Analysis of individual and combined estrogenic effects of bisphenol, nonylphenol and diethylstilbestrol in immature rats with mathematical models
2019 Study Abstract
Background Traditional toxicological studies focus on individual compounds. However, this single-compound approach neglects the fact that the mixture exposed to human may act additively or synergistically to induce greater toxicity than the single compounds exposure due to their similarities in the mode of action and targets. Mixture effects can occur even when all mixture components are present at levels that individually do not produce observable effects. So the individual chemical effect thresholds do not necessarily protect against combination effects, an understanding of the rules governing the interactive effects in mixtures is needed. The aim of the study was to test and analyze the individual and combined estrogenic effects of a mixture of three endocrine disrupting chemicals (EDCs), bisphenol A (BPA), nonylphenol (NP) and diethylstilbestrol (DES) in immature rats with mathematical models.
Method In the present study, the data of individual estrogenic effects of BPA, NP and DES were obtained in uterotrophic bioassay respectively, the reference points for BPA, NP and DES were derived from the dose-response ralationship by using the traditional no observed adverse effect (NOAEL) or lowest observed adverse effect level (LOAEL) methods, and the benchmark dose (BMD) method. Then LOAEL values and the benchmark dose lower confidence limit (BMDL10) of single EDCs as the dose design basis for the study of the combined action pattern. Mixed prediction models, the 3 × 2 factorial design model and the concentration addition (CA) model, were employed to analyze the combined estrogenic effect of the three EDCs.
Results From the dose-response relationship of estrogenic effects of BPA, NP and DES in the model of the prepuberty rats, the BMDL10(NOAEL) of the estrogenic effects of BPA, NP and DES were 90(120) mg/kg body weight, 6 mg/kg body weight and 0.10(0.25) μg/kg body weight, and the LOAEL of the the estrogenic effects of three EDCs were 240 mg/kg body weight, 15 mg/kg body weight and 0.50 μg/kg body weight, respectively. At BMDL10 doses based on the CA concept and the factorial analysis, the mode of combined effects of the three EDCs were dose addition. Mixtures in LOAEL doses, NP and DES combined effects on rat uterine/body weight ratio indicates antagonistic based on the CA concept but additive based on the factorial analysis. Combined effects of other mixtures are all additive by using the two models.
Conclusion Our results showed that CA model provide more accurate results than the factorial analysis, the mode of combined effects of the three EDCs were dose addition, except mixtures in LOAEL doses, NP and DES combined effects indicates antagonistic effects based on the CA model but additive based on the factorial analysis. In particular, BPA and NP produced combination effects that are larger than the effect of each mixture component applied separately at BMDL doses, which show that additivity is important in the assessment of chemicals with estrogenic effects. The use of BMDL as point of departure in risk assessment may lead to underestimation of risk, and a more balanced approach should be considered in risk assessment.
Full study (free access) : Analysis of individual and combined estrogenic effects of bisphenol, nonylphenol and diethylstilbestrol in immature rats with mathematical models, Environmental health and preventive medicine, NCBI PubMed PMC6515622, 2019 May 13.
New England Journal of Medicine, May 3, 2018 – Supported by the National Cancer Institute, National Institutes of Health, through a cooperative agreement
A new report on the risks of exposure during pregnancy to a supplement, diethylstilbestrol (DES), that is linked to a rare cancer. The study found that DES-exposed patients with clear-cell adenocarcinoma had ‘increased mortality across their life span.’ For women aged 10 to 34 with DES-related clear-cell adenocarcinoma, the risk of death was 27 times higher than for other US women in that age group.
Women who had prenatal exposure to diethylstilbestrol (DES) are at increased risk for clear-cell adenocarcinoma of the vagina and cervix early in life. Previous studies have investigated the clinical features of this disease and survival among these patients, but data on their long-term survival are lacking. Women with DES-related clear-cell adenocarcinoma are aging into their 50s and 60s, but the effect of this condition during their overall life span has not been well established.
A total of 695 patients with clear-cell adenocarcinoma in the Registry for Research on Hormonal Transplacental Carcinogenesis were followed through 2014 (see the Methods section of the Supplementary Appendix, available with the full text of this letter at NEJM.org). The mean year of birth was 1955. The mean age at diagnosis of clear-cell adenocarcinoma was 22 years, and 80% of the patients received the diagnosis between the ages of 15 and 30 years. In 415 patients, evidence of prenatal DES exposure was documented.
During a median follow-up of 22.7 years, 219 patients died, yielding a probability of 20-year survival of 69%. The 5-year probability of survival differed between the patients with prenatal DES exposure (86.1%) and patients without documentation of DES exposure (81.2%), but the 20-year probability of survival was similar between the two groups. After adjustment for tumor stage, histologic type, and age, the difference in probability of survival between patients with DES exposure and those without DES exposure was significant only in the first 5 years (P=0.025).
Since the epidemiologic curve was similar between the two groups, some of the patients with clear-cell adenocarcinoma for whom there was no documentation of DES exposure may have actually been exposed to DES in utero, and thus the true survival difference between women with DES exposure and those with idiopathic clear-cell adenocarcinoma would be larger without potential misclassification. This differential effect of DES according to time suggests that clear-cell adenocarcinoma associated with DES exposure and idiopathic clear-cell adenocarcinoma may have different tumor biologic features. Idiopathic clear-cell adenocarcinoma may be more likely to progress quickly or recur earlier, whereas clear-cell adenocarcinoma associated with DES exposure may be more likely to recur later. This interesting phenomenon has also been observed in other estrogen-associated cancers, including breast and endometrial cancers. During the first 5 to 7 years after diagnosis, patients with estrogen receptor (ER)–negative breast cancer have a worse survival than patients with ER-positive breast cancer, but the survival rates between the two groups become similar thereafter. Data from molecular studies of germline genetic mutations, tumor genomic changes, and epigenetic alterations to elucidate the underlying mechanisms for this improved behavior of estrogen-associated cancers are lacking.
We found that patients with clear-cell adenocarcinoma had increased mortality across their life span. The risk of death among women with DES-related clear-cell adenocarcinoma was 27 times higher than that in the general U.S. population of women between 10 and 34 years of age, 5 times higher between 35 and 49 years of age, and 2 times higher between 50 and 65 years of age. The excess mortality risk between the ages of 35 and 49 years is mainly due to late recurrences, whereas the excess mortality risk after 50 years of age may be due to other life-threatening health conditions in the population of women who were exposed to DES. It is therefore important to continue the surveillance of this unique cohort of patients with DES-related clear-cell adenocarcinoma to examine their health conditions late in life.
‘DES daughters’ with rare cancer continue to face higher death rates, reuters, MAY 2, 2018.
The DES saga: Death risk high for young women exposed in utero, sciencedaily, May 2, 2018.
The pill that gave a generation deadly rare cancers: Mothers-to-be took DES to avoid the pain of a miscarriage – now their daughters are paying the price, DailyMail, 3 May 2018.
Mortality Risk Persists for Cancer Tied to Prenatal DES Exposure, empr, May 04, 2018.
DES is known as a ‘biological time bomb’ and long-term effects of DES have been recorded in the mothers exposed to DES and their offspring (DES-daughters and DES-sons). Adverse pregnancy outcomes, infertility, cancer, and early menopause have been discovered in women exposed to DES, and some events occur in their offspring and subsequent generations. An increased risk of breast cancer is not limited to the DES-exposed daughters.
There is an urgent need to find ways to stop the inheritance cycle of DES and prevent adverse effects of DES in the future generations. The present article reviews the health implications of DES exposure and screening exams currently recommended to DES daughters and their offspring.
Reproductive toxicology (Elmsford, N.Y.)., Volume 71, August 2017, Pages 71–77, 2017 Apr 28. Image credit jason wilson.
Lessons from diethylstilbestrol : psychosis associated with specific methylomic modifications that could impact neurodevelopment and neuroplasticity in the DES-exposed.
2017 Study Abstract
BACKGROUND In the Western world, between 1940 and 1970, more than 2 million people were exposed in utero to diethylstilbestrol (DES). In exposed individuals, and in their descendants, adverse outcomes have been linked to such exposure, including cancers, genital malformations, and less consistently, psychiatric disorders. We aimed to explore whether prenatal DES exposure would be associated with DNA methylation changes, and whether these epigenetic modifications would be associated with increased risk of psychosis.
METHODS From 247 individuals born from mothers exposed to DES, we selected 69 siblings from 30 families. In each family, at least one sibling was exposed in utero to DES. We performed a methylome-wide association study using HumanMethylation450 DNA Analysis BeadChip® in peripheral blood. We analyzed methylation changes at individual CpGs or regions in exposed (n = 37) versus unexposed individuals (n = 32). We also compared exposed individuals with (n = 7) and without psychosis (n = 30).
RESULTS There were more individuals with schizophrenia in the DES-exposed group. We found no significant differences between exposed and unexposed individuals with respect to differentially methylated CpGs or regions. The largest difference was in a region near the promoter of an ADAMTS proteoglycanase gene (ADAMTS9). Compared to exposed individuals without psychosis, exposed individuals with psychosis had differential methylation in the region encompassing the gene encoding the zinc finger protein 57 (ZFP57).
CONCLUSIONS In utero exposure to DES was not associated with methylation changes at specific CpG or regions. In exposed individuals, however, psychosis was associated with specific methylomic modifications that could impact neurodevelopment and neuroplasticity.
Image credit Morgaine. Read and download the full study (free access) on the NCBI, PubMed, PMC5390994, 2017 Apr 13.
DES exposure results in apoptosis of spermatogonial stem cells in vitro
2017 Study Highlights
Exposure of the spermatogonial stem cells to DES produced significant increases in superoxide anion, DNA damage and apoptosis.
The male reproductive system can be disrupted by foetal exposure to DES.
The flavonoid quercetin reduced intracellular superoxide anions induced by DES.
The spermatogonial stem cells (SSCs) are the only germline stem cells in adults that are responsible for the transmission of genetic information from mammals to the next generation. SSCs play a very important role in the maintenance of progression of spermatogenesis and help provide an understanding of the reproductive biology of future gametes and a strategy for diagnosis and treatment of infertility and male reproductive toxicity.
Androgens/oestrogens are very important for the suitable maintenance of male germ cells. There is also evidence confirming the damaging effects of oestrogen-like compounds on male reproductive health.
Diethylstilbestrol induces oxidative DNA damage, resulting in apoptosis of spermatogonial stem cells in vitro, US National Library of Medicine National Institutes of Health, Toxicology, NCBI PubMed PMID: 28315349, 2017 Mar.
We investigated the effects in vitro, of diethylstilbestrol (DES) on mouse spermatogonial stem cells separated using Staput unit-gravity velocity sedimentation, evaluating any DNA damage using the Comet assay and apoptotic cells in the TUNEL assay.
Immunocytochemistry assays showed that the purity of isolated mouse spermatogonial cells was 90%, and the viability of these isolated cells was over 96%. Intracellular superoxide anion production (O2–) in SSCs was detected using p-Nitro Blue Tetrazolium (NBT) assay. The viability of cells after DES treatment was examined in the CCK8 (cell counting kit-8) cytotoxicity assay.
The study results showed that DES-induced DNA damage causes an increase in intracellular superoxide anions which are reduced by the flavonoid, quercetin. Investigating the molecular mechanisms and biology of SSCs provides a better understanding of spermatogonial stem cell regulation in the testis.
The multigeneration effect of DES provides a model to test the mechanism of transmission of cancer risk from one generation to the next
1989 Study Abstract
Animals of several species exposed perinatally to diethylstilboestrol (DES) have been evaluated for anomalies and tumours.
In male offspring, anomalies of the testis and epididymis have been reported, but evidence for tumours has been very limited.
Many anomalies and tumours have been recorded in female offspring, and some of these duplicate the anomalies and tumours reported in DES-exposed women, whereas others either have not yet been discovered or else do not occur in the human species..
Animal models of prenatal exposure to diethylstilboestrol, US National Library of Medicine National Institutes of Health, IARC scientific publications, NCBI PubMed PMID: 2680952, 1989.
A variety of abnormal physiological responses has been identified in animals exposed perinatally to DES.
There were altered levels of hormones and receptors; responses to postnatal injection of hormones were often modified; and an increased susceptibility to other carcinogens has been established.
Several mechanisms have been postulated to explain tumour production later in life after perinatal exposure to DES:
Deficiencies in immune function indicate a mechanism of impaired immune surveillance.
The presence of DES and its metabolites in the fetus and neonate raise the issue of somatic mutation. Evidence for sister chromatid exchange, cell transformation in tissue culture and other toxic effects on chromosomes support the somatic mutation hypothesis.
A third hypothesis is involvement of abnormal differentiation of the hypothalamus. Structural, hormonal and behavioural changes support this idea.
Possible additional problems in humans after exposure to DES, on the basis of animal model studies, are increased tumour frequency with ageing and transmission of cancer risk to the third generation.
The multigeneration effect of DES provides a model to test the mechanism of transmission of cancer risk from one generation to the next.
The outcome of such experiments could have considerable impact on the understanding of the association between DES and cancer specifically and transplacental cancer generally.
US National Library of Medicine National Institutes of Health, Reproductive toxicology, 2016
Epidemiological and model system studies support an early origin of reproductive dysfunction.
Estrogenic/anti-androgenic chemicals as endocrine disrupting chemicals (EDCs) have vast developmental influences on adult reproductive outcomes.
Gestational, perinatal, neonatal, and pubertal periods are “windows of susceptibility” for epigenetic programming.
EDCs induce exposure-specific epigenetic modifications in regulatory genes in organs of the reproductive system.
Germline epigenetic disruption is a mechanism underlying transgenerational inheritance of reproductive disorders.
2017 Study Abstract
Environmental factors, epigenetics, and developmental origin of reproductive disorders, US National Library of Medicine National Institutes of Health, Reproductive toxicology (Elmsford, N.Y.), NCBI PubMed PMID: 27421580, 2016 Jul.
Sex-specific differentiation, development, and function of the reproductive system are largely dependent on steroid hormones.
For this reason, developmental exposure to estrogenic and anti-androgenic endocrine disrupting chemicals (EDCs) is associated with reproductive dysfunction in adulthood.
Human data in support of “Developmental Origins of Health and Disease” (DOHaD) comes from multigenerational studies on offspring of diethylstilbestrol-exposed mothers/grandmothers.
Animal data indicate that ovarian reserve, female cycling, adult uterine abnormalities, sperm quality, prostate disease, and mating behavior are susceptible to DOHaD effects induced by EDCs such as bisphenol A, genistein, diethylstilbestrol, p,p’-dichlorodiphenyl-dichloroethylene, phthalates, and polyaromatic hydrocarbons.
Mechanisms underlying these EDC effects include direct mimicry of sex steroids or morphogens and interference with epigenomic sculpting during cell and tissue differentiation.
Exposure to EDCs is associated with abnormal DNA methylation and other epigenetic modifications, as well as altered expression of genes important for development and function of reproductive tissues.
Here we review the literature exploring the connections between developmental exposure to EDCs and adult reproductive dysfunction, and the mechanisms underlying these effects.
Significant increase of breast cancer in DES Daughters
2015 Study Abstract
OBJECTIVE To evaluate the overall cancer risk, primarily breast cancer, for women exposed to diethylstilbestrol (DES) in utero in France.
METHODS A cohort of 3 436 prenatally DES exposed women and a comparable cohort of 3256 unexposed women were recruited retrospectively from voluntary responses to questionnaires, and cases were ascertained by medical history at the time of recruitment.
Cancer Risk in Women Exposed to Diethylstilbestrol in Utero, US National Library of Medicine National Institutes of Health, Therapie, NCBI PubMed PMID: 26071143, 2015 Sep-Oct.
RESULTS One hundred ninety-five cancers were observed in exposed women (136 breast cancers, and 59 in other sites) and 141 cancers in unexposed women (90 breast cancers, and 51 others). A significant increase of breast cancers was found in exposed women, with a multivariate incidence rate ratio of 2.10 (95% CI 1.60-2.76) when compared with unexposed women. When exposed women were compared with the general population in France, the standardized incidence ratio was 2.33 (95% CI 1.93-2.72).
CONCLUSION Our results suggest a significant increase of breast cancer in prenatally DES exposed women when compared with unexposed women and with the general population. For other cancers, except clear cell carcinoma of the cervix or vagina, there was a global non-significant increase.
A national survey of DES daughters and unexposed controls
2017 Study Abstract
To explore whether prenatal exposure to diethylstilbestrol (DES) is associated with increased risk of poor psychological outcome independently of the occurrence of major somatic complications related to DES exposure.
Data on health outcome were collected in women prenatally exposed to DES (n = 2566) and unexposed women (n = 2967) recruited in a French national survey.
Women prenatally exposed to DES were 1.7 times more likely to have consulted a mental health specialist compared to unexposed women (adjusted odds ratio = 1.69, 95% confidence interval 1.47-1.96), independently of demographic characteristics, poor gynecological or obstetrical outcome, or history of cancer.
Impact of prenatal exposure to diethylstilbestrol (DES) on psychological outcome: a national survey of DES daughters and unexposed controls, US National Library of Medicine National Institutes of Health, Archives of women’s mental health, NCBI PubMed PMID: 28064340, 2017 Jan 7.
Frequency of consultation with a mental health specialist in persons with a history of gynecological complications or cancer was comparable in women prenatally exposed to DES and unexposed women.
Findings regarding psychological outcome obtained in the high-risk group of women prenatally exposed to DES may contribute to improving identification of psychological needs of all women presenting with gynecological abnormalities.
DES and estradiol monitoring using Cu-BTC frameworks-sensitized electrode
It is quite important to monitor environmental estrogens in a rapid, sensitive, simple and cost-effective manner due to their wide existence and high toxicity.
Schematic representation of the different processes and compartments that need to be monitored to characterize the fate and transport of e-EDCs in the environment via ScienceDirect.
Using 1,3,5-Benzenetricarboxylic acid (H3BTC) as the ligand and copper ions as the center, Cu-BTC frameworks with surface area of 654.6m(2)/g were prepared, and then used to construct a novel electrochemical sensing platform for diethylstilbestrol (DES) and estradiol (E2).
On the surface of Cu-BTC frameworks, two oxidation waves at 0.26V and 0.45V are observed for DES and E2, and the oxidation signals are improved greatly. The prepared Cu-BTC frameworks not only enhance the accumulation efficiency of DES and E2, but also improve their electron transfer ability. The influences of pH value, modification amount of Cu-BTC and accumulation time were examined.
Simultaneous determination of environmental estrogens: Diethylstilbestrol and estradiol using Cu-BTC frameworks-sensitized electrode, NCBI PubMed PMID: 27474301, 2016 Jun 16.
As a result, a highly-sensitive, rapid and convenient electrochemical method was developed for the simultaneous determination of DES and E2, with detection limit of 2.7nM and 1.1nM. The practical applications manifest this new sensing system is accurate and feasible.