P4HB and myocardial infarction: As there is increasing evidence for the gut microbiota as a determinant of myocardial infarction (Lam et al., 2012), and because we found that the presence of a gut microbiota enhances angiotensin II-induced cardiac fibrosis (Karbach et al., 2016), we took advantage of the GF mouse model to explore whether the host colonisation status impacts on ventricular function and myocardial PDI expression under ischemic conditions in the LAD ligation model.