Natural killer cells in in utero diethylstilbesterol-exposed patients

Immunotoxicology and its application in risk assessment

Immunotoxicology is the study of undesired modulation of the immune system by extrinsic factors. Toxicological assessments have demonstrated that the immune system is a target following exposure to a diverse group of xenobiotics including ultraviolet radiation, chemical pollutants, therapeutics, and recreational drugs. There is a well-established cause and effect relationship between suppression of the immune response and reduced resistance to infections and certain types of neoplasia. In humans, mild-to-moderate suppression of the immune response is linked to reduced resistance to common community-acquired infections, whereas opportunistic infections, which are very rare in the general population, are common in individuals with severe suppression. Xenobiotic exposure may also result in unintended stimulation of immune function. Although a cause and effect relationship between unintended stimulation of the immune response and adverse consequences has yet to be established, evidence does suggest that hypersensitivity, autoimmunity, and pathological inflammation may be exacerbated in susceptible populations exposed to certain xenobiotics. Xenobiotics can act as allergens and elicit hypersensitivity responses, or they can modulate hypersensitivity responses to other allergens such as pollen or dust mite by acting as adjuvants, enhancing the development or expression of hypersensitivity. Allergic contact dermatitis, allergic rhinitis, and asthma are the most commonly encountered types of hypersensitivity reactions resulting from chemical exposure. The immunologic effectors and mechanisms involved in autoimmune reactions are the same as those associated with responses to foreign antigens; however, the reactions are directed against the host's own cells. Thus, chemicals that induce immune suppression, nonspecific immunostimulation, or hypersensitivity may also impact autoimmunity. Risk assessment for immunotoxicity should be performed using the same approaches and principles for other noncancer effects. However, since xenobiotics may have effects on more than one aspect of immune function, immunotoxicity data should be evaluated separately for evidence of suppression, stimulation, hypersensitivity, and autoimmunity.

Exposure to diethylstilbestrol during pregnancy modulates microRNA expression profile in mothers and fetuses reflecting oncogenic and immunological changes

Prenatal exposure to diethylstilbestrol (DES) is known to cause an increased susceptibility to a wide array of clinical disorders in humans. Previous studies from our laboratory demonstrated that prenatal exposure to DES induces thymic atrophy and apoptosis in the thymus. In the current study, we investigated if such effects on the thymus result from alterations in the expression of microRNA (miR). To that end, pregnant C57BL/6 mice who were exposed to DES and miR profiles in thymocytes of both the mother and fetuses on postnatal day 3 (gestation day 17) were studied. Of the 609 mouse miRs examined, we noted 59 altered miRs that were common for both mothers and fetuses, whereas 107 altered miRs were specific to mothers only and 101 altered miRs were specific to fetuses only. Upon further analyses in the fetuses, we observed that DES-mediated changes in miR expression may regulate genes involved in important functions, such as apoptosis, autophagy, toxicity, and cancer. Of the miRs that showed decreased expression following DES treatment, miR-18b and miR-23a were found to possess complementary sequences and binding affinity for 3' untranslated regions of the Fas ligand (FasL) and Fas, respectively. Transfection studies confirmed that DES-mediated downregulation of miR-18b and miR-23a led to increased FasL and Fas expression. These data demonstrated that prenatal DES exposure can cause alterations in miRs, leading to changes in the gene expression, specifically, miR-mediated increased expression in FasL and Fas causing apoptosis and thymic atrophy.

Occurrences of six steroid estrogens from different effluents in Beijing, China

Concentration levels of six natural and anthropogenic origin steroid estrogens, namely, diethylstilbestrol (DES), estrone (E1), estradiol (E2), estriol (E3), ethinylestradiol (EE2), and estradiol-17-valerate (Ev), from different effluents in Beijing were assessed. Sampling sites include two wastewater treatment plants (WWTPs), a chemical plant, a hospital, a pharmaceutical factory, a hennery, and a fish pool. In general, concentrations of estrogens in the effluents varied from no detection (nd) to 11.1 ng/l, 0.7 to 1.2 × 10(3) ng/l, nd to 67.4 ng/l, nd to 4.1 × 10(3) ng/l, nd to 1.2 × 10(3) ng/l, and nd to 11.2 ng/l for DES, E1, E2, EE2, E3, and Ev, respectively. The concentration levels of steroid estrogens from different effluents decreased in the order of pharmaceutical factory and WWTP inlets > hospital > hennery > chemical factory > fish pool. This study indicated that natural estrogens E1, E2, and E3 and synthetic estrogen EE2 are the dominant steroid estrogens found in the different Beijing effluents. For source identification, an indicator (hE = E3/(E1 + E2 + E3)) was used to trace human estrogen excretion. Accordingly, hE in effluents from the hospital and WWTP inlets exceeded 0.4, while much smaller values were obtained for the other effluents. Human excretions were the major contributor of natural estrogens in municipal wastewater. Estimation results demonstrated that direct discharge was the major contributor of steroid estrogen pollution in receiving waters.

The association of maternal factors with delayed implantation and the initial rise of urinary human chorionic gonadotrophin

BACKGROUND Late implantation and the pattern of early rise in hCG have been associated with early pregnancy loss. We explored factors that might be predictive of these markers of poor embryonic health in spontaneously conceived pregnancies. METHODS Participants in the North Carolina Early Pregnancy Study collected daily first-morning urine specimens while attempting to conceive. Samples were assayed for estrogen and progesterone metabolites (to identify day of ovulation) and hCG (to detect conception). Data were available for 190 pregnancies, 48 of which ended in early loss (within 6 weeks of the last menstrual period). We used logistic regression to identify characteristics associated with late implantation (≥10 days post-ovulation). For pregnancies surviving at least 6 weeks (n= 142), we used linear mixed models to identify factors associated with variations in hCG rise in the first 7 days from detection. RESULTS Later implantation was associated with current maternal smoking [odds ratio (OR): 5.7; 95% confidence interval (CI): 1.1-30] and with oocytes that were likely to have been fertilized late in their post-ovulatory lifespan (OR: 5.1; CI: 1.9-16). Older women had a faster rise in hCG (P= 0.01), as did women who had relatively late menarche (P for trend = 0.02). Women exposed in utero to diethylstilbestrol showed an unusual pattern of slow initial hCG rise followed by a fast increase, a pattern significantly different from that of unexposed women (P= 0.002). CONCLUSIONS Although limited by small numbers and infrequent exposures, our analyses suggest that a woman's exposures both early in life and at the time of pregnancy may influence early development of the conceptus.

Preeclampsia Risk in Women Exposed in Utero to Diethylstilbestrol

OBJECTIVE

To assess whether preeclampsia risk is elevated in pregnancies of diethylstilbestrol (DES)-exposed daughters.

METHODS

This study used data from the National Cancer Institute DES Combined Cohorts Follow-up Study. A total of 285 preeclampsia cases (210 exposed and 75 unexposed) occurred in 7,313 live births (4,759 DES exposed and 2,554 unexposed). Poisson regression analysis estimated relative risks and 95% confidence intervals (CI) for preeclampsia adjusted for age at the index pregnancy, parity, education, smoking, body mass index, year of diagnosis, and cohort.

RESULTS

In utero DES exposure was associated with nearly a 50% elevation in preeclampsia risk. Adjustment for preeclampsia risk factors attenuated the relative risk slightly (1.42, 95% CI 1.04-1.94). The excess risk with DES was concentrated among women who developed preeclampsia in their first pregnancies (relative risk 1.81, 95% CI 1.17-2.79), who were exposed before 15 weeks of gestation (relative risk 1.57, 95% CI 1.11-2.23), and who were treated with magnesium sulfate (relative risk 2.10, 95% CI 0.82-5.42). Among DES-exposed women who had a prior hysterosalpingogram, preeclampsia prevalence was higher in those with uterine abnormalities (12.4%) than in those without (7.7%).

CONCLUSION

These data suggest that in utero exposure to DES is associated with a slightly elevated risk of preeclampsia, and that one possible biological mechanism involves uterine abnormalities.

Diethylstilbestrol alters positive and negative selection of T cells in the thymus and modulates T-cell repertoire in the periphery

Prenatal exposure to diethylstilbestrol (DES) is known to cause altered immune functions and increased susceptibility to autoimmune disease in humans. In the current study, we investigated the effects of DES on T-cell differentiation in the thymus using the HY-TCR transgenic (Tg) mouse model in which the female mice exhibit positive selection of T cells bearing the Tg TCR, while the male mice show negative selection of such T cells. In female HY-TCR-Tg mice, exposure to DES showed more pronounced decrease in thymic cellularity when compared to male mice. Additionally, female mice also showed a significant decrease in the proportion of double-positive (DP) T cells in the thymus and HY-TCR-specific CD8+ T cells in the periphery. Male mice exhibiting negative selection also showed decreased thymic cellularity following DES exposure. Moreover, the male mice showed increased proportion of double-negative (DN) T cells in the thymus and decreased proportion of CD8+ T cells. The density of expression of HY-TCR on CD8+ cells was increased following DES exposure in both females and males. Finally, the proliferative response of thymocytes to mitogens and peripheral lymph node T cells to male H-Y antigen was significantly altered in female and male mice following DES treatment. Taken together, these data suggest that DES alters T-cell differentiation in the thymus by interfering with positive and negative selection processes, which in turn modulates the T-cell repertoire in the periphery.

Genistein modulates immune responses and increases host resistance to B16F10 tumor in adult female B6C3F1 mice

The isoflavone genistein (4,7,4'-trihydroxyisoflavone) is a phytoestrogen found in high levels in soy products that has been associated with decreased incidences of breast and prostate cancers. The potential effects of genistein on the immune system were evaluated in adult female B6C3F1 mice. Groups of mice were exposed to vehicle or genistein by gavage for 28 d. The doses of genistein used were 2, 6 and 20 mg/kg body. Consistent with the chemopreventive effect of genistein, exposure to this compound significantly increased host resistance to B16F10 tumor as reflected by a decrease in the number of lung tumor nodules after tumor cell injection at the middle and high dose levels. Inhibition of B16F10 tumor formation was not due to a direct effect of serum genistein and/or its metabolites on the proliferation of B16F10 tumor cells. When innate and acquired immune responses were evaluated, a dose-related increase of cytotoxic T-cell activity was observed in genistein-treated mice with significant changes observed at the middle and high dose levels. Furthermore, in vitro interleukin (IL)-2-stimulated natural killer (NK) cell activity was significantly enhanced in the high genistein dose group, although the basal NK cell activity was not affected. Although no affect on the mixed lymphocyte responses and anti-CD3 antibody-mediated splenocyte proliferation was observed, exposure to genistein significantly increased basal splenocyte proliferation. Exposure to genistein did not alter the activity of the mononuclear phagocyte system and the cytotoxic/cytostatic function of thioglycollate-recruited peritoneal cells on B16F10 tumor cells. Finally, exposure to genistein did not produce biologically meaningful changes in spleen immunoglobulin (Ig)M and IgG antibody-forming cell responses. In conclusion, genistein enhanced host resistance as evaluated in the B16F10 tumor model, which may be related to the increases in the activities of cytotoxic T cells and NK cells.

Effect of diethylstilbestrol on reproductive function

OBJECTIVE

To review the effects of in utero exposure to diethylstilbestrol (DES) on müllerian development and subsequent reproductive function.

DESIGN

The literature on DES and reproductive function was reviewed and summary data are presented. The studies were identified through the computerized MEDLINE database and a manual search of relevant bibliographies.

RESULT(S)

In utero exposure to DES resulted in reduced fertility and increased rates of ectopic pregnancy, spontaneous abortion, and preterm delivery.

CONCLUSION(S)

An understanding of the reproductive performance of women who were exposed to DES in utero is useful for counseling these patients regarding their risks and treatment options.

Prenatal diethylstilbestrol exposure and self-reported immune-related diseases

OBJECTIVE

To compare self-reports of immune-related diseases in diethylstilbestrol (DES) daughters and controls. Prenatal exposure to DES has been associated with several malformations in the lower genital tract, a higher prevalence of adenosis, and increased risk of clear cell adenocarcinoma, and estrogen-dependent tumors. Lately, reports have been published indicating a link between DES exposure and alterations in the immune system. The present study focuses on the possible clinical consequences of an affected immune system.

STUDY DESIGN

DES daughters (n=170) and control women (n=123) completed questionnaires containing lists of immune-related diseases, specified into three categories (i) allergies, (ii) auto-immune disorders, and (iii) infectious diseases.

RESULTS

DES daughters reported significantly more disease conditions than the controls. Analyses for separate disease categories (allergies, auto-immune disorders, infectious disease), yielded a statistically significant difference only for infectious disease. Within this last category, two infectious diseases yielded highly significant differences: bladder infection and measles.

CONCLUSION

The present findings suggest that DES daughters are at higher risk of developing immune-related disease states.

Environmental endocrine modulators and human health: an assessment of the biological evidence

Recently, a great deal of attention and interest has been directed toward the hypothesis that exposure, particularly in utero exposure, to certain environmental chemicals might be capable of causing a spectrum of adverse effects as a result of endocrine modulation. In particular, the hypothesis has focused on the idea that certain organochlorine and other compounds acting as weak estrogens have the capability, either alone or in combination, to produce a variety of adverse effects, including breast, testicular and prostate cancer, adverse effects on male reproductive tract, endometriosis, fertility problems, alterations of sexual behavior, learning disability or delay, and adverse effects on immune and thyroid function. While hormones are potent modulators of biochemical and physiological function, the implication that exposure to environmental hormones (e.g., xenoestrogens) has this capability is uncertain. While it is reasonable to hypothesize that exposure to estrogen-like compounds, whatever their source, could adversely affect human health, biological plausibility alone is an insufficient basis for concluding that environmental endocrine modulators have adversely affected humans. Diethylstilbestrol (DES) is a potent, synthetic estrogen administered under a variety of dosing protocols to millions of women in the belief (now known to be mistaken) that it would prevent miscarriage. As a result of this use, substantial in utero exposure to large numbers of male and female offspring occurred. Numerous studies have been conducted on the health consequences of in utero DES exposure among the adult offspring of these women. There are also extensive animal data on the effects of DES and there is a high degree of concordance between effects observed in animals and humans. The extensive human data in DES-exposed cohorts provide a useful basis for assessing the biological plausibility that potential adverse effects might occur following in utero exposure to compounds identified as environmental estrogens. The effects observed in both animals and humans following in utero exposure to sufficient doses of DES are consistent with basic principles of dose response as well as the possibility of maternal dose levels below which potential non-cancer effects may not occur. Significant differences in estrogenic potency between DES and chemicals identified to date as environmental estrogens, as well as an even larger number of naturally occurring dietary phytoestrogens, must be taken into account when inferring potential effects from in utero exposure to any of these substances. The antiestrogenic properties of many of these same exogenous compounds might also diminish net estrogenic effects. Based on the extensive data on DES-exposed cohorts, it appears unlikely that in utero exposure to usual levels of environmental estrogenic substances, from whatever source, would be sufficient to produce many of the effects (i.e., endometriosis, adverse effects on the male reproductive tract, male and female fertility problems, alterations of sexual behavior, learning problems, immune system effects or thyroid effects) hypothesized as potentially resulting from exposure to chemicals identified to date as environmental estrogens.

Self-reported allergy, infection, and autoimmune diseases among men and women exposed in utero to diethylstilbestrol

Immunotoxicology studies of prenatal or neonatal exposure to diethylstilbestrol (DES) show effects on immune function of the adult animal. Prenatally exposed humans are known to be at increased risk of vaginal adenocarcinoma, but little research has been done to assess immunologic function. A placebo-controlled clinical trial of DES was conducted in the early 1950s. The sons and daughters born to participants of this clinical trial were traced and interviewed about immune-related health problems. Symptom and disease rates for the DES exposed (253 sons and 296 daughters) were compared with rates for the unexposed (241 men and 246 women). DES-exposed men and women reported rates of allergy, infection, and autoimmune disease similar to the unexposed. However, because autoimmune diseases are rare, a larger sample is needed to evaluate further DES-associated risk of autoimmunity.