Effects of Urocortins on Forearm Arterial Blood Flow in Healthy Volunteers (Protocol 3)

Heart Disease Clinical Trial

Official title:

Effects of Urocortins on Forearm Arterial Blood Flow in Healthy Volunteers

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT01096706
• Other study ID #: SV.Protocol 3
• Status: Completed
• Phase: N/A
• First received: March 30, 2010
• Last updated: May 14, 2012
• Start date: July 2011
• Est. completion date: January 2012

Study information

• Verified date: May 2012
• Source: University of Edinburgh
• Contact: n/a
• Is FDA regulated: No
• Health authority: United Kingdom: Research Ethics Committee
• Study type: Interventional

Clinical Trial Summary

Impairment of the heart's pumping capacity (heart failure) remains a major clinical problem with a poor prognosis and the search for novel treatments remains an important area of research.

Urocortins are proteins that appear to increase blood flow and heart pumping activity. There has been particular interest in the role of Urocortins 2 & 3 (subtypes of Urocortins) in heart failure.

In this study, we will examine the effects and mechanisms of Urocortins 2 & 3 on forearm blood flow and release of natural blood clot dissolving factors in the forearm circulation of healthy volunteers. In particular, we look at the endothelial mechanisms of vasodilatation of Urocortin 2 and 3.

In this study, we will look at the role of the lining of the blood vessel (endothelium) in response to urocortin types 2 and 3. We hypothesise that urocortins 2 & 3 act via the endothelium to cause dilatation of the blood vessels and release of tissue-plasminogen activating factor (blood clot dissolving factor). We also hypothesise that urocortins have a role in maintaining the normal baseline level of blood flow in forearm arteries. In addition to the above, we will also look at the effect of temporarily blocking the effect of urocortins, using a specially designed blocker drug (Astressin 2B).

Utilising the well-established technique of 'forearm venous occlusion plethysmography', we will be able to focus on the local effects of urocortins on arterial blood flow in forearm vessels, without affecting this system in the body as a whole.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 10
• Est. completion date: January 2012
• Est. primary completion date: January 2012
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: Male
• Age group: 18 Years to 65 Years

Eligibility

Inclusion Criteria:

• Healthy male volunteers between 18 - 65 years (inclusive)

Exclusion Criteria:

• Lack of informed consent- Age <18 years > 65 years

• Current involvement in a clinical trial

• Severe or significant co-morbidity including bleeding diathesis, renal or hepatic failure

• Smoker

• History of anaemia

• Recent infective/inflammatory condition

• Recent blood donation (prior 3 months)

• Positive baseline urine test for drugs of abuse (including cannabinoids, benzodiazepines, opiates, cocaine and amphetamines)

• History of allergy to Aspirin

Study Design

Allocation: Randomized, Endpoint Classification: Pharmacodynamics Study, Intervention Model: Crossover Assignment, Masking: Double Blind (Subject, Investigator), Primary Purpose: Basic Science

Related Conditions & MeSH terms

• Heart Disease
• Vascular Disease
• Vascular Diseases

Intervention

Drug:
• NO clamp
After a 20 minute saline washout period, ascending doses of Urocortin 2, Urocortin 3 and substance P (doses as per Protocol 2) will be infused intra-arterially in the presence or the absence of the 'nitric oxide clamp' that will be commenced prior to the infusion of Urocortin 2, Urocortin 3 and substance P, and will be continued throughout the study. Baseline blood samples will be taken from both forearms at the start of the study for full blood count, cholesterol, glucose, renal function and t-PA and PAI-1 activity and antigen concentrations. Bilateral venous blood samples will be taken at baseline, immediately before the start of Ucn2/Ucn3 infusion and at the end of each dose of Ucn2/Ucn3 for subsequent calculation of net release of t-PA and PAI-1.
• Saline
After a 20 minute saline washout, incremental doses of Urocortin 2, Urocortin 3 and Substance P (in doses as per Protocol 2) will be infused in the presence of saline placebo. Baseline blood samples will be taken from both forearms at the start of the study for full blood count, cholesterol, glucose, renal function and t-PA and PAI-1 activity and antigen concentrations. Bilateral venous blood samples will be taken at baseline, immediately before the start of Ucn2/Ucn3 infusion and at the end of each dose of Ucn2/Ucn3 for subsequent calculation of net release of t-PA and PAI-1.
• Fluconazole
After a 20 minute saline washout period, ascending doses of Urocortin 2, Urocortin 3 and substance P (doses as per Protocol 2) will be infused intra-arterially in the presence of Fluconazole (which serves to inhibit the EDHF pathway) that will be commenced prior to the infusion of Urocortin 2, Urocortin 3 and substance P, and will be continued throughout the study. Baseline blood samples will be taken from both forearms at the start of the study for full blood count, cholesterol, glucose, renal function, plasma Ucn 2 and 3 and t-PA and PAI-1 activity and antigen concentrations. Bilateral venous blood samples will be taken at after the top dose of Ucn2/Ucn3 infusion and before and after each dose of Substance P for subsequent calculation of plasma Ucn 2/ Ucn 3 and net release of t-PA and PAI-1.
• Aspirin
Oral Aspirin (600mg stat) will be administered 30 minutes before start of the study. After a 20 minute saline washout period, ascending doses of Urocortin 2, Urocortin 3 and substance P (doses as per Protocol 2) will be infused intra-arterially in the presence of saline. Baseline blood samples will be taken from both forearms at the start of the study for full blood count, cholesterol, glucose, renal function, plasma Ucn 2 and 3 and t-PA and PAI-1 activity and antigen concentrations. Bilateral venous blood samples will be taken at after the top dose of Ucn2/Ucn3 infusion and before and after each dose of Substance P for subsequent calculation of plasma Ucn 2/ Ucn 3 and net release of t-PA and PAI-1.
• Combined
Oral Aspirin (600mg stat) is administered 30 minutes before start of the study. After a 20 minute saline washout period, ascending doses of Urocortin 2, Urocortin 3 and substance P (doses as per Protocol 2) will be infused intra-arterially in the presence of the 'nitric oxide clamp' that will be commenced prior to the infusion of Urocortin 2, Urocortin 3 and substance P, and will be continued throughout the study. Intra-arterial Fluconazole is also commenced at the time of the Nitric oxide clamp. This serves to inhibit the cyclooxygenase, EDHF and NO pathways of endothelial vasodilatation. Blood samples are taken as per previous arms.

Locations

Country	Name	City	State
United Kingdom	Wellcome Trust Clinical Research Facility, Royal Infirmary of Edinburgh	Edinburgh	Mid Lothian

Sponsors (2)

Lead Sponsor	Collaborator
University of Edinburgh	NHS Lothian

Country where clinical trial is conducted

United Kingdom, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Forearm blood flow	The difference between forearm blood flow in response to incremental doses of Ucn2, Ucn3 and Sub P in the presence vs absence of 'the nitric oxide clamp'	3 hours	No
Secondary	Net t-PA release	Net release of t-PA evoked by Ucn 2, Ucn 3 and Substance P, in the presence vs absence of a 'nitric oxide clamp'.	3 hours	No