Serum Ngb (Neuroglobin) Is Associated With Brain Metabolism and Functional Outcome of Aneurysmal Subarachnoid Hemorrhage.

Background and Purpose- Hypoxic-ischemic brain damage is a well-recognized physiopathologic mechanism after aneurysmal subarachnoid hemorrhage (aSAH). The Ngb (neuroglobin) is a hemoprotein predominantly expressed in the brain with a high affinity for oxygen. Relationship between serum Ngb level and brain metabolism in aSAH patients has not been investigated previously. Methods- Thirty-six consecutive severe aSAH patients (Glasgow Coma Scale score ≤8 on admission) with multimodal neuromonitoring and 36 matched healthy subjects were included. Serum Ngb level was analyzed in combination with other time-matched cerebral microdialysis parameters, brain tissue oxygen tension, and 12-month neurological outcomes. Results- Serum Ngb level was correlated positively with cerebral microdialysis parameters and brain tissue oxygen tension ( P<0.001). Poor functional outcome (modified Rankin Scale score >3) 12 months after aSAH was associated with higher Ngb level but independent of age, sex, and disease severity ( P<0.001). A similar association was found between high Ngb level and neuropsychological test results indicative of impairments in cognition, visual conceptualization, and frontal executive functions ( P<0.001). Conclusions- Ngb may be a potential biomarker for reflecting brain tissue oxygen tension, brain metabolism, and functional outcome in severe aSAH patients and merits further study in the context of aSAH.