Differentiation of Glioma from Radiation Injury Using Cellular MRI

描述（由申请人提供）：尽管有广泛的治疗策略和研究，多形性胶质母细胞瘤的预后仍然很差。主要原因是在常规检查或手术中无法描绘肿瘤的边缘。此外，目前的成像模式不能最终区分复发或遗留的肿瘤与放射性坏死或坏死组织。对于适当的管理和随访，最重要的是尽早发现复发肿瘤。最近，树突状细胞为基础的疫苗接种和细胞毒性T淋巴细胞（CTL）被认为是治疗复发性胶质瘤。在动物模型中以及在临床试验的早期阶段中，已经显示CTL在胶质瘤中积累。通过跟踪CTL的迁移和归巢，有可能将复发性胶质瘤与放射性坏死区分开来。最近，使用两种FDA批准的试剂，我们形成了ferumoxides-硫酸鱼精蛋白复合物，并标记任何种类的哺乳动物细胞。为了检查标记的细胞是否可以用作细胞探针来检测和区分生理和/或病理条件，我们选择了胶质瘤和放射损伤模型。据推测，在体内磁共振成像（MRI）跟踪磁标记的CTL将使我们能够识别不同的模式的积累和标记的注射的CTL的掺入，从而允许复发性胶质瘤和放射损伤之间的分化。本研究的目的是通过在荷瘤裸鼠和对照裸鼠中建立胶质瘤模型和放射损伤模型来实现。将使用裸大鼠植入人U-251胶质瘤细胞系。在这些大鼠中，我们将测试由U-251细胞裂解物脉冲的树突状细胞在体外产生的CTL是否可以识别植入的人脑胶质瘤并将其与辐射损伤区分开来。体外产生的CTL将使用菲立磁-硫酸鱼精蛋白复合物进行磁性标记，标记的细胞将在其疾病过程的不同阶段注射到大鼠的尾静脉中。这些标记的细胞，一旦掺入肿瘤或损伤区域，由于细胞内氧化铁的易感性效应，可以在体内和离体MRI上检测到低信号强度区域。在不同时间点注射标记细胞后，将通过7特斯拉MRI系统获得肿瘤和辐射损伤区域的系列MRI。MRI表现与组织学、CTL免疫组化检测结果有相关性。还将比较所有组动物的结果。早期发现胶质瘤的复发或转移，以及早期鉴别胶质瘤与放射性坏死，将有助于临床医生治疗这种毁灭性的神经系统恶性肿瘤。早期发现和鉴别复发胶质瘤放射损伤/坏死的非侵入性成像技术是必要的，适当的管理，这种毁灭性的恶性疾病。如果这些研究成功完成，结果可以很容易地转化为临床试验，其中患者自身的树突状细胞（从自体单核细胞和/或从外周血单核细胞[PBMC]分离的造血干细胞分化而来）可以用于产生细胞毒性T淋巴细胞（CTL），以靶向肿瘤细胞，用于检测和区分肿瘤与辐射损伤/坏死。也可以使用遗传工程改造的CTL。这种磁标记技术还将帮助研究人员通过磁共振成像（MRI）跟踪体内注射的CTL以及靶向区域。

DESCRIPTION (provided by applicant): Despite extensive treatment strategies and investigations, the prognosis of glioblastoma multiforme is still poor. The main reason is the inability to delineate the margin of the tumor during routine investigations or during surgery. Moreover, current imaging modalities fail to differentiate, conclusively, the recurrent or left over tumor from radiation necrosis or necrotic tissues. For proper management and follow up it is utmost important to detect recurrent tumor as early as possible. Recently dendritic cell based vaccination and cytotoxic T-lymphocytes (CTL) are being considered for the treatment of recurrent glioma. In the animal models as well as in the early phases of clinical trials, CTL has been shown to accumulate in the glioma. By tracking the migration and homing of CTL it may be possible to differentiate recurrent glioma from radiation necrosis. Recently, using two FDA-approved agents, we formed ferumoxides-protamine sulfate complex and labeled any kind of mammalian cells. To examine whether labeled cells can be used as cellular probes to detect and differentiate physiological and/or pathological conditions, we have selected glioma and radiation injury models. It is hypothesized that in vivo magnetic resonance imaging (MRI) tracking of magnetically labeled CTLs will enable us to identify different patterns of accumulation and incorporation of labeled injected CTLs, thus allowing for differentiation between recurrent glioma and radiation injury. The goals of this study will be achieved by making glioma as well as radiation injury models in tumor bearing or control nude rats. Nude rats will be used to implant human U-251 glioma cell lines. In these rats we will test whether CTLs produced in vitro by U-251 cell lysate-pulsed dendritic cells can recognize the implanted human glioma and differentiate it from radiation injury. CTLs produced in vitro will be magnetically labeled using feridex- protamine sulfate complexes and the labeled cells will be injected into tail vein of the rats at different stages of their disease processes. These labeled cells, once incorporated into the tumors or areas of injury, can be detected as low signal intensity areas on in vivo and ex vivo MRI because of the susceptibility effects of iron oxides inside the cells. Serial MRI of tumors and radiation injured areas after injecting labeled cells at different time points will be obtained by a 7 tesla MRI system. The findings of MRI will be correlated with histology, and immuonohistochemical detection of CTLs. The results will also be compared among the animals of all groups. Early detection of recurrent or metastatic glioma as well as early differentiation of glioma from radiation necrosis will help clinician to tackle this devastating neurological malignant tumor. Early detection and differentiation of recurrent glioma from radiation injury/necrosis by noninvasive imaging technique is essential for the proper management of this devastating malignant disease. If these studies are successfully completed, the results can easily be translated into a clinical trial, where patients' own dendritic cells (differentiated from autologous monocytes and/or hematopoietic stem cells separated from peripheral blood mononuclear cells [PBMC]), can be used to produce cytotoxic T-lymphocytes (CTL) to target tumor cells for detection and differentiation of tumor from radiation injury/necrosis. Genetically engineered CTL can also be used. This magnetic labeling technique will also help investigators to track the injected CTL in the body as well as in the targeted areas by magnetic resonance imaging (MRI).