GREM1 and hydrops fetalis: Characterization of the OPN and Grem1 proteins expression changes in cardiomyocytes at the early stages of ischemic HF, crucial for extending the knowledge on the OPN and Grem1 roles in the earliest events within failing cardiomyocytes in ischemic HF pathogenesis and searching for the novel diagnostic or therapeutic targets, remains principally out of scope in these studies.