In both diabetic ventricles, we found brain natriuretic peptide (BNP) immunoreactivity; however, there was no difference in BNP concentration in ventricular tissue homogenates between T1D and control groups (p > 0.7, Kruskal–Wallis test, three hearts in the control group and three hearts in the diabetic group, Figure S1, Supplementary Materials). This evidence concerns the gene NPPB and type 1 diabetes mellitus.