J&J Global Public Health, Janssen R&D, Beerse, Belgium.
Discovery Sciences, Janssen R&D, Beerse, Belgium.
PLoS Negl Trop Dis. 2021 Nov 29;15(11):e0009999. doi: 10.1371/journal.pntd.0009999. eCollection 2021 Nov.
The neglected tropical disease onchocerciasis, or river blindness, is caused by infection with the filarial nematode Onchocerca volvulus. Current estimates indicate that 17 million people are infected worldwide, the majority of them living in Africa. Today there are no non-invasive tests available that can detect ongoing infection, and that can be used for effective monitoring of elimination programs. In addition, to enable pharmacodynamic studies with novel macrofilaricide drug candidates, surrogate endpoints and efficacy biomarkers are needed but are non-existent. We describe the use of a multimodal untargeted mass spectrometry-based approach (metabolomics and lipidomics) to identify onchocerciasis-associated metabolites in urine and plasma, and of specific lipid features in plasma of infected individuals (O. volvulus infected cases: 68 individuals with palpable nodules; lymphatic filariasis cases: 8 individuals; non-endemic controls: 20 individuals). This work resulted in the identification of elevated concentrations of the plasma metabolites inosine and hypoxanthine as biomarkers for filarial infection, and of the urine metabolite cis-cinnamoylglycine (CCG) as biomarker for O. volvulus. During the targeted validation study, metabolite-specific cutoffs were determined (inosine: 34.2 ng/ml; hypoxanthine: 1380 ng/ml; CCG: 29.7 ng/ml) and sensitivity and specificity profiles were established. Subsequent evaluation of these biomarkers in a non-endemic population from a different geographical region invalidated the urine metabolite CCG as biomarker for O. volvulus. The plasma metabolites inosine and hypoxanthine were confirmed as biomarkers for filarial infection. With the availability of targeted LC-MS procedures, the full potential of these 2 biomarkers in macrofilaricide clinical trials, MDA efficacy surveys, and epidemiological transmission studies can be investigated.
被忽视的热带病盘尾丝虫病,也称河盲症,是由盘尾丝虫属的线虫感染引起的。目前的估计表明,全世界有 1700 万人感染,其中大多数生活在非洲。目前没有非侵入性的测试可以检测到正在进行的感染,也不能用于有效监测消除计划。此外,为了使新型杀微丝蚴药物候选物进行药效学研究,需要有替代终点和疗效生物标志物,但目前尚不存在。我们描述了使用多模式非靶向质谱(代谢组学和脂质组学)来鉴定尿液和血浆中与盘尾丝虫病相关的代谢物,以及感染个体血浆中的特定脂质特征(盘尾丝虫感染病例:68 名可触及结节的个体;淋巴丝虫病病例:8 名;非流行区对照:20 名)。这项工作确定了血浆代谢物肌苷和次黄嘌呤的浓度升高作为丝虫感染的生物标志物,以及尿液代谢物顺肉桂酰基甘氨酸(CCG)作为盘尾丝虫的生物标志物。在靶向验证研究中,确定了代谢物特异性的截断值(肌苷:34.2ng/ml;次黄嘌呤:1380ng/ml;CCG:29.7ng/ml),并建立了敏感性和特异性特征。随后在来自不同地理区域的非流行区人群中评估这些生物标志物,否定了尿液代谢物 CCG 作为盘尾丝虫的生物标志物。血浆代谢物肌苷和次黄嘌呤被确认为丝虫感染的生物标志物。随着靶向 LC-MS 程序的可用性,可以进一步研究这 2 种生物标志物在杀微丝蚴药物临床试验、MDA 疗效调查和流行病学传播研究中的全部潜力。