The Effects Of Simvastatin On The Proliferation?Migration?and Adhesion Of Endothelial Progenitor Cells Incubated With Lipopolysaccharide

Background:Sepsis continues to be a major cause of morbidity and mortality worldwide. Preclinical and clinical sepsis studies have shown that the acute systemic inflammatory and procoagulant response results in structural and functional alterations in the endothelium. The endothelial cells (ECs) play a pivotal role in the progression of sepsis; the ECs are not only the participant of inflammatory reaction, but also the first damaged target cells. The dysfunction of ECs is a critical event in the initiation of organ dysfunction caused by sepsis.Recent studies suggested that the injured ECs could be regenerated by circulating bone marrow-derived progenitor cells called endothelial progenitor cells (EPCs), which had capabilities to mobilize from bone marrow with homing to foci of injuries and to differentiate into mature ECs to ameliorate the dysfunction of ischemic organs caused by sepsis. The impairment of EPCs caused by severe inflammation may contribute to the progression of organ dysfunction. Circulating endothelial progenitor cells may be an important mechanism of vascular repair, and thus shows significant promise for prognostic and therapeutic strategies in critical illness, namely sepsis and sepsis-related organ dysfunction. Many studies have convincingly demonstrated that simvastatin benefit for sepsis,and could promote the function of EPCs.but there no evidence about the effects of simvastatin on the EPCs incubated with LPS.Objective:1?To separate EPCs from human umbilical cord blood (HUCB).2?To investigate the variation of the proliferation?adhention?migration and apoptosis of EPCs when incubated with LPS.3?The effects of simvastatin at different concentration on the functions of EPCs when added before or after the EPCs incubated with LPS in vitro.Methods:Total mononuclear cells(MNCs) were isolated from human umbilical cord blood by Ficoll density gradient centrifugation,and then the cells were plated on fibronectin-coated culture dishes. After 7 days culture, attached cells were isolated and assessed with a laser scanning confocal microscope. EPCs divided to different group:control group:EPCs were cultivated with standard EGM-2MW fluid for 48hr; LPS group:EPCs were cultivated with standard EGM-2MW fluid plus LPS(100 ng/Ml) for 48hr;simvastatin grup:EPCs were cultivated with standard EGM-2MW fluid add simvastatin 1.0?mol/L for 48hr;test group:first EPCs were incubated with standard EGM-2MW fluid and LPS(100 ng/ml)/simvastatin of different concentrations (simv0.1:add simvastatin 0.1?mol/L, simv1.0:add simvastatin 1.0?mol/L, simv10.0:add simvastatin 10.0?mol/L) for 24hrs then addde simvastatin of different concentrations (simv0.1:add simvastatin 0.1?mol/L, simv1.0:add simvastatin 1.0?mol/L, simv10.0:add simvastatin 10.0?mol/L)/LPS(100 ng/ml).The proliferation, adhesion and migration of EPCs were detected with MTT assay, Transwell chamber assay after 48hrs respectively.And the influences of LPS and simvastatin on EPCs'proliferation, adhesion?migration and apoptosis were evaluated.Results:Incubated with LPS the proliferation of EPCs were decline significantly (P=0.009),the adhesion and migration of EPCs were also descended,but there was no significance (P=0.279?P=0.056),the apoptosis rate of EPCs were increased significantly.When added simvastatin the proliferation, adhesion and migration of EPCs were all improved,there are some difference for difference concentration of simvastatin.There were hardly any improvment in the proliferation, adhesion and migration of EPCs when added simvastatin of 0.1?mol/L (P=0.687?P=0.501?P=0.683 respectively), EPCs' proliferation was improve significantly when incubated with simvastatin of 1.0?mol/L compared with LPS group(P=0.017),while the adhesion and migration were also improved but there was no significance(P=0.064?P=0.069 respectively). When incubated with simvastatin at the concentration of 10.0?mol/L the the proliferation?adhesion and migration of EPCs were all improved significantly (P=0.00, P=0.002, P=0.00 respectively)compared with LPS group,and the adhesion and migration of EPCs were ameliorated significantly even compared with the EPCs cultivated with standard EGM-2MW fluid (P=0.039,P=0.000 respectivly).Incubated with simvastatin there were no significant changes on the EPCs function of proliferation, adhesion and migration. When EPCs were incubated with standard EGM-2MW fluid added simvastatin of different concentrations (simv0.1:add simvastatin 0.1?mol/L, simv1.0:add simvastatin 1.0?mol/L, simv10.0:add simvastatin 10.0?mol/L) for 24hrs then addde LPS(100 ng/ml).The proliferation, adhesion and migration of EPCs all improved compare with the LPS group,but lower than the control group;the apoptosis were all decreased compare with the LPS group,but higher than control group and simvastatin group still.Conclusion:LPS could cut down the proliferation of EPCs sharply while the adhesion and migration were decline in some degree when incubated with EPCs.Simvastatin could improve the declined proliferation, adhesion and migration of EPCs which incubated with LPS first.When incubated with simvastatin first there were some profect function on the effect of LPS on EPCs...