The injection of miRNA-conjugated (miR21-5p) PEG-hydrogels decreased scar size, IZ, BZ, LVESD, LVEDV, and the expression of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP), while increasing LVSV (left ventricular stroke volume) to levels pre-MI in porcine models [84]. The gene discussed is NPPA; the disease is myocardial infarction.