Advertisement

Topics

A Longitudinal Study on Short-term Effects of Gastric Bypass on Glucose Homeostasis in Obesity

2014-07-23 21:10:50 | BioPortfolio

Summary

The purpose of this study is to quantify the relative contribution of improved insulin sensitivity and improved insulin secretion to the glycaemic effect of bariatric surgery.

Description

In 1987 Pories et al. (1) published that after gastric bypass 99% of morbidly obese patients became and remained euglycaemic over time. However, the most interesting observation of these authors (1) was that the patients were converted to euglycaemia within 10 days of the operation, even if before they required large doses of insulin. Thereafter, we ourselves (2-6) as well as other Authors (7,8) have found that both mainly malabsorptive bariatric and mainly restrictive surgery are effective in producing early improvement/resolution of type 2 diabetes, also in normal weight (9) or overweight-obese subjects (10).

Until now the mechanisms through which bariatric surgery operate in improving insulin sensitivity and, consequently, diabetes control have not been elucidated. To complicate the picture there is the fact that after bariatric surgery patients are not allowed to eat for a time that is longer as the entity of the abdominal trauma increases. In fact, after laparoscopic bariatric surgery the patients are re-alimented in the 3rd post-operative day while after open surgery the time length before re-alimentation is about 7 days. Although in most centres the patients receive a parenteral nutrition covering the energy needs while they remain at rest, in some other centres they are only re-hydrated. Thus, it might be hypothesised that fasting can contribute to the improvement of glucose disposal. The data in the literature counteract this possibility as many Authors (11-15) have demonstrated that a very-low calorie diet (VLCD) is essentially unable to improve insulin sensitivity at least in the short run, when the weight loss is minimal. In this regard, Jazet et al. (11) found that the glucose control amelioration in diabetic subjects undergoing a 2-day VLCD was a reduction in the hepatic glucose production rather than an improvement in the whole-body glucose disposal. Similarly, Christiansen et al (12) observed the increase in the glucose metabolic clearance rate (MCR) was not apparent before day 20 of energy restriction, when the weight loss became significant. In another study, diabetic patients under a 4-day energy-restricted diet (providing 4620 ± 1050 kJ/d) had a deterioration of both basal glucose MCR and insulin-stimulated glucose disposal (13).

Recently, Laferrère et al (16) compared the late (1 month) effect of an equivalent weight loss by RYGB or by diet in two groups of matched morbidly obese patients with type 2 diabetes mellitus. The glucose area under-the-curve (AUC) after an oral glucose tolerance test (OGTT) and glucose levels at 120' were significantly lower after RYGB compared with diet (P = 0.014 and P = 0.001, respectively).

Another important aspect of the weight loss is the modulation of lipolysis. Many studies have shown that obese subjects are insulin resistant at the level of adipose tissue, ie, despite high plasma insulin levels lipolysis and FFA release are not suppressed. It is therefore interesting to study the changes in lipolysis before and after surgery and also the ability of insulin (e.g., during the euglycemic, hyperinsulinemic clamp) to suppress peripheral lipolysis. By infusing deuterated glycerol we will be able to estimate glycerol rate of appearance, which is the best available index of lipolysis. In fact intracellular triglyceride (TG) hydrolysis results in the release of one mole of glycerol and 3 moles of FFA. While the FFA can be re-esterified intracellularly, and thus do not appear into the systemic circulation, glycerol cannot be re-esterified since the adipocyte lacks glycerol kinase. Thus, all glycerol derived from intracellular TG hydrolysis is released into the circulation and can be traced by deuterated glycerol. We have used this technique previously in diabetic subjects (17), in subjects with NASH as well as in obese subjects under VLCD (18). In the latter study we have shown that VLCD improved adipose tissue IR.

As far as we know, no data are available in the literature comparing the effect of RYGB with a purely restrictive bariatric procedure in order to take into account simultaneously the effect of the surgical trauma and that of the reduced food intake in the early post-operative period.

The main goal of this study is to determine the immediate effect of Roux-en-Y gastric bypass surgery on glucose homeostasis, factoring out the confounding effects of the surgical approach (incl. laparoscopy) and of the post-operative fasting.

To this purpose, patients of the two bariatric surgery groups (Roux-en-Y gastric bypass and gastric banding) are matched as far as feasible. Primary parameter is insulin resistance (as assessed by Matsuda index). Further the same BMI inclusion criteria apply for both groups (BMI > 30 kg/m2 and < 55 kg/m2). While age, gender and BMI within the specified range are also expected to influence the read-outs, no matching for these baseline characteristics is foreseen due to feasibility issues.

Patients receive oral food typically from day 3 or 4 after laparoscopic bariatric surgery. This post-operative food intake is restricted to 800 - 1000 kcal/day, usually divided in 6 small meals, with the following composition 55% carbohydrates, 30% lipids and 15% proteins; saturated lipids ~ 10% . A similar caloric intake restriction will be imposed during the 1-week diet period prior to Visit 3, which will be done 10 +/- 2 weeks before the operation in order to allow the patients a complete recovery of his/her body weight which must be kept constant before the next study in order to avoid methodological biases.

Study Design

Time Perspective: Prospective

Conditions

Morbid Obesity

Intervention

Study on insulin sensitivity after diet or bariatric surgery, gastric bypass

Location

Department of Internal Medicine, Catholic University
Rome
Italy
00168

Status

Not yet recruiting

Source

Catholic University of the Sacred Heart

Results (where available)

View Results

Links

Published on BioPortfolio: 2014-07-23T21:10:50-0400

Clinical Trials [3911 Associated Clinical Trials listed on BioPortfolio]

Surgical Removal of Visceral Fat Tissue (Omentectomy) Associated to Bariatric Surgery: Effects on Insulin Sensitivity

The intraabdominal fat is associated with insulin resistance, a condition that is in the basis of diabetes, metabolic syndrome and some cardiovascular diseases. It is not clear whether it ...

Bariatric Surgery and Weight Loss on Energy Metabolism and Insulin Sensitivity

The purpose of the study is to determine the effect of three weight loss surgeries compared to a low calorie diet with regard to energy expenditure, body composition, insulin sensitivity, ...

Proteomics in Morbid Obesity After Bariatric Surgery

Glycemic control is rapidly restored in patients with insulin resistance after bariatric surgery, in particular after the mal-absorptive one (i.e. Bilio-pancreatic diversion, BPD). To ev...

Early Changes of Diabetes Parameters After Obesity Therapy

The aim of the study is to investigate, if bariatric surgery or the related caloric restriction causes the significant improvement of glucose metabolism, which has been found in bariatric ...

Micro-nutritional Status and Gut Microbiota in Morbidly Obese Patients Before and After Gastric Bypass

An intervention study design in 90 obese patients will be used. Nutritional, metabolic and psychological status as well as gut microbiota will be evaluated before gastric bypass and 6 mont...

PubMed Articles [28162 Associated PubMed Articles listed on BioPortfolio]

Laparoscopic adjustable gastric banding in adolescents with severe obesity: Psychological aspects, decision makers of surgery, and 2-year outcomes. A case series.

The results of medical treatment of severe obesity in the adolescent population (balanced diet and physical activity) are often unsatisfactory, and bariatric surgery is questioned. The psychological d...

Concurrent bariatric surgery and paraesophageal hernia repair: comparison of sleeve gastrectomy and Roux-en-Y gastric bypass.

Paraesophageal hernia (PEH) is a common condition that bariatric surgeons encounter. Expert opinion is split on whether bariatric surgery and PEH repair should be completed concurrently or sequentiall...

Cross-Talk Between Bile Acids and Gastro-Intestinal and Thermogenic: Clues from Bariatric Surgery.

Obesity is rapidly increasing and has reached epidemic features worldwide. It´s linked to insulin resistance, systemic low-grade inflammation and common pathogenic pathways with a number of comorbidi...

The role of glucagon in weight loss-mediated metabolic improvement: a systematic review and meta-analysis.

Aims This meta-analysis aimed to investigate the role of glucagon suppression in regulating glucose homeostasis following diet or bariatric surgery. Methods A comprehensive search of intervention and ...

Bariatric Surgery and the Incidence of Psoriasis and Psoriatic Arthritis in the Swedish Obese Subjects Study.

The aim of this study was to assess the effect of bariatric surgery (vertical gastroplasty, gastric banding, or gastric bypass) compared with usual care on the incidence of psoriasis and psoriatic art...

Medical and Biotech [MESH] Definitions

Activities related to WEIGHT REDUCTION in patients with OBESITY. Treatment methods include DIET; EXERCISE; BEHAVIOR MODIFICATION; medications; and BARIATRIC SURGERY.

Surgical procedures aimed at producing major WEIGHT REDUCTION in patients with MORBID OBESITY.

A gastrointestinal peptide hormone of about 43-amino acids. It is found to be a potent stimulator of INSULIN secretion and a relatively poor inhibitor of GASTRIC ACID secretion.

A biguanide hypoglycemic agent used in the treatment of non-insulin-dependent diabetes mellitus not responding to dietary modification. Metformin improves glycemic control by improving insulin sensitivity and decreasing intestinal absorption of glucose. (From Martindale, The Extra Pharmacopoeia, 30th ed, p289)

That portion of the stomach remaining after gastric surgery, usually gastrectomy or gastroenterostomy for cancer of the stomach or peptic ulcer. It is a common site of cancer referred to as stump cancer or carcinoma of the gastric stump.

More From BioPortfolio on "A Longitudinal Study on Short-term Effects of Gastric Bypass on Glucose Homeostasis in Obesity"

Advertisement
Quick Search
Advertisement
Advertisement

 

Relevant Topic

Obesity
Obesity is the condition in which excess fat has accumulated in the body (mostly in subcutaneous tissues). clinical obesity is considered to be present when a person has a BMI of over 30 (Oxford Dictionary of Medicine). It is becoming increasing common i...


Searches Linking to this Trial