Cerebral Hemodynamic Changes After Carotid Endarterectomy And Molecular Pathological Study Of The Carotid Atherosclerotic Plaques

Background:Carotid atherosclerotic stenosis is the reason for 15%-20%of brain ischemic stroke.The pathogenesis includes the disorder of hemodynamics caused by stenosis and stroke caused by embolus.CEA is the most effective operation for CAS.CEA can resect the atherosclerotic plaque that causes stroke.But the change of brain hemodynamics is indefinite.Recent research have found the Legumain expressed more in the atherosclerotic plaque.The Legumain plays a role during the AS progression.There is no systemic in vivo research on the distribution and expression of Legumain in CAS plaque.PartⅠ.Cerebral Hemodynamic Changes after Carotid EndarterectomyObjective To evaluate cerebral hemodynamic changes of symptomatic and asymptomatic patient groups before and after CEA by means of TCD.Methods 32 symptomatic patients underwent CEA for≥50%internal carotid artery stenosis,and 8 asymptomatic patients underwent CEA for≥80%internal carotid artery stenosis from Jan 2007to Jan 2009.TCD was done 1-3 days before CEA,and 8-10 days after CEA.MFV and PI of MCV,ACA,and PCA were evaluated.Results 1.On the ipsilateral side and contralateral side of symptomatic patients, MFV and PI of MCA and ACA increased significantly after CEA.MFV of PCA decreased significantly,with nonsignificant changes in PI after CEA. 2.On the ipsilateral side of asymptomatic patients,MFV of PCA decreased significantly,with nonsignificant change in PI after CEA.On the bilateral side of asymptomatic patients,nonsignificant changes were seen on MFV and PI of MCA and ACA after CEA.Conclusion Most symptomatic patients show increases of cerebral hemodynamics after CEA.The hemodynamic response of most asymptomatic patients to endarterectomy was negligible.PartⅡ.Cerebrovascular Reserve Changes after Carotid EndarterectomyObjective To evaluate cerebrovascular reserve of symptomatic and asymptomatic patient groups before and after CEA by means of TCD.Methods from Jan 2007to Jan 2009,10 symptomatic patients underwent CEA for≥50%internal carotid artery stenosis,8 asymptomatic patients underwent CEA for≥80%internal carotid artery stenosis,and 8 normal controls were compared. TCD was performed on 1-3 days before CEA,and 8-10 days after CEA.The cerebrovascular reserve was evaluated with TCD ultrasonography for hypercapnia induced by breath holding,which affected the mean blood velocity in MCA.Results 1.The BHI of the ipsilateral side in symptomatic patients was significantly lower than that in asymptomatic patients and normal controls before CEA.There were no significant differences between the BHI of the contralateral side in symptomatic patients with that in asymptomatic patients and normal controls before CEA.There were no significant differences between the BHI of the bilateral side in asymptomatic patients with that in normal controls before CEA. 2.The BHI of the ipsilateral side in symptomatic patients improved significantly after CEA as compared with preoperative BHI,however,There was no significant change between preoperative BHI with postoperative BHI in the contralateral side of symptomatic patients.There was no significant change between preoperative BHI with postoperative BHI in the ipsilateral side of asymptomatic patients.There was no significant change between preoperative BHI with postoperative BHI inthe contralateral side of asymptomatic patients.Conclusion TCD could be used successfully to monitor CVR of the CAS patients before and after CEA by means of BHI.most symptomatic patients showed a low CVR and their CVR increased after CEA.The asymptomatic CS group represented a normal CVR,and their CVR in response to endarterectomy was negligible.PartⅢ.Expression and Meaning of Legumain in the Carotid Atherosclerotic PlaquesObjective To investigate the expression and distribution of legumain through the detection of the protein and mRNA of legumain in CAS plaques.Methods from Jan 2007 to Jan 2009,the 30 atherosclerotic plaque paraffin slices are processed immunohistochemical staining of legumain,and the other 10 unstable atherosclerotic plaques are processed to gather protein and mRNA respectively for western blot and RT-PCR in order to analyze the expression and distribution of legumain.Results Immunohistochemistry staining show that there is legumain expression on normal artery walls symmetrically distributed and mainly situated in the nuclears of ECs,and fibroblast cells.In the plaques,there is a hyperexpression of legumain,mainly situated in the nuclears and cytoplasms of monocytes and macrophages in inflammatory areas.There is a certain liner correlation between the ratios of legumain positive areas to inflammatory areas and the counts of monocytes and macrophages.Western Blot and RT-PCR coincidently show that legumain protein and mRNA express the highest in necrotic areas,low in fibrosis and lipid pool areas,and the lowest in the normal areas.Conclusion Legumain,being a inflammatory factor,may play an important role in the pathological progress and development of CAS.Summary1.Most symptomatic patients show increases of cerebral hemodynamics after CEA.The hemodynamic response of most asymptomatic patients to endarterectomy was negligible.2.TCD could be used successfully to monitor CVR of the CAS patients before and after CEA by means of BHI.most symptomatic patients showed a low CVR and their CVR increased after CEA.The asymptomatic CS group represented a normal CVR,and their CVR in response to endarterectomy was negligible.3.Legumain,being a inflammatory factor,may play an important role in the pathological progress and development of CAS.