Butylated hydroxyanisole isomers induce distinct adipogenesis in 3T3-L1 cells

Gut dysbiosis contributes to SCFAs reduction-associated adipose tissue macrophage polarization in gestational diabetes mellitus

AIMS

The prevalence of gestational diabetes mellitus (GDM) has spurred investigations into various interconnected factors, among which gut dysbiosis is notably prominent. Although gut dysbiosis is strongly associated with GDM, the specific role of the gut microbiome in the pathogenesis of GDM remains unknown. This study aims to explore the pathogenesis of GDM from gut microbiota.

MATERIALS AND METHODS

In our study, we constructed two GDM mice models: one induced by a high-fat diet (HFD) and the other through fecal microbiota transplantation (FMT) from GDM patients. In vitro, we used a co-culture system of RAW264.7 and 3T3-L1 adipocytes.

KEY FINDINGS

We induced a GDM-like state in pregnant mice by FMT from GDM patients, which was consistent with the HFD model. A potential mechanism identified involves the diminished abundance of SCFA-producing microbiota, which reduces SCFAs, particularly propionic acid and butyric acid. In vitro, butyric and propionic acids were observed to alleviate LPS-induced TLR4-NF-κB activation, thereby reducing inflammation levels and inhibiting adipose insulin resistance via the PI3K/AKT signaling pathway. This reduction appears to trigger the polarization of adipose tissue macrophages toward M1 and promote insulin resistance in adipose tissue.

SIGNIFICANCE

Our study fills this knowledge gap by finding that alterations in gut microbiota have an independent impact on hyperglycemia and insulin resistance in the GDM state. In vivo and in vitro, gut dysbiosis is linked to adipose tissue inflammation and insulin resistance via the bacterial product SCFAs in the GDM state, providing new insights into the pathogenesis of GDM.

Assessment of the disruption effects of tetrabromobisphenol A and its analogues on lipid metabolism using multiple in vitro models

Tetrabromobisphenol A (TBBPA), a widely-used brominated flame retardant, has been revealed to exert endocrine disrupting effects and induce adipogenesis. Given the high structural similarities of TBBPA analogues and their increasing exposure risks, their effects on lipid metabolism are necessary to be explored. Herein, 9 representative TBBPA analogues were screened for their interference on 3T3-L1 preadipocyte adipogenesis, differentiation of C3H10T1/2 mesenchymal stem cells (MSCs) to brown adipocytes, and lipid accumulation of HepG2 cells. TBBPA bis(2-hydroxyethyl ether) (TBBPA-BHEE), TBBPA mono(2-hydroxyethyl ether) (TBBPA-MHEE), TBBPA bis(glycidyl ether) (TBBPA-BGE), and TBBPA mono(glycidyl ether) (TBBPA-MGE) were found to induce adipogenesis in 3T3-L1 preadipocytes to different extends, as evidenced by the upregulated intracellular lipid generation and expressions of adipogenesis-related biomarkers. TBBPA-BHEE exhibited a stronger obesogenic effect than did TBBPA. In contrast, the test chemicals had a weak impact on the differentiation process of C3H10T1/2 MSCs to brown adipocytes. As for hepatic lipid formation test, only TBBPA mono(allyl ether) (TBBPA-MAE) was found to significantly promote triglyceride (TG) accumulation in HepG2 cells, and the effective exposure concentration of the chemical under oleic acid (OA) co-exposure was lower than that without OA co-exposure. Collectively, TBBPA analogues may perturb lipid metabolism in multiple tissues, which varies with the test tissues. The findings highlight the potential health risks of this kind of emerging chemicals in inducing obesity, non-alcoholic fatty liver disease (NAFLD) and other lipid metabolism disorders, especially under the conditions in conjunction with high-fat diets.

Subchronic co-exposure of polystyrene nanoplastics and 3-BHA significantly aggravated the reproductive toxicity of ovaries and uterus in female mice

Both nanoplastics (NPs) and 3-tert-butyl-4-hydroxyanisole (3-BHA) are environmental contaminants that can bio-accumulate through the food chain. However, the combined effects of which on mammalian female reproductive system remain unclear. Here, the female ICR-CD1 mice were used to evaluate the damage effects of ovaries and uterus after NPs and 3-BHA co-treatment for 35 days. Firstly, co-exposure significantly reduced the body weight and organ index of ovaries and uterus in mice. Secondly, combined effects of NPs and 3-BHA exacerbated the histopathological abnormalities to the ovaries and uterus and decreased female sex hormones such as FSH and LH while increased antioxidant activities including CAT and GSH-Px. Moreover, the apoptotic genes, inflammatory cytokines and the key reproductive development genes such as FSTL1 were significantly up-regulated under co-exposure conditions. Thirdly, through transcriptional and bioinformatics analysis, immunofluorescence and western blotting assays, together with molecular docking simulation, we determined that co-exposure up-regulated the FSTL1, TGF-β and p-Smad1/5/9 but down-regulated the expression of BMP4. Finally, the pharmacological rescue experiments further demonstrated that co-exposure of NPs and 3-BHA mainly exacerbated the female reproductive toxicity through FSTL1-mediated BMP4/TGF-β/SMAD signaling pathway. Taken together, our studies provided the theoretical basis of new environmental pollutants on the reproductive health in female mammals.

A microneedle patch realizes weight loss through photothermal induction of fat browning

As a globally prevalent disease, obesity leads to many chronic diseases, so it is important to develop safe and effective treatments with fewer side effects and lasting weight loss. In this study, we developed a biodegradable hyaluronic acid microneedle patch loaded with polydopamine nanoparticles and mirabegron, which directly acted on subcutaneous white adipose tissue, and then induced browning of white adipose tissue through mild photothermal therapy. The approach showed excellent browning-promoting ability and biocompatibility. It is noteworthy that the weight of untreated mice increased by 9%, while the weight of obese mice decreased by nearly 19% after photothermal treatment. In addition, when mirabegron was used in combination with photothermal therapy, the weight loss of obese mice was more significant, with a weight loss of about 22%. This microneedle patch exhibited attractive potential for body slimming.

Degradation of Butylated Hydroxyanisole by the Combined Use of Peroxymonosulfate and Ferrate(VI): Reaction Kinetics, Mechanism and Toxicity Evaluation

Butylated hydroxyanisole (BHA), a synthetic phenolic antioxidant (SPA), is now widely present in natural waters. To improve the degradation efficiency of BHA and reduce product toxicity, a combination of peroxymonosulfate (PMS) and Ferrate(VI) (Fe(VI)) was used in this study. We systematically investigated the reaction kinetics, mechanism and product toxicity in the degradation of BHA through the combined use of PMS and Fe(VI). The results showed that PMS and Fe(VI) have synergistic effects on the degradation of BHA. The effects of operational factors, including PMS dosage, pH and coexisting ions (Cl-, SO42-, HCO3-, K+, NH4+ and Mg2+), and different water matrices were investigated through a series of kinetic experiments. When T = 25 °C, the initial pH was 8.0, the initial BHA concentration was 100 μM, the initial concentration ratio of [PMS]0:[Fe(VI)]0:[BHA]0 was 100:1:1 and the degradation rate could reach 92.4% within 30 min. Through liquid chromatography time-of-flight mass spectrometry (LC-TOF-MS) identification, it was determined that the oxidation pathway of BHA caused by PMS/Fe(VI) mainly includes hydroxylation, ring-opening and coupling reactions. Density functional theory (DFT) calculations indicated that •OH was most likely to attack BHA and generate hydroxylated products. The comprehensive comparison of product toxicity results showed that the PMS/Fe(VI) system can effectively reduce the environmental risk of a reaction. This study contributes to the development of PMS/Fe(VI) for water treatment applications.

Application of Ion Mobility Spectrometry and the Derived Collision Cross Section in the Analysis of Environmental Organic Micropollutants

Ion mobility spectrometry (IMS) is a rapid gas-phase separation technique, which can distinguish ions on the basis of their size, shape, and charge. The IMS-derived collision cross section (CCS) can serve as additional identification evidence for the screening of environmental organic micropollutants (OMPs). In this work, we summarize the published experimental CCS values of environmental OMPs, introduce the current CCS prediction tools, summarize the use of IMS and CCS in the analysis of environmental OMPs, and finally discussed the benefits of IMS and CCS in environmental analysis. An up-to-date CCS compendium for environmental contaminants was produced by combining CCS databases and data sets of particular types of environmental OMPs, including pesticides, drugs, mycotoxins, steroids, plastic additives, per- and polyfluoroalkyl substances (PFAS), polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs), as well as their well-known transformation products. A total of 9407 experimental CCS values from 4170 OMPs were retrieved from 23 publications, which contain both drift tube CCS in nitrogen (DTCCSN2) and traveling wave CCS in nitrogen (TWCCSN2). A selection of publicly accessible and in-house CCS prediction tools were also investigated; the chemical space covered by the training set and the quality of CCS measurements seem to be vital factors affecting the CCS prediction accuracy. Then, the applications of IMS and the derived CCS in the screening of various OMPs were summarized, and the benefits of IMS and CCS, including increased peak capacity, the elimination of interfering ions, the separation of isomers, and the reduction of false positives and false negatives, were discussed in detail. With the improvement of the resolving power of IMS and enhancements of experimental CCS databases, the practicability of IMS in the analysis of environmental OMPs will continue to improve.

A review of the occurrence, metabolites and health risks of butylated hydroxyanisole (BHA)

Butylated hydroxyanisole (BHA) is mainly used as a food additive due to its antioxidant properties, which prevent or delay oxidation reactions and extend the storage life of products. The widespread use of BHA has led to its extensive presence in various environmental matrices and human tissues. Food intake is the main route of human exposure to BHA. Under different conditions, BHA can produce different metabolites, with tert-butyl hydroquinone (TBHQ) being one of the major products. Several studies have shown that BHA could cause thyroid system damage, metabolic and growth disorders, neurotoxicity, and carcinogenesis. Mechanisms such as endocrine disruption, genotoxicity, disturbances of energy metabolism, reactive oxygen species (ROS) production, signaling pathways, and imbalances in calcium homeostasis appear to be associated with the toxic effects of BHA. Avoiding the toxic effects of BHA to the maximum extent possible is a top priority. Finding safe, non-toxic and environmentally friendly alternatives to BHA should be the focus of subsequent research. In all, this review summarized the current situation related to BHA and might make recommendations for future research directions. © 2023 Society of Chemical Industry.

3-tert-Butyl-4-hydroxyanisole Perturbs Differentiation of C3H10T1/2 Mesenchymal Stem Cells into Brown Adipocytes through Regulating Smad Signaling

3-tert-Butyl-4-hydroxyanisole (3-BHA), one of the most commonly used antioxidants in foodstuffs, has been identified as an environmental endocrine disruptor (EED) with obesogenic activity. Given the increasing concern on EED-caused dysfunction in lipid metabolism, whether 3-BHA could influence the development of brown adipocytes is worthy of being explored. In this study, the effect of 3-BHA on the differentiation of C3H10T1/2 mesenchymal stem cells (MSCs) into brown adipocytes was investigated. Exposure to 3-BHA promoted lipogenesis of the differentiated cells, as evidenced by the increased intracellular lipid accumulation and elevated expressions of adipogenic biomarkers, including peroxisome proliferator-activated receptor γ (PPARγ), Perilipin, Adiponectin, and fatty acid binding protein 4 (FABP4). Surprisingly, the thermogenic capacity of the differentiated cells was compromised as a result of 3-BHA exposure, because neither intracellular mitochondrial contents nor expressions of thermogenic biomarkers, including uncoupling protein 1 (UCP1), peroxisome proliferator-activated receptor γ coactivator 1α (PGC1α), cell-death-inducing DNA fragmentation factor α subunit-like effector A (CIDEA), and PR domain containing 16 (PRDM16), were increased by this chemical. The underlying molecular mechanism exploration revealed that, in contrast to p38 MAPK, 3-BHA stimulation induced phosphorylation of Smad1/5/8 in an exposure time-dependent manner, suggesting that this chemical-triggered Smad signaling was responsible for the shift of C3H10T1/2 MSC differentiation from a brown to white-like phenotype. The finding herein, for the first time, revealed the perturbation of 3-BHA in the development of brown adipocytes, uncovering new knowledge about the obesogenic potential of this emerging chemical of concern.

PPARγ As a Potential Target for Adipogenesis Induced by Fine Particulate Matter in 3T3-L1 Preadipocytes

Mounting evidence has shown that ambient PM_2.5 exposure is closely associated with the development of obesity, and adipose tissue represents an important endocrine target for PM_2.5. In this study, the 3T3-L1 preadipocyte differentiation model was employed to comprehensively explore the adipogenic potential of PM_2.5. After 8 days of PM_2.5 exposure, adipocyte fatty acid uptake and lipid accumulation were significantly increased, and adipogenic differentiation of 3T3-L1 cells was promoted in a concentration-dependent manner. Transcriptome and lipidome analyses revealed the systematic disruption of transcriptional and lipid profiling at 10 μg/mL PM_2.5. Functional enrichment and visualized network analyses showed that the peroxisome proliferator-activated receptor (PPAR) pathway and the metabolism of glycerophospholipids, glycerolipids, and sphingolipids were most significantly affected during adipocyte differentiation. Reporter gene assays indicated that PPARγ was activated by PM_2.5, demonstrating that PM_2.5 promoted adipogenesis by activating PPARγ. The increased transcriptional and protein expressions of PPARγ and downstream adipogenesis-associated markers (e.g., Fabp4 and CD36) were further cross-validated using qRT-PCR and western blot. PM_2.5-induced adipogenesis, PPARγ pathway activation, and lipid remodeling were significantly attenuated by the supplementation of a PPARγ antagonist (T0070907). Overall, this study yielded mechanistic insights into PM_2.5-induced adipogenesis in vitro by identifying the potential biomolecular targets for the prevention of PM_2.5-induced obesity and related metabolic diseases.

3-tert-Butyl-4-hydroxyanisole perturbs renal lipid metabolism in vitro by targeting androgen receptor-regulated de novo lipogenesis

The widespread usage of 3-tert-butyl-4-hydroxyanisole (3-BHA) as an anthropogenic antioxidant has caused considerable environmental contamination and frequent detection in diverse human-derived samples. 3-BHA can promote adipogenesis and impair hepatic lipid metabolism, while its effects on renal lipid homeostasis remain to be uncertain. Herein, using the human kidney 2 (HK-2) cell experiments, 3-BHA was found to cause a significant reduction in lipid accumulation of the HK-2 cells in both exposure concentration- and duration-dependent manners. Exposure to 3-BHA lowered the transcriptional expressions of sterol regulatory element-binding protein 1 (SREBP1) and acetyl-CoA carboxylase (ACC), as well as ACC activity, indicating the inhibition in the process of de novo lipogenesis in HK-2 cells. On this basis, the mechanism study suggested that the reduced glucose absorption and accelerated glycolysis were concomitantly involved. The antagonism of 3-BHA on the transactivation of androgen receptor (AR) contributed to the lowered de novo lipogenesis and the consequent intracellular lipid reduction. The metabolomics data further confirmed the imbalance of lipid homeostasis and dysregulation of de novo lipogenesis. The new findings on the impaired renal lipid metabolism induced by 3-BHA warranted proper care about the usage of this chemical as a food additive.

Pituitary Adenylate Cyclase-activating Polypeptide (PACAP) -derived Peptide MPAPO Stimulates Adipogenic Differentiation by Regulating the Early Stage of Adipogenesis and ERK Signaling Pathway

Regenerative medicine and tissue engineering have delivered new healing possibilities to the treatment of soft tissue defects, but the selection of seed cells is critical for treatment. Adipose-derived stem cells have perpetually been a preferred candidate for seed cells due to their wealthy sources, simple access, high plasticity, and powerful value-added capabilities. How to improve the efficiency of adipogenic differentiation is the key to the treatment. Pituitary adenylate cyclase-activating peptide, as a biologically active peptide secreted by the pituitary, is widely involved in regulating the body's sugar metabolism and lipid metabolism. However, the effects of MPAPO in ADSCs adipogenic differentiation remain unknown. Our results reveal that MPAPO treatment improves the adipogenic differentiation efficiency of ADSCs, including promoting the accumulation of lipid droplets and triglycerides, and the expression of adipocyte protein biomarkers PPARγ and C/EBPa. Additionally, the mechanism studies showed that the effective window of MPAPO-induced adipogenesis was the first 3 days during ADSCs differentiation. MPAPO selectively binds to the PAC1 receptor and promotes adipogenic differentiation of ADSCs by activating the ERK signaling pathway and elevating cell proliferation during postconfluent mitosis stage. Altogether, we demonstrate that MPAPO plays a crucial role in ADSCs adipogenesis, providing experimental basis and data for exploring therapeutic options in tissue defect repair.

Constructing an MCF-7 breast cancer cell-based transient transfection assay for screening RARα (Ant)agonistic activities of emerging phenolic compounds

The screening of compounds with endocrine disrupting effects has been attracting increasing attention due to the continuous release of emerging chemicals into the environment. Testing the (ant)agonistic activities of these chemicals on the retinoic acid receptor α (RARα), a vital nuclear receptor, is necessary to explain their perturbation in the endocrine system in vivo. In the present study, MCF-7 breast carcinoma cells were transiently transfected with a RARα expression vector (pEF1α-RARα-RFP) and a reporter vector containing a retinoic acid reaction element (pRARE-TA-Luc). Under optimized conditions, the performance of the newly constructed system was evaluated for its feasibility in screening the (ant)agonistic effects of emerging phenolic compounds on RARα. The results showed that this transient transfection cell model responded well to stimulation with (ant)agonists of RARα, and the EC₅₀ and IC₅₀ values were 0.87 nM and 2.67 μM for AM580 and Ro41-5253, respectively. Its application in testing several emerging phenolic compounds revealed that triclosan (TCS) and tetrabromobisphenol A (TBBPA) exerted notable RARα antagonistic activities. This newly developed bioassay based on MCF-7 is promising in identifying the agonistic or antagonistic activities of xenobiotics on RARα and has good potential for studying RARα signaling-involved toxicological effects of emerging chemicals of concern.

Occurrence of synthetic phenolic antioxidants in foodstuffs from ten provinces in China and its implications for human dietary exposure

Synthetic phenolic antioxidants (SPAs) are widely used as food additives to delay the oxidation rate of oils and oil products. The concentrations and compositions of SPAs in Chinese residents' most popular daily foods and the resulting exposure risk of SPAs are not clear. Therefore, this study collected food samples in 13 food categories (n = 289) from 10 provinces in China. At least one of the SPAs was detected in approximately 99.7% of foodstuffs, and the concentration of ∑SPAs ranged from not detected to 7830 (geometric mean (GM): 296 ng/g wet weight). 2,6-2 tert butyl p-1,4-benzoquinone (BHT-Q) was the main transformation product, but SPAs in food tend to exist in the parent form. A significant difference between food categories was analyzed. The highest GM of ΣSPAs occurred in cereals and cereal products, which was approximately 8 times higher than that in beverages. The estimated daily intakes of ΣSPAs in Chinese preschoolers, school-age children, adults and elderly individuals were 22200, 9970, 7540 and 7700 ng/kg bw/day, respectively. The exposure risks of SPAs decreased with age. This is the first simultaneous analysis of SPAs in multiple provinces and multiple categories of foodstuffs.

Obesogens in Foods

Obesogens, as environmental endocrine-disrupting chemicals, are supposed to have had an impact on the prevalence of rising obesity around the world over the last forty years. These chemicals are probably able to contribute not only to the development of obesity and metabolic disturbances in individuals, but also in their progeny, having the capability to epigenetically reprogram genetically inherited set-up points for body weight and body composition control during critical periods of development, such as fetal, early life, and puberty. In individuals, they may act on myriads of neuro-endocrine–immune metabolic regulatory pathways, leading to pathophysiological consequences in adipogenesis, lipogenesis, lipolysis, immunity, the influencing of central appetite and energy expenditure regulations, changes in gut microbiota–intestine functioning, and many other processes. Evidence-based medical data have recently brought much more convincing data about associations of particular chemicals and the probability of the raised risk of developing obesity. Foods are the main source of obesogens. Some obesogens occur naturally in food, but most are environmental chemicals, entering food as a foreign substance, whether in the form of contaminants or additives, and they are used in a large amount in highly processed food. This review article contributes to a better overview of obesogens, their occurrence in foods, and their impact on the human organism.

Obesity II: Establishing causal links between chemical exposures and obesity

Obesity is a multifactorial disease with both genetic and environmental components. The prevailing view is that obesity results from an imbalance between energy intake and expenditure caused by overeating and insufficient exercise. We describe another environmental element that can alter the balance between energy intake and energy expenditure: obesogens. Obesogens are a subset of environmental chemicals that act as endocrine disruptors affecting metabolic endpoints. The obesogen hypothesis posits that exposure to endocrine disruptors and other chemicals can alter the development and function of the adipose tissue, liver, pancreas, gastrointestinal tract, and brain, thus changing the set point for control of metabolism. Obesogens can determine how much food is needed to maintain homeostasis and thereby increase the susceptibility to obesity. The most sensitive time for obesogen action is in utero and early childhood, in part via epigenetic programming that can be transmitted to future generations. This review explores the evidence supporting the obesogen hypothesis and highlights knowledge gaps that have prevented widespread acceptance as a contributor to the obesity pandemic. Critically, the obesogen hypothesis changes the narrative from curing obesity to preventing obesity.

Environmental pollution, a hidden culprit for health issues

The environmental and health impacts from the massive discharge of chemicals and subsequent pollution have been gaining increasing public concern. The unintended exposure to different pollutants, such as heavy metals, air pollutants and organic chemicals, may cause diverse deleterious effects on human bodies, resulting in the incidence and progression of different diseases. The article reviewed the outbreak of environmental pollution-related public health emergencies, the epidemiological evidence on certain pollution-correlated health effects, and the pathological studies on specific pollutant exposure. By recalling the notable historical life-threatening disasters incurred by local chemical pollution, the damning evidence was presented to criminate certain pollutants as the main culprit for the given health issues. The epidemiological data on the prevalence of some common diseases revealed a variety of environmental pollutants to blame, such as endocrine-disrupting chemicals (EDCs), fine particulate matters (PMs) and heavy metals. The retrospection of toxicological studies provided illustrative clues for evaluating ambient pollutant-induced health risks. Overall, environmental pollution, as the hidden culprit, should answer for the increasing public health burden, and more efforts are highly encouraged to strive to explore the cause-and-effect relationships through extensive epidemiological and pathological studies.

3-tert-Butyl-4-hydroxyanisole Impairs Hepatic Lipid Metabolism in Male Mice Fed with a High-Fat Diet

3-tert-Butyl-4-hydroxyanisole (3-BHA), one of the widely used food antioxidants, has been found to act as a potential obesogen by promoting adipogenesis in vitro and inducing white adipose tissue development in vivo. Whether 3-BHA-induced visceral obesity was accompanied by a disruption of hepatic lipid homeostasis in mammals remained unclear. In this study, we evaluated the effect of 3-BHA on the development of nonalcoholic fatty liver disease (NAFLD) in male C57BL/6J mice. After 18 weeks of oral administration of 10 mg/kg 3-BHA, the mice fed with a high-fat diet (HFD) had higher hepatic triglyceride concentrations (0.32 mg/mg protein) and severer steatosis (1.57 for the NAFLD score) than the control ones. The in vivo hepatic lipid deposition disturbed by 3-BHA was transcriptionally regulated by the genes involved in lipid uptake, de novo lipogenesis, fatty acid oxidation, and lipid export. The in vitro studies further confirmed that 24 h of exposure to 50 μM 3-BHA could induce intracellular oleic acid (OA) uptake and triglyceride accumulation (1.5-fold of the OA control) in HepG2 cells. Lipidomic analysis indicated the perturbation of 3-BHA in the levels of 30 lipid species related to sphingolipids, glycerophospholipids, and glycerolipids under HFD conditions. The findings herein first revealed the disruption effect of 3-BHA on hepatic lipid homeostasis, thus exacerbating the development of HFD-induced NAFLD.

Trace analysis of multiple synthetic phenolic antioxidants in foods by liquid chromatography-tandem mass spectrometry with complementary use of electrospray ionization and atmospheric pressure chemical ionization

This study presented a universal LC-MS/MS method for trace analysis of multiple synthetic phenolic antioxidants (SPAs) in foods by complementary use of electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI). The analytes included not only the well-known BHT and BHA but also 18 high molecular weight SPAs. The method utilized APCI to achieve sensitive analysis of BHT, Irganox 1010, Irganox 330, and Irganox 3125 based on the finding that APCI significantly improved the sensitivity of these weakly acidic or slightly polar SPAs, and utilized ESI to obtain sensitive analysis of other SPAs. Additionally, the method avoided background contamination by using effective measures including installation of a trapping column in the LC system. Method performance assessment showed satisfactory sensitivity, linearity, accuracy, and precision for analysis of SPAs in vegetable oil, milk powder, and baby fruit puree. Method application revealed widespread contamination of foods with BHT, Irganox 1010, and Irganox 1076.

Analysis, occurrence, toxicity and environmental health risks of synthetic phenolic antioxidants: A review

The continuous improvement of living standards is related to higher requirements for the freshness and taste of food. For example, synthetic phenolic antioxidants (SPAs) are added to fats and fried foods as food additives to minimize the oxidative rancidity of oils and fats. Hence, the global use of SPAs is increasing year by year. Dibutyl hydroxytoluene is one of the widely used SPAs, often in combination with butyl hydroxyanisole or gallate SPAs. The extensive use of these compounds makes them and their transformation products to be widespread in various environmental matrices, including indoor dust, wastewater, river water, sewage sludge, and sediment, as well as human samples, such as nails and urine, at concentrations varying from nanogram per gram (ng/g) to microgram per gram (μg/g). Animal experiments have shown that high-dose SPA exposure is toxic, which may lead to DNA damage and mismatches and the development of cancerous tumors. Since the biosphere shares the same set of genetic codes, humans and animals have many identical or similar feedback mechanisms and information pathways. Therefore, the damage of SPAs to animals may also threaten human health. This review discusses the properties, occurrence, analysis, and environmental health risks of typical SPAs, including butyl hydroxyanisole, dibutyl hydroxytoluene, tert-butylhydroquinone, propyl gallate, octyl gallate, and lauryl gallate, used as food additives. In addition, AO2246, which is used in food packaging bags, is also considered. Future research directions on SPAs and their transformation products (TPs) are identified and discussed.

Supplementing rabbit diets with butylated hydroxyanisole affects oxidative stress, growth performance, and meat quality

Butylated hydroxyanisole (BHA) is a synthetic antioxidant analogous of vitamin E. It is used as a preservative to prevent free radical-mediated oxidation in high-fat foods, and this study's objective was to investigate the effects of BHA on oxidative stress and apoptosis in addition to delineating its efficacy as a growth-promoting feed additive. 60 weaned male rabbits (V-line) were randomly divided into four equal groups: BHA0.0 (control), BHA50, BHA100, and BHA150, administered basal diets with 0.0, 50, 100, and 150 mg BHA/kg of feed for 60 days. Animals were examined for growth performance, markers of oxidative stress and apoptosis, and meat characteristics. Compared to the control group, rabbits receiving BHA-supplemented diets exhibited increases in BW and average daily gain (P < 0.01), where BHA50 and BHA100 groups showed increased muscle content of methionine aspartic acid, serine, and glutamine (P < 0.05). These two groups also exhibited elevated catalase and superoxide dismutase activities and diminished malondialdehyde levels in the liver. Butylated hydroxyanisole upregulated fatty acid synthase gene (FASN), especially in BHA100 animals. Bcl-2-associated X/B-celllymphoma-2 (Bax/Bcl-2) ratio significantly increased in animals receiving higher doses of BHA, and the weight of the liver significantly increased following BHA treatment. Supplementing growing rabbits with lower doses of dietary BHA may promote growth performance and meat quality via maintaining the redox balance. Hence, the 50-100 mg/kg may be recommended as a safe and still effective feed additive as well as an oxidative stress attenuator.

The new kids on the block: Emerging obesogens

The current obesity epidemic is calling for action in the determination of contributing factors. Although social and life-style factors have been traditionally associated with metabolic disruption, a subset of endocrine-disrupting chemicals (EDCs), called obesogens are garnering increasing attention for their ability to promote adipose tissue differentiation and accumulation. For some chemicals, such as tributyltin, there is conclusive evidence regarding their ability to promote adipogenesis and their mechanism of action. In recent years, the list of chemicals that exert obesogenic potential is increasing. In this chapter, we review current knowledge of the most recent developments in the field of emerging obesogens with a specific focus on food additives, surfactants, and sunscreens, for which the mechanism of action remains unclear. We also review new evidence relative to the obesogenic potential of environmentally relevant chemical mixtures and point to potential therapeutic approaches to minimize the detrimental effects of obesogens. We conclude by discussing the available tools to investigate new obesogenic chemicals, strategies to maximize reproducibility in adipogenic studies, and future directions that will help propel the field forward.

Exploring the mode of binding between butylated hydroxyanisole with bovine serum albumin: Multispectroscopic and molecular docking study

Considering the harm of BHA on humans, thorough research of the effect of BHA on the structure of serum albumin is necessary. The binding mechanisms of BHA with bovine serum albumin (BSA) and the effects of other three food additives (butylated hydroxytoluene, benzoic acid and citric acid) on BHA-BSA system were researched by multispectroscopy and molecular docking. The fluorescence quenching experiment results showed that the fluorescence quenching mechanism of BSA by BHA was static quenching. The binding constant ((5.70 ± 0.38) × 103 M-1 at 298 K) and thermodynamic parameters (ΔH = 110.8 ± 2.91 kJ·mol-1 and ΔS = 443.3 ± 9.30 J·mol-1·K-1) indicated that BHA and BSA formed a relatively stable complex through hydrophobic interaction. Three-dimensional fluorescence spectra confirmed the conformation changes of BSA due to the binding of BHA. Site marker competitive experiments and molecular docking proved that BHA could bind BSA into site I in subdomain IIA. The results of molecular docking showed that BHA formed hydrophobic interactions with amino acid residues (Ala290, Leu237, Leu259, Ile263 and Ile289). The presence of other food additives weakened the binding of BHA to BSA.

N-acetyl cysteine induces quiescent-like pancreatic stellate cells from an active state and attenuates cancer-stroma interactions

BACKGROUND

Pancreatic stellate cells (PSCs) occupy the majority of the pancreatic cancer microenvironment, contributing to aggressive behavior of pancreatic cancer cells (PCCs). Recently, anti-fibrotic agents have proven to be an effective strategy against cancer, but clinical trials have shown little efficacy, and the driving mechanism remains unknown. N-acetyl-cysteine (NAC) is often used for pulmonary cystic fibrosis. Pioglitazone, an agonist of peroxisome proliferator-activated receptor gamma, was habitually used for type II diabetes, but recently reported to inhibit metastasis of PCCs. However, few studies have focused on the effects of these two agents on cancer-stromal interactions.

METHOD

We evaluated the expression of α-smooth muscle actin (α-SMA) and the number of lipid droplets in PSCs cultured with or without NAC. We also evaluated changes in invasiveness, viability, and oxidative level in PSCs and PCCs after NAC treatment. Using an indirect co-culture system, we investigated changes in viability, invasiveness, and migration of PSCs and PCCs. Combined treatment effects of NAC and Pioglitazone were evaluated in PSCs and PCCs. In vivo, we co-transplanted KPC-derived organoids and PSCs to evaluate the effects of NAC and Pioglitazone's combination therapy on subcutaneous tumor formation and splenic xenografted mouse models.

RESULTS

In vitro, NAC inhibited the viability, invasiveness, and migration of PSCs at a low concentration, but not those of PCCs. NAC treatment significantly reduced oxidative stress level and expression of α-SMA, collagen type I in PSCs, which apparently present a quiescent-like state with a high number of lipid droplets. Co-cultured PSCs and PCCs mutually promoted the viability, invasiveness, and migration of each other. However, these promotion effects were attenuated by NAC treatment. Pioglitazone maintained the NAC-induced quiescent-like state of PSCs, which were reactivated by PCC-supernatant, and enhanced chemosensitivity of PCCs. In vivo, NAC and Pioglitazone's combination suppressed tumor growth and liver metastasis with fewer stromal components and oxidative stress level.

CONCLUSION

NAC suppressed activated PSCs and attenuated cancer-stromal interactions. NAC induces quiescent-like PSCs that were maintained in this state by pioglitazone treatment.

Active Polypropylene-Based Films Incorporating Combined Antioxidants and Antimicrobials: Preparation and Characterization

Development of polypropylene (PP) films incorporating antioxidant-antimicrobial agents can inhibit microbial growth and reduce undesirable deteriorating reactions and can preserve the quality of food. This study was aimed to use a combination of sorbic acid (SA), butylated hydroxyanisole (BHA), and butylated hydroxytoluene (BHT) to provide a synergistic effect at their reduced concentrations. A Combination of the additives was more effective in enhancing mechanical properties compared to their single state in film composition. The PP-2%SA-3%BHA film (T₃) had the highest tensile strength (17.9 MPa) and the lowest elongation at break (7.1%) than other films. The fourier-transform infrared (FTIR) proposed physical mixing of active additives within PP-matrix. Scanning electron microscopy showed uniform dispersion of the additives in PP-2%SA-1%BHT-1%BHA film (T₄) compared to others. BHT containing films decreased the storage and loss moduli leading to weakening of film viscoelastic behaviour and reducing film melting point. The prepared active films showed higher antioxidant activity than control PP-film following an order of T₄ > T₂ > T₃ corresponding to DPPH radical scavenging values of 89.1, 83.4 and 79.1%, respectively. All active films inhibited gram-negative and gram-positive bacteria growth. The results of this study indicated that the prepared active films possess desirable mechanical, thermal, antioxidant and antimicrobial properties enabling their use in food packaging.

Synthetic phenolic antioxidants: Metabolism, hazards and mechanism of action

Synthetic phenolic antioxidants can interact with peroxides produced by food. This paper reviews correlation between BHA, BHT and TBHQ metabolism and harms they cause and provides a theoretical basis for rational use of BHA, BHT and TBHQ in food, and also put some attention on the transformation and metabolic products of PG. We introduce BHA, BHT, TBHQ, PG and their possible metabolic pathways, and discuss possible harms and their specific mechanisms responsible. Excessive addition or incorrect use of synthetic phenolic antioxidants results in carcinogenicity, cytotoxicity, oxidative stress induction and endocrine disrupting effects, which warrant attention. BHA carcinogenicity is related to production of metabolites TBHQ and TQ, and cytotoxic effect of BHA is the main cause of apoptosis induction. BHT carcinogenicity depends on DNA damage degree, and tumour promotion is mainly related to production of quinone methylation metabolites. TBHQ carcinogenicity is related to induction of metabolite TQ and enzyme CYP1A1.

Obesity and endocrine-disrupting chemicals

Obesity is now a worldwide pandemic. The usual explanation given for the prevalence of obesity is that it results from consumption of a calorie dense diet coupled with physical inactivity. However, this model inadequately explains rising obesity in adults and in children over the past few decades, indicating that other factors must be important contributors. An endocrine-disrupting chemical (EDC) is an exogenous chemical, or mixture that interferes with any aspect of hormone action. EDCs have become pervasive in our environment, allowing humans to be exposed daily through ingestion, inhalation, and direct dermal contact. Exposure to EDCs has been causally linked with obesity in model organisms and associated with obesity occurrence in humans. Obesogens promote adipogenesis and obesity, in vivo, by a variety of mechanisms. The environmental obesogen model holds that exposure to obesogens elicits a predisposition to obesity and that such exposures may be an important yet overlooked factor in the obesity pandemic. Effects produced by EDCs and obesogen exposure may be passed to subsequent, unexposed generations. This "generational toxicology" is not currently factored into risk assessment by regulators but may be another important factor in the obesity pandemic as well as in the worldwide increases in the incidence of noncommunicable diseases that plague populations everywhere. This review addresses the current evidence on how obesogens affect body mass, discusses long-known chemicals that have been more recently identified as obesogens, and how the accumulated knowledge can help identify EDCs hazards.

4-Hexylphenol influences adipogenic differentiation and hepatic lipid accumulation in vitro

Finding the potential environmental obesogens is crucial to explain the prevalence of obesity and the related pathologies. Increasing evidence has showed that many chemicals with endocrine disrupting effects can disturb lipid metabolism. Whether 4-hexylphenol (4-HP), a widely-used surfactant and a potential endocrine disrupting chemical (EDC), is associated to influence adipogenesis and hepatic lipid accumulation remained to be elucidated. In this study, both the 3T3-L1 differentiation model and oleic acid (OA)-treated HepG2 cells were used to investigate the effects of 4-HP on lipid metabolism, and the underlying estrogen receptor (ER)-involved mechanism was explored using MVLN assay, molecular docking simulation and the antagonist test. The results based on lipid droplet staining and triglyceride accumulation assay showed that 4-HP treatment promoted the adipogenic differentiation of 3T3-L1 cells and increased hepatic cellular OA accumulation in exposure concentration-dependent manners. The study on the elaborated transcription networks indicated that 4-HP activated peroxisome proliferator-activated receptor γ (PPARγ) as well as the subsequent adipogenic gene program in 3T3-L1 cells. This chemical also induced the increase of OA uptake and decreases of de novo lipogenesis and fatty acid oxidation in HepG2 cells. The agonistic activity of 4-HP in triggering ER-mediated pathway was shown to correlate with its perturbation in lipid metabolism, as evidenced by the enhanced development of mature lipid-laden adipocytes and suppression of excessive hepatic lipid accumulation upon its co-treatment with ER antagonist. Altogether, these findings provide new insights into the potential health impacts of 4-HP exposure as it may relate to obesity and nonalcoholic fatty liver disease.

Obesogens: How They Are Identified and Molecular Mechanisms Underlying Their Action

Adult and childhood obesity have reached pandemic level proportions. The idea that caloric excess and insufficient levels of physical activity leads to obesity is a commonly accepted answer for unwanted weight gain. This paradigm offers an inconclusive explanation as the world continually moves towards an unhealthier and heavier existence irrespective of energy balance. Endocrine disrupting chemicals (EDCs) are chemicals that resemble natural hormones and disrupt endocrine function by interfering with the body's endogenous hormones. A subset of EDCs called obesogens have been found to cause metabolic disruptions such as increased fat storage, in vivo. Obesogens act on the metabolic system through multiple avenues and have been found to affect the homeostasis of a variety of systems such as the gut microbiome and adipose tissue functioning. Obesogenic compounds have been shown to cause metabolic disturbances later in life that can even pass into multiple future generations, post exposure. The rising rates of obesity and related metabolic disease are demanding increasing attention on chemical screening efforts and worldwide preventative strategies to keep the public and future generations safe. This review addresses the most current findings on known obesogens and their effects on the metabolic system, the mechanisms of action through which they act upon, and the screening efforts through which they were identified with. The interplay between obesogens, brown adipose tissue, and the gut microbiome are major topics that will be covered.

Identification of In Vitro Metabolites of Synthetic Phenolic Antioxidants BHT, BHA, and TBHQ by LC-HRMS/MS

Butylated hydroxytoluene (BHT) and its analogs, butylated hydroxyanisole (BHA) and tert-butyl-hydroquinone (TBHQ), are widely used synthetic preservatives to inhibit lipid oxidation in the food, cosmetic and pharmaceutical industries. Despite their widespread use, little is known about their human exposure and related biotransformation products. The metabolism of these compounds was investigated using in vitro incubations with human and rat liver fractions. Liquid chromatography coupled to high-resolution tandem mass spectrometry was employed to detect and characterize stable and reactive species formed via oxidative metabolism, as well as phase II conjugates. Several oxidative metabolites have been detected, as well as glutathione, glucuronide, and sulfate conjugates, many of which were not previously reported. A combination of accurate mass measurements, MS/MS fragmentation behavior, and isotope-labeling studies were used to elucidate metabolite structures.

Synthetic Phenolic Antioxidants: A Review of Environmental Occurrence, Fate, Human Exposure, and Toxicity

Synthetic phenolic antioxidants (SPAs) are widely used in various industrial and commercial products to retard oxidative reactions and lengthen product shelf life. In recent years, numerous studies have been conducted on the environmental occurrence, human exposure, and toxicity of SPAs. Here, we summarize the current understanding of these issues and provide recommendations for future research directions. SPAs have been detected in various environmental matrices including indoor dust, outdoor air particulates, sea sediment, and river water. Recent studies have also observed the occurrence of SPAs, such as 2,6-di-tert-butyl-4-methylphenol (BHT) and 2,4-di-tert-butyl-phenol (DBP), in humans (fat tissues, serum, urine, breast milk, and fingernails). In addition to these parent compounds, some transformation products have also been detected both in the environment and in humans. Human exposure pathways include food intake, dust ingestion, and use of personal care products. For breastfeeding infants, breast milk may be an important exposure pathway. Toxicity studies suggest some SPAs may cause hepatic toxicity, have endocrine disrupting effects, or even be carcinogenic. The toxicity effects of some transformation products are likely worse than those of the parent compound. For example, 2,6-di-tert-butyl-p-benzoquinone (BHT-Q) can cause DNA damage at low concentrations. Future studies should investigate the contamination and environmental behaviors of novel high molecular weight SPAs, toxicity effects of coexposure to several SPAs, and toxicity effects on infants. Future studies should also develop novel SPAs with low toxicity and low migration ability, decreasing the potential for environmental pollution.

Chemical Structure-Related Adipogenic Effects of Tetrabromobisphenol A and Its Analogues on 3T3-L1 Preadipocytes

Tetrabromobisphenol A (TBBPA), the most widely used brominated flame retardant, is reported to potentially possess risks in inducing obesity or obesity-related metabolic diseases. Considering the increasing environmental contamination of TBBPA analogues and their high structural similarities to the parent compound, whether they could influence adipogenesis or not remains to be elucidated. In this study, two of the most prevalent TBBPA derivatives [i.e., TBBPA bis(allyl ether) (TBBPA-BAE) and TBBPA bis(2,3-dibromopropyl ether) (TBBPA-BDBPE)] and their byproducts [i.e., TBBPA mono(allyl ether) (TBBPA-MAE) and TBBPA mono(2,3-dibromopropyl ether) (TBBPA-MDBPE)], together with TBBPA, were screened for their capacities in activating peroxisome proliferator-activated receptor-γ (PPARγ) and glucocorticoid receptor (GR), the key nuclear receptors involved in adipogenesis, and their structure-related effects on differentiation of 3T3-L1 preadipocytes were explored. The results indicated that the binding affinities of TBBPA and its analogues for the PPARγ ligand-binding domain (PPARγ-LBD) and GR, as well as their effects on PPARγ transactivation, followed the order of TBBPA > TBBPA-MAE > TBBPA-MDBPE > TBBPA-BAE, TBBPA-BDBPE. Nevertheless, TBBPA-MAE and TBBPA-MDBPE showed higher potentials in promoting adipogenesis in 3T3-L1 cells than did TBBPA, as evidenced by intracellular triglyceride contents and adipogenic biomarkers at both protein and transcriptional levels. The etherified group at position 4 of TBBPA phenolic rings was crucial in chemical-induced adipogenic effects, which was related with the recruitment of PPARγ and GR-mediated networks and some other unidentified signaling pathways. The findings on the disturbance of TBBPA analogues on adipogenesis revealed their potential risk in causing obesity and other lipid metabolism-related human health concerns.

Involvement of tumor necrosis factor-α, interferon gamma-γ, and interleukins 1β, 6, and 10 in immunosuppression due to long-term exposure to five common food preservatives in rats

BACKGROUND/AIMS

Food preservatives are abundant in many products in the human environment. However, little is known about the impact of many food preservatives on the immune system and the immune related genes. Hence, this study aimed to evaluate the effects of five widespread food preservatives, including butylated hydroxyanisole (BHA), potassium sorbate (PS), sodium benzoate (SB), boric acid (BA), and calcium propionate (CP), on haemato-immune functions.

METHOD

Sixty Sprague-Dawley rats were assigned to groups orally administered water (control), BHA (0.09 mg/kg), PS (4.5 mg/kg), SB (0.9 mg/kg), BA (0.16 mg/kg) or CP (0.18 mg/kg) for 90 consecutive days. Leukogram and erythrogram profiles were assessed. Nitric oxide and immunoglobulin levels together with phagocytic and lysozyme activities were estimated. Histologic examinations and histomorphometric analysis of splenic tissues were performed. Variations in the mRNA expression levels of tumour necrosis factor alpha (TNF-α), interferon gamma (IFNγ), interleukin (IL)-1β, IL-6, and IL-10 were assessed.

RESULTS

Anemic conditions, thrombocytopenia, leucocytopaenia simultaneous with lymphocytopaenia, monocytopenia, and esinopenia have been obvious following long term exposure to the tested food additives. Prominent exhaustion was noted in immunoglobulin and NO levels and in lysozyme and phagocytic activities. IFNγ, TNF-α, IL-1β, IL-6, and IL-10 were obviously upregulated in the groups exposed to food preservatives.

CONCLUSION

These results confirmed that continued exposure to high levels of BHA, PS, SB, BA, and CP has haematotoxic and immunotoxic effects. Furthermore, these adverse effects are mediated by cytokine production.

Environmental Obesogens and Their Impact on Susceptibility to Obesity: New Mechanisms and Chemicals

The incidence of obesity has reached an all-time high, and this increase is observed worldwide. There is a growing need to understand all the factors that contribute to obesity to effectively treat and prevent it and associated comorbidities. The obesogen hypothesis proposes that there are chemicals in our environment termed obesogens that can affect individual susceptibility to obesity and thus help explain the recent large increases in obesity. This review discusses current advances in our understanding of how obesogens act to affect health and obesity susceptibility. Newly discovered obesogens and potential obesogens are discussed, together with future directions for research that may help to reduce the impact of these pervasive chemicals.

Perturbation of 3-tert-butyl-4-hydroxyanisole in adipogenesis of male mice with normal and high fat diets

As one of the widely used anthropogenic food additives, 3-tert-butyl-4-hydroxyanisole (3-BHA) has been found to perturb adipogenesis in vitro and induce lipid accumulation in some strains of oleaginous microalgae. The impact of this chemical on adipocyte development and lipid metabolism in mammals remains to be elucidated. In this study, we performed 18-week oral administration of 3-BHA to male C57BL/6J mice with normal diet (ND) or high-fat diet (HFD) and investigated its impacts on adipogenesis and lipid accumulation in vivo. The results indicated that long-term exposure to 3-BHA impacted the mouse body weight gain, white adipose tissue accumulation, and plasma lipids through transcriptional regulation of adipogenesis, lipid metabolism, and adipocyte endocrine function, while glucose metabolism and insulin sensitivity remained unaffected. HFD-fed mice responded to 3-BHA stimulation differently from ND-fed animals, suggesting potential risks for the human burden of 3-BHA in lean and obese subjects. The findings herein validate 3-BHA as an environmental obesogen, and more caution is recommended for its authorized use as a food antioxidant against lipid rancidity.