Optimizing blood PCR as test of cure in Chagas disease

优化血液 PCR 作为恰加斯病的治愈测试

• 批准号: 10590740
• 负责人: Rick L Tarleton
• 金额: $ 7.55万
• 依托单位: UNIVERSITY OF GEORGIA
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-03-11 至 2024-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10590740
• 关键词: Aftercare; Aliquot; Animals; Biological Assay; Blood; Blood specimen; Chagas Disease; Clinical; Clinical Trials; Collection; Communicable Diseases; DNA; DNA purification; Data; Detection; Development; Diagnosis; Diagnostic; Discrimination; Disease; Enrollment; Frequencies; Future; Goals; Hemorrhage; Human; Immune response; Individual; Infection; Latin America; Macaca; Macaca mulatta; Measurement; Measures; Medicine; Methods; Muscle; Outcome; Outcome Study; Parasites; Participant; Pattern; Pharmaceutical Preparations; Ploidies; Population; Protocols documentation; Research; Sampling; Serology test; Specimen; Techniques; Testing; Therapeutic; Time; Treatment Efficacy; Treatment outcome; Trypanosoma cruzi; United States; Variant; Work; candidate identification; candidate selection; chronic infection; comparative; cost; curative treatments; drug candidate; efficacy evaluation; experimental study; improved; nonhuman primate; novel therapeutics; prevent; research clinical testing; screening; seropositive; success; tool; transmission process

Abstract Infection with the protozoan parasite Trypanosoma cruzi is generally controlled but often not eliminated by host immune responses. In humans and many other hosts, this persistent infection ultimately results in muscle tissue damage known as Chagas disease. Although several partially effective drugs exist to treat the infection, it is estimated that only ~1% of infected subjects receive treatment. The major impediment to the wider use of current drugs, the development of better therapeutics in Chagas disease, and the identification of those who would benefit from treatment and the success of treatment in those individuals, is the absence of reliable methods to definitively determine the presence or absence of infection. Diagnosis of possible infection is generally achieved using a combination of serological tests, which are reliable for detecting prior exposure but provide limited information on whether the infection is active. The goal of this project is to validate and improve PCR-based tests of cure for T. cruzi infection. The primary application of the results of this study will be to the more definitive evaluation of clinical trial outcomes. Current PCR-detection protocols for diagnosis of T. cruzi infection generally use a very limited (sometimes only one) blood sample and assay a single aliquot from that sample. However, subjects in trials of anti-T. cruzi drugs are generally bled multiple (4-6) times post-treatment and 1-3 aliquots are submitted to PCR, usually with variable results between bleeds and aliquots. The hypothesis underlying the proposed work is that definitive detection of infection via PCR of parasite DNA in blood can be achieved by increasing the sampling of blood, both the number of blood samples taken and the aliquots of that blood that are evaluated by PCR. This hypothesis will be tested in a group of naturally infected rhesus macaques who will be repeatedly sampled over both an extended time frame (1 year) and a more limited period (1 month) with up to 200 aliquots of DNA screened by PCR at each bleed point. Parallel studies using parasite- or parasite-DNA-spiked blood we allow interpretation of the blood parasite levels in the infected animals, and its variation, over months or years. The ultimate outcome of these studies is expected to be a dependable pre-enrollment protocol for participant selection for clinical drug trials and definitive tests at the conclusion of such trials that unequivocally measure treatment efficacy. Such tools will assure that future clinical trials of candidate anti-T. cruzi drugs will provide conclusive results.

摘要 感染原生动物克氏锥虫通常可以控制，但通常不能通过宿主免疫消除。 回应。在人类和许多其他宿主中，这种持续感染最终会导致已知的肌肉组织损伤。 作为恰加斯病。尽管有几种部分有效的药物可以治疗这种感染，但据估计，只有~1%的 受感染的患者接受治疗。目前药物更广泛使用的主要障碍是开发更好的 Chagas病的治疗，以及那些将从治疗中受益的人的确定和成功的 对这些人的治疗，是缺乏可靠的方法来确定是否存在 感染。诊断可能的感染通常是通过结合可靠的血清学试验来实现的。 用于检测以前的接触情况，但提供的关于感染是否活跃的信息有限。这个项目的目标是 目的验证和改进基于聚合酶链式反应的克氏毛滴虫治疗试验。本研究成果的初步应用 将对临床试验结果进行更明确的评估。目前用于诊断弓形虫的PCR检测方法 克鲁兹病毒感染通常使用非常有限的(有时只有一个)血液样本，并从中检测一份等量 样本。然而，抗T.克鲁兹类药物一般在治疗后出血多次(4-6次)，1-3次 等量样本被提交给聚合酶链式反应，通常在出血和等分结果之间有不同的结果。其背后的假说是 建议的工作是通过对血液中寄生虫DNA的聚合酶链式反应来实现对感染的明确检测，方法是增加 血液样本，包括采集的血液样本的数量和通过聚合酶链式反应进行评估的血液等量。 这一假设将在一组自然感染的恒河猴身上进行验证，这些恒河猴将被反复抽样 延长的时间范围(1年)和更有限的时间(1个月)，通过以下方式筛选最多200等分的DNA 在每个出血点进行聚合酶链式反应。使用寄生虫-或寄生虫-DNA添加的血液进行的平行研究，我们可以解释 受感染动物的血液寄生虫水平及其在几个月或几年内的变化。这些事件的最终结果是 预计研究将成为临床药物试验参与者选择的可靠预登记方案，并 在这类试验结束时明确地衡量治疗效果的最终测试。这些工具将确保 未来的候选抗T。克鲁兹药物将提供确凿的结果。