In Vitro Study On The Biological Properties Of A New Type EPC Capture Coronary Stent Material

BackgroundIn-stent restenosis (ISR) and thrombogenesis of percutaneouscoronary interventions (PCI) have been limiting its further development,re-endothelialization to repair the impaired intima is the key point tosolve the problems. Recent years, the focus of researches have been onthe endothelial progenitor cells (EPC) capture stents which could captureEPC. Our study group have designed a new type of EPC capture stentscoating with tripeptide named Arg-Gly-Asp (RGD),which have theability to capture EPC,with PEG-PLA-PGL as the stent bio-degradablepolymer. Our purpose was to deal with endothelialization delay ofdrug-eluting stents (DES). The new type stent coating material has beenproved to posses good cell compatibility. This study is aim to have afurther understand of other biological properties of PEG-PLA-PGL/RGD stents coating material on the basis of previous researches.ObjectivesEvaluate the blood compatibility of PEG-PLA-PGL/RGD stents invitro and discuss its influence on the stability of endothelial celladhesion, to provide more experimental data to the follow-up clinicalstudies.MethodsThe blood compatibility was evaluated by hemolysis assay, plateletadhesion experiments, anticoagulant time measurement and proteinadsorption test in vitro, with bare steel and PEG-PLA-PGL steel as the control group. PEG-PLA-PGL copolymer were divided into two groups:RGD group (covalently grafting synthetic tripeptide RGD) and controlgroup (copolymer), and the2groups of implants surface cultured humanumbilical vein endothelial cells, and in steady flow conditions observeand compare of different locations, different flow rates RGD peptidefixed in the T-tube and straight-tube on the surface of cell adhesionstability.ResultsThe results of blood compatibility in vitro:The hemolysis rate ofeach group was less than5%,which suggested they were all avirulent;APTT in three groups remarkable prolonged compared with plasmasample,showed anti-coagulant property of steel in three groups (P＜0.05).In contrast with bare steel, PEG-PLA-PGL steel had no apparentdifferences in any tests, meanwhile, PEG-PLA-PGL/RGD steel adsorbedless platelets but lager amount of albumin (P＜0.05). The control groupsand the RGD groups (in the T-tube at the position A (front fork), B (afterbifurcation), C (bifurcation)) under maximum flow rate (0.8m/s), theresult of EC residual rate showed that three groups exist significantdifference (P <0.05). In the RGD groups, the EC residual rate was morecompared with the control groups. However, both in the control groupsand the RGD groups, in T-type front fork position A, EC residual ratio isbetter than the position B and C (P <0.05).Conclusions:PEG-PLA-PGL/RGD stents have good blood compatibility in vitro;PEG-PLA-PGL/RGD stents could promote repair of intima and reducerestenosis by accelerating the re-endothelialization on the stents.