GDF11 and cardiac hypertrophy: However, there is some controversy about the pathophysiological role of GDF11 in aging-associated organ damage.9–11 Indeed, Smith et al. reported that GDF11 did not rescue cardiac hypertrophy in aged mice.9 Moreover, GDF11 has been shown to increase rather than decrease with age in both rats and humans, and to inhibit toxin-damaged muscle regeneration in old mice.10,11