Candidate molecular predictors of outcome after aneurysmal subarachnoid haemorrhage: a systematic review of haemoglobin metabolism, inflammation and oxidative injury pathways.

Aneurysmal subarachnoid haemorrhage (aSAH) is a devastating form of stroke associated with significant morbidity and mortality. Very little is known about the predictors of poor outcome and the pathophysiological mechanisms underlying neurological injury following aSAH. Three molecular pathways have been shown to be important: haemoglobin metabolism, inflammation and oxidative injury. The aim of this review is to use a systematic approach to identify a panel of key genes within these three pathways in order to focus future studies investigating predictors of poor outcome and the mechanisms of neurological injury following aSAH. Manual searching and bioinformatic mining tools were used. Studies of experimental or human SAH were included, and outcome was broadly defined to include all encountered readouts such as mortality, neurological scores, and neuropathological markers of tissue damage. If two or more molecules belonged to the same biochemical pathway, this pathway was examined in detail to identify all its components, which were then searched individually for any evidence of association with outcome using the same broad definition as before. This resulted in the identification of 58 candidate genes within the three pathways of interest (haemoglobin metabolism, inflammation and oxidative injury) potentially linked to outcome after aSAH.