S100 as a marker of acute brain ischemia: A systematic review

Background: Studies show S100 as a possible acute ischemic stroke (AIS) marker. Objectives: Determine (1) whether S100 serum concentrations correlate with stroke symptom onset, infarction volume, stroke severity, functional outcome, or length of hospital stay; (2) whether S100 serial measurements are useful markers for ongoing brain ischemia, and (3) whether S100 levels at various time intervals are higher in AIS patients than controls. Methods: Literature was searched using OVID and MEDLINE from January 1950 to February 2007, and all relevant reports were included. Results: Eighteen studies (1,643 patients) satisfied entry criteria. S100 peaks from symptom onset between 24 and 120 h with significantly raised values measured from 0 to 120 h. Higher S100 values indicated significantly larger infarction volumes, more severe strokes, and worse functional outcome. There was a significant difference in S100 levels between AIS patients and controls. Conclusion: Peak values after stroke onset varied. S100 was significantly increased after stroke onset, and correlates with infarct volume, stroke severity, and functional outcome, and was a possible marker for ongoing ischemia. Its serum concentration during acute stroke is a useful marker of infarct size and long-term clinical outcome.