertical sleeve gastrectomy and the influence of these procedures on food intake, weight loss, nonalcoholic fatty liver disease (NAFLD) and cancer. We also aim to demonstrate the underlying mechanisms that could explain how metabolic surgery could be used as a therapeutic option in NAFLD and certain obesity-related cancers.

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.

Metabolic Effects of Bariatric Surgery

BACKGROUND

Obesity can be defined as a chronic subcortical brain disease, as there is an important neurophysiological component to its etiology based on changes in the functioning of those areas of the brain controlling food intake and reward. Extensive metabolic changes accompany bariatric surgery-based treatment of obesity. Consequently, the term “metabolic” surgery is being increasingly adopted in relation to the beneficial effects these procedures have on chronic diseases like type 2 diabetes.

CONTENT

In the present review, we focus on the key biochemical and physiological changes induced by metabolic surgery and highlight the beneficial effects accrued systemically with the use of an organ-based approach. Understanding the impact on and interactions between the gut, brain, adipose tissue, liver, muscle, pancreas, and kidney is key to understanding the sum of the metabolic effects of these operations.

SUMMARY

Further mechanistic studies are essential to assess the true potential of metabolic surgery to treat metabolic comorbidities of obesity beyond type 2 diabetes. Approaches that may mitigate the metabolic side effects of surgery also require attention. Understanding the positive impact of metabolic surgery on metabolic health may result in a wider acceptance of this intervention as treatment for metabolic, comorbid conditions.

Effect of Bariatric Surgery-Induced Weight Loss on Platelet Count and Mean Platelet Volume: a 12-Month Follow-Up Study

BACKGROUND

Abdominal obesity is strongly correlated with cardiovascular risk and associated with platelet hyperactivity. This hyperactivity is associated with an increase in mean platelet volume (MPV). Few data are available about changes in platelet counts and MPV in obese patients after bariatric surgery (BS). The purpose of this study was to describe quantitative and qualitative changes in the platelet lineage after BS.

METHODS

One hundred twenty-eight consecutive patients were included. The mean age was 43 ± 12 years, 77 % of patients were female, and the mean preoperative BMI was 44 ± 6 kg/m². Ninety patients (71 %) had a Roux-en-Y gastric bypass (RYGBP), and 38 (29 %) had a sleeve gastrectomy (SG). Patients were evaluated preoperatively, and postoperative follow-up was performed at 3, 6, and 12 months. The postoperative evaluation included blood samples for full blood count (FBC), including measure of mean platelet volume (MPV).

RESULTS

At the 12-month follow-up, the reduction in preoperative weight was 29 ± 9 %. We showed a significant decrease in platelet count (245 ± 62 vs. 234 ± 54 G/L; p = 0.0015) found in parallel with a non-significant decrease in MPV (9.27 ± 1.1 vs. 9.22 ± 1.05; p = 0.34). With regard to the intervention type, SG caused a more significant decrease in platelet count than RYGBP (p = 0.02). There was no significant difference in MPV variations between the two groups (p = 0.08).

CONCLUSIONS

Our results suggest that BS has a positive impact on platelet metabolism, possibly mediated by weight loss. These data need to be confirmed to understand the multifactorial benefits of BS on cardiovascular risk in obese patients.

Bariatric Surgery: A Perspective for Primary Care

IN BRIEF Bariatric surgery is the most efficacious treatment for obesity, type 2 diabetes, and other obesity-related comorbidities. In this article, the authors review the current indications for bariatric surgery and discuss the most commonly performed procedures. They analyze medical outcomes of bariatric procedures by reviewing key prospective trials and discuss changes in physiology after these procedures. They conclude by discussing long-term management of bariatric patients by reviewing current guidelines for nutritional support and listing common complications related to these procedures.

Metabolic responses to exogenous ghrelin in obesity and early after Roux-en-Y gastric bypass in humans

AIMS

Ghrelin is a gastric-derived hormone that stimulates growth hormone (GH) secretion and has a multi-faceted role in the regulation of energy homeostasis, including glucose metabolism. Circulating ghrelin concentrations are modulated in response to nutritional status, but responses to ghrelin in altered metabolic states are poorly understood. We investigated the metabolic effects of ghrelin in obesity and early after Roux-en-Y gastric bypass (RYGB).

MATERIALS AND METHODS

We assessed central and peripheral metabolic responses to acyl ghrelin infusion (1 pmol kg-1  min-1 ) in healthy, lean subjects (n = 9) and non-diabetic, obese subjects (n = 9) before and 2 weeks after RYGB. Central responses were assessed by GH and pancreatic polypeptide (surrogate for vagal activity) secretion. Peripheral responses were assessed by hepatic and skeletal muscle insulin sensitivity during a hyperinsulinaemic-euglycaemic clamp.

RESULTS

Ghrelin-stimulated GH secretion was attenuated in obese subjects, but was restored by RYGB to a response similar to that of lean subjects. The heightened pancreatic polypeptide response to ghrelin infusion in the obese was attenuated after RYGB. Hepatic glucose production and hepatic insulin sensitivity were not altered by ghrelin infusion in RYGB subjects. Skeletal muscle insulin sensitivity was impaired to a similar degree in lean, obese and post-RYGB individuals in response to ghrelin infusion.

CONCLUSIONS

These data suggest that obesity is characterized by abnormal central, but not peripheral, responsiveness to ghrelin that can be restored early after RYGB before significant weight loss. Further work is necessary to fully elucidate the role of ghrelin in the metabolic changes that occur in obesity and following RYGB.

A new proposed mechanism of action for gastric bypass surgery: Air hypothesis

Roux-en-Y gastric bypass (RYGB) surgery is one of the most effective treatments for obesity and type II diabetes. RYGB was originally believed to work by mechanically restricting caloric intake or causing macronutrient malabsorption. However, such mechanical effects play no role in the remarkable efficacy of gastric bypass. Instead, mounting evidence shows that altered neuroendocrine signaling is responsible for the weight reducing effects of RYGB. The exact mechanism of this surgical response is still a mystery. Here, we propose that RYGB leads to weight loss primarily by inducing a functional shift in the gut microbiome, manifested by a relative expansion of aerobic bacteria numbers in the colon. We point to compelling evidence that gastric bypass changes the function of the microbiome by disrupting intestinal gas homeostasis, causing excessive transit of swallowed air (oxygen) into the colon.

Obesity Impairs the Action of the Neuroendocrine Ghrelin System

Ghrelin is a metabolic hormone that promotes energy conservation by regulating appetite and energy expenditure. Although some studies suggest that antagonizing ghrelin function attenuates body weight gain and glucose intolerance on a high calorie diet, there is little information about the metabolic actions of ghrelin in the obese state. In this review, we discuss the novel concept of obesity-induced central ghrelin resistance in neural circuits regulating behavior, and impaired ghrelin secretion from the stomach. Interestingly, weight loss restores ghrelin secretion and function, and we hypothesize that ghrelin resistance is a mechanism designed to protect a higher body weight set-point established during times of food availability, to maximize energy reserves during a time of food scarcity.

Most common robotic bariatric procedures: review and technical aspects

Since its appear in the year 1997, when Drs. Cadiere and Himpens did the first robotic cholecystectomy in Brussels, not long after the first cholecystectomy, they performed the first robotic bariatric procedure. It is believed that robotically-assisted surgery’s most notable contributions are reflected in its ability to extend the benefits of minimally invasive surgery to procedures not routinely performed using minimal access techniques. We describe the 3 most common bariatric procedures done by robot. The main advantages of the robotic system applied to the gastric bypass appear to be better control of stoma size, avoidance of stapler costs, elimination of the potential for oropharyngeal and esophageal trauma, and a potential decrease in wound infection. While in the sleeve gastrectomy and adjustable gastric banding its utility is more debatable, giving a bigger advantage during surgery on patients with a very large BMI or revisional cases.

Body mass index and ghrelin levels after laparoscopic Nissen fundoplication

PURPOSE

The study aims to evaluate the changes between body mass index (BMI) and ghrelin levels after laparoscopic Nissen fundoplication (LNF).

METHODS

Twenty-four consecutive patients with gastroesophageal reflux disease who were scheduled for LNF consented to participate in the study. The participants' age, sex, preoperative (phase 0), postoperative 1st week (phase 1) and postoperative 4th week (phase 2) dysphagia scores, plasma ghrelin levels, and BMI were recorded.

RESULTS

Compared to the preoperative level (phase 0), ghrelin was decreased in both phase 1 and phase 2. A strong correlation in the changes in the ghrelin values and BMI between phase 0 and phase 2 was detected. There was a strong, statistically significant difference in the changes in the BMI values between phase 1 and phase 2.

CONCLUSIONS

Total plication of the fundus impairs its ghrelin-secreting functions for up to 4 weeks and is accompanied by weight loss.

Remodeling of the residual gastric mucosa after roux-en-y gastric bypass or vertical sleeve gastrectomy in diet-induced obese rats

Whereas the remodeling of intestinal mucosa after bariatric surgeries has been the matter of numerous studies to our knowledge, very few reported on the remodeling of the residual gastric mucosa. In this study, we analyzed remodeling of gastric mucosa after Roux-en-Y gastric bypass (RYGB) and vertical sleeve gastrectomy (VSG) in rats. Diet-induced obese rats were subjected to RYGB, VSG or sham surgical procedures. All animals were assessed for food intake, body-weight, fasting blood, metabolites and hormones profiling, as well as insulin and glucose tolerance tests before and up to 5 weeks post-surgery. Remodeling of gastric tissues was analyzed by routine histology and immunohistochemistry studies, and qRT-PCR analyses of ghrelin and gastrin mRNA levels. In obese rats with impaired glucose tolerance, VSG and RYGB caused substantial weight loss and rats greatly improved their oral glucose tolerance. The remaining gastric mucosa after VSG and gastric pouch (GP) after RYGB revealed a hyperplasia of the mucous neck cells that displayed a strong immunoreactivity for parietal cell H⁺/K⁺-ATPase. Ghrelin mRNA levels were reduced by 2-fold in remaining fundic mucosa after VSG and 10-fold in GP after RYGB. In the antrum, gastrin mRNA levels were reduced after VSG in line with the reduced number of gastrin positive cells. This study reports novel and important observations dealing with the remaining gastric mucosa after RYGB and VSG. The data demonstrate, for the first time, a hyperplasia of the mucous neck cells, a transit cell population of the stomach bearing differentiating capacities into zymogenic and peptic cells.

Mechanisms underlying weight loss and metabolic improvements in rodent models of bariatric surgery

Obesity is a growing health risk with few successful treatment options and fewer still that target both obesity and obesity-associated comorbidities. Despite ongoing scientific efforts, the most effective treatment option to date was not developed from basic research but by surgeons observing outcomes in the clinic. Bariatric surgery is the most successful treatment for significant weight loss, resolution of type 2 diabetes and the prevention of future weight gain. Recent work with animal models has shed considerable light on the molecular underpinnings of the potent effects of these 'metabolic' surgical procedures. Here we review data from animal models and how these studies have evolved our understanding of the critical signalling systems that mediate the effects of bariatric surgery. These insights could lead to alternative therapies able to accomplish effects similar to bariatric surgery in a less invasive manner.

Endocrine and metabolic complications after bariatric surgery

Bariatric surgery is the most effective therapeutic option for obese patients; however, it carries substantial risks, including procedure-related complications, malabsorption, and hormonal disturbance. Recent years have seen an increase in the bariatric surgeries performed utilizing either an independent or a combination of restrictive and malabsorptive procedures. We review some complications of bariatric procedures more specifically, hypoglycemia and osteoporosis, the recommended preoperative assessment and then regular follow up, and the therapeutic options. Surgeon, internist, and the patient must be aware of the multiple risks of this kind of surgery and the needed assessment and follow up.

Skeletal effects of bariatric surgery: examining bone loss, potential mechanisms and clinical relevance

Bariatric surgery is the most effective therapeutic approach to morbid obesity, resulting in substantial weight loss and improved cardiometabolic profiles; however, a growing body of evidence suggests that bariatric procedures increase both skeletal fragility and the risk of related future fracture secondary to excessive bone loss. Prospective evidence shows that areal bone mineral density (BMD) assessed by dual energy X-ray absorptiometry (DXA) declines by as much as 14% in the proximal femoral regions, including the femoral neck and total hip, 12 months postoperatively. Lumbar spine areal BMD outcomes show greater 12-month postoperative variability across surgical procedures (-8 to +6%) and contrast with no change in volumetric BMD outcomes measured by quantitative computed tomography. Diminished mechanical loading, micronutrient deficiency and malabsorption, along with neurohormonal alterations, offer plausible underlying mechanisms to explain these observed post-bariatric bone changes, but most remain largely unsubstantiated in this population. Importantly, DXA-based skeletal imaging may have limited utility in accurately detecting bone change in people undergoing bariatric surgery; partly because excessive tissue overlying bone increases the variability of areal BMD outcomes. Moreover, a paucity of fracture and osteoporosis incidence data raises questions about whether marked post-bariatric surgery bone loss is clinically relevant or a functional adaptation to skeletal unloading. Future studies that use technology which is able to accurately capture the site-specific volumetric BMD and bone architectural changes that underpin bone strength in people undergoing bariatric surgery, that consider mechanical load, and that better quantify long-term fracture and osteoporosis incidence are necessary to understand the actual skeletal effects of bariatric surgery.

Gastrointestinal metabolic surgery for the treatment of type 2 diabetes mellitus

Medical therapy for type 2 diabetes mellitus is ineffective in the long term due to the progressive nature of the disease, which requires increasing medication doses and polypharmacy. Conversely, bariatric surgery has emerged as a cost-effective strategy for obese diabetic individuals; it has low complication rates and results in durable weight loss, glycemic control and improvements in the quality of life, obesity-related co-morbidity and overall survival. The finding that glucose homeostasis can be achieved with a weight loss-independent mechanism immediately after bariatric surgery, especially gastric bypass, has led to the paradigm of metabolic surgery. However, the primary focus of metabolic surgery is the alteration of the physio-anatomy of the gastrointestinal tract to achieve glycemic control, metabolic control and cardio-metabolic risk reduction. To date, metabolic surgery is still not well defined, as it is used most frequently for less obese patients with poorly controlled diabetes. The mechanism of glycemic control is still incompletely understood. Published research findings on metabolic surgery are promising, but many aspects still need to be defined. This paper examines the proposed mechanism of diabetes remission, the efficacy of different types of metabolic procedures, the durability of glucose control, and the risks and complications associated with this procedure. We propose a tailored approach for the selection of the ideal metabolic procedure for different groups of patients, considering the indications and prognostic factors for diabetes remission.

Outcome analysis of early laparoscopic sleeve gastrectomy experience

BACKGROUND AND OBJECTIVES

Laparoscopic vertical sleeve gastrectomy (LSG) was initially performed as the first stage of biliopancreatic diversion with duodenal switch in the super-obese population. In the past few years, however, LSG has been performed as a definitive procedure because of its promising early and midterm results. In this study we describe our initial experience and outcomes with LSG as a potential independent bariatric operation.

METHODS

A prospectively maintained database including all patients between 2008 and 2011 was reviewed.

RESULTS

A total of 100 initial consecutive patients (69 women and 31 men) were included, with a mean age of 50 years (range, 19 -79 years) and body mass index of 49 kg/m(2) (range, 36.6 -70.3 kg/m(2)). The mean operative time was 106 minutes (range, 58 -212 minutes) with a 2% conversion rate. Thirty-day perioperative complications included port-site hemorrhage (1.0%) and the inability to tolerate oral intake resulting in dehydration (3%). The reoperation rate was 2%, and the mean length of stay was 3.1 days (range, 2-12 days). In one patient with a prolonged hospital stay, an acute cholecystitis developed, and prosthetic heart valve complications developed in another patient. The mean excess body weight loss was 18%, 31.7%, 45%, 52%, 58.4%, and 64% at 1, 3, 6, 9, 12, and 18 months postoperatively, respectively. No deaths occurred in this series.

CONCLUSIONS

Satisfactory outcomes and low complication rates were observed after LSG. Our findings suggest that LSG is safe and effective to serve as a definitive bariatric procedure.

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.

Altered ghrelin secretion in mice in response to diet-induced obesity and Roux-en-Y gastric bypass

The current study examined potential mechanisms for altered circulating ghrelin levels observed in diet-induced obesity (DIO) and following weight loss resulting from Roux-en-Y gastric bypass (RYGB). We hypothesized that circulating ghrelin levels were altered in obesity and after weight loss through changes in ghrelin cell responsiveness to physiological cues. We confirmed lower ghrelin levels in DIO mice and demonstrated elevated ghrelin levels in mice 6 weeks post-RYGB. In both DIO and RYGB settings, these changes in ghrelin levels were associated with altered ghrelin cell responsiveness to two key physiological modulators of ghrelin secretion - glucose and norepinephrine. In DIO mice, increases in ghrelin cell density within both the stomach and duodenum and in somatostatin-immunoreactive D cell density in the duodenum were observed. Our findings provide new insights into the regulation of ghrelin secretion and its relation to circulating ghrelin within the contexts of obesity and weight loss.

The impact of laparoscopic sleeve gastrectomy on plasma ghrelin levels: a systematic review

Within the last decade, several authors have proposed laparoscopic sleeve gastrectomy (LSG) as a potential definitive treatment for morbid obesity. While initially perceived as being a solely restrictive procedure, it is now theorized to have additional hormonal effects (primarily the reduction of circulating levels of plasma ghrelin). However, there is limited supporting evidence for this claim. Therefore, the purpose of our study is to conduct a systematic review of the literature to clarify the effects of LSG on modulation of postoperative ghrelin concentrations. A comprehensive literature search for published or unpublished studies of sleeve gastrectomy (SG) and ghrelin written in English prior to February 2013 was performed using Pubmed, EMBASE, the Cochrane database, and Scopus. Gray literature was also searched through Google. Inclusion criteria for searches were: randomized controlled trials, non-randomized clinical trials, retrospective and prospective cohort studies, or case series. Seven studies were deemed suitable for analysis. The mean patient age was 43 ± 8.8 years and female percentage was 74.4 ± 15.3 %. The mean initial BMI was 46.2 ± 7.8 and mean follow-up time was 9.5 ± 15 months. The mean postoperative BMI was 37.3 ± 5.8 over the same follow-up period. Pooled mean preoperative ghrelin levels were 698.4 ± 312.4 pg/ml and postoperative levels were 414.1 ± 226.3 pg/ml (P < 0.0001). Pooled analysis of ghrelin levels at 3, 6, and 12 months showed a significant reduction in circulating levels. Our systematic review shows that LSG has a significant effect on ghrelin levels, leading to considerable reduction in circulation levels following surgery. Further research and standardization is necessary to clearly establish a causative relationship between LSG and reduction of circulating ghrelin levels.

Histopathologic and immunohistochemical sequelae of bariatric embolization in a porcine model

PURPOSE

To evaluate the histopathologic sequelae of bariatric embolization on the gastric mucosa and to correlate with immunohistochemical evaluation of the gastric fundus, antrum, and duodenum.

MATERIALS AND METHODS

This study was performed on 12 swine stomach and duodenum specimens after necropsy. Of the 12 swine, 6 had previously undergone bariatric embolization of the gastric fundus, and the 6 control swine had undergone a sham procedure with saline. Gross pathologic, histopathologic, and immunohistochemical examinations of the stomach and duodenum were performed. Specifically, mucosal integrity, fibrosis, ghrelin-expressing cells, and gastrin-expressing cells were assessed.

RESULTS

Gross and histopathologic evaluation of treatment animals showed healing or healed mucosal ulcers in 50% of animals, with gastritis in 100% of treatment animals and in five of six control animals. The ghrelin-immunoreactive mean cell density was significantly lower in the gastric fundus in the treated animals compared with control animals (15.3 vs 22.0, P < .01) but similar in the gastric antrum (9.3 vs 14.3, P = .08) and duodenum (8.5 vs 8.6, P = .89). The gastrin-expressing cell density was significantly lower in the antrum of treated animals compared with control animals (82.2 vs 126.4, P = .03). A trend toward increased fibrosis was suggested in the gastric fundus of treated animals compared with controls (P = .07).

CONCLUSIONS

Bariatric embolization resulted in a significant reduction in ghrelin-expressing cells in the gastric fundus without evidence of upregulation of ghrelin-expressing cells in the duodenum. Healing ulcerations in half of treated animals underscores the need for additional refinement of this procedure.

Sub-sleeve gastrectomy achieves good diabetes control without weight loss in a non-obese diabetic rat model

BACKGROUND

Although weight loss has been implicated in anti-diabetic effects, sleeve gastrectomy (SG)-mediated anti-diabetic effects are induced through mechanisms beyond weight loss. Our aim was to investigate whether anti-diabetic effects can be achieved by surgically removing a smaller portion of the stomach instead of SG.

METHODS

Male 11-week-old Goto-Kakizaki rats (N = 50) were randomized into five groups: sub-sleeve gastrectomy (SSG, only the gastric fundus is removed), SG, sham-operated SSG, sham-operated SG, and control. Body weight, food intake, hormone secretion, and glucose metabolism were measured up to 24 weeks after surgery.

RESULTS

The data showed that (i) both SSG and SG surgeries significantly improved glucose homeostasis, with lower ghrelin levels and higher post-prandial glucagon-like peptide 1, peptide YY, and insulin levels; (ii) SG, but not SSG, produced sustained weight loss and significant reduction of food intake; and (iii) SG induced better long-term diabetic improvement than SSG.

CONCLUSIONS

The SSG that only removed the gastric fundus exhibited significant diabetic improvement without weight loss, but did not induce long-term diabetic improvement comparable to that of SG. Our study helps to understand the role of hormones and weight loss in maintaining long-term diabetes improvement after SG.

Type 2 diabetes control in a nonobese rat model using sleeve gastrectomy with duodenal-jejunal bypass (SGDJB)

BACKGROUND

As a new bariatric procedure, sleeve gastrectomy with duodenal-jejunal bypass (SGDJB) needs further assessment. We compared the diabetic control between SGDJB and sleeve gastrectomy (SG) in Goto-Kakizaki (GK) rats, a nonobese rat model of type 2 diabetes. Our aim is firstly to develop a nonobese diabetic rat model for SGDJB and secondly to investigate the feasibility and safety of SGDJB to induce diabetes remission.

METHODS

Fifty 11-week-old male GK rats were divided into five groups: sham-operated SG (SOSG), sham-operated SGDJB (SOSGDJB), control, SG, and SGDJB. Rats were observed for 16 weeks after surgery. The body weight, food intake, glycemic control outcomes, ghrelin, peptide YY (PYY), insulin, glucagon-like peptide 1 (GLP-1), and glucose-dependent insulinotropic peptide were measured.

RESULTS

The operated groups showed lower food intake since 4 weeks postoperation and significant weight loss since 6 weeks postoperation. SGDJB and SG surgeries induced a decreased fasting ghrelin level and increased levels of glucose-stimulated insulin, GLP-1, and PYY secretion at 2 and 16 weeks postoperation. Compared with the SG group, the SGDJB group showed higher glucose-stimulated GLP-1 levels. Both SGDJB and SG groups exhibited significant improvement in oral glucose tolerance and insulin tolerance compared with sham-operated and control groups, but there was no difference between the operated groups.

CONCLUSIONS

This nonobese diabetic rat model may be valuable in studying the effect of SGDJB on diabetic control. SGDJB shows similar improvement of glucose metabolism with SG. Our findings do not provide evidence for the foregut-mediated amelioration in glucose homeostasis.

Quantitative immunohistochemical analysis of duodenal ghrelin cells after sleeve gastrectomy in Wistar rats

PURPOSE

Sleeve gastrectomy (SG) removes substantial part of the gastric mucosa, which produces ghrelin. This reduction is expected to force other organs, such as the duodenum, to compensate by increasing the number of ghrelin-producing cells. The purpose of this study was to evaluate whether this response occurs.

METHODS

Twelve adult male, Wistar rats underwent SG and were reoperated 30 or 60 days after the initial surgery. During the second surgery, a segment of the duodenum was resected to count ghrelin cells using immunohistochemistry. In six animals, SG was not performed, and the duodenal segment served as a control for ghrelin cell counts. The ghrelin cell index (GCI), which is the number of ghrelin cells divided by the number of villi in each segment, was measured and used in statistical analysis by one-way analysis of variance (ANOVA).

RESULTS

There were increases in the absolute numbers of cells 30 and 60 days after SG, but statistical analysis by ANOVA showed no significant difference between the groups.

CONCLUSION

A compensatory increase in the number of duodenal immunopositive ghrelin cells did not occur as a response to sleeve gastrectomy.