Glutamine/glutamate metabolism rewiring in reprogrammed human hepatocyte-like cells.

Human dermal fibroblasts can be reprogrammed into hepatocyte-like (HEP-L) cells by the expression of a set of transcription factors. Yet, the metabolic rewiring suffered by reprogrammed fibroblasts remains largely unknown. Here we report, using stable isotope-resolved metabolic analysis in combination with metabolomic-lipidomic approaches that HEP-L cells mirrors glutamine/glutamate metabolism in primary cultured human hepatocytes that is very different from parental human fibroblasts. HEP-L cells diverge glutamine from multiple metabolic pathways into deamidation and glutamate secretion, just like periportal hepatocytes do. Exceptionally, glutamine contribution to lipogenic acetyl-CoA through reductive carboxylation is increased in HEP-L cells, recapitulating that of primary cultured human hepatocytes. These changes can be explained by transcriptomic rearrangements of genes involved in glutamine/glutamate metabolism. Although metabolic changes in HEP-L cells are in line with reprogramming towards the hepatocyte lineage, our conclusions are limited by the fact that HEP-L cells generated do not display a complete mature phenotype. Nevertheless, our findings are the first to characterize metabolic adaptation in HEP-L cells that could ultimately be targeted to improve fibroblasts direct reprogramming to HEP-L cells.

Monitoring of system conditioning after blank injections in untargeted UPLC-MS metabolomic analysis.

Ultra-performance liquid chromatography - mass spectrometry (UPLC-MS) is widely used for untargeted metabolomics in biomedical research. To optimize the quality and precision of UPLC-MS metabolomic analysis, evaluation of blank samples for the elimination of background features is required. Although blanks are usually run either at the beginning or at the end of a sequence of samples, a systematic analysis of their effect of the instrument performance has not been properly documented. Using the analysis of two common bio-fluids (plasma and urine), we describe how the injection of blank samples within a sequence of samples may affect both the chromatographic and MS detection performance depending on several factors, including the sample matrix and the physicochemical properties of the metabolites of interest. The analysis of blanks and post-blank conditioning samples using t-tests, PCA and guided-PCA provides useful information for the elimination of background UPLC-MS features, the identification of column carry over and the selection of the number of samples required to achieve a stable performance.

Determination of aniline and quinoline compounds in textiles.

A simple method for simultaneous determination of twenty-one analytes, belonging to two classes of compounds, aromatic amines and quinolines, is presented. Several of the analytes considered in this study frequently occur in textiles goods on the open market and have been related to allergic contact dermatitis and/or are proven or suspected carcinogens. The method includes an efficient clean-up step using graphitized carbon black (GCB) that simplifies and improves the robustness of the subsequent GC-MS analysis. Briefly, after solvent extraction of the textile sample, the extract is passed through a GCB SPE cartridge that selectively retain dyes and other interfering compounds present in the matrix, producing a clean extract, suitable for GC-MS analysis, is obtained. The method was evaluated by spiking blank textiles with the selected analytes. Method quantification limits (MQL) ranged from 5 to 720ng/g depending on the analyte. The linear range of the calibration curves ranged over two order magnitude with coefficients of determination (R2) higher than 0.99. Recoveries ranged from 70 to 92% with RSDs 1.7-14%. The effectiveness of the method was tested on a variety of textile materials samples from different origin. In a pilot explorative survey, 2,6-dichloro-4-nitroaniline was detected in all the analysed clothing samples in concentrations ranging from 1.0 to 576µg/g. 2,4-dinitroaniline was detected in four of the seven samples with a highest concentration of 305µg/g. Quinoline was detected in all samples in concentrations ranging from 0.06 to 6.2µg/g.

The washout effect during laundry on benzothiazole, benzotriazole, quinoline, and their derivatives in clothing textiles.

In two previous papers, the authors have shown that benzothiazole, benzotriazole, quinoline, and several of their derivatives are widespread in clothing textile articles. A number of these compounds exhibit allergenic and irritating properties and, due to their octanol-water partition coefficient, are prone to be absorbed by the skin. Moreover, they are slightly soluble in water, which could make washing of clothes a route of emission into the environment. In the present study, the washout effect of benzothiazole, benzotriazole, quinoline, and some of their derivatives has been investigated. Twenty-seven textile samples were analyzed before, as well as after five and ten times of washing. The most abundant analyte was found to be benzothiazole, which was detected in 85 % of the samples with an average concentration of 0.53 µg/g (median 0.44 µg/g), followed by quinoline, detected in 81 % of the samples with an average concentration of 2.42 µg/g (median 0.21 µg/g). The average decrease in concentration for benzothiazoles was 50 % after ten times washing, while it was around 20 % for quinolines. The average emission to household wastewater of benzothiazoles and quinolines during one washing (5 kg of clothes made from polyester materials) was calculated to 0.5 and 0.24 g, respectively. These results strongly indicate that laundering of clothing textiles can be an important source of release of these compounds to household wastewater and in the end to aquatic environments. It also demonstrates a potential source of human exposure to these chemicals since considerable amounts of the compounds remain in the clothes even after ten times of washing.

Benzothiazole, benzotriazole, and their derivates in clothing textiles--a potential source of environmental pollutants and human exposure.

Textiles play an important role in our daily life, and textile production is one of the oldest industries. In the manufacturing chain from natural and/or synthetic fibers to the final clothing products, the use of many different chemicals is ubiquitous. A lot of research has focused on chemicals in textile wastewater, but the knowledge of the actual content of harmful chemicals in clothes sold on the retail market is limited. In this paper, we have focused on eight benzothiazole and benzotriazole derivatives, compounds rated as high production volume chemicals. Twenty-six clothing samples of various textile materials and colors manufactured in 14 different countries were analyzed in textile clothing using liquid chromatography tandem mass spectrometry. Among the investigated textile products, 11 clothes were for babies, toddlers, and children. Eight of the 11 compounds included in the investigation were detected in the textiles. Benzothiazole was present in 23 of 26 investigated garments in concentrations ranging from 0.45 to 51 µg/g textile. The garment with the highest concentration of benzothiazole contained a total amount of 8.3 mg of the chemical. The third highest concentration of benzothiazole (22 µg/g) was detected in a baby body made from "organic cotton" equipped with the "Nordic Ecolabel" ("Svanenmärkt"). It was also found that concentrations of benzothiazoles in general were much higher than those for benzotriazoles. This study implicates that clothing textiles can be a possible route for human exposure to harmful chemicals by skin contact, as well as being a potential source of environmental pollutants via laundering and release to household wastewater.

Quinolines in clothing textiles--a source of human exposure and wastewater pollution?

A production process in which the use of various types of chemicals seems to be ubiquitous makes the textile industry a growing problem regarding both public health as well as the environment. Among several substances used at each stage, the present study focuses on the quinolines, a class of compounds involved in the manufacture of dyes, some of which are skin irritants and/or classified as probable human carcinogens. A method was developed for the determination of quinoline derivatives in textile materials comprising ultrasound-assisted solvent extraction, solid phase extraction cleanup, and final analysis by gas chromatography/mass spectrometry. Quinoline and ten quinoline derivatives were determined in 31 textile samples. The clothing samples, diverse in color, material, brand, country of manufacture, and price, and intended for a broad market, were purchased from different shops in Stockholm, Sweden. Quinoline, a possible human carcinogen, was found to be the most abundant compound present in almost all of the samples investigated, reaching a level of 1.9 mg in a single garment, and it was found that quinoline and its derivatives were mainly correlated to polyester material. This study points out the importance of screening textiles with nontarget analysis to investigate the presence of chemicals in an unbiased manner. Focus should be primarily on clothing worn close to the body.

Organophosphate and phthalate esters in standard reference material 2585 organic contaminants in house dust.

The levels of 22 phthalate diesters (phthalates) and organophosphate triesters (organophosphates) have been investigated in standard reference material 2585 (SRM 2585) "organic contaminants in house dust." Ultrasonic-assisted solvent extraction and solid-phase extraction on a Florisil adsorbent were used as the extraction and cleanup steps combined with analysis using gas chromatography-tandem mass spectrometry in positive ion chemical ionization mode. Seven phthalates were detected in the concentration range 1-570 µg/g. Di(2-ethylhexyl) phthalate was the major phthalate present at 570 µg/g. Ten organophosphates were detected in SRM 2585. Tris(2-butoxyethyl) phosphate was the predominant organophosphate at 82 µg/g, and nine organophosphates were determined at concentrations ranging from 0.19 to 2.3 µg/g. Five organophosphates were below the method detection limit, of which two were in level with the procedural blank. The applied extraction and cleanup method was evaluated for the analysis of SRM 2585. The extraction yield was ≥99%, except for tris(2-chloroethyl) phosphate (97%) and diethyl phthalate (98.5%). The problem of calibration curvature is addressed, and it is shown that the use of deuterated standards improves the analysis. The concentrations of ten organophosphate esters were determined in SRM 2585, and seven of these were compared with existing data. To our knowledge, this is the first report of the levels of the seven phthalates esters in SRM 2585 "organic contaminants in house dust."