This may be particularly relevant to the clinical setting given the increasing interest in the cardiovascular actions of established GLP-1 therapies in diabetic patients with heart failure [1, 25, 26], particularly DPP-4 inhibitors, which inhibit the breakdown of native GLP-1(7–36)amide, thereby significantly reducing circulating levels of its breakdown product, GLP-1(9–36). Here, GCG is linked to heart failure.