Identification and replication of urine metabolites associated with short-term and habitual intake of sweet and fatty snacks in European children and adolescents.

BACKGROUND: Intake of sweet and fatty snacks may partly contribute to the occurrence of obesity and other health conditions in childhood. Traditional dietary assessment methods may be limited in accurately assessing the intake of sweet and fatty snacks in children. Metabolite biomarkers may aid the objective assessment of children's food intake and support establishing diet-disease relationships. OBJECTIVE: The present study aimed to identify biomarkers of sweet and fatty snack intake in two independent cohorts of European children. METHODS: We used data from the IDEFICS/I.Family cohort from baseline (2007/2008) and two follow-up examination waves (2009/2010 and 2013/2014). In total, n=1788 urine samples from 599 children were analysed for untargeted metabolomics using high-resolution liquid chromatography-mass spectrometry. Short-term dietary intake was assessed by 24-hour dietary recalls, and habitual dietary intake was calculated with the National Cancer Institute method. Data from the DONALD cohort of 24-hour urine samples (n=567) and 3-day weighted dietary records were used for external replication of results. Multivariate modelling with Unbiased Variable selection in R (MUVR) algorithms and linear mixed models were used to identify novel biomarkers. Metabolite features significantly associated with dietary intake were then annotated. RESULTS: In total, 66 metabolites were discovered and found to be statistically significant for "chocolate candy", "cakes, puddings & cookies", "candy & sweets", "ice cream", and "crisps". Most of the features (n=62) could not be annotated. Short-term and habitual chocolate intake were positively associated with theobromine, xanthosine, and cyclo(L-prolyl-L-valyl). These results were replicated in the DONALD cohort. Short-term "candy & sweets" intake was negatively associated with octenoylcarnitine. CONCLUSION: We identified potential metabolite biomarkers of sweet and fatty snacks in children, of which three biomarkers of chocolate intake, namely theobromine, xanthosine, and cyclo(L-prolyl-L-valyl) were externally replicated. However, these potential biomarkers require further validation in children.

Combination of gene/protein and metabolite multiomics to reveal biomarkers of nickel ion cytotoxicity and the underlying mechanism.

Biomarkers have been applied for toxicity assessment of biomaterials due to their advantages. However, research on biomarkers for biomaterials is still in its early stages. There is a lack of integrated analysis in biomarker research based on multiomics studies. Herein, we report a new approach for combining of gene/protein and metabolite multiomics to reveal biomarkers of nickel ion (Ni2+) cytotoxicity and the underlying mechanism. Firstly, differentially expressed genes and proteins were compared to screen gene/protein pairs exhibiting consistent differential expression within the same Ni2+-treated groups. Next, metabolic pathway analysis was carried out to reveal pathways in which gene/protein pairs and metabolites showed upstream and downstream relationships. Important networks composed of gene/protein pairs, metabolites and metabolic pathways and candidate biomarkers were subsequently identified. Through expression level and function validation, the gene/protein/metabolite biomarkers were confirmed, and the underlying mechanism was revealed: Ni2+ influenced the expression of the Rrm2 gene biomarker, which subsequently affected the expression of the RRM2 protein biomarker. These changes in turn impacted the levels of uric acid and uridine metabolite biomarkers, ultimately inhibiting DNA synthesis, suppressing cell proliferation, increasing intracellular ROS levels and reducing ATP content.

Metabolomics signatures of sweetened beverages and added sugar are related to anthropometric measures of adiposity in young individuals: results from a cohort study.

BACKGROUND: The associations of sweetened beverages (SBs) and added sugar (AS) intake with adiposity are still debated. Metabolomics could provide insights into the mechanisms linking their intake to adiposity. OBJECTIVES: We aimed to identify metabolomics biomarkers of intake of low- and no-calorie sweetened beverages (LNCSBs), sugar-sweetened beverages (SSBs), and ASs and to investigate their associations with body mass index, body fat percentage, and waist circumference. METHODS: We analyzed 3 data sets from the Dortmund Nutritional and Anthropometric Longitudinally Designed (DONALD) cohort study, of children who provided 2 urine samples (n = 297), adolescents who provided a single urine sample (n = 339), and young adults who provided a single plasma sample (n = 195). Urine and plasma were analyzed using untargeted metabolomics. Dietary intakes were assessed using 3-d weighed dietary records. The random forest, partial least squares, and least absolute shrinkage and selection operator were jointly used for metabolite selection. We examined associations of intakes with metabolites and anthropometric measures using linear and mixed-effects regression. RESULTS: In adolescents, LNCSB were positively associated with acesulfame (ß: 0.0012; 95% confidence interval [CI]: 0.0006, 0.0019) and saccharin (ß: 0.0009; 95% CI: 0.0002, 0.0015). In children, the association was observed with saccharin (ß: 0.0016; 95% CI: 0.0005, 0.0027). In urine and plasma, SSBs were positively associated with 1-methylxanthine (ß: 0.0005; 95% CI: 0.0003, 0.0008; and ß: 0.0010, 95% CI 0.0004, 0.0015, respectively) and 5-acetylamino-6-amino-3-methyluracil (ß: 0.0005; 95% CI: 0.0002, 0.0008; and ß: 0.0009; 95% CI: 0.0003, 0.0014, respectively). AS was associated with urinary sucrose (ß: 0.0095; 95% CI: 0.0069, 0.0121) in adolescents. Some of the food-related metabolomics profiles were also associated with adiposity measures. CONCLUSIONS: We identified SBs- and AS-related metabolites, which may be important for understanding the interplay between these intakes and adiposity in young individuals.

Unravelling the metabolomic diversity of pigmented and non-pigmented traditional rice from Tamil Nadu, India.

Rice metabolomics is widely used for biomarker research in the fields of pharmacology. As a consequence, characterization of the variations of the pigmented and non-pigmented traditional rice varieties of Tamil Nadu is crucial. These varieties possess fatty acids, sugars, terpenoids, plant sterols, phenols, carotenoids and other compounds that plays a major role in achieving sustainable development goal 2 (SDG 2). Gas-chromatography coupled with mass spectrometry was used to profile complete untargeted metabolomics of Kullkar (red colour) and Milagu Samba (white colour) for the first time and a total of 168 metabolites were identified. The metabolite profiles were subjected to data mining processes, including principal component analysis (PCA), Orthogonal Partial Least Square Discrimination Analysis (OPLS-DA) and Heat map analysis. OPLS-DA identified 144 differential metabolites between the 2 rice groups, variable importance in projection (VIP) ≥ 1 and fold change (FC) ≥ 2 or FC ≤ 0.5. Volcano plot (64 down regulated, 80 up regulated) was used to illustrate the differential metabolites. OPLS-DA predictive model showed good fit (R2X = 0.687) and predictability (Q2 = 0.977). The pathway enrichment analysis revealed the presence of three distinct pathways that were enriched. These findings serve as a foundation for further investigation into the function and nutritional significance of both pigmented and non-pigmented rice grains thereby can achieve the SDG 2.

Circulatory Metabolite Ratios as Indicators of Lifestyle Risk Factors Based on a Greek NAFLD Case-Control Study.

An ensemble of confounding factors, such as an unhealthy diet, obesity, physical inactivity, and smoking, have been linked to a lifestyle that increases one's susceptibility to chronic diseases and early mortality. The circulatory metabolome may provide a rational means of pinpointing the advent of metabolite variations that reflect an adherence to a lifestyle and are associated with the occurrence of chronic diseases. Data related to four major modifiable lifestyle factors, including adherence to the Mediterranean diet (estimated on MedDietScore), body mass index (BMI), smoking, and physical activity level (PAL), were used to create the lifestyle risk score (LS). The LS was further categorized into four groups, where a higher score group indicates a less healthy lifestyle. Drawing on this, we analyzed 223 NMR serum spectra, 89 MASLD patients and 134 controls; these were coupled to chemometrics to identify "key" features and understand the biological processes involved in specific lifestyles. The unsupervised analysis verified that lifestyle was the factor influencing the samples' differentiation, while the supervised analysis highlighted metabolic signatures. Τhe metabolic ratios of alanine/formic acid and leucine/formic acid, with AUROC > 0.8, may constitute discriminant indexes of lifestyle. On these grounds, this research contributed to understanding the impact of lifestyle on the circulatory metabolome and highlighted "prudent lifestyle" biomarkers.

Volabolomic Fingerprinting for Post-Mortem Interval Estimation: A Novel Physiological Approach.

Death is a multifaceted process wherein each individual cell and tissue has a metabolic homeostasis and a time of functional cessation defined by the dying process as well as by intrinsic and extrinsic factors. Decomposition is physiologically associated with the release of different types of volatile organic compounds (VOCs), and these form volaboloma mortis. The main purpose of this study was to record the volabolomic fingerprint produced by volatile molecules during the physiological decomposition process of human tissue and muscle cells. The volatile chemical signature has important implications for an open issue in forensics and pathology, namely the estimation of the postmortem interval (PMI), which decreases in accuracy with the passage of time. Volatile metabolites emitted from human tissues and muscle cells at 0, 24, 48, and 72 h were recorded in real time with an electronic nose sensor device. The key findings were the continuous sampling of VOCs emitted from tissues and cells. These showed a common behavior as time progressed; particularly, after 48 h the distributions became dispersed, and after 72 h they became more variable. Volabolomic fingerprinting associated with time progression relevant to the study of PMIs was reconstructed. Additionally, there may be broader applications, such as in dog training procedures for detecting human remains, and perhaps even for studying scavenger and insect attractants.

Metabolomic analysis identifies dysregulation of lipid metabolism in the immune clearance phase of chronic hepatitis B patients.

There is an accelerated progression of liver necroinflammation and fibrosis in the liver during the immune clearance (IC) phase of Chronic hepatitis B virus (HBV) infection, which are critical indicators of antiviral treatment for chronic hepatitis B (CHB) infection. This study applied serum metabolomics to identify the potential metabolite biomarkers for differential diagnosis between the CHB immune tolerance (IT) and Immune clearance (IC) phases. A liquid chromatography-mass spectrometry (LC-MS)-based approach was applied to evaluate and compared the serum metabolic profiles of 28 patients in IT phase and 33 patients in IC phase and appropriate statistical methods with MetaboAnalystR 2.0 R package to analyze those metabolites. The differential metabolites between IT and TC groups were classified and the top altered classification were lipids and lipid-like molecules and fatty acyls, clearly indicating that there were differences in the lipid metabolomic profile of HBV-infected patients with IT vs. IR phase. We identified the top 10 potential metabolite biomarkers for differential diagnosis between IT and IR. There were four lipid metabolites among them and the AUC of two of them, octadecadienoyl-sn-glycero-3-phosphocholine and 3-Cycloheptene-l-acetic acid, were 0.983 and 0.933. octadecadienoyl-sn-glycero-3-phosphocholine is Diacylglycerol (18:2n6/18:0) and 3-Cycloheptene-l-acetic acid is hydroxy fatty acids, both of which were associated with lipid metabolism. This study not only provides the potential metabolic biomarkers but also insight into the mechanism of CHB progression during IT clearance phase.

Identification of metabolite biomarkers in Salmonella enteritidis-contaminated chickens using UHPLC-QTRAP-MS-based targeted metabolomics.

This study aimed to characterize the metabolic profile of Salmonella enteritidis (S. enteritidis) in chicken matrix and to identify metabolic biomarkers of S. enteritidis in chicken. The UHPLC-QTRAP-MS high-throughput targeted metabolomics approach was employed to analyze the metabolic profiles of contaminated and control group chickens. A total of 348 metabolites were quantified, and the application of deep learning least absolute shrinkage and selection operator (LASSO) modelling analysis obtained eight potential metabolite biomarkers for S. enteritidis. Metabolic abundance change analysis revealed significantly enriched abundances of anthranilic acid, l-pyroglutamic acid, 5-hydroxylysine, n,n-dimethylarginine, 4-hydroxybenzoic acid, and menatetrenone in contaminated chicken samples. The receiver operating characteristic (ROC) curve analysis demonstrated the strong ability of these six metabolites as biomarkers to distinguish S. enteritidis contaminated and fresh chicken samples. The findings presented in this study offer a theoretical foundation for developing an innovative approach to identify and detect foodborne contamination caused by S. enteritidis.

Differentiation of patients with and without prostate cancer using urine 1 H NMR metabolomics.

Prostate cancer (PCa) is one of the most prevalent cancers in men worldwide. For its detection, serum prostate-specific antigen (PSA) screening is commonly used, despite its lack of specificity, high false positive rate, and inability to discriminate indolent from aggressive PCa. Following increases in serum PSA levels, clinicians often conduct prostate biopsies with or without advanced imaging. Nuclear magnetic resonance (NMR)-based metabolomics has proven to be promising for advancing early-detection and elucidation of disease progression, through the discovery and characterization of novel biomarkers. This retrospective study of urine-NMR samples, from prostate biopsy patients with and without PCa, identified several metabolites involved in energy metabolism, amino acid metabolism, and the hippuric acid pathway. Of note, lactate and hippurate-key metabolites involved in cellular proliferation and microbiome effects, respectively-were significantly altered, unveiling widespread metabolomic modifications associated with PCa development. These findings support urine metabolomics profiling as a promising strategy to identify new clinical biomarkers for PCa detection and diagnosis.

Untargeted and targeted metabolomics identify metabolite biomarkers for Salmonella enteritidis in chicken meat.

Salmonella Enteritidis easily contaminate chicken during slaughtering, processing, transportation, and sales, which seriously endangers human health. This study aimed to identify metabolite biomarkers for Salmonella Enteritidis contamination in chicken meat. UPLC-Q-Orbitrap MS untargeted metabolomics analysis identified 441 and 240 confidently metabolites in positive and negative ion mode, respectively. Thirty metabolites were defined as potential biomarkers for Salmonella enteritidis contamination in chicken meat. UPLC-QQQ-MS based targeted metabolomics was used to quantitatively analyze candidate metabolite biomarkers in Salmonella enteritidis contaminated and fresh chicken samples. A total of 10 candidate metabolite biomarkers were confirmed in the validation set, among which acetylcholine, l-Methionine, l-Proline, l-Valine, and l-Norleucine were identified as biomarkers for Salmonella Enteritidis contamination in chicken. The combined receiver operating characteristic curve analysis of the five biomarkers achieved an AUC of 0.956, indicating their high sensitivity and specificity in predicting Salmonella Enteritidis in raw chicken. In conclusion, the present study identified five metabolite biomarkers for Salmonella enteritidis in raw chicken. These results provide a potential theoretical basis for developing Salmonella Enteritidis detection methods in raw chicken.

Effects of multi-walled carbon nanotubes in soil on earthworm growth and reproduction, enzymatic activities, and metabolomics.

Increased production and environmental release of multi-walled carbon nanotubes (MWCNTs) increase soil exposure and potential risk to earthworms. However, MWCNT toxicity to earthworms remains unclear, with some studies identifying negative effects and others negligible effects. In this study, to determine whether exposure to MWCNTs negatively affects earthworms and to elucidate possible mechanisms of toxicity, earthworms were exposed to sublethal soil concentrations of MWCNTs (10, 50, and 100 mg/kg) for 28 days. Earthworm growth and reproduction, activities of cytochrome P450 (CYP) isoforms (1A2, 2C9, and 3A4) and antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT), and glutathione-s-transferase (GST)), and metabolomics were determined. Effects of MWCNTs on earthworms depended on exposure concentration. Exposure to MWCNTs did not significantly affect growth and reproduction of individual earthworms. Exposure to 50 mg/kg MWCNTs significantly increased activities of CYP2C9, CYP3A4, SOD, CAT, and GST but clearly reduced levels of L-aspartate, L-asparagine, and glutamine. With exposure to 100 mg/kg MWCNTs, toxic effects on earthworms were observed, with significant inhibition in activities of CYP isoenzymes and SOD, significant reductions in L-aspartate, L-asparagine, glutamine, and tryptophan, and simultaneous accumulations of citrate, isocitrate, fumarate, 2-oxoglutarate, pyruvate, D-galactose, carbamoyl phosphate, formyl anthranilate, hypoxanthine, and xanthine. Results suggest that toxicity of MWCNTs to earthworms is associated with reduced detoxification capacity, excessive oxidative stress, and disturbance of multiple metabolic pathways, including amino acids metabolism, the tricarboxylic acid cycle, pyruvate metabolism, D-galactose metabolism, and purine metabolism. The study provides new insights to better understand and predict the toxicity of MWCNTs in soil.

Corrigendum: Liquid chromatograph-mass spectrometry-based non-targeted metabolomics discovery of potential endogenous biomarkers associated with prostatitis rats to reveal the effects of magnoflorine.

[This corrects the article DOI: 10.3389/fphar.2021.741378.].

Membranous nephropathy: Systems biology-based novel mechanism and traditional Chinese medicine therapy.

Membranous nephropathy (MN) is a renal-limited non-inflammatory autoimmune disease in the glomerulus, which is the second or third main cause of end-stage kidney diseases in patients with primary glomerulonephritis. Substantial achievements have increased our understanding of the aetiology and pathogenesis of murine and human MN. The identification of nephritogenic autoantibodies against neutral endopeptidase, phospholipase A2 receptor (PLA2R) and thrombospondin type-1 domain-containing 7A (THSD7A) antigens provide more specific concept-driven intervention strategies for treatments by specific B cell-targeting monoclonal antibodies to inhibit antibody production and antibody-antigen immune complex deposition. Furthermore, additional antibody specificities for antigens have been discovered, but their pathogenic effects are uncertain. Although anti-PLA2R and anti-THSD7A antibodies as a diagnostic marker is widely used in MN patients, many questions including autoimmune response development, antigenic epitopes, and podocyte damage signalling pathways remain unresolved. This review describes the current available evidence regarding both established and novel molecular mechanisms based on systems biology approaches (gut microbiota, long non-coding RNAs, metabolite biomarkers and DNA methylation) in MN, with an emphasis on clinical findings. This review further summarizes the applications of traditional Chinese medicines such as Tripterygium wilfordii and Astragalus membranaceus for MN treatment. Lastly, this review considers how the identification of novel antibodies/antigens and unresolved questions and future challenges reveal the pathogenesis of MN.

Kidney and plasma metabolomics provide insights into the molecular mechanisms of urate nephropathy in a mouse model of hyperuricemia.

Hyperuricemia (HUA) is closely associated with kidney damage and kidney diseases in humans; however, the underlying mechanisms of HUA-induced kidney diseases remain unknown. In the present study, we examined the kidney and plasma metabolic profiles in a HUA mouse model constructed by knocking out (Ko) the urate oxidase (Uox) gene. The Uox-Ko mice were characterized by an increase in uric acid, glycine, 3'-adenosine monophosphate, citrate, N-acetyl-l-glutamate, l-kynurenine, 5-hydroxyindoleacetate, xanthurenic acid, cortisol, and (-)-prostaglandin e2 together with a decrease of inosine in the kidneys. These altered metabolites confirmed disturbances of purine metabolism, amino acid biosynthesis, tryptophan metabolism, and neuroactive ligand-receptor interaction in Uox-Ko mice. Betaine and biotin were related to kidney function and identified as the potential plasma metabolic biomarker for predicting urate nephropathy (UN). Taken together, these results revealed the underlying pathogenic mechanisms of UN. Investigating these pathways might provide novel targets for the therapeutic intervention of UN and can potentially lead to new treatment strategies.

Blood metabolites predicting mild cognitive impairment in the study of Latinos-investigation of neurocognitive aging (HCHS/SOL).

INTRODUCTION: Blood metabolomics-based biomarkers may be useful to predict measures of neurocognitive aging. METHODS: We tested the association between 707 blood metabolites measured in 1451 participants from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL), with mild cognitive impairment (MCI) and global cognitive change assessed 7 years later. We further used Lasso penalized regression to construct a metabolomics risk score (MRS) that predicts MCI, potentially identifying a different set of metabolites than those discovered in individual-metabolite analysis. RESULTS: We identified 20 metabolites predicting prevalent MCI and/or global cognitive change. Six of them were novel and 14 were previously reported as associated with neurocognitive aging outcomes. The MCI MRS comprised 61 metabolites and improved prediction accuracy from 84% (minimally adjusted model) to 89% in the entire dataset and from 75% to 87% among apolipoprotein E ε4 carriers. DISCUSSION: Blood metabolites may serve as biomarkers identifying individuals at risk for MCI among US Hispanics/Latinos.

Detection of Nail Oncometabolite SAICAR in Oral Cancer Patients and Its Molecular Interactions with PKM2 Enzyme.

Oncometabolites are known to drive metabolic adaptations in oral cancer. Several oncometabolites are known to be shared between cancer cells and non-cancer cells including microbiotas to modulate the tumor microenvironment. Among potential oncometabolites, succinylaminoimidazolecarboxamide ribose5'-phosphate (SAICAR) supports the growth and invasiveness of cancer cells by pyruvate kinase M2 (PKM2) enzyme in a glucose starved tumor microenvironment. There is a significant gap that shows the detection of SAICAR in biological samples including nails of oral cancer patients. Metabolite identification of SAICAR was investigated in the nails of oral cancer patients using novel vertical tube gel electrophoresis (VTGE) and LC-HRMS. Further molecular docking and molecular dynamics simulations (MDS) were employed to determine the nature of molecular interactions of SAICAR (CHEBI ID:18319) with PKM2 (PDB ID: 4G1N). Molecular docking of SAICAR (CHEBI ID:18319) was performed against pyruvate kinase M2 (PDB ID: 4G1N). Data suggest the presence of oncometabolite SAICAR in nails of oral cancer. Molecular docking of SAICAR with PKM2 showed appreciable binding affinity (-8.0 kcal/mol) with residues including ASP407, THR405, GLU410, ARG443, GLY321, ARG436, HIS439, LYS266, and TYR466. Furthermore, MDS confirmed the specific binding of SAICAR within the activator site of PKM2 and the stability of SAICAR and PKM2 molecular interactions. In conclusion, SAICAR is a promising oncometabolite biomarker present in the nails of oral cancer patients. A significant activation potential of SAICAR exists with the PKM2 enzyme.

Liquid Chromatograph-Mass Spectrometry-Based Non-targeted Metabolomics Discovery of Potential Endogenous Biomarkers Associated With Prostatitis Rats to Reveal the Effects of Magnoflorine.

Magnoflorine (Mag) has multiple pharmacological activities for the prevention and treatment of prostatitis. However, its molecular mechanisms andpharmacological targets are not clear. In this study, the ultra-performance liquid tandem mass spectrometry-based metabolomics method was used to clarify the intervention of Mag against prostatitis and the biological mechanism. A total of 25 biomarkers associated with the prostatitis model were identified by metabolomics, and a number of metabolic pathways closely related to the model were obtained by MetPA analysis. After given Mag treatment, the results of each indicator were shown that Mag alkaloid could inhibit the development of prostatitis effectively. We found that Mag had regulative effects on potential biomarkers of prostatitis model, which can regulate them to the control group. Our results indicated that alkaloids have an effective intervention therapy for prostatitis, and five types of metabolic pathways closely related to prostatitis model were obtained, including phenylalanine, tyrosine and tryptophan biosynthesis, phenylalanine metabolism, tyrosine metabolism, arginine and proline metabolism, glycine, serine and threonine metabolism, alanine, aspartate and glutamate metabolism. This study has provided the basic experimental data for the development of Mag in the prevention and treatment of prostatitis.

Metabolomics of Gastric Cancer.

Gastric cancer is the fourth most common malignancy worldwide and the third leading cause of cancer deaths. Recent metabolomics research has advanced our understanding of the relationship between metabolic reprogramming and gastric cancer progression and led to the discovery of metabolic targets for potential clinical applications and therapeutic interventions. As a powerful tool for metabolite and flux measurement, metabolomics not only allows a comprehensive analysis of metabolites and related metabolic pathways but also can investigate the interactions between gastric cancer cells and tumour microenvironment as well as between the cancer cells and gastric microbiome. In this chapter, we aim to summarize the recent advances in gastric cancer metabolism and discuss the applications of metabolomics for target discovery in gastric cancer.

Novel Metabolic Signatures of Prostate Cancer Revealed by 1H-NMR Metabolomics of Urine.

Prostate cancer (PC) is one of the most common male cancers worldwide. Until now, there is no consensus about using urinary metabolomic profiling as novel biomarkers to identify PC. In this study, urine samples from 50 PC patients and 50 non-cancerous individuals (control group) were collected. Based on 1H nuclear magnetic resonance (1H-NMR) analysis, 20 metabolites were identified. Subsequently, principal component analysis (PCA), partial least squares-differential analysis (PLS-DA) and ortho-PLS-DA (OPLS-DA) were applied to find metabolites to distinguish PC from the control group. Furthermore, Wilcoxon test was used to find significant differences between the two groups in metabolite urine levels. Guanidinoacetate, phenylacetylglycine, and glycine were significantly increased in PC, while L-lactate and L-alanine were significantly decreased. The receiver operating characteristics (ROC) analysis revealed that the combination of guanidinoacetate, phenylacetylglycine, and glycine was able to accurately differentiate 77% of the PC patients with sensitivity = 80% and a specificity = 64%. In addition, those three metabolites showed significant differences in patients stratified for Gleason score 6 and Gleason score ≥7, indicating potential use to detect significant prostate cancer. Pathway enrichment analysis using the KEGG (Kyoto Encyclopedia of Genes and Genomes) and the SMPDB (The Small Molecule Pathway Database) revealed potential involvement of KEGG "Glycine, Serine, and Threonine metabolism" in PC. The present study highlights that guanidinoacetate, phenylacetylglycine, and glycine are potential candidate biomarkers of PC. To the best knowledge of the authors, this is the first study identifying guanidinoacetate, and phenylacetylglycine as potential novel biomarkers in PC.

Time-dependent metabolic disorders induced by short-term exposure to polystyrene microplastics in the Mediterranean mussel Mytilus galloprovincialis.

In the modern society, plastic has achieved a crucial status in a myriad of applications because of its favourable properties. Despite the societal benefits, plastic has become a growing global concern due to it is persistence and bioavailability as microplastics (MPs) to aquatic biota. In order to provide mechanistic insights into the early toxicity effects of MPs on aquatic invertebrates, a short-term (up to 72 h) exposure to 3 µm red polystyrene MPs (50 particles/mL) was conducted on marine mussels Mytilus galloprovincialis, selected as model organism for their ability to ingest MPs and their commercial relevance. The use of protonic Nuclear Magnetic Resonance (1H NMR)-based metabolomics, combined with chemometrics, enabled a comprehensive exploration at fixed exposure time-points (T24, T48, T72) of the impact of MPs accumulated in mussel digestive glands, chosen as the major site for pollutants storage and detoxification processes. In detail, 1H NMR metabolic fingerprints of MP-treated mussels were clearly separated from control and grouped for experimental time-points by a Principal Component Analysis (PCA). Numerous metabolites, including amino acids, osmolytes, metabolites involved in energy metabolism, and antioxidants, participating in various metabolic pathways significantly changed over time in MP-exposed mussel digestive glands related to control, reflecting also the fluctuations in MPs accumulation and pointing out the occurrence of disorders in amino acid metabolism, osmotic equilibrium, antioxidant defense system and energy metabolism. Overall, the present work provides the first insights into the early mechanisms of toxicity of polystyrene MPs in marine invertebrates.