Neuroprotection by Methylene Blue in Cerebral Global Ischemic Injury Induced Blood-Brain Barrier Disruption and Brain Pathology: A Review

Transient global ischemic cerebral injury is a consequence of cardiac arrest and accounts for approximately 450,000 annual deaths with a mortality of approximately 90%. Serious morbidity follows for many of the survivors and up to 16% of patients achieving restoration of spontaneous circulation develop brain death. Other survivors are left with persistent cognitive impairment such as memory and sensimotor deficits, reducing quality of life and resulting in heavy costs on society. Many studies over the years have been devoted to improving outcome after cardiac arrest and have, to a certain degree succeeded, especially locally in areas where improvement of ambulance organizations have been effective. In spite of this serious problems remain and the chances of cerebral survival need to increase if over-all results, i.e. survival as well as cognitive function, are to improve. Methylene blue, a textile dye synthesized in the late 19th century has also been used in medicine for different purposes. One of its effects is to increase systemic blood pressure, but other effects have been documented, among which are its neuroprotective effects well-noted during the last few years. In this review we have appraised these findings in relation to global ischemic injury.