Gap Junction Potentiation of Endothelial Function With Rotigaptide

Summary

Hypothesis - Rotigaptide will improve endothelial function in the context of endothelial dysfunction.

The lining of blood vessels (endothelium) can react to hormones in the blood stream causing the blood vessel muscle to relax (vasodilatation) and allow more blood to flow. The nitric oxide and prostacyclin pathways are well documented in this process. However, evidence points to the existence of a third powerful relaxant called endothelium derived hyperpolarising factor (EDHF) but its identity and mechanism of action have proved elusive. As well as causing blood vessels to relax and more blood to flow, EDHF may be involved in the endothelium signaling, triggering release of a specialised clot dissolving factor called tissue plasminogen activator (t PA). t PA is important to ensure small clots, which are constantly being formed in the circulation, are rapidly dissolved and do not grow large enough to cause heart attacks and strokes.

Evidence points towards the requirement for 'gap junctions' in the mediation of EDHF responses. Gap junctions are specialised pores which allow small molecules and charge to pass between cells. They are found between endothelial cells and the underlying muscle of the blood vessel. A drug called Rotigaptide has been developed to cause gap junctions to open. It has been safely administered in healthy volunteers and is now in a Phase II drug trial. By opening gap junctions the investigators hypothesise that it could increase EDHF mediated activity and vasodilatation. It represents a useful tool with which to examine the role of gap junctions in EDHF activity in vivo.

Previously the investigators have demonstrated that rotigaptide does not contribute to endothelial function in healthy volunteers. The investigators now wish to examine the effect of rotigaptide in conditions of endothelial dysfunction. By limiting the blood flow to the arm for 20mins the ability of the blood vessel to vasodilate is impaired. By administering an intra-arterial rotigaptide infusion the investigators want to assess any functional preservation.

Conditions

• Vascular Disease
• Heart Disease

Interventions

DRUG

Rotigaptide

Prior to 20 mins of ischaemia induced by a blood pressure cuff inflated to 200 mmHg around the upper non-dominant arm, rotigaptide will be infused for 30mins. During the ischaemic period no drug will be infused but the infusion will be restarted once the blood pressure cuff has been deflated and blood flow returns to the limb.

OTHER

Forearm vascular study

Forearm blood flow measured by venous occlusion plethysmography during interarterial infusion of substance P (2,4,8 pmol/min) or Acetylcholine (5, 10 , 20 micromol/min) . Venous blood sampling via cannula in antecubital fossa.

Sponsors & Collaborators

• Chief Scientist Office of the Scottish Government

  collaborator OTHER_GOV

• NHS Lothian

  collaborator OTHER_GOV

• University of Edinburgh

  lead OTHER

Principal Investigators

• David E Newby, MD · University of Edinburgh

Study Design

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

DOUBLE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Max Age

64 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2009-03-31

Primary Completion

2015-08-03

Completion

2015-08-03

Countries

• United Kingdom

Study Locations