Analytical methods and biomonitoring results in hair for the assessment of exposure to endocrine-disrupting chemicals: A literature review.

Endocrine-disrupting chemicals (EDC) are compounds that alter functions of the endocrine system due to their ability to mimic or antagonize endogenous hormones, or that alter their synthesis and metabolism, causing adverse health effects. Human biomonitoring (HBM) is a reliable method to assess human exposure to chemicals through measurement in human body fluids and tissues. It identifies new sources of exposure and determines their distribution, thereby enabling detection of the most exposed populations. Blood and urine are commonly used for HBM of EDC, but their interest is limited for compounds presenting short half-lives. Hair appears as an interesting alternative insofar as it provides a large exposure window. For the present study, we evaluated the relevance of hair in determining EDC exposure. With this in mind, we undertook a literature review focusing on the bioanalytical aspects and performances of methods developed to determine EDC in hair. The literature review was performed through methodical bibliographical research. Relevant articles were identified using two scientific databases: PubMed and Web of Science, with search equations built from a combination of keywords, MeSH terms and Boolean operators. The search strategy identified 2949 articles. After duplicates were removed, and following title, abstract, and full-text screenings, only 31 were included for qualitative synthesis. Hair collection was mainly performed in the back of the head and preparation involved two processes: cutting into small pieces or grounding to powder. The off-line LC-MS/MS method remains the main technique used to assess EDC through hair. Differences regarding the validation of analytical methods and interpretation of HBM results were highlighted, suggesting a need for international harmonisation to obtain reliable and comparable results. External contamination of hair was identified as a main limitation in the interpretation of results, highlighting the need to better understand EDC transfers through hair and to develop relevant hair decontamination processes.

Assessment of Endocrine Disruptor Exposure in Hospital Professionals Using Hair and Urine Analyses: An Awareness Campaign.

BACKGROUND: In 2021, French public authorities initiated the fourth National Environmental Health Plan to prevent environment-related health risks. This plan primarily focuses on the sensitization of health professionals and health care institutions. Endocrine disruptors (EDs) are environmental factors associated with several adverse health effects, such as reproductive disorders, obesity, and cancer. This study aimed to conduct an awareness campaign among professionals at a general hospital center on the risks related to EDs. METHODS: Hospital professionals were directly involved in this study, and urine and hair samples were collected to determine bisphenol and paraben exposure levels. Analyses were performed using validated liquid chromatography-tandem mass spectrometry methods, enabling the simultaneous determination of bisphenols and parabens. A questionnaire on lifestyle habits was distributed to assess its relationship with the exposure profiles. Nineteen professionals were recruited for the study. RESULTS: Bisphenol A was detected in 95% of the urine samples, and the chlorinated derivatives of bisphenol A were between 16% and 63%. parabens showed detection frequencies between 37% and 100%, and methylparaben was quantified at an average concentration of 0.45 ± 0.46 ng/mL. In hair samples, bisphenols A, F, and S were detected at 95%-100%, chlorinated derivatives of bisphenol A were detected at 37%-68%, and parabens were detected at 100%. CONCLUSIONS: This awareness campaign may encourage health care institutions to adopt a policy of reducing endocrine disruptor exposure among their patients and professionals, who could be educated regarding the risks associated with EDs. Conducting a multicenter study to refine the results herein and establish a dynamic to prevent endocrine disruptor and environmental risks in health care systems would be valuable.

Analytical method for the biomonitoring of bisphenols and parabens by liquid chromatography coupled to tandem mass spectrometry in human hair.

Bisphenols and parabens are endocrine disruptors families widely used in daily life. They are known to be linked to numerous pathologies such as reproductive disorders, obesity, breast cancer, hypertension and asthma. Biomonitoring is an essential tool for assessing population exposure to environmental pollutants. Blood and urine are the main matrices used in human biomonitoring. However, they are not suitable to evaluate long-term exposure to endocrine disruptors with a short elimination half-life such as parabens or phenols. Hair appears to be an interesting alternative matrix allowing a wide window of exposure due to an accumulation of xenobiotics during hair growth. This study presents the development and validation of a high-performance liquid chromatography coupled to tandem mass spectrometry for the simultaneous determination of bisphenol A, its chlorinated derivatives, bisphenol F, bisphenol S and parabens in human hair. An optimised sample preparation based on acidic hydrolysis followed by liquid-liquid extraction was performed, before an analysis by ultra-high performance liquid chromatography coupled to tandem mass spectrometry in multiple reaction monitoring mode. To validate the method, recognized bioanalytical guidelines were used and calibration and quality control samples were prepared in human hair samples. Linearities were over 0.996 in the whole range of concentrations. Trueness and precision were demonstrated for each target analyte with intra-day and inter-day bias values ranging from 86 % to 118 % and relative standard deviation values ranging from 0 % to 19 %. At the same time, limits of quantification were set at 0.25 ng/g for bisphenol A and parabens, 0.05 ng/g for bisphenols F and S and 0.00625 ng/g for the chlorinated derivatives of bisphenol A. This reliable method was applied to hair samples taken from hospital professionals and allowed the quantification of these endocrine disruptors in this population. Chlorinated derivatives of bisphenol A were quantified here in hair for the first time.

Identification of a crucial amino acid implicated in the hydroxylation/desaturation ratio of CpFAH12 bifunctional hydroxylase.

Claviceps purpurea bifunctional Δ12-hydroxylase/desaturase, CpFAH12, and monofunctional desaturase CpFAD2, share 86% of sequence identity. To identify the underlying determinants of the hydroxylation/desaturation specificity, chimeras of these two enzymes were tested for their fatty acid production in an engineered Yarrowia lipolytica strain. It reveals that transmembrane helices are not involved in the hydroxylation/desaturation specificity whereas all cytosolic domains have an impact on it. Especially, replacing the CpFAH12 cytosolic part near the second histidine-box by the corresponding CpFAD2 part annihilates all hydroxylation activity. Further mutagenesis experiments within this domain identified isoleucine 198 as the crucial element for the hydroxylation activity of CpFAH12. Monofunctional variants performing the only desaturation were obtained when this position was exchanged by the threonine of CpFAD2. Saturation mutagenesis at this position showed modulation in the hydroxylation/desaturation specificity in the different variants. The WT enzyme was demonstrated as the most efficient for ricinoleic acid production and some variants showed a better desaturation activity. A model based on the recently discovered membrane desaturase structures indicate that these changes in specificity are more likely due to modifications in the di-iron center geometry rather than changes in the substrate binding mode.

Development and validation of an LC-MS/MS method for the simultaneous determination of bisphenol A and its chlorinated derivatives in adipose tissue.

Bisphenol A (BPA) and its chlorinated derivatives (Clx-BPA) are environmental pollutants exhibiting endocrine-disrupting (ED) properties suspected to be involved in the pathogenesis of hormone-dependent cancers, such as breast and prostate cancers. Due to their lipophilic properties, they may accumulate in adipose tissue which could therefore be a suitable matrix to assess long-term exposure to these compounds and relationships with the tumorigenesis of these cancers. An LC-MS/MS assay for the determination of BPA and Clx-BPA in adipose tissue samples was developed and fully validated according to current bioanalytical validation guidelines. Ionization was achieved using an electrospray source operating in the negative mode and quantification of target analytes was obtained in the multiple reaction monitoring mode. Both standard and quality control (QC) samples were prepared in blank adipose tissue samples. Linearity was demonstrated over the ranges 0.125 to 8.000 and 0.0125-0.8000 ng/mL for BPA and Clx-BPA, respectively. Accuracy and precision were demonstrated over the whole concentration range: intra and inter-day bias values were in the 85-114% range and imprecision of the method did not exceed 14%. Lower limits of quantification were validated using QCs at 0.1250 and 0.0125 ng/mL for BPA and Clx-BPA, respectively. Internal standard-corrected matrix effects were comparable in breast and prostate adipose tissues, demonstrating that this method could be used to reliably assay BPA and Clx-BPA in both tissues. The method was sensitive enough to determine BPA and Clx-BPA in breast adipose tissue obtained from women undergoing breast surgery, enabling identification of different patterns of exposure to these ED chemicals. The method enables the reliable quantification of BPA and Clx-BPA in adipose tissue and could be used to assess long-term exposure to these compounds and potential associations with hormone-dependent cancers.

Developing cellulolytic Yarrowia lipolytica as a platform for the production of valuable products in consolidated bioprocessing of cellulose.

BACKGROUND: Both industrial biotechnology and the use of cellulosic biomass as feedstock for the manufacture of various commercial goods are prominent features of the bioeconomy. In previous work, with the aim of developing a consolidated bioprocess for cellulose bioconversion, we conferred cellulolytic activity of Yarrowia lipolytica, one of the most widely studied "nonconventional" oleaginous yeast species. However, further engineering this strain often leads to the loss of previously introduced heterologous genes due to the presence of multiple LoxP sites when using Cre-recombinase to remove previously employed selection markers. RESULTS: In the present study, we first optimized the strategy of expression of multiple cellulases and rescued selection makers to obtain an auxotrophic cellulolytic Y. lipolytica strain. Then we pursued the quest, exemplifying how this cellulolytic Y. lipolytica strain can be used as a CBP platform for the production of target products. Our results reveal that overexpression of SCD1 gene, encoding stearoyl-CoA desaturase, and DGA1, encoding acyl-CoA:diacylglycerol acyltransferase, confers the obese phenotype to the cellulolytic Y. lipolytica. When grown in batch conditions and minimal medium, the resulting strain consumed 12 g/L cellulose and accumulated 14% (dry cell weight) lipids. Further enhancement of lipid production was achieved either by the addition of glucose or by enhancing cellulose consumption using a commercial cellulase cocktail. Regarding the latter option, although the addition of external cellulases is contrary to the concept of CBP, the amount of commercial cocktail used remained 50% lower than that used in a conventional process (i.e., without internalized production of cellulases). The introduction of the LIP2 gene into cellulolytic Y. lipolytica led to the production of a strain capable of producing lipase 2 while growing on cellulose. Remarkably, when the strain was grown on glucose, the expression of six cellulases did not alter the level of lipase production. When grown in batch conditions on cellulose, the engineered strain consumed 16 g/L cellulose and produced 9.0 U/mL lipase over a 96-h period. The lipase yield was 562 U lipase/g cellulose, which represents 60% of that obtained on glucose. Finally, expression of the hydroxylase from Claviceps purpurea (CpFAH12) in cellulolytic Y. lipolytica procured a strain that can produce ricinoleic acid (RA). Using this strain in batch cultures revealed that the consumption of 11 g/L cellulose sustained the production of 2.2 g/L RA in the decane phase, 69% of what was obtained on glucose. CONCLUSIONS: In summary, this study has further demonstrated the potential of cellulolytic Y. lipolytica as a microbial platform for the bioconversion of cellulose into target products. Its ability to be used in consolidated process designs has been exemplified and clues revealing how cellulose consumption can be further enhanced using commercial cellulolytic cocktails are provided.

Distillate-range products from non-oil-based sources by catalytic cascade reactions.

An original two-step process efficiently catalyzed by functionalized mesoporous materials is proposed as a potential route for converting light olefins into long-chain hydrocarbons in the distillate range. In the first step, ethylene can be selectively transformed into C4 -C10 olefins with an even number of carbon atoms, over nickel-exchanged AlMCM-41, at 150 °C. When the nickel-catalyzed oligomerization was assisted by a second acid-catalyzed step over H-MCM-41, olefins with chains longer than 10 carbon atoms were mainly produced with a productivity of 180 g g⁻¹ h⁻¹.