A multiplatform metabolomics approach for comprehensive analysis of GIST xenografts with various KIT mutations

Metabolites in biological matrices belong to diverse chemical groups, ranging from non-polar long-chain fatty acids to small polar molecules. The goal of untargeted metabolomic analysis is to measure the highest number of metabolites in the sample. Nevertheless, from an analytical point of view, no single technique can measure such a broad spectrum of analytes. Therefore, we selected a method based on GC-MS and LC-MS with two types of stationary phases for the untargeted profiling of gastrointestinal stromal tumours. The procedure was applied to GIST xenograft samples (n = 71) representing four different mutation models, half of which were treated with imatinib. We aimed to verify the method coverage and advantages of applying each technique. RP-LC-MS measured most metabolites due to a significant fraction of lipid components of the tumour tissue. What is unique and worth noting is that all applied techniques were able to distinguish between different mutation models. However, for detecting imatinib-induced alterations in the GIST metabolome, RP-LC-MS and GC-MS proved to be more relevant than HILIC-LC-MS, resulting in a higher number of significantly changed metabolites in four treated models. Undoubtedly, the inclusion of all mentioned techniques makes the method more comprehensive. Nonetheless, for green chemistry and time and labour saving, we assume that RP-LC-MS and GC-MS analyses are sufficient to cover the global GIST metabolome.

Targeted and untargeted metabolomic approach for GDM diagnosis

Gestational diabetes mellitus (GDM) is a disorder which manifests itself for the first time during pregnancy and is mainly connected with glucose metabolism. It is also known that fatty acid profile changes in erythrocyte membranes and plasma could be associated with obesity and insulin resistance. These factors can lead to the development of diabetes. In the reported study, we applied the untargeted analysis of plasma in GDM against standard glucose-tolerant (NGT) women to identify the differences in metabolomic profiles between those groups. We found higher levels of 2-hydroxybutyric and 3-hydroxybutyric acids. Both secondary metabolites are associated with impaired glucose metabolism. However, they are products of different metabolic pathways. Additionally, we applied lipidomic profiling using gas chromatography to examine the fatty acid composition of cholesteryl esters in the plasma of GDM patients. Among the 14 measured fatty acids characterizing the representative plasma lipidomic cluster, myristic, oleic, arachidonic, and α-linoleic acids revealed statistically significant changes. Concentrations of both myristic acid, one of the saturated fatty acids (SFAs), and oleic acid, which belong to monounsaturated fatty acids (MUFAs), tend to decrease in GDM patients. In the case of polyunsaturated fatty acids (PUFAs), some of them tend to increase (e.g., arachidonic), and some of them tend to decrease (e.g., α-linolenic). Based on our results, we postulate the importance of hydroxybutyric acid derivatives, cholesteryl ester composition, and the oleic acid diminution in the pathophysiology of GDM. There are some evidence suggests that the oleic acid can have the protective role in diabetes onset. However, metabolic alterations that lead to the onset of GDM are complex; therefore, further studies are needed to confirm our observations.

Common Strategies and Factors Affecting Off-Line Breath Sampling and Volatile Organic Compounds Analysis Using Thermal Desorption-Gas Chromatography-Mass Spectrometry (TD-GC-MS)

An analysis of exhaled breath enables specialists to noninvasively monitor biochemical processes and to determine any pathological state in the human body. Breath analysis holds the greatest potential to remold and personalize diagnostics; however, it requires a multidisciplinary approach and collaboration of many specialists. Despite the fact that breath is considered to be a less complex matrix than blood, it is not commonly used as a diagnostic and prognostic tool for early detection of disordered conditions due to its problematic sampling, analysis, and storage. This review is intended to determine, standardize, and marshal experimental strategies for successful, reliable, and especially, reproducible breath analysis.

Low and high resolution gas chromatography-mass spectrometry for untargeted metabolomics: A tutorial

GC-MS for untargeted metabolomics is a well-established technique. Small molecules and molecules made volatile by derivatization can be measured and those compounds are key players in main biological pathways. This tutorial provides ready-to-use protocols for GC-MS-based metabolomics, using either the well-known low-resolution approach (GC-Q-MS) with nominal mass or the more recent high-resolution approach (GC-QTOF-MS) with accurate mass, discussing their corresponding strengths and limitations. Analytical procedures are covered for different types of biofluids (plasma/serum, bronchoalveolar lavage, urine, amniotic fluid) tissue samples (brain/hippocampus, optic nerve, lung, kidney, liver, pancreas) and samples obtained from cell cultures (adipocytes, macrophages, Leishmania promastigotes, mitochondria, culture media). Together with the sample preparation and data acquisition, data processing strategies are described specially focused on Agilent equipments, including deconvolution software and database annotation using spectral libraries. Manual curation strategies and quality control are also deemed. Finally, considerations to obtain a semiquantitative value for the metabolites are also described. As a case study, an illustrative example from one of our experiments at CEMBIO Research Centre, is described and findings discussed.

A Robust Method for Sample Preparation of Gastrointestinal Stromal Tumour for LC/MS Untargeted Metabolomics

Gastrointestinal stromal tumour has already been well explored at the genome level; however, little is known about metabolic processes occurring in the sarcoma. Sample preparation is a crucial step in untargeted metabolomics workflow, highly affecting the metabolome coverage and the quality of the results. In this study, four liquid-liquid extraction methods for the isolation of endogenous compounds from gastrointestinal stromal tumours were compared and evaluated. The protocols covered two-step or stepwise extraction with methyl-tert-butyl ether (MTBE) or dichloromethane. The extracts were subjected to LC-MS analysis by the application of reversed-phase and hydrophilic interaction liquid chromatography to enable the separation and detection of both polar and nonpolar analytes. The extraction methods were compared in terms of efficiency (total number of detected metabolites) and reproducibility. The method was based on the stepwise extraction with MTBE, methanol, and water proved to be the most reproducible, and thus, its robustness to fluctuations in experimental conditions was assessed employing Plackett–Burman design and hierarchical modelling. While most studied factors had no effect on the metabolite abundance, the highest coefficient value was observed for the volume of MTBE added during extraction. Herein, we demonstrate the application and the feasibility of the selected protocol for the analysis of gastrointestinal stromal tumour samples. The method selected could be considered as a reference for the best characterization of underlying molecular changes associated with complex tissue extracts of GIST.

Comprehensive Metabolic Signature of Renal Dysplasia in Children. A Multiplatform Metabolomics Concept

Renal dysplasia is a severe congenital abnormality of the kidney parenchyma, which is an important cause of end-stage renal failure in childhood and early adulthood. The diagnosis of renal dysplasia relies on prenatal or postnatal ultrasounds as children show no specific clinical symptoms before chronic kidney disease develops. Prompt diagnosis is important in terms of early introduction of nephroprotection therapy and improved long-term prognosis. Metabolomics was applied to study children with renal dysplasia to provide insight into the changes in biochemical pathways underlying its pathology and in search of early indicators for facilitated diagnosis. The studied cohort consisted of 72 children, 39 with dysplastic kidneys and 33 healthy controls. All subjects underwent comprehensive urine metabolic profiling with the use of gas chromatography and liquid chromatography coupled to mass spectrometry, with two complementary separation modes of the latter. Univariate and multivariate statistical calculations identified a total of nineteen metabolites, differentiating the compared cohorts, independent of their estimated glomerular filtration rate. Seven acylcarnitines, xanthine, and glutamine were downregulated in the urine of renal dysplasia patients. Conversely, renal dysplasia was associated with higher urinary levels of dimethylguanosine, threonic acid or glyceric acid. This is the first metabolomic study of subjects with renal dysplasia. The authors define a characteristic urine metabolic signature in children with dysplastic kidneys, irrespective of renal function, linking the condition with altered fatty acid oxidation, amino acid and purine metabolisms.

Plasma Metabolome Alterations Associated with Extrauterine Growth Restriction

Very preterm infants (VPI, born at or before 32 weeks of gestation) are at risk of adverse health outcomes, from which they might be partially protected with appropriate postnatal nutrition and growth. Metabolic processes or biochemical markers associated to extrauterine growth restriction (EUGR) have not been identified. We applied untargeted metabolomics to plasma samples of VPI with adequate weight for gestational age at birth and with different growth trajectories (29 well-grown, 22 EUGR) at the time of hospital discharge. A multivariate analysis showed significantly higher levels of amino-acids in well-grown patients. Other metabolites were also identified as statistically significant in the comparison between groups. Relevant differences (with corrections for multiple comparison) were found in levels of glycerophospholipids, sphingolipids and other lipids. Levels of many of the biochemical species decreased progressively as the level of growth restriction increased in severity. In conclusion, an untargeted metabolomic approach uncovered previously unknown differences in the levels of a range of plasma metabolites between well grown and EUGR infants at the time of discharge. Our findings open speculation about pathways involved in growth failure in preterm infants and the long-term relevance of this metabolic differences, as well as helping in the definition of potential biomarkers.

Short overview on metabolomics approach to study pathophysiology of oxidative stress in cancer

Association of oxidative stress with carcinogenesis is well known, but not understood well, as is pathophysiology of oxidative stress generated during different types of anti-cancer treatments. Moreover, recent findings indicate that cancer associated lipid peroxidation might eventually help defending adjacent nonmalignant cells from cancer invasion. Therefore, untargeted metabolomics studies designed for advanced translational and clinical studies are needed to understand the existing paradoxes in oncology, including those related to controversial usage of antioxidants aiming to prevent or treat cancer. In this short review we have tried to put emphasis on the importance of pathophysiology of oxidative stress and lipid peroxidation in cancer development in relation to metabolic adaptation of particular types of cancer allowing us to conclude that adaptation to oxidative stress is one of the main driving forces of cancer pathophysiology. With the help of metabolomics many novel findings are being achieved thus encouraging further scientific breakthroughs. Combined with targeted qualitative and quantitative methods, especially immunochemistry, further research might reveal bio-signatures of individual patients and respective malignant diseases, leading to individualized treatment approach, according to the concepts of modern integrative medicine.

Quality assurance procedures for mass spectrometry untargeted metabolomics. a review

Untargeted metabolomics, as a global approach, has already proven its great potential and capabilities for the investigation of health and disease, as well as the wide applicability for other research areas. Although great progress has been made on the feasibility of metabolomics experiments, there are still some challenges that should be faced and that includes all sources of fluctuations and bias affecting every step involved in multiplatform untargeted metabolomics studies. The identification and reduction of the main sources of unwanted variation regarding the pre-analytical, analytical and post-analytical phase of metabolomics experiments is essential to ensure high data quality. Nowadays, there is still a lack of information regarding harmonized guidelines for quality assurance as those available for targeted analysis. In this review, sources of variations to be considered and minimized along with methodologies and strategies for monitoring and improvement the quality of the results are discussed. The given information is based on evidences from different groups among our own experiences and recommendations for each stage of the metabolomics workflow. The comprehensive overview with tools presented here might serve other researchers interested in monitoring, controlling and improving the reliability of their findings by implementation of good experimental quality practices in the untargeted metabolomics study.

Abstract 5055: Multiplatform metabolomics analysis of growth arrest in pancreatic tumor xenografts

R,S-4-Methoxy-1-naphthylfenoterol, MNF, inhibits the G protein-coupled receptor GPR55. In this study, we determine the effect of MNF on human PANC-1 pancreatic tumor growth in mice and apply multiplatform metabolomics analysis to identify pathways associated with growth arrest.

Methods: Female Balb/c nude mice, 6-8 weeks old, 18-20g, were inoculated subcutaneously with 5 x 106 PANC-1 cells. On Day 8, mice were placed in groups of 10 using random block design based upon tumor volume. Mice received daily ip injections of vehicle or 40mgxkg-1 MNF 5 days/week for 3 treatment cycles. Mice were monitored daily and tumor volumes measured at beginning and end of each dosing cycle. On Day 33, mice were euthanized, and plasma samples and tumors collected. Tumor tissue was homogenized, extracted and analyzed using liquid chromatography-QTOF-MS, capillary electrophoresis-TOF-MS and gas chromatography-EI-Q-MS. Differences between groups were evaluated by unpaired t-test or Mann−Whitney test with post hoc Benjamini-Hochberg correction. Statistical significance was set at P≤0.05. Compound identification was accomplished using online databases and in-house standards

Results Tumor volume increased in vehicle-treated mice by ~700%, 142 ± 8 mm3 to 957 ± 79 mm3 and only ~250% in MNF-treated mice, 143 ± 8 mm3 to 259 ± 27 mm3. On Day 33, MNF was not detected in plasma but accumulated in tumor tissues, 43.9 ± 32.7 ng/g. Plasma L-lactate levels were reduced from 3.29 ± 0.66 mmol/L το 2.81 ± 0.60 mmol/L, P≤0.001. Differences in tumor tissue metabolome were observed with MNF compared to vehicle, which was reflected by significant, P≤0.05, changes in relative metabolite signals. MNF treatment was accompanied by the disruption of pyrimidine nucleotide biosynthesis at uridine 5'-monophosphate, UMP, and increased UMP degradation. Moreover, the +237% increase in ophthalmic acid and +95% increase in its precursor 2-aminobutyrate indicate higher oxidative stress and the +51% increase in 2-hydroxyproline suggest greater HFI-1α proteolysis upon MNF treatment.

Conclusions These results are consistent with our previous observations in PANC-1 cells showing that GPR55 inhibition attenuates activation of the EGFR-MEK-ERK, Wnt-β-catenin and PI3K/AKT pathways resulting in lower cyclin D1 expression and halting the cell cycle in G1. The reduction in HIF-1α expression and glycolytic flux in MNF-treated PANC-1 cells is in line with the decline in L-lactate plasma levels in MNF-treated mice. The data from this study indicate that MNF may be useful in the treatment of pancreatic cancer.

Citation Format: Irving W. Wainer, Danuta Dudzik, Michel Bernier, Coral Barbas. Multiplatform metabolomics analysis of growth arrest in pancreatic tumor xenografts [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5055. doi:10.1158/1538-7445.AM2017-5055

A review of blood sample handling and pre-processing for metabolomics studies

Metabolomics has been found to be applicable to a wide range of clinical studies, bringing a new era for improving clinical diagnostics, early disease detection, therapy prediction and treatment efficiency monitoring. A major challenge in metabolomics, particularly untargeted studies, is the extremely diverse and complex nature of biological specimens. Despite great advances in the field there still exist fundamental needs for considering pre-analytical variability that can introduce bias to the subsequent analytical process and decrease the reliability of the results and moreover confound final research outcomes. Many researchers are mainly focused on the instrumental aspects of the biomarker discovery process, and sample related variables sometimes seem to be overlooked. To bridge the gap, critical information and standardized protocols regarding experimental design and sample handling and pre-processing are highly desired. Characterization of a range variation among sample collection methods is necessary to prevent results misinterpretation and to ensure that observed differences are not due to an experimental bias caused by inconsistencies in sample processing. Herein, a systematic discussion of pre-analytical variables affecting metabolomics studies based on blood derived samples is performed. Furthermore, we provide a set of recommendations concerning experimental design, collection, pre-processing procedures and storage conditions as a practical review that can guide and serve for the standardization of protocols and reduction of undesirable variation.

GC-MS based Gestational Diabetes Mellitus longitudinal study: Identification of 2-and 3-hydroxybutyrate as potential prognostic biomarkers

Gestational Diabetes Mellitus (GDM) causes severe short- and long-term complications for the mother, fetus and neonate, including type 2-diabetes (T2DM) later in life. In this pilot study, GC-Q/MS analysis was applied for plasma metabolomics fingerprinting of 24 healthy and 24 women with GDM at different stages of gestation (second and third trimester) and postpartum (one and three months). Multivariate (unsupervised and supervised) statistical analysis was performed to investigate variance in the data, identify outliers and for unbiased assessment of data quality. Plasma fingerprints allowed for the discrimination of GDM pregnant women from controls both in the 2nd and 3rd trimesters of gestation. However, metabolic profiles tended to be similar after delivery. Follow up of these women revealed that 4 of them developed T2DM within 2 years postpartum. Multivariate PLS-DA models limited to women with GDM showed clear separation 3 months postpartum. In the 2nd trimester of gestation there was also a clear separation between GDM women that were normoglycemic after pregnancy and those with recognized postpartum T2DM. Metabolites that had the strongest discriminative power between these groups in the 2nd trimester of gestation were 2-hydroxybutyrate, 3-hydroxybutyrate, and stearic acid. We have described, that early GDM comprises metabotypes that are associated with the risk of future complications, including postpartum T2DM. In this pilot study, we provide evidence that 2-hydroxybutyrate and 3-hydroxybutyrate may be considered as future prognostic biomarkers to predict the onset of diabetic complications in women with gestational diabetes after delivery.

New Biochemical Insights into the Mechanisms of Pulmonary Arterial Hypertension in Humans

Diagnosis of pulmonary arterial hypertension (PAH) is difficult due to the lack of specific clinical symptoms and biomarkers, especially at early stages. We compared plasma metabolic fingerprints of PAH patients (n = 20) with matched healthy volunteers (n = 20) using, for the first time, untargeted multiplatform metabolomics approach consisting of high-performance liquid and gas chromatography coupled with mass spectrometry. Multivariate statistical analyses were performed to select metabolites that contribute most to groups’ classification (21 from liquid in both ionization modes and 9 from gas chromatography-mass spectrometry). We found metabolites related to energy imbalance, such as glycolysis-derived metabolites, as well as metabolites involved in fatty acid, lipid and amino acid metabolism. We observed statistically significant changes in threitol and aminomalonic acid in PAH patients, which could provide new biochemical insights into the pathogenesis of the disease. The results were externally validated on independent case and control cohorts, confirming up to 16 metabolites as statistically significant in the validation study. Multiplatform metabolomics, followed by multivariate chemometric data analysis has a huge potential for explaining pathogenesis of PAH and for searching potential and new more specific and less invasive markers of the disease.

Differential amniotic fluid cytokine profile in women with chorioamnionitis with and without funisitis

OBJECTIVES

To evaluate whether the amniotic fluid (AF) cytokine profile in women with chorioamnionitis may differentiate between those with and without funisitis.

SUBJECTS AND METHODS

Forty women at high risk of chorioamnionitis were studied. Gestational age at study was 26.94. Amniocentesis, universal and specific polymerase chain reaction, and microbiological cultures were performed. AF IL-1β, IL-2, IL-4, IL-6, IL 8, IL-10, IL-12, TNF-alpha, IFN-gamma, and MMP-8 were measured by multiplex assay. After delivery, the placenta and umbilical cord were studied histologically. Comparisons were made between three groups: controls, and chorioamnionitis with and without funisitis.

RESULTS

In 25 cases, the histological findings were normal (61.5%). The remaining 15 composed of 9 cases of chorioamnionitis alone (9/40; 23.1%) and 6 cases of chorioamnionitis plus funisitis (6/40; 15.4%). All AF cytokine levels were significantly higher in the cases with chorioamnionitis in comparison to controls, except for IFN-gamma. The comparisons between the three groups showed significant differences between chorioamnionitis alone and chorioamnionitis plus funisitis in IL-1β, IL-6, IL-10, IL-12, IL-8, and TNF-alpha, with the levels being higher when funisitis was present. Logistic regression found a powerful predictive model for funisitis including the following cytokinesIL-4, IL-10, IL-12, and IL-8.

CONCLUSIONS

Measurements of AF interleukins 4, 10, 12, and 8 allow to identify cases with funisitisin women at high risk of chorioamnionitis.

Optimization and validation of a chiral GC-MS method for the determination of free D-amino acids ratio in human urine: application to a gestational diabetes mellitus study

Gestational Diabetes Mellitus (GDM) is defined as glucose intolerance with onset or first recognition during pregnancy. It is affecting approximately up to 14% of all pregnancies with an increasing tendency. GDM has been related to relevant short-term and long-term health complications for both mother and offspring. Recent studies strongly emphasized the role of several essential amino acids in the pathogenesis of obesity and highlighted their strong correlation with insulin resistance, but there are no references related to modifications in D-AAs in biological fluids. As D-AA elimination proceeds mainly by renal excretion, urine was the selected sample to evaluate the alterations in free D-AAs ratio in a GDM study. Only 1 mL of first void urine or standard solution was required for purification, by using a Discovery DSC-SCX SPE cartridge (500 mg/3 mL) and derivatization into their N(O)-pentafluoropropionyl amino acid 2-propyl esters. Enantiomeric separation was carried out by GC-MS on a Chirasil-L-Val N-propionyl-L-valine-tert-butylamide polysiloxane fused-silica capillary column (25 m×0.25 mm I.D., 0.12 μm film thickness, Agilent Technologies, Waldbronn, Germany), under programmed temperature elution. Detection was performed with an ion trap mass analyzer, operating in the full scan mode in the m/z 50-350 range. 14 pairs of derivatives of D-and L-AAs were separated. The steps of sample preparation, derivatization and GC-MS conditions were optimized for both urine and standards. Several conditions affecting the SPE procedure, such as sorbent mass/volume ratio of the cartridge, sample dilution and pH, were optimized. Volume of reagents and solvents and reaction temperature and time were also tested for the derivatization. Regarding the GC-MS parameters, split ratio, temperature program and mass range were optimized. The final method was validated in terms of linearity, sensitivity, accuracy and precision for D-Ala, D-Pro, D-Ser, D-Met, D-Phe, D-Glu, D-Orn and D-Lys. Identification of AAs in urine samples was based on retention time and mass spectra. Urine from 20 women with GDM and 20 pregnant women with normal glucose tolerance (after 2-h 75-g oral glucose tolerance test), matched according to the week of gestation and age (22-28 week of gestation and age 24-37 years), were enrolled into the study. %D-Relative amounts were determined for Ala, Val, Thr, Ser, Leu, Asx (Asp+Asn), Glx (Glu+Gln), Met, Phe, Tyr, Orn and Lys. Statistically significant differences (p<0.05) were observed only for D-Phe and higher values were found in the GDM group. It is possible that D-Phe could be involved in metabolic/signaling pathways to compensate early stages of insulin resistance, although further work is necessary to confirm this hypothesis.

Metabolic fingerprint of Gestational Diabetes Mellitus

Gestational Diabetes (GDM) is causing severe short- and long-term complications for mother, fetus or neonate. As yet, the metabolic alterations that are specific for the development of GDM have not been fully determined, which also precludes the early diagnosis and prognosis of this pathology. In this pilot study, we determine the metabolic fingerprint, using a multiplatform LC-QTOF/MS, GC-Q/MS and CE-TOF/MS system, of plasma and urine samples of 20 women with GDM and 20 with normal glucose tolerance in the second trimester of pregnancy. Plasma fingerprints allowed for the discrimination of GDM pregnant women from controls. In particular, lysoglycerophospholipids showed a close association with the glycemic state of the women. In addition, we identified some metabolites with a strong discriminative power, such as LPE(20:1), (20:2), (22:4); LPC(18:2), (20:4), (20:5); LPI(18:2), (20:4); LPS(20:0) and LPA(18:2), as well as taurine-bile acids and long-chain polyunsaturated fatty acid derivatives. Finally, we provide evidence for the implication of these compounds in metabolic routes, indicative of low-grade inflammation and altered redox-balance, that may be related with the specific pathophysiological context of the genesis of GDM. This highlights their potential use as prognostic markers for the identification of women at risk to develop severe glucose intolerance during pregnancy.

BIOLOGICAL SIGNIFICANCE

Gestational Diabetes Mellitus (GDM) is increasing worldwide and, although diabetes usually remits after pregnancy, women with GDM have a high risk of developing postpartum type 2-diabetes, particularly when accompanied by obesity. Therefore, understanding the pathophysiology of GDM, as well as the identification of potentially modifiable risk factors and early diagnostic markers for GDM are relevant issues. In the present study, we devised a multiplatform metabolic fingerprinting approach to obtain a comprehensive picture of the early metabolic alternations that occur in GDM, and may reflect on the specific pathophysiological context of the disease. Future studies at later stages of gestation will allow us to validate the discriminant power of the identified metabolites.

Differences and similarities between LC-MS derived serum fingerprints of patients with B-cell malignancies

Multiple myeloma (MM) and chronic lymphocytic leukaemia (CLL) are closely related B-cell non-Hodgkin’s lymphomas. MM, a plasma cell malignancy, is the second most common haematopoietic cancer in Western countries, with the median survival time of 3–4 years. CLL, a lymphocyte B malignancy, is the most common leukaemia in Western countries. About 25–30% of all CLL patients do not survive the period of 5 years following diagnosis. Both malignancies are complicated, not fully understood and incurable with the current standard treatment. Biologically, MM and CLL may be preceded by associated precursor conditions, that is, monoclonal gammopathy of undetermined significance for MM and its cellular counterpart and monoclonal B-cell lymphocytosis for CLL. Similarities and differences in the biology of these malignancies prompted us to evaluate their metabolomics in stages requiring chemotherapy. Fingerprinting of serum metabolites by the use of LC-MS has never been applied in studies on MM and CLL patients. Obtained results revealed metabolites common for both malignancies (e.g. fatty acids, acylcarnitines, sphingolipids, phospholipids, phenylalanylphenylalanine and isoprene) as well as those which render them different (e.g. lysophosphatidylcholines, monoacylglycerols, aminocaproic acid, phenylacetylglutamine).

Colon cancer releases alpha-tocopherol from its O-glycosides better than normal colon tissue

BACKGROUND/AIMS

Free radicals, in a colon, may damage DNA, make difficult DNA repair and change course of post-translational modifications of regulatory proteins, which promote tumor initiation and progression. Therefore risk of colon cancer is closely related to diet and other lifestyle factors. Dietary antioxidants, such as vitamin E, should reduce the levels of harmful oxidation products. However vitamin E is not soluble in water, which decreases its bioavailability. As O-glycosides of alpha-tocopherol are better soluble in water and penetrate to tissues easier than free alpha-tocopherol, the aim of our work was to investigate the rate of release the free tocopherol from its O-glycosides in colon cancer, in comparison to human healthy colon tissue.

METHODOLOGY

The activities of enzymes catalysing hydrolysis of alpha-tocopheryl glucoside (1a) and mannoside (1b) as well as p-nitrophenyl beta-glucoside (2a) and mannoside (2b) in cancer and healthy human colon tissues, were determined according to the modified method described by Zwierz et al.

RESULTS

The alpha-tocopherol and p-nitrophenol were significantly better released from the respective glucosides and mannosides in cancer tissue than in "healthy" human colon tissues, with p = 0.000947 for la, p = 0.033024 for 1b; p = 0.0028 for 2a, and p = 0.0033 for 2b, respectively.

CONCLUSION

Alpha-tocopherol and p-nitrophenol are released from the O-glycosides of glucose and mannose in significantly higher amount in colon cancer than in healthy tissues. The alpha-tocopherol O-glycosides can be considered as prodrugs in prevention and treatment of the colon cancer.

Decomposition of α-Tocopheryl Glycosides in Rat Tissues

Background

The aim of our investigation was to estimate the stability of α-tocopheryl O-glycosides in relation to activity of exoglycosidases in selected rat tissues.

Material and Methods

Acetylated glycosides were obtained in glucosidation of α-tocopherol using the Helferich method. The activity of exoglycosidases was determined by the Zwierz et al. method. Protein concentrations were determined by the biuret method. The concentration of released α-tocopherol was determined with the HPLC method.

Results

The comparison of the amount of released α-tocopherol with the amount of released p-nitrophenol shows that glycoside bound in 2a–5a derivatives of α-tocopherol undergoes hydrolysis significantly harder than in appropriate 2b–5bp-nitrophenyl derivatives.

Conclusion

The results indicate that tocopheryl O-glycosides are more resistant to enzymatic hydrolysis than appropriate p-nitrophenol O-glycosides 2a–5a. Among examined tocopheryl O-glycosides, galactoside 4 is the only compound that caused the significant increase in tocopherol concentration, as compared to its endogenic content.

Fucosylation in synovial fluid as a novel clinical marker for differentiating joint diseases--a preliminary study

OBJECTIVE

To investigate fucosylation of synovial fluid glycoproteins in patients with rheumatoid arthritis (RA), juvenile arthritis (JIA), gonarthrosis (GA) and reactive arthritis (ReA), referred to traumatized knee (TK).

METHODS

Synovial fluid glycoproteins were separated by SDS-PAGE and either silver stained or blotted onto nitrocellulose and probed with the fucose-specific Aleuria aurantia lectin. Five bands were chosen for densitometric analysis. Total fucose content and density of fucosylated epitopes were analyzed.

RESULTS

Fucose content was elevated in all patient groups and almost all bands, comparing to TK. The density of fucosylated epitopes was increased in the 42-kDa band of RA and JIA cases, and lowered in the 26-kDa band of RA and JIA, but not in GA. In all RA cases FR 42-kDa > FR 26-kDa. The relation was opposite in 8 out of 9 GA cases.

CONCLUSION

The density of fucosylated epitopes differs significantly in particular glycoproteins of synovial fluid in joint diseases and may be of potential diagnostic value in differentiating diseases of inflammatory and degenerative origin.

Activity of lysosomal exoglycosidases in saliva of patients with HIV infection

PURPOSE

The aim of this work was to evaluate the influence of HIV infection on the catabolism of glycoconjugates in the oral cavity, by determination of the activity of lysosomal exoglycosidases in mixed saliva.

METHOD

The specific activities of the following exoglycosidases were tested: N-acetyl-beta-hexosaminidase (HEX), its isoenzymes A (HEX-A) and B (HEX-B), alpha-mannosidase (MAN), beta-galactosidase (GAL) and alpha-fucosidase (FUC).

RESULT

A significant increase of activity of HEX-A, GAL and FUC, and a significant decrease of the activity of HEX-B was found, but no significant changes in the HEX and MAN activity we noted.

CONCLUSION

Our results indicate that following HIV infection, there is probably an increased rate of catabolism of glycoconjugates in saliva resulting from changes in the proportions of the activity of isoenzymes A and B of N-acetyl-beta-hexosaminidase, beta-galactosidase and alpha-fucosidase. An increase of HEXA activity can implicate the beginning of neoplastic changes developing in the oral cavity.

Saliva of patients with Type 1 diabetes: effect of smoking on activity of lysosomal exoglycosidases

OBJECTIVE

The aim of our study was to evaluate the influence of smoking on the activity of N-acetyl-beta-hexosaminidase (HEX), its isoenzymes A (HEX-A) and B (HEX-B) and beta-galactosidase (GAL), in the saliva of patients with Type 1 diabetes.

METHODS

In the supernatant HEX and its isoenzymes A and B, and beta-galactosidase were determined by the method of Chatteriee et al in modification of Zwierz et al (mKat kg(-1) of protein). Protein was determined by the Lowry et al method (mg ml(-1)).

RESULTS

The results presented here suggest that diabetes and smoking modify activity of HEX and its isoenzymes, but only combination of diabetes and smoking give a significant increase in the specific activity of HEX and its isoenzymes.

CONCLUSIONS

Type 1 diabetes slightly changes the composition of saliva. Smoking cigarettes significantly modifies the composition and properties of saliva in healthy individuals and patients with Type 1 diabetes.

The cleavage of vitamin E galactoside in the rat tissue homogenates

The stability of alpha-tocopheryl beta-galactoside in the presence of endogenous galactosidases in selected tissue homogenates (liver, kidney, ileum and brain) was estimated. High degree release of alpha-tocopherol from alpha-tocopheryl beta-galactoside in tissues of ileum, kidney and brain was observed (82%, 75% and 72%, increase above endogenous alpha-tocopherol, respectively). A possible enzymatic mechanism of the galactoside decomposition was proposed.

Development of ocular mucin: scanning EM analysis

Ocular mucin (mucus) development in the mouse was examined using several different fixatives and scanning electron microscopy. One of the fixatives, a picric acid--paraformaldehyde-glutaraldehyde (PA-P-G) preparation which fixes mucin at the adult mouse corneal surface, first demonstrated mucin at the surface of the pup cornea and conjunctiva at postnatal day 10. The mucus was scant, strand-like as well as granular in morphology and did not form smooth patches as in the adult. Thus, mucin is present at the ocular surface well before the mouse eye opens (day 14-15). Its presence is essential to ensure tear film stability, corneal wettability and possibly to protect the eye from bacterial and viral insult.