WNT4 and myocardial infarction: Intriguingly, Wnt4, which had previously shown a strong upregulation in mouse adult hearts [30] and a slight increase in neonatal hearts [31] after cardiac injury, was downregulated in infarcted myocardium at 8 weeks post-MI (p = 0.02, median sham = 1.01 and infarct = 0.733) (Figure 5H).