What is more, by preventing the downregulation of miR-133a in a mouse model of TAC-induced cardiac remodeling, the downregulation of Kv4-encoded Ito, f was abolished despite the presence of abnormal repolarization, because miR-133 potentially enhanced the expression of Kv4-encoded Ito, f (Kcnip2), whose upregulation may decrease the content of collagen in fibroblasts and prevent abnormal Ito, f (Matkovich et al., 2010). This evidence concerns the gene KCNC1 and persistent truncus arteriosus.