Serum S-100 Protein, Relationship to Clinical Outcome in Acute Stroke

Abstract

The clinical significance of serum S-100 protein, a protein released by damaged brain tissue, was assessed in patients with acute ischaemic or haemorrhagic stroke and matched controls. Serum S-100 protein concentration was significantly elevated in patients with ischaemic stroke [median (SQR): 0·27 (0·09)μg/L, n = 68] and haemorrhagic stroke [0·43 (0·23)μg/L, n=13] compared to controls [0·11 (0·03)μg/L, n = 51, P<0·0001]. Although patients with haemorrhagic stroke had higher serum S-100 concentrations compared to patients with ischaemic stroke, this was not quite statistically significant. Serum S-100 concentrations were related to infarct size, large (total anterior circulation) infarcts concentrations having the highest [0·40 (0·22) μg/L], and small vessel (‘lacunar’) infarcts concentrations having the lowest [0·20 (0·06)μg/L, P<0·0005] concentrations. S-100 protein concentration was also significantly related to clinical outcome at three months measured using three disability and handicap scales ( n = 81): modified Barthel index ( rs=–0·285, P = 0·01), modified Rankin score ( rs = 0·313, P = 0·004) and Lindley score ( rs = 0·262, P = 0·018) with high values associated with poor clinical outcome. Similarly high values of serum S-100 protein were observed in patients who died or were discharged to an institution [median (SQR): 0·63 (0·29)μg/L and 0·37 (0·13)μg/L, respectively] compared to those who were discharged home [0·26 (0·11)μg/L, P = 0·13]. The present study suggests measurement of serum S-100 protein could be a useful prognostic marker of clinical outcome in acute stroke. Whether S-100 concentrations can be altered by therapeutic intervention in acute stroke remains to be elucidated. Indexing terms: acute stroke/serum S-100/Barthel index/Rankin scale.