Publications
116 results found
Shariff MIF, Tognarelli JM, Lewis MR, et al., 2015, Plasma Lipid Profiling in a Rat Model of Hepatocellular Carcinoma: Potential Modulation Through Quinolone Administration, JOURNAL OF CLINICAL AND EXPERIMENTAL HEPATOLOGY, Vol: 5, Pages: 286-294, ISSN: 0973-6883
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- Citations: 6
Law TH, Davies ESS, Pan Y, et al., 2015, A randomised trial of a medium-chain TAG diet as treatment for dogs with idiopathic epilepsy, British Journal of Nutrition, Vol: 114, Pages: 1438-1447, ISSN: 1475-2662
Anwar MA, Vorkas PA, Li JV, et al., 2015, Optimization of metabolite extraction of human vein tissue for ultra performance liquid chromatography-mass spectrometry and nuclear magnetic resonance-based untargeted metabolic profiling, Analyst, Vol: 140, Pages: 7586-7597, ISSN: 1364-5528
Human vein tissue is an important matrix to examine when investigating vascular diseases with respect to understanding underlying disease mechanisms. Here, we report the development of an extraction protocol for multi-platform metabolic profiling of human vein tissue. For the first stage of the optimization, two different ratios of methanol/water and 5 organic solvents – namely dichloromethane, chloroform, isopropanol, hexane and methyl tert-butyl ether (MTBE) solutions with methanol – were tested for polar and organic compound extraction, respectively. The extraction output was assessed using 1H Nuclear Magnetic Resonance (NMR) spectroscopy and a panel of Ultra Performance Liquid Chromatography-Mass Spectrometry (UPLC-MS) methodologies. On the basis of the reproducibility of extraction replicates and metabolic coverage, the optimal aqueous (methanol/water) and organic (MTBE/methanol) solvents identified from the first stage were used in a sequential approach for metabolite extraction, altering the order of solvent-mixture addition. The combination of organic metabolite extraction with MTBE/methanol (3 : 1) followed by extraction of polar compounds with methanol/water (1 : 1) was shown to be the best method for extracting metabolites from human vein tissue in terms of reproducibility and number of signals detected and could be used as a single extraction procedure to serve both NMR and UPLC-MS analyses. Molecular classes such as triacylglycerols, phosphatidylcholines, phosphatidylethanolamines, sphingolipids, purines, and pyrimidines were reproducibly extracted. This study enabled an optimal extraction protocol for robust and more comprehensive metabolome coverage for human vein tissue. Many of the physiological and pathological processes affecting the composition of human vein tissue are common to other tissues and hence the extraction method developed in this study can be generically applied.
Vorkas PA, Isaac G, Holmgren A, et al., 2015, Perturbations in fatty acid metabolism and apoptosis are manifested in calcific coronary artery disease: An exploratory lipidomics study, International Journal of Cardiology, Vol: 197, Pages: 192-199, ISSN: 1874-1754
BackgroundControversy exists concerning the beneficial or harmful effects of the presence of ectopic calcification in the coronary arteries. Additionally, further elucidation of the exact pathophysiological mechanism is needed. In this study, we sought to identify metabolic markers of vascular calcification that could assist in understanding the disease, monitoring its progress and generating hypotheses describing its pathophysiology.MethodsUntargeted lipid profiling and complementary modeling strategies were employed to compare serum samples from patients with different levels of calcific coronary artery disease (CCAD) based on their calcium score (CS). Subsequently, patients were divided into three groups: no calcification (NC; CS = 0; n = 26), mild calcification (MC; CS:1–250; n = 27) and severe (SC; CS > 250; n = 17).ResultsPhosphatidylcholine levels were found to be significantly altered in the disease states (p = 0.001–0.04). Specifically, 18-carbon fatty acyl chain (FAC) phosphatidylcholines were detected in lower levels in the SC group, while 20:4 FAC lipid species were detected in higher concentrations. A statistical trend was observed with phosphatidylcholine lipids in the MC group, showing the same tendency as with the SC group. We also observed several sphingomyelin signals present at lower intensities in SC when compared with NC or MC groups (p = 0.000001–0.01).ConclusionsThis is the first lipid profiling study reported in CCAD. Our data demonstrate dysregulations of phosphatidylcholine lipid species, which suggest perturbations in fatty acid elongation/desaturation. The altered levels of the 18-carbon and 20:4 FAC lipids may be indicative of disturbed inflammation homeostasis. The marked sphingomyelin dysregulation in SC is consistent with profound apoptosis as a potential mechanism of CCAD.
Want EJ, Wesseling H, Bahn S, et al., 2015, Hippocampal Proteomic and Metabonomic Abnormalities in Neurotransmission, Oxidative Stress, and Apoptotic Pathways in a Chronic Phencyclidine Rat Model, Journal of Proteome Research, Vol: 14, Pages: 3174-3187, ISSN: 1535-3907
Schizophrenia is a neuropsychiatric disorder affecting 1% of the world’s population. Due to both a broad range of symptoms and disease heterogeneity, current therapeutic approaches to treat schizophrenia fail to address all symptomatic manifestations of the disease. Therefore, disease models that reproduce core pathological features of schizophrenia are needed for the elucidation of pathological disease mechanisms. Here, we employ a comprehensive global label-free liquid chromatography–mass spectrometry proteomic (LC–MSE) and metabonomic (LC–MS) profiling analysis combined with the targeted proteomics (selected reaction monitoring and multiplex immunoassay) of serum and brain tissues to investigate a chronic phencyclidine (PCP) rat model in which glutamatergic hypofunction is induced through noncompetitive NMDAR-receptor antagonism. Using a multiplex immunoassay, we identified alterations in the levels of several cytokines (IL-5, IL-2, and IL-1β) and fibroblast growth factor-2. Extensive proteomic and metabonomic brain tissue profiling revealed a more prominent effect of chronic PCP treatment on both the hippocampal proteome and metabonome compared to the effect on the frontal cortex. Bioinformatic pathway analysis confirmed prominent abnormalities in NMDA-receptor-associated pathways in both brain regions, as well as alterations in other neurotransmitter systems such as kainate, AMPA, and GABAergic signaling in the hippocampus and in proteins associated with neurodegeneration. We further identified abundance changes in the level of the superoxide dismutase enzyme (SODC) in both the frontal cortex and hippocampus, which indicates alterations in oxidative stress and substantiates the apoptotic pathway alterations. The present study could lead to an increased understanding of how perturbed glutamate receptor signaling affects other relevant biological pathways in schizophrenia and, therefore, support drug discovery efforts for the improved
Chekmeneva E, Correia G, Denes J, et al., 2015, Development of nanoelectrospray high resolution isotope dilution mass spectrometry for targeted quantitative analysis of urinary metabolites: application to population profiling and clinical studies, Analytical Methods, Vol: 7, Pages: 5122-5133, ISSN: 1759-9679
An automated chip-based electrospray platform was used to develop a high-throughput nanoelectrospray high resolution mass spectrometry (nESI-HRMS) method for multiplexed parallel untargeted and targeted quantitative metabolic analysis of urine samples. The method was demonstrated to be suitable for metabolic analysis of large sample numbers and can be applied to large-scale epidemiological and stratified medicine studies. The method requires a small amount of sample (5 μL of injectable volume containing 250 nL of original sample), and the analysis time for each sample is three minutes per sample to acquire data in both negative and positive ion modes. Identification of metabolites was based on the high resolution accurate mass and tandem mass spectrometry using authentic standards. The method was validated for 8 targeted metabolites and was shown to be precise and accurate. The mean accuracy of individual measurements being 106% and the intra- and inter-day precision (expressed as relative standard deviations) were 9% and 14%, respectively. Selected metabolites were quantified by standard addition calibration using the stable isotope labelled internal standards in a pooled urine sample, to account for any matrix effect. The multiple point standard addition calibration curves yielded correlation coefficients greater than 0.99, and the linear dynamic range was more than three orders of magnitude. As a proof-of-concept the developed method was applied for targeted quantitative analysis of a set of 101 urine samples obtained from female participants with different pregnancy outcomes. In addition to the specifically targeted metabolites, several other metabolites were quantified relative to the internal standards. Based on the calculated concentrations, some metabolites showed significant differences according to different pregnancy outcomes. The acquired high resolution full-scan data were used for further untargeted fingerprinting and improved the differentiation of
Vorkas PA, Shalhoub J, Isaac G, et al., 2015, Metabolic Phenotyping of Atherosclerotic Plaques Reveals Latent Associations between Free Cholesterol and Ceramide Metabolism in Atherogenesis., Journal of Proteome Research, Vol: 14, Pages: 1389-1399, ISSN: 1535-3907
Current optimum medical treatments have had limited success in the primary prevention of cardiovascular events, underscoring the need for new pharmaceutical targets and enhanced understanding of mechanistic metabolic dysregulation. Here, we use a combination of novel metabolic profiling methodologies, based on ultra-performance liquid chromatography coupled to mass spectrometry (UPLC-MS) followed by chemometric modeling, data integration, and pathway mapping, to create a systems-level metabolic atlas of atherogenesis. We apply this workflow to compare arterial tissue incorporating plaque lesions to intimal thickening tissue (immediate preplaque stage). We find changes in several metabolite species consistent with well-established pathways in atherosclerosis, such as the cholesterol, purine, pyrimidine, and ceramide pathways. We then illustrate differential levels of previously unassociated lipids to atherogenesis, namely, phosphatidylethanolamine-ceramides (t-test p-values: 3.8 × 10(-6) to 9.8 × 10(-12)). Most importantly, these molecules appear to be interfacing two pathways recognized for their involvement in atherosclerosis: ceramide and cholesterol. Furthermore, we show that β-oxidation intermediates (i.e., acylcarnitines) manifest a pattern indicating truncation of the process and overall dysregulation of fatty acid metabolism and mitochondrial dysfunction. We develop a metabolic framework that offers the ability to map significant statistical associations between detected biomarkers. These dysregulated molecules and consequent pathway modulations may provide novel targets for pharmacotherapeutic intervention.
Vorkas PA, Isaac G, Anwar MA, et al., 2015, Untargeted UPLC-MS Profiling Pipeline to Expand Tissue Metabolome Coverage: Application to Cardiovascular Disease., Analytical Chemistry, Vol: 87, Pages: 4184-4193, ISSN: 1086-4377
Metabolic profiling studies aim to achieve broad metabolome coverage in specific biological samples. However, wide metabolome coverage has proven difficult to achieve, mostly because of the diverse physicochemical properties of small molecules, obligating analysts to seek multiplatform and multimethod approaches. Challenges are even greater when it comes to applications to tissue samples, where tissue lysis and metabolite extraction can induce significant systematic variation in composition. We have developed a pipeline for obtaining the aqueous and organic compounds from diseased arterial tissue using two consecutive extractions, followed by a different untargeted UPLC-MS analysis method for each extract. Methods were rationally chosen and optimized to address the different physicochemical properties of each extract: hydrophilic interaction liquid chromatography (HILIC) for the aqueous extract and reversed-phase chromatography for the organic. This pipeline can be generic for tissue analysis as demonstrated by applications to different tissue types. The experimental setup and fast turnaround time of the two methods contributed toward obtaining highly reproducible features with exceptional chromatographic performance (CV % < 0.5%), making this pipeline suitable for metabolic profiling applications. We structurally assigned 226 metabolites from a range of chemical classes (e.g., carnitines, α-amino acids, purines, pyrimidines, phospholipids, sphingolipids, free fatty acids, and glycerolipids) which were mapped to their corresponding pathways, biological functions and known disease mechanisms. The combination of the two untargeted UPLC-MS methods showed high metabolite complementarity. We demonstrate the application of this pipeline to cardiovascular disease, where we show that the analyzed diseased groups (n = 120) of arterial tissue could be distinguished based on their metabolic profiles.
Law TH, Davies E, Yuanlong P, et al., 2015, MEDIUM-CHAIN TRIGLYCERIDE DIET IMPROVES SEIZURE CONTROL IN EPILEPTIC DOGS, 31st International Epilepsy Congress, Publisher: WILEY-BLACKWELL, Pages: 164-164, ISSN: 0013-9580
Miller JA, Pappan K, Thompson PA, et al., 2015, Plasma Metabolomic Profiles of Breast Cancer Patients after Short-term Limonene Intervention, CANCER PREVENTION RESEARCH, Vol: 8, ISSN: 1940-6207
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- Citations: 30
Gabrieli P, Kakani EG, Mitchell SN, et al., 2014, Sexual transfer of the steroid hormone 20E induces the postmating switch in Anopheles gambiae, Proceedings of the National Academy of Sciences of the United States of America, Vol: 111, Pages: 16353-16358, ISSN: 0027-8424
Female insects generally mate multiple times during their lives. A notable exception is the female malaria mosquito Anopheles gambiae, which after sex loses her susceptibility to further copulation. Sex in this species also renders females competent to lay eggs developed after blood feeding. Despite intense research efforts, the identity of the molecular triggers that cause the postmating switch in females, inducing a permanent refractoriness to further mating and triggering egg-laying, remains elusive. Here we show that the male-transferred steroid hormone 20-hydroxyecdysone (20E) is a key regulator of monandry and oviposition in An. gambiae. When sexual transfer of 20E is impaired by partial inactivation of the hormone and inhibition of its biosynthesis in males, oviposition and refractoriness to further mating in the female are strongly reduced. Conversely, mimicking sexual delivery by injecting 20E into virgin females switches them to an artificial mated status, triggering egg-laying and reducing susceptibility to copulation. Sexual transfer of 20E appears to incapacitate females physically from receiving seminal fluids by a second male. Comparative analysis of microarray data from females after mating and after 20E treatment indicates that 20E-regulated molecular pathways likely are implicated in the postmating switch, including cytoskeleton and musculature-associated genes that may render the atrium impenetrable to additional mates. By revealing signals and pathways shaping key processes in the An. gambiae reproductive biology, our data offer new opportunities for the control of natural populations of malaria vectors.
Langer J, Elustondo FA, Chan ECY, et al., 2014, METABOLOMIC ANALYSIS OF GLIOBLASTOMA MULTIFORME UPON ARGININE DEPRIVATION TREATMENT, NEURO-ONCOLOGY, Vol: 16, ISSN: 1522-8517
Langer JK, Chan ECY, Antti H, et al., 2014, METABOLOMIC ANALYSIS OF GLIOBLASTOMA MULTIFORME UPON ARGININE DEPRIVATION TREATMENT, Meeting of the British-Neuro-Oncology-Society (BNOS), Publisher: OXFORD UNIV PRESS INC, ISSN: 1522-8517
Vorkas PA, Holmgren A, Want EJ, et al., 2014, Apoptosis is a potential mechanism for severe calcific coronary artery disease, Annual Meeting of the European-Society-of-Cardiology (ESC), Publisher: OXFORD UNIV PRESS, Pages: 456-456, ISSN: 0195-668X
Vorkas P, Want E, Holmes E, et al., 2014, SIGNIFICANT INFLAMMATION PATHOPHYSIOLOGY FEATURES CALCIFIC CORONARY ARTERY DISEASE, 82nd Congress of the European-Atherosclerosis-Society (EAS), Publisher: ELSEVIER IRELAND LTD, Pages: E140-E140, ISSN: 0021-9150
Vorkas P, Want E, Holmes E, et al., 2014, APOPTOSIS IS A POTENTIAL MECHANISM FOR SEVERE CALCIFIC CORONARY ARTERY DISEASE, 82nd Congress of the European-Atherosclerosis-Society (EAS), Publisher: ELSEVIER IRELAND LTD, Pages: E157-E158, ISSN: 0021-9150
Mirnezami R, Spagou K, Vorkas PA, et al., 2014, Chemical mapping of the colorectal cancer microenvironment via MALDI imaging mass spectrometry (MALDI-MSI) reveals novel cancer-associated field effects, Molecular Oncology, Vol: 8, Pages: 39-49, ISSN: 1574-7891
Matrix‐assisted laser desorption ionisation imaging mass spectrometry (MALDI‐MSI) is a rapidly advancing technique for intact tissue analysis that allows simultaneous localisation and quantification of biomolecules in different histological regions of interest. This approach can potentially offer novel insights into tumour microenvironmental (TME) biochemistry. In this study we employed MALDI‐MSI to evaluate fresh frozen sections of colorectal cancer (CRC) tissue and adjacent healthy mucosa obtained from 12 consenting patients undergoing surgery for confirmed CRC. Specifically, we sought to address three objectives: (1) To identify biochemical differences between different morphological regions within the CRC TME; (2) To characterise the biochemical differences between cancerous and healthy colorectal tissue using MALDI‐MSI; (3) To determine whether MALDI‐MSI profiling of tumour‐adjacent tissue can identify novel metabolic ‘field effects’ associated with cancer. Our results demonstrate that CRC tissue harbours characteristic phospholipid signatures compared with healthy tissue and additionally, different tissue regions within the CRC TME reveal distinct biochemical profiles. Furthermore we observed biochemical differences between tumour‐adjacent and tumour‐remote healthy mucosa. We have referred to this ‘field effect’, exhibited by the tumour locale, as cancer‐adjacent metaboplasia (CAM) and this finding builds on the established concept of field cancerisation.
Shalhoub J, Sikkel MB, Davies KJ, et al., 2014, Systems Biology of Human Atherosclerosis, VASCULAR AND ENDOVASCULAR SURGERY, Vol: 48, Pages: 5-17, ISSN: 1538-5744
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- Citations: 24
Anwar MA, Vorkas P, Li J, et al., 2014, Differential Metabolic Phenotype of Human Varicose Veins Tissue and Their Utility in Understanding Disease Pathogenesis and Identifying Potential Prognostic Biomarkers., Pages: 113-113, ISSN: 2213-333X
Vrijheid M, Slama R, Robinson O, et al., 2014, The human early-life exposome (HELIX): project rationale and design, Environ Health Perspect, Vol: 122, Pages: 535-544, ISSN: 0091-6765
BACKGROUND: Developmental periods in early life may be particularly vulnerable to impacts of environmental exposures. Human research on this topic has generally focused on single exposure-health effect relationships. The "exposome" concept encompasses the totality of exposures from conception onward, complementing the genome. OBJECTIVES: The Human Early-Life Exposome (HELIX) project is a new collaborative research project that aims to implement novel exposure assessment and biomarker methods to characterize early-life exposure to multiple environmental factors and associate these with omics biomarkers and child health outcomes, thus characterizing the "early-life exposome." Here we describe the general design of the project. METHODS: In six existing birth cohort studies in Europe, HELIX will estimate prenatal and postnatal exposure to a broad range of chemical and physical exposures. Exposure models will be developed for the full cohorts totaling 32,000 mother-child pairs, and biomarkers will be measured in a subset of 1,200 mother-child pairs. Nested repeat-sampling panel studies (n = 150) will collect data on biomarker variability, use smartphones to assess mobility and physical activity, and perform personal exposure monitoring. Omics techniques will determine molecular profiles (metabolome, proteome, transcriptome, epigenome) associated with exposures. Statistical methods for multiple exposures will provide exposure-response estimates for fetal and child growth, obesity, neurodevelopment, and respiratory outcomes. A health impact assessment exercise will evaluate risks and benefits of combined exposures. CONCLUSIONS: HELIX is one of the first attempts to describe the early-life exposome of European populations and unravel its relation to omics markers and health in childhood. As proof of concept, it will form an important first step toward the life-course exposome.
Robinson O, Want E, Coen M, et al., 2014, Hirmi Valley liver disease: a disease associated with exposure to pyrrolizidine alkaloids and DDT, J Hepatol, Vol: 60, Pages: 96-102, ISSN: 0168-8278
BACKGROUND & AIMS: Hirmi Valley liver disease was first reported in 2001 in Tigray, Ethiopia. 591 cases, including 228 deaths, were reported up to December 2009. The pyrrolizidine alkaloid acetyllycopsamine was detected in stored grain and residents reported adding the pesticide DDT (dichlorodiphenyldichloroethylene) directly to their food stores. We aimed to characterise the clinical features of the disease, and explore the role of these chemicals in its aetiology. METHODS: 32 cases were examined and full clinical histories taken. Nine cases underwent liver biopsy in hospitals. Serum and urine samples were collected from cases and controls. Urine was analysed for acetyllycopsamine by UPLC-MS. Total DDT in serum was measured by ELISA. Hepatotoxicity of DDT and acetyllycopsamine alone or in combination was explored in C57BL/6J mice. RESULTS: Clinical presentation included epigastric pain, abdominal swelling, bloody diarrhoea, hepatomegaly, splenomegaly, and ascites. Histology revealed acute injury characterised by centrilobular necrosis or chronic injury with bile ductular reaction, cytomegaly and fibrosis but no hepatic vein occlusion. Acetyllycopsamine was detected in urine samples taken in the affected area with significantly greater concentrations in 45 cases than in 43 controls (p=0.02). High levels of DDT (>125 ppb) were detected in 78% of serum samples. In mice, DDT (3 x 75 mg/kg) significantly increased the hepatotoxicity (plasma ALT, p=0.0065) of acetyllycopsamine (750 mg/kg), and in combination induced liver pathology similar to Hirmi Valley liver disease including centrilobular necrosis and cytomegaly. CONCLUSIONS: This novel form of disease appears to be caused by co-exposure to acetyllycopsamine and DDT.
McPhail M, Triantafyllou E, Shawcross D, et al., 2013, Increased apoptotic activity is associated with hospital mortality and disruption in lipid homeostasis in acute-on-chronic liver failure, 64th Annual Meeting and Postgraduate Course of the American-Association-for-the-Study-of-Liver-Diseases, Publisher: WILEY-BLACKWELL, Pages: 851A-852A, ISSN: 0270-9139
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- Citations: 1
Miller JA, Pappan K, Hu C, et al., 2013, Modulation of the serum metabolomic profiles of breast cancer patients after receiving limonene intervention., 104th Annual Meeting of the American-Association-for-Cancer-Research (AACR), Publisher: AMER ASSOC CANCER RESEARCH, ISSN: 0008-5472
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- Citations: 1
Shalhoub J, Vorkas PA, Isaac G, et al., 2013, Metabolic profiling of human atherosclerosis tissue reveals mechanisms of atherosclerosis progression and differences between carotid and femoral plaques, 47th Annual Scientific Meeting of the Vascular-Society-of-Great-Britain-and-Ireland, Publisher: WILEY-BLACKWELL, Pages: 7-7, ISSN: 0007-1323
Want EJ, Masson P, Michopoulos F, et al., 2013, Global metabolic profiling of animal and human tissues via UPLC-MS, NATURE PROTOCOLS, Vol: 8, Pages: 17-32, ISSN: 1754-2189
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- Citations: 569
Anwar MA, Vorkas P, Li J, et al., 2013, Prolonged Mechanical Stretch Alters the Metabolic Profile in Rat Inferior Vena Cava., Pages: 105-106, ISSN: 2213-333X
Anwar MA, Shalhoub J, Vorkas PA, et al., 2012, <i>In-vitro</i> Identification of Distinctive Metabolic Signatures of Intact Varicose Vein Tissue via Magic Angle Spinning Nuclear Magnetic Resonance Spectroscopy, EUROPEAN JOURNAL OF VASCULAR AND ENDOVASCULAR SURGERY, Vol: 44, Pages: 442-450, ISSN: 1078-5884
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- Citations: 14
Want E, 2012, UPLC-MS in metabolomics: from toxicology to disease diagnosis, 22nd IUBMB Congress/37th FEBS Congress, Publisher: WILEY-BLACKWELL, Pages: 37-37, ISSN: 1742-464X
Saric J, Want EJ, Duthaler U, et al., 2012, Systematic Evaluation of Extraction Methods for Multiplatform-Based Metabotyping: Application to the <i>Fasciola hepatica</i> Metabolome, ANALYTICAL CHEMISTRY, Vol: 84, Pages: 6963-6972, ISSN: 0003-2700
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- Citations: 39
Vorkas PA, Naslund U, Want EJ, et al., 2012, Serum metabolic phenotypes correlate with the extent of coronary artery calcification in symptomatic patients with no flow limiting lesions, Congress of the European-Society-of-Cardiology (ESC), Publisher: OXFORD UNIV PRESS, Pages: 283-283, ISSN: 0195-668X
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