The sex of a patient can affect the outcomes of several cardiovascular diseases, and men generally tend to experience earlier episodes of cardiovascular diseases compared with women. The progression of atherosclerosis during hyperlipidemia can be induced by reactive oxygen species (ROS) and oxidized-low-density lipoprotein (ox-LDL). By contrast, bone marrow (BM)-derived endothelial progenitor cells (EPCs) have been reported to serve a protective role against atherosclerosis. The aim of the present was to compare the effects of sex under conditions of hyperlipidemia on different populations of EPCs, and to identify the potential underlying mechanisms.

Ambient fine particulate matter (PM) serves an important role in the development of cardiovascular disease, including atherosclerosis. Antioxidant N-acetyl cysteine (NAC) has protective effects in the cardiovascular system. However, it is unknown if NAC prevents PM-potentiated atherosclerosis in hyperlipidemia. Low-density lipoprotein (LDL) receptor knockout mice were pretreated with 1 mg/ml NAC in drinking water for 1 week and continued to receive NAC, high-fat diet and intranasal instillation of PM for 1 week or 6 months. Blood plasma was collected for lipid profile, oxidized (ox-)LDL, blood reactive oxygen species (ROS) and inflammatory cytokine (TNF-α, IL-1β and IL-6) measurement. Blood cells were harvested for endothelial progenitor cell (EPC) population and intracellular ROS analysis. Murine aorta was isolated for atherosclerotic plaque ratio calculation. NAC treatment maintained circulating EPC level and significantly decreased blood ox-LDL and ROS, inflammatory cytokines, mononuclear and EPC intracellular ROS levels as well as aortic plaque ratio. NAC prevented PM-potentiated atherosclerosis by inhibiting plasma ROS-induced ox-LDL elevation, mononuclear cell and EPC intracellular ROS-induced circulating EPC reduction and inflammatory cytokine production.