الفهرس | Only 14 pages are availabe for public view |
Abstract Atherosclerotic heart disease is a chronic life-threatening disease, which is characterized by reduced blood supply to the heart as a result of the accumulation of atheromatous plaques within the walls of the arteries that supply the myocardium. Progressive atherosclerosis in the coronary arteries may lead to intimal thickening and eventual artery occlusion. Coronary artery occlusion can cause acute myocardial ischemia as a result of reduced oxygen supply or increased oxygen demand. Convincing evidence indicates that atherosclerosis is associated with endothelial dysfunction at the early stage of the disease process. More recently, it has become clear that circulating endothelial progenitor cells are an alternative mechanism for maintenance and repair of the endothelium, these cells are recruited from the bone marrow, circulate in the peripheral blood, and can differentiate into mature cells with endothelial characteristics. Postnatal vasculogenesis is the formation of new blood vessels from bone marrow-derived endothelial progenitor cells (EPCs). This process is regulated, in part, through chemokine signaling gradients that guide these EPCs to areas of ischemia/injury. Chemokines, a cytokine subset, are inflammatory mediators specifically involved in trafficking of many different cell types including immune cells and stem cells. Recent studies have shown that ionizing radiation (IR) can affect CXC chemokine expression in human fibroblasts. |