Therefore, here we performed Western blot, ELISA, and radioimmunoassay experiments in order to measure the expression of DPP4, NPY, and SP at the protein level in interventricular septum samples from failing human hearts (patients with ischemic cardiomyopathy (ICM) or dilated cardiomyopathy (DCM)) and also from healthy control (CON) hearts (detailed patients’ characteristics in Supplementary Tables S1 and S2). This evidence concerns the gene DPP4 and familial dilated cardiomyopathy.