PubMed

Related Articles Anticancer immunotherapy by CTLA-4 blockade: obligatory contribution of IL-2 receptors and negative prognostic impact of soluble CD25. Cell Res. 2015 Feb;25(2):208-24 Authors: Hannani D, Vétizou M, Enot D, Rusakiewicz S, Chaput N, Klatzmann D, Desbois M, Jacquelot N, Vimond N, Chouaib S, Mateus C, Allison JP, Ribas A, Wolchok JD, Yuan J, Wong P, Postow M, Mackiewicz A, Mackiewicz J, Schadendorff D, Jaeger D, Zörnig I, Hassel J, Korman AJ, Bahjat K, Maio M, Calabro L, Teng MW, Smyth MJ, Eggermont A, Robert C, Kroemer G, Zitvogel L Abstract The cytotoxic T lymphocyte antigen-4 (CTLA-4)-blocking antibody ipilimumab induces immune-mediated long-term control of metastatic melanoma in a fraction of patients. Although ipilimumab undoubtedly exerts its therapeutic effects via immunostimulation, thus far clinically useful, immunologically relevant biomarkers that predict treatment efficiency have been elusive. Here, we show that neutralization of IL-2 or blocking the α and β subunits of the IL-2 receptor (CD25 and CD122, respectively) abolished the antitumor effects and the accompanying improvement of the ratio of intratumoral T effector versus regulatory cells (Tregs), which were otherwise induced by CTLA-4 blockade in preclinical mouse models. CTLA-4 blockade led to the reduction of a suppressive CD4(+) T cell subset expressing Lag3, ICOS, IL-10 and Egr2 with a concomitant rise in IL-2-producing effector cells that lost FoxP3 expression and accumulated in regressing tumors. While recombinant IL-2 improved the therapeutic efficacy of CTLA-4 blockade, the decoy IL-2 receptor α (IL-2Rα, sCD25) inhibited the anticancer effects of CTLA-4 blockade. In 262 metastatic melanoma patients receiving ipilimumab, baseline serum concentrations of sCD25 represented an independent indicator of overall survival, with high levels predicting resistance to therapy. Altogether, these results unravel a role for IL-2 and IL-2 receptors in the anticancer activity of CTLA-4 blockade. Importantly, our study provides the first immunologically relevant biomarker, namely elevated serum sCD25, that predicts resistance to CTLA-4 blockade in patients with melanoma. PMID: 25582080 [PubMed - indexed for MEDLINE]

Related Articles Ultra-trace graphene oxide in a water environment triggers Parkinson's disease-like symptoms and metabolic disturbance in zebrafish larvae. Biomaterials. 2016 Mar 31;93:83-94 Authors: Ren C, Hu X, Li X, Zhou Q Abstract Over the past decade, the safety of nanomaterials has attracted attention due to their rapid development. The relevant health threat of these materials remains largely unknown, particularly at environmentally or biologically relevant ultra-trace concentrations. To address this, we first found that graphene oxide (GO, a carbon nanomaterial that receives extensive attention across various disciplines) at concentrations of 0.01 μg/L-1 μg/L induced Parkinson's disease-like symptoms in zebrafish larvae. In this model, zebrafish showed a loss of more than 90% of dopamine neurons, a 69-522% increase in Lewy bodies (α-synuclein and ubiquitin) and significantly disturbed locomotive activity. Moreover, it was also shown that GO was able to translocate from the water environment to the brain and localize to the nucleus of the diencephalon, thereby inducing structural and morphological damage in the mitochondria. Cell apoptosis and senescence were triggered via oxidative stress, as shown by the upregulation of caspase 8 and β-galactosidase. Using metabolomics, we found that the upregulation of amino acid and some fatty acids (e.g. dodecanoic acid, hexadecanoic acid, octadecenoic acid, nonanoic acid, arachidonic acid, eicosanoic acid, propanoic acid and benzenedicarboxylic acid) metabolism and the downregulation of some other fatty acids (e.g. butanoic acid, phthalic acid and docosenoic acid) are linked to these Parkinson's disease-like symptoms. These findings broaden our understanding of nanomaterial safety at ultra-trace concentrations. PMID: 27085073 [PubMed - as supplied by publisher]

Related Articles Unique microbial-derived volatile organic compounds in portal venous circulation in murine non-alcoholic fatty liver disease. Biochim Biophys Acta. 2016 Apr 13; Authors: Reid DT, McDonald B, Khalid T, Vo T, Schenck LP, Surette MG, Beck PL, Reimer RA, Probert CS, Rioux KP, Eksteen B Abstract BACKGROUND AND AIMS: Non-alcoholic fatty liver disease is now the leading liver disease in North America. The progression of non-alcoholic fatty liver disease to the inflammatory condition, non-alcoholic steatohepatitis is complex and currently not well understood. Intestinal microbial dysbiosis has been implicated in the development of non-alcoholic fatty liver disease and progression of non-alcoholic steatohepatitis. Volatile organic compounds are byproducts of microbial metabolism in the gut that may enter portal circulation and have hepatotoxic effects contributing to the pathogenesis of non-alcoholic steatohepatitis. To test this hypothesis, we measured volatile organic compounds in cecal luminal contents and portal venous blood in a mouse model of non-alcoholic steatohepatitis. METHODS: Gas chromatography-mass spectrometry analysis was conducted on cecal content and portal vein blood for volatile organic compound detection from mice fed a methionine and choline deficient diet, which induces non-alcoholic steatohepatitis. The colonic microbiome was studied by 16S rRNA gene amplification using the Illumina MiSeq platform. RESULTS: Sixty-eight volatile organic compounds were detected in cecal luminal content, a subset of which was also present in portal venous blood. Importantly, differences in portal venous volatile organic compounds were associated with diet-induced steatohepatitis establishing a biochemical link between gut microbiota-derived volatile organic compounds and increased susceptibility to non-alcoholic steatohepatitis. CONCLUSION: Our model creates a novel tool to further study the role of gut-derived volatile organic compounds in the pathogenesis of non-alcoholic steatohepatitis. PMID: 27085070 [PubMed - as supplied by publisher]

Related Articles MBROLE 2.0-functional enrichment of chemical compounds. Nucleic Acids Res. 2016 Apr 15; Authors: López-Ibáñez J, Pazos F, Chagoyen M Abstract Metabolites Biological Role (MBROLE) is a server that performs functional enrichment analysis of a list of chemical compounds derived from a metabolomics experiment, which allows this list to be interpreted in biological terms. Since its release in 2011, MBROLE has been used by different groups worldwide to analyse metabolomics experiments from a variety of organisms. Here we present the latest version of the system, MBROLE2, accessible athttp://csbg.cnb.csic.es/mbrole2 MBROLE2 has been supplemented with 10 databases not available in the previous version, which allow analysis over a larger, richer set of vocabularies including metabolite-protein and drug-protein interactions. This new version performs automatic conversion of compound identifiers from different databases, thus simplifying usage. In addition, the user interface has been redesigned to generate an interactive, more intuitive representation of the results. PMID: 27084944 [PubMed - as supplied by publisher]

Related Articles Longitudinal Metabolite Profiling of Cerebrospinal Fluid in Normal Pressure Hydrocephalus Links Brain Metabolism with Exercise-Induced VEGF Production and Clinical Outcome. Neurochem Res. 2016 Apr 15; Authors: Huang H, Yang J, Luciano M, Shriver LP Abstract Idiopathic normal pressure hydrocephalus is a neurological disease caused by abnormal cerebrospinal fluid flow and presents with symptoms such as dementia. Current therapy involves the removal of excess cerebrospinal fluid by shunting. Not all patients respond to this therapy and biomarkers are needed that could facilitate the characterization of patients likely to benefit from this treatment. Here, we measure brain metabolism in normal pressure hydrocephalus patients by performing a novel longitudinal metabolomic profiling study of cerebrospinal fluid. We find that the levels of brain metabolites correlate with clinical parameters, the amount of vascular endothelial growth factor in the cerebrospinal fluid, and environmental stimuli such as exercise. Metabolomic analysis of normal pressure hydrocephalus patients provides insight into changes in brain metabolism that accompany cerebrospinal fluid disorders and may facilitate the development of new biomarkers for this condition. PMID: 27084769 [PubMed - as supplied by publisher]

Related Articles Metabolomics processing made easier. Comput Methods Programs Biomed. 2016 Jun;129:A1-2 Authors: Lu R, Wu CC, Yang HC, Jack Li YC PMID: 27084327 [PubMed - in process]

Related Articles Peripheral fibroblast metabolic pathway alterations in juvenile rhesus monkeys undergoing long-term fluoxetine administration. Eur Neuropsychopharmacol. 2016 Apr 12; Authors: Su SY, Hogrefe-Phi CE, Asara JM, Turck CW, Golub MS Abstract We report on biochemical pathways perturbed upon chronic fluoxetine administration to juvenile macaques using global metabolomics analyses of fibroblasts derived from skin biopsies. After exposure to tissue culture conditions confounding environmental factors are eliminated and identification of metabolites whose levels are affected by the drug become apparent with a better signal-to-noise ratio compared to data obtained from plasma and cerebrospinal fluid (CSF). Levels of more than 200 metabolites were analyzed to interrogate affected molecular pathways and identify biomarkers of drug response. In addition, we have correlated the metabolomics results with monoamine oxidase (MAOA) genotype and impulsivity behavioral data. Affected pathways include Purine and Pyrimidine metabolisms that have been previously implicated to contribute to neuropsychiatric disorders. PMID: 27084303 [PubMed - as supplied by publisher]

Related Articles Sepsis results in an altered renal metabolic and osmolyte profile. J Surg Res. 2016 May 1;202(1):8-12 Authors: Waltz P, Carchman E, Gomez H, Zuckerbraun B Abstract BACKGROUND: Sepsis remains a major health-care burden and source of morbidity and mortality. Acute kidney injury and failure frequently accompanies severe sepsis and contributes to this burden. Despite a great deal of research, the exact mechanisms underlying renal failure in sepsis are poorly understood. This study aims to further understand metabolic changes in renal tissue during sepsis. MATERIALS AND METHODS: Experimental sepsis was induced by cecal ligation and puncture (CLP) in C57BL/6 mice. Serum and organs were harvested 8 h after CLP. Markers of renal function including serum creatinine, blood urea nitrogen, and cystatin C were measured. Whole kidneys were analyzed for a global biochemical profile via liquid chromatography/tandem mass spectrometry by Metabolon. RESULTS: CLP induced renal injury as evidenced by elevated serum creatinine, blood urea nitrogen, and cystatin C. Global energetic profile in sepsis showed an increase in glycolytic intermediates with decreased flux through the tricarboxylic acid (TCA) cycle. Multiple inflammatory markers were elevated in response to CLP. Levels of osmotic regulators varied, with an overall increase in pinitol, urea, and taurine in response to CLP. CONCLUSIONS: CLP resulted in dramatic changes in the renal macromolecular milieu. There appears to be an increased dependence on glycolysis and diminished flush through the TCA cycle. In addition, changes in renal osmolytes including pinitol, urea, and taurine were observed, perhaps uncovering an additional change with implications on renal function during sepsis. PMID: 27083942 [PubMed - in process]

Related Articles Benzoyl chloride derivatization with liquid chromatography-mass spectrometry for targeted metabolomics of neurochemicals in biological samples. J Chromatogr A. 2016 Apr 4; Authors: Wong JT, Malec PA, Mabrouk OS, Ro J, Dus M, Kennedy RT Abstract Widely targeted metabolomic assays are useful because they provide quantitative data on large groups of related compounds. We report a high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method that utilizes benzoyl chloride labeling for 70 neurologically relevant compounds, including catecholamines, indoleamines, amino acids, polyamines, trace amines, antioxidants, energy compounds, and their metabolites. The method includes neurotransmitters and metabolites found in both vertebrates and insects. This method was applied to analyze microdialysate from rats, human cerebrospinal fluid, human serum, fly tissue homogenate, and fly hemolymph, demonstrating its broad versatility for multiple physiological contexts and model systems. Limits of detection for most assayed compounds were below 10nM, relative standard deviations were below 10%, and carryover was less than 5% for 70 compounds separated in 20min, with a total analysis time of 33min. This broadly applicable method provides robust monitoring of multiple analytes, utilizes small sample sizes, and can be applied to diverse matrices. The assay will be of value for evaluating normal physiological changes in metabolism in neurochemical systems. The results demonstrate the utility of benzoyl chloride labeling with HPLC-MS/MS for widely targeted metabolomics assays. PMID: 27083258 [PubMed - as supplied by publisher]

The oncolytic peptide LTX-315 overcomes resistance of cancers to immunotherapy with CTLA4 checkpoint blockade. Cell Death Differ. 2016 Apr 15; Authors: Yamazaki T, Pitt JM, Vétizou M, Marabelle A, Flores C, Rekdal Ø, Kroemer G, Zitvogel L Abstract Intratumoral immunotherapies aim at reducing local immunosuppression, as well as reinstating and enhancing systemic anticancer T-cell functions, without inducing side effects. LTX-315 is a first-in-class oncolytic peptide-based local immunotherapy that meets these criteria by inducing a type of malignant cell death that elicits anticancer immune responses. Here, we show that LTX-315 rapidly reprograms the tumor microenvironment by decreasing the local abundance of immunosuppressive Tregs and myeloid-derived suppressor cells and by increasing the frequency of polyfunctional T helper type 1/type 1 cytotoxic T cells with a concomitant increase in cytotoxic T-lymphocyte antigen-4 (CTLA4) and drop in PD-1 expression levels. Logically, in tumors that were resistant to intratumoral or systemic CTLA4 blockade, subsequent local inoculation of LTX-315 cured the animals or caused tumor regressions with abscopal effects. This synergistic interaction between CTLA4 blockade and LTX-315 was reduced upon blockade of the β-chain of the interleukin-2 receptor (CD122). This preclinical study provides a strong rationale for administering the oncolytic peptide LTX-315 to patients who are receiving treatment with the CTLA4 blocking antibody ipilimumab.Cell Death and Differentiation advance online publication, 15 April 2016; doi:10.1038/cdd.2016.35. PMID: 27082453 [PubMed - as supplied by publisher]

Data on the changes of the mussels׳ metabolic profile under different cold storage conditions. Data Brief. 2016 Jun;7:951-7 Authors: Aru V, Pisano MB, Savorani F, Engelsen SB, Cosentino S, Cesare Marincola F Abstract One of the main problems of seafood marketing is the ease with which fish and shellfish undergo deterioration after death. (1)H NMR spectroscopy and microbiological analysis were applied to get in depth insight into the effects of cold storage (4 °C and 0 °C) on the spoilage of the mussel Mytilus galloprovincialis. This data article provides information on the average distribution of the microbial loads in mussels׳ specimens and on the acquisition, processing, and multivariate analysis of the (1)H NMR spectra from the hydrosoluble phase of stored mussels. This data article is referred to the research article entitled "Metabolomics analysis of shucked mussels' freshness" (Aru et al., 2016) [1]. PMID: 27081673 [PubMed]

Microbial biotransformation of polyphenols during in vitro colonic fermentation of masticated mango and banana. Food Chem. 2016 Sep 15;207:214-22 Authors: Low DY, Hodson MP, Williams BA, D'Arcy BR, Gidley MJ Abstract Mango and banana cell structures, which survived in vivo mastication and in vitro gastrointestinal digestion, were fermented in vitro for 48h. For both fruits, flavonoids and phenolic acids were liberated and underwent microbial metabolism involving ring fission, dehydroxylation and decarboxylation. UHPLC-PDA/Q-ToF-MS profiles revealed rapid degradation (72-78%) of most intact precursors (epicatechin and several unidentified compounds) within 10h, before the exponential phase of the cumulative gas production. Concomitant formation of catabolites (e.g. 4-hydroxyphenylacetic acid) occurred within 4-8h, while metabolism of catechin derivative and 3-(4-hydroxyphenyl)propanoic acid continued slowly for at least 48h, suggesting intact plant cell walls can be a controlling factor in microbial susceptibility. Untargeted PCA and OPLS-DA demonstrated clear classifications in the compositional fruit type and compound profiles as a function of time. Clusters and distinct discriminating compounds were recognised, which could lead to subsequent biomarker identification for establishing differences in polyphenol microbial metabolism of various fruit matrices. PMID: 27080899 [PubMed - in process]

Methods used to increase the comprehensive coverage of urinary and plasma metabolomes by MS. Bioanalysis. 2016 Apr 15; Authors: Chen Y, Xu J, Zhang R, Abliz Z Abstract Metabolomics, focusing on comprehensive analysis of all the metabolites in a biological system, provides a direct signature of biochemical activity. Using emerging technologies in MS, it is possible to simultaneously and rapidly analyze thousands of metabolites. However, due to the chemical and physical diversity of metabolites, it is difficult to acquire a comprehensive and reliable profiling of the whole metabolome. Here, we summarize the state of the art in metabolomics research, focusing on efforts to provide a more comprehensive metabolome coverage via improvements in two fundamental processes: sample preparation and MS analysis. Additionally, the reliable analysis is also highlighted via the combinations of multiple methods (e.g., targeted and untargeted approaches), and analytical quality control and calibration methods. PMID: 27079429 [PubMed - as supplied by publisher]

20 new pubmed citations were retrieved for your search. Click on the search hyperlink below to display the complete search results: metabolomics These pubmed results were generated on 2016/04/15PubMed comprises more than 24 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.

32 new pubmed citations were retrieved for your search. Click on the search hyperlink below to display the complete search results: metabolomics These pubmed results were generated on 2016/04/14PubMed comprises more than 24 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.

26 new pubmed citations were retrieved for your search. Click on the search hyperlink below to display the complete search results: metabolomics These pubmed results were generated on 2016/04/12PubMed comprises more than 24 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations may include links to full-text content from PubMed Central and publisher web sites.

Effects and mechanisms of Shaofu-Zhuyu decoction and its major bioactive component for Cold - Stagnation and Blood - Stasis primary dysmenorrhea rats. J Ethnopharmacol. 2016 Apr 6; Authors: Huang X, Su S, Duan JA, Sha X, Zhu KY, Guo J, Yu L, Liu P, Shang E, Qian D Abstract ETHNOPHARMACOLOGICAL RELEVANCE: Traditional Chinese medicine (TCM) is used under the guidance of the theory of traditional Chinese medical sciences in clinical application. The Chinese herbal formula, Shaofu Zhuyu decoction (SFZYD), is considered as an effective prescription for treating Cold - Stagnation and Blood - Stasis (CSBS) primary dysmenorrhea. The previous studies showed the SFZYD exhibited great anti-inflammation and analgesic effect. In this present study the metabolomics of CSBS primary dysmenorrhea diseased rats and the cytokine transcription in PHA stimulated-PBMC were investigated to explore the effects and mechanisms. AIM OF THE STUDY: Explore a valuable insight into the effects and mechanisms of SFZYD for Cold - Stagnation and Blood - Stasis primary dysmenorrhea rats. MATERIALS AND METHODS: We established CSBS primary dysmenorrhea diseased rats according the clinical symptoms. A targeted tandem mass spectrometry (MS/MS)-based metabolomic platform was used to evaluate the metabolic profiling changes and the intervention by SFZYD. The PBMC cell was adopted to explore the mechanisms by analyzing the signaling pathway evaluated by expression of inflammatory cytokines, c-jun and c-fos and corresponding phosphorylation levels. RESULTS: Estradiol, oxytocin, progesterone, endothelin, β-endorphin and PGF2α were restored back to the normal level after the treatment of SFZYD. Total twenty-five metabolites (ten in plasma and fifteen in urine), up-regulated or down-regulated, were identified. These identified biomarkers underpinning the metabolic pathway including pentose and glucuronate interconversions, steroid hormone biosynthesis, and glycerophospholipid metabolism are disturbed in model rats. Among these metabolites, twenty one potential biomarkers were regulated after SFZYD treated. The compound of paeoniflorin, a major bioactive compound in SFZYD, was proved to regulate the MAPK signaling pathway by inhibiting the expression of IL-1β, IL-2, IL-10, IL-12, TNFα, INFγ, C-jun and C-fos in PHA stimulated-PBMC. CONCLUSION: These findings indicated that SFZYD improved the metabolic profiling and biochemical indicators on CSBS primary dysmenorrhea rats. And the mechanisms were closely related with the regulation of the MAPK pathway by reduction in phosphorylated forms of the three MAPK (ERK1/2, p38 and JNK) and down regulation of c-jun and c-fos by paeoniflorin. The data could be provided the guidance for further research and new drug discovery. PMID: 27060631 [PubMed - as supplied by publisher]

Isolation and characterization of a mutant defective in triacylglycerol accumulation in nitrogen-starved Chlamydomonas reinhardtii. Biochim Biophys Acta. 2016 Apr 6; Authors: Hung CH, Kanehara K, Nakamura Y Abstract Triacylglycerol (TAG), a major source of biodiesel production, accumulates in nitrogen-starved Chlamydomonas reinhardtii. However, the metabolic pathway of starch-to-TAG conversion remains elusive because an enzyme that affects the starch degradation is unknown. Here, we isolated a new class of mutant bgal1, which expressed an overaccumulation of starch granules and defective photosynthetic growth. The bgal1 was a null mutant of a previously uncharacterized β-galactosidase-like gene (Cre02.g119700), which decreased total β-galactosidase activity 40% of wild type. Upon nitrogen starvation, the bgal1 mutant showed decreased TAG accumulation mainly due to the reduced flux of de novo TAG biosynthesis evidenced by increased unsaturation of fatty acid composition in TAG and reduced TAG accumulation by additional supplementation of acetate to the culture media. Metabolomic analysis of the bgal1 mutant showed significantly reduced levels of metabolites following the hydrolysis of starch and substrates for TAG accumulation, whereas metabolites in TCA cycle were unaffected. Upon nitrogen starvation, while levels of glucose 6-phosphate, fluctose 6-phosphate and acetyl-CoA remained lower, most of the other metabolites in glycolysis were increased but those in the TCA cycle were decreased, supporting TAG accumulation. We suggest that BGAL1 may be involved in the degradation of starch, which affects TAG accumulation in nitrogen-starved C. reinhardtii. PMID: 27060488 [PubMed - as supplied by publisher]

Dietary vitamin A supplementation ameliorates the effects of poly-aromatic hydrocarbons in Atlantic salmon (Salmo salar). Aquat Toxicol. 2016 Mar 21;175:171-183 Authors: Berntssen MH, Ørnsrud R, Rasinger J, Søfteland L, Lock EJ, Kolås K, Moren M, Hylland K, Silva J, Johansen J, Lie K Abstract Several studies have reported on the interaction between vitamin A (VA) and aryl hydrocarbon receptor (AhR)-binding toxicants, including poly-aromatic hydrocarbons (PAHs). In aquaculture, the use of plant oils in novel aquafeeds can increase PAH levels while simultaneously lowering natural VA background levels, causing the need to supplement plant oil-based feeds with synthetic VA. To study dietary VA-PAH interactions, Atlantic salmon (initial weight 195±0.15g) were fed four identical plant-based diets that were supplemented with PAHs (100 and 10mgkg(-1) benzo[a]pyrene (BaP) and phenanthrene (Phe), respectively) or VA (retinyl acetate 8721IUkg(-1)) separately or combined for 2.5 months in a 2×2 factorial design, with triplicate net-pens per diet. Dietary PAH significantly reduced hepatic VA storage, and VA-enriched diets restored hepatic VA. There was a significant PAH-VA interaction effect on hepatic BaP, but not Phe, accumulation, with reduced hepatic BaP concentrations in fish fed VA+PAH compared to fish fed PAH alone. Concurrently, PAH and VA significantly interacted in their effects on CYP1A phase I biotransformation as observed from increased ethoxyresorufin-O-deethylase (EROD) activity, increased CYP1A protein concentration, and elevated transcription (cyp1a1 gene expression) in fish fed PAH+VA compared to PAH alone. Dietary VA supplementation alone had no significant effect on CYP1A phase I biotransformation. Metabolomic assessment showed that dietary VA caused a restoration of metabolic intermediates involved in energy metabolism that were affected by dietary PAH. Moreover, a PAH-induced growth inhibition was partially ameliorated by dietary VA supplementation. In conclusion, dietary VA interacted with PAH toxicity on the level of CYP1A-mediated detoxification, hepatic PAH accumulation, energy allocation, and growth. PMID: 27060237 [PubMed - as supplied by publisher]

Repeated implantation failure versus repeated implantation success: discrimination at a metabolomic level. Hum Reprod. 2016 Apr 8; Authors: RoyChoudhury S, Singh A, Gupta NJ, Srivastava S, Joshi MV, Chakravarty B, Chaudhury K Abstract STUDY QUESTION: Is there any difference at the serum metabolic level between women with recurrent implantation failure (RIF) and women with recurrent implantation success (RIS) when undergoing in vitro fertilization (IVF)? SUMMARY ANSWER: Eight metabolites, including valine, adipic acid, l-lysine, creatine, ornithine, glycerol, d-glucose and urea, were found to be significantly up-regulated in women with RIF when compared with women with RIS. WHAT IS KNOWN ALREADY: Despite transfer of three high-grade embryos per cycle, RIF following three or more consecutive IVF attempts occurs in a group of infertile women. Conversely, there is a group of women who undergo successful implantation each cycle, yet have a poor obstetric history. STUDY DESIGN, SIZE, DURATION: This study was conducted over a period of 10 years (January 2004-October 2014). Groups of 28 women with RIF (age ≤40 years and BMI ≤28) and 24 women with RIS (age and BMI matched) were selected from couples with primary infertility reporting at the Institute of Reproductive Medicine, Kolkata, India. Women recruited in the RIF group had history of implantation failure in at least three consecutive IVF attempts, in which three embryos of high-grade quality were transferred in each cycle. PARTICIPANTS/MATERIALS, SETTING, METHODS: Blood samples were collected from both the groups during the implantation window following overnight fasting for at least 10 h (7-10 days post ovulation). Samples were analyzed using a 700 MHz NMR spectrometer and acquired spectra were subjected to chemometric and statistical analysis. Serum levels of endothelial nitric oxide synthase (eNOS) were measured using an enzyme immunoassay technique. MAIN RESULTS AND THE ROLE OF CHANCE: Valine, adipic acid, l-lysine, creatine, ornithine, glycerol, d-glucose and urea were found to be significantly down-regulated in women with RIS when compared with those with RIF, with fold change values of 0.81, 0.82, 0.79, 0.80, 0.78, 0.68, 0.76 and 0.74, respectively. Further, serum eNOS was found to be significantly lower in women with RIF when compared with RIS (P < 0.05), indicating possible impairment in nitric oxide production. Metabolites, mostly related to energy metabolism, lipid metabolism and the arginine metabolic pathway were found to be considerably altered and are likely to be associated with the RIF phenomenon. However, the interplay between these molecules in RIF is complex and holds merit for further exploration. LIMITATIONS, REASONS FOR CAUTION: In-depth studies of the arginine metabolic pathway in endometrial tissues seem necessary to validate our findings. A limitation of the present study is that the metabolic level changes, eNOS and nitric oxide levels have not been investigated in the endometrial tissues of the two groups of women. It would be interesting to investigate whether there exists a direct link between metabolic dysregulation and genetic factors that affects implantation in RIF women. WIDER IMPLICATIONS OF THE FINDINGS: We speculate that tissue metabolomics can provide an improved understanding of the metabolic dysfunction associated with RIF. The identification of serum metabolic marker(s) in women with RIS may help with strategies of early therapeutic intervention, which may improve the chances of implantation significantly in women otherwise susceptible to IVF failure. STUDY FUNDING/COMPETING INTERESTS: One of the authors, S.R.C. acknowledges the Council of Scientific and Industrial Research (CSIR), Government of India [No: 9/81(1228)/14, EMR-I] for financial support. PMID: 27060172 [PubMed - as supplied by publisher]