View clinical trials related to Ischemia Reperfusion Injury.
Filter by:The most powerful protective mechanism against ischemia-reperfusion injury other than rapid reperfusion is ischemic preconditioning. 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 adenosine and morphine. We, the researchers at Radboud University Nijmegen Medical Centre, have recently developed a method in which we can detect ischemia-reperfusion injury in the human forearm by using Annexin A5 scintigraphy (Rongen et al). With this method we will determine whether opioid receptors are involved in ischemic preconditioning. We expect to find that morphine can mimic ischemic preconditioning and that acute ischemic preconditioning can be blocked with the opioid receptor antagonist naloxon. 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.
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.