Importance of small bowel peptides for the improved glucose metabolism 20 years after jejunoileal bypass for obesity

Role and mechanism(s) of incretin-dependent therapies for treating diabetes mellitus

Diabetes mellitus (DM) is a worldwide ailment which leads to chronic complications like cardiac disorders, renal perturbations, limb amputation and blindness. Type one diabetes (T1DM), Type two diabetes (T2DM), Another types of diabetes, such as genetic errors in function of β-cell and action of insulin, cystic fibrosis, chemical-instigated diabetes or following tissue transplantation), and pregnancy DM (GDM). In response to nutritional ingestion, the gut may release a pancreatic stimulant that affects carbohydrate metabolism. The duodenum produces a 'chemical excitant' that stimulates pancreatic output, and researchers have sought to cure diabetes using gut extract injections, coining the word 'incretin' to describe the phenomena. Incretins include GIP and GLP-1. The 'enteroinsular axis' is the link between pancreas and intestine. Nutrient, neuronal and hormonal impulses from intestine to cells secreting insulin were thought to be part of this axis. In addition, the hormonal component, incretin, must meet two requirements: (1) it secreted by foods, mainly carbohydrates, and (2) it must induce an insulinotropic effect which is glucose-dependent. In this review, we clarify the ability of using incretin-dependent treatments for treating DM.

Plasma glucagon-like peptide-1 responses to ingestion of protein with increasing doses of milk minerals rich in calcium

A high dose of whey protein hydrolysate fed with milk minerals rich in calcium (Capolac®) results in enhanced glucagon-like peptide-1 (GLP-1) concentrations in lean individuals; however, the effect of different calcium doses ingested alongside protein is unknown. The present study assessed the dose response of calcium fed alongside 25 g whey protein hydrolysate on GLP-1 concentrations in individuals with overweight/obesity. Eighteen adults (mean ± sd: 8M/10F, 34 ± 18 years, 28·2 ± 2·9 kgm-2) completed four trials in a randomised, double-blind, crossover design. Participants consumed test solutions consisting of 25 g whey protein hydrolysate (CON), supplemented with 3179 mg (LOW), 6363 mg (MED) or 9547 mg (HIGH) Capolac® on different occasions, separated by at least 48 h. The calcium content of test solutions equated to 65, 892, 1719 and 2547 mg, respectively. Arterialised-venous blood was sampled over 180 min to determine plasma concentrations of GLP-1TOTAL, GLP-17-36amide, insulin, glucose, NEFA, and serum concentrations of calcium and albumin. Ad libitum energy intake was measured at 180 min. Time-averaged incremental AUC (iAUC) for GLP-1TOTAL (pmol·l-1·min-1) did not differ between CON (23 ± 4), LOW (25 ± 6), MED (24 ± 5) and HIGH (24 ± 6). Energy intake (kcal) did not differ between CON (940 ± 387), LOW (884 ± 345), MED (920 ± 334) and HIGH (973 ± 390). Co-ingestion of whey protein hydrolysate with Capolac® does not potentiate GLP-1 release in comparison with whey protein hydrolysate alone. The study was registered at clinical trials (NCT03819972).

Metabolic and cardiovascular outcomes of bariatric surgery

PURPOSE OF REVIEW

Bariatric surgery is an effective therapy for morbid obesity that also improves weight-related metabolic parameters and reduces morbidity and mortality. The purpose of this review is to consolidate our current understanding of metabolic, macrovascular and microvascular benefits of bariatric surgery and to provide an update.

RECENT FINDINGS

Early resolution of insulin resistance and type 2 diabetes mellitus (T2DM) varies by type of bariatric surgery and appears to be mediated by changes in secretion of gut hormones, metabolism of bile acids, expression of glucose transporters and the gut microbiome. Dyslipidaemia, atherosclerosis, microvascular complications of obesity and diabetes, systemic and tissue-level inflammation show evidence of regression and hypertension improves significantly after bariatric surgery.

SUMMARY

Bariatric surgery leads to improvements in obesity-related metabolic comorbidities such as dyslipidaemia, HDL functionality, hypertension, T2DM, insulin resistance and inflammation. It slows the atherosclerotic process and reduces cardiovascular and all-cause mortality. Recent data have demonstrated regression of the microvascular complications of obesity and diabetes including the regeneration of small nerve fibres. The magnitude of change in short-term metabolic effects depends on the surgical procedure whilst longer term effects are related to the amount of sustained excess weight loss.

Cardiac remodeling in obesity and after bariatric and metabolic surgery; is there a role for gastro-intestinal hormones?

Introduction: Obesity is associated with various diseases such as type 2 diabetes, hypertension, obstructive sleep apnea syndrome (OSAS), metabolic syndrome, and cardiovascular diseases. It affects several organ systems, including the pulmonary and cardiac systems. Furthermore, it induces pulmonary and cardiac changes that can result in right and/or left heart failure.Areas covered: In this review, authors provide an overview of obesity and cardiovascular remodeling, the individual actions of the gut hormones (like GLP-1 and PYY), the effects after bariatric/metabolic surgery and its influence on cardiac remodeling. In this review, we focussed and searched for literature in Pubmed and The Cochrane library (from the earliest date until April 2019), regarding cardiac function changes before and after bariatric surgery and literature regarding changes in gastrointestinal hormones.Expert opinion: Regarding the surgical treatment of obesity and metabolic diseases there is recognition of the importance of both weight loss (bariatric surgery) and improvement in metabolic milieu (metabolic surgery). A growing body of evidence further suggests that bariatric surgical procedures [like the Sleeve Gastrectomy (SG), Roux-en Y Gastric Bypass (RYGB), or One Anastomosis Gastric Bypass (OAGB)] have can improve outcomes of patients suffering from a number of cardiovascular diseases, including heart failure.

Glycemic Control after Sleeve Gastrectomy and Roux-En-Y Gastric Bypass in Obese Subjects with Type 2 Diabetes Mellitus

Background

Roux-en-Y gastric bypass (LRYGB) has weight-independent effects on glycemia in obese type 2 diabetic patients, whereas sleeve gastrectomy (LSG) is less well characterized. This study aims to compare early weight-independent and later weight-dependent glycemic effects of LRYGB and LSG.

Methods

Eighteen LRYGB and 15 LSG patients were included in the study. Glucose, insulin, GLP-1, and GIP levels were monitored during a modified 30 g oral glucose tolerance test before surgery and 2 days, 3 weeks, and 12 months after surgery. Patients self-monitored glucose levels 2 weeks before and after surgery.

Results

Postoperative fasting blood glucose decreased similarly in both groups (LRYGB vs. SG; baseline—8.1 ± 0.6 vs. 8.2 ± 0.4 mmol/l, 2 days—7.8 ± 0.5 vs. 7.4 ± 0.3 mmol/l, 3 weeks—6.6 ± 0.4 vs. 6.6 ± 0.3 mmol/l, respectively, P < 0.01 vs. baseline for both groups; 12 months—6.6 ± 0.4 vs. 5.9 ± 0.4, respectively, P < 0.05 for LRYGB and P < 0.001 for LSG vs. baseline, P = ns between the groups at all times). LSG, but not LRYGB, showed increased peak insulin levels 2 days postoperatively (mean ± SEM; LSG + 58 ± 14%, P < 0.01; LRYGB − 8 ± 17%, P = ns). GLP-1 levels increased similarly at 2 days, but were higher in LRYGB at 3 weeks (AUC; 7525 ± 1258 vs. 4779 ± 712 pmol × min, respectively, P < 0.05). GIP levels did not differ. Body mass index (BMI) decreased more after LRYGB than LSG (− 10.1 ± 0.9 vs. − 7.9 ± 0.5 kg/m², respectively, P < 0.05).

Conclusion

LRYGB and LSG show very similar effects on glycemic control, despite lower GLP-1 levels and inferior BMI decrease after LSG.

Electronic supplementary material

The online version of this article (10.1007/s11695-017-3061-3) contains supplementary material, which is available to authorized users.

Peptide-based multi-agonists: a new paradigm in metabolic pharmacology

Obesity and its comorbidities, such as type 2 diabetes, are pressing worldwide health concerns. Available anti-obesity treatments include weight loss pharmacotherapies and bariatric surgery. Whilst surgical interventions typically result in significant and sustained weight loss, available pharmacotherapies are far less effective, typically decreasing body weight by no more than 5-10%. An emerging class of multi-agonist drugs may eventually bridge this gap. This new class of specially tailored drugs hybridizes the amino acid sequences of key metabolic hormones into one single entity with enhanced potency and sustained action. Successful examples of this strategy include multi-agonist drugs targeting the receptors for glucagon-like peptide-1 (GLP-1), glucagon and the glucose-dependent insulinotropic polypeptide (GIP). Due to the simultaneous activity at several metabolically relevant receptors, these multi-agonists offer improved body weight loss and glucose tolerance relative to their constituent monotherapies. Further advancing this concept, chimeras were generated that covalently link nuclear acting hormones such as oestrogen, thyroid hormone (T₃ ) or dexamethasone to peptide hormones such as GLP-1 or glucagon. The benefit of this strategy is to restrict the nuclear hormone action exclusively to cells expressing the peptide hormone receptor, thereby maximizing combinatorial metabolic efficacy of both drug constituents in the target cells whilst preventing the nuclear hormone cargo from entering and acting on cells devoid of the peptide hormone receptor, in which the nuclear hormone might have unwanted effects. Many of these multi-agonists are in preclinical and clinical development and may represent new and effective tools in the fight against obesity and its comorbidities.

Gut-Brain Cross-Talk in Metabolic Control

Because human energy metabolism evolved to favor adiposity over leanness, the availability of palatable, easily attainable, and calorically dense foods has led to unprecedented levels of obesity and its associated metabolic co-morbidities that appear resistant to traditional lifestyle interventions. However, recent progress identifying the molecular signaling pathways through which the brain and the gastrointestinal system communicate to govern energy homeostasis, combined with emerging insights on the molecular mechanisms underlying successful bariatric surgery, gives reason to be optimistic that novel precision medicines that mimic, enhance, and/or modulate gut-brain signaling can have unprecedented potential for stopping the obesity and type 2 diabetes pandemics.

Bariatric surgery may reduce the risk of Alzheimer's diseases through GLP-1 mediated neuroprotective effects

Obesity and diabetes are associated with deficits in multiple neurocognitive domains and increased risk for dementia. Over the last two decades, there has been a significant increase in bariatric and metabolic surgery worldwide, driven by rising intertwined pandemics of obesity and diabetes, along with improvement in surgical techniques. Patients undergoing bariatric surgery achieve a significant decrease in their excess weight and a multitude of sequela associated with obesity, diabetes, and metabolic syndrome. Glucagon-like peptide 1 (GLP-1) is an intestinal peptide that has been implicated as one of the weight loss-independent mechanisms in how bariatric surgery affects type 2 diabetes. GLP-1 improves insulin secretion, inhibits apoptosis and induce pancreatic islet neogenesis, promotes satiety, and can regulate heart rate and blood pressure. Moreover, numerous studies have demonstrated potential neuroprotective and neurotrophic effects of GLP-1. Increased GLP-1 activity has been shown to increase cortical activity, promote neuronal growth, and inhibit neuronal degeneration. Specifically, in experimental studies on Alzheimer's disease, GLP-1 decreases amyloid deposition and neurofibrillary tangles. Furthermore, recent studies have also suggested that GLP-1 based therapies, new class of antidiabetic drugs, have favorable effects on neurodegenerative disorders such as Alzheimer's disease. We present a hypothesis that bariatric surgery can help delay or even prevent the onset of Alzheimer's disease in long-term by increasing the levels of GLP-1. This hypothesis has a potential for many studies from basic science projects to large population studies to fully understand the neurological and cognitive consequences of bariatric surgery and associated rise in GLP-1.

Bariatric surgery and obesity: influence on the incretins

The gut hormone incretins have an important physiological role in meal-related insulin release and post-prandial glucose control. In addition to weight loss, the incretin hormones have a role in glucose control after bariatric surgery. The release of incretins, and specifically of glucagon-like peptide (GLP)-1, in response to the ingestion of nutrients, is greatly enhanced after gastric bypass (RYGBP). The rapid transit of food from the gastric pouch to the distal ileum is responsible for the greater GLP-1 release after RYGBP. The incretin effect on insulin secretion, or the greater insulin response to oral glucose compared to an isoglycemic intravenous glucose challenge, is severely impaired in patients with type 2 diabetes, but is recovered rapidly after RYGBP. The improvement in insulin secretion rate and β-cell sensitivity to oral glucose after RYGBP is mediated by endogenous GLP-1, and is abolished by exendin 9-39, a specific GLP-1 receptor antagonist. While calorie restriction and weight loss have major effects on the rapid and sustained improvement of fasted glucose metabolism, the enhanced incretin effect is a key player in post-prandial glucose control after RYGBP.

Unimolecular Polypharmacy for Treatment of Diabetes and Obesity

Many complex diseases have historically proven to be defiant to the best mono-therapeutic approaches. Several examples of combination therapies have largely overcome such challenges, notably for the treatment of severe hypertension and tuberculosis. Obesity and its consequences, such as type 2 diabetes, have proven to be equally resistant to therapeutic approaches based on single medicines. Proper management of type 2 diabetes often requires adjunctive medications, and the recent registration of a few compound mixtures has set the precedent for combinatorial treatment of obesity. On the other hand, double or triple therapeutic combinations are more difficult to advance to regulatory approval than single molecules. More recently, several classes of novel unimolecular combination therapeutics have emerged with superior efficacy than currently prescribed options and pose the potential to reverse obesity and type 2 diabetes. Here, we summarize the discovery, pre-clinical validation, and first clinical test of such peptide hormone poly-agonist drug candidates.

Mechanisms of surgical control of type 2 diabetes: GLP-1 is key factor

GLP-1 secretion in response to meals is dramatically increased after gastric bypass operations. GLP-1 is a powerful insulinotropic and anorectic hormone, and analogs of GLP-1 are widely used for the treatment of diabetes and recently approved also for obesity treatment. It is, therefore, reasonable to assume that the exaggerated GLP-1 secretion contributes to the antidiabetic and anorectic effects of gastric bypass. Indeed, human experiments with the GLP-1 receptor antagonist, Exendin 9-39, have shown that the improved insulin secretion, which is responsible for part of the antidiabetic effect of the operation, is reduced and or abolished after GLP-1 receptor blockade. Also the postoperative improvement of glucose tolerance is eliminated and or reduced by the antagonist, pointing to a key role for the exaggerated GLP-1 secretion. Indeed, there is evidence that the exaggerated GLP-1 secretion is also responsible for postprandial hypoglycemia sometimes observed after bypass. Other operations (biliopancreatic-diversion and or sleeve gastrectomy) appear to involve different and/or additional mechanisms, and so does experimental bariatric surgery in rodents. However, unlike bypass surgery in humans, the rodent operations are generally associated with increased energy metabolism pointing to an entirely different mechanism of action in the animals.

Long-term effects of duodenojejunal bypass on diabetes in Otsuka Long-Evans Tokushima Fatty rats

BACKGROUND

Previous studies have shown that duodenojejunal bypass (DJB) resolves type 2 diabetes. However, this finding has been contradicted by several experimental and human trials and therefore needs to be clarified.

METHODS

Otsuka Long-Evans Tokushima Fatty (OLETF) rats randomly underwent a sham operation or DJB. Thereafter, we measured daily body weight, serum levels of glucose and gut hormones such as glucagon-like peptide-1, insulin, and leptin.

RESULTS

There was no significant difference in weight loss between rats in the DJB and sham-operated groups. There were also no differences in the area under the curve of glucose tolerance between the DJB and sham-operated groups (32466 ± 2261 mg/dL·min vs. 26319 ± 427 mg/dL·min; p = 0.35). Duodenojejunal bypass did not affect plasma concentrations of various gut hormones such as glucagon-like peptide-1, insulin, and leptin.

CONCLUSIONS

We have shown that DJB alone does not improve glucose tolerance in obese, diabetic OLETF rats. Therefore, it may be that DJB alone is insufficient for diabetic control in obese diabetic rats. The addition of a restrictive component such as sleeve gastrectomy, or a new drug may be necessary for achieving diabetes reversal.

Safety and efficacy of a side-to-side duodeno-ileal anastomosis for weight loss and type-2 diabetes: duodenal bipartition, a novel metabolic surgery procedure

Background

Partial bypass of the GI tract may promote weight loss by decreased absorption of nutrients and changes in incretins. The aim of the study was to evaluate the safety and efficacy of performing a side-to-side duodeno-ileal anastomosis.

Methods

Seven 40–50 kg female Yorkshire pigs were allocated to a duodeno-ileal anastomosis (DIA), and were compared to a control group (SHAM). Swine’s weights were followed for 56 days. Gastroscopies were also performed at 28 days. Blood samples were also taken at regular intervals (CBC and Basic biochemistry profiles). At autopsy, gross changes and histological changes of the liver, duodenum and ileum samples were performed.

Results

While the SHAM group gained 33.2 % more weight at 56 days, the DIA group had shown a weight loss of −6.8 %, for a difference of 40.0 % between the 2 groups (p < 0.05). One pig developed an incisional hernia. Gastroscopies demonstrated normal healing without ulceration or inflammation at 28 days. Histological examination of the anastomosis at 56 days showed normal and smooth healing, with absence of liver toxicity.

Conclusion

In this porcine model with short follow-up, a side-to-side duodeno-ileal anastomosis provided excellent weight loss without apparent nutritional or grossly aberrant histological changes.

Effectiveness of Minimally Invasive Hybrid Surgery for Ileal Interposition (MIHSII) for the Resolution of Type 2 Diabetes

AIM

To evaluate the effectiveness of minimally invasive hybrid surgery for ileal interposition (MIHSII), a novel procedure for type 2 diabetes (T2DM) in patients with a body mass index (BMI) <30 kg⁄m(2).

MATERIALS AND METHODS

MIHSII is an innovative technique in which sleeve gastrectomy is performed laparoscopically, followed by extracorporeal ileal interposition performed through a 5-cm midline incision. The procedure was performed on 31 T2DM patients, 17 males and 14 females. Their BMI values ranged from 21.8 kg/m(2) to 29.8 kg/m(2), with a mean BMI of 26.61 ± 2.61 kg/m(2). The average duration of diabetes 8.14 ± 4.89 (range = 1-20) years. Most of the patients exhibited poorly controlled diabetes despite the use of oral hypoglycemic agents (OHAs) and/or insulin.

RESULTS

The mean preoperative glycosylated hemoglobin (HbA1c) for the population was 8.86%. The mean HbA1c 1 year after surgery was 6.80%. The difference between the mean preoperative and 1-year postoperative HbA1c values was significant, at P < .05 (group 1: BMI = 18.5-24.99 kg/m(2), t = 2.83, and P = .022; group 2: BMI = 25-29.99 kg/m(2), t = 4.23, and P = .001). The resolution rate of diabetes was 80.48%; 48.57% experienced complete resolution, and 31.91% experienced partial resolution. The remaining 19.52% of patients exhibited a significant reduction in HbA1c, although the HbA1c levels did not fall below 6.5%, even with medications.

CONCLUSION

MIHSII is an innovative technique of metabolic surgery and is a cost-effective and minimal procedure for the resolution of T2DM in patients with BMI <30 kg/m(2).

Insulin combined with Chinese medicine improves glycemic outcome through multiple pathways in patients with type 2 diabetes mellitus

Introduction/Aims

Insufficient insulin secretion or inefficient insulin response are responsible for the clinical outcome of type 2 diabetes mellitus. Administration of insulin alone is prone to cause secondary effects, resulting in an unsatisfactory outcome. Shen-Qi-Formula (SQF), a well-known Chinese medicinal formula, has been used for diabetic treatment for a long time. The present study was designed to investigate whether SQF in combination with insulin improved the clinical outcome of type 2 diabetes mellitus, and what mechanisms were possibly involved in the treatment.

Materials and Methods

A total of 219 patients were included in the study. Of these, 110 patients were treated with insulin monotherapy, and 109 with the combination therapy of SQF and insulin. Before and after 12-week treatment, the fasting blood glucose, postprandial blood glucose, β-cell function, insulin resistance and blood lipids were measured.

Results

The 12 weeks of SQF treatment in combination with insulin significantly decreased the fasting and postprandial blood glucose levels. Insulin secretion was not increased after the treatment, but β-cell function and insulin resistance were obviously improved. Furthermore, 12 weeks of treatment with SQF and insulin improved the levels of glucagon-like peptide-1, oxidative stress, blood lipids, coagulation function and bodyweight.

Conclusion

The results from our study showed that the combination therapy of SQF and insulin significantly improved the clinical outcome of type 2 diabetes mellitus compared with insulin monotherapy. The mechanism of improvement was possibly involved in the multiple pathways.

Comparison of ghrelin plasma levels between pre and postoperative period in patients submitted to gastric plication associated with fundoplication

BACKGROUND

The recurrence of the gastroesophageal reflux disease may be related to later postoperative weight gain, therefore increasing the chances of developing columnar metaplasia and cancer. The gastric plication associated with fundoplication can be employed in order to be treating the two issues.

AIM

To evaluate the serum ghrelin hormone in pre and postoperatively as well as weight loss and control of reflux disease in patients undergoing gastroplication associated with fundoplication.

METHODS

Was performed laparoscopic gastric plication with fundoplication in eight patients; endoscopic examinations were performed pre and postoperatively as well as blood collection for ghrelin hormonal dosage.

RESULTS

There was control of reflux symptoms and mucosal lesions. Weight loss was significant. Since the change of the hormone ghrelin was not of great significance.

CONCLUSIONS

Gastric plication associated with fundoplication was effective in treating reflux disease with surgical indication and for weight loss in obese patients. Appetite control occurs, but not due to ghrelin, because no significant decrease of its plasmatic levels was observed.

Braun gastrointestinal bypass surgery exerts similar hypoglycemic effects, with minimal operation time and earlier functional recovery, than Roux-en-Y bypass in type 2 diabetic rats

BACKGROUND

Despite the beneficial hypoglycemic and potentially curative effects in type 2 diabetes, large stomach volume deficits caused by Roux-en-Y gastrointestinal bypass (RYGB) surgery increase complications. Hypoglycemic effects of Braun surgery and RYGB surgery, both modified to maximally preserve stomach volume, were compared in rat type 2 diabetes models.

METHODS

Three-month-old, male Goto-Kakizaki (GK) rats (n = 40) were randomly divided into equal groups and not treated (control) or treated with sham surgery (sham group), modified stomach-preserving Braun gastrointestinal bypass (Braun group), or modified RYGB (RYGB group). Pre- and postoperative body weight and water intake were recorded, along with operative and defecation times. Fasting blood glucose at 12 h, and blood glucose 180 min after intragastric glucose administration, were measured at weeks 1, 2, 3, 4, 10, and 11 along with glycosylated hemoglobin (preoperatively, week 11).

RESULTS

Statistically similar (P > 0.05) increased body weight and decreased water intake, fasting blood glucose, blood glucose after intragastric glucose administration, and glycosylated hemoglobin were observed in Braun and RYGB groups compared with control and sham groups (P < 0.05). By week 1, RYGB and Braun groups exhibited sustained reductions in fasting blood glucose from 13.0 ± 4.1 to 6.9 ± 1.4 mmol/L and 12.4 ± 4.4 to 7.3 ± 0.9 mmol/L, respectively (P < 0.05); mean operative times were 139.1 ± 4.9 and 81.6 ± 6.4 min, respectively; and postoperative defecation times were 74.3 ± 3.1 and 29.4 ± 4.1 h, respectively (P < 0.05).

CONCLUSIONS

Stomach volume-preserving Braun gastrointestinal bypass surgery was faster and produced hypoglycemic effects similar to RYGB bypass surgery, potentially minimizing metabolic disruption.

Incretin hormones and the satiation signal

Recent research has indicated that appetite-regulating hormones from the gut may have therapeutic potential. The incretin hormone, glucagon-like peptide-1 (GLP-1), appears to be involved in both peripheral and central pathways mediating satiation. Several studies have also indicated that GLP-1 levels and responses to meals may be altered in obese subjects. Clinical trial results have shown further that two GLP-1 receptor agonists (GLP-1 RAs), exenatide and liraglutide, which are approved for the treatment of hyperglycemia in patients with type 2 diabetes, also produce weight loss in overweight subjects without diabetes. Thus, GLP-1 RAs may provide a new option for pharmacological treatment of obesity.

Exaggerated glucagon-like peptide 1 response is important for improved β-cell function and glucose tolerance after Roux-en-Y gastric bypass in patients with type 2 diabetes

β-Cell function improves in patients with type 2 diabetes in response to an oral glucose stimulus after Roux-en-Y gastric bypass (RYGB) surgery. This has been linked to the exaggerated secretion of glucagon-like peptide 1 (GLP-1), but causality has not been established. The aim of this study was to investigate the role of GLP-1 in improving β-cell function and glucose tolerance and regulating glucagon release after RYGB using exendin(9-39) (Ex-9), a GLP-1 receptor (GLP-1R)-specific antagonist. Nine patients with type 2 diabetes were examined before and 1 week and 3 months after surgery. Each visit consisted of two experimental days, allowing a meal test with randomized infusion of saline or Ex-9. After RYGB, glucose tolerance improved, β-cell glucose sensitivity (β-GS) doubled, the GLP-1 response greatly increased, and glucagon secretion was augmented. GLP-1R blockade did not affect β-cell function or meal-induced glucagon release before the operation but did impair glucose tolerance. After RYGB, β-GS decreased to preoperative levels, glucagon secretion increased, and glucose tolerance was impaired by Ex-9 infusion. Thus, the exaggerated effect of GLP-1 after RYGB is of major importance for the improvement in β-cell function, control of glucagon release, and glucose tolerance in patients with type 2 diabetes.

Predictors for remission of major components of the metabolic syndrome after biliopancreatic diversion with duodenal switch (BPDDS)

BACKGROUND

Metabolic surgery causes the remission of type 2 diabetes mellitus (T2DM), hypertension, and hyperlipidemia to varying degrees, depending on the patient characteristics and the surgical procedure. The aim of this study was to find predictors for the remission of T2DM and hypertension after biliopancreatic diversion with duodenal switch (BPDDS).

METHODS

Eighty patients with T2DM were followed up for 2 years or more after BPDDS, and changes in body weight and metabolic status were noted. Remission was defined as fasting glucose <7 mmol/l with HbA1C <6.5 %, blood pressure <140/90 mmHg, and low-density lipoprotein (LDL) <2.6 mmol without the use of medication.

RESULTS

Preoperatively, the mean age was 44 years, body mass index (BMI) was 48 kg/m(2), and duration of diabetes was 5 years. Of the 80 patients, 38 patients were using insulin, 48 patients were using antihypertensives, and 38 patients were using a lipid-lowering drug. Five percent of the patients had recommended levels for HbA1C, blood pressure, and LDL prior to the operation. The remission rate at 2 years was 94 % for T2DM, 54 % for hypertension, and 86 % for LDL hyperlipidemia. Preoperative predictors for nonremission of T2DM were a higher BMI, insulin usage, and low insulin C-peptide, and for hypertension, older age and more severe hypertension. Postoperative weight loss was important for both.

CONCLUSIONS

Surgical intervention with BPDDS is an effective treatment of T2DM, hypertension, and hyperlipidemia. The duration of T2DM and age of the patient are the most important preoperative predictors for the remission of T2DM and hypertension, respectively.

Herbal therapies for type 2 diabetes mellitus: chemistry, biology, and potential application of selected plants and compounds

Diabetes mellitus has been recognized since antiquity. It currently affects as many as 285 million people worldwide and results in heavy personal and national economic burdens. Considerable progress has been made in orthodox antidiabetic drugs. However, new remedies are still in great demand because of the limited efficacy and undesirable side effects of current orthodox drugs. Nature is an extraordinary source of antidiabetic medicines. To date, more than 1200 flowering plants have been claimed to have antidiabetic properties. Among them, one-third have been scientifically studied and documented in around 460 publications. In this review, we select and discuss blood glucose-lowering medicinal herbs that have the ability to modulate one or more of the pathways that regulate insulin resistance, β-cell function, GLP-1 homeostasis, and glucose (re)absorption. Emphasis is placed on phytochemistry, anti-diabetic bioactivities, and likely mechanism(s). Recent progress in the understanding of the biological actions, mechanisms, and therapeutic potential of compounds and extracts of plant origin in type 2 diabetes is summarized. This review provides a source of up-to-date information for further basic and clinical research into herbal therapy for type 2 diabetes. Emerging views on therapeutic strategies for type 2 diabetes are also discussed.

Herbal therapies for type 2 diabetes mellitus: chemistry, biology, and potential application of selected plants and compounds

Background:

Diabetes mellitus, becoming the third killer of mankind after cancer and cardiovascular diseases, is one of the most challenging diseases facing health care professionals today. That is why; there has been a growing interest in the therapeutic use of natural products for diabetes, especially those derived from plants.

Aim:

To evaluate the anti-diabetic activity together with the accompanying biological effects of the fractions and the new natural compounds of Hyphaene thebaica (HT) epicarp.

Materials and Methods:

500 g of coarsely powdered of (HT) fruits epicarp were extracted by acetone. The acetone crude extract was fractionated with methanol and ethyl acetate leaving a residual water-soluble fraction WF. The anti-diabetic effects of the WF and one of its compounds of the acetone extract of the (HT) epicarp were investigated in this study using 40 adult male rats.

Results:

Phytochemical investigation of active WF revealed the presence of ten different flavonoids, among which two new natural compounds luteolin 7-O-[6”-O-α-Lrhamnopyranosyl]-β-D-galactopyranoside 3 and chrysoeriol 7-O-β-D-galactopyranosyl(1→2)-α-L-arabinofuranoside 5 were isolated. Supplementation of the WF improved glucose and insulin tolerance and significantly lowered blood glycosylated hemoglobin levels. On the other hand, compound 5 significantly reduced AST and ALT levels of liver, respectively. Likewise, the kidney functions were improved for both WF and compound 5, whereby both urea and creatinine levels in serum were highly significant

Conclusion:

The results justify the use of WF and compound 5 of the (HT) epicarp as anti-diabetic agent, taking into consideration that the contents of WF were mainly flavonoids

Effects of bariatric surgery on adipokine-induced inflammation and insulin resistance

Over a third of the US population is obese and at high risk for developing type 2 diabetes, insulin resistance, and other metabolic disorders. Obesity is considered a chronic low-grade inflammatory condition that is primarily attributed to expansion and inflammation of adipose tissues. Indeed, adipocytes produce and secrete numerous proinflammatory and anti-inflammatory cytokines known as adipokines. When the balance of these adipokines is shifted toward higher production of proinflammatory factors, local inflammation within adipose tissues and subsequently systemic inflammation occur. These adipokines including leptin, visfatin, resistin, apelin, vaspin, and retinol binding protein-4 can regulate inflammatory responses and contribute to the pathogenesis of diabetes. These effects are mediated by key inflammatory signaling molecules including activated serine kinases such as c-Jun N-terminal kinase and serine kinases inhibitor κB kinase and insulin signaling molecules including insulin receptor substrates, protein kinase B (PKB, also known as Akt), and nuclear factor kappa B. Bariatric surgery can decrease body weight and improve insulin resistance in morbidly obese subjects. However, despite reports suggesting reduced inflammation and weight-independent effects of bariatric surgery on glucose metabolism, mechanisms behind such improvements are not yet well understood. This review article focuses on some of these novel adipokines and discusses their changes after bariatric surgery and their relationship to insulin resistance, fat mass, inflammation, and glucose homeostasis.

Comparison of Bariatric Surgical Procedures for Diabetes Remission: Efficacy and Mechanisms

Bariatric surgery induces a mean weight loss of 15-30% of initial body weight (depending on the procedure), as well as a 45-95% rate of diabetes remission. Procedures that induce greater weight loss are associated with higher rates of diabetes remission. Improvements in glucose homeostasis after bariatric surgery are likely mediated by a combination of caloric restriction (followed by weight loss) and the effects of altered gut anatomy on the secretion of glucoregulatory gut hormones.

Effects of bariatric surgery on glucose homeostasis and type 2 diabetes

Obesity is an important risk factor for type 2 diabetes mellitus (T2DM). Weight loss improves the major factors involved in the pathogenesis of T2DM, namely insulin action and beta cell function, and is considered a primary therapy for obese patients who have T2DM. Unfortunately, most patients with T2DM fail to achieve successful weight loss and adequate glycemic control from medical therapy. In contrast, bariatric surgery causes marked weight loss and complete remission of T2DM in most patients. Moreover, bariatric surgical procedures that divert nutrients away from the upper gastrointestinal tract are more successful in producing weight loss and remission of T2DM than those that simply restrict stomach capacity. Although upper gastrointestinal tract bypass procedures alter the metabolic response to meal ingestion, by increasing early postprandial plasma concentrations of glucagon-like peptide 1 and insulin, it is not clear whether these effects make an important contribution to long-term control of glycemia and T2DM once substantial surgery-induced weight loss has occurred. Nonetheless, the effects of surgery on body weight and metabolic function indicate that bariatric surgery should be part of the standard therapy for T2DM. More research is needed to advance our understanding of the physiological effects of different bariatric surgical procedures and possible weight loss-independent factors that improve metabolic function and contribute to the resolution of T2DM.

Regulation of mouse intestinal L cell progenitors proliferation by the glucagon family of peptides

Glucagon like peptide-1 (GLP-1) and GLP-2 are hormones secreted by intestinal L cells that stimulate glucose-dependent insulin secretion and regulate intestinal growth, respectively. Mice with deletion of the glucagon receptor (Gcgr) have high levels of circulating GLP-1 and GLP-2. We sought to determine whether the increased level of the glucagon-like peptides is due to L cell hyperplasia. We found, first, that high levels of the glucagon-like peptides increase L cell number but does not affect the number of other intestinal epithelial cell types. Second, a large proportion of ileal L cells of Gcgr(-/-) mice coexpressed glucose-dependent insulinotropic peptide (GIP). Cells coexpressing GIP and GLP-1 are termed LK cells. Third, the augmentation in L cell number was due to a higher rate of proliferation of L cell progenitors rather than to the entrance of mature L cells into the cell cycle. Fourth, a high concentration of the glucagon-like peptides in the circulation augmented the mRNA levels of transcription factors expressed by late but not early enteroendocrine progenitors. Fifth, the administration of exendin 9-39, a GLP-1 receptor antagonist, resulted in a decrease in the rate of L cell precursor proliferation. Finally, we determined that L cells do not express the GLP-1 receptor, suggesting that the effect of GLP-1 is mediated by paracrine and/or neuronal signals. Our results suggest that GLP-1 plays an important role in the regulation of L cell number.

Gut feelings about diabetes

Studies of patients going into diabetes remission after gastric bypass surgery have demonstrated the important role of the gut in glucose control. The improvement of type 2 diabetes after gastric bypass surgery occurs via weight dependent and weight independent mechanisms. The rapid improvement of glucose levels within days after the surgery, in relation to change of meal pattern, rapid nutrient transit, enhanced incretin release and improved incretin effect on insulin secretion, suggest mechanisms independent of weight loss. Alternatively, insulin sensitivity improves over time as a function of weight loss. The role of bile acids and microbiome in the metabolic improvement after bariatric surgery remains to be determined. While most patients after bariatric surgery experienced sustained weight loss and improved metabolism, small scale studies have shown weight regain and diabetes relapse, the mechanisms of which remain unknown.

Early improvement in glycemic control after bariatric surgery and its relationships with insulin, GLP-1, and glucagon secretion in type 2 diabetic patients

BACKGROUND

The surgical treatment of obesity ameliorates metabolic abnormalities in patients with type 2 diabetes. The objective of this study was to evaluate the early effects of Roux-en-Y gastric bypass (RYGB) on metabolic and hormonal parameters in patients with type 2 diabetes (T2DM).

METHODS

Ten patients with T2DM (BMI, 39.7 ± 1.9) were evaluated before and 7, 30, and 90 days after RYGB. A meal test was performed, and plasma insulin, glucose, glucagon, and glucagon-like-peptide 1 (GLP-1) levels were measured at fasting and postprandially.

RESULTS

Seven days after RYGB, a significant reduction was observed in HOMA-IR index from 7.8 ± 5.5 to 2.6 ± 1.7; p < 0.05 was associated with a nonsignificant reduction in body weight. The insulin and GLP-1 curves began to show a peak at 30 min after food ingestion, while there was a progressive decrease in glucagon and blood glucose levels throughout the meal test. Thirty and 90 days after RYGB, along with progressive weight loss, blood glucose and hormonal changes remained in the same direction and became more expressive with the post-meal insulin curve suggesting recovery of the first phase of insulin secretion and with the increase in insulinogenic index, denoting improvement in β-cell function. Furthermore, a positive correlation was found between changes in GLP-1 and insulin levels measured at 30 min after meal (r = 0.6; p = 0.000).

CONCLUSION

Our data suggest that the RYGB surgery, beyond weight loss, induces early beneficial hormonal changes which favor glycemic control in type 2 diabetes.

Diabetes remission after bariatric surgery: is it just the incretins?

Gastric bypass surgery (GBP) results in important and sustained weight loss and remarkable improvement of Type 2 diabetes. The favorable change in the incretin gut hormones is thought to be responsible, in part, for diabetes remission after GBP, independent of weight loss. However, the relative role of the change in incretins and of weight loss is difficult to differentiate. After GBP, the plasma concentrations of the incretin hormones glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide increase postprandially by three- to fivefold. The postprandial incretin effect on insulin secretion, blunted in diabetes, improves rapidly after the surgery. In addition to the change in incretins, the pattern of insulin secretion in response to oral glucose changes after GBP, with recovery of the early phase and significant decrease in postprandial glucose levels. These changes were not seen after an equivalent weight loss by diet. The improved insulin release and glucose tolerance after GBP were shown by others to be blocked by the administration of a GLP-1 antagonist, demonstrating that the favorable metabolic changes after GBP are, in part, GLP-1 dependent. The improved incretin levels and effect persist years after GBP, but their long-term effect on glucose metabolism, and on hypoglycemia post GBP are yet unknown. Understanding the mechanisms by which incretin release is exaggerated postprandially after GBP may help develop new less invasive treatment options for obesity and diabetes. Changes in rate of eating, gastric emptying, intestinal transit time, nutrient absorption and sensing, as well as bile acid metabolism, may all be implicated.

Update: Why diabetes does not resolve in some patients after bariatric surgery

Bariatric surgery provides resolution of co-morbidities of morbid obesity-importantly diabetes type 2. This is initiated by immediate postoperative decrease in intake or assimilation of glucose and is continued by the substantial loss of adipose tissue. Greater weight loss and greater resolution of type 2 diabetes occur after operations that provide rapid passage of nutrients to the hindgut, which likely results in beta-cell stimulation by incretins. Failure of resolution of the diabetes can result from lack of patient compliance, inadequate weight loss, longstanding uncontrolled diabetes, or when the diabetes is actually a type 1.

Resolution of diabetes mellitus by ileal transposition compared with biliopancreatic diversion in a nonobese animal model of type 2 diabetes

BACKGROUND

It has been demonstrated that biliopancreatic diversion (BPD) and ileal transposition (IT) effectively induce weight loss and long-term control of type 2 diabetes in morbidly obese individuals. It is unknown whether the control of diabetes is better after IT or after BPD. The objective of this study was to investigate the effects of IT and BPD on the control of diabetes in an animal model.

METHODS

We performed IT and BPD on 10- to 12-week-old Goto-Kakizaki rats with a spontaneous nonobese model of type 2 diabetes, and we performed a series of detection. The rats were observed for 24 weeks after surgery.

RESULTS

Animals who underwent IT and BPD demonstrated improved glucose tolerance, insulin sensitivity and the secretion of glucagon-like peptide-1 compared with the sham-operated animals. Furthermore, IT resulted in a shorter duration of surgery and better postoperative recovery than BPD.

CONCLUSION

This study provides strong evidence for the crucial role of the hindgut in the resolution of diabetes after duodenum-jejunum bypass or IT. We confirmed that IT was associated with better postoperative recovery than BPD and had a similar control of diabetes as BPD in nonobese animals with type 2 diabetes.

DA-1229, a novel and potent DPP4 inhibitor, improves insulin resistance and delays the onset of diabetes

AIM

To characterize the pharmacodynamic profile of DA-1229, a novel dipeptidyl peptidase (DPP) 4 inhibitor.

MAIN METHODS

Enzyme inhibition assays against DPP4, DPP8 and DPP9. Antidiabetic effects of DA-1229 in HF-DIO mice and young db/db mice.

KEY FINDINGS

DA-1229 was shown to potently inhibit the DPP4 enzyme in human and murine soluble forms and the human membrane-bound form with IC(50) values of 0.98, 3.59 and 1.26 nM, respectively. As a reversible and competitive inhibitor, DA-1229 was more selective to human DPP4 (6000-fold) than to human DPP8 and DPP9. DA-1229 (0.1-3mg/kg) dose-dependently inhibited plasma DPP4 activity, leading to increased levels of plasma GLP-1 and insulin, and thereby lowering blood glucose levels in mice. In high fat diet-fed (HF) mice, a single oral dose of 100mg/kg of DA-1229 reduced plasma DPP4 activity by over 80% during a 24h period. Long-term treatment with DA-1229 for 8 weeks revealed significant improvements in glucose intolerance and insulin resistance, accompanied by significant body weight reduction. However, it remains unclear whether there is a direct causal relationship between DPP4 inhibition and body weight reduction. In young db/db mice, the DA-1229 treatment significantly reduced blood glucose excursions for the first 2 weeks, resulting in significantly lower levels of HbA1c at the end of the study. Furthermore, the pancreatic insulin content of the treatment group was significantly higher than that of the db/db control.

SIGNIFICANCE

DA-1229 as a novel and selective DPP4 inhibitor improves the insulin sensitivity in HF mice and delays the onset of diabetes in young db/db mice.

Do we really know why diabetes remits after gastric bypass surgery?

Roux-en-Y gastric bypass surgery (GBP) results in 30-40% sustained weight loss and improved type 2 diabetes in up to 80% of patients. The relative contribution of the gut neuroendocrine changes after GBP versus the weight loss has not been fully elucidated. There are clear differences between weight loss by GBP and by dietary intervention or gastric banding. One of them is the enhanced post-prandial release of incretin hormones and the recovery of the incretin effect on insulin secretion after GBP, not seen after diet-induced weight loss. The favorable changes in incretin hormones after GBP result in recovery of the early phase insulin secretion and lower post-prandial glucose levels during oral glucose administration. The enhanced incretin response may be related to the neuroglycopenia post-GBP. In parallel with changes of glucose metabolism, a larger decrease of circulating branched-chain amino acids in relation to improved insulin sensitivity and insulin secretion is observed after GBP compared to diet. The mechanisms of the rapid and longterm endocrine and metabolic changes after GBP are not fully elucidated. Changes in rate of eating, gastric emptying, nutrient absorption and sensing, bile acid metabolism, and microbiota may all be important. Understanding the mechanisms by which incretin release is exaggerated post-prandially after GBP may help develop new less invasive treatment options for obesity and diabetes. Equally important would be to identify biological predictors of success or failure and to understand the mechanisms of weight regain and/or diabetes relapse.

Surgical approaches to the treatment of obesity: bariatric surgery

As the obesity epidemic continues to grow in the Unites States, so does the search for the ideal nonsurgical or surgical solution. Bariatric surgery continues to be the most sustainable form of weight loss available to morbidly obese patients. In addition, bariatric surgery has established an acceptable safety profile with respect to morbidity and mortality. With the number of elective bariatric cases growing in recent years, it is unsurprising that results have improved and better data are emerging regarding improvement of obesity-related comorbid conditions. Additionally, ample evidence suggests that bariatric surgery may increase longevity, particularly through reducing cardiovascular deaths. Although the specific mechanisms involved in the remission of these medical conditions remain to be fully elucidated, it has become clear that bariatric surgery has established a significant and firm role in the treatment of medical comorbidities that result directly from obesity. However, until commercial insurance carriers provide improved coverage for bariatric surgery, patient access to these treatments will remain limited.

GIP and bariatric surgery

Bariatric surgery is the most effective modality of achieving weight loss as well as the most effective treatment for type 2 diabetes mellitus (T2DM). Glucose-dependent insulinotropic polypeptide (GIP) is an incretin and is implicated in the pathogenesis of obesity and T2DM. Its role in weight loss and resolution of T2DM after bariatric surgery is very controversial. We have made an attempt to review the physiology of GIP and its role in weight loss and resolution of T2DM after bariatric surgery. We searched PubMed and included all relevant original articles (both human and animal) in the review. Whereas most human studies have shown a decrease in GIP post-malabsorptive bariatric surgery, the role of GIP in bariatric surgery done in animal experiments remains inconclusive.

Roux-en-Y gastric bypass and laparoscopic sleeve gastrectomy: understanding weight loss and improvements in type 2 diabetes after bariatric surgery

Obesity increases the likelihood of diseases like type 2 diabetes (T2D), heart disease, and cancer, and is one of the most serious public health problems of this century. In contrast to ineffectual prevention strategies, lifestyle modifications, and pharmacological therapies, bariatric surgery is a very effective treatment for morbid obesity and also markedly improves associated comorbidities like T2D. However, weight loss and resolution of T2D after bariatric surgery is heterogeneous and specific to type of bariatric procedure performed. Conventional mechanisms like intestinal malabsorption and gastric restriction do not fully explain this, and potent changes in appetite and the enteroinsular axis, as a result of anatomical reorganization and altered hormonal, neuronal, and nutrient signaling, are the portended cause. Uniquely these signaling changes appear to override vigorous homeostatic defenses of stable body weight and compelling self-gratifying motivations to eat and to reverse defects in beta-cell function and insulin sensitivity. Here we review mechanisms of weight loss and T2D resolution after Roux-en-Y gastric bypass and laparoscopic sleeve gastrectomy bariatric surgery, two markedly different procedures with robust clinical outcomes.

Mechanisms facilitating weight loss and resolution of type 2 diabetes following bariatric surgery

Bariatric surgery is the most effective treatment modality for obesity, resulting in durable weight loss and amelioration of obesity-associated comorbidities, particularly type 2 diabetes mellitus (T2DM). Moreover, the metabolic benefits of bariatric surgery occur independently of weight loss. There is increasing evidence that surgically induced alterations in circulating gut hormones mediate these beneficial effects of bariatric surgery. Here, we summarise current knowledge on the effects of different bariatric procedures on circulating gut hormone levels. We also discuss the theories that have been put forward to explain the weight loss and T2DM resolution following bariatric surgery. Understanding the mechanisms mediating these beneficial outcomes of bariatric surgery could result in new non-surgical treatment strategies for obesity and T2DM.

Effect of gastric bypass surgery on the incretins

AIMS

Our studies were designed to understand the role of the gut hormones incretins GLP-1 and GIP on diabetes remission after gastric bypass surgery (GBP).

METHODS

Morbidly obese patients with type 2 diabetes (T2DM) were studied before and 1, 6, 12, 24 and 36 months after GBP. A matched group of patients were studied before and after a diet-induced 10 kg weight loss, equivalent to the weight loss 1 month after GBP. All patients underwent an oral glucose tolerance test and an isoglycaemic glucose intravenous challenge to measure the incretin effect.

RESULTS

Post-prandial GLP-1 and GIP levels increase after GBP and the incretin effect on insulin secretion normalizes to the level of non diabetic controls. In addition, the pattern of insulin secretion in response to oral glucose changes after GBP, with recovery of the early phase, and post-prandial glucose levels decrease significantly. These changes were not seen after an equivalent weight loss by diet. The changes in incretin levels and effect observed at 1 month are long lasting and persist up to 3 years after the surgery. The improved insulin release and glucose tolerance after GBP were shown by others to be blocked by the administration of a GLP-1 antagonist in rodents, demonstrating that these metabolic changes are, in part, GLP-1 dependent.

CONCLUSION

Although sustained and significant weight loss is likely to be the key mediator of diabetes remission after GBP, the changes of incretins improve the early phase of insulin secretion and post-prandial glucose levels, and contribute to the better glucose tolerance.

Surgical approaches for the prevention and treatment of type 2 diabetes mellitus

Lifestyle modifications and pharmacologic therapy have been the mainstays of treatment for patients with type 2 diabetes mellitus. Bariatric surgery, originally designed as a weight loss treatment, has been proven to ameliorate and even cure diabetes. The significant improvement in glycemic control found after bariatric surgery in patients with diabetes often precedes major weight loss. Therefore, a weight-independent mechanism has been thought to initiate this amelioration in glucose control. Reviews of the recent literature question the goal of bariatric surgery, not only to treat obesity through restriction and malabsorption, but also as a possible treatment for diabetes regardless of the degree of obesity. Procedures such as Roux-en-Y gastric bypass, adjustable gastric banding, and biliopancreatic diversion have proven to be extremely effective in controlling diabetes mellitus. Mechanisms explaining the effectiveness of weight reduction surgery include effects on incretins, ghrelin secretion, and insulin sensitivity. Some centers have been performing gastric bypass surgeries on patients with a lower body mass index than that recommended by current NIH guidelines. New considerations for recommending bypass surgery are warranted as the indications for antiobesity surgeries grow to encompass both the treatment and cure of diabetes.

Sleeve gastrectomy provides a better control of diabetes by decreasing ghrelin in the diabetic Goto-Kakizaki rats

AIM

Sleeve gastrectomy (SG) and modified duodenal jejunal bypass (MDJB) were compared as procedures for glucose control. We aim to form the initial conclusions with respect to the possibility of (1) whether gastric fundus exclusion is essential for the control of diabetes and (2) application as a low morbidity procedure.

MATERIALS AND METHODS

SG and MDJB were performed on 10- to 12-week-old Goto-Kakizaki rats that spontaneously develop type 2 diabetes. Rats were observed for 36 weeks after surgery, and glucose, insulin, glucagons-like peptide-1 (GLP-1), glucose tolerate, insulin sensitivity, cholesterol, triglycerides, and free fatty acid levels were measured.

RESULTS

Apart from distinct weight loss of SG and MDJB after 1 month compared with sham-operated rats (P < 0.001), SG showed strikingly improved blood glucose levels and significantly decreased Ghrelin secretion (P < 0.001). Furthermore, SG resulted in a shorter operative time (P < 0.01) and postoperative recovery time (P < 0.01) than MDJB group.

CONCLUSIONS

SG shows better control in terms of glucose tolerance and other measurements. This study provides direct evidence that SG possesses better improvement of diabetes by reduction of Ghrelin.

Dissociated incretin response to oral glucose at 1 year after restrictive vs. malabsorptive bariatric surgery

AIM

Compare the response to oral glucose of the two incretin hormones, glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) at 1 year after restrictive vs. malabsorptive bariatric surgery.

METHODS

Vertical banded gastroplasty (VBG, n = 7) or jejunoileal bypass (JIB, n = 5) was performed in 12 women, aged 26-39 years, with severe obesity [body mass index (BMI) 46.6 +/- 2.3 kg/m(2)]. After 1 year, 75 g glucose was administered and plasma levels of glucose, insulin, GIP and GLP-1 were determined regularly during the following 2 h.

RESULTS

At 1 year after operation, reduction in body weight, actual body weight, fasting glucose or insulin, or the glucose and insulin responses to oral glucose did not differ significantly between the groups. Similarly, fasting GIP and GLP-1 levels did not differ significantly between the groups. In contrast, the GIP and GLP-1 responses to oral glucose were different between the groups in a dissociated pattern. Thus, AUC(GIP) was significantly higher after VBG than after JIB (53 +/- 8 vs. 26 +/- 6 pmol/l/min, p = 0.003). In contrast, AUC(GLP-1) was significantly higher after JIB than after VBG (49 +/- 5 vs. 20 +/- 3 pmol/l/min, p = 0.007).

CONCLUSIONS

We conclude that at 1 year after bariatric surgery, the two incretins show dissociated responses in that the GIP secretion is higher after VBG whereas GLP-1 secretion is higher after JIB. This dissociated incretin response is independent from reduction in body weight, glucose tolerance or insulin secretion.

Serum bile acid along with plasma incretins and serum high-molecular weight adiponectin levels are increased after bariatric surgery

Bariatric surgery has been shown to improve glucose tolerance, although the mechanism has not been fully elucidated. Animal studies have suggested important roles of bile acid (BA) as a regulator of energy homeostasis and glucose metabolism. However, little is known about its role in humans. We investigated the longitudinal changes of BA, incretins, and adipokines after significant weight reduction in 34 Japanese adults with morbid obesity who underwent laparoscopic bariatric surgery. In subjects who underwent malabsorptive or restrictive surgery, body mass index had markedly decreased from 43.0 +/- 6.5 (SD) to 37.8 +/- 5.7 kg/m(2) and from 45.3 +/- 11.2 to 41.5 +/- 10.5 kg/m(2), respectively, at 1 month after surgery. Glycated hemoglobin decreased from 6.1% +/- 1.5% to 5.2% +/- 0.4% and from 6.2% +/- 1.3% to 5.4% +/- 0.7%, and total BA level increased from 3.1 +/- 3.5 to 7.2 +/- 5.3 mumol/L and from 3.2 +/- 2.6 to 9.4 +/- 10.0 mumol/L, respectively. At baseline, serum concentration of primary BA was positively correlated with plasma gastric inhibitory polypeptide level (r = 0.548, P = .001); and change in primary BA level was positively correlated with changes in plasma gastric inhibitory polypeptide (r = 0.626, P = .001) and serum immunoreactive insulin level (r = 0.592, P = .002) at 1 month after surgery. Furthermore, plasma glucagon-like peptide-1 and serum high-molecular weight adiponectin levels increased in both surgeries. These hormonal changes might explain the mechanism(s) of improved glucose tolerance after bariatric surgery in morbidly obese subjects.

Mining incretin hormone pathways for novel therapies

The incretin hormones, glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1), are produced predominantly by enteroendocrine cells and have multiple blood glucose-lowering effects. Recent years have seen a surge of interest in understanding the basic physiology and pathophysiology of incretins and in applying this knowledge to the treatment of diabetes and obesity. Considerable gains have been made in elucidating the mechanisms controlling incretin secretion, and there is growing evidence to suggest that incretins might be involved in the rapid reversal of diabetes observed in gastric bypass patients. Here, we review these recent advances and outline the multiple strategies being pursued to exploit the potential therapeutic benefits of GIP and GLP-1.

Changes in physiology with increasing fat mass

Obesity has reached epidemic proportions in the USA with a nearly fourfold rise in the prevalence of childhood obesity. There are many possible etiologies of obesity as the adipose tissue plays a significant, complex role in the physiology of fuel metabolism and hormone regulation. The development of obesity represents a pathophysiologic increase in fat mass in which multiple metabolic pathways are deranged. The consequences of these metabolic derangements, including insulin resistance and inflammation, are reflected in obesity-related comorbidities and can be seen in the setting of pediatric obesity. Obese adolescents demonstrate increased rates of early maturation, orthopedic growth abnormalities, diabetes mellitus, obstructive sleep apnea, hypertension, steatosis, and polycystic ovarian syndrome, placing this group of children at risk for long-term health problems and reduced quality of life. Given the negative short- and long-term impact of obesity on children, careful attention should be paid to the unique health issues of this "at-risk" population with both prevention and early intervention strategies.