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Reperfusion injury, sometimes called ischemia-reperfusion injury (IRI) or reoxygenation injury, is the tissue damage caused when blood supply returns to tissue (re-+ perfusion) after a period of ischemia or lack of oxygen (anoxia or hypoxia).
Ischemia-reperfusion (IR) tissue injury is the resultant pathology from a combination of factors, including tissue hypoxia, followed by tissue damage associated with re-oxygenation. IR injury contributes to disease and mortality in a variety of pathologies, including myocardial infarction , ischemic stroke , acute kidney injury , trauma ...
Restoration of blood supply to ischemic tissues can cause additional damage known as reperfusion injury that can be more damaging than the initial ischemia. Reintroduction of blood flow brings oxygen back to the tissues, causing a greater production of free radicals and reactive oxygen species that damage cells.
This reperfusion results in inflammatory injury through three overlapping mechanisms. Some complimentary combination of, first, mitochondrial damage and, second, endothelial activation , causes a release of reactive oxygen species (ROS), which initiates and/or exacerbates a pathophysiological inflammatory response.
Reperfusion therapy is a medical treatment to restore blood flow, either through or around, blocked arteries, typically after a heart attack (myocardial infarction (MI)). Reperfusion therapy includes drugs and surgery. The drugs are thrombolytics and fibrinolytics used in a process called thrombolysis.
Contraction band necrosis is a type of uncontrolled cell death unique to cardiac myocytes and thought to arise in reperfusion from hypercontraction, which results in sarcolemmal rupture. [1] It is a characteristic histologic finding of a recent myocardial infarction (heart attack) that was partially reperfused.
However, if a significant amount of time passes before restoration, brain damage may be permanent. While reperfusion may be essential to protecting as much brain tissue as possible, it may also lead to reperfusion injury. Reperfusion injury is classified as the damage that ensues after restoration of blood supply to ischemic tissue. [16]
Neutrophil granulocytes—the most abundant type of white blood cell—enter the muscle tissue, producing an inflammatory reaction and releasing reactive oxygen species, [11] particularly after crush injury. [10] Crush syndrome may also cause reperfusion injury when blood flow to decompressed muscle is suddenly restored. [10]