An immunological approach to cerebral ischemia (I). Immune cells and adhesion molecules.

Ischemic stoke is a major cause of death and an important source of disability in industrialized countries. Since there is no ideal treatment for cerebral ischemia, any approach aiming to limit the devastating consequences of the ischemic process is justified. Concerning immune responses, it has become clear in the latest years that actors of the immune system are involved in multiple and various neurobiological processes such as cerebral ischemia, neurodegeneration, neuroprotection and neuroregeneration. An immunological approach to cerebral ischemia can distinguish, besides the implication of inflammation in the developing of atherothrombosis thus leading to stroke, the clear involvement of immune cells and mediators in processes continuing the initial stage of ischemia, having consequences on recovery or lesion extent. Cerebral infarctions develop within minutes to hours of cessation of the cerebral blood flow, but may expand over subsequent days. There is increasing evidence that leukocytes, cytokines, cell adhesion molecules, and other immune mediators contribute to secondary infarction growth, but inflammatory cytokines are also involved in signaling pathways leading to neuroprotection related to ischemic pre-conditioning. The aim of this review is to show some aspects concerning the complex and diverse functions of immune modifications occurring in cerebral ischemia. This first part will focus on the involvement of immune cells, adhesion molecules and immunological transcription factors in the development of ischemic lesion.