These observations of favourable effects of serelaxin on the phenotype of the diabetic heart, without gross changes in heart weight index, are consistent with other cardioprotective interventions in the diabetic heart, including nitroxyl donors17, and both the endogenous antioxidant coenzyme Q10 and the “gold standard” therapy for the cardiovascular complications of diabetes, an angiotensin-converting-enzyme (ACE) inhibitor16. Here, ACE is linked to diabetes mellitus.