NPPA and heart failure: At the age of six months, these pathological changes caused by cardiac-specific expression of Cre recombinase were also accompanied by a significant increase in Nppa (p < 0.01), Nppb (p < 0.05) and Myh7 (p < 0.05) mRNA levels in the left ventricle, which are three classic biomarkers of cardiac failure (Figure 2G).