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| Name | Class |
|---|---|
| NHS Lothian | OTHER_GOV |
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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.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Nitric Oxide Clamp | Experimental | Forearm blood flow response to Urocortins 2, 3 and Substance P in the presence of Nitric Oxide clamp |
|
| Saline Placebo | Placebo Comparator | Forearm blood flow response to Urocortin 2, Urocortin 3 and Substance P in the presence of saline placebo. |
|
| Fluconazole | Experimental | Forearm blood flow response to Urocortin 2, Urocortin 3 and Substance P in the presence of intra-arterial Fluconazole. |
|
| Aspirin | Experimental | Forearm blood flow response to Urocortin 2, Urocortin 3 and Substance P in the presence of cyclooxygenase inhibition with Aspirin. |
|
| Combined | Experimental | Forearm blood flow response to Urocortin 2, Urocortin 3 and Substance P in the presence of inhibition of cycloxygenase, EDHF and NO pathways with Aspirin, Fluconazole and NO clamp. |
|
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| NO clamp | Drug | 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. |
| Measure | Description | Time Frame |
|---|---|---|
| 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 |
| Measure | Description | Time Frame |
|---|---|---|
| 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 |
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Inclusion Criteria:
Exclusion Criteria:
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| Name | Affiliation | Role |
|---|---|---|
| David E Newby, PhD FRCP | University of Edinburgh | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Wellcome Trust Clinical Research Facility, Royal Infirmary of Edinburgh | Edinburgh | Mid Lothian | EH16 4SA | United Kingdom |
| PubMed Identifier | Type | Citation | Retractions |
|---|---|---|---|
| 23525432 | Derived | Venkatasubramanian S, Griffiths ME, McLean SG, Miller MR, Luo R, Lang NN, Newby DE. Vascular effects of urocortins 2 and 3 in healthy volunteers. J Am Heart Assoc. 2013 Jan 31;2(1):e004267. doi: 10.1161/JAHA.112.004267. |
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| ID | Term |
|---|---|
| D014652 | Vascular Diseases |
| D006331 | Heart Diseases |
| D006333 | Heart Failure |
| ID | Term |
|---|---|
| D002318 | Cardiovascular Diseases |
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| ID | Term |
|---|---|
| D013373 | Substance P |
| D012965 | Sodium Chloride |
| D015725 | Fluconazole |
| D001241 | Aspirin |
| ID | Term |
|---|---|
| D015320 | Tachykinins |
| D007705 | Kinins |
| D036341 | Intercellular Signaling Peptides and Proteins |
| D010455 | Peptides |
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|
|
| Saline | Drug | 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 | Drug | 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 | Drug | 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 | Drug | 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. |
|
| D000602 |
| Amino Acids, Peptides, and Proteins |
| D009479 | Neuropeptides |
| D009842 | Oligopeptides |
| D011506 | Proteins |
| D009419 | Nerve Tissue Proteins |
| D012898 | Autacoids |
| D018836 | Inflammation Mediators |
| D001685 | Biological Factors |
| D002712 | Chlorides |
| D006851 | Hydrochloric Acid |
| D017606 | Chlorine Compounds |
| D007287 | Inorganic Chemicals |
| D017670 | Sodium Compounds |
| D014230 | Triazoles |
| D001393 | Azoles |
| D006573 | Heterocyclic Compounds, 1-Ring |
| D006571 | Heterocyclic Compounds |
| D012459 | Salicylates |
| D062385 | Hydroxybenzoates |
| D010636 | Phenols |
| D001555 | Benzene Derivatives |
| D006841 | Hydrocarbons, Aromatic |
| D006844 | Hydrocarbons, Cyclic |
| D006838 | Hydrocarbons |
| D009930 | Organic Chemicals |