Urinary concentrations and determinants of glyphosate and glufosinate in pregnant Canadian participants in the MIREC study.

BACKGROUND: Glyphosate is the most widely applied herbicide in agriculture. Glufosinate is a broad spectrum herbicide used to manage glyphosate-resistant weeds. Despite the widespread use of these herbicides, biomonitoring data - which inform risk assessment and management - are sparse. OBJECTIVES: To identify determinants of urinary concentrations of these herbicides and their metabolites in pregnancy. METHODS: We measured urinary concentrations of glyphosate, glufosinate, and their primary metabolites aminomethylphosphonic acid (AMPA) and 3-methylphosphinicopropionic acid (3-MPPA) in a single spot urine specimen collected during the first trimester of pregnancy from the Maternal-Infant Research on Environmental Chemicals (MIREC) study. MIREC recruited about 2000 pregnant women from 10 Canadian cities between 2008 and 2011. We used UItra-Performance Liquid Chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) with sensitive limits of detection to quantify analyte concentrations. We examined urinary concentrations according to maternal sociodemographics, sample collection characteristics, reported pesticide use, and consumption of fruits, vegetables, legumes, and grain products. We used ANOVA models with specific gravity-standardized chemical concentrations as the dependent variable to determine associations with maternal and sample determinants. RESULTS: Among women with biobanked urine samples (n = 1829-1854), 74% and 72% had detectable concentrations of glyphosate and AMPA, respectively. In contrast, one and six percent of women had detectable concentrations of glufosinate and 3-MPPA, respectively. The specific gravity-standardized geometric mean (95% CI) concentrations of glyphosate and AMPA were 0.112 (0.099-0.127) µg/L and 0.159 (0.147-0.172) µg/L, respectively. We observed a dose-response relationship between consumption of whole grain bread and higher urinary glyphosate concentrations. Season of urine collection and self-reported pesticide use were not associated with increased concentrations of any analyte. CONCLUSIONS: We detected glyphosate and AMPA in the majority of pregnant women from this predominantly urban Canadian cohort. Diet was a probable route of exposure.

Prevalence of Use and Perceived Effectiveness of Medical, Surgical, and Alternative Therapies for Endometriosis Pain in Canadians.

OBJECTIVES: To describe the use and perceived effectiveness of medical, surgical, and alternative therapies (e.g., diet, exercise, heat, cannabis, etc.) in managing endometriosis-associated pain in Canadians. METHODS: A cross-sectional online survey was distributed via The Endometriosis Network Canada (TENC) from February to March 2021. Canadians aged 18-50 years with diagnosed or suspected endometriosis were eligible to participate. RESULTS: A total of 434 survey responses were included, and 93.8% of respondents reported that they used at least 1 alternative therapy in the past 6 months for endometriosis-associated pain. Respondents used an array of medical (2.3/6 months), surgical (1.7/lifetime), and alternative therapies (6.9/6 months) to manage their pain, yet 61.9% of respondents did not feel it was adequately managed. The most common alternative therapies were heat, meditation/mindfulness/rest, and diet. CONCLUSION: Alternative therapies were commonly used by Canadians living with endometriosis to manage pain. Cannabis and heat were perceived as the most effective alternative therapies. Here, we gain a better understanding of alternative therapies that can provide an additional therapeutic avenue that clinicians and people living with endometriosis may wish to discuss and explore.

A critical appraisal of the circulating levels of differentially expressed microRNA in endometriosis†.

Endometriosis is a common gynecological condition characterized by estrogen dependence, chronic pelvic pain, infertility, and diagnostic delay of between 5.4 and 12 years. Despite extensive study, no biomarker, either alone or in combination with other markers, has proven superior to laparoscopy for the diagnosis of endometriosis. Recent studies report that circulating levels of differentially expressed microRNA (miRNA) in women with endometriosis compared with controls are potential diagnostic tools. However, the lack of replication and absence of validated differential expression in novel study populations have led some to question the diagnostic value of miRNA. To elucidate potential reasons for the lack of replication of study results and explore future directions to enhance replicability of circulating miRNA results, we carried out an electronic search of the miRNA literature published between 2000 and 2020. Eighteen studies were identified in which 63 different miRNAs were differentially expressed in the circulation of women with endometriosis compared with controls. However, the differential expressions of only 14 miRNAs were duplicated in one or more studies. While individual miRNAs lacked diagnostic value, miRNA panels yielded sensitivity and specificity equal to or better than laparoscopy in five studies. Important differences in study design, sample processing, and analytical methods were identified rendering direct comparisons across studies problematic and could account for the lack of reproducibility of study results. We conclude that while the results of miRNA studies to date are encouraging, refinements to study design and analytical methods should enhance the reliability of circulating miRNA for the diagnosis of endometriosis.

Appraisal of systematic reviews on interventions for postpartum depression: systematic review.

BACKGROUND: Postpartum depression (PPD) is a highly prevalent mental health problem that affects parental health with implications for child health in infancy, childhood, adolescence and beyond. The primary aim of this study was to critically appraise available systematic reviews describing interventions for PPD. The secondary aim was to evaluate the methodological quality of the included systematic reviews and their conclusions. METHODS: An electronic database search of MEDLINE, Embase, and the Cochrane Library from 2000 to 2020 was conducted to identify systematic reviews that examined an intervention for PPD. A Measurement Tool to Assess Systematic Reviews was utilized to independently score each included systematic review which was then critically appraised to better define the most effective therapeutic options for PPD. RESULTS: Of the 842 studies identified, 83 met the a priori criteria for inclusion. Based on the systematic reviews with the highest methodological quality, we found that use of antidepressants and telemedicine were the most effective treatments for PPD. Symptoms of PPD were also improved by traditional herbal medicine and aromatherapy. Current evidence for physical exercise and cognitive behavioural therapy in treating PPD remains equivocal. A significant, but weak relationship between AMSTAR score and journal impact factor was observed (p = 0.03, r = 0.24; 95% CI, 0.02 to 0.43) whilst no relationship was found between the number of total citations (p = 0.27, r = 0.12; 95% CI, - 0.09 to 0.34), or source of funding (p = 0.19). CONCLUSION: Overall the systematic reviews on interventions for PPD are of low-moderate quality and are not improving over time. Antidepressants and telemedicine were the most effective therapeutic interventions for PPD treatment.

Real-world characteristics of women with endometriosis-related pain entering a multidisciplinary endometriosis program.

BACKGROUND: Women with endometriosis are commonly treated by their sole provider. In this single-provider model of care, women frequently report long diagnostic delays, unresolved pelvic pain, multiple laparoscopic surgeries, sequential consultations with numerous providers, and an overall dissatisfaction with care. The emergence of multidisciplinary endometriosis centers aims to reduce diagnostic delays, improve pain management, and promote patient satisfaction; however, baseline data at the time of presentation to a multidisciplinary center are lacking. METHODS: A real-world, retrospective, single-site, cross-sectional study of women with surgically confirmed and/or clinically diagnosed endometriosis generated baseline data for a planned longitudinal assessment of multidisciplinary care of endometriosis. The primary objective was to determine the proportion of patients experiencing mild, moderate, or severe pain for dysmenorrhea, non-menstrual pelvic pain (NMPP), and dyspareunia at entry into a multidisciplinary endometriosis clinic. Also explored were relationships between pain scores and clinical endpoints obtained from electronic medical records. RESULTS: More than half (59%) of the study participants (n = 638) reported experiencing pelvic pain for ≥ 5 years. Pain intensity was highest for patients reporting dysmenorrhea, followed by NMPP, and dyspareunia. Significant correlations were observed between total pelvic pain and patient age (r = -0.22, p < 0.001, n = 506) and number of previous healthcare providers (r = 0.16, p = 0.006, n = 292); number of previous providers and duration of pain (r = 0.21, p = < 0.0001, n = 279); and duration of pain and years since diagnosis (r = 0.60, p < 0.001, n = 302). Mean pain scores differed significantly by age group for dysmenorrhea (p < 0.001), NMPP (p = 0.005), and total pelvic pain (p < 0.001), but not for dyspareunia (p = 0.06), with the highest mean pain scores reported among those < 30 years of age. CONCLUSION: These real-world data indicate that in the single-provider model of care, unresolved pelvic pain is common among women with endometriosis. Alternative care models, including a multidisciplinary approach, need to be evaluated for improvements in clinical outcomes. These data also highlight the importance of addressing NMPP, which may be particularly troublesome for patients.

Quality appraisal of systematic reviews on methods of labour induction: a systematic review.

PURPOSE: Induction of labour has become more common over the last decade, together with an increase in the number of systematic reviews of the subject. However, with multiple systematic reviews it is necessary to evaluate the methodological rigor to ensure the reliability of conclusions and recommendations for clinical practice. Therefore, the aim of this study was to appraise the quality of systematic reviews that examined the efficacy and/or safety of labour induction methods. METHODS: An electronic search of MEDLINE, Embase, and the Cochrane Library from 2000 to 2020 was conducted. Study selection, data extraction and quality assessment were conducted using A Measurement Tool to Assess Systematic Reviews (AMSTAR) by two independent reviewers, in duplicate. RESULTS: The search identified 387 publications, of which 48 studies (13%) met the a priori inclusion criteria. No significant relationships were found between study quality and number of citations, journal impact factor, or publication year. CONCLUSION: Methodological quality for systematic reviews on the induction of labour were ranked as moderate with no significant changes in quality over the past 2 decades. Publication characteristics are not significantly associated with methodological quality, indicating that healthcare professionals should critically appraise studies before applying them to practice.

Do stressful life events during pregnancy modify associations between phthalates and anogenital distance in newborns?

Anogenital distance (AGD) has been used as a marker of fetal androgen action to identify endocrine disrupting chemicals. A US study (TIDES) has reported that the association between some phthalates and reduced AGD in males was only apparent in sons of mothers reporting no stressful life events (SLEs) during pregnancy. The objective of the current study was to examine the potential modifying effect of SLEs and their subjective impact on associations between prenatal phthalates and AGD. First trimester urines from the MIREC Study were analysed for phthalate metabolites and AGD was measured in neonates. Post-delivery, the women answered questions on SLEs during the pregnancy. Women reporting 1 or more SLEs during pregnancy were considered a "higher stressor" group, whereas women reporting no SLEs or who reported a SLE that was perceived as not at all stressful were considered a "lower stressor" group. Multivariable linear regression models were fit stratified by stressor group. Maternal stressor, AGD and phthalates results were available for 153 females and 147 males. A summary measure of androgen-disrupting phthalates (Σ AD) was associated with significantly longer AGDs in females from the higher stressor group. These effect sizes were increased when the perceived impact was restricted to moderately or very much stressful. In males, all phthalates were associated with longer anopenile distance (APD), regardless of stressor group; however, higher Σ AD was associated with significantly longer APD in the lower stressor group. In contrast to the TIDES study, we did not observe shorter AGDs in male infants prenatally exposed to di-(2-ethylhexyl) phthalates, regardless of maternal stressor level. In conclusion, we were unable to replicate the findings of the TIDES study, but did find some evidence that prenatal SLEs may modify associations between phthalates and female AGD. Further research with other populations and measures of prenatal stress may shed more light on whether prenatal stress is an important effect modifier of associations between phthalates (or other chemicals) and anogenital distance.

MicroRNA expression pattern differs depending on endometriosis lesion type.

MicroRNA (miRNA), noncoding segments of RNA involved in post-transcriptional regulation of protein expression are differentially expressed in eutopic endometrium of women with and without endometriosis compared to endometriotic lesions. However, endometriotic lesion types are known to be biochemically distinct and therefore hypothesized that miRNAs are differentially expressed in endometriomas compared to peritoneal and deep-infiltrating lesions. Therefore, endometrial biopsies and ectopic implants from women (n = 38) undergoing laparoscopic surgery for chronic pelvic pain were collected. Samples of endometriomas, peritoneal or deep-infiltrating lesions were selected from our tissue bank for study participants who exclusively had only one lesion type noted on their surgical report. Quantitative real-time polymerase chain reaction for miR-9, miR-21, miR-424, miR-10a, miR-10b, and miR-204 was performed. miR-204 expression was significantly lower (P = 0.0016) in the eutopic endometrium of women with endometriosis compared to controls. Relative expression of miR-21, miR-424, and miR-10b differed significantly (P < 0.05) across endometriotic lesion types. Finally, all miRNAs isolated from endometriomas, peritoneal and deep-infiltrating lesions studied were differentially expressed compared to matched eutopic endometrium samples. We therefore conclude that miRNA expression in the eutopic endometrium from women with endometriosis differs from symptomatic controls. Moreover, miRNA expression pattern is dependent on the endometriotic lesion type studied. We suggest that identification of different miRNA expression patterns for endometriomas, peritoneal and deep-infiltrating lesions could contribute to individualized patient care for women with endometriosis.

Identification of microRNAs as potential markers of ovarian toxicity.

Exposure to environmental toxicants has been associated with ovarian dysfunction yet sensitive biomarkers of adverse effect are lacking. We previously demonstrated that cigarette smoke exposure induced decreased relative ovarian weight, increased follicle loss and granulosa cell autophagy in mice. We postulate that cigarette smoke exposure will induce changes in the epigenome that can be used to reveal potential sensitive biomarkers of ovarian toxicity. Therefore, we evaluated differences in expression of 940 microRNAs (miRNAs), environmentally responsive small non-coding genes that regulate expression of genes at the post-transcriptional level, in ovarian tissue from 8-week-old female C57BL/6 mice exposed to room air or cigarette smoke 5 days per week for 8 weeks. A total of 152 miRNAs were dysregulated in expression, 17 of which were examined with quantitative polymerase chain reaction analysis. Using an online miRNA database tool, complete lists of predicted miRNA gene targets were generated, 12 of which were measured for their expression levels with quantitative polymerase chain reaction. An online bioinformatics resource database, DAVID generated functional classification lists of the target genes and their associated biological pathways. Results of the present pilot study suggest that miR-379, miR-15b, miR-691, miR-872 and miR-1897-5p are potentially useful markers of ovarian toxicity and dysfunction. Examination of the expression pattern of the target mRNA for these miRNA species demonstrated that cigarette smoke exposure induced significant changes that affect mitogen-activated protein kinase signaling pathways. We therefore suggest that miRNAs could serve as sensitive markers of ovarian toxicity and elucidate affected pathways.

Human exposure to environmental contaminants and congenital anomalies: a critical review.

Congenital anomalies are an important cause of infant mortality and disability. Developmental exposure to environmental contaminants is thought to increase the risk for congenital anomalies. Herein, we describe a critical review of the literature conducted between February and March 2014 yielding 3057 references from which 97 unique relevant articles published from 2003 through 2014 were evaluated. Common congenital anomalies including hypospadias, cryptorchidism, anogenital distance (AGD), congenital heart defects and oral clefts were well represented in the literature whereas other outcomes such as neural tube defects, limb deficiency defects and gastroschisis were rarely described. While definitions used for congenital anomalies and methods of ascertainment were usually consistent across studies, inconsistencies were frequently found in grouping of different congenital heart defects. Despite strong links between some congenital anomalies and parental occupation, these studies are unable to provide clear insight into the specific chemicals responsible owing to lack of direct measures of exposure. In comparison, data are mixed for contaminant exposures at concentrations representative of results from contemporary biomonitoring studies. Of the environmental contaminants studied, the association between phthalate exposures and developmental abnormalities of the male reproductive tract received the greatest attention. Important limitations of the literature studied relate to adequacy of sample size, absence of or weaknesses in exposure assessment methodologies, failure to account for biological plausibility and grouping of congenital anomalies with divergent mechanisms. We conclude that the literature is inadequate at this time to support a conclusion that exposure to environmental contaminants are or are not associated with increased risks for congenital anomalies in the general population.

Concentrations of persistent organic pollutants in maternal and cord blood from the maternal-infant research on environmental chemicals (MIREC) cohort study.

BACKGROUND: Pregnant women are an especially important population to monitor for environmental exposures given the vulnerability of the developing fetus. During pregnancy and lactation chemical body burdens may change due to the significant physiological changes that occur. Developmental exposures to some persistent organic pollutants (POPs) have been linked with adverse health outcomes. METHODS: First trimester maternal and cord blood plasma concentrations of several POPs including polychlorinated biphenyls (PCBs), organochlorine pesticides (OCs), polybrominated diphenyl ethers (PBDE)s and perfluoroalkyl substances (PFASs) were measured in samples from 1983 pregnant women enrolled in the Maternal-Infant Research on Environmental Chemicals (MIREC) cohort. Predictors of exposure were also identified. RESULTS: In maternal plasma, there was >90 % detection for the perfluoroalkyl substances (PFASs) perfluorooctanoic acid (PFOA), perfluoroctane sulfonate (PFOS), perfluorohexane sulfonate (PFHxS), and dichlorodiphenyldichloroethylene (DDE), oxychlordane and PCB 138 and 153. Cord blood plasma had much lower detection rates with low or very limited detection for most PCBs and PBDEs. The PFASs were the most frequently detected (23-64 %) chemical class in cord plasma. In a subset of 1st and 3rd trimester paired samples, PFAS concentrations were found to be strongly correlated and had ICCs ranging from 0.64 (PFOA) to 0.83 (PFHxS). The cord:maternal plasma concentration ratios ranged from 0.14 (PFOS) to 0.87 (oxychlordane, lipid adjusted). Similar to other studies, we found parity, maternal age, income, education, smoking status, pre-pregnancy BMI and fish consumption to be significant predictors for most chemicals. Those participants who were foreign-born had significantly higher concentrations of organochlorinated pesticides and PCBs. CONCLUSIONS: In the MIREC study, multiple chemical contaminants were quantified in the plasma of pregnant women. In cord plasma PFOA had the highest detection rate. However, compared to other Canadian and international population studies, the MIREC participants had lower contaminant concentrations of these substances.

Effects of in vitro exposure to butylparaben and di-(2 ethylhexyl) phthalate, alone or in combination, on ovarian function.

Parabens and phthalates are commercial chemicals widely used in the manufacture of industrial and consumer products frequently found as contaminants in biological fluids. We evaluated the effects of di-(2-ethylhexyl) phthalate (DEHP) (ranging from 10(-9) to 10(-7) m [1-100 nm; 0.39-39 ng ml(-1) ]) and butylparaben (BP) (ranging from 10(-8) to 10(-5) m [10 nm-10 µm; 1.9 ng ml(-1) to 1.9 µg ml(-1) ]), alone and in combination, on isolated mouse preantral follicle and human granulosa cell (hGC) cultures to study direct effects on follicle growth and ovarian steroidogenesis. Our results revealed that, in follicle culture, DEHP and BP attenuate estradiol output but only when present together. DEHP decreases progesterone concentrations in the spent media of hGC cultures, an effect that was attenuated when BP was added together with DEHP. Although changes in steroidogenesis were observed, no effects on follicular development or survival were noted in the culture systems. We suggest that BP and DEHP act with additive effect to decrease estradiol production whereas at later stages of follicle development BP blocks the effect of DEHP in hGCs resulting in decreased progesterone output. Taken together our results suggest that DEHP and BP adversely affect steroidogenesis from the preantral stage onward and the effects of these chemicals are both stage-dependent and modified by co-exposure. Copyright © 2016 John Wiley & Sons, Ltd.

Cigarette smoke exposure triggers the autophagic cascade via activation of the AMPK pathway in mice.

We previously demonstrated that cigarette smoke (CS) exposure decreases primordial follicle counts and induces autophagy in ovarian granulosa cells in preference to apoptosis. Therefore, the objective of this study was to investigate molecular targets underlying smoke-induced activation of the reparative autophagy pathway in the ovary. Briefly, ovarian homogenates were prepared from adult female mice exposed to mainstream CS twice daily for 8 wk, using a whole-body exposure system. A gene array revealed that CS exposure induced a greater than 2-fold significant increase in the expression of proautophagic genes Cdkn1b, Map1lc3a, Bad, and Sqstm1/p62. A significant increase in Prkaa2, Pik3c3, and Maplc31b expression, as well as a significant decrease in Akt1 and Mtor expression, was detected by quantitative PCR. The 5'-AMP-activated protein kinase catalytic subunit (AMPK) alpha1 + alpha2 and ATG7 protein expression was significantly increased, whereas AKT1, mTOR, CDKN1B/p27, and CXCR4 proteins were significantly decreased in CS exposed versus control ovaries. Up-regulation of AMPK alpha1 + alpha2, a known initiator of autophagic signaling, and ATG7 further suggests activation of the autophagy cascade. Two prosurvival factors, AKT and mTOR, were decreased in expression, an outcome that favors induction of the autophagy pathway, whereas decreased levels of CDKN1B is suggestive of cell cycle dysregulation. In summary, our data suggest that CS exposure induces ovarian follicle loss through induction of the autophagic cascade via the AMPK pathway together with inhibition of antiautophagic markers AKT and mTOR. We further postulate that toxicant-induced dysregulation of reparative autophagy is a novel pathway central to impaired follicle development and subfertility.

Estrogen induced changes in uterine brain-derived neurotrophic factor and its receptors.

STUDY QUESTION: Are brain-derived neurotrophic factor (BDNF) and its receptors, NTRK2, NGFR and SORT1, regulated by ovarian steroids in the uterus? SUMMARY ANSWER: BDNF and its low affinity receptor, nerve growth factor receptor (NGFR), are regulated by estradiol in the uterus. WHAT IS KNOWN ALREADY: Recent studies have revealed a central role for neurotrophins in placental development, endometrial stem cell neurogenesis, endometrial carcinoma and endometriosis. Complex signaling pathways involving BDNF and its receptors are regulated by ovarian hormones in the brain, however their expression and regulation in the uterus is poorly defined. STUDY DESIGN, SIZE, DURATION: This experimental animal study involved a total of 80 mice. PARTICIPANTS/MATERIALS, SETTING, METHODS: Female C57BL/6 mice (n = 50) were monitored daily for estrous cycle stage, and uterine horns were collected. A second group of mice (n = 30) were ovariectomized and given estradiol, progesterone, estradiol + progesterone, or saline for 4 days. Uterine expression of BDNF and its receptors were quantified by real-time PCR and western blot, and localized using immunohistochemistry. MAIN RESULTS AND THE ROLE OF CHANCE: During the estrous cycle, expression of BDNF, NTRK2 and SORT1 remained constant, while NGFR declined 11-fold from pro-estrus through to diestrus (P = 0.005). In ovariectomized mice, estradiol treatment increased uterine expression of mature BDNF greater than 6-fold (P = 0.013, 25 kDa; P = 0.003, 27 kDa), pro-BDNF 5-fold (P = 0.041, 37 kDa band; P = 0.046, 40 kDa band), and NGFR 5-fold (P < 0.001) when compared with other treatments. NTRK2 and SORT1 were unaffected by ovarian hormones. NGFR was primarily localized in epithelial cells in mice in diestrus or in ovariectomized mice treated with progesterone (P ≤ 0.001; P ≤ 0.001, respectively). In contrast, NGFR switched to a stromal localization in ovariectomized mice administered estradiol (P = 0.002). LIMITATIONS, REASONS FOR CAUTION: This study was performed in one only species. WIDER IMPLICATIONS OF THE FINDINGS: Results of this study demonstrate the uterine regulation of BDNF and NGFR by estradiol, and highlight the striking difference between hormone exposure during the estrous cycle and daily estradiol exposure after ovariectomy on neurotrophin expression in the uterus. The results also show the spatial regulation of NGFR in the uterus in response to ovarian hormones. Sustained estrogen exposure, as seen in estrogen-dependent disease, may alter the delicate neurotrophin balance and inappropriately activate potent BDNF-NTRK2 pathways which are capable of contributing to endometrial pathology. STUDY FUNDING/COMPETING INTERESTS: This study was supported by the Canadian Institutes of Health Research (CIHR) (W.G.F.), a NSERC Discovery Grant (W.G.F.), and a Vanier Canada Graduate Scholarship-CIHR (J.M.W.). J.M.W. is a member of the CIHR sponsored Reproduction and Early Development in Health training program. The authors declare no conflicts of interest.

Comments on the opinions published by Bergman et al. (2015) on Critical Comments on the WHO-UNEP State of the Science of Endocrine Disrupting Chemicals (Lamb et al., 2014).

Recently Bergman et al. (2015) took issue with our comments (Lamb et al., 2014) on the WHO-UNEP(1) report entitled the "State of the Science of Endocrine Disrupting Chemicals - 2012" (WHO 2013a). We find several key differences between their view and ours regarding the selection of studies and presentation of data related to endocrine disrupting chemicals (EDCs) under the WHO-IPCS(2) definition (2002). In this response we address the factors that we think are most important: 1. the difference between hazard and risk; 2. the different approaches for hazard identification (weight of the evidence [WOE] vs. emphasizing positive findings over null results); and 3. the lack of a justification for conceptual or practical differences between EDCs and other groups of agents.

Reproductive and developmental effects of phthalate diesters in males.

Phthalate diesters are a diverse group of chemicals used to make plastics flexible and are found in personal care products, medical equipment, and medication capsules. Ubiquitous in the environment, human exposure to phthalates is unavoidable; however, the clinical relevance of low concentrations in human tissues remains uncertain. The epidemiological literature was inadequate for prior reviews to conclusively evaluate the effects of phthalates on male reproductive tract development and function, but recent studies have expanded the literature. Therefore, we conducted a systematic review of the literature focused on the effects of phthalate exposure on the developing male reproductive tract, puberty, semen quality, fertility, and reproductive hormones. We conclude that although the epidemiological evidence for an association between phthalate exposure and most adverse outcomes in the reproductive system, at concentrations to which general human populations are exposed, is minimal to weak, the evidence for effects on semen quality is moderate. Results of animal studies reveal that, although DEHP was the most potent, different phthalates have similar effects and can adversely affect development of the male reproductive tract with semen quality being the most sensitive outcome. We also note that developmental exposure in humans was within an order of magnitude of the adverse effects documented in several animal studies. While the mechanisms underlying phthalate toxicity remain unclear, the animal literature suggests that mice are less sensitive than rats and potentially more relevant to estimating effects in humans. Potential for chemical interactions and effects across generations highlights the need for continued study.

Improving the risk assessment of lipophilic persistent environmental chemicals in breast milk.

Lipophilic persistent environmental chemicals (LPECs) have the potential to accumulate within a woman's body lipids over the course of many years prior to pregnancy, to partition into human milk, and to transfer to infants upon breastfeeding. As a result of this accumulation and partitioning, a breastfeeding infant's intake of these LPECs may be much greater than his/her mother's average daily exposure. Because the developmental period sets the stage for lifelong health, it is important to be able to accurately assess chemical exposures in early life. In many cases, current human health risk assessment methods do not account for differences between maternal and infant exposures to LPECs or for lifestage-specific effects of exposure to these chemicals. Because of their persistence and accumulation in body lipids and partitioning into breast milk, LPECs present unique challenges for each component of the human health risk assessment process, including hazard identification, dose-response assessment, and exposure assessment. Specific biological modeling approaches are available to support both dose-response and exposure assessment for lactational exposures to LPECs. Yet, lack of data limits the application of these approaches. The goal of this review is to outline the available approaches and to identify key issues that, if addressed, could improve efforts to apply these approaches to risk assessment of lactational exposure to these chemicals.

Quantitative determination of free and total bisphenol A in human urine using labeled BPA glucuronide and isotope dilution mass spectrometry.

Bisphenol A (BPA) is a widely used industrial chemical in the manufacturing of polycarbonate plastic bottles, food and beverage can linings, thermal receipts, and dental sealants. Animal and human studies suggest that BPA may disrupt normal hormonal function and hence, potentially, have negative effects on the human health. While total BPA is frequently reported, it is recognized that free BPA is the biologically active form and is rarely reported in the literature. The objective of this study was to develop a sensitive and improved method for the measurement of free and total BPA in human urine. Use of a labeled conjugated BPA (bisphenol A-d6 ß-D-glucuronide) allowed for the optimization of the enzymatic reaction and permitted an accurate determination of the conjugated BPA concentration in urine samples. In addition, a (13)C12-BPA internal standard was used to account for the analytical recoveries and performance of the isotope dilution method. Solid-phase extraction (SPE) combined with derivatization and analysis using a triple quadrupole GC-EI/MS/MS system achieved very low method detection limit of 0.027 ng/mL. BPA concentrations were measured in urine samples collected during the second and third trimesters of pregnancy in 36 Canadian women. Total maternal BPA concentrations in urine samples ranged from not detected to 9.40 ng/mL (median, 1.21 ng/mL), and free BPA concentrations ranged from not detected to 0.950 ng/mL (median, 0.185 ng/mL). Eighty-six percent of the women had detectable levels of conjugated BPA, whereas only 22 % had detectable levels of free BPA in their urine. BPA levels measured in this study agreed well with data reported internationally.

Critical comments on the WHO-UNEP State of the Science of Endocrine Disrupting Chemicals - 2012.

Early in 2013, the World Health Organization (WHO) released a 2012 update to the 2002 State of the Science of Endocrine Disrupting Chemicals. Several significant concerns have been identified that raise questions about conclusions reached in this report regarding endocrine disruption. First, the report is not a state-of-the-science review and does not follow the 2002 WHO recommended weight-of-evidence approach. Second, endocrine disruption is often presumed to occur based on exposure or a potential mechanism despite a lack of evidence to show that chemicals are causally established as endocrine disruptors. Additionally, causation is often inferred by the presentation of a series of unrelated facts, which collectively do not demonstrate causation. Third, trends in disease incidence or prevalence are discussed without regard to known causes or risk factors; endocrine disruption is implicated as the reason for such trends in the absence of evidence. Fourth, dose and potency are ignored for most chemicals discussed. Finally, controversial topics (i.e., low dose effects, non-monotonic dose response) are presented in a one-sided manner and these topics are important to understanding endocrine disruption. Overall, the 2012 report does not provide a balanced perspective, nor does it accurately reflect the state of the science on endocrine disruption.

In vitro exposure to cigarette smoke induces oxidative stress in follicular cells of F1 hybrid mice.

This study assessed the influence of cigarette smoke condensate (CSC) and benzo(a)pyrene [B(a)P] on the levels of two oxidative stress biomarkers [8-isoprostane (8-IsoP) and 8-hydroxy-2-deoxy Guanosine (8-OH-dG)], in in-vitro spent media of follicle cells. Follicles (100-130 µm) isolated from ovaries of F1 hybrid (C57Bl/6j × CBA/Ca) mice were cultured for 13 days in media exposed to B(a)P [0 ng ml⁻¹ (control) to 45 ng ml⁻¹] or CSC [0 µg ml⁻¹ (control) to 130 µg ml⁻¹]. The concentrations of oxidative stress biomarkers in spent media were quantified by enzyme-linked immune sorbent assays (ELISA). CSC and B(a)P treatment induced a significant, dose-dependent increase in the concentrations of 8-IsoP and 8-OH-dG in the spent media. We conclude that CSC and B(a)P exposure can induce oxidative stress in ovarian follicles, an effect that may contribute to the previously documented decline in follicle development and premature ovarian failure in women who smoke.