Stroke is a severe disease which is characterised by sudden onset and frequently followed by prolonged disabilities or the death of the patients. With 1.8 million new stroke patients every year (in the industrialized world), and 200,000 new patients in Germany alone, stroke is ranked number three as cause of death in these nations (in the US it is already number two), and it is one of the major causes for disabilities in these countries.
The most common form of stroke is brain ischemia (approximately 80-85%, with 20% lethality). It is caused when the blood supply of the brain is disrupted by a thromboembolic event/clot. As a result, supply of oxygen and nutrients to the affected brain area are diminished. Following the reduced blood supply, massive neuronal cell death occurs and inflammatory and edematous processes are activated, which further increase the lesion and the infarct area, leading to neurological deficits as overall consequence.
Currently, only one pharmacological therapy is approved for the treatment of acute ischemic stroke in the US and in Europe: lysis of the blood clot obstructing the vessel by tissue plasminogen activator (t-PA). A drawback of the currently approved lysis therapy is that it is only recommended for treatment within 4,5 hours after the onset of symptoms and requires extensive diagnostic proceedings necessary to diagnose stroke and to exclude other reasons of disease. Currently only a limited number of stroke patients receive lysis therapy.