London, United Kingdom 2013 6 Experimental studies Ephrin-B2 regulates angiogenesis in the ipsilateral thalamus after focal cortical infarction S.H. Xing1, N.N. Pan2, J. Zhang3, J.J. Li4, C. Dang5, G. Liu6, L. Chen7, Y.H. Fan8, J.S. Zeng9 Department of Neurology and Stroke Center, The First Affiliated Hospital, Sun Yat-Sen Uni-versity, Guangzhou, CHINA1, , , CHINA2, Department of Neurology and Stroke Center, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, CHINA3, Department of Neurology and Stroke Center, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, CHINA4, De-partment of Neurology and Stroke Center, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, CHINA5, Department of Neurology and Stroke Center, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 6, Department of Neurology and Stroke Center, The First Affil-iated Hospital, Sun Yat-Sen University, Guangzhou, CHINA7, Department of Neurology and Stroke Center, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, CHINA8, Department of Neurology and Stroke Center, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, CHINA9 Background: Focal cerebral infarction leads to secondary thalamic damage which is accompanied by angiogenesis. Ephrin-B2 controls angiogenesis during embryogenesis and tumorgenesis. The present study was designed to investigate whether Ephrin-B2 regulated angiogenesis in thalamus after cerebral infarction. Methods: Focal cerebral cortical infarction was induced by middle cere-bral artery occlusion (MCAO). Lentivirus-mediated Ephrin-B2 shRNA (Efnb2-shRNA) was used to silence Ephrin-B2 expression in thalamus. Clustered EphB2-Fc was intraventrically adminis-tered to enhance Ephrin-B2 reverse signal. DAPT was used to inhibit Notch1 cleavage. Bromode-oxyuridine (BrdU) was given to label cell proliferation. Nissl staining and immunoreactivities of Ephrin-B2, MAP-2, GFAP, BrdU, vWF, Laminin, cleaved Notch1 and amyloid-β (Aβ) in thalamus were examined at 7 days after MCAO respectively. Results: In ipsilateral thalamus, neuronal loss (characterized by Nissl and MAP-2 staining) and GFAP positive astroglial reaction was obviously observed at 7 days after MCAO compared with sham control (all p<0.05). Concomitantly, the num-ber of BrdU+/Laminin+ cells and density of immunoreactive vessel were markedly increased when compared to sham control (both p<0.05). Ephrin-B2 level was predominantly elevated in vWF+ vessels in ipsilateral thalamus after MCAO compared to sham control (p<0.05). Knockdown of Efnb2 markedly decreased Ephrin-B2 expression as well as BrdU+/Laminin+ cells and immunore-active vessel density in ipsilateral thalamus when compared to controls (both p<0.05). In contrast, EphB2-Fc enhanced BrdU+/Laminin+ cells and immunoreactive vessel density compared with IgG-Fc group (both p<0.05). Additionally, DAPT significantly reduced Notch1 cleavage and Ephrin-B2 expression in ipsilateral thalamus when compared to vehicle group (all p<0.05). Conclusion: The findings suggest that Notch1/Ephrin-B2 may regulate angiogenesis in ipsilateral thalamus following focal cerebral infarction. E-Poster Session Red Cerebrovasc Dis 2013; 35 (suppl 3)1-854 249 5 Experimental studies PLATELET RICH CLOTS ARE RESISTANT TO LYSIS BY THROMBOLYTIC THERAPY IN A RAT MODEL OF EMBOLIC STROKE A.J. Tomkins1, N. Schleicher2, M. Nedelmann3, N.J. Spratt4 School of Biomedical Sciences & Pharmacy, University of Newcastle, Newcastle, AUSTRA-LIA1, Department of Neurology, Justus Liebig University, Giessen, GERMANY2, Department of Neurology, Justus Liebig University, Giessen, GERMANY3, School of Biomedical Sciences & Pharmacy, University of Newcastle, Newcastle, AUSTRALIA4 Early recanalization of occluded vessels in stroke is associated with improved outcome but recom-binant tissue plasminogen activator (rtPA) treatment benefits less than half of patients treated. New methods are emerging to enhance thrombolysis with rtPA e.g. microbubble-enhanced sonothrombol-ysis (ultrasound). Models of embolic stroke are most appropriate for preclinical thrombolytic testing due to the presence of thrombi, yet a standard model is lacking due to high variability of outcomes. We aimed to design an embolic model with stable occlusion of the middle cerebral artery (MCA) and to test the efficacy of microbubble-enhanced sonothrombolysis. Spontaneously hypertensive rats (SHR) underwent MCA embolism with site-specific delivery to the MCA origin of preformed platelet-rich clots (PRC). A preliminary study (n = 7) used continuous la-ser Doppler (LD) monitoring for 4 h post-embolism and sacrifice at 24 h to investigate spontaneous recanalization rates and infarct volumes. Effect of thrombolysis was then studied in 3 groups: rtPA (10 mg/kg), rtPA + ultrasound + BR38 microbubbles (Bracco Research, Geneva) and saline control (n = 10 per group). Treatment onset was 60 min post-embolism and lasting 60 min. Intermittent LD recordings were made during the protocol. Sacrifice was post-treatment and brains were perfused to determine presence and location of remaining clots. MCAo with PRC resulted in large infarcts in all cases (47.26 ± 7.97% of ipsilateral hemisphere). In the preliminary study, LD reperfusion occurred in 2/7 animals (40.08 and 69.83 min post-embolism) with 1 mortality due to large infarction. In the treatment study, no reperfusion was observed by LD, and clot was identified in the major cerebral vasculature at post mortem in all animals. Site-specific delivery of PRC produce large infarction in the SHR however clots are highly stable and resistant to both spontaneous lysis and thrombolytic treatment making this model unsuitable to study new thrombolytics.
Karger_ESC London_2013
To see the actual publication please follow the link above