Bisphenol A and congenital developmental defects in humans.

Over 50% of the causes of fetal malformations in humans are still unknown. Recent evidence suggests the relationship between environmental exposure to endocrine disruptors and fetal malformations. Our study aims to establish the role of Bisphenol A (BPA), if any, in altering human reproduction. We enrolled 151 pregnant women who were divided into two groups: case group (CS, n=101), women with established diagnosis of developmental defect, and control group (CL, n=50), pregnant women with normally developed fetus. Total, free and conjugated BPA were measured in their blood using GC-MS with isotopic dilution. The results show a correlation between environmental exposure to BPA and the genesis of fetal malformations. Conjugated BPA, which was higher in the CL, casts light on the hypothesis that a reduced ability to metabolize the chemical in the mother can concur to the occurrence of malformation. In a more detailed manner, in case of chromosomal malformations, the average value of free BPA appears to be nearly three times greater than that of the controls. Similarly, in case of central and peripheral nervous system non-chromosomal malformations, the value of free BPA is nearly two times greater than that of the controls.

Measurement of phenolic environmental estrogens in human urine samples by HPLC-MS/MS and primary discussion the possible linkage with uterine leiomyoma.

A method was established for the determination of three phenolic environmental estrogens, namely bisphenol A (BPA), nonylphenol (NP) and octylphenol (OP), in urine from women of uterine leiomyoma group (n=49) and control group (n=29), by using solid-phase extraction (SPE) coupled with liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Urine samples were spiked with 2,4,6-tribromophenyl-terminated tetrabromobisphenol-A carbonate oligomer (TBBPA) and nonylphenol D8 (NP-D8) as internal standard (I.S.) and de-conjugated by adding ß-glucuronidase and sulfatase before the SPE. The extraction recoveries of BPA, NP and OP were more than 73.3%; the standard curve was linear over the validated concentrations in the range of 1.0-100.0ng/mL and the limits of detection (LOD) of BPA, NP and OP were 0.32ng/mL, 0.18ng/mL and 0.15ng/mL, respectively. Moreover, by analysing quality control urine samples in 5 days, the results showed that the method was precise and accurate, for the intra- and inter-day CV% within 15.2%. Except that OP was not found (3). NP levels were significantly higher in uterine leiomyoma patients than control group in low gravidity subgroup. Though BPA levels in experimental and control groups were not significantly different, the mean levels and concentration distribution were different. The study suggested that there is certain relationship between exposure concentrations of phenolic environmental estrogens and uterine leiomyoma disease.

Aromatase expression in leptin-pretreated human breast pre-adipocytes is enhanced by zeranol and suppressed by (-)-gossypol.

BACKGROUND: Obesity is associated with an increased risk of estrogen-dependent breast cancer. Recently, concerns have been raised regarding the role of zeranol (Z), a non-steroidal anabolic growth promoter with potent estrogenic activity widely used in the U.S.A. beef industry, as a possible contributor to an increased incidence of human breast cancer. This study hypothesized that obese individuals may be at greater risk of developing zeranol-induced breast cancer. MATERIALS AND METHODS: The aromatase mRNA expression level of three cell types isolated from adipose tissues were assayed by RT-PCR, and the cell proliferation of primary cultured human normal breast pre-adipocytes (HNBPADs) was investigated using the CellTiter96® non-radioactive method. The effects of Z and gossypol on aromatase expression of leptin-pretreated HNBPADs were evaluated by RT-PCR. RESULTS: HNBPADs expressed higher aromatase than primary cultured human breast epithelial cells and stromal cells. Z enhanced the mitogenic activity of leptin and increased aromatase expression in HNBPADs. Moreover, (-)-gossypol counteracted Z- and leptin-induced cell proliferation and aromatase expression. CONCLUSION: These results suggested that bioactive Z metabolites contained in meat produced from Z-implanted beef cattle may increase estrogen biosynthesis in obese individuals by increasing aromatase expression and estrogen production, which will promote cell sensitivity and increase breast cancer cell growth.

Endocrine disruptors.

Man does not come into the world pre-determined. The lifetime set of environmental conditions impinging on a given individual has been termed the ambiome, which together with the genome and the proteome determines each individual's development and construction. Among the most important elements making up the ambiome are endocrine disruptors. An endocrine disruptor is a chemical substance that has adverse effects on an organism or its progeny, through the endocrine system. The number of known endocrine disruptors is large and continuously increasing, and includes both naturally occurring and synthetic substances. We are convinced that they entail genuine problems; although it is difficult to assess their magnitude and real significance, and we will certainly need some time, probably several decades, to obtain conclusive results; but even so, we consider that the existing body of evidence about effects of endocrine disruptors on human health is sufficiently worrying to justify precautionary measures.

[Molecular mechanisms of environmental estrogens on reproductive and developmental toxicity].

It has been shown that numerous natural and synthetic chemicals with estrogenic activities are reproductive or developmental toxic factors in humans or animals by epidemiological investigations and animal experiments. The mechanisms of toxicity, however, are very complicated, especially the molecular mechanisms. This article introduced the current progress on molecular mechanisms of toxicity, which included modulating signaling pathways, interfering gene expression during embryo stage, inducing mutation, etc.

Feed and forage toxicants affecting embryo survival and fetal development.

Early embryonic and fetal development in mammals is sensitive to deficiencies and excesses of specific nutrients and toxicants. Operating directly and/or indirectly, these deficiencies and excesses can result in embryonic death or, in less severe circumstances, disruption of normal embryo and fetal growth. This paper explores the threats posed by feed and forage toxicants to the developing embryo and their impact on early programming of fetal development. Using significant examples, we consider the relevance of temporal sensitivities during early development in utero, and their implications for the morphology and functional competence of specific organs and tissues.