View clinical trials related to Reperfusion Injury.
Filter by:Major liver surgery often requires the surgeon to temporarily halt the afferent blood flow in order to prevent excessive blood loss. However, this predisposes the liver to a detrimental inflammatory response once the circulation is restored. Altogether, the effects that result from this temporary withdrawal of blood are known as ischemia and reperfusion (I/R) injury, and the extent to which this occurs determines the functional outcome of the liver after surgery. Recently, it has become clear that (over)activation of the immune system forms the mainstay of I/R injury in the liver. More importantly, it has been shown in animal models that self-antigens, which are normal cellular constituents that become immunogenic mediators following their release from dying cells, are involved in the earliest stages of I/R injury of the liver. Clinical data on the release self-antigens in I/R injury are however scarce to date. Therefore, the aim of this study is to investigate the release of self-antigens in patients that undergo a major liver resection with or without withdrawal of the liver's blood flow. Also, the results will be correlated to genes involved in the inflammatory response as well as clinical parameters for liver damage and function.
Surgical correction of congenital heart defects in children requires the utilization of cardiopulmonary bypass, a technique that temporarily substitutes heart and lung functions during surgery. During this process the patient´s circulation is controlled by a bypass machine which provides several functions: 1. Controls the patient's blood flow by pumping of blood in the patient's body. 2. Controls the correct oxygen levels in the patient's blood. 3. Regulates the temperature and fluid level of the blood. This process triggers negative responses in the heart and throughout the whole body, potentially resulting in injury to the heart and other organs such as brain, kidneys and lungs. Remote ischaemic preconditioning (RIPC) describes a procedure that could potentially reduce the injury to heart muscle during cardiac surgery. The procedure consists of the inflation of a blood pressure cuff on the child's leg for three 5 minute cycles. This process acts by briefly reducing blood flow to the leg muscle, which will then activate the body´s own protective mechanisms and thereby reduce heart injury. Several animal studies have been used to help the understanding of the mechanisms behind this process, and trials in human adults have showed optimistic results; however evidence regarding the paediatric population is limited and necessary since children present different basal profiles, risks and requirements. The investigators propose a randomized clinical trial assessing the efficacy of RIPC to provide protection against injury to the heart and other organs in children going through cardiac surgery using CPB at the Royal Hospital for Sick Children. The research project will have a translational approach, integrating basic molecular mechanisms to clinical outcome. The investigators hope it will allow the understanding and utilisation of the patient´s own protective mechanisms, reducing CPB-related injury and ultimately improving patient outcome.
The purposes of this study are two-fold. The first purpose is to determine the effect of taking vitamins on the recovery of an artery (blood vessel) following an induced temporary injury. The second purpose is to determine whether a specific vasodilator is less abundant after the injury and whether this contributes to increased constriction or after the injury. Finally, does vitamin consumption have an effect on the recovery from the injury if one of the substances in the blood that causes vessels to enlarge (dilate) is stopped?
Tea consumption may impact upon the decrease in endothelial function after IR-injury. However, no previous study directly examined the potential of tea to impact upon the change in endothelial function after IR-injury. The investigators hypothesize that tea consumption counteracts endothelial damage in response to ischaemia reperfusion injury in healthy humans.
The release of tourniquet produces reactive oxygen species which can cause injury. Propofol is chemically similar to phenol-based free radical scavengers. Plasma total antioxidant capacity is a well-established marker of the overall protective effect of antioxidants in body fluids.The aim of the study is to investigate the effects of propofol on ischemia-reperfusion injury in total knee arthroplasty (TKA).
The investigators are trying to evaluate the clinical effect of remote ischemic postconditioning on liver graft function and postoperative renal function in subjects undergoing living-donor liver transplantation.
In acute myocardial infarction early restoration of coronary blood flow is the most effective strategy to limit infarct-size. Paradoxically, reperfusion itself also aggravates myocardial injury and contributes to final infarct size, a process termed 'reperfusion injury'. Ischemia and reperfusion (IR)-induced endothelial dysfunction seems to play a pivotal role in this process, resulting in vasoconstriction and reduced blood flow to the already ischemic tissue. Recently, it has been shown that the glucose-lowering drug metformin is able to limit IR-injury in murine models of myocardial infarction, probably by increased formation of the endogenous nucleoside adenosine. In the current research proposal, the investigators aim to translate this finding to the human in vivo situation, using flow-mediated dilation (FMD) of the brachial artery as a well-validated model of (endothelial) IR-injury.
Rationale: Ischaemic preconditioning (IP) refers to the reduction of ischemia-reperfusion injury induced by a brief preceding period of ischemia. Also the arterial endothelium can be protected by IP. Several studies performed in animals and humans have demonstrated that the protective effects of IP are attenuated with aging. However, no previous study directly examined the underlying mechanisms of this observation. Possibly, the reduced protective effect of IP with aging relates to a direct effect on the endothelium, consequently leading to an attenuated ability of IP to prevent endothelial dysfunction after ischaemia reperfusion injury. Several previous studies failed to demonstrate the ability of pharmacological stimuli to mimic the beneficial effects of IP in aged vessels. Restoration of the age-related reduction in effectiveness of IP may be possible through exercise training. In aged animals, physical training restores the efficacy of ischemic preconditioning. Indirect evidence indicates that physical activity, independent of other cardiovascular risk factors, protects against a occurrence as well as the severity of a myocardial infarction in humans. Although this suggests that physical activity may beneficially influence the age-related reduction in IP, no previous study provided direct evidence for this hypothesis. Objective: To examine the impact of age and physical fitness on the ability of ischaemic preconditioning to protect endothelial damage in response to ischaemia reperfusion injury in healthy humans. A secondary objective is to explore the role of Toll-like receptor (TLR) signalling in the induction of IP in young and old subjects.
The use of volatile anesthetics in cardiac anesthesia is very common, because of their cardioprotective effects and their ability to ensure a sufficient depth of anesthesia. In line with the development of fast track concepts in cardiac anesthesia, volatile anesthetics are widely used to avoid a delayed recovery from cardiac surgery and anesthesia. Volatile anesthetics are delivered from calibrated vaporizers in the anesthesia machine or the cardiopulmonary bypass machine (during extracorporeal circulation). Isoflurane and Sevoflurane are the most commonly used volatile anesthetics in patients undergoing cardiopulmonary bypass (CPB). The vaporizer of the anesthetics is on the cardiopulmonary bypass machine and the volatile agent is blended with air and oxygen. Until now, the pharmacokinetics of halothane, enflurane, isoflurane and desflurane during CPB have been described. Sevoflurane might be of advantage because of additional myocardial protective effects during cardiac anesthesia and cardiopulmonary bypass. However, the pharmacokinetics of sevoflurane during CPB have not been investigated so far, although its being used at many hospitals. The investigators will conduct a randomized prospective study with either sevoflurane or isoflurane during cardiopulmonary bypass surgery. The study will help to answer the questions about the possible cardioprotective effects of the widely used volatile anesthetics and the hemodynamic stability during cardiopulmonary bypass. Knowing the pharmacokinetics of these drugs allows the anesthesiologist to titrate the volatile anesthetics more precise. The investigators hypothesizes that the maximal postoperative increase in troponin T will be smaller in the sevoflurane group than in the isoflurane group. The investigators hypothesizes that the total amount of noradrenaline needed during the entire period of cardiopulmonary bypass will be smaller in the sevoflurane group than in the isoflurane group. The investigators hypothesizes that kinetics of washin and washout at the CPB will be faster in the sevoflurane group than in the isoflurane group. The investigators hypothesizes that the time to extubation, respectively the length of stay in intensive care unit and hospital is shorter in the sevoflurane group than in the isoflurane group.
Despite advances in the treatment of heart attacks the complications and death rates from failure of the heart to pump properly after treatment remain high. A heart attack occurs when one or more of the arteries that supply blood to the heart become blocked, causing the heart to be starved of oxygen and nutrients. This results in damage to the heart and so the the heart pumps less well. The main treatment for a heart attack is balloon treatment to open the blocked artery (called primary angioplasty). Whilst re-opening the artery is essential and allows blood to flow to the area of the heart starved of oxygen, this process also causes damage itself (called reperfusion injury) and increases the size of the heart attack further. Currently there are no treatments available that reduce this reperfusion injury. The investigators and others have shown that a substance called sodium nitrite reduces reperfusion injury in experimental models of a heart attack. The aim of this research is to perform a trial to investigate whether during a heart attack, an infusion of sodium nitrite into the damaged artery protects against reperfusion injury and reduces heart attack size in patients.