[Pathophysiology of focal cerebral ischemia: fundamental aspects and its projection on clinical practice].

Aim: The aim of this study is to review the basic aspects of focal cerebral ischemia as a fundamental element in clinical practice and of neuroprotective strategies.

Development: Ischemia triggers several different responses in nerve tissue which, according to the degree of energetic limitation, can be adaptive or lead to cell death due to necrosis or apoptosis. Establishing these processes is a complex task and the mechanisms involved have still not been fully explained; this is made more difficult by the fact that many of them are simultaneous and also because of the implications they may have, not only in cell death but also in the adaptation of the neurons that suffered ischemic stress and survived. We outline the foundations for understanding the physiopathological phenomena at work in ischemia: neuronal stress and death, and the reaction of the macroglial and microglial cells. This is also illustrated by original images from research into cell response to ischemia at a pre-clinical level in an experimental model of focal cerebral ischemia in rats, evaluated using, for example, hematoxylin-eosin and immunohistochemical techniques for several cell markers.

Conclusions: Cell death in ischemia is a complex phenomenon that can have two different outcomes: necrotic death or apoptotic death. Basic knowledge of the pathophysiology of ischemia and of the response of microglial and macroglial cells is the foundation for elaborating neuroprotective-type strategies, which must not only be oriented towards preventing acute cell death, but also later modes of cell death or strengthening the surviving tissue.