A comprehensive analysis of plausible genotoxic covariates among workers of a polyvinyl chloride plant exposed to vinyl chloride monomer

Protective role of selenium on structural change of human hemoglobin in the presence of vinyl chloride

Vinyl chloride is a colorless gas with a pleasant odor capable of entering the body through oral or inhalation routes. Extensive studies on this compound indicated that it is a carcinogen, and Vinyl chloride exposure can result in a specific type of cancer in vinyl chloride workers. Whereas hemoglobin plays a vital role in oxygen transfer throughout the body, in a molecular aspect, the effect of vinyl chloride on human hemoglobin has not been studied. Furthermore, selenium as an antioxidant is a vital factor for the health of humans and animals. Then this research investigated the effect of the antioxidant capability of selenium at the same concentrations in blood on the interaction between vinyl chloride and hemoglobin. UV-visible, Fourier-transform infrared, chemiluminescence, and fluorescence spectroscopies were employed. The results indicated the destruction of hemoglobin structure in different concentrations of vinyl chloride. At the same time, the antioxidant effect of selenium inhibited the destructive impact of vinyl chloride on hemoglobin structure.

Environmental exposures associated with elevated risk for autism spectrum disorder may augment the burden of deleterious de novo mutations among probands

Although the full aetiology of autism spectrum disorder (ASD) is unknown, familial and twin studies demonstrate high heritability of 60-90%, indicating a predominant role of genetics in the development of the disorder. The genetic architecture of ASD consists of a complex array of rare and common variants of all classes of genetic variation usually acting additively to augment individual risk. The relative contribution of heredity in ASD persists despite selective pressures against the classic autistic phenotype; a phenomenon thought to be explained, in part, by the incidence of spontaneous (or de novo) mutations. Notably, environmental exposures attributed as salient risk factors for ASD may play a causal role in the emergence of deleterious de novo variations, with several ASD-associated agents having significant mutagenic potential. To explore this hypothesis, this review article assesses published epidemiological data with evidence derived from assays of mutagenicity, both in vivo and in vitro, to determine the likely role such agents may play in augmenting the genetic liability in ASD. Broadly, these exposures were observed to elicit genomic alterations through one or a combination of: (1) direct interaction with genetic material; (2) impaired DNA repair; or (3) oxidative DNA damage. However, the direct contribution of these factors to the ASD phenotype cannot be determined without further analysis. The development of comprehensive prospective birth cohorts in combination with genome sequencing is essential to forming a causal, mechanistic account of de novo mutations in ASD that links exposure, genotypic alterations, and phenotypic consequences.

Mutations in apoptotic genes and micronucleus occurrence in vinyl chloride-exposed workers in China

BACKGROUND

Vinyl chloride is an occupational carcinogen which caused micronuclei in human directly. It has recently been demonstrated that micronuclei formation could generate a spectrum of genomic rearrangements and play a key role in the early tumorigenesis process. We aimed to investigate the association between polymorphisms in the apoptosis process related genes and micronuclei rate in vinyl chloride-exposed workers in China.

MATERIALS AND METHODS

Cytokinesis block micronucleus test was performed on 342 vinyl chloride-exposed workers and 107 nonexposed workers to determine chromosomal damage. The polymerase chain reaction and restriction fragment length polymorphism technique were used to detect nine Single Nucleotide Polymorphisms in the apoptosis process related genes.

RESULTS

There was a highly significant dose-response relationship between vinyl chloride exposure and chromosomal damage. Individuals carrying the variant heterozygote MDM2 -309T > G (rs2279744) and variant homozygote BCL2 -938C > A (rs2279115) were at higher risk for chromosomal damage compared with their wild-type genotype, respectively. Although individuals possessing the variant genotype of BAX -248G > A (rs4645878) had decreased risk compared with the corresponding wild type, this did not reach statistical significant.

CONCLUSION

Genetic polymorphisms in genes related to apoptosis process may have an impact on chromosomal damage induced by vinyl chloride. Environ. Mol. Mutagen. 58:39-45, 2017. © 2016 Wiley Periodicals, Inc.

Exploring a new method for the biological monitoring of plastic workers exposed to the vinyl chloride monomer

Vinyl chloride monomer (VCM) is widely used in the production of polyvinyl chloride (PVC) plastics. VCM is recognized as a confirmed human and animal carcinogenic compound. Recent studies have reported poor health of plastic workers, even having exposure at concentrations below the permissible limit to VCM. There has not been any study regarding exposed workers to VCM in Iran. Similarly, no information exists as to the biological monitoring of such workers. The main purpose of this study was to conduct a thorough occupational and biological monitoring of Iranian plastic workers exposed to VCM.A total of 100 workers from two plastic manufacturing plants (A and B) in Tehran along with 25 unexposed workers as controls were studied. The personal monitoring of all nonsmoking workers exposed to VCM at two plastic manufacturing plants (A and B) was performed in the morning shift (8 a.m. to 4 p.m.) according to the National Institute For Occupational Safety And Health method no. 1007.Biological monitoring of workers was carried out through collection of exhaled breath of all exposed and control workers in Tedlar bags and with a subsequent analysis using gas chromatography-flame ionization detector.Not only the mean occupational exposure of workers to VCM at plant A was higher than the respective threshold limit value but also the statistical significance was higher than workers at plant B. Similarly, VCM concentration in exhaled breath of workers at plant A was also statistically significantly higher than at plant B. Correlation of occupational exposure of all workers to vinyl chloride with its concentration in exhaled breath was statistically significant.This is the first study on biological monitoring for exposed plastic workers to VCM using exhaled breath. On the basis of the results in this study, a novel method of biological monitoring of plastic workers was proposed.

The long-term effects of occupational exposure to vinyl chloride monomer on microcirculation: a cross-sectional study 15 years after retirement

OBJECTIVES

To assess residual long-term microcirculation abnormalities by capillaroscopy, 15 years after retiring from occupational exposure to vinyl chloride monomer (VCM).

DESIGN

Cross-sectional study.

SETTING

Allier, one of the major areas of polyvinyl chloride production in France.

PARTICIPANTS

We screened 761 (97% men) retired workers exposed to chemical toxics. Exposure to chemicals other than VCM excluded potential participants.

PRIMARY AND SECONDARY OUTCOME MEASURES

These participants underwent a medical examination including a capillaroscopy, symptoms of Raynaud and comorbidities, as well as a survey to determine exposure time, direct or indirect contact, type of occupation, smoking status and time after exposure. A double blind analysis of capillaroscopic images was carried out. A control group was matched in age, sex, type of occupation.

RESULTS

179/761 retired workers were only exposed to VCM at their work, with 21 meeting the inclusion criteria and included. Exposure time was 29.8±1.9 years and time after exposure was 15.9±2.4 years. Retired workers previously exposed to VCM had significantly higher capillaroscopic modifications than the 35 controls: enlarged capillaries (19% vs 0%, p<0.001), dystrophy (28.6% vs 0%, p=0.0012) and augmented length (33% vs 0%, p<0.001). Time exposure was linked (p<0.001) with enlarged capillaries (R(2)=0.63), dystrophy (R(2)=0.51) and capillary length (R(2)=0.36). They also had higher symptoms of Raynaud (19% vs 0%, p=0.007) without correlation with capillaroscopic modifications.

CONCLUSIONS

Although VCM exposure was already known to affect microcirculation, our study demonstrates residual long-term abnormalities following an average of 15 years' retirement, with a time-related exposure response. Symptoms of Raynaud, although statistically associated with exposure, were not related to capillaroscopic modifications; its origin remains to be determined.