Arabinofuranose‐derived positron‐emission tomography radiotracers for detection of pathogenic microorganisms
作者:Mausam Kalita、Matthew F.L. Parker、Justin M. Luu、Megan N. Stewart、Joseph E. Blecha、Henry F. VanBrocklin、Michael J. Evans、Robert R. Flavell、Oren S. Rosenberg、Michael A. Ohliger、David M. Wilson
DOI:10.1002/jlcr.3835
日期:2020.5.15
PURPOSE: Detection of bacteria-specific metabolism via positron emission tomography (PET) is an emerging strategy to image human pathogens, with dramatic implications for clinical practice. In silico and in vitro screening tools have recently been applied to this problem, with several monosaccharides including l-arabinose showing rapid accumulation in Escherichia coli and other organisms. Our goal for this study was to evaluate several synthetically viable arabinofuranose-derived 18F analogs for their incorporation into pathogenic bacteria. PROCEDURES: We synthesized four radiolabeled arabinofuranose-derived sugars: 2-deoxy-2-[18F]fluoro-arabinofuranoses (d-2-18F-AF and l-2-18F-AF) and 5-deoxy-5-[18F]fluoro-arabinofuranoses (d-5-18F-AF and l-5-18F-AF). The arabinofuranoses were synthesized from 18F- via triflated, peracetylated precursors analogous to the most common radiosynthesis of 2-deoxy-2-[18F]fluoro-d-glucose ([18F]FDG). These radiotracers were screened for their uptake into E. coli and Staphylococcus aureus. Subsequently, the sensitivity of d-2-18F-AF and l-2-18F-AF to key human pathogens was investigated in vitro. RESULTS: All 18F radiotracer targets were synthesized in high radiochemical purity. In the screening study, d-2-18F-AF and l-2-18F-AF showed greater accumulation in E. coli than in S. aureus. When evaluated in a panel of pathologic microorganisms, both d-2-18F-AF and l-2-18F-AF demonstrated sensitivity to most gram-positive and gram-negative bacteria. CONCLUSIONS: Arabinofuranose-derived 18F PET radiotracers can be synthesized with high radiochemical purity. Our study showed absence of bacterial accumulation for 5-substitued analogs, a finding that may have mechanistic implications for related tracers. Both d-2-18F-AF and l-2-18F-AF showed sensitivity to most gram-negative and gram-positive organisms. Future in vivo studies will evaluate the diagnostic accuracy of these radiotracers in animal models of infection.
目的:通过正电子发射断层扫描(PET)检测细菌特异性代谢是一种新兴的人类病原体成像策略,对临床实践具有重大意义。硅学和体外筛选工具最近已被应用于这一问题,包括 l-阿拉伯糖在内的几种单糖在大肠杆菌和其他生物体内显示出快速积累。我们这项研究的目标是评估几种合成可行的阿拉伯呋喃糖衍生 18F 类似物,以确定它们是否能被病原菌吸收。过程:我们合成了四种放射性标记的阿拉伯呋喃糖衍生糖:2-脱氧-2-[18F]氟阿拉伯呋喃糖(d-2-18F-AF 和 l-2-18F-AF)和 5-脱氧-5-[18F]氟阿拉伯呋喃糖(d-5-18F-AF 和 l-5-18F-AF)。阿拉伯呋喃糖是由 18F- 通过三氯化、过乙酰化前体合成的,类似于最常见的 2-脱氧-2-[18F]氟-d-葡萄糖([18F]FDG)的放射合成。对这些放射性racer进行了筛选,以确定它们是否能被大肠杆菌和金黄色葡萄球菌吸收。随后,在体外研究了 d-2-18F-AF 和 l-2-18F-AF 对主要人类病原体的敏感性。结果:所有 18F 放射性示踪剂靶标都以高放射化学纯度合成。在筛选研究中,d-2-18F-AF 和 l-2-18F-AF 在大肠杆菌中的蓄积量大于在金黄色葡萄球菌中的蓄积量。在一组病理微生物中进行评估时,d-2-18F-AF 和 l-2-18F-AF 对大多数革兰氏阳性和革兰氏阴性细菌都表现出敏感性。结论:阿拉伯呋喃糖衍生的 18F PET 放射性标记物可以合成,且放射化学纯度很高。我们的研究表明,5-取代类似物没有细菌蓄积,这一发现可能对相关示踪剂具有机理意义。d-2-18F-AF 和 l-2-18F-AF 对大多数革兰氏阴性和革兰氏阳性菌都很敏感。未来的体内研究将评估这些放射性核素在动物感染模型中的诊断准确性。