Effects Of Atorvastatin On Endothelial Colony-forming Cells

Background：Endothelial impairments play important roles in the development of coronaryatherosclerosis, coronary in-stent restenosis and coronary in-stent thrombosis. The precursorcells of endothelial cells, endothelial progenitor cells (EPCs), play pivotal roles in thecoronary endothelial repair and reendothelialization. EPCs are not only an importantbiomarker of coronary artery diseases but also a new potential therapeutic target.EPCs include classical CFU-Hill/CD34~+KDR~+subpopulation and newly foundendothelial colony-forming cell (ECFC) subpopulation. CFU-Hill/CD34~+KDR~+subpopulation can not differentiate into mature endothelial cells, but they can providesuitable microenvironments for reendothelialization. ECFC subpopulation can not onlydifferentiate into mature endothelial cells, but also directly participate in reendothelializationand neoangiogenesis.Statins are not only the most successful lipid-lowering agents, but also exertlipid-independent pleiotropic effects, including endothelial protection, anti-inflammation,anti-oxidation, and anti-ischemia effects.Many studies have demonstrated that statins can significantly enhance the proliferation,anti-apoptosis, migration, and tube-forming abilities of classical CFU-Hill/CD34~+KDR~+EPCsubpopulation. However, so far, there are no reports about the effects of statins on theproliferation, anti-apoptosis, migration, and tube-forming abilities of ECFC EPCsubpopulation.Objective：Treat ECFC EPC subpopulation with different concentration of H2O2to observe theimpairment ability of oxidative stress on the proliferation, apoptosis, migration, andtube-forming abilities of ECFCs. Treat ECFC EPC subpopulation with atorvastatin toobserve the protective effects of statin treatment on the proliferation, apoptosis, migration,and tube-forming abilities of ECFCs after oxidative stress.Methods：ECFCs were cultured with standard protocol. Cells were treated with100、200、300、400μM H2O2, respectively, to establish the oxidative-damaged model. Cells were treated with0.01μM atorvastatin to observe the protective effects of statins on ECFCs. MTT assaywas used to evaluate the viability and proliferative ability of ECFCs. AO/EB andHoechst33342/PI double fluorescent stains were performed to measure the apoptotic ratio ofECFCs. Scratch method was used to evaluate the migration ability of ECFCs. Tube-formingassay was performed to measure the ability of ECFCs participating in reendothelializationand neoangiogenesis.Results：1. Oxidative stress significantly impaired the proliferative ability of ECFCs.2. Oxidative stress significantly increased the apoptotic ratio of ECFCs.3. Oxidative stress significantly impaired the migration ability of ECFCs.4. Oxidative stress significantly impaired the tube-forming ability of ECFCs.5. Atorvastatin significantly improved the proliferative ability of ECFCs.6. Atorvastatin significantly decreased the apoptotic ratio of ECFCs.7. Atorvastatin had no effect on the migration ability of ECFCs.8. Atorvastatin significantly improved the tube-forming ability of ECFCs.Conclusions：Present study provided new experimental evidences of the effects of statins on ECFCsubpopulation of EPCs, which may expand our understanding from conventionalCFU-Hill/CD34~+KDR~+subpopulation to newly found ECFC subpopulation of EPCs andmay facilitate the study of pleiotropic effects of statins in clinical therapies of coronaryartery diseases.