Qualitative serum organic acid profiles of HIV-infected individuals not on antiretroviral treatment

The first application of gas chromatography mass spectrometry (GC–MS) metabolomics to the analysis of organic acid profiles in sera of asymptomatic human immunodeficiency virus (HIV)-infected individuals (n = 18) compared to uninfected controls (n = 21), is reported here. Several organic acids are well-established diagnostic biomarkers of mitochondrial dysfunction, making the analysis of the organic acid metabolome well suited to monitoring the progressive disruption of mitochondrial structure and function during HIV infection. Using a multifaceted analytical-bioinformatics procedure, at least 10 of these metabolites could be linked to (1) disrupted mitochondrial metabolism, (2) changes in lipid metabolism and (3) oxidative stress, all of which are aberrations caused by HIV infection. Because of the role of the mitochondria in apoptosis, higher levels of this type of cell death in infected (compared to uninfected) individuals was used to support GC–MS data. This study demonstrates that mass spectrometry metabolomics detects biomarkers of mitochondrial dysfunction which could potentially be developed into indicators of HIV infection, perhaps also to monitor disease progression and the response to antiretroviral treatment.The National Research Foundationhttp://www.springerlink.com/content/1573-3882/nf201

A urinary biosignature for mitochondrial myopathy, encephalopathy, lactic acidosis and stroke like episodes (MELAS)

We used a comprehensive metabolomics approach to study the altered urinary metabolome of two mitochondrial myopathy, encephalopathy lactic acidosis and stroke like episodes (MELAS) cohorts carrying the m.3243A > G mutation. The first cohort were used in an exploratory phase, identifying 36 metabolites that were significantly perturbed by the disease. During the second phase, the 36 selected metabolites were able to separate a validation cohort of MELAS patients completely from their respective control group, suggesting usefulness of these 36 markers as a diagnostic set. Many of the 36 perturbed metabolites could be linked to an altered redox state, fatty acid catabolism and one-carbon metabolism. However, our evidence indicates that, of all the metabolic perturbations caused by MELAS, stalled fatty acid oxidation prevailed as being particularly disturbed. The strength of our study was the utilization of five different analytical platforms to generate the robust metabolomics data reported here. We show that urine may be a useful source for disease-specific metabolomics data, linking, amongst others, altered one-carbon metabolism to MELAS. The results reported here are important in our understanding of MELAS and might lead to better treatment options for the disease.Peer reviewe

Metabolic risks of neonates at birth following in utero exposure to HIV-ART: the amino acid profile of cord blood

Introduction Untargeted metabolomics of cord blood indicated that antiretroviral therapy to HIV-infected mothers (HIV-ART) did not compromise the exposed neonates with regard to the stress of neonatal hypoglycaemia at birth. However, identified biomarkers reflected stress in their energy metabolism, raising concern over developmental risks in some newborns exposed to ART. Objectives This study addresses the concern over HIV-ART-induced metabolic perturbations by expanding the metabolomics study to the amino acid profiles in cord blood collected at birth from newborns either exposed or unexposed to HIV-ART in utero. Methods Amino acid profiles derived from liquid chromatographic triple quadruple spectra of cord blood from neonates exposed and unexposed to HIV-ART (cohort 1) were investigated using a metabolomics approach. Amino acid data, generated by ultra performance liquid chromatography-tandem mass spectrometry from similar cases (cohort 2), were included for comparison. Results Multivariate and supporting statistics indicated differentiation between the exposed and unexposed neonates in both cohorts, caused by a general decrease or downregulation of amino acid concentrations in the cord blood samples from the exposed cases. Specifically, significant upregulation of aspartic acid in both cohorts and downregulation of arginine, and of threonine, tryptophan and lysine in cohorts 1 and 2, respectively, were observed. Conclusions The benefits of ART for HIV-infected pregnant women are well established. However, the amino acid profile of cord blood, obtained from the two independent cohorts, adds to observed metabolic risks of in utero HIV-ART-exposed newborns. These risks could potentially have adverse consequences for the future health of some exposed infant

Uncovering the metabolic response of abalone (Haliotis midae) to environmental hypoxia through metabolomics

Introduction Oxygen is essential for metabolic processes and in the absence thereof alternative metabolic pathways are required for energy production, as seen in marine invertebrates like abalone. Even though hypoxia has been responsible for significant losses to the aquaculture industry, the overall metabolic adaptations of abalone in response to environmental hypoxia are as yet, not fully elucidated. Objective To use a multiplatform metabolomics approach to characterize the metabolic changes associated with energy production in abalone (Haliotis midae) when exposed to environmental hypoxia. Methods Metabolomics analysis of abalone adductor and foot muscle, left and right gill, hemolymph, and epipodial tissue samples were conducted using a multiplatform approach, which included untargeted NMR spectroscopy, untargeted and targeted LC–MS spectrometry, and untargeted and semi-targeted GC-MS spectrometric analyses. Results Increased levels of anaerobic end-products specific to marine animals were found which include alanopine, strombine, tauropine and octopine. These were accompanied by elevated lactate, succinate and arginine, of which the latter is a product of phosphoarginine breakdown in abalone. Primarily amino acid metabolism was affected, with carbohydrate and lipid metabolism assisting with anaerobic energy production to a lesser extent. Different tissues showed varied metabolic responses to hypoxia, with the largest metabolic changes in the adductor muscle. Conclusions From this investigation, it becomes evident that abalone have well-developed (yet understudied) metabolic mechanisms for surviving hypoxic periods. Furthermore, metabolomics serves as a powerful tool for investigating the altered metabolic processes in abalone

One mutation, three phenotypes: novel metabolic insights on MELAS, MIDD and myopathy caused by the m.3243A > G mutation

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