APLN and hydrops fetalis: In HF it has been shown in several studies that apelin levels are decreased in human patient plasma (Földes et al., 2003; Chong et al., 2006; Francia et al., 2007), in tissues from a number of rat models (Iwanaga et al., 2006; Koguchi et al., 2012), in mouse doxorubicin-induced cardiotoxicity, and in a dog model (Wang et al., 2013a).