View clinical trials related to Reperfusion Injury.
Filter by: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.
The EMBRACE-STEMI trial was a Phase 2a prospective, multicenter, multinational randomized, double-blind, placebo-controlled study designed to assess the safety, tolerability, and efficacy of IV administered elamipretide (also known as MTP-131, or Bendavia) on a background of standard-of-care therapy for reduction of reperfusion injury in patients with first time acute, anterior wall ST-segment elevation myocardial infarction (STEMI).
Rationale Currently, hepatic resection is often the only curative treatment for primary or secondary hepatic malignancies and is also frequently performed in patients with benign liver tumors to prevent malignant transformation and/or alleviate symptoms. Liver resections are nowadays associated with low mortality and acceptable morbidity. As result of that, an increasing number of patients is currently under consideration for resection of more complex or large tumors, thus requiring extensive resection procedures. Application of vascular exclusion (i.e., clamping of the portal vein and hepatic artery) during such procedures reduces blood loss, which is one of the most important factors affecting peri-operative outcomes. However, vascular exclusion leads to ischemia-reperfusion (I/R) injury as an inevitable side-effect, which adversely impacts postoperative liver function and regeneration. Additional cooling of the liver by means of hypothermic perfusion is expected to further reduce intraoperative blood loss, as well as to protect the liver from I/R injury. Therefore, the aim of this pilot study is to cool the future remnant liver (FRL) in situ during right hemihepatectomy under vascular exclusion. Consequently, an overall improvement in postoperative outcomes is expected due to a decrease in intraoperative blood loss, reduced parenchymal damage, and a better ability of the liver remnant to regenerate. Objective To reduce intraoperative blood loss and enhance tolerance of the FRL to I/R injury during right hemihepatectomy under vascular exclusion by means of in situ hypothermic perfusion with retrograde outflow (R-IHP) of the FRL. Study design The study is designed as a prospective randomized pilot study in 18 patients (9 interventions and 9 controls) to assess the effects of the proposed intervention. Additionally, 4 patients will be included separately for assessment of the intervention's feasibility prior to randomized inclusion. Study population Eligible patients for participation in this study are those planned to undergo right hemihepatectomy under vascular inflow occlusion because of a malignant or benign liver tumor, and who do not suffer from any hepatic co-morbidity that might influence postoperative outcomes (i.e., severe steatosis, cholestasis, cirrhosis, or hepatitis B/C infection). Intervention During right hemihepatectomy, the FRL of patients allocated to the intervention group will be perfused with a chilled perfusion solution (i.e., lactated Ringer's solution).
Oxygen is necessary for the survival of oxygen consuming organisms. But the organisms metabolism alter the oxygen to free radicals. Free radicals are molecules which due to their structure can react with other molecules resulting in cell damage. This damage is due to several mechanisms. This is e.g what happens when human tissue is cut of from blood supply for a time, and the blood supply is again restored. The damage following the restoration of blood is known as "ischemia-reperfusion injury". The reopening of the vessels and thereby supplying oxygenated blood to the deprived tissue can in it self contribute to cell death due to excessive amounts of free radicals. Antioxidants can neutralize free radicals and thereby minimize their damage. The purpose of the investigators methodology study is to make an ischemia-reperfusion model on healthy volunteers (on the lower limb) to examine the expression of markers that are expressed in the muscle and the blood when blood supply is cut of to an area and later restored. The investigators wish to measure the product of the damage caused by free radicals and the levels of antioxidants. If the investigators can produce elevation of oxidative and inflammatory markers, this model can be used to test antioxidative intervention.
The investigators previously reported that angioplasty postconditioning reduces infarct size (cardiac enzyme release) in STEMI patients with a fully occluded coronary artery at hospital admission. Animal studies have suggested that the time window for applying brief episodes of ischemia and reperfusion aimed at triggering postconditioning's protection is very narrow, i.e. does not expand beyond 1 minute after reflow. We sought to address whether this window might be larger in humans, i.e. whether STEMI patients might be protected several minutes after undergoing spontaneous reperfusion before admission coronary angiography. Therefore, STEMI patients (onset of chest pain less than 12 hours) with a TIMI flow grade > 1 were eligible for that study. Angioplasty postconditioning was completed as already published and infarct size was assessed by measuring cardiac enzymes release.
The overall purpose of this study is to evaluate the safety, pharmacokinetics and preliminary efficacy of a five-days post-operative course of Treprostinil in liver transplant patients. The hypothesis of this study is that Treprostinil can be safely administered post-operatively in liver transplant patients. Once safety is documented future studies will address its ability to ameliorate or prevent reperfusion mediated dysfunction of the liver graft and thereby reduce morbidity, leading to shorter hospital stays as compared to historical controls.