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

Does pyrethroid exposure lower human semen quality? a systematic review and meta-analysis

Background: Pyrethroids are natural organic compounds extracted from flowers of pyrethrums and commonly used as domestic and commercial insecticides. Although it is effective in insect and parasitic control, its associated toxicity, including spermotoxicity, remains a challenge globally. Currently, the available reports on the effect of pyrethroids on semen quality are conflicting, hence an evaluation of its detrimental effect is pertinent. This study conducts a detailed systematic review and meta-analysis of the effects of pyrethroids on sperm quality. Materials and methods: The present study was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Using a pre-defined strategic protocol, an internet search was done using combined text words. The criteria for eligibility were selected based on Population, Exposure, Comparator, Outcome, and Study Designs (PECO) framework, and relevant data were collected. Appraisal was done using The Office of Health Assessment and Translation (OHAT) tool for the evaluation of the Risk of Bias and the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) Working Group guidelines for the certainty of evidence. A quantitative meta-analysis was conducted with the Review Manager (RevMan). Results: Only 12 out of the 4, 050 studies screened were eligible for inclusion in this study. The eligible studies were from China (4), Japan (3), Poland (3), and United States (2). All the eligible studies were cross-sectional. A total of 2, 050 male subjects were included in the meta-analysis. Pyrethroid exposure significantly reduced sperm motility. Region-stratified subgroup analyses revealed that pyrethroid significantly reduced sperm motility among men in Poland and United States, and decreased sperm count among men in Japan. Pyrethroid exposure also reduced sperm concentration among men in Poland but increased sperm concentration among men in the United States. Conclusion: Although the study revealed inconsistent evidence on the detrimental effect of pyrethroids on semen quality, the findings showed that pyrethroids have deleterious potentials on sperm motility, count, and concentration. Studies focusing on the assessment of semen quality in pyrethroid-exposed men, especially at specific varying levels of exposure, and employing prospective cohort studies or controlled cross-sectional designs are recommended.

A systematic review of human biomonitoring studies of 3-phenoxybenzoic acid, a urinary biomarker pyrethroid insecticide exposure, 1997 to 2019

Pyrethroid insecticides are used, for example, in agriculture, indoor environments, and mosquito control programs, resulting in human exposure. Urinary 3-phenoxybenzoic acid (3-PBA) is a nonspecific biomarker for exposure to many pyrethroids. This systematic review identified human biomonitoring studies with 3-PBA that characterize environmental pyrethroid exposures in children and adolescents, pregnant women, and adults or occupational pyrethroid exposures relative to the National Health and Nutrition Examination Survey (NHANES) populations in the United States (US). PubMed, Embase, and SciFinder were searched for "3-phenoxybenzoic acid ", CAS No. 3739-38-6, and urine or urinary or urine level. Duplicate studies and studies meeting the exclusion criteria were removed from the search results based on predetermined exclusion criteria. This screening process identified 57 papers. Twenty-one, thirteen, twenty-two, and eleven manuscripts reported urinary 3-PBA levels in children, pregnant women, environmentally exposed adults, and occupationally exposed adults, respectively. Median 3-PBA levels ranged from 0.2 to 4.7 μg/g creatinine in children (1999-2016), 0.23-1.55 μg/g creatinine in pregnant women (1997-2014), and 0.11-3.34 μg/g creatinine in environmentally exposed adults (1999-2017). 3-PBA levels in occupationally exposed adults were significantly higher than in environmentally exposed populations, ranging from 0.43 to 14 μg/g creatinine (2004-2017). 3-PBA levels in children and adults from the general North American population increased significantly with the sampling year. A decrease in 3-PBA levels was noted in the adult cohorts from PR China and Japan. 3-PBA levels in most studies appeared to be comparable to levels in the NHANES populations; however, some smaller studies had high pyrethroid exposures. Factors contributing to higher 3-PBA levels in the general population included primarily dietary exposures and residential and agricultural pyrethroid applications. These findings demonstrate that pyrethroid exposures are near-ubiquitous worldwide and, in some regions, appear to increase over time. Thus, exposures to pyrethroid insecticides represent a continuing public health concern.

Current status of pesticide effects on environment, human health and it's eco-friendly management as bioremediation: A comprehensive review

Pesticides are either natural or chemically synthesized compounds that are used to control a variety of pests. These chemical compounds are used in a variety of sectors like food, forestry, agriculture and aquaculture. Pesticides shows their toxicity into the living systems. The World Health Organization (WHO) categorizes them based on their detrimental effects, emphasizing the relevance of public health. The usage can be minimized to a least level by using them sparingly with a complete grasp of their categorization, which is beneficial to both human health and the environment. In this review, we have discussed pesticides with respect to their global scenarios, such as worldwide distribution and environmental impacts. Major literature focused on potential uses of pesticides, classification according to their properties and toxicity and their adverse effect on natural system (soil and aquatic), water, plants (growth, metabolism, genotypic and phenotypic changes and impact on plants defense system), human health (genetic alteration, cancer, allergies, and asthma), and preserve food products. We have also described eco-friendly management strategies for pesticides as a green solution, including bacterial degradation, myco-remediation, phytoremediation, and microalgae-based bioremediation. The microbes, using catabolic enzymes for degradation of pesticides and clean-up from the environment. This review shows the importance of finding potent microbes, novel genes, and biotechnological applications for pesticide waste management to create a sustainable environment.

The environmental and occupational influence of pesticides on male fertility: a systematic review of human studies

BACKGROUND

Environment plays a key role in male infertility, changing the incidence in various populations, and pesticides are one of the most studied hazards. The use of the latter has never decreased, jeopardizing the safety of workers and the general population.

OBJECTIVE

Our purpose was to summarize the results of studies discussing the association between pesticides and male fertility.

METHODS

A comprehensive literature search was performed through MEDLINE via PubMed, Scopus, and Web of Science. Only human studies were considered. Semen parameters, and DNA integrity were considered to evaluate the effect of pesticides on men.

RESULTS

A total of 64 studies that investigated their impact in terms of semen parameters (51 studies), chromatin and DNA integrity (25 studies), were included. The most frequently affected parameters were total sperm count sperm motility and morphology, although a reduction in ejaculate volume and concentration occur in several cases. A tangible worsening of semen quality was associated with organochlorines and organophosphates. Furthermore, pesticide exposure, especially pyrethroids, was related to a higher DNA fragmentation index and chromosome aneuploidy in most articles.

CONCLUSION

The epidemiological evidence supports the association between pesticides and male fertility for workers and the exposed population in terms of semen quality, DNA fragmentation and chromosome aneuploidy. This article is protected by copyright. All rights reserved.

Cypermethrin inhibits proliferation of Sertoli cells through AR involving DAB2IP/PI3K/AKT signaling pathway in vitro

Cypermethrin (CP) exhibits anti-androgenic effects through antagonism on androgen receptor (AR) activation. This study was to identify whether AR-mediated disabled 2 interacting protein (DAB2IP)/phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) pathway was involved in CP-induced mouse Sertoli cells (TM4) proliferation disorder. Real-Time Cell Analysis-iCELLigence system was to measure cell proliferation. Bioinformatic analyses were performed to identify AR-regulated genes. Quantitative Real-Time PCR and western blot were to detect the genes and proteins levels in AR-mediated DAB2IP/PI3K/AKT pathway. Results showed CP suppressed TM4 proliferation and the expression of AR. Activation of AR restored the inhibition efficacy of CP on TM4 proliferation. AR regulated DAB2IP expression and phosphorylation levels of PI3K and AKT in CP-exposed TM4 cells. In addition, knockdown of DAB2IP alleviated the inhibition efficacy of CP on cell proliferation and phosphorylation of PI3K and AKT. Taken together, AR was a modulator in CP-induced inhibition of Sertoli cells proliferation by negatively regulating DAB2IP/PI3K/AKT signaling pathway. The study may provide a new insight for the mechanisms of male reproductive toxicity induced by CP.

Environmental and occupational exposures associated with male infertility

The upsurge in male infertility over the last two decades, possibly due to environmental exposure, has raised significant interest, particularly boosted by reports from fertility clinics, which showed that chronic diseases and hereditary or other medical conditions might only partially explain current incidence of male infertility. Both environmental and occupational settings may have a significant role in exposure to complex mixtures of endocrine disruptors (ED), which play a major role in fertility disorders. The aim of this review is to give an insight into the current knowledge on exposure settings which may be associated with male infertility. Our study relied on a systematic search of PubMed, Scopus, and Web of Science for articles published between January 2000 and September 2020. It showed that some well documented factors associated with male infertility include smoking, and physiological disturbances or chronic diseases such as obesity and diabetes, which in turn, may also reflect lifestyle choices and environmental exposures, especially to EDs such as phthalates, bisphenols, pesticides, and flame retardants. However, the number of studies on the aetiology of male infertility is still too low in comparison with the size of affected population. Occupational health follow-ups and medical surveillance do not collect any data on male infertility, even though ED chemicals are part of many technological processes.

Reproductive Health Risks Associated with Occupational and Environmental Exposure to Pesticides

A marked reduction in fertility and an increase in adverse reproductive outcomes during the last few decades have been associated with occupational and environmental chemical exposures. Exposure to different types of pesticides may increase the risks of chronic diseases, such as diabetes, cancer, and neurodegenerative disease, but also of reduced fertility and birth defects. Both occupational and environmental exposures to pesticides are important, as many are endocrine disruptors, which means that even very low-dose exposure levels may have measurable biological effects. The aim of this review was to summarize the knowledge collected between 2000 and 2020, to highlight new findings, and to further interpret the mechanisms that may associate pesticides with infertility, abnormal sexual maturation, and pregnancy complications associated with occupational, environmental and transplacental exposures. A summary of current pesticide production and usage legislation is also included in order to elucidate the potential impact on exposure profile differences between countries, which may inform prevention measures. Recommendations for the medical surveillance of occupationally exposed populations, which should be facilitated by the biomonitoring of reduced fertility, is also discussed.

Concentrations of urinary biomarkers and predictors of exposure to pyrethroid insecticides in young, Polish, urban-dwelling men

Pyrethroid insecticides are a class of pesticides with multiple agricultural and residential applications. However, widespread use of these chemicals may pose a threat to human health. Biomarkers of pyrethroid exposure are frequently detected in populations around the world, but some groups may be underrepresented. Moreover, there is an ongoing debate on factors contributing to pyrethroid burden in humans. To address these problems, we measured urinary biomarkers of pyrethroid exposure in urine samples from 306 young men living in urban area of Łódź, Poland, and gathered questionnaire data to identify predictors of exposure. Limit of detection (LOD) of gas chromatography-mass spectrometry (GC-MS) method was 0.1 ng/mL for all quantified pyrethroid metabolites, namely cis-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid (cis-DCCA), trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid (trans-DCCA), cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropane carboxylic acid (cis-DBCA), and 3-phenoxybenzoic acid (3-PBA). Detection rate ranged from 32% (cis-DBCA) to 76% (trans-DCCA). Concentrations of urinary biomarkers in studied sample were in lower range of these observed in similar studies, with unadjusted geometric means (GMs) of most prevalent biomarkers, trans-DCCA and 3-PBA, equal to 0.268 and 0.228 ng/mL, respectively. As for questionnaire data, the statistical analysis revealed that non-dietary factors, especially dog ownership and pesticide use on household pets, contribute significantly to urinary trans-DCCA and 3-PBA concentrations (p ≤ 0.009). Moreover, a few dietary sources of exposure were identified, such as seeds and nuts consumption for 3-PBA (p < 0.001) and vegetable juice intake for trans-DCCA (p = 0.015). Multivariate analyses further highlighted the importance of non-dietary factors in pyrethroid exposure. Compared to other works, our results confirm widespread exposure to pyrethroids observed in other studies and stress the role of residential pyrethroid use in pyrethroid burden in humans.

Rhamnolipids on Aedes aegypti larvae: a potential weapon against resistance selection

The resistance of Aedes aegypti to chemical insecticides has been reported and our work proposes the use of biosurfactants as an alternative larvicide. We evaluated the effect of rhamnolipids against larvae of pyrethroid-resistant and susceptible A. aegypti strains. Time-mortality and sublethal effects were evaluated via survival analysis and swimming behavior, respectively. Rhamnolipids showed larvicidal effect at all tested concentrations. Rhamnolipids at 300 mg L^-1 killed 100% of both susceptible and resistant larvae within 24 h of exposure and 99% after 30-days stored (pyrethroid-susceptible larvae). Regarding the sublethal effects, the swimming rate was reduced in 50 and 100 mg L^-1 of rhamnolipids in grouped (pyrethroid-susceptible) larvae. Rhamnolipids at 50 mg L^-1 reduced the distance and speed and increased the number of stops and resting time of individualized pyrethroid-susceptible larvae. The larvicidal effect of the rhamnolipids evaluated demonstrates that these compounds represent an alternative to control A. aegypti.

Endocrine disrupting chemicals: Impacts on human fertility and fecundity during the peri-conception period

It is becoming increasingly difficult to avoid exposure to man-made endocrine disrupting chemicals (EDCs) and environmental toxicants. This escalating yet constant exposure is postulated to partially explain the concurrent decline in human fertility that has occurred over the last 50 years. Controversy however remains as to whether associations exist, with conflicting findings commonly reported for all major EDC classes. The primary aim of this extensive work was to identify and review strong peer-reviewed evidence regarding the effects of environmentally-relevant EDC concentrations on adult male and female fertility during the critical periconception period on reproductive hormone concentrations, gamete and embryo characteristics, as well as the time to pregnancy in the general population. Secondly, to ascertain whether individuals or couples diagnosed as sub-fertile exhibit higher EDC or toxicant concentrations. Lastly, to highlight where little or no data exists that prevents strong associations being identified. From the greater than 1480 known EDCs, substantial evidence supports a negative association between exposure to phthalates, PCBs, PBDEs, pyrethroids, organochloride pesticides and male fertility and fecundity. Only moderate evidence exists for a negative association between BPA, PCBs, organochloride pesticides and female fertility and fecundity. Overall fewer studies were reported in women than men, with knowledge gaps generally evident for both sexes for all the major EDC classes, as well as a paucity of female fertility studies following exposure to parabens, triclosans, dioxins, PFAS, organophosphates and pyrethroids. Generally, sub-fertile individuals or couples exhibit higher EDC concentrations, endorsing a positive association between EDC exposure and sub-fertility. This review also discusses confounding and limiting factors that hamper our understanding of EDC exposures on fertility and fecundity. Finally, it highlights future research areas, as well as government, industry and social awareness strategies required to mitigate the negative effects of EDC and environmental toxicant exposure on human fertility and fecundity.

Endocrine-disrupting chemicals and male reproductive health

BACKGROUND

A number of different types of endocrine-disrupting chemicals (EDCs) including bisphenol A, phthalates, pesticides, and other environmental chemicals have been shown to adversely impact upon male reproductive health. Understanding the potential effects of EDCs on male reproductive health may enable the development of novel treatments and early prevention of the effects of EDCs on male infertility and their potential long-term sequelae. This review critically evaluates the research performed in this area and explores potential harmful effects of EDCs in animals and humans, including the possibility of trans-generational transmission.

METHODS

A literature review was conducted using electronic databases using the following terms: 'endocrine disrupt*' OR 'endocrine disruptors' OR 'endocrine disruptor chemicals' OR 'EDC' AND 'sperm*' OR 'spermatozoa' OR 'spermatozoon' OR 'male reproductive health' OR' male fertility'.

MAIN FINDINGS

Several studies have shown that EDCs have a variety of pathophysiological effects. These include failure of spermatogenesis, embryonic development, the association with testicular cancer, and long-term metabolic effects.

CONCLUSIONS

Several studies observe correlations between chemical doses and at least one sperm parameter; however, such correlations are sometimes inconsistent between different studies. Mechanisms through which EDCs exert their pathophysiological effects have not yet been fully elucidated in human studies.

Potential Increased Risk of Trisomy 18 Observed After a Fertilizer Warehouse Fire in Brazos County and TX

Background: In this paper, we aimed to investigate the potential impacts of a fire accident in a fertilizer warehouse on chromosomal anomalies, including Trisomy 21 (T21) and Trisomy (T18) among pregnancies in Brazos County, Texas. We conducted an observational study in Brazos County, TX, with all patients of T18 and T21 cases in the live births in Brazos County between 2005–2014. The prevalence of T18 and T21 before, during, and after the accident in Brazos County were calculated and compared. The Standardized Morbidity Ratio (SMR) was applied to compare the prevalence of T18 and T21 in Brazos County to the statewide prevalence in Texas after adjusting for maternal race and age. Compared with statewide risk, the risk of T18 during the impacted years in Brazos county was found to be significantly higher (SMR = 5.0, 95% Confidence Interval(CI): 2.19–9.89), while there was no significant difference before (SMR = 0.77, 0.13–2.54) and after the accident (SMR = 0.71, 0.12–2.36). However, the prevalence of T21 during the impacted years was not significantly different from those before or after the accident. This study conclusively suggests that this fertilizer fire may be related to the increased prevalence of T18 in Brazos County, though the findings warrant further investigation.

Effects of environmental pyrethroids exposure on semen quality in reproductive-age men in Shanghai, China

BACKGROUND

Animal experiments have revealed that pyrethroids (PYRs) exposure could affect semen quality, however evidence on humans being is limited and controversial.

OBJECTS

To explore the potential effects of environmental PYRs exposure on semen quality in reproductive age men.

METHODS

We conducted a cross-sectional study of 346 men who planned to conceive and addressed to hospital for preconception examination. PYRs exposure was assessed by analyzing PYRs urinary metabolites [3-phenoxybenzoic acid (3PBA), trans- and cis-3-(2,2-Dichlorovinyl) -2,2-dimethylcy clopropane carboxylic acid (TDCCA and CDCCA)] levels using gas chromatography-mass spectrometry. Semen quality was assessed by a computer-aided semen analyzer.

RESULTS

For a detection rate of 99.7%, 76.6%, and 22.0%, the median levels (μg/g creatinine) of PYRs metabolites were 0.46 for 3PBA, 0.38 for TDCCA and under detection limit for CDCCA. Linear regression models found negative associations between 3PBA and sperm morphology (β = -2.12, 95% CI: -4.02 to -0.22) as well as between TDCCA and log-transformed total sperm count (β = -0.09, 95% CI: -0.16 to -0.01). In logistic regression models, men with the highest quartile of 3PBA had higher risk of poor semen quality (having below-reference semen parameter, OR = 2.40, 95% CI: 1.26 to 4.54; having below-reference sperms morphology, OR = 3.08, 95% CI: 1.10 to 8.60) compared to men in the lowest quartile.

CONCLUSIONS

Our study suggests that environmental PYRs exposure might adversely affect semen parameters of reproductive age men in Shanghai, China. Further studies are needed to confirm our findings and demonstrate a causal relationship between PYRs exposure and semen quality.

Paternal occupational exposure to chemicals and secondary sex ratio: results from the Japan Environment and Children's Study

BACKGROUND

Declining proportions of male births have been reported in several industrialised countries. Previous reports have shown that exposure to certain chemical substances might influence the secondary sex ratio (SSR). We assessed the associations between paternal occupational exposure to chemicals and the SSR of their children using the Japan Environment and Children's Study (JECS), a large-scale birth cohort study.

METHODS

Data on paternal occupational exposure to various agents and other covariates were collected using a self-administered questionnaire to partners of pregnant female participants enrolled in the JECS. After adjusting for potential confounders, multivariable modified Poisson regression models were used to evaluate associations between paternal occupational exposures and the SSR of their children. This study was registered in the UMIN Clinical Trials Registry, number UMIN000030786.

FINDINGS

The JECS study gathered data on 103 062 pregnancies, 104 065 fetuses, and 51 898 partners of pregnant women. Among 50 283 children with data on paternal occupational exposures, 25 657 were male and 24 626 were female. The proportion of boys whose fathers were regularly occupationally exposed to insecticides was 0·445 (males, n=293; females, n=366; 95% CI 0·406-0·483), which was lower than the proportion of boys whose fathers were not exposed to insecticides. After adjusting for confounding factors, regular paternal occupational exposure to insecticides (adjusted relative risk 0·86, 95% CI 0·78-0·96) and medical disinfectants (0·95, 0·90-1·00) were significantly associated with lower SSRs among their offspring compared with the offspring of fathers not exposed to these substances.

INTERPRETATION

A declining proportion of boys could potentially be due to fathers working in environments in which they are exposed to chemicals. The associations between poorer semen quality and levels of reproductive and thyroid hormones require investigation.

FUNDING

Ministry of the Environment of Japan.

Pesticide interactions and risks of sperm chromosomal abnormalities

Disentangling the separate and synergistic effects of chemicals poses methodological challenges for accurate exposure assessment and for investigating epidemiologically how chemicals affect reproduction. We investigated combined exposures to ubiquitous contemporary use pesticides, specifically organophosphates (OP) and pyrethroids (PYR), and their association with germ cell abnormalities among adult men. Fluorescence in situ hybridization was used to determine disomy in sperm nuclei and urine was analyzed for concentrations of PYR metabolites (3-phenoxybenzoic acid; 3PBA) and OP dialkyl phosphate (DAP) metabolites. Incidence rate ratios using Poisson models were estimated for each disomy type by exposure quartile of DAP metabolites and 3PBA, controlling for confounders. The shape of the associations between PYRs, OPs and disomy were frequently nonmonotonic. There were consistent interactions between OP and PYR metabolite concentrations and the risk for sperm abnormalities. Taking both chemicals into account simultaneously resulted in quantitatively different associations than what was reported previously for OPs and PYRs separately, demonstrating the importance of modeling multiple concentrations simultaneously. Methods investigating interactions using Poisson models are needed to better quantify chemical interactions and their effects on count-based health outcomes, the importance of which was shown here for germ cell abnormalities.

FDA-approved medications that impair human spermatogenesis

We herein provide an overview of the single-ingredient U.S. Food and Drug Administration (FDA)-approved drugs that affect human spermatogenesis, potentially resulting in a negative impact on male fertility. To provide this information, we performed an in-depth search of DailyMed, the official website for FDA-approved drug labels. Not surprisingly, hormone-based agents were found to be the drugs most likely to affect human spermatogenesis. The next category of drugs most likely to have effects on spermatogenesis was the antineoplastic agents. Interestingly, the DailyMed labels indicated that several anti-inflammatory drugs affect spermatogenesis, which is not supported by the peer-reviewed literature. Overall, there were a total of 65 labels for drugs of various classes that showed that they have the potential to affect human sperm production and maturation. We identified several drugs indicated to be spermatotoxic in the drug labels that were not reported in the peer-reviewed literature. However, the details about the effects of these drugs on human spermatogenesis are largely lacking, the mechanisms are often unknown, and the clinical impact of many of the findings is currently unclear. Therefore, additional work is needed at both the basic research level and during clinical trials and post-marketing surveillance to fill the gaps in the current knowledge. The present findings will be of interest to physicians and pharmacists, researchers, and those involved in drug development and health care policy.

Pyrethroid epidemiology: a quality-based review

Pyrethroids are commonly used around the home and in agricultural production to control insects. Human contact to one or more pyrethroid insecticides is likely. Numerous epidemiology studies have evaluated the association between health outcomes in humans and pyrethroid exposure. The purpose of this review was to identify and evaluate the quality of pyrethroid-related epidemiology studies that addressed chronic health effects, and compare findings with animal toxicology studies. We evaluated the quality of 61 studies published between 2000 and 2016 by using elements of outcome, exposure metric, exposure level, and study design. None of the 61 publications demonstrated strong quality for all elements. A few of the outcome measures were strong, particularly those relying upon medical diagnoses. Most of the pyrethroid epidemiology studies used a poor exposure metric, relying upon a single sample of pyrethroid urinary metabolites, which is subject to misclassification of past exposures. In addition, many studies were a cross-sectional design, preventing an evaluation of the temporality of the exposure-disease association. Furthermore, none of the effects observed in the epidemiological literature was concordant with toxicological effects noted in extensive testing of pyrethroids in animals. In order to provide more robust data on potential health outcomes from low dose exposure to pyrethroid insecticides, future epidemiological studies should fully characterize an adverse outcome, include exposure validation components, and quantify exposure over time.

Off-line microextraction by packed sorbent combined with on solid support derivatization and GC-MS: Application for the analysis of five pyrethroid metabolites in urine samples

A novel, fast and eco-friendly analytical method using microextraction by packed sorbent coupled to large volume injection-gas chromatography-mass spectrometry (MEPS-LVI-GC-MS) was developed for the determination of five pyrethroid metabolites (cis-2,2-dimethyl-3-(2-chloro-3,3,3-trifluoro-1-propenyl)-cyclopropanecarboxylic acid, cis/trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acids, cis-(2,2-dibromovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid and 3-phenoxybenzoic acid) in human urine. MEPS was performed off-line using a manually-operated semiautomatic syringe (eVol), and several parameters including the sample pH, extraction sorbent, washing solvent, volume and type of elution solvent and number of draw-eject cycles were optimized. Analytes were extracted from enzymatically hydrolyzed urine using a C18 solid phase with subsequent simultaneous derivatization and elution with a mixture of 1,1,1,3,3,3-hexafluoroisopropanol and diisopropylcarbodiimide in n-hexane (on-line derivatization). The optimized method was validated, with linearity established from 0.05 to 25ngmL^-1 and R values > 0.99. Obtained quantification limits were in the range of 0.06-0.08ngmL^-1, and the precision expressed as relative standard deviation (RSD) was below 14% for all of the analytes. The method was cross-validated with a reference approach based on liquid-liquid extraction-gas chromatography-mass spectrometry (LLE-GC-MS) by analyzing 21 urine samples.

Temporal variability of pyrethroid metabolite levels in bedtime, morning, and 24-h urine samples for 50 adults in North Carolina

Pyrethroid insecticides are widely used to control insects in both agricultural and residential settings worldwide. Few data are available on the temporal variability of pyrethroid metabolites in the urine of non-occupationally exposed adults. In this work, we describe the study design and sampling methodology for the Pilot Study to Estimate Human Exposures to Pyrethroids using an Exposure Reconstruction Approach (Ex-R study). Two major objectives were to quantify the concentrations of several pyrethroid metabolites in bedtime, first morning void (FMV), and 24-h urine samples as concentration (wet weight), specific-gravity (SG) corrected, creatinine (CR) corrected, and excretion rate values for 50 Ex-R adults over a six-week monitoring period and to determine if these correction approaches for urine dilution reduced the variability of the biomarker levels. The Ex-R study was conducted at the United States Environmental Protection Agency's Human Studies Facility in Chapel Hill, North Carolina USA and at participants' homes within a 40-mile radius of this facility. Recruitment of participants and field activities occurred between October 2009 and May 2011. Participants, ages 19-50 years old, provided daily food, activity, and pesticide-use diaries and collected their own urine samples (bedtime, FMV, and 24-h) during weeks 1, 2, and 6 of a six-week monitoring period. A total of 2503 urine samples were collected from the study participants. These samples were analyzed for the pyrethroid metabolites 3-phenoxybenzoic acid (3-PBA), cis/trans-3-(2,2-dichlorovinyl)-2,2-dimethyl-cyclopropane carboxylic acid (cis/trans-DCCA), and 2-methyl-3-phenylbenzoic acid (MPA) using high performance liquid chromatography/tandem mass spectrometry. Only 3-PBA was frequently detected (>50%) in the adult urine samples. Median urinary 3-PBA levels were 0.88 ng/mL, 0.96 ng/mL-SG, 1.04 ng/mg, and 1.04 ng/min for concentration, SG-corrected, CR-corrected, and excretion rate values, respectively, across all urine samples. The results showed that median urinary 3-PBA concentrations were consistently the lowest in FMV samples (0.77 ng/mL, 0.68 ng/mL-SG, 0.68 ng/mg, and 0.58 ng/min) and the highest in 24-h samples (0.92 ng/mL, 1.06 ng/mL-SG, 1.18 ng/mg, and 1.19 ng/min) across all four methods. Intraclass correlation coefficient (ICC) estimates for 3-PBA indicated poor reproducibility (<0.22) for all urine sample types and methods over a day, week, and six weeks. Correcting for urine sample dilution, based on either SG, CR or urine output, introduced additional measurement variability both between- and within-individuals. These results indicate that a single measure of urinary 3-PBA was not sufficient to characterize average exposure regardless of sample type, correction method, and time frame of collection. In addition, the study results can be used to inform the design of exposure characterization strategies in relevant environmental epidemiology studies in the future.

The association between environmental exposure to pyrethroids and sperm aneuploidy

The aim of the present study is to determine whether the environmental exposure to pyrethroids was associated with males sperm chromosome disomy. The study population consisted of 195 men who attended the infertility clinic for diagnostic purposes and who had normal semen concentration of 20-300×10(6) mL(-1) or slight oligozoospermia (semen concentration of 15-20×10(6) mL(-1)) (WHO, 1999). Participants were interviewed and provided a semen sample. The pyrethroids metabolites: 3-phenoxybenzoic acid (3PBA), cis-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid (CDCCA), trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid (TDCCA) and cis-2,2-dibromovinyl-2,2-dimethylcyclopropane-1-carboxylic acid (DBCA) were analysed in the urine using a validated gas chromatography ion-tap mass spectrometry method. Sperm aneuploidy was assessed using multicolor FISH (DNA probes specific for chromosomes X, Y, 18, 13, 21). Our results showed that CDCCA >50th percentile was associated with disomy of chromosome 18 (p=0.05) whereas the level of TDCCA in urine >50th percentile was related to XY disomy (p=0.04) and disomy of chromosome 21 (p=0.05). Urinary 3PBA level ⩽50 and >50 percentile was related to disomy of sex chromosomes: XY disomy (p=0.05 and p=0.02 respectively), Y disomy (p=0.04 and 0.02 respectively), disomy of chromosome 21 (p=0.04 and p=0.04 respectively) and total disomy (p=0.03 and p=0.04 respectively). Additionally disomy of chromosome 18 was positively associated with urinary level of 3PBA >50 percentile (p=0.03). The results reported here are found that pyrethroids may be a sperm aneugens. These findings may be of concern due to increased pyrethroid use and prevalent human exposure.

The relationship between exposure to air pollution and sperm disomy

The causes of the chromosome abnormalities have been studied for decades. It has been suggested that exposure to various environmental agents can induce chromosomal abnormalities in germ cells. This study was designed to address the hypothesis that exposure to specific air pollutants increases sperm disomy. The study population consisted of 212 men who were attending an infertility clinic for diagnostic purposes. They represented a subset of men in a multicenter parent study conducted in Poland to evaluate environmental factors and male fertility. Sperm aneuploidy for chromosomes 13, 18, 21, X, and Y was assessed using multicolor fluorescence in situ hybridization. Air quality data were obtained from the AirBase database. After adjusting for age, smoking, alcohol consumption, temperature (90 days), season, past diseases, abstinence interval, distance from the monitoring station, concentration, motility and morphology, positive associations were observed between exposure to PM2.5 and disomy Y (P = 0.001), sex chromosome disomy (P = 0.05) and disomy 21 (P = 0.03). Exposure to PM10 was associated with disomy 21 (P = 0.02). Conversely, exposure to ozone, CO, SO2, and NOx did not affect sperm aneuploidy. A separate analysis conducted among men who were nonsmokers (n = 117) showed that the relationship between PM2.5 and disomy Y and disomy 21 remained significant (P = 0.01, P = 0.05, respectively). The present findings indicate that exposure to air pollution induces sperm aneuploidy.

Sperm aneuploidy in infertile male patients: a systematic review of the literature

Males with abnormal karyotypes and subgroups of fertile and infertile males with normal karyotypes may be at risk of producing unbalanced or aneuploid spermatozoa. Biological, clinical, environmental and other factors may also cause additional sperm aneuploidy. However, increased risk of sperm aneuploidy is directly related to chromosomally abnormal embryo production and hence to poor reproductive potential. This systemic literature review focuses on the identification of these males because this is an essential step in the context of assisted reproduction. This research may allow for a more personalised and, hence, more accurate estimation of the risk involved in each case, which in turn will aid genetic counselling for affected couples and help with informed decision-making.