Differentiation of Glioma from Radiation Injury Using Cellular MRI

描述（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，目前的成像方式无法最终区分复发或残留肿瘤与放射性坏死或坏死组织。及早发现复发肿瘤是正确治疗和随访的关键。最近树突状细胞疫苗和细胞毒性t淋巴细胞（CTL）正在考虑治疗复发性胶质瘤。在动物模型和临床试验的早期阶段，CTL已被证明在胶质瘤中积累。通过追踪CTL的迁移和归巢，有可能区分复发性胶质瘤和放射性坏死。最近，使用两种fda批准的制剂，我们形成了阿魏氧化物-硫酸鱼精蛋白复合物，并标记了任何一种哺乳动物细胞。为了检验标记细胞是否可以作为细胞探针来检测和区分生理和/或病理状况，我们选择了胶质瘤和辐射损伤模型。据推测，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模式的积累和纳入标记注入的ctl，从而允许区分复发性胶质瘤和辐射损伤。本研究的目的将通过在荷瘤或对照裸鼠身上制作胶质瘤和辐射损伤模型来实现。裸鼠将被用来植入人类U-251胶质瘤细胞系。在这些大鼠中，我们将测试U-251细胞裂解液脉冲树突状细胞体外产生的ctl是否能够识别植入的人类胶质瘤并将其与辐射损伤区分开来。利用铁铁-硫酸鱼精蛋白复合物对体外生成的ctl进行磁性标记，并将标记的细胞注射到处于疾病不同阶段的大鼠的尾静脉中。由于细胞内氧化铁的易感性作用，这些被标记的细胞一旦被纳入肿瘤或损伤区域，就可以在体内和离体MRI上被检测到为低信号强度区域。在不同时间点注射标记细胞后，通过7特斯拉MRI系统获得肿瘤和辐射损伤区域的序列MRI。MRI的结果将与组织学和ctl的免疫组织化学检测相关联。结果还将在各组动物之间进行比较。早期发现复发或转移性神经胶质瘤以及早期从放射性坏死中区分神经胶质瘤将有助于临床医生治疗这种破坏性的神经恶性肿瘤。通过无创成像技术早期发现和鉴别复发性胶质瘤与放射性损伤/坏死是正确治疗这种毁灭性恶性疾病的必要条件。如果这些研究顺利完成，结果很容易转化为临床试验，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分离的造血干细胞分化而来[PBMC]）可以用来产生细胞毒性t淋巴细胞（CTL），靶向肿瘤细胞，用于检测和分化肿瘤与辐射损伤/坏死。基因工程CTL也可以使用。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以及靶区。

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).