Adverse Effects of the Model environmental Estrogen DES are transmitted to subsequent Generations

The developing fetus and neonate are uniquely sensitive to exogenous estrogen exposure

Adverse Effects of the Model Environmental Estrogen Diethylstilbestrol Are Transmitted to Subsequent Generations
DES side effects in the subsequent generations

2006 Study Abstract

The synthetic estrogen diethylstilbestrol (DES) is a potent perinatal endocrine disruptor. In humans and experimental animals, exposure to DES during critical periods of reproductive tract differentiation permanently alters estrogen target tissues and results in long-term abnormalities such as uterine neoplasia that are not manifested until later in life. Using the developmentally exposed DES mouse, multiple mechanisms have been identified that play a role in its carcinogenic and toxic effects. Analysis of the DES murine uterus reveals altered gene expression pathways that include an estrogen-regulated component. Thus, perinatal DES exposure, especially at low doses, offers the opportunity to study effects caused by weaker environmental estrogens and provides an example of the emerging scientific field termed the developmental origin of adult disease. As a model endocrine disruptor, it is of particular interest that even low doses of DES increase uterine tumor incidence. Additional studies have verified that DES is not unique; when other environmental estrogens are tested at equal estrogenic doses, developmental exposure results in increased incidence of uterine neoplasia similar to that caused by DES. Interestingly, our data suggest that this increased susceptibility for tumors is passed on from the maternal lineage to subsequent generations of male and female descendants; the mechanisms involved in these transgenerational events include genetic and epigenetic events. Together, our data point out the unique sensitivity of the developing organism to endocrine-disrupting chemicals, the occurrence of long-term effects after developmental exposure, and the possibility for adverse effects to be transmitted to subsequent generations.

OVER THE LAST decade, mounting evidence from wildlife, epidemiological, laboratory animal, and in vitro studies suggests that numerous environmental and dietary chemicals can interfere with an organism’s complex endocrine signaling mechanisms and result in adverse consequences, especially alterations in reproductive tract tissues and function (1, 2, 3, 4, 5, 6). Because reduced fertility and reproductive problems are well acknowledged consequences of estrogen exposure as demonstrated by the estrogen mimics o,p′-dichlorodiphenyltrichloroethane (DDT) (7), the phytoestrogens in clover (8), and the seminal observations of the adverse effects of diethylstilbestrol (DES) on human health (9), initial concern focused on chemicals with estrogenic activity; however, it has become increasingly evident that this is not the only endocrine mode of action that merits attention. Interest has broadened to include chemicals that mimic or interfere with the normal actions of all endocrine hormones including estrogens, androgens, progestins, and thyroid, hypothalamic, and pituitary hormones; these chemicals are now collectively referred to as endocrine disruptors. With over 80,000 chemicals in commercial use in the United States alone today, only a few have been tested for endocrine-disruptor activity. It is generally assumed that most of these chemicals are not likely to pose a significant health risk at the levels of environmental exposures that exist; however, in reality, the full extent of the health consequences of these chemicals is simply unknown. Furthermore, we are just beginning to understand how chemicals act as endocrine disruptors and to appreciate the complexities of endocrine signaling mechanisms.

Sensitivity of the Developing Organism and Developmental Basis of Adult Disease:

Although adult exposure to endocrine-disrupting chemicals is important, the focus on the fetus and/or neonate is of primary concern because developing organisms are extremely sensitive to perturbation by chemicals with hormone-like activity. For example, an adverse effect may be most pronounced in the developing organism and occur at concentrations of the chemical that are far below levels that would be considered harmful in the adult. The exquisite sensitivity of the developing fetus and neonate has been described by Howard Bern in a chapter titled The Fragile Fetus (10) and is suggested to be due to numerous factors including undeveloped DNA repair mechanisms, an immature immune system, lack of detoxifying enzymes, primitive liver metabolism, lack of the development of the blood/brain barrier, and an increased metabolic rate.

Unique problems may be encountered when studying chemical exposures of the fetus and neonate undergoing critical developmental windows of differentiation. 1) Extrapolation of risks may be difficult because effects may not follow a monotonic dose-response relationship typically seen in toxicity studies; for example, higher concentrations of chemicals may show no effect, whereas lower concentrations do exhibit an effect. 2) The test chemical may have an entirely different effect in the embryo, fetus, or perinatal organism compared with effects seen in adults. 3) Effects may be manifested in offspring but not in their exposed parent. 4) Timing of exposure in the developing organism is critical in determining the final outcome in the adult organism. 5) Although critical exposure occurs during embryonic/fetal/neonatal development, manifestation of the effects may not be seen until much later in life (the developmental basis of adult disease). Developmental exposure can thus lead to a number of adverse effects in adults, which may include tumors in endocrine target tissues and adverse reproductive effects in males and females.

The scientific hypothesis that adult health and disease have an etiology arising in fetal or early neonatal development is not unique to the field of endocrine disruption. In the late 1980s, reports gained prominence by suggesting that the fetal environment, as reflected by low birth size and poor nutrition, was related to increased risk of noncommunicable diseases later in adult life; associations with coronary heart disease quickly extended to include type 2 diabetes, osteoporosis, and metabolic dysfunction (11). These findings led to the development of the developmental origins of health and disease paradigm in which a substantial research effort focused on the perinatal influences on chronic disease (12, 13, 14). Perinatal effects are no longer viewed in terms of just teratogenic changes or acute birth injury such as thalidomide-induced limb malformations, but whether changes induced in early development (preimplantation through prepubertal stages) may lead to life-long anomalies. Certainly unique problems exist in studying chemical exposures during development and their relationship to adult disease, but despite these difficulties, research findings continue to support the idea that environmental chemicals, in particular those with estrogenic activity, can have endocrine-disrupting effects that result in long-term health consequences.

As an example, the profound effects of estrogens on the developing reproductive tract have been demonstrated by prenatal exposure to DES (for review, see Refs. 15, 16, 17). Although DES effects were well recognized and firmly documented long before the proposed developmental origins of health and disease paradigm, DES clearly demonstrates that chemical exposure, in addition to nutrition and other perinatal factors, can significantly alter the developing organism and cause long-term effects in the adult.

DES as a Model Estrogenic Endocrine Disruptor:

For almost 30 yr, clinicians prescribed DES to women with high-risk pregnancies to prevent miscarriages and other complications of pregnancy. In 1971, a clinical report associated DES with a rare form of reproductive tract cancer termed vaginal adenocarcinoma, which was detected in a small number (<0.1%) of adolescent daughters of women who had taken the drug while pregnant (9). Subsequently, DES was also linked to more frequent benign reproductive tract problems in an estimated 95% of the DES-exposed daughters; reproductive organ dysfunction, abnormal pregnancies, reduced fertility, and disorders of the immune system were reported. Similarly, DES-exposed male offspring demonstrated structural, functional, and cellular abnormalities after prenatal exposure including hypospadias, microphallus, retained testes, inflammation, and decreased fertility (for review, see Ref. 17). DES became the first example of an in utero estrogenic toxicant in humans; it was shown to cross the placenta and induce a direct effect on the developing fetus. Based on the medical catastrophe it caused, DES can be viewed as the original endocrine-disrupting chemical. DES is no longer used clinically to prevent miscarriage, but a major concern remains that, as DES-exposed women age and reach the time at which the incidence of reproductive organ cancers normally increase, they will show a much higher incidence of cancer than unexposed individuals. Furthermore, the possibility of second-generation effects has been reported (18, 19, 20, 21), which puts still another generation at risk for developing problems associated with DES treatment of their grandmothers. Unfortunately, the DES episode continues to have serious health consequences and serves as a reminder of the toxicities that can be caused by hormonally active chemicals.

To study the mechanisms involved in DES-induced teratogenesis and carcinogenesis, experimental animal models were developed to study the adverse effects of developmental exposure to environmental estrogens on reproductive tract development and differentiation; these models continue to be used to study effects of other endocrine-disrupting chemicals. The high doses that were used in many of the early animal studies were similar to doses administered to pregnant women and thus have clinical relevance; lower doses are informative when using DES as a model estrogenic endocrine disruptor. The prenatal DES-exposed mouse model has been particularly successful in replicating and predicting abnormalities reported in DES-exposed humans (22, 23, 24, 25, 26, 27). A comparison of DES abnormalities (Table 1⇓) in humans and mice demonstrates the usefulness of DES-exposed experimental animal models.

Although vaginal adenocarcinoma was the original lesion of clinical interest because of its rare occurrence in young DES-exposed women, we have focused much of our research on uterine adenocarcinoma because it provides the potential to study a lesion that increases with age and occurs at a high incidence. Realizing that reproductive tract differentiation continues into neonatal life for both humans and mice, outbred CD-1 mice were treated neonatally with DES (2 μg/pup·d) on d 1–5; a high incidence of uterine cancer (90–95%) was seen in mice at 18–24 months of age (28). These tumors rarely metastasized, but in aged animals (24 months of age or older), the lesions were observed to spread to para-aortic lymph nodes or directly extended to contiguous organs (28). Investigations with other species neonatally treated with DES including rats (29) and hamsters (30) also reported a high incidence of uterine tumors. Because other experimental rodent models have duplicated uterine tumors seen in the CD-1 mouse, this lesion may be predictive of the carcinogenic potential of environmental estrogens in women as they age. It is significant that these mouse tumors progressed through the same morphological and biological continuum of hyperplasia to atypical hyperplasia to neoplasia similar to that seen in women and that the tumors were histologically similar to the human pathologies (28).

To establish a dose-response curve for uterine adenocarcinoma useful for endocrine disruptor studies, neonatal mice were treated with varying doses of DES ranging from 0.0002–2 μg/pup·d. Few studies have covered these low doses (31, 32, 34). The results showed that DES caused tumors even at a dose of 0.0002 μg/pup·d (Table 2⇓). Unlike other estrogen-responsive end points published by our lab and others that showed an inverted U dose-response relationship (33), uterine cancer followed a linear dose-dependent response with increasing incidence of tumors after increasing dose.

Interestingly, tumor incidence could be predicted based on estrogenic potency seen during neonatal life. Figure 1A⇓ shows neonatal estrogenicity in response to varying doses of DES and its relationship to subsequent carcinogenicity (Fig. 1B⇓) observed in aged mice. Both graphs show a dose-dependent linear increase, unlike some other end points that have shown nonmonotonic responses. Furthermore, DES induced estrogen-regulated genes like uterine lactoferrin (LF) on neonatal d 5, and the induction followed a similar linear response as shown by Western blotting techniques (Fig. 2⇓); thus, LF may be useful to predict future carcinogenic effects. Whether LF is directly associated with carcinogenicity or is simply a marker remains to be determined, but it is a subject of study in our laboratory.

To determine whether DES was unique or whether other environmental estrogens could cause uterine lesions, neonatal mice were similarly treated on d 1–5 with 17β-estradiol, tamoxifen, hexestrol, tetrafluorodiethylstilbestrol, ethinyl estradiol, 2-hydroxyestradiol, 4-hydroxyestradiol, genistein, nonylphenol, bisphenol A, or methoxychlor. Most of the studies were conducted using 2 μg/pup·d based on previous studies using DES; however, the weaker environmental estrogens (genistein, nonylphenol, bisphenol A, and methoxychlor) were tested at a higher dose (200 μg/pup·d). All compounds except methoxychlor caused uterine lesions in aged mice; results are summarized in Table 3⇓. Methoxychlor (pure, not technical grade) was the only compound tested that did not cause uterine lesions. Because reports in the literature suggest that a metabolite of methoxychlor is estrogenic, not methoxychlor itself (35), and because the neonatal liver is not fully functional during the time of treatment (36), the most likely explanation for lack of tumors is that the compound was not metabolized to an active estrogen form. All other compounds were estrogenic, and all were associated with uterine tumors after developmental exposure.

Uterine carcinomas have not been observed in untreated control CD-1 mice at corresponding ages, at various stages of the estrous cycle, or after similar adult short-term exposure to estrogens. This suggests that the developmental stage of uterine differentiation and the time of estrogen exposure as well as the estrogenic potency are all important factors in the development of uterine lesions.

Potential Mechanisms:

Numerous studies have demonstrated that developmental exposure to DES interferes with normal differentiation of the Müllerian duct and regression of the Wolffian duct. Although the mechanisms are not completely understood, a molecular component in the malformation of the tissues and perhaps in the cellular changes may be responsible. Developmental studies have reported that HOX genes are involved in the structural differentiation of the reproductive tract (37) and that prenatal DES delays the expression of these genes (38). Thus, this molecular misprogramming is apparently responsible for the structural alterations observed in the DES reproductive tract (39). Additional investigations with Wnt genes also suggest DES is working through multiple gene pathways to cause structural changes (40, 41, 42).

We have also described permanent abnormal gene imprinting, which may be involved in tumor induction and other cellular alterations in the reproductive tract; neonatal exposure to DES caused demethylation of the estrogen-responsive gene LF in the mouse uterus (43). Studies to determine altered methylation patterns in other estrogen-responsive genes continue.

Similar to tumors described in mice, the neonatal estrogen-exposed hamster developed uterine carcinoma at a high frequency after developmental exposure to DES (30). Molecular studies with the hamster concluded that imbalances in the estrogen-regulated uterine expression of c-jun, c-fos, c-myc, bax, bcl-2, and bcl-x protooncogenes probably played a role in the molecular mechanisms by which neonatal DES treatment ultimately induced epithelial neoplasia in the rodent uterus (44). Microarray studies with the murine uterus in our laboratory revealed similar altered gene expression pathways that included an estrogen-regulated component (Grissom, S., W. N. Jefferson, E. Padilla-Banks, E. Lobenhofer, and R. R. Newbold, submitted for publication).

The role of estrogen receptor (ER) in the induction of abnormalities and tumors after developmental DES exposure has been studied using transgenic mice that overexpressed ERα (MT-mER). MT-mER mice were treated with DES during neonatal life and followed as they aged. It was hypothesized that because of abnormal overexpression of ERα, reproductive tract tissues of the MT-mER mice might be more susceptible to tumors after neonatal DES treatment. This was indeed the case because mice overexpressing ERα were at a higher risk of developing abnormalities including uterine carcinoma in response to neonatal DES compared with DES-treated wild-type mice. At 8 months, 73% of the DES-treated MT-mER mice compared with 46% of the DES-treated wild-type mice had uterine tumors. Furthermore, these lesions occurred at an earlier age compared with wild-type DES mice (45). These transgenic mouse studies suggested that ERα levels present in a tissue may be a determining factor in the development of estrogen-related tumors. Additional transgenic mouse models that expressed variant forms of ERα, and DES-treated ER knockout mice that lacked uterine tumors, also suggested that ERα played a role in the development of reproductive tract lesions (40). ERβ was not identified in the murine uterus (46, 47); thus, its role in uterine abnormalities is unclear and requires additional study.

The role of metabolism in DES-induced lesions has long been an area of investigation. Using the DES mouse model, catechol estrogens, in particular 4-hydroxyestradiol, were very effective at uterine tumor induction (36). Although both 2- and 4-hydroxyestradiol were carcinogenic, the latter induced a 9-fold higher tumor incidence compared with the parent hormone estradiol (36). In addition to hormone-related cell proliferation that may be associated with DNA damage, 4-hydroxyestradiol can be further oxidized to a quinone reactive intermediate. Metabolic redox cycling between this quinone and the hydroquinone (4-hydroxyestradiol) may then produce mutagenic free radicals. Thus, estrogenic compounds may induce tumors in target tissues by inducing DNA damage and genetic lesions and by stimulating proliferation of cells damaged by such processes (36). Together, these data suggested that estrogens may be operating through multiple mechanisms to induce tumors.

Transgenerational Events:

Because mechanistic studies provided support that estrogens caused both genetic and epigenetic alterations in developing target tissues, the possibility was raised that abnormalities seen after prenatal or neonatal DES treatment could be transmitted to subsequent generations. In fact, studies from our laboratory showed that prenatal or neonatal treatment with DES led to tumors in the female and male genital tract, and in addition, the susceptibility for tumors was transmitted to the descendants through the maternal germ cell lineage (18, 19); transmission via the DES-exposed male was not studied. Mice were treated with DES prenatally (2.5, 5, or 10 μg/kg·d) on d 9–16 of gestation, or neonatally (0.002 μg/pup·d) on d 1–5, which were the highest doses that did not drastically interfere with fertility later in life. When female mice (F1) reached sexual maturity, they were bred to control untreated males. Female and male offspring (DES lineage or F2) from these matings were aged to 17–24 months and examined for genital tract abnormalities. An increased incidence of proliferative lesions of the rete testis (an estrogen target tissue in the male) and tumors of the reproductive tract was observed in DES-lineage males (18). Furthermore, in DES-lineage females, an increased incidence of uterine adenocarcinoma was seen (19). The incidence was lower in DES descendants than in their parents; uterine tumor incidence in DES F1 at 18 months was 31% at the neonatal dose of 0.002 (Table 2⇑), whereas it was 11% in their DES descendants (19). These data suggest that alterations occurred in germ cells and were passed to subsequent generations. Interestingly, multigenerational effects of DES have been reported by other laboratories, and some of these report transmission through the paternal lineage (21, 48).

The mechanisms involved in these transgenerational events are unknown, but altered methylation patterns can be transmitted to subsequent generations. We have shown altered methylation patterns in several uterine genes that are permanently dysregulated after developmental DES treatment (43, 49). The estrogen-responsive proteins LF and c-fos were permanently up-regulated in the uterus after developmental exposure to DES, and the promoter region of these genes was shown to be hypomethylated (43, 49). Although the consequences of these types of alterations are unclear, studies suggested that methylation patterns can be passed to subsequent generations (50). A recent report supports this theory because prenatal exposure to vinclozolin or methoxychlor caused adverse effects on testis morphology and male fertility, and these effects were transmitted to subsequent generations (51). In addition, this report showed that these two chemicals caused epigenetic alterations in the DNA, specifically hyper- and hypomethylation, and that these alterations were also observed in subsequent generations (51) (also see Anway and Skinner article in this series, Ref. 52). Because the response of estrogen-regulated genes is set during development, altered hormone response may be transmitted to subsequent generations.

Transgenerational effects may also be associated with alterations in specific estrogen-responsive genes. For example, LF induction in prepubertal females that were exposed neonatally to DES showed that this gene continued to be overexpressed even after treatment was completed (Fig. 3A⇓). Furthermore, this gene was also overexpressed in uterine tissues from DES-lineage females, although these mice never received DES (Fig. 3B⇓). Other estrogen-responsive genes are being similarly studied in DES-lineage mice, and thus far, these data suggest involvement of an altered gene expression pathway that includes an estrogen-regulated component. Future study into transgenerational effects of other environmental chemicals and the mechanisms that govern these effects is a newly emerging research focus that deserves serious attention.

Summary and Recommendations:

Sufficient evidence has been accumulated through the years in experimental animals and humans to show that the developing fetus and neonate are uniquely sensitive to exogenous estrogen exposure. If exposure occurs during critical periods of differentiation, permanent adverse effects are well documented to result. Some of these effects, such as reproductive tract abnormalities and uterine tumors, may not be observed until much later in life, long after exposure occurs. Most importantly, evidence with experimental animals suggests that adverse effects may be transmitted to subsequent generations; however, more studies are needed to determine whether this transmission of tumor potential occurs in humans. An important cohort to follow that would answer many of the unresolved questions for humans is the grandchildren of DES-exposed women. Furthermore, additional studies in both experimental animals and humans are needed to identify and understand the mechanisms involved in the transmission of disease and to detect early markers of subsequent disease.

Although animal studies must be considered carefully before extrapolation to humans follows, the DES-exposed mouse model has provided some interesting comparisons to similarly exposed humans. The model has duplicated and predicted many of the lesions observed in DES-exposed women. Although DES is a potent estrogen, it continues to provide markers of the adverse effects of exposure to estrogenic and other endocrine-disrupting substances during development, whether these exposures come from naturally occurring chemicals, from synthetic or environmental contaminants, or from pharmaceutical agents. Ongoing mechanistic studies will help identify other potential reproductive toxicants and will help better access the risks of exposure to other endocrine-disrupting chemicals in the environment if chemical exposures occur during critical stages of development.

Sources: Adverse Effects of the Model Environmental Estrogen Diethylstilbestrol Are Transmitted to Subsequent Generations
by Retha R. Newbold, Elizabeth Padilla-Banks and Wendy N. Jefferson
NCBI, June 2006 – full PDF

More DES DiEthylStilbestrol Resources

Medical Conditions among Adult Offspring prenatally exposed to DiEthylStilbestrol

DES Follow-up Study Summary

National Cancer Inst logo image
DES side-effects on Offspring exposed in Utero.

Concern about the possible impact of estrogen-like substances found in the environment on a range of health conditions has spurred research in this area. Diethylstilbestrol (DES) is an example of an endocrine-disruptor i.e., chemicals that interfere with the body’s hormone system. While prenatal exposure to DES is known to increase risks of vaginal or cervical cancer and poor reproductive outcomes in women, and abnormalities in the urinary and genital tracts in men information on non-reproductive medical conditions are lacking.

We studied the associations between prenatal DES exposure and the occurrence of cardiovascular disease, diabetes, osteoporosis and related conditions among 5,590 exposed and unexposed daughters and 2,657 exposed and unexposed sons in the NCI Combined DES Follow-up Study. The associations took into account the participants’ birth year, sex, weight adjusted for height, smoking status, alcohol use, educational status, number of general physical examinations in the past 5 years, and study site.

Comparing participants exposed prenatally to DES with those who were not exposed, there were increases in the risk of developing cardiovascular disease (27%), heart attacks (28%), hypertension (14%), and high cholesterol (12%). In addition, the risks of developing diabetes, coronary artery disease, osteoporosis and fractures were elevated, but these findings were possibly due to chance. The associations of DES and the medical conditions did not differ by dose and timing of DES exposure, nor, in the women, by presence or absence of vaginal epithelial changes (a marker of DES host susceptibility).

This study raises the possibility that prenatal DES exposure is associated with several common medical conditions in adulthood, although there is the possibility that our results are explained by differences in the reporting of conditions by the exposed and unexposed participants, or by other factors related to both the conditions and DES exposure status that were not accounted for in the study, such as dietary intake and physical activity. We plan to continue to study these associations by obtaining medical records to confirm the diagnoses in the current round of the study.

DES Info commented: ” DES Exposure estimated hazard ratios and their associated 95% confidence intervals for the associations between prenatal DES exposure and the occurrence of cardiovascular disease, diabetes, osteoporosis, and related conditions among 5590 female and 2657 male offspring followed from 1994 through 2006, adjusted for birth year, cohort, sex, body mass index, smoking status, alcohol use, education, and number of general physical examinations in the past 5 years “.

2013 Study Abstract:

BACKGROUND:
Diethylstilbestrol (DES), a synthetic estrogen that was used in pregnancy, is a prototype endocrine-disrupting chemical. Although prenatal exposure to DES is known to increase risks of vaginal/cervical adenocarcinoma and adverse reproductive outcomes in women, and urogenital anomalies in men, data on nonreproductive medical conditions are lacking.

METHODS:
We estimated hazard ratios and their associated 95% confidence intervals for the associations between prenatal DES exposure and the occurrence of cardiovascular disease, diabetes, osteoporosis, and related conditions among 5590 female and 2657 male offspring followed from 1994 through 2006, adjusted for birth year, cohort, sex, body mass index, smoking status, alcohol use, education, and number of general physical examinations in the past 5 years.

RESULTS:
Comparing persons exposed prenatally to DES with those who were not exposed, the hazard ratios were 1.21 (95% confidence interval = 0.96-1.54) for diabetes, 1.27 (1.00-1.62) for all cardiovascular disease, 1.18 (0.88-1.59) for coronary artery disease, 1.28 (0.88-1.86) for myocardial infarction, 1.12 (1.02-1.22) for high cholesterol, 1.14 (1.02-1.28) for hypertension, 1.24 (0.99-1.54) for osteoporosis, and 1.30 (0.95-1.79) for fractures. The associations did not differ by dose and timing of DES exposure, nor, in the women, by the presence or absence of vaginal epithelial changes (a marker of DES host susceptibility).

CONCLUSIONS:
These data raise the possibility that prenatal exposure to DES is associated with several common medical conditions in adulthood, although differential reporting by DES status and residual confounding cannot be ruled out. Further follow-up should assess these findings with validated outcomes and seek to understand the biological mechanisms.

Sources:

  • Medical conditions among adult offspring prenatally exposed to diethylstilbestrol,NCBI, PMID: 23474687, 2013 May;24(3):430-8. doi: 10.1097/EDE.0b013e318289bdf7. Full text link.
  • NCI, DES Follow-up Study Published Papers.
More DES DiEthylStilbestrol Resources

BPA-free Plastics going on Trial in Texas

Are BPA-free plastics really safe?

BPA-Free Plastics Going On Trial In Texas
PlastiPure helps manufacturers create water bottles and other plastic products that have no estrogenic activity

Scientists and lawyers are scheduled to debate the safety of certain “BPA-free” plastics this week in a U.S. District Court in Austin, Texas.

At issue is whether a line of plastic resins marketed by Eastman Chemical contains chemicals that can act like the hormone estrogen, and perhaps cause health problems.

Read BPA-Free Plastics Going On Trial In Texas, NPR Shots
by Jon Hamilton, 15 July 2013.

Related post:
Are BPA-free Plastics really safe?

Are BPA-free Plastics really safe?

Most Plastic Products release Estrogenic Chemicals…

Are BPA-Free Plastics Really Safe?
Scientists suspect thousands of chemicals may be estrogenically active

BPA is only part of the story. For their study, researchers tested more than 500 BPA-free consumer products for other estrogenically active chemicals and found that 92 % of the products readily leached the potentially hazardous compounds. Leaching was more common when products experienced ordinary stresses like dishwashing, microwaving and exposure to sunlight.

2011 Study Abstract

Background
Chemicals having estrogenic activity (EA) reportedly cause many adverse health effects, especially at low (picomolar to nanomolar) doses in fetal and juvenile mammals.

Objectives
We sought to determine whether commercially available plastic resins and products, including baby bottles and other products advertised as bisphenol A (BPA) free, release chemicals having EA.

Methods
We used a roboticized MCF-7 cell proliferation assay, which is very sensitive, accurate, and repeatable, to quantify the EA of chemicals leached into saline or ethanol extracts of many types of commercially available plastic materials, some exposed to common-use stresses (microwaving, ultraviolet radiation, and/or autoclaving).

Results
Almost all commercially available plastic products we sampled—independent of the type of resin, product, or retail source—leached chemicals having reliably detectable EA, including those advertised as BPA free. In some cases, BPA-free products released chemicals having more EA than did BPA-containing products.

Conclusions
Many plastic products are mischaracterized as being EA free if extracted with only one solvent and not exposed to common-use stresses. However, we can identify existing compounds, or have developed, monomers, additives, or processing agents that have no detectable EA and have similar costs. Hence, our data suggest that EA-free plastic products exposed to common-use stresses and extracted by saline and ethanol solvents could be cost-effectively made on a commercial scale and thereby eliminate a potential health risk posed by most currently available plastic products that leach chemicals having EA into food products.

BPS alters Hormones at Low Doses

Bisphenol S Disrupts Estradiol-Induced Nongenomic Signaling in a Rat Pituitary Cell Line: Effects on Cell Functions

BPA replacement alters hormones at low doses, study finds
Ultrasound images are printed on thermal paper that contains BPS

Just like the controversial Bisphenol A that it designed to replace, Bisphenol S chemical used in cash register receipts and other consumer products messes with hormones, according to research by University of Texas scientists. The study is the first to link low concentrations of BPS – a BPA alternative – to disruption of estrogen, spurring concern that it might harm human health. Researchers exposed rat cells to levels of BPS that are within the range people are exposed to…. and, just like BPA, the compound interfered with how cells respond to natural estrogen, which is vital for reproduction and other functions.

Read BPA replacement alters hormones at low doses, study finds
by Brian Bienkowski, Environmental Health News, Jan. 17, 2013.

Overall Incidence of Testicular Cancer on the Rise in the United States

Testis Cancer Rates Continue to Rise

Overall Incidence of Testicular Cancer on the Rise in the US
Testis cancer rates continue to rise

The incidence of testicular cancer has increased among American males over 15 years of age for more than 20 years and while overall incidence is still highest among Caucasian males, the greatest increase was observed in the Hispanic community, according to a new study at the 108th Annual Scientific Meeting of the American Urological Association.

DES Action USA commented: ” Experts speculate prenatal estrogen exposures may be to blame.  All men – and especially DES Sons – should practice testicular self-exam regularly!

Read Testis Cancer Rates Continue to Rise
By Charles Bankhead, MedPage Today, May 07, 2013

Sources: American Urological Association, May 03, 2013

Alterations in Estrogen Levels during Development affects the Skeleton: use of an Animal Model

Diethylstilbestrol DES side-effects on bones

Alterations in estrogen levels during development affects the skeleton: use of an animal model
DES side-effects on bones

Exposure to estrogens during various stages of development has been shown to irreversibly influence responsive target organs. The recent finding of the presence of estrogen receptor in both osteoblasts and osteoclasts has suggested a direct role of steroid hormones on bone tissue. Furthermore, estrogens have important effects on bone turnover in both humans and experimental animal models. Thus, this tissue is now regarded as a specific estrogen target tissue. To investigate whether a short-term developmental exposure to estrogens can influence bone tissue, we have injected female mice with diethylstilbestrol (DES) from day 1 through day 5 of life. Additionally, a group of pregnant female mice were injected with different doses of DES from day 9 through 16 of pregnancy. Mice were then weaned at 21 days of age, and effects on bone tissue of the female mice were evaluated in adulthood (7-12 months of age). These short-term treatments did not affect body weight of exposed mice. However, a dose-dependent increase in bone mass, both in the trabecular and compact compartments, was observed in the DES-exposed female offspring. Furthermore, femurs from DES-exposed females were shorter than femurs from controls. A normal skeletal mineralization accompanied these changes in the bone tissue. In fact, a parallel increase in total calcium content of the skeleton was found in concomitance with the increase in bone mass. Estrogen treatment induced an increase in the amount of mineralized skeleton when compared to untreated controls. In summary, this report shows that alterations of estrogen levels during development can influence the early phases of bone tissue development inducing permanent changes in the skeleton. These changes appear to be related to bone cell programming in early phases of life. ”

Abstract, NCBI Endocrinology, October 1995  – Full text here

Related post: Alterations of maternal Estrogen Levels during Gestation affect the Skeleton of Female Offspring, May 1996.

More DES DiEthylStilbestrol Resources

Alterations of maternal Estrogen Levels during Gestation affect the Skeleton of Female Offspring

DES side-effects on bones

Alterations of maternal estrogen levels during gestation affect the skeleton of female offspring
DES side-effects on bones

Estrogens have important effects on bone turnover in both humans and experimental animals models. Moreover, the decreased level of estrogen after menopause appears to be one of the key factors in determining postmenopausal osteoporosis. The presence of estrogen receptor in both osteoblasts and osteoclasts has suggested a direct role of these steroid hormones on bone tissue. Thus, this tissue is now regarded as a specific estrogen target tissue. Exposure to estrogens during various stages of development has been shown to irreversibly influence responsive target organs. We have recently shown that transient developmental neonatal exposure (days 1-5 of life) of female mice to estrogen resulted in an augmented bone density in the adult animals. The aim of the present study was to evaluate whether short-term modification of maternal estrogen levels during pregnancy would induce changes in the skeleton of the developing fetuses and to identify any long-term alterations that may occur. Pregnant mice were injected with varying doses (0.1-100 micrograms/kg maternal BW) of the synthetic estrogen diethylstilbestrol (DES) from day 9-16 of pregnancy. Offspring were weaned at 21 days of age, and effects on bone tissue of the female mice were evaluated in adulthood (6-9 months of age). Prenatal DES treatment(s) did not significantly affect BW. However, a dose-dependent increase in bone mass, both in the trabecular and cortical compartments, was observed in the prenatal DES-exposed female offspring. Furthermore, long bones of DES-exposed females were shorter than controls. Normal skeletal mineralization accompanied these changes in the bone tissue, as shown by a parallel increase in skeletal calcium content. Double tetracycline labeling performed in 6-month-old DES-exposed animals showed an increase in mineral apposition rate in adult DES-exposed mice as compared with untreated control animals, although no significant difference in the circulating estrogen levels was found in animals of this age. Experiments were then performed to evaluate whether perturbation of the estrogen surge at puberty in these diethylstilbestrol (DES)-exposed mice could reverse the observed changes. Femur length was chosen as a marker of potential estrogenic effect. Prepubertal ovariectomy of the prenatally DES-treated animals could only partially reverse the effects observed in the skeleton of the DES-treated animals. Further experiments were performed to evaluate whether these changes could have occurred in utero. CD-1 pregnant female mice were injected with DES (100 micrograms/kg maternal BW) from days 9-15 of gestation. On day 16 of gestation, fetuses were examined and stained by a standard Alizarin Red S and Alcian Blue procedure to visualize calcified and uncalcified skeletal tissue. Estrogen treatment induced an increase in the amount of calcified skeleton as compared with untreated controls and also a decrease in the length of long bones, strongly suggesting a change in both endochondral ossification and endosteal and periosteal bone formation. In summary, these data show, for the first time, that alterations in the maternal estrogenic levels during pregnancy can influence early phases of fetal bone tissue development and subsequently result in permanent changes in the skeleton. Finally, the effect of this short-term estrogen treatment can be seen in the fetal skeleton, suggesting an estrogen-imprinting effect on bone cell-programming in fetal life because treatment effects on bone cell turnover can be observed later in adult life. ”

Abstract, NCBI Endocrinology, May 1996 – Full text here

Related post: Alterations in Estrogen Levels during Development affects the Skeleton: use of an Animal Model, October 1995.

More DES DiEthylStilbestrol Resources

K-Cup® Plastic Products used under extensive Heat suspected of Estrogen Levels Rise

Cancer patients and survivors: are K-cups safe?

Cancer patients and survivors: Are K-cups safe?A sixty-year old plus friend recently shared an interesting testimony about how her estrogen levels had suddenly risen above a normal level, much to both her and her doctor’s surprise. As she began reviewing her daily eating and activity habits, she noticed only one major change in her behavior over the past several months: Since Christmas she had been regularly consuming coffee via Keurig cup containers … ”

Read Cancer patients and survivors: Are K-cups safe? pilotonline.com, Mar 31, 2013.

What about Plastics and Breast Cancer?

Choose Glass containers whenever possible!

So What About Plastics and Breast Cancer?You’ve heard stories about a compound found in plastic called BPA. It’s been linked to all sorts of health issues. So What about BPA and Breast Cancer?

BPA is an environmental estrogen, which means it increases your chances of developing breast cancer, especially when you’re exposed to it for many years.

Over time, it adds up, and this is why we see so many women, and some men, battling breast cancer today. Couple this with other ways you’re being exposed to estrogen, such as through building supplies, soy products and meat and dairy that are made from animals that have been injected with hormones.

When your body is overloaded with estrogen, your chances of breast cancer — or cancer period — are increased ; the DES-exposed know it too well…