Additionally, pro-NGF, pro-brain-derived neurotrophic factor (pro-BDNF), and brain-derived neurotrophic factor (BDNF) activate the p75 neurotrophin receptors (p75NTRs) and death receptor 6 (DR6), two members of the TNF super-family, to stimulate sympathetic nerve denervation [177,178,179,180,181,182,183], which occurs in the cardiac infarcted area and myocardium adjacent to the scar in myocardial infarction-induced HF. This evidence concerns the gene TNFRSF21 and hydrops fetalis.