The goal of this trial is to study the effect that adrenaline has on the immune reaction seen during a low blood sugar. People with type 1 diabetes do not produce their own insulin. The cells in the pancreas that produce insulin are destroyed. People with type 1 diabetes require daily insulin administration. As a consequence of this insulin therapy the blood sugar can dip too low, causing symptoms such as confusion, irritation and tiredness. This is called hypoglycaemia. Hypoglycaemia has been associated with an increased risk for cardiovascular disease such as heart attacks. During hypoglycaemia the immune system is activated. The immune system consists of white blood cells which produce cytokines, these are proteins used to kill pathogens such as bacteria. During hypoglycaemia there are no pathogens but the cytokines are still produced, leading to unwanted damage. A previous study performed by our research group showed that the immune system activation caused by hypoglycaemia is associated with the stress hormone adrenaline. Adrenaline is released by the body in moments of stress such as during running or bungee jumping. Adrenaline is also released by the body during hypoglycaemia to increase the sugar level. Our hypothesis is that adrenaline activates the immune system during hypoglycaemia. Adrenaline acts in the body through two receivers, these are called alpha and beta receptors. These are present on almost all cells in the body especially on the immune cells. With the study we want to study the situation where there is a hypoglycaemia without the adrenaline. We will achieve this by lowering the blood sugar in participants. During the low blood sugar we will administer two drugs, which will attach themselves to the adrenaline receivers, the alpha and beta receptor. With this method we hope to block the adrenaline effects and with that block the immune response caused by adrenaline.

Rationale: Hypoglycaemia has shown to cause a sustained pro-inflammatory response which could promote a pro-atherogenic state and explain the association between hypoglycaemia and cardiovascular events. This pro-inflammatory response has been linked to the adrenaline response to hypoglycaemia. Adrenergic blockade with α and β adrenergic receptor antagonists (ARA) has shown to blunt the leukocyte response after hypoglycaemia induction and adrenaline administration. Whether and to what degree a combined blockade blunts the hypoglycaemia induced pro-inflammatory response is unknown.

Objective: to examine the effect of adrenergic inhibition on the hypoglycaemia induced inflammatory response (e.g. leukocyte phenotype, cytokines, inflammatory proteins) by performing a hyperinsulinaemic hypoglycaemic glucose clamp alongside infusion of α-ARA and β-ARA. Secondary objectives consist of the effect of adrenergic blockade during hypoglycaemia on atherogenic parameters and glucose metrics ( e.g. time in range).

Study design: Intervention study with a cross-over design

Study population: Potentially eligible adult ( 16 - 75 years) participants will be recruited through social media, the Radboudumc outpatient clinic and other advertisements. We will recruit a total of 24 individuals, i.e. 12 healthy participants and 12 participants with type 1 diabetes. Participants with type 1 diabetes will be twice ( as there are two investigational days) equipped with a blinded continuous glucose monitoring device (CGM) during the test, which will measure interstitial glucose levels for a total of 10 days.

Intervention: All participants will undergo a hyperinsulinaemic hypoglycaemic glucose clamp ( nadir 2.8 mmol/L). During the clamp the participants will be randomized to receive an infusion of saline or an infusion of phentolamine and propranolol. This will be done using a cross-over design. The participants will undergo both the saline and adrenergic blockade.

Main study parameters/endpoints: The main study parameter will be the monocyte count after 60 minutes hyperinsulinaemic hypoglycaemic clamp and adrenergic blockade during the clamp.

Inclusion Criteria:

• Overall inclusion criteria:

  • Ability to provide written informed consent
  • Body-Mass Index: 18,5-35 kg/m2
  • Age ≥16 years, ≤ 75 years
  • Blood pressure: <140/90 mmHg
  • Non-smoking
  • Electrocardiogram not showing any serious arrythmias (premature ventricular complexes and premature atrial complexes accepted)

Diabetes group specific criteria:

• Insulin treatment according to basal-bolus insulin regimen (injections or insulin pump)
• Duration of diabetes > 1 year
• HbA1c < 100 mmol/mol,

Exclusion Criteria:

• Any event of cardiovascular disease in the past 5 years (e.g. myocardial infarction, stroke, symptomatic peripheral arterial disease)
• Pregnancy or breastfeeding or unwillingness to undertake measures for birth control
• Active epilepsy ( with the need for treatment)
• Allergy for sulphite
• Active asthma with use of β2-bronchodilators or obstructive lung disease
• Current treatment with Alpha- or beta-blockers (e.g. doxazosin, propranolol)
• History of clinical significant Arrhythmias
• Use of immune-modifying drugs or antibiotics
• Use of antidepressants ( Including monoamine oxidase inhibitors, tricyclic antidepressants and serotonin-reuptake inhibitors)
• Use of antipsychotics
• Use of statins with the inability to stop statins >2 weeks before the investigational day.
• Proliferative retinopathy
• Nephropathy with an estimated glomerular filtration rate (by Chronic Kidney Disease Epidemiology Collaboration equation, CKD-EPI) ˂60ml/min/1.73m2

We aim to match our participants with each other to have comparable groups. So we aim to have the same amount of males and females.

We will share the study protocol using a data repository accessible through the research team on demand. Starting around 6 months after publication.

6 months after publication

The coordinating researcher will review access requests. Seeing as the data are all anonymized access will be granted for additional research in the field of inflammation or diabetes.

Participants will be blinded tot the co-infusion during hypoglycaemia. This will be achieved by similar labelling, with phentolamine having the label infusion A and the propranolol infusion having the label infusion B. When administering saline the 50 milliliter syringes will be filled with saline instead of the solution containing either phentolamine or propranolol. Both saline syringes will still have the labels infusion A and infusion B. The investigators will not be blinded as they will be preparing the adrenergic solutions and the saline solutions. The participants will receive the same amount of millilitres during both infusions, determined by the amount infused during adrenergic blockade. Participants will be block-randomized with blocks of 2 using a randomisation list allocated to receive either the adrenergic blockade or the saline first. The coordinating investigator will have access to this list.