Temporal Trends in Serum Homer1 Levels and Their Prognostic Implications in Aneurysmal Subarachnoid Hemorrhage: A Prospective Cohort Study

Background: Homer scaffold protein 1 (homer1) may harbor neuroprotective effects against acute brain injury. This study aimed to investigate the prognostic role of serum homer1 in human aneurysmal subarachnoid hemorrhage (aSAH). Methods: A total of 209 patients with aSAH and 100 controls were encompassed in this prospective cohort study. Serum homer1 levels were quantified at admission in all patients, on post-aSAH days 1, 3, 5, 7, 10, and 14 in 83 patients and at recruitments in controls. The modified Fisher scale (mFisher) and World Federation of Neurological Surgeons Scale (WFNS) were used for severity assessment. Glasgow Outcome Scale (GOS) scores of 1– 3 at post-aSAH 90 days indicated poor prognosis. Results: Serum homer1 levels of patients were abruptly elevated at admission, peaked at day 3, and afterwards decreased from day 5 until day 14 after aSAH, and were markedly higher during 14 days than those of controls. Serum homer1 levels were linearly and independently correlated with WFNS scores, mFisher scores, continuous GOS scores, ordinal GOS scores, poor prognosis risk and delayed cerebral ischemia (DCI) likelihood. DCI partially mediated association of serum homer1 levels with poor prognosis. The prognosis model was composed of the four independent predictors, that is serum homer1 levels, DCI, WFNS scores and mFisher scores. As demonstrated by a series of statistical methods, the model had a good performance. Conclusion: Serum homer1 levels are significantly elevated in acute phase after aSAH, and are strongly related to heightened bleeding intensity, poor 90-day prognosis and DCI. Nevertheless, associational mechanism of serum homer1 and poor prognosis mediated by DCI needs to be further deciphered. Keywords: aneurysm, subarachnoid hemorrhage, cohort study, mediation effect, homer scaffold protein 1