POSTN and myocardial infarction: The results revealed that the mRNA levels of fibrotic genes, such as collagens and Periostin (Postn) were greatly increased in the infarct area of the mouse heart after MI (Fig. 2a, Supplementary Fig. 3a), peaked at 7 days after MI and then gradually decreased; however, the levels in the infarcted area remained high even on day 28 after MI.