The past and future of neuroprotection in cerebral ischaemic stroke

Following the realization that cerebral tissue may survive for hours after an ischaemic insult, several agents with neuroprotective properties in small-animal models of cerebral ischaemia have been tested in patients with acute ischaemic stroke (AIS). Initial attempts at translating the positive effects of these agents from animal models to patients were unsuccessful, possibly as a result of poorly planned experiments in models of ischaemia, and/or clinical trials of AIS that were not optimized to show a positive effect. Newer neuroprotective agents that are believed to act later in the ischaemic cascade may offer a greater chance of success. However, before these agents can be introduced into clinical practice they must undergo assessment in rodent and large-animal models of AIS and, in particular, the dose-response relationship and the treatment time window should be defined. This should be followed by evaluation in carefully designed clinical trials of adequate power, involving subjects receiving an appropriate dose within an optimum time window following the onset of symptoms. There is hope that such careful strategies may guide continued progress in neuroprotective drug development.