Effects of maternal chlorpyrifos diet on social investigation and brain neuroendocrine markers in the offspring - a mouse study.

BACKGROUND: Chlorpyrifos (CPF) is one of the most widely used organophosphate pesticides worldwide. Epidemiological studies on pregnant women and their children suggest a link between in utero CPF exposure and delay in psychomotor and cognitive maturation. A large number of studies in animal models have shown adverse effects of CPF on developing brain and more recently on endocrine targets. Our aim was to determine if developmental exposure to CPF affects social responsiveness and associated molecular neuroendocrine markers at adulthood. METHOD: Pregnant CD1 outbred mice were fed from gestational day 15 to lactation day 14 with either a CPF-added (equivalent to 6 mg/kg/bw/day during pregnancy) or a standard diet. We then assessed in the offspring the long-term effects of CPF exposure on locomotion, social recognition performances and gene expression levels of selected neurondocrine markers in amygdala and hypothalamus. RESULTS: No sign of CPF systemic toxicity was detected. CPF induced behavioral alterations in adult offspring of both sexes: CPF-exposed males displayed enhanced investigative response to unfamiliar social stimuli, whereas CPF-exposed females showed a delayed onset of social investigation and lack of reaction to social novelty. In parallel, molecular effects of CPF were sex dimorphic: in males CPF increased expression of estrogen receptor beta in hypothalamus and decreased oxytocin expression in amygdala; CPF increased vasopressin 1a receptor expression in amygdala in both sexes. CONCLUSIONS: These data indicate that developmental CPF affects mouse social behavior and interferes with development of sex-dimorphic neuroendocrine pathways with potential disruptive effects on neuroendocrine axes homeostasis. The route of exposure selected in our study corresponds to relevant human exposure scenarios, our data thus supports the view that neuroendocrine effects, especially in susceptible time windows, should deserve more attention in risk assessment of OP insecticides.

Exposure to endocrine disrupters and nuclear receptor gene expression in infertile and fertile women from different Italian areas.

Within the PREVIENI project, infertile and fertile women were enrolled from metropolitan, urban and rural Italian areas. Blood/serum levels of several endocrine disrupters (EDs) (perfluorooctane sulfonate, PFOS; perfluorooctanoic acid, PFOA; di-2-ethylhexyl-phthalate, DEHP; mono-(2-ethylhexyl)-phthalate, MEHP; bisphenol A, BPA) were evaluated concurrently with nuclear receptors (NRs) gene expression levels (ERa, ERb, AR, AhR, PPARg, PXR) in peripheral blood mononuclear cells (PBMCs). Infertile women from the metropolitan area displayed significantly higher levels of: BPA compared to fertile women (14.9 vs. 0.5 ng/mL serum); BPA and MEHP compared to infertile women from urban and rural areas; enhanced expression levels of NRs, except PPARg. Infertile women from urban and rural areas had PFOA levels significantly higher than those from metropolitan areas. Our study indicates the relevance of the living environment when investigating the exposure to EDs and the modulation of the NR panel in PBMC as a suitable biomarker of the effect, to assess the EDs impact on reproductive health.

Correlation of endocrine disrupting chemicals serum levels and white blood cells gene expression of nuclear receptors in a population of infertile women.

Significant evidence supports that many endocrine disrupting chemicals could affect female reproductive health. Aim of this study was to compare the internal exposure to bisphenol A (BPA), perfluorooctane sulphonate (PFOS), perfluorooctanoic acid (PFOA), monoethylhexyl phthalate (MEHP), and di(2-ethylhexyl) phthalate (DEHP) in serum samples of 111 infertile women and 44 fertile women. Levels of gene expression of nuclear receptors (ER α , ER ß , AR, AhR, PXR, and PPAR γ ) were also analyzed as biomarkers of effective dose. The percentage of women with BPA concentrations above the limit of detection was significantly higher in infertile women than in controls. No statistically significant difference was found with regard to PFOS, PFOA, MEHP and DEHP. Infertile patients showed gene expression levels of ER α , ER ß , AR, and PXR significantly higher than controls. In infertile women, a positive association was found between BPA and MEHP levels and ER α , ER ß , AR, AhR, and PXR expression. PFOS concentration positively correlated with AR and PXR expression. PFOA levels negatively correlated with AhR expression. No correlation was found between DEHP levels and all evaluated nuclear receptors. This study underlines the need to provide special attention to substances that are still widely present in the environment and to integrate exposure measurements with relevant indicators of biological effects.

The influence of endocrine disruptors in a selected population of infertile women.

Several studies report that endocrine disrupting chemicals (EDC) able to interfere with endocrine homeostasis may affect women's reproductive health. We analyzed EDC serum levels and nuclear receptors (NRs) expression in order to have an indication of the internal dose of biologically active compounds and a measurement of indicators of their effects, as a result of the repeated uptake from environmental source. The percentage of patients with detectable bisphenol A (BPA) concentrations was significantly higher in the infertile patients compared with fertile subjects. No significant difference was found between the groups with regard to perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), mono-ethylhexyl phthalate (MEHP) and di-(2-ethylhexyl) phthalate (DEHP) concentrations. Among infertile women, the mean expression of estrogen receptor alpha (ERα) and beta (Erß), androgen receptor (AR) and pregnane X receptor (PXR) was significantly higher than fertile patients. The mean expression of aryl hydrocarbon receptor (AhR) and peroxisome proliferator-activated receptor gamma (PPARγ) did not show significant differences between two groups. Patients with endometriosis had higher levels of PPARγ than all women with other causes of infertility. This study led further support to EDC exposure as a risk factor for women's fertility.

Exposure and effective dose biomarkers for perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) in infertile subjects: preliminary results of the PREVIENI project.

Perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) have been used as surfactants in various industry and consumer products. PFOS/PFOA are very persistent in the environment and bioaccumulate in humans. They are potential reproductive and developmental toxicants and are considered to be emerging endocrine disrupters (EDs). The Italian project PREVIENI, funded by the Italian Environment Ministry, aims to link environment and human health through the investigation of selected endocrine disrupters (EDs) exposure and associated biomarkers related to human infertility conditions. In the early PREVIENI phase, PFOS and PFOA were determined in 53 couples affected by an infertility status, enrolled in a metropolitan area, according to established inclusion criteria and informed consensus. Nuclear receptors related to chemical compounds interactions were selected as biomarkers of effect and their gene expression modulations were analyzed in human peripheral blood mononuclear cell (PBMC). Among couples, subjects not presenting infertility factors (IF--) were separated from affected subjects (IF++). Most IF-- serum samples showed PFOS and PFOA concentrations overlapping the limit of detection (LOD) of 0.5 ng/g wet weight (ww). A substantial percentage of IF++ serum samples showed PFOS concentrations >20-fold the LOD, i.e. from 3 to 50 ng/g ww. In male (50%, n=26) and from 3 to 144 ng/g ww in female (37%, n=30) samples. PFOA values were below the LOD levels in 90% of the total samples. Peroxisome proliferator-activated receptor-gamma (PPARγ) and aryl hydrocarbon receptor (AhR) showed a low level of expression in PBMC of both IF++ and IF-- groups. Whereas alpha and beta estrogen receptors (ERα and ERß), androgen receptor (AR), and pregnane X receptor (PXR) were all upregulated in IF++ of both sexes with respect to IF-- group. Our preliminary results related to the metropolitan area indicate that subjects affected by infertility factors tend to have both higher PFOS levels and higher gene expression of specific nuclear receptors.