ORCID Profile
0000-0002-9088-4799
Current Organisation
Murdoch University
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Publisher: Proceedings of the National Academy of Sciences
Date: 07-2021
Abstract: While the effects of gut microbes on brain development and function have been described, the mechanisms remain largely unknown. Here, we report that tryptophan-metabolizing gut microbes secrete indoles that regulate neurogenesis in the adult hippoc us. This stimulatory effect on adult neurogenesis is mediated by the metabolic- and immune-linked aryl hydrocarbon receptor (AhR). Another AhR ligand, the tryptophan metabolite kynurenine, failed to induce neurogenesis, suggesting ligand specificity of AhR-mediated regulation of adult neurogenesis. The indole-AhR signaling pathway elevates transcription factors and signaling proteins that promote adult neurogenesis, as well as key markers of synaptic maturation. Our data demonstrate a symbiotic gut–brain coregulatory axis that connects the metabolic status of gut microbes to the control of neurogenesis in the adult hippoc us.
Publisher: Springer Science and Business Media LLC
Date: 30-01-2023
DOI: 10.1038/S41590-022-01380-2
Abstract: The biology driving in idual patient responses to severe acute respiratory syndrome coronavirus 2 infection remains ill understood. Here, we developed a patient-centric framework leveraging detailed longitudinal phenotyping data and covering a year after disease onset, from 215 infected in iduals with differing disease severities. Our analyses revealed distinct ‘systemic recovery’ profiles, with specific progression and resolution of the inflammatory, immune cell, metabolic and clinical responses. In particular, we found a strong inter-patient and intra-patient temporal covariation of innate immune cell numbers, kynurenine metabolites and lipid metabolites, which highlighted candidate immunologic and metabolic pathways influencing the restoration of homeostasis, the risk of death and that of long COVID. Based on these data, we identified a composite signature predictive of systemic recovery, using a joint model on cellular and molecular parameters measured soon after disease onset. New predictions can be generated using the online tool shiny.mrc-bsu.cam.ac.uk/apps/covid-19-systemic-recovery-prediction-app , designed to test our findings prospectively.
Publisher: Cold Spring Harbor Laboratory
Date: 08-05-2023
DOI: 10.1101/2023.05.08.23289637
Abstract: We present compelling evidence for the existence of an extended innate viperin dependent pathway which provides crucial evidence for an adaptive response to viral agents like SARS-CoV-2. We show the in vivo biosynthesis of a family of endogenous cytosine metabolites with potential antiviral activity. Two dimensional Nuclear magnetic resonance (NMR) spectroscopy revealed a characteristic spin-system motif indicating the presence of an extended panel of urinary metabolites during the acute viral replication phase. Mass spectrometry additionally allowed the characterization and quantification of the most abundant serum metabolites showing potential diagnostic value of the compounds for viral infections. In total, we unveiled ten nucleoside (cytosine and uracil based) analogue structures, eight of which were previously unknown in humans. The molecular structures of the nucleoside analogues and their correlation with an array of serum cytokines, including IFN-α2, IFN-γ and IL-10, suggest an association with the viperin enzyme contributing to an endogenous innate immune defence mechanism against viral infection.
Publisher: Springer Science and Business Media LLC
Date: 07-01-2022
DOI: 10.1038/S41598-021-03833-4
Abstract: This study aims to explore the immediate effects of bariatric surgery on serum tryptophan–kynurenine pathway metabolites in in iduals with type 2 diabetes and BMI 30. With the goal of providing insight into the link between tryptophan pathway metabolites, type 2 diabetes, and chronic obesity-induced inflammation. This longitudinal study included 20 participants. Half were diagnosed with type 2 diabetes. 11 and 9 underwent RYGB and SG respectively. Blood s les were obtained at pre-operative and 3 months post-operative timepoints. Tryptophan and downstream metabolites of the kynurenine pathway were quantified with an ultrahigh-performance liquid chromatography tandem mass spectrometry with electrospray ionisation method. At 3 months post-operation, RYGB led to significant reductions in tryptophan, kynurenic acid and xanthurenic acid levels when compared to baseline. Significant reductions of the same metabolites after surgery were also observed in in iduals with T2D irrespective of surgical procedure. These metabolites were significantly correlated with serum HbA1c levels and BMI. Bariatric surgery, in particular RYGB reduces serum levels of tryptophan and its downstream kynurenine metabolites. These metabolites are associated with T2D and thought to be potentially mechanistic in the systemic processes of obesity induced inflammation leading to insulin resistance. Its reduction after surgery is associated with an improvement in glycaemic control (HbA1c).
Publisher: American Chemical Society (ACS)
Date: 05-05-2021
Publisher: American Chemical Society (ACS)
Date: 16-03-2021
Publisher: Springer Science and Business Media LLC
Date: 27-08-2018
Publisher: American Chemical Society (ACS)
Date: 24-02-2023
Publisher: Springer Science and Business Media LLC
Date: 10-12-2020
DOI: 10.1038/S41598-020-78031-9
Abstract: Finding early disease markers using non-invasive and widely available methods is essential to develop a successful therapy for Alzheimer’s Disease. Few studies to date have examined urine, the most readily available biofluid. Here we report the largest study to date using comprehensive metabolic phenotyping platforms (NMR spectroscopy and UHPLC-MS) to probe the urinary metabolome in-depth in people with Alzheimer’s Disease and Mild Cognitive Impairment. Feature reduction was performed using metabolomic Quantitative Trait Loci, resulting in the list of metabolites associated with the genetic variants. This approach helps accuracy in identification of disease states and provides a route to a plausible mechanistic link to pathological processes. Using these mQTLs we built a Random Forests model, which not only correctly discriminates between people with Alzheimer’s Disease and age-matched controls, but also between in iduals with Mild Cognitive Impairment who were later diagnosed with Alzheimer’s Disease and those who were not. Further annotation of top-ranking metabolic features nominated by the trained model revealed the involvement of cholesterol-derived metabolites and small-molecules that were linked to Alzheimer’s pathology in previous studies.
Publisher: Springer Science and Business Media LLC
Date: 29-07-2022
DOI: 10.1038/S41598-022-16886-W
Abstract: A growing body of evidence supports the concept of a systemic response to non-severe thermal trauma. This provokes an immunosuppressed state that predisposes paediatric patients to poor recovery and increased risk of secondary morbidity. In this study, to understand the long-term systemic effects of non-severe burns in children, targeted mass spectrometry assays for biogenic amines and tryptophan metabolites were performed on plasma collected from child burn patients at least three years post injury and compared to age and sex matched non-burn (healthy) controls. A panel of 12 metabolites, including urea cycle intermediates, aromatic amino acids and quinolinic acid were present in significantly higher concentrations in children with previous burn injury. Correlation analysis of metabolite levels to previously measured cytokine levels indicated the presence of multiple cytokine-metabolite associations in the burn injury participants that were absent from the healthy controls. These data suggest that there is a sustained immunometabolic imprint of non-severe burn trauma, potentially linked to long-term immune changes that may contribute to the poor long-term health outcomes observed in children after burn injury.
Publisher: Springer Science and Business Media LLC
Date: 09-01-2021
DOI: 10.1186/S13195-020-00741-Z
Abstract: Both serotonergic signalling disruption and systemic inflammation have been associated with the pathogenesis of Alzheimer’s disease (AD). The common denominator linking the two is the catabolism of the essential amino acid, tryptophan. Metabolism via tryptophan hydroxylase results in serotonin synthesis, whilst metabolism via indoleamine 2,3-dioxygenase (IDO) results in kynurenine and its downstream derivatives. IDO is reported to be activated in times of host systemic inflammation and therefore is thought to influence both pathways. To investigate metabolic alterations in AD, a large-scale metabolic phenotyping study was conducted on both urine and serum s les collected from a multi-centre clinical cohort, consisting of in iduals clinically diagnosed with AD, mild cognitive impairment (MCI) and age-matched controls. Metabolic phenotyping was applied to both urine ( n = 560) and serum ( n = 354) from the European-wide AddNeuroMed/Dementia Case Register (DCR) biobank repositories. Metabolite data were subsequently interrogated for inter-group differences influence of gender and age comparisons between two subgroups of MCI - versus those who remained cognitively stable at follow-up visits (sMCI) and those who underwent further cognitive decline (cMCI) and the impact of selective serotonin reuptake inhibitor (SSRI) medication on metabolite concentrations. Results revealed significantly lower metabolite concentrations of tryptophan pathway metabolites in the AD group: serotonin (urine, serum), 5-hydroxyindoleacetic acid (urine), kynurenine (serum), kynurenic acid (urine), tryptophan (urine, serum), xanthurenic acid (urine, serum), and kynurenine/tryptophan ratio (urine). For each listed metabolite, a decreasing trend in concentrations was observed in-line with clinical diagnosis: control MCI AD. There were no significant differences in the two MCI subgroups whilst SSRI medication status influenced observations in serum, but not urine. Urine and serum serotonin concentrations were found to be significantly lower in AD compared with controls, suggesting the bioavailability of the neurotransmitter may be altered in the disease. A significant increase in the kynurenine/tryptophan ratio suggests that this may be a result of a shift to the kynurenine metabolic route due to increased IDO activity, potentially as a result of systemic inflammation. Modulation of the pathways could help improve serotonin bioavailability and signalling in AD patients.
Publisher: MDPI AG
Date: 14-07-2022
DOI: 10.3390/SEPARATIONS9070175
Abstract: Micros les are collections usually less than 50 µL, although all devices that we have captured as part of this review do not fit within this definition (as some can perform collections of up to 600 µL) however, they are considered micros les that can be self-administered. These micros les have been introduced in pre-clinical, clinical, and research settings to overcome obstacles in s ling via traditional venepuncture. However, venepuncture remains the s ling gold standard for the metabolic phenotyping of blood. This presents several challenges in metabolic phenotyping workflows: accessibility for in iduals in rural and remote areas (due to the need for trained personnel), the unamenable nature to frequent s ling protocols in longitudinal research (for its invasive nature), and s le collection difficulty in the young and elderly. Furthermore, venous s le stability may be compromised when the temperate conditions necessary for cold-chain transport are beyond control. Alternatively, research utilising micros les extends phenotyping possibilities to inborn errors of metabolism, therapeutic drug monitoring, nutrition, as well as sport and anti-doping. Although the application of micros les in metabolic phenotyping exists, it is still in its infancy, with whole blood being overwhelmingly the primary biofluid collected through the collection method of dried blood spots. Research into the metabolic phenotyping of micros les is limited however, with advances in commercially available micros ling devices, common barriers such as volumetric inaccuracies and the ‘haematocrit effect’ in dried blood spot micros ling can be overcome. In this review, we provide an overview of the common uses and workflows for micros ling in metabolic phenotyping research. We discuss the advancements in technologies, highlighting key considerations and remaining knowledge gaps for the employment of micros les in metabolic phenotyping research. This review supports the translation of research from the ‘bench to the community’.
Publisher: MDPI AG
Date: 18-07-2023
Abstract: An integrative multi-modal metabolic phenotyping model was developed to assess the systemic plasma sequelae of SARS-CoV-2 (rRT-PCR positive) induced COVID-19 disease in patients with different respiratory severity levels. Plasma s les from 306 unvaccinated COVID-19 patients were collected in 2020 and classified into four levels of severity ranging from mild symptoms to severe ventilated cases. These s les were investigated using a combination of quantitative Nuclear Magnetic Resonance (NMR) spectroscopy and Mass Spectrometry (MS) platforms to give broad lipoprotein, lipidomic and amino acid, tryptophan-kynurenine pathway, and biogenic amine pathway coverage. All platforms revealed highly significant differences in metabolite patterns between patients and controls (n = 89) that had been collected prior to the COVID-19 pandemic. The total number of significant metabolites increased with severity with 344 out of the 1034 quantitative variables being common to all severity classes. Metabolic signatures showed a continuum of changes across the respiratory severity levels with the most significant and extensive changes being in the most severely affected patients. Even mildly affected respiratory patients showed multiple highly significant abnormal biochemical signatures reflecting serious metabolic deficiencies of the type observed in Post-acute COVID-19 syndrome patients. The most severe respiratory patients had a high mortality (56.1%) and we found that we could predict mortality in this patient sub-group with high accuracy in some cases up to 61 days prior to death, based on a separate metabolic model, which highlighted a different set of metabolites to those defining the basic disease. Specifically, hexosylceramides (HCER 16:0, HCER 20:0, HCER 24:1, HCER 26:0, HCER 26:1) were markedly elevated in the non-surviving patient group (Cliff’s delta 0.91–0.95) and two phosphoethanolamines (PE.O 18:0/18:1, Cliff’s delta = −0.98 and PE.P 16:0/18:1, Cliff’s delta = −0.93) were markedly lower in the non-survivors. These results indicate that patient morbidity to mortality trajectories is determined relatively soon after infection, opening the opportunity to select more intensive therapeutic interventions to these “high risk” patients in the early disease stages.
Publisher: Cold Spring Harbor Laboratory
Date: 24-01-2023
DOI: 10.1101/2023.01.24.525337
Abstract: To investigate the underlying molecular mechanisms on how the gut microbe metabolite, indoles, regulate host organ growth and function, germ-free male mice were mono-colonized with indole-producing wildtype Escherichia coli or tryptophanase-encoding tnaA knockout mutant indole-non-producing E. coli . The indole mutant E. coli recipient mice exhibited significant multiorgan decline and growth retardation combined with catabolism and energy deficiency despite increased food intake compared to control mice. In addition, indole mutant mice displayed malfunctional intestine, enlarged caecum, reduced numbers of colonic enterochromaffin cells and reduced circulating serotonin levels, resulting in reduced gut motility, diminished digestion, and lower energy harvest. Furthermore, indole mutant mice also displayed decreased expression of Kcnj12 gene, suggesting reduced excitability of enteric neurons thus adding to intestinal dysfunctional phenotype. In conclusion, indoles are necessary to maintain adult metabolic homeostasis across multiple organs in vivo. Impairment of indole levels results in multiorgan functional decline suggesting a mechanism whereby gut microbe metabolites may regulate biological ageing and thus increase the risk for disease.
Publisher: Wiley
Date: 28-09-2016
DOI: 10.1016/J.JALZ.2016.08.003
Abstract: The aim of this study was to (1) replicate previous associations between six blood lipids and Alzheimer's disease (AD) (Proitsi et al 2015) and (2) identify novel associations between lipids, clinical AD diagnosis, disease progression and brain atrophy (left/right hippoc us/entorhinal cortex). We performed untargeted lipidomic analysis on 148 AD and 152 elderly control plasma s les and used univariate and multivariate analysis methods. We replicated our previous lipids associations and reported novel associations between lipids molecules and all phenotypes. A combination of 24 molecules classified AD patients with >70% accuracy in a test and a validation data set, and we identified lipid signatures that predicted disease progression (R Blood lipids are promising AD biomarkers that may lead to new treatment strategies.
Publisher: American Chemical Society (ACS)
Date: 03-07-2012
DOI: 10.1021/AC300716U
Abstract: Metabolic fingerprinting of biological tissues has become an important area of research, particularly in the biomarker discovery field. Methods have inherent analytical variation, and new approaches are necessary to ensure that the vast numbers of intact metabolites present in biofluids are detected. Here, we describe an in-vial dual extraction (IVDE) method and a direct injection method that shows the total number of features recovered to be over 4500 from a single 20 μL plasma aliquot. By applying a one-step extraction consisting of a lipophilic and hydrophilic layer within a single vial insert, we showed that analytical variation was decreased. This was achieved by reducing s le preparation stages including procedures of drying and transfers. The two phases in the vial, upper and lower, underwent HPLC-QTOF analysis on in idually customized LC gradients in both positive and negative ionization modes. A 60 min lipid profiling HPLC-QTOF method for the lipophilic phase was specifically developed, enabling the separation and putative identification of fatty acids, glycerolipids, glycerophospholipids, sphingolipids, and sterols. The aqueous phase of the extract underwent direct injection onto a 45 min gradient, enabling the detection of both polarities. The IVDE method was compared to two traditional extraction methods. The first method was a two-step ether evaporation and IPA resuspension, and the second method was a methanol precipitation typically used in fingerprinting studies. The IVDE provided a 378% increase in reproducible features when compared to evaporation and a 269% increase when compared to the precipitate and inject method. As a proof of concept, the method was applied to an animal model of diabetes. A 2-fold increase in discriminant metabolites was found when comparing diabetic and control rats with IVDE. These discriminant metabolites accounted for around 600 entities, out of which 388 were identified in available databases.
Publisher: Cold Spring Harbor Laboratory
Date: 30-07-2023
DOI: 10.1101/2023.07.28.550938
Abstract: Impaired wound healing in burn injuries can lead to complications such as skin graft loss, infection, and increased risk of scarring, which impacts long-term patient outcomes and quality of life. While wound repair in severe burns has received substantial research attention, poor wound outcomes in cases of non- severe burns (classified as % of the total body surface area (TBSA)) remain relatively understudied despite also having considerable physiological impact and constituting the majority of hospital admissions for burns. Predicting outcomes in the early stages of healing would decrease financial and patient burden, and aid in preventing long-term complications from poor wound healing. Lipids have been implicated in inflammation and tissue repair processes and may play essential roles in burn wound healing. Longitudinal plasma s les were collected from patients (n=20) with non-severe ( % TBSA) flame or scald burns over a 6-week period including timepoints pre- and post-surgical intervention. S les were analysed using liquid chromatography-tandem mass spectrometry and nuclear magnetic resonance spectroscopy to detect 850 lipid species and 112 lipoproteins. Statistical analyses, including orthogonal projection to latent structures-discriminant analysis was performed to identify changes associated with either re-epithelialisation or delayed wound re-epithelisation. The results demonstrated that the plasma lipid and lipoprotein profiles at admission could predict wound re-epithelisation outcomes at two weeks post-surgery, and that these discriminatory profiles were maintained over a 6-week period. Triacylglycerides, diacylglycerides (DAG) and low density lipoprotein (LDL) subfractions were associated with delayed wound closure, with DAG(18:2_18:3) and LDL/High density lipoprotein (HDL) ratio having the most influence (p-value 0.02, Cliff’s delta 0.7), while HDL subfractions, phosphatidylinositols, phosphatidylcholines (PC), and phosphatidylserines were associated with re-epithelisation at two weeks post-surgery, with PC(16:0_18:1) and HDL-2 apolipoprotein-A1 showing the greatest influence on the model (p-value 0.01, Cliff’s delta -0.7). We demonstrate clinical prediction of wound re-epithelisation in non-severe burn patients using lipid and lipoprotein profiling. Further validation of the models will potentially lead to personalised intervention strategies to enhance injury outcomes, reducing the risk of chronic complications post-burn injury. Demonstration of wound healing prediction from time of hospital admission for non-severe burns. Plasma lipid and lipoprotein profiles within 48 hours of admission to hospital with non-severe burn injury are distinctly different between patients whose wounds re-epithelialized within two weeks and those with delayed re-epithelisation. Patients with delayed wound re-epithelisation have a persistent lipid and lipoprotein signature from burns admission up to six weeks post-injury.
Publisher: Elsevier BV
Date: 02-2021
Publisher: Elsevier BV
Date: 11-2022
DOI: 10.1016/J.BURNS.2022.08.021
Abstract: Surgical wound excision is a necessary procedure for burn patients that require the removal of eschar. The extent of excision is currently guided by clinical judgement, with excessinto healthy tissue potentially leading to excessive scar, or inadequate debridement increasing risk of infection. Thus, an objective real-time measure to facilitate accurate excision could support clinical judgement and improve this surgical procedure. This study was designed to investigate the potential use of Rapid evaporative ionisation mass spectrometry (REIMS) as a tool to support data-driven objective tissue excision. Data were acquired using a multi-platform approach that consisted of both Rapid Evaporative Ionisation Mass Spectrometry (REIMS) performed on intact skin, and comprehensive liquid chromatography-mass spectrometry (LC-MS/MS) lipidomics performed on homogenised skin tissue extracts. Data were analysed using principal components analysis (PCA) and multivariate orthogonal projections to latent squares discriminant analysis (OPLS-DA) and logistic regression to determine the predictability of the models. PCA and OPLS-DA models of the REIMS and LC-MS/MS lipidomics data reported separation of excised and healthy tissue. Molecular fingerprints generated from REIMS analysis of healthy skin tissue revealed a high degree of heterogeneity, however, intra-in idual variance was smaller than inter-in idual variance. Both platforms indicated high levels of skin classification accuracy. In addition, OPLS-DA of the LC-MS/MS lipidomic data revealed significant differences in specific lipid classes between healthy control and excised skin s les including lower free fatty acids (FFA), monoacylglycerols (MAG), lysophosphatidylglycerol (LPG) and lysophosphatidylethanolamines (LPE) in excised tissue and higher lactosylceramides (LCER) and cholesterol esters (CE) compared to healthy control tissue. Having established the heterogeneity in the biochemical composition of healthy skin using REIMS and LC-MS/MS, our data show that REIMS has the potential to distinguish between excied and healthy skin tissue s les. This pilot study suggests that REIMS may be an effective tool to support accurate tissue excision during burn surgery.
Publisher: American Chemical Society (ACS)
Date: 27-08-2020
Publisher: Cold Spring Harbor Laboratory
Date: 19-06-2022
DOI: 10.1101/2022.06.18.22276437
Abstract: The biology driving in idual patient responses to SARS-CoV-2 infection remains ill understood. Here, we developed a patient-centric framework leveraging detailed longitudinal phenotyping data, covering a year post disease onset, from 215 SARS-CoV-2 infected subjects with differing disease severities. Our analyses revealed distinct “systemic recovery” profiles with specific progression and resolution of the inflammatory, immune, metabolic and clinical responses, over weeks to several months after infection. In particular, we found a strong intra-patient temporal covariation of innate immune cell numbers, kynurenine- and host lipid-metabolites, which suggested candidate immunometabolic pathways putatively influencing restoration of homeostasis, the risk of death and of long COVID. Based on these data, we identified a composite signature predictive of systemic recovery on the patient level, using a joint model on cellular and molecular parameters measured soon after disease onset. New predictions can be generated using the online tool shiny.mrc-bsu.cam.ac.uk/apps/covid-systemic-recovery-prediction-app , designed to test our findings prospectively.
Publisher: American Chemical Society (ACS)
Date: 19-05-2021
Publisher: Elsevier BV
Date: 02-2014
Publisher: Elsevier BV
Date: 08-2013
DOI: 10.1016/J.CHROMA.2013.07.029
Abstract: The aim of metabolomics studies is the comprehensive and quantitative analysis of all metabolites in a cell, tissue or organism. This approach requires s le preparation methods to be fast, reproducible and able to extract a wide range of analytes with different polarities, as well as analytical platforms able to detect the extracted metabolites. Recently, we have developed a one-step extraction method consisting of a lipophilic and hydrophilic layer within a single vial insert, in-vial dual extraction (IVDE). In order to check possible application of this method to real biological case, analysis of plasma s les obtained from three streptozotocin-induced diabetic and three control rats was performed. Analytical validity of the method was proved by the calculation (in quality control s les) of relative standard deviation (RSD) for detected metabolites. The percentage of metabolites with RSD<30% was 93% for Fatty acyls, 80% for Glycerolipids, 93% for Glycerophospholipids, 68% for Sterol lipids, and 91% for Sphingolipids. IVDE allowed for selection of more than 600 different features discriminating two studied groups. For around 40% of these masses putative identification was possible. Adequate, with several considerations described within this paper, application of IVDE method enables wide metabolite coverage from a single 20μL plasma aliquot. Within the features putatively identified, glycerolipids and glycerophospholipids arose as the most important groups of compounds discriminating diabetic rats from controls. All discriminating metabolites give an idea of the large metabolic differences that can be present in non-controlled type 1 diabetes.
Publisher: MDPI AG
Date: 03-06-2022
DOI: 10.20944/PREPRINTS202206.0040.V1
Abstract: Micros les (collections usually less than 50 & micro L) have been introduced in pre-clinical, clinical, and research settings to overcome obstacles in s ling via traditional venipuncture. However, venipuncture remains the s ling gold standard for metabolic phenotyping of blood. This pre-sents several challenges in metabolic phenotyping workflows: accessibility for in iduals in ru-ral and remote underserved areas (due to the need for trained personnel), the unamenable nature to frequent s ling protocols in longitudinal research (for its invasive nature), and s le col-lection difficulty in the young and elderly. Furthermore, venous s le stability may be compro-mised when temperate conditions necessary for cold-chain transport are beyond control. Alter-natively, research utilising micros les extends phenotyping possibilities to inborn errors of metabolism, therapeutic drug monitoring, nutrition, as well as sport and anti-doping. Although the application of micros les in metabolic phenotyping exists, it is still in its infancy, with whole blood being overwhelmingly the primary biofluid collected through the collection method of dried blood spots. Research into metabolic phenotyping of micros les is limited however, with advances in commercially available micros ling devices, common barriers such as volumetric inaccuracies and the & lsquo haematocrit effect& rsquo in dried blood spot micros ling can be overcome. In this review, we provide an overview of the common uses and workflows for mi-cros ling in metabolic phenotyping research. We discuss the advancements in technologies, highlighting key considerations and remaining knowledge gaps for employment of micros les in metabolic phenotyping research. Supporting the translation of research from the & lsquo bench to the community& rsquo .
Publisher: MDPI AG
Date: 02-04-2022
Abstract: Mild traumatic brain injury (mTBI) causes structural, cellular and biochemical alterations which are difficult to detect in the brain and may persist chronically following single or repeated injury. Lipids are abundant in the brain and readily cross the blood-brain barrier, suggesting that lipidomic analysis of blood s les may provide valuable insight into the neuropathological state. This study used liquid chromatography-mass spectrometry (LC-MS) to examine plasma lipid concentrations at 11 days following sham (no injury), one (1×) or two (2×) mTBI in rats. Eighteen lipid species were identified that distinguished between sham, 1× and 2× mTBI. Three distinct patterns were found: (1) lipids that were altered significantly in concentration after either 1× or 2× F mTBI: cholesterol ester CE (14:0) (increased), phosphoserine PS (14:0/18:2) and hexosylceramide HCER (d18:0/26:0) (decreased), phosphoinositol PI(16:0/18:2) (increased with 1×, decreased with 2× mTBI) (2) lipids that were altered in response to 1× mTBI only: free fatty acid FFA (18:3 and 20:3) (increased) (3) lipids that were altered in response to 2× mTBI only: HCER (22:0), phosphoethanolamine PE (P-18:1/20:4 and P-18:0/20:1) (increased), lysophosphatidylethanolamine LPE (20:1), phosphocholine PC (20:0/22:4), PI (18:1/18:2 and 20:0/18:2) (decreased). These findings suggest that increasing numbers of mTBI induce a range of changes dependent upon the lipid species, which likely reflect a balance of damage and reparative responses.
Publisher: Wiley
Date: 04-2011
Abstract: Aristolochic acids are known to contribute to various renal disorders therefore, expanding the availability of analytical methodology to detect these compounds is important in order to assess the quality of Chinese herbal medicines in which they can be found. Twelve medicinal herbal s les were procured from various sources and extracted in duplicate prior to a "fingerprint" analysis using conventional HPLC-DAD. Multivariate analysis was performed on the entire chromatographed fingerprints. The resulting output was a partial least-square discriminant analysis model, which was able to evaluate the potential presence of aristolochic acids I and II as well as providing an in idual herbal "fingerprint". The results of this study provide evidence that the presence of aristolochic acids contained within certain herbal extractions could be detected using a simple method, although some limitations apply to this method for quality control, since newly detected s les for aristolochic acid (positives) will need further confirmation with purity checks or MS hyphenation.
Publisher: Proceedings of the National Academy of Sciences
Date: 21-10-2022
Abstract: Genome-wide association studies (GWASs) have identified genetic loci associated with the risk of Alzheimer’s disease (AD), but the molecular mechanisms by which they confer risk are largely unknown. We conducted a metabolome-wide association study (MWAS) of AD-associated loci from GWASs using untargeted metabolic profiling (metabolomics) by ultraperformance liquid chromatography–mass spectrometry (UPLC-MS). We identified an association of lactosylceramides (LacCer) with AD-related single-nucleotide polymorphisms (SNPs) in ABCA7 ( P = 5.0 × 10 −5 to 1.3 × 10 −44 ). We showed that plasma LacCer concentrations are associated with cognitive performance and genetically modified levels of LacCer are associated with AD risk. We then showed that concentrations of sphingomyelins, ceramides, and hexosylceramides were altered in brain tissue from Abca7 knockout mice, compared with wild type (WT) ( P = 0.049–1.4 × 10 −5 ), but not in a mouse model of amyloidosis. Furthermore, activation of microglia increases intracellular concentrations of hexosylceramides in part through induction in the expression of sphingosine kinase, an enzyme with a high control coefficient for sphingolipid and ceramide synthesis. Our work suggests that the risk for AD arising from functional variations in ABCA7 is mediated at least in part through ceramides. Modulation of their metabolism or downstream signaling may offer new therapeutic opportunities for AD.
Publisher: MDPI AG
Date: 20-07-2021
Abstract: Improved methods are required for investigating the systemic metabolic effects of SARS-CoV-2 infection and patient stratification for precision treatment. We aimed to develop an effective method using lipid profiles for discriminating between SARS-CoV-2 infection, healthy controls, and non-SARS-CoV-2 respiratory infections. Targeted liquid chromatography–mass spectrometry lipid profiling was performed on discovery (20 SARS-CoV-2-positive 37 healthy controls 22 COVID-19 symptoms but SARS-CoV-2negative) and validation (312 SARS-CoV-2-positive 100 healthy controls) cohorts. Orthogonal projection to latent structure-discriminant analysis (OPLS-DA) and Kruskal–Wallis tests were applied to establish discriminant lipids, significance, and effect size, followed by logistic regression to evaluate classification performance. OPLS-DA reported separation of SARS-CoV-2 infection from healthy controls in the discovery cohort, with an area under the curve (AUC) of 1.000. A refined panel of discriminant features consisted of six lipids from different subclasses (PE, PC, LPC, HCER, CER, and DCER). Logistic regression in the discovery cohort returned a training ROC AUC of 1.000 (sensitivity = 1.000, specificity = 1.000) and a test ROC AUC of 1.000. The validation cohort produced a training ROC AUC of 0.977 (sensitivity = 0.855, specificity = 0.948) and a test ROC AUC of 0.978 (sensitivity = 0.948, specificity = 0.922). The lipid panel was also able to differentiate SARS-CoV-2-positive in iduals from SARS-CoV-2-negative in iduals with COVID-19-like symptoms (specificity = 0.818). Lipid profiling and multivariate modelling revealed a signature offering mechanistic insights into SARS-CoV-2, with strong predictive power, and the potential to facilitate effective diagnosis and clinical management.
Publisher: American Chemical Society (ACS)
Date: 12-06-2019
Publisher: Future Science Ltd
Date: 05-2011
DOI: 10.4155/BIO.11.62
Abstract: With the number of patients suffering from Alzheimer’s disease rapidly increasing, there is a major requirement for an accurate biomarker capable of diagnosing the disease early. Much of the research is focused on protein and genetic approaches however, small molecules may provide viable marker molecules. Ex les that support this approach include known abnormalities in lipid metabolism, glucose utilization and oxidative stress, which have been demonstrated in patients suffering from the disease. Therefore, by-products of this irregular metabolism may provide accurate biomarkers. In this review we present the current approaches previously published in the literature used to investigate potential small-molecule and metabolite markers, and report their findings. A wide range of techniques are discussed, including separation approaches (LC, GC and CE), magnetic resonance technologies (NMR and magnetic resonance spectroscopy), and immunoassays.
Publisher: Cold Spring Harbor Laboratory
Date: 28-04-2023
DOI: 10.1101/2023.04.24.537960
Abstract: Globally, burns are a significant cause of injury that can cause substantial acute trauma as well as lead to increased incidence of chronic co-morbidity and disease. To date, research has primarily focused on the systemic response to severe injury, with little in the literature reported on impact of non-severe injuries ( % total burn surface area TBSA). To elucidate the metabolic consequences of non-severe burn injury, longitudinal plasma was collected from adults (n=35) who presented at hospital with a non-severe burn injury at admission, and at 6 week follow up. A cross-sectional baseline s le was also collected from non-burn control participants (n=14). S les underwent multiplatform metabolic phenotyping using 1 H nuclear magnetic resonance spectroscopy and liquid chromatography-mass spectrometry to quantify 112 lipoprotein and glycoproteins signatures and 852 lipid species from across 20 subclasses. Multivariate data modelling (Orthogonal projection to latent structures-discriminate analysis) revealed alterations in lipoprotein and lipid metabolism when comparing baseline control to hospital admission s les, with the phenotypic signature found to be sustained at follow up. Univariate (Mann-Whitney U) testing and OPLS-DA indicated specific increases in GlycB (p-value .0e -4 ), low density lipoprotein-2 subfractions (Variable importance in projection score VIP .83e -1 ) and monoacyglyceride (20:4)(p-value .0e -4 ) and decreases in circulating anti-inflammatory high-density lipoprotein-4 subfractions (VIP .75e -1 ), phosphatidylcholines, phosphatidylglycerols, phosphatidylinositols and phosphatidylserines. The results indicate a persistent systemic metabolic phenotype that occurs even in cases of non-severe burn injury. The phenotype is indicative of an acute inflammatory profile which continues to be sustained post-injury, suggesting an impact on systems health beyond the site of injury. The phenotypes contained metabolic signatures consistent with chronic inflammatory states reported to have elevated incidence post-burn injury. Such phenotypic signatures may provide patient stratification opportunities, to identify in idual responses to injury, personalise intervention strategies and improve acute care, reducing risk of chronic co-morbidity.
Publisher: American Chemical Society (ACS)
Date: 17-08-2020
Publisher: MDPI AG
Date: 31-08-2022
Abstract: One of the most recognisable features of ageing is a decline in brain health and cognitive dysfunction, which is associated with perturbations to regular lipid homeostasis. Although ageing is the largest risk factor for several neurodegenerative diseases such as dementia, a loss in cognitive function is commonly observed in adults over the age of 65. Despite the prevalence of normal age-related cognitive decline, there is a lack of effective methods to improve the health of the ageing brain. In light of this, exercise has shown promise for positively influencing neurocognitive health and associated lipid profiles. This review summarises age-related changes in several lipid classes that are found in the brain, including fatty acyls, glycerolipids, phospholipids, sphingolipids and sterols, and explores the consequences of age-associated pathological cognitive decline on these lipid classes. Evidence of the positive effects of exercise on the affected lipid profiles are also discussed to highlight the potential for exercise to be used therapeutically to mitigate age-related changes to lipid metabolism and prevent cognitive decline in later life.
Publisher: American Chemical Society (ACS)
Date: 25-07-2013
DOI: 10.1021/AC401149W
Abstract: High-throughput multiplatform metabolomics experiments are becoming an integral part of clinical and systems biology research. Such methods call for the adoption of robust s le storage and transport formats for small volumes of biofluids. One such format is the dried biofluid spot, which combines small volume requirements with easy portability. Here, we describe ultra high-performance liquid chromatography-mass spectrometry (UHPLC-MS) metabolomics of dried rodent serum, urine, and cerebrospinal fluid spots. An in-vial extraction and UHPLC-MS analysis method was first developed and validated by fingerprinting two test fluids, rat serum and RPMI cell nutrient medium. Data for these extracts were compared in terms of (i) peak area measurements of selected features to assess reproducibility and (ii) total fingerprint variation after data pretreatment. Results showed that percentage peak area variation was found to range between 1.4 and 9.4% relative standard deviation (RSD) for a representative set of molecular features. Upon application of the method to spots bearing serum, urine or cerebrospinal fluid (CSF) from healthy rats and mice, a total of 1,182 and 2,309 reproducible molecular features were obtained in positive and negative ionization modes, respectively, of which 610 (positive) and 991 (negative) were found in both rats and mice. Feature matching was used to detect similarities and differences between biofluids, with the biggest overlap found between fingerprints obtained in urine and CSF. Our results thus demonstrate the potential of such direct fingerprinting of dried biofluid spots as a viable alternative to the use of small (10-15 μL) volumes of neat biofluids in animal studies.
Publisher: American Chemical Society (ACS)
Date: 13-01-2022
DOI: 10.1021/ACS.ANALCHEM.1C04378
Abstract: Liquid chromatography-mass spectrometry (LC-MS) is the main workhorse of metabolomics owing to its high degree of analytical sensitivity and specificity when measuring erse chemistry in complex biological s les. LC-MS-based metabolic profiling of human urine, a biofluid of primary interest for clinical and biobank studies, is not widely considered to be compromised by the presence of endogenous interferences and is often accomplished using a simple "dilute-and-shoot" approach. Yet, it is our experience that broad obscuring signals are routinely observed in LC-MS metabolic profiles and represent interferences that lack consideration in the relevant metabolomics literature. In this work, we chromatographically isolated the interfering metabolites from human urine and unambiguously identified them via
Publisher: American Chemical Society (ACS)
Date: 03-2022
DOI: 10.1021/ACS.ANALCHEM.1C05389
Abstract: SARS-CoV-2 infection causes a significant reduction in lipoprotein-bound serum phospholipids give rise to supramolecular phospholipid composite (SPC) signals observed in diffusion and relaxation edited
Publisher: Springer Science and Business Media LLC
Date: 13-01-2015
DOI: 10.1038/TP.2014.127
Abstract: There is an urgent need for the identification of Alzheimer’s disease (AD) biomarkers. Studies have now suggested the promising use of associations with blood metabolites as functional intermediate phenotypes in biomedical and pharmaceutical research. The aim of this study was to use lipidomics to identify a battery of plasma metabolite molecules that could predict AD patients from controls. We performed a comprehensive untargeted lipidomic analysis, using ultra-performance liquid chromatography/mass spectrometry on plasma s les from 35 AD patients, 40 elderly controls and 48 in iduals with mild cognitive impairment (MCI) and used multivariate analysis methods to identify metabolites associated with AD status. A combination of 10 metabolites could discriminate AD patients from controls with 79.2% accuracy (81.8% sensitivity, 76.9% specificity and an area under curve of 0.792) in a novel test set. Six of the metabolites were identified as long chain cholesteryl esters (ChEs) and were reduced in AD (ChE 32:0, odds ratio (OR)=0.237, 95% confidence interval (CI)=0.10–0.48, P =4.19E−04 ChE 34:0, OR=0.152, 95% CI=0.05–0.37, P =2.90E−04 ChE 34:6, OR=0.126, 95% CI=0.03–0.35, P =5.40E−04 ChE 32:4, OR=0.056, 95% CI=0.01–0.24, P =6.56E−04 and ChE 33:6, OR=0.205, 95% CI=0.06–0.50, P =2.21E−03, per (log2) metabolite unit). The levels of these metabolites followed the trend control MCI AD. We, additionally, found no association between cholesterol, the precursor of ChE and AD. This study identified new ChE molecules, involved in cholesterol metabolism, implicated in AD, which may help identify new therapeutic targets although, these findings need to be replicated in larger well-phenotyped cohorts.
Publisher: American Chemical Society (ACS)
Date: 08-03-2019
Publisher: Elsevier BV
Date: 06-2023
Publisher: Elsevier BV
Date: 02-2016
DOI: 10.1016/J.TOXLET.2015.08.013
Abstract: Current organophosphorus nerve agent medical countermeasures do not directly address the nicotinic effects of poisoning. A series of antinicotinic bispyridinium compounds has been synthesized in our laboratory and screened in vitro. Their actions can include open-channel block at the nicotinic receptor which may contribute to their efficacy. The current lead compound from these studies, MB327 1,1'-(propane-1,3-diyl)bis(4-tert-butylpyridinium) as either the diiodide (I2) or dimethanesulfonate (DMS) has been examined in vivo for efficacy against nerve agent poisoning. MB327 I2 (0-113mgkg(-1)) or the oxime HI-6 DMS (0-100mgkg(- 1)), in combination with atropine and avizafone (each at 3mgkg(-1)) was administered to guinea-pigs 1min following soman poisoning. Treatment increased the LD50 of soman in a dose-dependent manner. The increase was statistically significant (p<0.01) at the 33.9mgkg(-1) (MB327) or 30mgkg(-1) (HI-6) dose with a comparable degree of protection obtained for both compounds. Following administration of 10mgkg(-1) (i.m.), MB327 DMS reached plasma Cmax of 22μM at 12min with an elimination t1/2 of 22min. In an adverse effect study, in the absence of nerve agent poisoning, a dose of 100mgkg(-1) or higher of MB327 DMS was lethal to the guinea-pigs. A lower dose of MB327 DMS (30mgkg(-1)) caused flaccid paralysis accompanied by respiratory impairment. Respiration normalised by 30min, although the animals remained incapacitated to 4h. MB327 or related compounds may be of utility in treatment of nerve agent poisoning as a component of therapy with atropine, anticonvulsant and oxime, or alternatively as an infusion under medical supervision.
Publisher: Elsevier BV
Date: 02-2021
No related grants have been discovered for Luke Whiley.