In human coronary arteries presenting atherosclerosis, apelin expression is upregulated, and in atherosclerotic plaques both apelin and its receptor can be found (it is not known if this is an antagonistic response to angiotensin II signaling, or due to some pathological mechanisms of plaque formation), but the concentrations of circulating apelin are lower in patients with coronary artery disease, especially in symptomatic cases [78,87]. The gene discussed is APLN; the disease is atherosclerosis.