DDIT3 and Myocardial fibrosis: It was shown that the T1DM rat model had reduced ejection fraction, elevated type III procollagen and laminin, increased expression of type I collagen, type III collagen and MMP-2/-9, wavy myocardial fibers and significantly increased collagen deposition, suggesting myocardial fibrosis and consequent cardiac dysfunction in this rat; further in vitro experiments showed that this phenomenon may be associated with activated ERS (increased expression of GRP78, GRP94, CHOP and ATF-4) (Hu et al., 2020).