Early effects of gastric banding (LGB) and of biliopancreatic diversion (BPD) on insulin sensitivity and on glucose and insulin response after OGTT

Improved Insulin Secretion Response and Beta-cell Function Correlated with Increased Prolactin Levels After Laparoscopic Sleeve Gastrectomy in Morbidly Obese Patients with Acanthosis Nigricans

OBJECTIVE

To explore insulin secretion patterns, β-cell function, and serum prolactin (PRL) concentrations in Chinese morbidly obese patients with Acanthosis nigricans (AN) and their alterations after laparoscopic sleeve gastrectomy (LSG).

METHODS

A total of 138 morbidly obese subjects undergoing LSG were categorized as simple obesity without AN (OB group, n = 55) and obesity with AN (AN group, n = 83). Oral glucose tolerance test (OGTT), PRL, and related metabolic indices were performed pre- and 12 months post-LSG. Insulin secretion patterns were derived from insulin secretion peak time during OGTT: type I (peak at 30 or 60 min) and type II (peak at 120 or 180 min).

RESULTS

Preoperatively, AN group showed significantly higher proportions of type II insulin secretion pattern, fasting insulin (FINS), and homeostatic model assessment of insulin resistance (HOMA-IR) whereas lower oral glucose insulin sensitivity (OGIS), insulinogenic index (IGI), and disposition index (DI) than OB group, which were improved significantly at 12 months postoperatively in both groups, more pronounced in AN group. Intriguingly, serum PRL declined substantially in AN group than OB group at baseline whereas elevated only in the AN group post-LSG. After adjusting for confounding factors, elevated PRL correlated significantly with increased IGI and DI, and decreased HOMA-IR in both genders, as well as increased OGIS in females, which was detected only in the AN group CONCLUSION: Morbidly obese patients with AN presented delayed insulin secretion response, impaired insulin secretion, and β-cell dysfunction, which were significantly improved by LSG and might benefit from elevated PRL.

Glucose metabolism after bariatric surgery: implications for T2DM remission and hypoglycaemia

Although promising therapeutics are in the pipeline, bariatric surgery (also known as metabolic surgery) remains our most effective strategy for the treatment of obesity and type 2 diabetes mellitus (T2DM). Of the many available options, Roux-en-Y gastric bypass (RYGB) and vertical sleeve gastrectomy (VSG) are currently the most widely used procedures. RYGB and VSG have very different anatomical restructuring but both surgeries are effective, to varying degrees, at inducing weight loss and T2DM remission. Both weight loss-dependent and weight loss-independent alterations in multiple tissues (such as the intestine, liver, pancreas, adipose tissue and skeletal muscle) yield net improvements in insulin resistance, insulin secretion and insulin-independent glucose metabolism. In a subset of patients, post-bariatric hypoglycaemia can develop months to years after surgery, potentially reflecting the extreme effects of potent glucose reduction after surgery. This Review addresses the effects of bariatric surgery on glucose regulation and the potential mechanisms responsible for both the resolution of T2DM and the induction of hypoglycaemia.

Can Metabolite and Hormone Profiles Provide a Rationale for Choosing Between Bariatric Procedures?

PURPOSE

There are no formal guidelines for choosing among different bariatric surgery procedures for obesity treatment. So, our aim was to evaluate whether post-absorptive metabolite and hormone profiles could aid the surgeon decision when considering bariatric surgery interventions.

MATERIALS AND METHODS

Subjects (N=38) previously submitted to biliopancreatic diversion with duodenal switch (BPD-DS, n=9), single anastomosis duodenal-ileum bypass with sleeve gastrectomy (SADI-S, n= 9), long biliopancreatic limb Roux-en-Y gastric bypass (RYGB-M, n= 11), and classic RYGB (RYGB-C, n= 9) underwent a mixed meal test to evaluate post-absorptive glucose, total amino acid (AA), insulin, and GLP-1 profiles.

RESULTS

Glucose, AA, insulin, and GLP-1 excursions were lower after BPD-DS when compared to other surgeries. SADI-S resulted in lower glucose but similar AA and insulin excursions when compared to RYGB-M. The highest GLP-1 excursion was observed after RYGB-M. There were no significant differences in glucose or AA post-prandial excursions between RYGB procedures, yet insulin excursion was higher after RYGB-C when compared to RYGB-M.

CONCLUSION

Post-prandial metabolite excursions diverge across bariatric procedures being lowest after BPD-DS, intermediate after SADI-S, and highest after RYGB, in parallel with the anti-diabetic efficacy and malabsorption risk reported for each type of intervention. SADI-S and RYGB-M seem to elicit similar post-prandial hormonal profiles, with potentially lower risk of protein malnutrition when compared to BPD-DS. Post-absorptive metabolite and hormone profiles could provide a rationale as decision-aid when choosing among bariatric surgery interventions, as long as these findings are validated in future trials.

A 9 years comparison of weight loss, disappearance of obesity, and resolution of diabetes mellitus with biliointestinal bypass and with adjustable gastric banding: experience of a collaborative network

AIMS

Long-term comparisons between bariatric surgical techniques have been performed for gastric bypass (RYGB), sleeve gastrectomy (LSG), and biliopancreatic diversion (BPD) vs gastric banding (LAGB), but short-term studies (6 months-4 years) have only compared biliointestinal bypass (BIBP) and LAGB. The participating institutions regularly perform both BIBP and LAGB with a common protocol, and the aim of this retrospective study was to compare long-term effects of the two procedures on body weight, on clinical and metabolic variables, and on resolution of obesity and of diabetes.

METHODS

All procedures performed between 01/01/1998 and 31/12/2005 were considered; 73 out of 91 patients undergoing BIBP, and 154 out of 249 patients undergoing LAGB were evaluable up to 9 years.

RESULTS

BIBP was significantly more effective than LAGB in terms of weight loss and of resolution of obesity (BMI < 30 kg/m²), in terms of decrease of systolic blood pressure and of serum cholesterol, and similar in terms of resolution of diabetes. In addition, the effect of BIBP was stable, while the effect of LAGB decreased with time.

CONCLUSIONS

Both BIBP and LAGB exert long-term effects on body weight, on blood pressure, and on resolution of diabetes mellitus; the effect of BIBP is significantly greater than the effect of LAGB in terms of weight loss, resolution of obesity, of control of systolic blood pressure and of serum cholesterol, but not in terms of resolution of diabetes.

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.

Role of bariatric-metabolic surgery in the treatment of obese type 2 diabetes with body mass index <35 kg/m2: a literature review

Bariatric surgery has been used to treat type 2 diabetes mellitus (T2DM); however, its efficacy is still debatable. This literature review analyzed articles that evaluated the effects of bariatric surgery in treatment of T2DM in obese patients with a body mass index (BMI) of <35 kg/m(2). A paired t test was applied for the analysis of pre- and postintervention mean BMI, fasting plasma glucose (FPG), and glycosylated hemoglobin (A1c) values. A significant (P<0.001) reduction in BMI (from 29.95±0.51 kg/m(2) to 24.83±0.44 kg/m(2)), FPG (from 207.86±8.51 mg/dL to 113.54±4.93 mg/dL), and A1c (from 8.89±0.15% to 6.35±0.18%) was observed in 29 articles (n=675). T2DM resolution (A1c <7% without antidiabetes medication) was achieved in 84.0% (n=567) of the subjects. T2DM remission, control, and improvement were observed in 55.41%, 28.59%, and 14.37%, respectively. Only 1.63% (n=11) of the subjects presented similar or worse glycemic control after the surgery. T2DM remission (A1c <6% without antidiabetes medication) was higher after mini-gastric bypass (72.22%) and laparoscopic/Roux-en-Y gastric bypass (70.43%). According to the Foregut and Hindgut Hypotheses, T2DM results from the imbalance between the incretins and diabetogenic signals. The procedures that remove the proximal intestine and do ileal transposition contribute to the increase of glucagon-like peptide-1 levels and improvement of insulin sensitivity. These findings provide preliminary evidence of the benefits of bariatric-metabolic surgery on glycemic control of T2DM obese subjects with a BMI of <35 kg/m(2). However, more clinical trials are needed to investigate the metabolic effects of bariatric surgery in T2DM remission on pre-obese and obese class I patients.

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.

Impact of bariatric surgery on comorbidities

Published data show that bariatric surgery not only leads to significant and sustained weight loss but also resolves or improves multiple comorbidities associated with morbid obesity. Evidence suggests that the earlier the intervention the better the resolution of comorbidities. Patients with metabolic syndrome and comorbidities associated with morbid obesity should be promptly referred for consideration for bariatric surgery earlier in the disease process.

Gastric emptying of orally administered glucose solutions and incretin hormone responses are unaffected by laparoscopic adjustable gastric banding

BACKGROUND

Laparoscopic adjustable gastric banding (LAGB) provides weight loss in obese individuals and is associated with improved glucose homeostasis and resolution of type 2 diabetes. However, in most available reports, potentially inappropriate methodology has been applied when measuring the impact of LAGB on glucose intolerance. In order to clarify the applicability of the diagnostic 75 g-oral glucose tolerance test (OGTT) to measure the effect of LAGB on glucose metabolism, we investigated the effect of LAGB on gastric emptying for liquids as well as pancreatic and incretin hormone responses.

METHODS

Eight obese patients (three with normal glucose tolerance, three with impaired glucose tolerance, and two with type 2 diabetes; age 47.5 ± 1.1 years (mean±SEM); body mass index 44 ± 1 kg/m²; HbA(1)c 6.2 ± 0.4%) underwent a 75 g-oral glucose tolerance test with 1 g acetaminophen before and ~6 weeks after LAGB.

RESULTS

A small weight reduction was seen after LAGB (125 ± 8 vs. 121 ± 8 kg, P = 0.014). No differences in determinants of gastric emptying were observed before and after LAGB (area under the serum acetaminophen curve 10.1 ± 0.6 vs. 9.8 ± 0.5 mM x 4 h, P = 0.8; peak acetaminophen concentration 62 ± 3 vs. 61 ± 3 μM, P = 0.8; acetaminophen peak time 98 ± 6 vs. 100 ± 6 min, P = 0.9). No differences in plasma glucose, insulin, C-peptide, glucagon, glucose-dependent insulinotropic polypeptide, or glucagon-like peptide-1 responses to the OGTT were observed before as compared to after LAGB.

CONCLUSIONS

OGTT can be used to evaluate glucose tolerance in obese patients before and after LAGB without bias from changes in gastric emptying. LAGB has no direct impact on incretin hormone secretion.