Similarly to that observed in cardiac hypertrophy with fetal gene reprogramming of cardiomyocytes, such discrepancy could be explained by rejuvenation of cardiac sympathetic nerves as proposed by Kimura et al[32] with development of immature nerves expressing PSA-NCAM as we confirmed in this study in our myocardial infarction model. Here, NCAM1 is linked to myocardial infarction.