The extravasated blood within the brain that occurs after a haemorrhagic stroke is simply detrimental to the neural tissue. This is associated with a number of different phenomena, some of which involve neutrophils, one population of white blood cells. Just as these cells can exacerbate damage to neural tissue, they can also nullify it - the second possibility American researchers looked at.

The scientists conducted their research on mice. In particular, they looked at interleukin 27 (Il-27), which modulates neutrophil activity. Under its influence, the cells of the immune system can somehow 'switch' from their destructive role to performing a function that supports the regeneration of neural tissue after a haemorrhagic stroke.

The role of interleukin 27 and neutrophils was demonstrated by the therapies to which scientists subjected mice after a haemorrhagic stroke. Those individuals injected with this substance recovered significantly faster. In contrast, those rodents given antibodies that blocked interleukin 27 activity showed a significantly slower recovery.

The action of interleukin 27 would be based on the fact that it would stimulate the activity in neutrophils of those genes that are associated with tissue healing processes - among others, genes encoding lactoferrin. The researchers noted that mice given Il-27 had increased activity of this gene, while those individuals given the Il-27-blocking antibody had decreased activity of these genes.

For the time being, the results described by the Houston scientists can be regarded rather as a curiosity. However, there is a possibility that thanks to the findings of these scientists, medicine will soon be equipped with new therapies for patients who suffer a haemorrhagic stroke.