GDF11 and cardiac hypertrophy: Though myostatin has an established, anti-hypertrophic effect on muscle (Tobin and Celeste 2005; Carnac et al. 2007; Morissette et al. 2009; Rodriguez et al. 2014), including a direct regulatory effect on cardiomyocytes (Lee and McPherron 1999; Morissette et al. 2006; McKoy et al. 2007; Biesemann et al. 2014), it still remains unclear whether GDF11 has the same, or distinct, effects on cardiac hypertrophy (Smith et al. 2015; Fan et al. 2017).