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.