Environmental exposure to pyrethroids and sperm sex chromosome disomy: a cross-sectional study

Abstract Background The role of environmental pesticide exposures, such as pyrethroids, and their relationship to sperm abnormalities are not well understood. This study investigated whether environmental exposure to pyrethroids was associated with altered frequency of sperm sex chromosome disomy in adult men. Methods A sample of 75 subjects recruited through a Massachusetts infertility clinic provided urine and semen samples. Individual exposures were measured as urinary concentrations of three pyrethroid metabolites ((3-phenoxybenzoic acid (3PBA), cis- and trans- 3-(2,2-Dichlorovinyl)-1-methylcyclopropane-1,2-dicarboxylic acid (CDCCA and TDCCA)). Multiprobe fluorescence in situ hybridization for chromosomes X, Y, and 18 was used to determine XX, YY, XY, 1818, and total sex chromosome disomy in sperm nuclei. Poisson regression analysis was used to examine the association between aneuploidy rates and pyrethroid metabolites while adjusting for covariates. Results Between 25-56% of the sample were above the limit of detection (LOD) for the pyrethroid metabolites. All sex chromosome disomies were increased by 7-30% when comparing men with CDCCA and TDCCA levels above the LOD to those below the LOD. For 3PBA, compared to those below the LOD, those above the LOD had YY18 disomy rates 1.28 times higher (95% CI: 1.15, 1.42) whereas a reduced rate was seen for XY18 and total disomy (IRR = 0.82; 95% CI: 0.77, 0.87; IRR = 0.93; 95% CI: 0.87-0.97), and no association was seen for XX18 and 1818. Conclusions Our findings suggest that urinary concentrations of CDCCA and TDCCA above the LOD were associated with increased rates of aneuploidy. However the findings for 3BPA were not consistent. This is the first study to examine these relationships, and replication of our findings is needed before the association between pyrethroid metabolites and aneuploidy can be fully defined.http://deepblue.lib.umich.edu/bitstream/2027.42/134538/1/12940_2013_Article_854.pd

Environmental exposure to pyrethroids and sperm sex chromosome disomy: A cross-sectional study

Background The role of environmental pesticide exposures, such as pyrethroids, and their relationship to sperm abnormalities are not well understood. This study investigated whether environmental exposure to pyrethroids was associated with altered frequency of sperm sex chromosome disomy in adult men. Methods A sample of 75 subjects recruited through a Massachusetts infertility clinic provided urine and semen samples. Individual exposures were measured as urinary concentrations of three pyrethroid metabolites ((3-phenoxybenzoic acid (3PBA), cis- and trans- 3-(2,2-Dichlorovinyl)-1-methylcyclopropane-1,2-dicarboxylic acid (CDCCA and TDCCA)). Multiprobe fluorescence in situ hybridization for chromosomes X, Y, and 18 was used to determine XX, YY, XY, 1818, and total sex chromosome disomy in sperm nuclei. Poisson regression analysis was used to examine the association between aneuploidy rates and pyrethroid metabolites while adjusting for covariates. Results Between 25-56% of the sample were above the limit of detection (LOD) for the pyrethroid metabolites. All sex chromosome disomies were increased by 7-30% when comparing men with CDCCA and TDCCA levels above the LOD to those below the LOD. For 3PBA, compared to those below the LOD, those above the LOD had YY18 disomy rates 1.28 times higher (95% CI: 1.15, 1.42) whereas a reduced rate was seen for XY18 and total disomy (IRR = 0.82; 95% CI: 0.77, 0.87; IRR = 0.93; 95% CI: 0.87-0.97), and no association was seen for XX18 and 1818. Conclusions Our findings suggest that urinary concentrations of CDCCA and TDCCA above the LOD were associated with increased rates of aneuploidy. However the findings for 3BPA were not consistent. This is the first study to examine these relationships, and replication of our findings is needed before the association between pyrethroid metabolites and aneuploidy can be fully defined

Sperm Aneuploidy in Faroese Men with Lifetime Exposure to Dichlorodiphenyldichloroethylene (DDE) and Polychlorinated Biphenyl (PCB) Pollutants.

Background: Although it is known that sperm aneuploidy contributes to early pregnancy losses and congenital abnormalities, the causes are unknown and environmental contaminants are suspected. Objectives: Our goal was to evaluate associations between lifetime exposure to organochlorines, specifically dichlorodiphenyldicholorethylene (p,p´-DDE) and polychlorinated biphenyls (PCBs), and sperm aneuploidy in men from the general population of the Faroe Islands, a population with a known history of organochlorine exposures. Methods: Serum and semen samples from men (n = 90) 22–44 years old who participated in Faroe Islands health studies were analyzed for p,p´-DDE and PCBs 118, 138, 153, and 180 and adjusted for total lipids. Cord blood and age-14 serum were available for a subgroup (n = 40) and were also analyzed for p,p´-DDE and PCBs. Sperm fluorescence in situhybridization (FISH) for chromosomes X, Y, and 18 was used to determine rates of XX18, XY18, YY18, and total disomy. Multivariable adjusted Poisson models were used to estimate the relationship between organochlorine exposure and sperm disomy outcomes. Results: Adult p,p´-DDE and total PCB serum concentrations were both associated with significantly increased rates of XX18, XY18, and total disomy. Age-14 p,p´-DDE and PCB concentrations were both associated with significantly increased rates of XX, XY, and total disomy in adulthood. Associations between cord blood concentrations of p,p´-DDE and PCBs and sperm disomy in adulthood were not consistently significant. Conclusions: Organochlorine exposures measured at age 14 and in adulthood were associated with sperm disomy in this sample of high-exposure men, suggesting that the impacts of persistent pollutants on testicular maturation and function require further investigation

Environmental and occupational pesticide exposure and numan sperm parameters: A systematic review

Of continuing concern are the associations between environmental or occupational exposures to pesticides and semen quality parameters. Prior research has indicated that there may be associations between exposure to pesticides of a variety of classes and decreased sperm health. The intent of this review was to summarize the most recent evidence related to pesticide exposures and commonly used semen quality parameters, including concentration, motility and morphology. The recent literature was searched for studies published between January, 2007 and August, 2012 that focused on environmental or occupational pesticide exposures. Included in the review are 17 studies, 15 of which reported significant associations between exposure to pesticides and semen quality indicators. Two studies also investigated the roles genetic polymorphisms may play in the strength or directions of these associations. Specific pesticides targeted for study included dichlorodiphenyltrichloroethane (DDT), hexachlorocyclohexane (HCH), and abamectin. Pyrethroids and organophosphates were analyzed as classes of pesticides rather than as individual compounds, primarily due to the limitations of exposure assessment techniques. Overall, a majority of the studies reported significant associations between pesticide exposure and sperm parameters. A decrease in sperm concentration was the most commonly reported finding among all of the pesticide classes investigated. Decreased motility was also associated with exposures to each of the pesticide classes, although these findings were less frequent across studies. An association between pesticide exposure and sperm morphology was less clear, with only two studies reporting an association. The evidence presented in this review continues to support the hypothesis that exposures to pesticides at environmentally or occupationally relevant levels may be associated with decreased sperm health. Future work in this area should focus on associations between specific pesticides or metabolic products and sperm quality parameters. Analysis of effects of varying genetic characteristics, especially in genes related to pesticide metabolism, also needs further attention

Disease and Health Inequalities Attributable to Air Pollutant Exposure in Detroit, Michigan

The environmental burden of disease is the mortality and morbidity attributable to exposures of air pollution and other stressors. The inequality metrics used in cumulative impact and environmental justice studies can be incorporated into environmental burden studies to better understand the health disparities of ambient air pollutant exposures. This study examines the diseases and health disparities attributable to air pollutants for the Detroit urban area. We apportion this burden to various groups of emission sources and pollutants, and show how the burden is distributed among demographic and socioeconomic subgroups. The analysis uses spatially-resolved estimates of exposures, baseline health rates, age-stratified populations, and demographic characteristics that serve as proxies for increased vulnerability, e.g., race/ethnicity and income. Based on current levels, exposures to fine particulate matter (PM2.5), ozone (O3), sulfur dioxide (SO2), and nitrogen dioxide (NO2) are responsible for more than 10,000 disability-adjusted life years (DALYs) per year, causing an annual monetized health impact of $6.5 billion. This burden is mainly driven by PM2.5 and O3 exposures, which cause 660 premature deaths each year among the 945,000 individuals in the study area. NO2 exposures, largely from traffic, are important for respiratory outcomes among older adults and children with asthma, e.g., 46% of air-pollution related asthma hospitalizations are due to NO2 exposures. Based on quantitative inequality metrics, the greatest inequality of health burdens results from industrial and traffic emissions. These metrics also show disproportionate burdens among Hispanic/Latino populations due to industrial emissions, and among low income populations due to traffic emissions. Attributable health burdens are a function of exposures, susceptibility and vulnerability (e.g., baseline incidence rates), and population density. Because of these dependencies, inequality metrics should be calculated using the attributable health burden when feasible to avoid potentially underestimating inequality. Quantitative health impact and inequality analyses can inform health and environmental justice evaluations, providing important information to decision makers for prioritizing strategies to address exposures at the local level

Human sperm sex chromosome disomy and sperm DNA damage assessed by the neutral comet assay.

STUDY QUESTION: Is there an association between human sperm sex chromosome disomy and sperm DNA damage? SUMMARY ANSWER: An increase in human sperm XY disomy was associated with higher comet extent; however, there was no other consistent association of sex chromosome disomies with DNA damage. WHAT IS KNOWN ALREADY: There is limited published research on the association between sex chromosome disomy and sperm DNA damage and the findings are not consistent across studies. STUDY DESIGN, SIZE, AND DURATION: We conducted a cross-sectional study of 190 men (25% ever smoker, 75% never smoker) from subfertile couples presenting at the Massachusetts General Hospital Fertility Clinic from January 2000 to May 2003. PARTICIPANTS/MATERIALS, SETTING, METHODS: Multiprobe fluorescence in situ hybridization for chromosomes X, Y and 18 was used to determine XX, YY, XY and total sex chromosome disomy in sperm nuclei using an automated scoring method. The neutral comet assay was used to measure sperm DNA damage, as reflected by comet extent, percentage DNA in the comet tail, and tail distributed moment. Univariate and multiple linear regression models were constructed with sex chromosome disomy (separate models for each of the four disomic conditions) as the independent variable, and DNA damage parameters (separate models for each measure of DNA damage) as the dependent variable. MAIN RESULTS AND THE ROLE OF CHANCE: Men with current or past smoking history had significantly greater comet extent (µm: regression coefficients with 95% CI) [XX18: 15.17 (1.98, 28.36); YY18: 14.68 (1.50, 27.86); XY18: 15.41 (2.37, 28.45); Total Sex Chromosome Disomy: 15.23 (2.09, 28.38)], and tail distributed moment [XX18: 3.01 (0.30, 5.72); YY18: 2.95 (0.24, 5.67); XY18: 3.04 (0.36, 5.72); Total Sex Chromosome Disomy: 3.10 (0.31, 5.71)] than men who had never smoked. In regression models adjusted for age and smoking, there was a positive association between XY disomy and comet extent. For an increase in XY disomy from 0.56 to 1.47% (representing the 25th to 75th percentile), there was a mean increase of 5.08 µm in comet extent. No other statistically significant findings were observed. LIMITATIONS, REASONS FOR CAUTION: A potential limitation of this study is that it is cross-sectional. Cross-sectional analyses by nature do not lend themselves to inference about directionality for any observed associations; therefore we cannot determine which variable is the cause and which one is the effect. A small sample size may be a further limitation. Comparison of these findings to other studies is limited due to methodological differences. WIDER IMPLICATIONS OF THE FINDINGS: Although consistent associations across sex chromosome disomies or DNA damage measures were not observed, this study highlights the need to explore etiologies of sperm DNA damage and sex chromosome disomy to better understand the potential mechanistic overlaps between the two. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by NIOSH Grant T42 OH008416, and NIH/NIEHS Grants ES 009718, ES 000002, and R01 ES017457. During the study M.E.M. was affiliated with the Department of Environmental Health at the Harvard School of Public Health. TRIAL REGISTRATION NUMBER: N/A

Semi-Automated Scoring of Triple-Probe FISH in Human Sperm Using Confocal Microscopy

Aneuploidy, or an abnormal number of chromosomes, is found in human gametes and is caused by errors during meiosis. Although most human fetuses conceived from aneuploid gametes do not survive to term, some aneuploid conceptuses do result in offspring with compromised phenotypes. Kleinfelters, Turners, and XYY syndromes are examples of well-characterized chromosomal disorders resulting from aneuploid conceptuses. To study sperm aneuploidy and its impacts on fertility and reproduction, fluorescence in situ hybridization (FISH) is used to quantify the frequency of aneuploidy in sperm and requires the scoring of thousands of nuclei. Traditional manual scoring of FISH sperm can be time consuming, which can lead to scorer fatigue and increased error. Semi-automated methods that rely on computer software to objectively count fluorescence signals using specified criteria are needed. In this validation study, we used a Zeiss LSM 710 confocal microscope combined with the Zen software (Zeiss, Jena, Germany) for image acquisition. Application of online spectral linear unmixing allowed for effective separation of the four fluorochromes used to identify chromosomes X, Y, 18 and the nuclei. Image processing, segmentation, classification, and scoring were performed using custom analysis software developed in MATLAB®. The semi-automated results were compared with manual scoring results in 10 slides. In comparing percent disomy calculated by each scoring method for each slide, a significant difference was found on one slide for XX18 (0.62% automated vs 0.05% manual). For the other 9 slides, XX18 estimates were comparable by method, as were the YY18 and XY18 estimates across all 10 slides. These results demonstrate that semi-automated methods using spectral imaging on a confocal microscope are a feasible approach for analyzing numerical chromosomal aberrations in sperm, and are comparable to manual methods

Dialkyl phosphate urinary metabolites and chromosomal abnormalities in human sperm.

BACKGROUND: The past decade has seen numerous human health studies seeking to characterize the impacts of environmental exposures, such as organophosphate (OP) insecticides, on male reproduction. Despite an extensive literature on OP toxicology, many hormone-mediated effects on the testes are not well understood. OBJECTIVES: This study investigated environmental exposures to OPs and their association with the frequency of sperm chromosomal abnormalities (i.e., disomy) among adult men. METHODS: Men (n=159) from a study assessing the impact of environmental exposures on male reproductive health were included in this investigation. Multi-probe fluorescence in situ hybridization (FISH) for chromosomes X, Y, and 18 was used to determine XX18, YY18, XY18 and total disomy in sperm nuclei. Urine was analyzed using gas chromatography coupled with mass spectrometry for concentrations of dialkyl phosphate (DAP) metabolites of OPs [dimethylphosphate (DMP); dimethylthiophosphate (DMTP); dimethyldithiophosphate (DMDTP); diethylphosphate (DEP); diethylthiophosphate (DETP); and diethyldithiophosphate (DEDTP)]. Poisson regression was used to model the association between OP exposures and disomy measures. Incidence rate ratios (IRRs) were calculated for each disomy type by exposure quartiles for most metabolites, controlling for age, race, BMI, smoking, specific gravity, total sperm concentration, motility, and morphology. RESULTS: A significant positive trend was seen for increasing IRRs by exposure quartiles of DMTP, DMDTP, DEP and DETP in XX18, YY18, XY18 and total disomy. A significant inverse association was observed between DMP and total disomy. Findings for total sum of DAP metabolites concealed individual associations as those results differed from the patterns observed for each individual metabolite. Dose-response relationships appeared nonmonotonic, with most of the increase in disomy rates occurring between the second and third exposure quartiles and without additional increases between the third and fourth exposure quartiles. CONCLUSIONS: This is the first epidemiologic study of this size to examine the relationship between environmental OP exposures and human sperm disomy outcomes. Our findings suggest that increased disomy rates were associated with specific DAP metabolites, suggesting that the impacts of OPs on testis function need further characterization in epidemiologic studies