The results of the current study are consistent with the notion that cardiac hypertrophy is preceded by sharp upregulation in the mRNA expression levels of profibrotic markers (TGF-β, SMAD-2, SMAD-3, SMAD-4, and NF-κβ) and marked downregulation of antifibrotic SMAD-7 mRNA and let-7b miRNA. Here, SMAD4 is linked to cardiac hypertrophy.