Improvement in myocardial energetics and perfusion with Liraglutide in patients with type 2 diabetes- A randomised, single centre, open label, cross-over drug trial
Authors: Chowdhary A , Thirunavukarasu S , Jex N , Kotha S , Giannoudi M , Proctor H , Kellman P , Greenwood J P , Plein S , Levelt E 
Published: November 2023

Abstract

Background
Both the insulin secretion and insulin resistance in Type 2 diabetes (T2D) are amenable to pharmacological intervention. In a single center, open-label, randomized, cross-over design trial we sought to compare two distinct glycaemic control strategies of targeting beta-cell dysfunction and promoting insulin secretion using Glucagon-like peptide-1 receptor agonists (GLP-1RA) -liraglutide and targeting peripheral insulin resistance using a peroxisome proliferator activated receptor-gamma agonist (PPAR-g)-pioglitazone to see which results in greater improvements in myocardial perfusion, energetics and function in patients with T2D.

Methods
Fifty-two T2D patients were screened. Eligible patients with no known prior cardiovascular disease were randomized in a 1:1 ratio to be administered one of the study drugs for a 16-week treatment period followed by an 8-week washout and a further 16-week treatment period for the second drug. Thirty-three eligible participants completed both treatment periods. Participants have undergone 31phosphorus magnetic resonance spectroscopy (31P-MRS) at rest and dobutamine stress followed by the cardiac magnetic resonance (CMR) scans. The CMR protocol consisted of rest and dobutamine stress cine imaging, perfusion imaging (motion corrected, automated in-line perfusion mapping), velocity-encoded mitral in-flow imaging and late gadolinium enhanced imaging at 3T immediately before commencement and after completion of each treatment arm (four scans per participant).

Results
Clinical and biochemical characteristics, and CMR/31P-MRS results are provided in Tables 1&2 respectively. Liraglutide therapy resulted in a significant reductions in the body mass index and significant improvements in glycemic control. Both drugs reduced insulin resistance indicated by a reduction in the mean triglyceride index. There were no significant changes in NTproBNP or troponin levels with either drug.
Therapy with either drug did not result in a significant change in the LV end-diastolic volume, ejection fraction or global longitudinal shortening. Pioglitazone led to a significant increment in mean LV mass and LV mass index, while no significant effect in myocardial mass or mass index were detected with liraglutide.
Liraglutide therapy resulted in increased rest and dobutamine stress energetics, global stress myocardial blood flow and myocardial perfusion reserve index. While pioglitazone treatment showed no significant effect in these parameters, an isolated improvement in the rest diastolic function was detected in this arm.

Conclusions
In this randomised cross-over design trial we showed for the first time that four months treatment with glucagon like protein 1 receptor agonist liraglutide results in significant improvements in myocardial stress perfusion and energetics. Pioglitazone results in an isolated improvement in rest diastolic funct