Restoration of acute insulin response in T2DM subjects 1 month after biliopancreatic diversion

Diabetes Resolution at 10 Years After Biliopancreatic Diversion in Overweight and Class 1 Obese Patients with Type 2 Diabetes

Background

Long-term anti-diabetic effects of BPD in overweight or class 1 obese T2DM patients were investigated reporting the results at 10 years after BPD performed in severely non-obese T2DM patients.

Material and Methods

Thirty T2DM patients with BMI lower than 35 kg/m² were investigated at 1, 5, and 10 years after BPD, and the results are compared with those of 30 T2DM patients followed for 10 years on pharmacological and/or behavioral conventional therapy.

Results

Mean levels of fasting blood glucose (FBG) and serum glycated hemoglobin (HbA1_C) showed a marked reduction 1 year after BPD, values remaining slightly above the diabetic range throughout the entire follow-up. T2DM remission was observed in about 50% of the cases at 5 and 10 years after the operation. In 16 patients (53%), severe BPD-related complications developed, in ten cases requiring a surgical revision of the operation. In the BPD group, one patient died for malignant lymphoma and two patients after surgical revision. Within the control group, during the 10-year follow-up, no changes in the diabetic status were observed, being the FBG and HbA1_C mean values higher than those recorded in the BPD patients at any follow-up time. All T2DM subjects of the control group were alive at the end of the 10-year follow-up.

Conclusion

Despite satisfactory long-term metabolic outcomes, these data indicate that BPD should be used with caution as a metabolic procedure in the treatment of T2DM in overweight or class 1obese patients.

Graphical abstract

Ten-year remission rates in insulin-treated type 2 diabetes after biliopancreatic diversion with duodenal switch

BACKGROUND

Biliopancreatic diversion with duodenal switch (BPD-DS) confers the highest rate of type 2 diabetes (T2D) remission compared with other bariatric procedures. Previous studies suggest that type of antidiabetic therapy used before surgery and duration of disease influence postsurgical glycemic outcomes. Short-term, progressive improvement in insulin sensitivity and beta-cell function after metabolic surgery in patients with noninsulin-treated T2D has been demonstrated. Whether patients with more advanced disease can achieve sustained remission remains unclear.

OBJECTIVE

The aim of this study was to assess long-term glycemic outcomes in insulin-treated patients with T2D after BPD-DS and identify predictors of sustained diabetes remission or relapse.

SETTING

University-affiliated tertiary care center.

METHODS

Data from 141 patients with insulin-treated T2D who underwent BPD-DS between 1994 and 2006 with 10 years of follow-up data were collected from a prospective electronic database.

RESULTS

Follow-up was available in 132 patients (91%). At 10 years after metabolic surgery, 90 patients (68.1%) had a complete remission of diabetes, 3 (2.3%) had a partial remission, 21 (15.9%) had an improvement, and 3 (2.3%) were unchanged in their diabetes status. Fourteen patients died during the 10-year follow-up period. Relapse after an initial period of remission occurred in 15 (11.4%) patients. Insulin discontinuation was achieved in 97%. Duration of diabetes was an independent predictor of nonremission at 10 years.

CONCLUSIONS

The BPD-DS maintains remission at 10 years postoperatively in patients with more advanced diabetes. Long-term benefits of the BPD-DS on weight loss and glycemic control should be considered when offering metabolic surgery to patients with insulin-treated T2D.

In Vitro Platform for Studying Human Insulin Release Dynamics of Single Pancreatic Islet Microtissues at High Resolution

Insulin is released from pancreatic islets in a biphasic and pulsatile manner in response to elevated glucose levels. This highly dynamic insulin release can be studied in vitro with islet perifusion assays. Herein, a novel platform to perform glucose-stimulated insulin secretion (GSIS) assays with single islets is presented for studying the dynamics of insulin release at high temporal resolution. A standardized human islet model is developed and a microfluidic hanging-drop-based perifusion system is engineered, which facilitates rapid glucose switching, minimal sample dilution, low analyte dispersion, and short sampling intervals. Human islet microtissues feature robust and long-term glucose responsiveness and demonstrate reproducible dynamic GSIS with a prominent first phase and a sustained, pulsatile second phase. Perifusion of single islet microtissues produces a higher peak secretion rate, higher secretion during the first and second phases of insulin release, as well as more defined pulsations during the second phase in comparison to perifusion of pooled islets. The developed platform enables to study compound effects on both phases of insulin secretion as shown with two classes of insulin secretagogs. It provides a new tool for studying physiologically relevant dynamic insulin secretion at comparably low sample-to-sample variation and high temporal resolution.

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.

Glycosylated haemoglobin (A1c) best values for type 2 diabetes in the battlefield much ado about nothing? (apparently)

Despite intensive research, therapy of diabetes mellitus type 2 (T2DM) is far from be effective. The most important unresolved issue is to establish a safe glycosylated hemoglobin C (A1c) value well balanced between benefit and side effects. As a result different guidelines suggest different A1c targets generating confusion for patients and clinicians. Here we report two observations which might support a relaxed A1c as suggested by American college of physician (ACP).

Different surgical approaches in laparoscopic sleeve gastrectomy and their influence on metabolic syndrome: A retrospective study

Obesity is a growing health, social, and economic issue and became an epidemic, according to recent report of World Health Organization.The only method with scientifically proved efficiency of body mass loss is a surgical treatment. Laparoscopic sleeve gastrectomy (LSG) is recently a leading method in metabolic surgery. There are no standards of operative technique for LSG so far. The influence of technique modification on metabolic effect has not been described clearly.The aim of this study was to evaluate metabolic effects in patients with morbid obesity who underwent various surgical approaches of LSG.The study included 120 patients who were randomly divided into 3 groups: Group I, where bougie size was 32 French (Fr), Group II-36 Fr and Group III-40 Fr. Each group was divided into 2 subgroups, based on the distance of resection beginning from the pylorus-2 or 6 cm. Statistical analysis of: body mass index (BMI), the Percentage of Excess Weight Loss (%EWL), the Percentage of Excess BMI Loss (%EBMIL), levels of glucose and insulin on an empty stomach, glycated hemoglobin (HbA1c), insulin resistance (Homeostatic Model Assessment of Insulin Resistance Index-HOMA-IR), aspartate transaminase (AST), alanine transaminase (ALT), total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), triglycerides (TG), and C-reactive protein (CRP) were under investigation.Statistically significant decrease in body mass, BMI, %EWL, %EBL, glucose, and insulin concentrations has been observed in all studied groups. It was the highest when the smallest calibration tube has been used (32 Fr). Similar results were observed in HOMA-IR and HbA1c levels. Statistically significant decrease of total cholesterol, LDL, and TG concentrations have been observed. Significant increase of HDL in every group has been also noted. Postoperative CRP values were the lowest when the smallest bougie was used.LSG is effective method of obesity treatment. Metabolic effects of LSG are the most noticeable when a small bougie size is used.

Time to Glycemic Control - an Observational Study of 3 Different Operations

BACKGROUND

Medical treatment fails to provide adequate control for many obese patients with type 2 diabetes mellitus (T2DM). A comparative observational study of bariatric procedures was performed to investigate the time at which patients achieve glycemic control within the first 30 postoperative days following sleeve gastrectomy (SG), mini-gastric bypass (MGB), and diverted sleeve gastrectomy with ileal transposition (DSIT).

METHODS

Included patients had a body mass index (BMI) ≥30 kg/m²; T2DM for ≥3 years, HbA_1C > 7 % for ≥3 months, and no significant weight change (>3 %) within the prior 3 months. Surgical procedures performed were SG (n = 49), MGB (n = 93), and DSIT (n = 109). The primary endpoint was the day within the first postoperative month on which mean fasting capillary glucose levels reached <126 mg/dL. Multivariate logistic regression analysis was used to identify predictors of glycemic control.

RESULTS

The cohort included 251 patients with a mean BMI of 36.04 ± 5.76 kg/m²; age, 52.84 ± 8.52 years; T2DM duration, 13.09 ± 7.54 years; HbA_1C, 8.82 ± 1.58 %. On the morning of surgery, mean fasting plasma glucose was 177.63 ± 51.3 mg/dL; on day 30, 131.35 ± 28.7 mg/dL (p < 0.05). Mean fasting plasma glucose of <126 mg/dL was reached in the DSIT group (124.36 ± 20.21 mg/dL) on day 29, and in the MGB group (123.61 ± 22.51 mg/dL), on day 30. The SG group did not achieve target mean capillary glucose level within postoperative 30 days.

CONCLUSION

During the first postoperative month, glycemic control (<126 mg/dL) was achieved following DSIT and MGB, but not SG. Preoperative BMI and postprandial C-peptide levels were independent predictors of early glycemic control following DSIT.

High baseline C-reactive protein levels predict partial type 2 diabetes mellitus remission after biliopancreatic diversion

BACKGROUND AND AIMS

Several studies demonstrated that surgery can improve inflammation parameters, such as C-reactive protein (CRP). Few biomarkers have been investigated to potentially predict type 2 diabetes mellitus (T2DM) remission. We aimed at determining whether pre-surgery serum CRP levels could predict T2DM remission after 3 years in patients undergoing bariatric surgery, especially biliopancreatic diversion (BPD).

METHODS AND RESULTS

This study was conducted from 2007 to 2009 at the Surgical Department of the University of Genoa, Italy. Forty-four patients with T2DM undergoing BPD (n = 38) or Roux-en-Y gastric bypass (n = 6) were enrolled. The primary endpoint was to evaluate whether pre-surgery CRP levels could predict T2DM partial remission at 3-year follow-up. Secondary endpoints were to assess whether glycaemic, lipid, and inflammatory parameters modified during the follow-up. At baseline, patients with T2DM ranged from overweight to morbid obesity, had mild dyslipidaemia, and a low-grade inflammation. Bariatric surgery improved body weight, lipid and glycaemic profile both at 1- and 3-year follow-up. Pre-surgery CRP levels progressively decreased at 1- and 3-year follow-up. Among inflammatory pre-surgery parameters, only high CRP levels were shown to predict T2DM partial remission after 3 years. Multivariate analysis confirmed the predictive value of pre-surgery CRP levels independently of age, gender, type of surgery, and body mass index.

CONCLUSION

Bariatric surgery, in particular BPD, improved both metabolic and inflammatory biomarkers at 1- and 3-year follow-up. Pre-surgery high CRP levels predicted 3-year T2DM partial remission, indicating a promising target population to be especially treated with BPD.

Changes of insulin sensitivity and secretion after bariatric/metabolic surgery

Type 2 diabetes (T2D) is classically characterized by failure of pancreatic β-cell function and insulin secretion to compensate for a prevailing level of insulin resistance, typically associated with visceral obesity. Although this is usually a chronic, progressive disease in which delay of end-organ complications is the primary therapeutic goal for medical and behavioral approaches, several types of bariatric surgery, especially those that include intestinal bypass components, exert powerful antidiabetes effects to yield remission of T2D in most cases. It has become increasingly clear that in addition to the known benefits of acute caloric restriction and chronic weight loss to ameliorate T2D, bariatric/metabolic operations also engage a variety of weight-independent mechanisms to improve glucose homeostasis, enhancing insulin sensitivity and secretion to varying degrees depending on the specific operation. In this paper, we review the effects of Roux-en-Y gastric bypass, biliopancreatic diversion, and vertical sleeve gastrectomy on the primary determinants of glucose homeostasis: insulin sensitivity, insulin secretion, and, to the lesser extent that it is known, insulin-independent glucose disposal. A full understanding of these effects should help optimize surgical and device-based designs to provide maximal antidiabetes impact, and it holds the promise to identify targets for possible novel diabetes pharmacotherapeutics. These insights also contribute to the conceptual rationale for use of bariatric operations as "metabolic surgery," employed primarily to treat T2D, including among patients not obese enough to qualify for surgery based on traditional criteria related to high body mass index.

European Guidelines for Obesity Management in Adults

Obesity is a chronic metabolic disease characterised by an increase of body fat stores. It is a gateway to ill health, and it has become one of the leading causes of disability and death, affecting not only adults but also children and adolescents worldwide. In clinical practice, the body fatness is estimated by BMI, and the accumulation of intra-abdominal fat (marker for higher metabolic and cardiovascular disease risk) can be assessed by waist circumference. Complex interactions between biological, behavioural, social and environmental factors are involved in regulation of energy balance and fat stores. A comprehensive history, physical examination and laboratory assessment relevant to the patient's obesity should be obtained. Appropriate goals of weight management emphasise realistic weight loss to achieve a reduction in health risks and should include promotion of weight loss, maintenance and prevention of weight regain. Management of co-morbidities and improving quality of life of obese patients are also included in treatment aims. Balanced hypocaloric diets result in clinically meaningful weight loss regardless of which macronutrients they emphasise. Aerobic training is the optimal mode of exercise for reducing fat mass while a programme including resistance training is needed for increasing lean mass in middle-aged and overweight/obese individuals. Cognitive behavioural therapy directly addresses behaviours that require change for successful weight loss and weight loss maintenance. Pharmacotherapy can help patients to maintain compliance and ameliorate obesity-related health risks. Surgery is the most effective treatment for morbid obesity in terms of long-term weight loss. A comprehensive obesity management can only be accomplished by a multidisciplinary obesity management team. We conclude that physicians have a responsibility to recognise obesity as a disease and help obese patients with appropriate prevention and treatment. Treatment should be based on good clinical care, and evidence-based interventions; should focus on realistic goals and lifelong multidisciplinary management.

Impaired increase of plasma abscisic Acid in response to oral glucose load in type 2 diabetes and in gestational diabetes

The plant hormone abscisic acid (ABA) is present and active in humans, regulating glucose homeostasis. In normal glucose tolerant (NGT) human subjects, plasma ABA (ABAp) increases 5-fold after an oral glucose load. The aim of this study was to assess the effect of an oral glucose load on ABAp in type 2 diabetes (T2D) subjects. We chose two sub-groups of patients who underwent an oral glucose load for diagnostic purposes: i) 9 treatment-naive T2D subjects, and ii) 9 pregnant women with gestational diabetes (GDM), who underwent the glucose load before and 8–12 weeks after childbirth. Each group was compared with matched NGT controls. The increase of ABAp in response to glucose was found to be abrogated in T2D patients compared to NGT controls. A similar result was observed in the women with GDM compared to pregnant NGT controls; 8–12 weeks after childbirth, however, fasting ABAp and ABAp response to glucose were restored to normal in the GDM subjects, along with glucose tolerance. We also retrospectively compared fasting ABAp before and after bilio-pancreatic diversion (BPD) in obese, but not diabetic subjects, and in obese T2D patients, in which BPD resulted in the resolution of diabetes. Compared to pre-BPD values, basal ABAp significantly increased 1 month after BPD in T2D as well as in NGT subjects, in parallel with a reduction of fasting plasma glucose. These results indicate an impaired hyperglycemia-induced ABAp increase in T2D and in GDM and suggest a beneficial effect of elevated ABAp on glycemic control.

Interdisciplinary European guidelines on metabolic and bariatric surgery

In 2012, an expert panel composed of presidents of each of the societies, the European Chapter of the International Federation for the Surgery of Obesity (IFSO-EC), and of the European Association for the Study of Obesity (EASO), as well as of the chair of EASO Obesity Management Task Force (EASO OMTF) and other key representatives from IFSO-EC and EASO, devoted the joint Medico-Surgical Workshop of both institutions to the topic of metabolic surgery in advance of the 2013 European Congress on Obesity held in Liverpool. This meeting was prompted by the extraordinary advancement made in the field of metabolic and bariatric surgery during the past decade. It was agreed to revise and update the 2008 Interdisciplinary European Guidelines on Surgery of Severe Obesity produced by focusing in particular on the evidence gathered in relation to the effects on diabetes and the changes in the recommendations of patient eligibility criteria. The expert panel allowed the coverage of key disciplines in the comprehensive management of obesity and obesity-associated diseases, aimed specifically at updating the clinical guidelines to reflect current knowledge, expertise and evidence-based data on metabolic and bariatric surgery.

β-Cell function improvements in grade I/II obese subjects with type 2 diabetes 1 month after biliopancreatic diversion: results from modeling analyses of oral glucose tolerance tests and hyperglycemic clamp studies

OBJECTIVE

To investigate the effect of biliopancreatic diversion (BPD) surgery on β-cell function in grade I and II obese patients with type 2 diabetes using oral and intravenous glucose loads.

RESEARCH DESIGN AND METHODS

Sixty-eight women were divided into the following three groups: 19 lean-control (23.0 ± 2.2 kg/m(2)) and 18 obese-control (35.0 ± 4.8 kg/m(2)) subjects with normal glucose tolerance, and 31 obese patients with type 2 diabetes (36.3 ± 3.7 kg/m(2)). Of the 31 diabetic women, 64% underwent BPD (n = 20, BMI: 36.5 ± 3.7 kg/m(2)) and were reassessed 1 month after surgery. Oral glucose tolerance tests and hyperglycemic clamps were performed. Mathematical modeling was used to analyze basal and stimulated β-cell function, insulin sensitivity (IS), hepatic extraction (HE) of insulin, and delay time of β-cell response to a specific plasma glucose concentration.

RESULTS

After BPD, restoration of the basal disposition index (P < 0.001) and improvement of the stimulated disposition indices in oral and intravenous glucose stimulation of the β-cell were observed (P < 0.05). In both dynamic tests, there were no changes in the delay time of β-cell response. IS for oral glucose stimulation (IS(oral)) and intravenous clamp glucose stimulation (IS(clamp)) was completely normalized (P < 0.001). IS(oral) and IS(clamp) increased approximately 5.0-fold and 3.5-fold, respectively (P < 0.01). The HE of insulin increased in the basal (P < 0.05) and stimulated states (P < 0.01).

CONCLUSIONS

β-Cell function, IS, and HE of insulin improved after BPD, which improved glycemic control.

Clinical practice guidelines for the perioperative nutritional, metabolic, and nonsurgical support of the bariatric surgery patient--2013 update: cosponsored by American Association of Clinical Endocrinologists, The Obesity Society, and American Society for Metabolic & Bariatric Surgery

The development of these updated guidelines was commissioned by the AACE, TOS, and ASMBS Board of Directors and adheres to the AACE 2010 protocol for standardized production of clinical practice guidelines (CPG). Each recommendation was re-evaluated and updated based on the evidence and subjective factors per protocol. Examples of expanded topics in this update include: the roles of sleeve gastrectomy, bariatric surgery in patients with type-2 diabetes, bariatric surgery for patients with mild obesity, copper deficiency, informed consent, and behavioral issues. There are 74 recommendations (of which 56 are revised and 2 are new) in this 2013 update, compared with 164 original recommendations in 2008. There are 403 citations, of which 33 (8.2%) are EL 1, 131 (32.5%) are EL 2, 170 (42.2%) are EL 3, and 69 (17.1%) are EL 4. There is a relatively high proportion (40.4%) of strong (EL 1 and 2) studies, compared with only 16.5% in the 2008 AACE-TOS-ASMBS CPG. These updated guidelines reflect recent additions to the evidence base. Bariatric surgery remains a safe and effective intervention for select patients with obesity. A team approach to perioperative care is mandatory with special attention to nutritional and metabolic issues.

Clinical practice guidelines for the perioperative nutritional, metabolic, and nonsurgical support of the bariatric surgery patient--2013 update: cosponsored by American Association of Clinical Endocrinologists, the Obesity Society, and American Society for Metabolic & Bariatric Surgery

The development of these updated guidelines was commissioned by the AACE, TOS, and ASMBS Board of Directors and adheres to the AACE 2010 protocol for standardized production of clinical practice guidelines (CPG). Each recommendation was re-evaluated and updated based on the evidence and subjective factors per protocol. Examples of expanded topics in this update include: the roles of sleeve gastrectomy, bariatric surgery in patients with type-2 diabetes, bariatric surgery for patients with mild obesity, copper deficiency, informed consent, and behavioral issues. There are 74 recommendations (of which 56 are revised and 2 are new) in this 2013 update, compared with 164 original recommendations in 2008. There are 403 citations, of which 33 (8.2%) are EL 1, 131 (32.5%) are EL 2, 170 (42.2%) are EL 3, and 69 (17.1%) are EL 4. There is a relatively high proportion (40.4%) of strong (EL 1 and 2) studies, compared with only 16.5% in the 2008 AACE-TOS-ASMBS CPG. These updated guidelines reflect recent additions to the evidence base. Bariatric surgery remains a safe and effective intervention for select patients with obesity. A team approach to perioperative care is mandatory with special attention to nutritional and metabolic issues.

Clinical practice guidelines for the perioperative nutritional, metabolic, and nonsurgical support of the bariatric surgery patient--2013 update: cosponsored by American Association of Clinical Endocrinologists, the Obesity Society, and American Society for Metabolic & Bariatric Surgery

The development of these updated guidelines was commissioned by the AACE, TOS, and ASMBS Board of Directors and adheres to the AACE 2010 protocol for standardized production of clinical practice guidelines (CPG). Each recommendation was re-evaluated and updated based on the evidence and subjective factors per protocol. Examples of expanded topics in this update include: the roles of sleeve gastrectomy, bariatric surgery in patients with type-2 diabetes, bariatric surgery for patients with mild obesity, copper deficiency, informed consent, and behavioral issues. There are 74 recommendations (of which 56 are revised and 2 are new) in this 2013 update, compared with 164 original recommendations in 2008. There are 403 citations, of which 33 (8.2%) are EL 1, 131 (32.5%) are EL 2, 170 (42.2%) are EL 3, and 69 (17.1%) are EL 4. There is a relatively high proportion (40.4%) of strong (EL 1 and 2) studies, compared with only 16.5% in the 2008 AACE-TOS-ASMBS CPG. These updated guidelines reflect recent additions to the evidence base. Bariatric surgery remains a safe and effective intervention for select patients with obesity. A team approach to perioperative care is mandatory with special attention to nutritional and metabolic issues.

Interdisciplinary European Guidelines on metabolic and bariatric surgery

In 2012, an outstanding expert panel derived from IFSO-EC (International Federation for the Surgery of Obesity-European Chapter) and EASO (European Association for the Study of Obesity), composed by key representatives of both Societies including past and present presidents together with EASO's OMTF (Obesity Management Task Force) chair, agreed to devote the joint Medico-Surgical Workshop of both institutions to the topic of metabolic surgery as a pre-satellite of the 2013 European Congress on Obesity (ECO) to be held in Liverpool given the extraordinarily advancement made specifically in this field during the past years. It was further agreed to revise and update the 2008 Interdisciplinary European Guidelines on Surgery of Severe Obesity produced in cooperation of both Societies by focusing in particular on the evidence gathered in relation to the effects on diabetes during this lustrum and the subsequent changes that have taken place in patient eligibility criteria. The expert panel composition allowed the coverage of key disciplines in the comprehensive management of obesity and obesity-associated diseases, aimed specifically at updating the clinical guidelines to reflect current knowledge, expertise and evidence-based data on metabolic and bariatric surgery.

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.

Bariatric surgery and T2DM improvement mechanisms: a mathematical model

Background

Consensus exists that several bariatric surgery procedures produce a rapid improvement of glucose homeostasis in obese diabetic patients, improvement apparently uncorrelated with the degree of eventual weight loss after surgery. Several hypotheses have been suggested to account for these results: among these, the anti-incretin, the ghrelin and the lower-intestinal dumping hypotheses have been discussed in the literature. Since no clear-cut experimental results are so far available to confirm or disprove any of these hypotheses, in the present work a mathematical model of the glucose-insulin-incretin system has been built, capable of expressing these three postulated mechanisms. The model has been populated with critically evaluated parameter values from the literature, and simulations under the three scenarios have been compared.

Results

The modeling results seem to indicate that the suppression of ghrelin release is unlikely to determine major changes in short-term glucose control. The possible existence of an anti-incretin hormone would be supported if an experimental increase of GIP concentrations were evident post-surgery. Given that, on the contrary, collected evidence suggests that GIP concentrations decrease post-surgery, the lower-intestinal dumping hypothesis would seem to describe the mechanism most likely to produce the observed normalization of Type 2 Diabetes Mellitus (T2DM) after bariatric surgery.

Conclusions

The proposed model can help discriminate among competing hypotheses in a context where definitive data are not available and mechanisms are still not clear.

Type 2 diabetes mellitus: a possible surgically reversible intestinal dysfunction

Type 2 diabetes mellitus (T2DM) is a global public health problem often associated with obesity. Bariatric surgery is effective for treating serious obesity, and techniques involving intestinal bypass have metabolic benefits, such as complete and early remission of T2DM. We present a literature review of the possible mechanisms of early normalization of glycemic homeostasis after bariatric surgery, including intestinal gluconeogenesis, increased antidiabetogenic signals from L cells located in the distal small intestine, and impaired secretion of diabetogenic signals in the upper part of the small intestine. Adding to these potential mechanisms, unknown factors that regulate insulin sensitivity may be involved and altered by bariatric surgery. This review discusses the various hypotheses about the mechanisms of glycemic control after bariatric surgery involving intestinal bypass. Further research is essential to better understand these mechanisms and to identify potential new mechanisms that might help in developing less invasive and safer alternatives for the treatment of T2DM and reveal novel pharmaceutical targets for glycemic control.

Insulin resistance and bariatric surgery

The objective of this article is to systematically review the changes in insulin resistance after various types of bariatric surgical procedures. A Pubmed and EMBASE search for studies measuring insulin resistance before and after bariatric surgery was done and all original research articles from 1980 to present (2011) were included. Only the currently widely performed bariatric procedures were included. A meta-analysis of change in HOMA-IR was conducted, grouping studies with similar duration of follow-up. The percentage decrease in HOMA-IR at <=2 weeks, 1 month, 3 months, 6 months, 12 months and >16-18 months was found to be (mean ± standard error) -33.48 ± 5.78, -46.43 ± 6.99, -38.79 ± 9.64, -58.62 ± 7.38, -44.91 ± 7.98 and -67.04 ± 10.78%, respectively. RYGB (gastric bypass) and BPD (biliopancreatic diversion) produced a significant decrease in insulin resistance at 2 weeks after surgery, while LSG (sleeve gastrectomy) was strongly trending. LSG produced an earlier decrease in insulin resistance when compared to LAGB (gastric banding). RYGB, BPD and LSG produce an early decrease in insulin resistance through yet unknown mechanisms.

Very-low-calorie diet: a quick therapeutic tool to improve β cell function in morbidly obese patients with type 2 diabetes

BACKGROUND

Caloric restriction in obese diabetic patients quickly improves glucose control, independently from weight loss. However, the early effects of a very-low-calorie diet (VLCD) on insulin sensitivity and insulin secretion in morbidly obese patients with type 2 diabetes are still unclear.

OBJECTIVE

The objective was to study the relative contributions of insulin sensitivity, insulin secretion, or both to improvement in glucose metabolism, after 1 wk of caloric restriction, in severely obese diabetic patients.

DESIGN

Hyperglycemic clamps were performed in 14 severely obese (BMI, in kg/m(2): >40) patients with type 2 diabetes in good glucose control (glycated hemoglobin < 7.5%) before and after 7 d of a VLCD (400 kcal/d).

RESULTS

The VLCD caused a 3.22 ± 0.56% weight loss (P < 0.001), 42.0% of which was fat loss, accompanied by decreases in fasting plasma glucose (P < 0.05) and triglycerides (P < 0.01). In parallel, the Disposition Index, which measures the body's capability to dispose of a glucose load, increased from 59.0 ± 6.3 to 75.5 ± 6.3 mL· min(-1) · m(-2) body surface area (P < 0.01), because of improvements in indexes of both first- and second-phase insulin secretion (P < 0.02), but with no changes in insulin sensitivity (P = 0.33).

CONCLUSION

The marked improvement in metabolic profile, observed in severely obese patients with type 2 diabetes after a 7-d VLCD, was primarily due to the amelioration of β cell function, whereas no contribution of insulin sensitivity was shown. This trial was registered at www.clinicaltrials.gov as NCT01447524.

The effects of biliopancreatic diversion on type 2 diabetes mellitus in patients with mild obesity (BMI 30-35 kg/m2) and simple overweight (BMI 25-30 kg/m2): a prospective controlled study

BACKGROUND

Beneficial effects of BPD on T2DM in BMI >35 kg/m(2) patients are far better than those in patients with BMI 25-35. This study was aimed at investigating if a similar difference exists between patients with mild obesity (OB, BMI 30-35) or simple overweight (OW, BMI 25-30).

METHODS

Fifteen OB (six M) and 15 OW (13 M), diabetic for ≥ 3 years, with HbA1c ≥ 7.5% despite medical therapy, underwent BPD. OB/OW: age 55.1 ± 8.0/57.8 ± 6.7 years, BMI 33.1 ± 1.5/28.0 ± 1.3 kg/m(2), diabetes duration 11.6 ± 8.0/11.1 ± 6.1 years, insulin therapy 4/8 p. FSG and HbA1c were determined preoperatively and up to 2 years. Insulin resistance and beta-cell function were explored by means of HOMA-IR and IVGTT (AIR). Thirty-eight diabetic patients on medical therapy served as controls.

RESULTS

Mean BMI stabilized around 27 since the 4th month in OB, and 24 since 1st month in OW. FSG in OB/OW preop, 1, 12, 24 months: 234 ± 76/206 ± 62 mg/dL, 154 ± 49/176 ± 75, 131 ± 32/167 ± 48, 134 ± 41/154 ± 41 (cross-sectional n.s. at all times); HbA1c: 9.5 ± 1.6/9.1 ± 1.3, 7.3 ± 1.1/7.3 ± 1.2, 5.9 ± 0.6/7.1 ± 1.1 (p < 0.01), 5.9 ± 0.9/6.9 ± 1.1 (p < 0.01). HOMA-IR, preoperatively 10.7 ± 5.8/7.5 ± 5.4, went below 3.0 at 1 month and remained such until 2 years in both groups. AIR, preoperatively 1.11 ± 3.17/1.27 ± 2.68 μIU/mL, in OB significantly increased at 4 months to 7.63 ± 5.79, maintained up to 2 years with 6.95 ± 3.19, whereas in OW, statistical significance was reached only at 2 years with 5.02 ± 4.87.

CONCLUSIONS

Significantly different BPD effect, thus biological severity of T2DM, also exists between mildly obese and simply overweight patients. The rise of AIR allows hoping that an increase of beta-cell mass may occur in the long run.

Body weight at developmental age in siblings born to mothers before and after surgically induced weight loss

BACKGROUND

To gain insight into the role of epigenetic factors in determining body weight in adolescence, we studied the body weight of siblings born to the same mother before and after biliopancreatic diversion (BPD) for obesity. The study was performed in a university hospital during a 20-year period.

METHODS

The siblings born before and after BPD were retrospectively rated by their mother as normal, overweight, or obese at 1, 6, and 12 years.

RESULTS

At 1 and 6 years, the body weight was rated as similar in the subsets. However, at 12 years of age, a greater percentage of those born before BPD were considered overweight (42% versus 33%) and obese (22% versus 3%; P <.009) than their counterparts born after BPD. Considering only the subjects aged 21-25 years at the study period, the body weight and body mass index in subjects born before BPD were greater (P <.02 and P <.012, respectively) than in those born after BPD (79.5 ± 16.5 kg versus 66.7 ± 11.8 kg, and 27.5 ± 3.9 kg/m(2) versus 23.4 ± 3.7 kg/m(2), respectively).

CONCLUSION

The results of the present study, in which the influences of the genetic pattern and environmental and educational factors were minimized, show that adolescents born to post-BPD mothers weigh less than their siblings born to the same mother before BPD when she was still obese. An insulin-resistant milieu during pregnancy could account for the greater body weight later in adolescence.

First-phase insulin secretion, insulin sensitivity, ghrelin, GLP-1, and PYY changes 72 h after sleeve gastrectomy in obese diabetic patients: the gastric hypothesis

BACKGROUND

The aim of this study was to evaluate the possible role of sleeve gastrectomy (SG) per se in the reversibility of diabetes.

METHODS

Insulin secretion and peripheral insulin sensitivity using the intravenous glucose tolerance test (IVGTT) were assessed in 18 obese type 2 diabetic patients and in 10 nondiabetic obese patients before and 3 days after SG, before any food intake and any weight change occurrence. At the same time, ghrelin, GLP-1, and PYY levels were determined.

RESULTS

In diabetic patients who had the disease less than 10.5 years, the first phase of insulin secretion promptly improved after SG. The early insulin area under the curve (AUC) significantly increased at the postoperative IVGTT, indicating an increased glucose-induced insulin secretion. The second phase of insulin secretion (late AUC) significantly decreased after SG in all groups, indicating an improved insulin peripheral sensitivity. In all groups, pre- and postoperatively, intravenous glucose stimulation determined a decrease in ghrelin values and an increase in GLP-1 and PYY values. However, in the group of patients with disease duration >10.5 years, the differences were not significant except for the late insulin AUC. Postoperative basal and intravenous glucose-stimulated ghrelin levels were lower than preoperative levels in all groups of patients. Basal and intravenous stimulated GLP-1 and PYY postoperative values were higher than preoperative levels in all groups.

CONCLUSIONS

Restoration of the first phase of insulin secretion and improved insulin sensitivity in diabetic obese patients immediately after SG, before any food passage through the gastrointestinal tract and before any weight loss, seem to be related to ghrelin, GLP-1, and PYY hormonal changes of possible gastric origin and was neither meal- nor weight-change-related. Duration of the disease up to 10.5 years seems to be a major cut off in the pathophysiological changes induced by SG. A "gastric" hypothesis may be put forward to explain the antidiabetes effect of SG.

Improvement in ß-cell function in patients with normal and hyperglycemia following Roux-en-Y gastric bypass surgery

Glycemic disorders resolve following Roux-en-Y gastric bypass (RYGB) surgery, but early and longer-term mechanisms regarding effects on β-cell dysfunction as well as relationships with decreasing adiposity are not well understood. We evaluated longitudinal changes in peripheral insulin sensitivity (Si), the acute insulin response to glucose (AIRg), and the composite estimate of β-cell function, the disposition index (DI), over 24 mo via frequently sampled intravenous glucose tolerance testing in severely obese women who had fasting normoglycemia (n = 16) and hyperglycemia (n = 11) before RYGB surgery; homeostatic model assessment (HOMA-IR) estimated insulin resistance; air displacement plethysmography determined adipose tissue mass. At baseline, subjects with normoglycemia had adequate DI associated with elevated AIRg, but DI was markedly reduced in subjects with hyperglycemia. Within 1-6 mo post-RYGB, glycemic control was normalized in subjects with hyperglycemia related to reduced HOMA-IR (-54% at 1 mo, P < 0.005) and increased DI (23-fold at 6 mo vs. baseline, P < 0.05). Over 24 mo, DI improved in subjects with hyperglycemia (15-fold vs. baseline, P < 0.005) and also modestly in subjects with normoglycemia (58%, P < 0.05), due largely to increased Si. Decreasing adiposity correlated with longer-term HOMA-IR and Si values at 6 and 24 mo, respectively. In patients exhibiting fasting hyperglycemia before surgery, β-cell function improved early following RYGB, due largely to increases in insulin secretion. For both normoglycemic and hyperglycemic subjects, further improvement or stabilization of β-cell function over the 2 yr is due largely to improved Si associated with reduced adiposity.

Resolution of type 2 diabetes following bariatric surgery: implications for adults and adolescents

Bariatric surgery is now widely reported to ameliorate or resolve type 2 diabetes mellitus in adults. Some clinical investigators even suggest its use as an early therapeutic intervention for type 2 diabetes in patients not meeting standard criteria for bariatric surgery. However, little is known about the exact mechanisms explaining the metabolic consequences, and much active investigation is underway to identify hormonal changes leading to diabetes resolution. This review includes a detailed description of various bariatric surgical procedures, including the latest less-invasive techniques, and a summary of current data providing insight into the short- and long-term metabolic effects. We outline current hypotheses regarding the mechanisms by which these surgical procedures affect diabetes and report on morbidity and mortality. Finally, we discuss the available data on bariatric surgery in adolescent patients, including special considerations in this potentially vulnerable population.

Beta-cell function improvement after biliopancreatic diversion in subjects with type 2 diabetes and morbid obesity

In subjects with obesity and type 2 diabetes mellitus (T2DM), biliopancreatic diversion (BPD) improves glucose stimulated insulin secretion, whereas the effects on other secretion mechanisms are still unknown. Our objective was to evaluate the early effects of BPD on nonglucose-stimulated insulin secretion. In 16 morbid obese subjects (9 with T2DM and 7 with normal fasting glucose (NFG)), we measured insulin secretion after glucose-dependent arginine stimulation test and after intravenous glucose tolerance test (IVGTT) before and 1 month after BPD. After surgery the mean weight lost was 13% in both groups. The acute insulin response during IVGTT was improved in T2DM after BDP (from 55 +/- 10 to 277 +/- 91 pmol/l, P = 0.03). A reduction of insulin response to arginine was observed in NFG, whereas opposite was found in T2DM. In particular, acute insulin response to arginine at basal glucose concentrations (AIR(basal)) was reduced but insulin response at 14 mmol/l of plasma glucose (AIR(14)) was increased. Therefore, after BPD any statistical difference in AIR(14) between NFG and T2DM disappeared (1,032 +/- 123 for NFG and 665 +/- 236 pmol/l for T2DM, P = ns). The same was observed for Slope(AIR), a measure of glucose potentiation, reduced in T2DM before BPD but increased after surgery, when no statistically significant difference resulted compared with NFG (Slope(AIR) after BPD: 78 +/- 11 in NFG and 56 +/- 18 pmol/l in T2DM, P = ns). In conclusion, in obese T2DM subjects 1 month after BPD we observed a great improvement of both glucose- and nonglucose-stimulated insulin secretions. The mechanisms by which BDP improve insulin secretion are still unknown.

Mechanisms of early improvement/resolution of type 2 diabetes after bariatric surgery

Bariatric surgery represents the main option for obtaining substantial and long-term weight loss in morbidly obese subjects. In addition, malabsorptive (biliopancreatic diversion, BPD) and restrictive (roux-en-Y gastric bypass, RYGB) surgery, originally devised to treat obesity, has also been shown to help diabetes. Indeed, type 2 diabetes is improved or even reversed soon after these operations and well before significant weight loss occurs. Two hypotheses have been proposed to explain the early effects of bariatric surgery on diabetes--namely, the hindgut hypothesis and the foregut hypothesis. The former states that diabetes control results from the more rapid delivery of nutrients to the distal small intestine, thereby enhancing the release of hormones such as glucagon-like peptide-1 (GLP-1). The latter theory contends that exclusion of the proximal small intestine reduces or suppresses the secretion of anti-incretin hormones, leading to improvement of blood glucose control as a consequence. In fact, increased GLP-1 plasma levels stimulate insulin secretion and suppress glucagon secretion, thereby improving glucose metabolism. Recent studies have shown that improved intestinal gluconeogenesis may also be involved in the amelioration of glucose homoeostasis following RYGB. Although no large trials have specifically addressed the effects of bariatric surgery on the remission or reversal of type 2 diabetes independent of weight loss and/or caloric restriction, there are sufficient data in the literature to support the idea that this type of surgery--specifically, RYGB and BPD--can lead to early improvement of glucose control independent of weight loss.

Bariatric surgery: unstressing or boosting the beta-cell?

Bariatric surgery is the most effective therapy for severe obesity in terms of reduction of morbidity and mortality and quality of life improvement. Different bariatric procedures distinctly differ with regard to their effectiveness to reduce body weight and to improve morbidities, such as type 2 diabetes. In this regard, the most effective procedures are bilio-pancreatic diversion (BPD) and duodenal switch procedure curing 98.9% of the diabetes patients, followed by Roux-en-Y gastric bypass (RYGB) with 83.7% success rate, by gastroplasty with 71.6% and by gastric banding with 47.9%. Interestingly, a net improvement up to resolution of type 2 diabetes has been consistently reported few days after RYGB and BPD. RYGB promotes incretin secretion which, in turn, stimulates insulin secretion while insulin sensitivity is slightly improved. Rarely, the long-term effect of incretin hypersecretion might result in hypertrophy and hyperplasia of the islets of Langerhans, otherwise known as nesidioblastosis, associated with hyperinsulinaemia and severe postprandial hypoglycaemia. In contrast, BDP improves insulin resistance to a greater extent and results, in the long run, in supra-normal values of insulin sensitivity with subsequent reduction of insulin secretion. The mechanism allowing diabetes resolution after surgical intestinal manipulation is extremely interesting but only partially understood.

Treating diabetes and prediabetes by focusing on obesity management

Obesity is associated with an increased risk of developing insulin resistance and type 2 diabetes mellitus (T2DM). In obesity, the adipose cell releases nonesterified free fatty acids, hormones, adipocytokines, and other substances that are involved in insulin resistance. Under normal conditions, the pancreatic islet beta cells increase production of insulin sufficiently to maintain normal blood glucose concentrations despite insulin resistance. However, in genetically predisposed patients, the beta cells eventually become dysfunctional and T2DM develops. The development of T2DM can be delayed or sometimes prevented in individuals with obesity who are able to lose weight. Weight loss can be achieved medically with behavioral therapies that combine diet and exercise treatment or with behavioral therapies combined with weight-loss medications or weight-loss surgery. In this article, we summarize the evidence of obesity management in treating T2DM and prediabetes.

Daily glucose profiles in Japanese people with normal glucose tolerance as assessed by continuous glucose monitoring

BACKGROUND

Little information is available regarding glucose fluctuations in postprandial states and during the oral glucose tolerance test (OGTT) in Japanese people with normal glucose tolerance (NGT).

METHODS

Glucose profiles of 27 Japanese people were measured for 4 days by using continuous glucose monitoring. A 75-g OGTT was conducted on the second day, and 24 subjects diagnosed with NGT by a 75-g OGTT were enrolled. The subjects were monitored for their postprandial glucose profile in their ordinary daily life on the third day.

RESULTS

The results of our study have shown that the median time (interquartile range) to maximum glucose levels in OGTT was 38 (25-49) min after glucose load and that the median time to maximum glucose levels after breakfast, lunch, and dinner was 40 (31-75), 50 (30-70), and 45 (36-50) min, respectively. The median increase in glucose during OGTT was 45 (35-66) mg/dL, and that after breakfast, lunch and dinner was 21 (12-32), 37 (27-48), and 44 (25-63) mg/dL, respectively. Those with a higher insulinogenic index reached their maximum glucose levels in a shorter time (r = -0.46, P = 0.025) and had smaller glucose increments during OGTT (r = -0.49, P = 0.014).

CONCLUSIONS

This study is the first report to document the glucose profile of Asian people with NGT.

First-phase insulin secretion restoration and differential response to glucose load depending on the route of administration in type 2 diabetic subjects after bariatric surgery

OBJECTIVE

The purpose of this study was to elucidate the mechanisms of diabetes reversibility after malabsorptive bariatric surgery.

RESEARCH DESIGN AND METHODS

Peripheral insulin sensitivity and beta-cell function after either intravenous (IVGTT) or oral glucose tolerance (OGTT) tests and minimal model analysis were assessed in nine obese, type 2 diabetic subjects before and 1 month after biliopancreatic diversion and compared with those in six normal-weight control subjects. Insulin-dependent whole-body glucose disposal was measured by the euglycemic clamp, and glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) were also measured.

RESULTS

The first phase of insulin secretion after the IVGTT was fully normalized after the operation. The disposition index from OGTT data was increased about 10-fold and became similar to the values found in control subjects, and the disposition index from IVGTT data increased about 3.5-fold, similarly to what happened after the euglycemic clamp. The area under the curve (AUC) for GIP decreased about four times (from 3,000 +/- 816 to 577 +/- 155 pmol x l(-1) x min, P < 0.05). On the contrary, the AUC for GLP1 almost tripled (from 150.4 +/- 24.4 to 424.4 +/- 64.3 pmol x l(-1) . min, P < 0.001). No significant correlation was found between GIP or GLP1 percent changes and modification of the sensitivity indexes independently of the route of glucose administration.

CONCLUSIONS

Restoration of the first-phase insulin secretion and normalization of insulin sensitivity in type 2 diabetic subjects after malabsorptive bariatric surgery seem to be related to the reduction of the effect of some intestinal factor(s) resulting from intestinal bypass.

Do Incretins play a role in the remission of type 2 diabetes after gastric bypass surgery: What are the evidence?

Gastric bypass surgery (GBP), in addition to weight loss, results in dramatic remission of type 2 diabetes (T2DM). The mechanisms by which this remission occurs are unclear. Besides weight loss and caloric restriction, the changes in gut hormones that occur after GBP are increasingly gaining recognition as key players in glucose control. Incretins are gut peptides that stimulate insulin secretion postprandially; the levels of these hormones, particularly glucagon-like peptide-1, increase after GBP in response to nutrient stimulation. Whether these changes are causal to changes in glucose homeostasis remain to be determined. The purpose of this review is to assess the evidence on incretin changes and T2DM remission after GBP, and the possible mechanisms by which these changes occur. Our goals are to provide a thorough update on this field of research so that recommendations for future research and criteria for bariatric surgery can be evaluated.

Pregnancy in formerly type 2 diabetes obese women following biliopancreatic diversion for obesity

BACKGROUND

This study describes the pregnancy of previously obese women with type 2 diabetic who reduced body weight and normalized serum glucose level following biliopancreatic diversion (BPD) for obesity.

METHODS

A subset of ten women who had type 2 diabetes prior to BPD and who developed pregnancy after the operation was retrospectively identified.

RESULTS

All pregnancies were completely normal, and serum glucose levels remained within the physiological range throughout all the pregnancy. These post-diabetic women delivered 13 infants in good health with a normal birth weight and no case of macrosomia.

CONCLUSIONS

These data are a clinical confirmation of the post-BPD improvement of beta-cell response to increased functional demand in obese patients with preoperative type 2 diabetes.

A comparison of a personal series of biliopancreatic diversion and literature data on gastric bypass help to explain the mechanisms of resolution of type 2 diabetes by the two operations

BACKGROUND

Roux-en-Y gastric bypass (RYGBP) and biliopancreatic diversion (BPD) are highly beneficial operations for type 2 diabetes mellitus (T2DM) in obese patients, leading to complete T2DM resolution in 75-90 and 97-99% of cases, respectively. In both RYGBP and BPD, the foregut is excluded from the food stream and the distal small bowel receives the food stimulation, while following BPD fat intestinal absorption is also extremely limited. This study was carried out to identify clinical features that could give insight on the different mechanisms of action on diabetes resolution.

METHODS

The files of 443 severely obese patients with T2DM undergoing BPD from May 1976 to May 2007 were examined, and the presence of T2DM (fasting serum glucose >125 mg/ml) at 1-2 months, at 1 year, at 10 years, and at > or =20 years following the operation was recorded.

RESULTS

The percentage of patients cured (fasting serum glucose reduced to < or =110 mg/dl, on free diet and with no therapy) was 74% at 1 month, 97% at 1 and 10 years, and 91% at > or =20 years, the 26% of uncured patients at 1 month being those with most severe preoperative T2DM.

CONCLUSIONS

As the early results after BPD resemble those reported after RYGBP, it can be hypothesized that the duodenal exclusion and the distal small bowel stimulation are the first mechanisms acting in BPD, immediately after the operation, that only subsequently the myocellular fat depletion, which cannot be immediate, takes over, and that the minimal fat absorption is the mechanism accounting for the long-term results of BPD.