Because we used systemic deletion of the Mb21d1 gene in these experiments and given that SPP1, SFRP3, VIM, and MMP9 are also expressed in nonmyocyte cells in the heart, including immune cells, we determined the expression levels of these selected markers of heart failure in cardiomyocyte and nonmyocyte cells in the heart. This evidence concerns the gene MMP9 and heart failure.