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Wu AH, Franke AA, Wilkens LR, Tseng C, Conroy SM, Li Y, Polfus LM, De Rouen M, Caberto C, Haiman C, Stram DO, Le Marchand L, Cheng I. Urinary phthalate exposures and risk of breast cancer: the Multiethnic Cohort study. Breast Cancer Res 2021; 23:44. [PMID: 33823904 PMCID: PMC8025373 DOI: 10.1186/s13058-021-01419-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 03/15/2021] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND The epidemiologic evidence from observational studies on breast cancer risk and phthalates, endocrine disrupting chemicals, has been inconsistent. In the only previous study based on pre-diagnostic urinary phthalates and risk of breast cancer, results were null in mostly white women. METHODS We examined the association between pre-diagnostic urinary phthalates and breast cancer in a nested case-control study within the Multiethnic Cohort (MEC) study, presenting the first data from five major racial/ethnic groups in the USA. We measured 10 phthalate metabolites and phthalic acid, using a sensitive liquid chromatography mass spectrometry assay on 1032 women with breast cancer (48 African Americans, 77 Latinos, 155 Native Hawaiians, 478 Japanese Americans, and 274 Whites) and 1030 matched controls. Conditional logistic regression was used to examine risk with individual metabolites and ratios of primary (MEHP, mono-2-ethylhexyl-phthalate) to secondary (MEHHP, mono(2-ethyl-5-hydroxyhexyl); MEOHP, mono(2-ethyl-5-oxohexy)) metabolites of di-2-ethylhexyl phthalate (DEHP), a widely used plasticizer. In addition, we investigated risk associations with high (∑HMWP) and low molecular weight (∑LMWP) phthalates, as well as total phthalates which included high and low molecular weight phthalates with phthalic acid (∑LMHMPA) or without phthalic acid in molar ratios (∑LMHMmolar) and adjusted for creatinine and potential confounders. RESULTS Among all women, breast cancer risk was higher for those in tertile 2 and tertile 3 of primary to secondary metabolites of DEHP (MEHP/(MEHHP + MEOHP)) in comparison to those in tertile 1; the respective odds ratios were 1.32 (95% CI 1.04-1.68) and 1.26 (95% CI 0.96-1.66) (Ptrend = 0.05). Risk among Native Hawaiian women increased with exposures to eight of ten individual phthalates and total phthalates (∑LMHMPA ORT3 vs T1 = 2.66, 95% CI 1.39-5.12, Ptrend = 0.001). In analysis by hormone receptor (HR) status, exposure above the median of ∑LMWP was associated with an increased risk of HR-positive breast cancer (OR = 1.30, 95% CI 1.05-1.60) while above the median exposure to phthalic acid was associated with an increased risk of HR-negative breast cancer (ORabove vs below median = 1.59, 95% CI 1.01-2.48). CONCLUSIONS Further investigations of suggestive associations of elevated breast cancer risk with higher ratios of primary to secondary metabolites of DEHP, and differences in risk patterns by race/ethnicity and HR status are warranted.
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Affiliation(s)
- Anna H. Wu
- grid.42505.360000 0001 2156 6853Department of Preventive Medicine, University of Southern California Keck School of Medicine, 1441 Eastlake Avenue, Rm 4443, Los Angeles, CA 90089 USA
| | - Adrian A. Franke
- grid.410445.00000 0001 2188 0957University of Hawaii Cancer Center, Honolulu, HI USA
| | - Lynne R. Wilkens
- grid.410445.00000 0001 2188 0957University of Hawaii Cancer Center, Honolulu, HI USA
| | - Chiuchen Tseng
- grid.42505.360000 0001 2156 6853Department of Preventive Medicine, University of Southern California Keck School of Medicine, 1441 Eastlake Avenue, Rm 4443, Los Angeles, CA 90089 USA
| | - Shannon M. Conroy
- grid.27860.3b0000 0004 1936 9684Department of Public Health Sciences, School of Medicine, University of California, Davis, Davis, CA USA
| | - Yuqing Li
- grid.266102.10000 0001 2297 6811Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA USA
| | - Linda M. Polfus
- grid.42505.360000 0001 2156 6853Department of Preventive Medicine, University of Southern California Keck School of Medicine, 1441 Eastlake Avenue, Rm 4443, Los Angeles, CA 90089 USA ,grid.42505.360000 0001 2156 6853Center for Genetic Epidemiology, University of Southern California, Los Angeles, CA USA
| | - Mindy De Rouen
- grid.266102.10000 0001 2297 6811Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA USA
| | - Christian Caberto
- grid.410445.00000 0001 2188 0957University of Hawaii Cancer Center, Honolulu, HI USA
| | - Christopher Haiman
- grid.42505.360000 0001 2156 6853Department of Preventive Medicine, University of Southern California Keck School of Medicine, 1441 Eastlake Avenue, Rm 4443, Los Angeles, CA 90089 USA ,grid.42505.360000 0001 2156 6853Center for Genetic Epidemiology, University of Southern California, Los Angeles, CA USA
| | - Daniel O. Stram
- grid.42505.360000 0001 2156 6853Department of Preventive Medicine, University of Southern California Keck School of Medicine, 1441 Eastlake Avenue, Rm 4443, Los Angeles, CA 90089 USA
| | - Loïc Le Marchand
- grid.410445.00000 0001 2188 0957University of Hawaii Cancer Center, Honolulu, HI USA
| | - Iona Cheng
- grid.266102.10000 0001 2297 6811Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA USA
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Liu L, Wang Z, Zhao S, Duan J, Tao H, Wang W, Liu S. Determination of total phthalate in cosmetics using a simple three-phase sample preparation method. Anal Bioanal Chem 2017; 410:1323-1331. [DOI: 10.1007/s00216-017-0774-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2017] [Revised: 10/30/2017] [Accepted: 11/20/2017] [Indexed: 11/24/2022]
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Xie Q, Sun D, Han Y, Jia L, Hou B, Liu S, Li D. Determination of total phthalates in edible oils by high-performance liquid chromatography coupled with photodiode array detection. J Sep Sci 2016; 39:857-63. [DOI: 10.1002/jssc.201501169] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2015] [Revised: 12/14/2015] [Accepted: 12/14/2015] [Indexed: 11/10/2022]
Affiliation(s)
- Qilong Xie
- State Key Laboratory of Coal Conversion, Institute of Coal Chemistry; Chinese Academy of Sciences; Taiyuan Shanxi China
| | - Dekui Sun
- State Key Laboratory of Coal Conversion, Institute of Coal Chemistry; Chinese Academy of Sciences; Taiyuan Shanxi China
| | - Yangying Han
- College of Science; Northwest A&F University; Yangling Shaanxi China
| | - Litao Jia
- State Key Laboratory of Coal Conversion, Institute of Coal Chemistry; Chinese Academy of Sciences; Taiyuan Shanxi China
| | - Bo Hou
- State Key Laboratory of Coal Conversion, Institute of Coal Chemistry; Chinese Academy of Sciences; Taiyuan Shanxi China
| | - Shuhui Liu
- College of Science; Northwest A&F University; Yangling Shaanxi China
| | - Debao Li
- State Key Laboratory of Coal Conversion, Institute of Coal Chemistry; Chinese Academy of Sciences; Taiyuan Shanxi China
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Liu S, Liu L, Han Y, Sun J, Feng J, Wang J, Zhong C. Rapid screening of edible oils for phthalates using phase-transfer catalyst-assisted hydrolysis and liquid phase microextraction coupled to high performance liquid chromatography–tandem mass spectrometry. J Chromatogr A 2015; 1420:26-34. [DOI: 10.1016/j.chroma.2015.10.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Revised: 09/30/2015] [Accepted: 10/01/2015] [Indexed: 10/23/2022]
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Murphy CJ, Stermer AR, Richburg JH. Age- and species-dependent infiltration of macrophages into the testis of rats and mice exposed to mono-(2-Ethylhexyl) phthalate (MEHP). Biol Reprod 2014; 91:18. [PMID: 24876407 DOI: 10.1095/biolreprod.113.115527] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The mechanism by which noninfectious testicular inflammation results in infertility is poorly understood. Here the infiltration of CD11b+ immunoreactive testicular interstitial cells (neutrophil, macrophages, dendritic cells) in immature (Postnatal Day [PND] 21, 28, and 35) and adult (PND 56) Fischer rats is described at 12, 24, and 48 h after an oral dose of 1 g/kg mono-(2-ethylhexyl) phthalate (MEHP), a well-described Sertoli cell toxicant. Increases of CD11b+ cells are evident 12 h after MEHP exposure in PND 21 and 28 rats. In PND 28 rats, CD11b+ cells remained significantly elevated at 48 h, while in PND 21 rats, it returned to control levels by 24 h. The peak number of CD11b+ cells in PND 35 rat testis is delayed until 24 h, but remains significantly elevated at 48 h. In PND 56 rats, no increase in CD11b+ cells occurs after MEHP exposure. In PND 21, 28, and 35 rats, a significant increase in monocyte chemoattractant protein-1 (MCP-1) by peritubular myoid cells occurs 12 h after MEHP. Interestingly, MEHP treatment of C57BL/6J mice did not incite an infiltration of CD11b+ cells at either PND 21 or 28. The peak level of germ cell apoptosis observed 24 h after MEHP exposure in young rats is not seen in mice at any age or in PND 56 rats. Taken together, these findings implicate MCP-1 released by peritubular myoid cells in provoking the migration of CD11b+ cells into the immature rat testis early after MEHP exposure and point to a role for CD11b+ cells in triggering germ cell apoptosis in an age- and species-dependent manner.
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Affiliation(s)
- Caitlin J Murphy
- Center for Molecular and Cellular Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, Texas
| | - Angela R Stermer
- Center for Molecular and Cellular Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, Texas
| | - John H Richburg
- Center for Molecular and Cellular Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, Texas
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Bang DY, Lee IK, Lee BM. Toxicological characterization of phthalic Acid. Toxicol Res 2013; 27:191-203. [PMID: 24278572 PMCID: PMC3834394 DOI: 10.5487/tr.2011.27.4.191] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2011] [Revised: 10/15/2011] [Accepted: 10/25/2011] [Indexed: 11/20/2022] Open
Abstract
There has been growing concern about the toxicity of phthalate esters. Phthalate esters are being used widely for the production of perfume, nail varnish, hairsprays and other personal/cosmetic uses. Recently, exposure to phthalates has been assessed by analyzing urine for their metabolites. The parent phthalate is rapidly metabolized to its monoester (the active metabolite) and also glucuronidated, then excreted. The objective of this study is to evaluate the toxicity of phthalic acid (PA), which is the final common metabolic form of phthalic acid esters (PAEs). The individual PA isomers are extensively employed in the synthesis of synthetic agents, for example isophthalic acid (IPA), and terephthalic acid (TPA), which have very broad applications in the preparation of phthalate ester plasticizers and components of polyester fiber, film and fabricated items. There is a broad potential for exposure by industrial workers during the manufacturing process and by the general public (via vehicle exhausts, consumer products, etc). This review suggests that PA shows in vitro and in vivo toxicity (mutagenicity, developmental toxicity, reproductive toxicity, etc.). In addition, PA seems to be a useful biomarker for multiple exposure to PAEs in humans.
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Affiliation(s)
- Du Yeon Bang
- Laboratory of Toxicology, College of Pharmacy, Sungkyunkwan University, Suwon 440-746, Korea
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Feng XL, Lu SY, Liu D, Li L, Wu XZ, Song J, Hu P, Li YS, Tang F, Li ZH, Wang GM, Zhou Y, Liu ZS, Ren HL. Direct competitive immunosorbent assay for detection of MEHP in human urine. CHEMOSPHERE 2013; 92:150-155. [PMID: 23561568 DOI: 10.1016/j.chemosphere.2013.02.062] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2012] [Revised: 01/20/2013] [Accepted: 02/17/2013] [Indexed: 06/02/2023]
Abstract
Di-(2-ethylhexyl) phthalate (DEHP) is the most commonly used plasticizer for flexible polyvinyl chloride (PVC), which is also known as one of the environmental endocrine disruptors with the reproductive, developmental and embryonic toxicity after entering human body. Mono-2-ethylhexyl phthalate (MEHP) is one of the most complicate metabolites from DEHP in vivo and responsible for many toxic effects of DEHP. In order to evaluate human exposure to DEHP, a direct competitive enzyme-linked immunosorbent (dcELISA) based on monoclonal antibody (mAb) was developed to detect MEHP. A hybridoma cell line 4B9 secreting mAb against MEHP was prepared, and the horseradish peroxidase (HRP) labeled antigen as a probe in the dcELISA was made. After optimization of ELISA reaction conditions, the standard curve with a linear range from 0.56 to 1000 ng mL(-1) and a detection limit of 0.39 ng mL(-1) was established. The cross-reactivities of anti-MEHP mAb to other ten phthalate esters were less than 5% except for mono-methylphthalate (MME). The average recoveries of MEHP from distilled water and negative human urine were both between 87.4% and 94.72% with coefficient of variation (CV) less than 5%. Here, the ELISA method on detecting MEHP was successfully established and applied to real urine sample analyses and the results were confirmed by HPLC. Furthermore, it was indicated that the immunoassay was reliable and suitable for monitoring MEHP.
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Affiliation(s)
- Xiao-Li Feng
- Key Laboratory of Zoonosis Research, Ministry of Education, Institute of Zoonosis, College of Animal Science and Veterinary Medicine, Jilin University, Changchun 130062, PR China
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Berthet A, Berode M, Bouchard M. Gas-chromatography mass-spectrometry determination of phthalic acid in human urine as a biomarker of folpet exposure. Anal Bioanal Chem 2011; 400:493-502. [DOI: 10.1007/s00216-011-4753-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Revised: 01/27/2011] [Accepted: 02/01/2011] [Indexed: 11/29/2022]
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10
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Ostrovský I, Čabala R, Kubinec R, Górová R, Blaško J, Kubincová J, Řimnáčová L, Lorenz W. Determination of phthalate sum in fatty food by gas chromatography. Food Chem 2011. [DOI: 10.1016/j.foodchem.2010.06.045] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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11
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Palaeophytochemical Constituents from the Miocene-fossil Wood of Picea likiangensis in Xun-dian of Yunnan, China. B KOREAN CHEM SOC 2008. [DOI: 10.5012/bkcs.2008.29.8.1613] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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12
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Simultaneous Gas Chromatography-Mass Spectrometric Determination of Total and Individual Phthalic Esters Utilizing Alkaline Hydrolysis and Silyl Derivatization Technique. B KOREAN CHEM SOC 2007. [DOI: 10.5012/bkcs.2007.28.3.432] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Vermeulen R, Jönsson BAG, Lindh CH, Kromhout H. Biological monitoring of carbon disulphide and phthalate exposure in the contemporary rubber industry. Int Arch Occup Environ Health 2005; 78:663-9. [PMID: 16041606 DOI: 10.1007/s00420-005-0017-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2004] [Accepted: 06/01/2005] [Indexed: 10/25/2022]
Abstract
OBJECTIVES We studied the range in urinary levels of 2-thiothiazolidine-4-carboxyl acid (TTCA), a metabolite of CS2 and phthalic acid (PA), a common metabolite of phthalates, across factories and departments in the contemporary rubber manufacturing industry. METHODS Spot urine samples from 101 rubber workers employed in nine different factories were collected on Sunday and during the workweek on Tuesday, Wednesday and Thursday at approximately 4 pm. In total, 386 urine samples were successfully analyzed. RESULTS Levels of both biomarkers increased significantly by a factor 2 (paired t-test P-value <0.05) during the working week as compared to the Sunday biomarker levels with absolute increases of approximately 70 microg/l and 5 micromol/mol creatinine for PA and TTCA, respectively. Levels in both biomarkers did not differ markedly between working days. Increases seemed to be restricted to specific factories and/or departments (e.g. molding and curing). CONCLUSIONS The results of this study demonstrate that rubber workers in the contemporary rubber industry are exposed to phthalates and low levels of CS2 ( approximately 0.05 ppm) as measured by PA and TTCA, respectively. Exposures to both compounds are largely driven by specific circumstances in factories. Therefore, when estimating exposures to phthalates and CS2 detailed information should be collected on the type and amount of phthalate containing ester plasticizers, dithiocarbamates and thiurams used. Preferably, personal exposure data should be collected. In this case, biological monitoring seems a reasonable approach. However, in the case of PA attention should be given to individual background levels as this could lead to a substantial overestimation of the occupational contribution to total phthalate exposure.
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Affiliation(s)
- Roel Vermeulen
- Division of Cancer Epidemiology and Genetics, Occupational and Environmental Epidemiology Branch, National Cancer Institute, NIH, DHHS, 6120 Executive Boulevard, Rockville, MD 20852, USA.
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Koch HM, Rossbach B, Drexler H, Angerer J. Internal exposure of the general population to DEHP and other phthalates--determination of secondary and primary phthalate monoester metabolites in urine. ENVIRONMENTAL RESEARCH 2003; 93:177-185. [PMID: 12963402 DOI: 10.1016/s0013-9351(03)00083-5] [Citation(s) in RCA: 185] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A number of phthalates and their metabolites are suspected of having teratogenic and endocrine disrupting effects. Especially the developmental and reproductive effects of di(2-ethylhexyl)phthalate (DEHP) are under scrutiny. In this study we determined the concentrations of the secondary, chain oxidized monoester metabolites of DEHP, mono(2-ethyl-5-hydroxyhexyl)phthalate (5OH-MEHP) and mono(2-ethyl-5-oxo-hexyl)phthalate (5oxo-MEHP) in urine samples from the general population. The utilization of the secondary metabolites minimized any risk of contamination by the ubiquitously present phthalate parent compounds. Included in the method were also the simple monoester metabolites of DEHP, dioctylphthalate (DOP), di-n-butylphthalate (DnBuP), butylbenzylphthalate (BBzP) and diethylphthalate (DEP). Automated sample preparation was performed applying a column switching liquid chromatography system enabling online extraction of the urine on a restricted access material (RAM) and separation on a reversed phase analytical column. Detection was performed by negative ESI-tandem mass spectrometry in multiple reaction monitoring mode and quantification by isotope dilution. The excretion of DEHP and the other phthalates was studied by analyzing first morning urine samples from 53 women and 32 men aged 7-64 years (median: 34.2 years) living in northern Bavaria (Germany) who were not occupationally exposed to phthalates. Phthalate metabolites, secondary and primary ones, were detected in all specimens. Concentrations were found to vary strongly from phthalate to phthalate and subject to subject with differences spanning more than three orders of magnitude. Median concentrations for excretion of DEHP metabolites were 46.8 microg/L for 5OH-MEHP (range 0.5-818 microg/L), 36.5 microg/L for 5oxo-MEHP (range 0.5-544 microg/L), and 10.3 microg/L for MEHP (range:<0.5 (limit of quantification, LOQ) to 177 microg/L). A strong correlation was found between the excretion of 5OH-MEHP and 5oxo-MEHP with a correlation coefficient of r=0.991, indicating close metabolic proximity of those two parameters but also the absence of any contaminating interference. Median concentrations for the other monoester metabolites were for mono-n-butylphthalate (MnBuP) 181 microg/L, for monobenzylphthalate (MBzP) 21.0 microg/L, for monoethylphthalate (MEP) 90.2 microg/L and for mono-n-octylphthalate (MOP)<1.0 microg/L (LOQ). These results will help to perform health risk assessments for the phthalate exposure of the general population.
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Affiliation(s)
- Holger M Koch
- Institute and Outpatient Clinic of Occupational, Social and Environmental Medicine, University of Erlangen-Nuremberg, Schillerstrasse 25/29, Erlangen D-91054, Germany
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Silva MJ, Malek NA, Hodge CC, Reidy JA, Kato K, Barr DB, Needham LL, Brock JW. Improved quantitative detection of 11 urinary phthalate metabolites in humans using liquid chromatography-atmospheric pressure chemical ionization tandem mass spectrometry. J Chromatogr B Analyt Technol Biomed Life Sci 2003; 789:393-404. [PMID: 12742130 DOI: 10.1016/s1570-0232(03)00164-8] [Citation(s) in RCA: 128] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Phthalates are widely used as industrial solvents and plasticizers, with global use exceeding four million tons per year. We improved our previously developed high-performance liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometric (HPLC-APCI-MS/MS) method to measure urinary phthalate metabolites by increasing the selectivity and the sensitivity by better resolving them from the solvent front, adding three more phthalate metabolites, monomethyl phthalate (mMP), mono-(2-ethyl-5-oxohexyl)phthalate (mEOHP) and mono-(2-ethyl-5-hydroxyhexyl)phthalate (mEHHP); increasing the sample throughput; and reducing the solvent usage. Furthermore, this improved method enabled us to analyze free un-conjugated mono-2-ethylhexyl phthalate (mEHP) by eliminating interferences derived from coelution of the glucuronide-bound, or conjugated form, of the mEHP on measurements of the free mEHP. This method for measuring phthalate metabolites in urine involves solid-phase extraction followed by reversed-phase HPLC-APCI-MS/MS using isotope dilution with (13)C(4) internal standards. We further evaluated the ruggedness and the reliability of the method by comparing measurements made by multiple analysts at different extraction settings on multiple instruments. We observed mMP, monoethyl phthalate (mEP), mono-n-butyl phthalate (mBP), monobenzyl phthalate (mBzP), mEHP, mEHHP and mEOHP in the majority of urine specimens analyzed with DEHP-metabolites mEHHP and mEOHP present in significantly higher amounts than mEHP.
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Affiliation(s)
- Manori J Silva
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, 4770 Buford Hwy NE, Mailstop F17, Atlanta, GA 30341-3724, USA.
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Gazouli M, Yao ZX, Boujrad N, Corton JC, Culty M, Papadopoulos V. Effect of peroxisome proliferators on Leydig cell peripheral-type benzodiazepine receptor gene expression, hormone-stimulated cholesterol transport, and steroidogenesis: role of the peroxisome proliferator-activator receptor alpha. Endocrinology 2002; 143:2571-83. [PMID: 12072389 DOI: 10.1210/endo.143.7.8895] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In this study, we hypothesized that many of the reported effects of phthalate esters and other peroxisome proliferators (PPs) in the testis are mediated by members of the PP- activated receptor (PPAR) family of transcription factors through alterations in proteins involved in steroidogenesis. Exposure of Leydig cells to PPs prevented cholesterol transport into the mitochondria after hormonal stimulation and inhibited steroid synthesis, without altering total cell protein synthesis or mitochondrial and DNA integrity. PPs also reduced the levels of the cholesterol-binding protein peripheral-type benzodiazepine receptor (PBR) because of a direct transcriptional inhibition of PBR gene expression in MA-10 Leydig cells. MA-10 cells contain mRNAs for PPARalpha and PPARbeta/delta, but not for PPARgamma. In vivo treatment of mice with PPs resulted in the reduction of both testis PBR mRNA and circulating testosterone levels, in agreement with the proposed role of PBR in steroidogenesis. By contrast, liver PBR mRNA levels were increased, in agreement with the proposed role of PBR in cell growth/tumor formation in nonsteroidogenic tissues. However, PPs did not inhibit testosterone production and testis PBR expression in PPARalpha-null mice. These results suggest that the antiandrogenic effect of PPs is mediated by a PPARalpha-dependent inhibition of Leydig cell PBR gene expression.
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MESH Headings
- Androgen Antagonists
- Animals
- Biological Transport, Active/drug effects
- Blotting, Northern
- Carrier Proteins/biosynthesis
- Carrier Proteins/genetics
- Catalase/metabolism
- Cell Survival/drug effects
- Cells, Cultured
- Cholesterol/metabolism
- Chorionic Gonadotropin/antagonists & inhibitors
- DNA Damage/drug effects
- Electrophoresis, Polyacrylamide Gel
- Gene Expression Regulation/drug effects
- Humans
- Leydig Cells/drug effects
- Leydig Cells/metabolism
- Male
- Mice
- Mitochondria/drug effects
- Mitochondria/metabolism
- Pancreatic Elastase
- Peroxisome Proliferators/pharmacology
- RNA, Messenger/biosynthesis
- Radioimmunoassay
- Radioligand Assay
- Rats
- Receptors, Cytoplasmic and Nuclear/drug effects
- Receptors, Cytoplasmic and Nuclear/metabolism
- Receptors, GABA-A/biosynthesis
- Receptors, GABA-A/drug effects
- Receptors, GABA-A/genetics
- Reverse Transcriptase Polymerase Chain Reaction
- Steroids/biosynthesis
- Transcription Factors/drug effects
- Transcription Factors/metabolism
- Transfection
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Affiliation(s)
- Maria Gazouli
- Division of Hormone Research, Department of Cell Biology, Georgetown University Medical Center, Washington, DC 20007, USA
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Blount BC, Milgram KE, Silva MJ, Malek NA, Reidy JA, Needham LL, Brock JW. Quantitative detection of eight phthalate metabolites in human urine using HPLC-APCI-MS/MS. Anal Chem 2000; 72:4127-34. [PMID: 10994974 DOI: 10.1021/ac000422r] [Citation(s) in RCA: 246] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Because of the ubiquity of phthalates and their potential role in increasing risk for cancer and reproductive dysfunction, the need for human exposure assessment studies is urgent. In response to this need, we developed a high-throughput, robust, sensitive, accurate, and precise assay for simultaneous measurement of trace levels of eight phthalate metabolites in human urine by HPLC-MS/MS. Human urine samples were processed using enzymatic deconjugation of the glucuronides followed by solid-phase extraction. The eluate was concentrated, and the phthalate metabolites were chromatographically resolved by reversed-phase HPLC, detected by APCI-tandem mass spectrometry, and quantified by isotope dilution. This selective analytical method permits rapid detection (7.7 min total run time) of eight urinary metabolites of the most commonly used phthalates with detection limits in the low nanagram per milliliter range. Assay precision was improved by incorporating 13C4-labeled internal standards for each of the eight analytes, as well as a conjugated internal standard to monitor deconjugation efficiency. This selective, sensitive, and rapid method will help elucidate potential associations (if any) between human exposure to phthalates and adverse health effects.
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Affiliation(s)
- B C Blount
- Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, Georgia 30341, USA
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Richburg JH, Nañez A, Gao H. Participation of the Fas-signaling system in the initiation of germ cell apoptosis in young rat testes after exposure to mono-(2-ethylhexyl) phthalate. Toxicol Appl Pharmacol 1999; 160:271-8. [PMID: 10544061 DOI: 10.1006/taap.1999.8786] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The Fas-signaling system is composed of the interacting proteins Fas (CD95/APO-1) and Fas ligand (FasL, CD95L, APO-1L) and is proposed to act in the testis as a paracrine signaling mechanism by which FasL-expressing Sertoli cells initiate apoptosis of Fas-bearing germ cells. Here we describe alterations in the expression of Fas and FasL in the testis after the intimate physical association between Sertoli cells and germ cells is disrupted by exposure to the Sertoli cell toxicant mono-2-(ethylhexyl) phthalate (MEHP). Young, 28-day-old Fisher rats were treated with MEHP (2 g/kg po) and killed 0, 3, 6, and 12 h after exposure. Immunohistochemical analyses revealed a significant increase in the numbers of Fas-positive germ cells as well as increases in the expression of Sertoli cell FasL. Western blot analysis demonstrated a time-dependent increase in the production of the soluble form of FasL after MEHP exposure and suggests that it may participate in triggering apoptosis in germ cells that have lost their intimate association with the Sertoli cells. Measurement of Fas in cytosolic and membrane fractions of testis homogenates by Western blot analysis revealed a significant shift of Fas expression into the membrane fraction after MEHP exposure. Taken together, these observations indicate that the Fas-mediated paracrine signaling mechanism participates in triggering apoptosis of germ cells despite the loss of their close physical association with Sertoli cells. A working model is presented to explain the involvement of the Fas-system in stimulating germ cell apoptosis after MEHP exposure.
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Affiliation(s)
- J H Richburg
- College of Pharmacy, The University of Texas at Austin, Austin, Texas, 78712-1074, USA.
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Albro PW, Corbett JT, Schroeder JL. The metabolism of di(2-ethylhexyl)phthalate in the earthworm Lumbricus terrestris. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. C, COMPARATIVE PHARMACOLOGY AND TOXICOLOGY 1993; 104:335-44. [PMID: 8098688 DOI: 10.1016/0742-8413(93)90045-m] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
1. Earthworms can hydrolyze di-(2-ethylhexyl) phthalate (DEHP) to mono-2-ethylhexyl phthalate (MEHP) and phthalic acid (PA). 2. They apparently cannot produce the side-chain-oxidized derivatives of MEHP that constitute the major DEHP metabolites in higher animals. 3. With the assistance of intestinal bacterial Pseudomonas, the worm-derived PA is degraded through protocatechuic and beta-carboxymuconic acids to CO2. 4. There is an indication of a second pathway for degradation of PA leading through benzoic acid.
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Affiliation(s)
- P W Albro
- Laboratory of Molecular Biophysics, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709
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Albro PW, Corbett JT, Schroeder J, Reddy JK. Beta-oxidation of 2-ethyl-5-carboxypentyl phthalate in rodent liver. BIOCHIMICA ET BIOPHYSICA ACTA 1987; 923:196-205. [PMID: 3814613 DOI: 10.1016/0304-4165(87)90004-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
[7-14C]-2-Ethyl-5-carboxypentyl phthalate was isolated and purified from urine of rats given [7-14C]-di-(2-ethylhexyl) phthalate. This metabolite was shown to serve as a precursor for 2-ethyl-3-carboxypropyl phthalate in vivo. 2-Ethyl-5-carboxypentyl phthalate was oxidized to 2-ethyl-3-carboxypropyl phthalate in liver slices from control or, much more rapidly, from clofibrate-pretreated rats. Inhibition by KCN in liver slices from untreated rats, and strong inhibition by acrylate, suggested that formation of 2-ethyl-3-carboxypropyl phthalate involved mitochondrial beta-oxidation. The strong enhancement of the production of this compound by clofibrate (a very weak inducer for mitochondrial dehydrogenases), and strong inhibition by chlorpromazine suggested that peroxisomes may also be able to oxidize 2-ethyl-5-carboxypentyl phthalate. We were able to detect beta-oxidation of 2-ethyl-5-carboxypentyl phthalate to 2-ethyl-3-carboxypropyl phthalate using purified mitochondria, but strong phthalate monoester hydrolase activity observed during incubation of the former compound with purified peroxisomes made it impossible to determine whether 2-ethyl-3-carboxypropyl phthalate could be produced in the latter organelle or not. 2-Ethyl-5-carboxypentyl phthalate was such an inefficient substrate for beta-oxidation compared to palmitic acid that it is unlikely that it contributes significantly to the production of H2O2 in rats chronically exposed to di-(2-ethylhexyl) phthalate. Normal fatty acids are most likely to serve as the dominant substrates for peroxisomal beta-oxidase.
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Pfäffli P. Phthalic acid excretion as an indicator of exposure to phthalic anhydride in the work atmosphere. Int Arch Occup Environ Health 1986; 58:209-16. [PMID: 3770961 DOI: 10.1007/bf00432103] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The concentration of phthalic acid was determined in the urine of nine subjects occupationally exposed to phthalic anhydride. For the determination, the urine samples were acidified, extracted with dimethyl ether, esterified with boron trifluoride/methanol and measured by electron capture gas chromatography. Environmental air samples were collected in Tenax tubes, eluted with methyl-t-butyl ether and assayed by electron capture gas chromatography. Significant correlations were found between the concentration in urine samples (range: 0.3-14.0 mumol/mmol creatinine), collected at different times of the day, and the time-weighed average atmospheric concentrations (range: 0.03-10.5 mg/m3). No conjugation of phthalic acid in the urine was observed. The detection limit for urine samples (10 ml) was 0.05 mumol/l) and that for air samples 0.4 microgram/m3. The method has potential for biological monitoring of workers exposed to phthalic anhydride. It was found that at atmospheric anhydride concentrations of about 30% of the hygienic reference value (6 mg/m3), which is applied in many market economies, a body-burden was caused which was not eliminated overnight.
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