title: Cytogenetic biomarkers, urinary metabolites and metabolic gene polymorphisms in workers exposed to styrene.
abstract: The present study comprised a biomonitoring study in 95 workers occupationally exposed to styrene and 98 unexposed controls, employing an integrated approach involving biomarkers of exposure, effect, and susceptibility. Airborne styrene was evaluated at workplace, and urinary styrene metabolites, mandelic acid (MA), phenylglyoxylic acid (PGA), vinylphenols (VPTs) and phenylhydroxyethylmercapturic acids (PHEMAs), were measured as biomarkers of internal dose. Cytogenetic alterations were evaluated by analysing the frequency of chromosomal aberrations (CAs) and micronucleated binucleated cells (MNBN) in peripheral blood lymphocytes. The micronucleus assay was coupled with centromeric fluorescence in situ hybridization to distinguish micronuclei (MN) arising from chromosomal breakage (C- MN) from those harboring whole chromosomes (C+ MN). The possible influence of genetic polymorphisms of xenobiotic-metabolizing enzymes involved in styrene biotransformation (EPHX1, GSTT1, GSTM1, GSTP1) and NAT2 on the cytogenetic endpoints was investigated. The exposed workers showed a significantly higher frequency of MNBN (13.8+/-0.5% versus 9.2+/-0.4%; P<0.001) compared to control subjects. The effect appeared to concern both C- and C+ MN. A positive correlation was seen between the frequency of C+ MN and urinary level of MA+PGA (P<0.05) and VPTs (P<0.001). Chromosome-type CAs positively correlated with airborne styrene level and VPTs (P<0.05), whereas chromatid-type CAs correlated with PHEMAs (P<0.05). Workers bearing GSTM1 null genotype showed lowered levels of PHEMAs (P<0.001). The GSTT1 null genotype was associated with increased MNBN frequencies in the exposed workers (P<0.05) and the fast activity EPHX genotype with a moderate decrease in both MNBN and CAs in the controls. Our results suggest that occupational exposure to styrene has genotoxic effects that are potentiated by the GSTT1 gene deletion. These observations may have relevance considering the risk of lymphatic and haematopoietic malignancies tentatively associated with styrene exposure.
authors.affiliation: Department of Human and Environmental Sciences, University of Pisa, Italy. l.migliore@geog.unipi.it
authors.forename: Lucia
authors.initials: L
authors.lastname: Migliore
authors.forename: Alessio
authors.initials: A
authors.lastname: Naccarati
authors.forename: Fabio
authors.initials: F
authors.lastname: Coppedè
authors.forename: Enrico
authors.initials: E
authors.lastname: Bergamaschi
authors.forename: Giuseppe
authors.initials: G
authors.lastname: De Palma
authors.forename: Anu
authors.initials: A
authors.lastname: Voho
authors.forename: Paola
authors.initials: P
authors.lastname: Manini
authors.forename: Hilkka
authors.initials: H
authors.lastname: Järventaus
authors.forename: Antonio
authors.initials: A
authors.lastname: Mutti
authors.forename: Hannu
authors.initials: H
authors.lastname: Norppa
authors.forename: Ari
authors.initials: A
authors.lastname: Hirvonen
mesh_terms: D002869:Chromosome Aberrations; D003582:Cytogenetics / Q000379:methods*; D005260:Female; D005819:Genetic Markers / Q000235:genetics*; D005838:Genotype; D006038:Glyoxylates / Q000378:metabolism; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008333:Mandelic Acids / Q000378:metabolism; D015162:Micronucleus Tests; D016273:Occupational Exposure; D010597:Pharmacogenetics / Q000379:methods*; D010636:Phenols / Q000378:metabolism; D011102:Polyhydroxyethyl Methacrylate / Q000378:metabolism; D011110:Polymorphism, Genetic; D013343:Styrenes / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D005819:Genetic Markers; D006038:Glyoxylates; D008333:Mandelic Acids; D010636:Phenols; D013343:Styrenes; D011102:Polyhydroxyethyl Methacrylate; C012482:phenylglyoxylic acid; C037938:mandelic acid