The study seeks to explore the cardiovascular effects of co-agonism at two peptide receptors, GLP-1 and glucagon. Glucagon, exenatide and 0.9% saline will be intravenously infused, both in isolation, and combination into healthy male participants. Overall, the aim of the study is to further our understanding on the role these endogenous substances play (both in isolation and combination) in haemodynamic regulation.
Co-agonist peptides (such as at the GLP-1:glucagon receptor) are currently in clinical development for type 2 diabetes with the dual intention of reducing body weight and controlling blood glucose. However, there is a lack of data on the effects that co-agonism has on haemodynamic regulation. Part A - Healthy male participants, by acting as their own control, will attend for two intravenous infusion visits (combination of 0.9% saline and glucagon). These will occur in a predefined but random order so that participants will be blinded to the infusion they are receiving. Each infusion visit will comprise of 15 minute baseline followed by a 120 minute infusion. Detailed non-invasive cardiovascular measurements (including peripheral/central blood pressure, heart rate, stroke volume, heart rate variability) and bloods (including insulin, glucose, GLP-1, glucagon) will be collected as part of the study. It was previously planned that GLP-1 7-36 amide 0.6pmol/kg/min and 1.2pmol/kg/min would be infused for Part A resulting in 5 infusions (rather than current 2 infusions). However due to supply/technical issues this was not possible and therefore exenatide (GLP-1 receptor agonist) shall be used in Part B. Part B - Healthy male participants, by acting as their own control, will attend for four intravenous infusion visits (combination of 0.9% saline, glucagon, exenatide). These will occur in a predefined but random order so that participants will be blinded to the infusion they are receiving. Each infusion visit will comprise of 15 minute baseline followed by a 60 minute infusion. Detailed non-invasive cardiovascular measurements (including peripheral/central blood pressure, heart rate, stroke volume, heart rate variability) and bloods (including insulin, glucose, GLP-1, glucagon) will be collected as part of the study.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
SINGLE
Enrollment
26
Intravenous infusion of 0.9% saline
Intravenous infusion of glucagon 25ng/kg/min
Intravenous infusion of glucagon 50ng/kg/min
Addenbrooke's Hospital
Cambridge, Cambridgeshire, United Kingdom
Changes in haemodynamic parameters following intravenous infusion of 0.9% saline, glucagon, exenatide and their combination.
Heart rate (bpm)
Time frame: Comparison between 2 hour infusion visit 1-2 (Part A) / 1 hour infusion visit 1-4 (Part B), over a maximum period of 15 weeks
Changes in haemodynamic parameters following intravenous infusion of 0.9% saline, glucagon, exenatide and their combination.
Brachial systolic and diastolic blood pressure (mmHg)
Time frame: Comparison between 2 hour infusion visit 1-2 (Part A) / 1 hour infusion visit 1-4 (Part B), over a maximum period of 15 weeks
Changes in haemodynamic parameters following intravenous infusion of 0.9% saline, glucagon, exenatide and their combination.
Central systolic and diastolic blood pressure and mean arterial pressure (mmHg) measured with SphygmoCor XCEL
Time frame: Comparison between 2 hour infusion visit 1-2 (Part A) / 1 hour infusion visit 1-4 (Part B), over a maximum period of 15 weeks
Changes in haemodynamic parameters following intravenous infusion of 0.9% saline, glucagon, exenatide and their combination.
Stroke volume (ml) measured by bioimpedance
Time frame: Comparison between 2 hour infusion visit 1-2 (Part A) / 1 hour infusion visit 1-4 (Part B), over a maximum period of 15 weeks
Changes in haemodynamic parameters following intravenous infusion of 0.9% saline, glucagon, exenatide and their combination.
Cardiac output (L/min) measured by bioimpedance
Time frame: Comparison between 2 hour infusion visit 1-2 (Part A) / 1 hour infusion visit 1-4 (Part B), over a maximum period of 15 weeks
Changes in haemodynamic parameters following intravenous infusion of 0.9% saline, glucagon, exenatide and their combination.
peripheral vascular resistance (dynes/sec/cm)
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Intravenous infusion of Exenatide (loading 50ng/min for 30 minutes followed by 25ng/min for 30 minutes
Time frame: Comparison between 2 hour infusion visit 1-2 (Part A) / 1 hour infusion visit 1-4 (Part B), over a maximum period of 15 weeks
Changes in haemodynamic parameters following intravenous infusion of 0.9% saline, glucagon, exenatide and their combination.
Heart rate variability (normalised low frequency, LF, high frequency, HF and LF/HF ratio)
Time frame: Comparison between 2 hour infusion visit 1-2 (Part A) / 1 hour infusion visit 1-4 (Part B), over a maximum period of 15 weeks
Changes in glucose homeostasis following intravenous infusion of 0.9% saline, glucagon, exenatide and their combination.
Glucose, in mmol/L
Time frame: Comparison between 2 hour infusion visit 1-5 (Part A) / 1 hour infusion visit 1-4 (Part B), over a maximum period of 15 weeks
Changes in glucose homeostasis following intravenous infusion of 0.9% saline, glucagon, exenatide and their combination.
C-peptide, in pmol/L
Time frame: Comparison between 2 hour infusion visit 1-2 (Part A) / 1 hour infusion visit 1-4 (Part B), over a maximum period of 15 weeks
Changes in glucose homeostasis following intravenous infusion of 0.9% saline, glucagon, exenatide and their combination.
Glucagon, in pg/ml
Time frame: Comparison between 2 hour infusion visit 1-2 (Part A) / 1 hour infusion visit 1-4 (Part B), over a maximum period of 15 weeks
Changes in glucose homeostasis following intravenous infusion of 0.9% saline, glucagon, exenatide and their combination.
Insulin, in pmol/L
Time frame: Comparison between 2 hour infusion visit 1-2 (Part A) / 1 hour infusion visit 1-4 (Part B), over a maximum period of 15 weeks
Changes in glucose homeostasis following intravenous infusion of 0.9% saline, glucagon, exenatide and their combination.
Free fatty acids, in μmol/L
Time frame: Comparison between 2 hour infusion visit 1-2 (Part A) / 1 hour infusion visit 1-4 (Part B), over a maximum period of 15 weeks
Changes in glucose homeostasis following intravenous infusion of 0.9% saline, glucagon, exenatide and their combination.
Total GLP-1 and total active GLP-1, in pg/ml
Time frame: Comparison between 2 hour infusion visit 1-2 (Part A) / 1 hour infusion visit 1-4 (Part B), over a maximum period of 15 weeks
Changes in glucose homeostasis following intravenous infusion of 0.9% saline, glucagon, exenatide and their combination.
Gastric inhibitory polypeptide, in pg/ml
Time frame: Comparison between 2 hour infusion visit 1-2 (Part A) / 1 hour infusion visit 1-4 (Part B), over a maximum period of 15 weeks