Early insulin sensitivity after restrictive bariatric surgery, inconsistency between HOMA-IR and steady-state plasma glucose levels

SPINA Carb: a simple mathematical model supporting fast in-vivo estimation of insulin sensitivity and beta cell function

Modelling insulin-glucose homeostasis may provide novel functional insights. In particular, simple models are clinically useful if they yield diagnostic methods. Examples include the homeostasis model assessment (HOMA) and the quantitative insulin sensitivity check index (QUICKI). However, limitations of these approaches have been criticised. Moreover, recent advances in physiological and biochemical research prompt further refinement in this area. We have developed a nonlinear model based on fundamental physiological motifs, including saturation kinetics, non-competitive inhibition, and pharmacokinetics. This model explains the evolution of insulin and glucose concentrations from perturbation to steady-state. Additionally, it lays the foundation of a structure parameter inference approach (SPINA), providing novel biomarkers of carbohydrate homeostasis, namely the secretory capacity of beta-cells (SPINA-GBeta) and insulin receptor gain (SPINA-GR). These markers correlate with central parameters of glucose metabolism, including average glucose infusion rate in hyperinsulinemic glucose clamp studies, response to oral glucose tolerance testing and HbA1c. Moreover, they mirror multiple measures of body composition. Compared to normal controls, SPINA-GR is significantly reduced in subjects with diabetes and prediabetes. The new model explains important physiological phenomena of insulin-glucose homeostasis. Clinical validation suggests that it may provide an efficient biomarker panel for screening purposes and clinical research.

Higher HOMA-IR index is associated with increased excess weight loss in patients with BMI≥35kg/m2 after vertical gastrectomy

INTRODUCTION

Bariatric surgery is considered the most effective treatment for severe obesity. However, it is not clear if patients with diabetes mellitus or insulin resistance have the same response than patients without those conditions. Our objective was to evaluate association between pre-surgical HOMA-IR index and percentage of excess weight loss (EWL%) one year after bariatric surgery using sleeve gastrectomy.

METHODS

Retrospective cohort including patients ≥18 years old with BMI≥35kg/m², who underwent primary sleeve gastrectomy between 2014-2017 at the Avendaño Medical Center, Peru. Only patients with Type 2 Diabetes, Hypertension, or Dyslipidemia were included. EWL% ≥60% one year after surgery was considered satisfactory. Crude and adjusted Lineal and Poisson regression with robustness was used to assess statistical associations with EWL%.

RESULTS

Ninety-one patients were included with a median of 34 years, and 57.1% were women. 85.7% had insulin resistance as per HOMA-IR. One year after surgery, 76.9% had a satisfactory EWL%. The lineal model showed .29% less EWL% per each extra year of life (P=.019), and .93% more EWL% per each extra HOMA-IR point (P=.004). The adjusted Poisson model showed 2% lower risk of having a satisfactory EWL% per each additional year of life (P=.050), and 2% more chance of success per each additional HOMA-IR point (P=.038).

CONCLUSIONS

There was association between a higher pre-surgical HOMA-IR index and increased EWL% one year after surgery. It is possible that insulin resistance does not affect negatively sleeve gastrectomy outcomes.

Hormonal responses and test meal intake among obese teenagers before and after laparoscopic adjustable gastric banding

BACKGROUND

Relatively little is known about changes in eating behavior or hormonal responses to food after bariatric surgery in adolescents.

OBJECTIVE

This study compared eating behavior and hormones among adolescents in a bariatric surgery program with those in nonoverweight control adolescents and evaluated changes before and after laparoscopic adjustable gastric banding (LAGB).

DESIGN

Fasting leptin, peptide YY (PYY), and ghrelin concentrations were obtained, and postprandial ghrelin and PYY area under the curve (AUC) were assessed after a single-item breakfast. Intake from an ad libitum lunchtime multi-item meal was measured.

RESULTS

Compared with controls (n = 9), all presurgical candidates (n = 20) had significantly greater fasting leptin, lower fasting ghrelin, and lower AUC ghrelin but similar PYY and AUC PYY. Preoperative candidates did not differ from controls in total energy consumed during the test meal. Postoperatively, among the 11 participants with data both before and after surgery, BMI (in kg/m(2)) decreased by 3.5 (P < 0.001), significantly less energy was consumed in the test meal, and a smaller number of foods were selected. AUC ghrelin and PYY did not significantly change before or after LAGB.

CONCLUSIONS

Few significant short-term changes were observed in appetitive hormones after LAGB. It is unclear whether objective measures of eating behavior will prove useful in evaluating the impact of bariatric surgery on outcomes. This trial was registered at clinicaltrials.gov as CT00764127.

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.

Biliopancreatic diversion with duodenal switch in patients with type 2 diabetes mellitus: is the chance of complete remission dependent on therapy and duration of insulin treatment?

BACKGROUND

Rapid resolution of type 2 diabetes mellitus (T2DM) is a common feature after intestinal bypass surgery bypassing the duodenum and parts of the jejunum. However, the parameters determining the individual chance of remission are imprecisely defined.

METHODS

Biliopancreatic diversion with duodenal switch and sleeve gastrectomy (BPD-DS) was performed in n = 86 patients with T2DM (mean age 50 years, range 26-68, 51 females; BMI 47 kg/m(2), range 26-71). The patients were retrospectively divided into 4 groups according to the treatment modality and the duration of insulin treatment preoperatively: n = 18 patients were treated with oral antidiabetic drugs only (group 1); n = 32, n = 24, and n = 12 patients were treated with insulin for less than 5 years, for 5-10 years, and for more than 10 years (groups 2, 3, and 4), respectively.

RESULTS

At discharge from hospital, all patients of groups 1 and 2 were free of insulin usage, 30% and 75% of the patients of groups 3 and 4 used up to 48 units of insulin per day (mean 24, n = 16). After 1 year, only 4 patients of group 4 permanently required small amounts of insulin (mean 17 units per day) to keep blood glucose below 200 mg/dl. These 4 patients had been using insulin preoperatively for 13, 15, 22, and 25 years. In 3 of these 4 patients, fasting C-peptide was measured and found to be low (<1.2 ng/ml). The rate of complete remission of diabetes for the whole study population was 91%.

CONCLUSION

BPD-DS reliably causes rapid and complete remission of T2DM in all patients on oral antidiabetic drugs and in patients with insulin treatment for less than 5 years. In patients with insulin treatment longer than 5 or 10 years, complete remission rates decline to 88 and 66%, respectively. A low C-peptide preoperatively might be a specific adverse prognostic parameter for the chance of diabetes remission.

Metabolic intestinal bypass surgery for type 2 diabetes in patients with a BMI <35 kg/m2: comparative analysis of 16 patients undergoing either BPD, BPD-DS, or RYGB

BACKGROUND

Metabolic surgery for type 2 diabetes mellitus in patients with low body mass index (BMI) is a novel concept. Early studies show the surgery to be safe and effective but are inconclusive regarding the most effective procedure.

METHODS

Metabolic intestinal bypass surgery was performed in n = 16 patients with type 2 diabetes and a BMI < 35 kg/m(2) (mean age 56 years, range 36-68; 8 females; mean BMI 32 kg /m(2), range 26-34.5). Biliopancreatic diversion with duodenal switch (BPD-DS), biliopancreatic diversion according to Scopinaro (BPD), and Roux-en-Y gastric bypass (RYGB) were performed in 7, 5, and 4 diabetic patients, respectively. Mean preoperative duration of medical antidiabetic therapy was 16 years (range 4-40). Thirteen patients used insulin on average for 6 years (range 1-12), the mean insulin requirement was 92 IU per day (range 30-140). The analysis was accomplished retrospectively from data prospectively collected in our data base.

RESULTS

At discharge from hospital, only 3 of the 13 patients who used insulin preoperatively required small amounts of insulin (mean 21 IU per day, range 15-30) to keep fasting and postprandial plasma glucose levels below 200 mg/dl. After 1 year, none of the patients used insulin or oral antidiabetic drugs. The HbA1c level decreased for the total patient population from 8.6% (range 5.8-12.1) preoperatively to 6.0% (range 4.3-7.8), 5.7% (range 4.1-7.6), and 5.6% (range 4.1-7.8) after 3, 6, and 12 months, respectively. The HbA1c levels at 1 year were significantly lower after BPD-DS and BPD than after RYGB (5.2%, range 4.1-6.4 versus 6.7%, range 5.8-7.8, p < 0.01, DHbA1c 1.4%, 95% confidence interval 0.5-2.4).

CONCLUSION

Metabolic intestinal bypass surgery for type 2 diabetes in low BMI patients is effective, with HbA1c levels at 1 year after the operation being significantly lower after BPD-DS or BPD than after RYGB.