Search results
Results From The WOW.Com Content Network
The main reason for the acute phase of ischemia-reperfusion injury is oxygen deprivation and, therefore, arrest of generation of ATP (cellular energy currency) by mitochondria oxidative phosphorylation. Tissue damage due to the general energy deficit during ischemia is followed by reperfusion (increase of oxygen level) when the injury is enhanced.
The brain sustains irreversible injury after about 20 minutes of ischemia. [4] Even after blood flow is restored to the brain, patients can experience hours-days of hypotension, hypoxemia, impaired cerebrovascular autoregulation , brain edema, fever, hyperglycemia and/or seizures which further insult brain tissue. [ 5 ]
Cerebral hyperperfusion syndrome, also known as reperfusion syndrome, is a dysregulated state of cerebral blood flow following the restoration of arterial blood flow to the brain, usually following treatment of carotid artery stenosis. [1]
Brain ischemia has been linked to a variety of diseases or abnormalities. Individuals with sickle cell anemia, compressed blood vessels, ventricular tachycardia, plaque buildup in the arteries, blood clots, extremely low blood pressure as a result of heart attack, and congenital heart defects have a higher predisposition to brain ischemia in comparison to the average population.
Brain ischemia is insufficient blood flow to the brain, and can be acute or chronic. Acute ischemic stroke is a neurological emergency typically caused by a blood clot blocking blood flow in a vessel in the brain. [15] Chronic ischemia of the brain may result in a form of dementia called vascular dementia. [16]
The caspase-dependent apoptosis cascade is initiated, causing cells to "commit suicide." If the cell dies through necrosis, it releases glutamate and toxic chemicals into the environment around it. Toxins poison nearby neurons, and glutamate can overexcite them. If and when the brain is reperfused, a number of factors lead to reperfusion injury.
Cerebral hypoxia is hypoxia specifically involving the brain. The four categories of cerebral hypoxia in order of increasing severity are: diffuse cerebral hypoxia (DCH), focal cerebral ischemia, cerebral infarction, and global cerebral ischemia. Prolonged hypoxia induces neuronal cell death via apoptosis, resulting in a hypoxic brain injury ...
In the end the apoptosis pathway is initiated and cell death occurs. [39] There are several arteries that supply oxygen to different areas of the brain, and damage or occlusion of any of them can result in stroke. [40] The carotid arteries cover the majority of the cerebrum. The common carotid artery divides into the internal and the external ...