Specifically, ICM endothelial cells show up-regulation of genes like POSTN, CX3CL1, and BGN, which are associated with apoptosis, cardiac function, and adaptive remodelling post-myocardial infarction.46–48 This unique ICM endothelial signature, distinct from gene expression profiles in other end-stage HF and in ICM cardiomyocytes, suggests endothelial-derived factors as potential biomarkers or therapeutic targets. Here, POSTN is linked to hydrops fetalis.