Immunoblot analysis showed increased monocyte chemoattractant protein-1 levels as a DCM biomarker (Dobaczewski & Frangogiannis, 2009) in cardiac tissues from OLETF rats, whereas levels of TGF-β1, collagens I and III, and fibronectin were similar to those in LETO rats, likely due to the old age of the animals. This evidence concerns the gene CCL2 and familial dilated cardiomyopathy.