Soluble active fragments of ACE2 appear in the urine in subjects with diabetes and chronic kidney disease (Mizuiri et al., 2011; Xiao et al., 2012; Park et al., 2013; Cherney et al., 2014), and are thought to be shed from proteolytic cleavage of the ACE2 ectodomain. Here, ACE2 is linked to chronic kidney disease.