NOS3 and diabetes mellitus: Patients with overt coronary artery disease or peripheral arterial obstructive disease have multiple vascular risk factors such as dyslipidemia [26], hypertension [27], or diabetes [28] that lead to impaired NO bioavailability by multiple mechanisms such as endothelial nitric oxide synthase (eNOS) uncoupling, increased NO breakdown by reactive oxygen species, or increase in asymmetric dimethylarginine (ADMA) [29].