Combined Toxic Effects of BPA and Its Two Analogues BPAP and BPC in a 3D HepG2 Cell Model.

Bisphenol A (BPA) is one of the most commonly used substances in the manufacture of various everyday products. Growing concerns about its hazardous properties, including endocrine disruption and genotoxicity, have led to its gradual replacement by presumably safer analogues in manufacturing plastics. The widespread use of BPA and, more recently, its analogues has increased their residues in the environment. However, our knowledge of their toxicological profiles is limited and their combined effects are unknown. In the present study, we investigated the toxic effects caused by single bisphenols and by the combined exposure of BPA and its two analogues, BPAP and BPC, after short (24-h) and prolonged (96-h) exposure in HepG2 spheroids. The results showed that BPA did not reduce cell viability in HepG2 spheroids after 24-h exposure. In contrast, BPAP and BPC affected cell viability in HepG2 spheroids. Both binary mixtures (BPA/BPAP and BPA/BPC) decreased cell viability in a dose-dependent manner, but the significant difference was only observed for the combination of BPA/BPC (both at 40 µM). After 96-h exposure, none of the BPs studied affected cell viability in HepG2 spheroids. Only the combination of BPA/BPAP decreased cell viability in a dose-dependent manner that was significant for the combination of 4 µM BPA and 4 µM BPAP. None of the BPs and their binary mixtures studied affected the surface area and growth of spheroids as measured by planimetry. In addition, all BPs and their binary mixtures studied triggered oxidative stress, as measured by the production of reactive oxygen species and malondialdehyde, at both exposure times. Overall, the results suggest that it is important to study the effects of BPs as single compounds. It is even more important to study the effects of combined exposures, as the combined effects may differ from those induced by single compounds.

Quantitative in vitro-to-in vivo extrapolation (QIVIVE) of estrogenic and anti-androgenic potencies of BPA and BADGE analogues.

The goal of the present study was to obtain an in vivo relevant prioritization method for the endocrine potencies of different polycarbonate monomers, by combining in vitro bioassay data with physiologically based kinetic (PBK) modelling. PBK models were developed for a selection of monomers, including bisphenol A (BPA), two bisphenol F (BPF) isomers and four different bisphenol A diglycidyl ethers (BADGEs), using in vitro input data. With these models, the plasma concentrations of the compounds were simulated, providing means to estimate the dose levels at which the in vitro endocrine effect concentrations are reached. The results revealed that, whereas the in vitro relative potencies of different BADGEs (predominantly anti-androgenic effects) can be up to fourfold higher than BPA, the estimated in vivo potencies based on the oral equivalent doses are one to two orders of magnitude lower than BPA because of fast detoxification of the BADGEs. In contrast, the relative potencies of 2,2-BPF and 4,4-BPF increase when accounting for the in vivo availability. 4,4-BPF is estimated to be fivefold more potent than BPA in humans in vivo in inducing estrogenic effects and both 2,2-BPF and 4,4-BPF are estimated to be, respectively, 7 and 11-fold more potent in inducing anti-androgenic effects. These relative potencies were considered to be first-tier estimates, particularly given that the potential influence of intestinal metabolism on the in vivo availability was not accounted for. Overall, it can be concluded that both 2,2-BPF and 4,4-BPF are priority compounds.

BPA, BADGE and analogues: A new multi-analyte LC-ESI-MS/MS method for their determination and their in vitro (anti)estrogenic and (anti)androgenic properties.

Information on the occurrence and endocrine potencies of analogues of bisphenol A (BPA) and diglycidyl ester derivatives (BDGEs) of BPA and BPF is limited. Such information is, however, important as the current debate on BPA and the lowered BPA migration limit in Europe may provide an incentive for application of structural analogues. A new sensitive multi-analyte LC-ESI-MS/MS method was developed to measure 17 bisphenols (BPs) and 6 BDGEs in food, beverages and drinkware. Yeast based bioassays were used to determine the in vitro (anti)estrogenic and (anti)androgenic properties of these and 7 additional BPs and BDGEs. Drinkware of polycarbonate and other materials were analysed for BPs and BDGEs. Only BPA and BPS and both at trace levels were found in a few containers. A limited number of (canned) foods and beverages were also analysed. BPA was the most frequently detected BP (ranged from 0.03 ng mL-1 in a beverage sample to 68 ng g-1 in food). Other BPs detected were BPS, 2,2-BPF and 4,4-BPF. In addition BADGE, BADGE.HCl, BADGE.H2O and BADGE.2H2O were detected from 0.08 ng mL-1 in a beverage sample to 3.3 ng g-1 in food. In vitro testing showed that most BPs exhibited an equal or higher estrogenic potency than BPA and most of them also showed a higher anti-androgenic potency, i.e. BPB, BPCl, BPC, BPE, 4,4-BPF, BPP, BPAF, and BPTMC. Some BPs and BDGEs were not estrogenic, but showed an anti-estrogenic effect and were anti-androgenic too. BPS was only weakly estrogenic and BADGE.2H2O and BFDGE.2H2O showed no in vitro activity. The present data show that in addition to BPA, other BPs and BDGEs can be present in food and drinks, some displaying in vitro endocrine activities.