COL1A1 and type 2 diabetes mellitus: The comparison between the T1DM and T2DM mice revealed an increase in myocardial fibrosis in the first group of animals, as confirmed with RT-PCR on freshly isolated CMs, in which the expressions of Col1a1, Col1a2 and Col3a1 were found to be higher in the T1DM mice compared to in the T2DM mice (Figure 3D).