Plasma phthalate levels in pubertal gynecomastia

Association between BMI and age at menarche or spermarche among both sexes: Findings from six successive national surveys in China

Background

To explore trends of the association between body mass index (BMI) and age at menarche or spermarche and its urban-rural disparities from 1995 to 2019.

Methods

A total of 912 753 children and adolescents - including 519 940 9-18 years old girls and 392 813 11-18 years old boys - were involved in six successive cross-sectional surveys conducted across 30 provinces in China from 1995 to 2019. Data on menarche and spermarche was collected using the status quo method, where same-gender physicians conducted face-to-face interviews to determine if children and adolescents had experienced their first menstrual cycle or ejaculation (yes/no). The median age at menarche or spermarche was estimated by probit analysis. Anthropometric measurements measured the height and weight of the study subjects. Children and adolescents were classified into thinness, normal range of weight, overweight, and obesity. t test was used to compare the differences in BMI between premenarchal and postmenarchal girls or prespermarcheal and postspermarcheal boys. Logistic regression was used to explore the associations between BMI/nutritional status and menarche or spermarche stratified by urban or rural residency status.

Results

From 1995 to 2019, BMI in all age groups growth over time, and the values of BMI among children and adolescents under 15 who had menarche or spermarche were more significant than those without menarche or spermarche. In 2019, for girls, thinness was associated with delayed menarche (odds ratio (OR) = 0.26; 95% confidence interval (CI) = 0.24-0.28), while overweight (OR = 1.99; 95% CI = 1.85-2.14) and obesity (OR = 2.20; 95% CI = 1.92-2.53) was associated with advanced menarche. For boys, thinness was associated with delayed spermarche (OR = 0.71; 95% CI = 0.65-0.78), overweight was associated with advanced spermarche (OR = 1.08; 95% CI = 1.01-1.15) while obesity had no association with spermarche. The OR between BMI and menarche in 1995 was 1.35 (95% CI = 1.33-1.37), which decreased to 1.19 (95% CI = 1.18-1.20) by 2019. The OR between BMI and spermarche in 1995 was 1.10 (95% CI = 1.09-1.11), which decreased to 1.02 (95% CI = 1.02-1.03) by 2019. The trends by urban-rural stratification were consistent with the total sample.

Conclusions

We have established a dose-response relationship between BMI and menarche in girls, whereas the association appears to be nonlinear in boys, and the associations were diminishing. Similar findings were observed in both urban and rural areas. Considering the dual adverse effects of obesity and early puberty on health, the results of this study suggest that sexual health education should be strengthened, especially among obese girls. Further research on the influencing factors and biological mechanisms of early puberty will be beneficial.

Leaching of di-2-ethylhexyl phthalate from biodegradable and conventional microplastics and the potential risks

There has been a growing concern about plastic pollution, both from a health and ecological perspective. One of the major concerns with plastic debris, especially microplastics (MPs) relates to their strong potential for releasing additives and chemicals. Di-2-ethylhexyl phthalate (DEHP) is a common plastic additive widely used as plasticizer in plastic products, and is of global concern due to its widespread contamination in the environment. In this study, two conventional nondegradable plastics (polyethylene (PE) bags and PE mulch) and two biodegradable plastics (poly(butylene adipate co-terephtalate)-starch-based-polylactic acid bags (PBAT/PLA bags) and PLA mulch) were selected to investigate the release of DEHP to seawater. The results showed that leaching potentials of DEHP from different types of MPs varied. Among the four selected MPs, PE mulch had the highest leaching potential (6.88 μg/g), followed by PE bags (4.24 μg/g), PLA mulch (1.10 μg/g) and PBAT/PLA bags (0.89 μg/g). The DEHP leaching kinetic curves of the four MPs were all in line with the pseudo first order model. The potential risk of environmental and human exposure to the leached DEHP was assessed using the average Phthalate Pollution Index (PPI). The calculated PPI indicated low pollution risks of DEHP released by the four MPs in seawater.

Longitudinal evaluation of breast tissue in healthy infants: Prevalence and relation to reproductive hormones and growth factors

INTRODUCTION

Breast tissue in infancy is a rather undescribed phenomenon. We aimed to describe the prevalence and progression of palpable breast tissue in healthy boys and girls aged 0-1 years and to evaluate clinical markers, individual serum hormone concentrations as well as combined hormone profiles as determinants of the persistence of breast tissue.

METHODS

In total, 233 term infants (119 boys, 114 girls) were included and followed from birth until 1 year of age in The COPENHAGEN Minipuberty Study (ClinicalTrials.gov #NTC02784184). Infants were followed up to six times with a clinical examination and serum sampling. Principal component analyses (PCAs) produced combined hormone profiles.

RESULTS

A total of 98% of all infants aged 0-1 year exhibited breast tissue at some point. 50% still had breast tissue present at 0.5-0.6 years in girls and 0.3-0.4 years in boys ('persistent'). At one year, more girls than boys had breast tissue present (p=0.010). Most clinical and hormonal markers did not differ in infants with/without persistent breast tissue. However, in those with persistent breast tissue, estradiol (first visit, girls, p=0.034), androstenedione, corticosterone, cortisol (first visit, boys, all p<0.050), length (first visit, boys, p=0.030), and testicular volume (0.3-0.4 years, p=0.040) were higher, while IGF-I (0.3-0.4, boys, p=0.033) was lower. In boys, a combined, PCA-derived hormone profile (first visit) was able to predict the persistence of breast tissue (area under the curve=83%) better than any single marker.

DISCUSSION

Palpable breast tissue in infancy is common in both sexes although it persists in significantly more girls than boys at one year of age. Data supports both the early origin of breast tissue (in utero- and early postnatal) as well as a role of endogenous hormone production in later development and maintenance.

Low-dose mono(2-ethylhexyl) phthalate promotes ovarian cancer development through PPARα-dependent PI3K/Akt/NF-κB pathway

The plasticizer di(2-ethylhexyl) phthalate (DEHP) and its hydrolysate mono(2-ethylhexyl) phthalate (MEHP) are major toxicants from plastics, but their association with hormone-dependent cancers has been controversial. We treated the human ovarian cancer cell lines SKOV3 and A2780 with low concentrations of DEHP/MEHP, and found that although no significant effect on cell proliferation was observed, ovarian cancer cell migration, invasion, and epithelial-mesenchymal transition (EMT) were promoted by submicromolar MEHP but not DEHP. Next, ovarian cancer patient data from The Cancer Genome Atlas (TCGA) were obtained and subjected to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) supported enrichment and Kaplan-Meier survival analyses, which identified PI3K/Akt pathway as a pivotal signaling pathway in ovarian cancer. We found that 500 nM MEHP treatment significantly increased PIK3CA expression, which could be reversed by the knockdown of peroxisome proliferator-activated receptor alpha (PPARα). Silencing PIK3CA significantly suppressed the MEHP-induced migration, invasion and EMT. In addition, we validated that MEHP treatment promoted phosphorylation of Akt and degradation of IκB-α, thereby activating NF-κB and enhancing NF-κB nuclear translocation. In nude mice, MEHP exposure significantly promoted the metastasis of ovarian cancer xenografts, which could be suppressed by the treatment of PPARα inhibitor GW6471. Our findings showed that low-dose MEHP promoted ovarian cancer progression through activating PI3K/Akt/NF-κB pathway, in a PPARα-dependent manner.

Research progress on the effect of Di-(2-ethylhexyl) phthalate (DEHP) on reproductive health at different periods in life

Di-(2-ethylhexyl) phthalate (DEHP) is a representative endocrine-disrupting chemical (EDC) that has reproductive, developmental, neurological and immune toxicity in humans and rodents, of which damage to the reproductive system is the most serious. However, exposure to DEHP at different stages of life may produce different symptoms. Studies on this substance are also controversial. This review describes the reproductive effects of DEHP in males and females at different life stages, including infancy, childhood and adulthood.

Effects of endocrine disruptors on fetal testis development, male puberty, and transition age

PURPOSE

Endocrine disruptors (EDs) are exogenous substances able to impair endocrine system; consequently, they may cause numerous adverse effects. Over the last years, particular focus has been given to their harmful effects on reproductive system, but very little is known, especially in males. The aim of this review is to discuss the detrimental effects of EDs exposure on fetal testis development, male puberty, and transition age.

METHODS

A search for the existing literature focusing on the impact of EDs on fetal testis development, male puberty, andrological parameters (anogenital distance, penile length, and testicular volume), and testicular cancer with particular regard to pubertal age provided the most current information available for this review. Human evidence-based reports were given priority over animal and in vitro experimental results. Given the paucity of available articles on this subject, all resources were given careful consideration.

RESULTS

Information about the consequences associated with EDs exposure in the current literature is limited and often conflicting, due to the scarcity of human studies and their heterogeneity.

CONCLUSIONS

We conclude that current evidence does not clarify the impact of EDs on human male reproductive health, although severe harmful effects had been reported in animals. Despite controversial results, overall conclusion points toward a positive association between exposure to EDs and reproductive system damage. Further long-term studies performed on wide number of subjects are necessary in order to identify damaging compounds and remove them from the environment.

Clinical features, presentation and hormonal parameters in patients with pubertal gynecomastia

Objective:

Gynecomastia is benign enlargement of breast in male. It is postulated that its development is primarily due to a mismatch in ratio of oestrogen and androgen at breast tissue. The aim of this study was to highlight the clinical features, presentation and hormonal parameters at the time of consultation.

Methods:

All adolescent patients who attended endocrinology department with the complaint of breast enlargement were taken into study. We analysed their thyroid function test, oestrogen, testosterone, prolactin, alpha-fetoprotein, follicle-stimulating hormone, luteinizing hormone, beta HCG (human chorionic gonadotropin) and liver function. Clinical features and anthropometry were recorded.

Results:

Out of 50 patients enrolled, 34 (68%) had bilateral gynaecomastia while 16 patients (32%) had unilateral disease. Mastalgia was seen in 44 patients (88%). Psychological disturbance in the form of depression was seen in 60% of adolescent boys with gynecomastia. Tanner stage B had positive correlation with oestrogen to testosterone (E2/TTE) ratio (r = 0.47; P = 0.034). All other hormonal parameters were normal.

Conclusion:

Mastalgia was one of the presenting complaints in majority of patients and many had bilateral enlargement. Altered oestrogen to testosterone ratio is altered in majority of patients thus may be reason for pubertal gynecomastia.

Effects of Phthalate Esters on Human Myometrial and Fibroid Cells: Cell Culture and NOD-SCID Mouse Data

Evidence is growing that phthalate esters play an important role in the pathogenesis of estrogen-dependent gynecologic diseases, especially uterine fibroids. We aimed to investigate whether in vitro treatment with di-(2-ethylhexyl)-phthalate (DEHP) affects angiogenesis, proliferation, and apoptosis in uterine fibroids. To ascertain this, we evaluated vascular endothelial growth factor (VEGF) expression and AKT/ERT phosphorylation and compared the fibroid volume between nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice fed with and without DEHP. VEGF expression was measured using enzyme-linked immunosorbent assay, and AKT/ERK phosphorylation was analyzed by western blot analysis in human myometrial and fibroid cells. The volume of the fibroid tissues implanted to NOD/SCID mice was measured, and the expression of collagen type I protein, Ki-67, proliferating cell nuclear antigen, and B cell lymphoma 2 were analyzed using immunohistochemistry. We could see significant increases in VEGF expression and AKT phosphorylation in human myometrial and fibroid cells treated with DEHP. The volume of the fibroid tissues was significantly increased in NOD/SCID mice fed with DEHP, which was accompanied by increased expression of collagen type I and AKT phosphorylation. Taken together, these results suggest that exposure to phthalate esters may influence uterine fibroid pathogenesis by increasing VEGF and collagen expression and upregulating AKT phosphorylation.

Testicular dysgenesis syndrome and phthalate exposure: A review of literature

Endocrine disruptors are chemicals that interfere with the body's endocrine system and cause adverse effects in biological systems. Phthalates are a group of man-made chemicals which are mainly used as plasticizers and classified as endocrine disruptors. They are also used in cosmetic and personal care products as color or smell fixators. Moreover, phthalates are present in inks, adhesives, sealants, automobile parts, tools, toys, carpets, medical tubing and blood storage bags, and food packages. Pathological condition known as "testicular dysgenesis syndrome" (TDS) or "phthalate syndrome" is usually linked to phthalate exposure and is coined to describe the rise in alterations in reproductive health in men, such as reduced semen quality (decrease in sperm counts, sperm motility and increase in abnormal sperms), hypospadias, cryptorchidism, reduced anogenital distance and early-life testicular cancer. Phthalates are suggested to cause direct effect on gonadal and non-gonadal tissues, impair the differentiation and morphogenesis of seminiferous tubules and accessory sex organs and testicular cells (both Sertoli and Leydig cells), alter estradiol and/or testosterone levels, decrease insulin-like 3 (INSL3) peptide production, impair spermatogenesis and lead to epigenetic alterations, all of which may lead to TDS. This review will mainly focus on phthalates as causes of TDS and their mechanisms of action.

Increased m6A modification of RNA methylation related to the inhibition of demethylase FTO contributes to MEHP-induced Leydig cell injury☆

N⁶-methyladenosine (m6A) modification, the most prevalent form of RNA methylation, modulates gene expression post-transcriptionally. Di-(2-ethylhexyl) phthalate (DEHP) is a common environmental endocrine disrupting chemical that induces testicular injury due to the inhibition of the demethylase fat mass and obesity-associated protein (FTO) and increases the m6A modification. How FTO-mediated m6A modification in testicular Leydig cell injury induced by DEHP remains unclear. Here, the TM3 Leydig cell line was treated with mono-(2-ethylhexyl) phthalate (MEHP), the main metabolite of DEHP in the body, as well as FB23-2, an inhibitor of FTO. Decreased levels of testosterone in the culture supernatant, significantly increased apoptosis, and a remarkable upregulation of global m6A modification were found in both TM3 cells treated with MEHP and FB23-2. Transcriptome sequencing showed that both treatments significantly induced apoptosis-associated gene expression. Methylated RNA immunoprecipitation sequencing showed that the Leydig cell injury induced by upregulated m6A modification could be associated with multiple physiological disorders, including histone acetylation, reactive oxygen species biosynthesis, MAPK signaling pathway, hormone secretion regulation, autophagy regulation, and male gonadal development. Overall, the inhibition of FTO-mediated up-regulation of m6A could be involved in MEHP-induced Leydig cell apoptosis.

Endocrine Disruptors and Polycystic Ovary Syndrome: Phthalates

OBJECTIVE

We aimed to investigate a possible role of the endocrine disruptors phthalates, di-2-ethylhexyl phthalate (DEHP) and mono (2-ethylhexyl) phthalate (MEHP), in polycystic ovary syndrome (PCOS) aetiopathogenesis. We also wished to evaluate the relationship between phthalates and metabolic disturbances in adolescents with PCOS.

METHODS

A total of 124 adolescents were included. Serum MEHP and DEHP levels were determined by high-performance liquid chromatography. Insulin resistance was evaluated using homeostasis model assessment-insulin resistance, quantitative Insulin Sensitivity Check Index, fasting glucose/insulin ratio, Matsuda index, and total insulin levels during oral glucose tolerance test. Participants were further subdivided into lean and obese subgroups according to body mass index (BMI).

RESULTS

Sixty-three PCOS and 61 controls, (mean age 15.2±1.5; range: 13-19 years) were enrolled. Serum DEHP and MEHP concentrations were not significantly different between PCOS and control groups. The mean (95% confidence interval) values of DEHP and MEHP were 2.62 (2.50-2.75) μg/mL vs 2.71 (2.52-2.90) μg/mL and 0.23 (0.19-0.29) μg/mL vs 0.36 (0.18-0.54) μg/mL in PCOS and the control groups respectively, p>0.05. Correlation analysis, adjusted for BMI, showed that both phthalates significantly correlated with insulin resistance indices and serum triglycerides in adolescents with PCOS.

CONCLUSION

Serum DEHP and MEHP concentrations were not different between adolescents with or without PCOS. However, these phthalates are associated with metabolic disturbances such as dyslipidemia and insulin resistance, independently of obesity, in girls with PCOS.

Marked Increase in Incident Gynecomastia: A 20-Year National Registry Study, 1998 to 2017

CONTEXT

Gynecomastia, the proliferation of mammary glandular tissue in the male, is a frequent but little-studied condition. Available prevalence data are based on selected patient populations or autopsy cases with their inherent bias.

OBJECTIVE

The objective of this work is to evaluate the age-related incidence and secular trends in gynecomastia in the general population.

DESIGN

An observational, 20-year national registry study was conducted.

SETTING

This population-based study used nationwide registry data.

PARTICIPANTS

Participants included all Danish males (age 0-80 years) with a first-time diagnosis of gynecomastia.

MAIN OUTCOME MEASURES

All Danish males (age 0-80 years) were followed up for incident diagnosis of gynecomastia in the Danish National Patient Registry from 1998 to 2017 using the International Codes of Diseases, 10th revision, and the Danish Health Care Classification System. Age-specific incidence rates were estimated. The hypothesis tested in this study was formulated prior to data collection.

RESULTS

Overall, a total 17 601 males (age 0-80 years) were registered with an incident diagnosis of gynecomastia within the 20-year study period, corresponding to 880 new cases per year and an average 20-year incidence of 3.4 per 10 000 men (age 0-80 years). The average annual incidence was 6.5/10 000 in postpubertal males age 16 to 20 years and 4.6/10 000 in males age 61 to 80 years, with a respective 5- and 11-fold overall increase in these 2 age groups over the 20-year period.

CONCLUSIONS

The incidence of gynecomastia has dramatically increased over the last 20 years, implying that the endogenous or exogenous sex-steroid environment has changed, which is associated with other adverse health consequences in men such as an increased risk of prostate cancer, metabolic syndrome, type 2 diabetes, or cardiovascular disorders.

Association of phthalate exposure with precocious and delayed pubertal timing in girls and boys: a systematic review and meta-analysis

Exposure to phthalate derivatives has adverse effects on the health and development of humans, especially for children. A growing body of evidence supports the idea that exposure to phthalates can change an individual's physiological set point and the time of puberty in both genders. In this systematic review and meta-analysis, recent studies were evaluated to obtain systematic and regulation results in relation to puberty status and phthalate exposure in girls and boys. We searched English-language papers using Scopus, ISI, and PubMed databases as search engines, with no restriction of time, until the end of July 2019. A comprehensive literature search for an association between phthalate exposure and signs of puberty as well as levels of different types of hormones was carefully performed. Of the 67 studies retained for full-text screening, 39 studies were eligible for data management and extraction. For conducting a meta-analysis, four studies had appropriate effect size and metrics for pooling in the meta-analysis. Our findings revealed that low and high exposure to phthalates could alter pubertal development in both genders; the effects were either early or delayed puberty such as changes in the pubarche, thelarche, and menarche time, as well as in testicular volume. We statistically analyzed the association of pubic-hair development, breast development, and menarche time with exposure to phthalates in girls. For example, the pooled odds ratios of mono (2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) and mono (2-ethyl-5-oxohexyl) phthalate (MEOHP) in relation to breast development were (OR: 1.48, 95% CI: 1.11-1.85) and (OR: 1.52, 95% CI: 1.15-1.58) (P-value < 0.001), respectively. In addition, we analyzed the correlation between pubic-hair development and testicular volume with exposure to phthalates in boys. To the best of our knowledge, this is the first systematic review and meta-analysis of its kind for girls and boys. In conclusion, we found that a positive association exists between phthalate exposure and pubertal timing in the pediatric age group. Therefore, prevention of exposure to phthalates and reduction of their use should be underscored in the strategies for primordial prevention of pubertal timing and related consequences.

Autophagy role in environmental pollutants exposure

During the last decades, the potential harmfulness derived from the exposure to environmental pollutants has been largely demonstrated, with associated damages ranging from geno- and cyto-toxicity to tissue malfunction and alterations in organism physiology. Autophagy is an evolutionarily-conserved cellular mechanism essential for cellular homeostasis, which contributes to protect cells from a wide variety of intracellular and extracellular stressors. Due to its pivotal importance, its correct functioning is directly linked to cell, tissue and organismal fitness. Environmental pollutants, particularly industrial compounds, are able to impact autophagic flux, either by increasing it as a protective response, by blocking it, or by switching its protective role toward a pro-cell death mechanism. Thus, the understanding of the effects of chemicals exposure on autophagy has become highly relevant, offering new potential approaches for risk assessment, protection and preventive measures to counteract the detrimental effects of environmental pollutants on human health.

Clinical and Biochemical Phenotype of Adolescent Males with Gynecomastia

OBJECTIVE

Gynecomastia is defined as a benign proliferation of male breast glandular tissue. Its prevalence during puberty varies between 50-60% and is also common in neonatal and elderly males. It develops mainly due to the disequilibrium between estrogen and androgen activity in breast tissue, where estradiol (E2) binds to estrogen receptors and stimulates ductal and glandular cells. The aim of this work was to investigate the relationship between sex hormone alterations and the natural history of gynecomastia.

METHODS

Participants in this study were young males referred to an outpatient clinic, between January 2011 and February 2016, with breast enlargement. Thyroid function, liver function, hormone concentrations and tumor markers were measured and anthropometric assessment was conducted.

RESULTS

Subjects comprised 93 males, aged 9 to 18 (mean±standard deviation age 13.8±2.6) years. In 63 of 93 (67.7%) the gynecomastia was confirmed and 28 were followed-up for a median period of three months. None of the boys showed any reduction in breast size during follow-up. There was no correlation between body mass index Z-score and breast size. Breast enlargement progressed in nine boys (32.1%). A positive correlation between estrogen to testosterone (E2/TTE) ratio and Tanner B stage (r=0.47; p=0.034) was observed.

CONCLUSION

The E2/TTE ratio may be a helpful tool in diagnosing gynecomastia. Altered E2/TTE ratio might be responsible for a proportion of cases described previously as idiopathic. Additionally, weight loss does not imply reduction of breast size in boys. Nonetheless it should be the first step in the management of prolonged gynecomastia.

Bisphenol A and phthalate levels in adolescents with polycystic ovary syndrome

Endocrine disruptors have been proposed in the etiology of polycystic ovary syndrome (PCOS) as they have the potency to interfere with hormone-sensitivity systems. The aim of this study was to evaluate the levels of bisphenol A (BPA) and phtalates in adolescents with PCOS. Sixty-two girls with PCOS and 33 controls, age 12-18 years were enrolled in the study. The diagnosis of PCOS was made using modified Rotterdam criteria. Urinary BPA levels were measured using high-performance liquid chromatography. Di-(2-ethylhexyl)-phthalate (DEHP), the most commonly used phthalate and mono-(2-ethylhexyl)-phthalate (MEHP), its main metabolite were measured by using high-performance liquid chromatography. Adolescents with PCOS had markedly increased BPA levels (15.89 μg/g creatine ± 1.16) when compared with the control group (7.30 μg/g creatine ± 1.38) (p = .016). In adolescents with PCOS, BPA was significantly correlated with polycystic morphology on ultrasound but not with obesity androgen levels, or other metabolic parameters. Patients with PCOS (DEHP: 0.40 ppm ± 0.24, MEHP: 0.13 ppm ± 0.23) and controls (DEHP: 0.49 ppm ± 0.27, MEHP: 0.14 ppm ± 0.3) had similar serum phtalate concentrations (p = .7 and p = .3, respectively). Exposure to specific endocrine disruptors such as BPA could modify neuroendocrine, reproductive, and metabolic regulation favoring PCOS development in adolescents.

A strategy to validate a selection of human effect biomarkers using adverse outcome pathways: Proof of concept for phthalates and reproductive effects

Human biomonitoring measures the concentrations of environmental chemicals or their metabolites in body fluids or tissues. Complementing exposure biomarkers with mechanistically based effect biomarkers may further elucidate causal pathways between chemical exposure and adverse health outcomes. We combined information on effect biomarkers previously implemented in human observational studies with mechanisms of action reported in experimental studies and with information from published Adverse Outcome Pathways (AOPs), focusing on adverse reproductive effects of phthalate exposure. Phthalates constitute a group of chemicals that are ubiquitous in consumer products and have been related to a wide range of adverse health effects. As a result of a comprehensive literature search, we present an overview of effect biomarkers for reproductive toxicity that are substantiated by mechanistic information. The activation of several receptors, such as PPARα, PPARγ, and GR, may initiate events leading to impaired male and female fertility as well as other adverse effects of phthalate exposure. Therefore, these receptors appear as promising targets for the development of novel effect biomarkers. The proposed strategy connects the fields of epidemiology and toxicology and may strengthen the weight of evidence in observational studies that link chemical exposures to health outcomes.

Exposure to phthalates and bisphenol A is associated with higher risk of cardiometabolic impairment in normal weight children

Some obese individuals have normal metabolic profile, and some normal-weight persons have impaired metabolic status. Our hypothesis was that one of the potential underlying factors for such differences in cardiometabolic profiles might be the exposure to some environmental chemicals. This study aimed to investigate the association of serum bisphenol A (BPA) and phthalate metabolites with cardiometabolic risk factors in children and adolescents independent of their weight status. This case-control study was conducted on a subsample of 320 participants of a national school-based surveillance program in Iran. We measured serum BPA and phthalate metabolites by gas chromatography mass spectrophotometry. We compared them in children and adolescents with and without excess weight and those with and without cardiometabolic risk factors (80 in each group). We categorized the concentrations of chemicals to tertiles and then we applied logistic regression models after adjustment for potential confounding factors. The concentrations of BPA and some metabolites of phthalates were significantly different in the four groups studied. MEHP concentration was associated with higher odds ratio of cardiometabolic risk factors in participants with normal weight (OR, 95% CI 2.82, 1.001-7.91) and those with excess weight (OR, 95% CI 3.15, 1.27-7.83). MBP concentration increased the odds ratio of cardiometabolic risk factors only in normal weight children and adolescents (OR, 95% CI 6.59, 2.33-18.59, P < 0.001). In participants without cardiometabolic risk factor, MMP and MEHHP were significantly associated with increased risk of excess weight (OR, 95% CI 5.90, 1.21-28.75 and 7.82, 1.5-41.8, respectively). This study showed that the association of BPA and phthalate with cardiometabolic risk factors is independent of the weight status. Our findings suggest that the metabolic impairment in some normal weight children and normal metabolic profile of some obese children can be, in part, related to exposure to these environmental chemicals. Graphical abstract.

A Review of Biomonitoring of Phthalate Exposures

Phthalates (diesters of phthalic acid) are widely used as plasticizers and additives in many consumer products. Laboratory animal studies have reported the endocrine-disrupting and reproductive effects of phthalates, and human exposure to this class of chemicals is a concern. Several phthalates have been recognized as substances of high concern. Human exposure to phthalates occurs mainly via dietary sources, dermal absorption, and air inhalation. Phthalates are excreted as conjugated monoesters in urine, and some phthalates, such as di-2-ethylhexyl phthalate (DEHP), undergo secondary metabolism, including oxidative transformation, prior to urinary excretion. The occurrence of phthalates and their metabolites in urine, serum, breast milk, and semen has been widely reported. Urine has been the preferred matrix in human biomonitoring studies, and concentrations on the order of several tens to hundreds of nanograms per milliliter have been reported for several phthalate metabolites. Metabolites of diethyl phthalate (DEP), dibutyl- (DBP) and diisobutyl- (DiBP) phthalates, and DEHP were the most abundant compounds measured in urine. Temporal trends in phthalate exposures varied among countries. In the United States (US), DEHP exposure has declined since 2005, whereas DiNP exposure has increased. In China, DEHP exposure has increased since 2000. For many phthalates, exposures in children are higher than those in adults. Human epidemiological studies have shown a significant association between phthalate exposures and adverse reproductive outcomes in women and men, type II diabetes and insulin resistance, overweight/obesity, allergy, and asthma. This review compiles biomonitoring studies of phthalates and exposure doses to assess health risks from phthalate exposures in populations across the globe.

Reduced camptothecin sensitivity of estrogen receptor-positive human breast cancer cells following exposure to di(2-ethylhexyl)phthalate (DEHP) is associated with DNA methylation changes

Di(2-ethylhexyl)phthalate (DEHP) has been considered as an estrogen receptor alpha (ERα) agonist due to its ability to interact with ERα and promote the cell proliferation of ERα-positive breast cancer cells. The impact of DEHP on the chemical therapy in breast cancer is little known. Two breast cancer cell lines, MCF-7 (ERα-dependent) and MDA-MB-231 (ERα-independent) were examined. We found that DEHP impaired the effectiveness of camptothecin (CPT) and alleviated the CPT-induced formation of reactive oxygen species in ERα-positive MCF-7 cells, but not in ERα-negative MDA-MB-231 cells. DEHP also significantly protected MCF-7 cells against the genotoxicity of CPT. Genome-wide DNA methylation profiling revealed that after 48 hours of exposure to 100 μM DEHP, MCF-7 cells exhibited a significant change in their DNA methylation pattern, including hypermethylation of 700 genes and hypomethylation of 221 genes. The impaired therapeutic response to CPT in DEHP-exposed MCF-7 cells is probably mediated by epigenetic changes, especially through Wnt/β-catenin signaling. A zebrafish xenograft model confirmed the disruptive effect of DEHP on CPT-induced anti-growth of MCF-7 cells. In summary, DEHP exposure induces acquired CPT-resistance in breast cancer cells and epigenetic changes associated with Wnt/β-catenin signaling activation are probably depending on an ER-positive status.

Determination of selected endocrine disruptors in organic, free-range, and battery-produced hen eggs and risk assessment

An increasing amount of evidence suggests that phthalic acid esters (PAE), polychlorinated biphenyls (PCB), polybrominated diphenyl ethers (PBDE), and organochlorine pesticides (OCP) are related to mutagenic, carcinogenic, and endocrine disruptor effects (EDCs). These lipophilic compounds are highly resistant to breakdown processes, and consequently remain in the environment, followed by uptake into the food chain. Human exposure to lipophilic compounds results from the consumption of food containing EDCs, mainly foodstuffs of animal origin with a high fat content, since these contaminants accumulate in fatty tissues. Foodstuffs in which EDCs can accumulate include meat, fish, eggs, and milk. We investigated the contamination in edible eggs to determine whether relative differences in the contaminants' residue levels appeared in three types of egg production (i.e., battery, free-range, and organic). The results showed that PAEs, especially dimethyl phthalate contamination, was the most abundant in the battery eggs, and the PCBs, PBDEs, and OCPs were the most abundant in the free-range eggs. The eggs were contaminated by more than one chemical, and as many as five contaminants (PCB180, PBDE47, dimethyl phthalate, diethyl phthalate, and di-n-butyl phthalate in battery eggs, and PCB138, PCB153, PCB180, diethyl phthalate, and di-2-ethylhexyl phthalate in organic eggs) were detected in the same egg. However, none of the chemicals detected were at the maximum limit of acceptable risk.

Is there any association between phthalate exposure and precocious puberty in girls?

Considerable increase in the prevalence of precocious puberty (PP) during the last decade has raised a lot of concerns. Some environmental endocrine disruptor chemicals (EDCs), such as phthalate esters, have intrinsic estrogen activity or increase endogenous sex hormone levels leading to PP. This study was conducted to investigate the association between exposure to phthalate esters and PP in a sample of girls. Plasma levels of seven phthalate ester metabolites were measured in 87 girls with PP and 63 age- and sex-matched controls by dispersive liquid-liquid microextraction and GC/MS analysis. History of exposure to main sources of phthalates was obtained by a checklist. Diethyl hexyl phthalate (DEHP) metabolite levels were significantly higher in those with PP than that in controls (p < 0.05), but this difference was not significant for other phthalate metabolites. 30.1% girls with PP and 12.2% of controls had played for more than 2 h/day with plastic toys in their childhood. 65.1% girls with PP and 32.8% of controls have regularly used some cosmetic products. Consumption of bottled water and beverages by those with PP was about twofold higher than that in the control group. A positive correlation was found between bottled ware consumption and plasma concentrations of four phthalate metabolites. The frequency of seafood consumption was not significantly different between the groups studied. Our findings confirm positive association between phthalate exposure and incidence of PP in girls. Control and reduction of children exposure to phthalate esters should be considered as a health priority.

Analysis of the in vitro effects of di-(2-ethylhexyl) phthalate exposure on human uterine leiomyoma cells

Uterine leiomyoma is the most common benign tumor type of the female reproductive tract. Despite its high prevalence, the exact pathogenesis of the benign tumor remains unknown. In the present study, the effects of di-(2-ethylhexyl) phthalate (DEHP) on the proliferation and apoptosis rates and expression of inflammatory proteins in human leiomyoma cells were evaluated. The effects of DEHP on cell viability were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The effects on apoptosis were evaluated by western blotting, TUNEL assay and Annexin V staining. Western blotting was also performed to evaluate the expression of inflammatory proteins. It was observed that DEHP-treated leiomyoma cells had higher viability, as well as proliferating cell nuclear antigen and B-cell lymphoma 2 protein expression, and lower apoptosis rates compared with the untreated controls. Additionally, hypoxia inducible factor 1α (HIF-1α) and cyclooxygenase-2 (COX-2) expression increased in human leiomyoma cells following DEHP treatment. In conclusion, DEHP promoted cell viability and anti-apoptotic protein expression and induced HIF-1α and COX-2 expression in human leiomyoma cells. These results suggested that DEHP may disrupt mechanisms underlying various processes in human leiomyoma cells. Furthermore, the current study revealed a basic mechanism of action of DEHP in human leiomyoma cells. Further research on the effects of various endocrine disruptors on the pathogenesis of uterine leiomyoma during early development may reveal strategies to prevent this disease.

Urinary phthalate metabolite concentrations in girls with premature thelarche

In girls, breast development before eight years of age is called "premature thelarche (PT)". There are few studies in literature that show the interaction between PT and phthalate exposure. The aim of this study was to determine the urinary levels of di-(2-ethylhexyl) phthalate (DEHP) metabolites and other phthalate metabolites in girls with PT. PT group consisted of 29 newly diagnosed subjects. Control group comprised of healthy age-matched girls (n = 25). Urinary phthalate metabolite concentrations were measured by liquid chromatography/tandem mass spectroscopy (LC-MS/MS). The urinary concentrations of mono-(2-ethyl-hexyl)phthalate (MEHP) in the PT group (33.96 ± 6.88 μg/g creatinine) were found to be significantly higher compared to control group (11.54 ± 1.39 μg/g creatinine, p = 0.002). In PT group, %MEHP was also markedly higher vs. control (17.84 ± 3.31 vs. 6.44 ± 1.13, p = 0.001). Our results suggest that DEHP is more efficiently converted to MEHP in girls with PT, the importance of which needs to be further elucidated.

Women Diagnosed with Endometriosis Show High Serum Levels of Diethyl Hexyl Phthalate

Background:

Endometriosis is one of the common causes of infertility with very diverse etiology. In modern lifestyle, humans are exposed to several endocrine-disrupting chemicals (EDCs) which may lead to reproductive disturbances. Diethyl hexyl phthalate (DEHP) is one of the common EDCs to which women are exposed by the use of cosmetics, perfumes, food packaging, medicine, and insecticides.

Aim:

The aim of this study was to measure the levels of DEHP in women diagnosed with endometriosis and healthy females and to compare these levels among different stages of endometriosis.

Setting and Design:

This descriptive study was conducted at a tertiary care hospital.

Subjects and Methods:

This study comprised of fifty women diagnosed with endometriosis, aged 20–40 years, and fifty age-matched healthy, fertile women without endometriosis. Females on any medication/comorbid conditions were excluded from the study. Serum DEHP concentrations were measured by high-performance liquid chromatography (HPLC). The results were expressed as means ± standard deviation (SD) (ng/ml of DEHP).

Statistical Analysis:

Data were analyzed using IBM-SPSS version 20. Two-sample Student's t-test and one-way ANOVA were applied for the analysis.

Results:

The mean ± SD value of DEHP in cases was 65.29 ± 21.69 ng/ml; however, the mean ± SD value of DEHP in controls was undetectable. Comparison of DEHP among stages of endometriosis revealed an increasing trend with advanced stages (III and IV). The values were not different between the two age groups of women with endometriosis (20–30 and 31–40 years).

Conclusion:

High levels of DEHP in women diagnosed with endometriosis suggest a role of phthalates in the etiology of endometriosis and permit careful use of such compounds.

Low zinc levels may contribute to gynecomastia in puberty

This study aimed to determine whether there were any differences in trace element levels between adolescent boys with gynecomastia and control boys and to determine the correlations between the levels of trace elements and body mass index (BMI) and sex hormones. The pubertal gynecomastia group comprised of 41 patients (mean age=13.2 ±0.9 years), who were admitted to Hacettepe University İhsan Doğramacı Children's Hospital in Ankara. Control group comprised of 21 healthy male children. Analyses of trace element levels were performed atomic absorption spectrometry. The mean zinc level of control group was 101.33±16.87μg/dL and the mean zinc level of gynecomastia group was 81.36±17,43μg/dL (20% lower in gynecomastia patients, p=0.0001). However, the mean copper and manganese levels of gynecomastia patients were not statistically different than the control group. There were significant positive correlations between plasma zinc and total testosterone levels in gynecomastia group (r=0.592; p<0.05). There was a significant negative correlation between plasma zinc levels and BMI (r=-0.311; p<0.05). These results indicate that zinc deficiency might be one of the underlying factors of gynecomastia, the importance of which needs to be further elucidated.

Phthalates impact human health: Epidemiological evidences and plausible mechanism of action

Disregarding the rising alarm on the hazardous nature of various phthalates and their metabolites, ruthless usage of phthalates as plasticizer in plastics and as additives in innumerable consumer products continues due low their cost, attractive properties, and lack of suitable alternatives. Globally, in silico computational, in vitro mechanistic, in vivo preclinical and limited clinical or epidemiological human studies showed that over a dozen phthalates and their metabolites ingested passively by man from the general environment, foods, drinks, breathing air, and routine household products cause various dysfunctions. Thus, this review addresses the health hazards posed by phthalates on children and adolescents, epigenetic modulation, reproductive toxicity in women and men; insulin resistance and type II diabetes; overweight and obesity, skeletal anomalies, allergy and asthma, cancer, etc., coupled with the description of major phthalates and their general uses, phthalate exposure routes, biomonitoring and risk assessment, special account on endocrine disruption; and finally, a plausible molecular cross-talk with a unique mechanism of action. This clinically focused comprehensive review on the hazards of phthalates would benefit the general population, academia, scientists, clinicians, environmentalists, and law or policy makers to decide upon whether usage of phthalates to be continued swiftly without sufficient deceleration or regulated by law or to be phased out from earth forever.

Curcumin inhibits adipogenesis induced by benzyl butyl phthalate in 3T3-L1 cells

Phthalates are a group of endocrine disrupting chemicals and may have contributed to the recent global obesity health crisis. Increased adipogenesis via the peroxisome proliferator-activated receptor γ (PPARγ)-CCAAT-enhancer binding protein α (C/EBPα) pathway could be one critical mechanism responsible for phthalate-induced weight gain. On the other hand, curcumin has been shown to inhibit adipogenesis in cells and animal models. The present study was undertaken to evaluate, for the first time, whether curcumin could reduce adipogenesis induced by benzyl butyl phthalate (BBP) via downregulation of the PPARγ-C/EBPα pathway. 3T3-L1 preadipocytes were differentiated by treating them with insulin, dexamethasone, and 3-isobutyl-1-methylxanthine in the presence of BBP, with or without curcumin. Cells that were grown in the presence of BBP alone showed a significant increase in triacylglycerol (TG) levels. In addition, the number of Oil Red O-stained cells and the mRNA expression levels of PPARγ, C/EBPα, adiponectin, and tumor necrosis factor-α (TNFα) were significantly increased. However, treatment with BBP in combination with curcumin resulted in major reductions in TG levels, the numbers of Oil Red O-stained cells, and the mRNA expression levels of the four proteins. These results suggest that curcumin might be an inhibitor of BBP-induced weight gain and inflammation via stimulation of adipocyte differentiation and TNFα generation. Curcumin may, therefore, be a potential medication for preventing the harmful effects of phthalates.

Pubertal gynecomastia: years of progress - the Hacettepe experience

Gynecomastia is defined as an enlargement of the male breast. Although it is commonly seen during puberty, it is often overlooked by many physicians. As adolescent medicine specialists, we believe there is a gap in the literature concerning both the etiology and maybe more importantly the care of these adolescents. Thus, we have been dedicated to conducting research on this topic. The aim of this review article was to evaluate the studies concerning pubertal gynecomastia that took place at the Division of Adolescent Medicine, Hacettepe University, published between the years 2003 and 2016. The review covers in detail both the short- and long-term effectivity and safety of tamoxifen used for the treatment of pubertal gynecomastia. As the exact basis for the pathogenesis of gynecomastia remains unknown, we also evaluate three studies that aimed to answer this question. We additionally review a study that aimed to assess the psychological distress and effect on body image that gynecomastia may have on the adolescent male. An important contribution this review article adds to the literature is as a conclusion to all the studies performed, we present the 'Hacettepe indications for tamoxifen treatment for pubertal gynecomastia'. These indications will aid physicians when considering treating these patients.

Prenatal and childhood exposure to phthalate diesters and sex steroid hormones in 2-, 5-, 8-, and 11-year-old children: A pilot study of the Taiwan Maternal and Infant Cohort Study

Background

Phthalate diesters are commonly used and have been well established as environmental endocrine disruptors. However, few studies have examined their effects on sex steroid hormones in children. We followed children over time to examine the association between pre- and post-natal phthalate exposure and sex steroid hormone levels at 2, 5, 8, and 11 years of age.

Methods

We recruited 430 pregnant women from central Taiwan from 2000 to 2001 and assessed their children at birth, 2, 5, 8, and 11 years of age. We studies children with at least one measurement for both phthalate and hormone levels during each any of the follow-up time point (n = 193). Estradiol, free testosterone, testosterone, and progesterone were measured from venous blood. Three monoesters of di-2-ethylhexyl phthalate (DEHP), mono-benzyl phthalate, mono-n-butyl phthalate, mono-ethyl phthalate, and mono-methyl phthalate were measured in maternal urine collected during the 3rd trimester and child urine collected at each follow-up point. The sum of mono-2-ethylhexyl phthalate (∑MEHP) was calculated by summing the concentrations of the three DEHP monoesters. Generalized estimating equation regression analysis with repeated measures was used to estimate associations between phthalate metabolites and hormone levels.

Results

After adjustment for potential confounders, maternal ∑MEHP level was associated with decreased levels of progesterone in girls (β = −0.309 p = 0.001). The child ∑MEHP concentration was associated with decreased levels of progesterone for girls (β = −0.194, p = 0.003) and with decreased levels of free testosterone for boys (β = −0.124, p = 0.004).

Conclusions

Early-life DEHP exposure may alter sex steroid hormones of children over time, which may pose potential reproductive health risks.

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Prenatal phthalate exposure was associated with decreased PG levels in girls.

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Postnatal DEHP exposure was related to decreased free TT in boys and PG in girls.

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Use of phthalate-containing products in developing children should be limited.

Adolescent gynecomastia is associated with a high incidence of obesity, dysglycemia, and family background of diabetes mellitus

BACKGROUND

Gynecomastia during adolescence is common though etiology is not clear. We studied the clinical and hormonal profile of adolescent patients with gynecomastia.

METHODOLOGY

Patients who had onset of breast development between age 10 and 20 years were included in this study. Their clinical profile, biochemical, and hormonal parameters were studied.

RESULTS

Of 94 patients with gynecomastia, 4 had hypogonadotropic hypogonadism, 4 had hypergonadotropic hypogonadism, and 1 had fibroadenosis, but in majority (90.4%), no apparent cause for breast enlargement was evident. In the idiopathic group, majority were obese (63%). Fourteen (16%) patients had impaired fasting glucose or impaired glucose tolerance. Another twenty patients had subtle abnormalities (high 1 h glucose or glucose peak at 2 h). Twenty-nine percent of lean and 38% of obese patients had mild abnormalities in glucose profile. Sixty percent of patients had family background of diabetes. Obese patients had lower testosterone as compared to lean patients; however, estradiol, luteinizing hormone, and follicle-stimulating hormone levels were similar in the two groups.

CONCLUSION

Gynecomastia during adolescence is associated with obesity, dysglycemia, and family background of diabetes mellitus.

Mammary Gland Evaluation in Juvenile Toxicity Studies: Temporal Developmental Patterns in the Male and Female Harlan Sprague-Dawley Rat

There are currently no reports describing mammary gland development in the Harlan Sprague-Dawley (HSD) rat, the current strain of choice for National Toxicology Program (NTP) testing. Our goals were to empower the NTP, contract labs, and other researchers in understanding and interpreting chemical effects in this rat strain. To delineate similarities/differences between the female and male mammary gland, data were compiled starting on embryonic day 15.5 through postnatal day 70. Mammary gland whole mounts, histology sections, and immunohistochemically stained tissues for estrogen, progesterone, and androgen receptors were evaluated in both sexes; qualitative and quantitative differences are highlighted using a comprehensive visual timeline. Research on endocrine disrupting chemicals in animal models has highlighted chemically induced mammary gland anomalies that may potentially impact human health. In order to investigate these effects within the HSD strain, 2,3,7,8-tetrachlorodibenzo-p-dioxin, diethylstilbestrol, or vehicle control was gavage dosed on gestation day 15 and 18 to demonstrate delayed, accelerated, and control mammary gland growth in offspring, respectively. We provide illustrations of normal and chemically altered mammary gland development in HSD male and female rats to help inform researchers unfamiliar with the tissue and may facilitate enhanced evaluation of both male and female mammary glands in juvenile toxicity studies.

The effect of maternal exposure to endocrine disrupting chemicals on fetal and neonatal development: A review on the major concerns

There is a widespread exposure of general population, including pregnant women and developing fetuses, to the endocrine disrupting chemicals (EDCs). These chemicals have been reported to be present in urine, blood serum, breast milk, and amniotic fluid. Endocrine disruptions induced by environmental toxicants have placed a heavy burden on society, since environmental exposures during critical periods of development can permanently reprogram normal physiological responses, thereby increasing susceptibility to disease later in life-a process known as developmental reprogramming. During development, organogenesis and tissue differentiation occur through a continuous series of tightly-regulated and precisely-timed molecular, biochemical, and cellular events. Humans may encounter EDCs daily and during all stages of life, from conception and fetal development through adulthood and senescence. Nevertheless, prenatal and early postnatal windows are the most critical for proper development, due to rapid changes in system growth. Although there are still gaps in our knowledge, currently available data support the urgent need for health and environmental policies aimed at protecting the public and, in particular, the developing fetus and women of reproductive age. Birth Defects Research (Part C) 108:224-242, 2016. © 2016 Wiley Periodicals, Inc.

Effects of long-term endocrine disrupting compound exposure on Macaca mulatta embryonic stem cells

Endocrine disrupting chemicals (EDCs) exert significant effects on health and physiology, many traceable to effects on stem cell programming underlying development. Understanding risk of low-level, chronic EDC exposure will be enhanced by knowledge of effects on stem cells. We exposed rhesus monkey embryonic stem cells to low levels of five EDCs [bisphenol A (BPA), atrazine (ATR), tributyltin (TBT), perfluorooctanoic acid (PFOA), and di-(2-ethylhexyl) phthalate (DEHP)] for 28days, and evaluated effects on gene expression by RNAseq transcriptome profiling. We observed little effect of BPA, and small numbers of affected genes (≤119) with other EDCs. There was substantial overlap in effects across two, three, or four treatments. Ingenuity Pathway analysis indicated suppression of cell survival genes and genes downstream of several stress response mediators, activation of cell death genes, and modulations in several genes regulating pluripotency, differentiation, and germ layer development. Potential adverse effects of these changes on development are discussed.

Contemporary Issues in Exposure Assessment Using Biomonitoring

In environmental epidemiology, use of biomonitoring (i.e., trace-level measurement of environmental chemicals or their metabolites in biospecimens) for exposure assessment has increased considerably in past decades. Although exposure biomarkers should reflect a person's exposure to the target chemicals (or their precursors) within a specific timeframe, timing, duration, and intensity of exposures are normally unknown and likely vary within the study period. Therefore, evaluating exposure beyond a single time point may require collecting more than one biospecimen. Of note, collection and sample processing procedures will impact integrity and usefulness of biospecimens. All of the above factors are fundamental to properly interpret biomonitoring data. We will discuss the relevance of the exposure assessment study protocol design to (a) ensure that biomonitoring specimens reflect the intended exposure, (b) consider the temporal variability of concentrations of the target biomarkers, and

Stereoselectivity and the potential endocrine disrupting activity of di-(2-ethylhexyl)phthalate (DEHP) against human progesterone receptor: a computational perspective

Di-(2-ethylhexyl)phthalate (DEHP) is a phthalate plasticizer and is one of the very common endocrine-disrupting chemicals (EDCs) contaminating our ecosystem. It is used for imparting flexibility to plastics and frequently used in personal and industrial products. Clinical and experimental studies have indicated that exposure to DEHP is associated with developmental abnormalities of the reproductive system particularly of male neonates, endometriosis and miscarriage in women, low sperm counts and lower sperm motility and DNA integrity in men, and placental problems with higher rates of low birth weight, premature birth, and fetal loss in laboratory animals. Binding of DEHP to progesterone receptor (PR) represents a potential mechanism of interference in the reproductive functions. DEHP is a chiralmolecule and is available commercially as a racemic mixture of RR, SS and RS stereoisomers. The ability of individual stereoisomers of DEHP to interfere with the reproductive functions of humans and animals is not known and molecular interactions of DEHP stereoisomers with PR are not available. In the present study, in silico approaches were adopted for molecular simulation studies of the three stereoisomers of DEHP with PR. The study suggested that all three stereoisomers of DEHP have the potential to compete with the normal substrate binding of PR. However, the binding of DEHP to PR was stereoselective with RR stereoisomer of DEHP having the best binding characteristics compared with SS, and RS stereoisomers. It has been suggested that stereoselectivity may be employed for improving the safety of the commercial compounds using pure stereoisomers instead of racemic mixtures.

Environmental endocrine disruptors: Effects on the human male reproductive system

Incidences of altered development and neoplasia of male reproductive organs have increased during the last 50 years, as shown by epidemiological data. These data are associated with the increased presence of environmental chemicals, specifically "endocrine disruptors," that interfere with normal hormonal action. Much research has gone into testing the effects of specific endocrine disrupting chemicals (EDCs) on the development of male reproductive organs and endocrine-related cancers in both in vitro and in vivo models. Efforts have been made to bridge the accruing laboratory findings with the epidemiological data to draw conclusions regarding the relationship between EDCs, altered development and carcinogenesis. The ability of EDCs to predispose target fetal and adult tissues to neoplastic transformation is best explained under the framework of the tissue organization field theory of carcinogenesis (TOFT), which posits that carcinogenesis is development gone awry. Here, we focus on the available evidence, from both empirical and epidemiological studies, regarding the effects of EDCs on male reproductive development and carcinogenesis of endocrine target tissues. We also critique current research methodology utilized in the investigation of EDCs effects and outline what could possibly be done to address these obstacles moving forward.

Could exposure to phthalates speed up or delay pubertal onset and development? A 1.5-year follow-up of a school-based population

PURPOSE

Phthalates may interfere with the timing of pubertal development in adolescence and existing studies have shown inconsistent results. This study aims to assess the associations of pubertal onset and progression with urinary concentrations of phthalate metabolites in school-aged boys and girls.

METHODS

Using isotope-dilution liquid chromatography tandem mass spectrometry, we analyzed 6 phthalate metabolites in urine samples of 430 children (222 boys and 208 girls) aged 9.7 ± 2.2 years (age range 6.1 to 13.8 years) at baseline and 18 months of follow-up. The associations of exposures to phthalates with pubertal development such as the testis, breast and pubic hair were evaluated using ordered logistic regression models, adjusting for baseline development stage, current chronological age, current body fat composition, and parental education.

RESULTS

Urinary mono-n-butyl phthalate (MnBP) was associated with a 39% increase in the odds of presenting lower pubic hair development stages in boys, and mono (2-ethylhexyl) phthalate (MEHP) (p < 0.10), mono (2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) and mono (2-ethyl-5-oxohexyl) phthalate (MEOHP) were associated with 54%-65% increase in the odds of presenting higher breast development stages in girls (p < 0.05), while MEHHP and MEOHP were also associated with a 70% increase in the odds of menarche onset (p < 0.05). After adjusting for potential confounding variables, the associations of girls' pubertal onset with MnBP, MMP, MEP and MEHP were significant. The odds of girls' breast onset were 4 to 10 times higher in high MnBP, MMP, MEP or MEHP exposure group than in low exposure group.

CONCLUSIONS

Our findings suggest subtle effects of phthalate metabolites associated with pubertal onset and progression. MnBP exposure may be associated with delayed pubic hair development in boys, while MnBP, MMP, MEP, and MEHP exposures may be associated with breast onset, and MEHP metabolites associated with speedup in breast development progression and earlier menarche onset in girls.

A Longitudinal Study of Growth, Sex Steroids, and IGF-1 in Boys With Physiological Gynecomastia

CONTEXT

Physiological gynecomastia is common and affects a large proportion of otherwise healthy adolescent boys. It is thought to be caused by an imbalance between estrogen and testosterone, although this is rarely evident in analyses of serum.

OBJECTIVE

This study aimed to describe the frequency of physiological gynecomastia and to determine possible etiological factors (eg, auxology and serum hormone levels) in a longitudinal setup.

DESIGN, SETTINGS, AND PARTICIPANTS

A prospective cohort study of 106 healthy Danish boys (5.8-16.4 years) participated in the longitudinal part of the COPENHAGEN Puberty Study. The boys were examined every 6 months during an 8-year follow-up. Median number of examinations was 10 (2-15).

MAIN OUTCOME MEASUREMENTS

Blood samples were analyzed for FSH, LH, testosterone, estradiol, SHBG, inhibin B, anti-Müllerian hormone, IGF-1, and IGF binding protein-3 by immunoassays. Auxological parameters, pubertal development, and the presence of gynecomastia were evaluated at each visit.

RESULTS

Fifty-two of 106 boys (49%) developed gynecomastia, of which 10 (19%) presented with intermittent gynecomastia. Boys with physiological gynecomastia reached peak height velocity at a significantly younger age than boys who did not develop gynecomastia (13.5 versus 13.9 years, P = .027), and they had significantly higher serum levels of IGF-1 (P = .000), estradiol (P = .013), free testosterone (P < .001), and FSH (P = .030) during pubertal transition. However, no differences in serum LH or in the estradiol to testosterone ratio were found.

CONCLUSIONS

Gynecomastia is frequent in pubertal boys. Increased IGF-1 levels and pubertal growth appear to be associated, whereas changes in estrogen to testosterone ratio seem negligible.

Association Between Urinary Phthalates and Pubertal Timing in Chinese Adolescents

BACKGROUND

Phthalates are synthetic chemicals and ubiquitous environmental contaminants, with hormonal activity that may alter the course of pubertal development in children.

OBJECTIVES

To determine whether exposure to phthalate metabolites is associated with timing of pubertal development in a cross-sectional study of a school-based clustered sample of 503 children from a suburban district in Shanghai, China, who were 7-14 years of age at enrollment (2010 October to November).

METHODS

We analyzed six phthalate metabolites in urine samples by isotope-dilution liquid chromatography tandem mass spectrometry. The associations of exposures to phthalates with pubertal timing of testes, breast, and pubic hair development (represented as Tanner stages) were evaluated using an ordered logistic regression model adjusted for chronological age, body fat proportion (BF%), and parental education.

RESULTS

In boys, urinary mono-n-butyl phthalate (MBP) levels were negatively associated with testicular volume, and mono (2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) and mono (2-ethyl-5-oxohexyl) phthalate (MEOHP) levels were negatively associated with pubic hair stages. The odds of being in an advanced stage were decreased by 43%-51%. In girls, mono (2-ethylhexyl) phthalate (MEHP), MEHHP, and MEOHP levels, as well as the sum of these levels, were positively associated with breast stages, and the association was much stronger in girls with high BF%; the odds of being in an advanced stage were increase by 29% to 50%.

CONCLUSIONS

Phthalate metabolites investigated in this study show significant associations with pubertal timing both in boys and in girls, especially among girls with high BF%.

Mono(2-ethylhexyl)phthalate accumulation disturbs energy metabolism of fat cells

Phthalates are lipophilic and tend to accumulate in adipose tissue, an important regulator of energy balance and glucose homeostasis. The study aimed to determine whether cellular phthalate accumulation influenced fat cell energy metabolism. Following a 3-day treatment with adipogenesis-inducing medium and a 2-day treatment with adipogenesis-maintaining medium, 3T3-L1 cells differentiated into adipocytes in the presence of a phthalate at a clinically relevant concentration (30-300 μM) for another 6 days. Two phthalates, di(2-ethylhexyl)phthalate and di-n-butylphthalate, and their metabolites, mono(2-ethylhexyl)phthalate (MEHP) and mono-n-butylphthalate, were used here. The phthalate treatments caused no marked effect on cytotoxicity and adipogenesis. Only the MEHP-treated adipocytes were found having smaller lipid droplets; MEHP accumulated in cells in a dose- and time-dependent manner. The MEHP-treated adipocytes exhibited significant increases in lipolysis and glucose uptake; quantitative real-time polymerase chain reaction (qPCR) analysis revealed correlated changes in expression of marker genes involved in adipogenesis, lipid metabolism, and glucose uptake. Analysis of oxygen consumption rate (a mitochondrial respiration indicator) and extracellular acidification rate (a glycolysis indicator) indicated a higher energy metabolism in the adipocytes. qPCR analysis of critical genes involved in mitochondrial biogenesis and/or energy metabolism showed that expression of peroxisome proliferator-activated receptor γ coactivator-1α, sirtuin 3, and protein kinase A were significantly enhanced in the MEHP-treated adipocytes. In vitro evidence of MEHP impacts on lipolysis, glucose uptake/glycolysis, and mitochondrial respiration/biogenesis demonstrates that MEHP accumulation disturbs energy metabolism of fat cells.

A proposal for assessing study quality: Biomonitoring, Environmental Epidemiology, and Short-lived Chemicals (BEES-C) instrument

The quality of exposure assessment is a major determinant of the overall quality of any environmental epidemiology study. The use of biomonitoring as a tool for assessing exposure to ubiquitous chemicals with short physiologic half-lives began relatively recently. These chemicals present several challenges, including their presence in analytical laboratories and sampling equipment, difficulty in establishing temporal order in cross-sectional studies, short- and long-term variability in exposures and biomarker concentrations, and a paucity of information on the number of measurements required for proper exposure classification. To date, the scientific community has not developed a set of systematic guidelines for designing, implementing and interpreting studies of short-lived chemicals that use biomonitoring as the exposure metric or for evaluating the quality of this type of research for WOE assessments or for peer review of grants or publications. We describe key issues that affect epidemiology studies using biomonitoring data on short-lived chemicals and propose a systematic instrument--the Biomonitoring, Environmental Epidemiology, and Short-lived Chemicals (BEES-C) instrument--for evaluating the quality of research proposals and studies that incorporate biomonitoring data on short-lived chemicals. Quality criteria for three areas considered fundamental to the evaluation of epidemiology studies that include biological measurements of short-lived chemicals are described: 1) biomarker selection and measurement, 2) study design and execution, and 3) general epidemiological study design considerations. We recognize that the development of an evaluative tool such as BEES-C is neither simple nor non-controversial. We hope and anticipate that the instrument will initiate further discussion/debate on this topic.