Our brain is not able to repair by itself the damage that occurs after a stroke, but scientific evidence shows that there are processes of spontaneous neuronal repair and that rehabilitative treatment is able to reduce the disabling outcomes by activating areas that vicar those damaged. On this subject, which sees diverging results of studies, doctors investigate to clarify the mechanisms in place after acute brain damage and to develop therapies that can limit the highly disabling effects of stroke or head trauma. According to the 2018 data of the Osservatorio Ictus Italia, stroke represents the first cause of disability in the world, the second of dementia and the third of mortality in Western countries. We talked about it with Dr. Simona Marcheselli, head of the autonomous section of emergency neurology and stroke unit of Humanitas.
Stroke, every year 200,000 new cases
Ischemic stroke, with 200,000 new cases a year in our country, is an event with often serious outcomes, as evidenced by the million Italians who suffer from the disabling outcomes of the disease. It is a neurological emergency that must be treated as soon as possible, because the time that elapses from stroke to therapeutic intervention has a decisive role on the prognosis in terms of mortality, as well as cognitive and motor disabilities. In addition to acute problems, the emergence of medium- and long-term consequences, such as the increased risk of dementia, has led scientists to analyze the ability of the brain to “repair itself”. To date, there is no unanimity on the problem in the scientific community: for studies that confirm the production of new neurons by the brain, other research claims the contrary.
The brain can’t cover itself
Anyone working on the development of new therapies to repair damaged brain tissue must consider the diversity of regenerative responses observed. While stroke causes known neural death and toxicity, it also triggers cell regeneration processes in some areas of the brain. In a study conducted at Jena University Hospital, a post-stroke neurogenesis process was observed in the hippocampus, a memory-critical area. The new cells, however, did not develop properly, but generated sketchy connections that worsened the motor and cognitive symptoms caused by stroke and increased tissue inflammation. This means that regenerative action, if it occurs in a disorderly manner, can even amplify the damage. According to some studies, this limited ability of the brain to repair itself triggers other “antechamber” processes of dementia. For example, it is assumed that stroke means that the chance of developing dementia in the next decade is doubled and that one third of patients experience severe cognitive impairment 6 months after the event. The data speak for themselves: in Italy, compared to 200,000 new cases of stroke per year, there are 50,000 new cases of related dementia.