RUNX1 and myocardial infarction: Interestingly, whilst intravenous injection of a cardiotropic adeno-associated virus serotype 9 expressing a shRNA targeting Runx1 (AAV9-Runx1-shRNA) produced a reduction in infarct size at 7-days post-MI, measured by Sirius red staining on fixed heart slices, direct myocardial injection of adenovirus-mediated Runx1-shRNA did not show the same effect of reducing infarct size (Martin et al. 2023).