COL3A1 and myocardial infarction: To assess the production of fibrotic and contractile proteins in the myocardium after MI, RT-qPCR analyses were performed for collagens (Col1A2 and Col3A1), periostin (Postn), smooth muscle cell actin (Acta2) and transforming growth factor beta 1 (Tgfb1) (Fig. 7a).