The impact of bisphenol A and triclosan on immune parameters in the U.S. population, NHANES 2003-2006

Differences in health symptoms among residents living near illegal dump sites in Los Laureles Canyon, Tijuana, Mexico: a cross sectional survey

Living near landfills is a known health hazard prompting recognition of environmental injustice. The study aim was to compare self-reported symptoms of ill health among residents of four neighborhoods, living in haphazardly constructed settlements surrounded by illegal dumpsites in Tijuana, Mexico. One adult from each of 388 households located in Los Laureles Canyon were interviewed about demographics, health status, and symptoms. Distance from each residence to both the nearest dumpsite and the canyon bottom was assessed. The neighborhoods were selected from locations within the canyon, and varied with respect to proximity to dump sites. Residents of San Bernardo reported significantly higher frequencies of ill-health symptoms than the other neighborhoods, including extreme fatigue (OR 3.01 (95% CI 1.6-5.5)), skin problems/irritations (OR 2.73 (95% CI 1.3-5.9)), stomach discomfort (OR 2.47 (1.3-4.8)), eye irritation/tears (OR 2.02 (1.2-3.6)), and confusion/difficulty concentrating (OR 2.39 (1.2-4.8)). Proximity to dumpsites did not explain these results, that varied only slightly when adjusted for distance to nearest dumpsite or distance to the canyon bottom. Because San Bernardo has no paved roads, we hypothesize that dust and the toxicants it carries is a possible explanation for this difference. Studies are needed to further document this association and sources of toxicants.

Modulation of cytokine expression in human macrophages by endocrine-disrupting chemical Bisphenol-A

Exposure to environmental endocrine-disrupting chemical Bisphenol-A (BPA) is often associated with dysregulated immune homeostasis, but the mechanisms remain unclear. In the present study, the effects of BPA on the cytokines responses of human macrophages were investigated. Treatment with BPA increased pro-inflammation cytokines tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) production, but decreased anti-inflammation cytokines interleukin-10 (IL-10) and transforming growth factor-β (TGF-β) production in THP1 macrophages, as well as in primary human macrophages. BPA effected cytokines expression through estrogen receptor α/β (ERα/β)-dependent mechanism with the evidence of ERα/β antagonist reversed the expression of cytokines. We also identified that activation of extracellular regulated protein kinases (ERK)/nuclear factor κB (NF-κB) signal cascade marked the effects of BPA on cytokines expression. Our results indicated that BPA effected inflammatory responses of macrophages via modulating of cytokines expression, and provided a new insight into the link between exposure to BPA and human health.

Exposure to bisphenol A at physiological concentrations observed in Chinese children promotes primordial follicle growth through the PI3K/Akt pathway in an ovarian culture system

The worldwide increase in the use of bisphenol A (BPA) has resulted in increased human exposure, which could affect human reproductive function. Few studies have investigated the effect of BPA exposure on the primordial follicle pool. In this study, we employed a neonatal ovarian culture system comprising organ obtained from female C57BL/6 pups on postnatal day 4 to assess the effect of BPA on the primordial follicle pool. Ovaries were cultured with BPA (0.1 μM, physiological concentration found in children's blood, and 1 μM, 10 μM) or vehicle for 10 days. Our study revealed that the primary follicle number increased during the early time points (⩽5 days), and we observed a reduction in the primordial follicle pool at a later time point (day 10). This reduction at day 10 was due to increased follicle activation and reduced follicle atresia, as determined by immunohistochemistry for Ki-67 and active caspase-3. Then we examined the phosphatidylinositol-3-kinase (PI3K)/Akt pathway, which is known to be important for early follicle growth. BPA exposure induced the upregulation of the PI3K/Akt pathway, which was reversed by concomitant treatment with PI3K inhibitor. Our results reveal a novel mechanism for BPA-induced primordial follicle activation that involves the PI3K/Akt pathway.

Food intolerance at adulthood after perinatal exposure to the endocrine disruptor bisphenol A

The food contaminant bisphenol A (BPA) is pointed out as a risk factor in development of food allergy and food intolerance, two adverse food reactions increasing worldwide. We evaluated the consequences of perinatal exposure to low doses of BPA on immune-specific response to the food antigen ovalbumin (OVA) at adulthood. Perinatal exposure to BPA (0.5, 5, or 50 μg/kg/d) from 15th day of gravidity to pups weaning resulted in an increase of anti-OVA IgG titers at all BPA dosages in OVA-tolerized rats, and at 5 μg/kg/d in OVA-immunized rats compared to control rats treated with vehicle. In BPA-treated and OVA-tolerized rats, increased anti-OVA IgG titers were associated with higher IFNγ secretion by the spleen. This result is in accordance with the increase of activated CD4(+)CD44(high)CD62L(low) T lymphocytes observed in spleen of BPA-exposed rats compared to controls. Finally, when BPA-treated OVA-tolerized rats were orally challenged with OVA, colonic inflammation occurred, with neutrophil infiltration, increased IFNγ, and decreased TGFβ. We show that perinatal exposure to BPA altered oral tolerance and immunization to dietary antigens (OVA). In summary, the naive immune system of neonate is vulnerable to low doses of BPA that trigger food intolerance later in life.

Health care worker exposures to the antibacterial agent triclosan

OBJECTIVE

We sought to quantify absorption of triclosan, a potential endocrine disruptor, in health care workers with occupational exposure to soap containing this chemical.

METHODS

A cross-sectional convenience sample of two groups of 38 health care workers at separate inpatient medical centers: hospital 1 uses 0.3% triclosan soap in all patient care areas; hospital 2 does not use triclosan-containing products. Additional exposure to triclosan-containing personal care products was assessed through a structured questionnaire. Urine triclosan was quantified and the occupational contribution estimated through regression modeling.

RESULTS

Occupational exposure accounted for an incremental triclosan burden of 206 ng/mL (P = 0.02), while triclosan-containing toothpaste use was associated with 146 ng/mL higher levels (P < 0.001).

CONCLUSIONS

Use of triclosan-containing antibacterial soaps in health care settings represents a substantial and potentially biologically relevant source of occupational triclosan exposure.

Transformation products and human metabolites of triclocarban and triclosan in sewage sludge across the United States

Removal of triclocarban (TCC) and triclosan (TCS) from wastewater is a function of adsorption, abiotic degradation, and microbial mineralization or transformation, reactions that are not currently controlled or optimized in the pollution control infrastructure of standard wastewater treatment. Here, we report on the levels of eight transformation products, human metabolites, and manufacturing byproducts of TCC and TCS in raw and treated sewage sludge. Two sample sets were studied: samples collected once from 14 wastewater treatment plants (WWTPs) representing nine states, and multiple samples collected from one WWTP monitored for 12 months. Time-course analysis of significant mass fluxes (α=0.01) indicate that transformation of TCC (dechlorination) and TCS (methylation) occurred during sewage conveyance and treatment. Strong linear correlations were found between TCC and the human metabolite 2'-hydroxy-TCC (r=0.84), and between the TCC-dechlorination products dichlorocarbanilide (DCC) and monochlorocarbanilide (r=0.99). Mass ratios of DCC-to-TCC and of methyl-triclosan (MeTCS)-to-TCS, serving as indicators of transformation activity, revealed that transformation was widespread under different treatment regimes across the WWTPs sampled, though the degree of transformation varied significantly among study sites (α=0.01). The analysis of sludge sampled before and after different unit operation steps (i.e., anaerobic digestion, sludge heat treatment, and sludge drying) yielded insights into the extent and location of TCC and TCS transformation. Results showed anaerobic digestion to be important for MeTCS transformation (37-74%), whereas its contribution to partial TCC dechlorination was limited (0.4-2.1%). This longitudinal and nationwide survey is the first to report the occurrence of transformation products, human metabolites, and manufacturing byproducts of TCC and TCS in sewage sludge.

Transformation products and human metabolites of triclocarban and triclosan in sewage sludge across the United States

Removal of triclocarban (TCC) and triclosan (TCS) from wastewater is a function of adsorption, abiotic degradation, and microbial mineralization or transformation, reactions that are not currently controlled or optimized in the pollution control infrastructure of standard wastewater treatment. Here, we report on the levels of eight transformation products, human metabolites, and manufacturing byproducts of TCC and TCS in raw and treated sewage sludge. Two sample sets were studied: samples collected once from 14 wastewater treatment plants (WWTPs) representing nine states, and multiple samples collected from one WWTP monitored for 12 months. Time-course analysis of significant mass fluxes (α=0.01) indicate that transformation of TCC (dechlorination) and TCS (methylation) occurred during sewage conveyance and treatment. Strong linear correlations were found between TCC and the human metabolite 2'-hydroxy-TCC (r=0.84), and between the TCC-dechlorination products dichlorocarbanilide (DCC) and monochlorocarbanilide (r=0.99). Mass ratios of DCC-to-TCC and of methyl-triclosan (MeTCS)-to-TCS, serving as indicators of transformation activity, revealed that transformation was widespread under different treatment regimes across the WWTPs sampled, though the degree of transformation varied significantly among study sites (α=0.01). The analysis of sludge sampled before and after different unit operation steps (i.e., anaerobic digestion, sludge heat treatment, and sludge drying) yielded insights into the extent and location of TCC and TCS transformation. Results showed anaerobic digestion to be important for MeTCS transformation (37-74%), whereas its contribution to partial TCC dechlorination was limited (0.4-2.1%). This longitudinal and nationwide survey is the first to report the occurrence of transformation products, human metabolites, and manufacturing byproducts of TCC and TCS in sewage sludge.

Determination of bisphenol A, triclosan and their metabolites in human urine using isotope-dilution liquid chromatography-tandem mass spectrometry

Bisphenol A (BPA) and triclosan (TCS) are ubiquitous environmental phenols exhibiting endocrine disrupting activities that may be involved in various health disorders in humans. There is a need to measure separately free forms and conjugated metabolites because only the former are biologically active. We have developed sensitive methods using isotope-dilution liquid chromatography-tandem mass spectrometry for individual measurements of free BPA and TCS as well as their metabolites, BPA glucuronide (BPAG), BPA monosulfate (BPAS), BPA disulfate (BPADS), TCS glucuronide (TCSG) and TCS sulfate (TCSS) in urine. Comparative analyses of urine samples from 46 volunteers living in the Quebec City area using the new methods and a GC-MS/MS method previously used in our laboratory revealed very strong correlations for total BPA (Spearman's rs=0.862, p<0.0001) and total TCS concentrations (rs=0.942, p<0.0001). Glucuronide metabolites were the most abundant BPA and TCS species in urine samples (>94% of total urinary concentrations). Unconjugated TCS concentrations represented a small proportion of total TCS species (median=1.6%) but its concentration was likely underestimated due to losses by adsorption to the surface of polypropylene tubes used for sample storage. To our knowledge, we are the first to report levels of free, sulfated and glucuronidated TCS levels in human urine.

Relationship between urine dichlorophenol levels and asthma morbidity

BACKGROUND

Chlorinated phenols are associated with atopic conditions, but it is not known whether they are associated with wheeze or asthma and whether atopy is involved in these associations.

OBJECTIVES

To test the association between urine levels of 2 dichlorophenols (2,4- and 2,5-dichlorophenols) and asthma morbidity in atopic and nonatopic wheezers and between total serum immunoglobulin E (IgE) levels.

METHODS

Data from a sample of 2,125 participants at least 6 years old from the US National Health and Nutrition Examination Survey 2005 to 2006 were analyzed. Asthma morbidity data were available for those participants who reported wheezing in the past year ("wheezers"; n = 250). This subsample was categorized as atopic or nonatopic.

RESULTS

Atopic wheezers with higher 2,5-dichlorophenol levels were more frequently diagnosed with asthma by a physician (odds ratio [OR] 4.7 for highest vs lowest tertile, P < .001), required more prescriptions for asthma medications (OR 2.2, P = .046), and reported more exercise-induced wheezing (OR 5.8, P = .045) than atopic wheezers with low dichlorophenol levels. Atopic wheezers with higher 2,5- or 2,4-dichloropheonol levels also were more likely to miss work or school because of wheezing (OR 10.0, P < .001; OR 11.4, P < .01, respectively). In contrast, in nonatopic wheezers, there were no significant associations between dichlorophenol levels and asthma morbidity measurements. The 2 dichlorophenol metabolites were positively associated with increased serum IgE levels in the larger study sample.

CONCLUSION

These findings indicate that in patients with atopy and a history of wheezing, asthma morbidity is associated with high urinary dichlorophenol levels. Increased urine dichlorophenol levels are associated with higher total serum IgE.

On the need and speed of regulating triclosan and triclocarban in the United States

The polychlorinated aromatic antimicrobials triclosan and triclocarban are in widespread use for killing microorganisms indiscriminately, rapidly, and by nonspecific action. While their utility in healthcare settings is undisputed, benefits to users of antimicrobial personal care products are few to none. Yet, these latter, high-volume uses have caused widespread contamination of the environment, wildlife, and human populations. This feature article presents a timeline of scientific evidence and regulatory actions in the U.S. concerning persistent polychlorinated biocides, showing a potential path forward to judicious and sustainable uses of synthetic antimicrobials, including the design of greener and safer next-generation alternatives.

Adverse effects in adulthood resulting from low-level dioxin exposure in juvenile zebrafish

There is strong evidence indicating that disease in adult humans stems from a combination of genetic and environmental factors. A problem in identifying environmental factors is that subacute exposures during early life are often unnoticed, or exposures are variable among a diverse population. This leads to a confusing pattern in adulthood. An additional problem in following exposure effects in humans is the length of time needed to study outcomes spanning a human generation. We have recently developed a zebrafish model for studying the effects of sublethal juvenile exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, dioxin). Although the initial exposure produces no effect at the time, we find skeletal and reproductive defects in adulthood and into subsequent generations. The short generation time of zebrafish along with the ability to maintain large cohorts of exposed individuals and their offspring allows us to overcome variation in exposure and genetic background. Here we describe progress in studying TCDD as an endocrine and developmental disruptor, and our results showing adult consequences of early exposure.

Bisphenol A modulates the metabolic regulator oestrogen-related receptor-α in T-cells

Bisphenol A (BPA) is a widely used plastics constituent that has been associated with endocrine, immune and metabolic effects. Evidence for how BPA exerts significant biological effects at chronic low levels of exposure has remained elusive. In adult men, exposure to BPA has been associated with higher expression of two nuclear receptors, oestrogen receptor-β (ERβ) and oestrogen-related-receptor-α (ERRα), in peripheral white blood cells in vivo. In this study, we explore the expression of ESR2 (ERβ) and ESRRA (ERRα) in human leukaemic T-cell lymphoblasts (Jurkat cells) exposed to BPA in vitro. We show that exposure to BPA led to enhanced expression of ESRRA within 6 h of exposure (mean±s.e.m.: 1.43±0.08-fold increase compared with the control, P<0.05). After 72 h, expression of ESRRA remained significantly enhanced at concentrations of BPA ≥1 nM. Oxidative metabolism of BPA by rat liver S9 fractions yields the potent oestrogenic metabolite, 4-methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene (MBP). Exposure of cells to 1-100 nM MBP increased the expression of both ESRRA (significantly induced, P<0.05, at 1, 10, 100 nM) and ESR2 (1.32±0.07-fold increase at 100 nM exposure, P<0.01). ERRα is a major control point for oxidative metabolism in many cell types, including T-cells. Following exposure to both BPA and MBP, we found that cells showed a decrease in cell proliferation rate. Taken together, these results confirm the bioactivity of BPA against putative T-cell targets in vitro at concentrations relevant to general human exposure.

Bisphenol A and human chronic diseases: current evidences, possible mechanisms, and future perspectives

Bisphenol-A (BPA) is one of the highest volume chemicals produced worldwide, with over 6billion pounds produced and over 100t released into the atmosphere each year. Recent extensive literature has raised concerns about its possible implication in the etiology of some human chronic diseases such as diabetes, obesity, reproductive disorders, cardiovascular diseases, birth defects, chronic respiratory and kidney diseases and breast cancer. In this review, we present the highlighted evidences on the relationship between BPA exposure and human chronic diseases and we discuss its eventual mechanisms of action, especially genetic, epigenetic and endocrine disruption mechanisms with the possible involvement of oxidative stress, mitochondrial dysfunction and cell signaling.

Bisphenol A--sources, toxicity and biotransformation

Bisphenol A (BPA) is a chemical compound used in massive amounts in the production of synthetic polymers and thermal paper. In this review, the sources of BPA, which influence its occurrence in the environment and human surrounding will be presented. Data concerning BPA occurrence in food, water and indoor environments as well as its appearance in tissues and body fluids of human body will be shown. The results of in vitro and in vivo studies and the results of epidemiological surveys showing toxic, endocrine, mutagenic and cancerogenic action of BPA will also be discussed. Moreover, data suggesting that exposure of human to BPA may elevate risk of obesity, diabetes and coronary heart diseases will be presented. Finally, biotransformation of BPA in animals, plants and microorganisms (bacteria, fungi, algae), resulting in the formation of various metabolites that exhibit different from BPA toxicity will be described.

Developmental Immunotoxicity, Perinatal Programming, and Noncommunicable Diseases: Focus on Human Studies

Developmental immunotoxicity (DIT) is a term given to encompass the environmentally induced disruption of normal immune development resulting in adverse outcomes. A myriad of chemical, physical, and psychological factors can all contribute to DIT. As a core component of the developmental origins of adult disease, DIT is interlinked with three important concepts surrounding health risks across a lifetime: (1) the Barker Hypothesis, which connects prenatal development to later-life diseases, (2) the hygiene hypothesis, which connects newborns and infants to risk of later-life diseases and, (3) fetal programming and epigenetic alterations, which may exert effects both in later life and across future generations. This review of DIT considers: (1) the history and context of DIT research, (2) the fundamental features of DIT, (3) the emerging role of DIT in risk of noncommunicable diseases (NCDs) and (4) the range of risk factors that have been investigated through human research. The emphasis on the human DIT-related literature is significant since most prior reviews of DIT have largely focused on animal research and considerations of specific categories of risk factors (e.g., heavy metals). Risk factors considered in this review include air pollution, aluminum, antibiotics, arsenic, bisphenol A, ethanol, lead (Pb), maternal smoking and environmental tobacco smoke, paracetamol (acetaminophen), pesticides, polychlorinated biphenyls, and polyfluorinated compounds.

Human fetal exposure to triclosan and triclocarban in an urban population from Brooklyn, New York

Triclosan (TCS) and triclocarban (TCC) are antimicrobial agents formulated in a wide variety of consumer products (including soaps, toothpaste, medical devices, plastics, and fabrics) that are regulated by the U.S. Food and Drug Administration (FDA) and U.S. Environmental Protection Agency. In late 2014, the FDA will consider regulating the use of both chemicals, which are under scrutiny regarding lack of effectiveness, potential for endocrine disruption, and potential contribution to bacterial resistance to antibiotics. Here, we report on body burdens of TCS and TCC resulting from real-world exposures during pregnancy. Using liquid chromatography tandem mass spectrometry, we determined the concentrations of TCS, TCC, and its human metabolites (2'-hydroxy-TCC and 3'-hydroxy-TCC) as well as the manufacturing byproduct (3'-chloro-TCC) as total concentrations (Σ-) after conjugate hydrolysis in maternal urine and cord blood plasma from a cohort of 181 expecting mother/infant pairs in an urban multiethnic population from Brooklyn, NY recruited in 2007-09. TCS was detected in 100% of urine and 51% of cord blood samples after conjugate hydrolysis. The interquartile range (IQR) of detected TCS concentrations in urine was highly similar to the IQR reported previously for the age-matched population of the National Health and Nutrition Examination Survey (NHANES) from 2003 to 2004, but typically higher than the IQR reported previously for the general population (detection frequency = 74.6%). Urinary levels of TCC are reported here for the first time from real-world exposures during pregnancy, showing a median concentration of 0.21 μg/L. Urinary concentrations of TCC correlated well with its phase-I metabolite ∑-2'-hydroxy-TCC (r = 0.49) and the manufacturing byproduct ∑-3'-chloro-TCC C (r = 0.79), and ∑-2'-hydroxy-TCC correlated strongly with ∑-3'-hydroxy-TCC (r = 0.99). This human biomonitoring study presents the first body burden data for TCC from exposures occurring during pregnancy and provides additional data on composite exposure to TCS (i.e., from both consumer-product use and environmental sources) in the maternal-fetal unit for an urban population in the United States.

Presence and transport of the antimicrobials triclocarban and triclosan in a wastewater-dominated stream and freshwater environment

The presence of the antimicrobials triclocarban (TCC) and triclosan (TCS)in Fountain Creek, a wastewater-dominated stream, and the Arkansas River, Colorado, USA was measured in the surface water, suspended sediments, and bed sediments during spring runoff (high flow) and summer base flow (low flow) conditions. Fountain Creak is a tributary of the Arkansas River. Passive polar organic chemical integrative samplers (POCIS) were used along with active sampling (water grab samples) to measure and TCS concentrations in these surface waters. The concentration of TCC and TCS, based on POCIS measurements, ranged from 4.5 to 47.3 ng/L and 3.9 to 28.3 ng/L, respectively, at the five sample sites monitored in this study under both flow conditions. The range of concentrations of TCC and TCS in suspended sediments was 0.7-57.3 ng/g and 0.7-13.3 ng/g, respectively, and was closely tied to the quantity of organic carbon in the suspended sediment, which ranged from 1.6 to 14.5%. The quantity of organic carbon in suspended sediment during the summer base flow was influenced by runoff from the burn area of a large forest fire that occurred between the two sampling periods. The primary transport mechanism of TCC and TCS in these surface waters was in the dissolved phase, with 64-99% of TCC and 68-99% of TCS transported in the dissolved phase. The total amount of TCS and TCC in bed-sediments was relatively low, with the maximum amount at any one site being 0.38 ± 0.15 ng/g TCS and 4.09 ± 5.26 ng/g TCC. Fountain Creek contributed up to 76% and 69% of the TCC and TCS, respectively, that is transported directly below its confluence with Arkansas River. Fountain Creek drained approximately 3.0 g/day TCS (in spring), 2.9 g/day TCS (in summer) and 1.9 g/day TCC (in spring), 2.0 g/day TCC (in-summer) into the Arkansas River, which suggests consistent input of TCC and TCS into Fountain Creek, such as in discharge of treated wastewater that is independent of changing creek flow conditions.

Transmaternal bisphenol A exposure accelerates diabetes type 1 development in NOD mice

Diabetes mellitus type 1 is an autoimmune disease with a genetic predisposition that is triggered by environmental factors during early life. Epidemiological studies show that bisphenol A (BPA), an endocrine disruptor, has been detected in about 90% of all analyzed human urine samples. In this study, BPA was found to increase the severity of insulitis and the incidence of diabetes in female non obese diabetic (NOD) mice offspring after transmaternal exposure through the dams' drinking water (0, 0.1, 1, and 10mg/l). Both the severity of insulitis in the pancreatic islets at 11 weeks of age and the diabetes prevalence at 20 weeks were significantly increased for female offspring in the highest exposure group compared to the control group. Increased numbers of apoptotic cells, a reduction in tissue resident macrophages and an increase in regulatory T cells were observed in islets prior to insulitis development in transmaternally exposed offspring. The detectable apoptotic cells were identified as mostly glucagon producing alpha-cells but also tissue resident macrophages and beta-cells. In the local (pancreatic) lymph node neither regulatory T cell nor NKT cell populations were affected by maternal BPA exposure. Maternal BPA exposure may have induced systemic immune changes in offspring, as evidenced by alterations in LPS- and ConA-induced cytokine secretion in splenocytes. In conclusion, transmaternal BPA exposure, in utero and through lactation, accelerated the spontaneous diabetes development in NOD mice. This acceleration appeared to be related to early life modulatory effects on the immune system, resulting in adverse effects later in life.

Bisphenol A and human health: a review of the literature

There is growing evidence that bisphenol A (BPA) may adversely affect humans. BPA is an endocrine disruptor that has been shown to be harmful in laboratory animal studies. Until recently, there were relatively few epidemiological studies examining the relationship between BPA and health effects in humans. However, in the last year, the number of these studies has more than doubled. A comprehensive literature search found 91 studies linking BPA to human health; 53 published within the last year. This review outlines this body of literature, showing associations between BPA exposure and adverse perinatal, childhood, and adult health outcomes, including reproductive and developmental effects, metabolic disease, and other health effects. These studies encompass both prenatal and postnatal exposures, and include several study designs and population types. While it is difficult to make causal links with epidemiological studies, the growing human literature correlating environmental BPA exposure to adverse effects in humans, along with laboratory studies in many species including primates, provides increasing support that environmental BPA exposure can be harmful to humans, especially in regards to behavioral and other effects in children.

Perinatal bisphenol A exposures increase production of pro-inflammatory mediators in bone marrow-derived mast cells of adult mice

Bisphenol A (BPA) is a widely used monomer of polycarbonate plastics and epoxide resin that has been implicated in asthma pathogenesis when exposure occurs to the developing fetus. However, few studies have examined the relationship between perinatal BPA exposure and asthma pathogenesis in adulthood. This study used an isogenic mouse model to examine the influence of perinatal BPA exposure via maternal diet on inflammatory mediators associated with asthma in 6-month-old adult offspring by measuring bone marrow-derived mast cell (BMMC) production of lipid mediators (cysteinyl leukotrienes and prostaglandin D2), cytokines (interleukin [IL]-4, IL-5, IL-6, IL-13, and tumor necrosis factor [TNF]-α), and histamine. Global DNA methylation levels in BMMCs from adult offspring were determined to elucidate a potential regulatory mechanism linking perinatal exposure to mast cell phenotype later in life. Four BPA exposure doses were tested: low (50 ng BPA/kg diet, n = 5), medium (50 μg BPA/kg diet, n = 4), high (50 mg BPA/kg diet, n = 4), and control (n = 3). Following BMMC activation, increases in cysteinyl leukotriene (p < 0.01) and TNFα (p < 0.05) production were observed in all BPA-exposure groups, and increases in prostaglandin D2 (p < 0.01) and IL-13 (p < 0.01) production were observed in the high exposure group. Additionally, BMMCs from adult mice in all exposure groups displayed a decrease in global DNA methylation compared to control animals. Thus, perinatal BPA exposure displayed a long-term influence on mast cell-mediated production of pro-inflammatory mediators associated with asthma and global DNA methylation levels, suggesting a potential for mast cell dysregulation, which could affect pulmonary inflammation associated with allergic airway disease into adulthood.

Prenatal and postnatal bisphenol A exposure and asthma development among inner-city children

BACKGROUND

Bisphenol A (BPA) is used widely to manufacture food container linings. Mouse models suggest exposure to BPA might increase allergic inflammation.

OBJECTIVES

We hypothesized that BPA exposure, as assessed based on urinary BPA concentrations, would be associated with increased odds of wheeze and asthma and increased fraction of exhaled nitric oxide (Feno) values in children.

METHODS

The Columbia Center for Children's Environmental Health recruited pregnant women for a prospective birth cohort study (n = 568). Mothers during the third trimester and children at ages 3, 5, and 7 years provided spot urine samples. Total urinary BPA concentrations were measured by using online solid-phase extraction, high-performance liquid chromatography, isotope-dilution tandem mass spectrometry. Wheeze in the last 12 months was measured by using questionnaires at ages 5, 6, and 7 years. Asthma was determined by a physician once between ages 5 and 12 years. Feno values were measured at ages 7 to 11 years.

RESULTS

Prenatal urinary BPA concentrations were associated inversely with wheeze at age 5 years (odds ratio [OR], 0.7; 95% CI, 0.5-0.9; P = .02). Urinary BPA concentrations at age 3 years were associated positively with wheeze at ages 5 years (OR, 1.4; 95% CI, 1.1-1.8; P = .02) and 6 years (OR, 1.4; 95% CI, 1.0-1.9; P = .03). BPA concentrations at age 7 years were associated with wheeze at age 7 years (OR, 1.4; 95% CI, 1.0-1.9; P = .04) and Feno values (β = 0.1; 95% CI, 0.02-0.2; P = .02). BPA concentrations at ages 3, 5, and 7 years were associated with asthma (OR, 1.5 [95% CI, 1.1-2.0], P = .005; OR, 1.4 [95% CI, 1.0-1.9], P = .03; and OR, 1.5 [95% CI, 1.0-2.1], P = .04, respectively).

CONCLUSIONS

This is the first report of an association between postnatal urinary BPA concentrations and asthma in children.

Association of exposure to phenols and idiopathic male infertility

Widespread human exposure to phenols has been documented recently, and some phenols which are potential endocrine disruptors have demonstrated adverse effects on male reproduction in animal and in vitro studies. However, implications about exposure to phenols and male infertility are scarce in humans. Case-control study of 877 idiopathic infertile men and 713 fertile controls was conducted. Urinary levels of bisphenol A, benzophenone-3, pentachlorophenol, triclosan, 4-tert-octylphenol (4-t-OP), 4-n-octylphenol (4-n-OP) and 4-n-nonylphenol (4-n-NP) and semen parameters were measured. After multivariate adjustment, we found 4-t-OP, 4-n-OP and 4-n-NP exposure was associated with idiopathic male infertility (p-value for trend: <0.0001, 0.014 and 0.001, respectively). Aside from these associations, 4-t-OP and 4-n-NP exposure was also associated with idiopathic male infertility with abnormal semen parameters. Moreover, we observed significant associations between sum alkylphenols (APs) exposure and idiopathic male infertility. There were no relationships between exposure to other phenols and idiopathic male infertility in the present study. Our study provides the first evidence that exposure to APs (4-t-OP, 4-n-OP and 4-n-NP) is associated with idiopathic male infertility.

Long-term bisphenol A exposure accelerates insulitis development in diabetes-prone NOD mice

Exposure to the endocrine disruptor (ED) bisphenol A (BPA) used in polycarbonate plastic and epoxy resins appears ubiquitous since BPA can be found in over 90% of analyzed urine samples from all age groups. There is a parallel occurrence of increased prevalence in type 1 diabetes mellitus (T1DM) and an increased exposure to EDs the last decades. T1DM is caused by insulin deficiency due to autoimmune destruction of insulin producing pancreatic beta cells and has been suggested to be induced by various environmental factors acting together with a genetic predisposition. The objective of the present study was to investigate the effect of BPA (0, 1 and 100 mg/l BPA in the drinking water) on T1DM development in nonobese diabetic (NOD) mice, spontaneously developing T1DM. Histological evaluation of pancreas from 12-weeks-old female mice revealed significantly increased insulitis in mice exposed to 1 mg/l BPA, while the insulitis was less severe at the higher BPA exposure. Serum glucose levels in the 1 mg/ml BPA group tended to be hyperglycaemic, also indicating an accelerated onset of T1DM. The high BPA exposure seemed to counteract the diabetes development in females and also in male NOD mice for both BPA concentrations. Prior to insulitis, both BPA concentrations resulted in increased apoptosis and reduced numbers of tissue resident macrophages in pancreatic islets. In conclusion, long-term BPA exposure at a dose three times higher than the tolerable daily intake of 50 µg/kg, appeared to accelerate spontaneous insulitis and diabetes development in NOD mice.

Triclosan exposure and allergic sensitization in Norwegian children

BACKGROUND

Exposure to the synthetic antimicrobial chemical, triclosan, used in personal care products, has been hypothesized to lead to allergic disease. We investigated whether triclosan exposure was associated with allergic sensitization and symptoms in 10-year-old Norwegian children.

METHODS

Urinary concentrations of triclosan were measured in one first morning void from 623 children, collected during 2001-2004. Logistic regression models, controlling for urine specific gravity, parental allergic disease, maternal education, and household income, were fitted for allergic sensitization (either skin prick test positivity or serum-specific IgE ≥ 0.35 kU/l to at least one of 15 evaluated inhalant and food allergens), current rhinitis, and current asthma (questionnaire and exercise challenge test).

RESULTS

The adjusted odds ratio (aOR) for allergic sensitization among those in the fourth quartile of triclosan concentration was 2.0 [95% confidence interval (CI): 1.1, 3.4] compared with the reference group (<the limit of detection), and the aOR per log(10) unit increase in triclosan was 1.2 (95% CI: 1.0, 1.4). The aOR for current rhinitis was 1.9 (95% CI: 1.1, 3.4) for the fourth quartile and 1.2 (95% CI: 0.97, 1.4) per log(10) unit increase in triclosan.

CONCLUSION

Triclosan concentrations were associated with allergic sensitization, especially inhalant and seasonal allergens, rather than food allergens. Current rhinitis was associated with the highest levels of triclosan, whereas no association was seen for current asthma. These results are consistent with recent findings in other studies and provide additional evidence for an association between triclosan and allergy.

Use of NHANES data to link chemical exposures to chronic diseases: a cautionary tale

Background

The National Health and Nutrition Examination Survey (NHANES) is one example of cross-sectional datasets that have been used to draw causal inferences regarding environmental chemical exposures and adverse health outcomes. Our objectives were to analyze four NHANES datasets using consistent a priori selected methods to address the following questions: Is there a consistent association between urinary bisphenol A (BPA) measures and diabetes, coronary heart disease (CHD), and/or heart attack across surveys? Is NHANES an appropriate dataset for investigating associations between chemicals with short physiologic half-lives such as BPA and chronic diseases with multi-factorial etiologies? Data on urinary BPA and health outcomes from 2003–2004, 2005–2006, 2007–2008, and 2009–2010 were available.

Methodology and Findings

Regression models were adjusted for creatinine, age, gender, race/ethnicity, education, income, smoking, heavy drinking, BMI, waist circumference, calorie intake, family history of heart attack, hypertension, sedentary time, and total cholesterol. Urinary BPA was not significantly associated with adverse health outcomes for any of the NHANES surveys, with ORs (95% CIs) ranging from 0.996 (0.951–1.04) to 1.03 (0.978–1.09) for CHD, 0.987 (0.941–1.04) to 1.04 (0.996–1.09) for heart attack, and 0.957 (0.899–1.02) to 1.01 (0.980–1.05) for diabetes.

Conclusions

Using scientifically and clinically supportable exclusion criteria and outcome definitions, we consistently found no associations between urinary BPA and heart disease or diabetes. These results do not support associations and causal inferences reported in previous studies that used different criteria and definitions. We are not drawing conclusions regarding whether BPA is a risk factor for these diseases. We are stating the opposite–that using cross-sectional datasets like NHANES to draw such conclusions about short-lived environmental chemicals and chronic complex diseases is inappropriate. We need to expend resources on appropriately designed epidemiologic studies and toxicological explorations to understand whether these types of chemicals play a causal role in chronic diseases.

Exposure to triclosan augments the allergic response to ovalbumin in a mouse model of asthma

During the last decade, there has been a remarkable and unexplained increase in the prevalence of asthma. These studies were conducted to investigate the role of dermal exposure to triclosan, an endocrine-disrupting compound, on the hypersensitivity response to ovalbumin (OVA) in a murine model of asthma. Triclosan has had widespread use in the general population as an antibacterial and antifungal agent and is commonly found in consumer products such as soaps, deodorants, toothpastes, shaving creams, mouthwashes, and cleaning supplies. For these studies, BALB/c mice were exposed dermally to concentrations of triclosan ranging from 0.75 to 3% (0.375-1.5mg/mouse/day) for 28 consecutive days. Concordantly, mice were ip injected with OVA (0.9 µg) and aluminum hydroxide (0.5mg) on days 1 and 10 and challenged with OVA (125 µg) by pharyngeal aspiration on days 19 and 27. Compared with the animals exposed to OVA alone, increased spleen weights, OVA-specific IgE, interleukin-13 cytokine levels, and numbers of lung eosinophils were demonstrated when mice were coexposed to OVA and triclosan. Statistically significant increases in OVA-specific and nonspecific airway hyperreactivity were observed for all triclosan coexposed groups compared with the vehicle and OVA controls. In these studies, exposure to triclosan alone was not demonstrated to be allergenic; however, coexposure with a known allergen resulted in enhancement of the hypersensitivity response to that allergen, suggesting that triclosan exposure may augment the allergic responses to other environmental allergens.

Urinary levels of bisphenol A, triclosan and 4-nonylphenol in a general Belgian population

Bisphenol A, triclosan and 4-nonylphenol are among the endocrine disruptors which are widely used in daily products. In this study, we reported total urinary levels of bisphenol A, triclosan and 4-nonylphenol, in order to evaluate the baseline contamination of a general population in Belgium. Bisphenol A and triclosan were detected in respectively 97.7% and 74.6% of the samples examined demonstrating that the general Belgian population is extensively exposed to both chemicals. On the other hand, 4-nonylphenol was not detected in any urine samples analyzed, suggesting either low exposure, inadequate biomarker, or that urine is an inappropriate biological matrix for assessing exposure to nonylphenol commercial mixtures. Geometric mean concentration was determined for bisphenol A at 2.55 μg/l and for triclosan at 2.70 μg/l. No significant difference was observed between levels and gender for both bisphenol A and triclosan. When classified by age, the 20-39 year group showed the highest triclosan levels, while all age groups seemed to be similarly exposed to bisphenol A. Both bisphenol A and triclosan urinary levels were not correlated with creatinine excretion in our healthy population, questioning the relevance of the creatinine adjustment in reporting these chemical levels. Bisphenol A levels in urine of people living in the same home and collected on the same time were fairly correlated, confirming the assumption that dietary intake would be the primary route of exposure. Triclosan urinary levels were not correlated with bisphenol A levels.

New bactericidal surgical suture coating

This paper demonstrates the effectiveness of a new antimicrobial suture coating. An amphiphilic polymer, poly[(aminoethyl methacrylate)-co-(butyl methacrylate)] (PAMBM), inspired by antimicrobial peptides, was bactericidal against S. aureus in time-kill experiments. PAMBM was then evaluated in a variety of polymer blends using the Japanese Industrial Standard (JIS) method and showed excellent antimicrobial activity at a low concentration (0.5 wt %). Using a similar antimicrobial coating formula to commercial Vicryl Plus sutures, disk samples of the coating material containing PAMBM effectively killed bacteria (98% reduction at 0.75 wt %). Triclosan, the active ingredient in Vicryl Plus coatings, did not kill the bacteria. Further Kirby-Bauer assays of these disk samples showed an increasing zone of inhibition with increasing concentration of PAMBM. Finally, the PAMBM-containing coating was applied to sutures, and the morphology of the coating surface was characterized by SEM, along with Vicryl and uncoated sutures. The PAMBM-containing sutures killed bacteria more effectively (3 log(10) reduction at 2.4 wt %) than Vicryl Plus sutures (0.5 log(10) reduction).

Triclosan impairs excitation-contraction coupling and Ca2+ dynamics in striated muscle

Triclosan (TCS), a high-production-volume chemical used as a bactericide in personal care products, is a priority pollutant of growing concern to human and environmental health. TCS is capable of altering the activity of type 1 ryanodine receptor (RyR1), but its potential to influence physiological excitation-contraction coupling (ECC) and muscle function has not been investigated. Here, we report that TCS impairs ECC of both cardiac and skeletal muscle in vitro and in vivo. TCS acutely depresses hemodynamics and grip strength in mice at doses ≥12.5 mg/kg i.p., and a concentration ≥0.52 μM in water compromises swimming performance in larval fathead minnow. In isolated ventricular cardiomyocytes, skeletal myotubes, and adult flexor digitorum brevis fibers TCS depresses electrically evoked ECC within ∼10-20 min. In myotubes, nanomolar to low micromolar TCS initially potentiates electrically evoked Ca(2+) transients followed by complete failure of ECC, independent of Ca(2+) store depletion or block of RyR1 channels. TCS also completely blocks excitation-coupled Ca(2+) entry. Voltage clamp experiments showed that TCS partially inhibits L-type Ca(2+) currents of cardiac and skeletal muscle, and [(3)H]PN200 binding to skeletal membranes is noncompetitively inhibited by TCS in the same concentration range that enhances [(3)H]ryanodine binding. TCS potently impairs orthograde and retrograde signaling between L-type Ca(2+) and RyR channels in skeletal muscle, and L-type Ca(2+) entry in cardiac muscle, revealing a mechanism by which TCS weakens cardiac and skeletal muscle contractility in a manner that may negatively impact muscle health, especially in susceptible populations.

The effects of maternal exposure to bisphenol A on allergic lung inflammation into adulthood

Bisphenol A (BPA) is a high-production volume chemical classified as an environmental estrogen and used primarily in the plastics industry. BPA's increased usage correlates with rising BPA levels in people and a corresponding increase in the incidence of asthma. Due to limited studies, the contribution of maternal BPA exposure to allergic asthma pathogenesis is unclear. Using two established mouse models of allergic asthma, we examined whether developmental exposure to BPA alters hallmarks of allergic lung inflammation in adult offspring. Pregnant C57BL/6 dams were gavaged with 0, 0.5, 5, 50, or 500 μg BPA/kg/day from gestational day 6 until postnatal day 21. To induce allergic inflammation, adult offspring were mucosally sensitized with inhaled ovalbumin containing low-dose lipopolysaccharide or ip sensitized using ovalbumin with alum followed by ovalbumin aerosol challenge. In the mucosal sensitization model, female offspring that were maternally exposed to ≥ 50 μg BPA/kg/day displayed enhanced airway lymphocytic and lung inflammation, compared with offspring of control dams. Peritoneally sensitized, female offspring exposed to ≤ 50 μg BPA/kg/day presented dampened lung eosinophilia, compared with vehicle controls. Male offspring did not exhibit these differences in either sensitization model. Our data demonstrate that maternal exposure to BPA has subtle and qualitatively different effects on allergic inflammation, which are critically dependent upon route of allergen sensitization and sex. However, these subtle, yet persistent changes due to developmental exposure to BPA did not lead to significant differences in overall airway responsiveness, suggesting that early life exposure to BPA does not exacerbate allergic inflammation into adulthood.

A novel resistance mechanism to triclosan that suggests horizontal gene transfer and demonstrates a potential selective pressure for reduced biocide susceptibility in clinical strains of Staphylococcus aureus

The widely used biocide triclosan selectively targets FabI, the NADH-dependent trans-2-enoyl-acyl carrier protein reductase, which is an important target for narrow-spectrum antimicrobial drug development. In relation to the growing concern about biocide resistance, we compared in vitro mutants and clinical isolates of Staphylococcus aureus with reduced triclosan susceptibility. Clinical isolates of S. aureus as well as laboratory-generated mutants were assayed for minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) phenotypes and genotypes related to reduced triclosan susceptibility. A potential epidemiological cut-off (ECOFF) MBC of >4 mg/L was observed for triclosan in clinical isolates of S. aureus. These showed significantly lower MICs and higher MBCs than laboratory mutants. These groups of strains also had few similarities in the triclosan resistance mechanism. Molecular analysis identified novel resistance mechanisms linked to the presence of an additional sh-fabI allele derived from Staphylococcus haemolyticus. The lack of predictive value of in-vitro-selected mutations for clinical isolates indicates that laboratory tests in the present form appear to be of limited value. More importantly, detection of sh-fabI as a novel resistance mechanism with high potential for horizontal gene transfer demonstrates for the first time that a biocide could exert a selective pressure able to drive the spread of a resistance determinant in a human pathogen.

Immunomodulatory effects of environmental endocrine disrupting chemicals

During recent decades more than 100,000 new chemicals have been introduced as common consumer products into our environment. Among these chemicals, endocrine-disrupting chemicals (EDCs) are of particular concern owing to their toxicity in animal studies and their impacts on human health. EDCs are ubiquitous in the environment, including the air, water, and soil. The endocrine-disrupting effect of EDCs has been found to imitate the action of steroid hormones and promote several endocrine and reproductive disorders in both animal and human studies. In the present review, we focus on the effects of EDCs on the immune system. EDCs interfere with the synthesis of cytokines, immunoglobulins, and inflammatory mediators, and they also affect the activation and survival of immune cells. The dysfunction of the immune system caused by EDCs may lead to the attenuation of immunity (immunodeficiency) against infection or hyperreactivity of immune responses (allergy and autoimmune disease). In this review, we summarize epidemiologic, animal, and cell studies to demonstrate the potential effects of EDCs on immunity, allergy, and autoimmune diseases. We also address the impact of EDCs on epigenetic regulation.

Urinary levels of triclosan and parabens are associated with aeroallergen and food sensitization

BACKGROUND

Endocrine-disrupting compounds (EDCs) have immune-modulating effects. We were interested in determining their association with allergic sensitization.

OBJECTIVE

We sought to determine the association between EDCs and allergic sensitization and whether this relationship depends on the antimicrobial properties of the EDCs, sex, or both.

METHODS

Data were obtained from the 2005-2006 National Health and Nutrition Examination Survey in which urinary bisphenol A; triclosan; benzophenone-3; propyl, methyl, butyl, and ethyl parabens; and specific IgE levels were available for 860 children. Aeroallergen and food sensitizations were defined as having at least 1 positive (≥ 0.35 kU/L) specific IgE level to an aeroallergen or a food. Logistic regression was used to determine the association of EDCs and sensitization. Analyses were adjusted for urinary creatinine level, age, sex, ethnicity, and poverty index ratio.

RESULTS

The odds of aeroallergen sensitization significantly increased with the level of the antimicrobial EDCs triclosan and propyl and butyl parabens (P ≤ .04). The odds of food sensitization significantly increased with the level of urinary triclosan among male subjects (odds ratio for third vs first tertiles, 3.9; P= .02 for trend). There was a significant interaction between sex and triclosan level, with male subjects being more likely to be food sensitized with exposure (P= .03). Similar associations were not identified for the nonantimicrobial EDCs bisphenol A and benzophenone-3 (P > .2).

CONCLUSIONS

As a group, EDCs are not associated with allergen sensitization. However, levels of the antimicrobial EDCs triclosan and parabens were significantly associated with allergic sensitization. The potential role of antimicrobial EDCs in allergic disease warrants further study because they are commonly used in Western society.

Developmental exposure to bisphenol A modulates innate but not adaptive immune responses to influenza A virus infection

Bisphenol A (BPA) is used in numerous products, such as plastic bottles and food containers, from which it frequently leaches out and is consumed by humans. There is a growing public concern that BPA exposure may pose a significant threat to human health. Moreover, due to the widespread and constant nature of BPA exposure, not only adults but fetuses and neonates are also exposed to BPA. There is mounting evidence that developmental exposures to chemicals from our environment, including BPA, contribute to diseases late in life; yet, studies of how early life exposures specifically alter the immune system are limited. Herein we report an examination of how maternal exposure to a low, environmentally relevant dose of BPA affects the immune response to infection with influenza A virus. We exposed female mice during pregnancy and through lactation to the oral reference dose for BPA listed by the US Environmental Protection Agency, and comprehensively examined immune parameters directly linked to disease outcomes in adult offspring following infection with influenza A virus. We found that developmental exposure to BPA did not compromise disease-specific adaptive immunity against virus infection, or reduce the host's ability to clear the virus from the infected lung. However, maternal exposure to BPA transiently reduced the extent of infection-associated pulmonary inflammation and anti-viral gene expression in lung tissue. From these observations, we conclude that maternal exposure to BPA slightly modulates innate immunity in adult offspring, but does not impair the anti-viral adaptive immune response, which is critical for virus clearance and survival following influenza virus infection.

Environmentally induced epigenetic transgenerational inheritance of ovarian disease

The actions of environmental toxicants and relevant mixtures in promoting the epigenetic transgenerational inheritance of ovarian disease was investigated with the use of a fungicide, a pesticide mixture, a plastic mixture, dioxin and a hydrocarbon mixture. After transient exposure of an F0 gestating female rat during embryonic gonadal sex determination, the F1 and F3 generation progeny adult onset ovarian disease was assessed. Transgenerational disease phenotypes observed included an increase in cysts resembling human polycystic ovarian disease (PCO) and a decrease in the ovarian primordial follicle pool size resembling primary ovarian insufficiency (POI). The F3 generation granulosa cells were isolated and found to have a transgenerational effect on the transcriptome and epigenome (differential DNA methylation). Epigenetic biomarkers for environmental exposure and associated gene networks were identified. Epigenetic transgenerational inheritance of ovarian disease states was induced by all the different classes of environmental compounds, suggesting a role of environmental epigenetics in ovarian disease etiology.

Triclosan, an antibacterial agent, increases intracellular Zn(2+) concentration in rat thymocytes: its relation to oxidative stress

Triclosan is used as an antibacterial agent in household items and personal care products. Since this compound is found in maternal milk of humans and bodies of wild animals, there is growing concern among some consumer groups and scientific community that triclosan is adverse for humans and wild animals. In order to estimate adverse actions of triclosan, the effects of triclosan on intracellular Zn(2+) concentration and cellular thiol content were studied in rat thymocytes by the use of flow cytometer with appropriate fluorescent probes. Triclosan at 1-3 μM (sublethal concentrations) increased the intensity of FluoZin-3 fluorescence (intracellular Zn(2+) concentration) and decreased the intensity of 5-chloromethylfluorescein (5-CMF) fluorescence (cellular thiol content). Negative correlation (r=-0.985) between triclosan-induced changes in FluoZin-3 and 5-CMF fluorescences was found. Removal of external Zn(2+) did not significantly affect the triclosan-induced augmentation of FluoZin-3 fluorescence, suggesting an intracellular Zn(2+) release by triclosan. These actions of triclosan were similar to those of H(2)O(2) and triclosan significantly potentiated the cytotoxicity of H(2)O(2). Therefore, the results may suggest that triclosan at sublethal concentrations induces oxidative stress that decreases cellular thiol content, resulting in an increase in intracellular Zn(2+) concentration by Zn(2+) release from intracellular store(s). Since recent studies show many physiological roles of intracellular Zn(2+) in cellular functions, the triclosan-induced disturbance of cellular Zn(2+) homeostasis may induce adverse actions on the cells.

Bisphenol A and phthalates exhibit similar toxicogenomics and health effects

Plastics are widely used in modern life, and their unbound chemicals bisphenol A and phthalates can leach out into the surrounding environment. BPA and PAEs have recently attracted the special attention of the scientific community, regulatory agencies and the general public because of their high production volume, widespread use of plastics, and endocrine-disrupting effects. In The Comparative Toxicogenomics Database, BPA and five most frequently curated PAEs (DEHP/MEHP and DBP/BBP/MBP) were found to have 1932 and 484 interactions with genes/proteins, respectively. Five of their top ten toxicity networks were found to be involved in inflammation, and their top ten diseases included genital, prostatic, endomentrial, ovarian and breast diseases. BPA and PAEs were found to exhibit similar toxicogenomics and adverse effects on human health owning to their 89 common interacting genes/proteins. These 89 genes/proteins may serve as biomarkers to assay the toxicities of different chemicals leached out from the widely used plastics.

Urinary concentrations of bisphenol A and triclosan and associations with demographic factors in the Korean population

Bisphenol A (BPA) and triclosan are synthetic phenolic compounds to which the general public can be extensively exposed via consumer products and environmental contamination. In this study, we assessed exposure to BPA and triclosan in the Korean adult population aged 18-69 based on the Korean National Human Biomonitoring Survey conducted in 2009. Relying on data from 1870 representative Koreans, we found that the geometric mean urinary concentrations of BPA and triclosan were 1.90 ng/ml [95% confidence interval (CI): 1.81-1.99] and 1.68 ng/ml (95% CI: 1.48-1.90), respectively. The creatinine-adjusted geometric means of BPA and triclosan were 1.79 μg/g creatinine (95% CI: 1.70-1.90) and 1.58 μg/g creatinine (95% CI: 1.39-1.81), respectively. About 99.8% of the Korean adult population had urinary concentrations of BPA and about 92.6% of the Korean adult population had urinary concentrations of triclosan above the level of 0.05 ng/ml (limit of detection, LOD). Urinary BPA concentrations were higher in residents of rural areas, whereas urinary triclosan concentrations were significantly associated with cigarette smoking. These findings suggested that most Koreans had detectable levels of BPA and triclosan in their urine and that the body burden of BPA and triclosan varied according to demographic and geographic factors.

Triclosan, an environmental pollutant from health care products, evokes charybdotoxin-sensitive hyperpolarization in rat thymocytes

The effects of triclosan, an environmental pollutant from household items and health care products, on membrane potential and intracellular Ca(2+) concentrations of rat thymocytes were examined by a flow cytometry with fluorescent probes, di-BA-C(4) and fluo-3-AM, because triclosan is often found in humans and wild animals. Triclosan at a concentration of 3 μM decreased the intensity of di-BA-C(4) fluorescence, indicating the triclosan-induced hyperpolarization. The application of charybdotoxin, a specific inhibitor of Ca(2+)-dependent K(+) channels, and the removal of external Ca(2+) eliminated the triclosan-attenuation of di-BA-C(4) fluorescence. Furthermore, triclosan augmented the fluo-3 fluorescence under normal Ca(2+) condition, indicating that triclosan increased intracellular Ca(2+) concentration. These results suggest that triclosan induces membrane hyperpolarization by increasing intracellular Ca(2+) concentration that activates Ca(2+)-dependent K(+) channels. Since the change in membrane potential of lymphocytes influence cellular immune functions, triclosan may exert adverse actions on immune system in human and wild animals.

Recent trends in biomonitoring of bisphenol A, 4-t-octylphenol, and 4-nonylphenol

Bisphenol A (BPA), 4-t-octylphenol (4-t-OP), and 4-nonylphenol (4-NP) are man-made alkylphenolic environmental contaminants possessing controversial endocrine disruption properties. Nowadays, an increased interest is raised for their accurate determination in biological media in order to estimate the exposure to these compounds and the associated health risk. The aim of this review is to present the available analytical methodologies for biomonitoring these three EDCs in human population. In non-occupational human exposure, they are detected in human matrices in trace level concentrations, commonly lower than 1ng/mL. The use of mass spectrometry based methods is particularly emphasized due to their well known superiority over sensitivity, selectivity and precision, even in difficult matrices, such as blood plasma and serum. Recent and most applicable sample preparation techniques are thoroughly presented. The benefits of solid phase extraction (SPE) and expected developments are demonstrated. Recent results from exposure assessment and epidemiologic studies for BPA, 4-t-OP and 4-NP are summarized and future trends are discussed.

Epigenetic perspective on the developmental effects of bisphenol A

Bisphenol A (BPA) is an estrogenic environmental toxin widely used in the production of plastics and ubiquitous human exposure to this chemical has been proposed to be a potential risk to public health. Animal studies suggest that in utero and early postnatal exposure to this compound may produce a broad range of adverse effects, including impaired brain development, sexual differentiation, behavior, and immune function, which could extend to future generations. Molecular mechanisms that underlie the long-lasting effects of BPA continue to be elucidated, and likely involve disruption of epigenetic programming of gene expression during development. Several studies have provided evidence that maternal exposure to BPA results in postnatal changes in DNA methylation status and altered expression of specific genes in offspring. However, further studies are needed to extend these initial findings to other genes in different tissues, and to examine the correlations between BPA-induced epigenetic alterations, changes in gene expression, and various phenotypic outcomes. It will be also important to explore whether the epigenetic effects of BPA are related to its estrogenic activity, and to determine which downstream effector proteins could mediate changes in DNA methylation. In this review, we will highlight research indicating a consequence of prenatal BPA exposure for brain, behavior, and immune outcomes and discuss evidence for the role of epigenetic pathways in shaping these developmental effects. Based on this evidence, we will suggest future directions in the study of BPA-induced epigenetic effects and discuss the transgenerational implications of exposure to endocrine disrupting chemicals.