Moreover, a not FDA-approved Digoxin functional and structural analogous isolated from milkweed plants of the family Asclepiadoideae [164], namely Calotropin, is active over HF by modulating SIRT1/FOXD3/SERCA2a pathway [165], thus supporting the relevance of this pathway in the action mechanism of cardiac glycosides. Here, SIRT1 is linked to hydrops fetalis.