It is reported that periodontitis attenuates endothelium - dependent vasodilation in rats [44, 45].The causes were increased systemic inflammatory biomarkers (CRP and IL-6), increased production of vascular superoxide free radicals, worsening lipid status, and decreased expression of vascular nitric oxide synthase-3 (NOS-3) [45]. The gene discussed is NOS3; the disease is periodontitis.