Role of the incretin system in the remission of type 2 diabetes following bariatric surgery

Pyrrhic victory? Long-term results of biliopancreatic diversion on patients with type 2 diabetes and severe obesity

BACKGROUND

The long-term results after biliopancreatic diversion (BPD) in patients with type 2 diabetes (T2D) and severe obesity is still being debated.

OBJECTIVE

Retrospective evaluation of the long-term metabolic and clinical conditions of patients with T2D following BPD.

SETTING

University hospital.

METHODS

A total of 173 patients with T2D and severe obesity were investigated prior to and at 3-5 and 10-20 years after BPD. Anthropometric, biochemical, and clinical findings preoperatively and throughout follow-up were considered. The long-term data were compared with those of a cohort of 173 T2D patients with obesity treated with conventional therapy.

RESULTS

T2D resolved within the first postoperative phases in most patients, and in the long and very long term, the fasting blood glucose level remained above the normal range in only 8% of patients. Likewise, a stable improvement of blood lipid pattern was observed (follow-up rate 63%). In contrast, in nonsurgical patients in the long term, the glucose and lipid metabolic parameters remained in the pathologic range in all cases. In the BPD group, a very high number of severe BPD-related complications was recorded, and 27% of the BPD patients died, whereas in the control group, 87% of patients were still alive at the end of the follow-up period (P < .02).

CONCLUSION

Despite the high T2D stable resolution rate and the normalization of most metabolic data at 10-20 years following surgery, these results indicate that BPD should be indicated with caution in the surgical treatment of T2D in patients with severe obesity.

Identification of Proteins Associated with the Early Restoration of Insulin Sensitivity After Biliopancreatic Diversion

CONTEXT

Insulin resistance (IR) is a risk factor for type 2 diabetes, diabetic kidney disease, cardiovascular disease and nonalcoholic steatohepatitis. Biliopancreatic diversion (BPD) is the most effective form of bariatric surgery for improving insulin sensitivity.

OBJECTIVE

To identify plasma proteins correlating with the early restoration of insulin sensitivity after BPD.

DESIGN

Prospective single-center study including 20 insulin-resistant men with morbid obesity scheduled for BPD. Patient characteristics and blood samples were repeatedly collected from baseline up to 4 weeks postsurgery. IR was assessed by homeostatic model assessment for insulin resistance (HOMA-IR), Matsuda Index, and by studying metabolic profiles during meal tolerance tests. Unbiased proteomic analysis was performed to identify plasma proteins altered by BPD. Detailed plasma profiles were made on a selected set of proteins by targeted multiple reaction monitoring mass spectrometry (MRM/MS). Changes in plasma proteome were evaluated in relation to metabolic and inflammatory changes.

RESULTS

BPD resulted in improved insulin sensitivity and reduced body weight. Proteomic analysis identified 29 proteins that changed following BPD. Changes in plasma levels of afamin, apolipoprotein A-IV (ApoA4), and apolipoprotein A-II (ApoA2) correlated significantly with changes in IR.

CONCLUSION

Circulating levels of afamin, ApoA4, and ApoA2 were associated with and may contribute to the rapid improvement in insulin sensitivity after BPD.

Metabolic Outcomes of Surgery for Non-Obese Type 2 Diabetes

The most plausible contributing factor to non-obese type 2 diabetes may be imbalanced incretin release from the intestinal epithelium in response to nutrients. Rerouting intestinal continuity through bypass surgery to modulate incretin release is therefore a reasonable treatment. We believe that a major determinant of metabolic outcomes is entire duodenal exclusion without leaving any duodenal epithelium and exclusion of sufficient length of jejunum. More importantly, the procedure should be implemented with safety and without sequelae. To achieve this, we invented a novel procedure with acceptable surgical safety and excellent and durable metabolic outcomes. Post-surgical intestinal adaptation should be considered to achieve successful outcomes.

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.

Preserving Duodenal-Jejunal (Foregut) Transit Does Not Impair Glucose Tolerance and Diabetes Remission Following Gastric Bypass in Type 2 Diabetes Sprague-Dawley Rat Model

BACKGROUND

Possible mechanisms underlying diabetes remission following Roux-en-Y gastric bypass (RYGB) include eradication of putative factor(s) with duodenal-jejunal bypass.

OBJECTIVE

The objective of this study is to observe the effects of duodenal-jejunal transit on glucose tolerance and diabetes remission in gastric bypass rat model.

METHOD

In order to verify the effect of duodenal-jejunal transit on glucose tolerance and diabetes remission in gastric bypass, 22 type 2 diabetes Sprague-Dawley rat models established through high-fat diet and low-dose streptozotocin (STZ) administered intraperitoneally were assigned to one of three groups: gastric bypass with duodenal-jejunal transit (GB-DJT n = 8), gastric bypass without duodenal-jejunal transit (RYGB n = 8), and sham (n = 6). Body weight, food intake, blood glucose, as well as meal-stimulated insulin, and incretin hormone responses were assessed to ascertain the effect of surgery in all groups. Oral glucose tolerance test (OGTT) and insulin tolerance test (ITT) were conducted three and 7 weeks after surgery.

RESULTS

Comparing our GB-DJT to the RYGB group, we saw no differences in the mean decline in body weight, food intake, and blood glucose 8 weeks after surgery. GB-DJT group exhibited immediate and sustained glucose control throughout the study. Glucagon-like peptide 1 (GLP-1) and gastric inhibitory polypeptide (GIP) levels were also significantly increased from preoperative level in the GB-DJT group (p < 0.05). Insulin and GLP-1 area under curve (AUC) as well as improved glycemic excursion on OGTT did not differ between GB-DJT and RYGB groups. Outcomes with sham operation did not differ from preoperative level.

CONCLUSION

Preserving duodenal-jejunal transit does not impede glucose tolerance and diabetes remission after gastric bypass in type-2 diabetes Sprague-Dawley rat model.

Cereal fructan extracts alter intestinal fermentation to reduce adiposity and increase mineral retention compared to oligofructose

PURPOSE

Intestinal fermentation of inulin-type fructans, including oligofructose, can modulate adiposity, improve energy regulation, and increase mineral absorption. We aimed to determine whether cereal fructans had greater effects on reducing adiposity and improving mineral absorption compared with oligofructose.

METHODS

Thirty-two male Sprague-Dawley rats were randomly assigned to one of four dietary treatments that contained 0% fructan (control), or 5% fructan provided by oligofructose (OF), a barley grain fraction (BGF), or a wheat stem fraction (WSF). After 1 week on the diets, mineral absorption and retention was assessed. At 4 weeks, blood samples were collected for gut hormone analysis, adipose depots were removed and weighed, and caecal digesta was analyzed for pH and short-chain fatty acids (SCFA).

RESULTS

The BGF and WSF, but not OF, had lower total visceral fat weights than the Control (p < 0.05). The fructan diets all lowered caecal pH and raised caecal digesta weight and total SCFA content, in comparison to the Control. Caecal propionate levels for OF were similar to the Control and higher for WSF (p < 0.05). Plasma peptide YY and glucagon-like peptide-1 levels were elevated for all fructan groups when compared to Control (p < 0.001) and gastric inhibitory peptide was lower for the WSF compared to the other groups (p < 0.05). The fructan diets improved calcium and magnesium retention, which was highest for WSF (p < 0.05). BGF and WSF in comparison to OF showed differential effects on fermentation, gut hormone levels, and adiposity.

CONCLUSIONS

Cereal fructan sources have favorable metabolic effects that suggest greater improvements in energy regulation and mineral status to those reported for oligofructose.

The Effects of One-Anastomosis Gastric Bypass on Glucose Metabolism in Goto-Kakizaki Rats

BACKGROUND

The improvement in glucose metabolism after bariatric surgery is well established. The aim of this study was to investigate the hormones and glycemic control in diabetes after a one-anastomosis gastric bypass (OAGB) variant in an animal model of non-obese type 2 diabetes mellitus.

METHODS

Thirty-six Goto-Kakizaki rats were randomly assigned to undergo one of the following procedures: OAGB (18 rats) or sham intervention (18 rats). Each group was subdivided into three additional groups according to the time of surgery (early-12 weeks; intermediate-16 weeks; and late-20 weeks). Weight, fasting glycemia, glucose tolerance test (OGTT), and hormone levels (glucagon, insulin, glucagon-like peptide-1 [GLP-1], and glucose-dependent insulinotropic peptide [GIP]) were measured.

RESULTS

All rats maintained their weight. The OGTT showed a significant improvement in glycemic levels in rats with OAGB in all time groups (p < 0.002, for all groups at 60 min). Insulin levels decreased significantly in all animals with OAGB, but glucagon levels increased (glucagon paradoxical response). GLP-1 and GIP increased in rats with OAGB at all times, but was only statistically significant in the early surgery group of GLP-1 (p < 0.005).

CONCLUSION

OAGB in a non-obese diabetic rat model improves glycemic control, with a significant decrease in glucose and insulin levels. This reduction without weight loss suggests a surgically induced enhancement of pancreatic function. It appears that this improvement occurs, although the GLP-1 levels were significantly increased only in the early stages. The paradoxical response of glucagon should be further evaluated.

Weight Regain After Gastric Bypass: Influence of Gut Hormones

BACKGROUND

The Roux-en-Y gastric bypass (RYGB) is the gold standard bariatric operation. However, a major concern in late follow-up is the substantial weight regain. Understanding the role of gastrointestinal hormone secretion in this situation is relevant.

METHODS

The aim of the present study was to evaluate the influence of gastrointestinal hormones comparing postprandial secretion of ghrelin, glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide 1 (GLP-1), and leptin between patients with weight regain and those with favorable weight control. Twenty-four patients with follow-up from 27 to 59 months were divided into two groups according to sustained weight loss: group A (14 patients) had sustained weight losses, and group B (10 patients) had significant weight regain. Basal serum levels of ghrelin, GIP, GLP-1, and leptin after fasting and 30, 60, 90, and 120 min after a standard meal were measured.

RESULTS

There was no difference in the ghrelin secretion. There was a difference in the GIP secretion, with a higher percentage increase in 30 min in group A (330% × 192.2%; p = 0.01). There were also differences in the GLP-1 secretion, with higher increases in absolute (p = 0.03) and percentage values after 30 min in group A (124% × 46.5%; p = 0.01). There was also a difference between baseline leptin values, with higher levels in group B (p = 0.02).

CONCLUSIONS

The secretion of gut hormones in patients with weight regain after RYGB is different from that in patients with satisfactory weight outcome. After meal stimulation, reduced levels of GIP and GLP-1 may indicate the influence of gut hormones in the process of weight regain.

Metabolic Mechanisms in Obesity and Type 2 Diabetes: Insights from Bariatric/Metabolic Surgery

Obesity and the related diabetes epidemics represent a real concern worldwide. Bariatric/metabolic surgery emerged in last years as a valuable therapeutic option for obesity and related diseases, including type 2 diabetes mellitus (T2DM). The complicated network of mechanisms involved in obesity and T2DM have not completely defined yet. There is still a debate on which would be the first metabolic defect leading to metabolic deterioration: insulin resistance or hyperinsulinemia? Insight into the metabolic effects of bariatric/metabolic surgery has revealed that, beyond weight loss and food restriction, other mechanisms can be activated by the rearrangements of the gastrointestinal tract, such as the incretinic/anti-incretinic system, changes in bile acid composition and flow, and modifications of gut microbiota; all of them possibly involved in the remission of T2DM. The complete elucidation of these mechanisms will lead to a better understanding of the pathogenesis of this disease. Our aim was to review some of the metabolic mechanisms involved in the development of T2DM in obese patients as well as in the remission of this condition in patients submitted to bariatric/metabolic surgery.

Lipopolysaccharide and lipopolysaccharide-binding protein levels and their relationship to early metabolic improvement after bariatric surgery

BACKGROUND

Bariatric surgery usually results in metabolic improvements within a few days from intervention, but the underlying mechanism is not completely understood and may vary depending on the bariatric procedure. Lipopolysaccharides (LPS) from gut microbiota have been proposed as a triggering factor for the inflammatory state in obesity. Roux-en-Y Gastric Bypass (RYGB) leads to a LPS decrease in the medium-term.

OBJECTIVE

To analyze LPS and LPS-binding protein (LBP) in normoglycemic (NG) and diabetic morbidly obese patients in the short-term after 2 different bariatric surgery procedures.

SETTING

University Hospital, Spain.

METHODS

Fifty morbidly obese patients underwent bariatric surgery: 24 with sleeve gastrectomy (SG) and 26 with biliopancreatic diversion (BPD). Patients were classified according to their glycemic status as NG or prediabetic/diabetic. LPS and LBP levels and biochemical and anthropometric variables were determined before and at days 15 and 90 after surgery.

RESULTS

A significant LPS reduction was seen only in the prediabetic/diabetic patients at 90 days after SG. LBP levels rose at 15 days after BPD but at 90 days returned to baseline in both NG and prediabetic/diabetic patients. At 90 days after SG, LBP levels significantly decreased compared to baseline in NG and prediabetic/diabetic patients. After multivariate analysis only the change in BMI was independently associated with the change in LBP levels at 90 days. None of the changes in biochemical or anthropometrical variables were significantly associated with the changes in LPS levels at 15 days or 90 days.

CONCLUSION

This is the first study showing that the short-term LPS decrease after bariatric surgery depends on the surgical procedure used as well as on the previous glycemic status of the patient, with SG having the greatest short-term effect on LPS and LBP levels. LBP is closely related to anthropometric variables and may be an inflammatory marker in bariatric surgery patients.

A novel long-acting glucose-dependent insulinotropic peptide analogue: enhanced efficacy in normal and diabetic rodents

AIM

Glucose-dependent insulinotropic peptide (GIP) is an incretin hormone that is released from intestinal K cells in response to nutrient ingestion. We aimed to investigate the therapeutic potential of the novel N- and C-terminally modified GIP analogue AC163794.

METHODS

AC163794 was synthesized by solid-phase peptide synthesis. Design involved the substitution of the C-terminus tail region of the dipeptidyl peptidase IV (DPP-IV)-resistant GIP analogue [d-Ala(2) ]GIP(1-42) with the unique nine amino acid tail region of exenatide. The functional activity and binding of AC163794 to the GIP receptor were evaluated in RIN-m5F β-cells. In vitro metabolic stability was tested in human plasma and kidney membrane preparations. Acute insulinotropic effects were investigated in isolated mouse islets and during an intravenous glucose tolerance test in normal and diabetic Zucker fatty diabetic (ZDF) rats. The biological actions of AC163794 were comprehensively assessed in normal, ob/ob and high-fat-fed streptozotocin (STZ)-induced diabetic mice. Acute glucoregulatory effects of AC163794 were tested in diet-induced obese mice treated subchronically with AC3174, the exendatide analogue [Leu(14) ] exenatide. Human GIP or [d-Ala(2) ]GIP(1-42) were used for comparison.

RESULTS

AC163794 exhibited nanomolar functional GIP receptor potency in vitro similar to GIP and [d-Ala(2) ]GIP(1-42). AC163794 was metabolically more stable in vitro and displayed longer duration of insulinotropic action in vivo versus GIP and [d-Ala(2) ]GIP(1-42). In diabetic mice, AC163794 improved HbA1c through enhanced insulinotropic action, partial restoration of pancreatic insulin content and improved insulin sensitivity with no adverse effects on fat storage and metabolism. AC163794 provided additional baseline glucose-lowering when injected to mice treated with AC3174.

CONCLUSIONS

These studies support the potential use of a novel GIP analogue AC163794 for the treatment of type 2 diabetes.

Incretin levels 1 month after laparoscopic single anastomosis gastric bypass surgery in non-morbid obese type 2 diabetes patients

PURPOSE

Bariatric surgery is an efficient procedure for the remission of type 2 diabetes (T2DM) from morbid obesity. However, in Asian countries, the mean body mass index (BMI) of T2DM patients is about 25 kg/m(2). Various data on patients undergoing gastric bypass surgery suggest that the control of T2DM after surgery occurs rapidly. We hypothesized that even in nonobese patients with T2DM, the levels of incretin and insulin changed along with the improvement of T2DM as a consequence of the gastric bypass.

MATERIALS AND METHODS

From March to December 2011, 12 nonobese patients (mean BMI; 26.2 kg/m(2)) with poorly-controlled [mean glycated hemoglobin (HbA1C); 9.5%] diabetes underwent gastric bypass surgery. Values related to diabetes, including incretin [gastric inhibitory peptide (GIP) and glucagon-like peptide-1 (GLP-1)] levels were measured before and 1 month after surgery. All values were measured in response to a 75 g oral glucose tolerance test (OGTT).

RESULTS

On average, the BMI decreased by 2.1 ± 0.7 kg/m(2). Mean HbA1C level decreased by 1.6 ± 2%. Oral glucose-stimulated insulin levels increased and GLP-1 levels also increased significantly. Oral glucose-stimulated GIP levels decreased sharply.

CONCLUSION

Soon after gastric bypass in nonobese T2DM patients, control of T2DM is achieved. The incretin release after oral glucose is improved. This could be a consequence of changes of the enteroinsular axis, particularly in the incretins.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Bariatric surgery for severe obesity in two adolescents with type 1 diabetes

Bariatric surgery has been effective in treating type 2 diabetes mellitus (T2DM); it has not been used frequently in obese patients with type 1 diabetes mellitus (T1DM). This is the first case series reporting on the effect of bariatric surgery on diabetes control in adolescents with T1DM. Patient A is a 19-year-old obese man with T1DM who underwent vertical sleeve gastrectomy. At 12 months after surgery he demonstrated 28% reduction in BMI. His daily total insulin requirement had decreased; however, hemoglobin A1c remained primarily unchanged at 8.8%. Patient B is a 13-year-old obese girl with an initial clinical diagnosis of T2DM controlled on only metformin. She underwent Roux-en-Y gastric bypass; at 1 month after surgery she presented in diabetic ketoacidosis and was found to have positive islet cell antibodies, which were also present before surgery. Her diagnosis was revised to T1DM, and she was started on insulin. By 28 months after surgery her BMI had decreased by 42%. Since initiation of insulin, her daily total insulin requirement had decreased, but hemoglobin A1c had significantly worsened from 6.3% to 10%. We found that despite significant weight loss, improvements in cardiovascular risk factors (dyslipidemia and obstructive sleep apnea), and quality of life in our patients, bariatric surgery does not necessarily lead to improved glycemic control of T1DM. Patients with T1DM have ongoing dependency on exogenous insulin, and optimal glycemic control still depends on patient compliance with diabetes care.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Clinical considerations for the management of residual diabetes following bariatric surgery

Residual diabetes following bariatric surgery is increasingly recognized despite initial weight loss. It occurs more commonly following banding and sleeve gastrectomy procedures than with gastric bypass, is associated with long duration and advanced stages of diabetes and is exacerbated by weight regain. Long-term diabetes management following various gastric restrictive surgery (i.e. lap banding) requires targeting weight loss, insulin resistance and insulin secretion defects with antidiabetic agents that have weight negative or neutral effects. In contrast, re-emergence of hyperglycaemia following gastric bypass may require targeting β-cell failure with insulin analogues. Revisional bariatric surgery is also a consideration. On the basis of our experience, we propose a clinical approach for long-term management of diabetes following various bariatric procedures in the presence and absence of weight regain that is based on recognized pathophysiological effects of these procedures on diabetes remission.

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.

A comparative study of gastric banding and sleeve gastrectomy in an obese diabetic rat model

BACKGROUND

Laparoscopic sleeve gastrectomy (SG) is now a typical restrictive bariatric procedure. The aim of this study was to evaluate the efficacy of SG in comparison with gastric banding (GB) in an obese diabetic rat model.

METHODS

Forty-five male Zucker diabetic fatty rats were divided into three groups: sham-operated (SO) control, GB, and SG. The rats were followed for 6 weeks after surgery, and their body weight change, cumulative food intake, metabolic parameters, plasma levels of ghrelin, glucagon-like peptide-1 and adiponectin, oral glucose tolerance test (OGTT), insulin tolerance test (ITT), and gastric emptying rate were measured.

RESULTS

The GB and SG groups showed significant decreases in weight, cumulative intake, and metabolic parameters and significant improvement of OGTT and ITT results compared with the SO group. There were no significant differences in weight and cumulative food intake between the groups. However, the SG group showed significantly higher gastric emptying rate and plasma level of adiponectin and lower plasma levels of free fatty acid, total cholesterol, and ghrelin compared with the GB group. Furthermore, the SG group showed improvement of OGTT and ITT results in comparison with the GB group.

CONCLUSIONS

In obese diabetic rats, SG may improve glucose and lipid metabolism compared with GB, although there was no significant difference in the effect on body weight loss between the two procedures. The hormonal and digestive changes induced by SG may have relevance to the effects on metabolism.

Improvement of psoriasis during exenatide treatment in a patient with diabetes

CONTEXT AND AIM

Psoriasis is an immune-mediated skin disorder frequently associated with obesity and type 2 diabetes (T2D). This report is of a clinically significant improvement in psoriasis lesions in a patient with T2D during treatment with a GLP-1 receptor agonist (exenatide).

OBSERVATION

A 61-year-old male patient (BMI: 25.5 kg/m(2)) with T2D treated with metformin and sulphonylureas had also complained, since 1980, of extensive psoriasis that required multiple steroid-based treatments [Psoriasis Area and Sensitivity Index (PASI) score: 11]. In September 2008, his diabetes treatment was intensified with exenatide (Byetta(®)) to improve poor glycaemic control. The patient, as expected, lost weight and reduced HbA(1c) levels from 65 mmol/mol to 56 mmol/mol. However, after just 1 month of treatment with exenatide, the patient also reported a dramatic improvement in psoriatic plaques that was confirmed at the 1-year follow-up (PASI: estimated at 3-4). Withdrawal of exenatide was associated with weight gain, deterioration of glycaemic control and deterioration of psoriasis (PASI:>10). After reinstating exenatide treatment, the patient again reported a prompt improvement in psoriasis (PASI: 3.1).

CONCLUSION

There was a major and rapid improvement in psoriasis in our patient with T2D following treatment with exenatide. A possible mechanism might be through direct modulation of the immune system by GLP-1 receptor agonists.

Outcome after gastrectomy in gastric cancer patients with type 2 diabetes

AIM: To evaluate the prognosis of type II diabetes mellitus (T2DM) after gastrectomy and related factors in gastric cancer patients.

METHODS: 403 gastric cancer patients with T2DM were studied, who underwent gastrectomy between May 2003 and September 2009. A review of medical records and telephone interviews was performed in this cross-sectional study. The factors included in the statistical analysis were as follows: gender, age, type of surgery, preoperative body mass index (BMI), current BMI, BMI reduction ratio, preoperative insulin or oral diabetic medicine requirement, follow-up duration, and current state of diabetes. Assessment of diabetes status after surgery was classified into four categories according to the change in hypoglycemic agents after surgery and present status of T2DM: resolution, improvement, same, and worse.

RESULTS: The mean follow-up duration was 33.7 mo (± 20.6 mo), preoperative BMI was 24.7 kg/m² (± 3.0 kg/m²), and BMI reduction ratio was 9.8% (± 8.6%). After surgery, T2DM was cured in 58 patients (15.1%) and was improved in 117 patients (30.4%). According to the type of surgery, the BMI reduction ratio was significantly higher in the total gastrectomy and Roux-en-Y reconstruction group [14.2% ± 9.2% vs 9.2% ± 7.7% (Billroth II group), P < 0.001] and significantly lower in the subtotal gastrectomy and Billroth I reconstruction group [7.6% ± 8.0%, 9.2% ± 7.7% (Billroth II group), P < 0.001]. The BMI reduction ratio, follow-up duration after surgery, type of surgery, extent of gastrectomy, and performance of duodenal bypass were significantly correlated to the course of T2DM (P < 0.05). The BMI reduction ratio was the most influential factor on T2DM status. In a subgroup analysis of patients with a BMI reduction ratio of 10% or less (n = 206), T2DM was cured in 15 (7.6%) patients and was improved in 57 (28.8%) patients after surgery, and only the duration of surgery was significantly correlated to T2DM status (P = 0.022).

CONCLUSION: The course of T2DM was significantly correlated to the BMI reduction ratio but not to the type of surgery without a significant change in BMI.

Glucagon-like peptide-1 (GLP-1) and the regulation of human invariant natural killer T cells: lessons from obesity, diabetes and psoriasis

AIMS/HYPOTHESIS

The innate immune cells, invariant natural killer T cells (iNKT cells), are implicated in the pathogenesis of psoriasis, an inflammatory condition associated with obesity and other metabolic diseases, such as diabetes and dyslipidaemia. We observed an improvement in psoriasis severity in a patient within days of starting treatment with an incretin-mimetic, glucagon-like peptide-1 (GLP-1) receptor agonist. This was independent of change in glycaemic control. We proposed that this unexpected clinical outcome resulted from a direct effect of GLP-1 on iNKT cells.

METHODS

We measured circulating and psoriatic plaque iNKT cell numbers in two patients with type 2 diabetes and psoriasis before and after commencing GLP-1 analogue therapy. In addition, we investigated the in vitro effects of GLP-1 on iNKT cells and looked for a functional GLP-1 receptor on these cells.

RESULTS

The Psoriasis Area and Severity Index improved in both patients following 6 weeks of GLP-1 analogue therapy. This was associated with an alteration in iNKT cell number, with an increased number in the circulation and a decreased number in psoriatic plaques. The GLP-1 receptor was expressed on iNKT cells, and GLP-1 induced a dose-dependent inhibition of iNKT cell cytokine secretion, but not cytolytic degranulation in vitro.

CONCLUSIONS/INTERPRETATION

The clinical effect observed and the direct interaction between GLP-1 and the immune system raise the possibility of therapeutic applications for GLP-1 in inflammatory conditions such as psoriasis.

Type 2 diabetes in obese patients with body mass index of 30-35 kg/m2: sleeve gastrectomy versus medical treatment

BACKGROUND

Type 2 diabetes mellitus (T2DM) and obesity are diseases of epidemic proportions. Long-term realistic weight loss by nonsurgical methods has a variable effect on glycemic control, and only a proportion of patients with T2DM have a worthwhile response. Laparoscopic sleeve gastrectomy (LSG) has been proposed as an advantageous bariatric procedure for patients with a lower body mass index (BMI). Our objective was to compare the effects of LSG and medical therapy on patients with T2DM and a BMI of <35 kg/m(2).

METHODS

A total of 18 nonmorbidly obese patients with T2DM, diagnosed according to the American Diabetes Association guidelines, were consecutively enrolled. Of these patients, 9 underwent LSG (group A) and 9 underwent conventional medical therapy (group B). The 2 groups were matched for BMI, glycated hemoglobin (HbA1c) and C-peptide levels, pretrial therapy type, and number of patients with a T2DM duration of >10 years.

RESULTS

In group A, T2DM resolution was achieved in 8 (88.8%) of the 9 patients (T2DM duration 5.2 yr). Hypertension was controlled in all 8 of 9 patients. Dyslipidemia was corrected. In 1 patient, obstructive sleep apnea syndrome improved. In group B, all 9 patients continued to have T2DM and required hypertensive and hypolipemic therapies throughout the observation period. At baseline, 3 patients were affected by obstructive sleep apnea syndrome and remained affected 1 year later.

CONCLUSION

The results of the present study have confirmed the efficacy of LSG in the treatment of nonmorbidly obese T2DM patients, with a remission rate of 88.8% without undesirable excessive weight loss. The results in this group of patients add to those obtained by us in patients with a BMI >35 kg/m(2).

Effects of bilio-pancreatic diversion on diabetic complications: a 10-year follow-up

OBJECTIVE

The surgical option could represent a valid alternative to medical therapy in some diabetic patients. However, no data are available on long-term effects of metabolic surgery on diabetic complications. We aimed to determine whether patients with newly diagnosed type 2 diabetes who underwent bilio-pancreatic diversion (BPD) had less micro- and macrovascular complications than those who received conventional therapy.

RESEARCH DESIGN AND METHODS

This was an unblinded, case-controlled trial with 10-years' follow-up, conducted from July 1998 through October 2009 at the Day Hospital of Metabolic Diseases, Catholic University, Rome, Italy. A consecutive sample of 110 obese patients (BMI >35 kg/m(2)) with newly diagnosed type 2 diabetes was enrolled. The study was completed by 50 subjects. The main outcome measure was long-term effects (10 years) of BPD versus those associated with conventional therapy on microvascular outcome, micro- and macroalbuminuria, and glomerular filtration rate (GFR). Secondary measures included macrovascular outcomes, type 2 diabetes remission, glycated hemoglobin, and hyperlipidemia.

RESULTS

Ten-year GFR variation was -45.7 ± 18.8% in the medical arm and 13.6 ± 24.5% in the surgical arm (P < 0.001). Ten-year hypercreatininemia prevalence was 39.3% in control subjects and 9% in BPD subjects (P = 0.001). After 10 years, all BPD subjects recovered from microalbuminuria, whereas microalbuminuria appeared or progressed to macroalbuminuria in control subjects. Three myocardial infarctions, determined by electrocardiogram, and one stroke occurred in control subjects. After the 10-year follow-up, coronary heart disease (CHD) probability was 0.22 ± 0.10 and 0.05 ± 0.04 in the medical and surgical groups, respectively (P < 0.001). Remission from type 2 diabetes was observed in all patients within 1 year of surgery. Surgical and medical subjects had lost 34.60 ± 10.25 and 0.38 ± 6.10% of initial weight at the 10-year follow-up (P < 0.001).

CONCLUSIONS

Renal and cardiovascular complications were dramatically reduced in the surgical arm, indicating long-term benefits of BPD on diabetic complications, at least in the case of morbid obesity with decompensated type 2 diabetes.

Metabolic surgery for the treatment of type 2 diabetes in patients with BMI <35 kg/m2: an integrative review of early studies

Type 2 diabetes mellitus (T2DM) resolution in morbidly obese patients following metabolic surgery suggests the efficacy of T2DM surgery in non-morbidly obese patients (body mass index [BMI] <35 kg/m(2)). This literature review examined research articles in English over the last 30 years (1979-2009) that addressed surgical resolution of T2DM in patients with a mean BMI <35. Weighted and simple means (95% CI) were calculated to analyze study outcomes. Sixteen studies met inclusion criteria; 343 patients underwent one of eight procedures with 6-216 months follow-up. Patients lost a clinically meaningful, not excessive, amount of weight (from BMI 29.4 to 24.2; -5.1), moving from the overweight into the normal weight category. There were 85.3% patients who were off T2DM medications with fasting plasma glucose approaching normal (105.2 mg/dL, -93.3), and normal glycated hemoglobin, 6% (-2.7). In subgroup comparison, BMI reduction and T2DM resolution were greatest following malabsorptive/restrictive procedures, and in the preoperatively mildly obese (30.0-35.0) vs overweight (25.0-25.9) BMI ranges. Complications were few with low operative mortality (0.29%). Novel and/or known mechanisms of T2DM resolution may be engaged by surgery at a BMI threshold <or=30. The majority of low-BMI patients experienced resolution of laboratory and clinical manifestations of T2DM without inappropriate weight loss.

Amelioration of insulin requirement in patients undergoing duodenal bypass for reasons other than obesity implicates foregut factors in the pathophysiology of type II diabetes

BACKGROUND

Foregut diversion and weight loss have been proposed as potential mechanisms for resolution of type II diabetes mellitus (T2DM) observed in patients undergoing gastric bypass for obesity. To support or refute the role of the foregut, we analyzed glycemic control in T2DM patients before and after foregut bypass for reasons other than morbid obesity.

STUDY DESIGN

Using ICD9/CPT codes, we identified patients undergoing Roux-en-Y gastrojejunostomy (RY) or Billroth II (BII) reconstruction over 10 years. Fasting blood glucose, insulin or oral diabetic agent requirement, and body mass index (BMI) before and after surgery were tabulated and compared using the Student's t-test. Linear regression was applied to determine specific factors predictive of resolution or improvement in glycemic control including age, duration of diabetes, antidiabetic regimen, type of operation, and surgical indication.

RESULTS

Between 1996 and 2006, we identified 24 patients with T2DM out of a cohort of 209 who underwent either RY (12 of 24) or BII reconstruction (12 of 24) for cancer or peptic ulcer disease and survived more than 30 days after operation. Of this group, 75% were overweight (18 of 24 with BMI < 30 kg/m(2)) and 25% were class I morbidly obese (6 of 24 with BMI 30 to 35 kg/m(2)). Seventeen patients (71%) had either complete resolution (7 of 24 or 29%) or significant reduction (10 of 24 or 42%) in medication requirements; 7 patients (29%) did not have any improvement. Logistic regression failed to identify specific factors predicting improved glycemic control.

CONCLUSIONS

Complete resolution of T2DM in patients undergoing duodenal diverting surgery occurs in about one-third of nonobese patients. Improved glycemic control occurs in more than two-thirds and cannot be explained by surgically related weight loss alone. Surgical cure of T2DM may be possible in carefully selected nonobese patients.

Postoperative metabolic and nutritional complications of bariatric surgery

Bariatric surgery has become an increasingly important method for management of medically complicated obesity. In patients who have undergone bariatric surgery, up to 87% with type 2 diabetes mellitus develop improvement or resolution of their disease postoperatively. Bariatric surgery can reduce the number of absorbed calories through performance of either a restrictive or a malabsorptive procedure. Patients who have undergone bariatric surgery require indefinite, regular follow-up care by physicians who need to follow laboratory parameters of macronutrient as well as micronutrient malnutrition. Physicians who care for patients after bariatric surgery need to be familiar with common postoperative syndromes that result from specific nutrient deficiencies.

Remission of type 2 diabetes in obese patients after bariatric surgery: the role of incretins

The prevalence of obesity and type 2 diabetes has increased over recent decades. Bariatric surgery has been widely used in clinical practice. There are three categories of bariatric surgery: restrictive surgery, malabsorptive surgery, and combined restrictive and malabsorptive surgery. Bariatric surgery causes not only weight loss but also a remarkable and durable remission of type 2 diabetes mellitus. However, the mechanism of diabetes resolution remains unclear. In addition to weight loss and food intake restriction, incretins also seem to contribute to the resolution of type 2 diabetes following bariatric surgery. In this article, we will review the efficacy and safety of various bariatric procedures and the mechanism of diabetes resolution resulting from bariatric surgery.

Glucagon-like peptide 1 and glucose-dependent insulinotropic polypeptide: new advances

PURPOSE OF REVIEW

This article highlights recent advances in our understanding of glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) physiology and their various sites of action beyond the incretin effect.

RECENT FINDINGS

Both GLP-1 and GIP stimulate insulin secretion in a glucose-dependent manner and are thus classified as incretins. Beyond glucose-dependent insulin secretion, the peptides have common actions on islet beta cells, leading beta-cell proliferation and resistance to apoptosis. However, the action of GLP-1 and GIP is not limited to the islet cells; they have regulatory functions in many organs. Recent evidence has suggested that GLP-1 has important beneficial effects in the cardiovascular system and central nervous system. GIP may play a role in promoting energy storage in humans, enhances bone formation via stimulation of osteoblast proliferation and inhibition of apoptosis and may play a role in central nervous system function.

SUMMARY

These new findings suggest further application of these hormones for the treatment of conditions such as cardiovascular disease and obesity.

"Metabolic" surgery for treatment of type 2 diabetes mellitus

OBJECTIVE

To discuss the potential contribution of "metabolic" surgery in providing optimal management of patients with type 2 diabetes mellitus (T2DM).

METHODS

A literature search was performed with use of PubMed, and the clinical experience of the authors was also considered.

RESULTS

Bariatric-or, more appropriately, metabolic-surgical procedures have been shown to provide dramatic improvement in blood glucose levels, blood pressure, and lipid control in obese patients with T2DM. In these patients, metabolic surgery involves a low risk of short-term mortality and a significant long-term survival advantage, whereas the diagnosis of diabetes is associated with significant long-term mortality. Experimental studies in animals and clinical trials suggest that gastrointestinal bypass procedures can control diabetes and associated metabolic alterations by mechanisms independent of weight loss. As a result, the use of bariatric surgery and experimental gastrointestinal manipulations to treat T2DM is increasing, even among less obese patients. Although body mass index (BMI) currently is the most important factor for identifying candidates for bariatric surgery, evidence shows that a specific cutoff BMI value cannot accurately predict successful surgical outcomes. Furthermore, BMI appears limited in defining the risk profile for patients with T2DM.

CONCLUSION

Current BMI-based criteria for performance of bariatric surgery are not adequate for determining eligibility for operative treatment in patients with diabetes. Large clinical trials, comparing bariatric surgery versus optimal medical care of patients with T2DM, should be given priority in order to define the role of surgery in the management of diabetes. Recognizing the need to work as a multidisciplinary team that includes endocrinologists and surgeons is an initial step in addressing the issues and opportunities that surgery offers to diabetes care and research.

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.

Long-term effects of laparoscopic sleeve gastrectomy, gastric bypass, and adjustable gastric banding on type 2 diabetes

BACKGROUND

This study aimed to compare the efficacy of laparoscopic sleeve gastrectomy (SG) with that of laparoscopic gastric bypass (GBP) and laparoscopic adjustable gastric banding (AGB) for glucose homeostasis in morbidly obese subjects with type 2 diabetes mellitus (T2DM) at a 3-year follow-up assessment and to elucidate the role of weight loss in the T2DM resolution after SG.

METHODS

For this study, 60 morbidly obese T2DM patients (44 females and 16 males) who underwent AGB (24 patients), GBP (16 patients), or SG (20 patients) between 1996 and 2008 were retrospectively analyzed. Age, sex, body mass index (BMI), estimated weight loss (EWL), fasting glycemia, HbA1c, euglycemic hyperinsulinemic clamp, discontinuation of diabetes treatment, and time until interruption of therapy were evaluated.

RESULTS

In the study, 54 patients received oral hypoglycemic agents for at least 12 months before surgery, and 6 patients received insulin. The mean follow-up period was 36 months. The resolution rate was 60.8% for the AGB patients, 81.2% for the GBP patients, and 80.9% for the SG patients. The postoperative time until interruption of therapy was 12.6 months for the AGB patients, 3.2 months for the GBP patients, and 3.3 months for the SG patients. The hyperinsulinemic euglycemic clamp test was performed 12 months after surgery for the cured patients. Insulin resistance was restored to normal values in all the patients. The greatest improvement from preoperative values occurred in the SG group. For the not-cured GBP and SG patients, an improvement of 120 mg/dl in fasting plasma glucose was observed 3 months after the surgery, suggesting an enhancement in insulin sensitivity, which determines better medical control. The resolution rate remained constant at the 36-month follow-up evaluation in both the GBP and SG groups.

CONCLUSIONS

All three bariatric procedures are effective in treating diabetes, with a 3-year follow-up evaluation showing an effect that lasts. The AGB procedure was the least effective. The antidiabetic effect was similarly precocious after GBP and SG compared with AGB. This difference may indicate that a hormonal mechanism may be involved, independent of weight loss.