Identification of a xenobiotic as a potential environmental trigger in primary biliary cholangitis

Impact of emerging pollutants mixtures on marine and brackish phytoplankton: diatom Phaeodactylum tricornutum and cyanobacterium Microcystis aeruginosa

Pharmaceuticals and ionic liquids (ILs) are emerging as significant micropollutants with environmental presence and potential ecological impacts. The possible simultaneous occurrence of these two groups of pollutants in aquatic environments raises complex challenges due to their diverse chemical properties and potential for interactive effects. Given the documented widespread presence of pharmaceuticals and the emerging concerns about ILs, the study aims to evaluate the adverse effects of binary mixtures of imidazolium ionic liquid IM1-8C(CN)3 and two representatives of pharmaceuticals: antibiotic oxytetracycline (OXTC) and metabolite carbamazepine 10,11 epoxide (CBZ-E) on the brackish cyanobacterium Microcystis aeruginosa and the marine diatom Phaeodactylum tricornutum during chronic exposure experiments. A comprehensive approach was employed, incorporating various endpoints including oxidative stress, chlorophyll a fluorescence, detailed photoprotective and photosynthetic pigment profiles of target microorganisms to assess modes of action and identify the mixture effects of the selected substances. The observed alterations in pigment production affecting carotenoids synthesis in both selected species may be attributed to the differential impacts of these substances on the photosynthetic pathways and metabolic processes in the cyanobacterial and diatom cells. Changes in chlorophyll a fluorescence-specific parameters suggest impairment of the photosynthetic activity, particularly affecting the efficiency of photosystem II. The application of Concentration Addition (CA) and Independent Action (IA) mathematical models, complemented by the evaluation of Model Deviation Ratios (MDR), revealed predominantly antagonistic interactions within the studied mixtures. The findings of this study provide important insights into the effects of mixtures of organic micropollutants and their potential impact on environment including brackish and marine waters.

Development and validation of diffusive gradients in thin-films for in situ monitoring of ionic liquids in waters

Due to their wide applications, occurrence and "PFAS-like" environmental behaviors, ionic liquids (ILs) represent a new challenge for the environmental monitoring community, who require robust analytical methods that can determine accurately and efficiently their environmentally relevant concentrations. A new passive sampling method based on the diffusive gradients in thin films (DGT) technique was developed for the measurement of imidazole-based ILs in waters using a mixed-mode cation exchange (MCX) resin as the adsorbent. The selected binding gel had a high binding capacity (>170 μg per disc) for ILs. Diffusion coefficients measured using a diffusion cell correlated well with alkyl chain lengths (r2 = 0.95) and retention times (r2 = 0.88), providing a simple and rapid prediction approach for other ILs. The assembled MCX-DGT sampler exhibited a linear accumulation for at least 120 h. MCX-DGT also showed good performance under typical freshwater conditions (pH 5-8, ionic strength 0.001-0.01 M, and humic acid 0-5 mg L-1), while still being problematic for aquatic conditions with higher ionic strength (>0.1 M) or DOM (>10 mg L-1). Laboratory deployment (for up to 3 days) in spiked natural freshwater (SNW) resulted in linear mass uptakes for the short-chain ILs (C2-C8), and their DGT-measured concentrations agreed well with solution concentrations. However, MCX-DGT significantly overestimated the concentrations of the long-chain ILs (C10-C12) when deployed in SNW for one day or more, which is attributed to the strong competitive adsorption of the long-chain ILs by natural organic matter. In situ field evaluation along with grab sampling found no target ILs in a wastewater treatment plant and its receiving river, implying that these new chemicals might not be widely used in South China now. This is the first report on the DGT technique for ILs and might provide an effective tool for monitoring short chain length ILs in the aquatic environment in the near future.

The mode of toxic action of ionic liquids: Narrowing down possibilities using high-throughput, in vitro cell-based bioassays

Growing concerns about the environmental impact of ionic liquids (ILs) have spurred research into their (eco)toxic effects, but studies on their mode of toxic action (MOA) still remain limited. However, understanding the MOA and identifying structural features responsible for enhanced toxicity is crucial for characterising the hazard and designing safer alternatives. Therefore, 45 ILs, with systematically varied chemical structures, were tested for cytotoxicity and two specific endpoints in reporter gene assays targeting the Nrf2-ARE mediated oxidative stress response (AREc32) and aryl hydrocarbon receptor activation (AhR-CALUX). While none of the ILs activated the reporter genes, cytotoxicity was high and markedly different between cell lines. Seven and 25 ILs proved more cytotoxic than predicted by baseline toxicity model in the AREc32 and the AhR-CALUX assays, respectively. The length of the side chain and headgroup structures of ILs altered the MOA of ILs. Cellular metabolism of the ILs, investigated by LC-MS/MS, showed side-chain oxidation of the long-chain quaternary ammonium compounds in AhR-CALUX cells and, to a lower extent, in AREc32 cells, however, this transformation could not explain the high cytotoxicity. Effect data for 72 ILs for ten endpoints retrieved from the Tox21 database identified the inhibition of aromatase activity and of mitochondrial membrane potential as potential MOAs. However, in vitro fluorimetric assays for these endpoints demonstrated that effects were activated in a non-specific manner, probably through cytotoxicity. Although many of the ILs tested induced cytotoxicity at concentrations lower than baseline toxicity, the specific MOAs responsible could not be identified. Alternatively, we suggest that the descriptors currently used may fail to define the affinity of ILs for cells. Testing of the affinity of ILs for a diverse range of biomolecules is needed to accurately describe their interactions with cells.

Dietary therapy of murine primary biliary cholangitis induces hepatocellular steatosis: A cautionary tale

BACKGROUND AND AIMS

There is increased interest in utilizing dietary interventions to alter the progression of autoimmune diseases. These efforts are driven by associations of gut microbiota/metabolites with levels of short-chain fatty acids (SCFAs). Propionate is a key SCFA that is commonly used as a food preservative and is endogenously generated by bacterial fermentation of non-digestible carbohydrates in the gut. A thesis has suggested that a diet rich in propionate and other SCFAs can successfully modulate autoimmunity. Herein, we investigated the effect of long-term administration of propionylated high-amylose resistant starches (HAMSP) on the course of murine primary biliary cholangitis.

MATERIALS AND METHODS

Groups of female ARE-Del mice were fed an HAMSP diet either before or after disease onset. A detailed immunobiological analysis was performed involving autoantibodies and rigorous T-cell phenotyping, including enumeration of T-cell subsets in the spleen, liver, intestinal intraepithelial lymphocytes and lamina propria by flow cytometry. Histopathological scores were used to assess the frequency and severity of liver inflammation and damage to hepatocytes and bile ducts.

RESULTS

Our results demonstrate that a long-term propionate-yielding diet re-populated the T-cell pool with decreased naïve and central memory T-cell subsets and an increase in the effector memory T cells in mice. Similarly, long-term HAMSP intake reduced CD4+CD8+ double-positive T cells in intraepithelial lymphocytes and the intestinal lamina propria. Critically, HAMSP consumption led to moderate-to-severe hepatocellular steatosis in ARE-Del mice, independent of the stage of autoimmune cholangitis.

CONCLUSIONS

Our data suggest that administration of HAMSP induces both regulatory and effector T cells. Furthermore, HAMSP administration resulted in hepatocellular steatosis. Given the interest in dietary modulation of autoimmunity and because propionate is widely used as a food preservative, these data have significant implications. This study also provides new insights into the immunological and pathological effects of chronic propionate exposure.

Methylimidazolium ionic liquids - A new class of forever chemicals with endocrine disrupting potential

A class of chemical with a potentially important perceived future contribution to the net zero carbon goal (as "green" solvents) is the methylimidazolium ionic liquids (MILs). These solvents are used in industrial processes such as biofuel production yet little is known about their environmental stability or toxicity in man although one MIL - 1-octyl-3-methylimidazolium (M8OI) - has been shown to activate the human estrogen receptor alpha (ERα). The stabilities of the chloride unsubstituted methylimidazolium (MI) and MILs possessing increasing alkyl chain lengths (2C, 1-ethyl-3-methylimidazolium (EMI); 4C, 1-butyl-3-methylimidazolium (BMI); 6C; 1-hexyl-3-methylimidazolium (HMI), 8C, M8OI; 10C, 1-decyl-3-methylimidazolium (DMI)) were examined in river water and a human liver model system. The MILs were also screened for their abilities to activate the human ERα in vitro and induce uterine growth in pre-pubertal rats in vivo. Short chain MILs (EMI, BMI and HMI) underwent negligible metabolism and mineralisation in river water; were not metabolised in a model of human liver metabolism; activated the human ERα in vitro and were estrogenic in vivo in rats. A structure-based computational approach predicted short chain MIL binding to both the estrogen binding site and an additional site on the human estrogen receptor alpha. Longer chain MILs (M8OI and DMI) were metabolised in river water and partially mineralised. Based on structure-activity considerations, some of these environmentally-derived metabolites may however, remain a hazard to the population. MILs therefore have the potential to become forever chemicals with adverse effects to both man, other animals and the environment in general.

High-sensitivity liquid chromatography-tandem mass spectrometry quantitative for alkyl imidazolium ionic liquids in human serum: Advancing biomonitoring of human exposure concerns

Alkyl imidazolium ionic liquids (Cn[MIM]), initially heralded as eco-friendly green solvents for diverse industrial applications, have increasingly been recognized fortheir biodegradability challenges and multiple biotoxicity. Despite potential health risks, research into the effects of Cn[MIM] on human health remains scarce, particularly regarding their detection in biological serum samples. This study validated a matrix-matched calibration quantitative method that utilizes solid-phase extraction (SPE) coupled with ultrahigh-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The method was used to analyze the presence of 10 ionic liquids (ILs) with varying alkyl carbon chain lengths (C2-C12) across 300 human serum samples. Efficient separation was achieved using optimized SPE conditions and a BEH C18 column with an appropriate mobile phase. Results demonstrated a strong linear relationship (0.05-100 ng/mL; R2 = 0.995-0.999), with detection and quantification limits with detection and quantification limits ranging from 0.001 to 0.107 ng/mL and 0.003-0.355 ng/mL, respectively. Intraday and inter-day precisions were 0.85-6.99 % and 1.50-7.46 %, with recoveries between 82 and 113 %. The validated method detected C6MIM in 19 % of samples and C8MIM in 8.3 % of samples, with concentrations ranging from 0.02 to 111.70 μg/L and 0.09-16.99 μg/L, respectively, suggesting a potential risk of human exposure. This underscores the importance of robust detection methods in monitoring environmental and human health impacts of alkyl imidazolium compounds.

Ionic Liquid 1-Octyl-3-Methylimidazolium (M8OI) Is Mono-Oxygenated by CYP3A4 and CYP3A5 in Adult Human Liver

Environmental sampling around a landfill site in the UK previously identified the methylimidazolium ionic liquid, 1-octyl-3-methylimidazolium (M8OI), in the soil. More recently, M8OI was shown to be detectable in sera from 5/20 PBC patients and 1/10 controls and to be oxidised on the alkyl chain in the human liver. The objective of this study was to examine the metabolism of M8OI in humans in more detail. In human hepatocytes, M8OI was mono-oxygenated to 1-(8-Hydroxyoctyl)-3-methyl-imidazolium (HO8IM) then further oxidised to 1-(7-carboxyheptyl)-3-methyl-1H-imidazol-3-ium (COOH7IM). The addition of ketoconazole-in contrast to a range of other cytochrome P450 inhibitors-blocked M8OI metabolism, suggesting primarily CYP3A-dependent mono-oxygenation of M8OI. Hepatocytes from one donor produced negligible and low levels of HO8IM and COOH7IM, respectively, on incubation with M8OI, when compared to hepatocytes from other donors. This donor had undetectable levels of CYP3A4 protein and low CYP3A enzyme activity. Transcript expression levels for other adult CYP3A isoforms-CYP3A5 and CYP3A43-suggest that a lack of CYP3A4 accounted primarily for this donor's low rate of M8OI oxidation. Insect cell (supersome) expression of various human CYPs identified CYP3A4 as the most active CYP mediating M8OI mono-oxygenation, followed by CYP3A5. HO8IM and COOH7IM were not toxic to human hepatocytes, in contrast to M8OI, and using a pooled preparation of human hepatocytes from five donors, ketoconazole potentiated M8OI toxicity. These data demonstrate that CYP3A initiates the mono-oxygenation and detoxification of M8OI in adult human livers and that CYP3A4 likely plays a major role in this process.

Bioconcentration potential of ionic liquids: New data on membrane partitioning and its comparison with predictions obtained by COSMOmic

Ionic liquids (ILs) have recently gained significant attention in both the scientific community and industry, but there is a limited understanding of the potential risks they might pose to the environment and human health, including their potential to accumulate in organisms. While membrane and storage lipids have been considered as primary sorption phases driving bioaccumulation, in this study we used an in vitro tool known as solid-supported lipid membranes (SSLMs) to investigate the affinity of ILs to membrane lipid - phosphatidylcholine and compare the results with an existing in silico model. Our findings indicate that ILs may have a strong affinity for the lipids that form cell membranes, with the key factor being the length of the cation's side chain. For quaternary ammonium cations, increase in membrane affinity (logMA) was observed from 3.45 ± 0.06 at 10 carbon atoms in chain to 4.79 ± 0.06 at 14 carbon atoms. We also found that the anion can significantly affect the membrane partitioning of the cation, even though the anions themselves tend to have weaker interactions with phospholipids than the cations of ILs. For 1-methyl-3-octylimidazolium cation the presence of tricyanomethanide anion caused increase in logMA to 4.23 ± 0.06. Although some of our data proved to be consistent with predictions made by the COSMOmic model, there are also significant discrepancies. These results suggest that further research is needed to improve our understanding of the mechanisms and structure-activity relationships involved in ILs bioconcentration and to develop more accurate predictive models.

Undifferentiated HepaRG cells show reduced sensitivity to the toxic effects of M8OI through a combination of CYP3A7-mediated oxidation and a reduced reliance on mitochondrial function

The methylimidazolium ionic liquid M8OI (1-octyl-3-methylimidazolium chloride, also known as [C8mim]Cl) has been detected in the environment and may represent a hazard trigger for the autoimmune liver disease primary biliary cholangitis, based in part on studies using a rat liver progenitor cell. The effect of M8OI on an equivalent human liver progenitor (undifferentiated HepaRG cells; u-HepaRG) was therefore examined. u-HepaRG cells were less sensitive (>20-fold) to the toxic effects of M8OI. The relative insensitivity of u-HepaRG cells to M8OI was in part, associated with a detoxification by monooxygenation via CYP3A7 followed by further oxidation to a carboxylic acid. Expression of CYP3A7 - in contrast to the related adult hepatic CYP3A4 and CYP3A5 forms - was confirmed in u-HepaRG cells. However, blocking M8OI metabolism with ketoconazole only partly sensitized u-HepaRG cells. Despite similar proliferation rates, u-HepaRG cells consumed around 75% less oxygen than B-13 cells, reflective of reduced dependence on mitochondrial activity (Crabtree effect). Replacing glucose with galactose, resulted in an increase in u-HepaRG cell sensitivity to M8OI, near similar to that seen in B-13 cells. u-HepaRG cells therefore show reduced sensitivity to the toxic effects of M8OI through a combination of metabolic detoxification and their reduced reliance on mitochondrial function.

Unveiling the molecular interactions between alkyl imidazolium ionic liquids and human serum albumin: Implications for toxicological significance

Alkyl imidazolium-based ionic liquids (ILs) are promising for diverse industrial applications; however, their growing prevalence has raised concerns regarding human exposure and potential health implications. A critical aspect to be clarified to address the adverse health effects associated with ILs exposure is their binding mode to human serum albumin (HSA). In this study, we delved into the binding interactions between three alkyl imidazolium ILs (1-hexyl-3-methyl-imidazolium (C6[MIM]), 1-ethyl-3-methyl-imidazolium chloride (C8[MIM]) and 1-decyl-3-methyl-imidazolium (C10[MIM]) and human serum albumins (HSAs) using a comprehensive approach encompassing molecular docking and multi-spectroscopy (UV-visible, Fluorescence, Circular Dichroism, FTIR). Furthermore, for the first time, we developed an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) approach time to quantify plasma protein binding rates. Our results revealed that the ILs primarily bind to the hydrophobic cavity of HSA through hydrogen bonding and van der Waals forces, forming stable complexes via static quenching. This affected HSA's secondary structure, reducing α-helical content, particularly around specific residues. Equilibrium dialysis and ultrafiltration coupled with UPLC-MS/MS analysis showed modest plasma protein binding rates (17.84%-31.85%) for the three ILs, with no significant influence from alkyl chain effects or concentration relationship. Lower plasma protein binding rates can affect bioavailability and distribution of ILs, potentially influencing their toxicity. These findings provide critical insights into the potential toxicological implications at the molecular level, thereby contributing to continuous efforts to evaluate the risk profiles and ensure the safe utilization of these compounds.

Estrogen receptor alpha-mediated mitochondrial damage in intrahepatic bile duct epithelial cells leading to the pathogenesis of primary biliary cholangitis

This study investigated the effects of estrogen and estrogen receptor alpha (ERα) on the pathogenesis of primary biliary cholangitis (PBC) in human intrahepatic bile duct epithelial cells (HiBECs). The researchers measured serum levels of ERα, oxidative stress indicators, and cytokines in PBC patients and healthy controls. They examined the expression of ERα, pyruvate dehydrogenase complex E2-component (PDC-E2), and apoptosis-related proteins in the small bile ducts. In vitro experiments with HiBECs showed that estrogen had a dual effect on cell viability, increasing it at low concentrations but reducing it at higher concentrations. ERα activation led to mitochondrial damage, apoptosis, and upregulation of ERα and PDC-E2 expression. These findings suggest that the high expression of ERα in the bile ducts contributes to mitochondrial damage, inflammation, and apoptosis in PBC. The study highlights ERα as a potential target for understanding and treating estrogen-mediated PBC pathogenesis.

The effects of the IM1-12Br ionic liquid and the oxytetracycline mixture on selected marine and brackish microorganisms

The number of applications and commercialized processes utilizing ionic liquids has been increasing, and it is anticipated that this trend will persist and even intensify in the future. Ionic liquids possess desirable characteristics, such as low vapor pressure, good water solubility, amphiphilicity, and stability. Nevertheless, these properties can influence their environmental behavior, resulting in resistance to biotic and abiotic degradation and subsequent water contamination with more harmful derivatives. However, there is a notable scarcity of data regarding the impact of mixtures comprising ionic liquids and other micropollutants. Identifying potential potentiation of ionic liquids (Ils) toxicity in the presence of other xenobiotics is a proactive risk assessment measure. Therefore, the study aims to fill an important knowledge gap and identify possible interactions between imidazolium-based ionic liquid (IM1-12Br) and the common antibiotic oxytetracycline (OXTC). During 11-day experiments, selected marine, brackish and freshwater microorganisms (diatom Phaeodactylum tricornutum, cyanobacterium Microcystis aeruginosa and green algae Chlorella vulgaris) were exposed to binary mixtures of target substances. The assessed responses encompassed chlorophyll a kinetic parameters related to photosynthesis efficiency, as well as pigment concentrations, specifically phycobilin content. Additionally, the impact on the luminescent marine bacterium Aliivibrio fischeri has been evaluated. Significant effects on the growth, photosynthetic processes, and pigment content were observed in all the targeted microorganisms. The concentration addition (CA) and independent action (IA) mathematical models followed by the Model Deviation Ratio (MDR) evaluation enabled the identification of mainly synergistic interactions in the studied mixtures. The findings of present study offer valuable insights into the impacts of ionic liquids and other organic micropollutants.

Insight into the negative effect and lipid profile alterations in liver of mice exposed to methylimidazolium ionic liquids, a novel "green" solvent

Background

Ionic liquids (ILs) have been recognized as potential environmentally friendly solvents; however, their potential toxicity to living organisms warrants thorough investigation, particularly for novel-generation ILs in mammalian models.

Methods

In this study, we examined the hepatic effects and disruption of lipid metabolism in mice exposed to 1-heptyl-3-methylimidazolium chloride (C7[MIM]Cl), a novel ILs. After four weeks of oral administration at different dosages (2.38, 5.95, and 11.9 mg/kg b.w.), we conducted clinical chemistry analysis and histopathological examination of the liver to assess biochemical and structural changes.

Results

The low-dose C7[MIM]Cl group exhibited a significant increase in alanine aminotransferase (ALT) levels, while aspartate aminotransferase (AST) levels were elevated in both low-dose and high-dose groups without statistical significance. Histopathological examination showed inflammatory cell infiltration and red blood cell aggregation in the livers of mice exposed to C7[MIM]Cl, particularly in the high-dose group. Oxidative stress levels showed moderate changes in response to C7[MIM]Cl exposure. Notably, hepatic biochemical parameters revealed a dose-dependent increase in triglycerides (TG) levels with statistically significant differences compared to the control group (P ≤ 0.01). Targeted lipidomic analysis revealed notable alterations in liver lipids of mice exposed to C7[MIM]Cl, with lysophosphatidylethanolamine (18:0), phosphatidylcholines (18:0), and phosphatidylcholines (19:0) identified as critical lipids associated with C7[MIM]Cl exposure. Furthermore, metabolic pathway analyses demonstrated significant disturbances in the glycerophospholipid metabolic pathway.

Conclusion

These findings provide valuable insights into the hepatic effects of C7[MIM]Cl exposure and novel perspectives on the disruption of lipid metabolism underlying ILs toxicity.

Ionic-Liquid-Mediated Deconstruction of Polymers for Advanced Recycling and Upcycling

Ionic liquids (ILs) are a promising medium to assist in the advanced (chemical and biological) recycling of polymers, owing to their tunable catalytic activity, tailorable chemical functionality, low vapor pressures, and thermal stability. These unique physicochemical properties, combined with ILs' capacity to solubilize plastics waste and biopolymers, offer routes to deconstruct polymers at reduced temperatures (and lower energy inputs) versus conventional bulk and solvent-based methods, while also minimizing unwanted side reactions. In this Viewpoint, we discuss the use of ILs as catalysts and mediators in advanced recycling, with an emphasis on chemical recycling, by examining the interplay between IL chemistry and deconstruction thermodynamics, deconstruction kinetics, IL recovery, and product recovery. We also consider several potential environmental benefits and concerns associated with employing ILs for advanced recycling over bulk- or solvent-mediated deconstruction techniques, such as reduced chemical escape by volatilization, decreased energy demands, toxicity, and environmental persistence. By analyzing IL-mediated polymer deconstruction across a breadth of macromolecular systems, we identify recent innovations, current challenges, and future opportunities in IL application toward circular polymer economies.

Thyroid endocrine disruption induced by [C8mim]Br: An integrated in vivo, in vitro, and in silico study

Conventional thyroid-disrupting chemicals (TDCs) such as polybrominated diphenyl ethers, polychlorinated biphenyls, and bisphenols perturb animal's thyroid endocrine system by mimicking the action of endogenous thyroid hormones (THs), since they share a similar backbone structure of coupled benzene rings with THs. 1-methyl-3-octylimidazolium bromide ([C₈mim]Br), a commonly used ionic liquid (IL), has no structural similarity to THs. Whether it interferes with thyroid function and how its mode of action differs from conventional TDCs is largely unknown. Herein, zebrafish embryo-larvae experiments (in vivo), GH3 cell line studies (in vitro), and molecular simulation analyses (in silico) were carried out to explore the effect of [C₈mim]Br on thyroid homeostasis and its underlying mechanism. Molecular docking results suggested that [C₈mim]⁺ likely bound to retinoid X receptors (RXRs), which may compromise the formation of TH receptor/RXR heterodimers. This then perturbed the negative regulation of thyroid-stimulating hormone β (tshβ) transcription by T3 in GH3 cell line. The resulting enhancement of tshβ expression further caused hyperthyroidism and developmental toxicity in larval zebrafish. These findings provided a crucial aspect of the ecological risks of ILs, and presented a new insight into the thyroid-disrupting mechanisms for emerging pollutants that do not have structural similarity to THs.

The methylimidazolium ionic liquid M8OI is a substrate for OCT1 and p-glycoprotein-1 in rat

The methylimidazolium ionic liquid M8OI was recently found to be present in both the environment and man. In this study, M8OI disposition and toxicity were examined in an established rat progenitor-hepatocyte model. The progenitor B-13 cell was approx. 13 fold more sensitive to the toxic effects of M8OI than the hepatocyte B-13/H cell. However, this difference in sensitivity was not associated with a difference in metabolic capacities. M8OI toxicity was significantly decreased in a dose-dependent manner by co-addition of the OCT1 (SLC22A1) inhibitor clonidine, but not by OCT2 or OCT3 inhibitors in B-13 cells. M8OI toxicity was also dose-dependently increased by the co-addition of p-glycoprotein-1 (ABCB1B, multi drug resistant protein 1 (MDR1)) substrates/inhibitors. Excretion of B-13-loaded fluorophore Hoechst 33342 was also inhibited by the p-glycoproteins substrate cyclosporin A and by M8OI in a dose-dependent manner. Comparing levels of OCT and p-glycoprotein transcripts and proteins in B-13 and B-13/H cells suggest that the lower sensitivity to M8OI in B-13/H cells is predominantly associated with their higher expression of p-glycoprotein-1. These data together therefore suggest that a determinant in M8OI toxicity in rats is the expression and activity of the p-glycoprotein-1 transporter.

1-Butyl-3-methylimidazolium Chloride Affects Anaerobic Digestion through Altering Organics Transformation, Cell Viability, and Microbial Community

1-Butyl-3-methylimidazolium chloride (BmimCl), an imidazolium-based ionic liquid, is considered the representative emerging persistent aquatic pollutant, and its environmental toxicity has attracted a growing concern. However, most of the investigations focused on monocultures or a single organism, with little information available on the complex syntrophic consortium that dominates the complex and successional biochemical processes, such as anaerobic digestion. In this study, the effect of BmimCl at environmentally relevant levels on glucose anaerobic digestion was therefore investigated in several laboratory-scale mesophilic anaerobic digesters to provide such support. Experimental results showed that BmimCl at 1-20 mg/L inhibited the methane production rate by 3.50-31.03%, and 20 mg/L BmimCl inhibited butyrate, hydrogen, and acetate biotransformation by 14.29%, 36.36%, and 11.57%, respectively. Toxicological mechanism studies revealed that extracellular polymeric substances (EPSs) adsorbed and accumulated BmimCl through carboxyl, amino, and hydroxyl groups, which destroyed the EPSs' conformational structure, thereby leading to the inactivation of microbial cells. MiSeq sequencing data indicated that the abundance of Clostridium_sensu_stricto_1, Bacteroides, and Methanothrix decreased by 6.01%, 7.02%, and 18.45%, respectively, in response to 20 mg/L BmimCl. Molecular ecological network analysis showed that compared with the control, the lower network complexity, fewer keystone taxa, and fewer associations among microbial taxa were found in the BmimCl-present digester, indicating the reduced stability of the microbial community.

Potential for cardiac toxicity with methylimidazolium ionic liquids

Methylimidazolium ionic liquids (MILs) are solvent chemicals used in industry. Recent work suggests that MILs are beginning to contaminate the environment and lead to exposure in the general population. In this study, the potential for MILs to cause cardiac toxicity has been examined. The effects of 5 chloride MIL salts possessing increasing alkyl chain lengths (2 C, EMI; 4 C, BMI; 6 C; HMI, 8 C, M8OI; 10 C, DMI) on rat neonatal cardiomyocyte beat rate, beat amplitude and cell survival were initially examined. Increasing alkyl chain length resulted in increasing adverse effects, with effects seen at 10^-5 M at all endpoints with M8OI and DMI, the lowest concentration tested. A limited sub-acute toxicity study in rats identified potential cardiotoxic effects with longer chain MILs (HMI, M8OI and DMI) based on clinical chemistry. A 5 month oral/drinking water study with these MILs confirmed cardiotoxicity based on histopathology and clinical chemistry endpoints. Since previous studies in mice did not identify the heart as a target organ, the likely cause of the species difference was investigated. qRT-PCR and Western blotting identified a marked higher expression of p-glycoprotein-3 (also known as ABCB4 or MDR2) and the breast cancer related protein transporter BCRP (also known as ABCG2) in mouse, compared to rat heart. Addition of the BCRP inhibitor Ko143 - but not the p-glycoproteins inhibitor cyclosporin A - increased mouse cardiomyocyte HL-1 cell sensitivity to longer chain MILs to a limited extent. MILs therefore have a potential for cardiotoxicity in rats. Mice may be less sensitive to cardiotoxicity from MILs due in part, to increased excretion via higher levels of cardiac BCRP expression and/or function. MILs alone, therefore may represent a hazard in man in the future, particularly if use levels increase. The impact that MILs exposure has on sensitivity to cardiotoxic drugs, heart disease and other chronic diseases is unknown.

Salinity fluctuation influences the toxicity of 1-octyl-3-methylimidazolium chloride ([C8mim]Cl) to a marine diatom Phaeodactylum tricornutum

In this work, a marine diatom (Phaeodactylum tricornutum) was exposed to 1-octyl-3-methylimidazolium chloride ([C₈mim]Cl) for 96 h at three different salinities (25, 35, and 45 ‰) for investigating their interactive effects. Results showed that values of EC₁₀ and EC₅₀ at 96 h of exposure were 0.29, 1.06, 2.01 μg L^-1 and 7.21, 7.71, 7.25 mg L^-1 when the salinities were 25, 35, and 45 ‰, respectively, meaning that salinity fluctuation affected the toxicity of [C₈mim]Cl to this diatom. Changes in chlorophyll a contents and chlorophyll fluorescence parameters suggested that [C₈mim]Cl and salinity fluctuation had a significant interactive effect on the algal photosynthesis. In addition, soluble protein content and activities of antioxidant enzymes in algal cells changed significantly. Increased malondialdehyde contents indicated that the combined stresses could induce excessive production of reactive oxygen species leading to oxidative damage to the algal cells.

Immunologic Responses and the Pathophysiology of Primary Biliary Cholangitis

Primary biliary cholangitis (PBC) is an autoimmune liver disease with a female predisposition and selective destruction of intrahepatic small bile ducts leading to nonsuppurative destructive cholangitis. It is characterized by seropositivity of antimitochondrial antibodies or PBC-specific antinuclear antibodies, progressive cholestasis, and typical liver histologic manifestations. Destruction of the protective bicarbonate-rich umbrella is attributed to the decreased expression of membrane transporters in biliary epithelial cells (BECs), leading to the accumulation of hydrophobic bile acids and sensitizing BECs to apoptosis. A recent X-wide association study reveals a novel risk locus on the X chromosome, which reiterates the importance of Treg cells.

Contemporary Epidemiology of Primary Biliary Cholangitis

Primary biliary cholangitis (PBC) is a cholestatic liver disease with potential evolution to liver cirrhosis when left untreated. Despite being rare, PBC has a substantial impact on the quality of life and survival of affected patients. Women are the most diagnosed worldwide; however, male subjects seem to have more aggressive disease and worse prognosis. Changing epidemiologic trends are emerging in PBC, with increasing global prevalence and slight smoothing of sex differences. In this review we present available data on incidence rates and prevalence of PBC worldwide, highlighting geographic differences and factors impacting clinical outcomes.

Ionic liquids as potentially hazardous pollutants: Evidences of their presence in the environment and recent analytical developments

Ionic liquids (ILs) are considered to be very promising group of chemicals and the number of their potential applications is growing rapidly. However, while these compounds were originally proposed as a green alternative to classical solvents, there are certain doubts as to whether this classification is correct. Although in recent years there have been first reports published proving the presence of some ILs in the environment and even in human blood, at this point the scale of this possible problem is not yet fully understood. However, there is no doubt that as the number of ILs applications increases, analytical capabilities for rapid detection of possible environmental contamination should be also considered. Therefore, in this review paper, recent evidences for the ILs environmental contamination as well as analytical achievements related to the extraction of ILs from various environmental matrices have been summarized and important gaps and future perspectives have been pointed out. Based on the presented data it might be concluded that there is the urgent need for further development towards risk assessment of these potential environmental contaminants.

Neurotoxicity of Chronic Co-Exposure of Lead and Ionic Liquid in Common Carp: Synergistic or Antagonistic?

Previous studies have indicated that the harmful heavy metal lead (Pb) contamination in aquatic systems has caused intelligence development disorders and nervous system function abnormalities in juveniles due to the increased permeability of the blood-brain barrier. Ionic liquids (ILs) are considered "green" organic solvents that can replace traditional organic solvents. Studies have found the presence of ILs in soil and water due to chemical applications or unintentional leakage. Therefore, what would happen if Pb interacted with ILs in a body of water? Could ILs enable Pb to more easily cross the blood-brain barrier? Therefore, we examined the combined exposure of Pb and ILs in common carp at low concentration (18.3 mg L^-1 of Pb(CH₃COO)₂•3 H₂O and 11 mg L^-1 of the IL 1-methyl-3-octylimidazolium chloride, 5% of their LC₅₀) for 28 days in the present study. The result of a neurobehavioral assay showed that chronic exposure of lead at lower concentrations significantly altered fish movement and neurobehaviors, indicating that lead exposure caused neurotoxicity in the carp. Increases in the neurotransmitter dopamine levels and injuries in the fish brain accounted for neurobehavioral abnormalities induced by lead exposure. Moreover, we also found that lead could easily cross the blood-brain barrier and caused significant bioaccumulation in the brain. Particularly, our study indicated that the ionic liquid could not synergistically promote blood-brain barrier permeability and hence failed to increase the absorption of lead in the fish brain, suggesting that the combined exposure of lead and ILs was not a synergistic effect but antagonism to the neurotoxicity. The results of this study suggested that ILs could recede the Pb induced neurotoxicity in fish.

Effect of Acute Exposure to the Ionic Liquid 1-Methyl-3-octylimidazolium Chloride on the Embryonic Development and Larval Thyroid System of Zebrafish

Simple Summary

In this study, we aimed to evaluate the effect of acute exposure to the ionic liquid 1-methyl-3-octylimidazolium chloride on the embryonic development and larval thyroid system of zebrafish. The results showed that the fish embryonic development, thyroid hormone level, and expression of HPTs-related genes were altered, suggesting that the ionic liquid [C8mim]Cl might pose an aquatic environmental threat to fish.

Abstract

Previous studies have shown that ILs can induce toxicity in animals, plants, and cells. However, the effect of imidazolium-based ILs on the hypothalamus–pituitary–thyroid (HPT) axis of fish remains unknown. The present study aimed to evaluate the acute effect of [C8mim]Cl on the embryonic development and thyroid-controlled internal secretion system of zebrafish by determining the thyroid hormone level and the expression of HPT-related genes. The results obtained for embryonic developmental toxicity showed the survival rate, heart beats, and body length of fish had decreased 96 h after exposure to [C8mim]Cl, but the hatching rate had increased by the 48 h time point. The transcription levels of HTP-related genes showed that the genes dio3, tg, ttr, tsh, trhrα, trhrβ, trhr2, and tpo were up-regulated, while the expression levels of dio1, trh, tshr, and nis were significantly suppressed. Furthermore, we found that exposure to [C8mim]Cl induced an alteration in the levels of thyroid hormones that increased the T3 but decreased the T4 content. In conclusion, our study indicated that acute exposure to [C8mim]Cl altered the expression of HTP-related genes and disturbed the thyroid hormone level, suggesting that the ionic liquid [C8mim]Cl might pose an aquatic environmental threat to fish.

The Role of Epigenetics in Primary Biliary Cholangitis

Primary Biliary Cholangitis (PBC) is a rare autoimmune disease of the liver, affecting mostly females. There is evidence that epigenetic changes have a pathogenic role in PBC. Epigenetic modifications are related to methylation of CpG DNA islands, post-translational modifications of histone proteins, and non-coding RNAs. In PBC, there are data showing a dysregulation of all these levels, especially in immune cells. In addition, epigenetics seems to be involved in complex phenomena such as X monosomy or abnormalities in the process of X chromosome inactivation, which have been reported in PBC and appear to influence its sex imbalance and pathogenesis. We review here historical data on epigenetic modifications in PBC, present new data, and discuss possible links among X-chromosome abnormalities at a genetic and epigenetic level, PBC pathogenesis, and PBC sex imbalance.

Intermittent multi-generational effects of 1-hexyl-3-methylimidazolium nitrate on Caenorhabditis elegans mediated by lipid metabolism

Ionic liquids (ILs) become environmental pollutants. Their environmental toxicities included inhibitory effects, stimulatory ones and hormesis combining both aspects on various organisms. However, the mechanisms still need systematic investigations. Presently, 1-hexyl-3-methylimidazolium nitrate ([Hmim]NO₃) was chosen as one representative IL. Its effects on lifespan and reproduction were studied on C. elegans with lipid metabolism as the potential mechanism. Two types (A and B) intermittent multi-generational exposure arrangements were set up to mimic realistic ILs exposure scenarios. Type A arrangement had exposure in F1, F5 and F9 with recovery in T2-T4, T6-T8 and T10-T12, and type B arrangement had exposure in F1, F3, F5, F7, F9 and F11 with recovery in T2, T4, T6, T8, T10 and T12. In type A exposure, the effects of [Hmim]NO₃ on reproduction were 1.32-, 1.68-, 1.23-, 0.96-, 1.68-, 1.07-, 1.25-, 1.64-, 1.31-, 1.11-, 0.89- and 1.02-fold of the control in F1, T2-T4, F5, T6-T8, F9, T10-T12, respectively. The results showed oscillation between stimulatory and inhibitory effects. In type B exposure, the effects showed fewer inhibitions and more stimulations across generations. Moreover, the effects on reproduction showed trade-off relationships with lifespan, and the trade-off was more obvious in type B exposure. Further biochemical and gene expression analysis showed that lipid metabolism was closely related with lifespan and reproduction in type A exposure, but it was connected with cholesterol synthesis in type B exposure. The results demonstrated different strategies in the biological responses to the two arrangements of intermittent multi-generational exposure.

Biosafety-inspired structural optimization of triazolium ionic liquids based on structure-toxicity relationships

Ionic liquids (ILs), owing to their low vapor pressure and excellent solvating ability, are being increasingly applied in various industries to replace highly toxic organic solvents. They mainly pollute aquatic environment and soils, directly endangering eco-environment and human health. Therefore, it is critical to understand and optimize structural motifs of ILs with reduced toxicity. Considering human oral exposure is the major route, our investigations employed a human cell panel (modeling oral exposures) including human stomach (GES-1), intestinal (FHC), liver (HepG2) and kidney (HEK293) cells using a series of experimental and computational approaches to explore the cytotoxicity and molecular mechanism of ILs. We discovered that the cytotoxicity of triazolium and imidazolium ILs was human cell line-dependent with cytotoxicity in an order of FHC > GES-1 > HepG2 > HEK293. For this reason, a toxicity assay using a single cell line was highly inappropriate. Compared to anions (Br^-, OTs^-, OTMBS^-) we tested, the cation of ILs played a major role in causing cytotoxicity. Ionic liquids with cations having longer hydrophobic sidechains (IL09 vs. IL01) readily insert into cell membranes with enhanced membrane and lipidomic perturbations, induce cytotoxicity by triggering cell cycle arrest and apoptosis. Reducing sidechain length and incorporating three nitrogen atoms (triazolium) instead of two (imidazolium) in the cation core alleviated cytotoxicity by reducing cell membrane perturbations and cell function interference. These findings provide important guiding principles for the design of the next-generation of "green" and safe ILs.

Selected transgenic murine models of human autoimmune liver diseases

Murine models of human diseases are of outmost importance for both studying molecular mechanisms driving their development and testing new treatment strategies. In this review, we first discuss the etiology and risk factors for autoimmune liver disease, including primary biliary cholangitis, autoimmune hepatitis and primary sclerosing cholangitis. Second, we highlight important features of murine transgenic models that make them useful for basic scientists, drug developers and clinical researchers. Next, a brief description of each disease is followed by the characterization of selected animal models.

Interaction of imidazolium-based ionic liquids with supported phospholipid bilayers as model biomembranes

The cytotoxicity of ionic liquids (ILs) is receiving increasing attention due to their potential biological and environmental impact. We have used atomic force microscopy to investigate the interaction of ILs with supported phospholipid bilayers, as models of biomembranes.

Environmental factors, medical and family history, and comorbidities associated with primary biliary cholangitis in Japan: a multicenter case-control study

BACKGROUND

Primary biliary cholangitis (PBC) is considered to be caused by the interaction between genetic background and environmental triggers. Previous case-control studies have indicated the associations of environmental factors (tobacco smoking, a history of urinary tract infection, and hair dye) use with PBC. Therefore, we conducted a multicenter case-control study to identify the environmental factors associated with the development of PBC in Japan.

METHODS

From 21 participating centers in Japan, we prospectively enrolled 548 patients with PBC (male/female = 78/470, median age 66), and 548 age- and sex-matched controls. These participants completed a questionnaire comprising 121 items with respect to demographic, anthropometric, socioeconomic features, lifestyle, medical/familial history, and reproductive history in female individuals. The association was determined using conditional multivariate logistic regression analysis.

RESULTS

The identified factors were vault toilet at home in childhood [odds ratio (OR), 1.63; 95% confidence interval (CI), 1.01-2.62], unpaved roads around the house in childhood (OR, 1.43; 95% CI, 1.07-1.92), ever smoking (OR, 1.70; 95% CI, 1.28-2.25), and hair dye use (OR, 1.57; 95% CI, 1.15-2.14) in the model for lifestyle factors, and a history of any type of autoimmune disease (OR, 8.74; 95% CI, 3.99-19.13), a history of Cesarean section (OR, 0.20; 95% CI, 0.077-0.53), and presence of PBC in first-degree relatives (OR, 21.1; 95% CI, 6.52-68.0) in the model for medical and familial factors.

CONCLUSIONS

These results suggest that poor environmental hygiene in childhood (vault toilets and unpaved roads) and chronic exposure to chemicals (smoking and hair dye use) are likely to be risk factors for the development of PBC in Japan.

Molecular response mechanisms of silkworm (Bombyx mori L.) to the toxicity of 1-octyl-3-methylimidazole chloride based on transcriptome analysis of midguts and silk glands

In a previous study, silkworm larvae were used as a novel model to assess the biotoxicity of ILs, which showed that ILs could cause significant physiological and biochemical changes in midguts and silk glands of the larvae, and result in the death of larvae. In order to investigate the toxicity of 1-octyl-3-methylimidazole chloride ([C₈mim]Cl) to the larvae at molecular level, RNA-sequencing technology was used to construct transcriptomic profiles of midguts and silk glands in this work. Results showed that a lot of differentially expressed genes (DEGs) were effectively screened out through bioinformatics software based on the transcriptome data and reference genome. To give more detail, 5118 and 2211 DEGs (926 and 822 DEGs) were obtained in the midguts (silk glands) when the larvae were exposed to [C₈mim]Cl for 6 and 12 h, respectively, relative to the controls. In addition, gene ontology (GO) analysis suggested that the DEGs could be divided into three categories (i.e., biological process, cellular component, and molecular function), and were involved in multiple organelle functions and complex biological processes. Kyoto encyclopedia of genes and genomes (KEGG) analysis showed that the DEGs were enriched in a variety of pathways, such as signal transduction, apoptosis, glycolysis, peroxisome, autophagy, hippo signaling pathway, arginine and proline metabolism. Results of quantitative real-time PCR and histopathological observation indicated that molecular mechanism of the larvae against [C₈mim]Cl toxicology may be attributed to cell apoptosis regulation via both the mitochondrial pathway and the death receptor-initiated pathway. Thus, these results provided useful data for exploring the toxicity of ILs to insects at molecular level.

Emerging impacts of ionic liquids on eco-environmental safety and human health

Owing to their unique physicochemical properties, ionic liquids (ILs) have been rapidly applied in diverse areas, such as organic synthesis, electrochemistry, analytical chemistry, functional materials, pharmaceutics, and biomedicine. The increase in the production and application of ILs has resulted in their release into aquatic and terrestrial environments. Because of their low vapor pressure, ILs cause very little pollution in the atmosphere compared to organic solvents. However, ILs are highly persistent in aquatic and terrestrial environments due to their stability, and therefore, potentially threaten the safety of eco-environments and human health. Specifically, the environmental translocation and retention of ILs, or their accumulation in organisms, are all related to their physiochemical properties, such as hydrophobicity. Based on results of ecotoxicity, cytotoxicity, and toxicity in mammalian models, the mechanisms involved in IL-induced toxicity include damage of cell membranes and induction of oxidative stress. Recently, artificial intelligence and machine learning techniques have been used in mining and modeling toxicity data to make meaningful predictions. Major future challenges are also discussed. This review will accelerate our understanding of the safety issues of ILs and serve as a guideline for the design of the next generation of ILs.

Comprehensive Interrogation on Acetylcholinesterase Inhibition by Ionic Liquids Using Machine Learning and Molecular Modeling

Quantitative structure-activity relationship (QSAR) modeling can be used to predict the toxicity of ionic liquids (ILs), but most QSAR models have been constructed by arbitrarily selecting one machine learning method and ignored the overall interactions between ILs and biological systems, such as proteins. In order to obtain more reliable and interpretable QSAR models and reveal the related molecular mechanism, we performed a systematic analysis of acetylcholinesterase (AChE) inhibition by 153 ILs using machine learning and molecular modeling. Our results showed that more reliable and stable QSAR models (R² > 0.85 for both cross-validation and external validation) were obtained by combining the results from multiple machine learning approaches. In addition, molecular docking results revealed that the cations and organic anions of ILs bound to specific amino acid residues of AChE through noncovalent interactions such as π interactions and hydrogen bonds. The calculation results of binding free energy showed that an electrostatic interaction (ΔE_ele < -285 kJ/mol) was the main driving force for the binding of ILs to AChE. The overall findings from this investigation demonstrate that a systematic approach is much more convincing. Future research in this direction will help design the next generation of biosafe ILs.

Advances Brought by Hydrophilic Ionic Liquids in Fields Involving Pharmaceuticals

The negligible volatility and high tunable nature of ionic liquids (ILs) have been the main drivers of their investigation in a wide diversity of fields, among which is their application in areas involving pharmaceuticals. Although most literature dealing with ILs is still majorly devoted to hydrophobic ILs, evidence on the potential of hydrophilic ILs have been increasingly provided in the past decade, viz., ILs with improved therapeutic efficiency and bioavailability, ILs with the ability to increase drugs' aqueous solubility, ILs with enhanced extraction performance for pharmaceuticals when employed in biphasic systems and other techniques, and ILs displaying low eco/cyto/toxicity and beneficial biological activities. Given their relevance, it is here overviewed the applications of hydrophilic ILs in fields involving pharmaceuticals, particularly focusing on achievements and advances witnessed during the last decade. The application of hydrophilic ILs within fields involving pharmaceuticals is here critically discussed according to four categories: (i) to improve pharmaceuticals solubility, envisioning improved bioavailability; (ii) as IL-based drug delivery systems; (iii) as pretreatment techniques to improve analytical methods performance dealing with pharmaceuticals, and (iv) in the recovery and purification of pharmaceuticals using IL-based systems. Key factors in the selection of appropriate ILs are identified. Insights and perspectives to bring renewed and effective solutions involving ILs able to compete with current commercial technologies are finally provided.

Dysfunctional Immune Regulation in Autoimmune Hepatitis: From Pathogenesis to Novel Therapies

Autoimmune hepatitis (AIH) is a chronic inflammatory disorder characterized by hypergammaglobulinemia, presence of serum autoantibodies and histological features of interface hepatitis. AIH therapeutic management still relies on the administration of corticosteroids, azathioprine and other immunosuppressants like calcineurin inhibitors and mycophenolate mofetil. Withdrawal of immunosuppression often results in disease relapse, and, in some cases, therapy is ineffective or associated with serious side effects. Understanding the mechanisms underlying AIH pathogenesis is therefore of paramount importance to develop more effective and well tolerated agents capable of restoring immunotolerance to liver autoantigens. Imbalance between effector and regulatory cells permits liver damage perpetuation and progression in AIH. Impaired expression and regulation of CD39, an ectoenzyme key to immunotolerance maintenance, have been reported in Tregs and effector Th17-cells derived from AIH patients. Interference with these altered immunoregulatory pathways may open new therapeutic avenues that, in addition to limiting aberrant inflammatory responses, would also reconstitute immune homeostasis. In this review, we highlight the most recent findings in AIH immunopathogenesis and discuss how these could inform and direct the development of novel therapeutic tools.

Multi- and trans-generational effects of N-butylpyridium chloride on reproduction, lifespan, and pro/antioxidant status in Caenorhabditis elegans

Ionic liquids (ILs) became emerging pollutants. Their poor degradation and accumulation in organisms urged studies on the long-term effects and also the underlying mechanisms. Currently, 1-butylpyrinium chloride ([bpyr]Cl) was chosen to represent the pyridine-based ILs. Its multi-generational effects were measured on C. elegans for 14 consecutive generations (F1 to F14), and the trans-generational effects were also measured in the great-grand-children (T3 and T3') of F1 and F14. The multi-generational results from F1 to F14 showed that the effects of [bpyr]Cl on the initial and total reproduction and lifespan showed oscillation between inhibition and stimulation. Notably, hormetic effects on reproduction were observed in F7 to F10. The trans-generational effects in T3 and T3' showed different residual consequences between one generational exposure (F1) and multiple generational exposure (F14). Further biochemical analysis showed that the pro/antioxidant status also showed oscillation between inhibition and stimulation. The oscillation levels were greater in superoxide dismutase (SOD), catalase (CAT) and protein carbonyl content (PC) than those in glutathione peroxidase (GSH-Px), reactive oxygen species (ROS) and hydroxyl radical (OH). The pro/antioxidant status contributed to both multi- and trans-generational effects of [bpyr]Cl. Future studies should pay attentions to the long-term influence of ILs and also epigenetic explanations.

The methylimidazolium ionic liquid M8OI is detectable in human sera and is subject to biliary excretion in perfused human liver

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M8OI was recently found to be contaminating the environment.

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M8OI was detected in the sera from 5/20 PBC patients and 1/10 controls.

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M8OI is taken up by human liver hepatocytes.

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M8OI is sequentially metabolised by CYPs followed by oxidation by dehydrogenases.

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The final carboxylic acid metabolite COOH7IM is, in part, excreted into human bile.

A methylimidizolium ionic liquid (M8OI) was recently found to be contaminating the environment and to be related to and/or potentially a component of an environmental trigger for the autoimmune liver disease primary biliary cholangitis (PBC). The aims of this study were to investigate human exposure to M8OI, hepatic metabolism and excretion. PBC patient and control sera were screened for the presence of M8OI. Human livers were perfused with 50μM M8OI in a closed circuit and its hepatic disposition examined. Metabolism was examined in cultured human hepatocytes and differentiated HepaRG cells by the addition of M8OI and metabolites in the range 10–100 μM. M8OI was detected in the sera from 5/20 PBC patients and 1/10 controls. In perfused livers, M8OI was cleared from the plasma with its appearance – primarily in the form of its hydroxylated (HO8IM) and carboxylated (COOH7IM) products – in the bile. Metabolism was reflected in cultured hepatocytes with HO8IM production inhibited by the cytochrome P450 inhibitor ketoconazole. Further oxidation of HO8IM to COOH7IM was sequentially inhibited by the alcohol and acetaldehyde dehydrogenase inhibitors 4-methyl pyrazole and disulfiram respectively. Hepatocytes from 1 donor failed to metabolise M8OI to COOH7IM over a 24 h period. These results demonstrate exposure to M8OI in the human population, monooxygenation by cytochromes P450 followed by alcohol and acetaldehyde dehydrogenase oxidation to a carboxylic acid that are excreted, in part, via the bile in human liver.

Evaluating the hazardous impact of ionic liquids - Challenges and opportunities

Ionic liquids (ILs), being related to the design of new environmentally friendly solvents, are widely considered for applications within the "green chemistry" concept. Due to their unique properties and wide diversity, ILs allow tailoring new separation procedures and producing new materials for advanced applications. However, despite the promising technical performance, environmental concerns highlighted in recent studies focused on the toxicity and biodegradability of ILs and their metabolites have revealed that ILs safety labels are not as benign as previously claimed. This review refers to the fundamentals about the properties and applications of ILs also in the context of their potential environmental effect. Toxicological issues and harmful effects related to the use of ILs are discussed, including the evaluation of their biodegradability and ecological impact on diverse organisms and ecosystems, also with respect to bacteria, fungi, and cell cultures. In addition, this review covers the tools used to assess the toxicity of ILs, including the predictive computational models and the results of studies involving cell membrane models and molecular simulations. Summing up the knowledge available so far, there are still no reliable criteria for unequivocal attribution of toxicity and environmental impact credentials for ILs, which is a challenging research task.

Identification of a Latitude Gradient in the Prevalence of Primary Biliary Cholangitis

INTRODUCTION

The prevalence of primary biliary cholangitis (PBC) reported in different countries varies significantly and seems to have a latitudinal gradient with the highest prevalence reported in higher latitudes, as has been observed with other autoimmune diseases. This study aimed to determine whether there is a latitudinal gradient of PBC prevalence in Australia using 2 methods of case ascertainment.

METHODS

We investigated the latitudinal variation of PBC prevalence across the states and territories of Australia (latitudinal range 18.0°-42.7°S) using pathology-based (private pathology antimitochondrial antibody results and PBC-specific prescription databases (prescriptions for ursodeoxycholic acid, the only publicly subsidized treatment for this disease).

RESULTS

PBC prevalence was significantly positively associated with latitude, and the postcodes in the highest quintile of latitude (encompassing the south coastal areas of the Australian mainland and Tasmania; latitude range -37.75° to -42.72°) had a prevalence estimate that was 1.78 times higher using the pathology-based prevalence estimation than those in the lowest quintile (encompassing tropical and southern Queensland; latitude range -18.02° to -27.59°). Comparing prevalence estimates between states/territories, the result was 2.53 and 2.21 times higher in Tasmania compared with Queensland when using the pathology-based and prescription-based methods, respectively.

DISCUSSION

Using 2 different case-ascertainment methods, we have demonstrated that prevalence estimates of PBC vary significantly with latitude in Australia. Further studies are needed to determine whether factors such as variations in ultraviolet radiation exposure and/or vitamin D levels are responsible for this observation and to investigate the latitudinal prevalence of PBC in other populations.

Fibrotic Events in the Progression of Cholestatic Liver Disease

Cholestatic liver diseases including primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC) are associated with active hepatic fibrogenesis, which can ultimately lead to the development of cirrhosis. However, the exact relationship between the development of liver fibrosis and the progression of cholestatic liver disease remains elusive. Periductular fibroblasts located around the bile ducts seem biologically different from hepatic stellate cells (HSCs). The fibrotic events in these clinical conditions appear to be related to complex crosstalk between immune/inflammatory mechanisms, cytokine signalling, and perturbed homeostasis between cholangiocytes and mesenchymal cells. Several animal models including bile duct ligation (BDL) and the Mdr2-knockout mice have improved our understanding of mechanisms underlying chronic cholestasis. In the present review, we aim to elucidate the mechanisms of fibrosis in order to help to identify potential diagnostic and therapeutic targets.

Reproductive toxicities of 1-ethyl-3-methylimidazolium bromide on Caenorhabditis elegans with oscillation between inhibition and stimulation over generations

Ionic liquids (ILs) become emerging pollutants and their toxicities earn increasing attentions. Yet, their effects were seldom explored on reproduction which connects generations and also effects across generations. In the present study, reproductive effects of 1-ethyl-3-methylimidazolium bromide ([C₂mim]Br), one representative IL, were studied on C. elegans with 11 continuously exposed generations (F1 to F11). At 8.20E-5 g/L, the effects on the initial reproduction showed oscillatory changes between stimulation (in F1, F3, F4, F6 and F10) and inhibition (in F2, F5, F7, F8 and F11). At 8.20E-3 g/L, the effects on the reproduction over generations also showed such oscillation despite of different stimulation or inhibition levels, and even opposite influences in F4 and F11. The effects of [C₂mim]Br on the total reproduction also showed the concentration-dependent oscillation between stimulation and inhibition over generations, though they had less alteration frequencies than those on the initial reproduction. Biochemical and molecular indicators were further measured in F1, F4, F7 and F11 to explore potential mechanisms. Results showed that the effects on spermatocyte protein 8 (SPE8) showed positive correlation with those on reproduction while the influences on major sperm protein (MSP) and sperm transmembrane protein 9 (SPE9) showed negative correlation with SPE8. Moreover, the dysregulation on expressions of acs-2 and akt-1 indicated the involvement of glucolipid metabolism. The changes in expressions of set-2, met-2, set-25 and mes-4 demonstrated that the long-term reproductive impacts of [C₂mim]Br over generations also involved histone methylation at H3K4, H3K9 and H3K36, which also connected with the glucolipid metabolism.

Renal injury and hepatic effects from the methylimidazolium ionic liquid M8OI in mouse

The ionic liquid 1-octyl-3-methylimidazolium (M8OI) has been found in the environment and identified as a hazard for triggering the liver disease primary biliary cholangitis (PBC). Given limited toxicity data for M8OI and other structurally-related ionic liquids, target organs for M8OI toxicity were examined. Adult male C57Bl6 mice were acutely exposed to 0-10 mg/kg body weight M8OI via 2 intraperitoneal injections (time zero and 18 h) and effects examined at 24 h. At termination, tissue histopathology, serum and urinary endpoints were examined. No overt pathological changes were observed in the heart and brain. In contrast, focal and mild to multifocal and moderate degeneration with a general trend for an increase in severity with increased dose was observed in the kidney. These changes were accompanied by a dose-dependent increased expression of Kim1 in kidney tissue, marked elevations in urinary Kim1 protein and a dose-dependent increase in serum creatinine. Hepatic changes were limited to a significant dose-dependent loss of hepatic glycogen and a mild but significant increase in portal tract inflammatory recruitment and/or fibroblastic proliferation accompanied by a focal fibrotic change. Cultured mouse tissue slices reflected these in vivo effects in that dose-dependent injury was observed in kidney slices but not in the liver. Kidney slices accumulated higher levels of M8OI than liver slices (e.g. at 10 μM, greater than 4 fold) and liver slices where markedly more active in the metabolism of M8OI. These data indicate that the kidney is a target organ for the toxic effects of M8OI accompanied by mild cholangiopathic changes in the liver after intraperitoneal administration.

Emerging risk from "environmentally-friendly" solvents: Interaction of methylimidazolium ionic liquids with the mitochondrial electron transport chain is a key initiation event in their mammalian toxicity

Recent studies have identified the 8C alkyl chain methylimidazolium ionic liquid 1-octyl-3-methylimidazolium in the environment and its potential to trigger the auto-immune liver disease primary biliary cholangitis. The toxicity of a range of methylimidazolium ionic liquids were therefore examined. Oxygen consumption was rapidly inhibited, with potency increasing with alkyl chain length. This preceded caspase 3/7 induction and DNA fragmentation. Time- and dose-dependent loss of dye reduction capacities reflected these effects, with a >700 fold difference in potency between 2C and 10C alkyl chain liquids. None of the ionic liquids directly inhibited mitochondrial complexes I-IV or complex V (F₀F₁-ATPase). However, dithionite reduction and ESR spectroscopy studies indicate a one electron reduction of oxygen in the presence of a methylimidazolium ionic liquid, suggesting methylimidazolium ionic liquids function as mitochondrial electron acceptors. However, only longer chain ionic liquids form a non-aqueous phase or micelle under aqueous physiological conditions and lead to increases in reactive oxygen species in intact cells. These data therefore suggest that the longer chain methylimidazolium liquids are toxic in sensitive liver progenitor cells because they both readily integrate within the inner mitochondrial membrane and accept electrons from the electron chain, leading to oxidative stress.

Changes in the gut microbiota of mice orally exposed to methylimidazolium ionic liquids

Ionic liquids are salts used in a variety of industrial processes, and being relatively non-volatile, are proposed as environmentally-friendly replacements for existing volatile liquids. Methylimidazolium ionic liquids resist complete degradation in the environment, likely because the imidazolium moiety does not exist naturally in biological systems. However, there is limited data available regarding their mammalian effects in vivo. This study aimed to examine the effects of exposing mice separately to 2 different methylimidazolium ionic liquids (BMI and M8OI) through their addition to drinking water. Potential effects on key target organs-the liver and kidney-were examined, as well as the gut microbiome. Adult male mice were exposed to drinking water containing ionic liquids at a concentration of 440 mg/L for 18 weeks prior to examination of tissues, serum, urine and the gut microbiome. Histopathology was performed on tissues and clinical chemistry on serum for biomarkers of hepatic and renal injury. Bacterial DNA was isolated from the gut contents and subjected to targeted 16S rRNA sequencing. Mild hepatic and renal effects were limited to glycogen depletion and mild degenerative changes respectively. No hepatic or renal adverse effects were observed. In contrast, ionic liquid exposure altered gut microbial composition but not overall alpha diversity. Proportional abundance of Lachnospiraceae, Clostridia and Coriobacteriaceae spp. were significantly greater in ionic liquid-exposed mice, as were predicted KEGG functional pathways associated with xenobiotic and amino acid metabolism. Exposure to ionic liquids via drinking water therefore resulted in marked changes in the gut microbiome in mice prior to any overt pathological effects in target organs. Ionic liquids may be an emerging risk to health through their potential effects on the gut microbiome, which is implicated in the causes and/or severity of an array of chronic disease in humans.

Primary biliary cholangitis: pathogenesis and therapeutic opportunities

Primary biliary cholangitis is a chronic, seropositive and female-predominant inflammatory and cholestatic liver disease, which has a variable rate of progression towards biliary cirrhosis. Substantial progress has been made in patient risk stratification with the goal of personalized care, including early adoption of next-generation therapy with licensed use of obeticholic acid or off-label fibrate derivatives for those with insufficient benefit from ursodeoxycholic acid, the current first-line drug. The disease biology spans genetic risk, epigenetic changes, dysregulated mucosal immunity and altered biliary epithelial cell function, all of which interact and arise in the context of ill-defined environmental triggers. A current focus of research on nuclear receptor pathway modulation that specifically and potently improves biliary excretion, reduces inflammation and attenuates fibrosis is redefining therapy. Patients are benefiting from pharmacological agonists of farnesoid X receptor and peroxisome proliferator-activated receptors. Immunotherapy remains a challenge, with a lack of target definition, pleiotropic immune pathways and an interplay between hepatic immune responses and cholestasis, wherein bile acid-induced inflammation and fibrosis are dominant clinically. The management of patient symptoms, particularly pruritus, is a notable goal reflected in the development of rational therapy with apical sodium-dependent bile acid transporter inhibitors.

The toxicity of the methylimidazolium ionic liquids, with a focus on M8OI and hepatic effects

Ionic liquids are a diverse range of charged chemicals with low volatility and often liquids at ambient temperatures. This characteristic has in part lead to them being considered environmentally-friendly replacements for existing volatile solvents. However, methylimidazolium ionic liquids are slow to break down in the environment and a recent study at Newcastle detected 1 octyl 3 methylimidazolium (M8OI) - an 8 carbon variant methylimidazolium ionic liquid - in soils in close proximity to a landfill site. The current M8OI toxicity database in cultured mammalian cells, in experimental animal studies and in model indicators of environmental impact are reviewed. Selected analytical data from the Newcastle study suggest the soils in close proximity to the landfill site, an urban soil lacking overt contamination, had variable levels of M8OI. The potential for M8OI - or a structurally related ionic liquid - to trigger primary biliary cholangitis (PBC), an autoimmune liver disease thought to be triggered by an unknown agent(s) in the environment, is reviewed.

Abnormal Expression of ERα in Cholangiocytes of Patients With Primary Biliary Cholangitis Mediated Intrahepatic Bile Duct Inflammation

ERα, one of the classical receptors of estrogen, has been found to be abnormally up-regulated in patients with primary biliary cholangitis (PBC), which is an important factor leading to ductopenia. ERα-mediated signaling pathways are involved in proliferation of human intrahepatic biliary epithelial cells (HiBECs) and portal inflammation. Our previous studies have shown that the expression levels of ERα in the liver tissues of PBC patients are positively correlated with the levels of serum pro-inflammatory cytokines. The present study was designed to assess the relationship between abnormal ERα expression in small bile ducts and the progression of PBC. We examined the levels of multiple cytokines and analyzed their relationship with clinical parameters of livers functions in a cohort of 43 PBC patients and 45 healthy controls (HC). The levels of ERα expression and the relation with the levels of cytokines were further assessed. The localization of cytokines and ERα-mediated signaling pathways in liver were examined using immunohistochemistry. The possible underlying mechanisms of these alterations in PBC were explored in vitro. Our results demonstrated that the levels of IL-6, IL-8, and TNF-α were increased in PBC patients, and positively correlated with the serum AKP levels and ERα expression levels. Moreover, the expression of these cytokines were up-regulated in HiBECs that were stimulated with 17β-estradiol and PPT (an ERα agonist) and they also were positive in intrahepatic bile duct of PBC patients. The ERα-mediated expression of pro-inflammatory cytokines was induced by JNK, P38, and STAT3 phosphorylation in HiBECs. In addition, the CD54 expression was increased in HiBECs after ERα activation, which induced peripheral blood monouclear cells (PBMCs) recruitment. In conclusion, the present study highlighted a key role of abnormal ERα expression in inducing an inflammatory phenotype of HiBECs, which was critical in the development of inflammation and damage in small bile duct.