POSTN and Stroke: Animal models have shown that periostin levels increase after ischemic stroke.10,11 The biomarker and prognostic role of periostin have also been studied in stroke in humans by He et al., but only for large-artery strokes.4 In their study, increased serum periostin levels on day 6 after the stroke were shown to be associated with poor prognosis in patients with major artery stroke.