The role of darbepoetin treatment on improvement of atherosclerosis in Apolipoprotein E knock-out (apoe knock-out) mice and proteomic analysis of differential protein expression in atherosclerosis

Atherosclerosis and atherosclerosis related complications are the major cause of morbidity and mortality in the world. Vascular injury in response to inflammation, enhanced oxidant stress promotes endothelial dysfunction and leads to atherosclerotic lesions. Low-dose treatment with the long-acting recombinant human erythropoietin analogue darbepoetin-alpha may be a potential therapeutic tool for endothelial injury and atherosclerosis.ApoE-/- mice were used as atherosclerotic mice model in this study. Atherosclerosis and plaque formation were monitored histochemically.Darbepoetin-alpha was injected intraperitoneally at a dose of 0.1 microgram/kg in early and late stage of atherosclerosis. The results of this group were compared with the results of control group that injected salin instead of darbepoetin-alpha.The levels of lipid profile (total cholesterol, triglyceride), inflammatory (CRP, IL-6 and histamine), endothelial injury (ICAM-1 and selectin) and oxidative stress markers (lipid peroxidation and protein oxidation) were significantly increased in atherosclerotic groups when compared to control group. It was shown that darbepoetin-alpha had no significant effects on serum lipid profile, or markers of inflammation and endothelial injury. However, darbepoetin-alpha significantly decreased 8-isoprostane levels and protein carbonyl content in atherosclerotic groups.Serum proteomic analyses were performed using surface- enhanced laserdesorption/ionization-time of flight mass spectrometry (SELDI-TOF- MS). Proteomic analysis of serum samples of C57BL/6 and ApoE-/- mice showed that a total of 107 peptid/protein clusters were significantly changed. Serum proteomic analyses were also performed in the darbepoetin-treated and non-treated ApoE-/- mice groups. 145 peptid/protein clusters had statistically significant differences in their peak intensities between the darbepoetin-alpha treated and non-treated groups.Long term darbepoetin-alpha treatment reduced oxidative stress in ApoE-/- mice, but not lipid profile, inflammation and endothelial injury. On the other hand proteomic study contributes to understanding the changes in serum peptid/protein profiles during atherosclerosis development and may inform discovery of new biomarkers for early diagnosis of atherosclerosis.