Granzyme B PET imaging as a marker of inflammatory bowel disease activity

项目摘要/摘要 炎症性肠病(IBD)是一组发病率较高的炎症性疾病 以及给患者和社会带来的成本。在没有治愈方法的情况下，治疗的方向是控制肠道 使用抗炎和免疫抑制剂的炎症，这已被证明能极大地改善 改善预后，减少并发症。然而，这些疗法的使用应该仅限于那些 由于高成本和严重不良事件的风险，如严重感染，神经学，活动性疾病 疾病、心力衰竭和恶性血液病。内窥镜检查是目前治疗疾病的首选方法 活动度评估与临床结果高度相关。然而，重复使用内窥镜检查是有限的。 由于其侵袭性，难以管理，并限制进入小肠。解剖成像是有帮助的 在活动性疾病的检测中，但在早期反应评估、纤维狭窄的鉴别方面的作用有限 活动性炎症引起的疾病或疾病复发的预测。分子成像目前尚不清楚 IBD的临床价值在于特异性不佳，与临床指标缺乏相关性。一种生物标记物 白细胞活性可能被证明是肠道炎症的理想标记物，并可预测治疗反应。 这种生物标志物可以通过识别亚临床炎症来预防IBD的治疗，从而显著促进IBD的治疗 减少与疾病相关的并发症，减少因治疗无效而产生的费用和副作用。 颗粒酶B(GzmB)是细胞毒性淋巴细胞活性的标志，与疾病活动性密切相关 在IBD。它由激活的淋巴细胞分泌在细胞外基质中，并能产生强烈的炎症反应。 通过处理促炎细胞因子进行反应。我们已经开发了一种基于多肽的PET显像剂， 68Ga-NOTA-GZP，对活性GzmB具有高亲和力和特异性，具有良好的生物分布 肠道发炎。我们已经在初步数据中表明，GZP PET摄取与肠道相关 在小鼠模型中的炎症，并可以区分载体或抗肿瘤坏死因子处理的小鼠。在人体组织样本中 对于活动期克罗恩病，我们的人源化GZP(HGZP)探针对炎症部位进行了强烈染色，而在 而正常受试者和静止期疾病患者则无此反应。因此，GZP PET成像提供了一个独特的洞察 评估活动性炎症和早期反应，目前不能使用其他技术。 我们建议这项研究评估和优化一种新的诊断方法，用于评估疾病活动性和 IBD的早期治疗反应。为了在小鼠模型中验证人类翻译的发现，我们将关联 人组织标本常规组织病理学体外hGZP染色。此外，我们还将 优化一种快速检测小鼠粪便标本中GzmB的护理点诊断方法 在人体样本中进行验证。我们认为对活动性GZMB的非侵入性评估代表了一种新的方法 用于重复评估IBD的疾病活动性和早期治疗反应，并有可能推进护理 并在不久的将来进行研究。

Project Summary/Abstract Inflammatory bowel disease (IBD) is a group of inflammatory disorders associated with significant morbidity and cost to the patients and society. With the absence of a cure, therapy is directed at control of intestinal inflammation using anti-inflammatory and immunosuppressive agents, which have been shown to vastly improve the outcomes and reduce complications. The use of these therapies, however, should only be limited to those with active disease due to high cost and risk of serious adverse events such as serious infections, neurologic disorders, heart failure, and hematologic malignancies. Endoscopy is currently the preferred method of disease activity assessment due to high correlation with clinical outcomes. However, repeated use of endoscopy is limited by its invasiveness, difficult administration, and restricted access to small bowel. Anatomical imaging is helpful in detection of active disease but has limited utility in early response assessment, differentiation of fibrostenotic disease from active inflammation or prediction of disease recurrence. Molecular imaging is currently of unclear clinical value in IBD due to suboptimal specificity and lack of correlation with clinical indices. A biomarker of leukocyte activity may prove to be ideal marker of intestinal inflammation and predictive of response to therapy. Such biomarker can significantly advance IBD management by identifying subclinical inflammation to prevent disease associated complications and reducing the cost and side effects associated with ineffective treatments. Granzyme B (GzmB) is a marker of cytotoxic lymphocyte activity which strongly correlates with disease activity in IBD. It is secreted in the extracellular matrix by activated lymphocytes and can mount a robust inflammatory response by processing proinflammatory cytokines. We have developed a peptide-based PET-imaging agent, 68Ga-NOTA-GZP, with high affinity and specificity for active GzmB and a favorable biodistribution for imaging intestinal inflammation. We have shown in our preliminary data that GZP PET uptake correlates with intestinal inflammation in mouse models and can differentiate vehicle or anti-TNF treated mice. In human tissue specimens of active Crohn’s disease our humanized GZP (hGZP) probe strongly stained the sites of inflammation, while in the normal subjects and quiescent disease did not. Thus, GZP PET imaging offers a unique insight into assessment of active inflammation and early response, not currently possible using other techniques. We propose this study to assess and optimize a novel diagnostic method for assessment of disease activity and early treatment response in IBD. To validate the findings in mouse models for human translation, we will correlate the ex vivo hGZP staining of human tissue specimens with conventional histopathology. Additionally, we will optimize a point of care diagnostic assay for rapid detection of GzmB in stool samples in mouse models and validate in human specimens. We believe non-invasive assessment of active GzmB represents a novel method for repeat assessment of disease activity and early treatment response in IBD with potential to advance care and research in the near future.