After a stroke, even unaffected areas of the brain are at risk depolarization waves arise at the edges of the dead tissue and spread through the adjacent areas of the brain. If these waves are repeated, more cells die. This has previously been observed only in animal studies.
A clinical study at the university hospitals of Cologne and Heidelberg along with the Max Planck Institute of Neurological Research in Cologne has shown for the first time that this phenomenon occurs after a stroke in humans and is a warning sign that more nerve cells will die. The study, published in June 2008 in the renowned journal Annals of Neurology, may allow to translate more than 60 years of experimental research for the diagnosis and therapy of stroke patients.
More than 150,000 people a year in Germany suffer a cerebral stoke, the third most frequent cause of death in industrialized countries. When deposits clog vessels to the brain, some areas of the brain do not receive sufficient oxygen and the tissue dies. Depending on the size of the area affected, the patients may die or suffer permanent damage such as paralysis.
Spreading depolarizations first proven in stroke patients
The depolarization waves in the brain known as cortical spreading depression (CSD) have been studied only experimentally since the 1940s. Many features are thus known from animals the waves of depolarization that can spread out at a speed of two to five millimeters per minute are followed by silence brain activity comes to a halt for a short time. In this time, the nerve cells recover. "The impact of these waves is several times greater for nerve cells than an epileptic seizure," says Professor Dr. Rudolf Graf from the Max Planck Institute of Neurological Research and co-founder of the international study group COSBID (Cooperative Study on Brain Injury Depolarisations).
"After the stroke, circulation in the tissue surrounding the affected are
|Contact: Dr. Annette Tuffs|
University Hospital Heidelberg