Glucagon-like peptide-1 (GLP-1) receptor agonists are a relatively new treatment option for obesity and type 2 diabetes. Treatment has been shown to result in in weight loss and improved glycemic... Show moreGlucagon-like peptide-1 (GLP-1) receptor agonists are a relatively new treatment option for obesity and type 2 diabetes. Treatment has been shown to result in in weight loss and improved glycemic control. In this thesis, the effects of treatment on the different adipose tissue depots and on cardiac function are described. In a randomised controlled trial, we treated patients with type 2 diabetes from South Asian descent, a population with increased risk to develop type 2 diabetes and cardiovascular disease compared to Western Europeans, with liraglutide, a GLP-1 receptor agonist, or placebo, and studied these subjects with MRI. We concluded that liraglutide and possibly other GLP-1 receptor agonists can be a good strategy to reduce the volume of visceral adipose tissue. This reduction was accompanied by a significant improvement of glycemic control. Lastly, we provided evidence that liraglutide does not improve cardiac function and myocardial tissue characteristics and thus does not improve diabetic cardiomyopathy. In addition, in another study, we studied the mechanism behind GLP-1 receptor agonism induced weight loss and concluded that liraglutide induces weight loss in humans by decreasing energy intake rather than by activating brown adipose tissue or increasing energy expenditure. Show less
Aims/hypothesis The aim of this work was to assess the effect of liraglutide on ectopic fat accumulation in individuals with type 2 diabetes mellitus. Methods This study is a pre-specified... Show moreAims/hypothesis The aim of this work was to assess the effect of liraglutide on ectopic fat accumulation in individuals with type 2 diabetes mellitus. Methods This study is a pre-specified subanalysis of the MAGNetic resonance Assessment of VICTOza efficacy in the Regression of cardiovascular dysfunction In type 2 diAbetes mellitus (MAGNA VICTORIA) study, with primary endpoints being the effects of liraglutide on left ventricular diastolic and systolic function. The MAGNA VICTORIA study was a single-centre, parallel-group trial in 50 individuals with type 2 diabetes mellitus (BMI >25 kg/m(2)) who were randomly assigned (1:1, stratified for sex and insulin use) to receive liraglutide 1.8 mg once daily or placebo for 26 weeks, added to standard care. Participants, study personnel and outcome assessors were blinded to treatment allocation. The secondary endpoints of visceral adipose tissue (VAT), abdominal subcutaneous adipose tissue (SAT) and epicardial fat were measured with MRI. Hepatic triacylglycerol content (HTGC) and myocardial triacylglycerol content (MTGC) were quantified with proton MR spectroscopy. Between-group differences (change from baseline) were tested for significance using ANCOVA. Mean differences with 95% CIs were reported. Results The trial was completed in 2016. Twenty-four participants were randomised to receive liraglutide and 26 to receive placebo. One patient in the liraglutide group withdrew consent before having received the study drug and was not included in the intention-to-treat analysis. Liraglutide (n = 23) vs placebo (n = 26) significantly reduced body weight (liraglutide 98.4 +/- 13.8 kg to 94.3 +/- 14.9 kg; placebo 94.5 +/- 13.1 kg to 93.9 +/- 13.2 kg; estimated treatment effect -4.5 [95% CI -6.4, -2.6] kg). HbA(1c) declined in both groups without a significant treatment effect of liraglutide vs placebo (liraglutide 66.7 +/- 11.5 mmol/mol to 55.0 +/- 13.2 mmol/mol [8.4 +/- 1.1% to 7.3 +/- 1.2%]; placebo 64.7 +/- 10.2 mmol/mol to 56.9 +/- 6.9 mmol/mol [8.2 +/- 1.0% to 7.5 +/- 0.7%]; estimated treatment effect -2.9 [95% CI -8.1, 2.3] mmol/mol or -0.3 [95% CI -0.8, 0.2]%). VAT did not change significantly between groups (liraglutide 207 +/- 87 cm(2) to 203 +/- 88 cm(2); placebo 204 +/- 63 cm(2) to 200 +/- 55 cm(2); estimated treatment effect -7 [95% CI -24, 10] cm(2)), while SAT was reduced by a significantly greater extent with liraglutide than with placebo (liraglutide 361 +/- 142 cm(2) to 339 +/- 131 cm(2); placebo 329 +/- 107 cm(2) to 333 +/- 125 cm(2); estimated treatment effect -29 [95% CI -51, -8] cm(2)). Epicardial fat did not change significantly between groups (liraglutide 8.9 +/- 4.3 cm(2) to 9.1 +/- 4.7 cm(2); placebo 9.6 +/- 4.1 cm(2) to 9.6 +/- 4.6 cm(2); estimated treatment effect 0.2 [95% CI -1.5, 1.8] cm(2)). Change in HTGC was not different between groups (liraglutide 18.1 +/- 11.2% to 12.0 +/- 7.7%; placebo 18.4 +/- 9.4% to 14.7 +/- 10.0%; estimated treatment effect -2.1 [95% CI -5.3, 1.0]%). MTGC was not different after treatment with liraglutide (1.5 +/- 0.6% to 1.2 +/- 0.6%) vs placebo (1.3 +/- 0.5% to 1.2 +/- 0.6%), with an estimated treatment effect of -0.1 (95% CI -0.4, 0.2)%. There were no adjudicated serious adverse events. Conclusions/interpretation Compared with placebo, liraglutide-treated participants lost significantly more body weight. Liraglutide primarily reduced subcutaneous fat but not visceral, hepatic, myocardial or epicardial fat. Future larger studies are needed to confirm the results of this secondary endpoint study. Funding This study was funded by Novo Nordisk A/S (Bagsvaerd, Denmark). Show less
The studies described in this thesis explored the effects of nutritional, exercise and pharmacological interventions on ectopic triglyceride accumulation in obese patients and/or patients with type... Show moreThe studies described in this thesis explored the effects of nutritional, exercise and pharmacological interventions on ectopic triglyceride accumulation in obese patients and/or patients with type 1 or type 2 diabetes mellitus (T2DM). Ectopic fat is defined as triglyceride (TG) storage in tissues, other than adipose tissue, such as the liver, heart and skeletal muscle. The focus of this thesis is on ectopic fat accumulation in two important organs: the liver and the heart. Studies in current thesis indeed have shown that lifestyle and pharmacological interventions can change ectopic triglyceride accumulation in (advanced) T2DM and is associated with changes in function. However, the notion emerges that the different fat compartments have differential regulation in relation to exercise, nutrition and pharmacological interventions. This points to different regulatory mechanisms involved in the accumulation and/or lipolysis of these fat compartments. Alternatively, it is possible that similar mechanisms are involved but with different dose-response relationships. These cannot be derived from the studies described in the current thesis because the aims of these studies were not focussed at these mechanisms underlying the dynamics of the individual fat depots. As patients with obesity and T2DM may have different ectopic fat distribution, this may also affect their (cardiac) risk profile. Manchann et al. already studied the effect of lifestyle intervention versus antidiabetic medication in patients with different fat distribution and found that this could predict intervention failure. More studies in these dynamics will hopefully lead to understanding from which treatments specific patient groups will benefit most. Show less
