Adenosine Receptors Influence Ischemia-Reperfusion Injury

Not Applicable

Suspended

• Conditions: Ischemia-Reperfusion Injury

• Registration Number: NCT00184847
• Lead Sponsor: Radboud University Medical Center

Brief Summary

Ischemic preconditioning is defined as the development of tolerance to ischemia-reperfusion injury by a previous short bout of ischemia resulting in a marked reduction in infarct size. This mechanism can be mimicked by several pharmacological substances such as acetylcholine and adenosine.

To detect ischemia-reperfusion injury in humans in vivo Kharbanda et al. developed a method in which endothelial dysfunction represents the effects of ischemic preconditioning. This method, however, uses acetylcholine to measure endothelial function before and after forearm ischemia. We, the investigators at Radboud University, hypothesize that the use of acetylcholine in this model reduces ischemia-reperfusion injury. Therefore, we will compare this protocol with a protocol in which endothelial function is only measured after ischemia. We expect an increase in ischemia-reperfusion injury when endothelial function is only measured after the forearm ischemia.

After determining the optimal method to measure ischemia-reperfusion injury of the vascular endothelium we will determine the effect of acute and chronic caffeine, an adenosine receptor antagonist, on ischemic preconditioning. With this study we expect to find that adenosine mimics ischemic preconditioning of the vascular endothelium. Moreover, we expect to find that acute caffeine intake reduces ischemia-reperfusion injury whereas chronic caffeine intake does not. This study will increase our knowledge about the mechanism of ischemic preconditioning and may also provide leads to exploit this endogenous protective mechanism in a clinical setting.

Detailed Description

Not available

Study Timeline

• Study Start: 2005-03
• Study First Submitted: 2005-09-12
• Study First Submitted QC: 2005-09-12
• Study First Posted: 2005-09-16
• Status Verified: 2008-03
• Last Update Submitted: 2008-03-27
• Last Update Posted: 2008-03-28

Recruitment & Eligibility

• Status: SUSPENDED
• Sex: All
• Target Recruitment: 8

Inclusion Criteria

• Healthy volunteers

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Exclusion Criteria

Not provided

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Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Primary Outcome Measures

Name	Time	Method
Percentual increase in forearm blood flow ratio to three increment dosages of acetylcholine before forearm ischemia and within two hours after forearm ischemia

Trial Locations

Locations (1)

Radboud University Nijmegen Medical Centre/Department of Pharmacology and Toxicology; 🇳🇱 Nijmegen, Gelderland, Netherlands