UHPLC–MS/MS Identifies Serum Biomarkers for Diagnosing Cystic Echinococcosis in Sheep

A recent study used ultrahigh-performance liquid chromatography (UHPLC) separation with tandem mass spectrometry (MS/MS) detection to explore the metabolic alterations underlying the disease’s progression in sheep infected with cystic echinococcosis (CE). The researchers sought to identify diagnostic biomarkers to analyze serum samples from both sheep infectedwith Echinococcus granulosus and a control group. The goal, the research team wrote, is to increase the understanding of CE at the metabolic level and provide reliable biomarkers for early diagnosis of the disease in clinical settings. A paper based on this study was published in Parasites & Vectors (1).

CE is a parasitic disease caused by infection with the larvae of tapeworms belonging to Echinococcus granulosus. It is a significant health concern, with two primary types of pathogens contributing to its prevalence: CE caused by E. granulosus sensu lato and alveolar echinococcosis attributed to Echinococcus multilocularis, with the former specifically standing out as the predominant pathogen responsible for hydatid disease worldwide (2-5). CE is widespread and prevalent in many regions, especially affecting rural environments where humans and animals closely coexist in Africa, the Middle East, Mediterranean Europe, Central Asia, South America, and western China (6).

Female sheep (2–4 months old) maintained on forage grass and tap water were artificially infected orally with 1000 E. granulosus eggs. After 180 days, the animals were euthanized, and positive serum was collected. Autopsies were then performed, with the livers and lungs removed for examination of the cystic condition. Serum samples from a total of two groups of sheep (six samples from diseased sheep, and another six from healthy sheep during the same period selected as a healthy control group) were selected for the experiment, with six biological replicates in each group. Using UHPLC–MS/MS technology, the researchers identified numerous specific metabolites in the serum of the sheep contaminated with CE, including 1,7-dihydroxyxanthone, 2-methylbutyrylglycine, 3,3-dimethylglutaric acid, 5,12-dihydroxy-6,8,10,14,17-eicosapentaenoic acid, 9-hydroperoxy-10E,12Z,15Z-octadecatrienoic acid, and trimethylamine N-oxide 6, providing numerous diagnostic biomarkers in clinical practice (1).

The results of the analysis revealed changes closely related to amino acid metabolism and fatty acid metabolism pathways and that the energy metabolism of the host may interfere with the process of infection, which may provide a reference for understanding the biological mechanisms and diagnostic biomarkers involved in the process of early CE infection. In addition, changes in the serum levels of glycine, arginine, l-isoleucine, and l-valine in sheep in the CE group may be attributed to liver damage caused by CE lesions parasitizing the liver, resulting in disruption of the metabolic balance of amino acids in the body, which led to the researchers concluding that the metabolites important for CE were valine, leucine, isoleucine, glycine, and fenugreek (1).

The authors said that further research is warranted to elucidate the molecular mechanisms responsible for the effect of lipid and amino acid metabolites on the pathogenicity of Echinococcus. In addition, the small sample size of the current study is a potential limitation, and the results should be validated with a larger sample and more diverse host groups. Finally, additional possible steps for CE lesions in the host should be considered in future experiments (1).

Sheep in pasture. © Baronb - stock.adobe.com

References

1. Wu, X. X.; Ban, W. L.; Wu, L. J.; Qi, W. J.; Borhani, M.; He, X.Y.; Liu, X. L.; Liu, M. Y.; Ding, J. Identification of Serum Biomarkers for Cystic Echinococcosis in Sheep Through Untargeted Metabolomic Analysis Using LC-MS/MS Technology. Parasit. Vectors 2024, 17 (1), 547. DOI: 10.1186/s13071-024-06599-6

2. Borhani, M.; Mohammadi, M. A.; Entezami, M.; Baneshi, M. R.; Nasibi, S.; Prada, J. M.; Fasihi Harandi, M. Reinfection of Farm Dogs Following Praziquantel Treatment in an Endemic Region of Cystic Echinococcosis in Southeastern Iran. PLoS Negl. Trop Dis. 2024, 18 (3), e0011939. DOI: 10.1371/journal.pntd.0011939

3. Casulli, A.; Abela-Ridder, B.; Petrone, D.; Fabiani, M.; Bobić, B.; Carmena, D.; Šoba, B. et al. Unveiling the Incidences and Trends of the Neglected Zoonosis Cystic Echinococcosis in Europe: A Systematic Review from the MEmE Project. Lancet Infect. Dis. 2023, 23(3), e95-e107. DOI: 10.1016/S1473-3099(22)00638-7

4. Borhani, M.; Fathi, S.; Darabi, E.; Jalousian, F.;Simsek, S.; Ahmed, H.; Kesik, H. K.;Hosseini, S. H.; Romig, T; Harandi, M. F.; Mobedi I. Echinococcoses in Iran, Turkey, and Pakistan: Old Diseases in the New Millennium. Clin. Microbiol Rev. 2021, 34 (3), e0029020. DOI: 10.1128/CMR.00290-20

5. Cooper, C.; Clode, P. L.; Peacock, C.; Thompson R. C. Host-Parasite Relationships and Life Histories of Trypanosomes in Australia. Adv. Parasitol. 2017, 97, 47-109. DOI: 10.1016/bs.apar.2016.06.001

6. Torgerson, P. R.; Robertson, L. J.; Enemark, H. L.; Foehr, J.; van der Giessen, J. W. B.;Kapel, C. M. O.; Klun, I.; Trevisan, C. Source Attribution of Human Echinococcosis: A Systematic Review and Meta-Analysis. PLoS Negl. Trop Dis. 2020, 14 (6), e0008382. DOI: 10.1371/journal.pntd.0008382