Mono-(2-ethyl-5-hydroxyhexyl) phthalate promotes uterine leiomyoma cell survival through tryptophan-kynurenine-AHR pathway activation.

Uterine leiomyoma is the most common tumor in women and causes severe morbidity in 15 to 30% of reproductive-age women. Epidemiological studies consistently indicate a correlation between leiomyoma development and exposure to endocrine-disrupting chemical phthalates, especially di-(2-ethylhexyl) phthalate (DEHP); however, the underlying mechanisms are unknown. Here, among the most commonly encountered phthalate metabolites, we found the strongest association between the urine levels of mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), the principal DEHP metabolite, and the risk of uterine leiomyoma diagnosis (n = 712 patients). The treatment of primary leiomyoma and smooth muscle cells (n = 29) with various mixtures of phthalate metabolites, at concentrations equivalent to those detected in urine samples, significantly increased cell viability and decreased apoptosis. MEHHP had the strongest effects on both cell viability and apoptosis. MEHHP increased cellular tryptophan and kynurenine levels strikingly and induced the expression of the tryptophan transporters SLC7A5 and SLC7A8, as well as, tryptophan 2,3-dioxygenase (TDO2), the key enzyme catalyzing the conversion of tryptophan to kynurenine that is the endogenous ligand of aryl hydrocarbon receptor (AHR). MEHHP stimulated nuclear localization of AHR and up-regulated the expression of CYP1A1 and CYP1B1, two prototype targets of AHR. siRNA knockdown or pharmacological inhibition of SLC7A5/SLC7A8, TDO2, or AHR abolished MEHHP-mediated effects on leiomyoma cell survival. These findings indicate that MEHHP promotes leiomyoma cell survival by activating the tryptophan-kynurenine-AHR pathway. This study pinpoints MEHHP exposure as a high-risk factor for leiomyoma growth, uncovers a mechanism by which exposure to environmental phthalate impacts leiomyoma pathogenesis, and may lead to the development of novel druggable targets.

Application of wastewater-based epidemiology for estimating population-wide human exposure to phthalate esters, bisphenols, and terephthalic acid.

Phthalates, bisphenols (BPs), and terephthalic acid (TPA) are widely used plasticizers and monomers in plastic manufacturing. Most of them are known to have an adverse effect on the human body, functioning as endocrine disruptors and suspected carcinogens. Access to near real-time data on population exposure to plasticizers is essential for identifying vulnerable communities and better protecting and managing public health locally. The objective of the present study was to evaluate population-level exposure to phthalates, BPs, and TPA by measuring urinary metabolites in community wastewater. Composited community wastewater (24-h samples) from five sewer sub-catchments of a southwestern city within the United States were analyzed for urinary biomarkers of phthalates, BPs, and TPA using solid-phase extraction-liquid chromatography-tandem mass spectrometry in conjunction with the isotope dilution method for absolute quantification. Ten of 16 analytes were detected at least once in community wastewater above the method detection limit (MDL), with MDLs ranging from 37 to 203 ng/L. The population normalized mass load of TPA was the highest, followed by the human metabolite of di-(2-ethylhexyl) phthalate (DEHP). Bisphenol S and monoethyl phthalate were detected with the highest frequency. Study findings suggest that analyzing municipal wastewater for chemical indicators of human exposure to plastic constituents is feasible, practicable, and informative, as long as appropriate steps are taken to determine, quantify and account for background levels of plastic analytes in the laboratory environment.

Urinary concentration of endocrine-disrupting phthalates and breast cancer risk in Indian women: A case-control study with a focus on mutations in phthalate-responsive genes.

BACKGROUND: Phthalates are known endocrine-disrupting chemicals used indiscriminately as constituents in consumer products including food processing, and packaging, cosmetics, personal care and household items. Although, few studies have assessed the risk of breast cancer on exposure to phthalates, their association with breast cancer risk in Indian women have not yet been evaluated. METHODS: We conducted a case-control study involving 171 participants. Urinary concentrations of six phthalate dieters; DMP (Dimethyl phthalate), DEP (Diethyl phthalate), DBP (Dibutyl phthalate), BBP (benzyl butyl phthalate), DEHP (Di-2-ethyl-hexyl phthalate), DINOP (Di-n-octyl phthalate) were estimated by GC-MS and geometric means were calculated. Univariate and multivariable logistic regression was performed to assess breast cancer risk on exposure to phthalates. Genes responsive to phthalates were identified through literature search and matched with NGS data, and gene-enrichment analysis was performed. RESULTS: Significant associations were observed between urinary phthalate concentrations and increased risk of breast cancer for di-butyl phthalate (OR=1.5, 95% CI; 1.06, 2.11, p = 0.002) and di-2-ethyl-hexyl phthalate (>median vs ≤ median; OR=2.97, 95% CI; 1.18, 7.47, p = 0.005) in multivariable analyses. We also found several phthalate-responsive gene mutations in paired breast tumor tissues, which include PTPRD (76.19%), AR (42.86%), CYP1A1 (42.86%), CYP19A1 (23.81%), AHRR (19.05%), PIK3CA (19.05%), CYP1B1 (9.52%), RB1 (9.52%) and MMP9 (9.52%). Gene-enrichment analysis revealed that these genes form a major part of ER/PR, PPAR and HIF-1α-TGF-ß signaling cascades involved in breast cancer CONCLUSION: Although the sample size is small, in this first case-control study from India, DBP and DEHP were found to be associated with increased risk of invasive breast cancer and tumor tissues revealed mutations in several phthalate-responsive genes. It is, therefore suggested that human biomonitoring in India and larger studies evaluating the early life genetic and epigenetic alterations on phthalates exposure are required to establish their role in breast carcinogenesis.

Levels and health risks of urinary phthalate metabolites and the association between phthalate exposure and unexplained recurrent spontaneous abortion: a large case-control study from China.

Phthalate acid esters (PAEs) are environmental endocrine disruptors that can interfere with endocrine processes and cause adverse reproductive outcomes. The link between PAE exposure and unexplained recurrent spontaneous abortion (URSA) remains unknown. In this study, nine urinary metabolites of PAEs (mPAEs) were measured in 594 URSA cases and 569 healthy controls. The measured mPAEs were ubiquitously detected and present at higher levels (median: 203 ng/mL) in the URSA cases than in the controls (median: 161 ng/mL). Multiple logistic regression analysis showed that URSA was associated with higher concentrations of mono (2-ethyl-5-hydroxyhexyl) phthalate (mEHHP), mono (2-ethylhexyl) phthalate (mEHP), and mono-ethyl phthalate (mEP) and lower concentrations of mono-isobutyl phthalate (miBP). Moreover, a quantile-based g-computation (QGC) model revealed a positive association between mPAEs mixture and URSA. The URSA cases showed significantly higher concentrations of di-(2-ethylhexyl) phthalate (DEHP) than the controls. This was consistent with the health risk assessment, which suggested that DEHP is the main contributors to potential non-carcinogenic risk. DEHP accounted for over 80% of total risk. The large case-control study results suggest that PAE exposure may increase the risk of URSA, and that policy-makers and public health experts should pay more attention to DEHP exposure.

Exposure to Di-2-ethylhexyl Phthalate and Benign Prostatic Hyperplasia, NHANES 2001-2008.

30% of men suffer from benign prostatic hyperplasia (BPH) worldwide. As one of the most important members of Phthalate esters, previous studies suggested ubiquitous Di-(2-ethylhexyl) phthalate (DEHP) exposure is associated with such male disorders by interfering with endocrine system, however, little is known about the association between DEHP exposure and BPH. The objective of this study was to study the potential association by the 2001-2008 National Health and Nutrition Examination Survey (NHANES) data. The data was collected, and multiple logistic regression was adapted to measure the association. The concentrations of DEHP (∑DEHP) were calculated by each metabolite and split into quartiles for analysis. Results showed that the odds ratio (OR) decreased with increased ∑DEHP concentration. In the crude model, the OR for the second quartile (OR = 1.60, 95%CI [1.24, 2.07]) was obviously higher compared with the lowest quartile. However, the OR for the highest quartile (OR = 0.55, 95%CI [0.44,0.69]) was lower than that for the third quartile (OR = 0.77, 95%CI [0.61, 0.97]), and the OR for the third and the highest quartile were significantly lower than that of the lowest quartile, which suggested biphasic effects of DEHP based on concentration. The results showed the same trend after adjusting confounding factors. The study suggested that the DEHP exposure is associated with DEHP, and the results adds limited evidence to study this topic, however, further researches are needed to determine if the status of BPH can be changed by controlling DEHP exposure.

Associations of urinary phthalate metabolites with risk of papillary thyroid cancer.

Some studies have revealed thyrotoxicity of phthalates; however, associations of phthalate exposure with papillary thyroid cancer (PTC) remain unclear. We conducted a pair-matching case-control study of 111 PTC cases and 111 age- and sex-matched non-PTC controls to examine associations between urinary concentrations of phthalate metabolites and PTC. Phthalate metabolites were determined in fasting urine specimens by ultra-performance liquid chromatography - tandem mass spectrometry (UPLC-MS/MS). After adjusting for potential confounders and other phthalate metabolites, the concentrations of the sum of di (2-ethylhexly) phthalate (DEHP) metabolites in urine were positively associated with PTC [odds ratio (OR) = 5.35; 95% confidence interval (CI): 1.61-17.83], suggesting the effect of phthalates exposure on PTC development. The findings require confirmation.

Perioperative Exposure to Suspect Neurotoxicants From Medical Devices in Newborns With Congenital Heart Defects.

BACKGROUND: Industrial chemicals are increasingly recognized as potential developmental neurotoxicants. Di(2-ethylhexyl) phthalate (DEHP), used to impart flexibility and temperature tolerance to polyvinylchloride, and bisphenol A (BPA), used to manufacture polycarbonate, are commonly present in medical devices. The magnitude of exposure in neonates during hospitalization for cardiac operations is unknown. METHODS: We quantified urinary concentrations of DEHP metabolites and BPA preoperatively and postoperatively in neonates undergoing cardiac operations and their mothers. Urinary concentrations of these biomarkers reflect recent exposures (half-lives are approximately 6 to 24 hours). Biomarker concentrations in mothers' and infants' preoperative and postoperative samples were compared. RESULTS: Operations were performed in 18 infants (mean age, 5 ± 4 [SD] days). The maternal sample was obtained on postpartum day 4 ± 4. The preoperative urine sample was obtained on day-of-life 4 ± 2 and the postoperative sample on day-of-life 6 ± 4. Mean maternal concentrations for DEHP metabolites and BPA were at the 50th percentile for females in the United States general population. Infant preoperative concentrations of 1 DEHP metabolite and BPA were significantly higher than maternal concentrations. Postoperative concentrations for all DEHP metabolites were significantly greater than preoperative concentrations. CONCLUSIONS: There is considerable perioperative exposure to DEHP and BPA for neonates undergoing cardiac operations. Infant concentrations for both BPA and DEHP metabolites were significantly higher than maternal concentrations, consistent with the infant's exposure to medical devices. Further study is needed to determine the potential role of these suspect neurotoxicants in the etiology of neurodevelopmental disability after cardiac operations.

In vitro effects of phthalate esters in human myometrial and leiomyoma cells and increased urinary level of phthalate metabolite in women with uterine leiomyoma.

OBJECTIVE: To investigate the possible role of phthalate, a ubiquitous chemical used in consumer products, in the pathogenesis of uterine leiomyoma. DESIGN: Experimental and prospective case-control study using human samples. SETTING: University hospital. PATIENT(S): Fifty-three women with histologic evidence of uterine leiomyoma and 33 surgical controls without leiomyoma. INTERVENTION(S): Human myometrial and leiomyoma cells were treated with di-(2-thylhexyl)-phthalate (DEHP). MAIN OUTCOME MEASURE(S): Cell viability assay and Western blot analyses after in vitro DEHP treatment; high-performance liquid chromatography electrospray ionization tandem mass spectrometry in cases and controls. RESULT(S): In vitro treatment with DEHP led to an increased viability and increased expressions of proliferating cell nuclear antigen, B-cell lymphoma 2 protein, and type I collagen in myometrial and leiomyoma cells. The urinary concentration of mono-(2-ethyl-5-carboxypentyl) phthalate was higher in women with leiomyoma compared with controls. CONCLUSION(S): These findings suggest that exposure to phthalate may play a role in the pathogenesis of uterine leiomyoma by enhancing proliferative activity, exerting an antiapoptotic effect, and increasing collagen contents in myometrial and leiomyoma cells.

Increased Urinary Phthalate Levels in Women with Uterine Leiomyoma: A Case-Control Study.

We assessed the urinary concentration of 16 phthalate metabolites in 57 women with and without uterine leiomyoma (n = 30 and 27; respectively) to determine the association between phthalate exposure and uterine leiomyoma. To evaluate exposure to di-(2-ethylhexyl) phthalate (DEHP); we calculated the molar sum of DEHP metabolites; ∑3-DEHP (combining mono-(2-ethylhexyl) phthalate (MEHP); mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP); and mono-(2-ethyl-5-oxohexyl) phthalate); ∑4-DEHP (∑3-DEHP plus mono-(2-ethyl-5-carboxypentyl) phthalate); and ∑5-DEHP (∑4-DEHP plus mono (2-(carboxylmethyl)hexyl) phthalate (2cx-MMHP)). The log transformed urinary levels of MEHP; MEHHP; 2cx-MMHP; ∑3-DEHP; ∑4-DEHP; and ∑5-DEHP in the leiomyoma group were significantly higher than those of controls. When we adjusted for age; waist circumference; and parity using multiple logistic regression analyses; we found log ∑3-DEHP (OR = 10.82; 95% CI = 1.25; 93.46) and ∑4-DEHP (OR = 8.78; 95% CI = 1.03; 75.29) were significantly associated with uterine leiomyoma. Our findings suggest an association between phthalate exposure and uterine leiomyoma. However; larger studies are needed to investigate potential interactions between phthalate exposure and uterine leiomyoma.

Urinary Concentrations of Phthalate Metabolites and Pregnancy Loss Among Women Conceiving with Medically Assisted Reproduction.

BACKGROUND: Animal studies demonstrate that several phthalates are embryofetotoxic and are associated with increased pregnancy loss and malformations. Results from human studies on phthalates and pregnancy loss are inconsistent. METHODS: We examined pregnancy loss prospectively in relation to urinary phthalate metabolite concentrations among women undergoing medically assisted reproduction. We used data from 256 women conceiving 303 pregnancies recruited between 2004 and 2012 from the Massachusetts General Hospital Fertility Center. We quantified 11 phthalate metabolite concentrations and calculated the molar sum of four di(2-ethylhexyl) phthalate (DEHP) metabolites (ΣDEHP). We estimated risk ratios (RRs) and 95% confidence intervals for biochemical loss and total pregnancy loss (<20 weeks' gestation) across quartiles using repeated measures log-binomial models, adjusted for age, body mass index, smoking and infertility diagnosis. RESULTS: Of the 303 pregnancies, 83 (27%) ended in loss less than 20 weeks' gestation and among these, 31 (10%) ended in biochemical loss. Although imprecise, the RRs for biochemical loss increased across quartiles of ΣDEHP and three individual DEHP metabolites. For ΣDEHP, the RRs (confidence intervals) were 2.3 (0.63, 8.5), 2.0 (0.58, 7.2), and 3.4 (0.97, 11.7) for quartiles two, three, and four, compared with one, respectively (P trend = 0.04). RRs for total pregnancy loss were elevated in the highest quartiles of ΣDEHP and three DEHP metabolites. The remaining seven phthalate metabolite concentrations evaluated were not associated with either outcome. CONCLUSIONS: We found a suggestive pattern of association between conception cycle-specific urinary concentrations of DEHP metabolites and biochemical and total pregnancy loss among women undergoing medically assisted reproduction.

Associations of individual characteristics and lifestyle factors with metabolism of di-2-ethylhexyl phthalate in NHANES 2001-2012.

BACKGROUND: Previous studies suggest that a higher ratio of primary to secondary metabolites of di-2-ethylhexyl phthalate (DEHP), reflective of a slower DEHP conversion rate, is associated with a greater physiologic effect. We examined associations of several individual characteristics and lifestyle factors with the ratio of mono-2-ethylhexyl phthalate to mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHP:MEHHP) and %MEHP (the ratio of MEHP to the sum of the secondary metabolites). METHODS: We used the data from the National Health and Nutrition Examination Survey, 2001-2012. The study included adults with BMI<30 and no diabetes. Pregnant women were excluded. We examined associations of age, race, gender, Body Mass Index, smoking, alcohol and caffeine consumption, medication use, cancer history, and menopausal status and postmenopausal hormone use (in women) with MEHP:MEHHP and %MEHP using multivariable linear regression. The values for %MEHP were log-transformed in the analysis. RESULTS: In multivariable analysis, non-Caucasian individuals had higher %MEHP (non-Hispanic Blacks: ß=0.114, 95% Confidence interval [CI]: 0.050, 0.177; Hispanic: ß=0.089, 95% CI: 0.024, 0.154; other race: ß=0.126, 95% CI: 0.033, 0.219). Age was inversely associated with MEHP:MEHHP (ß=-0.001, 95% CI: -0.002, -0.001) and %MEHP (ß=-0.006, 95% CI: -0.008, -0.004). Overweight individuals had lower MEHP: MEHHP and lower %MEHP (ß=-0.035, 95% CI: 0.062, -0.008 and ß=-0.104, 95% CI: -0.162, -0.046, respectively). Alcohol consumption was inversely associated with %MEHP among men (p-trend=0.03). CONCLUSIONS: Individual and lifestyle characteristics are associated with differences in DEHP metabolism. Understanding underlying biological mechanisms could help to identify individuals at a greater risk of adverse effects from DEHP exposure.

Prenatal Stress as a Modifier of Associations between Phthalate Exposure and Reproductive Development: results from a Multicentre Pregnancy Cohort Study.

BACKGROUND: Prenatal phthalate exposure is associated with altered male reproductive tract development, and in particular, shorter anogenital distance (AGD). AGD, a sexually dimorphic index of prenatal androgen exposure, may also be altered by prenatal stress. How these exposures interact to impact AGD is unknown. Here, we examine the extent to which associations between prenatal phthalate exposure and infant AGD are modified by prenatal exposure to stressful life events (SLEs). METHODS: Phthalate metabolites [including those of diethylhexyl phthalate (DEHP) and their molar sum (ΣDEHP)] were measured in first trimester urine from 738 pregnant women participating in The Infant Development and the Environment Study (TIDES). Women completed questionnaires on SLEs, and permitted infant AGD measurements at birth. Subjects were classified as 'lower' and 'higher' stress (0 first trimester SLEs vs. 1+).We estimated relationships between phthalate concentrations and AGD (by infant sex and stress group) using adjusted multiple regression interaction models. RESULTS: In the lower stress group, first trimester ΣDEHP was inversely associated with two measures of male AGD: anoscrotal distance (AGD-AS; ß = -1.78; 95% CI -2.97, -0.59) and anopenile distance (AGD-AP; ß = -1.61; 95% CI -3.01, -0.22). By contrast, associations in the higher stress group were mostly positive and non-significant in male infants. No associations were observed in girls. CONCLUSIONS: Associations between prenatal phthalate exposure and altered genital development were only apparent in sons of mothers who reported no SLEs during pregnancy. Prenatal stress and phthalates may interact to shape fetal development in ways that have not been previously explored.

Urinary phthalate metabolite concentrations in relation to history of infertility and use of assisted reproductive technology.

OBJECTIVE: To examine urinary phthalate metabolite concentrations in pregnant women with planned pregnancies in relation to history of infertility and use of assisted reproductive technology (ART). DESIGN: Phthalate metabolite concentrations were measured in first-trimester urine samples collected from women participating in a prospective pregnancy cohort study. SETTING: Prenatal clinics. PATIENT(S): A total of 750 women, of whom 86 had a history of infertility. Forty-one women used ART to conceive. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Primary outcomes were concentrations of four metabolites of diethylhexyl phthalate (DEHP) and their molar sum (∑DEHP). Multivariable analyses compared phthalate metabolite levels in [1] women reporting a history of infertility vs. those who did not (comparison group); and [2] those who used ART to conceive the index pregnancy vs. women with a history of infertility who did not use ART. RESULT(S): Among women with a history of infertility, ∑DEHP was significantly lower in women who conceived after ART compared with those who did not (geometric mean ratio: 0.83; 95% confidence interval 0.71-0.98). Similar significant associations were observed for all of the individual DEHP metabolites. There were no differences in DEHP metabolite concentrations between women with a history of infertility and the comparison group. CONCLUSION(S): Women who used ART to conceive had lower first-trimester phthalate metabolite concentrations than women with a history of infertility who did not use ART. Further research is needed to explore whether those pursuing fertility treatments take precautions to avoid exposure to environmental toxins, to improve treatment outcomes.

Carryover Effects of Acute DEHP Exposure on Ovarian Function and Oocyte Developmental Competence in Lactating Cows.

We examined acute exposure of Holstein cows to di(2-ethylhexyl) phthalate (DEHP) and its carryover effects on ovarian function and oocyte developmental competence. Synchronized cows were tube-fed with water or 100 mg/kg DEHP per day for 3 days. Blood, urine and milk samples were collected before, during and after DEHP exposure to examine its clearance pattern. Ovarian follicular dynamics was monitored through an entire estrous cycle by ultrasonographic scanning. Follicular fluids were aspirated from the preovulatory follicles on days 0 and 29 of the experiment and analyzed for phthalate metabolites and estradiol concentration. The aspirated follicular fluid was used as maturation medium for in-vitro embryo production. Findings revealed that DEHP impairs the pattern of follicular development, with a prominent effect on dominant follicles. The diameter and growth rate of the first- and second-wave dominant follicles were lower (P < 0.05) in the DEHP-treated group. Estradiol concentration in the follicular fluid was lower in the DEHP-treated group than in controls, and associated with a higher number of follicular pathologies (follicle diameter >25 mm). The pattern of growth and regression of the corpus luteum differed between groups, with a lower volume in the DEHP-treated group (P < 0.05). The follicular fluid aspirated from the DEHP-treated group, but not the controls, contained 23 nM mono(2-ethylhexyl) phthalate. Culturing of cumulus oocyte complexes in the follicular fluid aspirated from DEHP-treated cows reduced the proportion of oocytes progressing to the MII stage, and the proportions of 2- to 4-cell-stage embryos (P < 0.04) and 7-day blastocysts (P < 0.06). The results describe the risk associated with acute exposure to DEHP and its deleterious carryover effects on ovarian function, nuclear maturation and oocyte developmental competence.

Relationship between urinary concentrations of di(2-ethylhexyl) phthalate (DEHP) metabolites and reproductive hormones in polyvinyl chloride production workers.

OBJECTIVES: We investigated the relationship between urinary metabolites of di(2-ethylhexyl) phthalate (DEHP) and reproductive hormones in workers of polyvinyl chloride (PVC) production plants. After exposure, most of the DEHP is rapidly metabolised to mono(2-ethylhexyl) phthalate (MEHP), mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) and mono(2-ethyl-5-oxohexyl) phthalate (MEOHP), which may be associated with reproductive hormone interruption and testicular toxicity. Some studies report that urinary concentrations of phthalate metabolites for plastics workers are significantly higher than for the general population. However, little is known about the disruption of reproductive hormones for DEHP exposure workers. METHODS: This cross-sectional study of 82 male workers measured the biomarkers for their reproductive hormones and their exposure to DEHP. Relationships between urinary concentrations of DEHP metabolites were estimated using multivariate linear regression and quartile analysis models. RESULTS: The geometric means of urinary creatinine-adjusted (µg/g-Cre) concentrations of MEHP, MEOHP and MEHHP during the post-shift period were 23.9, 66.9 and 84.6, respectively. In multiple regression models adjusted for potential confounders, there were significant positive associations between urinary concentrations of DEHP metabolites and estradiol (E2) (p<0.01), and in the ratio of E2 to testosterone (p<0.05). Moreover, quartile analysis showed significant positive relationships between the total urinary concentration of DEHP metabolites and E2 (ptrend=0.024), and in the ratio of E2 to testosterone (ptrend=0.031). CONCLUSIONS: Relationships between reproductive hormones and the total urinary concentration of DEHP metabolites in male PVC production workers were significantly positive. This indicated that aromatase activity had increased in male workers exposed to DEHP, which is consistent with animal studies.

[Study on the association between maternal urinary phthalate metabolites and testicular steroid hormones in the cord blood in a Chinese population].

OBJECTIVE: The purposes of our study were to investigate the association between maternal urinary phthalate metabolites and the levels of inhibin B (INHB) and insulin-like factor 3 (INSL3) in the cord blood in a Chinese pregnant population. METHODS: Maternal urine samples in the third trimester of pregnancy of 69 participants were collected and stored, and the samples of cord blood (10 ml) were collected at delivery between June 2011 and September 2012 in a comprehensive hospital of gynecology and obstetrics in Tianjin, China.Four phthalate metabolites, monomethyl phthalate (MMP), monoethyl phthalate (MEP), monobutyl phthalate (MBP), and mono-2-ethylhexyl phthalate (MEHP) were measured in the urine samples using liquid chromatography-tandem mass spectrometry. The levels of INHB, INSL3 in the cord blood were tested by ELISA. Associations of phthalate exposure with INHB and INSL3 levels were determined by spearman correlation and multiple regression model analysis. RESULTS: The median concentrations of observed metabolites in descending order were 49.74 µg/L for MMP, 24.96 µg/L for MEHP, 19.52 µg/L for MEP and 17.73 µg/L for MBP. The median concentrations of INHB and INSL3 were 89.09 and 106.21 ng/L.Significant negative associations between INHB and MMP(ß' = -0.252), MEP(ß' = -0.363) or the sum value (∑PAEs) (ß' = -0.346) were found by the multiple regression model analysis. For INSL3, only the sum value (ß' = -0.313) was inversely significantly associated with the levels of INSL3 in the cord blood. CONCLUSIONS: Maternal urinary phthalate metabolites were associated with INHB and INSL3 in the cord blood in a Chinese population.

Urinary metabolites of di(2-ethylhexyl) phthalate relation to sperm motility, reactive oxygen species generation, and apoptosis in polyvinyl chloride workers.

PURPOSE: To measure the concentrations of urinary di(2-ethylhexyl) phthalate (DEHP) metabolites in polyvinyl chloride (PVC) workers and a control group for determining the relationship of DEHP exposure to semen quality, sperm reactive oxygen species (ROS) generation, and sperm apoptosis. METHODS: We assessed the metabolites of DEHP, namely urinary mono-(2-ethylhexyl) phthalate (MEHP), mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), and mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP), and semen quality, such as sperm concentration, motility, morphology, ROS generation, and DNA damage by using terminal deoxynucleotidyl transferase-mediated nick end labeling assay obtained from 47 workers employed within two PVC pellet plants and 15 graduate students in Taiwan. RESULTS: Sperm concentration and motility were significantly affected in the high-exposure group. The percentage and intensity of sperm ROS generation were higher in the high-exposure group than those in the control group. After adjustment for age, smoking status, and coffee consumption, the decrease in sperm motility was inversely associated with the concentration of MEHP (ß = -0.549, p = 0.0085), MEHHP (ß = -0.155, p = 0.0074), and MEOHP (ß = -0.201, p = 0.0041). Moreover, sperm apoptosis and ROS generation were positively associated with MEHHP and MEOHP concentration, respectively. CONCLUSIONS: This was the first study to explore the associations between levels of DEHP exposure, sperm motility, ROS generation, and apoptosis. The results suggested that urinary MEHHP and MEOHP were sensitive biomarkers for reflecting the relationship between DEHP exposure and semen quality.

The association between some endocrine disruptors and hypospadias in biological samples.

Hypospadias is a birth defect found in boys in which the urinary tract opening is not at the tip of the penis. The etiology of hypospadias is still unidentified, but endocrine disruptors are considered as one possible cause of hypospadias. In this study, target endocrine disruptor compounds were established for an assay. The target compounds included 5 phthalates (di-(2-ethylhexyl)phthalate (DEHP), di-n-butyl-phthalate (DBP), mono-(2- ethylhexyl) phthalate (MEHP), mono-n-butyl-phthalate (MBP) and phthalic acid (PA)), 2 alkylphenols (n-nonylphenol (n-NP) and t-octylphenol (t-OP)) and bisphenol A. The association between these 8 endocrine disruptors and hypospadias was studied. The levels of endocrine disruptors in the urine and plasma of a control group were compared with those of a patient group. DEHP (P = 0.006) and n-NP (P = 7.26e-6) in the urine samples and PA (P = 0.009) and BPA (P = 7.22e-10) in the plasma samples showed a significant association with hypospadias. The levels of endocrine disruptors in the urine and plasma of the mothers were also compared to those of the patients to investigate the metastasis of the endocrine disruptors from the mother. These levels did not, however, show a relationship with hypospadias (R(2) = 0.001-0.563).

Urinary phthalate excretion in 555 healthy Danish boys with and without pubertal gynaecomastia.

Pubertal gynaecomastia is a clinical sign of an oestrogen-androgen imbalance, which occurs in 40-60% of adolescent Caucasian boys. In most cases no underlying endocrinopathy can be identified. A recent study reports higher plasma phthalate levels in Turkish boys with pubertal gynaecomastia. Therefore, we asked whether there was an association between concurrent measures of urinary phthalate metabolites and pubertal timing as well as the presence of gynaecomastia in otherwise healthy boys. We studied a total of 555 healthy boys (age 6.07-19.83 years) as part of the COPENHAGEN Puberty Study. Anthropometry and pubertal stages (PH1-6 and G1-5) were evaluated, and the presence of gynaecomastia was assessed. Non-fasting blood samples were analysed for serum testosterone and morning urine samples were analysed for the total content of 12 phthalate metabolites (MEP, MnBP, MiBP, MBzP, MEHP, MEHHP, MEOHP, MECPP, MiNP, MHiNP, MiONP and MCiOP) by LC-MS/MS. A statistically significant negative correlation was observed between chronological age and the urinary concentration of the sum of measured metabolites DEHP (∑DEHPm) (r = -0.164) and DiNP (∑DiNPm) (r = -0.224), respectively, and the sum of monobutyl phthalate (MBP) isomers (∑MBP((i+n))) (r = -0.139) (all with p < 0.01). In contrast urinary monoethyl phthalate concentration was positively correlated to age (r = 0.187, p < 0.01). The urinary levels of phthalate metabolites were not associated with age at pubertal onset, serum testosterone levels or presence of gynaecomastia. In conclusion, we did not find evidence of anti-androgenic effects of phthalates in our healthy boys. Thus, current phthalate exposure was not associated with pubertal timing, testosterone levels or with the presence of pubertal gynaecomastia in this cross-sectional study. However, longitudinal studies are needed to evaluate possible perinatal or long-term postnatal effects of phthalates on healthy boys.

Personal care product use and urinary levels of phthalate metabolites in Mexican women.

Sources of phthalates other than Polyvinyl chloride (PVC) related products are scarcely documented in Mexico. The objective of our study was to explore the association between urinary levels of nine phthalate metabolites and the use of personal care products. Subjects included 108 women who participated as controls in an ongoing population-based case-control study of environmental factors and genetic susceptibility to breast cancer in northern Mexico. Direct interviews were performed to inquire about sociodemographic characteristics, reproductive history, use of personal care products, and diet. Phthalate metabolites measured in urine by high performance liquid chromatography-isotope dilution tandem mass spectrometry were monoethyl phthalate (MEP), monobenzyl phthalate (MBzP), mono-n-butyl phthalate (MBP), mono-isobutyl phthalate (MiBP), mono-3-carboxypropyl phthalate (MCPP) as well as mono-2-ethylhexyl phthalate (MEHP), mono-2-ethyl-5-oxohexyl phthalate (MEOHP), mono-2-ethyl-5-hydroxyhexyl phthalate (MEHHP), mono-2-ethyl-5-carboxypentyl phthalate (MECPP) that are metabolites of di-ethylhexyl phthalate (DEHP). Detectable urinary concentrations of phthalate metabolites varied from 75% (MEHP) to 100% (MEP, MBP, MEOHP, MEHHP and MECPP). Medians of urinary concentrations of some phthalate metabolites were significantly higher among users of the following personal care products compared to nonusers: body lotion (MEHHP, MECPP and sum of DEHP metabolites (ΣDEHP)), deodorant (MEHP and ΣDEHP), perfume (MiBP), anti-aging facial cream (MEP, MBP and MCPP) and bottled water (MCPP, MEHHP and MEOHP). Urinary concentrations of MEP showed a positive relationship with the number of personal care products used. Our results suggest that the use of some personal care products contributes to phthalate body burden that deserves attention due to its potential health impact.