By double immunofluorescence for CD31 and α-smooth muscle actin-positive (α-SMA), we found comparable densities of coronary arteries (CD31+/α-SMA+) and capillaries (CD31+/α-SMA−) between WT and Dusp6-deficient hearts at sham-operated and post-MI (Supplementary Fig. 3e, f). The gene discussed is PECAM1; the disease is myocardial infarction.