THE QUEST FOR BIOMARKERS OF EXPOSURE

Transcription

1 THE QUEST FR BIMARKERS F EXPSURE T NN-PERSISTENT CHEMICALS Holger M. Koch koch@ipa-dguv.de Institute for Prevention and ccupational Medicine of the German Social Accident Insurance Institute of the Ruhr-University Bochum (IPA) Bürkle-de-la-Camp-Platz Bochum, Germany

2 Exposure Assessment (in the exposure-disease continuum) Ambient Monitoring Medical Assessment external exposure chemicals: model calculations, including - various sources of exposure (known and unknown) - routes of exposure (oral, inhalative, dermal) health effects in air, soil, water, diet, consumer products Exposure and Risk Estimation adapted from: Biological Monitoring- Prospects in ccupational and Environmental Medicine Angerer and Weiss (eds.), Wiley-VCH, Weinheim, 1. Edition (2002) 2

3 Exposure Assessment (in the exposure-disease continuum) Ambient Monitoring Human Biomonitoring Medical Assessment external exposure Biomarkers of Exposure Biochemical Effect Markers Biological Effect Markers health effects chemicals: in air, soil, water, diet, consumer products parent chem., metabolites protein adducts DNA adducts cytogenetic parameters, enzymes Exposure and Risk Estimation adapted from: Biological Monitoring- Prospects in ccupational and Environmental Medicine Angerer and Weiss (eds.), Wiley-VCH, Weinheim, 1. Edition (2002) 3

4 Exposure Assessment (in the exposure-disease continuum) Ambient Monitoring Human Biomonitoring Medical Assessment external exposure Biomarkers of Exposure Biochemical Effect Markers Biological Effect Markers health effects chemicals: in air, soil, water, diet, consumer products parent chem., metabolites protein adducts DNA adducts cytogenetic parameters, enzymes Specificity to health effects Specificity to chemical exposure Exposure and Risk Estimation adapted from: Biological Monitoring- Prospects in ccupational and Environmental Medicine Angerer and Weiss (eds.), Wiley-VCH, Weinheim, 1. Edition (2002) 4

5 Biomarkers of Exposure defined by: Biomarkers of Exposure - specific to target compound (exposure) ability to capture all: - sources of exposure (known and unknown) - routes of exposure (oral, inhalative, dermal) parent Toxikokinetics chem., metabolites Metabolism Matrix (urine, blood, etc.) Specificity Contamination 5

6 Toxikokinetics: persistent chemicals Blood Toxicant/Metabolite Long elimination half-times Higher blood levels relative to urine Blood is preferred matix Urinary Metabolite Time (Days) taken from ISEA/ISES Wesolowski Award Presentation, Paris 2006: Biomonitoring: An Integral Part of Exposure Analysis Larry L. Needham, Ph.D., National Center for Environmental Health, Centers for Disease Control and Prevention Needham and Sexton. JEAEE 10: (2000) Henderson et al. Crit Rev Toxicol 20: (1989) 6

7 Toxikokinetics: non-persistent chemicals Blood Toxicant/Metabolite Urinary Metabolite Urinary Metabolite 2 Quick metabolisation Short elimination half-times Higher urine levels relative to blood Urine is preferred matrix Urinary Metabolite Time (Days) taken from ISEA/ISES Wesolowski Award Presentation, Paris 2006: Biomonitoring: An Integral Part of Exposure Analysis Larry L. Needham, Ph.D., National Center for Environmental Health, Centers for Disease Control and Prevention Needham and Sexton. JEAEE 10: (2000) Henderson et al. Crit Rev Toxicol 20: (1989) 7

8 Concentration (in µg/l) Biomarkers: non-persistent chemicals Toxikokinetics: n-butyl phthalate 5mg D4-DnBuP (oral, one human volunteer) MnBP 3H-MnBP serum time (in h) Koch et al (2012) Arch Tox 86, Lorber and Koch (2013) Environ Int 59,

9 Concentration (in µg/l) Biomarkers: non-persistent chemicals Toxikokinetics: n-butyl phthalate 5mg D4-DnBuP (oral, one human volunteer) MnBP 3H-MnBP MnBP 3H-MnBP urine serum time (in h) Koch et al (2012) Arch Tox 86, Lorber and Koch (2013) Environ Int 59,

10 Concentration (in µg/l) Biomarkers: non-persistent chemicals Toxikokinetics: n-butyl phthalate 5mg D4-DnBuP (oral, one human volunteer) MnBP 3H-MnBP MnBP 3H-MnBP urine serum time (in h) Koch et al (2012) Arch Tox 86, Lorber and Koch (2013) Environ Int 59,

11 Concentration (in µg/l) Biomarkers: non-persistent chemicals Toxikokinetics: iso-butyl paraben 5mg D4-iso-butyl paraben (oral, one human volunteer) iso-bup 2H-iso-BuP serum time (in h) Moos et al. (e-pub 11/25/2015) Arch Tox Serum data in preparation 11

12 Concentration (in µg/l) Biomarkers: non-persistent chemicals Toxikokinetics: iso-butyl paraben 5mg D4-iso-butyl paraben (oral, one human volunteer) urine serum time (in h) iso-bup 2H-iso-BuP iso-bup 2H-iso-BuP Urine is preferred matrix Moos et al (e-pub 11/25/2015) Arch Tox Serum data in preparation 12

13 Biomarkers: non-persistent chemicals Metabolism Parent chemical Parent chemical Parent chemical -gluc -sulf Metabolite A Metabolite A -gluc -sulf Metabolite B Metabolite C Metabolite B Metabolite C -gluc -sulf -gluc -sulf Phase I Phase II 13

14 Biomarkers: non-persistent chemicals Metabolism Parent chemical Parent chemical Parent chemical -gluc -sulf Metabolite A Metabolite A -gluc -sulf Metabolite B Metabolite C Metabolite B Metabolite C -gluc -sulf -gluc -sulf Enzymatic deconjugation Phase I Phase II 14

15 Biomarkers: non-persistent chemicals Metabolism Parent chemical Parent chemical Metabolite A Metabolite B Metabolite C Be careful! know, which conjugates you want to cleave (e.g. phthalates: gluc; parabens: gluc+sulfates ) check stability of target analytes (e.g. phthalates are broken down by aryl-sulfatases) Partial deconjugation or analyte breakdown! Enzymatic deconjugation Phase I Phase II 15

16 Biomarkers: non-persistent chemicals Conjugate Distribution (Parabens) Methyl Paraben n-butyl Paraben 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% free [%] sul [%] glu [%] 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% free [%] sul [%] glu [%] to transform all conjugates into free phase I metabolites Gluc-sulf-enzyme (like HP2) is needed Gluc-sulf-enzymes cleave ester-bonds of phthalates; Phthalates/substitutes need pure Gluc-enzyme (like E.coli K12) Moos et al (e-pub 11/25/2015) Arch Tox 16

17 Biomarkers: non-persistent chemicals Metabolism Parent chemical Parent chemical Metabolite A Metabolite B Metabolite C 17

18 Biomarkers: non-persistent chemicals Metabolism Parent chemical Parent chemical 3% Possible Contamination! Metabolite A 75% Back-calculation of the dose with metabolite conversion factors (F ue ) Metabolite B Metabolite C 5% 15% chemical X chemical Y Biomarker Specificity! 18

19 Biomarkers: non-persistent chemicals Metabolism (example parabens) H Methyl Paraben R H H PHBA H Methyl Paraben R 3% 17% (free, glucuronideand sulphateconjugates) H NH PHHA H 60% Moos et al (e-pub 11/25/2015) Arch Tox 19

20 Biomarkers: non-persistent chemicals Metabolism (example parabens) ther chemicals H MeP R H iso-bup H 3 C CH 3 H n-bup CH3 H H H H PHBA H 3-7% MeP 17% R iso-bup 6.8% H 3 C CH 3 n-bup 5.6% CH3 H NH PHHA H 57-64% Parent parabens as biomarkers: Different excretion fractions Rather low excretion fractions Contamination control! Preservative in biobanked samples* Moos et al (e-pub 11/25/2015) Arch Tox * Longnecker et al. (2013) Environ Res 126, (2013). 20

21 Biomarkers: non-persistent chemicals Metabolism (example parabens) H H H dose extrapolation (daily intakes) MeP R iso-bup H 3 C CH 3 n-bup CH3 risk assessment (comparison to health benchmarks, HQ/HI) H MeP 17% R H iso-bup 6.8% H 3 C CH 3 H n-bup 5.6% CH3 H H Poster! 2H iso-bup 15.8% H CH 3 3H n-bup 5.8% H CH3 Moos et al (publication submitted) Moos et al (e-pub 11/25/2015) Arch Tox 21

22 Biomarkers: non-persistent chemicals Metabolism (example phthalates) C C C H ( ) 3 C H ( ) 3 Di(2-ethylhexyl)phthalate (DEHP) Chain length Phthalate H C H ( ) 3 2-Ethylhexanol Monoester- Metabolite C C C H ( ) 3 H Mono(2-ethylhexyl)phthalate (MEHP) f ue-pm H C H ( ) 3 2-Ethylhexanol C C H H Phthalic Acid Pre-Analytical / Analytical reference Koch estimated et al. (2005), Anderson et al. (2011), Kessler et al. (2012) 82 DEHP DEP MEHP MEP ~80% 6% 4 DnBP MnBP 84% Koch et al. (2012), Anderson et al. (2001) Personal 4 DiBP MiBP 71% Koch et al. (2012) Anderson et al. (2001) Care Products 6 BBzP MBzP 73% Anderson et al. (2001) Koch et al. (2005), Anderson et al. (2011), Kessler et al. (2012) 8 DEHP MEHP 6% Plasticizers Koch et al. (2007), Anderson et al. (2011) 9 DiNP MiNP 1% 10 DIDP/DPHP MiDP/MPHP <1% Contamination! Wittassek et al. (2008), Schütze et al. (2014) Koch et al. (2004) Arch Toxicol 78, Koch et al. (2005) Arch Toxicol 79,

23 Biomarkers: non-persistent chemicals Metabolism (example DEHP) C C C H ( ) 3 C H ( ) 3 Di(2-ethylhexyl)phthalate (DEHP) H C H ( ) 3 2-Ethylhexanol C C C H ( ) 3 H Mono(2-ethylhexyl)phthalate (MEHP) H C H ( ) 3 2-Ethylhexanol C C H H Phthalic Acid H R C H ( ) 3 2-(2-Hydroxyethyl)- hexylphthalate C H H R C H ( ) 3 2-(1-Hydroxyethyl)- hexylphthalate R C H ( ) 3 H 2-Ethyl-6-hydroxyhexylphthalate (<5%) R C H ( ) 2 C H H 23.3% 2-Ethyl-5-hydroxy- Hexylphthalate (5H-MEHP) R C H C H H t 1/2 10h 2-Ethyl-4-hydroxyhexylphthalate C H R C H ( ) 3 C R C H ( ) 3 R C H ( ) 3 C H 2-Carboxymethyl- ~4.2% 2-(1-xyethyl)- 2-Ethyl-5-carboxy hexylphthalate t 18.5% 1/2 hexylphthalate pentylphthalate (2cx-MMHP) (5cx-MEPP) >24h t 1/2 15h R C H ( ) 2 C 15.0% 2-Ethyl-5-oxy- Hexylphthalate (5oxo-MEHP) t 1/2 10h R C H C 2-Ethyl-4-oxyhexylphthalate Koch et al. (2004) Arch Toxicol 78, Koch et al. (2005) Arch Toxicol 79,

24 Biomarkers: non-persistent chemicals Biomarkers of exposure for phthalates Chain length Phthalate Monoester Metabolite f ue-pm Secondary metabolite f ue-pm reference 2 DEP MEP 80% estimated 4 DnBP MnBP 84% Koch et al. (2012), Anderson et al. (2001) H-MnBP 7% 4 DiBP MiBP 71% Koch et al. (2012) Anderson et al. (2001) H-MiBP 20% 6 BBzP MBzP 73% Anderson et al. (2001) 8 DEHP MEHP 6% Koch et al. (2005), Anderson et al. (2011), Kessler et al. (2012) 5H-MEHP 23% 5oxo-MEHP 15% 5cx-MEPP 18% 9 DiNP MiNP 1% Koch et al. (2007), Anderson et al. (2011) 10 DPHP /DiDP H-MiNP 18% oxo-minp 10% cx-minp 9% H-MPHP 12% Schütze et al. (2014), Wittassek and Angerer (2008) oxo-mphp 14% cx-mphp 0.5% 24

25 Biomarkers: non-persistent chemicals Metabolism (phthalate substitutes) Hexamoll DINCH : market introduction in 2002 DINCH C 9 H 19 MINCH H <1% C 9 H 19 H H-MINCH 11% H cx-minch 2% H H H oxo-minch 2% CHDA H H 24% Schütze et al. (2012) J Chrom B , Koch et al. (2013) Arch Tox 87, Schütze et al. (2015) Chemosphere 128, Schütze et al. (e-pub) Arch Tox 25

26 DINCH market introduction Biomarkers: non-persistent chemicals Hexamoll DINCH : Population Study German Environmental Specimen Bank: 24 h urine samples with full info on 24 h urine volume, body weight, etc. Year 26

27 H- + cx-minch in Urine (µg/l) DINCH market introduction Biomarkers: non-persistent chemicals Hexamoll DINCH : Population Study HBM I (H-MINCH + cx-minch): adults 4500µg/L children 3000 μg/l ? Exposure Assessment: metabolite levels in urine daily intake calculation Risk Assessment: Comparison with TDI HBM values (UBA) 0.01 Year Schütze et al. (2014) Int J Hyg Environ Health 217, HBM Commission (2012) Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz 57 (12),

28 Biomarkers: non-persistent chemicals Metabolism (phthalate substitutes) DEHTP (Terephthalate) DEHTP H DEHP MEHTP H 5H-MEHTP 2cx-MMHTP 5cx-MEPTP 1.8% 0.3% 13% H H H H H H 5oxo-MEHTP 1.0% Poster! Lessmann et al. (2016) J Chrom B. 1011, Lessmann et al. (accepted) Arch Tox. 28

29 Biomarkers: non-persistent chemicals Summary and conclusion Biomarkers of exposure to non-persistent chemicals Urine is preferred matrix Toxikokinetics Metabolism Parent chemical phase I met. phase II met (conjugates) Metabolite conversion factors Specificity Contamination Exposure Assessment (comparisons; dose) Risk Assessment (TDI; HBM/BE) Risk Management 29

30 Biomarkers: non-persistent chemicals Acknowledgement Some of the work has been performed within the Cooperation for the enhancement of HBM between the German Ministry for the Environment, the German Environment Agency (UBA), and the German Chemical Industry Association (VCI) IPA: 30

31 THE QUEST FR BIMARKERS F EXPSURE T NN-PERSISTENT CHEMICALS Holger M. Koch koch@ipa-dguv.de Institute for Prevention and ccupational Medicine of the German Social Accident Insurance Institute of the Ruhr-University Bochum (IPA) Bürkle-de-la-Camp-Platz Bochum, Germany

32 low-molecular weight phthalates high-molecular weight phthalates parent phthalate primary metabolite (hydrolytic monoester) secondary metabolite (oxidised monoester) parent phthalate primary metabolite (hydrolytic monoester) secondary metabolite (oxidised monoester) Dimethyl phthalate (DMP) Diethyl phthalate (DEP) Di-cyclohexyl phthalate (DCHP) Di-n-penty lphthalate (DnPeP) Butyl-benzyl phthalate (BBzP) Di-iso-butyl phthalate (DiBP) Di-n-butyl phthalate (DnBP) Mono-methyl phthalate (MMP) H Mono-ethyl phthalate (MEP) H Mono-cyclohexyl phthalate (MCHP) H Mono-n-pentyl phthalate (MnPeP) H Mono-benzyl phthalate (MBzP) H Mono-iso-butyl phthalate (MiBP) H Mono-n-butyl phthalate (MnBP) H n.a. n.a. n.a. Di(2-ethylhexyl) phthalate (DEHP) n.a. Di-iso-nonyl phthalate (DiNP) *1 n.a. 3H-Mono-methylpropyl phthalate (H-MiBP) H H 3H-Mono-n-butyl phthalate (H- MnBP) H H Di-iso-decyl phthalate (DiDP) *1 and Dipropylheptyl phthalate (DPHP) Mono(2-ethylhexyl) phthalate (MEHP) H Mono-iso-nonyl phthalate (MiNP) *1 H Mono-iso-decyl phthalate *1 (MiDP or MPHP) H 5H-Mono(2-ethylhexyl) phthalate (5H-MEHP or MEHHP) H H 5oxo-Mono(2-ethylhexyl) phthalate (5oxo-MEHP or MEHP) H 5carboxy- Mono(2-ethylhexyl) phthalate (5cx-MEPP or MECPP) H H 7H-Mono-methyloctyl phthalate (H-MiNP or MHiNP) H H 7oxo-Mono-methyloctyl phthalate (oxo-minp or MiNP) H 7carboxy-Mono-methylheptyl phthalate (cx-minp or MCiP) H H 6H-Mono-propylheptyl phthalate (H-MPHP, H-MiDP or MHiDP) H H Koch and Calafat (2009): H Phil Trans R Soc B 364: carboxy-Mono-propyl phthalate (3cx-MiBP or MCPP) H 6oxo-Mono-propylheptylphthalate (oxo-mphp, oxo-midp or MiDP) H