Acrylamide: review of toxicity data and dose-response analyses for cancer and noncancer effects

Mitigation of acrylamide in fried food systems using a combination of zein-pectin hydrocolloid complex and a food-grade l-asparaginase

Acrylamide, a Maillard reaction product, formed in fried food poses a serious concern to food safety due to its neurotoxic and carcinogenic nature. A "Green Approach" using L-Asparaginase enzyme from GRAS-status bacteria synergized with hydrocolloid protective coating could be effective in inhibiting acrylamide formation. To fill this void, the present study reports a new variant of type-II L-asparaginase (AsnLb) from Levilactobacillus brevis NKN55, a food-grade bacterium isolated using a unique metabolite profiling approach. The recombinant AsnLb enzyme was characterized to study acrylamide inhibition ability and showed excellent specificity towards L-asparagine (157.2 U/mg) with Km, Vmax of 0.833 mM, 4.12 mM/min respectively. Pretreatment of potato slices with AsnLb (60 IU/mL) followed by zein-pectin nanocomplex led to >70% reduction of acrylamide formation suggesting synergistic effect of this dual component system. The developed strategy can be employed as a sustainable treatment method by food industries for alleviating acrylamide formation and associated health hazard in fried foods.

Dietary Exposure to Acrylamide Has Negative Effects on the Gastrointestinal Tract: A Review

Changing eating habits and an increase in consumption of thermally processed products have increased the risk of the harmful impact of chemical substances in food on consumer health. A 2002 report by the Swedish National Food Administration and scientists at Stockholm University on the formation of acrylamide in food products during frying, baking and grilling contributed to an increase in scientific interest in the subject. Acrylamide is a product of Maillard's reaction, which is a non-enzymatic chemical reaction between reducing sugars and amino acids that takes place during thermal processing. The research conducted over the past 20 years has shown that consumption of acrylamide-containing products leads to disorders in human and animal organisms. The gastrointestinal tract is a complex regulatory system that determines the transport, grinding, and mixing of food, secretion of digestive juices, blood flow, growth and differentiation of tissues, and their protection. As the main route of acrylamide absorption from food, it is directly exposed to the harmful effects of acrylamide and its metabolite-glycidamide. Despite numerous studies on the effect of acrylamide on the digestive tract, no comprehensive analysis of the impact of this compound on the morphology, innervation, and secretory functions of the digestive system has been made so far. Acrylamide present in food products modifies the intestine morphology and the activity of intestinal enzymes, disrupts enteric nervous system function, affects the gut microbiome, and increases apoptosis, leading to gastrointestinal tract dysfunction. It has also been demonstrated that it interacts with other substances in food in the intestines, which increases its toxicity. This paper summarises the current knowledge of the impact of acrylamide on the gastrointestinal tract, including the enteric nervous system, and refers to strategies aimed at reducing its toxic effect.

Metabolomic modelling and neuroprotective effects of carvacrol against acrylamide toxicity in rat's brain and sciatic nerve

The study aimed to investigate the harmful effects of acrylamide (AA), which forms in carbohydrate-rich foods at temperatures above 120°C, on the central and peripheral nervous systems and to evaluate the potential neuroprotective effects of carvacrol (CRV). Male Wistar Albino rats were subjected to AA (40 mg/kg/bw/day) and CRV (50 mg/kg/bw/day) for 15 days. Following the last administration, evaluations revealed disrupted gait, heightened thermal sensitivity and altered paw withdrawal thresholds in AA-exposed rats. Notably, AA reduced glutathione (GSH) and raised malondialdehyde (MDA) levels in both brain and sciatic nerve tissues. AA raised nuclear factor erythroid 2-related factor 2 (Nrf2), caspase 3 and nuclear factor κB (NF-κB) gene expressions while decreasing NR4A2. CRV co-administration mitigated gait abnormalities, elevated GSH levels and lowered MDA levels in both tissues. CRV also modulated gene expression, reducing Nrf2 and NF-κB while increasing NR4A2. Histopathological signs of AA-induced neurodegeneration and elevated glial fibrillary acidic protein levels observed in brain and sciatic nerve tissues were rectified with simultaneous administration of CRV, thereby demonstrating neuroprotective efficacy in both regions. This study is pioneering in demonstrating CRV's neuroprotective potential against AA-induced neurotoxicity in both central and peripheral nervous systems, effectively addressing limitations in the literature. In conclusion, the study revealed AA-induced neurodegeneration in the brain and sciatic nerve, with CRV significantly mitigating this neurotoxicity. This novel research underscores CRV's promise as a neuroprotective agent against AA-induced adverse effects in both the central and peripheral nervous systems.

Evaluation of the efficiency of thermostable L-asparaginase from B. licheniformis UDS-5 for acrylamide mitigation during preparation of French fries

A thermostable L-asparaginase was produced from Bacillus licheniformis UDS-5 (GenBank accession number, OP117154). The production conditions were optimized by the Plackett Burman method, followed by the Box Behnken method, where the enzyme production was enhanced up to fourfold. It secreted L-asparaginase optimally in the medium, pH 7, containing 0.5% (w/v) peptone, 1% (w/v) sodium chloride, 0.15% (w/v) beef extract, 0.15% (w/v) yeast extract, 3% (w/v) L-asparagine at 50 °C for 96 h. The enzyme, with a molecular weight of 85 kDa, was purified by ion exchange chromatography and size exclusion chromatography with better purification fold and percent yield. It displayed optimal catalysis at 70 °C in 20 mM Tris-Cl buffer, pH 8. The purified enzyme also exhibited significant salt tolerance too, making it a suitable candidate for the food application. The L-asparaginase was employed at different doses to evaluate its ability to mitigate acrylamide, while preparing French fries without any prior treatment. The salient attributes of B. licheniformis UDS-5 L-asparaginase, such as greater thermal stability, salt stability and acrylamide reduction in starchy foods, highlights its possible application in the food industry.

Maternal acrylamide exposure changes intestinal epithelium, immunolocalization of leptin and ghrelin and their receptors, and gut barrier in weaned offspring

Acrylamide (ACR) is an amide formed as a byproduct in many heat-processed starchy-rich foods. In utero ACR exposure has been associated with restricted fetal growth, but its effects of postnatal functional development of small intestine is completely unknown. The current study investigated the time- and segment-dependent effects of prenatal ACR exposure on morphological and functional development of small intestine in weaned rat offspring. Four groups of pregnant female Wistar rats were exposed to ACR (3 mg/kg b.w./day) for 0, 5, 10 and 15 days during pregnancy. Basal intestinal morphology, immunolocalization of gut hormones responsible for food intake and proteins of intestinal barrier, activity of the intestinal brush border disaccharidases, apoptosis and proliferation in intestinal mucosa were analyzed in offspring at weaning (postnatal day 21). The results showed that in utero ACR exposure disturbs offspring gut structural and functional postnatal development in a time- and segment-depended manner and even a short prenatal exposure to ACR resulted in changes in intestinal morphology, immunolocalization of leptin and ghrelin and their receptors, barrier function, activity of gut enzymes and upregulation of apoptosis and proliferation. In conclusion, prenatal ACR exposure disturbed the proper postnatal development of small intestine.

Investigation of the effects of swimming exercises in rats given acrylamide

BACKGROUND

Acrylamide is a toxic substance used in industrial and laboratory processes. Acrylamide exposure has a toxic effect on many systems. Protective mechanisms should be developed against the effects caused by acrylamide.

OBJECTIVE

In our study, we investigated whether exercise has a protective effect against the changes that acrylamide will cause in pancreas.

METHODS

32 adult Sprague-Dawley male rats were used. Control group was given only saline. Exercise group was applied swimming exercise for 1hour daily for 4 weeks. Acrylamide group was given 50mg/kg acrylamide by gavage for 4 weeks. Acrylamide+exercise group was applied 50mg/kg acrylamide for 4 weeks and swimming exercise for 1hour daily. After the experiment, fasting blood glucose and oral glucose tolerance test measurements were performed. Then, blood and pancreas samples were taken.

RESULTS

Acrylamide exposure caused an increase in fasting blood glucose and oral glucose tolerance, a decrease in insulin levels and oxidative stress in acrylamide group. In exercise group, these values were similar to control group and no significant change was observed in acrylamide+exercise group. While there was an increase in the number of alpha cells in acrylamide group compared to the other groups, here was a decrease in the number of beta cells compared to control group.

CONCLUSION

We can say that acrylamide causes changes in the islets of Langerhans by affecting alpha and beta cell numbers. The protective effect of exercise on beta and alpha cell mass was not statistically significant in the acrylamide+exercise group. When the results were examined, the decrease in oxidative stress and the higher number of beta and alpha cells in the acrylamide+exercise group compared to the acrylamide group suggested that 4 weeks of swimming exercise may have an effect on acrylamide exposure.

The association between dietary acrylamide intake and the risk of type 2 diabetes incidence in the Tehran lipid and glucose study

This study aimed at investigating the association of acrylamide consumption with the incidence of type 2 diabetes (T2D) in adults. The 6022 subjects of the Tehran lipid and glucose study participants were selected. The acrylamide content of food items were summed and computed cumulatively across follow up surveys. Multivariable Cox proportional hazard regression analyses were performed to estimate the hazards ratio (HR) and 95% confidence interval (CI) of incident T2D. This study was done on men and women, respectively aged 41.5 ± 14.1 and 39.2 ± 13.0 years. The mean ± SD of dietary acrylamide intake was 57.0 ± 46.8 µg/day. Acrylamide intake was not associated with the incidence of T2D after adjusting for confounding variables. In women, a higher acrylamide intake was positively associated with T2D [HR (CI) for Q4: 1.13 (1.01-1.27), P trend: 0.03] after adjusting for confounding factors. Our results demonstrated that dietary intake of acrylamide was associated with an increased risk of T2D in women.

Harmonized human biomonitoring in European children, teenagers and adults: EU-wide exposure data of 11 chemical substance groups from the HBM4EU Aligned Studies (2014-2021)

As one of the core elements of the European Human Biomonitoring Initiative (HBM4EU) a human biomonitoring (HBM) survey was conducted in 23 countries to generate EU-wide comparable HBM data. This survey has built on existing HBM capacity in Europe by aligning national or regional HBM studies, referred to as the HBM4EU Aligned Studies. The HBM4EU Aligned Studies included a total of 10,795 participants of three age groups: (i) 3,576 children aged 6-12 years, (ii) 3,117 teenagers aged 12-18 years and (iii) 4,102 young adults aged 20-39 years. The participants were recruited between 2014 and 2021 in 11-12 countries per age group, geographically distributed across Europe. Depending on the age group, internal exposure to phthalates and the substitute DINCH, halogenated and organophosphorus flame retardants, per- and polyfluoroalkyl substances (PFASs), cadmium, bisphenols, polycyclic aromatic hydrocarbons (PAHs), arsenic species, acrylamide, mycotoxins (deoxynivalenol (total DON)), benzophenones and selected pesticides was assessed by measuring substance specific biomarkers subjected to stringent quality control programs for chemical analysis. For substance groups analyzed in different age groups higher average exposure levels were observed in the youngest age group, i.e., phthalates/DINCH in children versus teenagers, acrylamide and pesticides in children versus adults, benzophenones in teenagers versus adults. Many biomarkers in teenagers and adults varied significantly according to educational attainment, with higher exposure levels of bisphenols, phthalates, benzophenones, PAHs and acrylamide in participants (from households) with lower educational attainment, while teenagers from households with higher educational attainment have higher exposure levels for PFASs and arsenic. In children, a social gradient was only observed for the non-specific pyrethroid metabolite 3-PBA and di-isodecyl phthalate (DiDP), with higher levels in children from households with higher educational attainment. Geographical variations were seen for all exposure biomarkers. For 15 biomarkers, the available health-based HBM guidance values were exceeded with highest exceedance rates for toxicologically relevant arsenic in teenagers (40%), 3-PBA in children (36%), and between 11 and 14% for total DON, Σ (PFOA + PFNA + PFHxS + PFOS), bisphenol S and cadmium. The infrastructure and harmonized approach succeeded in obtaining comparable European wide internal exposure data for a prioritized set of 11 chemical groups. These data serve as a reference for comparison at the global level, provide a baseline to compare the efficacy of the European Commission's chemical strategy for sustainability and will give leverage to national policy makers for the implementation of targeted measures.

Evaluation of the genotoxic potential of acrylamide: Arguments for the derivation of a tolerable daily intake (TDI value)

This opinion of the Senate Commission on Food Safety (SKLM) of the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) presents arguments for an updated risk assessment of diet-related exposure to acrylamide (AA), based on a critical review of scientific evidence relevant to low dose exposure. The SKLM arrives at the conclusion that as long as an appropriate exposure limit for AA is not exceeded, genotoxic effects resulting in carcinogenicity are unlikely to occur. Based on the totality of the evidence, the SKLM considers it scientifically justified to derive a tolerable daily intake (TDI) as a health-based guidance value.

Protective effect of Aronia melanocarpa juice against acrylamide-induced cellular toxicity

Acrylamide (AA) a widely used industrial chemical is also formed during food processing by the Maillard reaction, which makes its exposure to humans almost unavoidable. In this study, we used Schizosaccharomyces pombe as a model organism to investigate AA toxicity (10 or 20 mM concentration) in eukaryotes. In S. pombe, AA delays cell growth causes oxidative stress by enhancement of ROS production and triggers excitement of the antioxidant defence system resulting in the division arrest. Aronia fruit contains a variety of health-promoting substances with considerable antioxidant potential. Therefore, Aronia juice supplementation was tested to evaluate its protective effect against AA-derived perturbations of the organism. Cell treatment with several Aronia juice concentrations ranging from 0 to 2% revealed the best protective effect of 1 or 2% Aronia juice solutions. Both chosen Aronia juice concentrations alleviated AA toxicity through the improvement of the antioxidant cell capacity and metabolic activity by their strong ROS scavenging property. Efficiency of Aronia juice cell protection is dose dependent as the 2% solution led to significantly higher cellular defence compared with 1%. Due to the high similarity of biological processes of S. pombe with higher eukaryotes, the protective effect of Aronia juice against AA toxicity might also apply to higher organisms.

Dietary Acrylamide Exposure and Cancer Risk: A Systematic Approach to Human Epidemiological Studies

Acrylamide, identified by the International Cancer Research Center as a possible carcinogenic compound to humans, is a contaminant formed as a result of the thermal process in many foods, such as coffee, French fries, biscuits and bread, which are frequently consumed by individuals in their daily lives. The biggest concern about acrylamide is that the health risks have not yet been fully elucidated. For this reason, many studies have been carried out on acrylamide in the food, nutrition and health equation. This study focused on epidemiological studies examining the associations between dietary acrylamide exposure and cancer risk. For this purpose, articles published in PubMed, Isı Web of Knowledge, Scopus and Science Direct databases between January 2002 and April 2022 were systematically examined using various keywords, and a total of 63 articles were included in the study. Although some studies on reproductive, urinary, gastrointestinal, respiratory and other systems and organs stated that there is a positive relationship between dietary acrylamide exposure and cancer risk, many publications did not disclose a relationship in this direction. Studies examining the relationship between dietary acrylamide exposure and cancer should be planned to include more people and foods in order to obtain more reliable results. Making research plans in this way is very important in terms of guiding health policies to be formed in the future.

Association between acrylamide exposure and sex hormones among premenopausal and postmenopausal women: NHANES, 2013-2016

PURPOSE

Acrylamide (AA) is a potential carcinogen that mainly comes from fried, baked and roasted foods, and Hb adducts of AA (HbAA) and its metabolite glycidamide (HbGA) are the biomarkers of its exposure. Increasing evidence suggests that AA is associated with various hormone-related cancers. This study aims to explore the association of HbAA and HbGA with female serum sex hormone concentrations.

METHODS

942 women from the National Health and Nutrition Examination Survey cycles (2013-2016) were included in this cross-sectional study. The associations between HbAA or HbGA or HbGA/HbAA and sex hormones were assessed by the multiple linear regression. Further stratified analyses were conducted to figure out the effects of menopausal status, BMI and smoking status on sex hormone levels.

RESULTS

Among all participants, 597 were premenopausal and 345 were postmenopausal. HbAA was positively associated with both two androgen indicators. Specifically, a ln-unit increase in HbAA was associated with 0.41 ng/dL higher ln(total testosterone, TT) (95% CI 0.00, 0.27) and 0.14 ng/dL higher ln(free testosterone) (95%CI 0.00, 0.28), respectively. However, HbGA concentrations had no association with sex hormones in the overall population. Additionally, HbGA/HbAA was negatively associated with TT and SHBG in the overall population as well as postmenopausal women. In stratified analysis, higher HbAA was associated with rising TT in postmenopausal women (β = 0.29, 95%CI 0.04, 0.53) and underweight/normal-weight women (β = 0.18, 95%CI 0.03, 0.33). Other indicators had no significant association detected in estradiol and sex hormone-binding globulin.

CONCLUSION

Our results revealed that HbAA was positively associated with androgen concentrations, especially in postmenopausal and BMI < 25 women.

An in vitro Approach to Protective Effect of Lactoferrin on Acrylamide-induced Oxidative Damage

Acrylamide is a compound that occurs with high temperature during food processing and causes oxidative damage. Recently, the importance of antioxidative components is increasing to prevent oxidative damage. Lactoferrin is an antioxidant protein mainly found in milk. Therefore, the aim of this study is to determine the dose-dependent protective effects of lactoferrin on oxidative damage caused by acrylamide. In this study, HepG2 cell lines were treated with lactoferrin doses (0, 25, 50, 100µM) and half maximal inhibitory concentration of acrylamide. After 24 hours malondialdehyde, superoxide dismutase, catalase and glutathione reductase levels were measured. Acrylamide significantly increased malondialdehyde levels in HepG2 cells compared to the control group; however, catalase, superoxide dismutase and glutathione reductace significantly reduced. On the other hand, added lactoferrin doses (50-100µM) significantly reduced lipid peroxidation levels. Besides, it was found that glutathione reductase, catalase and superoxide dismutase levels significantly increased. As a result, the protective effect of lactoferrin against the oxidative damage caused by acrylamide in HepG2 cells was determined. This effect is thought to be due to the antioxidant capacity of lactoferrin. In this context, it is recommended that more studies are carried out on the mechanism of action of lactoferrin on oxidative stress caused by acrylamide.

Ferric ions release from iron-binding protein: Interaction between acrylamide and human serum transferrin and the underlying mechanisms of their binding

Acrylamide (ACR) is a surprisingly common chemical due to its widespread use in industry and various other applications. However, its toxicity is a matter of grave concern for public health. Even worse, ACR is frequently detected in numerous fried or baked carbohydrate-rich foods due to the Maillard browning reaction. Herein, this study intends to delineate the underlying molecular mechanisms of Fe ions released from iron-binding protein transferrin (TF) after acrylamide binding by combining multiple methods, including multiple complementary spectroscopic techniques (UV-Vis, fluorescence, and circular dichroism spectroscopy), isothermal titration calorimetry, ICP-MS measurements, and modeling simulations. Results indicated that free Fe was released from TF only under high-dose ACR exposure (>100 μM). Acrylamide binding induced the loosening and unfolding of the backbone and polypeptide chain and destroyed the secondary structure of TF, thereby leading to protein misfolding and denaturation of TF and forming a larger size of TF agglomerates. Of which, H-binding and van der Waals force are the primary driving force during the binding interaction between ACR and TF. Further modeling simulations illustrated that ACR prefers to bind to the hinge region connecting the C-lobe and N-lobe, after that it attaches to the Fe binding sites of this protein, which is the cause of free Fe release from TF. Moreover, ACR interacted with the critical fluorophore residues (Tyr, Trp, and Phe) in the binding pocket, which might explain such a phenomenon of fluorescence sensitization. The two binding sites (Site 2 and Site 3) located around the Fe (III) ions with low-energy conformations are more suitable for ACR binding. Collectively, our study demonstrated that the loss of iron in TF caused by acrylamide-induced structural and conformational changes of transferrin.

Neuroprotection by melatonin against acrylamide-induced brain damage in pinealectomized rats

The current study aimed to evaluate the neuroprotective effect of exogenous melatonin against acrylamide (ACR)-induced oxidative stress and inflammatory and apoptotic responses in the brain tissues in pinealectomized rats (PINX). ACR is a toxic chemical carcinogen that occurs owing to the preparation of carbohydrate-rich foods at high temperatures or other thermal processes. The rats who underwent pinealectomy and sham pinealectomy were exposed to ACR (25 mg/kg b.w., orally) alone or with exogenous melatonin (10 mg/kg b.w., i.p.) for 21 consecutive days. Alterations of brain oxidant/antioxidant status, dopamine (DA), Brain-Derived Neurotropic Factor (BDNF) inflammatory mediator and apoptosis during exposure to ACR in pinealectomized rats were more than without pinealectomized rats. Histopathological changes were more in brain tissue of pinealectomized rats after ACR administration. Exogenous melatonin treatment in ACR -exposed rats following pinealectomy increased the activities of antioxidant enzymes such as superoxide dismutase (SOD) and catalase (CAT) and improved brain total antioxidant status (TAS) compared to PINX+ACR. Moreover, melatonin suppressed lipid peroxidation, inflammatory pathways and apoptosis in ACR-intoxicated brain tissues. In addition, after exposure to ACR on pinealectomized rats, melatonin treatment ameliorated BDNF and DA levels in brain tissues. Furthermore, exogenous melatonin intervention in ACR-intoxicated rats significantly rescued the architecture of neuronal tissues. In summary, the present study, for the first time, suggested that exogenous melatonin treatment could reduce oxidative damage by increasing the activities of antioxidant enzymes, inhibiting lipid peroxidation and inflammation, and improving histopathological alterations in the brain tissue of pinealectomized rats after ACR administration.

Acrylamide-Derived Ionome, Metabolic, and Cell Cycle Alterations Are Alleviated by Ascorbic Acid in the Fission Yeast

Acrylamide (AA), is a chemical with multiple industrial applications, however, it can be found in foods that are rich in carbohydrates. Due to its genotoxic and cytotoxic effects, AA has been classified as a potential carcinogen. With the use of spectrophotometry, ICP-OES, fluorescence spectroscopy, and microscopy cell growth, metabolic activity, apoptosis, ROS production, MDA formation, CAT and SOD activity, ionome balance, and chromosome segregation were determined in Schizosaccharomyces pombe. AA caused growth and metabolic activity retardation, enhanced ROS and MDA production, and modulated antioxidant enzyme activity. This led to damage to the cell homeostasis due to ionome balance disruption. Moreover, AA-induced oxidative stress caused alterations in the cell cycle regulation resulting in chromosome segregation errors, as 4.07% of cells displayed sister chromatid non-disjunction during mitosis. Ascorbic acid (AsA, Vitamin C), a strong natural antioxidant, was used to alleviate the negative impact of AA. Cell pre-treatment with AsA significantly improved AA impaired growth, and antioxidant capacity, and supported ionome balance maintenance mainly due to the promotion of calcium uptake. Chromosome missegregation was reduced to 1.79% (44% improvement) by AsA pre-incubation. Results of our multiapproach analyses suggest that AA-induced oxidative stress is the major cause of alteration to cell homeostasis and cell cycle regulation.

Protective efficacy of rutin against acrylamide-induced oxidative stress, biochemical alterations and histopathological lesions in rats

Acrylamide is a well-known neurotoxicant and carcinogen. Apart from industrial exposure, acrylamide is also found in different food products. The present study deals with in vivo experiment to test the protective effect of rutin against acrylamide induced toxicity in rats. The study was carried out on female rats with exposure of acrylamide at the dose of 38.27 mg/kg body weight, orally for 10 days followed by the therapy of rutin (05, 10, 20 and 40 mg/kg orally), for three consecutive days. All animals were sacrificed after 24 h of last treatment and various biochemical parameters in blood and tissue were investigated. Histopathology of liver, kidney and brain was also done. On administration of acrylamide for 10 days, neurotoxicity was observed in terms of decreased acetylcholinesterase activity and oxidative stress was observed in terms of increased lipid peroxidation, declined level of reduced glutathione, antioxidant enzymes (superoxide dismutase and catalase) in liver, kidney and brain. Acrylamide exposure increased the activities of serum transaminases, lipid profile, bilirubin, urea, uric acid and creatinine in serum indicating damage. Our experimental results conclude that rutin showed remarkable protection against oxidative DNA damage induced by acrylamide, which may be due to its antioxidant potential.

Association between Acrylamide Hemoglobin Adduct Levels and Depressive Symptoms in US Adults: NHANES 2013-2016

Acrylamide (AA) is widely present in heat-processed carbohydrate-rich food, cigarette smoke, and the environment. Prolonged exposure to AA may cause central nervous system damage. However, few epidemiologic studies assessed the association between hemoglobin adduct levels of AA or its metabolite glycidamide (GA) and depressive symptoms. We included 3595 US adults (≥18 years) from the National Health and Nutrition Examination Survey (NHANES) 2013-2016. Data for hemoglobin adduct levels from AA and GA (HbAA and HbGA) were used as a measure of internal dose. Depressive symptom data were from mental health questionnaires and measured by nine-item Patient Health Questionnaire (PHQ-9) scores. Results of logistic regression models showed a positive association between HbAA in quartile 4 and depressive symptoms with ORs and 95% CI of 2.47 (1.29, 4.77) [OR_{continuous HbAA} and 95% CI: 1.006 (1.000, 1.013)], but an inverse association was detected in quartiles 2 and 3 of HbGA/HbAA [0.62 (0.38, 0.99) and 0.54 (0.32, 0.92), respectively]. Especially, an association between HbAA and depressive symptoms was strengthened in smokers, in age 18-39 and 40-59 years and BMI 25-30 kg/m² groups. Further explorations are needed to study the found associations between HbAA, HbGA, and depressive symptoms.

Associating acrylamide internal exposure with dietary pattern and health risk in the general population of Taiwan

We determined the urinary levels of acrylamide (AA) metabolites of the general Taiwanese population, explore the association between AA internal exposure and dietary intake frequency, and assess the health risk. Urine samples and dietary questionnaires were collected from the subjects of the Nutrition and Health Survey in Taiwan. AA metabolite [N-acetyl-S-(propionamide)-cysteine (AAMA)] concentrations were analyzed by ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-ToF-MS). Multiple regression was used to examine associations between AA metabolite levels and dietary patterns. A total of 706 subjects were studied. We found that per increase in weekly frequency of sweetened beverages in the 6-11-years group (β = 0.322, p = 0.018) and oily snacks intakes in the 12-18-years group (β = 0.335, p = 0.012) will increase 10^β of urinary AAMA concentrations. Assuming that 50% of the AA intake is excreted as urinary AAMA, the Monte Carlo simulation showed that 1.75-19.48% among all age groups have exceeded the reference dose of 2 μg/kg-body weight/day.

Removal of color from pulp and paper mill wastewater- methods and techniques- A review

The pulp and paper industry consumes a huge amount of water and releases more polluted and colored wastewater every year. Many conventional techniques are used in the treatment of paper industry wastewater. However, for color removal from paper mill effluent, there is no proven method so far, on an industrial scale. Due to high energy input and high cost, there is an urgent need to find out a new technique that must be sustainable, economical, and environment friendly. Various methods have been investigated on bench scale and pilot scale also but no proven method for color removal on an industrial scale. The paper provides an overview of the color removal techniques from different sources of pulp and paper mill wastewater discharged by various industries. The review described various components involved in various processes for color removal from paper mill waste water. The present works focus on processes like chemical, chemical/physical, biological, physicochemical, and electrochemical applied in color removal from paper mill wastewater. The present review gives key information on the effectiveness, use, betterment, and limitations of numerous methods of treatment targeted at color removal from paper mill wastewater using various techniques still under evolution.

Comprehensive analysis of metabolic changes in rats exposed to acrylamide

Acrylamide (ACR) is a widely used environmentally hazardous compound that is known to be neurotoxic, genotoxic, carcinogenic, and reproductive toxicity. It is widely present in soil, water, agents used in chemical industries, and food. It can be distributed to all organs and tissues, and can cause damage to various human systems and those of other animals. Previous metabolomics studies have mainly focused on metabolites in serum and urine, but have lacked comprehensive analysis of major organs and tissues. In the current study, a gas chromatography-massspectrometry method was used to investigate mechanisms underlying organ toxicity, in an effort to identify potentially sensitive biomarkers in the main target tissues of rats after ACR exposure. Male Sprague-Dawley rats were assigned to two groups; a control group and a group treated with 20 mg kg^-1 ACR intragastrically for 6 weeks. Metabolite changes in the two groups were statistically analyzed. The respective numbers of altered metabolites in the hippocampus, cortex, kidney, serum, heart, liver, and kidney fat were 21, 21, 17, 5, 15, 14, and 6. There were 14 metabolic pathways related to amino acid, fatty acid, purine, and energy metabolism, revealing that the toxic mechanism of ACR may involve oxidative stress, inflammation, and amino acid metabolism and energy disorders.

Incorporation of high fructose corn syrup with different fructose levels into biscuit: An assessment of physicochemical and textural properties

This study examined the effects of different concentrations of high-fructose corn syrup (HFCS, 28%, 44%, 55%) used in biscuit formulation on the hydroxymethyl furfural (HMF) acrylamide content, and textural properties were investigated and compared with invert sugar and sucrose-incorporated samples. No significant difference in the chemical composition (moisture, fat, protein, and ash) among different samples was noted based on the results. The highest L* was associated with a control sample containing sugar and invert sugar, although an increase in F55 content decreased the L* value significantly (p < .05). The highest hardness value was correlated with control samples (6.5 N), although the sample with 12.5% F42 and 25% F55 demonstrated lower hardness 6.27 N, and the lowest hardness value (3.97 N) was related to the sample containing 12.5% F42 and 25% F28. The amounts of water activity of all samples were in the range of 0.22 to 0.29, with the highest amount related to the control sample. The SEM images showed a uniform surface with several holes for all the biscuits. The highest and lowest (HMF) levels were related to the samples containing 25% F55 (46.04) and 12.5% F42 with 2.36 ppm. The control sample with the acrylamide amount of 28.50 ppb and the sample containing 12.5% F42 and 25% F55 with the acrylamide amount of 27.33 ppb showed the highest acrylamide content.

Acrylamide impairs the developmental potential of germinal vesicle oocytes by inducing mitochondrial dysfunction and autophagy/apoptosis in mice

Background: Acrylamide (ACR), an important endogenous contaminant in carbohydrate-rich foods, has been involved in various negative effects on multiple organ networks, including the reproductive system. Previous studies have reported that ACR affects oocyte quality and fertility. Purpose: This study aimed to explore the toxic effects and regulatory mechanisms of ACR on mouse germinal vesicle (GV) oocytes. Research Design: In this study, adult female mice were exposed to ACR at 10 mg/kg/day/body weight through their drinking water continuously for 4 weeks. Study Sample and Data Analysis: The mitochondrial function, autophagy/apoptosis, and development potential of GV oocytes were investigated. Results: The results showed that ACR reduced the oocyte diameter, sperm-binding ability, parthenogenetic activation and in vitro fertilization (IVF) rate, and development potential of pre-implantation embryos. We also found that ACR exposure disrupted chromatin configuration, mitochondrial distribution, and membrane potential (Δφm) of oocytes. Actin filament expression was significantly reduced in both the membrane and cytoplasm of mouse oocytes. Moreover, ACR exposure increased LC3-positive signals, early apoptosis rate, aberrant ATG3, ATG5, LC3, Beclin1, and mTOR mRNA expression. Conclusions: These results suggest that ACR exposure can affect the developmental potential of GV oocytes by inducing mitochondrial dysfunction, actin filament assembly, and autophagy/apoptosis.

Instrumentation for Routine Analysis of Acrylamide in French Fries: Assessing Limitations for Adoption

The purpose of this experimental review was to detect acrylamide in French fries using methods most adaptable to the food process industry for quality control assessment of products. French fries were prepared at different cook times using the same fryer oil over a five-day period to assess the influence of oil degradation and monitor trends in acrylamide formation. Acrylamide detection was performed using LC-MS, GC-MS and FT-NIR. The low levels of acrylamide produced during frying, low molecular weight of the analyte, and complexity of the potato matrix make routine acrylamide measurement challenging in a well-outfitted analytical lab with trained personnel. The findings of this study are presented from the perspective of pros and cons of each acrylamide measurement method in enough detail for food processors to appraise the method that may work best for them based on their available instrumentation and extent of personnel training.

Effects of Acrylamide-Induced Vasorelaxation and Neuromuscular Blockage: A Rodent Study

Acrylamide (ACR), which is formed during the Maillard reaction, is used in various industrial processes. ACR accumulation in humans and laboratory animals results in genotoxicity, carcinogenicity, neurotoxicity, and reproductive toxicity. In this study, we investigated the mechanisms by which ACR may induce vasorelaxation and neuromuscular toxicity. Vasorelaxation was studied using an isolated rat aortic ring model. The aortic rings were divided into the following groups: with or without endothelium, with nitric oxide synthase (NOS) inhibition, with acetylcholine receptor inhibition, and with extracellular calcium inhibition. Changes in tension were used to indicate vasorelaxation. Neuromuscular toxicity was assessed using a phrenic nerve-diaphragm model. Changes in muscle contraction stimulated by the phrenic nerve were used to indicate neuromuscular toxicity. ACR induced the vasorelaxation of phenylephrine-precontracted aortic rings, which could be significantly attenuated by NOS inhibitors. The results of the phrenic nerve-diaphragm experiments revealed that ACR reduced muscle stimulation and contraction through nicotinic acetylcholine receptor (AChR). ACR-induced vasotoxicity was regulated by NOS through the aortic endothelium. Nicotinic AChR regulated ACR-induced neuromuscular blockage.

Metabolomic Profiling and Neuroprotective Effects of Purslane Seeds Extract Against Acrylamide Toxicity in Rat's Brain

AIM

Acrylamide (ACR) is an environmental pollutant with well-demonstrated neurotoxic and neurodegenerative effects in both humans and experimental animals. The present study aimed to investigate the neuroprotective effect of Portulaca oleracea seeds extract (PSE) against ACR-induced neurotoxicity in rats and its possible underlying mechanisms. PSE was subjected to phytochemical investigation using ultra-high-performance liquid chromatography (UPLC) coupled with quantitative time of flight mass spectrometry (qTOF-MS). Multivariate, clustering and correlation data analyses were performed to assess the overall effects of PSE on ACR-challenged rats. Rats were divided into six groups including negative control, ACR-intoxicated group (10 mg/kg/day), PSE treated groups (200 and 400 mg/kg/day), and ACR + PSE treated groups (200 and 400 mg/kg/day, respectively). All treatments were given intragastrically for 60 days. PSE markedly ameliorated brain damage as evidenced by the decreased lactate dehydrogenase (LDL), increased acetylcholinesterase (AchE) activities, as well as the increased brain-derived neurotrophic factor (BDNF) that were altered by the toxic dose of ACR. In addition, PSE markedly attenuated ACR-induced histopathological alterations in the cerebrum, cerebellum, hippocampus and sciatic nerve and downregulated the ACR-inclined GFAP expression. PSE restored the oxidative status in the brain as indicated by glutathione (GSH), lipid peroxidation and increased total antioxidant capacity (TAC). PSE upregulated the mRNA expression of protein kinase B (AKT), which resulted in an upsurge in its downstream cAMP response element-binding protein (CREB)/BDNF mRNA expression in the brain tissue of ACR-intoxicated rats. All exerted PSE beneficial effects were dose-dependent, with the ACR-challenged group received PSE 400 mg/kg dose showed a close clustering to the negative control in both unsupervised principal component analysis (PCA) and supervised orthogonal partial least square discriminant analysis (OPLS-Da) alongside with the hierarchical clustering analysis (HCA). The current investigation confirmed the neuroprotective capacity of PSE against ACR-induced brain injury, and our findings indicate that AKT/CREB pathways and BDNF synthesis may play an important role in the PSE-mediated protective effects against ACR-triggered neurotoxicity.

Long-term acrylamide exposure exacerbates brain and lung pathology in a mouse malaria model

The consumption of dietary acrylamide (ACR), a carcinogen, results in the dysfunction of various organs and the immune system. However, the impact of ACR exposure on the progression of infectious diseases is unknown. This study investigated the effect of ACR on the progression of malaria infection using a mouse model of malaria. C57BL/6 mice were continuously treated with ACR at a dose of 20 mg/kg bodyweight/day for six weeks (long-term exposure) or phosphate-buffered saline (PBS). Next, the mice were infected with the rodent malaria parasite, Plasmodium berghei NK65 (PbNK). Parasitemia and survival rate were analyzed in the different treatment groups. Magnetic resonance imaging (MRI) and histopathological analyses were performed to evaluate the effect of ACR exposure on the morphology of various organs. Long-term ACR exposure exacerbated PbNK-induced multiorgan dysfunction. MRI and histopathological analysis revealed signs of encephalomeningitis and acute respiratory distress syndrome in the PbNK-infected long-term ACR exposure mice, which decreased the survival rate of mice, but not in the PbNK-infected long-term PBS exposure group. These findings enhance our understanding of the impact of ACR on the progression of infectious diseases, such as malaria.

Biomedical rationale for acrylamide regulation and methods of detection

Acrylamide is the product of the Maillard reaction, which occurs when starchy, asparagine-rich foods including potato or grain products and coffee are fried, baked, roasted, or heated. Studies in rodents provide evidence that acrylamide is carcinogenic and a male reproductive harmful agent when administered in exceedingly high levels. A 2002 study identified acrylamide in popular consumer food and beverage products, stimulating the European Union (EU) and California to legislate public notice of acrylamide presence in fried and baked foods, and coffee products. The regulatory legislation enacted in the EU and California has scientists working to develop foods and processes aimed at reducing acrylamide formation and advancing rapid and accurate analytical methods for the quantitative and qualitative determination of acrylamide in food and beverage products. The purpose of this review is to survey the studies performed on rodents and humans that identified the potential health impact of acrylamide in the human diet, and provide insight into established and emerging analytical methods used to detect acrylamide in blood, aqueous samples, and food.

Dietary Acrylamide Intake and the Risks of Renal Cell, Prostate, and Bladder Cancers: A Japan Public Health Center-Based Prospective Study

Acrylamide can be carcinogenic to humans. However, the association between the acrylamide and the risks of renal cell, prostate, and bladder cancers in Asians has not been assessed. We aimed to investigate this association in the Japan Public Health Center-based Prospective Study data in 88,818 Japanese people (41,534 men and 47,284 women) who completed a food frequency questionnaire in the five-year follow-up survey in 1995 and 1998. A validated food frequency questionnaire was used to assess the dietary acrylamide intake. Cox proportional hazard regression models were used to estimate hazard ratios and 95% confidence intervals (CIs). During a mean follow-up of 15.5 years (15.2 years of prostate cancer), 208 renal cell cancers, 1195 prostate cancers, and 392 bladder cancers were diagnosed. Compared to the lowest quintile of acrylamide intake, the multivariate hazard ratios for the highest quintile were 0.71 (95% CI: 0.38–1.34, p for trend = 0.294), 0.96 (95% CI: 0.75–1.22, p for trend = 0.726), and 0.87 (95% CI: 0.59–1.29, p for trend = 0.491) for renal cell, prostate, and bladder cancers, respectively, in the multivariate-adjusted model. No significant associations were observed in the stratified analyses based on smoking. Dietary acrylamide intake was not associated with the risk of renal cell, prostate, and bladder cancers.

Comprehensive Study on the Acrylamide Content of High Thermally Processed Foods

Acrylamide (AA) formation in starch-based processed foods at elevated temperatures is a serious health issue as it is a toxic and carcinogenic substance. However, the formation of more AA entangles with modern-day fast food industries, and a considerable amount of this ingredient is being consumed by fast food eaters inadvertently throughout the world. This article reviews the factors responsible for AA formation pathways, investigation techniques of AA, toxicity, and health-related issues followed by mitigation methods that have been studied in the past few decades comprehensively. Predominantly, AA and hydroxymethylfurfural (HMF) are produced via the Maillard reaction and can be highlighted as the major heat-induced toxins formulated in bread and bakery products. Epidemiological studies have shown that there is a strong relationship between AA accumulation in the body and the increased risk of cancers. The scientific community is still in a dearth of technology in producing AA-free starch-protein-fat-based thermally processed food products. Therefore, this paper may facilitate the food scientists to their endeavor in developing mitigation techniques pertaining to the formation of AA and HMF in baked foods in the future.

Protective effect of rapamycin against acrylamide-induced hepatotoxicity: The associations between autophagy, apoptosis, and necroptosis

Acrylamide (ACRL) was demonstrated to induce hepatotoxicity and programmed cell death (PCD). Rapamycin (RAPA)-induced autophagy had been reported to limit the progression of hepatocellular injury in experimental models. This research was designed to study two death pathways involved in ACRL-induced hepatotoxicity and the modulating effect of RAPA on the resulting hepatic injury. Thirty-six adult male rats were divided into three groups: control group, ACRL-treated group (20 mg kg/day), and the last group co-treated with ACRL plus RAPA (0.5 mg kg/day). Drugs were administered for 21 days via oral gavage. Blood samples were collected to assess alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Livers were dissected; parts were used for detection of superoxide dismutase (SOD) and malondialdehyde (MDA) tissue levels. Other parts were processed for hematoxylin and eosin, Masson's trichrome staining, immunostaining for microtubule-associated proteins 1A/1B light chain 3B (LC3), ubiquitin-binding protein (p62), caspase-3, and receptor-interacting protein kinase 1 (RIPK1). ACRL induced a significant elevation in ALT, AST, MDA levels, and reduction in the SOD level. ACRL also induced hepatocellular injury, fibrosis, and defective autophagy indicated by elevation of LC3 and p62 and increased p62/LC3 ratio. Moreover, it increased the apoptotic (caspase-3) and necroptotic (RIPK1) markers expression. RAPA significantly reduced liver enzymes, oxidative stress, fibrosis, and improved liver histology. Moreover, RAPA decreased p62/LC3 ratio indicated enhanced autophagy, and significantly reduced caspase-3 and RIPK1 expression. In conclusion, RAPA maintained autophagic activity which may save the hepatocytes from PCD and enhance cell viability.

Acrylamide inhibits autophagy, induces apoptosis and alters cellular metabolic profiles

Acrylamide (ACR) is generated during thermal processing of carbohydrate-rich foods at high temperature and can directly enter the body through ingestion, inhalation and skin contact. The toxicity of ACR has been widely studied. The main results of these studies show that exposure to ACR can cause neurotoxicity in both animals and humans, and show reproductive toxicity and carcinogenicity in rodent animal models. However, the mechanism of toxicity of ACR has not been studied by metabolomics approaches, and the effect of ACR on autophagy remains unknown. Here, U₂OS cell were treated with ACR 6 and 24 h and collected for further study. We have demonstrated that ACR inhibited autophagic flux, and increased ROS content. Accumulation of ROS resulted in increase of apoptosis rates and secretion of inflammatory factors. In addition, significant differences in metabolic profiles were observed between ACR treated and control cells according to multiple analysis models. A total of 73 key differential metabolites were identified. They were involved in multiple metabolic pathways. Among them, exposure to ACR caused glycolysis/gluconeogenesis attenuation by decreasing levels of glycolytic intermediates, reduced the rate of the TCA cycle, while elevating levels of several amino acid metabolites and lipid metabolites. In summary, our study provides useful evidence of cytotoxicity caused by ACR via metabolomics and multiple bioanalytic methods.

Effect of Acrylamide Supplementation on the Population of Vasoactive Intestinal Peptide (VIP)-Like Immunoreactive Neurons in the Porcine Small Intestine

Acrylamide is one of the harmful substances present in food. The present study aimed to establish the effect of acrylamide supplementation in tolerable daily intake (TDI) dose (0.5 µg/kg b.w./day) and a dose ten times higher than TDI (5 µg/kg b.w./day) on the population of vasoactive intestinal peptide-like immunoreactive (VIP-LI) neurons in the porcine small intestine and the degree of the co-localization of VIP with other neuroactive substances (neuronal nitric oxide synthase (nNOS), substance P (SP), and cocaine- and amphetamine-regulated transcript peptide (CART)). In our work, 15 Danish landrace gilts (5 in each experimental group) received capsules (empty or with low or high doses of acrylamide) for a period of 28 days with their morning feeding. Using double immunofluorescence staining, we established that acrylamide supplementation increased the number of neurons showing immunoreactivity towards VIP in all types of enteric nervous system (ENS) plexuses and fragments of the small intestine studied. Moreover, both doses of acrylamide led to changes in the degree of co-localization of VIP with nNOS, SP, and CART in intramural neurons. The observed changes may be the adaptation of neurons to local inflammation, oxidative stress, or the direct toxic effects of acrylamide on intestinal neurons, also referred to as neuronal plasticity.

Dietary Acrylamide Intake and the Risk of Pancreatic Cancer: The Japan Public Health Center-Based Prospective Study

Acrylamide is a probable carcinogen in humans. Few studies have assessed dietary acrylamide intake and the risk of pancreatic cancer; however, these studies are based on Western populations. Our purpose was to investigate the association of dietary acrylamide intake with the risk of pancreatic cancer utilizing data from the Japan Public Health Center-based Prospective Study. We evaluated the data of 89,729 participants aged 45-74 years, who replied to a questionnaire on past medical history and lifestyle habits from 1995-1998. Dietary acrylamide intake was estimated utilizing a validated food frequency questionnaire. We calculated the hazard ratios and 95% confidence intervals by using Cox proportional-hazards regression models. The average follow-up was 15.2 years, and 576 cases of pancreatic cancer were diagnosed. In the multivariate-adjusted model, an association between dietary acrylamide intake and pancreatic cancer risk was not demonstrated (hazard ratio for the highest vs. lowest quartile = 0.83, 95% confidence interval: 0.65-1.05, p for trend = 0.07). Furthermore, in the analyses stratified by sex, smoking status, coffee consumption, green tea consumption, alcohol consumption, and body mass index, no significant association was detected. Dietary acrylamide intake was not associated with the pancreatic cancer risk in Japanese individuals.

Effects of acrylamide on protein degradation pathways in human liver-derived cells and the efficacy of N-acetylcysteine and curcumin

Acrylamide is a harmful chemical, and its metabolism occurs mainly in the liver. Acrylamide can form adducts on proteins. Protein homeostasis is vital for metabolic and secretory functions of the liver. No study has investigated the effect of acrylamide on the ubiquitin-proteasome system (UPS). Also, the effect of acrylamide on autophagy and its regulation is not fully known. We aimed to investigate the effects of acrylamide on the UPS, autophagy, mammalian target of rapamycin (mTOR), and heat shock protein 70 (HSP70) in HepG2 cells as well as to examine the effects of N-acetylcysteine and curcumin on these parameters in acrylamide-treated cells. HepG2 cells were initially treated with variable concentrations of acrylamide (0.01-0.1-1-10 mM) for 24 hours. Then, HepG2 cells were treated with 5 mM N-acetylcysteine and 6.79 µM curcumin in the presence of 10 mM acrylamide for 24 hours. Cell viability was evaluated by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay. Ubiquitinated protein, mTOR, microtubule-associated proteins 1 A/1B light chain 3B-II (LC3B-II), and HSP70 levels were measured by immunoblotting. Acrylamide at 10 mM concentration, without any significant change at lower concentrations, caused an increase in ubiquitinated protein, LC3B-II, and HSP70 levels and a decrease in mTOR phosphorylation. Furthermore, 5 mM N-acetylcysteine caused a decrease in ubiquitinated protein and HSP70 levels; however, 6.79 µM curcumin did not affect 10 mM in acrylamide-treated cells. Our study showed that acrylamide at high concentration inhibits UPS and mTOR, activates autophagy, and increases HSP70 levels in HepG2 cells, and N-acetylcysteine reduces UPS inhibition and HSP70 levels in acrylamide-treated cells.

Risk of exposure to acrylamide

OBJECTIVES

Acrylamide is a toxic compound that can be found it both occupational and non-occupational environments. This study focuses on its sources and health effects of its exposure.

METHODS

Adverse effects of acrylamide, especially carcinogenic, genotoxic, and teratogenic were reported in many studies conducted on animals. Neurotoxicity was reported in workers exposed to acrylamide in the occupational environment. Another important source of populations' exposure to acrylamide is their nutrition.

RESULTS

This study focuses on humans' exposure to acrylamide from various sources and its harmful effects on their health.

CONCLUSIONS

Dietary intake of acrylamide, as well as occupational exposure, cigarette smoking, cosmetics usage and other environmental sources could have a significant effect on human health.

The Coffee-Acrylamide Apparent Paradox: An Example of Why the Health Impact of a Specific Compound in a Complex Mixture Should Not Be Evaluated in Isolation

The health implications of acrylamide in food are a matter of concern based on toxicological studies in rodents, which showed that doses of acrylamide more than 100 times higher than those estimated to result from dietary exposure in humans are carcinogenic; however, the cancer types reported in rodents are species-specific, and whether these results can be extrapolated to humans is still in question. In fact, human epidemiological studies revealed a general lack of association between dietary acrylamide exposure and the incidence of different cancer types. Even occupational exposure to acrylamide, resulting in acrylamide exposure nearly 10 times higher than dietary exposure, did not increase tumor occurrence. Furthermore, the consumption of coffee, which is a main contributor of dietary acrylamide exposure, actually decreases the overall incidence of cancer in humans and afford global health benefits, increasing both lifespan and healthspan on ageing. This paradox clearly illustrates the risk of evaluating an individual molecule independently of its complete food matrix, which may have other components that completely override the effects of the considered molecule.

Multicomponent DNA Polymerization Motor Gels

Hydrogels with the ability to change shape in response to biochemical stimuli are important for biosensing, smart medicine, drug delivery, and soft robotics. Here, a family of multicomponent DNA polymerization motor gels with different polymer backbones is created, including acrylamide-co-bis-acrylamide (Am-BIS), poly(ethylene glycol) diacrylate (PEGDA), and gelatin-methacryloyl (GelMA) that swell extensively in response to specific DNA sequences. A common mechanism, a polymerization motor that induces swelling is driven by a cascade of DNA hairpin insertions into hydrogel crosslinks. These multicomponent hydrogels can be photopatterned into distinct shapes, have a broad range of mechanical properties, including tunable shear moduli between 297 and 3888 Pa and enhanced biocompatibility. Human cells adhere to the GelMA-DNA gels and remain viable during ≈70% volumetric swelling of the gel scaffold induced by DNA sequences. The results demonstrate the generality of sequential DNA hairpin insertion as a mechanism for inducing shape change in multicomponent hydrogels, suggesting widespread applicability of polymerization motor gels in biomaterials science and engineering.

Revisiting the evidence for genotoxicity of acrylamide (AA), key to risk assessment of dietary AA exposure

The weight of evidence pro/contra classifying the process-related food contaminant (PRC) acrylamide (AA) as a genotoxic carcinogen is reviewed. Current dietary AA exposure estimates reflect margins of exposure (MOEs) < 500. Several arguments support the view that AA may not act as a genotoxic carcinogen, especially not at consumer-relevant exposure levels: Biotransformation of AA into genotoxic glycidamide (GA) in primary rat hepatocytes is markedly slower than detoxifying coupling to glutathione (GS). Repeated feeding of rats with AA containing foods, bringing about uptake of 100 µg/kg/day of AA, resulted in dose x time-related buildup of AA-hemoglobin (Hb) adducts, whereas GA-Hb adducts remained within the background. Since hepatic oxidative biotransformation of AA into GA was proven by simultaneous urinary mercapturic acid monitoring it can be concluded that at this nutritional intake level any GA formed in the liver from AA is quantitatively coupled to GS to be excreted as mercapturic acid in urine. In an oral single dose–response study in rats, AA induced DNA N⁷-GA-Gua adducts dose-dependently in the high dose range (> 100 µg/kg b w). At variance, in the dose range below 100 µg/kg b.w. down to levels of average consumers exposure, DNA N⁷ -Gua lesions were found only sporadically, without dose dependence, and at levels close to the lower bound of similar human background DNA N⁷-Gua lesions. No DNA damage was detected by the comet assay within this low dose range. GA is a very weak mutagen, known to predominantly induce DNA N⁷-GA-Gua adducts, especially in the lower dose range. There is consensus that DNA N⁷-GA-Gua adducts exhibit rather low mutagenic potency. The low mutagenic potential of GA has further been evidenced by comparison to preactivated forms of other process-related contaminants, such as N-Nitroso compounds or polycyclic aromatic hydrocarbons, potent food borne mutagens/carcinogens. Toxicogenomic studies provide no evidence supporting a genotoxic mode of action (MOA), rather indicate effects on calcium signalling and cytoskeletal functions in rodent target organs. Rodent carcinogenicity studies show induction of strain- and species-specific neoplasms, with MOAs not considered likely predictive for human cancer risk. In summary, the overall evidence clearly argues for a nongenotoxic/nonmutagenic MOA underlying the neoplastic effects of AA in rodents. In consequence, a tolerable intake level (TDI) may be defined, guided by mechanistic elucidation of key adverse effects and supported by biomarker-based dosimetry in experimental systems and humans.

Mode of action-based risk assessment of genotoxic carcinogens

The risk assessment of chemical carcinogens is one major task in toxicology. Even though exposure has been mitigated effectively during the last decades, low levels of carcinogenic substances in food and at the workplace are still present and often not completely avoidable. The distinction between genotoxic and non-genotoxic carcinogens has traditionally been regarded as particularly relevant for risk assessment, with the assumption of the existence of no-effect concentrations (threshold levels) in case of the latter group. In contrast, genotoxic carcinogens, their metabolic precursors and DNA reactive metabolites are considered to represent risk factors at all concentrations since even one or a few DNA lesions may in principle result in mutations and, thus, increase tumour risk. Within the current document, an updated risk evaluation for genotoxic carcinogens is proposed, based on mechanistic knowledge regarding the substance (group) under investigation, and taking into account recent improvements in analytical techniques used to quantify DNA lesions and mutations as well as "omics" approaches. Furthermore, wherever possible and appropriate, special attention is given to the integration of background levels of the same or comparable DNA lesions. Within part A, fundamental considerations highlight the terms hazard and risk with respect to DNA reactivity of genotoxic agents, as compared to non-genotoxic agents. Also, current methodologies used in genetic toxicology as well as in dosimetry of exposure are described. Special focus is given on the elucidation of modes of action (MOA) and on the relation between DNA damage and cancer risk. Part B addresses specific examples of genotoxic carcinogens, including those humans are exposed to exogenously and endogenously, such as formaldehyde, acetaldehyde and the corresponding alcohols as well as some alkylating agents, ethylene oxide, and acrylamide, but also examples resulting from exogenous sources like aflatoxin B1, allylalkoxybenzenes, 2-amino-3,8-dimethylimidazo[4,5-f] quinoxaline (MeIQx), benzo[a]pyrene and pyrrolizidine alkaloids. Additionally, special attention is given to some carcinogenic metal compounds, which are considered indirect genotoxins, by accelerating mutagenicity via interactions with the cellular response to DNA damage even at low exposure conditions. Part C finally encompasses conclusions and perspectives, suggesting a refined strategy for the assessment of the carcinogenic risk associated with an exposure to genotoxic compounds and addressing research needs.

Interaction of Acrylamide, Acrolein, and 5-Hydroxymethylfurfural with Amino Acids and DNA

Acrylamide, acrolein, and 5-hydroxymethylfurfural (HMF) are food-borne toxicants produced during the thermal processing of food. The α,β-unsaturated carbonyl group or aldehyde group in their structure can react easily with the amino, imino, and thiol groups in amino acids, proteins, and DNA via Michael addition and nucleophilic reactions in food and in vivo. This work reviews the interaction pathways of three toxins with amino acids and the cytotoxicity and changes after the digestion and absorption of the resulting adducts. Their interaction with DNA is also discussed. Amino acids ubiquitously exist in foods and are added as nutrients or used to control these food-borne toxicants. Hence, the interaction widely occurring in foods would greatly increase the internal exposure of these toxins and their derived compounds after food intake. This review aims to encourage further investigation on toxin-derived compounds, including their types, exposure levels, toxicities, and pharmacokinetics.

Is Acrylamide as Harmful as We Think? A New Look at the Impact of Acrylamide on the Viability of Beneficial Intestinal Bacteria of the Genus Lactobacillus

The impact of acrylamide (AA) on microorganisms is still not clearly understood as AA has not induced mutations in bacteria, but its epoxide analog has been reported to be mutagenic in Salmonella strains. The aim of the study was to evaluate whether AA could influence the growth and viability of beneficial intestinal bacteria. The impact of AA at concentrations of 0–100 µg/mL on lactic acid bacteria (LAB) was examined. Bacterial growth was evaluated by the culture method, while the percentage of alive, injured, and dead bacteria was assessed by flow cytometry after 24 h and 48 h of incubation. We demonstrated that acrylamide could influence the viability of the LAB, but its impact depended on both the AA concentration and the bacterial species. The viability of probiotic strain Lactobacillus acidophilus LA-5 increased while that of Lactobacillus plantarum decreased; Lactobacillus brevis was less sensitive. Moreover, AA influenced the morphology of L. plantarum, probably by blocking cell separation during division. We concluded that acrylamide present in food could modulate the viability of LAB and, therefore, could influence their activity in food products or, after colonization, in the human intestine.

Minocycline protects against acrylamide-induced neurotoxicity and testicular damage in Sprague-Dawley rats

This study investigated the protective effects of minocycline against acrylamide (ACR)-induced neurotoxicity and testicular damage in Sprague-Dawley rats. Forty rats were divided into five groups (eight rats each). Group I received saline (0.5 mL/rat) daily for 10 days and served as the untreated control group. Group II received ACR (30 mg/kg body weight (b.w.)) daily for 10 days. Group III received ACR (30 mg/kg b.w.) daily for 10 days and subsequently minocycline (60 mg/kg b.w.) for five days. Group IV received ACR (30 mg/kg b.w.) daily for 10 days followed by saline for five days and served as the control group for the ACR-minocycline-treated group. Group V received minocycline (60 mg/kg b.w.) for five days. All treatments were administered orally. Rats in group I and V showed normal locomotor behavior and normal histology of the brain and testes. Administration of ACR (Group II and IV) resulted in weight loss and gait abnormalities. Furthermore, neuronal degeneration in the hippocampus and cerebellum and degeneration of the seminiferous tubular epithelium with formation of spermatid giant cells were observed. Ultrastructurally, ACR specifically damaged spermatogonia and spermatocytes. Acrylamide was also seen to cause a significant increase of malondialdehyde levels in the brain and testes. Treatment of ACR-administered rats with minocycline (Group III) significantly alleviated the loss of body weight and improved locomotor function. Minocycline also ameliorated neuronal degeneration and seminiferous tubular damage and decreased malondialdehyde concentrations. In conclusion, minocycline protects against neurotoxic effects of acrylamide and seminiferous tubular damage. Decreasing lipid peroxidation by minocycline might play a role in such protection.

Effect of Acrylamide Supplementation on the CART-, VAChT-, and nNOS-Immunoreactive Nervous Structures in the Porcine Stomach

Acrylamide is found in food products manufactured with high-temperature processing, and exposure to acrylamide contained in food products may cause a potential risk to human health. The aim of this investigation was to demonstrate the changes in the population of CART-, nNOS-, and VAChT-immunoreactive enteric neurons in the porcine stomach in response to supplementation of low and high acrylamide doses. The study was carried out with 15 Danish landrace gilts divided into three experimental groups: the control group-animals were administered empty gelatine capsules; the low-dose group-animals were administrated a tolerable daily intake (TDI) dose (0.5 µg/kg of body weight (b.w.)/day) of acrylamide capsules, and the high-dose group-animals were administrated high-dose (ten times higher than TDI: 5 µg/kg b.w./day) acrylamide capsules for 28 days. Using the double immunofluorescence staining method, it was established that supplementation with low and high doses of acrylamide resulted in alterations of the porcine stomach neuron phenotype, which was reflected in an increased number of CART-, VAChT-, and nNOS-immunoreactive neurons. These changes were accompanied by an increased density of CART-, VAChT-, and nNOS-positive fibres. The results suggest that the enteric nervous system plays an important role in protecting the gastrointestinal tract during acrylamide intoxication.

Synthetic Chemicals and Cardiometabolic Health Across the Life Course Among Vulnerable Populations: a Review of the Literature from 2018 to 2019

PURPOSE OF REVIEW

Although vulnerable populations are disproportionately exposed to synthetic chemicals with endocrine disrupting properties, few recent reviews have summarized the impact of synthetic chemicals on cardiometabolic health among these groups.

RECENT FINDINGS

Of 37 eligible epidemiological studies among vulnerable populations published between January 2018 and April 2019 in which over half were prospective, the most investigated populations were pregnant women and children. Racial/ethnic minorities, individuals of low socioeconomic status (SES), and those occupationally exposed were studied the least. The most studied persistent organic pollutants (POPs) were per-/poly-fluoroalkyl substances (PFAS), and the most studied non-POPs were phenols. Across chemical classes, studies found certain POPs (e.g., PFAS) and non-POPs (i.e., phenols, phthalates, and parabens) to be associated with gestational diabetes and dysregulated glucose metabolism. Results for other cardiometabolic health outcomes were inconsistent but suggested certain chemicals may negatively affect cardiometabolic health. Synthetic chemicals likely adversely affect cardiometabolic health, but current findings were inconclusive. Few recent studies focused on racial/ethnic minorities, low SES, and occupationally exposed populations. To address poor cardiometabolic health and related disparities, more studies across vulnerable populations are warranted.