Discovery of Infection Associated Metabolic Markers in Human African Trypanosomiasis

Abstract

Human African trypanosomiasis (HAT) remains a major neglected tropical disease in Sub-Saharan Africa. As clinical symptoms are usually non-specific, new diagnostic and prognostic markers are urgently needed to enhance the number of identified cases and optimise treatment. This is particularly important for disease caused by Trypanosoma brucei rhodesiense, where indirect immunodiagnostic approaches have to date been unsuccessful. We have conducted global metabolic profiling of plasma from T.b.rhodesiense HAT patients and endemic controls, using 1H nuclear magnetic resonance (NMR) spectroscopy and ultra-performance liquid chromatography, coupled with mass spectrometry (UPLC-MS) and identified differences in the lipid, amino acid and metabolite profiles. Altogether 16 significantly disease discriminatory metabolite markers were found using NMR, and a further 37 lipid markers via UPLC-MS. These included significantly higher levels of phenylalanine, formate, creatinine, N-acetylated glycoprotein and triglycerides in patients relative to controls. HAT patients also displayed lower concentrations of histidine, sphingomyelins, lysophosphatidylcholines, and several polyunsaturated phosphatidylcholines. While the disease metabolite profile was partially consistent with previous data published in experimental rodent infection, we also found unique lipid and amino acid profile markers highlighting subtle but important differences between the host response to trypanosome infections between animal models and natural human infections. Our results demonstrate the potential of metabolic profiling in the identification of novel diagnostic biomarkers and the elucidation of pathogenetic mechanisms in this disease.

Metabolomics Identifies Multiple Candidate Biomarkers to Diagnose and Stage Human African Trypanosomiasis

“…b . rhodesiense infection [25] where changes in amino acid and lipid metabolism compared to uninfected control patients were reported, although robust markers that would be suitable for diagnostics were not proposed [25]. We were able to find changes in the levels of ornithine and aminododecanoic acid in blood that were predictive of both the presence of disease and disease stage.…”

“…These metabolites were not detected in the study by Lamour et al . [25], and so it would be interesting to test samples from T . b .…”

“…High resolution mass spectrometry can be used to identify a wide range of metabolic species in a technique known as metabolomics [24]. Differences in the abundance of these small (<1200 Da) metabolites in the biofluids of infected individuals may be used to discriminate between different disease states with the aim of developing new diagnostic tools [25] and a recent study made the first tentative investigations into possible biomarkers in HAT patients. This study was limited, however, due to a lack of patient stratification, and was only done in T .…”

Sleeping Sickness in the ‘Omics Era

“…A few studies adopting metabolomics as a biomarker discovery approach have been published as well. Global metabolomics profiling of plasma samples showed alterations between T. b. rhodesiense patients and healthy controls . In particular, strong alterations in lipid profiles were associated with the infection since T. b. rhodesiense plasmas showed dyslipidemia and hypertriglyceridemia.…”

Pharmacogenomic implications of the evolutionary history of infectious diseases in Africa

“…rhodesiense causes a more acute illness that progresses rapidly and can lead to death within weeks or months after infection. 96, 97, 98 Regardless of the infecting agent, clinical progression of the illness is divided into two stages, 96 (1) the early or hemolymphatic stage, characterized by nonspecific inflammatory symptoms similar to those associated with malaria or enteric fever, making diagnosis and treatment a challenge, 99 and (2) the late meningoencephalitic stage, characterized by weight loss, behavioral changes, stupor and coma. 96, 100 If left untreated, both can be fatal.…”