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Employing Dietary Comparators to Perform Risk Assessments for Anti-Androgens Without Using Animal Data.

ABSTRACT: This study investigated the use of androgen receptor (AR) reporter gene assay data in a non-animal exposure-led risk assessment in which in vitro anti-androgenic activity and exposure data were put into context using a naturally occurring comparator substance with a history of dietary consumption. First, several dietary components were screened to identify which selectively interfered with AR signaling in vitro, using the AR CALUX® test. The IC50 values from these dose-response data together with measured or predicted human exposure levels were used to calculate exposure: activity ratios (EARs) for the dietary components and a number of other well-known anti-androgenic substances. Both diindolylmethane (DIM) and resveratrol are specifically acting dietary anti-androgens. The EARs for several anti-androgens were therefore expressed relative to the EAR of DIM, and how this 'dietary comparator ratio' (DCR) approach may be used to make safety decisions was assessed using an exposure-led case study for an anti-androgenic botanical ingredient. This highlights a pragmatic approach which allows novel chemical exposures to be put into context against dietary exposures to natural anti-androgenic substances. The DCR approach may have utility for other modes of action where appropriate comparators can be identified.

SUBMITTER: Dent MP

PROVIDER: S-EPMC6358230 | biostudies-literature | 2019 Feb

REPOSITORIES: biostudies-literature

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Employing Dietary Comparators to Perform Risk Assessments for Anti-Androgens Without Using Animal Data.

Dent Matthew P MP Li Hequn H Carmichael Paul L PL Martin Francis L FL

Toxicological sciences : an official journal of the Society of Toxicology 20190201 2

This study investigated the use of androgen receptor (AR) reporter gene assay data in a non-animal exposure-led risk assessment in which in vitro anti-androgenic activity and exposure data were put into context using a naturally occurring comparator substance with a history of dietary consumption. First, several dietary components were screened to identify which selectively interfered with AR signaling in vitro, using the AR CALUX® test. The IC50 values from these dose-response data together wit ...[more]

PMID: 30247711

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Project description:Study questionWhat are the changes in serum concentration of total and cleaved anti-Muüllerian hormone (AMH) molecular forms and of androgens before and throughout pregnancy in women with and without polycystic ovary syndrome (PCOS) in a longitudinal follow-up investigation?Summary answerSerum levels of total and cleaved AMH are higher from preconception to the third trimester of pregnancy in women with PCOS as compared to controls, whereas testosterone and androstenedione levels are higher in women with PCOS than in control women before pregnancy and during the second and third trimester of pregnancy.What is known alreadyCross-sectional or partial longitudinal studies have shown higher AMH and androgen levels in pregnant women with PCOS as compared with non-PCOS women. To date, no complete longitudinal dynamic monitoring of the circulating forms of AMH and androgens from pre-conception to the third trimester of pregnancy have compared women with and without PCOS.Study design, size, durationThis systematic prospective quarterly longitudinal monocentric study was a comparative follow-up of 30 women with PCOS and 29 controls before and during pregnancy from April 2019 to July 2022.Participants/materials, setting, methodsWomen aged 18-43 years with a pre-conception measurement of AMH were included during the first trimester of a singleton pregnancy. The PCOS group was defined according to the Rotterdam diagnostic criteria. The control group patients included in the study had normal ovarian reserves. Circulating total and cleaved AMH, and serum estradiol, LH, and androgen levels were measured during the first, second, and third trimester of pregnancy in all study participants.Main results and the role of chanceBefore pregnancy, patients with PCOS had higher levels of AMH than controls. The total and cleaved AMH forms were significantly higher in women with PCOS than controls from pre-conception to the third trimester of pregnancy (all P < 0.001). Androgens (total testosterone and androstenedione) were higher in women with PCOS than controls from mid-pregnancy onwards.Limitations, reasons for cautionOur control population was a population of infertile women with no ovarian problems but most of them had undergone ART treatments to achieve pregnancy.Wider implications of the findingsThese results strengthen the hypothesis that gestational hyperandrogenism as well as exposure to elevated AMH levels in utero could be driving forces predisposing female progeny to develop PCOS.Study funding/competing interest(s)Funding was provided by INSERM, France (grant number U1172) and the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program, ERC-2016-CoG to P.G. grant agreement n° 725149/REPRODAMH. The authors have nothing to declare.Trial registration numberNCT03483792.

Project description:Biochar is the degradation-resistant product generated by the pyrolysis of organic materials and is produced for the intended use of land application in order to promote carbon sequestration and soil improvement. However, despite the many potential benefits biochar application offers, it is important to quantify any ecological impacts that may result from soil amendment in order to avoid potentially causing negative effects upon soil biota which are crucial in the many ecosystem services provided by soil. Any impacts on earthworms in particular are important to evaluate because of their pivotal role in organic matter breakdown, nutrient cycling and soil formation. In this study, we conducted a series of ecotoxicological assays to determine lethal and sublethal (avoidance, mass change and moisture content) effects of heavy biochar applications that reflect levels that may be used in soil restoration efforts. Two earthworm species, Eisenia fetida, an epigeic species, and Lumbricus terrestris, an anecic species, were utilised as test organisms. Two types of biochar, produced from wheat straw and rice husk feedstocks, respectively, were applied to OECD artificial soil and to a natural soil (Kettering loam) at rates of up to 20% w/w. The influence of biochar application on soil porewater chloride, fluoride and phosphate concentrations was also assessed. The biochar applications induced only a subtle level of avoidance behaviour while effects on survival over a 4-week exposure period were inconsistent. However, death and physical damage to some individual earthworms at high biochar application rates were observed, the mechanisms and processes leading to which should be investigated further. Earthworm development (mean mass change over time) proved to be a more sensitive measure, revealing negative effects on L. terrestris at 10% and 20% (w/w) wheat biochar applications in OECD soil and at 20% (w/w) applications of both biochars in Kettering loam. The moisture content of E. fetida remained remarkably consistent across all treatments (~ 82%), indicating that this is not a sensitive measure of effects. The high rates of biochar application resulted in increased chloride (2 to 3-fold) and phosphate (100-fold) concentrations in simulated soil porewaters, which has important implications for soil fertility and production but also for environmental management.

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Employing Dietary Comparators to Perform Risk Assessments for Anti-Androgens Without Using Animal Data.

Publications

Employing Dietary Comparators to Perform Risk Assessments for Anti-Androgens Without Using Animal Data.

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