Role Of SDF-1α For Mediating Endothelial Progenitor Cells In Aneurysm Repair And Its Mechanism

The rupture of intracranial aneurysm is the main cause of subarachnoid hemorrhage, whichhas the clinical features of high mortality and morbidity. The disease has brought greateconomic burden to the family and society. With the development of medical sciences, theadvancement of interventional and regenerative medicine had shed new lights on thetreatment of intracranial aneurysms. In the intervention field, the endovascular treatmenthad moved from the beginning of singular coiling to the current treatment with flowdiversion devices. Flow diverter can reconstruct the lesional lumen， alter thehemodynamics of aneurysm, and provide a scaffold for intima growth across the aneurysmneck in order to isolate the aneurysms. In the regenerative field, use of endothelialprogenitor cells has brought a prosperous future for the aneurysm treatment. In our earlierexperiments, we found that bone marrow-derived EPCs contributes to the aneurysm repairafter establishement of elastase-induced saccular aneurysm model and participate in theneointima formation in the aneurysm neck and parent artery after flow diverter treatment.In the successive research, we will investigate the mechanism of endothelial repair of EPCsfrom the aspect of chemokine stromal derived factor-1α(SDF-1α) and investigate therole of SDF-1/CXCR4axis during the process of neointima formation in rabbit saccularaneurysm after flow diverter treatment in different time points.The role and mechanism of SDF-1αin homing of EPCsAbstract Objective To investigate the role and mechanism of SDF-1α in the homing ofEPCs. Methods Bone marrow mononuclear cells of ten rabbits were isolated cultured withEGM-2MV medium in flasks coated with fibronectin. Migration assay was tested withBoyden Chamber with different concerntration of SDF-1α. Western blot was used toanalysed the expression of protein including VE-cadherin, E-selectin and P-selectin.Results The cultured EPCs confirm the cells with biological behavior with took upDil-ac-LDL and combined with FITC-UEA-1lectin and showed positive CD34, CD133,and VEGFR-2with immunocytochemistry. The migration ability was different withdifferent conserntration of SDF-1α. With the increase of conserntration of SDF-1α,moreEPCs migrate into the other side and the concerntration of500ng/ml had the highestmigration ability. The expression of VE-adherin increased with the conserntration ofSDF-1α. Conclusion EPCs with biological behavior can be acquired from bone marrow. SDF-1α can attract the EPCs and stimulate EPCs to express VE-cadherin. Expression of SDF-1α in the wall of saccular aneurysm inrabbitsAbstract Objective To investigate SDF-1expression at the early stage of modelestablishement. Methods Saccular aneurysm was established with porcine pancreaticelastase, Sdf-1α protein was investigated in the aneurysm wall with Western blot andSDF-1α mRNA was investigated with realtime PCR;Location of protein expression in thetissue was investigated with immunohistochemistry(IHC). Results IHC results show thatSDF-1α was expressed in the neointima and most significantly on day14after modelestablishement; realtime PCR results showed that SDF-1αmRNA was expressed stronglyon day7, Western blot results showed that SDF-1α expressed most highly on day14.Conclusion SDF-1α can be expressed in the wall of saccular aneurysm in the rabbits, andexpressed significantly on day7to14. rhSDF-1α accelerates reendothelialization of neointimaformation in saccular aneurysm after flow diverter treatmentAbstract Objective To investigate the role of rhSDF-1α in the neointima repair ofsaccular aneurysm in rabbits after flow diverter treatment. Metholds Twenty New ZealandWhite Rabbits were used to establish saccular model with porcine pancreatic elastase.Three weeks later, flow diverter of Tubridge was implanted. All the treated models weredivided into two groups, one using rhSDF-1αintravenously50ug/mg per day and the otherusing saline as control group. Morphology was investigated with SEM on neointimaformation2weeks and4weeks after FD treatment.Expressions of Tie2, CD34,KDR,VE-cadherin were examined with realtime PCR. Results SEM showed that in therhSDF-1αgroup,there are more endothelial-like cells on the neointima at week2and4weeks after flow diverter treatment. In the experiment group and control group, theendothelial-like cells reched40and13per high power field two weeks after flow diverter treatment and reached104and60cells per high power field4weeks after FD treatmentunder electron scanning microscope. There are significant differences between theendothelial markers of Tie2, KDR and VE-cadherin（P<0.05）. Conclusion Systemicdelivery of rhSDF-1αpromotes the endothelial repair and facilitates the endothelializationof aneurysm neck after flow diverter treatment. AMD3100accelerates reendothelialization of neointimaformation in saccular aneurysm after flow diverter treatmentAbstract Objective AMD3100acts as antagonist of CXCR4, this section aims toinvestigate the role of AMD3100in the neointima repair. Metholds Ten New ZealandWhite Rabbits were used to establish saccular model with porcine pancreatic elastase.Three weeks later, flow diverter of Tubridge was implanted. All the treated models weredivided into two groups, one using AMD3100subcutaneously3ug/mg per day and theother using saline as control group. Morphology was investigated with Masson and hardtissue section on neointima formation2weeks and4weeks after FD treatment.ResultsSEM showed that in the AMD3100group, there are more endothelial-like cells on theneointima at week2and4weeks after flow diverter treatment. In the experiment groupand control group, the endothelial-like cells reched40and13per high power field twoweeks after flow diverter treatment and reached92and60cells per high power field4weeks after FD treatment under electron scanning microscope. The intima in theexperiment group was more intact than that in the control group. Conclusions Interval useof AMD3100promotes the endothelial repair and facilitates the endothelialization ofaneurysm neck after flow diverter treatment.