Effects of Agonists of Glucagon Like Peptide - 1 Receptors (GLP-1R) on Arterial Stiffness, Endothelial Glycocalyx and Coronary Flow Reserve in Patients With Coronary Artery Disease and Patients With Diabetes Mellitus
Phase: NA
Conditions: Type 2 Diabetes Mellitus, Coronary Artery Disease
Sponsor: University of Athens

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Effects of agonists of glucagon like peptide - 1 receptors (GLP-1R) on
arterial  stiffness,  endothelial  glycocalyx  and  coronary  flow  reserve  in
patients with coronary artery disease and patients with diabetes mellitus  
ClinicalTrials.gov Identifier: NCT03010683
Document date: December 22, 2016
Study Protocol
Objectives
Arterial stiffness is associated with increased risk for cardiovascular disease.
Moreover, the integrity of endothelial glycocalyx plays a vital role in vascular
permeability, inflammation and elasticity. Agonists of glucagon like peptide - 1
receptors (GLP-1R) used in the treatment of type 2 diabetes mellitus (T2DM).
This category includes exenatide and liraglutide. These drugs lower glucose
levels by inhibiting the secretion of glucagon, promoting the release of insulin in
response to hyperglycemia, slowing gastric emptying, and augmenting satiety.
Clinical studies have shown that GLP-1R agonists have beneficial effects on
cardiovascular  function  in  both  diabetic  patients  and  healthy  subjects.  The
purpose of this study is to investigate in patients with T2DM without coronary
artery disease (CAD), patients with T2DM and CAD and obese patients with
abnormal  oral  glucose  tolerance  test  (OGTT),  changes  in  arterial  stiffness,

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endothelial  glycocalyx  thickness  and  coronary  reserve  flow  (CFR)  after
treatment with metformin or agonist GLP-1R.
Design
The investigators will study three groups matched for age and sex: 30 patients
with type 2 diabetes mellitus (T2DM) without coronary artery disease (CAD), 30
patients  with  T2DM  and  CAD  and  30  obese  patients  (BMI  >30  Kg/m²)  with
abnormal oral glucose tolerance test (OGTT). It will be a randomized study with
metformin or GLP-1R agonist treatment for 1 year. All subjects will receive for 1
year: (a) GLP-1R agonist or (b) metformin. At 0, 3, 6 and 12 months, where 0 is
the starting point of treatment, blood samples will be collected.
Methods
At 0, 3, 6 and 12 months the investigators will measure:
a. Carotid-femoral pulse wave velocity (PWV, m/sec) using tonometry by
Complior (SP ALAM) and augmentation index (AI, %) by the method of
arteriography (Arteriograph, TensioMed)
b. Perfused boundary region (PBR, micrometers) of the sublingual arterial
microvessels (ranged from 5-25 micrometers) using Sideview Darkfield
imaging  (Microscan,  Glycocheck).  Increased  PBR  is  considered  an
accurate noninvasive index of reduced endothelial glucocalyx thickness.
c. Coronary flow reserve (CFR) in the left anterior descending artery after
infusion of adenosine using Doppler echocardiography.
d. Determination of the following parameters in blood: glucose, insulin, free
fatty acids, triglycerides, glycerol, C reactive protein (CRP), transforming

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growth factor-b (TGF-b), Lipoprotein-Associated Phospholipase A2 (LP-
LPA2), tumor necrosis factor-a (TNF-a), interleukins 6 and 10 (IL6 and
IL10), propeptide of type I procollagen (PIP), propeptide of procollagen
type III (PIIINP), matrix metallopeptidases 9 and 2 (MMP), macrophage-
colony stimulating factor (MCSF), growth differentiation factor-15 (GDF-
15), N-terminal pro b-type natriuretic peptide (NT-proBNP) and galectin-
3.
Statistical analysis
All  comparisons  will  be  performed  with  the  Statistical  Package  for  Social
Sciences 21.0 for Windows (SPSS Inc., Chicago, Illinois, USA). Categorical
data  will  be  compared  between  patients  by  contingency  tables.  Continuous
variables  will  be  tested  for  normality  using  the  Kolmogorov-Smirnov  test.
Normally distributed variables will be given as mean±standard deviation. Data
with  a  non-gaussian  distribution  will  be  expressed  as  median  (interquartile
range)  and  will  be  analyzed  after  transformation  into  ranks.  Differences  in
mean values for each of the measured variables will be compared by t-test or
paired t-test for continuous variables. For non-normally distributed data Mann
Whitney or Wilcoxon signed-rank test will be used. The investigators will use
parametric  (Pearson  r)  and  non-parametric  (Spearman  rho)  correlation
coefficients to examine cross-sectional associations. ANOVA (general linear
model, SPSS 22, SPSS Inc, Chicago, Ill) for repeated measurements will be
applied a) for measurements of the examined markers at baseline, 3, 6 and 12
months  after  treatment  used  as  a  within-subject  factor  b)  for  the  effects  of
treatment (liraglutide vs metformin), as a between-subject factors. The F and P

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values  of  the  interaction  between  time  of  measurement  of  the  examined
markers and type of treatment will be calculated. The F and P values of the
comparison between treatments will be calculated. The Greenhouse-Geisser
correction  will  be  used  when  the  sphericity  assumption,  as  assessed  by
Mauchly’s test, will not be met. Post hoc comparisons will be performed with
Bonferroni correction.
Comparisons between baseline or post-treatment values of measured markers
between the 2 treatment groups will be performed using factorial ANOVA. Post
hoc  comparisons  will  be  performed  with  Bonferroni  correction.  Statistical
significance  will  be  considered  as  p<0.05.  Baseline  variables  that  will  be
statistically different (p<0.05) among the 2 study groups or will be of clinical
significance (HbA1c, weight, BMI and waist circumference) will be included in
multivariate models as covariates.