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- Gauthier, Marie-Soleil, et al.
(author)
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The Metabolically Healthy But Obese Phenotype Is Associated With Lower Plasma Levels of Persistent Organic Pollutants as Compared to the Metabolically Abnormal Obese Phenotype
- 2014
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In: Journal of Clinical Endocrinology and Metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 99:6, s. E1061-E1066
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Journal article (peer-reviewed)abstract
- Context: Although obesity is strongly linked to insulin resistance and type 2 diabetes, a subset of obese individuals termed metabolically healthy but obese(MHO) appears relatively protected from the development of cardiometabolic complications. The origins of this metabolically healthy phenotype remain unclear. Recently, persistent organic pollutants (POPs) have emerged as potential endocrine disruptors.Objective: The aim of this study was to test the hypothesis that the MHO phenotype presents lower circulating levels of POPs as compared to the metabolically abnormal obese (MAO) phenotype.Design, Setting, and Patients: We conducted a cross-sectional study of 76 nondiabetic obese (body mass index >= 30 kg/m(2)) postmenopausal women.Main Outcome Measures: Plasma concentrations of 21 POPs as well as cardiometabolic risk factors were analyzed.Results: For similar age, body mass index, and fat mass index, MHO women (n = 40) showed higher insulin sensitivity levels and a more favorable cardiometabolic profile than MAO women (n = 36), as evidenced by a 2-fold increase in glucose disposal rates measured by the hyperinsulinemic-euglycemic clamp (P = .001). Among 18 detectable pollutants measured, MAO women had higher plasma concentrations of 12 POPs (fold increase, 1.4-2.9; P < .001-.036). Logistic regression analyses showed that the prevalence of the MAO phenotype was significantly associated with higher levels of total dioxin and non-dioxin-like polychlorinated biphenyls (odds ratio, 4.7; 95% confidence interval, 1.8-12.5; P = .002), as well as trans-nonachlor (odds ratio, 6.1; 95% CI, 2.2-16.4; P < .001).Conclusion: Our study demonstrates that the metabolically healthy and abnormal phenotypes have distinct plasma POP profiles.
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- Geng, Dawei, 1986-, et al.
(author)
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Analysis of brominated flame retardants and their derivatives by atmospheric pressure chemical ionization using gas chromatography coupled to tandem quadrupole mass spectrometry
- 2017
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In: Talanta. - Amsterdam, Netherlands : Elsevier. - 0039-9140 .- 1873-3573. ; 162, s. 618-624
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Journal article (peer-reviewed)abstract
- A validated method using an atmospheric pressure chemical ionization source for coupling gas chromatography (GC-APCI) to tandem quadrupole mass spectrometry (MS/MS) for the determination of brominated flame retardants (BFRs) is presented. Polybrominated diphenyl ethers (PBDEs), their methoxylated derivatives (MeO-PBDEs) and other emerging BFRs were included in this study. The method showed good linearity and repeatability. The relative standard deviation (RSD) of the relative response factors (RRFs) of all compounds was less than 16%. Repeatability for BFRs was tested on one or two concentration levels of calibration standardswith RSDs for RRFs below 16%. The lowest calibration standards (0.075 –0.1 pg/μL for emerging BFRs, BDE 209 and MeO-PBDEs mixtures, 0.625 –6.25 pg/μL for Br1-9 PBDEs mixtures) were used as instrument detection limits (IDL). The method was applied on biotic samples, including fish, osprey, and seal. In general, BDE209 and decabromodiphenyl ethane (DBDPE) were detected in 50% of the seal samples. A 100% detection rate was achieved for 6-MeO-BDE47 in all the samples (72 –580 pg/g ww in osprey samples, 24 000 –96 000 pg/g ww in seal samples and 78–99 pg/g ww in fish samples). AllBr3-6PBDEs (BDE28, 47, 99, 100, 153, 154) were detected in all the samples (ranging from 12 to 20 000 pg/g ww), while BDE183 was detected in 60% of the osprey eggs, 20% of the seal samples and below MDL in all fish samples. The results presented indicate the capability of the GC-APCI-MS/MS system for the detection and quantification of BFRs.
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| 7. |
- Geng, Dawei, 1986-, et al.
(author)
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Effect of perfluorooctanesulfonic acid (PFOS) on the liver lipid metabolism of the developing chicken embryo
- 2019
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In: Ecotoxicology and Environmental Safety. - : Elsevier. - 0147-6513 .- 1090-2414. ; 170, s. 691-698
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Journal article (peer-reviewed)abstract
- Perfluorooctanesulfonate (PFOS) is a well-known contaminant in the environment and it has shown to disrupt multiple biological pathways, particularly those related with lipid metabolism. In this study, we have studied the impact of in ovo exposure to PFOS on lipid metabolism in livers in developing chicken embryos using lipidomics for detailed characterization of the liver lipidome. We used an avian model (Gallus gallus domesticus) for in ovo treatment at two levels of PFOS. The lipid profile of the liver of the embryo was investigated by ultra-high performance liquid chromatography combined with quadrupole-time-of-flight mass spectrometry and by gas chromatography mass spectrometry. Over 170 lipids were identified, covering phospholipids, ceramides, di- and triacylglycerols, cholesterol esters and fatty acid composition of the lipids. The PFOS exposure caused dose dependent changes in the lipid levels, which included upregulation of specific phospholipids associated with the phosphatidylethanolamine N-methyltransferase (PEMT) pathway, triacylglycerols with low carbon number and double bond count as well as of lipotoxic ceramides and diacylglycerols. Our data suggest that at lower levels of exposure, mitochondrial fatty acid β-oxidation is suppressed while the peroxisomal fatty acid β -oxidation is increased. At higher doses, however, both β -oxidation pathways are upregulated.
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| 8. |
- Geng, Dawei, 1986-, et al.
(author)
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Gas chromatography/atmospheric pressure chemical ionization/mass spectrometry for the analysis of organochlorine pesticides and polychlorinated biphenyls in human serum
- 2016
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In: Journal of Chromatography A. - Amsterdam, Netherlands : Elsevier. - 0021-9673 .- 1873-3778. ; 1453, s. 88-98
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Journal article (peer-reviewed)abstract
- A method using a novel atmospheric pressure chemical ionization source for coupling gas chromatography (GC/APCI) to triple quadrupole mass spectrometry (MS/MS) for the determination of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) regulated by the Stockholm Convention is presented. One microliter injection of a six-point calibration curve of native PCBs and OCPs, ranging from 0.04 to 300 pg/μL, was performed. The relative standard deviation (RSD) of the relative response factors (RRFs) was less than 15% with a coefficient of determination (r2) >0.995. Meanwhile, two calibration solutions (CS), CS 2 (0.4 pg/μL) and CS 3 (4 pg/μL) were analyzed to study the repeatability calculated for both area and RRFs. The RSD for RRF ranged from 3.1 to 16% and 3.6 to 5.5% for CS 2 and CS 3, respectively. The limits of detection (LOD) determined by peak-to-peak signal-to-noise ratio (S/N) of 3 were compared between the GC/APCI/MS/MS and a GC coupled to high resolution mass spectrometry (GC/HRMS) system. GC/APCI/MS/MS resulted in lower LOD for most of the compounds, except for PCB#74, cis-chlordane and trans-chlordane. GC/APCI/MS/MS and GC/HRMS were also compared by performing analysis on 75 human serum samples together with eight QA/QC serum samples. The comparison between GC/APCI/MS/MS system and GC/HRMS system for 16 of the targeted compounds was carried out. No statistically significant difference was discovered. Due to increased sensitivity and user friendly operation under atmospheric pressure, GC/APCI/MS/MS is a powerful alternative technique that can easily meet the specification of GC/HRMS.
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| 9. |
- Geng, Dawei, 1986-
(author)
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Gas chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry methods for the determination of environmental contaminants
- 2016
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Doctoral thesis (other academic/artistic)abstract
- The recent developments and improvements of instrumental methods for the analyses of the environmental contaminants, especially the persistent organic pollutants (POPs), have made it possible to detect and quantify these at very low concentrations in environmental and biotic matrices.The main objective of this thesis is to demonstrate the capability of the atmospheric pressure chemical ionization technique (APCI), using gas chromatography coupled to tandem mass spectrometry for the determination of a wide range of environmental contaminants, including the POPs regulated by Stockholm Convention, such as polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), but also the derivates of PBDEs and novel brominated flame retardants (NBFRs).The APCI was operated in charge transfer condition, preferably producing molecular ions. Multiple reaction monitoring (MRM) experiments were optimized by adjusting cone voltage, collision energy and dwell time. Optimization of source parameters, such as gas flows and temperatures was also performed. Low concentration standards were analyzed, achieving a visible chromatographic peak for 2 fg 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) demonstrating the excellent sensitivity of the system. Adequate linearity and repeatability were observed for all the studied compounds. The performance of APCI methods was validated against the conventional methods using gas chromatography coupled to high resolution mass spectrometry for chlorinated compounds in a wide range of matrices including environmental, air, human and food matrices.The GC-APCI-MS/MS method was successfully applied to a set of 75 human serum samples to study the circulating levels of POPs in epidemiologic studies. Moreover the method was utilized to establish temporal trends of POPs in osprey eggs samples collected during the past five decades.
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