Particular significance, has been attributed to over production of Mitochondrial ROS in vascular endothelial and smooth muscle cells due to the ability of its by-products, superoxide and H2O2, to increase the gene expression of cytokines (TNF-α, IL-1 and IL-6), adhesion molecules (ICAM, VCAM) and pro-inflammatory enzymes (iNOS, COX-2) resulting in accelerated senescence and endothelial dysfunction [154,155]. Here, TNF is linked to endothelial dysfunction.