ENPP1 and myocardial infarction: Whereas previous studies had focused on immune cell ectonucleotidases in regulating post-MI wound healing (13–15), Li et al. demonstrate that cardiac fibroblast ENPP1 is the major regulator of extracellular ATP metabolism in the postinfarct heart and that cardiac fibroblast ENPP1-dependent signaling substantially affects post-MI remodeling (12).