Geltrude Mingrone

Bariatric surgery versus conventional medical therapy for type 2 diabetes

BACKGROUND Roux-en-Y gastric bypass and biliopancreatic diversion can markedly ameliorate diabetes in morbidly obese patients, often resulting in disease remission. Prospective, randomized trials comparing these procedures with medical therapy for the treatment of diabetes are needed. METHODS In this single-center, nonblinded, randomized, controlled trial, 60 patients between the ages of 30 and 60 years with a body-mass index (BMI, the weight in kilograms divided by the square of the height in meters) of 35 or more, a history of at least 5 years of diabetes, and a glycated hemoglobin level of 7.0% or more were randomly assigned to receive conventional medical therapy or undergo either gastric bypass or biliopancreatic diversion. The primary end point was the rate of diabetes remission at 2 years (defined as a fasting glucose level of <100 mg per deciliter [5.6 mmol per liter] and a glycated hemoglobin level of <6.5% in the absence of pharmacologic therapy). RESULTS At 2 years, diabetes remission had occurred in no patients in the medical-therapy group versus 75% in the gastric-bypass group and 95% in the biliopancreatic-diversion group (P<0.001 for both comparisons). Age, sex, baseline BMI, duration of diabetes, and weight changes were not significant predictors of diabetes remission at 2 years or of improvement in glycemia at 1 and 3 months. At 2 years, the average baseline glycated hemoglobin level (8.65±1.45%) had decreased in all groups, but patients in the two surgical groups had the greatest degree of improvement (average glycated hemoglobin levels, 7.69±0.57% in the medical-therapy group, 6.35±1.42% in the gastric-bypass group, and 4.95±0.49% in the biliopancreatic-diversion group). CONCLUSIONS In severely obese patients with type 2 diabetes, bariatric surgery resulted in better glucose control than did medical therapy. Preoperative BMI and weight loss did not predict the improvement in hyperglycemia after these procedures. (Funded by Catholic University of Rome; ClinicalTrials.gov number, NCT00888836.).

The Mechanism of Diabetes Control After Gastrointestinal Bypass Surgery Reveals a Role of the Proximal Small Intestine in the Pathophysiology of Type 2 Diabetes

Summary Background Data:Most patients who undergo Roux-en-Y gastric bypass (RYGB) experience rapid resolution of type 2 diabetes. Prior studies indicate that this results from more than gastric restriction and weight loss, implicating the rearranged intestine as a primary mediator. It is unclear, however, if diabetes improves because of enhanced delivery of nutrients to the distal intestine and increased secretion of hindgut signals that improve glucose homeostasis, or because of altered signals from the excluded segment of proximal intestine. We sought to distinguish between these two mechanisms. Methods:Goto-Kakizaki (GK) type 2 diabetic rats underwent duodenal-jejunal bypass (DJB), a stomach-preserving RYGB that excludes the proximal intestine, or a gastrojejunostomy (GJ), which creates a shortcut for ingested nutrients without bypassing any intestine. Controls were pair-fed (PF) sham-operated and untreated GK rats. Rats that had undergone GJ were then reoperated to exclude the proximal intestine; and conversely, duodenal passage was restored in rats that had undergone DJB. Oral glucose tolerance (OGTT), food intake, body weight, and intestinal nutrient absorption were measured. Results:There were no differences in food intake, body weight, or nutrient absorption among surgical groups. DJB-treated rats had markedly better oral glucose tolerance compared with all control groups as shown by lower peak and area-under-the-curve glucose values (P < 0.001 for both). GJ did not affect glucose homeostasis, but exclusion of duodenal nutrient passage in reoperated GJ rats significantly improved glucose tolerance. Conversely, restoration of duodenal passage in DJB rats reestablished impaired glucose tolerance. Conclusions:This study shows that bypassing a short segment of proximal intestine directly ameliorates type 2 diabetes, independently of effects on food intake, body weight, malabsorption, or nutrient delivery to the hindgut. These findings suggest that a proximal intestinal bypass could be considered for diabetes treatment and that potentially undiscovered factors from the proximal bowel might contribute to the pathophysiology of type 2 diabetes.

Bariatric surgery versus non-surgical treatment for obesity: a systematic review and meta-analysis of randomised controlled trials

Objective To quantify the overall effects of bariatric surgery compared with non-surgical treatment for obesity. Design Systematic review and meta-analysis based on a random effects model. Data sources Searches of Medline, Embase, and the Cochrane Library from their inception to December 2012 regardless of language or publication status. Eligibility criteria Eligible studies were randomised controlled trials with ≥6 months of follow-up that included individuals with a body mass index ≥30, compared current bariatric surgery techniques with non-surgical treatment, and reported on body weight, cardiovascular risk factors, quality of life, or adverse events. Results The meta-analysis included 11 studies with 796 individuals (range of mean body mass index at baseline 30-52). Individuals allocated to bariatric surgery lost more body weight (mean difference −26 kg (95% confidence interval −31 to −21)) compared with non-surgical treatment, had a higher remission rate of type 2 diabetes (relative risk 22.1 (3.2 to 154.3) in a complete case analysis; 5.3 (1.8 to 15.8) in a conservative analysis assuming diabetes remission in all non-surgically treated individuals with missing data) and metabolic syndrome (relative risk 2.4 (1.6 to 3.6) in complete case analysis; 1.5 (0.9 to 2.3) in conservative analysis), greater improvements in quality of life and reductions in medicine use (no pooled data). Plasma triglyceride concentrations decreased more (mean difference −0.7 mmol/L (−1.0 to −0.4) and high density lipoprotein cholesterol concentrations increased more (mean difference 0.21 mmol/L (0.1 to 0.3)). Changes in blood pressure and total or low density lipoprotein cholesterol concentrations were not significantly different. There were no cardiovascular events or deaths reported after bariatric surgery. The most common adverse events after bariatric surgery were iron deficiency anaemia (15% of individuals undergoing malabsorptive bariatric surgery) and reoperations (8%). Conclusions Compared with non-surgical treatment of obesity, bariatric surgery leads to greater body weight loss and higher remission rates of type 2 diabetes and metabolic syndrome. However, results are limited to two years of follow-up and based on a small number of studies and individuals. Systematic review registration PROSPERO CRD42012003317 (www.crd.york.ac.uk/PROSPERO).

Mechanisms of recovery from type 2 diabetes after malabsorptive bariatric surgery.

Currently, there are no data in the literature regarding the pathophysiological mechanisms involved in the rapid resolution of type 2 diabetes after bariatric surgery, which was reported as an additional benefit of the surgical treatment for morbid obesity. With this question in mind, insulin sensitivity, using euglycemic-hyperinsulinemic clamp, and insulin secretion, by the C-peptide deconvolution method after an oral glucose load, together with the circulating levels of intestinal incretins and adipocytokines, have been studied in 10 diabetic morbidly obese subjects before and shortly after biliopancreatic diversion (BPD) to avoid the weight loss interference. Diabetes disappeared 1 week after BPD, while insulin sensitivity (32.96 ± 4.3 to 65.73 ± 3.22 μmol · kg fat-free mass−1 · min−1 at 1 week and to 64.73 ± 3.42 μmol · kg fat-free mass−1 · min−1 at 4 weeks; P < 0.0001) was fully normalized. Fasting insulin secretion rate (148.16 ± 20.07 to 70.0.2 ± 8.14 and 83.24 ± 8.28 pmol/min per m2; P < 0.01) and total insulin output (43.76 ± 4.07 to 25.48 ± 1.69 and 30.50 ± 4.71 nmol/m2; P < 0.05) dramatically decreased, while a significant improvement in β-cell glucose sensitivity was observed. Both fasting and glucose-stimulated gastrointestinal polypeptide (13.40 ± 1.99 to 6.58 ± 1.72 pmol/l at 1 week and 5.83 ± 0.80 pmol/l at 4 weeks) significantly (P < 0.001) decreased, while glucagon-like peptide 1 significantly increased (1.75 ± 0.16 to 3.42 ± 0.41 pmol/l at 1 week and 3.62 ± 0.21 pmol/l at 4 weeks; P < 0.001). BPD determines a prompt reversibility of type 2 diabetes by normalizing peripheral insulin sensitivity and enhancing β-cell sensitivity to glucose, these changes occurring very early after the operation. This operation may affect the enteroinsular axis function by diverting nutrients away from the proximal gastrointestinal tract and by delivering incompletely digested nutrients to the ileum.

Glucagon-like peptide-1 receptor activation stimulates hepatic lipid oxidation and restores hepatic signalling alteration induced by a high-fat diet in nonalcoholic steatohepatitis.

Background/Aims: High‐fat dietary intake and low physical activity lead to insulin resistance, nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH). Recent studies have shown an effect of glucagon‐like peptide‐1 (GLP‐1) on hepatic glucose metabolism, although GLP‐1 receptors (GLP‐1r) have not been found in human livers. The aim of this study was to investigate the presence of hepatic GLP‐1r and the effect of exenatide, a GLP‐1 analogue, on hepatic signalling.

Glucagon-like peptide-1 receptor activation stimulates hepatic lipid oxidation and restores hepatic signalling alteration induced by a high-fat diet in nonalcoholic steatohepatitis

Background/Aims: High‐fat dietary intake and low physical activity lead to insulin resistance, nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH). Recent studies have shown an effect of glucagon‐like peptide‐1 (GLP‐1) on hepatic glucose metabolism, although GLP‐1 receptors (GLP‐1r) have not been found in human livers. The aim of this study was to investigate the presence of hepatic GLP‐1r and the effect of exenatide, a GLP‐1 analogue, on hepatic signalling.

Effects of dietary fatty acids on insulin sensitivity and secretion

Globalization and global market have contributed to increased consumption of high‐fat, energy‐dense diets, particularly rich in saturated fatty acids( SFAs). Polyunsaturated fatty acids (PUFAs) regulate fuel partitioning within the cells by inducing their own oxidation through the reduction of lipogenic gene expression and the enhancement of the expression of those genes controlling lipid oxidation and thermogenesis. Moreover, PUFAs prevent insulin resistance by increasing membrane fluidity and GLUT4 transport. In contrast, SFAs are stored in non‐adipocyte cells as triglycerides (TG) leading to cellular damage as a sequence of their lipotoxicity. Triglyceride accumulation in skeletal muscle cells (IMTG) derives from increased FA uptake coupled with deficient FA oxidation. High levels of circulating FAs enhance the expression of FA translocase the FA transport proteins within the myocites. The biochemical mechanisms responsible for lower fatty acid oxidation involve reduced carnitine palmitoyl transferase (CPT) activity, as a likely consequence of increased intracellular concentrations of malonyl‐CoA; reduced glycogen synthase activity; and impairment of insulin signalling and glucose transport. The depletion of IMTG depots is strictly associated with an improvement of insulin sensitivity, via a reduced acetyl‐CoA carboxylase (ACC) mRNA expression and an increased GLUT4 expression and pyruvate dehydrogenase (PDH) activity. In pancreatic islets, TG accumulation causes impairment of insulin secretion. In rat models, β‐cell dysfunction is related to increased triacylglycerol content in islets, increased production of nitric oxide, ceramide synthesis and β‐cell apoptosis. The decreased insulin gene promoter activity and binding of the pancreas‐duodenum homeobox‐1 (PDX‐1) transcription factor to the insulin gene seem to mediate TG effect in islets. In humans, acute and prolonged effects of FAs on glucose‐stimulated insulin secretion have been widely investigated as well as the effect of high‐fat diets on insulin sensitivity and secretion and on the development of type 2 diabetes.

Reversibility of insulin resistance in obese diabetic patients: role of plasma lipids

Summary The aim of the present study was to measure whole body glucose uptake (M) and oxidation rate by euglycaemic hyperinsulinaemic clamp and indirect calorimetry in 7 morbidly obese subjects (BMI > 40 kg/m2) at three time points: before bilio-pancreatic diversion (BPD) surgery (Ob); 3 months after surgery (POI); and after reaching stable body weight, at least 2 years after surgery (POII). A group of 7 control subjects (C), matched groupwise for sex, age and BMI with POII patients, was also studied. The M value at POI was significantly higher than at Ob (49.12 ± 8.57 vs 18.14 ± 8.57 μmol · kg−1· min−1). No statistical difference was observed between the POII and C groups. Similarly, glucose oxidation rate was significantly increased at POI with respect to Ob (24.2 ± 7.23 vs 9.42 ± 3.91 μmol · kg−1· min−1) and was not significantly different between POII and C. Basal levels of non-esterified fatty acids (NEFA) decreased significantly both from Ob to POI and from POI to POII (1517.1 ± 223.9 vs 1039.6 ± 283.4 vs 616.0 ± 77.6 μmol · l−1). The same applied to basal plasma triglycerides (2.07 ± 0.77 vs 1.36 ± 0.49 vs 0.80 ± 0.19 g · l−1). Weight decreased mainly in the late postoperative period (POI to POII 124.28 ± 11.22 to 69.71 ± 11.78, 83 % of total decrement), rather than in the early postoperative period (Ob to POI 135.25 ± 14.99 to 124.28 ± 11.22 kg, 17 % of total decrement). We also report the clinical case of a young woman of normal weight, who underwent BPD for chylomicronaemia (secondary to familial lipoprotein lipase deficiency), whose M value, plasma insulin and blood glucose levels were normalized upon normalization of serum NEFA and triglyceride levels as determined by the therapeutic lipid malabsorption. In conclusion, in obese diabetic patients lipid malabsorption induced by BPD causes a definite enhancement of insulin sensitivity and glucose tolerance. This improvement in metabolism is noticeable before the surgery has major effects on body weight. These observations suggest that lowered plasma lipids, rather than weight loss per se, are the cause of the reversibility of insulin resistance. [Diabetologia (1997) 40: 599–605]

Impact of Different Bariatric Surgical Procedures on Insulin Action and β-Cell Function in Type 2 Diabetes

The prevalence of obesity appears to have reached a plateau in the U.S. between 2003 and 2007 (1), but the obesity epidemic is still rampant in many other countries—especially in the developing world (2)—in adults as well as children (http://www.who.int/topics/obesity/en/). A recent analysis of a large prospective cohort of individuals 50–71 years old (3) has generated a precise dose-response gradient for the positive association of BMI and relative risk of death independent of other risk factors (especially smoking and preexisting disease, which cause weight loss). Yet, long-term observational studies have generally found that weight loss, whether spontaneous or intentional, is associated with increased, rather than decreased, overall mortality (rev. in 4). Lifestyle intervention (diet and exercise), behavioral management, and drug therapy for obesity deliver a degree of weight loss that is usually modest (and therefore unattractive to patients) and short-lived (6 months to 1 year at best) and carry considerable side effects. Moreover, despite the attenuation of risk factors such as diabetes and dyslipidemia, trial evidence for an effect of these weight-control approaches on reducing cardiovascular disease or mortality is still lacking (rev. in 5). On the other hand, and perhaps as a consequence, surgery for the treatment of severe obesity is gaining increasing favor. The annual U.S. frequency of hospital discharges that included bariatric surgery increased sevenfold (from 3.5 to 24.0 per 100,000) between 1996 and 2002 (6). According to a review of 85,048 morbidly obese patients (7), early (≤30 days) and late (30 days to 2 years) mortality rates for bariatric surgery trend downward (0.28 and 0.35%, respectively). Surgical treatment of massive obesity is being extended to adolescents, seemingly with similar success and risk rates as in adults (8–10). Recently, the 10.9-year follow-up of the Swedish Obese Subjects Study reported a 30% risk reduction for …

Gut microbiome-derived metabolites characterize a peculiar obese urinary metabotype

Obesity is a complex multifactorial disease involving genetic and environmental factors and influencing several different metabolic pathways. In this regard, metabonomics, that is the study of complex metabolite profiles in biological samples, may provide a systems approach to understand the global metabolic regulation of the organism in relation to this peculiar pathology. In this pilot study, we have applied a nuclear magnetic resonance (NMR)-based metabolomic approach on urinary samples of morbidly obese subjects. Urine samples of 15 morbidly obese insulin-resistant (body mass index>40; homeostasis assessment model of insulin resistance>3) male patients and 10 age-matched controls were collected, frozen and analyzed by high-resolution 1H-NMR spectroscopy combined with partial least squares-discriminant analysis. Furthermore, two obese patients who underwent bariatric surgery (biliopancreatic diversion and gastric bypass, respectively) were monitored during the first 3 months after surgery and their urinary metabolic profiles were characterized. NMR-based metabolomic analysis allowed us to identify an obesity-associated metabolic phenotype (metabotype) that differs from that of lean controls. Gut flora-derived metabolites such as hippuric acid, trigonelline, 2-hydroxyisobutyrate and xanthine contributed most to the classification model and were responsible for the discrimination. These preliminary results confirmed that in humans the gut microflora metabolism is strongly linked to the obesity phenotype. Moreover, the typical obese metabotype is lost after weight loss induced by bariatric surgery.