Department of Radiology, Chinese PLA General Hospital, No. 28 Fuxing Road, Beijing, 100853, P. R. China.
Key Laboratory of Colloid, Interface and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, Bei Yi Jie 2, Zhong Guan Cun, Beijing, 100190, P. R. China.
Small. 2018 Jun;14(23):e1800573. doi: 10.1002/smll.201800573. Epub 2018 Apr 17.
Ischemic stroke is one of the major leading causes for long-term disability and mortality. Collateral vessels provide an alternative pathway to protect the brain against ischemic injury after arterial occlusion. Aiming at visualizing the collaterals occurring during acute ischemic stroke, an integrin α β -specific Fe O -Arg-Gly-Asp (RGD) nanoprobe is prepared for magnetic resonance imaging (MRI) of the collaterals. Rat models are constructed by occluding the middle cerebral artery for imaging studies of cerebral ischemia and ischemia-reperfusion on 7.0 Tesla MRI using susceptibility-weighted imaging sequence. To show the binding specificity to the collaterals, the imaging results acquired with the Fe O -RGD nanoprobe and the Fe O mother nanoparticles, respectively, are carefully compared. In addition, an RGD blocking experiment is also carried out to support the excellent binding specificity of the Fe O -RGD nanoprobe. Following the above experiments, cerebral ischemia-reperfusion studies show the collateral dynamics upon reperfusion, which is very important for the prognosis of various revascularization therapies in the clinic. The current study has, for the first time, enabled the direct observation of collaterals in a quasi-real time fashion and further disclosed that the antegrade flow upon reperfusion dominates the blood supply of primary ischemic tissue during the early stage of infarction, which is significantly meaningful for clinical treatment of stroke.
缺血性中风是导致长期残疾和死亡的主要原因之一。侧支血管为动脉闭塞后保护大脑免受缺血性损伤提供了一种替代途径。为了可视化急性缺血性中风期间发生的侧支，制备了整合素 α β 特异性 FeO-Arg-Gly-Asp（RGD）纳米探针，用于磁共振成像（MRI）对侧支的成像研究。通过阻塞大脑中动脉构建大鼠模型，在 7.0T MRI 上使用磁敏感加权成像序列进行脑缺血和缺血再灌注的成像研究。为了显示对侧支的结合特异性，仔细比较了分别使用 FeO-RGD 纳米探针和 FeO 母纳米颗粒获得的成像结果。此外，还进行了 RGD 阻断实验，以支持 FeO-RGD 纳米探针的优异结合特异性。在进行上述实验之后，缺血再灌注研究显示了再灌注时侧支的动力学，这对于临床各种血管再通治疗的预后非常重要。本研究首次能够以准实时方式直接观察侧支，并进一步揭示了再灌注时的前向血流在梗死早期主导原发性缺血组织的血液供应，这对中风的临床治疗具有重要意义。
